“…However, telomerase, a ribonucleoprotein enzyme, can rebuild and restore telomere length, preventing or delaying cell senescence (Blackburn, 1999; Calado and Young, 2009). While undetectable in most normal somatic cells, telomerase remains active in certain replicating tissues, such as male germ cells and activated lymphocytes and in stem cells, including neural stem cells residing in the dentate gyrus of the hippocampus (HC) (Mattson and Klapper, 2001; Fu et al, 2002b; Cheng et al, 2007; Zhang et al, 2007; Wolkowitz et al, 2008; Jaskelioff et al, 2011; Zhou et al, 2011). Apart from its telomere-lengthening function, telomerase (or its catalytic enzyme component, telomerase reverse transcriptase; TERT) has certain non-canonical functions that are unrelated to telomere lengthening, including (in animal models) neurotrophic, cell survival-enhancing and “antidepressant-like” properties (Zhu et al, 2000; Mattson et al, 2001; Fu et al, 2002a; Fu et al, 2002b; Kang et al, 2004; Jaskelioff et al, 2011; Li et al, 2011; Niu and Yip, 2011; Zhou et al, 2011; Liu et al, 2012).…”