gw-4869 and Myocardial-Infarction

Exosomes released into the plasma after brief cardiac ischaemia mediate subsequent cardioprotection. Whether donor exosomes can provide cardioprotection to recipients with chronic heart failure, which confers the highest perioperative risk, is unknown. We examined whether ischaemic preconditioning (IPC)-induced plasma exosomes exerted cardioprotection after their transfer from normal donors to post-infarcted failing hearts.. Plasma exosomes were obtained from adult rats after IPC or sham. An exosome inhibitor GW4869 was administrated before IPC in an in vivo model of ischaemia/reperfusion (I/R) injury in normal rats. The IPC exosomes or control exosomes from normal donor rats were perfused to the normal or post-infarcted failing rat hearts before ischaemia in Langendorff perfusion experiments. Infarct size, cardiac enzymes, cardiac function, and pro-survival kinases were quantified.. The IPC stimulus increased the release of exosomes, whereas GW4869 inhibited the rise of plasma exosomes. Pre-treatment with GW4869 reversed IPC-mediated cardioprotection against in vivo I/R injury. In the Langendorff perfusion experiments, IPC exosomes from normal donor rats reduced mean infarct size from 41.05 (1.87)% to 31.43 (1.81)% and decreased lactate dehydrogenase activity in the post-infarcted failing rat hearts. IPC exosomes but not control exosomes activated pro-survival kinases in the heart tissues.. Ischaemic preconditioning-induced exosomes from normal rats can restore cardioprotection in heart failure after myocardial infarction, which is associated with activation of pro-survival protein kinases. These results suggest a potential perioperative therapeutic role for ischaemic preconditioning-induced exosomes.

Topics: Animals; Exosomes; Heart; Heart Failure; Ischemic Preconditioning, Myocardial; Myocardial Infarction; Myocardial Reperfusion Injury; Myocardium; Rats

To investigate the involvement of endothelial cells (ECs)-derived exosomes in the anti-apoptotic effect of Danhong Injection (DHI) and the mechanism of DHI-induced exosomal protection against postinfarction myocardial apoptosis.. A mouse permanent myocardial infarction (MI) model was established, followed by a 14-day daily treatment with DHI, DHI plus GW4869 (an exosomal inhibitor), or saline. Phosphate-buffered saline (PBS)-induced ECs-derived exosomes were isolated, analyzed by miRNA microarray and validated by droplet digital polymerase chain reaction (ddPCR). The exosomes induced by DHI (DHI-exo), PBS (PBS-exo), or DHI+GW4869 (GW-exo) were isolated and injected into the peri-infarct zone following MI. The protective effects of DHI and DHI-exo on MI hearts were measured by echocardiography, Masson's trichrome staining, and TUNEL apoptosis assay. The Western blotting and quantitative reverse transcription PCR (qRT-PCR) were used to evaluate the expression levels of miR-125b/p53-mediated pathway components, including miR-125b, p53, Bak, Bax, and caspase-3 activities.. DHI significantly improved cardiac function and reduced infarct size in MI mice (P<0.01), which was abolished by the GW4869 intervention. DHI promoted the exosomal secretion in ECs (P<0.01). According to the results of exosomal miRNA microarray assay, 30 differentially expressed miRNAs in the DHI-exo were identified (28 up-regulated miRNAs and 2 down-regulated miRNAs). Among them, DHI significantly elevated miR-125b level in DHI-exo and DHI-treated ECs, a recognized apoptotic inhibitor impeding p53 signaling (P<0.05). Remarkably, treatment with DHI and DHI-exo attenuated apoptosis, elevated miR-125b expression level, inhibited capsase-3 activity, and down-regulated the expression levels of proapoptotic effectors (p53, Bak, and Bax) in post-MI hearts, whereas these effects were blocked by GW4869 (P<0.05 or P<0.01).. DHI and DHI-induced exosomes inhibited apoptosis, promoted the miR-125b expression level, and regulated the p53 apoptotic pathway in post-infarction myocardium.

Topics: Animals; Apoptosis; bcl-2-Associated X Protein; Endothelial Cells; Exosomes; Mice; MicroRNAs; Myocardial Infarction; Myocardium; Tumor Suppressor Protein p53

Cardiovascular diseases are risk factors for dementia, but the mechanisms remain elusive. Here, we report that myocardial infarction (MI) generated by the ligation of the left coronary artery (LCA) could lead to increased miR-1 levels in the hippocampus and blood with neuronal microtubule damage and decreased TPPP/p25 protein expression in the hippocampus. These changes could be prevented by a knockdown of miR-1 using hippocampal stereotaxic injections of anti-miR-1 oligonucleotide fragments carried by a lentivirus vector (lenti-pre-AMO-miR-1). TPPP/p25 protein was downregulated by miR-1 overexpression, upregulated by miR-1 inhibition, and unchanged by binding-site mutations or miR-masks, indicating that the TPPP/p25 gene was a potential target for miR-1. Additionally, the pharmacological inhibition of sphingomyelinase by GW4869 to inhibit exosome generation in the heart significantly attenuated the increased miR-1 levels in the hippocampi of transgenic (Tg) and MI mice. Collectively, the present study demonstrates that MI could directly lead to neuronal microtubule damage independent of MI-induced chronic brain hypoperfusion but involving the overexpression of miR-1 in the hippocampus that was transported by exosomes from infarcted hearts. This study reveals a novel insight into the molecular mechanisms of heart-to-brain communication at the miRNA level.

Topics: Analysis of Variance; Aniline Compounds; Animals; Benzylidene Compounds; Cells, Cultured; Coculture Techniques; Disease Models, Animal; Exosomes; Genetic Vectors; Hippocampus; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; MicroRNAs; Microtubules; Myocardial Infarction; Myocytes, Cardiac; Nerve Tissue Proteins; Neurons; Phosphotransferases; Rats; Rats, Sprague-Dawley; Transfection

The CADUCEUS trial of cardiosphere-derived cells (CDCs) has shown that it may be possible to regenerate injured heart muscle previously thought to be permanently scarred. The mechanisms of benefit are known to be indirect, but the mediators have yet to be identified. Here we pinpoint exosomes secreted by human CDCs as critical agents of regeneration and cardioprotection. CDC exosomes inhibit apoptosis and promote proliferation of cardiomyocytes, while enhancing angiogenesis. Injection of exosomes into injured mouse hearts recapitulates the regenerative and functional effects produced by CDC transplantation, whereas inhibition of exosome production by CDCs blocks those benefits. CDC exosomes contain a distinctive complement of microRNAs, with particular enrichment of miR-146a. Selective administration of a miR-146a mimic reproduces some (but not all) of the benefits of CDC exosomes. The findings identify exosomes as key mediators of CDC-induced regeneration, while highlighting the potential utility of exosomes as cell-free therapeutic candidates.

Topics: Albumins; Aniline Compounds; Animals; Benzylidene Compounds; Cell Differentiation; Cell Proliferation; Cell- and Tissue-Based Therapy; Cells, Cultured; Disease Models, Animal; Exosomes; Fibroblasts; Human Umbilical Vein Endothelial Cells; Humans; Mice; Mice, Knockout; Mice, SCID; MicroRNAs; Myocardial Infarction; Myocytes, Cardiac; Neovascularization, Physiologic; Polyesters; Rats; Rats, Sprague-Dawley; Regeneration