Positive association between physical activity and PER3 expression in older adults

Shank3 Deficiency Results in a Reduction in GABAergic Postsynaptic Puncta in the Olfactory Brain Areas

Dysfunctional sensory systems, including altered olfactory function, have recently been reported in patients with autism spectrum disorder (ASD). Disturbances in olfactory processing can potentially result from gamma-aminobutyric acid (GABA)ergic synaptic abnormalities. The specific molecular mechanism by which GABAergic transmission affects the olfactory system in ASD remains unclear. Therefore, the present study aimed to evaluate selected components of the GABAergic system in olfactory brain regions and primary olfactory neurons isolated from Shank3-deficient (-/-) mice, which are known for their autism-like behavioral phenotype. Shank3 deficiency led to a significant reduction in GEPHYRIN/GABAAR colocalization in the piriform cortex and in primary neurons isolated from the olfactory bulb, while no change of cell morphology was observed. Gene expression analysis revealed a significant reduction in the mRNA levels of GABA transporter 1 in the olfactory bulb and Collybistin in the frontal cortex of the Shank3-/- mice compared to WT mice. A similar trend of reduction was observed in the expression of Somatostatin in the frontal cortex of Shank3-/- mice. The analysis of the expression of other GABAergic neurotransmission markers did not yield statistically significant results. Overall, it appears that Shank3 deficiency leads to changes in GABAergic synapses in the brain regions that are important for olfactory information processing, which may represent basis for understanding functional impairments in autism.

Chronotherapeutic Approaches

The chapter provides a comprehensive review of current approaches to personalized chronodiagnosis and chronotherapy. We discuss circadian clock drug targets that aim to affect cellular clock machinery, circadian mechanisms of pharmacokinetics/pharmacodynamics, and chronotherapeutic approaches aimed at increasing treatment efficacy and minimizing its side effects. We explore how chronotherapy can combat acquired and compensatory drug resistance. Non-pharmacological interventions for clock preservation and enhancement are also overviewed, including light treatment, melatonin, sleep scheduling, time-restricted feeding, physical activity, and exercise.

Association between circadian clock gene expressions and meal timing in young and older adults

Ageing is associated with a decline in circadian clock systems, which correlates with the development of ageing-associated diseases. Chrononutrition is a field of chronobiology that examines the relationship between the timing of meal/nutrition and circadian clock systems. Although there is growing evidence regarding the role of chrononutrition in the prevention of lifestyle and ageing-related diseases, the optimal timing of meal intake to regulate the circadian clock in humans remains unknown. In this study, we investigated the relationship between clock gene expression and meal timing in young and older adults. In this cross-sectional study, we enrolled 51 healthy young men and 35 healthy older men (age, mean±standard deviation: 24 ± 4 and 70 ± 4 y, respectively). Under daily living conditions, beard follicle cells were collected at 4-h intervals over a 24-h period to evaluate clock gene expression. Participants were asked to record the timing of habitual sleep and wake-up, breakfast, lunch, and dinner. From these data, we calculated "From bedtime to breakfast time," "From wake up to first meal time," and "From dinner to bed time." NR1D1 and PER3 expressions in older adults at 06:00 h were significantly higher than those in young adults (P = 0.001). There were significant differences in the peak time for NR1D2 (P = 0.003) and PER3 (P = 0.049) expression between young and older adults. "From bedtime to breakfast time" was significantly longer in older adults than in young adults. In contrast, "From dinner to bed time" was significantly shorter in older adults than in young adults. Moreover, higher rhythmicity of NR1D1 correlated with longer "From bedtime to breakfast time" (r =  -0.470, P = 0.002) and shorter "From wake up to first meal time" in young adults (r = 0.302, P = 0.032). Higher rhythmicity of PER3 correlated with longer "From bedtime to breakfast time" in older adults (r =  -0.342, P = 0.045). These results suggest that the peak time of clock gene expression in older adults may be phase-advanced compared to that in young adults. In addition, a longer fasting duration from bedtime to breakfast in both young and older adults and earlier intake of meals after waking up in young adults may correlate with robust clock gene expression rhythms.

