bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 516: Knockdown of the Hypertension Associated Gene NOSTRIN Alters Glomerular Barrier Function in Zebrafish (Danio rerio)
Authors: Kirsch Torsten , Kaufeld Jessica , Korstanje Ron , Hentschel Dirk , Haller Hermann , Schiffer Mario 
Published: July 2021

The bioavailability of nitric oxide (NO) has been associated with the development and progression of vascular and renal disease. NOSTRIN (for eNOS Traffic Inducer) has primarily been recognized as one important regulator of eNOS, the prime source of NO in the cardiovascular system, with a possible role in the pathogenesis of pre-eclampsia and the development of increased intrahepatic resistance in liver disease.
Here, we identified NOSTRIN in the center of a QTL-overlap region in rat and human trait loci that are associated with hypertension. Glomerular NOSTRIN expression is detectable in podocytes in human and rat glomeruli and podocytic NOSTRIN expression is diminished in hypertensive kidney disease. We show that knockdown of NOSTRIN alters the glomerular filtration barrier function in larval zebrafish, inducing proteinuria and leading to ultrastructural morphological changes on the endothelial as well as epithelial side and the GBM of the glomerular capillary loop. We also demonstrate that NOSTRIN interacts with proteins associated with the podocyte slit membrane. We conclude that NOSTRIN expression is an important factor for the integrity of the glomerular filtration barrier. Disease related alteration of NOSTRIN expression may not only affect the vascular endothelium and therefore contribute to endothelial cell dysfunction but may also contribute to the development of podocyte disease and proteinuria.
Abstract 394: Angiotensin II Mediated Increase in Hypertension and Cardiac Hypertrophy in MyD88 Knockout Mice
Authors: Singh Madhu V , Harwani Sailesh C , Whiteis Carol A , Cicha Michael Z , Chapleau Mark W , Abboud Francois M 
Published: July 2021

Toll-like receptors (TLR) are a class of pattern-recognizing receptors (PRR) that play a central role in the innate immune response during infection and sterile injury. MyD88 is an adapter protein that mediates the majority of TLR responses. Since inflammation is a coexisting condition in several cardiovascular diseases, TLRs are thought to play a major role in these conditions. We have previously shown that indeed post-MI survival was significantly improved and cardiac fibrosis and hypertrophy were reduced in MyD88-/- mice (Singh et al. 2012. JMCC). In this study we tested whether angiotensin II (AngII) hypertension and cardiac hypertrophy depended on TLR signaling pathways mediated by MyD88. Male MyD88-/- mice and C57BL/6 mice of 10 to 12 weeks of age were subcutaneously implanted with osmotic minipumps (Alzet) eluting saline or AngII (Sigma, 733 ng/kg/min). Tailcuff pressures were measured with BP2000 (Visitech Systems). Mice were sacrificed after 3 weeks of AngII infusion and hearts were collected for weighing and gene expression analyses. In control WT mice, mean arterial pressure (MAP) remained near baseline levels during the first week of infusion averaging 71± 2 mm Hg and then increased to an average of 100 ± 3 mm Hg and 102 ± 2 mm Hg during the 2nd and 3rd weeks of infusions, respectively. In MyD88-/- mice, MAP increased from a baseline of 84 ± 3 to a high of 120 ± 7 mm Hg during the first week and then declined to 109 ± 6 and 91 ± 9 mm Hg during the 2nd and 3rd weeks. The heart weight to body weight ratios (HW/BW x 1000) after 3 weeks of AngII infusion were not significantly different between WT (5.23 ± 0.15) and MyD88-/- (4.76 ± 0.16). Increases in cardiac hypertrophic marker gene Acta1 were up 4-fold in both WT and MyD88-/- mice, and increases in proinflammatory TNF-alpha, IL-1β, and Nox4 were seen in both genotypes, but the increase in TNF-alpha was significantly greater in MyD88-/- mice.
We conclude that unlike post- MI cardiac hypertrophy, the AngII cardiac hypertrophy is not MyD88 -dependent, yet the delayed Ang II pressor response is abrogated in the absence of MyD88. The delayed pressor response to AngII infusion is likely dependent on the immune system.
Abstract 452: The Degree of Nephron Deficit is a Determinant of the Cardiovascular and Renal Risks Associated With a Reduced Nephron Endowment
Authors: Kett Michelle M , Makuei Leek , Cai Xiaochu , Brown Russell D 
Published: July 2021

