bluuebunny/crossref_metadata_2025_split huggingface dataset:
PPAR‐γ activation inhibits TNF‐α induced NF‐κB activity in skeletal muscle
Authors: Remels Alexander , Langen Ramon , Schrauwen Patrick , Gosker Harry , Schols Annemie 
Published: June 2021

Peroxisome proliferator‐activated receptor γ (PPARγ) has anti‐inflammatory properties which, in part, rely on its ability to modulate signaling by the cytokine‐inducible transcription factor NF‐κB. NF‐κB activation has been causally related to skeletal muscle atrophy, which is a characteristic of several chronic inflammatory diseases. The goal of this study was to evaluate if PPARγ activation affects TNF‐α induced NF‐κB activity in skeletal muscle cells. C2C12 Myoblasts with a genomically integrated NF‐κB luciferase reporter construct were differentiated during 6 days into myotubes. TNFα (1ng/ml, 4h) induced an 8‐fold increase in NF‐κB transcriptional activity. Pre‐treatment of the myotubes with the specific PPARγ agonist rosiglitazone significantly lowered TNFα induced NF‐κB transcriptional activity in a dose and time dependent fashion, with a maximal inhibitory effect of 80% (150 μM, 1h pre‐incubation). Similar effects were observed when a structurally unrelated PPARγ agonist was applied, or in response to IL‐1β‐induced NF‐κB activation. In addition, a significant decrease in mRNA levels of the NF‐κB target genes ICAM‐1 and KC was observed. These results demonstrate that NF‐κB activation by pro‐inflammatory cytokines in skeletal muscle can be suppressed by PPARγ agonists, which may be a new venue for therapeutic targeting of skeletal muscle atrophy.This abstract was sponsored by Numico Research
Chromatin modification and remodeling during repair of a double‐strand break
Authors: Haber James , Hicks Wade , Kim Jung‐Ae , Dotiwala Farokh , Coïc Eric , Li Jin 
Published: June 2021

A single double‐strand break (DSB) can be induced synchronously in a population of budding yeast, allowing us to monitor the kinetics of repair and the dynamics of DNA damage‐induced chromatin modification. When a DSB is induced at the MAT locus, it can be repaired by recombining with the heterochromatic donor loci, HML or HMR. The two donors are in competition with each other, but surprisingly the donor choice is not changed when one of the donors is unsilenced. Nevertheless, there are substantial chromatin changes when the Rad51‐coated single‐stranded DNA at the resected end of MAT invades the heterochromatic donor. These changes can be seen by analysis of the protection of MNase‐resistance of nucleosome‐bound sequences. Although strand invasion and synapsis occur in cells lacking the Swi2/Snf2 homologue, Rad54, we find important differences in the alterations of nucleosome protection relative to wild type cells.A single DSB provokes modification of about 50 kb of chromatin around the DSB by phosphorylation of histone H2AX (γ‐H2AX) by ATM or ATR. Heterochromatic regions are refractory to modification but do not prevent spreading of γ‐H2AX beyond such regions. γ‐H2AX can be removed by 5′ to 3′ resection of the DSB ends (moving about 4 kb/hr) but also in a more rapid and concerted fashion when the DSB is repaired. Once liberated from chromatin γ‐H2AX is dephosphorylated by Pph3. The roles of various chromatin remodeling complexes in the removal of γ‐H2AX will be discussed. A second modification, independent of ATM/ATR kinases, is the casein kinase II‐dependent phosphorylation of histone H4‐S1. Unlike γ‐H2AX, γ‐H4 is not constitutively found near telomeres. The kinetics and extent of spreading of “γ‐H4” are markedly different from γ‐H2AX. Strikingly, γ‐H4 is found very close to the DSB site, even when these regions appear to be resected and single‐stranded. The loss of γ‐H4 when the DSB is repaired also exhibits different kinetics. The role of phosphatases and chromatin remodelers in γ‐H4 dynamics are under investigation.
Chronic intermittent hypoxia inhibits proteolysis in juvenile rat skeletal muscle
Authors: Fabio Thiago L. , Zanon Neusa M. , Kettelhut Isis C. , Bonagamba Leni G. , Machado Benedito H. , Navegantes Luiz Carlos C. 
Published: June 2021

