bluuebunny/crossref_metadata_2025_split huggingface dataset:
Brain ACE2 overexpression stimulates food intake and promotes glucose intolerance in mice (1126.15)
Authors: Xia Huijing , Chhabra Kavaljit , Littlejohn Nicole , Pearson Nicole , Grobe Justin , Lazartigues Eric 
Published: June 2021

The brain Renin‐Angiotensin System (RAS) plays an important role in the regulation of metabolic function. While ACE2 has been reported to modulate brain RAS activity, its role in the central regulation of metabolism is unknown. To determine the role of central ACE2 in metabolism, Body weight and intake behaviors, assessed using metabolic cages, were measured in 24 wk old non‐transgenic (NT, n=8) and transgenic mice overexpressing ACE2 in the brain (SA, n=8). Fasting blood glucose was measured after a 14 h overnight fasting. Glucose tolerance test was performed by measuring blood glucose at 15, 30, 60 and 120 min after IP injection of glucose (2 g/kg). Plasma insulin level was measured by ELISA. Interestingly, body weight was significantly higher in SA than NT mice (39±1.5 vs. 31±0.8 g, P<0.05). In addition, SA mice exhibited increased daily food intake (0.12±0.01 vs. 0.09±0.01 g/g body weight), water intake (0.14±0.01 vs. 0.08±0.01 ml/g body weight), fasting blood glucose (147.8±13 vs.106.5±7 mg/dl), impaired glucose tolerance (AUC: 51.6±2 vs.41.5±1.7) and increased plasma insulin level (5.5±1.2 vs.1.7±0.3 ng/ml), compared to NT mice (P<0.05). These data suggest that ACE2 is involved in the central regulation of energy and glucose homeostasis. Brain ACE2 over‐expression leads to increased body weight, fasting glycemia and glucose intolerance, possibly through stimulating energy intake and insulin resistance.Grant Funding Source: Supported by NIH (NIGMS)
Synaptic and neurochemical characteristics of the nucleus tractus solitarius pars centralis neurons (1129.7)
Authors: Babic Tanja , Browning Kirsteen , Travagli R. Alberto 
Published: June 2021

The nucleus tractus solitarius (NTS) receives gastrointestinal (GI), cardiovascular and respiratory visceral sensory information via A or C‐fibers. We have shown recently that, contrary to cardiovascular NTSmedialis neurons, the majority of esophageal NTScentralis (cNTS) neurons respond to vanilloid agonists while only a small subset responds to both vanilloid and purinerigic agonists.The aim of this study was to investigate further the neurochemical and synaptic characteristics of cNTS neurons using whole cell patch clamp and single cell RT‐PCR.Excitatory postsynaptic currents (EPSCs) were evoked in cNTS by tractus solitarius stimulation. Perfusion of the slices with αβ‐methylene ATP (αMeATP) increased the amplitude of the evoked EPSC in 9 of 23 neurons tested. Variance‐mean (V‐M) analysis was performed to determine synaptic characteristics of αMeATP‐responsive and non‐responsive neurons. αMeATP ‐responsive neurons had 40±16 release sites, quantal size was 21±9pA and 78±5% probability of release during perfusion with 2.4 mM [Ca2+]e. Conversely, non‐responsive neurons had 18±6 release sites, quantal size was 23±3pA and 75±4% probability of release at 2.4 mM [Ca2+]e. Single‐cell RT‐PCR revealed that 8/13 responsive neurons expressed mGluR8 mRNA, whereas only 3 expressed glutamic acid dehydroxylase (GAD). A significantly lower proportion of non‐responsive neurons expressed mGluR8 (2/30), whereas a greater proportion expressed GAD (12/30).These data demonstrate that cNTS comprises distinct sub‐populations of neurons that can be distinguished based on their responses to purinergic agonists and have distinct neurochemical and synaptic characteristics, suggesting that integration of sensory inputs from the esophagus relies on a discrete organization of synapses between vagal afferent fibers and cNTS neurons.Grant Funding Source: DK55530
The hypoxia‐sensitivity of RVLM sympathetic premotor neurons is mediated by glial ATP release (1130.1)
Authors: Bou Farah Lama , McMullan Simon 
Published: June 2021

