UNSC Marine Expeditionary Reconnaissance

"Les peuples comme les astres ont le droit d’éclipse. Et tout est bien, pourvu que la lumière revienne et que l’éclipse ne dégénère pas en nuit."

- Les Misérables (1862), Myrmidon Program motto

The Myrmidon Detachment, formally known as SPARTAN Detachment IV or Task Force Myrmidon, was an advanced special operations force operated by the UNSC Office of Naval Intelligence and the UNSC Special Operations Command.

Instigated in 2578, the Myrmidon initiative was the "second epoch" of the SPARTAN Program, integrating novel biological augmentations, warfighting technologies, and combat philosophies to create futuristic special forces that fulfilled the UNSC's requirement for advanced special forces to enable mankind's survival in an evolving and demanding galaxy.

The Myrmidons would partake in some of the climatic events of UNSC history, notably participating in the Midgard Campaign, the Beyond Veil's Azure Crisis, and the Dashan Campaign.

Overview
The Myrmidon Detachment was a battalion-scale joint special warfare unit operated by the UNSC Office of Naval Intelligence and the UNSC Special Operations Command.

It was centered around the "Myrmidons", fourth-generation SPARTAN child soldiers that represented the futuristic iterations of their predecessors, the SPARTAN-Is, the SPARTAN-IIs, and the SPARTAN-IIIs of the Human-Covenant War Era. The Myrmidons were the second iteration of the SPARTAN paradigm, the epitome of mankind's technologies and strategic doctrines in the Post-War Era.

The Myrmidon initiative drew from nearly one century of SPARTAN warfare and lessons learned from all three previous SPARTAN battalions. However, because the conceptual advances and core values of the fourth-generation Myrmidons were so striking different from the preceding three SPARTAN programs, instead of merely being labeled "SPARTAN-IVs", the Office of Naval Intelligence would name these fourth-generation soldiers as "Myrmidons", in honor of the Myrmidons of Greek mythology, another Greek warfighting tribe similar to the Spartans in ancient times.

Although the Myrmidon Detachment was centered upon these futuristic child soldiers, the successors to the prior SPARTANs, the detachment as a whole was a combined-arms unit, integrating forces from all services of the UNSC armed forces. The entire formation, on the battalion scale, was a fully independent special warfare unit that was a three-star command, directed by a Vice Admiral of the UNSC Navy.

Formally known as "SPARTAN Detachment IV", the Myrmidon Detachment was officially subordinated under the UNSC Naval Special Warfare Command (NAVSPECWARCOM) and the UNSC Progressive Warfare Command (PROGWARCOM). The detachment was a member of UNSC Special Warfare Group SPARTAN, reflecting the heritage of the Myrmidons from their ancestral SPARTAN precedessors.

Casus genesis
The causation of the formation of the Myrmidons, their casus genesis, lay simply in the state of galactic affairs.

At the time of the nucleation and formation of the Myrmidons, it was the late 2570s — in the nearly three decades that had passed since 2552 and the closure of the Human-Covenant War, the state of UNSC and mankind had substantially changed after the Great War. Although the UNSC's military forces would continue to resume their force projection during the Vector Era (2560s—2570s), no longer were galactic affairs dependent on military strength.

By the 2570s, the truce between the UNSC and the reformed Covenant was strong, and the two galactic superpowers were bound together by cords of fealty, with strong political and commercial collaboration between the two massive governments. The threat to the UNSC was no longer posed by the Covenant; it was now internal, with domestic threats at home consisting of organized rebel movements and freelancer pirates and mercenaries operating on the Outer Rim.

Kimberly Ivy Blackburn's actions during the Vector Era as an augmented ONI field operative had demonstrated that small, highly-trained, and augmented special forces teams were an ideal solution to the domestic threats that plagued the UNSC and the Covenant in the 2570s. The massive armies of the UNSC Marine Corps and the UNSC Army were simply unequipped to fight intense guerilla wars against rebels and insurgents. Instead, UNSC special forces, highly-trained operatives, would be required for these elite counterinsurgency and counterterrorism activities.

Organization
The Myrmidon Program has a highly atypical command structure and internal organization. One of the major design philosophies of the Myrmidons was counterterrorism; the usage of a small number of highly-trained elite light infantry for highly-intensive counterterror and counterinsurgency operations.

Thus, the Myrmidon Program as of 2590 maintained only one company of infantry, numbering approximately one hundred strong. While this was an extremely small number of operators for any conventional special forces group, it was in accordance with the UNSC's need for a covert and specialized counterterrorism task force.

The ideation of the Myrmidons began with Kawika Son and Beah Schore, who both drew heavily from the success of Kimberly Ivy Blackburn, who indeed served as the proof of concept for the Myrmidon Program. Dr. Schore would only participate in the planning and initiation of the Myrmidons, his lack of military experience and his pacifistic ideals making him unable to participate in the active military mobilization of the Myrmidons. Son would be heavily involved in the creation, training, and the mobilization of the Myrmidons; this would earn him a senior position within the Myrmidon command structure.

Command Detachment
The position of Senior Commander, Myrmidon Detachment was traditionally held by a three-star Vice Admiral ( O-9 ). The detachment's senior commander was responsible for the training, oversight, direction, and operation of the entire Myrmidon unit as a whole, including its command, mobility, and support elements, and would be a member of the Headquarters & Headquarters Company (HHC) of the Myrmidons. The remainder of the HHC section was primarily comprised with the primary staff officers and their staffs, along with the staff officers of the support and auxiliary elements.

The first commander of the Myrmidon Detachment was Vice Admiral Kawika Son, Commander-in-Chief, UNSC Naval Special Warfare Command and a flag officer of the UNSC Navy. Son would begin his tenure as the Myrmidon unit's commander in 2578 as a two-star Rear Admiral, and would relinquish his command in 2600, several years after the closure of the devastating Beyond Veil's Azure crisis.

Mobility Detachment
The actual Myrmidon infantry company proper, known as the "mobility detachment", was approximately one hundred Myrmidons strong, and was responsible for prosecution of the unit's special warfare missions in the field.

The mobility detachment would be commanded by a Navy Captain ( CAPT, O-6 ), the company commander, and a Master Chief Petty Officer ( MCPO, E-9 ), who would serve as unit's senior enlisted NCO.

The remainder of the hundred-odd company was divided into four operational squadrons, Myrmidon Squadron ALPHA ("A"), Myrmidon Squadron BRAVO ("B"), Myrmidon Squadron CHARLIE ("C"), and Myrmidon Squadron DELTA ("D"). Each squadron was comprised of between twenty to thirty operators. The operational squadron was the fundamental deployment unit of the Myrmidons; typically, Myrmidons units were deployed to their respective theater of operations in the squadron-size formation.

Each operational squadron was under the leadership of a Navy Commander ( CMDR, O-5 ) and the squadron's senior enlisted, a Chief Petty Officer ( CPO, E-7 ). While the O-5 would serve as the squadron's commanding officer (CO) and the E-7 would serve as the squadron chief, the two were augmented by a squadron executive officer (XO), typically a Navy Lieutenant ( LT, O-3 ), and a squadron operations officer, typically a Lieutenant, Jr. Grade ( LTJG, O-2 ). The remaining fifteen to twenty-five operators were generally enlisted, special warfare specialists between the ranks of Petty Officer Third Class ( PO3, E-4 ) and Petty Officer First Class ( PO1, E-6 ), although there were a few exceptions.

Beneath the squadron-level formation, their hierarchical organization was not formally defined; instead, sub-squadron units were formed to meet mission requirements. While the majority of missions required either individual Myrmidons solo or a Myrmidon fire team (two-three operators), larger missions employed Myrmidon squads (four-six operators) or whole Myrmidon troops (eight-twelve operators).

A single operation, no matter on what scale, almost never could employ an entire squadron in the field — however, regular squadron-integration exercises were continually scheduled so that the entire squadron could perform as a cohesive warfighting unit, should massive open warfare arise.

All four Myrmidon squadrons were "direct action" capable, that is, that they fulfilled elite counterterrorism and counterinsurgency roles within the UNSC Special Operations Command, practicing even advanced special operations such as in extremis hostage rescue. However, all squadrons carried a secondary certification to further augment the infantry company as a whole. Myrmidon Squadron ALPHA ("A") and Myrmidon Squadron BRAVO ("B") was specially certified for heavy assault, Myrmidon Squadron CHARLIE ("C") was specially certified for dedicated reconnaissance roles, and Myrmidon Squadron DELTA ("D") was specially certified for covert action.

By 2594, Captain Raphael-M064 would serve as Commander, Myrmidon Mobility Detachment.

Support Detachment
The Myrmidon Support Detachment was an integral component of the Myrmidon Detachment, typically commanded by a Marine Corps Colonel ( COL, O-6 ).

The Myrmidon operators were extensively supported on all levels; the individual level, the team level, the squadron level, and the company level. The unit, with its high operations tempo (OPTEMPO), invariably required extensive auxiliary support to continue sustained operations. The Support Detachment was comprised of a Special Operations Air Wing, a Logistical Detachment, an Intelligence Detachment, a Training Detachment, a Communications Detachment, and a Medical Detachment.

The Special Operations Air Wing (SOAW) was responsible for operating attack and transport aviation assets in support of the Myrmidons, and was comprised of elite pilots, technicians, and ground crews from the UNSC Army's Reconnaissance Aviation Expeditionary Force (RAVEN) and also elite UNSC Navy squadrons. The Air Wing was directed by a Navy Captain ( CAPT, O-6 ) from the naval starfighter community.

