bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Aquaporin 5 gene polymorphism AQP5‐1364 A/C has no impact on loss of renal function in children following renal transplantation
Authors: Büscher Rainer , Adamzik Michael , Frey Ulrich , Nagel Dominik , Hoyer Peter F. 
Published: June 2021

Objectives:Aquaporins, a family of transmembrane water channels, are expressed in the kidney and are involved in chronic renal allograft dysfunction. A novel gain of function promotor polymorphism in the Aquaporin 5 gene (AQP5‐1364 A/C) has recently been demonstrated to alter AQP5 expression and might therefore contribute to water and salt homeostasis. We investigated whether the AQP5‐1364 A/C SNP is associated with loss of glomerular filtration rate (GFR, ml/min/1.73m2) and blood pressure in children following renal transplantation (RTx).Methods and Results:91 children (60 male, 31 female, mean age at RTx 9.6 years, mean follow up time 5.4 years) were included. The slope of GFR was determined by linear regression analysis. Allelic frequencies were not significantly different from healthy controls. However, homozygous C‐allele carriers were not detected in our study group. Loss of GFR and blood pressure were not different between the groups (AQP5‐1364 A/C: slope AA −0.02±0.17 vs. AC −0.22±0.17, p=0.454.Conclusion:The AQP5‐1364 A/C promotor polymorphism is not associated with the loss of renal function and blood pressure in children following RTx.
Lipoteichoic acid modulates hepatic drug metabolizing enzymes by activating the Toll‐like receptor 2 signaling pathway
Authors: Ghose Romi , Guo Tao 
Published: June 2021

Background:Altered expression of drug metabolizing enzymes (DMEs) in inflammation can affect the metabolism and toxicity of drugs. It is known that inflammatory responses are induced in immune cells by Lipopolysaccahride (LPS) and Lipoteichoic acid (LTA), derived from gram −ve and gram +ve bacteria, respectively. We reported that LPS modulates gene expression of hepatic DMEs and their regulatory nuclear receptors (NRs: PXR, CAR and RXRα) by activating Toll‐like receptor (TLR) 4 signaling pathway. We hypothesize that LTA can modulate NR and DME gene expression by activating the TLR2 signaling pathway. Methods: Adult male C57BL/6 mice were i.p. injected with 6 μg/g bw LTA or saline. Livers were harvested and RNA and proteins were analyzed by real‐time PCR and western blotting, respectively.Results:LTA treatment for 2h resulted in ∼80% suppression of CAR and target DME genes, Cyp2b10, Cyp2a4 and Sultn. The NR, PXR, and the main phase 1 DME, Cyp3a11 were reduced ∼70% by 4–8 h of LTA treatment. Nuclear protein levels of RXRα were reduced in LTA‐treated mice. LTA injection induced cytokine production and cell‐signaling components in the liver. The effects of LTA on NRs, DMEs, cytokines and cell‐signaling pathways were blocked in TLR2−/− mice, indicating that the effects of LTA on hepatic genes were mediated by TLR2.Conclusions:TLR2 is involved in regulating DME gene expression during induction of inflammation by LTA.
Continuous infusion of hyaluronidase reduces systemic glycocalyx volume and associates with increased molecular clearance
Authors: van den Berg Bernard , Meuwese Marijn Clara‐Maud , Stroes Erik Sjoerd Gerard , Vink Hans 
Published: June 2021

