bluuebunny/crossref_metadata_2025_split huggingface dataset:
Involvement of a Novel a1A‐Adrenergic Receptor‐Coupled Signaling Pathway in Cardiac Contractility
Authors: Mohl Marion , Xiao Xiao‐Hui , Prosser Hamish , Iismaa Siiri , Feneley Michael , Graham Robert 
Published: June 2021

In the heart under normal conditions the β1‐adrenergic receptors (ARs) predominantly regulate cardiac contractility, with the α1‐ARs playing a minor role. However, when the heart is compromised, e.g. during cardiac hypertrophy, the α1‐ARs play a more prominent role.Using a model of enhanced cardiac α1A‐AR signaling (α1A‐H) we identified a novel signaling pathway involved in cardiac contractility but not hypertrophy. This pathway involves α1A‐AR‐activated translocation of Snapin and the transient receptor potential channel 6 (TRPC6) to the plasma membrane to form a ternary complex with α1A‐AR. In CMs from adult α1A‐H and WT mice, the α1A‐AR‐Snapin‐TRPC6 complex results in increased [Ca2+]i with stimulation by the α1A‐AR specific agonist A61603, which is dose related and proportional to the level of receptor expression. Blockade of TRPC6 inhibited α1A‐AR‐mediated increases in cardiac contractility in WT and α1A‐H hearts. Given that this model of enhanced α1A‐AR activity displays robust hypercontractility but no hypertrophy, our data hold promise that targeting of the α1A‐AR‐Snapin‐TRPC6‐mechanism may allow dissection of pivotal cardiac phenotypes with imminent therapeutic perspectives.Sponsor: NHMRC
Pharmacological characteristics of ATI‐9242, a Novel Atypical Antipsychotic
Authors: Choppin Agnes , Lach Leang , Lee Alexander , Nunez Oscar , Becker Cyrus , Palme Monica P , Paliard Xavier , Druzgala Pascal , Jasper Jeffrey R 
Published: June 2021

ATI 9242 is a dibenzo(b,f)(1,4)oxazepine derivative designed with the goal of developing an oral drug that is effective for neuropsychiatric disorders with an improved side effect profile.The in vitro receptor profiling demonstrated that ATI 9242 has high affinity for 5‐HT2A and D2 receptor and submicromolar affinity for other dopamine (D1, D3, D4 and D5), serotonin (5‐HT1A, 5‐HT1B, 5‐HT1D, 5‐HT2B, 5‐HT2C, 5‐HT6 and 5‐HT7), histamine (H1) and alpha‐adrenergic (α1B and α2C) receptors.In cell‐based functional assays, ATI 9242 (10 μM) had no measurable agonist activity at dopamine (D1, D2S), histamine (H1), alpha‐adrenergic and serotonin (5‐HT2A, 5‐HT2B, 5‐HT2C, 5‐HT6 and 5‐HT7) receptors. At the 5‐HT1A receptor, ATI 9242 appeared to be a partial agonist (Ki=147 nM).ATI‐9242 prevented 5‐HT2A receptor‐mediated rat aortic ring contractions in a concentration‐dependent manner (ED50 = 3 nM), data consistent with the receptor binding results.In vivo, ATI 9242 exhibited an atypical antipsychotic‐like activity against apomorphine‐induced disruption of swimming in mice, but also in models of prepulse inhibition (PPI), without cataleptic effect (up to 30mg/kg IP), sedation (up to 10mg/kg IP), nor motor coordination impairment.Overall, the data presented herein indicate that ATI‐9242 is a novel atypical antipsychotic designed for multi‐target interactions with reduced side effects.
The effects of bosentan on thrombin‐activated fibroblasts and endothelial cells
Authors: Bogatkevich Galina S , Ludwicka‐Bradley Anna , Silver Richard M 
Published: June 2021