A reduced nephron endowment is associated with an increased sensitivity to hypertensive stimuli. We examined whether nephron endowment, and the degree of nephron deficit, impacts on the blood pressure and renal response to chronic angiotensin II (AngII) infusion. To address this aim we used the GDNF heterozygous mouse that, despite the same genotype, produces two distinct levels of nephron deficit due to the role of GDNF in both the initiation of kidney development and induction of nephron formation. GDNF het mice are born with either 2 small kidneys and a 30% nephron deficit (Het2K), or a single small kidney (Het1K) and a 65% nephron deficit compared to wild-type littermates (WT).
Sixteen week old male GDNF WT (n=9), Het2K (n=5) and Het1K (n=7) mice were implanted with radiotelemetry probes and baseline pressures recorded. Mice were administered enalapril (10mg/kg/day, drinking water) alone for 3 days, then concomitant with an AngII infusion (600ng/kg/min; s.c. osmotic minipump) for a further 21 days. 24hr albumin and urine excretion were assessed at baseline and at the end of the 21 days of blood pressure recording.
Baseline MAP was not different between WT, Het2K and Het1K groups (98.3±1.3, 97.1±1.8, 100.9±1.9mmHg respectively). Enalapril treatment led to a similar fall in MAP of 23mmHg in the 3 groups before the commencement of AngII infusion. AngII led to an immediate rise in MAP in all groups. At the end of the 21day infusion period, MAP of WT and Het2K mice were similar (122±3.3, 120.5±6.1mmHg), but MAP of Het1K mice (139.7±3.6mmHg; P<0.01) was significantly elevated over WT mice. Albumin excretion was not different between the groups at baseline, and AngII infusion did not significantly increase albumin excretion in WT or Het2K mice. However albumin excretion in Het1K mice increased 15 fold (4.86±1.56 to 76.05±30.3ug/24hr; P<0.001). Urine excretion also significantly increased in the Het1K (1.59±1.5 to 3.7±0.59ml/24h; P<0.001) in response to Angiotensin II, though WT and Het2k mice were not affected.
AngII infusion in Het1K, but not Het2k mice, led to significant exacerbation of hypertension and albuminuria. Our data suggests that the degree of nephron deficit is an important determinant of the risks associated with a reduced nephron endowment.
Abstract 463: Transregulation and Plasma Membrane Recruitment of the Dopamine-1 (D1R) and Angiotensin Type 2 (AT2R) Receptors in Human Renal Proximal Tubule Cells (RPTC)
Authors: Opper Phuong B , Gildea John J , Felder Robin A 
Published: July 2021

Both the D1R and AT2R are key natriuretic receptors in that stimulation by dopamine agonists or AT2R agonist angiotensin III (AngIII) increases cAMP and cGMP, respectively, causing inhibition of sodium reabsorption. The interdependence of D1R and AT2R stimulation on receptor translocation has not been studied. We utilized normally coupled RPTC (nRPTC) and RPTC with defective D1R coupling to adenylyl cyclase (uRPTC). A 1 hr addition of the cell permeable cyclic nucleotide analogs 8Br-cGMP (1 mM) or 8Br-cAMP (1 mM) caused a similar recruitment of both D1R and AT2R, as measured by cell surface biotinylation and western blotting (see table below).
Flow cytometry confirmed these results using fluorescently labeled extracellular epitope-specific D1R and AT2R antibodies. When 8Br-cAMP and 8Br-cGMP were added together, no added effects were seen. AngIII-alone increased plasma membrane recruitment of D1R (1.23±0.04 fold, n=6, p<0.05, VEH=0.63) and AT2R (1.65±0.10 fold, n=6, p<0.05, VEH=0.69) in nRPTC but not in uRPTC. The nRPTC response was completely blocked by the AT2R specific antagonist PD123319 or the D1R antagonist LE300. Inhibition of either PKA with adenosine-3’, 5’-cyclic monophosphorothioate Rp-Isomer (100 μM) or PKG with 8-(4-chlorophenylthio) guanosine-3’, 5’ -cyclic monophosphorothioate Rp-isomer (10 μM) completely inhibited the cell surface recruitment of both D1R and AT2R when stimulated with 8Br-cAMP or 8Br-cGMP, respectively.
In conclusion, we found a novel AngIII-interdependent AT2R and D1R cell surface recruitment in human nRPTC cells. Furthermore, defects in this pathway in uRPTC can be bypassed by incubating the cells with either 8Br-cAMP or 8Br-cGMP.
Abstract 540: Increased Intrarenal CGRP Release From Afferent Renal Nerves Is Accompanied By Decreased Afferent Electric Activity
Authors: Ditting Tilmann , Rodionova Kristina , Heinlein Sonja , Fischer Michael , Reeh Peter , Tiegs Gisa , Ott Christian , Schmieder Roland E , Freisinger Wolfgang , Veelken Roland 
Published: July 2021

