bluuebunny/crossref_metadata_2025_split huggingface dataset:
NSAIDs inhibit Kv1.3 expression in IEC‐6 cells and rat duodenum (840.8)
Authors: Silver Kristopher , Marsh Elizabeth , Thomas Laurel , Littlejohn Alaina , Lillich James 
Published: June 2021

Clinical use of non‐steroidal anti‐inflammatory drugs (NSAIDs) is well known to cause gastrointestinal ulcer formation via several mechanisms that include inhibiting epithelial cell migration and mucosal restitution. The drug‐affected signaling pathways that contribute to the toxic side‐effects of NSAIDs are poorly understood. Previous studies have shown that NSAIDs inhibit cell migration in vitro by depolarizing membrane potential and suppressing expression of voltage‐gated potassium channel subunits. Kv1.3, in particular, is known to play an important role in cell migration, and results from a microarray study suggested that its expression is affected by NSAID treatment. Accordingly, we investigated the effects of NSAIDs on Kv1.3 mRNA and protein expression in a rat duodenal cell line (IEC‐6) or the duodenum of whole rats treated with indomethacin or NS‐398 for 72 h. Treatment of IEC‐6 cells with indomethacin or NS‐398 significantly reduced total and plasma membrane protein expression of Kv1.3. In rat duodenum, our results showed that expression of Kv1.3 mRNA was significantly decreased by NS‐398, but not indomethacin, and that Kv1.3 protein expression was significantly decreased following treatment with either NSAID. These results suggest that inhibition of epithelial cell migration by NSAIDs is associated with a decreased expression of Kv1.3 channels.Grant Funding Source: Supported by National Institutes of Diabetes and Digestive and Kidney Diseases (1R15DK091791)
Effects of the Gβ5‐RGS7 complex on muscarinic M3 receptor‐induced Ca2+ signaling and insulin secretion (843.12)
Authors: Slepak Vladlen , Karpinsky‐Semper Darla , Wang Qiang 
Published: June 2021

The G protein subunit Gβ5 forms obligatory heterodimers with regulators of G protein signaling (RGS) proteins of R7 family (RGS6, 7, 9 and 11). These complexes are expressed in neurons and glands. Previously, we showed that Gβ5‐RGS7 attenuated signaling downstream of muscarinic M3 receptor, M3R. A predicted consequence of Gβ5 ablation on pancreatic beta cells would be an increase in insulin secretion. However, we found that Gβ5‐R7 knockout strongly attenuated, while its overexperession in Min6 insulinoma cells enhanced M3R‐induced insulin secretion. We studied isolated mouse islets, transfected Min6 and CHO‐K1 cells, measuring insulin secretion and changes in intracellular Ca2+ in the presence of various pharmacological agents, muscarinic agonists and functional mutants of Gβ5‐RGS7 and M3R. The results showed that Gβ5‐RGS7 has a dual effect on M3R‐mediated Ca2+ transients. While it attenuated Ca2+ release from internal stores, it stimulated Ca2+ influx across the plasma membranes. This pathway involves Gq, PLC, TRP and L‐type like Ca2+ channels, and may be particularly important in regulating secretory activity in nerve terminals and glandular cells. We also found that distinct muscarinic agonists can not only bias M3R signaling to specific pathways, but also confer differential sensitivity to the Gβ5‐RGS7 complex.Grant Funding Source: Supported by National Institutes of Health (NIH) grants RO1EY018666 and RO1GM060019
Influence of M1 muscarinic acetylcholine receptor activation on arousal and cognitive performance using electroencephalography and novel touchscreen cognition assessment (845.5)
Authors: Gould Robert , Nedelcovych Michael , Dencker Ditte , Melancon Bruce , Stauffer Shaun , Wood Michael , Wess Jurgen , Xiang Zixiu , Lindsley Craig , Conn P , Jones Carrie 
Published: June 2021

