Dermal adipocytes protect against invasive Staphylococcus aureus skin infection

Ling-juan Zhang, Christian F. Guerrero-Juarez, Tissa Hata,

Sagar P. Bapat, Raul Ramos, Maksim V. Plikus, Richard L. Gallo

Science 347(6217):67-71.

Speaker: Beatrice Lin (林怡慈)                        Time: 15:00~16:00, Mar.11, 2015

Commentator: Dr. Li-Jin Hsu (徐麗君老師)       Place: Room 601

Abstract:

The skin, which is composed of an outermost epidermis and an underlying dermis, represents an essential component of the innate immune system by limiting infiltration of foreign pathogens.To defend against rapid microbial infection, local resident cells such as epithelial cells, mast cells, and leukocytes will provide immediate protection before recruitment of additional cells [1]. In this study, the authors demonstrated that fat cells also play a part in the cellular response to bacterial infection. After exposing mice with Staphylococcus aureus, which is a major cause of skin and soft-tissue infection, the authors observed the rapid proliferation of preadipocytes and expansion of local dermal adipocytes that correlated with S. aureus clearance. To determine whether adipocyte activation was essential, the authors used different mouse models incapable of forming new fat cells, including mutation in the transcriptional factor Zfp423 (Zfp423^nur12) and pharmacological manipulation, and observed more severe infection by S. aureus. Further experiments showed that differentiating adipocytes defended against S. aureus infection through the production of the antimicrobial peptide, cathelicidin. However, mature fat cells produced less cathelicidin, and were thus less protective, which may explain observations of elevated susceptibility to infection during obesity [2]. In addition to its well-known role in growth and metabolism, this study demonstrates adipocytes play key roles in controlling skin and soft-tissue infection.

References:

1.         R. L. Gallo, L. V. Hooper. Epithelial antimicrobial defense of the skin and intestine. Nat. Rev. Immunol. (2012) 12, 503–516.

2.         W. P. Cawthorn, E. L. Scheller, O. A. MacDougald. Adipose tissue stem cells meet preadipocyte commitment: Going back to the future. J. Lipid Res. (2012) 53, 227–246.