bluuebunny/crossref_metadata_2025_split huggingface dataset:
Extracellular Matrix Content and Remodeling Does Not Differ Between Higher‐Responders and Lower‐Responders to Resistance Training
Authors: Godwin Joshua S. , Ruple Bradley , Sexton Casey , Smith Morgan , Fruge Andrew , Young Kaelin , Mobley Christopher , Roberts Michael 
Published: May 2022

ObjectiveTo determine if markers of skeletal muscle extracellular matrix (ECM) content and ECM remodeling are indicators of hypertrophy in previously untrained collage aged males.HypothesesHigher‐responders (HR) to resistance training would demonstrate more malleable changes in assayed ECM markers than lower‐responders (LR).MethodsUntrained, college‐aged males (n=38, 21±3 years old) participated in 10 weeks of full‐body progressive resistance training (2x weekly) which included the leg press, bench press, leg extension, deadlift, and lat pulldown exercises. Participants completed a pre‐testing battery (DXA, ultrasound, pQCT and strength testing) and donated a vastus lateralis (VL) biopsy approximately one week prior to training. Participants completed post‐testing 72 hours following their last training bout, and this mimicked pre‐testing. Participants were then sorted into HR (n=10) and LR (n=10) based on changes in lean body mass, mid‐thigh cross‐sectional area (CSA), VL thickness, and deadlift strength changes. Muscle tissue from these 20 participants were processed for western blotting targeting MMP‐2, MMP‐9, MMP‐14, TIMP‐1, TIMP‐2, collagen‐1, and collagen‐4 protein levels. Global MMP activity was also performed on whole tissue lysates, and fascial thickness was measured from ultrasound images. All dependent variables were analyzed in SPSS (v22.0) using two‐way (group*time) repeated measures ANOVAs.ResultsNo significant group*time interactions or main effects of time were detected for MMP‐2, MMP‐9, TIMP‐1, TIMP‐2, Collagen‐1, or Collagen‐4 protein levels (p > 0.05). MMP activity and VL fascial thickness also revealed no significant group*time interactions or main effects of time (p > 0.05). A significant main effect of time (p = 0.009) and group*time interaction (p = 0.007) was detected for MMP‐14. Further analysis revealed a significant difference between HR and LR prior to training (p = 0.026) along with a significant decrease from pre to post in HR (p = 0.002)ConclusionsOur data suggest that skeletal muscle ECM markers did not differentiate higher‐responders versus lower‐responders to resistance training. However, MMP‐14 was responsive to resistance training and significantly different between response clusters prior to resistance training, and this warrants further investigation.
Skeletal Muscle LINE‐1 Gene Regulation and Inflammatory Response to Chronic, Voluntary Endurance Training in Rodents
Authors: Osburn Shelby , Mesquita Paulo , Neal Frances , Ruple Bradley , Holmes Matthew , Roberts Michael 
Published: May 2022

ObjectiveWe sought to determine the effects of chronic, voluntary wheel running on Long Interspersed Nuclear Element‐1 (LINE‐1) mRNA expression and promoter methylation, as well as markers of the cGAS‐STING inflammatory pathway, in skeletal muscle.HypothesesLINE‐1 mRNA expression will increase with age, and exercise will mitigate this increase. This difference in expression will be driven through changes in promoter methylation. The cGAS‐STING inflammatory pathway will be upregulated with age and downregulated with rats that exercise‐trained.MethodsPlantaris and soleus skeletal muscles were collected from female Lewis rats that belonged to one of three groups: a young control group (CTL; n=10; 6 mos old), an aged sedentary group (SED; n=12; 15 mos old), and an aged exercise group with access to a running wheel for 9 months (EX; n=12; 15 mos old). RNA, DNA, and protein were isolated from the tissues for analysis. Analysis included RT‐qPCR for LINE‐1 mRNA expression, methylated DNA Immunoprecipitation (MeDIP) to assess the methylation status of the LINE‐1 promoter via RT‐qPCR, and Western blotting for markers of the cGAS‐STING pathway and 4Hydroxynonenal (4HNE). Two primer sets were used for RT‐qPCR: L1‐3 probed for the most active form of LINE‐1 and L1‐Tot probed for all full‐length LINE‐1 elements.ResultsThere was no significant difference in plantaris LINE‐1 mRNA expression or for L1‐3 or L1‐Tot. Plantaris LINE‐1 promoter methylation was undetectable in most samples, so the results are not presented herein. Soleus L1‐3 mRNA was significantly higher in EX compared to CTL (p=0.036) and there was a trend between SED and EX (p=0.053). L1‐Tot also was trending (p=0.059), where EX was higher than CTL (p=0.025). Methylation of the LINE‐1 promoter was significantly different for both L1‐3 and L1‐Tot (p=0.021 and p=0.028, respectively). In both instances, LINE‐1 DNA in SED and EX were significantly more methylated compared to CTL. There were no differences in cGAS protein expression, p‐/pan STING protein expression, or 4HNE expression.ConclusionsContrary to the original hypothesis, LINE‐1 mRNA expression and DNA methylation were higher in the exercise group. Additionally, chronic exercise did not affect the cGAS‐STING inflammatory pathway, highlighting this pathway may be more relevant in extreme age and disease states. Previous skeletal muscle research has focused on using mixed muscle types to look at LINE‐1 expression and regulation, so the differences seen between type I (soleus) and type II (plantaris) fibers is a novel finding that warrants further investigation to understand the underlying mechanisms.
Time course of blood level of alpha‐1 antitrypsin over 96 hours in smokers and hypertensive patients after acute myocardial infarction
Authors: Khatib Said Y. , AlJinabi Mukhallad M. 
Published: May 2022

