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Song J, Zhang Y, Frieler RA, Andren A, Wood S, Tyrrell DJ, Sajjakulnukit P, Deng JC, Lyssiotis CA, Mortensen RM, Salmon M, Goldstein DR. Itaconate suppresses atherosclerosis by activating a Nrf2-dependent antiinflammatory response in macrophages in mice. J Clin Invest 2023; 134:e173034. [PMID: 38085578 PMCID: PMC10849764 DOI: 10.1172/jci173034] [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: 06/22/2023] [Accepted: 12/06/2023] [Indexed: 01/22/2024] Open
Abstract
Itaconate has emerged as a critical immunoregulatory metabolite. Here, we examined the therapeutic potential of itaconate in atherosclerosis. We found that both itaconate and the enzyme that synthesizes it, aconitate decarboxylase 1 (Acod1, also known as immune-responsive gene 1 [IRG1]), are upregulated during atherogenesis in mice. Deletion of Acod1 in myeloid cells exacerbated inflammation and atherosclerosis in vivo and resulted in an elevated frequency of a specific subset of M1-polarized proinflammatory macrophages in the atherosclerotic aorta. Importantly, Acod1 levels were inversely correlated with clinical occlusion in atherosclerotic human aorta specimens. Treating mice with the itaconate derivative 4-octyl itaconate attenuated inflammation and atherosclerosis induced by high cholesterol. Mechanistically, we found that the antioxidant transcription factor, nuclear factor erythroid 2-related factor 2 (Nrf2), was required for itaconate to suppress macrophage activation induced by oxidized lipids in vitro and to decrease atherosclerotic lesion areas in vivo. Overall, our work shows that itaconate suppresses atherogenesis by inducing Nrf2-dependent inhibition of proinflammatory responses in macrophages. Activation of the itaconate pathway may represent an important approach to treat atherosclerosis.
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Affiliation(s)
- Jianrui Song
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Yanling Zhang
- Department of Biochemistry and Molecular Biology, Soochow University Medical College, Suzhou, Jiangsu, China
| | - Ryan A. Frieler
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Anthony Andren
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Sherri Wood
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Daniel J. Tyrrell
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
- Department of Pathology, Heersink School of Medicine, University of Alabama at Birmingham, Alabama, USA
| | - Peter Sajjakulnukit
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
- University of Michigan Rogel Cancer Center
| | - Jane C. Deng
- Graduate Program in Immunology, and
- Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine, University of Michigan, Ann Arbor, Michigan, USA
- Veterans Affairs Ann Arbor Healthcare System, Ann Arbor, Michigan, USA
| | - Costas A. Lyssiotis
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
- Veterans Affairs Ann Arbor Healthcare System, Ann Arbor, Michigan, USA
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Richard M. Mortensen
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
- Department of Pharmacology
- Department of Internal Medicine, Division of Metabolism, Endocrinology, and Diabetes
| | | | - Daniel R. Goldstein
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
- Graduate Program in Immunology, and
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA
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Lei I, Huang W, Noly PE, Naik S, Ghali M, Liu L, Pagani FD, Abou El Ela A, Pober JS, Pitt B, Platt JL, Cascalho M, Wang Z, Chen YE, Mortensen RM, Tang PC. Metabolic reprogramming by immune-responsive gene 1 up-regulation improves donor heart preservation and function. Sci Transl Med 2023; 15:eade3782. [PMID: 36753565 PMCID: PMC10068866 DOI: 10.1126/scitranslmed.ade3782] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Preservation quality of donor hearts is a key determinant of transplant success. Preservation duration beyond 4 hours is associated with primary graft dysfunction (PGD). Given transport time constraints, geographical limitations exist for donor-recipient matching, leading to donor heart underutilization. Here, we showed that metabolic reprogramming through up-regulation of the enzyme immune response gene 1 (IRG1) and its product itaconate improved heart function after prolonged preservation. Irg1 transcript induction was achieved by adding the histone deacetylase (HDAC) inhibitor valproic acid (VPA) to a histidine-tryptophan-ketoglutarate solution used for donor heart preservation. VPA increased acetylated H3K27 occupancy at the IRG1 enhancer and IRG1 transcript expression in human donor hearts. IRG1 converts aconitate to itaconate, which has both anti-inflammatory and antioxidant properties. Accordingly, our studies showed that Irg1 transcript up-regulation by VPA treatment increased nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) in mice, which was accompanied by increased antioxidant protein expression [hemeoxygenase 1 (HO1) and superoxide dismutase 1 (SOD1)]. Deletion of Irg1 in mice (Irg1-/-) negated the antioxidant and cardioprotective effects of VPA. Consistent with itaconate's ability to inhibit succinate dehydrogenase, VPA treatment of human hearts increased itaconate availability and reduced succinate accumulation during preservation. VPA similarly increased IRG1 expression in pig donor hearts and improved its function in an ex vivo cardiac perfusion system both at the clinical 4-hour preservation threshold and at 10 hours. These results suggest that augmentation of cardioprotective immune-metabolomic pathways may be a promising therapeutic strategy for improving donor heart function in transplantation.
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Affiliation(s)
- Ienglam Lei
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI 48109, USA
| | - Wei Huang
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI 48109, USA
| | - Pierre Emmanuel Noly
- Department of Cardiac Surgery, Université de Montréal, Montréal, Quebec H1T 1C8, Canada
| | - Suyash Naik
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI 48109, USA
| | - Miriyam Ghali
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI 48109, USA
| | - Liu Liu
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI 48109, USA
| | - Francis D Pagani
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI 48109, USA
| | - Ashraf Abou El Ela
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jordan S Pober
- Department of Pathology, Yale University, New Haven, CT 06510, USA
| | - Bertram Pitt
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jeffrey L Platt
- Department of Surgery, University of Michigan, Ann Arbor, MI 48109, USA
| | - Marilia Cascalho
- Department of Surgery, University of Michigan, Ann Arbor, MI 48109, USA
| | - Zhong Wang
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI 48109, USA
| | - Y Eugene Chen
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI 48109, USA
| | - Richard M Mortensen
- Departments of Molecular and Integrative Physiology, Internal Medicine, and Pharmacology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Paul C Tang
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI 48109, USA
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3
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Frieler RA, Vigil TM, Song J, Leung C, Goldstein DR, Lumeng CN, Mortensen RM. Aconitate decarboxylase 1 regulates glucose homeostasis and obesity in mice. Obesity (Silver Spring) 2022; 30:1818-1830. [PMID: 35927796 PMCID: PMC9541899 DOI: 10.1002/oby.23509] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 05/12/2022] [Accepted: 05/16/2022] [Indexed: 01/31/2023]
Abstract
OBJECTIVE The intersection between immunology and metabolism contributes to the pathogenesis of obesity-associated metabolic diseases as well as molecular control of inflammatory responses. The metabolite itaconate and the cell-permeable derivatives have robust anti-inflammatory effects; therefore, it is hypothesized that cis-aconitate decarboxylase (Acod1)-produced itaconate has a protective, anti-inflammatory effect during diet-induced obesity and metabolic disease. METHODS Wild-type and Acod1-/- mice were subjected to diet-induced obesity. Glucose metabolism was analyzed by glucose tolerance tests, insulin tolerance tests, and indirect calorimetry. Gene expression and transcriptome analysis was performed using quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and RNA sequencing. RESULTS Wild-type and Acod1-/- mice on high-fat diet had equivalent weight gain, but Acod1-/- mice had impaired glucose metabolism. Insulin tolerance tests and glucose tolerance tests after 12 weeks on high-fat diet revealed significantly higher blood glucose levels in Acod1-/- mice. This was associated with significant enrichment of inflammatory gene sets and a reduction in genes related to adipogenesis and fatty acid metabolism. Analysis of naive Acod1-/- mice showed a significant increase in fat deposition at 3 and 6 months of age and obesity and insulin resistance by 12 months. CONCLUSIONS The data show that Acod1 has an important role in the regulation of glucose homeostasis and obesity under normal and high-fat diet conditions.
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Affiliation(s)
- Ryan A. Frieler
- Department of Molecular and Integrative PhysiologyUniversity of Michigan Medical SchoolAnn ArborMichiganUSA
| | - Thomas M. Vigil
- Department of Molecular and Integrative PhysiologyUniversity of Michigan Medical SchoolAnn ArborMichiganUSA
| | - Jianrui Song
- Department of Internal Medicine, Division of Cardiovascular MedicineUniversity of Michigan Medical SchoolAnn ArborMichiganUSA
| | - Christy Leung
- Department of Molecular and Integrative PhysiologyUniversity of Michigan Medical SchoolAnn ArborMichiganUSA
| | - Daniel R. Goldstein
- Department of Internal Medicine, Division of Cardiovascular MedicineUniversity of Michigan Medical SchoolAnn ArborMichiganUSA
| | - Carey N. Lumeng
- Department of Molecular and Integrative PhysiologyUniversity of Michigan Medical SchoolAnn ArborMichiganUSA
- Department of Pediatrics and Communicable DiseasesUniversity of Michigan Medical SchoolAnn ArborMichiganUSA
| | - Richard M. Mortensen
- Department of Molecular and Integrative PhysiologyUniversity of Michigan Medical SchoolAnn ArborMichiganUSA
- Department of Internal Medicine, Division of Metabolism, Endocrinology, and DiabetesUniversity of Michigan Medical SchoolAnn ArborMichiganUSA
- Department of PharmacologyUniversity of Michigan Medical SchoolAnn ArborMichiganUSA
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4
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Inazumi H, Kuwahara K, Nakagawa Y, Kuwabara Y, Numaga-Tomita T, Kashihara T, Nakada T, Kurebayashi N, Oya M, Nonaka M, Sugihara M, Kinoshita H, Moriuchi K, Yanagisawa H, Nishikimi T, Motoki H, Yamada M, Morimoto S, Otsu K, Mortensen RM, Nakao K, Kimura T. NRSF- GNAO1 Pathway Contributes to the Regulation of Cardiac Ca 2+ Homeostasis. Circ Res 2022; 130:234-248. [PMID: 34875852 DOI: 10.1161/circresaha.121.318898] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [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] [Indexed: 12/24/2022]
Abstract
BACKGROUND During the development of heart failure, a fetal cardiac gene program is reactivated and accelerates pathological cardiac remodeling. We previously reported that a transcriptional repressor, NRSF (neuron restrictive silencer factor), suppresses the fetal cardiac gene program, thereby maintaining cardiac integrity. The underlying molecular mechanisms remain to be determined, however. METHODS We aim to elucidate molecular mechanisms by which NRSF maintains normal cardiac function. We generated cardiac-specific NRSF knockout mice and analyzed cardiac gene expression profiles in those mice and mice cardiac-specifically expressing a dominant-negative NRSF mutant. RESULTS We found that cardiac expression of Gαo, an inhibitory G protein encoded in humans by GNAO1, is transcriptionally regulated by NRSF and is increased in the ventricles of several mouse models of heart failure. Genetic knockdown of Gnao1 ameliorated the cardiac dysfunction and prolonged survival rates in these mouse heart failure models. Conversely, cardiac-specific overexpression of GNAO1 in mice was sufficient to induce cardiac dysfunction. Mechanistically, we observed that increasing Gαo expression increased surface sarcolemmal L-type Ca2+ channel activity, activated CaMKII (calcium/calmodulin-dependent kinase-II) signaling, and impaired Ca2+ handling in ventricular myocytes, which led to cardiac dysfunction. CONCLUSIONS These findings shed light on a novel function of Gαo in the regulation of cardiac Ca2+ homeostasis and systolic function and suggest Gαo may be an effective therapeutic target for the treatment of heart failure.
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Affiliation(s)
- Hideaki Inazumi
- Cardiovascular Medicine (H.I., Y.N., H.K., K.M., H.Y., T. Nishikimi, T. Kimura), Graduate School of Medicine, Kyoto University
| | - Koichiro Kuwahara
- Cardiovascular Medicine (K.K., M.O., H.M.), School of Medicine, Shinshu University, Matsumoto
| | - Yasuaki Nakagawa
- Cardiovascular Medicine (H.I., Y.N., H.K., K.M., H.Y., T. Nishikimi, T. Kimura), Graduate School of Medicine, Kyoto University
| | - Yoshihiro Kuwabara
- Center for Accessing Early Promising Treatment, Kyoto University Hospital (Y.K.)
| | - Takuro Numaga-Tomita
- Molecular Pharmacology (T.N.-T., M.Y.), School of Medicine, Shinshu University, Matsumoto
| | - Toshihide Kashihara
- Molecular Pharmacology, School of Pharmaceutical Sciences, Kitasato University, Tokyo (T. Kashihara)
| | - Tsutomu Nakada
- Research Center for Supports to Advanced Science (T. Nakada), School of Medicine, Shinshu University, Matsumoto
| | - Nagomi Kurebayashi
- Cellular and Molecular Pharmacology, School of Medicine, Juntendo University, Tokyo (N.K.)
| | - Miku Oya
- Cardiovascular Medicine (K.K., M.O., H.M.), School of Medicine, Shinshu University, Matsumoto
| | - Miki Nonaka
- Pain Control Research, The Jikei University School of Medicine (M.N.)
| | - Masami Sugihara
- Clinical Laboratory Medicine, School of Medicine, Juntendo University, Tokyo (M.S.)
| | - Hideyuki Kinoshita
- Cardiovascular Medicine (H.I., Y.N., H.K., K.M., H.Y., T. Nishikimi, T. Kimura), Graduate School of Medicine, Kyoto University
| | - Kenji Moriuchi
- Cardiovascular Medicine (H.I., Y.N., H.K., K.M., H.Y., T. Nishikimi, T. Kimura), Graduate School of Medicine, Kyoto University
| | | | - Toshio Nishikimi
- Cardiovascular Medicine (H.I., Y.N., H.K., K.M., H.Y., T. Nishikimi, T. Kimura), Graduate School of Medicine, Kyoto University
- Wakakusa Tatsuma Rehabilitation Hospital, Osaka (T. Nishikimi)
| | - Hirohiko Motoki
- Cardiovascular Medicine (K.K., M.O., H.M.), School of Medicine, Shinshu University, Matsumoto
| | - Mitsuhiko Yamada
- Molecular Pharmacology (T.N.-T., M.Y.), School of Medicine, Shinshu University, Matsumoto
| | - Sachio Morimoto
- School of Health Sciences Fukuoka, International University of Health and Welfare, Okawa (S.M.)
| | - Kinya Otsu
- The School of Cardiovascular Medicine and Sciences, King's College London British Heart Foundation Centre of Excellence, United Kingdom (K.O.)
| | | | - Kazuwa Nakao
- Medical Innovation Center (K.N.), Graduate School of Medicine, Kyoto University
| | - Takeshi Kimura
- Cardiovascular Medicine (H.I., Y.N., H.K., K.M., H.Y., T. Nishikimi, T. Kimura), Graduate School of Medicine, Kyoto University
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Frieler RA, Vigil TM, Song J, Leung C, Lumeng CN, Mortensen RM. High-fat and high-sodium diet induces metabolic dysfunction in the absence of obesity. Obesity (Silver Spring) 2021; 29:1868-1881. [PMID: 34549547 PMCID: PMC8571049 DOI: 10.1002/oby.23264] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 07/09/2021] [Accepted: 07/13/2021] [Indexed: 11/10/2022]
Abstract
OBJECTIVE Excess dietary fat and sodium (NaCl) are both associated with obesity and metabolic dysfunction. In mice, high NaCl has been shown to block high-fat (HF) diet-induced weight gain. Here, the impact of an HF/NaCl diet on metabolic function in the absence of obesity was investigated. METHODS Wild-type mice were administered chow, NaCl (4%), HF, and HF/NaCl diets. Metabolic analysis was performed by measuring fasted blood glucose and insulin levels and by glucose tolerance test and insulin tolerance test. RESULTS After 10 weeks on diets, male and female mice on the HF diet gained weight, and HF/NaCl mice had significantly reduced weight gain similar to chow-fed mice. In the absence of obesity, HF/NaCl mice had significantly elevated fasting blood glucose and impaired glucose control during glucose tolerance tests. Both NaCl and HF/NaCl mice had decreased pancreas and β-cell mass. Administration of NaCl in drinking water did not protect mice from HF-diet-induced weight gain and obesity. Further analysis revealed that longer administration of HF/NaCl diets for 20 weeks resulted in significant weight gain and insulin resistance. CONCLUSIONS The data demonstrate that despite early inhibitory effects on fat deposition and weight gain, an HF/NaCl diet does not prevent the metabolic consequences of HF diet consumption.
