bluuebunny/crossref_metadata_2025_split huggingface dataset:
Perinatal Inflammation and Decreases in miR29b‐1 Expression are Associated with Structural and Functional Pulmonary Deficits in Adult Mice
Authors: Velten Markus , Britt Rodney D , Heyob Kathryn M , Welty Stephen E , Tipple Trent E , Rogers Lynette K 
Published: June 2021

BackgroundMaternal inflammation contributes to premature delivery. Premature infants routinely receive therapeutic oxygen and exhibit persistently diminished respiratory function into adulthood. The long term pulmonary consequences of perinatal inflammation are unclear.ObjectiveWe tested the hypothesis that a hostile perinatal environment induces fibrotic pathways resulting in pulmonary fibrosis.MethodsPregnant C3H/HeN mice were LPS or saline injected on embryonic day (E) 16. Offspring were placed in room air (RA) or 85% O2 for 14 d then returned to RA. PFTs, microCTs, molecular, and histological analyses were performed between E18 and 8 weeks of age.Main ResultsAlveolarization was most compromised in LPS/O2 exposed mice. Collagen staining and protein levels were increased and static‐compliance was decreased only in LPS/O2 exposed mice. 3‐D MicroCT reconstruction revealed increased tissue densies only in LPS/O2 mice. Development of fibrosis was associated with decreased miR29b‐1 expression and evidence of TGF‐β/Smad signaling during embryonic and early fetal lung development.ConclusionsSystemic maternal LPS administration induces a pro‐fibrotic response in fetal lung tissue that in combination with neonatal hyperoxia exposure depresses miR29b‐1 and activates of pro‐fibrotic pathways, resulting in impaired alveolarization, fibrosis, and compromised function in adulthood.
TRPV4 in Porcine Lens Epithelium Regulates Hyposmotic Stress‐Induced ATP Release and Na, K‐ATPase Activity
Authors: Shahidullah Mohammad , Mandal Amritlal , Delamere Nicholas A 
Published: June 2021

In several tissues TRPV4 channels are involved in the response to hyposmotic challenge. Our objective was to detect TRPV4 protein in porcine lens epithelium and its role in hyposmotic stress‐induced ATP release.The Western blot analysis showed presence of TRPV4 in the lens epithelial homogenate. The TRPV4 antagonist RN 1734 (10μM) completely prevented ATP release by lenses exposed to hyposmotic (200 mOsm) solution. Lenses exposed to a TRPV4 agonist, GSK1016790A (GSK), or to hyposmotic solution displayed ATP release and an increased ability of propidium iodide (PI) (MW 668) to enter the epithelium. The increases in PI uptake and ATP release both were abolished by a mixture of agents that block connexin and pannexin hemichannels, 18á‐glycyrrhetinic acid (AGA, 100μM) and probenecid (1mM). An increase in Na, K‐ATPase activity was detected in the epithelium of lenses exposed to GSK in isosmotic solution and the response was prevented by AGA + probenecid. TRPV4 antagonists prevented the activation of Src family kinase and increase of Na, K‐ATPase activity that occurred in the epithelium of lenses exposed to hyposmotic solution.The findings are consistent with hyposmotic shock‐induced TRPV4 channel activation which triggers hemichannel‐mediated ATP release. The results point to a pivotal role for TRPV4 activation as an initial event in a multi‐step response of the lens to hyposmotic stress.
Ubiquitination of Vesicular Acetylcholine Transporter
Authors: Li Yifan , Freeling Jessica , Sample Alex 
Published: June 2021

