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Jiao D, Sun H, Zhao X, Chen Y, Lv Z, Shi Q, Li Y, Wang C, Gao K. mTORC1/S6K1 signaling promotes sustained oncogenic translation through modulating CRL3 IBTK-mediated ubiquitination of eIF4A1 in cancer cells. eLife 2024; 12:RP92236. [PMID: 38738857 PMCID: PMC11090508 DOI: 10.7554/elife.92236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2024] Open
Abstract
Enhanced protein synthesis is a crucial molecular mechanism that allows cancer cells to survive, proliferate, metastasize, and develop resistance to anti-cancer treatments, and often arises as a consequence of increased signaling flux channeled to mRNA-bearing eukaryotic initiation factor 4F (eIF4F). However, the post-translational regulation of eIF4A1, an ATP-dependent RNA helicase and subunit of the eIF4F complex, is still poorly understood. Here, we demonstrate that IBTK, a substrate-binding adaptor of the Cullin 3-RING ubiquitin ligase (CRL3) complex, interacts with eIF4A1. The non-degradative ubiquitination of eIF4A1 catalyzed by the CRL3IBTK complex promotes cap-dependent translational initiation, nascent protein synthesis, oncogene expression, and cervical tumor cell growth both in vivo and in vitro. Moreover, we show that mTORC1 and S6K1, two key regulators of protein synthesis, directly phosphorylate IBTK to augment eIF4A1 ubiquitination and sustained oncogenic translation. This link between the CRL3IBTK complex and the mTORC1/S6K1 signaling pathway, which is frequently dysregulated in cancer, represents a promising target for anti-cancer therapies.
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Affiliation(s)
- Dongyue Jiao
- State Key Laboratory of Genetic Engineering, Shanghai Stomatological Hospital & School of Stomatology, MOE Engineering Research Center of Gene Technology, Shanghai Engineering Research Center of Industrial Microorganisms, School of Life Sciences, Fudan UniversityShanghaiChina
| | - Huiru Sun
- State Key Laboratory of Genetic Engineering, Shanghai Stomatological Hospital & School of Stomatology, MOE Engineering Research Center of Gene Technology, Shanghai Engineering Research Center of Industrial Microorganisms, School of Life Sciences, Fudan UniversityShanghaiChina
| | - Xiaying Zhao
- State Key Laboratory of Genetic Engineering, Shanghai Stomatological Hospital & School of Stomatology, MOE Engineering Research Center of Gene Technology, Shanghai Engineering Research Center of Industrial Microorganisms, School of Life Sciences, Fudan UniversityShanghaiChina
| | - Yingji Chen
- State Key Laboratory of Genetic Engineering, Shanghai Stomatological Hospital & School of Stomatology, MOE Engineering Research Center of Gene Technology, Shanghai Engineering Research Center of Industrial Microorganisms, School of Life Sciences, Fudan UniversityShanghaiChina
| | - Zeheng Lv
- Department of Clinical Laboratory, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji UniversityShanghaiChina
- Shanghai Key Laboratory of Maternal Fetal Medicine, Shanghai Institute of Maternal-Fetal Medicine and Gynecologic Oncology, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji UniversityShanghaiChina
| | - Qing Shi
- State Key Laboratory of Genetic Engineering, Shanghai Stomatological Hospital & School of Stomatology, MOE Engineering Research Center of Gene Technology, Shanghai Engineering Research Center of Industrial Microorganisms, School of Life Sciences, Fudan UniversityShanghaiChina
| | - Yao Li
- State Key Laboratory of Genetic Engineering, Shanghai Stomatological Hospital & School of Stomatology, MOE Engineering Research Center of Gene Technology, Shanghai Engineering Research Center of Industrial Microorganisms, School of Life Sciences, Fudan UniversityShanghaiChina
| | - Chenji Wang
- State Key Laboratory of Genetic Engineering, Shanghai Stomatological Hospital & School of Stomatology, MOE Engineering Research Center of Gene Technology, Shanghai Engineering Research Center of Industrial Microorganisms, School of Life Sciences, Fudan UniversityShanghaiChina
| | - Kun Gao
- Department of Clinical Laboratory, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji UniversityShanghaiChina
- Shanghai Key Laboratory of Maternal Fetal Medicine, Shanghai Institute of Maternal-Fetal Medicine and Gynecologic Oncology, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji UniversityShanghaiChina
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Skurat AV, Segvich DM, Contreras CJ, Hu YC, Hurley TD, DePaoli-Roach AA, Roach PJ. Impaired malin expression and interaction with partner proteins in Lafora disease. J Biol Chem 2024; 300:107271. [PMID: 38588813 PMCID: PMC11063907 DOI: 10.1016/j.jbc.2024.107271] [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: 02/17/2024] [Revised: 03/25/2024] [Accepted: 03/27/2024] [Indexed: 04/10/2024] Open
Abstract
Lafora disease (LD) is an autosomal recessive myoclonus epilepsy with onset in the teenage years leading to death within a decade of onset. LD is characterized by the overaccumulation of hyperphosphorylated, poorly branched, insoluble, glycogen-like polymers called Lafora bodies. The disease is caused by mutations in either EPM2A, encoding laforin, a dual specificity phosphatase that dephosphorylates glycogen, or EMP2B, encoding malin, an E3-ubiquitin ligase. While glycogen is a widely accepted laforin substrate, substrates for malin have been difficult to identify partly due to the lack of malin antibodies able to detect malin in vivo. Here we describe a mouse model in which the malin gene is modified at the C-terminus to contain the c-myc tag sequence, making an expression of malin-myc readily detectable. Mass spectrometry analyses of immunoprecipitates using c-myc tag antibodies demonstrate that malin interacts with laforin and several glycogen-metabolizing enzymes. To investigate the role of laforin in these interactions we analyzed two additional mouse models: malin-myc/laforin knockout and malin-myc/LaforinCS, where laforin was either absent or the catalytic Cys was genomically mutated to Ser, respectively. The interaction of malin with partner proteins requires laforin but is not dependent on its catalytic activity or the presence of glycogen. Overall, the results demonstrate that laforin and malin form a complex in vivo, which stabilizes malin and enhances interaction with partner proteins to facilitate normal glycogen metabolism. They also provide insights into the development of LD and the rescue of the disease by the catalytically inactive phosphatase.
