bluuebunny/crossref_metadata_2025 huggingface dataset:
Lipin/phosphatidic acid phosphatase in lipid metabolism and cell physiology
Authors: Carman George M
Published: June 2021

Phosphatidate (PA) phosphatase catalyzes the dephosphorylation of PA to produce diacylglycerol (DAG) and Pi. The DAG produced in the reaction is used for the synthesis of triacylglycerol (TAG) and for the synthesis of phosphatidylethanolamine and phosphatidylcholine via the Kennedy pathway. The discovery that PAH1 encodes PA phosphatase in yeast led to the revelation that the mouse fat‐regulating protein named lipin is a PA phosphatase enzyme. The location and catalytic efficiency of the yeast enzyme are governed by multiple phosphorylations/dephosphorylations, whereas enzyme expression is governed by transcriptional and posttranscriptional mechanisms. Yeast pah1 mutants have increased levels of PA and palmitoleic acid in membrane phospholipids, and reduced levels of DAG and TAG. The TAG deficiency renders pah1 mutants exceptionally sensitive to fatty acid (e.g., palmitoleic acid)‐induced toxicity. The elevated PA content in pah1 mutants causes the induction of phospholipid synthesis gene expression and the aberrant expansion of the nuclear/ER membrane. The pah1 mutant also exhibits a respiratory deficiency phenotype, a decreased life span, and sensitivity to growth at elevated temperature. This work is supported by National Institutes of Health grants GM‐28140 and GM‐50679.
Co‐regulation of Transcellular and Paracellular Leak Across Microvascular Endothelium By Dynamin and Rac
Authors: Lee Warren Lester , Armstrong Susan , Khajoee Vahid , Wang Changsen , Wang Tieling , Tigdi Jayesh , Yin Jun , Kuebler Wolfgang M. , Gillrie Mark , Davis Shevaun , Ho May
Published: June 2021

Increased permeability of the endothelium is the hallmark of inflammation. Leakage can occur between (paracellular) or through (transcytosis) endothelial cells, yet little is known about whether these pathways are linked. We investigated whether transcytosis and paracellular leakage are co‐regulated. Using molecular and pharmacologic approaches, we inhibited transcytosis of albumin in primary human microvascular endothelium and measured paracellular permeability. Blockade of transcytosis induced an increase in paracellular leak that was not explained by decreases in caveolin‐1 or by increased activity of nitric oxide synthase. The effect required caveolin‐1 but occurred in cells depleted of clathrin, indicating that it was not due to the general inhibition of endocytosis. Inhibiting transcytosis by blocking dynamin increased paracellular leak concomitantly with the loss of cortical actin from the plasma membrane and the displacement of active Rac from the plasmalemma. Importantly, inhibition of paracellular leak by sphingosine‐1‐phosphate, which activates Rac and induces cortical actin, caused a significant increase in transcytosis of albumin in vitro and in an ex vivo whole lung model. Dominant‐negative Rac diminished albumin uptake by endothelia. Thus, transcytosis and paracellular permeability are co‐regulated through a signalling pathway linking dynamin, Rac and actin.
Hsp90 inhibition prevents bacterial lipopolysaccharide‐induced and RhoA‐mediated signaling leading to paracellular hyper‐permeability in human lung microvascular endothelial cells
Authors: Joshi Atul D , Aggarwal Saurabh , Thangjam Gagan , Snead Connie , Feldman Sara , Black Stephen M , Catravas John D
Published: June 2021

We have previously shown that hsp90 inhibitors protect and restore bacterial lipopolysaccharide (LPS) ‐ mediated barrier dysfunction of human lung microvascular endothelial cells (HLMVEC). Since RhoA is a well‐known mediator of endothelial barrier dysfunction, we investigated the role of hsp90 in LPS‐induced and RhoA mediated HLMVEC hyper‐permeability. LPS (1 EU/ml) challenge of HLMVEC significantly increased RhoA tyrosine nitration and RhoA activity. Pre‐treatment (1 hr) with the hsp90 inhibitor, 17‐AAG (2 uM) suppressed both RhoA nitration and RhoA activity. Pre‐treatment with GSK429286 (10 uM), an inhibitor of the RhoA effector, Rho kinase (ROCK) partially rescued the LPS‐mediated HLMVEC hyper‐permeability, as reflected in changes in transendothelial electrical resistance (TER) of HLMVEC monolayers. Furthermore, GSK429286 pretreatment abolished the LPS‐induced phosphorylation of both CREB (Ser133) and STAT3 (Tyr705), two pro‐inflammatory transcription factors regulated by hsp90. These data suggest that the barrier protective effects of Hsp90 inhibition in HLMVEC involve suppression of RhoA‐ROCK signaling and inhibition of CREB and STAT3. (Supported by HL093460 and HL101902)
A Method for Measuring 3D Cardiac Surface Mechanics with High‐Speed Structured Light Imaging
Authors: Laughner Jacob Israel , Li Hao , Zhang Song , Efimov Igor R
Published: June 2021

Cardiac disease often manifests as a combination of electrical and mechanical remodeling. The relationship between whole‐heart epicardial mechanics and electrophysiology is crucial to our understanding of cardiac arrhythmias in the settings of heart failure. While advances in imaging technology have allowed for accurate descriptions of surface deformation in 2D and 3D, current imaging technologies are often hampered by poor temporal resolution that limits imaging to repeated patterns. Moreover, structural correspondences are often achieved with fiducial markers attached to finite locations—limiting the resolution for mechanical analysis. Here, we demonstrate the potential of a high‐speed structured light imaging system to capture and describe whole‐heart 3D epicardial motion. Additionally, we developed a novel motion‐tracking algorithm to form correspondences between 3D frames. All imaging was performed on isolated rabbits hearts (n = 4), Langendorff‐perfused with oxygenated Tyrode's solution at a constant pressure of 60 mmHg. By combining our structured light imaging system with surface registration, we are able to image and describe cardiac motion at more than 200,000 locations and kHz frames rates during normal sinus rhythm, ventricular pacing, and ventricular fibrillation. Our new method will allow combined electro‐mechanical imaging of intact hearts. Supported by NIH Grant RO1 HL067322.
Anatomical effect of lateral decubitus position on circulation and heart rate variability in healthy adults
Authors: Sasaki Konosuke , Haga Mayu , Matsui Noriko , Nagai Mizuki , Maruyama Ryoko
Published: June 2021

