bluuebunny/crossref_metadata_2025_split huggingface dataset:
FishResp: an R‐package for Filtering and Analyzing Raw Data in Aquatic Respirometry
Authors: Morozov Sergey , McCairns Scott R.J. , Merilä Juha 
Published: November 2023

One of the most common approaches for measuring metabolic rate of aquatic animals is whole‐body respirometry. Respirometry systems that are currently available on the market allow researchers to get raw respirometry data of high accuracy. However, further data processing, including quality‐control tests, is left to researchers' discretion. There is currently no universal tool for filtering raw data and extraction of key parameters from the massive datasets consisting point observations. This methodological disunity affects further comparability of research findings, and published studies contain contradictory estimations of metabolic rates in different fish species. For example, background respiration of microorganisms present inside chambers and tubing is one of the most significant factors that influence the quality and reliability of raw respirometry data. Different methodologies are known to correct for microbial oxygen consumption, but a lack of such correction appears to be common in many published studies. The problem is especially relevant when respirometry measurements are performed in conditions favorable for microbial growth, e.g. at high water temperatures. Consequently, without proper quality controls and data filtering, oxygen consumption in aquatic animals may be significantly overestimated.To overcome problems associated with raw respirometry data processing, we have developed an R‐package ‘FishResp’. This package is freely available, versatile and easy‐to‐use. Being compatible with raw data from various commercial respirometry systems, it allows users to perform quality control checks for chamber leaking and microbial oxygen consumption. We demonstrate the virtues of FishResp and its applicability in correcting for background respiration, using raw data obtained from metabolic rate measurements of the Trinidadian guppy (Poecilia reticulata). This example is peculiar as the species' reported mean standard metabolic rate measured at 25–26°C temperature varies substantially in different studies (100–500 mgO2/kg/h). Using FishResp software, we show that background respiration in chambers may make up to 75% of the total oxygen consumption during a long‐term experiment with a regular cleaning protocol.We wish to promote FishResp as a common tool for raw data processing in metabolic rate estimation in aquatic animals. A user‐friendly GUI version and a simple user manual are under development and will be available at the official website fishresp.org in 2017.Support or Funding InformationSM: LUOVA doctoral programme, Alfred Kordelin Foundation, Oskar Öflund Foundation; RJSM, JM: Academy of Finland
Expression of skeletal muscle miRNA are unaltered during 14 days of bed rest but decrease following 7 days of reloading in middle‐aged adults
Authors: Arentson‐Lantz Emily J , Lamon Séverine , Fry Christopher S , English Kirk L , Paddon‐Jones Doug 
Published: November 2023

microRNA (miRNA) play an important role in mitigating expression of molecular pathways that govern skeletal muscle health. Bed rest accelerates the loss of muscle mass and function; however, little is known about the role that miRNA play in muscle health during inactivity and subsequent recovery. We examined the effect of 14 days of bed rest and 7 days of rehabilitation on miRNA expression, muscle atrophy and function in middle‐aged adults. Muscle biopsies were obtained from the vastus lateralis of healthy middle‐aged (average age 51.7±1 y) male and female adults (n=19) before (PreBR) and after (PostBR) 14 days of bed rest and after (Rehab) 7 days of rehabilitation for miRNA and immunohistochemical analysis. Body composition, muscle strength and aerobic capacity were assessed using iDEXA, dynamometry, and VO‐2‐ max testing, respectively. Collective miRNA expression was screened using Firefly Bioworks multiplex assay with a custom panel of 65 candidate species. Based on prelimnary statistical analysis of multiplex assay, individual miRNA expression was confirmed using miRNA‐specific stem‐loop primers (TaqMan® microRNA assay kit) and qPCR. Expression of miR206 (1.07, 1.22, and 0.94 ± 0.16 for PreBR, PostBR, and Rehab), mir133a (1.10, 1.18, and 0.95 ± 0.05 for PreBR, PostBR, and Rehab), mir378 (1.46, 1.47, and 1.20 ± 0.05 for PreBR, PostBR, and Rehab) and let7b (0.89, 0.97 and 0.87 ± 0.05 for PreBR, PostBR, and Rehab) did not change with bed rest, but were significantly decreased following 7 days of rehabilitation. Muscle quality, relative VO2 max (ml/min/kg), fiber cross sectional area and satellite cell number decreased during bed rest and did not return to baseline values. The precise role of miRNAs in muscle regrowth is not well understood. However, the overall pattern of response of miRNAs 206, 133a, 378 and let7‐b to rehabilitation indicate they may involved in the coordinated process to restore muscle mass and function following disuse.Support or Funding InformationThis research was supported by: NSBRI‐NNJ08ZSA002N, RO1 NR012973, P30 AG024832.
miRNA‐Mediated Regulation of Insulin Sensitivity in Skeletal Muscle Cells
Authors: Petrocelli Jonathan , Beach Cassandra , Marino Joseph S. 
Published: November 2023