Cognitive impairments associated with neuropsychiatric disorders such as Alzheimer’s Disease and schizophrenia remain largely untreated. Cholinergic hypofunction has been hypothesized to contribute to cognitive deficits yet the role of subtype‐selective muscarinic acetylcholine receptors (mAChR) remains unclear. Electroencephalography (EEG) studies demonstrated that the M1 mAChR partial agonist VU0357017 and positive allosteric modulator (PAM) BQCA induced wake‐promoting effects and a shift from low to high frequency power during wake suggesting enhanced arousal and a pro‐cognitive signature. Cognitive performance of M1 mAChR knockout (M1 KO) mice was examined across a series of computer touchscreen‐based pairwise discrimination tasks assessing susceptibility to interference from previously learned competing sets of information, a cognitive deficit present in neuropsychiatric disorders. M1 KO and wildtype mice acquired the initial discrimination at similar rates yet M1 KO mice showed impaired acquisition of subsequent discriminations. The current data demonstrate M1 mAChR mediation of susceptibility to interference following repeated learning, supporting development of M1 mAChR subtype‐selective compounds as pharmacotherapies for cognitive impairments associated with neuropsychiatric disorders.Grant Funding Source: Supported By MH086601, MH087965, MH093366, NS065867
Deletion of transient receptor potential canonical channel 1 prevents pulmonary vascular hyper‐permeability and edema formation secondary to cAMP activation of SPHK1 (847.4)
Authors: Tauseef Mohammad , Sukriti Sukriti , Ramaswamy Suresh , Dietrich Alexander , Birnbaumer Lutz , Malik Asrar , Mehta Dolly 
Published: June 2021

Transient receptor potential channel (TRPC1) mediates store operated calcium (Ca2+) (SOC) entry in response to endoplasmic reticulum (ER) store depletion by IP3, and thereby signals the loss of endothelial barrier function. We show that pulmonary endothelial cells isolated from TRPC1 null mice failed to increase cytosolic Ca2+ entry, endothelial gap formation and permeability in response to thrombin and thereby rendered the mice resistant to thrombin and thapsigargin‐induced lung vascular barrier dysfunction. cAMP as well as the lipid mediator sphingosine‐1‐phosphate (S1P) stabilize adherens junctions (AJs) and prevent lung vascular permeability and inflammation. Thus, we tested the hypothesis that TRPC1 deletion enhances endothelial barrier function through induction of cAMP and S1P signaling. Intriguingly, loss of TRPC1 in lung endothelial cells augmented sphingosine kinase1 (SPHK1) activity which induces the phosphorylation of sphingosine into S1P preventing AJs disruption. We show that EPAC but not PKA induced the activation of SPHK1 in human lung endothelial cells. EPAC activation enhanced endothelial barrier function in control cells but failed to strengthen barrier function in SPHK1 knockdown cells. Our results suggest that loss of TRPC1 deletion prevents increase in endothelial permeability through EPAC up regulation of SPHK1 activity. Thus, specific inhibitors design to target TRPC1 channel by increasing cAMP and S1P signaling may provide resistance to inflammatory pulmonary diseases such as acute lung injury and acute respiratory distress syndrome.Grant Funding Source: NIH
Implication of CD38/NAADP‐regulated autophagic flux in the phenotypic plasticity of mouse coronary arterial myocytes (849.3)
Authors: Wang Mi , Xu Ming , Chen Yang , Xia Min , Zhang Yang , Li Pin‐lan 
Published: June 2021