IntroductionAlpha ‐ 1 antitrypsin (A1AT), released from the liver, is known to protect lung tissue from damage. Some evidence suggests such protection is extended to myocardial tissues during myocardial ischemia/infarction.ObjectiveThe aim of the study was to determine the time course of A1AT levels in the plasma of myocardial infarction patients over 96 hours and compare it with healthy individuals.MethodsBlood samples were collected from patients (n=40, age 58 + 11 yrs, males 29 and females 11), at 1, 4, 24, 48 and 96 hrs after confirmed diagnosis and admission to King Salman Cardiac Center in King Fahad Medical City, Riyadh, Saudi Arabia. IRB approval and consent was signed by all patients. The patients were divided into smokers (n=10) and non‐smokers (27), Hypertensive (23) and non‐hypertensive (14). Blood samples were collected in purple top tubes containing EDTA to prevent blood coagulation and immediately centrifuged at 6000 rpm at 4 C for 20 min. Plasma was decanted and stored at – 20 C until analyzed. AlAT was determined in plasma using Eliza kits (abcam, USA).ResultsA1AT level were significantly less in smokers after an MI (1158+177 ug/ml at 96 hrs, P<0.05, n=10) compared to (1547+128 ug/ml, n=27, mean +SEM) in non‐smokers. A1AT after an MI attack was comparable in hypertensive (1179+213 ug/ml) with that in non‐hypertensive patients(1122+190ug/ml).ConclusionThe plasma levels of A1AT seem to be significantly less during an MI attack in smokers compared to non‐smoker but not in hypertensive patients where the level is compared to non‐hypertensive. From other data from this study in those patients in whom the level of A1AT dropped to more than 50 % of normal values (< 600 ug/ml) they passed away and did not survive the MI attack. It is therefore suggested that A1AT could have some protective effect on ischemic myocardium. More studies are needed to confirm this suggestion.
Famotidine exerts anti‐inflammatory effects via a vagus nerve‐dependent mechanism
Authors: Yang Huan , George Sam J. , Thompson Dane A. , Brines Michael , Pavlav Valentin A. , Andersson Ulf , Chavan Sangeeta S. , Tracey Kevin J. 
Published: May 2022

