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Monnerie H, Romer M, Roth LM, Long C, Millar JS, Jordan-Sciutto KL, Grinspan JB. Inhibition of lipid synthesis by the HIV integrase strand transfer inhibitor elvitegravir in primary rat oligodendrocyte cultures. Front Mol Neurosci 2023; 16:1323431. [PMID: 38146334 PMCID: PMC10749327 DOI: 10.3389/fnmol.2023.1323431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 11/22/2023] [Indexed: 12/27/2023] Open
Abstract
Combined antiretroviral therapy (cART) has greatly decreased mortality and morbidity among persons with HIV; however, neurologic impairments remain prevalent, in particular HIV-associated neurocognitive disorders (HANDs). White matter damage persists in cART-treated persons with HIV and may contribute to neurocognitive dysfunction as the lipid-rich myelin membrane of oligodendrocytes is essential for efficient nerve conduction. Because of the importance of lipids to proper myelination, we examined the regulation of lipid synthesis in oligodendrocyte cultures exposed to the integrase strand transfer inhibitor elvitegravir (EVG), which is administered to persons with HIV as part of their initial regimen. We show that protein levels of genes involved in the fatty acid pathway were reduced, which correlated with greatly diminished de novo levels of fatty acid synthesis. In addition, major regulators of cellular lipid metabolism, the sterol regulatory element-binding proteins (SREBP) 1 and 2, were strikingly altered following exposure to EVG. Impaired oligodendrocyte differentiation manifested as a marked reduction in mature oligodendrocytes. Interestingly, most of these deleterious effects could be prevented by adding serum albumin, a clinically approved neuroprotectant. These new findings, together with our previous study, strengthen the possibility that antiretroviral therapy, at least partially through lipid dysregulation, may contribute to the persistence of white matter changes observed in persons with HIV and that some antiretrovirals may be preferable as life-long therapy.
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Affiliation(s)
- Hubert Monnerie
- Department of Neurology, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | - Micah Romer
- Department of Neurology, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | - Lindsay M. Roth
- Department of Neurology, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | - Caela Long
- Department of Neurology, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | - John S. Millar
- Institute of Diabetes, Obesity and Metabolism, University of Pennsylvania, Philadelphia, PA, United States
| | - Kelly L. Jordan-Sciutto
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Judith B. Grinspan
- Department of Neurology, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
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2
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Yin J, Fu J, Shao Y, Xu J, Li H, Chen C, Zhao Y, Zheng Z, Yu C, Zheng L, Wang B. CYP51-mediated cholesterol biosynthesis is required for the proliferation of CD4 + T cells in Sjogren's syndrome. Clin Exp Med 2023; 23:1691-1711. [PMID: 36413274 DOI: 10.1007/s10238-022-00939-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 11/02/2022] [Indexed: 11/23/2022]
Abstract
CYtochrome P450, family 51 (CYP51) is an important enzyme for de novo cholesterol synthesis in mammalian cells. In the present study, we found that the expression of CYP51 positively correlated with CD4+ T cell activation both in vivo and in vitro. The addition of ketoconazole, a pharmacological inhibitor of CYP51, prevented the proliferation and activation of anti-CD3/CD28-expanded mouse CD4+ T cells in a dose-dependent fashion. Liquid chromatography-tandem mass spectrometry indicated an increase in levels of lanosterol in T cells treated with ketoconazole during activation. Ketoconazole-induced blockade of the cholesterol synthesis pathway also caused Sterol regulatory element binding protein 2 (SREBP2) activation in CD4+ T cells. Additionally, ketoconazole treatment elicited an integrated stress response in T cells that up-regulated activating transcription factor 4 (ATF4) and DNA-damage inducible transcript 3 (DDIT3/CHOP) at the translational level. Furthermore, treatment with ketoconazole significantly decreased the amount of CD4+ T cells infiltrating lesions in the submandibular glands of NOD/Ltj mice. In summary, our results suggest that CYP51 plays an essential role in the proliferation and survival of CD4+ T cells, which makes ketoconazole an inhibitor of CD4+ T cell proliferation and of the SS-like autoimmune response through regulating the biosynthesis of cholesterol and inducing the integrated stress response.
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Affiliation(s)
- Junhao Yin
- Department of Oral Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, College of Stomatology, Shanghai Jiao Tong University, Shanghai, China
- National Center for Stomatology & National Clinical Research Center for Oral Disease, Shanghai, China
- Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Jiayao Fu
- Department of Oral Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, College of Stomatology, Shanghai Jiao Tong University, Shanghai, China
- National Center for Stomatology & National Clinical Research Center for Oral Disease, Shanghai, China
- Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Yanxiong Shao
- Department of Oral Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, College of Stomatology, Shanghai Jiao Tong University, Shanghai, China
- National Center for Stomatology & National Clinical Research Center for Oral Disease, Shanghai, China
- Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Jiabao Xu
- Department of Oral Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, College of Stomatology, Shanghai Jiao Tong University, Shanghai, China
- National Center for Stomatology & National Clinical Research Center for Oral Disease, Shanghai, China
- Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Hui Li
- Department of Oral Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, College of Stomatology, Shanghai Jiao Tong University, Shanghai, China
- National Center for Stomatology & National Clinical Research Center for Oral Disease, Shanghai, China
- Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Changyu Chen
- Department of Oral Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, College of Stomatology, Shanghai Jiao Tong University, Shanghai, China
- National Center for Stomatology & National Clinical Research Center for Oral Disease, Shanghai, China
- Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Yijie Zhao
- Department of Oral and Maxillofacial Surgery, Shanghai Stomatological Hospital, Fudan University, 1258 Fuxin Zhong Road, Shanghai, China
| | - Zhanglong Zheng
- Department of Oral and Maxillofacial Surgery, School and Hospital of Stomatology, Tongji University, Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai, China
| | - Chuangqi Yu
- Department of Oral Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, College of Stomatology, Shanghai Jiao Tong University, Shanghai, China
- National Center for Stomatology & National Clinical Research Center for Oral Disease, Shanghai, China
- Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Lingyan Zheng
- Department of Oral Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, College of Stomatology, Shanghai Jiao Tong University, Shanghai, China.
- National Center for Stomatology & National Clinical Research Center for Oral Disease, Shanghai, China.
- Shanghai Key Laboratory of Stomatology, Shanghai, China.
| | - Baoli Wang
- Department of Oral Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, College of Stomatology, Shanghai Jiao Tong University, Shanghai, China.
- National Center for Stomatology & National Clinical Research Center for Oral Disease, Shanghai, China.
- Shanghai Key Laboratory of Stomatology, Shanghai, China.
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3
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Lee G, Kim YY, Jang H, Han JS, Nahmgoong H, Park YJ, Han SM, Cho C, Lim S, Noh JR, Oh WK, Lee CH, Kim S, Kim JB. SREBP1c-PARP1 axis tunes anti-senescence activity of adipocytes and ameliorates metabolic imbalance in obesity. Cell Metab 2022; 34:702-718.e5. [PMID: 35417665 DOI: 10.1016/j.cmet.2022.03.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 12/28/2021] [Accepted: 03/23/2022] [Indexed: 01/10/2023]
Abstract
Emerging evidence indicates that the accretion of senescent cells is linked to metabolic disorders. However, the underlying mechanisms and metabolic consequences of cellular senescence in obesity remain obscure. In this study, we found that obese adipocytes are senescence-susceptible cells accompanied with genome instability. Additionally, we discovered that SREBP1c may play a key role in genome stability and senescence in adipocytes by modulating DNA-damage responses. Unexpectedly, SREBP1c interacted with PARP1 and potentiated PARP1 activity during DNA repair, independent of its canonical lipogenic function. The genetic depletion of SREBP1c accelerated adipocyte senescence, leading to immune cell recruitment into obese adipose tissue. These deleterious effects provoked unhealthy adipose tissue remodeling and insulin resistance in obesity. In contrast, the elimination of senescent adipocytes alleviated adipose tissue inflammation and improved insulin resistance. These findings revealed distinctive roles of SREBP1c-PARP1 axis in the regulation of adipocyte senescence and will help decipher the metabolic significance of senescence in obesity.
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Affiliation(s)
- Gung Lee
- Center for Adipocyte Structure and Function, Institute of Molecular Biology and Genetics, School of Biological Sciences, Seoul National University, Seoul 08826, South Korea
| | - Ye Young Kim
- Center for Adipocyte Structure and Function, Institute of Molecular Biology and Genetics, School of Biological Sciences, Seoul National University, Seoul 08826, South Korea
| | - Hagoon Jang
- Center for Adipocyte Structure and Function, Institute of Molecular Biology and Genetics, School of Biological Sciences, Seoul National University, Seoul 08826, South Korea
| | - Ji Seul Han
- Center for Adipocyte Structure and Function, Institute of Molecular Biology and Genetics, School of Biological Sciences, Seoul National University, Seoul 08826, South Korea
| | - Hahn Nahmgoong
- Center for Adipocyte Structure and Function, Institute of Molecular Biology and Genetics, School of Biological Sciences, Seoul National University, Seoul 08826, South Korea
| | - Yoon Jeong Park
- Center for Adipocyte Structure and Function, Institute of Molecular Biology and Genetics, School of Biological Sciences, Seoul National University, Seoul 08826, South Korea
| | - Sang Mun Han
- Center for Adipocyte Structure and Function, Institute of Molecular Biology and Genetics, School of Biological Sciences, Seoul National University, Seoul 08826, South Korea
| | - Changyun Cho
- Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul 08826, South Korea
| | - Sangsoo Lim
- Bioinformatics Institute, Seoul National University, Seoul 08826, South Korea
| | - Jung-Ran Noh
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology, University of Science and Technology, Yuseong-gu, Daejeon 34141, South Korea
| | - Won Keun Oh
- Korea Bioactive Natural Material Bank, Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 08826, South Korea
| | - Chul-Ho Lee
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology, University of Science and Technology, Yuseong-gu, Daejeon 34141, South Korea
| | - Sun Kim
- Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul 08826, South Korea; Bioinformatics Institute, Seoul National University, Seoul 08826, South Korea; Department of Computer Science and Engineering, Institute of Engineering Research, Seoul National University, Seoul 08826, South Korea
| | - Jae Bum Kim
- Center for Adipocyte Structure and Function, Institute of Molecular Biology and Genetics, School of Biological Sciences, Seoul National University, Seoul 08826, South Korea.
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4
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Samluk L, Ostapczuk P, Dziembowska M. Long-term mitochondrial stress induces early steps of Tau aggregation by increasing reactive oxygen species levels and affecting cellular proteostasis. Mol Biol Cell 2022; 33:ar67. [PMID: 35446108 PMCID: PMC9635289 DOI: 10.1091/mbc.e21-11-0553] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Accumulating evidence indicates that mitochondrial dysfunction is involved in the pathogenesis of neurodegenerative diseases. Both of these conditions are often associated with an increase in protein aggregation. However, still unknown are the specific defects of mitochondrial biology that play a critical role in the development of Alzheimer’s disease, in which Tau protein aggregates are observed in the brains of some patients. Here, we report that long-term mitochondrial stress triggered Tau dimerization, which is the first step of protein aggregation. Mitochondrial dysfunction was induced in HEK293T cells that received prolonged treatment with rotenone and in HEK293T cells with the knockout of NDUFA11 protein. To monitor changes in Tau protein aggregation, we took advantage of the bimolecular fluorescence complementation assay using HEK293T cells that were transfected with plasmids that encoded Tau. Inhibition of the ISR with ISRIB induced Tau dimerization, whereas ISR activation with salubrinal, guanabenz, and sephin1 partially reversed this process. Cells that were treated with ROS scavengers, N-acetyl-l-cysteine or MitoQ, significantly reduced the amount of ROS and Tau dimerization, indicating the involvement of oxidative stress in Tau aggregation. Our results indicate that long-term mitochondrial stress may induce early steps of Tau protein aggregation by affecting oxidative balance and cellular proteostasis.
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Affiliation(s)
- Lukasz Samluk
- Centre of New Technologies, University of Warsaw, S. Banacha 2c, 02-097 Warsaw, Poland
| | - Piotr Ostapczuk
- Centre of New Technologies, University of Warsaw, S. Banacha 2c, 02-097 Warsaw, Poland
| | - Magdalena Dziembowska
- Centre of New Technologies, University of Warsaw, S. Banacha 2c, 02-097 Warsaw, Poland
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5
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Ghafouri M, Gauss CB, Fribley AM. HTS Identification of Activators and Inhibitors of Endoplasmic Reticulum (ER) Stress and the Unfolded Protein Response (UPR). Methods Mol Biol 2022; 2378:317-327. [PMID: 34985709 DOI: 10.1007/978-1-0716-1732-8_20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The identification of small molecules and natural product extracts that enhance or interfere with the productivity of protein folding in the endoplasmic reticulum (ER) has the potential to improve a wide variety of human pathologies. Every protein that is destined for a lysosome, integral to the cell membrane, or secreted, is folded, post-translationally modified, and exported to the cytoplasm from the ER-Golgi complex. The following protocols have successfully employed several high-fidelity cell-based luciferase high-throughput screens (HTS) to identify activators and inhibitors of ER stress and the unfolded protein response (UPR).