We recently reported that CD38 gene deletion inhibits lysosomes trafficking and fusion with autophagosomes (APs) leading to impaired autophagic flux in mouse coronary arterial myocytes (CAMs). However, the pathogenic role of this deranged autophagic flux due to CD38 deficiency remains unknown. Here, we showed that coronary arteries from CD38‐/‐ mice even on the normal diet exhibited marked profibrotic feature with increased collagen deposition compared to CD38+/+ mice. This collagen deposition in coronary arteries was significantly enhanced when CD38‐/‐ mice were fed a Western diet. In primary cultures of CAMs from CD38‐/‐ mice, a marked increase in the level of collagen I protein, but not mRNA was found in comparison with those cells from CD38+/+ mice either under control condition or upon TGF‐β stimulation. By treatment of CAMs from CD38+/+ mice with the inhibitor of CD38 enzyme, nicotinamide or the antagonist of CD38 product‐NAADP, NED‐19, the similar phenotypic changes in CAMs were observed to those cells from CD38‐/‐ mice. This action of CD38 inhibition and gene deletion was also similar to that observed when CAMs were treated by the inhibitor of the AP formation, 3‐methyladenine or the lysosome function disruptor, bafilomycin A1. However, inhibition of proteasome function by MG132 had no effects on increased collagen I levels in CAMs. Further confocal microscopy showed that enhanced collagen I deposition was mainly within lysosomes in CD38+/+ CAMs, which was blocked by CD38 gene deletion or NAADP antagonist, NED‐19. Collectively, we can draw a conclusion from these data that collagen I metabolism is disturbed when CAMs lack CD38 gene or if CD38‐NAADP‐mediated signaling pathway is dysfunctional, which may be associated with impaired autophagic degradation of collagen I. This CD38 regulation of autophagic flux may represent a novel mechanism regulating the phenotypic plasticity of CAMs upon atherogenic stimulation.Grant Funding Source: HL057244, HL091464 and HL075316
cAMP‐signaling regulates the expression of atheroprotective genes in vascular endothelial cells exposed to differential fluid shear stresses (851.14)
Authors: Rampersad Sarah , Hubert Fabien , Brzezinska Paulina , Freitag Silja , Umana M , Wudwud Alie , Maurice Donald 
Published: June 2021

Fluid‐mediated shear stress is an important, but often overlooked, mediator of vascular endothelial cell (VEC) health. VECs in the linear portions of macrovascular structures experience high laminar shear stress and exhibit an anti‐inflammatory and anti‐thrombotic phenotype. However, at vascular bifurcations and large curvatures fluid shear stress dramatically declines. Exposure to this low shear stress reduces VEC expression of vasculoprotective genes, making these areas preferential targets of atherosclerosis development. cAMP‐signaling is known to regulate a diverse array of VEC functions. Using various methodologies, we investigated the role of cAMP, and its downstream effectors, protein kinase A (PKA) and exchange protein activated by cAMP (EPAC)‐1, in regulating VEC health under differential fluid shear stresses. We report a novel role for cAMP, where modulation of this signaling pathway alters the expression of both atheroprotective and inflammatory genes in high and low shear stress conditions. This work has very important therapeutic implications for diseases characterized by endothelial cell dysfunction and atherosclerosis.Grant Funding Source: Canadian Institutes of Health Research
Label‐free proteomic analysis uncovers early molecular link to abnormal cardiac neurotransmission in pro‐hypertension rats (856.2)
Authors: Burton Rebecca‐Ann , Schmidt Carla , Lu Chieh‐Ju , Larsen Hege , Gallone Giuseppe , Li Dan , Hao Guoliang , Nikiforova Natalia , Bub Gil , Kramer Holger , Robinson Carol , Paterson David 
Published: June 2021

Sympathetic hyper‐responsiveness is an early hallmark of hypertension and has been linked to early metabolic and oxidative stress. We used label‐free quantitative proteomics to compare cardiac sympathetic neurons from the neonatal pro‐hypertensive rat (SHR) with neurons from an age matched normotensive control (WKY). Canonical protein interaction pathways and networks were generated using Ingenuity Pathway Analysis (IPA) to study protein regulation. We also performed functional association network analysis using STRING and the Girvan‐Newman fast greedy algorithm to produce protein clusters. Marked differences in proteins coupled to calcium signalling, metabolic processes, tissue architecture and cell migration were seen in the diseased neurons. In particular, we found abnormally high levels of non‐muscle myosin 9 in SHR neurons. This protein has been implicated in cytokinesis, vesicular trafficking, neurotransmitter release and familial human cardiovascular and neurological disease. Our findings indicate that direct modulation of myosin 9 could present a novel therapeutic target to manage abnormal sympathetic activation.Grant Funding Source: British Heart Foundation
Mitochondrial ROS generation and function in skeletal muscle from older subjects (863.5)
Authors: Sakellariou Giorgos , Lightfoot Adam , Pearson Timothy , Wells Nicola , Gilmore Alastair , Griffiths Richard , McArdle Anne , Jackson Malcolm 
Published: June 2021