The endothelial glycocalyx shields the vascular wall from flowing blood and contributes to the permeability barrier.We hypothesized that continuous infusion of testicular hyaluronidase reduces the glycocalyx, resulting in increased clearance rates for large dextran molecules.C57Bl6 mice received 10, 25 or 100 U/hr hyaluronidase (intravenously, osmotic minipump) for 3, 7 or 14 days. Systemic glycocalyx volume (Vg) was estimated by tracer dilution using labeled red blood cells and 40kDa dextran. Clearance rate of 40kDa and 500kDa dextran were evaluated.Three days of hyaluronidase (100 U/hr) first increased Vg to 34.8±11.2 (SD) ml/kg, base‐line Vg 20.1±2.8 ml/kg. Continuation reduced Vg to 8.7±4.3 ml/kg (day 7) and 7.4±14.1 ml/kg at day 14 and was associated with increased clearance rates (min−1), from 0.023±0.002 and 0.0022±0.002 (day 0: 40‐ and 500kDa) to 0.044±0.016 and 0.020±0.005 (day 14: 40‐ and 500kDa). A dose dependent reduction in Vg was observed (day 14: 10.3±1.5 at 25 U/hr, 11.9±5.3 at 10 U/hr).We conclude that prolonged infusion of hyaluronidase eventually reduces systemic glycocalyx which in turn, results in a reduced permeability barrier.Supported by NHF 2005T037 to H. Vink and 2006B08 to E. Stroes
FRET assessment of CFTR molecular assembly
Authors: Berdiev Bakhrom K , Tousson Albert , Oosterveld‐Hut Henderika M.J. , Qadri Yawar J. , Cormet‐Boyaka Estelle , Hong Jeong S. , Fuller Cathy M. , Sorscher Eric J. , Lukacs Gergely L. , Benos Dale J. 
Published: June 2021

In spite of extensive studies, uncertainty exists regarding the number of CFTR molecules that come together to form a conducting pore. At present, findings point both to monomeric and multimeric assembly of CFTR protein. We evaluated the CFTR assembly by fluorescence resonance energy transfer imaging. FRET exploits the exquisite sensitivity of fluorescence measurements to detect molecular complexes with near angstrom resolution. We assayed for FRET between (i) N‐terminally tagged CFTRs (ECFP‐CFTR and EYFP‐CFTR); (ii) C‐terminally tagged CFTRs (CFTR‐ECFP and CFTR‐EYFP); and (iii) both N‐terminally and C‐terminally tagged CFTRs (ECFP‐CFTR and CFTR‐EYFP). We found no appreciable increase in CFP fluorescence after selective photobleaching of YFP, indicative of no FRET occurrence. Our findings show that the cytoplasmic tails of CFTR are not in sufficient proximity for the occurrence of FRET, suggestive of monomeric organization of CFTR.Supported by NIH 2RO1‐DK37206‐15, NIH P50 DK53090‐05, NIH RO1‐DK075302, CFF/CFFT.
Endothelin‐1‐induced NOS3 activation is mediated by the PI3K/AKT pathway in the thick ascending limb
Authors: Herrera Marcela , Garvin Jeffrey L. 
Published: June 2021

Endothelin‐1 (ET‐1) inhibits NaCl transport by the thick ascending limb (THAL) via increased NO. NOS3 is the primary source of NO in this segment. Phosphorylation of NOS3 at serine 1177 (pNOS3 Ser1177) positively regulates its activity. We hypothesized that ET‐1 stimulates pNOS3 Ser1177 via activation of the PI3K/AKT pathway. We measured: 1) pNOS3 Ser1177 by Western blot; 2) AKT activity using a FRET‐based AKT reporter; and 3) pAKT Ser473. Rat THALs were treated with ET‐1 (1nM) for 15 min. ET‐1 increased pNOS3 Ser1177 by 45 ± 9 % vs. control (p = 0.001; n = 6). Wortmannin (wort., 150nM), a PI3K inhibitor, blocked this effect (Δ + 3 ± 14 % vs. wort. alone, n = 5). The AKT reporter was expressed in the THAL by in vivo gene transfer. The probe is a fusion protein of the AKT consensus phosphorylation site, CFP and YFP (Kunkel et al, JBC. 280(7):5581–7). An increase in the CFP/YFP ratio indicates increased AKT activity. THALs were isolated and FRET measured by fluorescence microscopy. ET‐1 increased the CFP/YFP ratio by 0.16 ± 0.02 fluorescence units (f.u) (p < 0.01; n = 5). Wort. blocked this effect (Δ + 0.01 ± 0.01 f.u; n = 5). ET‐1 increased pAKT Ser473 by 47 ± 14% vs. control (p < 0.001; n = 5). Wort. blocked this effect (Δ + 2 ± 6 % vs. wort. alone). We concluded that ET‐1 acutely phosphorylates NOS3 at Ser1177 via PI3K/AKT activation in the THAL. This could be an important regulatory mechanism of THAL NaCl reabsorption by ET‐1.HL028982, HL070985
Functional Characterization of Pufferfish Slc26a6A and Slc26a6B
Authors: Kato Akira , Chang Min‐Hwang , Kurita Yukihiro , Nakada Tsutomu , Hirose Shigehisa , Romero Michael F. 
Published: June 2021

