bluuebunny/crossref_metadata_2025_split huggingface dataset:
Properties of the high‐conductance Ca2+‐activated K+ (BK) channel in pulmonary arterial smooth muscle cells
Authors: Detweiler Neil , Song Li , McClenehan Samantha , Kharade Sujay , Kurten Richard , Rhee Sung , Rusch Nancy 
Published: June 2021

Pulmonary hypertension (PH) is associated with a loss of vasodilator influences in the pulmonary circulation, which results in pathogenic vasoconstriction. However, we observed an over‐expression of high‐conductance, Ca2+‐activated K+ (BK) channels in pulmonary arteries (PA) during chronic hypoxia (CH)‐induced PH, providing a potential vasodilator target. Here, we report that BK channels of PA smooth muscle cells (PASMCs) from CH rats retain high Ca2+‐sensitivity, α‐β1 subunit coupling that confers sensitivity to BK channel openers, and hypoxia‐insensitivity as compared to normal (N) rats (n=4‐11). Importantly, these properties may permit pharmacological activation of the BK channel even in a hypoxic environment. In inside‐out membrane patches used to record unitary BK currents in PASMCs from CH rats (n= 4‐7), the BK channel log(Ca2+ EC50(mol/L)) was ‐5.9 in both N and CH rats. Lithocholate (LCA), a BKβ1 subunit‐dependent opener, caused a 26‐fold and 19‐fold increase in BK channel open‐state probability in PASMC from CH and N rats, respectively. Using lung samples from organ donors without diagnosed PH, we also defined BK channel properties in human PASMCs. Similar to rat, the hBK channel exhibited high Ca2+‐sensitivity (log(Ca2+ EC50(mol/L)) = ‐6.1), was activated by LCA, and was not inhibited by acute hypoxia (n=4‐7). Thus, PASMCs from N and CH rats and humans without diagnosed lung disease express a β1 subunit‐coupled, hypoxia‐insensitive BK channel, which is responsive to BK channel openers.Supported by AHA 13PRE17240055 (NDD), NIH UL1RR029884 (NDD), and the UAMS College of Medicine Dean's Society.
Guttiferone K Exhibits Selective Cancer Cytotoxicity through ER Stress Aggravation
Authors: Miu Kai Kei , To Kenneth Kin‐Wah , Xu Hongxi , Lin Ge 
Published: June 2021

Guttiferone K (GutK) is a novel phytochemical that was previously reported to show selective cytotoxicity in cancer cells. This study aims to employ different human colorectal cancer (CRC) cell lines as models to confirm endoplasmic reticulum (ER) stress aggravation as the mechanism of GutK to cause apoptosis. Furthermore, normal colorectal epithelial cell line is adopted as a reference to understand how anti‐cancer selectivity occurs.ER stress markers were probed through immunoblotting and RT‐PCR in CRC cell line HCT116 and HT29 after treatment with GutK. Furthermore, prolonged treatment resulted in induction of pro‐apoptotic proteins, CHOP and DR5 expression. These protein were tested whether they could activate apoptosis by monitoring PARP cleavage after siRNA knockdown. Subsequently, realizing ER stress was aggravated by prolonged treatment with low dose of GutK in cancer cells, the same treatment was adopted on normal colon epithelial cell line CCD‐841 CoN to compare cytotoxicity via SrB assay, to check the ER stress state and to confirm selective toxicity through a normal & GFP‐labelled cancer cells co‐culture model by flow cytometry.ER stress activation was confirmed as a result of activation of GRP78 & GRP94, eIF2α and XBP‐1 mRNA splicing after GutK treatment. CHOP and DR5 were induced after prolonged treatment yet effects were abrogated after transfected with siRNA. Normal cells were spared after the same treatment, resulting in only a mild ER stress condition which was insufficient to initiate apoptosis.GutK aggravated ER stress in colorectal cancer cells but not in normal cells to elicit selective cancer cytotoxicity.
CRTC2 Contributes to PGC‐1α Expression in Skeletal Muscle Cells
Authors: Rahnert J , Zheng B , Hudson M , Woodworth‐Hobbs M , Price S 
Published: June 2021

