G2A attenuates Propionibacterium acnes induction of inflammatory cytokines in human monocytes

Andrew J. Park, George W. Agak, Min Qin, Lisa D. Hisaw, Aslan Pirouz, Stephanie Kao, Laura J. Marinelli, Hermes J. Garbán, Diane Thiboutot, Philip T. Liu, Jenny Kim

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


Background: Acne vulgaris is a disease of the pilosebaceous unit characterized by increased sebum production, hyperkeratinization, and immune responses to Propionibacterium acnes (PA). Here, we explore a possible mechanism by which a lipid receptor, G2A, regulates immune responses to a commensal bacterium. Objective: To elucidate the inflammatory properties of G2A in monocytes in response to PA stimulation. Furthermore, our study sought to investigate pathways by which lipids modulate immune responses in response to PA. Methods: Our studies focused on monocytes collected from human peripheral blood mononuclear cells, the monocytic cell line THP-1, and a lab strain of PA. Our studies involved the use of enzyme-linked immunosorbent, Western blot, reverse transcription polymerase chain reaction, small interfering RNA (siRNA), and microarray analysis of human acne lesions in the measurements of inflammatory markers. Results: G2A gene expression is higher in acne lesions compared to normal skin and is inducible by the acne therapeutic, 13-cis-retinoic acid. In vitro, PA induces both the Toll-like receptor 2-dependent expression of G2A as well as the production of the G2A ligand, 9-hydroxyoctadecadienoic acid, from human monocytes. G2A gene knockdown through siRNA enhances PA stimulation of interleukin (IL)-6, IL-8, and IL-1β possibly through increased activation of the ERK1/2 MAP kinase and nuclear factor kappa B p65 pathways. Conclusion: G2A may play a role in quelling inflammatory cytokine response to PA, revealing G2A as a potential attenuator of inflammatory response in a disease associated with a commensal bacterium.

Original languageEnglish (US)
Pages (from-to)688-698
Number of pages11
JournalAnnals of Dermatology
Issue number6
StatePublished - Dec 2017

All Science Journal Classification (ASJC) codes

  • Dermatology


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