1
|
Angeles-Floriano T, Sanjuan-Méndez A, Rivera-Torruco G, Parra-Ortega I, Lopez-Martinez B, Martinez-Castro J, Marin-Santiago S, Alcántara-Hernández C, Martínez-Martínez A, Márquez-González H, Klünder-Klünder M, Olivar-López V, Zaragoza-Ojeda M, Arenas-Huertero F, Torres-Aguilar H, Medina-Contreras O, Zlotnik A, Valle-Rios R. Leukocyte surface expression of the endoplasmic reticulum chaperone GRP78 is increased in severe COVID-19. J Leukoc Biol 2023; 113:1-10. [PMID: 36822163 DOI: 10.1093/jleuko/qiac017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Indexed: 01/12/2023] Open
Abstract
Hyperinflammation present in individuals with severe COVID-19 has been associated with an exacerbated cytokine production and hyperactivated immune cells. Endoplasmic reticulum stress leading to the unfolded protein response has been recently reported as an active player in inducing inflammatory responses. Once unfolded protein response is activated, GRP78, an endoplasmic reticulum-resident chaperone, is translocated to the cell surface (sGRP78), where it is considered a cell stress marker; however, its presence has not been evaluated in immune cells during disease. Here we assessed the presence of sGRP78 on different cell subsets in blood samples from severe or convalescent COVID-19 patients. The frequency of CD45+sGRP78+ cells was higher in patients with the disease compared to convalescent patients. The latter showed similar frequencies to healthy controls. In patients with COVID-19, the lymphoid compartment showed the highest presence of sGRP78+ cells versus the myeloid compartment. CCL2, TNF-α, C-reactive protein, and international normalized ratio measurements showed a positive correlation with the frequency of CD45+sGRP78+ cells. Finally, gene expression microarray data showed that activated T and B cells increased the expression of GRP78, and peripheral blood mononuclear cells from healthy donors acquired sGRP78 upon activation with ionomycin and PMA. Thus, our data highlight the association of sGRP78 on immune cells in patients with severe COVID-19.
Collapse
Affiliation(s)
- Tania Angeles-Floriano
- División de Investigación, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico.,Programa de Maestría y Doctorado en Ciencias Médicas Odontológicas y de la Salud, Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico.,Unidad de Investigación en Inmunología y Proteómica, Hospital Infantil de México Federico Gómez, Mexico City, Mexico
| | - Adriana Sanjuan-Méndez
- División de Investigación, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico.,Unidad de Investigación en Inmunología y Proteómica, Hospital Infantil de México Federico Gómez, Mexico City, Mexico.,Programa de Maestría en Biomedicina Experimental, Facultad de Medicina y Cirugía, Universidad Autónoma Benito Juárez de Oaxaca, Oaxaca City, Mexico
| | - Guadalupe Rivera-Torruco
- División de Investigación, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico.,Unidad de Investigación en Inmunología y Proteómica, Hospital Infantil de México Federico Gómez, Mexico City, Mexico.,Departamento de Fisiología y Neurociencias, Centro de Investigación y de Estudios Avanzados (CINVESTAV), Mexico City, Mexico
| | - Israel Parra-Ortega
- Departamento de Laboratorio Clínico, Hospital Infantil de México Federico Gómez, Mexico City, Mexico
| | - Briceida Lopez-Martinez
- Departamento de Laboratorio Clínico, Hospital Infantil de México Federico Gómez, Mexico City, Mexico
| | - Jesús Martinez-Castro
- Departamento de Medicina Interna, Centro Médico Lic, Adolfo López Mateos de Toluca, Toluca City, Mexico
| | - Sergio Marin-Santiago
- Departamento de Medicina Interna, Centro Médico Lic, Adolfo López Mateos de Toluca, Toluca City, Mexico
| | | | - Araceli Martínez-Martínez
- Departamento de Medicina Interna, Centro Médico Lic, Adolfo López Mateos de Toluca, Toluca City, Mexico
| | - Horacio Márquez-González
- Departamento de Investigación Clínica, Hospital Infantil de México Federico Gómez, Mexico City, Mexico
| | - Miguel Klünder-Klünder
- Subdirección de Investigación, Hospital Infantil de México Federico Gómez, Mexico City, Mexico
| | - Victor Olivar-López
- Departamento de Urgencias Pediátricas, Hospital Infantil de México Federico Gómez, Mexico City, Mexico
| | - Montserrat Zaragoza-Ojeda
- Laboratorio de Investigación en Patología Experimental, Hospital Infantil de México Federico Gómez, Mexico City, Mexico
| | - Francisco Arenas-Huertero
- Laboratorio de Investigación en Patología Experimental, Hospital Infantil de México Federico Gómez, Mexico City, Mexico
| | - Honorio Torres-Aguilar
- Facultad de Ciencias Químicas, Universidad Autónoma Benito Juárez de Oaxaca, Oaxaca City, Mexico
| | - Oscar Medina-Contreras
- Unidad de Investigación Epidemiológica en Endocrinología y Nutrición, Hospital Infantil de México Federico Gómez, Mexico City, Mexico
| | - Albert Zlotnik
- Department of Physiology and Biophysics, University of California, Irvine, CA, United States
| | - Ricardo Valle-Rios
