TY - JOUR A1 - Tauscher, Sabine A1 - Nakagawa, Hitoshi A1 - Völker, Katharina A1 - Werner, Franziska A1 - Krebes, Lisa A1 - Potapenko, Tamara A1 - Doose, Sören A1 - Birkenfeld, Andreas L. A1 - Baba, Hideo A. A1 - Kuhn, Michaela T1 - β Cell-specific deletion of guanylyl cyclase A, the receptor for atrial natriuretic peptide, accelerates obesity-induced glucose intolerance in mice JF - Cardiovascular Diabetology N2 - Background: The cardiac hormones atrial (ANP) and B-type natriuretic peptides (BNP) moderate arterial blood pressure and improve energy metabolism as well as insulin sensitivity via their shared cGMP-producing guanylyl cyclase-A (GC-A) receptor. Obesity is associated with impaired NP/GC-A/cGMP signaling, which possibly contributes to the development of type 2 diabetes and its cardiometabolic complications. In vitro, synthetic ANP, via GC-A, stimulates glucose-dependent insulin release from cultured pancreatic islets and β-cell proliferation. However, the relevance for systemic glucose homeostasis in vivo is not known. To dissect whether the endogenous cardiac hormones modulate the secretory function and/or proliferation of β-cells under (patho)physiological conditions in vivo, here we generated a novel genetic mouse model with selective disruption of the GC-A receptor in β-cells. Methods: Mice with a floxed GC-A gene were bred to Rip-CreTG mice, thereby deleting GC-A selectively in β-cells (β GC-A KO). Weight gain, glucose tolerance, insulin sensitivity, and glucose-stimulated insulin secretion were monitored in normal diet (ND)- and high-fat diet (HFD)-fed mice. β-cell size and number were measured by immunofluorescence-based islet morphometry. Results: In vitro, the insulinotropic and proliferative actions of ANP were abolished in islets isolated from β GC-A KO mice. Concordantly, in vivo, infusion of BNP mildly enhanced baseline plasma insulin levels and glucose-induced insulin secretion in control mice. This effect of exogenous BNP was abolished in β GC-A KO mice, corroborating the efficient inactivation of the GC-A receptor in β-cells. Despite this under physiological, ND conditions, fasted and fed insulin levels, glucose-induced insulin secretion, glucose tolerance and β-cell morphology were similar in β GC-A KO mice and control littermates. However, HFD-fed β GC-A KO animals had accelerated glucose intolerance and diminished adaptative β-cell proliferation. Conclusions: Our studies of β GC-A KO mice demonstrate that the cardiac hormones ANP and BNP do not modulate β-cell's growth and secretory functions under physiological, normal dietary conditions. However, endogenous NP/GC-A signaling improves the initial adaptative response of β-cells to HFD-induced obesity. Impaired β-cell NP/GC-A signaling in obese individuals might contribute to the development of type 2 diabetes. KW - cylic GMP KW - guanylyl cyclase-A KW - insulin KW - natriuretic peptides KW - obesity KW - β-cells Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-176322 VL - 17 IS - 103 ER - TY - JOUR A1 - Müller, Stefanie H. A1 - Girard, Simon L. A1 - Hopfner, Franziska A1 - Merner, Nancy D. A1 - Bourassa, Cynthia V. A1 - Lorenz, Delia A1 - Clark, Lorraine N. A1 - Tittmann, Lukas A1 - Soto-Ortolaza, Alexandra I. A1 - Klebe, Stephan A1 - Hallett, Mark A1 - Schneider, Susanne A. A1 - Hodgkinson, Colin A. A1 - Lieb, Wolfgang A1 - Wszolek, Zbigniew K. A1 - Pendziwiat, Manuela A1 - Lorenzo-Betancor, Oswaldo A1 - Poewe, Werner A1 - Ortega-Cubero, Sara A1 - Seppi, Klaus A1 - Rajput, Alex A1 - Hussl, Anna A1 - Rajput, Ali H. A1 - Berg, Daniela A1 - Dion, Patrick A. A1 - Wurster, Isabel A1 - Shulman, Joshua M. A1 - Srulijes, Karin A1 - Haubenberger, Dietrich A1 - Pastor, Pau A1 - Vilariño-Güell, Carles A1 - Postuma, Ronald B. A1 - Bernard, Geneviève A1 - Ladwig, Karl-Heinz A1 - Dupré, Nicolas A1 - Jankovic, Joseph A1 - Strauch, Konstantin A1 - Panisset, Michel A1 - Winkelmann, Juliane A1 - Testa, Claudia M. A1 - Reischl, Eva A1 - Zeuner, Kirsten E. A1 - Ross, Owen A. A1 - Arzberger, Thomas A1 - Chouinard, Sylvain A1 - Deuschl, Günther A1 - Louis, Elan D. A1 - Kuhlenbäumer, Gregor A1 - Rouleau, Guy A. T1 - Genome-wide association study in essential tremor identifies three new loci JF - Brain N2 - We conducted a genome-wide association study of essential tremor, a common movement disorder characterized mainly by a postural and kinetic tremor of the upper extremities. Twin and family history studies show a high heritability for essential tremor. The molecular genetic determinants of essential tremor are unknown. We included 2807 patients and 6441 controls of European descent in our two-stage genome-wide association study. The 59 most significantly disease-associated markers of the discovery stage were genotyped in the replication stage. After Bonferroni correction two markers, one (rs10937625) located in the serine/threonine kinase STK32B and one (rs17590046) in the transcriptional coactivator PPARGC1A were associated with essential tremor. Three markers (rs12764057, rs10822974, rs7903491) in the cell-adhesion molecule CTNNA3 were significant in the combined analysis of both stages. The expression of STK32B was increased in the cerebellar cortex of patients and expression quantitative trait loci database mining showed association between the protective minor allele of rs10937625 and reduced expression in cerebellar cortex. We found no expression differences related to disease status or marker genotype for the other two genes. Replication of two lead single nucleotide polymorphisms of previous small genome-wide association studies (rs3794087 in SLC1A2, rs9652490 in LINGO1) did not confirm the association with essential tremor. KW - quality-control KW - disease KW - tool KW - movement disorders KW - genome-wide association study KW - tremor KW - genetics KW - essential tremor Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-186541 VL - 139 ER - TY - JOUR A1 - Werner, Franziska A1 - Kojonazarov, Baktybek A1 - Gaßner, Birgit A1 - Abeßer, Marco A1 - Schuh, Kai A1 - Völker, Katharina A1 - Baba, Hideo A. A1 - Dahal, Bhola K. A1 - Schermuly, Ralph T. A1 - Kuhn, Michaela T1 - Endothelial actions of atrial natriuretic peptide prevent pulmonary hypertension in mice JF - Basic Research in Cardiology N2 - The cardiac hormone atrial natriuretic peptide (ANP) regulates systemic and pulmonary arterial blood pressure by activation of its cyclic GMP-producing guanylyl cyclase-A (GC-A) receptor. In the lung, these hypotensive effects were mainly attributed to smooth muscle-mediated vasodilatation. It is unknown whether pulmonary endothelial cells participate in the homeostatic actions of ANP. Therefore, we analyzed GC-A/cGMP signalling in lung endothelial cells and the cause and functional impact of lung endothelial GC-A dysfunction. Western blot and cGMP determinations showed that cultured human and murine pulmonary endothelial cells exhibit prominent GC-A expression and activity which were markedly blunted by hypoxia, a condition known to trigger pulmonary hypertension (PH). To elucidate the consequences of impaired endothelial ANP signalling, we studied mice with genetic endothelial cell-restricted ablation of the GC-A receptor (EC GC-A KO). Notably, EC GC-A KO mice exhibit PH already under resting, normoxic conditions, with enhanced muscularization of small arteries and perivascular infiltration of inflammatory cells. These alterations were aggravated on exposure of mice to chronic hypoxia. Lung endothelial GC-A dysfunction was associated with enhanced expression of angiotensin converting enzyme (ACE) and increased pulmonary levels of Angiotensin II. Angiotensin II/AT(1)-blockade with losartan reversed pulmonary vascular remodelling and perivascular inflammation of EC GC-A KO mice, and prevented their increment by chronic hypoxia. This experimental study indicates that endothelial effects of ANP are critical to prevent pulmonary vascular remodelling and PH. Chronic endothelial ANP/GC-A dysfunction, e.g. provoked by hypoxia, is associated with activation of the ACE-angiotensin pathway in the lung and PH. KW - Atrial natriuretic peptide KW - Endothelium KW - Guanylyl cyclase-A KW - Cyclic GMP KW - Pulmonary hypertension Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-190664 VL - 111 IS - 2 ER -