Multipotent fetal-derived Cdx2 cells from placenta regenerate the heart

Discovery of a multipotent cell type from the term human placenta

We report a population of multipotent cells isolated from term human placentas, for the first time, that differentiates into cardiomyocytes and vascular cells with clonal ability, migratory ability, and trancriptomic evidence of immune privilege. Caudal-type homeobox-2 (CDX2) is a conserved factor that regulates trophectoderm formation and placentation during early embryonic development but has not previously been implicated in developmentally conserved regenerative mechanisms. We earlier reported that murine Cdx2 cells restored cardiac function after intravenous delivery in male mice with experimental myocardial infarction (MI). Here we demonstrate that CDX2 cells found in human chorion are poised for cardiovascular differentiation. We isolated CDX2 cells from term placentas of 150 healthy patients and showed that they spontaneously differentiate into cardiomyocytes, functional vascular cells, and retain homing ability in vitro with a transcriptome that supports enhanced cardiogenesis, vasculogenesis, immune modulation, and chemotaxis gene signatures. They restore cardiac function when administered to NOD/SCID mice subjected to MI. CDX2 cells can be clonally propagated in culture with retention of cardiovascular differentiation. Our data compels further use of this ethically feasible cell source in the design of therapeutic strategies for cardiovascular disease.

Presence of fetal microchimerisms in the heart and effect on cardiac repair

Multiple complex biological processes take place during pregnancy, including the migration of fetal cells to maternal circulation and their subsequent engraftment in maternal tissues, where they form microchimerisms. Fetal microchimerisms have been identified in several tissues; nevertheless, their functional role remains largely unknown. Different reports suggest these cells contribute to tissue repair and modulate the immune response, but they have also been associated with pre-eclampsia and tumor formation. In the maternal heart, cells of fetal origin can contribute to different cell lineages after myocardial infarction. However, the functional role of these cells and their effect on cardiac function and repair are unknown. In this work, we found that microchimerisms of fetal origin are present in the maternal circulation and graft in the heart. To determine their functional role, WT female mice were crossed with male mice expressing the diphtheria toxin (DT) receptor. Mothers were treated with DT to eliminate microchimerisms and the response to myocardial infarction was investigated. We found that removal of microchimerisms improved cardiac contraction in postpartum and post-infarction model females compared to untreated mice, where DT administration had no significant effects. These results suggest that microchimerisms play a detrimental role in the mother following myocardial infarction.

Leveraging chromatin state transitions for the identification of regulatory networks orchestrating heart regeneration

The limited regenerative capacity of the human heart contributes to high morbidity and mortality worldwide. In contrast, zebrafish exhibit robust regenerative capacity, providing a powerful model for studying how to overcome intrinsic epigenetic barriers maintaining cardiac homeostasis and initiate regeneration. Here, we present a comprehensive analysis of the histone modifications H3K4me1, H3K4me3, H3K27me3 and H3K27ac during various stages of zebrafish heart regeneration. We found a vast gain of repressive chromatin marks one day after myocardial injury, followed by the acquisition of active chromatin characteristics on day four and a transition to a repressive state on day 14, and identified distinct transcription factor ensembles associated with these events. The rapid transcriptional response involves the engagement of super-enhancers at genes implicated in extracellular matrix reorganization and TOR signaling, while H3K4me3 breadth highly correlates with transcriptional activity and dynamic changes at genes involved in proteolysis, cell cycle activity, and cell differentiation. Using loss- and gain-of-function approaches, we identified transcription factors in cardiomyocytes and endothelial cells influencing cardiomyocyte dedifferentiation or proliferation. Finally, we detected significant evolutionary conservation between regulatory regions that drive zebrafish and neonatal mouse heart regeneration, suggesting that reactivating transcriptional and epigenetic networks converging on these regulatory elements might unlock the regenerative potential of adult human hearts.

Do Fetal Microchimeric Cells Influence Experimental Autoimmune Myocarditis?

Objective: We investigated the presence and influence of fetal microchimerism in the cardiac tissue of mated female mice submitted to experimental autoimmune myocarditis. Materials and methods: Nulliparous BALB/c females and BALB/c females mated with either BALB/c males (syngeneic mating) or C57BL/6 males (allogeneic mating) were immunized with cardiac myosin peptide MyHC-α_614-629 or kept as non-immunized controls. Immunization occurred 6-8 weeks after delivery and mice were assessed after 21 days. Results: Immunized mice of allogeneic mating had a lower production of anti-MyHC-α_614-629 antibodies compared to immunized nulliparous mice. Immunized nulliparous females had an intense mononuclear inflammatory infiltrate in cardiac tissue, associated with fibroplasia, while mated females had a lower inflammatory reaction. An increase in the frequency of microchimeric fetal cells was observed in mice submitted to allogeneic mating following immunization. Conclusion: Allogeneic cells of fetal origin could contribute to mitigating the inflammatory response in experimental myocarditis.