We compared the impact of the right and left lateral decubitus positions and the supine position on heart rate variability (HRV), including circulatory regulation. In 39 healthy volunteers aged 23.6 ± 3.3 years, we performed electrocardiographic measurements. Further, we conducted echocardiographic assessment of the inferior vena cava (IVC) in each posture. A male patient with situs inversus totalis (63 years) also participated in this study. Subjects randomly maintained each lateral position at an angle of over 45° for 10 min after remaining in the supine position. Of the subjects, 20 were initially turned to the left lateral position from the supine position, whereas the others were initially turned to the right lateral position. No significant differences were observed in high‐frequency or low frequency HRV or their ratio. However, the heart rate (HR) was significantly lower in the left lateral position than in the supine position and blood in the IVC tended to flow more rapidly in the left lateral position than in the supine position. Interestingly, the temporal changes in HR varied according to the order of postural change. Unlike the subjects, the patient showed a decrease in HR in the right lateral position. These findings suggest that the order of postural change has an influence on circulatory dynamics. In particular, the reduction in HR in the left lateral position may be affected by anatomical changes.
Surgical excision of coronary epicardial adipose tissue provides evidence for its role in coronary artery disease
Authors: Schultz Kyle , Boyd Jack , Byrd James Patrick , McKenney Mikaela , Chawla Aarti , Alloosh Mouhamad , Teague Shawn , Sacks Harold , Sturek Michael
Published: June 2021

Coronary artery disease (CAD) is the accumulation of atherosclerotic plaque within the lumen of large epicardial conduit arteries. Past research has shown strong positive association between coronary epicardial adipose tissue (cEAT) and CAD. We tested a contributory role for cEAT in CAD by surgical excision of cEAT and longitudinal measures of CAD with intravascular ultrasound (IVUS). Ossabaw swine (N=8) were fed an atherogenic diet for 6 months to produce metabolic syndrome and CAD. IVUS was performed prior to an adipectomy of the cEAT on the proximal half of the left anterior descending (LAD) coronary artery, while the circumflex (CFX) was left as a sham control. Recovery of 3 months was allowed on the same diet, followed by IVUS measures of the LAD and CFX to determine atheroma changes. As predicted, there was an increase in CAD during recovery (p<0.05). The increase in the proximal LAD was only 10% of that in the CFX. Likewise an increase in the proximal and middle LAD combined was 38% of the same CFX region (p<0.05). Computed tomography (CT) showed increases in pericardial fat and association with CAD during recovery, but cEAT at the adipectomy site could not be quantified with CT. We conclude these data suggest cEAT removal decreased the progression of coronary atherosclerosis. (Support: NIH HL062552, Cardiometabolic Disease Research Foundation, Memphis, TN)
Perivascular adipose tissue in age‐associated arterial stiffening: Role of transforming growth factor beta 1
Authors: Fleenor Bradley S , Snieder Hylke , Marshall Kurt D , Seals Douglas R
Published: June 2021

Aging causes large elastic artery stiffening associated with adventitial myofibroblast‐related increases in transforming growth factor beta 1 (TGF‐β1), collagen I and advanced glycation end‐products (AGEs). We tested the hypothesis that perivascular adipose tissue (PVAT) from older animals induces these protein changes in adventitial fibroblasts (AFB) and that the increase in TGF‐β1 causes arterial stiffening. AFB cultured from old (O, 24 mo, n=3–6) vs. young (Y, 6 mo, n=4–6) male Sprague Dawley rats had greater (p<0.05) smooth muscle alpha actin (SMαA, 1.92 ± 0.21 vs. 1.00 ± 0.08), a marker of myofibroblasts, TGF‐β1 (15.77 ± 1.13 vs. 1.00 ± 0.21), collagen I (1.71 ±0.04 vs. 1.00 ± 0.14) and AGEs (4.49 ± 1.69 vs. 1.00 ± 0.20). In AFB from Y, PVAT from O rats increased (p < 0.05) SMαA (1.76 ± 0.18), TGF‐β1 (7.28 ± 1.98) and collagen I (1.58 ± 0.21), but not AGEs (1.12 ± 0.38), and TGF‐β1 treatment mimicked these changes (SMαA: 1.00 ± 0.14 to 3.00 ± 0.44 and collagen I: 1.00 ± 0.04 to 1.71 ± 0.14, both p < 0.05; AGEs: 1.00 ± 0.04 vs. 0.91 ± 0.22). Arterial stiffness (aortic pulse wave velocity, aPWV) was greater (p < 0.05) in O (26–27 mo, n=5) vs. Y (4–6 mo, n=5) male C57Bl/6N mice (469 ± 16 vs. 351 ± 13) and 6‐week direct arterial application of recombinant TGF‐β1 to the aorta in vivo increased (p<0.05) aPWV in Y (417 ± 6). These results suggest that PVAT may contribute to age‐associated arterial stiffening via TGF‐β1.

NIH AG013038, HL007822
MYPT1 isoform expression is regulated by p42/44 signaling
Authors: Brozovich Nikolas J , Hawes Grescin , Yuen Samantha , Ogut Ozgur , Brozovich Frank V
Published: June 2021

During NO mediated vasodilatation, PKG activates myosin light chain (MLC) phosphatase to reduce MLC phosphorylation and force. MLC phosphatase is a trimeric enzyme consisting of a catalytic, myosin targeting (MYPT1) and 20 kDa subunits. Alternative mRNA splicing produces four MYPT1 isoforms, which differ by the presence or absence of central insert (CI) and a carboxy‐terminal luecine zipper (LZ). PKG mediated activation of MLC phosphatase requires the expression of a LZ+ MYPT1 isoform, and during heart failure, there is an activation of p42/44 MAPK signaling and a decrease in LZ+ MYPT1 expression. We examined p42/44 MAPK signaling and LZ+ MYPT1 expression during angiotensin II (AngII) stimulation of cultured smooth muscle cells (SMCs). AngII resulted in a time dependent activation of p42/44 MAPK and a decrease in LZ+ MYPT1 expression. However pretreatment of the SMCs with a MEK inhibitor (PD98059) blocked the AngII induced activation of p42/44 MAPK and decrease of LZ+ MYPT1 expression. These results demonstrate that LZ+ MYPT1 expression is regulated by a p42/44 MAPK signaling pathway. During heart failure, treatment with either ACE inhibitors or AngII receptor blockers will prevent the activation of p42/44 MAPK and the resulting decrease in LZ+ MYPT1 expression to preserve the sensitivity of vascular smooth muscle to NO mediated vasodilatation.
Flow‐regulation of Vascular Smooth Muscle Cell Proliferation: Roles of Endothelial Cell‐secreted MicroRNA‐126
Authors: Zhou Jing , Li Julie Y.-S , Chien Shu
Published: June 2021

