Myocardial fibrosis is a common pathophysiological change in cardiovascular disease, which can cause cardiac dysfunction and even sudden death. Excessively activated fibroblasts proliferate and secret excessive extracellular matrix (ECM) components, resulting in normal cardiac structural damage and cardiac fibrosis. We previously found that human endothelial progenitor cell (EPC)-derived exosomes, after hypoxia/reoxygenation (H/R) induction, could significantly increase the mesenchymal-endothelial transition (MEndoT) compared to normal culture EPC-derived exosomes. Exosomes have been shown to carry different nucleic acids, including microRNAs. However, the effects of microRNAs in EPC-derived exosomes on MEndoT and myocardial fibrosis remain unknown. EPCs were isolated from human peripheral blood, and fibroblasts were isolated from rat hearts, then transfected with miR-133 inhibitor, si-YBX-1, and ov-YBX-1 into EPCs. After H/R induction for 48 h, isolation and characterization of exosomes derived from human EPCs were performed. Finally, fibroblasts were treated by exosome at 48 h. The expression of miR-133 was measured by qRT-PCR; YBX-1 expression was measured by qRT-PCR and western blot. Angiopoiesis was measured by tube formation assay. Endothelial markers and fibrosis markers were measured by western blot. H/R treatment promoted miR-133 expression in EPCs and EPC-derived exosomes. miR-133 could be incorporated into exosomes and transmitted to cardiac fibroblasts, increasing the angiogenesis and MEndoT of cardiac fibroblasts. miR-133 silencing in H/R-induced EPCs could inhibit miR-133 expression in EPCs and EPCs-derived exosomes. miR-133 silencing in H/R-induced EPCs could inhibit the angiogenesis and MEndoT of cardiac fibroblasts and reverse the effect of H/R treatment. Additionally, miR-133 was specially sorted into H/R-induced EPC-derived exosomes via YBX-1. YBX-1 silencing inhibited miR-133 transfer and reduced fibroblast angiogenesis and MEndoT. miR-133 was specially sorted into H/R-induced EPC-derived exosomes via YBX-1 to increase fibroblast angiogenesis and MEndoT.

Accumulating evidence has shown that endothelial progenitor cell‐derived exosomes (EPC‐Exos) can ameliorate myocardial fibrosis. The purpose of the present study was to investigate the effects of EPC‐Exos‐derived microRNAs (miRNAs) on myocardial infarction (MI). A miRNA‐Seq dataset of miRNAs differentially expressed between EPCs and exosomes was collected. Quantitative real‐time polymerase chain reaction (qRT‐PCR) was used to validate the miRNA expression indicated by miRNA‐Seq. Immunofluorescence, cell proliferation, and angiogenesis assays were employed to investigate the effects of miRNAs on cardiac fibroblasts (CFs) in vitro. Interactions between miRNAs and their respective targets were examined via immunoblotting, qRT‐PCR, and luciferase reporter assays. An MI rat model was constructed, and various staining and immunohistochemical assays were performed to explore the mechanisms underlying the miRNA‐mediated effects on MI. miR‐363‐3p and miR‐218‐5p were enriched in EPC‐Exos, and miR‐218‐5p and miR‐363‐3p mimic or inhibitor enhanced or suppressed CF proliferation and angiogenesis, respectively. miR‐218‐5p and miR‐363‐3p regulated p53 and junction‐mediating and regulatory protein (JMY) by binding to the promoter region of p53 and the 3 ^′ untranslated region of JMY. Additionally, treatment of CFs with Exo‐miR‐218‐5p or Exo‐miR‐363‐3p upregulated p53 and downregulated JMY expression, promoted mesenchymal‐endothelial transition, and inhibited myocardial fibrosis. Administration of exosomes containing miR‐218‐5p mimic or miR‐363‐3p mimic ameliorated left coronary artery ligation‐induced MI and restored myocardial tissue integrity in the MI model rats. In summary, these results show that the protective ability of EPC‐Exos against MI was mediated by the shuttled miR‐218‐5p or miR‐363‐3p via targeting of the p53/JMY signaling pathway.