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Affiliation(s)
- Ryan A. Frieler
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
| | - Thomas M. Vigil
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
| | - Jianrui Song
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
| | - Christy Leung
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
| | - Carey N. Lumeng
- Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor, MI
| | - Richard M. Mortensen
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
- Department of Internal Medicine, Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor, MI
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI
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6
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Vigil TM, Frieler RA, Kilpatrick KL, Wang MM, Mortensen RM. Aconitate decarboxylase 1 suppresses cerebral ischemia-reperfusion injury in mice. Exp Neurol 2021; 347:113902. [PMID: 34699789 PMCID: PMC8642300 DOI: 10.1016/j.expneurol.2021.113902] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [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: 07/01/2021] [Revised: 10/19/2021] [Accepted: 10/20/2021] [Indexed: 01/03/2023]
Abstract
Immunometabolic changes have been shown to be a key factor in determining the immune cell response in disease models. The immunometabolite, itaconate, is produced by aconitate decarboxylase 1 (Acod1) and has been shown to inhibit inflammatory signaling in macrophages. In this study, we explore the role of Acod1 and itaconate in cerebral ischemia/reperfusion injury. We assessed the effect of global Acod1 knockout (Acod1KO, loss of endogenous itaconate) in a transient ischemia/reperfusion occlusion stroke model. Mice received a transient 90-min middle cerebral artery occlusion followed with 24-h of reperfusion. Stroke lesion volume was measured by MRI analysis and brain tissues were collected for mRNA gene expression analysis. Acod1KO mice showed significant increases in lesion volume compared to control mice, however no differences in pro-inflammatory mRNA levels were observed. Cell specific knockout of Acod1 in myeloid cells (LysM-Cre), microglia cells (CX3CR1, Cre-ERT2) and Endothelial cells (Cdh5(PAC), Cre-ERT2) did not reproduce lesion volume changes seen in global Acod1KO, indicating that circulating myeloid cells, resident microglia and endothelial cell populations are not the primary contributors to the observed phenotype. These effects however do not appear to be driven by changes in inflammatory gene regulation. These data suggests that endogenous Acod1 is protective in cerebral ischemia/reperfusion injury.
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Affiliation(s)
- Thomas M. Vigil
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
| | - Ryan A. Frieler
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
| | - KiAundra L. Kilpatrick
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
| | - Michael M. Wang
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
| | - Richard M. Mortensen
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI,Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI,Department of Internal Medicine, Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor, MI
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7
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Lei I, Huang W, Ward PA, Pober JS, Tellides G, Ailawadi G, Pagani FD, Landstrom AP, Wang Z, Mortensen RM, Cascalho M, Platt J, Eugene Chen Y, Lam HYK, Tang PC. Differential inflammatory responses of the native left and right ventricle associated with donor heart preservation. Physiol Rep 2021; 9:e15004. [PMID: 34435466 PMCID: PMC8387788 DOI: 10.14814/phy2.15004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Revised: 07/14/2021] [Accepted: 07/18/2021] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Dysfunction and inflammation of hearts subjected to cold ischemic preservation may differ between left and right ventricles, suggesting distinct strategies for amelioration. METHODS AND RESULTS Explanted murine hearts subjected to cold ischemia for 0, 4, or 8 h in preservation solution were assessed for function during 60 min of warm perfusion and then analyzed for cell death and inflammation by immunohistochemistry and western blotting and total RNA sequencing. Increased cold ischemic times led to greater left ventricle (LV) dysfunction compared to right ventricle (RV). The LV experienced greater cell death assessed by TUNEL+ cells and cleaved caspase-3 expression (n = 4). While IL-6 protein levels were upregulated in both LV and RV, IL-1β, TNFα, IL-10, and MyD88 were disproportionately increased in the LV. Inflammasome components (NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3), adaptor molecule apoptosis-associated speck-like protein containing a CARD (ASC), cleaved caspase-1) and products (cleaved IL-1β and gasdermin D) were also more upregulated in the LV. Pathway analysis of RNA sequencing showed increased signaling related to tumor necrosis factor, interferon, and innate immunity with ex-vivo ischemia, but no significant differences were found between the LV and RV. Human donor hearts showed comparable inflammatory responses to cold ischemia with greater LV increases of TNFα, IL-10, and inflammasomes (n = 3). CONCLUSIONS Mouse hearts subjected to cold ischemia showed time-dependent contractile dysfunction and increased cell death, inflammatory cytokine expression and inflammasome expression that are greater in the LV than RV. However, IL-6 protein elevations and altered transcriptional profiles were similar in both ventricles. Similar changes are observed in human hearts.
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Affiliation(s)
- Ienglam Lei
- Department of Cardiac SurgeryUniversity of Michigan Frankel Cardiovascular CenterAnn ArborMichiganUSA
| | - Wei Huang
- Department of Cardiac SurgeryUniversity of Michigan Frankel Cardiovascular CenterAnn ArborMichiganUSA
| | - Peter A. Ward
- Department of PathologyUniversity of Michigan Medical SchoolAnn ArborMichiganUSA
| | - Jordan S. Pober
- Department of ImmunobiologyYale UniversityNew HavenConnecticutUSA
| | | | - Gorav Ailawadi
- Department of Cardiac SurgeryUniversity of Michigan Frankel Cardiovascular CenterAnn ArborMichiganUSA
| | - Francis D. Pagani
- Department of Cardiac SurgeryUniversity of Michigan Frankel Cardiovascular CenterAnn ArborMichiganUSA
| | | | - Zhong Wang
- Department of Cardiac SurgeryUniversity of Michigan Frankel Cardiovascular CenterAnn ArborMichiganUSA
| | - Richard M. Mortensen
- Department of Internal MedicineUniversity of Michigan Frankel Cardiovascular CenterAnn ArborMichiganUSA
| | - Marilia Cascalho
- Department of SurgeryUniversity of Michigan Medical SchoolAnn ArborMichiganUSA
| | - Jeffrey Platt
- Department of SurgeryUniversity of Michigan Medical SchoolAnn ArborMichiganUSA
| | - Yuqing Eugene Chen
- Department of Cardiac SurgeryUniversity of Michigan Frankel Cardiovascular CenterAnn ArborMichiganUSA
| | | | - Paul C. Tang
- Department of Cardiac SurgeryUniversity of Michigan Frankel Cardiovascular CenterAnn ArborMichiganUSA
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8
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Song J, Frieler RA, Vigil TM, Ma J, Brombacher F, Goonewardena SN, Goldstein DR, Mortensen RM. Inactivation of Interleukin-4 Receptor α Signaling in Myeloid Cells Protects Mice From Angiotensin II/High Salt-Induced Cardiovascular Dysfunction Through Suppression of Fibrotic Remodeling. J Am Heart Assoc 2021; 10:e017329. [PMID: 34132103 PMCID: PMC8403318 DOI: 10.1161/jaha.120.017329] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [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] [Indexed: 01/01/2023]
Abstract
Background Hypertension‐induced cardiovascular remodeling is characterized by chronic low‐grade inflammation. Interleukin‐4 receptor α (IL‐4Rα) signaling is importantly involved in cardiovascular remodeling, however, the target cell type(s) is unclear. Here, we investigated the role of myeloid‐specific IL‐4Rα signaling in cardiovascular remodeling induced by angiotensin II and high salt. Methods and Results Myeloid IL‐4Rα deficiency suppressed both the in vitro and in vivo expression of alternatively activated macrophage markers including Arg1 (arginase 1), Ym1 (chitinase 3‐like 3), and Relmα/Fizz1 (resistin‐like molecule α). After angiotensin II and high salt treatment, myeloid‐specific IL‐4Rα deficiency did not change hypertrophic remodeling within the heart and aorta. However, myeloid IL‐4Rα deficiency resulted in a substantial reduction in fibrosis through the suppression of profibrotic pathways and the enhancement of antifibrotic signaling. Decreased fibrosis was associated with significant preservation of myocardial function in MyIL4RαKO mice and was mediated by attenuated alternative macrophage activation. Conclusions Myeloid IL‐4Rα signaling is substantially involved in fibrotic cardiovascular remodeling by controlling alternative macrophage activation and regulating fibrosis‐related signaling. Inhibiting myeloid IL‐4Rα signaling may be a potential strategy to prevent hypertensive cardiovascular diseases.
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Affiliation(s)
- Jianrui Song
- Department of Cell and Developmental Biology University of Michigan Medical School Ann Arbor MI.,Department of Molecular and Integrative Physiology University of Michigan Ann Arbor MI
| | - Ryan A Frieler
- Department of Molecular and Integrative Physiology University of Michigan Ann Arbor MI
| | - Thomas M Vigil
- Department of Molecular and Integrative Physiology University of Michigan Ann Arbor MI
| | - Jun Ma
- Department of Thoracic Surgery Shanxi Province People's Hospital Taiyuan P.R. China
| | - Frank Brombacher
- International Center for Genetic Engineering and Biotechnology University of Cape TownDivision of Immunology and South African Medical Research Council (SAMRC) Cape Town South Africa
| | - Sascha N Goonewardena
- Division of Cardiovascular Medicine Department of Internal Medicine University of Michigan Ann Arbor MI
| | - Daniel R Goldstein
- Division of Cardiovascular Medicine Department of Internal Medicine University of Michigan Ann Arbor MI.,Institute of Gerontology University of Michigan Ann Arbor MI.,Department of Microbiology and Immunology University of Michigan Ann Arbor MI
| | - Richard M Mortensen
- Department of Molecular and Integrative Physiology University of Michigan Ann Arbor MI.,Division of Metabolism, Endocrinology, and Diabetes Department of Internal Medicine University of Michigan Ann Arbor MI.,Department of Pharmacology University of Michigan Ann Arbor MI
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9
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Song J, Frieler RA, Whitesall SE, Chung Y, Vigil TM, Muir LA, Ma J, Brombacher F, Goonewardena SN, Lumeng CN, Goldstein DR, Mortensen RM. Myeloid interleukin-4 receptor α is essential in postmyocardial infarction healing by regulating inflammation and fibrotic remodeling. Am J Physiol Heart Circ Physiol 2021; 320:H323-H337. [PMID: 33164548 PMCID: PMC7847075 DOI: 10.1152/ajpheart.00251.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [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: 04/14/2020] [Revised: 10/23/2020] [Accepted: 10/29/2020] [Indexed: 02/06/2023]
Abstract
Interleukin-4 receptor α (IL4Rα) signaling plays an important role in cardiac remodeling during myocardial infarction (MI). However, the target cell type(s) of IL4Rα signaling during this remodeling remains unclear. Here, we investigated the contribution of endogenous myeloid-specific IL4Rα signaling in cardiac remodeling post-MI. We established a murine myeloid-specific IL4Rα knockout (MyIL4RαKO) model with LysM promoter-driven Cre recombination. Macrophages from MyIL4RαKO mice showed significant downregulation of alternatively activated macrophage markers but an upregulation of classical activated macrophage markers both in vitro and in vivo, indicating the successful inactivation of IL4Rα signaling in macrophages. To examine the role of myeloid IL4Rα during MI, we subjected MyIL4RαKO and littermate floxed control (FC) mice to MI. We found that cardiac function was significantly impaired as a result of myeloid-specific IL4Rα deficiency. This deficiency resulted in a dysregulated inflammatory response consisting of decreased production of anti-inflammatory cytokines. Myeloid IL4Rα deficiency also led to reduced collagen 1 deposition and an imbalance of matrix metalloproteinases (MMPs)/tissue inhibitors of metalloproteinases (TIMPs), with upregulated MMPs and downregulated TIMPs, which resulted in insufficient fibrotic remodeling. In conclusion, this study identifies that myeloid-specific IL4Rα signaling regulates inflammation and fibrotic remodeling during MI. Therefore, myeloid-specific activation of IL4Rα signaling could offer protective benefits after MI.NEW & NOTEWORTHY This study showed, for the first time, the role of endogenous IL4Rα signaling in myeloid cells during cardiac remodeling and the underlying mechanisms. We identified myeloid cells are the critical target cell types of IL4Rα signaling during cardiac remodeling post-MI. Deficiency of myeloid IL4Rα signaling causes deteriorated cardiac function post-MI, due to dysregulated inflammation and insufficient fibrotic remodeling. This study sheds light on the potential of activating myeloid-specific IL4Rα signaling to modify remodeling post-MI. This brings hope to patients with MI and diminishes side effects by cell type-specific instead of whole body treatment.
