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Tong X, Yagan M, Hu R, Nevills S, Doss TD, Stein RW, Balamurugan AN, Gu G. Metabolic Stress Levels Influence the Ability of Myelin Transcription Factors to Regulate β-Cell Identity and Survival. Diabetes 2024; 73:1662-1672. [PMID: 39058602 PMCID: PMC11417441 DOI: 10.2337/db23-0528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 07/14/2024] [Indexed: 07/28/2024]
Abstract
A hallmark of type 2 diabetes (T2D) is endocrine islet β-cell failure, which can occur via cell dysfunction, loss of identity, and/or death. How each is induced remains largely unknown. We used mouse β-cells deficient for myelin transcription factors (Myt TFs; including Myt1, -2, and -3) to address this question. We previously reported that inactivating all three Myt genes in pancreatic progenitor cells (MytPancΔ) caused β-cell failure and late-onset diabetes in mice. Their lower expression in human β-cells is correlated with β-cell dysfunction, and single nucleotide polymorphisms in MYT2 and MYT3 are associated with a higher risk of T2D. We now show that these Myt TF-deficient postnatal β-cells also dedifferentiate by reactivating several progenitor markers. Intriguingly, mosaic Myt TF inactivation in only a portion of islet β-cells did not result in overt diabetes, but this created a condition where Myt TF-deficient β-cells remained alive while activating several markers of Ppy-expressing islet cells. By transplanting MytPancΔ islets into the anterior eye chambers of immune-compromised mice, we directly show that glycemic and obesity-related conditions influence cell fate, with euglycemia inducing several Ppy+ cell markers and hyperglycemia and insulin resistance inducing additional cell death. These findings suggest that the observed β-cell defects in T2D depend not only on their inherent genetic/epigenetic defects but also on the metabolic load. ARTICLE HIGHLIGHTS
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Affiliation(s)
- Xin Tong
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Mahircan Yagan
- Program in Developmental Biology, Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN
- Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN
| | - Ruiying Hu
- Program in Developmental Biology, Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN
- Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN
| | - Simone Nevills
- Program in Developmental Biology, Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN
- Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN
| | - Teri D. Doss
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Roland W. Stein
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Appakalai N. Balamurugan
- Center for Clinical and Translational Research, Abigail Wexner Research Institute, Nationwide Children’s Hospital, Columbus, OH
- Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH
| | - Guoqiang Gu
- Program in Developmental Biology, Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN
- Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN
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Yagan M, Najam S, Hu R, Wang Y, Dadi P, Xu Y, Simmons AJ, Stein R, Adams CM, Jacobson DA, Lau K, Liu Q, Gu G. Atf4 protects islet β-cell identity and function under acute glucose-induced stress but promotes β-cell failure in the presence of free fatty acid. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.28.601249. [PMID: 39005465 PMCID: PMC11244863 DOI: 10.1101/2024.06.28.601249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
Glucolipotoxicity, caused by combined hyperglycemia and hyperlipidemia, results in β-cell failure and type 2 diabetes (T2D) via cellular stress-related mechanisms. Activating transcription factor 4 (Atf4) is an essential effector of stress response. We show here that Atf4 expression in β-cells is dispensable for glucose homeostasis in young mice, but it is required for β-cell function during aging and under obesity-related metabolic stress. Henceforth, aged Atf4- deficient β-cells display compromised secretory function under acute hyperglycemia. In contrast, they are resistant to acute free fatty acid-induced loss-of identity and dysfunction. At molecular level, Atf4 -deficient β-cells down-regulate genes involved in protein translation, reducing β-cell identity gene products under high glucose. They also upregulate several genes involved in lipid metabolism or signaling, likely contributing to their resistance to free fatty acid-induced dysfunction. These results suggest that Atf4 activation is required for β-cell identity and function under high glucose, but this paradoxically induces β-cell failure in the presence of high levels of free fatty acids. Different branches of Atf4 activity could be manipulated for protecting β-cells from metabolic stress-induced failure. Highlights Atf4 is dispensable in β-cells in young miceAtf4 protects β-cells under high glucoseAtf4 exacerbate fatty acid-induced β-cell defectsAtf4 activates translation but depresses lipid-metabolism.
