bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mathematical Model of Calcium and Electrical Dynamics in Lymphatic Endothelium
Authors: Jafarnejad Mohammad , Behringer Erik J , Scallan Joshua P , Davis Michael J , Segal Steven S , Moore James E 
Published: November 2023

Contraction of collecting lymphatic vessels is essential for immunity and tissue fluid balance. The underlying role of lymphatic endothelium is unknown. In contrast to blood vessels, lymphatic endothelial cell tubes (LECTs; mouse popliteal fossae) do not govern membrane potential (Vm) via small‐ and intermediate‐conductance Ca2+ activated K+ channels (SKCa/IKCa). Consequently, despite similarity in the intracellular Ca2+ ([Ca2+]i) response to acetylcholine (1 μM) (i.e., rapid initial peak followed by secondary “plateau” phase), depolarization of Vm (ΔVm: 29±4 mV, n=11 LECTs) ensues in contrast to classic hyperpolarization in blood vessels (ΔVm: −38±3 mV, n=4 popliteal arteries). To further resolve the contribution of respective ions and channel [e.g. transient receptor potential (TRP)] currents to LECT depolarization, we adapted mathematical models of [Ca2+]i dynamics and ion fluxes (e.g., Hodgkin‐Huxley). Modeling reproduced [Ca2+]i responses and accompanying depolarization observed experimentally. Furthermore, depolarization required a combination of Na+ and Ca2+ influx via cation membrane channels (e.g., TRP canonical & vanilloid 4, Orai) during the plateau phase. Roles of other ions (e.g., K+, Cl−) and respective channels (e.g., inward‐rectifying K+ & volume‐regulated anion) were also apparent. Altogether, the absence of SKCa/IKCa function during robust Na+ and Ca2+ mobilization determines the electrical activity of lymphatic endothelium. Such novel cellular signaling may regulate the efficacy of lymphatic muscle cell activity to control lymph transport during health while disruption of these interactions may contribute to disease.Support or Funding InformationNIH grants R01 HL094269, U01 HL123420 (JEM), R01 HL120867 (MJD), R37 HL041026 (SSS), K99/R00 AG047198 (EJB), K99 HL124142 (JPS); The Royal Society, The Royal Academy of Engineering, and The Sir Leon Bagrit Trust (JEM).
Endothelial nitric oxide synthase protein distribution in endothelial cells along the coronary vascular tree
Authors: Israel Jessica H , Bray Jeffrey F , McIntosh Avery L , Schroeder Friedhelm , Heaps Cristine L 
Published: November 2023

Previous investigations have compared the levels of endothelial nitric oxide synthase (eNOS) protein among different branch orders of the coronary arterial tree. In these studies, eNOS protein levels were determined in whole vessels and thus were likely influenced by variable amounts of non‐endothelial cell types in the lysate as vessel wall thickness varied. For the current study, we isolated endothelial cells from both coronary conduit arteries and microvasculature to test the hypothesis that the content of eNOS protein remains similar in coronary endothelial cells regardless of vessel radius. Porcine hearts were obtained from a local abattoir and transported to the lab in iced Krebs solution. Large (conduit) and small arteries as well as arterioles were dissected free of myocardium and homogenized as whole vessels. Additionally, endothelial cells were isolated from both conduit arteries and left ventricular myocardium by mincing the tissue into small pieces, digesting with collagenase, followed by endothelial cell isolation using biotinylated‐anti‐CD31 and streptavidin‐coated paramagnetic beads. Purity of isolated coronary endothelial cells was confirmed by immunofluorescence and immunoblot. In whole vessel lysate, immunoblot analysis revealed that protein content for eNOS was significantly greater in arterioles compared to small arteries and large arteries. In contrast, eNOS protein levels in endothelial cells isolated from coronary microvasculature were not significantly different from those isolated from large conduit arteries. Taken together, these data indicate that endothelial cell eNOS protein content is comparable regardless of whether endothelial cells are isolated from the coronary microcirculation or conduit arteries. Furthermore, use of whole vessel lysate among different branch orders to compare levels of endothelium‐specific proteins may be unsuitable due to variable contamination by other cell types.Support or Funding InformationNIH R01‐HL064931
Whole Brain Irradiation Impairs Cerebromicrovascular Function and Promotes Cognitive Decline: Potential Role of Endothelial Senescence
Authors: Yabluchanskiy Andriy , Hertelendy Peter , Ashpole Nicole M , Tarantini Stefano , Logan Sreemathi , Owen Daniel B , Farley Julie A , Ungvari Zoltan , Sonntag William E , Csiszar Anna 
Published: November 2023

