Abstract 21: Stiffness-Dependent Notch1 Activation Regulates Cardiogenic Differentiation of Cardiac Progenitor Cells

Cardiac progenitor cells (CPCs) are multipotent, self-renewing cells that can regenerate the myocardium and improve cardiac function in animal models of MI by cardiogenic differentiation. However, limited survival of stem/progenitor cells, myocardial scarring and fibrosis inhibit cardiac regeneration. Notch signaling promotes early cardiac development, cardiomyocyte survival and cardiac gene expression in circulating endothelial progenitor cells, mesenchymal stem cells and CPCs. As misregulation of Notch signaling during development is lethal due to cardiovascular defects, activating this critical pathway during cell transplantation could improve the efficacy of stem cell therapy. We investigated whether self-assembling peptide nanofiber hydrogels can be used to activate Notch1 signaling. The 16 amino acid self-assembling scaffold (RAD) was modified with a 20 amino acid peptide mimicking the active site of Notch1 ligand, Jagged1 (RJAG) or with the corresponding scrambled peptide (RSCR). To determine whether scaffold stiffness regulates Notch1 activation, CHO cells with Notch1 responsive YFP expression were cultured in scaffolds of 1-3% w/v in presence of RSCR or RJAG at a 1:10 ligand: scaffold ratio in 3D. Presence of the RJAG peptide (p<0.01) and % concentration of the scaffold (p<0.01) increased Notch1 activation significantly (n=5) indicating that RJAG mediated Notch1 activation in 3D is scaffold stiffness-dependent. Therefore, CPCs were cultured within 3D scaffolds (1-3% w/v; empty, scaffold +RJAG or RSCR) and cardiogenic gene expression was determined by qPCR. An increase in expression of early endothelial (Flk1, Flt1, vWF) and smooth muscle (sm22α, sm αactin) genes was observed in CPCs cultured in 3D scaffolds containing RJAG but not when cultured in 2D. These data show that Notch1 activation is dependent on ligand density and scaffold stiffness. Delivery of CPCs in JAG1 containing self-assembling scaffolds could be used to enhance therapeutic angiogenesis and improve cardiac function following myocardial infarction.

Download Full-text

Abstract 247: Scaffold-stiffness Dependent Notch1 Activation Regulates Cardiogenic Gene Expression In Cardiac Progenitor Cells

Circulation Research ◽

10.1161/res.113.suppl_1.a247 ◽

2013 ◽

Vol 113 (suppl_1) ◽

Author(s):

Archana V Boopathy ◽

Pao L Che ◽

Yoshie Narui ◽

Khalid Salaita ◽

Michael E Davis

Keyword(s):

Gene Expression ◽

Smooth Muscle ◽

Cardiac Function ◽

Progenitor Cells ◽

Adult Stem Cells ◽

Cardiac Progenitor Cells ◽

Critical Pathway ◽

Cardiac Gene Expression ◽

Self Assembling ◽

Cardiac Gene

Rationale: Cardiac progenitor cells (CPCs) are multipotent, self-renewing cells that can regenerate the myocardium and improve cardiac function in animal models of myocardial infarction (MI). However, limited survival of stem/progenitor cells inhibits cardiac regeneration. Force dependent Notch activation promotes cardiac development and cardiac gene expression in many adult stem cells. As dysregulation of Notch signaling leads to embryonic lethal cardiovascular defects, activating this critical pathway during cell transplantation could improve efficacy of stem cell therapy. Objective: Investigate i) whether self-assembling peptide scaffolds can be used to activate Notch1 signaling in CPCs to promote cardiogenic differentiation and ii) the effect of scaffold stiffness on Notch1 activation and differentiation. Methods: Rat CPCs (c-kit + ) were cultured for 48h in 3D self-assembling scaffolds of varying stiffness (1% low, 2% high): empty scaffolds (RADA), scaffolds modified with peptide mimicking Notch1 ligand, Jagged1 (RJAG), or scaffolds modified with a scrambled peptide (RSCR) and cardiogenic gene expression measured by qRT-PCR. CHO cells expressing Notch1 responsive YFP were also cultured in the above scaffolds for 48h and YFP expression was determined. Results are mean ± SEM with p<0.05 considered significant by one or two-way ANOVA with appropriate post test. Results: In the Notch1 reporter cells, Notch1 activation increased significantly in presence of RJAG (p<0.01) and on increasing scaffold stiffness (p<0.01,n=6) indicating scaffold stiffness-dependent Notch1 activation. Culture of CPCs in RJAG containing 1% scaffolds (low stiffness) significantly increased early endothelial and smooth muscle but not cardiac gene expression while in 2% scaffolds (high stiffness) significantly increased only cardiac and not endothelial or smooth muscle gene expression (p<0.05, n≥4). Conclusions: Taken together, these data show that i) Notch1 activation in 3D is dependent on ligand density and scaffold stiffness and ii) stiffness dependent Notch1 activation differentially regulates cardiogenic gene expression in CPCs. Therefore, delivery of CPCs in JAG containing scaffolds could be used to improve cardiac function following MI.

