Telomerase reactivation reverses tissue degeneration in aged telomerase-deficient mice

Journal name:
Date published:
Published online

An ageing world population has fuelled interest in regenerative remedies that may stem declining organ function and maintain fitness. Unanswered is whether elimination of intrinsic instigators driving age-associated degeneration can reverse, as opposed to simply arrest, various afflictions of the aged. Such instigators include progressively damaged genomes. Telomerase-deficient mice have served as a model system to study the adverse cellular and organismal consequences of wide-spread endogenous DNA damage signalling activation in vivo1. Telomere loss and uncapping provokes progressive tissue atrophy, stem cell depletion, organ system failure and impaired tissue injury responses1. Here, we sought to determine whether entrenched multi-system degeneration in adult mice with severe telomere dysfunction can be halted or possibly reversed by reactivation of endogenous telomerase activity. To this end, we engineered a knock-in allele encoding a 4-hydroxytamoxifen (4-OHT)-inducible telomerase reverse transcriptase-oestrogen receptor (TERT-ER) under transcriptional control of the endogenous TERT promoter. Homozygous TERT-ER mice have short dysfunctional telomeres and sustain increased DNA damage signalling and classical degenerative phenotypes upon successive generational matings and advancing age. Telomerase reactivation in such late generation TERT-ER mice extends telomeres, reduces DNA damage signalling and associated cellular checkpoint responses, allows resumption of proliferation in quiescent cultures, and eliminates degenerative phenotypes across multiple organs including testes, spleens and intestines. Notably, somatic telomerase reactivation reversed neurodegeneration with restoration of proliferating Sox2+ neural progenitors, Dcx+ newborn neurons, and Olig2+ oligodendrocyte populations. Consistent with the integral role of subventricular zone neural progenitors in generation and maintenance of olfactory bulb interneurons2, this wave of telomerase-dependent neurogenesis resulted in alleviation of hyposmia and recovery of innate olfactory avoidance responses. Accumulating evidence implicating telomere damage as a driver of age-associated organ decline and disease risk1, 3 and the marked reversal of systemic degenerative phenotypes in adult mice observed here support the development of regenerative strategies designed to restore telomere integrity.

At a glance


  1. 4-OHT-dependent induction of telomerase activity in TERT-ER cells.
    Figure 1: 4-OHT-dependent induction of telomerase activity in TERT-ER cells.

    a, Telomerase activity in eNSCs (*, telomerase products) (top); real-time quantification of reactions above (bottom). b, Representative G4TERT-ER splenocyte metaphases. c, Proliferation of adult G4TERT-ER fibroblasts (n = 3) in media with vehicle (black) or 4-OHT (red). d, Representative image of G4TERT-ER fibroblasts (passage 6) in media with 4-OHT (bottom) or vehicle (top). e, Signal-free ends in primary splenocyte metaphases, 15 metaphases per sample, n = 2 (*P<0.05). f, Mean telomere-FISH signal in primary splenocyte interphases, normalized to centromeric signal, n = 3 (***P<0.0001). Open bars correspond to vehicle-treated and filled bars to 4-OHT-treated, error bars represent s.d.

  2. Telomerase activation in adult TERT-ER mice.
    Figure 2: Telomerase activation in adult TERT-ER mice.

    ac, Representative images of tissues from experimental and control mice. a, Haematoxylin and eosin-stained sections of testes. b, Primary splenocytes stained for 53BP1. c, Small intestine sections stained for 53BP1. d, Testes weight of adult males (30–50-week-old, n10). e, 53BP1 nuclear foci per 100 nuclei (n = 3). f, 53BP1 nuclear foci per 100 crypts (n = 4). g, Litter sizes (n = 3); h, Spleen weights (n6). i, Apoptotic cells per 100 intestinal crypts (n20). ***P = 0.0001, **P<0.005, *P<0.05. Open bars correspond to vehicle-treated and filled bars to 4-OHT-treated groups, error bars represent s.d.

  3. Neural stem cell function following telomerase reactivation in vitro.
    Figure 3: Neural stem cell function following telomerase reactivation in vitro.

    ac, Representative images of experimental and control mice-derived NSCs. a, Secondary neurospheres. b, Differentiated NSCs stained with 53BP1 or c, GFAP and TUJ1 antibodies. d, Self-renewal capacity of secondary neurospheres (n = 4) ***P<0.0001, *P<0.001. e, 53BP1 nuclear foci per 100 cells (>400 nuclei per culture, n = 3). f, Multipotency (GFAP+/TUJ1+) of NSCs (n = 4; 308 wells per culture condition) **P = 0.0066. Scale bar, 100μm. Open bars correspond to vehicle-treated and filled bars to 4-OHT-treated groups, error bars represent s.d.

