bluuebunny/crossref_metadata_2025_split huggingface dataset:
A novel mechanism of ERK1/2 regulation in smooth muscle involving acetylation of the ERK1/2 scaffold IQGAP1
Authors: Vetterkind Susanne , Lin Qian Qian , Morgan Kathleen 
Published: June 2021

ObjectivesCeramide, a second messenger associated with cardiovascular disease, is known to activate extracellular signal regulated kinases 1 and 2 (ERK1/2). Here, we determined that the effect of ceramide on ERK1/2 is mediated by a scaffold protein.MethodsExperiments were performed with A7r5 smooth muscle cells using western blot analysis.ResultsWe show that the ERK1/2 scaffold IQGAP1 is cleaved in response to ERK1/2 activation. IQGAP1 cleavage is prevented in the presence of C6 ceramide. Conversely, treatment with a ceramide inhibitor leads to increased IQGAP1 cleavage and decreased ERK1/2 activation. Analysis of the IQGAP1 amino acid sequence revealed several potential cleavage sites for proteases of the proprotein convertase family, located to produce the observed cleavage products. Moreover, these potential cleavage sites overlap with motifs for lysine acetylation. Interestingly, deacetylase inhibitor treatment increases IQGAP1 acetylation, as detected by an acetylated lysine specific antibody, and at the same time, reduces IQGAP1 cleavage.ConclusionsBased on our data, we suggest a model in which IQGAP1 is cleaved upon ERK1/2 activation, and cleavage is regulated by acetylation of the cleavage sites. Activation of ERK1/2 by ceramide, which is known to activate acetyltransferases, appears to be mediated by acetylation‐dependent stabilization of IQGAP1. This novel mechanism could open new possibilities for therapeutic intervention in cardiovascular diseases. Funding: Dudley Allen Sargent Grant, PO1 HL086655.
Effects of ageing on sympathetically‐mediated cerebrovascular tone and autoregulation
Authors: Thompson Emma , Coney Andrew , Marshall Janice 
Published: June 2021

The role of sympathetic fibres in cerebral circulation is unclear. Evidence suggests sympathetic activity exerts a tonic constrictor influence on cerebral blood flow (CBF) and protects against increases in arterial blood pressure (ABP) at the upper limit (UL) of autoregulation. Ageing impairs sympathetic functioning, but how this affects cerebral circulation is unknown.In anaesthetised, young male Wistar rats (Y: 6‐8 weeks, n=7), we isolated and stimulated the sympathetic superior cervical ganglion (SNS) at 1‐50Hz for 5s. CBF recorded from common carotid artery after external carotid ligation, was 2.5±0.2ml/min and fell in a frequency‐dependent way to 1.1±0.2ml/min; a decrease of 58±7%. In 4 Y rats, phentolamine (10mg/kg i.v.) decreased basal ABP to near the lower limit, and CBF from 2.3±0.2 to 1.4±0.1ml/min and attenuated the response to SNS by 72±3%. In n=9 Y rats, sympathectomy increased basal CBF by 0.6±0.1ml/min. Phenylephrine was infused (0.1–200µg/kg/min i.v.) to raise ABP, and the autoregulatory UL determined by dual‐line linear regression analysis of CBF vs ABP. The UL was higher than intact Y rats (178±3* vs 168±2mmHg; P<0.05).In old rats (O: 52‐58 weeks, n=6), basal CBF was higher than Y rats; 3.3±0.2ml/min*, but was similarly decreased by SNS (to 1.6±0.2ml/min; P=0.06 vs Y: a 51±6% decrease). Phentolamine decreased basal CBF from 3.1±0.2, to a lower level than in Y rats (1.4±0.2ml/min*), but the response to SNS was similar (77±7% decrease).We propose that sympathetic fibres have similar capacity to induce vasoconstriction in O as Y rats and a similar proportion is mediated by α‐adrenoceptors. Further, sympathetic vasoconstriction limits the autoregulatory UL, at least in Y rats.British Heart Foundation funding is gratefully acknowledged.
Sex Differences in the Progression of Diabetes‐associated Cardiac Pathology
Authors: Lum‐Naihe Kelly , Raja Ahmad , Bajwa Jamal , Mahmood Abuzar , Luck Christian , Emter Craig , Pulakat Lakshmi 
Published: June 2021