Catecholamines exert anti‐proteolytic effects on rat skeletal muscle in basal conditions. Considering that hypoxia is a powerful stimulus of the sympathetic nervous system, the present study was undertaken to examine in juvenile rat isolated muscles the possible changes in proteolysis that occur after chronic intermittent hypoxia (CIH). For this, 3‐week‐old rats were exposed to 9 days of CIH (6% O2 for 40s at 9 min intervals; 8 h day−1). On the 10th day the weight of CIH was smaller than control rat (83 ± 2 vs 91 ± 2 g). In both soleus and extensor digitorum longus (EDL) muscles, rates of overall proteolysis (nmol Tyr·mg wt−1·2h−1) decreased after CIH. The fall in the rate of protein degradation in soleus and EDL was accompanied by a 50% and 25% decreased activity of Ca2+‐dependent (0,047 ± 0,016 vs 0,100 ± 0,013) and Ubiquitin‐proteasome proteolysis (0,035 ± 0,005 vs 0,047 ± 0,003), respectively. In vitro rates of protein synthesis (nmol Tyr·mg wt−1·2h−1) in soleus from hypoxic rats decreased by 35% (0,371 ± 0,009 vs 0,273 ± 0,016). CIH increased by 75% the content of glycogen (%) in liver (8,9 ± 0,5 vs 5,1 ± 0,3) and soleus (0,71 ± 0,06 vs 0,41 ± 0,02). These data suggest an inhibitory control of intracellular proteolytic systems by adrenergic system and/or insulin in rat muscles exposed to CIH, which may prevent additional loss of body weight during hypoxia on this critical period of the development.Financial support: FAPESP and CNPQ
TRPV4 channels contribute to ATP‐stimulated calcium influx in endothelial cells
Authors: Marrelli Sean P 
Published: June 2021

Objective: We examined the role of TRPV4 channels in ATP‐stimulated Ca2+ influx in endothelial cells (ECs) of the carotid artery (CA).Methods: Rat CAs were harvested, cut into segments, and organ cultured for three days with TRPV4 siRNA to selectively knockdown TRPV4 protein. Mock transfection and scrambled siRNA controls were performed in parallel. Knockdown was confirmed by real‐time PCR, Western, and immunofluorescence. Intracellular free Ca2+ concentration was measured (fura‐2) in response to ATP in ECs isolated from organ cultured arteries.Results: TRPV4 mRNA and protein were significantly knocked down in whole CA in the TRPV4 siRNA group. EC‐specific expression of TRPV4 from organ cultured arteries was also significantly reduced in the siRNA group compared with control (immunofluorescence). Next, endothelial Ca2+ responses to 4α‐PDD (a TRPV4 channel opener) and ATP were evaluated in mock and TRPV4 siRNA transfected arteries. The EC Ca2+ increase to 4α‐PDD was significantly reduced (~50%) following TRPV4 knockdown, demonstrating significant functional loss of TRPV4 channels. Finally, stimulation with ATP revealed a significant reduction in the sustained Ca2+ influx component whereas peak Ca2+ responses were unchanged.Conclusion: These results demonstrate that ATP‐stimulated Ca2+ influx in CA endothelial cells is partially dependent on TRPV4 channels. (AHA 0665100Y and 0230353N)
Angiotensin system is mediating cardiac oxidative stress and p38 expression in SHR
Authors: Bertagnolli Mariane , Viegas Vinicius Urbano , Janner Daiane , Casali Karina Rabelo , Ribeiro Maria Flávia , Belló‐Klein Adriane , Rigatto Katya , Irigoyen Maria Cláudia 
Published: June 2021

The objective was to determine the effect of treatment with an ACE inhibitor, enalapril (EN), on cardiac oxidative stress. Male Kyoto and SHR (15 wks) were treated for 10 weeks with EN or control (gavage, 10 mg/kg, n = 7/group). After treatment, blood pressure (BP) and heart rate were recorded from an arterial catheter (Windaq, 2KHz). Rats were euthanized with collection of heart with measurement of cardiac index (ventricle weight/body weight; mg/g), chemiluminescence (CL) and carbonyl assay. Akt and MAPK (Erk and p38) expression were assessed by Western blot. Results are presented as mean ± SD (table). In SHR, enalapril reduced BP, cardiac hypertrophy and p38 expression, probably due to a decreased cardiac oxidative stress caused by renin‐angiotensin system.Supported by: CNPq and FAPERGS.
Collagen metabolism and renal damage in 2k1c rats
Authors: Skogstrand Trude , Hultström Michael , Iversen Bjarne M. 
Published: June 2021

