bluuebunny/crossref_metadata_2025_split huggingface dataset:
Acute Sildenafil Treatment Improves Exercise Capacity in Patients with Cystic Fibrosis
Authors: Gonzalez Vincent , Siegler Nichole , Crandall Reva , Mckie Kathleen T. , Forseen Caralee , Rodriguez‐Miguelez Paula , Tucker Matthew , Harris Ryan A. 
Published: June 2021

BackgroundExercise capacity has been shown to predict quality of life, mortality, and risk for hospitalization in patients with Cystic Fibrosis (CF). Many patients with CF exhibit exercise intolerance, the mechanism of which has yet to be elucidated. Sildenafil, a phosphodiesterase type 5 inhibitor, increases blood flow and therefore may improve exercise capacity in patients with CF.PurposeThe purpose of this study was to determine whether an acute dose of sildenafil improves exercise capacity in patients with CF.Methods13 patients with CF (mean age = 25 ± 10 years) participated in a double blind, randomized, placebo controlled study. Exercise capacity utilizing the Godfrey Protocol on a cycle ergometer was assessed at baseline and 1 hour following treatment with either sildenafil (50 mg) or placebo.ResultsA significantly greater increase (p = 0.024) in VO2 peak was observed following sildenafil treatment (4.16 ± 1.54 ml/kg/FFM) compared to placebo (1.09 ± 1.31 ml/kg/FFM). The change in maximal heart rate during exercise was statistically (p = 0.007) greater following sildenafil treatment (6.07 ± 4.04 bpm) compared to placebo (−1.54 ± 6.06 bpm). The change in chronotropic index (CRI) was significantly (p = 0.006) higher following sildenafil treatment (0.08 ± 0.02) compared with placebo (0.04 ± 0.02).Conclusion/InterpretationThese findings suggest that an acute dose of sildenafil improves exercise capacity in patients with CF. In addition, treatment with sildenafil improved CRI. Future studies should focus on elucidating the mechanisms for improvement in exercise capacity and CRI as both are predictors of mortality.Support or Funding InformationSupported in part by the Medical College of Georgia's Medical Scholar Program and the Laboratory of Integrative Vascular and Exercise Physiology.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Low‐load Resistance Exercise with Blood Flow Restriction Changes Hypoxia‐Induced Genes Expression
Authors: Laurentino Gilberto , Aoki Marcelo , Fernandes Rodrigo , Soares Antonio , Ugrinowitsch Carlos , Hoschel Hamilton , Tricoli Valmor 
Published: June 2021

PURPOSETo investigate the effects of low‐load exercise with blood flow restriction on expression of genes related to hypoxia.METHODSTwenty‐four male (mean ± SD: age 21.3 ± 1.9 years, height 1.74 ± 0.8 m, body mass 73 ± 1.8 kg) were divided into three groups: low‐load exercise (LL, n=9), low‐load exercise with blood flow restriction (LL‐BFR, n=8), and high‐load exercise (HL, n=7). For LL‐BFR group a pneumatic cuff was placed on the proximal portion of the thigh and inflated at 80% of the resting arterial occlusion pressure. All subjects performed bilateral knee extension, 2x/week, during 8 weeks. LL and LL‐BFR groups performed 3–4 sets of 15 reps at 20% 1RM whereas HL performed 3–4 sets of 8–10 reps at 80% 1RM with 60s rest interval between sets. Regulated in development and DNA damage response 1 (REDD1), hypoxia‐inducible factor‐1‐alpha (HIF‐1‐alpha), vascular endothelial growth factor (VEGF), and neuronal nitric oxide synthase (nNOS) mRNA gene expression were assessed before and after training. Mixed model for repeated measures was performed for each dependent variable, and statistical significance was set at p≤ 0.05.RESULTSREDD1 expression decreased in all groups from pre‐ to post‐training (p<.0001), and significantly lower REDD1 expression was found in both LL‐BFR and HL groups when compared with LL group at post‐training (p<0.05) [Figure 1A). HIF‐1α mRNA expression increased in all groups from pre‐ to post‐training (p<.0001), and significantly greater values were observed in LL‐BFR and HL groups when compared with LL group at post‐training (p<.0001) [Figure 1B]. VEGF mRNA expression increased in both LL‐BFR and HL groups from pre‐ to post‐training (p<.0001); however, only LL‐BFR showed greater expression than LL group at post‐training (p=0.001) [Figure 1C). nNOS mRNA expression increased in all groups from preto post‐training (p<.0001), and greater expression values were observed in LL‐BFR when compared with both LL and HL groups at post‐training (p<.0001) [Figure 1D].CONCLUSIONLow‐load resistance exercise with blood flow restriction induced changes in selected genes expression related to hypoxia following training. These results may contribute with the skeletal muscle hypertrophy responses and increased muscular angiogenesis after training period.Support or Funding InformationThis study was not supported by any fundingThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Autophagy promotes cancer chemotherapy‐induced oxidative stress and skeletal muscle dysfunction
Authors: Smuder Ashley J. , Kwon Oh Sung , Hain Brian A. , Houston Fraser E. , Talbert Erin E. 
Published: June 2021

