title: TNFα driven HIF-1α-hexokinase II axis regulates MHC-I cluster stability through actin cytoskeleton.
abstract: Hypoxia-inducible Factor-1α (HIF-1α)-regulated expression of Hexokinase-II (HKII) remains a cornerstone in the maintenance of high metabolic demands subserving various pro-tumor functions including immune evasion in gliomas. Since inflammation-induced HIF-1α regulates Major Histocompatibility Complex class I (MHC-I) gene expression, and as cytoskeletal dynamics affect MHC-I membrane clusters, we investigated the involvement of HIF-1α-HKII axis in Tumor Necrosis Factor-α (TNFα)-mediated MHC-I membrane cluster stability in glioma cells and the involvement of actin cytoskeleton in the process. TNFα increased the clustering and colocalization of MHC-I with cortical actin in a HIF-1α dependent manner. siRNA mediated knockdown of HIF-1α as well as enzymatic inhibition of HK II by Lonidamine, delocalized mitochondrially bound HKII. This altered subcellular HKII localization affected TNFα-induced cofilin activation and actin turnover, as pharmacological inhibition of HKII by Lonidamine decreased Actin-related protein 2 (ARP2)/cofilin interaction. Photobleaching studies revealed destabilization of TNFα- induced stable MHC-I membrane clusters in the presence of Lonidamine and ARP2 inhibitor CK666. This work highlights how TNFα triggers a previously unknown function of metabolic protein HKII to influence an immune related outcome. Our study establishes the importance of inflammation induced HIF-1α in integrating two crucial components- the metabolic and immune, through reorganization of cytoskeleton.
authors.affiliation: Molecular & Cellular Neuroscience Division, National Brain Research Centre, Manesar, Haryana 122051, India. Electronic address: sadashibghosh@gmail.com.
authors.forename: Sadashib
authors.initials: S
authors.lastname: Ghosh
authors.affiliation: Molecular & Cellular Neuroscience Division, National Brain Research Centre, Manesar, Haryana 122051, India.
authors.forename: Piyushi
authors.initials: P
authors.lastname: Gupta
authors.affiliation: Molecular & Cellular Neuroscience Division, National Brain Research Centre, Manesar, Haryana 122051, India.
authors.forename: Ellora
authors.initials: E
authors.lastname: Sen
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism*; D045744:Cell Line, Tumor; D006593:Hexokinase / Q000378:metabolism*; D015395:Histocompatibility Antigens Class I / Q000378:metabolism*; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism*; D055550:Protein Stability; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
chemical_list: D015395:Histocompatibility Antigens Class I; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D014409:Tumor Necrosis Factor-alpha; D006593:Hexokinase
keywords: Actin; Hexokinase; Inflammation; MHC; Metabolism; TNFα