151
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Kim M, Platt MJ, Shibasaki T, Quaggin SE, Backx PH, Seino S, Simpson JA, Drucker DJ. GLP-1 receptor activation and Epac2 link atrial natriuretic peptide secretion to control of blood pressure. Nat Med 2013; 19:567-75. [PMID: 23542788 DOI: 10.1038/nm.3128] [Citation(s) in RCA: 366] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 02/12/2013] [Indexed: 12/15/2022]
Abstract
Glucagon-like peptide-1 receptor (GLP-1R) agonists exert antihypertensive actions through incompletely understood mechanisms. Here we demonstrate that cardiac Glp1r expression is localized to cardiac atria and that GLP-1R activation promotes the secretion of atrial natriuretic peptide (ANP) and a reduction of blood pressure. Consistent with an indirect ANP-dependent mechanism for the antihypertensive effects of GLP-1R activation, the GLP-1R agonist liraglutide did not directly increase the amount of cyclic GMP (cGMP) or relax preconstricted aortic rings; however, conditioned medium from liraglutide-treated hearts relaxed aortic rings in an endothelium-independent, GLP-1R-dependent manner. Liraglutide did not induce ANP secretion, vasorelaxation or lower blood pressure in Glp1r(-/-) or Nppa(-/-) mice. Cardiomyocyte GLP-1R activation promoted the translocation of the Rap guanine nucleotide exchange factor Epac2 (also known as Rapgef4) to the membrane, whereas Epac2 deficiency eliminated GLP-1R-dependent stimulation of ANP secretion. Plasma ANP concentrations were increased after refeeding in wild-type but not Glp1r(-/-) mice, and liraglutide increased urine sodium excretion in wild-type but not Nppa(-/-) mice. These findings define a gut-heart GLP-1R-dependent and ANP-dependent axis that regulates blood pressure.
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Affiliation(s)
- Minsuk Kim
- Department of Medicine, Samuel Lunenfeld Research Institute, Mt. Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
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152
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Kashima Y, Takahashi M, Shiba Y, Itano N, Izawa A, Koyama J, Nakayama J, Taniguchi S, Kimata K, Ikeda U. Crucial role of hyaluronan in neointimal formation after vascular injury. PLoS One 2013; 8:e58760. [PMID: 23484050 PMCID: PMC3590137 DOI: 10.1371/journal.pone.0058760] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 02/06/2013] [Indexed: 01/04/2023] Open
Abstract
Background Hyaluronan (HA) is a primary component of the extracellular matrix of cells, and it is involved in the pathogenesis of atherosclerosis. The purpose of this study was to investigate the role of HA in neointimal formation after vascular injury and determine its tissue-specific role in vascular smooth muscle cells (VSMCs) by using a cre-lox conditional transgenic (cTg) strategy. Methods and Results HA was found to be expressed in neointimal lesions in humans with atherosclerosis and after wire-mediated vascular injury in mice. Inhibition of HA synthesis using 4-methylumbelliferone markedly inhibited neointimal formation after injury. In vitro experiments revealed that low-molecular-weight HA (LMW-HA) induced VSMC activation, including migration, proliferation, and production of inflammatory cytokines, and reactive oxygen species (ROS). The migration and proliferation of VSMCs were mediated by the CD44/RhoA and CD44/ERK1/2 pathways, respectively. Because HA synthase 2 (HAS2) is predominantly expressed in injured arteries, we generated cTg mice that overexpress the murine HAS2 gene specifically in VSMCs (cHAS2/CreSM22α mice) and showed that HA overexpression markedly enhanced neointimal formation after cuff-mediated vascular injury. Further, HA-overexpressing VSMCs isolated from cHAS2/CreSM22α mice showed augmented migration, proliferation, and production of inflammatory cytokines and ROS. Conclusion VSMC-derived HA promotes neointimal formation after vascular injury, and HA may be a potential therapeutic target for cardiovascular disease.
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Affiliation(s)
- Yuichiro Kashima
- Department of Cardiovascular Medicine, Shinshu University Graduate School of Medicine, Matsumoto, Japan
| | - Masafumi Takahashi
- Department of Cardiovascular Medicine, Shinshu University Graduate School of Medicine, Matsumoto, Japan
- Division of Bioimaging Sciences, Center for Molecular Medicine, Jichi Medical University, Tochigi, Japan
- * E-mail:
| | - Yuji Shiba
- Department of Cardiovascular Medicine, Shinshu University Graduate School of Medicine, Matsumoto, Japan
| | - Naoki Itano
- Department of Molecular Biosciences, Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, Japan
| | - Atsushi Izawa
- Department of Cardiovascular Medicine, Shinshu University Graduate School of Medicine, Matsumoto, Japan
| | - Jun Koyama
- Department of Cardiovascular Medicine, Shinshu University Graduate School of Medicine, Matsumoto, Japan
| | - Jun Nakayama
- Department of Molecular Pathology, Shinshu University Graduate School of Medicine, Matsumoto, Japan
| | - Shun'ichiro Taniguchi
- Department of Molecular Oncology, Shinshu University Graduate School of Medicine, Matsumoto, Japan
| | - Koji Kimata
- Research Complex for the Medicine Frontiers, Aich Medical University, Aichi, Japan
| | - Uichi Ikeda
- Department of Cardiovascular Medicine, Shinshu University Graduate School of Medicine, Matsumoto, Japan
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153
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Systemic and local infection routes govern different cellular dissemination pathways during gammaherpesvirus infection in vivo. J Virol 2013; 87:4596-608. [PMID: 23408606 DOI: 10.1128/jvi.03135-12] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Human gammaherpesviruses cause morbidity and mortality associated with infection and transformation of lymphoid and endothelial cells. Knowledge of cell types involved in virus dissemination from primary virus entry to virus latency is fundamental for the understanding of gammaherpesvirus pathogenesis. However, the inability to directly trace cell types with respect to virus dissemination pathways has prevented definitive conclusions regarding the relative contribution of individual cell types. Here, we describe that the route of infection affects gammaherpesvirus dissemination pathways. We constructed a recombinant murine gammaherpesvirus 68 (MHV-68) variant harboring a cassette which switches fluorescent markers in a Cre-dependent manner. Since the recombinant virus which was constructed on the wild-type background was attenuated, in this study we used an M1-deleted version, which infected mice with normal kinetics. Infection of Cre-transgenic mice with this convertible virus was used to estimate the quantitative contribution of defined cell types to virus productivity and dissemination during the acute phase of MHV-68 infection. In systemic infection, we found splenic vascular endothelial cells (EC) among the first and main cells to produce virus. After local infection, the contribution of EC to splenic virus production did not represent such early kinetics. However, at later time points, B cell-derived viruses dominated splenic productivity independently of systemic or local infection. Systemic versus local infection also governed the cell types involved in loading peritoneal exudate cells, leading to latency in F4/80- and CD11b-positive target cells. Systemic infection supported EC-driven dissemination, whereas local infection supported B cell-driven dissemination.
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154
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LRP1 in brain vascular smooth muscle cells mediates local clearance of Alzheimer's amyloid-β. J Neurosci 2013; 32:16458-65. [PMID: 23152628 DOI: 10.1523/jneurosci.3987-12.2012] [Citation(s) in RCA: 162] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Impaired clearance of amyloid-β (Aβ) is a major pathogenic event for Alzheimer's disease (AD). Aβ depositions in brain parenchyma as senile plaques and along cerebrovasculature as cerebral amyloid angiopathy (CAA) are hallmarks of AD. A major pathway that mediates brain Aβ clearance is the cerebrovascular system where Aβ is eliminated through the blood-brain barrier (BBB) and/or degraded by cerebrovascular cells along the interstitial fluid drainage pathway. An Aβ clearance receptor, the low-density lipoprotein receptor-related protein 1 (LRP1), is abundantly expressed in cerebrovasculature, in particular in vascular smooth muscle cells. Previous studies have indicated a role of LRP1 in endothelial cells in transcytosing Aβ out of the brain across the BBB; however, whether this represents a significant pathway for brain Aβ clearance remains controversial. Here, we demonstrate that Aβ can be cleared locally in the cerebrovasculature by an LRP1-dependent endocytic pathway in smooth muscle cells. The uptake and degradation of both endogenous and exogenous Aβ were significantly reduced in LRP1-suppressed human brain vascular smooth muscle cells. Conditional deletion of Lrp1 in vascular smooth muscle cell in amyloid model APP/PS1 mice accelerated brain Aβ accumulation and exacerbated Aβ deposition as amyloid plaques and CAA without affecting Aβ production. Our results demonstrate that LRP1 is a major Aβ clearance receptor in cerebral vascular smooth muscle cell and a disturbance of this pathway contributes to Aβ accumulation. These studies establish critical functions of the cerebrovasculature system in Aβ metabolism and identify a new pathway involved in the pathogenesis of both AD and CAA.
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155
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Huang Z, Rivas B, Agoulnik AI. Insulin-like 3 signaling is important for testicular descent but dispensable for spermatogenesis and germ cell survival in adult mice. Biol Reprod 2012; 87:143. [PMID: 23100620 DOI: 10.1095/biolreprod.112.103382] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Relaxin family peptide receptor 2 (RXFP2) is the cognate receptor of a peptide hormone insulin-like 3 (INSL3). INSL3 is expressed at high levels in both fetal and adult Leydig cells. Deletion of Insl3 or Rxfp2 genes in mice caused cryptorchidism resulting from a failure of gubernaculum development. Using a novel mouse transgenic line with a knock-in LacZ reporter in the Rxfp2 locus, we detected a robust Rxfp2 expression in embryonic and early postnatal gubernaculum in males and in postmeiotic spermatogenic cells in adult testis. To study the role of INSL3/RXFP2 signaling in male reproduction, we produced a floxed Rxfp2 allele and used the Cre/loxP approach to delete Rxfp2 in different tissues. Using Cre transgene driven by retinoic acid receptor beta promoter, conditional gene targeting in gubernacular mesenchymal cells at early embryonic stages caused high intraabdominal cryptorchidism as in males with a global deletion of Rxfp2. However, when the Rxfp2 was deleted in gubernacular smooth or striated muscle cells, no abnormalities of testicular descent or testis development were found. Specific ablation of Rxfp2 in male germ cells using Stra8-icre transgene did not affect testis descent, spermatogenesis, or fertility in adult males. No significant change in germ cell apoptosis was detected in mutant males. In summary, our data indicate that the INSL3/RXFP2 signaling is important for testicular descent but dispensable for spermatogenesis and fertility in adult males.
