bluuebunny/crossref_metadata_2025_split huggingface dataset:
Telomere‐independent Rap1 Induces Cytokine Production In Pro‐inflammatory Macrophages Through NFκB Signaling
Authors: CAI Yin , VANHOUTTE Paul M. , TANG Eva H.C. 
Published: November 2023

Repressor activator protein 1 (Rap1), an established telomere‐associated protein, is essential for maintaining telomere length and structural integrity, but it also exerts other non‐telomeric functions. The present study tested the hypothesis that Rap1 is released into the cytoplasm and induces production of pro‐inflammatory cytokines via nuclear factor kappa B (NFκB) signaling in macrophages, a cell type involved in the development and progression of atherosclerotic lesions. Western blotting analysis confirmed that Rap1 was present in the cytoplasm of differentiated human monocytic leukemia cells (THP‐1, a macrophage‐like cell line). Co‐immunoprecipitation assay revealed a direct interaction between Rap1 and I kappa B kinase (IKK). Knockdown of Rap1 significantly suppressed lipopolysaccharide‐mediated activation of NFκB (by 39.0%), and phosphorylation of inhibitor of kappa B α (IκBα) and p65 in THP‐1 macrophages (by 52.7% and 32.0%, respectively). The reduction of NFκB activity was paralleled by a decreased production of NFκB‐dependent pro‐inflammatory cytokines [including interleukin (IL)‐8, IL‐1β and monocyte chemotactic protein‐1] and an increased expression of IκBα (native NFκB inhibitor) in various macrophage models with pro‐inflammatory phenotype, including THP‐1, mouse peritoneal macrophages and bone marrow‐derived M1 macrophages. These changes were observed selectively in pro‐inflammatory macrophages but not in bone marrow‐derived M2 macrophages (with an anti‐inflammatory phenotype). Furthermore, in human atheroma, endothelial and smooth muscle cells elaborate cytokines and contribute to the overall inflammatory environment. However, knockdown or knockout of Rap1 does not influence the expression of NFκB‐dependent targets in human umbilical vein endothelial cells, human aortic smooth muscle cells or mouse lung endothelial cells. Immunostaining revealed that Rap1 was localized mainly in macrophage‐rich areas rather than in endothelial or smooth muscle cell‐rich areas in human atherosclerotic plaques and that the presence of Rap1 was positively correlated with the advancement of the disease process. In conclusion, in pro‐inflammatory macrophages, Rap1 promotes cytokine production via NFκB activation favoring a pro‐inflammatory environment which may contribute to the development and progression of atherosclerosis.Support or Funding InformationThis study was supported by National Natural Science Foundation of China (NSFC 81270383).
Norepinephrine Protects Cerebral Autoregulation and Reduces Hippocampal Necrosis after Traumatic Brain Injury via Block of ERK MAPK and IL‐6 in Juvenile Pigs
Authors: Armstead William , Riley John , Vavilala Monica 
Published: November 2023

Traumatic brain injury (TBI) contributes to morbidity in children, and boys are disproportionately represented. Cerebral autoregulation is impaired after TBI, contributing to poor outcome. Cerebral Perfusion Pressure (CPP) is often normalized by use of vasoactive agents to increase mean arterial pressure (MAP). In prior studies of 1–5 day old newborn piglets, we observed that norepinephrine (NE) preferentially protected cerebral autoregulation and prevented hippocampal necrosis in females but not males after fluid percussion injury (FPI). The ERK isoform of mitogen activated protein kinase (MAPK) produces hemodynamic impairment after FPI, but less is known about the role of the cytokine IL‐6. We investigated whether NE protects autoregulation and limits histopathology after FPI in older juvenile (4 week old) pigs and the role of ERK and IL‐6 in that outcome by sex. Results show that NE significantly protects autoregulation and prevents reduction in CBF in both male and female juvenile pigs after FPI; co‐administration of the ERK antagonist U 0126 with NE fully protects both indices of outcome. Papaverine induced dilation was unchanged by FPI and NE. NE blunted ERK MAPK and IL‐6 upregulation in both males and females after FPI. NE attenuated loss of neurons in CA1 and CA3 hippocampus of males and females after FPI. These data indicate that NE protects autoregulation and limits hippocampal neuronal cell necrosis via block of ERK and IL‐6 after FPI in both male and female juvenile pigs. These data suggest that use of NE to improve outcome after TBI is both sex and age dependent.Support or Funding InformationNIH R01 NS090998
Cerebrovascular vasoconstrictor responses in young and older adults: effect of age and exercise
Authors: Miller Kathleen B , Harvey Ronee E , Joyner Michael J , Barnes Jill N 
Published: November 2023