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Affiliation(s)
- Jianrui Song
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan
| | - Ryan A Frieler
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Steven E Whitesall
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Yutein Chung
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Thomas M Vigil
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Lindsey A Muir
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, Michigan
| | - Jun Ma
- Department of Thoracic Surgery, Shanxi Province People's Hospital, Taiyuan, People's Republic of China
| | - Frank Brombacher
- International Center for Genetic Engineering and Biotechnology, University of Cape Town, Cape Town, South Africa
| | - Sascha N Goonewardena
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Carey N Lumeng
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, Michigan
| | - Daniel R Goldstein
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
- Institute of Gerontology, University of Michigan, Ann Arbor, Michigan
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan
| | - Richard M Mortensen
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
- Division of Metabolism, Endocrinology, and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan
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10
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Triner D, Devenport SN, Ramakrishnan SK, Ma X, Frieler RA, Greenson JK, Inohara N, Nunez G, Colacino JA, Mortensen RM, Shah YM. Neutrophils Restrict Tumor-Associated Microbiota to Reduce Growth and Invasion of Colon Tumors in Mice. Gastroenterology 2019; 156:1467-1482. [PMID: 30550822 PMCID: PMC6441634 DOI: 10.1053/j.gastro.2018.12.003] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 11/26/2018] [Accepted: 12/05/2018] [Indexed: 12/16/2022]
Abstract
BACKGROUND & AIMS Neutrophils are among the most prevalent immune cells in the microenvironment of colon tumors; they are believed to promote growth of colon tumors, and their numbers correlate with outcomes of patients with colon cancer. Trials of inhibitors of neutrophil trafficking are underway in patients with cancer, but it is not clear how neutrophils contribute to colon tumorigenesis. METHODS Colitis-associated colon cancer was induced in mice with conditional deletion of neutrophils (LysMCre;Mcl1fl/fl) and wild-type littermates (LysMCre;Mcl1wt/wt, control mice) by administration of azoxythmethane and/or dextran sulfate sodium. Sporadic colon tumorigenesis was assessed in neutrophil-deficient and neutrophil-replete mice with conditional deletion of colon epithelial Apc (Cdx2-CreERT2;Apcfl/fl). Primary colon tumor tissues from these mice were assessed by histology, RNA sequencing, quantitative polymerase chain reaction, and fluorescence in situ hybridization analyses. Fecal and tumor-associated microbiota were assessed by 16s ribosomal RNA sequencing. RESULTS In mice with inflammation-induced and sporadic colon tumors, depletion of neutrophils increased the growth, proliferation, and invasiveness of the tumors. RNA sequencing analysis identified genes that regulate antimicrobial and inflammatory processes that were dysregulated in neutrophil-deficient colon tumors compared with colon tumors from control mice. Neutrophil depletion correlated with increased numbers of bacteria in tumors and proliferation of tumor cells, tumor-cell DNA damage, and an inflammatory response mediated by interleukin 17 (IL17). The 16s ribosomal RNA sequencing identified significant differences in the composition of the microbiota between colon tumors from neutrophil-deficient vs control mice. Administration of antibiotics or a neutralizing antibody against IL17 to neutrophil-deficient mice resulted in development of less-invasive tumors compared with mice given vehicle. We found bacteria in tumors to induce production of IL17, which promotes influx of intratumor B cells that promote tumor growth and progression. CONCLUSIONS In comparisons of mice with vs without neutrophils, we found neutrophils to slow colon tumor growth and progression by restricting numbers of bacteria and tumor-associated inflammatory responses.
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Affiliation(s)
- Daniel Triner
- Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor MI
| | - Samantha N. Devenport
- Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor MI
| | | | - Xiaoya Ma
- Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor MI
| | - Ryan A. Frieler
- Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor MI
| | - Joel K. Greenson
- Department of Pathology, University of Michigan Medical School, Ann Arbor MI
| | - Naohiro Inohara
- Department of Pathology, University of Michigan Medical School, Ann Arbor MI
| | - Gabriel Nunez
- Department of Pathology, University of Michigan Medical School, Ann Arbor MI,Rogel Cancer Center, University of Michigan Medical School, Ann Arbor MI
| | - Justin A. Colacino
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor MI,Department of Nutritional Sciences, University of Michigan School of Public Health, Ann Arbor MI
| | - Richard M. Mortensen
- Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor MI,Internal Medicine Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor MI
| | - Yatrik M. Shah
- Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor MI,Internal Medicine Division of Gastroenterology, University of Michigan Medical School, Ann Arbor MI,Rogel Cancer Center, University of Michigan Medical School, Ann Arbor MI
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11
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Ramakrishnan SK, Zhang H, Ma X, Jung I, Schwartz AJ, Triner D, Devenport SN, Das NK, Xue X, Zeng MY, Hu Y, Mortensen RM, Greenson JK, Cascalho M, Wobus CE, Colacino JA, Nunez G, Rui L, Shah YM. Intestinal non-canonical NFκB signaling shapes the local and systemic immune response. Nat Commun 2019; 10:660. [PMID: 30737385 PMCID: PMC6368617 DOI: 10.1038/s41467-019-08581-8] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Accepted: 01/21/2019] [Indexed: 12/13/2022] Open
Abstract
Microfold cells (M-cells) are specialized cells of the intestine that sample luminal microbiota and dietary antigens to educate the immune cells of the intestinal lymphoid follicles. The function of M-cells in systemic inflammatory responses are still unclear. Here we show that epithelial non-canonical NFkB signaling mediated by NFkB-inducing kinase (NIK) is highly active in intestinal lymphoid follicles, and is required for M-cell maintenance. Intestinal NIK signaling modulates M-cell differentiation and elicits both local and systemic IL-17A and IgA production. Importantly, intestinal NIK signaling is active in mouse models of colitis and patients with inflammatory bowel diseases; meanwhile, constitutive NIK signaling increases the susceptibility to inflammatory injury by inducing ectopic M-cell differentiation and a chronic increase of IL-17A. Our work thus defines an important function of non-canonical NFkB and M-cells in immune homeostasis, inflammation and polymicrobial sepsis. Microfold cells (M-cell) are specialized cells of the intestine that sample luminal microbiota and dietary antigens. Here the authors show that epithelial non-canonical NFκB signalling, as induced by NIK, is important for M-cells maintenance, yet constitutive NIK activation is associated with gut inflammation and inflammatory bowel disease.
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Affiliation(s)
| | - Huabing Zhang
- Department of Molecular & Integrative Physiology, University of Michigan, Michigan, MI, 48109, USA
| | - Xiaoya Ma
- Department of Molecular & Integrative Physiology, University of Michigan, Michigan, MI, 48109, USA
| | - Inkyung Jung
- Department of Molecular & Integrative Physiology, University of Michigan, Michigan, MI, 48109, USA
| | - Andrew J Schwartz
- Department of Molecular & Integrative Physiology, University of Michigan, Michigan, MI, 48109, USA
| | - Daniel Triner
- Department of Molecular & Integrative Physiology, University of Michigan, Michigan, MI, 48109, USA
| | - Samantha N Devenport
- Department of Molecular & Integrative Physiology, University of Michigan, Michigan, MI, 48109, USA
| | - Nupur K Das
- Department of Molecular & Integrative Physiology, University of Michigan, Michigan, MI, 48109, USA
| | - Xiang Xue
- Department of Molecular & Integrative Physiology, University of Michigan, Michigan, MI, 48109, USA
| | - Melody Y Zeng
- Department of Pathology, University of Michigan, Ann Arbor, MI, 48109, USA.,Internal Medicine, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Yinling Hu
- Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD, 21702, USA
| | - Richard M Mortensen
- Department of Molecular & Integrative Physiology, University of Michigan, Michigan, MI, 48109, USA
| | - Joel K Greenson
- Department of Pathology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Marilia Cascalho
- Transplantation Biology, University of Michigan, Ann Arbor, MI, 48109, USA.,Department of Surgery, University of Michigan, Ann Arbor, MI, 48109, USA.,Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Christiane E Wobus
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Justin A Colacino
- Department of Environmental Health Sciences, University of Michigan, Ann Arbor, MI, 48109, USA.,Department of Nutritional Sciences, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Gabriel Nunez
- Department of Pathology, University of Michigan, Ann Arbor, MI, 48109, USA.,Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Liangyou Rui
- Department of Molecular & Integrative Physiology, University of Michigan, Michigan, MI, 48109, USA.,Internal Medicine, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Yatrik M Shah
- Department of Molecular & Integrative Physiology, University of Michigan, Michigan, MI, 48109, USA. .,Internal Medicine, University of Michigan, Ann Arbor, MI, 48109, USA.
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12
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Frieler RA, Chung Y, Ahlers CG, Gheordunescu G, Song J, Vigil TM, Shah YM, Mortensen RM. Genetic neutrophil deficiency ameliorates cerebral ischemia-reperfusion injury. Exp Neurol 2017; 298:104-111. [PMID: 28865993 DOI: 10.1016/j.expneurol.2017.08.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [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: 01/27/2017] [Revised: 07/18/2017] [Accepted: 08/28/2017] [Indexed: 11/29/2022]
Abstract
Neutrophils respond rapidly to cerebral ischemia and are thought to contribute to inflammation-mediated injury during stroke. Using myeloid Mcl1 knockout mice as a model of genetic neutrophil deficiency, we investigated the contribution of neutrophils to stroke pathophysiology. Myeloid Mcl1 knockout mice were subjected to transient middle cerebral artery occlusion and infarct size was assessed by MRI after 24h reperfusion. Immune cell mobilization and infiltration was assessed by flow cytometry. We found that myeloid Mcl1 knockout mice had significantly reduced infarct size when compared to heterozygous and wild type control mice (MyMcl1+/+: 78.0mm3; MyMcl1+/-: 83.4mm3; MyMcl1-/-: 55.1mm3). This was accompanied by a nearly complete absence of neutrophils in the ischemic hemisphere of myeloid Mcl1 knockout mice. Although myeloid Mcl1 knockout mice were protected from cerebral infarction, no significant differences in neurological deficit or the mRNA expression of inflammatory genes (TNFα, IL-1β, and MCP1) were detected. Inhibition of neutrophil chemotaxis using CXCR2 pepducin treatment partially reduced neutrophil mobilization and recruitment to the brain after stroke, but did not reduce infarct size 24h after transient MCA occlusion. These data confirm that neutrophils have an important role in infarct development during stroke pathophysiology, and suggest that complete deficiency, but not partial inhibition, is necessary to prevent neutrophil-mediated injury during stroke.
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Affiliation(s)
- Ryan A Frieler
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, United States.
| | - Yutein Chung
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, United States.
| | - Carolyn G Ahlers
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, United States.
| | - George Gheordunescu
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, United States.
| | - Jianrui Song
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, United States.
| | - Thomas M Vigil
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, United States.
| | - Yatrik M Shah
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, United States.
| | - Richard M Mortensen
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, United States; Department of Internal Medicine, Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor, MI 48109, United States; Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, United States.
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13
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Frieler RA, Chung Y, Song J, Vigil TM, Mortensen RM. Abstract 496: Genetic Neutrophil Deficiency Ameliorates Cerebral Ischemia-Reperfusion Injury. Arterioscler Thromb Vasc Biol 2017. [DOI: 10.1161/atvb.37.suppl_1.496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background:
Neutrophils respond rapidly to cerebral ischemia and are thought to contribute to inflammation-mediated injury during stroke. Neutralizing antibodies and inhibition of neutrophil chemotactic molecules can be protective during models of stroke, but many of these techniques have the potential to result in cross-reactivity and non-specificity with other immune cell types. Using myeloid Mcl1 knockout mice as a model of genetic neutrophil deficiency, we investigated the contribution of neutrophils to stroke pathophysiology.
Methods:
Myeloid Mcl1 knockout mice were subjected to transient 90-min middle cerebral artery occlusion and infarct size was assessed by MRI after 24 hours reperfusion. Immune cell mobilization and infiltration was assessed by flow cytometry after 24 hours reperfusion.
Results:
We found that myeloid Mcl1 knockout mice had significantly reduced infarct size when compared to heterozygous and wild type control mice (MyMcl1
+/+
: 78.0 mm
3
; MyMcl1
+/-
: 83.4 mm
3
; MyMcl1
-/-
: 55.1 mm
3
). This was accompanied by a nearly complete absence of neutrophils in the ischemic hemisphere of myeloid Mcl1 knockout mice. Although myeloid Mcl1 knockout mice were protected from cerebral infarction, no significant differences in the expression of inflammatory genes were detected. Inhibition of neutrophil chemotaxis using CXCR2 pepducin treatment partially reduced neutrophil mobilization and recruitment to the brain after stroke, but did not reduce infarct size 24 hours after transient MCA occlusion.
Conclusions:
These data confirm that neutrophils have an important role in infarct development during stroke pathophysiology and suggest that complete deficiency, but not partial inhibition, is necessary to prevent neutrophil-mediated injury during stroke.
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14
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O’Donnell PE, Ye XZ, DeChellis MA, Davis VM, Duan SZ, Mortensen RM, Milstone DS. Lipodystrophy, Diabetes and Normal Serum Insulin in PPARγ-Deficient Neonatal Mice. PLoS One 2016; 11:e0160636. [PMID: 27505464 PMCID: PMC4978460 DOI: 10.1371/journal.pone.0160636] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 07/23/2016] [Indexed: 11/19/2022] Open
Abstract
Peroxisome proliferator activated receptor gamma (PPARγ) is a pleiotropic ligand activated transcription factor that acts in several tissues to regulate adipocyte differentiation, lipid metabolism, insulin sensitivity and glucose homeostasis. PPARγ also regulates cardiomyocyte homeostasis and by virtue of its obligate role in placental development is required for embryonic survival. To determine the postnatal functions of PPARγ in vivo we studied globally deficient neonatal mice produced by epiblast-restricted elimination of PPARγ. PPARγ-rescued placentas support development of PPARγ-deficient embryos that are viable and born in near normal numbers. However, PPARγ-deficient neonatal mice show severe lipodystrophy, lipemia, hepatic steatosis with focal hepatitis, relative insulin deficiency and diabetes beginning soon after birth and culminating in failure to thrive and neonatal lethality between 4 and 10 days of age. These abnormalities are not observed with selective PPARγ2 deficiency or with deficiency restricted to hepatocytes, skeletal muscle, adipocytes, cardiomyocytes, endothelium or pancreatic beta cells. These observations suggest important but previously unappreciated functions for PPARγ1 in the neonatal period either alone or in combination with PPARγ2 in lipid metabolism, glucose homeostasis and insulin sensitivity.
