bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mitochondrial dysfunction increases bronchopulmonary C‐fiber excitability via PKC alpha signaling
Authors: Bahia Parmvir K , Hadley Stephen H , Taylor‐Clark Thomas E 
Published: June 2021

Airway sensory nerve excitability is a key determinant of respiratory disease‐associated reflexes and sensations such as cough and dyspnea. One notable feature of peripheral terminals of sensory nerves is that they are packed with mitochondria. Mitochondrial dysfunction and subsequent oxidative stress has been reported for a variety of cell types in inflammatory diseases. We have previously shown that reactive oxygen species (ROS) produced by Antimycin A (a mitochondrial complex III Qi site inhibitor) increase excitability in bronchopulmonary nociceptive C‐fibers. This increased excitability decreases the mechanical threshold for activation and increases action potential firing in response to a P2X2/3 agonist. This Antimycin A–induced hyperexcitability is dependent on mitochondrial ROS and is blocked by intracellular antioxidants.Given that ROS are known to activate protein kinase C (PKC), we hypothesized that this increased excitability was due to PKC activation. We used dissociated vagal ganglion neurons to study activation of the PKC isoforms: alpha, beta1, beta2, delta and epsilon in response to Antimycin‐A. Cells were stained with antibodies against the specific isoforms to determine their cellular location. Of these isoforms, only PKC alpha translocated to the region of the cell membrane in response to Antimycin A treatment.We also examined the effects of Antimycin A induced ROS production on sensory nerve terminals. We recorded action potential firing from the terminals of individual bronchopulmonary C‐fibers using a mouse ex vivo lung‐vagal ganglia preparation. C‐fibers were characterized as nociceptors or non‐nociceptors based upon conduction velocity and response to transient receptor potential (TRP) channel agonists. Antimycin A–induced hyperexcitability was inhibited by the PKC inhibitor bisindolylmaleimide (BIM) I, but not by its inactive analog BIM V. Further, this BIM I inhibition occurred at a concentration that specifically blocks activity of PKC alpha over other isoforms. In conclusion, ROS evoked by mitochondrial dysfunction caused nociceptor hyperexcitability via the translocation and activation of PKC alpha.Support or Funding InformationThis work was supported by the National Heart Lung and Blood Institute in Bethesda, USA (R01‐HL119802)This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Mouse models of human craniofacials spliceosomopathies: Are they neurocristopathies?
Authors: Jerome‐Majewska Loydie , Beauchamp Marie‐Claude , Djedid Anissa , Daupin Kevin , Clokie Kayla , Kumar Shruti , Alam Sabrina , Majewski Jacek 
Published: June 2021

Splicing, the removal of introns from pre‐messenger RNA is an essential step for expression of most genes in multicellular organisms and for expanding the number of proteins coded by genomes. Recently, exome sequencing revealed that mutations in splicing factors and small nuclear ribonucleoprotein particles (snRNPs) which form core components of the spliceosome, are responsible for craniofacial malformations. Our group used in situ hybridization to examine expression of three core components of the spliceosome: Eftud2 – mutated in patients with mandibulofacial dysostosis, Guion‐Almeida type (MFDGA); SnrpB – responsible for Cerebrocostomandibular Syndrome (CMS); and Sf3b4 which is responsible for Nager syndrome. Herein, we report expression of Eftud2, Sf3b4 and SnrpB during craniofacial development. In addition, we used CRISPR/Cas9 to generate mice with deletion (Eftud2 del) and conditional mutation of exon 2 of Eftud2 (Eftud2 flox). At embryonic days (E) 7.5 and 8.5, Eftud2 was highly expressed in ectodermal and mesodermal components of the future craniofacial region, by E9.5 expression was also found in the body wall and developing heart. Eftud2 del heterozygous mice were viable and fertile, though these embryos showed reduced levels of Eftud2 mRNA and protein. In contrast, Eftud2 del homozygous mutant embryos arrest at E3.5 and failed to grow and hatch ex vivo. To examine the requirement for Eftud2 in neural crest cells, the Wnt1‐Cre2 transgenic line was used to delete exon 2 of Eftud2 specifically in that lineage. Eftud2 flox homozygous mutant embryos carrying the Wnt1‐Cre2 transgene displayed hypoplasia of the midbrain and pharyngeal arches starting at E9.5. By E11.5, most embryos also had an open neural tube and all embryos showed exencephaly at E14.5. Cartilage preparations revealed an absence of cartilage in the head, reduction/or absence of Meckel's cartilage, and abnormal inner ear development. Since deletion of exon 2 is predicted to generate a truncated protein with partial function, our data suggest that normal levels of Eftud2 is crucial in neural crest cells for normal craniofacial development. Future studies are focused on elucidating the molecular and transcriptional basis of MFDM using this mouse model.Support or Funding InformationCanadian Institute of Health Research (MOP#142452)This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Alterations in adipocyte morphology and leucocyte infiltration in adipose tissue in mice supplemented with non‐nutritive sweeteners
Authors: Contreras Irazú , Zepeda‐Muñoz Jesus , Estrada José Antonio 
Published: June 2021

