bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Role for CHAC1 in Acetaminophen Hepatotoxicity
Authors: Crawford Rebecca , Rowe Josef , Prescott Eugenia , Mungrue Imran 
Published: June 2021

Acetaminophen (APAP) is a commonly used pain reliever and a well‐established, dose‐related hepatotoxin. Hepatotoxicity occurs when metabolism of excessive APAP generates high concentrations of the reactive metabolite N‐acetyl‐p‐benzoquinone imine (NAPQI). NAPQI depletes cellular glutathione (GSH) and forms protein adducts leading to cellular stress, mitochondrial dysfunction, and, ultimately, oncotic necrosis of Zone 3 hepatocytes. The endoplasmic reticulum (ER) stress pathway is important to maintain cellular protein folding abilities in times of stress. However, extended or aberrant ER stress signaling can lead to apoptosis through the PERK‐ATF4‐CHOP pathway. Our research explores the regulation and contribution of CHAC1, an enzyme within this pathway, in response to APAP overdose.As purified mouse and yeast CHAC1 was shown to degrade GSH, the consequences of CHAC1 overexpression on GSH levels in human liver was explored in a human hepatoma cell line (HepG2). Overexpression of CHAC1 by transient transfection leads to a ~50% reduction in total GSH levels. As depletion of GSH is an important step in the pathology of APAP hepatotoxicity, the expression of CHAC1 mRNA in HepG2 cells was examined following 24‐hour treatment with 30mM APAP. CHAC1 mRNA was induced five‐fold by APAP, along with other components of the PERK‐ATF4‐CHOP pathway. Interestingly, overexpression of CHAC1 in HepG2 cells treated with APAP led to increased toxicity versus APAP alone, implicating a role for CHAC1 in response to APAP. Overall, these data implicate a new role for CHAC1 in the pathology of drug‐induced liver injury.
Genetic Depletion of T cell S1P Receptor 1 Exhibits Improved Cardiac Function and Less Fibrosis in Streptozotocin‐Induced Type 1 Diabetic Mice
Authors: Abdullah Chowdhury , Wang Xiuqing , Jin Zhuqiu 
Published: June 2021

IntroductionT lymphocyte infiltration into myocardium has been observed in patients with diabetes. Sphingosine 1‐phosphate 1 (S1P1) regulates mature T cells egress from lymphoid organ to blood and peripheral organs. The role of T lymphocytes in diabetic hearts remained elusive. Methods and Results: Depletion of T cell S1P1 receptors was attained by breeding of S1P1loxP/loxP mice with Lck‐driven Cre transgenic mice. T cell‐specific S1P1 receptor knock‐out mice (TCS1P1KO) and littlemate wild‐type mice (WT) were divided into vehicle control and streptozotocin (STZ) groups. Type 1 diabetes was induced by five days injection (i.p.) of STZ at a dose of 50 mg/kg. Control mice were injected buffer only. Body weight and fasting blood glucose level was measured at the beginning, 4, and 11 weeks. Mature CD4 and CD8 T cells in blood as well as regulatory T cells (Tregs) and Th17 cell in both spleen and blood were counted by flow cytometry. Masson's Trichrome staining was conducted to assess fibrosis. Cardiac contractile force was measured by Langendorff perfusion at the end of 11 weeks. TCS1P1KO mice had reduced CD4 T cells (1.15+/‐0.30% vs 25.06+/‐0.64% in WT, P<0.01, n=4‐5 per group) and CD8 T cells (2.09+/‐042% vs 14.72+/‐038% in WT, P<0.01) in blood. Treg cells increased in blood in WT STZ mice (1.75+/‐0.20% vs 0.39+/‐0.18% in KO STZ mice). TCS1P1KO STZ mice exhibited less cardiac fibrosis and enhanced cardiac contractile force compared to WT STZ mice.ConclusionSelective depletion of T cell S1P1 reduces mature T lymphocytes in circulation and exerts improved cardiac function and less myocardial fibrosis in diabetic hearts.
Evaluation of newly developed histone deacetylase inhibitors for the treatment of solid tumors
Authors: Steinemann Karl Gustav , Nitzsche Bianca , Hoffmann Björn , Kuzyniak Weronika , Pries Axel , Hoepfner Michael 
Published: June 2021