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Affiliation(s)
- Zaohua Huang
- Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida 33199, USA
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156
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Schreier B, Rabe S, Schneider B, Bretschneider M, Rupp S, Ruhs S, Neumann J, Rueckschloss U, Sibilia M, Gotthardt M, Grossmann C, Gekle M. Loss of epidermal growth factor receptor in vascular smooth muscle cells and cardiomyocytes causes arterial hypotension and cardiac hypertrophy. Hypertension 2012; 61:333-40. [PMID: 23248150 DOI: 10.1161/hypertensionaha.112.196543] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The epidermal growth factor receptor (EGFR), a receptor tyrosine kinase, contributes to parainflammatory dysregulation, possibly causing cardiovascular dysfunction and remodeling. The physiological role of cardiovascular EGFR is not completely understood. To investigate the physiological importance of EGFR in vascular smooth muscle cells and cardiomyocytes, we generated a mouse model with targeted deletion of the EGFR using the SM22 (smooth muscle-specific protein 22) promoter. While the reproduction of knockout animals was not impaired, life span was significantly reduced. Systolic blood pressure was not different between the 2 genotypes-neither in tail cuff nor in intravascular measurements-whereas total peripheral vascular resistance, diastolic blood pressure, and mean blood pressure were reduced. Loss of vascular smooth muscle cell-EGFR results in a dilated vascular phenotype with minor signs of fibrosis and inflammation. Echocardiography, necropsy, and histology revealed a dramatic eccentric cardiac hypertrophy in knockout mice (2.5-fold increase in heart weight), with increased stroke volume and cardiac output as well as left ventricular wall thickness and lumen. Cardiac hypertrophy is accompanied by an increase in cardiomyocyte volume, a strong tendency to cardiac fibrosis and inflammation, as well as enhanced NADPH-oxidase 4 and hypertrophy marker expression. Thus, in cardiomyocytes, EGFR prevents excessive hypertrophic growth through its impact on reactive oxygen species balance, whereas in vascular smooth muscle cells EGFR contributes to the appropriate vascular wall architecture and vessel reactivity, thereby supporting a physiological vascular tone.
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Affiliation(s)
- Barbara Schreier
- Julius-Bernstein-Institute of Physiology, Medical Faculty, University of Halle-Wittenberg, Halle, Germany.
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157
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Vitkus S, Yeh CR, Lin HH, Hsu I, Yu J, Chen M, Yeh S. Distinct function of estrogen receptor α in smooth muscle and fibroblast cells in prostate development. Mol Endocrinol 2012. [PMID: 23204329 DOI: 10.1210/me.2012-1212] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Estrogen signaling, through estrogen receptor (ER)α, has been shown to cause hypertrophy in the prostate. Our recent report has shown that epithelial ERα knockout (KO) will not affect the normal prostate development or homeostasis. However, it remains unclear whether ERα in different types of stromal cells has distinct roles in prostate development. This study proposed to elucidate how KO of ERα in the stromal smooth muscle or fibroblast cells may interrupt cross talk between prostate stromal and epithelial cells. Smooth muscle ERαKO (smERαKO) mice showed decreased glandular infolding with the proximal area exhibiting a significant decrease. Fibroblast ERαKO mouse prostates did not exhibit this phenotype but showed a decrease in the number of ductal tips. Additionally, the amount of collagen observed in the basement membrane was reduced in smERαKO prostates. Interestingly, these phenotypes were found to be mutually exclusive among smERαKO or fibroblast ERαKO mice. Compound KO of ERα in both fibroblast and smooth muscle showed combined phenotypes from each of the single KO. Further mechanistic studies showed that IGF-I and epidermal growth factor were down-regulated in prostate smooth muscle PS-1 cells lacking ERα. Together, our results indicate the distinct functions of fibroblast vs. smERα in prostate development.
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Affiliation(s)
- Spencer Vitkus
- Departments of Urology and Pathology, University of Rochester Medical Center, Rochester, New York 14642, USA
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158
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Davis J, Maillet M, Miano JM, Molkentin JD. Lost in transgenesis: a user's guide for genetically manipulating the mouse in cardiac research. Circ Res 2012; 111:761-77. [PMID: 22935533 DOI: 10.1161/circresaha.111.262717] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The advent of modern mouse genetics has benefited many fields of diseased-based research over the past 20 years, none perhaps more profoundly than cardiac biology. Indeed, the heart is now arguably one of the easiest tissues to genetically manipulate, given the availability of an ever-growing tool chest of molecular reagents/promoters and "facilitator" mouse lines. It is now possible to modify the expression of essentially any gene or partial gene product in the mouse heart at any time, either gain or loss of function. This review is designed as a handbook for the nonmouse geneticist and/or junior investigator to permit the successful manipulation of any gene or RNA product in the heart, while avoiding artifacts. In the present review, guidelines, pitfalls, and limitations are presented so that rigorous and appropriate examination of cardiac genotype-phenotype relationships can be performed. This review uses examples from the field to illustrate the vast spectrum of experimental and design details that must be considered when using genetically modified mouse models to study cardiac biology.
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Affiliation(s)
- Jennifer Davis
- Department of Pediatrics, University of Cincinnati, Howard Hughes Medical Institute, Cincinnati Children's Hospital Medical Center, 240 Albert Sabin Way, S4.409, Cincinnati, OH 45229, USA
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159
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Klinger JR, Tsai SW, Green S, Grinnell KL, Machan JT, Harrington EO. Atrial natriuretic peptide attenuates agonist-induced pulmonary edema in mice with targeted disruption of the gene for natriuretic peptide receptor-A. J Appl Physiol (1985) 2012. [PMID: 23195629 DOI: 10.1152/japplphysiol.01249.2011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Atrial natriuretic peptide (ANP) inhibits agonist-induced pulmonary edema formation, but the signaling pathway responsible is not well defined. To investigate the role of the particulate guanylate cyclase-linked receptor, natriuretic peptide receptor-A (NPR-A), we measured acute lung injury responses in intact mice and pulmonary microvascular endothelial cells (PMVEC) with normal and disrupted expression of NPR-A. NPR-A wild-type (NPR-A+/+), heterozygous (NPR-A+/-), and knockout (NPR-A-/-) mice were anesthetized and treated with thrombin receptor agonist peptide (TRAP) or lipopolysaccharide (LPS). Lung injury was assessed by lung wet-to-dry (W/D) weight and by protein and cell concentration of bronchoalveolar lavage (BAL) fluid. No difference in pulmonary edema formation was seen between NPR-A genotypes under baseline conditions. TRAP and LPS increased lung W/D weight and BAL fluid cell counts more in NPR-A-/- mice than in NPR-A+/- or NPR-A+/+ mice, but no genotype-related differences were seen in TRAP-induced increases in bloodless lung W/D weight or LPS-induced increases in BAL protein concentration. Pretreatment with ANP infusion completely blocked TRAP-induced increases in lung W/D weight and blunted LPS-induced increases in BAL cell counts and protein concentration in both NPR-A-/- and NPR-A+/+ mice. Thrombin decreased transmembrane electrical resistance in monolayers of PMVECs in vitro, and this effect was attenuated by ANP in PMVECs isolated from both genotypes. Administration of the NPR-C-specific ligand, cANF, also blocked TRAP-induced increases in lung W/D weight and LPS-induced increases in BAL cell count and protein concentration in NPR-A+/+ and NPR-A-/- mice. We conclude that ANP is capable of attenuating agonist-induced lung edema in the absence of NPR-A. The protective effect of ANP on agonist-induced lung injury and pulmonary barrier function may be mediated by NPR-C.
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Affiliation(s)
- James R Klinger
- Vascular Research Laboratory, Veterans Affairs Medical Center, Providence, RI, USA.
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160
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Li L, Lai EY, Huang Y, Eisner C, Mizel D, Wilcox CS, Schnermann J. Renal afferent arteriolar and tubuloglomerular feedback reactivity in mice with conditional deletions of adenosine 1 receptors. Am J Physiol Renal Physiol 2012; 303:F1166-75. [PMID: 22896040 PMCID: PMC3469676 DOI: 10.1152/ajprenal.00222.2012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Accepted: 08/13/2012] [Indexed: 11/22/2022] Open
Abstract
Adenosine 1 receptors (A1AR) have been shown in previous experiments to play a major role in the tubuloglomerular feedback (TGF) constrictor response of afferent arterioles (AA) to increased loop of Henle flow. Overexpression studies have pointed to a critical role of vascular A1AR, but it has remained unclear whether selective deletion of A1AR from smooth muscle cells is sufficient to abolish TGF responsiveness. To address this question, we have determined TGF response magnitude in mice in which vascular A1AR deletion was achieved using the loxP recombination approach with cre recombinase being controlled by a smooth muscle actin promoter (SmCre/A1ARff). Effective vascular deletion of A1AR was affirmed by absence of vasoconstrictor responses to adenosine or cyclohexyl adenosine (CHA) in microperfused AA. Elevation of loop of Henle flow from 0 to 30 nl/min caused a 22.1 ± 3.1% reduction of stop flow pressure in control mice and of 7.2 ± 1.5% in SmCre/A1ARff mice (P < 0.001). Maintenance of residual TGF activity despite absence of A1AR-mediated responses in AA suggests participation of extravascular A1AR in TGF. Support for this notion comes from the observation that deletion of A1ARff by nestin-driven cre causes an identical TGF response reduction (7.3 ± 2.4% in NestinCre/A1ARff vs. 20.3 ± 2.7% in controls), whereas AA responsiveness was reduced but not abolished. A1AR on AA smooth muscle cells are primarily responsible for TGF activation, but A1AR on extravascular cells, perhaps mesangial cells, appear to contribute to the TGF response.
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Affiliation(s)
- Lingli Li
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 10 Center Drive-MSC 1370, Bethesda, MD 20892, USA
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161
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Fox EA, Biddinger JE, Jones KR, McAdams J, Worman A. Mechanism of hyperphagia contributing to obesity in brain-derived neurotrophic factor knockout mice. Neuroscience 2012; 229:176-99. [PMID: 23069761 DOI: 10.1016/j.neuroscience.2012.09.078] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Revised: 09/28/2012] [Accepted: 09/28/2012] [Indexed: 10/27/2022]
Abstract
Global-heterozygous and brain-specific homozygous knockouts (KOs) of brain-derived neurotrophic factor (BDNF) cause late- and early-onset obesity, respectively, both involving hyperphagia. Little is known about the mechanism underlying this hyperphagia or whether BDNF loss from peripheral tissues could contribute to overeating. Since global-homozygous BDNF-KO is perinatal lethal, a BDNF-KO that spared sufficient brainstem BDNF to support normal health was utilized to begin to address these issues. Meal pattern and microstructure analyses suggested overeating of BDNF-KO mice was mediated by deficits in both satiation and satiety that resulted in increased meal size and frequency and implicated a reduction of vagal signaling from the gut to the brain. Meal-induced c-Fos activation in the nucleus of the solitary tract, a more direct measure of vagal afferent signaling, however, was not decreased in BDNF-KO mice, and thus was not consistent with a vagal afferent role. Interestingly though, meal-induced c-Fos activation was increased in the dorsal motor nucleus of the vagus nerve (DMV) of BDNF-KO mice. This could imply that augmentation of vago-vagal digestive reflexes occurred (e.g., accommodation), which would support increased meal size and possibly increased meal number by reducing the increase in intragastric pressure produced by a given amount of ingesta. Additionally, vagal sensory neuron number in BDNF-KO mice was altered in a manner consistent with the increased meal-induced activation of the DMV. These results suggest reduced BDNF causes satiety and satiation deficits that support hyperphagia, possibly involving augmentation of vago-vagal reflexes mediated by central pathways or vagal afferents regulated by BDNF levels.
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Affiliation(s)
- E A Fox
- Behavioral Neurogenetics Laboratory, Department of Psychological Sciences, Purdue University, West Lafayette, IN 47907, USA.
