bluuebunny/crossref_metadata_2025_split huggingface dataset:
Myeloid Cell Recruitment and Activation Following Ozone Exposure in a Murine Model of Mutant Surfactant Protein‐C Pulmonary Dysfunction
Authors: Venosa Alessandro , Tomer Yaniv , Kopp Meghan , Gow Andrew J , Laskin Debra L , Beers Micheal F 
Published: June 2021

The missense isoleucine to threonine substitution at position 73 [I73T] in the Surfactant Protein‐C [SP‐C] gene [SFTPC], an alveolar type‐2 cell [AT2] restricted protein, has been linked to sporadic and familial cases of idiopathic pulmonary fibrosis (IPF). We have developed a hypomorphic SP‐CI73T mouse model which expresses 20% of wild‐type SP‐C output. In this setting, AT2 cells mistraffick pro‐SP‐C on the plasma membrane and temporally acquire a late block in AT2 cell macroautophagy. This is associated with age‐dependent enlargement of alveolar septae, AT2 cell hyperplasia and minor inflammatory cell accumulation, beginning at 16 wk of age. Ozone is a ubiquitous air pollutant that causes parenchymal injury and monocyte/macrophage dominant inflammation. Clinically, acute exposure to ozone is known to exacerbate respiratory injury in susceptible population (i.e. asthma). Therefore, we tested whether SP‐CI73T dysfunction is associated with susceptibility to ozone induced injury (0.8 ppm, 3 h) in young (8–12wk) and aging (52 wk) mouse cohorts. We found that young WT mice exposed to ozone did not cause significant alterations in bronchoalveolar lavage (BAL) fluid immune cell composition or cell numbers at 24 h. Conversely, differential analysis of cytospins and flow cytometry analysis of tissue digest showed increased cell counts with significant neutrophilia and lymphocyte accumulation in SP‐CI73T mice. Analysis of aging cohorts confirmed significant deterioration of lung architecture in air‐exposed 52 wk SP‐CI73T mice. Ozone exposure was associated with histological evidence of perivascular edema and immune cells influx. BAL total protein analysis also showed increased epithelial‐vascular barrier disruption at 24 h and 48 h. Taken together, our findings support the concept that epithelial dysfunction driven by mutant SP‐CI73T expression is associated with increased susceptibility to environmental toxicant and that these effects are heightened with aging.Support or Funding InformationGrant support: P30ES013508 (MFB), VA 1I01BX001176 (MFB), ES004738 (DL), ES005022 (DL).This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Effects of Chlorogenic Acid on Reactive Oxygen Species and Neutrophil Extracellular Trap Formation
Authors: Foley Anna , Abouelkheir Mahmoud , Petreaca Melissa 
Published: June 2021

Innate immune cells such as neutrophils respond to signals at sites of infection or tissue damage by moving to the affected area and eliminating microbes by producing reactive oxygen species (ROS), very reactive molecules that damage and kill microbes, and neutrophil extracellular traps (NETs), expelled DNA chromatin and histones that form net‐like structures with sticky surfaces that can trap and kill microbes. Although ROS and NET formation are needed to prevent life‐threatening infections, excessive inflammation can lead to host tissue damage and dysfunction, and, indeed, does so in many types of diseases. Chlorogenic acid (CGA), a dietary polyphenol found in coffee, has antioxidant and potentially anti‐inflammatory effects. The possible anti‐inflammatory impacts of CGA have important medical implications due to the widespread, global availability of coffee, even in areas with reduced access to affordable and accessible pharmaceuticals. We tested the impacts of CGA on PMA‐induced ROS and NET formation in neutrophil‐like HL‐60 cells. We found that CGA functions as an antioxidant that significantly decreases PMA‐induced ROS production cells in these cells without affecting the production of superoxide or the formation of NETs. This suggests that CGA may function as an antioxidant in vivo and thereby reduce inflammation by decreasing the tissue‐damaging functions of ROS in inflamed tissues. We are currently investigating this idea further by elucidating the impact of chlorogenic acid on Lipopolysaccharide (LPS)‐induced ROS production by human polymorphonuclear neutrophils (PMN) to determine whether CGA maintains similar effects in a more physiological system.Support or Funding InformationDePauw University and the Science Research Fellows programThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Effect of Aquaporin 5 and Carbonic Anhydrase II on the Diffusion of CO2 in Xenopus Oocytes
Authors: Wang Dengke , Boron Walter F 
Published: June 2021