- División de Investigación, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico.,Unidad de Investigación en Inmunología y Proteómica, Hospital Infantil de México Federico Gómez, Mexico City, Mexico
| |
Collapse
|
2
|
Varney MJ, Steyaert W, Coucke PJ, Delanghe JR, Uehling DE, Joseph B, Marcellus R, Al-Awar R, Benovic JL. G protein-coupled receptor kinase 6 (GRK6) regulates insulin processing and secretion via effects on proinsulin conversion to insulin. J Biol Chem 2022; 298:102421. [PMID: 36030052 PMCID: PMC9526158 DOI: 10.1016/j.jbc.2022.102421] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 08/16/2022] [Accepted: 08/18/2022] [Indexed: 11/07/2022] Open
Abstract
Recent studies identified a missense mutation in the gene coding for G protein–coupled receptor kinase 6 (GRK6) that segregates with type 2 diabetes (T2D). To better understand how GRK6 might be involved in T2D, we used pharmacological inhibition and genetic knockdown in the mouse β-cell line, MIN6, to determine whether GRK6 regulates insulin dynamics. We show inhibition of GRK5 and GRK6 increased insulin secretion but reduced insulin processing while GRK6 knockdown revealed these same processing defects with reduced levels of cellular insulin. GRK6 knockdown cells also had attenuated insulin secretion but enhanced proinsulin secretion consistent with decreased processing. In support of these findings, we demonstrate GRK6 rescue experiments in knockdown cells restored insulin secretion after glucose treatment. The altered insulin profile appears to be caused by changes in the proprotein convertases, the enzymes responsible for proinsulin to insulin conversion, as GRK6 knockdown resulted in significantly reduced convertase expression and activity. To identify how the GRK6-P384S mutation found in T2D patients might affect insulin processing, we performed biochemical and cell biological assays to study the properties of the mutant. We found that while GRK6-P384S was more active than WT GRK6, it displayed a cytosolic distribution in cells compared to the normal plasma membrane localization of GRK6. Additionally, GRK6 overexpression in MIN6 cells enhanced proinsulin processing, while GRK6-P384S expression had little effect. Taken together, our data show that GRK6 regulates insulin processing and secretion in a glucose-dependent manner and provide a foundation for understanding the contribution of GRK6 to T2D.
Collapse
Affiliation(s)
- Matthew J Varney
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Wouter Steyaert
- Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands; Center for Medical Genetics, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Paul J Coucke
- Center for Medical Genetics, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Joris R Delanghe
- Department of Diagnostic Sciences, Ghent University, Ghent, Belgium
| | - David E Uehling
- Drug Discovery Program, Ontario Institute for Cancer Research, Toronto, Ontario M5G 0A3, Canada
| | - Babu Joseph
- Drug Discovery Program, Ontario Institute for Cancer Research, Toronto, Ontario M5G 0A3, Canada
| | - Richard Marcellus
- Drug Discovery Program, Ontario Institute for Cancer Research, Toronto, Ontario M5G 0A3, Canada
| | - Rima Al-Awar
- Drug Discovery Program, Ontario Institute for Cancer Research, Toronto, Ontario M5G 0A3, Canada; Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Jeffrey L Benovic
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA.
| |
Collapse
|
3
|
Li J, Inoue R, Togashi Y, Okuyama T, Satoh A, Kyohara M, Nishiyama K, Tsuno T, Miyashita D, Kin T, Shapiro AMJ, Chew RSE, Teo AKK, Oyadomari S, Terauchi Y, Shirakawa J. Imeglimin Ameliorates β-Cell Apoptosis by Modulating the Endoplasmic Reticulum Homeostasis Pathway. Diabetes 2022; 71:424-439. [PMID: 34588186 DOI: 10.2337/db21-0123] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 09/20/2021] [Indexed: 02/05/2023]
Abstract
The effects of imeglimin, a novel antidiabetes agent, on β-cell function remain unclear. Here, we unveiled the impact of imeglimin on β-cell survival. Treatment with imeglimin augmented mitochondrial function, enhanced insulin secretion, promoted β-cell proliferation, and improved β-cell survival in mouse islets. Imeglimin upregulated the expression of endoplasmic reticulum (ER)-related molecules, including Chop (Ddit3), Gadd34 (Ppp1r15a), Atf3, and Sdf2l1, and decreased eIF2α phosphorylation after treatment with thapsigargin and restored global protein synthesis in β-cells under ER stress. Imeglimin failed to protect against ER stress-induced β-cell apoptosis in CHOP-deficient islets or in the presence of GADD34 inhibitor. Treatment with imeglimin showed a significant decrease in the number of apoptotic β-cells and increased β-cell mass in Akita mice. Imeglimin also protected against β-cell apoptosis in both human islets and human pluripotent stem cell-derived β-like cells. Taken together, imeglimin modulates the ER homeostasis pathway, which results in the prevention of β-cell apoptosis both in vitro and in vivo.
