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Akiyoshi K, Fujimori T, Fu X, Shah AP, Yamaguchi A, Steenbergen C, Santhanam L, Berkowitz D, Tuday E, Baraban JM, Das S. Adenosine A 2A Receptor Regulates microRNA-181b Expression in Aorta: Therapeutic Implications for Large-Artery Stiffness. J Am Heart Assoc 2023:e028421. [PMID: 37421280 PMCID: PMC10382090 DOI: 10.1161/jaha.122.028421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 05/05/2023] [Indexed: 07/10/2023]
Abstract
Background The identification of large-artery stiffness as a major, independent risk factor for cardiovascular disease-associated morbidity and death has focused attention on identifying therapeutic strategies to combat this disorder. Genetic manipulations that delete or inactivate the translin/trax microRNA-degrading enzyme confer protection against aortic stiffness induced by chronic ingestion of high-salt water (4%NaCl in drinking water for 3 weeks) or associated with aging. Therefore, there is heightened interest in identifying interventions capable of inhibiting translin/trax RNase activity, as these may have therapeutic efficacy in large-artery stiffness. Methods and Results Activation of neuronal adenosine A2A receptors (A2ARs) triggers dissociation of trax from its C-terminus. As A2ARs are expressed by vascular smooth muscle cells (VSMCs), we investigated whether stimulation of A2AR on vascular smooth muscle cells promotes the association of translin with trax and, thereby increases translin/trax complex activity. We found that treatment of A7r5 cells with the A2AR agonist CGS21680 leads to increased association of trax with translin. Furthermore, this treatment decreases levels of pre-microRNA-181b, a target of translin/trax, and those of its downstream product, mature microRNA-181b. To check whether A2AR activation might contribute to high-salt water-induced aortic stiffening, we assessed the impact of daily treatment with the selective A2AR antagonist SCH58261 in this paradigm. We found that this treatment blocked aortic stiffening induced by high-salt water. Further, we confirmed that the age-associated decline in aortic pre-microRNA-181b/microRNA-181b levels observed in mice also occurs in humans. Conclusions These findings suggest that further studies are warranted to evaluate whether blockade of A2ARs may have therapeutic potential in treating large-artery stiffness.
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Affiliation(s)
- Kei Akiyoshi
- Department of Anesthesiology and Critical Care Medicine Johns Hopkins School of Medicine Baltimore MD USA
| | - Tomonari Fujimori
- Department of Anesthesiology and Critical Care Medicine Johns Hopkins School of Medicine Baltimore MD USA
| | - Xiuping Fu
- Department of Intelligent Medical Engineering, School of Life Science Tiangong University Tianjin China
| | - Aparna P Shah
- Solomon H. Snyder Department of Neuroscience Johns Hopkins School of Medicine Baltimore MD USA
| | - Atsushi Yamaguchi
- Department of Cardiovascular Surgery, Saitama Medical Center Jichi Medical University Saitama Japan
| | | | - Lakshmi Santhanam
- Department of Anesthesiology and Critical Care Medicine Johns Hopkins School of Medicine Baltimore MD USA
| | - Dan Berkowitz
- Department of Anesthesiology and Perioperative Medicine The University of Alabama at Birmingham Birmingham AL USA
| | - Eric Tuday
- Division of Cardiovascular Medicine, Department of Internal Medicine, School of Medicine University of Utah Salt Lake City UT USA
- Geriatric Research, Education and Clinical Center VA Salt Lake City Health Care System Salt Lake City UT USA
| | - Jay M Baraban
- Department of Intelligent Medical Engineering, School of Life Science Tiangong University Tianjin China
- Department of Psychiatry and Behavioral Sciences Johns Hopkins School of Medicine Baltimore MD USA
| | - Samarjit Das
- Department of Anesthesiology and Critical Care Medicine Johns Hopkins School of Medicine Baltimore MD USA
- Department of Pathology Johns Hopkins School of Medicine Baltimore MD USA
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Translin facilitates RNA polymerase II dissociation and suppresses genome instability during RNase H2- and Dicer-deficiency. PLoS Genet 2022; 18:e1010267. [PMID: 35714159 PMCID: PMC9246224 DOI: 10.1371/journal.pgen.1010267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 06/30/2022] [Accepted: 05/19/2022] [Indexed: 11/25/2022] Open
