1
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Nwosu BU, Parajuli S, Sharma RB, Lee AF. Effect of Ergocalciferol on β-Cell Function in New-Onset Type 1 Diabetes: A Secondary Analysis of a Randomized Clinical Trial. JAMA Netw Open 2024; 7:e241155. [PMID: 38441899 PMCID: PMC10915693 DOI: 10.1001/jamanetworkopen.2024.1155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 01/12/2024] [Indexed: 03/07/2024] Open
Abstract
This secondary analysis of a randomized clinical trial evaluates the effectiveness of ergocalciferol vs placebo in youths with newly diagnosed type 1 diabetes.
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Affiliation(s)
- Benjamin Udoka Nwosu
- Northwell Health, Division of Endocrinology, Department of Pediatrics, Cohen Children’s Medical Center, New Hyde Park, New York
- Division of Endocrinology, Department of Pediatrics, University of Massachusetts Medical School, Worcester
| | - Sadichchha Parajuli
- Division of Endocrinology, Department of Pediatrics, University of Massachusetts Medical School, Worcester
- Monroe Family Medicine Program, Louisiana State University Hospital, Shreveport
| | - Rohit B. Sharma
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Weill Cornell Medicine, New York, New York
| | - Austin F. Lee
- Department of Population and Quantitative Health Sciences, University of Massachusetts Chan Medical School, Worcester
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2
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Stamateris RE, Landa-Galvan HV, Sharma RB, Darko C, Redmond D, Rane SG, Alonso LC. Noncanonical CDK4 signaling rescues diabetes in a mouse model by promoting β cell differentiation. J Clin Invest 2023; 133:e166490. [PMID: 37712417 PMCID: PMC10503800 DOI: 10.1172/jci166490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 07/27/2023] [Indexed: 09/16/2023] Open
Abstract
Expanding β cell mass is a critical goal in the fight against diabetes. CDK4, an extensively characterized cell cycle activator, is required to establish and maintain β cell number. β cell failure in the IRS2-deletion mouse type 2 diabetes model is, in part, due to loss of CDK4 regulator cyclin D2. We set out to determine whether replacement of endogenous CDK4 with the inhibitor-resistant mutant CDK4-R24C rescued the loss of β cell mass in IRS2-deficient mice. Surprisingly, not only β cell mass but also β cell dedifferentiation was effectively rescued, despite no improvement in whole body insulin sensitivity. Ex vivo studies in primary islet cells revealed a mechanism in which CDK4 intervened downstream in the insulin signaling pathway to prevent FOXO1-mediated transcriptional repression of critical β cell transcription factor Pdx1. FOXO1 inhibition was not related to E2F1 activity, to FOXO1 phosphorylation, or even to FOXO1 subcellular localization, but rather was related to deacetylation and reduced FOXO1 abundance. Taken together, these results demonstrate a differentiation-promoting activity of the classical cell cycle activator CDK4 and support the concept that β cell mass can be expanded without compromising function.
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Affiliation(s)
- Rachel E. Stamateris
- MD/PhD Program, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Huguet V. Landa-Galvan
- Division of Endocrinology, Diabetes and Metabolism and the Joan and Sanford I. Weill Center for Metabolic Health and
| | - Rohit B. Sharma
- Division of Endocrinology, Diabetes and Metabolism and the Joan and Sanford I. Weill Center for Metabolic Health and
| | - Christine Darko
- Division of Endocrinology, Diabetes and Metabolism and the Joan and Sanford I. Weill Center for Metabolic Health and
| | - David Redmond
- Hartman Institute for Therapeutic Regenerative Medicine, Division of Regenerative Medicine, Department of Medicine, Weill Cornell Medicine, New York, New York, USA
| | - Sushil G. Rane
- Integrative Cellular Metabolism Section, Diabetes, Endocrinology and Obesity Branch, National Institute for Diabetes, Digestive and Kidney Diseases, NIH, Bethesda, Maryland, USA
| | - Laura C. Alonso
- Division of Endocrinology, Diabetes and Metabolism and the Joan and Sanford I. Weill Center for Metabolic Health and
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3
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Skovsø S, Panzhinskiy E, Kolic J, Cen HH, Dionne DA, Dai XQ, Sharma RB, Elghazi L, Ellis CE, Faulkner K, Marcil SAM, Overby P, Noursadeghi N, Hutchinson D, Hu X, Li H, Modi H, Wildi JS, Botezelli JD, Noh HL, Suk S, Gablaski B, Bautista A, Kim R, Cras-Méneur C, Flibotte S, Sinha S, Luciani DS, Nislow C, Rideout EJ, Cytrynbaum EN, Kim JK, Bernal-Mizrachi E, Alonso LC, MacDonald PE, Johnson JD. Beta-cell specific Insr deletion promotes insulin hypersecretion and improves glucose tolerance prior to global insulin resistance. Nat Commun 2022; 13:735. [PMID: 35136059 PMCID: PMC8826929 DOI: 10.1038/s41467-022-28039-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 01/05/2022] [Indexed: 01/23/2023] Open
Abstract
Insulin receptor (Insr) protein is present at higher levels in pancreatic β-cells than in most other tissues, but the consequences of β-cell insulin resistance remain enigmatic. Here, we use an Ins1cre knock-in allele to delete Insr specifically in β-cells of both female and male mice. We compare experimental mice to Ins1cre-containing littermate controls at multiple ages and on multiple diets. RNA-seq of purified recombined β-cells reveals transcriptomic consequences of Insr loss, which differ between female and male mice. Action potential and calcium oscillation frequencies are increased in Insr knockout β-cells from female, but not male mice, whereas only male βInsrKO islets have reduced ATP-coupled oxygen consumption rate and reduced expression of genes involved in ATP synthesis. Female βInsrKO and βInsrHET mice exhibit elevated insulin release in ex vivo perifusion experiments, during hyperglycemic clamps, and following i.p. glucose challenge. Deletion of Insr does not alter β-cell area up to 9 months of age, nor does it impair hyperglycemia-induced proliferation. Based on our data, we adapt a mathematical model to include β-cell insulin resistance, which predicts that β-cell Insr knockout improves glucose tolerance depending on the degree of whole-body insulin resistance. Indeed, glucose tolerance is significantly improved in female βInsrKO and βInsrHET mice compared to controls at 9, 21 and 39 weeks, and also in insulin-sensitive 4-week old males. We observe no improved glucose tolerance in older male mice or in high fat diet-fed mice, corroborating the prediction that global insulin resistance obscures the effects of β-cell specific insulin resistance. The propensity for hyperinsulinemia is associated with mildly reduced fasting glucose and increased body weight. We further validate our main in vivo findings using an Ins1-CreERT transgenic line and find that male mice have improved glucose tolerance 4 weeks after tamoxifen-mediated Insr deletion. Collectively, our data show that β-cell insulin resistance in the form of reduced β-cell Insr contributes to hyperinsulinemia in the context of glucose stimulation, thereby improving glucose homeostasis in otherwise insulin sensitive sex, dietary and age contexts.
