20.500.12556/RUL-181447 Mitochondrial connexin 43 modulates metabolic stress adaptation in glioma cell lines Background Connexin 43 (CX43) is a hemichannel (HC)- and gap junction (GJ)-forming protein that mediates the exchange of small molecules between the intracellular and extracellular environments, as well as intercellular communication. In addition to this canonical role, recent studies have shown that its functions range from transcriptional regulation to intracellular homeostasis. The ability of CX43 to translocate into mitochondria suggests its involvement in energy metabolism. However, the functions of mitochondrial CX43 (mt-CX43) in neural cells remain unexplored. Methods Our study investigated the expression and localisation of mt-CX43 through western blot and immunofluorescence analyses in four immortalised human glioma cell lines: T98-G, A-172, CCF-STTG1, and U-87 MG. Additionally, targeted metabolomic analysis was conducted to assess changes in key metabolic pathways. Results Basal CX43 expression and extracellular stress factors, particularly cell density and extracellular pH fluctuations, significantly modulated the mitochondrial localisation of CX43. Inhibition of the heat shock protein 90 (HSP90) chaperone system by geldanamycin (GA) resulted in a marked reduction in mt-CX43, suggesting an import mechanism involving HSP90 and the translocase of the outer membrane (TOM) complex. In addition, the assessment of key metabolites revealed increased purine biosynthesis in T98-G cells exposed to GA treatment, characterised by lower basal CX43 expression and reduced mt-CX43 levels under stress conditions. Conversely, U-87 MG cells exhibited a stable NAD$^+$/NADH ratio and a significant increase in NADH levels, indicating a metabolic shift towards a more resilient state. Conclusions Our results suggest that mt-CX43 serves as a multifunctional regulator of metabolic adaptation and stress response in glioma cell lines. Our results extend the role of mt-CX43 as an essential factor in cellular metabolic plasticity, providing new insights into the modulation of metabolic imbalances and mitochondrial dysfunction. CX43 pH geldanamycin glioblastoma metabolism purine geldanamicin glioblastom metabolizem purin true false true Angleški jezik Slovenski jezik Članek v reviji 2026-04-08 09:44:00 2026-04-08 09:44:09 2026-05-20 08:50:23 0000-00-00 00:00:00 2025 0 0 19 str. iss. 1, art. 512 Vol. 23 2025 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 577:61 1478-811X 10.1186/s12964-025-02523-2 260784899 RAZ_Gervasi_Anna_2025.pdf RAZ_Gervasi_Anna_2025.pdf 1 BE5E62806510B59741E2C67192B697E5 bfba5cc40b42fc22d29b63422ea22682d67ff08768416f189269dc49b9935f5d c6af9dcf-331f-11f1-b0ab-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=231917 https://link.springer.com/article/10.1186/s12964-025-02523-2 1 8beb9c1d-331e-11f1-b0ab-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=231911 Medicinska fakulteta 0 0 0