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162
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Pandey KN. Emerging Roles of Natriuretic Peptides and their Receptors in Pathophysiology of Hypertension and Cardiovascular Regulation. ACTA ACUST UNITED AC 2012; 2:210-26. [PMID: 19746200 DOI: 10.1016/j.jash.2008.02.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Thus far, three related natriuretic peptides (NPs) and three distinct receptors have been identified, which have advanced our knowledge towards understanding the control of high blood pressure, hypertension, and cardiovascular disorders to a great extent. Biochemical and molecular studies have been advanced to examine receptor function and signaling mechanisms and the role of second messenger cGMP in pathophysiology of hypertension, renal hemodynamics, and cardiovascular functions. The development of gene-knockout and gene-duplication mouse models along with transgenic mice have provided a framework for understanding the importance of the antagonistic actions of natriuretic peptides receptor in cardiovascular events at the molecular level. Now, NPs are considered as circulating markers of congestive heart failure, however, their therapeutic potential for the treatment of cardiovascular diseases such as hypertension, renal insufficiency, cardiac hypertrophy, congestive heart failure, and stroke has just begun to unfold. Indeed, the alternative avenues of investigations in this important are need to be undertaken, as we are at the initial stage of the molecular therapeutic and pharmacogenomic implications.
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Affiliation(s)
- Kailash N Pandey
- Department of Physiology, Tulane University School of Medicine, New Orleans, LA 70112
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163
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Prieto MC, Das S, Somanna NK, Harrison-Bernard LM, Navar LG, Pandey KN. Disruption of Npr1 gene differentially regulates the juxtaglomerular and distal tubular renin levels in null mutant mice. INTERNATIONAL JOURNAL OF PHYSIOLOGY, PATHOPHYSIOLOGY AND PHARMACOLOGY 2012; 4:128-139. [PMID: 23071870 PMCID: PMC3466495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 08/12/2012] [Accepted: 09/07/2012] [Indexed: 06/01/2023]
Abstract
Atrial natriuretic peptide (ANP) exerts an inhibitory effect on juxtaglomerular (JG) renin synthesis and release by activating guanylyl cyclase/ natriuretic peptide receptor-A (GC-A/NPRA). Renin has also been localized in connecting tubule cells; however, the effect of ANP/NPRA signaling on tubular renin has not been determined. In the present study, we determined the role of NPRA in regulating both JG and tubular renin using Npr1 (coding for NPRA) gene-disrupted mice, which exhibit a hypertensive phenotype. Renin-positive immunoreactivity in Npr1(-/-) homozygous null mutant mice was significantly reduced compared with Npr1(+/+) wild-type mice (23% vs 69% renin-positive glomeruli). However, after chronic diuretic treatment, Npr1(-/-) mice showed an increment of JG renin immunoreactivity compared with Npr1(+/+) mice (70% vs 81% renin-positive glomeruli). There were no significant differences in the distal tubule renin between Npr1(+/+) and Npr1(-/-) mice. However, after diuretic treatment, Npr1(-/-) mice showed a significant decrease in renin immunoreactivity in principal cells of cortical collecting ducts (p<0.05). The increased JG renin immunoreactivity after reduction in blood pressure in diuretic-treated Npr1(-/-) mice, demonstrates an inhibitory action of ANP/NPRA system on JG renin; however, a decreased expression of distal tubular renin suggests a differential effect of ANP/NPRA signaling on JG and distal tubular renin.
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Affiliation(s)
- Minolfa C Prieto
- Department of Physiology, Tulane University Health Sciences CenterNew Orleans, LA 70112, USA
| | - Subhankar Das
- Department of Physiology, Tulane University Health Sciences CenterNew Orleans, LA 70112, USA
| | - Naveen K Somanna
- Department of Physiology, Tulane University Health Sciences CenterNew Orleans, LA 70112, USA
| | | | - L Gabriel Navar
- Department of Physiology, Tulane University Health Sciences CenterNew Orleans, LA 70112, USA
| | - Kailash N Pandey
- Department of Physiology, Tulane University Health Sciences CenterNew Orleans, LA 70112, USA
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164
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Abstract
The cardiac hormone atrial natriuretic peptide (ANP) is critically involved in the maintenance of arterial blood pressure and intravascular volume homeostasis. Its cGMP-producing GC-A receptor is densely expressed in the microvascular endothelium of the lung and systemic circulation, but the functional relevance is controversial. Some studies reported that ANP stimulates endothelial cell permeability, whereas others described that the peptide attenuates endothelial barrier dysfunction provoked by inflammatory agents such as thrombin or histamine. Many studies in vitro addressed the effects of ANP on endothelial proliferation and migration. Again, both pro- and anti-angiogenic properties were described. To unravel the role of the endothelial actions of ANP in vivo, we inactivated the murine GC-A gene selectively in endothelial cells by homologous loxP/Cre-mediated recombination. Our studies in these mice indicate that ANP, via endothelial GC-A, increases endothelial albumin permeability in the microcirculation of the skin and skeletal muscle. This effect is critically involved in the endocrine hypovolaemic, hypotensive actions of the cardiac hormone. On the other hand the homologous GC-A-activating B-type NP (BNP), which is produced by cardiac myocytes and many other cell types in response to stressors such as hypoxia, possibly exerts more paracrine than endocrine actions. For instance, within the ischaemic skeletal muscle BNP released from activated satellite cells can improve the regeneration of neighbouring endothelia. This review will focus on recent advancements in our understanding of endothelial NP/GC-A signalling in the pulmonary versus systemic circulation. It will discuss possible mechanisms accounting for the discrepant observations made for the endothelial actions of this hormone-receptor system and distinguish between (patho)physiological and pharmacological actions. Lastly it will emphasize the potential therapeutical implications derived from the actions of NPs on endothelial permeability and regeneration.
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Affiliation(s)
- Michaela Kuhn
- Physiologisches Institut der Universität Würzburg, Würzburg, Germany.
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165
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Fox EA, Biddinger JE. Early postnatal overnutrition: potential roles of gastrointestinal vagal afferents and brain-derived neurotrophic factor. Physiol Behav 2012; 106:400-12. [PMID: 22712064 PMCID: PMC3517218 DOI: 10.1016/j.physbeh.2012.04.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Abnormal perinatal nutrition (APN) results in a predisposition to develop obesity and the metabolic syndrome and thus may contribute to the prevalence of these disorders. Obesity, including that which develops in organisms exposed to APN, has been associated with increased meal size. Vagal afferents of the gastrointestinal (GI) tract contribute to regulation of meal size by transmitting satiation signals from gut-to-brain. Consequently, APN could increase meal size by altering this signaling, possibly through changes in expression of factors that control vagal afferent development or function. Here two studies that addressed these possibilities are reviewed. First, meal patterns, meal microstructure, and the structure and density of vagal afferents that innervate the intestine were examined in mice that experienced early postnatal overnutrition (EPO). These studies provided little evidence for EPO effects on vagal afferents as it did not alter meal size or vagal afferent density or structure. However, these mice exhibited modest hyperphagia due to a satiety deficit. In parallel, the possibility that brain-derived neurotrophic factor (BDNF) could mediate APN effects on vagal afferent development was investigated. Brain-derived neurotrophic factor was a strong candidate because APN alters BDNF levels in some tissues and BDNF knockout disrupts development of vagal sensory innervation of the GI tract. Surprisingly, smooth muscle-specific BDNF knockout resulted in early-onset obesity and hyperphagia due to increases in meal size and frequency. Microstructure analysis revealed decreased decay of intake rate during a meal in knockouts, suggesting that the loss of vagal negative feedback contributed to their increase in meal size. However, meal-induced c-Fos activation within the dorsal vagal complex suggested this effect could be due to augmentation of vago-vagal reflexes. A model is proposed to explain how high-fat diet consumption produces increased obesity in organisms exposed to APN, and may be required to reveal effects of EPO on vagal function.
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Affiliation(s)
- Edward A Fox
- Behavioral Neurogenetics Laboratory & Ingestive Behavior Research Center, Department of Psychological Sciences, Purdue University, West Lafayette, IN 47907, USA.
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166
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Chromatin-remodeling complex specificity and embryonic vascular development. Cell Mol Life Sci 2012; 69:3921-31. [PMID: 22618247 DOI: 10.1007/s00018-012-1023-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 04/12/2012] [Accepted: 05/02/2012] [Indexed: 12/27/2022]
Abstract
Vascular development is a dynamic process that relies on the coordinated expression of numerous genes, but the factors that regulate gene expression during blood vessel development are not well defined. ATP-dependent chromatin-remodeling complexes are gaining attention for their specific temporal and spatial effects on gene expression during vascular development. Genetic mutations in chromatin-remodeling complex subunits are revealing roles for the complexes in vascular signaling pathways at discrete developmental time points. Phenotypic analysis of these models at various stages of vascular development will continue to expand our understanding of how chromatin remodeling impacts new blood vessel growth. Such research could also provide novel therapeutic targets for the treatment of vascular pathologies.
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167
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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] [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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168
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Nishida Y, Tandai-Hiruma M, Kemuriyama T, Hagisawa K. Long-term blood pressure control: is there a set-point in the brain? J Physiol Sci 2012; 62:147-61. [PMID: 22302247 PMCID: PMC10717488 DOI: 10.1007/s12576-012-0192-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Accepted: 01/04/2012] [Indexed: 01/11/2023]
Abstract
Mean arterial pressure fluctuates depending on physical or psychological activity, but should be stable at rest at around 100 mmHg throughout an entire life in human. The causes of hypertension and the blood pressure regulation mechanisms have been discussed for a long time, and many aspects have recently become more clear. Circulatory shock or short-term hypotension can be treated based on what is now known, but chronic hypertension is still difficult to treat thoroughly. The exact mechanisms for long-term blood pressure regulation have yet not been elucidated. Neuro–humoral interaction has been suggested as one of the mechanisms. Then, from the 1990s, paracrine hormones like nitric oxide or endothelins have been extensively researched in order to develop endothelial local control mechanisms for blood pressure, which have some relationships to long-term control. Although these new ideas and mechanisms are newly developed, no clear explanation for long-term control has yet been discussed, except for renal abnormality. Recently, a central set-point theory has begun to be discussed. This review will discuss the mechanisms for long-term blood pressure control, based on putative biological missions of circulatory function for life support.
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Affiliation(s)
- Yasuhiro Nishida
- Department of Physiology, National Defense Medical College, Namiki 3-2, Tokorozawa, Saitama 359-8513, Japan.
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169
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Abstract
The natriuretic peptides, specifically atrial natriuretic peptide (ANP), are increasingly recognized to play a fundamental role in blood pressure (BP) regulation. This role in BP regulation reflects the pluripotent cardiorenal actions of ANP, which include diuresis, enhancement of renal blood flow and glomerular filtration rate, systemic vasodilatation, suppression of aldosterone, and inhibition of the sympathetic nervous system. These actions of ANP, in addition to recent human studies demonstrating an association of higher plasma ANP with lower risk of hypertension, support the development of an ANP-based therapy for hypertension. M-ANP is a novel ANP-based peptide that is resistant to proteolytic degradation and possesses greater BP-lowering, renal function-enhancing, and aldosterone-suppressing properties than native ANP. In an animal model of hypertension, M-ANP lowers BP via multiple mechanisms, including vasodilatation, diuresis, and inhibition of aldosterone. Importantly, M-ANP enhances both glomerular filtration rate and renal blood flow despite reductions in BP. The pluripotent BP-lowering actions and concomitant enhancement of renal function associated with M-ANP are highly attractive characteristics for an antihypertensive agent and underscore the therapeutic potential of M-ANP. M-ANP currently is heading into clinical testing, which may advance this novel strategy for human hypertension.
