bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hand2 Functions to Synergistically Activate Gli Target Genes in Mandibular Neural Crest Cells
Authors: Brugmann Samantha , Elliott Kelsey H. , Chen Xiaoting , Salomone Joseph , Chaturvedi Praneet , Gebelein Brian , Weirauch Matthew T. , Peterson Kevin A. 
Published: June 2021

The Hedgehog (Hh) pathway has been well‐studied and implicated in neural crest cell (NCC) survival and facial patterning; however, the mechanism(s) by which the transcription factors (TFs) of the pathway, the Gli TFs, orchestrate Hh signal transduction remains elusive. For example, Gli ChIP‐seq data from NCCs in the developing mandibular prominence (MNP) reveal that the presence of a peak is not sufficient to predict a Gli “target.” In light of these data and previous studies suggesting Gli proteins interact with co‐factors, we performed genome‐wide analyses to identify motifs that frequently appear near Gli binding regions (GBRs). These analyses revealed that E‐box motifs (bHLH TF binding sites) were significantly enriched (p=0.001) within Gli ChIP‐seq peaks compared to random sequences. Additionally, ChIP‐seq peaks for Hand2, a bHLH TF known to be necessary for MNP development, were 111‐fold enriched within Gli peaks. A comparison of Hand2f/f;Wnt1‐Cre and Gli2f/f;Gli3f/f;Wnt1‐Cre MNP phenotypes shows striking similarities, which in conjunction with the significant overlap of Gli and Hand2 co‐occupied genomic regions suggests these two proteins may work in tandem to influence Gli target gene expression. Interrogation of DNA motifs within genomic locations occupied by Gli and Hand2 together versus those occupied by Gli alone revealed the existence of two distinct types of GBRs: a ‘canonical’ GBR defined by the presence of a medially located A (GACCACCC), and a ‘deviant’ GBR defined by a T in the medial position (GACCTCCC). Interestingly, the ‘canonical’ GBR is 19‐fold enriched (p<10−136) in Gli3 peaks without a Hand2 peak, whereas it is only 3‐fold enriched (p<10−47) in Gli3 peaks that contain a Hand2 peak. To test if these distinct GBRs convey biological relevance, we identified canonical and deviant GBRs within Gli and Hand2 ChIP‐seq peaks of Gli targets important for mandibular development and linked them to reporter constructs transfected into 09–1 cells. We found that Hand2 and Gli utilize a deviant GBR to synergistically activate Gli targets including Foxd1 and Foxd2. In sum, our work establishes insight into the existence of a sequence‐dependent mechanism for Gli target gene regulation in which molecular accomplices may be necessary for optimal transcription of Gli targets in NCCs of the developing MNP.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Sex‐Specific Alterations in LPS‐Induced Peripheral and Central Inflammation in Adult Offspring Exposed to Gestational Intermittent Hypoxia: Potential Regulation by miR‐146
Authors: Wang Tao , Kiernan Elizabeth , Ewald Andrea , Baker Tracy , Watters Jyoti J 
Published: June 2021

The prevalence of obstructive sleep apnea (OSA) and concomitant intermittent hypoxia (IH) in pregnant women is rising in parallel with the obesity epidemic. IH causes profound inflammation, and it is well‐established that maternal immune activation can lead to detrimental outcomes in her offspring. Although in recent years the acute consequences of maternal OSA on the health of both the mother and the newborn have become better appreciated, little remains known about the potential long‐lasting consequences to the offspring in adulthood. Given the effect of inflammation on the neural control of breathing, we studied the consequences of gestational intermittent hypoxia (GIH) on the central and peripheral immune responses of adult male and female offspring. We exposed rat dams to IH from gestational days 10–21 (8hrs/day, 2 min cycles alternating between 10.5% O2 and 21%O2, mimicking the desaturation and resaturation kinetics of human OSA). We challenged the adult offspring with a peripheral LPS injection (1 mg/kg i.p., 3 hrs) and assessed neural (whole brain homogenates) and peripheral (spleen) cytokine gene expression. We found that GIH gene‐specifically enhanced LPS‐induced neuroinflammation in adult offspring of both sexes. Conversely, while LPS‐induced peripheral inflammation was unchanged in GIH male offspring, it was strongly attenuated in GIH females, suggesting that the central and peripheral immune responses are differentially impacted by GIH, and that these effects differ by sex. Because microRNAs (miRNAs) are critical regulators of the immune response, we tested the hypothesis that miRNAs are differentially expressed in male and female GIH offspring. In spleens from adult GIH offspring, we screened the levels of several immunoregulatory miRNAs. Interestingly, miR‐146, a strongly immunosuppressive miRNA, was highly upregulated in female spleens. We suggest that augmented miR‐146 levels suppress peripheral immune responses to an inflammatory challenge in GIH offspring, and that miR‐146 levels will be reduced in the brain where neuroinflammation is enhanced in GIH offspring. Studies are underway using lentiviral‐mediated manipulation of miR‐146 activity to more directly test this hypothesis, and to understand how central and peripheral inflammation are ultimately regulated in the context of GIH. Regulating miR‐146 expression in adults exposed to maternal OSA in utero may represent a novel therapeutic target to control the detrimental consequences of aberrant inflammatory signaling.Support or Funding InformationSupported by NIH R01 NS085226 and HL105511, and a Wisconsin Alumni Research Foundation UW2020 grant.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Microglia Modulate Changes in Dorsal Motor Nucleus (DMNV) Neuron Excitability Following Sustained Hypoxia Exposure During a Critical Period of Neonatal Development
Authors: Mayer Catherine , Mac Farlane Peter 
Published: June 2021