Consumption of non‐nutritive sweeteners has been related to changes in feeding behavior and energy metabolism that may lead to weight gain and insulin resistance under specific circumstances. The molecular mechanisms related to these effects have not been thoroughly determined, but chronic low‐grade inflammation in adipose tissue is known to affect leukocyte recruitment and adipocyte functions in these pathologies.The main objective of this study was to determine the morphological characteristics of adipocytes and leucocyte recruitment to gonadal and mesenteric adipose tissue in mice supplemented with commercial non‐nutritive sweetener formulations. Adult male and female BALB/c mice were randomly assigned into experimental (sucralose or steviol glycosides) and control (no supplementation) groups. Non‐nutritive sweeteners were supplemented for 6 weeks in daily drinking water. At the end of treatment, the animals were sacrificed and gonadal and mesenteric tissues were obtained to assess adipocyte morphology and leucocyte infiltration by histochemical staining and bright‐field microscopy.The results show that gonadal and mesenteric tissue from both male and female mice treated with either sucralose or esteviol glycosides had altered adipocyte morphology, with increased adipocyte size compared to controls. Additionally, a decreased number of adipocytes was observed in male mice from both sweetener groups. Male mice supplemented with steviol glycosides also had decreased leucocyte infiltration in gonadal and mesenteric adipose tissue, compared to controls.Altogether, our results suggest that frequent intake of commercial non‐nutritive sweeteners induces changes to adipocyte morphology and leucocyte infiltration in adipose tissue that may be relevant for metabolic changes associated to weight gain/loss in individuals that use these compounds in their regular diet.Support or Funding InformationConsejo Mexiquense de Ciencia y TecnologíaThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Minocycline Normalizes the Hypertension in Gastrin−/− Mice
Authors: Asico Laureano D , Hunt Jessica , Wang Xiaoyan , Wank Stephen A , Yagnesh Tailor H. , Wang Timothy C , Raj Dominic , Jose Pedro A 
Published: June 2021

