bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mitochondrial processing peptidases as a target therapy for vascular endothelial dysfunction in atherosclerosis (1146.8)
Authors: Pandey Deepesh , Bhunia Anil , Chang Fumin , Bergman Yehudis , Kuo Maggie , Serbo Janna , Berkowitz Dan , Romer Lewis 
Published: June 2021

Oxidized Low density lipoprotein (OxLDL) acts via its receptor LOX‐1 and elicits endothelial dysfunction that is considered a hallmark for initiation and progression of atherosclerosis. However, the precise mechanism by which this occurs is still unclear and is the main focus of current study. Our time course, subcellular fractionation, and immunofluorescence data support our hypothesis that Arg2 is a dual‐targeted single gene and single mRNA product found in both mitochondrial and cytosolic fractions of HAEC ‐ a novel pattern of effector system activation in mammalian vascular injury. These data indicate that OxLDL‐mediated activation of Arg2 in HAEC and in mouse aortic intima occurs via post‐translational modification and subcellular translocation of pre‐existing pools of Arg2 from mitochondria to the cytosol. Accumulated Arginase 2 in cytosol diminishes the concentration of cytosolic L‐arginine and leads to eNOS uncoupling. OxLDL‐evoked changes in cytosolic Arg2 activity are muted by Rho‐kinase inhibition, and do not occur at all in LOX‐1 null endothelial cells. In addition, inhibition or siRNA knockdown of the mitochondrial processing peptidase (MPPα) reduces the cytosolic abundance and activity of Arg2 following OxLDL stimulation. Blocking MPP with the biochemical inhibitor O‐phenanthroline also attenuates OxLDL‐mediated changes in HAEC production of ROS and NO. Finally, knockdown of MPPα by adenovirally delivered MPP shRNA interference in isolated mice aortas was associated with improved endothelium‐dependent vascular relaxation as assessed by wire myography following OxLDL exposure, when compared with aortas treated with scrambled shRNA. Hence, inhibition of Arg2 translocation to cytosol by targeting MPP could provide novel therapeutic avenues for the treatment of atherosclerosis and other cardiovascular diseases.Grant Funding Source: NIH, AHA
Fetal bovine serum influences the effect of a ligand on the activity of the SV23 splice variant of human constitutive androstane receptor (1148.1)
Authors: Lau Aik Jiang , Chang Thomas 
Published: June 2021

The naturally occurring SV23 splice variant of human constitutive androstane receptor (hCAR‐SV23) is activated by di‐(2‐ethylhexyl)phthalate (DEHP), which is detected as a contaminant in fetal bovine serum (FBS). We determined the effect of charcoal‐stripped, dextran‐treated FBS (CS‐FBS), dialyzed FBS, and regular FBS on hCAR‐SV23 activity in a cell‐based reporter gene assay. In transfected HepG2 cells cultured in Minimum Essential Medium (MEM) supplemented with 10% FBS, basal hCAR‐SV23 activity varied with the type of FBS (regular > dialyzed > CS). DEHP increased hCAR‐SV23 activity when 10% CS‐FBS, but not regular or dialyzed FBS, was used to supplement MEM. With increasing concentrations (1‐10%) of regular or CS‐FBS, hCAR‐SV23 basal activity increased, whereas the DEHP‐mediated hCAR‐SV23 activity remained constant (regular FBS) or slightly increased (CS‐FBS). Subsequent experiments identified the following optimal conditions to conduct the hCAR‐SV23 activity assay: 1% CS‐FBS in Minimum Essential Medium‐Reduced Serum (MEM‐RS) for plating of cells and for the first 24 h after plating; and then in serum‐free MEM‐RS. Under these conditions, artemisinin, artemether, and arteether increased hCAR‐SV23 activity. In contrast, they decreased it in cells cultured in MEM supplemented with 10% regular FBS. In conclusion, the type and concentration of FBS influence the effect of a ligand on hCAR‐SV23 activity.Grant Funding Source: Canadian Institutes of Health Research and Michael Smith Fdn. for Health Res.
Alterations of epigenetic signatures in hepatocyte nuclear factor 4α deficient mouse liver determined by improved ChIP‐qPCR and (h)MeDIP‐qPCR assays (1148.4)
Authors: Zhang Qinghao , Lei Xiaohong , Lu Hong 
Published: June 2021