We showed previously that the respiratory neural control system exhibits a lethal vulnerability to sustained hypoxia (SH) exposure during the second postnatal week of life (SH=11% O2, postnatal (P) day 11–15). The vulnerability was associated with increased microglia expression and decreased serotonin (5‐HT) expression in the dorsal motor nucleus of vagus (DMNV), an area of the brainstem containing vagal preganglionic neurons which provide parasympathetic outflow to the heart (and viscera). We hypothesized that this increased microglia expression was associated with increased activity of DMNV neurons and that this could be reversed by treatment with minocycline, an inhibitor of microglia activation. We used whole‐cell patch clamp recordings to examine the excitatory properties of DMNV neurons in neonatal (P16) rats treated with SH from P11–P15. A subset of these animals received subQ injections of minocycline on P11, P13, and P15. SH exposure increased the frequency and amplitude of spontaneous EPSCs in DMNV neurons compared to normoxic (NX) rats; rise time, decay time, and area of the spontaneous EPSC's did not differ between groups. Minocycline treatment during SH prevented the increase in frequency and amplitude seen with SH exposure alone. In conclusion, neurons from the DMNV of SH exposed animals exhibit increased excitability suggesting increased vagal tone in vivo – an effect that appears modulated by microglia. These data may be important to understanding the potential effects of inadequate oxygenation on parasympathetic modulation of heart rate during particularly vulnerable periods of cardiorespiratory development.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
The Transcriptomic Profiles of Microglia from Respiratory Control Centers in Adult Offspring Exposed to Gestational Intermittent Hypoxia Differ by Sex and CNS Region
Authors: Ewald Andrea C , Kiernan Elizabeth A , Baker Tracy L , Watters Jyoti J 
Published: June 2021

The in utero environment is well‐known to influence CNS development and microglial function, effects that can last into adulthood. However, fetal brain reprogramming has never been evaluated in the context of sleep‐disordered breathing (SDB) during pregnancy, despite its alarming increase in recent years and the detrimental consequences to the newborn. Here, we tested the hypothesis that maternal exposure to intermittent hypoxia during pregnancy would alter the microglial transcriptome of the adult offspring in CNS regions critical for respiratory neural control. To do this, we utilized a rat model of gestational intermittent hypoxia (GIH) in which dams received intermittent hypoxia (2 min alternating 10.5%/21% O2) or normoxia (2 min alternating 21% O2/21% O2; GNX) for 8 hrs/day from gestational days 10–21. Male and female offspring were grown to adulthood (8–12 wks old) and then challenged with vehicle (HBSS) or lipopolysaccharide (LPS; 1mg/kg, 3h) in order to assess transcriptional responses in both basal and inflammatory conditions. Microglia were immunomagnetically isolated from adult brainstem and cervical spinal cord and total RNA harvested. Sequencing libraries were generated using NEBNext Ultra RNA Library Prep Kit and Illumina paired‐end RNA‐sequencing was performed. The reference genome was built using Bowtie and clean reads were aligned to the reference genome using TopHat. FPKM quantification, differential gene expression levels, and gene ontology analyses in brainstem and spinal cord microglia from GNX and GIH male and female offspring were performed using the DESeq or GOSeq R packages, respectively. Preliminary bioinformatics analyses indicate strong differences in the normal transcriptomes of GNX brainstem and cervical spinal cord microglia. Further, we observed significant sex differences both in basal and LPS‐stimulated microglial gene expression in adult GNX microglia from both CNS regions. Interestingly, GIH potently up and down‐regulated more genes in female spinal cord microglia than in male, and effects of GIH were not detected in the brainstem in either sex. Together, these data suggest that the offspring microglial transcriptome can be changed by maternal exposure to intermittent hypoxia and that these effects can persist into adulthood. Given the importance of microglia‐neuron communication in the neural control of breathing, these microglial gene alterations may impact respiratory and brain immune function in the adult offspring.Support or Funding InformationSupported by NS085226, HL105511 and Wisconsin Alumni Research Foundation UW2020 grant.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Increasing the excitability of V2a neurons restores diaphragm function following spinal cord injury
Authors: JENSEN VICTORIA N , Alilain Warren , Crone Steven A 
Published: June 2021

