Posts in Category: Stem Cells & Regenerative Medicine

Endocardial Cell Plasticity in Cardiac Development, Diseases and Regeneration

Endocardial Cell Plasticity in Cardiac Development, Diseases and Regeneration

Hui Zhang, Kathy O. Lui, Bin Zhou

Mural cells derived from endocardium in developing heart. A and B, Endocardial cells undergo endothelial to mesenchymal transition to form PDGFRβ+PDGFRα+NG2– mesenchymal cells in the cardiac cushion (black arrows). C and D, Mesenchymal cells migrate into myocardium (white arrows) to form PDGFRβ+PDGFRα–NG2+αSMA+ smooth muscle cells or PDGFRβ+PDGFRα–NG2+αSMA– pericytes. [Powerpoint File]

Endocardial Cell Plasticity in Cardiac Development, Diseases and Regeneration

Endocardial Cell Plasticity in Cardiac Development, Diseases and Regeneration

Hui Zhang, Kathy O. Lui, Bin Zhou

Molecular regulation of endocardial cushion endothelial to mesenchymal transition (EndoMT). Multiple signaling pathways including BMP (bone morphogenetic protein), TGFβ (transforming growth factor-β), and Notch control endocardial contribution to cushion morphogenesis through regulating EndoMT. AVC indicates atrioventricular canal; Msx, msh homeobox; OFT, outflow tract; Rbpj, recombination signal binding protein for immunoglobulin kappa J region; Slug, snail family zinc finger 2; Snail, snail family zinc finger 1; and Twist, twist basic helix–loop–helix transcription factor. [Powerpoint File]

Endocardial Cell Plasticity in Cardiac Development, Diseases and Regeneration

Endocardial Cell Plasticity in Cardiac Development, Diseases and Regeneration

Hui Zhang, Kathy O. Lui, Bin Zhou

Schematic showing the endocardial cell plasticity. Endocardial cell (in the center) differentiates into hematopoietic cell, cushion mesenchyme, coronary, liver vascular endothelial cell, and cardiomyocyte (arrows). Question (?) indicates that the cardiomyocyte fate needs validated. Endocardial cell also contributes to fibroblast, adipocyte, pericyte, and smooth muscle cell (dotted arrows), which might be through intermediate stage of mesenchymal cell. [Powerpoint File]

Elixir of Life: Thwarting Aging With Regenerative Reprogramming

Elixir of Life: Thwarting Aging With Regenerative Reprogramming

Ergin Beyret, Paloma Martinez Redondo, Aida Platero Luengo, Juan Carlos Izpisua Belmonte

Regenerative reprogramming approaches. In vivo induction of transdifferentiation can be used to repopulate the cells lost during aging as an alternative to transplantation, complementing the intrinsic regenerative capacity. For instance, neurons lost to neurodegenerative diseases can be replaced by transdifferentiating resident glia or astrocytes; cardiac fibroblasts can be the cell source for induced cardiomyocytes; α, ductal, and acinar cells can be used for β cells. Alternatively, transient 4F (OCT4, KLF4, SOX2, and c-Myc) expression can be used to rejuvenate cells. This in turn can decelerate degeneration of biological units that have low regeneration capacity (eg, aorta) or augment regeneration capacity by counteracting stem cell exhaustion (eg, muscle) or by enhancing the plasticity of organs that intrinsically undergo cell conversions during regeneration (eg, transdifferentiation in the pancreas and dedifferentiation in the kidney). MuSC indicates muscle stem cell. [Powerpoint File]

Physiologic, Pathologic, and Therapeutic Paracrine Modulation of Cardiac Excitation-Contraction Coupling

Physiologic, Pathologic, and Therapeutic Paracrine Modulation of Cardiac Excitation-Contraction Coupling

Joshua Mayourian, Delaine K. Ceholski, David M. Gonzalez, Timothy J. Cashman, Susmita Sahoo, Roger J. Hajjar, Kevin D. Costa

