bluuebunny/crossref_metadata_2025_split huggingface dataset:
Altered wall mechanics of conduit arteries of obese Zucker rats with progression of metabolic syndrome (867.8)
Authors: Chantler Paul , Fournier Sara , DeVallance Evan , Butcher Joshua , Frisbee Jefferson 
Published: June 2021

The metabolic syndrome (MetSyn) in obese Zucker rats (OZR) comes with a wide array of distinct vasculopathies including impaired endothelium‐dependent dilation and more modest alterations to VSM‐dependent responses (constrictor or dilator). While OZR do not develop atherosclerotic plaques, the presence of these alterations to wall mechanics in conduit arteries would have significant implications for pulse wave propagation, thrombo‐embolytic events, and responses to cardiovascular events such as stroke. To address this, we studied the mechanics of ex vivo carotid arteries (CA) from 17 week old OZR, where vascular tone was abolished. OZR exhibited obesity, severe insulin resistance, moderate hypertension and dyslipidemia. In response to elevated intraluminal pressure, CA from OZR exhibited a smaller expansion than CA from LZR. However, wall thickness and cross‐sectional area was reduced in CA from OZR vs. LZR. At low intraluminal pressures, incremental distensibility of CA from OZR was reduced vs. LZR. The circumferential stress vs. strain relation for CA from OZR was left‐shifted vs. LZR, with an increased β (slope) coefficient (p<0.01). These results suggest that CA stiffness in OZR is increased over that in LZR and that this loss of arterial distensibility could contribute to poor cardiovascular outcomes in MetSyn.Grant Funding Source: Supported by National Institutes of Health and American Heart Association
Respiratory virus co‐infection enhances Pseudomonas aeruginosa biofilm growth on airway epithelial cells (869.1)
Authors: Bomberger Jennifer , Lashua Lauren , Fischer Douglas , Hendricks Matthew 
Published: June 2021

Clinical observations link respiratory virus infection and Pseudomonas aeruginosa colonization in chronic lung disease, including cystic fibrosis and chronic obstructive pulmonary disease. The development of P. aeruginosa into highly antibiotic resistant biofilm communities promotes airway colonization and accounts for disease progression in chronic lung disease patients. We hypothesized that respiratory viral co‐infection promotes P. aeruginosa biofilm growth and colonization. In the presence of respiratory syncytial virus (RSV) co‐infection, we observed a significant increase in P. aeruginosa biofilm formation on airway epithelial cells (AECs). RSV infection induces a potent antiviral innate immune response in AECs through interferon (IFN)‐λ signaling. IFN‐λ signaling is capable of recapitulating the RSV‐induced bacterial biofilm formation. We have isolated the biofilm stimulatory activity to purified exosomes in conditioned media obtained from AECs infected with RSV. Iron is essential to P. aeruginosa growth and biofilm maturation, and chelation of iron inhibits biofilm growth on human AECs. We observed increased levels of iron in conditioned media from RSV‐infected AECs and chelation of iron in the conditioned media blocked biofilm stimulation. RSV infection did not alter iron transporter abundance in the plasma membrane, but dramatically enhanced the epithelial transcytosis and apical secretion of exosome‐associated, iron‐bound transferrin. This represents the first study that links viral co‐infection, and the resulting iron transport defect, to the development of biofilms and chronic bacterial infections.Grant Funding Source: Supported by R00HL098342 and P30DK072506 (JMB)
Azithromycin induces sestrin2 expression through Nrf2 signaling pathway in lung epithelial cells stimulated with cigarette smoke extract (869.11)
Authors: Yang Yu , Cuevas Santiago , Armando Ines , Jose Pedro 
Published: June 2021

