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Background: Extracellular vesicles (EVs) hold the potential for elucidating the pathogenesis of amyotrophic lateral sclerosis (ALS) and serve as biomarkers. Notably, the comparative and longitudinal alterations in the protein profiles of EVs in serum (sEVs) and cerebrospinal fluid (CSF; cEVs) of sporadic ALS (SALS) patients remain uncharted. Ropinirole hydrochloride (ROPI; dopamine D2 receptor [D2R] agonist), a new anti-ALS drug candidate identified through induced pluripotent stem cell (iPSC)-based drug discovery, has been suggested to inhibit ALS disease progression in the Ropinirole Hydrochloride Remedy for Amyotrophic Lateral Sclerosis (ROPALS) trial, but its mechanism of action is not well understood. Therefore, we tried to reveal longitudinal changes with disease progression and the effects of ROPI on protein profiles of EVs., Methods: We collected serum and CSF at fixed intervals from ten controls and from 20 SALS patients participating in the ROPALS trial. Comprehensive proteomic analysis of EVs, extracted from these samples, was conducted using liquid chromatography/mass spectrometer (LC/MS). Furthermore, we generated iPSC-derived astrocytes (iPasts) and performed RNA sequencing on astrocytes with or without ROPI treatment., Results: The findings revealed notable disparities yet high congruity in sEVs and cEVs protein profiles concerning disease status, time and ROPI administration. In SALS, both sEVs and cEVs presented elevated levels of inflammation-related proteins but reduced levels associated with unfolded protein response (UPR). These results mirrored the longitudinal changes after disease onset and correlated with the revised ALS Functional Rating Scale (ALSFRS-R) at sampling time, suggesting a link to the onset and progression of SALS. ROPI appeared to counteract these changes, attenuating inflammation-related protein levels and boosting those tied to UPR in SALS, proposing an anti-ALS impact on EV protein profiles. Reverse translational research using iPasts indicated that these changes may partly reflect the DRD2-dependent neuroinflammatory inhibitory effects of ROPI. We have also identified biomarkers that predict diagnosis and disease progression by machine learning-driven biomarker search., Conclusions: Despite the limited sample size, this study pioneers in reporting time-series proteomic alterations in serum and CSF EVs from SALS patients, offering comprehensive insights into SALS pathogenesis, ROPI-induced changes, and potential prognostic and diagnostic biomarkers., (© 2024. The Author(s).)

Inflammatory responses are known to suppress neural regeneration in patients receiving stem cell-based regenerative therapy for spinal cord injury (SCI). Consequently, pathways involved in neurogenesis and immunomodulation, such as the hepatocyte growth factor (HGF)/MET signaling cascade, have garnered significant attention. Notably, various studies, including our own, have highlighted the enhanced recovery of locomotor functions achieved in SCI animal models by combining HGF pretreatment and human induced stem cell-derived neural stem/progenitor cell (hiPSC-NS/PC) transplantation. However, these studies implicitly hypothesized that the functionality of HGF in SCI would be time consistent and did not elucidate its dynamics. In the present article, we investigated the time-course of the effect of HGF on SCI, aiming to uncover a more precise mechanism for HGF administration, which is indispensable for developing crystallizing protocols for combination therapy. To this end, we performed a detailed investigation of the temporal variation of HGF using the RNA-seq data we obtained in our most recent study. Leveraging the time-series design of the data, which we did not fully exploit previously, we identified three components in the effects of HGF that operate at different times: early effects, continuous effects, and delayed effects. Our findings suggested a concept where the three components together contribute to the acceleration of neurogenesis and immunomodulation, which reinforce the legitimacy of empirically fine-tuned protocols for HGF administration and advocate the novel possibility that the time-inconsistent effects of HGF progressively augment the efficacy of combined therapy., (© 2024. The Author(s).)

