bluuebunny/crossref_metadata_2025_split huggingface dataset:
Activation of Hypoxia‐Inducible Factor‐1 by Sphingosine‐1‐Phosphate in vascular cells
Authors: Michaud Dumont Maude , Gratton Jean‐Philippe , Richard Darren 
Published: June 2021

Sphingosine‐1‐phosphate(S1P) is a bioactive phospholipid playing a key role in angiogenesis by promoting a variety of vascular cell events. Hypoxia‐inducible factor‐1(HIF‐1), a transcriptional activator of many genes essential for adaptation to lowered oxygen levels, is also a major angiogenic inducer. Interestingly, S1P and HIF‐1 are both implicated in different cardiovascular diseases and in tumor progression. Recent studies have shown that non‐hypoxic stimuli can activate HIF‐1 in oxygenated conditions. Here, we attempt to determine whether S1P can modulate the vascular activation of HIF‐1. We show that treatment of cultured vascular cells with S1P strongly increases HIF‐1α but not HIF‐2α protein levels, through VHL‐independent stabilization of HIF‐1α. Using pharmacological inhibitors we show that elevation of HIF‐1α expression occurs through the S1P2 receptor. We demonstrate, that the HIF‐1 nuclear dimer formed upon S1P stimulation, is transcriptionally active and specifically binds to hypoxia‐responsive elements. Moreover, in smooth muscle cells, S1P regulates genes via HIF‐1, since the transcripts are diminished when HIF‐1α is silenced. Our results therefore identify S1P as a potent inducer of HIF‐1. We believe that the discovery of novel activators of HIF‐1, such as S1P, and comprehension of subsequent downstream events will have a strong impact on different aspects of vascular biology.This work is supported by the Canadian Institutes of Health Research
Kruppel Like Factor 15 is a Critical Regulator of Angiotensin II Mediated Vascular Remodeling
Authors: Lu Yuan , Haldar Saptarsi , Hao Caili , Cui Yingjie , Doughman Yongqiu , Watanabe Michiko , Jain Mukesh K 
Published: June 2021

Kruppel Like Factor 15 (KLF15) is a transcription factor expressed in smooth muscle (VSMC) from a diverse array of vascular beds. However, the functions of KLF15 in VSMC are poorly understood. The aim of this study was to study the role of KLF15 in Angiotensin II (Ang II) mediated vascular remodeling. We employed a model in which Ang II was infused via subcutaneous osmotic minipumps at 1440ug/kg/day for 2 weeks in wild type (WT) and KLF15‐/‐ mice (age 10‐12 weeks). KLF15 expression was significantly reduced in the thoracic aorta (TA) of WT mice stimulated with Ang II. While WT mice developed aortic medial hypertrophy and perivascular fibrosis in response to Ang II, KLF15 ‐/‐ mice developed a severe degenerative aortopathy characterized by gross outward remodeling, excessive vascular inflammation, elastin lamellar disruption, reactive oxygen specious (ROS) accumulation, and apoptotic SMC loss. KLF15 ‐/‐ aorta have exaggerated expression of monocyte chemoattractant protein‐1(MCP‐1) and matrix metalloproteinase‐3 (MMP3) as well as exaggerated accumulation of p53 and its target genes (p21, bax). Promoter and ChIP studies demonstrate that KLF15 can inhibit MEF2 activity and its occupancy of the MCP‐1 promoter. Our results support a critical role for KLF15 in the regulation of Ang II mediated vascular inflammation and remodeling.Supported by NIH R01HL084154
IN VITRO CAPILLARY ENDOTHELIAL TUBES AS A MODEL SYSTEM TO STUDY CYTOTOXICITY OF DIESEL PARTICLES
Authors: Chao Ming Wei , Koslosky John , Po Iris P , Gerecke Donald R , Svoboda Kathy KH , Laumbach Robert , Gordon Marion K 
Published: June 2021