Azithromycin has been reported to reduce exacerbation of chronic obstructive pulmonary disease (COPD) based on its antioxidant and anti‐inflammatory effects. The aim of this study was to identify the underlying molecular mechanisms. We found that decreased intracellular Nrf2 protein level (‐55±6%) and downstream target NQO1 (‐45±4%), increased reactive oxygen species (ROS) production (1.6‐fold) and interleukin 8 (IL‐8) secretion (2.1‐fold) in A549 cells exposed to cigarette smoke extract (CSE) (200ug/ml, 24h). Pretreatment with azithromycin (5µg/ml) suppressed ROS production (‐29±4%) and IL‐8 (‐45±6%) induced by CSE. Furthermore, azithromycin promoted Nrf2 nuclear translocation. Sestrin2, an antioxidant enzyme, was increased after azithromycin treatment in a time and concentration dependent manner. Additionally, azithromycin reduced hyper‐oxidized peroxiredoxins, the downstream target of sestrin2. Knockdown of Nrf2 resulted in suppression of azithromycin‐induced sestrin2 expression (‐35±3%). Silencing sestrin2 abolished azithromycin‐induced decrease in peroxiredoxins hyper‐oxidation and partially attenuated the inhibitory effect of azithromycin on ROS production and IL‐8 expression (by 26% and 41%, respectively). Our results suggest that one of the antioxidant and anti‐inflammatory effects of azithromycin in COPD may be, in part, mediated by induction of sestrin2 via Nrf2.Grant Funding Source: HL068686
Pseudomonas aeruginosa quorum‐sensing homoserine lactone inhibits O2 consumption and stimulates H+ secretion by airway epithelia (869.2)
Authors: Machen Terry , Schwarzer Christian , Fischer Horst 
Published: June 2021

P. aeruginosa biofilms accumulate in the airways of cystic fibrosis patients and produce the quorum‐sensing molecule N‐(3‐oxododecanoyl)‐homoserine lactone (C12) that depolarizes mitochondria. We tested whether C12 and P. aeruginosa biofilms change O2 consumption and H+ secretion into the extracellular fluid of JME (CF nasal epithelia, ΔF508CFTR) and CFTR‐corrected JME cells studied in Seahorse X24‐well dishes. C12 caused dose‐dependent (min = 1 µM, max = 50 µM) inhibition of O2 consumption (to 0.6x control) and increases in H+ secretion (to 1.3x control), similar to effects of mitochondrial poisons antimycin + rotenone. As measured by pH‐stat, C12 increased H+ secretion into the apical solution of human tracheal epithelial (HTE) cells in primary culture by 0.3 µeq.cm‐2.hr‐1, similar to rates measured using Seahorse. H+ secretion by HTE cells was blocked by Zn2+. PAO1wt biofilms inhibited O2 consumption and increased H+ secretion by JME cells, while PAO1lasI biofilm and planktonic PAO1wt did not. JME and CFTR‐corrected JME cells behaved similarly during all treatments. These data indicated: (i) P. aeruginosa biofilms, most likely operating through C12, inhibit O2 consumption and stimulate H+ secretion by airway epithelia. (ii) H+ secretion occurs through a Zn2+‐sensitive H+ channel in the apical membrane. (iii) Although there is no direct role for CFTR in these processes, a downward spiral in CF is predicted: increased acidity in CF ASL (no HCO3 secretion) → reduced antimicrobial factors → P. aeruginosa accumulation in biofilms → inhibit mitochondrial metabolism and increase anaerobic glycolysis in epithelia → increased epithelial secretion of H+ → increased acidity in ASL → reduced antimicrobial factors → increased P. aeruginosa accumulation.Grant Funding Source: NIH, CFRI
Beta adrenergic pathway independent relaxation of human airway smooth muscle (870.9)
Authors: Komalavilas Padmini , Brophy Colleen , Cheung‐Flynn Joyce 
Published: June 2021