Background: The development of induced pluripotent stem cells (iPSCs) technology has enabled human cellular disease modeling for inaccessible cell types, such as neural cells in the brain. However, many of the iPSC-derived disease models established to date typically involve only a single cell type. These monoculture models are inadequate for accurately simulating the brain environment, where multiple cell types interact. The limited cell type diversity in monoculture models hinders the accurate recapitulation of disease phenotypes resulting from interactions between different cell types. Therefore, our goal was to create cell models that include multiple interacting cell types to better recapitulate disease phenotypes., Methods: To establish a co-culture model of neurons and astrocytes, we individually induced neurons and astrocytes from the same iPSCs using our novel differentiation methods, and then co-cultured them. We evaluated the effects of co-culture on neurons and astrocytes using immunocytochemistry, immuno-electron microscopy, and Ca 2+ imaging. We also developed a co-culture model using iPSCs from a patient with familial Alzheimer's disease (AD) patient (APP V717L mutation) to investigate whether this model would manifest disease phenotypes not seen in the monoculture models., Results: The co-culture of the neurons and astrocytes increased the branching of astrocyte processes, the number of GFAP-positive cells, neuronal activities, the number of synapses, and the density of presynaptic vesicles. In addition, immuno-electron microscopy confirmed the formation of a tripartite synaptic structure in the co-culture model, and inhibition of glutamate transporters increased neuronal activity. Compared to the co-culture model of the control iPSCs, the co-culture model of familial AD developed astrogliosis-like phenotype, which was not observed in the monoculture model of astrocytes., Conclusions: Co-culture of iPSC-derived neurons and astrocytes enhanced the morphological changes mimicking the in vivo condition of both cell types. The formation of the functional tripartite synaptic structures in the co-culture model suggested the mutual interaction between the cells. Furthermore, the co-culture model with the APP V717L  mutation expressed in neurons exhibited an astrocytic phenotype reminiscent of AD brain pathology. These results suggest that our co-culture model is a valuable tool for disease modeling of neurodegenerative diseases., (© 2024. The Author(s).)

Background: A growing body of evidence suggests that immune dysfunction and inflammation in the peripheral tissues as well as the central nervous system are associated with the neurodevelopmental deficits observed in autism spectrum disorder (ASD). Elevated expression of pro-inflammatory cytokines in the plasma, serum, and peripheral blood mononuclear cells of ASD has been reported. These cytokine expression levels are associated with the severity of behavioral impairments and symptoms in ASD. In a prior study, our group reported that tumor necrosis factor-α (TNF-α) expression in granulocyte-macrophage colony-stimulating factor-induced macrophages (GM-CSF MΦ) and the TNF-α expression ratio in GM-CSF MΦ/M-CSF MΦ (macrophage colony-stimulating factor-induced macrophages) was markedly higher in individuals with ASD than in typically developed (TD) individuals. However, the mechanisms of how the macrophages and the highly expressed cytokines affect neurons remain to be addressed., Methods: To elucidate the effect of macrophages on human neurons, we used a co-culture system of control human-induced pluripotent stem cell-derived neurons and differentiated macrophages obtained from the peripheral blood mononuclear cells of five TD individuals and five individuals with ASD. All participants were male and ethnically Japanese., Results: Our results of co-culture experiments showed that GM-CSF MΦ affect the dendritic outgrowth of neurons through the secretion of pro-inflammatory cytokines, interleukin-1α and TNF-α. Macrophages derived from individuals with ASD exerted more severe effects than those derived from TD individuals., Limitations: The main limitations of our study were the small sample size with a gender bias toward males, the use of artificially polarized macrophages, and the inability to directly observe the interaction between neurons and macrophages from the same individuals., Conclusions: Our co-culture system revealed the non-cell autonomous adverse effects of GM-CSF MΦ in individuals with ASD on neurons, mediated by interleukin-1α and TNF-α. These results may support the immune dysfunction hypothesis of ASD, providing new insights into its pathology., (© 2024. The Author(s).)

Background: The HACOR score for predicting treatment failure includes vital signs and acid-base balance factors, whereas the ROX index only considers the respiratory rate, oxygen saturation, and fraction of inspired oxygen (FiO 2 ). We aimed to externally validate the HACOR score and ROX index for predicting treatment failure in patients with coronavirus disease 2019 (COVID-19) on high-flow nasal cannula (HFNC) therapy in Japan., Methods: This retrospective, observational, multicenter study included patients, aged ≥ 18 years, diagnosed with COVID-19 and treated with HFNC therapy between January 16, 2020, and March 31, 2022. The HACOR score and ROX index were calculated at 2, 6, 12, 24, and 48 h after stating HFNC therapy. The primary outcome was treatment failure (requirement for intubation or occurrence of death within 7 days). We calculated the area under the receiver operating characteristic curve (AUROC) and assessed the diagnostic performance of these indicators. The 2-h time-point prediction was considered the primary analysis and that of other time-points as the secondary analysis. We also assessed 2-h time-point sensitivity and specificity using previously reported cutoff values (HACOR score > 5, ROX index < 2.85)., Results: We analyzed 300 patients from 9 institutions (median age, 60 years; median SpO 2 /FiO 2 ratio at the start of HFNC therapy, 121). Within 7 days of HFNC therapy, treatment failure occurred in 127 (42%) patients. The HACOR score and ROX index at the 2-h time-point exhibited AUROC discrimination values of 0.63 and 0.57 (P = 0.24), respectively. These values varied with temporal changes-0.58 and 0.62 at 6 h, 0.70 and 0.68 at 12 h, 0.68 and 0.69 at 24 h, and 0.75 and 0.75 at 48 h, respectively. The 2-h time-point sensitivity and specificity were 18% and 91% for the HACOR score, respectively, and 3% and 100% for the ROX index, respectively. Visual calibration assessment revealed well calibrated HACOR score, but not ROX index., Conclusions: In COVID-19 patients receiving HFNC therapy in Japan, the predictive performance of the HACOR score and ROX index at the 2-h time-point may be inadequate. Furthermore, clinicians should be mindful of time-point scores owing to the variation of the models' predictive performance with the time-point. Trial registration UMIN (registration number: UMIN000050024, January 13, 2023)., (© 2024. The Author(s).)