Collapse
Affiliation(s)
- Jinghe Li
- Laboratory of Diabetes and Metabolic Disorders, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
| | - Ryota Inoue
- Laboratory of Diabetes and Metabolic Disorders, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
| | - Yu Togashi
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
| | - Tomoko Okuyama
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
| | - Aoi Satoh
- Laboratory of Diabetes and Metabolic Disorders, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
| | - Mayu Kyohara
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
| | - Kuniyuki Nishiyama
- Laboratory of Diabetes and Metabolic Disorders, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
| | - Takahiro Tsuno
- Laboratory of Diabetes and Metabolic Disorders, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
| | - Daisuke Miyashita
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
| | - Tatsuya Kin
- Clinical Islet Laboratory and Clinical Islet Transplant Program, University of Alberta, Edmonton, Alberta, Canada
| | - A M James Shapiro
- Clinical Islet Laboratory and Clinical Islet Transplant Program, University of Alberta, Edmonton, Alberta, Canada
| | - Resilind Su Ern Chew
- Stem Cells and Diabetes Laboratory, Institute of Molecular and Cell Biology, A*STAR, Proteos, Singapore
| | - Adrian Kee Keong Teo
- Stem Cells and Diabetes Laboratory, Institute of Molecular and Cell Biology, A*STAR, Proteos, Singapore
- Departments of Biochemistry and Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Seiichi Oyadomari
- Division of Molecular Biology, Institute of Advanced Medical Sciences, Tokushima University, Kuramoto, Tokushima, Japan
| | - Yasuo Terauchi
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
| | - Jun Shirakawa
- Laboratory of Diabetes and Metabolic Disorders, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
| |
Collapse
|
4
|
Anderson-Baucum E, Piñeros AR, Kulkarni A, Webb-Robertson BJ, Maier B, Anderson RM, Wu W, Tersey SA, Mastracci TL, Casimiro I, Scheuner D, Metz TO, Nakayasu ES, Evans-Molina C, Mirmira RG. Deoxyhypusine synthase promotes a pro-inflammatory macrophage phenotype. Cell Metab 2021; 33:1883-1893.e7. [PMID: 34496231 PMCID: PMC8432737 DOI: 10.1016/j.cmet.2021.08.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 06/01/2021] [Accepted: 08/05/2021] [Indexed: 12/24/2022]
Abstract
The metabolic inflammation (meta-inflammation) of obesity is characterized by proinflammatory macrophage infiltration into adipose tissue. Catalysis by deoxyhypusine synthase (DHPS) modifies the translation factor eIF5A to generate a hypusine (Hyp) residue. Hypusinated eIF5A (eIF5AHyp) controls the translation of mRNAs involved in inflammation, but its role in meta-inflammation has not been elucidated. Levels of eIF5AHyp were found to be increased in adipose tissue macrophages from obese mice and in murine macrophages activated to a proinflammatory M1-like state. Global proteomics and transcriptomics revealed that DHPS deficiency in macrophages altered the abundance of proteins involved in NF-κB signaling, likely through translational control of their respective mRNAs. DHPS deficiency in myeloid cells of obese mice suppressed M1 macrophage accumulation in adipose tissue and improved glucose tolerance. These findings indicate that DHPS promotes the post-transcriptional regulation of a subset of mRNAs governing inflammation and chemotaxis in macrophages and contributes to a proinflammatory M1-like phenotype.
Collapse
Affiliation(s)
- Emily Anderson-Baucum
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Annie R Piñeros
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Abhishek Kulkarni
- Department of Medicine, The University of Chicago, Chicago, IL 60637, USA
| | | | - Bernhard Maier
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Ryan M Anderson
- Department of Medicine, The University of Chicago, Chicago, IL 60637, USA
| | - Wenting Wu
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Sarah A Tersey
- Department of Medicine, The University of Chicago, Chicago, IL 60637, USA
| | - Teresa L Mastracci
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA
| | - Isabel Casimiro
- Department of Medicine, The University of Chicago, Chicago, IL 60637, USA
| | - Donalyn Scheuner
- Indiana Biosciences Research Institute, Indianapolis, IN 46202, USA
| | - Thomas O Metz
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Ernesto S Nakayasu
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Carmella Evans-Molina
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Roudebush VA Medical Center, Indianapolis, IN 46202, USA.
| | | |
Collapse
|
5
|
van den Akker GGH, Zacchini F, Housmans BAC, van der Vloet L, Caron MMJ, Montanaro L, Welting TJM. Current Practice in Bicistronic IRES Reporter Use: A Systematic Review. Int J Mol Sci 2021; 22:5193. [PMID: 34068921 PMCID: PMC8156625 DOI: 10.3390/ijms22105193] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 05/05/2021] [Accepted: 05/12/2021] [Indexed: 12/26/2022] Open
Abstract
Bicistronic reporter assays have been instrumental for transgene expression, understanding of internal ribosomal entry site (IRES) translation, and identification of novel cap-independent translational elements (CITE). We observed a large methodological variability in the use of bicistronic reporter assays and data presentation or normalization procedures. Therefore, we systematically searched the literature for bicistronic IRES reporter studies and analyzed methodological details, data visualization, and normalization procedures. Two hundred fifty-seven publications were identified using our search strategy (published 1994-2020). Experimental studies on eukaryotic adherent cell systems and the cell-free translation assay were included for further analysis. We evaluated the following methodological details for 176 full text articles: the bicistronic reporter design, the cell line or type, transfection methods, and time point of analyses post-transfection. For the cell-free translation assay, we focused on methods of in vitro transcription, type of translation lysate, and incubation times and assay temperature. Data can be presented in multiple ways: raw data from individual cistrons, a ratio of the two, or fold changes thereof. In addition, many different control experiments have been suggested when studying IRES-mediated translation. In addition, many different normalization and control experiments have been suggested when studying IRES-mediated translation. Therefore, we also categorized and summarized their use. Our unbiased analyses provide a representative overview of bicistronic IRES reporter use. We identified parameters that were reported inconsistently or incompletely, which could hamper data reproduction and interpretation. On the basis of our analyses, we encourage adhering to a number of practices that should improve transparency of bicistronic reporter data presentation and improve methodological descriptions to facilitate data replication.
