Transient delivery of modified mRNA encoding TERT rapidly extends telomeres in human cells

Abstract

Telomere extension has been proposed as a means to improve cell culture and tissue engineering and to treat disease. However, telomere extension by nonviral, nonintegrating methods remains inefficient. Here we report that delivery of modified mRNA encoding TERT to human fibroblasts and myoblasts increases telomerase activity transiently (24-48 h) and rapidly extends telomeres, after which telomeres resume shortening. Three successive transfections over a 4 d period extended telomeres up to 0.9 kb in a cell type-specific manner in fibroblasts and myoblasts and conferred an additional 28 6 1.5 and 3.4 6 0.4 population doublings (PDs), respectively. Proliferative capacity increased in a dose-dependent manner. The second and third transfections had less effect on proliferative capacity than the first, revealing a refractory period. However, the refractory period was transient as a later fourth transfection increased fibroblast proliferative capacity by an additional 15.2 6 1

Rapid Expansion of Human Epithelial Stem Cells Suitable for Airway Tissue Engineering

“…In addition, we found that telomerase signaling genes were affected by coculture. Although hTERT is not typically expressed in somatic cells, low expression levels are thought to slow telomere shortening in adult stem cells (56) and exogenous addition of hTERT mRNA extends telomeres and the life span of epidermal keratinocytes in vitro (57). The apparent stabilization of telomere length during 3T31Y culture supports our view that basal stem cells are better preserved.…”

A synopsis on aging—Theories, mechanisms and future prospects

“…If telomere extension can increase cell proliferative capacity in vitro (Ramunas et al, 2015) and account for the reversal of tissue degeneration in mice (Jaskelioff et al, 2011), than there is the possibility of being used to attenuate the rate of aging. That is certainly the core concept behind the commercialization, by some companies, of telomere measurement kits (Wolinsky, 2011), aimed at estimating the biological age of individuals and, to some extent, the risk of developing telomere shortening-associated diseases, such as atherosclerosis (Samani et al, 2001), coronary heart diseases (Ogami et al, 2004) and liver cirrhosis (Wiemann et al, 2002).…”

Trends in tissue repair and regeneration

“…Remarkably, telomere shortening occurs in the heart independently of cell division (Chang et al, 2016). Blau's laboratory has developed a transient modified mRNA approach to deliver TERT for only 48 h, which overcomes problems associated with constitutive retroviral delivery, and leads to a marked increase in telomere length and rescue of cell proliferative defects (Ramunas et al, 2015). Finally, Saul Villeda (UCSF, USA), who explores the mechanisms of brain ageing, used mouse parabiosis experiments to show that β2-microglobulin (B2M) is a brain ageing factor, the action of which is mediated by the MHC (Smith et al, 2015).…”