Biology subjects

Quach, A.

Publications and source records attributed to Quach, A..

3 recordsLinked to original sources

bioRxiv2018

An epigenetic biomarker of aging for lifespan and healthspan

Identifying reliable biomarkers of aging is a major goal in geroscience. While the first generation of epigenetic biomarkers of aging were developed using chronological age as a surrogate for biological age, we hypothesized that incorporation of composite clinical measures of phenotypic age that capture differences in lifespan and healthspan may identify novel CpGs and facilitate the development of a more powerful epigenetic biomarker of aging. Using a innovative two-step process, we develop a new epigenetic biomarker of aging, DNAm PhenoAge, that strongly outperforms previous measures in regards to predictions for a variety of aging outcomes, including all-cause mortality, cancers, healthspan, physical functioning, and Alzheimers disease. While this biomarker was developed using data from whole blood, it correlates strongly with age in every tissue and cell tested. Based on an in-depth transcriptional analysis in sorted cells, we find that increased epigenetic, relative to chronological age, is associated increased activation of pro-inflammatory and interferon pathways, and decreased activation of transcriptional/translational machinery, DNA damage response, and mitochondrial signatures. Overall, this single epigenetic biomarker of aging is able to capture risks for an array of diverse outcomes across multiple tissues and cells, and provide insight into important pathways in aging.

epidemiology↗

bioRxiv2017

Striatal cholinergic receptor activation causes a rapid, selective, & state-dependent rise in corticostriatal β activity.

Cortico-basal ganglia-thalamic (CBT) {beta} oscillations (15-30 Hz) are elevated in Parkinsons disease and correlated with movement disability. To date, no experimental paradigm outside of loss of dopamine has been able to specifically elevate {beta} oscillations in the CBT loop. Here, we show that activation of striatal cholinergic receptors selectively increased {beta} oscillations in mouse striatum and motor cortex. In individuals showing simultaneous {beta} increases in both striatum and M1, {beta} partial directed coherence (PDC) increased from striatum to M1 (but not in the reverse direction). In individuals that did not show simultaneous {beta} increases, {beta} PDC increased from M1 to striatum (but not in the reverse direction), and M1 was characterized by persistent {beta}-HFO phase-amplitude coupling. Finally, the direction of {beta} PDC distinguished between {beta} subbands. This suggests: (1) striatal cholinergic tone exerts state-dependent and frequency-selective control over CBT {beta} power and coordination; (2) ongoing rhythmic dynamics can determine whether elevated {beta} oscillations are expressed in striatum and M1; (3) altered striatal cholinergic tone differentially modulates distinct {beta} subbands.

neuroscience↗

bioRxiv2017

GWAS of epigenetic ageing rates in blood reveals a critical role for TERT

DNA methylation age is an accurate biomarker of chronological age and predicts lifespan, but its underlying molecular mechanisms are unknown. In this genome-wide association study of 9,907 individuals, we found gene variants mapping to five loci associated with intrinsic epigenetic age acceleration (IEAA) and gene variants in 3 loci associated extrinsic epigenetic age acceleration (EEAA). Mendelian randomization analysis suggested causal influences of menarche and menopause on IEAA and lipid levels on IEAA and EEAA. Variants associated with longer leukocyte telomere length (LTL) in the telomerase reverse transcriptase gene (TERT) locus at 5p15.33 confer higher IEAA (P<2.7x10-11). Causal modelling indicates TERT-specific and independent effects on LTL and IEAA. Experimental hTERT expression in primary human fibroblasts engenders a linear increase in DNA methylation age with cell population doubling number. Together, these findings indicate a critical role for hTERT in regulating the DNA methylation clock, in addition to its established role of compensating for cell replication-dependent telomere shortening.

genetics↗