Whole brain irradiation (WBI) leads to a progressive cognitive dysfunction in up to 50% of tumor patients surviving long‐term after treatment, due to, at least in part, γ‐irradiation induced cerebromicrovascular injury. Moment‐to‐moment adjustment of cerebral blood flow (CBF) via neurovascular coupling has a critical role in maintenance of healthy cognitive function. To determine whether cognitive decline induced by WBI associates with cerebrovascular dysfunction and neurovascular un‐coupling, C56BL/6J mice (3 mo) subjected to fractionated WBI (5Gy twice weekly for 4 weeks) and control mice were compared. Mice were tested for spatial memory performance (radial arm water maze), neurovascular coupling, endothelial function, and were sacrificed for molecular and immunohistochemical (IHC) analyses 90 days post‐irradiation. Mice with WBI showed impaired performance in the radial arm maze (increased path length vs control; p<0.05). WBI significantly decreased endothelium‐mediated CBF responses (laser Doppler flowmetry) in the somatosensory cortex evoked by contralateral whisker stimulation. In cultured cerebromicrovascular endothelial cells, γ‐irradiation induced replicative senescence and acquisition of a senescence‐associated secretory phenotype (SASP). In the mouse brain, WBI resulted in up‐regulation of the senescence‐associated genes, including Cdkn2a (p16INK4a), Serpine1 (PAI‐1), and the SASP genes Mcp2, IL6, IL1b (qPCR). IHC analysis revealed that the DNA damage marker H2AX was co‐localized with CD31 positive cells in sections from WBI mice. Collectively, our findings provide evidence for persistent neurovascular un‐coupling, highlighting the potential role of endothelial senescence in cerebromicrovascular dysfunction and cognitive decline induced by WBI.Support or Funding InformationThis study is supported by the Donald W. Reynolds Foundation and NINDS grant NS056218‐08 to WES.
Orphan Nuclear Receptors Nur77 and Nor1 Are Novel Regulators of Thrombotic Function in Vascular Endothelial Cells
Authors: Wei Xin , Yang Ping , Zhang Jian , Yi Bing , Zhang Guanxin , Yin Litian , Sun Jianxin 
Published: November 2023

ObjectiveThrombomodulin (TM) is highly expressed on the lumenal surface of vascular endothelial cells (ECs) and possesses potent anticoagulant, anti‐fibrinolytic, and anti‐inflammatory activities in the vessel wall. However, the regulation of TM expression and function in ECs remains largely unknown.Approaches and ResultsIn the present study, we characterized the nuclear receptor 4A (NR4A) family as a novel regulator of TM expression in vascular ECs under both basal and inflammatory conditions. We demonstrate that both NR4A receptor Nur77 and Nor1 robustly increase TM mRNA and protein levels in human vascular ECs and in mouse liver tissues after adenovirus‐mediated transduction of Nur77 and Nor1. Moreover, Nur77 gene deficiency and knockdown of Nur77 and Nor1 expression markedly attenuated the basal and VEGF‐stimulated TM expression in ECs. Mechanistically, we found that Nur77 and Nor1 increase TM expression by acting through two different mechanisms. We show that Nur77 barely affects TM promoter activity, but significantly increases TM mRNA stability, while Nor1 enhances TM expression mainly through induction of Kruppel‐like factor 2 and 4 in vascular ECs. Furthermore, we demonstrate that both Nur77 and Nor1 significantly increase the protein C activity and inhibit tumor necrosis factor alpha (TNF‐α)‐induced prothrombotic effects, at least in part, through an inhibition of the NF‐κB activation in vascular ECs. Moreover, in a model of ferric‐chloride‐induced carotid artery thrombosis, Nur77 deficiency markedly exacerbates the formation of arterial thrombosis, whereas the bleeding time was not affected.ConclusionsOur observations for the first time identified NR4A receptors Nur77 and Nor1 as novel regulators of TM expression and function in vascular ECs. We postulate that targeted increasing expression of Nur77 and Nor1 in vascular endothelium may represent a novel therapeutic approach for the treatment of vascular disorders, such as thrombosis and inflammation.Support or Funding InformationThis research was supported by the US National Institutes of Health (HL103869).
Process of cell‐free layer formation after arteriolar bifurcation and its physiological effects
Authors: Kim Sangho , Ng Yan Cheng 
Published: November 2023

