scholarly journals Extracellular SPARC improves cardiomyocyte contraction during health and disease

2018 ◽  
Author(s):  
Sophie Deckx ◽  
Daniel M. Johnson ◽  
Marieke Rienks ◽  
Paolo Carai ◽  
Elza van Deel ◽  
...  
Keyword(s):  
Cardiac Function ◽  
Cardiac Dysfunction ◽  
Matrix Protein ◽  
Contractile Function ◽  
Ex Vivo ◽  
Cardiac Fibroblasts ◽  
Cardiac Injury ◽  
Coxsackie Virus ◽  
Extracellular Matrix Protein

Secreted protein acidic and rich in cysteine (SPARC) is a non-structural extracellular matrix protein that regulates interactions between the matrix and neighboring cells. In the cardiovascular system, it is expressed by cardiac fibroblasts, endothelial cells, and in lower levels by ventricular cardiomyocytes. SPARC expression levels are increased upon myocardial injury and also during hypertrophy and fibrosis. We have previously shown that SPARC improves cardiac function after myocardial infarction by regulating post-synthetic procollagen processing, however whether SPARC directly affects cardiomyocyte contraction is still unknown. In this study we demonstrate a novel inotropic function for extracellular SPARC in the healthy heart as well as in the diseased state after myocarditis-induced cardiac dysfunction. We demonstrate SPARC presence on the cardiomyocyte membrane where it is co-localized with the integrin-beta1 and the integrin-linked kinase. Moreover, extracellular SPARC directly improves cardiomyocyte cell shortening ex vivo and cardiac function in vivo, both in healthy myocardium and during coxsackie virus-induced cardiac dysfunction. In conclusion, we demonstrate a novel inotropic function for SPARC in the heart, with a potential therapeutic application when myocyte contractile function is diminished such as that caused by a myocarditis-related cardiac injury.

scholarly journals Integrin-αvβ3 regulates thrombopoietin-mediated maintenance of hematopoietic stem cells

Blood ◽  
2012 ◽  
Vol 119 (1) ◽  
pp. 83-94 ◽  
Author(s):  
Terumasa Umemoto ◽  
Masayuki Yamato ◽  
Jun Ishihara ◽  
Yoshiko Shiratsuchi ◽  
Mika Utsumi ◽  
...  
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Matrix Protein ◽  
Ex Vivo ◽  
Extracellular Matrix Protein ◽  
Αvβ3 Integrin ◽  
Hematopoietic Stem ◽  
Β3 Integrin ◽  
Ex Vivo Culture

AbstractThroughout life, one's blood supply depends on sustained division of hematopoietic stem cells (HSCs) for self-renewal and differentiation. Within the bone marrow microenvironment, an adhesion-dependent or -independent niche system regulates HSC function. Here we show that a novel adhesion-dependent mechanism via integrin-β3 signaling contributes to HSC maintenance. Specific ligation of β3-integrin on HSCs using an antibody or extracellular matrix protein prevented loss of long-term repopulating (LTR) activity during ex vivo culture. The actions required activation of αvβ3-integrin “inside-out” signaling, which is dependent on thrombopoietin (TPO), an essential cytokine for activation of dormant HSCs. Subsequent “outside-in” signaling via phosphorylation of Tyr747 in the β3-subunit cytoplasmic domain was indispensable for TPO-dependent, but not stem cell factor-dependent, LTR activity in HSCs in vivo. This was accompanied with enhanced expression of Vps72, Mll1, and Runx1, 3 factors known to be critical for maintaining HSC activity. Thus, our findings demonstrate a mechanistic link between β3-integrin and TPO in HSCs, which may contribute to maintenance of LTR activity in vivo as well as during ex vivo culture.

Abstract 33: Cardiac Fibroblasts Reprogram Into Endothelial Like Cells in a p53 Dependent Manner After Acute Ischemic Cardiac Injury

2013 ◽  
Vol 33 (suppl_1) ◽  
Author(s):  
Eric Ubil ◽  
Arjun Deb
Keyword(s):  
Endothelial Cells ◽  
Ex Vivo ◽  
Cardiac Fibroblasts ◽  
Cardiac Injury ◽  
Border Zone ◽  
Immunofluorescent Staining ◽  
Serum Starvation ◽  
Dependent Manner ◽  
Post Injury