Collapse
Affiliation(s)
- Guus Gijsbertus Hubert van den Akker
- Department of Orthopedic Surgery, Maastricht University, Medical Center+, 6229 ER Maastricht, The Netherlands; (G.G.H.v.d.A.); (B.A.C.H.); (L.v.d.V.); (M.M.J.C.)
| | - Federico Zacchini
- Department of Experimental, Diagnostic and Specialty Medicine, Bologna University, I-40138 Bologna, Italy; (F.Z.); (L.M.)
- Centro di Ricerca Biomedica Applicata—CRBA, Bologna University, Policlinico di Sant’Orsola, I-40138 Bologna, Italy
| | - Bas Adrianus Catharina Housmans
- Department of Orthopedic Surgery, Maastricht University, Medical Center+, 6229 ER Maastricht, The Netherlands; (G.G.H.v.d.A.); (B.A.C.H.); (L.v.d.V.); (M.M.J.C.)
| | - Laura van der Vloet
- Department of Orthopedic Surgery, Maastricht University, Medical Center+, 6229 ER Maastricht, The Netherlands; (G.G.H.v.d.A.); (B.A.C.H.); (L.v.d.V.); (M.M.J.C.)
| | - Marjolein Maria Johanna Caron
- Department of Orthopedic Surgery, Maastricht University, Medical Center+, 6229 ER Maastricht, The Netherlands; (G.G.H.v.d.A.); (B.A.C.H.); (L.v.d.V.); (M.M.J.C.)
| | - Lorenzo Montanaro
- Department of Experimental, Diagnostic and Specialty Medicine, Bologna University, I-40138 Bologna, Italy; (F.Z.); (L.M.)
- Centro di Ricerca Biomedica Applicata—CRBA, Bologna University, Policlinico di Sant’Orsola, I-40138 Bologna, Italy
- Programma Dipartimentale in Medicina di Laboratorio, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Via Albertoni 15, I-40138 Bologna, Italy
| | - Tim Johannes Maria Welting
- Department of Orthopedic Surgery, Maastricht University, Medical Center+, 6229 ER Maastricht, The Netherlands; (G.G.H.v.d.A.); (B.A.C.H.); (L.v.d.V.); (M.M.J.C.)
| |
Collapse
|
6
|
Templin AT, Mellati M, Meier DT, Esser N, Hogan MF, Castillo JJ, Akter R, Raleigh DP, Zraika S, Hull RL, Kahn SE. Low concentration IL-1β promotes islet amyloid formation by increasing hIAPP release from humanised mouse islets in vitro. Diabetologia 2020; 63:2385-2395. [PMID: 32728889 PMCID: PMC7529980 DOI: 10.1007/s00125-020-05232-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 06/05/2020] [Indexed: 01/09/2023]
Abstract
AIMS/HYPOTHESIS Aggregation of the beta cell secretory product human islet amyloid polypeptide (hIAPP) results in islet amyloid deposition, a pathological feature of type 2 diabetes. Amyloid formation is associated with increased levels of islet IL-1β as well as beta cell dysfunction and death, but the mechanisms that promote amyloid deposition in situ remain unclear. We hypothesised that physiologically relevant concentrations of IL-1β stimulate beta cell islet amyloid polypeptide (IAPP) release and promote amyloid formation. METHODS We used a humanised mouse model of endogenous beta cell hIAPP expression to examine whether low (pg/ml) concentrations of IL-1β promote islet amyloid formation in vitro. Amyloid-forming islets were cultured for 48 h in the presence or absence of IL-1β with or without an IL-1β neutralising antibody. Islet morphology was assessed by immunohistochemistry and islet mRNA expression, hormone content and release were also quantified. Cell-free thioflavin T assays were used to monitor hIAPP aggregation kinetics in the presence and absence of IL-1β. RESULTS Treatment with a low concentration of IL-1β (4 pg/ml) for 48 h increased islet amyloid prevalence (93.52 ± 3.89% vs 43.83 ± 9.67% amyloid-containing islets) and amyloid severity (4.45 ± 0.82% vs 2.16 ± 0.50% amyloid area/islet area) in hIAPP-expressing mouse islets in vitro. This effect of IL-1β was reduced when hIAPP-expressing islets were co-treated with an IL-1β neutralising antibody. Cell-free hIAPP aggregation assays showed no effect of IL-1β on hIAPP aggregation in vitro. Low concentration IL-1β did not increase markers of the unfolded protein response (Atf4, Ddit3) or alter proIAPP processing enzyme gene expression (Pcsk1, Pcsk2, Cpe) in hIAPP-expressing islets. However, release of IAPP and insulin were increased over 48 h in IL-1β-treated vs control islets (IAPP 0.409 ± 0.082 vs 0.165 ± 0.051 pmol/5 islets; insulin 87.5 ± 8.81 vs 48.3 ± 17.3 pmol/5 islets), and this effect was blocked by co-treatment with IL-1β neutralising antibody. CONCLUSIONS/INTERPRETATION Under amyloidogenic conditions, physiologically relevant levels of IL-1β promote islet amyloid formation by increasing beta cell release of IAPP. Neutralisation of this effect of IL-1β may decrease the deleterious effects of islet amyloid formation on beta cell function and survival.
