bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intracerebroventricular Administration of Fibroblast Growth Factor Receptor Inhibitor Attenuates High‐Phosphate Diet‐Induced Exercise Pressor Reflex Overactivation in Rats
Authors: Kim Han‐Kyul , Mizuno Masaki , Iwamoto Gary A. , Ishizawa Rie , Mitchell Jere H. , Smith Scott A. , Vongpatanasin Wanpen 
Published: June 2021

Inorganic phosphate (Pi) is used extensively as a preservative and a flavor enhancer in the Western diet. As a result, dietary Pi intake in the US far exceeds the recommended daily allowance. A previous study from our laboratory has demonstrated that dietary Pi excess induces an exaggerated rise in blood pressure and renal sympathetic nerve activity (RSNA) in response to muscle contraction. This augmented pressor response was further shown to be mediated by an exaggerated skeletal muscle exercise pressor reflex (EPR). However, the underlying mechanism responsible for the EPR overactivity observed remains unknown. Fibroblast growth factor (FGF) 23 is one of the principle hormones involved in Pi homeostasis. It can cross the blood brain barrier and activate FGF receptors in the brainstem. The purpose of this study was to test the hypothesis that Pi‐induced EPR overactivity is mediated by brain FGF receptor stimulation. Sprague‐Dawley rats were fed a normal Pi (NP) diet containing 0.6% Pi (n=13) or a high Pi (HP) diet containing 1.2% Pi (n=13) for three months. Subsequently, mean arterial pressure (MAP) and RSNA responses to EPR activation were measured in decerebrate NP and HP animals. MAP and RSNA measures were obtained before and after intracerebroventricular (ICV) administration of the FGF receptor inhibitor PD173074. ICV PD173074 administration significantly reduced the exaggerated MAP (Δ=35±4 vs. 9±2 mmHg, P<0.01) and RSNA responses (Δ=84±16 vs. 32±7 %, P<0.01) to electrically induced hindlimb muscle contraction via ventral root stimulation (i.e. EPR activation) in the HP group, but did not significantly affect the responses in the NP group (ΔMAP =18±3 vs. 13±2 mmHg, ΔRSNA=40±10 vs. 30±7 %). MAP and RSNA responses to intra‐arterial infusion of capsaicin in the hindlimb (designed to assess the metabolically‐sensitive component of the EPR) were also attenuated by PD173074 in HP rats (ΔMAP=43±4 vs. 24±5 mmHg, ΔRSNA=98±25 vs. 48±9 %, P≤ 0.02) but remained unchanged in NP animals (ΔMAP=32±4 vs. 34±4 mmHg, ΔRSNA=61±12 vs. 66±18 %). The findings suggest that stimulation of FGF receptors in the brain contributes significantly to the generation of exaggerated EPR activity after excess Pi consumption. Moreover, the data demonstrate a novel action of central FGF receptor inhibition by reversing the EPR overactivity manifest in animals fed a high Pi diet. Importantly, the results implicate dietary Pi as a potential therapeutic target for the prevention and/or treatment of abnormally large sympathetic and blood pressure responses to exercise.Support or Funding InformationNIH 5RO1HL133179‐02This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Heat treatment attenuates the exaggerated exercise pressor reflex in rats with peripheral artery disease
Authors: Xing Jihong , Lu Jian , Li Jianhua 
Published: June 2021

Femoral artery occlusion in rats has been used to study human peripheral artery disease (PAD). The responses of blood pressure (BP) and sympathetic nerve activity are exaggerated during static exercise in PAD rats with femoral artery occlusion. The purpose of the current study was to examine if heat treatment (a prior heat exposure) has beneficial effects on the exaggerated exercise pressor reflex in PAD rats. Basal muscle temperature (Tm) was 35.6±0.1 °C in control rats (n=3); and 34.2±0.1 °C in PAD rats (n=5; P<0.05 vs. control rats). As Tm was increased by ~1.5 °C and this was maintained for 30 min, core temperature was not altered in control group and PAD group. The heat treatment was performed 2 times daily for 3 days. Then we examined the BP response to static muscle contraction. The greater mean arterial pressure (MAP) response was observed in PAD rats (31±5 mmHg in PAD rats/n=6 vs. 22±3 mmHg in control rats/n=8; P<0.05). Heat treatment attenuated amplification of BP response in PAD rats (MAP response: 24±3 mmHg in PAD rats with heat treatment/n=5; P<0.05 vs. no heat treatment). Note that no significant difference in developed muscle tension during muscle contraction was seen in control rats and PAD rats with heat treatment or without heat treatment (P>0.05). Our data support the hypothesis that a prior heat exposure plays an inhibitory role in modifying exaggeration of the exercise pressor reflex in PAD.Support or Funding InformationNIH P01 HL134609This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Evidence of a Shear Stress Stimulus Profile Dependent Impact of Cycling Training on Flow‐Mediated Dilation
Authors: King Trevor James , Pyke Kyra 
Published: June 2021

