bluuebunny/crossref_metadata_2025_split huggingface dataset:
Endothelial SIRT1 prevents age‐induced impairment of vasodilator responses by enhancing the expression and activity of soluble guanylyl cyclase
Authors: Wang Yu , Guo Yumeng , Xu Cheng , Man Andy WC. , Vanhoutte Paul M. 
Published: June 2021

RationaleAged arteries are characterized by attenuated vasodilator and enhanced vasoconstrictor responses, which contribute to endothelial dysfunction in vascular diseases such as arterial hypertension, atherosclerosis and heart failure. SIRT1 is a longevity regulator exerting protective functions against vascular ageing, although the underlying mechanisms remain largely unknown.ObjectiveThe present study was designed to elucidate the signaling pathways involved in endothelial SIRT1‐mediated vasodilator responses during arterial aging. In particular, the contributions of nitric oxide (NO), endothelial NO synthase (eNOS), cyclooxygenase (COX) and/or soluble guanylyl cyclase (sGC) were examined.Methods and ResultsWild type (WT) or endothelial NO synthase knockout (eKO) mice were cross‐bred with those overexpressing human SIRT1 selectively in the vascular endothelium (EC‐SIRT1). Arteries were collected from the four groups of mice (WT, EC‐SIRT1, eKO and eKO‐SIRT1) to measure isometric relaxations/contractions in response to various pharmacological agents. In arteries of WT animals, decreased NO bioavailability, hyper‐activated COX signaling and downregulated sGC expression/activity collectively contributed to the increased vasoconstrictor and decreased vasodilator responses during ageing. Arteries of EC‐SIRT1 mice were protected from ageing‐induced alterations in smooth muscle relaxation/contraction and the vasodilator responses. Overexpression of endothelial SIRT1 did not block the reduction in NO bioavailability, but attenuated the hyper‐activation of COX‐2; the latter effect resulted in an inhibition of endothelium‐dependent contractions in arteries of EC‐SIRT1 and eKO‐SIRT1 mice. The sGC β1 subunit was significantly upregulated by endothelial overexpression of SIRT1 and the expression remained higher in arteries of old EC‐SIRT1 than those of age‐matched WT mice. Disruption of endothelial SIRT1 function downregulated sGC β1 expression. Moreover, overexpression of endothelial SIRT1 enhanced the relaxations to NO‐independent sGC stimulators in arteries of EC‐SIRT1 and eKO‐SIRT1 mice.ConclusionsEndothelial SIRT1 prevents age‐induced impairment of vasodilatation largely by inhibiting COX‐2‐mediated endothelium‐dependent contractions and enhancing sGC‐mediated smooth muscle relaxation, independently of eNOS and NO signaling.Support or Funding InformationThis work was financially supported by the grants from Research Grant Council of Hong Kong (780613M and 17121714), Hong Kong Health and Medical Research Fund (13142651 and 13142641), Collaborative Research Fund of Hong Kong (C7055‐14G) and the National Basic Research Program of China (973 Program 2015CB553603).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Inhibition of acid sphingomyelinase‐mediated autophagic flux contributes to amitriptyline‐induced perturbation of tube formation in murine endothelial cells
Authors: Guan Yinglu , Li Xiang , Koka Saisudha , Zhang Yang 
Published: June 2021