Epidemiological studies report acute exposure to diesel exhaust particles (DEP) correlates with an increase in myocardial infarctions within 48 hr. Inhaled DEP gain access to the bloodstream, but how is unknown. We have used human umbilical vein endothelial cells (HUVECs) assembled into in vitro capillary tubes to study the action of DEP. Increasing concentrations of DEP (1‐100 µg/ml) at sizes aound 2.5 um (PM2.5) increase tube cell death, as determined by LDH and TUNEL assays. DEP can be found on tubes and in the lumen of tubes in culture. Endothelial cell‐cell adherens junctional components redistribute away from the plasma membrane after a 24 hr DEP exposure, as assessed by confocal microscopy with vascular endothelial cadherin antibody. Westerns of culture medium demonstrated increased secretion of VEGF‐A with increasing doses of DEP, favoring vascular permeability. Endothelial capillary tubes produce nitrite oxide (NO) and reactive oxygen species (ROS) in response to DEP, and heme oxygenase 1 (HO‐1) and thioredoxin reductase are upregulated . Furthermore, inflammatory markers IL‐1 beta; and IL‐6 are increased in a dose dependent manner as assessed by ELISA. In summary, our in vitro capillary endothelial tube data suggest that DEP make capillaries leaky by disrupting endothelial adherens junctions and inducing secretion of VEGF‐A. The production of potentially damaging ROS is also induced by DEP.Grant Funding SourceNIEHS P30ES005022.
FREQUENCY OF CORONARY ARTERY PREDOMINANCE IN HUMAN HEARTS
Authors: Swamy Kaki Bale 
Published: June 2021

Materials & Methods30 hearts were collected from the cadavers .They were carefully dissected and examined for the type of pattern of coronary vasculature. A dye was also injected for visualization of the coronary blood vessels and observed that how many hearts are of right predominance and how many are of left predominance. Like wise 460 coronary angiograms were also studied and noted the fact that how many hearts belongs to "Right predominance and how many hearts are of "left predominance".Summary& resultsThe study with 30 cadaver hearts revealed that 90% of hearts are of right coronary predominance and 10% of them showed left predominance. From 460 angiograms of the live hearts of the patients attending the hospitals showed 85% ( 391) of right coronary artery predominance while 15% ( 69 ) of left coronary artery predominance. Among the smokers, 37% had Single vessel disease (SVD), 29% had Double vessel disease (DVD),24% had Triple vessel disease (TVD) and 10% of them had no significant cardiac disease. Among the hypertensive patients had 38% SVD, 29% DVD, 22% TVD and 11% had no significant cardiac disease. Among the diabetic patients had 38% SVD, 28% DVD, 25% TVD and 9% had no significant cardiac disease.ConclusionThe right coronary artery is the predominant artery in most cases according to this study.
Characterization of HIV‐1 subtype C I50V and I50L proteases
Authors: Bracho‐Sanchez Edith Rosvely , Fernandez Marty , Koch Sandra , Marzahn Melissa , Coman Roxana M , Dunn Ben M 
Published: June 2021

Last year alone there were approximately 2.5 million new HIV infections; contributing to the total estimate of 33.2 million people infected with HIV worldwide.HIV is classified into different groups, types, subtypes, and recombinant forms. Subtype C alone accounts for 56% of infections. The HIV protease (PR) is crucial in the replication of the virus as it cleaves precursor viral proteins into their mature forms, an essential step in viral maturation. In addition to subtypes and recombinant forms, variability of the HIV PR arises from drug resistance development, as drugs currently used in clinical treatment of HIV include protease inhibitors (PIs).Our studies have focused on introducing the mutations I50L and I50V to the HIV‐1 subtype C PR. These mutations arise upon clinical treatment with the PIs atazanavir and amprenavir, respectively. The mutant PRs have been characterized by both kinetic and crystallographic studies. The HIV‐1 C I50V PR showed an eighteen fold increase in Ki for amprenavir, and an even greater increase in Ki for lopinavir. The HIV‐1 C I50L PR on the other hand, showed a thirteen fold increase in Ki for the PI atazanavir, and a nine fold increase for lopinavir.We have also conducted crystallization studies of both mutant proteases complexed with amprenavir, atazanavir, lopinavir, and topinavir under conditions previously published by our lab. The HIV‐1 C I50V and I50L proteases both diffracted at resolutions of around 2Å.Kinetic data from our studies will hopefully impact clinical treatment of patients with the HIV‐1 C virus. In addition, structural data obtained from the crystallographic studies will have an effect on future drug design.
Hepatic CYP3A protein suppression by proteasomal inhibitors is due to induction of ER‐stress, activation of the eIF2‐alpha kinase PERK leading to translational arrest
Authors: Acharya Poulomi , Correia Maria Almira 
Published: June 2021

