👤 Tetsuro Miki

Brain-derived neurotrophic factor (BDNF) plays a critical role in neuronal development and synaptic plasticity across various maturation stages. However, the extent to which BDNF modulates the neuronal transcriptome to mediate these effects, and the gene clusters most responsive at each culture stage, remain poorly understood. To address this, we investigated the time-dependent effects of BDNF on the transcriptomes of cultured cortical neurons at different culture durations. We found that the magnitude of the transcriptomic response to a 6-h BDNF treatment, relative to untreated controls, increased with longer culture duration. Furthermore, a BDNF-induced shift towards a more mature-like transcriptional state was observed specifically in neurons cultured for shorter durations, suggesting a response dependent on the length of time in culture. Specifically, matrix metalloproteinase 3 (MMP3) was robustly induced by BDNF. Single-nucleus RNA sequencing (snRNA-seq) revealed that this induction was primarily localized to Lhx6-positive inhibitory neurons. Additionally, BDNF regulated the expression of various ligand and receptor genes through a combination of cell type-specific and non-specific mechanisms. These findings provide a comprehensive view of BDNF-mediated transcriptional regulation over the course of cortical neuron culture. Show less

Prenatal maternal depression is known to affect the neurodevelopment of offspring. This study aimed to investigate the profile of umbilical cord serum in mothers with major depressive disorder (MDD). Liquid chromatography-tandem mass spectrometry (LC-MS) was conducted using umbilical cord serum from mothers with MDD (n = 5) and controls (control, n = 5). The levels of several differentially expressed proteins in umbilical cord serum were compared between the MDD (n = 10) and control groups (n = 10) by enzyme-linked immunosorbent assay. The proteomic profiles in the umbilical cord serum were different between the MDD and control groups, including the pathways of regulation of plasma lipoprotein particle levels, and synapse organization. Only apolipoprotein A4 (APOA4) was significantly higher in the cord blood of MDD group. APOA4 levels in maternal serum were also significantly higher in the MDD group than those in the control group. The APOA4 levels in the umbilical cord serum were higher than that in the maternal serum. The levels of APOA4, a biomarker of depression, in the umbilical cord serum at birth were elevated in the neonates of MDD mothers. It is, therefore, likely that fetuses of MDD mothers were exposed to higher APOA4 levels in utero and this could have developmental and mental health implications for the offspring. Show less

Engineered cardiac tissue (ECT) using human induced pluripotent stem cell-derived cardiomyocytes is a promising tool for modeling heart disease. However, tissue immaturity makes robust disease modeling difficult. Here, we established a method for modeling hypertrophic cardiomyopathy (HCM) malignant (MYH7 R719Q) and nonmalignant (MYBPC3 G115 Show less

Age-related macular degeneration (AMD) is a major cause of blindness in the elderly. Previous sequencing studies of AMD susceptibility genes have revealed the association of rare coding variants in CFH, CFI, C3 and C9 in European population; however, the impact of rare or low-frequency coding variants on AMD susceptibility in other populations is largely unknown. To identify the role of low-frequency coding variants on exudative AMD susceptibility in a Japanese population, we analysed the association of coding variants of 34 AMD candidate genes in the two-stage design by a multiplex PCR-based target sequencing method. We used a total of 2,886 (1st: 827, 2nd: 2,059) exudative AMD cases including typical AMD, polypoidal choroidal vasculopathy, and retinal angiomatous proliferation and 9,337 (1st: 3,247 2nd: 6,090) controls. Gene-based analysis found a significant association of low-frequency variants (minor allele frequency (MAF) < 0.05) in CETP, C2 and CFB. The association of CETP remained after conditioned with all known genome-wide association study (GWAS) associated variants. In addition, when we included only disruptive variants, enrichment of rare variants (MAF < 0.01) was also observed after conditioned with all GWAS associated variants (P = 1.03 × 10−6, odds ratio (OR) = 2.48). Haplotype and conditional analysis of the C2-CFB-SKIV2L locus showed a low-frequency variant (R74H) in CFB would be individually associated with AMD susceptibility independent of the GWAS associated SNP. These findings highlight the importance of target sequencing to reveal the impact of rare or low-frequency coding variants on disease susceptibility in different ethnic populations. Show less

Risk stratification of Brugada syndrome (BrS) remains controversial and the majority of patients with BrS have no genetic explanation. We investigated relationships between genotypes of 3 single-nucleotide polymorphisms reported in a recent genome-wide association study and BrS phenotypes. SCN10A (rs10428132), SCN5A (rs11708996), and downstream from HEY2 (rs9388451) single-nucleotide polymorphisms were genotyped and compared between 95 Japanese patients with BrS and 1978 controls. Relationships between the single-nucleotide polymorphisms and clinical characteristics, 12-lead ECG findings, signal-averaged ECG findings, and electrophysiological parameters were also examined in patients with BrS. Both rs10428132 and rs9388451 were significantly associated with BrS (P=2.7×10(-14); odds ratio, 3.0; P=9.2×10(-4); odds ratio, 1.7, respectively). Interestingly, the HEY2 risk allele C was less frequent in BrS patients with ventricular fibrillation than in those without (59% versus 74%; P=4.1×10(-2); odds ratio, 0.5). A significant linear correlation was found between HEY2 genotypes and QTc interval (CC: 422±27 ms; CT: 408±21 ms; and TT: 381±27 ms; P= 4.0×10(-4)). The HEY2 mRNA expression level in the right ventricular specimens from patients with BrS (n=20) was significantly lower in patients with CC genotype than the other genotypes (P=0.04). Additionally, during 63±28 months follow-up periods after implantable cardioverter defibrillator implantation (n=90), Kaplan-Meier event-free survival curves revealed that the cumulative rate of ventricular fibrillation events was significantly lower in cases with HEY2 CC genotype (P=0.04). Our findings suggest that HEY2 CC genotype may be a favorable prognostic marker for BrS, protectively acting to prevent ventricular fibrillation presumably by regulating the repolarization current. Show less

