Mesenchymal stem cell‐derived extracellular vesicles conditionally ameliorate bone marrow failure symptoms in an immune‐mediated aplastic anemia mouse model

Abstract

Acquired forms of Aplastic anemia (AA) are characterized by T cell‐mediated immune disease resulting in bone marrow (BM) failure and marrow hypoplasia. In these cases, it is a major challenge to modulate autoreactive T cell activity and thereby decrease the pro‐inflammatory cytokine storm. Emerging evidence indicates that extracellular vesicles derived from mesenchymal stem cells (MSC‐EVs) control and modulate immunity. The therapeutic potential of MSC‐EVs has not been investigated in acquired AA. Hence, in this study, we constructed an AA mice model through irradiation and splenocyte infusion to test the benefits of hypoxic MSC‐EVs (Hx‐EVs) and normoxic MSC‐EVs (Nx‐EVs). We found that MSC‐EVs treatment significantly prolonged the survival rate and increased the platelet (PLT) counts of the AA mice. Immunohistochemical staining and colony assay confirmed amelioration of hypoplasia in the BM and increased numbers of hematopoietic stem cells (HSCs). These effects of MSC‐EVs were mediated by T cell suppression and inhibition of interferon‐gamma (IFN‐γ) and tumor necrosis factor‐alpha (TNF‐α) production in the AA mouse model. In addition, an in vitro study revealed that MSC‐EVs led to reduced IFN‐γ and TNF‐α levels and there was an association with decreased splenocyte viability. Previous studies examined the diagnostic and prognostic values of microRNAs (miRNAs) in AA and identified miR‐199a, miR‐146a, miR‐223, and miR‐126. We used quantitative real‐time PCR to evaluate the expression of these miRNAs on isolated BM mononuclear cells (BM‐MNCs) from treated and untreated AA mice. miR‐223, miR‐146a, and miR‐199a expressions increased in the MSC‐EVs treated AA mice. Treatment with MSC‐EVs increased expression of miR‐223 and miR‐146a. Our findings showed that treatment with MSC‐EVs significantly ameliorated immune destruction of HSCs in the AA mouse model and confirmed the importance of miRNAs in the clinical status of this model.

Mesenchymal Stem Cell‐Derived Extracellular Vesicles with High PD‐L1 Expression for Autoimmune Diseases Treatment

“…The MSC‐derived extracellular vesicles were then isolated and purified according to an established protocol. [ 24 ] Transmission electron microscopy (TEM) imaging showed spherical morphology of MSC‐sEVs (Figure 2D) with an average diameter around 100 nm (Figure 2E), which had no significant difference compared to MSC‐sEVs‐PD‐L1. They contained extracellular vesicles‐associated proteins, e.g., CD63, CD9, and MSCs specific marker CD73 (Figure 2F).…”

Extracellular Vesicles of Mesenchymal Stem Cells: Therapeutic Properties Discovered with Extraordinary Success

“…As far as the mechanisms, MSC-EV immunomodulation is governed by proteins, including growth factors, interleukins, and also miRNAs, such as miR-21-5p, miR-223, miR-146a and miR-199a, whose expression is increased [45,49,50]. In a mouse model, treatment with MSC-EVs ameliorated significantly the immune destructions and confirmed the importance of the non-coding miRNAs also in the clinical developments [50]. Other treatments exacerbate various aspects of neuropathology.…”

“…The use of MSC-EVs for therapy of diseases has become relevant in many cases including encephalomyelitis and multiple sclerosis of the brain. The same vesicles also provide more potent therapeutic strategies for other immune-related disorders [50,52,53].…”

“…The form often employed to strengthen the early development of clinical practice is regenerative medicine, based on the EV-dependent regeneration of affected tissues such as the systems of brain, blood vessels and others [28,50,64,71,72,[107][108][109][110]. Critical for these processes, operative by cell-free strategy, is the successful translation of preclinical studies into clinical platforms [21,32,45].…”

Mesenchymal stromal cell-derived extracellular vesicles: novel approach in hematopoietic stem cell transplantation

“…Gholampour et.al report manifested that MSC‐EVs improve BM deficiency and attenuate AA development by modifying immune responses in a mouse model of AA. They revealed that miR‐126a, miR‐146a, miR199a, and miR‐223 in MSC‐EVs have an inhibitory activity on the proliferation of T cells, as well as the IFN‐γ and TNF‐α cytokine expressions [ 90 ].…”