title: SIRT1 contributes to aldose reductase expression through modulating NFAT5 under osmotic stress: In vitro and in silico insights.
abstract: So far, a myriad of molecules were characterized to modulate NFAT5 and its downstream targets. Among these NFAT5 modifiers, SIRT1 was proposed to have a promising role in NFAT5 dependent events, yet the exact underlying mechanism still remains obscure. Hence, the link between SIRT1 and NFAT5-aldose reductase (AR) axis under osmotic stress, was aimed to be delineated in this study. A unique osmotic stress model was generated and its mechanistic components were deciphered in U937 monocytes. In this model, AR expression and nuclear NFAT5 stabilization were revealed to be positively regulated by SIRT1 through utilization of pharmacological modulators. Overexpression and co-transfection studies of NFAT5 and SIRT1 further validated the contribution of SIRT1 to AR and NFAT5. The involvement of SIRT1 activity in these events was mediated via modification of DNA binding of NFAT5 to AR ORE region. Besides, NFAT5 and SIRT1 were also shown to co-immunoprecipitate under isosmotic conditions and this interaction was disrupted by osmotic stress. Further in silico experiments were conducted to investigate if SIRT1 directly targets NFAT5. In this regard, certain lysine residues of NFAT5, when kept deacetylated, were found to contribute to its DNA binding and SIRT1 was shown to directly bind K282 of NFAT5. Based on these in vitro and in silico findings, SIRT1 was identified, for the first time, as a novel positive regulator of NFAT5 dependent AR expression under osmotic stress in U937 monocytes.
authors: Molecular Biology, Genetics and Bioengineering Program, Faculty of Engineering and Natural Sciences, Sabanci University, 34956, Orhanli, Tuzla, Istanbul, Turkey. Electronic address: cantimucin@sabanciuniv.edu.
authors: Ahmet Can
authors: AC
authors: Timucin
authors: Molecular Biology, Genetics and Bioengineering Program, Faculty of Engineering and Natural Sciences, Sabanci University, 34956, Orhanli, Tuzla, Istanbul, Turkey. Electronic address: cagribodur@gmail.com.
authors: Cagri
authors: C
authors: Bodur
authors: Molecular Biology, Genetics and Bioengineering Program, Faculty of Engineering and Natural Sciences, Sabanci University, 34956, Orhanli, Tuzla, Istanbul, Turkey. Electronic address: huveyda@sabanciuniv.edu.
authors: Huveyda
authors: H
authors: Basaga
mesh_terms: D000449:Aldehyde Reductase / Q000096:biosynthesis*; D001665:Binding Sites / Q000235:genetics; D045744:Cell Line, Tumor; D004268:DNA-Binding Proteins / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D062105:Molecular Docking Simulation; D056004:Molecular Dynamics Simulation; D009997:Osmotic Pressure / Q000502:physiology*; D056564:Sirtuin 1 / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; C118125:NFAT5 protein, human; D014157:Transcription Factors; D000449:Aldehyde Reductase; C447939:SIRT1 protein, human; D056564:Sirtuin 1
keywords: Aldose reductase; Deacetylation; NFAT5; Osmotic stress; SIRT1