A Virus-Derived Immune Modulating Serpin Accelerates Wound Closure with Improved Collagen Remodeling.

Zhang Zhang,Yaron Yaron,Rege Rege,Wallace Wallace,Haydel Haydel,Lucas Lucas,Tafoya Tafoya,Mcfadden Mcfadden,Kilbourne Kilbourne

doi:10.3390/jcm8101626

Abstract

Numerous treatments have been developed to promote wound healing based on current understandings of the healing process. Hemorrhaging, clotting, and associated inflammation regulate early wound healing. We investigated treatment with a virus-derived immune modulating serine protease inhibitor (SERPIN), Serp-1, which inhibits thrombolytic proteases and inflammation, in a mouse excisional wound model. Saline or recombinant Serp-1 were applied directly to wounds as single doses of 1 μg or 2 µg or as two 1 µg boluses. A chitosan-collagen hydrogel was also tested for Serp-1 delivery. Wound size was measured daily for 15 days and scarring assessed by Masson’s trichrome, Herovici’s staining, and immune cell dynamics and angiogenesis by immunohistochemistry. Serp-1 treatment significantly accelerated wound healing, but was blocked by urokinase-type plasminogen activator (uPAR) antibody. Repeated dosing at a lower concentration was more effective than single high-dose serpin. A single application of Serp-1-loaded chitosan-collagen hydrogel was as effective as repeated aqueous Serp-1 dosing. Serp-1 treatment of wounds increased arginase-1-expressing M2-polarized macrophage counts and periwound angiogenesis in the wound bed. Collagen staining also demonstrated that Serp-1 improves collagen maturation and organization at the wound site. Serp-1 has potential as a safe and effective immune modulating treatment that targets thrombolytic proteases, accelerating healing and reducing scar in deep cutaneous wounds.

Highlights

Large surface wounds, including lacerations and burns, are common and often complex injuries
Treatment with urokinase-type plasminogen activator (uPAR) antibody alone or uPAR antibody given together with Serp-1 treatment resulted in identical healing curves indistinguishable from treatment with saline alone. These results indicate that the ability of Serp-1 to promote wound healing is dependent on uPAR
We report here that treatment with Serp-1, a purified myxoma virus-derived serine protease inhibitor (SERPIN) and immune modulating protein biologic, accelerates full thickness wound healing in wild-type mice

Summary

Introduction

Large surface wounds, including lacerations and burns, are common and often complex injuries. Comorbidities such as diabetes and advanced age cause skin lesions to turn into nonhealing chronic wounds, reducing function and increasing risk of infection and bleeding. Chronic nonhealing wounds can be life threatening and are a major threat to public health with a large economic burden [1,2]. According to the NIH ARRA Impact Report (https://report.nih.gov), over 6 million cases of chronic wounds occur annually in the United States with a collective cost of more than $20 billion per year. Severe burn injuries cause about 40,000 hospitalizations and nearly 4000 deaths each year. These numbers do not include scar revisions, which amount to over 170,000 procedures annually in the USA [3]. There is a substantial need and growing interest in developing new treatments to improve wound healing [4,5,6,7,8]

Results

Discussion

Conclusion