The inhibition of histone deacetylases (HDACs) with small‐molecule inhibitors is a new and promising approach for innovative cancer treatment. Histones are of importance for the organization of DNA in the form of chromatin. Transcriptional regulation comprises of a complex machinery of histone modifications, DNA‐methylation as well as acetylation and deacetylation of the chromatin. Dysregulation of acetylation and deacetylation of histones plays an important role in the development and progression of cancer and is often associated with an overexpression or upregulated activity of HDACs. HDAC inhibitors (HDACi) are highly versatile, and have effects on cell cycle, DNA‐repair, DNA‐damage, mitosis, apoptosis and angiogenesis. Here we investigated the suitability of newly synthesized HDACi with enhanced antitumor efficacy as compared to the already established HDACi, such as SAHA.Studies on a set of different cancer cell models (urological cancer cells with or without cisplatin resistance, neuroendocrine gastrointestinal tumor cells and esophageal cancer cells) revealed pronounced growth inhibitory and apoptosis‐inducing effects – starting at nanomolar concentrations (180nM – 1.6µM). Moreover, in vivo tests using the CAM assay method revealed antiangiogenic effects and a concomitant reduction of tumor growth of inoculated urological tumors. Further investigations will focus on the underlying mode of action of the new HDACi in terms of apoptosis, attenuation of subtype‐specific HDAC‐activity and cell cycle regulation.
ROLE OF HSP72 IN THE CARDIAC REMODELING INDUCED BY HIGH FAT DIET
Authors: Moreira Luana , Guedes Elaine , Leal Tábata , Mestril Ruben , Miyabara Elen , Diniz Gabriela 
Published: June 2021

IntroductionPrevious study demonstrated that HSP72 protects against obesity‐induced insulin resistance. However, the potential role of HSP72 in the cardiac remodeling induced by high fat (HF) diet remains unknown.ObjectiveThe aim of this study is to investigate the role of HSP72 in the cardiac remodeling induced by HF diet.MethodsMale wild‐type (WT) and HSP72 transgenic (HSP72 Tg) mice were fed a normal diet or a HF diet for 10 weeks. Body weight was monitored weekly. Fasting glucose levels were measured and intraperitoneal glucose tolerance test (iGTT) was performed. Systolic blood pressure (SBP) was evaluated by tail‐cuff plethysmograph. Western Blot was used to evaluate the cardiac HSP72 and HSP90 levels. Cardiac hypertrophy will be determined by heart weight normalized by tibia length. Histological analysis will be performed to evaluate the cardiomyocyte diameter and the interstitial fibrosis.ResultsHF diet increased the body weight and the fasting glucose levels in WT mice. However, HSP72 Tg were resistant to HF diet‐induced increase in body weight.In addition, HF diet induced glucose intolerance in WT mice. HF diet did not change the SBP in WT mice. The cardiac HSP70 levels were increased in HSP72 Tg when compared to those observed in WT mice. On the other hand, cardiac HSP90 levels were similar between WT and HSP72 Tg mice.ConclusionsThese results demonstrate that HF diet increases the body weight and fasting glucose levels, as well as induces glucose intolerance in WT mice. In addition, cardiac HSP70 levels were increased on HSP72 Tg mice, supporting the use of these mice to investigate a potential role of HSP72 in the cardiac remodeling induced by HF diet.
Wnt3a and Wnt1 Enhance Myogenesis of C2C12 Myoblasts – Potential Mechanisms of Osteocyte to Muscle Cell Signaling
Authors: Huang Jian , Mo Chenglin , Bonewald Lynda , Brotto Marco 
Published: June 2021

