Roles of physical exercise in neurodegeneration: reversal of epigenetic clock

The epigenetic clock is defined by the DNA methylation (DNAm) level and has been extensively applied to distinguish biological age from chronological age. Aging-related neurodegeneration is associated with epigenetic alteration, which determines the status of diseases. In recent years, extensive research has shown that physical exercise (PE) can affect the DNAm level, implying a reversal of the epigenetic clock in neurodegeneration. PE also regulates brain plasticity, neuroinflammation, and molecular signaling cascades associated with epigenetics. This review summarizes the effects of PE on neurodegenerative diseases via both general and disease-specific DNAm mechanisms, and discusses epigenetic modifications that alleviate the pathological symptoms of these diseases. This may lead to probing of the underpinnings of neurodegenerative disorders and provide valuable therapeutic references for cognitive and motor dysfunction.

Variable expressed methylation sites of aging-related genes in asthma

Background: Asthma is a complex pulmonary inflammatory disease which is common in the elderly. Aging-related alterations have also been found in the structural cells and immune cells of asthma patients although the pathological mechanism of the differential aging-related gene in the development of asthma is still obscure. Of note, DNA methylation (DNAm) have been proven to play an important role in the regulation of aging-related genes. However, the methylation levels of aging-related genes in asthma patients are largely unclear.Methods: First, the mRNA levels and DNAm level of the previous screened 9 aging-related genes in peripheral blood of 51 healthy controls (HCs) and 55 asthmatic patients were detected by multiple targeted bisulfite enrichment sequencing (MethTarget) and qPCR. Secondly, the correlation between the DNAm level of specific altered CpG sites and the pulmonary function indicators of asthma patients was evaluated. Lastly, the Receiver Operator Characteristic (ROC) curve and Principal Component Analysis (PCA) were used to identify the feasibility of the candidate CpG sites as asthma markers.Results: The mRNA expression of the 9 aging-related gene in peripheral blood of asthma patients was significantly different from those of HCs. Besides, the methylation level of the 9 aging-related genes also altered in asthma patients, and a total of 68 CpG sites were related to the severity of asthma. Notably, 10 of the 68 CpG sites had a significant relationship with pulmonary function parameters. Moreover, ROC curve and PCA analysis showed that the candidate differential methylation sites (DMSs) can be used as potential biomarkers for asthma.Conclusions: In summary, this study confirmed the changes in the mRNA expression and DNAm level of aging-related genes in asthma patients. The differential DMSs are associated with the clinical evaluation indicators of asthma, which may indicate the involvement of aging-related genes in the pathogenesis of asthma and provide some new possible biomarker of asthma.

Variable Expressed Methylation Sites of Aging-related Genes in Asthma

Background: Asthma is a complex pulmonary inflammatory disease which is common in the elderly. Aging-related alterations have also been found in the structural cells and immune cells of asthma patients although the pathological mechanism of the differential aging-related gene in the development of asthma is still obscure. Of note, DNA methylation (DNAm) have been proven to play an important role in the regulation of aging-related genes. However, the methylation levels of aging-related genes in asthma patients are largely unclear.Methods: First, the mRNA levels and DNAm level of the previous screened 9 aging-related genes in peripheral blood of 51 healthy controls (HCs) and 55 asthmatic patients were detected by multiple targeted bisulfite enrichment sequencing (MethTarget) and qPCR. Secondly, the correlation between the DNAm level of specific altered CpG sites and the pulmonary function indicators of asthma patients was evaluated. Lastly, the Receiver Operator Characteristic (ROC) curve and Principal Component Analysis (PCA) were used to identify the feasibility of the candidate CpG sites as asthma markers.Results: The mRNA expression of the 9 aging-related gene in peripheral blood of asthma patients was significantly different from those of HCs. Besides, the methylation level of the 9 aging-related genes also altered in asthma patients, and a total of 68 CpG sites were related to the severity of asthma. Notably, 10 of the 68 CpG sites had a significant relationship with pulmonary function parameters. Moreover, ROC curve and PCA analysis showed that the candidate differential methylation sites (DMSs) can be used as potential biomarkers for asthma.Conclusions:In summary, this study confirmed the changes in the mRNA expression and DNAm level of aging-related genes in asthma patients. The differential DMSs are associated with the clinical evaluation indicators of asthma, which may indicate the involvement of aging-related genes in the pathogenesis of asthma and provide some new possible biomarker of asthma.