Background: Severe peripheral nerve damage always requires surgical treatment. Autologous nerve transplantation is a standard treatment, but it is not sufficient due to length limitations and extended surgical time. Even with the available artificial nerves, there is still large room for improvement in their therapeutic effects. Novel treatments for peripheral nerve injury are greatly expected., Methods: Using a specialized microfluidic device, we generated artificial neurite bundles from human iPSC-derived motor and sensory nerve organoids. We developed a new technology to isolate cell-free neurite bundles from spheroids. Transplantation therapy was carried out for large nerve defects in rat sciatic nerve with novel artificial nerve conduit filled with lineally assembled sets of human neurite bundles. Quantitative comparisons were performed over time to search for the artificial nerve with the therapeutic effect, evaluating the recovery of motor and sensory functions and histological regeneration. In addition, a multidimensional unbiased gene expression profiling was carried out by using next-generation sequencing., Result: After transplantation, the neurite bundle-derived artificial nerves exerted significant therapeutic effects, both functionally and histologically. Remarkably, therapeutic efficacy was achieved without immunosuppression, even in xenotransplantation. Transplanted neurite bundles fully dissolved after several weeks, with no tumor formation or cell proliferation, confirming their biosafety. Posttransplant gene expression analysis highlighted the immune system's role in recovery., Conclusion: The combination of newly developed microfluidic devices and iPSC technology enables the preparation of artificial nerves from organoid-derived neurite bundles in advance for future treatment of peripheral nerve injury patients. A promising, safe, and effective peripheral nerve treatment is now ready for clinical application., (© 2024. The Author(s).)

Background: Human induced pluripotent stem cell-derived neural stem/progenitor cell (hiPSC-NS/PC)-based cell transplantation has emerged as a groundbreaking method for replacing damaged neural cells and stimulating functional recovery, but its efficacy is strongly influenced by the state of the injured spinal microenvironment. This study evaluates the impact of a dual therapeutic intervention utilizing hepatocyte growth factor (HGF) and hiPSC-NS/PC transplantation on motor function restoration following spinal cord injury (SCI)., Methods: Severe contusive SCI was induced in immunocompromised rats, followed by continuous administration of recombinant human HGF protein into the subarachnoid space immediately after SCI for two weeks. Acute-phase histological and RNA sequencing analyses were conducted. Nine days after the injury, hiPSC-NS/PCs were transplanted into the lesion epicenter of the injured spinal cord, and the functional and histological outcomes were determined., Results: The acute-phase HGF-treated group exhibited vascularization, diverse anti-inflammatory effects, and activation of endogenous neural stem cells after SCI, which collectively contributed to tissue preservation. Following cell transplantation into a favorable environment, the transplanted NS/PCs survived well, facilitating remyelination and neuronal regeneration in host tissues. These comprehensive effects led to substantial enhancements in motor function in the dual-therapy group compared to the single-treatment groups., Conclusions: We demonstrate that the combined therapeutic approach of HGF preconditioning and hiPSC-NS/PC transplantation enhances locomotor functional recovery post-SCI, highlighting a highly promising therapeutic strategy for acute to subacute SCI., (© 2023. Japanese Society of Inflammation and Regeneration.)