Muscle wasting associated with chronic diseases has been linked to decreased expression of the transcriptional coactivator PGC‐1α. Overexpression of PGC‐1α can reduce FoxO‐mediated atrogene expression and counter muscle loss. Previous reports indicate that PGC‐1α transcription is regulated by CREB in a process that requires CREB‐regulated transcription coactivator (CRTC2). We recently found that CRTC2 protein is reduced in skeletal muscle of diabetic rats whereas CREB is highly phosphorylated (i.e., activated). Nuclear translocation of CRTC2 is promoted by dephosphorylation via calcineurin (CnA) while nuclear export occurs by phosphorylation via the salt‐inducible kinases (SIK). Our experiments tested the hypothesis that glucocorticoids decrease PGC‐1α expression, in part, by reducing CRTC2 levels in the nucleus. L6 myotubes were treated ± dexamethasone (Dex, 100nM) for 48hrs. Dex decreased PGC‐1α protein and nuclear level of CRTC2. It also decreased nuclear CnA and increased nuclear SIK, supporting the observed reduction in nuclear CRTC2 levels. Over‐expression of CRTC2 increased PGC‐1α protein and mRNA levels. To assess the role of CRTC2 on PGC‐1α transcription, muscle cells were transfected with a PGC‐1α luciferase reporter plasmid (PGC‐1α‐Luc). Over‐expression of CRTC2 increased PGC‐1α‐Luc activity. Dex decreased PGC‐1α‐Luc activity and deletion of the CRE binding site from PGC‐1α‐Luc (PGC‐1α‐DCRE‐Luc) attenuated the response. These data support the interaction of CRTC2 with phospho‐CREB as a mechanism for increasing PGC‐1α expression. Reduced nuclear CRTC2 may contribute to the loss of muscle mass arising during chronic diseases associated with elevated glucocorticoids.Supported by NIH RO1 DK95610, NIH T32 DK007656 and VA Merit X01BX001456
Chronic Hypoxia Attenuates cGMP‐dependent protein kinase (PKG)‐Mediated Vasorelaxation by Depressing BK Potassium Channel Activity in Cerebral Arteries
Authors: Thorpe Richard , Pearce William 
Published: June 2021

OBJECTIVEChronic hypoxia attenuates the ability of PKG to induce vasorelaxation in serotonin‐contracted ovine carotids, and more so in fetal than adult arteries. The present investigation examines the hypothesis that alterations in the BK channel and other PKG kinase substrates contribute to hypoxic attenuation of PKG‐dependent vasorelaxation in term fetal and adult ovine cerebral arteries.METHODSAdult and fetal sheep were maintained under normoxic (140±2 days at sea level) or hypoxic (140±2 days at 3820 meters elevation) conditions. PKG‐induced vasorelaxation was quantified by measuring changes in contractile force of middle cerebral artery segments using graded doses of serotonin in the presence or absence of the BK channel inhibitor iberiotoxin (100 nM) and/or the PKG activator 8‐pCPT‐cGMP (30 μM).RESULTSTotal PKG‐induced vasorelaxation was significantly less in hypoxic (8.9% fetal, 8.1% adult) than in normoxic (33.3% fetal, 26.3% adult) cerebral arteries. Corresponding values for BK‐independent PKG‐induced vasorelaxation were also less in hypoxic (6.3% fetal, 10.0% adult) than normoxic (28.7% fetal, 18.2% adult) cerebral arteries. For BK‐dependent PKG‐induced vasorelaxation, these values again were less in hypoxic (2.2% fetal, 1.8% adult) than normoxic (4.7% fetal, 8.1% adult) arteries.CONCLUSIONHypoxic attenuation of PKG‐induced vasorelaxation in ovine cerebral arteries was attributable to a reduced influence of PKG on the BK channel. Non‐BK channel mediators of vasorelaxation exhibited similar attenuation but of lesser magnitude. Fetal cerebral arteries were most affected by hypoxic stress.This work was supported by NIH Grants HL‐54120, HD‐31266, HL‐64867 and NS‐076945.
Effect of Desferroxamine Infusion on Cerebral Autoregulation in Elderly Individuals: A Randomized Placebo Controlled Trial
Authors: Purkayastha Sushmita , Sorond Farzaneh , Tan Can Ozan 
Published: June 2021

