MicroRNA-based system in stem cell reprogramming; differentiation/dedifferentiation

MicroRNA‑124: an emerging therapeutic target in central nervous system disorders

The central nervous system (CNS) consists of neuron and non-neuron cells including neural stem/precursor cells (NSPCs), neuroblasts, glia cells (mainly astrocyte, oligodendroglia and microglia), which thereby form a precise and complicated network and exert diverse functions through interactions of numerous bioactive ingredients. MicroRNAs (miRNAs), with small size approximately  ~ 21nt and as well-documented post-transcriptional key regulators of gene expression, are a cluster of evolutionarily conserved endogenous non-coding RNAs. More than 2000 different miRNAs has been discovered till now. MicroRNA-124(miR-124), the most brain-rich microRNA, has been validated to possess important functions in the central nervous system, including neural stem cell proliferation and differentiation, cell fate determination, neuron migration, synapse plasticity and cognition, cell apoptosis etc. According to recent studies, herein, we provide a review of this conversant miR-124 to further understand the potential functions and therapeutic and clinical value in brain diseases.

MiR-106b-5p Regulates the Reprogramming of Spermatogonial Stem Cells into iPSC (Induced Pluripotent Stem Cell)-Like Cells

Background:

Recent years have brought notable progress in raising the efficiency of the reprogramming technique so that approaches have evolved from known transgenic factors to only a few miRNAs. Nevertheless, there is a poor understanding of both the key factors and biological networks underlying this reprogramming. The present study aimed to investigate the potential of miR-106b-5p in regulating SSCs to iPSC-like cells.

Methods:

We used SSCs because pluripotency is inducible in SSCs under defined culture conditions, and they have a few issues compared to other adult stem cells. As both signaling and post-transcriptional gene controls are critical for pluripotency regulation, we traced the expression of OSKMN. Besides, we considered miR-106b-5p targets using bioinformatic methods.

Results:

Our results showed that transfected SSCs with miR-106b-5p increased the expression of the OSKMN factors, which was significantly more than negative control groups. Moreover, using the functional miRNA enrichment analysis, online tools, and databases, we predicted that miR-106b-5p targeted a signaling pathway gene named MAPK1/ERK2, related to regulating stem cell pluripotency.

Conclusion:

Together, our data suggest that miR-106b-5p regulates the reprogramming of SSCs into iPSC-like cells. Furthermore, noteworthy progress in the in vitro development of SSCs indicates promise reservoirs and opportunities for future clinical trials.

Inter-regulatory role of microRNAs in interaction between viruses and stem cells

MicroRNAs (miRNAs) are well known for post-transcriptional regulatory ability over specific mRNA targets. miRNAs exhibit temporal or tissue-specific expression patterns and regulate the cell and tissue developmental pathways. They also have determinative roles in production and differentiation of multiple lineages of stem cells and might have therapeutic advantages. miRNAs are a part of some viruses’ regulatory machinery, not a byproduct. The trace of miRNAs was detected in the genomes of viruses and regulation of cell reprograming and viral pathogenesis. Combination of inter-regulatory systems has been detected for miRNAs during viral infections in stem cells. Contraction between viruses and stem cells may be helpful in therapeutic tactics, pathogenesis, controlling viral infections and defining stem cell developmental strategies that is programmed by miRNAs as a tool. Therefore, in this review we intended to study the inter-regulatory role of miRNAs in the interaction between viruses and stem cells and tried to explain the advantages of miRNA regulatory potentials, which make a new landscape for future studies.

MiR-155-5p modulates HSV-1 replication via the epigenetic regulation of SRSF2 gene expression

A previous study reported that miR-155-5p knockout mice were more resistant to herpes simplex virus type I (HSV-1) infection. However, the exact underlying molecular mechanism remains to be elucidated. Here, we demonstrated that HSV-1 infection upregulates miR-155-5p expression. By binding to the promoter of serine/arginine-rich splicing factor 2 (SRSF2), which is an important transcriptional activator of HSV-1 genes that was previously reported by our group, and altering the histone modification located near the transcription start site (TSS) of the SRSF2 gene, miR-155-5p promotes the transcription of the SRSF2 gene, ultimately increasing viral replication and viral gene expression. Our results provide insight for an understanding of the roles and molecular mechanism of miR-155-5p in HSV-1 replication and the epigenetic control of SRSF2 gene expression.

Ectopic microRNAs used to preserve human mesenchymal stem cell potency and epigenetics

Human mesenchymal stem cells (hMSCs) have remarkable potential for use in regenerative medicine. However, one of the great challenges is preserving their potency for long time. This study investigated the effect of miRNA ectopic expression on their proliferation and also on the expression level of Parp1 as an epigenetic switch preserving pluripotency in hMSCs. A cationic liposome was prepared as an efficient carrier for miRNA delivery. The miRNA loading efficiency and physical stability of vesicles were measured, and their scanning electron microscopic shapes determined. hMSCs were transfected with miR-302a and miR-34a followed by assessment of their proliferation potency with MTT assay and measurement of the expression of Parp1 by quantitative polymerase chain reaction (QPCR). Cell transfection with miR-302a and miR-34a efficiently and differentially affects the proliferation potency of hMSCs and the expression level of Parp1 as the key epigenetic factor involved in pluripotency. While miR-302a increases Parp1 expression, miR-34a suppresses it significantly, showing differential effects. Our results demonstrated that miRNA-based treatments represent efficient therapeutic systems and hold a great promise for future use in regenerative medicine through modification of hMSC pluripotency and epigenome.