Background: Sugarcane trash (SCT) represents up to 18% of the aboveground biomass of sugarcane, surpassing 28 million tons globally per year. The majority of SCT is burning in the fields. Hence, efficient use of SCT is necessary to reduce carbon dioxide emissions and global warming and establish agro-industrial biorefineries. Apart from its low costs, conversion of whole biomass with high production efficiency and titer yield is mandatory for effective biorefinery systems. Therefore, in this study, we developed a simple, integrated method involving a single step of glycerolysis pretreatment to produce antiviral glycerolysis lignin (AGL). Subsequently, we co-fermented glycerol with hydrolyzed glucose and xylose to yield high titers of bioethanol., Results: SCT was subjected to pretreatment with microwave acidic glycerolysis with 50% aqueous (aq.) glycerol (MAG 50 ); this pretreatment was optimized across different temperature ranges, acid concentrations, and reaction times. The optimized MAG 50 ( op MAG 50 ) of SCT at 1:15 (w/v) in 1% H 2 SO 4, 360 µM AlK(SO 4 ) 2 at 140 °C for 30 min ( op MAG 50 ) recovered the highest amount of total sugars and the lowest amount of furfural byproducts. Following op MAG 50 , the soluble fraction, i.e., glycerol xylose-rich solution (GXRS), was separated by filtration. A residual pulp was then washed with acetone, recovering 7.9% of the dry weight (27% of lignin) as an AGL. AGL strongly inhibited the replication of encephalomyocarditis virus (EMCV) in L929 cells without cytotoxicity. The pulp was then saccharified in yeast peptone medium by cellulase to produce a glucose concentration similar to the theoretical yield. The total xylose and arabinose recoveries were 69% and 93%, respectively. GXRS and saccharified sugars were combined and co-fermented through mixed cultures of two metabolically engineered Saccharomyces cerevisiae strains: glycerol-fermenting yeast (SK-FGG4) and xylose-fermenting yeast (SK-N2). By co-fermenting glycerol and xylose with glucose, the ethanol titer yield increased to 78.7 g/L (10% v/v ethanol), with a 96% conversion efficiency., Conclusion: The integration of AGL production with the co-fermentation of glycerol, hydrolyzed glucose, and xylose to produce a high titer of bioethanol paves an avenue for the use of surplus glycerol from the biodiesel industry for the efficient utilization of SCT and other lignocellulosic biomasses., (© 2023. The Author(s).)

Cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL) is an inherited cerebral small vessel disease (CSVD) caused by biallelic mutations in the high-temperature requirement serine peptidase A1 (HTRA1) gene. Even heterozygous mutations in HTRA1 are recently revealed to cause cardinal clinical features of CSVD. Here, we report the first establishment of a human induced pluripotent stem cell (hiPSC) line from a patient with heterozygous HTRA1-related CSVD. Peripheral blood mononuclear cells (PBMCs) were reprogrammed by the transfection of episomal vectors encoding human OCT3/4 (POU5F1), SOX2, KLF4, L-MYC, LIN28, and a murine dominant-negative mutant of p53 (mp53DD). The established iPSCs had normal morphology as human pluripotent stem cells and normal karyotype (46XX). Moreover, we found that the HTRA1 missense mutation (c.905G>A, p.R302Q) was heterozygous. These iPSCs expressed pluripotency-related markers and had the potential to differentiate into all three germ layers in vitro. HTRA1 and the supposed disease-associated gene NOG were differentially expressed in the patient iPSCs at mRNA levels compared to those of control lines. The iPSC line would facilitate in vitro research for understanding the cellular pathomechanisms caused by the HTRA1 mutation including its dominant-negative effect., (© 2023. The Author(s).)

Background: Subarachnoid hemorrhage (SAH) is a fatal disease, with early brain injury (EBI) occurring within 72 h of SAH injury contributes to its poor prognosis. EBI is a complicated phenomenon involving multiple mechanisms. Although neuroinflammation has been shown to be important prognosis factor of EBI, whether neuroinflammation spreads throughout the cerebrum and the extent of its depth in the cerebral cortex remain unknown. Knowing how inflammation spreads throughout the cerebrum is also important to determine if anti-inflammatory agents are a future therapeutic strategy for EBI., Methods: In this study, we induced SAH in mice by injecting hematoma into prechiasmatic cistern and created models of mild to severe SAH. In sections of the mouse cerebrum, we investigated neuroinflammation and neuronal cell death in the cortex distal to the hematoma injection site, from anterior to posterior region 24 h after SAH injury., Results: Neuroinflammation caused by SAH spread to all layers of the cerebral cortex from the anterior to the posterior part of the cerebrum via the invasion of activated microglia, and neuronal cell death increased in correlation with neuroinflammation. This trend increased with the severity of the disease., Conclusions: Neuroinflammation caused by SAH had spread throughout the cerebrum, causing neuronal cell death. Considering that the cerebral cortex is responsible for long-term memory and movement, suppressing neuroinflammation in all layers of the cerebral cortex may improve the prognosis of patients with SAH., (© 2022. The Author(s).)