We have found a clear difference in gene expression for the enzymes of collagen metabolism between the inner and outer renal cortex in old spontaneously hyptertensive rats with renal damage. The progress of fibrosis in 2k1c rats is less well studied. In the present study we have investigated 2k1c rats six weeks after clipping using western blot and real time PCR to compare the gene and protein expressions in the inner and outer cortex. Using real‐time PCR we studied collagen type‐1‐A1, procollagen‐n‐ and ‐c‐peptidase, MMP‐2, MMP‐9, TIMP‐1 and ‐2. This was complemented with protein quantification using western blot for MMP‐9 and TIMP‐2 as well as the superoxide dismutases EC‐SOD and MN‐SOD.No differences were found between the inner and outer cortex of the kidney for any of the genes and no difference was found between the expressions in 2k1c and controls. This while the systolic pressure after six weeks was 126±2 mmHg in controls and 150±4 mmHg in the 2k1c rats.Our conclusion is that: While 6 weeks is pleny of time for hypertension to develop, it is not enough for the collagen metabolism to be significantly altered at the gene expression level.The study was founded by Helsevest, Norway.
Salt sensitive modulation of the interaction between efferent and afferent renal nerve activity mediated by PGE2 and endothelin (ET)
Authors: Kopp Ulla , Cicha Michael , Smith Lori 
Published: June 2021

Increases in efferent renal sympathetic nerve activity (ERSNA) increase afferent renal nerve activity (ARNA) which in turn decreases ERSNA via activation of the renorenal reflexes in the overall goal of maintaining low ERSNA to limit sodium retention. We examined if dietary sodium modulates the interaction between ERSNA and ARNA and the norepinephrine (NE)‐induced activation of renal sensory nerves. Thermal cutaneous stimulation (HOT) to increase ERSNA was produced by placing the rat's tail in 47 and 49°C water in rats fed high sodium (HNa) and low sodium (LNa) diet (lower heat activation threshold in HNa vs LNa rats). HOT increased ERSNA and ARNA 100120 ± 1830 and 7660±1380 % sec (AUC) in HNa rats and 4370 ± 1290 and 970 ± 420% sec in LNa rats. In isolated renal pelvises from HNa rats, NE 10 pM increased the release of substance P from 7 ± 1 to 12 ± 2 pg/min and PGE2 from 67 ± 1 to 150 ± 13 pg/min. In pelvises from LNa rats, NE 10‐6250 pM had no effect. Renal pelvic administration of the ET B receptor (ETB‐R) antagonist BQ788 blocked the ARNA response to HOT by 76 ± 6% in vivo and the NE‐induced increases in substance P and PGE2 by 65 ± 16 and 34 ± 15% in vitro. Conversely in LNa rats, the ETA‐R antagonist BQ123 enhanced the ARNA response to HOT from 970 to 7360 ± 2124 % sec and the renal pelvic release of substance P produced by NE 6250 pM. NE increased substance P release from 5 ± 0 to 7 ± 1 pg/min (NS) before and from 5 ± 1 to 9 ± 1 pg/min (P<0.01) during BQ123. BQ123 had no effect on the NE‐induced release of PGE2. BQ788 and BQ123 have no effect in normal sodium diet rats.Conclusion: Activation of ETB‐R contributes to the increased PGE2 synthesis and increased interaction between ERSNA and ARNA in HNa rats. Activation of ETA‐R contributes to the decreased interaction between ERSNA and ARNA in LNa rats by a mechanism distal to PGE2 synthesis.
Cardiovascular autonomic control in healthy adolescents
Authors: da Silva Prado Juliana Martuscelli , da Costa Priscila Standke , Marmo Denise Barbieri , Martins Luiz Eduardo Barreto , Gallo‐Junior Lourenço , Golfetti Roseli 
Published: June 2021

