title: An ALPHA7 Nicotinic Acetylcholine Receptor Agonist (GTS-21) Promotes C2C12 Myonuclear Accretion in Association with Release of Interleukin-6 (IL-6) and Improves Survival in Burned Mice.
abstract: The role of interleukin-6 (IL-6) in physiological processes and disease is poorly understood. The hypothesis tested in this study was that selective alpha7 acetylcholine receptor (α7AChR) agonist, GTS-21, releases IL-6 in association with myonuclear accretion and enhances insulin signaling in muscle cells, and improves survival of burn injured (BI) mice. The in vitro effects of GTS-21 were determined in C2C12 myoblasts and 7-day differentiated myotubes (myotubes). The in vivo effects of GTS-21 were tested in BI wild-type (WT) and IL-6 knockout (IL6KO) mice. GTS-21 dose-dependently (0 μM, 100 μM, and 200 μM) significantly increased IL-6 levels in myoblasts and myotubes at 6 and 9 h. GTS-21-induced IL-6 release in myotubes was attenuated by methyllycaconitine (α7AChR antagonist), and by Stat-3 or Stat-5 inhibitors. GTS-21 increased MyoD and Pax7 protein expression, myonuclear accretion, and insulin-induced phosphorylation of Akt, GSK-3β, and Glut4 in myotubes. The glucose levels of burned IL6KO mice receiving GTS-21 decreased significantly compared with sham-burn IL6KO mice. Superimposition of BI on IL6KO mice caused 100% mortality; GTS-21 reduced mortality to 75% in the IL6KO mice. The 75% mortality in burned WT mice was reduced to 0% with GTS-21. The in vitro findings suggest that GTS-21-induced IL-6 release from muscle is mediated via α7AChRs upstream of Stat-3 and -5 pathways and is associated with myonuclear accretion, possibly via MyoD and Pax7 expression. GTS-21 in vivo improves survival in burned WT mice and IL6KO mice, suggesting a potential therapeutic application of α7AChR agonists in the treatment of BI.
authors.affiliation: *Department of Anesthesiology, Critical Care and Pain Medicine, Shriners Hospitals for Children, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts †Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, Florida ‡Department of Surgery, Shriners Hospitals for Children, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts.
authors.forename: Mohammed A S
authors.initials: MAS
authors.lastname: Khan
authors.forename: Mohammed F
authors.initials: MF
authors.lastname: Khan
authors.forename: Shizuka
authors.initials: S
authors.lastname: Kashiwagi
authors.forename: William R
authors.initials: WR
authors.lastname: Kem
authors.forename: Shingo
authors.initials: S
authors.lastname: Yasuhara
authors.forename: Masao
authors.initials: M
authors.lastname: Kaneki
authors.forename: Ronald G
authors.initials: RG
authors.lastname: Tompkins
authors.forename: Jeevendra A J
authors.initials: JAJ
authors.lastname: Martyn
mesh_terms: D000818:Animals; D001597:Benzylidene Compounds / Q000494:pharmacology*; D002056:Burns / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D015850:Interleukin-6 / Q000096:biosynthesis* / Q000235:genetics; D051379:Mice; D018345:Mice, Knockout; D018485:Muscle Fibers, Skeletal / Q000378:metabolism* / Q000473:pathology; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism*; D032448:Myoblasts, Skeletal / Q000378:metabolism* / Q000473:pathology; D011725:Pyridines / Q000494:pharmacology*; D064569:alpha7 Nicotinic Acetylcholine Receptor / Q000819:agonists* / Q000235:genetics / Q000378:metabolism
chemical_list: D001597:Benzylidene Compounds; D015850:Interleukin-6; D009124:Muscle Proteins; D011725:Pyridines; D064569:alpha7 Nicotinic Acetylcholine Receptor; C577686:interleukin-6, mouse; C088936:3-(2,4-dimethoxybenzylidene)anabaseine