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Affiliation(s)
- Peter E. O’Donnell
- Vascular Research Division, Department of Pathology, Brigham & Women’s Hospital and Harvard Medical School, Boston, MA, United States of America
| | - Xiu Zhen Ye
- Vascular Research Division, Department of Pathology, Brigham & Women’s Hospital and Harvard Medical School, Boston, MA, United States of America
| | - Melissa A. DeChellis
- Vascular Research Division, Department of Pathology, Brigham & Women’s Hospital and Harvard Medical School, Boston, MA, United States of America
| | - Vannessa M. Davis
- Vascular Research Division, Department of Pathology, Brigham & Women’s Hospital and Harvard Medical School, Boston, MA, United States of America
| | - Sheng Zhong Duan
- Department of Physiology, University of Michigan Medical School, Ann Arbor, MI, United States of America
| | - Richard M. Mortensen
- Department of Physiology, University of Michigan Medical School, Ann Arbor, MI, United States of America
| | - David S. Milstone
- Vascular Research Division, Department of Pathology, Brigham & Women’s Hospital and Harvard Medical School, Boston, MA, United States of America
- * E-mail:
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15
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Manrique C, Sowers J, Aroor A, Jia G, Habibi J, Mortensen RM, Lastra G. Abstract 136: Mineralocorticoid Receptor Activation In Macrophages Mediates High Fat/high Sucrose Induced Vascular Stiffness in Female Mice. Hypertension 2015. [DOI: 10.1161/hyp.66.suppl_1.136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Enhanced mineralocorticoid receptor (MR) activation promotes vascular dysfunction and remodeling. We studied the role of MR activation in perivascular adipose tissue (PVAT) macrophages in the development of high-fat/high-fructose diet (“Western Diet”, WD) induced vascular stiffness in female mice.
Myeloid MR KO mice (MyMRKO) were fed a WD for 8 weeks (n=3). MyMRKO female mice (n=2) were infused with aldosterone (Aldo) for 3 weeks. Aortic stiffness was assessed in vivo by pulse wave velocity and ex vivo by atomic force microscopy. Vascular reactivity was studied in aortic rings.
MyMRKO mice were protected from Aldo and WD induced aortic stiffness and had greater endothelial-dependent and independent vasodilation compared to littermates (Fig. 1, 2).
Immunohistochemistry suggested decreased peri-aortic fibrosis and macrophage infiltration in Aldo infused MyMRKO (Fig.1).
We conclude that MR KO in myeloid cells protects against WD and Aldo-induced vascular stiffness in female mice. Our data support a role for MR activation in PVAT macrophages in the pathogenesis of WD-induced vascular dysfunction.
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16
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Frieler RA, Nadimpalli S, Boland LK, Xie A, Kooistra LJ, Song J, Chung Y, Cho KW, Lumeng CN, Wang MM, Mortensen RM. Depletion of macrophages in CD11b diphtheria toxin receptor mice induces brain inflammation and enhances inflammatory signaling during traumatic brain injury. Brain Res 2015. [PMID: 26208897 DOI: 10.1016/j.brainres.2015.07.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Immune cells have important roles during disease and are known to contribute to secondary, inflammation-induced injury after traumatic brain injury. To delineate the functional role of macrophages during traumatic brain injury, we depleted macrophages using transgenic CD11b-DTR mice and subjected them to controlled cortical impact. We found that macrophage depletion had no effect on lesion size assessed by T2-weighted MRI scans 28 days after injury. Macrophage depletion resulted in a robust increase in proinflammatory gene expression in both the ipsilateral and contralateral hemispheres after controlled cortical impact. Interestingly, this sizeable increase in inflammation did not affect lesion development. We also showed that macrophage depletion resulted in increased proinflammatory gene expression in the brain and kidney in the absence of injury. These data demonstrate that depletion of macrophages in CD11b-DTR mice can significantly modulate the inflammatory response during brain injury without affecting lesion formation. These data also reveal a potentially confounding inflammatory effect in CD11b-DTR mice that must be considered when interpreting the effects of macrophage depletion in disease models.
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Affiliation(s)
- Ryan A Frieler
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, 1137 E. Catherine St., 7708 Medical Science II, Ann Arbor, MI 48109, USA; Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Sameera Nadimpalli
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, 1137 E. Catherine St., 7708 Medical Science II, Ann Arbor, MI 48109, USA
| | - Lauren K Boland
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, 1137 E. Catherine St., 7708 Medical Science II, Ann Arbor, MI 48109, USA
| | - Angela Xie
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, 1137 E. Catherine St., 7708 Medical Science II, Ann Arbor, MI 48109, USA
| | - Laura J Kooistra
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, 1137 E. Catherine St., 7708 Medical Science II, Ann Arbor, MI 48109, USA
| | - Jianrui Song
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, 1137 E. Catherine St., 7708 Medical Science II, Ann Arbor, MI 48109, USA
| | - Yutein Chung
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, 1137 E. Catherine St., 7708 Medical Science II, Ann Arbor, MI 48109, USA
| | - Kae W Cho
- Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Carey N Lumeng
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, 1137 E. Catherine St., 7708 Medical Science II, Ann Arbor, MI 48109, USA; Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Michael M Wang
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, 1137 E. Catherine St., 7708 Medical Science II, Ann Arbor, MI 48109, USA; Department of Neurology, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Department of Neurology, Veterans Administration Ann Arbor Healthcare System, Ann Arbor, MI 48105, USA
| | - Richard M Mortensen
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, 1137 E. Catherine St., 7708 Medical Science II, Ann Arbor, MI 48109, USA; Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Department of Internal Medicine, Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
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Affiliation(s)
- Ryan A Frieler
- From Department of Molecular and Integrative Physiology (R.A.F., R.M.M.), Department of Internal Medicine, Metabolism, Endocrinology, and Diabetes Division (R.M.M.), and Department of Pharmacology (R.M.M.), University of Michigan Medical School, Ann Arbor
| | - Richard M Mortensen
- From Department of Molecular and Integrative Physiology (R.A.F., R.M.M.), Department of Internal Medicine, Metabolism, Endocrinology, and Diabetes Division (R.M.M.), and Department of Pharmacology (R.M.M.), University of Michigan Medical School, Ann Arbor.
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18
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He H, Tao H, Xiong H, Duan SZ, McGowan FX, Mortensen RM, Balschi JA. Rosiglitazone causes cardiotoxicity via peroxisome proliferator-activated receptor γ-independent mitochondrial oxidative stress in mouse hearts. Toxicol Sci 2014; 138:468-81. [PMID: 24449420 DOI: 10.1093/toxsci/kfu015] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
This study aims to test the hypothesis that thiazolidinedione rosiglitazone (RSG), a selective peroxisome proliferator-activated receptor γ (PPARγ) agonist, causes cardiotoxicity independently of PPARγ. Energy metabolism and mitochondrial function were measured in perfused hearts isolated from C57BL/6, cardiomyocyte-specific PPARγ-deficient mice, and their littermates. Cardiac function and mitochondrial oxidative stress were measured in both in vitro and in vivo settings. Treatment of isolated hearts with RSG at the supratherapeutic concentrations of 10 and 30 μM caused myocardial energy deficiency as evidenced by the decreases in [PCr], [ATP], ATP/ADP ratio, energy charge with a concomitant cardiac dysfunction as indicated by the decreases in left ventricular systolic pressure, rates of tension development and relaxation, and by an increase in end-diastolic pressure. When incubated with tissue homogenate or isolated mitochondria at these same concentrations, RSG caused mitochondrial dysfunction as evidenced by the decreases in respiration rate, substrate oxidation rates, and activities of complexes I and IV. RSG also increased complexes I- and III-dependent O₂⁻ production, decreased glutathione content, inhibited superoxide dismutase, and increased the levels of malondialdehyde, protein carbonyl, and 8-hydroxy-2-deoxyguanosine in mitochondria, consistent with oxidative stress. N-acetyl-L-cysteine (NAC) 20 mM prevented RSG-induced above toxicity at those in vitro settings. Cardiomyocyte-specific PPARγ deletion and PPARγ antagonist GW9662 did not prevent the observed cardiotoxicity. Intravenous injection of 10 mg/kg RSG also caused cardiac dysfunction and oxidative stress, 600 mg/kg NAC antagonized these adverse effects. In conclusion, this study demonstrates that RSG at supratherapeutic concentrations causes cardiotoxicity via a PPARγ-independent mechanism involving oxidative stress-induced mitochondrial dysfunction in mouse hearts.
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Affiliation(s)
- Huamei He
- Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
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Frieler RA, Ray JJ, Meng H, Ramnarayanan SP, Usher MG, Su EJ, Berger S, Pinsky DJ, Lawrence DA, Wang MM, Mortensen RM. Myeloid mineralocorticoid receptor during experimental ischemic stroke: effects of model and sex. J Am Heart Assoc 2012; 1:e002584. [PMID: 23316294 PMCID: PMC3541615 DOI: 10.1161/jaha.112.002584] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [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: 04/11/2012] [Accepted: 08/08/2012] [Indexed: 01/29/2023]
Abstract
BACKGROUND Mineralocorticoid receptor (MR) antagonists have protective effects in the brain during experimental ischemic stroke, and we have previously demonstrated a key role for myeloid MR during stroke pathogenesis. In this study, we explore both model- and sex-specific actions of myeloid MR during ischemic stroke. METHODS AND RESULTS The MR antagonist eplerenone significantly reduced the infarct size in male (control, 99.5 mm(3); eplerenone, 74.2 mm(3); n=8 to 12 per group) but not female (control, 84.0 mm(3); eplerenone, 83.7 mm(3); n=6 to 7 per group) mice after transient (90-minute) middle cerebral artery occlusion. In contrast to MR antagonism, genetic ablation of myeloid MR in female mice significantly reduced infarct size (myeloid MR knockout, 9.4 mm(3) [5.4 to 36.6]; control, 66.0 mm(3) [50.0 to 81.4]; n=6 per group) after transient middle cerebral artery occlusion. This was accompanied by reductions in inflammatory gene expression and improvement in neurological function. In contrast to ischemia-reperfusion, myeloid MR-knockout mice were not protected from permanent middle cerebral artery occlusion. The infarct size and inflammatory response after permanent occlusion showed no evidence of protection by myeloid MR knockout in photothrombotic and intraluminal filament models of permanent occlusion. CONCLUSIONS These studies demonstrate that MR antagonism is protective in male but not female mice during transient middle cerebral artery occlusion, whereas genetic ablation of myeloid MR is protective in both male and female mice. They also highlight important mechanistic differences in the role of myeloid cells in different models of stroke and confirm that specific myeloid phenotypes play key roles in stroke protection.
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Affiliation(s)
- Ryan A Frieler
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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Yang G, Jia Z, Aoyagi T, McClain D, Mortensen RM, Yang T. Systemic PPARγ deletion impairs circadian rhythms of behavior and metabolism. PLoS One 2012; 7:e38117. [PMID: 22899986 PMCID: PMC3416825 DOI: 10.1371/journal.pone.0038117] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Accepted: 05/01/2012] [Indexed: 11/19/2022] Open
Abstract
Compelling evidence from both human and animal studies suggests a physiological link between the circadian rhythm and metabolism but the underlying mechanism is still incompletely understood. We examined the role of PPARγ, a key regulator of energy metabolism, in the control of physiological and behavioral rhythms by analyzing two strains of whole-body PPARγ null mouse models. Systemic inactivation of PPARγ was generated constitutively by using Mox2-Cre mice (MoxCre/flox) or inducibly by using the tamoxifen system (EsrCre/flox/TM). Circadian variations in oxygen consumption, CO2 production, food and water intake, locomotor activity, and cardiovascular parameters were all remarkably suppressed in MoxCre/flox mice. A similar phenotype was observed in EsrCre/flox/TM mice, accompanied by impaired rhythmicity of the canonical clock genes in adipose tissues and liver but not skeletal muscles or the kidney. PPARγ inactivation in isolated preadipocytes following exposure to tamoxifen led to a similar blockade of the rhythmicity of the clock gene expression. Together, these results support an essential role of PPARγ in the coordinated control of circadian clocks and metabolic pathways.
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Affiliation(s)
- Guangrui Yang
- Department of Internal Medicine, University of Utah and Salt Lake Veterans Affairs Medical Center, Salt Lake City, Utah, United States of America
| | - Zhanjun Jia
- Department of Internal Medicine, University of Utah and Salt Lake Veterans Affairs Medical Center, Salt Lake City, Utah, United States of America
| | - Toshinori Aoyagi
- Department of Internal Medicine, University of Utah and Salt Lake Veterans Affairs Medical Center, Salt Lake City, Utah, United States of America
| | - Donald McClain
- Department of Internal Medicine, University of Utah and Salt Lake Veterans Affairs Medical Center, Salt Lake City, Utah, United States of America
| | - Richard M. Mortensen
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Tianxin Yang
- Department of Internal Medicine, University of Utah and Salt Lake Veterans Affairs Medical Center, Salt Lake City, Utah, United States of America
- Institute of Hypertension, Sun Yat-sen University School of Medicine, Guangzhou, China
- * E-mail:
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Shen Z, Li C, Frieler RA, Gerasimova AS, Lee SJ, Wu J, Wang MM, Lumeng CN, Brosius FC, Duan SZ, Mortensen RM. Smooth muscle protein 22 alpha-Cre is expressed in myeloid cells in mice. Biochem Biophys Res Commun 2012; 422:639-42. [PMID: 22609406 DOI: 10.1016/j.bbrc.2012.05.041] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 05/09/2012] [Indexed: 10/28/2022]
Abstract
BACKGROUND Experiments using Cre recombinase to study smooth muscle specific functions rely on strict specificity of Cre transgene expression. Therefore, accurate determination of Cre activity is critical to the interpretation of experiments using smooth muscle specific Cre. METHODS AND RESULTS Two lines of smooth muscle protein 22 α-Cre (SM22α-Cre) mice were bred to floxed mice in order to define Cre transgene expression. Southern blotting demonstrated that SM22α-Cre was expressed not only in tissues abundant of smooth muscle, but also in spleen, which consists largely of immune cells including myeloid and lymphoid cells. PCR detected SM22α-Cre expression in peripheral blood and peritoneal macrophages. Analysis of SM22α-Cre mice crossed with a recombination detector GFP mouse revealed GFP expression, and hence recombination, in circulating neutrophils and monocytes by flow cytometry. CONCLUSIONS SM22α-Cre mediates recombination not only in smooth muscle cells, but also in myeloid cells including neutrophils, monocytes, and macrophages. Given the known contributions of myeloid cells to cardiovascular phenotypes, caution should be taken when interpreting data using SM22α-Cre mice to investigate smooth muscle specific functions. Strategies such as bone marrow transplantation may be necessary when SM22α-Cre is used to differentiate the contribution of smooth muscle cells versus myeloid cells to observed phenotypes.
