bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mitochondria influence NMDA‐induced calcium dynamics in hypothalamic magnocellular neurosecretary cells (686.28)
Authors: Potapenko Evgeniy , Javier Stern 
Published: June 2021

The spatiotemporal characteristics of NMDA receptor‐mediated changes in intracellular calcium ([Ca2+]i) (NMDAR‐[Ca2+]i) is critical in determining the strength of NMDA effects on neuronal excitability. Here we investigated the role mitochondria in shaping NMDAR‐[Ca2+]i dynamics. We activated NMDARs before and after the mitochondrial uncoupler CCCP (10µM for 10 sec), which prevents [Ca2+]i uptake by disruption of the proton gradient across the mitochondrial inner membrane. In both, identified and non‐identified eGFP‐VP SON neurons, focal application of NMDA (10µM for 1 sec) following CCCP resulted in a significantly larger and slower Δ[Ca2+]i response both in soma and dendrites, and a more robust membrane depolarization and firing discharge compared to the control application. Conversely, a similar underlying NMDAR‐mediated current (INMDA) was observed. Direct depolarization of SON neurons by current injection (0.15 nA for 2 sec) was used to evoke a similar number of action potentials and associated increase in [Ca2+]I as those evoked NMDAR activation. In this condition however, CCCP failed to potentiate the action potential‐evoked Δ[Ca2+]i response. Moreover In slices preincubated with Ru360 (10 µM, 30 min), a selective and potent inhibitor of the mitochondrial Ca2+ uptake uniporter, subsequent application of CCCP failed to potentiate the NMDA‐[Ca2+]i response. Taken together, our study support the hypothesis that mitochondria play a critical role in regulating NMDA‐[Ca2+]i dynamics, and therefore, the degree of membrane excitability and firing activity of MNC neurons following NMDAR activation.Grant Funding Source: NIH HL090948‐2
GRK5 overexpression in the RVLM of CHF rats improves autonomic imbalance and restores AT1R and Kv4.3 expressions (686.33)
Authors: Haack Karla , Becker Bryan , Zucker Irving 
Published: June 2021

Chronic heart failure (CHF) is characterized by an overactive Angiotensin II type 1 receptor (AT1R) signaling axis and autonomic imbalance. AT1R is regulated by its phosphorylation by G protein coupled receptor kinase 5 (GRK5). We have shown previously that AT1R and GRK5 are paradoxically increased and that Kv4.3, a potassium channel involved in neuronal excitability, is decreased in the rostral ventrolateral medulla (RVLM) of rats with CHF. We tested the hypothesis is that GRK5 overexpression in the RVLM improves autonomic imbalance and normalizes AT1R and Kv4.3 expression in CHF. CHF was induced by coronary artery ligation and confirmed by echocardiography. Following implantation of radiotelemetry transducers, two weeks of heart rate (HR), mean arterial pressure (MAP) and metabolic cage data were collected before and after either vehicle (Veh) or lentiviral GRK5 (GRK5) injection into the RVLM. HR was decreased in GRK5 rats compared to Veh (293±6 vs 316±2 bpm) while MAP was unchanged. Urine norepinephrine was decreased in GRK5 vs Veh (113±51 vs 252±89 ng/24hrs). Western blot analyses of RVLM micropunches indicated that GRK5 decreased AT1R expression vs Veh (1.2±0.1 vs 1.8±0.4 a.u.) and increased Kv4.3 expression by almost 50% compared to Veh. Taken together, these data suggest that GRK5 overxpression in the RVLM may be protective in CHF by decreasing sympathetic tone and normalizing AT1R and Kv4.3 imbalance.Grant Funding Source: Supported by NHLBI F32HL116172‐01
Excitatory amino acid receptors in the dorsomedial hypothalamus are not involved in the regulation of the tachypneic response induced by chemoreflex (686.34)
Authors: Haibara Andrea , Silva Nathália , Nalivaiko Eugene 
Published: June 2021