Sympathoexcitatory neurons in the rostral ventrolateral medulla (RVLM) are excited by hypoxia, but the molecular mechanisms of oxygen sensing are unknown. Here we consider two mediators of hypoxia sensing: expression of the oxygen sensing molecule heme oxygenase 2 (HO‐2) and glia ATP release.We examined the distribution of HO‐2 immunoreactivity in bulbospinal and catecholaminergic brainstem neurons in adult (n = 3) and neonatal (n = 2) rats. Whole cell responses of bulbospinal neurons to acute hypoxia (sodium cyanide, NaCN, 5, 10 or 20 mM) were recorded in acute brainstem slices before and after blockade of HO‐2 (SnPP‐IX, 10 μM) or ATP receptors (PPADS, 30 μM) and in a specific glial toxin (Fluoroacetate, 5 mM).NaCN caused dose dependent inward currents that were greater in bulbospinal (n = 27) compared to non bulbospinal neurons (1029 ± 316 vs. 169 ± 43 pA at 20 mM NaCN, P < 0.01, n = 12). Responses were unaffected by synaptic (TTX 10 μM, I = ‐13 ± 12%, P > 0.05, n = 5) or HO‐2 blockade (ΔI = 16 ± 26%, P > 0.05, n = 5). HO‐2 immunoreactivity was absent in catecholaminergic and bulbospinal neurons and in 12 hypoxia sensitive biocytin filled bulbospinal neurons. Responses to NaCN were reduced by ATP receptor blockade (ΔI = ‐51± 13%, P < 0.01, n = 6) and abolished by gliocide (20.6 ± 7.7 pA at 20 mM NaCN, n = 12, P < 0.001).These data suggest a crucial role for RVLM glia, not HO‐2, in driving sympathetic responses to hypoxia.
Modulation of arousal state and temperature is unaltered but activity is increased in tryptophan hydroxylase 2 knockout mice (1130.5)
Authors: Solarewicz Julia , Richardson Chelsea , Angoa‐Pérez Mariana , Kuhn Donald , Mateika Jason 
Published: June 2021

Purpose: There is widespread belief that serotonin in the central nervous system (CNS) has a role in modulating various physiological functions including temperature, activity, and arousal state. Thus, we hypothesized that the absence of serotonin would be accompanied by hypersomnia, a reduction in activity and decreased temperature modulation.Methods: Telemetry transmitters were surgically implanted in 12 mice with a null mutation for tryptophan hydroxylase 2 (Tph2‐/‐) and 12 wild type mice (Tph2+/+). Thereafter, electroencephalography, core body temperature and activity were recorded for 24 hours.Results: Temperature during wake and sleep was modulated in a similar manner in both groups over the 24 hr period. Likewise, the change in temperature between the sleep and wake state was similar between the Tph2‐/‐ and Tph2+/+ mice (0.34 ± 0.09 vs. 0.37 ± 0.16 °C). The percentage of time spent in a given state of arousal was similar between the Tph2‐/‐ and Tph2+/+ mice (e.g. 40.6 ± 9.6 vs. 41.3 ± 7.2, % time sleeping). However, Tph2‐/‐ mice were more active (3.3 ± 1.5 vs. 1.7 ± 0.9 counts/s, p = 0.02) for a greater percentage of wakefulness (17.8 ± 6.8 vs. 14.2 ± 5.0 %, p = 0.05).Conclusion: The modulation of temperature within or across arousal states, as well as, the duration of sleep and wake is not impacted by the absence of serotonin in the CNS. In contrast, the level of activity during wakefulness is increased in Tph2‐/‐ mice.Grant Funding Source: Supported by: VA Award ‐ 1IO1 RX000458 (DMK) & 1I21RX001412 (JHM)
High salt diet increases glomerular ROS formation through an ET‐1/ETA dependent mechanism (1134.9)
Authors: Heimlich J. Brett , Speed Joshua , O'Connor Paul , Pollock David 
Published: June 2021

