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Skerjanz J, Bauernhofer L, Lenk K, Emmerstorfer-Augustin A, Leitinger G, Reichmann F, Stockner T, Groschner K, Tiapko O. TRPC1: The housekeeper of the hippocampus. Cell Calcium 2024; 123:102933. [PMID: 39116710 DOI: 10.1016/j.ceca.2024.102933] [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: 06/19/2024] [Revised: 07/25/2024] [Accepted: 07/26/2024] [Indexed: 08/10/2024]
Abstract
The non-selective cation channel TRPC1 is highly expressed in the brain. Recent research shows that neuronal TRPC1 forms heteromeric complexes with TRPC4 and TRPC5, with a small portion existing as homotetramers, primarily in the ER. Given that most studies have focused on the role of heteromeric TRPC1/4/5 complexes, it is crucial to investigate the specific role of homomeric TRPC1 in maintaining brain homeostasis. This review highlights recent findings on TRPC1 in the brain, with a focus on the hippocampus, and compiles the latest data on modulators and their binding sites within the TRPC1/4/5 subfamily to stimulate new research on more selective TRPC1 ligands.
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Affiliation(s)
- Julia Skerjanz
- Gottfried Schatz Research Center, Division of Medical Physics and Biophysics, Medical University of Graz, Austria
| | - Lena Bauernhofer
- Biophysics Division, Institute of Molecular Biosciences, NAWI Graz, University of Graz, Austria; BioTechMed-Graz, Austria
| | - Kerstin Lenk
- Institute of Neural Engineering, Graz University of Technology, Austria; BioTechMed-Graz, Austria
| | | | - Gerd Leitinger
- Gottfried Schatz Research Center, Division of Cell Biology, Histology and Embryology, Medical University of Graz, Austria; BioTechMed-Graz, Austria; MEFOgraz, Austria
| | - Florian Reichmann
- Otto Loewi Research Center, Division of Pharmacology, Medical University of Graz, Austria; BioTechMed-Graz, Austria
| | - Thomas Stockner
- Department of Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Klaus Groschner
- Gottfried Schatz Research Center, Division of Medical Physics and Biophysics, Medical University of Graz, Austria
| | - Oleksandra Tiapko
- Gottfried Schatz Research Center, Division of Medical Physics and Biophysics, Medical University of Graz, Austria; BioTechMed-Graz, Austria; MEFOgraz, Austria.
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2
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Zhou C, Yang MJ, Hu Z, Zou Y, Shi P, Li YR, Guo YJ, Song H, Zhang T. Autophagy contributes to increase the content of intracellular free amino acids in hard clam (Mercenaria mercenaria) during prolonged exposure to hypersaline environments. MARINE ENVIRONMENTAL RESEARCH 2023; 192:106198. [PMID: 37757610 DOI: 10.1016/j.marenvres.2023.106198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 09/16/2023] [Accepted: 09/21/2023] [Indexed: 09/29/2023]
Abstract
Marine bivalves in intertidal zones and land-based seawater ponds are constantly subjected to a wide range of salinity fluctuations due to heavy rainfall, intense drought, and human activities. As osmoconformers, bivalves rely primarily on rapid release or accumulation of free amino acids (FAAs) for osmoregulation. Euryhaline bivalves are capable of withstanding hyposaline and hypersaline environments through regulation of physiology, metabolism, and gene expression. However, current understanding of the molecular mechanisms underlying osmoregulation and salinity adaptation in euryhaline bivalves remains largely limited. In this study, RNA-seq, WGCNA and flow cytometric analysis were performed to investigate the physiological responses of hard clams (Mercenaria mercenaria) to acute short-term hyposalinity (AL) and hypersalinity (AH), and chronic long-term hyposalinity (CL) and hypersalinity (CH) stress. We found that amino acids biosynthesis was significantly inhibited and aminoacyl-tRNA biosynthesis was augmented to decrease intracellular osmolarity during hyposaline exposure. Under CH, numerous autophagy-related genes (ATGs) were highly expressed, and the autophagy activity of gill cells were significantly up-regulated. A significant decrease in total FAAs content was observed in gills after NH4Cl treatment, indicating that autophagy was crucial for osmoregulation in hard clams during prolonged exposure to hypersaline environments. To prevent premature or unnecessary apoptosis, the expression of cathepsin L was inhibited under AL and AH, and inhibitors of apoptosis was augmented under CL and CH. Additionally, neuroendocrine regulation was involved in salinity adaption in hard clams. This study provides novel insights into the physiological responses of euryhaline marine bivalves to hyposaline and hypersaline environments.
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Affiliation(s)
- Cong Zhou
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266071, China; CAS Engineering Laboratory for Marine Ranching, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Shandong Province Key Laboratory of Experimental Marine Biology, Qingdao, 266071, China
| | - Mei-Jie Yang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266071, China; CAS Engineering Laboratory for Marine Ranching, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Shandong Province Key Laboratory of Experimental Marine Biology, Qingdao, 266071, China
| | - Zhi Hu
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266071, China; CAS Engineering Laboratory for Marine Ranching, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Shandong Province Key Laboratory of Experimental Marine Biology, Qingdao, 266071, China
| | - Yan Zou
- Marine Science Research Institute of Shandong Province, Qingdao, 266100, China
| | - Pu Shi
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266071, China; CAS Engineering Laboratory for Marine Ranching, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Shandong Province Key Laboratory of Experimental Marine Biology, Qingdao, 266071, China
| | - Yong-Ren Li
- Tianjin Key Laboratory of Aqua-ecology and Aquaculture, Fisheries College, Tianjin Agricultural University, Tianjin, 300384, China
| | - Yong-Jun Guo
- Tianjin Key Laboratory of Aqua-ecology and Aquaculture, Fisheries College, Tianjin Agricultural University, Tianjin, 300384, China
| | - Hao Song
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266071, China; CAS Engineering Laboratory for Marine Ranching, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China; Shandong Province Key Laboratory of Experimental Marine Biology, Qingdao, 266071, China.
| | - Tao Zhang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266071, China; CAS Engineering Laboratory for Marine Ranching, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China; Shandong Province Key Laboratory of Experimental Marine Biology, Qingdao, 266071, China.
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3
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Passos E, Pereira C, Gonçalves IO, Faria A, Ascensão A, Monteiro R, Magalhães J, Martins MJ. Physical exercise positively modulates nonalcoholic steatohepatitis-related hepatic endoplasmic reticulum stress. J Cell Biochem 2022; 123:1647-1662. [PMID: 35467032 DOI: 10.1002/jcb.30250] [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: 11/17/2021] [Revised: 03/17/2022] [Accepted: 03/29/2022] [Indexed: 11/09/2022]
Abstract
Obesity is a predictive factor for the development of nonalcoholic steatohepatitis (NASH). Although some of the mechanisms associated with NASH development are still elusive, its pathogenesis relies on a complex broad spectrum of (interconnected) metabolic-based disorders. We analyzed the effects of voluntary physical activity (VPA) and endurance training (ET), as preventive and therapeutic nonpharmacological strategies, respectively, against hepatic endoplasmic reticulum (ER) stress, ER-related proapoptotic signaling, and oxidative stress in an animal model of high-fat diet (HFD)-induced NASH. Adult male Sprague-Dawley rats were divided into standard control liquid diet (SCLD) or HFD groups, with sedentary, VPA, and ET subgroups in both (sedentary animals with access to SCLD [SS], voluntarily physically active animals with access to SCLD [SV], and endurance-trained animals with access to SCLD [ST] in the former and sedentary animals with access to liquid HFD [HS], voluntarily physically active animals with access to liquid HFD [HV], and endurance-trained animals with access to liquid HFD [HT] in the latter, respectively). Hepatic ER stress and ER-related proapoptotic signaling were evaluated by Western blot and reverse transcriptase-polymerase chain reaction; redox status was evaluated through quantification of lipid peroxidation, protein carbonyls groups, and glutathione levels as well as antioxidant enzymes activity. In SCLD-treated animals, VPA significantly decreased eukaryotic initiation factor-2 alpha (eIF2α). In HFD-treated animals, VPA significantly decreased eIF2α and phospho-inositol requiring enzyme-1 alpha (IRE1α) but ET significantly decreased eIF2α and significantly increased both spliced X-box binding protein 1 (sXBP1) and unspliced X-box binding protein 1; a significant increase of phosphorylated-eIF2α (p-eIF2α) to eIF2α ratio occurred in ET versus VPA. HS compared to SS disclosed a significant increase of total and reduced glutathione, HV compared to SV a significant increase of oxidized glutathione, HT compared to ST a significant increase of p-eIF2α to eIF2α ratio and sXBP1. Physical exercise counteracts NASH-related ER stress and its associated deleterious consequences through a positive and dynamical modulation of the hepatic IRE1α-X-box binding protein 1 pathway.