Oxidative damage is reported to be involved in loss of tissue function with aging and the potential role of mitochondria as a source of increased ROS generation has been attributed to the impaired mitochondrial function and oxidative damage to mitochondrial components that occurs with advancing age. Data have predominantly been obtained from rodent studies and there is limited information on the role of mitochondrial ROS generation in muscle from older humans. To determine the role of mitochondrial ROS in the muscle decline that occurs with aging, muscle biopsies from young (20‐30 years) middle‐aged (45‐55 years) and older(>60 years) healthy volunteers were taken from the vastus lateralis muscle. Analyses were performed in small bundles of permeabilized fibers including mitochondrial ROS changes in the presence of various ETC substrates and inhibitors, changes in mitochondrial respiration, membrane potential and changes in maximum calcium‐activated tetanic force. No differences in fiber cross‐sectional area or force generation in response to calcium stimulation were observed in fibers between age groups. Respiratory function, mitochondrial membrane potential and ROS generation, assessed via changes in superoxide and hydrogen peroxide were not significantly different between age groups. Our data challenge the concept that mitochondrial ROS generation plays a key role in human skeletal muscle aging.Grant Funding Source: Funded by the Medical Research Council, UK (Grant No: G1002120)
Regulation of ion channels in cystic fibrosis (869.8)
Authors: Henry Katherine , Schiffhauer Eric , Lee Seakwoo , Zeitlin Pamela 
Published: June 2021

Cystic Fibrosis (CF) is an autosomal recessive disease, characterized by mutations in the CFTR gene, incorrect protein folding, and impaired chloride secretion. In addition to the maintenance of chloride secretion, CFTR is also suggested to be an important regulator of epithelial sodium channel (ENaC) activity. We previously identified the chloride channel ClCN2 as coexpressed with the mutant CFTR and hypothesized that in addition to restoring chloride secretion, ClCN2 can act as a negative regulator of ENaC. Coimmunoprecipitation analysis shows a novel physical interaction between ClCN2 and ENaC in pulmonary epithelium, which is accompanied by changes in ClCN2 and ENaC protein localization, as well as transepithelial resistance. Furthermore, ClCN2 has been shown to play an important role in the regulation of epithelial cell junctions and to this end, we show that changes in ClCN2 localization and activity may also affect cell junctions in CF cells. In conclusion, our data is the first to identify a novel interaction between ClCN2 and ENaC subunits. We also show potential changes in junction formation which may be regulated by changes in ClCN2 activity and localization. Therefore, when CFTR is nonfunctional, as in Cystic Fibrosis, ClCN2 may regulate ENaC activity and tight junction formation, which suggests that modulation of ClCN2 activity might be an advantageous target for treatment of the disease.Grant Funding Source: Supported by 5T32HL72748‐11: Ruth L Kirschstein National Research Service Award
Rostral ventrolateral medullary catecholaminergic neurons contribute to the hypoxic ventilatory reflex in unanesthetized rats (872.5)
Authors: Barna Bárbara , Damasceno Rosélia , Takakura Ana , Moreira Thiago 
Published: June 2021

