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Hepatic stellate cells are of mesenchymal cell type located in the space of Disse. Upon liver injury, HSCs transactivate into myofibroblasts with increase in expression of fibrillar collagen, especially collagen I and III, leading to liver fibrosis. Previous studies have shown mTOR signaling is activated during liver fibrosis. However, there is no direct evidence in vivo. The aim of this study is to examine the effects of conditional deletion of TSC1 in mesenchymal on pathogenesis of liver fibrosis. Crossing mice bearing the floxed TSC1 gene with mice harboring Col1α2-Cre-ER(T) successfully generated progeny with a conditional knockout of TSC1 (TSC1 CKO) in collagen I expressing mesenchymal cells. TSC1 CKO and WT mice were subjected to CCl4, oil or CCl4+ rapamycin treatment for 8 weeks. TSC1 CKO mice developed pronounced liver fibrosis relative to WT mice, as examined by ALT, hydroxyproline, histopathology, and profibrogenic gene. Absence of TSC1 in mesenchymal cells induced proliferation and prevented apoptosis in activated HSCs. However, there were no significant differences in oil-treated TSC1 CKO and WT mice. Rapamycin, restored these phenotypic changes by preventing myofibroblasts proliferation and enhancing their apoptosis. These findings revealed mTOR overactivation in mesenchymal cells aggravates CCl4− induced liver fibrosis and the rapamycin prevent its occurance. [ABSTRACT FROM AUTHOR]

Hepatic stellate cells are of mesenchymal cell type located in the space of Disse. Upon liver injury, HSCs transactivate into myofibroblasts with increase in expression of fibrillar collagen, especially collagen I and III, leading to liver fibrosis. Previous studies have shown mTOR signaling is activated during liver fibrosis. However, there is no direct evidence in vivo. The aim of this study is to examine the effects of conditional deletion of TSC1 in mesenchymal on pathogenesis of liver fibrosis. Crossing mice bearing the floxed TSC1 gene with mice harboring Col1α2-Cre-ER(T) successfully generated progeny with a conditional knockout of TSC1 (TSC1 CKO) in collagen I expressing mesenchymal cells. TSC1 CKO and WT mice were subjected to CCl 4 , oil or CCl 4 + rapamycin treatment for 8 weeks. TSC1 CKO mice developed pronounced liver fibrosis relative to WT mice, as examined by ALT, hydroxyproline, histopathology, and profibrogenic gene. Absence of TSC1 in mesenchymal cells induced proliferation and prevented apoptosis in activated HSCs. However, there were no significant differences in oil-treated TSC1 CKO and WT mice. Rapamycin, restored these phenotypic changes by preventing myofibroblasts proliferation and enhancing their apoptosis. These findings revealed mTOR overactivation in mesenchymal cells aggravates CCl 4 - induced liver fibrosis and the rapamycin prevent its occurance.

Objective: To explore the molecular mechanism in the formation of unstable plaques., Methods: The cDNA microarray E-MTAB-2055 was downloaded from ArrayExpress database to screen the differentially expressed genes in 24 ruptured plaques against 24 stable plaques. Functional enrichment analysis was conducted to define the biological processes and pathways involved in disease progression. The protein-protein interaction network was constructed to identify the risk modules with close interactions. Five pairs of carotid specimens were used to validate 3 differentially expressed genes of the risk modules by real-time PCR., Results: A total of 439 genes showed differential expression in our analysis, including 232 up-regulated and 207 down-regulated genes according to the data filter criteria. Immune-related biological processes and pathways were greatly enriched. The protein-protein interaction network and module analysis suggested that TYROBP, VCL and CXCR4 might play critical roles in the development of unstable plaques, and differential expressions of CXCR4 and TYROBP in carotid plaques were confirmed by real-time PCR., Conclusion: Our study shows the differential gene expression profile, potential biological processes and signaling pathways involved in the process of plaque rupture. TYROBP may be a new candidate disease gene in the pathogenesis of unstable plaques.