Understanding the formation of cell‐free layer (CFL) in arteriolar networks has been of great interest, particularly for its significance in regulation of blood flow. The heterogeneous distribution of red blood cells (RBCs) modulated by the formation of CFL in arteriolar bifurcations potentially leads to alterations in tissue oxygenation (O2) and vascular tone due to varying nitric oxide (NO) production in the endothelium. Accordingly, we investigated the formation of CFL from 2 to 6 vessel‐diameter (2D–6D) downstream of arteriolar bifurcations in the rat cremaster muscle under reduced flow conditions (pseudoshear rates = 15.6 ± 2.0 s−1). We accounted for the spatiotemporal variations in the wall shear stress, velocity profile and core hematocrit along the downstream vessels by extending our previous image‐based two‐dimensional transient model, which was unprecedented in previous computational models. Our experimental results showed that an asymmetric formation of CFL width along the vessel walls was evident up to 6D from the bifurcating point. The recovery of CFL symmetry appeared to be impeded by RBC aggregation. Our numerical prediction of soluble guanylate cyclase (sGC) activity revealed that vasoactivity might not occur uniformly within an inter‐bifurcation distance, in particular under reduced flow and aggregating conditions.Support or Funding InformationNUS FRC
p66 Shc Contributes to Susceptibility to Cerebrovascular Injury and Intracerebral Hemorrhages
Authors: Beyer Andreas M. , Ait‐Aissa Karima , Miller Bradley , Sorokin Andrey 
Published: November 2023

BackgroundBreakdown of the blood brain barrier (BBB) and loss of cerebral vessels autoregulation in response to elevated systemic pressure are closely linked to intracerebral hemorrhage and micro bleeds. Presently no established models to study the causes of intracerebral hemorrhage exist that does not rely on surgical interventions and existing models have failed to improve clinical understanding of this condition. Overproduction of reactive oxygen species (ROS) following ischaemia/reperfusion (I/R) is considered a key mechanism leading to BBB damage. It has been shown that the adaptor protein p66(Shc) is crucial regulator for ROS production in several disease states including I/R injury of the brain. p66shc when activated translocates to the mitochondria where it sequesters cytochrome C and generates hydrogen peroxide. The contribution of mitochondria to myogenic tone and autoregulation of the cerebral vasculature is not well defined.We have found previously that rats expressing constitutively active form of p66 Shc (Shc‐CA) have decreased long term survival and increased incidences of stoke despite no significant difference in systemic blood pressure.HypothesisWe hypothesis that p66Shc signaling via mitochondrial translocation contribute to vascular dysfunction of cerebral arteries and intracerebral hemorrhage in hypertensive rats by decreasing mitochondrial ATP while elevating mitochondrial ROS.ResultsVessels from WT rats, lacking p66 Shc protein (Shc‐KO), or expressing Shc‐CA were used for video microscopy. Endothelial dependent dilation to flow was assessed in vessels from Shc‐KO animals compared to their littermate controls (%Max Dilation 100 cm H2O: WT = 1.3±3 vs. Shc‐KO=39±3*; N≥3 P<0.05 one way ANOVA). Shc‐CA failed to develop tone spontaneously or to pharmacological stimuli (as a result no dilator function could be studied) suggesting a defect in vascular smooth muscle function. No difference in tone were observed in WT vs. Shc‐KO. Further evaluation revealed loss of myogenic tone in MCAs of Shc‐CA (% Tone at 150 cm H2O relative to Ca2+ free: WT = 19±6; Shc‐KO = 28±12; Shc‐CA =3±2, n≥2). In vivo cerebral vascular flow was evaluated using Doppler laser probe and revealed an inability of cerebral vessels to respond to altered systemic pressure in vivo. Shc‐CA showed decreased levels of ATP (pmol/mg Protein WT=1±0.2; Shc‐KO=0.7±0.2; Shc‐CA=0.1±0.1*; N≥3 P<0.05 one way ANOVA) and mitochondrial respiration, confirming decreased mitochondrial function in rats that express Shc‐CA.To investigate an underling physiological relevance, rats were perfused with methylene blue (MB). A substantial increase in MB staining in the brain of Shc‐CA was observed, suggesting an increase in permeability of the BBB.
Effect of Age and High Fat Diet on the Pro‐Atherogenic Response to Oscillatory Blood Flow
Authors: Walker Ashley E , Breevoort Sarah R , Durrant Jessica R , Machin Daniel R , Dobson Parker S , Nielson Elizabeth I , Donato Anthony J , Lesniewski Lisa A 
Published: November 2023

