Corticosteroids induce the differential expression of TGFbeta isoforms, receptors and signaling in the gastric mucosa of suckling rats.
Glucocorticoids inhibit the cell proliferation in the gastric epithelium, and induce differentiation, migration and death. The mechanism by which these effects are triggered and controlled is still discussed and can involve the transcription and activation of transforming growth factor beta (TGFbeta). The present study was conducted to evaluate the effect of hydrocortisone short-term treatment on tissue level and distribution of TGFbeta isoforms, receptors and signaling through Smad2/3. To achieve that, 18-day-old rats were injected with hydrocortisone (50 mg/Kg b.wt.) for 0, 1 and 3 h. The stomachs were collected and processed for immunohistochemistry and western blotting. We observed that the treatment for 3 h increased the number of labeled epithelial cells for TGFbeta1 (p < 0.05), decreased the distribution of TGFbeta2 (p < 0.05) and did not alter TGFbeta3, TbetaRI and TbetaRII status. The levels of TGFbeta1 and receptors were checked by western blotting and results corroborate the immunodetection. We also found that phosphorylation of Smad2/3 into Smad2P increased after 3 h (p < 0.05), indicating that the high level TGFbeta1 was active on the cells. We suggest that glucocorticoids differentially regulate the expression of TGFbeta isoforms, receptors and signaling, and so TGFbeta1 might be involved in the inhibitory pathway triggered by the hormone.
Ogias
Daniela
D
Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of São Paulo, Brazil.
Bitencourt
Bianca
B
Alvares
Eliana Parisi
EP
Gama
Patrícia
P
D000818:Animals; D000833:Animals, Suckling / Q000033:anatomy & histology / Q000378:metabolism*; D005260:Female; D005753:Gastric Mucosa / Q000166:cytology / Q000502:physiology*; D006854:Hydrocortisone / Q000008:administration & dosage / Q000378:metabolism*; D011247:Pregnancy; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D018125:Receptors, Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D051899:Smad2 Protein / Q000235:genetics / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism*
D020033:Protein Isoforms; D018125:Receptors, Transforming Growth Factor beta; D051899:Smad2 Protein; C497784:Smad2 protein, rat; D016212:Transforming Growth Factor beta; D006854:Hydrocortisone