The mammalian heart exhibits poor regenerative capacity after acute ischemic injury and heals primarily by fibrosis. Recently, several groups have demonstrated that cardiac fibroblasts can be reprogrammed to adopt myogenic fates using exogenous transcription factors. However, the ability of cardiac fibroblasts to adopt specific cellular fates in the absence of exogenous factors is unclear. Here, we demonstrate that a subset of cardiac fibroblasts adopt endothelial characteristics after ischemic cardiac injury in the absence of any added factors. Using mice harboring genetically labeled fibroblasts (Col1a2CreERT:R26RTdTomato), we show that 34 +/- 3% (mean, SEM) of labeled cardiac fibroblasts in the injury border zone express endothelial markers such as VE-cadherin. Fibroblast derived endothelial cells comprised 25 +/- 2% of total and 8 +/- 2% of luminal endothelial cells at the border zone 3 days after injury. To better understand fibroblast-endothelial reprogramming we subjected cardiac fibroblasts to cellular stress (serum starvation) and found that they formed tubes on Matrigel and up-regulated endothelial specific genes (e.g. VE-cadherin, Flk1, Flt1) 6-20 fold. We show that reprogramming of fibroblasts to endothelial like cells ex vivo is p53 dependent. Inhibiting p53 activity by pharmacological means (Pifithrin-α) or genetic deletion in fibroblasts (Col1a2CreERT:p53fl/fl) led to a 94% decrease in Matrigel tube formation and 90% reduction in endothelial gene expression. Moreover, we observed that p53 levels in cardiac fibroblasts were more than 10-fold higher at the injury border zone using semi-quantitative immunofluorescent staining. Injection of a p53 activator after injury doubled p53 levels in cardiac fibroblasts and increased the rate of fibroblast-endothelial reprogramming by 43%. Enhanced fibroblast-endothelial reprogramming was also associated with decreased collagen deposition 3 days post injury. In summary, we show that cardiac fibroblasts are able to adopt endothelial cell like fates both in vivo and ex vivo in a p53 dependent manner. Manipulation of fibroblast to endothelial reprogramming could represent a novel therapeutic strategy to increase post infarct angiogenesis and enhance function in the injured heart.

Co-expression of skeletal and cardiac troponin T decreases mouse cardiac function

2008 ◽  
Vol 294 (1) ◽  
pp. C213-C222 ◽  
Author(s):  
Q.-Q. Huang ◽  
H. Z. Feng ◽  
J. Liu ◽  
J. Du ◽  
L. B. Stull ◽  
...  
Keyword(s):  
Cardiac Function ◽  
Contractile Function ◽  
Troponin T ◽  
Ex Vivo ◽  
Heart Function ◽  
Left Ventricular Pressure ◽  
Experimental System ◽  
Left Ventricular ◽  
Negative Effects

In contrast to skeletal muscles that simultaneously express multiple troponin T (TnT) isoforms, normal adult human cardiac muscle contains a single isoform of cardiac TnT. To understand the significance of myocardial TnT homogeneity, we examined the effect of TnT heterogeneity on heart function. Transgenic mouse hearts overexpressing a fast skeletal muscle TnT together with the endogenous cardiac TnT was investigated in vivo and ex vivo as an experimental system of concurrent presence of two classes of TnT in the adult cardiac muscle.This model of myocardial TnT heterogeneity produced pathogenic phenotypes: echocardiograph imaging detected age-progressive reductions of cardiac function; in vivo left ventricular pressure analysis showed decreased myocardial contractility; ex vivo analysis of isolated working heart preparations confirmed an intrinsic decrease of cardiac function in the absence of neurohumoral influence. The transgenic mice also showed chronic myocardial hypertrophy and degeneration. The dominantly negative effects of introducing a fast TnT into the cardiac thin filaments to produce two classes of Ca2+ regulatory units in the adult myocardium suggest that TnT heterogeneity decreases contractile function by disrupting the synchronized action during ventricular contraction that is normally activated as an electrophysiological syncytium.

Endurance exercise attenuates cardiotoxicity induced by androgen deprivation and doxorubicin

2014 ◽  
Vol 92 (5) ◽  
pp. 356-362 ◽  
Author(s):  
Traci L. Parry ◽  
David S. Hydock ◽  
Brock T. Jensen ◽  
Chia-Ying Lien ◽  
Carole M. Schneider ◽  
...  
Keyword(s):  
Cardiac Function ◽  
Endurance Exercise ◽  
Cardiac Dysfunction ◽  
Ex Vivo ◽  
Left Ventricular ◽  
Androgen Deprivation ◽  
Maximal Rate ◽  
Sprague Dawley ◽  
Developed Pressure

