Rejuvenating effects of young extracellular vesicles in aged rats and in cellular models of human senescence.

Rejuvenation of an old organism was achieved in heterochronic parabiosis experiments, implicating different soluble factors in this effect. Extracellular vesicles (EVs) are the secretory effectors of many cells, including cardiosphere-derived cells (CDCs) with demonstrated anti-senescent effect. 1.

Annexin A1-dependent tethering promotes extracellular vesicle aggregation revealed with single-extracellular vesicle analysis.

Extracellular vesicles (EVs) including plasma membrane-derived microvesicles and endosomal-derived exosomes aggregate by unknown mechanisms, forming microcalcifications that promote cardiovascular disease, the leading cause of death worldwide. Here, we show a framework for assessing cell-independent EV mechanisms in disease by suggesting that annexin A1 (ANXA1)-dependent tethering induces EV aggregation and microcalcification. We present single-EV microarray, a method to distinguish microvesicles from exosomes and assess heterogeneity at a single-EV level.

Mechanism of Enhanced MerTK-Dependent Macrophage Efferocytosis by Extracellular Vesicles.

Objective: Extracellular vesicles secreted by cardiosphere-derived cells (CDC) polarize macrophages toward a distinctive phenotype with enhanced phagocytic capacity (M). These changes underlie cardioprotection by CDC and by the parent CDCs, notably attenuating the no-reflow phenomenon following myocardial infarction, but the mechanisms are unclear. Here, we tested the hypothesis that M are especially effective at scavenging debris from dying cells (ie, efferocytosis) to attenuate irreversible damage post-myocardial infarction.

Reverse electrical remodeling in rats with heart failure and preserved ejection fraction.

Sudden death is the most common mode of exodus in patients with heart failure and preserved ejection fraction (HFpEF). Cardiosphere-derived cells (CDCs) reduce inflammation and fibrosis in a rat model of HFpEF, improving diastolic function and prolonging survival. We tested the hypothesis that CDCs decrease ventricular arrhythmias (VAs) and thereby possibly contribute to prolonged survival.

Targeting extracellular vesicles to injured tissue using membrane cloaking and surface display.

Background: Extracellular vesicles (EVs) and exosomes are nano-sized, membrane-bound vesicles shed by most eukaryotic cells studied to date. EVs play key signaling roles in cellular development, cancer metastasis, immune modulation and tissue regeneration. Attempts to modify exosomes to increase their targeting efficiency to specific tissue types are still in their infancy.

Exosomal miR-21a-5p mediates cardioprotection by mesenchymal stem cells.

Though experimental, stem cell transplantation has the potential to improve the condition of the heart after myocardial infarction. It does so by reducing infarct size and inducing repair of heart muscle and its blood supply. Mesenchymal stem cells (MSC) have been found to be effective in pre-clinical animal models and clinical trials, but the mechanisms by which they induce cardioprotection and repair are still not fully understood.

Newt cells secrete extracellular vesicles with therapeutic bioactivity in mammalian cardiomyocytes.

Newts can regenerate amputated limbs and cardiac tissue, unlike mammals which lack broad regenerative capacity. Several signaling pathways involved in cell proliferation, differentiation and survival during newt tissue regeneration have been elucidated, however the factors that coordinate signaling between cells, as well as the conservation of these factors in other animals, are not well defined. Here we report that media conditioned by newt limb explant cells (A1 cells) protect mammalian cardiomyocytes from oxidative stress-induced apoptosis.

Allogeneic head and body reconstruction: mouse model.

Aims: There is still no effective way to save a surviving healthy mind when there is critical organ failure in the body. The next frontier in CTA is allo-head and body reconstruction (AHBR), and just as animal models were key in the development of CTA, they will be crucial in establishing the procedures of AHBR for clinical translation.

Methods And Results: Our approach, pioneered in mice, involves retaining the donor brain stem and transplanting the recipient head.

Azelastine desensitization of transient receptor potential vanilloid 1: a potential mechanism explaining its therapeutic effect in nonallergic rhinitis.

Background: Capsaicin, a prototypic transient receptor potential vanilloid 1 (TRPV1) agonist, has been shown to be more clinically effective in the treatment of nonallergic rhinitis (NAR) compared with other rhinitis subtypes. Azelastine has also been found to be clinically effective in the treatment of NAR but its mechanism(s) of action is still poorly elucidated. This study was designed to determine, using in vitro cell lines, whether topical therapies including azelastine have activity on TRPV1 ion channels similar to capsaicin.

Molecular strategy to reduce in vivo collagen barrier promotes entry of NCX1 positive inducible pluripotent stem cells (iPSC(NCX¹⁺)) into ischemic (or injured) myocardium.

Objective: The purpose of this study was to assess the effect of collagen composition on engraftment of progenitor cells within infarcted myocardium.

Background: We previously reported that intramyocardial penetration of stem/progenitor cells in epicardial patches was enhanced when collagen was reduced in hearts overexpressing adenylyl cyclase-6 (AC6). In this study we hypothesized an alternative strategy wherein overexpression of microRNA-29b (miR-29b), inhibiting mRNAs that encode cardiac fibroblast proteins involved in fibrosis, would similarly facilitate progenitor cell migration into infarcted rat myocardium.

Probenecid as a noninjurious positive inotrope in an ischemic heart disease murine model.

The current therapeutic options for acute decompensated heart failure are limited to afterload reducers and positive inotropes. The latter increases myocardial contractility through changes in myocyte calcium (Ca²⁺) handling (mostly through stimulation of the β-adrenergic pathways [β-ADR]) and is associated with paradoxical effects of arrhythmias, cell death, and subsequently increased mortality. We have previously demonstrated that probenecid can increase cytosolic Ca²⁺ levels in the cardiomyocyte resulting in an improved inotropic response in vitro and in vivo without activating the β-ADR system.

Genetically manipulated progenitor/stem cells restore function to the infarcted heart via the SDF-1α/CXCR4 signaling pathway.

Progenitor/stem cells are a viable option to replace myocytes lost subsequent to myocardial infarction (MI). The stromal cell-derived factor-1α/CXC-chemokine receptor type 4 (SDF-1α/CXCR4) axis plays an important role in numerous biological processes including hematopoiesis, cardiogenesis, vasculogenesis, and neuronal development, as well as endothelial progenitor cell trafficking. The secretion of chemoattractants such as SDF-1α at the site of injury creates an environment facilitating the homing of circulating CXCR4 positive and other stem cells (such as mast/stem cell growth factor receptor kit-positive (c-kit(+)) and c-kit(+)/GATA binding protein 4 positive (GATA4(+)) cells) for organ regeneration and tissue repair.

The stimulation of HSD17B7 expression by estradiol provides a powerful feed-forward mechanism for estradiol biosynthesis in breast cancer cells.

Our laboratory has previously cloned and purified an ovarian protein found to be a novel 17β-hydroxysteroid dehydrogenase type 7 enzyme (HSD17B7) (formerly prolactin receptor-associated protein) that converts the weak estrogen, estrone, to the highly potent estradiol. The regulation of this enzyme has not yet been explored. In this report, we show high expression of HSD17B7 in human ductal carcinoma and breast cancer cell lines and present evidence for a strong up-regulation of this enzyme by estradiol at the level of mRNA, protein expression, and promoter activity in MCF-7 cells.