Alcaligenes faecalis corrects aberrant matrix metalloproteinase expression to promote re-epithelialization of diabetic wounds

Chronic wounds are a common and costly complication of diabetes, where multifactorial defects contribute to dysregulated skin repair, inflammation, tissue damage, and infection. We previously showed that aspects of the diabetic foot ulcer microbiota were correlated with poor healing outcomes, but many microbial species recovered remain uninvestigated with respect to wound healing. Here we focused onAlcaligenes faecalis, a Gram-negative bacterium that is frequently recovered from chronic wounds but rarely causes infection. Treatment of diabetic wounds withA. faecalisaccelerated healing during early stages. We investigated the underlying mechanisms and found thatA. faecalistreatment promotes re-epithelialization of diabetic keratinocytes, a process which is necessary for healing but deficient in chronic wounds. Overexpression of matrix metalloproteinases in diabetes contributes to failed epithelialization, and we found thatA. faecalistreatment balances this overexpression to allow proper healing. This work uncovers a mechanism of bacterial-driven wound repair and provides a foundation for the development of microbiota-based wound interventions. Overall design: Diabetic mouse wounds were treated with two different types of bacteria or vehicle control. At day 3, the skin was collected and processed for RNAsequencing. N = 4 mice per group