The Logistical Detachment was responsible for the continued resupply and rearmament of the Myrmidons, and was integral to the sustained deployment of the Myrmidons across the myriad battlefields of the Milky Way Galaxy; it was commanded by a Marine Corps Lieutenant Colonel ( LTCOL, O-5 ).

The Myrmidon unit operated its own independent Intelligence Detachment; on most operations, the Myrmidons received extensive intelligence support. The Myrmidon Intelligence Detachment was strongly affiliated with the UNSC Office of Naval Intelligence, with high-confidence ONI intelligence supporting most Myrmidon field actions. The intelligence section was led by an ONI Commander ( CMDR, O-5 ).

The Myrmidon Training Detachment, based on Asphodel Meadows, was commanded by a Navy Commander ( CMDR, O-5 ). Lieutenant Commander Simon-G294 would serve as the Executive Officer of the Training Detachment during the training of the Myrmidons on Asphodel Meadows in the 2580s.

The Myrmidon Communications Detachment, responsible for long-range cohesive integration of the Myrmidons on a galactic scale as well as fielding short-range planetary and regional communications for Myrmidon field units, was commanded by a Marine Corps Major ( MAJ, O-4 ).

The Myrmidons also operated their own independent clinical unit, the Medical Detachment, which was affiliated with the UNSC Medical Corps and was directed by a Navy Lieutenant Commander ( LCDR, O-4 ).

Augmentations
"We took twenty years to step back, rethink everything. To change all the augmentations from biological to small-molecule chemical compounds, with augmentations specifically tailored to each child. The entire Myrmidon objectives, core fundamentals, all different. It’s a new world. New SPARTANs for a changing time."

- Rear Admiral Kawika Son, 2578

The Myrmidon augmentation philosophy was highly nestled with an advanced understanding of human developmental biology and chemical biology.

An extensive knowledge of mammalian and human developmental biology and stem cell biology allowed for the manipulations of the in utero human embryo, allowing for extensive modifications of the child soldiers prior to birth.

A chemical biology approach was employed for the augmentation regiment, utilizing small-molecule probes to specifically perturb specific biological targets to produce defined phenotypic effects. The usage of small-molecule chemical compounds opposed to biological agents (i.e. peptides or recombinant vectors) maximized the safety of Myrmidon augmentation as well as its reproducibility from human to human. Computational modeling of chemical systems was substantially simpler than modeling of biological factors, which were invariably multiplex, simplifying modeling of chemical modifications of each human subject.

The Myrmidon philosophy, championed by the chemical biologist Beah Schore, advocated the usage of small-molecule chemical compounds as specific perturbers of human biology at the embryonic, postnatal, and adult stages of life. Chemical agonists and inhibitors of biological targets were used to provide quantifiable and dose-responsive control over human physiology and psychology with defined desired phenotypic effects and defined off-target side effects.

Manipulation of the human embryo
Chemical augmentation of Myrmidons began at the embryonic stage, with in utero catherization of pregnant women to perfuse developing human embryos with small-molecule compounds to elicit specific effects on human developmental biology.

Phase I: Expansion of pluripotent stem cells
Firstly, compounds were employed to inhibit the maturation of the human pluripotent inner cell mass (ICM) to the epiblast, maintaining the "ground state" pluripotency of authentic pluripotent cells in the human inner cell mass. This blockade of embryonic maturation allowed for the continual self-renewal and expansion of human embryonic stem (hES) cells, enlarging the pluripotent progenitor pool and allowing for increased numbers of differentiated cells to be formed in embryonic and adult life, increasing mean body size and organ mass.

In order to employ chemical probes to blockade pluripotent stem cell differentiation and maturation, Beah Schore composed a collection of compounds known to either enhance embryonic stem cell self-renewal or to specifically block the differentiation of embryonic stem cells to certain lineages.

Finally, ten small-molecule compounds were chosen for final employment.

An Activin receptor and Nodal receptor inhibitor, A-83-01 ("A8"), was employed to block stem cell differentiation to the definitive endoderm. A bone morphogenetic protein receptor (BMPR) inhibitor, Dorsomorphin ("DM"), was employed to block stem cell differentiation to the mesodermal lineage. A fibroblast growth factor receptor (FGFR) inhibitor, SU5402 ("S5") and an extracellular signal-regulated kinase (ERK) inhibitor, PD184352 ("P1"), were employed to block stem cell differentiation to both the neuroectodermal and mesodermal lineages. Cells that managed to escape the chemical blockade and begin differentiation were rapidly de-differentiated by a mitogen-activated protein kinase (MAPK) and a nonmuscle myosin II heavy chain inhibitor, Reversine ("RV").

Overexpression of Nanog, a key member of the pluripotent transcriptome, has been shown to render stem cells refractory to differentiation, whereas deficiency of Nanog (Nanog-/-) has been shown to render pluripotent cells towards differentiation to multiple lineages, including the primitive endoderm. Because β-catenin and canonical Wnt signaling has been shown to increase Nanog expression, a glycogen synthase kinase 3 (GSK3) inhibitor, CHIR99021 ("C9"), was employed to inhibit the global differentiation of pluripotent stem cells.

A p160-Rho-associated coiled-coil kinase (ROCK) inhibitor, Y-27632 ("Y2"), was employed to inhibit the apoptosis of pluripotent stem cells and to enhance their survival.

Finally, three final compounds were chosen to specifically induce the self-renewal of stem cells. These included a Ras GTPase-activating protein (RasGAP) and an extracellular signal-regulated kinase (ERK) inhibitor, Pluripotin ("SC"), and two natural products with uncharacterized biological targets, Theanine ("TN") and Flurbiprofen ("FP").

Thus, in conclusion, combinatorially, these ten compounds potently blocked the maturation of the inner cell mass (ICM) and the loss of pluripotency by blockade of differentiation, enhancement of stem cell survival, and enhancement of stem cell self-renewal.

Inhibitors of stem cell differentiation

 * A-83-01: Chemical inhibitor of TGFβ/Activin receptors, specifically the activin receptor (ALK4), the TGF-β receptor (ALK5), and the nodal receptor (ALK7)
 * Chemical Name: 3-(6-Methylpyridin-2-yl)-1-phenylthiocarbamoyl-4-quinolin-4-ylpyrazole
 * Biological Target: ACVR1B (ALK4), TGFβRI (ALK5), ACVR1C (ALK7)
 * Biological Activity: Blockade of embryonic stem (ES) cell differentiation to the definitive endoderm, maintaining the pluripotency of human pluripotent stem cells and expanding the pluripotent progenitor pool
 * Biological Annotation: Activin and Nodal signals of the TGFβ family are responsible for the differentiation of pluripotent stem cells to the definitive endoderm. Suppression of TGFβ signals leads to blockade of endodermal differentiation.


 * Dorsomorphin: Chemical inhibitor of TGFβ/BMP receptors, specifically ActRIA (ALK2), BMPRIA (ALK3), and BMPR1B (ALK6)
 * Chemical Name: 6-(4-(2-(piperidin-1-yl)ethoxy)phenyl)-3-(pyridin-4-yl)pyrazolo[1,5-a]pyrimidine
 * Biological Target: ActRIA (ALK2), BMPRIA (ALK3), and BMPR1B (ALK6)
 * Biological Activity: Blockade of embryonic stem (ES) differentiation to the mesoderm, maintaining the pluripotency of human pluripotent stem cells and expanding the pluripotent progenitor pool
 * Biological Annotation: Dorsomorphin is a specific inhibitor of ALK2, ALK3, and ALK6, serving to block transmission of BMP signals, specifically BMP-2, BMP-4, BMP6, and BMP-7 and subsequent phosphorylation of SMADs. The requirement of BMP signals in gastrulation for mesodermal specification means that suppression of BMP signaling in the pluripotent inner cell mass leads to repression of the mesodermal lineage.


 * SU5402: Chemical inhibitor of fibroblast growth factor receptor 1 (FGFR1)
 * Chemical Name: 3-[(3-(2-carboxyethyl)-4-methylpyrrol-2-yl)methylene]-2-indolinone
 * Biological Target: FGFR1 (Fibroblast Growth Factor Receptor 1)
 * Biological Activity: Blockade of embryonic stem cell (ES) differentiation to the endoderm and mesoderm, maintaining the pluripotency of human pluripotent stem cells and expanding the pluripotent progenitor pool
 * Biological Annotation: Fgfr1 and Fgf4 are extensively implicated in stem cell biology and developmental biology. FGF4, an FGFR1 ligand, activates the ERK pathway in embryonic stem cells and inhibits their self-renewal, instead inducing differentiation to the mesodermal and endodermal lineages. Blockade of FGFR1 by SU5402 leads to repression of differentiation-inducing FGF signaling and reduces the competence of embryonic stem cells to differentiate, instead promoting self-renewal.
 * Structural Mechanism: Competitively binds to the ATP-binding site on FGFR1 protein, inhibiting kinase activity by competing with ATP. Interacts with FGFR1 trough three separate intermolecular interactions with the kinase domain in a hydrophobic haven, and demonstrates even electron distribution.