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Affiliation(s)
- Zhuxia Shen
- Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Clinical Research Center of Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
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Barbieri M, Di Filippo C, Esposito A, Marfella R, Rizzo MR, D'Amico M, Ferraraccio F, Di Ronza C, Duan SZ, Mortensen RM, Rossi F, Paolisso G. Effects of PPARs agonists on cardiac metabolism in littermate and cardiomyocyte-specific PPAR-γ-knockout (CM-PGKO) mice. PLoS One 2012; 7:e35999. [PMID: 22563432 PMCID: PMC3338561 DOI: 10.1371/journal.pone.0035999] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Accepted: 03/26/2012] [Indexed: 01/21/2023] Open
Abstract
Understanding the molecular regulatory mechanisms controlling for myocardial lipid metabolism is of critical importance for the development of new therapeutic strategies for heart diseases. The role of PPARγ and thiazolidinediones in regulation of myocardial lipid metabolism is controversial. The aim of our study was to assess the role of PPARγ on myocardial lipid metabolism and function and differentiate local/from systemic actions of PPARs agonists using cardiomyocyte-specific PPARγ -knockout (CM-PGKO) mice. To this aim, the effect of PPARγ, PPARγ/PPARα and PPARα agonists on cardiac function, intra-myocyte lipid accumulation and myocardial expression profile of genes and proteins, affecting lipid oxidation, uptake, synthesis, and storage (CD36, CPT1MIIA, AOX, FAS, SREBP1-c and ADPR) was evaluated in cardiomyocyte-specific PPARγ-knockout (CM-PGKO) and littermate control mice undergoing standard and high fat diet (HFD). At baseline, protein levels and mRNA expression of genes involved in lipid uptake, oxidation, synthesis, and accumulation of CM-PGKO mice were not significantly different from those of their littermate controls. At baseline, no difference in myocardial lipid content was found between CM-PGKO and littermate controls. In standard condition, pioglitazone and rosiglitazone do not affect myocardial metabolism while, fenofibrate treatment significantly increased CD36 and CPT1MIIA gene expression. In both CM-PGKO and control mice submitted to HFD, six weeks of treatment with rosiglitazone, fenofibrate and pioglitazone lowered myocardial lipid accumulation shifting myocardial substrate utilization towards greater contribution of glucose. In conclusion, at baseline, PPARγ does not play a crucial role in regulating cardiac metabolism in mice, probably due to its low myocardial expression. PPARs agonists, indirectly protect myocardium from lipotoxic damage likely reducing fatty acids delivery to the heart through the actions on adipose tissue. Nevertheless a direct non-PPARγ mediated mechanism of PPARγ agonist could not be ruled out.
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Affiliation(s)
- Michelangela Barbieri
- Department of Geriatric Medicine and Metabolic Diseases, Second University of Naples, Naples, Italy
| | - Clara Di Filippo
- Department of Experimental Medicine, Section of Pharmacology L. Donatelli, Second University of Naples, Naples, Italy
| | - Antonietta Esposito
- Department of Geriatric Medicine and Metabolic Diseases, Second University of Naples, Naples, Italy
| | - Raffaele Marfella
- Department of Geriatric Medicine and Metabolic Diseases, Second University of Naples, Naples, Italy
| | - Maria Rosaria Rizzo
- Department of Geriatric Medicine and Metabolic Diseases, Second University of Naples, Naples, Italy
| | - Michele D'Amico
- Department of Experimental Medicine, Section of Pharmacology L. Donatelli, Second University of Naples, Naples, Italy
| | - Franca Ferraraccio
- Department of Preventive Medicine, Second University of Naples, Naples, Italy
| | - Cristina Di Ronza
- Department of Experimental Medicine, Section of Pharmacology L. Donatelli, Second University of Naples, Naples, Italy
| | - Sheng Zhong Duan
- Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Richard M. Mortensen
- Metabolism, Endocrinology and Diabetes Division, Departments of Molecular and Integrative Physiology, Pharmacology, and Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Francesco Rossi
- Department of Experimental Medicine, Section of Pharmacology L. Donatelli, Second University of Naples, Naples, Italy
| | - Giuseppe Paolisso
- Department of Geriatric Medicine and Metabolic Diseases, Second University of Naples, Naples, Italy
- * E-mail:
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Frieler RA, Meng H, Duan SZ, Berger S, Schütz G, He Y, Xi G, Wang MM, Mortensen RM. Myeloid-specific deletion of the mineralocorticoid receptor reduces infarct volume and alters inflammation during cerebral ischemia. Stroke 2010; 42:179-85. [PMID: 21106954 DOI: 10.1161/strokeaha.110.598441] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND AND PURPOSE mineralocorticoid receptor (MR) antagonists have protective effects in rodent models of ischemic stroke, but the cell type-specific actions of these drugs are unknown. In the present study, we examined the contribution of myeloid cell MR during focal cerebral ischemia using myeloid-specific MR knockout mice. METHODS myeloid-specific MR knockout mice were subjected to transient (90 minutes) middle cerebral artery occlusion followed by 24 hours reperfusion (n=5 to 7 per group). Ischemic cerebral infarcts were identified by hematoxylin and eosin staining and quantified with image analysis software. Immunohistochemical localization of microglia and macrophages was performed using Iba1 staining, and the expression of inflammatory markers was measured after 24 hours of reperfusion by quantitative reverse transcription-polymerase chain reaction. RESULTS myeloid-specific MR knockout resulted in a 65% reduction in infarct volume (P=0.005) after middle cerebral artery occlusion. This was accompanied by a significant reduction in activated microglia and macrophages in the ischemic core. Furthermore, myeloid-specific MR knockout suppressed classically activated M1 macrophage markers tumor necrosis factor-α, interleukin-1β, monocyte chemoattractant protein-1, macrophage inflammatory protein-1α, and interleukin-6 at the same time as partially preserving the induction of alternatively activated, M2, markers Arg1, and Ym1. CONCLUSIONS these data demonstrate that myeloid MR activation exacerbates stroke and identify myeloid MR as a critical target for MR antagonists. Furthermore, these data indicate that MR activation has an important role in controlling immune cell function during the inflammatory response to stroke.
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Affiliation(s)
- Ryan A Frieler
- Department of Internal Medicine, Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Mich. 48109, USA
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Usher MG, Duan SZ, Ivaschenko CY, Frieler RA, Berger S, Schütz G, Lumeng CN, Mortensen RM. Myeloid mineralocorticoid receptor controls macrophage polarization and cardiovascular hypertrophy and remodeling in mice. J Clin Invest 2010; 120:3350-64. [PMID: 20697155 DOI: 10.1172/jci41080] [Citation(s) in RCA: 288] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Accepted: 06/30/2010] [Indexed: 12/12/2022] Open
Abstract
Inappropriate excess of the steroid hormone aldosterone, which is a mineralocorticoid receptor (MR) agonist, is associated with increased inflammation and risk of cardiovascular disease. MR antagonists are cardioprotective and antiinflammatory in vivo, and evidence suggests that they mediate these effects in part by aldosterone-independent mechanisms. Here we have shown that MR on myeloid cells is necessary for efficient classical macrophage activation by proinflammatory cytokines. Macrophages from mice lacking MR in myeloid cells (referred to herein as MyMRKO mice) exhibited a transcription profile of alternative activation. In vitro, MR deficiency synergized with inducers of alternatively activated macrophages (for example, IL-4 and agonists of PPARgamma and the glucocorticoid receptor) to enhance alternative activation. In vivo, MR deficiency in macrophages mimicked the effects of MR antagonists and protected against cardiac hypertrophy, fibrosis, and vascular damage caused by L-NAME/Ang II. Increased blood pressure and heart rates and decreased circadian variation were observed during treatment of MyMRKO mice with L-NAME/Ang II. We conclude that myeloid MR is an important control point in macrophage polarization and that the function of MR on myeloid cells likely represents a conserved ancestral MR function that is integrated in a transcriptional network with PPARgamma and glucocorticoid receptor. Furthermore, myeloid MR is critical for blood pressure control and for hypertrophic and fibrotic responses in the mouse heart and aorta.
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Affiliation(s)
- Michael G Usher
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan 48109-5622, USA
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Talbot JN, Jutkiewicz EM, Graves SM, Clemans CF, Nicol MR, Mortensen RM, Huang X, Neubig RR, Traynor JR. RGS inhibition at G(alpha)i2 selectively potentiates 5-HT1A-mediated antidepressant effects. Proc Natl Acad Sci U S A 2010; 107:11086-91. [PMID: 20534514 PMCID: PMC2890727 DOI: 10.1073/pnas.1000003107] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [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] [Indexed: 11/18/2022] Open
Abstract
Elevating serotonin (5-HT) levels with selective serotonin reuptake inhibitors (SSRIs) is the most widely used treatment for depression. However, current therapies are ineffective, have delayed benefit, or cause side effects in many patients. Here, we define a mechanism downstream of 5-HT1A receptors that mediates antidepressant-like behavior and is profoundly and selectively enhanced by genetic disruption of regulators of G protein signaling (RGS) activity at G(alpha)i2. Animals rendered insensitive to RGS protein regulation through a mutation in G(alpha)i2 (G184S) exhibited spontaneous antidepressant- and anxiolytic-like behaviors. Mice expressing RGS-insensitive G(alpha)i2 also exhibited increased cortical and hippocampal phosphorylation of glycogen synthase kinase-3beta, a constitutively active proapoptotic kinase that is inhibited through phosphorylation in response to serotonin, SSRIs, and 5-HT1 receptor agonists. Both behavioral and biochemical phenotypes were blocked by treatment with WAY 100635, a 5-HT1A-selective antagonist. RGS-insensitive mice were also 5-10 times more responsive to the antidepressant-like effects of the SSRI fluvoxamine and 5-HT1A-selective agonist 8-hydroxy-2-dipropylaminotetralin. In contrast, the antidepressant potency of agents acting through nonserotonergic mechanisms was unchanged as was 5-HT1A action on body temperature. The findings point to a critical role for endogenous RGS proteins to suppress the antidepressant-like effects of 5-HT1A receptor activation. By selectively enhancing the beneficial effects of serotonin, inhibition of RGS proteins represents a therapeutic approach for the treatment of mood disorders.
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MESH Headings
- Animals
- Antidepressive Agents/pharmacology
- Anxiety/drug therapy
- Anxiety/physiopathology
- Anxiety/psychology
- Behavior, Animal/drug effects
- Behavior, Animal/physiology
- GTP-Binding Protein alpha Subunit, Gi2/genetics
- GTP-Binding Protein alpha Subunit, Gi2/metabolism
- Gene Knock-In Techniques
- Humans
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Mutant Strains
- Mice, Transgenic
- Phenotype
- Piperazines/pharmacology
- Pyridines/pharmacology
- RGS Proteins/antagonists & inhibitors
- RGS Proteins/genetics
- Receptor, Serotonin, 5-HT1A/metabolism
- Selective Serotonin Reuptake Inhibitors/pharmacology
- Signal Transduction
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Affiliation(s)
- Jeffery N. Talbot
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109
- Department of Pharmaceutical and Biomedical Sciences, Raabe College of Pharmacy, Ohio Northern University, Ada, OH 45810; and
| | - Emily M. Jutkiewicz
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109
- Drug Abuse Research Center and
| | - Steven M. Graves
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109
| | - Crystal F. Clemans
- Department of Pharmaceutical and Biomedical Sciences, Raabe College of Pharmacy, Ohio Northern University, Ada, OH 45810; and
| | - Melanie R. Nicol
- Department of Pharmaceutical and Biomedical Sciences, Raabe College of Pharmacy, Ohio Northern University, Ada, OH 45810; and
| | | | - Xinyan Huang
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109
| | - Richard R. Neubig
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109
- Internal Medicine, University of Michigan, Ann Arbor, MI 48109
| | - John R. Traynor
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109
- Drug Abuse Research Center and
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Abstract
PURPOSE OF REVIEW Peroxisome proliferator-activated receptors (PPARs) are a family of nuclear receptors activated by nutrient molecules and their derivatives. Their role has been increasingly recognized to be important in hypertension, metabolic disorders and cardiovascular disease, including atherosclerosis. Control of innate inflammatory processes mostly through alteration of monocyte/macrophage phenotype promises to be a unifying paradigm in understanding the pleiotropic effects of PPAR agonists. RECENT FINDINGS Although PPAR-gamma was the first to be described as an anti-inflammatory agent, both PPAR-alpha and PPAR-delta are now known to have similar effects as well. Inflammation is an important part of the damage caused by hypertensive diseases. PPARs have now been recognized as important determinants of macrophage polarization. Monocyte precursors of classical and alternatively activated macrophages are being defined as important changes in progression of cardiovascular disease associated with metabolic syndrome including hypertension, hyperlipidemia and obesity. SUMMARY A major unifying role for PPARs in hypertension and its complications through modification of the innate immune system and inflammation is increasingly likely. PPAR agonists may be beneficial, alone or in combination with other drugs that modify the inflammatory response, in treating hypertension, atherosclerosis and metabolic derangements associated with obesity.
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Affiliation(s)
- Sheng Zhong Duan
- Nephrology Division, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan 48109-0622, USA
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Abstract
To determine the function of a gene in vitro, expression in heterologous cells is often employed. This can be done by transient expression, but often requires a more permanent expression of the gene and the creation of a cell line. This process can involve decisions as to the nature of construct used for expression, and invariably uses some strategy to select the transfected cells. Typically, these strategies use one of a number of genes that confer resistance to an added drug that will kill untransfected cells but not the transfected cells (positive selection). Alternatively, sometimes the strategy uses a gene that will confer sensitivity to a compound and kills the transfected cells (negative selection). This chapter discusses some of the strategies and genes used in creating cell line for in vitro study of gene function.
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Abstract
To determine the function of a gene in vitro, expression in heterologous cells is often employed. This can be done by transient expression, but often requires a more permanent expression of the gene and the creation of a cell line. This process can involve decisions as to the nature of construct used for expression, and invariably uses some strategy to select the transfected cells. Typically, these strategies use one of a number of genes that confer resistance to an added drug that will kill untransfected cells but not the transfected cells (positive selection). Alternatively, sometimes the strategy uses a gene that will confer sensitivity to a compound and kills the transfected cells (negative selection). This chapter discusses some of the strategies and genes used in creating cell line for in vitro study of gene function.