The purpose of this study was to identify differences in cardiovascular autonomic control in a sample of healthy adolescents. We studied 58 adolescents (21 females, 37 males) between the ages of 11–18. Heart rate variability (HRV) measures were adopted to assess autonomic heart rate function. The short‐term HRV in the time and frequency domains was obtained using 24‐h dynamic ECG. Analysis of the HRV in the time domain showed a longer R‐R mean (medians; 871 ± 191 ms vs 758,5 ± 109,5 ms; P<0,05) in boys in the early adolescence group than similarly aged girls. Girls in the late adolescence exhibited significantly higher normalized low frequency (LFun; 84 ± 11% vs 70 ± 11%; P<0,05) and lower normalized high frequency (HFun; 16 ± 11% vs 30 ± 9%; P<0,05) versus boys in the same aged group. Girls in the early adolescence had significantly lower values for LFun (medians; 67 ± 19,6% vs 84 ± 11%; P<0,05) and higher values for HFun (medians; 33 ± 19,5% vs 16 ± 11%; P<0,05) as compared to girls in the late adolescence. No significant difference in LF/HF ratio was detected between both groups. There is an increase in LF power, an indicator of predominantly sympathetic activity, during pubertal development. These results indicate the need to account for gender‐ and age‐related differences in cardiac autonomic function measures.Supported by CAPES and FAEP/UNICAMP
Steric Gate Variants in a Y family DNA Polymerase Confer UV‐Hypersensitivity
Authors: Beuning Penny J , Shurtleff Brenna W , Sefcikova Jana , Walker Graham C 
Published: June 2021

Induction of the SOS response due to a cell's failed attempts to replicate damaged DNA results in the expression of at least 43 genes in E. coli. The induced genes include umuDC, whose products include the Y‐family DNA polymerase DNA pol V (UmuD′2C). E. coli UmuC is a DNA polymerase with the specialized ability to copy past lesions in the DNA template, but this activity may be mutagenic. Normal, replicative DNA polymerases have a “steric gate” residue that prevents incorporation of ribonucleotides in the nascent DNA, by serving as a steric block to the 2′‐OH. In the Y‐family polymerases, this residue appears important for facilitating lesion bypass activity. We have found that steric gate mutants of UmuC cause extreme cellular sensitivity to UV exposure and are dominant negative at low copy number. Mutations in the known beta clamp binding motifs of UmuC or deletion of the proofreading subunit of DNA pol III suppress the UV hypersensitivity of the steric gate variant. We have found that mutation of residues surrounding the steric gate result in decreased mutagenesis without cellular hypersensitivity to UV light.Supported by a Dreyfus Foundation New Faculty Award.
Differences in electrogenic secretion of electrolytes in colonic epithelium of inbred mouse strains.
Authors: Flores Carlos A , Sepulveda Francisco V , Cid L Pablo 
Published: June 2021

The mouse is the animal model of choice in studies of the physiology and pathophysiology of intestinal fluid and electrolyte transport. In the course of our research in colon physiology we have observed differences in electrical tissue properties and responses to agonists that induce electrogenic secretion of electrolytes among mice strains. Such differences are important enough to preclude comparisons between strains and might be crucial when choosing the genetic background for knockout of genes of interest. We have now investigated some of these differences by electrophysiological methods. Colonic tissue from Black Swiss, 129Sv and B6 mice were placed in Ussing chambers and their responses to a series of agonists and blockers recorded. We observe that while the 3 strains have similar anion secretory responses to increasing cAMP (around ‐100 μA cm−2), when the muscarinic agonist carbachol was used the largest response was seen with B6 tissue, compared to that of Black Swiss and 129Sv colon (‐200, ‐163 and ‐133 μA cm−2 respectively). The importance of the genetic background on the severity of cystic fibrosis in mice has long been known (Rozmahel et al., Nat Genet 12: 280‐7, 1996) and has been related to differences in calcium‐dependent anion secretion. We reported previously that basolateral KCNN4 calcium‐activated potassium channels are the rate‐limiting step in calcium‐agonist‐dependent anion secretion, rather than apical CFTR chloride channels (Flores et al., J Physiol 583: 705‐17, 2007). We are studying KCNN4 expression as a possible explanation to these differences.Supported by FONDECYT 3085023
LPS and hypoxia alters the production/release of catecholamines in Immortalized Human Mesangial Cell
Authors: Zanini Ana Paula , Arita Danielle Yuri , Almeida Waldemar Silva , Casarini Dulce Elena 
Published: June 2021