Multiple genetic loci associated with obesity or body mass index (BMI) have been identified through genome-wide association studies conducted predominantly in populations of European ancestry. We performed a meta-analysis of associations between BMI and approximately 2.4 million SNPs in 27,715 east Asians, which was followed by in silico and de novo replication studies in 37,691 and 17,642 additional east Asians, respectively. We identified ten BMI-associated loci at genome-wide significance (P < 5.0 × 10(-8)), including seven previously identified loci (FTO, SEC16B, MC4R, GIPR-QPCTL, ADCY3-DNAJC27, BDNF and MAP2K5) and three novel loci in or near the CDKAL1, PCSK1 and GP2 genes. Three additional loci nearly reached the genome-wide significance threshold, including two previously identified loci in the GNPDA2 and TFAP2B genes and a newly identified signal near PAX6, all of which were associated with BMI with P < 5.0 × 10(-7). Findings from this study may shed light on new pathways involved in obesity and demonstrate the value of conducting genetic studies in non-European populations. Show less

17beta-hydroxysteroid dehydrogenase type 12 (17beta-HSD12) has been demonstrated to be involved in enzymatic conversion of weak estrogen, estrone to more potent one, estradiol. However, this enzyme was also reported to be involved in an elongation of very long chain fatty acid (VLCFA). Many genes involved in lipid metabolism are regulated by the transcription factor termed sterol regulatory element-binding proteins (SREBPs). Results of our present study demonstrated that the existence of putative SRE sequence which is recognized as responsive element for SREBPs in 5'-flanking region of 17beta-HSD12 gene. Results of luciferase assay demonstrated that the transcriptional activity of this SRE sequence depends on the activation of SREBP-1 in HepG2 (hepatocellular carcinoma cell line, human) and SK-BR-3 (breast carcinoma cell line, human). 17beta-HSD12 expression was also induced in the HepG2 cells treated with the absence of sterols in which SREBPs were activated. All these results obtained in this study clearly indicate that SREBP-1 represents one of the transcriptional regulators of human 17beta-HSD12. Show less

17beta-Hydroxysteroid dehydrogenase type 12 (17beta-HSD12) has been shown to be involved in elongation of very long chain fatty acid (VLCFA) as well as in biosynthesis of estradiol (E2). 17beta-HSD12 expression was also reported in breast carcinomas but its functions have remained unknown. In this study, we examined the correlation between mRNA expression profiles determined by microarray analysis and tissue E2 concentrations obtained from 16 postmenopausal breast carcinoma cases. No significant correlations were detected between 17beta-HSD12 expression and E2 concentration. We then immunolocalized this enzyme in 110 cases of invasive ductal carcinoma. 17beta-HSD12 immunoreactivity in breast carcinoma cells was significantly associated with poor prognosis of the patients. We further examined the biological significance of 17beta-HSD12 using cell-based studies. Small interfering RNA-mediated knockdown of 17beta-HSD12 in SK-BR-3 (estrogen receptor-negative breast carcinoma cell line) resulted in significant growth inhibition, which was recovered by the addition of VLCFAs such as arachidonic acid. The status of 17beta-HSD12 immunoreactivity was also correlated with adverse clinical outcome in cyclooxygenase 2 (COX2)-positive breast cancer patients but not in COX2-negative patients. Therefore, these findings indicated that 17beta-HSD12 was not necessarily related to intratumoral E2 biosynthesis, at least in human breast carcinoma, but was rather correlated with production of VLCFAs such as arachidonic acid, which may subsequently be metabolized to prostaglandins by COX2 and result in tumor progression of the patients. Show less

The 17beta-hydroxysteroid dehydrogenases (HSDs) are enzymes that catalyze the reduction of 17-ketosteroids or the oxidation of 17beta-hydroxysteroids. 17beta-HSD type 12, the most recently cloned member of this gene family, was classified into the 17beta-HSD family based on sequence homology, rather than steroid catalyzing activity. Meanwhile, it has been reported that 17beta-HSD type 12 may be involved in fatty acid synthesis. To better understand the role of 17beta-HSD type 12 in lipid metabolism, we determined the detailed systemic distribution and tissue localizations of 17beta-HSD type 12, which, due partly to the lack of antibodies, had not yet been studied. We carried out these investigations by quantitative reverse transcription (RT)-PCR, Northern blot analysis, and immunohistochemistry, using an antibody against 17beta-HSD type 12 that we have generated. 17beta-HSD type 12 is highly expressed in organs related to lipid metabolism such as liver, kidney, heart and skeletal muscle. 17beta-HSD type 12 is also detected in endocrine-related organs such as pancreas, pituitary gland, adrenal gland, testis and placenta, and in the gastrointestinal tract, which point to the possible involvement of 17beta-HSD type 12 in the regulation of lipid biosynthesis and steroid metabolism. These results support previous reports and solidify the possibility that 17beta-HSD type 12 may play critical roles in the physiological processes, such as fatty acid synthesis, in addition to the steroid metabolism. Show less