We have proposed that muscle and bone communicate via biochemical factors that are reciprocally important for optimal function. WNTs are secreted by osteocytes and have a significant potential to directly influence muscle function. We showed that WNT3a enhanced myogenic differentiation at a concentration of as low as 0.5ng/ml, and stimulated β‐catenin translocation to the nucleus of C2C12 muscle cells. Now, we show that Wnts express in MLO‐Y4 osteocytes and 2T3 osteoblasts, and their expression is dramatically enhanced by fluid flow shear stress, suggesting a physiological role with increased activity for example. WNT3a promoted overexpression of myogenic markers (MyoD, MyoG, MHC), and downstream genes of the β‐catenin pathway (Fhl1 and Numb). Furthermore, WNT3a treated C2C12 cells demonstrated higher expression of Axin2, Wnt5a, Gata3 and Adm, while the expression of Hey2, Ifng, Icam1, Tnf and Lrg1 decreased significantly. These genes represent the Wnt signaling pathway (Axin2, Wnt5a), JAK1, 3/Stat6 signaling pathway (Gata3), Hypoxia signaling pathway (Adm), Notch signaling pathway (Hey2), NFκB signaling pathway (Tnf, Ifng, Icam1) and the Stat3 signaling pathway (Lrg1). These results suggest that WNT3a may function through these pathways to regulate C2C12 myoblast differentiation.Support: NIH‐NIA P01 AG039355 (LB, MB), and the Dale and Dorothy Thompson Endowment Fund (MB).
Effects of arginine vasopressin (AVP) deficiency on basal mean arterial blood pressure in the rat
Authors: Villanueva Gloria , Organista‐Esparza Alejandro , Viñuela‐Berni Verónica , Huerta‐Carreón Erika , Chavira‐Ramirez Roberto , Tinajero‐Ruelas Manuel , Kovacs Kalman , Quintanar‐Stephano Andrés 
Published: June 2021

The role of AVP controlling the mean arterial blood pressure (MBP) in basal conditions remains unclear. We described that neurointermediate pituitary lobectomy (NIL) in rats, induced an early but transient diabetes insipidus and low MBP (8 weeks after lobectomy). To elucidate the chronological effects of NIL, we evaluated the AVP serum levels, water intake and urine output (diabetes insipidus, DI), and MBP immediately (0 to 6 hours post NIL) and 3, 15, 45 and 90 days post NIL. The renin, angiotensin II and aldosterone system (RAAS) was assessed at 3 and 45 days post NIL. Values were compared with the respective SHAM operated groups. Results: NIL caused significant and permanent AVP serum level decrease (10.6 ± 0.8 vs 2.4 ± 0.16 pg/ml (SD), SHAM vs NIL), transient DI (15‐30 days of duration) and permanent decrease of the MBP in 70% of the NIL animals (106.8 ± 3.15 vs 73.8 ± 3.2 mmHg). Hypotension was apparent 20‐30 minutes after NIL. No significant differences in the RAAS were evident.ConclusionsWe propose that in non‐stressed animals, basal serum levels of AVP are required to maintain the hydro‐electrolytic balance and MBP. Further studies are needed to explain why some animals did not develop hypotension, and to determine how cardiovascular, renal and hormone adaptive mechanisms in the NIL group support their survival.Supported by UAA‐PIFF and CONACYT, México and the Jarislowsky and L. Carr‐Harris Foundations
P Wave Indices on Electrocardiogram and their Association with Obesity and Metabolic Syndrome
Authors: Vaidean Georgeta , Manczuk Marta , Vansal Sandeep 
Published: June 2021

IntroductionThe obesity and atrial fibrillation epidemics may be linked. Obesity is a risk factor for atrial fibrillation but whether alterations of the P wave indices are associated with obesity is not fully understood.MethodsWe used cross‐sectional data of 11792 men and women, ages 45 to 64 years, in the PONS cohort in Poland. Data were collected via standardized questionnaires, physical exam and fasting blood samples. The P wave duration and PR interval were recorded on a 12‐lead standard ECG. Lack of sinus rhythm, third degree heart block and PR intervals <= 80ms or >=320 ms were excluded.ResultsThere were 3893 men (33.01%) and 7899 women with a mean age of 55.67 years (SD 5.37). The mean (SD) for the P wave duration and PR interval were 106.86 ms (16.44) and 156.37 ms (24.52) respectively. For both indices, there were progressive increases from the lowest (< 25 kg/m2) to the highest (> 30 kg/m2) BMI quartile (p for linear trend < 0.0001), after adjusting for age, gender, smoking , heart rate and heart disease. A trend was observed with increasing number of metabolic syndrome components. There was a positive association between the adjusted P wave duration and blood pressure control: SBP/DBP <120/80 : 104.85 ms (95% CI 103.98‐105.72); SBP 120‐140/DBP 80‐90: 106.79ms (106.42‐107.16); SBP/DBP> 140/90: 107.93 ms (95% CI 107.35‐108.51).ConclusionP wave indices were significantly associated with obesity, metabolic syndrome and level of blood pressure control; they may represent markers of atrial fibrillation in individuals with obesity and/or metabolic syndrome.
oxLDL induce endothelial cell stiffening through Rho/ROCK signaling pathway
Authors: Zhang Chongxu , Oh Myung‐Jin , Levitan Irena 
Published: June 2021

