Changes in PTTG1 by human TERT gene expression modulate the self-renewal of placenta-derived mesenchymal stem cells

Abstract

In addition to their differentiation potential, self-renewal capability is an important characteristic of stem cells. The limited self-renewal activity of mesenchymal stem cells is the greatest obstacle to the application of stem cell therapy in regenerative medicine. The human TERT gene enhances the self-renewal of MSCs, but the mechanism of self-renewal and the interactions among TERT-gene-related molecules remain unknown. The objectives of this study were to generate immortalized MSCs derived from MSCs isolated from placenta (naive) by human TERT gene transfection with the AMAXA gene delivery system, to compare their characteristics, and to investigate whether increased TERT expression affected the pituitary tumor transforming gene (PTTG1; also known as securin), which is involved in chromosome segregation during mitosis. TERT-immortalized cells (TERT+) with a prolonged life span displayed high PTTG1 expression. TERT+ cells also retained the stemness capacity and multipotency of naive cells and displayed high PTTG1 expression. However, down-regulation of PTTG1 by treatment with short interfering RNA induced cell senescence and decreased telomerase activity. Moreover, TERT bound to PTTG1 formed complexes with chaperones such as Ku70 and heat shock protein 90. Thus, placental MSCs immortalized by TERT gene transfection display differentiation potential and exhibit enhanced self-renewal through a balanced interaction of PTTG1 and chaperones. The interaction between TERT and PTTG1 by association of Ku70 might be important for the enhancement of the limited self-renewal activity of MSCs and for understanding the regulatory mechanisms of self-renewal.

Improved therapeutics of modified mesenchymal stem cells: an update

“…Again, telomerase reverse transcriptase (TERT) transfected MSCs were reported to hinder senescence and possess higher proliferative and cell cycle-related gene expression factors [72], and as well enhanced neural and osteogenic lineages proliferation [73,74]. Some of the interactions known to underlie the mechanism of the human TERT gene enhancing the self-renewal ability of MSCs (and averting cellular senescence) include the complex formation with molecules such as securin, heat shock protein 90 and chaperones such as Ku70 [72]. Signaling pathways involved in the modulatory functions of TERT gene to enhance osteoblast differentiation of human bone marrow-derived MSCs include insulin-like growth factor (IGF) signaling.…”

Functionally enhanced placenta-derived mesenchymal stem cells inhibit adipogenesis in orbital fibroblasts with Graves’ ophthalmopathy

“…Especially, AMAXA technique provides critical opportunities for hard-to-transfect primary cell line including MSCs. In our previous study, we generated TERT-overexpressing PD-MSCs using a nonviral AMAXA system to study the underlying regulatory mechanisms of self-renewal [27]. In addition, PD-MSC PRL-1 transplantation in hepatic failure model indicated therapeutic effects including anti-brotic and proliferative potentials compared to naïve PD-MSCs [28].…”

Functionally enhanced placenta-derived mesenchymal stem cells inhibit adipogenesis in orbital fibroblasts with Graves’ ophthalmopathy

“…Especially, AMAXA technique provides critical opportunities for hard-to-transfect primary cell line including MSCs. In our previous study, we generated TERT-overexpressing PD-MSCs using a nonviral AMAXA system to study the underlying regulatory mechanisms of self-renewal [28]. In addition, PD-MSC PRL-1 transplantation in hepatic failure model indicated therapeutic effects including anti-brotic and proliferative potentials compared to naïve PD-MSCs [29].…”