Download Full-text

Abstract 212: Aggregation of Child Cardiac Progenitor Cells into 3D Spheres Improves Endothelial Lineage Commitment

Circulation Research ◽

10.1161/res.119.suppl_1.212 ◽

2016 ◽

Vol 119 (suppl_1) ◽

Author(s):

David Q Trac ◽

Chunhui Xu ◽

Michael E. Davis

Keyword(s):

Stem Cell ◽

Cardiac Function ◽

Notch Signaling ◽

Progenitor Cells ◽

Gene Array ◽

Lineage Commitment ◽

Cardiac Progenitor Cells ◽

Notch Ligand ◽

Monolayer Cultures ◽

Endothelial Lineage

Congenital heart disease is rarely cured by surgery and can lead to life-threatening, intractable right ventricular heart failure (HF). In particular, children with hypoplastic left heart syndrome have a 10 year transplant-free survival rate of 50-75% despite palliative surgical repair. Currently, no effective stem-cell based treatments are available for pediatric HF. Recent stem-cell based clinical trials have been limited by poor differentiation rates and low cell retention. Additionally, we have shown that human cardiac progenitor cells (hCPCs) have reduced regenerative potential as they age, starting as early as 1 year old. We propose the aggregation of CPCs into scaffold-free spheres to improve the differentiation of child CPCs into mature cardiac phenotypes by enhancing intercellular Notch signaling. Notch signaling activity has been implicated in the regulation of CPC fate decisions and prior research in our lab has shown that intramyocardial delivery of Notch-ligand containing hydrogels improves cardiac function. Child CPC spheres were produced at a size of 1500 cells per sphere using a microwell array and cultured in suspension. Using immunohistochemistry, we showed that aggregation of CPCs increased Notch1 expression compared to parallel monolayer cultures. This effect is not limited to CPCs and was recapitulated in spheres of Chinese hamster ovarian cells transfected with Notch1-YFP. Additionally, Notch signaling pathway gene array data showed increased expression of the Notch-cleaving metalloprotease ADAM10 (3.6-fold) and Notch ligand DLL1 (25.0-fold) in CPC spheres by 3 days in culture compared to monolayer cultures. By 14 days in culture, we showed that aggregation of CPCs robustly increases the expression of the GATA4, a cardiac transcription factor associated with angiogenesis, and VEGFR1, an early marker of endothelial lineage commitment. Based on our results, we hypothesize that aggregation of CPCs into spheroids increases endothelial differentiation via a Notch-dependent mechanism. Transplantation of CPC spheres may improve cardiac function in vivo compared to transplantation of single CPCs. The results from our project will facilitate the development of autologous stem-cell based therapies for pediatric HF.

Download Full-text

Implantation of cardiac progenitor cells using self-assembling peptide improves cardiac function after myocardial infarction

Journal of Molecular and Cellular Cardiology ◽

10.1016/j.yjmcc.2010.09.015 ◽

2010 ◽

Vol 49 (6) ◽

pp. 972-983 ◽

Cited By ~ 57

Author(s):

Masakuni Tokunaga ◽

Mei-Lan Liu ◽

Toshio Nagai ◽

Koji Iwanaga ◽

Katsuhisa Matsuura ◽

...

Keyword(s):

Myocardial Infarction ◽

Cardiac Function ◽

Progenitor Cells ◽

Cardiac Progenitor Cells ◽

Self Assembling

Download Full-text

Transcription factor-induced activation of cardiac gene expression in human c-kit+ cardiac progenitor cells

PLoS ONE ◽

10.1371/journal.pone.0174242 ◽

2017 ◽

Vol 12 (3) ◽

pp. e0174242 ◽

Cited By ~ 9

Author(s):

Tareq Al-Maqtari ◽

Kyung U. Hong ◽

Bathri N. Vajravelu ◽

Afsoon Moktar ◽

Pengxiao Cao ◽

...

