1
|
Zhang SX, Wang JJ, Starr CR, Lee EJ, Park KS, Zhylkibayev A, Medina A, Lin JH, Gorbatyuk M. The endoplasmic reticulum: Homeostasis and crosstalk in retinal health and disease. Prog Retin Eye Res 2024; 98:101231. [PMID: 38092262 PMCID: PMC11056313 DOI: 10.1016/j.preteyeres.2023.101231] [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: 08/21/2023] [Revised: 12/05/2023] [Accepted: 12/06/2023] [Indexed: 12/19/2023]
Abstract
The endoplasmic reticulum (ER) is the largest intracellular organelle carrying out a broad range of important cellular functions including protein biosynthesis, folding, and trafficking, lipid and sterol biosynthesis, carbohydrate metabolism, and calcium storage and gated release. In addition, the ER makes close contact with multiple intracellular organelles such as mitochondria and the plasma membrane to actively regulate the biogenesis, remodeling, and function of these organelles. Therefore, maintaining a homeostatic and functional ER is critical for the survival and function of cells. This vital process is implemented through well-orchestrated signaling pathways of the unfolded protein response (UPR). The UPR is activated when misfolded or unfolded proteins accumulate in the ER, a condition known as ER stress, and functions to restore ER homeostasis thus promoting cell survival. However, prolonged activation or dysregulation of the UPR can lead to cell death and other detrimental events such as inflammation and oxidative stress; these processes are implicated in the pathogenesis of many human diseases including retinal disorders. In this review manuscript, we discuss the unique features of the ER and ER stress signaling in the retina and retinal neurons and describe recent advances in the research to uncover the role of ER stress signaling in neurodegenerative retinal diseases including age-related macular degeneration, inherited retinal degeneration, achromatopsia and cone diseases, and diabetic retinopathy. In some chapters, we highlight the complex interactions between the ER and other intracellular organelles focusing on mitochondria and illustrate how ER stress signaling regulates common cellular stress pathways such as autophagy. We also touch upon the integrated stress response in retinal degeneration and diabetic retinopathy. Finally, we provide an update on the current development of pharmacological agents targeting the UPR response and discuss some unresolved questions and knowledge gaps to be addressed by future research.
Collapse
Affiliation(s)
- Sarah X Zhang
- Department of Ophthalmology and Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY, United States; Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY, United States.
| | - Josh J Wang
- Department of Ophthalmology and Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY, United States
| | - Christopher R Starr
- Department of Optometry and Vision Science, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Eun-Jin Lee
- Department of Ophthalmology and Byers Eye Institute, Stanford University, Stanford, CA, United States; VA Palo Alto Healthcare System, Palo Alto, CA, United States; Department of Pathology, Stanford University, Stanford, CA, United States
| | - Karen Sophia Park
- Department of Ophthalmology and Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY, United States
| | - Assylbek Zhylkibayev
- Department of Optometry and Vision Science, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Andy Medina
- Department of Ophthalmology and Ross Eye Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, NY, United States
| | - Jonathan H Lin
- Department of Ophthalmology and Byers Eye Institute, Stanford University, Stanford, CA, United States; VA Palo Alto Healthcare System, Palo Alto, CA, United States; Department of Pathology, Stanford University, Stanford, CA, United States
| | - Marina Gorbatyuk
- Department of Optometry and Vision Science, University of Alabama at Birmingham, Birmingham, AL, United States
| |
Collapse
|
2
|
Ottens F, Efstathiou S, Hoppe T. Cutting through the stress: RNA decay pathways at the endoplasmic reticulum. Trends Cell Biol 2023:S0962-8924(23)00236-2. [PMID: 38008608 DOI: 10.1016/j.tcb.2023.11.003] [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: 09/28/2023] [Revised: 11/07/2023] [Accepted: 11/08/2023] [Indexed: 11/28/2023]
Abstract
The endoplasmic reticulum (ER) is central to the processing of luminal, transmembrane, and secretory proteins, and maintaining a functional ER is essential for organismal physiology and health. Increased protein-folding load on the ER causes ER stress, which activates quality control mechanisms to restore ER function and protein homeostasis. Beyond protein quality control, mRNA decay pathways have emerged as potent ER fidelity regulators, but their mechanistic roles in ER quality control and their interrelationships remain incompletely understood. Herein, we review ER-associated RNA decay pathways - including regulated inositol-requiring enzyme 1α (IRE1α)-dependent mRNA decay (RIDD), nonsense-mediated mRNA decay (NMD), and Argonaute-dependent RNA silencing - in ER homeostasis, and highlight the intricate coordination of ER-targeted RNA and protein decay mechanisms and their association with antiviral defense.
Collapse
Affiliation(s)
- Franziska Ottens
- Institute for Genetics, University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Sotirios Efstathiou
- Institute for Genetics, University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Thorsten Hoppe
- Institute for Genetics, University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany; Center for Molecular Medicine Cologne (CMMC), Faculty of Medicine and University Hospital of Cologne, Cologne, Germany.
| |
Collapse
|
3
|
Lv W, Zheng Y, Jiao J, Fu Y, Xu T, Zhang L, Zhang Z, Ma N. The Role of XBP1 in bone metabolism. Front Endocrinol (Lausanne) 2023; 14:1217579. [PMID: 37795354 PMCID: PMC10546391 DOI: 10.3389/fendo.2023.1217579] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 09/04/2023] [Indexed: 10/06/2023] Open
Abstract
Bone is a dynamic organ that, once formed, undergoes a constant remodeling process that includes bone resorption and synthesis. Osteoclasts and osteoblasts are primarily responsible for controlling this process. X-box binding protein 1 (XBP1), a transcription factor, affects the metabolism of bones in various ways. In recent years, numerous studies have revealed that XBP1 plays a vital role in bone metabolism, including osteoclast and osteoblast development, as well as in regulating immune cell differentiation that affects the immune microenvironment of bone remodeling. In this review, we highlight the regulatory mechanisms of XBP1 on osteoclasts and osteoblasts, how XBP1 affects the immune microenvironment of bone remodeling by influencing the differentiation of immune cells, and predict the possible future research directions of XBP1 to provide new insights for the treatment of bone-related metabolic diseases.
