Exosomes from MiR-126-Overexpressing Adscs Are Therapeutic in Relieving Acute Myocardial Ischaemic Injury.

Recent studies have indicated that exosomes play an important role in adipose-derived stem cell (ADSC) transplant-mediated ischaemic heart disease therapy. However, the treatment effect is not obvious. The aim of this study is to investigate whether ADSC-derived exosomes enriched with microRNA (miR)-126 have a more protective effect on acute myocardial infarction (AMI). Exosomes were characterized by transmission electron microscopy, and the exosome particles were further examined using nanoparticle tracking analyses. A rat model of myocardial infarction and in vitro model of hypoxia-induced H9c2 myocardial cell injury were established to study the protective mechanism of exosomes from miR-126-overexpressing ADSCs. The in vitro results showed that exosomes derived from miR-126-overexpressing ADSCs decreased H9c2 myocardial cell injury by reducing inflammation factor expression during hypoxia induction. The miR-126-enriched exosomes also decreased the expression of fibrosis-related proteins of H9c2 cells under hypoxic conditions. Matrigel® and Transwell® assays showed that miR-126-enriched exosomes significantly promoted microvascular generation and migration, respectively. In vivo studies confirmed that exosomes derived from ADSCs significantly decreased the myocardial injury area of infarction, especially after miR-126-enriched exosome treatment. Cardiac fibrosis and inflammatory cytokine expression were also decreased after treatment with miR-126-enriched exosomes. However, blood vessel formation was promoted in the infarction region of AMI rats. The results suggested that the expression of miR-126-enhanced ADSC-derived exosomes prevented myocardial damage by protecting myocardial cells from apoptosis, inflammation, fibrosis, and increased angiogenesis.

Luo Q ，Guo D ，Liu G ，Chen G ，Hang M ，Jin M ... -  《-》

Exosomes derived from miR-146a-modified adipose-derived stem cells attenuate acute myocardial infarction-induced myocardial damage via downregulation of early growth response factor 1.

Multiple studies demonstrated that early growth response factor 1 (EGR1) induces myocardial damage after acute myocardial infarction (AMI). Recent evidence indicates that microRNAs (miRNA) play an important role in exosome-mediated cardioprotection after AMI. Bioinformatics analysis has shown that miR-146a can regulate the expression of EGR1, so the aim of this study was to determine if miR-146a plays a role in exosome-mediated cardioprotection by regulation of EGR1 after AMI. Exosomes were isolated from wild- or miR-146a-modified adipose-derived stem cells (ADSCs), and the therapeutic effect of exosomes was assessed in an AMI model in rats and hypoxic-induced H9c2 model cells. The results showed that miR-146a containing exosomes had more effect than the exosome treatment group on the suppression of AMI-induced apoptosis, inflammatory response, and fibrosis in an AMI rat model. Both in vivo and in vitro experiments found that miR-146a interacted with the 3'-untranslated region of EGR1 and suppressed posttranscriptional EGR1 expression, which was confirmed by the luciferase reporter assay. We also found that suppressed EGR1 expression reversed AMI or hypoxia-induced TLR4/NFκB signal activation, which played an important role in the promotion of myocardial cell apoptosis, inflammatory response, and fibrosis. Taken together, these findings suggested that exosomes derived from miR-146a-modified ADSCs attenuated AMI-induced myocardial damage via downregulation of EGR1.

Pan J ，Alimujiang M ，Chen Q ，Shi H ，Luo X ... -  《-》

Exosomes from MiR-30d-5p-ADSCs Reverse Acute Ischemic Stroke-Induced, Autophagy-Mediated Brain Injury by Promoting M2 Microglial/Macrophage Polarization.

Recent studies have indicated that exosomes secreted from adipose-derived stem cells (ADSCs) have important effects in the treatment of ischemic injury. However, the treatment mechanism is unclear. This study aimed to investigate whether ADSC-derived exosomes enriched with microRNA (miR)-30d-5p have a protective effect on acute ischemic stroke (AIS). In the current study, inflammatory factors and miR-30d-5p expression were assessed in 70 subjects with AIS and 35 healthy controls. Exosomes were characterized by transmission electron microscopy and further examined using nanoparticle tracking analyses. A rat model of AIS and an in vitro model of oxygen- and glucose-deprived (OGD) primary microglia were established to study the protective mechanism of exosomes from miR-30d-5p-overexpressing ADSCs in ischemia-induced nerve injury. The results showed that following AIS, the expression of inflammatory cytokines increased, while the anti-inflammatory cytokines IL-4, IL-10, and miR-30d-5p decreased both in patients and in animal models. Moreover, in vitro studies demonstrated that suppression of autophagy significantly reduced the OGD-induced inflammatory response. In addition, exosome treatment was more effective in suppressing the inflammatory response by reversing OGD-induced and autophagy-mediated microglial polarization to M1. Furthermore, in vivo studies showed that exosomes derived from ADSCs significantly decreased the cerebral injury area of infarction by suppressing autophagy and promoting M2 microglia/macrophage polarization. Our results suggest that miR-30d-5p-enhanced ADSC-derived exosomes prevent cerebral injury by inhibiting autophagy-mediated microglial polarization to M1.

