Browsing by Author "Sarachana T."

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    Epigenetic Gene-Regulatory Loci in Alu Elements Associated with Autism Susceptibility in the Prefrontal Cortex of ASD
    (2023-04-01) Saeliw T.; Kanlayaprasit S.; Thongkorn S.; Songsritaya K.; Sanannam B.; Sae-Lee C.; Jindatip D.; Hu V.W.; Sarachana T.; Mahidol University
    Alu elements are transposable elements that can influence gene regulation through several mechanisms; nevertheless, it remains unclear whether dysregulation of Alu elements contributes to the neuropathology of autism spectrum disorder (ASD). In this study, we characterized transposable element expression profiles and their sequence characteristics in the prefrontal cortex tissues of ASD and unaffected individuals using RNA-sequencing data. Our results showed that most of the differentially expressed transposable elements belong to the Alu family, with 659 loci of Alu elements corresponding to 456 differentially expressed genes in the prefrontal cortex of ASD individuals. We predicted cis- and trans-regulation of Alu elements to host/distant genes by conducting correlation analyses. The expression level of Alu elements correlated significantly with 133 host genes (cis-regulation, adjusted p < 0.05) associated with ASD as well as the cell survival and cell death of neuronal cells. Transcription factor binding sites in the promoter regions of differentially expressed Alu elements are conserved and associated with autism candidate genes, including RORA. COBRA analyses of postmortem brain tissues showed significant hypomethylation in global methylation analyses of Alu elements in ASD subphenotypes as well as DNA methylation of Alu elements located near the RNF-135 gene (p < 0.05). In addition, we found that neuronal cell density, which was significantly increased (p = 0.042), correlated with the expression of genes associated with Alu elements in the prefrontal cortex of ASD. Finally, we determined a relationship between these findings and the ASD severity (i.e., ADI-R scores) of individuals with ASD. Our findings provide a better understanding of the impact of Alu elements on gene regulation and molecular neuropathology in the brain tissues of ASD individuals, which deserves further investigation.
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    Impact of gene polymorphisms involved in the vitamin D metabolic pathway on the susceptibility to and severity of autism spectrum disorder
    (2024-12-01) Saechua C.; Sarachana T.; Chonchaiya W.; Trairatvorakul P.; Yuwattana W.; Poolcharoen C.; Sangritdech M.; Saeliw T.; van Erp M.L.; Sangsuthum S.; Akarapredee N.; Tipnoppanon S.; Sukprasong R.; Satapornpong P.; Atasilp C.; Sukasem C.; Vanwong N.; Saechua C.; Mahidol University
    This study explores the association between genetic variations in the vitamin D pathway and autism spectrum disorder (ASD) susceptibility and severity in Thai children. A total of 276 participants, including 169 children with ASD and 107 healthy controls, were recruited. Genotyping of vitamin D pathway genes (CYP2R1, CYP27B1, GC, and VDR) was conducted using TaqMan-based real-time PCR, while serum vitamin D levels were measured by chemiluminescence immunoassay. ASD severity was assessed via the Childhood Autism Rating Scale, 2nd Edition. Results reveal that the VDR gene (ApaI) rs7975232 is linked to a reduced ASD risk. In contrast, the GC gene rs7041 (A > C) polymorphism shows a significant association with increased ASD risk and severity, particularly in individuals with both the GC gene polymorphism and vitamin D insufficiency. Additionally, there was a higher prevalence of the GC1s isoform and GC1s-GC1s haplotype in children with ASD, associated with ASD severity. This study identified that individuals possessing GC rs7041 C alleles and the GC1s genotype (rs7041C/rs4588G) exhibit an increased susceptibility to and more severity of ASD. Further studies with larger cohorts are essential to fully understand these genetic polymorphisms’ roles.