Collapse
Affiliation(s)
- Andrew T Templin
- Division of Metabolism, Endocrinology and Nutrition, Veteran Affairs Puget Sound Health Care System (151) and University of Washington, 1660 S. Columbian Way, Seattle, WA, 98108, USA
| | - Mahnaz Mellati
- Division of Metabolism, Endocrinology and Nutrition, Veteran Affairs Puget Sound Health Care System (151) and University of Washington, 1660 S. Columbian Way, Seattle, WA, 98108, USA
| | - Daniel T Meier
- Division of Metabolism, Endocrinology and Nutrition, Veteran Affairs Puget Sound Health Care System (151) and University of Washington, 1660 S. Columbian Way, Seattle, WA, 98108, USA
| | - Nathalie Esser
- Division of Metabolism, Endocrinology and Nutrition, Veteran Affairs Puget Sound Health Care System (151) and University of Washington, 1660 S. Columbian Way, Seattle, WA, 98108, USA
| | - Meghan F Hogan
- Division of Metabolism, Endocrinology and Nutrition, Veteran Affairs Puget Sound Health Care System (151) and University of Washington, 1660 S. Columbian Way, Seattle, WA, 98108, USA
| | - Joseph J Castillo
- Division of Metabolism, Endocrinology and Nutrition, Veteran Affairs Puget Sound Health Care System (151) and University of Washington, 1660 S. Columbian Way, Seattle, WA, 98108, USA
| | - Rehana Akter
- Department of Chemistry, Stony Brook University, Stony Brook, NY, USA
| | - Daniel P Raleigh
- Department of Chemistry, Stony Brook University, Stony Brook, NY, USA
| | - Sakeneh Zraika
- Division of Metabolism, Endocrinology and Nutrition, Veteran Affairs Puget Sound Health Care System (151) and University of Washington, 1660 S. Columbian Way, Seattle, WA, 98108, USA
| | - Rebecca L Hull
- Division of Metabolism, Endocrinology and Nutrition, Veteran Affairs Puget Sound Health Care System (151) and University of Washington, 1660 S. Columbian Way, Seattle, WA, 98108, USA
| | - Steven E Kahn
- Division of Metabolism, Endocrinology and Nutrition, Veteran Affairs Puget Sound Health Care System (151) and University of Washington, 1660 S. Columbian Way, Seattle, WA, 98108, USA.
| |
Collapse
|
7
|
Johar D, Ahmed SM, El Hayek S, Al-Dewik N, Bahbah EI, Omar NH, Mustafa M, Salman DO, Fahmey A, Mottawea M, Azouz RAM, Bernstein L. Diabetes-induced Proteome Changes Throughout Development. Endocr Metab Immune Disord Drug Targets 2020; 19:732-743. [PMID: 31038056 DOI: 10.2174/1871530319666190305153810] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 10/31/2018] [Accepted: 11/25/2018] [Indexed: 12/31/2022]
Abstract
BACKGROUND Diabetes Mellitus (DM) is a multisystemic disease involving the homeostasis of insulin secretion by the pancreatic islet beta cells (β-cells). It is associated with hypertension, renal disease, and arterial and arteriolar vascular diseases. DISCUSSION The classification of diabetes is identified as type 1 (gene linked β-cell destruction in childhood) and type 2 (late onset associated with β-cell overload and insulin resistance in peripheral tissues. Type 1 diabetes is characterized by insulin deficiency, type 2 diabetes by both insulin deficiency and insulin resistance. The former is a genetically programmed loss of insulin secretion whereas the latter constitutes a disruption of the homeostatic relationship between the opposing activity of β- cell insulin and alpha cell (α-cell) glucagon of the Islets of Langerhans. The condition could also occur in pregnancy, as a prenatal occurring event, possibly triggered by the hormonal changes of pregnancy combined with β-cell overload. This review discusses the molecular basis of the biomolecular changes that occur with respect to glucose homeostasis and related diseases in DM. The underlying link between pancreatic, renal, and microvascular diseases in DM is based on oxidative stress and the Unfolded Protein Response (UPR). CONCLUSION Studying proteome changes in diabetes can deepen our understanding of the biomolecular basis of disease and help us acquire more efficient therapies.