Evaluation of a circadian rhythm gene (PER3) VNTR variant in Turkish athletes

OBJECTIVE

Circadian rhythmicity has been shown to contribute to the regulation of key physiological and cognitive processes related to performance. The period homolog 3 (PER3) is expressed in a circadian pattern in the suprachiasmatic nucleus. Therefore, in this study, we aimed to evaluate the role of the variable tandem repeat (VNTR) variant of the PER3 gene in athletic performance in the Turkish population.

METHODS

This study included 223 subjects, which consisted of 123 athletes and 100 sedentary controls. Blood samples were drawn from all subjects. DNA was extracted from whole-blood samples. The PER3 VNTR variant was genotyped using the polymerase chain reaction-restriction method (PCR). The results of the analyses were evaluated for statistical significance.

RESULTS

The mean ages of athletes and controls were 22 ± 2.814 and 23 ± 3.561, respectively. Endurance athletes in the group were 21.1%, and sprint athletes were 78.9%. There was no statistical significance in terms of PER3 VNTR genotype distribution or allele frequency. In the recessive model, a statistically significant association was observed when the athletes were compared with the controls according to 4/4 + 4/5 versus 5/5 genotype (p = 0.020).

CONCLUSION

In this case-control study, for the first time in our country, we obtained findings suggesting that the PER3 VNTR variant may affect sports performance in the Turkish population. Results need to be replicated in different ethnic and larger samples.

Hair Follicles as a Critical Model for Monitoring the Circadian Clock

Clock (circadian) genes are heterogeneously expressed in hair follicles (HFs). The genes can be modulated by both the central circadian system and some extrinsic factors, such as light and thyroid hormones. These circadian genes participate in the regulation of several physiological processes of HFs, including hair growth and pigmentation. On the other hand, because peripheral circadian genes are synchronized with the central clock, HFs could provide a noninvasive and practical method for monitoring and evaluating multiple circadian-rhythm-related conditions and disorders among humans, including day and night shifts, sleep-wake disorders, physical activities, energy metabolism, and aging. However, due to the complexity of circadian biology, understanding how intrinsic oscillation operates using peripheral tissues only may be insufficient. Combining HF sampling with multidimensional assays such as detection of body temperature, blood samples, or certain validated questionnaires may be helpful in improving HF applications. Thus, HFs can serve as a critical model for monitoring the circadian clock and can help provide an understanding of the potential mechanisms of circadian-rhythm-related conditions; furthermore, chronotherapy could support personalized treatment scheduling based on the gene expression profile expressed in HFs.

Identification of the potential biomarkers associated with circadian rhythms in heart failure

Background

Heart failure (HF) is a syndrome with multiple clinical symptoms resulting from damage to the heart's structure and/or function with various pathogenic factors, which has developed as one of the most severe threats to human health. Approximately 13% of genes and about 8% of proteins contained in the heart are rhythmic, which could lead to HF if disrupted. Herein, we aimed to identify the circadian rhythms-related hub genes as potential biomarkers contributing to the identification and treatment of HF.

Methods

Expression data of ischemic and dilated cardiomyopathy samples with or without HF were collected from the GEO database. First, genes with differential expression in HF and healthy samples were identified, named as differentially expressed genes (DEGs), which were then intersected with circadian rhythms-related genes to identify circadian rhythms-related DEGs. A protein-protein interaction (PPI) network was established to screen hub genes. The performance of the hub genes to identify HF among healthy controls was assessed by referring to the receiver operating characteristic (ROC) curve. Additionally, quantitative real-time polymerase chain reaction (RT-PCR) was run to further validate the hub genes depending on clinical human peripheral blood samples.

Results

A total of 10,163 DEGs were determined, composed of 4,615 up-regulated genes and 5,548 down-regulated genes in HF patients in comparison to healthy controls. By overlapping the circadian rhythms-related genes in the Circadian Gene DataBase (CGDB), 723 circadian rhythms-related DEGs were obtained, mainly enriched in regulating lipid metabolic process, circadian rhythm and AMPK signaling pathway. Eight hub genes were screened out through the PPI network. The ROC curve indicated the high accuracy of five hub genes with AUC > 0.7, which also showed high accuracy validated by the external validation dataset. Furthermore, according to the results of quantitative RT-PCR, the HF group showed significantly increased relative mRNA expression of CRY2 and BHLHE41 while the decreased ARNTL and NPAS2 in comparison to controls, indicating the four hub genes as potential biomarkers of HF.