Atherogenesis is more likely to occur in arteries at locations of greater oscillations in blood flow, such as branch points and curvatures. However, it is unknown if advancing age or a high fat diet affect the pro‐atherogenic response to increased oscillatory blood flow. To induce greater oscillatory blood flow, we performed partial carotid ligation (PCL) of the left carotid artery of young normal chow fed (YNC, 6.4±0.3 mo, n=10), young high fat fed (YHF, 6.0±0.2 mo, n=11), old normal chow fed (ONC, 29.0±0.1 mo, n=7), and old high fat fed (OHF, 29.7±0.3 mo, n=11) male B6D2F1 mice. After PCL, blood flow of the ligated (left) and control (right) carotids was measured by ultrasound. The pro‐atherogenic response was assessed in histological sections of carotids collected 3‐weeks post‐PCL by measurement of intima media thickness (IMT) and neointima formation. Additionally, a subset of histological samples were evaluated by a pathologist (n=3–5/group).After PCL surgery, antegrade blood flow was ~10‐fold less (p<0.001), but retrograde blood flow was not different between the ligated and control carotids (p>0.05). This resulted in an oscillatory index that was ~20‐fold higher in the ligated compared to the control carotids (p<0.001). Oscillatory index was not different between age or diet groups (p>0.05). Histological evaluation identified hypertrophied smooth muscle cells and separation of the mural elastic laminae in ligated carotids from all groups. On average, IMT was ~2 fold greater in the ligated carotid compared to the control carotid (p<0.001). Although IMT of the ligated carotid was not different between YNC and ONC mice (p>0.05), it was 52% greater in YHF compared to YNC (p<0.05) and 38% greater in OHF compared to ONC (p<0.05). Neointima formation in the ligated carotid was variable within groups and was primarily composed of smooth muscle cells and macrophages. Neointima was present in 20% of YNC, 45% of YHF, 14% of ONC, and 33% of OHF ligated carotids, but no neointima was present in control carotids from any group. In the ligated carotids, the percent of area within the internal elastic lamina composed of neointima was greater in YHF vs. YNC (19.5±7.4% vs. 4.3±2.8%, p<0.05) as well as in OHF vs. ONC (11.0±5.3% vs. 0.4±0.4%, p<0.05). The majority of YHF and OHF ligated carotids had adventitial or perivascular inflammation, extending into the media and intima in the most severe cases. However, minimal inflammation was present in YNC and ONC ligated carotids.In conclusion, we find a high fat diet, but not older age, leads to an exacerbated pro‐atherogenic response to increased oscillatory blood flow, indicated by greater IMT, neointima formation and vascular inflammation.Support or Funding InformationSupported by NIH AG046326, AG043952, AG040297, Department of Veterans Affairs 1I01BX002151
Differential effects of group III/IV skeletal muscle afferents and hypoxia on blood pressure during lower‐extremity dynamic exercise
Authors: Chantigian Daniel P , Cowl Andrielle L , Johnson Bruce D , Keller‐Ross Manda , Olson Thomas P 
Published: November 2023

Activation of group III/IV skeletal muscle afferents (ergoreflex) and hypoxia (chemoreflex) are two potent stimuli of the sympathetic nervous system during exercise. Venous distention by graded sub‐systolic occlusion contributes to the ergoreflex during exercise. Although the ergoreflex causes greater increases in blood pressure (BP) compared with the chemoreflex, the interaction of the ergoreflex and hypoxia during lower extremity dynamic exercise is unknown.ObjectiveTo determine the effect of hypoxia and graded cuff occlusion on hemodynamic responses during low‐intensity cycling exercise.Methods19 healthy adults (9 men, 25±5 yr) completed two sessions. Session 1 included a maximal cycle ergometry exercise test. Session 2 included two randomized bouts (hypoxia: 12.5% FiO2 and normoxia: 21% FiO2) of constant‐load cycling at 30% peak workload for 3 min (control, CTL) followed by randomized inflation of bilateral thigh pressure tourniquets to 20, 40, 60, 80, 100 mmHg for 2 min with 2 min of deflation between occlusions. The bouts were separated by 30 minutes of rest. Blood pressure, heart rate and cardiac output (CO) were measured continuously.ResultsDuring hypoxia, the average SPO2 was 80%. Venous occlusion and hypoxia had differential effects on mean arterial pressure (MAP, occlusion × hypoxia, p=0.02). Significant increases of MAP from CTL occurred at 60 (Δ9 ± 6mmHg), 80 (Δ15 ± 8mmHg), and 100mmHg (Δ17 ± 9mmHg) under normoxia (p<0.05). MAP only increased at 100mmHg (Δ14 ± 9mmHg) under hypoxia (p<0.05). Under hypoxia, MAP was much greater at CTL and 20mmHg as compared to normoxia (p<0.05). SBP exhibited responses similar to MAP under hypoxia (100mmHg increase, p<0.001, occlusion × hypoxia interaction, p=0.02). CO was greater with venous occlusion as mediated by increases in HR (p<0.001). In addition, CO increased under hypoxia (p=0.007) but had no interaction with venous occlusion.ConclusionDuring low pressure venous occlusion, hypoxia had a greater effect on BP, but as pressure increased (60–100mmHg), there were no significant differences in BP between normoxia and hypoxia. Therefore, sympathetically mediated increases of BP during exercise attributed to hypoxia may negate any responses mediated by the ergoreflex when elicited by venous occlusion at low pressures.
Smyd5 Regulates Hypertrophic Growth in the Heart
Authors: Anderson Alexa , Miller Mickey , Wang Li , Franklin Sarah 
Published: November 2023

