bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oral vitamin C prevents the attenuation in flow mediated dilation during prolonged sitting (546.3)
Authors: Thosar Saurabh , Bielko Sylvanna , Wiggins Chad , Mather Kieren , Klaunig James , Wallace Janet 
Published: June 2021

Prolonged sitting has been hypothesized to impair endothelial function via mechanisms involving oxidative stress. This study was designed to determine if Vitamin C prevents the decline in flow mediated dilation (FMD) during 3hr of sitting.Methods: Eleven inactive, non‐obese, healthy men (24.2±4.4 yrs) participated in two randomized 3 hr sitting trials, performed fasting in the morning on both occasions. In the prolonged sitting (SIT) trial, subjects were seated for 3 hours without moving their lower extremities. In the vitamin C trial (VIT) subjects sat similar to the SIT trial, but were asked to swallow two vitamin C tablets (1000 mg and 500 mg) at 0:30 and 1:30 hr respectively. Superficial femoral artery (SFA) FMD was measured every hour for 3 hrs. Paired sample t‐tests were performed to examine the differences at each time point between SIT and VIT trial. Significance was set at p蠄0.05.Results: Baseline SFA FMD% did not differ between the study conditions (SIT 5.05±3.77; VIT 2.74±2.32). However, FMD% was significantly different between conditions at 1hr (SIT 0.56±0.88; VIT 4.54±3.96) 2hr (SIT 1.76±1.10; VIT 5.28± 3.32) and 3hr (SIT 2.35±2.19; VIT 6.45±4.03).Conclusion: Our data demonstrate that acute oral vitamin C supplementation prevents the acute decline in SFA FMD with prolonged sitting, suggesting that oxidative stress may contribute to the associated impairment in endothelial function.Grant Funding Source: Supported by American College of Sports Medicine Foundation grant
Acute testosterone infusion does not exacerbate arrhythmias in the rat model of ischemia/reperfusion (547.15)
Authors: Dow Joan , Herring Michael , Bhandari Anil , Kloner Robert 
Published: June 2021

Introduction: With increasing direct‐to‐consumer marketing, testosterone (T) prescriptions have tripled over the past decade. Clinical literature suggests that exogenous T use may increase various arrhythmias. Therefore, we examined the effect of exogenous T in an acute rat model of arrhythmias.Methods and Results: Anesthetized female Sprague Dawley rats (250g) were given T (2.5 mg/kg, n=9) or vehicle (n=10) intravenously 15 minutes before 5 minutes of coronary artery occlusion. Rats were then reperfused for 5 minutes and arrhythmias were examined. T levels were measured one minute before occlusion. T levels were different between groups (5.4 ± 1 ng/mL control; 206.9 ± 35 ng/mL T, P < 0.001). The ischemic risk zone as a percentage of the left ventricle did not differ between groups (33 ± 2% control; 29 ± 3% T, P = 0.48). The number of episodes of ventricular tachycardia did not differ between groups (11.7 ± 3.2 control; 8.8 ± 3.0 T, P = 0.3). There was a non‐significant trend toward fewer ventricular premature beats with T (37.8 ± 10.3 control; 16.9 ± 8.9 T, P = 0.06) Conclusion: Despite large differences in T levels between groups, T had little effect on the incidence of arrhythmias, suggesting that T supplementation does not increase risk of arrhythmias.
Dystrophin absence is implicated in the transition from physiological to pathological cardiac hypertrophy (547.4)
Authors: Prado Cibele , Blefari Valdecir , dos Santos Daniele , Prado Fernanda , Silva Carlos , Fazan Rubens , Salgado Helio , Rossi Marcos 
Published: June 2021