Endothelin‐1 and thrombin are elevated during lung injury and repair, as seen in scleroderma and other interstitial lung diseases, and each plays important roles in remodeling epithelium, blood vessels and connective tissue. Both factors promote myofibroblast differentiation, the hallmark of pulmonary fibrosis. Here we show that thrombin significantly induces endothelin‐1 expression in human lung fibroblasts. Bosentan, the dual, specific and competitive inhibitor of endothelin, significantly decreases α‐SMA, collagen gel contraction, and proliferation of human lung fibroblasts stimulated by thrombin, suggesting that thrombin‐induced differentiation of fibroblasts to the myofibroblast phenotype is at least in part regulated by endothelin‐1. Moreover, bosentan inhibits the basal level of fibroblast proliferation suggesting that endogenous endothelin may be in part responsible for fibroblast proliferation. The effect of bosentan on endothelial cells is concentration dependent. At concentrations of 10μM and 100μM bosentan inhibits thrombin‐induced endothelial cell migration and angiogenesis, whereas low‐dose (10nM) bosentan demonstrates a significant angiogenic effect. Bosentan rapidly phosphorylates Akt in endothelial cells and promotes cell survival. Our results demonstrate that low‐dose bosentan protects endothelial cells from apoptosis and increases their functionality. We conclude that bosentan may be a promising therapeutic agent in the treatment of microvascular injury as seen in scleroderma and other interstitial lung diseases.Study sponsor: Actelion Pharmaceuticals
Gcn5 Functions in Mammalian Development
Authors: Atanassov Boyko , Hirsch Calley , Dent Sharon 
Published: June 2021

We have created a series of mutations in the mouse Gcn5 gene in order to define the functions of this HAT in a mammalian system. Deletion of Gcn5 leads early embryonic death and to telomere dysfunction. Biochemical studies reveal that depletion of Gcn5 or ubiquitin specific protease 22 (Usp22), which is another bona fide component of the Gcn5‐containing SAGA‐type complex, increases the turnover of two shelterin proteins, TRF1 and POT1a. Inhibition of the proteasomes opposes this effect. The Usp22 deubiquitylating module requires association with SAGA complexes for activity, and we find that depletion of Gcn5 compromises this association in mammalian cells. Overall, these results indicate that Gcn5 regulates TRF1 levels through effects on Usp22 activity and SAGA integrity. These studies provide the first indication that Gcn5 and mammalian SAGA influence telomere maintenance and the first demonstration that SAGA affects protein stability. Current studies are directed at identifying additional USP22 targets.We have also created Gcn5 null ES cells. Upon removal of LIF, these cells lose pluripotency more quickly than do wild type ES cells. Preliminary data suggest that Gcn5 may be a key regulator of the master transcription factors required for maintenance of the pluripotent state.
Ankle Blood Pressure: A Novel Measure Affecting Central Arterial Wave Reflection?
Authors: Tarumi Takashi , Sugawara Jun , Tanaka Hirofumi 
Published: June 2021

ObjectiveThere is an increasing recognition that central aortic pressure is more relevant than peripheral (brachial) measure for the prediction and pathophysiology of cardiovascular disease. Central pressure is greatly influenced by the phenomenon of arterial wave reflections returning from the peripheral vasculature, which can be quantified by augmentation index. Primary wave reflections returning to the heart are thought to come from the lower body (e.g., lower limbs). Accordingly, the primary aim of the present study was to determine the association between central augmentation index and arterial blood pressures recorded in both the upper and lower limbs.MethodsA total of 1,189 apparently healthy adults (567 males and 622 females) of varying ages were studied. Brachial and ankle blood pressure, carotid augmentation index, and brachial‐ankle pulse wave velocity were measured.ResultsAll of the blood pressure (brachial and ankle, systolic, mean, and diastolic) measurements were significantly associated with carotid augmentation index. Among them, ankle mean arterial pressure was the strongest correlate of carotid augmentation index (r=0.56, P<0.05). This relation remained highly significant even after the influence of brachial blood pressure or age was accounted for in the partial correlation analyses. Moreover, stepwise regression analyses revealed that ankle mean arterial pressure was the strongest independent predictor of carotid augmentation index among all of the blood pressure measurements.ConclusionAnkle blood pressure is strongly associated with the augmentation of central blood pressure, and this relation is independent of other blood pressure measures (brachial blood pressure).
Circulating angiogenic factors in a rat model of preeclampsia
Authors: Agunanne Enoch , Uddin Mohammad N , Horvat Darijana , Puschett Jules 
Published: June 2021