Amitriptyline is an inhibitor of lysosomal acid sphingomyelinase (gene symbol Smpd1) and a well‐known tricyclic anti‐depressant with cardiovascular side effects. We previously reported that loss of acid sphingomyelinase function leads to defective autophagic flux and enhanced dedifferentiation in vascular smooth muscle cells. However, it remains unknown whether amitriptyline has any cardiovascular side effects on the angiogenic capability of vascular endothelial cells and whether such effect is associated with impaired autophagy signaling pathways. Using an aortic ring assay, we demonstrated that the wild‐type aortas treated with amitriptyline or Smpd1+/− aortas exhibited decreased endothelial tube outgrowth from small slices of aorta embedded in Matrigel indicating attenuated ex vivo angiogenesis. Similarly, amitriptyline or Smpd1 gene silencing perturbed the tube formation capability of cultured mouse microvascular endothelial cells (MVECs). The inhibitory effect of amitriptyline on angiogenesis in MVECs was correlated with decreased activation of angiogenic signaling (phosphorylation of eNOS, Akt, and Erk1/2) and reduced endothelial cell proliferation. Mechanistically, amitriptyline alone had no effect on autophagy induction in MVECs but inhibited autophagic flux as shown by increased expression of LC3B and p62. Blockade of autophagic flux by lysosome function inhibitor bafilomycin or chloroquine mimics the effects of amitriptyline on angiogenic signaling, proliferation, and tube formation in MVECs. Collectively, these data suggest that defective acid sphingomyelinase‐mediated autophagic flux contributes to the cardiovascular side effects and toxicity of amitriptyline on proliferation and angiogenic capability of vascular endothelial cells.Support or Funding InformationNational Heart, Lung, and Blood Institute grants (HL122769, HL122937)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Biphasic Electrical Stimulation Promotes Insulin Release
Authors: Siegel David , Thompson David , Mower Morton , Ross David 
Published: June 2021

Biphasic (anodal pulse followed immediately by a cathodal pulse) electrical stimulation (10Hz, 5 ms duration) of rat insulinoma (Ins‐1) cells resulted in a 2–3‐fold increase in insulin release over 30 min that was stimulation period‐ and voltage‐dependent. Electrical stimulation of tissue culture medium (in the absence of cells) did not increase insulin release when subsequently added to cells, confirming that the insulin released by electrical stimulation was not due to substances generated by the culture medium. Electrical stimulation‐induced insulin release occurred in the absence or presence of glucose. Calcium channel blockade (using nifedipine or verapamil) inhibited basal insulin secretion and insulin secretion evoked by electrical stimulation, demonstrating that electrical stimulation‐induced insulin release involved activation of voltage‐dependent calcium channels and was not a non‐specific effect of stimulation on the plasma membrane. Basal insulin secretion and the increase in insulin release induced by electrical stimulation were also inhibited by the mitochondrial poisons antimycin A or oligomycin A, suggesting a role for mitochondrial function in insulin secretion. Electrical stimulation of cells also resulted in a more pronounced uptake of MitoTracker Red by mitochondria, indicating a more negative inner mitochondrial membrane potential. The failure of cells to accumulate the fluorogenic dye Cytotox green confirmed that electrical stimulation was not significantly disrupting the plasma membrane or inducing overt toxicity to the cells during the period of stimulation. These results provide further evidence that biphasic electrical stimulation can exert significant biological effects and elicit insulin release in a manner that is dependent upon mitochondrial activity and calcium channel activation but independent of glucose.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Multi‐Omic Approach to Identifying Altered Metabolic and Signaling Pathways in the Mouse Heart with Chronic Exposure to Atypical Antipsychotic Medications
Authors: Beauchemin Megan , Nevola Kathleen , Guntur Anyonya R. , Barlow Deborah , Le Phuong T. , Vary Calvin , Motyl Katherine J. , Duarte Christine , Houseknecht Karen L. 
Published: June 2021

Atypical (AA) antipsychotic drugs, including Risperidone (RIS) and Olanzapine (OLAN), cause cardiac arrhythmia and significant endocrine and metabolic risk factors for cardiovascular disease, including obesity, insulin resistance, hyperglycemia, and dyslipidemia. AA drugs have complex pharmacology, antagonizing G‐protein coupled receptors including: dopamine, serotonin, α‐adrenergic and muscarinic receptors. However, the underlying pharmacology linking cardiovascular morbidities to AA therapy is unknown. We hypothesize that AAs may alter cardiac energy metabolism and present early gene expression markers in the pathogenesis to cardiovascular disease. In this study we aim to investigate the mechanisms by which AAs may promote cardiometabolic dysfunction. Male B6 mice were dosed daily with either 5 mg/kg OLAN or 1 mg/kg RIS or vehicle control (V) for 4 weeks and chronic effects of AAs were assessed in whole heart ventricles by RNAseq, miRNAseq and Proteomic analysis. Results suggest changes in transcriptomic and proteomic profiles and in the mouse heart with chronic exposure to AAs relating to mitochondrial dysfunction, lipid oxidation and metabolism, contractility, cardiac hypertrophy and PPAR signaling. Further pathway analysis of these data sets using Ingenuity Pathway Analysis revealed altered canonical pathways and disease and function that are consistent between the RIS and OLAN treated groups compared to V. To further investigate the effect of AA treatment on cardiac mitochondrial function, cardiac mitochondria were isolated from female B6 mice dosed 4 weeks daily with V or 0.75 mg/kg RIS and oxygen consumption studies were performed on the XF24 extracellular flux analyzer (Agilent) to measure various respiratory states. Isolated mitochondria were well coupled and showed a RCR (OCRADP/OCROligo) of ~ 3. RIS treatment led to an increase in State II (Succinate) and State III (phosphorylating) respiration compared to V. In conclusion, our data demonstrate chronic effects of AAs on cardiac mitochondrial function and bioenergetics and indicators of cardiac function.Support or Funding InformationThis work was funded in part by NIH grant DK095413 awarded to KH and NIH grant AR067858 awarded to KJM.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Protective RhoA Signaling Regulates Drp1 and Mitochondrial Fission in Cardiomyocytes
Authors: Brand Cameron S. , Tan Valerie P. , Brown Joan Heller , Miyamoto Shigeki 
Published: June 2021