Vesicular acetylcholine transporter (VAChT) is responsible for transporting synthesized acetylcholine (Ach) into synaptic vesicles and thus affects Ach release at cholinergic synapses. Trafficking and distribution of VAChT in cells involves complex processes which are not fully understood. Utilizing Tandem Ubiquitin Binding Entities (TUBE) assay, we pulled down the ~70 kDa band of VAChT in samples from the SN56 cholinergic cell line, as well as from mouse brain tissues, indicating this is the ubiquitinated specie of VAChT. In SN56 cells, this ubiquitinated VAChT was increased by the treatment with a non‐selective ubiquitin isopeptidase inhibitor, PR‐619, but decreased by the treatment with an ubiquitin activating enzyme (E1) inhibitor, PYR‐41. Furthermore, manipulations of VAChT ubiquitination impacted cytosolic and membrane distribution of this transporter. Collectively, these data suggest that ubiquitination may play a role in regulating distribution and thus function of VAChT in cholinergic neurons.This work was supported by AHA grant No.0835256N, NIH INBRE grant No. P20 RR016479, NIH grant No. 1R03AG033291, and the BBS bridge grant.
Mice disrupted for the ammonia channel RhCG compensate a physiological acid load of high protein diet
Authors: Bounoure Lisa , Bourgeois Soline , Druart Sébastien , Kuhn Gisela , Müller Ralph , Devuyst Olivier , Wagner Carsten 
Published: June 2021

Ammonium (NH4+) excretion in the urine is a critical mechanism by which the kidneys clear the excess of acid from the blood. A breakdown in this process leads to metabolic acidosis, as it was observed in HCl acid‐loaded mice harboring a deletion of the ammonia channel RhCG gene. Dietary intakes enriched in protein are known to induce an acid load in both human and rodents. We used here a high protein diet (HP) to investigate the response of Rhcg +/+, +/− and −/− mice exposed to a mild physiological acid load. Metabolic parameters of these animals treated for 9 days with HP diet revealed that after 4 days, Rhcg −/− excreted 30% less urinary NH4+ than +/+, but at day 9, Rhcg −/− mice interestingly adapted fully to the diet, excreting as much NH4+ as Rhcg +/+. The mRNA and protein expression of proteins involved in renal NH4+ metabolism, SNAT3, PDG, and NKCC2 were enhanced in Rhcg +/− or −/− and both groups concentrated more NH4+ in the inner medulla than Rhcg +/+, suggesting that these mice produce and reabsorb more NH4+ to properly acidify urine after HP acid load. Finally, Rhcg −/− presented signs of bone degradation with hypercalcemia and hypercalciuria after 4 days of HP diet together with an increased release of deoxypiridinoline (a marker of bone resorption). Thus, Rhcg −/− and +/− mice handle a physiological HP acid load using specific adaptation mechanisms, however they cannot avoid bone degradation under these conditions.Supported by the Swiss National Science Foundation
Tracking of single microvilli to study regulation of the intestinal phosphate transporters
Authors: Lanzano Luca , Caldas Yupanqui , Giral Hector , Digman Michelle , Levi Moshe , Gratton Enrico 
Published: June 2021

Intestinal phosphate (Pi) uptake is a key mechanism in systemic Pi homeostasis. Modulation of intestinal Pi transport has been recently recognized as an important target in prevention of hyperphosphatemia and the associated cardiovascular complications in Chronic Kidney Disease. Intestinal Pi absorption is mainly mediated by the sodium‐phosphate co‐transporter NaPi2b expressed in the intestinal apical microvilli. Recent evidences show that agonists of the LXR nuclear hormone receptor inhibit intestinal NaPi transport activity, however, the detailed mechanisms of how LXR decreases intestinal NaPi transport activity, including the role of changes in membrane cholesterol or PDZ interacting proteins, remain to be determined.We study these processes at the molecular level applying the Modulation Tracking nanoimaging method to microvilli of live cells expressing fluorescently tagged NaPi2b. Tracking single microvilli we measure their motion, image NaPi2b distribution on the membrane and perform Fluorescence Correlation Spectroscopy techniques (RICS, N&B) in steady state, even if the microvilli are moving. Motility of the microvilli, protein diffusion and clustering, are monitored under stimulation to get insights into the process of intestinal transporters regulation.Work supported in part by NIH R01 DK066029‐01A2 (ML, EG and LL), NIH‐P41‐RR03155 (EG and LL) and P50‐GM076516 (EG, MD and LL).
Mechanism of Tumor Necrosis Factor alpha (TNFα) Inhibition of B0AT1 Mediated Glutamine Transport in Rat Intestinal Epithelial Cell (IEC‐6)
Authors: Talukder Jamil , Bayakly Nabil , Dawney Tonickee 
Published: June 2021