Lower limb endurance training can improve conduit artery flow‐mediated dilation (FMD) in response to transient increases in shear stress (reactive hyperemia; RH‐FMD) in both the upper and lower limbs. Sustained increases in shear stress recruit a partially distinct transduction pathway and elicit a physiologically relevant FMD response that appears to provide distinct information regarding endothelial function (sustained shear stress‐FMD, SS‐FMD). However, the impact of training on SS‐FMD is not well understood.PURPOSETo determine the impact of cycling training on handgrip exercise induced brachial artery (BA) FMD (BA SS‐FMD) and calf plantar‐flexion induced superficial femoral artery (SFA) FMD (SFA SS‐FMD).METHODS28 young males were randomized to control (n=12) or training (n=16) groups. Participants in the training group cycled 30 min/day, 3 days/week for 4 weeks at 80 % heart rate reserve. RH‐FMD and SS‐FMD was assessed in the BA and SFA pre and post‐intervention via Duplex ultrasound.RESULTSData are mean ±SD. Training did not impact SS‐FMD in either artery, and RH‐FMD in the SFA was also unchanged (p>0.05). When controlling for the shear rate stimulus via covariate analysis, BA RH‐FMD improved in the training group (p=0.05) (Control: pre‐ 5.7 ± 2.4%, post‐ 5.3 ± 2.4%; training: pre‐ 5.4 ± 2.5%, post‐ 7.2 ± 2.4%).CONCLUSIONSEndurance training resulted in non‐uniform adaptations to endothelial function, with an isolated impact on the brachial artery, and on the ability to transduce a transient increase in shear stress.Support or Funding InformationFunded by NSERCThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Breast Cancer Survivors Improved Forearm Blood Flow Following a Single Bout of Aerobic Exercise: Preliminary Results
Authors: Grigoriadis Georgios , Hibner Brooks A. , Schroeder Elizabeth C. , Rosenberg Alexander J. , Danciu Oana C. , Fernhall Bo , Baynard Tracy 
Published: June 2021

Chemotherapy impairs endothelial and resistance artery function contributing to arterial dysfunction, a cardiovascular disease (CVD) risk factor. In healthy individuals, a bout of aerobic exercise acutely improves arterial function. However, the acute effect of aerobic exercise on resistance artery function has not been examined in breast cancer survivors (BCS).PURPOSETo examine the effect of a single bout of aerobic exercise on forearm blood flow in BCS.METHODSSeven BCS (48 ± 4 yrs; 26.0 ± 2.8 kg/m2), 1–5 year post‐chemotherapy treatments and eight female controls (44 ± 9 yrs; 24.2 ± 5.3 kg/m2) completed 30 minutes of cycling exercise at 65% of their maximal aerobic capacity. Cardiac output (Q), Heart rate (HR), mean arterial pressure (MAP), and forearm blood flow (FBF) were assessed at baseline, 15 and 45 minutes post exercise. Automated ambulatory blood pressure monitor was used to acquire Q, HR, and MAP. FBF and Peak FBF was measured with strain‐gauge plethysmography at rest and following 5 minutes of upper arm occlusion respectively. Reactive hyperemia was calculated as the change between baseline and peak FBF. Area under the curve was calculated by including 13 measurements after the 5 min occlusion. Conductance was estimated as FBF divided by mean arterial blood pressure.RESULTSSee Table. In BCS and control groups baseline FBF and conductance increased 15‐min post‐exercise and returned to baseline at 45 minutes post exercise (p<0.05). MAP decreased at 45‐min post‐exercise in both groups (p<0.05). HR was elevated at 15‐min and 45‐min in both groups (p<0.001), while BCS had an overall higher HR (p<0.05). There were no changes in peak FBF, reactive hyperemia area under the curve, peak conductance and Q following exercise.CONCLUSIONBaseline forearm blood flow increased in breast cancer survivors following a single bout of aerobic exercise likely as a result of acute forearm vasodilation. In addition, breast cancer survivors did not exhibit differences at baseline or following exercise suggesting that arterial function was preserved 1–5 years following chemotherapy.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Age‐dependence of Methylation, Transsulfuration and Glutathione Synthesis Pathways in Human Frontal Cortex
Authors: Deth Richard , Schrier Matthew , Dong Jianan , Lemle Marian , Trivedi Malav 
Published: June 2021

