bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Role for the Transient Receptor Potential Vanilloid 4 Channel in Modulating Uterine Tone During Pregnancy
Authors: Ying Lihua , Alvira Cristina M. , Cornfield David N. 
Published: November 2023

BACKGROUNDThe mechanisms responsible for the sustained myometrial smooth muscle cell (mSMC) contraction in active labor are incompletely understood. Transient receptor potential vanilloid (TRPV) channels are a novel class of non‐voltage gated membrane cation channels activated by swelling, stretch, and osmotic stimuli. Previously, we demonstrated that TRPV4 channel expression in mSMC increases with gestation in rats and mouse and that TRPV4 protein expression increases disproportionately more in the membrane than cytosolic fraction of mSMC.OBJECTIVEWe hypotheses that TRPV4 channel plays a role in oxytocin induced increases in mSMC cytosolic calcium and modulates uterine contractility.DESIGN/METHODSUterine muscle strips were isolated and stimulated with oxytocin, in the presence and absence of the TRPV4 channel antagonist HC 067047 and measured the contraction responses. Control wild‐type (WT) C57/B6, TRPV4 knockout (TRPV4−/−) mice were used. Contraction tracings were recorded using the POLYVIEW. The area under the curve was calculated for the final 3 minutes of each 9‐minute contraction tracing using the LabChart Reader Software. The area under the curve for each response was then normalized to the area under the curve for the spontaneous contraction pattern over the 5‐minutes period that immediately preceded the challenge.RESULTSTo test the hypothesis that TRPV4 channel activity modulates the uterine contractile response to oxytocin, we studied the contractile response of uterine muscle strips from pregnant (day 18) WT mice exposed to increasing concentrations of oxytocin (1–1000 nM) from 1.08fold±0.96 to 3.30fold±0.39 (Area under curve, mean±SE) in the presence and absence of a specific TRPV4 channel antagonist HC 067047 (from 1.05fold±0.66 to 1.88fold±0.33), as well as the contractile response to the TRPV4 agonist, GSK1016790A. To further clarify the role of the TRPV4 channel in uterine contractility, we measured the contractile response of uterine strips derived from pregnant (day 18) TRPV4 null mice to oxytocin. Uterine strips from WT mice demonstrated a dose‐dependent contractile response to oxytocin that was attenuated by pharmacologic blockade of the TRPV4 channel. The TRPV4 channel agonist caused a dose‐dependent increase in uterine contractility. Uterine strips from TRPV4 null mice were less responsive to oxytocin than uterine strips from WT mice.CONCLUSIONSTRPV4 channel activity or expression increase oxytocin‐induced myometrial strips contraction.
Myostatin Protein and Muscle Fiber Cross‐Sectional Area are Associated with Increased Muscle Satellite Cell Number in 10 Month Old Fisher 344 Rats Treated with Testosterone and Trenbolone Enanthate
Authors: Beck Darren T. , Dalbo Vincent J. , Mobley C. Brooks , Ballmann Christopher , Kephart Wesley C. , Fox Carlton D. , Santucci Vincent A. , Beggs Luke A. , Balaez Alexander , Hoerr Frederic J. , Yarrow Joshua F. , Borst Stephen E. , Roberts Michael D. 
Published: November 2023