Severe acute asthma, defined as asthma that is refractory to current anti‐inflammatory agents and bronchodilators, accounts for an estimated two‐million emergency department visits annually. β2‐adrenergic receptor (β2AR) agonists (β‐agonists) are widely used for the treatment of bronchospasm associated with acute asthma attacks, however, some patients develop refractory responses to long term usage of β –agonists. It also causes adverse effects in patients with a genetic polymorphism (Arg/Arg genotype, about a sixth of the US population) in the adrenergic receptor creating a need for additional therapeutics for managing asthma. We have shown earlier that β‐agonist induced airway smooth muscle (ASM) relaxation is associated with increases in the phosphorylation of HSP20. In this study we evaluate the effect of a transducible phosphopeptide mimetic of HSP20 protein (P20 peptide) on the relaxation of human ASM. Freshly isolated human ASM was pretreated with either a β‐agonist, isoproterenol (ISO), or the P‐20 peptide followed by a bronchoconstrictor, carbachol and force was measured in a tissue bath system. ISO blocked carbachol induced contraction in human ASM by activating the β2AR pathway. P‐20 peptide also blocked carbachol induced contraction of ASM, but in a β2AR independent manner. P20 peptide also relaxed human ASM precontracted with carbachol. These results suggest that the P20 peptide targets molecular events downstream of the β‐agonists‐cAMP pathway and that P20 peptide may be developed as a therapeutic to alleviate bronchospasm for patients who are refractory to β‐agonist, thus reducing the morbidity, mortality, and costs associated with managing asthma.Grant Funding Source: Supported by NIH RO1 70715
The orexin receptor 1 in the locus coeruleus modulates the hypercapnic ventilatory response in unanesthetized rats (872.12)
Authors: Vicente Mariane , Dias Mirela , Bicego Kenia , Gargaglioni Luciane 
Published: June 2021

Orexin modulates CO2‐drive to breath and there is an extensive population of orexin receptor 1 (OX1R) in the Locus coeruleus (LC). We tested the hypothesis that OX1R located in the LC is involved in chemoreception. To this end, we injected SB‐334867 (OX1R antagonist, 5 mM) into the LC of male Wistar rats. Pulmonary ventilation (VE), body temperature (Tb, dataloggers), mean arterial pressure (MAP) and heart rate (HR) were measured in air followed by hypercapnia (7% CO2) in unanesthetized rats. Hypercapnia caused an increase in VE, which resulted from increases in respiratory frequency (fR) and tidal volume (VT), but did not affect MAP, fH or Tb in all groups. SB‐334867 caused a significant attenuation (70%), of the hyperpnea induced by hypercapnia (n=9) compared with its vehicle (n=6; P< 0.05). This effect was due to both decreased VT and f. Basal ventilation, MAP, HR or Tb, were not affected by OX1R antagonism. These results suggest that projections of orexin‐containing neurons to the LC contribute via orexin R1 to the hypercapnic chemoreflex control in unanesthetized rats.Grant Funding Source: FAPESP and CNPq
Conditional knockdown of Kir4.1 in astrocytes blunts the hypercapnic respiratory response in awake mice (872.7)
Authors: Hawkins Virginia , Kuo Fushan , Bellemare Laura , Perez Diana , Dubreuil Todd , Mulkey Daniel 
Published: June 2021

Central chemoreception is the mechanisms by which the brain regulates breathing in response to changes in tissue CO2/H+. The retrotrapezoid nucleus (RTN) has been identified as a key locus for central respiratory control. Neurons in this region sense CO2/H+ in part by inhibition of TASK‐2 channels. RTN astrocytes are also chemosensitive and CO2‐evoked release of the gliotransmitter ATP most likely occurs via hemichannels. However, RTN astrocytes also respond to bath acidification with ~8 mV depolarization, which is mediated by inhibition of a Kir4.1‐like conductance. The contribution of this pH sensitive current in RTN astrocytes to central respiratory drive is yet to be determined. Here we generate a tamoxifen inducible, astrocyte specific Kir4.1 knockout (ciKir4.1KO) by crossing GFAP‐CreERT2 and a Kir4.1 floxed mouse lines. Whole‐body plethysmography experiments performed on 6 week old mice show that ciKir4.1KO animals breathe normally control conditions but exhibit a reduced tidal volume response to CO2 compared to tamoxifen treated GFAP‐CreERT2 Kir4.1 wild type (i.e., control) mice. These results suggest that Kir4.1 channels in astrocytes contribute to the CO2 ventilatory response in awake mice.Grant Funding Source: NIH HL104101 (DKM)
Acute leptin evokes physiological responses in rat carotid body type I cells (873.4)
Authors: Pye Richard , Ricker Ellen , Jurcsisn Jennifer , Barr Barbara , Wyatt Christopher 
Published: June 2021

