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Su Z, Lu W, Cao J, Xie Z, Zhao P. Endoplasmic reticulum stress in abdominal aortic aneurysm. INTERNATIONAL JOURNAL OF CARDIOLOGY. HEART & VASCULATURE 2024; 54:101500. [PMID: 39280692 PMCID: PMC11402186 DOI: 10.1016/j.ijcha.2024.101500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2024] [Revised: 08/20/2024] [Accepted: 08/22/2024] [Indexed: 09/18/2024]
Abstract
Abdominal aortic aneurysms (AAAs) are characterized by permanent dilatation of the abdominal aorta, which is accompanied by inflammation, degradation of the extracellular matrix (ECM) and disruption of vascular smooth muscle cell (VSMC) homeostasis. Endoplasmic reticulum (ER) stress is involved in the regulation of inflammation, oxidative stress and VSMC apoptosis, all of which are critical factors in AAA development. Although several studies have revealed the occurrence of ER stress in AAA development, the specific biological functions of ER stress in AAA development remain largely unknown. Given that targeting ER stress is a promising strategy for treating AAAs, further investigation of the physiological and pathological roles of ER stress in AAA development is warranted.
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Affiliation(s)
- Zhaohai Su
- Department of Cardiology, Affiliated Hospital of Yangzhou University, Yangzhou University, Jiangsu 225001, PR China
- Department of Cardiology, Ganzhou Hospital of Guangdong Provincial People's Hospital, Ganzhou Municipal Hospital (Gannan Medical University Affiliated Municipal Hospital), Ganzhou, Jiangxi 341000, PR China
| | - Weiling Lu
- Department of Cardiology, Ganzhou Hospital of Guangdong Provincial People's Hospital, Ganzhou Municipal Hospital (Gannan Medical University Affiliated Municipal Hospital), Ganzhou, Jiangxi 341000, PR China
| | - Jun Cao
- Department of Cardiology, Ganzhou Hospital of Guangdong Provincial People's Hospital, Ganzhou Municipal Hospital (Gannan Medical University Affiliated Municipal Hospital), Ganzhou, Jiangxi 341000, PR China
| | - Zheng Xie
- Department of General Practice, Ganzhou Hospital of Guangdong Provincial People's Hospital, Ganzhou Municipal Hospital (Gannan Medical University Affiliated Municipal Hospital), Ganzhou, Jiangxi 341000, PR China
| | - Pei Zhao
- Department of Cardiology, Affiliated Hospital of Yangzhou University, Yangzhou University, Jiangsu 225001, PR China
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2
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Kapuy O. Mechanism of Decision Making between Autophagy and Apoptosis Induction upon Endoplasmic Reticulum Stress. Int J Mol Sci 2024; 25:4368. [PMID: 38673953 PMCID: PMC11050573 DOI: 10.3390/ijms25084368] [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] [Received: 03/22/2024] [Revised: 04/10/2024] [Accepted: 04/15/2024] [Indexed: 04/28/2024] Open
Abstract
Dynamic regulation of the cellular proteome is mainly controlled in the endoplasmic reticulum (ER). Accumulation of misfolded proteins due to ER stress leads to the activation of unfolded protein response (UPR). The primary role of UPR is to reduce the bulk of damages and try to drive back the system to the former or a new homeostatic state by autophagy, while an excessive level of stress results in apoptosis. It has already been proven that the proper order and characteristic features of both surviving and self-killing mechanisms are controlled by negative and positive feedback loops, respectively. The new results suggest that these feedback loops are found not only within but also between branches of the UPR, fine-tuning the response to ER stress. In this review, we summarize the recent knowledge of the dynamical characteristic of endoplasmic reticulum stress response mechanism by using both theoretical and molecular biological techniques. In addition, this review pays special attention to describing the mechanism of action of the dynamical features of the feedback loops controlling cellular life-and-death decision upon ER stress. Since ER stress appears in diseases that are common worldwide, a more detailed understanding of the behaviour of the stress response is of medical importance.
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Affiliation(s)
- Orsolya Kapuy
- Department of Molecular Biology, Institute of Biochemistry and Molecular Biology, Semmelweis University, H-1085 Budapest, Hungary
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3
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Xu S, Liu H, Wang C, Deng Y, Xu B, Yang T, Liu W. Dual roles of UPR er and UPR mt in neurodegenerative diseases. J Mol Med (Berl) 2023; 101:1499-1512. [PMID: 37817014 DOI: 10.1007/s00109-023-02382-9] [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] [Received: 09/12/2022] [Revised: 09/22/2023] [Accepted: 09/26/2023] [Indexed: 10/12/2023]
Abstract
The unfolded protein response (UPR) is a cellular stress response mechanism induced by the accumulation of unfolded or misfolded proteins. Within the endoplasmic reticulum and mitochondria, a dynamic balance exists between protein folding mechanisms and unfolded protein levels under normal conditions. Disruption of this balance or an accumulation of unfolded proteins in these organelles can result in stress responses and UPR. The UPR restores organelle homeostasis and promotes cell survival by increasing the expression of chaperone proteins, regulating protein quality control systems, and enhancing the protein degradation pathway. However, prolonged or abnormal UPR can also have negative effects, including cell death. Therefore, many diseases, especially neurodegenerative diseases, are associated with UPR dysfunction. Neurodegenerative diseases are characterized by misfolded proteins accumulating and aggregating, and neuronal cells are particularly sensitive to misfolded proteins and are prone to degeneration. Many studies have shown that the UPR plays an important role in the pathogenesis of neurodegenerative diseases. Here, we will discuss the possible contributions of the endoplasmic reticulum unfolded protein response (UPRer) and the mitochondrial unfolded protein response (UPRmt) in the development of several neurodegenerative diseases.
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Affiliation(s)
- Si Xu
- Department of Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenbei New District, Shenyang 110122, Liaoning, China
| | - Haihui Liu
- Department of Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenbei New District, Shenyang 110122, Liaoning, China
| | - Chen Wang
- Department of Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenbei New District, Shenyang 110122, Liaoning, China
| | - Yu Deng
- Department of Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenbei New District, Shenyang 110122, Liaoning, China
| | - Bin Xu
- Department of Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenbei New District, Shenyang 110122, Liaoning, China
| | - Tianyao Yang
- Department of Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenbei New District, Shenyang 110122, Liaoning, China.
| | - Wei Liu
- Department of Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenbei New District, Shenyang 110122, Liaoning, China.
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4
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Chai L, Wang Q, Wang Y, Li D, Zhang Q, Chen Y, Liu J, Chen H, Qiu Y, Shen N, Wang J, Xie X, Li M. Downregulation of PDCD4 through STAT3/ATF6/autophagy mediates MIF-induced PASMCs proliferation/migration and vascular remodeling. Eur J Pharmacol 2023; 956:175968. [PMID: 37549728 DOI: 10.1016/j.ejphar.2023.175968] [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: 02/12/2023] [Revised: 07/08/2023] [Accepted: 08/04/2023] [Indexed: 08/09/2023]
Abstract
To address the molecular mechanisms underlying macrophage migration inhibitory factor (MIF) induced pulmonary artery smooth muscle cells (PASMCs) proliferation, migration and vascular remodeling in pulmonary hypertension (PH), primary cultured rat PASMCs and monocrotaline (MCT)-induced rats with PH were applied in the present study. The results showed that MIF increased signal transducer and activator of transcription 3 (STAT3) phosphorylation, and then stimulated activating transcription factor 6 (ATF6) activation, subsequently triggered autophagy activation, which further led to programmed cell death factor 4 (PDCD4) lysosomal degradation, and eventually promoted PASMCs proliferation/migration. In lung tissues of MCT rats, MIF protein expression was elevated, phosphorylation of STAT3 and activation of ATF6 were increased, activation of autophagy was evident, and reduction of PDCD4 was observed. Intervention with MIF inhibitor 4-Iodo-6-phenylpyrimidine (4-IPP), ATF6 blocker melatonin or autophagy inhibitor chloroquine, confirmed the in vitro interaction among MIF, STAT3, ATF6, autophagy and PDCD4 in MCT induced rats with PH. Targeting MIF/STAT3/ATF6/autophagy/PDCD4 axis effectively prevented the development of PH by suppressing PASMCs proliferation and vascular remodeling. In conclusions, we demonstrate that MIF activates the STAT3/ATF6/autophagy cascade and then degrades PDCD4 leading to PASMCs proliferation/migration and pulmonary vascular remodeling, suggesting that intervention this axis might have potential value in management of PH.
