The miR-21-5p enriched in the apoptotic bodies of M2 macrophage-derived extracellular vesicles alleviates osteoarthritis by changing macrophage phenotype

Macrophages (Mφs) play a crucial role in the pathological progression of osteoarthritis (OA) by regulating inflammation and tissue repair. Decreasing pro-inflammatory M1-Mφs and increasing anti-inflammatory M2-Mφs can alleviate OA-related inflammation and promote cartilage repair. Apoptosis is a natural process associated with tissue repair. A large number of apoptotic bodies (ABs), a type of extracellular vesicle, are produced during apoptosis, and this is associated with a reduction in inflammation. However, the functions of apoptotic bodies remain largely unknown. In this study, we investigated the role of M2-Mφs-derived apoptotic bodies (M2-ABs) in regulating the M1/M2 balance of macrophages in a mouse model of OA. Our data show that M2-ABs can be targeted for uptake by M1-Mφs, and this reprograms M1-to-M2 phenotypes within 24 h. The M2-ABs significantly ameliorated the severity of OA, alleviated the M1-mediated pro-inflammatory environment, and inhibited chondrocyte apoptosis in mice. RNA-seq revealed that M2-ABs were enriched with miR-21–5p, a microRNA that is negatively correlated with articular cartilage degeneration. Inhibiting the function of miR-21–5p in M1-Mφs significantly reduced M2-ABs-guided M1-to-M2 reprogramming following in vitro cell transfection. Together, these results suggest that M2-derived apoptotic bodies can prevent articular cartilage damage and improve gait abnormalities in OA mice by reversing the inflammatory response caused by M1 macrophages. The mechanism underlying these findings may be related to miR-21-5p-regulated inhibition of inflammatory factors. The application of M2-ABs may represent a novel cell therapy, and could provide a valuable strategy for the treatment of OA and/or chronic inflammation.

In situ delivery of apoptotic bodies derived from mesenchymal stem cells via a hyaluronic acid hydrogel:A therapy for intrauterine adhesions

Stem cell-based and stem cell-derived exosome-based therapies have shown promising potential for endometrial regeneration and the clinical treatment of intrauterine adhesions(IUAs).Evidence shows that apoptosis occurs in a majority of grafted stem cells,and apoptotic bodies(ABs)play a critical role in compensatory tissue regeneration.However,the therapeutic potential of AB-based therapy and its mechanism have not been explored in detail.Here,a cell-free therapeutic strategy was developed by incorporating mesenchymal stem cell-derived ABs into a hyaluronic acid(HA)hydrogel to achieve endometrial regeneration and fertility restoration.Specifically,we found that the ABs could induce macrophage immunomodulation,cell proliferation,and angiogenesis in vitro.The HA hydrogel promoted the retention of ABs and facilitated their continuous release.In a murine model of acute endometrial damage and a rat model of IUAs,in situ injection of the AB-laden HA hydrogel could efficiently reduce fibrosis and promote endometrial regeneration,resulting in the fertility restoration.Consequently,ABs show good potential as therapeutic vesicles,and the AB-laden HA hydrogel appears to be a clinically feasible and cell-free alternative for endometrial regeneration and IUA treatment.

Engineered neutrophil apoptotic bodies ameliorate myocardial infarction by promoting macrophage efferocytosis and inflammation resolution

Inflammatory response plays a critical role in myocardial infarction(MI)repair.The neutrophil apoptosis and subsequent macrophage ingestion can result in inflammation resolution and initiate regeneration,while the therapeutic strategy that simulates and enhances this natural process has not been established.Here,we constructed engineered neutrophil apoptotic bodies(eNABs)to simulate natural neutrophil apoptosis,which regulated inflammation response and enhanced MI repair.The eNABs were fabricated by combining natural neutrophil apoptotic body membrane which has excellent inflammation-tropism and immunoregulatory properties,and mesoporous silica nanoparticles loaded with hexyl 5-aminolevulinate hydrochloride(HAL).The eNABs actively targeted to macrophages and the encapsulated HAL simultaneously initiated the biosynthesis pathway of heme to produce anti-inflammatory bilirubin after intracellular release,thereby further enhancing the anti-inflammation effects.In in vivo studies,the eNABs efficiently modulated inflammation responses in the infarcted region to ameliorate cardiac function.This study demonstrates an effective biomimetic construction strategy to regulate macrophage functions for MI repair.