Isoorientin attenuates doxorubicin-induced cardiac injury via the activation of MAPK, Akt, and Caspase-dependent signaling pathways

BACKGROUND

Chemotherapy drugs especially anthracyclines are widely used in the treatment of hematological malignancies and solid tumors. However, their clinical application is limited by dose-dependent and irreversible heart injury, which increases the risk of congestive heart failure and heart-related mortality.

PURPOSE

This study aims to investigate the effect and mechanism of the natural flavonoid isoorientin (ISO) combined with doxorubicin (DOX) on the proliferation of tumor cells and improve the survival rate of DOX-injured cardiomyocytes.

STUDY DESIGN/METHODS

Cardiomyocyte H9c2 and a variety of tumor cells were used to evaluate the protective effect of ISO on DOX-induced myocardial injury and enhance the anticancer effects of DOX. DOX chemotherapy-injured mice were used to evaluate the cardioprotective effect of ISO.

RESULTS

The antiproliferation of DOX on Hela, HepG2, HT-29, and A549 cells could be increased synergistically when cotreated with ISO in vitro. ISO could also improve the survival rate of DOX-injured cardiomyocytes by reducing reactive oxygen species, maintaining mitochondrial function, and inhibiting apoptosis. In mice receiving DOX, a protective effect on myocardial tissue, which was reflected by improved survival state of mice receiving chemotherapy, was observed. The ECG, myocardial zymogram data, HE staining, and TEM observation of myocardial tissue sections showed that ISO had a dose-dependent protective effect on the mouse hearts injured by DOX. Network pharmacology and cardiomyocyte proteomics were used to seek for related target proteins to reveal the protective mechanism of ISO on mouse models, and some potential targets (including caspase-3, EGFR, MAPK1, ESR1, CDC42, STAT1, JAK2, LCK, and CDK2) were generated. Western blotting was further used to verify that ISO upregulated Nrf2 and TGF-β3 by downregulating the phosphorylation levels of JNK and p38 proteins on the MAPK pathway and the Akt and Stat3 expression levels. The downregulation of cleaved caspase-3 and upregulation of Bcl-xl by ISO further confirmed its inhibition on caspase-dependent cardiomyocyte apoptosis.

CONCLUSION

ISO could be a potential synergistic anticancer agent with a favorable property of reducing the cardiotoxicity for DOX, and the effect mechanism could refer to the inhibition of ISO on MAPK and caspase-dependent apoptosis pathways.

Fetomaternal microchimerism in tissue repair and tumor development

In various placental mammals, the bidirectional exchange of cells during pregnancy can lead to the acquisition of genetically unique cells that can persist in both mother and child for decades. Over the years, it has become increasingly clear that this phenomenon, termed fetomaternal microchimerism may play key roles in a number of biological processes. In this perspective, we explore the concept of fetomaternal microchimerism and outline how fetal microchimeric cells are detected and immunologically tolerated within the maternal setting. Moreover, we discuss undertakings in the field that hint at the significant plasticity of fetal microchimeric cells and their potential roles in promoting maternal wound healing. Finally, we explore the multifaceted roles of fetal microchimeric cells in cancer development and progression. A deeper understanding of fetomaternal chimerism in healthy and diseased states will be key toward developing more efficient anti-cancer treatments and regenerative therapies.

Functional antagonism between ΔNp63α and GCM1 regulates human trophoblast stemness and differentiation

The combination of EGF, CHIR99021, A83-01, SB431542, VPA, and Y27632 (EGF/CASVY) facilitates the derivation of trophoblast stem (TS) cells from human blastocysts and first-trimester, but not term, cytotrophoblasts. The mechanism underlying this chemical induction of TS cells remains elusive. Here we demonstrate that the induction efficiency of cytotrophoblast is determined by functional antagonism of the placental transcription factor GCM1 and the stemness regulator ΔNp63α. ΔNp63α reduces GCM1 transcriptional activity, whereas GCM1 inhibits ΔNp63α oligomerization and autoregulation. EGF/CASVY cocktail activates ΔNp63α, thereby partially inhibiting GCM1 activity and reverting term cytotrophoblasts into stem cells. By applying hypoxia condition, we can further reduce GCM1 activity and successfully induce term cytotrophoblasts into TS cells. Consequently, we identify mitochondrial creatine kinase 1 (CKMT1) as a key GCM1 target crucial for syncytiotrophoblast differentiation and reveal decreased CKMT1 expression in preeclampsia. Our study delineates the molecular underpinnings of trophoblast stemness and differentiation and an efficient method to establish TS cells from term placentas.

