bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanism of inhibition of delayed rectifier K+ current by diphenyl phosphine oxide‐1 in porcine coronary smooth muscle (1079.10)
Authors: Fancher Ibra , Noblet Jillian , Goodwill Adam , Tune Johnathan , Dick Gregory 
Published: June 2021

Mechanisms involved in DPO‐1‐induced block of KDR were studied in myocytes isolated from the porcine coronary artery. DPO‐1 inhibited the slowly inactivating KDR in a dose‐dependent manner (IC50 = 212 ± 28 nM). Neither the time constant of activation (+20 mV) nor the time constant of deactivation (‐40 mV) was affected by DPO‐1 (1 μM). However, the fast and slow time constants of inactivation at +20 mV were notably shortened by DPO‐1 (fast = 0.52 ± 0.07 vs. 0.14 ± 0.01 s; slow = 5.8 ± 1.1 vs. 0.6 ± 0.2 s). These results suggest that DPO‐1 preferentially binds to the channel in the open state, producing an open channel block of KDR. As such, if KDR channels were open under resting conditions in vascular smooth muscle, then DPO‐1 should depolarize the membrane potential and cause vasoconstriction. To test this hypothesis and show functional relevance, we determined the effect of DPO‐1 on the membrane potential and coronary blood flow. DPO‐1 depolarized membrane potential from –29 ± 1 to ‐14 ± 3 mV. Further, DPO‐1 reduced coronary artery blood flow at 100 mmHg perfusion pressure from 21 to 14 ml/min. Together, these data indicate that DPO‐1 blocks KDR channels in the open state and that KDR channels in vascular smooth muscle are open under resting conditions. Thus, therapeutic tools that target KDR activity could be used to regulate vascular tone and mechanisms controlling KDR merit further study.Grant Funding Source: Supported by T32HL090610, T32HL079995, AHA 13POST1681001813, HL092245
Thymoquinone protects against myocardial ischemia‐reperfusion injury via modulation of oxidant generation and nuclear factor‐kappaB‐mediated responses (1080.1)
Authors: El‐Mahdy Mohamed , Ismail Raed , Hemann Craig , El‐Sherbiny Gamal , Abdelghany Tamer , Helal Gouda , Zweier Jay 
Published: June 2021

Understanding the mechanisms of natural compounds in modulating disease has moved to the forefront of cardiovascular research. Thymoquinone (TQ), a constituent of the volatile oil derived from Nigella sativa seeds, has demonstrated promising effects against ischemia‐reperfusion (IR) injury of different organs; however, the mechanism of TQ action on myocardial IR injury (m‐IRI) warrants more investigation. Rat hearts were either subjected to 30 min of global ischemia followed by 120 min of reperfusion using a Langendorff system, or to 30 min of left anterior descending coronary artery (LAD) ligation followed by 24h of reperfusion. TQ was infused ex‐vivo for 10 min either pre‐or post‐ischemia or IP‐injected for seven days prior to the surgery. TQ significantly reduced reactive oxygen species (ROS) generation, infarct size and apoptosis, and markedly enhanced coronary flow and ventricular function of the ischemic hearts. TQ attenuated the IR‐induced up‐regulation of SAPK/JNK, myocardial nuclear factor (NF)‐kappaB, TNF‐α, and P38‐MAPK expression and increased the Bcl‐2/Bax ratio. The data indicate that TQ inhibited ROS generation‐induced NF‐kappaB which led to inhibition of pro‐inflammatory cytokines and apoptosis, protecting the heart against IR injury. This study presents a new molecular mechanism of action and efficacy of TQ with promise as a natural compound in the management of m‐IRI.Grant Funding Source: NIH# 00000784 & Egyptian Government
Female spontaneously hypertensive rats have a compensatory increase in renal regulatory T cells in response to elevated blood pressure (1083.3)
Authors: Tipton Ashlee , Li Beverly , Sullivan Jennifer 
Published: June 2021

