bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differential expression and signaling of adenosine receptors in mouse bone marrow neutrophils
Authors: van der Hoeven Dharini , Auchampach John A. 
Published: June 2021

Adenosine suppresses neutrophil activity at sites of inflammation. Most inhibitory effects of adenosine on neutrophil function have been attributed to the A2AAR, although recently we discovered that the A3AR also plays a role. Goals of this study were to determine if exposure to inflammatory stimuli regulates A3AR expression in mouse bone marrow neutrophils (BMNs), and to explore the signaling mechanisms by which the A3AR inhibits neutrophil function. Real time RT‐PCR and radioligand binding analyses revealed that expression of the A2AAR but not the A3AR was increased ~10‐fold in BMNs obtained from LPS‐treated mice compared to controls. Despite selective induction of the A2AAR in BMNs from LPS‐treated mice, potencies of both the A2AAR‐selective agonist CGS 21680 and the A3AR‐selective agonist CP‐532,903 to inhibit fMLP‐induced superoxide production were increased compared to naïve BMNs. Mechanistic studies using naïve BMNs determined that activation of the A3AR inhibits BMN functions neither by increasing intracellular cAMP, nor by cross‐desensitizing chemoattractant or ATP receptors. We conclude that, unlike the A2AAR, A3AR expression is not induced during inflammation. In addition, we conclude that A3AR activation inhibits BMN function by a signaling mechanism that is distinctly different from the A2AAR.Supported by NIH Grants RO1 HL 077707, RO1 HL 60051 and by AHA Predoctoral Fellowship 0615533Z
Real time measurement of hydrogen peroxide (H2O2)and nitric oxide (NO) release in femoral vein ischemia and reperfusion (I/R): The effects of tetrahydrobiopterin (BH4)/dihydrobiopterin (BH2) and the effects of Protein Kinase C (PKC) epsilon activation (ε+)/inhibition (ε−)
Authors: Zambrano Christopher John , Krass Samuel , Chen Qian , Young Lindon Howard 
Published: June 2021

Endothelial nitric oxide synthase (eNOS) is a possible source of oxidative stress (i.e., superoxide (SO) and H2O2) during reperfusion in which BH4 is oxidized to BH2. Moreover, PKC ε positively regulates NO and SO release from eNOS. The effects of BH4/BH2 or PKC ε +/ε− on NO and H2O2 release have not been directly estimated by real‐time measurement in blood vessels during I/R in vivo. NO and H2O2 were directly measured by inserting either NO or H2O2 microsensors (100 μm diameter) into both femoral veins in the anesthetized rat. One femoral vein was subjected to I/R, which was induced by clamping the femoral artery and vein for 20 min ischemia followed by removing the clamp for 45 min reperfusion. The other non‐ischemic femoral vein served as a sham control in the same animal. H2O2 release increased throughout the first 20 min of reperfusion compared to the sham control. PKC ε− (0.4 mg/kg) or BH4 (6.5 mg/kg) significantly reduced H2O2 release while PKC ε+ (0.9mg/kg) or BH2 (2mg/kg) showed a trend to increase H2O2 release throughout reperfusion. BH4 significantly increased NO release while BH2 showed a trend to decrease NO release. The preliminary data thus far support our hypothesis that BH4 or PKC ε− decrease H2O2 release during reperfusion whereas the opposite effect is observed with BH2 or PKC ε+.This study was supported by NHLBI Grant 1R15HL‐76235‐01 and Center For Chronic Disorders of Aging at PCOM
The Effects of Microcirculatory Responses to Hypovolemic Shock Following Resuscitation with Colloid Solutions
Authors: Mielniczuk Mariusz Jozef , Krokowicz Lukasz , Grykien Christopher , Kusza Krzysztof , Siemionow Maria 
Published: June 2021

