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SummaryGamma-aminobutyric acid (GABA) is the main inhibitory neurotransmitter in adults. Depolarizing GABA responses have been well characterized at neuronal-population average level during typical neurodevelopment and partially in brain disorders. However, no investigation has specifically assessed whether a mosaicism of cells with either depolarizing or hyperpolarizing/inhibitory GABAergic responses exists in animals in health/disease at diverse developmental stages, including adulthood. Here, we showed that such mosaicism is present in wild-type (WT) and down syndrome (DS) neuronal networks, as assessed at increasing scales of complexity (cultures, brain slices, behaving mice). Nevertheless, WT mice presented a much lower percentage of cells with depolarizing GABA than DS mice. Restoring the mosaicism of hyperpolarizing and depolarizing GABA-responding neurons to WT levels rescued anxiety behavior in DS mice. Moreover, we found heterogeneous GABAergic responses in developed control and trisomic human induced-pluripotent-stem-cells-derived neurons. Thus, a heterogeneous subpopulation of GABA-responding cells exists in physiological/pathological conditions in mouse and human neurons, possibly contributing to disease-associated behaviors. Graphical abstract Highlights•Subpopulations of GABAAR-responding neurons exist in mouse and human neuronal networks•DS networks exhibit a larger fraction of neurons with depolarizing GABA responses•Restoring physiological GABA-mediated inhibition rescues anxiety behavior in DS mice•Heterogeneous GABAergic responses coexist in control and DS human iPSC neurons Behavioral neuroscience; Developmental neuroscience; Cellular neuroscience

Arterioles are small blood vessels located just upstream of capillaries in nearly all tissues. Despite the broad and essential role of arterioles in physiology and disease, current knowledge of the functional genomics of arterioles is largely absent. Here, we report extensive maps of chromatin interactions, single-cell expression, and other molecular features in human arterioles and uncover mechanisms linking human genetic variants to gene expression in vascular cells and the development of hypertension. Compared to large arteries, arterioles exhibited a higher proportion of pericytes which were enriched for blood pressure (BP)-associated genes. BP-associated single nucleotide polymorphisms (SNPs) were enriched in chromatin interaction regions in arterioles. We linked BP-associated noncoding SNP rs1882961 to gene expression through long-range chromatin contacts and revealed remarkable effects of a 4-bp noncoding genomic segment on hypertension in vivo. We anticipate that our data and findings will advance the study of the numerous diseases involving arterioles. Liu et al., report extensive maps of chromatin interactions, single-cell expression, and other molecular features in human arterioles and uncover mechanisms linking noncoding genetic variants to gene expression and the development of hypertension.

AbstractBackgroundOXA1L is crucial for mitochondrial protein insertion and assembly into the inner mitochondrial membrane, and its variants have been recently linked to mitochondrial encephalopathy. However, the definitive pathogenic link between OXA1L variants and mitochondrial diseases as well as the underlying pathogenesis remains elusive.MethodsIn this study, we identified bi?allelic variants of c.620G>T, p.(Cys207Phe) and c.1163_1164del, p.(Val388Alafs*15) in OXA1L gene in a mitochondrial myopathy patient using whole exome sequencing. To unravel the genotype–phenotype relationship and underlying pathogenic mechanism between OXA1L variants and mitochondrial diseases, patient?specific human?induced pluripotent stem cells (hiPSC) were reprogrammed and differentiated into myotubes, while OXA1L knockout human immortalised skeletal muscle cells (IHSMC) and a conditional skeletal muscle knockout mouse model was generated using clustered regularly interspaced short palindromic repeats/Cas9 genomic editing technology.ResultsBoth patient?specific hiPSC differentiated myotubes and OXA1L knockout IHSMC showed combined mitochondrial respiratory chain defects and oxidative phosphorylation (OXPHOS) impairments. Notably, in OXA1L?knockout IHSMC, transfection of wild?type human OXA1L but not truncated mutant form rescued the respiratory chain defects. Moreover, skeletal muscle conditional Oxa1l knockout mice exhibited OXPHOS deficiencies and skeletal muscle morphofunctional abnormalities, recapitulating the phenotypes of mitochondrial myopathy. Further functional investigations revealed that impaired OXPHOS resulting of OXA1L deficiency led to elevated reactive oxygen species production, which possibly activated the nuclear factor kappa B signalling pathway, triggering cell apoptosis.ConclusionsTogether, our findings reinforce the genotype–phenotype association between OXA1L variations and mitochondrial diseases and further delineate the potential molecular mechanisms of how OXA1L deficiency causes skeletal muscle deficits in mitochondrial myopathy.Keypoints OXA1L gene bi?allelic variants cause mitochondrial myopathy.OXA1L deficiency results in combined mitochondrial respiratory chain defects and OXPHOS impairments.OXA1L deficiency leads to elevated ROS production, which may activate the NF??B signalling pathway, disturbing myogenic gene expression and triggering cell apoptosis. OXA1L gene bi?allelic variants cause mitochondrial myopathy.OXA1L deficiency results in combined mitochondrial respiratory chain defects and OXPHOS impairments.OXA1L deficiency leads to elevated ROS production, which may activate the NF??B signalling pathway, disturbing myogenic gene expression and triggering cell apoptosis.