Doxorubicin (DOX) is associated with cardiac dysfunction and irreversible testicular damage. Androgen deprivation therapy (ADT) is administered prior to DOX treatment to preserve testicular function. However, ADT may exacerbate DOX-induced cardiac dysfunction. Exercise is cardioprotective, but the effects of exercise on cardiac function during combined ADT and DOX treatment are currently unknown. In this study, male Sprague–Dawley rats were randomly assigned to experimental groups: control (CON), ADT, DOX, or ADT+DOX. Animals received ADT or control implants on days 1 and 29 of the 56-day protocol. Animals remained sedentary (SED) or engaged in treadmill endurance exercise (TM) beginning on day 1. On day 15, the animals received DOX at 1 mg·(kg body mass)–1·d–1 by intraperitoneal injection for 10 consecutive days, or an equivalent volume of saline. On day 57, cardiac function was assessed in vivo and ex vivo. Animals treated with DOX alone, or with combined ADT+DOX, showed significant (P < 0.05) reductions in left ventricular developed pressure (–21% and –27%), maximal rate of pressure development (–29% and –32%), and maximal rate of pressure decline (25% and 31%), respectively when compared with the sedentary control animals. Endurance exercise training attenuated (P > 0.05) cardiac dysfunction associated with combined ADT+DOX treatment, indicating that exercise during simultaneous ADT+DOX treatment is cardioprotective.

scholarly journals Vascular KATP channels protect from cardiac dysfunction and preserve cardiac metabolism during endotoxemia

2020 ◽  
Vol 98 (8) ◽  
pp. 1149-1160
Author(s):  
Qadeer Aziz ◽  
Jianmin Chen ◽  
Amie J Moyes ◽  
Yiwen Li ◽  
Naomi A Anderson ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Cardiac Function ◽  
Cardiac Dysfunction ◽  
Ex Vivo ◽  
Critical Role ◽  
Lethal Dose ◽  
Systemic Infection ◽  
Cardiac Metabolism ◽  
Lipid Fatty Acid

Abstract KATP channels in the vasculature composed of Kir6.1 regulate vascular tone and may contribute to the pathogenesis of endotoxemia. We used mice with cell-specific deletion of Kir6.1 in smooth muscle (smKO) and endothelium (eKO) to investigate this question. We found that smKO mice had a significant survival disadvantage compared with their littermate controls when treated with a sub-lethal dose of lipopolysaccharide (LPS). All cohorts of mice became hypotensive following bacterial LPS administration; however, mean arterial pressure in WT mice recovered to normal levels, whereas smKO struggled to overcome LPS-induced hypotension. In vivo and ex vivo investigations revealed pronounced cardiac dysfunction in LPS-treated smKO, but not in eKO mice. Similar results were observed in a cecal slurry injection model. Metabolomic profiling of hearts revealed significantly reduced levels of metabolites involved in redox/energetics, TCA cycle, lipid/fatty acid and amino acid metabolism. Vascular smooth muscle-localised KATP channels have a critical role in the response to systemic infection by normalising cardiac function and haemodynamics through metabolic homeostasis. Key messages • Mice lacking vascular KATP channels are more susceptible to death from infection. • Absence of smooth muscle KATP channels depresses cardiac function during infection. • Cardiac dysfunction is accompanied by profound changes in cellular metabolites. • Findings from this study suggest a protective role for vascular KATP channels in response to systemic infection.

Abstract 77: Fibronectin Signals Through Pim-1 and β1 Integrin in Cardiac Progenitor Cells to Induce Proliferation and Protection

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Mathias H Konstandin ◽  
Haruhiro Toko ◽  
Mirko Volkers ◽  
Mercedes Quintana ◽  
Natalie Gude ◽  
...  
Keyword(s):  
Cell Death ◽  
Cardiac Function ◽  
Progenitor Cells ◽  
Matrix Protein ◽  
Extracellular Matrix Protein ◽  
Cardiac Progenitor Cells ◽  
Β1 Integrin ◽  
Dependent Manner ◽  
Integrin Receptor