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Affiliation(s)
- Emanuel Passos
- Department of Biomedicine, Unit of Biochemistry, Faculty of Medicine, University of Porto, Porto, Portugal.,National Anti-Doping Organization of Cape Verde, Praia, Cabo Verde.,Laboratory for Integrative and Translational Research in Population Health (ITR), Laboratory of Metabolism and Exercise (LaMetEx), Research Centre in Physical Activity, Health and Leisure (CIAFEL), Faculty of Sport, University of Porto, Porto, Portugal
| | - Cidália Pereira
- School of Health Sciences, Polytechnic of Leiria, Leiria, Portugal.,CiTechCare-Centre for Innovative Care and Health Technology, Polytechnic of Leiria, Leiria, Portugal
| | - Inês O Gonçalves
- Laboratory for Integrative and Translational Research in Population Health (ITR), Laboratory of Metabolism and Exercise (LaMetEx), Research Centre in Physical Activity, Health and Leisure (CIAFEL), Faculty of Sport, University of Porto, Porto, Portugal
| | - Ana Faria
- Nutrition and Metabolism, Faculdade de Ciências Médicas, NOVA Medical School, Universidade NOVA de Lisboa, Lisboa, Portugal.,CINTESIS-Center for Health Technology Services Research, Faculty of Medicine, University of Porto, Porto, Portugal.,Comprehensive Health Research Centre, Universidade NOVA de Lisboa, Lisboa, Portugal
| | - António Ascensão
- Laboratory for Integrative and Translational Research in Population Health (ITR), Laboratory of Metabolism and Exercise (LaMetEx), Research Centre in Physical Activity, Health and Leisure (CIAFEL), Faculty of Sport, University of Porto, Porto, Portugal
| | - Rosário Monteiro
- CINTESIS-Center for Health Technology Services Research, Faculty of Medicine, University of Porto, Porto, Portugal.,Unidade de Saúde Familiar Homem do Leme, Agrupamento de Centros de Saúde Porto Ocidental, ARS Norte, Porto, Portugal.,MEDCIDS-Department of Community Medicine, Information and Health Decision Sciences, Faculty of Medicine, University of Porto, Porto, Portugal
| | - José Magalhães
- Laboratory for Integrative and Translational Research in Population Health (ITR), Laboratory of Metabolism and Exercise (LaMetEx), Research Centre in Physical Activity, Health and Leisure (CIAFEL), Faculty of Sport, University of Porto, Porto, Portugal
| | - Maria J Martins
- Department of Biomedicine, Unit of Biochemistry, Faculty of Medicine, University of Porto, Porto, Portugal.,Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal
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4
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Gao H, He C, Hua R, Guo Y, Wang B, Liang C, Gao L, Shang H, Xu JD. Endoplasmic Reticulum Stress of Gut Enterocyte and Intestinal Diseases. Front Mol Biosci 2022; 9:817392. [PMID: 35402506 PMCID: PMC8988245 DOI: 10.3389/fmolb.2022.817392] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 01/19/2022] [Indexed: 12/21/2022] Open
Abstract
The endoplasmic reticulum, a vast reticular membranous network from the nuclear envelope to the plasma membrane responsible for the synthesis, maturation, and trafficking of a wide range of proteins, is considerably sensitive to changes in its luminal homeostasis. The loss of ER luminal homeostasis leads to abnormalities referred to as endoplasmic reticulum (ER) stress. Thus, the cell activates an adaptive response known as the unfolded protein response (UPR), a mechanism to stabilize ER homeostasis under severe environmental conditions. ER stress has recently been postulated as a disease research breakthrough due to its significant role in multiple vital cellular functions. This has caused numerous reports that ER stress-induced cell dysfunction has been implicated as an essential contributor to the occurrence and development of many diseases, resulting in them targeting the relief of ER stress. This review aims to outline the multiple molecular mechanisms of ER stress that can elucidate ER as an expansive, membrane-enclosed organelle playing a crucial role in numerous cellular functions with evident changes of several cells encountering ER stress. Alongside, we mainly focused on the therapeutic potential of ER stress inhibition in gastrointestinal diseases such as inflammatory bowel disease (IBD) and colorectal cancer. To conclude, we reviewed advanced research and highlighted future treatment strategies of ER stress-associated conditions.
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Affiliation(s)
- Han Gao
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Chengwei He
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Rongxuan Hua
- Department of Clinical Medicine, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Yuexin Guo
- Department of Oral Medicine, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Boya Wang
- Undergraduate Student of 2018 Eight Program of Clinical Medicine, Peking University Health Science Center, Beijing, China
| | - Chen Liang
- Department of Clinical Medicine, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Lei Gao
- Department of Biomedical Informatics, School of Biomedical Engineering, Capital Medical University, Beijing, China
| | - Hongwei Shang
- Experimental Center for Morphological Research Platform, Capital Medical University, Beijing, China
| | - Jing-Dong Xu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
- *Correspondence: Jing-Dong Xu,
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5
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Thakur AK, Luthra-Guptasarma M. Differences in Cellular Clearing Mechanisms of Aggregates of Two Subtypes of HLA-B27. Front Immunol 2022; 12:795053. [PMID: 35082784 PMCID: PMC8785436 DOI: 10.3389/fimmu.2021.795053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 12/10/2021] [Indexed: 01/08/2023] Open
Abstract
Ankylosing spondylitis (AS) belongs to a group of diseases, called spondyloarthropathies (SpA), that are strongly associated with the genetic marker HLA-B27. AS is characterized by inflammation of joints and primarily affects the spine. Over 160 subtypes of HLA-B27 are known, owing to high polymorphism. Some are strongly associated with disease (e.g., B*2704), whereas others are not (e.g., B*2709). Misfolding of HLA-B27 molecules [as dimers, or as high-molecular-weight (HMW) oligomers] is one of several hypotheses proposed to explain the link between HLA-B27 and AS. Our group has previously established the existence of HMW species of HLA-B27 in AS patients. Still, very little is known about the mechanisms underlying differences in pathogenic outcomes of different HLA-B27 subtypes. We conducted a proteomics-based evaluation of the differential disease association of HLA B*2704 and B*2709, using stable transfectants of genes encoding the two proteins. A clear difference was observed in protein clearance mechanisms: whereas unfolded protein response (UPR), autophagy, and aggresomes were involved in the degradation of B*2704, the endosome–lysosome machinery was primarily involved in B*2709 degradation. These differences offer insights into the differential disease association of B*2704 and B*2709.
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Affiliation(s)
- Amit Kumar Thakur
- Department of Immunopathology, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Manni Luthra-Guptasarma
- Department of Immunopathology, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
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6
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Singh R, Kaur N, Dhingra N, Kaur T. Protein misfolding, ER Stress and Chaperones: An approach to develop chaperone-based therapeutics for Alzheimer's Disease. Int J Neurosci 2021:1-21. [PMID: 34402740 DOI: 10.1080/00207454.2021.1968859] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Alzheimer's disease (AD) is a heterogeneous neurodegenerative disorder with complex etiology that eventually leads to dementia. The main culprit of AD is the extracellular deposition of β-amyloid (Aβ) and intracellular neurofibrillary tangles. The protein conformational change and protein misfolding are the key events of AD pathophysiology, therefore endoplasmic reticulum (ER) stress is an apparent consequence. ER, stress-induced unfolded protein response (UPR) mediators (viz. PERK, IRE1, and ATF6) have been reported widely in the AD brain. Considering these factors, preventing proteins misfolding or aggregation of tau or amyloidogenic proteins appears to be the best approach to halt its pathogenesis. Therefore, therapies through chemical and pharmacological chaperones came to light as an alternative for the treatment of AD. Diverse studies have demonstrated 4-phenylbutyric acid (4-PBA) as a potential therapeutic agent in AD. The current review outlined the mechanism of protein misfolding, different etiological features behind the progression of AD, the significance of ER stress in AD, and the potential therapeutic role of different chaperones to counter AD. The study also highlights the gaps in current knowledge of the chaperones-based therapeutic approach and the possibility of developing chaperones as a potential therapeutic agent for AD treatment.
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Affiliation(s)
- Rimaljot Singh
- Department of Biophysics, Panjab University Chandigarh, India
| | - Navpreet Kaur
- Department of Biophysics, Panjab University Chandigarh, India
| | - Neelima Dhingra
- University Institute of Pharmaceutical Sciences, Panjab University Chandigarh, India
| | - Tanzeer Kaur
- Department of Biophysics, Panjab University Chandigarh, India
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7
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Zhou C, Song H, Feng J, Hu Z, Yu ZL, Yang MJ, Shi P, Li YR, Guo YJ, Zhang T. RNA-Seq analysis and WGCNA reveal dynamic molecular responses to air exposure in the hard clam Mercenaria mercenaria. Genomics 2021; 113:2847-2859. [PMID: 34153497 DOI: 10.1016/j.ygeno.2021.06.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 06/14/2021] [Accepted: 06/16/2021] [Indexed: 12/12/2022]
Abstract
Intertidal bivalves are constantly exposed to air due to daily and seasonal tidal cycles. The hard clam Mercenaria mercenaria is an economically important bivalve species and often subjected to air exposure for more than 10 days during long-distance transportation. Hard clam exhibits remarkable tolerance to air exposure. In this study, we performed RNA sequencing on hemocytes of M. mercenaria exposed to air for 0, 1, 5, 10, 20 and 30 days. The overall and dynamic molecular responses of hard clams to air exposure were revealed by different transcriptomic analysis strategies. As a result, most cytochrome P450 1A and 3A, and monocarboxylate transporter family members were up-regulated during air exposure. Additionally, the dominant molecular process in response to 5-d, 10-d, 20-d and 30-d air exposure was refolding of misfolded proteins in endoplasmic reticulum, lysosome-mediated degradation of phospholipids, protein metabolism and reorganization of cytoskeleton, and activation of anti-apoptotic process, respectively. Our results facilitated comprehensive understanding of the tolerance mechanisms of intertidal bivalves to air exposure.
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Affiliation(s)
- Cong Zhou
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; CAS Engineering Laboratory for Marine Ranching, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China; Shandong Province Key Laboratory of Experimental Marine Biology, Qingdao 266071, China
| | - Hao Song
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China; CAS Engineering Laboratory for Marine Ranching, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Shandong Province Key Laboratory of Experimental Marine Biology, Qingdao 266071, China
| | - Jie Feng
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; CAS Engineering Laboratory for Marine Ranching, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Shandong Province Key Laboratory of Experimental Marine Biology, Qingdao 266071, China
| | - Zhi Hu
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; CAS Engineering Laboratory for Marine Ranching, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China; Shandong Province Key Laboratory of Experimental Marine Biology, Qingdao 266071, China
| | - Zheng-Lin Yu
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; CAS Engineering Laboratory for Marine Ranching, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China; Shandong Province Key Laboratory of Experimental Marine Biology, Qingdao 266071, China
| | - Mei-Jie Yang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; CAS Engineering Laboratory for Marine Ranching, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China; Shandong Province Key Laboratory of Experimental Marine Biology, Qingdao 266071, China
| | - Pu Shi
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; CAS Engineering Laboratory for Marine Ranching, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; University of Chinese Academy of Sciences, Beijing 100049, China; Shandong Province Key Laboratory of Experimental Marine Biology, Qingdao 266071, China
| | - Yong-Ren Li
- Tianjin Key Laboratory of Aqua-ecology and Aquaculture, Fisheries College, Tianjin Agricultural University, Tianjin 300384, China
| | - Yong-Jun Guo
- Tianjin Key Laboratory of Aqua-ecology and Aquaculture, Fisheries College, Tianjin Agricultural University, Tianjin 300384, China
| | - Tao Zhang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China; CAS Engineering Laboratory for Marine Ranching, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Shandong Province Key Laboratory of Experimental Marine Biology, Qingdao 266071, China.