Collapse
Affiliation(s)
- Dina Johar
- Biomedical Science Program, University of Science and Technology, Zewail City of Science and Technology, Giza, Egypt and Biochemistry and Nutrition Department, Ain Shams University Faculty of Women for Arts, Sciences and Education, Heliopolis, Cairo, Egypt
| | - Sara M Ahmed
- Clinical Pathology Department, Faculty of Medicine (Girls), Al-Azhar University, Nasr City, Cairo, Egypt
| | - Samer El Hayek
- Department of Anatomy, Cell Biology, and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Nader Al-Dewik
- Qatar Medical Genetic Center, Pediatrics Department, Hamad General Hospital (HGH), Hamad Medical Corporation (HMC), Doha, Qatar
| | - Eshak I Bahbah
- Faculty of Medicine, Al-Azhar University, Damietta, P.C. 34511, Egypt
| | - Nabil H Omar
- Pharmacy Department, National Center for Cancer Care and Research, Hamad Medical Corporation, Doha, Qatar
| | | | - Doaa O Salman
- Genetics Unit, Histology and Cell biology department, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | - Asmaa Fahmey
- Faculty of Pharmacy, Al-Mansoura University, Al-Mansoura, Egypt
| | - Mohamed Mottawea
- Faculty of Pharmacy, Modern University for Technology and Information, Cairo, Egypt
| | - Rasha A M Azouz
- Molecular Biology Department, Genetic Engineering and Biotechnology Research Division, National Research Centre, Dokki, 12622 Giza, Egypt
| | - Larry Bernstein
- Triplex Consulting, 54 Firethorn Lane, Northampton, MA 01060, United States
| |
Collapse
|
8
|
Nakayasu ES, Syed F, Tersey SA, Gritsenko MA, Mitchell HD, Chan CY, Dirice E, Turatsinze JV, Cui Y, Kulkarni RN, Eizirik DL, Qian WJ, Webb-Robertson BJM, Evans-Molina C, Mirmira RG, Metz TO. Comprehensive Proteomics Analysis of Stressed Human Islets Identifies GDF15 as a Target for Type 1 Diabetes Intervention. Cell Metab 2020; 31:363-374.e6. [PMID: 31928885 PMCID: PMC7319177 DOI: 10.1016/j.cmet.2019.12.005] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 09/03/2019] [Accepted: 12/12/2019] [Indexed: 01/03/2023]
Abstract
Type 1 diabetes (T1D) results from the progressive loss of β cells, a process propagated by pro-inflammatory cytokine signaling that disrupts the balance between pro- and anti-apoptotic proteins. To identify proteins involved in this process, we performed comprehensive proteomics of human pancreatic islets treated with interleukin-1β and interferon-γ, leading to the identification of 11,324 proteins, of which 387 were significantly regulated by treatment. We then tested the function of growth/differentiation factor 15 (GDF15), which was repressed by the treatment. We found that GDF15 translation was blocked during inflammation, and it was depleted in islets from individuals with T1D. The addition of exogenous GDF15 inhibited interleukin-1β+interferon-γ-induced apoptosis of human islets. Administration of GDF15 reduced by 53% the incidence of diabetes in NOD mice. Our approach provides a unique resource for the identification of the human islet proteins regulated by cytokines and was effective in discovering a potential target for T1D therapy.
Collapse
Affiliation(s)
- Ernesto S Nakayasu
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Farooq Syed
- Center for Diabetes and Metabolic Diseases and the Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Sarah A Tersey
- Center for Diabetes and Metabolic Diseases and the Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Marina A Gritsenko
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Hugh D Mitchell
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Chi Yuet Chan
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Ercument Dirice
- Department of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital, and Harvard Stem Cell Institute, Boston, MA, USA
| | - Jean-Valery Turatsinze
- ULB Center for Diabetes Research, Medical Faculty, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Yi Cui
- Environmental and Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Rohit N Kulkarni
- Department of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital, and Harvard Stem Cell Institute, Boston, MA, USA
| | - Decio L Eizirik
- ULB Center for Diabetes Research, Medical Faculty, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Wei-Jun Qian
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Bobbie-Jo M Webb-Robertson
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA; Computing and Analytics Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Carmella Evans-Molina
- Center for Diabetes and Metabolic Diseases and the Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Raghavendra G Mirmira
- Center for Diabetes and Metabolic Diseases and the Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, USA.
| | - Thomas O Metz
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA.
| |
Collapse
|
9
|
Liu DC, Eagleman DE, Tsai NP. Novel roles of ER stress in repressing neural activity and seizures through Mdm2- and p53-dependent protein translation. PLoS Genet 2019; 15:e1008364. [PMID: 31557161 PMCID: PMC6762060 DOI: 10.1371/journal.pgen.1008364] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 08/08/2019] [Indexed: 12/30/2022] Open
Abstract
Seizures can induce endoplasmic reticulum (ER) stress, and sustained ER stress contributes to neuronal death after epileptic seizures. Despite the recent debate on whether inhibiting ER stress can reduce neuronal death after seizures, whether and how ER stress impacts neural activity and seizures remain unclear. In this study, we discovered that the acute ER stress response functions to repress neural activity through a protein translation-dependent mechanism. We found that inducing ER stress promotes the expression and distribution of murine double minute-2 (Mdm2) in the nucleus, leading to ubiquitination and down-regulation of the tumor suppressor p53. Reduction of p53 subsequently maintains protein translation, before the onset of translational repression seen during the latter phase of the ER stress response. Disruption of Mdm2 in an Mdm2 conditional knockdown (cKD) mouse model impairs ER stress-induced p53 down-regulation, protein translation, and reduction of neural activity and seizure severity. Importantly, these defects in Mdm2 cKD mice were restored by both pharmacological and genetic inhibition of p53 to mimic the inactivation of p53 seen during ER stress. Altogether, our study uncovered a novel mechanism by which neurons respond to acute ER stress. Further, this mechanism plays a beneficial role in reducing neural activity and seizure severity. These findings caution against inhibition of ER stress as a neuroprotective strategy for seizures, epilepsies, and other pathological conditions associated with excessive neural activity. One-third of epilepsy patients respond poorly to current anti-epileptic drugs. Thus, there is an urgent need to characterize cellular behavior during seizures, and the corresponding molecular mechanisms in order to develop better therapies. Seizures are known to induce ER stress but how the ER stress response functions to modulate seizure activity is unknown. Our study provides evidence to demonstrate a novel and beneficial role for the ER stress response in reducing neural activity and seizure severity. Mechanistically, we found that these beneficial effects are mediated by elevated protein translation, which is triggered by the activation of Mdm2-p53 signaling, during the early ER stress response. Our findings suggest that therapeutic attempts to reduce ER stress in epilepsies may result in worsening seizure activity and therefore caution against inhibition of ER stress as a neuroprotective strategy for epilepsies.