Conclusion

Our study validated that ARNTL, CRY2, BHLHE41 and NPAS2 could serve as potential biomarkers of circadian rhythm in HF. These results may provide a reference for employing novel markers or targets for the diagnosis and treatment of HF.

Deciphering clock genes as emerging targets against aging

The old people often suffer from circadian rhythm disturbances, which in turn accelerate aging. Many aging-related degenerative diseases such as Alzheimer's disease, Parkinson's disease, and osteoarthritis have an inextricable connection with circadian rhythm. In light of the predominant effects of clock genes on regulating circadian rhythm, we systematically present the elaborate network of roles that clock genes play in aging in this review. First, we briefly introduce the basic background regarding clock genes. Second, we systemically summarize the roles of clock genes in aging and aging-related degenerative diseases. Third, we discuss the relationship between clock genes polymorphisms and aging. In summary, this review is intended to clarify the indispensable roles of clock genes in aging and sheds light on developing clock genes as anti-aging targets.

The Impact of Physical Activity on the Circadian System: Benefits for Health, Performance and Wellbeing

Circadian rhythms are an inherent property of all living systems and an essential part of the external and internal temporal order. They enable organisms to be synchronized with their periodic environment and guarantee the optimal functioning of organisms. Any disturbances, so-called circadian disruptions, may have adverse consequences for health, physical and mental performance, and wellbeing. The environmental light–dark cycle is the main zeitgeber for circadian rhythms. Moreover, regular physical activity is most useful. Not only does it have general favorable effects on the cardiovascular system, the energy metabolism and mental health, for example, but it may also stabilize the circadian system via feedback effects on the suprachiasmatic nuclei (SCN), the main circadian pacemaker. Regular physical activity helps to maintain high-amplitude circadian rhythms, particularly of clock gene expression in the SCN. It promotes their entrainment to external periodicities and improves the internal synchronization of various circadian rhythms. This in turn promotes health and wellbeing. In experiments on Djungarian hamsters, voluntary access to a running wheel not only stabilized the circadian activity rhythm, but intensive wheel running even reestablished the rhythm in arrhythmic individuals. Moreover, their cognitive abilities were restored. Djungarian hamsters of the arrhythmic phenotype in which the SCN do not generate a circadian signal not only have a diminished cognitive performance, but their social memory is also compromised. Voluntary wheel running restored these abilities simultaneously with the reestablishment of the circadian activity rhythm. Intensively exercising Syrian hamsters are less anxious, more resilient to social defeat, and show less defensive/submissive behaviors, i.e., voluntary exercise may promote self-confidence. Similar effects were described for humans. The aim of the present paper is to summarize the current knowledge concerning the effects of physical activity on the stability of the circadian system and the corresponding consequences for physical and mental performance.

Polyadenylation and degradation of structurally abnormal mitochondrial tRNAs in human cells

RNA 3' polyadenylation is known to serve diverse purposes in biology, in particular, regulating mRNA stability and translation. Here we determined that, upon exposure to high levels of the intercalating agent ethidium bromide (EtBr), greater than those required to suppress mitochondrial transcription, mitochondrial tRNAs in human cells became polyadenylated. Relaxation of the inducing stress led to rapid turnover of the polyadenylated tRNAs. The extent, kinetics and duration of tRNA polyadenylation were EtBr dose-dependent, with mitochondrial tRNAs differentially sensitive to the stress. RNA interference and inhibitor studies indicated that ongoing mitochondrial ATP synthesis, plus the mitochondrial poly(A) polymerase and SUV3 helicase were required for tRNA polyadenylation, while polynucleotide phosphorylase counteracted the process and was needed, along with SUV3, for degradation of the polyadenylated tRNAs. Doxycycline treatment inhibited both tRNA polyadenylation and turnover, suggesting a possible involvement of the mitoribosome, although other translational inhibitors had only minor effects. The dysfunctional tRNALeu(UUR) bearing the pathological A3243G mutation was constitutively polyadenylated at a low level, but this was markedly enhanced after doxycycline treatment. We propose that polyadenylation of structurally and functionally abnormal mitochondrial tRNAs entrains their PNPase/SUV3-mediated destruction, and that this pathway could play an important role in mitochondrial diseases associated with tRNA mutations.