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Affiliation(s)
- Limin Chai
- Department of Respiratory Medicine, The First Affiliated Hospital of Xi'an JiaoTong, University, Xi'an, Shaanxi 710061, People's Republic of China
| | - Qingting Wang
- Department of Respiratory Medicine, The First Affiliated Hospital of Xi'an JiaoTong, University, Xi'an, Shaanxi 710061, People's Republic of China
| | - Yan Wang
- Department of Respiratory Medicine, The First Affiliated Hospital of Xi'an JiaoTong, University, Xi'an, Shaanxi 710061, People's Republic of China
| | - Danyang Li
- Department of Respiratory Medicine, The First Affiliated Hospital of Xi'an JiaoTong, University, Xi'an, Shaanxi 710061, People's Republic of China
| | - Qianqian Zhang
- Department of Respiratory Medicine, The First Affiliated Hospital of Xi'an JiaoTong, University, Xi'an, Shaanxi 710061, People's Republic of China
| | - Yuqian Chen
- Department of Respiratory Medicine, The First Affiliated Hospital of Xi'an JiaoTong, University, Xi'an, Shaanxi 710061, People's Republic of China
| | - Jin Liu
- Department of Respiratory Medicine, The First Affiliated Hospital of Xi'an JiaoTong, University, Xi'an, Shaanxi 710061, People's Republic of China
| | - Huan Chen
- Department of Respiratory Medicine, The First Affiliated Hospital of Xi'an JiaoTong, University, Xi'an, Shaanxi 710061, People's Republic of China
| | - Yuanjie Qiu
- Department of Respiratory Medicine, The First Affiliated Hospital of Xi'an JiaoTong, University, Xi'an, Shaanxi 710061, People's Republic of China
| | - Nirui Shen
- Department of Respiratory Medicine, The First Affiliated Hospital of Xi'an JiaoTong, University, Xi'an, Shaanxi 710061, People's Republic of China
| | - Jian Wang
- Department of Respiratory Medicine, The First Affiliated Hospital of Xi'an JiaoTong, University, Xi'an, Shaanxi 710061, People's Republic of China
| | - Xinming Xie
- Department of Respiratory Medicine, The First Affiliated Hospital of Xi'an JiaoTong, University, Xi'an, Shaanxi 710061, People's Republic of China
| | - Manxiang Li
- Department of Respiratory Medicine, The First Affiliated Hospital of Xi'an JiaoTong, University, Xi'an, Shaanxi 710061, People's Republic of China.
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Li X, Wang J, Li Y, He W, Cheng QJ, Liu X, Xu DL, Jiang ZG, Xiao X, He YH. The gp130/STAT3-endoplasmic reticulum stress axis regulates hepatocyte necroptosis in acute liver injury. Croat Med J 2023; 64:149-163. [PMID: 37391912 PMCID: PMC10332293 DOI: 10.3325/cmj.2023.64.149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 05/25/2023] [Indexed: 08/30/2023] Open
Abstract
AIM To investigate the effect of the gp130/STAT3-endoplasmic reticulum (ER) stress axis on hepatocyte necroptosis during acute liver injury. METHODS ER stress and liver injury in LO2 cells were induced with thapsigargin, and in BALB/c mice with tunicamycin and carbon tetrachloride (CCl4). Glycoprotein 130 (gp130) expression, the degrees of ER stress, and hepatocyte necroptosis were assessed. RESULTS ER stress significantly upregulated gp130 expression in LO2 cells and mouse livers. The silencing of activating transcription factor 6 (ATF6), but not of ATF4, increased hepatocyte necroptosis and mitigated gp130 expression in LO2 cells and mice. Gp130 silencing reduced the phosphorylation of CCl4-induced signal transducer and activator of transcription 3 (STAT3), and aggravated ER stress, necroptosis, and liver injury in mice. CONCLUSION ATF6/gp130/STAT3 signaling attenuates necroptosis in hepatocytes through the negative regulation of ER stress during liver injury. Hepatocyte ATF6/gp130/STAT3 signaling may be used as a therapeutic target in acute liver injury.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Yi-Huai He
- Yi-Huai He, Department of Infectious Diseases, Affiliated Hospital of Zunyi Medical University, No. 201 Dalian Street, Zunyi, 563000, Guizhou, China,
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6
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Li X, Wang J, Li Y, He W, Cheng QJ, Liu X, Xu DL, Jiang ZG, Xiao X, He YH. The gp130/STAT3-endoplasmic reticulum stress axis regulates hepatocyte necroptosis in acute liver injury. Croat Med J 2023; 64:149-163. [PMID: 37391912 PMCID: PMC10332293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 05/25/2023] [Indexed: 07/02/2023] Open
Abstract
AIM To investigate the effect of the gp130/STAT3-endoplasmic reticulum (ER) stress axis on hepatocyte necroptosis during acute liver injury. METHODS ER stress and liver injury in LO2 cells were induced with thapsigargin, and in BALB/c mice with tunicamycin and carbon tetrachloride (CCl4). Glycoprotein 130 (gp130) expression, the degrees of ER stress, and hepatocyte necroptosis were assessed. RESULTS ER stress significantly upregulated gp130 expression in LO2 cells and mouse livers. The silencing of activating transcription factor 6 (ATF6), but not of ATF4, increased hepatocyte necroptosis and mitigated gp130 expression in LO2 cells and mice. Gp130 silencing reduced the phosphorylation of CCl4-induced signal transducer and activator of transcription 3 (STAT3), and aggravated ER stress, necroptosis, and liver injury in mice. CONCLUSION ATF6/gp130/STAT3 signaling attenuates necroptosis in hepatocytes through the negative regulation of ER stress during liver injury. Hepatocyte ATF6/gp130/STAT3 signaling may be used as a therapeutic target in acute liver injury.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Yi-Huai He
- Yi-Huai He, Department of Infectious Diseases, Affiliated Hospital of Zunyi Medical University, No. 201 Dalian Street, Zunyi, 563000, Guizhou, China,
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Pagliara V, Amodio G, Vestuto V, Franceschelli S, Russo NA, Cirillo V, Mottola G, Remondelli P, Moltedo O. Myogenesis in C2C12 Cells Requires Phosphorylation of ATF6α by p38 MAPK. Biomedicines 2023; 11:biomedicines11051457. [PMID: 37239128 DOI: 10.3390/biomedicines11051457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 04/28/2023] [Accepted: 05/12/2023] [Indexed: 05/28/2023] Open
Abstract
Activating transcription factor 6α (ATF6α) is an endoplasmic reticulum protein known to participate in unfolded protein response (UPR) during ER stress in mammals. Herein, we show that in mouse C2C12 myoblasts induced to differentiate, ATF6α is the only pathway of the UPR activated. ATF6α stimulation is p38 MAPK-dependent, as revealed by the use of the inhibitor SB203580, which halts myotube formation and, at the same time, impairs trafficking of ATF6α, which accumulates at the cis-Golgi without being processed in the p50 transcriptional active form. To further evaluate the role of ATF6α, we knocked out the ATF6α gene, thus inhibiting the C2C12 myoblast from undergoing myogenesis, and this occurred independently from p38 MAPK activity. The expression of exogenous ATF6α in knocked-out ATF6α cells recover myogenesis, whereas the expression of an ATF6α mutant in the p38 MAPK phosphorylation site (T166) was not able to regain myogenesis. Genetic ablation of ATF6α also prevents the exit from the cell cycle, which is essential for muscle differentiation. Furthermore, when we inhibited differentiation by the use of dexamethasone in C2C12 cells, we found inactivation of p38 MAPK and, consequently, loss of ATF6α activity. All these findings suggest that the p-p38 MAPK/ATF6α axis, in pathophysiological conditions, regulates myogenesis by promoting the exit from the cell cycle, an essential step to start myoblasts differentiation.
