Leukocyte recruitment and molecular fortification of keratinocytes triggered by streptococcal M1 protein

Summary Streptococcus pyogenes of the M1 serotype is commonly associated with invasive streptococcal infections and development of streptococcal toxic shock syndrome. The M1 protein is a powerful inducer of inflammatory responses for several human cell types, but the reason why M1 protein‐related strains is over‐represented in invasive streptococcal diseases is still not understood. The present study was undertaken to investigate if soluble M1 protein can aggravate the severity of streptococcal skin infections in respect to inflammation, leukocyte recruitment, and tissue remodeling as seen in patients with cellulitis and necrotizing fasciitis. We found that HaCaT cells are able to recruit activated leukocytes when encountering M1 protein. Neither the bacterial protein nor activated leukocytes caused cell damage on HaCaT cells, instead HaCaT cells responded to the bacterial virulence factor by releasing several proteins protective against bacterial infection and leukocyte responses. However, although not cytotoxic, M1 protein completely abolished wound healing abilities of HaCaT cells. Taken together, our results demonstrate that M1 protein is a critical virulence factor that can augment streptococcal skin infection suggesting that the protein is an interesting target for drug development.
Source: Cellular Microbiology - Category: Microbiology Authors: Tags: RESEARCH ARTICLE Source Type: research