Background: Microglia are innate immune cells that are the only residential macrophages in the central nervous system. They play vital physiological roles in the adult brain and during development. Microglia are particularly in the spotlight because many genetic risk factors recently identified for neurodegenerative diseases are largely expressed in microglia. Rare polymorphisms in these risk alleles lead to abnormal activity of microglia under traumatic or disease conditions., Methods: In the present study, to investigate the multifaceted functions of human microglia, we established a novel robust protocol to generate microglia from human induced pluripotent stem cells (hiPSCs) using a combination of cytokines and small chemicals essential for microglia ontogeny. Moreover, we highly enhanced the microglial differentiation efficiency by forcing the expression of PU.1, a crucial transcription factor for microglial development, during posterior mesoderm differentiation., Results: By our novel method, we demonstrated the generation of a greater number of hiPSC-derived microglia (hiMGLs, approximately 120-folds) than the prior methods (at most 40-folds). Over 90% of the hiMGLs expressed microglia-specific markers, such as CX3CR1 and IBA-1. Whole-transcriptome analysis revealed that these hiMGLs are similar to human primary microglia but differ from monocytes/macrophages. Furthermore, the specific physiological functions of microglia were confirmed through indices of lipopolysaccharide responsiveness, phagocytotic ability, and inflammasome formation. By co-culturing these hiMGLs with mouse primary neurons, we demonstrated that hiMGLs can regulate the activity and maturation of neurons., Conclusions: In this study, our new simple, rapid, and highly efficient method for generating microglia from hiPSCs will prove useful for future investigations on microglia in both physiological and disease conditions, as well as for drug discovery., (© 2022. The Author(s).)

Background: Fine-tuned cochlear development is essential for hearing. Owing to the difficulty in using early human fetal samples, most of our knowledge regarding cochlear development has been obtained from rodents. However, several inter-species differences in cochlear development between rodents and humans have been reported. To bridge these differences, we investigated early otic development of a non-human primate model animal, the common marmoset (Callithrix jacchus)., Methods: We examined 20 genes involved in early cochlear development and described the critical developmental steps for morphogenesis, which have been reported to vary between rodents and marmosets., Results: The results revealed that several critical genes involved in prosensory epithelium specifications showed higher inter-species differences, suggesting that the molecular process for hair cell lineage acquisition in primates differs considerably from that of rodents. We also observed that the tempo of cochlear development was three times slower in the primate than in rodents., Conclusions: Our data provide new insights into early cochlear development in primates and humans and imply that the procedures used for manipulating rodent cochlear sensory cells cannot be directly used for the research of primate cells due to the intrinsic inter-species differences in the cell fate determination program., (© 2022. The Author(s).)

Since the worldwide outbreak of coronavirus disease 2019 (COVID-19) in 2020, various research reports and case reports have been published. It has been found that COVID-19 causes not only respiratory disorders but also thrombosis and gastrointestinal disorders, central nervous system (CNS) disorders, and peripheral neuropathy. Compared to other disorders, there are low number of research reports and low number of summaries on COVID-19-related neural disorders. Therefore, focusing on neural disorders, we outline both basic research and clinical manifestations of COVID-19-related neural disorders.

Background: Noninvasive respiratory support devices may reduce the tracheal intubation rate compared with conventional oxygen therapy (COT). To date, few studies have compared high-flow nasal cannula (HFNC) use with noninvasive positive-pressure ventilation (NPPV). We conducted a network meta-analysis to compare the effectiveness of three respiratory support devices in patients with acute respiratory failure., Methods: The Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, and Ichushi databases were searched. Studies including adults aged ≥ 16 years with acute hypoxic respiratory failure and randomized-controlled trials that compared two different oxygenation devices (COT, NPPV, or HFNC) before tracheal intubation were included. A frequentist-based approach with a multivariate random-effects meta-analysis was used. The network meta-analysis was performed using the GRADE Working Group approach. The outcomes were short-term mortality and intubation rate., Results: Among 5507 records, 27 studies (4618 patients) were included. The main cause of acute hypoxic respiratory failure was pneumonia. Compared with COT, NPPV and HFNC use tended to reduce mortality (relative risk, 0.88 and 0.93, respectively; 95% confidence intervals, 0.76-1.01 and 0.80-1.08, respectively; both low certainty) and lower the risk of endotracheal intubation (0.81 and 0.78; 0.72-0.91 and 0.68-0.89, respectively; both low certainty); however, short-term mortality or intubation rates did not differ (0.94 and 1.04, respectively; 0.78-1.15 and 0.88-1.22, respectively; both low certainty) between NPPV and HFNC use., Conclusion: NPPV and HFNC use are associated with a decreased risk of endotracheal intubation; however, there are no significant differences in short-term mortality., Trial Registration: PROSPERO (registration number: CRD42020139105 , 01/21/2020).

