bluuebunny/crossref_metadata_2025_split huggingface dataset:
Blockade of leptin receptor (LepR) in the Carotid Body area attenuated obesity-induced Hypertension
Authors: Shin Mi Kyung , Kim Lenise , Tang Wan-Yee , Polotsky Vsevolod 
Published: May 2023

RATIONALE: Obesity leads to high cardiovascular morbidity and mortality via multiple mechanisms including obstructive sleep apnea (OSA) and hypertension. Obesity leads to high levels of leptin which is produced in adipocytes. Increased leptin levels have also been implicated in increased sympathetic activity and the pathogenesis of hypertension in obesity. However, mechanisms for the effects of leptin on blood pressure are unclear. The carotid bodies (CB) express leptin receptor (LepR), but the mechanisms and consequences of leptin action in CB are unknown. We have previously discovered that high level of leptin enhances hypertension acting on Transient receptor potential melastatin 7 (Trpm7) channel in the CB (Shin et al., 2019). Here, we investigate the relevance of Leptin receptor (LepR) in CB for the pathogenesis of hypertension by obesity. We hypothesize that obesity causes hypertension action on LepR in CB. METHODS: C57BL/6J lean male mice (n = 16) and diet-induced obese male mice (DIO, n = 11) were implanted with telemetry in the left femoral artery for continuous blood pressure monitoring. In DIO mice, the adenoviral vectors carrying anti-sense RNA, Ad-LepR shRNA (n = 6) or Ad-scrambled control shRNA (n = 5) , were applied locally to the CB region. Blood pressure measurements were performed at baseline and, in DIO mice, 9-11 days after CB infection with the adenoviral vector. RESULT: DIO increased mean arterial pressure by 14 mm Hg during the day ( p<0.0 001) and by 9 mm Hg at night ( p <0.001) compared to the lean mice. Ad-LepR shRNA abolished obesity-induced hypertension ( p<0.05). LepR knockdown was particularly effective during the day, when animals were predominantly asleep, decreasing mean arterial pressure by 8.5 mmHg. Control shRNA had no effect on DIO-induced hypertension. CONCLUSION: Our study has shown that inhibition of LepR in the carotid bodies abolished obesity-induced hypertension. 19CDA34700025, HL 133100, HL128970 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Relationship between serum ß-hydroxybutyrate and hepatic fatty acid oxidation in individuals with obesity and NAFLD
Authors: Shryack Grace , Moore Mary , Meers Grace , Wieschhaus Nicole , Alessi Isabella , Johnson Sarah , Wheeler Andrew , Ibdah Jamal , Parks Elizabeth , Rector Scott 
Published: May 2023

Nonalcoholic fatty liver disease (NAFLD), the most common liver disease worldwide, is characterized by the presence of excess lipid (>5%) accumulation which can progress to lobular inflammation (NASH), ballooning, and fibrosis. Lipid breakdown, or mitochondrial fatty acid oxidation (FAO), typically leads to two disparate pathways, ketogenesis or the tricarboxylic acid cycle. In a healthy state, FAO and ketogenesis occur proportionally. Additionally, serum ketones levels, specifically ß-hydroxybutyrate (ß-HB), are often utilized as a surrogate marker for hepatic FAO; yet, whether this relationship exists under conditions of NAFLD is not clearly established. Here, we compared fasting serum ketone levels with direct measurement of mitochondrial palmitate (long chain fatty acid) oxidation from liver biopsies obtained from patients undergoing bariatric surgery stratified based on liver disease severity (n=100). NAFLD progression to NASH was associated with reductions in liver HMGCS2 content and gene expression (P < 0.05) (the rate limiting enzyme in ketosis), while this was not accompanied by differences in serum β-HB (P > 0.05). Worsening liver mitochondrial complete palmitate oxidation corresponded with lower liver Hmgcs2 gene expression (r = 0.30, P = 0.01) but not incomplete or