AIM:To investigate the effect of liraglutide ( LG) on the expression of fibronectin type Ⅲdomain-containing protein 5 (FNDC5) in the C2C12 myotubes.METHODS:The C2C12 mouse myoblast cell line was induced to differentiation.Differentiated cells were stimulated with gradient concentrations (1 ~1000 nmol/L) of LG for different time (0 ~24 h).The effects of LG on the expression of FNDC5 and the activation of adenosine 5'-monophosphate ( AMP)-activated protein kinase ( AMPK) signaling pathway were determined .After pretreated with glucagon-like peptide-1 ( GLP-1 ) receptor antagonist exendin 9-39 , the inhibitor of Ca 2+/calmodulin-dependent protein kinase kinase 2 (CAMKK2), STO609, or the inhibitor of AMPK, Compound C, the LG-induced FNDC5 expression in C2C12 myotubes was examined.The expression of FNDC5 and the activation of AMPK were determined by Western blot .RESULTS: In C2C12 myotubes, LG promoted the expression of FNDC5 in a dose-and time-dependent manner .LG also activated AMPK signaling pathway .These effects of LG were partly abolished by exendin 9-39 , STO609 and Compound C .CONCLUSION:LG promotes the expression of FNDC5 via GLP-1 receptor in the C2C12 myotubes possibly through activation of the CAMKK2/AMPK signaling pathways .

[ ABSTRACT] AIM:To investigate the role of hydrogen sulfide ( H2 S) on impaired wound healing in ob/ob mice and the underlying mechanism.METHODS:The ob/ob mice were randomly divided into 3 groups, including vehicle, in-sulin and NaHS for treatment.C57BL/6 mice were treated with vehicle as control.Full-thickness punch biopsy wounds were created on the mice.Firstly, H2 S concentrations in the skins and granulation tissues were measured.The mRNA ex-pression of cystathionineγ-lyase ( CSE) was detected by RT-qPCR.The protein expression of CSE and MMP-9 were deter-mined by Western blot.The neutrophil and monocyte/macrophage infiltration was analyzed by immunohistochemistry me-thod.The levels of tumor necrosis factor (TNF)-αand interleukin (IL)-6 were measured by ELISA.Collagen formation was measured by Masson staining.RESULTS:The H2 S levels in the skin and granulation were significantly decreased in ob/ob mice and increased in the NaHS-treated mice ( P<0.05 ) .CSE expression at mRNA and protein levels was significantly decreased in ob/ob mice compared with the control mice (P<0.05).The wound healing period was significantly shorter in NaHS group than that in vehicle-treated ob/ob mice group (P<0.05), in which the insulin group had no difference with vehicle ob/ob mice group.The neutrophil and monocyte/macrophage infiltration, and TNF-αand IL-6 levels were signifi-cantly increased in ob/ob groups, but were decreased in NaHS group ( P<0.01 or P<0.05 ) .Meanwhile, NaHS in-creased collagen formation in the granulation tissues of ob/ob mice.CONCLUSION:H2 S/CSE down-regulation contributes
to impaired wound healing in diabetes, which is alleviated by exogenous H2 S possibly through anti-inflammation.