Genetic Variation in FOXO3 is Associated with Self-Rated Health in a Population-Based Sample of Older Individuals

Cross-sectional and longitudinal associations between late-life depressive symptoms and cognitive deficits: 20-year follow-up of the Kuakini Honolulu-Asia aging study

OBJECTIVE

To examine depressed affect, somatic complaints, and positive affect as longitudinal predictors of fluid, crystallized and global cognitive performance in the Kuakini Honolulu-Asia Aging Study (HAAS), a large prospective cohort study of Japanese-American men.

METHODS

We assessed 3,088 dementia-free Kuakini-HAAS participants aged 71-93 (77.1 ± 4.2) years at baseline (1991-1993). Depressive symptoms were evaluated by the Center for Epidemiologic Studies Depression (CES-D) Scale. Baseline CES-D depression subscales (depressed and positive affects; somatic complaints) were computed. The Cognitive Abilities Screening Instrument (CASI) measured cognitive performance on a 100-point scale; fluid and crystallized cognitive abilities were derived from CASI factor analysis. Cognition was also evaluated at 4 follow-up examinations over a 20-year period. Multiple regression assessed baseline CES-D subscales as predictors of cognitive change. The baseline covariates analyzed were CASI, age, education, prevalent stroke, APOE ε4 presence, and the longevity-associated FOXO3 genotype.

RESULTS

Cross-sectionally, baseline CES-D subscales were related to cognitive measures; e.g., higher depressed affect was associated with lower crystallized ability (β = -0.058, p ≤ 0.01), and somatic complaints were linked to poorer fluid ability (β = -0.045, p ≤ 0.05) and to worse global cognitive function as measured by total CASI score (β = -0.038, p ≤ 0.05). However, depression subscales did not significantly or consistently predict fluid ability, crystallized ability, or global cognitive performance over time.

CONCLUSION

Psychological and physical well-being were associated with contemporaneous but not subsequent cognitive functioning. Assessment of depressive symptoms may identify individuals who are likely to benefit from interventions to improve mood and somatic health and thereby maintain or enhance cognition.

FOXO3A-short is a novel regulator of non-oxidative glucose metabolism associated with human longevity

Intronic single-nucleotide polymorphisms (SNPs) in FOXO3A are associated with human longevity. Currently, it is unclear how these SNPs alter FOXO3A functionality and human physiology, thereby influencing lifespan. Here, we identify a primate-specific FOXO3A transcriptional isoform, FOXO3A-Short (FOXO3A-S), encoding a major longevity-associated SNP, rs9400239 (C or T), within its 5' untranslated region. The FOXO3A-S mRNA is highly expressed in the skeletal muscle and has very limited expression in other tissues. We find that the rs9400239 variant influences the stability and functionality of the primarily nuclear protein(s) encoded by the FOXO3A-S mRNA. Assessment of the relationship between the FOXO3A-S polymorphism and peripheral glucose clearance during insulin infusion (Rd clamp) in a cohort of Danish twins revealed that longevity T-allele carriers have markedly faster peripheral glucose clearance rates than normal lifespan C-allele carriers. In vitro experiments in human myotube cultures utilizing overexpression of each allele showed that the C-allele represses glycolysis independently of PI3K signaling, while overexpression of the T-allele represses glycolysis only in a PI3K-inactive background. Supporting this finding inducible knockdown of the FOXO3A-S C-allele in cultured myotubes increases the glycolytic rate. We conclude that the rs9400239 polymorphism acts as a molecular switch which changes the identity of the FOXO3A-S-derived protein(s), which in turn alters the relationship between FOXO3A-S and insulin/PI3K signaling and glycolytic flux in the skeletal muscle. This critical difference endows carriers of the FOXO3A-S T-allele with consistently higher insulin-stimulated peripheral glucose clearance rates, which may contribute to their longer and healthier lifespans.