Hypertension causes cardiac hypertrophy, cardiac dysfunction, and heart failure (HF). The mechanisms implicated in the transition from physiological to pathological hypertrophy are still unknown. Growing evidence points out to the role of inappropriate mechanical coupling in the pathogenesis of HF and the cytoskeletal proteins as the most obvious candidates for intracelular remodeling. We investigated dystrophin and its potential role in the transition from physiological to pathological cardiac hypertrophy in rats submitted to chronic abdominal aorta stenosis. Wistar rats were submitted to abdominal aorta stenosis and killed at 30, 60 and 90 days post surgery (dps). The hearts were collected and Western blot and immunofluorescence were performed for dystrophin and calpain. Blood pressure was evaluated and cardiac function evaluate by echocardiography. Data were considered significant when p<0.05. At 90 dps 70% presented hypertrophied hearts (HH) and 30% hypertrophied+dilated hearts (DH), as evaluated by echocardiography. Blood pressure increased 53,42% (30d), 50,8% (60d) and 64,36% at 90dps. Dystrophin expression at 30, 60 dps and HH animals was the same as control, but decreased in DH animals. The ejection fraction was the same as control at 30 and 60dps, however it was reduced 35% at 90d in HH and 48% in DH. Loss of dystrophin could be partly responsible for the development of heart failure in rats submitted to chronic abdominal aorta stenosis. Thus, it is essential to define the mechanistic aspects of the pathophysiological processes involved in deterioration of cardiac function and design develop strategies to inhibit and/or reverse evolution of heart hypertrophy from compensated to decompensated phase. Grants from FAPESP 09/17787‐8; 10/19216‐5.Grant Funding Source: Supported by FAPESP 09/17787‐8; 10/19216‐5
Creating targeted double‐stranded breaks in vitro and in vivo using RecA‐dependent endonucleases P1 and φW39 Ref (552.1)
Authors: Olsen Tayla , Gruber Angela , Dvorak Rachel , Cox Michael 
Published: June 2021

P1 bacteriophage recombination enhancement function (Ref) protein is an HNH class and RecA‐dependent endonuclease. RecA‐bound oligonucleotides homologous to a specific region on circular dsDNA will catalyze RecA strand‐invasion, creating a displacement loop (D‐loop). Upon Ref addition, double‐stranded breaks (DSBs) are created within the D‐loop. Thus, the Ref protein, in concert with RecA, is a programmable endonuclease. The closely related φW39 Ref protein exhibits increased RecA‐dependent endonuclease activity compared to P1 Ref. P1 Ref protein missing the disordered 76 N‐terminus residues is incapable of DNA binding and exhibits decreased nuclease activity, which indicates the importance of the N‐terminal region for these functions. Characterization of N‐terminal truncations based on charge distribution for φW39 Refs ΔN21, ΔN47, ΔN59, ΔN66, and ΔN74 revealed modulated activity for DSB formation and DNA binding. In addition to these in vitro studies, cells transformed with a plasmid containing P1 Ref and introduced to an oligo homologous to a region in the rpsL gene demonstrate recombination events with the oligo. The Ref/RecA/oligo system acts as an oligo‐targeting inducer of DSBs operating both in vitro and in vivo with potential for genome editing functions and in vitro targeting.Grant Funding Source: NIH GM32335
Isoaspartyl modification of ZAP70 signaling molecule alters T cell responses (555.9)
Authors: Yang Mei‐Ling , Clarke Steven , Mamula Mark 
Published: June 2021

The immune system is designed to protect the host by distinguishing self‐proteins from invading pathogens. However, neo‐epitopes generated from self‐proteins by post‐translational modifications can trigger autoreactive immune cells to break such immune tolerance. One such modification, isoaspartyl (isoAsp), is believed to contribute the onset of autoimmune B and T cell responses and lupus pathology. Protein L‐isoaspartyl (D‐aspartyl) methyltransferase (PIMT) is the only known repair system for abnormal isoaspartyl residues. Previously, we found that the isoAsp content in lupus‐prone MRL autoimmune mice increased and accumulated with age in brain and kidney, the major target organs in systemic lupus erythematosus (SLE). Recently, we found that the content of isoAsp modification in erythrocytes is correlated with PIMT activity in humans with SLE. The aberrant lupus T cell hyperproliferation can be rescued by PIMT overexpression. Of interest, ZAP70 is an essential kinase in T cell signaling and several ZAP70 mutations have been reported for patients with T cell immunodeficiencies. We found that isoAsp modification is present within ZAP70. In addition, ZAP70 is hyperphosphorylated upon TCR engagemant in PIMT deficient mice. Taken together, these studies demonstrate that isoAsp modification of ZAP70 TCR signaling molecule alters T cell immune responses and is associated with lupus T cell defects.Grant Funding Source: These studies were supported by NIH grant AI‐48120 to MJM.
Regulation of Nrd1 in RNA processing and termination by multiple binding proteins (561.6)
Authors: Kim Kyumin , Heo Dong‐hyuk , Kim Minkyu 
Published: June 2021