Heart disease is the most financially debilitating and fatal disease between both men and women in the United States. Heart failure is defined as the point at which the heart's ability to function declines, due to overexertion, and can no longer sufficiently pump blood to vital organs throughout the body. While there are different forms of heart disease the pathophysiology of these is largely conserved: the heart compensates for an increased work load by undergoing hypertrophic growth and ultimately progresses onto heart failure. The Smyd family of histone methyltransferases has been studied for their involvement in cell growth during development and disease and is thought to accomplish this by regulating gene expression through histone methylation. While the roles of Smyd1, 2, and 3 are beginning to be defined, the remaining two family members, Smyd4 and 5, are virtually uncharacterized. My hypothesis is that Smyd5 is involved in inhibiting hypertrophic growth in the myocardium, however, its role in the heart is completely unknown. To determine the function of Smyd5, we generated constitutive and inducible, cardiac‐specific Smyd5 knockout mice and have characterized their cardiac phenotype under basal conditions and after stress (pressure‐overload hypertrophy and isoproterenol infusion). When compared to wild type mice, these animals display elevated heart weight/body ratios and left ventricular wall thickening as well as increased fibrosis and changes in fetal gene expression normally detected in cardiac hypertrophy. In addition knockout of Smyd5 significantly reduces methylation of lysine 20 on histone H4, suggesting a mechanistic basis for this phenotype. Together, our results show that although Smyd5 is dispensable for cardiac development, it is a critical regulator of hypertrophic cell growth and pathologic gene expression in the cardiomyocyte and highlights a novel role for this histone methyltransferase in the myocardium.Support or Funding InformationACCESS, BioURP, APS (UGREF), UROP, CVRTI
Dioscin improves heart function by increasing sodium influx via NCX in rat cardiomyocytes
Authors: Yin Yongqiang , Cong Tianshen , Yang Fan , Han Yu , Wen Ke , Kang Yi , Lou Jianshi 
Published: November 2023

ObjectiveDioscin (Dio) is widely used for the treatment of ischemic heart disease in China. The molecular mechanism underlying the inotropic effects of Dio, however, remains poorly understood.Methods and ResultsLeft ventricle contractile function was measured using the Langendorff non‐recirculating mode of isolated rat heart perfusion. Effects of Dio on cardiac function were assessed by measuring left ventricular systolic pressure (LVSP) and left ventricular end diastolic pressure (LVEDP) as well as the peak rate of rise/fall of left ventricular pressure (±dP/dtmax), in absence or presence of a sodium‐calcium exchanger inhibitor SEA0400. Our ex vivo data show that within the concentrations of 0.1–1μmol/L, Dio significantly increased the LVSP and +dP/dtmax, and these effects were significantly antagonized by 1 μmol·L−1 SEA0400. Furthermore, we investigated the effect of Dio on sodium current (INa) and L‐type calcium current (ICa,L). Intriguingly, the ICa,L was found to be inhibited by Dio, while the INa was augmented by Dio. The effect of Dio on contractile function and ICa,L appears to be contradictory. Therefore, we assessed the effect of Dio on the [Ca2+]i in H9c2 cells. Dio significantly increases the relative fluorescence intensity of intracellular calcium (n=8, P<0.01 vs control), which was partially attenuated by either SEA0400 or calcium‐free or sodium‐free extracellular fluid. Mitochondrial membrane potential was further detected with multifunctional microplate reader in order to determine whether Dio causes mitochondrial injuries. Our data show that Dio barely affected the mitochondrial membrane potential at the concentration of 0.1–1 μmol·L−1, while 10 μmol·L−1 dioscin results in a slight decrease in the mitochondrial membrane potential.ConclusionOur results demonstrate that Dio exerts the positive inotropic effect through elevating [Ca2+]i and increasing sodium influx and sodium‐calcium exchange via the Na+/Ca2+ exchanger (NCX) in rat cardiomyocytes.Support or Funding InformationSupported by Youth Project of Tianjin Natural Fundation (14JCQNJC13700) to Yongqiang Yin