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8
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The Role of Molecular Chaperones in Virus Infection and Implications for Understanding and Treating COVID-19. J Clin Med 2020; 9:jcm9113518. [PMID: 33143379 PMCID: PMC7693988 DOI: 10.3390/jcm9113518] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/24/2020] [Accepted: 10/28/2020] [Indexed: 12/14/2022] Open
Abstract
The COVID-19 pandemic made imperative the search for means to end it, which requires a knowledge of the mechanisms underpinning the multiplication and spread of its cause, the coronavirus SARS-CoV-2. Many viruses use members of the hosts’ chaperoning system to infect the target cells, replicate, and spread, and here we present illustrative examples. Unfortunately, the role of chaperones in the SARS-CoV-2 cycle is still poorly understood. In this review, we examine the interactions of various coronaviruses during their infectious cycle with chaperones in search of information useful for future research on SARS-CoV-2. We also call attention to the possible role of molecular mimicry in the development of autoimmunity and its widespread pathogenic impact in COVID-19 patients. Viral proteins share highly antigenic epitopes with human chaperones, eliciting anti-viral antibodies that crossreact with the chaperones. Both, the critical functions of chaperones in the infectious cycle of viruses and the possible role of these molecules in COVID-19 autoimmune phenomena, make clear that molecular chaperones are promising candidates for the development of antiviral strategies. These could consist of inhibiting-blocking those chaperones that are necessary for the infectious viral cycle, or those that act as autoantigens in the autoimmune reactions causing generalized destructive effects on human tissues.
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Wu Chuang A, Kepp O, Kroemer G, Bezu L. Endoplasmic reticulum stress in the cellular release of damage-associated molecular patterns. BIOLOGY OF THE ENDOPLASMIC RETICULUM 2020; 350:1-28. [DOI: 10.1016/bs.ircmb.2019.11.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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10
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Mathias S, Wippermann A, Raab N, Zeh N, Handrick R, Gorr I, Schulz P, Fischer S, Gamer M, Otte K. Unraveling what makes a monoclonal antibody difficult‐to‐express: From intracellular accumulation to incomplete folding and degradation via ERAD. Biotechnol Bioeng 2019; 117:5-16. [DOI: 10.1002/bit.27196] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Revised: 08/13/2019] [Accepted: 10/15/2019] [Indexed: 01/02/2023]
Affiliation(s)
- Sven Mathias
- Institute of Applied BiotechnologyUniversity of Applied Sciences Biberach Biberach Germany
| | - Anna Wippermann
- Cell Line Development, Bioprocess Development BiologicalsBoehringer Ingelheim Pharma GmbH & Co. KG Biberach Germany
| | - Nadja Raab
- Institute of Applied BiotechnologyUniversity of Applied Sciences Biberach Biberach Germany
| | - Nikolas Zeh
- Institute of Applied BiotechnologyUniversity of Applied Sciences Biberach Biberach Germany
| | - René Handrick
- Institute of Applied BiotechnologyUniversity of Applied Sciences Biberach Biberach Germany
| | - Ingo Gorr
- Early Stage Bioprocess Development, Bioprocess Development BiologicalsBoehringer Ingelheim Pharma GmbH & Co. KG Biberach Germany
| | - Patrick Schulz
- Cell Line Development, Bioprocess Development BiologicalsBoehringer Ingelheim Pharma GmbH & Co. KG Biberach Germany
| | - Simon Fischer
- Cell Line Development CMB, Bioprocess & Analytical DevelopmentBoehringer Ingelheim Pharma GmbH & Co. KG Biberach Germany
| | - Martin Gamer
- Cell Line Development, Bioprocess Development BiologicalsBoehringer Ingelheim Pharma GmbH & Co. KG Biberach Germany
| | - Kerstin Otte
- Institute of Applied BiotechnologyUniversity of Applied Sciences Biberach Biberach Germany
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Wang S, Li X, Li T, Wang H, Zhang X, Lou J, Xing Q, Hu X, Bao Z. The GRP94 gene of Yesso scallop (Patinopecten yessoensis): Characterization and expression regulation in response to thermal and bacterial stresses. FISH & SHELLFISH IMMUNOLOGY 2018; 80:443-451. [PMID: 29894740 DOI: 10.1016/j.fsi.2018.06.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 06/09/2018] [Indexed: 06/08/2023]
Abstract
The 94-kDa glucose-regulated protein (GRP94) belonging to the HSP90 family is an endoplasmic reticulum (ER) chaperone. It plays critical roles in ER quality control, and has been implicated as a specialized immune chaperone to regulate both innate and adaptive immunity. In this study, we identified and characterized a GRP94 gene (PyGRP94) from Yesso scallop (Patinopecten yessoensis). The protein sequence of PyGRP94 is highly conserved with its homologs in vertebrates, with a signal sequence in N-terminal, an ER retrieval signal sequence in C-terminal and a HATPase_c domain. Expression analysis suggests that PyGRP94 transcripts in early embryos are maternally derived and the zygotic expression is started from D-shaped larvae. This gene is also expressed in almost all the adult tissues examined except smooth muscle, with the highest expression level in hemocytes. Besides, PyGRP94 was demonstrated to be induced by heat shock and both Gram-positive (Micrococcus luteus) and Gram-negative (Vibrio anguillarum) bacterial infection, with much more dramatic changes being observed after V. anguillarum challenge. Our results suggest the involvement of PyGRP94 in response to thermal stress, and that it might play an important role in the innate immune defense of scallop.
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Affiliation(s)
- Shuyue Wang
- Key Laboratory of Marine Genetics and Breeding (Ocean University of China), Ministry of Education, Qingdao 266003, China
| | - Xu Li
- Key Laboratory of Marine Genetics and Breeding (Ocean University of China), Ministry of Education, Qingdao 266003, China
| | - Tingting Li
- Key Laboratory of Marine Genetics and Breeding (Ocean University of China), Ministry of Education, Qingdao 266003, China
| | - Huizhen Wang
- Key Laboratory of Marine Genetics and Breeding (Ocean University of China), Ministry of Education, Qingdao 266003, China
| | - Xiangchao Zhang
- Key Laboratory of Marine Genetics and Breeding (Ocean University of China), Ministry of Education, Qingdao 266003, China
| | - Jiarun Lou
- Key Laboratory of Marine Genetics and Breeding (Ocean University of China), Ministry of Education, Qingdao 266003, China
| | - Qiang Xing
- Key Laboratory of Marine Genetics and Breeding (Ocean University of China), Ministry of Education, Qingdao 266003, China
| | - Xiaoli Hu
- Key Laboratory of Marine Genetics and Breeding (Ocean University of China), Ministry of Education, Qingdao 266003, China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China.
| | - Zhenmin Bao
- Key Laboratory of Marine Genetics and Breeding (Ocean University of China), Ministry of Education, Qingdao 266003, China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
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12
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Shen K, Johnson DW, Vesey DA, McGuckin MA, Gobe GC. Role of the unfolded protein response in determining the fate of tumor cells and the promise of multi-targeted therapies. Cell Stress Chaperones 2018; 23:317-334. [PMID: 28952072 PMCID: PMC5904077 DOI: 10.1007/s12192-017-0844-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Accepted: 09/13/2017] [Indexed: 02/06/2023] Open
Abstract
Although there have been advances in our understanding of carcinogenesis and development of new treatments, cancer remains a common cause of death. Many regulatory pathways are incompletely understood in cancer development and progression, with a prime example being those related to the endoplasmic reticulum (ER). The pathological sequelae that arise from disruption of ER homeostasis are not well defined. The ER is an organelle that is responsible for secretory protein biosynthesis and the quality control of protein folding. The ER triggers an unfolded protein response (UPR) when misfolded proteins accumulate, and while the UPR acts to restore protein folding and ER homeostasis, this response can work as a switch to determine the death or survival of cells. The treatment of cancer with agents that target the UPR has shown promising outcomes. The UPR has wide crosstalk with other signaling pathways. Multi-targeted cancer therapies which target the intersections within signaling networks have shown synergistic tumoricidal effects. In the present review, the basic cellular and signaling pathways of the ER and UPR are introduced; then the crosstalk between the ER and other signaling pathways is summarized; and ultimately, the evidence that the UPR is a potential target for cancer therapy is discussed. Regulation of the UPR downstream signaling is a common therapeutic target for different tumor types. Tumoricidal effects achieved from modulating the UPR downstream signaling could be enhanced by phosphodiesterase 5 (PDE5) inhibitors. Largely untapped by Western medicine for cancer therapies are Chinese herbal medicines. This review explores and discusses the value of some Chinese herbal extracts as PDE5 inhibitors.
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Affiliation(s)
- Kunyu Shen
- Kidney Disease Research Group, UQ Diamantina Institute, Translational Research Institute, The University of Queensland, 37 Kent Street, Woolloongabba, Brisbane, 4102, Australia
| | - David W Johnson
- Kidney Disease Research Group, UQ Diamantina Institute, Translational Research Institute, The University of Queensland, 37 Kent Street, Woolloongabba, Brisbane, 4102, Australia
- Department of Nephrology, Princess Alexandra Hospital, Woolloongabba, Brisbane, Australia
- Centre for Health Services Research, Faculty of Medicine, The University of Queensland, Brisbane, Australia
| | - David A Vesey
- Department of Nephrology, Princess Alexandra Hospital, Woolloongabba, Brisbane, Australia
- Centre for Health Services Research, Faculty of Medicine, The University of Queensland, Brisbane, Australia
| | - Michael A McGuckin
- Mucosal Disease Inflammatory Disease Biology and Therapeutics Group, UQ Mater Research Institute, Translational Research Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Glenda C Gobe
- Kidney Disease Research Group, UQ Diamantina Institute, Translational Research Institute, The University of Queensland, 37 Kent Street, Woolloongabba, Brisbane, 4102, Australia.
- Centre for Health Services Research, Faculty of Medicine, The University of Queensland, Brisbane, Australia.
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13
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The opposite role of two UBA-UBX containing proteins, p47 and SAKS1 in the degradation of a single ERAD substrate, α-TCR. Mol Cell Biochem 2016; 425:37-45. [PMID: 27785701 DOI: 10.1007/s11010-016-2860-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 10/22/2016] [Indexed: 10/20/2022]
Abstract
The UBA-UBX domain-containing proteins can interact with ubiquitinated substrates and p97 during endoplasmic reticulum-associated degradation (ERAD). Here, we found that the expressions of all UBA-UBX genes p47, SAKS1, UBXD8, FAF1, and UBXD7 were elevated upon ER stress, albeit with different levels. Of which p47, SAKS1, and UBXD8 are 'immediate' respondents whereas FAF1 and UBXD7 were 'late' respondents to ER stress. Interestingly, the expression of specific UBA-UBX genes were altered in cells stably expressing three different ERAD substrates such as α-TCR, α1-antitrypsin, and δCD3. We first found that p47 and UBXD8 expression levels were increased in α-TCR and α1-antitrypsin stable cell lines, respectively, whereas SAKS1 expression level was reduced in all the three ERAD substrates tested. Of note, we also found p47 promotes, whereas SASK1 delays the degradation of a single ERAD substrate, α-TCR. Additionally, we found that SAKS1 selectively inhibits the degradation of ERAD substrates without affecting cytosolic proteasomal substrates. Taken together, our results identified that UBA-UBX proteins possess substrate selectivity and opposite role of two different UBA-UBX proteins in the degradation of a single ERAD substrate.