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Gupta D, Jetton TL, Mortensen RM, Duan SZ, Peshavaria M, Leahy JL. In vivo and in vitro studies of a functional peroxisome proliferator-activated receptor gamma response element in the mouse pdx-1 promoter. J Biol Chem 2008; 283:32462-70. [PMID: 18718916 PMCID: PMC2583321 DOI: 10.1074/jbc.m801813200] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2008] [Revised: 08/01/2008] [Indexed: 01/03/2023] Open
Abstract
We reported that peroxisome proliferator-activated receptor gamma (PPARgamma) transcriptionally regulates the beta-cell differentiation factor pancreatic duodenal homeobox (PDX)-1 based on in vitro RNA interference studies. We have now studied mice depleted of PPARgamma within the pancreas (PANC PPARgamma(-/-)) created by a Cre/loxP recombinase system, with Cre driven by the pdx-1 promoter. Male PANC PPARgamma(-/-) mice were hyperglycemic at 8 weeks of age (8.1+/-0.2 mM versus 6.4+/-0.3 mM, p=0.009) with islet cytoarchitecture and pancreatic mass of islet beta-cells that were indistinguishable from the controls. Islet PDX-1 mRNA (p=0.001) and protein levels (p=0.003) were lowered 60 and 40%, respectively, in tandem with impaired glucose-induced insulin secretion and loss of thiazolidinedione-induced increase in PDX-1 expression. We next identified a putative PPAR-response element (PPRE) in the mouse pdx-1 promoter with substantial homology to the corresponding region of the human PDX-1 promoter. Electrophoretic mobility supershift assays with nuclear extracts from beta-cell lines and mouse islets, also in vitro translated PPARgamma and retinoid X receptor, and chromatin immunoprecipitation analysis demonstrated specific binding of PPARgamma and retinoid X receptor to the human and mouse pdx-1 x PPREs. Transient transfection assays of beta-cells with reporter constructs of mutated PPREs showed dramatically reduced pdx-1 promoter activity. In summary, we have presented in vivo and in vitro evidence showing PPARgamma regulation of pdx-1 transcription in beta-cells, plus our results support an important regulatory role for PPARgamma in beta-cell physiology and thiazolidinedione pharmacology of type 2 diabetes.
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Affiliation(s)
- Dhananjay Gupta
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Vermont, Burlington, Vermont 05405, USA
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Abstract
Peroxisome proliferator-activated receptor (PPAR)-γ is a nuclear receptor and transcription factor in the steroid superfamily. PPAR-γ agonists, the thiazolidinediones, are clinically used to treat type 2 diabetes. In addition to its function in adipogenesis and increasing insulin sensitivity, PPAR-γ also plays critical roles in the vasculature. In vascular endothelial cells, PPAR-γ activation inhibits endothelial inflammation by suppressing inflammatory gene expression and therefore improves endothelial dysfunction. In vascular smooth muscle cells, PPAR-γ activation inhibits proliferation and migration and promotes apoptosis. In macrophages, PPAR-γ activation suppresses inflammation by regulating gene expression and increases cholesterol uptake and efflux. A recurring theme in many cell types is the modulation of the innate immunity system particularly through altering the activity of the nuclear factor κB. This system is likely to be even more prominent in modulating disease in vascular cells. The effects of PPAR-γ in the vascular cells translate into the beneficial function of this transcription factor in vascular disorders, including hypertension and atherosclerosis. Both human genetic studies and animal studies using transgenic mice have demonstrated the importance of PPAR-γ in these disorders. However, recent clinical studies have raised significant concerns about the cardiovascular side effects of thiazolidinediones, particularly rosiglitazone. Weighing the potential benefit and harm of PPAR-γ activation and exploring the functional mechanisms may provide a balanced view on the clinical use of these compounds and new approaches to the future therapeutics of vascular disorders associated with diabetes.
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Affiliation(s)
- Sheng Zhong Duan
- From the Departments of Molecular and Integrative Physiology (S.Z.D., M.G.U., R.M.M.), Pharmacology (R.M.M.), and Internal Medicine (R.M.M.), Metabolism Endocrinology and Diabetes Division, University of Michigan Medical School, Ann Arbor
| | - Michael G. Usher
- From the Departments of Molecular and Integrative Physiology (S.Z.D., M.G.U., R.M.M.), Pharmacology (R.M.M.), and Internal Medicine (R.M.M.), Metabolism Endocrinology and Diabetes Division, University of Michigan Medical School, Ann Arbor
| | - Richard M. Mortensen
- From the Departments of Molecular and Integrative Physiology (S.Z.D., M.G.U., R.M.M.), Pharmacology (R.M.M.), and Internal Medicine (R.M.M.), Metabolism Endocrinology and Diabetes Division, University of Michigan Medical School, Ann Arbor
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Ye CP, Duan SZ, Milstone DS, Mortensen RM. G(o) controls the hyperpolarization-activated current in embryonic stem cell-derived cardiocytes. Am J Physiol Heart Circ Physiol 2007; 294:H979-85. [PMID: 18156202 DOI: 10.1152/ajpheart.00293.2007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hyperpolarization current (I(f)) is an important player in controlling heart rate and is stimulated by cAMP and inhibited by members of the pertussis toxin-sensitive G-protein G(i)/G(o) family. We have successfully derived cardiocytes from embryonic stem cells lacking G(o) or G(i2) and G(i3). We have established that both basal and isoproterenol-stimulated activities of I(f) in these cardiocytes have typical nodal-atrial characteristics and are unaffected by targeted gene inactivation of the G proteins G(o) or G(i2) and G(i3). Under basal conditions, both G(o) and G(i) are required for muscarinic inhibition of I(f) activity via a mechanism that involves the generation of nitric oxide, whereas, with prior stimulation by beta-agonists, only G(o) is required and G(i) and nitric oxide production are not. Our findings establish an essential role for G(o) in the antiadrenergic effect of muscarinic agent on I(f).
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Affiliation(s)
- Chian P Ye
- Division of Endocrinology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA
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Abstract
Pressure overload (POL) is a classical model for studying cardiac hypertrophy, but there has been no direct measure of hemodynamics in a conscious ambulatory mouse model of POL. We used abdominal aortic constriction to produce POL and radiotelemetry to measure the blood pressure and heart rate for three weeks. The cardiac size correlated with the systolic pressure in the last week is better than other hemodynamic parameters. Cardiac fibrosis was more correlated to the cardiac size than to the systolic pressure. The expression of the cardiac genes that are typically associated with cardiac hypertrophy was correlated with both cardiac size and systolic pressure. In conclusion, the systolic pressure is the major determinant of cardiac hypertrophy in the murine POL model. In contrast, cardiac fibrosis shows the influence of other factors besides systolic pressure. The combination of the POL model with continuous direct measurements of hemodynamics represents a significant technological advance and will lead to an extended usefulness of POL methodologically.
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Affiliation(s)
- Sheng Zhong Duan
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, 7744 Med. Sci. II, 1150 W. Med. Ctr. Dr., Ann Arbor, MI 48109-0622, USA
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Ivashchenko CY, Duan SZ, Usher MG, Mortensen RM. PPAR-gamma knockout in pancreatic epithelial cells abolishes the inhibitory effect of rosiglitazone on caerulein-induced acute pancreatitis. Am J Physiol Gastrointest Liver Physiol 2007; 293:G319-26. [PMID: 17463185 DOI: 10.1152/ajpgi.00056.2007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [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] [Indexed: 01/31/2023]
Abstract
Peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonists, such as the thiazolidinediones (TZDs), decrease acute inflammation in both pancreatic cell lines and mouse models of acute pancreatitis. Since PPAR-gamma agonists have been shown to exert some of their actions independent of PPAR-gamma, the role of PPAR-gamma in pancreatic inflammation has not been directly tested. Furthermore, the differential role of PPAR-gamma in endodermal derivatives (acini, ductal cells, and islets) as opposed to the endothelial or inflammatory cells is unknown. To determine whether the effects of a TZD, rosiglitazone, on caerulein-induced acute pancreatitis are dependent on PPAR-gamma in the endodermal derivatives, we created a cell-type specific knock out of PPAR-gamma in pancreatic acini, ducts, and islets. PPAR-gamma knockout animals show a greater response in some inflammatory genes after caerulein challenge. The anti-inflammatory effect of rosiglitazone on edema, macrophage infiltration, and expression of the proinflammatory cytokines is significantly decreased in pancreata of the knockout animals compared with control animals. However, rosiglitazone retains its effect in the lungs of the pancreatic-specific PPAR-gamma knockout animals, likely due to direct anti-inflammatory effect on lung parenchyma. These data show that the PPAR-gamma in the pancreatic epithelia and islets is important in suppressing inflammation and is required for the anti-inflammatory effects of TZDs in acute pancreatitis.
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Affiliation(s)
- C Y Ivashchenko
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, 1150 W. Medical Center Drive, Ann Arbor, MI 48109, USA
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Duan SZ, Christe M, Milstone DS, Mortensen RM. Go but not Gi2 or Gi3 is required for muscarinic regulation of heart rate and heart rate variability in mice. Biochem Biophys Res Commun 2007; 357:139-43. [PMID: 17418106 PMCID: PMC1963439 DOI: 10.1016/j.bbrc.2007.03.130] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2007] [Accepted: 03/19/2007] [Indexed: 11/28/2022]
Abstract
Muscarinic receptor-mediated cardiac parasympathetic activity is essential for regulating heart rate and heart rate variability (HRV). It has not been clear which G(i)/G(o) protein is responsible for these effects. We addressed this question using knockout mice that lack G protein alpha(i2), alpha(i3), or alpha(o) specifically. Unlike previously reported, our alpha(o)-null mice had significantly more survivors with normal life span. Isolated hearts from alpha(o)-null mice demonstrated much less sensitivity to the negative chronotropic effects of the muscarinic agonist carbachol to lower heart rate at baseline and a more profound effect under the stimulation of the beta-adrenergic agonist isoproterenol. In the presence of parasympathetic activation indirectly produced by methoxamine, an alpha(1)-adrenergic agonist, alpha(o)-null mice showed markedly decreased HRV compared with wild-type control mice. These differences in heart rate and HRV were not observed in alpha(i2)-null or alpha(i3)-null mice. Our findings establish an essential role for alpha(o) G protein in the anti-adrenergic effect of carbachol on heart rate regulation.
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Affiliation(s)
- Sheng Zhong Duan
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Michael Christe
- Endocrine Division, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
| | - David S. Milstone
- Vascular Research Division, Department of Pathology, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
| | - Richard M. Mortensen
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan
- Departments of Pharmacology and Medicine, Metabolism Endocrine and Diabetes Division, University of Michigan Medical School, Ann Arbor, Michigan
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Duan SZ, Ivashchenko CY, Whitesall SE, D’Alecy LG, Duquaine DC, Brosius FC, Gonzalez FJ, Vinson C, Pierre MA, Milstone DS, Mortensen RM. Hypotension, lipodystrophy, and insulin resistance in generalized PPARgamma-deficient mice rescued from embryonic lethality. J Clin Invest 2007; 117:812-22. [PMID: 17304352 PMCID: PMC1794117 DOI: 10.1172/jci28859] [Citation(s) in RCA: 139] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2006] [Accepted: 12/19/2006] [Indexed: 01/27/2023] Open
Abstract
We rescued the embryonic lethality of global PPARgamma knockout by breeding Mox2-Cre (MORE) mice with floxed PPARgamma mice to inactivate PPARgamma in the embryo but not in trophoblasts and created a generalized PPARgamma knockout mouse model, MORE-PPARgamma knockout (MORE-PGKO) mice. PPARgamma inactivation caused severe lipodystrophy and insulin resistance; surprisingly, it also caused hypotension. Paradoxically, PPARgamma agonists had the same effect. We showed that another mouse model of lipodystrophy was hypertensive, ruling out the lipodystrophy as a cause. Further, high salt loading did not correct the hypotension in MORE-PGKO mice. In vitro studies showed that the vasculature from MORE-PGKO mice was more sensitive to endothelial-dependent relaxation caused by muscarinic stimulation, but was not associated with changes in eNOS expression or phosphorylation. In addition, vascular smooth muscle had impaired contraction in response to alpha-adrenergic agents. The renin-angiotensin-aldosterone system was mildly activated, consistent with increased vascular capacitance or decreased volume. These effects are likely mechanisms contributing to the hypotension. Our results demonstrated that PPARgamma is required to maintain normal adiposity and insulin sensitivity in adult mice. Surprisingly, genetic loss of PPARgamma function, like activation by agonists, lowered blood pressure, likely through a mechanism involving increased vascular relaxation.
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Affiliation(s)
- Sheng Zhong Duan
- Department of Molecular and Integrative Physiology and
Department of Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA.
Department of Surgery, William Beaumont Hospital, Royal Oak, Michigan, USA.
Department of Internal Medicine, Nephrology Division, University of Michigan Medical School, Ann Arbor, Michigan, USA.
Laboratory of Metabolism, National Cancer Institute, NIH, Bethesda, Maryland, USA.
Vascular Research Division, Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Department of Pharmacology and
Department of Internal Medicine, Metabolism, Endocrinology, and Diabetes Division, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Christine Y. Ivashchenko
- Department of Molecular and Integrative Physiology and
Department of Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA.
Department of Surgery, William Beaumont Hospital, Royal Oak, Michigan, USA.
Department of Internal Medicine, Nephrology Division, University of Michigan Medical School, Ann Arbor, Michigan, USA.
Laboratory of Metabolism, National Cancer Institute, NIH, Bethesda, Maryland, USA.
Vascular Research Division, Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Department of Pharmacology and
Department of Internal Medicine, Metabolism, Endocrinology, and Diabetes Division, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Steven E. Whitesall
- Department of Molecular and Integrative Physiology and
Department of Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA.
Department of Surgery, William Beaumont Hospital, Royal Oak, Michigan, USA.
Department of Internal Medicine, Nephrology Division, University of Michigan Medical School, Ann Arbor, Michigan, USA.
Laboratory of Metabolism, National Cancer Institute, NIH, Bethesda, Maryland, USA.
Vascular Research Division, Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Department of Pharmacology and
Department of Internal Medicine, Metabolism, Endocrinology, and Diabetes Division, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Louis G. D’Alecy
- Department of Molecular and Integrative Physiology and
Department of Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA.
Department of Surgery, William Beaumont Hospital, Royal Oak, Michigan, USA.
Department of Internal Medicine, Nephrology Division, University of Michigan Medical School, Ann Arbor, Michigan, USA.
Laboratory of Metabolism, National Cancer Institute, NIH, Bethesda, Maryland, USA.
Vascular Research Division, Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Department of Pharmacology and
Department of Internal Medicine, Metabolism, Endocrinology, and Diabetes Division, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Damon C. Duquaine
- Department of Molecular and Integrative Physiology and
Department of Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA.
Department of Surgery, William Beaumont Hospital, Royal Oak, Michigan, USA.
Department of Internal Medicine, Nephrology Division, University of Michigan Medical School, Ann Arbor, Michigan, USA.
Laboratory of Metabolism, National Cancer Institute, NIH, Bethesda, Maryland, USA.
Vascular Research Division, Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Department of Pharmacology and
Department of Internal Medicine, Metabolism, Endocrinology, and Diabetes Division, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Frank C. Brosius
- Department of Molecular and Integrative Physiology and
Department of Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA.