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Affiliation(s)
- Søs Skovsø
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Evgeniy Panzhinskiy
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Jelena Kolic
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Haoning Howard Cen
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Derek A Dionne
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Xiao-Qing Dai
- Alberta Diabetes Institute and Department of Pharmacology, University of Alberta, Edmonton, Canada
| | - Rohit B Sharma
- Division of Endocrinology, Diabetes and Metabolism and the Weill Center for Metabolic Health, Weill Cornell Medicine, New York, NY, USA
| | - Lynda Elghazi
- Department of Ophthalmology and Visual Sciences, University of Michigan Kellogg Eye Center, Ann Arbor, MI, USA
| | - Cara E Ellis
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Katharine Faulkner
- Department of Mathematics, University of British Columbia, Vancouver, BC, Canada
| | - Stephanie A M Marcil
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Peter Overby
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Nilou Noursadeghi
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Daria Hutchinson
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Xiaoke Hu
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Hong Li
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Honey Modi
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Jennifer S Wildi
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - J Diego Botezelli
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Hye Lim Noh
- Program in Molecular Medicine University of Massachusetts Medical School, Worcester, MA, USA
- Charles River Laboratories, Shrewsbury, MA, USA
| | - Sujin Suk
- Program in Molecular Medicine University of Massachusetts Medical School, Worcester, MA, USA
| | - Brian Gablaski
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Massachusetts Medical School, Worcester, MA, USA
- Charles River Laboratories, Shrewsbury, MA, USA
| | - Austin Bautista
- Alberta Diabetes Institute and Department of Pharmacology, University of Alberta, Edmonton, Canada
| | - Ryekjang Kim
- Alberta Diabetes Institute and Department of Pharmacology, University of Alberta, Edmonton, Canada
| | - Corentin Cras-Méneur
- Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes, University of Michigan, Ann Arbor, MI, USA
| | - Stephane Flibotte
- UBC Life Sciences Institute Bioinformatics Facility, University of British Columbia, Vancouver, BC, Canada
| | - Sunita Sinha
- UBC Sequencing and Bioinformatics Consortium, Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Dan S Luciani
- BC Children's Hospital Research Institute, Department of Surgery, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Corey Nislow
- UBC Sequencing and Bioinformatics Consortium, Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Elizabeth J Rideout
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Eric N Cytrynbaum
- Department of Mathematics, University of British Columbia, Vancouver, BC, Canada
| | - Jason K Kim
- Program in Molecular Medicine University of Massachusetts Medical School, Worcester, MA, USA
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | - Ernesto Bernal-Mizrachi
- Division of Endocrinology, Diabetes and Metabolism, University of Miami Miller School of Medicine and Miami VA Health Care System, Miami, FL, USA
| | - Laura C Alonso
- Division of Endocrinology, Diabetes and Metabolism and the Weill Center for Metabolic Health, Weill Cornell Medicine, New York, NY, USA
| | - Patrick E MacDonald
- Alberta Diabetes Institute and Department of Pharmacology, University of Alberta, Edmonton, Canada
| | - James D Johnson
- Diabetes Research Group, Life Sciences Institute, and Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada.
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4
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Nwosu BU, Parajuli S, Jasmin G, Fleshman J, Sharma RB, Alonso LC, Lee AF, Barton BA. Ergocalciferol in New-onset Type 1 Diabetes: A Randomized Controlled Trial. J Endocr Soc 2022; 6:bvab179. [PMID: 34913020 PMCID: PMC8668202 DOI: 10.1210/jendso/bvab179] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Indexed: 01/15/2023] Open
Abstract
Context The effect of the anti-inflammatory and immunomodulatory actions of vitamin D on the duration of partial clinical remission (PR) in youth with type 1 diabetes (T1D) is unclear. Objective This work aimed to determine the effect of adjunctive ergocalciferol on residual β-cell function (RBCF) and PR in youth with newly diagnosed T1D who were maintained on a standardized insulin treatment protocol. The hypothesis was that ergocalciferol supplementation increases RBCF and prolongs PR. Methods A 12-month, randomized, double-blind, placebo-controlled trial was conducted of 50 000 IU of ergocalciferol per week for 2 months, and then once every 2 weeks for 10 months, vs placebo in 36 individuals aged 10 to 21 years, with T1D of less than 3 months and a stimulated C-peptide (SCP) level greater than or equal to 0.2 nmol/L (≥ 0.6 ng/mL). The ergocalciferol group had 18 randomly assigned participants (10 male/8 female), mean age 13.3 ± 2.8 years, while the control group had 18 participants (14 male/4 female), aged 14.3 ± 2.9 years. Results The ergocalciferol treatment group had statistically significantly higher serum 25-hydroxyvitamin D at 6 months (P = .01) and 9 months (P = .02) than the placebo group. At 12 months, the ergocalciferol group had a statistically significantly lower serum tumor necrosis factor α (TNF-α) concentration (P = .03). There were no statistically significant differences between the groups at each time point from baseline to 12 months for SCP concentration (P = .08), glycated hemoglobin A1c (HbA1c) (P = .09), insulin dose-adjusted A1c (IDAA1c), or total daily dose of insulin. Temporal trends for rising HbA1c (P = .04) and IDAA1c (P = .02) were statistically significantly blunted in the ergocalciferol group. Conclusion Ergocalciferol statistically significantly reduced serum TNF-α concentration and the rates of increase both in A1c and IDAA1c, suggesting a protection of RBCF and PR in youth with newly diagnosed T1D.
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Affiliation(s)
- Benjamin Udoka Nwosu
- Division of Pediatric Endocrinology, Department of Pediatrics, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
| | - Sadichchha Parajuli
- Division of Pediatric Endocrinology, Department of Pediatrics, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
| | - Gabrielle Jasmin
- Division of Pediatric Endocrinology, Department of Pediatrics, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
| | - Jody Fleshman
- Division of Pediatric Endocrinology, Department of Pediatrics, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
| | - Rohit B Sharma
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Weill Cornell Medicine, New York, New York, USA
| | - Laura C Alonso
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Weill Cornell Medicine, New York, New York, USA
| | - Austin F Lee
- Department of Population and Quantitative Health Sciences, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
| | - Bruce A Barton
- Department of Population and Quantitative Health Sciences, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
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5
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Abstract
Type 2 diabetes (T2D) is a growing cause of poor health, psychosocial burden, and economic costs worldwide. The pancreatic β-cell is a cornerstone of metabolic physiology. Insulin deficiency leads to hyperglycemia, which was fatal before the availability of therapeutic insulins; even partial deficiency of insulin leads to diabetes in the context of insulin resistance. Comprising only an estimated 1 g or <1/500th of a percent of the human body mass, pancreatic β-cells of the islets of Langerhans are a vulnerable link in metabolism. Proinsulin production constitutes a major load on β-cell endoplasmic reticulum (ER), and decompensated ER stress is a cause of β-cell failure and loss in both type 1 diabetes (T1D) and T2D. The unfolded protein response (UPR), the principal ER stress response system, is critical for maintenance of β-cell health. Successful UPR guides expansion of ER protein folding capacity and increased β-cell number through survival pathways and cell replication. However, in some cases the ER stress response can cause collateral β-cell damage and may even contribute to diabetes pathogenesis. Here we review the known beneficial and harmful effects of UPR pathways in pancreatic β-cells. Improved understanding of this stress response tipping point may lead to approaches to maintain β-cell health and function.
