bluuebunny/crossref_metadata_2025_split huggingface dataset:
Therapeutic Inhibition of Sphingosine Kinase SphK2 lowers Blood Pressure Levels in an Experimental Model of Hypertension by Reducing CD4+ T‐cell Responses
Authors: Don-Doncow Nicholas , Vanherle Lotte , Matthes Frank , Petzka Henning , Meissner Anja 
Published: April 2020

Hypertension is a major cause of premature death in the world and the primary contributor to target organ damage. Although many therapeutic strategies to combat hypertension and its comorbidities exist, none of the current anti‐hypertension medications target the immune system, which evolved as key player in the pathogenesis of hypertension. During hypertension, the activation of the immune system links to alterations in sphingosine‐1‐phosphate (S1P) signaling and specifically, to sphingosine kinase 2 (SphK2)‐mediated immune cell chemotaxis. Our previous findings revealed a protection from the development of hypertension in SphK2 knockout mice. In this study, we explored the efficacy of pharmacological SphK2 inhibition to lowering elevated blood pressure and immune activation during angiotensin II‐induced hypertension in mice.In a murine model of hypertension where we treated mice with the SphK2 inhibitor ABC294640 or saline for two weeks, we assessed BP levels using tail cuff plethysmography, immune cell populations using flow cytometry, and circulating S1P levels using mass spectrometry. Using decision trees as a method of supervised machine learning, we set out to identify a sequential set of rules on measurement outcomes, which predict a successful reduction of BP.Pharmacological SphK2 inhibition significantly lowered BP levels, without affecting plasma S1P levels. Notwithstanding its incapacity to lower S1P plasma levels, pharmacological SphK2 inhibition drastically affected T‐cell populations in the blood as evidenced by significantly reduced overall circulating CD4+ T‐cells compared to placebo‐treated hypertensive mice. Besides dampening T‐cell responses typically associated to hypertension (i.e., TH17 and TH1 responses), pharmacological SphK2 inhibition resulted in marked increases of the IL4+TH2 subset. Interestingly, the rules learned by a decision tree identify CD4+ T‐cells as critical modulators for BP responses. Thus, therapeutic administration of CD4 blocking antibody diminished the number of circulating CD4+ T‐cells and significantly lowered elevated blood pressure levels.Our results provide profound evidence that the SphK2‐S1P signaling axis regulates systemic immune cell homeostasis and T‐cell phenotype changes important to blood pressure regulation. Taken together, our work identified first evidence for SphK2 inhibitors as successful immune‐based therapy in hypertension.Support or Funding InformationThis research was supported by the Swedish Research Council (VR 2017‐01243), the Ake Wibergs Stiftelse (M17‐0031), and the Knut & Alice Wallenberg Foundation.
Analysis of Assembly of Complex I and Characterization Of Clinically Identified Mutations In Membrane Subunits ND2, ND4, and ND5, Using an E. coli Model System
Authors: Zhang Fang , Vik Steven 
Published: April 2020

NADH: ubiquinone oxidoreductase, also known as Complex I, is the first and largest enzyme of the respiratory chain, and has a central role in cellular energy production. We use Complex I from E. coil as a model system, which contains 13 subunits named A‐N. Subunits A, H, J, K, L, M and N, constitute the membrane arm, while the rest of the subunits, B, CD, E, F, G, and I, make up the peripheral arm. The assembly pathway of the bacterial Complex I is uncertain. The assembly pathway of subsets of the membrane subunits has been analyzed by native gel electrophoresis and by co‐immunoprecipitation. A gentle detergent, dodecyl maltoside, was used to extract complexes from cellular membranes. Expression of all subunits leads to a large complex in native gels that appears to be Complex I. Expression of subsets of the membrane subunits leads to formation of sub‐complexes M‐N, J‐K‐M‐N, and A‐H‐J. Subunit L only formed complexes when all subunits were expressed. This question was further addressed by expressing the subunits from 2 different plasmids, simultaneously, or sequentially. In addition several clinically identified mutations in subunits L, M and N (ND5, ND4, and ND2, respectively) were constructed, and analysis by western blotting, native gel electrophoresis, and NADH oxidase activity is underway. In conclusion, E. coli Complex I is an effective model system for studies of assembly and analysis of human mutations.Support or Funding InformationThis work was supported by a NIH grant R15 GM 126507.
Perinatal nicotine exposure alters miR‐181a‐mediated signaling leading to gender‐dependent development of cardiac ischemia‐sensitive phenotype in adult male offspring
Authors: Jian Jie , Zhang Peng , Li Yong , Liu Bailin , Xiao Daliao 
Published: April 2020

