scholarly journals Role of the endothelial glycocalyx in dromotropic, inotropic, and arrythmogenic effects of coronary flow

2000 ◽  
Vol 278 (1) ◽  
pp. H106-H116 ◽  
Author(s):  
Rafael Rubio ◽  
Guillermo Ceballos
Keyword(s):  
Coronary Flow ◽  
Parenchymal Cell ◽  
Cell Types ◽  
Surface Proteins ◽  
Inotropic Effect ◽  
Endothelial Glycocalyx ◽  
Inotropic Effects ◽  
Cardiac Functions ◽  
Endothelial Surface ◽  
Flow Effects

Coronary flow regulates cardiac functions, and it has been suggested that endothelial membrane glycosylated proteins are the primary shear stress mechanosensors. Our hypothesis was that if these proteins are the sensors for flow, then intracoronary perfusion of lectins or specific antibodies should differentially depress coronary flow-enhanced responses of different parenchymal cell types such as auricular-ventricular (A-V) nodal cells (dromotropic effect), contractile myocytes (inotropic effect), and junctional Purkinje-muscle cells (spontaneous ventricular rhythm). The coronary flow stimulatory effects on A-V delay and spontaneous ventricular rhythm were selectively depressed by six of eight lectins. None of the lectins depressed the coronary flow inotropic effect. Antibodies against endothelial surface proteins, αvβ5-integrin and sialyl-Lewisb glycan, depressed the dromotropic but not the inotropic effects of coronary flow, whereas the vascular cell adhesion molecule 1 antibody had no effect on the dromotropic, but enhanced the inotropic, effect. The fact that lectins and antibodies differentially depressed regional coronary flow effects suggests that there is a chemical distinctiveness in their intravascular endothelial cell surfaces. However, nonselective cross-linking of endothelial glycocalyx proteins with 2,000-kDa dextran-aldehyde or vitronectin indistinctively depressed the dromotropic and inotropic effects of coronary flow. These results indicate that coronary flow-induced stress acts on specific structures located in the capillary intravascular membrane glycocalyx.

Abstract 2192: Fcgamma Receptor II On Cardiomyocytes

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Christiane Trimpert ◽  
Stephan B Felix ◽  
Andreas Greinacher ◽  
Katrin Birkenmeier ◽  
Alexander Staudt
Keyword(s):  
Tyrosine Kinases ◽  
Kinase Inhibitors ◽  
Kinase Inhibitor ◽  
Negative Inotropic Effect ◽  
Cell Types ◽  
Inotropic Effect ◽  
Rat Cardiomyocytes ◽  
Inotropic Effects ◽  
Human Cardiomyocytes ◽  
Adult Rat

Introduction : Recently we detected the FcγII receptor on rat and human cardiomyocytes. Binding of cardiac antibodies obtained from DCM-patients to this receptor induced negative inotropic effects. The mechanism of these effects remains to be elucidated. Methods: Isolated adult rat cardiomyocytes stained with Fura-2-AM were field-stimulated (1 Hz, 12 V). The relative change of the calcium transients and systolic cell shortening due to superfusion with a polyclonal goat-antibody against the FcγII receptor (10 μg/ml) were recorded with a dual-excitation fluorescence microscope. For inhibition of possible involved tyrosine kinases we used PP2 (1μM) and specific syk-Kinase inhibitors. Results: Superfusion of rat cardiomyocytes with anti-FcγII-receptor antibody induces a negative inotropic effect. The tested concentrations (6 μg/ml, 8 μg/ml, 10 μg/ml and 16 μg/ml) show a clear dose-response-relationship. The contractility of the cells decreases after 2 min by −5,3%, −11,5%, −14,2% and −18,3% from baseline as well as the Ca 2+ -Ratio (−9,5%, −11,2%, −12,2%, −15,6%). The negative inotropic reaction could be blocked by preincubation of the cells with the tyrosine kinase inhibitor PP2 (change of contractility/Ca2+-Ratio from baseline: −1, 3%/−2,4%, p<0,001). Cells preincu-bated with specific inhibitors for syk-Kinases did not show a negative inotropic reaction after superfusion with the antibody (change of contractility/Ca 2+ -ratio from baseline +0,7%/−5,5%, p<0,05). A polyclonal goat control antibody (anti-CD45, c = 10 μg/ml)) did not trigger a reaction (change from baseline for contractility/Ca2+-Ratio: −3%/−2,4%, p<0,001). Conclusion: The inhibition of the negative inotropic effect of antibodies against FcγII receptor shows an involvement of Kinases in the signalling pathway like described for other cell types.

