Immunomodulatory extracellular vesicles: an alternative to cell therapy for COVID-19

Exosomes derived from M2 macrophages prevent steroid-induced osteonecrosis of the femoral head by modulating inflammation, promoting bone formation and inhibiting bone resorption

Inflammatory reactions are involved in the development of steroid-induced osteonecrosis of the femoral head(ONFH). Studies have explored the therapeutic efficacy of inhibiting inflammatory reactions in steroid-induced ONFH and revealed that inhibiting inflammation may be a new strategy for preventing the development of steroid-induced ONFH. Exosomes derived from M2 macrophages(M2-Exos) display anti-inflammatory properties. This study aimed to examine the preventive effect of M2-Exos on early-stage steroid-induced ONFH and explore the underlying mechanisms involved. In vitro, we explored the effect of M2-Exos on the proliferation and osteogenic differentiation of bone marrow-derived mesenchymal stem cells(BMMSCs). In vivo, we investigated the role of M2-Exos on inflammation, osteoclastogenesis, osteogenesis and angiogenesis in an early-stage rat model of steroid-induced ONFH. We found that M2-Exos promoted the proliferation and osteogenic differentiation of BMMSCs. Additionally, M2-Exos effectively attenuated the osteonecrotic changes, inhibited the expression of proinflammatory mediators, promoted osteogenesis and angiogenesis, reduced osteoclastogenesis, and regulated the polarization of M1/M2 macrophages in steroid-induced ONFH. Taken together, our data suggest that M2-Exos are effective at preventing steroid-induced ONFH. These findings may be helpful for providing a potential strategy to prevent the development of steroid-induced ONFH.

Circ_0006640 transferred by bone marrow-mesenchymal stem cell-exosomes suppresses lipopolysaccharide-induced apoptotic, inflammatory and oxidative injury in spinal cord injury

BACKGROUND

Emerging proofs have shown that differentially expressed circular RNAs (circRNAs) are closely associated with the pathophysiological process of spinal cord injury (SCI). Mesenchymal stem cell (MSC)-exosomes have been demonstrated to possess favorable therapeutic effects in diseases. Herein, this work aimed to investigate the action of circ_0006640 transferred by MSC-exosomes functional recovery after SCI.

METHODS

SCI animal models were established by spinal cord contusion surgery in mice and lipopolysaccharide (LPS)-stimulated mouse microglial cell line BV2. Levels of genes and proteins were detected by qRT-PCR and Western blot. Properties of BV2 cells were characterized using CCK-8 assay, flow cytometry and ELISA analysis. The oxidative stress was evaluated. Dual-luciferase reporter assay was used for verifying the binding between miR-382-5p and circ_0006640 or IGF-1 (Insulin-like Growth Factor 1). Exosome separation was conducted by using the commercial kit.

RESULTS

Circ_0006640 expression was lower in SCI mice and LPS-induced microglial cells. Circ_0006640 overexpression protected microglial cells from LPS-induced apoptotic, inflammatory and oxidative injury. Mechanistically, circ_0006640 directly sponged miR-382-5p, which targeted IGF-1. MiR-382-5p was increased, while IGF-1 was decreased in SCI mice and LPS-induced microglial cells. Knockdown of miR-382-5p suppressed apoptosis, inflammation and oxidative stress in LPS-induced microglial cells, which were reversed by IGF-1 deficiency. Moreover, miR-382-5p up-regulation abolished the protective functions of circ_0006640 in LPS-induced microglial cells. Additionally, circ_0006640 was packaged into MSC-exosomes and could be transferred by exosomes. Exosomal circ_0006640 also had protective effects on microglial cells via miR-382-5p/IGF-1 axis.

CONCLUSION

Circ_0006640 transferred by BMSC-exosomes suppressed LPS-induced apoptotic, inflammatory and oxidative injury via miR-382-5p/IGF-1 axis, indicating a new insight into the clinical application of exosomal circRNA-based therapeutic in the function recovery after SCI.