Endothelin‐1 (ET‐1) stimulates the production of reactive oxygen species (ROS) in pulmonary artery smooth muscle cells and also activates NADPH oxidase in isolated aortic rings. The connection between ROS production provides mechanistic insight into possible deleterious effects of ET‐1 dysregulation during pathological processes such as hypoxia. ET‐1 production is increased by a high salt diet (HSD), so we sought to test the effects of HSD on the capacity of glomeruli to produce ROS. C57BL6/J mice were placed on a normal or HSD and then treated with or without selective ETA antagonist ABT‐627 for one week (5 mg/kg/d p.o.). Untreated animals on a HSD had significantly increased levels of glomerular ROS production when stimulated by phorbol (PMA) mediated PKC activation compared to glomeruli from normal salt controls (77.5±7.8 v. 23.7±7.3 thousand ALU/mg protein, p<0.01, n=5‐6). However, HSD animals treated with ABT‐627 had a blunted increase in glomerular ROS production (44.3±11.5 thousand ALU/mg protein, n=6). To further test the etiology of ROS production, glomeruli were incubated with 100 µM apocynin, a NADPH oxidase inhibitor, which completely prevented PMA stimulation of ROS to sub‐control levels in normal and HSD treated animals (10.5±2.75 and 13.02±4.3 thousand ALU/mg protein, n=5‐6). These data provide evidence for ET‐1/ETA mediated glomerular injury via ROS production during increased dietary salt intake.Grant Funding Source: Supported by the National Institutes of Health
Chronic infusion of angiotensin II changed renal hemodynamic and function (1136.11)
Authors: Casare Fernando , Oliveira‐Souza Maria 
Published: June 2021

This study investigated the effect of chronic treatment with angiotensin II (Ang II) on renal injury.Methods: 35 days old male Wistar rats were divided into groups (n = 9/group): Sham, Ang II (s.c. infusion 200 ng/kg/min) for 42 days via mini‐osmotic pump),Losartan‐AT1 receptor antagonist (s.c. injection‐ 10 mg/kg/day) for 14 days and Ang II (42 days)/Losartan (14 days). Systolic blood pressure (SBP) was evaluated by tail‐cuff method. Renal plasmatic flow (RPF) and glomerular filtration rate (GFR) were determined by para‐aminohippuric acid and inulin clearance, respectively. Renal tissue was histologically analyzed and the results are expressed as mean ± SE and p 蠄 0.05 was considered significant (*vs Sham).Results: Ang II/AT1 increased the SBP [(mmHg) Sham: 108 ± 2, Ang II: 193 ± 7*]; renal hemodynamic [(mL.min‐1.Kg‐1) RPF ‐ Sham: 23 ± 1, Ang II: 34 ± 2* and GFR ‐ Sham: 7 ± 0.3, Ang II: 13 ± 1*], filtration fraction (Sham: 32 ± 1, Ang II: 41 ± 2%*) and urinary flow rate [(µL.min‐1) Sham: 49 ± 4, Ang II: 71 ± 3*]. Ang II/AT1 decrease renal vascular resistance, increased interlobular artery thickness and its luminal diameter; induced glomerular injury, proteinuria and podocyturia.Conclusion: Ang II infusion for 42 days induced via AT1 receptor, severe changes on renal hemodynamic and morphology leading to outward hypertrophic remodeling and chronic kidney disease.
Overexpression of miR‐20b inhibits the expression of HIF‐1α and STAT‐3 in invasive ductal carcinoma of the breast (1138.2)
Authors: Zanetti Juliana , Darin Patrícia , Lucca Fernando , Ribeiro‐Silva Alfredo 
Published: June 2021