Hepatocyte nuclear factor 4α (HNF4α) is a liver‐enriched transcription factor essential for liver development and function. In hepatocytes, HNF4α regulates a large number of genes important for nutrient/xenobiotic metabolism and cell differentiation and proliferation. Currently, little is known about the epigenetic mechanism of gene regulation by HNF4α. In this study, the global and specific alterations at the selected gene loci of representative histone modifications and DNA methylations were investigated in Hnf4a‐deficient female mouse livers using the improved MeDIP‐, hMeDIP‐ and ChIP‐qPCR assay. Hnf4a deficiency significantly increased hepatic total IPed DNA fragments for histone H3 lysine‐4 dimethylation (H3K4me2), H3K4me3, H3K9me2, H3K27me3 and H3K4 acetylation, but not for H3K9me3, 5‐methylcytosine,or 5‐hydroxymethylcytosine. At specific gene loci, the relative enrichments of histone and DNA modifications were changed to different degree in Hnf4a‐deficient mouse liver. Among the epigenetic signatures investigated, changes in H3K4me3 correlated the best with mRNA expression. Additionally, Hnf4a‐deficient livers had increased mRNA expression of histone H1.2 and H3.3 as well as epigenetic modifiers Dnmt1, Tet3, Setd7, Mllt3, Ehmt2, and Ezh2. In conclusion, the present study provides convenient improved (h)MeDIP‐ and ChIP‐qPCR assays for epigenetic study. Hnf4a deficiency in young‐adult mouse liver markedly alters histone methylation and acetylation, with fewer effects on DNA methylation and 5‐hydroxymethylation. The underlying mechanism may be the induction of epigenetic enzymes responsible for the addition/removal of the epigenetic signatures, and/or the loss of HNF4α per se as a key coordinator for epigenetic modifiers.Grant Funding Source: Supported by NIH grants ES019487, CA143656, and CA159350
Increased type VI collagen gene expression in the post‐MI human myocardium (1152.11)
Authors: Bryant Jennifer 
Published: June 2021

Cardiac fibroblasts and myofibroblasts are responsible for post‐myocardial infarction (MI) remodeling via regulation of extracellular matrix (ECM) formation. Accelerated post‐MI remodeling leads to excessive ECM deposition and fibrosis which can contribute to impaired contractile function, arrhythmias, and heart failure. Type VI collagen has been shown to induce myofibroblast differentiation in cultured cardiac fibroblasts and could contribute to accelerated post‐MI remodeling. Type VI collagen is elevated in the myocardium 7 days, 14 days, and 20 weeks post‐MI in the rat. The absence of type VI collagen improved cardiac function post‐MI in a knock out mouse model. The purpose of this study was to determine if collagen VI gene expression was elevated in human myocardium post‐MI. Autopsy samples were obtained from subjects who had died within seven days of an MI (acute MI group) and subjects who had died of a non‐heart related issue with no documented prior MI (control group). Quantitative real time PCR reactions were performed with RNaseP as a reference gene for normalization. Type VI collagen gene expression in the acute MI group was 414% greater than the control group expression, but did not reach statistical significance in this small study. However, this preliminary data indicate that type VI collagen gene expression may be significantly elevated in the post‐MI human myocardium and warrants further study.Grant Funding Source: Supported by Shenandoah University School of Pharmacy Professional Practice Plan
Extracellular ROS formation in contracting soleus muscle in mice with lung TNF‐α overexpression (1153.1)
Authors: Zuo Li , Hallman Allison , Roberts William , Wagner Peter , Hogan Michael 
Published: June 2021