Euryhaline pufferfish (Takifugu obscurus, mefugu) can live in freshwater (FW) with ion concentration less than 1/100 of its body fluid or acclimate to seawater (SW) which has more than 3 times the ion concentration of its body fluid. However, the body‐fluid ion concentrations are maintained stable by the function of epithelial cells in the gill, intestine, and kidney which transport ions directionally and selectively. To understand the mechanisms of the fish body‐fluid homeostasis at the molecular level, there are several essentials: identification of transporters expressed in the epithelia, determination of transporter localization, and characterization of transporter activities. Analyses of various transporter mRNA levels in mefugu tissues identified increases for Slc26a6A and Slc26a6B in the intestine and the kidney of SW‐acclimated mefugu. To study their functions for SW acclimation, we subcloned the cDNAs into a Xenopus expression vector and assayed their functions using microelectrodes in oocytes.The electrophysiological analyses of the oocytes revealed that (a) Slc26a6A and Slc26a6B are electrogenic Cl−/nHCO3− exchangers; (b) Slc26a6A and Slc26a6B are also exchangers of Cl−/formate, Cl−/oxalate, and Cl−/SO42−; and (c) the slope of I–V relationship of Slc26a6A in the presence of SO42− is 70 times higher than that of Slc26a6B. These results suggest significant roles for Slc26a6A and Slc26a6B in intestinal HCO3− secretion and a role for Slc26a6A in renal SO42− excretion during SW acclimation.This work was supported by MEXT Japan, NIH (EY017732) and CFF grant (Romero‐06G0).
TRPM3 channel expression and block in vascular smooth muscle cells
Authors: Naylor Jacqueline , Li Jing , Milligan Carol J , Zeng Fanning , Porter Karen E , Beech David J 
Published: June 2021

TRPM3 is a calcium‐permeable channel activated by sphingolipids, including D‐erythro‐sphingosine (Grimm et al 2005, Mol Pharmacol 67, 798–805). Its cellular functions are largely unknown. Using methods to develop isoform‐specific channel blockers (Xu et al 2005, Nat Biotechnol 23, 1289–93) we produced a TRPM3‐specific blocking agent (TM3E3). Preincubation of cells with TM3E3 produced about 40% block of TRPM3‐mediated calcium‐entry or ionic current. TM3E3 had no effect on the closely related channel TRPM2, or other TRP family members TRPC5 and TRPV4, confirming its specificity for TRPM3. Recently, novel activators for TRPM3 have been suggested. In conjunction with TM3E3, these activators have been used to study a potential role of TRPM3 in human vascular smooth muscle cells. The cells express mRNA encoding TRPM3 and the presence of TRPM3 is indicated by labelling with anti‐TRPM3 antibodies. Sphingosine and its analogues evoked calcium responses that could be inhibited by gadolinium, 2‐APB, TM3E3 or siRNA targeting TRPM3. The data suggest TRPM3 is a novel calcium‐entry channel of vascular smooth muscle cells.The research was supported by a BBSRC Industrial Co‐operative Award in Science and Engineering, the Wellcome Trust and the British Heart Foundation.
Electrolyzed water reduces urinary protein excretion in the streptozotocin induced diabetic Dahl salt sensitive rats
Authors: Ohsaki Yusuke , Mori Takefumi , Yoneki Yoshimi , Endo Satoshi , Hosoya Takuma , Zhu Wanjun , Nakayama Masaaki , Ito Sadayoshi 
Published: June 2021

