ELABELA-derived peptide ELA13 attenuates kidney fibrosis by inhibiting the Smad and ERK signaling pathways

Kidney fibrosis is an inevitable result of various chronic kidney diseases(CKDs)and significantly contributes to end-stage renal failure.Currently,there is no specific treatment available for renal fibrosis.ELA13(amino acid sequence:RRCMPLHSRVPFP)is a conserved region of ELABELA in all vertebrates;however,its biological activity has been very little studied.In the present study,we evaluated the therapeutic effect of ELA13 on transforming growth factor-β1(TGF-β1)-treated NRK-52E cells and unilateral ureteral occlusion(UUO)mice.Our results demonstrated that ELA13 could improve renal function by reducing creatinine and urea nitrogen content in serum,and reduce the expression of fibrosis biomarkers confirmed by Masson staining,immunohistochemistry,real-time polymerase chain reaction(RT-PCR),and western blot.Inflammation biomarkers were increased after UUO and decreased by administration of ELA13.Furthermore,we found that the levels of essential molecules in the mothers against decapentaplegic(Smad)and extracellular signal-regulated kinase(ERK)pathways were reduced by ELA13 treatment in vivo and in vitro.In conclusion,ELA13 protected against kidney fibrosis through inhibiting the Smad and ERK signaling pathways and could thus be a promising candidate for anti-renal fibrosis treatment.

Design of a highly potent GLP-1R and GCGR dual-agonist for recovering hepatic fibrosis

Currently, there is still no effective curative treatment for the development of late-stage liver fibrosis. Here, we have illustrated that TB001, a dual glucagon-like peptide-1 receptor/glucagon receptor(GLP-1 R/GCGR) agonist with higher affinity towards GCGR, could retard the progression of liver fibrosis in various rodent models, with remarkable potency, selectivity, extended half-life and low toxicity. Four types of liver fibrosis animal models which were induced by CCl_(4), a-naphthyl-isothiocyanate(ANIT), bile duct ligation(BDL) and Schistosoma japonicum were used in our study. We found that TB001 treatment dose-dependently significantly attenuated liver injury and collagen accumulation in these animal models. In addition to decreased levels of extracellular matrix(ECM) accumulation during hepatic injury, activation of hepatic stellate cells was also inhibited via suppression of TGF-β expression as well as downstream Smad signaling pathways particularly in CCl_(4)-and S. japonicum-induced liver fibrosis. Moreover, TB001 attenuated liver fibrosis through blocking downstream activation of proinflammatory nuclear factor kappa B/NF-kappa-B inhibitor alpha(NFκB/IKBa) pathways as well as cJun N-terminal kinase(JNK)-dependent induction of hepatocyte apoptosis. Furthermore, GLP-1 R and/or GCGR knock-down results represented GCGR played an important role in ameliorating CCl_(4)-induced hepatic fibrosis. Therefore, TB001 can be used as a promising therapeutic candidate for the treatment of multiple causes of hepatic fibrosis demonstrated by our extensive pre-clinical evaluation of TB001.