Chronic obstructive pulmonary disease (COPD) commonly results in elevated levels of tumor necrosis factor‐alpha (TNF‐α). However, the mechanism of extracellular reactive oxygen species (ROS) formation in skeletal muscle isolated from pulmonary TNF‐α overexpression mice, has been overlooked. We hypothesized that ROS can be released from contracting skeletal muscle when there is increased TNF‐α formation in the lung and that this causes muscle early fatigue. Using wild type (WT) and pulmonary TNF‐α overexpression mice (Tg+), we performed a cytochrome c (cyt c) assay to measure extracellular superoxide (O2•–, one of the major types of ROS) production in isolated contracting soleus muscle. Our results showed that Tg+ soleus released higher levels of O2•– than WT during the contraction period (n = 5; P < 0.05). Tg+ soleus muscle also presented a reduced fatigue resistance compared to WT muscle. Perfusion of the contracting soleus with membrane‐impermeable superoxide dismutase, an extracellular O2•– scavenger, resulted in less cyt c reduction confirming that the type of ROS released from the Tg+ muscles was O2•–. We conclude that TNF‐α overexpression in the lung induces more O2•– release from Tg+ than WT muscle, and that the extracellular formation of O2•– markedly reduces the fatigue resistance in the Tg+ muscle. Thus, this study highlights O2•– as a potential mechanistic mediator in COPD induced muscle impairment.Grant Funding Source: Supported by NHLBI Grant PPG‐HL‐091830, NIAMS Grant AR040155, OSU‐HRS 013000
Sex influences systemic and peripheral blood mononuclear cell production of superoxide in older adults (1153.11)
Authors: Schanzle Jennifer , Deo Shekhar , Fadel Paul 
Published: June 2021

Previous work suggests that elevations in oxidative stress are associated with cardiovascular disease. Although it is well known that oxidative stress increases with age, whether this occurs differently in men and women remains unclear. Likewise, recent work indicating that mRNA expression for NADPH oxidase is greater in peripheral blood mononuclear cells (PBMCs) of older subjects did not differentiate sex effects. Therefore, we measured plasma and intracellular levels of superoxide (O2●‐), along with PBMC expression of NADPH oxidase subunits in 12 healthy older post‐menopausal women and 10 age‐matched older men. Older men demonstrated greater plasma O2●‐ levels (lucigenin chemiluminescence; men 202.73 ± 9.28 vs. women 171.67 ± 7.72, Relative Light Units; P<0.05) as well as intracellular O2●‐ in PBMCs (dihydroethidium fluorescence; men 1.94 ± 0.20 vs. women 0.96 ± 0.14, Relative Fluorescence Units; P<0.05) compared to older women. Similarly, western blot analysis demonstrated that older men exhibit greater NADPH oxidase subunit protein expression for gp91phox, p22phox, and p47phox in PBMCs (e.g., gp91phox; men 1.48 ± 0.38 vs. women 0.31 ± 0.07; P<0.05) and p67phox tended to be higher (P=0.14). These preliminary findings suggest that systemic O2●‐ levels are greater in older men compared to older women and PBMC‐derived O2●‐ production via NADPH oxidase is a likely contributing source.Grant Funding Source: Supported by NIH R01 HL093167
Interplay among superoxide, nitric oxide and hydrogen peroxide in hyperglycemia‐induced endothelial dysfunction (1153.7)
Authors: Patel Hemang , Chen Juan , Kavdia Mahendra 
Published: June 2021

Free radicals have critical involvement in both physiological and pathological processes in cardiovascular system. Their role is not clear in the regulation of hyperglycemia‐induced endothelial dysfunction. In this study, we investigated the interplay amongst the superoxide (O₂‾), nitric oxide (NO), and hydrogen peroxide (H₂O₂) levels in endothelial cells following 24 hours of hyperglycemia. Furthermore, hyperglycemic‐endothelial cells were treated with superoxide dismutase (SOD) and catalase. Hyperglycemia significantly increased O₂‾ and H₂O₂ levels and decreased NO levels in endothelial cells. Following the exposure to exogenous SOD and catalase, O₂‾ levels decreased to control levels and NO levels significantly increased in hyperglycemic endothelial cells. Regulation of O₂‾, NO and H₂O₂ following SOD and catalase exposure, indicated a tight interplay resulting in increased NO levels upon neutralization of either O₂‾ or H₂O₂. Our findings provide a direct evidence for H₂O₂ led NO level regulation through O₂‾ depletion in hyperglycemia‐induced endothelial dysfunction.Grant Funding Source: NIH R01 HL084337
Elevated levels of reactive oxygen species in heart failure patients: role for increased mononuclear NADPH oxidase expression (1153.9)
Authors: Deo Shekhar , Zimmerman Matthew , Zucker Irving , Fadel Paul 
Published: June 2021

