Motoko Maekawa

Schizophrenia is a severe neurodevelopmental disorder whose etiology remains incompletely understood. Epidemiological studies of the Dutch Hunger Winter demonstrated that maternal famine during early gestation increased the risk of schizophrenia in offspring, implicating the Developmental Origins of Health and Disease (DOHaD) framework. However, the molecular mechanisms underlying this association remain unclear. Here, we developed a novel DOHaD-based schizophrenia model by subjecting pregnant mice to transient fasting restricted to the peri-implantation period, a critical window of global epigenomic reprogramming. Male offspring of fasted dams exhibited schizophrenia-related phenotypes, including impaired sensorimotor gating, abnormal behavioral patterns, and reduced dendritic spine density in the medial prefrontal cortex. Multi-omics profiling, integrating bulk RNA sequencing, Visium HD spatial transcriptomics, and DNA methylation arrays, revealed convergent alterations in synaptic organization, protein homeostasis, and oxidative stress pathways. These findings highlight how brief maternal fasting reprograms the epigenome and reshapes neural circuitry. Our work establishes the first animal model that directly mirrors early gestational famine exposure linked to schizophrenia risk, providing a unique platform for uncovering epigenetic mechanisms underlying the developmental origins of psychiatric disorders.

Epidemiological studies have identified high-fat diet (HFD)-induced obesity as a risk factor for Alzheimer's disease (AD), yet the underlying molecular mechanisms remain inadequately elucidated. Microglia, the brain’s innate immune cells, are pivotal in AD brain by engulfing β-amyloid (Aβ) peptides and compacting poorly consolidated Aβ plaques. Microglia are highly susceptible to the metabolic milieu; however, it is unclear how long-term HFD alters the lipid environment and influences microglial phenotype in AD brains. In this study, APP ^NL−G−F knock-in AD model mice were fed an HFD for 9–27 weeks and subsequently analyzed for Aβ pathology and microglial function. Our findings indicated that HFD intake accelerated Aβ deposition, attenuated the recruitment of microglia to the plaques and impaired their phagocytic activity, while also promoting the accumulation of intracellular lipid droplets (LDs). Lipidomic analyses revealed that HFD, in synergy with AD pathology, increased the proportion of cholesterol esters in the cerebral cortex. In vitro, oleic acid—a major HFD constituent—similarly diminished the phagocytic capacity of MG6 microglia and induced LDs accumulation, along with downregulation of gene sets of cholesterol efflux, phagocytosis and engulfment. Overall, these findings implied that HFD-induced perturbation in brain cholesterol homeostasis may compromise microglial activation and expedite AD progression in APP ^NL−G−F mice.

Aims: Fatty acid binding protein 4, adipocyte ( Fabp4 ), is well known for its role in peripheral lipid metabolism, but its potential role in brain function remains largely unexplored. This study aimed to investigate Fabp4 expression in the adult mouse brain and explore gene expression changes in Fabp4 knockout (KO) mice to assess its potential impact on brain function. Methods: We conducted in situ hybridization to assess Fabp4 expression in key brain regions of adult mice. In parallel, differential gene expression analysis using RNA‐seq was conducted in the prefrontal cortex of Fabp4 KO mice to identify genes affected by Fabp4 deficiency. Results: No Fabp4 expression was detected in the brains of mice, suggesting a lack of direct involvement in the central nervous system. However, Fabp4 KO mice exhibited significant changes in gene expression in the brain, with 31 genes upregulated and 30 downregulated. Downregulated genes were linked to histone methylation and metabolic processes, while upregulated ones were associated with synaptic organization. Conclusion: Although Fabp4 is not expressed in the brain, its deficiency leads to substantial changes in gene expression, likely mediated by peripheral metabolic pathways and epigenetic regulation. These changes may explain the previously observed autism‐like behaviors and increased dendritic spine density in Fabp4 KO mice. This study sheds light on the role of systemic lipid metabolism in neurodevelopmental disorders such as autism spectrum disorder (ASD) and highlights epigenetic mechanisms as potential mediators of these effects.

Structural changes in the corpus callosum have been reported in schizophrenia; however, the underlying molecular mechanism remains unclear. As the corpus callosum is high in lipid content, we analyzed the lipid contents of the corpora callosa from 15 patients with schizophrenia and 15 age- and sex-matched controls using liquid chromatography coupled to tandem mass spectrometry and identified lipid combinations associated with schizophrenia. Real-time quantitative polymerase chain reaction analyses using extended samples (schizophrenia, n = 95; control, n = 91) showed low expression levels of lipid metabolism-related genes and their potential upstream transcription factors in schizophrenia. Subsequent pathway analysis identified a gene regulatory network where nuclear factor of activated T cells 2 (NFATC2) is placed most upstream. We also observed low gene expression levels of microglial markers, inflammatory cytokines, and colony-stimulating factor 1 receptor (CSF1R), which is known to regulate the density of microglia, in the corpus callosum in schizophrenia. The interactions between CSF1R and several genes in the presently identified gene network originating from NFATC2 have been reported. Collectively, this study provides evidence regarding lipid abnormalities in the corpora callosa of patients with schizophrenia and proposes the potential role of impaired “NFATC2-relevant gene network-microglial axis” as its underlying mechanism.

Autism spectrum disorder is a neurodevelopmental disorder characterized by difficulties in social communication and interaction, as well as repetitive and characteristic patterns of behaviour. Although the pathogenesis of autism spectrum disorder is unknown, being overweight or obesity during infancy and low weight at birth are known as risks, suggesting a metabolic aspect. In this study, we investigated adipose tissue development as a pathophysiological factor of autism spectrum disorder by examining the serum levels of adipokines and other metabolic markers in autism spectrum disorder children (n = 123) and typically developing children (n = 92) at 4–12 years of age. Among multiple measures exhibiting age-dependent trajectories, the leptin levels displayed different trajectory patterns between autism spectrum disorder and typically developing children, supporting an adipose tissue-dependent mechanism of autism spectrum disorder. Of particular interest, the levels of fatty acid binding protein 4 (FABP4) were significantly lower in autism spectrum disorder children than in typically developing subjects, at preschool age (4–6 years old: n = 21 for autism spectrum disorder and n = 26 for typically developing). The receiver operating characteristic curve analysis discriminated autism spectrum disorder children from typically developing children with a sensitivity of 94.4% and a specificity of 75.0%. We re-sequenced the exons of the FABP4 gene in a Japanese cohort comprising 659 autism spectrum disorder and 1000 control samples, and identified two rare functional variants in the autism spectrum disorder group. The Trp98Stop, one of the two variants, was transmitted to the proband from his mother with a history of depression. The disruption of the Fabp4 gene in mice evoked autism spectrum disorder-like behavioural phenotypes and increased spine density on apical dendrites of pyramidal neurons, which has been observed in the postmortem brains of autism spectrum disorder subjects. The Fabp4 knockout mice had an altered fatty acid composition in the cortex. Collectively, these results suggest that an ‘adipo-brain axis’ may underlie the pathophysiology of autism spectrum disorder, with FABP4 as a potential molecule for use as a biomarker.