We recently demonstrated that female SHR have more anti‐inflammatory regulatory T cells (Tregs) in their kidneys than males. The goal of this study was to determine the impact of blood pressure (BP) on Tregs in male (M) and female (F) SHR. We hypothesized that hypertension (HTN) promotes renal T cell infiltration in both sexes, although females will have greater increases in Tregs. SHR were treated with hydrochlorothiazide and reserpine from 6 to 13 wks of age (7‐HCTZ), 11 to 13 wks of age (2‐HCTZ), or vehicle control (N=5‐8) and renal T cells were measured by flow cytometry. 7‐HCTZ attenuated age‐related increases in BP (M: 137±4, F: 132±4 systolic BP mmHg) and 2‐HCTZ reversed established HTN (M: 122±4, F: 116±3 mean arterial BP mmHg; p<0.05) compared to vehicle‐treated SHR (M: 174±4, F: 161±1 mean arterial BP mmHg). Neither 7‐HCTZ nor 2‐HCTZ altered renal CD3+ or CD4+ T cell infiltration in either sex. Both treatments decreased renal Tregs in female SHR (vehicle: 11±0.2 vs 7‐HCTZ: 6±0.4 %CD4+CD3+ cells, p<0.05; vehicle: 9±0.5 vs 2‐HCTZ: 3±0.6, p<0.05); Tregs in males were unaffected. F SHR maintained greater Treg infiltration than males following 7‐HCTZ treatment (males: 7±1 vs females: 6.4±0.4; p<0.05). Treg infiltration was comparable in 2‐HCTZ‐treated M and F SHR (Tregs males: 5±1 vs females: 3.2±0.6, NS). These data suggest that female SHR have a compensatory increase in renal Tregs in response to increases in BP.Grant Funding Source: Supported by Intramural Funds
Post‐exercise fate of lactate in the American locust (1101.2)
Authors: Tyler Samantha , Olson Matthew , Kirkton Scott 
Published: June 2021

The fate of lactate after exercise varies between animal groups. Mammals oxidize lactic acid in their muscles, fish oxidize lactic acid in their liver, and reptiles use both their muscles and liver to oxidize post‐exercise lactate. Grasshoppers are unique among insects in that they produce lactic acid during repeated jumping. However, it is unclear where the lactate is oxidized. Using the American locust (Schistocerca americana), we measured lactate levels in the jumping muscle at different time points after jumping. Lactate levels were measured using a fluorometric plate assay. Immediately after three minutes of jumping, muscle lactate levels were approximately 23 mmol kg‐1. After fifteen minutes of rest, lactate levels decreased by 40% in the jumping muscle. After one hour of rest, muscle lactate levels had decreased by 70% of their post‐exercise level. After approximately three hours of rest, muscle lactate was similar to pre‐jumping levels. We have previously demonstrated that lactate production correlates with jumping fatigue rate in S. americana grasshoppers. Current work is examining whether hemolymph or fat body lactate levels vary after jumping. A decrease in muscle lactate levels during recovery, combined with a rise in hemolymph and fat body lactate levels would suggest a non‐muscle model for lactate oxidation in grasshoppers.Grant Funding Source: Supported by Union College Undergraduate Research Grants
Thyroid hormone changes associated with prolonged food deprivation in adult male northern elephant seals (1101.6)
Authors: Lee Debby , Martinez Bridget , Crocker Daniel , Ortiz Rudy 
Published: June 2021