Although heart failure (HF) patients exhibit elevated levels of ROS, the sources and mechanisms contributing to the increase in ROS remain unclear. Recent work has shown that peripheral blood mononuclear cells (PBMCs) are a major source of NADPH oxidase‐derived superoxide (O2●‐) production. Therefore, we measured systemic ROS, O2●‐, and expression of NADPH oxidase and its potential activators, angiotensin II type 1 receptors (AT1R) and Rho Kinase (ROCK) 1, in PBMCs from 6 HF (ejection fraction 22±4%) and 6 age‐matched healthy controls. Total ROS and O2●‐ levels were measured in blood using electron paramagnetic resonance spectroscopy. Protein expression of NADPH oxidase subunits (gp91phox, p22phox, p47phox and p67phox), AT1R and ROCK1 were assessed from PBMCs using western blot. Total ROS and O2●‐ levels were elevated in blood from HF patients compared to controls (P<0.05). HF patients showed augmented protein expression of all NADPH oxidase subunits (e.g. 4±1 fold increase in gp91phox; P<0.05 vs. control). ROCK1 protein expression was also greater in HF patients (3±1 fold; P<0.05 vs. control), whereas AT1R tended to be higher (2±1 fold; P=0.13 vs. control). These preliminary findings suggest that PBMC‐derived NADPH oxidase expression is up‐regulated in HF patients and may contribute to the elevated levels of ROS, including O2●‐, through a ROCK1 and/or AT1R dependent mechanism.Grant Funding Source: Supported by NIH RO1 HL 038690‐22
Increased α‐adrenoceptor sensitivity in Zucker diabetic fatty rats during anesthesia (1155.6)
Authors: Bussey Carol , de Leeuw Anne , Lamberts Regis 
Published: June 2021

Diabetics increasingly require surgical intervention for medical complications, and they experience more perioperative cardiovascular complications than their non‐diabetic counterparts. The sympathetic nervous system, acting via adrenoreceptors (ARs), is crucial for cardiovascular regulation, and is modulated by anesthesia. Therefore, we aimed to determine how diabetes alters cardiovascular AR responsiveness in vivo, and how this is affected by anesthesia.Male Zucker Diabetic Fatty (ZDF) rats and lean littermates (n=7) underwent surgery at 16 weeks. A radiotelemeter positioned in the abdominal aorta provided hemodynamic data, and a vascular access port in the femoral vein provided intravenous access. α‐ or β‐ARs were stimulated with phenylephrine (1‐100µg/kg) or dobutamine (2‐120 µg/kg) respectively, under conscious and anesthetized (2% isoflurane) conditions.Conscious diabetic rats had reduced β‐AR sensitivity (58±7 vs. 27±8 bpm; p<0.05 at 15µg/kg), which was lost during anesthesia (49±8 vs. 63±8 bpm; NS at 15µg/kg). Diabetic animals exhibited a slightly higher top α‐AR response while conscious (80±3 vs. 95±4 mmHg; p<0.05 at 100µg/kg). However, a marked increase in α‐AR sensitivity was evident in anesthetized diabetic animals (34±1 vs. 54±6 mmHg; p<0.001 at 8µg/kg). In addition, diabetes prolonged α‐AR responses, which was exacerbated during anesthesia in diabetic rats.These data indicate the importance of α‐AR mediated cardiovascular dysfunction in diabetes, particularly in the surgical setting. Inability of diabetic individuals to properly control blood pressure during anesthesia may cause undue pressures on the heart and contribute to poor cardiac outcomes.
Comparison of two techniques for measuring pulse wave velocity in children (1156.5)
Authors: Philips Nicole , Faught Brent , Hay John , Cairney John , O'Leary Deborah 
Published: June 2021

