Blockade of senescence‐associated micro RNA ‐195 in aged skeletal muscle cells facilitates reprogramming to produce induced pluripotent stem cells.

Abstract

SummaryThe low reprogramming efficiency in cells from elderly patients is a challenge that must be overcome. Recently, it has been reported that senescence‐associated microRNA (miR)‐195 targets Sirtuin 1 (SIRT1) to advance cellular senescence. Thus, we hypothesized that a blockade of miR‐195 expression could improve reprogramming efficiency in old skeletal myoblasts (SkMs). We found that miR‐195 expression was significantly higher in old SkMs (24 months) isolated from C57BL/6 mice as compared to young SkMs (2 months, 2.3‐fold). Expression of SIRT1 and telomerase reverse transcriptase (TERT) was downregulated in old SkMs, and transduction of old SkMs with lentiviral miR‐195 inhibitor significantly restored their expression. Furthermore, quantitative in situ hybridization analysis demonstrated significant telomere elongation in old SkMs transduced with anti‐miR‐195 (1.7‐fold increase). It is important to note that blocking miR‐195 expression markedly increased the reprogramming efficiency of old SkMs as compared to scramble (2.2‐fold increase). Transduction of anti‐miR‐195 did not alter karyotype or pluripotency marker expression. Induced pluripotent stem cells (iPSCs) from old SkMs transduced with anti‐miR‐195 successfully formed embryoid bodies that spontaneously differentiated into three germ layers, indicating that deletion of miR‐195 does not affect pluripotency in transformed SkMs. In conclusion, this study provided novel evidence that the blockade of age‐induced miR‐195 is a promising approach for efficient iPSC generation from aging donor subjects, which has the potential for autologous transplantation of iPSCs in elderly patients.

Mir-195: Roadblock for Reprogramming Aged Cells

“…MicroRNA (miR) microarray analysis has been used to identify miR-195 as a senescence-associated factor mediating aged mesenchymal stem cells [7]. Kondo et al recently demonstrated that miR-195 acts as a barrier for reprogramming skeletal muscles (skMs) from old mice [8]. Expression levels of miR-195 were significantly upregulated in old skMs (2.3-fold at 24-months) as compared to cells from young mice (2-months) using RT-PCR and in situ hybridization.…”

“…Expression levels of miR-195 were significantly upregulated in old skMs (2.3-fold at 24-months) as compared to cells from young mice (2-months) using RT-PCR and in situ hybridization. Proteins linked to the senescence pathways (i.e., P53, P21, and P16) were activated in SkMs obtained from old mice, and the characteristics of cellular senescence were demonstrated by β-galactosidase staining and telomere length reduction [8].…”

“…skMs also become resistant to reprogramming as they age, and miR-195 is significantly decreased in iPSCs derived from old skMs [8], indicating that miR-195 is a negative mediator of iPSC reprogramming. Kondo MicroRNAs are post-transcriptional gene regulators in cells and can be manipulated to provide a better understanding of specific factors that alter aging signalling pathways during cellular reprogramming [9].…”

Inflamma-miRs in Aging and Breast Cancer: Are They Reliable Players?

“…The abrogation of the miR-195 expression is a promising therapy in elderly patients. Therefore, miR-195 could serve as an inflammatory biomarker in ARDs ( 105 , 106 ). Based on the finding that certain miRNAs decreased tumorigenesis, and it was proposed that the coordinated action of upregulated-senescence inflamma-miRs could block cancerous cell growth by reducing oncogenes and tumor promoters’ levels.…”

“…It is generally accepted that the main sources of circulating inflamma-miRs in aging and ARDs are immunity circulating/tissue cells and endothelial circulating/resident cells. Inflammatory stimulation and cell senescence can induce and perpetuate systemic inflammation over time, by inducing the upregulation of inflamma-miRs through the excessive activation of inflammatory pathways ( 109 , 112 ) [Table 4 ; ( 105 , 106 , 109 – 112 )].…”