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Affiliation(s)
- Alexander V Skurat
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA; Lafora Epilepsy Cure Initiative, University of Kentucky College of Medicine, Lexington, Kentucky, USA
| | - Dyann M Segvich
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA; Lafora Epilepsy Cure Initiative, University of Kentucky College of Medicine, Lexington, Kentucky, USA
| | - Christopher J Contreras
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA; Lafora Epilepsy Cure Initiative, University of Kentucky College of Medicine, Lexington, Kentucky, USA
| | - Yueh-Chiang Hu
- Division of Developmental Biology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Thomas D Hurley
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA; Lafora Epilepsy Cure Initiative, University of Kentucky College of Medicine, Lexington, Kentucky, USA.
| | - Anna A DePaoli-Roach
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA; Lafora Epilepsy Cure Initiative, University of Kentucky College of Medicine, Lexington, Kentucky, USA.
| | - Peter J Roach
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA; Lafora Epilepsy Cure Initiative, University of Kentucky College of Medicine, Lexington, Kentucky, USA
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Song X, Sun J, Liu H, Mushtaq A, Huang Z, Li D, Zhang L, Chen F. Lycopene Alleviates Endoplasmic Reticulum Stress in Steatohepatitis through Inhibition of the ASK1-JNK Signaling Pathway. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:7832-7844. [PMID: 38544357 DOI: 10.1021/acs.jafc.3c08108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Abstract
Lycopene has been proven to alleviate nonalcoholic steatohepatitis (NASH), but the precise mechanisms are inadequately elucidated. In this study, we found a previously unknown regulatory effect of lycopene on the apoptosis signal-regulating kinase 1 (ASK1) signaling pathway in both in vivo and in vitro models. Lycopene supplementation (3 and 6 mg/kg/day) exhibited a significant reduction in lipid accumulation, inflammation, and fibrosis of the liver in mice fed with a high-fat/high-cholesterol diet or a methionine-choline-deficient diet. RNA sequencing uncovered that the mitogen-activated protein kinases signaling pathway, which is closely associated with inflammation and endoplasmic reticulum (ER) stress, was significantly downregulated by lycopene. Furthermore, we found lycopene ameliorated ER swelling and decreased the expression levels of ER stress markers (i.e., immunoglobulin heavy chain binding protein, C/EBP homologous protein, and X-box binding protein 1s). Especially, the inositol-requiring enzyme 1α involved in the ASK1 phosphorylation was inhibited by lycopene, resulting in the decline of the subsequent c-Jun N-terminal kinase (JNK) signaling cascade. ASK1 inhibitor DQOP-1 eliminated the lycopene-induced inhibition of the ASK1-JNK pathway in oleic acid and palmitic acid-induced HepG2 cells. Molecular docking further indicated hydrophobic interactions between lycopene and ASK1. Collectively, our research indicates that lycopene can alleviate ER stress and attenuate inflammation cascades and lipid accumulation by inhibiting the ASK1-JNK pathway.