BackgroundTNFα inhibits B0AT1‐mediated glutamine (Gln) transport by decreasing the affinity of the transporter for Gln on the brush border membrane (BBM) of IEC‐6 cells. TNFα has been shown to exert its effect on several proteins through different signaling pathways.AimTo identify the specific signaling pathway that TNFα activates to inhibit B0AT1‐mediated Gln transport in IEC‐6 cells.MethodsIEC‐6 cells grown on 6‐well plates were treated with TNFα and/or specific inhibitors: Suramin, RpMBcAMP, Calphostin C, BAPTA, and Genistein for PKG, PKA, PKC, Ca2+ chelator, and ERK/JUNK, respectively for 24 h. B0AT1 function was determined by measuring [3H]‐Gln uptake. Cytosolic Ca2+ was measured using Flu 3AM. RTQ‐PCR and Western blot analyses were performed.ResultsTNFα decreased B0AT1 activity in IEC‐6 cells (7.1±0.1 nmol/mg protein/2 min in control and 2.9±0.1 in TNFα treated cells, n=4, p<0.01). Only Genistein fully blocked TNFα mediated inhibition of B0AT1 activity (6.9±0.1 nmol/mg protein/2 min). Kinetic studies demonstrated that the protective mechanism of TNFα mediated inhibition of B0AT1 by Genistein was due to the restoration of affinity of B0AT1 for Gln. Molecular studies showed that both B0AT1 mRNA and B0AT1 protein levels on BBM remained unaltered in all groups.ConclusionsThese studies revealed that TNFα inhibits B0AT1 through ERK/JUNK pathway most likely by phosphorylation in IEC‐6 cells.
The structure of giraffe resistance arteries from muscular beds correlates with the height above ground
Authors: Aalkjaer Christian , Broegger Torbjoern , Tilenius Niklas , Broendum Emil Toft 
Published: June 2021

The arterial pressure varies substantially within a giraffe. Giraffes, thus, provide ideal animals to test whether the structure of the resistance arteries reflects the transmural pressure. We dissected out small arteries from biopsies of leg muscles (ca. 80 cm above ground) and muscles from lower and upper neck (40 cm and 150 cm above the heart, neck1 and neck2, respectively from six male giraffes (Giraffa camleopardalis). The transmural pressures in the conduits at the three levels are ca. 300, 170 and 100 mmHg, respectively. The arteries were mounted in a myograph and normalized based on the passive length‐tension relationship. The normalized diameters of the arteries were 171±17 μm, 192±6 μm, 187±24 μm leg, neck1 and neck2, respectively, and did not differ, whereas the media thickness and force production (expressed as equivalent pressure) decreased significantly with the height above ground and were media thickness: 25±2 μm, 16±1 μm and 12±0 μm, leg, neck1 and neck2, respectively and equivalent pressure: 66±6 kPa, 52±6 kPa and 41±6 kPa, leg, neck1 and neck2, respectively.We conclude that resistance artery structure and consequently their function follows the transmural pressure.
Heart failure increases neutral sphingomyelinase activity and ceramide content in rat diaphragm
Authors: Ferreira Leonardo , Deevska Gergana M. , Nikolova-Karakashian Mariana , Yoo Jeung-ki , Christou Demetra D. 
Published: June 2021