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Affiliation(s)
- Rohit B Sharma
- Division of Endocrinology, Diabetes and Metabolism and Weill Center for Metabolic Health, Weill Cornell Medicine, New York, NY
| | - Huguet V Landa-Galván
- Division of Endocrinology, Diabetes and Metabolism and Weill Center for Metabolic Health, Weill Cornell Medicine, New York, NY
| | - Laura C Alonso
- Division of Endocrinology, Diabetes and Metabolism and Weill Center for Metabolic Health, Weill Cornell Medicine, New York, NY
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Snyder JT, Darko C, Sharma RB, Alonso LC. Endoplasmic Reticulum Stress Induced Proliferation Remains Intact in Aging Mouse β-Cells. Front Endocrinol (Lausanne) 2021; 12:734079. [PMID: 34531828 PMCID: PMC8438540 DOI: 10.3389/fendo.2021.734079] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 08/05/2021] [Indexed: 02/06/2023] Open
Abstract
Aging is associated with loss of proliferation of the insulin-secreting β-cell, a possible contributing factor to the increased prevalence of type 2 diabetes in the elderly. Our group previously discovered that moderate endoplasmic reticulum (ER) stress occurring during glucose exposure increases the adaptive β-cell proliferation response. Specifically, the ATF6α arm of the tripartite Unfolded Protein Response (UPR) promotes β-cell replication in glucose excess conditions. We hypothesized that β-cells from older mice have reduced proliferation due to aberrant UPR signaling or an impaired proliferative response to ER stress or ATF6α activation. To investigate, young and old mouse islet cells were exposed to high glucose with low-dose thapsigargin or activation of overexpressed ATF6α, and β-cell proliferation was quantified by BrdU incorporation. UPR pathway activation was compared by qPCR of target genes and semi-quantitative Xbp1 splicing assay. Intriguingly, although old β-cells had reduced proliferation in high glucose compared to young β-cells, UPR activation and induction of proliferation in response to low-dose thapsigargin or ATF6α activation in high glucose were largely similar between young and old. These results suggest that loss of UPR-led adaptive proliferation does not explain the reduced cell cycle entry in old β-cells, and raise the exciting possibility that future therapies that engage adaptive UPR could increase β-cell number through proliferation even in older individuals.
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Affiliation(s)
- Jarin T. Snyder
- Graduate School of Biomedical Sciences, UMass Medical School, Worcester, MA, United States
| | - Christine Darko
- Division of Endocrinology, Diabetes and Metabolism and the Weill Center for Metabolic Health, Weill Cornell Medicine, New York, NY, United States
| | - Rohit B. Sharma
- Division of Endocrinology, Diabetes and Metabolism and the Weill Center for Metabolic Health, Weill Cornell Medicine, New York, NY, United States
| | - Laura C. Alonso
- Division of Endocrinology, Diabetes and Metabolism and the Weill Center for Metabolic Health, Weill Cornell Medicine, New York, NY, United States
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Charbord J, Ren L, Sharma RB, Johansson A, Ågren R, Chu L, Tworus D, Schulz N, Charbord P, Stewart AF, Wang P, Alonso LC, Andersson O. In vivo screen identifies a SIK inhibitor that induces β cell proliferation through a transient UPR. Nat Metab 2021; 3:682-700. [PMID: 34031592 PMCID: PMC9756392 DOI: 10.1038/s42255-021-00391-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 04/14/2021] [Indexed: 02/03/2023]
Abstract
It is known that β cell proliferation expands the β cell mass during development and under certain hyperglycemic conditions in the adult, a process that may be used for β cell regeneration in diabetes. Here, through a new high-throughput screen using a luminescence ubiquitination-based cell cycle indicator (LUCCI) in zebrafish, we identify HG-9-91-01 as a driver of proliferation and confirm this effect in mouse and human β cells. HG-9-91-01 is an inhibitor of salt-inducible kinases (SIKs), and overexpression of Sik1 specifically in β cells blocks the effect of HG-9-91-01 on β cell proliferation. Single-cell transcriptomic analyses of mouse β cells demonstrate that HG-9-91-01 induces a wave of activating transcription factor (ATF)6-dependent unfolded protein response (UPR) before cell cycle entry. Importantly, the UPR wave is not associated with an increase in insulin expression. Additional mechanistic studies indicate that HG-9-91-01 induces multiple signalling effectors downstream of SIK inhibition, including CRTC1, CRTC2, ATF6, IRE1 and mTOR, which integrate to collectively drive β cell proliferation.
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Affiliation(s)
- Jérémie Charbord
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Lipeng Ren
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Rohit B Sharma
- Division of Endocrinology, Diabetes and Metabolism, Weill Cornell Medicine, New York, NY, USA
| | - Anna Johansson
- Department of Cell and Molecular Biology, National Bioinformatics Infrastructure Sweden, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Rasmus Ågren
- Department of Biology and Biological Engineering, National Bioinformatics Infrastructure Sweden, Science for Life Laboratory, Chalmers University of Technology, Göteborg, Sweden
| | - Lianhe Chu
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Dominika Tworus
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Nadja Schulz
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Pierre Charbord
- Sorbonne Université, Institut de Biologie Paris-Seine, CNRS UMR 7622, Inserm, Paris, France
| | - Andrew F Stewart
- Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Peng Wang
- Diabetes, Obesity, and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Laura C Alonso
- Division of Endocrinology, Diabetes and Metabolism, Weill Cornell Medicine, New York, NY, USA
| | - Olov Andersson
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden.
