bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stimulation of Auricular Vagal Nerves Attenuates Pressor Cardiovascular Responses through Influence on Medullary nuclei
Authors: Guo Zhiling , Samaniego Tracy , Malik Shaista 
Published: April 2020

Stimulation of the auricular branch of the vagus nerve (ABVN) is used to manage cardiovascular disorders, including elevated blood pressure. However, precise mechanisms underlying its effects remain unclear. One previous study showed that ABVN stimulation with acupuncture at the center of the inferior concha (the “heart acupoint,” CO15) activates neurons in the nucleus tractus solitarii (NTS) through vagal inputs. Still, its actions on NTS processing and downstream influence on the nucleus regulating cardiovascular function have not been studied. Thus, the present study evaluated the effect of ABVN stimulation on pressor cardiovascular responses and the underlying neural mechanisms associated with medullary nuclei. We hypothesized that ABVN stimulation with acupuncture activates the NTS and ultimately inhibits rostral ventrolateral medulla (rVLM), a critical region controlling cardiovascular function, through opioid and GABA mechanisms. In Sprague‐Dawley rats, repeated pressor cardiovascular reflexes were induced by repetitive gastric distension (GD) under anesthesia. ABVN stimulation with manual acupuncture was performed at the CO15 acupoint with gentle rotation of the acupuncture needle at a frequency of □2 Hz for four min every 10 min during a 30 min period, 2 min in each side of the ear. During sham‐ABVN stimulation, the acupuncture needle was inserted into the same site without subsequent rotation of the needle. Unilateral microinjection of the chemical (50 nl) was conducted in the NTS and rVLM. We found that GD‐induced pressor cardiovascular reflexes significantly attenuated by ABVN stimulation (n=8; P<0.05), but neither by sham‐ABVN stimulation nor mechanical stimulation with the acupuncture needle applied at the HX9 acupoint, which is located at the ear tip overlying lesser occipital nerve, the auricular somatic nerve. The modulation of pressor reflexes by ABVN stimulation was significantly (P<0.05) reversed by microinjection of kynurenic acid (25 mM; n=7) into the NTS as well as naloxone (1 mM; a non‐selective opioid receptor antagonist; n=8) or gabazine (27 mM; a GABAA receptor antagonist; n=8) into the rVLM, but not by their vehicles, 0.9% normal saline. Furthermore, in rats subjected to no GD intervention, we noted that ABVN stimulation induced markedly increase in c‐Fos expression in both NTS and rVLM, compared to sham‐ABVN stimulation. Our data suggest that ABVN stimulation with manual acupuncture excites the NTS through a glutamatergic mechanism, which, in turn, attenuate excitatory cardiovascular reflexes evoked by visceral stimulation through GABA and opioids in the rVLM.Support or Funding InformationThe National Center for Complementary & Integrative Health, R01 grant AT009347 and diversity supplement award to this grant.
Signalosome nucleation enables digital innate immune proinflammatory responses
Authors: Gama Alejandro Rodriguez , Miller Tayla , Lange Jeffrey , Halfmann Randal 
Published: April 2020

