Astroglia proliferate upon biogenesis of tunneling nanotubes and clearance of α-synuclein toxicities

Astrocytic cells are a subtype of glial cells that engulf pathogenic aggregates derived from degenerative neurons to facilitate its degradation. Here, we show that exposure to -SYN protofibrils caused a transient increase in biogenesis of tunneling nanotubes (TNTs) in primary astrocytes and astrocyte-origin cancer cell-lines (U-87 MG, U251). Biogenesis of nascent TNTs corresponds to -SYN protofibril-induced organelle toxicities, increased reactive oxygen species (ROS), and oxidative stress-induced premature cellular senescence. These TNTs mediate cell-to-cell transfer of -SYN protofibrils, toxic lysosomes and mitochondria. Biogenesis of TNTs precedes clearance of -SYN-induced organelle toxicities, cellular ROS levels and reversal of cellular senescence. Consequences of cellular clearance results in enhanced cell proliferation. Further, we have shown -SYN-induced senescence promotes transient localization of focal adhesion kinase (FAK) in the nucleus. FAK mediated regulation of Rho-associated kinases may have a role in the biogenesis of TNTs, successively proliferation. Our study emphasizes that TNT biogenesis may have a potential role in the clearance of -SYN toxicities and reversal of stress-induced cellular senescence, consequences of which cause enhanced proliferation in the post-recovered astroglia cells. HighlightsO_LI-SYN protofibrils treated astroglia cells proliferate upon transient biogenesis of TNTs. C_LIO_LITransient TNT biogenesis precedes clearance of -SYN toxicities and reversal of senescence. C_LIO_LIStress-induced senescence results in nuclear localization of FAK and ROCK mediated TNT biogenesis. C_LIO_LIThe rescued cells enhance proliferation through ROCK mediated ERK1/2 and NF{kappa}B signalling cascades. C_LI Synopsis O_FIG O_LINKSMALLFIG WIDTH=167 HEIGHT=200 SRC="FIGDIR/small/554645v1_figa1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@9dc5bcorg.highwire.dtl.DTLVardef@20e924org.highwire.dtl.DTLVardef@aa7920org.highwire.dtl.DTLVardef@1f6274b_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical Abstract:C_FLOATNO -SYN protofibrils-induced biogenesis of tunneling nanotubes (TNTs) aids to enhance cellular clearance of toxic burdens as a cellular survival strategy. -SYN protofibrils treated toxic senescence cells regulate FAK mediated modulation of ROCK signalling cascades to promote TNT biogenesis and rescue the cellular toxicities. The rescued cells eventually enhance cell proliferation. C_FIG