Visceral adipogenesis inhibited by Pref-1 is associated with peritoneal angiogenesis

Tetramethylpyrazine Ameliorates Peritoneal Angiogenesis by Regulating VEGF/Hippo/YAP Signaling

Angiogenesis of human peritoneal vascular endothelial cells (HPVECs), linked to vascular endothelial growth factor (VEGF)/VEGF receptor 2 (VEGFR2) signaling, is a complication of peritoneal fibrosis (PF). Hippo/YAP signaling interacts with VEGF/VEGFR2 signaling, but the effect on peritoneal angiogenesis and PF has not been studied. We tested VEGF/Hippo/YAP inhibition by tetramethylpyrazine (TMP) in PF mice and HPVECs. This treatment ameliorated peritoneal dialysis (PD)–induced angiogenesis and PF. In mice, PF was associated with upregulation of VEGF, and TMP ameliorated submesothelial fibrosis, perivascular bleeding, and Collagen I abundance. In HPVECs, angiogenesis occurred due to human peritoneal mesothelial cells (HPMCs)–conditioned medium, and TMP alleviated HPVECs migration, tube formation, and YAP nuclear translocation. YAP knockdown PF mouse and HPVEC models were established to further confirm our finding. YAP deletion attenuated the PD-induced or VEGF-induced increase in angiogenesis and PF. The amount of CYR61 and CTGF was significantly less in the YAP knockdown group. To study the possibility that TMP could benefit angiogenesis, we measured the HPVECs migration and tube formation and found that both were sharply increased in YAP overexpression; TMP treatment partly abolished these increases. As well, the amount of VEGFR localized in the trans-Golgi network was lower by double immunofluorescence; VEGFR and its downstream signaling pathways including p-ERK, p-P38, and p-Akt were more in HPVECs with YAP overexpression. Overall, TMP treatment ameliorated angiogenesis, PF, and peritoneum injury. These changes were accompanied by inhibition of VEGF/Hippo/YAP.

Molecular characterization of fibroblast growth factor-16 and its role in promoting the differentiation of intramuscular preadipocytes in goat

Fat metabolism is an important and complex biochemical reaction in vivo and is regulated by many factors. Recently, the findings on high expression of fibroblast growth factor-16 (FGF16) in brown adipose tissue have led to an interest in exploring its role in lipogenesis and lipid metabolism. The study cloned the goat's FGF16 gene 624 bp long, including the complete open reading frame that encodes 207 amino acids. We found that FGF16 expression is highest in goat kidneys and hearts, followed by subcutaneous fat and triceps. Moreover, the expression of FGF16 reached its peak on the 2nd day of adipocyte differentiation (P < 0.01) and then decreased significantly. We used overexpression and interference to study the function of FGF16 gene in goat intramuscular preadipocytes. Silencing of FGF16 decreased adipocytes lipid droplet aggregation and triglyceride synthesis. This is in contrast to the situation where FGF16 is overexpressed. Furthermore, knockdown of FGF16 also caused down-regulated expression of genes associated with adipocyte differentiation including CCAAT enhancer-binding protein beta (P < 0.01), fatty acid-binding protein-2 (P < 0.01) and sterol regulatory element binding protein-1 (P < 0.05), but the preadipocyte factor-1 was up-regulated. At the same time, the genes adipose triglyceride lipase (P < 0.01) and hormone-sensitive lipase (P < 0.05) associated with triglyceride breakdown were highly expressed. Next, we locked the fibroblast growth factor receptor-4 (FGFR4) through the protein interaction network and interfering with FGF16 to significantly reduce FGFR4 expression. It was found that the expression profile of FGFR4 in adipocyte differentiation was highly similar to that of FGF16. Overexpression and interference methods confirmed that FGFR4 and FGF16 have the same promoting function in adipocyte differentiation. Finally, using co-transfection technology, pc-FGF16 and siRNA-FGFR4, siRNA2-FGF16 and siRNA-FGFR4 were combined to treat adipocytes separately. It was found that in the case of overexpression of FGF16, cell lipid secretion and triglyceride synthesis showed a trend of first increase and then decrease with increasing interference concentration. In the case of interference with FGF16, lipid secretion and triglyceride synthesis showed a downward trend with the increase of interference concentration. These findings illustrated that FGF16 mediates adipocyte differentiation via receptor FGFR4 expression and contributed to further study of the functional role of FGF16 in goat fat formation.