BackgroundThe COVID‐19 pandemic in the U.S. caused > 48 million infections and >500,000 deaths. Famotidine, a histamine H2 receptor antagonist widely used to treat acid reflux and gastritis, is associated with improved survival and attenuated COVID‐19 disease severity (Mather JF et al. Am J Gastroenterol. 115:1617,2020; Freedberg DE, et al. Gastroenterology 159: 1129, 2020; Janowitz T et al. Gut, 69:1592, 2020). However, the mechanism of action for these beneficial effects is unknown. As hyperactive inflammatory responses from SARS‐CoV‐2 plays a critical role in disease progression in COVID‐19, here we studied the effects of famotidine in murine models of cytokine storm.MethodsMale C57BL/6 mice were subjected to bilateral sub‐diaphragmatic vagotomy and were recovered for 7 days before experiments. Male C57BL/6 mice were given an injection of famotidine either intraperitoneally (4 mg/kg) or intracerebroventricular (0.4 mg/kg) prior to administration of LPS (7 mg/kg) given intraperitoneally. Mice were euthanized 2.5 hours after LPS administration and cytokine levels in sera were measured using ELISAs. For survival studies, male C57BL/6 mice were subjected to LPS (6 mg/kg) injected intraperitoneally followed by treatment with famotidine (intraperitoneal injection at 4 mg/kg) or vehicle (PBS) twice daily for 3 days, and survival was monitored for two weeks.ResultsFamotidine (4mg/kg, injected intraperitoneally at 30 min before LPS) significantly reduced LPS‐induced elevated serum TNF levels at 2.5 hours post‐LPS injection (serum TNF levels in LPS + vehicle = 1,491+ 129 vs. LPS + famotidine = 1,060 + 72* pg/ml, N=10 mice per group. *: P=0.001). Famotidine (4mg/kg, injected intraperitoneally, twice a day for 3 days) improved survival in endotoxemic mice (two‐week survival in famotidine group = 100% vs. 70% in the PBS‐control group, n=30/group, p=0.001). Famotidine administered intracerebroventricularly (0.4 mg/kg) also significantly reduced LPS‐induced serum TNF levels and was >10 times more potent via the intracerebroventricularly route as compared to the intraperitoneal route. Bilateral sub‐diaphragmatic vagotomy attenuated the cytokine inhibiting effects of famotidine (administered intracerebroventricularly) on LPS‐induced TNF release (serum TNF levels in LPS + vehicle = 592+ 55 vs. LPS + famotidine = 616 + 98 pg/ml, N=5 per group. P=N.S.).ConclusionsFamotidine stimulates vagus nerve’s inhibition of LPS‐induced TNF release and attenuates lethality in endotoxemic mice. These anti‐inflammatory effects require the intact vagus nerve and via a brainstem‐dependent mechanism.
Expression and Characterization of Helminthic Aminoacyl‐tRNA Synthetases
Authors: Wilson David , Kammann Molly , Qi Leo , Williams Augustus , Chihade Joseph 
Published: May 2022

Parasitic worms, broadly described as helminths, currently infect approximately 2 billion people worldwide. Existing treatment options are limited and many cause harmful side effects. We are working to characterize aminoacyl‐tRNA synthetases, enzymes that carry out an essential step in protein synthesis, as potential drug targets in these parasites. Using genomic data to predict the protein sequences, we have identified synthetases likely to differ most from human homologues. We have designed gene sequences to insert into bacterial expression vectors in order to of express, purify, and characterize the helminthic enzymes.In order to facilitate kinetic assays with these enzymes, we have made progress in adapting and improving a non‐radioactive aminoacylation assay, which couples the formation of AMP during the aminoacylation reaction to the production of NADH, which can be measured spectrophotometrically at 340 nm.
Deficiency of Ataxia Telangiectasia‐mutated Kinase (ATM) Preserves Heart Function by Affecting Cardiac Remodeling in Response to Western‐type Diet in Female Mice
Authors: Ramirez Paulina , Wingard Mary , Shook Paige , Dalal Suman , Singh Mahipal , Singh Krishna 
Published: May 2022

BACKGROUNDWestern‐type Diet (WD) and deficiency of ATM protein independently associate with heart disease. Previous work demonstrated that WD in male ATM deficient mice induces accelerated body weight gain and heart dysfunction (Am J Physiol Heart Circ Physiol. 2021;320:H2324‐H2338). Conversely, WD in female ATM deficient mice attenuates weight gain and preserves heart function (unpublished data). Here, we investigated the mechanism by which ATM deficiency preserves heart function in female mice. It is hypothesized that ATM deficiency attenuates adverse myocardial remodeling in female mice, thereby preserving heart function.METHODSFemale wild‐type (WT) and ATM heterozygous knockout (hKO) mice, aged 6 weeks, were fed with normal chow (NC) or WD for 14 weeks. Heart sections were stained with Masson’s trichrome to quantify fibrosis, TUNEL‐stained to quantify apoptosis, and WGA (wheat germ agglutinin)‐stained to quantify myocyte hypertrophy. Data were analyzed using ANOVA followed by Student‐Newman‐Keuls test.RESULTSATM deficiency associated with increased fibrosis, apoptosis (myocytes and non‐myocytes) and hypertrophy in hKO‐NC vs WT‐NC (p<0.05; n=4). WD significantly increased fibrosis in WT‐WD mice, while no increase in fibrosis was observed in hKO‐WD. WD significantly increased apoptosis in both genotypes. However, the increase in apoptosis was significantly lower in hKO‐WD vs WT‐WD (p<0.05; n=4). WD increased hypertrophy in WT group. However, the hypertrophy remained significantly higher in hKO‐WD vs WT‐WD (p<0.05; n=4).CONCLUSIONDecrease in myocardial fibrosis and apoptosis, and increase in myocyte hypertrophy may play a role in preservation of heart function in ATM deficient female mice in response to WD.
Cardioprotective Effects of Preconditioning Exercise in the Female Tumor‐Bearing Mouse
Authors: Tichy Louisa , Brantley Jason T. , Parry Traci L. 
Published: May 2022