 * PD184352: Chemical inhibitor of the MAPK/ERK pathway
 * Chemical Name: 2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one)
 * Biological Target: Mitogen-activated protein kinase kinase (MKK1)
 * Biological Activity: Blockade of embryonic stem cell (ES) differentiation to the endoderm and mesoderm, maintaining the pluripotency of human pluripotent stem cells and expanding the pluripotent progenitor pool
 * Biological Annotation: ERK is phosphorylated upon FGF4 signaling, triggering lineage commitment of embryonic stem cells, and phospho-ERK is indeed required for endodermal or mesodermal differentiation of embryonic stem cells. Inhibition of the MAPK/ERK pathway with PD184352 leads to repression of the autoinductive FGF4 signal, encouraging pluripotency and embryonic stem cell self-renewal.


 * CHIR99021: Chemical inhibitor of GSK3β, activator of canonical Wnt signaling and Nanog expression
 * Chemical Name: 6-(2-(4-(2,4-dichlorophenyl)-5-(4-methyl-1H-imidazol-2-yl)pyrimidin-2-ylamino)ethylamino)nicotinonitrile
 * Biological Target: Glycogen synthase kinase 3 (GSK3α/β), IC50 = 6.7 nM
 * Biological Activity: Globally blocks pluripotent stem cell differentiation to all lineages, leading to the maintenance of pluripotency of human pluripotent stem cells and expanding the pluripotent progenitor pool
 * Biological Annotation: GSK3β is a biological inhibitor of Wnt signaling, and Wnt signaling is implicated in stem cell self-renewal, controlling the embryonic stem cell transcriptome and cell cycle. The role of Wnt signaling in stem cell self-renewal is believed to be through activation of Nanog transcription, and Nanog is a core member of the pluripotency transcriptome, actively suppressing differentiation and safeguarding against loss of pluripotency. GSK3 inhibition and Wnt signaling has been shown to blockade stem cell differentiation and lead to embryonic stem cell self-renewal.


 * Reversine: Polypharmacological inhibitor of multiple kinases and receptors
 * Chemical Name: 2-(4-morpholinoanilino)-N6-cyclohexyladenine
 * Biological Target: Aurora kinase A, Aurora kinase B, Adenosine receptor A3, MEK1, and Myosin II Heavy Chain
 * Biological Activity: De-differentiates differentiating cells, leading to reprogramming of differentiated cells to authentic pluripotent stem cells and maintenance of the pluripotent progenitor pool through indirect inhibition of differentiation
 * Biological Annotation: Reversine has been shown to de-differentiate myoblasts to a putative multipotent mesenchymal stem cell (MSC)-like intermediate, relaxing lineage specificity and leading to ectopic expression of mesodermal and neuroectodermal transcripts.

Inhibitors of stem cell apoptosis

 * Y-27632: Chemical inhibitor of p160-Rho-associated coiled-coil kinase (ROCK)
 * Chemical Name: (+)-(R)-trans-4-(1-aminoethyl)-N-(4-pyridyl)cyclohexanecarboxamide
 * Biological Target: p160-Rho-associated coiled-coil kinase (ROCK)
 * Biological Activity: Blocks apoptosis of cells of the pluripotent inner cell mass, leading to increased numbers of pluripotent progenitors
 * Biological Annotation: ROCK family kinases are responsible for cell cycle regulation and control of apoptosis. Blockade of ROCK signaling through Y-27632 has been shown to improve the survival of dissociated human embryonic stem cells, putatively through the inhibition of chemically-induced apoptosis. Y-27632 is believed to play a similar role in enhancement of the survival of pluripotent human inner cell mass.

Enhancers of stem cell self-renewal

 * Pluripotin: Polypharmacological inhibitor of both RasGAP and ERK1/2
 * Chemical Name: N-(3-(7-(1,3-dimethyl-1H-pyrazol-5-ylamino)-1-methyl-2-oxo-1,2-dihydropyrimido[4,5-d]pyrimidin-3(4H)-yl)-4-methylphenyl)-3-(trifluoromethyl)benzamide
 * Biological Target: Ras GTPase-activating protein (RasGAP) and extracellular signal-regulated kinase (ERK)
 * Biological Activity: Sustains self-renewal of embryonic stem cells, leading to increased numbers of pluripotent progenitors
 * Biological Annotation: Murine embryonic stem cells spontaneously differentiate, and require both leukemia inhibitory factor (LIF) and murine embryonic fibroblast (MEF) feeder layers to sustain self-renewal. Pluripotin replaces the dual requirement for LIF and feeders, and stem cells cultured in the presence of pluripotin maintain their pluripotency and can be expanded indefinitely in culture in chemically-defined conditions.


 * Theanine: Natural product derived from Camellia sinensis and Boletus badius
 * Chemical Name: 2-amino-4-(ethylcarbamoyl)butyric acid
 * Biological Target: Uncharacterized
 * Biological Activity: Sustains self-renewal of the human pluripotent inner cell mass, leading to increased numbers of pluripotent progenitors
 * Biological Annotation: Theanine was identified through a high-throughput screen to maintain short-term pluripotency of human embryonic stem (hES) cells in the absence of FGF2. As theanine has been shown to increase central nervous system (CNS) concentrations of γ-aminobutryic acid (GABA), its role in embryonic stem cell proliferation is contradictory, as it has been shown that autocrine or paracrine GABAergic signnaling in stem cell cultures leads to repression of embryonic stem cell proliferation.


 * Flurbiprofen: Chemical inhibitor of cyclooxygenase 2 (COX-2)
 * Chemical Name: 2-(3-fluoro-4-phenyl-phenyl)propanoic acid
 * Biological Target: Cyclooxygenase 2 (COX-2)
 * Biological Activity: Sustains self-renewal of the human pluripotent inner cell mass, leading to increased numbers of pluripotent progenitors
 * Biological Annotation: Flurbiprofen was identified through a high-throughput screen to maintain short-term pluripotency of human embryonic stem (hES) cells in the absence of FGF2. Although its precise molecular mechanism is unknown, fluribprofen's activity as an anti-inflammatory agent is mediated through inhibition of protein and leukocyte migration, inhibition of prostaglandin synthesis, stabilization of the cell membrane, and activation of mitochondrial ATPase.

Phase II: Chemically-directed differentiation to germ layers
During the first days of embryogenesis, embryonic development was arrested by the ten chemical compounds employed in "Phase I" of the augmentation, producing a vastly-expanded pool of pluripotent progenitors in the human inner cell mass (ICM), increasing the number of embryonic stem cells ready to undergo development, expanding the number of differentiated cells to be possibly developed in development. However, specification of the three primary germ layers (definitive endoderm, mesoderm, and neuroectoderm) was necessary.

Therefore, in the succeeding days, seven small molecules were employed to efficiently differentiate the expanded pluripotent progenitor pool, transitioning them sequentially from the inner cell mass to the patterning epiblast and the primitive streak (mesendoderm), and later, to the three major germ lineages.

Because during the first phase, pluripotent stem cells were potently stimulated to proliferate and self-renew, it was necessary to de-orbit them from their pluripotency program and instead to transition them to a state amenable to differentiation. This was achieved by employing stauprimide ("SP"), an indirect inhibitor of c-myc, therefore decreasing stem cell proliferation and making them receptive to differentiation cues.

Next, either the mesendoderm or the neuroectoderm was established by a simple fate switch; the presence or absence of TGFβ signaling.

Two putative histone deacetylase (HDAC) inhibitors, IDE1 ("I1") and IDE2 ("I2"), were used to indirectly mimic TGFβ/Activin signaling, specifying a mesendodermal fate in a subset of cells, along with the GSK3 inhibitor BIO-Acetoxime ("BA") to stimulate the Wnt pathway, formatively creating the mesendoderm. Cymarin ("CY"), a cardiac glycoside known to induce SOX17 expression in embryonic stem cells, was used ancillarily to specify the definitive endoderm.

The TGFβ/Activin receptor inhibitor SB431542 ("S1") was employed to inhibit Activin signaling in a subset of cells, diverting them from endodermal differentiation and instead specifying the neuroectoderm in the absence of defining signals. This was further confirmed by selegiline ("SE"), a selective MAOA inhibitor previously shown to encourage the development of the neuroectoderm.

Dysregulation of pluripotent stem cell self-renewal

 * Stauprimide: Chemical inhibitor of NME2 and downregulator of c-myc
 * Biological Target: NME2 (Nonmetastatic cells, protein expressed in-2)
 * Biological Activity: Primes pluripotent stem cells for differentiation, enhancing differentiation of the pluripotent inner cell mass to all lineages and increasing the number of differentiated cells produced
 * Biological Annotation: C-myc is a core component of the pluripotency transcriptome, regulating cell proliferation and chromosomal accessibility through chromatin remodeling. Stauprimide was characterized as an NME2 inhibitor, thereby downregulating c-myc expression, thus, stauprimide was found to globally enhance the differentiation efficiency of human (hES) and murine (mES) embryonic stem cells to all lineages, including endodermal, mesodermal, and neuroectodermal, suggesting that it exits pluripotent stem cells from pluripotency and self-renewal and forces them into an activated state that is receptive and sensitized for pan-lineage differentiation.

Chemical differentiation to the mesendoderm

 * BIO-Acetoxime: Chemical inhibitor of glycogen synthase kinase 3 (GSK3)
 * Chemical Name: (2′Z,3′E)-6-Bromoindirubin-3′-acetoxime
 * Biological Target: Glycogen synthase kinase 3 (GSK3)
 * Biological Activity: Differentiates the embryo to the mesendoderm (primitive streak), defining formation of the definitive endoderm and the mesoderm
 * Biological Annotation: BIO-acetoxime is a GSK3 inhibitor, and therefore is an activator of Wnt signaling. Wnt signaling in the developing embryo sequentially specifies the mesendoderm and later, the mesoderm.


