bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vitamin C Protects Against Doxorubicin‐Induced Muscle Oxidative Stress
Authors: do Nascimento Filho Antonio Viana , Stoyell‐Conti Filipe F. , Akolkar Gauri , de Miranda Victor Hugo M. , Singal Pawan , Irigoyen Maria Cláudia , De Angelis Kátia , da Silva Dias Danielle 
Published: May 2022

IntroductionDoxorubicin, has been used as a chemotherapeutic agent, however, it is also associated with significant cardiotoxicity related to an increased oxidative stress (OS). Recent studies have shown that doxorubicin also induces skeletal muscle atrophy in preclinical models. Vitamin C (VC), which presents antioxidant properties, has been used as a pharmacological approach against cardiac toxicity. Nonetheless, the effects of vitamin C on doxorubicin‐induced skeletal muscle atrophy are still unknown.ObjectiveEvaluate the effects of VC on OS parameters in skeletal muscle of rats exposed to doxorubicin.MethodsMale Wistar rats divided into 4 groups (C: Control. VC: Vitamin C. D: Doxorubicin and VCD: VC+Dox, n=8‐10/group). Dox was administered in six doses of 2.5 mg/kg, for 3 weeks to obtain a cumulative dose of 15 mg/kg. VC was administered daily (50 mg/kg) orally for six weeks, starting one week before treatment with Dox. The gastrocnemius was weighed and homogenized for OS analysis: antioxidant profile (catalase [CAT], superoxide dismutase [SOD], glutathione peroxidase [GPx] and non‐enzymatic antioxidant capacity [FRAP]), pro‐oxidant (NADPH oxidase, hydrogen peroxide [H2O2], nitrites) and cell damage (protein and lipid oxidation [LPO]).ResultsDox reduced the gastrocnemius weight, on the other hand VC prevented it (C: 1.74±0.03; VC: 1.55±0.18; D: 0.99±0.06 and VCD: 1.23±0.06 g). There were no differences in CAT, FRAP, NADPH and nitrites between studied groups. D group showed increased concentration of H2O2 compared to C and VC groups; which was not observed in the VCD group (C: 5.33±0.39; VC: 4.30±1.47; D: 8.72±1.58 and VCD: 3.66±0.73 μM H2O2). SOD was higher in the VCD group compared to the others (C: 8.29±0.61; VC: 8.38±0.48; D: 9.94±0.61 and VCD: 10.38±0.28 USOD/mg protein). GPx was higher in VC and VCD compared to C group and lower in D compared to C and VCD group (C:0.007±0.002; VC: 0.012±0.002; D: 0.009±0.001 and VCD: 0.011±0.001 nmol/mg protein). Protein oxidation was lower in C group compared to the others (C: 3.63± 0.93; VC: 6.98±0.74; D: 5.69±0.49 and VCD: 5.98±0.29 nmol/mg protein). However, LPO was higher in D group compared to C and VC groups, and lower in VCD group compared to D group (C: 342±122; VC:364±153; D: 998±131 and VCD: 389±50 cps/mg protein).ConclusionVitamin C protects against doxorubicin‐induced skeletal muscle atrophy and oxidative stress, suggesting a potential approach to management cardio functional disorder in patients under doxorubicin treatment.