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170
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Zhang X, Thatcher SE, Rateri DL, Bruemmer D, Charnigo R, Daugherty A, Cassis LA. Transient exposure of neonatal female mice to testosterone abrogates the sexual dimorphism of abdominal aortic aneurysms. Circ Res 2012; 110:e73-85. [PMID: 22539767 DOI: 10.1161/circresaha.111.253880] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
RATIONALE Abdominal aortic aneurysms (AAAs) exhibit marked sexual dimorphism with higher prevalence in men. Similarly, AAAs induced by angiotensin II (AngII) infusion into mice exhibit a higher prevalence in males. Testosterone promotes AAA pathology in adult male mice through regulation of angiotensin type 1A receptors (AT1aR) in abdominal aortas. However, mechanisms for sexual dimorphism of regional aortic angiotensin receptor expression and AAA formation are unknown. OBJECTIVE To define the role of developmental testosterone exposures in sexual dimorphism of AAAs, we determined if exposure of neonatal female mice to testosterone confers adult susceptibility to AngII-induced AAAs. METHODS AND RESULTS One-day-old female hypercholesterolemic mice were administered a single dose of either vehicle or testosterone. Neonatal testosterone administration increased abdominal aortic AT1aR mRNA abundance and promoted a striking increase in AngII-induced AAAs in adult females exhibiting low serum testosterone concentrations. AngII-induced atherosclerosis and ascending aortic aneurysms were also increased by testosterone administration to neonatal females. In contrast, neonatal testosterone administration in males had no effect on AngII-induced vascular pathologies. Deficiency of AT1aR in smooth muscle cells reduced effects of neonatal testosterone to promote AAAs in adult females but did not alter atherosclerosis or ascending aortic aneurysms. Testosterone increased AT1aR mRNA abundance and hydrogen peroxide generation in cultured abdominal aortic SMCs. Increased AT1aR mRNA abundance was maintained during progressive passaging of female smooth muscle cells. CONCLUSIONS These data reveal an unrecognized role of transient sex hormone exposures during neonatal development as long-lasting mediators of regional aortic AT1aR expression and sexual dimorphism of AAAs.
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Affiliation(s)
- Xuan Zhang
- Graduate Center for Toxicology, University of Kentucky, Lexington, KY 40536-0200, USA
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171
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Chen Z, Wu J, Yang C, Fan P, Balazs L, Jiao Y, Lu M, Gu W, Li C, Pfeffer LM, Tigyi G, Yue J. DiGeorge syndrome critical region 8 (DGCR8) protein-mediated microRNA biogenesis is essential for vascular smooth muscle cell development in mice. J Biol Chem 2012; 287:19018-28. [PMID: 22511778 DOI: 10.1074/jbc.m112.351791] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
DiGeorge Critical Region 8 (DGCR8) is a double-stranded RNA-binding protein that interacts with Drosha and facilitates microRNA (miRNA) maturation. However, the role of DGCR8 in vascular smooth muscle cells (VSMCs) is not well understood. To investigate whether DGCR8 contributes to miRNA maturation in VSMCs, we generated DGCR8 conditional knockout (cKO) mice by crossing VSMC-specific Cre mice (SM22-Cre) with DGCR8(loxp/loxp) mice. We found that loss of DGCR8 in VSMCs resulted in extensive liver hemorrhage and embryonic mortality between embryonic days (E) 12.5 and E13.5. DGCR8 cKO embryos displayed dilated blood vessels and disarrayed vascular architecture. Blood vessels were absent in the yolk sac of DGCR8 KOs after E12.5. Disruption of DGCR8 in VSMCs reduced VSMC proliferation and promoted apoptosis in vitro and in vivo. In DGCR8 cKO embryos and knockout VSMCs, differentiation marker genes, including αSMA, SM22, and CNN1, were significantly down-regulated, and the survival pathways of ERK1/2 mitogen-activated protein kinase and the phosphatidylinositol 3-kinase/AKT were attenuated. Knockout of DGCR8 in VSMCs has led to down-regulation of the miR-17/92 and miR-143/145 clusters. We further demonstrated that the miR-17/92 cluster promotes VSMC proliferation and enhances VSMC marker gene expression, which may contribute to the defects of DGCR8 cKO mutants. Our results indicate that the DGCR8 gene is required for vascular development through the regulation of VSMC proliferation, apoptosis, and differentiation.
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Affiliation(s)
- Zixuan Chen
- Department of Physiology, Campbell Clinic, University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA
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172
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De Gendt K, Verhoeven G. Tissue- and cell-specific functions of the androgen receptor revealed through conditional knockout models in mice. Mol Cell Endocrinol 2012; 352:13-25. [PMID: 21871526 DOI: 10.1016/j.mce.2011.08.008] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Revised: 07/18/2011] [Accepted: 08/10/2011] [Indexed: 12/28/2022]
Abstract
This review aims to evaluate the contribution of individual cell-selective knockout models to our current understanding of androgen action. Cre/loxP technology has allowed the generation of cell-selective knockout models targeting the androgen receptor (AR) in distinct putative target cells in a wide variety of organs and tissues including: testis, ovary, accessory sex tissues, muscle, bone, fat, liver, skin and myeloid tissue. In some androgen-regulated processes such as spermatogenesis and folliculogenesis this approach has lead to the identification of a key cellular mediator of androgen action (Sertoli and granulosa cells, respectively). In many target tissues, however, the final response to androgens appears to be more complex. Here, cell-selective knockout technology offers a platform upon which we can begin to unravel the more complex interplay and signaling pathways of androgens. A prototypic example is the analysis of mesenchymal-epithelial interactions in many accessory sex glands. Furthermore, for some actions of testosterone, in which part of the effect is mediated by the active metabolite 17β-estradiol, conditional knockout technology offers a novel strategy to study the relative contribution of AR and estrogen receptor-mediated signaling. The latter approach has already resulted in a better understanding of androgen action in brain and bone. Finally, cell-selective knockout technology has generated valuable models to search for AR-controlled molecular mediators of androgen action, a strategy that has successfully been applied to the study of androgen action in the testis and in the epididymis. Although some conditional knockout models have provided clear answers to physiologic questions, it should be noted that others have pointed to unexpected complexities or technical limitations confounding interpretation of the results.
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Affiliation(s)
- Karel De Gendt
- Laboratory for Experimental Medicine and Endocrinology, Catholic University of Leuven, Leuven, Belgium
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173
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Lopes M, Goupille O, Saint Cloment C, Robert B. Msx1 is expressed in retina endothelial cells at artery branching sites. Biol Open 2012; 1:376-84. [PMID: 23213427 PMCID: PMC3509462 DOI: 10.1242/bio.2012017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Msx1 and Msx2 encode homeodomain transcription factors that play a role in several embryonic developmental processes. Previously, we have shown that in the adult mouse, Msx1(lacZ) is expressed in vascular smooth muscle cells (VSMCs) and pericytes, and that Msx2(lacZ) is also expressed in VSMCs as well as in a few endothelial cells (ECs). The mouse retina and choroid are two highly vascularized tissues. Vessel alterations in the retina are associated with several human diseases and the retina has been intensely used for angiogenesis studies, whereas the choroid has been much less investigated. Using the Msx1(lacZ) and Msx2(lacZ) reporter alleles, we observed that Msx2 is not expressed in the eye vascular tree in contrast to Msx1, for which we establish the spatial and temporal expression pattern in these tissues. In the retina, expression of Msx1 takes place from P3, and by P10, it becomes confined to a subpopulation of ECs at branching points of superficial arterioles. These branching sites are characterized by a subpopulation of mural cells that also show specific expression programs. Specific Msx gene inactivation in the endothelium, using Msx1 and Msx2 conditional mutant alleles together with a Tie2-Cre transgene, did not lead to conspicuous structural defects in the retinal vascular network. Expression of Msx1 at branching sites might therefore be linked to vessel physiology. The retinal blood flow is autonomously regulated and perfusion of capillaries has been proposed to depend on arteriolar precapillary structures that might be the sites for Msx1 expression. On the other hand, branching sites are subject to shear stress that might induce Msx1 expression. In the choroid vascular layer Msx1(lacZ) is expressed more broadly and dynamically. At birth Msx1(lacZ) expression takes place in the endothelium but at P21 its expression has shifted towards the mural layer. We discuss the possible functions of Msx1 in the eye vasculature.
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Affiliation(s)
- Miguel Lopes
- Present address: IPSEN Innovation, Scientific affairs department, 5 Avenue du Canada, 91966 Les Ulis Cedex, France
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174
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Gruzdev A, Nguyen M, Kovarova M, Koller BH. PGE2 through the EP4 receptor controls smooth muscle gene expression patterns in the ductus arteriosus critical for remodeling at birth. Prostaglandins Other Lipid Mediat 2012; 97:109-19. [PMID: 22342504 DOI: 10.1016/j.prostaglandins.2012.02.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Revised: 02/01/2012] [Accepted: 02/02/2012] [Indexed: 10/14/2022]
Abstract
The ductus arteriosus (DA) is a fetal shunt that directs right ventricular outflow away from pulmonary circulation and into the aorta. Critical roles for prostaglandin E(2) (PGE(2)) and the EP4 receptor (EP4) have been established in maintaining both the patency of the vessel in utero and in its closure at birth. Here we have generated mice in which loss of EP4 expression is limited to either the smooth muscle (SMC) or endothelial cells and demonstrated that SMC, but not endothelial cell expression of EP4 is required for DA closure. The genome wide expression analysis of full term wild type and EP4(-/-) DA indicates that PGE(2)/EP4 signaling modulates expression of a number of unique pathways, including those involved in SMC proliferation, cell migration, and vascular tone. Together this supports a mechanism by which maturation and increased contractility of the vessel is coupled to the potent smooth muscle dilatory actions of PGE(2).
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Affiliation(s)
- Artiom Gruzdev
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7248, USA
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175
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Turlo KA, Noel ODV, Vora R, LaRussa M, Fassler R, Hall-Glenn F, Iruela-Arispe ML. An essential requirement for β1 integrin in the assembly of extracellular matrix proteins within the vascular wall. Dev Biol 2012; 365:23-35. [PMID: 22331032 DOI: 10.1016/j.ydbio.2012.01.027] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Revised: 12/30/2011] [Accepted: 01/30/2012] [Indexed: 01/22/2023]
Abstract
β1 integrin has been shown to contribute to vascular smooth muscle cell differentiation, adhesion and mechanosensation in vitro. Here we showed that deletion of β1 integrin at the onset of smooth muscle differentiation resulted in interrupted aortic arch, aneurysms and failure to assemble extracellular matrix proteins. These defects result in lethality prior to birth. Our data indicates that β1 integrin is not required for the acquisition, but it is essential for the maintenance of the smooth muscle cell phenotype, as levels of critical smooth muscle proteins are gradually reduced in mutant mice. Furthermore, while deposition of extracellular matrix was not affected, its structure was disrupted. Interestingly, defects in extracellular matrix and vascular wall assembly, were restricted to the aortic arch and its branches, compromising the brachiocephalic and carotid arteries and to the exclusion of the descending aorta. Additional analysis of β1 integrin in the pharyngeal arch smooth muscle progenitors was performed using wnt1Cre. Neural crest cells deleted for β1 integrin were able to migrate to the pharyngeal arches and associate with endothelial lined arteries; but exhibited vascular remodeling defects and early lethality. This work demonstrates that β1 integrin is dispensable for migration and initiation of the smooth muscle differentiation program, however, it is essential for remodeling of the pharyngeal arch arteries and for the assembly of the vessel wall of their derivatives. It further establishes a critical role of β1 integrin in the protection against aneurysms that is particularly confined to the ascending aorta and its branches.