Afferent peptidergic renal nerves exhibit a dual function. They influence intrarenal immunological processes by releasing peptides like CGRP and control central sympathetic outflow via afferent electrical activity. The former seems to be important in renal inflammation whereas the modulation of sympathetic outflow by afferent electrical activity is not fully understood. Hence, we wanted to test the hypothesis that augmented effects of CGRP in renal inflammation occur with increased afferent renal nerve activity.
As inflammatory model, normotensive renal inflammation (RI) was induced by i.v. injection of 1.75 mg/kg BW OX-7 antibody to rats. Animals were investigated neurophysiologically and pathomorphologically using standard techniques at day 6 after induction of RI.
There was no increase in blood pressure (BP) in RI animals, hence confounding effects of BP were unlikely. RI rats exhibited albuminuria (61±6 μg/24h), infiltration of macrophages in the interstitium (26 ± 4 cells/high-power field) and glomeruli (3.7±0.6 cells/glomerular cross-section). Pretreatment with the CGRP antagonist rCGRP 8-37 (Tocris Bioscience 15nmol/kg) significantly reduced proteinuria and macrophage infiltration suggesting increased activity of CGRP in RI. In an in-vitro assay, renal tissue of rats with RI exhibited increased release of CGRP (14 ± 3 pg/ml vs. controls 6.8 ± 2.8 pg/ml; p<0.05, n=8). RI tissue from renally denervated rats showed no detectable levels of CGRP. These results suggested CGRP release from renal nerves at a higher rate in RI. Directly recorded afferent renal nerve activity (ARNA; spikes/sec) was unexpectedly lower in RI compared to controls (8.0 ± 1.8 vs. 27.4 ± 4.1 Hz*,n=6, p<0.05). On the other hand, the burst-frequency of directly recorded renal sympathetic nerve activity (RSNA) in RI was significantly higher than in controls (14.7 ± 0.9 vs. 11.5 ± 0.9 bursts/sec*; n=6, *p<0.05).
In contrast to our assumption increased release of neurogenic CGRP aggravating renal inflammation occurred with decreased ARNA. Increased RSNA pointed to a reduced tonic inhibition by ARNA. In hypertension, the later mechanism might worsen sympathetic dysregulation and renal damage.
Abstract 022: Evidence for AT2-receptor-MAS Dimerisation from Fluorescence Resonance Energy Transfer (FRET) Imaging and Fluorescence Cross Correlation Spectroscopy (FCCS)
Authors: Villela Daniel C , Teichmann Anke , Kirsch Sebastian , Mardahl Maibritt , Münter Lisa M , Lucht Kristin , Alenina Natalia , Unger Thomas , Bader Michael , Schülein Raph , Santos Robson A , Steckelings Ulrike M 
Published: July 2021