 * Cymarin: Chemical inhibitor of the Na+/K+ pump
 * Chemical Name: (3S,5S,8R,10S,13R,14S,17R)-5,14-dihydroxy-3-((2R,4S,5S,6R)-5-hydroxy-4-methoxy-6-methyltetrahydro-2H-pyran-2-yloxy)-13-methyl-17-(5-oxo-2,5-dihydrofuran-3-yl)hexadecahydro-1H-cyclopenta[a]phenanthrene-10-carbaldehyde
 * Biological Target: Na+/K+ pump
 * Biological Activity: Differentiates the embryo to the definitive endoderm
 * Biological Annotation: Molecular mechanism of action unknown


 * IDE1: Putative chemical inhibitor of histone deacetylases (HDAC)
 * Chemical Name: 2-[(6-carboxyl-hexanoyl)-hydrazonomethyl]-benzoic acid
 * Biological Target: Chemically-biased to inhibit histone deacetylases (HDAC)
 * Biological Activity: Differentiates the embryo to the definitive endoderm
 * Biological Annotation: Differentiates human embryonic stem (hES) and murine embryonic stem (mES) cells to the definitive endoderm with comparable efficiency as Activin A, and indirectly activates TGFβ/Activin signaling.


 * IDE2: Putative chemical inhibitor of histone deacetylases (HDAC)
 * Chemical Name: 7-(2-cyclopentylidenehydrazino)-7-oxohepatanoic acid
 * Biological Target: Chemically-biased to inhibit histone deacetylases (HDAC)
 * Biological Activity: Differentiates the embryo to the definitive endoderm
 * Biological Annotation: Differentiates human embryonic stem (hES) and murine embryonic stem (mES) cells to the definitive endoderm with comparable efficiency as Activin A, and indirectly activates TGFβ/Activin signaling.

Chemical differentiation to the neuroectoderm

 * Selegiline: Chemical inhibitor of monoamine oxidase B (MAOB)
 * Chemical Name: (R)-N-methyl-N-(1-phenylpropan-2-yl)prop-2-yn-1-amine
 * Biological Target: Monoamine oxidase B (MAOB)
 * Biological Activity: Differentiates the embryo to the neuroectoderm
 * Biological Annotation: Molecular mechanisms unknown


 * SB431542: Chemical inhibitor of TGFβ/Activin receptors, specifically the activin receptor (ALK4), the TGF-β receptor (ALK5), and the nodal receptor (ALK7)
 * Chemical Name: 4-(5-Benzol[1,3]dioxol-5-yl-4-pyrldin-2-yl-1H-imidazol-2-yl)-benzamide
 * Biological Target: ACVR1B (ALK4), TGFβRI (ALK5), ACVR1C (ALK7)
 * Biological Activity: Differentates the embryo to the neuroectoderm
 * Biological Annotation: In development, a variety of signals of the TGFβ/Activin, TGFβ/BMP, FGF, and Wnt familes act during gastrulation to specify the mesoderm and endoderm. However, an absence of these signals leads instead to the specification of the neuroectoderm — indeed, the neuroectodermal domain is expanded by ectopic blockade of BMP or TGFβ. Suppression of TGFβ/Activin signaling by SB431542 represses endodermal differentiation cues and aides in differentiation to the neuroectoderm.

Phase III: Chemically-directed multipotent stem cell specification
During the prior phases of the embryonic Myrmidon augmentation, the pluripotent inner cell was first expanded, then directed to differentiate into the three major germ lineages. Subsequently, during "Phase III" of the augmentation, multipotent stem cells would be specified from these germ lineages, leading to substantially enhanced numbers of the differentiated cells generated from those multipotent stem cells.

From the definitive endoderm, multipotent pancreatic progenitors were specified by activation of protein kinase C (PKC) signaling. Treatment with a PKC agonist, (—)-Indolactam V ("IV"), would substantially increase the number of pancreatic progenitors specified.

From the mesoderm, both cardiovascular stem cells and haematopoietic stem cells would be specifically induced, contributing to increased heart mass and increased haematopoietic cells, respectively.

Cardiovascular progenitors in development are both pre-specified and self-renewed by Wnt/β-catenin signaling, therefore the GSK3 inhibitor SB-216763 ("S2") was employed to activate Wnt signaling and to substantially increase the number of multipotent cardiovascular stem cells generated.

Haematopoietic stem cells are embryonically specified and renewed by the combined cyclooxgenase (COX)—prostaglandin pathway, and therefore, a leukotriene D4 receptor antagonist, LY 171883 ("L1"), was employed to significantly increase the number of developmental haematopoietic stem cells.

Cardiovascular stem cell specification

 * SB-216763: Chemical inhibitor of glycogen synthase kinase (GSK3)
 * Chemical Name: 3-(2,4-Dichlorophenyl)-4-(1-methyl-1H-indol-3-yl)-1H-pyr role-2,5-dione
 * Biological Target: Glycogen synthase 3 (GSK3), IC50 = 34.3 nM
 * Biological Activity: Leads to greatly increased numbers of embryonic cardiovascular progenitors (MICPs), leading to highly increased numbers of cardiac muscle, smooth muscle, and endothelial vasculature
 * Biological Annotation: Specification and self-renewal of cardiovascular progenitors are controlled by the Wnt/β-catenin signaling pathway, and inhibition of GSK3 by SB-216763 leads to Wnt pathway activation and subsequent increase in pre-specification and self-renewal of human cardiovascular progenitors.

Haematopoietic stem cell specification

 * LY 171883: Chemical inhibitor of the leukotriene D4 receptor
 * Chemical Name: 1-[2-Hydroxy-3-propyl-4-[4-(1H-tetrazol-5-yl)butoxy]phenyl]ethanone
 * Biological Target: Leukotriene D4 receptor
 * Biological Activity: Leads to greatly increased numbers of haematopoietic stem cells during development
 * Biological Annotation: The linked cyclooxygenase (COX) and prostaglandin pathways have been shown to be both necessary and integral in the developmental specification and self-renewal of embryonic haematopoietic stem cells. Modulation of prostaglandin signaling by LY 171883 leads to a marked increase in the number of haematopoietic stem cells.

Pancreatic progenitor specification

 * (—)-Indolactam V: Chemical agonist of protein kinase C (PKC)
 * Biological Target: Protein kinase C (PKC)
 * Biological Activity: Substantially increases the number of multipotent pancreatic progenitors and the number of downstream endocrine β-cells produced
 * Biological Annotation: PKC signaling appears to necessary for either the induction or expansion of pancreatic progenitors, and PKC inhibitors severely depress the numbers of pancreatic progenitors. Conversely, PKC activation by (—)-Indolactam V causes a substantial increase in the number of human pancreatic progenitors. (—)-Indolactam V directly specifies the multipotent embryonic pancreatic domain from the definitive endoderm at the expense of hepatic specification, and does not increase the efficiency of initial allocation to the definitive endoderm.

Differentiation to neurons

 * Tianeptine: Chemical activator of the serotonin transporter
 * Chemical Name: 7-(3-Chloro-6-methyl-6,11-dihydrodibenzo[c,f][1,2]thiazepin-11-ylamino)heptanoic acid S,S-dioxide
 * Biological Target: Serotonin transporter (SERT)
 * Biological Activity: Enhances visual and tactile sensation
 * Biological Annotation: Genetic deletion of MAOA leads to substantially elevated serotonin levels and disorganization of the visual and somatosensory cortices, leading to severe visual and somatosensory impairment. Tianeptine has the reverse effect, reducing serotonin levels by activating the serotonin transporter, leading to enhanced development of the visual and somatosensory cortices and enhanced sensation.


 * L-AP4: Chemical agonist of group III metabotropic glutamate receptors (mGluR)
 * Chemical Name: L-(+)-2-Amino-4-phosphonobutyric acid
 * Biological Target: Group III metabotropic glutamate receptors (mGluRs)
 * Biological Activity: Increases the neurons developed during development
 * Biological Annotation: Activation of group III metabotropic glutamate receptors potently differentiates neural stem cells to neurons, and improves neuronal survival. Specifically, this effect appears to be mediated through mGluR4 — mGluR4 activity inhibits the proliferation of neurospheres and induces neurogenic commitment.

Differentiation to the pancreas

 * All-trans retinoic acid: Chemical activator and endogenous ligand for the retinoic acid receptors (RARs)
 * Chemical Name: (2E,4E,6E,8E)-3,7-dimethyl-9-(2,6,6-trimethylcyclohexen-1-yl)nona-2,4,6,8-tetraenoic acid
 * Biological Target: RARα ("Retinoic acid receptor alpha"), RARβ ("Retinoic acid receptor beta"), and RARγ ("Retinoic acid receptor gamma")
 * Biological Activity: Creates an enlarged pancreas with especially high numbers of endocrine β-cells
 * Biological Annotation: Retinoid signaling plays an integral role in pancreatic development.  Retinoid signaling is integral for development of the dorsal endoderm and for the formation of the pancreas, and it has been shown that not only does retinoic acid signaling specify the pancreas, but that retinoic acid expands pancreatic endocrine progenitors and greatly increases the number of differentiated pancreatic endocrine cell types formed  , also acting to directly specify insulin-secreting β-cells.