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Zhang N, Nao J, Zhang S, Dong X. Novel insights into the activating transcription factor 4 in Alzheimer's disease and associated aging-related diseases: Mechanisms and therapeutic implications. Front Neuroendocrinol 2024; 74:101144. [PMID: 38797197 DOI: 10.1016/j.yfrne.2024.101144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 05/16/2024] [Accepted: 05/22/2024] [Indexed: 05/29/2024]
Abstract
Ageing is inherent to all human beings, most mechanistic explanations of ageing results from the combined effects of various physiological and pathological processes. Additionally, aging pivotally contributes to several chronic diseases. Activating transcription factor 4 (ATF4), a member of the ATF/cAMP response element-binding protein family, has recently emerged as a pivotal player owing to its indispensable role in the pathophysiological processes of Alzheimer's disease and aging-related diseases. Moreover, ATF4 is integral to numerous biological processes. Therefore, this article aims to comprehensively review relevant research on the role of ATF4 in the onset and progression of aging-related diseases, elucidating its potential mechanisms and therapeutic approaches. Our objective is to furnish scientific evidence for the early identification of risk factors in aging-related diseases and pave the way for new research directions for their treatment. By elucidating the signaling pathway network of ATF4 in aging-related diseases, we aspire to gain a profound understanding of the molecular and cellular mechanisms, offering novel strategies for addressing aging and developing related therapeutics.
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Affiliation(s)
- Nan Zhang
- Department of Neurology, the Seventh Clinical College of China Medical University, No. 24 Central Street, Xinfu District, Fushun 113000, Liaoning, China.
| | - Jianfei Nao
- Department of Neurology, Shengjing Hospital of China Medical University, No. 36 Sanhao Street, Heping District, Shenyang 110000, Liaoning, China.
| | - Shun Zhang
- Department of Neurology, Shengjing Hospital of China Medical University, No. 36 Sanhao Street, Heping District, Shenyang 110000, Liaoning, China.
| | - Xiaoyu Dong
- Department of Neurology, Shengjing Hospital of China Medical University, No. 36 Sanhao Street, Heping District, Shenyang 110000, Liaoning, China.
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Gu G, Brown M, Agan V, Nevills S, Hu R, Simmons A, Xu Y, Yang Y, Yagan M, Najam S, Dadi P, Sampson L, Magnuson M, Jacobson D, Lau K, Hodges E. Endocrine islet β-cell subtypes with differential function are derived from biochemically distinct embryonic endocrine islet progenitors that are regulated by maternal nutrients. RESEARCH SQUARE 2024:rs.3.rs-3946483. [PMID: 38496675 PMCID: PMC10942487 DOI: 10.21203/rs.3.rs-3946483/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Endocrine islet b cells comprise heterogenous cell subsets. Yet when/how these subsets are produced and how stable they are remain unknown. Addressing these questions is important for preventing/curing diabetes, because lower numbers of b cells with better secretory function is a high risk of this disease. Using combinatorial cell lineage tracing, scRNA-seq, and DNA methylation analysis, we show here that embryonic islet progenitors with distinct gene expression and DNA methylation produce b-cell subtypes of different function and viability in adult mice. The subtype with better function is enriched for genes involved in vesicular production/trafficking, stress response, and Ca2+-secretion coupling, which further correspond to differential DNA methylation in putative enhancers of these genes. Maternal overnutrition, a major diabetes risk factor, reduces the proportion of endocrine progenitors of the b-cell subtype with better-function via deregulating DNA methyl transferase 3a. Intriguingly, the gene signature that defines mouse b-cell subtypes can reliably divide human cells into two sub-populations while the proportion of b cells with better-function is reduced in diabetic donors. The implication of these results is that modulating DNA methylation in islet progenitors using maternal food supplements can be explored to improve b-cell function in the prevention and therapy of diabetes.