EAA receptors into the DMH are involved in the control of sympathoexcitatory component of the chemoreflex, because kynurenic acid into DMH reduces the chemoreflex pressor response. Stimulation of the DMH elicited an increase in respiratory frequency. Considering that activation of inspiratory neurons on the ventral surface of the brainstem can increase the activity of sympathetic preganglionic neurons, we cannot rule out that the blockade of the DMH by kynurenic acid affects the chemoreflex ventilatory responses and consequently the pressor response. This study evaluated the effect of EAA receptors blockade in the DMH on the ventilatory and cardiovascular responses induced by intravenous injection of potassium cyanide (KCN) in conscious rats. Bilateral microinjection of kynurenic acid (2.7 nmol, n=6) into the DMH produced no significant changes on the tachypneic (+198±27 vs +163±19) and bradycardic responses (‐214±7 vs ‐244±17 bpm), but reduced the pressor response (+49±4 vs +23±11 mmHg) of the chemoreflex. Furthermore, the bilateral microinjection of kynurenic acid also produced no changes on baseline cardiovascular parameters (104±3 vs 105±3 mmHg; 330±5 vs 358±12 bpm) and baseline respiratory rate (129±12 vs 120±8 cpm). These results indicate that EAA receptors in the DMH are not involved in the tachypneic response of the chemoreflex, suggesting that the reduction on chemoreflex pressor response induced by kynurenic acid was not a consequence of reduction in respiratory activity.Grant Funding Source: Supported by INCT‐CNPq/ CAPES/ FAPEMIG
Activated pathway from the parabrachial nucleus to rostal ventrolateral medulla during stimulation of cardiac sympathetic afferents (686.8)
Authors: Guo Zhi‐Ling , Longhurst John 
Published: June 2021

Our previous studies have shown that stimulation of cardiac sympathetic afferents activates pontine nuclei like the parabrachial nucleus (PBN) and locus coeruleus (LC) as well as rostral ventrolateral medulla (rVLM), a critical area that controls cardiac sympathoexcitatory responses. However, there is no information on direct influence of pontine nuclei on the rVLM during stimulation of cardiac sympathetic afferents. Thus, the present study evaluated neuronal activation of the pontine nuclei in response to stimulation of cardiac sympathetic afferents, with regard to their projections to the rVLM. Seven to ten days after unilateral microinjection of rodamine‐conjugated microspheres retrograde tracer (100 nl) into the rVLM, rats with bilateral cervical vagotomy were subjected to epicardial application of α, β‐meATP (1.1 to 6.5 mM, in 40 µl) or 0.9% normal saline for six times over 90 min. Repetitive increases in blood pressure were observed in the rats following repeated stimulation of the heart with α, β‐meATP, but not with normal saline. Perikarya containing the microsphere tracer were found in the PBN and, but not in the LC of both groups. Compared to three controls, c‐Fos immunoreactivity and neurons double‐labeled with c‐Fos, an immediate early gene and the tracer were more frequently found in the PBN, but not LC of rats with cardiac stimulation (n=5), particularly in the lateral PBN and Kölliker‐Fuse nucleus. These results suggest that PBN neurons responsive to cardiac sympathetic afferent stimulation frequently project directly to the rVLM, which is known to participate in processing of excitatory cardiovascular responses during stimulation of cardiac sympathetic afferents.Grant Funding Source: NIH grant HL‐66217
Selective regulation of voltage‐gated potassium channel subunits in presympathetic PVN neurons of rats with myocardial infarction (686.9)
Authors: Lee Seul Ki , Ryu Pan Dong , Lee So Yeong 
Published: June 2021

Hypothalamic paraventricular nucleus (PVN) neurons contain presympathetic neurons that project to the rostral ventrolateral medulla (RVLM; PVN‐RVLM neurons) and control cardiovascular sympathetic tones. In this neuronal population, cardiovascular disorders such as hypertension modulate voltage‐gated potassium (Kv) channels, but under myocardial infarction (MI), modulation of Kv channels has not been extensively studied. In the present study, we investigated differences in mRNA expressions of the Kv channel subunits in PVN‐RVLM neurons between sham and MI rats, using single‐cell real‐time RT‐PCR. The results showed that the mRNA level of Kv4.2 was significantly up‐regulated after MI, and this regulation was exclusively found in the dorsal cap subdivision. There was no change in Kv4.3 mRNA level between sham and MI rats in any of the subdivisions. These results suggest that heterogeneous cell populations exist in each subdivision of PVN‐RVLM neurons and that MI selectively regulates the mRNA levels of Kv4.2 in PVN‐RVLM neurons distributed in the dorsal cap subdivision.Grant Funding Source: Supported by the National Research Foundation of Korea (2010‐0015531)
Enhanced dedifferentiation and injury in mouse podocytes lacking CD38 gene (691.4)
Authors: Boini Krishna , Xia Min , Abais Justine , Li Guangbi , Li Pin‐Lan 
Published: June 2021

