Chao Liu1, Wei Ouyang1, Jingyan Xia2, Xiaoru Sun1, Liying Zhao1, Feng Xu1. 1. Department of Infectious Diseases, Zhejiang University School of Medicine, Hangzhou, China. 2. Department of Radiation Oncology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
Abstract
Background: Mast cells (MCs) play a key role in immune process response to invading pathogens. Methods: This study assessed the involvement of MCs in controlling Staphylococcus aureus infection in a cutaneous infection model of MC-deficient (KitW-sh/W-sh) mice. Results: KitW-sh/W-sh mice developed significantly larger skin lesions after the cutaneous S. aureus challenge, when compared to wild-type (WT) mice, while MC dysfunction reduced the inflammation response to S. aureus. The levels of tumor necrosis factor (TNF)-α in skin tissues were significantly decreased in KitW-sh/W-sh mice upon infection. Moreover, the exogenous administration of MCs or recombinant TNF-α effectively restored the immune response against S. aureus in KitW-sh/W-sh mice via the recruitment of neutrophils to the infected site. These results indicate that the effects of MC deficiency are largely attributed to the decrease in production of TNF-α in cutaneous S. aureus infection. In addition, S. aureus-induced MC activation was dependent on the c-kit receptor-activated phosphoinositide 3-kinase (PI3K)/AKT/P65-nuclear factor (NF-κB) pathway, which was confirmed by treatment with Masitinib (a c-kit receptor inhibitor), Wortmannin (a PI3K inhibitor), and pyrrolidine dithiocarbamate (a NF-κB inhibitor), respectively. Conclusions: The present study identifies the critical role of MCs in the host defense against S. aureus infection.
Background: Mast cells (MCs) play a key role in immune process response to invading pathogens. Methods: This study assessed the involvement of MCs in controlling Staphylococcus aureus infection in a cutaneous infection model of MC-deficient (KitW-sh/W-sh) mice. Results: KitW-sh/W-sh mice developed significantly larger skin lesions after the cutaneous S. aureus challenge, when compared to wild-type (WT) mice, while MC dysfunction reduced the inflammation response to S. aureus. The levels of tumor necrosis factor (TNF)-α in skin tissues were significantly decreased in KitW-sh/W-sh mice upon infection. Moreover, the exogenous administration of MCs or recombinant TNF-α effectively restored the immune response against S. aureus in KitW-sh/W-sh mice via the recruitment of neutrophils to the infected site. These results indicate that the effects of MC deficiency are largely attributed to the decrease in production of TNF-α in cutaneous S. aureus infection. In addition, S. aureus-induced MC activation was dependent on the c-kit receptor-activated phosphoinositide 3-kinase (PI3K)/AKT/P65-nuclear factor (NF-κB) pathway, which was confirmed by treatment with Masitinib (a c-kit receptor inhibitor), Wortmannin (a PI3K inhibitor), and pyrrolidine dithiocarbamate (a NF-κB inhibitor), respectively. Conclusions: The present study identifies the critical role of MCs in the host defense against S. aureus infection.