Neuronal synthesis of the antioxidant glutathione (GSH) depends upon availability of cysteine, provided either by cellular uptake or by transsulfuration of homocysteine generated by the methionine cycle of methylation (Fig. 1). To evaluate age‐dependent changes in the relative contribution of these two cysteine sources, we measured redox and methylation metabolite levels in postmortem human frontal cortex from subjects across the lifespan. Levels of the transsulfuration intermediate cystathionine were significantly decreased in 60–80 yr‐old subjects, indicating that the balance between these two cysteine sources shifts to transsulfuration in older age. This shift was accompanied by decreased methionine and S‐adenosylmethionine, and an increase in homocysteine, indicating lower activity of the folate and B12‐dependent enzyme methionine synthase (MS), consistent with earlier finding of decrease MS expression with age. Cystathionine levels in 10 yr‐old autistic subjects were decreased, similar to those of 60 yr‐old subjects. In vitro studies with human neuronal cells showed that the pro‐inflammatory cytokine TNF‐alpha increased transsulfuration and inhibited MS activity in association with decreased cysteine uptake. Transsulfuration pathway enzymes cystathionine beta synthase (CBS) and cystathionine gamma lyase (CGL) both produce hydrogen sulfide, which inhibits oxidative respiration and increases glycolysis. This action decreases production of reactive oxygen species (ROS), limiting the demand for antioxidant. Together these observations illustrate how an age‐dependent increase in transsulfuration links antioxidant synthesis to methylation status in human brain. TNF‐alpha, whose levels increase with age, may be a regulator of transsulfuration, with important implications for epigenetic regulation during early brain development.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Increased Mitochondrial ROS Generation from Complex III Causes Mitochondrial Damage and Increases Endoplasmic Reticulum Stress
Authors: Chen Qun , Allegood Jeremy C. , Thompson Jeremy , Toldo Stefano , Lesnefsky Edward J. 
Published: June 2021

RationaleMitochondrial dysfunction contributes to greater susceptibility to injury from superimposed disease in the aged heart. Aging decreases complex III activity and increases ROS production from complex III. Oxidative stress from mitochondria can trigger endoplasmic reticulum (ER) stress.ObjectiveTo study the contribution to additional mitochondria dysfunction and ER stress from Complex III generated ROS.MethodsAntimycin A (AA) (0.4mg/kg i.p.), a complex III inhibitor that increases ROS, was given to adult C57/bl/6 mice and function (echo), mitochondria function and ER stress assessed after 48 hrs.ResultsLow dose in vivo AA led to only mild cardiac dysfunction and no inhibition of respiration through complex III (succinate respiration). AA decreased complex I activity and respiration (glutamate+malate). ER stress increased shown by greater CHOP (transcription factor C/EBP homologous protein) expression (Figure). Susceptibility to mitochondria permeability transition pore (PTP) opening was increased as shown by decreased calcium retention capacity.ConclusionIncreased ROS from complex III damages complex I and increases ER stress with greater PTP susceptibility, mechanisms of enhanced injury observed in the aged heart with superimposed disease including ischemia and reperfusion.Support or Funding InformationThis work was supported by the Office of Research and Development, Medical Research Service Merit Review Award (2IO1BX001355‐01A2) and Department of Veterans Affairs (EJL); National Institutes of Health NIH R21AG054975‐01 (QC).