Local anesthetic lidocaine induces apoptosis in human corneal stromal cells in vitro

AIM:To demonstrate the apoptosis-inducing effect of iidocalne on human corneal stromal(HCS)cells fn vitm,and provide experimental basis for safety anesthetic usage In clinic of ophthalmology.METHODS:In vitro cultured HCS cells were treated with lidocaine at different doses and times,and their morphology was monitored successively with inverted phase contrast microscopy.The membrane permeability of them was detected by acridine orange/ethidium bromide(AO/EB)double staining.The DNA fragmentation of them was examined by agarose gel electrophoresis,and their ultrastructure was observed by transmission electron microscopy(TEM),respectively.RESULTS:Exposure to lidocaine at doses from0.3125g/L to 20g/L induced morphological changes of HCS cells such as cytoplasmic vacuolation,cellular shrinkage,and turning round,and elevated membrane permeability of these cells in AO/EB staining.The change of morphology and membrane permeability was doseand time-dependent,while lidocaine at dose below0.15625g/L could not induce these changes.Furthermore,lidocaine induced DNA fragmentation and ultrastructural changes such as cytoplasmic vacuolation,structural disorganization,chromatin condensation,and apoptotic body appearance of the cells.CONCLUSION:Lidocaine has significant cytotoxicity on human corneal stromal cells in vitro in a dose-and time-dependent manner by inducing apoptosis of these cells.The established experimental model and findingsbased on this model here help provide new insight into the apoptosis-inducing effect of local anesthetics in eye clinic.

利用"Find-eat"策略通过受体功能化凋亡小体纳米囊泡靶向内皮细胞

慢性创面的缺氧微环境导致血管化不足,进而使得伤口延迟愈合.内皮细胞作为组成新生血管的关键细胞,在血管化过程中发挥着核心作用.本研究构建了CX3CR1功能化凋亡小体纳米囊泡(nABs).“Find-eat”策略通过受体-配体组合,靶向低氧微环境中高表达CX3CR1的内皮细胞(ECs),从而放大“Find-eat”信号,促进血管生成.作者首先通过化学诱导脂肪干细胞(ADSCs)凋亡获得ABs,然后通过优化的低渗处理-温和超声-药物混合-挤压一系列处理步骤,获得载有去铁胺(DFO)的功能化凋亡小体纳米囊泡.体外实验显示ABs纳米囊泡生物相容性良好;可以通过CX3CL1/CX3CR1诱导缺氧微环境中的内皮细胞实现对其的“Find-eat”,进而促进内皮细胞的增殖、迁移、成管能力.体内实验中,ABs纳米囊泡可以促进伤口快速闭合,并可通过释放“Find-eat”信号靶向内皮细胞的同时实现促血管药物的缓释,促进糖尿病大鼠创面的新生血管形成.这种能够通过释放双重信号靶向内皮细胞并实现促血管药物缓释的ABs纳米囊泡为慢性糖尿病创面的愈合提供了一种新思路.

Horizontal transfer of microRNAs: molecular mechanisms and clinical applications

A new class of RNA regulatory genes known as microRNAs(miRNAs)has been found to introduce a whole new layer of gene regulation in eukaryotes.The intensive studies of the past several years have demonstrated that miRNAs are not only found intracellularly,but are also detectable outside cells,including in various body fluids(e.g.serum,plasma,saliva,urine and milk).This phenomenon raises questions about the biological function of such extracellular miRNAs.Substantial amounts of extracellular miRNAs are enclosed in small membranous vesicles(e.g.exosomes,shedding vesicles and apoptotic bodies)or packaged with RNA-binding proteins(e.g.high-density lipoprotein,Argonaute 2 and nucleophosmin 1).These miRNAs may function as secreted signaling molecules to influence the recipient cell phenotypes.Furthermore,secreted extracellular miRNAs may reflect molecular changes in the cells from which they are derived and can therefore potentially serve as diagnostic indicators of disease.Several studies also point to the potential application of siRNA/miRNA delivery as a new therapeutic strategy for treating diseases.In this review,we summarize what is known about the mechanism of miRNA secretion.In addition,we describe the pathophysiological roles of secreted miRNAs and their clinical potential as diagnostic biomarkers and therapeutic drugs.We believe that miRNA transfer between cells will have a significant impact on biological research in the coming years.