Lower blood pressure, but not muscle sympathetic nerve activity, in female compared to male adults during progressive central hypovolemia
Authors: Jarrard Caitlin P. , Trotter Claire E. , Crandall Craig G. , Watso Joseph C. , Huang Mu 
Published: May 2022

INTRODUCTIONRapid adjustments in cardiac output and sympathetically‐mediated vasoconstriction are critical to prevent blood pressure (BP) from falling during central hypovolemia. Female adults have a reduced ability to tolerate central hypovolemia (i.e., orthostatic hypotension), potentially due to reduced sympathetically‐mediated vasoconstriction. However, there are minimal data evaluating sex differences in muscle sympathetic nerve activity (MSNA) during pre‐syncopal limited central hypovolemia. Therefore, the purpose of this study was to compare autonomic cardiovascular responses during central hypovolemia between sexes. We tested the hypothesis that young healthy female, compared to male, adults would have a lower tolerance to progressive hypovolemia, accompanied by attenuated MSNA responses.METHODSTwenty‐eight female (28±8 years old, 170±7 cm, 75±8 kg, BMI: 26±3 kg/m2) and 31 male (age: 30±5 years old, height: 176±6 cm, mass: 82±9 kg, BMI: 26±3 kg/m2) adults completed a staged lower‐body negative pressure (LBNP) protocol. The LBNP protocol started at minus 40 mmHg (LBNP40) and was further reduced by 10 mmHg every 3 minutes until the participant reached pre‐syncope. MSNA (radial nerve), heart rate, and BP were collected continuously throughout the protocol. LBNP tolerance was quantified as a cumulative stress index (mmHg*min) and was compared between sexes using a two‐tailed Mann‐Whitney test. MSNA, heart rate, and BP responses during LBNP were compared between sexes (LBNP stage [repeated measure] x sex) using mixed‐model analysis of variance tests.RESULTSConsistent with prior findings, female adults had a lower tolerance to progressive LBNP (female: 513±283 vs. male: 929±357 mmHg*min, p<0.0001). Due to more females reaching pre‐syncope sooner in the protocol, we compared responses during the early stages of LBNP. At these early LBNP stages (LBNP40 & LBNP50), significant interactions for heart rate and BP were observed (heart rate: p<0.0001, BP: p=0.0464). Post‐hoc analyses revealed a significantly higher heart rate (98±20 vs. 82±15 bpm, p<0.0001) and lower mean BP (80±11 vs. 87±7 mmHg, p = 0.0343) in females at LBNP50. However, MSNA burst frequency responses were not different between sexes at the assessed time points (female vs. male; Baseline: 14±9 vs. 17±10, LBNP40: 29±14 vs. 34±12, LBNP50: 34±16 vs. 35±16 bursts/min; sex: p=0.2685, interaction: p=0.2334, stage: p<0.0001).DISCUSSIONConsistent with previous reports, this study demonstrated a lower tolerance to progressive central hypovolemia in female compared to male adults. However, contrary to our hypothesis, there was no difference in MSNA burst frequency between sexes, despite lower BP in female adults during the early stages of LBNP. These findings support the need for future studies to explore other mechanisms contributing to sex differences in tolerance to central hypovolemia.
GPR30: A potential therapeutic target in Triple‐negative Inflammatory Breast Cancer
Authors: Bittman‐Soto Xavier S. , Rivera‐Lopez Adrian J. , Mendez‐Santacruz Laura A. , Peterson‐Peguero Esther A. 
Published: May 2022

Inflammatory Breast Cancer (IBC) is rare and the most aggressive subtype of all breast cancers, with reported rapid progression, poor prognosis, and a unique clinical diagnosis (blockage of lymph vessels by tumor emboli). Approximately, 40% of IBC cases are classified as triple‐negative breast cancer (TNBC), meaning they test negative for hormone receptors (estrogen and progesterone) and the amplification of the epidermal growth factor receptor 2 (HER2), which result in no effective targeted therapies to date. However, 17β‐estrogen (E2) has been found to induce a non‐genomic cellular response to enhance oncogenic phenotypes in TN‐IBC and this has been associated with the presence of alternative estrogen receptors, including a novel G‐protein coupled estrogen receptor (GPR30). Recent studies have also reported a crosstalk between GPR30 and the epidermal growth factor receptor (EGFR) signaling pathway in the presence of E2, which enhances the phosphorylation of the extracellular signal‐regulated kinase (ERK1/2) and protein kinase B (AKT), and promotes migration and invasion phenotypes in TN‐BC cells. However, the exact role of GPR30 in the non‐genomic signaling pathway in TN‐IBC remains elusive. We hypothesize that GPR30 is necessary to undergo the estrogen non‐genomic signaling pathway to induce ERK1/2 and AKT phosphorilation levels and enhance migration and proliferation activities in TN‐IBC cells after treatment with E2.MethodsWe measured phosphorylation levels of ERK1/2 and AKT kinases (by western‐blot), migratory activity (by wound‐healing assay), and tumor emboli formation (by 3D‐cell proliferation assay) after treatments in time‐points with E2 alone and in combination with G15, GPR30 antagonist drug, in TN‐IBC cells SUM149PT.ResultsThe combined G15 + E2 treatment significantly reduced E2‐induced ERK1/2 and AKT phosphorylation levels, as well as decreased migratory activity in SUM149PT cells, suggesting that GPR30 is necessary to undergo the estrogen non‐genomic signaling pathway and can regulate the ERK1/2 and AKT signaling cascade in TN‐IBC. Data acquired from these experiments will contribute to a better understanding of TN‐IBC’s molecular structure and create new opportunities to develop novel targeted therapies.