Abstract
The conserved nucleic acid binding protein Translin contributes to numerous facets of mammalian biology and genetic diseases. It was first identified as a binder of cancer-associated chromosomal translocation breakpoint junctions leading to the suggestion that it was involved in genetic recombination. With a paralogous partner protein, Trax, Translin has subsequently been found to form a hetero-octomeric RNase complex that drives some of its functions, including passenger strand removal in RNA interference (RNAi). The Translin-Trax complex also degrades the precursors to tumour suppressing microRNAs in cancers deficient for the RNase III Dicer. This oncogenic activity has resulted in the Translin-Trax complex being explored as a therapeutic target. Additionally, Translin and Trax have been implicated in a wider range of biological functions ranging from sleep regulation to telomere transcript control. Here we reveal a Trax- and RNAi-independent function for Translin in dissociating RNA polymerase II from its genomic template, with loss of Translin function resulting in increased transcription-associated recombination and elevated genome instability. This provides genetic insight into the longstanding question of how Translin might influence chromosomal rearrangements in human genetic diseases and provides important functional understanding of an oncological therapeutic target. Human genetic diseases, including cancers, are frequently driven by substantial changes to chromosomes, including translocations, where one arm of a chromosome is exchanged for another. The human nucleic acid binding protein Translin was first identified by its ability to bind to the chromosomal sites at which some of these translocations occur. This resulted in Translin being implicated in the mechanism that generated the translocation and thus the associated disease state. However, since its discovery there has been little evidence to directly indicate Translin does contribute to this process. It is, however, known to contribute to a number of biological functions including, amongst others, neurological regulation, sleep control, vascular stiffening, cancer immunomodulation and it has been recently identified as a potential therapeutic target in some cancers. Here we demonstrate that Translin has conserved function in genome stability maintenance when other primary pathways are defective, a function independent of a key binding partner protein, Trax. Specifically, we demonstrate that Translin contributes to minimizing the deleterious genome destabilizing effects of retaining gene expression machineries on chromosomes. This offers the first evidence for how Translin might contribute to genetic disease-causing chromosomal changes and offers insight to inform therapeutic design.
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Baraban JM, Tuday E, Berkowitz DE, Das S. Deciphering the Role of microRNAs in Large-Artery Stiffness Associated With Aging: Focus on miR-181b. Front Physiol 2021; 12:747789. [PMID: 34646165 PMCID: PMC8504676 DOI: 10.3389/fphys.2021.747789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 08/30/2021] [Indexed: 11/13/2022] Open
Abstract
Large artery stiffness (LAS) is a major, independent risk factor underlying cardiovascular disease that increases with aging. The emergence of microRNA signaling as a key regulator of vascular structure and function has stimulated interest in assessing its role in the pathophysiology of LAS. Identification of several microRNAs that display age-associated changes in expression in aorta has focused attention on defining their molecular targets and deciphering their role in age-associated arterial stiffening. Inactivation of the microRNA-degrading enzyme, translin/trax, which reverses the age-dependent decline in miR-181b, confers protection from aging-associated arterial stiffening, suggesting that inhibitors targeting this enzyme may have translational potential. As LAS poses a major public health challenge, we anticipate that future studies based on these advances will yield innovative strategies to combat aging-associated arterial stiffening.