ObjectiveWe studied the angiogenic factors in our rat model of preeclampsia (PE) in which marinobufagenin (MBG, a bufodienolide) plays an important role.MethodsAnimals were grouped into: normal, non‐ pregnant (C); normal pregnant (NP); NP injected weekly with DOCA intraperitoneally (IP) and whose drinking water was replaced with 0.9% saline (PDS); NP given daily injections of MBG (0.765 μg/100g) once pregnancy was established; PDS given daily injections of resibufogenin [RBG, an antagonist of MBG (30 μg/kg/day)] IP from day 4 of pregnancy (PDSR). The angiogenic factors were measured on 3–5, 7–10 & 17–20 days of gestation. We have previously shown that MBG levels are already elevated in this model at the 3–5 day time period and remain elevated throughout gestation in PDS rats.Summary of ResultsAt 3–5 days of pregnancy, there was no angiogenic imbalance. At the 7–10 day period, plasma PlGF was greater in the NP than in the PDS. The sFlt‐1/PlGF as well as the placental Flt‐1 and Flt‐1/PlGF were greater in the PDS rats than in NP (p<0.05). These findings were also present at the 17–20 day time point. The levels of these factors in PDSR were similar to those in NP.ConclusionsAngiogenic imbalance contributes to the pathogenesis of the preeclamptic syndrome in our rat model. MBG elevation precedes this alteration in angiogenic factors. This is confirmed by prevention of this imbalance in this study by pretreatment with RBG. Scott, Sherwood/Brindley Foundation.
The hypercoagulability of initial intraosseous aspirates
Authors: Polykratis Irene Amy , Rubal Bernard J. , Sondeen Jill L. , DeLorenzo Robert A. , Dubick Michael A. 
Published: June 2021

Intraosseous (IO) access is a recognized alternative to intravenous routes for administration of resuscitation drugs and fluid therapy. A rapid saline flush immediately following access is reported to improve intraosseous flow rates. We examine the thrombogenicity of initial IO aspirates to elucidate mechanisms for improved flow with flush procedures. In this study thromboelastographic (TEG, Haemoscope Inc., Niles, IL) profiles of initial IO aspirates were compared with whole blood from arterial and central venous catheters in eight swine (40.8 ± 6.5 Kg). The viscoelastic clotting parameters assessed included: R‐time (minutes), K‐time (minutes), angle α (degrees) and maximum amplitude (MA, mm). Intraosseous access was achieved using EZ‐IO 15 GA needle sets (Vidacare, San Antonio, TX). IO aspirates were obtained from the tibia, femur or humerus. In two animals IO aspirates clotted too rapidly for TEG analysis. Table (mean ± 95% CI) compares TEG profiles of IO aspirates with arterial and central venous sites (ANOVA * P<0.05).

R‐time (min)
K‐time (min)
Angle α (degree)
MA (mm)

Arterial
7.9±1.7*
2.0±0.2*
62.4±4.1*
70±2

Venous
5.7±2.3*
1.4±0.5*
71.6±5.4*
72±3

IO
2.3±1.0
0.9±0.1
78.2±0.9
72±8

ConclusionThis study demonstrates hypercoagulability of initial access IO aspirates. Clots form rapidly without flush at the IO cannulation site and contribute to poor IO flow rates.
PROTEOLYTIC CLEAVAGE OF INSULIN RECEPTOR BY PANCREATIC DIGESTIVE ENZYMES LEADS TO INSULIN RESISTANCE IN HEMORRHAGIC SHOCK
Authors: DeLano Frank A , Schmid‐Schönbein Geert W 
Published: June 2021