Pharmaceutical and nutraceutical activation of FOXO3 for healthy longevity

Life expectancy has increased substantially over the last 150 years. Yet this means that now most people also spend a greater length of time suffering from various age-associated diseases. As such, delaying age-related functional decline and extending healthspan, the period of active older years free from disease and disability, is an overarching objective of current aging research. Geroprotectors, compounds that target pathways that causally influence aging, are increasingly recognized as a means to extend healthspan in the aging population. Meanwhile, FOXO3 has emerged as a geroprotective gene intricately involved in aging and healthspan. FOXO3 genetic variants are linked to human longevity, reduced disease risks, and even self-reported health. Therefore, identification of FOXO3-activating compounds represents one of the most direct candidate approaches to extending healthspan in aging humans. In this work, we review compounds that activate FOXO3, or influence healthspan or lifespan in a FOXO3-dependent manner. These compounds can be classified as pharmaceuticals, including PI3K/AKT inhibitors and AMPK activators, antidepressants and antipsychotics, muscle relaxants, and HDAC inhibitors, or as nutraceuticals, including primary metabolites involved in cell growth and sustenance, and secondary metabolites including extracts, polyphenols, terpenoids, and other purified natural compounds. The compounds documented here provide a basis and resource for further research and development, with the ultimate goal of promoting healthy longevity in humans.

The association between longevity associated FOXO3 allele and heart disease in Septuagenarians and Octogenarians: The SONIC study

The G allele of FOXO3 gene (single-nucleotide polymorphism; rs2802292) is strongly associated with human longevity. However, knowledge of the effect of FOXO3 in older populations, men or women, with heart disease is limited. This cross-sectional study in Japan included 1836 older adults in the 70- and 80-year-old groups. DNA samples isolated from buffy coat samples of peripheral blood were used to genotype FOXO3 (rs2802292). Self-reports were used to obtain heart disease data according to physician diagnosis. Multiple logistic regression was used to test the association by adjusting for the traditional risk factor of heart disease. The prevalence of heart disease in women FOXO3 G-allele carriers was higher than noncarriers (16.7% vs 11.6%, p = .022). The prevalence of coronary heart disease was lower for FOXO3 G carriers in the 70-year-old group for both sexes (men: 9.3% vs 4.3%, p = .042 and women: 10% vs 9%, p = .079, respectively). The G allele was negatively associated with heart disease after adjusting for diabetes, hypertension, dyslipidemia, and smoking in men (odds ratio [OR] = 0.70, 95% confidence intervals [CIs], 0.49–0.99, p = .046), although the association was weaker after full adjustment. In contrast, women carriers of the FOXO3 G allele showed a positive association with heart disease after total adjustment (OR = 1.49, 95% CI, 1.00–2.21, p = .049). In conclusion, the longevity-associated G allele of FOXO3 was observed to have contrasting associations with heart disease prevalence according to sex in older Japanese. To further confirm this association, a longitudinal study and a large sample size will be required.

FOXO3 longevity genotype mitigates the increased mortality risk in men with a cardiometabolic disease

FOXO3 is a prominent longevity gene. To date, no-one has examined whether longevity-associated FOXO3 genetic variants protect against mortality in all individuals, or only in those with aging-related diseases. We therefore tested longevity-associated FOXO3 single nucleotide polymorphisms in a haplotype block for association with mortality in 3,584 elderly American men of Japanese ancestry, 2,512 with and 1,072 without a cardiometabolic disease (CMD). At baseline (1991–1993), 1,010 CMD subjects had diabetes, 1,919 had hypertension, and 738 had coronary heart disease (CHD). Follow-up until Dec 31, 2019 found that in CMD-affected individuals, longevity-associated alleles of FOXO3 were associated with significantly longer lifespan: haplotype hazard ratio 0.81 (95% CI 0.72-0.91; diabetes 0.77, hypertension 0.82, CHD 0.83). Overall, men with a CMD had higher mortality than men without a CMD (P=6x10^-7). However, those men with a CMD who had the FOXO3 longevity genotype had similar survival as men without a CMD. In men without a CMD there was no association of longevity-associated alleles of FOXO3 with lifespan. Our study provides novel insights into the basis for the long-established role of FOXO3 as a longevity gene. We suggest that the FOXO3 longevity genotype increases lifespan only in at-risk individuals by protection against cardiometabolic stress.