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Affiliation(s)
- Xunyu Song
- College of Food Science and Nutritional Engineering, National Engineering Research Centre for Fruit and Vegetable Processing, Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture; Engineering Research Centre for Fruits and Vegetables Processing, Ministry of Education, China Agricultural University, Beijing 100083, China
| | - Jun Sun
- College of Food Science and Nutritional Engineering, National Engineering Research Centre for Fruit and Vegetable Processing, Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture; Engineering Research Centre for Fruits and Vegetables Processing, Ministry of Education, China Agricultural University, Beijing 100083, China
| | - Hanxiong Liu
- School of Food Science and Technology, National Engineering Research Center of Seafood, Dalian Polytechnic University, Dalian 116034, China
| | - Aroosa Mushtaq
- College of Food Science and Nutritional Engineering, National Engineering Research Centre for Fruit and Vegetable Processing, Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture; Engineering Research Centre for Fruits and Vegetables Processing, Ministry of Education, China Agricultural University, Beijing 100083, China
| | - Zhoumei Huang
- College of Food Science and Nutritional Engineering, National Engineering Research Centre for Fruit and Vegetable Processing, Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture; Engineering Research Centre for Fruits and Vegetables Processing, Ministry of Education, China Agricultural University, Beijing 100083, China
| | - Daotong Li
- College of Food Science and Nutritional Engineering, National Engineering Research Centre for Fruit and Vegetable Processing, Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture; Engineering Research Centre for Fruits and Vegetables Processing, Ministry of Education, China Agricultural University, Beijing 100083, China
| | - Lujia Zhang
- College of Food Science and Nutritional Engineering, National Engineering Research Centre for Fruit and Vegetable Processing, Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture; Engineering Research Centre for Fruits and Vegetables Processing, Ministry of Education, China Agricultural University, Beijing 100083, China
| | - Fang Chen
- College of Food Science and Nutritional Engineering, National Engineering Research Centre for Fruit and Vegetable Processing, Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture; Engineering Research Centre for Fruits and Vegetables Processing, Ministry of Education, China Agricultural University, Beijing 100083, China
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Wek RC, Anthony TG, Staschke KA. Surviving and Adapting to Stress: Translational Control and the Integrated Stress Response. Antioxid Redox Signal 2023; 39:351-373. [PMID: 36943285 PMCID: PMC10443206 DOI: 10.1089/ars.2022.0123] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 02/16/2023] [Accepted: 02/20/2023] [Indexed: 03/23/2023]
Abstract
Significance: Organisms adapt to changing environments by engaging cellular stress response pathways that serve to restore proteostasis and enhance survival. A primary adaptive mechanism is the integrated stress response (ISR), which features phosphorylation of the α subunit of eukaryotic translation initiation factor 2 (eIF2). Four eIF2α kinases respond to different stresses, enabling cells to rapidly control translation to optimize management of resources and reprogram gene expression for stress adaptation. Phosphorylation of eIF2 blocks its guanine nucleotide exchange factor, eIF2B, thus lowering the levels of eIF2 bound to GTP that is required to deliver initiator transfer RNA (tRNA) to ribosomes. While bulk messenger RNA (mRNA) translation can be sharply lowered by heightened phosphorylation of eIF2α, there are other gene transcripts whose translation is unchanged or preferentially translated. Among the preferentially translated genes is ATF4, which directs transcription of adaptive genes in the ISR. Recent Advances and Critical Issues: This review focuses on how eIF2α kinases function as first responders of stress, the mechanisms by which eIF2α phosphorylation and other stress signals regulate the exchange activity of eIF2B, and the processes by which the ISR triggers differential mRNA translation. To illustrate the synergy between stress pathways, we describe the mechanisms and functional significance of communication between the ISR and another key regulator of translation, mammalian/mechanistic target of rapamycin complex 1 (mTORC1), during acute and chronic amino acid insufficiency. Finally, we discuss the pathological conditions that stem from aberrant regulation of the ISR, as well as therapeutic strategies targeting the ISR to alleviate disease. Future Directions: Important topics for future ISR research are strategies for modulating this stress pathway in disease conditions and drug development, molecular processes for differential translation and the coordinate regulation of GCN2 and other stress pathways during physiological and pathological conditions. Antioxid. Redox Signal. 39, 351-373.
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Affiliation(s)
- Ronald C. Wek
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Indiana University Melvin and Bren Simon Comprehensive Cancer Center, Indianapolis, Indiana, USA
| | - Tracy G. Anthony
- Department of Nutritional Sciences, Rutgers University, New Brunswick, New Jersey, USA
| | - Kirk A. Staschke
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Indiana University Melvin and Bren Simon Comprehensive Cancer Center, Indianapolis, Indiana, USA
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Amin PH, Carlson KR, Wek RC. An RNA stem-loop functions in conjunction with an upstream open reading frame to direct preferential translation in the integrated stress response. J Biol Chem 2023; 299:102864. [PMID: 36596357 PMCID: PMC9971878 DOI: 10.1016/j.jbc.2022.102864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 11/30/2022] [Accepted: 12/28/2022] [Indexed: 01/02/2023] Open
Abstract
In response to environmental stresses, cells invoke translational control to conserve resources and rapidly reprogram gene expression for optimal adaptation. A central mechanism for translational control involves phosphorylation of the α subunit of eIF2 (p-eIF2α), which reduces delivery of initiator tRNA to ribosomes. Because p-eIF2α is invoked by multiple protein kinases, each responding to distinct stresses, this pathway is named the integrated stress response (ISR). While p-eIF2α lowers bulk translation initiation, many stress-related mRNAs are preferentially translated. The process by which ribosomes delineate gene transcripts for preferential translation is known to involve upstream open reading frames (uORFs) embedded in the targeted mRNAs. In this study, we used polysome analyses and reporter assays to address the mechanisms directing preferential translation of human IBTKα in the ISR. The IBTKα mRNA encodes four uORFs, with only 5'-proximal uORF1 and uORF2 being translated. Of importance, the 5'-leader of IBTKα mRNA also contains a phylogenetically conserved stem-loop of moderate stability that is situated 11 nucleotides downstream of uORF2. The uORF2 is well translated and functions in combination with the stem-loop to effectively lower translation reinitiation at the IBTKα coding sequence. Upon stress-induced p-eIF2α, the uORF2/stem loop element can be bypassed to enhance IBTKα translation by a mechanism that may involve the modestly translated uORF1. Our study demonstrates that uORFs in conjunction with RNA secondary structures can be critical elements that serve as the "bar code" by which scanning ribosomes can delineate which mRNAs are preferentially translated in the ISR.