Chemotherapy‐induced cachexia is a debilitating condition characterized by fatigue and muscle wasting. The onset of muscle weakness in patients often limits treatment, resulting in reduced quality of life and increased morbidity. Our previous findings show that the chemotherapeutic agent doxorubicin (DOX) causes myotoxicity as a result of reactive oxygen species (ROS) generation during intracellular metabolism of DOX by the mitochondria, and subsequent activation of the autophagy/lysosomal system. We hypothesize that DOX‐induced accelerated autophagy results in the elimination of vital cellular organelles and proteins, resulting in functional deficits to the muscle tissue. To prevent elevated activity of the autophagy/lysosomal system, we administered a dominant negative mutation of the autophagy protein ATG5 (rAAV‐dnATG5) via intramuscular injection of the rat soleus muscle four weeks prior to treatment. Animals received either DOX (20 mg/kg ip) or saline. Two days after chemotherapy, soleus muscle specific force production and fiber cross‐sectional area were significantly reduced in control animals. These changes corresponded with deficits to mitochondrial respiration, increased mitochondrial ROS emission and the increased appearance of autophagic vacuoles within the muscle. In contrast, rAAV‐dnATG5 administration in DOX treated animals prevented the conjugation of ATG12 and ATG5 thereby reducing autophagosome formation within the soleus muscle. Interestingly, the protein expression of catalase and superoxide dismutase 2 (SOD2) was elevated in these animals, which may account for improved mitochondrial respiration and reduced mitochondrial free radical production. Finally, DOX‐induced muscle fiber atrophy and contractile dysfunction were prevented in rAAV‐dnATG5 animals. These findings indicate that accelerated autophagy is an underlying cause of chemotherapy‐induced oxidative damage and skeletal muscle weakness.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Identification and Characterization of Mago Homology B (Magohb) in Skeletal Muscle
Authors: Zubair Samira , Waddell David 
Published: June 2021

Skeletal muscle atrophy is a physiological condition that occurs due to immobilization, denervation, spinal cord transection and aging. Muscle wasting causes significant loss of muscle size, a measurable reduction is strength, and decreased mobility. In order to better characterize the molecular genetic events of neurogenic atrophy, the gastrocnemius muscle was isolated from mice following 3 days and 14 days of sciatic nerve denervation. The gene expression profile in the denervated muscle tissue was then analyzed by microarray and compared to control muscle tissue in order to identify novel neurogenic atrophy‐induced genes. The microarray data revealed for the first time that Mago Homology B (Magohb), an exon junction core complex component involved in splicing and mRNA surveillance, is expressed in skeletal muscle and is significantly induced in response to denervation. To confirm that Magohb is expressed in muscle cells, quantitative PCR (qPCR) was used to assess Magohb expression levels in both proliferating and differentiated muscle cells and the results demonstrate that Magohb is expressed in both proliferating myoblasts and differentiated myotubes. In order to characterize the transcriptional regulation of Magohb, fragments of the proximal promoter located immediately upstream from the start of transcription were cloned and fused to a reporter gene. The reporter plasmids were then transfected into C2C12 mouse muscle cells alone or in combination with myogenic regulatory factor expression plasmids, resulting in a differential effect on reporter activity. Furthermore, bioinformatic analysis of the promoter region of Magohb revealed a conserved canonical E‐box element, which is a known myogenic regulatory factor (MRF) binding site, further suggesting that Magohb may be regulated by muscle specific transcription factors. Finally, since Magohb is believed to play a role in exon‐exon junction identification and may play a role in mRNA splicing, we fused Magohb to GFP, transfected mouse myoblasts with the Magohb‐GFP expression plasmid, imaged the cells using confocal microscopy, and confirmed that Magohb is predominately localized to the nucleus. The discovery that Magohb is expressed in skeletal muscle combined with the observation that this gene, a potential modulator of mRNA processing, is induced in response to neurogenic atrophy helps further our understanding of the molecular genetic events of skeletal muscle wasting.Support or Funding InformationThe work was support by University of North Florida Transformational Learning Opportunity grants to D.W.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Characterization of the Regulation and Function of Tetratricopeptide 39c (Ttc39c) in Skeletal Muscle
Authors: Hayes Caleb , Waddell David 
Published: June 2021