The yeast Nrd1 interacts with C‐terminal domain (CTD) of RNA polymerase II (RNApII) using its CTD‐interaction domain (CID) and associates with nuclear exosome, acting as a transcription termination and RNA processing factor. Previously, we have found that it is the Nrd1 CID that couples RNApII termination and subsequent RNA processing by recruiting nuclear exosome. However, what bridges the Nrd1 CID to nuclear exosome was not known. In this study, using yeast two‐hybrid assay, we show that two nuclear exosome cofactors Mpp6 and Trf4 directly interact with the Nrd1 CID. Various analyses indicate that these factors regulate the interaction of Nrd1 not only with nuclear exosome, but also with RNApII CTD. Thus, multiple proteins recognize the Nrd1 CID, fine‐tuning Nrd1 in both RNA processing and transcription termination.Grant Funding Source: Supported by the National Research Foundation of Korea
Replication serves as a trans‐generational epigenetic switch during SV40 infection (563.2)
Authors: Milavetz Barry , Kallestad Les , Woods Emily , Christensen Kendra , Balakrishnan Lata 
Published: June 2021

We have recently shown that the repression of early transcription during a Simian Virus 40 (SV40) infection results in different histone modifications depending upon the replicative status of the chromatin (Kallestad, et al., 2013, Frontiers in Genetics). In order to test whether replication affected other aspects of transcriptional regulation, we have analyzed SV40 chromosomes for the presence of the methylated forms of H3K4 and H3K9 following dysregulation of transcription by DRB which inhibits RNA Polymerase II elongation, and sodium butyrate which increases transcription from genes committed to transcription. SV40 chromosomes from treated and control infections were isolated between 2 and 12 hours post‐infection when only transcription was occurring or 48 hours post‐infection when transcription and replication were both occurring, purified, and subjected to ChIP analyses with antibodies to mono‐, di‐, and tri‐methylated H3K4 and H3K9 followed by real‐time PCR quantitation. Consistent with our previous published results we observed that dysregulation of transcription yielded different epigenetic readouts depending upon whether replication was occurring. Treatment with DRB resulted in a large increase in the levels of H3K9me2 and me3 in the presence of replication but had little effect on the levels of these modfications in the absence of replication. Treatment with sodium butyrate had the opposite effects. There was a significant reduction in H3K9me3 during replication and transcription but not when only transcription occurred. Taken together these results indicate that replication acts as a switch to epigenetically define the chromatin structure of newly replicated chromatin which will become new virus particles.Grant Funding Source: Supported by National Institutes of Health grant AI094441 to B.M.
Identification of a putative promoter element in intron5 of the RUNX1 gene (565.2)
Authors: Gutierrez Soraya , Hinojosa Marcela 
Published: June 2021

t(8:21) is one of the most frequent chromosomal translocation found in acute myeloid leukemia (AML) and involves RUNX1 and ETO genes. To date all the break points mapped are located in intron 5 of RUNX1 gene. Interestingly, this intron exhibits DNaseI hypersensitive sites, which has been associated to cis regulatory elements. Therefore, we hypothesize that regulatory elements are harbored in intron5 of the RUNX1 gene. In order to test this hypothesis, we performed bioinformatics analysis of ChIPseq data available from the server ENCODE to identify regions of intron 5 enriched in epigenetics marks associated with regulatory elements. We show that in hematopoietic cells one region is enrich in K4H3me, K4H3me3 and K27H3ac that co‐localizes with DNaseI hypersensitive sites. These marks have been associated with promoter modules. Indeed, when we cloned this region (PPR=putative promoter region) in a reporter vector, we found that it activates expression of the reporter gene in an orientation dependent manner. Moreover, when we analyzed putative transcription factors binding sites, we found one RUNX binding motif. Indeed when we transfected the promoter with RUNX1 expression vector we found that RUNX1 modulates the PPR expression. Using ETS database, we have assembly a putative messenger for this promoter, which is differentially expressed in several cell lines. Taken together, our results shown that a novel promoter is located in intron 5 of RUNX1 gene.Grant Funding Source: Supported by Fondecyt 1130697
Human eukaryotic initiation factor 4G (eIF4G) binds to eIF3c, ‐d, and ‐e to promote mRNA recruitment to the ribosome (566.9)
Authors: Villa Nancy , Do Angelie , Hershey John , Fraser Christopher 
Published: June 2021