15‐Days of Therapeutic Mild Intermittent Hypoxia Improves Cardiovascular, Upper Airway and Motor Limb Function in Participants with Motor Incomplete Spinal Cord Injury and Severe Obstructive Sleep Apnea
Authors: Panza Gino , Kissine Dylan , Puri Shipra , Lin Ho‐Sheng , Matieka Jason 
Published: May 2022

IntroductionRepeated exposure to mild intermittent hypoxia (MIH) with sustained hypercapnia improves cardiovascular control in able‐bodied individuals with obstructive sleep apnea. Thus, we aimed to investigate if this treatment can improve cardiovascular function in individuals with motor incomplete spinal cord injuries (SCI). In addition, treatment with MIH improves cortical excitability, as well as, upper airway muscle and limb motor function. Consequently, we also explored if MIH improves upper airway motor function and walking endurance in individuals with motor incomplete SCI with concurrent sleep apnea.MethodsTwo individuals (age 51.0 ± 8.5) with traumatic motor incomplete SCI (T8, C6) and untreated severe obstructive sleep apnea (apnea hypopnea index 53.7 ± 34.0 events/hour) were treated with MIH for 15 days while receiving in‐home continuous positive airway pressure (CPAP) treatment. The MIH protocol consisted of twelve 2‐minute hypoxic exposures (PETO2 ≍ 50 mmHg) with PETCO2 maintained 2 mmHg above baseline. Therapeutic CPAP and the active critical closing pressure were measured before and after the 15‐day exposure period. In addition, blood pressure was measured over 24‐hours before and after the MIH protocol. Beat‐to‐beat blood pressure was measured during baseline (i.e. normoxia) prior to exposure to MIH on day 1 and day 15. Walking endurance was measured on the first and last day of the protocol prior to MIH exposure. Due to the small sample, Cohen’s D effect sizes are presented.Results24‐hour systolic (SBP), diastolic (DBP) and mean arterial (MAP) blood pressure (unit – mmHg) was reduced following 15 days of MIH (SBP: 131.4 ± 8.5 vs 113.4 ± 9.3, d= 2.0, DBP: 82.3 ± 1.4 vs 75.5 ± 3.9, d= 2.6, MAP: 98.5 ± 1.84 vs 88.0 ± 0.5, d= 9.04). Beat‐to‐beat blood pressure was also reduced following MIH (SBP: 135.3 ± 10.0 vs 116.9 ± 21.5, d= 1.2, DBP: 87.3 ± 0.46 vs 75.6 ± 3.1, d= 6.6, MAP 107.1 ± 0.4 vs 91.3 ± 7.0, d= 4.4). Additionally, an increase in indirect measures of cardiac output at rest (77.6 ± 39.9 vs 84.9 ± 30.2 L/min, d = 0.9) with concurrent reductions in total peripheral resistance (1.3 ± .7 vs 0.6 ± 0.1 mmHg*s/mL, d = 1.8) were found on the day 15. A reduction in therapeutic CPAP (11.0 ± 1.4 vs 9.0 ± 1.4 cmH2O, d= 1.4) and the critical closing pressure (4.5 ± 0.7 vs ‐0.6 ± 1.9 cmH2O, d = 3.9) was also evident following MIH. Lastly, walking endurance (155.8 ± 151.1 vs 240.5 ± 208.0 meters, d = 0.33) and walking velocity (0.4 ± 0.4 vs 0.7 ± 0.6 meters/second, d = 0.33) increased on day 15 compared to day 1.ConclusionFollowing 15 days of therapeutic MIH (i) blood pressure was reduced (ii) upper airway patency was improved and (iii) walking endurance and velocity increased in two individuals with motor incomplete SCI, hypertension and concurrent obstructive sleep apnea.