Mitochondrial structural changes are associated with the regulation of mitochondrial function, apoptosis, and neurodegenerative diseases. PRKN is known to be involved with various mechanisms of mitochondrial quality control including mitochondrial structural changes. Parkinson's disease (PD) with PRKN mutations is characterized by the preferential degeneration of dopaminergic neurons in the substantia nigra pars compacta, which has been suggested to result from the accumulation of damaged mitochondria. However, ultrastructural changes of mitochondria specifically in dopaminergic neurons derived from iPSC have rarely been analyzed. The main reason for this would be that the dopaminergic neurons cannot be distinguished directly among a mixture of iPSC-derived differentiated cells under electron microscopy. To selectively label dopaminergic neurons and analyze mitochondrial morphology at the ultrastructural level, we generated control and PRKN-mutated patient tyrosine hydroxylase reporter (TH-GFP) induced pluripotent stem cell (iPSC) lines. Correlative light-electron microscopy analysis and live cell imaging of GFP-expressing dopaminergic neurons indicated that iPSC-derived dopaminergic neurons had smaller and less functional mitochondria than those in non-dopaminergic neurons. Furthermore, the formation of spheroid-shaped mitochondria, which was induced in control dopaminergic neurons by a mitochondrial uncoupler, was inhibited in the PRKN-mutated dopaminergic neurons. These results indicate that our established TH-GFP iPSC lines are useful for characterizing mitochondrial morphology, such as spheroid-shaped mitochondria, in dopaminergic neurons among a mixture of various cell types. Our in vitro model would provide insights into the vulnerability of dopaminergic neurons and the processes leading to the preferential loss of dopaminergic neurons in patients with PRKN mutations.

CHD8 encodes a chromatin-remodeling factor and is one of the most recurrently mutated genes in individuals with autism spectrum disorder (ASD). Although we have recently shown that mice heterozygous for Chd8 mutation manifest myelination defects and ASD-like behaviors, the detailed mechanisms underlying ASD pathogenesis have remained unclear. Here we performed diffusion tensor imaging (DTI) and resting-state functional magnetic resonance imaging (rsfMRI) in oligodendrocyte lineage-specific Chd8 heterozygous mutant mice. DTI revealed that ablation of Chd8 specifically in oligodendrocytes of mice was associated with microstructural changes of specific brain regions including the cortex and striatum. The extent of these changes in white matter including the corpus callosum and fornix was correlated with total contact time in the reciprocal social interaction test. Analysis with rsfMRI revealed changes in functional brain connectivity in the mutant mice, and the extent of such changes in the cortex, hippocampus, and amygdala was also correlated with the change in social interaction. Our results thus suggest that changes in brain microstructure and functional connectivity induced by oligodendrocyte dysfunction might underlie altered social interaction in mice with oligodendrocyte-specific CHD8 haploinsufficiency.

Spinal cord injury (SCI) is a devastating event that causes permanent neurologic impairments. Cell transplantation therapy using neural precursor cells (NPCs) is a promising intervention aiming to replace damaged neural tissue and restore certain functions. Because the protocol to produce human induced pluripotent stem cells (iPSCs) was first established, we have attempted to apply this technology for regenerative therapy in SCI. Our group reported beneficial effects of iPSC-derived NPC transplantation and addressed safety issues on tumorigenicity after grafting. These findings will soon be tested at the clinical trial stage, the protocol of which has already been approved by the Ministry of Health, Labour and Welfare in Japan. Current transplantation therapies treat patients at the subacute phase after injury, highlighting the need for effective treatments for chronic SCI. We recently demonstrated the modest efficacy of gamma secretase inhibitor treatment of iPSC-NPCs before transplantation at the chronic phase. However, more comprehensive strategies involving combinatory therapies are essential to enhance current spinal cord regeneration treatments., Competing Interests: Competing interestsThe authors declare that they have no competing interests., (© The Author(s) 2020.)

It has been reported that coronavirus disease 2019 (COVID-19) causes not only pneumonia but also systemic inflammations including central nervous system (CNS) disorders. However, little is known about the mechanism that triggers the COVID-19-associated CNS disorders, due to the lack of appropriate experimental systems. Our present study showed that angiotensin-converting enzyme-2 (ACE2), a cellular receptor for SARS-CoV-2, is expressed in human induced pluripotent stem cell (iPSC)-derived neural stem/progenitor cells (hiPSC-NS/PCs) and young neurons. Furthermore, together with database analysis, we found that a viral virulent factor CCN family member 1 (CCN1), which is known to be induced by SARS-CoV-2 infection, is expressed in these cells at basal levels. Considering the role of CCN1 which is known to be involved in viral toxicity and inflammation, hiPSC-NS/PCs could provide an excellent model for COVID-19-associated CNS disorders from the aspect of SARS-CoV-2 infection-ACE2-CCN1 axis. In addition, we identified compounds that reduce CCN1 expression. Collectively, our study using hiPSC-NS/PCs may aid in the development of a therapeutic target for COVID-19-related CNS disorders., Competing Interests: Competing interestsH.O. is a scientific advisor of K Pharma Inc. and Regenerative Medicine iPS Gateway Center Co., Ltd., (© The Author(s) 2020.)