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Affiliation(s)
- Mehrnoosh Ghafouri
- Carman and Ann Adams Department of Pediatrics, Wayne State University School of Medicine, Detroit, MI, USA
| | - Chester B Gauss
- Carman and Ann Adams Department of Pediatrics, Wayne State University School of Medicine, Detroit, MI, USA
| | - Andrew M Fribley
- Carman and Ann Adams Department of Pediatrics, Wayne State University School of Medicine, Detroit, MI, USA.
- Department of Otolaryngology-Head and Neck Surgery, Wayne State University School of Medicine, Detroit, MI, USA.
- Molecular Therapeutics Program, Barbara Ann Karmanos Cancer Institute, Detroit, MI, USA.
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6
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Le F, Wang N, Wang Q, Yang X, Li L, Wang L, Liu X, Hu M, Jin F, Lou H. Long-Term Disturbed Expression and DNA Methylation of SCAP/SREBP Signaling in the Mouse Lung From Assisted Reproductive Technologies. Front Genet 2021; 12:566168. [PMID: 34249075 PMCID: PMC8266399 DOI: 10.3389/fgene.2021.566168] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 05/24/2021] [Indexed: 11/16/2022] Open
Abstract
Assisted reproductive technology (ART) has been linked to cholesterol metabolic and respiratory disorders later in life, but the mechanisms by which biosynthetic signaling remain unclear. Lung inflammatory diseases are tightly linked with the sterol regulatory element-binding protein (SREBP) and SREBP cleavage-activating protein (SCAP), but this has not been shown in an ART offspring. Here, mouse models from a young to old age were established including in vitro fertilization (IVF), intracytoplasmic injection (ICSI), and in vivo fertilized groups. In our results, significantly higher plasma levels of CRP, IgM, and IgG were identified in the aged ICSI mice. Additionally, pulmonary inflammation was found in four aged ART mice. At three weeks, ART mice showed significantly downregulated levels of Scap, Srebp-1a, Srebp-1c, and Srebf2 mRNA in the lung. At the same time, significant differences in the DNA methylation rates of Scap-Srebfs and protein expression of nuclear forms of SREBPs (nSREBPs) were detected in the ART groups. Only abnormalities in the expression levels of Srebp-1a and Srebp-1c mRNA and nSREBP1 protein were found in the ART groups at 10 weeks. However, at 1.5 years old, aberrant expression levels and DNA methylation of SCAP, SREBP1, and SREBP2, and their associated target genes, were observed in the lung of the ART groups. Our results indicate that ART increases long-term alterations in SCAP/SREBP expression that may be associated with their aberrant methylation status in mouse.
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Affiliation(s)
- Fang Le
- Center of Reproductive Medicine, Zhejiang University School of Medicine Women's Hospital, Hangzhou, China
| | - Ning Wang
- Center of Reproductive Medicine, Zhejiang University School of Medicine Women's Hospital, Hangzhou, China
| | - Qijing Wang
- Center of Reproductive Medicine, Zhejiang University School of Medicine Women's Hospital, Hangzhou, China
| | - Xinyun Yang
- Center of Reproductive Medicine, Zhejiang University School of Medicine Women's Hospital, Hangzhou, China
| | - Lejun Li
- Center of Reproductive Medicine, Zhejiang University School of Medicine Women's Hospital, Hangzhou, China
| | - Liya Wang
- Center of Reproductive Medicine, Zhejiang University School of Medicine Women's Hospital, Hangzhou, China
| | - Xiaozhen Liu
- Center of Reproductive Medicine, Zhejiang University School of Medicine Women's Hospital, Hangzhou, China
| | - Minhao Hu
- Center of Reproductive Medicine, Zhejiang University School of Medicine Women's Hospital, Hangzhou, China
| | - Fan Jin
- Center of Reproductive Medicine, Zhejiang University School of Medicine Women's Hospital, Hangzhou, China.,Key Laboratory of Reproductive Genetics, Ministry of Education, Hangzhou, China
| | - Hangying Lou
- Center of Reproductive Medicine, Zhejiang University School of Medicine Women's Hospital, Hangzhou, China
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7
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Hartleben G, Schorpp K, Kwon Y, Betz B, Tsokanos F, Dantes Z, Schäfer A, Rothenaigner I, Monroy Kuhn JM, Morigny P, Mehr L, Lin S, Seitz S, Tokarz J, Artati A, Adamsky J, Plettenburg O, Lutter D, Irmler M, Beckers J, Reichert M, Hadian K, Zeigerer A, Herzig S, Berriel Diaz M. Combination therapies induce cancer cell death through the integrated stress response and disturbed pyrimidine metabolism. EMBO Mol Med 2021; 13:e12461. [PMID: 33665961 PMCID: PMC8033521 DOI: 10.15252/emmm.202012461] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 01/24/2021] [Accepted: 01/27/2021] [Indexed: 01/05/2023] Open
Abstract
By accentuating drug efficacy and impeding resistance mechanisms, combinatorial, multi-agent therapies have emerged as key approaches in the treatment of complex diseases, most notably cancer. Using high-throughput drug screens, we uncovered distinct metabolic vulnerabilities and thereby identified drug combinations synergistically causing a starvation-like lethal catabolic response in tumor cells from different cancer entities. Domperidone, a dopamine receptor antagonist, as well as several tricyclic antidepressants (TCAs), including imipramine, induced cancer cell death in combination with the mitochondrial uncoupler niclosamide ethanolamine (NEN) through activation of the integrated stress response pathway and the catabolic CLEAR network. Using transcriptome and metabolome analyses, we characterized a combinatorial response, mainly driven by the transcription factors CHOP and TFE3, which resulted in cell death through enhanced pyrimidine catabolism as well as reduced pyrimidine synthesis. Remarkably, the drug combinations sensitized human organoid cultures to the standard-of-care chemotherapy paclitaxel. Thus, our combinatorial approach could be clinically implemented into established treatment regimen, which would be further facilitated by the advantages of drug repurposing.
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8
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Jo A, Kim M, Kim JI, Ha J, Hwang YS, Nam H, Hwang I, Kim JB, Park SB. Phenotypic Discovery of SB1501, an Anti-obesity Agent, through Modulating Mitochondrial Activity. ChemMedChem 2021; 16:1104-1115. [PMID: 33538065 DOI: 10.1002/cmdc.202100062] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Indexed: 11/08/2022]
Abstract
Obesity has become a pandemic that threatens the quality of life and discovering novel therapeutic agents that can reverse obesity and obesity-related metabolic disorders are necessary. Here, we aimed to identify new anti-obesity agents using a phenotype-based approach. We performed image-based high-content screening with a fluorogenic bioprobe (SF44), which visualizes cellular lipid droplets (LDs), to identify initial hit compounds. A structure-activity relationship study led us to yield a bioactive compound SB1501, which reduces cellular LDs in 3T3-L1 adipocytes without cytotoxicity. SB1501 induced the expression of gene products that regulate mitochondrial biogenesis and fatty acid oxidation in 3T3-L1 adipocytes. Daily treatment with SB1501 improved the metabolic states of db/db mice by reducing body fat mass, adipose tissue mass, food intake, and increasing glucose tolerance. The anti-obesity effect of SB1501 may result from perturbation of the PGC-1α-UCP1 regulatory axis in inguinal white adipose tissue and brown adipose tissue. These data suggest the therapeutic potential of SB1501 as an anti-obesity agent via modulating mitochondrial activities.
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Affiliation(s)
- Ala Jo
- CRI Center for Chemical Proteomics, Department of Chemistry, Seoul National University, Seoul, 08826, Korea
| | - Mingi Kim
- CRI Center for Chemical Proteomics, Department of Chemistry, Seoul National University, Seoul, 08826, Korea
| | - Jong In Kim
- CRI Center for Adipocyte Structure-Function, School of Biological Sciences, Seoul National University, Seoul, 08826, Korea
| | - Jaeyoung Ha
- Department of Biophysics and Chemical Biology, Seoul National University, Seoul, 08826, Korea
| | - Yoon Soo Hwang
- CRI Center for Chemical Proteomics, Department of Chemistry, Seoul National University, Seoul, 08826, Korea
| | - Hyunsung Nam
- CRI Center for Chemical Proteomics, Department of Chemistry, Seoul National University, Seoul, 08826, Korea
| | - Injae Hwang
- CRI Center for Adipocyte Structure-Function, School of Biological Sciences, Seoul National University, Seoul, 08826, Korea
| | - Jae Bum Kim
- CRI Center for Adipocyte Structure-Function, School of Biological Sciences, Seoul National University, Seoul, 08826, Korea
| | - Seung Bum Park
- CRI Center for Chemical Proteomics, Department of Chemistry, Seoul National University, Seoul, 08826, Korea.,Department of Biophysics and Chemical Biology, Seoul National University, Seoul, 08826, Korea
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9
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Hughes DT, Halliday M, Smith HL, Verity NC, Molloy C, Radford H, Butcher AJ, Mallucci GR. Targeting the kinase insert loop of PERK selectively modulates PERK signaling without systemic toxicity in mice. Sci Signal 2020; 13:13/644/eabb4749. [PMID: 32788341 DOI: 10.1126/scisignal.abb4749] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Chronic activation of the unfolded protein response (UPR), notably the branch comprising the kinase PERK and the translation initiation factor eIF2α, is a pathological feature of many neurodegenerative diseases caused by protein misfolding. Partial reduction of UPR signaling at the level of phosphorylated eIF2α is neuroprotective and avoids the pancreatic toxicity caused by full inhibition of PERK kinase activity. However, other stress pathways besides the UPR converge on phosphorylated eIF2α in the integrated stress response (ISR), which is critical to normal cellular function. We explored whether partial inhibition of PERK signaling may be a better therapeutic option. PERK-mediated phosphorylation of eIF2α requires its binding to the insert loop within PERK's kinase domain, which is, itself, phosphorylated at multiple sites. We found that, as expected, Akt mediates the phosphorylation of Thr799 in PERK. This phosphorylation event reduced eIF2α binding to PERK and selectively attenuated downstream signaling independently of PERK activity and the broader ISR. Induction of Thr799 phosphorylation with a small-molecule activator of Akt similarly reduced PERK signaling and increased both neuronal and animal survival without measurable pancreatic toxicity in a mouse model of prion disease. Thus, promoting PERK phosphorylation at Thr799 to partially down-regulate PERK-eIF2α signaling while avoiding widespread ISR inhibition may be a safe therapeutic approach in neurodegenerative disease.
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Affiliation(s)
- Daniel T Hughes
- Department of Clinical Neurosciences and UK Dementia Research Institute at the University of Cambridge, Island Research Building, Cambridge Biomedical Campus, Cambridge CB2 0AH, UK
| | - Mark Halliday
- Department of Clinical Neurosciences and UK Dementia Research Institute at the University of Cambridge, Island Research Building, Cambridge Biomedical Campus, Cambridge CB2 0AH, UK
| | - Heather L Smith
- Department of Clinical Neurosciences and UK Dementia Research Institute at the University of Cambridge, Island Research Building, Cambridge Biomedical Campus, Cambridge CB2 0AH, UK
| | - Nicholas C Verity
- MRC Toxicology Unit at the University of Cambridge, Hodgkin Building, Leicester LE1 7HB, UK
| | - Colin Molloy
- MRC Toxicology Unit at the University of Cambridge, Hodgkin Building, Leicester LE1 7HB, UK
| | - Helois Radford
- Department of Clinical Neurosciences and UK Dementia Research Institute at the University of Cambridge, Island Research Building, Cambridge Biomedical Campus, Cambridge CB2 0AH, UK
| | - Adrian J Butcher
- Department of Clinical Neurosciences and UK Dementia Research Institute at the University of Cambridge, Island Research Building, Cambridge Biomedical Campus, Cambridge CB2 0AH, UK
| | - Giovanna R Mallucci
- Department of Clinical Neurosciences and UK Dementia Research Institute at the University of Cambridge, Island Research Building, Cambridge Biomedical Campus, Cambridge CB2 0AH, UK.
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10
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Trimethylamine N-Oxide Binds and Activates PERK to Promote Metabolic Dysfunction. Cell Metab 2019; 30:1141-1151.e5. [PMID: 31543404 DOI: 10.1016/j.cmet.2019.08.021] [Citation(s) in RCA: 208] [Impact Index Per Article: 41.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 07/02/2019] [Accepted: 08/26/2019] [Indexed: 12/20/2022]
Abstract
The gut-microbe-derived metabolite trimethylamine N-oxide (TMAO) is increased by insulin resistance and associated with several sequelae of metabolic syndrome in humans, including cardiovascular, renal, and neurodegenerative disease. The mechanism by which TMAO promotes disease is unclear. We now reveal the endoplasmic reticulum stress kinase PERK (EIF2AK3) as a receptor for TMAO: TMAO binds to PERK at physiologically relevant concentrations; selectively activates the PERK branch of the unfolded protein response; and induces the transcription factor FoxO1, a key driver of metabolic disease, in a PERK-dependent manner. Furthermore, interventions to reduce TMAO, either by manipulation of the gut microbiota or by inhibition of the TMAO synthesizing enzyme, flavin-containing monooxygenase 3, can reduce PERK activation and FoxO1 levels in the liver. Taken together, these data suggest TMAO and PERK may be central to the pathogenesis of the metabolic syndrome.