Trophoblast stem cells can be derived from human blastocysts and first-trimester, but not term, cytotrophoblasts. Here the authors show that induction efficiency of cytotrophoblast is determined by antagonism between GCM1 and ΔNp63α and manipulating this antagonism facilitates derivation of TS cells from term placenta.

Side-Population Trophoblasts Exhibit the Differentiation Potential of a Trophoblast Stem Cell Population, Persist to Term, and are Reduced in Fetal Growth Restriction

BACKGROUND

Fetal growth restriction often results from poor placental function and is a major cause of stillbirth. Clinically, fetal growth restriction is difficult to diagnose and currently has no effective treatment. Trophoblasts are unique placental cells that form the feto-maternal interface and facilitate nutrient and gas exchange. Fetal growth restriction is linked to inadequate trophoblast function. However, our understanding of the mechanisms underlying this dysfunction are poor, in part because of our inability to isolate and study the trophoblast stem cells from which mature trophoblasts arise in pathologic pregnancies.

METHODS

Cells isolated from first-trimester placentae using the Hoechst side-population technique were propagated or differentiated into mature trophoblasts. Side-population trophoblasts were isolated from normal third-trimester and growth restricted placentae using the same technique. First and third-trimester side-population trophoblasts were compared by microarray analysis.

RESULTS

First-trimester side-population trophoblasts could be propagated in an undifferentiated state or differentiated, via intermediate cytotrophoblasts, into syncytiotrophoblast or extravillous trophoblasts. Using the same technique, side-population trophoblasts could be isolated from term placentae for the first time, demonstrating that while they were present at consistent levels throughout gestation (~3·5%), side-population trophoblasts were significantly depleted in growth restricted pregnancies (0·32%).

CONCLUSIONS

Our novel method of isolating a population of human trophoblast stem cell-like cells directly from human placental tissue throughout gestation provides the first insights into trophoblast dysfunction in pregnancy pathologies. The depletion of side-population trophoblasts in growth restricted placentae may contribute to poor placental function.

Regulation of maternal-fetal metabolic communication

Pregnancy may be the most nutritionally sensitive stage in the life cycle, and improved metabolic health during gestation and early postnatal life can reduce the risk of chronic disease in adulthood. Successful pregnancy requires coordinated metabolic, hormonal, and immunological communication. In this review, maternal-fetal metabolic communication is defined as the bidirectional communication of nutritional status and metabolic demand by various modes including circulating metabolites, endocrine molecules, and other secreted factors. Emphasis is placed on metabolites as a means of maternal-fetal communication by synthesizing findings from studies in humans, non-human primates, domestic animals, rabbits, and rodents. In this review, fetal, placental, and maternal metabolic adaptations are discussed in turn. (1) Fetal macronutrient needs are summarized in terms of the physiological adaptations in place to ensure their proper allocation. (2) Placental metabolite transport and maternal physiological adaptations during gestation, including changes in energy budget, are also discussed. (3) Maternal nutrient limitation and metabolic disorders of pregnancy serve as case studies of the dynamic nature of maternal-fetal metabolic communication. The review concludes with a summary of recent research efforts to identify metabolites, endocrine molecules, and other secreted factors that mediate this communication, with particular emphasis on serum/plasma metabolomics in humans, non-human primates, and rodents. A better understanding of maternal-fetal metabolic communication in health and disease may reveal novel biomarkers and therapeutic targets for metabolic disorders of pregnancy.

Clinical-based Cell Therapies for Heart Disease-Current and Future State

Patients have an ongoing unmet need for effective therapies that reverse the cellular and functional damage associated with heart damage and disease. The discovery that ~1%-2% of adult cardiomyocytes turn over per year provided the impetus for treatments that stimulate endogenous repair mechanisms that augment this rate. Preclinical and clinical studies provide evidence that cell-based therapy meets these therapeutic criteria. Recent and ongoing studies are focused on determining which cell type(s) works best for specific patient population(s) and the mechanism(s) by which these cells promote repair. Here we review clinical and preclinical stem cell studies and anticipate future directions of regenerative medicine for heart disease.

