👤 Tomohiko Taki

Microglia, the resident immune cells of the central nervous system (CNS), play a pivotal role in health and disease maintaining homeostasis and mediating neuroinflammatory responses. Their activation is a dynamic and context-dependent process characterized by diverse phenotypic states defined by transcriptomic, proteomic, and morphological characteristics. While lipopolysaccharide (LPS) is widely used as an inflammatory stimulus in microglial research, its physiological relevance remains debated. Interferon gamma (IFNγ), a key pro-inflammatory cytokine involved in immune priming, more closely mimics CNS inflammatory conditions. In this study, we systematically investigated the temporal activation profiles of human iPSC-derived microglia (hiMG) in response to LPS, IFNγ, and their combination. Transcriptomic analysis at 24 h revealed robust differential gene expression, with over 7,000 genes altered by LPS and more than 8,500 by LPS/IFNγ co-stimulation. These profiles partially overlapped with disease-associated microglia (DAM) signatures, including upregulation of Show less

We demonstrated that low-intensity pulsed ultrasound (LIPUS) therapy tended to ameliorate cognitive declines in patients with early Alzheimer's disease (AD) in the pilot trial. Thus, we have started the pivotal trial in a randomized, double-blind, placebo-controlled manner (LIPUS-AD). We here report the clinical characteristics of AD patients enrolled in the trial. The major inclusion criteria included age 50-90 years of both sex, Clinical Dementia Rating (CDR) global score of 0.5∼1.0 and Japanese version of the Mini-Mental State Examination (MMSE-J) score greater than 20 at screening, positive brain Aβ-PET, and no symptomatic brain hemorrhage, infarction, or edema on brain MRI. A total of 231 subjects were finally enrolled. As compared with the pilot trial, they were characterized by older age and higher prevalence of dyslipidemia. They had lower scores of ADAS-J-cog and Modified Hachinski Ischemic Scale (MHIS), while other cognitive scores were comparable with the pilot trial. Use of cholinesterase inhibitors was less as compared with the pilot trial. Clinical characteristics of subjects in the LIPUS-AD trial largely mimic those in the pilot trial, addressing efficacy and safety of the LIPUS therapy in early AD.Clinical Trial Gov. No.: NCT05983575, jRCT No.: jRCT2032230125. Show less

Expression of intragenic exon rearrangements (IERs) has reportedly been detected in both normal and cancer cells. However, there have been few reports of occurrence of these rearrangements specific to neoplasms including malignant lymphoma. In this study, we detected IERs of ten genes (NBPF8, SOBP, AUTS2, RAB21, SPATA13, ABCC4, WDR7, PHLPP1, NFATC1 and MAGED1) in non-Hodgkin B cell lymphoma (B-NHL) cell line KPUM-UH1 using a high-resolution single nucleotide polymorphism array and reverse transcription polymerase chain reaction using reversely directed divergent primers within exons involved in genomic intragenic gains followed by sequencing analysis. Among them, the IERs involved in SOBP (6q21) exon 2 and 3 and AUTS2 (7q11.22) exon 2-4 were the molecular lesions specific to tumors and were frequently detected in B-NHL samples. These IERs constitute novel genetic alterations of B-NHL, which might be associated with tumorigenesis and be useful as genetic biological markers. Show less

Recent advances in the genetic understanding of acute myeloid leukemia (AML) have improved clinical outcomes in pediatric patients. However, ∼40% of patients with pediatric AML relapse, resulting in a relatively low overall survival rate of ∼70%. The objective of this study was to reveal the comprehensive genetic background of pediatric AML. We performed transcriptome analysis (RNA sequencing [RNA-seq]) in 139 of the 369 patients with de novo pediatric AML who were enrolled in the Japanese Pediatric Leukemia/Lymphoma Study Group AML-05 trial and investigated correlations between genetic aberrations and clinical information. Using RNA-seq, we identified 54 in-frame gene fusions and 1 RUNX1 out-of-frame fusion in 53 of 139 patients. Moreover, we found at least 258 gene fusions in 369 patients (70%) through reverse transcription polymerase chain reaction and RNA-seq. Five gene rearrangements were newly identified, namely, NPM1-CCDC28A, TRIP12-NPM1, MLLT10-DNAJC1, TBL1XR1-RARB, and RUNX1-FNBP1. In addition, we found rare gene rearrangements, namely, MYB-GATA1, NPM1-MLF1, ETV6-NCOA2, ETV6-MECOM, ETV6-CTNNB1, RUNX1-PRDM16, RUNX1-CBFA2T2, and RUNX1-CBFA2T3. Among the remaining 111 patients, KMT2A-PTD, biallelic CEBPA, and NPM1 gene mutations were found in 11, 23, and 17 patients, respectively. These mutations were completely mutually exclusive with any gene fusions. RNA-seq unmasked the complexity of gene rearrangements and mutations in pediatric AML. We identified potentially disease-causing alterations in nearly all patients with AML, including novel gene fusions. Our results indicated that a subset of patients with pediatric AML represent a distinct entity that may be discriminated from their adult counterparts. Based on these results, risk stratification should be reconsidered. Show less

The recurrent translocation t(10;11) is associated with acute myeloid leukemia (AML). The AF10 gene on chromosome 10 at band p12 and MLL at 11q23 fuse in the t(10;11)(p12;q23). Recently, we have identified ABI1 as a new partner gene for MLL in an AML patient with a t(10;11)(p11.2;q23). The ABI1 is a human homologue of the mouse Abl-interactor 1 (Abi1), encoding an Abl-binding protein. The ABI1 protein exhibits sequence similarity to homeotic genes, and contains several polyproline stretches and a src homology 3 (SH3) domain. To clarify the clinical features of t(10;11)-leukemias, we investigated 6 samples from acute leukemia patients with t(10;11) and MLL rearrangement and detected MLL-AF10 chimeric transcripts in 5 samples and MLL-ABI1 in one. The patient with MLL-ABI1 chimeric transcript is the second case described, thus confirming that the fusion of the MLL and ABI1 genes is a recurring abnormality. Both of the patients with MLL-ABI1 chimeric transcript are surviving, suggesting that these patients have a better prognosis than the patients with MLL-AF10. To investigate the roles of AF10 and ABI1 further, we examined the expression of these genes in various cell lines and fresh tumor samples using the reverse transcriptase-polymerase chain reaction method. Although AF10 was expressed in almost all cell lines similarly, the expression patterns of ABI1 were different between leukemia and solid tumor cell lines, suggesting the distinctive role of each isoform of ABI1 in these cell lines. We also determined the complete mouse Abi1 sequence and found that the sequence matched with human ABI1 better than the originally reported Abi1 sequence. Further functional analysis of the MLL-AF10 and MLL-ABI1 fusion proteins will provide new insights into the leukemogenesis of t(10;11)-AML. Show less