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Affiliation(s)
- Parth H Amin
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Kenneth R Carlson
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Ronald C Wek
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA.
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Ren J, Wang X, Yee C, Gorrell MD, McLennan SV, Twigg SM. Sitagliptin Is More Effective Than Gliclazide in Preventing Pro-Fibrotic and Pro-Inflammatory Changes in a Rodent Model of Diet-Induced Non-Alcoholic Fatty Liver Disease. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27030727. [PMID: 35163991 PMCID: PMC8838637 DOI: 10.3390/molecules27030727] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 01/14/2022] [Accepted: 01/18/2022] [Indexed: 02/06/2023]
Abstract
A diet-induced non-alcoholic fatty liver disease (NAFLD) model causing obesity in rodents was used to examine whether sitagliptin and gliclazide therapies have similar protective effects on pathological liver change. Methods: Male mice were fed a high-fat diet (HFD) or standard chow (Chow) ad libitum for 25 weeks and randomly allocated to oral sitagliptin or gliclazide treatment for the final 10 weeks. Fasting blood glucose and circulating insulin were measured. Inflammatory and fibrotic liver markers were assessed by qPCR. The second messenger ERK and autophagy markers were examined by Western immunoblot. F4/80, collagens and CCN2 were assessed by immunohistochemistry (IHC). Results: At termination, HFD mice were obese, hyperinsulinemic and insulin-resistant but non-diabetic. The DPP4 inhibitor sitagliptin prevented intrahepatic induction of pro-fibrotic markers collagen-IV, collagen-VI, CCN2 and TGF-β1 and pro-inflammatory markers TNF-α and IL-1β more effectively than sulfonylurea gliclazide. By IHC, liver collagen-VI and CCN2 induction by HFD were inhibited only by sitagliptin. Sitagliptin had a greater ability than gliclazide to normalise ERK-protein liver dysregulation. Conclusion: These data indicate that sitagliptin, compared with gliclazide, exhibits greater inhibition of pro-fibrotic and pro-inflammatory changes in an HFD-induced NAFLD model. Sitagliptin therapy, even in the absence of diabetes, may have specific benefits in diet-induced NAFLD.
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Affiliation(s)
- Jing Ren
- Greg Brown Diabetes and Endocrinology Research Laboratories, Sydney Medical School (Central), Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW 2006, Australia; (J.R.); (X.W.); (C.Y.); (S.V.M.)
| | - Xiaoyu Wang
- Greg Brown Diabetes and Endocrinology Research Laboratories, Sydney Medical School (Central), Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW 2006, Australia; (J.R.); (X.W.); (C.Y.); (S.V.M.)
| | - Christine Yee
- Greg Brown Diabetes and Endocrinology Research Laboratories, Sydney Medical School (Central), Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW 2006, Australia; (J.R.); (X.W.); (C.Y.); (S.V.M.)
| | - Mark D. Gorrell
- Liver Enzymes in Metabolism and Inflammation Program, Centenary Institute, The University of Sydney, Newtown, NSW 2042, Australia;
- A.W. Morrow Gastroenterology and Liver Centre, Royal Prince Alfred Hospital, Camperdown, NSW 2050, Australia
| | - Susan V. McLennan
- Greg Brown Diabetes and Endocrinology Research Laboratories, Sydney Medical School (Central), Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW 2006, Australia; (J.R.); (X.W.); (C.Y.); (S.V.M.)
- Department of Endocrinology, Royal Prince Alfred Hospital, Camperdown, NSW 2050, Australia
- New South Wales Health Pathology (Eastern), Camperdown, NSW 2050, Australia
| | - Stephen M. Twigg
- Greg Brown Diabetes and Endocrinology Research Laboratories, Sydney Medical School (Central), Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW 2006, Australia; (J.R.); (X.W.); (C.Y.); (S.V.M.)