Catecholamines (CA)‐dopamine (DA), L‐Dopa, epinephrine (EP) and norepinephrine‐are involved in filtration and renal vasoconstriction processes, and can be produced by mesangial cells (MC). MC expresses Toll Like Receptor 4, that detects lipopolysaccharide (LPS). LPS and hypoxia, both present in sepsis, can lead to acute renal failure. The aim was to asses the effect of LPS and hypoxia on the production/release of CA in immortalized human mesangial cell (IHMC). IHMC were cultured in DMEM and incubated with LPS (0.1, 1.0, 5.0 and 100 μg/mL) for 2 hours, or exposed to hypoxia for 30 min. CA were extracted from the medium and cell lysates was quantified by HPLC‐ED. Tyrosine hydroxylase (TH) expression ‐ step‐limiting enzyme ‐ was evaluated by Western blotting. LPS at 1 μg/mL induced a decline in intracellular L‐Dopa level as compared with control (5.3±1.6 vs.10.8±1.0 pg/mg protein). The concentration of 5 μg/mL decreased the intracellular level of L‐Dopa (4.9±1.3 vs. 10.3±1.0 pg/mg protein) and increased EP concentration (8.8±1.9 vs. 2.2±0.5 pg/mg protein). LPS at 100 μg/mL increased the levels of intracellular EP (102.7±8.4 vs.65.8±10.1 pg/mg), L‐Dopa (48.5±2.4 vs.22.2±4.1 pg/mg protein) and DA (24.9±2.9 vs.15.9±1.4 pg/mg protein) and decreased the concentration of EP (125.2±13.7 vs.205.4±10.4 pg/mg protein) and L‐Dopa (34.6±5.7 vs.57.4±8.6 pg/mg protein) in extracellular. TH expression was significantly affected by LPS (100 μg/ml), however it did not occurr under hypoxia condition. These results suggest that LPS can influence the production/release of CA in IHMC.Support by CNPq.
The Influence of Tungstate‐Exposure on Immunological Response to RSV Infection in C57BL/6 Mice
Authors: Fastje Cynthia Darlene , Harper Kevin , Park Yong Soo , Wong Simon S. , Witten Mark L. 
Published: June 2021

Significantly elevated concentrations of sodium tungstate have been demonstrated in the atmospheric particulate matter in multiple communities experiencing elevated rates of childhood leukemia, but not in their respective control communities. Prenatal exposure to sodium tungstate in C57BL/6 mice significantly decreased the transcriptome expression of Dmbt1, a protein which functions to aggregate bacteria and viruses in lung mucosa and saliva. Additionally, network analysis of gene microarray data produced a significant network associated with hematological/immunological disease focused on genes involved in viral defense. We hypothesize that exposure to sodium tungstate alters immunological and hematological response to viral infection as measured by qRT‐PCR of RSV genes F & G during the fastigium of the infection, CBC with a differential, and RT2‐PCR for genes associated with immunological function. C57BL/6 mice, exposed prenatally to sodium tungstate, demonstated a differential response to RSV viral infection. Additionally, tungsten exposure in male mice has a deleterious effect on testes function.Supported by EPA Grant EM‐96963201
Autonomic Dysregulation in a Mouse Model of Muscular Dystrophy Destined to Develop Dilated Cardiomyopathy
Authors: Sabharwal Rasna , Weiss Robert M , Chapleau Mark W 
Published: June 2021