Background: Cardiac Progenitor Cells (CPC) are pivotally involved in cardiac repair. Fibronectin (FN), an extracellular matrix protein, is highly expressed during cardiac development. In adult heart FN is a component of the cardiac stem cell niche and re-appears after myocardial infarction (MI). The role of FN signaling in CPC function and cardiac remodeling following MI has not been elucidated. We demonstrate here proliferative and protective effects of FN signaling in CPC as mediated by β1 integrin receptor and cardioprotective serine/threonine kinase Pim1. Methods: Cell death and proliferation of CPCs was measured using propidium iodide and CyQuant assays. Signaling pathways were analyzed by immunoblotting, qRT-PCR and siRNA depletion of targets. FN was localized in heart sections by immunohistochemistry and cardiac function assessed by echocardiography in control and conditional FN knockout (KO) mouse hearts following MI. Results: FN inhibits starvation and staurosporine induced cell death in CPCs and promotes proliferation in conjunction with induction of Pim1 expression. Protective and pro-proliferative effects of FN are abrogated by inhibition of Pim1 or deletion of β1 integrin receptor. In vivo CPC expansion correlates with FN expression following MI, and CPC localize to regions of up-regulated FN protein in the infarct. Cardiac function in control and KO mice remains equivalent up to 2 weeks post MI, however by 4 weeks KO heart function worsens compared to control as evidenced by ejection fraction values measuring 16.4 +/- 1.5% vs 26.6 +/- 1.8% at 12 weeks post MI in KO and control hearts, respectively. Conclusion: FN provides pro-survival and pro-proliferative effects to CPCs in a Pim1 kinase and β1 integrin dependent manner. CPCs and FN colocalize in vivo in an infarction injury model, while conditional KO of FN in mice leads to further impairment of cardiac function after MI. Taken together these results indicate previously unidentified cardioprotective and regenerative roles for FN in pathologically challenged heart.

scholarly journals Specific heparan sulfate modifications stabilize the synaptic organizer MADD-4/Punctin at C. elegans neuromuscular junctions

Genetics ◽  
2021 ◽  
Author(s):  
Mélissa Cizeron ◽  
Laure Granger ◽  
Hannes E B&Uuml;low ◽  
Jean-Louis Bessereau
Keyword(s):  
Heparan Sulfate ◽  
Matrix Protein ◽  
Neuromuscular Junctions ◽  
Core Protein ◽  
Extracellular Matrix Protein ◽  
Inhibitory Synapses ◽  
Single Chain ◽  
C Elegans ◽  
Sugar Chains

Abstract Heparan sulfate proteoglycans contribute to the structural organization of various neurochemical synapses. Depending on the system, their role involves either the core protein or the glycosaminoglycan chains. These linear sugar chains are extensively modified by heparan sulfate modification enzymes, resulting in highly diverse molecules. Specific modifications of glycosaminoglycan chains may thus contribute to a sugar code involved in synapse specificity. Caenorhabditis elegans is particularly useful to address this question because of the low level of genomic redundancy of these enzymes, as opposed to mammals. Here, we systematically mutated the genes encoding heparan sulfate modification enzymes in C. elegans and analyzed their impact on excitatory and inhibitory neuromuscular junctions. Using single chain antibodies that recognize different heparan sulfate modification patterns, we show in vivo that these two heparan sulfate epitopes are carried by the SDN-1 core protein, the unique C. elegans syndecan orthologue, at neuromuscular junctions. Intriguingly, these antibodies differentially bind to excitatory and inhibitory synapses, implying unique heparan sulfate modification patterns at different neuromuscular junctions. Moreover, while most enzymes are individually dispensable for proper organization of neuromuscular junctions, we show that 3-O-sulfation of SDN-1 is required to maintain wild-type levels of the extracellular matrix protein MADD-4/Punctin, a central synaptic organizer that defines the identity of excitatory and inhibitory synaptic domains at the plasma membrane of muscle cells.

Treatment of type 2 diabetic db/db mice with a novel PPARγ agonist improves cardiac metabolism but not contractile function

2004 ◽  
Vol 286 (3) ◽  
pp. E449-E455 ◽  
Author(s):  
Andrew N. Carley ◽  
Lisa M. Semeniuk ◽  
Yakhin Shimoni ◽  
Ellen Aasum ◽  
Terje S. Larsen ◽  
...  
Keyword(s):  
Contractile Function ◽  
Ex Vivo ◽  
Metabolic Changes ◽  
Pparγ Agonist ◽  
Perfused Hearts ◽  
Type 2 Diabetic ◽  
Contractile Performance ◽  
Exogenous Substrates

Hearts from insulin-resistant type 2 diabetic db/db mice exhibit features of a diabetic cardiomyopathy with altered metabolism of exogenous substrates and reduced contractile performance. Therefore, the effect of chronic oral administration of 2-(2-(4-phenoxy-2-propylphenoxy)ethyl)indole-5-acetic acid (COOH), a novel ligand for peroxisome proliferator-activated receptor-γ that produces insulin sensitization, to db/db mice (30 mg/kg for 6 wk) on cardiac function was assessed. COOH treatment reduced blood glucose from 27 mM in untreated db/db mice to a normal level of 10 mM. Insulin-stimulated glucose uptake was enhanced in cardiomyocytes from COOH-treated db/db hearts. Working perfused hearts from COOH-treated db/db mice demonstrated metabolic changes with enhanced glucose oxidation and decreased palmitate oxidation. However, COOH treatment did not improve contractile performance assessed with ex vivo perfused hearts and in vivo by echocardiography. The reduced outward K+ currents in diabetic cardiomyocytes were still attenuated after COOH. Metabolic changes in COOH-treated db/db hearts are most likely indirect, secondary to changes in supply of exogenous substrates in vivo and insulin sensitization.