- Department of Endocrinology, Royal Prince Alfred Hospital, Camperdown, NSW 2050, Australia
- Correspondence: ; Tel.: +612-8627-1890; Fax: +612-8627-1604
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7
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Niture S, Lin M, Rios-Colon L, Qi Q, Moore JT, Kumar D. Emerging Roles of Impaired Autophagy in Fatty Liver Disease and Hepatocellular Carcinoma. Int J Hepatol 2021; 2021:6675762. [PMID: 33976943 PMCID: PMC8083829 DOI: 10.1155/2021/6675762] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 03/16/2021] [Accepted: 04/06/2021] [Indexed: 02/07/2023] Open
Abstract
Autophagy is a conserved catabolic process that eliminates dysfunctional cytosolic biomolecules through vacuole-mediated sequestration and lysosomal degradation. Although the molecular mechanisms that regulate autophagy are not fully understood, recent work indicates that dysfunctional/impaired autophagic functions are associated with the development and progression of nonalcoholic fatty liver disease (NAFLD), alcoholic fatty liver disease (AFLD), and hepatocellular carcinoma (HCC). Autophagy prevents NAFLD and AFLD progression through enhanced lipid catabolism and decreasing hepatic steatosis, which is characterized by the accumulation of triglycerides and increased inflammation. However, as both diseases progress, autophagy can become impaired leading to exacerbation of both pathological conditions and progression into HCC. Due to the significance of impaired autophagy in these diseases, there is increased interest in studying pathways and targets involved in maintaining efficient autophagic functions as potential therapeutic targets. In this review, we summarize how impaired autophagy affects liver function and contributes to NAFLD, AFLD, and HCC progression. We will also explore how recent discoveries could provide novel therapeutic opportunities to effectively treat these diseases.
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Affiliation(s)
- Suryakant Niture
- Julius L. Chambers Biomedical Biotechnology Research Institute, North Carolina Central University Durham, NC 27707, USA
| | - Minghui Lin
- The Fourth People's Hospital of Ningxia Hui Autonomous Region, Yinchuan, China 750021
| | - Leslimar Rios-Colon
- Julius L. Chambers Biomedical Biotechnology Research Institute, North Carolina Central University Durham, NC 27707, USA
| | - Qi Qi
- Julius L. Chambers Biomedical Biotechnology Research Institute, North Carolina Central University Durham, NC 27707, USA
| | - John T. Moore
- Julius L. Chambers Biomedical Biotechnology Research Institute, North Carolina Central University Durham, NC 27707, USA
| | - Deepak Kumar
- Julius L. Chambers Biomedical Biotechnology Research Institute, North Carolina Central University Durham, NC 27707, USA
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Li L, Xie P, Lin W, Liu J, Chen J, Guo Z, Bin C, An W, Zhang C, Zhan Y. CKIP-1 augments autophagy in steatotic hepatocytes by inhibiting Akt/mTOR signal pathway. Exp Cell Res 2020; 397:112341. [PMID: 33191205 DOI: 10.1016/j.yexcr.2020.112341] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 09/26/2020] [Accepted: 10/21/2020] [Indexed: 12/23/2022]
Abstract
Nonalcoholic fatty liver disease (NAFLD), which is characterized by aberrant accumulation of intrahepatic triglycerides and lipid droplets (LDs) in the liver cells, is becoming increasingly prevalent at an alarming rate worldwide. LDs can be consumed by either hydrolysis or autophagy, which is shown to be of importance in the regulation of hepatic lipid metabolism. We have shown that deficiency of pleckstrin homology domain-containing casein kinase 2 interacting protein-1 (CKIP-1), a scaffold protein that interacts with various proteins in multiple signal pathways, in mice aggravates high-fat diet induced fatty liver. However, its underlying mechanisms remain largely unknown. In this study, we found that the mRNA and protein levels of CKIP-1 decreased dramatically in steatotic HepG2 cells induced by oleic acid (OA) treatment. Coincidently, hepatic autophagy was also dynamically regulated in steatotic HepG2 cells. In addition, overexpression of CKIP-1 activated autophagy by suppression of Akt/mTOR signaling, which in turn reduced lipid accumulation. Moreover, these phenomena were reversed in CKIP-1-shRNA transfected steatotic hepatocytes. To further evaluate the potential role of CKIP-1 in autophagy, we determined the level of autophagy related proteins in CKIP-1 knockout mice. These results supported our findings in vitro. In summary, we found CKIP-1 to be a positive regulator of hepatic autophagy and a promising therapeutic target for treatment of NAFLD.
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Affiliation(s)
- Li Li
- Department of Gastroenterology, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China
| | - Ping Xie
- Department of Cell Biology, Municipal Laboratory for Liver Protection and Regulation of Regeneration, Capital Medical University, Beijing, 100069, China
| | - Wenjun Lin
- Department of Gastroenterology, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China
| | - Jinsheng Liu
- Department of Anesthesiology, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China
| | - Jing Chen
- Department of Gastroenterology, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China
| | - Zihao Guo
- Department of Gastroenterology, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China
| | - Chuxuan Bin
- Department of Gastroenterology, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China
| | - Wei An
- Department of Cell Biology, Municipal Laboratory for Liver Protection and Regulation of Regeneration, Capital Medical University, Beijing, 100069, China.
| | - Chuan Zhang
- Department of Gastroenterology, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China.
| | - Yutao Zhan
- Department of Gastroenterology, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China.
