Search

Prunella vulgaris has been widely used in the folk medicine of Northeastern Asian countries for the treatment of acute liver injury and infectious hepatitis. In the present study, the protective effect of aqueous extract from P. vulgaris was investigated on carbon tetrachloride-induced hepatic fibrosis in vivo. Our data showed that the administration of aqueous extract from P. vulgaris at doses of 50, 100, and 200 mg/kg significantly reduced the elevated serum levels of alanine aminotransferase, aspartate aminotransferase, type III precollagen, and hyaluronic acid in rats with hepatic fibrosis. In addition, aqueous extract from P. vulgaris also reduced the incidence of liver lesions and the formation of fibrous septa, and remarkably decreased the serum levels of inflammatory cytokines, platelet derived growth factor, interleukin-4, interleukin-8, and tumor necrosis factor alpha. Furthermore, aqueous extract from P. vulgaris significantly inhibited the activation of hepatic stellate cells by regulating the expression of α smooth muscle actin, transforming growth factor β1, and smad2 and also decreased the deposition of extracellular matrix proteins via regulating the expressions of tissue inhibitor of metalloproteinase-1, matrix metalloproteinase-2,-13. Real-time polymerase chain reaction further revealed that post-treatment with aqueous extract from P. vulgaris decreased the elevated levels of miR-34a and miR-199a-5p in hepatic fibrosis rats. These results demonstrated that aqueous extract from P. vulgaris alleviates carbon tetrachloride-induced hepatic fibrosis by inhibiting the activation of hepatic stellate cells, promoting collagenolysis and regulating fibrosis-related microRNAs. [ABSTRACT FROM AUTHOR]

A study led by researchers at the University of Barcelona has identified a potential new strategy to slow the development of liver fibrosis, a serious complication of metabolic fatty liver disease. The study found that activation of the PPARb/d-AMPK pathway can effectively slow the progression of liver fibrosis. Liver fibrosis is the most relevant risk factor for predicting liver disease-related mortality and overall mortality. The findings suggest that activating the PPARb/d-AMPK pathway could be an effective strategy to reduce the development of liver fibrosis. [Extracted from the article]

Hepatic stellate cells (HSCs) play a key role in the pathogenesis of liver fibrosis. In chronic liver injury, HSCs undergo transdifferentiation to an activated myofibroblastic phenotype and migrate to injured areas in response to chemotactic factors, producing extracellular matrix proteins such as collagen type I to repair the damage as well as overexpression of α-smooth muscle actin (α- SMA). Paeoniae Radix, the root of Paeonia lactiflora Pall, was investigated for PDGF-BB-induced HSC chemotaxis. Rat HSCs and LX-2, a human HSC cell line, were used for the in vitro experiments. Cell migration was analyzed by woundhealing and transwell assays. An ELISA and a Sircol collagen assay kit were used to detect the expressions of α-SMA and of collagen, respectively. Phosphorylations of mitogen-activated protein kinases, including ERK 1/2, p38, and JNK, were evaluated with immunoblotting. Results indicated that PDGF-BB increased migration as well as α-SMA and collagen expression in HSCs. Paeoniae Radix extracts and its active components, paeonol and 1,2,3,4,6-penta-O-galloyl-β-D-glucose (PGG), inhibited PDGF-BB-induced HSC migration and α-SMA and collagen expressions in a concentration-dependent manner. The inhibitory effects were associated with downregulation of PDGF receptor-α, ERK, p38, and JNK activation. Both paeonol and PGG participate in HSC migration, but via differential mechanisms. [ABSTRACT FROM AUTHOR]

Platelet-derived growth factor (PDGF) induces cell proliferation together with oxidative stress. The present study investigated the effects of salvianolic acid A (Sal A) and B (Sal B) on the PDGF-induced signaling cascades in hepatic stellate cells (HSCs). HSC-T6, a rat hepatic stellate cell line, was stimulated with PDGF (10 ng/mL). The inhibitory effects of Sal A and B on oxidative stress-related signaling pathways were assessed in vitro. The protein levels were measured by Western blotting. FACS analysis was applied to detect the thioredoxin (Trx) level. Sal A and B showed different inhibitory abilities on the PDGF-related pathway. Sal A inhibited 70-kDa ribosomal S6 kinase (p70s6k) and associated proteins. Sal B attenuated PDGF-induced c-jun-N-terminal kinase (JNK), p38, and PKC-δphosphorylations. Both Sal A and B diminished the activation of PKD, Trx, hemeoxygenase (HO)-1, and Nrf2. Taken together, our results showed that Sal A and B attenuated PDGF-induced ROS formation in HSCs, possibly through different signaling pathways. [ABSTRACT FROM AUTHOR]

Activation and proliferation of hepatic stellate cells (HSC) play an important role in the progress of liver fibrosis. HSC activation occurs in response to inflammatory cytokines, cellular interactions with immune cells, and morphogenetic signals. The literature hints to a role of the adaptor protein MyD88 in fibrosis. Although curcumin has been shown to exert inhibitory effects on the proliferation of HSC in vitro, its influence on the MyD88 pathway in HSC has remained unclear. Here, we investigated whether curcumin accelerates apoptosis of HSC through the MyD88 pathway. HSC (rat HSC T6) were divided into a control group, MyD88 small interfering RNA (siRNA) group, curcumin group, and curcumin + MyD88 siRNA group. The MyD88 siRNA groups were exposed to siRNA for 48 h. The curcumin groups were cultured in the presence of curcumin for 24 h. Apoptosis was detected by flow cytometry. For Toll-like receptor (TLR) 2 and 4 as well as MyD88 and the dependent factors NF-κB, TNF-α, and IL-1β, mRNA expression was detected by reverse transcription polymerase chain reaction (RT-PCR). For MyD88, protein expression was further observed by Western Blot. Both curcumin and MyD88 siRNA inhibited the mRNA expression of MyD88 pathway-related effectors (TLR2, TLR4, NF-κB, TNF-α, IL-1β) in HSC. Furthermore, both treatments reduced the expression of MyD88 protein in HSC and promoted their apoptosis. These effects were more obvious in the curcumin + MyD88 siRNA group. This study demonstrates that curcumin promotes apoptosis of activated HSC by inhibiting the expression of cytokines related to the MyD88 pathway. It elucidates the possible mechanisms of curcumin in inducing apoptosis of HSC through the MyD88 pathway. [ABSTRACT FROM AUTHOR]