INTRODUCTION: Aim of the study was comparison of volume replacement with: 6% Hetastarch (HET), 5% Albumin (ALB), and 10% Pentastarch (PENT) following induction of hypovolemic shock (HS). METHODS: Rat cremaster model was used to evaluate microcirculatory changes after HS induction. Rats were randomized into groups: 1) (n=10) had parameters recorded for 4 hrs; 2) (n=10) blood withdrawn, no replacement; 3) (n=6) replaced with HET; 4) (n=6) replaced with ALB; 5) (n=6) replaced with PENT. During 4 hrs measurements of RBC velocity, vessel diameter, functional capillary perfusion (FCP) and leukocyte‐endothelial interactions, endothelial micropermeability (EMP) were recorded. RESULTS: At 4 hrs after resuscitation with HET, ALB, and PENT respectively 70%, 84%, and 85% return of FCP was recorded compared to 33 % in Group II. ALB and PENT resuscitation reduced level of sticking and transmigrated PMN's. Groups: III, IV, V presented higher tissue oxygenation than Group II (HET – 10.1 ± 0.25, ALB – 12.5 ± 0.28 and PENT 11.2 ± 0.25 vs. Group II 8.1 ± 0.15 mmHg). At 5 hrs after HS, EMP index was: Group I – 0.42; Group II – 0.86; Group III – 0.73; Group IV – 0.82; Group V – 0.7.CONCLUSIONS: After HS resuscitation with Colloid Solutions improved microcirculatory hemodynamics. ALB, and PENT administration decreased level of sticking and transmigrating PMN's. ALB and PENT have beneficial effect on vascular permeability.
Effects of CO liberated from carbon monoxide‐releasing molecule (CORM)‐2 on modulation of inflammatory response in ischemia/reperfusion (I/R)‐challenged small intestine
Authors: Katada Kazuhiro , Bihari Aurelia , Stephen Jancy , Badhwar Amit , Potter Richard F. , Cepinskas Gediminas 
Published: June 2021

CORM‐released CO has been shown to modulate inflammatory response. In this study, we assessed the effects and potential mechanisms of CORM‐2‐released CO on modulation of inflammatory response in mice small intestine following I/R. To this end mice (C57Bl/6) small intestine were challenged with ischemia by occluding SMA for 45 min. CORM‐2 (8 mg/kg; i.v.) was administered: 1) immediately before SMA occlusion or 2) immediately upon reperfusion. Sham operated mice were injected with vehicle (DMSO).Inflammatory response in the small intestine was assessed by measuring tissue levels of TNF‐[alpha] (ELISA), iNOS, ICAM‐1, and E‐selectin (Western blot) protein, accumulation of PMN (MPO assay) and the number of rolling/adherent leukocytes in the microcirculation of jejunum mucosa (Intravital microscopy) 4 hr following reperfusion.The obtained results indicate that tissue levels of TNF‐[alpha], iNOS, ICAM‐1 and E‐selectin protein expression and subsequent PMN accumulation were elevated in I/R‐challenged jejunum. The above changes were significantly attenuated in CORM‐2‐treated mice. The most potent inhibition was observed in mice, which were injected with CORM‐2 immediately before induction of ischemia.Taken together these findings indicate that CORM‐2‐released CO confers anti‐inflammatory effects in I/R‐challenged small intestine (HSFO‐NA5580 and MOP‐68848).
Increased fibrinogen content induces release of endothelin‐1 from endothelial cells
Authors: Sen Utpal , Tyagi Neetu , Moshal Karni S. , Dean William L. , Roberts Andrew M. , Tyagi Suresh C. , Lominadze David 
Published: June 2021