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Chen M, Li X, Zhu A, Storey KB, Sun L, Gao T, Wang T. Understanding mechanism of sea cucumber Apostichopus japonicus aestivation: Insights from TMT-based proteomic study. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2016; 19:78-89. [DOI: 10.1016/j.cbd.2016.06.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 05/31/2016] [Accepted: 06/14/2016] [Indexed: 12/16/2022]
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15
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Dangi A, Huang C, Tandon A, Stolz D, Wu T, Gandhi CR. Endotoxin-stimulated Rat Hepatic Stellate Cells Induce Autophagy in Hepatocytes as a Survival Mechanism. J Cell Physiol 2016; 231:94-105. [PMID: 26031389 DOI: 10.1002/jcp.25055] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 05/26/2015] [Indexed: 12/15/2022]
Abstract
Bacterial lipopolysaccharide (LPS)-stimulated hepatic stellate cells (HSCs) produce many cytokines including IFNβ, TNFα, and IL6, strongly inhibit DNA synthesis, but induce apoptosis of a small number of hepatocytes. In vivo administration of LPS (up to 10 mg/mL) causes modest inflammation and weight loss in rats but not mortality. We determined whether LPS-stimulated HSCs instigate mechanisms of hepatocyte survival. Rats received 10 mg/kg LPS (i.p.) and determinations were made at 6 h. In vitro, HSCs were treated with 100 ng/mL LPS till 24 h. The medium was transferred to hepatocytes, and determinations were made at 0-12 h. Controls were HSC-conditioned medium or medium-containing LPS. LPS treatment of rats caused autophagy in hepatocytes, a physiological process for clearance of undesirable material including injured or damaged organelles. This was accompanied by activation of c-Jun NH2 terminal kinase (JNK) and apoptosis of ~4-5% of hepatocytes. In vitro, LPS-conditioned HSC medium (LPS/HSC) induced autophagy in hepatocytes but apoptosis of only ~10% of hepatocytes. While LPS/HSC stimulated activation of JNK (associated with cell death), it also activated NFkB and ERK1/2 (associated with cell survival). LPS-stimulated HSCs produced IFNβ, and LPS/HSC-induced autophagy in hepatocytes and their apoptosis were significantly inhibited by anti-IFNβ antibody. Blockade of autophagy, on the other hand, strongly augmented hepatocyte apoptosis. While LPS-stimulated HSCs cause apoptosis of a subpopulation of hepatocytes by producing IFNβ, they also induce cell survival mechanisms, which may be of critical importance in resistance to liver injury during endotoxemia.
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Affiliation(s)
- Anil Dangi
- Thomas E. Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania.,Department of Surgery, University of Cincinnati, and Cincinnati VA Medical Center, Cincinnati, Ohio.,Cincinnati VA Medical Center, Cincinnati, Ohio
| | - Chao Huang
- Thomas E. Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Ashish Tandon
- Thomas E. Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania.,Department of Surgery, University of Cincinnati, and Cincinnati VA Medical Center, Cincinnati, Ohio
| | - Donna Stolz
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Tong Wu
- Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, Louisiana
| | - Chandrashekhar R Gandhi
- Thomas E. Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania.,Department of Surgery, University of Cincinnati, and Cincinnati VA Medical Center, Cincinnati, Ohio.,Cincinnati VA Medical Center, Cincinnati, Ohio.,Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
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16
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Kepp O, Menger L, Vacchelli E, Locher C, Adjemian S, Yamazaki T, Martins I, Sukkurwala AQ, Michaud M, Senovilla L, Galluzzi L, Kroemer G, Zitvogel L. Crosstalk between ER stress and immunogenic cell death. Cytokine Growth Factor Rev 2013; 24:311-8. [DOI: 10.1016/j.cytogfr.2013.05.001] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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17
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Atkins C, Liu Q, Minthorn E, Zhang SY, Figueroa DJ, Moss K, Stanley TB, Sanders B, Goetz A, Gaul N, Choudhry AE, Alsaid H, Jucker BM, Axten JM, Kumar R. Characterization of a novel PERK kinase inhibitor with antitumor and antiangiogenic activity. Cancer Res 2013; 73:1993-2002. [PMID: 23333938 DOI: 10.1158/0008-5472.can-12-3109] [Citation(s) in RCA: 348] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The unfolded protein response (UPR) is a signal transduction pathway that coordinates cellular adaptation to microenvironmental stresses that include hypoxia, nutrient deprivation, and change in redox status. These stress stimuli are common in many tumors and thus targeting components of the UPR signaling is an attractive therapeutic approach. We have identified a first-in-class, small molecule inhibitor of the eukaryotic initiation factor 2-alpha kinase 3 (EIF2AK3) or PERK, one of the three mediators of UPR signaling. GSK2656157 is an ATP-competitive inhibitor of PERK enzyme activity with an IC(50) of 0.9 nmol/L. It is highly selective for PERK with IC(50) values >100 nmol/L against a panel of 300 kinases. GSK2656157 inhibits PERK activity in cells with an IC(50) in the range of 10-30 nmol/L as shown by inhibition of stress-induced PERK autophosphorylation, eIF2α substrate phosphorylation, together with corresponding decreases in ATF4 and CAAT/enhancer binding protein homologous protein (CHOP) in multiple cell lines. Oral administration of GSK2656157 to mice shows a dose- and time-dependent pharmacodynamic response in pancreas as measured by PERK autophosphorylation. Twice daily dosing of GSK2656157 results in dose-dependent inhibition of multiple human tumor xenografts growth in mice. Altered amino acid metabolism, decreased blood vessel density, and vascular perfusion are potential mechanisms for the observed antitumor effect. However, despite its antitumor activity, given the on-target pharmacologic effects of PERK inhibition on pancreatic function, development of any PERK inhibitor in human subjects would need to be cautiously pursued in cancer patients.
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Affiliation(s)
- Charity Atkins
- GlaxoSmithKline, Oncology R&D, Collegeville, Pennsylvania 19426, USA
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Martinon F. The endoplasmic reticulum: a sensor of cellular stress that modulates immune responses. Microbes Infect 2012; 14:1293-300. [PMID: 22800981 PMCID: PMC7110899 DOI: 10.1016/j.micinf.2012.07.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Revised: 07/03/2012] [Accepted: 07/04/2012] [Indexed: 12/25/2022]
Abstract
Many inflammatory and infectious diseases are characterized by the activation of signaling pathways steaming from the endoplasmic reticulum (ER). These pathways, primarily associated with loss of ER homeostasis, are emerging as key regulators of inflammation and infection. Recent advances shed light on the mechanisms linking ER-stress and immune responses.
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Affiliation(s)
- Fabio Martinon
- Dept. of Biochemistry, University of Lausanne, 155 Ch. Des Boveresses, Epalinges 1066, Switzerland.
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19
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Abstract
This chapter provides an overview of our present understanding of mechanisms of sensing protein folding status and endoplasmic reticulum (ER) stress in eukaryotic cells. The ER folds and matures most secretory and transmembrane proteins. Mis- or unfolded proteins are sensed by specialized ER stress sensors, such as IRE1, PERK and ATF6, which initiate several cellular responses and signaling pathways to restore ER homeostasis. These intracellular signaling events are called the unfolded protein response (UPR). Here we focus on how ER stress and protein folding status in the ER are sensed by the ER stress sensors by summarizing results from recent structural, biochemical and genetic approaches.
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20
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Endoplasmic reticulum stress and diabetic cardiomyopathy. EXPERIMENTAL DIABETES RESEARCH 2011; 2012:827971. [PMID: 22144992 PMCID: PMC3226330 DOI: 10.1155/2012/827971] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2011] [Revised: 09/06/2011] [Accepted: 09/07/2011] [Indexed: 01/02/2023]
Abstract
The endoplasmic reticulum (ER) is an organelle entrusted with lipid synthesis, calcium homeostasis, protein folding, and maturation. Perturbation of ER-associated functions results in an evolutionarily conserved cell stress response, the unfolded protein response (UPR) that is also called ER stress. ER stress is aimed initially at compensating for damage but can eventually trigger cell death if ER stress is excessive or prolonged. Now the ER stress has been associated with numerous diseases. For instance, our recent studies have demonstrated the important role of ER stress in diabetes-induced cardiac cell death. It is known that apoptosis has been considered to play a critical role in diabetic cardiomyopathy. Therefore, this paper will summarize the information from the literature and our own studies to focus on the pathological role of ER stress in the development of diabetic cardiomyopathy. Improved understanding of the molecular mechanisms underlying UPR activation and ER-initiated apoptosis in diabetic cardiomyopathy will provide us with new targets for drug discovery and therapeutic intervention.
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Rotavirus infection induces the unfolded protein response of the cell and controls it through the nonstructural protein NSP3. J Virol 2011; 85:12594-604. [PMID: 21937647 DOI: 10.1128/jvi.05620-11] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The unfolded protein response (UPR) is a cellular mechanism that is triggered in order to cope with the stress caused by the accumulation of misfolded proteins in the endoplasmic reticulum (ER). This response is initiated by the endoribonuclease inositol-requiring enzyme 1 (IRE1), activating transcription factor 6 (ATF6), and PKR-like ER kinase, which increase the expression of the genes involved in the folding and degradation processes and decrease the protein input into the ER by inhibiting translation. It has been shown that viruses both induce and manipulate the UPR in order to protect the host cells from an ER stress-mediated death, thus permitting the translation of viral proteins and the efficient replication of the virus. To understand the cellular events that occur during the rotavirus replication cycle, we examined the activation of the three UPR arms following infection, using luciferase reporters driven by promoters of the ER stress-responsive genes and real-time reverse transcription-PCR to determine the levels of the stress-induced mRNAs. Our findings indicated that during rotavirus infection two of the three arms of the UPR (IRE1 and ATF6) become activated; however, these pathways are interrupted at the translational level by the general inhibition of protein synthesis caused by NSP3. This response seems to be triggered by more than one viral protein synthesized during the replication of the virus, but not by the viral double-stranded RNA (dsRNA), since cells transfected with psoralen-inactivated virions, or with naked viral dsRNA, did not induce UPR.