The absence of CD38 in lymphocytes has been used as a dedifferentiation or low differentiation marker for diagnosis of leukemia. Our recent studies have reported that CD38 deficiency leads to phenotypic plasticity of arterial smooth muscle cells. In the present study, we hypothesized that CD38 and its signaling pathway may participate in the regulation of podocyte differentiation and proliferation and its gene defect or dysfunction may lead to podocyte injury and glomerular sclerosis. CD38 gene targeted mice and their wild type littermates were used to test this hypothesis. Western blot, confocal and RT‐PCR analysis demonstrated that synaptopodin (a marker of differentiation) expression was significantly lower in CD38‐/‐ mice compared to CD38+/+ littermates. In contrast, the proliferation marker cyclin E was significantly higher in CD38‐/‐ mice compared to CD38+/+ littermates. Functional studies showed that the urinary albumin and protein excretion were significantly higher in CD38‐/‐ mice than in CD38+/+ mice. Fluorescent Immunohistochemical analyses also illustrated podocyte damages in the glomeruli from CD38‐/‐ mice, as shown by decreased expression of podocin and enhanced expression of desmin. Visfatin treatment further decreased the expression of synaptopodin and increased the abundance of cyclin E, which were accompanied by more increased glomerular damage in CD38‐/‐ than in CD38+/+ mice. In vitro studies showed that inhibition of CD38 enhances the synaptopodin expression, but decreases the level of cyclin E in podocytes. In conclusion, our observations reveal that the normal expression of CD38 importantly contributes to the regulation of podocyte proliferation and dedifferentiation and that defect of this gene may be a critical mechanism resulting in podocyte injury and glomerular sclerosis.Grant Funding Source: supported by NIH grants DK54927 and HL‐75316
Renal vascular reactivity to AVP in wild type and CD38‐/‐ mice: modulation by nitric oxide, prostanoids, and superoxide (692.9)
Authors: Moss Nicholas , Kopple Tayler , Arendshorst William 
Published: June 2021

Renal vascular responses to AVP were tested in anesthetized wild‐type (WT) and CD38‐/‐ mice that lack the calcium mobilizing second messenger cyclic ADP ribose. Iv injections of AVP (3‐25ng) produced a dose‐dependent decrease in renal blood flow with a minimum of 25±2% below control in WT and 27±2% in CD38‐/‐ mice at the 25ng dose. Renal vascular resistance (RVR) increased by 75±6% in WT and 78±6% in CD38‐/‐ mice. Inhibition of NO synthase with L‐NAME increased the maximum RVR response to AVP from 71±7 to 308±76% in WT and from 86±7 to 388±81% in CD38‐/‐. Cyclooxygenase inhibition with indomethacin increased the maximum RVR response to 125±15% in WT and 120±14% in CD38‐/‐ mice (P<0.001, <0.05). Superoxide suppression with tempol inhibited the maximum RVR response to AVP by 38% in both strains (p<0.005). All vascular responses to AVP were abolished by an AVP V1a receptor antagonist. Thus, vasoconstriction by AVP in the mouse is caused by V1a receptor activation with no concomitant vasodilatation by V2 receptors. However, renal vasoconstrictor responses to AVP are strongly buffered by vasodilatory actions of NO and prostanoids and augmented by the vasoconstrictor actions of superoxide. Unlike AVP, other vasoconstrictor agents show attenuated vasoconstrictor activity in CD38‐/‐ mice which points to a distinct activation mechanism for AVP that appears to be independent of CD38 and its downstream calcium signaling pathway.Grant Funding Source: Supported by HL‐02334
Flow mediation of endothelial‐smooth muscle cell interaction through microRNAs (696.4)
Authors: Chen Li‐Jing , Lee Chih‐I , Lin Ting‐Er , Chiu Jeng‐Jiann 
Published: June 2021