Cardiac ischemia/reperfusion injury occurs due to oxidative stress resulting from loss of blood flow and its subsequent restoration. Oxidative stress leads to dysfunction and death of cardiomyocytes, increasing risk of progression to heart failure. We have shown previously that signaling through activation of the small G‐protein RhoA protects against ischemia/reperfusion injury by blocking pro‐apoptotic mitochondrial signals in cardiomyocytes. Alterations in mitochondrial dynamics, in particular mitochondrial fission, have been suggested to play a role in cardioprotection. We tested the hypothesis that activated RhoA signaling also regulates mitochondrial fission in cardiomyocytes. The protein Drp1 translocates from the cytosol to the mitochondria to promote fission. Our studies show that adenoviral expression of active RhoA in cardiomyocytes stimulates phosphorylation of Drp1 at serine‐616, a phosphorylation residue associated with increased translocation of Drp1 to the mitochondria. Accordingly, active RhoA also increases Drp1 protein levels in mitochondrial fractions. Both responses are blocked by inhibition of ROCK, a kinase downstream of active RhoA. Endogenous RhoA activation by the GPCR agonist sphingosine‐1‐phosphate (S1P), a lysophospholipid signaling ligand associated with cardioprotection, also increases Drp1 phosphorylation and mitochondrial Drp1 through the S1P3 receptor subtype. Consistent with the role of mitochondrial Drp1 in fission, expression of active RhoA in cardiomyocytes promotes accumulation of smaller mitochondria through ROCK and Drp1, as assessed by fluorescence confocal microscopy. A Drp1 S616A mutant is not phosphorylated and, when expressed in cardiomyocytes, did not increase in mitochondrial fractions in response to active RhoA. In addition, expression of mutant Drp1 inhibits mitochondrial fission in response to active RhoA. Oxidative stress, induced by hydrogen peroxide, leads to cardiomyocyte cell death which is attenuated by activated RhoA. This protective effect of RhoA activation is blocked by siRNA knockdown of Drp1. Taken together, our findings demonstrate that RhoA activation can regulate Drp1 to induce mitochondrial fission, and that this response is involved in cardioprotection due to RhoA. We propose regulation of Drp1 by RhoA activation as a novel mechanism to provide protection in response to acute cardiomyocyte injury.Support or Funding InformationThis research was funded by NIH grants T32HL007444 (CSB) and R37HL028143 (JHB).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Reprogramming Human Cardiac Progenitor Cells into Pacemaker Cells for Heart Repair
Authors: Raghunathan Suchi , Iyer Dinakar , Potaman Vladimir , Schwartz Robert J. , McConnell Bradley K. 
Published: June 2021

