Prostaglandin E2 Induces YAP1 and Agrin Through EP4 in Neonatally-Derived Islet-1+ Stem Cells.

Prostaglandin E2 (PGE2) has recently gained attention in the field of regenerative medicine because of the beneficial effects of this molecule on stem cell proliferation and migration. Furthermore, PGE2 has the ability to mitigate immune rejection and fibrosis. In the colon and kidney, PGE2 induces YAP1, a transcription factor critical for cardiac regeneration.

Neonatal Cardiovascular-Progenitor-Cell-Derived Extracellular Vesicles Activate YAP1 in Adult Cardiac Progenitor Cells.

New stem cell and extracellular-vesicle-based therapies have the potential to improve outcomes for the increasing number of patients with heart failure. Since neonates have a significantly enhanced regenerative ability, we hypothesized that extracellular vesicles isolated from Islet-1+ expressing neonatal human cardiovascular progenitors (CPCs) will induce transcriptomic changes associated with improved regenerative capability when co-cultured with CPCs derived from adult humans. In order to test this hypothesis, we isolated extracellular vesicles from human neonatal Islet-1+ CPCs, analyzed the extracellular vesicle content using RNAseq, and treated adult CPCs with extracellular vesicles derived from neonatal CPCs to assess their functional effect.

A Biomimetic Approach Utilizing Pulsatile Perfusion Generates Contractile Vascular Grafts.

Surgical implantation of decellularized cadaveric arteries is routinely used to treat right-sided congenital cardiac lesions. These acellular conduits lack the capacity for somatic growth and are prone to stenosis and calcification, necessitating multiple operations throughout childhood. Islet-1+ cardiovascular progenitor cells (CPCs) have demonstrated the capacity for differentiation into all cell types of the heart and outflow tracts.

Identification of SALL4 Expressing Islet-1+ Cardiovascular Progenitor Cell Clones.

The utilization of cardiac progenitor cells (CPCs) has been shown to induce favorable regenerative effects. While there are various populations of endogenous CPCs in the heart, there is no consensus regarding which population is ideal for cell-based regenerative therapy. Early-stage progenitor cells can be differentiated into all cardiovascular lineages, including cardiomyocytes and endothelial cells.

MicroRNA Expression in the Infarcted Heart Following Neonatal Cardiovascular Progenitor Cell Transplantation in a Sheep Model of Stem Cell-Based Repair.

Myocardial infarctions affect approximately 735,000 people annually in the United States and have a substantial impact on quality of life. Neonates have an enhanced capability of repairing cardiovascular damage, while adults do not. The mechanistic basis for this age-dependent difference in regenerative capacity remains unknown.

Biomanufacturing in low Earth orbit for regenerative medicine.

Research in low Earth orbit (LEO) has become more accessible. The 2020 Biomanufacturing in Space Symposium reviewed space-based regenerative medicine research and discussed leveraging LEO to advance biomanufacturing for regenerative medicine applications. The symposium identified areas where financial investments could stimulate advancements overcoming technical barriers.

Long-Term Hypoxia Maintains a State of Dedifferentiation and Enhanced Stemness in Fetal Cardiovascular Progenitor Cells.

Early-stage mammalian embryos survive within a low oxygen tension environment and develop into fully functional, healthy organisms despite this hypoxic stress. This suggests that hypoxia plays a regulative role in fetal development that influences cell mobilization, differentiation, proliferation, and survival. The long-term hypoxic environment is sustained throughout gestation.

The Impact of Spaceflight and Microgravity on the Human Islet-1+ Cardiovascular Progenitor Cell Transcriptome.

Understanding the transcriptomic impact of microgravity and the spaceflight environment is relevant for future missions in space and microgravity-based applications designed to benefit life on Earth. Here, we investigated the transcriptome of adult and neonatal cardiovascular progenitors following culture aboard the International Space Station for 30 days and compared it to the transcriptome of clonally identical cells cultured on Earth. Cardiovascular progenitors acquire a gene expression profile representative of an early-stage, dedifferentiated, stem-like state, regardless of age.

Effects of Spaceflight and Simulated Microgravity on YAP1 Expression in Cardiovascular Progenitors: Implications for Cell-Based Repair.