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Sharma RB, Darko C, Alonso LC. Intersection of the ATF6 and XBP1 ER stress pathways in mouse islet cells. J Biol Chem 2020; 295:14164-14177. [PMID: 32788214 DOI: 10.1074/jbc.ra120.014173] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 08/06/2020] [Indexed: 12/20/2022] Open
Abstract
Success or failure of pancreatic beta cell adaptation to ER stress is a determinant of diabetes susceptibility. The ATF6 and IRE1/XBP1 pathways are separate ER stress-response effectors important to beta cell health and function. ATF6α. and XBP1 direct overlapping transcriptional responses in some cell types. However, the signaling dynamics and interdependence of ATF6α and XBP1 in pancreatic beta cells have not been explored. To assess pathway-specific signal onset, we performed timed exposures of primary mouse islet cells to ER stressors and measured the early transcriptional response. Comparing the time course of induction of ATF6 and XBP1 targets suggested that the two pathways have similar response dynamics. The role of ATF6α in target induction was assessed by acute knockdown using islet cells from Atf6α flox/flox mice transduced with adenovirus expressing Cre recombinase. Surprisingly, given the mild impact of chronic deletion in mice, acute ATF6α knockdown markedly reduced ATF6-pathway target gene expression under both basal and stressed conditions. Intriguingly, although ATF6α knockdown did not alter Xbp1 splicing dynamics or intensity, it did reduce induction of XBP1 targets. Inhibition of Xbp1 splicing did not decrease induction of ATF6α targets. Taken together, these data suggest that the XBP1 and ATF6 pathways are simultaneously activated in islet cells in response to acute stress and that ATF6α is required for full activation of XBP1 targets, but XBP1 is not required for activation of ATF6α targets. These observations improve understanding of the ER stress transcriptional response in pancreatic islets.
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Affiliation(s)
- Rohit B Sharma
- Division of Endocrinology, Diabetes and Metabolism, Weill Cornell Medicine, New York, New York, USA .,Weill Center for Metabolic Health, Weill Cornell Medicine, New York, New York, USA
| | - Christine Darko
- Division of Endocrinology, Diabetes and Metabolism, Weill Cornell Medicine, New York, New York, USA.,Weill Center for Metabolic Health, Weill Cornell Medicine, New York, New York, USA
| | - Laura C Alonso
- Division of Endocrinology, Diabetes and Metabolism, Weill Cornell Medicine, New York, New York, USA .,Weill Center for Metabolic Health, Weill Cornell Medicine, New York, New York, USA
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9
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Abstract
Background A growing body of literature suggests the cell–intrinsic activity of Atf6α during ER stress responses has implications for tissue cell number during growth and development, as well as in adult biology and tumorigenesis [1]. This concept is important, linking the cellular processes of secretory protein synthesis and endoplasmic reticulum stress response with functional tissue capacity and organ size. However, the field contains conflicting observations, especially notable in secretory cell types like the pancreatic beta cell. Scope of review Here we summarize current knowledge of the basic biology of Atf6α, along with the pleiotropic roles Atf6α plays in cell life and death decisions and possible explanations for conflicting observations. We include studies investigating the roles of Atf6α in cell survival, death and proliferation using well-controlled methodology and specific validated outcome measures, with a focus on endocrine and metabolic tissues when information was available. Major conclusions The net outcome of Atf6α on cell survival and cell death depends on cell type and growth conditions, the presence and degree of ER stress, and the duration and intensity of Atf6α activation. It is unquestioned that Atf6α activity influences the cell fate decision between survival and death, although opposite directions of this outcome are reported in different contexts. Atf6α can also trigger cell cycle activity to expand tissue cell number through proliferation. Much work remains to be done to clarify the many gaps in understanding in this important emerging field.
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Affiliation(s)
- Rohit B Sharma
- Diabetes Center of Excellence, Department of Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | - Jarin T Snyder
- Diabetes Center of Excellence, Department of Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | - Laura C Alonso
- Diabetes Center of Excellence, Department of Medicine, University of Massachusetts Medical School, Worcester, MA, USA.
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10
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Pawaria S, Nündel K, Gao KM, Moses S, Busto P, Holt K, Sharma RB, Brehm MA, Gravallese EM, Socolovsky M, Christ A, Marshak-Rothstein A. Role of Interferon-γ-Producing Th1 Cells in a Murine Model of Type I Interferon-Independent Autoinflammation Resulting From DNase II Deficiency. Arthritis Rheumatol 2019; 72:359-370. [PMID: 31464028 DOI: 10.1002/art.41090] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 08/22/2019] [Indexed: 01/13/2023]
Abstract
OBJECTIVE Patients with hypomorphic mutations in DNase II develop a severe and debilitating autoinflammatory disease. This study was undertaken to compare the disease parameters in these patients to those in a murine model of DNase II deficiency, and to evaluate the role of specific nucleic acid sensors and identify the cell types responsible for driving the autoinflammatory response. METHODS To avoid embryonic death, Dnase2-/- mice were intercrossed with mice that lacked the type I interferon (IFN) receptor (Ifnar-/- ). The hematologic changes and immune status of these mice were evaluated using complete blood cell counts, flow cytometry, serum cytokine enzyme-linked immunosorbent assays, and liver histology. Effector cell activity was determined by transferring T cells from Dnase2-/- × Ifnar-/- double-knockout (DKO) mice into Rag1-/- mice, and 4 weeks after cell transfer, induced changes were assessed in the recipient mice. RESULTS In Dnase2-/- × Ifnar-/- DKO mice, many of the disease features found in DNase II-deficient patients were recapitulated, including cytopenia, extramedullary hematopoiesis, and liver fibrosis. Dnase2+/+ × Rag1-/- mice (n > 22) developed a hematologic disorder that was attributed to the transfer of an unusual IFNγ-producing T cell subset from the spleens of donor Dnase2-/- × Ifnar-/- DKO mice. Autoinflammation in this murine model did not depend on the stimulator of IFN genes (STING) pathway but was highly dependent on the chaperone protein Unc93B1. CONCLUSION Dnase2-/- × Ifnar-/- DKO mice may be a valid model for exploring the innate and adaptive immune mechanisms responsible for the autoinflammation similar to that seen in DNASE2-hypomorphic patients. In this murine model, IFNγ is required for T cell activation and the development of clinical manifestations. The role of IFNγ in DNASE2-deficient patient populations remains to be determined, but the ability of Dnase2-/- mouse T cells to transfer disease to Rag1-/- mice suggests that T cells may be a relevant therapeutic target in patients with IFN-related systemic autoinflammatory diseases.
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Affiliation(s)
| | | | - Kevin M Gao
- University of Massachusetts Medical School, Worcester
| | | | | | - Kevin Holt
- University of Massachusetts Medical School, Worcester
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11
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Abstract
Pancreatic β-cell regeneration, the therapeutic expansion of β-cell number to reverse diabetes, is an important goal. Replication of differentiated insulin-producing cells is the major source of new β-cells in adult mice and juvenile humans. Nucleoside analogs such as BrdU, which are incorporated into DNA during S-phase, have been widely used to quantify β-cell proliferation. However, reports of β-cell nuclei labeling with both BrdU and γ-phosphorylated H2A histone family member X (γH2AX), a DNA damage marker, have raised questions about the fidelity of BrdU to label S-phase, especially during conditions when DNA damage is present. We performed experiments to clarify the causes of BrdU-γH2AX double labeling in mouse and human β-cells. BrdU-γH2AX colabeling is neither an age-related phenomenon nor limited to human β-cells. DNA damage suppressed BrdU labeling and BrdU-γH2AX colabeling. In dispersed islet cells, but not in intact islets or in vivo, pro-proliferative conditions promoted both BrdU and γH2AX labeling, which could indicate DNA damage, DNA replication stress, or cell cycle-related intrinsic H2AX phosphorylation. Strategies to increase β-cell number must not only tackle the difficult challenge of enticing a quiescent cell to enter the cell cycle, but also achieve safe completion of the cell division process.