Predicting Health-Related Quality of Life in Trauma-Exposed Male Veterans in Late Midlife: A 20 Year Longitudinal Study

Trauma-exposed adults with high levels of posttraumatic stress symptoms (PTSS) report poorer health-related quality of life (HRQOL), but less is known about the persistence of this relationship over time. Participants from the Vietnam Era Twin Study of Aging reported on PTSS, health, and sociodemographic characteristics at average age 38; 775 participants reported having been exposed to trauma. Later, at average ages 56 and 62, mental and physical HRQOL were assessed with the Short-Form 36. Premorbid risk for anxiety/neuroticism was evaluated with a polygenic risk score derived from a large genome-wide association study meta-analysis. In multivariate mixed models, having higher levels of PTSS, poorer self-rated health, lower income, and less education at age 38 were associated with worse physical and mental HRQOL two decades later. Chronic health problems at age 38 predicted midlife physical but not mental HRQOL. Although genetic risk for neuroticism was correlated with HRQOL and PTSS, it was no longer significant in multivariate models. Health-related quality of life (HRQOL) predicts morbidity and mortality independently of objective health measures; early interventions may help to mitigate the ongoing impact of trauma on quality of life.

Genetic and epigenetic regulation of human aging and longevity

Here we summarize the latest data on genetic and epigenetic contributions to human aging and longevity. Whereas environmental and lifestyle factors are important at younger ages, the contribution of genetics appears more important in reaching extreme old age. Genome-wide studies have implicated ~57 gene loci in lifespan. Epigenomic changes during aging profoundly affect cellular function and stress resistance. Dysregulation of transcriptional and chromatin networks is likely a crucial component of aging. Large-scale bioinformatic analyses have revealed involvement of numerous interaction networks. As the young well-differentiated cell replicates into eventual senescence there is drift in the highly regulated chromatin marks towards an entropic middle-ground between repressed and active, such that genes that were previously inactive "leak". There is a breakdown in chromatin connectivity such that topologically associated domains and their insulators weaken, and well-defined blocks of constitutive heterochromatin give way to generalized, senescence-associated heterochromatin, foci. Together, these phenomena contribute to aging.

FOXO3 on the Road to Longevity: Lessons From SNPs and Chromatin Hubs

Health span is driven by a precise interplay between genes and the environment. Cell response to environmental cues is mediated by signaling cascades and genetic variants that affect gene expression by regulating chromatin plasticity. Indeed, they can promote the interaction of promoters with regulatory elements by forming active chromatin hubs.

FOXO3 encodes a transcription factor with a strong impact on aging and age-related phenotypes, as it regulates stress response, therefore affecting lifespan. A significant association has been shown between human longevity and several FOXO3 variants located in intron 2. This haplotype block forms a putative aging chromatin hub in which FOXO3 has a central role, as it modulates the physical connection and activity of neighboring genes involved in age-related processes.

Here we describe the role of FOXO3 and its single-nucleotide polymorphisms (SNPs) in healthy aging, with a focus on the enhancer region encompassing the SNP rs2802292, which upregulates FOXO3 expression and can promote the activity of the aging hub in response to different stress stimuli. FOXO3 protective effect on lifespan may be due to the accessibility of this region to transcription factors promoting its expression. This could in part explain the differences in FOXO3 association with longevity between genders, as its activity in females may be modulated by estrogens through estrogen receptor response elements located in the rs2802292-encompassing region. Altogether, the molecular mechanisms described here may help establish whether the rs2802292 SNP can be taken advantage of in predictive medicine and define the potential of targeting FOXO3 for age-related diseases.

Recent advances in understanding the role of FOXO3

The forkhead box O3 (FOXO3, or FKHRL1) protein is a member of the FOXO subclass of transcription factors. FOXO proteins were originally identified as regulators of insulin-related genes; however, they are now established regulators of genes involved in vital biological processes, including substrate metabolism, protein turnover, cell survival, and cell death. FOXO3 is one of the rare genes that have been consistently linked to longevity in in vivo models. This review provides an update of the most recent research pertaining to the role of FOXO3 in (i) the regulation of protein turnover in skeletal muscle, the largest protein pool of the body, and (ii) the genetic basis of longevity. Finally, it examines (iii) the role of microRNAs in the regulation of FOXO3 and its impact on the regulation of the cell cycle.