The angiotensin AT2-receptor (AT2R) and the receptor MAS share a strinkingly similar spectrum of signaling mechanisms and protective, physiological actions. Furthermore, cross-inhibition by the respective receptor antagonists has been observed. Therefore we hypothesised that a physical interaction between these two receptors may exist.
HEK-293 cells were transfected with vectors encoding MAS or AT2R fused in the C-terminus with the fluorophores CFP or YFP for FRET and GFP or mCherry for FCCS.
FRET with photobleaching was used to detect, whether MAS and AT2R are localised in very close proximity (1-10nm) in cell membranes thus indicating dimerisation. FCCS was used to follow simultaneously occurring fluctuations in fluorescence intensity of both labeled molecules.
Several controls were applied such as co-transfection of equal amounts of fused and non-fused MAS/AT2R expression vectors for competition, co-tranfection of coding and uncoding pcDNA vectors or co-transfection with an unrelated transmembrane receptor.
Experiments were conducted under baseline conditions and in cells treated with AT2R/MAS agonists and antagonists
Significant FRET efficiency of 10.8±0.8% was measured for AT2-YFP/MAS-CFP strongly indicating heterodimerisation. FRET efficiency was not altered by AT2R or MAS agonists or antagonists. Non-fluorescent MAS and AT2R competed with fluorescent receptors as indicated by a 50% reduction in FRET efficiency (6.0±0.6%), while empty vectors did not compete (9.6±0.6%). No FRET efficiency was observed with an unrelated transmembrane receptor (0.44±1.44%) indicating specificity of receptor interactions. Both, MAS and AT2R also formed homodimers (7.4±0.8% for MAS, 9.2±0.8% for AT2R). Hetero- and homodimerisations were absent if amino acid C35 of the AT2R was mutated (3,9 ± 1,2%).
FCCS corroborated the FRET results and revealed a significantly enhanced cross correlation in cells tranfected with fluorophore-tagged MAS/AT2R when compared to vectors only expressing the fluorophores (8.5±3% vs 11.1±4%; p<0.0001).
Our data strongly suggest that MAS and the AT2R form homo- and heterodimers. Studies to investigate the physiological relevance of MAS/AT2R dimerisation are currently being conducted.
Abstract 213: Fat Tissue specific Adipose Triglyceride Lipase as a major determinant for the development of pressure overload-induced heart failure
Authors: Salatzki Janek , Brix Sarah , Ban Zsofia , Fliegner Daniela , Benz Verena , Kershaw Erin E , Kintscher Ulrich , Foryst-Ludwig Anna 
Published: July 2021

Introduction:
Myocardial metabolism undergoes change in response to pathological cardiac hypertrophy (PH), characterized by increased reliance on glucose oxidation, decreased free fatty acid (FFA) oxidation and a loss of metabolic flexibility. Cardiac metabolism is influenced by other organs such as adipose tissue. Hence, we aimed to investigate the effect of Adipose Triglyceride Lipase (ATGL) in adipose tissue on the development of PH and heart failure (HF) in a pressure overload-induced cardiac hypertrophy model in mice.

Methods:
Male adipose tissue specific ATGL-knock out (atATGL-KO) and wild type mice (WT) underwent sham surgery (sham) or transverse aortic constriction (TAC). After 11 weeks, mice were sacrificed and organs were harvested.

We performed echocardiography one week before and 11 weeks after surgery. Left ventricular mass (LVM), left ventricular mass/tibia length (LVM/TL) and ejection fraction (EF) were calculated. Beta-myosin heavy chain (β-MyHC) was measured in RNA of hearts. Insulin resistance was assessed by an intraperitoneal glucose tolerance test (GTT) and an insulin tolerance test (ITT). FFAs were measured in serum in total.

Results:
LVM and LVM/TL in WT was significantly higher compared to atATGL-KO after TAC (LVM/TL [mg/mm] WT-TAC: 18,0±2,2; atATGL-KO-TAC: 13,1±2,3; p<0,01). The higher increase of LVM in WT was associated with a larger left ventricle internal diameter. Reduction of EF was significantly more pronounced in WT compared to atATGL-KO ([%] WT: 28,81±6,9 atATGL-KO: 42,39±4,5; p<0,01).

Beta-MyHC, a marker for PH, was markedly higher in WT-TAC than in atATGL-KO-TAC (WT-TAC: 11,3±3,6; atATGL-KO-TAC: 1.9±0,6; p<0,01).
While WT-TAC showed higher Serum FFA-levels than atATGL-KO-TAC ([mmol/l] WT-TAC: 0,97±0,086; atATGL-KO-TAC: 0,49±0,032; p<0,001), GTT and ITT revealed a higher insulin sensitivity in atATGL-KO-TAC compared to WT-TAC.