Ttc39c has been identified as a novel gene in skeletal muscle that is differentially regulated in response to neurogenic atrophy in wild‐type (WT) mice compared to Muscle RING Finger 1 (MuRF1) knockout (KO) mice. MuRF1 is a ubiquitin E3 ligase that is known to be an important mediator of muscle wasting; however, more recent research suggests that MuRF1 may also function as a regulator of atrophy‐induced gene expression. Quantitative PCR and Western blot analysis determined that Ttc39c is expressed in both proliferating and differentiated muscle cells. Furthermore, comparison of Ttc39c expression in undifferentiated and differentiated C2C12 cells demonstrated that Ttc39c levels are elevated in proliferating myoblasts, but decrease in differentiated myotubes. The transcriptional regulation of two Ttc39c isoforms with alternative transcriptional start sites were examined by cloning the unique promoter regions of each transcript. The Ttc39c reporter gene constructs were transfected into muscle cells and confirmed to have significant transcriptional activity in cultured muscle cells and are transcriptionally responsive to ectopic expression of myogenic regulatory factors (MRF). Furthermore, conserved E‐box elements in the proximal promoter regions of both Ttc39c transcripts were identified, mutated, and analyzed for their role in the transcriptional regulation of Ttc39c expression. The mutation of the conserved E‐box sequences rendered the Ttc39c reporter genes inactive, suggesting that these elements are potentially necessary for Ttc39c expression. Finally, immunoprecipitation (IP) of Ttc39c from C2C12 cells resulted in the co‐IP of numerous binding partners, which are currently being identified by proteomic analysis in the hope of elucidating a potential function for Ttc39c in skeletal muscle based on identified binding partners. Interestingly, ectopic expression of Ttc39c in C2C12 mouse myoblasts resulted in delayed cell fusion and reduction in myotube formation. The identification and characterization of novel genes that are activated during neurogenic atrophy helps improve our understanding of the molecular genetic events that result in muscle wasting and could eventually lead to new therapeutic targets in the future.Support or Funding InformationThe work was support by University of North Florida Transformational Learning Opportunity grants to D.W.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Effects of Estrogen on Statin‐Induced Myotoxicity in Vitro
Authors: Roussel Jaclyn , Stambersky Ashten , Ball Karen L. 
Published: June 2021

In vitro studies have suggested a greater statin‐induced myotoxicity in females. This is in contrast to what would be predicted based on estrogen (E) protection against other models of muscle damage. Therefore, the purpose of this study was to examine estrogen effects in an in vitro model of statin‐induced myotoxicity. C2C12 myoblasts were plated at a density of 0.15×105 cells in a 6‐well plate and maintained in growth media (GM) until 80%–100% confluence. Media was then replaced with differentiation media (DM) and cells allowed to differentiate for seven days. Differentiated cells were then exposed to Simvastatin (SS;10−4 mM), E alone (0.1 μM or 0.01 μM), or SS+E. After 48 hours, light microscopic images were taken to measure multinucleated cell numbers and fiber diameters. At 72 hours, immunofluorescence was performed to identify myosin positive cells and apoptotic nuclei. The SS induced toxicity was consistent with previous studies. Fiber diameters were decreased (45.7±4.1 μm vs 16.0±1.8 μm*) with significant increase in apoptotic nuclei (17%±1.4% vs 55.3%±4.3%*). Interestingly, the effects of E in combination with SS were dependent on the parameters measured. Whereas E produced a protective trend with greater fiber diameters (23.7±5.4 μm vs 16.0±1.8 μm;NS), E exacerbated the SS impact on apoptosis (74%±6.4%–87%±8.1% vs 55.3%±4.3%*). In conclusion, our data revealed contradictory influences of E on statin‐induced myotoxicity. Clarification of estrogen's effect could have significance in understanding gender specific adverse clinical responses to stain therapy. *p<0.05Support or Funding InformationThe Herbert H. and Grace A. Dow FoundationThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Genetically Engineering a Sheep Model of Hypophosphatasia
Authors: Williams Diarra Kevin , Pinzon Carlos A. , Huggins Shannon , Pryor Jane H. , Georges Hanah M. , Hermann Forrest , Oldeschulte James , Westhusin Mark E. , Long Charles R. , Gaddy Dana , Suva Larry J. 
Published: June 2021