Aging of the brain vasculature plays a key role in the development of neurovascular and neurodegenerative diseases, thereby contributing to cognitive impairment. Among other factors, DNA damage strongly promotes cellular aging, however, the role of genomic instability in brain endothelial cells (EC) and its potential effect on brain homeostasis is still largely unclear. We here investigated how endothelial aging impacts blood-brain barrier (BBB) function by using excision repair cross complementation group 1 (ERCC1)-deficient human brain ECs and an EC-specific Ercc1 knock out (EC-KO) mouse model. In vitro, ERCC1-deficient brain ECs displayed increased senescence-associated secretory phenotype expression, reduced BBB integrity, and higher sprouting capacities due to an underlying dysregulation of the Dll4-Notch pathway. In line, EC-KO mice showed more P21+ cells, augmented expression of angiogenic markers, and a concomitant increase in the number of brain ECs and pericytes. Moreover, EC-KO mice displayed BBB leakage and enhanced cell adhesion molecule expression accompanied by peripheral immune cell infiltration into the brain. These findings were confined to the white matter, suggesting a regional susceptibility. Collectively, our results underline the role of endothelial aging as a driver of impaired BBB function, endothelial sprouting, and increased immune cell migration into the brain, thereby contributing to impaired brain homeostasis as observed during the aging process.

BackgroundUnderstanding the lineage differentiation of human prostate not only is crucial for basic research on human developmental biology but also significantly contributes to the management of prostate-related disorders. Current knowledge mainly relies on studies on rodent models, lacking human-derived alternatives despite clinical samples may provide a snapshot at certain stage. Human embryonic stem cells can generate all the embryonic lineages including the prostate, and indeed a few studies demonstrate such possibility based on co-culture or co-transplantation with urogenital mesenchyme into mouse renal capsule.MethodsTo establish a stepwise protocol to obtain prostatic organoids in vitro from human embryonic stem cells, we apply chemicals and growth factors by mimicking the regulation network of transcription factors and signal transduction pathways, and construct cell lines carrying an inducible NKX3-1 expressing cassette, together with three-dimensional culture system. Unpaired t test was applied for statistical analyses.ResultsWe first successfully generate the definitive endoderm, hindgut, and urogenital sinus cells. The embryonic stem cell-derived urogenital sinus cells express prostatic key transcription factors AR and FOXA1, but fail to express NKX3-1. Therefore, we construct NKX3-1-inducible cell line by homologous recombination, which is eventually able to yield AR, FOXA1, and NKX3-1 triple-positive urogenital prostatic lineage cells through stepwise differentiation. Finally, combined with 3D culture we successfully derive prostate-like organoids with certain structures and prostatic cell populations.ConclusionsThis study reveals the crucial role of NKX3-1 in prostatic differentiation and offers the inducible NKX3-1 cell line, as well as provides a stepwise differentiation protocol to generate human prostate-like organoids, which should facilitate the studies on prostate development and disease pathogenesis.Supplementary InformationThe online version contains supplementary material available at 10.1186/s13287-024-03886-y.

SummaryNGN2-driven induced pluripotent stem cell (iPSC)-to-neuron conversion is a popular method for human neurological disease modeling. In this study, we present a standardized approach for generating neurons utilizing clonal, targeted-engineered iPSC lines with defined reagents. We demonstrate consistent production of excitatory neurons at scale and long-term maintenance for at least 150 days. Temporal omics, electrophysiological, and morphological profiling indicate continued maturation to postnatal-like neurons. Quantitative characterizations through transcriptomic, imaging, and functional assays reveal coordinated actions of multiple pathways that drive neuronal maturation. We also show the expression of disease-related genes in these neurons to demonstrate the relevance of our protocol for modeling neurological disorders. Finally, we demonstrate efficient generation of NGN2-integrated iPSC lines. These workflows, profiling data, and functional characterizations enable the development of reproducible human in vitro models of neurological disorders. Graphical abstract Highlights•Optimized NGN2 protocol generates functional postnatal neurons in 28 days•Extensive profiling data provide benchmarks for neuron maturation•Maturation assays reliably assess neuron maturation in single or mixed cell types•Rapid targeted engineering protocol integrates NGN2 into iPSC lines in 3 weeks MotivationUsing induced pluripotent stem cell (iPSC)-derived neurons (iNs) to model diseases requires defined, robust, and reproducible protocols capable of generating predictable neuronal types. In addition, extensive profiling is essential to assess whether iNs are suitable to model specific diseases with desired molecular, functional, and maturation-related features. We sought to establish a standardized protocol for generating iNs at large scales. We also sought to develop systematic profiling data and assays for determining the maturation levels of iN cultures as resources for the community. Shan et al. report methods to generate postnatal-like iPSC-derived neurons at large scale and with long-term stability. They provide extensive characterization data and assays to measure neuronal maturity. They find genes associated with maturation exhibit diverse functions. Their data support the utility of these methods to enable modeling of neurological disorders.