Influence of 5α‐reductase and/or aromatase enzymes on androgen‐induced skeletal muscle maintenance in older adults is not fully elucidated. Our purpose was to determine the androgen‐induced alterations in adult rodent skeletal muscle fiber cross sectional area (fCSA), satellite cell content, and myostatin (Mstn) signaling by comparing the effects of testosterone (TEST) versus trenbolone (TREN, a non‐5α‐reducible, non‐aromatizable synthetic TEST analogue) in 10 month old Fisher 344 rats (n=41) randomly assigned to receive Sham surgery, orchiectomy (ORX), ORX+TEST (7.0 mg/week), or ORX+TREN (1.0 mg/week). After 29 days animals were euthanized and the levator ani/bulbocavernosus (LABC) muscle complex was weighed and preserved for analyses. LABC muscle fCSA after ORX was 37% lower than SHAM and ~50% lower than ORX+TEST and ORX+TREN (p<0.01). LABC fCSA was 28% higher in ORX+TEST compared to SHAM (p=0.012). ORX+TEST and ORX+TREN increased satellite cell numbers compared to SHAM and ORX (p<0.05), with no differences between conditions for myonuclear number per muscle fiber (p=0.948). Mstn protein was increased roughly 3‐fold in the ORX+TEST and ORX+TREN groups versus Sham and ORX groups (p<0.01). Mstn mRNA, was lower in ORX, ORX+TEST and ORX+TREN compared to SHAM (p<0.05). Muscle fCSA was highly positively correlated with muscle satellite cell number (r = 0.730, p < 0.001). Mature Mstn protein was positively correlated with muscle satellite cell number (r = 0.430, p = 0.008). TEST and TREN increased muscle fCSA and satellite cell number without increasing myonuclei number, and increased Mstn protein levels. Mstn protein and Muscle fCSA were associated with increased muscle satellite cell number. TEST and TREN appear to up‐regulate Mstn protein levels to prevent uncontrolled muscle growth in older animals. In addition, the similar effects of TEST and TREN observed in the current study suggest the action of 5α‐reductase and/or aromatase enzymes are inconsequential for the androgenic maintenance of skeletal muscle in older adult males.Support or Funding InformationLABC analyses were performed at Auburn University and reagents for this study were purchased by discretionary laboratory funds from M.D.R. This study was also supported in part by work supported from the Office of Research and Development, Rehabilitation Research and Development (RR&D) Service, Department of Veterans Affairs Merit Award to S.E.B., Veteran's Health Administration Advanced Geriatrics Fellowship to D.T.B., and RR&D CDA‐2 to J.F.Y.
An investigation of the suitability of using octanoylcarnitine together with malate as a substrate combination for assessing Beta‐oxidation using High Resolution Respirometry
Authors: Osiki Prisca Ofure , Ojuka Edward Otim , Marmaan Gerald 
Published: November 2023

BackgroundBeta‐oxidation is often measured using respirometry with octanoylcarnitine + malate as substrates in cells. Malate is necessary to ensure continuous oxidation of octanoylcarnitine. However, since malate is metabolized in the TCA cycle, it is not clear if its inclusion as a co‐substrate allows for a valid assessment of beta‐oxidation when TCA cycle function is compromised.AimTo investigate the validity of beta‐oxidation assessment using octanoylcarnitine + malate as a substrate combination in skeletal muscle when mitochondrial (mt) aconitase is inhibited.MethodsSoleus muscle fibres (1.5–2mg) from healthy male Wistar rats were permeabilized with saponin and incubated for 45 minutes with 1mM oxalomalic acid (aconitase inhibitor) or 1mM 2‐mercaptoacetate, an inhibitor of MCAD – the rate‐limiting enzyme of octanoylcarnitine oxidation. Respiration at Leak, Oxphos and ETS states were measured using an Oroboros oxygraph. Citrate and 2‐oxoglutarate in the respiratory media were measured using CG‐MS. Activities of aconitase and MCAD were determined spectrophotometrically.ResultsOxalomalic acid (1mM) and 1mM of 2‐mercaptoacetate caused 24% and 58% inhibition of acnonitase and MCAD, respectively. Oxygen flux at Oxphos (0.5 ± 0.3 pmol.S−1.mg−1) and ETS (0.6 ± 0.2 pmol.S−1.mg−1) decreased in 2‐mercaptoacetate‐treated samples by 62.5% and 60%, respectively, but were unchanged with oxalomalic acid treatment. Respiration at leak state was similar for all treatments. Citrate level in the medium increased by 2‐fold at Oxphos state after 30 minutes.ConclusionOctanoylcarnitine + malate allows for a valid assessment of beta‐oxidation capacity using respirometry under conditions where mt‐aconitase has been inhibited.Support or Funding InformationSupport: 1. The research unit for Exercise Science & Sports Medicine at the University of Cape Town 2. The National Research Foundation (NRF), South Africa, for funding the research.
Cardiac Aging Concurs With Abnormal Mitochondrial Metabolism, Calcium Handling and Disrupted Levels of Mitochondrial Calcium Uniporter Complex Member Proteins
Authors: Suarez Jorge , Diaz‐Juarez Julieta , Scott Brian T. , Dai Anzhi , Dillmann Wolfgang H. 
Published: November 2023

