PKCδ inhibition normalizes the wound-healing capacity of diabetic human fibroblasts.

Abstract

Abnormal fibroblast function underlies poor wound healing in patients with diabetes; however, the mechanisms that impair wound healing are poorly defined. Here, we evaluated fibroblasts from individuals who had type 1 diabetes (T1D) for 50 years or more (Medalists, n = 26) and from age-matched controls (n = 7). Compared with those from controls, Medalist fibroblasts demonstrated a reduced migration response to insulin, lower VEGF expression, and less phosphorylated AKT (p-AKT), but not p-ERK, activation. Medalist fibroblasts were also functionally less effective at wound closure in nude mice. Activation of the δ isoform of protein kinase C (PKCδ) was increased in postmortem fibroblasts from Medalists, fibroblasts from living T1D subjects, biopsies of active wounds of living T1D subjects, and granulation tissues from mice with streptozotocin-induced diabetes. Diabetes-induced PKCD mRNA expression was related to a 2-fold increase in the mRNA half-life. Pharmacologic inhibition and siRNA-mediated knockdown of PKCδ or expression of a dominant-negative isoform restored insulin signaling of p-AKT and VEGF expression in vitro and improved wound healing in vivo. Additionally, increasing PKCδ expression in control fibroblasts produced the same abnormalities as those seen in Medalist fibroblasts. Our results indicate that persistent PKCδ elevation in fibroblasts from diabetic patients inhibits insulin signaling and function to impair wound healing and suggest PKCδ inhibition as a potential therapy to improve wound healing in diabetic patients.

• Authors: Mogher Khamaisi, Sayaka Katagiri, Hillary Keenan, Kyoungmin Park, Yasutaka Maeda, Qian Li, Weier Qi, Thomas Thomou, Danielle Eschuk, Ana Tellechea, Aris Veves, Chenyu Huang, Dennis Paul Orgill, Amy Wagers, George L King
• Journal: The Journal of clinical investigation (J Clin Invest) Vol. 126 Issue 3 Pg. 837-53 (Mar 01 2016) ISSN: 1558-8238 [Electronic] United States
• PMID: 26808499 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Insulin
• Protein Kinase Inhibitors
• VEGFA protein, human
• Vascular Endothelial Growth Factor A
• PRKCD protein, human
• Protein Kinase C-delta

Topics

• Aged
• Aged, 80 and over
• Animals
• Cell Hypoxia
• Cell Movement
• Cell Proliferation
• Cells, Cultured
• Diabetes Mellitus, Type 1 (complications, enzymology, pathology)
• Diabetic Foot (enzymology, pathology)
• Female
• Fibroblasts (physiology)
• Gene Knockdown Techniques
• Half-Life
• Humans
• Insulin (physiology)
• Male
• Mice, Nude
• Middle Aged
• Protein Kinase C-delta (antagonists & inhibitors, physiology)
• Protein Kinase Inhibitors (pharmacology)
• Vascular Endothelial Growth Factor A (metabolism)
• Wound Healing