Transport of gases across the plasma membrane is not only dependent on the permeability, but also the concentration gradient. Carbon dioxide (CO2) is one of the most important physiological gases in the human body, but undergoes slow hydration/dehydration reactions. As a gas channel, human (h) AQP5 can accelerate the diffusion of CO2 by increasing membrane permeability to CO2. Carbonic anhydrases (CAs) also can accelerate the transport of CO2 across the membrane by maximizing the CO2 gradient via the consumption/production of CO2. Here, by measuring the maximal extracellular‐surface pH increase (DpHS) caused by the introduction of extracellular CO2/HCO3− at constant extracellular pH (pHo), we obtain a semiquantitative index of the CO2 influx into Xenopus oocytes. On Day 1, we injected oocytes with the cRNA encoding hAQP5 (or H2O as a control). On Day 4, we injected purified bovine CA II protein in Tris buffer (or Tris buffer as a control). In agreement with previous reports, both hAQP5 and CA II individually increase DpHS vs. H2O/Tris‐injected control oocytes. However, the effect of CA II alone in raising DpHS even at very high CA II concentrations (1000ng/oocyte), is not as effective as AQP5 alone. Most likely, the native CO2 permeability of Xenopus oocytes is so low that it limits transmembrane CO2 diffusion. Interestingly, injection of CA II—even at CA II levels so low that they barely increase DpHS in oocytes not expressing AQP5—into oocytes expressing AQP5 causes DpHS to increase substantially vs. AQP5 oocytes without CA II. Our data suggest that when membrane CO2 permeability is low, the effects of AQP5 and CA on CO2 fluxes are supra‐additive.Support or Funding InformationNIH U01‐GM111251, N00014‐15‐1‐2060, N00014‐16‐1‐2535This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Lymph nodes harbor compartments of substantial acidity
Authors: Swietach Pawel , Wu Hao , Estrella Veronica , Enriquez‐Navas Pedro , Abrahams Dominique , Ibrahim‐Hashim Arig , Reshetnyak Yana , Luddy Kimberly , Damaghi Mehdi , Pilon‐Thomas Shari , Gillies Robert J 
Published: June 2021

The effector function of T cells (e.g. secretion of cytokines) is profoundly inhibited by low extracellular pH (pHe), such as that encountered in solid tumors. Because the effect of acid on T cells is so robust, we hypothesized that it plays a role in normal physiological function. A plausible location where this acid signaling could take place physiologically is in lymph nodes (LNs), where T cells become activated, but must refrain from secreting inflammatory cytokines to avoid damaging the host organ. While LNs are known to be hypoxic1, measurements of their pH are lacking. We show, using four different approaches, that LNs have acidic compartments, reporting pHe in the range 6.2–6.8. LN pHe was interrogated using microelectrodes2, chemical exchange saturation transfer (CEST) MRI3, imaging with pH‐low inserting peptide (pHLIP)4, and intravital imaging of dextran‐conjugated cSNARF1, a pH sensitive fluorescent dye delivered by tail vein or footpad injection5. Furthermore, intravital imaging and pHLIP‐immunostaining showed that this acidity was restricted to subcortical regions, known to contain antigen‐presenting dendritic cells and lymphocytes. LN acidity was not washed‐away with NaHCO3 administered orally, suggesting that it is unlikely to arise from diffusion‐limited retention of acid. Our findings suggest that an acidic milieu in LNs is involved in the fundamental process of developing adaptive immunity.Support or Funding InformationFunding: PS: Fulbright Scholarship (US Department of State) RJG: Grant from NCI (R01CA077571)This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Effects of High Environmental CO2 Levels on Atlantic Salmon Post‐Smolts
Authors: Gharbi Naouel , Mota Vasco , Terjesen Bendik Fyhn , Kolarevic Jelena , Ytteborg Elisabeth , Ebbesson L.O.E , Handeland Sigurd O , Nilsen Tom Ole 
Published: June 2021