The transplantation of neural progenitor cells (NPCs) derived from human induced pluripotent stem cells (iPSCs) has beneficial effects on spinal cord injury (SCI). However, while there are many subtypes of NPCs with different regional identities, the subtype of iPSC-derived NPCs that is most appropriate for cell therapy for SCI has not been identified. Here, we generated forebrain- and spinal cord-type NPCs from human iPSCs and grafted them onto the injured spinal cord in mice. These two types of NPCs retained their regional identities after transplantation and exhibited different graft-host interconnection properties. NPCs with spinal cord regional identity but not those with forebrain identity resulted in functional improvement in SCI mice, especially in those with mild-to-moderate lesions. This study highlights the importance of the regional identity of human iPSC-derived NPCs used in cell therapy for SCI.

Background: Several genetic alterations, including point mutations and copy number variations in NLGN genes, have been associated with psychiatric disorders, such as autism spectrum disorder (ASD) and X-linked mental retardation (XLMR). NLGN genes encode neuroligin (NL) proteins, which are adhesion molecules that are important for proper synaptic formation and maturation. Previously, we and others found that the expression level of murine NL1 is regulated by proteolytic processing in a synaptic activity-dependent manner., Methods: In this study, we analyzed the effects of missense variants associated with ASD and XLMR on the metabolism and function of NL4X, a protein which is encoded by the NLGN4X gene and is expressed only in humans, using cultured cells, primary neurons from rodents, and human induced pluripotent stem cell-derived neurons., Results: NL4X was found to undergo proteolytic processing in human neuronal cells. Almost all NL4X variants caused a substantial decrease in the levels of mature NL4X and its synaptogenic activity in a heterologous culture system. Intriguingly, the L593F variant of NL4X accelerated the proteolysis of mature NL4X proteins located on the cell surface. In contrast, other variants decreased the cell-surface trafficking of NL4X. Notably, protease inhibitors as well as chemical chaperones rescued the expression of mature NL4X., Limitations: Our study did not reveal whether these dysfunctional phenotypes occurred in individuals carrying NLGN4X variant. Moreover, though these pathological mechanisms could be exploited as potential drug targets for ASD, it remains unclear whether these compounds would have beneficial effects on ASD model animals and patients., Conclusions: These data suggest that reduced amounts of the functional NL4X protein on the cell surface is a common mechanism by which point mutants of the NL4X protein cause psychiatric disorders, although different molecular mechanisms are thought to be involved. Furthermore, these results highlight that the precision medicine approach based on genetic and cell biological analyses is important for the development of therapeutics for psychiatric disorders.

Adult neurogenesis occurs throughout life in restricted brain regions in mammals. However, the number of neural stem cells (NSCs) that generate new neurons steadily decreases with age, resulting in a decrease in neurogenesis. Transplantation of mesenchymal cells or cultured NSCs has been studied as a promising treatment in models of several brain injuries including cerebral infarction and cerebral contusion. Considering the problems of host-versus-graft reactions and the tumorigenicity of transplanted cells, the mobilization of endogenous adult NSCs should be more feasible for the treatment of these brain injuries. However, the number of adult NSCs in the adult brain is limited, and their mitotic potential is low. Here, we outline what we know to date about why the number of NSCs and adult neurogenesis decrease with age. We also discuss issues applicable to regenerative medicine., Competing Interests: Competing interestsThe authors declare that they have no competing interests., (© The Author(s) 2020.)

Background: The common marmoset (Callithrix jacchus) is one of the most studied primate model organisms. However, the marmoset genomes available in the public databases are highly fragmented and filled with sequence gaps, hindering research advances related to marmoset genomics and transcriptomics., Results: Here we utilize single-molecule, long-read sequence data to improve and update the existing genome assembly and report a near-complete genome of the common marmoset. The assembly is of 2.79 Gb size, with a contig N50 length of 6.37 Mb and a chromosomal scaffold N50 length of 143.91 Mb, representing the most contiguous and high-quality marmoset genome up to date. Approximately 90% of the assembled genome was represented in contigs longer than 1 Mb, with approximately 104-fold improvement in contiguity over the previously published marmoset genome. More than 98% of the gaps from the previously published genomes were filled successfully, which improved the mapping rates of genomic and transcriptomic data on to the assembled genome., Conclusions: Altogether the updated, high-quality common marmoset genome assembly provide improvements at various levels over the previous versions of the marmoset genome assemblies. This will allow researchers working on primate genomics to apply the genome more efficiently for their genomic and transcriptomic sequence data.

