scholarly journals Sex differences in neuronal nitric oxide synthase (nNOS) expression in the paraventricular nucleus (PVN) and subfornical organ (SFO) in angiotensin II (ANG II)‐induced hypertension

2009 ◽  
Vol 23 (S1) ◽  
Author(s):  
Minati Singh ◽  
Baojian Xue ◽  
Meredith Hay ◽  
Alan Kim Johnson
Keyword(s):  
Nitric Oxide ◽  
Sex Differences ◽  
Angiotensin Ii ◽  
Nitric Oxide Synthase ◽  
Paraventricular Nucleus ◽  
Neuronal Nitric Oxide Synthase ◽  
Ang Ii ◽  
Induced Hypertension ◽  
Oxide Synthase ◽  
Nnos Expression

Abstract 15532: Altered Ubiquitination and Stability of Protein Inhibitor of Neuronal Nitric Oxide Synthase in the Paraventricular Nucleus of Chronic Heart Failure Rats: Role of Angiotensin II

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Neeru Sharma ◽  
Xuefei Liu ◽  
Hong Zheng ◽  
Kaushik Patel
Keyword(s):  
Nitric Oxide ◽  
Heart Failure ◽  
Angiotensin Ii ◽  
Chronic Heart Failure ◽  
Paraventricular Nucleus ◽  
Neuronal Nitric Oxide Synthase ◽  
Ang Ii ◽  
Protein Inhibitor ◽  
Ubiquitin Proteasome ◽  
Oxide Synthase

Introduction and Hypothesis: Expression of neuronal nitric oxide synthase (nNOS) is decreased in the paraventricular nucleus (PVN) of rats with chronic heart failure (CHF), however the underlying molecular mechanism/s remain unclear. Recently, we demonstrated, Angiotensin II (Ang II) mediated increase in PIN: protein inhibitor of nNOS (0.76±0.10 Sham vs 1.12±0.09* CHF) which is known to down-regulate nNOS through disruption of active dimers (~60% decrease in dimer/monomer ratio) in the PVN of rats with CHF. Functionally impeded monomeric enzyme is degraded by ubiquitin proteasome system. Interestingly, PIN transcript levels remain unchanged in the PVN in CHF (1.00±0.23 Sham vs. 1.1±0.28 CHF). This observation prompted us to elucidate the molecular mechanism for the accumulation of PIN post-transcriptionally in the PVN in CHF Methods and Results: We used coronary artery ligation model of CHF in rats (6-8 weeks past ligation) and neuronal NG108-15 hybrid cell line. PIN translation was inhibited using cyclohexamide (CHX) for 0-4h after 20h of pretreatment with Ang II in NG108 cells. CHX mediated decrease in PIN expression was ameliorated with Ang II (0.19±0.04 vs 0.41±0.06* 4h). Proteasome inhibitor lactacystin (LC) treatment dramatically elevates PIN level suggesting the involvement of proteasome system in PIN regulation. Immunoprecipitation with ubiquitin antibody showed decrease PIN-Ub conjugates in Ang II-treated cells (1.04 ± 0.05 LC vs. 0.62 ± 0.07* LC AngII). In vitro ubiquitination assay in cells transfected with pCMV-(HA-Ub)8 vector revealed reduction of HA-Ub-PIN conjugates after Ang II treatment (9.2 ± 2.2 LC vs. 4.5 ± 0.6* LC Ang II). Furthermore, there was decreased accumulation of PIN-Ub conjugates in the PVN of CHF rats compared to Sham as revealed by immunohistochemistry. Conclusions: Taken together, our studies revealed that PIN is targeted for rapid degradation by the ubiquitin-proteasome pathway and Ang II delays the rate of degradation resulting in accumulation of PIN. We conclude that post-translational accumulation of PIN, mediated by Ang II, leads to a decrease in the dimeric active form of nNOS as well as protein levels of nNOS, which may lead to reduced nitric oxide resulting in over-activation of sympathetic drive during CHF.

scholarly journals Anteroventral third ventricle (AV3V) lesion affects hypothalamic neuronal nitric oxide synthase (nNOS) expression following water deprivation

2011 ◽  
Vol 86 (3-4) ◽  
pp. 239-245 ◽  
Author(s):  
Fábio Alves Aguila ◽  
Gabriela Ravanelli Oliveira-Pelegrin ◽  
Song Tieng Yao ◽  
David Murphy ◽  
Maria José Alves Rocha
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Water Deprivation ◽  
Third Ventricle ◽  
Neuronal Nitric Oxide Synthase ◽  
Oxide Synthase ◽  
Nnos Expression