Back groundCigarette smoking/nicotine exposure during pregnancy is one of the major perinatal insults resulting in an increased risk of cardiovascular diseases in offspring. However, the fetal nicotine exposure‐induced programming of adult cardiovascular dysfunction remains largely elusive. The present study tested the hypothesis that perinatal nicotine exposure caused gender‐dependent increase in heart vulnerability to ischemia‐reperfusion injury and cardiac dysfunction in adult male rat offspring through up‐regulation of miRNA‐181a (miR‐181a)‐mediated signaling pathway.MethodsNicotine or saline was administered to pregnant rats via subcutaneous osmotic minipumps from gestational day 4 until postnatal day 10. The adult (~ 3 month old) offspring were treated with miR‐181a antisense (LNA‐miR‐181a) (10 mg/kg × 2 every 5 day, i.p.) or saline. After 10 days of treatment, the rats underwent the cardiac ischemia/reperfusion (I/R) procedure and echocardiography analysis, and the left ventricle (LV) tissues were isolated for molecular biological studies.ResultsPerinatal nicotine exposure enhanced I/R‐induced cardiac infraction and dysfunction in adult male but not in female offspring. The miR‐181a levels in LV tissues were significantly higher in the nicotine‐treated group than the saline control group. In addition, nicotine exposure decreased global DNA methylation levels but enhanced AT1 and AT2 receptor protein expression, and ROS production in LV tissues in the male offspring. Furthermore, the nicotine exposure up‐regulated autophagy‐related proteins (Atg‐5, beclin‐1, LC3 II) expressions as compared to controls in the male offspring. The most importance, treatment with LNA‐miR‐181a reversed nicotine‐mediated I/R‐induced cardiac infarction and dysfunction in male offspring, which was associated with an elimination of the nicotine’s effects on miR‐181a expression, DNA methylation, AT1R/AT2R protein, ROS, and autophagy‐related proteins expressions in the male offspring.ConclusionOur data demonstrated that perinatal nicotine exposure could cause a gender‐dependent fetal programing of adult heart ischemia‐sensitive phenotype. Our findings further suggest that miR‐181a plays a casual role in nicotine‐mediated up‐regulation of oxidative stress, renin‐angiotensin system (RAS) and autophagic flux, which may contribute to the development of ischemia‐sensitive phenotype in adult male rats.Support or Funding InformationSupported in part by the NIH grants: R01HL135623, R03DA041492, and R01HD088039; TRDRP grants: 29IR0437 and T30FT0936
SLO and Steady: Role of Streptolysin O during Inflammasome Activation in Group A Streptococcus‐infected THP‐1 Macrophages
Authors: Alcantara Cheldon Ann T. , Okumura Cheryl Y.M. 
Published: April 2020

Group A Streptococcus (GAS; Streptococcus pyogenes) is a Gram‐positive bacterium that infects millions of people globally each year, with a number of cases developing into serious infections such as septicemia, necrotizing fasciitis, and streptococcal toxic shock syndrome. Upon phagocytosis of GAS, intracellular detection of the bacteria triggers a localized inflammatory response by activation of the NLRP3 inflammasome, a cytosolic multimeric protein complex that produces pro‐inflammatory cytokines. A two‐signal system is required for NLRP3 activation which 1) induces transcription of the oligomer components and pro‐IL‐1β, and 2) detects cellular damage to elicit cleavage of pro‐IL‐1β to mature IL‐1β and subsequent extracellular release. Although several GAS proteins have been reported to trigger NLRP3 inflammasome activation, the mechanisms by which bacteria cause inflammation are generally unknown. We have shown that proteins up to 40kDa can escape GAS‐infected phagosomes via Streptolysin O (SLO)‐induced pores, which suggests that either a host phagolysosomal protein or a secreted bacterial protein is detected by cytosolic pathogen recognition receptors (PRRs) to trigger NLRP3‐induced inflammation. To test this, we first infected THP‐1 macrophages with WT or heat‐killed (HK) GAS to establish if a secreted protein activates the inflammasome by monitoring IL‐1β secretion using enzyme‐linked immunosorbent assay (ELISA). We found that HK GAS did not stimulate IL‐ Iβ release, indicating that secretion of bacterial components are necessary for inflammasome activation. To determine essential proteins for GAS‐induced inflammation, we infected THP‐1 macrophages with various secretory protein knockout strains and found that only strains lacking SLO displayed significantly decreased IL‐1β release, confirming that pore formation is necessary for inflammasome activation. Using recombinant SLO (rSLO), we found that the protein itself does not stimulate IL‐1β release. However, when rSLO is coupled with HK GAS, IL‐1β release occurs, indicating that host phagolysosomal proteins may be the trigger for inflammasome activation. The information gained through our investigation provides insight into how GAS and possibly other pathogens or agents that damage the phagosome activate the inflammasome, which may contribute to the development of more effective therapies for infections that cause life‐threatening inflammation.Support or Funding InformationAmerican Heart Association (17GRNT3410851), Occidental College Undergraduate Research Center
Systems thinking in biochemistry: Assessing students’ understanding of metabolic pathway dynamics and regulation
Authors: Manley Andrew , Villafane Sachel M. , Lewis Jennifer E. , Loertscher Jennifer , Minderhout Vicky 
Published: April 2020

