Cell-free extracts of Propionibacterium acnes stimulate cytokine production through activation of p38 MAPK and Toll-like receptor in SZ95 sebocytes.
OBJECTIVE
Propionibacterium acnes has been considered to influence the acne lesions. The present study intended to elucidate the underlying signaling pathways of P. acnes in human sebaceous gland cells relative to the generation of proinflammatory cytokines.


METHODS
Cell-free extracts of P. acnes under stationary growth phase were co-incubated with human immortalized SZ95 sebocytes. Then, cell-free P. acnes extracts-induced cytokine expression was evaluated by measuring mRNA and protein levels using quantitative RT-PCR and ELISA. Changes of phosphorylated cell signaling proteins and transcription factors were measured by Western blots and Milliplex assay. The interactive molecular mechanisms of P. acnes and sebocytes were examined through use of shRNA and the specific inhibitors of signaling pathways.


RESULTS
Cell-free extracts of P. acnes significantly stimulated secretion of interleukin (IL)-8 and IL-6 in SZ95 sebocytes. The degradation of IκB-α and increased phosphorylation of IκB-α, p38 mitogen activated protein kinase (MAPK), CREB, and STAT3 were demonstrated. Quantitative RT-PCR measurements revealed that gene expression of IL-8 and Toll-like receptor 2 (TLR2) was enhanced by cell-free extracts of P. acnes. In addition, the NF-κB inhibitor BMS345541, p38 MAPK inhibitor SB203580, or anti-TLR2 neutralizing antibody prevented cell-free P. acnes extracts-induced secretion of IL-8. Knockdown of TLR2 using shRNA exerted similar inhibitory effects on IL-8 expression. Moreover, inhibition of STAT3 activity by STA-21 enhanced P. acnes-mediated secretion of IL-8.


CONCLUSIONS
Cell-free extracts of P. acnes are capable to activate NF-κB and p38 MAPK pathways and up-regulate secretion of IL-8 through TLR2-dependent signaling in human SZ95 sebocytes.
Department of Cosmetic Science, Providence University, No. 200, Sec. 7, Taiwan Boulevard, Shalu Dist., Taichung City 43301, Taiwan, ROC. Electronic address: ychuang@pu.edu.tw.
Yu-Chun
YC
Huang
Department of Cosmetic Science, Providence University, No. 200, Sec. 7, Taiwan Boulevard, Shalu Dist., Taichung City 43301, Taiwan, ROC.
Chao-Hsun
CH
Yang
Department of Cosmetic Science, Providence University, No. 200, Sec. 7, Taiwan Boulevard, Shalu Dist., Taichung City 43301, Taiwan, ROC.
Ting-Ting
TT
Li
Departments of Dermatology, Venereology, Allergology and Immunology, Dessau Medical Center, Auenweg 38, 06847 Dessau, Germany.
Christos C
CC
Zouboulis
Department of Cosmetic Science, Providence University, No. 200, Sec. 7, Taiwan Boulevard, Shalu Dist., Taichung City 43301, Taiwan, ROC.
Han-Chi
HC
Hsu
D000152:Acne Vulgaris / Q000276:immunology / Q000382:microbiology; D002460:Cell Line; D016207:Cytokines / Q000276:immunology; D006801:Humans; D016209:Interleukin-8 / Q000276:immunology*; D016328:NF-kappa B / Q000276:immunology*; D011425:Propionibacterium acnes / Q000276:immunology*; D012627:Sebaceous Glands / Q000166:cytology / Q000276:immunology / Q000382:microbiology*; D015398:Signal Transduction; D051195:Toll-Like Receptor 2 / Q000276:immunology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000276:immunology*
C508606:CXCL8 protein, human; D016207:Cytokines; D016209:Interleukin-8; D016328:NF-kappa B; D051195:Toll-Like Receptor 2; D048051:p38 Mitogen-Activated Protein Kinases
BMS345541 (PubChem CID: 9,926,054); Everolimus (PubChem CID: 6,442,177); LY294002 (PubChem CID: 3973); Proinflammatory cytokines; Propionibacterium acnes; SB203580 (PubChem CID: 176,155); SP600125 (PubChem CID: 8515); STA-21 (PubChem CID: 11,808,929); Sebocytes; Toll-like receptor; p38 Mitogen activated protein kinase