Patients with chronic heart failure (CHF) have skeletal muscle weakness and elevated secretory sphingomyelinase activity. Sphingomyelinase (SMase) acts through ceramide to depress skeletal muscle force in vitro. We hypothesized that diaphragm weakness in CHF is accompanied by increases in SMase activity and tissue ceramide content. We studied rats 14–16 weeks after myocardial infarction (n = 5–10) and sham surgery (n = 10–13). CHF was confirmed by a decrease in left‐ventricular fractional shortening measured by echocardiography (Sham 38 ± 2%, CHF 28 ± 1%; P < 0.05). Skeletal muscle dysfunction in CHF was confirmed by decreased maximal tetanic force of diaphragm strips (in N/cm2: Sham 30 ± 0.6, CHF 26 ± 0.5; P < 0.05). CHF elicited a 27% increase (P < 0.05) in neutral SMase (N‐SMase) activity. Consistent with this finding, total ceramide content was elevated in CHF diaphragm (in pmol/mg protein: Sham, 280 ± 5 and CHF, 343 ± 16; P < 0.05)—subspecies heightened (P < 0.05) in CHF were C18, C18:1, C20, C20:1, C20:4, C22:1. Acid SMase activity was unchanged in CHF. Similarly, there were no changes in the content of either sphingosine or sphingosine‐1‐phosphate (P > 0.05). Our data suggests that increased diaphragm ceramide content is a consequence of N‐SMase activation in CHF. Activation of N‐SMase and heightening of ceramide content may contribute to skeletal muscle weakness.Funding support: NIH 1K99HL098453‐01, 4R00HL098453‐02
Administration of recombinant adeno‐associated virus vector to the diaphragm through direct intramuscular injection
Authors: Smuder Ashley J , Falk Darin J , Nelson W Bradley , Powers Scott K 
Published: June 2021

Ventilatory insufficiency due to impaired diaphragm function is the leading cause of morbidity and mortality in many conditions (e.g. muscular dystrophy). Currently, pharmacological inhibitors and genetically modified animals are used to study many diseases affecting the diaphragm. However, these methodologies are problematic due to the occurrence of off‐target effects and possible consequences of life‐long genetic alterations. Further, conventional approaches to gene transfection (i.e., plasmid injection and electroporation) are not possible due to the size and location of the diaphragm and thus alternative methods are needed to alter gene expression. Therefore, we have developed a method for the delivery of recombinant adeno‐associated virus vectors (rAAV) to the rat diaphragm via direct intramuscular injection. We hypothesized that by directly injecting rAAV we could selectively target diaphragm muscle fibers and establish a novel animal model for studying signaling pathways and also provide a strategy for effectively using gene therapy to rescue the diaphragm in disease states. Our results demonstrate that the morphology of the rat diaphragm is sufficient to allow direct injection and provide support for the use of rAAV as an intervention to study the diaphragm during conditions that promote diaphragm dysfunction.Supported by NIH RO1 HL087839 to SKP, T32 HD043730 to AJS and F32 HL095282 to DJF
Characterization of Gz‐Coupled Dopamine D3 Receptors in Gastric Smooth Muscle
Authors: Rajagopal Senthilkumar , Kumar Divya P , Bhattacharya Sayak , Grider John R , Murthy Karnam S 
Published: June 2021

Five dopamine receptors comprising Gs‐coupled D1‐like receptors (D1 and D5) and Gi/z‐coupled D2‐like receptors (D2, D3 and D4) have been cloned. Previous studies demonstrated the expression of all five receptors in the gut with selective localization of D2 receptors in the enteric neurons and D4 receptors in mucosal layer.AIMTo determine the expression of dopamine receptors in gastric smooth muscle cells and identify their signaling pathways.METHODSExpression of dopamine receptors was determined by RT‐PCR and Western blot in rabbit gastric muscle cells. G protein activity was measured by dopamine‐induced increase in Gα binding to [35S]GTPγS. Adenylyl cyclase (AC) activity was measured as increase in cAMP by RIA and muscle relaxation by scanning micrometry.RESULTSMuscle cells predominantly expressed D3, and low levels of D1, D2 and D5 receptors. Dopamine activated preferentially Gαz (and to a smaller extent Gαi3), but not Gαs, Gαi1, Gαi2, or Gαq. Consistent with activation of Gz, dopamine inhibited isoproterenol‐ or forskolin‐induced AC activity and muscle relaxation. The effect of dopamine on Gαz and AC activity, and muscle relaxation was blocked by the selective antagonist of D3, but not D2, D4, D1/D5 receptors or pertussis toxin.CONCLUSIONDopamine D3 receptors on gastric muscle cells mediate inhibition of adenylyl cyclase activity and muscle relaxation via pertussis toxin insensitive G protein Gz.
Rapamycin administration does not impair basal protein metabolism in human skeletal muscle
Authors: Dickinson Jared M , Drummond Micah J , Fry Christopher S , Gundermann David M , Walker Dillon K , Volpi Elena , Rasmussen Blake B 
Published: June 2021