ObjectiveCerebrovascular disease results from chronic hypoxia induced by reduced perfusion. Animal studies have shown iron chelators such as desferroxamine (DFO) reduce brain damage and promote functional recovery after transient focal ischemia. The present study was designed to investigate the effects of DFO infusion on cerebral autoregulation (CA) in elderly individuals.MethodsNineteen volunteers (64±7 yrs) were enrolled in a randomized double‐blind placebo‐controlled crossover study. Subjects were randomized to either DFO or placebo (PLB) infusion for 9 hours. Arterial blood pressure and middle cerebral artery blood velocity were obtained using finger photoplethysmography and transcranial Doppler ultrasound for 5 min while subjects were seated upright at 0, 6 & 9 hours infusion. A non‐linear projection pursuit regression was used to examine the effectiveness of dynamic CA with DFO and PLB infusion.ResultsDecrease in gain (P=0.0341) within CA range was observed following 9 hours DFO compared to PLB suggesting effective CA although DFO infusion reduced the blood pressure range within which CA was effective compared to the PLB (P=0.004). The latter effect could be due to vasodilatation‐induced reduction in mean arterial pressure with DFO.ConclusionDFO infusion resulted in improvement in CA in elderly individuals and may be a potential therapeutic target for improving cerebral blood flow regulation.Research supported by K23AG030967 R01NS085002 (FAS)
Neurovascular Coupling Across the Menstrual Cycle
Authors: Davenport Margie , MacKay Christina , Skow Rachel , Steinback Craig 
Published: June 2021

Vascular function is modulated in response to the changing hormonal patterns of the menstrual cycle. Sex hormones may also act on non‐vascular cells regulating blood flow, including astrocytes and neurons, which may alter cerebral blood flow responses. However, the impact of menstrual phase on cerebral neurovascular coupling has not been investigated. We hypothesized that the visually evoked cerebral blood flow response would be higher in the mid‐luteal phase of the menstrual cycle, corresponding to elevated estrogen levels.Nine normally menstruating women (Age = 28 ± 6 yrs, BMI = 25 ± 4kg/m2) underwent a visual stimulation test in the early follicular (EF) and mid‐luteal (ML) phase of the menstrual cycle. Beat‐by‐beat mean arterial pressure (MAP) was derived using photoplethysmography (Finometer) and posterior cerebral artery blood flow velocity (PCAVP) was measured using transcranial Doppler ultrasound (Multigon).At rest, MAP (EF: 86.8 ± 7.4mmHg, ML: 87.7 ± 6.2mmHg, p=0.78) and cerebral blood flow (EF: 36.5 ± 5.5cm/s; ML: 37.6 ±11.3cm/s, p=0.80) were similar between phases. Further, the magnitude (EF: 25.0 ± 6.0%, ML: 26.5 ±8.5%, p=0.38) and the timing (EF: 12.0 ± 1.4s, ML: 11.8 ± 1.9s, p=0.78) of the cerebral blood flow response to visual stimulation was similar between phases.These data suggest that contrary to our hypothesis, neurovascular coupling assessed by visual stimulation was not different across the menstrual cycle. Supported by the University of Alberta ‐ Human Performance Scholarship Fund.
Cellular and Respiratory Responses to Inhalation of Traffic Derived Particles in a Rat Model of High Fructose Diet‐Induced Cardio‐Metabolic Syndrome
Authors: DIAZ EDGAR , Vasileios Papapostolou , Coull Brent , Harkema Jack , Godleksi John 
Published: June 2021