Systems thinking requires consideration of dynamic processes, how parts of a whole interact through causal relationships, and how such systems change over time, often in response to environmental stimuli. A systems thinking approach is essential to understanding the complexities of metabolic pathways, yet few tools exist to probe students’ proficiency in this area. We have developed and used an assessment instrument to measure undergraduate students’ understanding of biochemical pathway dynamics and regulation in a metabolic context. A community of biochemistry educators was involved in an iterative process of designing and testing the instrument and accompanying rubric. The assessment instrument was embedded on final exams in an introductory biochemistry course and student responses were collected over several terms. Analysis of student responses showed that most students were able to interpret visual conventions in an unfamiliar metabolic pathway. Furthermore, many students could make basic predictions about how the system would be expected to respond to changes. However, fewer students generated nuanced responses that accounted for both microscopic changes at the protein level and macroscopic changes in pathway product outputs. Interviews revealed that students struggled to process the volume of complex information provided in prompts and the metabolic pathway diagram. This suggests that supporting information processing skills may be an important part of teaching systems thinking and metabolic logic.Support or Funding InformationNSF‐DUE‐1224868
Relaxin‐3 receptor (RXFP3) mediated modulation of central respiratory activity
Authors: Furuya Werner Issao , Dhingra Rishi R. , Gundlach Andrew L. , Hossain Mohammed Akhter , Dutschmann Mathias 
Published: April 2020

The neuropeptide, relaxin‐3, is expressed by pontine nucleus incertus (NI) neurons. Relaxin‐3 and synthetic agonist peptides modulate arousal and cognitive processes via activation of the
rela
xin‐
family
peptide 3 receptor (RXFP3). We recently demonstrated that a double‐chain RXFP3 peptidomimetic (RXFP3‐A2) in the nucleus of the solitary tract (NTS) triggered a mild stimulation of respiration and augmented the chemoreceptor reflex in an in situ perfused brainstem preparation (
Furuya et al., 2020). In the present study, we assessed the central respiratory effects of systemic application and local microinjection into the NTS, Kölliker‐Fuse nucleus (KF) or NI of a single chain RXFP3 peptidomimetic (B18) in the perfused brainstem preparation.Systemic application of B18 (2 μM) triggered a dose‐dependent increase in respiratory rate by 22 ± 8%. At this concentration of B18, the NaCN‐evoked (0.1% w/v, 100 μl, bolus injection) tachycardia of the arterial chemoreceptor reflex was augmented by 95 ± 14% compared to control (p<0.001, n=4). Local microinjections into the NTS also increased respiratory frequency (28 ± 5%, p<0.05, n=6) and enhanced the NaCN‐evoked tachycardia by 59%. Microinjections into the KF only triggered a mild increase in respiratory frequency (18 ± 7%, p<0.05, n=6) but had no effect on the NaCN‐evoked chemoreceptor reflex. Finally, microinjections into the NI (n=6) had no effect on either stationary breathing activity, or on the chemoreceptor reflex. We conclude that relaxin‐3 neurons target RXFP3 in respiratory control areas and acts as a general respiratory stimulant, causing mild increases in respiratory frequency. Importantly, RXFP3 stimulation significantly enhanced the respiratory response of arterial chemoreceptor reflex, implicating a major neuromodulatory role in this specific reflex pathway.
Long Term Effects of Low Dose Radiation Exposure During Late Gestation on Cardiac Metabolism and Oxidative Stress
Authors: Nemec-Bakk Ashley , Niccoli Sarah , Davidson Caitlund , Boreham Douglas , Lees Simon , Khaper Neelam 
Published: April 2020