Hemorrhagic shock is associated with metabolic defects, including hyperglycemia and insulin resistance. The mechanisms are unknown. We recently demonstrated that insulin resistance may involve cleavage of the extracellular domain of the insulin receptor by degrading proteases. In shock, transfer of digestive enzymes into the systemic circulation after breakdown of the intestinal mucosal barrier causes inflammation and organ dysfunction. Suppression of the digestive enzymes in the lumen of the intestine with protease inhibitors was shown in this laboratory to be effective in reducing the level of the inflammatory reactions. To determine what degree blockade of digestive enzymes affects insulin resistance in shock, rats were exposed to acute hemorrhagic shock (mean arterial pressure of 30 mmHg) for 2 hours at which time all shed blood volume was returned. Digestive proteases in the intestine were blocked with a serine protease inhibitor (tranexamic acid, 0.3 mM, in polyethylene glycol‐3350, 60 g/L) and the density of the insulin receptor was measured with immunohistochemistry in the mesentery microcirculation. The untreated rat without enzyme blockade had significantly attenuated levels of insulin receptor density as compared to control and treated rats. Blockade of the digestive proteases after 60 min of hypotension in the lumen of the small intestine lead to a lesser decrease in insulin receptor density compared to controls without protease blockade. These results suggest that in physiologic shock elevated microvascular digestive enzyme activity leads to proteolytic cleavage of the insulin receptor and subsequent insulin resistance(Supported by an academic gift from Leading Ventures and in part by GM85072).
Relationship between markers of bone turnover and coronary arterial calcification in newly menopausal women
Authors: Miyabara Yuko , Kearns Ann E. , Miller Virginia M. 
Published: June 2021

Bone loss and development of atherosclerosis characterized by coronary arterial calcification (CAC) accelerate in women after menopause. This study evaluated the relationship between blood borne markers of bone turnover and development of CAC in newly menopausal women being screened for the Kronos Early Estrogen Prevention Study. Women (n=137) were 52.3±2.3 years of age and were 18.1±9.2 months past their last menses. CAC was measured using 64‐slice computed tomography. Concentrations of osteocalcin, bone alkaline phosphatase (BAP), tartrate‐resident acid phosphatase 5b and osteopontin as bone matrix protein in serum and plasma were evaluated by ELISA. CAC scores ranged from 0 to 327.6 Agatston Unit (AU); 113 women had scores of 0 AU, 20 had CAC scores of 0<50 and 4 had CAC scores >50. Average levels of all of the markers of bone turnover were within a normal range reported in the literature. There was a positive correlation between BAP and osteocalcin. However, levels of these markers did not correlate with age or months past menopause. None of the markers correlated with CAC scores. These results suggest that blood borne markers of bone turnover do not correlate with the presence of CAC in newly menopausal women. Additional work is needed to determine if this relationship would change with increasing age.Supported by the Kronos Longevity Research Institute and Mayo Foundation.
PP2A attenuates cardiac response to LPS‐induced sepsis
Authors: Gergs Ulrich , Schulz Nico , Grossmann Claudia , Gekle Michael , Neumann Joachim 
Published: June 2021

Lipopolysaccharide (LPS), a cell membrane component from Gram‐negative bacteria, is involved in sepsis‐associated cardiac dysfunction. We wanted to know if protein phosphatase 2A (PP2A) influences LPS‐signaling in the heart. Therefore, we used transgenic (TG) mice with heart‐specific overexpression of PP2A. TG and littermate wild type (WT) mice were intraperitoneally injected with 30 μg LPS per g body weight or with NaCl as control (n = 14 – 18 per group). After 3 days, successful induction of LPS‐induced sepsis was monitored by enhanced plasma levels of interleukin‐6. Contractility of WT and TG hearts was analyzed using the isolated work performing heart preparation. Left ventricular systolic pressure (LVP) and the first derivative of developed pressure (+dP/dt and −dP/dt) were decreased in hearts of LPS‐treated WT mice, whereas hearts of TG mice showed no decrease of contractility after LPS‐treatment (Table).