During food deprivation in mammals, thyroid hormone (TH) concentrations and deiodinase (DI) content is typically reduced to suppress metabolism. However, in metabolically active elephant seal pups the hypothalamic‐pituitary‐thyroid axis is up‐regulated during prolonged fasting. To better understand the mechanisms regulating the cellular function of TH in a fasting, yet metabolically active mammal, we measured plasma TH concentrations and mRNA expressions of DI type II (DI2) and TH receptor beta‐1 (THrβ‐1) in adult male northern elephant seals (n=8) over 8 weeks of fasting (early vs. late). We hypothesized that natural fasting in male seals decreases TH levels and DI expression. Fasting did not alter the concentrations of plasma reverse T3 and total T4. However, free T4 (0.25 ± 0.03 to 0.78 ± 0.08 ng/dL) and free T3 (0.61 ± 0.06 to 0.83 ± 0.08 pg/mL) increased between early to late fasting suggesting that there is an increased potential for TH‐mediated cellular effects. Conversely, total T3 decreased (63 ± 5 to 50 ± 4 ng/mL) suggesting that DI2 or DI3 may be contributing to the changes in TH metabolism. mRNA expressions of DI2 and THrβ‐1 decreased 87% ± 7 and 93% ± 2, respectively, between early to late fasting suggesting that there is a down‐regulation in cellular TH potential during fasting duration consistent with the effects of fasting in other mammals. When compared to the opposite effects observed in fasting pups, we conclude that elephant seals have evolved age‐dependent changes in fasting‐induced TH dynamics that may reflect differences in TH‐associated metabolic mechanisms.Grant Funding Source: Supported by NIH/NHLBI 442606‐RO‐29013
Differential effects of clonidine and lisinopril on thermoregulatory and cardiovascular function during chronic exposure to exertional heat stress in rats (1104.30)
Authors: Stauss Harald , Choudhary Navita , Moss Anne , Kregel Kevin 
Published: June 2021

The effects of clonidine (C, sympatholytic drug) and lisinopril (L, ACE inhibitor) on thermoregulatory, cardiovascular, and autonomic responses to chronic (5 days, 2 times/day) exertional (ExHS) or non‐exertional (HS) heat stress were assessed in rats. ExHS and HS elicited increases in nocturnal core temperature (Tc) and heart rate (HR) in placebo (P) treated rats. This effect was blunted by C in the ExHS protocol and by both drugs in the HS‐only protocol. Nocturnal blood pressure (BP) increased more during the ExHS than the HS protocol. This hypertensive response to ExHS was blunted by both drugs. In P‐treated rats, baroreflex sensitivity decreased only during the ExHS protocol. L improved this impaired baroreflex function during exposure to ExHS more than C. In P‐treated rats, sympathetic modulation of cardiac and vascular function (low frequency HR and BP variability) was elevated in both protocols. Both drugs reduced this elevated sympathetic modulation of cardiovascular function. In conclusion, C and L elicited beneficial thermoregulatory (Tc), cardiovascular (BP, baroreflex function), and autonomic (cardiac and vascular sympathetic modulation) effects during exposure to HS or ExHS. However, during exposure to ExHS, C appears to be more effective in improving thermoregulation than L, while L may be more effective in improving cardiovascular (baroreflex) function than C.Grant Funding Source: Supported by DoD/USAMRMC #W81XWH‐10‐2‐0115.
Increased expression of caveolin‐1 is associated with upregulation of the RhoA/Rho kinase pathway and smooth muscle contraction in diabetes (1110.11)
Authors: Mahavadi Sunila , Nalli Ancy , Kumar Divya , Bhattacharya Sayak , Zhou Ruizhe , Grider John , Murthy Karnam 
Published: June 2021