Hypophosphatasia (HPP) is a rare inherited disorder that affects the development of bones and teeth. The disease is caused by mutations in the tissue‐nonspecific alkaline phosphatase (TNSALP) gene (ALPL) and accompanied by a highly variable clinical presentation. Although HPP patient studies have advanced our understanding of HPP, as well as documented disease severity, the rarity of the disease combined with a lack of sufficient animal models has significantly delayed mechanistic understanding and therapeutic development. Similar to other human disease models, current HPP models have been engineered virtually exclusively in rodents – specifically mice harboring null or loss‐of‐function mutations. Although useful for modeling some features of HPP, these murine models do not faithfully represent the broad spectrum of human HPP clinical bone, muscle and tooth (odonto‐HPP) phenotypes. However, in sheep both Haversian bone remodeling and tooth development are analogous to humans with sheep TNSALP amino acid sequence sharing 89% identity with human. Thus, our objective was to generate a sheep model of HPP and we posit that ALPL mutation‐specific replacements in the sheep genome using CRISPR/Cas9 will produce a model that accurately phenocopies the bone and tooth pathophysiology of HPP. To genetically engineer a sheep model of HPP, a total of 52 in vitro genetically manipulated embryos were generated targeting the Exon 10 c.1077G>A mutation using CRISPR/Cas9. Three embryos were implanted per recipient ewe and implantations were performed in a total of 17 recipient ewes. Nine ewe pregnancies were confirmed by the measurement of Pregnancy‐Associated Protein on post‐implantation day 35 and further validated by ultrasound. From 9 live newborn lambs, four were heterozygous for our specific point mutation (4/6), one compound heterozygous (1/6) and one homozygous (1/6) for a total mutation efficiency rate of 66.6% (6/9). Similar to HPP patients with the same mutation, mutant sheep have variable clinical expression accompanied with decreased bone formation and mineralization in tails observed by DXA as well as significantly and appropriately decreased serum alkaline phosphatase activity. Additionally, an apparent “shell tooth” phenotype is observed in mutant lambs, further suggesting a mutant exon 10 genotype/phenotype that more completely recapitulates human skeletal and odonto‐HPP.Support or Funding Information1. William Townsend Porter Pre‐doctoral Fellowship2. TAMU/Texas Heart Institute Center for Cell and Organ Biotechnology Innovation Kitchen GrantThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
The Status Of Protein Translation In A Metabolically Flexible Mammal, The Common Tenrec, Tenrec ecaudatus
Authors: Wilson Jared Nicholas , van Breukelen Frank 
Published: June 2021

Common tenrecs, Tenrec ecaudatus, are small tropical hibernating mammals endemic to Madagascar. Tenrecs possess many phenotypic features associated to ancestral mammals, suggesting they may act as a model of an ancestral form of hibernation. Common tenrecs are able to hibernate at ambient temperatures ranging from 12 to 28 °C and do not undergo brief periodic returns to euthermy during the hibernation season, a shared feature among all other known hibernators. Tenrecs display extreme metabolic flexibility. For instance, they can spontaneously enter torpor during the active season, termed facultative torpor (FT). During both hibernation and FT, oxygen consumption rates have been observed to be 1–14% of active rates depending on ambient temperatures. Protein metabolism may account for 30% or more of standard oxygen consumption rates for most animals. Polysome profiles were used to determine the status of translation in tenrecs as a function of core body temperature (Tb) and activity state. Our findings will provide mechanistic data that will be used to elucidate how common tenrecs are able to regulate metabolic flux exclusive of Tb.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Friend or Family? Social Recognition and Physiological Stress in the Self‐Fertilizing Mangrove Rivulus Fish (Kryptolebias marmoratus)
Authors: Trueman Justin D. , Currie Suzie 
Published: June 2021

Social behavior has the capacity to influence how animals respond to environmental stress. Living in social groups may be beneficial to animals as it can reduce predation risk and provide foraging benefits. Advantages may be further enhanced if animals associate with related individuals (kin), with individuals of the same phenotype and/or with familiar conspecifics, regardless of relatedness. On the other hand, grouping may incur costs if there is competition for resources or increased aggression. Given the potential influence of sociality on physiological responses to stress, it is important to understand an animal's social behavior and if certain social interactions result in physiological stress. The mangrove rivulus is a tropical, self‐fertilizing fish that forms isogenic lineages, providing a model fish with a natural and extreme form of kin. Using distinct strains of rivulus originating from Belize and Honduras, we predicted that rivulus would use both relatedness and familiarity as cues to recognize conspecifics. We used a choice chamber and in two separate experiments, gave focal fish of each strain the choice between related or familiar stimulus fish. We took water samples to determine cortisol concentrations, as we predicted that association with non‐kin and/or unfamiliar fish would be stressful and result in increases is the stress hormone. We found no significant differences in the proportion of time either lineage spent with familiar or related conspecifics. We further analysed association time for aggressive behaviour as we predicted that rivulus would be less aggressive to both familiar and related conspecifics. Interestingly, we determined that the Belize lineage is not aggressive towards related or unrelated individuals whereas the Honduran lineage is aggressive to unrelated conspecifics only. Collectively, our data suggest that rivulus detect conspecifics using both familiarity and relatedness; kin discrimination is not universal and appears to have a genetic basis. My further analyses will determine whether or not association with non‐kin and/or unfamiliar individuals is physiologically stressful.Support or Funding InformationResearch supported by APS UGSRF and Mount Allison University. Cortisol analysis is in collaboration with Dr. Ryan Earley, University of Alabama. Research supervised by Dr. Suzie Currie.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.