School of Medicine and Health Sciences Poster Presentations

Title

PARP-1 Silencing Upregulates FOSL1 Transcription, Enhances Angiogenesis And Accelerates Ischemic-Diabetic Wound Healing

Poster Number

154

Document Type

Poster

Status

Postdoc

Abstract Category

Clinical Specialties

Keywords

wound healing, diabetes, angiogenesis

Publication Date

Spring 2018

Abstract

Objective: People with combined ischemic and diabetic wounds of the lower extremities have the highest risk for limb loss, especially for those without surgical revascularization options. Better medical therapy to enhance angiogenesis is needed for limb salvage. We have demonstrated that Poly-ADP-Ribose polymerase (PARP-1) is hyperactivated in hyperglycemic/hypoxic (Hg/Hp) cells and in ischemic/diabetic murine wounds. This study tests the efficacy of PARP-1 inhibition or silencing in ischemic-diabetic wound healing and further elucidates the role of PARP-1 in angiogenesis.

Methods: A model of dorsal bipedicle flap-ischemic wounds on diabetic mice was used. The wounds were treated topically with nanoparticle-encapsulated siPARP-1 or vehicle. Wound closure rate and perfusion was analyzed using digital photography and Laser Doppler scanning, respectively. Angiogenetic markers in the tissues were measured by immunohistochemistry. In-vitro endothelial tube formation assay was performed using HUVECs cultured under hyperglycemic and hypoxic conditions.

Results: Wounds treated with topical siPARP-1 significantly accelerated wound healing compared to vehicle (from 25% ± 5% to 40%± 8% (n=7, p < .05) by day 6 and from 50% ± 15% to 75%± 3% (n=7, p < .05) by day 12, and also exhibited improved tissue perfusion (50%± 5% increase in perfusion units over control on day 6, n=47 p <0.05). Improved capillary density was also observed in the siPARP-1 treated wounds detected by immunohistochemistry for SMA (250%±35% increase in mean fluorescence intensity over control on day 12, n=4, p<0.05) and CD31 (125% ± 15% increase in mean fluorescence intensity over control on day 12, n=4, p<0.05). In-vitro angiogenesis assay showed that PARP-1-silencing significantly enhanced endothelial tube formation of hyperglycemic/hypoxic HUVECs (15± 4 complete polygons as compared to 0 in untreated, n=4, p<0.05). Human angiogenesis PCR-array analysis of pro-angiogenic factors revealed that PARP-1 silencing upregulated FOSL1 transcription by 5-fold (n=4, p<0.05). Interestingly, co-silencing of FOSL1 in PARP-1 silenced HUVECs resulted in loss of endothelial tube formation.

Conclusions: PARP-1 silencing is an effective strategy to promote ischemic-diabetic wound healing. Our data suggest that PARP-1-FOSL1 is a potential novel axis in angiogenesis and PARP-1 could be a promising therapeutic target for improving angiogenesis in ischemic-diabetic wounds.

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Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

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PARP-1 Silencing Upregulates FOSL1 Transcription, Enhances Angiogenesis And Accelerates Ischemic-Diabetic Wound Healing

Objective: People with combined ischemic and diabetic wounds of the lower extremities have the highest risk for limb loss, especially for those without surgical revascularization options. Better medical therapy to enhance angiogenesis is needed for limb salvage. We have demonstrated that Poly-ADP-Ribose polymerase (PARP-1) is hyperactivated in hyperglycemic/hypoxic (Hg/Hp) cells and in ischemic/diabetic murine wounds. This study tests the efficacy of PARP-1 inhibition or silencing in ischemic-diabetic wound healing and further elucidates the role of PARP-1 in angiogenesis.

Methods: A model of dorsal bipedicle flap-ischemic wounds on diabetic mice was used. The wounds were treated topically with nanoparticle-encapsulated siPARP-1 or vehicle. Wound closure rate and perfusion was analyzed using digital photography and Laser Doppler scanning, respectively. Angiogenetic markers in the tissues were measured by immunohistochemistry. In-vitro endothelial tube formation assay was performed using HUVECs cultured under hyperglycemic and hypoxic conditions.

Results: Wounds treated with topical siPARP-1 significantly accelerated wound healing compared to vehicle (from 25% ± 5% to 40%± 8% (n=7, p < .05) by day 6 and from 50% ± 15% to 75%± 3% (n=7, p < .05) by day 12, and also exhibited improved tissue perfusion (50%± 5% increase in perfusion units over control on day 6, n=47 p <0.05). Improved capillary density was also observed in the siPARP-1 treated wounds detected by immunohistochemistry for SMA (250%±35% increase in mean fluorescence intensity over control on day 12, n=4, p<0.05) and CD31 (125% ± 15% increase in mean fluorescence intensity over control on day 12, n=4, p<0.05). In-vitro angiogenesis assay showed that PARP-1-silencing significantly enhanced endothelial tube formation of hyperglycemic/hypoxic HUVECs (15± 4 complete polygons as compared to 0 in untreated, n=4, p<0.05). Human angiogenesis PCR-array analysis of pro-angiogenic factors revealed that PARP-1 silencing upregulated FOSL1 transcription by 5-fold (n=4, p<0.05). Interestingly, co-silencing of FOSL1 in PARP-1 silenced HUVECs resulted in loss of endothelial tube formation.

Conclusions: PARP-1 silencing is an effective strategy to promote ischemic-diabetic wound healing. Our data suggest that PARP-1-FOSL1 is a potential novel axis in angiogenesis and PARP-1 could be a promising therapeutic target for improving angiogenesis in ischemic-diabetic wounds.