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Pathophysiological concentrations of hydrogen peroxide and glutamate increase tunneling nanotube formation in cad and hela cells
Discovered in 2004, tunneling nanotubes (TNTs) are actin-based, bridge-like structures that allow the intercellular transport of cellular components, electrical signals, and pathogens. Thus, TNTs have been implicated in viral propagation, neurodegenerative diseases, and cancer. Most research has focused on examining the molecules within cells that aid in TNT formation and function, but little has been documented on the role that exogenous molecules have in TNT formation. Past research has determined that hydrogen peroxide (H2O2) induces TNTs in various cell lines; however, the amount of H2O2 used was above was high (100μM). The aim of this study was to establish if TNT formation can be induced by pathophysiological H2O2 concentrations. In addition, we also investigated glutamate, an inducer of actin-based filopodia in astrocytes, as a possible TNT inducer. The data obtained using fluorescence microcopy suggest that low concentrations of H2O2 and glutamate are able to increase TNTs in both HeLa and CAD cell lines. Furthermore, cells treated with low concentrations of H2O2 or glutamate showed an increase in the expression of Myo10, a protein that has been linked to TNT formation and function. Lastly, the data obtained with a microscope capillary single cell sorting system suggest that H2O2 and glutamate can induce the formation as well as the elongation of cellular protrusions in distances ranging from 14-96 μm. Altogether, these results provide useful insights regarding TNT formation pathways in cells as well as the exogenous molecules involved in the formation of TNTs.