MicroRNAs (miRs) are noncoding RNAs that regulate mRNA stability and translational repression. In addition to their primary intracellular locations, miRs have also been detected extracellularly in plasma and other body fluids. MiRs produced by cells can be secreted as signaling molecules to be taken up by receiving cells to result in gene silencing. We investigated the roles of miR‐126, which is an endothelial cell (EC)‐enriched key regulator for vascular integrity and angiogenesis, in regulating flow‐mediated smooth muscle cell (SMC) proliferation. The results indicate that ECs released miR‐126 into the extracellular environment to cause an increase of miR‐126 in the SMCs, and that laminar flow shear stress applied to ECs attenuated such effects. MiR‐126 is delivered as both the vesicle‐free Argonaute 2 (Ago2)/miRs complex and as the membrane‐bounded microvesicles/exosomes. After being taken up, miR‐126 in SMCs directly represses FOXO3, BCL2 and IRS1 expression and leads to the increase of SMC proliferation. Our investigation has identified potential molecular targets and their functional mechanisms responsible for the initiation and progression of vascular proliferative disorders as a result of EC/SMC interactions under static and shearing conditions. This study highlights the function of miRs as mediators for the flow shear stress‐regulated cell‐cell communications in the vascular system.
K2P6.1 Knockout Mice Have Varied Endothelial‐Mediated Relaxation With Elevated Endothelial‐Mediated Contraction
Authors: Lloyd Eric E , Crossland Randy F , Pandit Lavannya M , Marrelli Sean P , Bryan Robert M
Published: June 2021

K2P6.1, a Two‐Pore Domain K channel expressed in vascular smooth muscle, is necessary to maintain normal peripheral vascular resistance and mean arterial pressure in C57/SV129 mice. However the functional state of the endothelium in these mice has not previously been assessed. We tested the hypothesis: K2P6.1‐ deficient mice (8–12 wks) have impaired endothelial‐mediated relaxation due to elevation in endothelial‐derived contracting factors. 24‐hour mean telemetry of conscious mice showed elevated blood pressures (MAP 96±11 vs. 143±14 & SBP 109±12 vs. 158±11 mmHg in WT and KO mice respectively, n=6, p<0.05). Endothelial‐mediated vasorelaxation of thoracic aorta was evaluated by isometric myography. Aorta were precontracted with phenylephrine (10‐5M) and subsequently relaxed with carbachol (CCH) and acetylcholine (CCH). Relaxations were enhanced in KO aorta by 56±5% (n=9, p<0.001) and 33±5% (n=6, p<0.01) for CCH and ACH, respectively. In contrast, relaxations to ATP and ADP were impaired by 39±5% (n=8, p=0.01) and 38±6% (n=8, p<0.05) in KO aorta, but were normalized with 10‐5M indomethacin (n=8). Indomethacin‐sensitive contractions using non‐precontracted aorta with 10‐4M LNAME were elevated in KO mice to ACH by 66±2% (n=4, p=0.04) and to ATP by 41±4% (n=7, p=0.05). In summary, knockout of K2P6.1 either augments or inhibits vasorelaxation depending on the agonist system. Funded by NIH 5R21HL098921‐02
Effects of slow breathing exercises on reduction of arterial blood pressure and changes in NOergic biomarkers over meridians
Authors: Ma Sheng-Xing , Jiang Isabelle , Smith Brian , Hu Jay
Published: June 2021

These studies observe the effects of slow breathing exercises (SBE) on arterial blood pressure (ABP) and nitric oxide (NO)‐ cGMP/nitrotyrosine concentrations over meridians in healthy volunteers and essential hypertension patients. Device (RespeRate)‐guided SBE was performed for 30 min in healthy volunteers. Hypertensive patients practiced SBE for 30 min daily over 7 days. A biocapture device was taped to the skin over the Pericardium and Bladder Meridian before and after SBE. The concentrations of total nitrate and nitrite, cGMP and nitrotyrosine, a stable end‐product of oxidative stress mainly from peroxynitrite, in the samples were quantified using chemiluminescence and ELISA. ABP, heart rate, and breathing rate were measured in the morning and afternoon each day from study diaries. Results show that cGMP levels are decreased and levels of nitrotyrosine over acupoints are as much as 6 fold higher in hypertensive patients. SBE increased cGMP levels over acupoints in both normatensive and hypertensive subjects. Nitrotyrosine concentrations are significantly reduced following a seven day SBE in hypertensive patients. Averaged ABP during 7 days's measurements following SBE were significantly decreased in hypertensive patients. Results suggest that restored NO‐cGMP bioavailability resulting in reduction of nitrotyrosine level is associated with a reduction of ABP induced by SBE.
Effects of Testosterone on Vascular Reactivity in Male Sprague – Dawley Rats Fed a High Salt Diet
Authors: Oloyo Ahmed Kolade , Momoh Yakubu , Sofola Olusoga , Oyekan Adebayo
Published: June 2021