scholarly journals Effects of controlled ovarian stimulation on vascular barrier and endothelial glycocalyx: a pilot study

2021 ◽  
Author(s):  
Nikolai Hulde ◽  
N. Rogenhofer ◽  
F. Brettner ◽  
N. C. Eckert ◽  
I. Fetz ◽  
...  
Keyword(s):  
Ovarian Stimulation ◽  
Capillary Permeability ◽  
Serum Levels ◽  
Controlled Ovarian Stimulation ◽  
Endothelial Glycocalyx ◽  
Control Group ◽  
Vascular Integrity ◽  
Fluid Extravasation ◽  
Endothelial Surface ◽  
Infertility Patients

Abstract Purpose Controlled ovarian stimulation significantly amplifies the number of maturing and ovulated follicles as well as ovarian steroid production. The ovarian hyperstimulation syndrome (OHSS) increases capillary permeability and fluid extravasation. Vascular integrity intensely is regulated by an endothelial glycocalyx (EGX) and we have shown that ovulatory cycles are associated with shedding of EGX components. This study investigates if controlled ovarian stimulation impacts on the integrity of the endothelial glycocalyx as this might explain key pathomechanisms of the OHSS. Methods Serum levels of endothelial glycocalyx components of infertility patients (n=18) undergoing controlled ovarian stimulation were compared to a control group of healthy women with regular ovulatory cycles (n=17). Results Patients during luteal phases of controlled ovarian stimulation cycles as compared to normal ovulatory cycles showed significantly increased Syndecan-1 serum concentrations (12.6 ng/ml 6.1125th–19.1375th to 13.9 ng/ml 9.625th–28.975th; p=0.026), indicating shedding and degradation of the EGX. Conclusion A shedding of EGX components during ovarian stimulation has not yet been described. Our study suggests that ovarian stimulation may affect the integrity of the endothelial surface layer and increasing vascular permeability. This could explain key features of the OHSS and provide new ways of prevention of this serious condition of assisted reproduction.

scholarly journals The antiandrogen enzalutamide downregulates TMPRSS2 and reduces cellular entry of SARS-CoV-2 in human lung cells

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
D. A. Leach ◽  
A. Mohr ◽  
E. S. Giotis ◽  
E. Cil ◽  
A. M. Isac ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Human Lung ◽  
Cell Types ◽  
Receptor Activation ◽  
Surface Proteins ◽  
Mouse Lung ◽  
Lung Cells ◽  
Human Lung Cells ◽  
Cellular Entry ◽  
Experimental Data Analysis

AbstractSARS-CoV-2 attacks various organs, most destructively the lung, and cellular entry requires two host cell surface proteins: ACE2 and TMPRSS2. Downregulation of one or both of these is thus a potential therapeutic approach for COVID-19. TMPRSS2 is a known target of the androgen receptor, a ligand-activated transcription factor; androgen receptor activation increases TMPRSS2 levels in various tissues, most notably prostate. We show here that treatment with the antiandrogen enzalutamide—a well-tolerated drug widely used in advanced prostate cancer—reduces TMPRSS2 levels in human lung cells and in mouse lung. Importantly, antiandrogens significantly reduced SARS-CoV-2 entry and infection in lung cells. In support of this experimental data, analysis of existing datasets shows striking co-expression of AR and TMPRSS2, including in specific lung cell types targeted by SARS-CoV-2. Together, the data presented provides strong evidence to support clinical trials to assess the efficacy of antiandrogens as a treatment option for COVID-19.

scholarly journals Single Cell, Single Nucleus and Spatial RNA Sequencing of the Human Liver Identifies Hepatic Stellate Cell and Cholangiocyte Heterogeneity