Recruitment of mRNA to the 40S ribosomal subunit requires the coordinated interaction of a large number of translation initiation factors. In mammals, the direct interaction between eukaryotic initiation factor 4G (eIF4G) and eIF3 is thought to act as the molecular bridge between the mRNA cap‐binding complex and the 40S subunit. A discrete ~90 amino acid domain in eIF4G is responsible for binding to eIF3, but the identity of the eIF3 subunit(s) involved is less clear. The eIF3e subunit has been shown to directly bind eIF4G, but the potential role of other eIF3 subunits in stabilizing this interaction has not been investigated. It is also not clear if the eIF4A helicase plays a role in stabilizing the interaction between eIF4G and eIF3. Here, we have used a florescence anisotropy assay to demonstrate that eIF4G binds to eIF3 independently of eIF4A binding to the middle region of eIF4G. By using a site‐specific crosslinking approach, we unexpectedly show that the eIF4G‐binding surface in eIF3 is comprised of the ‐c, ‐d and ‐e subunits. Screening multiple crosslinker positions reveals that eIF4G contains two distinct eIF3‐binding subdomains within the previously identified eIF3‐binding domain. Finally, by employing an eIF4G‐dependent translation assay, we establish that both of these subdomains are required for efficient mRNA recruitment to the ribosome and stimulate translation. Our study reveals unexpected complexity to the eIF3‐eIF4G interaction that provides new insight into the regulation of mRNA recruitment to the human ribosome. With this new model, we are currently exploring whether different mRNAs, such as those with upstream open reading frames, are more or less dependent on this interaction for translation.Grant Funding Source: Supported by grant R01GM092927 from the National Institute of General Medical Sciences
Vitamin D supplementation in patients with diabetes mellitus type 2 on different therapeutic regimens: a one‐year prospective study (575.4)
Authors: Alkharfy Khalid , Al‐Daghri Nasser , Sabico Shaun , Al‐Othman Abdulaziz , Moharram Osama , Alokail Majed , Al‐Saleh Yousef , Kumar Sudhesh , Chrousos George 
Published: June 2021

Background: The objective of this study was to determine the effect of vitamin D3 supplementation in a cohort of Saudi DMT2 population on diet, insulin and/or different oral hypoglycemic agents and compare them with a non‐DMT2 control cohort.Methods: A total of 499 randomly selected Saudi subjects divided into 8 groups [Non‐DMT2 Control; Rosiglitazone alone; Diet; Insulin alone; Insulin+Orals; Metformin alone; Oral agents combination; Sulphonylurea alone] were included in this interventional study. All DMT2 patients were given 2000IU vitamin D3 daily, while the control group received none but were advised to increase sun exposure. Anthropometrics, glucose, lipid profile and 25‐hydroxyvitamin D (25‐OHVitD) were measured at baseline, 6 and 12 months.Results: Circulating 25‐OHVitD concentrations improved in all groups. Metformin group showed the highest change in vitamin D levels both at 6 and 12 months than baseline (p< 0.001). The insulin+oral agents group showed significant improvements in triglycerides, total cholesterol, systolic blood pressure and HDL‐cholesterol in males. Significant decreases in triglycerides were observed in the rosiglitazone and insulin+oral hypoglycemic agent groups (p‐values <0.001).Conclusion: DMT2 patients on insulin+oral agents benefitted the most in improving cardiovascular risk. Metformin but did not seem to confer other added cardiometabolic benefits.
Mitochondrial dynamics in hepatitis B and C virus persistent viral infections (575.9)
Authors: Kim Seong‐Jun , Syed Gulam , Khan Mohsin , Sohail Muhammad , Siddiqui Aleem 
Published: June 2021