Background: Percutaneous transluminal coronary angioplasty (PTCA) represents an efficient therapeutic method for atherosclerosis but conveys a risk of causing restenosis. Endothelial colony-forming cell-derived exosomes (ECFC-exosomes) are important mediators during vascular repair. This study aimed to investigate the therapeutic effects of ECFC-exosomes in a rat model of atherosclerosis and to explore the molecular mechanisms underlying the ECFC-exosome-mediated effects on ox-LDL-induced endothelial injury.Methods: The effect of ECFC-exosome-mediated autophagy on ox-LDL-induced human microvascular endothelial cell (HMEC) injury was examined by cell counting kit-8 assay, scratch wound assay, tube formation assay, western blot and the Ad-mCherry-GFP-LC3B system. RNA-sequencing assays, bioinformatic analysis and dual-luciferase reporter assays were performed to confirm the interaction between the miR-21-5p abundance of ECFC-exosomes andSIPA1L2in HMECs. The role and underlying mechanism of ECFC-exosomes in endothelial repair were explored using a high-fat diet combined with balloon injury to establish an atherosclerotic rat model of vascular injury. Evans blue staining, haematoxylin and eosin staining and western blotting were used to evaluate vascular injury.Results: ECFC-exosomes were incorporated into HMECs and promoted HMEC proliferation, migration and tube formation by repairing autophagic flux and enhancing autophagic activity. Subsequently, we demonstrated that miR-21-5p, which is abundant in ECFC-exosomes, binds to the 3’ untranslated region of SIPA1L2 to inhibit its expression, and knockout of miR-21-5p in ECFC-exosomes reversed ECFC-exosome-decreased SIPA1L2 expression in ox-LDL-induced HMEC injury. Knockdown of SIPA1L2 repaired autophagic flux and enhanced autophagic activity to promote cell proliferation in ox-LDL-treated HMECs. ECFC-exosome treatment attenuated vascular endothelial injury, regulated lipid balance and activated autophagy in an atherogenic rat model of vascular injury, whereas these effects were eliminated with ECFC-exosomes with knockdown of miR-21-5p.Conclusions: Our study demonstrated that ECFC-exosomes protect against atherosclerosis- or PTCA-induced vascular injury by rescuing autophagic flux and inhibiting SIAP1L2 expression through delivery of miR-21-5p.

Myocardial infarction (MI) remains a leading cause of morbidity and mortality worldwide. Endothelial progenitor cell (EPC)-derived exosomes have been found to be effective in alleviating MI, while the detailed mechanisms remain unclear. The present study aimed to determine the protective effects of EPC-derived exosomal miR-1246 and miR-1290 on MI-induced injury and to explore the underlying molecular mechanisms. The exosomes were extracted from EPCs; gene expression levels were determined by quantitative real-time PCR, and protein expression levels were determined by western blot and immunofluorescence staining, respectively. The angiogenesis and proliferation of human cardiac fibroblasts (HCFs) were determined by tube formation assay and immunofluorescence staining of PKH67, respectively. Luciferase reporter, CHIP, and EMSA assays determined the interaction between miR-1246/1290 and the targeted genes (EFL5 and SP1). The protective effects of miR-1246/1290 on MI were evaluated in a rat model of MI. EPC-derived exosomes significantly upregulated miR-1246 and miR-1290 expression and promoted phenotypic changes of fibroblasts to endothelial cells, angiogenesis, and proliferation in HCFs. Exosomes from EPCs with miR-1246 or miR-1290 mimics transfection promoted phenotypic changes of fibroblasts to endothelial cells and angiogenesis in HCFs, while exosomes from EPCs with miR-1246 or miR-1290 knockdown showed opposite effects in HCFs. Mechanistically, miR-1246 and miR-1290 from EPC-derived exosomes induced upregulation of ELF5 and SP1, respectively, by targeting the promoter regions of corresponding genes. Overexpression of both ELF5 and SP1 enhanced phenotypic changes of fibroblasts to endothelial cells and angiogenesis in HCFs pretreated with exosomes from EPCs with miR-1246 or miR-1290 mimics transfection, while knockdown of both EFL5 and SP1 exerted the opposite effects in HCFs. Both ELF5 and SP1 can bind to the promoter of CD31, leading to the upregulation of CD31 in HCFs. Furthermore,in vivoanimal studies showed that exosomes from EPCs with miR-1246 or miR-1290 overexpression attenuated the MI-induced cardiac injury in the rats and caused an increase in ELF5, SP1, and CD31 expression, respectively, but suppressed α-SMA expression in the cardiac tissues. In conclusion, our study revealed that miR-1246 and miR-1290 in EPC-derived exosomes enhancedin vitroandin vivoangiogenesis in MI, and these improvements may be associated with amelioration of cardiac injury and cardiac fibrosis after MI.