 * Trichostatin A: Chemical inhibitor of Class I and Class II histone deacetylases (HDACs)
 * Chemical Name: R-(E,E)]-7-[4-(Dimethylamino)phenyl]-N-hydroxy-4,6-dimethyl-7-oxo-2,4-heptadienamide
 * Biological Target: Class I and Class II histone deacetylases (HDACs)
 * Biological Activity: Creates especially high numbers of pancreatic endocrine cells, especially insulin-secreting β-cells
 * Biological Annotation: Histone deacetylases are downregulated during pancreatic development, suggesting that their repression is permissive to pancreatic differentiation. Histone deacetylase inhibition leads to promotion of pro-endocrine progenitors at the expense of endocrine differentiation, and trichostatin A has been shown to especially enhance the formation of insulin-secreting β-cells and somatostatin-secreting δ-cells.

Differentiation to the lungs

 * PK115-584: Chemical inhibitor of the Tcf4/β-catenin interaction
 * Chemical Name: 1-[3,10-dihydroxy-12-[2-(4-hydroxyphenoxy)carbonyloxypropyl]-2,6,7, 11-tetramethoxy-4,9-dioxoperylen-1-yl]propan-2-yl benzoate
 * Biological Target: Tcf4/β-catenin, protein kinase C (PKC), and myosin light chain kinase (MLCK)
 * Biological Activity: Increased lung size
 * Biological Annotation: Wnt5a-/- mice demonstrate increased embryonic lung epithelium and mesenchyme proliferation, resulting in expansion of the distal lung and increased lung size. This phenotype was mimicked by PK115-584, which is a promiscuous inhibitor of the Wnt signaling pathway that acts by inhibiting the Tcf4/β-catenin interaction.


 * Compound E: Chemical inhibitor of the γ-secretase complex
 * Chemical Name: (S)-2-(2-(3,5-difluorophenyl)acetamido)-N-((S)-1-methyl-2-oxo-5-phenyl-2,3-dihydro-1H-benzo[e][1,4]diazepin-3-yl)propanamide
 * Biological Target: Presenilin-1 (PS1)
 * Biological Activity: Increased aveolar size and volume
 * Biological Annotation: Notch signaling is influential in lung development, arresting distal lung progenitors before they can commit to an aveolar differentiation program, serving to inhibit aveolar development and differentiation. Conversely, Notch inhibition by Compound E acted instead to increase commitment to aveolar differentiation, increasing aveolar size and volume.

Differentiation to the limb mesenchyme

 * LDN-193189: Chemical inhibitor of TGFβ/BMP receptors, specifically ActRIA (ALK2), BMPRIA (ALK3), and BMPR1B (ALK6)
 * Chemical Name: 4-(6-(4-(piperazin-1-yl)phenyl)pyrazolo[1,5-a]pyrimidin-3-yl)quinoline
 * Biological Target: ActRIA (ALK2), BMPRIA (ALK3), and BMPR1B (ALK6)
 * Biological Activity: Increases the size of leg and arms
 * Biological Annotation: During embryogenesis, limb specification and growth is controlled by a highly complex auto-regulatory loop comprised of the genes Grem1, Fgf4, Fgf8, and Shh. Gremlin (Cktsf1b1, Grem1) is an endogenous BMP antagonist that is necessary for proper limb development. Unopposed BMP signaling leads to repression of expression of FGF signals, and blockade of BMP transmission specifically by Gremlin is required for proper induction of Fgf4 and Fgf8 and proper subsequent limb formation by a Fgf-Shh cascade. In the developing mesenchyme, BMP is potently co-repressed by LDN-193189, a synthetic inhibitor of BMP receptors, leading to an expanded domain of BMP-negative cells and expansion of the developing limbs, leading to enlarged legs and arms.

Musculoskeletal

 * A-769662: Chemical activator of 5' adenosine monophosphate-activated protein kinase (AMPK)
 * Chemical Name: 4-hydroxy-3-(2'-hydroxybiphenyl-4-yl)-6-oxo-6,7-dihydrothieno[2,3-b]pyridine-5-carbonitrile
 * Biological Target: 5' adenosine monophosphate-activated protein kinase (AMPK)
 * Biological Activity: Induces 44% increase in physical endurance and 23% increase in exercise capacity in untrained subjects
 * Biological Annotation: AMPK is activated by exercise, and is integral in maintenance of the muscle transcriptome and for oxidative metabolism. On a phenotypic scale, AMPK's molecular mechanisms lead to its integral role in exercise endurance. As a master transcriptional regulator, AMPK regulates transcription of metabolism-associated genes in muscle — pharmacological activation of AMPK leads to induction of a novel transcriptional program in muscle that imparts enhanced oxidative metabolism and endurance in muscle. Pharmacological activation of AMPK by A-769662 results in a substantial increase in physical endurance and physical capacity even without exercise.
 * GW501516: Chemical activator of peroxisome proliferator-activated receptor δ (PPARδ)
 * Chemical Name: 2-(2-methyl-4-((4-methyl-2-(4-(trifluoromethyl)phenyl)thiazol-5-yl)methylthio)phenoxy)acetic acid
 * Biological Target: Peroxisome proliferator-activated receptor δ (PPARδ)
 * Biological Activity: Increases exercise endurance by 68% and exercise capacity by 70% in combination with exercise
 * Biological Annotation: PPARδ is a master transcriptional regulator of skeletal muscle metabolism, and its induction substantially improves exercise endurance. PPARδ appears to increase endurance through three distinct mechanisms: muscular metabolism, mitochondrial biogenesis, and muscle fiber reprogramming. PPARδ expression induces the expression of genes associated with oxidative metabolism and fatty acid uptake, increasing energy uptake and utilization of muscle fibers, and it also induces mitochondrial biogenesis, augumenting this effect by increasing capacity for cellular metabolism. Furthermore, PPARδ interestingly reprograms muscle fibers to type I "slow-twitch" fibers, increasing the muscular capacity for endurance. Therefore, pharmacological activation of PPARδ by GW501516 leads to substantial changes in muscle that combinatorially lead to significant improvements in physical endurance and capacity.


 * Resveratrol: Chemical activator of Sirtuin 1 (SIRT1) and 5' adenosine monophosphate-activated protein kinase (AMPK)
 * Chemical Name: 3,5,4'-trihydroxytrans-stilbene
 * Biological Target: Sirtuin 1 (SIRT1)
 * Biological Activity: Doubles physical endurance during exercise and increases average lifespan by 70%
 * Biological Annotation: Both targets of resveratrol, AMPK and sirtuin, play integral, albeit distinct, roles in general metabolism as well as skeletal muscle physiology. AMPK's roles in skeletal muscle physiology are multifacted — it induces the production of new mitochondria and also enhances fatty acid oxidation (oxidative metabolism) . In contrast, sirtuin appears to instead enhance mitochondrial activity not by sheer content, but rather transcriptional effects that modify mitochondrial metabolism and also reprogramming of muscle fiber type to slow-twitch and longer-endurance fibers. Taken together, pharmacological activation of both AMPK and sirtuin by resveratrol potently enhances muscle physiology, leading to increased endurance and strength by modulation of both muscular metabolism and mitochondrial function. Furthermore, sirtuin is tightly linked to lifespan — through modulation of bodywide metabolism and adipose tissue consumption, resveratrol increases mean lifespan.


 * SRT1720: Chemical activator of Sirtuin 1 (SIRT1)
 * Biological Target: Sirtuin 1 (SIRT1)
 * Biological Activity: Increases physical strength and doubles physical endurance during exercise
 * Biological Annotation: Sirtuin is a critical modulator of bodily metabolism, lifespan, and skeletal muscle physiology. Its roles in lifespan appear to be linked to the fact that sirtuin enhances energy expenditure in metabolic tissues, precipitously decreasing white fat mass, that it stabilizes genomic DNA , and that it improves cell survival and protects against apoptosis. Sirtuin also is a key regulator of muscle physiology — it enhances endurance by reprogramming Type II "fast-twitch" muscle fibers to Type I "slow-twitch" muscle fibers, and augments mitochondrial activity by enhancing glucose metabolism. Pharmacological activation of SIRT1 by SRT1720 therefore leads to substantial improvements in muscular endurance as well as extension of lifespan.


 * NP549: Chemical inhibitor of glycogen synthase kinase 3 (GSK3)
 * Biological Target: Glycogen synthase kinase 3 (GSK3), IC50 ≤ 0.04 nM
 * Biological Activity: Increases muscle mass
 * Biological Annotation: During muscle regeneration, Wnt signaling controls the myogenic specification of CD45+/Sca1+ stem cells and is integral for muscle regeneration, with Wnt blockade severely impairing myogenesis during muscular regeneration. Ectopic Wnt signaling strongly promotes the myogenic dedication of these stem cells. Therefore, potent activation of Wnt signaling by GSK3 inhibition by the ruthenium inhibitor NP549 leads to dramatic muscular specification of CD45+/Sca1+ stem cells and increased myogenesis and muscle mass.


