ABSTRACT
Oligopeptide transporter 1 (Pept1) is located on the brush border membrane of the intestinal epithelium and plays an important role in dipeptide and tripeptide absorption from protein digestion. In this study, we cloned and characterized the cDNA sequence of Janus kinase 2 (JAK2) from Ctenopharyngodon idella. The expression patterns of JAK2 in various tissues and developmental stages were characterized by quantitative real-time PCR (qRT-PCR). The mRNA expression levels of JAK2 and Pept1 regulated by leptin in the intestine were also analyzed in vitro and in vivo. The cDNA sequence of JAK2 is 3378 bp in length, and the mRNA of JAK2 was broadly expressed in all tissues and embryonic stages of C. idella analyzed. In addition, we found that leptin regulated expression of JAK2 and Pept1 in the intestine; Pept1 expression was down-regulated by the JAK2 inhibitor AG490 in vivo and in vitro. Furthermore, luciferase experiments showed that overexpression of the JAK2 gene significantly upregulated the activity of the Pept1 5' regulatory sequence in C. idella. In conclusion, these results may help in elucidating the regulatory effect of the leptin-mediated JAK2 pathway on intestinal Pept1 expression in C. idella and the molecular mechanism of peptide transport by the intestinal transporter Pept1 in fishes.
ABSTRACT
The inhibitive effects on angiogenesis and the potential mechanism by terpenoids from Bletilla striata were investigated in the study. Terpenoids were separated and purified from Bletilla striata by extraction and chromatography. The terpenoid and its crude extracts were used to treat on blood vessel of chick chorioallantoic membrane (CAM), as well as human umbilical vein endothelial cell (HUVEC). Our results demonstrated that the crude extracts containing the terpenoids could inhibit CAM angiogenesis and pure terpenoid sample could prohibit HUVEC proliferation and induce HUVEC undergoing apoptosis, which showed an apparent apoptotic characterizations, such as cell shrinking, blebbing of cell membrane, nucleus cracking, chromatin condensation and margination, apoptotic body formation and DNA degradation. Therefore, the inhibition on angiogenesis by terpenoids from Bletilla striata is depended on the induction of apoptosis to endothelial cells.