Department of Surgery, William Beaumont Hospital, Royal Oak, Michigan, USA.
Department of Internal Medicine, Nephrology Division, University of Michigan Medical School, Ann Arbor, Michigan, USA.
Laboratory of Metabolism, National Cancer Institute, NIH, Bethesda, Maryland, USA.
Vascular Research Division, Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Department of Pharmacology and
Department of Internal Medicine, Metabolism, Endocrinology, and Diabetes Division, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Frank J. Gonzalez
- Department of Molecular and Integrative Physiology and
Department of Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA.
Department of Surgery, William Beaumont Hospital, Royal Oak, Michigan, USA.
Department of Internal Medicine, Nephrology Division, University of Michigan Medical School, Ann Arbor, Michigan, USA.
Laboratory of Metabolism, National Cancer Institute, NIH, Bethesda, Maryland, USA.
Vascular Research Division, Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Department of Pharmacology and
Department of Internal Medicine, Metabolism, Endocrinology, and Diabetes Division, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Charles Vinson
- Department of Molecular and Integrative Physiology and
Department of Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA.
Department of Surgery, William Beaumont Hospital, Royal Oak, Michigan, USA.
Department of Internal Medicine, Nephrology Division, University of Michigan Medical School, Ann Arbor, Michigan, USA.
Laboratory of Metabolism, National Cancer Institute, NIH, Bethesda, Maryland, USA.
Vascular Research Division, Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Department of Pharmacology and
Department of Internal Medicine, Metabolism, Endocrinology, and Diabetes Division, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Melissa A. Pierre
- Department of Molecular and Integrative Physiology and
Department of Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA.
Department of Surgery, William Beaumont Hospital, Royal Oak, Michigan, USA.
Department of Internal Medicine, Nephrology Division, University of Michigan Medical School, Ann Arbor, Michigan, USA.
Laboratory of Metabolism, National Cancer Institute, NIH, Bethesda, Maryland, USA.
Vascular Research Division, Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Department of Pharmacology and
Department of Internal Medicine, Metabolism, Endocrinology, and Diabetes Division, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - David S. Milstone
- Department of Molecular and Integrative Physiology and
Department of Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA.
Department of Surgery, William Beaumont Hospital, Royal Oak, Michigan, USA.
Department of Internal Medicine, Nephrology Division, University of Michigan Medical School, Ann Arbor, Michigan, USA.
Laboratory of Metabolism, National Cancer Institute, NIH, Bethesda, Maryland, USA.
Vascular Research Division, Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Department of Pharmacology and
Department of Internal Medicine, Metabolism, Endocrinology, and Diabetes Division, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Richard M. Mortensen
- Department of Molecular and Integrative Physiology and
Department of Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA.
Department of Surgery, William Beaumont Hospital, Royal Oak, Michigan, USA.
Department of Internal Medicine, Nephrology Division, University of Michigan Medical School, Ann Arbor, Michigan, USA.
Laboratory of Metabolism, National Cancer Institute, NIH, Bethesda, Maryland, USA.
Vascular Research Division, Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Department of Pharmacology and
Department of Internal Medicine, Metabolism, Endocrinology, and Diabetes Division, University of Michigan Medical School, Ann Arbor, Michigan, USA
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Abstract
Cardiac automaticity is controlled by G protein-coupled receptors, such as adrenergic, muscarinic, and adenosine receptors. The strength and duration of G protein signaling is attenuated by regulator of G protein signaling (RGS) proteins acting as GTPase-activating proteins for Galpha subunits; however, little is known about the role of endogenous RGS proteins in cardiac function. We created point mutations in Galpha subunits that disrupt Galpha-RGS binding and introduced them into embryonic stem (ES) cells by homologous recombination. Spontaneously contacting cardiocytes derived from the ES cells were used to evaluate the role of endogenous RGS proteins in chronotropic regulation. The RGS-insensitive GalphaoG184S homozygous knock-in (GalphaoGS/GS) cells demonstrated enhanced adenosine A1 and muscarinic M2 receptor-mediated bradycardic responses. In contrast, Galphai2GS/GS cells showed enhanced responses to M2 but not A1 receptors. Similarly M2 but not A1 bradycardic responses were dramatically enhanced in Galphai2GS/GS mice. Blocking G protein-coupled inward rectifying K+ (GIRK) channels largely abolished the mutation-induced enhancement of the M2 receptor-mediated response but had a minimal effect on A1 responses. The Galphas-dependent stimulation of beating rate by the beta2 adrenergic receptor agonist procaterol was significantly attenuated in GalphaoGS/GS and nearly abolished in Galphai2GS/GS cells because of enhanced signaling via a pertussis toxin sensitive mechanism. Thus, endogenous RGS proteins potently reduce the actions of Galpha(i/o)-linked receptors on cardiac automaticity. Furthermore, M2 and A1 receptors differentially use Galphai2 and Galphao and associated downstream effectors. Thus, alterations in RGS function may play a role in pathophysiological processes and RGS proteins could represent novel cardiovascular therapeutic targets.
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Affiliation(s)
- Ying Fu
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA
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38
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Milstone DS, Pierre MA, Mana PM, O'Donnell PE, Davis VM, Cross JC, Mortensen RM, Stavrakis G. PPAR GAMMA IS EXPRESSED AND REGULATES PLACENTAL DEVELOPMENT AND TROPHOBLAST DIFFERENTIATION IN BOTH HUMANS AND MICE. FASEB J 2006. [DOI: 10.1096/fasebj.20.5.a1077-c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- David S Milstone
- PathologyBrigham & Women's HospitalHNRB 730G, 77 Avenue Louis PasteurBostonMA02115‐5817
| | - Melissa A Pierre
- PathologyBrigham & Women's HospitalHNRB 752, 77 Avenue Louis PasteurBostonMA02115‐5817
| | - Parast M Mana
- PathologyBrigham & Women's HospitalHNRB 752, 77 Avenue Louis PasteurBostonMA02115‐5817
| | - Peter E O'Donnell
- PathologyBrigham & Women's HospitalHNRB 752, 77 Avenue Louis PasteurBostonMA02115‐5817
| | - Vannessa M Davis
- PathologyBrigham & Women's HospitalHNRB 752, 77 Avenue Louis PasteurBostonMA02115‐5817
| | - James C Cross
- Department of Biochemistry & Molecular Biology
- Obstetrics & GynaecologyUniversity of CalgaryHSC Room 2279, 3330 Hospital Drive, N.W.CalgaryAlbertaT2N 4N1Canada
| | - Richard M Mortensen
- Molecular and Integrative PhysiologyUniversity of Michigan School of Medicine7726 Med. Sci. Bldg. IIAnn ArborMI48109‐0622
| | - George Stavrakis
- PathologyBrigham & Women's HospitalHNRB 752, 77 Avenue Louis PasteurBostonMA02115‐5817
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39
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Duan SZ, Ivashchenko CY, Russell MW, Milstone DS, Mortensen RM. Cardiomyocyte-specific knockout and agonist of peroxisome proliferator-activated receptor-gamma both induce cardiac hypertrophy in mice. Circ Res 2005; 97:372-9. [PMID: 16051889 DOI: 10.1161/01.res.0000179226.34112.6d] [Citation(s) in RCA: 203] [Impact Index Per Article: 10.7] [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] [Indexed: 11/16/2022]
Abstract
Peroxisome proliferator-activated receptor (PPAR)-gamma is required for adipogenesis but is also found in the cardiovascular system, where it has been proposed to oppose inflammatory pathways and act as a growth suppressor. PPAR-gamma agonists, thiazolidinediones (TZDs), inhibit cardiomyocyte growth in vitro and in pressure overload models. Paradoxically, TZDs also induce cardiac hypertrophy in animal models. To directly determine the role of cardiomyocyte PPAR-gamma, we have developed a cardiomyocyte-specific PPAR-gamma-knockout (CM-PGKO) mouse model. CM-PGKO mice developed cardiac hypertrophy with preserved systolic cardiac function. Treatment with a TZD, rosiglitazone, induced cardiac hypertrophy in both littermate control mice and CM-PGKO mice and activated distinctly different hypertrophic pathways from CM-PGKO. CM-PGKO mice were found to have increased expression of cardiac embryonic genes (atrial natriuretic peptide and beta-myosin heavy chain) and elevated nuclear factor kappaB activity in the heart, effects not found by rosiglitazone treatment. Rosiglitazone increased cardiac phosphorylation of p38 mitogen-activated protein kinase independent of PPAR-gamma, whereas rosiglitazone induced phosphorylation of extracellular signal-related kinase 1/2 in the heart dependent of PPAR-gamma. Phosphorylation of c-Jun N-terminal kinases was not affected by rosiglitazone or CM-PGKO. Surprisingly, despite hypertrophy, Akt phosphorylation was suppressed in CM-PGKO mouse heart. These data show that cardiomyocyte PPAR-gamma suppresses cardiac growth and embryonic gene expression and inhibits nuclear factor kappaB activity in vivo. Further, rosiglitazone causes cardiac hypertrophy at least partially independent of PPAR-gamma in cardiomyocytes and through different mechanisms from CM-PGKO.
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Affiliation(s)
- Sheng Zhong Duan
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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40
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Abstract
Regulator of G-protein signaling (RGS) proteins are very active GTPase-accelerating proteins (GAPs) in vitro and are expected to reduce signaling by G-protein coupled receptors in vivo. A novel method is presented to assess the in vivo role of RGS proteins in the function of a G protein in which Galpha subunits do not bind to RGS proteins or respond with enhanced GTPase activity. A point mutation in the switch I region of Galpha subunits (G184S Galpha(o) and G183S Galpha(i1)) blocks the interaction with RGS proteins but leaves intact the ability of Galpha to couple to betagamma subunits, receptors, and downstream effectors. Expression of the RGS-insensitive mutant G184S Galpha(o) in C6 glioma cells with the micro-opioid receptor dramatically enhances adenylylcyclase inhibition and activation of extracellular regulated kinase. Introducing the same G184S Galpha(o) protein into embryonic stem (ES) cells by gene targeting allows us to assess the functional importance of the endogenous RGS proteins using in vitro differentiation models and in intact mice. Using ES cell-derived cardiocytes, spontaneous and isoproterenol-stimulated beating rates were not different between wild-type and G184S Galpha(o) mutant cells; however, the bradycardiac response to adenosine A1 receptor agonists was enhanced significantly (seven-fold decrease EC50) in Galpha(o)RGSi mutant cells compared to wild-type Galpha(o), indicating a significant role of endogenous RGS proteins in cardiac automaticity regulation. The approach of using RGS-insensitive Galpha subunit knockins will reveal the role of RGS protein-mediated GAP activity in signaling by a given G(i/o) protein. This will reveal the full extent of RGS regulation and will not be confounded by redundancy in the function of multiple RGS proteins.
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Affiliation(s)
- Ying Fu
- Department of Pharmacology, University of Michigan, Ann Arbor 48105, USA
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Kosachunhanun N, Hunt SC, Hopkins PN, Williams RR, Jeunemaitre X, Corvol P, Ferri C, Mortensen RM, Hollenberg NK, Williams GH. Genetic determinants of nonmodulating hypertension. Hypertension 2003; 42:901-8. [PMID: 14530292 DOI: 10.1161/01.hyp.0000095615.83724.82] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We sought to determine whether genes of the renin-angiotensin-aldosterone system can predict the nonmodulating intermediate phenotype in essential hypertension. Aldosterone responses to angiotensin II were assessed in 298 subjects with hypertension. Subjects were genotyped at the angiotensinogen M235T, angiotensin-converting enzyme I/D, aldosterone synthase C-344 T, renin, angiotensin II type 1 receptor, and adducin loci. The data were analyzed by Student t test, ANOVA, stepwise linear regression and general linear model or GENMOD regression techniques, and chi2 analysis odds ratios (ORs). Aldosterone response varied by genotype for angiotensin and aldosterone synthase but not for the other loci. The combination of angiotensinogen 235 TT and angiotensin-converting enzyme DD showed further reduction (P=0.0377) when compared with angiotensinogen 235 TT alone, an example of genetic epistasis. When the subject was required also to possess the CYP11B2 -344 TT genotype, there was a further substantial reduction. Of these 3 loci, only angiotensinogen 235 TT significantly increased the OR of predicting the nonmodulating hypertensive phenotype (OR, 2.00; 95% confidence interval, 1.152 to 3.51). However, when angiotensin-converting enzyme DD was combined with angiotensinogen 235 TT, the OR nearly doubled to 3.74, with a further increase to 5.36-fold when the subject possessed all 3 genotypes. Thus, the angiotensinogen, angiotensin-converting enzyme, and aldosterone synthase genotypes identified individuals with the nonmodulating phenotype with an increasing degree of fidelity. For this subclass of essential hypertension, it is likely that genotyping can be substituted for complex phenotyping for therapeutic and preventive decision making.
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Affiliation(s)
- Natapong Kosachunhanun
- Endocrine-Hypertension Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Mass 02115, USA
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42
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Larson MK, Chen H, Kahn ML, Taylor AM, Fabre JE, Mortensen RM, Conley PB, Parise LV. Identification of P2Y12-dependent and -independent mechanisms of glycoprotein VI-mediated Rap1 activation in platelets. Blood 2003; 101:1409-15. [PMID: 12393417 DOI: 10.1182/blood-2002-05-1533] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Glycoprotein (GP) VI is a critical platelet collagen receptor, yet the steps involved in GPVI-mediated platelet activation remain incompletely understood. Because activation of Rap1, an abundant small guanosine triphosphatase (GTPase) in platelets, contributes to integrin alpha(IIb)beta(3) activation, we asked whether and how GPVI signaling activates Rap1 in platelets. Here we show that platelet Rap1 is robustly activated upon addition of convulxin, a GPVI-specific agonist. Using a reconstituted system in RBL-2H3 cells, we found that GPVI-mediated Rap1 activation is dependent on FcRgamma but independent of another platelet collagen receptor, alpha(2)beta(1). Interestingly, GPVI-mediated Rap1 activation in human platelets is largely dependent on adenosine diphosphate (ADP) signaling through the P2Y(12) and not the P2Y(1) receptor. However, experiments with specific ADP receptor antagonists and platelets from knockout mice deficient in P2Y(1) or the P2Y(12)-associated G-protein, Galphai(2), indicate that human and murine platelets also have a significant P2Y(12)-independent component of GPVI-mediated Rap1 activation. The P2Y(12)-independent component is dependent on phosphatidylinositol 3-kinase and is augmented by epinephrine-mediated signaling. P2Y(12)-dependent and -independent components are also observed in GPVI-mediated platelet aggregation, further supporting a role for Rap1 in aggregation. These results define mechanisms of GPVI-mediated platelet activation and implicate Rap1 as a key signaling protein in GPVI-induced platelet signaling.