In atherosclerotic lesions, synthetic smooth muscle cells (sSMCs) induce aberrant microRNA (miR) profiles in endothelial cells (ECs) under flow stagnation. Increase in shear stress results in favorable miR modulation to mitigate sSMC‐induced inflammation. The objective of this study was to address the role of miRs in sSMC‐induced EC inflammation and its inhibition by shear stress. Co‐culturing ECs with sSMCs under static condition caused initial increases of four anti‐inflammatory miRs (146a/708/451/98) in ECs followed by decreases below the basal levels at 7 days; the increases for miR‐146a/708 peaked at 24 h and those for miR‐451/98 lasted for only 6‐12 h. Shear stress (12 dynes/cm2) to ECs co‐cultured with sSMCs for 24 h augments the expression of these four miRs. In vivo, these four miRs are not expressed in neointimal ECs in injured arteries under flow stagnation, but become highly expressed under physiological levels of flow. MiR‐146a, ‐708, ‐451, and ‐98 target interleukin (IL)‐1 receptor‐associated kinase, inhibitor of nuclear factor‐κB (NF‐κB) kinase subunit‐γ, IL‐6 receptor, and conserved helix‐loop‐helix ubiquitous kinase, respectively, to inhibit NF‐κB signaling, which exerts negative feedback control on the biogenesis of these miRs. Shear‐induction of these miRs in co‐cultured ECs is regulated by β1 and β3 integrins. NF‐E2‐related factor‐2 is critical for shear‐induction of miR‐146a in co‐cultured ECs. Lentivirus carrying miR‐146a inhibits neointimal formation of mouse carotid arteries induced by blood flow cessation. Our findings indicate that the expressions of miR‐146a/708/451/98 are augmented by atheroprotective shear stress in ECs co‐cultured with sSMCs to inhibit neointimal lesion formation of injured arteries.Grant Funding Source: Supported by NSC‐100‐2325‐B‐400‐011 and NSC‐100‐2321‐B‐400‐001 (to J.‐J.‐C.)
Candida glabrata prevents flow‐dependent cardiac effects through lectinic interaction with coronary endothelial luminal membrane receptors (696.8)
Authors: Torres‐Tirado David , Knabb Maureen , Ramírez‐Zavaleta Candy , De Las Peñas Alejandro , Castaño Irene , Rubio Rafael 
Published: June 2021

Candida glabrata (CG) is an opportunistic fungal pathogen that initiates infection by binding to host cells via specific lectin‐like adhesin proteins. We have previously shown the importance of lectin‐oligosaccharide binding in cardiac responses to flow. Due to the lectinic nature of CG binding, we tested the ability of CG to alter the flow‐induced changes in cardiac function in isolated perfused guinea pig hearts. Binding of CG to isolated coronary endothelial luminal membrane (CELM) receptors was determined by Western blot. CG shifted the coronary flow versus AV‐delay relationship upward, indicating that greater flow was required to achieve the same AV delay. This effect was completely reversed with mannose, partially reversed with galactose and N‐ acetylgalactosamine, but hyaluronan had no effect. In addition, mannose reversed the inhibitory effects of CB on AV delay, coronary perfusion pressure and left ventricular pressure. Western blot results indicate that flow sensitive CELM receptors, ET‐2, Ang I, VCAM‐1, and α‐ adrenergic, bind to CG. We propose that CG directly binds to flow sensitive CELM receptors via lectinic interactions with mannose and disrupts the lectin‐oligosaccharide binding necessary for flow‐induced cardiac responses.Grant Funding Source: Supported by grant of CONACYT CB‐2008/101850
Assessing the effect of shear stress on Aquaporin 1 expression in vascular endothelial cells in vitro (696.9)
Authors: McGrail Kyle , Krane Carissa 
Published: June 2021