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Affiliation(s)
- Valentina Pagliara
- Department of Medicine, Surgery and Dentistry "Scuola Medica Salernitana", University of Salerno, Via Salvador Allende, 84081 Baronissi, Italy
| | - Giuseppina Amodio
- Department of Medicine, Surgery and Dentistry "Scuola Medica Salernitana", University of Salerno, Via Salvador Allende, 84081 Baronissi, Italy
| | - Vincenzo Vestuto
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 84084 Fisciano, Italy
| | - Silvia Franceschelli
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 84084 Fisciano, Italy
| | - Nicola Antonino Russo
- Biogem, Istituto di Biologia e Genetica Molecolare, Via Camporeale, 83031 Ariano Irpino, Italy
| | - Vittorio Cirillo
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 84084 Fisciano, Italy
| | - Giovanna Mottola
- Centre de Recherche en Cardiovasculaire et Nutrition (C2VN) (AMU-INSERM 1263-INRAE 1260), Aix Marseille Université, Campus Timone, 27 Bd. Jean Moulin, 13005 Marseille, France
- Biogénopôle (BGP), Laboratoires de Biologie Médicale, Secteur Biochimie, Hôpital de La Timone, 264 Rue Saint-Pierre, 13005 Marseille, France
| | - Paolo Remondelli
- Department of Medicine, Surgery and Dentistry "Scuola Medica Salernitana", University of Salerno, Via Salvador Allende, 84081 Baronissi, Italy
| | - Ornella Moltedo
- Department of Pharmacy, University of Salerno, Via Giovanni Paolo II, 84084 Fisciano, Italy
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Harris TJ, Liao Y, Shi W, Evangelista M, Pal B, Puthalakath H, Aston R, Mollard R, Mariadason JM, Lee EF, Fairlie WD. Induction of endoplasmic reticulum stress is associated with the anti-tumor activity of monepantel across cancer types. Cancer Med 2023. [PMID: 37148543 DOI: 10.1002/cam4.6021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 04/12/2023] [Accepted: 04/20/2023] [Indexed: 05/08/2023] Open
Abstract
BACKGROUND Monepantel is an anti-helminthic drug that also has anti-cancer properties. Despite several studies over the years, the molecular target of monepantel in mammalian cells is still unknown, and its mechanism-of-action is not fully understood, though effects on cell cycle, mTOR signalling and autophagy have been implicated. METHODS Viability assays were performed on >20 solid cancer cell cells, and apoptosis assays were performed on a subset of these, including 3D cultures. Genetic deletion of BAX/BAK and ATG were used to establish roles of apoptosis and autophagy in killing activity. RNA-sequencing was performed on four cell lines after monepantel treatment, and differentially regulated genes were confirmed by Western blotting. RESULTS We showed that monepantel has anti-proliferative activity on a broad range of cancer cell lines. In some, this was associated with induction of apoptosis which was confirmed using a BAX/BAK-deficient cell line. However, proliferation is still inhibited in these cells following monepantel treatment, indicating cell-cycle disruption as the major anti-cancer effect. Previous studies have also indicated autophagic cell death occurs following monepantel treatment. We showed autophagy induction in multiple cell lines; however, deletion of a key autophagy regulator ATG7 had minimal impact on monepantel's anti-proliferative activity, suggesting autophagy is associated with, but not required for its anti-tumour effects. Transcriptomic analysis of four cell lines treated with monepantel revealed downregulation of many genes involved in the cell cycle, and upregulation of genes linked to ATF4-mediated ER stress responses, especially those involved in amino-acid metabolism and protein synthesis. CONCLUSIONS As these outcomes are all associated with mTOR signalling, cell cycle and autophagy, we now provide a likely triggering mechanism for the anti-cancer activity of monepantel.
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Affiliation(s)
- Tiffany J Harris
- Olivia Newton-John Cancer Research Institute, Heidelberg, Victoria, Australia
- School of Cancer Medicine, La Trobe University, Bundoora, Victoria, Australia
| | - Yang Liao
- Olivia Newton-John Cancer Research Institute, Heidelberg, Victoria, Australia
- School of Cancer Medicine, La Trobe University, Bundoora, Victoria, Australia
| | - Wei Shi
- Olivia Newton-John Cancer Research Institute, Heidelberg, Victoria, Australia
- School of Cancer Medicine, La Trobe University, Bundoora, Victoria, Australia
| | - Marco Evangelista
- Olivia Newton-John Cancer Research Institute, Heidelberg, Victoria, Australia
- School of Cancer Medicine, La Trobe University, Bundoora, Victoria, Australia
| | - Bhupinder Pal
- Olivia Newton-John Cancer Research Institute, Heidelberg, Victoria, Australia
- School of Cancer Medicine, La Trobe University, Bundoora, Victoria, Australia
| | - Hamsa Puthalakath
- Department of Biochemistry and Chemistry, School of Agriculture, Biomedicine and Environment, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia
| | | | - Richard Mollard
- PharmAust Ltd, Claremont, Australia
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - John M Mariadason
- Olivia Newton-John Cancer Research Institute, Heidelberg, Victoria, Australia
- School of Cancer Medicine, La Trobe University, Bundoora, Victoria, Australia
| | - Erinna F Lee
- Olivia Newton-John Cancer Research Institute, Heidelberg, Victoria, Australia
- School of Cancer Medicine, La Trobe University, Bundoora, Victoria, Australia
- Department of Biochemistry and Chemistry, School of Agriculture, Biomedicine and Environment, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia
| | - Walter D Fairlie
- Olivia Newton-John Cancer Research Institute, Heidelberg, Victoria, Australia
- School of Cancer Medicine, La Trobe University, Bundoora, Victoria, Australia
- Department of Biochemistry and Chemistry, School of Agriculture, Biomedicine and Environment, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia
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9
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Gutiérrez-Ballesteros F, Morales-Reyes J, Fernández D, Geisse A, Arcaya A, Flores-Santibañez F, Bono MR, Osorio F. Normal tissue homeostasis and impairment of selective inflammatory responses in dendritic cells deficient for ATF6α. Front Cell Dev Biol 2023; 11:1089728. [PMID: 37025177 PMCID: PMC10070697 DOI: 10.3389/fcell.2023.1089728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 03/08/2023] [Indexed: 04/08/2023] Open
Abstract
The initiation of adaptive immunity relies on the performance of dendritic cells (DCs), which are specialized leukocytes with professional antigen presenting capabilities. As such, the molecular mechanisms safeguarding DC homeostasis are matter of intense research. Sensors of the unfolded protein response (UPR) of the endoplasmic reticulum, a three-pronged signaling pathway that maintains the fidelity of the cellular proteome, have emerged as regulators of DC biology. The archetypical example is the IRE1/XBP1s axis, which supports DC development and survival of the conventional type 1 DC (cDC1) subtype. However, the role of additional UPR sensors in DC biology, such as the ATF6α branch, has not been clearly elucidated. Even though Xbp1 is transcriptionally induced by ATF6α under ER stress, it is unclear if cDCs also co-opt the ATF6α branch in tissues. Here, we examine the role of ATF6α in cDC homeostasis in vivo and upon innate stimulation in vitro. In steady state, animals lacking ATF6α in CD11c+ cells (Itgax Cre x Atf6 fl/fl mice) display normal cDC frequencies in spleen, intestine, liver, and lung. Also, ATF6α deficient cDCs express normal levels of Xbp1 mRNA and additional UPR components. However, a reduction of lung monocytes is observed in Itgax Cre x Atf6 fl/fl conditional deficient animals suggesting that ATF6α may play a role in the biology of monocyte subsets. Notably, in settings of DC activation, ATF6α contributes to the production of IL-12 and IL-6 to inflammatory stimuli. Thus, although ATF6α may be dispensable for tissue cDC homeostasis in steady state, the transcription factor plays a role in the acquisition of selective immunogenic features by activated DCs.