We previously showed that fibrinogen (Fg) increases microvascular constriction in vivo. In the present study we tested the hypothesis that Fg could cause vasoconstriction by affecting release and formation of endothlin‐1 (ET‐1) from vascular endothelial cells (EC). Fg‐induced formation of ET‐1 was studied using rat cardiac microvascular ECs. Confluent ECs were given one of the following treatments: Fg (2 or 4 mg/ml), Fg (4 mg/ml) with extracellular signal‐regulated kinase (ERK) kinase inhibitors (PD98059, or U0126), Fg (4 mg/ml) with an antibody against intercellular adhesion molecule‐1 (ICAM‐1), or medium alone for 45 min. The amount of formed ET‐1 in the cell growth medium was measured by ELISA. Fg caused a dose‐dependent increase in ET‐1 production from ECs. Fg‐induced ET‐1 production was inhibited by ERK kinase inhibitors and by the antibody to ICAM‐1. These data suggest that Fg‐induced vasoconstriction may be mediated through increased release and formation of ET‐1. This mechanism may help to explain a role of Fg in contributing to increased microvascular constriction during diseases such as hypertension, stroke, and diabetes that are accompanied by an increased blood content of Fg.Supported by NIH grant# HL080394 to DL.
The geranylgeranyl‐transferase inhibitor GGTI‐286 does not reproduce rosuvastatin‐induced delayed preconditioning against oxygen‐glucose deprivation (OGD) in cultured rat cortical neurons
Authors: Domoki Ferenc , Kis Béla , Gáspár Tamás , Bari Ferenc , Busija David W 
Published: June 2021

Rosuvastatin (RST) has been recently shown to induce resistance against OGD via depletion of geranylgeranyl pyrophosphate (GGPP) rather than cholesterol levels in cultured neurons. RST also induces GGPP‐sensitive, reversible mitochondrial depolarization, decreased NADH/NADPH and ATP levels, and these alterations may contribute to the OGD‐resistant phenotype. Our purpose was to determine if pharmacological inhibition of protein geranylgeranylation with GGTI‐286 would reproduce the neuroprotective and metabolic effects of RST preconditioning.Primary cortical neuronal cultures were obtained from E18 Sprague‐Dawley rat fetuses, and were treated with GGTI‐286 (1–10μM) for 3 days before exposure to 3h OGD. GGTI‐286 did not provide protection against OGD. Cell viability determined 4 days after OGD (untreated vs. 5μM GGTI‐286, mean±SEM, n=8–32) was 34±1% vs. 39±1% of normoxic controls. Interestingly, GGTI‐286 (5μM) reduced mitochondrial membrane potential to 80±1%*, and neuronal NADH/NADPH to 79±3%* of control levels (*p<0.05, n=8–32) similarly to RST, but unlike RST, did not affect neuronal ATP levels. In summary, GGTI‐286 is able to replicate some but not all of the GGPP‐sensitive metabolic effects of RST and does not yield OGD resistance. Reduction in ATP levels appears to be crucial in RST‐induced preconditioning against OGD. Supported by OTKA K68976, K63401 and by NIH HL30260, HL65380, HL77731.
Testosterone Activates mTOR/S6K1 Pathway Through Intracellular Calcium and ERK in Cardiomyocytes
Authors: Altamirano Francisco , Oyarce Cesar , Silva Patricio , Estrada Manuel 
Published: June 2021

Testosterone has anabolic effects on heart, but the molecular mechanisms are unknown. The mammalian target of rapamycin (mTOR) is a nutrient sensor that regulates protein synthesis and it is a convergence point for several pro‐hypertrophy stimuli. We investigated testosterone effects on mTOR in neonatal ventricular cardiomyocytes. Testosterone increased both mTOR phosphorylation and its downstream targets S6K1 and 4E‐BP1, effects blocked by rapamycin and mTOR siRNA. The hormone increased both ERK1/2 and Akt phosphorylation, which were inhibited with PD98059 and Akt‐inhibitor‐X, respectively. Testosterone‐induced S6K1 phosphorylation was only blocked by ERK1/2 inhibition. Intracellular calcium chelator BAPTA‐AM or parvalbumin protein overexpression inhibited ERK1/2, S6K1 and 4E‐BP1 activation. Stimulation of cardiomyocytes in Ca2+‐free medium or inhibition of Ryanodine receptor did not modify ERK or S6K1 activation. However, inositol 1,4,5‐trisphosphate (IP3) pathway inhibitors (U‐73122, 2‐APB and Xestospongin C) blocked the activation of ERK and mTOR pathway. In addition, pertussis toxin inhibited ERK1/2 and S6K1 phosphorylation. Testosterone activation of mTOR pathway in cardiomyocytes could be important to understand the anabolic effects of this hormone.Fondecyt 1060077, FONDAP 15010006
The slingshot family of phosphatases mediates cofilin activation during PDGF‐induced migration in vascular smooth muscle cells
Authors: Torres Rebecca Ann , Drake Doulas , Weber David S 
Published: June 2021