Arginine Vasopressin is not elevated in Early Pregnancy Loss
Authors: Santillan Mark K. , Shaw Kamara , Mulcahey Ashlyn , Leibold Emily , Coulter Kaylie , Funk Meghan L. , Hamilton Wendy , Brandt Debra , Santillan Donna A. 
Published: May 2022

BackgroundAdministration of arginine vasopressin (AVP) has been previously shown to influence myometrial contractility during the first trimester of pregnancy in women who were undergoing a planned therapeutic abortion. Consequently, it was hypothesized that AVP may play a role in early spontaneous pregnancy loss. AVP is made in a 1:1 molar ratio with copeptin; thus, copeptin can be used as a surrogate measure of AVP. While early pregnancy loss is likely a multifactorial problem, we sought to fill the gap in knowledge of the causes of using pre‐collected samples from pregnancies that subsequently underwent spontaneous abortion and matched controls.MethodsA retrospective case control study was performed using plasma samples from the Maternal Fetal Tissue Bank (IRB# 200910784) at the University of Iowa Hospitals & Clinics. Whole blood samples were collected (ACD‐A tubes, Becton Dickinson) at confirmation of pregnancy appointments in which a viable pregnancy was detected by ultrasound (6‐10 weeks gestation). Samples were processed and plasma aliquots were snap frozen and stored at ‐80oC until analysis. Control samples (N=67) from viable, healthy pregnancies were matched by gestational age, race, ethnicity, and body mass index to cases (N=123). Copeptin was measured by an automated immunoassay (Brahms KRYPTOR) and total protein concentration via a bicinchoninic acid (BCA) protein assay (Pierce). Copeptin concentrations were normalized to total protein in samples. Continuous variables were analyzed by T test.ResultsNo significant differences were detected in plasma samples that were collected while the pregnancies appeared viable. Copeptin was 7.2 +/‐ 6.0 mg/dL in case plasma samples and 6.0 +/‐ 3.4 mg/dL in control plasma samples (P=0.066). It is unclear if vasopressin increases acutely prior to the occurrence of spontaneous abortion.ConclusionThese results suggest that vasopressin cannot be used to identify pregnancies at risk of early loss at the time of pregnancy confirmation.
The effect of brain serotonin deficiency on breathing during sleep is magnified by age
Authors: Pho Huy , Amorim Mateus R. , Qiu Qingchao , Shin Mi‐Kyung , Kim Lenise J. , Anokye‐Danso Frederick , Jun Jonathan J. , Ahima Rexford S. , Branco Luiz G. , Kuhn Donald M. , Mateika Jason H. , Polotsky Vsevolod Y. 
Published: May 2022

Serotonin is an important mediator modulating behavior, metabolism, sleep, control of breathing, and upper airway function but the role of aging in serotonin‐mediated effects has not been previously defined. Our study aimed to examine the effect of brain serotonin deficiency on breathing during sleep and metabolism in younger and older mice.We measured breathing during sleep, hypercapnic ventilatory response (HCVR), CO2 production (VCO2), and O2 consumption (VO2) in 16‐18 week old and 40‐44 week old mice with genetic deficiency of tryptophan hydroxylase 2 (Tph2), which regulates serotonin synthesis specifically in neurons, and Tph2+/+ controls.In younger mice, Tph2knockout resulted in an increase in VCO2 and VO2 as a result of an increase in motor activity without any effect on HCVR and breathing during sleep. In contrast, in older mice, Tph2knockout caused not only increases in metabolic rate and motor activity but also weight loss, suppression of the HCVR, a decrease in maximal inspiratory flow during non‐rapid eye movement (NREM) sleep, and oxyhemoglobin desaturation during rapid eye movement (REM) sleep. Neither serotonin deficiency nor aging affected the frequency of flow limited breaths (a marker of upper airway closure) or apneas. Serotonin deficiency increased the amount and efficiency of sleep only in older animals.In older mice, brain serotonin deficiency decreases hypercapnic sensitivity leading to hypoventilation and hypoxemia during REM sleep, which were absent at younger age. The serotonin pathway may play a role in the prevention of sleep‐disordered breathing in older individuals.