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11
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ER Stress Activates the NLRP3 Inflammasome: A Novel Mechanism of Atherosclerosis. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:3462530. [PMID: 31687078 PMCID: PMC6800950 DOI: 10.1155/2019/3462530] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 08/21/2019] [Accepted: 08/31/2019] [Indexed: 02/06/2023]
Abstract
The endoplasmic reticulum (ER) is an important organelle that regulates several fundamental cellular processes, and ER dysfunction has implications for many intracellular events. The nucleotide-binding oligomerization domain-like receptor family, pyrin domain-containing 3 (NLRP3) inflammasome is an intracellularly produced macromolecular complex that can trigger pyroptosis and inflammation, and its activation is induced by a variety of signals. ER stress has been found to affect NLRP3 inflammasome activation through multiple effects including the unfolded protein response (UPR), calcium or lipid metabolism, and reactive oxygen species (ROS) generation. Intriguingly, the role of ER stress in inflammasome activation has not attracted a great deal of attention. In addition, increasing evidence highlights that both ER stress and NLRP3 inflammasome activation contribute to atherosclerosis (AS). AS is a common cardiovascular disease with complex pathogenesis, and the precise mechanisms behind its pathogenesis remain to be determined. Both ER stress and the NLRP3 inflammasome have emerged as critical individual contributors of AS, and owing to the multiple associations between these two events, we speculate that they contribute to the mechanisms of pathogenesis in AS. In this review, we aim to summarize the molecular mechanisms of ER stress, NLRP3 inflammasome activation, and the cross talk between these two pathways in AS in the hopes of providing new pharmacological targets for AS treatment.
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12
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Corton JC. Frequent Modulation of the Sterol Regulatory Element Binding Protein (SREBP) by Chemical Exposure in the Livers of Rats. ACTA ACUST UNITED AC 2019; 10:113-129. [PMID: 30931410 DOI: 10.1016/j.comtox.2019.01.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Inappropriate activation of sterol regulatory element-binding proteins (SREBPs) can lead to non-alcoholic fatty liver disease (NAFLD). To link chemical exposure to SREBP activity, a previously characterized gene expression biomarker (Rooney et al., 2019) was used to identify microarray comparisons from rat liver that exhibited significant positive or negative correlation to the biomarker. The effects of 620 chemicals on SREBP activity were examined across 9305 chemical-dose-time microarray comparisons. SREBP was found to be frequently modulated by chemical exposure with 54% of the chemicals affecting SREBP activity. Activators included inhibitors of cholesterogenesis that act to inhibit HMG-CoA reductase (statins) or inhibit Cyp51 (conazoles). Most chemical effects were transient, lasting usually no more than 2-4 days. Modulation of SREBP in most cases led to coordinated increases or decreases in lipogenic and cholesterogenic genes. However, 570 chemical exposure conditions were identified in which regulation was uncoupled. Most of these conditions affected cholesterogenic genes in the absence of parallel effects on lipogenic genes. Together, these findings show that SREBP is a frequent target of chemical exposure and expression of lipogenic and cholesterogenic genes can be uncoupled.
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Affiliation(s)
- J Christopher Corton
- Integrated Systems Toxicology Division, NHEERL/ORD, US-EPA, Research Triangle Park, NC 27711
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13
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Widespread PERK-dependent repression of ER targets in response to ER stress. Sci Rep 2019; 9:4330. [PMID: 30867432 PMCID: PMC6416471 DOI: 10.1038/s41598-019-38705-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 01/04/2019] [Indexed: 12/11/2022] Open
Abstract
The UPR (Unfolded Protein Response) is a well-orchestrated response to ER protein folding and processing overload, integrating both transcriptional and translational outputs. Its three arms in mammalian cells, the PERK translational response arm, together with the ATF6 and IRE1-XBP1-mediated transcriptional arms, have been thoroughly investigated. Using ribosome footprint profiling, we performed a deep characterization of gene expression programs involved in the early and late ER stress responses, within WT or PERK -/- Mouse Embryonic Fibroblasts (MEFs). We found that both repression and activation gene expression programs, affecting hundreds of genes, are significantly hampered in the absence of PERK. Specifically, PERK -/- cells do not show global translational inhibition, nor do they specifically activate early gene expression programs upon short exposure to ER stress. Furthermore, while PERK -/- cells do activate/repress late ER-stress response genes, the response is substantially weaker. Importantly, we highlight a widespread PERK-dependent repression program, consisting of ER targeted proteins, including transmembrane proteins, glycoproteins, and proteins with disulfide bonds. This phenomenon occurs in various different cell types, and has a major translational regulatory component. Moreover, we revealed a novel interplay between PERK and the XBP1-ATF6 arms of the UPR, whereby PERK attenuates the expression of a specific subset of XBP1-ATF6 targets, further illuminating the complexity of the integrated ER stress response.
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14
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Lu H, Sathe AA, Xing C, Lehrman MA. The Lec5 glycosylation mutant links homeobox genes with cholesterol and lipid-linked oligosaccharides. Glycobiology 2019; 29:106-109. [PMID: 30388226 PMCID: PMC6330018 DOI: 10.1093/glycob/cwy103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 11/01/2018] [Indexed: 11/12/2022] Open
Abstract
Discovered 40 years ago, the Lec5 glycosylation mutant cell line has a complex recessive genotype and is characterized by accumulation of lipid-linked oligosaccharide assembly intermediates, reduced conversion of polyprenols to dolichols, and an unusual phenotypic dependence upon cell culture conditions such as temperature, plating density and medium quality. The heritable defect in Lec5 is unknown. Here we demonstrate an unexpected epigenetic basis for Lec5, with a surprising linkage to increased expression of homeobox genes, which in turn is associated with increased transcription of cholesterol biosynthesis genes. These results suggest testable hypotheses for the biochemical abnormalities of the Lec5 mutant.
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Affiliation(s)
- Hua Lu
- Department of Pharmacology, UT Southwestern Medical Center, 6001 Forest Park Rd., Dallas, TX, USA
| | - Adwait Amod Sathe
- Eugene McDermott Center for Human Growth & Development, UT Southwestern Medical Center, 6001 Forest Park Rd., Dallas, TX, USA
| | - Chao Xing
- Eugene McDermott Center for Human Growth & Development, UT Southwestern Medical Center, 6001 Forest Park Rd., Dallas, TX, USA
- Department of Bioinformatics, UT Southwestern Medical Center, 6001 Forest Park Rd., Dallas, TX, USA
- Department of Clinical Sciences, UT Southwestern Medical Center, 6001 Forest Park Rd., Dallas, TX, USA
| | - Mark A Lehrman
- Department of Pharmacology, UT Southwestern Medical Center, 6001 Forest Park Rd., Dallas, TX, USA
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15
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Stojanovska V, Sharma N, Dijkstra DJ, Scherjon SA, Jäger A, Schorle H, Plösch T. Placental insufficiency contributes to fatty acid metabolism alterations in aged female mouse offspring. Am J Physiol Regul Integr Comp Physiol 2018; 315:R1107-R1114. [PMID: 30207754 DOI: 10.1152/ajpregu.00420.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Intrauterine growth restriction (IUGR) is an accepted risk factor for metabolic disorders in later life, including obesity and type 2 diabetes. The level of metabolic dysregulation can vary between subjects and is dependent on the severity and the type of IUGR insult. Classical IUGR animal models involve nutritional deprivation of the mother or uterine artery ligation. The latter aims to mimic a placental insufficiency, which is the most frequent cause of IUGR. In this study, we investigated whether IUGR attributable to placental insufficiency impacts the glucose and lipid homeostasis at advanced age. Placental insufficiency was achieved by deletion of the transcription factor AP-2y ( Tfap2c), which serves as one of the major trophoblast differentiation regulators. TdelT-IUGR mice were obtained by crossing mice with a floxed Tfap2c allele and mice with Cre recombinase under the control of the Tpbpa promoter. In advanced adulthood (9-12 mo), female and male IUGR mice are respectively 20% and 12% leaner compared with controls. At this age, IUGR mice have unaffected glucose clearance and lipid parameters (cholesterol, triglycerides, and phospholipids) in the liver. However, female IUGR mice have increased plasma free fatty acids (+87%) compared with controls. This is accompanied by increased mRNA levels of fatty acid synthase and endoplasmic reticulum stress markers in white adipose tissue. Taken together, our results suggest that IUGR by placental insufficiency may lead to higher lipogenesis in female mice in advanced adulthood, at least indicated by greater Fasn expression. This effect was sex specific for the aged IUGR females.
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Affiliation(s)
- Violeta Stojanovska
- Department of Obstetrics and Gynecology, University of Groningen, University Medical Center Groningen , Groningen , The Netherlands
| | - Neha Sharma
- Department of Developmental Pathology, Institute of Pathology, Bonn University Medical School , Bonn , Germany
| | - Dorieke J Dijkstra
- Department of Obstetrics and Gynecology, University of Groningen, University Medical Center Groningen , Groningen , The Netherlands
| | - Sicco A Scherjon
- Department of Obstetrics and Gynecology, University of Groningen, University Medical Center Groningen , Groningen , The Netherlands
| | - Andrea Jäger
- Department of Developmental Pathology, Institute of Pathology, Bonn University Medical School , Bonn , Germany
| | - Hubert Schorle
- Department of Developmental Pathology, Institute of Pathology, Bonn University Medical School , Bonn , Germany
| | - Torsten Plösch
- Department of Obstetrics and Gynecology, University of Groningen, University Medical Center Groningen , Groningen , The Netherlands
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16
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Chu J, Pelletier J. Therapeutic Opportunities in Eukaryotic Translation. Cold Spring Harb Perspect Biol 2018; 10:cshperspect.a032995. [PMID: 29440069 DOI: 10.1101/cshperspect.a032995] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The ability to block biological processes with selective small molecules provides advantages distinct from most other experimental approaches. These include rapid time to onset, swift reversibility, ability to probe activities in manners that cannot be accessed by genetic means, and the potential to be further developed as therapeutic agents. Small molecule inhibitors can also be used to alter expression and activity without affecting the stoichiometry of interacting partners. These tenets have been especially evident in the field of translation. Small molecule inhibitors were instrumental in enabling investigators to capture short-lived complexes and characterize specific steps of protein synthesis. In addition, several drugs that are the mainstay of modern antimicrobial drug therapy are potent inhibitors of prokaryotic translation. Currently, there is much interest in targeting eukaryotic translation as decades of research have revealed that deregulated protein synthesis in cancer cells represents a targetable vulnerability. In addition to being potential therapeutics, small molecules that manipulate translation have also been shown to influence cognitive processes such as memory. In this review, we focus on small molecule modulators that target the eukaryotic translation initiation apparatus and provide an update on their potential application to the treatment of disease.
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Affiliation(s)
- Jennifer Chu
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Jerry Pelletier
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada.,Department of Oncology, McGill University, Montreal, Quebec H3G 1Y6, Canada.,Rosalind and Morris Goodman Cancer Research Center, McGill University, Montreal, Quebec H3G 1Y6, Canada
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17
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Moon SL, Sonenberg N, Parker R. Neuronal Regulation of eIF2α Function in Health and Neurological Disorders. Trends Mol Med 2018; 24:575-589. [PMID: 29716790 DOI: 10.1016/j.molmed.2018.04.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 04/04/2018] [Accepted: 04/05/2018] [Indexed: 12/12/2022]
Abstract
A key site of translation control is the phosphorylation of the eukaryotic translation initiation factor 2α (eIF2α), which reduces the rate of GDP to GTP exchange by eIF2B, leading to altered translation. The extent of eIF2α phosphorylation within neurons can alter synaptic plasticity. Phosphorylation of eIF2α is triggered by four stress-responsive kinases, and as such eIF2α is often phosphorylated during neurological perturbations or disease. Moreover, in some cases decreasing eIF2α phosphorylation mitigates neurodegeneration, suggesting that this could be a therapeutic target. Mutations in the γ subunit of eIF2, the guanine exchange factor eIF2B, an eIF2α phosphatase, or in two eIF2α kinases can cause disease in humans, demonstrating the importance of proper regulation of eIF2α phosphorylation for health.
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Affiliation(s)
- Stephanie L Moon
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80303, USA
| | - Nahum Sonenberg
- Department of Biochemistry and Goodman Cancer Research Centre, McGill University, Montreal, QC H3A 1A3, Canada
| | - Roy Parker
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80303, USA; Howard Hughes Medical Institute, University of Colorado, Boulder, CO 80303, USA.