Conclusion:
The present study demonstrates that atATGL is a crucial determinant for the development of pressure overload-induced PH and HI. The lack of ATGL in adipose tissue, the associated reduction of fatty acid release in the circulation and subsequent switches in cardiac energy substrates from free fatty acids to glucose are potential underlying mechanisms of this process.
Abstract 348: Inhibition Of Phosphodiesterase 5 Attenuates Angiotensin II-dependent Hypertension And Renal Vascular Dysfunction In C57bl/6 Mice But Not In Enos-Ko Mice
Authors: Thieme Manuel , Sivritas Sema , Potthoff Sebastian A , Mergia Evanthia , Rump Lars C , Stegbauer Johannes 
Published: July 2021

The kidney plays an outstanding role in the blood pressure (BP) regulation. The renal vasoconstrictor response to angiotensin (Ang) II is balanced by the NO/cGMP-signalling cascade. Ang II causes hypertension and vascular dysfunction by reducing cGMP sensitivity. Ang II is able to increase cGMP degradation by activating phosphodiesterase (PDE)1 and PDE5. The aim of the present study was to identify the predominant PDE subunit regulating renal blood flow (RBF) and vascular tone during hypertension. Therefore, we tested in vivo effects of acute PDE1 (vinpocetine) and PDE5 (sildenafil) inhibition at baseline and during acute Ang II infusion (200ng/kg/min). Furthermore, we examined the impact of PDE-inhibition on Ang II dependent hypertension (500ng/kg/min; 14 days) and on renal vascular function in the isolated perfused kidney.
Acute vinpocetine administration (0.8-800μg/kg BW) showed almost no effect on systemic BP and RBF at baseline and during acute Ang II infusion. In contrast, sildenafil (0.8-800μg/kg BW) significantly decreased BP under baseline conditions. During acute Ang II infusion, BP reduction and RBF increase induced by sildenafil was even more pronounced suggesting a pivotal role of the PDE5 in the regulation of renal vascular tone. Based on these results, we tested whether inhibition of the PDE5 protects from hypertension and vascular dysfunction. Indeed, chronic sildenafil treatment significantly attenuated Ang II dependent hypertension in C57BL/6 (vehicle vs. sil: 156±4 vs. 139±7; p<0.05). Moreover, Sildenafil treatment significantly improved NO-dependent vasorelaxation in kidneys of Ang II- treated C57BL/6. To confirm that PDE5 is activated by an increased NO/cGMP signaling, we used eNOS-KO mice, a model known for decreased NO dependent cGMP generation. In eNOS-KO mice, sildenafil failed to reduce Ang II dependent hypertension (172,4 ± 4,3 mmHg vs. 166,1 ± 3,8 mmHg, p=0,2753) and did not improve vascular dysfunction in Ang II treated kidneys.
In summary, the PDE5 is the predominant PDE regulating RBF. Inhibition of PDE5 by sildenafil ameliorates chronic Ang II dependent hypertension and improves vascular dysfunction. This study reveals new evidence for the pivotal role of PDE5 in the pathogenesis of AngII-induced hypertension.
Abstract 484: The Vasorelaxing / No Release Effect Of Angiotensin-(1-9) Is Independent Of At2, Mas Or Mrgd Receptors
Authors: Resende Gabriel S , Silva Neyva , Villela Daniel C , Santos Robson A 
Published: July 2021

Angiotensin-(1-9) is a nonapeptide formed by the hydrolysis of angiotensin I by ACE2 that seems to counter-regulate the classical RAS axis. Recent studies suggest that Ang-(1-9) acts via AT2 receptors (AT2R), however the pharmacological tool used to asses this ang-(1-9) /AT2R mediated interaction, is the AT2R antagonist, PD123319, that appears to have a great deal of inespecificity . Two other candidates for the ligation of Ang-(1-9), that have protective effects similar to the AT2R, are the MAS and the recently described MrgD receptor. Thus, in this study we addressed if Ang-(1-9) could be a ligand for AT2, MAS or MrgD receptors using aortic rings taken from AT2 and Mas knockout mice and AT2R or MrgD-transfected CHO cells.

Materials and methods:
The endothelium-dependent vasodilatory response to Ang-(1-9) was tested in aortic rings taken from Wild-Type, AT2KO and MASKO mice and Sprague-Dawley rats, pre-contracted with phenylephrine (0.1 umoles/L). NO release from AT2R or MrgD stable transfected CHO cells was evaluated using the NO indicator 4-amino-5 methylamino-2, 7 difluorofluorescein diacetate (DAF-FM) after Ang-(1-9) stimulation.