An adverse in utero environment can result in fetal programming that can manifest as diseases later in life. Ionizing radiation (IR) is known to cause detrimental fetal programming especially during organogenesis. High doses of radiation cause severe cellular damage that can lead to mortality, however, the physiological effects of low dose radiation are not fully understood. This study examines the effect of low to non‐lethal radiation exposure during late gestation on cardiac metabolism and oxidative stress in adult mice. Pregnant C57BL/6J mice were exposed to 50, 300, or 1000mGy of gamma radiation or were sham irradiated on gestational day 15. At 4 months of age, 18FDG uptake was observed using PET imaging as an indicator of cardiac glucose uptake. Western blot was used to determine changes in 4‐hydroxynonenal adduct formation, catalase, superoxide dismutase (SOD), and glutathione peroxidase (GPx) protein expression and catalase, SOD and GPx enzyme activity was measured. Both male and female irradiated pups had lower body weights when compared to the sham group. Female pups receiving 1000mGy in utero, demonstrated a significant increase in 18FDG uptake and increased glycogen storage compared to sham group. However, female pups receiving 50mGy IR did not show a significant difference in 18FDG uptake or glycogen storage when compared to sham. Male pups did not exhibit increased 18FDG uptake, however at 50 and 300mGy IR there was decreased glycogen storage compared to sham. The reduced/oxidized glutathione redox ratio, a marker of oxidative stress, was significantly decreased in the female 300mGy and 1000mGy groups compared to sham but there was no change in males. We conclude that non‐lethal doses of radiation during late gestation can alter glucose uptake and storage as glycogen as well as oxidative status in female off‐spring. These data provide evidence that non‐lethal doses of radiation during the third trimester alter cardiac metabolism later in life and sex may have a role in fetal programming.Support or Funding InformationThis work was funded by the Natural Sciences and Engineering Research Council of Canada (NSERC) and by our industry partner, Bruce Power.
Epigenetic Mechanisms Involved in Anti‐Inflammatory Actions of a Diabetes Regulated lncRNA DRAIR in Monocytes
Authors: Reddy Marpadga A. , Amaram Vishnu , Das Sadhan , Tanwar Vinay Singh , Ganguly Rituparna , Wang Mei , Lanting Linda , Zhang Lingxiao , Wu Xiwei , Devaraj Sridevi , Natarajan Rama 
Published: April 2020

Type 2 diabetes (T2D) is associated with monocyte activation and chronic inflammation implicated in accelerated cardiovascular disease. Evidence shows that epigenetic mechanisms and long non‐coding RNAs (lncRNA)s can regulate inflammatory phenotype of monocytes, but their role in T2D induced monocyte dysfunction is unclear. Here, we describe the regulation and functions of a novel lncRNA
Diabetes
Regulated
anti‐
inflammatory
RNA (DRAIR) in monocytes. Using RNA‐seq we identified downregulation of several anti‐inflammatory genes and lncRNAs including DRAIR in peripheral blood CD14+ monocytes isolated from subjects with T2D versus healthy controls. Further studies showed that high glucose and palmitic acid significantly downregulated DRAIR expression in CD14+ monocytes and THP1 human monocytes. Conversely, DRAIR was upregulated by anti‐inflammatory cytokines and by PMA (inducer of macrophage differentiation). ChIP assays showed that KLF4 transcription factor binds at KLF4 binding sites in the DRAIR promoter and KLF4 overexpression upregulates DRAIR expression in monocytes. Loss and gain of function approaches revealed that DRAIR regulates anti‐inflammatory phenotype in monocytes and macrophages. Mouse orthologous Drair was also similarly downregulated in macrophages from T2D db/db mice and its knockdown with LNA‐GapmeRs increased expression of pro‐inflammatory genes. Furthermore, we found that DRAIR is a chromatin associated lncRNA. Chromatin isolation by RNA purification and RNA‐immunoprecipitation revealed DRAIR interaction with chromatin near target genes and with a histone methyl transferase G9a. Mechanistically, DRAIR overexpression inhibited G9a recruitment and enrichment of the repressive histone modification H3K9me2 at anti‐inflammatory genes. Together, these results demonstrate that DRAIR can mediate anti‐inflammatory phenotype in monocytes/macrophages via epigenetic mechanisms, and its downregulation in diabetes might contribute to mechanisms promoting chronic inflammation associated with diabetes complications.Support or Funding InformationThis research work was funded by National Institutes of Health grant NIH R01 DK 065073.
Effects of 2‐APB, a Stim‐Activated TRPC‐ORAI Channels Blocker, on the Vascular Remodeling and Pulmonary Hypertension Induced by Chronic Intermittent Hypoxia
Authors: Castillo-Galán Sebastian Andrés , Arenas Germán , Krause Bernardo , Iturriaga Rodrigo 
Published: April 2020