Hepatic cytochromes P450 3A (CYP3A) are endoplasmic reticulum (ER)‐proteins, responsible for xenobiotic metabolism. They are degraded by the ubiquitin‐dependent 26S proteasome. Consistent with this, we have shown that proteasomal inhibitors MG132 and MG262 stabilize CYP3A proteins. However, more recently MG132 was reported to suppress CYP3A due to an NF?B‐mediated regulation of protein stability. Because MG132 concentration used in those studies was 10‐fold higher than that required for CYP3A stabilization, we examined the effect of MG132 (0‐300 µM) concentration‐dependent proteasomal inhibition on CYP3A turnover in cultured primary rat hepatocytes. We found a biphasic MG132‐concentration effect on CYP3A turnover: Stabilization at 5‐10 µM with marked suppression at >100 µM. Because such CYP3A suppression could be due to MG132‐induced ER‐stress, we monitored the activity of PERK, the ER‐stress‐activated eIF2α kinase. Indeed, we found a significant (5‐fold) MG132 concentration‐dependent PERK autophosphorylation, along with a 8‐fold increase in eIF2α‐phosphorylation. Pulse‐chase and CYP3A immunoprecipitation analyses documented the dramatic translational arrest of total hepatic protein as well as CYP3A protein syntheses; thereby confirming that at high concentrations, MG132 is indeed cytotoxic and can suppress CYP3A synthesis.Supported by NIH grants GM44037, DK26506 and DK26743.
Oxygen‐Dependent Degradation of Yeast SREBP Requires the N‐End Rule E3 Ligase Ubr1
Authors: Espenshade Peter , Lee Chih‐Yung S , Hughes Bridget T , Stewart Emerson V 
Published: June 2021

Eukaryotic cells experience fluctuating environmental oxygen concentrations and elicit a physiological response to allow the organism or tissue to adapt. Sre1, the fission yeast Sterol Regulatory Element Binding Protein, is an ER membrane‐bound transcription factor that responds to changes in oxygen‐dependent sterol synthesis as an indirect measure of oxygen availability. Under low oxygen, Sre1 is proteolytically cleaved and the released N‐terminal transcription factor (Sre1N) activates gene expression essential for hypoxic growth. In addition, Sre1N turnover is regulated by oxygen. Ofd1, a prolyl 4‐hydroxylase family member, accelerates Sre1N degradation in the presence of oxygen. However, unlike the prolyl 4‐hydroxylases that regulate mammalian hypoxia inducible factor (HIF), Ofd1 uses multiple domains to regulate Sre1N degradation by oxygen; the Ofd1 N‐terminal dioxygenase domain is required for oxygen sensing and the Ofd1 C‐terminal domain accelerates Sre1N degradation. Proteasomal degradation of Sre1N requires the E2 ubiquitin conjugating enzyme Rhp6 and the N‐end rule E3 ligase Ubr1. Genetic experiments position Ofd1 in this pathway upstream of Ubr1. Thus, oxygen regulates Sre1 activity at two points to mediate adaptation to hypoxic stress: (1) proteolytic cleavage and (2) transcription factor degradation.Research was supported by the NIH‐HL‐077588 and NIH‐AI‐072186.
Novel Phosphatase SMP3 Controls Outputs of BMP Signal Transduction
Authors: Shen Tao 
Published: June 2021