We have previously shown that administration of the mTORC1 inhibitor, rapamycin, to humans blocks the increase in skeletal muscle protein synthesis (MPS) in response to resistance exercise and amino acid ingestion. Whether rapamycin administration impairs basal MPS in human skeletal muscle is unknown. Six young (26±2y) subjects were studied during two separate 4h trials, in which each trial was divided into two, 2h basal periods. The trials were identical except during one trial a single oral dose (16mg) of rapamycin was administered immediately prior to the second basal period. Muscle biopsies (vastus lateralis) were obtained at 0, 2 and 4h, marking the beginning and end of each basal period, to examine MPS, mTORC1 signaling, and markers of autophagy (LC3BI and LC3BII protein). During the control trial, MPS, whole body protein breakdown (phenylalanine Ra), mTORC1 signaling and markers of autophagy were similar between both basal periods (p>0.05). During the rapamycin trial, these variables were similar to the control trial (p>0.05) and were unaltered by rapamycin administration (p>0.05). Thus, basal protein metabolism and mTORC1 signaling were not affected by rapamycin administration. We conclude that rapamycin administration only impairs mTORC1 signaling and MPS in human skeletal muscle when combined with a stimulus such as resistance exercise or increased amino acid availability.NIAMS R01AR049877, NIA P30AG024832, NIH T32HD07539, NCRR 1UL1RR029876
Proteins controlling catabolic and stress pathways are upregulated during total knee arthroplasty
Authors: Bailey Ashley N , Hocker Austin D , Senesac Hilary A , Ratchford Stephen M , Shah Steven N , Jewett Brian A , Dreyer Hans C 
Published: June 2021

BACKGROUNDSkeletal muscle atrophy is common following total knee arthroscopy (TKA). A tourniquet is routinely used during TKA to create a bloodless field. Subsequent ischemia‐reperfusion (I/R) within muscle cells and tissue beds may activate cellular catabolic and stress pathways. We hypothesized that I/R increases gene expression and signaling proteins involved in muscle protein catabolism.PURPOSETo measure changes in transcripts and proteins involved in catabolic and stress pathways in older subjects undergoing TKA.METHODSSubjects between the ages 60–80 were studied in the operating room during surgery. Muscle biopsies were obtained at baseline (after anesthesia, immediately prior to tourniquet inflation), during maximal ischemia (just prior to tourniquet deflation), and during reperfusion.RESULTSTotal protein for FOXO3a, MAFbx, MuRF1, p‐38 MAPKs, and JNK were elevated relative to baseline during ischemia and reperfusion (p≤0.05). MAFbx, MuRF1, p‐38alpha, and JNK mRNA expression were increased during ischemia and reperfusion relative to baseline (p≤0.05).CONCLUSIONThese preliminary results suggest that I/R injury in muscle cells activates catabolic and stress pathways at the transcriptional and translational level during TKA in older adults.Support: NIH/NICHD K01HD057332.
Resveratrol Attenuates Age‐associated Functional Deterioration and Augmentation of Cardiac Fibrosis
Authors: YU Angus , Sin Thomas , Siu Parco 
Published: June 2021