Our lab demonstrated that Oxidized LDL (OxLDL) induce endothelial cell stiffening. The signal transduction pathways leading to this increase in stiffness remain poorly understood. We hypothesize that the Rho/ROCK pathway plays a role in oxLDL induced endothelial cell stiffening. To test our hypothesis, human aortic endothelial cells (HAEC) were treated with 50µg/ml oxLDL and Rho/ROCK signaling was probed by western‐blot. First, our results show that RhoA is significantly activated by 50ug/ml oxLDL stimulation. The activated RhoA level increased 1.9 times vs control after 15 minutes incubation with oxLDL, and activated RhoA level return to control level after 60 minutes of incubation with oxLDL. Second, incubation with oxLDL increase phospho‐myosin phosphatase target subunit 1 (p‐MYPT1 (Thr853)) and phosphor‐Myosin ligh chain 2 (p‐MLC2 (Thr18/Ser19) expression level vs control. We further test that if oxLDL could affect myosin phosphorylation. Our data showed p‐MLC2 increased 1.7 times vs control after 15 minutes incubation with oxLDL, and increased 2.6 times vs control after 60 minutes incubation. The level of p‐MYPT1, which indicate the inhibition of myosin phosphatase, increased to 1.7 times vs control after 15 minutes incubation with oxLDL. Third, to further test our hypothesis, we treated HAECs with RhoA inhibitor (C3) or ROCK inhibitor (Y27632) before oxLDL incubation. Our data showed that both C3 and Y27632 attenuate oxLDL induced increase of p‐MLC2 and p‐MYPT1. Lastly, our data showed that increase of cell stiffening is also attenuated by C3 or Y27632 when treated with oxLDL.ConclusionoxLDL induce cell stiffening through increase RhoA activity, active Rho/ROCK pathway, inhibition myosin phosphatase, thereby increasing phosphorylation of myosin and leading to cell stiffening.
The Role of AMPK‐SIRT1 Pathway in High Glucose‐Induced Insulin Resistance in Rat Cultured Podocytes
Authors: Rogacka Dorota , Piwkowska Agnieszka , Audzeyenka Irena , Angielski Stefan , Jankowski Maciej 
Published: June 2021

Podocytes insulin sensitivity is critical for glomerular function and the loss of correct insulin signaling in consequence leads to alterations and disorders featuring diabetic nephropathy. The energy sensing pathways, like AMP‐dependent protein kinase (AMPK), and class III protein deacetylase SIRT1 have been shown to play an important role in insulin resistance.The aim of this study was determination of the role of AMPK and SIRT1 in insulin resistance of podocytes exposed to high glucose concentration. Experiments were performed in primary rat podocytes cultured with normal (NG, 11.1 mM) or high (HG, 30 mM) glucose concentrations for 5 days. Insulin‐stimulated changes in glucose uptake were used to detect insulin resistance.HG decreased the phosphorylation of AMPK by about 20% (P<0.05) and abolished insulin‐stimulated glucose uptake into podocytes. Knockdown of SIRT1 protein expression in NG‐cultured podocytes decreased AMPK phosphorylation by about 30% and abolished insulin‐stimulated glucose uptake. The stimulating effect of resveratrol (RSV) on AMPK phosphorylation was observed in cells cultured in NG or HG medium, by about 50% and 65%, respectively. Glucose uptake was also increased in HG‐cultured podocytes treated with RSV.We found that impairment of insulin induction of glucose uptake into podocytes cultivated in the presence of high glucose concentrations for long periods of time is associated with decreased AMPK phosphorylation in an SIRT1‐dependent manner. This work was supported by grant from the National Science Centre (Grant 2012/05/N/NZ5/01448).
Effects of Norepinephrine on Blood Pressure and Intra‐renal Perfusion and Oxygenation in Ovine Hypotensive Sepsis
Authors: May Clive , Kosaka Junko , Evans Roger , Bellomo Rinaldo , Lankadeva Yugeesh 
Published: June 2021