The advent of cutting edge technology has paved the way for the identification of new players for sodium homeostasis and blood pressure (BP) control. The role of gut microbiome in metabolic disorders has been the subject of a growing number of metagenomic and metabolomic studies. Dysbiosis, or the alteration in the gut microbiota composition and function, affects the development of hypertension. Gut microbiota, comprised of mainly of Firmicutes (F) and Bacteroidetes (B), constantly adapt to lifestyle modifications. An increased F/B is observed in rodent and human hypertension. Minocycline selectively inhibits M1 polarization of macrophages, which results in anti‐inflammatory and anti‐hypertensive effects and normalizes the microbiome ratio and thus, the BP. We reported that the hormone gastrin responds to increased dietary sodium load and promotes the excretion of excess sodium through the interaction of renal dopamine receptors (D1R and D5R), and cholecystokinin B receptor (CCKBR), the so‐called “gastrorenal axis”. Gast−/− mice on a salt‐resistant background develop hypertension while wild‐type littermates have normal BP. Gast−/− mice have negligible gastric acid production, which results in increased bacterial survival and dysbiosis of the gut microbiota. Therefore, we tested the hypothesis that minocycline alleviates the high BP of Gast−/− mice. Gast−/− mice and their wild‐type littermates fed a high salt diet (4% NaCl) were given minocycline (50 mg/kg/day, p.o., 28 days). Results showed that minocycline decreased the high BP of conscious Gast−/− mice both at nighttime (130.7±0.4 vs. 123.2±0.3, P<0.05, Dunn's test, 4/group) and daytime (126.1±0.5 vs. 117.5±0.4 P<0.05), and the nighttime (122.4±0.4 vs. 118.4±0.5 P<0.001, Dunn's test, 4/group), but not the daytime BP of the wild‐type littermates. These results imply that inhibition of M1 macrophages decreases BP. In another set of Gast−/− mice, we tested the effect of doxycycline (43 mg/kg/day, p.o., 28 days) which selectively inhibits M2 polarization of macrophages leading to pro‐inflammatory and pro‐hypertensive effects. Doxycycline decreased the BP of conscious Gast−/− mice at nighttime (134.7±0.7 vs. 123.8±8.0 mm Hg, P<0.05, Dunn's test) and at daytime (120.7±0.6 vs. 113.1±2.8 mm Hg), conceivably by normalizing the dysbiosis expected in the knockout mice. By contrast, doxycycline increased BP in wild‐type littermates at nighttime (97.6±1.2 vs. 110.5±5.1 mm Hg) but not at daytime, which can be explained by the inhibition of the M2 macrophage polarization. Thus, the resultant hypertensive phenotype is influenced by the dynamic interplay among genetics, state of inflammation, and gut microbiota.Support or Funding InformationR01DK039308, R01HL092196, and P01HL074940This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Ion Regulation, Acid/Base Balance and Gas Exchange Interactions in Salmon Across Salinities
Authors: Damsgaard Christian , McGrath Monica , Wood Chris M. , Richards Jeffrey G. , Brauner Colin J. 
Published: June 2021

Migration between freshwater and sea water in diadromous fishes requires substantial changes in branchial, renal and intestinal regulation. Since little is known about osmoregulation in fishes in brackish water, where the gradients for water and ion movements are reduced, we investigated the organ‐specific transitions in osmoregulation across salinities, and how these may impose tradeoffs with brachial gas‐exchange and organismal acid/base‐balance. We acclimated Coho salmon to fresh‐, brackish‐, and seawater for a full year, and then measured ion‐ and acid/base‐regulation and gas‐exchange in fishes instrumented with vascular and urinary bladder cannulas. We show that glomerular filtration rate and urine production gradually decrease with increases in salinity, while drinking rates do not increase until salinities exceed isosmotic, showing that transitions in osmoregulatory function of the kidneys and gastrointestinal tract are not initiated at the same salinity. Further, we show that arterial blood gas status is identical across salinities, suggesting that branchial remodeling during salinity acclimation does not affect gas‐exchange. Lastly, we show that plasma ion composition differs across salinities and is associated with different set‐points for intra‐ and extracellular pH‐regulation. These data provide insight into compromises between ion regulation, acid/base balance and gas‐exchange in euryhaline animals across salinities.Support or Funding InformationCD is supported by the Carlsberg Foundation and the research was funded by a Natural Sciences and Engineering Research Council of Canada, Strategic Partnership 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.
Reconstructing Connective Tissue Lineage Diversification at the Single Cell Level in the Zebrafish Face
Authors: Crump Gage 
Published: June 2021

