Mmakola, Khomotso Madimetsa ShelboyBalmith, MarissaSteel, Helen CarolynSaid, MohamedPotjo, MoliehiVan der Mescht, Mieke AdriHlatshwayo, NomsaMeyer, Pieter Willem AdriaanTintinger, Gregory RonaldAnderson, RonaldCholo, Moloko C.2025-03-142025-03-142024-12-04Mmakola, K.; Balmith, M.; Steel, H.; Said, M.; Potjo, M.; van der Mescht, M.; Hlatshwayo, N.; Meyer, P.; Tintinger, G.; Anderson, R.; et al. Sodium, Potassium-Adenosine Triphosphatase as a Potential Target of the Anti-Tuberculosis Agents, Clofazimine and Bedaquiline. International Journal of Molecular Sciences 2024, 25, 13022. https://DOI.org/10.3390/ijms252313022.1661-6596 (print)1422-0067 (online)10.3390/ijms252313022http://hdl.handle.net/2263/101501DATA AVAILABILITY STATEMENT : All the datasets generated for this study are included in the article and Supplementary Materials.Multidrug-resistant tuberculosis (MDR-TB) patients are treated with a standardised, short World Health Organization (WHO) regimen which includes clofazimine (CFZ) and bedaquiline (BDQ) antibiotics. These two antibiotics lead to the development of QT prolongation in patients, inhibiting potassium (K+) uptake by targeting the voltage-gated K+ (Kv)11.1 (hERG) channel of the cardiomyocytes (CMs). However, the involvement of these antibiotics to regulate other K+ transporters of the CMs, as potential mechanisms of QT prolongation, has not been explored. This study determined the effects of CFZ and BDQ on sodium, potassium–adenosine triphosphatase (Na+,K+-ATPase) activity of CMs using rat cardiomyocytes (RCMs). These cells were treated with varying concentrations of CFZ and BDQ individually and in combination (1.25–5 mg/L). Thereafter, Na+,K+-ATPase activity was determined, followed by intracellular adenosine triphosphate (ATP) quantification and cellular viability determination. Furthermore, molecular docking of antibiotics with Na+,K+-ATPase was determined. Both antibiotics demonstrated dose–response inhibition of Na+,K+-ATPase activity of the RCMs. The greatest inhibition was demonstrated by combinations of CFZ and BDQ, followed by BDQ alone and, lastly, CFZ. Neither antibiotic, either individually or in combination, demonstrated cytotoxicity. Molecular docking revealed an interaction of both antibiotics with Na+,K+-ATPase, with BDQ showing higher protein-binding affinity than CFZ. The inhibitory effects of CFZ and BDQ, individually and in combination, on the activity of Na+,K+-ATPase pump of the RCMs highlight the existence of additional mechanisms of QT prolongation by these antibiotics.en© 2024 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license.BedaquilineClofazimineCardiomyocytesCellular viabilitySodiumPotassium-adenosine triphosphataseAdenosine triphosphateMultidrug-resistant tuberculosis (MDR-TB)SDG-03: Good health and well-beingArticle