Platelet‐derived growth factor (PDGF) is a potent regulator of vascular smooth muscle cell (VSMC) migration. While a variety of signaling mechanisms have been reported during VSMC migration, ultimately the regulation of cell motility is via the actin cytoskeleton. We hypothesized that cofilin, a protein that facilitates actin depolymerization, is a key mediator of PDGF‐induced VSMC migration. In cultured rat aortic VSMCs, protein regulation was determined by immunoblotting with phosphospecific antibodies and migration was quantified using a modified Boyden chamber assay. Cofilin activity is increased by dephosphorylation at ser3, a process balanced by the dual regulation of LIM‐Kinase and the Slingshot family of phosphatases (SSH). Immunoblotting studies confirmed that PDGF increased cofilin activity in a time and dose dependent fashion. Relative to non‐treated control VSMCs, PDGF significantly increased VSMC migration (3.3 ± 0.4 fold), whereas in VSMCs treated with cofilin siRNA, PDGF‐induced migration is virtually eliminated (0.8 ± 0.1). The knockdown of SSH1 expression by siRNA resulted in attenuated PDGF‐induced activity of cofilin (∼80% inhibition) and a significant reduction in PDGF‐induced VSMC migration (4.4 ± 1.5; control vs 1.1 ± 0.7; siSSH1). Thus, these studies demonstrate that VSMC migration following PDGF stimulation is mediated by the SSH1 regulation of cofilin activity.AHA 0330019N
PAR‐2 receptor‐induced intracellular signalling in isolated intact human eccrine sweat gland cells and primary tissue culture cells
Authors: Bovell Douglas L. , Corbett Alistair D. , Lang Roland 
Published: June 2021

PAR‐2 receptors can evoke intracellular signalling and anion transport in a cell line derived from human sweat glands, however, it is unknown whether PAR‐2 receptors are present and play a role in intact human sweat gland secretory cells. PAR‐2 receptors were investigated in isolated sweat glands and tissue culture cells derived from primary explants. Skin samples were obtained by informed consent and ethics approval from volunteers for immunohistochemistry and sweat gland isolation for; Western blot analysis; calcium imaging or explanted for tissue culture. Immunohistochemistry and Western blot using an anti human PAR‐2 antibody demonstrated the presence of these receptors in sweat gland secretory cells. Calcium imaging experiments using trypsin and the agonist peptide SLIGKV showed that both could increase intracellular calcium levels in intact glands and in the primary sweat gland cultures. Results also demonstrated that the effects of the agonist peptide were reversible upon washout, but not trypsin, and that the reverse peptide VKGILS failed to initiate changes in intracellular calcium. The results of this study demonstrate that PAR‐2 receptors are present in isolated human sweat gland secretory cells and in primary cultured cells and that these receptors are functionally active and can induce increases in intracellular calcium.The study was supported by Glasgow Caledonian University.
Nitric oxide synthesis in neutrophil precursor cells and effect of nitric oxide modulators on their maturation
Authors: Kumar Sachin , Gupta Kanishka , Barthwal Manoj Kumar , Dikshit Madhu 
Published: June 2021