Keyword(s):

Gene Expression ◽

Transcription Factor ◽

Progenitor Cells ◽

Cardiac Progenitor Cells ◽

Cardiac Gene Expression ◽

Cardiac Gene

Download Full-text

Abstract 300: Pathophysiologically Regulated Gene Expression in Human Stem & Progenitor Cells for Cardiogenic Differentiation and Repair

Circulation ◽

10.1161/circ.118.suppl_18.s_280-b ◽

2008 ◽

Vol 118 (suppl_18) ◽

Author(s):

Zhilin Chen ◽

Sean R Hall ◽

Keith R Brunt ◽

Zhan Liu ◽

David A Ademidun ◽

...

Keyword(s):

Gene Expression ◽

Stem Cells ◽

Stem Cell ◽

Progenitor Cells ◽

Transgene Expression ◽

Starting Point ◽

Inflammatory Stimuli ◽

Regulated Gene Expression ◽

Cardiogenic Differentiation ◽

Therapeutic Genes

Human stem and progenitor cells have emerged as potentially useful substrates for cardiovascular repair through neovascularization and myocardial regeneration. However, efficacy is limited by impedance to stem cell retention, homing and differentiation in hostile microenvironments, as occur in infarcted myocardium. The objective of the current study was to regulate gene function for tailored therapy in post infarct myocardium. Here we show that hypoxic and inflammatory stimuli of the infarct microenvironment regulate a proportional response in gene expression in human endothelial progenitor (EPC) and mesenchymal stem cells (MSC). Highly efficient lentiviral vectors incorporating hypoxia (HRE) and nuclear factor kappa B (NFkB) responsive elements are used to drive transgenes for survival, autologous stem cell homing and cardiogenic differentiation. Utilizing an internal cytomegalovirus promoter deleted lentiviral transfer vector, an HRE-NFkB bicistronic promoter-reporter vector was constructed with a modified internal ribosome entry sequence between green fluorescent protein and luciferase or therapeutic genes. Either hypoxia or inflammation resulted in a seven to ten-fold response of transgene expression assessed by luciferase activity in EPC (hypoxia, 7608±954; inflammation 11492±1384, P<0.01 and P<0.001 vs control 1049±139 respectively, N=6), while combined hypoxic-inflammatory stimuli resulted in a sixty-fold increase of transgene expression (hypoxic-inflammation, 62364±6609, P<0.001 vs control 1049±139, N=6). These results were recapitulated in MSC and with a series of therapeutic genes as determined by transcript, protein expression and activity. Our results demonstrate that regulated vectors provide a proportional response to hostile post-infarct myocardium. Translating cardiovascular regenerative medicine using stem cells requires managing stem cell survival, function and differentiation. Utilizing site-specific pathophysiological cues to auto-regulate reparative and regenerative gene expression, this study is a starting point for sophisticated platforms for patient tailored cell-based cardiogenic therapy.

Download Full-text

Abstract 29: Porcine Decellularized Heart Tissue Enhance the Expression of Contractile Proteins in Human Cardiomyocytes and Differentiated Cardiac Progenitor Cells

Circulation Research ◽

10.1161/res.119.suppl_1.29 ◽

2016 ◽

Vol 119 (suppl_1) ◽

Author(s):

Anne-Cecile Huby ◽

Farideh Beigi ◽

Qian Xiang ◽

Andrea Gobin ◽

Doris Taylor

Keyword(s):