Obstructive sleep apnea (OSA), a breathing disorder characterized by episodes of chronic intermittent hypoxia (CIH), is an independent risk for systemic hypertension. Furthermore, 20–60% of OSA patients develop moderate pulmonary hypertension (PH). Rats exposed to CIH developed pulmonary vascular remodeling and PH, but the mechanisms underlaying these responses are not well known. Stim‐activated TRPC‐ORAI channel (STOC), cationic calciumpermeable channels, are overexpressed in the lung and plays a key role in the development of pulmonary vascular remodeling and PH in animals exposed to sustained hypoxia. We previously demonstrated that STOC are overexpressed in lung of rats exposed to CIH. However, whether these channels are involved in the pulmonary vascular remodeling and PH induced by CIH have not been addressed. Thus, we studied the effects of treatment of 2‐aminoethyldiphenylborinate (2‐APB), a STOC blocker, in rats exposed to CIH. Male Sprague‐Dawley rats (~200g) were exposed for 28 days to CIH (5% O2, 12 times/h, for 8h). At 14 days of CIH, rats under anesthesia were implanted with osmotic pumps containing 2‐APB (10 mg/kg/day) or its vehicle, and then rats were exposed to CIH for 14 more days. At the end of CIH exposure, the right ventricular systolic pressure (RVSP) was measure under anesthesia with urethane/α‐cloralose (800 mg/kg, i.p). Animals were then euthanized and lungs dissected to determine vascular remodeling in arteries of 200–300 μm, and the mRNA levels of the STOC forming subunits TRPC1, TRPC4, TRPC6, ORAI 1 and ORAI 2 by qPCR. 2‐APB infusion prevented the increase of the RVSP (36.5 ± 1.1 mmHg vs. 24.7 ± 1.6 mmHg, 28d‐CIH vs. 2‐APB respectively), and the pulmonary vascular remodeling (66.3 ± 9.4 % vs 48.2 ± 3.5 %, CIH, 28d‐CIH vs. 2‐APB, respectively). In addition, 2‐APB treatment reverted the increase in the mRNA levels of TRPC1, TRPC4 and TRPC6, but induced an overexpression of ORAI 1, while ORAI 2 remained unchanged. Present results suggest that STOC plays a key role in the developing of the vascular remodeling and pulmonary hypertension induced by CIH.Support or Funding InformationSUPPORTED BY FONDECYT 1150040 and 1180341
Mice with Bile acid‐CoA: amino acid N‐acyltransferase deletion are Protected from Obesity
Authors: Alrehaili Bandar D. , Lee Mikang , Takahashi Shogo , Gonzalez Frank J. , Lee Yoon-Kwang 
Published: April 2020

BackgroundBile acid‐CoA: amino acid N‐acyltransferase (BAAT) is the enzyme which is responsible for bile acid (BA) conjugation with glycine and taurine in the final step of bile acid synthesis in humans. More than 98% of BA conjugation occurs in the liver. BAAT deficiency affects lipid homeostasis in the whole body. BA conjugation is essential to improve fat solubility and counteract passive diffusion in intestine by reducing their pKa values. Thus, the absence of conjugated BAs in the duodenum will affect the absorption of dietary fat and lipid soluble vitamins.AimWe aimed to investigate the physiological effects of BAAT deficiency on the mice in diet‐induced obesity using BAAT knockout (BAAT KO) mice.MethodsMale BAAT KO mice and their littermate WT control mice were fed a WD for 15 weeks. LC‐MS were used to analyze BAs in the gallbladder. Body weight, EchoMRI analysis, CLAMS, gene expression, and plasma analysis were used to discern the severity of fat malabsorption that is associated with the deficiency of BAAT when mice were challenged with a WD.ResultsTotal BA levels in serum, liver, and urine were induced in KO mice. Levels of unconjugated BAs were significantly higher and taurine conjugated but not glycine conjugated BAs were almost completely absent in the gallbladders of KO mice. Cyp7a1, Bsep, Abca1a, Abcc4, Papss2, and Sult2a1, genes involved in BA metabolism, were strongly upregulated in the livers of KO mice. Triglyceride levels in the liver exhibited a significant reduction while fecal total lipids levels were increased in KO mice compared with controls after WD challenge. CLAMS data displays an increased in the respiratory exchange ratio and food intake in KO mice when they were on WD. Their BW gains were also significantly impaired during gestation period.ConclusionBAAT KO mice fail to gain body weight either during gestation or when they consumed a WD due to the defect in fat absorption, which is caused by conjugated bile acid deficiency. BAATKO mice is a novel model to study bile acid and lipid metabolism.Support or Funding InformationThis work was supported by a bridge fund (Y.K.L) from NEOMED.