Mutations in the dystrophin‐glycoprotein complex cause muscular dystrophy and dilated cardiomyopathy (DCM) in animals and humans. Mice deficient in sarcoglycan delta (Sgcd), a component of this complex, develop muscular dystrophy at a young age (<10 wks) with later onset of DCM (Cell 98:465‐474,1999). We hypothesized that autonomic dysregulation may occur early in the disease progression before development of DCM. We measured cardiac function (echocardiography); blood pressure (BP) and heart rate (HR) (telemetry); and indices of autonomic regulation including baroreflex sensitivity (BRS) and HR variability (HRV‐SD) in 10‐12 wk old Sgcd‐/‐ and control C57BL/6 mice. Left ventricular ejection fraction (0.83±0.01 vs. 0.85±0.03) and end‐diastolic volume (26±2 vs. 33±4 µl) were normal in Sgcd‐/‐ mice. Histopathological features of muscular dystrophy were evident in skeletal muscle but not in the heart of Sgcd‐/‐ mice. Compared with control mice, Sgcd‐/‐ mice exhibited less locomotor activity (4±1 vs. 11±1 c/min), lower mean BP (100±2 vs.120±4 mmHg), and reductions in diurnal (night‐day) variability, BRS and HRV‐SD (see Table, *P<0.05).We conclude that young Sgcd‐/‐ mice exhibit decreased BP, loss of diurnal cardiovascular rhythms, and severe autonomic dysregulation prior to onset of cardiac dysfunction. We speculate that this early autonomic dysregulation may hasten the progression to DCM. (VA)
Sympatho‐inhibitory effect of atorvastatin due to anti‐senescence and attenuation of impaired neurogenesis in RVLM of SHRSP
Authors: Kishi Takuya , Hirooka Yoshitaka , Ito Koji , Araki Shuichiro , Konno Satomi , Sunagawa Kenji 
Published: June 2021

BackgroundNeural senescence in brain is progressed by reactive oxygen species (ROS), Ras‐caspase 3‐induced apoptosis and abnormal shortening telomere length, and is associated with neural function. Atorvastatin inhibits sympathetic nerve activity (SNA) by reduction of ROS in rostral ventrolateral medulla (RVLM) of stroke‐prone spontaneously hypertensive rats (SHRSP). Neurogenesis is reported to be impaired in RVLM of SHRSP. We hypothesized that atorvastatin inhibits SNA due to anti‐senescence and attenuation of impaired neurogenesis in RVLM of SHRSP.Methods and ResultsIn age‐matched control SHRSP (CNT), SNA, ROS, Ras activity, caspase‐3, p53 and p21 and neural senescence determined by β ‐galactosidase staining were significantly higher and telomere length was significantly shorter than in WKY (n=5 for each). In atorvastatin‐treated SHRSP (20 μg/kg/day, intracerebroventricular injection for 14 days, n=5) (ATORVA), SNA, ROS, Ras activity, caspase‐3, p53 and p21 and neural senescence were all inhibited and telomere length was significantly longer than in CNT. Neurogenesis in RVLM was significantly impaired in CNT than in WKY, and significantly improved in ATORVA than in CNT.ConclusionAtorvastatin attenuates neural cell senescence and impaired neurogenesis in RVLM of SHRSP, which contribute to sympatho‐inhibitory effect of atorvastatin.
Prenatal nicotine exposure exaggerates thermal prolongation of the laryngeal chemoreflex in rat pups
Authors: Xia Luxi , Leiter James C. , Bartlett Donald 
Published: June 2021

Laryngeal chemoreflex (LCR) apnea occurs in infants in response to water in the larynx and may contribute to pathogenesis of SIDS. The LCR is prolonged in neonatal piglets and rats that are warmed 1‐3 degrees C, and this thermal prolongation is exaggerated in rat pups born to mothers exposed to cigarette smoke during pregnancy. Since smoking mothers expose their fetuses to nicotine, we studied the effect on the LCR of combined prenatal nicotine exposure and brief postnatal hyperthermia in anesthetized rat pups. Pregnant rats were exposed to nicotine (6.4 mg/kg/day) or saline by infusion via implanted osmotic minipumps from gestational day 3 (GD3) until GD 21. The LCR was assessed between postnatal days 4‐15 with and without hyperthermia. Prenatal nicotine exposure exaggerated the thermal prolongation of the LCR. In the nicotine group (n=21), respiratory disruption by the LCR during hyperthermia averaged 13.24 1.85 sec, and the longest apnea averaged 8.29 1.29 sec. In the control group (n=24), respiratory disruption under the same conditions averaged 7.19 0.97 sec, and the longest apnea averaged 4.68 0.76 sec. Thus, prenatal nicotine exposure enhances the hyperthermic prolongation of the LCR, which has previously been shown in piglets to depend on GABAergic inhibition of breathing.(Supported by P01‐HD36379, HD042707 and a grant from the Flight Attendants Medical Research Institute.)