Endothelial–cardiomyocyte interplay through paracrine factors. Endothelial cell NO increases basal contractility via nitrosylation of L-type Ca2+ channel (LTCC) and ryanodine receptor (RyR2). NO attenuates β-adrenergic effects on cardiomyocyte excitation–contraction coupling via cGMP-dependent degradation of cAMP and protein kinase G (PKG)-mediated decrease of LTCC activity. PKG also phosphorylates troponin I, leading to myofilament calcium desensitization and thus increased lusitropy. Endothelin-1, which mainly acts through the endothelin A (ETA) receptor in ventricular cardiomyocytes, may increase calcium entry via protein kinase C (PKC)-mediated (1) increase of LTCC activity, (2) indirect activation of sodium–calcium exchanger (NCX) reverse mode by increasing Na+–H+ exchanger activity, and (3) direct activation of NCX reverse (shown) and forward (not shown) mode. Endothelin-1 alters myofilament Ca2+ sensitivity via protein kinase C/D (PKC/D) phosphorylation of troponin I and myosin-binding protein C. Finally, endothelin-1 may increase calcium-induced calcium release via inositol trisphosphate (IP3) activation of inositol trisphosphate receptor (IP3R), which sensitizes RyR2 on the sarcoplasmic reticulum (SR). Green and red arrows denote activation and inhibition, respectively. PLB indicates phospholamban; and SERCA, sarcoendoplasmic reticulum Ca2+-ATPase. [Powerpoint File]

Physiologic, Pathologic, and Therapeutic Paracrine Modulation of Cardiac Excitation-Contraction Coupling

Physiologic, Pathologic, and Therapeutic Paracrine Modulation of Cardiac Excitation-Contraction Coupling

Joshua Mayourian, Delaine K. Ceholski, David M. Gonzalez, Timothy J. Cashman, Susmita Sahoo, Roger J. Hajjar, Kevin D. Costa

Human engineered cardiac tissue (hECT) contractility assay. A, hECTs are created, cultured, and tested in a custom bioreactor with integrated force-sensing end-posts; as the tissue beats, deflections of the end-posts are tracked. Output contractile metrics include, but are not limited to, developed force (DF), maximum rates of contraction and relaxation (+/− dF/dt, respectively), and beat rate. B, Confocal microscopy of hECTs labeled with cardiac troponin I (green) and DAPI (4’,6-diamidino-2-phenylindole; blue) displays cardiomyocytes with striated sarcomeres and regions of aligned myofibrils. Inset shows magnified view of registered sarcomeres. C, hECT labeled with sarcoendoplasmic reticulum Ca2+-ATPase 2 (red) and DAPI (blue) shows sarcoplasmic reticulum structures distributed throughout the tissue. Bar = 40 µm. [Powerpoint File]

Translational Research in Cardiovascular Repair: A Call for a Paradigm Shift

Translational Research in Cardiovascular Repair: A Call for a Paradigm Shift

Steven A.J. Chamuleau, Mira van der Naald, Andreu M. Climent, Adriaan O. Kraaijeveld, Kim E. Wever, Dirk J. Duncker, Francisco Fernández-Avilés, Roberto Bolli
and on behalf of the Transnational Alliance for Regenerative Therapies in Cardiovascular Syndromes (TACTICS) Group

Translational axis, with stage I studies (including in vitro studies and zebrafish models) to investigate basic mechanisms and discover new proteins and pathways; stage II studies (exploratory studies), predominantly in mouse models, to conduct hypothesis-generating research and initial in vivo testing; and stage III studies (confirmatory studies), as the last step before entering the clinical arena, involving rigorous research in a multicentre setting, with prospective registration of the key features of the study. Preclinical meta-analyses are performed with data from both exploratory and confirmatory studies, with the goal of giving an overview of available data, pointing out the gaps, and providing a guideline for future preclinical research. The level of standardization of methodology increases through the translational axis. [Powerpoint File]

Induced Pluripotent Stem Cells 10 Years Later For Cardiac Applications

Induced Pluripotent Stem Cells 10 Years Later: For Cardiac Applications

Yoshinori Yoshida, Shinya Yamanaka

Factors which possibly cause clonal differences of induced pluripotent stem cells (iPSCs). [Powerpoint File]

Induced Pluripotent Stem Cells 10 Years Later: For Cardiac Applications

Induced Pluripotent Stem Cells 10 Years Later: For Cardiac Applications

Yoshinori Yoshida, Shinya Yamanaka

Patient stratification based on drug responsiveness using induced pluripotent stem cells–derived cardiac myocytes. [Powerpoint File]

