Transcriptional regulation of H-Ferritin gene after TSH stimulation: NF-Y7p300 complex

TSH modulates survival, proliferation and differentiation in thyreocyte by binding membrane receptors specific (TSH-R) via the cAMP/PKA pathway. cAMP activates any transcription factors, such as CREB and NF-Y. NF-Y on the H ferritin promoter binds an inverted CAAT box recognized by a protein complex called the B-box binding factor (Bbf). Bbf is composed of the trimeric transcription factor NF-Y, that directly binds DNA, of the co-activator p300 and of the histone acetylase pCAF. Moreover, cAMP and its analogs have been shown to promote the binding, thus inducing ferritin gene transcription. The ferritin expression is regulated by many pathological conditions, like inflammation and oxidative stress, is stimolated during development, cell differentiation and is modulated by several factor, such as cell growth, hormones, and cytokines. In particular, the H- ferritin synthesis in thyroid cells is stimulated by hormones such as TSH. Aim of the present study is to analyze the expression of the H-ferritin gene after TSH stimulation, with particular attention to transcriptional modulation and the role played by the complex NFY/ p300. To this end, thyroid cells were subjected to TSH by using increasing amounts. H ferritin mRNA levels of treated and untreated cells with TSH were valutated by Northen Blot and RT PCR assays. Moreover, protein levels were estimated by western blot assays. The analysis of transcription induction efficiency were carried on by transient transfection experiments in cell treated and untreated with TSH. Our results showed that H-Ferritin transcription is increased after TSH induction.