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Affiliation(s)
- Jay M Baraban
- Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, ML, United States
| | - Eric Tuday
- Division of Cardiovascular Medicine, Department of Internal Medicine, School of Medicine, University of Utah, Salt Lake City, UT, United States.,Geriatric Research, Education and Clinical Center, VA Salt Lake City Health Care System, Salt Lake City, UT, United States
| | - Dan E Berkowitz
- Department of Anesthesiology and Perioperative Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Sam Das
- Department of Pathology, School of Medicine, Johns Hopkins University, Baltimore, ML, United States.,Department of Anesthesiology and Critical Care Medicine, Johns Hopkins Medicine, Baltimore, ML, United States
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Exosomes from Adipose Tissues Derived Mesenchymal Stem Cells Overexpressing MicroRNA-146a Alleviate Diabetic Osteoporosis in Rats. Cell Mol Bioeng 2021; 15:87-97. [DOI: 10.1007/s12195-021-00699-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Accepted: 08/18/2021] [Indexed: 12/23/2022] Open
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Fu X, Shah AP, Keighron J, Mou TCM, Ladenheim B, Alt J, Fukudome D, Niwa M, Tamashiro KL, Tanda G, Sawa A, Cadet JL, Rais R, Baraban JM. Elevated body fat increases amphetamine accumulation in brain: evidence from genetic and diet-induced forms of adiposity. Transl Psychiatry 2021; 11:427. [PMID: 34392304 PMCID: PMC8364554 DOI: 10.1038/s41398-021-01547-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/22/2021] [Accepted: 08/04/2021] [Indexed: 12/03/2022] Open
Abstract
Despite the high prevalence of obesity, little is known about its potential impact on the pharmacokinetics of psychotropic drugs. In the course of investigating the role of the microRNA system on neuronal signaling, we found that mice lacking the translin/trax microRNA-degrading enzyme display an exaggerated locomotor response to amphetamine. As these mice display robust adiposity in the context of normal body weight, we checked whether this phenotype might reflect elevated brain levels of amphetamine. To assess this hypothesis, we compared plasma and brain amphetamine levels of wild type and Tsn KO mice. Furthermore, we checked the effect of diet-induced increases in adiposity on plasma and brain amphetamine levels in wild type mice. Brain amphetamine levels were higher in Tsn KO mice than in wild type littermates and correlated with adiposity. Analysis of the effect of diet-induced increases in adiposity in wild type mice on brain amphetamine levels also demonstrated that brain amphetamine levels correlate with adiposity. Increased adiposity displayed by Tsn KO mice or by wild type mice fed a high-fat diet correlates with elevated brain amphetamine levels. As amphetamine and its analogues are widely used to treat attention deficit disorder, which is associated with obesity, further studies are warranted to assess the impact of adiposity on amphetamine levels in these patients.
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Affiliation(s)
- Xiuping Fu
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA
| | - Aparna P Shah
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA
| | - Jacqueline Keighron
- Medication Development Program, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, MD, 21224, USA
| | - Ta-Chung M Mou
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA
| | - Bruce Ladenheim
- Molecular Neuropsychiatry Research Branch, Intramural Research Program, NIDA/NIH/DHHS, 251 Bayview Boulevard, Baltimore, MD, 21224, USA
| | - Jesse Alt
- John Hopkins Drug Discovery, Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA
| | - Daisuke Fukudome
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA
| | - Minae Niwa
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, 35233, USA
| | - Kellie L Tamashiro
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA
| | - Gianluigi Tanda
- Medication Development Program, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, MD, 21224, USA
| | - Akira Sawa
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA
| | - Jean-Lud Cadet
- Molecular Neuropsychiatry Research Branch, Intramural Research Program, NIDA/NIH/DHHS, 251 Bayview Boulevard, Baltimore, MD, 21224, USA
| | - Rana Rais
- John Hopkins Drug Discovery, Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA
| | - Jay M Baraban
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA.
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA.