BackgroundMicro RNAs (miRNAs) are a class of small non‐protein coding RNAs that bind specific 3′‐untranslated regions of messenger RNAs (mRNAs), inhibiting the translation of mRNA to functional protein. Which miRNAs are important for skeletal muscle health and how they regulate metabolic and functional plasticity is poorly understood. Recent evidence from studies in hepatocytes suggests that miR26a regulates insulin sensitivity.PurposeThe purpose of this study was to determine whether miR26a regulates insulin sensitivity in skeletal muscle cells.MethodsC2C12 mouse myoblasts were induced to differentiate into myotubes for 4 days. Cells were serum starved for 2 hours followed by treatment with palmitate (.75mM) or vehicle for 2 hours. Cells were then treated with insulin (10nM) for 20 minutes. Real‐time PCR was used to investigate changes in miRNA expression.ResultsIn silico mapping of miR26a target mRNA revealed high complementarity for the protein kinase C theta (PKCθ) transcript. PKCθ is a lipid sensitive kinase associated with skeletal muscle insulin resistance. Upon treatment with palmitate, miR26a expression decreased by approximately 75%, corresponding to an increase in PKCθ.ConclusionsThese data suggest that PKCθ and miR26a may exist in a regulatory pathway that alters insulin sensitivity in the presences of saturated fatty acid. Work is ongoing to more comprehensively investigate the mechanistic connection between miR26a and PKCθ in the regulation of fatty acid‐induced insulin resistance in skeletal muscle cells.
Reducing Allergic Asthma Inflammation and Airway Hyperresponsiveness via a Novel Protease‐Activated Receptor‐2 Antagonist
Authors: Rivas Candy M. , Lovett Marissa K. , Neenan Tyler , Yee Michael , DeFea Kathryn A , Daines Michael , Vagner Josef , Boitano Scott A. 
Published: November 2023

Protease‐activated receptor‐2 (PAR2) belongs to a family of four G protein‐coupled receptors that possess the unique ability to self‐activate upon proteolysis of the extracellular amino terminus. The resulting exposure of the activating peptide sequence or tethered ligand leads to receptor activation and stimulation of both β‐arrestin‐ and Gαq‐dependent signaling. Studies examining the link between PAR2 and inflammation delineate a central role for PAR2‐dependent β‐arrestin signaling in the epithelial initiation of airway inflammation present in asthma development. The current model suggests PAR2 expressed by the airway epithelium is at a prime location to encounter proteases in asthma‐causing environmental allergens and subsequent PAR2 activation and signaling is the initiator of airway inflammation. Recently, our lab has developed C391, a potent PAR2 antagonist that has shown to be effective in blocking peptidomimetic‐ and protease‐containing asthma‐associated allergen (Alternaria alternata)‐induced PAR2 signaling both in vitro and in vivo. In an In Cell Western assay, micromolar concentrations of C391 were found to effectively inhibit 2at‐LIGRLO‐ and A. alternata‐induced MAPK activation. Fluorescent calcium imaging showed that C391 was effective at preventing 2at‐LIGRLO‐induced Ca2+ responses in bronchial epithelial cells with a half maximal inhibitory concentration of 1.3μM, while preliminary data indicate C391 also blocks A. alternata‐induced Ca2+ responses. Results from a time‐resolved fluorescence competitive binding assay show C391 inhibits PAR2 binding of 2f‐LIGRL‐dtpa with an apparent IC50 = 8.55pM. Data from these molecular and cellular techniques provide proof of potent PAR2 inhibition by C391. To understand the effects of PAR2 inhibition in vivo, C391 was applied to murine asthma models. In vivo data shows that C391 attenuates the development of airway hyperresponsiveness in A. alternata‐sensitized mice and analysis of bronchoalveolar lavage fluid shows reduced inflammatory cell recruitment to the lungs. Thus, in vitro data provides evidence that C391 effectively inhibits PAR2 signaling, while in vivo data demonstrates PAR2 antagonism may confer physiological benefit via mitigation of airway inflammation and pathological airflow limitation. Taken together, this data demonstrates the utility of our novel antagonist, C391 in studying the capacity of PAR2 modulation in asthma development and supports the validity of our molecular target, PAR2 in the development of novel, improved therapies for allergic asthma.Support or Funding InformationThis work was funded by National Institutes of Health grants NS 073664 and R01 A1083403 and support provided through the William Townsend Porter Pre‐doctoral Fellowship awarded by the American Physiological Society.
Role of PGE2‐EP1/EP3 receptor signaling on hyperoxia‐induced airway hyperreactivity in neonatal rats
Authors: Thaçi Qëndrim , Cenaj Asllan , Sopi Ramadan B 
Published: November 2023