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Fujimoto M, Hayashi T. New Insights into the Role of Mitochondria-Associated Endoplasmic Reticulum Membrane. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2011; 292:73-117. [DOI: 10.1016/b978-0-12-386033-0.00002-5] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Park S, Hwang H, Lee Y, You K, Shin K, Kwon O. Expression of endoplasmic reticulum chaperone ERP29 in the injured spinal cord. ACTA ACUST UNITED AC 2010. [DOI: 10.1080/12265071.2003.9647714] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Soojung Park
- a Department of Anatomy, College of Medicine , Chungnam National University , Taejon , 301–747 , Korea
| | - Ho‐Myung Hwang
- a Department of Anatomy, College of Medicine , Chungnam National University , Taejon , 301–747 , Korea
| | - Young‐Ho Lee
- a Department of Anatomy, College of Medicine , Chungnam National University , Taejon , 301–747 , Korea
| | - Kwan‐Hee You
- b Department of Biology, College of Natural Sciences , Chungnam National University , Taejon , 301–747 , Korea
| | - Kee‐Sun Shin
- c Korea Research Institute of Bioscience and Biotechnology , Taejon , 305–333 , Korea
| | - O‐Yu Kwon
- d Department of Anatomy, College of Medicine , Chungnam National University , Taejon , 301–747 , Korea Phone: Fax: E-mail:
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Cacas JL. Devil inside: does plant programmed cell death involve the endomembrane system? PLANT, CELL & ENVIRONMENT 2010; 33:1453-1473. [PMID: 20082668 DOI: 10.1111/j.1365-3040.2010.02117.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Eukaryotic cells have to constantly cope with environmental cues and integrate developmental signals. Cell survival or death is the only possible outcome. In the field of animal biology, tremendous efforts have been put into the understanding of mechanisms underlying cell fate decision. Distinct organelles have been proven to sense a broad range of stimuli and, if necessary, engage cell death signalling pathway(s). Over the years, forward and reverse genetic screens have uncovered numerous regulators of programmed cell death (PCD) in plants. However, to date, molecular networks are far from being deciphered and, apart from the autophagic compartment, no organelles have been assigned a clear role in the regulation of cellular suicide. The endomembrane system (ES) seems, nevertheless, to harbour a significant number of cell death mediators. In this review, the involvement of this system in the control of plant PCD is discussed in-depth, as well as compared and contrasted with what is known in animal and yeast systems.
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Affiliation(s)
- Jean-Luc Cacas
- Institut de Recherche pour le Développement, Equipe 2, Mécanismes des Résistances, Montpellier Cedex 5, France.
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Fujikawa T, Munakata T, Kondo SI, Satoh N, Wada S. Stress response in the ascidian Ciona intestinalis: transcriptional profiling of genes for the heat shock protein 70 chaperone system under heat stress and endoplasmic reticulum stress. Cell Stress Chaperones 2010; 15:193-204. [PMID: 19629754 PMCID: PMC2866982 DOI: 10.1007/s12192-009-0133-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2008] [Revised: 07/02/2009] [Accepted: 07/03/2009] [Indexed: 10/20/2022] Open
Abstract
The genome of Ciona intestinalis contains eight genes for HSP70 superfamily proteins, 36 genes for J-proteins, a gene for a J-like protein, and three genes for BAG family proteins. To understand the stress responses of genes in the HSP70 chaperone system comprehensively, the transcriptional profiles of these 48 genes under heat stress and endoplasmic reticulum (ER) stress were studied using real-time reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. Heat stress treatment increased the messenger RNA (mRNA) levels of six HSP70 superfamily genes, eight J-protein family genes, and two BAG family genes. In the cytoplasmic group of the DnaK subfamily of the HSP70 family, Ci-HSPA1/6/7-like was the only heat-inducible gene and Ci-HSPA2/8 was the only constitutively active gene which showed striking simplicity in comparison with other animals that have been examined genome-wide so far. Analyses of the time course and temperature dependency of the heat stress responses showed that the induction of Ci-HSPA1/6/7-like expression rises to a peak after heat stress treatment at 28 degrees C (10 degrees C upshift from control temperature) for 1 h. ER stress treatment with Brefeldin A, a drug that is known to act as ER stress inducer, increased the mRNA levels of four HSP70 superfamily genes and four J-protein family genes. Most stress-inducible genes are conserved between Ciona and vertebrates, as expected from a close evolutionary relationship between them. The present study characterized the stress responses of HSP70 chaperone system genes in Ciona for the first time and provides essential data for comprehensive understanding of the functions of the HSP70 chaperone system.
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Affiliation(s)
- Tetsuya Fujikawa
- Department of Bioscience, Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga 526-0829 Japan
| | - Takeo Munakata
- Department of Bioscience, Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga 526-0829 Japan
| | - Shin-ichi Kondo
- Department of Bioscience, Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga 526-0829 Japan
| | - Nori Satoh
- Marine Genomics Unit, Okinawa Institute of Science and Technology Promotion Corporation, Uruma, Okinawa 904-2234 Japan
| | - Shuichi Wada
- Department of Bioscience, Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga 526-0829 Japan
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Kawabe S, Yokoyama Y. Molecular cloning of calnexin and calreticulin in the Pacific oyster Crassostrea gigas and its expression in response to air exposure. Mar Genomics 2010; 3:19-27. [PMID: 21798193 DOI: 10.1016/j.margen.2010.01.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2009] [Revised: 12/18/2009] [Accepted: 01/11/2010] [Indexed: 10/19/2022]
Abstract
Calnexin (CNX) and calreticulin (CRT) are endoplasmic reticulum (ER) chaperones. CNX is a type I transmembrane protein and CRT is a soluble CNX homologue. In the ER, CNX and CRT are important for Ca(2+) homeostasis and protein maturation. Here, we describe the full-length cDNA of the first mollusk CNX (cgCNX) and a second mollusk CRT (cgCRT) from the oyster Crassostrea gigas. CgCNX, containing 3255bp, was composed of a 1764bp open reading frame (ORF) that encodes a 588-amino acid protein. CgCRT, containing 1727bp, was composed of a 1242bp ORF that encodes a 414-amino acid protein. CgCNX and cgCRT contains an N-terminal 21- and 16-amino acid sequence, respectively, which is characteristic of a signal sequence. At the C-terminus, cgCRT also contains the KDEL (-Lys-Asp-Glu-Leu) peptide motif suggesting that cgCRT localizes in the ER. Northern blot analysis showed that both cgCNX and cgCRT mRNAs are induced by air exposure. The expression patterns of cgCNX mRNA differed from those of cgCRT during air exposure. This suggests that these two molecular chaperones have different roles in the response to air exposure.
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Affiliation(s)
- Shinya Kawabe
- Department of Marine Bioscience, Fukui Prefectural University, Obama, Japan
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27
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cDNA cloning and expression of grp94 in the Pacific oyster Crassostrea gigas. Comp Biochem Physiol B Biochem Mol Biol 2009; 154:290-7. [DOI: 10.1016/j.cbpb.2009.07.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2009] [Revised: 06/29/2009] [Accepted: 07/05/2009] [Indexed: 01/10/2023]
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Short-term exposure to cadmium affects the expression of stress response and apoptosis-related genes in immortalized epithelial cells from the human breast. Toxicol In Vitro 2009; 23:943-9. [DOI: 10.1016/j.tiv.2009.04.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2008] [Revised: 04/16/2009] [Accepted: 04/28/2009] [Indexed: 11/17/2022]
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Mackiewicz M, Zimmerman JE, Shockley KR, Churchill GA, Pack AI. What are microarrays teaching us about sleep? Trends Mol Med 2009; 15:79-87. [PMID: 19162550 DOI: 10.1016/j.molmed.2008.12.002] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2008] [Revised: 12/09/2008] [Accepted: 12/09/2008] [Indexed: 01/10/2023]
Abstract
Many fundamental questions about sleep remain unanswered. The presence of sleep across phyla suggests that it must serve a basic cellular and/or molecular function. Microarray studies, performed in several model systems, have identified classes of genes that are sleep-state regulated. This has led to the following concepts: first, a function of sleep is to maintain synaptic homeostasis; second, sleep is a stage of macromolecule biosynthesis; third, extending wakefulness leads to downregulation of several important metabolic pathways; and, fourth, extending wakefulness leads to endoplasmic reticulum stress. In human studies, microarrays are being applied to the identification of biomarkers for sleepiness and for the common debilitating condition of obstructive sleep apnea.
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Chinta SJ, Poksay KS, Kaundinya G, Hart M, Bredesen DE, Andersen JK, Rao RV. Endoplasmic reticulum stress-induced cell death in dopaminergic cells: effect of resveratrol. J Mol Neurosci 2009; 39:157-68. [PMID: 19145491 DOI: 10.1007/s12031-008-9170-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2008] [Accepted: 12/17/2008] [Indexed: 01/24/2023]
Abstract
Resveratrol, a naturally occurring polyphenol, exhibits antioxidant, antiaging, and anticancer activity. Resveratrol has also been shown to inhibit tumor initiation, promotion, and progression in a variety of cell culture systems. Earlier, we showed that paraquat, a bipyridyl herbicide, triggers endoplasmic reticulum stress, cell dysfunction, and dopaminergic cell death. Due to its antioxidant activity, we assessed the ability of resveratrol to rescue cells from the toxic effects of paraquat. While resveratrol did not have any protective effect at low concentrations, it triggered endoplasmic reticulum (ER) stress-induced cell death at higher concentrations (50-250 microM). The present study was carried out to determine the mechanism by which resveratrol triggers ER stress and cell death in dopaminergic N27 cells. Our studies demonstrate that resveratrol triggers ER stress and cell dysfunction, caspase activation, p23 cleavage and inhibition of proteasomal activity in dopaminergic N27 cells. While over expression of uncleavable p23 was associated with decreased cell death, downregulation of p23 protein expression by siRNA resulted in enhancement of ER stress-induced cell death triggered by resveratrol indicating a protective role for the small co-chaperone p23 in dopaminergic cell death.