It is known that the hypoxia inducible factor‐1α (HIF‐1α) and the signal transducer and activator of transcription 3 (STAT‐3) are targets of miR‐20b. The role played by microRNAs (miRNAs) in breast cancer has been mainly studied using tumor cells. In this study, we investigated the expression of miR‐20b in formalin‐fixed paraffin embedded (FFPE) samples, as also as HIF‐1α and STAT‐3, in samples of invasive ductal carcinoma (IDC). The expression of miR‐20b and the proteins HIF‐1α and STAT‐3 was evaluated by real time PCR and immunohistochemistry, respectively. We found that the overexpression of miR‐20b (3‐fold; p<0.05) is accompanied by the downregulation of STAT‐3 (70%; p<0.001) in FFPE samples of IDC. We also observed that HIF‐1α expression in IDC and control samples was not statistically significant. Our results suggest that miR‐20b regulates the expression of HIF‐1α and its transcription factor STAT‐3 in IDC. These findings are relevant since HIF‐1α expression has been correlated with increased intratumoral angiogenesis, cancer progression and poor prognosis in breast cancer.Grant Funding Source: Supported by FAPESP 2012/05235‐3
The potent inhibition of human SULT1A1 by 17α‐ethinylestradiol (EE2) is due to interactions with ILE89 in loop 1 (1141.12)
Authors: Rohn‐Glowacki Katie Jo , Falany Charles 
Published: June 2021

Drug‐drug interactions (DDI) are a concern for the 17% of women in the United States taking birth control pills. Competition for metabolism with phase I and II drug metabolizing enzymes is one cause of these DDI. The object of this study was to determine the mechanism of SULT1A1 inhibition by EE2. SULT1A1 is the major drug/xenobiotic conjugating isoform found mainly in liver and the GI tract, but is also widely expressed at varying levels in other tissues including breast and brain. SULT1A1 conjugates a broad range of xenobiotics and endogenous compounds such as small phenols, estrogens, and acetaminophen. The Km of EE2 for SULT1A1 is 3.5‐fold lower than the Km of 17β‐estradiol (E2). In silico docking of EE2 to SULT1A1 crystal structures and homology models suggested that EE2 may inhibit SULT1A1. The inhibition constant range for E2, 2‐naphthol, and p‐nitrophenol was 9‐19nM, a physiological range for potent inhibition of SULT1A1. We were interested in the mechanism by which EE2 could inhibit SULT1A1 at low nanomolar concentrations while EE2 is not sulfated until assay concentrations are 30‐fold higher. Therefore, further analysis of the docking studies identified two amino acids that may contribute to EE2 inhibition, TYR169 and ILE89. Mutants of each residue were made, TYR169PHE (Y169F) and ILE89ALA (I89A), and tested for sulfation by and inhibition of EE2. Both mutants displayed the same Km for E2; however, the Km of EE2 for SULT1A1‐Y169F increased 3‐fold while the Km for SULT1A1‐I89A increased 10‐fold. The SULT1A1‐Y169F mutant retained the ability of EE2 to inhibit substrate sulfation with a slightly higher Ki although still in the nanomolar range, whereas SULT1A1‐I89A inhibition by EE2 was almost completely abolished at the concentrations tested. These data provide a better understanding of the SULT1A1 active site and indicate that the potent inhibition of SULT1A1 by low nanomolar EE2 concentrations may be a source of DDI in women using EE2 containing contraceptives.Grant Funding Source: Supported by NIH GM38953
Pharmacovigilance‐pharmacological investigations on sulfonylureas and glinides‐induced atrophy in skeletal muscle (1142.5)
Authors: Cetrone Michela , Mele Antonietta , Calzolaro Sara , Conte Diana , Tricarico Domenico 
Published: June 2021

The atrophy of the skeletal muscle apparatus is a comorbidity condition in the diabetes type II representing a negative prognostic factor. The effects of the anti‐diabetic drugs on the diabetes type II‐related atrophy have never been investigated. The “in vitro” effects of the sulfonylureas (tolbutamide, glibenclamide and glimepiride) and glinides (repaglinide and nateglinide), well known KATP channel blockers, were evaluated on the protein content/muscle weight, fibers viability, mitochondrial SDH activity and channel currents in oxidative soleus(SOL), glycolitic/oxidative flexor digitorum brevis(FDB) and glycolitic extensor digitorum longus(EDL) muscle fibers of mice using biochemical and cell‐counting Kit‐8 assay, imagine analysis and patch‐clamp techniques. FDA‐adverse effects reporting system evaluation of atrophy‐related signals associated with the use of these drugs in humans has been performed. In animal experiments, all drugs after 24 h of incubation time reduced the protein content and fibers viability blocking the KATP channel and enhancing the SDH activity. Repaglinide and glibenclamide were the most potent drugs. In an eight month period, muscle atrophy was found in 0.27% of the glibenclamide reports in humans and in 0.022% of the other not sulfonylureas/glinides drugs. Glibenclamide induces atrophy in animals and in humans. Glimepiride shows a less potential of inducing atrophy.Grant Funding Source: none
Cardiac hypertrophy and oxidative metabolism in novel congenic leptin receptor deficient BBDR.cg‐lepr.cp rats (1155.10)
Authors: Gomez Maria F. , Silvola Johanna , Berglund Lisa M. , Kiugel Max , Åkesson Lina , Knuuti Johani , Roivainen Anne , Lernmark Åke , Nuutila Pirjo , Saraste Antti 
Published: June 2021