BackgroundCancer cachexia, a metabolic wasting syndrome, affects up to 80% of cancer patients and leads to the death in up to 20% of cancer patients. While research is growing in the field, there are still no clear diagnostic criteria and cancer cachexia remains an untreated condition. Aerobic exercise has been shown to positively impact cachexia by slowing its development and attenuating muscle loss. The most effective timing, duration, and intensity of exercise as a preventative and protective measure against cancer cachexia remains questionable. Therefore, the purpose of this study was to examine the effects of preconditioning exercise as a protective measure for tumor‐mediated muscle wasting.MethodsFemale LC3 Tg+ and WT mice were randomly separated into four groups, sedentary non‐tumor bearing (SED+NT), sedentary tumor bearing (SED+T), treadmill exercise non‐tumor bearing (TM+NT), and treadmill exercise tumor bearing (TM+T). Mice underwent an 8‐week treadmill exercise training protocol (TM) or remained sedentary (SED). Next, mice were implanted with tumor cells (T group; 1x105 LLC cells in flank) or remained non‐tumor (NT) for 4 weeks. To examine the protective effects of exercise on tumor growth and muscle wasting during tumor‐mediated muscle wasting, grip strength and tumor growth evaluations were taken at baseline, 8‐week, and 12‐week time points. At the end of the 12‐week study, muscle and tumor tissue was collected and weighed.ResultsTumor bearing resulted in a significant decline in cardiac function. SED+T showed a significant decrease in fractional shortening (P < 0.05) when compared to the other groups. This coincided with an increase in beclin‐1 expression in SED+T mice. Interestingly, preconditioning exercise (exercise prior to tumor bearing) appeared to preserve cardiac function (TM+T not significantly different than SED+NT). Exercise‐mediated cardioprotection also coincided with abolished beclin‐1 signaling since this was not significantly elevated in TM+T mice. Additionally, TM resulted in a 20‐fold decrease in estimated tumor volume (P < 0.05) and a 60% decrease in tumor mass (P < 0.05) compared to SED tumors.ConclusionThe data indicate potential cardioprotective effects of preconditioning exercise on preserving cardiac structure and function, as well as regulating autophagic pathways (beclin‐1) during tumor bearing. Preconditioning exercise may be an effective and accessible treatment intervention for early‐stage cancer survivors. This data is crucial in identifying the significance of exercise and the timing of exercise as a protective measure against the detrimental effects of cancer cachexia.
Intestinal P‐glycoprotein (P‐gp) Contribution to Talinolol Pharmacokinetics in Human
Authors: Wan Christine , Ishida Kazuya , Lai Yurong 
Published: May 2022

ObjectiveUnderstanding the mechanisms of intestinal secretion and recirculation is important to the realm of drug metabolism and pharmacokinetics (DMPK). P‐glycoprotein (P‐gp), one of the major efflux transporters in the intestine, has broad substrate specificity and could contribute to the intestinal secretion/recirculation of drugs. The pharmacokinetic (PK) model incorporating intestinal P‐gp contribution will be able to accurately capture the interactions for the compounds of P‐gp substrate, allowing the model to aid in determining first in‐human (FIH) dose predictions as well as related potential drug‐drug interactions (DDIs). Talinolol, a beta‐adrenergic receptor antagonist utilized for cardioprotective and antihypertensive treatments, is a good substrate of P‐gp, and a double peak of plasma concentration has been observed. We hypothesize that intestinal secretion/recirculation by P‐gp could contribute to this unique plasma concentration‐time profile of talinolol. The aim of this study was to assess whether the double peak of plasma concentration of orally administered talinolol can be captured using physiological‐based pharmacokinetic (PBPK) modeling.MethodsThe plasma concentration‐time profiles of talinolol were obtained by digitizing literature data. The P‐gp‐mediated transport kinetics of talinolol were also obtained from Caco‐2 assays present in literature. Using the plasma concentration of talinolol data after intravenous (IV) administration, the intestinal secretion clearance (CLGI) was estimated using SimCYP (v19). After estimating CLGI, the regional absorption of talinolol affected by intestinal P‐gp was assessed using plasma talinolol concentration data after oral administration and the advanced dissolution, absorption, and metabolism (ADAM) model was subsequently generated utilizing SimCYP.ResultsCLGI of talinolol was estimated through using plasma concentration data of the drug after IV infusion reported by Schwarz et al., and CLGI was estimated to be 12.6 L/hr. This CLGI value was validated by capturing another plasma concentration‐time profile of talinolol after IV infusion reported by Westphal et al. The dual‐peak of the plasma talinolol concentration after oral administration was captured using ADAM model, but this model will be further refined to better capture this dual‐peak after oral administration of talinolol in human with consideration of regional differences of absorption and/or recirculation (i.e., more P‐gp in ileum compared to duodenum and jejunum).ConclusionA model was successfully generated to accurately capture the PK profiles of talinolol after IV administration. Further refinement of the model will be required for oral administration. The outcomes from the investigation essentially broaden our overall understanding of the processes underlying intestinal secretion and recirculation.
Characterization and Cross‐Linking of a Novel Insect Cuticle‐Like Protein with Chitin and Graphene Binding Domains
Authors: Clay Ryan W. , Mitchell Jon C. 
Published: May 2022