Bone Morphogenetic Proteins (BMPs) and other members of the TGFb superfamily regulate cell growth and differentiation. Abrogation of BMP/TGFb signaling is associated with cancer, cardiovascular, autoimmune and skeletal diseases. The key step of BMP signal transduction is the phosphorylation of transcription factor Smad1, 5 and 8 by BMP receptors. While phosphorylated Smad1/5/8 (P‐Smad1/5/8) activates BMP‐induced gene transcription in the nucleus, protein phosphatases dephosphorylate P‐Smad1/5/8 and consequently terminate BMP signaling. The identity of the Smad phosphatase has been one of the major unanswered questions in BMP/TGFb biology.To identify Smad phosphatases, we generated cDNA encoding all the protein phosphatases in human genome and undertook a genome‐wide screen. Using combined methods of functional genomics and biochemistry, a novel cytoplasm‐localized Smad1/5/8‐specific phosphatase, SMP3 was discovered. The effects of SMP3 on controlling the level of P‐Smad1/5/8 in vivo and in vitro were analyzed by immunofluorescence and western blotting, using a phospho‐specific antibody against P‐Smad1/5/8. In vitro binding, immunoprecipitation, and bimolecular fluorescence complementation assays demonstrated that SMP3 and Smad1 directly interact in the cytoplasm. Consequently, ectopic expression of SMP3 in cells abolished BMP‐induced gene expression as measured by real‐time PCR and transcriptional reporter assays, and loss of SMP3 activity (site‐directed mutagenesis) or expression (RNA interference) greatly enhanced BMP signaling.In conclusion, SMP3 acts as a gatekeeper to prevent excessive BMP signaling through dephosphorylation and subsequent nuclear exclusion of Smad1/5/8. Our results not only gain insights into the important role of BMP signaling in human growth and development, but also are pertinent towards novel therapeutic approaches for the prevention and treatment of human diseases.
Role of JNK and p38 MAPK in Taiwanin A induced cell death
Authors: yeh sheau farn 
Published: June 2021

Taiwanin A, a lignan isolated from Taiwania cryptomerioides Hayata, has been reported to have cytotoxicity against human cancer cells. It was shown that Taiwanin A damages microtubule, induces mitotic arrest and apoptosis. Taiwanin A induced apoptosis in HepG2 cells was mediated through activating the tumor suppressor protein p53. However, whether there are other intracellular signaling pathways also involved in Taiwanin A mediated apoptosis is not known. In this study, we examined the activation of three MAPKs (mitogen activated protein kinase): ERK, p38 and JNK in HepG2 cells upon Taiwanin A treatment and the role of MAPK activation in Taiwanin A induced apoptosis.We found that Taiwanin A activated all three MAPKs. Taiwanin A induced cytotoxicity could be partially blocked by either the p38 inhibitor SB203580 or JNK inhibitor SP600125, but not by ERK inhibitor PD98059. Combined treatment of SB203580 and SP600125 showed additive effects on the inhibition of Taiwanin A's cytotoxicity suggested that both JNK and p38 may play role in Taiwanin A induced apoptosis. Inhibition of p38 activity reduced Taiwanin A‐induced p53 phosphorylation on serine 15 residue. Direct interaction of Taiwanin A activated p38 and p53 was demonstrated by immuno‐precipitation. On the other hand, inhibition of JNK activity by either SP600125 or by silencing the JNK scaffold protein JIP2 was also shown to reduce phosphorylation of Bcl‐2.Therefore, we identified two Taiwanin A induced signaling pathways; p38‐p53 and JNK‐Bcl‐2; that are involved in Taiwanin A induced apoptosis in HepG2 cells.
Acute consumption of very low carbohydrate meals lowers postprandial concentrations of insulin, leptin, and total ghrelin
Authors: Kumagai Melissa , Bergman Sarah , Smith Julie , Jordan Julia , Clemons Aaron , Gillingham Melanie , Duell Bart , Stadler Diane 
Published: June 2021