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Affiliation(s)
- Shankar J Chinta
- The Buck Institute for Age Research, 8001 Redwood Blvd., Novato, CA 94945, USA
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Bielek E. Membrane transformations in degenerating rodlet cells in fishes of two teleostean families (Salmonidae, Cyprinidae). Anat Rec (Hoboken) 2009; 291:1693-706. [PMID: 18951513 DOI: 10.1002/ar.20796] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Rodlet cells (RCs) of teleosts are identified by their fibrillar capsule and peculiar inclusions, the rodlets, consisting of a club-like sac and a central dense core. Former ultrastructural studies showing signs of hypertrophy of endoplasmic reticulum (ER) were followed up in Salmonids (Oncorhynchus mykiss, Salmo trutta L.) and compared with Cyprinids (Cyprinus carpio L., Carassius auratus L., Alburnus alburnus). Focusing on membrane transformations, unusual undulations of the membranes of rodlet sacs and often apposed ER-membranes, which were observed in mature or discharging cells, increased continuously in degenerating stages and ejected cytoplasmic packages or rodlets. Tubular elements (ø 25-30 nm or 30-50 nm) or small vesicles appeared partly derived from them. Terminal stages of this development were represented by RCs retained in the epithelium, which were completely filled by stacks of tubules and cores. Convoluted membranes were also found persisting between mostly undissolved rodlets at the epithelial surfaces. In Cyprinid species, the membrane changes were less conspicuous but essentially similar, including stages with confluent ER reported only in trout up to now. The membrane transformations resemble structures known as "crystalloid ER" indicating a disturbance in the protein production. The positive immunocytochemical reaction for calreticulin in the rodlet sacs, a luminal ER chaperone mediating recycling of misfolded proteins and upregulated during stress, supports this interpretation. The ER stress-reaction is an evolutionary conservative cytoprotective mechanism during physiological, environmental, and genetic aberrations and fits the increase of RCs reported in quite different situations, although details of its triggering need further investigation.
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Affiliation(s)
- Edith Bielek
- Centre of Anatomy and Cell Biology, Department of Nuclear-, Developmental Dynamics and Functional Microscopy, Medical University of Vienna, Vienna, Austria.
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Matoba S, Hiramatsu R, Kanai-Azuma M, Tsunekawa N, Harikae K, Kawakami H, Kurohmaru M, Kanai Y. Establishment of testis-specific SOX9 activation requires high-glucose metabolism in mouse sex differentiation. Dev Biol 2008; 324:76-87. [DOI: 10.1016/j.ydbio.2008.09.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2008] [Revised: 08/25/2008] [Accepted: 09/04/2008] [Indexed: 11/27/2022]
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Cameron J, Holla ØL, Laerdahl JK, Kulseth MA, Berge KE, Leren TP. Mutation S462P in the PCSK9 gene reduces secretion of mutant PCSK9 without affecting the autocatalytic cleavage. Atherosclerosis 2008; 203:161-5. [PMID: 19022446 DOI: 10.1016/j.atherosclerosis.2008.10.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Revised: 09/30/2008] [Accepted: 10/08/2008] [Indexed: 11/19/2022]
Abstract
OBJECTIVE The normal function of proprotein convertase subtilisin/kexin type 9 (PCSK9) is to mediate degradation of the low density lipoprotein (LDL) receptors. However, the exact mechanism for this function remains to be determined. Characterization of how the naturally occurring mutations in the PCSK9 gene affect the function of PCSK9, may provide important insight into the mechanism by which PCSK9 degrades the LDL receptors. METHODS DNA sequencing of the 12 exons with flanking intron sequences of the PCSK9 gene was performed in 1336 unrelated hypercholesterolemic subjects. In vitro assays and bioinformatics analysis were employed to characterize the functional consequences of a novel mutation. EXPERIMENTAL RESULTS: One subject was heterozygous for the novel mutation S462P in exon 9 of the PCSK9 gene. Based upon Western blot analysis of transiently transfected HepG2 cells, S462P-PCSK9 was almost completely retained in the endoplasmic reticulum (ER) even though it did undergo autocatalytic cleavage. Thus, only trace amounts of S462P-PCSK9 were detected in the culture media of transfected cells. Flow cytometric experiments revealed that the S462P-PCSK9 mutant was unable to degrade the LDL receptors. DISCUSSION The markedly reduced secretion of S462P-PCSK9 makes S462P a loss-of-function mutation. Ser462 is one of the few residues in the C-terminal domain which is conserved in all known PCSK9 homologs. A hydrogen bond between the side-chain of Ser462 and the backbone of beta-strand 6 of the C-terminal domain, appears to be essential for the proper folding of the C-terminal domain. The S462P mutation is believed to disrupt the normal folding of the C-terminal domain leading to retention of the mutant protein in the ER.
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Affiliation(s)
- Jamie Cameron
- Medical Genetics Laboratory, Department of Medical Genetics, Rikshospitalet University Hospital, NO-0027 Oslo, Norway
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Seo PJ, Kim SG, Park CM. Membrane-bound transcription factors in plants. TRENDS IN PLANT SCIENCE 2008; 13:550-6. [PMID: 18722803 DOI: 10.1016/j.tplants.2008.06.008] [Citation(s) in RCA: 145] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2008] [Revised: 06/19/2008] [Accepted: 06/20/2008] [Indexed: 05/03/2023]
Abstract
The ability to activate dormant transcription factors is an important molecular feature of the transcriptional regulatory networks that govern diverse cellular functions. An intriguing example is the controlled proteolytic activation of membrane-bound transcription factors (MTFs). Most MTFs are activated either by intramembrane proteases or by the ubiquitin-proteasome pathway. Recent studies have shown that several members of the bZIP and NAC families in Arabidopsis are membrane-associated and are activated by membrane-associated proteases during stress responses in the endoplasmic reticulum and when the plants experience environmental stresses. A genome-scale analysis shows that over 10% of all transcription factors are membrane bound, indicating that activation of MTFs occurs at the genomic level, allowing transcription to be regulated rapidly under stressful conditions.
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Affiliation(s)
- Pil Joon Seo
- Molecular Signaling Laboratory, Department of Chemistry, Seoul National University, Seoul 151-742, Korea
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Scharf MT, Naidoo N, Zimmerman JE, Pack AI. The energy hypothesis of sleep revisited. Prog Neurobiol 2008; 86:264-80. [PMID: 18809461 DOI: 10.1016/j.pneurobio.2008.08.003] [Citation(s) in RCA: 135] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2007] [Revised: 06/08/2008] [Accepted: 08/27/2008] [Indexed: 01/09/2023]
Abstract
One of the proposed functions of sleep is to replenish energy stores in the brain that have been depleted during wakefulness. Benington and Heller formulated a version of the energy hypothesis of sleep in terms of the metabolites adenosine and glycogen. They postulated that during wakefulness, adenosine increases and astrocytic glycogen decreases reflecting the increased energetic demand of wakefulness. We review recent studies on adenosine and glycogen stimulated by this hypothesis. We also discuss other evidence that wakefulness is an energetic challenge to the brain including the unfolded protein response, the electron transport chain, NPAS2, AMP-activated protein kinase, the astrocyte-neuron lactate shuttle, production of reactive oxygen species and uncoupling proteins. We believe the available evidence supports the notion that wakefulness is an energetic challenge to the brain, and that sleep restores energy balance in the brain, although the mechanisms by which this is accomplished are considerably more complex than envisaged by Benington and Heller.
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Affiliation(s)
- Matthew T Scharf
- Center for Sleep and Respiratory Neurobiology, University of Pennsylvania School of Medicine, Translational Research Building, Suite 2100, 125 S. 31st Street, Philadelphia, PA 19104-3403, USA.
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Sirchia R, Longo A, Luparello C. Cadmium regulation of apoptotic and stress response genes in tumoral and immortalized epithelial cells of the human breast. Biochimie 2008; 90:1578-90. [PMID: 18625282 DOI: 10.1016/j.biochi.2008.06.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2008] [Accepted: 06/19/2008] [Indexed: 01/23/2023]
Abstract
Cadmium (Cd) is a widely-disseminated metal which can be imported and accumulated in living cells thereby drastically interfering with their biological mechanisms. Increasing interest has been recently focused on the elucidation of the cellular and molecular aspects of Cd-dependent regulation of gene expression and signal transduction pathways in different model system. Concerning breast cancer, very limited studies have been produced so far on the role played by Cd on estrogen receptor-negative human breast cancer cells, that are expected to be insensitive to the already-proven metallo-estrogenic effect exerted by Cd on the estrogen receptor-positive cell counterparts. Here, we have examined the effects of long-term (96 h) exposure of estrogen receptor-negative MDA-MB231 malignant adenocarcinoma cells to CdCl(2) at 5 microM concentration, corresponding to the IC(50) for this time of incubation, by evaluating the expression levels of genes coding for stress response factors (e.g. heat shock proteins and metallothioneins), and for apoptosis-related factors and enzymes. In parallel, we tested the gene expression pattern of immortalized HB2 breast epithelial cells, taken as non-tumoral counterpart, after the same exposure to the metal which instead did not exert any change in their cell number with respect to controls. Our cumulative results indicate that, whilst HB2 cells appear to activate defense mechanisms against metal stress principally via metallothionein massive up-regulation and appearance of the spliced form of XBP-1 message, MDA-MB231 cells seem to couple the onset of a protective reaction (e.g. up-regulation of hsp27 and metallothioneins) to the switching-on of new intracellular pathways directing cells to a kind of death which shares several aspects with the apoptotic program, such as down-regulation of Bcl-2 and over-expression of Dap kinase and several caspases.
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Affiliation(s)
- Rosalia Sirchia
- Dipartimento di Biologia Cellulare e dello Sviluppo, Viale delle Scienze, Università di Palermo, Palermo, Italy
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Decreased ER-associated degradation of alpha-TCR induced by Grp78 depletion with the SubAB cytotoxin. Int J Biochem Cell Biol 2008; 40:2865-79. [PMID: 18611445 DOI: 10.1016/j.biocel.2008.06.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2008] [Revised: 06/09/2008] [Accepted: 06/10/2008] [Indexed: 02/07/2023]
Abstract
HeLa cells stably expressing the alpha chain of T-cell receptor (alphaTCR), a model substrate of ER-associated degradation (ERAD), were used to analyze the effects of BiP/Grp78 depletion by the SubAB cytotoxin. SubAB induced XBP1 splicing, followed by JNK phosphorylation, eIF2alpha phosphorylation, upregulation of ATF3/4 and partial ATF6 cleavage. Other markers of ER stress, including elements of ERAD pathway, as well as markers of cytoplasmic stress, were not induced. SubAB treatment decreased absolute levels of alphaTCR, which was caused by inhibition of protein synthesis. At the same time, the half-life of alphaTCR was extended almost fourfold from 70 min to 210 min, suggesting that BiP normally facilitates ERAD. Depletion of p97/VCP partially rescued SubAB-induced depletion of alphaTCR, confirming the role of VCP in ERAD of alphaTCR. It therefore appears that ERAD of alphaTCR is driven by at least two different ATP-ase systems located at two sides of the ER membrane, BiP located on the lumenal side, while p97/VCP on the cytoplasmic side. While SubAB altered cell morphology by inducing cytoplasm vacuolization and accumulation of lipid droplets, caspase activation was partial and subsided after prolonged incubation. Expression of CHOP/GADD153 occurred only after prolonged incubation and was not associated with apoptosis.