miR‑15a represses cancer cell migration and invasion under conditions of hypoxia by targeting and downregulating Bcl‑2 expression in human osteosarcoma cells

Osteosarcoma is a common, high-risk primary bone malignancy that mostly affects the younger population. There has been no marked improvement in the clinical outcomes of osteosarcoma patients to date, and cancer recurrence and metastasis are common in high-grade osteosarcoma. Therefore, identifying new biomarkers and novel therapeutic targets is crucial for improving the prognosis of osteosarcoma patients. In the present study, the MG63 human osteosarcoma cell line was employed to examine the role of microRNA (miR)-15a in regulating cellular activities under hypoxic conditions. It was demonstrated that hypoxia stimulates migration and invasion in MG63 cells, which was correlated with the downregulation of miR-15a and upregulation of B-cell lymphoma 2 (Bcl-2) expression. Introduction of miR-15a or knockdown of endogenous Bcl-2 may reduce hypoxia-induced cell invasion and migration through the regulation of matrix metalloproteinases. Analysis of the expression of miR-15a indicated that hypoxia repressed the transcription of deleted in lymphocytic leukemia 2 (DLEU2), which is the host gene of miR-15a. These findings indicated that miR-15a may be a valuable target for the treatment of osteosarcoma, particularly for patients with high-grade cancer or heavy tumor burden.

Non-coding RNAs are promising targets for stem cell-based cancer therapy

The term “non-coding RNA” (ncRNA) is generally used to indicate RNA that does not encode a protein and includes several classes of RNAs, such as microRNA and long non-coding RNA. Several lines of evidence suggest that ncRNAs appear to be involved in a hidden layer of biological procedures that control various levels of gene expression in physiology and development including stem cell biology. Stem cells have recently constituted a revolution in regenerative medicine by providing the possibility of generating suitable cell types for therapeutic use. Here, we review the recent progress that has been made in elaborating the interaction between ncRNAs and tissue/cancer stem cells, discuss related technical and biological challenges, and highlight plausible solutions to surmount these difficulties. This review particularly emphasises the involvement of ncRNAs in stem cell biology and in vivo modulation to treat and cure specific pathological disorders especially in cancer. We believe that a better understanding of the molecular machinery of ncRNAs as related to pluripotency, cellular reprogramming, and lineage-specific differentiation is essential for progress of cancer therapy.

Differential expression of conserved and novel microRNAs during tail regeneration in the lizard Anolis carolinensis

Background

Lizards are evolutionarily the most closely related vertebrates to humans that can lose and regrow an entire appendage. Regeneration in lizards involves differential expression of hundreds of genes that regulate wound healing, musculoskeletal development, hormonal response, and embryonic morphogenesis. While microRNAs are able to regulate large groups of genes, their role in lizard regeneration has not been investigated.

Results

MicroRNA sequencing of green anole lizard (Anolis carolinensis) regenerating tail and associated tissues revealed 350 putative novel and 196 known microRNA precursors. Eleven microRNAs were differentially expressed between the regenerating tail tip and base during maximum outgrowth (25 days post autotomy), including miR-133a, miR-133b, and miR-206, which have been reported to regulate regeneration and stem cell proliferation in other model systems. Three putative novel differentially expressed microRNAs were identified in the regenerating tail tip.

Conclusions

Differentially expressed microRNAs were identified in the regenerating lizard tail, including known regulators of stem cell proliferation. The identification of 3 putative novel microRNAs suggests that regulatory networks, either conserved in vertebrates and previously uncharacterized or specific to lizards, are involved in regeneration. These findings suggest that differential regulation of microRNAs may play a role in coordinating the timing and expression of hundreds of genes involved in regeneration.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-016-2640-3) contains supplementary material, which is available to authorized users.

MicroRNAs; easy and potent targets in optimizing therapeutic methods in reparative angiogenesis

The age‐related senescence of adult tissues is associated with the decreased level of angiogenic capability and with the development of a degenerative disease such as atherosclerosis which thereafter result in the deteriorating function of multiple systems. Findings indicate that tissue senescence not only diminishes repair processes but also promotes atherogenesis, serving as a double‐edged sword in the development and prognosis of ischaemia‐associated diseases. Evidence evokes microRNAs (miRNAs) as molecular switchers that underlie cellular events in different tissues. Here, miRNAs would promote new potential targets for optimizing therapeutic methods in blood flow recovery to the ischaemic area. Effectively beginning an ischaemia therapy, a more characteristic of miRNA changes in adult tissues is prerequisite and in the forefront. It may also be a preliminary phase in treatment strategies by stem cell‐based therapy.

MiR-15a and miR-16 induce autophagy and enhance chemosensitivity of Camptothecin

It has been reported that persistent or excessive autophagy promotes cancer cell death during chemotherapy, either by enhancing the induction of apoptosis or mediating autophagic cell death. Here, we show that miR-15a and miR-16 are potent inducers of autophagy. Rictor, a component of mTORC2 complex, is directly targeted by miR-15a/16. Overexpression of miR-15a/16 or depletion of endogenous Rictor attenuates the phosphorylation of mTORC1 and p70S6K, inhibits cell proliferation and G1/S cell cycle transition in human cervical carcinoma HeLa cells. Moreover, miR-15a/16 dramatically enhances anticancer drug camptothecin (CPT)-induced autophagy and apoptotic cell death in HeLa cells. Collectively, these data demonstrate that miR-15a/16 induced autophagy contribute partly to their inhibition of cell proliferation and enhanced chemotherapeutic efficacy of CPT.