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MESH Headings
- Adenosine Diphosphate/metabolism
- Animals
- Blood Platelets/enzymology
- Blood Platelets/physiology
- Crotalid Venoms/pharmacology
- Enzyme Activation/drug effects
- Epinephrine/physiology
- GTP-Binding Protein alpha Subunit, Gi2
- GTP-Binding Protein alpha Subunits, Gi-Go/blood
- GTP-Binding Protein alpha Subunits, Gi-Go/deficiency
- Humans
- Integrin alpha2beta1/blood
- Lectins, C-Type
- Membrane Proteins
- Mice
- Mice, Knockout
- Phosphatidylinositol 3-Kinases/blood
- Platelet Aggregation
- Platelet Membrane Glycoproteins/physiology
- Proto-Oncogene Proteins/blood
- Proto-Oncogene Proteins/deficiency
- Purinergic P2 Receptor Antagonists
- Receptors, IgG/blood
- Receptors, Purinergic P2/blood
- Receptors, Purinergic P2/deficiency
- Receptors, Purinergic P2/physiology
- Receptors, Purinergic P2Y1
- Receptors, Purinergic P2Y12
- Signal Transduction
- rap1 GTP-Binding Proteins/blood
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Affiliation(s)
- Mark K Larson
- Department of Pharmacology, Center for Thrombosis and Hemostasis and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, 27599, USA
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43
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Abstract
Pancreatic secretion can be influenced by cholecystokinin (CCK) either directly via actions on acinar cells or indirectly via actions on nerves. The presence and functional roles of CCK receptors on human pancreatic acinar cells remains unclear. In the current study human pancreatic acini were isolated and then treated with CCK-8, gastrin and/or carbachol. Functional parameters were measured including intracellular [Ca2+] and amylase secretion. It was observed that human acini did not respond to CCK agonists but did respond to carbachol with robust increases in functional parameters. Adenoviral-mediated gene transfer of CCK1 or CCK2 receptors to the human cells resulted in cell responses to CCK agonists. In order to determine the reason for the lack of responsiveness of the human acini, expression of receptor mRNAs was determined using quantitative RT-PCR and localized by in situ hybridization. mRNA levels for CCK1 receptors were approximately 30 times lower than those of CCK2 receptors, which were approximately 10 times lower than those of m3 Ach receptors as measured by quantitative PCR. Neither CCK1 nor CCK2 receptors were localized in adult human pancreas by in situ hybridization. These results indicate that human pancreatic acinar cells do not respond directly to CCK receptor activation and this is likely due to an insufficient level of receptor expression.
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Affiliation(s)
- Baoan Ji
- Department of Physiology, University of Michigan, Ann Arbor, MI 48109-0622, USA
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44
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Liao R, Jain M, Cui L, D'Agostino J, Aiello F, Luptak I, Ngoy S, Mortensen RM, Tian R. Cardiac-specific overexpression of GLUT1 prevents the development of heart failure attributable to pressure overload in mice. Circulation 2002; 106:2125-31. [PMID: 12379584 DOI: 10.1161/01.cir.0000034049.61181.f3] [Citation(s) in RCA: 241] [Impact Index Per Article: 11.0] [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] [Indexed: 11/16/2022]
Abstract
BACKGROUND Increased rates of glucose uptake and glycolysis have been repeatedly observed in cardiac hypertrophy and failure. Although these changes have been considered part of the fetal gene reactivation program, the functional significance of increased glucose utilization in hypertrophied and failing myocardium is poorly understood. METHODS AND RESULTS We generated transgenic (TG) mice with cardiac-specific overexpression of insulin-independent glucose transporter GLUT1 to recapitulate the increases in basal glucose uptake rate observed in hypertrophied hearts. Isolated perfused TG hearts showed a greater rate of basal glucose uptake and glycolysis than hearts isolated from wild-type littermates, which persisted after pressure overload by ascending aortic constriction (AAC). The in vivo cardiac function in TG mice, assessed by echocardiography, was unaltered. When subjected to AAC, wild-type mice exhibited a progressive decline in left ventricular (LV) fractional shortening accompanied by ventricular dilation and decreased phosphocreatine to ATP ratio and reached a mortality rate of 40% at 8 weeks. In contrast, TG-AAC mice maintained LV function and phosphocreatine to ATP ratio and had <10% mortality. CONCLUSIONS We found that increasing insulin-independent glucose uptake and glycolysis in adult hearts does not compromise cardiac function. Furthermore, we demonstrate that increasing glucose utilization in hypertrophied hearts protects against contractile dysfunction and LV dilation after chronic pressure overload.
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Affiliation(s)
- Ronglih Liao
- Cardiac Muscle Research Laboratory, Whitaker Cardiovascular Institute, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Mass 02115, USA
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Vernochet C, Milstone DS, Iehlé C, Belmonte N, Phillips B, Wdziekonski B, Villageois P, Amri EZ, O'Donnell PE, Mortensen RM, Ailhaud G, Dani C. PPARgamma-dependent and PPARgamma-independent effects on the development of adipose cells from embryonic stem cells. FEBS Lett 2002; 510:94-8. [PMID: 11755538 DOI: 10.1016/s0014-5793(01)03235-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Peroxisome proliferator-activated receptor (PPAR) gamma was shown to be required for adipocyte formation both in vivo and in vitro. However, the role of PPARgamma in the initial steps of adipose cell development was not distinguished from its role in the terminal steps. We now show that PPARgamma is expressed early in embryoid bodies (EBs) derived from embryonic stem cells and in E.8.5 mouse embryos. Addition of a specific ligand for PPARgamma in developing EBs over-expressing PPARgamma did not commit stem cells towards the adipose lineage. In differentiated PPARgamma(-/-) EBs, only markers characteristic of preadipocytes were found to be expressed. PPARdelta is present in EBs but did not compensate for the lack of PPARgamma in terminal differentiation. Taken together, these results favor a critical PPARgamma-independent phase culminating in preadipocyte formation that precedes a PPARgamma-dependent phase in the development of adipose cells from pluripotent stem cells.
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Affiliation(s)
- C Vernochet
- Institute of Signaling, Developmental Biology and Cancer Research, CNRS UMR 6543, Centre du Biochimie, 06108 Nice Cedex 2, France
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Abstract
BACKGROUND & AIMS Pancreatic acinar cells from various species express cholecystokinin (CCK) A, CCK-B, or a combination of these CCK receptor subtypes. The presence and functional roles of CCK receptors on human acinar cells remain unclear. METHODS Acini isolated from human pancreas were treated with CCK receptor agonists, CCK-8 and gastrin, and an agonist for m3 muscarinic acetylcholine receptors (m3 AchR), carbachol. Functional parameters measured included intracellular [Ca(2+)], amylase secretion, and ERK phosphorylation. Binding studies were performed using (125)I-CCK-8. Expression of messenger RNAs (mRNAs) was determined using real-time quantitative reverse-transcription polymerase chain reaction (RT-PCR) and localized by in situ hybridization. RESULTS Human acini did not respond to CCK agonists. In contrast, they responded to carbachol with robust increases in each of the functional parameters. Moreover, the cells responded to CCK agonists after adenoviral-mediated gene transfer of CCK-A or CCK-B receptors. A low level of specific and a high level of nonspecific binding of (125)I-CCK-8 were observed. Quantitative RT-PCR indicated that the message levels for CCK-A receptors were approximately 30-fold lower than those of CCK-B receptors, which were approximately 10-fold lower than those of m3 Ach receptors. In situ hybridization indicated the presence of m3 Ach receptor and insulin mRNA but not CCK-A or CCK-B receptor mRNAs in adult human pancreas. CONCLUSIONS These data indicate that human pancreatic acinar cells do not respond to CCK receptor agonists in terms of expected functional parameters and show that this is due to an insufficient level of receptor expression.
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Affiliation(s)
- B Ji
- Department of Physiology, University of Michigan, 7710 Medical Sciences Building II, Ann Arbor, MI 48109-0622, USA
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Svetkey LP, Moore TJ, Simons-Morton DG, Appel LJ, Bray GA, Sacks FM, Ard JD, Mortensen RM, Mitchell SR, Conlin PR, Kesari M. Angiotensinogen genotype and blood pressure response in the Dietary Approaches to Stop Hypertension (DASH) study. J Hypertens 2001; 19:1949-56. [PMID: 11677359 DOI: 10.1097/00004872-200111000-00004] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
OBJECTIVE To determine the relationship between angiotensinogen (ANG) genotype and blood pressure response to the dietary patterns of the Dietary Approaches to Stop Hypertension (DASH) trial. The angiotensin converting enzyme (ACE) gene was also tested. DESIGN The DASH trial was a randomized outpatient feeding study comparing the effects on blood pressure (BP) of three dietary patterns: a control diet, similar to typical American intake; a 'fruits and vegetables' diet (F/V) that is rich in fruits and vegetables but otherwise resembles the control diet; and the DASH diet that is reduced in fats and that emphasizes fruits, vegetables and low-fat dairy products. Participants' genotype was also determined. SETTING Four clinical sites. PARTICIPANTS Adults with above-optimal BP or stage 1 hypertension. INTERVENTION Participants ate one of the three dietary patterns for 8 weeks. Sodium intake and weight were held constant. In 355 of 459 DASH participants, DNA was extracted from leukocytes and genotyped for the G-6A ANG polymorphism and the D/I ACE polymorphism, by the polymerase chain reaction. MAIN OUTCOMES Genotype at ANG and ACE loci; BP after 8 weeks of intervention diet. RESULTS There was no association between ACE genotype and BP response. Associations with ANG polymorphism were significant: net systolic and diastolic BP response to the DASH diet was greatest in individuals with the AA genotype (-6.93/-3.68 mmHg) and least in those with the GG genotype (-2.80/0.20 mmHg). A similar relationship existed for the F/V diet. CONCLUSIONS ANG genotype is associated with BP response to the DASH diet. The AA genotype confers excess risk of hypertension and is associated with increased responsiveness to diet.
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Affiliation(s)
- L P Svetkey
- Duke Hypertension Center and Sarah W. Stedman Center for Nutritional Studies, Duke University Medical Center, Durham, North Carolina 27705, USA.
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Palakurthi SS, Aktas H, Grubissich LM, Mortensen RM, Halperin JA. Anticancer effects of thiazolidinediones are independent of peroxisome proliferator-activated receptor gamma and mediated by inhibition of translation initiation. Cancer Res 2001; 61:6213-8. [PMID: 11507074] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
The thiazolidinedione (TZD) class of peroxisome proliferator-activated receptor (PPAR) gamma ligands, known for their ability to induce adipocyte differentiation and increase insulin sensitivity, also exhibits anticancer properties. Currently, TZDs are being tested in clinical trials for treatment of human cancers expressing high levels of PPARgamma because it is assumed that activation of PPARgamma mediates their anticancer activity. Using PPARgamma(-/-) and PPARgamma(+/+) mouse embryonic stem cells, we report here that inhibition of cell proliferation and tumor growth by TZDs is independent of PPARgamma. Our studies demonstrate that these compounds block G(1)-S transition by inhibiting translation initiation. Inhibition of translation initiation is the consequence of partial depletion of intracellular calcium stores and the resulting activation of protein kinase R that phosphorylates the alpha subunit of eukaryotic initiation factor 2 (eIF2), thus rendering eIF2 inactive. PPARgamma-independent inhibition of translation initiation most likely accounts for the anticancer properties of thiazolidinediones.
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Affiliation(s)
- S S Palakurthi
- Laboratory for Membrane Transport, Harvard Medical School, Boston, Massachusetts 02115, USA
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Abstract
The intracellular signaling pathways by which G protein-coupled receptors on the platelet surface initiate aggregation, a critical process for hemostasis and thrombosis, are not well understood. In particular, the contribution of the G(i) pathway has not been directly addressed. We have investigated the activation of platelets from mice in which the gene for the predominant platelet G alpha(i) subtype, G alpha(i2), has been disrupted. In intact platelets from G alpha(i2)-deficient mice, the inhibition of adenylyl cyclase by ADP was found to be partially impaired compared with wild-type platelets. Moreover, both ADP-dependent platelet aggregation and the activation of the integrin alpha IIb beta 3 (GPIIb-IIIa) were strongly reduced in platelets from G alpha(i2)-deficient mice. In addition, G alpha(i2)-deficient platelets displayed impaired activation at low thrombin concentrations. This defect was mimicked by blocking the adenylyl cyclase--coupled platelet ADP receptor (P2Y(12)) on wild-type platelets with a selective antagonist. These observations suggest that G alpha(i2) is involved in the inhibition of platelet adenylyl cyclase in vivo and is a critical component of the signaling pathway for integrin activation by ADP, resulting in platelet aggregation. In addition, thrombin-dependent activation of mouse platelets is mediated, at least in part, by secreted ADP acting on the G alpha(i2)-linked ADP receptor.
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Affiliation(s)
- H M Jantzen
- COR Therapeutics Inc., South San Francisco, California 94080, USA.
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Jain M, Lim CC, Nagata K, Davis VM, Milstone DS, Liao R, Mortensen RM. Targeted inactivation of Galpha(i) does not alter cardiac function or beta-adrenergic sensitivity. Am J Physiol Heart Circ Physiol 2001; 280:H569-75. [PMID: 11158953 DOI: 10.1152/ajpheart.2001.280.2.h569] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [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] [Indexed: 11/22/2022]
Abstract
Inhibitory Galpha(i) protein increases in the myocardium during hypertrophy and has been associated with beta-adrenergic receptor (beta-AR) desensitization, contractile dysfunction, and progression of cardiac disease. The role of Galpha(i) proteins in mediating basal cardiac function and beta-AR response in nonpathological myocardium, however, is uncertain. Transgenic mice with targeted inactivation of Galpha(i2) or Galpha(i3) were examined for in vivo cardiac function with the use of conscious echocardiography and for ex vivo cardiac response to inotropic stimulation with the use of Langendorff blood-perfused isolated hearts and adult ventricular cardiomyocytes. Echocardiography revealed that percent fractional shortening and heart rate were similar among wild-type, Galpha(i2)-null, and Galpha(i3)-null mice. Comparable baseline diastolic and contractile performance was also observed in isolated hearts and isolated ventricular myocytes from wild-type mice and mice lacking Galpha(i) proteins. Isoproterenol infusion enhanced diastolic and contractile performance to a similar degree in wild-type, Galpha(i2)-null, and Galpha(i3)-null mice. These data demonstrate no observable role for inhibitory G proteins in mediating basal cardiac function or sensitivity to beta-AR stimulation in nonpathological myocardium.
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Affiliation(s)
- M Jain
- Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts 02115, USA
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