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Analysis of Npl4 deletion mutants in mammalian cells unravels new Ufd1-interacting motifs and suggests a regulatory role of Npl4 in ERAD. Exp Cell Res 2008; 314:2715-23. [PMID: 18586029 DOI: 10.1016/j.yexcr.2008.06.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2008] [Revised: 06/09/2008] [Accepted: 06/10/2008] [Indexed: 01/04/2023]
Abstract
Npl4 is a 67 kDa protein forming a stable heterodimer with Ufd1, which in turn binds the ubiquitous p97/VCP ATPase. According to a widely accepted model, VCP(Ufd1-Npl4) promotes the retrotranslocation of emerging ER proteins, their ubiquitination by associated ligases, and handling to the 26S proteasome for degradation in a process known as ERAD (ER-associated degradation). Using a series of Npl4 deletion mutants we have revealed that the binding of Ufd1 to Npl4 is mediated by two regions: a conserved stretch of amino acids from 113 to 255 within the zf-Npl4 domain and by the Npl4 homology domain between amino acids 263 and 344. Within the first region, we have identified two discrete subdomains: one involved in Ufd1 binding and one regulating VCP binding. Expression of any one of the mutants failed to induce any changes in the morphology of the ER or Golgi compartments. Moreover, we have observed that overexpression of all the analyzed mutants induced mild ER stress, as evidenced by increased Grp74/BiP expression without associated XBP1 splicing or induction of apoptosis. Surprisingly, we have not observed any accumulation of the typical ERAD substrate alphaTCR. This favors the model where the Ufd1-Npl4 dimer forms a regulatory gate at the exit from the retrotranslocone, rather than actively promoting retrotranslocation like the p97VCP ATPase.
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Burdakov D, Petersen OH, Verkhratsky A. Intraluminal calcium as a primary regulator of endoplasmic reticulum function. Cell Calcium 2008; 38:303-10. [PMID: 16076486 DOI: 10.1016/j.ceca.2005.06.010] [Citation(s) in RCA: 189] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2005] [Accepted: 06/28/2005] [Indexed: 01/11/2023]
Abstract
The concentration of Ca2+ inside the lumen of endoplasmic reticulum (ER) regulates a vast array of spatiotemporally distinct cellular processes, from intracellular Ca2+ signals to intra-ER protein processing and cell death. This review summarises recent data on the mechanisms of luminal Ca2+-dependent regulation of Ca2+ release and uptake as well as ER regulation of cellular adaptive processes. In addition we discuss general biophysical properties of the ER membrane, as trans-endomembrane Ca2+ fluxes are subject to basic electrical forces, determined by factors such as the membrane potential of the ER and the ease with which Ca2+ fluxes are able to change this potential (i.e. the resistance of the ER membrane). Although these electrical forces undoubtedly play a fundamental role in shaping [Ca2+](ER) dynamics, at present there is very little direct experimental information about the biophysical properties of the ER membrane. Further studies of how intraluminal [Ca2+] is regulated, best carried out with direct measurements, are vital for understanding how Ca2+ orchestrates cell function. Direct monitoring of [Ca2+](ER) under conditions where the cytosolic [Ca2+] is known may also help to capture elusive biophysical information about the ER, such as the potential difference across the ER membrane.
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Affiliation(s)
- Denis Burdakov
- Faculty of Life Sciences, The University of Manchester, 1.124 Stopford Building, Oxford Road, Manchester M13 9PT, UK
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40
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Mackiewicz M, Naidoo N, Zimmerman JE, Pack AI. Molecular Mechanisms of Sleep and Wakefulness. Ann N Y Acad Sci 2008; 1129:335-49. [DOI: 10.1196/annals.1417.030] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Cameron J, Holla OL, Laerdahl JK, Kulseth MA, Ranheim T, Rognes T, Berge KE, Leren TP. Characterization of novel mutations in the catalytic domain of the PCSK9 gene. J Intern Med 2008; 263:420-31. [PMID: 18266662 DOI: 10.1111/j.1365-2796.2007.01915.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
OBJECTIVES To expand our understanding of the structure and function of proprotein convertase subtilisin/kexin type 9 (PCSK9) by studying how naturally occurring mutations in PCSK9 disrupt the function of PCSK9. DESIGN Mutations in PCSK9 were identified by sequencing of DNA from subjects with hypo- or hypercholesterolemia. The effect of the identified mutations on the autocatalytic cleavage and secretion of PCSK9, as well as the effect on PCSK9-mediated degradation of the low density lipoprotein receptors, were determined in HepG2 or HEK293 cells transiently transfected with mutant PCSK9-containing plasmids. The findings were collated to the clinical characteristics of the subjects possessing these mutations, and the phenotypic effects were analysed in terms of available structural data for PCSK9. RESULTS Five novel mutations in PCSK9 were identified. Mutation R215H was a gain-of-function mutation which causes hypercholesterolemia. Mutation G236S and N354I were loss-of-function mutations due to failure to exit the endoplasmic reticulum or failure to undergo autocatalytic cleavage, respectively. Mutations A245T and R272Q were most likely normal genetic variants. By comparing the number of patients with gain-of-function mutations in PCSK9 with the number of familial hypercholesterolemia heterozygotes among subjects with hypercholesterolemia, the prevalence of subjects with gain-of-function mutations in PCSK9 in Norway can be estimated to one in 15,000. CONCLUSION This study has provided novel information about the structural requirements for the normal function of PCSK9. However, more studies are needed to determine the mechanisms by which gain-of-function mutations in PCSK9 cause hypercholesterolemia.
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Affiliation(s)
- J Cameron
- Department of Medical Genetics, Medical Genetics Laboratory, Rigshospitalet-Radiumhospitalet Medical Centre, Oslo, Norway
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A pharmacoproteomic approach implicates eukaryotic elongation factor 2 kinase in ER stress-induced cell death. Cell Death Differ 2008; 15:589-99. [PMID: 18188169 DOI: 10.1038/sj.cdd.4402296] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Apoptosis triggered by endoplasmic reticulum (ER) stress has been implicated in many diseases but its cellular regulation remains poorly understood. Previously, we identified salubrinal (sal), a small molecule that protects cells from ER stress-induced apoptosis by selectively activating a subset of endogenous ER stress-signaling events. Here, we use sal as a probe in a proteomic approach to discover new information about the endogenous cellular response to ER stress. We show that sal induces phosphorylation of the translation elongation factor eukaryotic translation elongation factor 2 (eEF-2), an event that depends on eEF-2 kinase (eEF-2K). ER stress itself also induces eEF-2K-dependent eEF-2 phosphorylation, and this pathway promotes translational arrest and cell death in this context, identifying eEF-2K as a hitherto unknown regulator of ER stress-induced apoptosis. Finally, we use both sal and ER stress models to show that eEF-2 phosphorylation can be activated by at least two signaling mechanisms. Our work identifies eEF-2K as a new component of the ER stress response and underlines the utility of novel small molecules in discovering new cell biology.
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Glushchenko AV, Jacobsen DW. Molecular targeting of proteins by L-homocysteine: mechanistic implications for vascular disease. Antioxid Redox Signal 2007; 9:1883-98. [PMID: 17760510 PMCID: PMC2855132 DOI: 10.1089/ars.2007.1809] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Hyperhomocysteinemia is an independent risk factor for cardiovascular disease, complications of pregnancy, cognitive impairment, and osteoporosis. That elevated homocysteine leads to vascular dysfunction may be the linking factor between these apparently unrelated pathologies. Although a growing body of evidence suggests that homocysteine plays a causal role in atherogenesis, specific mechanisms to explain the underlying pathogenesis have remained elusive. This review focuses on chemistry unique to the homocysteine molecule to explain its inherent cytotoxicity. Thus, the high pKa of the sulfhydryl group (pKa, 10.0) of homocysteine underlies its ability to form stable disulfide bonds with protein cysteine residues, and in the process, alters or impairs the function of the protein. Studies in this laboratory have identified albumin, fibronectin, transthyretin, and metallothionein as targets for homocysteinylation. In the case of albumin, the mechanism of targeting has been elucidated. Homocysteinylation of the cysteine residues of fibronectin impairs its ability to bind to fibrin. Homocysteinylation of the cysteine residues of metallothionein disrupts zinc binding by the protein and abrogates inherent superoxide dismutase activity. Thus, S-homocysteinylation of protein cysteine residues may explain mechanistically the cytotoxicity of elevated L-homocysteine.
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Affiliation(s)
- Alla V. Glushchenko
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Donald W. Jacobsen
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, Ohio
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Wang L, Zhuo Y, Liu B, Huang S, Hou F, Ge J. Pro370Leu mutant myocilin disturbs the endoplasm reticulum stress response and mitochondrial membrane potential in human trabecular meshwork cells. Mol Vis 2007; 13:618-25. [PMID: 17515882 PMCID: PMC2669509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
PURPOSE To investigate the impact of Pro370Leu mutant myocilin on endoplasmic reticulum (ER) stress response and mitochondria function in human trabecular meshwork (HTM) cells. METHODS HTM cells were transfected with wild-type Pro370Leu mutant myocilin or pcDNA3.1 (+) expression plasmids. The effect of the mutant myocilin on ER stress response was semiquantitatively evaluated by determining the expression level of 78 kDa glucose-regulated protein (GRP78) using reverse transcription-polymerase chain reaction and phosphorylation of the alpha subunit of eukaryotic translation initiation factor 2 (eIF2alpha) using western blot analysis. Mitochondria function was determined by analyzing the changes in mitochondrial membrane potential (Deltapsim), measured by flow cytometry analysis using the fluorescent probe JC-1. RESULTS Pro370Leu mutant myocilin attenuated the induction of GRP78 and the phosphorylation of eIF2alpha. In HTM cells expressing the mutant myocilin, the reductions were evident in the level of GRP78 mRNA (65.5+/-2.0%), GRP78 protein (22.5+/-2.3%), and eIF2alpha phosphorylation (30.6+/-2.6%), compared to cells transfected with the wild-type myocilin plasmid (p less than or equal to 0.05). There was no significant difference between wild-type-myocilin- and pcDNA3.1(+)-transfected cells. Furthermore, Pro370Leu mutant myocilin caused a collapse of Deltapsim in HTM cells. CONCLUSIONS Pro370Leu mutant myocilin down-regulates the ER stress response and destroys the Deltapsim of HTM cells. These observations suggest that Pro370Leu mutant myocilin could affect ER and mitochondria function through a gain of function, increasing its vulnerability to various cellular injuries and producing dysfunctional HTM cells.