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Mews P, Calipari ES, Day J, Lobo MK, Bredy T, Abel T. From Circuits to Chromatin: The Emerging Role of Epigenetics in Mental Health. J Neurosci 2021; 41:873-882. [PMID: 33446519 PMCID: PMC7880276 DOI: 10.1523/jneurosci.1649-20.2020] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 12/19/2020] [Accepted: 12/22/2020] [Indexed: 02/01/2023] Open
Abstract
A central goal of neuroscience research is to understand how experiences modify brain circuits to guide future adaptive behavior. In response to environmental stimuli, neural circuit activity engages gene regulatory mechanisms within each cell. This activity-dependent gene expression is governed, in part, by epigenetic processes that can produce persistent changes in both neural circuits and the epigenome itself. The complex interplay between circuit activity and neuronal gene regulation is vital to learning and memory, and, when disrupted, is linked to debilitating psychiatric conditions, such as substance use disorder. To develop clinical treatments, it is paramount to advance our understanding of how neural circuits and the epigenome cooperate to produce behavioral adaptation. Here, we discuss how new genetic tools, used to manipulate neural circuits and chromatin, have enabled the discovery of epigenetic processes that bring about long-lasting changes in behavior relevant to mental health and disease.
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Affiliation(s)
- Philipp Mews
- Friedman Brain Institute, Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York 10129
| | - Erin S Calipari
- Departments of Pharmacology, Molecular Physiology and Biophysics, Psychiatry and Behavioral Sciences; Vanderbilt Center for Addiction Research; Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee 37323
| | - Jeremy Day
- Department of Neurobiology, McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, Alabama 35294
| | - Mary Kay Lobo
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Timothy Bredy
- Queensland Brain Institute, University of Queensland, Brisbane, 4072, Australia
| | - Ted Abel
- Department of Neuroscience and Pharmacology, Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242
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Park AJ, Shetty MS, Baraban JM, Abel T. Selective role of the translin/trax RNase complex in hippocampal synaptic plasticity. Mol Brain 2020; 13:145. [PMID: 33172471 PMCID: PMC7653721 DOI: 10.1186/s13041-020-00691-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 10/30/2020] [Indexed: 01/09/2023] Open
Abstract
Activity-dependent local protein synthesis is critical for synapse-specific, persistent plasticity. Abnormalities in local protein synthesis have been implicated in psychiatric disorders. We have recently identified the translin/trax microRNA-degrading enzyme as a novel mediator of protein synthesis at activated synapses. Additionally, translin knockout (KO) mice, which lack translin/trax, exhibit some of the behavioral abnormalities found in a mouse model of fragile X syndrome (fragile X mental retardation protein-FMRP-KO mice). Therefore, identifying signaling pathways interacting with translin/trax to support persistent synaptic plasticity is a translationally relevant goal. Here, as a first step to achieve this goal, we have assessed the requirement of translin/trax for multiple hippocampal synaptic plasticity paradigms that rely on distinct molecular mechanisms. We found that mice lacking translin/trax exhibited selective impairment in a form of persistent hippocampal plasticity, which requires postsynaptic protein kinase A (PKA) activity. In contrast, enduring forms of plasticity that are dependent on presynaptic PKA were unaffected. Furthermore, these mice did not display exaggerated metabotropic glutamate receptor-mediated long-term synaptic depression (mGluR-LTD), a hallmark of the FMRP KO mice. On the contrary, translin KO mice exhibited deficits in N-methyl-d-aspartate receptor (NMDAR) dependent LTD, a phenotype not observed in the FMRP knockouts. Taken together, these findings demonstrate that translin/trax mediates long-term synaptic plasticity that is dependent on postsynaptic PKA signaling and suggest that translin/trax and FMRP play distinct roles in hippocampal synaptic plasticity.