Aquaporin 1 Modulates Apoptosis Susceptibility in Pulmonary Hypertension
Authors: Niedermeyer Shannon , Yun Xin , Suresh Karthik , Damarla Mahendra , Shimoda Larissa 
Published: May 2022

Pulmonary arterial hypertension (PAH) remains a fatal diagnosis despite available therapies. PAH is characterized by extensive remodeling of the pulmonary vasculature involving the formation of vaso‐occlusive lesions and a thickened medial layer of the vascular wall, both of which contain pulmonary arterial smooth muscle cells (PASMCs). We have demonstrated that PASMCs isolated from a well‐established rat model of PAH are resistant to apoptosis under both basal and stimulated conditions. The cell membrane protein aquaporin 1 (AQP1) was initially described as a water transport channel, but more recently has been implicated in other cellular functions including migration and proliferation, and in several distinct cancer types, has been associated with apoptosis resistance. AQP1 is upregulated in PASMCs isolated from rat models of PAH, although its role in apoptosis resistance is unclear. We hypothesized that increased expression of AQP1 contributes to apoptosis resistance in PASMCs.MethodsOur animal model is the Sugen‐hypoxia (SuHx) rat model of PAH in which Sugen‐5416, a vascular endothelial growth factor receptor type 2 inhibitor is injected into rats before they are placed in chronic hypoxia (10% O2) for 3 weeks, then returned to normoxia (21% O2) for 2 weeks. Control animals receive vehicle injection and are kept in normoxic (21% O2) conditions. Cells from distal pulmonary arteries are obtained via removal of the endothelium and enzymatic digestion of the tissue to obtain a pure smooth muscle population. To deplete AQP1, we transfected control and SuHx PASMCs with small interfering RNA (siRNA) directed toward either the AQP1 protein (siAQP1) or a non‐targeted sequence (siNT). Apoptosis was measured under basal conditions by Hoechst staining and visualization of DNA condensation. In complementary experiments, control PASMCs were infected with adenoviral constructs to over‐express AQP1 (AdAQP1) or green fluorescent protein (AdGFP; infection control). Cells were treated with either PBS or the apoptotic stimulus hydrogen peroxide (250 µm for 24 h). Apoptosis was again measured by Hoechst staining and visualization of DNA condensation.ResultsIn both control and SuHx PASMCs, AQP1 knock down increased apoptosis under basal conditions. In control PASMCs with increased AQP1 expression, there was no difference in apoptosis under basal conditions. To further provoke a response in these infected cells, the apoptotic stimulus hydrogen peroxide was applied; however, again there was no difference in apoptosis levels between AdAQP1 and AdGFP infected cells.ConclusionsThese data suggest that increased AQP1 may be necessary but not sufficient for apoptosis resistance. Future studies further characterizing the role of AQP1 in apoptosis resistance are necessary to understand molecular mechanisms governing resistance to apoptosis in PASMCs and provide novel pathways for new therapeutic agents targeting vascular remodeling with the potential to reverse disease.