Type 2 Diabetes Mellitus (T2DM) is a major contributor to cardiovascular disease (CVD). We hypothesized that there are significant sex‐related differences in the progression of T2DM‐induced cardiac pathology in pre‐menopausal diabetic female rats and age‐matched diabetic male rats. These differences were assessed in 3 study groups: ZDF male rats (ZDF‐M) and lean female rats (L‐F) on Purina 5008 diet, and ZDF female (ZDF‐F) rats on Research Diets D12468 (to induce T2DM) from the age of 6‐20 weeks. ZDF‐M went from having a ~26 fold higher fasting plasma insulin (INS) than L‐F at 9‐weeks, to <2 fold at 20‐weeks (p<0.05). In contrast, in ZDF‐F, INS was ~ 64 fold higher than L‐F at 15‐weeks and was still ~50 fold higher than L‐F and ~21 fold higher than ZDF‐M at 20‐weeks (p<0.05). Hyperglycemia was lower in ZDF‐F than ZDF‐M at all ages, but ZDF‐F had lower plasma HDL and higher LDL levels and higher % body fat and lower % lean muscle mass (as determined by EchoMRI) compared to ZDF‐M and L‐F (p<0.05). Cardiac echocardiography showed heart rate was significantly different among all three groups with ZDF‐F being greatest and ZDF‐M lowest. However, only ZDF‐M displayed cardiac diastolic dysfunction, indicated by dilatory remodeling, increased isovolumic relaxation time, increased late diastolic filling (A) and decreased E/A and E'/A' ratios. ZDF‐M had the highest 24‐hr urine clearance of Na+, K+, glucose and protein (p<0.05).ConclusionT2DM had different effects on ZDF‐F and ZDF‐M. ZDF‐F had a quicker loss of lean muscle mass and HDL despite longer hyperinsulinemic stage of T2DM, whereas ZDF‐M had higher HDL, but worse cardiac dysfunction.Funding: LSME, UM‐Columbia (LP), NIH 1R01HL118376‐01(LP), R01HL112998 (CAE).
Brain Oxidative Stress in Neural Mechanism of Programmed Hypertension to Maternal High Fructose Diet
Authors: Wu Kay , Tain You‐Lin , Chan Julie 
Published: June 2021

Early life exposure to adverse environments can lead to a variety of adult diseases by a process referred to as developmental programming. Maternal high fructose diet (HFD) promotes programmed hypertension in adult offspring, although the underlying mechanism is not fully understood. Brain oxidative stress is pivotal in neural mechanism of hypertension. We tested in this study the hypothesis that brain oxidative stress contributes to programmed hypertension in adult offspring to maternal HFD. In normotensive rats, maternal HFD during gestation and lactation led to insulin resistance, increase in sympathetic activity and hypertension in the 3‐month‐old young offspring. This was associated with augmented neurogenic sympathetic vasomotor tone and high tissue levels of reactive oxygen species (ROS) at the brain stem. Maternal melatonin treatment or simvastatin treatment to the 2‐month‐old offspring significantly ameliorated oxidative stress in the brain stem of the offspring. Simvastatin treatment also abrogated sympathetic overexcitation and prevented the development of programmed hypertension in the 3‐month‐old rats to maternal HFD. These results suggest that brain stem oxidative stress may contribute to sympathoexcitation and programmed hypertension in the offspring to maternal HFD.This study was supported by grant (CMRPG8C0051) from Kaohsiung Chang Gung Memorial Hospital.
Afternoon Spot Urine Osmolality as a Biomarker of Hydration in Free‐living Healthy Adults
Authors: LEMETAIS Guillaume , BOTTIN Jeanne , POUPIN Marie , JIMENEZ Liliana , PERRIER Erica 
Published: June 2021