Vechile(n=6)
AA(n=5)

Cardiac output/beat (ul)
40±2
29±2*

Oxidative phosphorylation (nAO/min/mg protein) Glutamate+malate
388±14
332±10*

Succinate
531±32
538±20

Complex I (mU/mg protein)
841±61
612±38*

Calcium Retention Capacity (nmol calcium/mg protein)
1033±56
848±52*

Mean ± SEM:
p<0.05 vs. Vechicle.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Mitochondrial ultrastructure, function, and calcium buffering by massive calcium loading observed using advanced cryo‐electron microscopy, high‐resolution respirometry and spectrofluorimetry
Authors: Strubbe Jasiel Omil , Schrad Jason , Parent Kristin N , Conway James , Bazil Jason N 
Published: June 2021

Excessive calcium accumulation is the main cause of cardiac tissue and cell death after a myocardial infarction. As a result of calcium overload, mitochondria become dysfunctional, produce excessive reactive oxygen species (ROS), cannot support the cellular energetic demand, and activate the cyclosporine A‐sensitive mitochondrial permeability transition pore. To discern the molecular, bioenergetic, and structural events associated with this phenomenon, we collected and analyzed a time‐course series of images obtained by utilizing recent advances in electron cryo‐microscopy methods. Energized mitochondria exposed to high calcium boluses, sufficient to elicit mitochondrial permeability transition, resulted in the formation of calcium phosphate granules. Under high calcium loading, the size of the calcium‐phosphate granules ranged from 50–120 nm causing OMM/IMM rupture. CsA treatment resulted in mitochondria with aberrant morphologies, increased cristae density and number, and with larger calcium‐phosphate granules ranging from 40–200 nm. The OMM was partially or completely lost; however, the mitochondria were fully functional and capable of synthesizing ATP. Our tomographic reconstruction placed these granules in close vicinity to the IMM and cristae. In addition, CsA treatment increases the calcium buffering power at greater calcium concentrations, whereas untreated mitochondria had much lower calcium buffering. Our results demonstrate that these granules form an intricate part of the mitochondrial calcium sequestration system. Overall, these results suggest CsA may interact with IMM components to: 1) modulate calcium buffering by facilitating more abundant and larger calcium phosphate granules and 2) preserve the cristae shape and number which avoids cytochrome c loss and mitochondrial permeability transition. Our data reveal that drugs capable of modulating cristae shape and number may be an effective strategy to prevent mitochondrial dysfunction stemming from calcium overload.Support or Funding InformationThis work was supported by NIH grant R00‐HL121160.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Targeting of reactive isolevuglandins in mitochondrial dysfunction and inflammation
Authors: Mayorov Vladimir , Uchakin Peter , Amarnath Venkataraman , Dikalova Anna , Panov Alexander , Zackert Bill , Davis Sean , Dikalov Sergey 
Published: June 2021

Inflammation is implicated in cardiovascular diseases, acute kidney injury, lung and heart failure, which represent major causes of morbidity and mortality in Western Societies. Despite use of multiple drugs, both chronic and acute inflammation is still remaining a major health burden. Inflammation produces highly reactive dicarbonyl lipid peroxidation products, isolevuglandins (isoLG) which reacting with lysine residues of proteins covalently modify and cross‐link proteins. Mitochondrial dysfunction has been associated with inflammation; however, its pathophysiological role and molecular mechanisms are still obscure. We propose that inflammation‐induced mitochondrial isoLG play a key role in mitochondrial dysfunction and mortality. To test this hypothesis, we have (a) investigated the mitochondrial dysfunction in response to synthetic isoLG and isoLG adducts; (b) developed new mitochondria‐targeted isoLG scavenger mito2HOBA by conjugating the lipophilic cation triphenylphosphonium to 2‐hydroxybenzylamine; (c) tested if mito2HOBA protects from mitochondrial dysfunction and mortality using LPS model of inflammation. Acute isoLG exposure of mitochondria or treatment with low‐molecular isoLG adducts with lysine, ethanolamine or phosphatidylethanolamine inhibits mitochondrial respiration and attenuates Complex I activity while complex II function is much more resistant to isoLG. To test the pathophysiological role of mitochondrial isoLG we have studied therapeutic potential of mito2HOBA. We have confirmed that mito2HOBA vividly accumulates in isolated mitochondria and it is highly reactive with isoLG compared with untargeted 2HOBA. In vivo studies of isoLG‐mediated mitochondrial dysfunction in mouse LPS model showed that mito2HOBA supplementation in drinking water (0.1 g/L) increased animals survival by 3‐fold and improved complex I‐mediated respiration. These data unambiguously support the role of mitochondrial isoLG in mitochondrial dysfunction in inflammation. We conclude that mitochondrial isoLG can be a promising therapeutic target in inflammation and conditions associated with mitochondrial oxidative stress and dysfunction.Support or Funding InformationNavicent Health Foundation; NIH/NHLBI 1R01HL124116This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Neprilysin colocalizes with the V‐ATPase in kidney A‐type intercalated cells: possible role in urinary acidification
Authors: Bouley Richard , Muhsin Saif , Hong Wei Yan , Nair Anil , Cheung Pui , Brown Dennis 
Published: June 2021