  4. NSC proliferation and differentiation following telomerase reactivation in vivo.
    Figure 4: NSC proliferation and differentiation following telomerase reactivation in vivo.

    NSC proliferation and neurogenesis were measured by Ki67, Sox-2 and Dcx expression in SVZ from experimental and control mice. Mature oligodendrocytes in the corpus callosum were stained with anti-Olig2 antibody. Equivalent coronal sections (n>10) were scored in a blinded fashion by laser scanning and plotted on the right panels. ×20 (SVZ) or ×40 (corpus callosum) objectives were used. *** P<0.0001, **P = 0.0022. Open bars correspond to vehicle-treated and filled bars to 4-OHT-treated groups, error bars represent s.d.

  5. Brain size, myelination, and olfactory function following telomerase reactivation.
    Figure 5: Brain size, myelination, and olfactory function following telomerase reactivation.

    a, Representative brains from age-matched experimental and control animals. b, Brain weights, n10, ***P = 0.0004, *P = 0.02. c, Representative electron micrographs of myelinated axonal tracts in corpus callosum, arrow heads indicate myelin sheath width (×12,000). Scale bars, 200nm. d, g ratios (inner/outer radii) (n = 2, >150 axons per mouse) ***P<0.0001. e, Representative tracings of experimental and control mice during 3-min exposure to water or 2-MB. f, g, Time spent in scent zone 3 with water or 2-MB for vehicle- or 4-OHT-treated G0TERT-ER (squares) and G4TERT-ER (circles) mice; n = 4. Error bars represent s.d., except in (d) (s.e.m.).