Atlantic salmon has demonstrated the capacity to physiologically acclimate when exposed to increased pCO2 levels in aquaculture flow‐through systems. Less is known about tolerance to increased pCO2 in Recirculation Aquaculture System (RAS). In the present study, Atlantic salmon post‐smolt in a RAS were kept at 12 ppt (12°C) and exposed to six different pCO2 levels ranging from <5 mg/L (PCO2<1.83 mm Hg), 12 mg/L (PCO2=4.40 mm Hg), 19 mg/L (PCO2=6.94 mm Hg), 26 mg/L (PCO2=9.50 mm Hg), 33 mg/L (PCO2=12.06 mm Hg) and 40 mg/L (PCO2=14.61 mm Hg). After 12 week treatments fish were transferred to full strength seawater with the lowest tested pCO2 level. We found that post‐smolts demonstrated a classic transient physiological compensatory response to cope with elevated pCO2, despite a clear and persistent decrease in growth rate when reared above 19 mg/L CO2. After twelve weeks of variable pCO2 exposures post‐smolt were challenged with rapid changes from high (40 mg/L) to low (5 mg/L) pCO2 levels and vice‐versa. Here we also will present physiological compensatory responses 1 and 24 hours and up to 6 days following rapid changes in pCO2 exposure.Support or Funding InformationCenter for Research Based Innovation, “CtrlAqua” Project Number 237856/030This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
How Does Temperature Affect Primary Barrier Functions in Atlantic Salmon (Salmo Salar L.) Post‐Smolts?
Authors: Tang Patrik , Nilsen Tom Ole , Gharbi Naouel , Osberg Camilla , Handeland Sigurd , Ebbesson Lars , Käkelä Reijo , Tronci Valentina , Pedrosa Cindy , Balseiro Pablo , Stefansson Sigurd 
Published: June 2021

Environmental temperature has a considerate impact over near all aspects of physiology in both wild and cultured salmonids. In addition to climate change, insight regarding the effects of temperature over physiology is crucial for the aquaculture sector, as temperature differences during the seaward transfer of fish from (semi‐) closed containment systems to open sea pens may be great and ultimately dependent on the prevailing season. For example, transferring of fish will likely occur towards higher temperatures during the summer months and lower temperatures during winter months. Further, open‐pen rearing of post‐smolt salmonids occur throughout the year at varying seasonal temperatures. Due to these temperature differences, it is therefore important to know how temperature influences tissue characteristics and modulates physiological functioning and adaptation, which processes maybe challenged during stress, thereby contributing to the stress response and overall robustness of the fish. Here we present how differences in temperature, ranging from 4°C to 18°C, affects Atlantic salmon (Salmo salar L.) post‐smolt primary barrier composition and functioning of osmoregulation in seawater. Our results suggest that primary barrier characteristics change with shifting temperatures, resulting in new physiological set points to match osmoregulatory demand in those conditions. Further, we elucidate how prior acclimation history affects the capacity of these barrier systems to respond when confronted by an additional acute stress. In this study, we investigated key changes in gill and skin phospholipid (PL) and fatty acid (FA) compositions utilizing electrospray ionization‐tandem mass spectrometry (ESI‐MS/MS) and gas chromatography (GC‐FID), in concert with qPCR expression profile changes of vital genes involved in osmoregulation, thereby aiming to understand how these correlate to changing patterns in primary barrier performance at different temperatures.Support or Funding InformationCenter for Research Based Innovation, “CtrlAqua” Project Number 237856/030This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Ablation of PHOX2B‐Derived Astrocytes Results in Neuronal Dystrophy‐Like Neuropathology in the RTN
Authors: de Melo e Silva Talita , Czeisler Catherine M , Fair Summer R , Alzate‐Correa Diego , Takakura Ana C T , Moreira Thiago S , Otero Jose J 
Published: June 2021