Pathogen sensing in innate immune cells begins with the activation of Pathogen Recognition Receptors (PRR) that result in the formation of polymeric protein self‐assemblies known as signalosomes. The proinflammatory response resulting from signalosome formation is thought to produce a binary all‐or‐none response. How this is controlled remains unclear. Because the activation of ordered self‐assemblies like signalosomes implies a rate‐limiting nucleation step, we hypothesized that a nucleation barrier imposed by the signalosome assembly enables the digital all‐or‐none response. Here we focused on the signalosome CARD9‐Bcl10‐MALT1 (CBM), which functions downstream of fungal PRR, Dectin‐1, which activates NF‐κB. We employed DAmFRET, a recently developed method that allows to determine the frequency of protein nucleation in cells using flow cytometry. We determined that CARD9 and Bcl10 form nucleation‐limited polymers in cells with critical concentrations similar to those from in vitro studies. We then dissected the nucleation steps required for signalosome formation. Co‐expression of artificial CARD9 polymer seeds with Bcl10 resulted in the complete nucleation of Bcl10 monomeric protein. Remarkably, CARD9 seeds containing mutations that impair antifungal signaling in humans were unable to nucleate Bcl10, suggesting that a direct seeding effect of CARD9 over Bcl10 is critical for its function. We next asked whether the formation of the signalosome drives the digital activation of NF‐κB. To do so, we coupled a transcriptional fluorescent NF‐κB reporter to DAmFRET. We determined that cells containing Bcl10 assemblies strongly induced NF‐κB activation, while cells expressing a similar protein concentration in the monomeric state did not. We asked next whether mutations that alter the nucleation barriers likewise modulate NF‐κB activation. Disruption of polymer formation with mutation E53R as well as increasing the critical concentration of polymerization with mutant R36E, both impaired NF‐κB activation. In contrast, mutation R58G decreased the nucleation barrier while also exacerbating the activation of NF‐κB. Our results indicate a critical role of nucleation barriers in governing the functional outcome of signalosomes. We anticipate the impact of our work could uncover the molecular mechanism of innate immune digital proinflammatory activation, which may serve as a basis to understand the cause of autoinflammatory diseases.Support or Funding InformationStowers Institute for Medical Research
Apolipoprotein‐M bound sphingosine‐1 phosphate enhances heparan sulfate expression and endothelial nitric oxide synthase phosphorylation in cultured endothelial cells
Authors: Collignon Taylor E. , Norton Tabitha E. , Motawe Zeinab Y. , Breslin Jerome W. 
Published: April 2020

Sphingosine‐1 phosphate (S1P) is blood borne bioactive sphingolipid metabolite that has protective properties against microvascular leakage under inflammatory conditions and also can promote endothelial NO production. Previous investigations suggest that functions are mediated by S1P receptor‐1 (S1pr1) but are also limited by action of S1P on other S1P receptors. Apolipoprotein‐M (ApoM), which has been shown to act as a carrier of S1P, may help target S1P to S1pr1, producing biased S1pr1 signaling. In the current study, we hypothesized that combination of ApoM will improve the ability of S1P to enhance 1) endothelial barrier function, and 2) phosphorylation of eNOS on its activation site. We used confluent monolayers of human umbilical vein endothelial cells (HUVEC) to model the endothelial barrier. Transendothelial electrical resistance (TER), determined by electric cell‐substrate impedance sensing, served as an indicator of barrier function. Because endothelial glycocalyx health is related to barrier function, we also determined the degree of heparan sulfate expression on the cell surface, visualized by immunofluorescence microscopy of fixed, non‐permeabilized HUVEC. Western blotting was used to measure eNOS phosphorylation on its activation site (S1177). These endpoints were evaluated in control cells and cells that were treated with ApoM (0.5 μM), S1P (1 μM), or the combination of both. The results show that the addition of ApoM‐bound S1P to HUVEC significantly increased and sustained the increase in TER of the HUVEC monolayers compared to the vehicle and S1P alone. ApoM‐bound S1P also increased heparan sulfate expression on the plasma membrane and elicited enhanced phosphorylation of eNOS on S1177 compared to either ApoM or S1P alone. Collectively, the findings support that ApoM enhances the ability of S1P to promote endothelial barrier function, surface heparan sulfate expression, and activation of eNOS. These findings suggest high potential for using ApoM‐bound S1P as a therapeutic target for ameliorating endothelial dysfunction.Support or Funding InformationThis work was supported by NIH R01GM120774 and American Heart Association 18UFEL33960365. Tabitha E. Norton and Taylor E. Collignon contributed equally to this work.
Interactions of Adolescent Over‐Nutrition and Adult Alcohol Exposure on Metabolic Function in Mice
Authors: Coker Caitlin R. , Aguilar Elizabeth A. , Arnold Amy C. , Silberman Yuval 
Published: April 2020

