title: L-arginine stimulates fibroblast proliferation through the GPRC6A-ERK1/2 and PI3K/Akt pathway.
abstract: L-arginine is considered a conditionally essential amino acid and has been shown to enhance wound healing. However, the molecular mechanisms through which arginine stimulates cutaneous wound repair remain unknown. Here, we evaluated the effects of arginine supplementation on fibroblast proliferation, which is a key process required for new tissue formation. We also sought to elucidate the signaling pathways involved in mediating the effects of arginine on fibroblasts by evaluation of extracellular signal-related kinase (ERK) 1/2 activation, which is important for cell growth, survival, and differentiation. Our data demonstrated that addition of 6 mM arginine significantly enhanced fibroblast proliferation, while arginine deprivation increased apoptosis, as observed by enhanced DNA fragmentation. In vitro kinase assays demonstrated that arginine supplementation activated ERK1/2, Akt, PKA and its downstream target, cAMP response element binding protein (CREB). Moreover, knockdown of GPRC6A using siRNA blocked fibroblast proliferation and decreased phosphorylation of ERK1/2, Akt and CREB. The present experiments demonstrated a critical role for the GPRC6A-ERK1/2 and PI3K/Akt signaling pathway in arginine-mediated fibroblast survival. Our findings provide novel mechanistic insights into the positive effects of arginine on wound healing.
authors.affiliation: Department of Plastic Surgery, Osaka University Graduate School of Medicine, Suita-shi, Osaka, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Fujiwara
authors.affiliation: Department of Plastic Surgery, Osaka University Graduate School of Medicine, Suita-shi, Osaka, Japan.
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Kanazawa
authors.affiliation: Department of Plastic Surgery, Osaka University Graduate School of Medicine, Suita-shi, Osaka, Japan.
authors.forename: Ryoko
authors.initials: R
authors.lastname: Ichibori
authors.affiliation: Department of Plastic Surgery, Osaka University Graduate School of Medicine, Suita-shi, Osaka, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Tanigawa
authors.affiliation: Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University, Suita-shi, Osaka, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Magome
authors.affiliation: Department of Research & Development Noevir Co., Ltd. Higashiomi, Shiga, Japan.
authors.forename: Kenta
authors.initials: K
authors.lastname: Shingaki
authors.affiliation: Division of Molecular Brain Science, Research Institute of Traditional Asian Medicine, Kinki University, Osakasayama, Osaka, Japan.
authors.forename: Shingo
authors.initials: S
authors.lastname: Miyata
authors.affiliation: Division of Molecular Brain Science, Research Institute of Traditional Asian Medicine, Kinki University, Osakasayama, Osaka, Japan.
authors.forename: Masaya
authors.initials: M
authors.lastname: Tohyama
authors.affiliation: Department of Plastic Surgery, Osaka University Graduate School of Medicine, Suita-shi, Osaka, Japan.
authors.forename: Ko
authors.initials: K
authors.lastname: Hosokawa
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001120:Arginine / Q000494:pharmacology*; D049109:Cell Proliferation / Q000187:drug effects; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D020405:Dermis / Q000166:cytology; D004789:Enzyme Activation / Q000187:drug effects; D005347:Fibroblasts / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology; D055785:Gene Knockdown Techniques; D006801:Humans; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D041681:NIH 3T3 Cells; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D001120:Arginine; D017362:Cyclic AMP Response Element-Binding Protein; D017868:Cyclic AMP-Dependent Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt; D043562:Receptors, G-Protein-Coupled; C488584:GPRC6A protein, human