Gastrointestinal motility disorders are common among type I and type II diabetes and are shown to be associated with depletion of ICC and NOS‐containing neurons. Our recent studies in smooth muscle of diabetic mice and diabetic patients showed that hyperglycemia causes upregulation of RhoA/Rho kinase pathway leading to increase in sustained muscle contraction (tone). Caveolin‐1, an essential protein in the formation of caveolae, positively regulates RhoA/Rho kinase pathway in smooth muscle. Aim. To test the hypothesis that increase in caveolin‐1 expression causes upregulation of the RhoA/Rho kinase pathway in diabetes. Results. mRNA and protein expression of caveolin‐1 was increased in gastric smooth muscle from type 1 (NOD) and type 2 diabetic (db/db) mice and from diabetic patients. Treatment of muscle cells from control mice with 25 mM glucose for 48 h increased expression of caveolin‐1 and augmented ACh‐induced Rho kinase activity. The effect of high glucose on caveolin‐1 expression and Rho kinase activity was reversed by 72 h treatment in 5 mM glucose. Suppression of caveolin‐1 by siRNA attenuated the effect of high glucose on Rho kinase activity, whereas overexpression of caveolin‐1 in control cells augmented ACh‐induced Rho kinase activity. Conclusion. Increased expression of caveolin‐1 in smooth muscle contributes to upregulation of the RhoA/Rho kinase pathway and sustained contraction in diabetes.Grant Funding Source: DK28300 and DK15564
Circadian clock mediates ER stress signaling in alcoholic fatty liver (1116.12)
Authors: Tsuchiya Hiroyuki , Zhang Yuxia , Lee Sangmin , Smalling Rana , Wang Li 
Published: June 2021

[Purpose] This is the first study to investigate how alcohol regulates ER stress and fatty liver through nuclear receptor SHP mediated liver circadian clock machinery.[Methods] The NIAAA EtOH binge model was established using 8 weeks old, male C57BL/6 (WT) and SHP‐/‐ (SKO) mice (Nat Protoc 2013; 8:627‐637). In brief, the mice were acclimatized to a control liquid diet for 5 days, then fed with 5% Lieber‐DeCarli diet or pair‐fed for 10 days. By day 11, the mice were gavaged maltose (control) or EtOH solutions at zeitgeber time (ZT) 3 (9 am) and sacrificed at ZT12, 18, 0, and 6.[Results] Metabolomics by GC/MS revealed a global alteration by alcohol in the oscillation of serum intermediate metabolites in pathways of glucose, lipid and amino acid metabolism in SKO mice. The rhythmic expression of core clock genes (Clock, Bmal1, Npas2) and nuclear receptors (Rorα, Rorγ, Rev‐erbα) were disturbed by alcohol. Hepatic lipid metabolic genes and ER stress markers exhibited strong oscillations which were perturbed by alcohol. Chop was a clock controlled gene through the Rorα/Rorγ/Rev‐erbα/SHP regulatory cascade. Liver SREBP‐1c protein cleavage and TG content were drastically induced in control SKO livers, which was markedly decreased by alcohol in both WT and SKO mice.[Conclusions] SHP mediated clock machinery is significantly disrupted by alcohol, which in turn perturbs ER stress to control AFL.Grant Funding Source: Supported by AHA and NIDDK
Global DNA methylation and extracellular matrix remodeling in aortic smooth muscle versus endothelial cells in hyperhomocysteinemia (1120.5)
Authors: Narayanan Nithya , Kundu Sourav , Givvimani Srikanth , Pushpakumar Sathnur , Kulkarni Ruhi , Tyagi Suresh 
Published: June 2021

Introduction: Homocysteine (Hcy) is a byproduct of DNA methylation. Increased levels of Hcy (HHcy) have been shown to induce smooth muscle cell (SMC) proliferation and inhibit endothelial cell proliferation. It is well known that HHcy causes increased activation of matrix metalloproteinases, a key factor in vascular remodeling. However, the role of global DNA methylation in regulating aortic matrix remodeling is not known.Hypothesis: In the present study, we hypothesize that global DNA methylation during HHcy regulates the expression of MMPs in mouse aortic SMCs and endothelial cells (MAEC).Methods: Mouse SMC and MAEC were cultured with 80µM Hcy and 100µM Aza deoxycytidine (AzadC), DNA methyltransferase inhibitor.Results: Global DNA methylation analysis by ELISA showed that in HHcy, there was a 2 fold and 1.3 fold increase in %5‐mC in SMC and MAECs respectively. During HHcy, there was an increased expression and activity of MMP9 in SMCs, which depreciated after AzadC treatment. Methylation Specific PCR (MS‐PCR) showed increased methylation status of Hcy metabolism genes, CBS and MTHFR in SMCs and MAECs.Summary: Our results suggest that HHcy causes a greater global hyper‐methylation in aortic SMC than in MAEC. This may suggest that Hcy generated through methylation contributes to vascular remodeling.Grant Funding Source: NIH
Prolactin influences the excitability of subfornical organ neurons (1129.3)
Authors: Black Emily , Grattan Dave , Ferguson Alastair 
Published: June 2021