We hypothesize that ipsilaterally projecting glutamatergic V2a neurons in the ventral spinal cord and brainstem contribute to recovery of diaphragm function following injury. To test our hypothesis, we used a transgenic mouse line that expresses DREADDs in V2a neurons in order to increase their excitability via activation of Gq signaling pathways following injection of the drug‐like molecule clozapine‐N‐oxide (CNO). We performed a high level C2 hemisection (C2Hx) spinal cord injury to paralyze the diaphragm ipsilateral to injury. Electromyography (EMG) recordings of the ipsilateral diaphragm confirmed paralysis. However, increasing V2a neuron excitability by intraperitoneal injection of CNO restored rhythmic burst activity to the paralyzed diaphragm within hours or days after injury. Moreover, the contralateral (uninjured side) diaphragm is able to maintain regular rhythmic breathing when V2a neuron activity is altered. These results indicate that targeting Gq signaling pathways in V2a neurons has the potential to restore function to respiratory muscles following spinal cord injury without significant adverse side effects on respiratory rhythm generation.Support or Funding InformationUK Center for Clinical and Translational Science, Cincinnati Children's Hospital Medical Center Division of Neurosurgery, Albert J. Ryan Fellowship, University of Cincinnati Neuroscience Graduate ProgramThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
No Effect of Adenosine or Serotonin Receptor Blockade on the Biphasic Hypoxic Ventilatory Response of Neonatal Rats
Authors: Memishian Wendy , Turnage Mary Buford , Bavis Ryan W. 
Published: June 2021

Newborn mammals generally exhibit a biphasic hypoxic ventilatory response (HVR) in which an initial increase in ventilation is followed by a progressive decline toward (or below) baseline. Previous studies have implicated a variety of inhibitory neurotransmitters and neuromodulators in the secondary ventilatory decline in one or more animal models. Here we investigated the contribution of adenosine receptors and serotonin receptors to the biphasic HVR in neonatal (P3‐5) rats. The HVR (10% or 12% O2) was measured by head‐body plethysmography after administration of an adenosine receptor antagonist (40 mg/kg caffeine citrate or 30 mg/kg aminophylline), a serotonin receptor antagonist (0.5 or 1.0 mg/kg SDZ SER 082 fumurate, 2.5 or 4.0 mg/kg methysergide maleate, or 0.5 mg/kg RS 127445 HCl), or the appropriate vehicle (n=5–22 per group). All drugs were administered intraperitoneally 30–45 minutes prior to recording the HVR. None of the drugs altered baseline ventilation, the magnitude of the HVR, or the shape of the biphasic HVR (Drug and Drug × Time, all P>0.05). Although the role of serotonin in the biphasic HVR is not well established, previous studies have supported a role for adenosine receptors in hypoxic ventilatory decline in neonatal rats (e.g., Bairam et al., Respir. Physiol. Neurobiol. 185: 57–66, 2013). The reason for these contrasting results is not known.Support or Funding InformationSupported by NIH grant P20 GM‐103423 (Maine INBRE).This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
The Interaction of TRPV1 and EP3 Receptors in Cough Response of Guinea Pig
Authors: Gao Xiuping , Zhuang Jianguo , Zhao Lei , Wei Wan , Xu Fadi 
Published: June 2021