2021 ◽  
Author(s):  
Tallulah S Andrews ◽  
Jawairia Atif ◽  
Jeff C Liu ◽  
Catia T Perciani ◽  
Xue-Zhong Ma ◽  
...  
Keyword(s):  
Single Cell ◽  
Rna Sequencing ◽  
Human Liver ◽  
Stellate Cell ◽  
Parenchymal Cell ◽  
Cell Types ◽  
Cell Populations ◽  
Healthy Human ◽  
Single Nucleus

The critical functions of the human liver are coordinated through the interactions of hepatic parenchymal and non-parenchymal cells. Recent advances in single cell transcriptional approaches have enabled an examination of the human liver with unprecedented resolution. However, dissociation related cell perturbation can limit the ability to fully capture the human liver's parenchymal cell fraction, which limits the ability to comprehensively profile this organ. Here, we report the transcriptional landscape of 73,295 cells from the human liver using matched single-cell RNA sequencing (scRNA-seq) and single-nucleus RNA sequencing (snRNA-seq). The addition of snRNA-seq enabled the characterization of interzonal hepatocytes at single-cell resolution, revealed the presence of rare subtypes of hepatic stellate cells previously only seen in disease, and detection of cholangiocyte progenitors that had only been observed during in vitro differentiation experiments. However, T and B lymphocytes and NK cells were only distinguishable using scRNA-seq, highlighting the importance of applying both technologies to obtain a complete map of tissue-resident cell-types. We validated the distinct spatial distribution of the hepatocyte, cholangiocyte and stellate cell populations by an independent spatial transcriptomics dataset and immunohistochemistry. Our study provides a systematic comparison of the transcriptomes captured by scRNA-seq and snRNA-seq and delivers a high-resolution map of the parenchymal cell populations in the healthy human liver.

scholarly journals Interaction of single-chain urokinase with its receptor induces the appearance and disappearance of binding epitopes within the resultant complex for other cell surface proteins

Blood ◽  
1996 ◽  
Vol 88 (2) ◽  
pp. 542-551 ◽  
Author(s):  
AA Higazi ◽  
RH Upson ◽  
RL Cohen ◽  
J Manuppello ◽  
J Bognacki ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Cell Surface ◽  
Binding Sites ◽  
Ldl Receptor ◽  
Cell Types ◽  
Surface Proteins ◽  
Single Chain ◽  
Cell Surface Proteins ◽  
Functional Changes ◽  
And Migration

Binding of urokinase-type plasminogen activator (uPA) to its glycosylphosphatidylinositol-anchored receptor (uPAR) initiates signal transduction, adhesion, and migration in certain cell types. To determine whether some of these activities may be mediated by associations between the uPA/uPAR complex and other cell surface proteins, we studied the binding of complexes composed of recombinant, soluble uPA receptor (suPAR) and single chain uPA (scuPA) to a cell line (LM-TK- fibroblasts) that does not express glycosylphosphatidylinositol (GPI)-anchored proteins to eliminate potential competition by endogenous uPA receptors. scuPA induced the binding of suPAR to LM-TK- cells. Binding of labeled suPAR/scuPA was inhibited by unlabeled complex, but not by scuPA or suPAR added separately, indicating cellular binding sites had been formed that are not present in either component. Binding of the complex was inhibited by low molecular weight uPA (LMW-uPA) indicating exposure of an epitope found normally in the isolated B chain of two chain uPA (tcuPA), but hidden in soluble scuPA. Binding of LMW-uPA was independent of its catalytic site and was associated with retention of its enzymatic activity. Additional cell binding epitopes were generated within suPAR itself by the aminoterminal fragment of scuPA, which itself does not bind to LM-TK- cells. When scuPA bound to suPAR, a binding site for alpha 2-macroglobulin receptor/LDL receptor-related protein (alpha 2 MR/LRP) was lost, while binding sites for cell-associated vitronectin and thrombospondin were induced. In accord with this, the internalization and degradation of cell-associated tcuPA and tcuPA-PAI- 1 complexes proceeded less efficiently in the presence of suPAR. Further, little degradation of suPAR was detected, suggesting that cell- bound complex dissociated during the initial stages of endocytosis. Thus, the interaction of scuPA with its receptor causes multiple functional changes within the complex including the dis-appearance of an epitope in scuPA involved in its clearance from the cell surface and the generation of novel epitopes that promote its binding to proteins involved in cell adhesion and signal transduction.