Cardiac aging results in impaired cardiac function along with mitochondrial (Mito) dysfunction. The mechanisms for diminished function of the aging heart are incompletely investigated. Mito metabolism is regulated by free calcium concentration ([Ca2+]m) in the mitochondrial matrix. The Mito calcium uniporter complex (MCUC) is the main calcium transporter in the mitochondria. We hypothesized that Mito dysfunction could be the result of aging‐induced maladaptive changes in protein levels of the MCUC that results in deficient Mito Ca2+ handling that, in turn, impairs Mito metabolism. Therefore, the objective of this work was to determine the protein levels of members of the MCUC and analyze Mito Ca2+ handling as well as glucose oxidation (Gox). We measured protein levels by Western blot of MCU, MCUb, EMRE and MICU1/2 in hearts of young (2–3 months) and old (19–22 months) mice. In addition, we analyzed Mito Ca2+ uptake, release, and [Ca2+]m using Mito pericam. Gox was measured in an isolated “working heart” preparation. Our results showed that MCU and EMRE, which stimulate Ca2+ import, are decreased by 22% and 83% in hearts from old mice, respectively. In addition, MCUb which inhibits Ca2+ import is increased by 65% with no changes in MICU1/2. Furthermore, Mito Ca2+ uptake and [Ca2+]m were decreased by 35% and 37%, respectively. These effects of aging on Mito Ca2+ handling were consistent with reduced Gox by 45% that we measured in hearts from old mice.In conclusion, aging is associated with abnormal Mito Ca2+ handling produced by decrease in proteins of the MCUC that stimulate Mito Ca2+ uptake and increase in expression of MCUb, which inhibits Mito Ca2+ uptake. These maladaptive changes in aging result in impaired Mito metabolism and reduced Mito function in the heart.Support or Funding InformationThis work was supported by National Institutes of Health grants (5 P01 HL066941‐13), with a Merit Review Award from the Department of Veteran's Affairs (5 I01BX001121‐02) and the P. Robert Majumder Charitable Foundation. Diaz‐Juarez J. received support from UCMEXUS‐CONACYT.
The Role of Mitophagy in Doxorubicin‐Induced Cardiomyocyte Death
Authors: Weiner Ashley , Kaminaris Amanda , Kobayashi Satoru , Gerdes Martin , Liang Qiangrong 
Published: November 2023

Doxorubicin (DOX), one of the most commonly used antineoplastic agents, is effective against many cancers, but limited by its toxicities on non‐cancerous cells, especially cardiomyocytes. Although some strategies have been attempted, development of a specific therapy targeting DOX‐induced heart failure has not yet been created, largely because the mechanism remains poorly understood. DOX sets off a cellular cascade leading to mitochondrial disruption, with cell death being the ultimate event. Since mitochondrial density is up to 35% in cardiomyocytes, DOX‐induced mitochondrial malfunction can cause a serious shortage of energy supply. In this study, we investigated whether DOX treatment results in excessive elimination of mitochondria through the autophagy‐lysosome pathway known as mitophagy, and if this leads to an increase in cardiomyocyte death. Mitochondrial morphology and the levels of mitophagy in DOX‐treated H9c2 cardiac myoblasts were examined with adenovirus‐encoded mtRosella, a mitochondrial‐targeted pH sensitive dual fluorescent fusion protein. Confocal imaging analyses show that DOX enhanced mitochondrial fragmentation and increased mitophagy. To determine the underlying mechanism that mediated DOX‐induced mitophagy, we examined the expression levels of several proteins that regulate mitophagy. The serine/threonine protein kinase PINK1 and the E3 ubiquitin ligase Parkin comprise a well‐established pathway involved in the activation of mitophagy. The protein levels and mitochondrial translocation of Parkin and PINK1were all increased at 2 hours after DOX treatment, but only the effects on PINK1 were sustained at 24 hours. Parkin levels were actually reduced at this time point. These results suggest that the PINK1/Parkin pathway may contribute to DOX‐induced mitophagy and cell death. Indeed, overexpression of Parkin via adenovirus‐mediated gene transfer accelerated DOX‐induced mitochondrial morphology changes and induced mitophagy, which was associated with exaggerated cell death as indicated by propidium iodide (PI)‐uptake and cellular levels of cleaved caspase‐3 and cleaved Poly ADP ribose polymerase. Conversely, Parkin knockdown by siRNA inhibited DOX‐induced mitophagy and reduced apoptotic marker levels and PI‐uptake. These results suggest that DOX‐induced mitochondrial fission and mitophagy are detrimental to cardiac cells. Strategies that limit mitochondrial degradation through PINK1/Parkin mediated mitophagy may help reduce DOX cardiotoxicity.Support or Funding InformationThis study is supported by the following NIH grant: 1R15HL120027‐01A1
The Requirement of Cytochrome c Oxidase for Mitochondrial Fusion in Copper‐induced Regression of Cardiomyocyte Hypertrophy
Authors: Yin Wen , Li Rui , Feng Xiaorong , Kang Y. James 
Published: November 2023