Sex hormone‐dependents vascular reactivity is an underlying factor contributing to gender differences in salt‐dependent hypertension. This study evaluated the role of androgens on vascular reactivity in the perfused hind limb preparation in salt ‐ induced hypertension. Weanling male rats (8 weeks old; weight, 180 – 200)g were bilaterally orchidectomised or sham‐operated with or without testosterone replacement (10mg/kg sustanon 250® i.m once in 3 weeks), and were placed on normal (0.3%) or high (4%) NaCl diet for 6 weeks. Rats fed a high salt diet (HSD) showed increases in arterial blood pressure (BP) [11.92%], renal vascular resistance (RVR) [17.24%], fluid balance (FB) [92%], that was accompanied by decreased plasma nitric oxide (NO) production [65.62%]. Orchidectomy reversed but testosterone replacement restored the increased (P < 0.05) BP, RVR, and FB observed in the rats fed a HSD. HSD increased response to PE [30.31%] but this was reversed and restored by orchidectomy and testosterone replacement respectively. HSD also impaired vasorelaxation to ACh [29.11%] and SNP [44.22%]. Orchidectomy attenuated the impaired relaxation response to ACh and SNP observed in the HSD fed rats. Testosterone promotes the impairment of vascular function observed in HSD and this may involve the NO pathway.
Peripheral macrophage depletion impairs phenylephrine mediated contraction in aorta from stroke prone spontaneously hypertensive rats, but does not alter the effect of perivascular fat
Authors: Dorrance Anne McLaren , Pires Paulo Wagner , McClain Jonathon Lee , Watts Stephanie W
Published: June 2021

Perivascular fat limits contraction in isolated aortic rings. These studies have been largely conducted in normotensive rats. We proposed that perivascular fat would impair contraction in aorta from stroke prone spontaneously hypertensive rats (SHSRP) and that peripheral macrophage depletion would exacerbate this impairment. SHRSP were treated with liposome‐encapsulated clodronate (CLOD) or placebo for six weeks from six weeks of age to remove the peripheral macrophages. Aortae where then removed and mounted in a wire myograph to measure isometric force generation with and without perivascular fat. CLOD had no effect on blood pressure (201±7 vs 200±5 mmHg, control vs CLOD) or body weight (251±7 vs 248±3g, control vs CLOD). The phenylephrine (PE) induced contraction was impaired in the aorta + fat from control SHRSP. Interestingly, macrophage ablation reduced the PE mediated contraction in the clean aorta but not in the aorta + fat. The KCl induced contraction was also reduced in the presence of fat in both groups. These results suggest that macrophage deletion has direct effects on the vascular smooth muscle to reduce contraction.

Control (n=5)
Control+Fat
CLOD (n=6)
CLOD+Fat

Max PE contraction (% of KCl)
85.3±5.2
65.9±4.8*
71.3±2.4*
59.2±3.1

EC50
−7.7±0.2
−6.7±0.1*
−7.3±0.2
−6.7±0.2

KCl induced contraction (mN)
23.5±1.6
14.4±0.2*
30.0±1.8
16.1±1.7#

different from Control.

different from CLOD
Relationship between Dyslipidemia and Hypertension in ZDSD, a New Rodent Model of Metabolic Syndrome
Authors: Rice Ami E , Tlem Hlawn kip , Tial Sui tin , Johnson Jamie L , Schurtz Stacy L , Coy Kathy , Peterson Richard G , Packer C Subah
Published: June 2021

Metabolic syndrome (MetS), an epidemic disorder characterized by obesity, dyslipidemia, high blood pressure (HBP) and hyperglycemia, is the leading cause of cardiovascular disease. The general thinking has been that the HBP is associated with the diabetes. However, a pilot study of the development of HBP in a new leptin‐intact rat model, ZDSD, suggested that HBP develops prior to diabetes. The current serial time course study addressed the Hypothesis: HBP is a direct consequence of the hypercholesterolemia/hypertriglyceridemia developed early in MetS prior to diabetes and is subsequently exacerbated by high blood glucose. ZDSD and niacin‐treated ZDSD systemic BP, body weights, circulating lipids and glucose were monitored as functions of age and compared with control CD and SD values. Results support the earlier work in that hypercholesterolemia and hypertriglyceridemia both preceded HBP in ZDSD and HBP was not dependent on diabetes or obesity. Surprisingly, niacin did not protect against dyslipidemia or HBP in ZDSD. Other interventions will need to be studied in order to elucidate cause and affect relationships and mechanisms between circulating biomarkers and cardiovascular disease in MetS.
Intracellular acidification inhibits NO synthesis and rho‐kinase‐mediated signaling in arteries
Authors: Boedtkjer Ebbe , Praetorius Jeppe , Matchkov Vladimir , Stankevicius Edgaras , Damkier Helle , Mogensen Susie , Simonsen Ulf , Füchtbauer Ernst-Martin , Aalkjaer Christian
Published: June 2021

We studied the background for pHi‐mediated effects on artery function and blood pressure regulation in knockout mice for Na+,HCO3−‐cotransporter NBCn1 and Na+/H+‐exchanger NHE1. When compared to arteries from wild type, intracellular acidification in arteries from both knockout mouse strains inhibited acetylcholine‐induced NO‐mediated vasodilation while vasodilation to NO‐donors was unaffected. NO concentrations and NO‐synthase activity were reduced in arteries from NBCn1 knockout mice while NO‐synthase expression (total and Ser‐1177 phosphorylated) and endothelial Ca2+ i‐responses to acetylcholine were unchanged. Intracellular acidification also reduced rho‐kinase‐dependent smooth muscle Ca2+‐sensitivity and phosphorylation of myosin phosphatase targeting subunit at Thr‐850. NBCn1 knockout mice were mildly hypertensive at rest and displayed reduced blood pressure responses to L‐NAME treatment, rho‐kinase inhibition or angiotensin II infusion. In conclusion, intracellular acidification inhibits NO synthesis and rho‐kinase‐dependent smooth muscle Ca2+‐sensitivity in arteries and perturbs blood pressure regulation. Financial support: Danish Council for Independent Research and Danish Heart Foundation.
Identifying Plekha7, an adherens junction protein, as a regulator of protein excretion in the kidney
Authors: Endres Bradley , Moreno Carol , Lombard Julian , Jacob Howard , Geurts Aron
Published: June 2021