 * T0070907: Chemical inhibitor of peroxisome proliferator-activated receptor γ (PPARγ)
 * Chemical Name: 2-Chloro-5-nitro-N-4-pyridinylbenzamide
 * Biological Target: Peroxisome proliferator-activated receptor γ (PPARγ), IC50 = 1 nM
 * Biological Activity: Converts brown fat into skeletal muscle
 * Biological Annotation: PRDM16 ("PRD1-BF1-RIZ1 homologous domain containing 16") is a transcriptional regulator that controls a bidirectional fate switch between skeletal muscle and brown adipocytes. PRDM16 reprograms skeletal myocytes to a brown adipogenic lineage; conversely, loss of PRDM16 from brown adipocytes leads to their reprogramming into skeletal myocytes, with adoption of a muscle transcriptiome within days. One of PRDM16's indirect targets is PPARγ; PPARγ facilitates adipogenic reprogramming. Therefore, blockade of the PRDM16-PPARγ pathway by the PPARγ antagonist T0070907 leads to direct conversion of brown fat to skeletal muscle, reducing fat mass and increasing muscle mass.

Learning, Memory, and Cognition

 * FPL 64176: Chemical agonist of voltage-gated L-type Ca+2 channels (LTCCs)
 * Chemical Name: 2,5-Dimethyl-4-[2-(phenylmethyl)benzoyl]-1H-pyrrole-3-carboxylic acid methyl ester
 * Biological Target: L-type Ca+2 channels (Cav1.1, Cav1.2, Cav1.3, and Cav1.4)
 * Biological Activity: Enhances learning and memory
 * Biological Annotation: Calcium influx through L-type Ca+2 channels activates calmodulin and a cascade of kinase and transcriptional changes that ultimately lead to synaptic plasticity and long-term potentiation (LTP) as well as putative neural stem cell proliferation. Supporting this, inhibition of L-type Ca+2 channels leads to impairments in spatial memory. Conversely, activation of L-type Ca+2 channels by FPL 64176 potently induces long-term potentiation and enhances learning and memory.


 * (S)-(-)-Sulpiride: Non-selective chemical antagonist of the dopamine D2 and D3 receptors
 * Chemical Name: (S)-(-)-N-[(1-ethylpyrrolidin-2-yl)methyl]-2-methoxy-5-sulfamoylbenzamide
 * Biological Target: Dopamine D1 receptor (Ki = 45 μM), Dopamine D2 receptor (Ki = 15 nM), Dopamine D3 receptor (Ki = 13 nM), Dopamine D4 receptor (Ki = 1 μM), Dopamine D5 receptor (Ki = 77 μM)
 * Biological Activity: Increased memory storage capacity and enhanced learning and memory
 * Biological Annotation: Dopamine signaling, including through the D1, D2, and D3 receptors, inhibits the proliferation of neural stem cells. Blockade of dopamine signaling by (S)-(-)-Sulpiride, conversely, enhances the proliferation of neural stem cells and rescues them from apoptosis, enhancing neurogenesis. Neurogenesis has been implicated to expand memory storage capacity as well as learning and memory.
 * Compound 9: Tentative chemical agonist of N-methyl-D-aspartate (NMDA) metabotropic glutamate receptors (NMDARs)
 * Chemical Name: N-Cyclopropyl-5-(thiophen-2-yl)isoxazole-3-carboxamide
 * Biological Target: N-methyl-D-aspartic acid (NMDA) receptor (tentative)
 * Biological Activity: Increased memory storage capacity and enhanced learning and memory
 * Biological Annotation: Excitatory transmission potently induces neurogenesis and neural stem cell differentiation, tentatively linking excitatory activity and a requirement for new neurons for memory storage capacity. This sensing of excitatory transmission is primarily mediated through Ca+2-mediated signaling through L-type Ca+2 channels (LTCCs) and NMDA receptors (NMDARs). Compound 9 is a small-molecule mimetic of local excitatory transmission, potently activating Ca+2 influx through NMDA receptors and leading to rapid genome acetylation and neuronal commitment in neural stem cells, potently inducing neurogenesis in vivo. Neurogenesis has been implicated to expand memory storage capacity as well as learning and memory.
 * QS11: Chemical inhibitor of GTPase-activating protein of ADP-ribosylation factor 1 (ARFGAP1)
 * Chemical Name: (S)-2-(9-(biphenyl-4-ylmethyl)-2-(2,3-dihydro-1H-inden-5-yloxy)-9H-purin-6-ylamino)-3-phenylpropan-1-ol
 * Biological Target: GTPase activating protein of ADP-ribosylation factor 1 (ARFGAP1)
 * Biological Activity: Increased memory storage capacity and enhanced learning and memory
 * Biological Annotation: QS11, an ARFGAP1 inhibitor, is a synergist of Wnt signaling — it does directly activate Wnt signaling, but instead synergizes to enhance Wnt signaling in Wnt-active tissues, such as the neurogenic hippocampus. Wnt signaling enhances adult hippocampal neurogenesis, and ectopic Wnt signaling enhances neurogenesis. Therefore, QS11 controls neural stem cell activity and also learning and memory.
 * Neuropathiazol: Chemical activator of hippocampal neurogenesis
 * Chemical Name: ethyl 4-[methyl-(2-phenyl-1,3-thiazol-4-yl)amino]benzoate
 * Biological Target: Unknown
 * Biological Activity: Increases both memory formation and consolidation
 * Biological Annotation: Neuropathiazol induces the differentiation of adult hippocampal neural progenitor cells (HCN) into neurons at the expense of astrocytes, stimulating hippocampal neurogenesis. The adult parahippocampal–hippocampal network is integral in memory, in both formation and consolidation of memories.


 * TWS119: Chemical inhibitor of glycogen synthase kinase 3β (GSK3β)
 * Biological Target: Glycogen synthase kinase 3β (GSK3β), IC50 = 30 nM
 * Biological Activity: Increased memory storage capacity and enhanced learning and memory
 * Biological Annotation: Wnt signaling plays integral roles in stem cell biology during both development and adult life. Surprisingly, TWS119 directs the neuronal differentiation of pluripotent embryonic carcinoma (EC) and embryonic stem (ES) cells, despite the inhibitory role of Wnt signaling in neural differentiation during gastrulation. Promotion of neurogenesis by TWS119 leads to enhancements in both learning and memory.


 * (S)-(-)-Cotinine: Chemical agonist of α3β2 and α6β2 nicotinic acetylcholine receptors (nAChRs)
 * Chemical Name: (S)-1-Methyl-5-(3-pyridinyl)-2-pyrrolidinone
 * Biological Target: α3β2/α6β2 nicotinic acetylcholine receptors (nAChRs)
 * Biological Activity: Enhances working and reference memory, increases attention, and increases neuronal survival
 * Biological Annotation: The cholinergic system is strongly involved in cognition, and activation of cholinergic signaling has been shown to reverse cognitive deficits. Activation of the cholinergic system has been shown to enhance working and reference memory and attention, even in cognitively-impaired subjects, and to improve neuronal survival. (S)-(-)-Cotinine is a nicotine metabolite in humans and is an agonist of specific striatal nicotinic acetylcholine receptors , potentiating cognitive-enhancing effects.


 * O-1783: Chemical inhibitor of the dopamine active transporter (DAT) inhibitor
 * Biological Target: Dopamine active transporter (DAT), IC50 = 17 nM
 * Biological Activity: Enhances decision making, reaction time, planning, memory, attention, and wakefulness
 * Biological Annotation: Cognitive enhancers of the 20th century, such as methylphenidate ("Ritalin") and modafinil, were potent inhibitors of the dopamine active transporter (DAT), potentiating strong cognitive-enhancing effects, whose effects appear in part to be mediated by the catecholaminergic system.  Potentiation of dopaminergic transmission leads to highly beneficial effects in executive function, enhancing decision making , reaction time , memory , and wakefulness . These results are recapitulated by a synthetic oxacyclic derivative of methylphenidate, O-1783, which is as equally potent as its precedessor.

Cardiovascular and Circulatory

 * Hh-Ag1.5: Chemical agonist of the Smoothened (Smo) receptor
 * Chemical Name: 3-chloro-4,7-difluoro-N-(4-methoxy-3-(pyridin-4-yl)benzyl)-N-(4-(methylamino)cyclohexyl)benzo[b]thiophene-2-carboxamide
 * Biological Target: Smoothened (Smo)
 * Biological Activity: Potently induces formation of new blood vessels
 * Biological Annotation: The Hedgehog (Hh) signaling pathway is a morphogen that controls neovascularization in adult tissues. Ectopic Hedgehog stimulation nearly triples capillary density and induces the growth of new large-diameter blood vessels to increase oxygen perfusion of target tissues. This adult neovascularization was recapitulated with Hh-Ag1.5, a potent agonist of Hedgehog signaling.
 * SNAP: Chemical donor of nitric oxide (NO)
 * Chemical Name: (S)-Nitroso-N-acetylpenicillamine
 * Biological Target: Nitric oxide donor, functional mimetic of endogenous nitric oxide synthase (NOS)
 * Biological Activity: Increases blood flow and induces formation of new blood vessels
 * Biological Annotation: Nitric oxide (NO) is a short-range signaling molecule that plays important roles in the hematopoietic and circulatory systems during both adult life and development. In the adult, it induces vasodilation, increasing blood flow, and also induces neovascularization of ischemic tissues. SNAP, a functional agonist of nitric oxide signaling by acting as a stable nitric oxide donor, enhances both blood flow and blood vessel growth through the nitric oxide pathway.