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Affiliation(s)
| | | | | | | | | | | | | | - Yilin Yang
- Vanderbilty University School of Medicine
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Lee JH, Ryu H, Lee H, Yu HR, Gao Y, Lee KM, Kim YJ, Lee J. Endoplasmic reticulum stress in pancreatic β cells induces incretin desensitization and β-cell dysfunction via ATF4-mediated PDE4D expression. Am J Physiol Endocrinol Metab 2023; 325:E448-E465. [PMID: 37729023 DOI: 10.1152/ajpendo.00156.2023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 08/18/2023] [Accepted: 09/05/2023] [Indexed: 09/22/2023]
Abstract
Pancreatic β-cell dysfunction and eventual loss are key steps in the progression of type 2 diabetes (T2D). Endoplasmic reticulum (ER) stress responses, especially those mediated by the protein kinase RNA-like ER kinase and activating transcription factor 4 (PERK-ATF4) pathway, have been implicated in promoting these β-cell pathologies. However, the exact molecular events surrounding the role of the PERK-ATF4 pathway in β-cell dysfunction remain unknown. Here, we report our discovery that ATF4 promotes the expression of PDE4D, which disrupts β-cell function via a downregulation of cAMP signaling. We found that β-cell-specific transgenic expression of ATF4 led to early β-cell dysfunction and loss, a phenotype that resembles accelerated T2D. Expression of ATF4, rather than C/EBP homologous protein (CHOP), promoted PDE4D expression, reduced cAMP signaling, and attenuated responses to incretins and elevated glucose. Furthermore, we found that β-cells of leptin receptor-deficient diabetic (db/db) mice had elevated nuclear localization of ATF4 and PDE4D expression, accompanied by impaired β-cell function. Accordingly, pharmacological inhibition of the ATF4 pathway attenuated PDE4D expression in the islets and promoted incretin-simulated glucose tolerance and insulin secretion in db/db mice. Finally, we found that inhibiting PDE4 activity with selective pharmacological inhibitors improved β-cell function in both db/db mice and β-cell-specific ATF4 transgenic mice. In summary, our results indicate that ER stress causes β-cell failure via ATF4-mediated PDE4D production, suggesting the ATF4-PDE4D pathway could be a therapeutic target for protecting β-cell function during the progression of T2D.NEW & NOTEWORTHY Endoplasmic reticulum stress has been implied to cause multiple β-cell pathologies during the progression of type 2 diabetes (T2D). However, the precise molecular events underlying this remain unknown. Here, we discovered that elevated ATF4 activity, which was seen in T2D β cells, attenuated β-cell proliferation and impaired insulin secretion via PDE4D-mediated downregulation of cAMP signaling. Additionally, we demonstrated that pharmacological inhibition of the ATF4 pathway or PDE4D activity alleviated β-cell dysfunction, suggesting its therapeutic usefulness against T2D.
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Affiliation(s)
- Ji-Hye Lee
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology, Daegu, Republic of Korea
- New Biology Research Center, Daegu Gyeongbuk Institute of Science and Technology, Daegu, Republic of Korea
| | - Hanguk Ryu
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology, Daegu, Republic of Korea
| | - Hyejin Lee
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology, Daegu, Republic of Korea
| | - Hye Ram Yu
- Well Aging Research Center, Daegu Gyeongbuk Institute of Science and Technology, Daegu, Republic of Korea
| | - Yurong Gao
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology, Daegu, Republic of Korea
| | - Kyeong-Min Lee
- Division of Biotechnology, Daegu Gyeongbuk Institute of Science and Technology, Daegu, Republic of Korea
| | - Young-Joon Kim
- Department of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
| | - Jaemin Lee
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology, Daegu, Republic of Korea
- New Biology Research Center, Daegu Gyeongbuk Institute of Science and Technology, Daegu, Republic of Korea
- Well Aging Research Center, Daegu Gyeongbuk Institute of Science and Technology, Daegu, Republic of Korea
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Nunnelly LF, Campbell M, Lee DI, Dummer P, Gu G, Menon V, Au E. St18 specifies globus pallidus projection neuron identity in MGE lineage. Nat Commun 2022; 13:7735. [PMID: 36517477 PMCID: PMC9751150 DOI: 10.1038/s41467-022-35518-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 12/08/2022] [Indexed: 12/15/2022] Open
Abstract
The medial ganglionic eminence (MGE) produces both locally-projecting interneurons, which migrate long distances to structures such as the cortex as well as projection neurons that occupy subcortical nuclei. Little is known about what regulates the migratory behavior and axonal projections of these two broad classes of neurons. We find that St18 regulates the migration and morphology of MGE neurons in vitro. Further, genetic loss-of-function of St18 in mice reveals a reduction in projection neurons of the globus pallidus pars externa. St18 functions by influencing cell fate in MGE lineages as we observe a large expansion of nascent cortical interneurons at the expense of putative GPe neurons in St18 null embryos. Downstream of St18, we identified Cbx7, a component of Polycomb repressor complex 1, and find that it is essential for projection neuron-like migration but not morphology. Thus, we identify St18 as a key regulator of projection neuron vs. interneuron identity.