Background and AimsIn sepsis, norepinephrine (NE) is a primary treatment to maintain arterial pressure, but its effects on intrarenal oxygenation and perfusion are unclear. We therefore examined the effects of NE on mean arterial pressure (MAP), renal blood flow (RBF), urine flow (UF) and renal cortical and medullary perfusion and oxygenation during hypotensive sepsis in conscious sheep.MethodsSheep were instrumented with a renal artery flow probe, and fiber‐optic probes in the renal cortex and medulla to measure tissue PO2 and perfusion. Sepsis was induced by infusion of E coli for 32 h. NE (0.4 μg/kg/h) was infused intravenously from 25‐30 h of sepsis (n=5).ResultsSepsis was characterized by hypotension (‐10 mmHg), increased RBF and oliguria. At 24 h of sepsis, cortical tissue perfusion (1163±37 to 1607±200 mmHg) and PO2 (30.8±3.9 to 37.4±5.3 mmHg) had increased, but medullary perfusion (1423±113 to 621±100 BPU) and oxygenation (31.3±1.7 to 16.1±3.8 mmHg) were reduced. Infusion of NE restored MAP and UF, did not change cortical perfusion and oxygenation, but further reduced medullary perfusion (to 540±200 BPU) and oxygenation (to 12.3±3.1 mmHg).ConclusionsHypotensive sepsis was associated with reduced medullary perfusion and oxygenation, which may play a pivotal role in development of AKI. Administration of NE reversed sepsis‐induced hypotension and oliguria, but caused a further decline in medullary perfusion and oxygenation. Although NA treatment restored blood pressure in sepsis, it exacerbated medullary hypoxia, which may worsen kidney injury in the long term.
Physiological changes in plasma [K+] affect NCC function via Cl‐ inhibition of WNK4
Authors: Terker Andrew , Yang Chao‐Ling , Ellison David 
Published: June 2021

We have shown that dietary K+ modulates NCC via plasma K+ ([K+]p). [K+]p determines distal convoluted tubule (DCT) membrane potential and therefore, intracellular chloride ([Cl‐]i) (estimated to be near 20 mM). Extracellular [K+] modulates NCC in HEK cells via endogenous WNK1, but HEK [Cl‐]i is higher than DCT [Cl‐]i. WNK4 DCT abundance and redistribution in response to K+ intake suggests that it plays a dominant role in vivo, but this model requires that Cl‐ affects WNK4 at low, physiological [Cl‐]i.To test this, we compared WNK1 and WNK4 kinase activities on SPAK. Although Cl‐ inhibited both WNK1 and WNK4, the half maximal inhibiting [Cl‐] was much lower for WNK4 than WNK1.To confirm that WNK4 Cl‐ sensitivity affects SPAK and NCC activity in cells, we mutated the WNK4 Cl‐‐sensing domain (WNK4 LL‐FF) that is homologous to the WNK1 domain. Although WT WNK4 reduced pSPAK in HEK cells, WNK4 LL‐FF increased it. Kinase‐dead WNK4 LL‐FF returned pSPAK to WT WNK4 levels. Furthermore, WNK4 LL‐FF increased pNCC compared to WT WNK4.To confirm the physiological dominance of this pathway, we tested effects of multiple mouse models, including dietary manipulations (both Na+ and K+), drug treatments (amiloride), and genetic manipulations (MR knockout). A tight relationship between [K+]p and pNCC was observed (pNCC=42.95[K+]‐3.1, R2=0.77), which was linear in the physiological range of [K+]p. Between 5 mM and 3.5 mM, for every 0.1 mM decrease in [K+]p, pNCC increased by 20%.Lastly, dietary K+ titration (0% to 5%) produced a linear increase in [K+]p from 2.9 mM to 3.85 mM. [K+]p and pNCC were also highly correlated (pNCC=‐0.63[K+]+3.2, R2=0.63).WNK4 kinase activity is Cl‐‐sensitive in the range of DCT [Cl‐]i, while WNK1 inhibition requires higher [Cl‐]. pNCC tightly correlates with [K+]p throughout the physiological range in multiple models.
Long‐term Telemetric Blood Pressure Measurement in a Translational Model of Non‐human Primate Spontaneous Hypertension
Authors: Osborn J , Rhoads M , Collett J , Beierschmitt A , Dascanio J , Knot H 
Published: June 2021