Engineering Cardiac Muscle Tissue: A Maturating Field of Research

Engineering Cardiac Muscle Tissue: A Maturating Field of Research

Florian Weinberger, Ingra Mannhardt, Thomas Eschenhagen

Histological structure of native mouse and rat heart (longitudinal mouse heart in A; cross section of rat heart in B), engineered heart tissue (EHT) from neonatal rat heart cells (longitudinal in C, E, cross section in D), or human pluripotent stem cell–derived cardiomyocytes (F–J). A, staining of actinin (green). B, Staining of sarcolemma with wheat germ agglutinin (white in B). C and D, Staining of actinin (red in C and I), F-actin (green in D and J), or actinin and troponin T (green/red in H) and nuclei in blue (all). E, Hematoxylin and eosin–stained paraffin section. A, Reprinted from Mearini et al135 with permission of the publisher. Copyright © 2014, Macmillan Publishers Limited. B, Reprinted from Bensley et al136 with permission. Copyright © 2016, The Authors. C, D, I, and J, Reprinted from Jackman et al35 with permission of the publisher. Copyright © 2016, Elsevier; and from Eschenhagen et al134 (E) with permission of the publisher. Copyright © 2012, the American Physiological Society. F, Reprinted from Hirt et al36 with permission of the publisher. Copyright © 2014, Elsevier. G, Reprinted from Mannhardt et al78 with permission. Copyright © 2016, The Authors. H, Riegler et al93 with permission of the publisher. Copyright © 2015, American Heart Association. [Powerpoint File]

Engineering Cardiac Muscle Tissue: A Maturating Field of Research

Engineering Cardiac Muscle Tissue: A Maturating Field of Research

Florian Weinberger, Ingra Mannhardt, Thomas Eschenhagen

Plane engineered heart tissue (EHT) on Velcro-covered rods (Eschenhagen et al2, A), ring EHTs (Zimmermann et al24, B), fibrin-based mini-EHT on PDMS (polydimethylsiloxane) racks (Hansen et al25, C), cardiac micro tissues (CMT) on fluorescent pillars (Boudou et al34, D), cardiobundles on PDMS frame (Jackman et al35, Copyright © 2016, Elsevier; E), micro heart muscle (Huebsch et al81, Copyright © 2016, The Authors; F), cardiac biowires (Nunes et al131, Copyright © 2013, Nature Publishing Group; G), cardiac patch (Bian et al133, H). Please note that scale bars are only representative, and sketches might not match the exact dimensions. Graphics in A, B, and D were modified from Eschenhagen et al134 with permission of the publisher. Copyright © 2012, the American Physiological Society. [Powerpoint File]

Cell Therapy Trials in Congenital Heart Disease

Cell Therapy Trials in Congenital Heart Disease

Hidemasa Oh

Preclinical study of intracoronary cardiosphere-derived cell (CDC) infusion in a rat model of right heart failure. A–K, Pulmonary artery (PA) banding was created to induce pressure overload right heart failure in rats (weighing 250–300 g). The left thorax was opened to expose the pulmonary artery. A silk suture was tied tightly around an 18-gauge needle alongside the pulmonary artery, followed by a rapid removal of the needle to leave the pulmonary artery constricted in the lumen equal to the diameter of the needle. Intracoronary infusion was performed 4 weeks after pulmonary artery banding. The ascending aorta and the pulmonary artery were occluded with a snare twice for a 20-s interval, 10 min apart, during which time rats received an infusion of CDCs or vehicle into the aortic root directly. Animals were euthanized at 4 weeks after treatment to obtain immuno-histological data. Masson-trichrome staining and hematoxylin and eosin (H&E) staining are shown. One month after pulmonary artery banding, significant right ventricular hypertrophy and fibrosis were observed. Note that CDC treatment reduced cardiac fibrosis, but not hypertrophy, one month after infusion (F and I). Bars, 2 mm in A to C; 20 μm in D to I. J, Animals were separated into 4 groups: (1) sham-operated animals (n=12), (2) rats subjected to pulmonary artery banding for 4 weeks with vehicle treatment (n=12), and (3 and 4) rats subjected to banding for 4 weeks with 2 doses of CDC infusion (0.5×105 or 1×105 cells: n=12 in each). Cardiac fibrosis induced by right ventricle pressure overload was measured. CDC infusion significantly reduced the fibrotic area in a cell dose-dependent manner. K, CDC treatment did not affect the diameter of myocytes, which are mechanically enlarged by pressure overload. L, Rat CDCs were infected by lentiviral vectors harboring human cytomegalovirus promoter-driven LacZ reporter gene and were subjected to intracoronary transfer into rats 4 weeks after pulmonary artery banding. Clear CDC engraftment could be detected along the endocardium and surrounding capillary vessels where the cells had been injected. M, Cardiomyocytes were stained with α-sarcomeric actin (red). Newly regenerated LacZ-positive cardiac muscle cells could be detected by β-galactosidase staining (green). Substantial cardiomyocyte regeneration was verified 4 weeks after CDC delivery. Bars, 50 μm. N, Engrafted LacZ-positive CDCs were evaluated by X-gal staining and corrected by the number of total nuclei appreciated within the respective area. Fibrotic and nonfibrotic areas were determined by Masson-trichrome staining derived from serial sections. O, Differentiated cardiomyocytes after CDC infusion were verified by the cells coexpressing both α-sarcomeric actin (red) and β-galactosidase (LacZ, green). The frequency of the cells coexpressing α-sarcomeric actin among the β-galactosidase–positive cells is shown. Data are expressed as the means (SD). [Powerpoint File]