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Affiliation(s)
- Kirsten A Turlo
- Department of Molecular, Cellular, and Developmental Biology, University of California, Los Angeles, CA 90095, USA
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176
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Milton I, Ouyang D, Allen CJ, Yanasak NE, Gossage JR, Alleyne CH, Seki T. Age-dependent lethality in novel transgenic mouse models of central nervous system arteriovenous malformations. Stroke 2012; 43:1432-5. [PMID: 22328553 DOI: 10.1161/strokeaha.111.647024] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE The lack of an appropriate animal model has been a limitation in studying hemorrhage from arteriovenous malformations (AVMs) in the central nervous system. METHODS Novel mouse central nervous system AVM models were generated by conditionally deleting the activin receptor-like kinase (Alk1; Acvrl1) gene with the SM22-Cre transgene. All mice developed AVMs in their brain and/or spinal cord, and >80% of them showed a paralysis or lethality phenotype due to internal hemorrhages during the first 10 to 15 weeks of life. The mice that survived this early lethal period, however, showed significantly reduced lethality rates even though they carried multiple AVMs. RESULTS The age-dependent change in hemorrhage rates allowed us to identify molecular factors uniquely upregulated in the rupture-prone AVM lesions. CONCLUSIONS Upregulation of angiopoietin 2 and a few inflammatory genes were identified in the hemorrhage-prone lesions, which may be comparable with human pathology. These models will be an exceptional tool to study pathophysiology of AVM hemorrhage.
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Affiliation(s)
- Ian Milton
- Georgia Health Sciences University, Augusta, GA 30912, USA
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177
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Kaftanovskaya EM, Huang Z, Barbara AM, De Gendt K, Verhoeven G, Gorlov IP, Agoulnik AI. Cryptorchidism in mice with an androgen receptor ablation in gubernaculum testis. Mol Endocrinol 2012; 26:598-607. [PMID: 22322597 DOI: 10.1210/me.2011-1283] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Androgens play a critical role in the development of the male reproductive system, including the positioning of the gonads. It is not clear, however, which developmental processes are influenced by androgens and what are the target tissues and cells mediating androgen signaling during testicular descent. Using a Cre-loxP approach, we have produced male mice (GU-ARKO) with conditional inactivation of the androgen receptor (Ar) gene in the gubernacular ligament connecting the epididymis to the caudal abdominal wall. The GU-ARKO males had normal testosterone levels but developed cryptorchidism with the testes located in a suprascrotal position. Although initially subfertile, the GU-ARKO males became sterile with age. We have shown that during development, the mutant gubernaculum failed to undergo eversion, a process giving rise to the processus vaginalis, a peritoneal outpouching inside the scrotum. As a result, the cremasteric sac did not form properly, and the testes remained in the low abdominal position. Abnormal development of the cremaster muscles in the GU-ARKO males suggested the participation of androgens in myogenic differentiation; however, males with conditional AR inactivation in the striated or smooth muscle cells had a normal testicular descent. Gene expression analysis showed that AR deficiency in GU-ARKO males led to the misexpression of genes involved in muscle differentiation, cell signaling, and extracellular space remodeling. We therefore conclude that AR signaling in gubernacular cells is required for gubernaculum eversion and outgrowth. The GU-ARKO mice provide a valuable model of isolated cryptorchidism, one of the most common birth defects in newborn boys.
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Affiliation(s)
- Elena M Kaftanovskaya
- Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, 11200 SW 8th Street, Miami, Florida 33199, USA
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178
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Lai KP, Yamashita S, Vitkus S, Shyr CR, Yeh S, Chang C. Suppressed prostate epithelial development with impaired branching morphogenesis in mice lacking stromal fibromuscular androgen receptor. Mol Endocrinol 2011; 26:52-66. [PMID: 22135068 DOI: 10.1210/me.2011-1189] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Using the cre-loxP system, we generated a new mouse model [double stromal androgen receptor knockout (dARKO)] with selectively deleted androgen receptor (AR) in both stromal fibroblasts and smooth muscle cells, and found the size of the anterior prostate (AP) lobes was significantly reduced as compared with those from wild-type littermate controls. The reduction in prostate size of the dARKO mouse was accompanied by impaired branching morphogenesis and partial loss of the infolding glandular structure. Further dissection found decreased proliferation and increased apoptosis of the prostate epithelium in the dARKO mouse AP. These phenotype changes were further confirmed with newly established immortalized prostate stromal cells (PrSC) from wild-type and dARKO mice. Mechanistically, IGF-1, placental growth factor, and secreted phosphoprotein-1 controlled by stromal AR were differentially expressed in PrSC-wt and PrSC-ARKO. Moreover, the conditioned media (CM) from PrSC-wt promoted prostate epithelium growth significantly as compared with CM from PrSC-dARKO. Finally, adding IGF-1/placental growth factor recombinant proteins into PrSC-dARKO CM was able to partially rescue epithelium growth. Together, our data concluded that stromal fibromuscular AR could modulate epithelium growth and maintain cellular homeostasis through identified growth factors.
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Affiliation(s)
- Kuo-Pao Lai
- George H Whipple Laboratory for Cancer Research, University of Rochester Medical Center, Rochester, New York 14642, USA
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179
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Jaffe M, Sesti C, Washington IM, Du L, Dronadula N, Chin MT, Stolz DB, Davis EC, Dichek DA. Transforming growth factor-β signaling in myogenic cells regulates vascular morphogenesis, differentiation, and matrix synthesis. Arterioscler Thromb Vasc Biol 2011; 32:e1-11. [PMID: 21979435 DOI: 10.1161/atvbaha.111.238410] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE Transforming growth factor-β (TGF-β) signaling is required for normal vascular development. We aimed to discover the role of TGF-β signaling in embryonic smooth muscle cells (SMCs). METHODS AND RESULTS We bred mice with smooth muscle (SM) 22α-Cre and Tgfbr2(flox) alleles to generate embryos in which the type II TGF-β receptor (TGFBR2; required for TGF-β signaling) was deleted in SMCs. Embryos were harvested between embryonic day (E) 9.5 and E18.5 and examined grossly, microscopically, and by histochemical and RNA analyses. SM22α-Cre(+/0) Tgfbr2(flox/flox) (knockout [KO]) embryos died before E15.5 with defects that included cardiac outflow tract abnormalities, persistence of the right dorsal aorta, and dilation of the distal aorta. Histological analyses suggested normal expression of SMC differentiation markers in KO aortas; however, RNA analyses showed that SMC differentiation markers were increased in KO cardiac outflow vessels but decreased in the descending aorta. KO aortas had only rare mature elastin deposits and contained abnormal aggregates of extracellular matrix proteins. Expression of several matrix proteins was significantly decreased in KO descending aortas but not in cardiac outflow vessels. CONCLUSIONS TGF-β signaling in SMCs controls differentiation, matrix synthesis, and vascular morphogenesis. Effects of TGF-β on SMC gene expression appear to differ depending on the location of SMCs in the aorta.
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Affiliation(s)
- Mia Jaffe
- Division of Cardiology, Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA
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180
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Cannone V, Boerrigter G, Cataliotti A, Costello-Boerrigter LC, Olson TM, McKie PM, Heublein DM, Lahr BD, Bailey KR, Averna M, Redfield MM, Rodeheffer RJ, Burnett JC. A genetic variant of the atrial natriuretic peptide gene is associated with cardiometabolic protection in the general community. J Am Coll Cardiol 2011; 58:629-36. [PMID: 21798427 DOI: 10.1016/j.jacc.2011.05.011] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Revised: 04/14/2011] [Accepted: 05/15/2011] [Indexed: 11/25/2022]
Abstract
OBJECTIVES We sought to define the cardiometabolic phenotype associated with rs5068, a genetic variant of the atrial natriuretic peptide (ANP) gene. BACKGROUND The ANP and B-type natriuretic peptide play an important role in cardiorenal homeostasis but also exert metabolic actions. METHODS We genotyped 1,608 randomly selected residents from Olmsted County, Minnesota. Subjects were well-characterized. RESULTS Genotype frequencies were: AA 89.9%, AG 9.7%, and GG 0.4%; all subsequent analyses were AA versus AG+GG. The G allele was associated with increased plasma levels of N-terminal pro-atrial natriuretic peptide (p = 0.002), after adjustment for age and sex. The minor allele was also associated with lower body mass index (BMI) (p = 0.006), prevalence of obesity (p = 0.002), waist circumference (p = 0.021), lower levels of C-reactive protein (p = 0.027), and higher values of high-density lipoprotein cholesterol (p = 0.019). The AG+GG group had a lower systolic blood pressure (p = 0.011) and lower prevalence of myocardial infarction (p = 0.042). The minor allele was associated with a lower prevalence of metabolic syndrome (p = 0.025). The associations between the G allele and high-density lipoprotein cholesterol, C-reactive protein values, myocardial infarction, and metabolic syndrome were not significant, after adjusting for BMI; the associations with systolic blood pressure, BMI, obesity, and waist circumference remained significant even after adjusting for N-terminal pro-atrial natriuretic peptide. CONCLUSIONS In a random sample of the general U.S. population, the minor allele of rs5068 is associated with a favorable cardiometabolic profile. These findings suggest that rs5068 or genetic loci in linkage disequilibrium might affect susceptibility for cardiometabolic diseases and support the possible protective role of natriuretic peptides by their favorable effects on metabolic function. Replication studies are needed to confirm our findings.
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Affiliation(s)
- Valentina Cannone
- Cardiorenal Research Laboratory, Division of Cardiovascular Diseases, Mayo Clinic and Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA.
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181
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Rindler TN, Dostanic I, Lasko VM, Nieman ML, Neumann JC, Lorenz JN, Lingrel JB. Knockout of the Na,K-ATPase α₂-isoform in the cardiovascular system does not alter basal blood pressure but prevents ACTH-induced hypertension. Am J Physiol Heart Circ Physiol 2011; 301:H1396-404. [PMID: 21856916 DOI: 10.1152/ajpheart.00121.2011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The α(2)-isoform of Na,K-ATPase (α(2)) is thought to play a role in blood pressure regulation, but the specific cell type(s) involved have not been identified. Therefore, it is important to study the role of the α(2) in individual cell types in the cardiovascular system. The present study demonstrates the role of vascular smooth muscle α(2) in the regulation of cardiovascular hemodynamics. To accomplish this, we developed a mouse model utilizing the Cre/LoxP system to generate a cell type-specific knockout of the α(2) in vascular smooth muscle cells using the SM22α Cre. We achieved a 90% reduction in the α(2)-expression in heart and vascular smooth muscle in the knockout mice. Interestingly, tail-cuff blood pressure analysis reveals that basal systolic blood pressure is unaffected by the knockout of α(2) in the knockout mice. However, knockout mice do fail to develop ACTH-induced hypertension, as seen in wild-type mice, following 5 days of treatment with ACTH (Cortrosyn; wild type = 119.0 ± 6.8 mmHg; knockout = 103.0 ± 2.0 mmHg). These results demonstrate that α(2)-expression in heart and vascular smooth muscle is not essential for regulation of basal systolic blood pressure, but α(2) is critical for blood pressure regulation under chronic stress such as ACTH-induced hypertension.