Zinc‐finger nucleases (ZFNs) have enabled us to study the roles of genes involved in complex diseases such as hypertension and renal failure. One gene, Plekstrin homology domain containing family A member 7 (Plekha7), has been linked in multiple genome‐wide association studies to elevated systolic blood pressure. We have knocked out Plekha7 using ZFNs in the Dahl salt‐sensitive (SS) rat to study its role in the regulation of blood pressure in response to a high salt (8% NaCl) diet. While results show that blood pressure was not different between Plekha7 −/− rats and control rats, urinary protein excretion was significantly reduced by 30% in the Plekha7 −/− rats in comparison to control rats on a high salt diet. Histological analysis of the kidneys indicates that protein casting was significantly reduced in the Plekha7 −/− rats. Interestingly, Plekha7 −/− rats’ aortas also had a significantly reduced maximum relaxation to acetylcholine, 45.8±5.4%, compared to control rats, 59.9±2.9%. PLEKHA7 is an adaptor protein involved in linking adherens junctions to the microtubule cytoskeleton. Assessment of downstream targets of PLEKHA7 indicates that modifying this protein up‐regulates RhoA, an activator of proliferation. In conclusion, preliminary phenotyping of the Plekha7 knockout rats demonstrates that Plekha7 plays a role in the homeostasis of the kidney and vasculature, independent of salt‐induced hypertension.
Abnormal conduit artery shear rate patterns during mental stress in patients with cardiometabolic risk
Authors: Sales Allan R K , Rocha Natalia G , Campos Luiz P , Bertoldi Julia J , Alves Renata , Garcia Vinicius P , Vianna Lauro C , Silva Bruno , Nobrega Antonio CL
Published: June 2021

Disturbed flow patterns, characterized by the presence of retrograde and oscillatory shear stress, are associated with proatherogenic phenotype. Mental stress consistently induces forearm vasodilation, and evidence suggests that increased cardiometabolic risk (CMR) blunts this response. Importantly, whether this altered vascular response of CMR patients during mental stress impacts the conduit artery shear rate patterns remains unknown. To begin to examine this, 7 CMR patients (36±3 years) and 4 healthy subjects (controls; 34±5 years) underwent a 3‐min mental stress test (Stroop color‐word test), while beat‐to‐beat blood pressure (finger photoplethysmography), brachial blood flow (BF; Doppler ultrasound) and forearm vascular conductance (FVC; BF/mean BP) were continuously monitored. Mental stress significantly increased BP and FVC in controls (P<0.05). In CMR patients, however, while BP was similarly augmented during mental stress, increases in FVC were abolished (−26±12%; P>0.05). Flow patterns were similar between groups at rest but clear differences in retrograde shear (−15.1±4 CMR vs. −3.49±1 s‐1 controls; P<0.05) and oscillatory shear index (0.27±0.04 CMR vs. 0.11±0.06 a.u., controls; P<0.05) were noted during mental stress. These preliminary findings suggest that the blunted vascular responses of CMR patients during mental stress test are associated with disturbed flow patterns.
Effect of Omega‐3 PUFA on Endothelin‐1 Receptors in Normal and Type 1 Diabetic Rat Hearts
Authors: Bikhazi Anwar B , El Chami Mohamad Imad , Zwainy Nadine S , Der-Boghossian Asdghig H
Published: June 2021

Cardiovascular disease is a major complication in diabetes. Its management includes renin‐angiotensin‐system components, endothelial factors (Nitric Oxide), or Endothelin‐1 (ET‐1) regulation. This study focuses on long‐term ET‐1 receptor regulation by ω‐3 and Statin at coronary endothelium (CE) and cardiomyocytes (CM) levels in diabetic rats. Sprague Dawley male rats (n=24) were assigned to 7 groups: normal (N); streptozotocin (STZ)‐induced diabetic (D); normal rats treated with ω‐3 (0.085g/kg) (NO) or Statin (0.89 mg/kg) (NS); diabetic rats treated with ω‐3(DO), Statin (DS) or both (DOS). After a month of treatment, their hearts were perfused with [125I]‐ET‐1 (CHAPS‐untreated for CE and CHAPS‐treated for CM analyses) to estimate ET‐1 receptor‐binding affinity (τ = 1/K−n) on CE and CM. Tissue samples were analyzed by western blot for ET‐1 receptor subtypes A (ETAR) and B (ETBR). Residency time constant, τ, of ETBR increased in all groups as compared to N (1.05 ± 0.06), except for DS (1.18 ± 0.07) which was normalized. As for ETAR, τ increased in all groups but normalized in DO (1.18 ± 0.07). In western blot, ETAR increased (1.31 ± 0.09 vs 0.96 ± 0.05) and ETBR decreased (1.00 ± 0.06 vs 1.30 ± 0.07) in D, but both values were corrected in all other groups. Thus, ω‐3 and Statin therapy improved ETAR and ETBR functions respectively in diabetics; however, ω‐3 dosage regimens needs further analysis in healthy subjects.
Dysfunctional bone marrow‐derived endothelial progenitor cells in chronic Ang II infusion rat model of hypertension
Authors: Jun Joo Yun , Zubcevic Jasenka , Afzal Aqeela , Carvajal Jessica Marulanda , Shan Zhiying , Mocco J , Raizada Mohan K
Published: June 2021

Bone marrow (BM)‐derived endothelial progenitor cell (EPC) contribute to the maintenance of vascular homeostasis and EPC dysfunction is implicated in the vascular pathophysiology in hypertension. Thus, we propose Angiotensin II (Ang II)‐induced neurogenic hypertension is associated with dysfunctional EPC and elevated inflammatory cells (ICs). Ang II infused SD rats (200ng/kg/min, SC, 4–12 weeks) were used to induce hypertension. CD90+/CD4−/5−/8cells were isolated from femur and blood and their functions were assessed. BM and blood EPC decreased by 35% and 70% after 4 and 12 weeks of Ang II infusion, respectively. This was associated with significant increases in BM and blood IC (CD4+/8+/25+, CD3+/45+; CD68+) measured by FACS, leading to significant reduction in EPC/IC. BM EPC migration and proliferation ability toward SDF was reduced by 70±5% at 6 wks, 75±4% at 12 wks, and by 40±3% at 6 wks, 44±5% at 12 wks of Ang II infusion, respectively. Tube formation assay showed endothelial cells from Ang II rats decreased tube length (~25%) and branch numbers (~23%) compared to control. RT‐PCR also showed significant decrease in CXCR4 (~30%) and CXCL12 (~40%) mRNA from 12 weeks Ang II rats. In summary, these data demonstrate EPC/IC is significantly decreased as a result of decreased EPC/increased IC in Ang II induced hypertension. EPC from hypertensive rats are dysfunctional with decreased SDF‐1 and its receptor mRNA.