 * 16,16-dimethyl Prostaglandin E2: Eicosanoid DP1 and DP2 receptor agonist
 * Biological Target: Eicosanoid DP1 receptor (PTGDR, "Prostaglandin D2 Receptor") and eicosanoid DP2 receptor (GPR44, "G protein-coupled receptor 44")
 * Biological Activity: Increases oxygen carrying capacity, blood clotting, and immunity
 * Biological Annotation: The cyclooxygenase (COX)-prostaglandin pathway is a central modulator of hematopoietic stem cell formation and proliferation, potently inducing self-renewal of haematopoietic stem cells in the adult. Prostaglandin regulation of haematopoietic stem cells converges on the Wnt/β-catenin pathway. Induction of haematopoietic stem cell proliferation leads to increased formation of haematopoietic lineage cells, increasing oxygen carrying capacity (erythrocytes), clotting (platelets), non-specific immunity (granulocytes, monocytes / macrophages, natural-killer cells), and specific immunity (B lymphocytes and T lymphocytes).

Eyesight and Vision

 * A-443654: Paradoxical chemical activator of Akt/PKB
 * Chemical Name: (S)-1-(5-(3-Methyl-1H-indazol-5-yl)pyridin-3-yloxy)-3-(1H-indol-3-yl)propan-2-amine
 * Biological Target: Akt/PKB (Protein Kinase B)
 * Biological Activity: Improves color vision and high-resolution vision
 * Biological Annotation: Retinitis pigmentosa, an incurable disease of blindness, is caused by a progressive loss of cone photoreceptors because of a loss of survival and growth signals through the mammalian target of rapamycin (mTOR) pathway. Conversely, stimulation of Akt, an upstream modulator of mTOR, by a paradoxical chemical activator of Akt, A-443654, leads to growth of cone photoreceptors and improvements in color vision and high-acuity vision.


 * BPIQ-II: Chemical inhibitor of the epidermal growth factor receptor (EGFR)
 * Chemical Name: 8-[(3-Bromophenyl)amino]-1H-imidazo[4,5-g]-quinazoline
 * Biological Target: Epidermal growth factor receptor (EGFR)
 * Biological Activity: Enhances growth of the optic nerve during adulthood
 * Biological Annotation: EGFR mediates the inhibitory effects of myelin (Nogo-66) and chondroitin sulfate proteoglycans (oligodendrocyte myelin glycoprotein) on axonal regeneration. Pharmacological or genetic inhibition of EGFR promotes neurite outgrowth from a number of cell types, and increases axonal regeneration after damage of the optic nerve, and blockade of EGFR by BPIQ-II leads to increased optic nerve growth and vision.

Regeneration of Organs and Limbs

 * SB-415286: Chemical inhibitor of glycogen synthase kinase (GSK3)
 * Chemical Name: 3-(3-chloro-4-hydroxyphenylamino)-4-(2-nitrophenyl)-1H-pyrrole-2,5-dione
 * Biological Target: Glycogen synthase 3 (GSK3), IC50 = 77.5 nM
 * Biological Activity: Enables regeneration of limbs and organs
 * Biological Annotation: Lower vertebrates are capable of extensive tissue regeneration even after substantial damage, and this process involves genes in the FGF family (Fgf2, Fgf10, and Fgf20) and the Wnt family (Wnt8 and Wnt10). Importantly, FGF2 is capable of even regenerating chicken limb buds, which do not naturally regenerate. Wnt signaling is a highly-conserved master regulator of regeneration, controlling limb regeneration (through regulation of FGF signaling) as well as controlling regeneration of the liver and the hematopoietic system. Therefore, ectopic activation of Wnt signaling by pharmacological inhibition of GSK3 by SB-415286 leads to regeneration of both limbs and organs in advanced vertebrates such as humans.

Body Size and Organ Size

 * G-1: Selective chemical agonist of G Protein-Coupled Receptor 30 (GPR30)
 * Biological Target: G Protein-Coupled Receptor 30 (GPR30)
 * Biological Activity: Increases body size and organ mass
 * Biological Annotation: GPR30 is an alternative receptor for estrogen, and plays substantial roles in adult growth. While estrogen reduces mean body size and height, genetic selection of GPR30 leads to decreased body size and organ mass, indicating that GPR30 is essential for growth and weight ; GPR30's transactivation of the epidermal growth factor receptor (EGFR) pathway may also participate in its growth-enhancing effects. Therefore, selective activation of GPR30 with G-1 leads to increased body size, weight, and organ mass.


 * ZM 336372: Paradoxical chemical activator of Raf1
 * Chemical Name: N-[5-(3-dimethylaminobenzamido)-2-methyIphenyl]-4-hydroxybenzamide
 * Biological Target: Raf1 (V-raf-1 murine leukemia viral oncogene homolog 1, c-Raf)
 * Biological Activity: Increases body size and increased blood vessel formation
 * Biological Annotation: Raf1 is a Ras GTPase-controlled kinase that is the upstream regulator of the classical mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) pathway, a key signaling pathway that controls cell growth and survival. Raf1-/- mice are growth-impaired and have extensive defects in their vasculature ; correspondingly, the major function of Raf1 is believed to be inhibition of apoptosis. Therefore, pharmacological activation of Raf1 by ZM 336372 leads to both increased body size and increased vascularization.

Combat Physiology

 * Batrachotoxin: Chemical activator of Na+ channels

Combat Psychology

 * (R)-(+)-WIN 55212: CB1 and CB2 cannabinoid receptor activator, described by Compton et. al (2002) to have an in vitro biological activity at a Ki of of 62.3 ± 31 nM for human CB1 and a Ki of 3.30 ± 0.40 nM for human CB2 against 0.5 nM [3H]CP 55940
 * JZL184: monoacylglycerol lipase (MAGL) inhibitor that increases 2-arachidonoylglycerol (2-AG) transmission, described by Long et. al (2009) to have nearly-complete inhibitory activity at 1.0 nM
 * Chemical Name: 4-Nitrophenyl 4-(dibenzo[d][1,3]dioxol-5-yl(hydroxy)methyl)piperidine-1-carboxylate
 * Biological Target: Monoacylglycerol lipase (MAGL), IC100 ≈ 0.25 μM


 * BP-554

Nucleation
The Myrmidon Program would formally have its genesis in 2578. Conceptualized by Dr. Beah Schore of the Harvard Stem Cell Institute and Rear Admiral Kawika Son of the UNSC Naval Special Warfare Command, it would be authorized in early 2578 by the UNSC Office of Naval Intelligence, given the highest priority to train and operate the next iteration of SPARTAN child soldiers, the fourth generation of the SPARTAN Program.

Almost immediately, Admiral Son would begin the nucleation of a core cadre of individuals to train the Myrmidons. While Schore's team would begin investigation of the chemical biology necessary to augment the future warriors, Son would authorize Operation: MARSHAL YELLOW on Hekate and Operation: RALLY VIOLET on Bifröst, gathering ex-SPARTANs such as Simon-G294, Cassandra-G006, Apollo ("Agent 2994"), and Artemis ("Agent 2995") to serve as program advisors and dedicated drill instructors (DIs) to teach the future Myrmidons where their predecessors, the SPARTANs, had gone astray.

Birth and Embryonic Augmentation
The birth of the Myrmidons was founded on their precedent, Kimberly Ivy Blackburn; artificial selection of optimal gamete donors and recipients to ensure that the progeny borne would be of unparalleled caliber on a genetic scale. One hundred sperm donors were chosen from decorated members of the UNSC special warfare community and conscientiously-accepting chosen women were artificially inseminated to produce artificial genetic crosses between the most exceptional that mankind had to offer.

Selection of gamete donors was carried out intensively, with extensive bioinformatics and high-throughput genetic sequencing employed to ensure that only the most exceptional humans were selected to be the parents of the future Myrmidons. Gamete donors were selected from a pool of decorated UNSC special warfare veterans of appropriate age, and these primary donors were intensively screened for physical, mental, and genetic fitness by the Myrmidon Program staff. Highly-fit individuals, secondary donors, were further screened with bioinformatics; genetic sequencing was employed to sequence small nucleotide polymorphisms (SNPs) and restriction fragment length polymorphisms (RFLP) to identify individual polymorphisms linked to disease susceptibility and also referenced against polymorphism sequence records obtained from the SPARTAN-Is, SPARTAN-IIs, SPARTAN-IIIs, and Kimberly Ivy Blackburn.

From the secondary pool, tertiary donors were finally selected based on bioinformatic analysis to confirm that they had few to none polymorphisms associated with disease susceptibility and that they had moderate to high homology to the polymorphism arrays of prior SPARTANs. What remained were two hundred-odd highly-fit UNSC special warfare veterans of both sexes; genetic crosses were made utilizing algorithms to calculate fitness post-breeding. These willing donors were matched, and sperm collection and artificial insemination of female hosts was performed.

Several days after artificial insemination and zygote formation, the first phase of chemical augmentation began — while the future Myrmidons were still in the uterus. Prior to implantation, sterile catheters were surgically integrated into the host uteruses, and a cocktail of small molecule compounds were perfused to inhibit the differentiation of the pluripotent inner cell mass (ICM) and to retain pluripotency, expanding the human pluripotent progenitor pool to increase the number of differentiated cells formed in postnatal and adult life. These compounds included inhibitors of differentiation (A-83-01, Dorsomorphin, SU5402, PD184352, Reversine, and CHIR99021), enhancers of embryonic stem cell self-renewal (Pluripotin, Theanine, and Flurbiprofen), and an inhibitor of stem cell apoptosis (Y-27632).