Background: Electrolyzed water generated at the cathode side (EW) has been shown to have anti‐oxidative properties. Present study was designed to investigate the anti‐oxidative and renal protective effect of EW in the progression of renal injury in streptozotocin induced diabetic Dahl salt sensitive rats.Methods: Four weeks old male Dahl salt sensitive rats were given either tap water (Tap) or EW for 15 weeks. Streptozotocin was administered (65mg/kg intraperitoneally) at 6th week, and rats were assigned to two groups by the blood glucose (BG) level below (STZ‐) and above (STZ+) 300 mg/dL. Plasma biological antioxidant potential (BAP) level was assayed. Urine samples were collected in a metabolic cage.Results: Urinary protein excretion largely increased in STZ+ group and reached to 516±56mg/day at end of study compared to those of 256±19mg/day in STZ‐ group. EW significantly attenuated the increase in urinary protein excretion at level of 375±65mg/day at the end of the study. Plasma BAP level was significantly reduced in STZ+ group while no reduction of was observed in STZ‐ group. EW abolished the reduction of BAP in STZ+ group.Conclusion: The results in the present study indicate that EW could reduce renal injury by increasing plasma anti‐oxidative activity in streptozotocin induced diabetic Dahl salt sensitive rats.
Obesity Increases Renal Cortical Neovascularization in Zucker Rats
Authors: Iliescu Radu , Reckelhoff Jane F , Chade Alejandro R. 
Published: June 2021

Growing evidence supports the role of obesity as an independent risk factor for chronic kidney disease. Obesity promotes inflammation. Inflammatory cytokines can induce neovascularization in different organs, including the kidneys. However, whether obesity triggers renal neovascularization and, if so, the physiological significance has never been investigated.Renal microvascular architecture was studied by 3D micro‐computer tomography in lean and obese Zucker rats (LZR and OZR, n=6/group). Mean arterial pressure (MAP), renal blood flow (RBF), and proteinuria were measured in vivo. Systemic inflammation was assessed by measuring levels of interleukin (IL)‐6 and tumornecrosis‐factor (TNF)‐α. In addition, renal histology was studied in cross sections stained with trichrome.Renal microvascular density was significantly elevated in OZR (Figure). Despite mild proteinuria and increased tubulo‐interstitial and glomerular damage in OZR, RBF and MAP were similar in both groups (Figure). Furthermore, OZR showed a substantial elevation in systemic IL‐6 and TNF‐α (3–4 fold), suggesting increased inflammation.The current study shows for the first time increased renal cortical vascularization in an animal model of obesity, which possibly reflects a compensatory mechanism that sustains RBF. However, increased inflammation in obese rats may promote further renal injury, as has been observed in obese humans, as the disease progresses.(Supported by HL‐69194 and Intramural Research Grant Support from the University of Mississippi)
Exercise training normalizes ACE and ACE2 in the brain of rabbits with pacing induced chronic heart failure
Authors: Kar Sumit , Gao Lie , Zucker Irving H 
Published: June 2021

Activation of the renin‐angiotensin system (RAS) in the brain plays a critical role in sympatho‐excitation of chronic heart failure (CHF). Exercise training (EX) normalizes sympathetic outflow. The mechanisms that regulate angiotensin converting enzyme (ACE) in the brain and the effect of EX on ACE are unknown. The aim of this study was to investigate the regulation of ACE and ACE2, a homologue of ACE, in various areas of the brain with a pacing CHF‐EX model. Experiments were performed on four groups of New Zealand White rabbits: sham, sham + EX, CHF, and CHF + EX (n=5/group). Punches of the PVN, NTS, and RVLM (n=2/group) were also measured. Western blot analysis and double immunofluoresence were performed to measure and localize expression of ACE and ACE2. ACE expression in the cerebellum, medulla, and hypothalamus was significantly higher in CHF rabbits compared to sham (1.0±0.2 to 2.2±0.1 in the hypothalamus, P<0.05). EX normalized this upregulation compared to CHF (0.5±0.1 to 2.2±0.1 in the hypothalamus). ACE2 was significantly decreased in CHF. EX normalized ACE2 in the PVN, NTS, and RVLM (0.03±0.02 CHF to 0.8±0.3 CHF + EX in the RVLM). ACE was present in both endothelial cells and neurons. The results suggest that EX normalizes ACE and ACE2 in sympatho‐regulatory areas.Source of support: PO‐1 HL62222
Contrasting Autonomic and Cardiovascular Phenotypes in ASIC1a and ASIC2 deficient mice
Authors: Sabharwal Rasna , Wemmie John A , Abboud Francois M , Chapleau Mark W 
Published: June 2021