Heart Failure in Pediatric Patients With Congenital Heart Disease

Heart Failure in Pediatric Patients With Congenital Heart Disease

Robert B. Hinton, Stephanie M. Ware

Genes causing congenital heart disease (CHD) and cardiomyopathy form a complex network. The network diagrams were generated using ToppCluster (www.toppcluster.cchmc.org) software. Gene lists were derived from clinically available next-generation sequencing panels for cardiomyopathy genes (n=50) and CHD genes (n=44). A, Abstracted cluster network showing a selected subset of features from the following categories: Gene ontology (GO): molecular function; GO: biological processes; GO: cellular component; human phenotype; mouse phenotype; pathway; disease (cardiomyopathy and CHD). The features are color coded by category and connected to cardiomyopathy (white circle) and CHD gene nodes. B, Gene level network with nodes (blue) selected from features in GO: biological processes category. The network illustrates that regulation of cellular component of movement, actin filament-based processes, and cardiac chamber morphogenesis are shared in common between cardiomyopathy and CHD genes, whereas regulation of force of heart contraction and tube development are unshared. [Powerpoint File]

Cardiac Regeneration: Lessons From Development

 

Cardiac Regeneration: Lessons From Development

Francisco X. Galdos, Yuxuan Guo, Sharon L. Paige, Nathan J. VanDusen, Sean M. Wu, William T. Pu

Model of the trabeculation process. During trabeulation, a small fraction of cardiomyocytes (CMs) in the compact myocardium (pink) are first specified as trabeculating CMs (brown). These cells delaminate from the compact myocardium and migrate inward to form the first trabecular CMs. CMs in both compacted and trabecular myocardium further proliferate. This proliferation, together with CM migration and rearrangement, results in protrusion and expansion of the trabecular myocardium (illustration credit: Ben Smith). [Powerpoint File]

Cardiac Regeneration: Lessons From Development

Cardiac Regeneration: Lessons From Development

Francisco X. Galdos, Yuxuan Guo, Sharon L. Paige, Nathan J. VanDusen, Sean M. Wu, William T. Pu

Regulation of cardiac progenitor proliferation and differentiation. A, Schematic showing the anterolateral position of first heart field (FHF) progenitors and dorsomedial position of second heart field (SHF) progenitors at embryonic day (E) 7.5. Canonical wingless-type MMTV integration site family member (WNTs), Sonic Hedgehog (SHH), and fibroblast growth factors (FGFs) are expressed dorsally in the region encompassed by the SHF, whereas noncanonical WNTs, BMP2, and FGF8 are expressed ventrally, where the FHF is present. FHF progenitors make up the cardiac crescent and differentiate before the SHF to form the developing heart tube at E8.0. SHF maintains their proliferative state and elongate the heart tube by migrating and differentiating at the inflow and outflow poles of the heart. B, Noncanonical WNTs, BMP2/4, and FGF8 signaling drives FHF progenitors to differentiates toward the myocyte lineage. Meanwhile, canonical WNT/β-catenin, SHH, and FGFs maintain SHF progenitor proliferation. SHF progenitor migration to the outflow and inflow poles of the heart tube exposes them to BMP2/4 and noncanonical WNTs, which drives SHF progenitors to exit their proliferative state and differentiate. C, Canonical WNT/ β-catenin signaling inhibits the differentiation of cardiac progenitors to the myocytes. BMP signaling activates SMAD4 that binds to the transcription factor HOPX to directly inhibit canonical WNT/β-catenin. Moreover, noncanonical WNTs such as WNT5a and WNT11 also inhibit canonical WNT/β-catenin to drive cardiac progenitor differentiation (illustration credit: Ben Smith). [Powerpoint File]