title: Glycolic Acid Silences Inflammasome Complex Genes, NLRC4 and ASC, by Inducing DNA Methylation in HaCaT Cells.
abstract: AHAs (α-hydroxy acids), including glycolic acid (GA), have been widely used in cosmetic products and superficial chemical peels. Inflammasome complex has been shown to play critical roles in inflammatory pathways in human keratinocytes. However, the anti-inflammatory mechanism of GA is still unknown. The aim of this study is to investigate the relationship between the expression of the inflammasome complex and epigenetic modification to elucidate the molecular mechanism of the anti-inflammatory effect of GA in HaCaT cells. We evaluated NLRP3, NLRC4, AIM2, and ASC inflammasome complex gene expression on real-time polymerase chain reaction (PCR). Methylation changes were detected in these genes following treatment with DNA methyltransferase (DNMT) inhibitor 5-aza-2'-deoxycytidine (5-Aza) with or without the addition of GA using methylation-specific PCR (MSP). GA inhibited the expressions of these inflammasome complex genes, and the decreases in the expressions of mRNA were reversed by 5-Aza treatment. Methylation was detected in NLRC4 and ASC on MSP, but not in NLRP3 or AIM2. GA decreased NLRC4 and ASC gene expression by increasing not only DNA methyltransferase 3B (DNMT-3B) protein level, but also total DNMT activity. Furthermore, silencing of DNMT-3B (shDNMT-3B) increased the expressions of NLRC4 and ASC. Our data demonstrated that GA treatment induces hypermethylation of promoters of NLRC4 and ASC genes, which may subsequently lead to the hindering of the assembly of the inflammasome complex in HaCaT cells. These results highlight the anti-inflammatory potential of GA-containing cosmetic agents in human skin cells and demonstrate for the first time the role of aberrant hypermethylation in this process.
authors.affiliation: 1 Department of Biochemistry, School of Medicine, Tzu Chi University , Hualien, Taiwan .|2 Institute of Biomedical Sciences , Academia Sinica, Taipei, Taiwan .
authors.forename: Sheau-Chung
authors.initials: SC
authors.lastname: Tang
authors.affiliation: 3 Institute of Medicine, College of Medicine, Tzu Chi University , Hualien, Taiwan .|4 Department of Family Medicine, Buddhist Tzu Chi General Hospital , Hualien, Taiwan .
authors.forename: Jih-I
authors.initials: JI
authors.lastname: Yeh
authors.affiliation: 3 Institute of Medicine, College of Medicine, Tzu Chi University , Hualien, Taiwan .|5 Department of Dermatology, Buddhist Tzu Chi General Hospital , Hualien, Taiwan .
authors.forename: Sung-Jen
authors.initials: SJ
authors.lastname: Hung
authors.affiliation: 6 Institute of Medicine, College of Medicine, Chung Shan Medical University , Taichung, Taiwan .|7 Department of Dermatology, Chung Shan Medical University Hospital , Taichung, Taiwan .
authors.forename: Yu-Ping
authors.initials: YP
authors.lastname: Hsiao
authors.affiliation: 2 Institute of Biomedical Sciences , Academia Sinica, Taipei, Taiwan .|8 Department of Dermatology, University of California Davis School of Medicine , Sacramento, California.
authors.forename: Fu-Tong
authors.initials: FT
authors.lastname: Liu
authors.affiliation: 1 Department of Biochemistry, School of Medicine, Tzu Chi University , Hualien, Taiwan .|3 Institute of Medicine, College of Medicine, Tzu Chi University , Hualien, Taiwan .|5 Department of Dermatology, Buddhist Tzu Chi General Hospital , Hualien, Taiwan .
authors.forename: Jen-Hung
authors.initials: JH
authors.lastname: Yang
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology; D053468:CARD Signaling Adaptor Proteins / Q000235:genetics*; D002135:Calcium-Binding Proteins / Q000235:genetics*; D002460:Cell Line / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D003598:Cytoskeletal Proteins / Q000235:genetics*; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D019175:DNA Methylation / Q000187:drug effects*; D000077209:Decitabine; D044127:Epigenesis, Genetic; D005786:Gene Expression Regulation / Q000187:drug effects; D006016:Glycolates / Q000494:pharmacology*; D006801:Humans; D058847:Inflammasomes / Q000187:drug effects / Q000235:genetics*; D015603:Keratinocytes / Q000187:drug effects / Q000502:physiology; D011401:Promoter Regions, Genetic / Q000187:drug effects; D034622:RNA Interference; D000097584:DNA Methyltransferase 3B
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D001374:Azacitidine; D053468:CARD Signaling Adaptor Proteins; D002135:Calcium-Binding Proteins; D003598:Cytoskeletal Proteins; D004248:DNA (Cytosine-5-)-Methyltransferases; D000077209:Decitabine; D006016:Glycolates; D058847:Inflammasomes; D000097584:DNA Methyltransferase 3B; C435692:NLRC4 protein, human; C402202:PYCARD protein, human; C031149:glycolic acid