Members of the acid‐sensing ion channel (ASIC) family are differentially expressed in subpopulations of sensory and central neurons and have been implicated in a variety of neuronal functions. We recently demonstrated that mice deficient in ASIC2, a subunit implicated in mechanotransduction, exhibit baroreflex and autonomic dysfunction, and hypertension (FASEB J 20:2006). The goals of the present study were to characterize autonomic and cardiovascular phenotypes in conscious ASIC1a−/− mice and compare the results to those obtained in ASIC2−/− mice. Arterial blood pressure (BP), heart rate (HR), and locomotor activity were measured by radio‐telemetry (DSI) in the mouse home cage. Mean BP and HR (24 hr avg.), cardiac sympathetic tone (HR response to propranolol), and sympathetic vasomotor tone (BP response to ganglionic blocker chlorisondamine) were all significantly higher in ASIC2−/− (n=5–7), but not different in ASIC1a−/− (n=7) vs. wild‐type (WT, n=7) mice (Table, *P<0.05).In contrast to the cardiovascular and autonomic phenotypes, locomotor activity was decreased in both ASIC1a−/− and ASIC2−/− mice compared with WT. We conclude: 1) ASIC1a does not contribute to baseline BP, HR, or sympathetic tone under resting conditions in conscious mice, 2) ASIC2 exerts a powerful restraining influence on sympathetic activity and BP, and 3) the ASIC2−/− mouse is a model of chronic neurogenic hypertension. (AHA 0725771Z, HL14388)
Pressure Dependence of Compression‐Induced Dilation
Authors: Jasperse Jeffrey L. , Clifford Philip S. 
Published: June 2021

We have recently demonstrated that mechanical compression causes dilation of soleus feed arteries. The current study examined the pressure dependence of compression induced dilation. We hypothesized that the magnitude of dilation would be directly related to the compression pressure. Rat soleus feed arteries (n=10) were isolated, cannulated, mounted on micropipettes in a sealed vessel chamber, and pressurized to 68 mmHg. Luminal diameter was measured using an inverted microscope. An electronically controlled solenoid valve system permitted delivery of accurately timed pulses of extravascular pressure at 68, 100, 300, or 600 mmHg. Arteries dilated to single, 1‐sec pressure pulses at each pressure and the dilation was similar at all compression pressures (15±2%, 16±2%, 17±2%, and 18±2% dilation respectively). Multiple pressure pulses (30 1‐sec pulses with 1‐sec intervals) produced dilations of 27±3%, 40±5%, 46±6%, and 44±6% dilation respectively (p<0.05). These data indicate that the dilation to single compressions is not dependent on compression pressure. The dilation to multiple compressions is related to compression pressure, but plateaus at pressures above 300 mmHg. Since the arteries dilated to pressures within the range of those observed during locomotory exercise, we conclude that compression induced dilation could contribute to the rapid hyperemia observed at the onset of exercise.Supported by Seaver Research Council and the National Heart, Lung, and Blood Institute
Contribution of intramuscular TG and plasma FFA to the long chain acyl‐carnitine pool: effects of insulin in trained and untrained humans
Authors: Kanaley Jill , Sheehan Michael , Guo ZengKui , Jensen Michael D 
Published: June 2021

This study examined the plasma FFA, intramuscular long chain acylcarnitine (LCAC) fatty acids and imTG stores during basal and hyperinsulinemic conditions.Methods:Endurance trained (TR, n=8) and sedentary individuals (SED, n=15) were studied under overnight postabsorptive and euglycemic hyperinsulinemic clamp (1.0mU·kg FFM−1·min−1) conditions. FFA kinetics were measured using a 5‐h infusion of [U‐13C]oleate, for labeling of imTG and LCAC pools. Muscle biopsies were performed to measure imTG and imLCAC enrichment at 1400 h after 5‐h of infusion.imTG concentrations were greater in TR than SED individuals (P<0.01).Table

SED
Trained

Saline**
Clamp
Saline**
Clamp

plasma oleate FFA (mpe)
0.210±0.018*
0.271±0.036*
0.189±0.026*
0.361±0.050*

imLCAC (mpe)
0.025±0.003
0.005±0.002
0.016±0.005
0.002±0.002

imTG (mpe)
0.018±0.003†
0.011±0.001†
0.024±0.004†
0.013±0.001†

P<0.001 saline vs. clamp; *P<0.000 between compartment (plasma vs. imLCAC vs. imTG); †P<0.000 imLCAC and imTG