Hyperoxic exposure of neonates is followed by airway hyperreactivity, that involves many different molecular signaling mechanisms, including PGE2/EP‐receptor signaling. The aim of this study was to investigate the role of EP1/EP3 receptors on airway hyperreactivity in neonatal rats exposed to hyperoxia. Tracheal cylinders were obtained from Wistar rat pups (P12) exposed for seven days to hyperoxia or room air. The preparations were used to study contractile responses in an in vitro organ bath system. In hyperoxic group the contractile responses significantly were enhanced towards a muscarinic agonist (methacholine) as compared to room air control group. Pre‐incubation of tissues on EP1/EP3 antagonists, significantly reduced these enhanced responses in hyperoxic group. Use of EP1/EP3 agonists and Rho‐kinase inhibitors disclosed the involvement of Rho‐kinase pathway on the signaling of EP1/EP3 receptors. The results of this study for the first time confirm the contribution of the EP1/EP3 receptors on hyperoxia‐induced airway hyperreactivity and the involvement of Rho‐kinase pathway. We suggest the use of EP1or EP3 antagonists or Rho‐kinase inhibitors as a therapy parallel to hyperoxic exposure in order to overcome the adverse effects of neonatal hyperoxia and to prevent the development of bronchopulmonary dysplasia as consequence of hyperoxic exposure.Support or Funding InformationSupported by MEST
Regulation of endogenous Kv7 potassium channels by histamine in primary cultured human airway smooth muscle cells.
Authors: Haick Jennifer M. , Brueggemann Lyubov I. , Schwartz Jeffrey L. , Byron Kenneth L. 
Published: November 2023

Kv7 potassium channels were recently found to be expressed in airway smooth muscle cells (ASMCs) of different species including humans. Previous research studies on guinea pigs and rats suggests that native Kv7 currents are inhibited following treatment of ASMCs with bronchoconstrictor agonists; in intact airways this inhibition is sufficient to stimulate L‐type Ca2+ channels in ASMCs, resulting in ASMC contraction and bronchiolar constriction. Although KCNQ genes which encode for Kv7 channels are expressed in human tracheal smooth muscle, no human ASMC culture model has been developed to investigate the regulation of native Kv7 currents or its role in Ca2+ signaling. Here we found that bronchoconstrictor agonist histamine (1 μM) induced Ca2+ influx in monolayers of primary cultured human ASMCs. This Ca2+ influx was prevented by application of L‐type Ca2+ channel blocker verapamil (10 μM). Perforated‐patch clamp electrophysiology was employed to detect endogenous Kv7 currents in primary cultured human ASMCs. Small endogenous Kv7 currents sensitive to Kv7.2–7.5 activator retigabine (10 μM) were detected in 60% of ASMCs. After washout of retigabine, Kv7 currents returned to the control level and were inhibited by subsequent application of histamine (10 μM, 43 ± 11% inhibition at −20 mV, n=6). Histamine induced inhibition of endogenous human Kv7 currents in ASMCs was completely reversed by addition of histamine H1 receptor antagonist chlorpheniramine (100 μM). Pan Kv7 channel blocker XE991 (10 μM) applied at the end of each experiment inhibited 84 ± 8% of the current at −20 mV. The present study provides new evidence for a role of Kv7 channels in bronchoconstrictor Ca2+ signaling in cultured human ASMCs.Support or Funding InformationThe project described was supported by Award Number I01BX007080 from the Biomedical Laboratory Research & Development Service of the VA Office of Research and Development.
Quercetin Reverses the Enhanced Contractile Responses of Tracheal Smooth Muscle of Neonatal Rats Exposed to Hyperoxia
Authors: Kryeziu Islam , Thaçi Qëndrim , Reçica Shkëlzen , Kurshumliu Fisnik , Vela Driton , Mladenov Mitko , Basholli Mimoza , Sopi Ramadan B 
Published: November 2023