Epigenetics biomarkers of delirium: immune response, inflammatory response and cholinergic synaptic involvement evidenced by genome-wide DNA methylation analysis of delirious inpatients

ABSTRACTBackgroundThe authors previously hypothesized the role of epigenetics in pathophysiology of delirium, and tested DNA methylation (DNAm) change among pro-inflammatory cytokines along with aging in blood, glia and neuron. The authors reported that DNAm level of the TNF-alpha decreases along with aging in blood and glia, but not in neuron; however, DNAm differences between delirium cases and non-delirium controls have not been investigated directly. Therefore, in the present study, DNAm differences in blood between delirium patients and controls without delirium were examined.MethodsA case-control study with 92 subjects was conducted. Whole blood samples were collected and genome-wide DNAm was measured by the Infinium HumanMethylationEPIC BeadChip arrays. The correlation between DNAm levels in the TNF-alpha and age, network analysis, and the correlation between age and DNAm age were tested.ResultsOnly delirium cases showed 3 CpGs sites in the TNF-alpha significantly correlated to age after multiple corrections. A genome-wide significant CpG site near the gene of LDLRAD4 was identified. In addition, network analysis showed several significant pathways with false discovery rate adjusted p-value < 0.05. The top pathway with GO was immune response, and the second top pathway with KEGG was cholinergic synapse. Although there was no statistically significant difference, DNAm age among non-delirium controls showed “slower aging” compared to delirium cases.ConclusionsDNAm differences were shown both at gene and network levels between delirium cases and non-delirium controls. This finding indicates that DNAm status in blood has a potential to be used as epigenetic biomarkers for delirium.

Epigenetic Biomarkers Are Applicable for Risk Stratification in Myelodysplastic Syndromes

Introduction: Myelodysplastic syndromes (MDS) are frequently associated with somatic mutations in epigenetic modifiers such as de novo methyltransferase 3A (DNMT3A). However, so far the significance of specific epigenetic modifications for disease stratification remains largely unknown. In this study, we investigated if epigenetic biomarkers, which were previously described to be relevant in acute myeloid leukemia (AML), are also of prognostic impact in MDS. Methods: Peripheral blood samples of MDS patients (n=126; f/m=59/67; median age 66; range 26-93) equally distributed across all risk groups based on the revised International Prognostic Scoring System (IPSS-R; very low/low=43; int=37; high/very high=43; n.a.=3) were analyzed at initial diagnosis. Genomic DNA was isolated, bisulfite converted, and DNA methylation (DNAm) level at selected genomic regions were determined by pyrosequencing as described before: (1) hypermethylation at a CpG site in complement component 1 subcomponent R (C1R), (2) an epigenetic age prediction with an Epigenetic-Aging-Signature based on three CpG sites located in the genes ITGA2B, ASPA and PDE4C, and (3) an epimutation in the DNMT3A locus, mimicking somatic mutations of this gene, were all reported to correlate with overall survival (OS) in AML patients. Results were subsequently compared to clinical parameters such as IPSS-R, leukemic progression, and OS. Results: A clear tendency for longer OS of MDS patients was observed if DNAm level at C1R was above median (22%; two-year survival 67% [95% CI 53-84%] in hypo- vs. 84% [95% CI 74-95%] in hypermethylated samples; P=0.071), which is in line with previous findings in AML samples. The predicted epigenetic age determined by the Epigenetic-Aging-Signature correlated moderately with the chronological age of the investigated MDS patients (R=0.42) and their OS (P=0.029). This effect was also seen in a multivariable analysis of this cohort including predicted and chronological age (P=0.040). Finally, we stratified MDS patients by the DNAm level of 10% in DNMT3A. Similar to AML, also MDS patients with higher methylation at the CpG site represented on a microarray (cg23009818) showed in tendency shorter OS (two-year survival 79% [95% CI 69-89%] in hypo- vs. 65% [95% CI 45-93%] in hypermethylated samples; P=0.110). In fact, this association was even more pronounced at a neighboring CpG site (two-year survival 83% [95% CI 74-92%] in hypo- vs. 49% [95% CI 29-84%] in hypermethylated samples; P=0.009; Figure A). Moreover, increased DNAm level at this neighboring CpG site in DNMT3A was indicative for progression into AML (after two years: 15% [95% CI 6-24%] in hypo- vs. 44% [95% CI 12-76%] in hypermethylated samples; P=0.011; Figure B). Of note, none of these markers correlated with IPSS-R categories indicating that they might provide independent prognostic parameters. Conclusion: The analyzed epigenetic biomarkers revealed prognostic relevance in MDS patients and we suggest considering them in future risk stratification models. Particularly the aberrant hypermethylation of DNMT3A, which may also result in alternative splicing of DNMT3A transcripts, was associated with accelerated leukemic progression and shorter OS. Figure Figure. Disclosures Božić: Cygenia GmbH: Consultancy. Wagner:Cygenia GmbH: Equity Ownership.

The epigenetic tracks of aging

Aging is associated with the deterioration of biological functions, which is either caused by accumulation of random defects or mediated by a controlled process. This article provides an overview of age-associated epigenetic alterations in the histone code, DNA-methylation (DNAm) pattern, and chromatin structure. In particular, age-related DNAm changes are highly reproducible at specific sites in the genome. The DNAm level at few CpGs facilitates estimation of chronological age and there is evidence that such predictions are indicative for biological age. Overall, aging appears to be associated with a tightly regulated epigenetic process, but the underlying mechanism remains to be elucidated.