Heart Failure (HF) accounts for 5.7 million deaths annually, which often are the result of acute or chronic ischemic injury due to myocardial infarction (MI). MI is associated with cardiomyocyte death succeeded by scar tissue formation. This scar tissue serves as a mechanical barrier and prevents normal electrical conductivity through the ventricles, thus contributing to the development of arrhythmias. Various stem cell therapies for cardiac repair are directed towards replacing injured myocardium with healthy cardiomyocytes. However, a primary concern with these therapies is their inability to synchronize electromechanically with the recipient myocardium, leading to arrhythmia and aggravating HF symptoms. Our study objective was to use a novel reprogramming strategy to convert human adipogenic mesenchymal stem cells (hADMSCs) first into cardiac progenitor cells (CPCs) and then into conducting Pacemaker‐like cells. Previously, we have shown successful reprogramming of hADMSCs to form CPCs using human transcription factors ETS2 and MESP1. We demonstrated cardiomyocyte phenotype based on gene expression, calcium transients, histology, and polarization wave conduction maps. Interestingly in our current studies, we have optimized a unique cocktail of transcription factors for reprogramming of CPCs into Pacemaker‐like cells using lentiviral vectors. The CPCs treated with transcription factor combinations were initially screened for Pacemaker‐like cells by FACS sorting for mcherry reporter gene specific for pacemaker cells. Following which we assayed these cells for pacemaker marker genes. We observed a robust induction of Pacemaker marker genes, by qPCR gene expression assays. We then validated the functional efficiency of Pacemaker‐like cells in‐vitro through voltage patch clamp recording. Interestingly, the patch clamp recording of the Pacemaker‐like cells exhibited “funny currents” demonstrating the functional characteristic of pacemaker cells. The characteristic of these conduction cells will be further validated by optical mapping in ex‐vivo studies. These studies will facilitate the development of an optimal Pacemaker‐like cell‐based therapy within failing hearts through the recovery of lost contractile and electrical function between cardiomyocytes.Support or Funding InformationThe National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes ofHealth (NIH);Center for the Advancement of Science in Space (CASIS)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Tiger nut extracts inhibit cell migration, RhoA, and RhoC GTPases, but induce Rac1/2/3 in MCF7 and MDA‐MB231 cancer‐origin cell lines
Authors: Achoribo Seyram Elom , ONG Ming Thong 
Published: June 2021

Background/AimsBreast cancer is the most common female cancer worldwide. The high mortality of breast cancer patients is increasing over the years due to the late stage discovery of the cancer when the cancer cells may have already metastasized. In many developing and underdeveloped countries such as Ghana, the delay in cancer detection is partly due to the cost of the various treatments available which forced the women to first fall on orthodox medicine or herbal products. A proper investigation and mechanism of action of known medicinal plants to help alleviate this burden is therefore needed. Tiger nut is an underutilized crop in Ghana, with high nutritional values, but consumed raw as snack or blended for its milk. A study on its antioxidant and cytotoxicity effects showed that it has an anti‐proliferative effect on MCF7 and MDA‐MB‐231 breast cancer‐origin cell lines. This work investigated the effects of Tiger nut extracts on the migration and invasion of the mentioned cell lines, and on the Rho GTPase pathways.MethodologyCell lines were cultured in DMEM (Low glucose) supplemented with 10 % FBS, and 1 % penicillin. The migration effect was studied by the scratching assay where plated cells were wounded, treated, incubated and pictures taken at 0 h, 12 h, and 24 hours time points. The invasion assay was performed using Matrigel invasion kits on MDA‐MB‐231. Finally, cytoplasmic proteins were extracted by lysing the cells with Thermo‐Fisher mper lysis buffer and Western blotted for Rho A, Rho C, and rac1/2/3.ResultsAqueous and Ethanol extracts have been found to inhibit the migration of the investigated cell lines. However, only ethanolic extract was found to reduce the invasiveness of MDA‐MB‐231 at almost 50 %. Rho A, and Rho C were down‐regulated by all extracts whereas Rac1/2/3 was up‐regulated in MCF7.ConclusionRho A and Rho C are known to positively contribute to tumour progression. Their down‐regulation might therefore be responsible for the inhibition in cell migration observed. Even though the over expression of Rac may assemble lamellipodia at the leading edge of the cell, the down regulation of the Rho A, and C could not generate the contractile force needed to migrate. Thus, the cell will be static or round up in case of absence of Rho B, which may be the reason of the anti‐proliferative behaviour observed from previous studies.Support or Funding InformationThe work was supported by Universiti Sains Malaysia. Seyram Elom Achoribo is recipient of The World Academic of Sciences‐Universiti Sains Malaysia (TWAS‐USM) fellowship.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Omega‐3 polyunsaturated fatty acids protect monocytes adhesion to endothelial cells induced by Mac‐1 expression through FFA4 in monocytes
Authors: Lee Seung‐Jin , Im Dong‐Soon 
Published: June 2021