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45
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Sasaki Y. Does oxidative stress participate in the development of hepatocellular carcinoma? J Gastroenterol 2006; 41:1135-48. [PMID: 17287893 DOI: 10.1007/s00535-006-1982-z] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2006] [Accepted: 12/06/2006] [Indexed: 02/04/2023]
Affiliation(s)
- Yutaka Sasaki
- Department of Gastroenterology and Hepatology, Graduate School of Medical Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 860-8556, Japan
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Mimnaugh EG, Xu W, Vos M, Yuan X, Neckers L. Endoplasmic Reticulum Vacuolization and Valosin-Containing Protein Relocalization Result from Simultaneous Hsp90 Inhibition by Geldanamycin and Proteasome Inhibition by Velcade. Mol Cancer Res 2006; 4:667-81. [PMID: 16966435 DOI: 10.1158/1541-7786.mcr-06-0019] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Geldanamycin and Velcade, new anticancer drugs with novel mechanisms of action, are currently undergoing extensive clinical trials. Geldanamycin interrupts Hsp90 chaperone activity and causes down-regulation of its many client proteins by the ubiquitin-proteasome pathway; Velcade is a specific proteasome inhibitor. Misfolded Hsp90 clients within the endoplasmic reticulum (ER) lumen are cleared by ER--associated protein degradation, a sequential process requiring valosin-containing protein (VCP)-dependent retrotranslocation followed by ubiquitination and proteasomal proteolysis. Cotreatment of cells with geldanamycin and Velcade prevents destruction of destabilized, ubiquitinated Hsp90 client proteins, causing them to accumulate. Here, we report that misfolded protein accumulation within the ER resulting from geldanamycin and Velcade exposure overwhelms the ability of the VCP--centered machine to maintain the ER secretory pathway, causing the ER to distend into conspicuous vacuoles. Overexpression of dominant-negative VCP or the "small VCP--interacting protein" exactly recapitulated the vacuolated phenotype provoked by the drugs, associating loss of VCP function with ER vacuolization. In cells transfected with a VCP--enhanced yellow fluorescent protein fluorescent construct, geldanamycin plus Velcade treatment redistributed VCP--enhanced yellow fluorescent protein from the cytoplasm and ER into perinuclear aggresomes. In further support of the view that compromise of VCP function is responsible for ER vacuolization, small interfering RNA interference of VCP expression induced ER vacuolization that was markedly increased by Velcade. VCP knockdown by small interfering RNA eventually deconstructed both the ER and Golgi and interdicted protein trafficking through the secretory pathway to the plasma membrane. Thus, simultaneous geldanamycin and Velcade treatment has far-reaching secondary cytotoxic consequences that likely contribute to the cytotoxic activity of this anticancer drug combination.
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Affiliation(s)
- Edward G Mimnaugh
- Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, NIH, 9000 Rockville Pike, Building 10, Room 1-5940, Bethesda, MD 20892-1107, USA
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47
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Görlach A, Klappa P, Kietzmann T. The endoplasmic reticulum: folding, calcium homeostasis, signaling, and redox control. Antioxid Redox Signal 2006; 8:1391-418. [PMID: 16986999 DOI: 10.1089/ars.2006.8.1391] [Citation(s) in RCA: 493] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The endoplasmic reticulum (ER) plays a major role in regulating synthesis, folding, and orderly transport of proteins. It is also essentially involved in various cellular signaling processes, primarily by its function as a dynamic Ca(2+) store. Compared to the cytosol, oxidizing conditions are found in the ER that allow oxidation of cysteine residues in nascent polypeptide chains to form intramolecular disulfide bonds. However, compounds and enzymes such as PDI that catalyze disulfide bonds become reduced and have to be reoxidized for further catalytic cycles. A number of enzymes, among them products of the ERO1 gene, appear to provide oxidizing equivalents, and oxygen appears to be the final oxidant in aerobic living organisms. Thus, protein oxidation in the ER is connected with generation of reactive oxygen species (ROS). Changes in the redox state and the presence of ROS also affect the Ca(2+) homeostasis by modulating the functionality of ER-based channels and buffering chaperones. In addition, a close relationship exists between oxidative stress and ER stress, which both may activate signaling events leading to a rebalance of folding capacity and folding demand or to cell death. Thus, redox homeostasis appears to be a prerequisite for proper functioning of the ER.
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Affiliation(s)
- Agnes Görlach
- Experimental Pediatric Cardiology, Department of Pediatric Cardiology and Congenital Heart Disease, German Heart Center Munich at the Technical University Munich, Munich, Germany
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Wójcik C, Rowicka M, Kudlicki A, Nowis D, McConnell E, Kujawa M, DeMartino GN. Valosin-containing protein (p97) is a regulator of endoplasmic reticulum stress and of the degradation of N-end rule and ubiquitin-fusion degradation pathway substrates in mammalian cells. Mol Biol Cell 2006; 17:4606-18. [PMID: 16914519 PMCID: PMC1635394 DOI: 10.1091/mbc.e06-05-0432] [Citation(s) in RCA: 151] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Valosin-containing protein (VCP; p97; cdc48 in yeast) is a hexameric ATPase of the AAA family (ATPases with multiple cellular activities) involved in multiple cellular functions, including degradation of proteins by the ubiquitin (Ub)-proteasome system (UPS). We examined the consequences of the reduction of VCP levels after RNA interference (RNAi) of VCP. A new stringent method of microarray analysis demonstrated that only four transcripts were nonspecifically affected by RNAi, whereas approximately 30 transcripts were affected in response to reduced VCP levels in a sequence-independent manner. These transcripts encoded proteins involved in endoplasmic reticulum (ER) stress, apoptosis, and amino acid starvation. RNAi of VCP promoted the unfolded protein response, without eliciting a cytosolic stress response. RNAi of VCP inhibited the degradation of R-GFP (green fluorescent protein) and Ub-(G76V)-GFP, two cytoplasmic reporter proteins degraded by the UPS, and of alpha chain of the T-cell receptor, an established substrate of the ER-associated degradation (ERAD) pathway. Surprisingly, RNAi of VCP had no detectable effect on the degradation of two other ERAD substrates, alpha1-antitrypsin and deltaCD3. These results indicate that VCP is required for maintenance of normal ER structure and function and mediates the degradation of some proteins via the UPS, but is dispensable for the UPS-dependent degradation of some ERAD substrates.
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Affiliation(s)
- Cezary Wójcik
- *Department of Anatomy and Cell Biology, Indiana University School of Medicine, Evansville, IN 47712
- Departments of Physiology and
| | - Maga Rowicka
- Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390; and
| | - Andrzej Kudlicki
- Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390; and
| | - Dominika Nowis
- *Department of Anatomy and Cell Biology, Indiana University School of Medicine, Evansville, IN 47712
| | - Elizabeth McConnell
- *Department of Anatomy and Cell Biology, Indiana University School of Medicine, Evansville, IN 47712
| | - Marek Kujawa
- Department of Histology and Embryology, Medical University of Warsaw, 02-004 Warsaw, Poland
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Nowis D, McConnell E, Wójcik C. Destabilization of the VCP-Ufd1-Npl4 complex is associated with decreased levels of ERAD substrates. Exp Cell Res 2006; 312:2921-32. [PMID: 16822501 DOI: 10.1016/j.yexcr.2006.05.013] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2006] [Revised: 05/16/2006] [Accepted: 05/28/2006] [Indexed: 10/24/2022]
Abstract
p97/VCP associated with Ufd1-Npl4 is considered a key player in ER-associated degradation (ERAD). RNA interference (RNAi) of one component of the Ufd1-Npl4 heterodimer destabilizes the VCP-Ufd1-Npl4 complex inducing proteasome-dependent degradation of the other component and releasing free VCP. In contrast to RNAi of VCP, RNAi of Ufd1 or Npl4 depleting approximately 90% of the VCP-Ufd1-Npl4 complexes does not induce unfolded protein response, indicating that the Ufd1-Npl4 dimer is not involved in the regulation of ER function by VCP. RNAi of Ufd1 or Npl4 is associated with a 2-fold increase in the levels of polyubiquitinated proteins, which form dispersed aggregates often associated with calnexin-positive structures. However, contrary to the effects of proteasome inhibition, RNAi of Ufd1 or Npl4 does not induce an accumulation of alpha-TCR and delta-CD3, two ERAD substrates overexpressed in HeLa cells. Instead, a 60-70% decrease in their levels is observed. The decrease in alpha-TCR levels is associated with a 50% decrease of its half-life. Upregulation of the putative channel forming protein, derlin-1, may contribute to the increased degradation of ERAD substrates. To explain our findings, we propose a model, where association of emerging ERAD substrates with VCP-Ufd1-Npl4 is not required for their degradation but has a regulatory role.
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Affiliation(s)
- Dominika Nowis
- Department of Anatomy and Cell Biology, Indiana University School of Medicine-Evansville, 8600 University Boulevard, Evansville, IN 47712, USA
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50
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Estrada de Martin P, Novick P, Ferro-Novick S. The organization, structure, and inheritance of the ER in higher and lower eukaryotes. Biochem Cell Biol 2006; 83:752-61. [PMID: 16333327 DOI: 10.1139/o05-159] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The endoplasmic reticulum (ER) is a fundamental organelle required for protein assembly, lipid biosynthesis, and vesicular traffic, as well as calcium storage and the controlled release of calcium from the ER lumen into the cytosol. Membranes functionally linked to the ER by vesicle-mediated transport, such as the Golgi complex, endosomes, vacuoles-lysosomes, secretory vesicles, and the plasma membrane, originate largely from proteins and lipids synthesized in the ER. In this review we will discuss the structural organization of the ER and its inheritance.
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Affiliation(s)
- Paula Estrada de Martin
- Department of Cell Biology, Yale University School of Medicine, Boyer Center for Molecular Medicine, New Haven, CT 06519, USA
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