total (complete + incomplete) palmitate oxidation (P > 0.05). Likewise, serum β-HB did not correspond with incomplete, complete, or total palmitate oxidation (P > 0.05). Interestingly, we found that liver Hmgcs2 gene expression and serum β-HB significantly correlated with liver mitochondrial β-HAD activity (r = 0.35, P = 0.007) (r = 0.26, P = 0.04) and the mitochondrial fatty acid transporter CPT1a mRNA (r = 0.50, P < 0.0001) (r = 0.42, P < 0.0001) These results suggest that regulators of ketogenesis may meditate markers in mitochondrial FAO, but serum ß-HB may not a suitable measure of FAO in the context of NAFLD. This work was supported by an NIH R01 DK113701-01 (R.S.R., E.J.P., J.A.I) and was partially supported by VA-Merit Grant I01BX003271-01 (R.S.R.). This work was supported with resources and the use of facilities at the University of Missouri and Harry S. Truman Memorial Veterans Hospital in Columbia, Missouri. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Neuronal Membrane Repair Defect as a Contributor to Amyloid Beta Pathogenesis in Alzheimer's Disease
Authors: Bulgart Hannah , Lopez Perez Miguel , Tucker Alexis , Usmani Maham , Weisleder Noah 
Published: May 2023

Alzheimer’s Disease (AD) is a common neurodegenerative disease that displays two hallmark protein accumulations in the brain – extracellular amyloid beta (Aβ) and intracellular hyperphosphorylated tau. Aβ has been shown to directly penetrate the neuronal cell membrane and damage the membrane. This compromises membrane integrity, increases membrane permeability that alters membrane conductance and elevates intracellular calcium concentrations which contribute to reactive oxygen species production and mitochondrial dysfunction. This damage to the plasma membrane requires a quick and efficient repair mechanism to restore the barrier function of the membrane and avoid neuronal cell death. However, a defect in membrane repair has not been examined as a contributor to AD. Here, we aimed to assess membrane repair capacity in AD in vitro models as a potential contributor to neuronal death. To assess the effect of Aβ on membrane repair kinetics, we exposed primary mouse hippocampal neurons to 1μM recombinant human Aβ42 (rhAβ42) for 16 hours prior to experimentation. Additionally, we treated wildtype neuronal cells with healthy and AD patient with elevated levels of Aβ (PSEN1 M146L mutation) cortical neuron iPSC conditioned media. We also exposed primary mouse hippocampal neurons to cerebrospinal fluid (CSF) from non-AD and AD patients. Treated cells were challenged with an established laser damage assay where a two-photon laser is used to damage the cell membrane in the presence of FM4-64 dye. Dye fluorescence at the injury site is used as a proxy for membrane repair kinetics. Lastly, we investigated autoantibody production targeting proteins involved in membrane repair in non-AD and AD sera and CSF via custom ELISAs. Overall, we observed an induced membrane repair defect when wildtype neuronal cells are treated with rhAβ42, AD iPSC conditioned media, and AD CSF. We also observed a significant increase in autoantibody production in AD biofluids as compared to the non-AD controls. Autoantibody levels were inversely correlated with efficient membrane repair capacity and positively correlated with Aβ concentrations. These results illustrate Aβ’s role in impairing neuronal membrane repair capacity, and the potential contribution of autoantibodies targeting membrane repair proteins in AD. This work is supported by The Ohio State University Dean's Discovery grant and Dept. of Physiology & Cell Biology Nishikawara Student Research grant. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Chronic intermittent hypoxia induced increases in central angiotensin II release in the MnPO
Authors: Farmer George , Bachelor Martha , Little Joel , Cunningham J. 