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9
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Cousin MA, Conboy E, Wang JS, Lenz D, Schwab TL, Williams M, Abraham RS, Barnett S, El-Youssef M, Graham RP, Gutierrez Sanchez LH, Hasadsri L, Hoffmann GF, Hull NC, Kopajtich R, Kovacs-Nagy R, Li JQ, Marx-Berger D, McLin V, McNiven MA, Mounajjed T, Prokisch H, Rymen D, Schulze RJ, Staufner C, Yang Y, Clark KJ, Lanpher BC, Klee EW. RINT1 Bi-allelic Variations Cause Infantile-Onset Recurrent Acute Liver Failure and Skeletal Abnormalities. Am J Hum Genet 2019; 105:108-121. [PMID: 31204009 DOI: 10.1016/j.ajhg.2019.05.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 05/13/2019] [Indexed: 01/12/2023] Open
Abstract
Pediatric acute liver failure (ALF) is life threatening with genetic, immunologic, and environmental etiologies. Approximately half of all cases remain unexplained. Recurrent ALF (RALF) in infants describes repeated episodes of severe liver injury with recovery of hepatic function between crises. We describe bi-allelic RINT1 alterations as the cause of a multisystem disorder including RALF and skeletal abnormalities. Three unrelated individuals with RALF onset ≤3 years of age have splice alterations at the same position (c.1333+1G>A or G>T) in trans with a missense (p.Ala368Thr or p.Leu370Pro) or in-frame deletion (p.Val618_Lys619del) in RINT1. ALF episodes are concomitant with fever/infection and not all individuals have complete normalization of liver function testing between episodes. Liver biopsies revealed nonspecific liver damage including fibrosis, steatosis, or mild increases in Kupffer cells. Skeletal imaging revealed abnormalities affecting the vertebrae and pelvis. Dermal fibroblasts showed splice-variant mediated skipping of exon 9 leading to an out-of-frame product and nonsense-mediated transcript decay. Fibroblasts also revealed decreased RINT1 protein, abnormal Golgi morphology, and impaired autophagic flux compared to control. RINT1 interacts with NBAS, recently implicated in RALF, and UVRAG, to facilitate Golgi-to-ER retrograde vesicle transport. During nutrient depletion or infection, Golgi-to-ER transport is suppressed and autophagy is promoted through UVRAG regulation by mTOR. Aberrant autophagy has been associated with the development of similar skeletal abnormalities and also with liver disease, suggesting that disruption of these RINT1 functions may explain the liver and skeletal findings. Clarifying the pathomechanism underlying this gene-disease relationship may inform therapeutic opportunities.
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10
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Lebeaupin C, Vallée D, Hazari Y, Hetz C, Chevet E, Bailly-Maitre B. Endoplasmic reticulum stress signalling and the pathogenesis of non-alcoholic fatty liver disease. J Hepatol 2018; 69:927-947. [PMID: 29940269 DOI: 10.1016/j.jhep.2018.06.008] [Citation(s) in RCA: 528] [Impact Index Per Article: 88.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 05/22/2018] [Accepted: 06/14/2018] [Indexed: 12/13/2022]
Abstract
The global epidemic of obesity has been accompanied by a rising burden of non-alcoholic fatty liver disease (NAFLD), with manifestations ranging from simple steatosis to non-alcoholic steatohepatitis, potentially developing into hepatocellular carcinoma. Although much attention has focused on NAFLD, its pathogenesis remains largely obscure. The hallmark of NAFLD is the hepatic accumulation of lipids, which subsequently leads to cellular stress and hepatic injury, eventually resulting in chronic liver disease. Abnormal lipid accumulation often coincides with insulin resistance in steatotic livers and is associated with perturbed endoplasmic reticulum (ER) proteostasis in hepatocytes. In response to chronic ER stress, an adaptive signalling pathway known as the unfolded protein response is triggered to restore ER proteostasis. However, the unfolded protein response can cause inflammation, inflammasome activation and, in the case of non-resolvable ER stress, the death of hepatocytes. Experimental data suggest that the unfolded protein response influences hepatic tumour development, aggressiveness and response to treatment, offering novel therapeutic avenues. Herein, we provide an overview of the evidence linking ER stress to NAFLD and discuss possible points of intervention.