Pulse wave velocity (PWV) is used as an indicator of arterial stiffness. Carotid‐femoral PWV is the gold standard method. However, femoral pressure is difficult to measure in children and therefore carotid‐toe PWV has been used as an alternate method. Furthermore, measurement of carotid artery pressure requires highly skilled technicians, while participants are required to remain still over a time period, making this measure difficult to obtain in children. As a result, this study was undertaken to determine the effectiveness of using ECG R‐wave‐toe as an alternate method to measure PWV. Carotid‐toe PWV and R‐wave‐toe PWV were calculated for 31 healthy adolescents (16 females). Ten consecutive beats were averaged for each subject to determine the pulse transit time for each PWV method. PWV was calculated by dividing the pulse transit time by the distance travelled between the two recording sites for each method. A paired t‐test and Pearson correlation were conducted and significance was set at p<0.05. PWV estimated by the R‐wave‐toe technique was significantly lower than that estimated by the carotid‐toe technique (3.86 vs. 4.50 m/s, p<0.001). As well, a positive correlation was found between the two methods (r = 0.86, R2 = 0.75, p<0.001). Although based on a small sample, these results suggest that R‐wave‐toe measurement technique may be a simple and useful alternate method to obtain PWV in children.Grant Funding Source: Supported by Canadian Institutes of Health Research
Intermittent parathyroid hormone administration attenuates age‐related endothelial dysfunction (1156.8)
Authors: Guers John , Prisby Rhonda , Edwards David , Lennon‐Edwards Shannon 
Published: June 2021

Aging is an independent risk factor for cardiovascular disease and is characterized by a decline in conduit artery function. Parathyroid hormone (PTH) treatment has been shown to increase endothelial nitric oxide synthase (eNOS) expression. The purpose of this study was to test the hypothesis that 15 days of intermittent PTH administration would improve endothelial function in old rodents. Old (24 mo) and young (4 mo) Fischer‐344 rats were given injections of PTH (43 µg/kg/day; n=8) or phosphate buffered saline (PBS; 100 µl/day; n=9). In vitro endothelium‐dependent relaxation (EDR) and endothelium‐independent relaxation (EIR) were assessed in aortic segments to acetylcholine (ACh) and sodium nitroprusside (SNP), respectively. Aortic eNOS protein expression was assessed by western blot. EDR response to cumulative doses of ACh was significantly reduced in the old compared to young rats (p<0.05) as was maximal relaxation (Old = 72.5% ± 6.0 vs. Young = 94% ± 1.4; p<0.05). These decreases in age‐related EDR were improved significantly in the old PTH in response to cumulative doses of ACh (p<0.05) and at maximal dilation (Old = 72.5% ± 6.0 vs. Old PTH = 87% ± 1.8; p<0.05). When compared to young rats expression of eNOS was reduced (p<0.05) in old rats but not young or old PTH treated rats. These data suggest a potential role for PTH in the treatment of age‐related declines in endothelial function.Grant Funding Source: Research supported in part by NIH Grant: 1R15AR062882‐01(RDP)
Mitochondrial N‐formyl peptides cause hypotension via formyl peptide receptor activation (1157.6)
Authors: Wenceslau Camilla 
Published: June 2021

