Topical small molecule\xa0granzyme B\xa0inhibitor improves remodeling in a\xa0murine model of impaired burn wound healing

Yue Shen,Rachel Huang,Sho Hiroyasu,Hongyan Zhao,James B Jaquith ,Matthew R Zeglinski,Layla Nabai,Steve Arns,Anthony Papp,Richard Liggins,Haishan Zeng,Sheetal A Raithatha,Anthony Boey,Kathryn Westendorf,Irina Kopko,Zhenguo Wu,Valerio Russo,Cameron Oram,Tatjana Bozin,Cathy Turner ,Dale R Cameron,Jia Tan ,David J Granville

doi:10.1038/s12276-018-0095-0

Abstract

Granzyme B (GzmB) is a serine protease that has long been thought to function exclusively in lymphocyte-mediated apoptosis. In recent years, this paradigm has been revisited due to the recognition that GzmB accumulates in the extracellular milieu in many autoimmune and chronic inflammatory disorders, and contributes to impaired tissue remodeling due to the cleavage of extracellular matrix proteins. Knockout studies suggest that GzmB-mediated cleavage of decorin (DCN) contributes to impaired collagen fibrillogenesis and remodeling. As DCN is anti-fibrotic and contributes to reduced hypertrophic scarring, GzmB-induced DCN cleavage could play a role in wound healing following burn injury. In the present study, a novel, gel-formulated, first-in-class small-molecule inhibitor of GzmB, VTI-1002, was assessed in a murine model of impaired, diabetic burn wound healing. VTI-1002 exhibited high specificity, potency, and target selectivity. Gel-formulated VTI-1002 was able to penetrate the stratum corneum and was retained in the skin with minimal systemic absorption. Daily topical administration of VTI-1002 gel for 30 days following thermal injury showed significantly accelerated wound closure, increased DCN protein levels, and collagen organization that was translated into significantly increased wound tensile strength compared to controls. Overall, VTI-1002 gel was well-tolerated in vivo and no adverse events were observed. Topical application of VTI-1002 represents a novel therapeutic approach for the treatment of cutaneous burn wounds.

Highlights

Chronic, non-healing wounds are unable to progress through the normal, tightly regulated sequelae of overlapping stages of hemostasis, inflammation, granulation tissue formation, and remodeling
A critical challenge for teasing out the individual activities of Granzyme B (GzmB) and caspase-8 is the lack of specificity in available inhibitors
To assess specificity for human GzmB, VTI-1002 was tested against numerous relevant proteases, including caspases 3–10, cathepsin G, and neutrophil elastase (Table 1)

Summary

Introduction

Non-healing wounds are unable to progress through the normal, tightly regulated sequelae of overlapping stages of hemostasis, inflammation, granulation tissue formation, and remodeling. In many cases, delayed healing can be attributed to sustained inflammation and the excessive release of factors such as proteolytic enzymes that prevent re-epithelialization, de novo tissue formation, and/or wound remodeling. Chronic wounds are often associated with aging, immobility, obesity, and/ or diabetes[1]. Up to 2% of the population in developed countries will experience a chronic wound during their lifetime[2]. It is estimated that treatment of chronic wounds cost US$6 to US$15 billion annually in the United States[3]. Current treatment of chronic wounds is largely underdeveloped and it still mainly comprises of conventional

Methods

Results

Conclusion