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Affiliation(s)
- Rohit B Sharma
- Diabetes Center of Excellence in the Department of Medicine, University of Massachusetts Medical School, Worcester, MA
| | - Christine Darko
- Diabetes Center of Excellence in the Department of Medicine, University of Massachusetts Medical School, Worcester, MA
| | - Xiaoying Zheng
- Diabetes Center of Excellence in the Department of Medicine, University of Massachusetts Medical School, Worcester, MA
| | - Brian Gablaski
- Diabetes Center of Excellence in the Department of Medicine, University of Massachusetts Medical School, Worcester, MA
| | - Laura C Alonso
- Diabetes Center of Excellence in the Department of Medicine, University of Massachusetts Medical School, Worcester, MA
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12
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Kong Y, Sharma RB, Ly S, Stamateris RE, Jesdale WM, Alonso LC. CDKN2A/B T2D Genome-Wide Association Study Risk SNPs Impact Locus Gene Expression and Proliferation in Human Islets. Diabetes 2018; 67:872-884. [PMID: 29432124 PMCID: PMC5910004 DOI: 10.2337/db17-1055] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 01/29/2018] [Indexed: 12/18/2022]
Abstract
Genome-wide association studies link the CDKN2A/B locus with type 2 diabetes (T2D) risk, but mechanisms increasing risk remain unknown. The CDKN2A/B locus encodes cell cycle inhibitors p14, p15, and p16; MTAP; and ANRIL, a long noncoding RNA. The goal of this study was to determine whether CDKN2A/B T2D risk SNPs impact locus gene expression, insulin secretion, or β-cell proliferation in human islets. Islets from donors without diabetes (n = 95) were tested for SNP genotype (rs10811661, rs2383208, rs564398, and rs10757283), gene expression (p14, p15, p16, MTAP, ANRIL, PCNA, KI67, and CCND2), insulin secretion (n = 61), and β-cell proliferation (n = 47). Intriguingly, locus genes were coregulated in islets in two physically overlapping cassettes: p14-p16-ANRIL, which increased with age, and MTAP-p15, which did not. Risk alleles at rs10811661 and rs2383208 were differentially associated with expression of ANRIL, but not p14, p15, p16, or MTAP, in age-dependent fashion, such that younger homozygous risk donors had higher ANRIL expression, equivalent to older donor levels. We identified several risk SNP combinations that may impact locus gene expression, suggesting possible mechanisms by which SNPs impact locus biology. Risk allele carriers at ANRIL coding SNP rs564398 had reduced β-cell proliferation index. In conclusion, CDKN2A/B locus SNPs may impact T2D risk by modulating islet gene expression and β-cell proliferation.
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Affiliation(s)
- Yahui Kong
- Diabetes Center of Excellence, Department of Medicine, University of Massachusetts Medical School, Worcester, MA
| | - Rohit B Sharma
- Diabetes Center of Excellence, Department of Medicine, University of Massachusetts Medical School, Worcester, MA
| | - Socheata Ly
- Diabetes Center of Excellence, Department of Medicine, University of Massachusetts Medical School, Worcester, MA
| | - Rachel E Stamateris
- Diabetes Center of Excellence, Department of Medicine, University of Massachusetts Medical School, Worcester, MA
| | - William M Jesdale
- Department of Quantitative Health Sciences, University of Massachusetts Medical School, Worcester, MA
| | - Laura C Alonso
- Diabetes Center of Excellence, Department of Medicine, University of Massachusetts Medical School, Worcester, MA
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13
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Abstract
Type 2 diabetes, fuelled by the obesity epidemic, is an escalating worldwide cause of personal hardship and public cost. Diabetes incidence increases with age, and many studies link the classic senescence and ageing protein p16(INK4A) to diabetes pathophysiology via pancreatic islet biology. Genome-wide association studies (GWASs) have unequivocally linked the CDKN2A/B locus, which encodes p16 inhibitor of cyclin-dependent kinase (p16(INK4A)) and three other gene products, p14 alternate reading frame (p14(ARF)), p15(INK4B) and antisense non-coding RNA in the INK4 locus (ANRIL), with human diabetes risk. However, the mechanism by which the CDKN2A/B locus influences diabetes risk remains uncertain. Here, we weigh the evidence that CDKN2A/B polymorphisms impact metabolic health via islet biology vs effects in other tissues. Structured in a bedside-to-bench-to-bedside approach, we begin with a summary of the evidence that the CDKN2A/B locus impacts diabetes risk and a brief review of the basic biology of CDKN2A/B gene products. The main emphasis of this work is an in-depth look at the nuanced roles that CDKN2A/B gene products and related proteins play in the regulation of beta cell mass, proliferation and insulin secretory function, as well as roles in other metabolic tissues. We finish with a synthesis of basic biology and clinical observations, incorporating human physiology data. We conclude that it is likely that the CDKN2A/B locus influences diabetes risk through both islet and non-islet mechanisms.
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Affiliation(s)
- Yahui Kong
- AS7-2047, Division of Diabetes, Department of Medicine, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01605, USA
| | - Rohit B Sharma
- AS7-2047, Division of Diabetes, Department of Medicine, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01605, USA
| | - Benjamin U Nwosu
- Division of Endocrinology, Department of Pediatrics, University of Massachusetts Medical School, Worcester, MA, USA
| | - Laura C Alonso
- AS7-2047, Division of Diabetes, Department of Medicine, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01605, USA.
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14
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Roth Flach RJ, Danai LV, DiStefano MT, Kelly M, Menendez LG, Jurczyk A, Sharma RB, Jung DY, Kim JH, Kim JK, Bortell R, Alonso LC, Czech MP. Protein Kinase Mitogen-activated Protein Kinase Kinase Kinase Kinase 4 (MAP4K4) Promotes Obesity-induced Hyperinsulinemia. J Biol Chem 2016; 291:16221-30. [PMID: 27226575 PMCID: PMC4965570 DOI: 10.1074/jbc.m116.718932] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Revised: 05/17/2016] [Indexed: 01/01/2023] Open
Abstract
Previous studies revealed a paradox whereby mitogen-activated protein kinase kinase kinase kinase 4 (Map4k4) acted as a negative regulator of insulin sensitivity in chronically obese mice, yet systemic deletion of Map4k4 did not improve glucose tolerance. Here, we report markedly reduced glucose-responsive plasma insulin and C-peptide levels in whole body Map4k4-depleted mice (M4K4 iKO) as well as an impaired first phase of insulin secretion from islets derived from M4K4 iKO mice ex vivo After long-term high fat diet (HFD), M4K4 iKO mice pancreata also displayed reduced β cell mass, fewer proliferating β cells and reduced islet-specific gene mRNA expression compared with controls, although insulin content was normal. Interestingly, the reduced plasma insulin in M4K4 iKO mice exposed to chronic (16 weeks) HFD was not observed in response to acute HFD challenge or short term treatment with the insulin receptor antagonist S961. Furthermore, the improved insulin sensitivity in obese M4K4 iKO mice was abrogated by high exogenous insulin over the course of a euglycemic clamp study, indicating that hypoinsulinemia promotes insulin sensitivity in chronically obese M4K4 iKO mice. These results demonstrate that protein kinase Map4k4 drives obesity-induced hyperinsulinemia and insulin resistance in part by promoting insulin secretion from β cells in mice.
