NF-ƒkB activation in non-genomic effects of thyroid hormones on murine T lymphoma cells.

BARREIRO ARCOS ML; FARÍAS RN; KLECHA AJ; STERLE H; GENARO AM; CREMASCHI GA

Madrid, España

Congreso; 2nd Iberoamerican Congress on Neuroimmunomodulation; 2007

International Society for Neuroimmunomodulation

Thyroid hormones (TH) exert a broad range of effects on development, growth and differentiation. Direct actions of TH on lymphocyte are now emerging. We have previously demonstrated that TH induce division of quiescent BW 5147 (BW) T lymphoma cells through protein kinase C (PKC) zeta and inducible nitric oxide synthase (iNOS) activities. To further characterized the intracellular mechanisms non-genomic actions of TH, were analyzed on BW cells using T3 and T4 hormones coupled to agarose (T3-ag and T4-ag). Both T3-ag and T4-ag were able to induce BW cell division although their effects on proliferation were lower than those elicited by TH. Agarose coupled hormones induced the rapid translocation of PKC to cell membrane, IkB degradation and NF-kB translocation to the nucleus. BW cell pretreatment with PKC zeta pseudosubstrate inhibited TH effects on proliferation as well how NF-kB activation. HT, but not agarose coupled hormones, were able to induce iNOS protein and mRNA expression. As T3-ag and T4-ag do not cross cell membrane, the cellular growth mediated by HT involved besides HT genomic actions and non genomic activation of PKC and NF-KB.