In vitro naive CD4+ T cell differentiation upon treatment with miR-29b-loaded exosomes from mesenchymal stem cells

BACKGROUND

Gene regulation by microRNA (miRNA) is central in T lymphocytes differentiation processes. Here, we investigate miRNA-29b (miR-29b) roles in the reprogramming of T cell differentiation, which can be a promising therapeutic avenue for various types of inflammatory disorders such as rheumatoid arthritis and multiple sclerosis.

METHODS AND RESULTS

Adipose Mesenchymal Stem Cell-derived exosomes (AMSC-Exo) enriched with miR-29b were delivered into naive CD4+ T (nCD4+) cells. The expression level of important transcription factors including RAR-related orphan receptor gamma (RORγt), GATA3 binding protein (GATA3), T-box transcription factor 21, and Forkhead box P3 was determined by quantitative Real-Time PCR. Moreover, flow cytometry and Enzyme-linked Immunosorbent Assay were respectively used to measure the frequency of T regulatory cells and the levels of cytokines production (Interleukin 17, Interleukin 4, Interferon-gamma, and transforming growth factor beta. This study indicates that the transfection of miR-29b mimics into T lymphocytes through AMSC-Exo can alter the CD4+ T cells' differentiation into other types of T cells.

CONCLUSIONS

In conclusion, AMSC-Exo-based delivery of miR-29b can be considered as a new fascinating avenue for T cell differentiation inhibition and the future treatment of several inflammatory disorders.

Inhibition of miR-34a reduces cellular senescence in human adipose tissue-derived mesenchymal stem cells through the activation of SIRT1

AIMS

Human adipose derived mesenchymal stem cells (hAD-MSCs) as the most promising target for cell therapy and regenerative medicine, face senescence as a major drawback resulting in their limited proliferation and differentiation potentials. To evaluate the efficacy of miR-34a silencing as an anti-senescence strategy in hAD-MSCs, in this study common hallmarks of senescence were assessed after transient inhibition of miR-34a in hAD-MSCs.

MATERIALS AND METHODS

The expression levels of miR-34a in hAD-MSCs at different passages were evaluated by real-time quantitative PCR. hAD-MSCs at passage 2 and passage 7 were transfected with miR-34a inhibitor. Doubling time assay, colony forming assay, and cell cycle analysis were performed to evaluate cell proliferation rate. The activity of senescence associated β-galactosidase (SA-β-gal) was assessed by histochemical staining. Moreover, the senescence associated molecular alterations including that of pro-senescence (P53, P21 and P16) and anti-senescence (SIRT1, HTERT and CD44) genes were examined by quantitative RT-PCR and western blot assays. To evaluate the differentiation potentials of MSCs, following adipogenic and osteogenic induction, the expression levels of lineage specific markers were analyzed by qPCR.

KEY FINDINGS

Our results showed that inhibition of miR-34a enhances the proliferation, promotes the adipogenic and osteogenic differentiation potency, reduces the senescence associated-β gal activity, and reverses the senescence associated molecular alterations in hAD-MSCs.

SIGNIFICANCE

In this study, we showed that inhibition of miR-34a reduces the cellular senescence through the activation of SIRT1. Our findings support the silencing of miR-34a as an anti-senescence approach to improve the therapeutic potentials of hAD-MSCs.

Rn7SK small nuclear RNA is involved in cellular senescence

Rn7SK is a conserved small nuclear noncoding RNA which its function in aging has not been studied. Recently, we have demonstrated that Rn7SK overexpression reduces cell viability and is significantly downregulated in stem cells, human tumor tissues, and cell lines. In this study, we analyzed the role of Rn7SK on senescence in adipose tissue-derived mesenchymal stem cells (AD-MSCs). For this purpose, Rn7SK expression was downregulated and upregulated via transfection and transduction, respectively, in AD-MSCs and subsequently, various distinct characteristics of senescence including cell viability, proliferation, colony formation, senescence-associated β galactosidase activity, and differentiation potency was analyzed. Our results demonstrated the transient knockdown of Rn7SK in MSCs leads to delayed senescence, while its overexpressions shows opposite effects. When osteogenic differentiation was started, however, they exhibited a greater differentiation potential than the original MSCs, suggesting a potential tool for stem cell-based regenerative medicine.

A simple and highly efficient method for transduction of human adipose-derived mesenchymal stem cells

Mesenchymal stem cells (MSCs) are multipotent cells capable of differentiating into a wide range of cell types and provide a potential to transfer therapeutic protein in vivo, making them valuable candidates for gene therapy and cell therapy. However, using MSCs in in vivo is limited due to the low rate of transfection and transduction efficacy. Therefore, developing methods to efficiently transfer genes into MSCs would provide a number of opportunities for using them in the clinic. Here, we introduce a simple and robust method for efficient transduction of human adipose-derived MSCs by modification under the culture condition of human embryonic kidney cells 293 (HEK293T) and MSCs. Moreover, as a transduction enhancer, polybrene was replaced with Lipofectamine, a cationic lipid. Therefore, we showed that transduction of primary cells can be increased efficiently by modifying the culture condition.