Neutrophil maturation in bone marrow and their release in circulation have been shown to be modulated by nitric oxide (NO). Present study was undertaken to further assess the role of NO in neutrophil maturation in vitro. Neutrophil precursor cells were isolated from Sprague Dawley rat (200–250 g) bone marrow by Percoll density gradient in myeloblasts/promyelocytes rich band 3, myelocytes/metamyelocytes rich band 2 and band cells/segmented Neutrophils rich band 1, purity was confirmed by Giemsa staining/CD markers, NADPH oxidase and myeloperoxidase activity.Intracellular NO level (assessed by DAF‐2DA), total nitrite (measured by Griess reagent) content, NOS activity (using 3H‐L‐arginine) and nNOS protein (Western blotting) were highest in band 1 and lowest in band 3. We also investigated effect of NO donor (SNP 1μM‐1mM) and NOS inhibitor (L‐NAME 1mM) on cell cycle by using Propidium iodide and BrdU staining during their culture for 24 hrs. SNP treated cells exhibited an increase in apoptosis, while viable cells showed a marginal increase in the S phase in band 2 and band 3. NOS inhibitor (L‐NAME) however increased the survival of cells without any modulation of cell cycle. Results obtained indicate that NO content augment with neutrophil maturation and seems to play an important role in the maturation of neutrophils.The work was supported by CSIR and DBT India.
Effects of endurance training on energy substrate partitioning during exercise in postmenopausal women
Authors: Zarins Zinta Arija , Fattor Jill A. , Wallis Gareth A. , Mau Tamara L. , Faghihnia Nastaran , Horning Michael A. , Brooks George A. 
Published: June 2021

PURPOSE: To examine the effects of endurance training on changes in energy substrate partitioning during exercise in sedentary, but otherwise healthy, postmenopausal women. METHODS: Ten postmenopausal women (aged 55±1 yr) completed 12 weeks of endurance exercise training [5 days/wk, 1 h/day, 65% peak oxygen consumption (VO2peak)]. Whole‐body energy substrate partitioning was determined by indirect calorimetry during 60 min cycle ergometer exercise in one pre‐training exercise trial [65% VO2peak, PRE] and two post‐training exercise trials [65% pre‐training VO2peak (ABT) and 65% post‐training VO2peak (RLT)]. RESULTS: Endurance training increased VO2peak by ∼16% (1.69±0.08 to 1.95±0.08 l/min, P<0.01). Compared to PRE (0.96±0.02), respiratory exchange ratio was reduced during exercise at ABT (0.93±0.01, P=0.01 vs. PRE), but not RLT (0.95±0.01). Accordingly, endurance training reduced the %energy from carbohydrate and increased the % energy from lipid during exercise at ABT (both P<0.05 vs. PRE), but not RLT. CONCLUSION: In sedentary, healthy postmenopausal women, endurance training increased peak aerobic capacity and lipid utilization during endurance exercise at a given absolute workload.Supported by NIH grant AR42906.
Wnt3a promotes β‐catenin signaling and myotube formation during myogenic differentiation
Authors: Langen Ramon , van der Velden Jos , Kelders Marco , Laeremans Hilde , Schols Annemie 
Published: June 2021