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    LINE-1 and Alu methylation signatures in autism spectrum disorder and their associations with the expression of autism-related genes
    (2022-12-01) Saeliw T.; Permpoon T.; Iadsee N.; Tencomnao T.; Hu V.W.; Sarachana T.; Green D.; Sae-Lee C.; Mahidol University
    Long interspersed nucleotide element-1 (LINE-1) and Alu elements are retrotransposons whose abilities cause abnormal gene expression and genomic instability. Several studies have focused on DNA methylation profiling of gene regions, but the locus-specific methylation of LINE-1 and Alu elements has not been identified in autism spectrum disorder (ASD). Here we interrogated locus- and family-specific methylation profiles of LINE-1 and Alu elements in ASD whole blood using publicly-available Illumina Infinium 450 K methylation datasets from heterogeneous ASD and ASD variants (Chromodomain Helicase DNA-binding 8 (CHD8) and 16p11.2del). Total DNA methylation of repetitive elements were notably hypomethylated exclusively in ASD with CHD8 variants. Methylation alteration in a family-specific manner including L1P, L1H, HAL, AluJ, and AluS families were observed in the heterogeneous ASD and ASD with CHD8 variants. Moreover, LINE-1 and Alu methylation within target genes is inversely related to the expression level in each ASD variant. The DNA methylation signatures of the LINE-1 and Alu elements in ASD whole blood, as well as their associations with the expression of ASD-related genes, have been identified. If confirmed in future larger studies, these findings may contribute to the identification of epigenomic biomarkers of ASD.
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    Neurological Effects of Cleistocalyx nervosum var. paniala Berry on Hippocampal Transcriptome, Neuritogenesis, and Synaptogenesis
    (2026-04-10) Kanlayaprasit S.; Parnich W.; Jantheang T.; Lertpeerapan P.; Panjabud P.; Kasitipradit K.; Poolcharoen C.; Saeliw T.; Muangnoi C.; Plaingam W.; Charoenkiatkul S.; Hu V.W.; Tencomnao T.; Sarachana T.; Sukprasansap M.; Kanlayaprasit S.; Mahidol University
    Background/Objectives: Neuritogenesis and synaptogenesis support learning and cognitive function, and hippocampal neurons play central roles in these processes. Cleistocalyx nervosum var. paniala (CNP), a Southeast Asian berry, has reported neuroprotective activities, but its direct effects on hippocampal neurons remain unclear. We investigated whether CNP extract modulates hippocampal neuronal transcriptomes, neuritogenesis, and synaptogenesis. Methods: Primary hippocampal neurons isolated from male and female Wistar rat pups were treated with CNP extract in vitro. Cytotoxicity was assessed to define non-cytotoxic concentrations. Transcriptomic responses were profiled by RNA sequencing and validated by RT-qPCR. Neuritogenesis was quantified by neurite morphology and Sholl analysis. Synaptogenesis was evaluated by synaptic immunocytochemistry. Molecular docking of cyanidin-3-glucoside (C3G) and resveratrol was used to generate mechanistic hypotheses. Results: At 0.1-10 µg/mL, CNP was non-cytotoxic, whereas a 100 µg/mL dose reduced viability; therefore, 10 µg/mL was used in subsequent experiments. Exploratory RNA-seq profiling identified thousands of differentially expressed genes enriched in synapse- and neurite-related pathways, including synaptogenesis signaling, axon guidance, and neuritogenesis. RT-qPCR showed upregulation of Igf1 in males and Glul in females, with sex-dependent modulation of Bdnf and Cask. CNP increased neurite length, branching, and Sholl complexity in both sexes, with a more pronounced effect in males. A male-biased effect was also observed in synapse-related marker colocalization, with increased Syn1-Psd95 colocalization detected in males. Docking suggested plausible interactions of C3G and resveratrol with regulators such as MYC, TP53, and CREB1. Conclusions: CNP extract alters transcriptional networks and enhances neurite outgrowth in primary hippocampal neurons in a sex-dependent manner, with male-biased effects on Syn1-Psd95 colocalization. These findings support further dose-response, mechanistic, and sex-stratified in vivo studies to evaluate its neurobiological potential.