John Libbey Eurotext

European Journal of Dermatology


Formalin-killed Propionibacterium acnes activates the aryl hydrocarbon receptor and modifies differentiation of SZ95 sebocytes in vitro Volume 31, numéro 1, January-February 2021


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1 Department of Dermatology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, PR China
2 Department of Immunology and Microbiology, School of Medicine, Shanghai Jiaotong University, Shanghai, PR China
3 Department of Dermatology and Allergy, Technical University of Munich, Munich, Germany
4 Department of Dermatology, Huashan Hospital, Fudan University, Shanghai, PR China
5 Departments of Dermatology, Venereology, Allergology and Immunology, Dessau Medical Center, Brandenburg Medical School Theodor Fontane, Dessau, Germany
* Reprints
a These authors contributed equally

Background: Acne vulgaris is a common pilosebaceous disease associated with Propionibacterium acnes (P. acnes). Resolution of comedones may occur in association with shrunken sebaceous glands (SGs) containing de-differentiated cells, however the role of P. acnes is unclear. Objectives: To investigate the effects of P. acnes on aryl hydrocarbon receptor (AhR) activation, lipogenesis and differentiation in cultured immortalized human SZ95 sebocytes. Materials & Methods: Cultured sebocytes were incubated with formalin-killed (f-) P. acnes (f-P. acnes) at different ratios of multiplicity of infection. The mRNA levels of the AhR downstream cytochrome P450 (CYP) genes were measured by quantitative RT-PCR, nuclear translocation of AhR by western blot and immunofluorescence, lipogenesis and keratinization by gene set enrichment analysis (GSEA), lipid related analysis by Oil red O staining and Nile red staining, and sebaceous differentiation-related gene expression by western blot. Results: f-P. acnes upregulated CYPs mRNA levels and induced translocation of AhR protein from the cytoplasm into the nucleus. GSEA revealed downregulation of lipogenesis and upregulation of keratinization. f-P. acnes inhibited linoleic acid-induced neutral lipid synthesis and expression of sebocyte markers, keratin 7 and mucin1/EMA, but increased expression of keratinocyte markers, keratin 10 and involucrin, which were abolished by AhR gene silencing. Inhibition of lipogenesis-related genes, such as sterol response element-binding protein, was also observed. Conclusion: f-P. acnes inhibits lipogenesis and induces terminal differentiation of sebocytes, into keratinocyte-like cells, via activation of the AhR pathway in vitro, suggesting that follicular P. acnes is not only acnegenic but also promotes acne remission through feedback regulation of sebum production.