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Affiliation(s)
| | | | | | - Mark Kelly
- Division of Cardiovascular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | | | | | - Rohit B Sharma
- Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, and
| | | | | | - Jason K Kim
- From the Program in Molecular Medicine, Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, and
| | | | - Laura C Alonso
- Department of Medicine, Division of Endocrinology, Metabolism and Diabetes, and
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15
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Choudhury SR, Fitzpatrick Z, Harris AF, Maitland SA, Ferreira JS, Zhang Y, Ma S, Sharma RB, Gray-Edwards HL, Johnson JA, Johnson AK, Alonso LC, Punzo C, Wagner KR, Maguire CA, Kotin RM, Martin DR, Sena-Esteves M. In Vivo Selection Yields AAV-B1 Capsid for Central Nervous System and Muscle Gene Therapy. Mol Ther 2016; 24:1247-57. [PMID: 27117222 DOI: 10.1038/mt.2016.84] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 04/12/2016] [Indexed: 12/12/2022] Open
Abstract
Adeno-associated viral (AAV) vectors have shown promise as a platform for gene therapy of neurological disorders. Achieving global gene delivery to the central nervous system (CNS) is key for development of effective therapies for many of these diseases. Here we report the isolation of a novel CNS tropic AAV capsid, AAV-B1, after a single round of in vivo selection from an AAV capsid library. Systemic injection of AAV-B1 vector in adult mice and cat resulted in widespread gene transfer throughout the CNS with transduction of multiple neuronal subpopulations. In addition, AAV-B1 transduces muscle, β-cells, pulmonary alveoli, and retinal vasculature at high efficiency. This vector is more efficient than AAV9 for gene delivery to mouse brain, spinal cord, muscle, pancreas, and lung. Together with reduced sensitivity to neutralization by antibodies in pooled human sera, the broad transduction profile of AAV-B1 represents an important improvement over AAV9 for CNS gene therapy.
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Affiliation(s)
- Sourav R Choudhury
- Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts, USA.,Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Zachary Fitzpatrick
- Department of Neurology, Massachusetts General Hospital and Program in Neuroscience, Harvard Medical School, Boston, Massachusetts, USA
| | - Anne F Harris
- Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts, USA.,Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Stacy A Maitland
- Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts, USA.,Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Jennifer S Ferreira
- Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts, USA.,Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Yuanfan Zhang
- The Hugo W. Moser Research Institute, Kennedy Krieger Institute and Departments of Neurology and Neuroscience, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Shan Ma
- Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts, USA.,Department of Ophthalmology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Rohit B Sharma
- Diabetes Center of Excellence, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Heather L Gray-Edwards
- Scott-Ritchey Research Center, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
| | - Jacob A Johnson
- Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
| | - Aime K Johnson
- Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
| | - Laura C Alonso
- Diabetes Center of Excellence, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Claudio Punzo
- Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts, USA.,Department of Ophthalmology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Kathryn R Wagner
- The Hugo W. Moser Research Institute, Kennedy Krieger Institute and Departments of Neurology and Neuroscience, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Casey A Maguire
- Department of Neurology, Massachusetts General Hospital and Program in Neuroscience, Harvard Medical School, Boston, Massachusetts, USA
| | - Robert M Kotin
- Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts, USA.,Voyager Therapeutics, Cambridge, Massachusetts, USA
| | - Douglas R Martin
- Scott-Ritchey Research Center, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA.,Department of Anatomy, Physiology & Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA
| | - Miguel Sena-Esteves
- Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts, USA.,Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts, USA
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16
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Stamateris RE, Sharma RB, Kong Y, Ebrahimpour P, Panday D, Ranganath P, Zou B, Levitt H, Parambil NA, O'Donnell CP, García-Ocaña A, Alonso LC. Glucose Induces Mouse β-Cell Proliferation via IRS2, MTOR, and Cyclin D2 but Not the Insulin Receptor. Diabetes 2016; 65:981-95. [PMID: 26740601 PMCID: PMC5314707 DOI: 10.2337/db15-0529] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2015] [Accepted: 12/29/2015] [Indexed: 12/21/2022]
Abstract
An important goal in diabetes research is to understand the processes that trigger endogenous β-cell proliferation. Hyperglycemia induces β-cell replication, but the mechanism remains debated. A prime candidate is insulin, which acts locally through the insulin receptor. Having previously developed an in vivo mouse hyperglycemia model, we tested whether glucose induces β-cell proliferation through insulin signaling. By using mice lacking insulin signaling intermediate insulin receptor substrate 2 (IRS2), we confirmed that hyperglycemia-induced β-cell proliferation requires IRS2 both in vivo and ex vivo. Of note, insulin receptor activation was not required for glucose-induced proliferation, and insulin itself was not sufficient to drive replication. Glucose and insulin caused similar acute signaling in mouse islets, but chronic signaling differed markedly, with mammalian target of rapamycin (MTOR) and extracellular signal-related kinase (ERK) activation by glucose and AKT activation by insulin. MTOR but not ERK activation was required for glucose-induced proliferation. Cyclin D2 was necessary for glucose-induced β-cell proliferation. Cyclin D2 expression was reduced when either IRS2 or MTOR signaling was lost, and restoring cyclin D2 expression rescued the proliferation defect. Human islets shared many of these regulatory pathways. Taken together, these results support a model in which IRS2, MTOR, and cyclin D2, but not the insulin receptor, mediate glucose-induced proliferation.