Assembly of the vertebrate face requires the precisely regulated differentiation of neural crest‐derived cells into a diversity of connective tissue fates, including cartilage, bone, and tendon/ligament cells. In order to better understand spatiotemporal regulation of this process, we are conducting a single‐cell transcriptomic analysis of neural crest‐derived cells from embryonic through adult stages. Our preliminary data reveal different trajectories for permanent cartilage, replacement cartilage, bone, and tendon/ligament cells, as well as diverse populations of undifferentiated cells in the adult face that may represent distinct progenitor populations. In the embryo, we have confirmed the presence of both multipotent and lineage‐committed cells through clonal labeling of sox10:CreER animals treated with a limiting dose of tamoxifen. We have also uncovered novel genes implicated in early lineage decisions. In particular, we find that the nuclear receptor transcription factor Nr5a2 marks cells destined to become lower jaw tendons, which we show by generating an nr5a2:GFP knock‐in transgenic reporter and performing time‐lapse microscopy. In nr5a2 mutants, tendon precursors marked by nr5a2:GFP inappropriately become cartilage cells, which results in an enlarged lower jaw cartilage that fails to properly attach to lower jaw musculature due to loss of tendons. These ongoing studies validate genomics approaches in identifying new regulators of connective tissue fates in the developing face.Support or Funding InformationNIDCR R35 DE027550This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Apolipoprotein E modulates respiratory motor plasticity following cervical spinal cord injury
Authors: Hager Lydia , Stoltz Daimen , Calulot Chris , Ritter Kyle , Silverstein Aaron , Huffman Emily , Alilain Warren 
Published: June 2021

Each year, 17,700 Americans suffer a spinal cord injury, over half of which occur at the cervical level. These high level injuries can interrupt bulbospinal neurons that innervate the phrenic motornucleus, the origin of the phrenic nerve. Loss of these descending inputs to the phrenic nerve paralyzes the ipsilateral diaphragm, leading to breathing impairments. One approach to promote recovery of breathing function is by enhancing plasticity through strengthening of synapses or activating spared but latent pathways in the spinal cord. Activation of the latent crossed phrenic pathway can lead to a form of respiratory motor plasticity known as long term facilitation (LTF), which is characterized by a prolonged increase in breathing motor output. LTF can be induced through exposure to intermittent hypoxia (IH) or by intermittently dosing the spinal cord with serotonin (5‐HT). While a portion of the spinal cord injured population responds to IH therapy with the expected increase in respiratory output, others remain non‐responders. This inconsistency indicates that variability in the human population may influence how individuals respond to treatments that aim to enhance plasticity. Therefore, we propose that genetic diversity among the SCI population could be a key factor in determining an individual's propensity for plasticity. Apolipoprotein E (apoE) is a promising candidate gene that could be responsible for this variability because one of the apoE alleles, E4, has previously been shown to reduce synaptic plasticity by decreasing expression of glutamate receptors when compared to the E2 or E3 alleles. The present study investigates the influence of human apoE4 on respiratory motor plasticity in rats following C2 hemisection. 20 weeks after injury, rats were dosed with one isoform of the human apoE protein, E3 or E4, prior to receiving intermittent 5‐HT to induce LTF. Diaphragmatic EMG recordings demonstrated that animals exposed to human apoE3 protein exhibited an increase in diaphragmatic activity ipsilateral to the injury, but this increase was abolished in E4 dosed animals. Analysis of tissue dosed with human apoE protein indicated that apoE also modulates synaptic expression of glutamate receptors, a crucial component of LTF induction. Collectively, these experiments demonstrate ApoE4's potential to inhibit plasticity following spinal cord injury, emphasizing the importance of considering genetic diversity while developing SCI therapeutics for the human population.Support or Funding InformationNational Science Foundation Graduate Research Fellowship, University of Kentucky College of Medicine Fellowship for Excellence in Graduate Research, University of Kentucky Startup FundsThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Ventilatory effects of long‐term nitrite supplementation in a rat model of obesity
Authors: Delloro Derick J , Sindler Amy L. , Van Schaeffer G. , Barnard Chris , Kadel Jacob , Bates Melissa L. 
Published: June 2021

