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Hepatic stellate cells (HSCs) play a critical role in the pathogenesis and reversal of liver fibrosis. Targeting HSCs is of great significance in the treatment of hepatic fibrosis, and has attracted wide attention of scholars. Here we demonstrated that expression of geranylgeranyldiphosphate synthase (GGPPS) predominantly increased in HSCs in murine fibrotic liver. HSC-specific knockdown of GGPPS using vitamin A-coupled liposome carrying siRNA-ggpps decreased activation of HSCs and alleviated fiber accumulation in vivo. Furthermore, our in vitro studies showed that GGPPS was up-regulated during HSCs activation in TGF-β1-dependent manner. Inhibition of GGPPS suppressed TGF-β1 induced F-actin reorganization and HSCs activation in LX-2 cells. Further, we found that GGPPS regulated HSCs activation and liver fibrosis possibly by enhancing RhoA/Rock kinase signaling. So its concluded that GGPPS promotes liver fibrosis by activating HSCs, which may represent a potential target for anti-fibrosis therapies.

Background & Aims Liver injury triggers a highly organized and ordered liver regeneration (LR) process. Once regeneration is complete, a stop signal ensures that the regenerated liver is an appropriate functional size. The inhibitors and stop signals that regulate LR are unknown, and only limited information is available about these mechanisms. Methods A 70% partial hepatectomy (PH) was performed in hepatocyte-specific PP2Acα-deleted ( PP2Acα −/− ) and control (PP2Acα +/+ ) mice. LR was estimated by liver weight, serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels and cell proliferation, and the related cellular signals were analyzed. Results We found that the catalytic subunit of PP2A was markedly upregulated during the late stage of LR. PP2Acα −/− mice showed prolonged LR termination, an increased liver size compared to the original mass and lower levels of serum ALT and AST compared with control mice. In these mice, cyclin D1 protein levels, but not mRNA levels, were increased. Mechanistically, AKT activated by the loss of PP2Acα inhibited glycogen synthase kinase 3β (GSK3β) activity, which led to the accumulation of cyclin D1 protein and accelerated hepatocyte proliferation at the termination stage. Treatment with the PI3K inhibitor wortmannin at the termination stage was sufficient to inhibit cyclin D1 accumulation and hepatocyte proliferation. Conclusions PP2Acα plays an essential role in the proper termination of LR via the AKT/GSK3β/Cyclin D1 pathway. Our findings enrich the understanding of the molecular mechanism that controls the termination of LR and provides a potential therapeutic target for treating liver injury.

To investigate the expression of insulin-like growth factor-I receptor (IGF-IR) and sushi domaincontaining protein 3 (SUSD3) in breast cancer tissue, and analyze their relationship with clinical parameters and the correlation betweenthe two proteins.The expression of IGF-IR and SUSD3 in 100 cases of breast cancer tissues and adjacent normal breast tissues after surgery was detected by immunohistochemical technique MaxVisionTM, and the relationship with clinical pathological features was further analyzed.The positive rate of IGF-IR protein was 86.0% in breast cancer, higher than 3.0% in adjacent normalbreast tissue (P0.05) .The positive expression rate of SUSD3 protein was 78.0% in breast cancer, higher than 2.0% in adjacent normal breast tissue (P0.05). The expression of IGF-IR and SUSD3 was related to estrogen receptor and pathological types (P0.05),but not with age, stage, the expression of HER-2 and Ki-67 (P0. 05). The expression of IGF-IR and SUSD3 in breast cancer tissue was positively related (r= 0.553, P0.01).The expression of IGF-IR and SUSD3 may be correlated to the occurrence and development of breast cancer. The combined detection of IGF-IR, SUSD3 and ER may play an important role in judging prognosis and guiding adjuvant therapy after surgery of breast cancer.