Bronchopulmonary C‐fibers (PCFs) play an important role in cough generation. An interaction of TRPV1 and EP3 receptor in cough response has been reported, but the relevant mechanisms are not fully investigated. This study aims to identify: 1) the co‐localization of the two receptors in vagal pulmonary C‐neurons of the nodose/jugular ganglia; 2) the dependency of cough responses to citric acid (CA) on EP3 receptors and that to prostaglandin E2 (PGE2) on TRPV1 as well as the corresponding cough tachyphylaxis; and 3) the dependency of CA‐ or PGE2‐triggered currents on TRPV1 or EP3 receptors in the vagal pulmonary C‐neurons. Guinea pigs (GPs) were used. Immunohistochemical approach was applied to label TRPV1 and/or EP3 receptors in vagal pulmonary neurons retrogradely traced by DiI (Series I). Conscious GPs were exposed to aerosolized CA (150 mM) or PGE2 (0.43 mM) w/wo pretreatment of aerosolized antagonist (JNJ 17203212 or capsazepine for TRPV1 and L‐798106 for EP3 receptor) (Series II). In addition, some GPs were exposed to the same CA or PGE2 twice with a 3‐hour interval (CA‐CA and PGE2‐PGE2) and others to CA followed by PGE2 or vice versa (CA‐PGE2 and PGE2‐CA) (Series III). Whole‐cell patch clamp was employed to test the effects of above antagonists on the currents triggered by CAP or PGE2 (Series IV). The results were summarized as follows. 1) Almost all EP3‐labeled vagal pulmonary sensory neurons co‐expressed TRPV1 receptors with smaller cell sizes (< 20 μm) and the population of these neurons occupied 1/3 of the neurons single‐labeled by TRPV1. 2) TRPV1 antagonist significantly reduced the cough number evoked by PGE2, but EP3 antagonist did not affect that by CA. 3) Compared to the CA‐induced cough, the PGE2‐induced cough has extremely higher tachyphylaxis. In sharp contrast, no tachyphylaxis was observed in CA‐PGE2 and PGE2‐CA groups. 4) Both CA‐currents and PGE2‐currents were recorded in the same cells of some vagal pulmonary C‐neurons with the former significantly reduced by TRPV1 antagonist and the latter decreased by EP3 antagonist; PGE2 significantly strengthened the CA‐currents and this effect was abolished by EP3 antagonist; and most interestingly, the TRPV1 antagonist significantly diminished the PGE2‐currents. In conclusion, PGE2 inhalation evokes cough likely via acting on a subgroup of vagal pulmonary sensory TRPV1 neurons co‐expressing EP3 receptors. TRPV1 receptors of these neurons are able to facilitate PGE2‐evoked cough via interacting with EP3 receptors. Endogenous PGE2 seems to have a limited impact on CA‐evoked cough, while exogenous PGE2 is capable of amplifying TRPV1‐mediated respiratory and vagal pulmonary C‐neural responses. Moreover, their interaction fails to affect the cough tachyphylaxis.Support or Funding InformationNIH HL119683This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Liquiritin Apioside (LA) Attenuates Apneic Responses to Stimulation of Laryngeal Chemoreceptors but not Mechanoreceptors in Rat Pups
Authors: Wei Wan , Gao Xiuping , Zhao Lei , Zhuang Jianguo , Jiao Yang , Xu Fadi 
Published: June 2021

