Biology subjects

Cho, H. R.

Publications and source records attributed to Cho, H. R..

4 recordsLinked to original sources

bioRxiv2022

Metformin use history and genome-wide DNA methylation profile: potential molecular mechanism for aging and longevity

BackgroundWhile there are medications that treat and manage age-related diseases, a compound that prolongs lifespan is yet to be discovered. Nonetheless, metformin, a commonly prescribed anti-diabetic medication, has repeatedly been shown to hinder aging in pre-clinical models and to be associated with lower mortality for humans, even among cancer patients. It is, however, not well understood how metformin can potentially prolong lifespan from a biological standpoint. We hypothesized that metformins potential mechanism of action for longevity is through its epigenetic modifications. MethodsTo test our hypothesis, we conducted a post-hoc analysis of available genome-wide DNA methylation (DNAm) data obtained from whole blood collected from inpatients with and without a history of metformin use. We assessed the methylation profile of 171 patients (first run) and only among 63 diabetic patients (second run) and compared the DNAm rates between metformin users and nonusers. ResultsEnrichment analysis from the Kyoto Encyclopedia of Genes and Genome (KEGG) showed pathways relevant to metformins mechanism of action, such as longevity, AMPK, and inflammatory pathways. We also identified several pathways related to delirium whose risk factor is aging. Moreover, top hits from the Gene Ontology (GO) included HIF-1 pathways. However, no individual CpG site showed genome-wide statistical significance (p<5E-08). ConclusionThis study may elucidate metformins potential role in longevity through epigenetic modifications and other possible mechanisms of action.

genetics↗

bioRxiv2022

Epigenetics of post-operative delirium: A genome-wide DNA methylation study of neurosurgery patients

AimsThere is no previous study demonstrating the differences of genome-wide DNA methylation (DNAm) profiles between patients with and without postoperative delirium (POD). We aimed to discover epigenetic (DNAm) markers that are associated with POD in blood obtained from patients before and after neurosurgery. MethodsPre- and post-surgical blood DNA samples from 37 patients, including 10 POD cases, were analyzed using the Illumina EPIC array genome-wide platform. We examined DNAm differences in blood from patients with and without POD. Enrichment analysis with Gene Ontology and Kyoto Encyclopedia of Genes and Genomes terms were also conducted. ResultsWhen POD cases were tested for DNAm change before and after surgery, enrichment analyses showed many relevant signals with statistical significance in immune response related-pathways and inflammatory cytokine related-pathways such as "cellular response to cytokine stimulus", "regulation of immune system process", "regulation of cell activation", and "regulation of cytokine production". Furthermore, after excluding the potential effect of common factors related to surgery and anesthesia between POD cases and non-POD controls, the enrichment analyses showed significant signals such as "immune response" and "T cell activation", which are same pathways previously identified from an independent non-surgical inpatient cohort. Conclusions: Our first genome-wide DNAm investigation of POD showed promising signals related to immune response, inflammatory response and other relevant signals considered to be associated with delirium pathophysiology. Our data supports the hypothesis that epigenetics are playing an important role in pathophysiological mechanism of delirium and suggest the potential usefulness of epigenetics based biomarker of POD.

neuroscience↗

bioRxiv2019

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

BackgroundThe 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.\n\nMethodsA 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.\n\nResultsOnly 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.\n\nConclusionsDNAm 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.

neuroscience↗

bioRxiv2019

DNA methylation change in neurotrophic genes with aging and delirium evidenced from three independent cohorts

INTRODUCTIONWe previously reported the association between DNA methylation (DNAm) of pro-inflammatory cytokine genes and aging. Neurotrophic factors are also known to be associated with aging and neurocognitive disorders. Thus, we hypothesized that DNAm of neurotrophic genes change with aging, especially in delirium patients.\n\nMETHODSDNAm were analyzed using HumanMethylationEPIC BeadChip Kit in 3 independent cohorts; blood from 383 Grady Trauma Project subjects, brain from 21 neurosurgery patients, and blood from 87 inpatients with and without delirium.\n\nRESULTSBoth blood and brain samples showed that most of the DNAm of neurotrophic genes were positively correlated with aging. Furthermore, DNAm of neurotrophic genes were positively correlated with aging in delirium cases than in non-delirium controls.\n\nDISCUSSIONThese findings support our hypothesis that the neurotrophic genes may be epigenetically modulated with aging, and this process may be contributing to the pathophysiology of delirium.

neuroscience↗