ObjectivePrevious research has highlighted links between fluid intake (FI), hydration parameters, and disease risk. Specifically, hydration markers in 24h urine samples respond quickly to a change in FI and have been linked to risk of CKD and lithiasis. However, 24h urine collection is burdensome, inconvenient, and time consuming. Spot urine collections would simplify daily hydration monitoring for researchers, clinicians, and individuals. Therefore, we assessed the equivalence of 24h and spot urine osmolality (24h Uosm; Spot Uosm) to determine whether a single spot may replace 24h collection.Methods82 healthy adults with low to high habitual FI (50%M; age 23.6±2.9 y; BMI 22.2±1.5 kg/m2) recorded all fluid consumed and collected individual voids over 24h. Uosm was measured on each void and on the pooled 24h sample. Equivalence between Spot and 24h Uosm was evaluated using the Two One‐Sided Test method (α=0.025).ResultsSpot Uosm from afternoon samples (14:00‐16:00; 16:00‐18:00; 18:00‐20:00) was equivalent to 24h Uosm whereas morning (08:00‐10:00; 10:00‐12:00) and midday (12:00‐14:00) spots tended to overestimate 24h Uosm. The mean [95% CI] difference between 24h and Spot Uosm was 287 [209;365] between 08:00‐10:00; 83 [12;154] between 10:00‐12:00; and 107 [58;157] between 12:00‐14:00. From 14:00‐16:00; 16:00‐18:00; and 18:00‐20:00, the mean difference was ‐25 [‐72;22]; 29 [‐35;92] and 12 [‐41;66].ConclusionAfternoon Spot Uosm is equivalent to 24h Uosm. Thus, short, well‐timed urine collections may represent a convenient alternative to 24h samples, providing an easy way to monitor daily hydration in real‐life conditions. Afternoon Spot could also serve as an early warning signal to increase FI for maintaining 24h euhydration.
Characterization of Atp6ap2 ((Pro)‐Renin Receptor) in Receptor Mediated Endocytosis by the Renal Proximal Tubule
Authors: Figueiredo Marta , Sihn Gabin , Müller Dominik , Nguyen Genevieve , Bader Michael , Wagner Carsten 
Published: June 2021

Atp6ap2 may be an accessory subunit of the V‐type H+ ATPase regulating organellar, cellular, and systemic acid‐base homeostasis. Here we examine whether the knock‐down of Atp6ap2 affects renal V‐ATPase function in the proximal tubule. There, V‐ATPases are important for receptor‐mediated endocytosis of low molecular weight proteins from urine via the megalin/cubilin receptors. In order to elucidate the role of Atp6ap2 in this function we used an inducible shRNA Atp6ap2 rat model and a doxycyline‐inducible kidney specific Atp6ap2 KO mouse model. Knock‐down of Atp6ap2 reduced Atp6ap2 expression by approximately 90 %. Atp6ap2 knock‐down animals showed higher proteinuria (albumin and Vitamin D binding protein).To further examine proximal tubular endocytosis, we injected animals with markers for fluid phase endocytosis (FITC‐ dextran, 10 kDa) and a for receptor mediated endocytosis (human transferrin). Immunofluorescence of kidney slices from both animal groups did not show a difference in FITC‐dextran intensity or localization. Furthermore, evaluation of receptor mediated endocytosis of human transferrin, showed in immunofluorescence stainings no differences between the animal groups but the knock‐down animals excreted human transferrin in the urine while control animal did not so. Hence, our data suggests a possible role for ATP6ap2 for proximal tubule function in the kidney; however, the defect in receptor‐mediated endocytosis is mild in rats and mice.Funded by the Swiss National Science Foundation.
Short‐term Regulation of Amino Acid Transporters by Amino Acids
Authors: Jando Julia , Jordi Josua , Verrey François 
Published: June 2021