Over‐nutrition with calorically dense diets high in fat (high fat diets, HFD) during adolescence may result in long‐lasting changes in mechanisms regulating adult insulin and glucose metabolism. These changes may be further influenced by adult alcohol (EtOH) intake leading to increased risk of metabolic disorders, such as insulin and glucose dysregulation typically seen in Type II Diabetes. We hypothesized that over‐nutrition during adolescence promotes long‐lasting perturbations in insulin signaling leading to enhancement of EtOH‐induced metabolic disruptions during adulthood. Male and female C57Bl/6J mice had ad libitum HFD or control diet from post‐natal day (PND) 28–43, after which they were all given control diet. Mice were then exposed to EtOH either one time (acute) or three times (chronic) beginning on PND70 via vapor chamber exposure to ensure equal blood ethanol concentration (BEC) levels across groups; control animals were not exposed to EtOH. Glucose and insulin tolerance tests (GTT, ITT) were performed following the last EtOH exposure. In control diet male mice, repeated EtOH exposure worsened 4 hour fasting glucose levels without altering insulin or glucose tolerance or altering 12 hour fasting glucose levels. Mice receiving adolescent HFD showed significantly increased 4 hour and 12 hour fasting glucose levels but EtOH exposure reduced these heightened levels without altering ITT or GTT results. These findings suggest that EtOH causes divergent changes in glucose control in adult mice based on history of adolescent HFD exposure which may be due to alterations in insulin and glucose counter‐regulatory mechanisms unrelated to insulin and glucose tolerance. Overall, female mice appear to be protected from adolescent HFD effects on adult metabolic dysregulation with EtOH producing divergent metabolic effects depending on length of EtOH exposure. Together, these results suggest there are sex differences in the effects of adolescent over‐nutrition and adult EtOH exposure on insulin and glucose function. Experiments are currently underway to determine if hypothalamic neuroimmune activity regulates the interaction of adolescent over‐nutrition and adult EtOH exposure on whole‐body insulin and glucose homeostasis.Support or Funding InformationF31 AA027697R01 AA026865
L‐Menthol Inhibits Cardiac Sympathoexcitation Caused by Inhaled Irritants in the Spontaneously Hypertensive Rat
Authors: Hooper Justin Shane , Taylor-Clark Thomas E. 
Published: April 2020

Inhalation of irritants (e.g. particulate matter and ozone) triggers various efferent responses through activation of transient receptor potential ankyrin 1 (TRPA1) and TRP vanilloid 1 (TRPV1) channels expressed on airway vagal afferent nerves. In the airways they cause cough and mucus secretion and in conscious, healthy animals parasympathetic‐mediated reflexes include bradycardia and atrioventricular block. However, inhalation of air pollutants including particulate matter and ozone evokes sympathoexcitation (tachycardia, hypertension) in patients with cardiovascular disease. Interestingly, selective activation of airway vagal afferent nerves in spontaneously hypertensive (SH) rats via inhalation of the TRPA1‐specific agonist allyl isothiocyanate (AITC) evoked sympathetic‐mediated tachycardia and premature ventricular contractions (PVCs) consistent with reflexes evoked by inhaled pollution in patients with cardiovascular disease.Airway reflexes such as cough have been shown to be inhibited by nasal stimulation with L‐menthol via activation of cold‐sensitive trigeminal pathways which regulate brainstem respiratory networks. Here, we investigated the cardiac reflexes evoked by inhalation of L‐menthol (150mg/ml) alone and in combination with AITC (4.7mg/ml) in conscious SH rats. L‐menthol inhalation alone had no effect on heart rate, but, when inhaled during AITC inhalation, L‐menthol selectively inhibited the AITC‐evoked tachyarrhythmia. Inhibition of the AITC‐evoked sympathoexcitatory reflexes was not seen in identical studies performed with inactive D‐menthol (150mg/ml). Therefore, we conclude that pulmonary‐cardiac reflex tachyarrhythmia are reduced by activation of nasal menthol‐sensitive pathways. This data supports the potential for prevention of aberrant irritant‐evoked pulmonary‐cardiac reflexes by nasal menthol treatment.Support or Funding InformationNIH r56
Defining Opioidergic, Glutamatergic Pontine Respiratory Patterned Neurons
Authors: Saunders Sandy , Levitt Erica 
Published: April 2020