The human saphenous vein (HSV) is commonly used in coronary artery bypass grafts. The patency of the vein graft in an arterial environment is limited, thereby requiring a high percentage of autograft recipients to repeat the bypass surgery within 5 years. The main problem that ensues with HSV grafts is due to the development of intimal hyperplasia (IH) which compromises vessel function. The mechanistic reasons for the development of IH and limited HSV patency are not currently understood. However, it has been proposed that the change from venous to arterial shear stress may be a trigger. Aquaporin 1 (AQP1), a water channel protein, is expressed in the plasma membrane of vascular endothelial cells. It is hypothesized that enhanced AQP1 expression may be an early biomarker for the development of IH. The goal of this study was to assess the effect of shear stress on AQP1 expression in cultured endothelial cells. Primary vascular endothelial cells seeded on a gelatin‐coated Ibidi flow chamber grown in static conditions expressed low levels of AQP1 protein that localized around the nucleus. In contrast, AQP1 was present in vesicles throughout the cytoplasm in increasing abundance in cells subjected to low shear stress (6 dynes/cm²) vs. high shear stress (16 dynes/cm²)(p<0.01). These data show that shear stress alters AQP1 abundance and subcellular distribution in vascular endothelial cells in vitro, thus supporting a role for AQP1 as an environmental sensor in HSV grafts.Grant Funding Source: Supported by the University of Dayton Research Council
Pulmonary disease in ZDSD, a rat model of metabolic syndrome (697.1)
Authors: Eaton David , Hu Miriam , Allen Matthew , Peterson Richard , Packer C Subah 
Published: June 2021

Pulmonary hypertension (HBP) and lung fibrosis have been reported in metabolic syndrome (MetS) patients. In a pilot study, ZDSD (PCO), a leptin intact genetic rat model with MetS biomarkers, developed right heart hypertrophy indicative of pulmonary HBP. Accordingly, objectives were to determine: 1. whether pulmonary arterial structural changes have occurred subsequent to dyslipidemia and systemic HBP, 2. if lung fibrosis and 3. left and/or right ventricular hypertrophy has occurred in maturing ZDSD. Wet and dry heart weights and RV/LV+S ratios were measured. Morphometric analyses (Bioquant) of lung section micrographs was performed. Mean data for 24 week‐old male ZDSD, niacin‐treated ZDSD, control lean SD and obese CD were compared with Student’s t‐test for any two means and ANOVA with appropriate post‐test for multiple means; differences considered significant when p<0.05. No lung fibrosis was found. ZDSD arterial walls appear thickened. Interestingly, while ZDSD had greatest whole heart and left ventricular mass, control CD had greatest RV/LV+S ratio suggesting pulmonary hypertension is a consequence of obesity but is independent of metabolic syndrome.Grant Funding Source: Supported by PreClinOmics. D Eaton is a NSF LSAMP) Scholar. M Hu was an Indy Project SEED Scholar.
Real‐time nitric oxide measurements in rat isolated hearts by 4,5‐diaminofluorescein fluorescence (698.11)
Authors: Riess Matthias , Bienengraeber Martin , Cheng Qunli , Keszler Agnes , Weihrauch Dorothee 
Published: June 2021

Real‐time measurement of nitric oxide (NO) before, during and after study interventions has numerous advantages over multiple endpoint measurements at various times. However, no reliable method has been described in Langendorff‐prepared hearts. Rat isolated hearts were loaded for 30 min with 20 µM of the fluorescent dye 4,5‐diaminofluorescein (DAF‐2) whose fluorescence (F) increases irreversibly in the presence of NO. Changes in NO were provoked by any combination of 30/120 min ischemia/reperfusion, the NO donor sodium nitroprusside and/or its scavenger cPTIO. Using a bifurcated fiberoptic probe left ventricular epicardial DAF‐2 F was measured online at 490/540 nm excitation/emission. Multiple regression analysis (alpha .05) was used to compare epicardial F after 185 min perfusion to confocal microscopy (488/550 nm) of transverse slices and to high‐performance liquid chromatography of tissue homogenate. Overall, all three measurements correlated significantly to each other and changed adequately with above treatments. Although online fluorescence lacks the spatial resolution of confocal microscopy it may provide a unique insight into real‐time effects of IR and potential cardioprotective treatments on the production of NO. This may serve as an important adjunct tool to investigate its role in studying cardioprotective strategies in isolated hearts. Supported by Department of Veterans Affairs (CARA‐026‐10F) and NIH.Grant Funding Source: Supported by Department of Veterans Affairs and NIH.
Safety and efficacy of sodium nitrite supplementation for improving vascular endothelial dysfunction in middle‐aged and older healthy adults (698.4)
Authors: DeVan Allison , Brooks Forrest , Evans Trent , Bassett Candace , Santos‐Parker Jessica , Sindler Amy , Chonchol Michel , Bryan Nathan , Giordano Tony , Seals Douglas 
Published: June 2021