To ensure body homeostasis amino acids (AA) are (re)absorbed by epithelial cells of the intestinal mucosa and renal proximal tubules. This sequential transepithelial transport includes an apical uptake followed by a basolateral efflux. The luminal uptake is mediated by different AA transporters but most neutral AAs are transported by the luminal Broad neutral Amino acid Transporter B0AT1 (SLC6A19).The regulation of this transporter is poorly known; in particular its potential short‐term regulation by its substrates has not been investigated. We hypothesized that similarly to glucose transporters the expression of B0AT1 might be repressed if costs of its synthesis and expression exceed its benefits and thus it would be upregulated by AAs to absorb them efficiently when available. To investigate the possible short‐term regulation of B0AT1 by AAs in vivo, we assessed in rats whether after a fast of 4 or 16 hours, intragastric AA application upregulates B0AT1 expression in intestinal brush border membranes. The time point of analysis after amino acid gavage was determined based on micro Computer Tomography measurements showing when the AA mix reached the small intestine. However, functional analysis of AA absorption in isolated ex vivo intestinal rings showed no significant difference between rats having received a water or an AA gavage. In addition, protein expression levels of B0AT1 in the intestinal brush border analyzed by Western blotting did not reveal a difference between rats having received a water or AA gavage. In conclusion, in the selected experimental conditions, the expression and function of the apical AA transporter B0AT1 was not regulated in the short‐term by the preceding application of its substrate AAs.Supported by the Swiss National Science Foundation.
Cooperation of Basolateral Epithelial Amino Acid Transporters TAT1 and LAT2 Investigated in a Double Knockout Mouse Model
Authors: Boiadjieva Emilia , Vilches Clara , Bodoy Susanna , Oparija Lalita , Jando Julia , Nunes Virginia , Verrey François , Palacin Manuel 
Published: June 2021

Basolateral efflux is a crucial step for amino acid (AA) (re)absorption across small intestine and kidney proximal tubule epithelia mediated by various transporters. There are uniporters that mediate the facilitated diffusion of essential AAs, as does for instance aromatic AA transporter TAT1 (Slc16a10) and also antiporters such as LAT2‐4F2hc (SLC7A8‐SLC3A2) that exchanges neutral AAs. To test the hypothesis that the recycling of aromatic AAs via TAT1 allows the vectorial efflux of other AAs via obligatory exchanger LAT2‐4F2hc, LAT2‐/‐ TAT1‐/‐ double knockout (dKO) mice were generated. These mice have a reduced body weight (~‐17% at 3 months) but no other overt phenotypic alteration. Under normal protein diet, they excrete in the urine, compared to LAT2‐/‐ and TAT1‐/‐ knockout mice, higher amounts of aromatic AAs and of some other AAs that are not substrates of TAT1. The amino aciduria was further increased under high protein diet and involved all proteogenic AAs but some charged ones. Screening the mRNA levels of ~20 AA transporters in the kidney suggested a trend of compensatory changes as the level of the transcript of 5 basolateral AA transporters was increased in dKO mice under high protein diet. Preliminary transport experiments with small intestine gut sacs confirm the alteration of transepithelial transport. These observations support the hypothesis that the basolateral efflux of LAT2 substrates depends on the recycling of aromatic AAs via TAT1.Supported by Swiss National Science Foundation.
Silver Nanoparticles Increase Epithelial Sodium Channel (ENaC) Currents in Isolated Sheep Pleura
Authors: Arsenopoulou Zoi , Molyvdas Paschalis , Gourgoulianis Konstantinos , Zarogiannis Sotirios , Hatzoglou Chrissi 
Published: June 2021

ObjectiveExposure to engineered nanoparticles (NPs) has been associated with lung and pleura pathology such as inflammation, fibrosis and cancer. Silver (Ag) NPs are used in a large number of consumer products and medical devices increasing therefore the possibility of user exposure. The aim of this study was to investigate the possible effects of engineered AgNPs on the function and expression of ENaC on parietal sheep pleura.Materials and methodsIn the present study the short circuit current (ISC) and the transmesothelial resistance (RTM) of sheep parietal pleura was monitored in Ussing chambers after the preincubation of the tissue with spherical AgNPs of 20nm and 60nm in size for 30 min. The effect of the AgNPs on the function of the epithelial sodium channel (ENaC) was investigated by the addition of the inhibitor amiloride (10‐5M) apically. Moreover, the expression of αENaC subunit was analyzed in these samples by Western Blotting in order to assess effects on the protein level.ResultsAgNPs (20 nm; 2μg/ml) increased the amiloride sensitive ISC indicating that ENaC function is enhanced by this treatment. The RTM of the sheep parietal pleura was not altered, suggestive of no effects on the tight junctions and the tissue integrity. Finally, the levels of αENaC expression were similar in all groups. AgNPs of 60nm had no significant effects in any of the parameters.ConclusionsAgNPs of 20 nm affect sodium permeability of the sheep parietal pleura by increasing ENaC activity. This effect is not due to increased αENaC expression. These data suggest that AgNPs induce changes in the function of pleural ENaC.
Identification of the Vertebrate RIM2 Ortholog by Genetic Complementation for Heme
Authors: M. Cabañero Javier , Nguyen An , Huston Nicholas , Knight Simon , Dancis Andrew , Paw Barry 
Published: June 2021