METHODSMale Sprague Dawley rats 250‐350g (Taconic Farms ‐ Rensselaer, NY), were fed for 8‐weeks prior to their first day of exposure with a high‐fructose diet (HFrD; 60% fructose by mass; TD.89247; Harlan Laboratories) to induce the metabolic syndrome phenotype, and continued on the diet until the end of the experiment. Animals were exposed to Aged Primary plus Secondary Organic Aerosol (P+SOA) tunnel emissions (Air Qual Atmos & Health 2013;6(2):419‐429). In all studies, control (Sham) exposures were conducted simultaneously.Animals were implanted with C50‐PXT blood pressure, temperature and ECG telemeters, Continuous respiratory data were collected at the time of exposure. Effects of each exposure were assessed using linear mixed models containing random animal effects and within exposure serial correlation in the form of a first‐order autoregressive process. In addition, we controlled for each day, so comparisons are between exposed and unexposed on a given day, with this difference related to the exposure level.RESULTSAverage exposure concentration was 20.41±6.18υg/m3.

Parameter
Δ Exp/Sham ± SE
p‐value

Systolic BP
6.40±3.31
0.055

Diastolic BP
5.01±2.28
0.030

Heart Rate
4.86±3.30
0.143

Frequency
7.30±1.27
<0.001

Tidal Volume
5.34±2.0
0.001

Inspiratory Time
‐9.56±5.33
0.078

Expiratory Time
‐35.73±9.89
<0.001

Peak Inspiratory Flow
1.57±0.36
<0.001

Peak Expiratory Flow
1.13±0.25
<0.001

CONCLUSIONSThe diet‐induced metabolic syndrome model was successfully produced with the high fructose diet. Our toxicological results for blood pressure outcomes behaved similar to our prior exposure with this aerosol in normal animals. Respiratory airflows differed suggesting parasympathetic influences, which had been observed with much higher exposure concentrations.
When Mbytes are not enough: long term, multiple channel, physiological telemetry implantable datalogger
Authors: Rotar Viorel , Pitsillides Koullis , Axelsson Michael 
Published: June 2021

Telemetry monitoring is an established tool that allows measurements from unrestrained animals and most telemetry systems for large animals have a typical range of less than 6‐8m in air. When an experimental design requires that instrumented animals are released into a large outdoor environment or mesocosm settings or when the animals are water living or have an amphibious lifestyle, this precludes the use of an RF link to transfer the implanted data to the computer and requires local storage means such as a datalogger.We have developed an implantable, low power datalogger that interfaces directly to a bio‐telemetry system (EG1‐V2S3T, Transonic EndoGear Inc). The datalogger has the capacity to store up to 6 channels of data at 100 Hz which results in about 125MB/day of continuous data. The datalogger has a capacity of 8GB and is capable of continuous operation for over 8 weeks. Datalogging is controlled via the same computer interface controlling the implant and can be started either during implantation or at a later stage after post‐surgical recovery period before the animals are released from the lab environment.These dataloggers were field tested in six crocodiles (apprx. 22‐42kg, 1.4 ‐2.2m long) instrumented with the EG1‐V2S3T implants for blood flow, pressure, ECG and temperature and connected to a datalogger (Model EG1‐DTL). The animals were released in a mesocosm setting at Mongena Game Reserve in South Africa and were allowed to remain undisturbed for 4 weeks. Video cameras were used to correlate physiological data with behavioral data and external time depth recorders were used to monitor diving events.
Rho‐kinase Mediates Biventricular Coronary Arterial Remodeling During Pulmonary Arterial Hypertension in Fischer 344 Rats
Authors: Crockett Edward , Stevens Troy , McMurtry Ivan 
Published: June 2021

