Modulation of tissue transglutaminase production on intestinal epithelial cells by proinflamatory stimulation

BAYARDO, M. RUMBO, M., AND CHIRDO

Cordoba Argenitna

Congreso; VIII Congreso de la Asociación Latinoamericana de Inmunología (ALAI); 2005

Tranglutaminase 2 (TG2)  participates in diverse biological processes such as wound healing, signalling, differentiation and apoptosis. TG2 presents two different catalytic sites. One has a Ca+2-dependent transamidation activity, while the second is a GTP/GDP exchanger. TG2 is upregulated in the intestinal mucosa in active coeliac patients being involved in the pathogenic mechanism. TH1 cytokines and innate response take part in the mucosal damage in coeliacs. It has been shown on different in vitro systems that long term (> 24hs) treatments with the proinflammatory cytokines TNF and IL-1, produce TG2 upregulation. This modulation can be due to either signalling pathways triggered by specific primary receptors or by the activity of products triggered upon primary stimulation. The aim of this study was to investigate whether short-term proinflammatory stimulus modulate TG2 expression.Experiments were performed on Caco-2 cells, human epithelial cell line used as a model for enterocytes. We have cloned the full length TG2 gene from total RNA from Caco-2 cells (Genbank AY675221). Primers amplifying a 414pb TG2 fragment were used for the RT-PCR analysis on mRNA samples from Caco-2 cells incubated with (100ng/ml TNF, 10ng/ml IL-1 and 1 µg/ml flagellin) for 2, 4, 8 and 24 h. No differences were found among the different conditions. Coincident results were obtained at the protein level, when the protein fraction obtained after Trizol extraction, was analyzed by western blot using monoclonal anti-TG2 antibodies. In conclusion, short term incubation with innate (flagellin) or proinflammatory (TNF, IL-1) stimulus did not produce upregulation of TG2 mRNA in