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18
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Tang X, Snowball JM, Xu Y, Na CL, Weaver TE, Clair G, Kyle JE, Zink EM, Ansong C, Wei W, Huang M, Lin X, Whitsett JA. EMC3 coordinates surfactant protein and lipid homeostasis required for respiration. J Clin Invest 2017; 127:4314-4325. [PMID: 29083321 DOI: 10.1172/jci94152] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 09/26/2017] [Indexed: 01/30/2023] Open
Abstract
Adaptation to respiration at birth depends upon the synthesis of pulmonary surfactant, a lipid-protein complex that reduces surface tension at the air-liquid interface in the alveoli and prevents lung collapse during the ventilatory cycle. Herein, we demonstrated that the gene encoding a subunit of the endoplasmic reticulum membrane complex, EMC3, also known as TMEM111 (Emc3/Tmem111), was required for murine pulmonary surfactant synthesis and lung function at birth. Conditional deletion of Emc3 in murine embryonic lung epithelial cells disrupted the synthesis and packaging of surfactant lipids and proteins, impaired the formation of lamellar bodies, and induced the unfolded protein response in alveolar type 2 (AT2) cells. EMC3 was essential for the processing and routing of surfactant proteins, SP-B and SP-C, and the biogenesis of the phospholipid transport protein ABCA3. Transcriptomic, lipidomic, and proteomic analyses demonstrated that EMC3 coordinates the assembly of lipids and proteins in AT2 cells that is necessary for surfactant synthesis and function at birth.
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Affiliation(s)
- Xiaofang Tang
- Divisions of Neonatology, Perinatal and Pulmonary Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - John M Snowball
- Divisions of Neonatology, Perinatal and Pulmonary Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Yan Xu
- Divisions of Neonatology, Perinatal and Pulmonary Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Cheng-Lun Na
- Divisions of Neonatology, Perinatal and Pulmonary Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Timothy E Weaver
- Divisions of Neonatology, Perinatal and Pulmonary Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Geremy Clair
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Jennifer E Kyle
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Erika M Zink
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Charles Ansong
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Wei Wei
- State Key Laboratory of Genetic Engineering, Institute of Genetics, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China
| | - Meina Huang
- State Key Laboratory of Genetic Engineering, Institute of Genetics, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China
| | - Xinhua Lin
- State Key Laboratory of Genetic Engineering, Institute of Genetics, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China.,Division of Developmental Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Jeffrey A Whitsett
- Divisions of Neonatology, Perinatal and Pulmonary Biology, Perinatal Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
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19
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Halliday M, Radford H, Zents KAM, Molloy C, Moreno JA, Verity NC, Smith E, Ortori CA, Barrett DA, Bushell M, Mallucci GR. Repurposed drugs targeting eIF2α-P-mediated translational repression prevent neurodegeneration in mice. Brain 2017; 140:1768-1783. [PMID: 28430857 PMCID: PMC5445255 DOI: 10.1093/brain/awx074] [Citation(s) in RCA: 205] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 12/21/2016] [Accepted: 01/31/2017] [Indexed: 01/06/2023] Open
Abstract
See Mercado and Hetz (doi:10.1093/brain/awx107) for a scientific commentary on this article.Signalling through the PERK/eIF2α-P branch of the unfolded protein response plays a critical role in controlling protein synthesis rates in cells. This pathway is overactivated in brains of patients with Alzheimer’s disease and related disorders and has recently emerged as a promising therapeutic target for these currently untreatable conditions. Thus, in mouse models of neurodegenerative disease, prolonged overactivation of PERK/eIF2α-P signalling causes sustained attenuation of protein synthesis, leading to memory impairment and neuronal loss. Re-establishing translation rates by inhibition of eIF2α-P activity, genetically or pharmacologically, restores memory and prevents neurodegeneration and extends survival. However, the experimental compounds used preclinically are unsuitable for use in humans, due to associated toxicity or poor pharmacokinetic properties. To discover compounds that have anti-eIF2α-P activity suitable for clinical use, we performed phenotypic screens on a NINDS small molecule library of 1040 drugs. We identified two compounds, trazodone hydrochloride and dibenzoylmethane, which reversed eIF2α-P-mediated translational attenuation in vitro and in vivo. Both drugs were markedly neuroprotective in two mouse models of neurodegeneration, using clinically relevant doses over a prolonged period of time, without systemic toxicity. Thus, in prion-diseased mice, both trazodone and dibenzoylmethane treatment restored memory deficits, abrogated development of neurological signs, prevented neurodegeneration and significantly prolonged survival. In tauopathy-frontotemporal dementia mice, both drugs were neuroprotective, rescued memory deficits and reduced hippocampal atrophy. Further, trazodone reduced p-tau burden. These compounds therefore represent potential new disease-modifying treatments for dementia. Trazodone in particular, a licensed drug, should now be tested in clinical trials in patients.
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Affiliation(s)
- Mark Halliday
- MRC Toxicology Unit, Hodgkin Building, Lancaster Road, Leicester LE1 9HN, UK
| | - Helois Radford
- MRC Toxicology Unit, Hodgkin Building, Lancaster Road, Leicester LE1 9HN, UK
| | - Karlijn A M Zents
- Department of Clinical Neurosciences, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0AH, UK
| | - Collin Molloy
- MRC Toxicology Unit, Hodgkin Building, Lancaster Road, Leicester LE1 9HN, UK
| | - Julie A Moreno
- MRC Toxicology Unit, Hodgkin Building, Lancaster Road, Leicester LE1 9HN, UK
| | - Nicholas C Verity
- MRC Toxicology Unit, Hodgkin Building, Lancaster Road, Leicester LE1 9HN, UK
| | - Ewan Smith
- MRC Toxicology Unit, Hodgkin Building, Lancaster Road, Leicester LE1 9HN, UK
| | - Catharine A Ortori
- Centre for Analytical Bioscience, School of Pharmacy, University of Nottingham, Nottingham NG7 2RD, UK
| | - David A Barrett
- Centre for Analytical Bioscience, School of Pharmacy, University of Nottingham, Nottingham NG7 2RD, UK
| | - Martin Bushell
- MRC Toxicology Unit, Hodgkin Building, Lancaster Road, Leicester LE1 9HN, UK
| | - Giovanna R Mallucci
- MRC Toxicology Unit, Hodgkin Building, Lancaster Road, Leicester LE1 9HN, UK
- Department of Clinical Neurosciences, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0AH, UK
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20
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Doultsinos D, Avril T, Lhomond S, Dejeans N, Guédat P, Chevet E. Control of the Unfolded Protein Response in Health and Disease. SLAS DISCOVERY 2017; 22:787-800. [PMID: 28453376 DOI: 10.1177/2472555217701685] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The unfolded protein response (UPR) is an integrated, adaptive biochemical process that is inextricably linked with cell homeostasis and paramount to maintenance of normal physiological function. Prolonged accumulation of improperly folded proteins in the endoplasmic reticulum (ER) leads to stress. This is the driving stimulus behind the UPR. As such, prolonged ER stress can push the UPR past beneficial functions such as reduced protein production and increased folding and clearance to apoptotic signaling. The UPR is thus contributory to the commencement, maintenance, and exacerbation of a multitude of disease states, making it an attractive global target to tackle conditions sorely in need of novel therapeutic intervention. The accumulation of information of screening tools, readily available therapies, and potential pathways to drug development is the cornerstone of informed clinical research and clinical trial design. Here, we review the UPR's involvement in health and disease and, beyond providing an in-depth description of the molecules found to target the three UPR arms, we compile all the tools available to screen for and develop novel therapeutic agents that modulate the UPR with the scope of future disease intervention.
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Affiliation(s)
- Dimitrios Doultsinos
- 1 Inserm U1242, Chemistry, Oncogenesis, Stress & Signaling, University of Rennes 1, Rennes, France.,2 Centre de Lutte contre le Cancer Eugène Marquis, Rennes, France
| | - Tony Avril
- 1 Inserm U1242, Chemistry, Oncogenesis, Stress & Signaling, University of Rennes 1, Rennes, France.,2 Centre de Lutte contre le Cancer Eugène Marquis, Rennes, France
| | | | | | | | - Eric Chevet
- 1 Inserm U1242, Chemistry, Oncogenesis, Stress & Signaling, University of Rennes 1, Rennes, France.,2 Centre de Lutte contre le Cancer Eugène Marquis, Rennes, France.,3 BMYscreen, Bergonié Cancer Institute, Bordeaux, France
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21
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Duan H, Lee JW, Moon SW, Arora D, Li Y, Lim HY, Wang W. Discovery, Synthesis, and Evaluation of 2,4-Diaminoquinazolines as a Novel Class of Pancreatic β-Cell-Protective Agents against Endoplasmic Reticulum (ER) Stress. J Med Chem 2016; 59:7783-800. [PMID: 27505441 DOI: 10.1021/acs.jmedchem.6b00041] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Pancreatic insulin-producing β-cell dysfunction and death plays central roles in the onset and progression of both type 1 and type 2 diabetes. Current antidiabetic drugs cannot halt the ongoing progression of β-cell dysfunction and death. In diabetes, a major cause for the decline in β-cell function and survival is endoplasmic reticulum (ER) stress. Here, we identified quinazoline derivatives as a novel class of β-cell protective agents against ER stress-induced dysfunction and death. A series of quinazoline derivatives were synthesized from dichloroquiazoline utilizing a sequence of nucleophilic reactions. Through SAR optimization, 2,4-diaminoquinazoline compound 9c markedly protects β-cells against ER stress-induced dysfunction and death with 80% maximum rescue activity and an EC50 value of 0.56 μM. Importantly, 9c restores the ER stress-impaired glucose-stimulated insulin secretion response and survival in primary human islet β-cells. We showed that 9c protects β-cells by alleviating ER stress through the suppression of the induction of key genes of the unfolded protein response and apoptosis.
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Affiliation(s)
- Hongliang Duan
- Immunobiology and Cancer Program, Oklahoma Medical Research Foundation , 825 NE 13th Street, Oklahoma City, Oklahoma 73104, United States
| | - Jae Wook Lee
- Natural Product Research Center, Korea Institute of Science and Technology , 679 Saimdang-ro, Gangneung, Gangwon-do 210-340, Republic of Korea.,Department of Biological Chemistry, Korea University of Science and Technology (UST) , Daejeon 305-333, Republic of Korea
| | - Sung Won Moon
- Natural Product Research Center, Korea Institute of Science and Technology , 679 Saimdang-ro, Gangneung, Gangwon-do 210-340, Republic of Korea
| | - Daleep Arora
- Immunobiology and Cancer Program, Oklahoma Medical Research Foundation , 825 NE 13th Street, Oklahoma City, Oklahoma 73104, United States
| | - Yu Li
- Department of Medicine, Division of Endocrinology, Department of Physiology, Harold Hamm Diabetes Center, The University of Oklahoma Health Science Center , 941 Stanton L. Young Boulevard, Oklahoma City, Oklahoma 73104, United States
| | - Hui-Ying Lim
- Department of Physiology, The University of Oklahoma Health Science Center , 941 Stanton L. Young Boulevard, Oklahoma City, Oklahoma 73104, United States
| | - Weidong Wang
- Immunobiology and Cancer Program, Oklahoma Medical Research Foundation , 825 NE 13th Street, Oklahoma City, Oklahoma 73104, United States.,Department of Medicine, Division of Endocrinology, Department of Physiology, Harold Hamm Diabetes Center, The University of Oklahoma Health Science Center , 941 Stanton L. Young Boulevard, Oklahoma City, Oklahoma 73104, United States
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22
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Munshi S, Dahl R. Cytoprotective small molecule modulators of endoplasmic reticulum stress. Bioorg Med Chem 2016; 24:2382-2388. [PMID: 27091069 DOI: 10.1016/j.bmc.2016.03.045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Revised: 03/21/2016] [Accepted: 03/27/2016] [Indexed: 01/03/2023]
Abstract
Cellular health depends on the normal function of the endoplasmic reticulum (ER) to fold, assemble, and modify critical proteins to maintain viability. When the ER cannot process proteins effectively, a condition known as ER stress ensues. When this stress is excessive or prolonged, cell death via apoptotic pathways is triggered. Interestingly, most major diseases have been shown to be intimately linked to ER stress, including diabetes, stroke, neurodegeneration, and many cancers. Thus, controlling ER stress presents a significant strategy for drug development for these diseases. The goal of this review is to present various small molecules that alleviate ER stress with the intention that they may serve as useful starting points for therapeutic agent development.
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Affiliation(s)
- Soumyabrata Munshi
- Department of Neuroscience, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064, USA
| | - Russell Dahl
- Neurodon LLC, 5700 Tanager St., Schererville, IN 46375, USA.