Human hepatitis B and C virus (HBV and HCV) infections are the leading cause of chronic liver disease. Mitochondrial liver injury is associated with HBV and HCV infections. The objective of our studies is to demonstrate viral involvement in mitochondrial dynamics. Results: We show here that both HBV and HCV triggered mitochondrial fission and mitophagy. Both viruses induced perinuclear clustering of mitochondria, stimulated the gene expression of dynamin‐related protein 1 (Drp1) and its mitochondrial receptor, mitochondrial fission factor (Mff). Both viruses promoted Drp1 phosphorylation at Ser616 and its mitochondrial translocation followed by mitochondrial fission. Both viruses also stimulated the expression of Parkin, PINK1, and LC3B and induced Parkin recruitment to the mitochondria followed by mitophagy. Upon translocation to mitochondria, E3 ubiquitin ligase Parkin was self‐ubiquitinated and facilitated the ubiquitination and degradation of its substrate Mitofusin 2, a mediator of mitochondrial fusion. Interference of virus‐induced aberrant mitochondrial fission and mitophagy by silencing Drp1 and Parkin suppressed viral assembly and secretion with a concomitant decrease in cellular glycolysis and ATP levels. More importantly, it caused significant increase in apoptotic signaling evidenced by a notable increase in release of cytochrome C from the mitochondria, caspase‐3/7 activity, cleavage of poly(ADP‐ribose) polymerase (PARP) and caspase‐3, and apoptotic cell death. Conclusions: Aberrant mitochondrial dynamics induced by HBV and HCV infections attenuates apoptosis of infected hepatocytes. These events may also contribute to the persistent viral infection.Grant Funding Source: NIH DK 077704
Inhibition of cholesterol and fatty acid synthesis by inhibiting SREBPs prevent diabetic nephropathy in db/db mice with type 2 diabetes (579.2)
Authors: Luo Yuhuan , Wang Xiaoxin , Levi Moshe 
Published: June 2021

Sterol Regulatory Element Binding Proteins (SREBPs) are master transcriptional regulators of fatty acid and cholesterol synthesis. In this study we examined the effects of SREBP inhibition on diabetic nephropathy. To this end we treated db/db mice of Betulin for 12 weeks.We found increased renal lipid accumulation in the kidneys of db/db mice mediated by increased expression of nuclear SREBP‐1 and SREBP‐2 protein. Treatment with Betulin prevented the upregulation of SREBPs in the kidney resulting in a correspondent reduction of kidney triglyceride and cholesterol accumulation. SREBP inhibition prevented the increases in urine albumin excretion (db/db: 59±13 µg/24hr; db/db‐betulin: 21±3 µg/24hr; p<0.05) and mesangial matrix expansion as shown by PAS staining of the kidneys of db/db mice (mesangial matrix index: db/db, 2.25±0.08; db/db‐betulin, 1.60±0.11; p<0.05). The treatment also prevented podocyte loss determined by staining with p57 and WT‐1. Furthermore, improvement in oxidative stress and inflammation was also observed in the treatment groups (urinary TBARS: db/db, 181±27 mmol/day vs. db/db‐betulin, 103±24 mmol/day, p<0.05; urinary MCP‐1: db/db, 146±22 mmol/day vs. db/db‐betulin, 83±15 mmol/day, p<0.05). To determine if Betulin has direct effects in kidney podocytes, we cultured human podocytes in high glucose conditions. Betulin prevented the high glucose induced increased the expression of SREBP‐1 and SREBP‐2 and lipid accumulation in human podocytes.Our study therefore indicates a renoprotective role for SREBP inhibition in diabetic nephropathy by preventing lipid accumulation and modulating oxidative stress and inflammation.Grant Funding Source: NIH, VA
Upregulation of endothelial cell notch ligand jagged 1 promotes tumorigenesis and metastasis in breast cancer (58.2)
Authors: Ararso Yonathan , Jiang Jie , Rafii Shahin 
Published: June 2021

Angiogenesis and the establishment of a vascular network by tumor‐associated endothelial cells (ECs) are well‐described in cancer. Although ECs play an essential role in tumorigenesis by constructing vasculature, other mechanisms through which ECs support tumor survival and metastasis is largely unknown. Since Notch signaling is critical for breast carcinogenesis, we investigated the potential role of ECs in mediating Notch activation. We propose that by upregulating their expression of Notch ligand Jagged 1(Jag 1), ECs induce aberrant paracrine Notch signaling in breast cancer cells, thereby providing an instructive signal for tumor growth and progression. To determine the role of EC Jag 1 expression on breast carcinogenesis, we established 3D co‐cultures of human breast cancer cells (MDA‐MB‐231) with either wild‐type or Jag 1 knockdown (KD) human umbilical vein ECs (HUVECs). We found that Jag1 loss in ECs induced decreased tumor growth, mammo‐angioshpere formation, and CD40 and CD133 expression in MDA‐231 cells. Co‐injection of Jag1 KD co‐cultures into immunocompromised mice also resulted in decreased tumor weight and volume compared to wild type co‐injections. Conditional Jag1 deletion in ECs of PyMT‐MMTV transgenic mice also led to decreased primary tumor growth and lung metastasis. These results suggest that EC Jag1 upregulation supports Notch‐dependent breast cancer cell growth and metastasisGrant Funding Source: Supported by the Howard Hughes Medical Institute