People following low carbohydrate (LC) diets report "food disinterest" that may lead to greater weight loss than other diets. Changes in weight regulation hormones that affect hunger and satiety may contribute to this heightened response. A random‐order, crossover design was used to test the hypothesis that acute consumption of LC meals reduces postprandial insulin, leptin, and ghrelin concentrations compared to high complex carbohydrate (HC) meals.Seven normal‐weight adults completed two 4‐day controlled dietary phases. Subjects consumed a standard diet for 3 days and LC (4% CHO) or HC (58% CHO) meals providing 10 kcal/kg on day 4. Insulin, leptin, and ghrelin were measured in blood samples hourly for 9.5 h after breakfast. Area under the curve (AUC) and patterns of change for each analyte were determined with differences between diets compared using paired t‐tests and Wilcoxon Signed‐Rank tests.AUC's for insulin (91±13 vs 259±30 μIU ·h/ml, p=0.0002) and leptin (4±0.7 vs 5±1.0 ng·h/ml·kg fat mass, p=0.03) were significantly lower after the LC than the HC diets. The linear term was significant for leptin, p=0.03. The linear (LC), quadratic and quartic (HC) terms were significant for ghrelin, p=0.02.Consumption of LC and HC meals resulted in different patterns of change for all analytes, and lower AUCs for insulin and leptin. These differences may explain the food disinterest and heightened weight loss associated with LC diets.
Dietary monounsaturated fatty acids, genetic polymorphism of nucleotide binding oligomerization domain 1 (NOD1) and serum HDL concentrations
Authors: Cuda Cristina , Cahill Leah , El‐Sohemy Ahmed 
Published: June 2021

Dietary fatty acids have been associated with cardiovascular disease, in part, by influencing risk factors such as serum lipids and inflammation. Nucleotide Binding Oligomerization Domain 1 (NOD1) is an intracellular protein of the innate immune system, and genetic polymorphisms of NOD1 have been associated with inflammatory conditions. The objective was to determine whether a polymorphism in the NOD1 gene (G796A) modifies the association between dietary fats and serum HDL. Men and women (n= 961) aged 20‐29 years completed a 196‐item food frequency questionnaire and provided a fasting blood sample for determining serum cholesterol concentrations and genotyping. No significant diet‐gene interactions were observed for total (p=0.16), saturated (p=0.19), monounsaturated (MUFA) (p=0.19) or polyunsaturated fat (p=0.60) on serum HDL concentrations. However, a significant association was observed between MUFA and HDL cholesterol (r=0.13, p<0.0001). The Spearman correlation between dietary MUFA and serum HDL was 0.15 (p=0.001) for those with the GG genotype, 0.18 (p=0.0003) for the GA genotype and ‐0.01 for the AA genotype (p=0.9), after adjusting for energy intake, sex, ethnicity and BMI. These results indicate that NOD1 genotypes modify the association between dietary MUFA intake and HDL cholesterol concentrations.Grant Funding SourceAdvanced Food Materials Network
Kinetics of myogenic progenitor cell (MPC) expansion and bone marrow‐derived cell recruitment in skeletal muscle regeneration
Authors: Martinez Carlo Obet , McManus Linda M , Shireman Paula K 
Published: June 2021