Laryngeal chemoreceptors (TRPV1; acid‐sensitive ion channels, ASIC; and osmotic receptors) and mechanoreceptors play an important role in triggering apnea, especially in infants, which has been related to the pathogenesis of sudden infant death syndrome (SIDS). LA, a main flavonoid component of licorice widely used as an antitussive herbal medicine in China even via taking lozenge, is reportedly able to suppress cough responses to inhalation of aerosolized capsaicin (a selective stimulant of TRPV1) in conscious guinea pigs. These results imply an inhibitory impact of LA on airway TRPV1; however, it remains unknown whether LA affects the apneic responses to selective stimulation of these laryngeal receptors, and if so whether its effect is achieved by directly acting on the superior laryngeal nerve (SLN). In anesthetized and spontaneously breathing rat pups, the following stimulations were applied after intralaryngeally loading 50 μl LA (10 μg/μl) and vehicle for 10 min. Intralaryngeal perfusion of capsaicin (CAP), hydrochloric acid solution (HCl), and distilled water (DW) for 10 s was employed to selectively stimulate local TRPV1, ASIC, and osmotic receptors respectively. Intralaryngeal delivery of air‐puff (AP for 2 s) with peak pressure at ~40 mmHg was utilized to stimulate laryngeal mechanoreceptors. The results showed that CAP, HCl, DW, and AP triggered an immediate apnea with TE prolonged by 24‐, 17‐, 18‐ and 3‐fold respectively. LA per se did not alter baseline ventilation but shortened the CAP‐, HCl‐, and DW‐evoked apneic durations by 75%, 68%, and 54% respectively (P < 0.01) with little effect on the apneic response to AP. To determine the direct effect of LA on the SLN, the latter was bilaterally isolated and pretreated by perilaryngeal LA treatment (10 μg/μl) or vehicle for 20 min. Perilaryngeal LA treatment produced a similar inhibition in CAP‐ and HCl‐induced apneic responses but failed to change DW‐induced apnea. Our results, for the first time, suggest that LA applied on the laryngeal mucosa depresses the stimulatory effects of CAP, HCl, and DW on laryngeal chemoreceptors in which CAP and HCl are capable of directly act on TRPV1 and ASIC of SLN. This finding may extend the therapeutic use of LA to treat a subgroup of SIDS victims with laryngeal disorders and explain, at least partially, the antitussive effect of LA due the critical role of laryngeal sensory afferents in cough initiation. The cellular mechanisms underlying this inhibition are warranted for further investigation.Support or Funding InformationNIH HL119683This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
The CO2/pH Chemosensitivity of Locus Coeruleus Neurons Is Increased in the Streptozotocin‐Model of Alzheimer's Disease
Authors: Vicente Mariane Cristine , Gargaglioni Luciane Helena , Ostrowski Tim Daniel 
Published: June 2021

Patients with Alzheimer's disease (AD) develop pathological changes in the Locus Coeruleus (LC), an important pontine nucleus involved in respiratory control and central chemoreception. In addition, AD patients have breathing disturbances that may be related to LC dysfunction. Here, we tested the electrophysiological properties of LC neurons in a model for AD. Sporadic AD was induced in rats (6–7 weeks) by intracerebroventricular injection of streptozotocin (STZ; 2 mg/kg). After 14 days following injection, LC neurons were recorded using the patch clamp technique and tested for CO2 chemosensitivity (10% CO2, pH = 7.0).Hypercapnic exposure lowered current‐evoked spike discharge in the majority of LC neurons (~60%) when compared to baseline responses. The remaining cells either increased spiking (~20%) or did not respond (~20%) to CO2. Within the cell group that was inhibited by hypercapnia, baseline spike discharge to current injection was similar between control and STZ rats. These responses decreased significantly in both groups when exposed to 10% CO2 (bsl vs. 10% CO2: CTL, p=0.003, n=8 and STZ, p=0.001, n=9). The CO2‐induced decrease in spike discharge of the STZ group was significantly lower when compared to control (CTL vs. STZ, p=0.038), indicating greater sensitivity to hypercapnia. However, we observed no difference in resting membrane potential and input resistance (Ri, resistance across the cell membrane) between groups at baseline and CO2. Despite lack of difference between groups, within the STZ group Ri decreased significantly with hypercapnia (bsl, 126.5 ± 14.9 MΩ vs. 10% CO2, 98.4 ± 8.2 MΩ; p=0.01), indicating ion channel opening when exposed to CO2. Analysis of the current‐voltage relationship only showed a significant decrease in the steady state current under CO2 (bsl vs. 10% CO2: CTL, p=0.002, and STZ, p=0.001,), which had a similar magnitude in both groups. Close analysis of action potential (AP) shape (spike threshold, peak, slope, peak to anti‐peak) showed no difference between groups. Within the STZ rats, however, spike threshold was significantly shifted to more positive potentials when exposed to CO2 (−39.6 ± 1.9 mV vs −34.8 ± 2.2 mV, p=0.01). This shift in spike threshold likely contributes to the pronounced decrease in spike discharge in the STZ group during hypercapnic conditions.In summary, our data suggest that the majority of LC neurons in adult rats are inhibited by CO2. Further, the STZ‐treated group exhibits a greater sensitivity to CO2, possibly due to an increased spike threshold and opening of additional, yet unidentified membrane channels. A decreased excitability of LC neurons may play a role in the respiratory dysfunction observed in patients with AD.Support or Funding InformationFAPESP 2017/21750‐9 (MCV); ATSU seed money (TDO)This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.