Recent research focuses on the cerebrovascular response to vasodilatory stimuli as an index of cerebrovascular health; however, vasoconstrictor responses in the brain are likely equally important. We previously have shown that cerebral vasoconstrictor responses to hypocapnia are not affected by aging; however, this was evaluated in primarily sedentary adults. Therefore, we hypothesized that middle cerebral artery velocity (MCAv) vasoconstrictor responses to hypocapnia are dependent on age and habitual physical activity. We evaluated 13 young physically active (YA; age = 30±5 y; VO2max = 45±8 mL/kg/min), 6 young sedentary (YS; age = 29±4 y; VO2max = 26±3 mL/kg/min), 10 older physically active (OA; age= 61±6 y; VO2max =35±7 mL/kg/min) and 8 older sedentary (OS; age = 65±8 y; VO2max 23±2 mL/kg/min) adults during the recovery from inhaled 6% CO2 to room air. Mean arterial pressure (MAP) end tidal CO2 (ETCO2) and MCAv were recorded throughout. Using a breath‐by breath analysis, cerebrovascular conductance index (CVCi=MCAv/MAP) reactivity was calculated as a slope of CVCi and ETCO2 and used to quantify vasoconstrictor responses. CVCi reactivity was higher in YA adults (slope=2.74±0.9 AU) compared with both YS (slope=2.20±1.1 AU) and older groups (OA: slope=2.08±0.5 AU; OS: slope=2.07±0.7 AU; p<0.05 for all). There were no significant differences in CVCi reactivity between YS and either OA or OS (p=0.94, p=0.99 respectively). Additionally, CVCi negatively correlated with age (r=−0.38, p<0.05). Our results indicate that aging attenuates the cerebral vasoconstrictor response to hypocapnia in older adults in comparison to physically‐active young adults, but not compared to sedentary young controls. A sedentary lifestyle resulted in attenuated vasoconstrictor responses in the young sedentary group, as their responses were not different than the older adults. It remains unclear how habitual physical activity preserves the cerebral vasoconstrictor response to hypocapnia in young people, and if a structured exercise training intervention would impact this response in older adults.Support or Funding InformationNIH HL118154
Implications of Electrical Communication in Brain Blood Flow Regulation and Stroke Injury
Authors: Zechariah Anil , Tuor Ursula I , Welsh Donald G. 
Published: November 2023

An integrated network of cerebral arteries actively coordinates brain blood flow in accordance with metabolic demands. Large regional changes require synchronised vasomotor responses across vessel segments starting at the origin of a stimulus and spreading to the major upstream resistors. The coordination of vasomotor tone is intimately tied to the spread of charge through gap junctions, a process that equalizes membrane potential, [Ca2+] and myosin light chain phosphorylation among thousands of smooth muscle cells. Coordinated responses are critically important during cerebrovascular accidents (i.e. stroke) where the synchronized dilation of collateral vessels diverts flow into ischemic tissue. We hypothesized that electrical communication, via gap junctions, plays a central role and that dysfunctional communication between vascular cells impairs collateral responses, increasing stroke injury. Using isolated cerebral arteries from mouse, hamster and resected human tissue, we show that electrical stimuli can effectively spread along vascular cells in an endothelium dependant manner. Genetic deletion of Connexin40 (Cx40−/−), a component protein of gap junctions, compromised electrical communication in the cerebral arteries. Subjecting Cx40−/− mice to focal cerebral ischemia induced greater deficit in cerebral blood flow than in wild type controls, during stroke and the subsequent reperfusion period. This attenuation of blood flow translated to augmented stroke injury in the Cx40−/− mice. In closing, our study illustrates the presence of robust electrical communication and that compromising this integrated process restricts the ability of the cerebral circulation to respond to, and moderate injury from vascular accidents, including stroke.Support or Funding InformationThis work is supported by an operating grant to Dr Welsh from the Natural Science and Engineering Council of Canada (NSERC). Dr Welsh is the Roraback Chair in Neuroscience and Vascular Biology at the University of Western Ontario. A. Zechariah is supported by Canadian Institutes of Health Research (CIHR) Postdoctoral scholarship, Alberta Innovates Postdoctoral scholarship and Eyes High Postdoctoral fellowship. Dr. Tuor is supported by a grant from CIHR.
Differential wall shear stress patterns in cerebral circulation of prediabetic adults: Possible evidence for increased stroke risk?
Authors: Aleckson Benjamin P , Kellawan Mikhail , Harrell John W. , Schrauben Eric M. , Hoffman Carson A. , Roldan‐Alzate Alejandro , Wieben Oliver , Schrage William G. 
Published: November 2023