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Affiliation(s)
- Rachel E Stamateris
- Diabetes Center of Excellence, Department of Medicine, University of Massachusetts Medical School, Worcester, MA
| | - Rohit B Sharma
- Diabetes Center of Excellence, Department of Medicine, University of Massachusetts Medical School, Worcester, MA
| | - Yahui Kong
- Diabetes Center of Excellence, Department of Medicine, University of Massachusetts Medical School, Worcester, MA
| | - Pantea Ebrahimpour
- Diabetes Center of Excellence, Department of Medicine, University of Massachusetts Medical School, Worcester, MA
| | - Deepika Panday
- Diabetes Center of Excellence, Department of Medicine, University of Massachusetts Medical School, Worcester, MA
| | - Pavana Ranganath
- Diabetes Center of Excellence, Department of Medicine, University of Massachusetts Medical School, Worcester, MA
| | - Baobo Zou
- Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Helena Levitt
- Division of Endocrinology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | | | - Christopher P O'Donnell
- Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Adolfo García-Ocaña
- Diabetes, Obesity and Metabolism Institute, Division of Endocrinology, Diabetes and Bone Disease, The Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Laura C Alonso
- Diabetes Center of Excellence, Department of Medicine, University of Massachusetts Medical School, Worcester, MA
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17
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Sharma RB, O'Donnell AC, Stamateris RE, Ha B, McCloskey KM, Reynolds PR, Arvan P, Alonso LC. Insulin demand regulates β cell number via the unfolded protein response. J Clin Invest 2015; 125:3831-46. [PMID: 26389675 DOI: 10.1172/jci79264] [Citation(s) in RCA: 153] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 08/13/2015] [Indexed: 12/11/2022] Open
Abstract
Although stem cell populations mediate regeneration of rapid turnover tissues, such as skin, blood, and gut, a stem cell reservoir has not been identified for some slower turnover tissues, such as the pancreatic islet. Despite lacking identifiable stem cells, murine pancreatic β cell number expands in response to an increase in insulin demand. Lineage tracing shows that new β cells are generated from proliferation of mature, differentiated β cells; however, the mechanism by which these mature cells sense systemic insulin demand and initiate a proliferative response remains unknown. Here, we identified the β cell unfolded protein response (UPR), which senses insulin production, as a regulator of β cell proliferation. Using genetic and physiologic models, we determined that among the population of β cells, those with an active UPR are more likely to proliferate. Moreover, subthreshold endoplasmic reticulum stress (ER stress) drove insulin demand-induced β cell proliferation, through activation of ATF6. We also confirmed that the UPR regulates proliferation of human β cells, suggesting that therapeutic UPR modulation has potential to expand β cell mass in people at risk for diabetes. Together, this work defines a stem cell-independent model of tissue homeostasis, in which differentiated secretory cells use the UPR sensor to adapt organ size to meet demand.
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18
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Abstract
Free fatty acids (FFAs) exert both positive and negative effects on beta cell survival and insulin secretory function, depending on concentration, duration, and glucose abundance. Lipid signals are mediated not only through metabolic pathways, but also through cell surface and nuclear receptors. Toxicity is modulated by positive signals arising from circulating factors such as hormones, growth factors and incretins, as well as negative signals such as inflammatory mediators and cytokines. Intracellular mechanisms of lipotoxicity include metabolic interference and cellular stress responses such as oxidative stress, endoplasmic reticulum (ER) stress, and possibly autophagy. New findings strengthen an old hypothesis that lipids may also impair compensatory beta cell proliferation. Clinical observations continue to support a role for lipid biology in the risk and progression of both type 1 (T1D) and type 2 diabetes (T2D). This review summarizes recent work in this important, rapidly evolving field.
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Affiliation(s)
- Rohit B Sharma
- Diabetes Center of Excellence, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA, 01605, USA
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19
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Stamateris RE, Sharma RB, Hollern DA, Alonso LC. Adaptive β-cell proliferation increases early in high-fat feeding in mice, concurrent with metabolic changes, with induction of islet cyclin D2 expression. Am J Physiol Endocrinol Metab 2013; 305:E149-59. [PMID: 23673159 PMCID: PMC3725565 DOI: 10.1152/ajpendo.00040.2013] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Accepted: 05/10/2013] [Indexed: 01/09/2023]
Abstract
Type 2 diabetes (T2D) is caused by relative insulin deficiency, due in part to reduced β-cell mass (11, 62). Therapies aimed at expanding β-cell mass may be useful to treat T2D (14). Although feeding rodents a high-fat diet (HFD) for an extended period (3-6 mo) increases β-cell mass by inducing β-cell proliferation (16, 20, 53, 54), evidence suggests that adult human β-cells may not meaningfully proliferate in response to obesity. The timing and identity of the earliest initiators of the rodent compensatory growth response, possible therapeutic targets to drive proliferation in refractory human β-cells, are not known. To develop a model to identify early drivers of β-cell proliferation, we studied mice during the first week of HFD exposure, determining the onset of proliferation in the context of diet-related physiological changes. Within the first week of HFD, mice consumed more kilocalories, gained weight and fat mass, and developed hyperglycemia, hyperinsulinemia, and glucose intolerance due to impaired insulin secretion. The β-cell proliferative response also began within the first week of HFD feeding. Intriguingly, β-cell proliferation increased before insulin resistance was detected. Cyclin D2 protein expression was increased in islets by day 7, suggesting it may be an early effector driving compensatory β-cell proliferation in mice. This study defines the time frame and physiology to identify novel upstream regulatory signals driving mouse β-cell mass expansion, in order to explore their efficacy, or reasons for inefficacy, in initiating human β-cell proliferation.
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Affiliation(s)
- Rachel E Stamateris
- Division of Diabetes, University of Massachusetts Medical School, Worcester, MA, USA
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20
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Sharma RB, Wang Q, Khillan JS. Amplification of tumor inducing putative cancer stem cells (CSCs) by vitamin A/retinol from mammary tumors. Biochem Biophys Res Commun 2013; 436:625-31. [PMID: 23764401 DOI: 10.1016/j.bbrc.2013.05.141] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 05/31/2013] [Indexed: 01/16/2023]
Abstract
Solid tumors contain a rare population of cancer stem cells (CSCs) that are responsible for relapse and metastasis. The existence of CSC however, remains highly controversial issue. Here we present the evidence for putative CSCs from mammary tumors amplified by vitamin A/retinol signaling. The cells exhibit mammary stem cell specific CD29(hi)/CD49f(hi)/CD24(hi) markers, resistance to radiation and chemo therapeutic agents and form highly metastatic tumors in NOD/SCID mice. The cells exhibit indefinite self renewal as cell lines. Furthermore, the cells exhibit impaired retinol metabolism and do not express enzymes that metabolize retinol into retinoic acid. Vitamin A/retinol also amplified putative CSCs from breast cancer cell lines that form highly aggressive tumors in NOD SCID mice. The studies suggest that high purity putative CSCs can be isolated from solid tumors to establish patient specific cell lines for personalized therapeutics for pre-clinical translational applications. Characterization of CSCs will allow understanding of basic cellular and molecular pathways that are deregulated, mechanisms of tumor metastasis and evasion of therapies that has direct clinical relevance.