The transcription factor Phox2b is a regulator of the autonomic nervous system development and is especially expressed by respiratory circuits involved in chemosensory integration, as neurons of solitary tract nucleus (NTS) that relay information from peripheral chemoreceptors to the ventral respiratory column, and by central chemoreceptors located in the retrotrapezoid nucleus (RTN). In addition to neurons, recent studies show that astrocytes from ventral medullary surface also detect PCO2 increase, and contribute to respiratory drive. Since PHOX2B biased progenitor cells generate astrocytes that have a developmental connection with RTN neurons, the aim of this study is determine the extent to which selective ablation of these astrocytes affect synapse integrity in the retrotrapezoid nucleus. We utilized the astrocyte ablation technique described by Tsai et al., 2012. In this model, the astrocyte‐specific ALDH1L1 promoter induces GFP expression in the absence of cre recombinase, and in the presence of cre recombinase expresses diphtheria toxin A (DTA). We interbred ALDH1L1loxp‐GFP‐STOP‐loxp‐DTA mice to PHOX2Bcre mice. Transmission electron photomicrographs were captured from the RTN/VLM area and morphometric analysis was performed using FIJI. We noted that axon terminals in the mutants (PHOX2Bcre, ALDH1L1loxp‐GFP‐STOP‐loxp‐DTA) were on average larger in area and perimeter. Furthermore, we noted an increase in the percentage of axon terminals showing autophagic vacuoles/phagosomes. The proportion of axon terminals with other organelles, including mitochondria and dense core neurosecretory vesicles, was not different between groups. In summary, PHOX2B‐derived, astrocyte ablated mice show synaptic pathology characterized by dysmorphic neuroaxonal morphology, suggesting an underlying defect in the afferent input into the RTN. These data suggest that PHOX2B‐derived astrocytes may play a role in regulating the synaptic integrity of neuronal inputs into RTN neurons. Other experiments are being performed in order to elucidate if the cell body of these neurons is located in the commissural NTS, and also, if PHOX2b derived astrocytes depletion can imply local regulation of presynaptic autophagy, which can lead to neurodegeneration and breathing impair.Support or Funding InformationFAPESP and NIHThis 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 the Cerebellum on the Control of Tracheobronchial Cough in Spontaneously Breathing Cats
Authors: Musselwhite M Nicholas , Shen Tabitha Y , Rose Melanie J , Reed Mitchell D , Poliacek Ivan , Pitts Teresa , Bolser Donald C 
Published: June 2021

Prior work exploring the role of the cerebellum in cough has been limited to paralyzed preparations. Xu et al. (1997) found in paralyzed, artificially ventilated, and decerebrated cats that after cerebellectomy cough number and expiratory magnitude was reduced with no change in phrenic bursting. However, we hypothesized that the cerebellum would have a different effect on coughing in unparalyzed animals than what was observed by Xu et al. (1997) due to significant behavior‐specific feedback. Cough was induced by mechanical stimulation of the tracheobronchial airways in anesthetized, spontaneously breathing adult cats (n=6). Electromyograms (EMGs) were recorded from upper airway, chest wall and abdominal respiratory muscles. Cough trials were performed before and after a total cerebellectomy. Post cerebellectomy, we observed a decrease in respiratory rate (23±2 to 18±2 breaths/min, p = 0.02) as a result of an increase in the duration of the expiratory phase of breathing (1.5±0.2 to 2.3±0.3 seconds, p = 0.03) and increase in total cycle time (2.7±0.3 to 3.5±0.3 seconds, p = 0.04). Cerebellectomy had no effect on cough number, frequency, esophageal pressure, or bout duration. Post cerebellectomy, there was a significant increase in thoracic inspiratory EMG magnitudes during cough. When normalized to the maximal control effort, on average diaphragm EMG increased from 67±6% to 81±9% (p = 0.04). The left parasternal EMG increased from 70±5% to 98±8% (p = 0.04), and the right parasternal EMG increased from 71± 4% to 93±5% (p = 0.01). The average thyroarytenoid EMG amplitude increased post cerebellectomy (66±6% to 118±26%, p = 0.03), with no change observed in the posterior cricoarytenoid EMG. No significant changes were observed in cough phase durations. Changes in cough EMG magnitudes suggest that the cerebellum modulates cough motor drive, but not cough phase timing or number of behaviors in response to mechanical stimuli in this model. These results suggest an important role of the cerebellum and behavior‐related sensory feedback in the regulation of coughing.Support or Funding InformationSupported by NIH SPARC OT2OD023854‐01 and HL131716.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Evidence for stretch feedback in the thyroarytenoid muscle and potential implications in spasmodic dysphonia
Authors: Reed Mitchell , Huff Alyssa , Iceman Kimberly , Mian Seema , Howland Dena , Pitts Teresa 
Published: June 2021