Nitrate supplementation improves endothelial function, blood pressure, ejection fraction and overall weight. It also may attenuate the hypoxic ventilatory response (HVR) in healthy individuals. Hypoxic ventilatory response is increased in obese humans when compared to healthy individuals. Therefore, we hypothesize that HVR increases in a rat model of obesity and this increase is mitigated by nitrite supplementation. Two experiments were conducted. In the first, 12 Fischer 344 rats were broken into two groups: Rats fed a standard diet with additional nitrite supplementation (Nitrite) and rats fed a standard diet with no additional supplementation. After 2 months of nitrite supplementation, plethysmography was used to measure ventilation at oxygen levels of 21%, 15%, 12%, and 9%. In the second experiment, 21 Fischer 344 rats were divided into 3 groups: rats fed a high fat diet (HFD), rats fed a high fat diet with nitrite supplementation in their drinking water (HFD‐N), and rats fed a standard diet (Control). After 14 months of diet and nitrite supplementation, all three groups underwent identical plethysmographic measurements to the first cohort. In the first group, as expected, nitrite supplementation significantly reduced HVR. In the second group, contrary to data in humans, the obesity rat model presented a decreased HVR when compared to controls. Nitrite did not alter this obesity induced decrease in ventilation. Nitrite did cause a significant increase in VO2 when compared to both groups. Future studies are needed to determine the mechanisms behind the impact of these interventions on HVR.Support or Funding InformationThis project was funded by the College of Liberal Arts and Sciences and the Health and Human Physiology department at the university of IowaThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
The Role of Raphe‐derived Neuromodulation of the Retrotrapezoid Nucleus (RTN) in Ventilatory Chemoreflexes
Authors: Dillard Matt , Mouradian Gary C. , Hodges Matthew R. 
Published: June 2021

Excitatory neuromodulators such as serotonin (5‐HT) and Substance P are synthesized in and released from raphe 5‐HT neurons and increase the excitability of neurons within the brainstem nuclei responsible for controlling breathing. These neuromodulators have also been shown to increase the excitability of respiratory chemoreceptors, including the CO2‐sensitive Phox2b‐expressing (Phox2b+) neurons in the retrotrapezoid nucleus (RTN). However, the importance of this raphe‐derived neuromodulation of the RTN for the hypoxic and hypercapnic ventilatory chemoreflexes has not been tested in vivo. We hypothesize that unilateral ablation of serotonergic terminals within the RTN will attenuate the ventilatory chemoreflexes in vivo. To test this hypothesis, 8 week‐old female Sprague‐Dawley rats received stereotaxic injections of 5,7‐Dihydroxytryptamine (5,7‐DHT; 2 mg/ml, 2 μl vol.) unilaterally targeting the RTN to selectively lesion axon terminals from serotonergic neurons under anesthesia. Desipramine (30mg/kg, intraperitoneal) was administered 30 min prior to toxin injection to prevent axon terminal lesions of other aminergic neurons and limit the off‐target effects of 5,7‐DHT. Breathing was measured in room air, hypercapnia (7% CO2 challenge), and hypoxia (12% O2 challenge) before the lesions and then 3, 5, 7, 10, and 14 days after injection. Three days after injection, we observed a 41% decrease in the ventilatory response to hypercapnia and a 45% decrease in the ventilatory response to hypoxia, driven by a decrease in breathing frequency in both cases (N=4). However, the reduced chemoreflexes normalized over the two weeks after injection. There was no consistent effect following sham injection (N=2) of saline (2 μl vol.). These preliminary data suggest that the serotonergic terminals surrounding the RTN play a vital role in facilitating both hypercapnic and hypoxic ventilatory chemoreflexes in vivo, and support our overall hypothesis that raphe‐derived excitatory neuromodulation of the RTN is essential for ventilatory chemoreflexes in vivo.Support or Funding InformationThis work was supported by NIH HL122358.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.