  1. Sahin, E. & Depinho, R. A. Linking functional decline of telomeres, mitochondria and stem cells during ageing. Nature 464, 520528 (2010)
  2. Whitman, M. C. & Greer, C. A. Adult neurogenesis and the olfactory system. Prog. Neurobiol. 89, 162175 (2009)
  3. Sharpless, N. E. & DePinho, R. A. How stem cells age and why this makes us grow old. Nature Rev. Mol. Cell Biol. 8, 703713 (2007)
  4. Ju, Z. & Lenhard Rudolph, K. Telomere dysfunction and stem cell ageing. Biochimie 90, 2432 (2008)
  5. Hoeijmakers, J. H. DNA damage, aging, and cancer. N. Engl. J. Med. 361, 14751485 (2009)
  6. Ferrón, S. et al. Telomere shortening and chromosomal instability abrogates proliferation of adult but not embryonic neural stem cells. Development 131, 40594070 (2004)
  7. Cawthon, R. M. et al. Association between telomere length in blood and mortality in people aged 60 years or older. Lancet 361, 393395 (2003)
  8. Wyllie, F. S. et al. Telomerase prevents the accelerated cell ageing of Werner syndrome fibroblasts. Nature Genet. 24, 1617 (2000)
  9. Bodnar, A. G. et al. Extension of life-span by introduction of telomerase into normal human cells. Science 279, 349352 (1998)
  10. Tomás-Loba, A. et al. Telomerase reverse transcriptase delays aging in cancer-resistant mice. Cell 135, 609622 (2008)
  11. Samper, E., Flores, J. M. & Blasco, M. A. Restoration of telomerase activity rescues chromosomal instability and premature aging in Terc−/− mice with short telomeres. EMBO Rep. 2, 800807 (2001)
  12. Metzger, D. et al. Conditional site-specific recombination in mammalian cells using a ligand-dependent chimeric Cre recombinase. Proc. Natl Acad. Sci. USA 92, 69916995 (1995)
  13. Blasco, M. A. et al. Telomere shortening and tumor formation by mouse cells lacking telomerase RNA. Cell 91, 2534 (1997)
  14. Wong, K. K. et al. Telomere dysfunction and Atm deficiency compromises organ homeostasis and accelerates ageing. Nature 421, 643648 (2003)
  15. Choudhury, A. R. et al. Cdkn1a deletion improves stem cell function and lifespan of mice with dysfunctional telomeres without accelerating cancer formation. Nature Genet. 39, 99105 (2006)
  16. Best, B. P. Nuclear DNA damage as a direct cause of aging. Rejuvenation Res. 12, 199208 (2009)
  17. Drapeau, E. & Nora Abrous, D. Stem cell review series: role of neurogenesis in age-related memory disorders. Aging Cell 7, 569589 (2008)
  18. Ferrón, S. R. et al. Telomere shortening in neural stem cells disrupts neuronal differentiation and neuritogenesis. J. Neurosci. 29, 1439414407 (2009)
  19. Enwere, E. et al. Aging results in reduced epidermal growth factor receptor signaling, diminished olfactory neurogenesis, and deficits in fine olfactory discrimination. J. Neurosci. 24, 83548365 (2004)
  20. Lafreniere, D. & Mann, N. Anosmia: loss of smell in the elderly. Otolaryngol. Clin. North Am. 42, 123131 (2009)
  21. Ma, D. K. et al. Activity-dependent extrinsic regulation of adult olfactory bulb and hippocampal neurogenesis. Ann. NY Acad. Sci. 1170, 664673 (2009)
  22. Kobayakawa, K. et al. Innate versus learned odour processing in the mouse olfactory bulb. Nature 450, 503508 (2007)
  23. Caporaso, G. L. et al. Telomerase activity in the subventricular zone of adult mice. Mol. Cell. Neurosci. 23, 693702 (2003)
  24. Artandi, S. E. & DePinho, R. A. Telomeres and telomerase in cancer. Carcinogenesis 31, 918 (2010)
  25. Zhang, P., Dilley, C. & Mattson, M. P. DNA damage responses in neural cells: focus on the telomere. Neuroscience 145, 14391448 (2007)
  26. Lee, J. et al. Telomerase deficiency affects normal brain functions in mice. Neurochem. Res. 35, 211218 (2010)
  27. Breton-Provencher, V. et al. Interneurons produced in adulthood are required for the normal functioning of the olfactory bulb network and for the execution of selected olfactory behaviors. J. Neurosci. 29, 1524515257 (2009)
  28. Maser, R. S. et al. DNA-dependent protein kinase catalytic subunit is not required for dysfunctional telomere fusion and checkpoint response in the telomerase-deficient mouse. Mol. Cell. Biol. 27, 22532265 (2007)
  29. Abramoff, M. D., Magelhaes, P. J. & Ram, S. J. Image Processing with ImageJ. Biophotonics Int. 11, 3642 (2001)
  30. Potzner, M. R. et al. Prolonged Sox4 expression in oligodendrocytes interferes with normal myelination in the central nervous system. Mol. Cell. Biol. 27, 53165326 (2007)
  31. Shao, C. et al. Mitotic recombination produces the majority of recessive fibroblast variants in heterozygous mice. Proc. Natl Acad. Sci. USA 96, 92309235 (1999)
  32. Paik, J. H. et al. FoxOs cooperatively regulate diverse pathways governing neural stem cell homeostasis. Cell Stem Cell 5, 540553 (2009)
  33. Mahoney, J. E. et al. Quantification of telomere length by FISH and laser scanning cytometry. Proc. SPIE 6859, 19 (2008)
  34. Gorczyca, W. et al. Analysis of human tumors by laser scanning cytometry. Methods Cell Biol. 64, 421443 (2001)
  35. Spink, A. J. et al. The EthoVision video tracking system–a tool for behavioral phenotyping of transgenic mice. Physiol. Behav. 73, 731744 (2001)

Download references

Author information


  1. Belfer Institute for Applied Cancer Science and Departments of Medical Oncology, Medicine and Genetics, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA

    • Mariela Jaskelioff,
    • Florian L. Muller,
    • Ji-Hye Paik,
    • Emily Thomas,
    • Shan Jiang,
    • Ergun Sahin,
    • Maria Kost-Alimova,
    • Alexei Protopopov,
    • Juan Cadiñanos,
    • James W. Horner &
    • Ronald A. DePinho
  2. Division of Endocrinology, Diabetes & Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA

    • Andrew C. Adams &
    • Eleftheria Maratos-Flier


M.J. and R.A.D. designed and guided the research; M.J., F.L.M., J.-H.P., E.S., E.T., S.J. and M.K.-A. performed research. J.C. and J.W.H. generated the TERT-ER mouse. M.J., F.L.M., A.C.A., A.P., E.M.-F. and R.A.D. analysed data. M.J. and R.A.D. wrote the manuscript.

Competing financial interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to:

Author details

Supplementary information

PDF files

  1. Supplementary Information (751K)

    This file contains Supplementary Figures 1-4 with legends and Supplementary Tables 1-3.


  1. Report this comment #17235

    Rob Ord said:

    I believe that Robin Holiday (who also established the mechanism for DNA recombination) first proposed the 'loss-of chormosome'/ telomere model in a 1974 Fed. Proc. article, yet I never see him recognised. Is it now appropriate that he be recognised for his seminal contribution?

    Rob Ord PhD, LLB
    70 Russell St, Nelson 7010, New Zealand

Subscribe to comments

Additional data