Neonatal hyperoxia increases contraction and decreases the relaxation of airway smooth muscle (ASM), and the balance between these processes in airways is critical for normal flow of air. Thus, it is important to search for an effective treatment to prevent the airway hyperreactivity. Therefore, we tested the hypothesis that supplementation of quercetin will overcome the enchanced contractile responses of tracheal smooth muscle exposed to hyperoxia. Tracheal cylinders were obtained from Wistar rat pups (P12) exposed to hyperoxia (≥ 95% O2) or room air for seven days. These cylinders were used to study contractile responses of ASM evoked by methacholine (MCh, 10‐8 – 10‐4 M) in absence or presence of quercetin (100 μM). MCh induced dose‐dependent contractile responses of ASM. Hyperoxic exposure significantly increased the contractile responses of ASM towards MCh, as compared to those obtained from control animals exposed to room air, and these enhanced contractile responses in hyperoxic tissues were significantly attenuated in presence of quercetin. The results of this study revealed that quercetin reverses the enhanced contractile responses of airway smooth muscle induced by hyperoxic exposure and we speculate that the use of quercetin might be an effective therapeutic approach to prevent the airway hyperreactivity induced by hyperoxia.Support or Funding InformationSupported by MEST
Divergent Effects of Myo‐inositol Supplementation on Respiratory Control During Postnatal Development
Authors: MacFarlane Peter , Di Fiore Juliann , Mayer Catherine 
Published: November 2023

Myo‐inositol is a nutritional supplement and a naturally occurring sugar derived from the breakdown of glucose – it can ultimately form important structural lipids and intracellular second messengers. Myo‐inositol is found in breast milk and serum levels decrease naturally in the newborn over the first postnatal weeks. Prior studies have demonstrated beneficial effects of myo‐inositol supplementation on lung development in preterm infants. In the current study, we tested the hypothesis that myo‐inositol administration during the postnatal period would affect respiratory control in neonatal rats. Rat pups received sub‐cutaneous injections of myo‐inositol (80mg/kg/day) for the first 2 postnatal weeks and the ventilatory responses to acute (5 min) hypoxia (HVR; 10% O2) or hypercapnia (HCVR; 5% CO2) were assessed at 1 or 2 weeks of age. In 1 week old rats, myo‐inositol abolished (−7.6 ± 9.4% change from baseline) the acute HVR compared to vehicle (26.6 ± 11.8% change from baseline) treated pups In contrast, myo‐inositol had the opposite effect at 2 wks of age and enhanced the acute HVR (73.4 ± 11.5% change from baseline) compared to age‐matched vehicle (saline; 41.6 ± 11.9% change from baseline) treated rats. Myo‐inositol did not affect the acute HCVR in either age group suggesting its effects (at each age group) are unique to the hypoxic sensitive pathways. Neither body weight or baseline ventilation were affected by myo‐inositol in any age group. These data demonstrate a divergent effect of myo‐inositol treatment on respiratory control during postnatal development, characterized as an inhibitory effect on the HVR at 1 wk, followed by a rapid (days) transition to an augmenting effect by 2 weeks of age. Such contrasting effects of myo‐inositol reveal potentially deleterious vs beneficial effects on respiratory neural control during specific stages of postnatal development. These data may have implications for the way that postnatal changes in dietary myo‐inositol could influence the severity of respiratory morbidities associated with abnormal respiratory control that are common to preterm infants including respiratory distress and apnea of prematurity.Support or Funding InformationThe Gerber Foundation
The Metaboreflex and the Peripheral Chemoreflex Interact for the Regulation of Ventilation in Patients with Chronic Heart Failure
Authors: Machado Alessandro Costa , Vianna Lauro Casqueiro , Gomes Erika Alvarenga Correa , Teixeira Jose Antonio Caldas , Ribeiro Mario Luiz , Junior Humberto Villacorta , Nobrega Antonio Claudio Lucas , Silva Bruno Moreira 
Published: November 2023