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Affiliation(s)
- Tara N Rindler
- Department of Molecular Genetics, Biochemistry, and Microbiology, College of Medicine, University of Cincinnati, Cincinnati, Ohio, USA
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182
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Ghosh S, Paez-Cortez JR, Boppidi K, Vasconcelos M, Roy M, Cardoso W, Ai X, Fine A. Activation dynamics and signaling properties of Notch3 receptor in the developing pulmonary artery. J Biol Chem 2011; 286:22678-87. [PMID: 21536678 PMCID: PMC3121411 DOI: 10.1074/jbc.m111.241224] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Revised: 04/20/2011] [Indexed: 11/06/2022] Open
Abstract
Notch3 signaling is fundamental for arterial specification of systemic vascular smooth muscle cells (VSMCs). However, the developmental role and signaling properties of the Notch3 receptor in the mouse pulmonary artery remain unknown. Here, we demonstrate that Notch3 is expressed selectively in pulmonary artery VSMCs, is activated from late fetal to early postnatal life, and is required to maintain the morphological characteristics and smooth muscle gene expression profile of the pulmonary artery after birth. Using a conditional knock-out mouse model, we show that Notch3 receptor activation in VSMCs is Jagged1-dependent. In vitro VSMC lentivirus-mediated Jagged1 knockdown, confocal localization analysis, and co-culture experiments revealed that Notch3 activation is cell-autonomous and occurs through the physical engagement of Notch3 and VSMC-derived Jagged1 in the interior of the same cell. Although the current models of mammalian Notch signaling involve a two-cell system composed of a signal-receiving cell that expresses a Notch receptor on its surface and a neighboring signal-sending cell that provides membrane-bound activating ligand, our data suggest that pulmonary artery VSMC Notch3 activation is cell-autonomous. This unique mechanism of Notch activation may play an important role in the maturation of the pulmonary artery during the transition to air breathing.
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Affiliation(s)
- Shamik Ghosh
- From the Pulmonary Center, Boston University School of Medicine, Boston, Massachusetts 02118, and
| | - Jesus R. Paez-Cortez
- From the Pulmonary Center, Boston University School of Medicine, Boston, Massachusetts 02118, and
| | - Karthik Boppidi
- From the Pulmonary Center, Boston University School of Medicine, Boston, Massachusetts 02118, and
| | - Michelle Vasconcelos
- From the Pulmonary Center, Boston University School of Medicine, Boston, Massachusetts 02118, and
| | - Monideepa Roy
- the Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
| | - Wellington Cardoso
- From the Pulmonary Center, Boston University School of Medicine, Boston, Massachusetts 02118, and
| | - Xingbin Ai
- From the Pulmonary Center, Boston University School of Medicine, Boston, Massachusetts 02118, and
| | - Alan Fine
- From the Pulmonary Center, Boston University School of Medicine, Boston, Massachusetts 02118, and
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183
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Saito Y, Kishimoto I, Nakao K. Roles of guanylyl cyclase--a signaling in the cardiovascular system. Can J Physiol Pharmacol 2011; 89:551-6. [PMID: 21671770 DOI: 10.1139/y11-022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) are cardiac hormones synthesized in and secreted from the heart. ANP and BNP bind the common receptor guanylyl cyclase-A (GC-A) and possess biological actions. Based on their diuretic, natriuretic, and vasodilating activities, they are now widely used as therapeutic agents for heart failure. Roles of endogenous ANP and BNP have been investigated using mice lacking the gene encoding GC-A. Here we describe the recent understanding of roles of GC-A in the cardiovascular system.
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Affiliation(s)
- Yoshihiko Saito
- First Department of Internal Medicine, Nara Medical University, Kashihara, Nara 634-8522, Japan.
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184
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Arthur HM, Bamforth SD. TGFβ signaling and congenital heart disease: Insights from mouse studies. BIRTH DEFECTS RESEARCH. PART A, CLINICAL AND MOLECULAR TERATOLOGY 2011; 91:423-34. [PMID: 21538815 DOI: 10.1002/bdra.20794] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Revised: 01/17/2011] [Accepted: 01/28/2011] [Indexed: 12/14/2022]
Abstract
Transforming growth factor β (TGFβ) regulates one of the major signaling pathways that control tissue morphogenesis. In vitro experiments using heart explants indicated the importance of this signaling pathway for the generation of cushion mesenchymal cells, which ultimately contribute to the valves and septa of the mature heart. Recent advances in mouse genetics have enabled in vivo investigation into the roles of individual ligands, receptors, and coreceptors of this pathway, including investigation of the tissue specificity of these roles in heart development. This work has revealed that (1) cushion mesenchyme can form in the absence of TGFβ signaling, although mesenchymal cell numbers may be misregulated; (2) TGFβ signaling is essential for correct remodeling of the cushions, particularly those of the outflow tract; (3) TGFβ signaling also has a role in ensuring accurate remodeling of the pharyngeal arch arteries to form the mature aortic arch; and (4) mesenchymal cells derived from the epicardium require TGFβ signaling to promote their differentiation to vascular smooth muscle cells to support the coronary arteries. In addition, a mouse genetics approach has also been used to investigate the disease pathogenesis of Loeys-Dietz syndrome, a familial autosomal dominant human disorder characterized by a dilated aortic root, and associated with mutations in the two TGFβ signaling receptor genes, TGFBR1 and TGFBR2. Further important insights are likely as this exciting work progresses.
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Affiliation(s)
- Helen M Arthur
- Institute of Human Genetics, Newcastle University, Newcastle upon Tyne, United Kingdom.
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185
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Kishimoto I, Tokudome T, Nakao K, Kangawa K. Natriuretic peptide system: an overview of studies using genetically engineered animal models. FEBS J 2011; 278:1830-41. [PMID: 21477073 DOI: 10.1111/j.1742-4658.2011.08116.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The mammalian natriuretic peptide system, consisting of at least three ligands and three receptors, plays critical roles in health and disease. Examination of genetically engineered animal models has suggested the significance of the natriuretic peptide system in cardiovascular, renal and skeletal homeostasis. The present review focuses on the in vivo roles of the natriuretic peptide system as demonstrated in transgenic and knockout animal models.
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Affiliation(s)
- Ichiro Kishimoto
- Department of Biochemistry, National Cerebral and Cardiovascular Center Research Institute, Osaka, Japan.
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186
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Hypomorphic Notch 3 alleles link Notch signaling to ischemic cerebral small-vessel disease. Proc Natl Acad Sci U S A 2011; 108:E128-35. [PMID: 21555590 DOI: 10.1073/pnas.1101964108] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The most common monogenic cause of small-vessel disease leading to ischemic stroke and vascular dementia is the neurodegenerative syndrome cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), which is associated with mutations in the Notch 3 receptor. CADASIL pathology is characterized by vascular smooth muscle cell degeneration and accumulation of diagnostic granular osmiophilic material (GOM) in vessels. The functional nature of the Notch 3 mutations causing CADASIL and their mechanistic connection to small-vessel disease and GOM accumulation remain enigmatic. To gain insight into how Notch 3 function is linked to CADASIL pathophysiology, we studied two phenotypically distinct mutations, C455R and R1031C, respectively associated with early and late onset of stroke, by using hemodynamic analyses in transgenic mouse models, receptor activity assays in cell culture, and proteomic examination of postmortem human tissue. We demonstrate that the C455R and R1031C mutations define different hypomorphic activity states of Notch 3, a property linked to ischemic stroke susceptibility in mouse models we generated. Importantly, these mice develop osmiophilic deposits and other age-dependent phenotypes that parallel remarkably the human condition. Proteomic analysis of human brain vessels, carrying the same CADASIL mutations, identified clusterin and collagen 18 α1/endostatin as GOM components. Our findings link loss of Notch signaling with ischemic cerebral small-vessel disease, a prevalent human condition. We determine that CADASIL pathophysiology is associated with hypomorphic Notch 3 function in vascular smooth muscle cells and implicate the accumulation of clusterin and collagen 18 α1/endostatin in brain vessel pathology.
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187
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Schreier B, Döhler M, Rabe S, Schneider B, Schwerdt G, Ruhs S, Sibilia M, Gotthardt M, Gekle M, Grossmann C. Consequences of epidermal growth factor receptor (ErbB1) loss for vascular smooth muscle cells from mice with targeted deletion of ErbB1. Arterioscler Thromb Vasc Biol 2011; 31:1643-52. [PMID: 21512163 DOI: 10.1161/atvbaha.111.223537] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
OBJECTIVE Pathophysiological effects of the epidermal growth factor receptor (EGFR or ErbB1) include vascular remodeling. EGFR transactivation is proposed to contribute significantly to heterologous signaling and remodeling in vascular smooth muscle cells (VSMC). METHODS AND RESULTS We investigated the importance of EGFR in primary VSMC from aorta of mice with targeted deletion of the EGFR (EGFR(Δ/Δ VSMC)→VSMC(EGFR-/-) and EGFR(Δ/+ VSMC)→VSMC(EGFR+/-)) and the respective littermate controls (EGFR(+/+ VSMC)→VSMC(EGFR+/+)) with respect to survival, pentose phosphate pathway activity, matrix homeostasis, extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation, and Ca(2+) homeostasis. In VSMC(EGFR-/-), epidermal growth factor-induced signaling was abolished; VSMC(EGFR+/-) showed an intermediate phenotype. EGFR deletion enhanced spontaneous cell death, reduced pentose phosphate pathway activity, disturbed cellular matrix homeostasis (collagen III and fibronectin), and abolished epidermal growth factor sensitivity. In VSMC(EGFR-/-) endothelin-1- or α(1)-adrenoceptor-induced ERK1/2 phosphorylation and the fraction of Ca(2+) responders were significantly reduced, whereas responsive cells showed a significantly stronger Ca(2+) signal. Oxidative stress (H(2)O(2)) induced ERK1/2 activation in VSMC(EGFR+/+) and VSMC(EGFR+/-) but not in VSMC(EGFR-/-). The Ca(2+) signal was enhanced in VSMC(EGFR-/-), similar to purinergic stimulation by ATP. CONCLUSIONS In conclusion, EGFR was found to be important for basal VSMC homeostasis and ERK1/2 activation by the tested G-protein-coupled receptors or radical stress. Ca(2+) signaling was modulated by EGFR differentially with respect to the fraction of responders and magnitude of the signal. Thus, EGFR seems to be Janus-faced for VSMC biology.
