ObjectiveTo comprehensively analyze the recent advancements in the field of mesenchymal stem cells (MSCs) derived exosomes (MSCs-exosomes) in tissue repair. MethodsThe literature about MSCs-exosomes in tissue repair was reviewed and analyzed. ResultsExosomes are biologically active microvesicles released from MSCs which are loaded with functional proteins, RNA, and microRNA. Exosomes can inhibit apoptosis, stimulate proliferation, alter cell phenotype in tissue repair of several diseases through cell-to-cell communication. ConclusionMSCs-exosomes is a novel source for the treatment of tissue repair. Further research of MSCs-exosomes biofunction, paracellular transport, and treatment mechanism will help the transform to clinical application.
Exosomes are a type of tiny vesicles released by cells, which contain bioactive molecules such as proteins, nucleic acids, and lipids secreted by cells. Exosomes released by different cells play an important role in tumor development and metastasis. These exosomes can regulate the tumor microenvironment, promote the tumor growth and invasion, and participate in the process of distant metastasis by carrying specific proteins and nucleic acids. In addition, some biomarkers in exosomes can serve as potential biomarkers for early diagnosis and prognosis evaluation of osteosarcoma. This article reviews the research progress of exosomes in osteosarcoma, aiming to gain a deeper understanding of their mechanisms of action in this disease and provide a reference for the development of new treatment strategies and prognostic evaluation indicators.
ObjectiveTo investigate whether exosomes derived from atorvastatin (ATV)-pretreated human umbilical cord mesenchymal stem cells (ATV-MSC-EXO) alleviate high glucose-induced injury in human retinal vascular endothelial cells (HREC) via the protein kinase B (AKT)/endothelial nitric oxide synthase (eNOS) signaling pathway. MethodsThe optimal pretreatment concentration of ATV was determined using the cell counting Kit-8 (CCK-8) assay. Exosomes derived from mesenchymal stem cells (MSC-EXO) and ATV-pretreated MSC (ATV-MSC-EXO) were isolated and extracted, and their morphology and surface markers were characterized by transmission electron microscopy, nanoparticle tracking analysis, and Western blotting (WB). The uptake capacity of exosomes by human retinal vascular endothelial cells (HREC) was evaluated using a fluorescence labeling assay. In vitro cultured HREC were divided into the following groups: normal control group (NC group), high glucose group (HG group), high glucose+MSC-EXO group (MSC-EXO group), high glucose+ATV-MSC-EXO group (ATV-MSC-EXO group), high glucose+ATV-MSC-EXO+AKT inhibitor group (ATV-MSC-EXO-MK-2206-2HCL group), and high glucose+ATV-MSC-EXO+eNOS inhibitor group (ATV-MSC-EXO-L-NAME group). Cell proliferation and apoptosis were detected using CCK-8 and flow cytometry, respectively. The protein expression levels of B-cell lymphoma/leukemia-2 (Bcl-2), Bcl-2-associated protein (Bax), and Caspase-3 were measured by WB. In addition, the regulatory effects of ATV-MSC-EXO on the AKT/eNOS signaling pathway and its downstream functional molecules were analyzed by detecting the phosphorylation levels of AKT (P-AKT/AKT) and eNOS (P-eNOS/eNOS) via WB, the mRNA expression levels of AKT and eNOS by quantitative real-time polymerase chain reaction, and the concentrations of nitric oxide (NO) and endothelin-1 (ET-1) using commercial NO and ET-1 assay kits. ResultsThe optimal pretreatment concentration of ATV was 1 μmol/L. ATV-MSC-EXO exhibited similar morphology and particle size to MSC-EXO and were efficiently taken up by HREC. Under high glucose conditions, ATV-MSC-EXO significantly enhanced the viability of HREC (F=83.24, P＜0.000 1) and inhibited apoptosis (F=77.39, P＜0.000 1). WB analysis further confirmed that ATV-MSC-EXO upregulated the expression of the anti-apoptotic protein Bcl-2 (F=53.17), while downregulating the pro-apoptotic proteins Bax (F=36.49) and Caspase-3 (F=60.75) (P＜0.001). In addition, ATV-MSC-EXO markedly increased the protein levels of P-AKT/AKT (F=107.60) and P-eNOS/eNOS (F=38.59), as well as the relative mRNA expression of AKT, eNOS (F=203.60, 315.00; P＜0.000 1). Furthermore, ATV-MSC-EXO promoted NO production (F=407.40) and suppressed the relative expression of ET-1 (F=49.76) (P＜0.000 1). ConclusionATV-MSC-EXO enhances the viability and inhibits apoptosis of HREC under high glucose conditions by activating the AKT/eNOS signaling pathway.