Chitin and carbon nanotubes can both confer extraordinary physical properties upon polymers that contain them. However, these materials are also highly insoluble in most common organic solvents, making them difficult to utilize without first modifying or functionalizing them, which can alter their properties. Natural organisms produce peptides that utilize or demonstrate affinity for these materials, which can be exploited by designing a protein capable of binding to both chitin and carbon nanotubes and of cross‐linking to form a biopolymer.The conserved 65 amino acid motif called the extended Rebers and Riddiford (R&R) Consensus found in arthropod cuticle proteins has been experimentally confirmed to confer chitin‐binding ability to recombinant proteins that include it. Similarly, a phage‐derived 12 amino acid sequence (P1) has been shown to allow including recombinant proteins to coat and solubilize unfunctionalized carbon nanotubes. This work combines these segments in a single peptide along with flexible linker domains and cross‐linking domains derived from insect cuticle proteins to create a novel double‐binding cuticle protein (DBCP). Cross‐linking can be achieved through [Ru(bpy)3]2+‐mediated photo irradiation, a method showing increased promise for the creation of dityrosine cross‐links between organic molecules. This will allow ligand‐bound proteins to form a stable matrix, capturing chitin and carbon nanotubes to form a resilient biopolymer.DBCP gene was designed and synthesized for use in heterologous expression in BL21 E. coli. Western blotting will confirm the expression and purification of the target protein. Ligand binding ability will be confirmed by solubilization assays introducing ligands to concentrated protein in common solvents. FTIR will further confirm ligand binding ability and the nature of the bonds or attractions involved. Cross‐linking will be induced using [Ru(bpy)3]2+‐mediated photo irradiation.It is anticipated that use of the R&R consensus and P1 phage‐derived peptide in conjunction with resilin cross‐linking domains will create a recombinant protein capable of binding chitin and carbon nanotubes in addition to forming dityrosine cross‐links through [Ru(bpy)3]2+‐mediated photo irradiation, resulting in a more rigid biopolymer with than commonly produced protein hydrogels, expanding the range of possible use‐cases for laboratory‐derived biopolymers.
Untangling Frizzled functions
Authors: Hollis Katie , Williams Bart 
Published: May 2022

Wnt signaling is a complex network of cellular signals with multiple downstream pathways regulated by signaling complexes comprised of combinations of the 19 Wnt ligands, 10 Frizzled (FZD) receptors, various co‐receptors and Dishevelled (DVL) second messengers. Up until now, Wnt receptors have either been functionally defined as whole families or individually by how they affect specific disease states when they are dysregulated, but the specific roles each receptor plays in Wnt signaling and activating the various pathways have yet to be fully understood.CRISPR is a powerful tool that has allowed whole families of protein isomers to be knocked out. By using cellular models that have been modified by CRISPR/Cas9 and are missing key proteins in the Wnt signaling complex, we can determine their individual functions and redundancies.We have determined that a FZD is necessary but any of the individual receptors is sufficient for DVL phosphorylation. Additionally, we have found that some Wnt signals can be rescued by single receptors, or just part of a receptor, while others seem to require multiple FZDs. The expression of these receptors is crucial for not only regulation within the Wnt family of pathways, but we also discovered a new arm of crosstalk with mTOR signaling.Wnt signaling is known to play key roles in many aspects of development, but erroneous signaling can cause diseases such as cancer and osteoporosis. Current therapeutics act as a sledgehammer and target all Wnt signaling, which leads to many off‐target effects and unintended side‐effects. Since cell surface receptors are typically the easiest to therapeutically target, FZD receptors have considerable therapeutic potential. Understanding the roles of each FZD receptor will allow us to better target individual disease mechanisms.