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23
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Duan H, Li Y, Lim HY, Wang W. Identification of 5-nitrofuran-2-amide derivatives that induce apoptosis in triple negative breast cancer cells by activating C/EBP-homologous protein expression. Bioorg Med Chem 2015; 23:4514-4521. [PMID: 26116180 DOI: 10.1016/j.bmc.2015.06.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 05/27/2015] [Accepted: 06/04/2015] [Indexed: 12/22/2022]
Abstract
The transcription factor C/EBP-homologous protein (CHOP) is a key component of the terminal unfolded protein response (UPR) that mediates unresolvable endoplasmic reticulum stress-induced apoptosis. CHOP induction is known to cause cancer cell death. Chemicals that induce CHOP expression would thus be valuable as potential cancer therapeutics and as research tools. Here, we identified 5-nitrofuran-2-amide derivatives as small molecule activators of CHOP expression that induced apoptosis in triple negative breast cancer (TNBC) cells. Our preliminary structure-activity relationship studies indicated that compounds with an N-phenyl-5-nitrofuran-2-carboxamide skeleton were particularly potent inducers of TNBC cell apoptosis. The compounds activate CHOP expression via the PERK-eIF2α-ATF4 branch of the UPR. These results indicate that small molecule activators of CHOP expression may have therapeutic potential for TNBC.
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Affiliation(s)
- Hongliang Duan
- Immunobiology and Cancer Research Program, Oklahoma Medical Research Foundation, OK, USA
| | - Yu Li
- Immunobiology and Cancer Research Program, Oklahoma Medical Research Foundation, OK, USA
| | - Hui-Ying Lim
- Free Radical Biology and Aging Program, Oklahoma Medical Research Foundation, OK, USA
| | - Weidong Wang
- Immunobiology and Cancer Research Program, Oklahoma Medical Research Foundation, OK, USA.
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24
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Valdés A, Sullini G, Ibáñez E, Cifuentes A, García-Cañas V. Rosemary polyphenols induce unfolded protein response and changes in cholesterol metabolism in colon cancer cells. J Funct Foods 2015. [DOI: 10.1016/j.jff.2015.03.043] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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25
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Lorbek G, Perše M, Jeruc J, Juvan P, Gutierrez-Mariscal FM, Lewinska M, Gebhardt R, Keber R, Horvat S, Björkhem I, Rozman D. Lessons from hepatocyte-specific Cyp51 knockout mice: impaired cholesterol synthesis leads to oval cell-driven liver injury. Sci Rep 2015; 5:8777. [PMID: 25739789 PMCID: PMC4350092 DOI: 10.1038/srep08777] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 02/02/2015] [Indexed: 12/22/2022] Open
Abstract
We demonstrate unequivocally that defective cholesterol synthesis is an independent determinant of liver inflammation and fibrosis. We prepared a mouse hepatocyte-specific knockout (LKO) of lanosterol 14α-demethylase (CYP51) from the part of cholesterol synthesis that is already committed to cholesterol. LKO mice developed hepatomegaly with oval cell proliferation, fibrosis and inflammation, but without steatosis. The key trigger was reduced cholesterol esters that provoked cell cycle arrest, senescence-associated secretory phenotype and ultimately the oval cell response, while elevated CYP51 substrates promoted the integrated stress response. In spite of the oval cell-driven fibrosis being histologically similar in both sexes, data indicates a female-biased down-regulation of primary metabolism pathways and a stronger immune response in males. Liver injury was ameliorated by dietary fats predominantly in females, whereas dietary cholesterol rectified fibrosis in both sexes. Our data place defective cholesterol synthesis as a focus of sex-dependent liver pathologies.
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Affiliation(s)
- Gregor Lorbek
- Centre for Functional Genomics and Bio-Chips, Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Martina Perše
- Medical Experimental Centre, Institute of Pathology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Jera Jeruc
- Institute of Pathology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Peter Juvan
- Centre for Functional Genomics and Bio-Chips, Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Francisco M Gutierrez-Mariscal
- Centre for Functional Genomics and Bio-Chips, Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Monika Lewinska
- Centre for Functional Genomics and Bio-Chips, Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Rolf Gebhardt
- Institute of Biochemistry, Faculty of Medicine, University of Leipzig, Leipzig, Germany
| | - Rok Keber
- Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Simon Horvat
- 1] Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia [2] National Institute of Chemistry, Ljubljana, Slovenia
| | - Ingemar Björkhem
- Department of Laboratory Medicine, Division of Clinical Chemistry, Karolinska Institute, Karolinska University Hospital, Huddinge, Sweden
| | - Damjana Rozman
- Centre for Functional Genomics and Bio-Chips, Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
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26
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Halliday M, Radford H, Sekine Y, Moreno J, Verity N, le Quesne J, Ortori CA, Barrett DA, Fromont C, Fischer PM, Harding HP, Ron D, Mallucci GR. Partial restoration of protein synthesis rates by the small molecule ISRIB prevents neurodegeneration without pancreatic toxicity. Cell Death Dis 2015; 6:e1672. [PMID: 25741597 PMCID: PMC4385927 DOI: 10.1038/cddis.2015.49] [Citation(s) in RCA: 230] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 01/19/2015] [Indexed: 01/28/2023]
Abstract
Activation of the PERK branch of the unfolded protein response (UPR) in response to protein misfolding within the endoplasmic reticulum (ER) results in the transient repression of protein synthesis, mediated by the phosphorylation of the alpha subunit of eukaryotic initiation factor 2 (eIF2α). This is part of a wider integrated physiological response to maintain proteostasis in the face of ER stress, the dysregulation of which is increasingly associated with a wide range of diseases, particularly neurodegenerative disorders. In prion-diseased mice, persistently high levels of eIF2α cause sustained translational repression leading to catastrophic reduction of critical proteins, resulting in synaptic failure and neuronal loss. We previously showed that restoration of global protein synthesis using the PERK inhibitor GSK2606414 was profoundly neuroprotective, preventing clinical disease in prion-infected mice. However, this occured at the cost of toxicity to secretory tissue, where UPR activation is essential to healthy functioning. Here we show that pharmacological modulation of eIF2α-P-mediated translational inhibition can be achieved to produce neuroprotection without pancreatic toxicity. We found that treatment with the small molecule ISRIB, which restores translation downstream of eIF2α, conferred neuroprotection in prion-diseased mice without adverse effects on the pancreas. Critically, ISRIB treatment resulted in only partial restoration of global translation rates, as compared with the complete restoration of protein synthesis seen with GSK2606414. ISRIB likely provides sufficient rates of protein synthesis for neuronal survival, while allowing some residual protective UPR function in secretory tissue. Thus, fine-tuning the extent of UPR inhibition and subsequent translational de-repression uncouples neuroprotective effects from pancreatic toxicity. The data support the pursuit of this approach to develop new treatments for a range of neurodegenerative disorders that are currently incurable.
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Affiliation(s)
- M Halliday
- Medical Research Council Toxicology Unit, Hodgkin Building, University of Leicester, Leicester, UK
| | - H Radford
- Medical Research Council Toxicology Unit, Hodgkin Building, University of Leicester, Leicester, UK
| | - Y Sekine
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - J Moreno
- Medical Research Council Toxicology Unit, Hodgkin Building, University of Leicester, Leicester, UK
| | - N Verity
- Medical Research Council Toxicology Unit, Hodgkin Building, University of Leicester, Leicester, UK
| | - J le Quesne
- 1] Medical Research Council Toxicology Unit, Hodgkin Building, University of Leicester, Leicester, UK [2] Department of Histopathology, University Hospitals of Leicester NHS Trust, Leicester, UK
| | - C A Ortori
- Centre for Analytical Bioscience, School of Pharmacy, University of Nottingham, Nottingham, UK
| | - D A Barrett
- Centre for Analytical Bioscience, School of Pharmacy, University of Nottingham, Nottingham, UK
| | - C Fromont
- Division of Medicinal Chemistry & Structural Biology, School of Pharmacy, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, UK
| | - P M Fischer
- Division of Medicinal Chemistry & Structural Biology, School of Pharmacy, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, UK
| | - H P Harding
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - D Ron
- 1] Cambridge Institute for Medical Research, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK [2] The Wellcome Trust MRC Institute of Metabolic Science and NIHR Cambridge Biomedical Research Centre, Cambridge, UK
| | - G R Mallucci
- 1] Medical Research Council Toxicology Unit, Hodgkin Building, University of Leicester, Leicester, UK [2] Department of Clinical Neurosciences, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK
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27
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Flaherty DP, Miller JR, Garshott DM, Hedrick M, Gosalia P, Li Y, Milewski M, Sugarman E, Vasile S, Salaniwal S, Su Y, Smith LH, Chung TDY, Pinkerton AB, Aubé J, Callaghan MU, Golden JE, Fribley AM, Kaufman RJ. Discovery of Sulfonamidebenzamides as Selective Apoptotic CHOP Pathway Activators of the Unfolded Protein Response. ACS Med Chem Lett 2014; 5:1278-1283. [PMID: 25530830 PMCID: PMC4266338 DOI: 10.1021/ml5003234] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 10/29/2014] [Indexed: 01/29/2023] Open
Abstract
![]()
Cellular proteins that fail to fold
properly result in inactive
or disfunctional proteins that can have toxic functions. The unfolded
protein response (UPR) is a two-tiered cellular mechanism initiated
by eukaryotic cells that have accumulated misfolded proteins within
the endoplasmic reticulum (ER). An adaptive pathway facilitates the
clearance of the undesired proteins; however, if overwhelmed, cells
trigger apoptosis by upregulating transcription factors such as C/EBP-homologous
protein (CHOP). A high throughput screen was performed directed at
identifying compounds that selectively upregulate the apoptotic CHOP
pathway while avoiding adaptive signaling cascades, resulting in a
sulfonamidebenzamide chemotype that was optimized. These efforts produced
a potent and selective CHOP inducer (AC50 = 0.8 μM;
XBP1 > 80 μM), which was efficacious in both mouse embryonic
fibroblast cells and a human oral squamous cell cancer cell line,
and demonstrated antiproliferative effects for multiple cancer cell
lines in the NCI-60 panel.
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Affiliation(s)
- Daniel P. Flaherty
- Delbert
M. Shankel Structural Biology Center, University of Kansas Specialized Chemistry Center, 2034 Becker Drive, Lawrence, Kansas 66047, United States
| | - Justin R. Miller
- Carmen
and Ann Adams Department of Pediatrics, Division of Hematology and
Oncology, and the Karmanos Cancer Institute Molecular Therapeutics
Group, Wayne State University, 2228 Elliman Building, 421 East
Canfield, Detroit, Michigan 48201, United States
| | - Danielle M. Garshott
- Carmen
and Ann Adams Department of Pediatrics, Division of Hematology and
Oncology, and the Karmanos Cancer Institute Molecular Therapeutics
Group, Wayne State University, 2228 Elliman Building, 421 East
Canfield, Detroit, Michigan 48201, United States
| | - Michael Hedrick
- Conrad
Prebys Center for Chemical Genomics, Sanford-Burnham Medical Research Institute, La
Jolla, California 92037, United States
| | - Palak Gosalia
- Conrad
Prebys Center for Chemical Genomics, Sanford-Burnham Medical Research Institute, La
Jolla, California 92037, United States
| | - Yujie Li
- Conrad
Prebys Center for Chemical Genomics, Sanford-Burnham Medical Research Institute, La
Jolla, California 92037, United States
| | - Monika Milewski
- Conrad
Prebys Center for Chemical Genomics, Sanford-Burnham Medical Research Institute, La
Jolla, California 92037, United States
| | - Eliot Sugarman
- Conrad
Prebys Center for Chemical Genomics, Sanford-Burnham Medical Research Institute at Lake Nona, Orlando, Florida 32827, United States
| | - Stefan Vasile
- Conrad
Prebys Center for Chemical Genomics, Sanford-Burnham Medical Research Institute at Lake Nona, Orlando, Florida 32827, United States
| | - Sumeet Salaniwal
- Conrad
Prebys Center for Chemical Genomics, Sanford-Burnham Medical Research Institute, La
Jolla, California 92037, United States
| | - Ying Su
- Conrad
Prebys Center for Chemical Genomics, Sanford-Burnham Medical Research Institute, La
Jolla, California 92037, United States
| | - Layton H. Smith
- Conrad
Prebys Center for Chemical Genomics, Sanford-Burnham Medical Research Institute at Lake Nona, Orlando, Florida 32827, United States
| | - Thomas D. Y. Chung
- Conrad
Prebys Center for Chemical Genomics, Sanford-Burnham Medical Research Institute, La
Jolla, California 92037, United States
| | - Anthony B. Pinkerton
- Conrad
Prebys Center for Chemical Genomics, Sanford-Burnham Medical Research Institute, La
Jolla, California 92037, United States
| | - Jeffrey Aubé
- Delbert
M. Shankel Structural Biology Center, University of Kansas Specialized Chemistry Center, 2034 Becker Drive, Lawrence, Kansas 66047, United States
| | - Michael U. Callaghan
- Carmen
and Ann Adams Department of Pediatrics, Division of Hematology and
Oncology, and the Karmanos Cancer Institute Molecular Therapeutics
Group, Wayne State University, 2228 Elliman Building, 421 East
Canfield, Detroit, Michigan 48201, United States
| | - Jennifer E. Golden
- Delbert
M. Shankel Structural Biology Center, University of Kansas Specialized Chemistry Center, 2034 Becker Drive, Lawrence, Kansas 66047, United States
| | - Andrew M. Fribley
- Carmen
and Ann Adams Department of Pediatrics, Division of Hematology and
Oncology, and the Karmanos Cancer Institute Molecular Therapeutics
Group, Wayne State University, 2228 Elliman Building, 421 East
Canfield, Detroit, Michigan 48201, United States
| | - Randal J. Kaufman
- Program
in Degenerative Disease Research, Sanford-Burnham Medical Research Institute, 10901 North Torrey Pines Road, La Jolla, California 92037, United States
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28
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Su D, Oh J, Lee SC, Lim JM, Sahu S, Yu X, Kim D, Chang YT. Dark to light! A new strategy for large Stokes shift dyes: coupling of a dark donor with tunable high quantum yield acceptors. Chem Sci 2014. [DOI: 10.1039/c4sc01821d] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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29
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Cholesterol biosynthesis and ER stress in peroxisome deficiency. Biochimie 2014; 98:75-85. [DOI: 10.1016/j.biochi.2013.10.019] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 10/22/2013] [Indexed: 12/27/2022]
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30
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Ambrose RL, Mackenzie JM. Flaviviral regulation of the unfolded protein response: can stress be beneficial? Future Virol 2013. [DOI: 10.2217/fvl.13.100] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Members of the Flaviviridae family remain some of the most significant human viral pathogens, with few vaccines or antivirals commercially available for therapeutic use. Thus, understanding the intracellular events of replication and how these viruses modulate signaling within an infected cell is of great importance. The ER is central to replication within the Flaviviridae family, as the site of viral protein translation and processing, as a source of membranes for replication complex formation and as a site of virus assembly. This places a large burden upon the organelle, resulting in the induction of ER stress responses, in particular the unfolded protein response. In turn, unfolded protein response signaling induced in infected cells is tightly modulated by the virus in order to maintain an optimal environment for replication. The loss of various components of the stress response can have either beneficial or detrimental effects, presenting intriguing targets for antiviral discovery.