Dysbiosis in the Mouse Esophagus Caused by CaSR Deletion
Authors: Abdulnour‐Nakhoul Solange , Nakhoul Nazih 
Published: May 2022

BackgroundWe have previously reported a mouse model, where we knocked out the calcium sensing receptor (CaSR) in the esophageal stratified squamous epithelium (EsoCaSR‐/‐) using Cre recombination. The esophageal tissues showed morphological changes including elongation of the rete pegs, abnormal keratinization and stratification, and a remarkable bacterial build‐up on the luminal epithelial surface. In addition, the barrier properties of the epithelium were altered as indicated by a decrease in cell‐cell junction proteins and increased permeability.ObjectiveWe aimed to quantify and characterize the mucosal‐associated bacterial microbiome caused by deletion of CaSR in the esophagus.MethodsTo explore the bacterial buildup in EsoCaSR‐/‐ esophageal tissue, we analyzed the mucosal‐associated bacterial microbiome and compared it to the one in control EsoCaSR+/+ mice. Total bacterial load was estimated by quantitative polymerase chain reaction (qPCR) of 16S ribosomal DNA (rDNA) using SYBER green. We sequenced 16S rRNA targeting the hypervariable V3‐V4 region and performed gene profiling and metagenomic analysis.ResultsQuantification of 16S DNA by qPCR indicated ~1.5‐fold increase in bacterial load in EsoCaSR‐/‐as compared to control. Sequencing data indicated significant changes in the microbiome composition of EsoCaSR‐/‐. Phylum P‐Cyanobacteria was increased in EsoCaSR‐/‐, family F_Burkholderiacea and order o_Betaproteobacteria were decreased. The microbe species s_Rodentibacter, s_Lactobacillus_hilgardii were enriched in CaSR KO mice while s_Curvibacter_unclassified, s__Streptococcus_equinus, s_Lactobacillus_crispatus and s_Millionella_massiliensiswere decreased. Linear discriminant analysis (LDA) detected 3 bacterial species; g‐Rodentibacter, s_Rodentibacter_unclassified,and s_Lactobacillus_hilgardi showed statistically significant and biologically consistent differences between control and EsoCaSR‐/‐ tissues. Metagenomic analysis indicated a significant decrease in metabolic pathways and bacterial enzymes.ConclusionsThis is the first report on dysbiosis caused by CaSR deletion in the esophagus. Our data demonstrate a direct in‐vivo interaction between esophageal epithelia and bacteria and could shed light on cellular factors modulating the microbiome.
The Codependent Expression of the Essential Mammalian RNA Polymerase I PAF49/PAF53 Heterodimer
Authors: McNamar Rachel , Knutson Bruce , Rothblum Lawrence 
Published: May 2022

Ribosome biogenesis (RB) is a complex process that plays a central role in maintaining cellular homeostasis and supporting cell growth. Therefore, dysregulation of RB contributes to pathologies such as cancer, ribosomopathies, neurodegenerative diseases, and aging. Our lab studies transcription of ribosomal RNA by RNA polymerase I (Pol I), the rate‐limiting step in ribosome biogenesis. Many studies have demonstrated that inhibiting Pol I transcription in cancer cells causes cell death while untransformed cells arrest, thereby making the Pol I apparatus a target for chemotherapeutic agents. This study focuses on two mammalian polymerase associated factors of the Pol I transcription apparatus, PAF49 and PAF53. The PAFs form a heterodimeric complex and are required for rDNA transcription and cell proliferation. The goal of this study is to determine the role(s) of PAF49 and PAF53 in rDNA transcription and understand how these two proteins are regulated.To rapidly knock down (KD) either PAF49 or 53 in HEK293 cells, a novel system that utilizes CRISPR/Cas 9 and an auxin inducible degron was used. Currently, we are using this system to determine if KD of PAF49 effects the expression of PAF53 and vice versa. Our data demonstrates that KD of PAF49 causes the rapid depletion of PAF53 protein levels while KD of PAF53 has no effect on PAF49. Additionally, we have found that the dimerization domain of PAF49 is not sufficient to stabilize PAF53. Rescue of PAF53 protein levels requires PAF49 to dimerize and bind to the polymerase. Dimerization to PAF53 and binding to the polymerase is also necessary to support cell proliferation and rDNA transcription. Further, KD of PAF49 or PAF53 has no effect on the protein levels of the core subunits of Pol I. These findings are significant because they aid in further understanding the process of rDNA transcription by Pol I. Additionally, they will contribute to the discovery of novel drug targets that could be utilized in effective cancer treatments. For example, disrupting the interaction between PAF49 and Pol I should inhibit Pol I transcription and cause cell death in cancer cells.