Heme is the critical cofactor in hemoglobin responsible for its oxygen‐carrying properties. Mfrn1 (SLC25A37), functions as the major iron importer into the mitochondria for heme synthesis. The function of Mfrn1 is highly conserved from vertebrates to yeasts given the universal requirement for heme in many biological processes. The over‐expression of a related mitochondrial solute carrier, RIM2, allowed yeast deficient for the Mfrn1 orthologs, MRS3/4, to grow on low‐iron media, thereby implicating a role for other iron transporters in heme synthesis.HypothesisTwo potential RIM2 vertebrate orthologs, SLC25A33 and SLC25A36, play a role in mitochondrial iron import to complement the hemoglobinization‐defect of Mfrn1‐deficiency in a zebrafish model.Using protein homology search, two top candidates, SLC25A33 and SLC25A36, were identified as potential orthologs for yeast RIM2. Others recently showed that these 2 carriers complemented the pyrimidine‐deficiency phenotype of ΔRIM2 yeasts (Di Noia 2014 JBC); although, the iron‐auxotrophy was not investigated.Specific Aim 1The over‐expression of vertebrate RIM2 orthologs will be evaluated for ability to rescue the anemia in Mfrn1‐deficient zebrafish, frascati.We will examine whether the over‐expression of the vertebrate RIM2 orthologs could supply sufficient iron to enable mitochondrial heme synthesis in absence of Mfrn1, thereby correcting the hemoglobin‐defect. For this purpose, we will microinject cRNA with either SLC25A33 or SLC25A36 into frascati zygotes and evaluate the restoration of hemoglobinized erythrocytes.AcknowledgmentsThis work was supported by grants from the APS (JMC, AN) and the NIH (ABD, BHP).
Involvement of Multiple Cell Signaling Pathways in Cigarette Smoke induced Modulation of Ovarian Cancer Cell (OCC) Proliferation.
Authors: Sumanasekera Wasana , Ngo Dung , Tran Liem , Nguyen Tanya , Castle Marilin 
Published: June 2021

Cigarette smoking is a known risk factor for many cancers but not the ovarian cancer. Our study examined whether cigarette smoke extract (CSE) affects ovarian cancer development using A2780 ovarian cancer cell (OCC) model. The major objective is to investigate the effects of CSE on OCC proliferation and unveil the responsible cell signaling mechanism. The specific aims are 1) to detect CSE induced OCC proliferation, 2) investigate estrogen's role and 3) unveil the responsible pathway.MethodsOCCs were cultured using standard methods. CSE was created according to a published protocol. OCCs were pre‐treated with several cell signaling pathway inhibitors and estrogen prior to CSE treatment. After CSE treatments (5%, 10% and 16%), WST‐1 reagent was added to each well, incubated for 3 hours, and the production of WST‐1 formazan, which is an indicative of cell proliferation, was detected.ResultsCSE stimulated OCC proliferation and this stimulation is significant in estrogen treated cells. Estrogen receptor / β2 adrenergic receptor blockage using the antagonist, ICI 118.551, has increased OCC proliferation and this increase was attenuated by CSE exposure. Blocking ERK1/2 pathway, using the antagonist U0126 significantly reduced CS induced OCC proliferation in non‐estrogen treated cells.ConclusionCSE activated OCC proliferation. Estrogen and β2 adrenergic receptor pathways showed protection towards OCC proliferation and CSE attenuated the protective effects. Activation of ERK signaling contributes to the CSE induced OCC proliferation in non – estrogen treated cells. In estrogen treated cells CS may cause OCC proliferation via non ERK related signaling.
SIRT3 Blocks Doxorubicin Induced Cardiac Hypertrophic Response by Suppressing ROS Synthesis from Mitochondria
Authors: Pillai Vinodkumar , Samant Sadhana , Kim Gene , Gupta Mahesh 
Published: June 2021

