Detyrosinated microtubule arrays are associated with dysregulated reactive oxygen species and calcium signals in aging and dystrophic pathology

Post-translational modifications to tubulin regulate microtubule (MT) structure and function. Detyrosination is the cleavage of the terminal tyrosine from α-tubulin (deTyr-tubulin) by the enzyme complex of vasohibin (1 or 2) and the small vasohibin binding protein (VASH1/2-SVBP). Early evidence found MTs enriched in deTyr-tubulin regulated myogenic differentiation and our works in mature striated muscle found these MTs central to regulating cytoskeletal mechanics, mechanotransduction, and the maintenance of the myofibrillar structure. We find the proliferation of deTyr-enriched MTs is a conserved consequence in dystrophic and aging muscle that increases muscle fiber passive mechanics, mechanotransduction, and myofibrillar alterations that accelerate pathology. We now find similar changes in murine peripheral blood mononuclear cells (PBMCs) from aging and dystrophic mice and in THP-1 monocytes after lipopolysaccharide activation in keeping with inflammatory signaling as central to these changes. Our recent works sought to identify the signaling that underscores these conserved MT changes. Here we show that the stable overexpression of VASH 1 or 2 along with SVBP in C2C12 myoblasts (V1S, V2S) increases the homeostatic abundance of deTyr-MTs. Consistent with the elevated reactive oxygen species (ROS) and calcium (Ca 2+ ) central to aging and dystrophic pathology, we show that H2O2 efficiently increases the level of deTyr-MTs in Control C2C12s and in V1S and V2S cells, albeit to a lesser extent. We further demonstrate that either buffering cytosolic [Ca 2+ ] (BAPTA-AM) or inhibiting calcium-dependent calpain activity (Calpeptin) effectively reduced the level of deTyr-MTs in both untreated cells and those challenged with H2O2. These studies align with the premise that the excess ROS and calcium signals in aging and disease act through VASH to drive the proliferation of deTyr-enriched MTs. This work was supported with funds from NIH P30 AG028747-17 (JU, JS and CW), NIH R01 AR071618 (CW), and NIH (KP). This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.