A non‐human primate model of spontaneous hypertension has potential for understanding mechanisms of cardiovascular disease but requires a novel method for telemetric blood pressure measurement. Stellar Telemetry solid‐state pressure sensors were surgically implanted into the abdominal aorta of feral, male monkeys (Chlorocebus aethiops sabaeus). Systolic (SBP), diastolic (DBP) and mean (MBP) arterial pressures, core body temperature and heart rate were determined using different data acquisition parameters to assess system precision and reliability in this physically active non‐human primate. Animals were pre‐phenotyped for normotension (NT) or hypertension (HT) using forearm plethysmography. Various recording parameters yielded consistent blood pressure in NT (MBP=104±4.35 mmHg) and HT (MBP=126±7.57 mmHg) animals. Ultrasonography documented effective placement of sensors within the aorta lumen. Consistent aortic blood pressure recordings were obtained for 6 months post catheter implantation. Necropsy revealed no sensor induced blood or organ pathologies. The Stellar Telemetry system effectively monitors conscious blood pressure, heart rate and body temperature in active primates allowing for physiological assessments during natural social interactions and species specific behaviors. This model of hypertension in an old world, non‐human primate is translational to human essential hypertension and allows for new directions in a genetically similar species.Supported by Biomedical Sciences Research Group, LLC; TSE Systems, Inc.; Behavioural Sciences Foundation
Induced Pan‐nephron Mineralocorticoid Receptor Knockout Causes Na+ Wasting and K+ Retention
Authors: Terker Andrew , Lazelle Rebecca , yang Chao‐Ling , Ellison David 
Published: June 2021

The mineralocorticoid receptor (MR) plays a key role in Na+ and K+ homeostasis. Constitutive MR deletion is lethal, but deletion along the connecting tubule (CNT) and collecting duct (CD) has relatively mild effects. To determine if this difference reflects MR actions along other nephron segments, we deleted MR along the entire nephron.Using the doxycyline‐inducible Pax8‐rtTA system, we deleted MR in the nephron of adult mice; RT‐PCR confirmed substantial mRNA reduction. MR knockout (MR KO) mice survived, but displayed weight loss, mild hyperkalemia, Na+ wasting, and elevated plasma aldosterone at baseline. Although the abundance of ENaC was not affected, total and phosphorylated NCC (pNCC) abundance were slightly reduced.Low Na+ diet (0.02% Na+) enhanced the Na+‐wasting phenotype with dramatic weight loss, hyponatremia, and severe hyperkalemia (6.57 mM). Although Na+ deprivation increased pNCC in WT, it strikingly reduced pNCC in MR KO. In contrast, Na+ deprivation did not affect β ENaC in WT, but increased it in MR KO.High K+ diet (5% K+) also produced weight loss, hyponatremia, and hyperkalemia (7.58 mM) with increased β ENaC abundance and decreased pNCC abundance in MR KO. It also produced significantly more volume contraction (Δ Hct) in MR KO than in WT.Induced pan‐nephron MR KO mice display a more severe phenotype than CNT/CD MR KO, but a less dramatic one than constitutive total body KO. Though unchanged at baseline, increased β ENaC abundance following diet changes likely reflects MR‐independent regulation; the phenotype suggests that MR is required for activation, not synthesis. Plasma K+ appears to drive changes in NCC. Thus, baseline reductions of NCC in MR KO appear to be secondary to hyperkalemia, rather than direct MR effects in the DCT.