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Affiliation(s)
- Luke F Nunnelly
- Department of Pathology & Cell Biology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Melissa Campbell
- Department of Pathology & Cell Biology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Dylan I Lee
- Department of Neurology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Patrick Dummer
- Department of Pathology & Cell Biology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Guoqiang Gu
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Vilas Menon
- Department of Neurology, Columbia University Irving Medical Center, New York, NY, 10032, USA
| | - Edmund Au
- Department of Pathology & Cell Biology, Columbia University Irving Medical Center, New York, NY, 10032, USA.
- Department of Rehabilitation and Regenerative Medicine, Columbia University Irving Medical Center, New York, NY, 10032, USA.
- Columbia Translational Neuroscience Initiative Scholar, Columbia University Irving Medical Center, New York, NY, 10032, USA.
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La(OH)3 Multi-Walled Carbon Nanotube/Carbon Paste-Based Sensing Approach for the Detection of Uric Acid—A Product of Environmentally Stressed Cells. BIOSENSORS 2022; 12:bios12090705. [PMID: 36140095 PMCID: PMC9496040 DOI: 10.3390/bios12090705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 08/21/2022] [Accepted: 08/24/2022] [Indexed: 11/24/2022]
Abstract
This paper aims to develop an amperometric, non-enzymatic sensor for detecting and quantifying UA as an alert signal induced by allergens with protease activity in human cell lines (HEK293 and HeLa). Uric acid (UA) has been classified as a damage-associated molecular pattern (DAMP) molecule that serves a physiological purpose inside the cell, while outside the cell it can be an indicator of cell damage. Cell damage or stress can be caused by different health problems or by environmental irritants, such as allergens. We can act and prevent the events that generate stress by determining the extent to which cells are under stress. Amperometric calibration measurements were performed with a carbon paste electrode modified with La(OH)3@MWCNT, at the potential of 0.3 V. The calibration curve was constructed in a linear operating range from 0.67 μM to 121 μM UA. The proposed sensor displayed good reproducibility with an RSD of 3.65% calculated for five subsequent measurements, and a low detection limit of 64.28 nM, determined using the 3 S/m method. Interference studies and the real sample analysis of allergen-treated cell lines proved that the proposed sensing platform possesses excellent sensitivity, reproducibility, and stability. Therefore, it can potentially be used to evaluate stress factors in medical research and clinical practice.
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Sobajima M, Miyake M, Hamada Y, Tsugawa K, Oyadomari M, Inoue R, Shirakawa J, Arima H, Oyadomari S. The multifaceted role of ATF4 in regulating glucose-stimulated insulin secretion. Biochem Biophys Res Commun 2022; 611:165-171. [PMID: 35489203 DOI: 10.1016/j.bbrc.2022.04.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 04/08/2022] [Indexed: 11/02/2022]
Abstract
Stress-inducible transcription factor ATF4 is essential for survival and identity of β-cell during stress conditions. However, the physiological role of ATF4 in β-cell function is not yet completely understood. To understand the role of ATF4 in glucose-stimulated insulin secretion (GSIS), β-cell-specific Atf4 knockout (βAtf4KO) mice were phenotypically characterized. Insulin secretion and mechanistic analyses were performed using islets from control Atf4f/f and βAtf4KO mice to assess key regulators for triggering and amplifying signals for GSIS. βAtf4KO mice displayed glucose intolerance due to reduced insulin secretion. Moreover, βAtf4KO islets exhibited a decrease in both the insulin content and first-phase insulin secretion. The analysis of βAtf4KO islets showed that ATF4 is required for insulin production and glucose-stimulated ATP and cAMP production. The results demonstrate that ATF4 contributes to the multifaceted regulatory process in GSIS even under stress-free conditions.