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Affiliation(s)
- Alan Jung Park
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA. .,Gogos Lab, Mortimer B. Zuckerman Mind Brain Behavior Institute, Jerome L. Greene Science Center, Columbia University, L5-053, 3227 Broadway, New York, NY, 10027, USA.
| | - Mahesh Shivarama Shetty
- Department of Neuroscience and Pharmacology, Carver College of Medicine, University of Iowa, 2-471 Bowen Science Building, 51 Newton Road, Iowa City, IA, 52242, USA.,Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, 2312 Pappajohn Biomedical Discovery Building, 169 Newton Road, Iowa City, 52242, IA, USA
| | - Jay M Baraban
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ted Abel
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA. .,Department of Neuroscience and Pharmacology, Carver College of Medicine, University of Iowa, 2-471 Bowen Science Building, 51 Newton Road, Iowa City, IA, 52242, USA. .,Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, 2312 Pappajohn Biomedical Discovery Building, 169 Newton Road, Iowa City, 52242, IA, USA.
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Fu X, Shah AP, Li Z, Li M, Tamashiro KL, Baraban JM. Genetic inactivation of the translin/trax microRNA-degrading enzyme phenocopies the robust adiposity induced by Translin (Tsn) deletion. Mol Metab 2020; 40:101013. [PMID: 32408014 PMCID: PMC7305343 DOI: 10.1016/j.molmet.2020.101013] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 04/22/2020] [Accepted: 05/04/2020] [Indexed: 12/14/2022] Open
Abstract
Objective Deletion of Translin (Tsn) from mice induces an unusual metabolic profile characterized by robust adiposity, normal body weight and glucose tolerance. Translin (TN) protein and its partner, trax (TX), form the TN/TX microRNA-degrading enzyme. Since the microRNA system plays a prominent role in regulating metabolism, we reasoned that the metabolic profile displayed by Tsn KO mice might reflect dysregulation of microRNA signaling. Methods To test this hypothesis, we inserted a mutation, E126A, in Tsnax, the gene encoding TX, that abolishes the microRNA-degrading enzymatic activity of the TN/TX complex. In addition, to help define the cell types that drive the adiposity phenotype, we have also generated mice with floxed alleles of Tsn or Tsnax. Results Introduction of the E126A mutation in Tsnax does not impair expression of TN or TX proteins or their co-precipitation. Furthermore, these mice display selective increases in microRNAs that match those induced by Tsn deletion, confirming that this mutation in Tsnax inactivates the microRNA-degrading activity of the TN/TX complex. Mice homozygous for the Tsnax (E126A) mutation display a metabolic profile that closely mimics that of Tsn KO mice. Selective deletion of Tsn or Tsnax from either adipocytes or hepatocytes, two candidate cell types, does not phenocopy the elevated adiposity displayed by mice with constitutive Tsn deletion or the Tsnax (E126A) mutation. Furthermore, global, conditional deletion of Tsn in adulthood does not elicit increased adiposity. Conclusion Taken together, these findings indicate that inactivation of the TN/TX microRNA-degrading enzyme during development is necessary to drive the robust adiposity displayed by Tsn KO mice. We inactivated the microRNA-degrading enzyme translin/trax in mice. These mice phenocopy the robust adiposity displayed by Tsn KO mice. Global conditional deletion of Tsn during adulthood does not elicit robust adiposity. Thus, loss of translin/trax activity in development mediates robust adiposity.
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Affiliation(s)
- Xiuping Fu
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA.
| | - Aparna P Shah
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA.
| | - Zhi Li
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA.
| | - Mengni Li
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA.
| | - Kellie L Tamashiro
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA.
| | - Jay M Baraban
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA.
