Orientation algorithm for PPI networks based on network propagation approach.

Biological signal transduction of protein-protein interaction (PPI) networks occupies an important position in life activities because it affects the regulation mechanisms of growth, development and metabolism. To further understand the realization of cellular biological functions, we need to predict the directionality of PPIs. This study combines protein semantic similarity and overlapping clustering algorithm to improve the network propagation method for orientating signal transduction networks. This orientation algorithm was applied to an integrin-mediated PPI network (containing 1166 PPIs). As a result, 484 unoriented PPIs (forming protein complexes) and 682 oriented PPIs (interactions involving signal transmission) were obtained. Finally, in order to evaluate the effectiveness of this method, it was compared with the original method based on network propagation, and acceptable results were obtained.

Protective effects of pentadecapeptide derived from Cyclaina sinensis against cyclophosphamide-induced hepatotoxicity.

Our study was aimed at investigating the hepatoprotective effects of pentadecapeptide (RVAPEEHPVEGRYLV) from Cyclaina sinensis (SCSP) against cyclophosphamide (CTX)-induced hepatotoxicity in mice. Our results show that SCSP can significantly alleviate CTX-induced hepatotoxicity by decreasing the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglyceride (TG) and malondialdehyde (MDA), and increasing the levels of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT) in the liver. In addition, the levels of interleukin (IL)-1ß, IL-6, and tumor necrosis factor-α (TNF-α) were also significantly decreased in the liver tissues when treated with SCSP. Moreover, the protein levels of the toll-like receptor 4 (TLR4)-mediated nuclear factor-kappa B (NF-κB) pathway and apoptosis-related proteins were also restored by SCSP treatment. Overall, our results suggest that SCSP can potentially improve the CTX-induced hepatotoxicity.