scholarly journals Low-Intensity Pulsed Ultrasound Promotes Autophagy-Mediated Migration of Mesenchymal Stem Cells and Cartilage Repair

2021 ◽  
Vol 30 ◽  
pp. 096368972098614
Author(s):  
Peng Xia ◽  
Xinwei Wang ◽  
Qi Wang ◽  
Xiaoju Wang ◽  
Qiang Lin ◽  
...  
Keyword(s):  
Cartilage Repair ◽  
Matrix Protein ◽  
Extracellular Matrix Protein ◽  
Histopathological Analysis ◽  
Pulsed Ultrasound ◽  
Low Intensity Pulsed Ultrasound ◽  
Low Intensity ◽  
Autophagy Inhibitor

Mesenchymal stem cell (MSC) migration is promoted by low-intensity pulsed ultrasound (LIPUS), but its mechanism is unclear. Since autophagy is known to regulate cell migration, our study aimed to investigate if LIPUS promotes the migration of MSCs via autophagy regulation. We also aimed to investigate the effects of intra-articular injection of MSCs following LIPUS stimulation on osteoarthritis (OA) cartilage. For the in vitro study, rat bone marrow-derived MSCs were treated with an autophagy inhibitor or agonist, and then they were stimulated by LIPUS. Migration of MSCs was detected by transwell migration assays, and stromal cell-derived factor-1 (SDF-1) and C-X-C chemokine receptor type 4 (CXCR4) protein levels were quantified. For the in vivo study, a rat knee OA model was generated and treated with LIPUS after an intra-articular injection of MSCs with autophagy inhibitor added. The cartilage repair was assessed by histopathological analysis and extracellular matrix protein expression. The in vitro results suggest that LIPUS increased the expression of SDF-1 and CXCR4, and it promoted MSC migration. These effects were inhibited and enhanced by autophagy inhibitor and agonist, respectively. The in vivo results demonstrate that LIPUS significantly enhanced the cartilage repair effects of MSCs on OA, but these effects were blocked by autophagy inhibitor. Our results suggest that the migration of MSCs was enhanced by LIPUS through the activation autophagy, and LIPUS improved the protective effect of MSCs on OA cartilage via autophagy regulation.

Contrasting migratory response of astrocytoma cells to tenascin mediated by different integrins

1996 ◽  
Vol 109 (8) ◽  
pp. 2161-2168 ◽  
Author(s):  
A. Giese ◽  
M.A. Loo ◽  
S.A. Norman ◽  
S. Treasurywala ◽  
M.E. Berens
Keyword(s):  
Cell Adhesion ◽  
Matrix Protein ◽  
Glioma Cells ◽  
Extracellular Matrix Protein ◽  
Integrin Receptors ◽  
Migration Assay ◽  
Dose Dependent Fashion ◽  
Beta 1 Integrin

Tenascin, an extracellular matrix protein, is expressed in human gliomas in vitro and in vivo. The distribution of tenascin at the invasive edge of these tumors, even surrounding solitary invading cells, suggests a role for this protein as a regulator of glioma cell migration. We tested whether purified tenascin, passively deposited on surfaces, influenced the adhesion or migration of a human gliomaderived cell line, SF-767. Adhesion of glioma cells to tenascin increased in a dose-dependent fashion up to a coating concentration of 10 micrograms/ml. Higher coating concentrations resulted in progressively fewer cells attaching. Cell adhesion could be blocked to basal levels using anti-beta 1 integrin antibodies. In contrast, when anti-alpha v antibodies were added to the medium of cells on tenascin, cell adhesion was enhanced slightly. Using a microliter scale migration assay, we found that cell motility on tenascin was dose dependently stimulated at coating concentrations of 1 and 3 micrograms/ml, but migration was inhibited below levels of non-specific motility when tested at coating concentrations of 30 and 100 micrograms/ml. Migration on permissive concentrations of tenascin could be reversibly inhibited with anti-beta 1, while treatment with anti-alpha v antibodies increased migration rates. We conclude that SF-767 glioma cells express two separate integrin receptors that mediate contrasting adhesive and migratory responses to tenascin.

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