HL33610
Regulation of the Na, HCO3‐cotransporter NBCn1 (SLC4A7) by a constitutively active ErbB2 receptor in MCF‐7 breast cancer cells
Authors: Gorbatenko Andrej , Olesen Christina W , Lauritzen Gitte , Valen Evind , Pedersen Stine Falsig
Published: June 2021

We recently showed that the Na+, HCO3− cotransporter NBCn1 (SLC4A7) is strongly upregulated at the mRNA and protein levels in MCF‐7 breast cancer cells upon expression of a truncated constitutively active ErbB2 receptor (ΔNErbB2) common in breast cancer. Here, we explore the mechanisms involved in this upregulation. NBCn1 expression was also increased by stimulation of full‐length ErbB receptors. NBCn1 mRNA and protein levels in ΔNErbB2‐, but not in vector‐expressing MCF‐7 cells were reduced by inhibition of ERK or Src. PI3K‐Akt inhibition reduced NBCn1 expression in both cell types, suggesting a general rather than a ΔNErbB2‐specific role of this pathway. The putative promoter region was identified bioinformatically, and reporter assays using a 1.2 kb genomic region upstream of the slc4a7 gene showed that ΔNErbB2 expression increased luciferase activity 2.5 fold, demonstrating regulation of the NBCn1 promoter by ErbB2 signaling. The possible involvement of STAT3‐ and SP1‐dependent pathways is under investigation.

In conclusion, downstream from ΔNErbB2, NBCn1 expression is strongly increased, at least in part through ERK‐ and Src‐dependent pathways impacting on the NBCn1 promoter region. Funding: Novo Foundation.
Modulation of cardiac Na+, K+‐ATPase and cell viability by Ischemia/Reperfusion Injury and Ouabain Preconditioning
Authors: Pierre Sandrine V , Belliard Aude , Sottejeau Yoann , Duan Qiming
Published: June 2021

Na+, K+‐ATPase and cell survival were investigated in a cellular model of ischemia‐reperfusion (IR)‐induced injury and protection by ouabain‐induced preconditioning (OPC). Rat neonatal cardiac myocytes were subjected to 30 minutes of substrate and coverslip‐induced ischemia followed by 30 min of reperfusion. This significantly compromised cell viability as documented by LDH release and Annexin V/PI staining. Total Na+, K+‐ATPase α1‐ polypeptide expression remained unchanged, but cell surface biotinylation and immunostaining studies showed a significant decrease in cell surface abundance. Na+, K+‐ATPase‐activity and 86Rb+ transport in live cells were decreased by about 30%. OPC increased cell viability by about 40% in a PKCε‐dependent manner and prevented IR‐induced modulation of Na+, K+‐ATPase activity and surface expression. However, it did not prevent IR‐induced decrease of 86Rb+ transport, suggesting that the protection against cell death was not conferred by increased Na+, K+‐ATPase‐mediated ion transport capacity at the cell membrane. Consistent with this observation, transient expression of a mutant form of Na+, K+‐ATPase α1 with increased surface abundance without increased ion transport activity successfully reduced IR‐induced cell death. These results suggest that maintenance of Na+, K+‐ ATPase cell surface abundance is critical to myocyte survival after an ischemic attack and plays a role in OPC‐induced protection. They further suggest that the protection conferred by increased surface expression may be independent of ion transport.
Effects of MitoQ on Mitochondrial Function in Pressure Overload‐Induced Heart Failure
Authors: OˈConnell Kelly Anne , Dabkowski Erinne R , Faustino Rogerio , Xu Wenhong , Galvao Tatiana , Stanley William C
Published: June 2021

Heart failure (HF) increases reactive oxygen species (ROS) production by mitochondria, which may contribute to HF progression. We assessed the impact of a mitochondria‐targeted antioxidant, Mitoquinone (MitoQ), in HF induced by transverse aortic constriction (TAC). MitoQ was given from 6 to 14 weeks post‐surgery, and subsarcolemmal (SSM) and interfibrillar (IFM) mitochondria were isolated. TAC resulted in moderate severity HF, with an 84% increase in LV mass and a 22% decrease LV ejection fraction compared to sham (both p<0.05), with no effect of MitoQ treatment. MitoQ increased State 3 respiration in SSM by 13% (p<0.05), with no effect in IFM. Ca2+‐induced mitochondrial swelling was significantly greater in MitoQ vs. sham at a high but not low [Ca2+] in both SSM and IFM (p<0.05). ROS induced MPTP was accelerated by TAC, but unaffected by MitoQ. Flow cytometry analysis of size revealed smaller SSM with MitoQ but no effect on IFM. Further, MitoQ treatment increased membrane fluidity in SSM but not IFM. Together, these findings suggest that MitoQ treatment mainly affects SSM in TAC‐induced HF.
Beating anoxia: mitochondrial plasticity in the turtle heart
Authors: Galli Gina Lucia Jane , Richards Jeffrey
Published: June 2021

Freshwater turtles can survive without oxygen for several months. The cellular mechanisms that allow the turtle heart to survive without oxygen have remained almost totally unexplored. In particular, it is not known how the turtle heart avoids anoxic damage to the mitochondria. The objective of this study was to make a comprehensive analysis of mitochondrial function in chronically and acutely anoxic mitochondria from the heart of Trachemys scripta. Turtles were acclimated to 5°C under either normoxic or anoxic (2 weeks) conditions. Mitochondrial respiration, electron transport chain (ETC) activities, ADP affinity, enzyme activities, proton leak and membrane potential were measured in permeabilized cardiac fibres and isolated mitochondria. 2 weeks of anoxia led to a decrease in aerobic capacity and an increase in proton conductance (proton leak) of the mitochondrial membrane. The mechanism behind this plasticity was a downregulation of Complex V in the ETC. This strategy serves two purposes; to conserve ATP when energy is limited and to reduce the production of reactive oxygen species. Turtle heart mitochondria endured 20 min of simulated anoxia followed by reperfusion without any impact on subsequent ADP stimulated oxygen consumption, State IV respiration or respiratory control ratio. Thus, turtle mitochondria are robust and intrinsically tolerant to anoxia/reoxygenation.
Investigation of the role of 5‐HT1A and 5‐HT7 receptor in the Dorsal Raphé on sympathetic nerve drive in anaesthetized rats
Authors: Moore Christopher , Ramage Andrew G
Published: June 2021

