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Takanezawa Y, Ishikawa K, Nakayama S, Nakamura R, Ohshiro Y, Uraguchi S, Kiyono M. Conversion of methylmercury into inorganic mercury via organomercurial lyase (MerB) activates autophagy and aggresome formation. Sci Rep 2023; 13:19958. [PMID: 37968352 PMCID: PMC10651920 DOI: 10.1038/s41598-023-47110-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 11/09/2023] [Indexed: 11/17/2023] Open
Abstract
Methylmercury (MeHg) is converted to inorganic mercury (iHg) in several organs; however, its impact on tissues and cells remains poorly understood. Previously, we established a bacterial organomercury lyase (MerB)-expressing mammalian cell line to overcome the low cell permeability of iHg and investigate its effects. Here, we elucidated the cytotoxic effects of the resultant iHg on autophagy and deciphered their relationship. Treatment of MerB-expressing cells with MeHg significantly increases the mRNA and protein levels of LC3B and p62, which are involved in autophagosome formation and substrate recognition, respectively. Autophagic flux assays using the autophagy inhibitor chloroquine (CQ) revealed that MeHg treatment activates autophagy in MerB-expressing cells but not in wild-type cells. Additionally, MeHg treatment induces the accumulation of ubiquitinated proteins and p62, specifically in MerB-expressing cells. Confocal microscopy revealed that large ubiquitinated protein aggregates (aggresomes) associated with p62 are formed transiently in the perinuclear region of MerB-expressing cells upon MeHg exposure. Meanwhile, inhibition of autophagic flux decreases the MeHg-induced cell viability of MerB-expressing cells. Overall, our results imply that cells regulate aggresome formation and autophagy activation by activating LC3B and p62 to prevent cytotoxicity caused by iHg. These findings provide insights into the role of autophagy against iHg-mediated toxicity.
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Affiliation(s)
- Yasukazu Takanezawa
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| | - Kouhei Ishikawa
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| | - Shunsuke Nakayama
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| | - Ryosuke Nakamura
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| | - Yuka Ohshiro
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| | - Shimpei Uraguchi
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| | - Masako Kiyono
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan.
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Katakia YT, Thakkar NP, Thakar S, Sakhuja A, Goyal R, Sharma H, Dave R, Mandloi A, Basu S, Nigam I, Kuncharam BVR, Chowdhury S, Majumder S. Dynamic alterations of H3K4me3 and H3K27me3 at ADAM17 and Jagged-1 gene promoters cause an inflammatory switch of endothelial cells. J Cell Physiol 2021; 237:992-1012. [PMID: 34520565 DOI: 10.1002/jcp.30579] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 08/25/2021] [Accepted: 08/28/2021] [Indexed: 01/01/2023]
Abstract
Histone protein modifications control the inflammatory state of many immune cells. However, how dynamic alteration in histone methylation causes endothelial inflammation and apoptosis is not clearly understood. To examine this, we explored two contrasting histone methylations; an activating histone H3 lysine 4 trimethylation (H3K4me3) and a repressive histone H3 lysine 27 trimethylation (H3K27me3) in endothelial cells (EC) undergoing inflammation. Through computer-aided reconstruction and 3D printing of the human coronary artery, we developed a unique model where EC were exposed to a pattern of oscillatory/disturbed flow as similar to in vivo conditions. Upon induction of endothelial inflammation, we detected a significant rise in H3K4me3 caused by an increase in the expression of SET1/COMPASS family of H3K4 methyltransferases, including MLL1, MLL2, and SET1B. In contrast, EC undergoing inflammation exhibited truncated H3K27me3 level engendered by EZH2 cytosolic translocation through threonine 367 phosphorylation and an increase in the expression of histone demethylating enzyme JMJD3 and UTX. Additionally, many SET1/COMPASS family of proteins, including MLL1 (C), MLL2, and WDR5, were associated with either UTX or JMJD3 or both and such association was elevated in EC upon exposure to inflammatory stimuli. Dynamic enrichment of H3K4me3 and loss of H3K27me3 at Notch-associated gene promoters caused ADAM17 and Jagged-1 derepression and abrupt Notch activation. Conversely, either reducing H3K4me3 or increasing H3K27me3 in EC undergoing inflammation attenuated Notch activation, endothelial inflammation, and apoptosis. Together, these findings indicate that dynamic chromatin modifications may cause an inflammatory and apoptotic switch of EC and that epigenetic reprogramming can potentially improve outcomes in endothelial inflammation-associated cardiovascular diseases.