Leptin is a central stimulant of respiration and also contributes to obesity related sympathoactivation. Recently leptin receptors have been identified on type I cells from the carotid body. Our most recent data indicate that activation of these receptors with leptin initiates calcium signaling events and increases outward macroscopic currents in isolated type I cells.The acute (10 min) application of leptin (200 ng.ml‐1) evoked calcium signaling responses in isolated type I cells. Cells significantly increased their Fura 2 F340/F380 ratio by 0.09 ± 0.015 ratio units (n =24, P < 0.001). Leptin also increased the peak membrane currents in a subset (65%) of type I cells. At +10mV leptin (200ng.ml‐1) increased peak macroscopic currents from 123 ± 19 pA.pF‐1 to 198 ± 28 pA.pF‐1 (n = 6, P < 0.02). The remaining 35% of type I cells were unresponsive to this concentration of leptin. Interestingly, leptin does not alter the rate of oxidative phosphorylation in isolated type I cells as measured by reduction of C12‐resazurin to C12‐resorufin.These data suggest that changes in leptin signaling may potentially influence carotid body function at the level of the type I cell. Given the involvement of the carotid bodies in the control of breathing and sympathetic tone, this finding may be especially pertinent to obesity related pathologies such as obesity hypoventilation syndrome and essential hypertension.Grant Funding Source: Supported by NIH‐1RO1HL091836 & NIH‐ 1S10RR025075‐01
Sepsis progression and multiple organ dysfunction in rats: carotid body involvement (873.5)
Authors: Fernández Ricardo , Cortes Paula , Nardocci Gino , Navarro Cristina , Rodriguez Jorge , Reyes Edison 
Published: June 2021

Sepsis syndromes involve pathological processes often leading to multiple organ dysfunction (MOD) and death. Sepsis progresses to MOD due uncontrolled release of inflammatory mediators. Lately, increasing evidence supports the idea that the carotid body both regulates the immune status and plays a protective role during sepsis syndromes. In anaesthetized (pentobarbitone, 60 mg/kg IP) male Sprague‐Dawley rats (BW 100±20 g) we measured plasma levels of cytokines, chemokines and MOD‐markers, 90‐min after IP administration of either saline or 15 mg/kg LPS in control (SHAM surgery; intact carotid/sinus nerves) and in bilateral carotid chemo/baro‐denervated rats (BCN). Respiratory frequency (fR) and heart rate (fH) were augmented in SHAM‐LPS group, but systolic blood pressure (PS) dropped. BCN decreases the survival time of rats and blunts the fR response to LPS but enhancing both, the fH increase and the PS fall. SHAM‐LPS and BCN‐LPS rats shown increased plasma levels of IL‐1β, IL‐10, and TNF‐α; however, the increase in both ILs was lower in BCN‐LPS, which also had augmented IL‐2 levels. Unchanged cortisol plus increased levels of epinephrine can be related to increased plasma levels of TNF‐α. Finally, BCN‐LPS induced an early onset of MOD identified by increased plasma levels of creatine kinase, amylase, creatinine, neutrophil gelatinase‐associated lipocaline, total bilirrubin and alanine aminotransferase. We propose that carotid body would modify the inflammatory response during sepsis syndromes through a communication network involving neural, humoral, and cytokine components, and also would play a protective role in the sepsis progression to MOD.Grant Funding Source: Supported by: FONDECYT 1120976 and UNAB DI‐354‐13/R (to RF) and UDD CI 23400098 (to PR)
Role of the carotid chemoreceptors in insulin‐mediated sympathoexcitation in humans (873.7)
Authors: Limberg Jacqueline , Mozer Michael , Joyner Michael , Curry Timothy 
Published: June 2021