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Affiliation(s)
- Mitsuaki Sobajima
- Division of Molecular Biology, Institute of Advanced Medical Sciences, Tokushima University, 3-18-15 Kuramoto, Tokushima, 770-8503, Japan; Department of Molecular Physiology, Diabetes Therapeutics and Research Center, Tokushima University, 3-18-15 Kuramoto, Tokushima, 770-8503, Japan; Fujii Memorial Institute of Medical Sciences, Institute of Advanced Medical Sciences, Tokushima University, 3-18-15 Kuramoto, Tokushima, 770-8503, Japan; Laboratory of Diabetes and Metabolic Disorders, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi, 371-8512, Japan
| | - Masato Miyake
- Division of Molecular Biology, Institute of Advanced Medical Sciences, Tokushima University, 3-18-15 Kuramoto, Tokushima, 770-8503, Japan; Department of Molecular Physiology, Diabetes Therapeutics and Research Center, Tokushima University, 3-18-15 Kuramoto, Tokushima, 770-8503, Japan; Fujii Memorial Institute of Medical Sciences, Institute of Advanced Medical Sciences, Tokushima University, 3-18-15 Kuramoto, Tokushima, 770-8503, Japan
| | - Yoshimasa Hamada
- Division of Molecular Biology, Institute of Advanced Medical Sciences, Tokushima University, 3-18-15 Kuramoto, Tokushima, 770-8503, Japan; Department of Molecular Physiology, Diabetes Therapeutics and Research Center, Tokushima University, 3-18-15 Kuramoto, Tokushima, 770-8503, Japan; Fujii Memorial Institute of Medical Sciences, Institute of Advanced Medical Sciences, Tokushima University, 3-18-15 Kuramoto, Tokushima, 770-8503, Japan
| | - Kazue Tsugawa
- Division of Molecular Biology, Institute of Advanced Medical Sciences, Tokushima University, 3-18-15 Kuramoto, Tokushima, 770-8503, Japan
| | - Miho Oyadomari
- Division of Molecular Biology, Institute of Advanced Medical Sciences, Tokushima University, 3-18-15 Kuramoto, Tokushima, 770-8503, Japan
| | - Ryota Inoue
- Laboratory of Diabetes and Metabolic Disorders, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi, 371-8512, Japan
| | - Jun Shirakawa
- Laboratory of Diabetes and Metabolic Disorders, Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi, 371-8512, Japan
| | - Hiroshi Arima
- Department of Endocrinology and Diabetes, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8560, Japan
| | - Seiichi Oyadomari
- Division of Molecular Biology, Institute of Advanced Medical Sciences, Tokushima University, 3-18-15 Kuramoto, Tokushima, 770-8503, Japan; Department of Molecular Physiology, Diabetes Therapeutics and Research Center, Tokushima University, 3-18-15 Kuramoto, Tokushima, 770-8503, Japan; Fujii Memorial Institute of Medical Sciences, Institute of Advanced Medical Sciences, Tokushima University, 3-18-15 Kuramoto, Tokushima, 770-8503, Japan.
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Darden CM, Vasu S, Mattke J, Liu Y, Rhodes CJ, Naziruddin B, Lawrence MC. Calcineurin/NFATc2 and PI3K/AKT signaling maintains β-cell identity and function during metabolic and inflammatory stress. iScience 2022; 25:104125. [PMID: 35402865 PMCID: PMC8983383 DOI: 10.1016/j.isci.2022.104125] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 12/02/2021] [Accepted: 03/16/2022] [Indexed: 11/19/2022] Open
Abstract
Pancreatic islets respond to metabolic and inflammatory stress by producing hormones and other factors that induce adaptive cellular and systemic responses. Here we show that intracellular Ca2+ ([Ca2+]i) and ROS signals generated by high glucose and cytokine-induced ER stress activate calcineurin (CN)/NFATc2 and PI3K/AKT to maintain β-cell identity and function. This was attributed in part by direct induction of the endocrine differentiation gene RFX6 and suppression of several β-cell "disallowed" genes, including MCT1. CN/NFATc2 targeted p300 and HDAC1 to RFX6 and MCT1 promoters to induce and suppress gene transcription, respectively. In contrast, prolonged exposure to stress, hyperstimulated [Ca2+]i, or perturbation of CN/NFATc2 resulted in downregulation of RFX6 and induction of MCT1. These findings reveal that CN/NFATc2 and PI3K/AKT maintain β-cell function during acute stress, but β-cells dedifferentiate to a dysfunctional state upon loss or exhaustion of Ca2+/CN/NFATc2 signaling. They further demonstrate the utility of targeting CN/NFATc2 to restore β-cell function.