Congenic BBDR.cg‐lepr.cp rats generated by introgression of the Koletsky leptin receptor mutation into the BioBreeding Diabetes Resistant (BBDR) rat develop obesity and diabetes mellitus, known risk factors for heart failure. Here we studied cardiac function and myocardial oxidative metabolism in these rats by non‐invasive imaging. Myocardial glucose utilization (18F‐fluorodeoxyglucose uptake) and oxygen consumption (washout constant for 11C‐acetate derived from monoexponential fitting) were measured by positron emission tomography (PET); left ventricle (LV) mass, systolic function and cardiac output by echocardiography. Compared with non‐diabetic littermates, diabetic rats were obese (body weight 463±36 vs. 706±65 g, p<0.01), hyperglycemic (6±1 vs. 22±10 mM, p<0.01), had elevated blood pressure (136±5 vs. 151±13 mmHg, p=0.02), comparable systolic function (fractional shortening 49 vs. 48%), but higher LV mass (0,6±0,1 vs. 0,9±0,1 g, p<0.01). Diabetic rats had lower fasting myocardial glucose uptake (p=0.04) and lower efficiency of myocardial forward work (LV work / oxygen consumption * myocardial mass; 69000±8000 vs. 54000±12000 mmHg L/min; p=0.03), despite having comparable resting myocardial oxygen consumption in fasting state. Results suggest that BBDR.cg‐lepr.cp rats should prove a useful new model to study the adverse effects of obesity and diabetes on cardiac metabolism.Grant Funding Source: Supported by: VR 2011‐3900; EFSD, SSMF, the SUMMIT consortium (IMI‐2008/115006).
Toll‐like receptor 2 activation increases contractile responses in rat corpus cavernosum (1158.6)
Authors: Stallmann‐Jorgensen Inger , Wenceslau Camilla , Ogbi Safia , Webb R. Clinton 
Published: June 2021

Erectile dysfunction (ED) affects about 30 million US men and is recognized as a sign of heightened cardiovascular disease (CVD) risk. Inflammation in the vasculature could be the link between ED and CVD. Activation of innate immune toll‐like receptors can trigger vascular inflammation. Toll‐like receptor 2 (TLR2) has been implicated in CVD, but whether TLR2 signaling contributes to penile vascular dysfunction is unknown. We hypothesized that a synthetic TLR2 ligand, Pam3CSK4, would increase contraction to phenylephrine (PE) in rat corpus cavernosum (CC). The CC of adult Sprague Dawley rats was isolated, cleaned, cut into muscle strips, and incubated with 100 ng/mL Pam3CSK4 (Pam3) or vehicle (CON) for 6 h and subsequently mounted on a myograph for isometric force measurements. Contraction to 80 mM KCl confirmed CC viability and force (mN) data were normalized to KCl contraction (%KCl). Western blotting was used for protein determination. Data analyses were performed using Two‐way ANOVA and unpaired t‐tests with α‐level set at 0.05. Pam3 compared to CON showed higher contractile responses to PE across the 10uM‐1mM concentration range (mean differences in force ranged from 51.15 to 67.18 %KCl; p<0.05, RM ANOVA, n=4‐5). Pam3 showed a higher maximal response to PE than CON (Pam3: 205.5±8.5 vs. CON: 138.4±16.8 % KCl; p<0.05, t‐test). The p‐IKBα:total IkBα ratio was greater in Pam3 vs. CON (Pam3: 2.5 fold‐change over CON; p<0.05, t‐test, n=4). In conclusion, a TLR2 ligand increases contractile responses to PE in CC, suggesting that this pattern recognition receptor plays a role in CC. TLR2 may be a link between ED and sterile inflammation.Grant Funding Source: Supported by NIH
Glucocorticoids reduce muscle atrophy‐related microRNAs via exosomal microRNA packaging (1163.4)
Authors: Hudson Matthew , Woodworth‐Hobbs Myra , Rahnert Jill , Zheng Bin , Price S. 
Published: June 2021

