Histone Deacetylases Enhance Ca2+-Activated K+ Channel KCa3.1 Expression in Murine Inflammatory CD4+ T Cells

• Published in: International journal of molecular sciences Vol. 19; no. 10; p. 2942
• Main Authors: Matsui, Miki, Terasawa, Kyoko, Kajikuri, Junko, Kito, Hiroaki, Endo, Kyoko, Jaikhan, Pattaporn, Suzuki, Takayoshi, Ohya, Susumu
• Format: Journal Article
• Language: English
• Published: MDPI 27.09.2018; MDPI AG
• Subjects: Ca2+-activated K+ channel; histone deacetylase; inflammatory bowel disease; inflammatory CD4+ T cell; KCa3.1
• ISSN: 1422-0067; 1422-0067
• DOI: 10.3390/ijms19102942

The up-regulated expression of the Ca2+-activated K+ channel KCa3.1 in inflammatory CD4+ T cells has been implicated in the pathogenesis of inflammatory bowel disease (IBD) through the enhanced production of inflammatory cytokines, such as interferon-γ (IFN-γ). However, the underlying mechanisms have not yet been elucidated. The objective of the present study is to clarify the involvement of histone deacetylases (HDACs) in the up-regulation of KCa3.1 in the CD4+ T cells of IBD model mice. The expression levels of KCa3.1 and its regulators, such as function-modifying molecules and transcription factors, were quantitated using a real-time polymerase chain reaction (PCR) assay, Western blotting, and depolarization responses, which were induced by the selective KCa3.1 blocker TRAM-34 (1 μM) and were measured using a voltage-sensitive fluorescent dye imaging system. The treatment with 1 μM vorinostat, a pan-HDAC inhibitor, for 24 h repressed the transcriptional expression of KCa3.1 in the splenic CD4+ T cells of IBD model mice. Accordingly, TRAM-34-induced depolarization responses were significantly reduced. HDAC2 and HDAC3 were significantly up-regulated in the CD4+ T cells of IBD model mice. The down-regulated expression of KCa3.1 was observed following treatments with the selective inhibitors of HDAC2 and HDAC3. The KCa3.1 K+ channel regulates inflammatory cytokine production in CD4+ T cells, mediating epigenetic modifications by HDAC2 and HDAC3.