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Affiliation(s)
- Barbara Schreier
- Julius-Bernstein-Institute of Physiology, University of Halle-Wittenberg, Halle, Germany
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188
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Yu S, Zhang C, Lin CC, Niu Y, Lai KP, Chang HC, Yeh SD, Chang C, Yeh S. Altered prostate epithelial development and IGF-1 signal in mice lacking the androgen receptor in stromal smooth muscle cells. Prostate 2011; 71:517-24. [PMID: 20945497 PMCID: PMC3037429 DOI: 10.1002/pros.21264] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Accepted: 08/11/2010] [Indexed: 11/11/2022]
Abstract
BACKGROUND Androgens and the androgen receptor (AR) play critical roles in the prostate development via mesenchymal-epithelial interactions. Smooth muscle cells (SMC), differentiated from mesenchyme, are one of the basic components of the prostate stroma. However, the roles of smooth muscle AR in prostate development are still obscure. METHODS We established the smooth muscle selective AR knockout (SM-ARKO) mouse model using the Cre-loxP system, and confirmed the ARKO efficiency at RNA, DNA and protein levels. Then, we observed the prostate morphology changes, and determined the epithelial proliferation, apoptosis, and differentiation. We also knocked down the AR in a prostate smooth muscle cell line (PS-1) to confirm the in vivo findings and to probe the mechanism. RESULTS The AR was selectively and efficiently knocked out in the anterior prostates of SM-ARKO mouse. The SM-ARKO prostates have defects with loss of infolding structures, and decrease of epithelial proliferation, but with little change of apoptosis and differentiation. The mechanism studies showed that IGF-1 expression level decreased in the SM-ARKO prostates and AR-knockdown PS-1 cells. The decreased IGF-1 expression might contribute to the defective development of SM-ARKO prostates. CONCLUSIONS The AR in SMCs plays important roles in the prostate development via the regulation of IGF-1 signal.
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Affiliation(s)
- Shengqiang Yu
- George H. Whipple Lab for Cancer Research, Departments of Pathology and Urology, University of Rochester Medical Center, Rochester, New York
- Department of Urology, 1st People’s Hospital, Shanghai Jiaotong University, Shanghai, China
| | - Caixia Zhang
- George H. Whipple Lab for Cancer Research, Departments of Pathology and Urology, University of Rochester Medical Center, Rochester, New York
| | - Chiu-Chun Lin
- George H. Whipple Lab for Cancer Research, Departments of Pathology and Urology, University of Rochester Medical Center, Rochester, New York
| | - Yuanjie Niu
- George H. Whipple Lab for Cancer Research, Departments of Pathology and Urology, University of Rochester Medical Center, Rochester, New York
- Tianjin Institute of Urological Surgery, Tianjin Medical University, Tianjin, China
| | - Kuo-Pao Lai
- George H. Whipple Lab for Cancer Research, Departments of Pathology and Urology, University of Rochester Medical Center, Rochester, New York
| | - Hong-chiang Chang
- George H. Whipple Lab for Cancer Research, Departments of Pathology and Urology, University of Rochester Medical Center, Rochester, New York
| | - Shauh-Der Yeh
- Department of Urology, Taipei Medical University, Taipei, Taiwan 110
| | - Chawnshang Chang
- George H. Whipple Lab for Cancer Research, Departments of Pathology and Urology, University of Rochester Medical Center, Rochester, New York
- Correspondence to: Chawnshang Chang or Shuyuan Yeh, George H. Whipple Lab for Cancer Research or Shuyuan Yeh, PhD, Departments of Pathology and Urology, University of Rochester Medical Center, 601 Elmwood Ave. Box 626, Rochester, New York, 14642. or
| | - Shuyuan Yeh
- George H. Whipple Lab for Cancer Research, Departments of Pathology and Urology, University of Rochester Medical Center, Rochester, New York
- Correspondence to: Chawnshang Chang or Shuyuan Yeh, George H. Whipple Lab for Cancer Research or Shuyuan Yeh, PhD, Departments of Pathology and Urology, University of Rochester Medical Center, 601 Elmwood Ave. Box 626, Rochester, New York, 14642. or
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189
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Conditional deletion of Dicer in vascular smooth muscle cells leads to the developmental delay and embryonic mortality. Biochem Biophys Res Commun 2011; 408:369-74. [PMID: 21371421 DOI: 10.1016/j.bbrc.2011.02.119] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Accepted: 02/24/2011] [Indexed: 01/10/2023]
Abstract
Dicer is a RNAase III enzyme that cleaves double stranded RNA and generates small interfering RNA (siRNA) and microRNA (miRNA). The goal of this study is to examine the role of Dicer and miRNAs in vascular smooth muscle cells (VSMCs). We deleted Dicer in VSMCs of mice, which caused a developmental delay that manifested as early as embryonic day E12.5, leading to embryonic death between E14.5 and E15.5 due to extensive hemorrhage in the liver, brain, and skin. Dicer KO embryos showed dilated blood vessels and a disarray of vascular architecture between E14.5 and E15.5. VSMC proliferation was significantly inhibited in Dicer KOs. The expression of VSMC marker genes were significantly downregulated in Dicer cKO embryos. The vascular structure of the yolk sac and embryo in Dicer KOs was lost to an extent that no blood vessels could be identified after E15.5. Expression of most miRNAs examined was compromised in VSMCs of Dicer KO. Our results indicate that Dicer is required for vascular development and regulates vascular remodeling by modulating VSMC proliferation and differentiation.
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190
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Regulation and therapeutic targeting of peptide-activated receptor guanylyl cyclases. Pharmacol Ther 2010; 130:71-82. [PMID: 21185863 DOI: 10.1016/j.pharmthera.2010.12.005] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Accepted: 12/13/2010] [Indexed: 02/06/2023]
Abstract
Cyclic GMP is a ubiquitous second messenger that regulates a wide array of physiologic processes such as blood pressure, long bone growth, intestinal fluid secretion, phototransduction and lipolysis. Soluble and single-membrane-spanning enzymes called guanylyl cyclases (GC) synthesize cGMP. In humans, the latter group consists of GC-A, GC-B, GC-C, GC-E and GC-F, which are also known as NPR-A, NPR-B, StaR, Ret1-GC and Ret2-GC, respectively. Membrane GCs are activated by peptide ligands such as atrial natriuretic peptide (ANP), B-type natriuretic peptide (BNP), C-type natriuretic peptide (CNP), guanylin, uroguanylin, heat stable enterotoxin and GC-activating proteins. Nesiritide and carperitide are clinically approved peptide-based drugs that activate GC-A. CD-NP is an experimental heart failure drug that primarily activates GC-B but also activates GC-A at high concentrations and is resistant to degradation. Inactivating mutations in GC-B cause acromesomelic dysplasia type Maroteaux dwarfism and chromosomal mutations that increase CNP concentrations are associated with Marfanoid-like skeletal overgrowth. Pump-based CNP infusions increase skeletal growth in a mouse model of the most common type of human dwarfism, which supports CNP/GC-B-based therapies for short stature diseases. Linaclotide is a peptide activator of GC-C that stimulates intestinal motility and is in late-stage clinical trials for the treatment of chronic constipation. This review discusses the discovery of cGMP, guanylyl cyclases, the general characteristics and therapeutic applications of GC-A, GC-B and GC-C, and emphasizes the regulation of transmembrane guanylyl cyclases by phosphorylation and ATP.
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191
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Hofmann JJ, Zovein AC, Koh H, Radtke F, Weinmaster G, Iruela-Arispe ML. Jagged1 in the portal vein mesenchyme regulates intrahepatic bile duct development: insights into Alagille syndrome. Development 2010; 137:4061-72. [PMID: 21062863 DOI: 10.1242/dev.052118] [Citation(s) in RCA: 170] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Mutations in the human Notch ligand jagged 1 (JAG1) result in a multi-system disorder called Alagille syndrome (AGS). AGS is chiefly characterized by a paucity of intrahepatic bile ducts (IHBD), but also includes cardiac, ocular, skeletal, craniofacial and renal defects. The disease penetration and severity of the affected organs can vary significantly and the molecular basis for this broad spectrum of pathology is unclear. Here, we report that Jag1 inactivation in the portal vein mesenchyme (PVM), but not in the endothelium of mice, leads to the hepatic defects associated with AGS. Loss of Jag1 expression in SM22α-positive cells of the PVM leads to defective bile duct development beyond the initial formation of the ductal plate. Cytokeratin 19-positive cells are detected surrounding the portal vein, yet they are unable to form biliary tubes, revealing an instructive role of the vasculature in liver development. These findings uncover the cellular basis for the defining feature of AGS, identify mesenchymal Jag1-dependent and -independent stages of duct development, and provide mechanistic information for the role of Jag1 in IHBD formation.
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Affiliation(s)
- Jennifer J Hofmann
- Molecular Biology Institute, University of California-Los Angeles, Los Angeles, CA 90095, USA
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192
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Feng X, Krebs LT, Gridley T. Patent ductus arteriosus in mice with smooth muscle-specific Jag1 deletion. Development 2010; 137:4191-9. [PMID: 21068062 DOI: 10.1242/dev.052043] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The ductus arteriosus is an arterial vessel that shunts blood flow away from the lungs during fetal life, but normally occludes after birth to establish the adult circulation pattern. Failure of the ductus arteriosus to close after birth is termed patent ductus arteriosus and is one of the most common congenital heart defects. Mice with smooth muscle cell-specific deletion of Jag1, which encodes a Notch ligand, die postnatally from patent ductus arteriosus. These mice exhibit defects in contractile smooth muscle cell differentiation in the vascular wall of the ductus arteriosus and adjacent descending aorta. These defects arise through an inability to propagate the JAG1-Notch signal via lateral induction throughout the width of the vascular wall. Both heterotypic endothelial smooth muscle cell interactions and homotypic vascular smooth muscle cell interactions are required for normal patterning and differentiation of the ductus arteriosus and adjacent descending aorta. This new model for a common congenital heart defect provides novel insights into the genetic programs that underlie ductus arteriosus development and closure.
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Affiliation(s)
- Xuesong Feng
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
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193
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Welsh M, Sharpe RM, Moffat L, Atanassova N, Saunders PTK, Kilter S, Bergh A, Smith LB. Androgen action via testicular arteriole smooth muscle cells is important for Leydig cell function, vasomotion and testicular fluid dynamics. PLoS One 2010; 5:e13632. [PMID: 21049031 PMCID: PMC2964321 DOI: 10.1371/journal.pone.0013632] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Accepted: 09/24/2010] [Indexed: 12/03/2022] Open
Abstract
Regulation of blood flow through the testicular microvasculature by vasomotion is thought to be important for normal testis function as it regulates interstitial fluid (IF) dynamics which is an important intra-testicular transport medium. Androgens control vasomotion, but how they exert these effects remains unclear. One possibility is by signalling via androgen receptors (AR) expressed in testicular arteriole smooth muscle cells. To investigate this and determine the overall importance of this mechanism in testis function, we generated a blood vessel smooth muscle cell-specific AR knockout mouse (SMARKO). Gross reproductive development was normal in SMARKO mice but testis weight was reduced in adulthood compared to control littermates; this reduction was not due to any changes in germ cell volume or to deficits in testosterone, LH or FSH concentrations and did not cause infertility. However, seminiferous tubule lumen volume was reduced in adult SMARKO males while interstitial volume was increased, perhaps indicating altered fluid dynamics; this was associated with compensated Leydig cell failure. Vasomotion was impaired in adult SMARKO males, though overall testis blood flow was normal and there was an increase in the overall blood vessel volume per testis in adult SMARKOs. In conclusion, these results indicate that ablating arteriole smooth muscle AR does not grossly alter spermatogenesis or affect male fertility but does subtly impair Leydig cell function and testicular fluid exchange, possibly by locally regulating microvascular blood flow within the testis.