Intercalated cells (IC) in kidney collecting ducts are essential for acid‐base homeostasis. A proteomic analysis of these cells after purification by FACS revealed unexpectedly that they express high levels of neprilysin, a neutral protease, previously reported to be located in the brush border of proximal tubule cells. Therefore, we re‐examined the distribution of neprilysin in the kidney by immunohistochemistry and western blot analysis. Using anti‐neprilysin antibodies and two collecting duct markers: anti‐AQP2 antibody (principal cells) and anti‐A1 subunit v‐ATPase subunit (intercalated cells), we found that neprilysin was detectable not only in the proximal tubule, but also in ICs (but not principal cells) in all regions of the collecting duct. A similar distribution of neprilysin was seen in both mouse and rat kidneys. We then used an anti‐pendrin antibody to identify B‐type ICs in cortical collecting ducts. Only 35% of IC‐B population express neprilysin. Western blot analysis using an antibody against neprilysin showed that both cortical and medullary membrane preparations expressed neprilysin, and that female mice express more neprilysin than males in the cortex. However, this sex difference is not present in the medullary preparation, and we, therefore, attribute it mainly to a difference in proximal tubule expression. A similar result was observed in the kidneys of knockout mice that lack the IC‐specific B1 subunit of the V‐ATPase. In order to study the potential role of neprilysin in renal physiology, we treated male mice for 3 days with thiorphan, a selective neprilysin inhibitor. We measured a slight reduction of urine osmolality 1851 ± 160 to 1357 ± 240 (p=0.12) and an increase in urine volume 0.86 ± 0.21 to 1.48 ± 0.50, p= 0.23). In contrast, the change in urine pH was significant, increasing from 6.6 ± 0.1 to 6.9 ± 0.1, (n=3, p= 0.029) with the inhibitor, suggesting a role of neprilysin in acid excretion, possibly via IC function and V‐ATPase activity. In summary, we found that neprilysin is highly expressed in A‐ICs, where it colocalizes with the V‐ATPase. Its expression is higher in female mice, and it may have an as yet undetermined role in renal acid excretion.Support or Funding InformationThis work was supported by National Institutes of Health (NIH) grant DK096586 (D. Brown). The Zeiss LMS 800 confocal system in the Program in Membrane Biology (PMB) Microscopy Core was purchased using an NIH Shared Instrumentation Grant S10 RR031563‐01 (DB).This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Differential regulation of vacuolar H+‐ATPase subunits by Transforming Growth Factor beta 1 (TGF‐β1) in salivary ducts
Authors: Roussa Eleni , Kluge Milena , Namkoong Eun , Park Kyungpyo 
Published: June 2021

Bicarbonate concentration in saliva is controlled by the action of acid‐base transporters in salivary duct cells. We have previously shown expression of ATP6V1E1 and ATP6V1A in human and rodent salivary ducts and adaptive redistribution to the apical plasma membrane following acute and chronic metabolic acidosis. However, whether such redistribution has any physiological significance has not been elucidated. Using the human submandibular gland cell line HSG, we show for the first time functional expression of V‐ATPase in submandibular duct cells and introduce Transforming Growth Factor beta (TGF‐β) as a novel regulator of V‐ATPase subunits. Using QRT‐PCR, immunoblotting, biotinylation of surface proteins, immunofluorescence, and intracellular H(+) recording with H(+) ‐sensitive dye 2′,7′‐bis‐(carboxyethyl)‐5‐(and‐6)‐carboxyfluorescein, we show that activation of TGF‐β signalling upregulates ATP6V1E1 and ATP6V1B2, and has no effect on ATP6V1A. Following acidosis, neutralization of TGF‐βs or blocking of Smad2/3 phosphorylation decreased membrane expression of ATP6V1A, and prevented the acidosis‐induced increased V‐ATPase activity. The results suggest multiple modes of action of TGF‐β1 on V‐ATPase subunits in HSG cells: TGF‐β1 may regulate transcription or protein synthesis of certain subunits and trafficking of other subunits in a context‐dependent manner. Moreover, V‐ATPase is active in salivary duct cells and involved in intracellular pH regulation following acidosis.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.