Rationale: Fischer 344 rats exposed to Sugen‐5416 and hypoxia, then normoxia (Su/Hx/Nx) develop severe pulmonary arterial hypertension (PAH). Unique to this strain, PAH is accompanied by significant death within 8 weeks. Coronary remodeling and acute heart failure is suspected. Here, we test the hypothesis that PAH is accompanied by biventricular Rho‐kinase mediated coronary arterial remodeling, ischemia and heart failure. Methods: Rats were injected with Sugen‐5416 followed by 3 weeks of hypoxia (10% O2), then 6 weeks of normoxia (21% O2). Survival was plotted as a Kaplan‐Meier curve. Histology examined biventricular coronary remodeling and matrix deposition. Hypertensive rats were treated with fasudil, a Rho‐kinase inhibitor, added to the drinking water. Preliminary Results: 3 out of 4 non‐treated PAH rats died between 5 and 8 weeks of Su/Hx/Nx exposure, while 3 out of 3 fasudil‐treated PAH rats survived to 9 weeks, when sacrificed. Echocardiography at 5 weeks showed right ventricular dilation, septal deviation and decreased cardiac output. RV/(LV+S) confirmed significant hypertrophy of the right ventricular wall regardless of treatment. Histology revealed that Rho‐kinase inhibition normalized biventricular coronary remodeling and perivascular fibrosis (Figure 1). ConclusionDuring PAH in Fischer rats, Rho‐kinase mediates coronary arterial wall thickening in both ventricles, which primes the heart for ischemia and failure.Funding: NIH‐ HL060024 and HL066299
Figure 1: Coronary arteries during PAH with or without fasudil treatment compared to normotensive. Red arrows‐ smooth muscle medial hypertrophy; yellow star‐ perivascular fibrosis.image
Changes in Endothelial Cell Membrane Morphology and Elasticity with Exposure to Polyunsaturated Free‐Fatty Acids
Authors: Mabry Brittany , Lau Elese , Hunt Brian 
Published: June 2021

BackgroundThe purpose of this preliminary study is to determine the effect of incubating human endothelial cells in PUFA's on their nanomechanical properties.MethodsHuman aortic endothelial cells (Invitrogen) were cultured in endothelial cell medium containing fetal bovine serum, growth supplement and penicillin/streptomycin (ScienCell Research Laboratories) and incubated in the presence of 5% CO2 at 37°C for 24 hours. Cells were then incubated for another 24 hours in medium containing either 400 mM cholesterol, normal cell medium, or 400 mM docosahexaenoic acid (DHA), or eicosapentanoic acid (EPA). Differences in membrane morphology and elasticity were measured using atomic force microscopy (AFM; Bruker BioScope) in cell medium at room temperature. Data were analyzed using NanoScope.ResultsCells incubated in in EPA or DHA were flatter (height =2667nm and 2372 nm respectively) compared to control cells (3141nm) and cholesterol cells (height = 5390nm). The elastic modulus of DHA‐incubated cells (3.63 log(Pa)) differed compared to control cells (3.95 log(Pa)) and cholesterol cells (4.14 log(Pa)). Deformation also differed between DHA cells (323 nm) and cholesterol cells (249 nm).ConclusionPUFA incubated cells differ in their nanomechanical properties compared to control and cholesterol cells, as measured by AFM. Measures of elastic modulus and deformation suggest a more fluid membrane in PUFA incubated cells, which may enhance glucose uptake in these cells.
Impact of Moderate Zinc Deficiency During Fetal Life and Postnatal Growth on Cardiac Nitric Oxyde System, Inflammatory and Oxidative Markers in Adult Male Rats
Authors: Juriol Lorena , Gobetto Natalia , Mendes Garrido Facundo , Pineda Gonzalo , Dasso Marina , Toblli Jorge , Carranza Andrea , Elesgaray Rosana , Tomat Analía , Arranz Cristina 
Published: June 2021

Moderate zinc deficiency during fetal and postnatal growth programs cardiovascular dysfunction and hypertension. Male zinc deficient rats showed reduced left ventricular (LV) wall thickness and ejection fraction. Aim: to evaluate nitric oxide (NO) system, pro‐inflammatory cytokines and oxidative state in LV of adult male rats exposed to this deficiency. Wistar rats received during pregnancy up to weaning low (L:8 ppm) or control (C:30 ppm) zinc diet. After weaning, male offspring fed low (l) or control (c) zinc diet during 60 days (Cc, Ll, Lc). At day 81, we evaluated in LV: Interleukin‐6 and Tumor Necrosis Factor‐α (IL‐6;TNF‐α), basal NO synthase (NOS) and endothelial, neuronal and inducible (eNOS;nNOS;iNOS) isoforms activities; eNOS and Ser1177 eNOS phosphorylation protein expression (eNOS/β‐actin; pSer1177eNOS/eNOS), mRNA expression (eNOS/GAPDH) and lipid peroxidation end products (TBARS). Means±SEM, n=6/group. One way ANOVA, Bonferroni post‐test.