Published: May 2023

The brain is sensitive to Angiotensin II (ANG II) and we have previously shown that ANG II is released by brain slices containing the median preoptic nucleus (MnPO) and subfornical organ (SFO) in an activity dependent manner. In addition, angiotensin II type 1 receptors and angiotensin converting enzyme 1 are upregulated in the MnPO following chronic intermittent hypoxia (CIH), an animal model of obstructive sleep apnea. Here, we investigate changes in ANG II release in the SFO to MnPO pathway following 7-day CIH treatment.Using isoflurane (2-3%) anesthesia, male Sprague-Dawley rats (250-350g) received microinfusions (0.4 μL) of AAV2-hSyn-ChR2(E123A)-eYFP-WPRE in the SFO. After recovery, rats were subjected to 7 days of CIH (0800-1600 hrs) or Normoxia. The CIH protocol consisted of 6 min cycles (3 min 21% O2, 3 min 10% O2) repeated 10x/hr for 8 hours (during the normal inactive/sleep phase) on 7 consecutive days. For sniffer cell measurements, rats were anesthetized with isoflurane (2-3%) and sagittal slices (300 μm) containing the MnPO and SFO were cut using standard in vitro slice procedures. Sniffer cells consisted of Chinese Hamster Ovary cells transfected with a commercially available plasmid for the angiotensin type 1a (AT1a) receptor (Origene Tech.) and R-GECO (Addgene #32462) as previously described. Sniffer cells were placed on the median preoptic nucleus (MnPO) of sagittal in vitro brain slices. Both spontaneous and evoked (SFO stimulation) changes in fluorescent intensity of sniffer cells on the MnPO were measured.Sniffer cell recordings were made from 5 normoxia and 8 CIH treated rats. The frequency of spontaneous sniffer cell activity in slices from normoxic rats (n = 92) was comparable to rates previously reported in Sprague-Dawley rats. Spontaneous sniffer cell activity in slices from CIH treated rats (n = 156) was increased compared to normoxic treated rats (p < 0.05). Furthermore, bath application of TTX (1 uM) reduced, but did not abolish, spontaneous sniffer cell activity in slices from both normoxic (n = 95, p < 0.001) and CIH (n = 108, p < 0.001) treated rats. Incidence of optogenetic evoked responses in sniffer cells were limited in slices from both the normoxic and CIH treated rats and there were no differences detected in these evoked responses.The current study indicates that spontaneous ANG II release in the MnPO 1) is not entirely action potential dependent, 2) is enhanced following 7-days CIH treatment, and 3) the CIH induced increase is action potential dependent. While optogenetic stimulation of SFO increased sniffer cell activity, CIH had no effect evoked release of ANG II in these preliminary studies. Work supported by: P01 HL088052, R01 HL155977 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Human serum fibrinogen induces brain microvascular endothelial dysfunction and blood-brain barrier dysregulation via dynamin related protein 1 dependent pathway
Authors: Chandra Partha , Rutkai Ibolya , Castorena-Gonzalez Jorge , Busija David 
Published: May 2023

Background: Fibrinogen (Fgn) is one of several pathogenic factors in the brain microvasculature. It is upregulated in the blood of the aged, Alzheimer’s disease, and other neurological disease patients. We explored the possible role of a human serum Fgn (hFgn) mediated mechanism for endothelial and blood-brain barrier (BBB) dysregulation in primary human brain microvascular endothelial cells (HBMEC). Methods: To assess the endothelial and BBB dysregulation ex vivo, we measured protein expression change by western blot and immunofluorescence in hFgn-treated HBMEC. Cell viability was determined by NAD(P)H-dependent 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)-based assay, and in vitro BBB-permeability was assessed by transwell migration assay. Stable DRP1 knockdown cells were developed by transduction of shRNA(h) lentivirus particles in HBMEC. Results: Clinical studies have reported that Fgn is an abundant protein in human blood plasma at concentrations ranging from 1.5–4 mg/mL with a normal half-life of 3–5 days, and the plasma concentration of Fgn increased progressively with age in healthy subjects. We observed that 4 mg/mL of hFgn induced significant cytotoxicity and generated mitochondrial reactive oxygen species in HBMEC within 24 h. With the same concentration of Fgn, we observed that most of the mitochondria were elongated or hyperfused, possibly due to significant reduction of phosphorylated dynamin related protein 1 (pDRP1[S616]) in hFgn-treated HBMEC. Moreover, mitochondrial oxidative phosphorylation (OXPHOS)-related mitochondrial complex-II, -III, and -V proteins were also decreased in hFgn-treated HBMEC. Interestingly, autophagy-related, microtubule-associated protein light chain 3B-II (LC3B-II) and lysosomal membrane-associated protein 2 (LAMP2) decreased, while a negative regulator of autophagy, p62, increased in hFgn-treated HBMEC, suggesting hFgn-mediated induction of defective autophagy. Importantly, hFgn induced BBB permeability, possibly due to loss of several BBB-related proteins such as JAM-A, occludin, ZO-1/-2, and PECAM-1 in HBMEC. DRP1 knockdown by shRNA(h) resulted in reduction of OXPHOS and BBB-related proteins as well as defective autophagy induction in HBMEC. Conclusions: Our results suggest that detrimental effects of elevated Fgn downregulates DRP1, leading to endothelial and BBB dysfunction in the brain microvasculature, which affects neuronal health/function and adds vulnerability to strokes and neurological diseases. HL148836, AG063345, NS114286, AG047296, and AG074489. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Angiotensin II-mediated neuroinflammation in the hippocampus contributes to neuronal deficits and cognitive impairment in heart failure rats
Authors: Campos-Lira Elba , Althammer Ferdinand , Roy Ranjan , Kirchner Matthew , Whitley Kathryn , Davis Steve , Montanez Juliana , Ferreira-Neto Hildebrando , Zafar Usama , Parent Marise , Stern Javier 
Published: May 2023

Background: Chronic hypertension can lead to the development of heart failure (HF), a debilitating disease affecting ~65 million people worldwide. In addition to impaired cardiovascular performance and associated systemic complications, most patients with HF suffer from depression and/or cognitive decline. Although neuroinflammation and brain hypoperfusion occur in humans and rodents with heart failure (HF), the underlying neuronal substrates, mechanisms, and their relative contribution to cognitive deficits in HF remains unknown. Methods: To address this critical gap in our knowledge, we used a well-established HF rat model that mimics clinical outcomes observed in humans, along with a multidisciplinary approach combining behavioral, electrophysiological, neuroanatomical, molecular and systemic physiological approaches. Results: Our studies support neuroinflammation, hypoperfusion/hypoxia and neuronal deficits in the hippocampus of HF rats, which correlated with the progression and severity of the disease. An increased expression of angiotensin II AT1a receptors (AngII-AT1aRs) in hippocampal microglia preceded the onset of neuroinflammation. Importantly, blockade of AT1Rs with a clinically used therapeutic drug (losartan) efficiently reversed neuroinflammatory endpoints (but not hypoperfusion/hypoxia ones), resulting in turn in improved cognitive performance in HF rats. Finally, we show than circulating AngII leaks and access the hippocampal parenchyma in HF rats, constituting a likely source initiating the neuroinflammatory cascade. Conclusions: We provide compelling evidence for a novel mechanism that contributes to cognitive deficits in HF. We identified a neuronal substrate (hippocampus), a novel mechanism (Angiotensin II-driven neuroinflammation) and a potential novel neuroprotective therapeutic target (AngII-AT1aRs) for the treatment of cognitive deficits in HF. DFG Postdoc Fellowship AL 2466/1-1 to FA; National Heart, Lung, and Blood Institute Grant NIH HL090948 to JES, National Institute of Neurological Disorders and Stroke Grant NIH NS094640 to JES and funding provided by the Center for Neuroinflammation and Cardiometabolic Diseases (CNCD) at Georgia State University. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Beta intrusion during N2 sleep is negatively associated with nocturnal heart rate variability in healthy adults
Authors: Migliaccio Gianna , Greenlund Ian , Barkstrom Elyse , Bigalke Jeremy , Nicevski Jennifer , Tikkanen Anne , Carter Jason 
Published: May 2023