Opioid overdose deaths have rapidly increased largely due to illicitly manufactured fentanyl. The main cause of death from opioid overdose is respiratory depression. Opioid‐induced respiratory depression is characterized by decreases in respiratory rate, chemoreceptor reflexes and impairment of the upper airway. Pharmacological inhibition of the Kölliker‐Fuse (KF) nucleus produces strikingly similar impairments to breathing as opioids, thus warranted investigation. Using the arterially perfused preparation, we have previously found that application of CTAP, a selective mu opioid receptor antagonist, directly into the KF prevents fentanyl induced apnea. Although the KF is sufficient to restore phasic motor output, it did not restore eupneic 3‐phase respiratory patterning. To determine the identity of KF neurons modulated by opioids, we performed extracellular recordings before, during and after fentanyl administration. Respiratory phase was determined by phrenic and vagal motor output. A subpopulation of inspiratory and post‐inspiratory pattered neurons stopped firing upon fentanyl administration, whereas, a variety of respiratory patterned neurons continued to fire in the presence of fentanyl, albeit some with changes in frequency. Although many medullary glutamatergic respiratory populations have been identified, the firing pattern of pontine respiratory modulated glutamatergic neurons remain unknown. In separate experiments, a promoter specific optogenetic approach was used with extracellular recording to identify Ca2+/Calmodulin‐dependent protein kinase II (CaMKIIa) expressing, presumably glutamatergic, neurons. These results suggest that KF neurons are differentially impacted by opioids and during overdose may promote aberrant glutamatergic transmission to downstream respiratory nuclei.Support or Funding InformationThis work was supported by NIH R01 DA047976.
Targeting cerebrovascular sphingosine‐1‐phosphate signaling to treat heart failure‐induced brain dysfunction
Authors: Vanherle Lotte , Uhl Franziska Elisabeth , Matthes Frank , Meissner Anja 
Published: April 2020

Chronic cardiovascular diseases increasingly emerge as risk factors for neurodegeneration. Heart failure for instance, induces a chronic reduction in cerebral perfusion. Such chronic brain perfusion deficits are frequently accompanied by cognitive decline, which not only seriously impacts the patients’ quality of life but also reduces treatment compliance. Statistically, cognitive impairment is 5 times more prevalent in heart failure patients relative to the age‐matched general population. We previously demonstrated that heart failure associates to augmented signaling of a potent bioactive phospholipid called sphingosine‐1‐phosphate (S1P). During heart failure, such enhanced S1P signaling roots from dysfunctional cystic fibrosis transmembrane regulator (CFTR) expression and activity. CFTR controls the bioavailability of cerebrovascular S1P and hence, its pro‐constrictive effects. In heart failure, reduced microvascular CFTR expression correlates with enhanced myogenic tone and reduced cerebral blood flow.In this study, we investigated the therapeutic potential of CFTR corrector compounds to normalize cerebrovascular S1P signaling and thereby, improve neurological function during experimental heart failure in mice.Systemic CFTR corrector treatment stabilized cerebrovascular CFTR expression, improved myogenic tone and rectified deficient cerebral perfusion in heart failure, without altering the systemic parameters of cardiac output or total peripheral resistance. This normalization associated to recovery of neuronal integrity (i.e., dendrite morphology and dendritic spine density) and cognitive function. The heart failure‐associated dendrite atrophy (i.e., a 22% reduction in dendrite length) was not altered in mice treated with CFTR corrector compound. Longitudinal pre‐treatment (i.e., at 10 weeks post‐infarction) and post‐treatment analyses of the same vehicle‐ and CFTR corrector‐treated HF mice confirmed that CFTR corrector treatment reversed the impaired rhino‐cortical‐dependent, short‐term retention of object familiarity caused by heart failure.Our results put forward a new mechanistic understanding of heart failure‐associated brain complications, and CFTR correctors as potential treatment option for heart failure‐associated cognitive decline.Support or Funding InformationThis work is supported by the Knut & Alice Wallenberg Foundation and the Swedish Research Council.
Transcriptional regulations induced by estradiol and intermittent hypoxia in the lungs of ovariectomized female rats.
Authors: Jochmans-Lemoine Alexandra , Ribon-Demars Alexandra , Ganouna Gauthier , Marcouiller François , Pialoux Vincent , Bairam Aida , Joseph Vincent 
Published: April 2020