Contractile parameters
Control
LPS

WT
TG
WT
TG

LVP (mmHg)
74±2.2
66±4.3
50±4.3*
61±1.9#

+dP/dt (mmHg/s)
2481±186
2145±254
1306±246*
1901±171#

−dP/dt (mmHg/s)
−1371±114
−1073±139
−720±135*
−1006±115

p<0.05 vs. control,
p<0.05 vs. WT

Quantitative PCR revealed that LPS increased IL‐6 mRNA expression in TG and WT hearts but TNFα mRNA levels only were enhanced in WT. In summary, LPS‐induced myocardial dysfunction was attenuated in TG mice compared to WT. It is tempting to speculate that increased PP2A activity in TG hearts is protective against LPS‐induced sepsis probably via diminished TNFα expression. (Supported by the DFG)
Quantitative synthesis of dynamic baroreflex pressure regulation using baroreflex induced changes in ventricular and vascular properties
Authors: Sakamoto Takafumi , Tsutsumi Takaki , Tanaka Atsushi , Murayama Yoshinori , Tobushi Tomoyuki , Sakamoto Kazuo , Sunagawa Kenji 
Published: June 2021

BackgroundBaroreflex (BR) stabilizes arterial pressure (AP) by changing ventricular and vascular properties. However, how those changes quantitatively determine AP remains unknown. We previously developed a framework of circulatory equilibrium (AJP 2004, 2005) where we can algebraically derive the equilibrium using ventricular end‐systolic elastance (Ees), heart rate (HR), vascular resistance (R) and stressed blood volume (V). Using the framework we investigated if we can quantitatively synthesize AP responses on the basis of BR induced those properties.Methods and ResultsIn 5 anesthetized with isolated carotid sinuses, we randomly perturbed carotid sinus pressure (CSP) using a servo‐pump while recording hemodynamic variables including ventricular pressure‐volume relations. We estimated transfer functions from CSP to HR, Ees, R and V and predicted time domain values of each variable in response to changes in CSP. We then synthesized changes in AP using the equilibrium framework. Synthesized AP matched well with those measured (r2=0.80~0.91). A sensitivity analysis indicated that V and R accounted for 80±6% and 17±6%, respectively, while Ees and HR less than 2% of the BR induced AP changes.ConclusionThe BR induced AP changes can be quantitatively predicted on the basis of BR regulated ventricular and vascular properties. V mainly contributes to the BR induced AP changes.
Cycloxygenase‐2 Inhibition in Endothelium Removed Bovine Pulmonary Arteries Causes Attenuation of Hypoxic Pulmonary Vasoconstriction
Authors: Ahmad Mansoor , Kandhi Sharath , Kelly Melissa R. , Malpani Saurabh , Prieto Dolores , Wolin Michael S. 
Published: June 2021

Superoxide derived peroxide maintains a basal relaxation in endothelium removed Bovine pulmonary arteries (BPA). Removal of this mechanism during hypoxia results in hypoxic pulmonary vasoconstriction (HPV). Inhibition of cyclooxygenase (Cox) 1 and 2 with 10μM Indomethacin resulted in a significant reduction in 5μM lucigenin‐detectable superoxide. Force development to 25mM KCl was not affected in the presence of indomethacin, whereas, HPV was reduced by 63% (n=9). A Cox‐2 inhibitor (1μM NS‐398) decreased superoxide levels and attenuated HPV by 64% (n=8) without affecting 25mM KCl force. However inhibition of Cox‐1 with 1μM SC‐560 did not result in either a decrease in superoxide levels or attenuation of HPV. Thus, inhibition of Cox‐2 and not Cox‐1 in bovine pulmonary vascular smooth muscle results in a decrease in superoxide associated with a partial attenuation of HPV.Supported by NIH grants HL31069, HL43023 and HL66331.
Endothelial Large‐conductance Calcium Activated Potassium (BKCa) Channels And Pulmonary Endothelial Function
Authors: Choudhary Gaurav , Vang Alexander , Newton Julie , Rounds Sharon 
Published: June 2021