Hypotension is the major pathophysiological characteristic of systemic inflammatory response syndrome (SIRS) and sepsis. Mitochondrial N‐formyl peptides (F‐MIT) are a damage‐associated molecular pattern that activate the innate immune system via the formyl peptide receptor (FPR). We hypothesized that F‐MIT activates FPR and induces hypotension. Male Wistar rats (12‐weeks old) were cannulated (femoral artery and vein) for blood pressure recordings and drug infusion. F‐MIT infusion (0.02 or 0.2 mg/rat) decreased blood pressure (Low dose: Basal: 82±3 vs. F‐MIT infusion: 60±4*mmHg; High Dose: Basal: 79±3 vs. F‐MIT infusion: 41±3*mmHg;*p<0.05). WRW4 (FPR‐2 antagonist: 0.2 mg/rat), L‐NAME (NOS inhibitor: 15 mg/rat) and ODQ (guanylate cyclase (GC) inhibitor: 0.6 mg/rat) all abolished F‐MIT‐induced hypotension and cyclosporine H (FPR‐1 antagonist: CsH, 3 mg/rat) partially reduced this response. Also, isolated mesenteric resistance arteries were used to assess F‐MIT on vascular function. F‐MIT (10‐30 μM) induced relaxation (~30%) but ODQ or WRW4 abolished this response. However, L‐NAME (100 μM) or CsH (1 μM) only partially inhibited the vasodilatation. These data suggest that FPR‐2>FPR‐1 activation induces hypotension via NO. However, the vasodilatation induced by FPR‐2 is mediated by mechanisms that are NO‐independent but GC‐dependent. Thus, F‐MIT may be a link between trauma, sterile SIRS and sepsis.Grant Funding Source: Supported by NIH, CNPq and AHA
Sarcolipin orchestrates calcium signaling to regulate muscle metabolism (1162.1)
Authors: Pant Meghna , Sopariwala Danesh , Rafael‐Fortney Jill , Periasamy Muthu 
Published: June 2021

Sarcolipin(SLN) is 31 amino acid long protein that regulates the Sarcoplasmic reticulum calcium ATPase (SERCA) activity in skeletal and cardiac muscle. Recently, our lab identified that SLN plays an important role in muscle‐based thermogenesis. Mice lacking SLN are cold sensitive and susceptible to diet induced obesity. Interestingly SLN is induced in skeletal muscle during neonatal development, high fat diet, muscle dystrophies, and inflammation. Since these are the states of increased oxidative metabolism in skeletal muscle we hypothesize that SLN is recruited to maintain this oxidative phenotype. Here we show that SLN overexpressing muscle fibers have high resting calcium and increased recruitment of calcium mediated signaling when there is increased demand. To determine the mechanism regulating SLN induction and downstream signaling we made use of C2C12 cells. We show that inhibiting the calcium signaling pathways regulated by calcineurin downregulates the expression of SLN. Based on our data we propose that SLN forms a feedback loop with calcium mediated signaling pathways and plays an important role to support the oxidative metabolism in skeletal muscle.Grant Funding Source: Supported by NIH, MDA
Sarcolipin overexpression in mice increases their endurance exercise capacity (1162.2)
Authors: Sopariwala Danesh , Shaikh Sana , Pant Meghna , Rowland Leslie , Periasamy Muthu 
Published: June 2021

Sarcolipin (SLN) is a transmembrane protein that interacts with Sarco(endo)plasmic Reticulum Calcium ATPase (SERCA) and is expressed in cardiac and skeletal muscle. SLN is known to inhibit Vmax of SERCA, but its role in muscle physiology is yet to be fully understood. We have shed some light on this front, by showing that SLN knock out (SLN KO) mice are highly sensitive to acute cold and are prone to develop obesity when fed a high fat diet. Moreover, we showed that the SLN KO mice can be rescued from hypothermia by over expression of the SLN transgene; suggesting that SLN is essential for heat generation and increasing metabolic rate. The aim of this study was to further explore how SLN affects muscle function and metabolism; by the use of SLN over expression (SLN OE) mouse model, which expresses SLN in all skeletal muscles up to 10 fold higher than in wild type (WT) mice. Here, we show that SLN OE mice have a higher basal metabolic rate (by indirect calorimetry) than WT mice. The SLN OE mice also have a significantly higher endurance capacity (treadmill running) than their WT littermates. Isolated muscle studies using Tissue Oxygen bath system, show that SLN OE muscle has similar force frequency response as WT muscle, but is more resistant to develop fatigue and consumes more oxygen. Analysis of muscle oxidative metabolic markers and oxygraph measurements using isolated mitochondria; suggest an increased oxidative capacity in the SLN OE muscle compared to WT. Although skeletal muscle can increase metabolic rate up to hundred fold, a decline in the rate of ATP production is a major reason for muscle fatigue during prolonged physical activity. Hence, these results indicate that SLN enhances muscle’s ability to hydrolyze substrates and generate ATP in times of increased energy demand, which in turn increases endurance capacity.Grant Funding Source: Supported by NIH