Exosomes from bone marrow mesenchymal stem cells ameliorate glucocorticoid-induced osteonecrosis of femoral head by transferring microRNA-210 into bone microvascular endothelial cells

OBJECTIVES

Bone microvascular endothelial cells (BMECs) played an important role in the pathogenesis of glucocorticoid-induced osteonecrosis of femoral head (GCS-ONFH), and exosomes derived from bone marrow mesenchymal stem cells (BMSC-Exos) may provide an effective treatment. This study aimed to evaluate the effects of BMSC-Exos and internal microRNA-210-3p (miRNA-210) on GCS-ONFH in an in vitro hydrocortisone-induced BMECs injury model and an in vivo rat GCS-ONFH model.

METHODS

BMECs, BMSCs and BMSC-Exos were isolated and validated. BMECs after the treatment of hydrocortisone were cocultured with different concentrations of BMSC-Exos, then proliferation, migration, apoptosis and angiogenesis of BMECs were evaluated by CCK-8, Annexin V-FITC/PI, cell scratch and tube formation assays. BMSCs were transfected with miRNA-210 mimics and miRNA-210 inhibitors, then BMSC-ExosmiRNA-210 mimic and BMSC-ExosmiRNA-210 inhibitor secreted from such cells were collected. The differences between BMSC-Exos, BMSC-ExosmiRNA-210 mimic and BMSC-ExosmiRNA-210 inhibitor in protecting BMECs against GCS treatment were analyzed by methods mentioned above. Intramuscular injections of methylprednisolone were performed on Sprague-Dawley rats to establish an animal model of GCS-ONFH, then tail intravenous injections of BMSC-Exos, BMSC-ExosmiRNA-210 mimic or BMSC-ExosmiRNA-210 inhibitor were conducted after methylprednisolone injection. Histological and immunofluorescence staining and micro-CT were performed to evaluate the effects of BMSC-Exos and internal miRNA-210 on the in vivo GCS-ONFH model.

RESULTS

Different concentrations of BMSC-Exos, especially high concentration of BMSC-Exos, could enhance the proliferation, migration and angiogenesis ability and reduce the apoptosis rates of BMECs treated with GCS. Compared with BMSC-Exos, BMSC-ExosmiRNA-210 mimic could further enhance the proliferation, migration and angiogenesis ability and reduce the apoptosis rates of BMECs, while BMECs in the GCS + BMSC-ExosmiRNA-210 inhibitor group showed reduced proliferation, migration and angiogenesis ability and higher apoptosis rates. In the rat GCS-ONFH model, BMSC-Exos, especially BMSC-ExosmiRNA-210 mimic, could increase microvascular density and enhance bone remodeling of femoral heads.

CONCLUSIONS

BMSC-Exos containing miRNA-210 could serve as potential therapeutics for protecting BMECs and ameliorating the progression of GCS-ONFH.

Psoralen synergizes with exosome-loaded SPC25 to alleviate senescence of nucleus pulposus cells in intervertebral disc degeneration

OBJECTIVE

To explore the mechanism of psoralen synergized with exosomes (exos)-loaded SPC25 on nucleus pulposus (NP) cell senescence in intervertebral disc degeneration (IVDD).

METHODS

IVDD cellular models were established on NP cells by tert-butyl hydroperoxide (TBHP) induction, followed by the treatment of psoralen or/and exos from adipose-derived stem cells (ADSCs) transfected with SPC25 overexpression vector (ADSCs-oe-SPC25-Exos). The viability, cell cycle, apoptosis, and senescence of NP cells were examined, accompanied by the expression measurement of aggrecan, COL2A1, Bcl-2, Bax, CDK2, p16, and p21.

RESULTS

After TBHP-induced NP cells were treated with psoralen or ADSCs-oe-SPC25-Exos, cell proliferation and the expression of aggrecan, COL2A1, Bcl-2, and CDK2 were promoted; however, the expression of Bax, p16, p21, and inflammatory factors was decreased, and cell senescence, cycle arrest, and apoptosis were inhibited. Of note, psoralen combined with ADSCs-oe-SPC25-Exos further decelerated NP cell senescence and cycle arrest compared to psoralen or ADSCs-oe-SPC25-Exos alone.

CONCLUSION

Combined treatment of psoralen and ADSCs-oe-SPC25-Exos exerted an alleviating effect on NP cell senescence, which may provide an insightful idea for IVDD treatment.