ObjectiveTo review the mechanisms of bioactive substances of mesenchymal stem cells-derived exosomes (MEX) in tissue repair and analyze the therapeutic values of MEX. MethodRecent relevant literature about MEX for tissue repair was extensively reviewed and analyzed. ResultsThe diameter of exosomes ranges from 30 to 100 nm which contain an abundance of bioactive substances, such as mRNA, microRNA, and protein. The majority of the exact bioactive substances in MEX, which are therapeutically beneficial to a wide range of diseases, are still unclear. ConclusionsBioactive substances contained in the MEX have repairing effect in tissue injury, which could provide a new insight for the clinical treatment of tissue damage. However, further studies are required to investigate the individual differences of MEX and the possible risk of accelerating cancer progression of MEX.
The study aims to explore the effect of mesenchymal stem cells-derived exosomes (MSCs-Exo) on staurosporine (STS)-induced chondrocyte apoptosis before and after exposure to pulsed electromagnetic field (PEMF) at different frequencies. The AMSCs were extracted from the epididymal fat of healthy rats before and after exposure to the PEMF at 1 mT amplitude and a frequency of 15, 45, and 75 Hz, respectively, in an incubator. MSCs-Exo was extracted and identified. Exosomes were labeled with DiO fluorescent dye, and then co-cultured with STS-induced chondrocytes for 24 h. Cellular uptake of MSC-Exo, apoptosis, and the protein and mRNA expression of aggrecan, caspase-3 and collagenⅡA in chondrocytes were observed. The study demonstrated that the exposure of 75 Hz PEMF was superior to 15 and 45 Hz PEMF in enhancing the effect of exosomes in alleviating chondrocyte apoptosis and promoting cell matrix synthesis. This study lays a foundation for the regulatory mechanism of PEMF stimulation on MSCs-Exo in inhibiting chondrocyte apoptosis, and opens up a new direction for the prevention and treatment of osteoarthritis.
Epilepsy is a common neurological disease with complex etiology and various seizure forms. It can affect people of all ages. Although a variety of antiseizure medications are available, one-third of patients still have poor drug treatment. Therefore, better methods for the diagnosis and treatment of epilepsy are particularly important. Exosomes are extracellular vesicles with a diameter of 30 ~ 150 nm that have powerful intercellular information transmission functions and also play an important role in the central nervous system. Exosomes released by nerve cells in the local microenvironment can participate in nerve development and plasticity, regulate neuroinflammation, and reduce neuronal loss. Moreover, some proteins or micro ribonucleic acid (miRNA) in exosomes are highly correlated with epilepsy and are changed in epileptogenesis, so they play an important role in the prevention and early diagnosis of epilepsy. In addition, exosomes have better biocompatibility and lower immunogenicity. Its small size can effectively avoid the phagocytosis of mononuclear macrophages. Moreover, the proteins carried on its surface have a strong homing ability to target tissues or cells and can penetrate the blood-brain barrier to the intracranial, so exosomes have the advantage of natural drug delivery. Therefore, this study reviews the application of exosomes in epilepsy to improve the understanding of exosomes in scientific research and clinical workers.
Objective To investigate the effects of exosomes from cultured human retinal pigment epithelium (ARPE-19) cells affected by oxidative stress on the proliferation and expression of vascular endothelial growth factor-A (VEGF-A) and Akt of ARPE-19 cells. Methods Culture ARPE-19 cells. The concentration of 2.5 μmol/L rotenone was selected to simulate oxidative stress and isolated ARPE-19-exosome. Exosomes were isolated by ExoQuick exosome precipitation solution. Transmission electron microscopy was used to identify the morphology of exosomes. Western blot was used to detect exosomes’ surface-specific maker protein CD63. ARPE-19 cells affected by oxidative stress were cultured with exosome as experimental group, normal ARPE-19 cells were cultured with exosome as control group. The cell proliferation was examined by methyl thiazolyl tetrazolium assay. Western blot and immunofluorescence assay were used to detect the expression levels of VEGF-A and Akt protein. Real-time quantitative polymerase chain reaction (RT-PCR) was used to detect the levels of VEGF-A mRNA and Akt mRNA. Results The diameter of normal ARPE-19-exosomes ranged from 50 to 150 nm. The isolated exosomes expressed CD63. AREP-19 cells were cultured with ARPE-19 (affected by rotenone)-exosome, the cell viability in experimental group was significantly reduced than in the control group. Green fluorescence was observed in the cytoplasm under fluorescence microscope. Compared with the control group, VEGF-A was up-regulated expressed and Akt was down-regulated expressed. Western blot results showed that, VEGF-A protein expression in the experimental group were higher than the control group. Akt protein expression in the experimental group were less than the control group. The difference was statically significant (t=3.822, 6.527;P＜0.05). RT-PCR results showed that VEGF-A mRNA expression levels was higher in the experimental group than the control group. Akt mRNA expression levels was lower in the experimental group than the control group. The difference was statically significant (t=8.805, −7.823;P＜0.05). Conclusions Exosomes from ARPE-19 cells affected by oxidative stress inhibit the proliferation of normal ARPE-19 cells, increase the expression of VEGF-A and reduce the expression of Akt.