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Affiliation(s)
- Francisca Gutiérrez-Ballesteros
- Laboratory of Immunology and Cellular Stress, Immunology Program, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Jonathan Morales-Reyes
- Laboratory of Immunology and Cellular Stress, Immunology Program, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Dominique Fernández
- Laboratory of Immunology and Cellular Stress, Immunology Program, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Antonia Geisse
- Laboratory of Immunology and Cellular Stress, Immunology Program, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Amada Arcaya
- Laboratory of Immunology and Cellular Stress, Immunology Program, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Felipe Flores-Santibañez
- Laboratory of Immunology and Cellular Stress, Immunology Program, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Santiago, Chile
| | - María Rosa Bono
- Immunology Laboratory, Biology Department, Faculty of Sciences, University of Chile, Santiago, Chile
| | - Fabiola Osorio
- Laboratory of Immunology and Cellular Stress, Immunology Program, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Santiago, Chile
- *Correspondence: Fabiola Osorio,
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10
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Huang Q, Chen Y, Zhang Z, Xue Z, Hua Z, Luo X, Li Y, Lu C, Lu A, Liu Y. The endoplasmic reticulum participated in drug metabolic toxicity. Cell Biol Toxicol 2022; 38:945-961. [PMID: 35040016 DOI: 10.1007/s10565-021-09689-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 12/07/2021] [Indexed: 01/25/2023]
Abstract
Covalent binding of reactive metabolites formed by drug metabolic activation with biological macromolecules is considered to be an important mechanism of drug metabolic toxicity. Recent studies indicate that the endoplasmic reticulum (ER) could play an important role in drug toxicity by participating in the metabolic activation of drugs and could be a primarily attacked target by reactive metabolites. In this article, we summarize the generation and mechanism of reactive metabolites in ER stress and their associated cell death and inflammatory cascade, as well as the systematic modulation of unfolded protein response (UPR)-mediated adaptive pathways.
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Affiliation(s)
- Qingcai Huang
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Youwen Chen
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Zhengjia Zhang
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Zeyu Xue
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Zhenglai Hua
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Xinyi Luo
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Yang Li
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Cheng Lu
- Institute of Basic Research in Clinical Medicine, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | - Aiping Lu
- School of Chinese Medicine, Hong Kong Baptist University, Kowloon, Hong Kong, China
| | - Yuanyan Liu
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing, 100029, China.
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11
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Zhou L, Shen H, Li X, Wang H. Endoplasmic reticulum stress in innate immune cells - a significant contribution to non-alcoholic fatty liver disease. Front Immunol 2022; 13:951406. [PMID: 35958574 PMCID: PMC9361020 DOI: 10.3389/fimmu.2022.951406] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 06/28/2022] [Indexed: 12/12/2022] Open
Abstract
Liver disease and its complications affect millions of people worldwide. NAFLD (non-alcoholic fatty liver disease) is the liver disease associated with metabolic dysfunction and consists of four stages: steatosis with or without mild inflammation (NAFLD), non-alcoholic steatohepatitis (NASH), fibrosis, and cirrhosis. With increased necroinflammation and progression of liver fibrosis, NAFLD may progress to cirrhosis or even hepatocellular carcinoma. Although the underlying mechanisms have not been clearly elucidated in detail, what is clear is that complex immune responses are involved in the pathogenesis of NASH, activation of the innate immune system is critically involved in triggering and amplifying hepatic inflammation and fibrosis in NAFLD/NASH. Additionally, disruption of endoplasmic reticulum (ER) homeostasis in cells, also known as ER stress, triggers the unfolded protein response (UPR) which has been shown to be involved to inflammation and apoptosis. To further develop the prevention and treatment of NAFLD/NASH, it is imperative to clarify the relationship between NAFLD/NASH and innate immune cells and ER stress. As such, this review focuses on innate immune cells and their ER stress in the occurrence of NAFLD and the progression of cirrhosis.
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Affiliation(s)
- Liangliang Zhou
- Department of Oncology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
- Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Anhui Medical University, Hefei, China
| | - Haiyuan Shen
- Department of Oncology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
- Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Anhui Medical University, Hefei, China
| | - Xiaofeng Li
- Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Anhui Medical University, Hefei, China
- Anhui Institute of Innovative Drugs, School of Pharmacy, Anhui Medical University, Hefei, China
| | - Hua Wang
- Department of Oncology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
- Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Anhui Medical University, Hefei, China
- *Correspondence: Hua Wang,
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12
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Miglioranza Scavuzzi B, Holoshitz J. Endoplasmic Reticulum Stress, Oxidative Stress, and Rheumatic Diseases. Antioxidants (Basel) 2022; 11:1306. [PMID: 35883795 PMCID: PMC9312221 DOI: 10.3390/antiox11071306] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 06/27/2022] [Accepted: 06/27/2022] [Indexed: 12/10/2022] Open
Abstract
BACKGROUND The endoplasmic reticulum (ER) is a multi-functional organelle responsible for cellular homeostasis, protein synthesis, folding and secretion. It has been increasingly recognized that the loss of ER homeostasis plays a central role in the development of autoimmune inflammatory disorders, such as rheumatic diseases. Purpose/Main contents: Here, we review current knowledge of the contribution of ER stress to the pathogenesis of rheumatic diseases, with a focus on rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). We also review the interplay between protein folding and formation of reactive oxygen species (ROS), where ER stress induces oxidative stress (OS), which further aggravates the accumulation of misfolded proteins and oxidation, in a vicious cycle. Intervention studies targeting ER stress and oxidative stress in the context of rheumatic diseases are also reviewed. CONCLUSIONS Loss of ER homeostasis is a significant factor in the pathogeneses of RA and SLE. Targeting ER stress, unfolded protein response (UPR) pathways and oxidative stress in these diseases both in vitro and in animal models have shown promising results and deserve further investigation.
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Affiliation(s)
| | - Joseph Holoshitz
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA;
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13
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Lee K, Chan JY, Liang C, Ip CK, Shi YC, Herzog H, Hughes WE, Bensellam M, Delghingaro-Augusto V, Koina ME, Nolan CJ, Laybutt DR. XBP1 maintains beta cell identity, represses beta-to-alpha cell transdifferentiation and protects against diabetic beta cell failure during metabolic stress in mice. Diabetologia 2022; 65:984-996. [PMID: 35316840 PMCID: PMC9076738 DOI: 10.1007/s00125-022-05669-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 12/13/2021] [Indexed: 01/01/2023]
Abstract
AIMS/HYPOTHESIS Pancreatic beta cell dedifferentiation, transdifferentiation into other islet cells and apoptosis have been implicated in beta cell failure in type 2 diabetes, although the mechanisms are poorly defined. The endoplasmic reticulum stress response factor X-box binding protein 1 (XBP1) is a major regulator of the unfolded protein response. XBP1 expression is reduced in islets of people with type 2 diabetes, but its role in adult differentiated beta cells is unclear. Here, we assessed the effects of Xbp1 deletion in adult beta cells and tested whether XBP1-mediated unfolded protein response makes a necessary contribution to beta cell compensation in insulin resistance states. METHODS Mice with inducible beta cell-specific Xbp1 deletion were studied under normal (chow diet) or metabolic stress (high-fat diet or obesity) conditions. Glucose tolerance, insulin secretion, islet gene expression, alpha cell mass, beta cell mass and apoptosis were assessed. Lineage tracing was used to determine beta cell fate. RESULTS Deletion of Xbp1 in adult mouse beta cells led to beta cell dedifferentiation, beta-to-alpha cell transdifferentiation and increased alpha cell mass. Cell lineage-specific analyses revealed that Xbp1 deletion deactivated beta cell identity genes (insulin, Pdx1, Nkx6.1, Beta2, Foxo1) and derepressed beta cell dedifferentiation (Aldh1a3) and alpha cell (glucagon, Arx, Irx2) genes. Xbp1 deletion in beta cells of obese ob/ob or high-fat diet-fed mice triggered diabetes and worsened glucose intolerance by disrupting insulin secretory capacity. Furthermore, Xbp1 deletion increased beta cell apoptosis under metabolic stress conditions by attenuating the antioxidant response. CONCLUSIONS/INTERPRETATION These findings indicate that XBP1 maintains beta cell identity, represses beta-to-alpha cell transdifferentiation and is required for beta cell compensation and prevention of diabetes in insulin resistance states.
