Activation of the pro-oxidant PKCβII-p66Shc signaling pathway contributes to pericyte dysfunction in skeletal muscles of diabetic patients with critical limb ischemia

COMPLICATIONS| SEPTEMBER 06 2016 Activation of the Pro-Oxidant PKCβII-p66Shc Signaling Pathway Contributes to Pericyte Dysfunction in Skeletal Muscles of Patients With Diabetes With Critical Limb Ischemia Rosa Vono; Claudia Fuoco; Stefano Testa; Stefano Pirrò; Davide Maselli; David Ferland McCollough; Elena Sangalli; Gianfranco Pintus; Roberta Giordo; Giovanna Finzi; Fausto Sessa; Rosanna Cardani; Ambra Gotti; Sergio Losa; Gianni Cesareni; Roberto Rizzi; Claudia Bearzi; Stefano Cannata; Gaia Spinetti; Cesare Gargioli; Paolo Madeddu Crossmark: Check for Updates Corresponding authors: Paolo Madeddu, paolo.madeddu@bristol.ac.uk, Cesare Gargioli, cesare.gargioli@uniroma2.it, and Gaia Spinetti, gaia.spinetti@multimedica.it. Diabetes 2016;65(12):3691–3704 https://doi.org/10.2337/db16-0248 Article history Split-Screen Views Icon Views PDF Share Icon Share Cite Icon Cite Get Permissions Critical limb ischemia (CLI), foot ulcers, former amputation, and impaired regeneration are independent risk factors for limb amputation in subjects with diabetes. The present work investigates whether and by which mechanism diabetes negatively impacts on functional properties of muscular pericytes (MPs), which are resident stem cells committed to reparative angiomyogenesis. We obtained muscle biopsy samples from patients with diabetes who were undergoing major limb amputation and control subjects. Diabetic muscles collected at the rim of normal tissue surrounding the plane of dissection showed myofiber degeneration, fat deposition, and reduction of MP vascular coverage. Diabetic MPs (D-MPs) display ultrastructural alterations, a differentiation bias toward adipogenesis at the detriment of myogenesis and an inhibitory activity on angiogenesis. Furthermore, they have an imbalanced redox state, with downregulation of the antioxidant enzymes superoxide dismutase 1 and catalase, and activation of the pro-oxidant protein kinase C isoform β-II (PKCβII)-dependent p66Shc signaling pathway. A reactive oxygen species scavenger or, even more effectively, clinically approved PKCβII inhibitors restore D-MP angiomyogenic activity. Inhibition of the PKCβII-dependent p66Shc signaling pathway could represent a novel therapeutic approach for the promotion of muscle repair in individuals with diabetes.