Copper (Cu) supplementation reverses cardiomyocyte hypertrophy along with recovery of cytochrome c oxidase (CCO) activity and morphology of mitochondria. The present study was undertaken to test the hypothesis that Cu induces recovery of mitochondrial morphology by regulating CCO activity in hypertrophic cardiomyocytes. Primary cultures of neonatal rat cardiomyocytes were exposed to phenylephrine (PE) at a final concentration of 100 mM in cultures for 48 hrs to induce cell hypertrophy. Depressed CCO activity and fragmentation of mitochondria were observed in the hypertrophic cardiomyocytes. Cu addition to the cultures of hypertrophic cardiomyocytes at a final concentration of 5 mM for 24 hrs recovered CCO activity and led to mitochondrial fusion, along with regression of cell hypertrophy. Depression of CCO activity by siRNA targeting CCO assembly homolog 17 (COX17), a Cu chaperone for CCO, led to fragmentation of mitochondria. The COX17 deficiency‐mediated CCO depression suppressed Cu‐induced mitochondrial fusion, along with an irreversibility of cell hypertrophy. This study thus demonstrates that CCO is required for mitochondrial fusion, which is critically involved in the Cu‐induced regression of cardiomyocyte hypertrophy.Support or Funding InformationSupported by National Science Foundation of China (NSFC grant 81230004).
A High Methionine, Low Folate and Low Vitamin B6/B12 Diet Causes Neurovascular Dysfunction and Subsequent Short‐Term Memory Loss
Authors: Nuru Mohammed , Kalani Anuradha , Muradashvili Nino , Lominadze David , Tyagi Neetu 
Published: November 2023

Methionine is an amino acid found in rich quantities in proteinaceous foods such as meats, fish and eggs. This essential amino acid is high in the average American diet due to protein consumption that far exceeds the daily requirement. Besides previous studies showing a correlation between high methionine and osteoporosis, heart attacks and pregnancy complications, more recent studies are showing links between high methionine and neurodegenerative disorders such as Alzheimer's and dementia. However, the mechanisms of methionine's effects are not clear. Therefore, this study is focused on the effects of a high methionine diet on neuronal and vascular function in the brain. 8–10 week old C57BL6/J male mice were fed with a methionine enriched (1.2%), low folate (0.08mg/Kg), and low vitamin B6 (0.01mg/Kg) and B12 (10.4 μg/Kg) diet for a 6 week period. Neuronal density and their degeneration were evaluated by assessing levels of Neuronal nuclear antigen and Neuron‐specific enolase (NSE), while vascular permeability was evaluated by assessing levels of endothelial junction proteins Vascular Endothelial‐Cadherin (VE‐Cadherin) and Claudin‐5 in harvested brain tissue. Cerebrovascular permeability was assessed by evaluating microvascular leakage of fluorescently‐labeled albumin in vivo. Cognitive function of mice was determined by measuring short‐term memory using a Novel Object Recognition test (NORT). Western blot and Immuno‐histochemical analyses of neuronal‐degeneration and vascular junction markers revealed a weekly increase in neuronal and vascular damage in mice on the diet. A significant increase in neuronal damage (Integrated optical density (IOD) of NSE/GAPDH: 1.39 +/− 0.01) was found in mice on the diet for 4 weeks compared to that (IOD of NSE/GAPDH: 0.99 +/−0.02) in control animals. Vascular albumin leakage was increased and VE‐cadherin levels (IOD of VE‐cadherin/GAPDH: 0.28 +/− 0.05) was decreased in mice on diet for 6 weeks compared to vascular leakage and VE‐cadherin levels (IOD of VE‐cadherin/GAPDH: 0.48 +/− 0.02) in control mice. NORT showed a decrease in short‐term memory (discrimination index (DI): 0.45 +/− 0.15) in mice on diet for 4 weeks compared to the wild‐type control group (DI: 0.89 +/−0.13). Collectively, our results suggest that a diet containing high methionine, low folate and low vitamin B6/B12 results in increased neuronal degeneration and vascular dysfunction, leading to short‐term memory loss. Interestingly, significant neuronal damage precedes vascular dysfunction.Support or Funding InformationThis work was supported in part by NIH grants HL107640‐NT, NS084823 and P30 GM103507.
Heightened Anaphylaxis Reaction in Female Mice is Associated with Increased Synthesis of Mast Cell Secretory Granule‐Associated Immune Mediators
Authors: Mackey Emily , D'Costa Susan , Pohl Calvin , Ayyadurai Saravanan , Laster Scott , Moeser Adam James 
Published: November 2023