Gene Expression ◽

Progenitor Cells ◽

Ips Cells ◽

Contractile Proteins ◽

Cardiac Cells ◽

Contractile Protein ◽

Cell Phenotype ◽

Cell Physiology ◽

Cardiac Progenitor Cells ◽

Structural Support

Tissue engineering is an evolving tool for repair of cardiovascular damage, in particular after myocardial infarction. Currently, most studies are focused on providing gel or thin synthetic matrices to provide structural support for injured valves, or ventricle. But little is known about how cardiac cells (eg, endothelial cells [ECs], cardiomyocytes [CMs] and cardiac progenitor cells [CPCs]) are modified by an exposure to a scaffold much less how a xenogeneic scaffold may affect cell physiology or function. Our study was designed to examine the effect of rat or pig collagen matrix and decellularized left ventricle extracellular matrix (dECM) tissues on the phenotype of human cardiac cells. Human ECs, CMs and CPCs derived from IPs cells (Cellular Dynamics International) were cultured singly or together on rat or pig collagen matrices or on dECM. Protein and gene expression was investigated by immunohistochemistry, histology and real time PCR. All 3 cell types survived on both types of support when delivered singly or together. Endothelial cell PECAM-1 expression was enhanced on decellularized tissues particularly on rat matrix. Cardiomyocyte contractile protein expression did not differ with support type, whereas CPC contractile protein gene expression increased on both decellularized tissues more so on pig matrix. Additionally, when the cells were co-cultured, single cell type gene expression was modified. Our study showed that human cardiac cells are influenced by the structural support on which they are cultivated. Cardiac ECM enhanced the expression of contractile proteins and endothelial markers but matrix species had minimal influence on this effect. Furthermore, cell co-culture altered gene expression suggesting cell communication is intact on the matrix. This study shows that cell phenotype and behavior is impacted by the tissue matrix to a greater degree than occurs with a simple one protein support and suggests complex decellularized matrix may be superior to successfully engineer cardiac constructs with intact physiology. Additionally, the successful differentiation of IPs cells into cardiomyocytes on decellularized matrix opens avenue to build tissue engineer constructs from patients with heart disease as a screening tool.

Download Full-text

Abstract 212: Hydrogen Peroxide Acutely Stimulates Cardiogenic Gene Expression in Cardiac Progenitor Cells

Circulation Research ◽

10.1161/res.111.suppl_1.a212 ◽

2012 ◽

Vol 111 (suppl_1) ◽

Author(s):

Karl D Pendergrass ◽

Michael E Davis

Keyword(s):

Gene Expression ◽

Heart Failure ◽

Hydrogen Peroxide ◽

Smooth Muscle ◽

Progenitor Cells ◽

Matched Control ◽

Cardiac Progenitor Cells ◽

H2o2 Treatment ◽

Apoptotic Effect ◽

H2o2 Pretreatment

Following acute myocardial infarction, billions of myocytes are lost to cell death. The damage is regional and lost cells are replaced with a collagen scar. One potential therapy to delay or prevent progression into heart failure is regeneration of the damaged myocardium through cell therapy with cardiac progenitor cells (CPC). Reactive oxygen species, specifically hydrogen peroxide, elicit varying responses from different stem/progenitor cells. In the present studies, we sought to determine the effect of acute H2O2 treatment on CPC survival and differentiation. CPCs were isolated and cultured with leukemia inhibitory factor (LIF) to retain their stem-like qualities. CPCs were allowed to differentiate in the absence of LIF for up to 5 days + H2O2. H2O2 (100μM) significantly increased expression of the smooth muscle marker, alpha smooth muscle actin (αSM) by Day 2 as compared to time-matched controls (Ctl: 1.8+1.3 vs 100 μM: 8.5+1.1; p<0.001; N=3). We also observed a trend for an increase in smooth muscle 22 alpha (SM 22α) gene expression by Day 2. Interestingly, by Day 5 the stimulatory effect of 100 μM H2O2 treatment on α SM and SM 22α was reversed and significantly decreased compared to Day 2 (D5: α SM: 0.43+0.05, SM 22α: 0.41+0.2 vs. D2: SM 22α: 10.58+2.3; p<0.01; N=3-4). Evaluation of the endothelial marker VEGFR-2 (Flk-1) showed a trend for an increase in gene expression by Day 2 following 100 μM H2O2 treatment compared to the time-matched control. We also observed an anti-apoptotic effect on CPCs following serum removal, in which 2 days of 100μM H2O2 pretreatment lead to approximately a 55% decrease in cell death compared to untreated CPCs (Ctl: 19.1+2.4 vs 100 μM: 10.5+1.7; p<0.05; N=3-4). The protective effect of the H2O2 pretreatment could be attributed to an increase in anti-oxidative enzymatic capacity in CPCs. There was a trend for an increase in catalase gene expression. In conclusion, our results showed that acute H2O2 preconditioning exerted a stimulatory effect on smooth muscle gene expression and an anti-apoptotic effect compared to time-matched Control CPCs. Furthermore, acute H2O2 preconditioning may aid in directing CPC differentiation towards a vascular phenotype and angiogenesis in the infarcted myocardium, which may prevent or delay heart failure.

Download Full-text