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Affiliation(s)
- Yash T Katakia
- Department of Biological Sciences, Birla Institute of Technology and Science (BITS), Pilani Campus, Pilani, India
| | - Niyati P Thakkar
- Department of Biological Sciences, Birla Institute of Technology and Science (BITS), Pilani Campus, Pilani, India
| | - Sumukh Thakar
- Department of Biological Sciences, Birla Institute of Technology and Science (BITS), Pilani Campus, Pilani, India
| | - Ashima Sakhuja
- Department of Biological Sciences, Birla Institute of Technology and Science (BITS), Pilani Campus, Pilani, India
| | - Raghav Goyal
- Department of Biological Sciences, Birla Institute of Technology and Science (BITS), Pilani Campus, Pilani, India
| | - Harshita Sharma
- Department of Biological Sciences, Birla Institute of Technology and Science (BITS), Pilani Campus, Pilani, India
| | - Rakshita Dave
- Department of Biological Sciences, Birla Institute of Technology and Science (BITS), Pilani Campus, Pilani, India
| | - Ayushi Mandloi
- Department of Biological Sciences, Birla Institute of Technology and Science (BITS), Pilani Campus, Pilani, India
| | - Sayan Basu
- Department of Biological Sciences, Birla Institute of Technology and Science (BITS), Pilani Campus, Pilani, India
| | - Ishan Nigam
- Department of Biological Sciences, Birla Institute of Technology and Science (BITS), Pilani Campus, Pilani, India
| | - Bhanu V R Kuncharam
- Department of Chemical Engineering, Birla Institute of Technology and Science (BITS), Pilani Campus, Pilani, India
| | - Shibasish Chowdhury
- Department of Biological Sciences, Birla Institute of Technology and Science (BITS), Pilani Campus, Pilani, India
| | - Syamantak Majumder
- Department of Biological Sciences, Birla Institute of Technology and Science (BITS), Pilani Campus, Pilani, India
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Eliyahu E, Tirosh O, Dobesova M, Nachshon A, Schwartz M, Stern-Ginossar N. Rho-Associated Coiled-Coil Kinase 1 Translocates to the Nucleus and Inhibits Human Cytomegalovirus Propagation. J Virol 2019; 93:e00453-19. [PMID: 31292242 PMCID: PMC6744247 DOI: 10.1128/jvi.00453-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 06/29/2019] [Indexed: 01/04/2023] Open
Abstract
Rho-associated coiled-coil kinase (ROCK) protein is a central kinase that regulates numerous cellular functions, including cellular polarity, motility, proliferation, and apoptosis. Here, we demonstrate that ROCK has antiviral properties, and inhibition of its activity results in enhanced propagation of human cytomegalovirus (HCMV). We show that during HCMV infection, ROCK1 translocates to the nucleus and concentrates in the nucleolus, where it colocalizes with the stress-related chaperone heat shock cognate 71-kDa protein (Hsc70). Gene expression measurements show that inhibition of ROCK activity does not seem to affect the cellular stress response. We demonstrate that inhibition of myosin, one of the central targets of ROCK, also increases HCMV propagation, implying that the antiviral activity of ROCK might be mediated by activation of the actomyosin network. Finally, we demonstrate that inhibition of ROCK results in increased levels of the tegument protein UL32 and of viral DNA in the cytoplasm, suggesting ROCK activity hinders the efficient egress of HCMV particles out of the nucleus. Altogether, our findings illustrate ROCK activity restricts HCMV propagation and suggest this inhibitory effect may be mediated by suppression of capsid egress out of the nucleus.IMPORTANCE ROCK is a central kinase in cells that regulates numerous cellular functions, including cellular polarity, motility, proliferation, and apoptosis. Here we reveal a novel antiviral activity of ROCK during infection with HCMV, a prevalent pathogen infecting most of the population worldwide. We reveal ROCK1 is translocated to the nucleus, where it mainly localizes to the nucleolus. Our findings suggest that ROCK's antiviral activity may be related to activation of the actomyosin network and inhibition of capsid egress out of the nucleus.
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Affiliation(s)
- Erez Eliyahu
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Osnat Tirosh
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Martina Dobesova
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Aharon Nachshon
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Michal Schwartz
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Noam Stern-Ginossar
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
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