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Affiliation(s)
- Kailun Lee
- Garvan Institute of Medical Research, St Vincent's Clinical School, UNSW Sydney, Darlinghurst, NSW, Australia
| | - Jeng Yie Chan
- Garvan Institute of Medical Research, St Vincent's Clinical School, UNSW Sydney, Darlinghurst, NSW, Australia
| | - Cassandra Liang
- Garvan Institute of Medical Research, St Vincent's Clinical School, UNSW Sydney, Darlinghurst, NSW, Australia
| | - Chi Kin Ip
- Garvan Institute of Medical Research, St Vincent's Clinical School, UNSW Sydney, Darlinghurst, NSW, Australia
| | - Yan-Chuan Shi
- Garvan Institute of Medical Research, St Vincent's Clinical School, UNSW Sydney, Darlinghurst, NSW, Australia
| | - Herbert Herzog
- Garvan Institute of Medical Research, St Vincent's Clinical School, UNSW Sydney, Darlinghurst, NSW, Australia
| | - William E Hughes
- Garvan Institute of Medical Research, St Vincent's Clinical School, UNSW Sydney, Darlinghurst, NSW, Australia
| | - Mohammed Bensellam
- Garvan Institute of Medical Research, St Vincent's Clinical School, UNSW Sydney, Darlinghurst, NSW, Australia
- Secteur des sciences de la santé, Institut de recherche expérimentale et clinique, Pôle d'endocrinologie, diabète et nutrition, Université catholique de Louvain, Brussels, Belgium
| | - Viviane Delghingaro-Augusto
- Medical School and John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia
| | - Mark E Koina
- ACT Pathology, Canberra Health Services, Garran, ACT, Australia
| | - Christopher J Nolan
- Medical School and John Curtin School of Medical Research, Australian National University, Canberra, ACT, Australia
- Department of Endocrinology, The Canberra Hospital, Garran, ACT, Australia
| | - D Ross Laybutt
- Garvan Institute of Medical Research, St Vincent's Clinical School, UNSW Sydney, Darlinghurst, NSW, Australia.
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14
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Liu Y, Ding R, Xu Z, Xue Y, Zhang D, Zhang Y, Li W, Li X. Roles and Mechanisms of the Protein Quality Control System in Alzheimer's Disease. Int J Mol Sci 2021; 23:345. [PMID: 35008771 PMCID: PMC8745298 DOI: 10.3390/ijms23010345] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/26/2021] [Accepted: 12/27/2021] [Indexed: 12/11/2022] Open
Abstract
Alzheimer's disease (AD) is characterized by the deposition of senile plaques (SPs) and the formation of neurofibrillary tangles (NTFs), as well as neuronal dysfunctions in the brain, but in fact, patients have shown a sustained disease progression for at least 10 to 15 years before these pathologic biomarkers can be detected. Consequently, as the most common chronic neurological disease in the elderly, the challenge of AD treatment is that it is short of effective biomarkers for early diagnosis. The protein quality control system is a collection of cellular pathways that can recognize damaged proteins and thereby modulate their turnover. Abundant evidence indicates that the accumulation of abnormal proteins in AD is closely related to the dysfunction of the protein quality control system. In particular, it is the synthesis, degradation, and removal of essential biological components that have already changed in the early stage of AD, which further encourages us to pay more attention to the protein quality control system. The review mainly focuses on the endoplasmic reticulum system (ERS), autophagy-lysosome system (ALS) and the ubiquitin-proteasome system (UPS), and deeply discusses the relationship between the protein quality control system and the abnormal proteins of AD, which can not only help us to understand how and why the complex regulatory system becomes malfunctional during AD progression, but also provide more novel therapeutic strategies to prevent the development of AD.
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Affiliation(s)
| | | | | | | | | | | | | | - Xing Li
- Department of Nutrition and Food Hygiene, College of Public Health, Zhengzhou University, Zhengzhou 450001, China; (Y.L.); (R.D.); (Z.X.); (Y.X.); (D.Z.); (Y.Z.); (W.L.)
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15
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Han L, Xu Y, Shi Y. Molecular Mechanism of the ATF6α/S1P/S2P Signaling Pathway in Hippocampal Neuronal Apoptosis in SPS Rats. J Mol Neurosci 2021; 71:2487-2499. [PMID: 33738762 DOI: 10.1007/s12031-021-01823-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 02/25/2021] [Indexed: 11/30/2022]
Abstract
Apoptosis of hippocampal neurons is one of the mechanisms of hippocampal atrophy in posttraumatic stress disorder (PTSD), and it is also an important cause of memory impairment in PTSD patients. Endoplasmic reticulum stress (ERS) mediated by activated transcription factor 6α (ATF6α)/site 1 protease (S1P)/S2P is involved in cell apoptosis, but it is not clear whether it is involved in hippocampal neuron apoptosis caused by PTSD. A PTSD rat model was constructed by the single prolonged stress (SPS) method. The study was divided into three parts. Experiment 1 included the control group, SPS 1 d group, SPS 7 d group, and SPS 14 d group. Experiment 2 included the control group, SPS 7 d group, SPS 7 d + AEBSF group, and control + AEBSF group. (4-(2-Aminoethyl)benzenesulfonyl fluoride hydrochloride (AEBSF) is an ATF6α pathway inhibitor). Experiment 3 included the control group, SPS 4 d group, SPS 4 d + AEBSF group, and control + AEBSF group. The protein and mRNA expression levels of ATF6α, glucose-regulated protein (GRP78), S1P, S2P, C/EBP homologous protein (CHOP), and caspase-12 in the hippocampus of PTSD rats were detected by immunohistochemistry, Western blotting and qRT-PCR. Apoptosis of hippocampal neurons was detected by TUNEL staining. In experiment 1, the protein and mRNA expression of ATF6α and GRP78 increased gradually in the SPS 1 d group and the SPS 7 d group but decreased in the SPS 14 d group (P < 0.01). In experiment 2, compared with that in the control group, the protein and mRNA expression of ATF6α, GRP78, S1P, S2P, CHOP, and caspase-12 and the apoptosis rate were significantly increased in the SPS 7 d group (P < 0.01). However, the protein and mRNA expression of ATF6α, GRP78, S1P, S2P, CHOP, and caspase-12 and the apoptosis rate were significantly decreased after AEBSF pretreatment (P < 0.01). In experiment 3, compared with that in the control group, the protein and mRNA expression of ATF6α, GRP78, S1P, S2P, CHOP, and caspase-12 and the apoptosis rate were increased in the SPS 14 d group (P < 0.05). However, the protein and mRNA expression of ATF6α, GRP78, S1P, S2P, CHOP, and caspase-12 and the apoptosis rate were decreased after AEBSF pretreatment (P < 0.05). SPS induced apoptosis of hippocampal neurons by activating ERS mediated by ATF6α, suggesting that ERS-induced apoptosis is involved in the occurrence of PTSD.
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Affiliation(s)
- Liang Han
- PTSD Laboratory, Department of Histology and Embryology, School of Basic Medicine, China Medical University, Shenyang, China
- Department of Thoracic Surgery, Third Affiliated Hospital of Jinzhou Medical University, Jinzhou, China
| | - Yanhao Xu
- PTSD Laboratory, Department of Histology and Embryology, School of Basic Medicine, China Medical University, Shenyang, China
| | - Yuxiu Shi
- PTSD Laboratory, Department of Histology and Embryology, School of Basic Medicine, China Medical University, Shenyang, China.
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16
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Huang MY, Wan DW, Deng J, Guo WJ, Huang Y, Chen H, Xu DL, Jiang ZG, Xue Y, He YH. Downregulation of RIP3 Improves the Protective Effect of ATF6 in an Acute Liver Injury Model. BIOMED RESEARCH INTERNATIONAL 2021; 2021:8717565. [PMID: 34778458 PMCID: PMC8589516 DOI: 10.1155/2021/8717565] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 09/28/2021] [Accepted: 10/11/2021] [Indexed: 01/29/2023]
Abstract
BACKGROUND Activating transcription factor 6 (ATF6) and receptor-interacting protein 3 (RIP3) are important signaling proteins in endoplasmic reticulum (ER) stress and necroptosis, respectively. However, their regulatory relationship and clinical significance are unknown. We investigate the impact of ATF6 on RIP3 expression, and its role in hepatocyte necroptosis in an acute liver injury model. METHODS In vivo and in vitro experiments were carried out. LO2 cells were treated with thapsigargin (TG). In vivo, male BALB/c mice were treated with carbon tetrachloride (CCl4, 1 mL/kg) or tunicamycin (TM, 2 mg/kg). Then, the impact of ATF6 or RIP3 silencing on liver injury, hepatocyte necroptosis, and ER stress-related protein expression was examined. RESULTS TG induced ER stress and necroptosis and ATF6 and RIP3 expression in LO2 cells. The knockdown of ATF6 significantly decreased RIP3 expression (p < 0.05) and increased ER stress and necroptosis. The downregulation of RIP3 significantly reduced necroptosis and ER stress (p < 0.05). Similar results were observed in CCl4 or the TM-induced mouse model. The knockdown of ATF6 significantly decreased CCl4-induced RIP3 expression and increased liver injury, necroptosis, and ER stress in mice livers (p < 0.05). In contrast, the downregulation of RIP3 significantly reduced liver injury, hepatocyte necroptosis, and ER stress. CONCLUSIONS Hepatocyte ATF6 has multiple roles in acute liver injury. It reduces hepatocyte necroptosis via negative feedback regulation of ER stress. In addition, ATF6 can upregulate the expression of RIP3, which is not helpful to the recovery process. However, downregulating RIP3 reduces hepatocyte necroptosis by promoting the alleviation of ER stress. The findings suggest that RIP3 could be a plausible target for the treatment of liver injury.