The catecholaminergic (TH) neurons that reside in the rostral half of the ventrolateral medulla (VLM), also called C1 neurons, regulate blood pressure, the CRF/ACTH/corticosterone cascade and autonomic glucoprivic responses. The stimuli that most commonly activates the C1 neurons (nociception, hypotension, and hypoxia) also increases breathing. Although pharmacological evidence suggests that catecholaminergic neurons regulate breathing, a specific contribution of the C1 neurons to respiratory control has not been demonstrated, particularly in vivo. Here, we evaluate the role of the C1 cells in the control of breathing under hypoxia (8% O2) or hypercapnia (7% CO2) condition in unanesthetized rats. Bilateral injection of the immunotoxin anti‐dopamine β‐hydroxylase‐saporin (anti‐DβH SAP) was done in adult unanesthetized male Wistar rats (270‐300g, N = 5/group). Bilateral injections of anti‐DβH SAP (1.2 ng/100 nl) into VLM destroyed TH neurons. Selective inhibition of the C1 cells with bilateral injection of anti‐DβH‐SAP into the VLM reduced the increase in respiratory frequency (fR) (120 ± 8, vs. saline 136 ± 5 bpm), tidal volume (VT) (6.5 ± 0.4, vs. saline: 10.2 ± 2.7 ml/kg), and minute ventilation (MV) (818 ± 82, vs. saline: 1387 ± 325 ml/kg/min) elicited by hypoxia (8% O2). Hypercapnia challenges (7% CO2) caused graded increases in fR, VT, and MV, however, the changes in breathing elicited by hypercapnia was not altered after selective destruction of C1 cells in the VLM. The present study indicates that C1 neurons could be involved in the regulation of breathing and provide evidence that they may contribute to the hypoxic ventilatory reflex.Financial support: FAPESP, CNPq, CAPES/PROEX.Grant Funding Source: Supported by FAPESP, CNPq, CAPES/PROEX.
Contribution of the carotid body chemoreceptors to the modulation of heart rate variability (873.6)
Authors: Johnson Maja , Johnson Blair , Schlader Zachary , Crandall Craig , Joyner Michael 
Published: June 2021

We tested the hypothesis that administering low‐dose dopamine (2 mcg/kg/min) to desensitize the carotid body chemoreceptors would alter metrics of heart rate variability (HRV). Electrocardiogram (ECG) recordings were obtained from 18 healthy adults (age = 31 ± 2 years; BMI = 24.6 ± 0.6 kg/m2) during two randomized study days where they received an IV infusion of saline (S) or dopamine (DA). HRV was analyzed during five minute segments at baseline and during infusions of S and DA. Time‐domain analysis of the root mean square of the successive differences (RMSSD) along with spectral domain analysis of low (LF) and high frequency (HF) were obtained. There were no differences (P > 0.05) in respiration rate or blood pressure at any time point. Heart rate increased from baseline during DA (60 ± 2 vs. 63 ± 2 bpm; P < 0.01) and during infusion it was greater in DA vs. S (63 ± 2 vs. 58 ± 2 bpm; P < 0.01). RMSSD decreased from baseline to infusion during DA (68.2 ± 7.6 vs. 51.6 ± 6.0 ms; P < 0.01) and during infusion it was lower in DA vs. S (78.3 ± 10.3 vs. 51.6 ± 6.0 ms; P < 0.01). HF was reduced during DA vs. baseline (1733± 301 vs. 870 ± 171 ms2; P < 0.01), and during infusion DA was also lower than S (1936 ± 471 vs. 870 ± 171 ms2; P = 0.02). There were no changes (P > 0.05) in LF, LF/HF or normalized HF and LF values. These data indicate that during resting conditions the carotid body chemoreceptors likely modulate parasympathetic components of HRV in healthy adults.Grant Funding Source: Supported by NIH R01DK090541 and RO1HL61388
Aspirin augments carotid‐cardiac baroreflex sensitivity during muscle mechanoreflex and metaboreflex activation in older humans (875.8)
Authors: Drew Rachel , Blaha Cheryl , Herr Michael , Stocker Sean , Sinoway Lawrence 
Published: June 2021