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Affiliation(s)
- Michelle Welsh
- Medical Research Council Human Reproductive Sciences Unit, Centre for Reproductive Biology, The Queen's Medical Research Institute, Edinburgh, United Kingdom
| | - Richard M. Sharpe
- Medical Research Council Human Reproductive Sciences Unit, Centre for Reproductive Biology, The Queen's Medical Research Institute, Edinburgh, United Kingdom
| | - Lindsey Moffat
- Medical Research Council Human Reproductive Sciences Unit, Centre for Reproductive Biology, The Queen's Medical Research Institute, Edinburgh, United Kingdom
| | - Nina Atanassova
- Institute of Experimental Morphology and Anthropology with Museum, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Philippa T. K. Saunders
- Medical Research Council Human Reproductive Sciences Unit, Centre for Reproductive Biology, The Queen's Medical Research Institute, Edinburgh, United Kingdom
| | - Sigrid Kilter
- Department of Anatomy and Pathology, University of Umeå, Umeå, Sweden
| | - Anders Bergh
- Department of Anatomy and Pathology, University of Umeå, Umeå, Sweden
| | - Lee B. Smith
- Medical Research Council Human Reproductive Sciences Unit, Centre for Reproductive Biology, The Queen's Medical Research Institute, Edinburgh, United Kingdom
- * E-mail:
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194
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Saito Y. Roles of atrial natriuretic peptide and its therapeutic use. J Cardiol 2010; 56:262-70. [PMID: 20884176 DOI: 10.1016/j.jjcc.2010.08.001] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Accepted: 07/14/2010] [Indexed: 10/19/2022]
Abstract
Since the discovery of atrial natriuretic peptide (ANP), there has been tremendous progress in our understanding of the physiologic and pathophysiologic, diagnostic, and therapeutic roles of ANP. The diagnostic application of ANP and brain natriuretic peptide (BNP) has been reviewed by many investigators, and meta-analyses of therapeutic use of BNP were reported from the USA. However, there are few reviews concerning the therapeutic use of ANP in patients with various conditions. Therefore, this review focuses on the recent clinical evidence of ANP in therapeutic use and experimental data that rationally support the therapeutic use of ANP.
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Affiliation(s)
- Yoshihiko Saito
- First Department of Internal Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8522, Japan.
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195
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Verhoeven G, Willems A, Denolet E, Swinnen JV, De Gendt K. Androgens and spermatogenesis: lessons from transgenic mouse models. Philos Trans R Soc Lond B Biol Sci 2010; 365:1537-56. [PMID: 20403868 PMCID: PMC2871915 DOI: 10.1098/rstb.2009.0117] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Transgenic mouse models have contributed considerably to our understanding of the cellular and molecular mechanisms by which androgens control spermatogenesis. Cell-selective ablation of the androgen receptor (AR) in Sertoli cells (SC) results in a complete block in meiosis and unambiguously identifies the SC as the main cellular mediator of the effects of androgens on spermatogenesis. This conclusion is corroborated by similar knockouts in other potential testicular target cells. Mutations resulting in diminished expression of the AR or in alleles with increased length of the CAG repeat mimick specific human forms of disturbed fertility that are not accompanied by defects in male sexual development. Transcriptional profiling studies in mice with cell-selective and general knockouts of the AR, searching for androgen-regulated genes relevant to the control of spermatogenesis, have identified many candidate target genes. However, with the exception of Rhox5, the identified subsets of genes show little overlap. Genes related to tubular restructuring, cell junction dynamics, the cytoskeleton, solute transportation and vitamin A metabolism are prominently present. Further research will be needed to decide which of these genes are physiologically relevant and to identify genes that can be used as diagnostic tools or targets to modulate the effects of androgens in spermatogenesis.
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Affiliation(s)
- Guido Verhoeven
- Department of Experimental Medicine, Laboratory for Experimental Medicine and Endocrinology, Katholieke Universiteit Leuven, Gasthuisberg, Herestraat 49, 3000 Leuven, Belgium.
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196
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Abstract
Cre/loxP recombination enables cellular specificity and, in the case of inducible systems, temporal control of genomic deletions. Here we used a SM22α tamoxifen-inducible Cre line to inactivate β1 integrin in adult smooth muscle. Interestingly, analysis of two distinct β1 loxP transgenic mice revealed vastly different outcomes after β1 integrin deletion. Lethality occurred 4 weeks postinduction in one Cre/loxP line, while no apparent phenotype was seen in the other line. Genetic analysis revealed appropriate DNA excision in both cases; however, differences were found in the degree of protein loss with absolutely no change in protein levels in the model that lacked a phenotype. Seeking to understand protein persistence despite appropriate recombination, we first validated the flox allele using a constitutive Cre line and demonstrated its ability to mediate effective protein inactivation. We then examined the possibility of heterozygous cell selection, protein turnover, and deletion efficiency with no success for explaining the phenotype. Finally, we documented the presence of the Cre-recombination episomal product, which persisted in tissue samples with no protein loss. The product was only noted in cells with low proliferative capacity. These findings highlight the potential for protein expression from the products of Cre-recombinase excised genes, particularly when deletion occurs in low turnover populations.
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197
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198
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Lin FJ, Chen X, Qin J, Hong YK, Tsai MJ, Tsai SY. Direct transcriptional regulation of neuropilin-2 by COUP-TFII modulates multiple steps in murine lymphatic vessel development. J Clin Invest 2010; 120:1694-707. [PMID: 20364082 DOI: 10.1172/jci40101] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2009] [Accepted: 01/20/2010] [Indexed: 01/29/2023] Open
Abstract
The lymphatic system plays a key role in tissue fluid homeostasis. Lymphatic dysfunction contributes to the pathogenesis of many human diseases, including lymphedema and tumor metastasis. However, the mechanisms regulating lymphangiogenesis remain largely unknown. Here, we show that COUP-TFII (also known as Nr2f2), an orphan member of the nuclear receptor superfamily, mediates both developmental and pathological lymphangiogenesis in mice. Conditional ablation of COUP-TFII at an early embryonic stage resulted in failed formation of pre-lymphatic ECs (pre-LECs) and lymphatic vessels. COUP-TFII deficiency at a late developmental stage resulted in loss of LEC identity, gain of blood EC fate, and impaired lymphatic vessel sprouting. siRNA-mediated downregulation of COUP-TFII in cultured primary human LECs demonstrated that the maintenance of lymphatic identity and VEGF-C-induced lymphangiogenic activity, including cell proliferation and migration, are COUP-TFII-dependent and cell-autonomous processes. COUP-TFII enhanced the pro-lymphangiogenic actions of VEGF-C, at least in part by directly stimulating expression of neuropilin-2, a coreceptor for VEGF-C. In addition, COUP-TFII inactivation in a mammary gland mouse tumor model resulted in inhibition of tumor lymphangiogenesis, suggesting that COUP-TFII also regulates neo-lymphangiogenesis in the adult. Thus, COUP-TFII is a critical factor that controls lymphangiogenesis in embryonic development and tumorigenesis in adults.
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Affiliation(s)
- Fu-Jung Lin
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
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199
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Walters KA, Simanainen U, Handelsman DJ. Molecular insights into androgen actions in male and female reproductive function from androgen receptor knockout models. Hum Reprod Update 2010; 16:543-58. [DOI: 10.1093/humupd/dmq003] [Citation(s) in RCA: 119] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
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200
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Tolson KP, Gemelli T, Gautron L, Elmquist JK, Zinn AR, Kublaoui BM. Postnatal Sim1 deficiency causes hyperphagic obesity and reduced Mc4r and oxytocin expression. J Neurosci 2010; 30:3803-12. [PMID: 20220015 PMCID: PMC3285557 DOI: 10.1523/jneurosci.5444-09.2010] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Revised: 12/21/2009] [Accepted: 01/29/2010] [Indexed: 12/27/2022] Open
Abstract
Single-minded 1 (SIM1) mutations are one of the few known causes of nonsyndromic monogenic obesity in both humans and mice. Although the role of Sim1 in the formation of the hypothalamus has been described, its postdevelopmental, physiological functions have not been well established. Here we demonstrate that postnatal CNS deficiency of Sim1 is sufficient to cause hyperphagic obesity. We conditionally deleted Sim1 after birth using CaMKII-Cre (alpha-calcium/calmodulin-dependent protein kinase II-Cre) lines to recombine a floxed Sim1 allele. Conditional Sim1 heterozygotes phenocopied germ line Sim1 heterozygotes, displaying hyperphagic obesity and increased length. We also generated viable conditional Sim1 homozygotes, demonstrating that adult Sim1 expression is not essential for mouse or neuron survival and revealing a dosage-dependent effect of Sim1 on obesity. Using stereological cell counting, we showed that the phenotype of both germ line heterozygotes and conditional Sim1 homozygotes was not attributable to global hypocellularity of the paraventricular nucleus (PVN) of the hypothalamus. We also used retrograde tract tracing to demonstrate that the PVN of germ line heterozygous mice projects normally to the dorsal vagal complex and the median eminence. Finally, we showed that conditional Sim1 homozygotes and germ line Sim1 heterozygotes exhibit a remarkable decrease in hypothalamic oxytocin (Oxt) and PVN melanocortin 4 receptor (Mc4r) mRNA. These results demonstrate that the role of Sim1 in feeding regulation is not limited to formation of the PVN or its projections and that the hyperphagic obesity in Sim1-deficient mice may be attributable to changes in the leptin-melanocortin-oxytocin pathway.
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MESH Headings
- Animals
- Animals, Newborn
- Basic Helix-Loop-Helix Transcription Factors/deficiency
- Basic Helix-Loop-Helix Transcription Factors/genetics
- Eating/genetics
- Female
- Gene Expression Regulation, Developmental
- Gene Silencing
- Hyperphagia/genetics
- Hyperphagia/metabolism
- Hyperphagia/pathology
- Hyperphagia/physiopathology
- Hypothalamus/metabolism
- Hypothalamus/pathology
- Hypothalamus/physiopathology
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Obesity/genetics
- Obesity/metabolism
- Obesity/pathology
- Obesity/physiopathology
- Oxytocin/antagonists & inhibitors
- Oxytocin/biosynthesis
- Oxytocin/genetics
- Paraventricular Hypothalamic Nucleus/metabolism
- Paraventricular Hypothalamic Nucleus/pathology
- Paraventricular Hypothalamic Nucleus/physiopathology
- RNA, Messenger/antagonists & inhibitors
- RNA, Messenger/biosynthesis
- Receptor, Melanocortin, Type 4/antagonists & inhibitors
- Receptor, Melanocortin, Type 4/biosynthesis
- Receptor, Melanocortin, Type 4/genetics
- Repressor Proteins/deficiency
- Repressor Proteins/genetics
- Reproducibility of Results
- Signal Transduction/genetics
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Affiliation(s)
| | | | - Laurent Gautron
- Division of Hypothalamic Research
- Departments of Internal Medicine
- Pharmacology, and
- Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas 75390, and
| | - Joel K. Elmquist
- Division of Hypothalamic Research
- Departments of Internal Medicine
- Pharmacology, and
- Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas 75390, and
| | - Andrew R. Zinn
- McDermott Center for Human Growth and Development
- Departments of Internal Medicine
| | - Bassil M. Kublaoui
- Division of Endocrinology and Diabetes, Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104
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