Ultrathin two‐dimensional transition‐metal dichalcogenides (TMDs) have been pursued extensively in recent years for interesting physics and application potentials. For the latter, it is essential to synthesize crystalline TMD monolayers at wafer‐scale. Here, we report growth of single‐crystalline MSe₂ (M = Mo, W) monolayers at wafer‐scale by molecular‐beam epitaxy at low temperatures (200–400°C) on nominally flat Au(1 1 1) substrates. The epifilms have low intrinsic defect densities of low 10¹² cm⁻². The grown films have then been exfoliated and transferred onto SiO₂/Si by a wet chemical process, on which some optical measurements are performed, revealing high spatial uniformity of the samples. We also establish that MSe₂ grows on Au via the van der Waals epitaxy mechanism, where a continuous film extends across the whole surface, overhangs atomic‐layer steps on substrate. We identify that the growth of highly crystalline MSe₂ is promoted by an enhanced interaction between Au substrate and MSe₂ islands rather than by the guidance of surface steps on substrate. The latter only arrests MSe₂ lateral growth if they are multilayer high.Key points: MBE growth of wafer‐scale highly crystalline TMD monolayers at low‐temperature is achieved. Island‐substrate interaction is found to play a critical role in vdW epitaxy of single‐crystalline TMDs on on‐axis substates. The TMD monolayers are of high uniformity and low intrinsic defect density.

Background: Carthamus tinctorius L., a traditional herbal medicine used for atherosclerosis (AS), lacks a clear understanding of its therapeutic mechanisms. This study aimed to investigate the therapeutic effects and mechanisms of Carthamus tinctorius L.-derived nanovesicles (CDNVs) in AS treatment. Methods: CDNVs were isolated and characterized using improved isolation methods. Transmission electron microscopy, nanoparticle tracking analysis, and protein analysis confirmed their morphology, size, and protein composition. Small RNA sequencing was performed to identify the miRNA profile of CDNVs, and bioinformatics analysis was used to determine their potential biological roles. In vivo biodistribution and toxicity studies were conducted in mice to assess the stability and safety of orally administered CDNVs. The anti-atherosclerotic effects of CDNVs were evaluated in ApoE-/- mice through plaque burden analysis. The protective effects of CDNVs on ox-LDL-treated endothelial cells were assessed through proliferation, apoptosis, reactive oxygen species activation, and monocyte adhesion assays. miRNA and mRNA sequencing of CDNV-treated endothelial cells were performed to explore their regulatory effects and potential target genes. Results: CDNVs were successfully isolated and purified from Carthamus tinctorius L. tissue lysates. They exhibited a saucer-shaped or cup-shaped morphology, with an average particle size of 142.6 ± 0.7 nm, and expressed EV markers CD63 and TSG101. CDNVs contained proteins, small RNAs, and metabolites, including the therapeutic compound HSYA. Small RNA sequencing identified 95 miRNAs, with 10 common miRNAs accounting for 72.63% of the total miRNAs. These miRNAs targeted genes involved in cell adhesion, apoptosis, and cell proliferation, suggesting their relevance in cardiovascular disease. Orally administered CDNVs were stable in the gastrointestinal tract, absorbed into the bloodstream, and accumulated in the liver, lungs, heart, and aorta. They significantly reduced the burden of atherosclerotic plaques in ApoE-/- mice and exhibited superior effects compared to HSYA. In vitro studies demonstrated that CDNVs were taken up by HUVECs, promoted proliferation, attenuated ox-LDL-induced apoptosis and ROS activation, and reduced monocyte adhesion. CDNV treatment resulted in significant changes in miRNA and mRNA expression profiles of HUVECs, with enrichment in inflammation-related genes. CXCL12 was identified as a potential direct target of miR166a-3p. Conclusion: CDNVs isolated from Carthamus tinctorius L. tissue lysates represent a promising oral therapeutic option for cardiovascular diseases. The delivery of miRNAs by CDNVs regulates inflammation-related genes, including CXCL12, in HUVECs, suggesting their potential role in modulating endothelial inflammation. These findings provide valuable insights into the therapeutic potential of CDNVs and their miRNAs in cardiovascular disease.