Machine learning and expression analyses reveal circadian clock features predictive of anxiety

Abstract

Mood disorders, including generalized anxiety disorder, are associated with disruptions in circadian rhythms and are linked to polymorphisms in circadian clock genes. Molecular mechanisms underlying these connections may be direct—via transcriptional activity of clock genes on downstream mood pathways in the brain, or indirect—via clock gene influences on the phase and amplitude of circadian rhythms which, in turn, modulate physiological processes influencing mood. Employing machine learning combined with statistical approaches, we explored clock genotype combinations that predict risk for anxiety symptoms in a deeply phenotyped population. We identified multiple novel circadian genotypes predictive of anxiety, with the PER3(rs17031614)-AG/CRY1(rs2287161)-CG genotype being the strongest predictor of anxiety risk, particularly in males. Molecular chronotyping, using clock gene expression oscillations, revealed that advanced circadian phase and robust circadian amplitudes are associated with high levels of anxiety symptoms. Further analyses revealed that individuals with advanced phases and pronounced circadian misalignment were at higher risk for severe anxiety symptoms. Our results support both direct and indirect influences of clock gene variants on mood: while sex-specific clock genotype combinations predictive of anxiety symptoms suggest direct effects on mood pathways, the mediation of PER3 effects on anxiety via diurnal preference measures and the association of circadian phase with anxiety symptoms provide evidence for indirect effects of the molecular clockwork on mood. Unraveling the complex molecular mechanisms underlying the links between circadian physiology and mood is essential to identifying the core clock genes to target in future functional studies, thereby advancing the development of non-invasive treatments for anxiety-related disorders.

Diurnal circadian clock gene expression is altered in models of genetic and acquired epilepsy

“…KASE (n = 8) and shams (n = 8) per CT. disorders. 34,35 Similarly, altered hypothalamic and hippocampal Per1 and Bmal1 expression patterns have been described in a murine model of depressive-like behavior. 36,37 Currently, it is unclear the involvement of clock genes in the formation of memory; however, reduction in hippocampal Per1 using short interfering RNA, impairs learning and Per1 knockouts show perturbed hippocampal learning-dependent histone modifications.…”

“…Altered clock gene expression has not been studied in epilepsy comorbidities. However, per gene polymorphisms correlate with increased depression risk and anxiety disorders 34,35 . Similarly, altered hypothalamic and hippocampal Per1 and Bmal1 expression patterns have been described in a murine model of depressive‐like behavior 36,37 .…”

Machine Learning Analyses Reveal Circadian Clock Features Predictive of Anxiety Among UK Biobank Participants

“…However, many of these studies have utilized GWAS and PheWAS approaches making it di cult to detect synergistic effects between genotypes or to explore whether signi cant genotypes are directly or indirectly associated with anxiety. Novel machine learning approaches have shown promise in illuminating these synergistic effects and proposing potential mechanisms of clock pathways that may in uence anxiety (Zafar et al, 2022) and sleep disturbance (Overton et al, 2022). Utilizing similar machine learning approaches to analyze clock gene associations with anxiety in a large UK Biobank dataset, we report three main ndings: (1) Clock genotype combinations including ZBTB20 variants exhibit combination-speci c effects on anxiety, (2) Clock variant combinations associated with anxiety tend to display sex-speci c effects, and (3) Circadian-related variants linked to anxiety risk have both direct (chronotype-independent) in uences and indirect (chronotype-mediated) in uences on anxiety symptoms.…”

“…In males, CRY1_CC/PER3A_GG was a risk factor for severe anxiety and PER3B_GG/ZBTB20_TT was a risk factor for mild anxiety. Sex-speci c associations with circadian genes have previously been observed for anxiety (Zafar et al, 2022) and major depressive disorder (MDD) (Shi et al, 2016).…”

“…GAD-7 scores have been broken into thresholds where scores ≤ 4 indicate minimal anxiety, 5-9 suggest mild anxiety, 10-14 suggest moderate anxiety, and ≥ 15 indicate severe anxiety. Since a score of 8 is a commonly held cutoff for a more in-depth examination (Johnson et al, 2019;Plummer et al, 2016), we used the following thresholds: mild anxiety (8-11), moderate anxiety (12)(13)(14)(15), and severe anxiety (≥ 16). We split these categories into three different binary outcomes for multiple multivariate logistic regression analyses.…”