Spaceflight alters many processes of the human body including cardiac function and cardiac progenitor cell behavior. The mechanism behind these changes remains largely unknown; however, simulated microgravity devices are making it easier for researchers to study the effects of microgravity. To study the changes that take place in cardiac progenitor cells in microgravity environments, adult cardiac progenitor cells were cultured aboard the International Space Station (ISS) as well as on a clinostat and examined for changes in Hippo signaling, a pathway known to regulate cardiac development.

Cardiovascular progenitor cells cultured aboard the International Space Station exhibit altered developmental and functional properties.

The heart and its cellular components are profoundly altered by missions to space and injury on Earth. Further research, however, is needed to characterize and address the molecular substrates of such changes. For this reason, neonatal and adult human cardiovascular progenitor cells (CPCs) were cultured aboard the International Space Station.

Short-term hypoxia improves early cardiac progenitor cell function .

The use of cardiovascular progenitor cells (CPCs) to repair damaged myocardium has been the focus of intense research. Previous reports have shown that pretreatments, including hypoxia, improve cell function. However, the age-dependent effects of short-term hypoxia on CPCs, and the role of signaling in these effects, are unknown.

Spaceflight Activates Protein Kinase C Alpha Signaling and Modifies the Developmental Stage of Human Neonatal Cardiovascular Progenitor Cells.

Spaceflight impacts cardiovascular function in astronauts; however, its impact on cardiac development and the stem cells that form the basis for cardiac repair is unknown. Accordingly, further research is needed to uncover the potential relevance of such changes to human health. Using simulated microgravity (SMG) generated by two-dimensional clinorotation and culture aboard the International Space Station (ISS), we assessed the effects of mechanical unloading on human neonatal cardiovascular progenitor cell (CPC) developmental properties and signaling.

A Hyper-Crosslinked Carbohydrate Polymer Scaffold Facilitates Lineage Commitment and Maintains a Reserve Pool of Proliferating Cardiovascular Progenitors.

Background: Cardiovascular progenitor cells (CPCs) have been cultured on various scaffolds to resolve the challenge of cell retention after transplantation and to improve functional outcome after cell-based cardiac therapy. Previous studies have reported successful culture of fully differentiated cardiomyocytes on scaffolds of various types, and ongoing efforts are focused on optimizing the mix of cardiomyocytes and endothelial cells as well as on the identification of a source of progenitors capable of reversing cardiovascular damage. A scaffold culture that fosters cell differentiation into cardiomyocytes and endothelial cells while maintaining a progenitor reserve would benefit allogeneic cell transplantation.

Clonidine inhibits anti-non-Gal IgM xenoantibody elicited in multiple pig-to-primate models.

Background: Survival of vascularized xenografts is dependent on pre-emptive inhibition of the xenoantibody response against galactosyltransferase knockout (GTKO) porcine organs. Our analysis in multiple GTKO pig-to-primate models of xenotransplantation has demonstrated that the anti-non-gal-α-1,3-gal (anti-non-Gal) xenoantibody response displays limited structural diversity. This allowed our group to identify an experimental compound which selectively inhibited induced anti-non-Gal IgM xenoantibodies.

Simulated Microgravity Exerts an Age-Dependent Effect on the Differentiation of Cardiovascular Progenitors Isolated from the Human Heart.

Microgravity has a profound effect on cardiovascular function, however, little is known about the impact of microgravity on progenitors that reside within the heart. We investigated the effect of simulated microgravity exposure on progenitors isolated from the neonatal and adult human heart by quantifying changes in functional parameters, gene expression and protein levels after 6-7 days of 2D clinorotation. Utilization of neonatal and adult cardiovascular progenitors in ground-based studies has provided novel insight into how microgravity may affect cells differently depending on age.

Rhesus monkeys and baboons develop clotting factor VIII inhibitors in response to porcine endothelial cells or islets.

Background: Xenotransplantation of porcine organs holds promise of solving the human organ donor shortage. The use of α-1,3-galactosyltransferase knockout (GTKO) pig donors mitigates hyperacute rejection, while delayed rejection is currently precipitated by potent immune and hemostatic complications. Previous analysis by our laboratory suggests that clotting factor VIII (FVIII) inhibitors might be elicited by the structurally restricted xenoantibody response which occurs after transplantation of either pig GTKO/hCD55/hCD59/hHT transgenic neonatal islet cell clusters or GTKO endothelial cells.