Human endothelial cells produce orosomucoid, an important component of the capillary barrier

1999 ◽  
Vol 276 (2) ◽  
pp. H530-H534 ◽  
Author(s):  
Jenny Sörensson ◽  
Göran L. Matejka ◽  
Maria Ohlson ◽  
Börje Haraldsson
Keyword(s):  
Endothelial Cells ◽  
Primary Cultures ◽  
Rnase Protection Assay ◽  
Cell Types ◽  
Endothelial Glycocalyx ◽  
Rt Pcr ◽  
Rnase Protection ◽  
Total Rna ◽  
Main Site ◽  
Charge Selectivity

The serum protein orosomucoid (α1-acid glycoprotein) is needed to maintain the high capillary permselectivity required for normal homeostasis. It is not known how the protein executes its action, but it seems to contribute to the charge barrier. Moreover, recent studies suggest that the endothelial glycocalyx is essential for the charge barrier. The main site of orosomucoid synthesis is the liver, but we wanted to explore the possibility that orosomucoid was synthesized in endothelial cells. Primary cultures of human microvascular endothelial cells (HMVEC) from dermal tissue were established. Human liver cells were used as positive controls, and total RNA was prepared from both cell types. Reverse transcription-polymerase chain reaction (RT-PCR) was performed and demonstrated orosomucoid expression. After RT-PCR, the identities of the PCR products were confirmed by sequencing. RNase protection assay performed on total RNA from the HMVEC confirmed the results from the RT-PCR, i.e., orosomucoid mRNA is expressed by endothelial cells. Synthesis of orosomucoid in both liver and endothelial cells was demonstrated by immunoprecipitation. In conclusion, endothelial cells normally produce orosomucoid, which is essential for capillary charge selectivity. We suggest that orosomucoid exerts its effect by interacting with other components of the endothelial glycocalyx.

Positive inotropic effects of low concentrations of leukotrienes C4 and D4 in rat heart

1990 ◽  
Vol 259 (4) ◽  
pp. H1239-H1246 ◽  
Author(s):  
M. Karmazyn ◽  
M. P. Moffat
Keyword(s):  
Calcium Channel ◽  
Positive Inotropic Effect ◽  
Negative Inotropic Effect ◽  
Bay K 8644 ◽  
Inotropic Effect ◽  
Receptor Interaction ◽  
Inotropic Effects ◽  
Coronary Pressure ◽  
Low Concentrations ◽  
Rat Hearts

We examined the effects of leukotrienes (LT) B4, C4, D4, and E4 (0.010-2.5 ng/ml) on contractile and coronary function in isolated rat hearts. Concentration-dependent effects were examined either by the cumulative addition of LTs or by addition of specific concentrations to individual preparations. Neither LTB4 nor LTE4 produced myocardial or coronary effects at any concentration, irrespective of addition protocol. At 0.010 ng/ml, both LTC4 and LTD4 produced an increase in force that was associated with a 30% elevation in coronary pressure. Further cumulative addition of either leukotriene resulted in a negative inotropic effect and a further increase in coronary pressure. In contrast, following single additions of LTC4 or LTD4 (0.01-0.50 ng/ml) a positive inotropic effect and an increased coronary pressure were observed. LTC4 or LTD4 at 0.5 ng/ml produced a negative inotropic effect in hearts pretreated with 0.01 ng/ml of LTD4 or LTC4, respectively. Reversal of this addition protocol resulted in a negative inotropic effect of either 0.01 ng/ml LTD4 or LTC4. Verapamil and nifedipine significantly attenuated the positive inotropic and coronary constricting effect of 0.5 ng/ml LTC4 and LTD4. The addition of either LT following BAY K 8644 resulted in a negative inotropic effect, in contrast to the positive inotropic influence seen with leukotriene alone. Our results demonstrate a positive inotropic effect of low concentrations of LTC4 and LTD4 concomitant with coronary artery constriction, a phenomenon determined by leukotriene addition protocols and suggestive of LTC4/LTD4 receptor interaction. The effects of calcium channel antagonists and BAY K 8644 on the inotropic response suggest a leukotriene-mediated activation of the calcium channel resulting in increased intracellular calcium concentrations.

scholarly journals Inotropic effects and changes in sodium and calcium contents associated with inhibition of monovalent cation active transport by ouabain in cultured myocardial cells.