Abstract 085: CHIP: E3 Ubiquitin Ligase Mediates Proteasomal Degradation of Neuronal Nitric Oxide Synthase in the Paraventricular Nucleus of Rats with Heart Failure

Hypertension ◽  
2017 ◽  
Vol 70 (suppl_1) ◽  
Author(s):  
Neeru M Sharma ◽  
Kenichi Katsurada ◽  
Xuefei Liu ◽  
Kaushik P Patel
Keyword(s):  
Nitric Oxide ◽  
Heart Failure ◽  
Nitric Oxide Synthase ◽  
Paraventricular Nucleus ◽  
Ubiquitin Ligase ◽  
Protein A ◽  
Neuronal Nitric Oxide Synthase ◽  
Proteasomal Degradation ◽  
Oxide Synthase

The exaggerated sympathetic drive is a characteristic of heart failure (HF) due to reduced neuronal nitric oxide synthase (nNOS) within the paraventricular nucleus (PVN). Previously we have shown that there were increased accumulation of nNOS-ubiquitin (nNOS-Ub) conjugates in the PVN of rats with HF (1.0±0.05 Sham vs. 1.29±0.06 HF) due to the increased levels of PIN (a protein inhibitor of nNOS, known to dissociate nNOS dimers into monomers) (0.76±0.10 Sham vs. 1.12±0.09 HF) and decreased levels of tetrahydrobiopterin (BH4): a cofactor required for stabilization of nNOS dimers (0.62±0.02 Sham vs. 0.44±0.03 HF). We also showed that there is blunted nitric oxide-mediated inhibition of sympathetic tone via the PVN in HF. Here we examined whether CHIP(C-terminus of Hsp70 -interacting protein), a chaperone-dependent E3 ubiquitin-protein isopeptide ligase known to ubiquitylate Hsp90-chaperoned proteins could act as an ubiquitin ligase for nNOS in the PVN. Immunofluorescence studies revealed colocalization of nNOS and CHIP in the PVN indicating their possible interaction. CHIP expression was increased by 50% in the PVN of rats with HF(0.96±0.08 Sham vs.1.44±0.10* HF). It is shown that Hsp90 protects nNOS from ubiquitination while Hsp70 promotes the ubiquitination and degradation. We observed significant upregulation of Hsp70 (0.49±0.03 Sham vs. 0.65±0.02* HF) with a trend toward the decrease in Hsp90 expression (0.90±0.07 Sham vs. 0.71±0.06 HF). The opposing effects of the two chaperones could account for the increased CHIP-mediated ubiquitination and degradation of dysfunctional nNOS monomers in the PVN of rats with HF. Furthermore, neuronal NG108-15 cell line transfected with the pCMV3-CHIP-GFP spark (CHIP overexpression plasmid) showed approximately 74% increase in CHIP with concomitant 49% decrease in nNOS expression. In vitro ubiquitination assay in NG108 cells transfected with pCMV-(HA-Ub) 8 and pCMV3-CHIP-GFP spark plasmid reveal increased HA-Ub-nNOS conjugates (1.13 ± 0.09 Scramble vs. 1.65 ± 0.12* CHIP plasmid). Taken together, our results identify CHIP as an E3 ligase for ubiquitination of dysfunctional nNOS and CHIP expression is augmented during HF leading to increased proteasomal degradation of nNOS in the PVN.

scholarly journals Neuronal nitric oxide synthase and calbindin delineate sex differences in the developing hypothalamus and preoptic area

2007 ◽  
Vol 67 (10) ◽  
pp. 1371-1381 ◽  
Author(s):  
Michelle Edelmann ◽  
Cory Wolfe ◽  
Elka M. Scordalakes ◽  
Emilie F. Rissman ◽  
Stuart Tobet
Keyword(s):  
Nitric Oxide ◽  
Sex Differences ◽  
Nitric Oxide Synthase ◽  
Preoptic Area ◽  
Neuronal Nitric Oxide Synthase ◽  
Oxide Synthase

Neuronal nitric oxide synthase modulates rat renal microvascular function

1998 ◽  
Vol 274 (3) ◽  
pp. F516-F524 ◽  
Author(s):  
Atsuhiro Ichihara ◽  
Edward W. Inscho ◽  
John D. Imig ◽  
L. Gabriel Navar
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Neuronal Nitric Oxide Synthase ◽  
Macula Densa ◽  
Ang Ii ◽  
Sprague Dawley ◽  
Vasoconstrictor Response ◽  
Arteriolar Tone ◽  
Oxide Synthase

