| Summary: | 博士 === 國立陽明大學 === 藥理學研究所 === 105 === Notch1 signaling involves in several physiological and pathological cellular processes, including proliferation, apoptosis, stem cell maintenance and regulation of erythroid and megakaryocyte differentiation. Notch1 intracellular domain (N1IC), the activated form of Notch1, induced TRPA1 expression. TRPA1 is a non-selective calcium channel. Inflammatory cytokines enhance TRPA1 expression, and TRPA1 activation induces neurotransmitter release. Inflammatory cytokines suppress erythroid differentiation and result in anemia. The roles of TRPA1 in erythroid/megakaryocyte differentiation are poorly understood. Herein, the data indicated that N1IC activated TRPA1 promoter in a CBF1-independent manner. N1IC enhanced TRPA1 promoter activity via Ets-1, and both of them bound to TRPA1 promoter. N1IC modulated TRPA1 promoter depend on promoter methylation, and N1IC and Ets-1 inhibited DNA methyltransferase 3B (DNMT3B) expression synergistically. TRPA1 decreased hemin-induced erythroid differentiation of K562 and HEL cells. TRPA1 agonist AITC suppressed erythroid differentiation and increased phosphorylation of ERK in K562 and HEL cells, which were reversed by TRPA1 antagonist or EGTA pretreatment. TRPA1 mediated N1IC- or Ets-1- restrained erythroid differentiation. TRPA1 improved PMA-induced megakaryocyte differentiation, and the levels of megakaryocytic markers were increased. Notch1 receptor or Ets-1 knockdown reduced me megakaryocyte differentiation, which could be restored by TRPA1 expression. Knockdown of DNMT3B increased TRPA1 level, inhibited erythroid differentiation as well as promoted megakaryocyte differentiation. Moreover, TRPA1 inhibition enhanced migration, invasion and colony forming abilities of K562 cells. These results demonstrate that N1IC-induced TRPA1 play a critical role in the regulation of erythroid and megakaryocyte differentiation.
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