Low‐dose aspirin augments carotid‐cardiac baroreflex (CBR‐HR) sensitivity during muscle mechanoreflex and metaboreflex activation in young humans. However, whether aspirin has a similar effect in older humans is unknown. Therefore, we examined the effect of inhibiting thromboxane (TX) A2 via low‐dose aspirin on CBR‐HR sensitivity during mechanoreflex and metaboreflex activation in older humans. Twelve older, healthy subjects (62±1y, 6 men) underwent 3min passive calf stretch (mechanoreflex) with limb occlusion after performing 1.5min 70% MVC calf exercise and post‐exercise circulatory occlusion for 3.5 min (metaboreflex). This occurred twice, after 7 days of either low‐dose (81mg) aspirin (Asp) or placebo (Pla). Asp decreased baseline TX B2 by 83±4% (P<0.05) but did not affect 6‐keto prostaglandin F1α. Resting CBR‐HR maximal gain (GMAX) was similar between Asp and Pla (‐0.18±0.05 vs. ‐0.25±0.05 b.min‐1.mmHg‐1 for Asp and Pla, respectively). CBR‐HR GMAX was significantly augmented during stretch and metabolite accumulation with Asp compared to Pla (‐0.22±0.03 vs. ‐0.15±0.02 b.min‐1.mmHg‐1 for Asp and Pla, respectively; P<0.05). These results suggest that low‐dose aspirin augments CBR‐HR sensitivity during muscle mechanoreflex and metaboreflex activation in older humans. This could be due to increased cardiac vagal activity caused by reduced TX sensitization of muscle mechanoreceptors.Grant Funding Source: Supported by NIH P01 HL096570 (LIS) and UL1 RR033184 (LIS).
Platelet levels and activity are decreased in hibernating 13‐lined ground squirrels which may prevent venous thromboembolism (879.17)
Authors: Cooper Scott , Howard David , Koch Tony , Lin Xingxing , Johnston Nate , Dobbs Kathryn , Zuberbuehler Matt , Cooper Amy , Lamont Christine , Mortimer Sarah , Hying Skyler , Bernhardt Kaley , Sell Shawn , Nelson Luke , Hawes Jennifer , Willems Heather , Morgan Leah , Macapugay Gizelle , Krus Catherine , Bowman Melissa , Lloyd Sarah 
Published: June 2021

The objective of this study is to determine how a hibernating mammal avoids the formation of blood clots under periods of low blood flow. Hibernating ground squirrels have dramatically decreased heart rates (3‐5 beats per minute) and blood flow, which should put them at risk of forming deep vein thrombi. In response, they have several adaptations during hibernation that prevent blood clotting, including 3‐fold decreases in Factors VIII and IX, and 10‐fold decreases in platelets. During hibernation, platelets are maintained at temperatures of 4‐8°C for up to six months. Within two hours of arousal, platelet levels return to normal, are not rapidly cleared from circulation, and are still functional. We have shown that in addition to decreased clotting factors, ground squirrels have a 10‐fold decrease in von Willebrand factor (vWF) protein and a 3‐fold decrease in vWF mRNA during hibernation. Platelets adhere to exposed collagen in a wound through binding to vWF, and unlike other mammalian platelets, cold storage of ground squirrel platelets does not increase binding of vWF. Ground squirrel platelets are also atypical in that their microtubules are cold‐resistant and change in shape from a circumferential ring to an equatorial rod once they reach 20ºC. This shape change was originally thought to trap the platelets in the spleen, but splenectomized and sham operated ground squirrels had the same platelet levels during torpor and interbout arousal, suggesting storage in an extrasplenic location. Finally, no evidence of irreversible cardiac ischemic damage was observed during hibernation through either histological staining or blood markers including troponin T, lactate dehydrogenase and creatine kinase. Taken together, these results suggest that ground squirrels avoid deep vein thrombosis by reversibly decreasing platelet levels and activity during hibernation.Grant Funding Source: Supported by NIH grant 2R15HL093680‐02