Sex is a critical determinant in the prevalence and severity of many diseases. In particular mast cell (MC)‐associated diseases, including irritable bowel syndrome (IBS) and IgE‐mediated allergy, are more prevalent in females. Our previous studies with murine and porcine allergy and stress models demonstrated that females exhibit more severe anaphylaxis and MC‐mediated intestinal permeability. We hypothesized that heightened disease responses in females are associated with sex‐specific differences in MC reactivity. Our objective was to determine whether MCs exhibit sex‐specific differences. Utilizing bone marrow‐derived mast cells (BMMCs) derived from female and male mice, we showed that female BMMCs exhibited greater mediator release than male BMMCs in response MC stimuli. Further experiments revealed that heightened MC granule mediator release in females was not due to increased MC degranulation signaling, but a result of female MCs increased capacity to store granule mediators. To investigate a mechanism for increased mediator content in female MCs, we performed transcriptional analysis of male and female BMMCs. Results from sequencing revealed that female MCs demonstrated higher expression of genes related to mediator synthesis and secretory granule maturation processes. Taken together, these data revealed that female MCs have increased storage of mediators, likely due to the higher expression of genes related to mediator synthesis and granule maturation factors. The findings are in line with the heightened anaphylactic response found in female mice. Uncovering the mechanism responsible for sex‐dependent differences in MCs could allow for the development of sex‐specific and more effective treatments for MC‐associated diseases.Support or Funding InformationThis research was supported, in part, by the following grants from the National Institutes of Health: R01 HD072968 (AJM), R03 DK097462 (AJM), and T35 OD011070 (EM)
17β‐Estradiol and Bisphenol‐A Exacerbate Symptoms of Dextran Sodium Sulfate Induced Colitis in Mice
Authors: DeLuca Jennifer A.A. , Allred Kimberly F. , Jayaraman Arul , Allred Clinton D. 
Published: November 2023

Inflammatory bowel diseases (IBDs) are a collection of chronic disorders associated with inflammation of gastrointestinal (GI) epithelium and autoimmune responses in the GI tract. Crohn's disease (CD) and ulcerative colitis (UC), the two main IBDs, have differing responses to increased concentrations of estrogen in women suffering from these conditions. Evidence suggests that higher estrogen exposure, such as that associated with hormone replacement therapy or normal fluctuations during menses, are related to symptom reduction in women with CD but exacerbation of symptoms in those with UC. In the Dextran Sodium Sulfate (DSS) induced model of colitis, co‐administration of estrogen has previously shown negative effects on disease activity scores in mice. The effects of xenoestrogens on DSS‐induced colitis have not been evaluated. One such xenoestrogen, Bisphenol‐A (BPA), is a known endocrine disruptor with estrogenic effects mainly via estrogen receptor β, the dominant estrogen receptor in the GI tract. In this study, we investigated the ability of 17β‐estradiol (E2) and BPA, to exacerbate colonic inflammation due to acute DSS‐induced colitis in vivo. Co‐treatment of DSS and E2 resulted in 100% mortality, with initial deaths observed 72 hours after the start of DSS treatment. DSS and BPA together resulted in 67% mortality, with most deaths between 120 and 168 hours after initial DSS treatment. Body weight, an overall indicator of disease severity, decreased significantly in E2 mice. BPA treatment also decreased body weight, with initial decrease occurring later than that observed in E2 mice. Rectal bleeding scores were most severe in E2 mice, with the greatest increase in severity between 48 and 72 hours following initiation of DSS. Between 48 and 120 hours after DSS treatment began, rectal bleeding scores of BPA mice worsened and were intermediate between E2 and control mice. Fecal consistency scores were most severe in E2 mice. Fecal scores tended to be worse in BPA mice compared to controls, but this was not significant. DSS treatment significantly decreased colon length, as expected. Ongoing analysis focuses on evaluation of cytokine expression and pathological examination of tissues. This is the first study to demonstrate that a xenoestrogen introduced through the diet can exacerbate symptoms of UC and suggests that investigating how exposure to BPA might influence UC in humans is warranted.Support or Funding InformationFunding was provided by the Center for Translational Environmental Health Research through National Institute of Environmental Health Sciences grant number P30ES023512.