Muscle position feedback, via receptors for stretch (muscle spindles) and force (golgi tendon organs), is critical for the muscular coordination and proprioception that is essential for most movements. Muscle spindles are innervated by gamma motoneurons that modulate their sensitivity to stretch. Recent reports suggest that 5‐HT1D receptors can modulate gamma motoneurons. Adduction of the vocal folds in the larynx is regulated by the thyroarytenoid muscle, which is active during breathing, cough, swallow, and vocalization. We tested the hypothesis that activation of gamma motoneurons via 5‐HT1D agonists would modulate stretch‐dependent thyroarytenoid activity. Muscle activity (electromyography, EMG) of both the left and right thyroarytenoid muscles was monitored in freely‐breathing sodium pentobarbital anesthetized Sprague Dawley rats. The thyroid and cricoid cartilages were mechanically stretched in an inferior‐superior direction before and after the addition of the 5‐HT1D agonist L‐694,247. Stretching elicited EMG activity from the thyroarytenoid muscle, which increased with the addition of the agonist. Similarly, phasic EMG activity observed during breathing increased with sustained stretching, and further increased with addition of the agonist. These results provide evidence that the previously reported “spindle‐like” structures act in a stretch feedback manner, and modulation of receptors known to exist on gamma motoneurons can amplify this feedback. Identifying and understanding stretch reception in muscles of the larynx may be pivotal to determining the mechanisms of voice disorders including muscle tension dysphonia and spasmodic dysphonia.Support or Funding InformationThis work was supported by NIH grants HL 111215, HL 103415 and OT20D001983, the Craig F. Neilson Foundation Pilot Research Grant 546714, Veterans Affairs Rehabilitation, Research and Development RCSB92495 (DRH), Kentucky Spinal Cord and Head Injury Research Trust, Rebecca F. Hammond Endowment (DRH), and the Commonwealth of Kentucky Challenge for Excellence.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Optogenetic stimulation of the pre‐Bötzinger Complex and the control of breathing in a mouse model of Parkinson's disease
Authors: Santos Luiz Marcelo Oliveira , Baertsch Nathan A , Moreira Thiago Santos , Takakura Ana Carolina , Ramirez Jan‐Marino A 
Published: June 2021

Parkinson's disease (PD) is a neurodegenerative disorder well known for its progressive loss of dopaminergic neurons in the substantia nigra compacta (SNpc). Much less known, yet clinically very important, are the detrimental effects on breathing associated with this disease. Studies in the 6‐hydroxydopamine (6‐OHDA) rat model of PD revealed reductions of respiratory frequency (fR) and NK1r‐immunoreactivity in the pre‐Bötzinger complex (preBötC), a medullary region critical for generating inspiration. To unravel mechanisms that underlie breathing disturbances in PD, we used a transgenic approach to specifically label or stimulate different excitatory (Dbx1‐ERT2Cre, Vglut2‐Cre) and inhibitory (Vgat‐Cre) neural populations in the preBötC. Homozygous Cre mice were bred with homozygous Ai6 (ZsGreen) or Ai32 (ChR2) mice. Adult offspring then received bilateral injections of vehicle or 6‐OHDA (10 μg/μl) into the striatum (CPu) to induce PD; and Ai32 mice also received preBötC fiber optic cannulation. 10–12 days later, whole body plethysmography was used to measure ventilation at rest and during optogenetic photo‐stimulation of the preBötC in unanaesthetized and unrestrained mice. As expected, fR at rest was reduced by 24.9% in PD mice (154.6 ± 6.0 vs. vehicle: 205.9 ± 3.7 bpm, p<0.05). Dbx1 photo‐stimulation during the inspiratory phase did not affect the rhythm in control animals, but increased fR by 17% in PD animals. Similarly, Vglut2 photo‐stimulation in control animals did not change the rhythm, but increased fR by 30% in PD animals. No changes were elicited by photo‐stimulation during expiration. Photo‐stimulation of preBötC inhibitory Vgat neurons during inspiration increased fR by 21%, but only in vehicle‐injected mice; no changes were observed in PD mice. Histology confirmed that 6‐OHDA injections reduced the number of catecholaminergic neurons in the SNpc by 69% (150.4 ± 4.9 vs. vehicle: 494.7 ± 14.5 cells). Surprisingly, the number of Dbx1 and Vglut2 neurons in the preBötC and the adjacent ventral respiratory column (VRC) were also reduced by 47.6 and 17.3%, respectively (p<0.05), whereas the number of Vgat neurons did not change. In conclusion, our study reveals that the 6‐OHDA model of PD is associated with a specific reduction in the number of excitatory neurons within the preBötC, which includes rhythmogenic Dbx1 neurons. Photo‐stimulating specifically these neurons can restore breathing in this PD mouse model.Support or Funding InformationNIH and FAPESP.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.