Central 5‐HT1A and more recently 5‐HT7 receptors have been shown to play a role in cardiovascular regulation. A major site of these receptors is the dorsal raphé (DR), whose role in cardiovascular regulation is little understood. Experiments were carried out to determine the effects of activation of these receptors by microinjecting (volume 1 μl) 8‐OH‐DPAT and 5‐CT. In addition, the effects of activating (glutamate; 50 μ kg−1) and inhibiting (muscimol; 50 μg kg−1) these DR neurons were also investigated. Rats were anaesthetized with α‐chloralose (100 mg kg−1; i.v), neuromuscular blocked, artificially ventilated and instrumented to record BP, HR and renal nerve activity (RNA). Microinjections of 8‐OH‐DPAT (10 μg kg−1) caused a small delayed fall in BP −7 ± 2 mmHg and a delayed increase in RNA 42 ± 10%. Interestingly 5‐CT (1 μg kg−1) had no effect, but 10 μg kg−1 did cause a decrease, however this was similar to 10 μg kg−1 5‐CT i.v. Both glutamate and muscimol cause falls in BP, HR and RNA. The glutamate depressor action was found to be attenuated by previous injections of 8‐OH‐DPAT or WAY‐100635 (10 μg kg−1; noneffective alone) but not 5‐CT. This data suggests that both glutamatergic and GABAergic pathways in the DR are depressor, while inhibition of 5‐HT neurons has only a minor depressor action. Supported by BHF grant PG/07/119/24169
P2Y1‐receptors are expressed by CO2/H+‐insensitive neurons in the retrotrapezoid nucleus (RTN) and contribute to the peripheral drive to breathe
Authors: Wenker Ian Christopher , Takakura Ana , Moreira Thiago , Mulkey Daniel Kent
Published: June 2021

The chemical drive to breathe comes from central chemoreceptors that sense tissue CO2/H+, and peripheral chemoreceptors that sense arterial CO2/H+ and O2. Changes in CO2/H+ and O2 can trigger ATP release near the RTN, and ATP has been shown to modulate activity of RTN neurons, possibly by activation of P2Y1‐receptors (P2Y1‐R). Therefore, we hypothesize that P2Y1‐R represent the molecular basis for central and peripheral chemoreceptor integration at the level of the RTN. Here, we use in vivo and in vitro recording techniques to examine the role of P2Y1‐R expressed by RTN neurons in central and peripheral chemoreception. In vivo, bilateral injection of MRS2365, a P2Y1‐R specific agonist, into the RTN of anesthetized adult rats increased phrenic nerve amplitude 24% and frequency 31%, whereas application of the specific P2Y1‐R antagonist MRS2179 decreased the ventilatory response to peripheral chemoreceptor activation but not hypercapnia. In vitro, loose‐patch recordings of neurons in slices from rats (P7–12) show that baseline activity and CO2/H+‐sensitivity of chemoreceptors was unaffected by MRS2179 or MRS2365. Conversely, MRS2179 decreased baseline activity of non‐chemosensitive RTN neurons by 42 % and MRS2365 increased activity of these cells by 630 %. These results indicate that P2Y1‐R are functionally expressed in nonchemosensitive RTN neurons and contribute to peripheral chemoreception.
Differences between two inbred rat strains in the number of Kv 1.4 channel‐immunoreactive neurons in the nucleus tractus solitarius (NTS)
Authors: Martino Paul F , Olesiak S , Batuuka D , Riley D , Neumueller S , Marshall B D , Qian B , Hodges M R , Forster H V
Published: June 2021

Ventilatory sensitivity to hypercapnia is greater in Dahl salt‐sensitive (SS) rats than in Brown Norway (BN) inbred rats (J Appl Physiol). Since pH‐sensitive potassium ion (K+) channels are located within various chemosensitive nuclei including the nucleus of the solitary tract (NTS), and are postulated to contribute to CO2− H+ detection/signaling in chemosensitive neurons, we tested the hypothesis that there are more pH‐sensitive Kv 1.4 channel‐immunoreactive (ir) neurons within the NTS of SS than within the NTS of BN rats. The medullary sections (25 μm) containing the NTS from male and female BN and SS rats were stained with cresyl violet or with antibodies targeting Kv 1.4. Kv 1.4 channel‐ir neurons were quantified and compared with the total neurons in the region. The average number of Kv 1.4 channel‐ir neurons per hemisection was significantly (P < 0.05) greater in both male and female SS (n = 6 males and 6 females) than in the BN (n = 6 males and 6 females) rats. In addition, the percentage of Nissl stained neurons that express Kv 1.4 was statistically greater in SS male versus BN male rats. That trend however, was not observed in female SS and BN rats (P > 0.05). Our findings further support the hypothesis that a greater number of K+ channel‐ir neurons in the NTS of SS may contribute to their relatively greater sensitivity to CO2. (Supported by the Department of Veterans Affairs and NIH HL25739)
Central losartan attenuates CIH‐induced hypertension and FosB/ΔFosB expression in hypothalamic autonomic regions
Authors: Knight W David , Saxena Ashwini , Little Joel T , Dutta Mayurika , Cunningham J. Thomas
Published: June 2021