Objective: Given recent evidence from rodents supporting a novel role for the carotid bodies in insulin‐mediated sympathoexcitation, we sought to determine whether carotid chemoreceptor desensitization would reduce muscle sympathetic nerve activity (MSNA) during hyperinsulinemia in humans. Methods: Young, healthy subjects (n=4, 30±2 yrs) breathed hyperoxic gas (End‐tidal O2 = 100%, PaO2 505±13 mmHg) for 15 min at baseline and during steady‐state hyperinsulinemia (5±1 vs 53±1 µU/mL). Hyperinsulinemia was achieved using a 90‐min hyperinsulinemic (1 mU/kg FFM/min), euglycemic (108±4 mg/dL) clamp. CO2 was maintained at resting levels (PaCO2 41±1 mmHg). Changes in heart rate, blood pressure, minute ventilation, and MSNA (microneurography of the peroneal nerve) were assessed. Results: Hyperinsulinemia increased MSNA [burst frequency (p<0.01), burst incidence (p=0.02), total activity (p=0.02)]. Hyperoxia decreased heart rate (p=0.01) and minute ventilation (p=0.11), and increased mean blood pressure (p=0.04). Consistent with our hypothesis, the effect of hyperoxia on MSNA (Δ) was different between baseline and hyperinsulinemia (burst frequency, p=0.03; burst incidence, p=0.10). Conclusion: These data are the first to suggest the carotid chemoreceptors may contribute to insulin‐mediated sympathoexcitation in humans.Grant Funding Source: Supported by: NIH R01 DK090541 (MJJ), NIH T32 DK07352 (JKL)
Overexpression of GRK5 prevents angiotensin II blockade of peak potassium currents and normalizes Kv4.3 expression in neurons (874.12)
Authors: Becker Bryan , Haack Karla , Zucker Irving 
Published: June 2021

The Angiotensin II (Ang II)‐ Ang II type 1 Receptor (AT1R) signaling axis has been shown to decrease peak potassium (K+) currents (Ito) and Kv4.3 (a voltage gated K+ channel subunit) expression. G protein coupled receptor kinase 5 (GRK5) phosphorylates AT1R and desensitizes it. We hypothesized that GRK5 overexpression can blunt the Ang II‐mediated decrease in Ito and normalize Kv4.3 expression in CATH.a neurons. Neurons were transfected with either mock or pcDNA3‐GRK5 plasmid and stimulated with either vehicle or 100 nM Ang II for 4 hours. Neurons treated with Ang II exhibited decreased Ito relative to control (95.8 ± 16.6 vs 149.4 ± 18.9 pA/pF; p<0.05). This effect was attenuated by GRK5 overexpression (179.0 ± 34.5 pA/pF). Time to peak current was significantly increased in AngII neurons relative to control (45.5 ± 14.5 vs 21.3 ± 5.1 ms; p<0.05). GRK5 overexpression normalized this response (21.4 ± 5.6 ms). Western blot analyses indicated that GRK5 overexpression significantly increased basal Kv4.3 levels compared to sham (1.5 ± 0.3 vs 1.0 ± 0.1) but did not prevent the Ang II‐mediated decrease in Kv4.3 (0.5 ± 0.2 vs 0.7 ± 0.2). siRNA knockdown of GRK5 decreased basal Kv4.3 levels compared to sham (0.3 ± 0.1 vs 1.0 ± 0.1) and Ang II did not decrease Kv4.3 expression further. These data suggest that GRK5 overexpression blunts the Ang II‐mediated decrease in Ito. GRK5 may contribute to the regulation of Kv4.3.Grant Funding Source: Supported by NIH grant P01‐HL62222
Early surge in oxidative stress in the brain subfornical organ during angiotensin‐II‐induced hypertension (874.7)
Authors: Dong Frederick , Young Colin , Davisson Robin 
Published: June 2021