Proper endothelial function is crucial to cerebral vascular health and is affected by wall shear stress (WSS) patterns. Metabolic syndrome (MetSyn) is a prediabetic state that contributes to endothelial dysfunction which can lead to clinical conditions, such as, stroke. The aim of this study was to quantify and compare resting WSS in multiple conduit cerebral arteries in healthy and MetSyn subjects. We hypothesized adults with Metsyn will display reduced WSS in cerebral arteries when compared to healthy controls. 7 healthy controls (29±2y) and 7 MetSyn (37±3y) underwent a single four‐dimensional (4D) flow MRI scan during quiet rest in the supine position. Data acquisition was based on a radial undersampling scheme named Phase Contrast Vastly‐undersampled Isotropic Projection Reconstruction (PC VIPR) used to generate a phase contrast (PC) angiogram, as well as, measure cerebral blood flow (CBF), and WSS non‐invasively without use of a contrast agent (three directional velocity encoding at a spatial and temporal resolution of 0.68 mm and 20 cardiac phases, respectively). Average scan time was ~ 5 minutes and produced large imaging volumes. Nine arteries were analyzed: Middle cerebral (MCA) ×2, anterior cerebral (ACA) ×2, internal carotid (ICA) ×2, vertebral (VA) ×2, and basilar. WSS was measured by segmenting the vascular tree from the PC angiograms and subsequently calculating the velocity gradient at the vessel wall from the 4D Flow MRI data over ~ 3 voxels. Total CBF was calculated as the sum of the left and right ICA and basilar artery. Resting total CBF was 577±45 ml· min−1 in healthy controls and 499±46 ml ·min−1 in MetSyn (p=0.25). Metsyn exhibited lower WSS (Pa) in the left MCA (3.7±0.2 vs. 3.0±0.2; p=0.01), right ACA (3.4±0.2 vs. 2.9±0.2; p=0.05), right ICA (2.7±0.3 vs. 1.8±0.1; p=0.01) and left ICA (2.8±0.3 vs. 1.5±0.1; p<0.01). This non‐invasive MRI approach provides new insight into local flow and shear patterns that might have a large impact on cerebral endothelial function. Younger adults with MetSyn exhibit lower WSS in anterior portions of the brain. Furthermore, these findings are consistent with the observation that stroke occurs most commonly in the anterior cerebral circulation. Given the young age (< 45 y) of these subjects, we propose chronically reduced WSS leads to endothelial dysfunction in middle/old age, thereby contributing to increased risk and severity of stroke in MetSyn.Support or Funding InformationFunded by the American Diabetes Association and an American Physiological Society Undergraduate Research Summer Fellowship.
Heparin's Anti‐Inflammatory Effects in Vascular Endothelial Cells are Mediated Through Transmembrane Receptor 184A
Authors: Farwell Sara Lynn Nicole , Lowe‐Krentz Linda 
Published: November 2023

The glycosaminoglycan heparin has been used as an anti‐coagulant in the treatment of cardiovascular diseases for decades. The mechanism of heparin binding to enzyme inhibitor antithrombin III in the coagulation cascade has been well‐documented. Heparin has also been shown to illicit anti‐proliferative and anti‐inflammatory responses in vascular cells, though mechanism(s) remain unclear. Recently we have used antibodies that mimic heparin effects in vascular smooth muscle cells to identify transmembrane protein 184A (TMEM184A) as a putative heparin receptor. The objective of this study was to investigate TMEM184A expression and function in vascular endothelial cells. We observed TMEM184A expression in cultured endothelial cells and in the zebrafish caudal fin vasculature through immunofluorescence using commercial antibodies against a region near the N‐terminus and a region of 20 amino acids of an internal region. To determine whether heparin effects on inflammatory responses were mediated through TMEM184A, rat aortic endothelial cells (RAOECs) were electroporated with control or TMEM184A shRNA. Control and knockdown RAOECs were treated with 200 μg/ml heparin for 20 min, followed by 25 ng/mL TNFα. Quantitative immunofluorescence of activated JNK or p38 showed that heparin treatment prior to TNFα significantly decreased JNK and p38 activation in control shRNA cells compared to cells treated with TNFα alone. However, in TMEM184A knockdown cells, heparin pre‐treatment did not decrease JNK or p38 activation. Heparin induction of DUSP1 was found to be critical for these effects. In control ECs, heparin pre‐treatment decreased TNFα‐induced stress fiber formation. To investigate whether TMEM184A was also necessary for these effects, stress fibers were quantified through immunofluorescence. In TMEM184A knockdown RAOECs, heparin pre‐treatment did not decrease TNFα‐induced actin stress fiber formation. In conclusion, our results show that TMEM184A is expressed specifically in the vasculature in vitro and in vivo. We provide functional evidence that anti‐inflammatory effects of heparin are dependent at least in part on TMEM184A. Further investigation of heparin's anti‐inflammatory effects through TMEM184A in the vasculature is crucial for developing and improving therapeutic strategies in vascular disease.Support or Funding InformationThis work was supported by NIH grant HL54269 to LLK
Microgravity‐Induced Activation of Nlrp3 Inflammasomes in Mouse Vascular Endothelial Cells
Authors: Xia Min , Nguyen Thaison P , Bao Jun‐Xiang , Meng Nan , Boini Krishna M , Li Pin‐Lan 
Published: November 2023