Satellite cells are muscle precursor cells required for postnatal skeletal muscle growth and regeneration. Glycogen Synthase Kinase 3beta (GSK‐3beta) has been implicated in negative regulation of skeletal muscle growth and muscle differentiation. Two distinct cellular pools of GSK‐3beta are selectively inhibited by IGF‐I/Akt‐or canonical Wnt signaling, respectively. Since canonical Wnt signaling and subsequent stabilization of beta‐catenin is involved in embryonic muscle formation, the effects of Wnt3a on differentiating myoblasts were investigated, and compared to those resulting from GSK‐3beta inactivation by LiCl or IGF‐I.Wnt3a promoted C2C12 myoblast fusion, and induced beta‐catenin signaling in a time and dose dependent fashion. In addition, beta‐catenin‐dependent transcriptional activation was also induced after GSK‐3beta inhibition using LiCl, but not by IGF‐I. Furthermore, stimulation of muscle gene expression was only observed in response to LiCl but not Wnt3a, which uncouples the promoting effects of Wnt3a on myoblast fusion from muscle specific gene expression.These data suggest that myoblast fusion and muscle specific gene expression are controlled by distinct cellular pools of GSK‐3beta, and provide evidence for a role of GSK‐3beta as a central regulator of muscle differentiation.This work was supported by a research grant of the Netherlands Astma Foundation (NAF 3.2.02.63).
Neuregulin minimizes protein degradation induced by dexamethasone
Authors: Argadine Heather , Hellyer Nathan , Mantilla Carlos , Bailey Jeffrey , Sieck Gary 
Published: June 2021

Neuregulin (NRG) is part of the epidermal growth factor family of proteins. Previous studies have shown that NRG activates PI3K/Akt pathways, leading to regulation of protein synthesis via downstream regulation of translation initiators. The principal translation initiator involved in protein synthesis is probably eIF4E, and the principal transcription factor regulating protein degradation is FOXO. We hypothesized that NRG signaling involves activation of the PI3K/Akt pathway, thus leading to an increase in expression of eIF4E and a decrease in expression of FOXO. An increase in eIF4E expression increases protein synthesis, and a decrease in FOXO expression reduces protein degradation. In this study we used dexamethasone, a synthetic glucocorticoid, to induce atrophy and cause an imbalance between protein synthesis and degradation in L6 myotubes. As expected, we found that after 48 hours of treatment with 10–100nM dexamethasone, eIF4E expression decreased and FOXO expression increased in a dose‐dependent manner. We found that treatment with 200 ng/ml NRG increased eIF4E expression. When L6 cells were treated with both NRG and dexamethasone for 48 hours, NRG blunted the catabolic effects of dexamethasone, thus increasing eIF4E expression and decreasing FOXO expression. These results indicate that NRG promotes protein synthesis and prevents protein degradation.Supported by NIH grant AR51173.
Expression of genes regulating protein synthesis in young and old human muscle following resistance exercise and essential amino acid ingestion
Authors: Drummond Micah J , Miyazaki Mitsunori , Fry Christopher S , Dreyer Hans C , Pennings Bart , Dhanani Shaneen , Volpi Elena , Esser Karyn A , Rasmussen Blake B 
Published: June 2021

Muscle growth requires an increase in both transcription and translation which results in enhanced muscle protein synthesis. The purpose of this study was to determine whether genes associated with the myogenic program and muscle protein synthesis are differentially expressed in old and young human skeletal muscle after a bout of resistance exercise and essential amino acid (EAA) ingestion. Twelve subjects (6 young, 6 old) completed 8 sets of leg extension exercise (70% 1RM) and muscle biopsies were obtained before and at 1, 3, and 6h post‐exercise. Subjects consumed a 20g leucine‐enriched EAA solution at 1h post‐exercise. RNA was isolated from biopsies and mRNA expression was determined using qRT‐PCR. At baseline, mRNA expression of Myogenin, TSC1/2, and Rheb were greater in old than young (P<0.05). Exercise resulted in increased levels of MyoD mRNA and decreased REDD1 and REDD2 mRNA in both groups (P<0.05). Myogenin mRNA increased at 3 and 6h and IGF‐1 mRNA increased at 6h only in young (P<0.05) suggesting that some genes are more responsive in young muscle following exercise. We conclude that reduced REDD1 and REDD2 mRNA levels are consistent with prolonged elevation of mTOR/S6K1 signaling and protein synthesis following resistance exercise and EAA ingestion in both young and old human muscle. Our data provides new insights into regulation of genes important for transcription and translation in young and old muscle.Funded by NIH grant # P30 AG024832, R01 AR049877, and R01 AR045617