Prolactin is a hormone that is involved in multiple physiological functions in vertebrates. Prolactin receptor mRNA has been identified in the subfornical organ (SFO) through microarray analysis (Hindmarch et al 2008). The current study was therefore carried out in order to determine the effects of prolactin on the excitability of SFO neurons. We used the whole‐cell patch clamp technique to determine the influence of prolactin on the membrane potential of dissociated SFO neurons. We found that 55% (11 of 20) of neurons responded when treated with prolactin (1 uM and 100nM). Of the cells that responded, 54% (n=6) depolarized with a mean depolarization of 7.7 ± 3.3 mV and 46% (n=5) hyperpolarized with a mean hyperpolarization of ‐8.0 ± 3.6 mV. This study suggests the SFO as a potential central nervous system site at which prolactin may act to influence central autonomic integration.Grant Funding Source: Canadian Institutes for Health Research
Female mice retain more sodium than male mice but maintain lower blood pressure during 30 days on a high salt diet (1135.1)
Authors: Rouch Al , Kudo Lucia , Fan Liming , Hammami Heba , Nadeem Maria , Chatzigiannidis Athena 
Published: June 2021

High salt consumption contributes to hypertension. The kidneys must excrete ingested sodium in order to maintain normal blood pressure. Our previous study showed that female mice had lower renal excretion of sodium (Nae) than male mice for a 15‐day period of high salt consumption. The goal of this study was to determine if sex differences in Nae and blood pressure (BP) occur from a 30‐day period of high salt consumption. Intact female and male 12‐week old mice (n=6/group) consumed a 4% salt diet in metabolic cages for 30 days. Nae was determined from daily measurements of urine sodium concentration and urine volume. Sodium intake (Nai) was determined from daily food intake. BP was measured via the tail‐cuff method. Real‐time quantitative PCR was used to measure expression of renal sodium transporters. For the 30‐day period, average daily Nae/Nai (%) was significantly lower in female mice compared to male mice (53.3±2.7 vs 68.1±1.8, respectively, p<0.0001) in addition to the mean BP (mmHg) (78.4 ±1.0 vs 84.9 ±1.2 respectively, <0.0005). Expression of the renal NKCC2 mRNA was over 5‐fold higher in the female kidney. We conclude that female mice retain more sodium and maintain lower BP during high salt consumption compared to male mice. This study indicates that female mice exposed to a high salt diet are protected from hypertension for a period of 30 days despite higher sodium retention.Grant Funding Source: Supported by OK INBRE 8P20GM103447 Summer Research Program
Impact of uninephrectomy on body L‐arginine homeostasis and blood pressure control (1136.14)
Authors: Pillai Samyuktha , Fingerhut Ralph , Verrey François 
Published: June 2021