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Affiliation(s)
- Carly M. Darden
- Islet Cell Laboratory, Baylor Scott & White Research Institute, Dallas, TX 75204, USA
- Institute of Biomedical Studies, Baylor University, Waco, TX 76706, USA
| | - Srividya Vasu
- Islet Cell Laboratory, Baylor Scott & White Research Institute, Dallas, TX 75204, USA
| | - Jordan Mattke
- Islet Cell Laboratory, Baylor Scott & White Research Institute, Dallas, TX 75204, USA
- Institute of Biomedical Studies, Baylor University, Waco, TX 76706, USA
| | - Yang Liu
- Annette C. and Harold C. Simmons Transplant Institute, Baylor University Medical Center, Dallas, TX 75246, USA
| | - Christopher J. Rhodes
- Kovler Diabetes Center, Department of Medicine, Section of Endocrinology, Diabetes & Metabolism, University of Chicago, Chicago, IL 60637, USA
- Research and Early Development, Cardiovascular, Renal and Metabolic Diseases, BioPharmaceuticals R&D, AstraZeneca Ltd, Gaithersburg, MD 20878, USA
| | - Bashoo Naziruddin
- Annette C. and Harold C. Simmons Transplant Institute, Baylor University Medical Center, Dallas, TX 75246, USA
| | - Michael C. Lawrence
- Islet Cell Laboratory, Baylor Scott & White Research Institute, Dallas, TX 75204, USA
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ATF4-mediated transcriptional regulation protects against β-cell loss during endoplasmic reticulum stress in a mouse model. Mol Metab 2021; 54:101338. [PMID: 34547510 PMCID: PMC8487982 DOI: 10.1016/j.molmet.2021.101338] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 09/02/2021] [Accepted: 09/02/2021] [Indexed: 01/08/2023] Open
Abstract
OBJECTIVE Activating transcription factor 4 (ATF4) is a transcriptional regulator of the unfolded protein response and integrated stress response (ISR) that promote the restoration of normal endoplasmic reticulum (ER) function. Previous reports demonstrated that dysregulation of the ISR led to development of severe diabetes. However, the contribution of ATF4 to pancreatic β-cells remains poorly understood. In this study, we aimed to analyze the effect of ISR enhancer Sephin1 and ATF4-deficient β-cells to clarify the role of ATF4 in β-cells under ER stress conditions. METHODS To examine the role of ATF4 in vivo, ISR enhancer Sephin1 (5 mg/kg body weight, p.o.) was administered daily for 21 days to Akita mice. We also established β-cell-specific Atf4 knockout (βAtf4-KO) mice that were further crossed with Akita mice. These mice were analyzed for characteristics of diabetes, β-cell function, and morphology of the islets. To identify the downstream factors of ATF4 in β-cells, the islets of βAtf4-KO mice were subjected to cDNA microarray analyses. To examine the transcriptional regulation by ATF4, we also performed in situ PCR analysis of pancreatic sections from mice and ChIP-qPCR analysis of CT215 β-cells. RESULTS Administration of the ISR enhancer Sephin1 improved glucose metabolism in Akita mice. Sephin1 also increased the insulin-immunopositive area and ATF4 expression in the pancreatic islets. Akita/βAtf4-KO mice exhibited dramatically exacerbated diabetes, shown by hyperglycemia at an early age, as well as a remarkably short lifespan owing to diabetic ketoacidosis. Moreover, the islets of Akita/βAtf4-KO mice presented increased numbers of cells stained for glucagon, somatostatin, and pancreatic polypeptide and increased expression of aldehyde dehydrogenase 1 family member 3, a marker of dedifferentiation. Using microarray analysis, we identified atonal BHLH transcription factor 8 (ATOH8) as a downstream factor of ATF4. Deletion of ATF4 in β-cells showed reduced Atoh8 expression and increased expression of undifferentiated markers, Nanog and Pou5f1. Atoh8 expression was also abolished in the islets of Akita/βAtf4-KO mice. CONCLUSIONS We conclude that transcriptional regulation by ATF4 maintains β-cell identity via ISR modulation. This mechanism provides a promising target for the treatment of diabetes.
