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Lee SH, Jung S, Lee YJ, Hyun M, Chung KC. FBXO7 triggers caspase 8-mediated proteolysis of the transcription factor FOXO4 and exacerbates neuronal cytotoxicity. J Biol Chem 2021; 297:101426. [PMID: 34800438 PMCID: PMC8665361 DOI: 10.1016/j.jbc.2021.101426] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 11/05/2021] [Accepted: 11/15/2021] [Indexed: 01/26/2023] Open
Abstract
Parkinson's disease (PD) is characterized by the progressive loss of midbrain dopamine neurons in the substantia nigra. Mutations in the F-box only protein 7 gene (Fbxo7) have been reported to cause an autosomal recessive form of early-onset familial PD. FBXO7 is a part of the SKP1-Cullin1-F-box (SCF) E3 ubiquitin ligase complex, which mediates ubiquitination of numerous substrates. FBXO7 also regulates mitophagy, cell growth, and proteasome activity. A member of the FOXO family, the transcription factor FOXO4, is also known to modulate several cellular responses, including cell cycle progression and apoptosis; however, the relationship between FBXO7 and FOXO4 has not been investigated. In this study, we determined that FBXO7 binds to FOXO4 and negatively regulates intracellular FOXO4 levels. Interestingly, we also found that FBXO7-mediated degradation of FOXO4 did not occur through either of two major proteolysis systems, the ubiquitin-proteasome system or the lysosome-autophagy pathway, although it was blocked by a caspase 8-specific inhibitor and caspase 8-knockdown. Moreover, intracellular FOXO4 levels were greatly reduced in dopaminergic MN9D cells following treatment with neurotoxic 6-hydroxydopamine (6-OHDA), which was produced upon FBXO7-mediated and caspase 8-mediated proteolysis. Taken together, these results suggest that FOXO4 is negatively regulated in FBXO7-linked PD through caspase 8 activation, suppressing the cytoprotective effect of FOXO4 during 6-OHDA-induced neuronal cell death.
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Affiliation(s)
- Su Hyoun Lee
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Sungyeon Jung
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Yun Ju Lee
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Minju Hyun
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Kwang Chul Chung
- Department of Systems Biology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea.
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Wang W, Qin JJ, Rajaei M, Li X, Yu X, Hunt C, Zhang R. Targeting MDM2 for novel molecular therapy: Beyond oncology. Med Res Rev 2019; 40:856-880. [PMID: 31587329 DOI: 10.1002/med.21637] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 08/20/2019] [Accepted: 08/21/2019] [Indexed: 12/14/2022]
Abstract
The murine double minute 2 (MDM2) oncogene exerts major oncogenic activities in human cancers; it is not only the best-documented negative regulator of the p53 tumor suppressor, but also exerts p53-independent activities. There is an increasing interest in developing MDM2-based targeted therapies. Several classes of MDM2 inhibitors have been evaluated in preclinical models, with a few entering clinical trials, mainly for cancer therapy. However, noncarcinogenic roles for MDM2 have also been identified, demonstrating that MDM2 is involved in many chronic diseases and conditions such as inflammation and autoimmune diseases, dementia and neurodegenerative diseases, heart failure and cardiovascular diseases, nephropathy, diabetes, obesity, and sterility. MDM2 inhibitors have been shown to have promising therapeutic efficacy for treating inflammation and other nonmalignant diseases in preclinical evaluations. Therefore, targeting MDM2 may represent a promising approach for treating and preventing these nonmalignant diseases. In addition, a better understanding of how MDM2 works in nonmalignant diseases may provide new biomarkers for their diagnosis, prognostic prediction, and monitoring of therapeutic outcome. In this review article, we pay special attention to the recent findings related to the roles of MDM2 in the pathogenesis of several nonmalignant diseases, the therapeutic potential of its downregulation or inhibition, and its use as a biomarker.
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Affiliation(s)
- Wei Wang
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas.,Drug Discovery Institute, University of Houston, Houston, Texas
| | - Jiang-Jiang Qin
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas
| | - Mehrdad Rajaei
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas
| | - Xin Li
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas
| | - Xiaoyi Yu
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas
| | - Courtney Hunt
- Drug Discovery Institute, University of Houston, Houston, Texas
| | - Ruiwen Zhang
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas.,Drug Discovery Institute, University of Houston, Houston, Texas
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Zhang SG, Wang XS, Zhang YD, Di Q, Shi JP, Qian M, Xu LG, Lin XJ, Lu J. Indirubin-3'-monoxime suppresses amyloid-beta-induced apoptosis by inhibiting tau hyperphosphorylation. Neural Regen Res 2016; 11:988-93. [PMID: 27482230 PMCID: PMC4962599 DOI: 10.4103/1673-5374.184500] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Indirubin-3′-monoxime is an effective inhibitor of cyclin-dependent protein kinases, and may play an obligate role in neuronal apoptosis in Alzheimer's disease. Here, we found that indirubin-3′-monoxime improved the morphology and increased the survival rate of SH-SY5Y cells exposed to amyloid-beta 25–35 (Aβ25–35), and also suppressed apoptosis by reducing tau phosphorylation at Ser199 and Thr205. Furthermore, indirubin-3′-monoxime inhibited phosphorylation of glycogen synthase kinase-3β (GSK-3β). Our results suggest that indirubin-3′-monoxime reduced Aβ25–35-induced apoptosis by suppressing tau hyperphosphorylation via a GSK-3β-mediated mechanism. Indirubin-3′-monoxime is a promising drug candidate for Alzheimer's disease.
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Affiliation(s)
- Shu-Gang Zhang
- Department of Neurology, Affiliated Nanjing Brain Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Xiao-Shan Wang
- Department of Neurology, Affiliated Nanjing Brain Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Ying-Dong Zhang
- Department of Neurology, Affiliated Nanjing Brain Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, China; Department of Neurology, Affiliated Nanjing First Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Qing Di
- Department of Neurology, Affiliated Nanjing Brain Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Jing-Ping Shi
- Department of Neurology, Affiliated Nanjing Brain Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Min Qian
- Department of Neurology, Affiliated Nanjing Brain Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Li-Gang Xu
- Department of Neurology, Affiliated Nanjing Brain Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Xing-Jian Lin
- Department of Neurology, Affiliated Nanjing Brain Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Jie Lu
- Department of Neurology, Affiliated Nanjing Brain Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, China
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