L‐arginine plays an important role, acting as a precursor for a variety of physiologically important substances including citrulline, urea, ornithine, proline and nitric oxide and the kidney is a major site for its metabolism. Uninephrectomy (UNX) is observed to cause an increase in the size of the remnant kidney and compensation to some degree of the glomerular filtration rate. As very little is known about UNX‐induced effects on blood pressure control and expression levels of transporters and enzymes involved in arginine metabolism, we are testing in mice the hypothesis that renal mass reduction impacts on Arg metabolism and possibly thereby affects blood pressure control. Our results show that in contrast to sham operated controls, mice having undergone UNX display an increased systolic blood pressure (120 ± 2.14 vs. 112 ± 1.97 mmHg by tail cuff measurements, n = 18). This effect was more pronounced in females than males and observed also by telemetry. Plasma levels of asymmetric dimethyl arginine (ADMA), an inhibitor of NOS considered to be a good marker for renal disease, were increased in UNX animals, whereas the level of none of the proteinogenic amino acids was changed significantly. There were also no changes in the mRNA expression levels of Arg transporters and enzymes involved in arginine metabolism. Our observations suggest that UNX affects blood pressure and the effects are less pronounced in males, possibly due to a more important remnant kidney compensatory growth.Grant Funding Source: Supported by the Swiss NCCR Kidney.ch and the European Community's Seventh Framework Programme
Chromosomal mapping and zygosity check PCR of transgenes in a GFP mouse line (C57BL/6‐Tg(CAG‐EGFP)C14‐Y01‐FM131Osb) determined by genomic walking (1138.13)
Authors: Suzuki Osamu 
Published: June 2021

Positional effect of transgenes is important for analyses of transgenic animals. In this study, the transgene insertion site in genomes of a GFP mouse line and primers for zygosity check PCR were determined by genomic walking (Exp Anim 53:103‐111, 2004). Adapter‐ligated, enzyme‐restricted genomic libraries were constructed with genomic DNA from hemizygous GFP mice. The sequence flanking the transgene was determined by sequencing amplicons from PCR of the genomic libraries with transgene‐specific and adaptor primers. The insertion site was located by BLAST search in Ensembl genome database (http://www.ensembl.org) using the genome sequence flanking the transgene. Primer sets for zygosity check were designed based on the transgene and flanking genome sequences. The flanking sequence was mapped on chromosome 11. Three primers were designed for zygosity check (1: CACCGCCGGGTCTCTCACTGTCAGTCT, 2: GACGTCAATGGGCGGGGGTCGTT, and 3: TGGGACCTGATCACGGTAAAACGAGGT). Transgenic and wild alleles could be detected in the genome by PCR with primers 1 and 2, and primer 1 and 3, respectively. The information should be useful for genomic research using the GFP line (C57BL/6‐Tg(CAG‐EGFP)C14‐Y01‐FM131Osb).Grant Funding Source: Supported by a grant from the Ministry of Health, Labor and Welfare of Japan.
Role of epigenetics and STAT5 in breast cancer resistance protein (BCRP/ABCG2) expression in the lactating mammary gland (1141.3)
Authors: Wu Alex , Dalvi Pooja , Yang Mingdong , Turinsky Andrei , Wang Kelvin , Butcher Darci , Egan Sean , Weksberg Rosanna , Brudno Michael , Harper Patricia , Ito Shinya 
Published: June 2021

The multidrug transporter breast cancer resistance protein (ABCG2) is upregulated in the mammary gland during lactation. We have shown that prolactin induces ABCG2 in human breast cancer cells via the recruitment of Signal Transducer and Activator of Transcription‐5 (STAT5) to the human ABCG2 gene. It is unclear if a similar mechanism regulates ABCG2 in vivo. Here we investigated epigenetic and transcriptional mechanisms that may control Abcg2 expression in the lactating mouse mammary gland. Expression profiling of three different Abcg2 mRNA isoforms (E1a, E1b, and E1c) revealed that the E1b isoform is predominately expressed and induced in the lactating mammary gland. Despite this significant induction during lactation, the E1b promoter region in the virgin gland is already hypomethylated and enriched with the open chromatin histone mark H3K4me2. Next we used a forced‐weaning model to stop lactation and to rapidly turn off Stat5 activity in the mammary gland. Within 48h after forced weaning, there was a significant reduction in Abcg2 mRNA expression with a corresponding reduction in Stat5 occupancy at the mouse Abcg2 gene. Taken together, our results suggest that the Abcg2 gene is already poised for expression in the virgin mammary gland and that the binding of Stat5 plays an important role in the regulation of Abcg2 during lactation.Grant Funding Source: Supported by CIHR.