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Hu R, Zhu X, Yuan M, Ho KH, Kaverina I, Gu G. Microtubules and Gαo-signaling modulate the preferential secretion of young insulin secretory granules in islet β cells via independent pathways. PLoS One 2021; 16:e0241939. [PMID: 34292976 PMCID: PMC8297875 DOI: 10.1371/journal.pone.0241939] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 06/15/2021] [Indexed: 12/24/2022] Open
Abstract
For sustainable function, each pancreatic islet β cell maintains thousands of insulin secretory granules (SGs) at all times. Glucose stimulation induces the secretion of a small portion of these SGs and simultaneously boosts SG biosynthesis to sustain this stock. The failure of these processes, often induced by sustained high-insulin output, results in type 2 diabetes. Intriguingly, young insulin SGs are more likely secreted during glucose-stimulated insulin secretion (GSIS) for unknown reasons, while older SGs tend to lose releasability and be degraded. Here, we examine the roles of microtubule (MT) and Gαo-signaling in regulating the preferential secretion of young versus old SGs. We show that both MT-destabilization and Gαo inactivation results in more SGs localization near plasma membrane (PM) despite higher levels of GSIS and reduced SG biosynthesis. Intriguingly, MT-destabilization or Gαo-inactivation results in higher secretion probabilities of older SGs, while combining both having additive effects on boosting GSIS. Lastly, Gαo inactivation does not detectably destabilize the β-cell MT network. These findings suggest that Gαo and MT can modulate the preferential release of younger insulin SGs via largely parallel pathways.
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Affiliation(s)
- Ruiying Hu
- Department of Cell and Developmental Biology, The Program of Developmental Biology and the Center for Stem Cell Biology, Vanderbilt University, Nashville, TN, United States of America
| | - Xiaodong Zhu
- Department of Cell and Developmental Biology, The Program of Developmental Biology and the Center for Stem Cell Biology, Vanderbilt University, Nashville, TN, United States of America
| | - Mingyang Yuan
- Department of Cell and Developmental Biology, The Program of Developmental Biology and the Center for Stem Cell Biology, Vanderbilt University, Nashville, TN, United States of America
| | - Kung-Hsien Ho
- Department of Cell and Developmental Biology, The Program of Developmental Biology and the Center for Stem Cell Biology, Vanderbilt University, Nashville, TN, United States of America
| | - Irina Kaverina
- Department of Cell and Developmental Biology, The Program of Developmental Biology and the Center for Stem Cell Biology, Vanderbilt University, Nashville, TN, United States of America
- * E-mail: (GG); (IK)
| | - Guoqiang Gu
- Department of Cell and Developmental Biology, The Program of Developmental Biology and the Center for Stem Cell Biology, Vanderbilt University, Nashville, TN, United States of America
- * E-mail: (GG); (IK)
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12
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Ni Q, Song J, Wang Y, Sun J, Xie J, Zhang J, Ning G, Wang W, Wang Q. Proper mTORC1 Activity Is Required for Glucose Sensing and Early Adaptation in Human Pancreatic β Cells. J Clin Endocrinol Metab 2021; 106:e562-e572. [PMID: 33120423 DOI: 10.1210/clinem/dgaa786] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Indexed: 12/25/2022]
Abstract
CONTEXT The mechanistic target of rapamycin complex I (mTORC1) is crucial for β-cell identity and function in rodents. However, its possible relevance to the physiopathology of diabetes in humans remains unclear. OBJECTIVE This work aimed to understand the participation of mTORC1 in human β cells in prediabetes and diabetes. DESIGN We evaluated the PS6 immunofluorescence intensity in islets of pancreatic sections from 12 nondiabetic (ND), 11 impaired fasting glucose (IFG), and 11 glycemic-controlled type 2 diabetic (T2D) individuals. We also assessed the dynamic change of mTORC1 activity in β cells of db/db mice with new-onset diabetes. RESULTS There exists intercellular heterogeneity of mTORC1 activities in human islets. Islet mTORC1 activity was independently and positively correlated with FBG in ND, but not in IFG and T2D. Moreover, we did not detect significant change in mTORC1 activities between T2D and ND. Of note, the islet mTORC1 activities were significantly