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Affiliation(s)
- Mei-Ying Huang
- Department of Pediatrics, The Affiliated Hospital of Zunyi Medical University, Zunyi, 563000 Guizhou, China
| | - Dian-Wei Wan
- Department of Infectious Diseases, The Affiliated Hospital of Zunyi Medical University, Zunyi, 563000 Guizhou, China
| | - Jie Deng
- Department of Infectious Diseases, The Affiliated Hospital of Zunyi Medical University, Zunyi, 563000 Guizhou, China
| | - Wen-Jie Guo
- Department of Infectious Diseases, The Affiliated Hospital of Zunyi Medical University, Zunyi, 563000 Guizhou, China
| | - Yue Huang
- Department of Infectious Diseases, The Affiliated Hospital of Zunyi Medical University, Zunyi, 563000 Guizhou, China
| | - Huan Chen
- Department of Infectious Diseases, The Affiliated Hospital of Zunyi Medical University, Zunyi, 563000 Guizhou, China
| | - De-Lin Xu
- Department of Cell Biology, Zunyi Medical University, Zunyi, 563099 Guizhou, China
| | - Zhi-Gang Jiang
- School of Public Health, Zunyi Medical University, Zunyi, 563099 Guizhou, China
| | - Yuan Xue
- Department of Liver Diseases, The Third People's Hospital of Changzhou, Changzhou, 213000 Jiangsu Province, China
| | - Yi-Huai He
- Department of Infectious Diseases, The Affiliated Hospital of Zunyi Medical University, Zunyi, 563000 Guizhou, China
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17
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Strong A, March ME, Cardinale CJ, Kim SE, Merves J, Whitworth H, Raffini L, Larosa C, Copelovitch L, Hou C, Slater D, Vaccaro C, Watson D, Zackai EH, Billheimer J, Hakonarson H. A novel MBTPS2 variant associated with BRESHECK syndrome impairs sterol-regulated transcription and the endoplasmic reticulum stress response. Am J Med Genet A 2021; 188:463-472. [PMID: 34655156 PMCID: PMC9293288 DOI: 10.1002/ajmg.a.62537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/22/2021] [Accepted: 09/29/2021] [Indexed: 11/11/2022]
Abstract
Ichthyosis follicularis, atrichia, and photophobia syndrome (IFAP syndrome) is a rare, X-linked disorder caused by pathogenic variants in membrane-bound transcription factor protease, site 2 (MBTPS2). Pathogenic MBTPS2 variants also cause BRESHECK syndrome, characterized by the IFAP triad plus intellectual disability and multiple congenital anomalies. Here we present a patient with ichthyosis, sparse hair, pulmonic stenosis, kidney dysplasia, hypospadias, growth failure, thrombocytopenia, anemia, bone marrow fibrosis, and chronic diarrhea found by research-based exome sequencing to harbor a novel, maternally inherited MBTPS2 missense variant (c.766 G>A; (p.Val256Leu)). In vitro modeling supports variant pathogenicity, with impaired cell growth in cholesterol-depleted media, attenuated activation of the sterol regulatory element-binding protein pathway, and failure to activate the endoplasmic reticulum stress response pathway. Our case expands both the genetic and phenotypic spectrum of BRESHECK syndrome to include a novel MBTPS2 variant and cytopenias, bone marrow fibrosis, and chronic diarrhea.
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Affiliation(s)
- Alanna Strong
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.,The Center for Applied Genomics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Michael E March
- The Center for Applied Genomics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Christopher J Cardinale
- The Center for Applied Genomics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Sophia E Kim
- The Center for Applied Genomics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Jamie Merves
- Division of Gastroenterology, Hepatology and Nutrition, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.,Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Hilary Whitworth
- Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Leslie Raffini
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Christopher Larosa
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Division of Nephrology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Lawrence Copelovitch
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Division of Nephrology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Cuiping Hou
- The Center for Applied Genomics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Diana Slater
- The Center for Applied Genomics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Courtney Vaccaro
- The Center for Applied Genomics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Deborah Watson
- The Center for Applied Genomics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Elaine H Zackai
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.,Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jeffrey Billheimer
- Division of Translational Medicine and Human Genetics, Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Hakon Hakonarson
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.,The Center for Applied Genomics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.,Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Division of Pulmonary Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
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18
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Snyder JT, Darko C, Sharma RB, Alonso LC. Endoplasmic Reticulum Stress Induced Proliferation Remains Intact in Aging Mouse β-Cells. Front Endocrinol (Lausanne) 2021; 12:734079. [PMID: 34531828 PMCID: PMC8438540 DOI: 10.3389/fendo.2021.734079] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 08/05/2021] [Indexed: 02/06/2023] Open
Abstract
Aging is associated with loss of proliferation of the insulin-secreting β-cell, a possible contributing factor to the increased prevalence of type 2 diabetes in the elderly. Our group previously discovered that moderate endoplasmic reticulum (ER) stress occurring during glucose exposure increases the adaptive β-cell proliferation response. Specifically, the ATF6α arm of the tripartite Unfolded Protein Response (UPR) promotes β-cell replication in glucose excess conditions. We hypothesized that β-cells from older mice have reduced proliferation due to aberrant UPR signaling or an impaired proliferative response to ER stress or ATF6α activation. To investigate, young and old mouse islet cells were exposed to high glucose with low-dose thapsigargin or activation of overexpressed ATF6α, and β-cell proliferation was quantified by BrdU incorporation. UPR pathway activation was compared by qPCR of target genes and semi-quantitative Xbp1 splicing assay. Intriguingly, although old β-cells had reduced proliferation in high glucose compared to young β-cells, UPR activation and induction of proliferation in response to low-dose thapsigargin or ATF6α activation in high glucose were largely similar between young and old. These results suggest that loss of UPR-led adaptive proliferation does not explain the reduced cell cycle entry in old β-cells, and raise the exciting possibility that future therapies that engage adaptive UPR could increase β-cell number through proliferation even in older individuals.
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Affiliation(s)
- Jarin T. Snyder
- Graduate School of Biomedical Sciences, UMass Medical School, Worcester, MA, United States
| | - Christine Darko
- Division of Endocrinology, Diabetes and Metabolism and the Weill Center for Metabolic Health, Weill Cornell Medicine, New York, NY, United States
| | - Rohit B. Sharma
- Division of Endocrinology, Diabetes and Metabolism and the Weill Center for Metabolic Health, Weill Cornell Medicine, New York, NY, United States
| | - Laura C. Alonso
- Division of Endocrinology, Diabetes and Metabolism and the Weill Center for Metabolic Health, Weill Cornell Medicine, New York, NY, United States
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19
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Charbord J, Ren L, Sharma RB, Johansson A, Ågren R, Chu L, Tworus D, Schulz N, Charbord P, Stewart AF, Wang P, Alonso LC, Andersson O. In vivo screen identifies a SIK inhibitor that induces β cell proliferation through a transient UPR. Nat Metab 2021; 3:682-700. [PMID: 34031592 PMCID: PMC9756392 DOI: 10.1038/s42255-021-00391-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 04/14/2021] [Indexed: 02/03/2023]
Abstract
It is known that β cell proliferation expands the β cell mass during development and under certain hyperglycemic conditions in the adult, a process that may be used for β cell regeneration in diabetes. Here, through a new high-throughput screen using a luminescence ubiquitination-based cell cycle indicator (LUCCI) in zebrafish, we identify HG-9-91-01 as a driver of proliferation and confirm this effect in mouse and human β cells. HG-9-91-01 is an inhibitor of salt-inducible kinases (SIKs), and overexpression of Sik1 specifically in β cells blocks the effect of HG-9-91-01 on β cell proliferation. Single-cell transcriptomic analyses of mouse β cells demonstrate that HG-9-91-01 induces a wave of activating transcription factor (ATF)6-dependent unfolded protein response (UPR) before cell cycle entry. Importantly, the UPR wave is not associated with an increase in insulin expression. Additional mechanistic studies indicate that HG-9-91-01 induces multiple signalling effectors downstream of SIK inhibition, including CRTC1, CRTC2, ATF6, IRE1 and mTOR, which integrate to collectively drive β cell proliferation.