A G protein‐coupled receptor (GPCR) named free fatty acid receptor 4 (FFA4, also known as GPR120) was found to act as a GPCR for omega‐3 polyunsaturated fatty acids (n‐3 PUFA). Recently, FFA4 is known to participate in the progression of atherosclerosis, however, the underlying mechanisms are unclear. Thus, this study investigated the molecular mechanisms responsible for monocyte adhesion to the vascular endothelium, which is a key early event in macrophage foam cell formation. In ex vivo study, LPS‐induced the primary monocyte adhesion to the vascular endothelial cells were significantly attenuated by pretreatment of EPA and DHA, a representative n‐3 PUFA. This EPA and DHA‐induced inhibition were blunted by primary monocytes isolated from FFA4 (−/−) mice. In in vitro study, The LPS‐induced monocyte adhesion to the endothelial cells and adhesion molecule, Mac‐1 expression were significantly attenuated by pretreatment of EPA and DHA in monocytes. This EPA and DHA‐induced inhibition was blunted by pretreatment of AH7614 (a FFA4 antagonist) and by transfection of FFA4 siRNA, suggesting a pivotal role of FFA4 on LPS‐induced monocyte adhesion to the endothelial cells and Mac‐1 expression. In addition, in promoter activity analysis and chromatin immunoprecipitation assays to identify transcription factors involved in EPA and DHA inhibited LPS‐induced Mac‐1 expression, both AP‐1 and NF‐κB played central roles to increase Mac‐1 transcription in LPS‐treated monocytes. The results of this study suggest that n‐3 PUFA protect monocyte adhesion to vascular endothelial cells and Mac‐1 expression via signaling pathways involving AP‐1 and NF‐κB by activating FFA4 in monocytes, leading to increased foam cell formation in the development of atherosclerosis.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Diuretic Effect of Cassia occidentalis Leaf and Seed Extracts in Sprague Dawley Rats
Authors: Blair Trisha Alexandria , Thomas Everton , Lindo Lisa , McGrowder Donovon , Singh Paul 
Published: June 2021

ObjectiveTo evaluate the diuretic activity of Cassia occidentalis leaf and seed extracts, and to determine their effects on AST and ALP levels in Sprague Dawley rats.MethodDiuretic activity of hexane, ethyl acetate, methanol and aqueous extracts from the leaves and seeds of Cassia occidentalis (100 mg/kg) were evaluated using the Lipschitz model in Sprague Dawley rats. (n=6). Frusemide (20 mg/kg) was used as the positive control. All substances were administered orally. Animals were placed in metabolism cages and urine collected over a 24 hrs period. Results were represented as urine volume per body weight (mL/kg). Sodium, potassium and chloride ion concentrations in urine were also determined. Blood was collected before and 24 hrs after administration of extracts to obtain AST and ALP levels using an auto analyser system.ResultsThe mean urine volume collected from groups administered methanol and aqueous extracts from leaves of Cassia occidentalis were 19.02 mL/kg (p=0.009) and 18.81 mL/kg (p=0.017) respectively. Aqueous extract from the seeds of Cassia occidentalis was the only extract from the seeds that produced an increase in mean urine volume (20.78 mL/kg; p=0.003). Urine volume produce by all three extracts were significantly higher when compared to control (9.80 mL/kg). Sodium, potassium and chloride ion urine concentrations significantly increased after the administration of methanol and aqueous extract from the leaves of Cassia occidentalis. Frusemide produced a mean urine volume of 39.48 mL/kg (p<0.001) and an increase in sodium, potassium and chloride ions concentration.All groups were observed to have a reduction in AST and ALP levels.ConclusionThe study revealed that methanol and aqueous extracts from the leaves of Cassia occidentalis have diuretic effects. These extracts also significantly increased urine levels of sodium, potassium and chloride and reduced AST and ALP levels.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.