Helminth TGF-β mimic, TGM, increases leukocyte migration and activation while also enhancing cutaneous wound healing and tissue regeneration.

Abstract

Abstract Intestinal parasites express excretory/secretory (ES) molecules, which modulate the type-2 immune response including anti-inflammatory and tissue repair mechanisms. TGF-β mimic (TGM), an ES molecule secreted by Heligmosomoides polygyrus (Hp), binds TGF-β receptors yet lacks structural homology to TGF-β and distinct receptor interactions. We now demonstrate that TGM enhanced wound healing using an in vivo wound biopsy model in which TGM, in a 1.5% carboxymethylcellulose solution, was topically administered beneath a Tegaderm layer. Through histological analysis, greater restoration of normal tissue structure in the wound beds of TGM treated mice was observed during mid to late stage wound healing. These observations included accelerated re-epithelialization as well as hair follicle regeneration, in the absence of increased scarring. Using flow cytometric, histological and gene expression analyses, differential expansion of myeloid populations at different stages of wound healing was observed. This included enhanced early accumulation and persistence of migratory Ly6C+ macrophages in TGM-treated wounds during the early inflammatory phase. Additionally, at mid-stage wound healing, we observed increased CD301b+ myeloid populations, a subset that is critical to efficient tissue restoration. In summary, TGM can enhance skin wound healing and associated recruitment of specific macrophage subsets and elevation of type 2 cytokines. This study indicates a role for TGM as a potential novel therapeutic option for enhanced wound healing.