1979 ◽  
Vol 74 (4) ◽  
pp. 479-494 ◽  
Author(s):  
S Biedert ◽  
W H Barry ◽  
T W Smith
Keyword(s):  
Active Transport ◽  
Culture Medium ◽  
Monovalent Cation ◽  
Inotropic Effect ◽  
Inotropic Effects ◽  
Ventricular Cells ◽  
Carrier Mechanism ◽  
Positive Inotropic Effects ◽  
Ouabain Inhibition ◽  
Cultured Myocardial Cells

Cultured monolayers of spontaneously contracting chick embryo ventricular cells were perfused with culture medium containing ouabain. Contractile state was monitored by an optical-video system recording amplitude and velocity of cell wall motion. Positive inotropic effects of 2.5 x 10(-7) to 10(-6) M ouabain were manifest within 1.5-2 min, and reached a stable plateau within 5-6 min. The inotropic effect was fully reversed within 5 min after washout of ouabain. Inhibition of uptake of 42K+ (or the K+ analog 86Rb+) and efflux of 24Na+ occurred 1.5-2 min after exposure to ouabain. The degree of inhibition of transport was closely related to the magnitude of the positive inotropic effect throughout the ouabain concentration range 10(-7) to 10(-6) M. After washout of ouabain from monolayers, the monovalent cation active transport rate returned to normal within 1 min. Thus, both the onset and offset of inotropic action of ouabain were closely related temporally to inhibition of the sodium pump. Exposure to ouabain caused significant increases in exchangeable Na and Ca contents that appeared to be developed within 5 min. These data support the hypothesis that inhibition of monovalent cation active transport by ouabain is causally related to the development of positive inotropy and are consistent with modulation of Ca content by intracellular Na+ via the Na+-Ca2+ exchange carrier mechanism.

scholarly journals Low-Phosphate-Dependent Invasion Resembles a General Way for Neisseria gonorrhoeae To Enter Host Cells

2006 ◽  
Vol 74 (7) ◽  
pp. 4266-4273 ◽  
Author(s):  
Christiane Kühlewein ◽  
Cindy Rechner ◽  
Thomas F. Meyer ◽  
Thomas Rudel
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Rho Gtpases ◽  
Wide Spectrum ◽  
Cell Types ◽  
Surface Proteins ◽  
Host Cells ◽  
Animal Origin ◽  
Target Cells ◽  
Pit Formation ◽  
Serious Disease

ABSTRACT Obligate human-pathogenic Neisseria gonorrhoeae expresses numerous variant surface proteins mediating adherence to and invasion of target cells. The invariant major outer membrane porin PorB of serotype A (P.IA) gonococci triggers invasion into Chang cells only if the medium is devoid of phosphate. Since gonococci expressing PorBIA are frequently isolated from patients with severe disseminating infections, the interaction initiated by the porin may be of major relevance for the development of this serious disease. Here, we investigated the low-phosphate-dependent invasion and compared it to the well-known pathways of entry initiated by Opa proteins. P.IA-triggered invasion requires clathrin-coated pit formation and the action of actin and Rho GTPases. However, in contrast to Opa-initiated invasion via heparan sulfate proteoglycans, microtubules, acidic sphingomyelinase, phosphatidylinositol 3-kinase, and myosin light chain kinase are not involved in this entry pathway. Nor are Src kinases required, as they are in invasion, e.g., via the CEACAM3 receptor. Invasion by PorBIA occurs in a wide spectrum of cell types, such as primary human epithelial and endothelial cells and in cancer cells of human and animal origin. Low-phosphate-dependent invasion is thus a pathway of gonococcal entry distinct from Opa-mediated invasion.

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