DNA damage is presumed to be one type of stochastic macromolecular damage that contributes to aging, yet little is known about the precise mechanism by which DNA damage drives aging. Here, we attempt to address this gap in knowledge using DNA repair-deficient C. elegans and mice. ERCC1-XPF is a nuclear endonuclease required for genomic stability and loss of ERCC1 in humans and mice accelerates the incidence of age-related pathologies. Like mice, ercc-1 worms are UV sensitive, shorter lived, display premature functional decline and they accumulate spontaneous oxidative DNA lesions (cyclopurines) more rapidly than wild-type worms. We found that ercc-1 worms displayed early activation of DAF-16 relative to wild-type worms, which conferred resistance to multiple stressors and was important for maximal longevity of the mutant worms. However, DAF-16 activity was not maintained over the lifespan of ercc-1 animals and this decline in DAF-16 activation corresponded with a loss of stress resistance, a rise in oxidant levels and increased morbidity, all of which were cep-1/ p53 dependent. A similar early activation of FOXO3A (the mammalian homolog of DAF-16), with increased resistance to oxidative stress, followed by a decline in FOXO3A activity and an increase in oxidant abundance was observed in Ercc1-/- primary mouse embryonic fibroblasts. Likewise, in vivo, ERCC1-deficient mice had transient activation of FOXO3A in early adulthood as did middle-aged wild-type mice, followed by a late life decline. The healthspan and mean lifespan of ERCC1 deficient mice was rescued by inactivation of p53. These data indicate that activation of DAF-16/FOXO3A is a highly conserved response to genotoxic stress that is important for suppressing consequent oxidative stress. Correspondingly, dysregulation of DAF-16/FOXO3A appears to underpin shortened healthspan and lifespan, rather than the increased DNA damage burden itself.

Mice bred in 2017 and entered into the C2017 cohort were tested for possible lifespan benefits of (R/S)‐1,3‐butanediol (BD), captopril (Capt), leucine (Leu), the Nrf2‐activating botanical mixture PB125, sulindac, syringaresinol, or the combination of rapamycin and acarbose started at 9 or 16 months of age (RaAc9, RaAc16). In male mice, the combination of Rapa and Aca started at 9 months and led to a longer lifespan than in either of the two prior cohorts of mice treated with Rapa only, suggesting that this drug combination was more potent than either of its components used alone. In females, lifespan in mice receiving both drugs was neither higher nor lower than that seen previously in Rapa only, perhaps reflecting the limited survival benefits seen in prior cohorts of females receiving Aca alone. Capt led to a significant, though small (4% or 5%), increase in female lifespan. Capt also showed some possible benefits in male mice, but the interpretation was complicated by the unusually low survival of controls at one of the three test sites. BD seemed to produce a small (2%) increase in females, but only if the analysis included data from the site with unusually short‐lived controls. None of the other 4 tested agents led to any lifespan benefit. The C2017 ITP dataset shows that combinations of anti‐aging drugs may have effects that surpass the benefits produced by either drug used alone, and that additional studies of captopril, over a wider range of doses, are likely to be rewarding.

Glioblastoma tumors (GBM) are very heterogeneous, being comprised of several cell subtypes, including glioblastoma stem cells (GSC). These tumors have a high rate of recurrence after initial treatment and one of the most prevalent theories to explain this is the cancer stem cell theory, which proposes that glioblastomas arise from mutations that transform normal neural stem cells (NSC) into GSC, which are highly resistant to oxidative stress and anti-cancer therapies. Sulindac is a non-steroidal anti-inflammatory drug (NSAID) that has been shown to protect the normal cells against oxidative damage by initiating a preconditioning response, but selectively sensitizes several cancer cell lines to agents that affect mitochondrial respiration, resulting in enhanced killing of the cancer cells. These effects of sulindac are independent of its NSAID activity. There is little information on the effect of sulindac on normal and cancer stem cells. To study the effect of sulindac on both normal and cancer stem cells, we have isolated normal neural stem cells (NSC), from mice hippocampi and glioblastoma stem cells (GSC) from a glioma cell line, U87. As expected from previous studies sulindac can protect normal astrocytes against oxidative stress. Sulindac induces differentiation of both NSC and GSC cells and sulindac upregulates neurogenesis in NSC. The differentiated NSC are also protected from oxidative stress damage, whereas the differentiation of GSC by sulindac increases the sensitivity of these cells to agents that cause oxidative stress. The S epimer of sulindac is more effective than the R epimer in inducing neuronal differentiation in both NSC and GSC. These results indicate that the ability of sulindac to induce GSC differentiation may have therapeutic value in preventing tumour recurrence.

Alzheimer's disease (AD) is the leading cause of mortality, disability, and long‐term care burden in the United States, with women comprising the majority of AD diagnoses. While AD‐related dementia is associated with tau and amyloid beta accumulation, concurrent derangements in cerebral blood flow have been observed alongside these proteinopathies in humans and rodent models. The homeostatic production of nitric oxide synthases (NOS) becomes uncoupled in AD which leads to decreased NO‐mediated vasodilation and oxidative stress via the production of peroxynitrite (ONOO−∙) superoxide species. Here, we investigate the role of the novel protein arginine methyltransferase 4 (PRMT4) enzyme function and its downstream product asymmetric dimethyl arginine (ADMA) as it relates to NOS dysregulation and cerebral blood flow in AD. ADMA (type‐1 PRMT product) has been shown to bind NOS as a noncanonic ligand causing enzymatic dysfunction. Our results from RT‐qPCR and protein analyses suggest that aged (9−12 months) female mice bearing tau‐ and amyloid beta‐producing transgenic mutations (3xTg‐AD) express higher levels of PRMT4 in the hippocampus when compared to age‐ and sex‐matched C57BL6/J mice. In addition, we performed studies to quantify the expression and activity of different NOS isoforms. Furthermore, laser speckle contrast imaging analysis was indicative that 3xTg‐AD mice have dysfunctional NOS activity, resulting in reduced production of NO metabolites, enhanced production of free‐radical ONOO−, and decreased cerebral blood flow. Notably, the aforementioned phenomena can be reversed via pharmacologic PRMT4 inhibition. Together, these findings implicate the potential importance of PRMT4 signaling in the pathogenesis of Alzheimer's‐related cerebrovascular derangement.

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