Intermittent hypoxia (IH) leads to oxidative stress and inflammation contributing to tissue and cellular dysfunctions in sleep apnea patients. We showed that estradiol (E2) reduces oxidative stress markers in the brain and aorta of female rats exposed to IH (model of sleep apnea), but it remains unknown if the effects of E2 in IH occur in other tissues such as the lungs, in which E2 receptors are present. Interestingly, both IH and E2 receptors act through specific transcription factors, changing the expression of target genes, and potential interactions between these transcription networks are not known. We therefore asked if IH exposure induces oxidative stress and alters the gene expression pattern in the lungs of ovariectomized female rats, and if E2 supplementation prevents these effects. Female Sprague‐Dawley rats were ovariectomized (OVX) and implanted with osmotic minipumps delivering vehicle (OVX‐VEH), or E2 (0.5 mg/kg/day). Two weeks following surgery, the rats were exposed to room air (RA), or IH for 7 days (nadir 10% O2, 10 cycles/hour, 8 hours/day). Lung samples were used to measure the oxidative stress marker AOPP (Advanced Oxidation of Protein Products) and determine the gene expression profiles (RNA microarray, ThermoFisher Clariom S rat assay). In OVX‐VEH female rats, E2 treatment, but not the IH exposure, increased AOPP level. In OVX‐Veh rats, IH upregulated the expression of 11 genes and down regulated 5 genes, none of these genes are involved in oxidative stress. E2 in RA rats upregulated 130 genes and downregulated 112 genes including CYP1a1, a cytochrome involved in production of reactive oxygen species. In rats treated with E2, the IH exposure increased the expression levels of 270 genes and decreased the expression of 828 genes (including anti‐oxidant genes). We conclude that in the lungs of OVX female rats, IH has only limited effects on oxidative stress and on genes transcriptional pattern. E2 treatment under RA conditions apparently increases oxidative stress and has more important transcriptional effects than IH exposure. Finally, E2 treatment has profound effects on the transcriptional response to IH exposure, and helps controlling the oxidative stress response. This important interaction between E2 and IH might be relevant to better understand the cellular responses to IH and sleep apnea in women.Support or Funding InformationSupported by CIHR.
Molecular Amplification of ITS‐2 and Cox1 Regions of Paramphistomum cervi in Three Breeds of Nigerian Cattle
Authors: Jeremiah Olalekan Taiwo , Wahab Yunus Abiola , Fagbohun Olusegun Adesina 
Published: April 2020

Rumen fluke infections (paramphistomoses) in cattle are increasingly being reported. Serious issues with the parasite genus Paramphistomum are reported in sub‐tropical and tropical regions, with cases of paramphistomosis causing morbidity and mortality in ruminants.Routine laboratory diagnosis involves conventional methods, such as optical microscopy used for the morphological and histological identification of the parasites. However, the occasional difficulty of identifying parasite structures may decrease the sensitivity of such methods.Molecular technology demonstrates the presence of the parasites based on their antigenic components or Deoxyribonucleic Acid (DNA) segments. Polymerase Chain Reaction (PCR) makes it possible to perform selective amplification from complex genomes. Therefore, we describe the molecular amplification of the internal transcribed spacer 2 (ITS 2) region of the ribosomal DNA (rDNA) and Cycloxygenase region of the mitochondrial DNA (mDNA) encoding transfer Ribonucleic Acid (RNA) (tRNA‐Thr/Cox1) of adult Paramphistomum cervi worm samples by Polymerase Chain Reaction (PCR) using species specific primers: [5′‐ TGTGTCGATGAAGAGCGCAG‐3′ and 5′‐ TGGTTAGTTTCTTTTCCTCCGC‐3′] (5′‐ TGGAGAGTTTGGCGTCTTTTT‐3′ and 5′‐ CCATCTTCCACCTCATCTGG‐3′) respectively. Adult Paramphistomum cervi worm samples were obtained from the rumen of twenty bulls and twenty cows of White Fulani (n=18) Sokoto Gudali (n=13) and Red Bororo (n=9) breeds in a municipal abattoir in Ibadan city of Nigeria.The amplification of the rDNA and mDNA of the parasite at the two spacer regions yielded 500bp (ITS2=100%) and 880bp (Cox1=91.7%) bands on agarose gel electrophoresis. The results suggest Paramphistomum cervi as common rumen flukes of cattle breeds in the study location. In addition, Polymerase Chain Reaction can be used as a rapid confirmatory diagnostic tool for bovine paramphistomosis.