Methods:Endurance trained (TR, n=8) and sedentary individuals (SED, n=15) were studied under overnight postabsorptive and euglycemic hyperinsulinemic clamp (1.0mU·kg FFM−1·min−1) conditions. FFA kinetics were measured using a 5‐h infusion of [U‐13C]oleate, for labeling of imTG and LCAC pools. Muscle biopsies were performed to measure imTG and imLCAC enrichment at 1400 h after 5‐h of infusion.Conclusion:The imTG contributes more to the imLCAC pools than plasma FFA both in the basal and hyperinsulinemic state, and hyperinsulinemia suppressed oleate FFA entry into the imLCAC pools, more so in trained than untrained adults. Muscle fatty acid oxidation is largely via obligatory cycling of fatty acids through imTG or other intracellular complex lipid pools.
Mild cold and overfeeding adaptive thermogenesis: role of mitochondrial uncoupling
Authors: Wijers Sander L.J. , Schrauwen Patrick , Saris Wim H.M. , van Marken Lichtenbelt Wouter D 
Published: June 2021

Mild cold exposure and overfeeding are known to elevate energy expenditure, so‐called adaptive thermogenesis. In adult humans, mitochondrial uncoupling in skeletal muscle tissue is a candidate mechanism.We aim to investigate whether diet induced and cold induced adaptive thermogenesis in humans are related to mitochondrial uncoupling in skeletal muscle tissue. The metabolic response to mild cold and overfeeding in 13 lean adult male subjects was measured in a respiration chamber in a baseline condition, after three days of mild cold exposure, and after three days of overfeeding. After each respiration chamber measurement a muscle biopsy was taken, in which mitochondrial uncoupling was measured by high‐resolution respirometry. The uncoupling ratio was defined as state 4 respiration (substrates + ADP + ATP‐synthase blocker) divided by state 3 respiration (substrates + ADP).Total daily energy expenditure increased after overfeeding with 6.9% (0.79 MJ/day) and after mild cold exposure with 5.7% (0.65 MJ/day). Uncoupling ratio increased with respectively 58 and 24%. Uncoupling ratio correlated significantly with total daily energy expenditure (R2=0.533, p=0.01).This study for the first time shows that skeletal muscle has the intrinsic capacity for adaptive thermogenesis in humans via mitochondrial uncoupling.
Doxorubicin stimulates oxidant activity, weakness and fatigue in murine skeletal muscle
Authors: Ashley Laura A. , Ferreira Leonardo F. , Smith Jeff D. , Hardin Brian J. , Noel Teresa J. , St. Clair Daret K. , Reid Michael B. 
Published: June 2021

Doxorubicin is the most commonly prescribed chemotherapeutic agent. Doxorubicin causes an increase in free radical production in the myocardium and cardiac muscle dysfunction. Patients receiving chemotherapy also experience weakness and fatigue leading us to hypothesize doxorubicin (1) increases muscle‐derived oxidants and (2) depresses diaphragm and limb muscle force in mice. Doxorubicin treatment (20μM, 1hr) in vitro increased oxidant activity in diaphragm muscle as measured using DCF fluorescence (n=3, p<0.04). We injected C57B6 male mice intraperitoneally with doxorubicin (20 mg/kg), a cumulative dose commonly used in cardiotoxicity studies. Diaphragm and extensor digitorum longus (EDL) were excised three days post injection, compared to controls, doxorubicin lowered maximal force in diaphragm by 62.2 ± 7.1% (mean ± SE; n=5, p<0.01) and EDL by 28.7 ± 7.9% (n=3, p<0.03). Doxorubicin depressed diaphragm twitch characteristics, including peak force (−37.7 ± 12.5%; n=5, p<0.01) and time to peak force (Doxorubicin 0.15 ± 0.02 N s−1, Control 0.29 ± 0.02 N s−1). At the end of the fatigue trial, force was lower in doxorubicin treated mice 26.9 ± 12.2% of control values. The stability of the muscle in vitro was not altered. Our data shows that doxorubicin causes skeletal muscle weakness and predisposes muscle to fatigue, which may be due to an increase in muscle‐derived oxidants.Supported by: HL 59878 (MBR)