Cardiopoietic stem cell therapy restores infarction-altered cardiac proteome

Cardiopoietic stem cells have reached advanced clinical testing for ischemic heart failure. To profile their molecular influence on recipient hearts, systems proteomics was here applied in a chronic model of infarction randomized with and without human cardiopoietic stem cell treatment. Multidimensional label-free tandem mass spectrometry resolved and quantified 3987 proteins constituting the cardiac proteome. Infarction altered 450 proteins, reduced to 283 by stem cell treatment. Notably, cell therapy non-stochastically reversed a majority of infarction-provoked changes, remediating 85% of disease-affected protein clusters. Pathway and network analysis decoded functional reorganization, distinguished by prioritization of vasculogenesis, cardiac development, organ regeneration, and differentiation. Subproteome restoration nullified adverse ischemic effects, validated by echo-/electro-cardiographic documentation of improved cardiac chamber size, reduced QT prolongation and augmented ejection fraction post-cell therapy. Collectively, cardiopoietic stem cell intervention transitioned infarcted hearts from a cardiomyopathic trajectory towards pre-disease. Systems proteomics thus offers utility to delineate and interpret complex molecular regenerative outcomes.

Multipotency of mouse trophoblast stem cells

BACKGROUND

In a number of disease processes, the body is unable to repair injured tissue, promoting the need to develop strategies for tissue repair and regeneration, including the use of cellular therapeutics. Trophoblast stem cells (TSCs) are considered putative stem cells as they differentiate into other subtypes of trophoblast cells. To identify cells for future therapeutic strategies, we investigated whether TSCs have properties of stem/progenitor cells including self-renewal and the capacity to differentiate into parenchymal cells of fetal organs, in vitro and in vivo.

METHODS

TSCs were isolated using anti-CD117 micro-beads, from embryonic day 18.5 placentas. In vitro, CD117+ TSCs were cultured, at a limiting dilution in growth medium for the development of multicellular clones and in specialized medium for differentiation into lung epithelial cells, cardiomyocytes, and retinal photoreceptor cells. CD117+ TSCs were also injected in utero into lung, heart, and the sub-retinal space of embryonic day 13.5 fetuses, and the organs were harvested for histological assessment after a natural delivery.

RESULTS

We first identified CD117+ cells within the labyrinth zone and chorionic basal plate of murine placentas in late pregnancy, embryonic day 18.5. CD117+ TSCs formed multicellular clones that remained positive for CD117 in vitro, consistent with self-renewal properties. The clonal cells demonstrated multipotency, capable of differentiating into lung epithelial cells (endoderm), cardiomyocytes (mesoderm), and retinal photoreceptor cells (ectoderm). Finally, injection of CD117+ TSCs in utero into lungs, hearts, and the sub-retinal spaces of fetuses resulted in their engraftment on day 1 after birth, and the CD117+ TSCs differentiated into lung alveolar epithelial cells, heart cardiomyocytes, and retina photoreceptor cells, corresponding with the organs in which they were injected.

CONCLUSIONS

Our findings demonstrate that CD117+ TSCs have the properties of stem cells including clonogenicity, self-renewal, and multipotency. In utero administration of CD117+ TSCs engraft and differentiate into resident cells of the lung, heart, and retina during mouse development.

Recent advances in myocardial regeneration strategy

This review described the current status of research into the regeneration potential of myocardial cells after myocardial injury, focussing on possible mechanisms of regeneration and the application of animal models to human biology, all with the aim of evaluating any novel approaches to the regeneration of human cardiomyocytes. A literature review was undertaken of the PubMed® and The Cochrane Library databases using the search terms ‘regeneration’, ‘heart regeneration’, ‘cardiac regeneration’, ‘proliferation’, ‘animal model’, ‘repair’ and ‘myocardial cell injury’ in English language publications only. The search covered publications between 1 January 2002 to 31 December 2017. The cardiac regeneration capability significantly differed among different species. In lower vertebrates, such as zebrafish, cardiomyocytes possess a sustained regeneration capacity under specific conditions. In mammalian animals, such as mice, the cardiomyocytes retain a regeneration capability under specific conditions, which gradually declines. Inflammation, non-coding RNA, gene regulatory elements, signal transduction and cell phenotype transformation play pivotal roles in cardiomyocyte regeneration. Myocardial regeneration appears to be a viable repair strategy for cardiomyocyte loss, which deserves further research in order to validate its clinical applicability in humans.