ACTA ENDOCRINOLOGICA (BUC)

Objective. This study was to investigate RIP140 expression levels in the pancreas and islet β-cells in mice and rats and the role of RIP140 in cultured β-cells using the mouse pancreatic β-cell line MIN6. Methods. The MIN6 cell line stably overexpressing RIP140 was used. The effects of RIP140 on cell viability, cell cycle, apoptosis, insulin secretion, and its regulated genes were analyzed using flow cytometry, the MTT assay, Western blot analysis, reverse transcriptase (RT)-PCR, and enzyme-linked immunosorbent assay (ELISA). Results. Most of insulin-positive cells in islets expressed RIP140. In MIN6 cells, overexpression of RIP140 inhibited cell viability by reducing the number of cells in S phase and inhibiting proliferating cell nuclear antigen (PCNA) expression. We also found that overexpression of RIP140 inhibited Bcl-2 and mRNA expression of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) and uncoupling protein 2 (UCP2) and increased levels of phosphorylated extracellular signalregulated protein kinases 1/2 (p-ERK1/2). However, apoptosis rate and levels of basal level of insulin secretion (BIS) and glucose-stimulated insulin (GSIS) were not significantly altered in MIN6 cells. Conclusions. RIP140 was expressed in the pancreas of mice and rats, particularly in β-cells, and participated in regulating β-cell function and proliferation.

Background. In vitro studies of the changes about osteoblastogenesis and adipogenesis potential of BMSCs were not clear. As it is the critical pathway for osteogenic differentiation and bone formation, whether or not Wnt/β- catenin signalling is involved in the changes of osteogenic and adipogenic potential of BMSCs and participates in bone content decrease of ovariectomized (OVX)osteoporosis rats has been rarely reported. Material/Methods. BMSCs from femurs of ovariectomzed rats were isolated and cultured in vitro. The proliferation potential of BMSCs was analysed by CCK-8 assays . Osteoblastic and adipogenic differentiation potential of the BMSCs was assessed by ALP activity assay, Alizarin red S staining, Oil red O staining and RT-PCR analysis. Results. The results demonstrated that BMSCs from bilateral ovariectomization rats were endowed with lower proliferation and osteoblastic differentiation potential but higher adipogenic potential than the control group in vitro. In addition, β-catenin was found to have been decreased in OVX BMSCs, indicating that Wnt/β-catenin signalling pathways were suppressed in OVX BMSCs . Conclusions. Results suggested that changes in the Wnt canonical signalling pathway may be related to imbalances of osteogenic and adipogenic potential of BMSCs, and this may be an important factor related to bone content decrease in ovariectomized osteoporosis rats.