higher in IFG than in ND. We further stratified IFG individuals according to their islet PS6 levels and found that IFG-PS6high exhibited remarkably higher urocortin3 and glucose transporter 2 expression in their β cells compared to IFG-PS6low. Consistently, we also detected a significant increase in mTORC1 activities in prediabetic db/db mice compared to nondiabetic littermates. Interestingly, mTORC1 activities determined β-cell adaptation or failure in db/db mice: A strong negative correlation was found between islet mTORC1 activities and fasting glucose levels in db/db mice during their diabetes progression. CONCLUSIONS Our finding highlights a dynamic islet mTORC1 response in β-cell adaption/failure in human T2D.
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Affiliation(s)
- Qicheng Ni
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jiaxi Song
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yichen Wang
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jiajun Sun
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jing Xie
- Department of Pathology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jun Zhang
- Department of General Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Guang Ning
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Weiqing Wang
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qidi Wang
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Sino-French Research Center for Life Sciences and Genomics, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
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13
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Milan M, Balestrieri C, Alfarano G, Polletti S, Prosperini E, Nicoli P, Spaggiari P, Zerbi A, Cirulli V, Diaferia GR, Natoli G. Pancreatic Cancer Cells Require the Transcription Factor MYRF to Maintain ER Homeostasis. Dev Cell 2020; 55:398-412.e7. [PMID: 32997974 DOI: 10.1016/j.devcel.2020.09.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 07/31/2020] [Accepted: 09/04/2020] [Indexed: 01/01/2023]
Abstract
Many tumors of endodermal origin are composed of highly secretory cancer cells that must adapt endoplasmic reticulum (ER) activity to enable proper folding of secreted proteins and prevent ER stress. We found that pancreatic ductal adenocarcinomas (PDACs) overexpress the myelin regulatory factor (MYRF), an ER membrane-associated transcription factor (TF) released by self-cleavage. MYRF was expressed in the well-differentiated secretory cancer cells, but not in the poorly differentiated quasi-mesenchymal cells that coexist in the same tumor. MYRF expression was controlled by the epithelial identity TF HNF1B, and it acted to fine-tune the expression of genes encoding highly glycosylated, cysteine-rich secretory proteins, thus preventing ER overload. MYRF-deficient PDAC cells showed signs of ER stress, impaired proliferation, and an inability to form spheroids in vitro, while in vivo they generated highly secretory but poorly proliferating and hypocellular tumors. These data indicate a role of MYRF in the control of ER homeostasis in highly secretory PDAC cells.
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Affiliation(s)
- Marta Milan
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Milano, Italy
| | - Chiara Balestrieri
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Milano, Italy
| | - Gabriele Alfarano
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Milano, Italy
| | - Sara Polletti
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Milano, Italy
| | - Elena Prosperini
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Milano, Italy
| | - Paola Nicoli
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Milano, Italy
| | - Paola Spaggiari
- Humanitas Clinical Research Center IRCCS, Rozzano, Milano, Italy
| | - Alessandro Zerbi
- Humanitas Clinical Research Center IRCCS, Rozzano, Milano, Italy; Humanitas University, Pieve Emanuele, Milano, Italy
| | - Vincenzo Cirulli
- Departments of Medicine and Pharmacology, Institute for Stem Cell and Regenerative Medicine, UW Diabetes Institute, University of Washington, 850 Republican Street, Seattle, WA 98109, USA
| | - Giuseppe R Diaferia
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Milano, Italy.
| | - Gioacchino Natoli
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Milano, Italy; Humanitas University, Pieve Emanuele, Milano, Italy.
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