Background and Purpose Vincamine has extensive biological and pharmaceutical activity. We examined the hepatoprotective effects and mechanisms by which vincamine suppresses hepatic fibrosis. Experimental Approach Hepatic stellate cells (HSCs), TGF- β stimulated, were cultured with either vincamine, farnesoid X receptor (NR1H4; FXR) agonist or antagonist. Further, C57BL/6 mice were given thioacetamide (TAA) to induce hepatic fibrosis and subsequently treated with vincamine or curcumin. Key Results Vincamine regulated the deposition of extracellular matrix (ECM), inflammatory factors and S100A4, and up-regulated FXR and TGR5 (GPBA receptor) in activated HSCs, by activating FXR. FXR deficiency blocked vincamine effect on FXR, TGR5, α -smooth muscle actin ( α -SMA) and IL1R1 in activated LX-2 cells. Vincamine corrected ECM imbalance, inflammatory secretion and FXR/TGR5 down-regulation in activated LX-2 cells with stimulating medium from LPS-primed THP-1 cells. S100A4 deficiency increased FXR and TGR5, and decreased IL-1β expression in activated THP-1. Further, S100A4 deficiency in activated macrophages could elevate FXR and TGR5 expression in activated LX-2, strengthening the impact of vincamine on α -SMA and IL-1β expression. Further, vincamine reduced serum ALT/AST levels, liver and intestinal histopathological changes, and caused ECM accumulation and protected the intestinal barrier in thioacetamide-induced hepatic fibrosis mice. Vincamine decreased inflammatory factors e.g. caspase 1 and IL-1β, and inhibited the S100A4-mediated FXR-TGR5 pathway. Conclusion and Implications Vincamine significantly reverses hepatic fibrosis via inhibiting S100A4 involved in the crosstalk between macrophages and HSCs, and by activating the FXR-TGR5 pathway. Targeting the S100A4-mediated FXR dependence on modulating the liver environment may be the key target of vincamine in inhibiting hepatic fibrosis. Graphical
Diabetic peripheral neuropathy (DPN) is a common complication of diabetes, which has yet no curable medication. Neuroinflammation and mitochondrial dysfunction are tightly linked to DPN pathology. G-protein-coupled receptor 40 (GPR40) is predominantly expressed in pancreatic β-cells, but also in spinal dorsal horn and dorsal root ganglion (DRG) neurons, regulating neuropathic pain. We previously have reported that vincamine (Vin), a monoterpenoid indole alkaloid extracted from Madagascar periwinkle , is a GPR40 agonist. In this study, we evaluated the therapeutic potential of Vin in ameliorating the DPN-like pathology in diabetic mice. Both STZ-induced type 1 (T1DM) and db/db type 2 diabetic (T2DM) mice were used to establish late-stage DPN model (DPN mice), which were administered Vin (30 mg·kg -1 ·d -1 , i.p.) for 4 weeks. We showed that Vin administration did not lower blood glucose levels, but significantly ameliorated neurological dysfunctions in DPN mice. Vin administration improved the blood flow velocities and blood perfusion areas of foot pads and sciatic nerve tissues in DPN mice. We demonstrated that Vin administration protected against sciatic nerve myelin sheath injury and ameliorated foot skin intraepidermal nerve fiber (IENF) density impairment in DPN mice. Moreover, Vin suppressed NLRP3 inflammasome activation through either β-Arrestin2 or β-Arrestin2/IκBα/NF-κB signaling, improved mitochondrial dysfunction through CaMKKβ/AMPK/SIRT1/PGC-1α signaling and alleviated oxidative stress through Nrf2 signaling in the sciatic nerve tissues of DPN mice and LPS/ATP-treated RSC96 cells. All the above-mentioned beneficial effects of Vin were abolished by GPR40-specific knockdown in dorsal root ganglia and sciatic nerve tissues. Together, these results support that pharmacological activation of GPR40 as a promising therapeutic strategy for DPN and highlight the potential of Vin in the treatment of this disease.