Exosomes are nanovesicles actively secreted by cells, which selectively encapsulate biologically active molecules such as proteins, RNA, and cytokines. They play an important role in intercellular communication, immune regulation, and maintenance of homeostasis, which can also be used as carriers for targeted drug delivery. Retinal ischemia-reperfusion injury (RIRI) is a retinopathy that seriously threatens human vision. At present, the clinical treatment of these diseases are symptomatic treatments, and some patients have poor efficacy or even blindness. As extracellular vesicles rich in functional proteins and RNAs, exosomes can not only be used as drugs for the treatment of RIRI, but also be used as carriers for drug delivery to play synergistic therapeutic effects. In the future, with the deepening of the research on the molecular structure, contents and biological functions of exosomes, as well as the continuous development of ophthalmic biology and genetic engineering technology, exosomes are expected to exert their great potential as therapeutic drugs and carriers, and become an important means of treating RIRI.
ObjectiveTo observe the effects of exosomes derived from rat mesenchymal stem cells (MSC-exosomes) on the rat experimental autoimmune uveitis (EAU) model.MethodsTwelve Lewis rats were randomly divided into experimental group and control group by random number table, with 6 rats in each group. Rats in the experimental group were established with EAU model, 100 μl of MSC-exosomes (50 μg) were periocular injected on the 9th day after modeling while the control rats were injected with the same volume of phosphate buffer. At different time points after modeling, the retinal structure was observed by hematoxylin and eosin (HE) staining, and the clinical and pathological manifestations were evaluated. T cells from the two groups were analyzed by flow cytometry. Immunohistochemical staining was used to observe the expression of macrophage surface marker CD68. The effect of MSC-exosomes on T cells was measured by lymphocyte proliferation assays. And flow cytometry was used to detect Th1, Th17 and regulatory T cells Variety. Electroretinogram (ERG) was used to evaluate the retinal function. Data were compared between the two groups using the t test.ResultsHE staining showed that the retina structure of the experimental group was more complete than that of the control group on the 15th day after modeling. Immunohistochemical staining showed that the positive expression of CD68 in the experimental group was significantly less than that in the control group. On the 15th day after modeling, the retinal pathological score of the experimental group was lower than that of the control group. On the 9th to 13th day after modeling, compared to the control group, the average clinical scores of the retina in the experimental group were lower, and the difference was statistically significant (t=3.665, 3.21, 3.181, 4.121, 3.227; P＜0.01). The results of T cell proliferation assay showed that exosomes (1.0, 10.0 μg/ml) inhibited the proliferation of T cells under different concentrations of R16 (1, 10, 30 μg/ml), and the difference was statistically significant (F=11.630, 4.188, 6.011; P＜0.05). The results of flow cytometry showed that the number of Th1, Th17 and Treg cell subsets in the experimental group was decreased compared with the control group, and the difference was statistically significant (t=7.374, 4.525, 6.910; P＜0.01). There was no difference in the proportion of cells in the T cells and lymph nodes (t=1.126, 0.493, 0.178; P=0.286, 0.632, 0.862). The results of ERG showed that, compared with the control group, the amplitudes of 0.01, 3.0 cd/m2 a wave and b wave of the experiment group were all increased on the 15th day after modeling, and the differences were statistically significant (t=3.604, 4.178, 4.551, 2.566, P＜0.05).ConclusionsMSC-exosomes can reduce the clinical and pathological manifestations of EAU, protect retinal function, reduce ocular macrophage infiltration, down-regulate the proportion of inflammatory cells in the eye, and inhibit T cell proliferation.
ObjectiveTo observe the effect of exosomes secreted by retinal pigment epithelial (RPE) cells which damaged by blue light to Nod-like receptor protein (NLRP3).MethodsCultured ARPE-19 cells were divided into 2 groups; one group of RPE cells were exposed to blue light irradiation for 6 hours, the other group was cultured in routine environment. Total exosomes were extracted from the two groups by differential ultracentrifugation in low-temperature, and examined by transmission electron microscope to identify their forms. The exosomes were then incubated with normal ARPE-19 cells. The expression level of CD63, interleukin (IL)-1β, IL-18 and caspase-1 on the exosome surface were measured by Western blotting. The expressions of NLRP3 mRNA in RPE cells were detected by real-time fluorescence quantitative reverse transcription polymerase chain reaction (RT-PCR).ResultsBlue light damaged the cellular morphology. Transmission electron microscopy showed that the exosomes were 50-200nm in diameter and like double-concave disks. Blue light damaged cell-derived exosomes had significantly higher expression of IL-1β (t=18.04), IL-18 (t=12.55) and caspase-1 (t=14.70) than the control group (P＜0.001). ARPE-19 cells cultured with blue light damaged cell-derived exosomes also had significantly higher expression of IL-1β (t=18.59), IL-18 (t=23.95) and caspase-1 (t=35.27) than control exosomes (P＜0.001). RT-PCR showed that the relative expression of NLRP3 mRNA of PRE cells in experimental group and control group were 1.000±0.069 and 0.2±0.01, respectively, the difference was significant (t=12.20, P＜0.001).ConclusionThe expression IL-1β, IL-18 and caspase-1 and NLRP3 mRNA were upregulated by exosomes secreted by blue light damaged-RPE cells.