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Yang CH, Li HC, Ku TS, Wu PC, Yeh YJ, Cheng JC, Lin TY, Lo SY. Hepatitis C virus down-regulates SERPINE1/PAI-1 expression to facilitate its replication. J Gen Virol 2017; 98:2274-2286. [PMID: 28857040 DOI: 10.1099/jgv.0.000901] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Identification of host factors involved in viral replication is critical for understanding the molecular mechanism of viral replication and pathogenesis. Genes differentially expressed in HuH-7 cells with or without a hepatitis C virus (HCV) sub-genomic replicon were screened by microarray analysis. SERPINE1/PAI-1 was found to be down-regulated after HCV infection in this analysis. Down-regulation of SERPINE1/PAI-1 expression at the transcriptional level was verified by the real-time reverse transcriptase (RT)-PCR assay. Reduced SERPINE1/PAI-1 protein secretion was detected in the supernatant of HCV replicon cells and in sera from HCV-infected patients. SERPINE1 gene expression was down-regulated by HCV NS3/4A and NS5A proteins through the transforming growth factor-β (TGF-β) signalling pathway at the transcriptional level. Down-regulated genes in HCV replicon cells could be the factors supressing HCV replication. Indeed, over-expressed PAI-1 inhibited HCV replication but the mechanism is unknown. It has been demonstrated that HCV induces the expression of TGF-β, and TGF-β enhances HCV replication by a not-yet-defined mechanism. SERPINE1/PAI-1 is also known to be potently induced by TGF-β at the transcriptional level through both Smad-dependent and Smad-independent pathways. The exogenously expressed SERPINE1/PAI-1 suppressed the expression of the endogenous SERPINE1 gene at the transcriptional level through the TGF-β signalling but not the Smad pathway. Thus, SERPINE1/PAI-1 could suppress HCV replication possibly by negatively regulating TGF-β signalling. A model is proposed for the interplay betweenthe TGF-β signalling pathway, HCV and SERPINE1/PAI-1 to keep the homeostasis of the cells.
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Affiliation(s)
- Chee-Hing Yang
- Institute of medical Sciences, Tzu Chi University, Hualien, Taiwan, ROC
| | - Hui-Chun Li
- Department of Biochemistry, School of Medicine, Tzu Chi University, Hualien, Taiwan, ROC
| | - Tzu-Shan Ku
- Department of Laboratory Medicine and Biotechnology, Tzu Chi University, Hualien, Taiwan, ROC
| | - Pi-Ching Wu
- Department of Laboratory Medicine and Biotechnology, Tzu Chi University, Hualien, Taiwan, ROC
| | - Yung-Ju Yeh
- Department of Medical Laboratory Science and Biotechnology, China Medical University, Taichung, Taiwan, ROC
| | - Ju-Chien Cheng
- Department of Medical Laboratory Science and Biotechnology, China Medical University, Taichung, Taiwan, ROC
| | - Teng-Yi Lin
- Department of Laboratory Medicine, Buddhist Tzu Chi General Hospital, Hualien, Taiwan, ROC
| | - Shih-Yen Lo
- Department of Laboratory Medicine and Biotechnology, Tzu Chi University, Hualien, Taiwan, ROC.,Department of Laboratory Medicine, Buddhist Tzu Chi General Hospital, Hualien, Taiwan, ROC.,Institute of medical Sciences, Tzu Chi University, Hualien, Taiwan, ROC
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Chen JS, Li HC, Lin SI, Yang CH, Chien WY, Syu CL, Lo SY. Cleavage of Dicer protein by I7 protease during vaccinia virus infection. PLoS One 2015; 10:e0120390. [PMID: 25815818 PMCID: PMC4376780 DOI: 10.1371/journal.pone.0120390] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 01/21/2015] [Indexed: 11/18/2022] Open
Abstract
Dicer is the key component in the miRNA pathway. Degradation of Dicer protein is facilitated during vaccinia virus (VV) infection. A C-terminal cleaved product of Dicer protein was detected in the presence of MG132 during VV infection. Thus, it is possible that Dicer protein is cleaved by a viral protease followed by proteasome degradation of the cleaved product. There is a potential I7 protease cleavage site in the C-terminus of Dicer protein. Indeed, reduction of Dicer protein was detected when Dicer was co-expressed with I7 protease but not with an I7 protease mutant protein lack of the protease activity. Mutation of the potential I7 cleavage site in the C-terminus of Dicer protein resisted its degradation during VV infection. Furthermore, Dicer protein was reduced dramatically by recombinant VV vI7Li after the induction of I7 protease. If VV could facilitate the degradation of Dicer protein, the process of miRNA should be affected by VV infection. Indeed, accumulation of precursor miR122 was detected after VV infection or I7 protease expression. Reduction of miR122 would result in the suppression of HCV sub-genomic RNA replication, and, in turn, the amount of viral proteins. As expected, significant reduction of HCVNS5A protein was detected after VV infection and I7 protease expression. Therefore, our results suggest that VV could cleave Dicer protein through I7 protease to facilitate Dicer degradation, and in turn, suppress the processing of miRNAs. Effect of Dicer protein on VV replication was also studied. Exogenous expression of Dicer protein suppresses VV replication slightly while knockdown of Dicer protein does not affect VV replication significantly.
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Affiliation(s)
- Jhih-Si Chen
- Department of Laboratory Medicine and Medical Biotechnology, Tzu Chi University, Hualien, Taiwan
| | - Hui-Chun Li
- Department of Biochemistry, Tzu Chi University, Hualien, Taiwan
| | - Shu-I Lin
- Department of Laboratory Medicine and Medical Biotechnology, Tzu Chi University, Hualien, Taiwan
| | - Chee-Hing Yang
- Department of Laboratory Medicine and Medical Biotechnology, Tzu Chi University, Hualien, Taiwan
| | - Wan-Yu Chien
- Department of Laboratory Medicine and Medical Biotechnology, Tzu Chi University, Hualien, Taiwan
| | - Ciao-Ling Syu
- Department of Laboratory Medicine and Medical Biotechnology, Tzu Chi University, Hualien, Taiwan
| | - Shih-Yen Lo
- Department of Laboratory Medicine and Medical Biotechnology, Tzu Chi University, Hualien, Taiwan
- Department of Laboratory Medicine, Buddhist Tzu Chi General Hospital, Hualien, Taiwan
- * E-mail:
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