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Affiliation(s)
- Rebecca L Ambrose
- Department of Microbiology & Immunology, University of Melbourne, Parkville, Melbourne, VIC, 3052, Australia
| | - Jason M Mackenzie
- Department of Microbiology & Immunology, University of Melbourne, Parkville, Melbourne, VIC, 3052, Australia
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31
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Joshi M, Kulkarni A, Pal JK. Small molecule modulators of eukaryotic initiation factor 2α kinases, the key regulators of protein synthesis. Biochimie 2013; 95:1980-90. [PMID: 23939221 DOI: 10.1016/j.biochi.2013.07.030] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 07/26/2013] [Indexed: 01/25/2023]
Abstract
Eukaryotic initiation factor 2 alpha kinases (eIF-2α kinases) are key mediators of stress response in cells. In mammalian cells, there are four eIF-2α kinases, namely HRI (Heme-Regulated Inhibitor), PKR (RNA-dependent Protein Kinase), PERK (PKR-like ER Kinase) and GCN2 (General Control Non-derepressible 2). These kinases get activated during diverse cytoplasmic stress conditions and phosphorylate the alpha-subunit of eIF2, leading to global protein synthesis inhibition. Therefore, eIF-2α kinases play a vital role in various cellular processes such as proliferation, differentiation, apoptosis and cell signaling. Deregulation of eIF-2α kinases and protein synthesis has been linked to numerous pathological conditions such as certain cancers, anemia and neurodegenerative disorders. Thus, modulation of these kinases by small molecules holds a great therapeutic promise. In this review we have compiled the available information on inhibitors and activators of these four eIF-2α kinases. The review concludes with a note on the selectivity issue of currently available modulators and future perspectives for the design of specific small molecule probes.
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Affiliation(s)
- Manali Joshi
- Bioinformatics Center, University of Pune, Pune - 411007, Maharashtra, India.
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32
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The role of the unfolded protein response in diabetes mellitus. Semin Immunopathol 2013; 35:333-50. [PMID: 23529219 DOI: 10.1007/s00281-013-0369-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 03/13/2013] [Indexed: 12/13/2022]
Abstract
The endoplasmic reticulum (ER) plays a key role in the synthesis and modification of secretory and membrane proteins in all eukaryotic cells. Under normal conditions, these proteins are correctly folded and assembled in the ER. However, when cells are exposed to environmental factors such as overproduction of ER proteins, viral infections, or glucose deprivation, the secretory and membrane proteins can accumulate in unfolded or misfolded forms in the lumen of the ER, and consequently, cause stress in the ER. To maintain cellular homeostasis, cells induce several responses to ER stress. In mammalian cells, ER stress responses are induced by a diversity of signal pathways. There are three ER-located transmembrane proteins that play important roles in mammalian ER stress responses: activating transcription factor 6, inositol-requiring protein 1, and protein kinase RNA-like endoplasmic reticulum kinase. ER stress is linked to various diseases, including diabetes. This review highlights the particular importance of ER stress-responsive molecules in insulin biosynthesis, glyconeogenesis, insulin resistance, glucose intolerance, and pancreatic β-cell apoptosis. An understanding of the pathogenic mechanism of diabetes from the aspect of ER stress is crucial in formulating therapeutic strategies.
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33
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Viader A, Sasaki Y, Kim S, Strickland A, Workman CS, Yang K, Gross RW, Milbrandt J. Aberrant Schwann cell lipid metabolism linked to mitochondrial deficits leads to axon degeneration and neuropathy. Neuron 2013; 77:886-98. [PMID: 23473319 PMCID: PMC3594792 DOI: 10.1016/j.neuron.2013.01.012] [Citation(s) in RCA: 182] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/11/2013] [Indexed: 02/06/2023]
Abstract
Mitochondrial dysfunction is a common cause of peripheral neuropathy. Much effort has been devoted to examining the role played by neuronal/axonal mitochondria, but how mitochondrial deficits in peripheral nerve glia (Schwann cells [SCs]) contribute to peripheral nerve diseases remains unclear. Here, we investigate a mouse model of peripheral neuropathy secondary to SC mitochondrial dysfunction (Tfam-SCKOs). We show that disruption of SC mitochondria activates a maladaptive integrated stress response (ISR) through the actions of heme-regulated inhibitor (HRI) kinase, and causes a shift in lipid metabolism away from fatty acid synthesis toward oxidation. These alterations in SC lipid metabolism result in depletion of important myelin lipid components as well as in accumulation of acylcarnitines (ACs), an intermediate of fatty acid β-oxidation. Importantly, we show that ACs are released from SCs and induce axonal degeneration. A maladaptive ISR as well as altered SC lipid metabolism are thus underlying pathological mechanisms in mitochondria-related peripheral neuropathies.
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Affiliation(s)
- Andreu Viader
- Department of Genetics, Washington University School of Medicine, St. Louis, MO
| | - Yo Sasaki
- Department of Genetics, Washington University School of Medicine, St. Louis, MO
| | - Sungsu Kim
- Department of Genetics, Washington University School of Medicine, St. Louis, MO
| | - Amy Strickland
- Department of Genetics, Washington University School of Medicine, St. Louis, MO
| | - Cayce S. Workman
- Department of Genetics, Washington University School of Medicine, St. Louis, MO
| | - Kui Yang
- Division of Bioorganic Chemistry and Molecular Pharmacology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO
| | - Richard W. Gross
- Division of Bioorganic Chemistry and Molecular Pharmacology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO
| | - Jeffrey Milbrandt
- Department of Genetics, Washington University School of Medicine, St. Louis, MO
- Hope Center for Neurological Diseases, Washington University School of Medicine, St. Louis, MO
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34
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Griffiths B, Lewis CA, Bensaad K, Ros S, Zhang Q, Ferber EC, Konisti S, Peck B, Miess H, East P, Wakelam M, Harris AL, Schulze A. Sterol regulatory element binding protein-dependent regulation of lipid synthesis supports cell survival and tumor growth. Cancer Metab 2013; 1:3. [PMID: 24280005 PMCID: PMC3835903 DOI: 10.1186/2049-3002-1-3] [Citation(s) in RCA: 194] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 10/12/2012] [Indexed: 12/28/2022] Open
Abstract
Background Regulation of lipid metabolism via activation of sterol regulatory element binding proteins (SREBPs) has emerged as an important function of the Akt/mTORC1 signaling axis. Although the contribution of dysregulated Akt/mTORC1 signaling to cancer has been investigated extensively and altered lipid metabolism is observed in many tumors, the exact role of SREBPs in the control of biosynthetic processes required for Akt-dependent cell growth and their contribution to tumorigenesis remains unclear. Results We first investigated the effects of loss of SREBP function in non-transformed cells. Combined ablation of SREBP1 and SREBP2 by siRNA-mediated gene silencing or chemical inhibition of SREBP activation induced endoplasmic reticulum (ER)-stress and engaged the unfolded protein response (UPR) pathway, specifically under lipoprotein-deplete conditions in human retinal pigment epithelial cells. Induction of ER-stress led to inhibition of protein synthesis through increased phosphorylation of eIF2α. This demonstrates for the first time the importance of SREBP in the coordination of lipid and protein biosynthesis, two processes that are essential for cell growth and proliferation. SREBP ablation caused major changes in lipid composition characterized by a loss of mono- and poly-unsaturated lipids and induced accumulation of reactive oxygen species (ROS) and apoptosis. Alterations in lipid composition and increased ROS levels, rather than overall changes to lipid synthesis rate, were required for ER-stress induction. Next, we analyzed the effect of SREBP ablation in a panel of cancer cell lines. Importantly, induction of apoptosis following SREBP depletion was restricted to lipoprotein-deplete conditions. U87 glioblastoma cells were highly susceptible to silencing of either SREBP isoform, and apoptosis induced by SREBP1 depletion in these cells was rescued by antioxidants or by restoring the levels of mono-unsaturated fatty acids. Moreover, silencing of SREBP1 induced ER-stress in U87 cells in lipoprotein-deplete conditions and prevented tumor growth in a xenograft model. Conclusions Taken together, these results demonstrate that regulation of lipid composition by SREBP is essential to maintain the balance between protein and lipid biosynthesis downstream of Akt and to prevent resultant ER-stress and cell death. Regulation of lipid metabolism by the Akt/mTORC1 signaling axis is required for the growth and survival of cancer cells.
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Affiliation(s)
- Beatrice Griffiths
- Gene Expression Analysis Laboratory, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London, WC2A 3LY, UK
| | - Caroline A Lewis
- Gene Expression Analysis Laboratory, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London, WC2A 3LY, UK.,Present address: Koch Institute for Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA
| | - Karim Bensaad
- CRUK Growth Factor Group, The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Headington, Oxford, OX3 9DS, UK
| | - Susana Ros
- Gene Expression Analysis Laboratory, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London, WC2A 3LY, UK
| | - Qifeng Zhang
- The Babraham Institute, Babraham Research Campus, Cambridge, CB22 3AT, UK
| | - Emma C Ferber
- Gene Expression Analysis Laboratory, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London, WC2A 3LY, UK
| | - Sofia Konisti
- Gene Expression Analysis Laboratory, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London, WC2A 3LY, UK.,Present address: Kennedy Institute of Rheumatology, Imperial College, 65 Aspenlea Road, London, Hammersmith, W6 8LH, UK
| | - Barrie Peck
- Gene Expression Analysis Laboratory, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London, WC2A 3LY, UK
| | - Heike Miess
- Gene Expression Analysis Laboratory, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London, WC2A 3LY, UK
| | - Philip East
- Bioinformatics and Biostatistics Service, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London, WC2A 3LY, UK
| | - Michael Wakelam
- The Babraham Institute, Babraham Research Campus, Cambridge, CB22 3AT, UK
| | - Adrian L Harris
- CRUK Growth Factor Group, The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Headington, Oxford, OX3 9DS, UK
| | - Almut Schulze
- Gene Expression Analysis Laboratory, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London, WC2A 3LY, UK
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35
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Cline A, Gao N, Flanagan-Steet H, Sharma V, Rosa S, Sonon R, Azadi P, Sadler KC, Freeze HH, Lehrman MA, Steet R. A zebrafish model of PMM2-CDG reveals altered neurogenesis and a substrate-accumulation mechanism for N-linked glycosylation deficiency. Mol Biol Cell 2012; 23:4175-87. [PMID: 22956764 PMCID: PMC3484097 DOI: 10.1091/mbc.e12-05-0411] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
PMM2-CDG patients have phosphomannomutase (Pmm2) deficiency, with developmental and N-linked glycosylation defects attributed to depletion of mannose-1-phosphate and downstream lipid-linked oligosaccharides (LLOs). This, the first PMM2-CDG zebrafish model, shows, unexpectedly, that accumulation of the Pmm2 substrate mannose-6-phosphate explains LLO deficiency. Congenital disorder of glycosylation (PMM2-CDG) results from mutations in pmm2, which encodes the phosphomannomutase (Pmm) that converts mannose-6-phosphate (M6P) to mannose-1-phosphate (M1P). Patients have wide-spectrum clinical abnormalities associated with impaired protein N-glycosylation. Although it has been widely proposed that Pmm2 deficiency depletes M1P, a precursor of GDP-mannose, and consequently suppresses lipid-linked oligosaccharide (LLO) levels needed for N-glycosylation, these deficiencies have not been demonstrated in patients or any animal model. Here we report a morpholino-based PMM2-CDG model in zebrafish. Morphant embryos had developmental abnormalities consistent with PMM2-CDG patients, including craniofacial defects and impaired motility associated with altered motor neurogenesis within the spinal cord. Significantly, global N-linked glycosylation and LLO levels were reduced in pmm2 morphants. Although M1P and GDP-mannose were below reliable detection/quantification limits, Pmm2 depletion unexpectedly caused accumulation of M6P, shown earlier to promote LLO cleavage in vitro. In pmm2 morphants, the free glycan by-products of LLO cleavage increased nearly twofold. Suppression of the M6P-synthesizing enzyme mannose phosphate isomerase within the pmm2 background normalized M6P levels and certain aspects of the craniofacial phenotype and abrogated pmm2-dependent LLO cleavage. In summary, we report the first zebrafish model of PMM2-CDG and uncover novel cellular insights not possible with other systems, including an M6P accumulation mechanism for underglycosylation.