The effect of night shift work on the expression of clock genes in beard hair follicle cells

OBJECTIVE

Shift work encompasses a broad range of work time arrangements. However, how shift work affects the circadian expression of clock genes remains to be explored. The objective of this study was to evaluate the pattern of clock gene expression in shift workers in the field.

METHODS

We examined clock gene expression in Japanese men who work: (1) one night shift followed by a day off (caregivers: nurses and doctors; the one-night group); (2) three or more consecutive night shifts (factory workers; the consecutive-night group); or (3) daytime only (the daytime group), using beard follicle samples. The expression of Period3, Nuclear Receptor Subfamily 1 Group D Member 1 (Nr1d1), and Nuclear Receptor Subfamily 1 Group D Member 2 (Nr1d2) was examined by real-time polymerase chain reaction.

RESULTS

Period3 expression in the daytime and one-night groups together with Nr1d2 expression in the one-night group fitted a 24-h-period cosine curve better than in the consecutive-night group (p = 0.004, 0.012, and 0.001, respectively). The level of overall Period3 gene expression, calibrated with that of 18S-rRNA, was decreased in the consecutive-night group compared with that in the daytime group (p = 0.006). The patterns of Period3 and Nr1d2 expression in the daytime and one-night groups were more coherent than those in the consecutive-night group.

CONCLUSIONS

These results suggest that night shift work affects the rhythms and levels of circadian Period3 and Nr1d2 expression dependent on the shift schedule or type of the shift; however, there is substantial variation between individuals.

Chronotype and social jetlag influence human circadian clock gene expression

We examined the relationships between chronotype or social jetlag and clock gene expression. Twenty-four young men [Chronotype: morningness, n = 8; intermediate, n = 8, eveningness, n = 8], aged 27 ± 2 years old (mean ± SE), completed two trials in a randomized order: (1) a Friday trial and (2) a Monday trial. In both trials, hair follicle cells were collected to evaluate the expression of clock genes over a 24-hour period at 4-hour intervals. There was a significant main effect of time on the expression of NR1D1, NR1D2, and PER3 (P < 0.001) in the morningness group, but not in the eveningness group. Changes in the peak time of expression of NR1D1 (r = 0.434, P = 0.034), NR1D2 (r = 0.481, P = 0.017), and PER3 (r = 0.457, P = 0.025) from the Friday to Monday trials were positively correlated with social jetlag (SJL) time. Our findings indicate that there was no change in the patterns of clock gene expression between workdays and the day after the holiday in the morningness group, and that SJL time influences the peak time of clock gene expression, moving it from the early to late workday, after a holiday.

Human hair follicle transcriptome profiling: a minimally invasive tool to assess molecular adaptations upon low-volume, high-intensity interval training

High‐intensity interval training (HIIT) has become a popular fitness training approach under both civilian and military settings. Consisting of brief and intense exercise intervals, HIIT requires less time commitment yet is able to produce the consistent targeted physical adaptations as conventional endurance training. To effectively characterize and monitor HIIT‐induced cellular and molecular responses, a highly accessible yet comprehensive biomarker discovery source is desirable. Both gene differential expression (DE) and gene set (GS) analyses were conducted using hair follicle transcriptome established from pre and postexercise subjects upon a 10‐day HIIT program by RNA‐Seq, Comparing between pre and posttraining groups, differentially expressed protein coding genes were identified. To interpret the functional significance of the DE results, a comprehensive GS analysis approach featuring multiple algorithms was used to enrich gene ontology (GO) terms and KEGG pathways. The GS analysis revealed enriched themes such as energy metabolism, cell proliferation/growth/survival, muscle adaptations, and cytokine–cytokine interaction, all of which have been previously proposed as HIIT responses. Moreover, related cell signaling pathways were also measured. Specifically, G‐protein‐mediated signal transduction, phosphatidylinositide 3‐kinases (PI3K) – protein kinase B (PKB) and Janus kinase (JAK) – Signal Transducer and Activator of Transcription (STAT) signaling cascades were over‐represented. Additionally, the RNA‐Seq analysis also identified several HIIT‐responsive microRNAs (miRNAs) that were involved in regulating hair follicle‐specific processes, such as miR‐99a. For the first time, this study demonstrated that both existing and new biomarkers like miRNA can be explored for HIIT using the transcriptomic responses exhibited by the hair follicle.