Abstract
<title>Abstract</title> <p> Background The actin-mitochondria interplay represents a fundamental regulatory axis that coordinates endothelial cell (EC) morphological changes and cellular stress responses. In severe malaria, proinflammatory cytokines dissolved in malaria patient sera may cause cytoskeletal and mitochondrial damage, thereby contributing to EC dysfunction. The study aims to investigate the morphological changes of ECs, and the relationship between actin cytoskeletal changes and mitochondrial alterations in ECs stimulated with different malaria patient sera. Methods ECs were grown and incubated with malaria patient sera ( <italic>P. vivax</italic> , <italic>P. falciparum</italic> both uncomplicated and complicated) at 0, 30, 60, and 90 min. Morphological changes of ECs upon contact with malaria patient sera were compared across experimental groups and control groups (complete media and non-malaria patient sera). The levels of tumor necrosis factor (TNF), interferon-gamma (IFN-γ), F-actin and G-actin were determined by Enzyme-Linked Immunosorbent Assay (ELISA). Mitochondria alterations were assessed using MitoTracker Green fluorescence and visualised by confocal microscope. Results Morphologically, significant EC changes of cellular shrinkage/contraction, increase in floating cells and widening of distance between cells were observed in ECs incubated with sera from complicated <italic>P. falciparum</italic> malaria patients. The lowest F-actin level and enhanced mitochondrial fragmentation were noted in ECs incubated with sera from severe malaria patients. Moreover, proinflammatory cytokines (TNF, IFN-γ) were inversely associated with F-actin levels and positively correlated with mitochondrial fragmentation. Conclusions Elevated levels of proinflammatory cytokines in severe malaria induced coordinated F-actin cytoskeletal and mitochondrial alterations. The findings highlight integrated actin-mitochondria functions and provide insight into severe malaria pathogenesis. In addition, the study supports the potential development of therapeutic strategy to restore damaged EC function during malaria infection. </p>