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Affiliation(s)
- Jérémie Charbord
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Lipeng Ren
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Rohit B Sharma
- Division of Endocrinology, Diabetes and Metabolism, Weill Cornell Medicine, New York, NY, USA
| | - Anna Johansson
- Department of Cell and Molecular Biology, National Bioinformatics Infrastructure Sweden, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Rasmus Ågren
- Department of Biology and Biological Engineering, National Bioinformatics Infrastructure Sweden, Science for Life Laboratory, Chalmers University of Technology, Göteborg, Sweden
| | - Lianhe Chu
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Dominika Tworus
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Nadja Schulz
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Pierre Charbord
- Sorbonne Université, Institut de Biologie Paris-Seine, CNRS UMR 7622, Inserm, Paris, France
| | - Andrew F Stewart
- Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Peng Wang
- Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Laura C Alonso
- Division of Endocrinology, Diabetes and Metabolism, Weill Cornell Medicine, New York, NY, USA
| | - Olov Andersson
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden.
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20
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Šrámek J, Němcová-Fürstová V, Kovář J. Molecular Mechanisms of Apoptosis Induction and Its Regulation by Fatty Acids in Pancreatic β-Cells. Int J Mol Sci 2021; 22:4285. [PMID: 33924206 PMCID: PMC8074590 DOI: 10.3390/ijms22084285] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/09/2021] [Accepted: 04/16/2021] [Indexed: 02/06/2023] Open
Abstract
Pancreatic β-cell failure and death contribute significantly to the pathogenesis of type 2 diabetes. One of the main factors responsible for β-cell dysfunction and subsequent cell death is chronic exposure to increased concentrations of FAs (fatty acids). The effect of FAs seems to depend particularly on the degree of their saturation. Saturated FAs induce apoptosis in pancreatic β-cells, whereas unsaturated FAs are well tolerated and are even capable of inhibiting the pro-apoptotic effect of saturated FAs. Molecular mechanisms of apoptosis induction by saturated FAs in β-cells are not completely elucidated. Saturated FAs induce ER stress, which in turn leads to activation of all ER stress pathways. When ER stress is severe or prolonged, apoptosis is induced. The main mediator seems to be the CHOP transcription factor. Via regulation of expression/activity of pro- and anti-apoptotic Bcl-2 family members, and potentially also through the increase in ROS production, CHOP switches on the mitochondrial pathway of apoptosis induction. ER stress signalling also possibly leads to autophagy signalling, which may activate caspase-8. Saturated FAs activate or inhibit various signalling pathways, i.e., p38 MAPK signalling, ERK signalling, ceramide signalling, Akt signalling and PKCδ signalling. This may lead to the activation of the mitochondrial pathway of apoptosis, as well. Particularly, the inhibition of the pro-survival Akt signalling seems to play an important role. This inhibition may be mediated by multiple pathways (e.g., ER stress signalling, PKCδ and ceramide) and could also consequence in autophagy signalling. Experimental evidence indicates the involvement of certain miRNAs in mechanisms of FA-induced β-cell apoptosis, as well. In the rather rare situations when unsaturated FAs are also shown to be pro-apoptotic, the mechanisms mediating this effect in β-cells seem to be the same as for saturated FAs. To conclude, FA-induced apoptosis rather appears to be preceded by complex cross talks of multiple signalling pathways. Some of these pathways may be regulated by decreased membrane fluidity due to saturated FA incorporation. Few data are available concerning molecular mechanisms mediating the protective effect of unsaturated FAs on the effect of saturated FAs. It seems that the main possible mechanism represents a rather inhibitory intervention into saturated FA-induced pro-apoptotic signalling than activation of some pro-survival signalling pathway(s) or metabolic interference in β-cells. This inhibitory intervention may be due to an increase of membrane fluidity.
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Affiliation(s)
- Jan Šrámek
- Department of Biochemistry, Cell and Molecular Biology & Center for Research of Diabetes, Metabolism and Nutrition, Third Faculty of Medicine, Charles University, Ruská 87, 100 00 Prague, Czech Republic;
| | - Vlasta Němcová-Fürstová
- Department of Biochemistry, Cell and Molecular Biology & Center for Research of Diabetes, Metabolism and Nutrition, Third Faculty of Medicine, Charles University, Ruská 87, 100 00 Prague, Czech Republic;
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21
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Marsh KG, Arrieta A, Thuerauf DJ, Blackwood EA, MacDonnell L, Glembotski CC. The peroxisomal enzyme, FAR1, is induced during ER stress in an ATF6-dependent manner in cardiac myocytes. Am J Physiol Heart Circ Physiol 2021; 320:H1813-H1821. [PMID: 33666503 DOI: 10.1152/ajpheart.00999.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Although peroxisomes have been extensively studied in other cell types, their presence and function have gone virtually unexamined in cardiac myocytes. Here, in neonatal rat ventricular myocytes (NRVM) we showed that several known peroxisomal proteins co-localize to punctate structures with a morphology typical of peroxisomes. Surprisingly, we found that the peroxisomal protein, fatty acyl-CoA reductase 1 (FAR1), was upregulated by pharmacological and pathophysiological ER stress induced by tunicamycin (TM) and simulated ischemia-reperfusion (sI/R), respectively. Moreover, FAR1 induction in NRVM was mediated by the ER stress sensor, activating transcription factor 6 (ATF6). Functionally, FAR1 knockdown reduced myocyte death during oxidative stress induced by either sI/R or hydrogen peroxide (H2O2). Thus, Far1 is an ER stress-inducible gene, which encodes a protein that localizes to peroxisomes of cardiac myocytes, where it reduces myocyte viability during oxidative stress. Since FAR1 is critical for plasmalogen synthesis, these results imply that plasmalogens may exert maladaptive effects on the viability of myocytes exposed to oxidative stress.NEW & NOTEWORTHY The peroxisomal enzyme, FAR1, was shown to be an ER stress- and ATF6-inducible protein that localizes to peroxisomes in cardiac myocytes. FAR1 decreases myocyte viability during oxidative stress.