Collapse
Affiliation(s)
- Dai-Chi Liu
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Daphne E. Eagleman
- Department of Molecular and Integrative Physiology, School of Molecular and Cellular Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Nien-Pei Tsai
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Department of Molecular and Integrative Physiology, School of Molecular and Cellular Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- * E-mail:
| |
Collapse
|
10
|
Cnop M, Toivonen S, Igoillo-Esteve M, Salpea P. Endoplasmic reticulum stress and eIF2α phosphorylation: The Achilles heel of pancreatic β cells. Mol Metab 2017; 6:1024-1039. [PMID: 28951826 PMCID: PMC5605732 DOI: 10.1016/j.molmet.2017.06.001] [Citation(s) in RCA: 176] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 05/19/2017] [Accepted: 06/01/2017] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Pancreatic β cell dysfunction and death are central in the pathogenesis of most if not all forms of diabetes. Understanding the molecular mechanisms underlying β cell failure is important to develop β cell protective approaches. SCOPE OF REVIEW Here we review the role of endoplasmic reticulum stress and dysregulated endoplasmic reticulum stress signaling in β cell failure in monogenic and polygenic forms of diabetes. There is substantial evidence for the presence of endoplasmic reticulum stress in β cells in type 1 and type 2 diabetes. Direct evidence for the importance of this stress response is provided by an increasing number of monogenic forms of diabetes. In particular, mutations in the PERK branch of the unfolded protein response provide insight into its importance for human β cell function and survival. The knowledge gained from different rodent models is reviewed. More disease- and patient-relevant models, using human induced pluripotent stem cells differentiated into β cells, will further advance our understanding of pathogenic mechanisms. Finally, we review the therapeutic modulation of endoplasmic reticulum stress and signaling in β cells. MAJOR CONCLUSIONS Pancreatic β cells are sensitive to excessive endoplasmic reticulum stress and dysregulated eIF2α phosphorylation, as indicated by transcriptome data, monogenic forms of diabetes and pharmacological studies. This should be taken into consideration when devising new therapeutic approaches for diabetes.
Collapse
Key Words
- ATF, activating transcription factor
- CHOP, C/EBP homologous protein
- CRISPR, clustered regularly interspaced short palindromic repeats
- CReP, constitutive repressor of eIF2α phosphorylation
- Diabetes
- ER, endoplasmic reticulum
- ERAD, ER-associated degradation
- Endoplasmic reticulum stress
- GCN2, general control non-derepressible-2
- GIP, glucose-dependent insulinotropic polypeptide
- GLP-1, glucagon-like peptide 1
- GWAS, genome-wide association study
- HNF1A, hepatocyte nuclear factor 1-α
- HRI, heme-regulated inhibitor kinase
- IAPP, islet amyloid polypeptide
- IER3IP1, immediate early response-3 interacting protein-1
- IRE1, inositol-requiring protein-1
- ISR, integrated stress response
- Insulin
- Islet
- MEHMO, mental retardation, epilepsy, hypogonadism and -genitalism, microcephaly and obesity
- MODY, maturity-onset diabetes of the young
- NRF2, nuclear factor, erythroid 2 like 2
- PBA, 4-phenyl butyric acid
- PERK, PKR-like ER kinase
- PKR, protein kinase RNA
- PP1, protein phosphatase 1
- PPA, phenylpropenoic acid glucoside
- Pancreatic β cell
- Pdx1, pancreatic duodenal homeobox 1
- RIDD, regulated IRE1-dependent decay
- RyR2, type 2 ryanodine receptor/Ca2+ release channel
- SERCA, sarcoendoplasmic reticulum Ca2+ ATPase
- TUDCA, taurine-conjugated ursodeoxycholic acid derivative
- UPR, unfolded protein response
- WFS, Wolfram syndrome
- XBP1, X-box binding protein 1
- eIF2, eukaryotic translation initiation factor 2
- eIF2α
- hESC, human embryonic stem cell
- hPSC, human pluripotent stem cell
- hiPSC, human induced pluripotent stem cell
- uORF, upstream open reading frame
Collapse
Affiliation(s)
- Miriam Cnop
- ULB Center for Diabetes Research, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
- Division of Endocrinology, Erasmus Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | - Sanna Toivonen
- ULB Center for Diabetes Research, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
| | - Mariana Igoillo-Esteve
- ULB Center for Diabetes Research, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
| | - Paraskevi Salpea
- ULB Center for Diabetes Research, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium
| |
Collapse
|
11
|
Chronic high fat feeding restricts islet mRNA translation initiation independently of ER stress via DNA damage and p53 activation. Sci Rep 2017. [PMID: 28630491 PMCID: PMC5476640 DOI: 10.1038/s41598-017-03869-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Under conditions of high fat diet (HFD) consumption, glucose dyshomeostasis develops when β-cells are unable to adapt to peripheral insulin demands. Few studies have interrogated the molecular mechanisms of β-cell dysfunction at the level of mRNA translation under such conditions. We sought to address this issue through polyribosome profile analysis of islets from mice fed 16-weeks of 42% HFD. HFD-islet analysis revealed clear trends toward global reductions in mRNA translation with a significant reduction in the polyribosome/monoribosome ratio for Pdx1 mRNA. Transcriptional and translational analyses revealed endoplasmic reticulum stress was not the etiology of our findings. HFD-islets demonstrated evidence of oxidative stress and DNA damage, as well as activation of p53. Experiments in MIN-6 β-cells revealed that treatment with doxorubicin to directly induce DNA damage mimicked our observed effects in islets. Islets from animals treated with pioglitazone concurrently with HFD demonstrated a reversal of effects observed from HFD alone. Finally, HFD-islets demonstrated reduced expression of multiple ribosome biogenesis genes and the key translation initiation factor eIF4E. We propose a heretofore unappreciated effect of chronic HFD on β-cells, wherein continued DNA damage owing to persistent oxidative stress results in p53 activation and a resultant inhibition of mRNA translation.