Increased cognitive hyperarousal is a proposed mechanism associated with clinical poor sleep including insomnia. An objective marker of nocturnal hyperarousal is high frequency electroencephalography during sleep, including increased beta frequency during stage two (N2) sleep. Acute and chronic poor sleep quality are associated with autonomic dysfunction, but little is known regarding the relationship between nocturnal beta frequency intrusion and nocturnal autonomic function. The purpose of this study was to explore the association between beta spectral power during stage two (N2) sleep and nocturnal heart rate variability (HRV) in healthy female and male adults. We hypothesized that heightened beta spectral power during N2 sleep would be associated with reduced nocturnal HRV. Twenty-four participants (12 males, 12 females; age, 25 ± 1 years; BMI 27 ± 1 kg/m2) underwent an 8-hour overnight sleep opportunity with continuous polysomnography and 5-lead electrocardiogram monitoring. Periods of 5 – 10 minutes of stable N2 sleep absent of cortical arousals, respiratory events, and limb movement-associated arousals were identified (one per cycle) for analysis. Periods from the first two cycles of N2 sleep from the full night were selected for analysis. Beta spectral power from the central and frontal regions and nocturnal HRV data were analyzed and averaged across each hemisphere. Time-domain HRV was quantified as the root mean squared of successive differences (RMSSD) and proportion of R-R intervals (RRI) varying by greater than 50 ms (pNN50). An inverse correlation was observed between central beta power and RRI (R= -0.473, p=0.019), pNN50 (R= -0.450, p=0.028), and RMSSD (R= -0.406, p=0.049). This was paralleled by a similar relationship between frontal beta and RRI (R= -0.487, p=0.016) and pNN50 (R= -0.423, p=0.039). Our results indicate a negative association between N2 beta power and nocturnal HRV measures. These findings suggest that nocturnal hyperarousal may be associated with poor cardiac autonomic function and has implications for individuals with insomnia in whom cognitive hyperarousal is frequently reported. Support is provided by the National Institutes of Health (AA-024892, U54GM115371; P20GM103474, 2TL1 TR002318). This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Regulation of Renin-Angiotensin System Activity and Blood Pressure by Vascular Smooth Muscle Cullin-3
Authors: Golosova Daria , Brozoski Daniel , Lu Ko-Ting , Muskus Veitia Patricia , Kumar Gaurav , Sigmund Curt 
Published: May 2023

Mutations in the ubiquitin ligase scaffold protein Cullin 3 (CUL3) in smooth muscle cells (SMCs) cause vascular dysfunction, arterial stiffness, and severe hypertension. We hypothesized that conditional deletion of CUL3 in SMCs causes severe hypertension through a renin-angiotensin system (RAS)-dependent mechanism. Mice carrying a conditional allele of CUL3 were bred to mice expressing a tamoxifen-inducible CRE-recombinase driven by a smooth muscle promoter (ISM-CRE, control). Tamoxifen was administered to generate smooth muscle CUL3 knockout (S-CUL3KO). Primary aortic SMCs were used to elucidate the contribution of CUL3 to intracellular angiotensin II-mediated calcium flux. Calcium response in SMCs was analyzed via ratiometric confocal fluorescent microscopyS-CUL3KO mice demonstrated hypertension following three weeks of tamoxifen, mean arterial pressure (MAP) was 108±1 vs. 140±1 mmHg (ISM-CRE vs. S-CUL3KO). Aorta from S-CUL3KO mice exhibited impaired vasorelaxation to acetylcholine (ACh, max relaxation: 84±4% vs. 16±9%, p<0.05) and sodium nitroprusside (SNP, max relaxation: 95±3% vs. 56±9%, p<0.05). Captopril administration (7 days) markedly reduced MAP to 84±0.3 mmHg and improved vasorelaxation in response to both ACh (72±6%) and SNP (91±4%) in S-CUL3KO mice, suggesting RAS-dependency of the hypertension. Additionally, candesartan treatment (7 days) substantially decreased MAP from 138±1 to 96±3 mmHg suggesting that hypertension in S-CUL3KO group is angiotensin type-1 receptor mediated. Q-PCR and RNAScope analyses demonstrated no difference in renin expression in the kidney between the S-CUL3KO and control mice suggesting a blunting of the baroreceptor mechanism regulating renin mRNA expression. Equilibrium angiotensin II plasma levels in both groups were not different (2517±352 and 2379±549 pmol/L, p>0.05). Preliminary data demonstrated that acute application of 10 μM of angiotensin II to S-CUL3KO SMCs resulted in a sustained increase in intracellular calcium which was abolished by a preincubation with 2 μM of candesartan.Our data suggest that CUL3 may play a vital role in baroreceptor mechanism in the kidney and regulate angiotensin II response in SMCs which are essential for responding to changes in perfusion pressure. Ultimately, understanding CUL3 target proteins may benefit the development of novel treatments for hypertension. R35 HL144807 (to CDS). This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.