Biology subjects

Sinha, D. K.

Publications and source records attributed to Sinha, D. K..

3 recordsLinked to original sources

bioRxiv2026

Hydroxychloroquine alters the cytoskeleton to impair cell migration

Hydroxychloroquine (HCQ), a clinically relevant quinoline derivative, impairs both collective and individual cell migration by disrupting actin and vimentin cytoskeletal dynamics during wound healing. In scratch assays with HeLa cells, HCQ treatment significantly reduces wound closure rates and inhibits bursts of coordinated migration, as well as single-cell motility. Quantitative imaging reveals that HCQ diminishes actin filament density at the wound edge and induces reorganization of the vimentin network, resulting in smaller nuclei and compromised structural connectivity. Particle tracking micro-rheology demonstrates that HCQ softens the cytoplasm and decreases cellular mechanical heterogeneity. In vitro spectroscopic studies show that HCQ binds cooperatively to actin with micromolar affinity, perturbing its secondary structure, reducing filament polymerisation rates, and impairs interactions between actin and actin binding proteins (ABPs). HCQ also significantly suppresses lamellipodial protrusive activity, indicating a link between cytoskeletal remodelling and impaired cell migration. Collectively, these findings establish that HCQ disrupts essential mechanisms for directed migration by modulating the cytoskeleton and cell mechanics. This multifaceted impairment may underlie therapeutic potential of HCQ as an anticancer agent by restricting cellular invasive capacity and remodelling required for tumour progression.

cell biology↗

bioRxiv2022

Piezo1 mechanosensing regulates integrin-dependent chemotactic migration in human T cells

T cells are crucial for efficient antigen-specific immune responses and thus their migration within the body, to inflamed tissues from circulating blood or to secondary lymphoid organs, play a very critical role. T cell extravasation in inflamed tissues depends on chemotactic cues and interaction between endothelial adhesion molecules and cellular integrins. A migrating T cell is expected to sense diverse external and membrane-intrinsic mechano-physical cues, but molecular mechanisms of such mechanosensing in cell migration are not established. We explored if the professional mechanosensor Piezo1 play any role during integrin-dependent chemotaxis of human T cells. We found that deficiency of Piezo1 in human T cells interfered with integrin-dependent cellular motility on ICAM-1-coated surface. Piezo1 recruitment at the leading edge of moving T cells is dependent on and follows focal adhesion formation at the leading edge and local increase in membrane tension on chemokine receptor activation. Piezo1 recruitment and activation, followed by calcium influx and calpain activation, in turn are crucial for the integrin LFA-1 (CD11a/CD18) recruitment at the leading edge of the chemotactic human T cells. Thus, we find that Piezo1 activation in response to local mechanical cues constitutes a membrane-intrinsic component of the outside-in signaling in human T cells, migrating in response to chemokines, that mediates integrin recruitment to the leading edge.

immunology↗

bioRxiv2019

Interplay of bacterial membrane vesicle and host lipid physicochemical parameters during host-bacterial membrane vesicle interaction

Bacterial membrane vesicles (MVs) facilitate long-distance delivery of virulence factors crucial for pathogenicity. The entry and trafficking mechanisms of virulence factors inside host cells are recently emerging, however, if bacterial MVs can fuse and modulate the physicochemical properties of the host lipid membrane and membrane lipid parameter for fusion remains unknown. Here we reconstitute the interaction of bacterial MV with host cell lipid membranes and quantitatively show that bacterial MV interaction increases the fluidity, dipole potential, and Compressibility of a biologically relevant multi-component host membrane upon fusion. The presence of cylindrical lipids such as phosphatidylcholine and a moderate acyl chain length of C16 helps the MV interaction. While significant binding of bacterial MVs to the raft-like lipid membranes with phase-separated regions of the membrane was observed, however, MVs prefer binding to the liquid-disordered regions of the membrane. Further, the elevated levels of cholesterol tend to hinder the interaction of bacterial MVs as evident from the favorable excess Gibbs free energy of mixing of bacterial MVs with host lipid membranes. The findings provide new insights that might have implications for the regulation of host machinery by bacterial pathogens through the manipulation of host membrane properties.

biochemistry↗