Background and ObjectiveDoxorubicin is widely used to treat different types of cancers. Most serious adverse effect of doxorubicin is cardiomyopathy. Here we investigated whether the mitochondrial deacetylase SIRT3 can attenuate doxorubicin induced cardiac hypertrophy in mice.Methods and ResultsDoxorubicin treatment induced increased ROS levels in cardiomyocytes, which was significantly reduced by the overexpression of SIRT3. Further, SIRT3 overexpression significantly decreased doxorubicin induced cardiomyocyte death. Doxorubicin also induced exacerbated mitochondrial DNA damage in SIRT3 knockout cardiac fibroblasts (CF) as well as in mouse embryonic fibroblasts (MEFs). These results suggest that SIRT3 is capable of reducing doxorubicin induced ROS synthesis from mitochondria, thereby blocking its deleterious effects. To examine the cardioprotective effects of SIRT3 from doxorubicin induced damage in vivo, we treated wild type and cardiac‐specific SIRT3 over‐expressing transgenic mice with a cumulative dose of 15mg/kg of doxorubicin. Mice expressing cardiac‐specific SIRT3 (Sirt3‐Tg) showed 33% reduced HW/BW ratio compared to control mice. Echocardiographic evaluation of hearts showed significantly reduced fractional shortening in control mice compared to Sirt3‐Tg mice (24.6 vs 34.7 %, P<0.05)). Further, Masson's trichrome staining showed significantly reduced fibrosis in doxorubicin treated Sirt3‐Tg mice, compared to controls, thus suggesting that SIRT3 is capable of blocking doxorubicin‐induced cardiac hypertrophic response.ConclusionOur study suggests that SIRT3 is an endogenous negative regulator of doxorubicin induced cardiac hypertrophic response.
The effects of Receptor Interacting Protein 3 on necroptosis in RGC‐5 following elevated hydrostatic pressure
Authors: Shang Lei , Xiong Kun , Huang Jufang 
Published: June 2021

ObjectiveRIP3 has been found to induce necroptosis. Previous study have demonstrate necroptosis is an important neuronal death mode in retinal ischemia, and RIP3 may relate to necrosis in our observation. The lack of RIP3 inhibitor limited our study in vivo, so we first identify necroptosis in RGC‐5 following EHP, and then detect the protein level of RIP3, the percentage of necrosis using the pressure chamber via rip3 RNAi. Finally, we try to elaborate the mechanism of necroptosis.MethodsAfter 6 hr, 12 hr, 24 hr of recovery, we execute PI‐staining with different pressure values insults, then detected the level of RIP3 expression and the number of necrosis cells using western‐blotting, fluorescence‐staining. We analyzed the percentage of necrosis in 24 hr to identify the existence of necroptosis within necrostatin‐1. Finally rip3‐RNAi were carried out to get the converse evidence on necroptosis.ResultsPI‐staining in different pressure levels showed there was little necrosis cell under 60 mmHg and the percentage of cell necrosis increased following the pressure elevation. As pressure level elevated, the number of necrosis cells increased too. RIP3 expression was up‐regulated and there exist double‐labeling of some RIP3 enhance‐labeled and PI‐positives after 6 hr. The results of flow cytometry indicated the ratio of necrosis cells were decreased from 13% to 5% within necrostatin‐1, the percentage of necrosis cells decreased to nearly 7% using rip3‐RNAi.ConclusionRIP3 may participate in necroptosis following EHP.This work was supported by National Natural Science Foundation of China (81371011),Wu Jie‐Ping Medical Foundation of the Minister of Health of China (320.6750.14118), Natural Science Foundation of Hunan Province (2015JJ2187)