After sufficient expansion of the pluripotent inner cell mass, chemical blockade of differentiation was relieved, and the differentiating embryos underwent the second phase of embryonic augmentation; the embryos now underwent long-term latent chemical perfusion with a compound cocktail that chemically directed the embryonic specification or amplification of multipotent stem cell pools to increase downstream differentiated cell formation. The Hedgehog (Hh) agonist Hh-Ag1.5 and the D2 receptor antagonists Sulpiride or L-741,626 were employed to specify and amplify multipotent neural stem cells (NSCs) in the nervous system, 16,16-Dimethyl Prostaglandin E2 was employed to specify and amplify haematopoietic stem cells (HSCs) in the bone marrow, and a protein kinase C (PKC) inhibitor, (—)-Indolactam V, was employed to specify pancreatic progenitor cells.

By the closure of 2578, all the Myrmidon progeny were successfully borne.

Order of Battle
Current as of the Beyond Veil's Azure Crisis (2594)


 * Myrmidon Headquarters Company (HHC)
 * Commanding Officer: US-O9 insignia.svg.png Vice Admiral Kawika Son, Commander-in-Chief, UNSC Naval Special Warfare Command ( VADM, O-9 )
 * Executive Officer: US-O8 insignia.svg.png Rear Admiral Evelyn Lake ( RADM, O-8 )
 * Chief of Operations: US-O8 insignia.svg.png Rear Admiral Chandler Danial ( RADM, O-8 )
 * Chief of Operations: US-O8 insignia.svg.png Rear Admiral Randall Hayes ( RADM, O-8 )
 * Chief of Intelligence: US-O8 insignia.svg.png Rear Admiral Peter Thoreau ( RADM, O-8 )
 * Deputy Chief of Operations: US-O6 insignia.svg.png Captain Artemis-2995 ( CAPT, O-6 )
 * Deputy Chief of Operations: US-O5 insignia.svg.png Commander Cassidy-G044 (CMDR, O-5)
 * Assistant Chief of Operations: Senior Chief Petty Officer Insignia.png Senior Chief Petty Officer Apollo-2994 (SCPO, E-8)
 * Assistant Chief of Operations: Senior Chief Petty Officer Insignia.png Senior Chief Petty Officer Whitney-G179 (SCPO, E-8)
 * Senior Commissioned Advisor: US-O8 insignia.svg.png Rear Admiral Beah Schore (Ret.)
 * Senior Enlisted Advisor: Master Chief Petty Officer Insignia.png Master Chief Petty Officer Kimberly Ivy Blackburn (Ret.)
 * Myrmidon Mobility Detachment
 * Commanding Officer: US-O6 insignia.svg.png Captain Raphael-M064 ( CAPT, O-6 )
 * Detachment Senior Enlisted: Master Chief Petty Officer Insignia.png Master Chief Petty Officer Karen-M013 ( MCPO, E-9 )
 * Myrmidon Squadron ALPHA (Direct Action / Assault)
 * Commanding Officer: US-O5 insignia.svg.png Commander Caroline-M063 (CMDR, O-5)
 * Squadron Senior Enlisted: CPO (Chief Petty Officer, E-7)
 * Alpha Squadron XO: LT (Lieutenant, O-3)
 * Squadron Operations Officer: LTJG (Lieutenant Jr. Grade, O-2)
 * Myrmidon Squadron BRAVO (Direct Action / Assault)
 * Commanding Officer: US-O5 insignia.svg.png Commander Ashley-M014 (CMDR, O-5)
 * Squadron Senior Enlisted: CPO (Chief Petty Officer, E-7)
 * Bravo Squadron XO: LT (Lieutenant, O-3)
 * Squadron Operations Officer: LTJG (Lieutenant Jr. Grade, O-2)
 * Myrmidon Squadron CHARLIE (Direct Action / Reconnaissance)
 * Commanding Officer: US-O5 insignia.svg.png Commander Everest-M085 (CMDR, O-5)
 * Squadron Chief: Chief Petty Officer Insignia.png Chief Petty Officer Ezekiel-M049 (CPO, E-7)
 * Executive Officer: US-O3 insignia.svg.png Lieutenant Blake-M079 (LT, O-3)
 * Operations Officer: (LTJG, O-2)
 * Myrmidon Team CHARLIE-ONE ("Specter Team") (Close-range assault)
 * US-O5 insignia.svg.png Commander Everest-M085
 * Chief Petty Officer Insignia.png Chief Petty Officer Ezekiel-M049
 * Myrmidon Team CHARLIE-FOUR ("Phantom Team") (Sniper / Reconnaissance)
 * US-O3 insignia.svg.png Lieutenant Blake-M079
 * Chief Petty Officer Insignia.png Chief Petty Officer Alexis-M050
 * Myrmidon Squadron DELTA (Direct Action / Covert Action)
 * Commanding Officer: US-O5 insignia.svg.png Commander Florian-M021 (CMDR, O-5)
 * Squadron Chief: Chief Petty Officer Insignia.png Chief Petty Officer Eve-M005 (CPO, E-7)
 * Executive Officer: LT (Lieutenant, O-3)
 * Operations Officer: US-OF1A.svg.png Lieutenant Jr. Grade Bjorn-M047 (LTJG, O-2)
 * Myrmidon Team DELTA-ONE ("Valkyrie Team") (Close-range assault)
 * US-O5 insignia.svg.png Commander Florian-M021 (CMDR, O-5)
 * Chief Petty Officer Insignia.png Chief Petty Officer Eve-M005 (CPO, E-7)
 * US-OF1A.svg.png Lieutenant Jr. Grade Bjorn-M047 (LTJG, O-2)
 * Petty Officer 2nd Class Daphne-M097 (PO2, E-5)
 * Myrmidon Team DELTA-SEVEN ("Loki Team") (Sniper / Reconnaissance)
 * Petty Officer 1st Class Alyssa-M028 (PO1, E-6)
 * Petty Officer 2nd Class Gordon-M055 (PO2, E-5)
 * Petty Officer 2nd Class Daphne-M097 (PO2, E-5)
 * Myrmidon Team DELTA-SEVEN ("Loki Team") (Sniper / Reconnaissance)
 * Petty Officer 1st Class Alyssa-M028 (PO1, E-6)
 * Petty Officer 2nd Class Gordon-M055 (PO2, E-5)
 * Myrmidon Support Detachment
 * Commanding Officer:
 * Commander, Aviation Wing
 * Commander, Logistical Detachment
 * Commander, Intelligence Detachment
 * Myrmidon Training Detachment
 * Commanding Officer, Training Detachment: US-O5 insignia.svg.png Commander Cassidy-G044 (CMDR, O-5)
 * Executive Officer, Training Detachment: US-O4 insignia.svg.png Lieutenant Commander Joshua-G024 (LCDR, O-4)
 * Executive Officer, Training Detachment: US-O4 insignia.svg.png Lieutenant Commander Daniels-G288 (LCDR, O-4)
 * Executive Officer, Training Detachment: US-O4 insignia.svg.png Lieutenant Commander Simon-G294 (LCDR, O-4)
 * Assistant Officer-in-Charge, Training Detachment: US-O3 insignia.svg.png Lieutenant Amy-G094 (LT, O-3)
 * Special Warfare School, Primary Trainer: Senior Chief Petty Officer Insignia.png Senior Chief Petty Officer Whitney-G179 (SCPO, E-8)
 * Special Warfare School, Primary Trainer: Senior Chief Petty Officer Insignia.png Senior Chief Petty Officer Jennifer-G272 (SCPO, E-8)
 * Sniper School, Primary Trainer: US-OF1A.svg.png Lieutenant Jr. Grade Maria-G173 (LTJG, O-2)
 * Sniper School, Primary Trainer: Chief Petty Officer Insignia.png Chief Petty Officer Angelina-G152 (CPO, E-7)
 * Demolitions School, Primary Trainer: Chief Petty Officer Insignia.png Chief Petty Officer Kruger-G107 (CPO, E-7)
 * Combat Medicine School, Primary Trainer: US-O3 insignia.svg.png Lieutenant Cassandra-G006 (LT, O-3)
 * Combat Medicine School, Primary Trainer: Chief Petty Officer Insignia.png Chief Petty Officer Rachael-G025 (CPO, E-7)
 * Commander, Communications Detachment
 * Myrmidon Medical Detachment
 * Executive Officer, Medical Detachment: US-O3 insignia.svg.png Lieutenant Cassandra-G006 (LT, O-3)

Behind the Scenes

 * The Myrmidons are named after the Myrmidons of Greek mythology, another Greek warfighting tribe similar to the Spartans in ancient times.
 * As of June 2009, the Myrmidon Detachment page stands as the second-longest article on Halo Fan Fiction Wikia, discounting roleplays, novels, and lists. The only longer page is Kimberly Ivy Blackburn, also written by RelentlessRecusant, which was the Best Article of the Year in 2008 in the First Annual Halo Fan Fiction Wikia Awards.

Article Contributions
RELENTLESSRECUSANT1, 2 with contributions by Actene2, ODST Joshie2
 * Author affiliations
 * 1Harvard Stem Cell Institute and the Department of Stem Cell & Regenerative Biology, Harvard University
 * 2Halo Fan Fiction Wikia and Halopedia, the Halo Wikia


 * RELENTLESSRECUSANT was the primary author of this article, who conceptualized, researched, wrote, revised, and referenced the article.
 * ACTENE was an ancillary contributor to this article, and provided helpful suggestions for revisions as well as generously contributing characters from Team Jian and the High-Priority Assassination Program to supplement the article.
 * ODST JOSHIE was an ancillary contributor to this article, and generously contributed characters from Team Xiphos to supplement the article.