Telomerase enhances osteogenic ifferentiation of sheep bone marrow mesenchymal stem cells (BMSCs) by up-regulating PI3K/Akt pathway in vitro

Telomerase reverse transcriptase (TERT) vectors were transfected into bone marrow mesen- chymal stem cells (BMSCs) which were then cultured and selected to establish TERT-BMSC cell lines whilst sequencing BMSCs and TERT-BMSCs via transcriptome in this study to explore their regulatory mechanism and effect on osteogenic differentiation after TERT ectopic expres- sion in sheep BMSCs. After sequencing and analysing differential genes, PI3K/Akt signalling pathway related to osteogenic differentiation was investigated. Western blot was used before and after applying the PI3K/Akt signalling pathway inhibitor LY294002 to detect protein expression levels of AKT and p-AKT. On the twenty-first day of osteogenic differentiation, RT-qPCR and Western blot were used to detect mRNA and protein expression levels of RUNX2 and OPN and alizarin red staining was utilised to analyse calcium salt deposition. Results showed that pro- tein expression levels of AKT and p-AKT were significantly up-regulated, mRNA and protein expression levels of RUNX2 and OPN increased and calcium salt deposition increased after ectopic expression of TERT. After applying LY294002, the protein expression of AKT and p-AKT was down-regulated, mRNA and protein expression levels of RUNX2 and OPN were reduced and calcium salt deposition was reduced. These results confirmed the stable integration and expression of the exogenous TERT gene in BMSCs to promote the differentiation of BMSC osteoblasts, which may be mediated by the PI3K/Akt signalling pathway.