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Affiliation(s)
- Abigail Cline
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
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36
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Landau G, Ran A, Bercovich Z, Feldmesser E, Horn-Saban S, Korkotian E, Jacob-Hirsh J, Rechavi G, Ron D, Kahana C. Expression profiling and biochemical analysis suggest stress response as a potential mechanism inhibiting proliferation of polyamine-depleted cells. J Biol Chem 2012; 287:35825-37. [PMID: 22942278 DOI: 10.1074/jbc.m112.381335] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Polyamines are small organic polycations that are absolutely required for cell growth and proliferation; yet the basis for this requirement is mostly unknown. Here, we combined a genome-wide expression profiling with biochemical analysis to reveal the molecular basis for inhibited proliferation of polyamine-depleted cells. Transcriptional responses accompanying growth arrest establishment in polyamine-depleted cells or growth resumption following polyamine replenishment were monitored and compared. Changes in the expression of genes related to various fundamental cellular processes were established. Analysis of mirror-symmetric expression patterns around the G(1)-arrest point identified a set of genes representing a stress-response signature. Indeed, complementary biochemical analysis demonstrated activation of the PKR-like endoplasmic reticulum kinase arm of the unfolded protein response and of the stress-induced p38 MAPK. These changes were accompanied by induction of key growth-inhibitory factors such as p21 and Gadd45a and reduced expression of various cyclins, most profoundly cyclin D1, setting the basis for the halted proliferation. However, although the induced stress response could arrest growth, polyamine depletion also inhibited proliferation of PKR-like endoplasmic reticulum kinase and p38α-deficient cells and of cells harboring a nonphosphorylatable mutant eIF2α (S51A), suggesting that additional yet unidentified mechanisms might inhibit proliferation of polyamine-depleted cells. Despite lengthy persistence of the stress and activation of apoptotic signaling, polyamine-depleted cells remained viable, apparently due to induced expression of protective genes and development of autophagy.
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Affiliation(s)
- Guy Landau
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
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37
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Fullwood MJ, Zhou W, Shenolikar S. Targeting Phosphorylation of Eukaryotic Initiation Factor-2α to Treat Human Disease. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2012; 106:75-106. [DOI: 10.1016/b978-0-12-396456-4.00005-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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38
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Carbon monoxide, a reaction product of heme oxygenase-1, suppresses the expression of C-reactive protein by endoplasmic reticulum stress through modulation of the unfolded protein response. Mol Immunol 2011; 48:1793-9. [DOI: 10.1016/j.molimm.2011.05.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Revised: 04/30/2011] [Accepted: 05/09/2011] [Indexed: 11/24/2022]
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Fribley AM, Cruz PG, Miller JR, Callaghan MU, Cai P, Narula N, Neubig RR, Showalter HD, Larsen SD, Kirchhoff PD, Larsen MJ, Burr DA, Schultz PJ, Jacobs RR, Tamayo-Castillo G, Ron D, Sherman DH, Kaufman RJ. Complementary cell-based high-throughput screens identify novel modulators of the unfolded protein response. ACTA ACUST UNITED AC 2011; 16:825-35. [PMID: 21844328 DOI: 10.1177/1087057111414893] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Despite advances toward understanding the prevention and treatment of many cancers, patients who suffer from oral squamous cell carcinoma (OSCC) confront a survival rate that has remained unimproved for more than 2 decades, indicating our ability to treat them pharmacologically has reached a plateau. In an ongoing effort to improve the clinical outlook for this disease, we previously reported that an essential component of the mechanism by which the proteasome inhibitor bortezomib (PS-341, Velcade) induced apoptosis in OSCC required the activation of a terminal unfolded protein response (UPR). Predicated on these studies, the authors hypothesized that high-throughput screening (HTS) of large diverse chemical libraries might identify more potent or selective small-molecule activators of the apoptotic arm of the UPR to control or kill OSCC. They have developed complementary cell-based assays using stably transfected CHO-K1 cell lines that individually assess the PERK/eIF2α/CHOP (apoptotic) or the IRE1/XBP1 (adaptive) UPR subpathways. An 66 K compound collection was screened at the University of Michigan Center for Chemical Genomics that included a unique library of prefractionated natural product extracts. The mycotoxin methoxycitrinin was isolated from a natural extract and found to selectively activate the CHOP-luciferase reporter at 80 µM. A series of citrinin derivatives was isolated from these extracts, including a unique congener that has not been previously described. In an effort to identify more potent compounds, the authors examined the ability of citrinin and the structurally related mycotoxins ochratoxin A and patulin to activate the UPR. Strikingly, it was found that patulin at 2.5 to 10 µM induced a terminal UPR in a panel of OSCC cells that was characterized by an increase in CHOP, GADD34, and ATF3 gene expression and XBP1 splicing. A luminescent caspase assay and the induction of several BH3-only genes indicated that patulin could induce apoptosis in OSCC cells. These data support the use of this complementary HTS strategy to identify novel modulators of UPR signaling and tumor cell death.
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Affiliation(s)
- Andrew M Fribley
- Carmen and Ann Adams Department of Pediatrics, Division of Hematology/Oncology, Wayne State University, 421 E. Canfield, Detroit, MI 48201, USA
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40
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Cinaroglu A, Gao C, Imrie D, Sadler KC. Activating transcription factor 6 plays protective and pathological roles in steatosis due to endoplasmic reticulum stress in zebrafish. Hepatology 2011; 54:495-508. [PMID: 21538441 PMCID: PMC3145024 DOI: 10.1002/hep.24396] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2011] [Accepted: 04/19/2011] [Indexed: 12/12/2022]
Abstract
UNLABELLED Many etiologies of fatty liver disease (FLD) are associated with the hyperactivation of one of the three pathways composing the unfolded protein response (UPR), which is a harbinger of endoplasmic reticulum (ER) stress. The UPR is mediated by pathways initiated by PRKR-like endoplasmic reticulum kinase, inositol-requiring 1A/X box binding protein 1, and activating transcription factor 6 (ATF6), and each of these pathways has been implicated to have a protective or pathological role in FLD. We used zebrafish with FLD and hepatic ER stress to explore the relationship between Atf6 and steatosis. A mutation of the foie gras (foigr) gene caused FLD and hepatic ER stress. The prolonged treatment of wild-type larvae with tunicamycin (TN), which caused chronic ER stress, phenocopied foigr. In contrast, acute exposure to a high dose of TN robustly activated the UPR but was less effective at inducing steatosis. The sterol regulatory element binding protein transcription factors were not required for steatosis in any of these models. Instead, depleting larvae of active Atf6 either through a membrane-bound transcription factor peptidase site 1 mutation or an atf6 morpholino injection protected them against steatosis caused by chronic ER stress, but exacerbated steatosis caused by acute TN treatment. CONCLUSION ER stress causes FLD. A loss of Atf6 prevents steatosis caused by chronic ER stress but can also potentiate steatosis caused by acute ER stress. This demonstrates that Atf6 can play both protective and pathological roles in FLD.
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Affiliation(s)
- Ayca Cinaroglu
- Department of Medicine/Division of Liver Diseases and Department of Developmental and Regenerative Biology, Gustave L. Levy Place Box 1020 New York, NY 10029
| | - Chuan Gao
- Department of Medicine/Division of Liver Diseases and Department of Developmental and Regenerative Biology, Gustave L. Levy Place Box 1020 New York, NY 10029
| | - Dru Imrie
- Department of Medicine/Division of Liver Diseases and Department of Developmental and Regenerative Biology, Gustave L. Levy Place Box 1020 New York, NY 10029
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Chen J, Li Q, Zhang Y, Yang P, Zong Y, Qu S, Liu Z. Oleic acid decreases the expression of a cholesterol transport-related protein (NPC1L1) by the induction of endoplasmic reticulum stress in CaCo-2 cells. J Physiol Biochem 2011; 67:153-63. [PMID: 21181463 DOI: 10.1007/s13105-010-0058-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Accepted: 10/13/2010] [Indexed: 01/07/2023]
Abstract
The reported data indicate that oleic acid (OA) decreases cholesterol absorption. To explore the underlying mechanisms, the effects of OA on the expression of cholesterol transport-related proteins (NPC1L1, ABCG5/8, ACAT2, MTP) and the unfolded protein response (UPR) pathway were studied in CaCo-2 enterocytes by incubating CaCo-2 cells with taurocholate micelles or taurocholate micelles containing different concentrations of OA (0.25-1.0 mM). We show that OA effectively induces XBP1 mRNA splicing, a key component of the UPR signaling, and the expression of BiP and mature ATF6 proteins in a concentration-dependent manner, leading to the induction of endoplasmic reticulum (ER) stress and activation of the UPR. Interestingly, OA decreases NPC1L1 expression in a dose-dependent manner while it has no effects on ABCG5 and MTP mRNA level or SREBP-2, ABCG8, and ACAT2 protein level. In CaCo-2 cells treated with 1.0 mM OA, both the NPC1L1 mRNA level and the NPC1L1 protein expression in brush-border membrane fractions were decreased by 39% and 37%, respectively (P < 0.01). A dose of 1 mM dithiothreitol (DTT), a positive control for ER stress induction, also decreases NPC1L1 mRNA and protein expression by 27% and 23%, respectively (P < 0.05). Furthermore, 4-phenyl-butyric acid, an UPR inhibitor, blocks OA- and DTT-induced reduction on NPC1L1 mRNA and protein levels. The results suggest that OA down-regulates NPC1L1 mRNA and protein expression via the induction of the UPR, which may play an important role in reducing intestinal cholesterol absorption.
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Affiliation(s)
- Jiangyuan Chen
- Department of Biochemistry and Molecular Biology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
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Blais JD, Chin KT, Zito E, Zhang Y, Heldman N, Harding HP, Fass D, Thorpe C, Ron D. A small molecule inhibitor of endoplasmic reticulum oxidation 1 (ERO1) with selectively reversible thiol reactivity. J Biol Chem 2010; 285:20993-1003. [PMID: 20442408 PMCID: PMC2898301 DOI: 10.1074/jbc.m110.126599] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Revised: 04/28/2010] [Indexed: 01/29/2023] Open
Abstract
Endoplasmic reticulum oxidation 1 (ERO1) is a conserved eukaryotic flavin adenine nucleotide-containing enzyme that promotes disulfide bond formation by accepting electrons from reduced protein disulfide isomerase (PDI) and passing them on to molecular oxygen. Although disulfide bond formation is an essential process, recent experiments suggest a surprisingly broad tolerance to genetic manipulations that attenuate the rate of disulfide bond formation and that a hyperoxidizing ER may place stressed cells at a disadvantage. In this study, we report on the development of a high throughput in vitro assay for mammalian ERO1alpha activity and its application to identify small molecule inhibitors. The inhibitor EN460 (IC(50), 1.9 mum) interacts selectively with the reduced, active form of ERO1alpha and prevents its reoxidation. Despite rapid and promiscuous reactivity with thiolates, EN460 exhibits selectivity for ERO1. This selectivity is explained by the rapid reversibility of the reaction of EN460 with unstructured thiols, in contrast to the formation of a stable bond with ERO1alpha followed by displacement of bound flavin adenine dinucleotide from the active site of the enzyme. Modest concentrations of EN460 and a functionally related inhibitor, QM295, promote signaling in the unfolded protein response and precondition cells against severe ER stress. Together, these observations point to the feasibility of targeting the enzymatic activity of ERO1alpha with small molecule inhibitors.