In the microgravity environment, astronauts usually have cardiovascular deconditioning, even endothelial dysfunction that may initiate or accelerate coronary heart disease. Although pro‐inflammatory cytokines were reported to increase in microgravity, which may lead to inflammation, the underlying molecular mechanism instigating this microgravity‐induced inflammation remains poorly understood. In the present study, we tested whether microgravity activates Nlrp3 inflammasomes in endothelial cells (ECs) and thereby turns on vascular inflammation. By confocal microscopy and 3D culture of mouse ECs in rotating wall vessel bioreactor to generate microgravity (MG), we detected the enhancement of co‐localization of Nlrp3 with apoptosis‐associated speck‐like protein (ASC) or with caspase‐1 when ECs were exposed to MG. Biochemical analyses revealed that MG significantly increased the cleavage of procaspase‐1 into active caspase‐1 and enhanced caspase‐1 activity (1.3 folds) and IL‐1β production (2.6 folds) in ECs compared to those cells under normal gravity (NG). The formation of active caspase‐1 was inhibited by a potassium ion (K+) channel blocker, glibenclamide, but not affected by antioxidant N‐acetyl‐L‐cysteine (NAC) or cathepsin B inhibitor, CA‐074 methyl ester. In addition, we found that more ceramide‐enriched macrodomains or platforms on the plasma membrane were observed in ECs under MG compared to cells under NG. These results suggest that MG leads to activation of Nlrp3 inflammasomes in ECs through a K+ efflux and ceramide‐enriched membrane platform formation. This activation of Nlrp3 inflammasomes may represent a novel initiating mechanism to produce the inflammatory response and endothelial dysfunction during MG.Support or Funding InformationSupported by NIH grants HL057244, HL075316, HL091464 and HL122937
Organ Targeted Copper Delivery Reverses Fibrosis in Rhesus Monkey Model of Myocardial Ischemic Infarction
Authors: Xiao Ying , Nie Xin , Han Pengfei , Kang Y. James 
Published: November 2023

Excessive collagen deposition post myocardial ischemic injury hastens heart failure. Copper supplementation significantly improved cardiac function and reduced fibrosis in myocardial ischemic infarction. The present study was undertaken to understand the link between the reduced fibrosis and the recovery of cardiac function. Male Rhesus monkeys of 4–5 years old were subjected to coronary artery ligation to induce myocardial infarction. At the end of fourth weeks after the surgery, ultrasound contrast microbubble composed of Cu‐albumin coating for cardiac organ‐specific Cu delivery through ultrasound manipulation was used to treat the monkeys twice a week for other four weeks. Collagen deposition in the infarct hearts was observed 4 weeks and further enhanced 8 weeks after ischemia. The collagen content in the infarct myocardium was not changed significantly after Cu treatment. However, type I and III collagen mRNA levels were decreased, and collagen network became loosened, along with an increase in the capillary density. Lysyl oxidase (LOX), an enzyme related to collagen deposition, was increased, and metalloproteinase‐1 (MMP‐1), an enzyme involved in collagen degradation, was decreased in the infarct area relative to sham operated control and remote area. After Cu treatment, MMP‐1 was significantly increased, and the ratio between MMP‐1/LOX was dramatically elevated. These results thus suggest Cu‐induced MMP‐1 elevation in the infarct area is mostly likely responsible for the breakage of collagen cross‐linking leading to diminished collagen deposition and improved angiogenesis and recovery of cardiac function.Support or Funding InformationThis study is supported by National Science Foundation of China (81230004 and 81300109).
Left Ventricular Hypertrophy Is Associated With Decreased α But Not β‐Myosin Gene Expression in Spontaneously Hypertensive Nonhuman Primates
Authors: Weaver Chelsea Christina , Gutierrez Anthony , Osborn Jeffrey L 
Published: November 2023