Jiang M ，Wang H ，Jin M ，Yang X ，Ji H ，Jiang Y ，Zhang H ，Wu F ，Wu G ，Lai X ，Cai L ，Hu R ，Xu L ，Li L ... -  《-》

Exosomes from adipose-derived mesenchymal stem cells ameliorate cardiac damage after myocardial infarction by activating S1P/SK1/S1PR1 signaling and promoting macrophage M2 polarization.

Exosomes derived from mesenchymal stem cells (MSCs) are known to participate in myocardial repair after myocardial infarction (MI), but the mechanism remains unclear. Here, we isolated exosomes from adipose-derived MSCs (ADSCs) and examined their effect on MI-induced cardiac damage. To examine the underlying mechanism, H9c2 cells, cardiac fibroblasts, and HAPI cells were used to study the effect of ADSC-exosomes on hypoxia-induced H9c2 apoptosis, TGF-β1-induced fibrosis of cardiac fibroblasts, and hypoxia-induced macrophage M1 polarization using qRT-PCR, western blot, ELISA, immunohistochemistry, immunofluorescence and flow cytometry. ADSC-exosome treatment mitigated MI-induced cardiac damage by suppressing cardiac dysfunction, cardiac apoptosis, cardiac fibrosis, and inflammatory responses in vitro and in vivo. In addition, ADSC-exosome treatment promoted macrophage M2 polarization. Further experiments found that S1P/SK1/S1PR1 signaling was involved in the ADSC-exosome-mediated myocardial repair. Silencing of S1PR1 reversed the inhibitory effect of ADSC-exosomes on MI-induced cardiac apoptosis and fibrosis in vitro. ADSC-exosome-induced macrophage M2 polarization was also reversed after downregulation of S1PR1 under hypoxia conditions, which promoted NFκB and TGF-β1 expression, and suppressed the MI-induced cardiac fibrosis and inflammatory response. In sum, these results indicate that ADSC-derived exosomes ameliorate cardiac damage after MI by activating S1P/SK1/S1PR1 signaling and promoting macrophage M2 polarization.

Deng S ，Zhou X ，Ge Z ，Song Y ，Wang H ，Liu X ，Zhang D ... -  《-》

Exosomes derived from miR-181-5p-modified adipose-derived mesenchymal stem cells prevent liver fibrosis via autophagy activation.

Proliferating hepatic stellate cells (HSCs) respond to liver damage by secreting collagens that form fibrous scar tissue, which can lead to cirrhosis if in appropriately regulated. Advancement of microRNA (miRNA) hepatic therapies has been hampered by difficulties in delivering miRNA to damaged tissue. However, exosomes secreted by adipose-derived mesenchymal stem cells (ADSCs) can be exploited to deliver miRNAs to HSCs. ADSCs were engineered to overexpress miRNA-181-5p (miR-181-5p-ADSCs) to selectively home exosomes to mouse hepatic stellate (HST-T6) cells or a CCl4-induced liver fibrosis murine model and compared with non-targeting control Caenorhabditis elegans miR-67 (cel-miR-67)-ADSCs. In vitro analysis confirmed that the transfer of miR-181-5p from miR-181-5p-ADSCs occurred via secreted exosomal uptake. Exosomes were visualized in HST-T6 cells using cyc3-labelled pre-miRNA-transfected ADSCs with/without the exosomal inhibitor, GW4869. The effects of miRNA-181-5p overexpression on the fibrosis associated STAT3/Bcl-2/Beclin 1 pathway and components of the extracellular matrix were assessed. Exosomes from miR181-5p-ADSCs down-regulated Stat3 and Bcl-2 and activated autophagy in the HST-T6 cells. Furthermore, the up-regulated expression of fibrotic genes in HST-T6 cells induced by TGF-β1 was repressed following the addition of isolated miR181-5p-ADSC exosomes compared with miR-67-ADSCexosomes. Exosome therapy attenuated liver injury and significantly down-regulated collagen I, vimentin, α-SMA and fibronectin in liver, compared with controls. Taken together, the effective anti-fibrotic function of engineered ADSCs is able to selectively transfer miR-181-5p to damaged liver cells and will pave the way for the use of exosome-ADSCs for therapeutic delivery of miRNA targeting liver disease.

Qu Y ，Zhang Q ，Cai X ，Li F ，Ma Z ，Xu M ，Lu L ... -  《-》