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Henry TW, Mendoza FA, Jimenez SA. Role of microRNA in the pathogenesis of systemic sclerosis tissue fibrosis and vasculopathy. Autoimmun Rev 2019; 18:102396. [PMID: 31520794 DOI: 10.1016/j.autrev.2019.102396] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 05/07/2019] [Indexed: 12/11/2022]
Abstract
Systemic Sclerosis (SSc) pathogenesis involves multiple immunological, vascular and fibroproliferative abnormalities that contribute to a severe and complex clinical picture. Vasculopathy and fibroproliferative alterations are two hallmark pathological processes in SSc that are responsible for the most severe clinical manifestations of the disease and determine its clinical outcome and mortality. However, the pathogenesis of SSc vasculopathy and of the uncontrolled SSc fibrotic process remain incompletely understood. Recent investigations into the molecular pathways involved in these processes have identified an important role for epigenetic processes that contribute to overall disease progression and have emphasized microRNAs (miRNAs) as crucial epigenetic regulators. MiRNAs hold unique potential for elucidating SSc pathogenesis, improving diagnosis and developing effective targeted therapies for the disease. This review examines the important role that miRNAs play in the development and regulation of vascular and fibroproliferative alterations associated with SSc pathogenesis and their possible participation in the establishment of pathogenetic connections between these two processes. This review also emphasizes that further understanding of the involvement of miRNA in SSc fibrosis and vasculopathy will very likely provide novel future research directions and allow for the identification of groundbreaking therapeutic interventions within these processes. MiR-21, miR- 31, and miR-155 are of particular interest owing to their important involvement in both SSc vasculopathy and fibroproliferative alterations.
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Affiliation(s)
- Tyler W Henry
- Jefferson Institute of Molecular Medicine and Scleroderma Center, Thomas Jefferson University, Philadelphia 19107, USA; Sidney Kimmel Medical College, Thomas Jefferson University, USA
| | - Fabian A Mendoza
- Jefferson Institute of Molecular Medicine and Scleroderma Center, Thomas Jefferson University, USA; Division of Rheumatology, Department of Medicine, Thomas Jefferson University, USA
| | - Sergio A Jimenez
- Jefferson Institute of Molecular Medicine and Scleroderma Center, Thomas Jefferson University, USA.
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Deletion of translin (Tsn) induces robust adiposity and hepatic steatosis without impairing glucose tolerance. Int J Obes (Lond) 2019; 44:254-266. [PMID: 30647452 PMCID: PMC6629527 DOI: 10.1038/s41366-018-0315-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 12/06/2018] [Accepted: 12/14/2018] [Indexed: 02/06/2023]
Abstract
Objective: Translin knockout (KO) mice display robust adiposity. Recent studies indicate that translin and its partner protein, trax, regulate the microRNA and ATM kinase signaling pathways, both of which have been implicated in regulating metabolism. In the course of characterizing the metabolic profile of these mice, we found that they display normal glucose tolerance despite their elevated adiposity. Accordingly, we investigated why translin KO mice display this paradoxical phenotype. Methods: To help distinguish between the metabolic effects of increased adiposity and those of translin deletion per se, we compared three groups: (1) wild-type (WT), (2) translin KO mice on a standard chow diet, and (3) adiposity-matched WT mice that were placed on a high-fat diet until they matched translin KO adiposity levels. All groups were scanned to determine their body composition and tested to evaluate their glucose and insulin tolerance. Plasma, hepatic and adipose tissue samples were collected and used for histological and molecular analyses. Results: Translin KO mice show normal glucose tolerance whereas adiposity-matched WT mice, placed on a high-fat diet, do not. In addition, translin KO mice display prominent hepatic steatosis that is more severe than that of adiposity-matched WT mice. Unlike adiposity-matched WT mice, translin KO mice display three key features that have been shown to reduce susceptibility to insulin resistance: increased accumulation of subcutaneous fat, increased levels of circulating adiponectin and decreased Tnfα expression in hepatic and adipose tissue. Conclusions: The ability of translin KO mice to retain normal glucose tolerance in the face of marked adipose tissue expansion may be due to the three protective factors noted above. Further studies aimed at defining the molecular bases for this combination of protective phenotypes may yield new approaches to limit the adverse metabolic consequences of obesity.
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