Resveratrol is a potential anti‐aging compound that may preserve cardiac function with aging. This study aimed to examine the protective effects of resveratrol on age‐associated physiological deterioration and cardiac fibrosis.Adult male senescence accelerated mice were assigned to young, aged and aged with resveratrol treatment groups (n=10 per group). Mice in the resveratrol treatment group were fed with 5mg/kg/day resveratrol for 8 months. Echocardiography, endurance capacity test and basal activity test were used to assess cardiac function, resistance against fatigue and basal activity level, respectively. Masson trichrome stain was performed in ventricular muscle to determine cardiac fibrosis.Fractional shortening of aged mice was reduced by 9.4% compared to young mice (P<0.05) whereas cardiac function of resveratrol‐fed mice was similar to that of young mice. Endurance capacity and basal activity of aged mice were decreased by 94% and 44% respectively (P<0.05) but the decreases were significantly attenuated by resveratrol. The increase in percentage of fibrotic area with aging (P<0.05) was reduced by resveratrol (P<0.05).Our data demonstrate that resveratrol can ameliorate the age‐associated decline in physiological parameters and augmentation of cardiac fibrosis. Further investigation is needed to understand the precise protective mechanisms of resveratrol in the aged heart.
Association between uric acid, lean mass, and muscle strength gains in the elderly
Authors: Johannsen Neil Michael , Welsch Michael A. , Credeur Daniel , Hollis Brandon , Church Timothy S. , Allen Jason D. 
Published: June 2021

PurposeTo examine associations between UA, lean mass, and muscle strength and determine the relationship between UA and strength gains with exercise training.MethodsFifty‐two older (70+y) men and women (n=33) completed 4 wk of aerobic endurance training (AET) or regional specific exercise (RSTS). Body composition was assessed by DXA and UA was measured enzymatically. Total strength was the sum of maximal isotonic (leg and chest press, seated row) and isometric handgrip strength. AET consisted of walking and biking, 3 d/wk (45 min/session; 50–85% of HRR) and RSTS of 8 exercises (15 contractions/min for 5 min starting at 40% MVC) including all major muscle groups.ResultsMean±SD baseline age, weight, and UA levels were 74.9±4.4 y, 81.5±16.0 kg, and 5.8±1.2 mg/dl, resp. UA was associated with baseline body weight (r=0.48, P<0.001), lean mass (r=0.47, P<0.001), and strength (r=0.31, P=0.02). RSTS and men had greater strength gains (P=0.02 and P=0.001). Baseline and sex adjusted change in strength was greater in RSTS participants in the highest tertile of baseline UA (43.4±17.7 kg; mean±95%CI) compared to the low (16.0±16.2 kg) and middle (16.3±15.5 kg) tertiles within RSTS and to AET participants in the high UA tertile (19.5±16.6 kg).ConclusionUA is associated with lean mass and muscle strength and, in individuals over 70y, high UA is associated with larger strength gains after RSTS independent of sex. Research support from NIH grant 1RC1AG035822‐01 (PI‐ Jason D. Allen, PhD).
Alzheimer's disease is associated with muscle weakness
Authors: Bush Bernard , Lloyd Jesse , DeRuisseau Keith , Keslacy Stefan 
Published: June 2021

Decreased physical capacity observed in people suffering from Alzheimer's disease (AD) is associated with morbidity and mortality. The underlying mechanisms are not known.PurposeTo determine if muscle weakness occurs in an animal model of AD.Methods18 month‐old AD (APP/PS1) (n=8) were compared to WT mice (n=10). Soleus muscles were extracted under anesthesia and processed for ex‐vivo muscle function. Data were collected using a force transducer and analyzed using dynamic mechanical analysis (DMA) software. Muscle slides were assessed for Abeta accumulation using thioflavin‐S histochemical staining.ResultsWe did not observe a difference in normalized peak force for the soleus between APP/PS1 and WT animals (2.08 vs. 2.99 N/cm2 respectively, p=0.12). However, normalized specific tension was lower for APP/PS1 compared to age‐matched WT mice (13.09 vs. 18.12 N/cm2, p=0.023). Our preliminary data suggested that accumulation of Abeta occurred in the muscle of APP/PS1 animals.ConclusionAPP/PS1 mice demonstrated muscle function weakness and could represent a good model to better understand the diminished physical capacity observed in AD patients.