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Affiliation(s)
- Jaime D. Blais
- From the Kimmel Center for Biology and Medicine of the Skirball Institute and the Departments of Cell Biology and Medicine, New York University School of Medicine, New York, New York 10016
| | - King-Tung Chin
- From the Kimmel Center for Biology and Medicine of the Skirball Institute and the Departments of Cell Biology and Medicine, New York University School of Medicine, New York, New York 10016
| | - Ester Zito
- From the Kimmel Center for Biology and Medicine of the Skirball Institute and the Departments of Cell Biology and Medicine, New York University School of Medicine, New York, New York 10016
| | - Yuhong Zhang
- From the Kimmel Center for Biology and Medicine of the Skirball Institute and the Departments of Cell Biology and Medicine, New York University School of Medicine, New York, New York 10016
| | - Nimrod Heldman
- the Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel, and
| | - Heather P. Harding
- From the Kimmel Center for Biology and Medicine of the Skirball Institute and the Departments of Cell Biology and Medicine, New York University School of Medicine, New York, New York 10016
- the Institute of Metabolic Science, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
| | - Deborah Fass
- the Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel, and
| | - Colin Thorpe
- the Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716
| | - David Ron
- From the Kimmel Center for Biology and Medicine of the Skirball Institute and the Departments of Cell Biology and Medicine, New York University School of Medicine, New York, New York 10016
- the Institute of Metabolic Science, University of Cambridge, Cambridge CB2 0QQ, United Kingdom
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Osborne TF, Espenshade PJ. Evolutionary conservation and adaptation in the mechanism that regulates SREBP action: what a long, strange tRIP it's been. Genes Dev 2009; 23:2578-91. [PMID: 19933148 DOI: 10.1101/gad.1854309] [Citation(s) in RCA: 197] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Sterol regulatory element-binding proteins (SREBPs) are a subfamily of basic helix-loop-helix leucine zipper (bHLH-LZ) transcription factors that are conserved from fungi to humans and are defined by two key features: a signature tyrosine residue in the DNA-binding domain, and a membrane-tethering domain that is a target for regulated proteolysis. Recent studies including genome-wide and model organism approaches indicate SREBPs coordinate cellular lipid metabolism with other cellular physiologic processes. These functions are broadly related as cellular adaptation to environmental changes ranging from nutrient fluctuations to toxin exposure. This review integrates classic features of the SREBP pathway with newer information regarding the regulation and sensing mechanisms that serve to assimilate different cellular physiologic processes for optimal function and growth.
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Affiliation(s)
- Timothy F Osborne
- Department of Molecular Biology and Biochemistry, University of California at Irvine, Irvine, California 92697, USA.
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Timosaponin AIII is preferentially cytotoxic to tumor cells through inhibition of mTOR and induction of ER stress. PLoS One 2009; 4:e7283. [PMID: 19789631 PMCID: PMC2747272 DOI: 10.1371/journal.pone.0007283] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2009] [Accepted: 09/10/2009] [Indexed: 12/31/2022] Open
Abstract
The aqueous extract of Anemarrhena asphodeloides (BN108) induces apoptosis in various cancer cell lines but is significantly less cytotoxic in non-transformed cells. Chemical fractionation of BN108 showed that its cytotoxicity is associated with timosaponins, steroidal saponins of coprostane type. Timosaponin BII (TBII) is a major saponin in BN108, but it shows little cytotoxicity. A much less abundant TAIII induces cell death in tumor cells but not in normal cells, reproducing the selectivity of the total extract BN108. Glycosidase treatment, by removing the extra sugar moiety in TBII, converts it to TAIII and confers cytotoxic activity. Analysis of the mechanisms of death induced by TAIII revealed activation of two distinct pro-apoptotic pathways: first, inhibition of mTORC1 manifested in much reduced phosphorylation of mTORC1 targets; second, induction of endoplasmic reticulum stress culminating in phosphorylation of eIF2α and activation of caspase 4. These pro-apoptotic pathways are activated by TAIII selectively in tumor cells but not in normal cells. Both pathways play a causative role in TAIII cytotoxicity, as restoration of either mTOR activity or relief of ER stress alone offer only partial protection from TAIII. Inhibition of mTORC1 and induction of ER stress apparently contribute to the induction of the previously reported autophagic response in TAIII-treated cells. TAIII induced autophagy plays a protective role in TAIII induced death signaling, and failure to mount autophagic response is associated with heightened sensitivity to TAIII induced apoptosis. The multiple death-promoting and apparently tumor-selective responses to TAIII, its ability to inhibit mTORC1, and the possibility of further enhancing its cytotoxicity by pharmacological inhibition of autophagy, make TAIII an attractive candidate for development as a cancer therapeutic agent.
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Størvold GL, Fleten KG, Olsen CG, Follestad T, Krokan HE, Schønberg SA. Docosahexaenoic Acid Activates Some SREBP-2 Targets Independent of Cholesterol and ER Stress in SW620 Colon Cancer Cells. Lipids 2009; 44:673-83. [DOI: 10.1007/s11745-009-3324-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2009] [Accepted: 06/15/2009] [Indexed: 11/28/2022]
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Besnard V, Wert SE, Stahlman MT, Postle AD, Xu Y, Ikegami M, Whitsett JA. Deletion of Scap in alveolar type II cells influences lung lipid homeostasis and identifies a compensatory role for pulmonary lipofibroblasts. J Biol Chem 2009; 284:4018-30. [PMID: 19074148 PMCID: PMC2635058 DOI: 10.1074/jbc.m805388200] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Revised: 11/21/2008] [Indexed: 12/22/2022] Open
Abstract
Pulmonary function after birth is dependent upon surfactant lipids that reduce surface tension in the alveoli. The sterol-responsive element-binding proteins (SREBPs) are transcription factors regulating expression of genes controlling lipid homeostasis in many tissues. To identify the role of SREBPs in the lung, we conditionally deleted the SREBP cleavage-activating protein gene, Scap, in respiratory epithelial cells (ScapDelta/Delta) in vivo. Prior to birth (E18.5), deletion of Scap decreased the expression of both SREBPs and a number of genes regulating fatty acid and cholesterol metabolism. Nevertheless, ScapDelta/Delta mice survived postnatally, surfactant and lung tissue lipids being substantially normalized in adult ScapDelta/Delta mice. Although phospholipid synthesis was decreased in type II cells from adult ScapDelta/Delta mice, lipid storage, synthesis, and transfer by lung lipofibroblasts were increased. mRNA microarray data indicated that SCAP influenced two major gene networks, one regulating lipid metabolism and the other stress-related responses. Deletion of the SCAP/SREBP pathway in respiratory epithelial cells altered lung lipid homeostasis and induced compensatory lipid accumulation and synthesis in lung lipofibroblasts.
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Affiliation(s)
- Valérie Besnard
- Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Department of Pediatrics, the University of Cincinnati College of Medicine, Cincinnati, Ohio 45229-3039, USA
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Kovacs WJ, Tape KN, Shackelford JE, Wikander TM, Richards MJ, Fliesler SJ, Krisans SK, Faust PL. Peroxisome deficiency causes a complex phenotype because of hepatic SREBP/Insig dysregulation associated with endoplasmic reticulum stress. J Biol Chem 2008; 284:7232-45. [PMID: 19110480 DOI: 10.1074/jbc.m809064200] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Regulation of hepatic cholesterol biosynthesis, lipogenesis, and insulin signaling intersect at the transcriptional level by control of SREBP and Insig genes. We previously demonstrated that peroxisome-deficient PEX2-/- mice activate SREBP-2 pathways but are unable to maintain normal cholesterol homeostasis. In this study, we demonstrate that oral bile acid treatment normalized hepatic and plasma cholesterol levels and hepatic cholesterol synthesis in early postnatal PEX2 mutants, but SREBP-2 and its target gene expressions remained increased. SREBP-2 pathway induction was also observed in neonatal and longer surviving PEX2 mutants, where hepatic cholesterol levels were normal. Abnormal expression patterns for SREBP-1c and Insig-2a, and novel regulation of Insig-2b, further demonstrate that peroxisome deficiency widely affects the regulation of related metabolic pathways. We have provided the first demonstration that peroxisome deficiency activates hepatic endoplasmic reticulum (ER) stress pathways, especially the integrated stress response mediated by PERK and ATF4 signaling. Our studies suggest a mechanism whereby ER stress leads to dysregulation of the endogenous sterol response mechanism and concordantly activates oxidative stress pathways. Several metabolic derangements in peroxisome-deficient PEX2-/- liver are likely to trigger ER stress, including perturbed flux of mevalonate metabolites, altered bile acid homeostasis, changes in fatty acid levels and composition, and oxidative stress.
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Affiliation(s)
- Werner J Kovacs
- Institute of Cell Biology, ETH Zürich, CH-8093 Zürich, Switzerland.
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PERK-dependent regulation of lipogenesis during mouse mammary gland development and adipocyte differentiation. Proc Natl Acad Sci U S A 2008; 105:16314-9. [PMID: 18852460 DOI: 10.1073/pnas.0808517105] [Citation(s) in RCA: 206] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The role of the endoplasmic reticulum stress-regulated kinase, PERK, in mammary gland function was assessed through generation of a targeted deletion in mammary epithelium. Characterization revealed that PERK is required for functional maturation of milk-secreting mammary epithelial cells. PERK-dependent signaling contributes to lipogenic differentiation in mammary epithelium, and perk deletion inhibits the sustained expression of lipogenic enzymes FAS, ACL, and SCD1. As a result, mammary tissue has reduced lipid content and the milk produced has altered lipid composition, resulting in attenuated pup growth. Consistent with PERK-dependent regulation of the lipogenic pathway, loss of PERK inhibits expression of FAS, ACL, and SCD1 in immortalized murine embryonic fibroblasts when cultured under conditions favoring adipocyte differentiation. These findings implicate PERK as a physiologically relevant regulator of the lipogenic pathway.
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Jakobsen CH, Størvold GL, Bremseth H, Follestad T, Sand K, Mack M, Olsen KS, Lundemo AG, Iversen JG, Krokan HE, Schønberg SA. DHA induces ER stress and growth arrest in human colon cancer cells: associations with cholesterol and calcium homeostasis. J Lipid Res 2008; 49:2089-100. [PMID: 18566476 PMCID: PMC2533412 DOI: 10.1194/jlr.m700389-jlr200] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Polyunsaturated fatty acids (PUFAs) are normal constituents of the diet, but have properties different from other fatty acids (e.g., through generation of signaling molecules). N-3 PUFAs reduce cancer cell growth, but no unified mechanism has been identified. We show that docosahexaenoic acid (DHA; 22:6 n-3) causes extensive changes in gene expression patterns at mRNA level in the colon cancer cell line SW620. Early changes include unfolded protein response (UPR) and increased levels of phosphorylated eIF2α as verified at protein level. The latter is considered a hallmark of endoplasmic reticulum (ER) stress and is abundantly present already after 3 h. It may coordinate many of the downstream changes observed, including signaling pathways for cell cycle arrest/apoptosis, calcium homeostasis, cholesterol metabolism, ubiquitination, and proteasomal degradation. Also, eicosapentaenoic acid (EPA), but not oleic acid (OA), induced key mediators of ER stress and UPR at protein level. Accumulation of esterified cholesterol was not compensated for by increased total levels of cholesterol, and mRNAs for cholesterol biosynthesis as well as de novo synthesis of cholesterol were reduced. These results suggest that cytotoxic effects of DHA are associated with signaling pathways involving lipid metabolism and ER stress.
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Affiliation(s)
- Caroline Hild Jakobsen
- Department of Laboratory Medicine, Children's and Women's Health, Norwegian University of Science and Technology (NTNU), Erling Skjalgssons gate 1, N-7006 Trondheim, Norway
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50
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Abstract
Cholesterol is an essential component of mammalian cell membranes and is required for proper membrane permeability, fluidity, organelle identity, and protein function. Cells maintain sterol homeostasis by multiple feedback controls that act through transcriptional and posttranscriptional mechanisms. The membrane-bound transcription factor sterol regulatory element binding protein (SREBP) is the principal regulator of both sterol synthesis and uptake. In mammalian cells, the ER membrane protein Insig has emerged as a key component of homeostatic regulation by controlling both the activity of SREBP and the sterol-dependent degradation of the biosynthetic enzyme HMG-CoA reductase. In this review, we focus on recent advances in our understanding of the molecular mechanisms of the regulation of sterol synthesis. A comparative analysis of SREBP and HMG-CoA reductase regulation in mammals, yeast, and flies points toward an equilibrium model for how lipid signals regulate the activity of sterol-sensing proteins and their downstream effectors.
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Affiliation(s)
- Peter J Espenshade
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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