Chronic intermittent hypoxia (CIH) increases mean arterial pressure (MAP) and FosB/ΔFosB staining in central autonomic nuclei. To test the role of the brain RAS in CIH hypertension, rats were implanted with intracerebroventricular cannulae delivering losartan (ICVLOS: 1ug/hr) or vehicle (VEH) via mini‐osmotic pumps and telemetry devices for arterial pressure recording. A third group was given equimolar subcutaneous LOS (SCLOS) to differentiate between central and peripheral RAS effects. Rats were exposed to CIH for 7d then sacrificed for immunohistochemistry. ICV losartan had no effect on ΔMAP during CIH (VEH 5.9±0.8; ICVLOS 4.4±1.1; SCLOS 6.3±0.8 mmHg) but attenuated CIH‐induced increases in ΔMAP during the normoxic dark phase (VEH 6.7±0.8; ICVLOS 2.7±0.9; SCLOS 4.8±0.7 mmHg). Compared to VEH, ICVLOS and SCLOS attenuated FosB/ΔFosB staining in the organum vasculosum of the lamina terminalis (VEH 58±3; ICVLOS 23±6; SCLOS 37±7 cells/section). However, only ICVLOS attenuated staining in the median preoptic nucleus (VEH 31±5; ICVLOS 7±1; SCLOS 21±5 cells/section) and paraventricular (PVN) nucleus (VEH 32±7; ICVLOS 11±2; SCLOS 22± 3 cells/section). These data indicate that the central RAS contributes to the sustained, normoxic component of CIH‐induced hypertension and transcriptional activation of forebrain autonomic nuclei. Supported by P01 HL‐88052.
Neuronal Toxicity & Uptake of Cross‐Linked Copper/Zinc Superoxide Dismutase Nanozyme (cl‐SOD1 nano)
Authors: Savalia Krupa K , Manickam Devika S , Rosenbaugh Erin G , Kabanov Alexander V. , Zimmerman Matthew C
Published: June 2021

Excessive production of superoxide in the central nervous system (CNS) has been implicated in many brain‐related cardiovascular diseases, including hypertension. However, therapeutic potential of antioxidant therapies has been limited by restricted transport across the blood‐brain barrier and poor pharmacodynamics. To address these limitations, we developed cl‐SOD1 nano, a nanoformulated antioxidant polyion complex with SOD1 protein encaged in cross‐linked block copolymers. Here, we tested the hypothesis that cl‐SOD1 nano is more efficient in delivering SOD1 to central neurons than free SOD1 without inducing significant cellular toxicity. Central CATH.a neurons from mice were exposed (1, 3, 6, 12, 24hr) to cl‐SOD1 nano or free SOD1 to assess cell viability and neuronal uptake. Although confocal microscopy and western blot analysis suggest a time‐dependent increase in neuronal uptake of cl‐SOD1 nano as compared to free SOD1, exposure to cl‐SOD1 nano significantly (P<0.05) reduced cell survival vs. vehicle‐treated neurons 24, 48 and 72 hr (57±8%, 63±3%, 60±4% survival, respectively) after removal of cl‐SOD1 nano from neuronal culture. Further experiments must decipher which component of cl‐SOD1 nano or possible polymer degradation is inducing toxicity. These studies would provide insight for future SOD nanozyme formulations which may optimally counteract excessive superoxide in the CNS.

NIH P20RR021937
Mathematical Modeling of Myeloma Bone Disease
Authors: Ayati Bruce P
Published: June 2021

We exhibit the role mathematics can play in the study of multiple myeloma and the attendant dysregulated bone remodeling. We discuss our approach to the “local” interactions of the microenvironment (osteoclasts, osteoblasts, and stromal cells) and the myeloma tumor cells. The local model is then embedded in a spatially explicit model, based on level‐set equations, to represent the system at larger spatial scales.
The effect of high frequency oscillation (HFO) on the concentration of exhaled protein on canines
Authors: Tsai Hsiu-Wen , Condrey Jillian Alan , Adams Sherry , Davenport Paul W
Published: June 2021

Non‐invasive exhaled gas analysis is a safe and highly efficient strategy for the diagnosis of respiratory diseases. However, this method is limited by low concentration of targeted substances in exhaled air. In this study, we developed a HFO device that is hypothesized to vibrate the air inside of the lung, increasing the kinetic motion of lung substances and cause material lining the airways to be aerosolized. These substances will then enter the exhaled airstream and appear in the exhaled air samples. We used dogs undergoing routine surgery in this experiment. The exhaled air samples were collected by collecting filters attached to the endotracheal tube with or without 15 Hz, square wave HFO. Exhaled samples were collected for 10 min. Proteins trapped by the filters were extracted and analyzed by a protein quantitation kit. The results showed that the protein concentration during HFO was 32% greater than without HFO. It supports our hypothesis that 15Hz, square wave HFO increases the release of substances from the lung and increases the concentration of substances in exhaled air.
The postnatal development of the paranasal sinuses in the horse
Authors: Bragulla Hermann Heinrich , Homberger Dominique G , Wood Bradley M
Published: June 2021

In horses, paranasal sinuses form an elaborate system of interconnected cavities in the viscero‐and neurocranium. These sinuses are clinically significant, because sinus infections can affect vital structures, such as the optic nerve. To treat sinus infections, bony landmarks are used, such as the nasoincisive notch, for locating and accessing the sinuses via trepanation. In order to better understand the topographic and age‐related changes of the paranasal sinuses in relation to bony landmarks, we evaluated the postnatal development of the sinuses in horses, ages ranging from 3 days to 31 years old, via 3D reconstruction based on CT images. This non‐invasive method of virtual dissection avoids artifacts, such as those incurred due to incomplete filling of corrosion casts, because the paranasal sinuses can be segmented and reconstructed in their entirety. The reconstructed dimensions of the various paranasal sinuses are correlated to the growth of the cranium, as well as to the age of the horse, to determine whether there are size‐or age‐specific topographic relationships. For example, in the 6 years between 3‐year and 9‐year old horses, the volume of the caudal maxillary sinus increases 5 times, whereas the volume of the sphenopalatine sinus increases only 3 times and the volume of the neurocranial cavity increases only about 10 %. This study may also contribute to the understanding of NO production in the sinuses.
CT‐scan of the René Descartes (1596–1650) cranium
Authors: Le Floch-Prigent Patrice Pierre , Verdeille Stéphane , Froment Alain
Published: June 2021

The CT‐scan of the René DESCARTES cranium (collections du Musée National d'Histoire Naturelle à Paris) was performed on a Siemens sensation 64 apparatus. The acquisition was realized in the orbito‐meatal horizontal planes. Then the frontal and sagittal planes were reconstructed. The data were analyzed. The intracranial capacity was between 1413 and 1431 cc depending of the plane. The main interest of the CT‐scan was to perform a deep and accurate study without any damage to this rare sample.

Grant Funding Source : DEPARTMENT OF ANATOMY