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Sawai M, Miyauchi Y, Ishida T, Takechi S. Dihydropyrazine suppresses TLR4-dependent inflammatory responses by blocking MAPK signaling in human hepatoma HepG2 cells. J Toxicol Sci 2022; 47:381-387. [PMID: 36047112 DOI: 10.2131/jts.47.381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Dihydropyrazines (DHPs), including 3-hydro-2,2,5,6-tetramethylpyrazine (DHP-3), are glycation products generated through non-enzymatic reactions in vivo and in food. They are recognized as compounds that are toxic to organisms as they produce radicals. However, our previous study indicated that DHP-3 suppressed Toll-like receptor 4 (TLR4) expression and decreased the phosphorylation of nuclear factor-κB (NF-κB) in lipopolysaccharide (LPS)-treated HepG2 cells. TLR4 signaling is involved in the onset of various inflammatory diseases, and NF-κB and mitogen-activated protein kinase (MAPK) play important roles in TLR4 signaling. Thus, we aimed to elucidate the effects of DHP-3 on MAPK signaling and in turn on the activated TLR4 signaling pathway. In LPS-stimulated HepG2 cells, DHP-3 reduced the phosphorylation of MAPK, extracellular signal-regulated kinase, c-Jun NH2-terminal kinase, and p38. The expression of c-jun, a subunit of activator protein-1, was decreased by DHP-3 treatment. Furthermore, DHP-3-induced suppression of MAPK signaling resulted in a decrease in various inflammatory regulators, such as interleukin-6, CC-chemokine ligand 2, and cyclooxygenase-2. These results suggest that DHP-3 exerts an inhibitory effect on TLR4-dependent inflammatory response by suppressing MAPK signaling.
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Affiliation(s)
- Madoka Sawai
- School of Pharmacy at Fukuoka, International University of Health and Welfare
| | - Yuu Miyauchi
- Faculty of Pharmaceutical Sciences, Sojo University
| | - Takumi Ishida
- School of Pharmacy at Fukuoka, International University of Health and Welfare
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Huang H, Chang YH, Xu J, Ni HY, Zhao H, Zhai BW, Efferth T, Gu CB, Fu YJ. Aucubin as a natural potential anti-acute hepatitis candidate: Inhibitory potency and hepatoprotective mechanism. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2022; 102:154170. [PMID: 35609387 DOI: 10.1016/j.phymed.2022.154170] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 04/17/2022] [Accepted: 05/12/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Hepatic inflammation can substantially impact the development of acute hepatitis. It is a pressing need to identify and exploit novel therapeutic targets as well as effective drug therapies against acute hepatitis. Aucubin (AU) is one of the main active components extracted from the leaves of Eucommia ulmoides and possesses significant anti-inflammatory and antioxidant activities. However, the protective effect and mechanism of AU on acute hepatitis have not been reported yet. PURPOSE This study aims to investigate the protective effect of AU on LPS-induced acute hepatitis and the mechanism of action. METHODS The limma package was used to analyze differentially expressed genes (DEGs) between LPS-induced acute hepatitis and normal groups based on Gene Expression Omnibus (GEO) microarray data. Network pharmacology predicted targets for AU therapy against acute hepatitis, and Gene Ontology (GO) enrichment analysis of the biological processes involved in these targets. The key pathways were analyzed by protein-protein interaction, KEGG (Kyoto Encyclopedia of Genes and Genomes), and GSEA (Gene Set Enrichment Analysis) enrichment. The important interaction targets between AU and key pathways were evaluated by molecular simulation. The in silico predicted mechanism was verified based on in vitro and in vivo experiments. RESULTS A total of 116 intersection targets between AU prediction targets and differentially expressed genes were identified. They were functionally involved in the imbalance of "inflammation-anti-inflammation" and "oxidation-antioxidation" systems in the process of LPS-induced cases. In vitro experiments revealed that AU reduced inflammation in LPS-induced HepG2 cells by reducing the inflammatory cytokines TNF-α, IL-6, as well as iNOS enzyme activity levels. In addition, LPS-induced oxidative stress can be alleviated by AU via adjusting the levels of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), Malone dialdehyde (MDA) and reactive oxygen species (ROS). Protein-protein interaction and GSEA results showed that AU might exert anti-inflammatory effects mainly through the STAT3/NF-κB signal pathway. Molecular dynamics simulation as well as in vivo tests further demonstrated AU restrained nuclear transfer of NF-κB (P65), probably through reducing phosphorylation of STAT3. In addition, AU appears to reduce oxidative stress by upregulating NRF2/HO-1. CONCLUSION We explored potential targets and signal pathways of AU in inhibiting acute hepatitis. AU exerted anti-inflammatory and antioxidant activities and may be a useful candidate drug for the treatment of acute hepatitis.