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Affiliation(s)
- Rohit B Sharma
- Department of Microbiology and Molecular Genetics, University of Pittsburgh, PA 15261, USA
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21
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Abstract
Autoimmune thyroiditis in humans has been linked to excess iodine intake. A causative relationship between dietary iodine and thyroiditis has been clearly established in animal models of thyroiditis, including the NOD.H2(h4) mouse strain, which develops enhanced thyroiditis spontaneously after supplementation of drinking water with sodium iodide. To assess the mechanisms by which iodine may contribute to disease pathogenesis, we have purified hypoiodinated thyroglobulin (Lo-I Tg) from the thyroids of mice fed methimazole and potassium perchlorate. This preparation contained only a trace of iodine and was poorly reactive to monoclonal antibody 42C3, which has been shown previously to distinguish hypoiodinated from normal Tg. A cloned T cell line 2D11 from a diseased NOD.H2(h4) mouse proliferated in response to normal Tg, but not to Lo-I Tg. Serum antibodies from NOD.H2(h4) mice with thyroiditis were poorly reactive to Lo-I Tg. To determine that these changes were due specifically to iodine content, Lo-I Tg was reiodinated in vitro. Reiodination of Lo-I Tg partially re-established the reactivity of NOD.H2(h4) serum antibodies. The data demonstrate that the reactivity of thyroglobulin-specific antibodies and certain T cells are dependent on the iodine content of thyroglobulin. These findings suggest that iodine contributes to autoimmune thyroiditis in the NOD.H2(h4) mouse by directly enhancing the antigenicity of thyroglobulin.
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Affiliation(s)
- J G Barin
- Johns Hopkins University School of Medicine, Department of Pathology, Baltimore, MD 21205, USA
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22
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Gupta M, Mangoli S, Sharma P, Sharma RB, Jora R, Meena K. Role of intra-muscular magnesium therapy in management of persistent apnea and prevention of adverse life threatening events. Indian Pediatr 2001; 38:646-9. [PMID: 11418730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Affiliation(s)
- M Gupta
- Department of Pediatrics, Regional Institute of Maternal and Child Health, Dr. S.N. Medical College, Jodhpur, India
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23
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24
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Gupta M, Jain K, Sharma RB, Managoli S, Khandelwal R. Correlation of serum and CSF magnesium levels of normal newborns with maternal serum magnesium. Indian J Pediatr 2000; 67:242-3. [PMID: 10838731 DOI: 10.1007/bf02723674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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25
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Gupta BD, Bhaskar S, Karkra A, Sharma RB, Arora AK. Investigation of children with chronic diarrhoea. Trop Gastroenterol 1999; 20:85-6. [PMID: 10484897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
OBJECTIVE To study the lower G.I. endoscopic and histopathological findings in children with chronic diarrhoea. DESIGN Prospective analysis. SETTING Hospital based. SUBJECT 83 children with age up to 14 years admitted in Umaid Hospital, Jodhpur including 33 subjects with chronic diarrhoea and 50 normal children in control group. METHODS All 83 children including study (33) and control group (50) underwent lower G.I. Endoscopy using FUJINON-SIG-ET sigmoidoscope in older children and PENTAX FG-23H gastroscope in younger children after proper preparation. Rectal biopsies were taken in all the subjects except one and was sent for histopathological examination. RESULTS Majority (90.8%) were in 0-5 year age group with median age of 3.8 years. We could finally reach to definitive diagnosis in 13% patients with chronic diarrhoea. Over all, colitis was the most common cause. CONCLUSION Both, endoscopy and biopsy are needed to reach final diagnosis.
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Affiliation(s)
- B D Gupta
- Department of Paediatrics, Regional Institute of Maternal and Child Health, Umaid Hospital, Dr. S.N Medical College, Jodhpur, India
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Abstract
Although spermatozoa express antigens, they normally do not produce an immunological response because of the blood-testis barrier and the predominance of CD8(+) T-lymphocytes in the rete testis. Unilateral blunt testicular trauma (UBTT) has been reported to decrease fertility. The present study was designed to evaluate the sub-populations of T-lymphocytes in mice with testicular trauma. Twenty male mice aged 20 days were randomized into control and test groups. At about 70 days of age the contralateral testis was harvested, cell suspensions were prepared, and immunofluorescence staining was performed for detection of CD4(+ )and CD8(+) T-lymphocytes by flow-cytometry. The ratio of CD8(+) and CD4(+) lymphocytes was significantly higher (P < 0.001) in the control mice compared to the UBTT group (1.3 +/- 0.3 vs 0.5 +/- 0.01). The results suggest that UBTT alters the CD8(+)/CD4(+) ratio in the contralateral testis, which may have an important bearing on the pathogenesis of infertility in cases of testicular injury.
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Affiliation(s)
- R B Sharma
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
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Gupta M, Sharma RB, Parakh M. Pseudo-homozygous type IIa hypercholesterolemia. Indian Pediatr 1997; 34:734-7. [PMID: 9492405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- M Gupta
- Department of Pediatrics, Medical College, Jodhpur
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Gupta BD, Parakh M, Sharma RB. Hemoperitoneum--a rare manifestation of early hemorrhagic disease of newborn. Indian Pediatr 1996; 33:874-5. [PMID: 9057393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Sharma RB, Goyal M, Singh J. Comparison of scholastic performances of left handed and right handed students. Indian Pediatr 1993; 30:1189-92. [PMID: 8077009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
An attempt was made to compare the scholastic performance among left and right handed students. Both academic and extra curricular areas were studied among 3608 students from 6th to 12th class, from 10 schools in a rural subdivision of north east Rajasthan. General incidence of left handedness was 8.6% among students, higher in females (12.4%) as compared to males (8.1%). Right handed students performed better in aggregate as well as in individual academic areas (p < 0.05). Left handed students were extreme performers as far as sports and games area was concerned, while right handed students tended to be average performers. Overall handedness affected both the academic and extra-curricular activities except behavior and discipline area (p > 0.05).
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Affiliation(s)
- R B Sharma
- Community Health Centre, Patan, District Sikar, Rajasthan
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Abstract
Levuglandin E2 (LGE2), a gamma-ketoaldehyde produced by rearrangement of the prostaglandin endoperoxide PGH2 under the aqueous conditions of its biosynthesis, binds covalently with ram seminal vesicle microsomes. Totally synthetic 5,6-ditritio-LGE2 was prepared and used to determine that rapid covalent binding of LGE2 (initially 800 microM) occurs with 6.4 microM bovine serum albumin (greater than 10 equiv within 1 min) which approaches saturation (approximately 16 equiv) after 40 min at 37 degrees C.
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Affiliation(s)
- R G Salomon
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106-2699
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Abstract
Oral intubation of culture filtrates of Aspergillus flavus and A. terreus produced hepatocellular damage in albino rats in the form of perilobular hypertrophy of the parenchymal cells and vacuolar degeneration of cytoplasm. Focal necrosis and early periportal fibrosis were also evident.
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Abstract
The oral intubation of culture filtrates produced nephrotoxic damages in the form of marked capillaritis, shrinkage and early fibrosis of glomeruli. Hypertrophy and degeneration of tubular epithelium were also evident. The spleen of treated animals revealed subacute splenitis in the form of congestion of the splenic sinuses.
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