Nrf2/HO-1 partially regulates cytoprotective effects of carbon monoxide against urban particulate matter-induced inflammatory responses in oral keratinocytes

Ching-Yi Cheng; Thi Thuy Tien Vo; Wei-Ning Lin; Hsiang-Wei Huang; Chu-Chun Chuang; Pei-Ming Chu; I-Ta Lee

doi:10.1016/j.cyto.2020.155185

Nrf2/HO-1 partially regulates cytoprotective effects of carbon monoxide against urban particulate matter-induced inflammatory responses in oral keratinocytes

Cytokine. 2020 Sep:133:155185. doi: 10.1016/j.cyto.2020.155185. Epub 2020 Jun 29.

Authors

Ching-Yi Cheng¹, Thi Thuy Tien Vo², Wei-Ning Lin³, Hsiang-Wei Huang⁴, Chu-Chun Chuang⁵, Pei-Ming Chu⁶, I-Ta Lee⁷

Affiliations

¹ Graduate Institute of Health Industry Technology, Research Center for Chinese Herbal Medicine and Research Center for Food and Cosmetic Safety, Chang Gung University of Science and Technology, Taoyuan, Taiwan; Department of Pulmonary Infection and Immunology, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan.
² School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan.
³ Graduate Institute of Biomedical and Pharmaceutical Science, Fu Jen Catholic University, New Taipei City 242, Taiwan.
⁴ School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
⁵ International MS/PhD Program in Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
⁶ School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan.
⁷ School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan. Electronic address: itlee0128@tmu.edu.tw.

PMID: 32615411
DOI: 10.1016/j.cyto.2020.155185

Abstract

Introduction: Exposure to airborne particulate matter (PM) increases the proportion of oral inflammatory diseases. During the formation of inflammatory conditions, the nucleotide-binding domain and leucine-rich repeat protein 3 (NLRP3) inflammasome activation plays an important regulator. Carbon monoxide (CO) arising from heme degradation, catalyzed particularly by heme oxygenase-1 (HO-1), has been shown to own cytoprotective effects including anti-inflammation and antioxidant. Here, we determined the novel mechanisms of carbon monoxide releasing molecule-2 (CORM-2) on PM-induced inflammatory responses in human oral keratinocytes (HOKs).

Methods: The effects of CORM-2 on the expression of various inflammatory proteins induced by PM were determined by Western blot, real-time PCR, promoter assay, and ELISA. The involvement of signaling molecules in these responses was studied by using the selective pharmacological inhibitors and siRNAs.

Results: We proved that PM enhanced C-reactive protein (CRP) levels, NLRP3 inflammasome and caspase-1 activation, and IL-1β release, which were reduced by preincubation with CORM-2. Transfection with PKCα siRNA and preincubation with the ROS scavenger (N-acetyl-cysteine, NAC), an inhibitor of NADPH oxidase (diphenyleneiodonium, DPI), or the mitochondria-specific superoxide scavenger (MitoTEMPO) inhibited PM-mediated inflammatory responses. In addition, PM-regulated PKCα and NADPH oxidase activation as well as NADPH oxidase- and mitochondria-derived ROS generation were inhibited by CORM-2, but not inactivate CORM-2 (iCORM-2) pretreatment. At the end, we confirmed that CORM-2 improved PM-induced inflammatory responses via the induction of Nrf2 activation and HO-1 expression.

Conclusion: We suggest that CORM-2 inhibits PM-induced inflammatory responses in HOKs via the inhibition of PKCα/ROS/NLRP3 inflammasome activation combined with the induction of Nrf2/HO-1 expression.

Keywords: Carbon monoxide; NLRP3 inflammasome; Oral mucosal; Particulate matter; Reactive oxygen species.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Anti-Inflammatory Agents / pharmacology
Carbon Monoxide / pharmacology*
Cells, Cultured
Heme Oxygenase-1 / metabolism*
Humans
Inflammasomes / drug effects*
Inflammasomes / metabolism
Inflammation / chemically induced
Inflammation / metabolism
Keratinocytes / drug effects*
Keratinocytes / metabolism
Mitochondria / drug effects
Mitochondria / metabolism
NADPH Oxidases / metabolism
NF-E2-Related Factor 2 / metabolism*
Organometallic Compounds / pharmacology
Particulate Matter / pharmacology*
Protective Agents / pharmacology*
Reactive Oxygen Species / metabolism
Signal Transduction / drug effects

Substances

Anti-Inflammatory Agents
Inflammasomes
NF-E2-Related Factor 2
NFE2L2 protein, human
Organometallic Compounds
Particulate Matter
Protective Agents
Reactive Oxygen Species
tricarbonyldichlororuthenium (II) dimer
Carbon Monoxide
HMOX1 protein, human
Heme Oxygenase-1
NADPH Oxidases