14S,21R-Dihydroxydocosahexaenoic Acid Remedies Impaired Healing and Mesenchymal Stem Cell Functions in Diabetic Wounds

Abstract

Treatment of diabetes-impaired wound healing remains a major unresolved medical challenge. Here, we identified suppressed formation of a novel reparative lipid mediator 14S,21R-dihydroxydocosa-4Z,7Z,10Z,12E,16Z,19Z-hexaenoic acid (14S,21R-diHDHA) in cutaneous wounds of diabetic db/db mice. These results indicate that diabetes impedes the biosynthetic pathways of 14S,21R-diHDHA in skin wounds. Administration of exogenous 14S,21R-diHDHA to wounds in diabetic animals rescued healing and angiogenesis. When db/db mesenchymal stem cells (MSCs) were administered together with 14S,21R-diHDHA to wounds in diabetic animals, they coacted to accelerate wound re-epithelialization, granulation tissue formation, and synergistically improved vascularization. In the pivotal cellular processes of angiogenesis, 14S,21R-diHDHA enhanced VEGF release, vasculature formation, and migration of db/db dermal microvascular endothelial cells (DMVECs), as well as remedied paracrine angiogenic functions of db/db MSCs, including VEGF secretion and the promotion of DMVEC migration and vasculature formation. Our results show that 14S,21R-diHDHA activates the p38 MAPK pathway in wounds, db/db MSCs, and DMVECs. Overall, the impeded formation of 14S,21R-diHDHA described in this study suggests that diabetes could affect the generation of pro-healing lipid mediators in wound healing. By restoring wound healing and MSC functions, 14S,21R-diHDHA is a new lead for the development of better therapeutics used in treating wounds of diabetics.

Autacoid 14S,21R-Dihydroxy-Docosahexaenoic Acid Counteracts Diabetic Impairment of Macrophage Prohealing Functions

“…Dermal microvascular endothelial cells (DMVECs) were isolated from skin of db/db mice and confirmed by immunocytochemical analysis, which demonstrated their purity (Ͼ95%) based on the staining of endothelial markers CD31 (red) and VE-cadherin (green); nuclei were stained with Hoechst 33342 blue dye (see Supplemental Figure S1B at http://ajp.amjpathol.org). 16 Human peripheral blood provided by the New Orleans Blood Bank was collected from a code-deidentified healthy donor who had not taken medication for 2 weeks before donation. Blood was also collected by cardiac puncture from C57BL/6J mice under deep anesthesia.…”

“…16,30,31 Briefly, paired 5-mm circular, full-thickness wounds were made symmetrically along the midline on the dorsal skin of mice. Two days later, 14S,21R-diHDHA (50 ng/wound) or macrophages and 14S,21R-diHDHAtreated macrophages (10 6 cells/wound) were applied to the wound bed (10 L/bed) and were injected intradermally at four points (10 L/site) distributed evenly near the wound edge (50 L total/wound).…”

“…The DHA-derived lipid mediator neuroprotectin D1 (NPD1; 10R,17S-dihydroxydocosa-4Z,7Z,11E,13E,15Z,19Z-hexaenoic acid) enhances corneal wound healing, 15 and 14S,21R-dihydroxydocosa-4Z,7Z,10Z,12E,16Z,19Z-hexaenoic acid (14S,21R-diHDHA), a novel endogenous DHA-derived lipid mediator, is generated by macrophages and in wounded skin. 8,16 14S,21R-diHDHA is produced by sequential enzymatic actions of 14S-hydroperoxylation-specific leukocyte-12-lipoxygenase (L-12-LOX) and -1-hydroxylation-specific P450. 8 When applied to wounds, 14S,21R-diHDHA potently promotes healing and angiogenesis in wounds.…”

“…8 When applied to wounds, 14S,21R-diHDHA potently promotes healing and angiogenesis in wounds. 8,16 Diabetes and the accompanying hyperglycemia and oxidative stress damage DNA, proteins, and lipids in various tissues. These conditions cause cellular and enzymatic dysfunction during the formation of cytokines and eicosanoids associated with cell growth, angiogenesis, and/or inflammation, 4,7,[17][18][19] all of which are at least in part responsible for impairment of macrophage functions in diabetes.…”

“…18,19 We have observed that 14S,21R-diHDHA formation was significantly halted in diabetic wounds, compared with nondiabetic wounds in mice, which suggests that diabetic complications dysregulate the generation of DHA-derived lipid mediators. 16 In addition, supplementation of 14S,21R-diHDHA into diabetic wounds counteracts diabetes-associated impairment of wound healing, 16 indicating that 14S,21R-diHDHA is an important prohealing lipid mediator. Also, decreased 14S,21R-diHDHA formation in diabetes may affect prohealing functions of cells that participate in wound healing.…”