Xenoantibody response to porcine islet cell transplantation using GTKO, CD55, CD59, and fucosyltransferase multiple transgenic donors.

Background: Promising developments in porcine islet xenotransplantation could resolve the donor pancreas shortage for patients with type 1 diabetes. Using α1,3-galactosyltransferase gene knockout (GTKO) donor pigs with multiple transgenes should extend xenoislet survival via reducing complement activation, thrombus formation, and the requirement for exogenous immune suppression. Studying the xenoantibody response to GTKO/hCD55/hCD59/hHT islets in the pig-to-baboon model, and comparing it with previously analyzed responses, would allow the development of inhibitory reagents capable of targeting conserved idiotypic regions.

Anti-non-Gal-specific combination treatment with an anti-idiotypic Ab and an inhibitory small molecule mitigates the xenoantibody response.

Background: B-cell depletion significantly extends survival of α-1,3-galactosyltranferase knockout (GTKO) porcine organs in pig-to-primate models. Our previous work demonstrated that the anti-non-Gal xenoantibody response is structurally restricted. Selective inhibition of xenoantigen/xenoantibody interactions could prolong xenograft survival while preserving B-cell-mediated immune surveillance.

Endogenous cardiac stem cells for the treatment of heart failure.

Stem cell-based therapies hold promise for regenerating the myocardium after injury. Recent data obtained from phase I clinical trials using endogenous cardiovascular progenitors isolated directly from the heart suggest that cell-based treatment for heart patients using stem cells that reside in the heart provides significant functional benefit and an improvement in patient outcome. Methods to achieve improved engraftment and regeneration may extend this therapeutic benefit.

Efficient generation of integration-free ips cells from human adult peripheral blood using BCL-XL together with Yamanaka factors.

The ability to efficiently generate integration-free induced pluripotent stem cells (iPSCs) from the most readily available source-peripheral blood-has the potential to expedite the advances of iPSC-based therapies. We have successfully generated integration-free iPSCs from cord blood (CB) CD34(+) cells with improved oriP/EBNA1-based episomal vectors (EV) using a strong spleen focus forming virus (SFFV) long terminal repeat (LTR) promoter. Here we show that Yamanaka factors (OCT4, SOX2, MYC, and KLF4)-expressing EV can also reprogram adult peripheral blood mononuclear cells (PBMNCs) into pluripotency, yet at a very low efficiency.

Isolation, Characterization, and Spatial Distribution of Cardiac Progenitor Cells in the Sheep Heart.

Background: Laboratory large animal models are important for establishing the efficacy of stem cell therapies that may be translated into clinical use. The similarity of ovine and human cardiovascular systems provides an opportunity to use the sheep as a large animal model in which to optimize cell-based treatments for the heart. Recent clinical trials in humans using endogenous cardiovascular progenitor cells report significant improvement in cardiac function following stem cell-based therapy.

Genetically Engineered Mesenchymal Stem Cells Influence Gene Expression in Donor Cardiomyocytes and the Recipient Heart.

AIMS: Human embryonic stem cell-derived cardiomyocytes (hESC-CMs) or mesenchymal stem cells (MSCs) facilitate post-infarct recovery, but the potential benefit of combination therapy using MSCs and hESC-CMs has not been examined. Our objective was to define the gene expression changes in donor and host-derived cells that are induced in vivo after co-transplantation of cardiomyocytes with and without mesenchymal stem cells expressing the prosurvival gene heme oxygenase 1. METHODS AND RESULTS: Human MSCs were engineered to over-express heme oxygenase-1 (HO-1) following lentiviral vector-mediated transduction.

Gene transfer of heme oxygenase-1 using an adeno-associated virus serotype 6 vector prolongs cardiac allograft survival.

Introduction. Allograft survival can be prolonged by overexpression of cytoprotective genes such as heme oxygenase-1 (HO-1). Modifications in vector design and delivery have provided new opportunities to safely and effectively administer HO-1 into the heart prior to transplantation to improve long-term graft outcome.