Microglial tunneling nanotubes: an intercellular transfer facilitating mitochondrial dysfunction and neuroinflammation in experimental cerebral malaria.

Cerebral malaria (CM), the most severe neurological manifestation of Plasmodium infection, is characterized by microglial activation that plays a pivotal role in initiating pathogenic neuroinflammatory cascades. Tunneling nanotubes (TNTs) are dynamic F-actin-based intercellular connections which transfer mitochondria and pathogenic factors. Although TNTs have been implicated in various neuropathological conditions, their precise involvement in CM pathogenesis, particularly in relation to microglial activation, remains undefined. In this study, single-cell RNA-sequencing (scRNA-seq) revealed significant dysregulation of TNT-associated genes and actin cytoskeleton pathway remodeling in microglia of ECM model. In vitro studies demonstrated that Plasmodium-infected red blood cells (pRBCs)-stimulated primary microglia formed extensive F-actin-rich tunneling nanotubes, which mediated the bidirectional transfer for mitochondria and facilitated intercellular trafficking of lysosomal contents and malarial pigment. These TNT-mediated intercellular communication amplified microglial activation, as evidenced by: (i) lipid peroxidation, (ii) mitochondrial dysfunction, and (iii) autophagosome (LC3