Abstract
Evidence from prior studies of cutaneous trauma, burns, and chronic diabetic wound repair demonstrates that endothelial progenitor cells (EPCs) contribute to de novo angiogenesis, anti-inflammatory reactions, tissue regeneration, and remodeling. We have shown that IL-10, a potent anti-inflammatory cytokine, promotes regenerative tissue repair in an adult model of dermal scar formation via the regulation of fibroblast-specific hyaluronan synthesis in a STAT3 dependent manner. While it is known that IL-10 drives EPC recruitment and neovascularization after myocardial infarction, its specific mode of action, particularly in dermal wound healing and neovascularization in both control and diabetic wounds remains to be defined. Here we show that IL-10 promotes EPC recruitment into the dermal wound microenvironment to facilitate neovascularization and wound healing of control and diabetic (db/db) wounds via vascular endothelial growth factor (VEGF) and stromal-cell derived factor 1 (SDF-1α) signaling. Inducible skin-specific STAT3 knockout (KO) mice were studied to determine whether the impact of IL-10 on the neovascularization and wound healing is STAT3 dependent. We found that IL-10 treatment significantly promotes dermal wound healing with enhanced wound closure, robust granulation tissue formation and neovascularization. This was associated with elevated wound EPC counts as well as increased VEGF and high SDF-1α levels in control mice, an effect that was abrogated in STAT3 KO transgenic mice. These findings were supported in vitro, wherein IL-10-enhanced VEGF and SDF-1α synthesis in primary murine dermal fibroblasts. IL-10-conditioned fibroblast media was shown to promote sprouting and network formation in aortic ring assays. We conclude that overexpression of IL-10 in the wound-specific milieu recruits EPCs and promote neovascularization, which occurs in a STAT3-dependent manner via regulation of VEGF and SDF-1α levels. Collectively, our studies demonstrate that IL-10 increases EPC recruitment leading to enhanced neovascularization and healing of dermal wounds.
Footnotes
The authors declare no competing financial interests.
List of abbreviations
- ΔΔCt
- Comparative Ct
- 4-OHT
- 4-hydroxy tamoxifen
- AFB
- Adult Fibroblasts
- ANOVA
- Analysis of Variance
- BGS
- Bovine Growth Serum
- BM
- Bone marrow
- CD34
- cluster of differentiation 34 molecule
- CD133
- cluster of differentiation 133 molecule (also known as Prominin1)
- CXCR4
- CXC chemokine receptor type 4
- DMEM
- Dulbecco’s Modified Eagle’s Media
- ECL
- Enhanced Chemoluminescence
- ECs
- Endothelial cells
- ECM
- Extracellular Matrix
- ELISA
- Enzyme-Linked Immunosorbent Assay
- EPCs
- Endothelial progenitor cells
- FLK-1
- Fetal Liver Kinase 1 (also known as KDR, is a receptor for VEGF)
- GFP
- Green Fluorescent Protein
- H&E
- Hematoxylin and Eosin
- HIF-1
- Hypoxia inducible factor 1
- HSCs
- Hematopoietic stem cells
- IgG
- Immunoglobulin G
- IHC
- Immunohistochemistry
- IL-10
- Interleukin 10
- IL-10R
- Interleukin 10 Receptor
- LV-GFP
- Lenti Virus expressing GFP
- LV-IL-10
- Lenti Virus expressing IL-10
- MI
- Myocardial Infarction
- PBS
- Phosphate Buffered Saline
- PSF
- Penicillin, Streptomycin, Amphotericin
- p-STAT3
- Phosphorylated Signal Transducer and Activator of Transcription 3
- qPCR
- Real Time-Polymerase Chain Reaction
- SDF-1α
- Stromal cell-derived factor 1α
- shRNA
- Short Hairpin RNA
- STAT3
- Signal Transducer and Activator of Transcription 3
- TBS
- Tris-Buffered Saline\
- TGF-β1, β3
- Transforming Growth Factor-β1, β3
- Tween-20
- Polysorbate-20
- VEGF
- Vascular endothelial growth factor