Results:
In aortic rings from SD rats Ang-(1-9) produced a dose-related relaxation (Emax= 15 ± 2.6) which was not modified by A-779 (Emax=12.9 ± 1.9) , the Mas/MrgD antagonist D-Pro7-Ang-(1-7) (Emax= 15.6 ± 1.7); or by PD123319 (Emax= 22.7 ± 5.4) . In aortic rings taken from MasKO there was a minor attenuation of the Ang-(1-9) vasorelaxant effect when compared to the WT, but the response was not abolished. No difference between AT2KO and WT mice was observed regarding the vasorelaxation produced by Ang-(1-9) (Emax= 20.7±2.4 and 20.9 ± 1.3 respectively). Moreover, the vasorelaxing effect of Ang-(1-9) was not affected by the association of PD123319 and D-Pro7-Ang-(1-7).

In addition, the nonapeptide did not stimulate NO production in AT2R-stably transfected CHO cells or MrgD stably transfected cells.
Taken together these results suggest that the vasorelaxation produced by Ang-(1-9) in rodent aortic rings is independent of Mas , AT2R or MrgD receptors.
Abstract P094: Vasopressin Infusion in Mice During Pregnancy Results in Immune Alterations Consistent with Human Preeclampsia
Authors: Scroggins Sabrina M , Santillan Donna A , Pearson Nicole A , Sangren Jeremy A , Min James Y , Devor Eric J , Pierce Gary L , Leslie Kimberly K , Grobe Justin L , Santillan Mark K 
Published: July 2021

The immediate and long-term maternal and fetal health complications of preeclampsia (PreE) have been linked to an aberrant T helper immune response and pro-inflammatory cytokine profile. AVP secretion is both stimulated by and stimulates pro-inflammatory cytokine secretion and activation of lymphocytes. Our AVP infusion mouse model of PreE closely replicates human PreE. The objective of this study was to investigate if AVP infusion induces the maternal-fetal immune alterations in PreE.
Immune responses were evaluated in wild-type C57BL/6 female mice chronically infused with AVP (24 ng/hr or saline s.c.) throughout pregnancy. By flow cytometry, we observed an increase in the frequency of IL-17 (1.2% vs. 2.6%, p<0.05), TNFα (0.9% vs. 1.6%, p<0.0001), and IFNγ (1.8% vs. 3.4%, p<0.05) expressing T cells in AVP dams. An increase in the frequency of IL-12 producing cells (1.0% vs. 2.4%, p<0.05) and elevated expression of co-stimulatory molecules on dendritic cells (DCs) from AVP dams suggested enhanced DC function. The maternal plasma revealed a significant reduction in IL-17 (7.1e+6 vs. 3.4e+5 ng/g, p<0.05) and IL-6 (3.4e+5 vs. 0.0 ng/g, p<0.01) production in AVP dams by ELISA as seen in human PreE. Pro-inflammatory TNFα was also significantly decreased in the maternal kidney of AVP dams (2.3e+9 vs. 1.3e+9 ng/g, p<0.05). IL-4 production was significantly reduced in the maternal kidney of AVP dams (5.7e+7 vs. 3.4+7 ng/g, p<0.05) suggesting a blunted Th2 response as seen in human PreE. AVP infusion did not result in alterations of cytokine production in the maternal liver, or fetal liver and kidney. Interestingly, IL-17 production was increased in the amniotic fluid (3.0e+6 vs. 1.3e+7 ng/g, p<0.05) and lower in the placenta (2.5e+7 vs. 1.3e+7 ng/g, p<0.0001) of AVP dams. IL-4 production was decreased in both the amniotic fluid (4.5e+5 vs. 2.0e+5 ng/g, p<0.05) and placenta (3.1e+6 vs. 2.0e+6 ng/g, p<0.05) of AVP dams again suggesting a lower Th2 response.
These data support our hypothesis that AVP induces maternal-fetal immune alterations consistent with human PreE. Ongoing experiments are aimed at identifying the lymphocytes and cytokines involved as well as local vs. systemic immune dysfunction induced by AVP in pregnancy.