Muscle regeneration requires myogenic progenitor cells (MPC) and recruitment of bone marrow (BM)‐derived cells. MPC (CD34+/CD45−/Sca‐1−) and BM‐derived progenitor cells (CD45+/Sca‐1+) isolated from injured muscle undergo myogenic differentiation in vitro. However, the kinetics of MPC expansion and BM‐derived cell recruitment to injured muscle are poorly understood and were quantitated in tibialis anterior muscle using flow cytometry after cardiotoxin (CTX) injury in wild type (WT, C57Bl/6J) male mice. Maximal MPC expansion occurred 3 days post‐CTX and BM‐derived progenitor and immune cell recruitment exhibited similar kinetics; few cells present at baseline with maximal accumulation 3 days post‐CTX.MPC expansion and BM‐derived cell recruitment occurred within days of injury and demonstrated similar accumulation kinetics suggesting interactions between MPC and BM‐derived cells may be crucial to skeletal muscle regeneration. A better understanding of interactions between different cell types could result in improved strategies for muscle regeneration and tissue engineering.Supported by Veterans Administration and HL074236 and HL090196.
Novel non‐nucleoside HCV NS5B inhibitors exhibit low potential for CYP‐mediated drug‐drug interactions
Authors: Sergeeva Maria , LeBrun Laurie A , Hou Huiying , Kirkovsky Leo , Zhou Yuefen 
Published: June 2021

INTRODUCTIONHCV RNA‐dependent RNA polymerase (NS5B), essential for viral replication, is an attractive target for HCV drug discovery. We previously disclosed a novel series of potent non‐nucleoside NS5B inhibitors which bind to the "palm" site of the NS5B protein. Here we report the results of in vitro ADME studies with representative NS5B inhibitors aimed at evaluation of their drug‐drug interaction potential.METHODSTest articles were incubated in the presence of human or animal liver microsomes or Cytochrome P450 SupersomesTM (1A2, 1A6, 2C8, 2C9, 2C19, 2D6 and 3A4) and NADPH+ regeneration system and the remaining parent molecules were quantified by LC/MS/MS. CYP inhibition was assessed using Vivid® Cytochrome P450 Screening Kits (1A2, 2C9, 2C19, 2D6 and 3A4) or, for selected compounds, in human liver microsomes.RESULTSTest article stability was assessed in liver microsomes of male and female mice, rats, rabbits, dogs, monkeys and humans. The compounds showed good metabolic stability (t½ > 60 minutes) in liver microsomes of all species tested with the exception of rabbit (both genders) and male rat microsomes. 2C8, 2C9 and 3A4 were identified as CYP isoforms involved in metabolism. CYP inhibition was insignificant for all isoforms tested.CONCLUSIONSThe results suggest that CYP related drug‐drug interaction potential of the compounds evaluated in the current study is minimal.
Resveratrol reverses both thromboxane A2 receptor and non‐receptor (K+) mediated pulmonary vasoconstriction
Authors: Natale Elizabeth Kathleen , Slutzky Jessica L , Chicoine Louis G 
Published: June 2021

AbstractResveratrol (3,5,4′‐trihydroxystilbene) is an antioxidant found in red wine. Recent studies have demonstrated that resveratrol attenuates platelet activation/aggregation via increased NO/cyclic GMP formation. We tested the hypothesis that resveratrol reverses Thomboxane A2 receptor mediated pulmonary vasoconstriction. The lungs of adult male Spague‐Dawley rats (weight 225‐300 g) were isolated, ventilated (5% CO2, balance RA) and perfused with a physiological salt solution (PSS) at constant flow rate (30 mL/kg/min). U46619, a thromboxane A2 mimetic, was added to the perfusate to induce a stable pulmonary arterial pressure increase of 8‐10 mmHg (n=3). Increasing doses of resveratrol (3‐300 ug/mL) were added to the perfusate. The addition of resveratrol resulted in a dose dependent decrease in pulmonary arterial pressures. We then tested the hypothesis that resveratrol reverses non‐recptor mediated pulmonary vasoconstriction using KCl. We preconstricted the lungs with K+ (20‐30 mM), which resulted in an arterial pressure increase of 8‐10 mmHg (n=3). Increasing doses of resveratrol (3‐300 ug/mL) were added to the perfusate. The addition of resveratrol resulted in a dose dependent decrease in pulmonary arterial pressure, such that resveratrol reversed K+ constriction at concentrations >100 ug/mL. These results demonstrate that resveratrol reverses both, receptor‐mediated as well as non‐receptor mediated pulmonary vasoconstriction.