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Affiliation(s)
- Kayleigh G Marsh
- San Diego State University Heart Institute and Department of Biology, San Diego State University, San Diego, California
| | - Adrian Arrieta
- San Diego State University Heart Institute and Department of Biology, San Diego State University, San Diego, California.,Department of Anesthesiology & Perioperative Medicine, David Geffen School of Medicine at University of California, Los Angeles, California
| | - Donna J Thuerauf
- San Diego State University Heart Institute and Department of Biology, San Diego State University, San Diego, California
| | - Erik A Blackwood
- San Diego State University Heart Institute and Department of Biology, San Diego State University, San Diego, California.,Department of Internal Medicine and the Center for Translational Cardiovascular Research, University of Arizona, Phoenix, Arizona
| | - Lauren MacDonnell
- San Diego State University Heart Institute and Department of Biology, San Diego State University, San Diego, California.,Department of Internal Medicine and the Center for Translational Cardiovascular Research, University of Arizona, Phoenix, Arizona
| | - Christopher C Glembotski
- San Diego State University Heart Institute and Department of Biology, San Diego State University, San Diego, California.,Department of Internal Medicine and the Center for Translational Cardiovascular Research, University of Arizona, Phoenix, Arizona
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22
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Wei J, Fang D. Endoplasmic Reticulum Stress Signaling and the Pathogenesis of Hepatocarcinoma. Int J Mol Sci 2021; 22:ijms22041799. [PMID: 33670323 PMCID: PMC7918477 DOI: 10.3390/ijms22041799] [Citation(s) in RCA: 170] [Impact Index Per Article: 56.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 02/05/2021] [Accepted: 02/08/2021] [Indexed: 12/12/2022] Open
Abstract
Hepatocellular carcinoma (HCC), also known as hepatoma, is a primary malignancy of the liver and the third leading cause of cancer mortality globally. Although much attention has focused on HCC, its pathogenesis remains largely obscure. The endoplasmic reticulum (ER) is a cellular organelle important for regulating protein synthesis, folding, modification and trafficking, and lipid metabolism. ER stress occurs when ER homeostasis is disturbed by numerous environmental, physiological, and pathological challenges. In response to ER stress due to misfolded/unfolded protein accumulation, unfolded protein response (UPR) is activated to maintain ER function for cell survival or, in cases of excessively severe ER stress, initiation of apoptosis. The liver is especially susceptible to ER stress given its protein synthesis and detoxification functions. Experimental data suggest that ER stress and unfolded protein response are involved in HCC development, aggressiveness and response to treatment. Herein, we highlight recent findings and provide an overview of the evidence linking ER stress to the pathogenesis of HCC.
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23
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Bilekova S, Sachs S, Lickert H. Pharmacological Targeting of Endoplasmic Reticulum Stress in Pancreatic Beta Cells. Trends Pharmacol Sci 2020; 42:85-95. [PMID: 33353789 DOI: 10.1016/j.tips.2020.11.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 11/20/2020] [Accepted: 11/24/2020] [Indexed: 02/06/2023]
Abstract
Diabetes is a disease with pandemic dimensions and no pharmacological treatment prevents disease progression. Dedifferentiation has been proposed to be a driver of beta-cell dysfunction in both type 1 and type 2 diabetes. Regenerative therapies aim to re-establish function in dysfunctional or dedifferentiated beta cells and restore the defective insulin secretion. Unsustainable levels of insulin production, with increased demand at disease onset, strain the beta-cell secretory machinery, leading to endoplasmic reticulum (ER) stress. Unresolved chronic ER stress is a major contributor to beta-cell loss of function and identity. Restoring ER homeostasis, enhancing ER-associated degradation of misfolded protein, and boosting chaperoning activity, are emerging therapeutic approaches for diabetes treatment.
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Affiliation(s)
- Sara Bilekova
- Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany; Technical University of Munich, Medical Faculty, Munich, Germany
| | - Stephan Sachs
- Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany; Technical University of Munich, Medical Faculty, Munich, Germany
| | - Heiko Lickert
- Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany; Technical University of Munich, Medical Faculty, Munich, Germany; Institute of Stem Cell Research, Helmholtz Zentrum München, Neuherberg, Germany.
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Sharma RB, Darko C, Alonso LC. Intersection of the ATF6 and XBP1 ER stress pathways in mouse islet cells. J Biol Chem 2020; 295:14164-14177. [PMID: 32788214 DOI: 10.1074/jbc.ra120.014173] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 08/06/2020] [Indexed: 12/20/2022] Open
Abstract
Success or failure of pancreatic beta cell adaptation to ER stress is a determinant of diabetes susceptibility. The ATF6 and IRE1/XBP1 pathways are separate ER stress-response effectors important to beta cell health and function. ATF6α. and XBP1 direct overlapping transcriptional responses in some cell types. However, the signaling dynamics and interdependence of ATF6α and XBP1 in pancreatic beta cells have not been explored. To assess pathway-specific signal onset, we performed timed exposures of primary mouse islet cells to ER stressors and measured the early transcriptional response. Comparing the time course of induction of ATF6 and XBP1 targets suggested that the two pathways have similar response dynamics. The role of ATF6α in target induction was assessed by acute knockdown using islet cells from Atf6α flox/flox mice transduced with adenovirus expressing Cre recombinase. Surprisingly, given the mild impact of chronic deletion in mice, acute ATF6α knockdown markedly reduced ATF6-pathway target gene expression under both basal and stressed conditions. Intriguingly, although ATF6α knockdown did not alter Xbp1 splicing dynamics or intensity, it did reduce induction of XBP1 targets. Inhibition of Xbp1 splicing did not decrease induction of ATF6α targets. Taken together, these data suggest that the XBP1 and ATF6 pathways are simultaneously activated in islet cells in response to acute stress and that ATF6α is required for full activation of XBP1 targets, but XBP1 is not required for activation of ATF6α targets. These observations improve understanding of the ER stress transcriptional response in pancreatic islets.
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Affiliation(s)
- Rohit B Sharma
- Division of Endocrinology, Diabetes and Metabolism, Weill Cornell Medicine, New York, New York, USA .,Weill Center for Metabolic Health, Weill Cornell Medicine, New York, New York, USA
| | - Christine Darko
- Division of Endocrinology, Diabetes and Metabolism, Weill Cornell Medicine, New York, New York, USA.,Weill Center for Metabolic Health, Weill Cornell Medicine, New York, New York, USA
| | - Laura C Alonso
- Division of Endocrinology, Diabetes and Metabolism, Weill Cornell Medicine, New York, New York, USA .,Weill Center for Metabolic Health, Weill Cornell Medicine, New York, New York, USA
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25
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Glembotski CC, Arrieta A, Blackwood EA, Stauffer WT. ATF6 as a Nodal Regulator of Proteostasis in the Heart. Front Physiol 2020; 11:267. [PMID: 32322217 PMCID: PMC7156617 DOI: 10.3389/fphys.2020.00267] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 03/09/2020] [Indexed: 12/15/2022] Open
Abstract
Proteostasis encompasses a homeostatic cellular network in all cells that maintains the integrity of the proteome, which is critical for optimal cellular function. The components of the proteostasis network include protein synthesis, folding, trafficking, and degradation. Cardiac myocytes have a specialized endoplasmic reticulum (ER) called the sarcoplasmic reticulum that is well known for its role in contractile calcium handling. However, less studied is the proteostasis network associated with the ER, which is of particular importance in cardiac myocytes because it ensures the integrity of proteins that are critical for cardiac contraction, e.g., ion channels, as well as proteins necessary for maintaining myocyte viability and interaction with other cell types, e.g., secreted hormones and growth factors. A major aspect of the ER proteostasis network is the ER unfolded protein response (UPR), which is initiated when misfolded proteins in the ER activate a group of three ER transmembrane proteins, one of which is the transcription factor, ATF6. Prior to studies in the heart, ATF6 had been shown in model cell lines to be primarily adaptive, exerting protective effects by inducing genes that encode ER proteins that fortify protein-folding in this organelle, thus establishing the canonical role for ATF6. Subsequent studies in isolated cardiac myocytes and in the myocardium, in vivo, have expanded roles for ATF6 beyond the canonical functions to include the induction of genes that encode proteins outside of the ER that do not have known functions that are obviously related to ER protein-folding. The identification of such non-canonical roles for ATF6, as well as findings that the gene programs induced by ATF6 differ depending on the stimulus, have piqued interest in further research on ATF6 as an adaptive effector in cardiac myocytes, underscoring the therapeutic potential of activating ATF6 in the heart. Moreover, discoveries of small molecule activators of ATF6 that adaptively affect the heart, as well as other organs, in vivo, have expanded the potential for development of ATF6-based therapeutics. This review focuses on the ATF6 arm of the ER UPR and its effects on the proteostasis network in the myocardium.
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Affiliation(s)
- Christopher C Glembotski
- Department of Biology, College of Sciences, San Diego State University Heart Institute, San Diego State University, San Diego, CA, United States
| | - Adrian Arrieta
- Department of Biology, College of Sciences, San Diego State University Heart Institute, San Diego State University, San Diego, CA, United States
| | - Erik A Blackwood
- Department of Biology, College of Sciences, San Diego State University Heart Institute, San Diego State University, San Diego, CA, United States
| | - Winston T Stauffer
- Department of Biology, College of Sciences, San Diego State University Heart Institute, San Diego State University, San Diego, CA, United States
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