Several microRNAs, including miR‐23a and miR‐182, participate in skeletal muscle atrophy by regulating the level of key atrophy‐inducing proteins. We recently found that the intracellular levels of these microRNAs are reduced in C2C12 myotubes within 1‐2 hours of addition of the glucocorticoid dexamethasone (Dex). The purpose of this study was to investigate the mechanism underlying the rapid decrease in the intracellular levels of these microRNAs. We tested the hypothesis that miR‐23a and miR‐182 are incorporated into exosomes and exported from myotubes following glucocorticoid treatment. Administration of Dex (1µM) to C2C12 myotubes for 6 h in exosome‐free culture media resulted in decreased intracellular miR‐23a and miR‐182. Isolation and quantitation of exosomal miR‐23a and miR‐182 from media revealed an increase in both microRNAs. Interestingly, the total number of exosomes in the culture media of control and Dex‐treated cells was not different indicating Dex did not increase exosome export. Levels of miR‐23a and miR‐182 were decreased in gastrocnemius muscle of rats undergoing atrophy due to streptozotocin‐induced diabetes. MiR‐23a and miR‐182 in urinary exosomes from diabetic rats were also reduced, suggesting that their levels in urine reflect the levels in muscle during the persistent atrophic state. These findings identify a novel mechanism by which muscle can rapidly reduce the level of intracellular microRNAs, and demonstrate that exosomal microRNA packaging is a specific and highly regulated process.Grant Funding Source: Supported by NIH T32 DK007656 (MBH) and NIH DK95610, VA Merit X01BX001456 (SRP)
Blood pressure responses to skeletal muscle contraction relative to salt sensitivity in humans and rats (1165.11)
Authors: Matthews Evan , Stocker Sean , Brian Michael , Wenner Megan , Edwards David , Farquhar William 
Published: June 2021

Salt sensitivity of blood pressure (BP) is linked to increased mortality. Salt sensitive (SS) rats display exaggerated BP responses to muscle afferent stimulation, a finding not yet studied in humans. We hypothesized that SS adults would have greater BP responses to muscle contraction than salt resistant (SR) adults. To define salt sensitivity status, a median split of 24hr mean BP (MAP) responses (%∆) to dietary sodium (20 mmol/d x 7 d to 300 mmol/d x 7 d sodium) was used in 12 adults and resulted in 6 SS (6.4±1.5 %∆) and 6 SR (‐0.1±1.6 %∆ p<0.05). Static handgrip (HG; 2 min 40% maximal voluntary contraction) was performed during normal sodium intake. MAP responses to HG tended to be greater in SS than SR (30.2±5.1 vs. 16.7±4.0 %∆, p=0.06). Salt induced %∆MAP was correlated to HG %∆MAP (r=0.658 p<0.05). Parallel experiments in Dahl SS (DSS, n=4) &amp; Dahl SR (DSR, n=4) rats fed 0.1% NaCl confirms that stimulation of sciatic afferent nerves (500uA, 5Hz, 1ms pulse) produce greater increases in MAP (SS 26±4; SR 15±2 mmHg, p<0.05). Additionally we found greater renal sympathetic nerve activity (SS 175±12; SR 147±8 %, p<0.05). These preliminary data suggest greater BP responses to muscle contraction in SS humans &amp; rats due to greater sympathetic activity; this may be a factor in the poorer CV outcomes in SS adults.Grant Funding Source: Supported by NIH R01 HL104106, NIH R01HL113270 and AHA EIA, & ACSM Foundation Research Grant.