Adipose-derived stem cell exosome NFIC improves diabetic foot ulcers by regulating miR-204-3p/HIPK2

BACKGROUND

Diabetic foot ulcers (DFU) are a serious complication of diabetes that lead to significant morbidity and mortality. Recent studies reported that exosomes secreted by human adipose tissue-derived mesenchymal stem cells (ADSCs) might alleviate DFU development. However, the molecular mechanism of ADSCs-derived exosomes in DFU is far from being addressed.

METHODS

Human umbilical vein endothelial cells (HUVECs) were induced by high-glucose (HG), which were treated with exosomes derived from nuclear factor I/C (NFIC)-modified ADSCs. MicroRNA-204-3p (miR-204-3p), homeodomain-interacting protein kinase 2 (HIPK2), and NFIC were determined using real-time quantitative polymerase chain reaction. Cell proliferation, apoptosis, migration, and angiogenesis were assessed using cell counting kit-8, 5-ethynyl-2'-deoxyuridine (EdU), flow cytometry, wound healing, and tube formation assays. Binding between miR-204-3p and NFIC or HIPK2 was predicted using bioinformatics tools and validated using a dual-luciferase reporter assay. HIPK2, NFIC, CD81, and CD63 protein levels were measured using western blot. Exosomes were identified by a transmission electron microscope and nanoparticle tracking analysis.

RESULTS

miR-204-3p and NFIC were reduced, and HIPK2 was enhanced in DFU patients and HG-treated HUVECs. miR-204-3p overexpression might abolish HG-mediated HUVEC proliferation, apoptosis, migration, and angiogenesis in vitro. Furthermore, HIPK2 acted as a target of miR-204-3p. Meanwhile, NFIC was an upstream transcription factor that might bind to the miR-204-3p promoter and improve its expression. NFIC-exosome from ADSCs might regulate HG-triggered HUVEC injury through miR-204-3p-dependent inhibition of HIPK2.

CONCLUSION

Exosomal NFIC silencing-loaded ADSC sheet modulates miR-204-3p/HIPK2 axis to suppress HG-induced HUVEC proliferation, migration, and angiogenesis, providing a stem cell-based treatment strategy for DFU.

Effect study of exosomes derived from platelet-rich plasma in the treatment of knee cartilage defects in rats

BACKGROUND

The repair of articular cartilage defects has always been a difficult problem. We aimed to investigate the therapeutic effect of intra-articular injection of platelet-rich plasma (RPR) and PRP-derived exosomes (PRP-Exos) on cartilage defects in rat knee joints and then provide experience for the use of PRP-exos in cartilage defect repair.

METHODS

Rat abdominal aortic blood was collected, and PRP was extracted by two-step centrifugation. PRP-exos were obtained by kit extraction, and PRP-exos were identified by various methods. After the rats were anesthetized, a cartilage defect subchondral bone was created at the proximal end of the origin of the femoral cruciate ligament with a drill. SD rats were divided into 4 groups, including PRP group, 50 μg/ml PRP-exos group, 5 μg/ml PRP-exos group, and control group. One week after the operation, 50 μg/ml PRP, 50 μg/ml PRP-exos, 5 μg/ml PRP-exos and normal saline were injected into the knee joint cavity of rats in each group, once a week. A total of two injections were given. On the 5th and 10th week after drug injection, the serum levels of matrix metalloproteinase 3 (MMP-3) and tissue inhibitor of matrix metalloproteinase 1 (TIMP-1) were detected by each treatment method, respectively. The rats were killed at the 5th and 10th weeks, respectively, and the cartilage defect repair was observed and scored. The defect repair tissue sections were used for HE staining and type II collagen immunohistochemical staining.

RESULTS

The histological results showed that both PRP-exos and PRP could promote cartilage defect repair and type II collagen formation, and the promoting effect of PRP-exos was significantly better than that of PRP. In addition, enzyme-linked immunosorbent assay (ELISA) results showed that compared with PRP, PRP-exos could significantly increase serum TIMP-1 and decrease serum MMP-3 in rats. And the promoting effect of PRP-exos was concentration dependent.

CONCLUSION

Intra-articular injection of PRP-exos and PRP can promote the repair of articular cartilage defects, and the therapeutic effect of PRP-exos is better than the same concentration of PRP. PRP-exos are expected to be an effective treatment for cartilage repair and regeneration.