Angiotensin‐II (Ang‐II)‐dependent hypertension is characterized by oxidative stress, endoplasmic reticulum (ER) stress, and transcription factor activation in the subfornical organ (SFO). However, the relative temporal pattern of these responses remains unclear. As a first step, we tested the hypothesis that reactive oxygen species (ROS) levels increase early in the SFO during Ang‐II‐induced hypertension. Male C57B1/6 mice were implanted with osmotic minipumps for low dose infusion of Ang‐II (600 ng/kg/min) and were sacrificed at day 0, 3, 5, 7, and 14 (n=3‐4/timepoint). Brains were collected, and SFO cryosections were obtained and stained with dihydroethidium to quantify ROS production. No changes in SFO ROS levels were found at day 3 of Ang‐II, relative to day 0 (0.7±0.1 fold day 0, p>0.05). However, a surge in ROS production within the SFO occurred at day 5 (1.7±0.2 fold day 0, p<0.05), prior to an increase in arterial pressure, and this response was maintained for up to 14 days (1.5±0.1 fold day 0, p<0.05). Interestingly, we have also found a surge in nuclear factor‐ĸ‐B activation at day 5 (3.7±1.4 fold day 0; p<0.05), as well as upregulation of ER stress biomarkers at day 7. These findings demonstrate for the first time an early pre‐hypertensive increase in oxidative stress within the SFO that coincides with transcriptional activation and the occurrence of ER stress.Grant Funding Source: Supported by HL63887, HL96571, HL84207, AHA13POST14410020, K99HL166776
Silencing of Nox2 and Nox4 in the subfornical organ prevents renal but not aortic T cell infiltration during angiotensin II‐induced hypertension (874.9)
Authors: Lob Heinrich , Song Jiunn , Butler Scott , Peterson Jeffrey , Mark Allyn , Davisson Robin 
Published: June 2021

Reactive oxygen species (ROS) in the SFO are crucial for Ang II HTN and have been linked to aortic T cell activation. Signals from the SFO regulate renal sympathetic nerve activity (RSNA). Increased RSNA contributes to renal T cell activation. Here we compared the effects of silencing the two NADPH oxidase (Nox) isoforms (Nox2, Nox4) found in the SFO on aortic and renal T cell activation during Ang II HTN. We targeted the SFO of C57Bl/6 mice with adenoviruses encoding siRNAs directed selectively against Nox2 and Nox4 (AdsiNox2 + AdsiNox4). One week later osmotic minipumps were implanted to infuse Ang II (600 ng/kg/min) for 14 days. Silencing of both Nox2 and Nox4 significantly reduced SFO ROS and blunted Ang II‐HTN. Flow Cytometry revealed that despite normal arterial pressure, silencing of Nox2 and Nox4 in the SFO did not prevent aortic T cell infiltration in response to Ang II (AdLacZ Veh: 0.2 ± 0.06 x 104, Ang II: 5.6 ± 2.0 x 104; AdsiNox2+AdsiNox4 Veh: 0.09 ± 0.02 x 104, Ang II: 9.1 ± 3.8 x 104 cells/aorta; n=5‐8, p<0.05 vs AdLacZ). In contrast, renal T cell infiltration was blunted in these animals (AdLacZ Veh: 0.2 ± 0.05 x 104, Ang II: 2.1 ± 0.4 x 104; AdsiNox2+AdsiNox4 Veh: 0.4 ± 0.1 x 104, Ang II: 0.4 ± 0.9 x 104; n=5, p<0.05). These findings demonstrate that Nox‐derived ROS in the SFO are important for renal T cell infiltration and kidney inflammation, and suggest that this may be important for the development of Ang II HTN.Grant Funding Source: 12SDG9160019, HL63887, HL96571, HL84207
Neural reflex control of immunity: the splanchnic anti‐inflammatory pathway (875.1)
Authors: Martelli Davide , Yao Song , McKinley Michael , McAllen Robin 
Published: June 2021

Exaggerated or insufficient inflammatory responses can both be life threatening, and the nervous system helps maintain inflammation within appropriate limits. It is believed that the parasympathetic vagus nerve acts via the splenic sympathetic nerve to down‐regulate the cytokine response to immune challenge. Here we report that the systemic inflammatory response in rats, measured by plasma levels of tumour necrosis factor‐α 90 minutes after intravenous lipopolysaccharide (LPS, 60μg/kg), was unaffected by vagotomy but was enhanced five‐fold if the splanchnic sympathetic nerves were cut. Plasma corticosterone levels were unaffected, so did not contribute. Electrophysiological recordings demonstrated that efferent neural activity in the splanchnic nerve and its splenic branch was increased at least four‐fold after LPS. Furthermore, we show that, under these conditions, the increase in the efferent neural activity in the splenic sympathetic nerves is entirely driven by the splanchnic nerves, not the vagi. Thus, immune challenge triggers a powerful inhibitory reflex that suppresses the inflammatory response. Its efferent pathway is in the splanchnic sympathetic nerves, not the vagi as previously thought.Grant Funding Source: Supported by NHMRC project grant 1051102