Abstract 16752: Restoration of Defective Hydrogen Sulfide Production in Bone Marrow Cells From Diabetic Mice Rescues Their Impaired Tissue Reparative Function

Background: Bone marrow cell (BMC)-based treatment for critical limb ischemia (CLI) in diabetic patients yielded a modest therapeutic effect due to cell dysfunction. Therefore, approaches that improve diabetic BMC function may provide therapeutic benefits. Here, we tested the hypotheses that restoration of hydrogen sulfide (H 2 S) production in diabetic BMCs improves their reparative capacities. Methods and Results: Both H 2 S production and cystathionine γ-lyase (CSE), an H 2 S enzyme, levels were significantly decreased in BMCs from diabetic db/db mice. Administration of H 2 S donor diallyl trisulfide (DATS) or overexpression of CSE restored H 2 S production and enhanced cell survival and migratory capacity in high glucose (HG)-treated BMCs. Left hind limb ischemia (HLI) surgery was conducted in db/+ and db/db mice followed by oral administration of DATS and/or local intramuscular injection of GFP-labeled BMCs or CSE-overexpressed BMCs by transfection of GFP lentivirus or RFP-tagged CSE lentivirus (CSE-BMCs). BMCs were isolated from db/db mice. Mice with HLI were divided into six groups: 1) db/+; 2) db/db; 3) db/db+BMCs; 4) db/db+DATS; 5) db/db+DATS+BMCs; 6) db/db+CSE-BMCs. DATS and CSE overexpression greatly enhanced diabetic BMCs retention in ischemic hind limbs (IHL) followed by improved blood perfusion, capillary/arteriole density, skeletal muscle architecture and cell survival, and decreased perivascular CD68 + cell infiltration in IHL of diabetic mice. Interestingly, DATS or CSE overexpression rescued HG-impaired migration, tube formation and survival of BMCs or mature human cardiac microvascular endothelial cells (HCMVECs). Mechanistically, DATS restored nitric oxide production and decreased eNOS-pT495 levels in HCMVECs, and improved BMC angiogenic activity under HG condition. Finally, silencing CSE by siRNA significantly increased eNOS-pT495 levels in HCMVECs. Conclusions: Decreased CSE-mediated H 2 S bioavailability is an underlying source of BMC dysfunction in diabetes. Our data indicate that H 2 S and overexpression of CSE in diabetic BMCs may rescue their dysfunction and open novel avenues for cell-based therapeutics of CLI in diabetic patients.