Collapse
|
12
|
Abstract
The stress response and cell survival are necessary for normal pancreatic β-cell function, glucose homeostasis, and prevention of diabetes. The homeodomain transcription factor and human diabetes gene pancreas/duodenum homeobox protein 1 (Pdx1) regulates β-cell survival and endoplasmic reticulum stress susceptibility, in part through direct regulation of activating transcription factor 4 (Atf4). Here we show that Atf5, a close but less-studied relative of Atf4, is also a target of Pdx1 and is critical for β-cell survival under stress conditions. Pdx1 deficiency led to decreased Atf5 transcript, and primary islet ChIP-sequencing localized PDX1 to the Atf5 promoter, implicating Atf5 as a PDX1 target. Atf5 expression was stress inducible and enriched in β cells. Importantly, Atf5 deficiency decreased survival under stress conditions. Loss-of-function and chromatin occupancy experiments positioned Atf5 downstream of and parallel to Atf4 in the regulation of eIF4E-binding protein 1 (4ebp1), a mammalian target of rapamycin (mTOR) pathway component that inhibits protein translation. Accordingly, Atf5 deficiency attenuated stress suppression of global translation, likely enhancing the susceptibility of β cells to stress-induced apoptosis. Thus, we identify ATF5 as a member of the transcriptional network governing pancreatic β-cell survival during stress.
Collapse
|
13
|
Takatani T, Shirakawa J, Roe MW, Leech CA, Maier BF, Mirmira RG, Kulkarni RN. IRS1 deficiency protects β-cells against ER stress-induced apoptosis by modulating sXBP-1 stability and protein translation. Sci Rep 2016; 6:28177. [PMID: 27378176 PMCID: PMC4932502 DOI: 10.1038/srep28177] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 05/31/2016] [Indexed: 01/05/2023] Open
Abstract
Endoplasmic reticulum (ER) stress is among several pathological features that underlie β-cell failure in the development of type 1 and type 2 diabetes. Adaptor proteins in the insulin/insulin-like-growth factor-1 signaling pathways, such as insulin receptor substrate-1 (IRS1) and IRS2, differentially impact β-cell survival but the underlying mechanisms remain unclear. Here we report that β-cells deficient in IRS1 (IRS1KO) are resistant, while IRS2 deficiency (IRS2KO) makes them susceptible to ER stress-mediated apoptosis. IRS1KOs exhibited low nuclear accumulation of spliced XBP-1 due to its poor stability, in contrast to elevated accumulation in IRS2KO. The reduced nuclear accumulation in IRS1KO was due to protein instability of Xbp1 secondary to proteasomal degradation. IRS1KO also demonstrated an attenuation in their general translation status in response to ER stress revealed by polyribosomal profiling. Phosphorylation of eEF2 was dramatically increased in IRS1KO enabling the β-cells to adapt to ER stress by blocking translation. Furthermore, significantly high ER calcium (Ca2+) was detected in IRS1KO β-cells even upon induction of ER stress. These observations suggest that IRS1 could be a therapeutic target for β-cell protection against ER stress-mediated cell death by modulating XBP-1 stability, protein synthesis, and Ca2+ storage in the ER.
Collapse
Affiliation(s)
- Tomozumi Takatani
- Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital, Harvard Stem Cell Institute, Harvard Medical School, Boston, MA, USA
| | - Jun Shirakawa
- Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital, Harvard Stem Cell Institute, Harvard Medical School, Boston, MA, USA
| | - Michael W Roe
- Department of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, NY, USA
| | - Colin A Leech
- Department of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, NY, USA
| | - Bernhard F Maier
- Department of Pediatrics and Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Raghavendra G Mirmira
- Department of Pediatrics and Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, USA.,Department of Cellular and Integrative Physiology, Department of Biochemistry and Molecular Biology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Rohit N Kulkarni
- Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital, Harvard Stem Cell Institute, Harvard Medical School, Boston, MA, USA
| |
Collapse
|