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Affiliation(s)
| | - Deborah Vallée
- Université Côte d'Azur, INSERM, U1065, C3M, 06200 Nice, France
| | - Younis Hazari
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, University of Chile, Santiago, Chile; Center for Geroscience, Brain Health and Metabolism (GERO), Santiago, Chile; Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile, Santiago, Chile
| | - Claudio Hetz
- Biomedical Neuroscience Institute (BNI), Faculty of Medicine, University of Chile, Santiago, Chile; Center for Geroscience, Brain Health and Metabolism (GERO), Santiago, Chile; Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile, Santiago, Chile; Buck Institute for Research on Aging, Novato, CA 94945, USA; Department of Immunology and Infectious Diseases, Harvard School of Public Health, 02115 Boston, MA, USA
| | - Eric Chevet
- "Chemistry, Oncogenesis, Stress, Signaling", Inserm U1242, Université de Rennes, Rennes, France; Centre de Lutte Contre le Cancer Eugène Marquis, Rennes, France
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11
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Khambu B, Yan S, Huda N, Liu G, Yin XM. Autophagy in non-alcoholic fatty liver disease and alcoholic liver disease. LIVER RESEARCH 2018; 2:112-119. [PMID: 31123622 PMCID: PMC6528826 DOI: 10.1016/j.livres.2018.09.004] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Autophagy is an evolutionarily conserved intracellular degradative function that is important for liver homeostasis. Accumulating evidence suggests that autophagy is deregulated during the progression and development of alcoholic and non-alcoholic liver diseases. Impaired autophagy prevents the clearance of excessive lipid droplets (LDs), damaged mitochondria, and toxic protein aggregates, which can be generated during the progression of various liver diseases, thus contributing to the development of steatosis, injury, steatohepatitis, fibrosis, and tumors. In this review, we look at the status of hepatic autophagy during the pathogenesis of alcoholic and non-alcoholic liver diseases. We also examine the mechanisms of defects in autophagy, and the hepato-protective roles of autophagy in non-alcoholic fatty liver disease (NAFLD) and alcoholic liver disease (ALD), focusing mainly on steatosis and liver injury. Finally, we discuss the therapeutic potential of autophagy modulating agents for the treatment of these two common liver diseases.
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12
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Akazawa Y, Nakao K. To die or not to die: death signaling in nonalcoholic fatty liver disease. J Gastroenterol 2018; 53:893-906. [PMID: 29574534 PMCID: PMC6061666 DOI: 10.1007/s00535-018-1451-5] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 03/09/2018] [Indexed: 02/07/2023]
Abstract
Non-alcoholic fatty liver disease (NAFLD) is an emerging liver disease worldwide. In subset of patients, NAFLD progresses to its advanced form, nonalcoholic steatohepatitis (NASH), which is accompanied with inflammation and fibrosis. Saturated free fatty acid-induced hepatocyte apoptosis is a feature of NASH. Death signaling in NASH does not always result in apoptosis, but can alternatively lead to the survival of cells presenting signs of pro-inflammatory and pro-fibrotic signals. With the current lack of established treatments for NASH, it is important to understand the molecular mechanisms responsible for disease development and progression. This review focuses on the latest findings in hepatocyte death signaling and discusses possible targets for intervention, including caspases, death receptor and c-Jun N-terminal kinase 1 signaling, oxidative stress, and endoplasmic reticulum stress, as well as epigenomic factors.
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Affiliation(s)
- Yuko Akazawa
- Department of Pathology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki City, 852-8501, Nagasaki, Japan.
- Department of Gastroenterology and Hepatology, Nagasaki University Hospital, Nagasaki City, 852-8501, Nagasaki, Japan.
| | - Kazuhiko Nakao
- Department of Gastroenterology and Hepatology, Nagasaki University Hospital, Nagasaki City, 852-8501, Nagasaki, Japan
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13
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Ryoo HD, Vasudevan D. Two distinct nodes of translational inhibition in the Integrated Stress Response. BMB Rep 2018; 50:539-545. [PMID: 28803610 PMCID: PMC5720466 DOI: 10.5483/bmbrep.2017.50.11.157] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2017] [Indexed: 12/21/2022] Open
Abstract
The Integrated Stress Response (ISR) refers to a signaling pathway initiated by stress-activated eIF2α kinases. Once activated, the pathway causes attenuation of global mRNA translation while also paradoxically inducing stress response gene expression. A detailed analysis of this pathway has helped us better understand how stressed cells coordinate gene expression at translational and transcriptional levels. The translational attenuation associated with this pathway has been largely attributed to the phosphorylation of the translational initiation factor eIF2α. However, independent studies are now pointing to a second translational regulation step involving a downstream ISR target, 4E-BP, in the inhibition of eIF4E and specifically cap-dependent translation. The activation of 4E-BP is consistent with previous reports implicating the roles of 4E-BP resistant, Internal Ribosome Entry Site (IRES) dependent translation in ISR active cells. In this review, we provide an overview of the translation inhibition mechanisms engaged by the ISR and how they impact the translation of stress response genes.
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Affiliation(s)
- Hyung Don Ryoo
- Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA
| | - Deepika Vasudevan
- Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA
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14
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Wek RC. Role of eIF2α Kinases in Translational Control and Adaptation to Cellular Stress. Cold Spring Harb Perspect Biol 2018; 10:a032870. [PMID: 29440070 PMCID: PMC6028073 DOI: 10.1101/cshperspect.a032870] [Citation(s) in RCA: 283] [Impact Index Per Article: 47.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A central mechanism regulating translation initiation in response to environmental stress involves phosphorylation of the α subunit of eukaryotic initiation factor 2 (eIF2α). Phosphorylation of eIF2α causes inhibition of global translation, which conserves energy and facilitates reprogramming of gene expression and signaling pathways that help to restore protein homeostasis. Coincident with repression of protein synthesis, many gene transcripts involved in the stress response are not affected or are even preferentially translated in response to increased eIF2α phosphorylation by mechanisms involving upstream open reading frames (uORFs). This review highlights the mechanisms regulating eIF2α kinases, the role that uORFs play in translational control, and the impact that alteration of eIF2α phosphorylation by gene mutations or small molecule inhibitors can have on health and disease.