This study was performed to determine the influence of neuronal nitric oxide synthase (nNOS) on renal arteriolar tone under conditions of normal, interrupted, and increased volume delivery to the macula densa segment and on the microvascular responses to angiotensin II (ANG II). Experiments were performed in vitro on afferent (21.2 ± 0.2 μm) and efferent (18.5 ± 0.2 μm) arterioles of kidneys harvested from male Sprague-Dawley rats, using the blood-perfused juxtamedullary nephron technique. Superfusion with the specific nNOS inhibitor, S-methyl-l-thiocitrulline (l-SMTC), decreased afferent and efferent arteriolar diameters, and these decreases in arteriolar diameters were prevented by interruption of distal volume delivery by papillectomy. When 10 mM acetazolamide was added to the blood perfusate to increase volume delivery to the macula densa segment, afferent arteriolar vasoconstrictor responses tol-SMTC were enhanced, but this effect was again completely prevented after papillectomy. In contrast, the arteriolar diameter responses to the nonselective NOS inhibitor, N ω-nitro-l-arginine (l-NNA) were only attenuated by papillectomy.l-SMTC (10 μM) enhanced the efferent arteriolar vasoconstrictor response to ANG II but did not alter the afferent arteriolar vasoconstrictor responsiveness to ANG II. In contrast, l-NNA (100 μM) enhanced both afferent and efferent arteriolar vasoconstrictor responses to ANG II. These results indicate that the modulating influence of nNOS on afferent arteriolar tone of juxtamedullary nephrons is dependent on distal tubular fluid flow. Furthermore, nNOS exerts a differential modulatory action on the juxtamedullary microvasculature by enhancing efferent, but not afferent, arteriolar responsiveness to ANG II.

scholarly journals Optogenetic Stimulation Reduces Neuronal Nitric Oxide Synthase Expression After Stroke

Neurosurgery ◽  
2019 ◽  
Vol 66 (Supplement_1) ◽  
Author(s):  
Arjun Vivek Pendharkar ◽  
Daniel L Smerin ◽  
Lorenzo Gonzales ◽  
Eric Wang ◽  
Sabrina L Levy ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Motor Cortex ◽  
Functional Recovery ◽  
Neuronal Nitric Oxide Synthase ◽  
Optogenetic Stimulation ◽  
Oxide Synthase ◽  
Nnos Expression ◽  
Stimulation Of ◽  
Nnos Inhibition

Abstract INTRODUCTION Poststroke optogenetic stimulation has been shown to enhance neurovascular coupling and functional recovery. Neuronal nitric oxide synthase (nNOS) has been implicated as a key regulator of neurovascular response in acute stroke but its role in subacute recovery remains unclear. Here we investigate nNOS expression in stroke mice undergoing optogenetic stimulation of the contralesional lateral cerebellar nucleus (cLCN). We also examine the effects of nNOS inhibition on functional recovery using a pharmacological inhibitor targeting nNOS. METHODS Transgenic Thy1-ChR2-YFP male mice (10-12 wk) were used. Stereotaxic surgery was performed to implant a fiber cannula in the cLCN and animals underwent intraluminal middle cerebral artery suture occlusion (30 min). Optogenetic stimulation began at poststroke (PD) day 5 and continued until PD14. Sensorimotor tests were used to assess behavioral recovery at PD4, 7, 10, and 14. At PD15, primary motor cortex from both ipsi- and contralesional motor cortex (iM1, cM1) were dissected. nNOS mRNA and protein levels were examined using quantitative polymerase chain reaction and western blot. In another set of studies, nNOS inhibitor ARL 17477 dihydrochloride (10 mg/kg, intraperitoneally) was administered daily between PD5-14 and functional recovery was evaluated using sensorimotor tests. RESULTS cLCN stimulated stroke mice demonstrated significant improvement in speed (cm/s) on the rotating beam task at PD10 and 14 day (P < .05, P < .001 respectively). nNOS mRNA and protein expression was significantly and selectively decreased in cM1 of cLCN stimulated mice (P < .05). The reduced nNOS expression in cM1 was negatively correlated with improved recovery (R2 = −0.839, Pearson P = .009). nNOS inhibitor-treated stroke mice exhibited a significant functional improvement in speed at PD10, when compared to stroke mice receiving vehicle (saline) (P < .05). CONCLUSION Our results suggest that nNOS may play a maladaptive role in poststroke recovery. Optogenetic stimulation of cLCN and systemic nNOS inhibition produce functional benefits after stroke.

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