Essential hypertension (EH) is associated with increased risk of cardiovascular disease and heart failure. Left ventricular hypertrophy (LVH) also increases the risk of heart failure yet the mechanisms underlying ventricular cardiac remodeling remain unclear. The vervet monkey (Chlorocebus aethiops sabaeus) is a highly translational model of hypertension as they share more than 97% of their genome with humans and naturally develop spontaneous hypertension. We have identified vervets from outbred colonies as either hypertensive (HT, systolic blood pressure, SBP≥140 mmHg) or normotensive (NT, SBP<120 mmHg) using forearm plethysmography under ketamine sedation (15 mg/kg i.m.). We hypothesize that in the vervet, spontaneous hypertension is associated with LVH combined with altered gene expression of myocardial contractile proteins and pro‐inflammatory agents similar to other dietary, surgical pathology or pharmacological induced models of hypertension in quadripedal mammals. Cardiomyocyte cross‐sectional area of left but not right ventricles was greater in HT than NT individuals (HT 1658μm2±515, n=6 vs. NT 791μm2±210, n=7; p<0.01) demonstrating significant morphological LVH in this model of spontaneous hypertension. Semi‐quantitative RT‐PCR assessed left ventricular α/β myosin gene expression of HT (mean SBP=171.5±7.3 mmHg; n=15) and NT (mean SBP 98.9±2.4 mmHg; n=14) vervets. Gene expression in left ventricular myocardium was normalized using reference gene RPS13A. α‐myosin was downregulated in HT versus NT vervets (HT RQ=0.10±0.03 vs. NT RQ=0.22±0.04; p<0.05), whereas β‐myosin expression was not different (HT RQ=0.22±0.17 vs. NT RQ=0.20±0.16; p=0.83). The LVH pro‐inflammatory intracellular adhesion molecule 1 (ICAM‐1) gene expression also was measured using RNA extracted from left ventricular myocardium. ICAM‐1 gene expression in HT and NT vervets was not different (HT RQ=0.11±0.03 vs. NT 0.15±0.07; p=0.47). We conclude that downregulation of α‐myosin in the left ventricular myocardium in HT vervets may represent the early onset stages of the shift of α to β myosin characteristic of long‐term LVH and established heart failure after chronic elevation of systemic vascular resistance and blood pressure. At present, pro‐inflammatory ICAM‐1 is not associated with development of LVH in HT vervets. Future studies will further divide nonhuman primate groups into HT with LVH, HT without LVH, and NT to more selectively evaluate molecular protein expression with myocardial hypertrophy in spontaneous hypertension as well as the expression of additional inflammatory cytokines within the myocardium.Support or Funding InformationSupported by Biomedical Sciences Research Group, L.L.C.
Evaluation of biological and mechanical variations in hypertensive animal models
Authors: Lue Sheng‐I , Zhuang Jun‐Cheng , Fu Yaw‐Syan , Lu Tzongshi 
Published: November 2023

Introduction and HypothesisHypertension (HT) is a multifactorial cardiovascular disorder involves in variety genetic and environmental factors. To properly study the pathophysiology of hypertension, robust and reproducible experimental animal models are required. The ideal HT animal model should have human‐like cardiovascular anatomy, hemodynamics, and physiology that includes genetic and non‐genetic models. Among these HT animal models, Spontaneously Hypertensive Rats (SHR) with both neural and vascular alterations is the most commonly used genetic HT animal model. In this study, we investigated methodical variations among current HT animal models.MethodsHistamine, Capsaicin, C48/80 or Substance P were administered into the femoral vein of Sprague Dawley rats or SHR to induce endothelial dysfunction. We analyzed mean arterial pressure and analyze plasma extravasation using Evans Blue dye. One way ANOVA with Bonferroni correction, and linear regression were used for statistics. Statistical significances were set at a P< 0.05.ResultsOur data showed significant negative linear regression on the degree of plasma extravasation with blood pressure changes in neurogenic inflammation but positive linear regression in immunogenic inflammation. In addition, Evans blue dye inhibited C48/80‐induccd extensive plasma extravasation, mast cell degranulation, and edema significantly.ConclusionsWe have observed significant variations among neurogenic and immunogenic inflammation induced blood pressure changes. Our data shows for the first time that methodical variations observed among animal models, can potentially translate into differential blood pressure patterns, which can be falsely taken to be biologically significant. Our study therefore highlights the pivotal need to carefully consider methodical approaches to animal models that report quantitative differences.