Patients with chronic heart failure (CHF) tipically present exacerbated ventilation (VE) response to exercise. This phenomenon is associated with exercise intolerance and worse prognosis, and seems to be mediated, at least in part, by abnormalities in the neural control of VE, such as enhanced VE response to activation of muscle afferents sensitive to metabolites (i.e., enhanced metaboreflex), as well as enhanced VE response to inhalation of hypoxic air at rest (i.e., enhanced peripheral chemoreflex). However, the interaction between these reflexes remains unknown in CHF. Then, we sought to test the hypothesis that the activation of the metaboreflex could enhance the contribution of the peripheral chemoreflex for the regulation of VE in patients with CHF. Six men with CHF under optimal pharmacological treatment (New York Heart Association class II‐III, mean ± SD age of 55 ± 6 years and left ventricular ejection fraction (Simpson) 33.7 ± 2.9%) were submitted to 4 steady‐state cycling sessions at 60% of maximal power output for 4 minutes. Then, they recovered for 2 minutes under either 1) post exercise ischemia (PEI) plus normoxia (21% O2), 2) PEI plus hyperoxia (100% O2), 3) free flow plus normoxia, or 4) free flow plus hyperoxia. PEI was used to trap metabolites in the lower limbs, and, consequently, activate the metaboreflex, while hyperoxia was used to inhibit the peripheral chemoreceptors. Patients were blinded to the O2 concentration in the inhaled air. A rebreathing circuit was used during recovery to match the end tidal partial pressure of CO2 (PetCO2) among conditions. Breath‐by‐breath data recorded at peak and throughout recovery were averaged in 20‐s windows for statistical analyses. Peak VE was similar among conditions. As expected, end tidal partial pressure of O2 was higher during hyperoxia than normoxia throughout the recovery period. VE decayed during recovery in all conditions. Of note, hyperoxia augmented the VE decay versus normoxia at 21–40 s (hyperoxia: 16.7 ± 2.3 L/min vs. normoxia: 22.7 ± 2.9 L/min, P < 0.001) and 41–60 s (hyperoxia: 17.1 ± 1.5 L/min vs. normoxia: 20.5 ± 2.2 L/min, P = 0.01) of recovery during PEI. However, hyperoxia did not change VE decay versus normoxia during free flow recovery. Collectively, our findings indicate that the activation of the metaboreflex enhances the peripheral chemoreflex regulation of VE in patients with CHF, which confirms the interaction between these reflexes. This interaction may, consequently, mediate part of the exaggerated VE response to exercise, which is a hallmark of patients with CHF.Support or Funding InformationSão Paulo Research Foundation (FAPESP), National Counsel of Technological and Scientific Development (CNPq), and Research Support Foundation of the State of Rio de Janeiro (FAPERJ).
Triple Oscillator Hypothesis: Three Excitatory Rhythm Generating Networks Control the Three Phases of Breathing
Authors: Anderson Tatiana M. , Garcia Alfredo J. , Baertsch Nathan A. , Pollak Julia , Ramirez Jan‐Marino 
Published: November 2023

Breathing is composed of three phases: inspiration, postinspiration, and active expiration. Excitatory rhythm generating networks have been identified for the generation of inspiration, the preBötzinger complex (preBötC), and for active expiration, the lateral parafacial (pFL). By utilizing a combination of a new in vitro horizontal slice preparation, optogenetics, and in vivo techniques, we have recently identified and characterized a novel population of neurons that we show to be necessary and sufficient for the generation of postinspiration (Anderson et al. 2016). This network, located dorsomedial to the nucleus ambiguus and caudal to the facial nucleus, is referred to as the postinspiratory complex, or PiCo. PiCo can function as an independent oscillator dependent on excitatory, non‐NMDA mechanisms. Here we show that a subpopulation of PiCo neurons are endowed with ICAN and INaP dependent pacemaker properties, suggesting that PiCo has similar rhythm generating properties to the preBötC. Additionally, we observed differential effects of inhibitory antagonists. When strychnine, a glycine receptor antagonist, was bath applied to the horizontal slice in vitro, the burst duration of fictive inspiratory preBötC bursts significantly decreased while PiCo burst duration was unchanged. Upon the additional application of gabazine, a GABAergic receptor antagonist, the two rhythms progressively synchronized. Furthermore, in the presence of gabazine, the average burst area and amplitude significantly increased for both preBötC and PiCo rhythms. Based on our discovery, we propose a triple‐oscillator hypothesis that states that the three phases of respiration are generated by three, anatomically distinct, excitatory, rhythmogenic and interactive networks: the preBötC, PiCo, and PFL. We further conclude that network inhibition serves to coordinate the timing, phasing and patterning of these rhythms.Support or Funding Information1F31NS087828‐01RO1 HL107084‐01