Cc
Ll
Lc

TNF‐α (immunohistochemistry;% of positive staining/area)
1.4±0.4
20.4±2.0*
1.7±0.3

IL‐6 (immunohistochemistry; % of positive staining/area)
1.8±0.3
21.1±1.7*
2.8±0.8

Basal NOS Activity (pmol14C L‐citrulline/g tissue.min)
204±6
164±10*
157±11*

Basal NOS+iNOS inhibitor (Aminoguanidine; pmol14C L‐citrulline/g tissue.min)
216±7
166±8*
163±9*

Basal NOS+nNOS inhibitor (7‐nitroindazole; pmol 14C L‐citrulline/g tissue.min)
209±10
166±8*
164±9*

Basal NOS+Ca2+‐calmodulin inhibitor (Calmidazolium; pmol 14C L‐citrulline/g tissue.min)
47±2#
52±2#
49±2#

pSer1177eNOS/eNOS (Western Blot; optical density relative to Cc)
1.00±0.02
0.74±0.03*
1.02±0.16

TBARS (nmol/mg protein)
0.21±0.02
0.78±0.08*
0.47±0.02*†

No differences were found in eNOS protein and mRNA expression.*p<0.01vsCc;†p<0.01vsLl;#p<0,01vs basal NOS.Zinc deficiency during fetal and postnatal life programs a lower production and bioavailability of cardiac NO due to decreased activity and pSer1177 of eNOS and increased TBARS. These alterations, jointly with higher levels of IL‐6 and TNF‐α, could contribute to the cardiac disorders previously observed. Supported by:UBA‐CONICET
Anti‐Hypertrophic Effect of Estradiol in Cardiomyocytes is Mediated by GPER1
Authors: Gonçalves Gleisy , Nocchi Eduardo , Scalzo Sergio , Guatimosim Silvia , Reis Adelina 
Published: June 2021

Previous data have shown that E2 prevents cardiomyocyte hypertrophy induced by endothelin‐1 (ET‐1) and Angiotensin II, acting through the increase of atrial and type‐B natriuretic peptides (ANP and BNP) levels. In recent years, a membrane‐bound E2 receptor has emerged, G protein‐coupled estrogen receptor 1 (GPER1), which mediates many estrogenic effects. In this work, we investigated whether E2 protective signaling effect on ET1‐induced hypertrophy is mediated via GPER1 receptor. Newborn rat cardiomyocytes were isolated and cultured in DMEM supplemented with 10% fetal bovine serum with antibiotic and antimycotic. Cells were treated for 48h with ET‐1 (10 nM) in the presence or not of E2 (10 nM). In some experiments GPER1 antagonist (G15, 10 nM) was added to the medium. ET‐1 induced an increase in cardiac myocyte area compared to control group. Treatment with E2 partially inhibited the hypertrophic effect of ET‐1. Treatment with G15 reversed antihypertrophic effect of E2. Moreover, ET‐1 upregulated ANP and BNP levels, an effect that was abolished by E2. G15 prevented the decrease of BNP but not ANP in cardiomyocytes treated with E2 in the presence of ET‐1. ET‐1 treated cells showed increased translocation of GRK5 to the nucleus and this effect was abolished by E2. The reduction of the contraction frequency and increase of contraction force observed in the ET‐1 group were reversed by E2. In conclusion, E2 plays a key role antagonizing the hypertrophy induced by ET1 and this effect was mediated by GPER1.Financial Support: CNPQ, CAPES, FAPEMIG