We hypothesized that endothelial BKCa channel activation can improve pulmonary endothelial function by causing change in membrane potential (Em), [Ca2+]i and NO release.MethodsLung microvascular endothelial cell (EC) Em, [Ca2+]i and NO change was measured using fluorescence imaging with DiBAC4(3), Fura‐2AM and DAF‐FM, respectively. Phenylephrine preconstricted pulmonary arterial (PA) rings were used to assay the effect of acetylcholine (Ach) on vessel relaxation. PA pressures were monitored in preconstriced isolated ventilated‐perfused rat lungs (IPL) after BKCa channels activation.ResultsBKCa channels were demonstrated in macro‐ and microvascular endothelium by immunohistochemistry in rat lungs and by immunoblot in EC lysates. BKCa channel activation with 30μM NS1619 led to endothelial hyperpolarization and an increase in [Ca2+]i and NO. Also, NS1619 caused enhanced endothelium‐dependent dilation in PA rings, with no effect on endothelium‐independent dilation using NO donor or endothelium‐denuded rings. K+ channel blocker, TEA, abolished the effect of NS1619 on endothelium dependent dilation. In IPL, BKCa channel activation by NS1619 caused a dose‐dependent reduction in PA pressures that was attenuated by the inhibition of NO production.ConclusionPulmonary EC express BKCa channels. Activation of pulmonary endothelial BKCa channels leads to improvement in endothelial function.
Sphingomyelinase and ceramide increase reactive species and depress maximal skeletal muscle force in vitro
Authors: Ferreira Leonardo F , Smith Jeffrey D , Moylan Jennifer S , Reid Michael B 
Published: June 2021

Activation of Sphingomyelinase (SMase) depresses maximal muscle force: an effect blunted by antioxidants. In non‐muscle cells, SMase catalyzes the breakdown of sphingomyelin into ceramide, which increases reactive oxygen and nitrogen species (i.e., oxidants). Thus, we tested three hypotheses: i) SMase increases ceramide levels in myocytes; ii) SMase and ceramide increase oxidants in myocytes; and iii) ceramide depresses skeletal muscle force. We performed experiments in differentiated mytubes and murine diaphragm. Myotubes were exposed to SMase (0.5 U/ml), C2‐ceramide (10 μM), C6‐ceramide (10 μM), or vehicle (CTRL) for 20 min at 37°C. Diaphragm fiber bundles were exposed to C6‐ceramide in vitro (20 μM, 30 min, 37°C). Our results show that SMase increased total ceramide levels (in pmol/nmol Pi: CTRL 1.96 ± 0.09, SMase 5.47 ± 0.36; p < 0.05). Oxidant‐stimulated fluorescence was increased by C2‐ceramide (17 ± 6%; p < 0.02), C6‐ceramide (25 ± 5%; p < 0.001), and SMase (35 ± 8%; p < 0.001). Reactive nitrogen species‐dependent fluorescence was unaffected by SMase (CTRL 179.4 ± 3.6 a.u., SMase 179.5 ± 3.8 a.u.). C6‐ceramide decreased maximal diaphragm force by 56 ± 10% (p < 0.05). We conclude that SMase increases reactive oxygen species in muscle cells. This effect appears to be mediated by ceramide and results in depression of maximal skeletal muscle force.*Funding provided by NIH (R01 AR055974) and AHA‐GRA (09POST2020082)
Myofilament structure in muscle from tissue specific Bmal1 KO mice
Authors: Houtz Jessica , Campbell Kenneth , Esser Karyn 
Published: June 2021

We have observed that skeletal muscle from the arrhythmic germline Bmal1 knock out mouse (Bmal1 KO) exhibits significant weakness defined by a reduction in muscle specific tension. Evaluation of electron micrographs (EMs) from cross‐sections of adult gastrocnemius muscles reveals obvious divergences from the normal hexagonal arrangement of thin and thick filaments in the Bmal1 KO mice.The objective of this project is to address whether the structural pathology in muscle is the result of local or systemic loss of Bmal1. We have generated a striated muscle specific Bmal1 KO mouse and developed a computational tool for the quantitative analysis of myofilament architecture. Bmal1 is selectively eliminated in striated muscle by crossing the MCK‐Cre mouse with the floxed Bmal1 mouse. Muscle structure will be evaluated with newly developed image processing software that identifies bundles of actin (thin filaments) or myosin (thick filaments) in EMs of muscle cross‐sections. Preliminary programming detects myofilaments as intensity peaks in the gray‐scale image and categorizes them as thick or thin depending on the cross‐sectional area of the peaks. Cellular–level muscle function is assessed using permabilized single fiber mechanics. The results of this work will determine whether local muscle specific expression of Bmal1 is necessary for maintenance of adult skeletal muscle structure and function.