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Inoue E, Minatozaki S, Shimizu S, Miyamoto S, Jo M, Ni J, Tozaki-Saitoh H, Oda K, Nonaka S, Nakanishi H. Human β-Defensin 3 Inhibition of P. gingivalis LPS-Induced IL-1β Production by BV-2 Microglia through Suppression of Cathepsins B and L. Cells 2024; 13:283. [PMID: 38334675 PMCID: PMC10854704 DOI: 10.3390/cells13030283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Revised: 01/30/2024] [Accepted: 02/01/2024] [Indexed: 02/10/2024] Open
Abstract
Cathepsin B (CatB) is thought to be essential for the induction of Porphyromonas gingivalis lipopolysaccharide (Pg LPS)-induced Alzheimer's disease-like pathologies in mice, including interleukin-1β (IL-1β) production and cognitive decline. However, little is known about the role of CatB in Pg virulence factor-induced IL-1β production by microglia. We first subjected IL-1β-luciferase reporter BV-2 microglia to inhibitors of Toll-like receptors (TLRs), IκB kinase, and the NLRP3 inflammasome following stimulation with Pg LPS and outer membrane vesicles (OMVs). To clarify the involvement of CatB, we used several known CatB inhibitors, including CA-074Me, ZRLR, and human β-defensin 3 (hBD3). IL-1β production in BV-2 microglia induced by Pg LPS and OMVs was significantly inhibited by the TLR2 inhibitor C29 and the IκB kinase inhibitor wedelolactonne, but not by the NLRPs inhibitor MCC950. Both hBD3 and CA-074Me significantly inhibited Pg LPS-induced IL-1β production in BV-2 microglia. Although CA-074Me also suppressed OMV-induced IL-1β production, hBD3 did not inhibit it. Furthermore, both hBD3 and CA-074Me significantly blocked Pg LPS-induced nuclear NF-κB p65 translocation and IκBα degradation. In contrast, hBD3 and CA-074Me did not block OMV-induced nuclear NF-κB p65 translocation or IκBα degradation. Furthermore, neither ZRLR, a specific CatB inhibitor, nor shRNA-mediated knockdown of CatB expression had any effect on Pg virulence factor-induced IL-1β production. Interestingly, phagocytosis of OMVs by BV-2 microglia induced IL-1β production. Finally, the structural models generated by AlphaFold indicated that hBD3 can bind to the substrate-binding pocket of CatB, and possibly CatL as well. These results suggest that Pg LPS induces CatB/CatL-dependent synthesis and processing of pro-IL-1β without activation of the NLRP3 inflammasome. In contrast, OMVs promote the synthesis and processing of pro-IL-1β through CatB/CatL-independent phagocytic mechanisms. Thus, hBD3 can improve the IL-1β-associated vicious inflammatory cycle induced by microglia through inhibition of CatB/CatL.
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Affiliation(s)
- Erika Inoue
- Faculty of Pharmacy, Yasuda Women’s University, Hiroshima 731-0153, Japan; (E.I.); (S.M.); (S.S.); (S.M.); (M.J.)
| | - Shiyo Minatozaki
- Faculty of Pharmacy, Yasuda Women’s University, Hiroshima 731-0153, Japan; (E.I.); (S.M.); (S.S.); (S.M.); (M.J.)
| | - Sachi Shimizu
- Faculty of Pharmacy, Yasuda Women’s University, Hiroshima 731-0153, Japan; (E.I.); (S.M.); (S.S.); (S.M.); (M.J.)
| | - Sayaka Miyamoto
- Faculty of Pharmacy, Yasuda Women’s University, Hiroshima 731-0153, Japan; (E.I.); (S.M.); (S.S.); (S.M.); (M.J.)
| | - Misato Jo
- Faculty of Pharmacy, Yasuda Women’s University, Hiroshima 731-0153, Japan; (E.I.); (S.M.); (S.S.); (S.M.); (M.J.)
| | - Junjun Ni
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, Beijing 100081, China;
| | - Hidetoshi Tozaki-Saitoh
- Department of Pharmaceutical Sciences, School of Pharmacy at Fukuoka, International University of Health and Welfare, Okawa 831-8501, Japan;
| | - Kosuke Oda
- Department of Pharmacology, Faculty of Pharmacy, Yasuda Women’s University, Yasuhigashi, Hiroshima 731-0153, Japan; (K.O.); (S.N.)
| | - Saori Nonaka
- Department of Pharmacology, Faculty of Pharmacy, Yasuda Women’s University, Yasuhigashi, Hiroshima 731-0153, Japan; (K.O.); (S.N.)
| | - Hiroshi Nakanishi
- Department of Pharmacology, Faculty of Pharmacy, Yasuda Women’s University, Yasuhigashi, Hiroshima 731-0153, Japan; (K.O.); (S.N.)
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Inoue E, Minatozaki S, Katsuta Y, Nonaka S, Nakanishi H. Human β-Defensin 3 Inhibits Porphyromonas Gingivalis Lipopolysaccharide-Induced Oxidative and Inflammatory Responses of Microglia by Suppression of Cathepsins B and L. Int J Mol Sci 2022; 23:ijms232315099. [PMID: 36499428 PMCID: PMC9738813 DOI: 10.3390/ijms232315099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 11/25/2022] [Accepted: 11/29/2022] [Indexed: 12/03/2022] Open
Abstract
Recently, the effects of antibacterial peptides are suggested to have therapeutic potential in Alzheimer's disease. Furthermore, systemic treatment of Porphyromonas gingivalis (Pg) lipopolysaccharide (LPS) induced Alzheimer's disease-like neuropathological changes in middle-aged mice. Then, we examined whether human β-defensins (hBDs), antimicrobial peptides produced by the oral mucosa and salivary glands, can suppress Pg LPS-induced oxidative and inflammatory responses by microglia. hBD3 (1 μM) significantly suppressed Pg LPS-induced production of nitric oxide and interleukin-6 (IL-6) by MG6 cells, a mouse microglial cell line. hBD3 (1 μM) also significantly inhibited Pg LPS-induced expression of IL-6 by HMC3 cells, a human microglial cell line. In contrast, neither hBD1, hBD2 nor hBD4 failed to inhibit their productions. Furthermore, hBD3 suppressed Pg LPS-induced p65 nuclear translocation through the IκBα degradation. Pg LPS-induced expression of IL-6 was significantly suppressed by E64d, a cysteine protease inhibitor, and CA-074Me, a known specific inhibitor for cathepsin B, but not by pepstatin A, an aspartic protease inhibitor. Interestingly, hBD3 significantly inhibited enzymatic activities of recombinant human cathepsins B and L, lysosomal cysteine proteases, and their intracellular activities in MG6 cells. Therefore, hBD3 suppressed oxidative and inflammatory responses of microglia through the inhibition of cathepsins B and L, which enzymatic activities are necessary for the NF-κB activation.
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Affiliation(s)
- Erika Inoue
- Faculty of Pharmacy, Yasuda Women’s University, Hiroshima 731-0153, Japan
| | - Shiyo Minatozaki
- Faculty of Pharmacy, Yasuda Women’s University, Hiroshima 731-0153, Japan
| | - Yui Katsuta
- Faculty of Pharmacy, Yasuda Women’s University, Hiroshima 731-0153, Japan
| | - Saori Nonaka
- Department of Pharmacology, Faculty of Pharmacy, Yasuda Women’s University, Hiroshima 731-0153, Japan
| | - Hiroshi Nakanishi
- Department of Pharmacology, Faculty of Pharmacy, Yasuda Women’s University, Hiroshima 731-0153, Japan
- Correspondence:
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