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Affiliation(s)
- Ronald C Wek
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202-5126
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15
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Gstrein T, Edwards A, Přistoupilová A, Leca I, Breuss M, Pilat-Carotta S, Hansen AH, Tripathy R, Traunbauer AK, Hochstoeger T, Rosoklija G, Repic M, Landler L, Stránecký V, Dürnberger G, Keane TM, Zuber J, Adams DJ, Flint J, Honzik T, Gut M, Beltran S, Mechtler K, Sherr E, Kmoch S, Gut I, Keays DA. Mutations in Vps15 perturb neuronal migration in mice and are associated with neurodevelopmental disease in humans. Nat Neurosci 2018; 21:207-217. [PMID: 29311744 PMCID: PMC5897053 DOI: 10.1038/s41593-017-0053-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 11/22/2017] [Indexed: 01/31/2023]
Abstract
The formation of the vertebrate brain requires the generation, migration, differentiation and survival of neurons. Genetic mutations that perturb these critical cellular events can result in malformations of the telencephalon, providing a molecular window into brain development. Here we report the identification of an N-ethyl-N-nitrosourea-induced mouse mutant characterized by a fractured hippocampal pyramidal cell layer, attributable to defects in neuronal migration. We show that this is caused by a hypomorphic mutation in Vps15 that perturbs endosomal-lysosomal trafficking and autophagy, resulting in an upregulation of Nischarin, which inhibits Pak1 signaling. The complete ablation of Vps15 results in the accumulation of autophagic substrates, the induction of apoptosis and severe cortical atrophy. Finally, we report that mutations in VPS15 are associated with cortical atrophy and epilepsy in humans. These data highlight the importance of the Vps15-Vps34 complex and the Nischarin-Pak1 signaling hub in the development of the telencephalon.
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Affiliation(s)
- Thomas Gstrein
- Institute of Molecular Pathology (IMP), Vienna Biocentre (VBC), Vienna, Austria
| | - Andrew Edwards
- Wellcome Trust Center for Human Genetics (WTCHG), Oxford, UK
| | - Anna Přistoupilová
- Institute of Inherited Metabolic Disorders, Charles University, Prague, Czech Republic
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Ines Leca
- Institute of Molecular Pathology (IMP), Vienna Biocentre (VBC), Vienna, Austria
| | - Martin Breuss
- Institute of Molecular Pathology (IMP), Vienna Biocentre (VBC), Vienna, Austria
| | | | - Andi H Hansen
- Institute of Molecular Pathology (IMP), Vienna Biocentre (VBC), Vienna, Austria
| | - Ratna Tripathy
- Institute of Molecular Pathology (IMP), Vienna Biocentre (VBC), Vienna, Austria
| | - Anna K Traunbauer
- Institute of Molecular Pathology (IMP), Vienna Biocentre (VBC), Vienna, Austria
| | - Tobias Hochstoeger
- Institute of Molecular Pathology (IMP), Vienna Biocentre (VBC), Vienna, Austria
| | - Gavril Rosoklija
- Institute of Molecular Pathology (IMP), Vienna Biocentre (VBC), Vienna, Austria
| | - Marco Repic
- Institute for Molecular Biotechnology (IMBA), Vienna, Austria
| | - Lukas Landler
- Institute of Molecular Pathology (IMP), Vienna Biocentre (VBC), Vienna, Austria
| | - Viktor Stránecký
- Institute of Inherited Metabolic Disorders, Charles University, Prague, Czech Republic
| | - Gerhard Dürnberger
- Institute of Molecular Pathology (IMP), Vienna Biocentre (VBC), Vienna, Austria
| | - Thomas M Keane
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
| | - Johannes Zuber
- Institute of Molecular Pathology (IMP), Vienna Biocentre (VBC), Vienna, Austria
| | - David J Adams
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, UK
| | - Jonathan Flint
- Wellcome Trust Center for Human Genetics (WTCHG), Oxford, UK
| | - Tomas Honzik
- Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Marta Gut
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Sergi Beltran
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Karl Mechtler
- Institute of Molecular Pathology (IMP), Vienna Biocentre (VBC), Vienna, Austria
| | - Elliott Sherr
- Institute of Human Genetics, University of California, San Francisco, San Francisco, CA, USA
| | - Stanislav Kmoch
- Institute of Inherited Metabolic Disorders, Charles University, Prague, Czech Republic
| | - Ivo Gut
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - David A Keays
- Institute of Molecular Pathology (IMP), Vienna Biocentre (VBC), Vienna, Austria.
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