Effects of transforming growth factor beta1 (TGF beta 1) on p27kip1 levels in the gastric mucosa of suckling rats

Abstract

Transforming growth factor beta family (TGF betas) is composed of peptides that are present in milk and also expressed by the rat gastric epithelium, in which they control cell proliferation, differentiation, migration and apoptosis. Fasting can be used to challenge the gastric mucosa of 14-d-old rats by inducing hyperproliferation. However, when fasted pups are treated with TGF beta 1, we find inhibition of cell proliferation. Such effect is triggered by changes in the levels of cell cycle proteins, which include the increase of the CKI (cyclin-dependent kinase inhibitor) p27kip1. p27 is essential to retard and/or block cell cycle, specifically on G1/S transition. p27 concentration can be regulated at post-transcriptional, post-translational and degradation levels. In the current study our aim is to evaluate whether TGFbeta1-induced p27 increase in the gastric epithelium is related to the synthesis or degradation of this CKI. (AU)