Collapse
Affiliation(s)
- Wenhao Lv
- Hospital of Stomatology, Jilin University, Changchun, China
| | - Youli Zheng
- The School and Hospital of Stomatology, Tianjin Medical University, Tianjin, China
| | - Junjun Jiao
- Hospital of Stomatology, Jilin University, Changchun, China
| | - Yu Fu
- Hospital of Stomatology, Jilin University, Changchun, China
| | - Tingrui Xu
- Hospital of Stomatology, Jilin University, Changchun, China
| | - Li Zhang
- Hospital of Stomatology, Jilin University, Changchun, China
| | - Zheng Zhang
- Tianjin Stomatological Hospital, School of Medicine, Nankai University, Tianjin, China
- Tianjin Key Laboratory of Oral and Maxillofacial Function Reconstruction, Tianjin, China
| | - Ning Ma
- Hospital of Stomatology, Jilin University, Changchun, China
| |
Collapse
|
4
|
Mingjie Y, Yair A, Tali G. The RIDD activity of C. elegans IRE1 modifies neuroendocrine signaling in anticipation of environment stress to ensure survival. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.10.552841. [PMID: 37609168 PMCID: PMC10441387 DOI: 10.1101/2023.08.10.552841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Xbp1 splicing and regulated IRE1-dependent RNA decay (RIDD) are two RNase activities of the ER stress sensor IRE1. While Xbp1 splicing has important roles in stress responses and animal physiology, the physiological role(s) of RIDD remain enigmatic. Genetic evidence in C. elegans connects XBP1-independent IRE1 activity to organismal stress adaptation, but whether this is via RIDD, and what are the targets is yet unknown. We show that cytosolic kinase/RNase domain of C. elegans IRE1 is indeed capable of RIDD in human cells, and that sensory neurons use RIDD to signal environmental stress, by degrading mRNA of TGFβ-like growth factor DAF-7. daf-7 was degraded in human cells by both human and worm IRE1 RNAse activity with same efficiency and specificity as Blos1, confirming daf-7 as RIDD substrate. Surprisingly, daf-7 degradation in vivo was triggered by concentrations of ER stressor tunicamycin too low for xbp-1 splicing. Decrease in DAF-7 normally signals food limitation and harsh environment, triggering adaptive changes to promote population survival. Because C. elegans is a bacteriovore, and tunicamycin, like other common ER stressors, is an antibiotic secreted by Streptomyces spp., we asked whether daf-7 degradation by RIDD could signal pending food deprivation. Indeed, pre-emptive tunicamycin exposure increased survival of C. elegans populations under food limiting/high temperature stress, and this protection was abrogated by overexpression of DAF-7. Thus, C. elegans uses stress-inducing metabolites in its environment as danger signals, and employs IRE1's RIDD activity to modulate the neuroendocrine signaling for survival of upcoming environmental challenge.
Collapse
Affiliation(s)
- Ying Mingjie
- Department of Biology, Drexel University, Philadelphia, PA
- Department of Pathology and Lab Medicine, The Children's Hospital of Philadelphia and the University of Pennsylvania, Philadelphia, PA, USA
| | - Argon Yair
- Department of Pathology and Lab Medicine, The Children's Hospital of Philadelphia and the University of Pennsylvania, Philadelphia, PA, USA
| | | |
Collapse
|
5
|
Celik C, Lee SYT, Yap WS, Thibault G. Endoplasmic reticulum stress and lipids in health and diseases. Prog Lipid Res 2023; 89:101198. [PMID: 36379317 DOI: 10.1016/j.plipres.2022.101198] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 11/03/2022] [Accepted: 11/09/2022] [Indexed: 11/14/2022]
Abstract
The endoplasmic reticulum (ER) is a complex and dynamic organelle that regulates many cellular pathways, including protein synthesis, protein quality control, and lipid synthesis. When one or multiple ER roles are dysregulated and saturated, the ER enters a stress state, which, in turn, activates the highly conserved unfolded protein response (UPR). By sensing the accumulation of unfolded proteins or lipid bilayer stress (LBS) at the ER, the UPR triggers pathways to restore ER homeostasis and eventually induces apoptosis if the stress remains unresolved. In recent years, it has emerged that the UPR works intimately with other cellular pathways to maintain lipid homeostasis at the ER, and so does at cellular levels. Lipid distribution, along with lipid anabolism and catabolism, are tightly regulated, in part, by the ER. Dysfunctional and overwhelmed lipid-related pathways, independently or in combination with ER stress, can have reciprocal effects on other cellular functions, contributing to the development of diseases. In this review, we summarize the current understanding of the UPR in response to proteotoxic stress and LBS and the breadth of the functions mitigated by the UPR in different tissues and in the context of diseases.
Collapse
Affiliation(s)
- Cenk Celik
- School of Biological Sciences, Nanyang Technological University, Singapore
| | | | - Wei Sheng Yap
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Guillaume Thibault
- School of Biological Sciences, Nanyang Technological University, Singapore; Mechanobiology Institute, National University of Singapore, Singapore; Institute of Molecular and Cell Biology, A*STAR, Singapore.
| |
Collapse
|