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Affiliation(s)
- Han Huang
- Key Laboratory of Forest Plant Ecology, Ministry of Education, Northeast Forestry University, Harbin 150040, China; Engineering Research Center of Forest Bio-Preparation, Ministry of Education, Northeast Forestry University, Harbin 150040, PR China; College of Chemistry, Chemical Engineering and Resource Utilization, Northeast Forestry University, Harbin 150040, China
| | - Yuan-Hang Chang
- Key Laboratory of Forest Plant Ecology, Ministry of Education, Northeast Forestry University, Harbin 150040, China; Engineering Research Center of Forest Bio-Preparation, Ministry of Education, Northeast Forestry University, Harbin 150040, PR China; College of Chemistry, Chemical Engineering and Resource Utilization, Northeast Forestry University, Harbin 150040, China
| | - Jian Xu
- Key Laboratory of Forest Plant Ecology, Ministry of Education, Northeast Forestry University, Harbin 150040, China; Engineering Research Center of Forest Bio-Preparation, Ministry of Education, Northeast Forestry University, Harbin 150040, PR China; College of Chemistry, Chemical Engineering and Resource Utilization, Northeast Forestry University, Harbin 150040, China
| | - Hai-Yan Ni
- Key Laboratory of Forest Plant Ecology, Ministry of Education, Northeast Forestry University, Harbin 150040, China; Engineering Research Center of Forest Bio-Preparation, Ministry of Education, Northeast Forestry University, Harbin 150040, PR China; College of Chemistry, Chemical Engineering and Resource Utilization, Northeast Forestry University, Harbin 150040, China
| | - Heng Zhao
- Key Laboratory of Forest Plant Ecology, Ministry of Education, Northeast Forestry University, Harbin 150040, China; Engineering Research Center of Forest Bio-Preparation, Ministry of Education, Northeast Forestry University, Harbin 150040, PR China; College of Chemistry, Chemical Engineering and Resource Utilization, Northeast Forestry University, Harbin 150040, China
| | - Bo-Wen Zhai
- Department of Pharmaceutical Biology, Institute of Pharmaceutical and Biomedical Sciences, University of Mainz, 55128, Mainz, Germany
| | - Thomas Efferth
- Department of Pharmaceutical Biology, Institute of Pharmaceutical and Biomedical Sciences, University of Mainz, 55128, Mainz, Germany
| | - Cheng-Bo Gu
- Key Laboratory of Forest Plant Ecology, Ministry of Education, Northeast Forestry University, Harbin 150040, China; Engineering Research Center of Forest Bio-Preparation, Ministry of Education, Northeast Forestry University, Harbin 150040, PR China; College of Chemistry, Chemical Engineering and Resource Utilization, Northeast Forestry University, Harbin 150040, China.
| | - Yu-Jie Fu
- The College of Forestry, Beijing Forestry University, Beijing 100083, China.
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Miyauchi Y, Sawai M, Ishida T, Kansui H, Takechi S. Molecular mechanism of dihydropyrazine-induced cytotoxicity: the possibility of an independent pathway from the receptor for advanced glycation end products. J Toxicol Sci 2021; 46:509-514. [PMID: 34719553 DOI: 10.2131/jts.46.509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Dihydropyrazines (DHPs) are one of glycation products that are non-enzymatically generated in vivo and in food. We had previously revealed that 3-hydro-2,2,5,6-tetramethylpyrazine (DHP-3), a methyl-substituted DHP, elicited redox imbalance and cytotoxicity in cultured cells. However, the molecular mechanisms underlying DHP-3-induced cytotoxicity remain unclear. To address this issue, we examined the involvement of the receptor for advanced glycation end products (RAGE) in DHP-3-induced cytotoxicity. To evaluate the role of RAGE, we prepared HeLa cells that constitutively expressed RAGE and its deletion mutant, which lacks the cytoplasmic domain (RAGEΔcyto), using an episomal vector. After transfection with the vector, cells were selected following incubation with multiple concentrations of hygromycin to remove non-transfected cells. The expression of RAGE and RAGEΔcyto in the cells was confirmed by immunoblotting. RAGE and RAGEΔcyto were apparently expressed in transfected cells; however, there were no significant differences in DHP-3-induced cytotoxicity between these cells and mock vector-transfected cells. These results suggested that DHP-3 elicits cytotoxicity in a RAGE-independent manner.
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Affiliation(s)
- Yuu Miyauchi
- Laboratory of Hygienic Chemistry, Faculty of Pharmaceutical Sciences, Sojo University
| | - Madoka Sawai
- International University of Health and Welfare, School of Pharmacy at Fukuoka
| | - Takumi Ishida
- International University of Health and Welfare, School of Pharmacy at Fukuoka
| | - Hisao Kansui
- Laboratory of Organic Chemistry, Faculty of Pharmaceutical Sciences, Sojo University
| | - Shinji Takechi
- Laboratory of Hygienic Chemistry, Faculty of Pharmaceutical Sciences, Sojo University
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