“Gene Therapy Mediated Partial Reprogramming Extends Lifespan and Reverses Age-Related Changes in Aged Mice”, Carolina Cano Macip, Rokib Hasan, Victoria Hoznek, Jihyun Kim, Louis E. Metzger, Saumil Sethna, Noah Davidsohn2023-01-05 (, )⁠:

[Twitter] Aging is a complex process best characterized as the chronic dysregulation of cellular processes leading to deteriorated tissue and organ function. While aging cannot currently be prevented, its impact on lifespan and healthspan in the elderly can potentially be minimized by interventions that aim to return these cellular processes to optimal function.

Recent studies have demonstrated that partial reprogramming using the Yamanaka factors (or a subset; OCT4, SOX2, and KLF4; OSK) can reverse age-related changes in vitro and in vivo. However, it is still unknown whether the Yamanaka factors (or a subset) are capable of extending the lifespan of aged wild type mice.

Here, we show that systemically delivered AAVs, encoding an inducible OSK system, in 124-week-old mice:

extends the median remaining lifespan by 109% over wild-type controls and enhances several health parameters. [Still less than rapamycin can do…] Importantly, we observed a statistically-significant improvement in frailty scores indicating that we were able to improve the healthspan along with increasing the lifespan. Furthermore, in human keratinocytes expressing exogenous OSK, we observed statistically-significant epigenetic markers of age-reversal, suggesting a potential reregulation of genetic networks to a younger, potentially healthier state.

Together, these results may have important implications for the development of partial reprogramming interventions to reverse age-associated diseases in the elderly.

Supplementary Figure 1: Overall survival proportion curves for control mice and TRE-OSK mice over the entire lifespan. Survival proportions for the whole time course for data shown in Figure 1.
Figure 1: Partial reprogramming with TRE-OSK leads to increased lifespan and improved frailty scores in very old mice. (a) Schematic of the constructs, virus, and injection route used in the study. (b) Kaplan-Meier curves for 124-week WT mice injected with AAV9.TRE-OSK and AAV9.hEF1?-rtTA4 (both 1E12 vg/animal) via the retro-orbital route, and induced with one week on/off doxycycline paradigm (TRE-OSK) showed median lifespan extension of remaining life by 109% compared to either doxycycline treated control animals (Control-Dox) or to historical published Jax data for Bl6/J mice (Jax historical). Red arrow indicates AAV injections. Mantel Cox Log rank test, ✱✱ <em>p</em> < 0.05. (c) Graph shows remaining lifespan of individual mice (after injections at week 124) for data shown in b. Two-tailed unpaired t-test; ✱✱ <em>p</em> < 0.05. (d) Frailty index (FI), the compound score of 28 different health parameters (range 0–1 in 0.5 increments), showed statistically-significant reduction in FI for TRE-OSK mice at 142 weeks of age (18 weeks after injections) as compared to Control-Dox mice. Student’s unpaired t-test, ✱✱ <em>p</em> < 0.05.
Figure 1: Partial reprogramming with TRE-OSK leads to increased lifespan and improved frailty scores in very old mice. (a) Schematic of the constructs, virus, and injection route used in the study. (b) Kaplan-Meier curves for 124-week WT mice injected with AAV9.TRE-OSK and AAV9.hEF1?-rtTA4 (both 1E12 vg/animal) via the retro-orbital route, and induced with one week on/off doxycycline paradigm (TRE-OSK) showed median lifespan extension of remaining life by 109% compared to either doxycycline treated control animals (Control-Dox) or to historical published Jax data for Bl6/J mice (Jax historical). Red arrow indicates AAV injections. Mantel Cox Log rank test, ✱✱ p < 0.05. (c) Graph shows remaining lifespan of individual mice (after injections at week 124) for data shown in b. Two-tailed unpaired t-test; ✱✱ p < 0.05. (d) Frailty index (FI), the compound score of 28 different health parameters (range 0–1 in 0.5 increments), showed statistically-significant reduction in FI for TRE-OSK mice at 142 weeks of age (18 weeks after injections) as compared to Control-Dox mice. Student’s unpaired t-test, ✱✱ p < 0.05.