Vascular endothelial dysfunction develops with aging as a result of insufficient nitric oxide (NO) bioavailability. Supplementation with nitrite, a precursor to NO, may improve NO bioavailability. We tested the safety, dose (80 vs. 160 mg/d), duration (4 and 10 weeks), and efficacy of oral sodium nitrite for improving endothelial dysfunction in middle‐aged and older (MA/O) adults (n=28, 61±1 yr) in a randomized, placebo‐controlled, double‐blind pilot intervention study. Both doses of nitrite acutely increased plasma nitrite (10 to 20‐fold, p<0.05) and were well‐tolerated without symptomatic hypotension or clinically‐relevant elevations in blood methemoglobin (maximal value=1.2%). Ten weeks of nitrite capsules chronically increased plasma nitrite (p<0.05, both doses) without altering blood pressure. Endothelial function, measured by brachial artery flow‐mediated dilation (FMD), was increased 55‐65% vs. baseline (p<0.05) after 10, but not 4 weeks of nitrite vs. placebo. The reduction in FMD with 20 min of forearm cuff occlusion (ischemia‐reperfusion [I/R] stress) was only half as great (‐50%, p<0.05) after nitrite treatment vs. placebo (‐100%). These results indicate that sodium nitrite supplementation for 10 weeks at 80 or 160 mg/d is well‐tolerated, improves vascular endothelial function, and provides protection from endothelial I/R injury in MA/O adults.Grant Funding Source: Supported by NIH HL107105, RR025780, AG000279
Citrulline ingestion did not improve the age‐associated reduction in nitric oxide synthesis (698.6)
Authors: Kim Il‐Young , Schutzler Scott , Deutz Nicolaas , Wolfe Robert 
Published: June 2021

A reduction in nitric oxide (NO) bioavailability that impairs peripheral blood flow regulation is a natural consequence of aging. Therefore, we investigated the effect of ingestion of citrulline, the precursor of arginine, on de novo arginine and NO synthesis at baseline and during citrulline ingestion. A total of 3g of citrulline was ingested every 15 min for 3 h. A 6‐h stable isotope infusion protocol was performed in young (n=8, 27 ± 1.1 y) and elderly subjects (n=8, 76.6 ± 3.1 y) using primed constant infusions of ring‐ L‐[guanidine‐15N2]arginine, L‐[ureido‐13C,5,5‐2H2]citrulline,and ring‐[2H5]phenylalanine. Basal NO synthesis [0.32 ± 0.03 vs. 0.47 ± 0.05 μmol/kg ffm/h; p < 0.02], but not de novo arginine [12.5 ± 1.60 vs. 16.4 ± 1.47 μmol/kg ffm/h], was significantly lower in the elderly vs. the young. Citrulline ingestion increased de novo arginine synthesis in both the elderly and the young, but to a greater extent in the young [55.4 ± 9.64 vs. 72.3 ± 5.96 μmol/kg ffm/h; p < 0.01]. Citrulline ingestion increased NO synthesis in the young [3.47 ± 0.65 μmol/kg ffm/h; p < 0.01], but not in the elderly [1.26 ± 0.42 μmol/kg ffm/h; p = 0.08]. We conclude that aging reduces NO synthesis. This decrease in NO synthesis cannot be attributed to limited availability of citrulline but to the inability to synthesize NO via NOS.Grant Funding Source: NIH/NIA P30 AG028718