Spinal bulbar muscular atrophy (SBMA) is an adult-onset, slowly progressive motor neuron disease caused by abnormal CAG repeat expansion in the androgen receptor (AR) gene. Although ligand (testosterone)-dependent mutant AR aggregation has been shown to play important roles in motor neuronal degeneration by the analyses of transgenic mice models and in vitro cell culture models, the underlying disease mechanisms remain to be fully elucidated because of the discrepancy between model mice and SBMA patients. Thus, novel human disease models that recapitulate SBMA patients' pathology more accurately are required for more precise pathophysiological analysis and the development of novel therapeutics. Here, we established disease specific iPSCs from four SBMA patients, and differentiated them into spinal motor neurons. To investigate motor neuron specific pathology, we purified iPSC-derived motor neurons using flow cytometry and cell sorting based on the motor neuron specific reporter, HB9 e438 ::Venus, and proceeded to the genome-wide transcriptome analysis by RNA sequences. The results revealed the involvement of the pathology associated with synapses, epigenetics, and endoplasmic reticulum (ER) in SBMA. Notably, we demonstrated the involvement of the neuromuscular synapse via significant upregulation of Synaptotagmin, R-Spondin2 (RSPO2), and WNT ligands in motor neurons derived from SBMA patients, which are known to be associated with neuromuscular junction (NMJ) formation and acetylcholine receptor (AChR) clustering. These aberrant gene expression in neuromuscular synapses might represent a novel therapeutic target for SBMA.

Glioblastoma exhibits phenotypic and genetic heterogeneity, aggressive invasiveness, therapeutic resistance, and tumor recurrence, which can be explained by the existence of glioma stem cells (GSCs). In this study, we visualized the spatiotemporal dynamics of invasion of human GSCs in an orthotopic xenograft mouse model using time-lapse imaging of organotypic brain slice cultures and three-dimensional imaging of optically cleared whole brains. GSCs implanted in the striatum exhibited directional migration toward axon bundles, perivascular area, and the subventricular zone around the inferior horn of the lateral ventricle. GSCs migrated in a helical pattern around axon bundles in the striatum and invaded broadly in both the rostral and caudal directions. GSCs in the corpus callosum migrated more rapidly and unidirectionally toward the contralateral side with pseudopod extension. These characteristics of GSC invasion shared histological features observed in glioblastoma patients. Spatiotemporal visualization techniques can contribute to the elucidation of the mechanisms underlying GSC invasion that may lead to the development of effective therapy for glioblastoma.

Parkinson's disease (PD) is associated with both motor and non-motor symptoms, including constipation, sensory neuropathy, depression, dementia and sleep disorder. Somatostatin (SST) is considered to be a modulator of GABAergic inhibitory transmission, and its levels are reduced in cerebrospinal fluid of PD patients. In the present study, we evaluated the changes in the expression of SST in GABAergic neurons derived from induced pluripotent stem cells (iPSCs) of PD patients. Neural cells were co-treated with the Wnt antagonist IWP-2 and Shh during neurosphere formation to induce GABA-positive forebrain interneurons. Quantitative analyses showed no significant differences, but slight decreases, in the potency of differentiation into GABAergic neurons derived from iPSCs between healthy control and patients with PARK2 mutations, who have been classified as a type of early-onset familial PD due to mutations in the parkin gene. Under this condition, the mRNA level of SST in GABAergic interneurons derived from iPSCs of PARK2-specific PD patients significantly decreased as neural maturation progressed. We also found that SST-positive GABAergic neurons were clearly reduced in GABAergic neurons derived from iPSCs of patients with PARK2 mutations. These findings suggest that the reduction in the expression level of SST in GABAergic interneurons of PD may, at least partly, lead to complex PD-induced symptoms.

Background: Contact domains of chromatin serve as a fundamental unit to regulate action of enhancers for target genes. Looping between a pair of CCCTC-binding factor (CTCF)-binding sites in convergent orientations underlies the formation of contact domains, while those in divergent orientations establish domain boundaries. However, every CTCF site is not necessarily engaged in loop or boundary structures, leaving functions of CTCF in varied genomic contexts still elusive. The locus containing Tfap2c and Bmp7 encompasses two contact domains separated by a region between the two genes, termed transition zone (TZ), characterized by two arrays of CTCF sites in divergent configuration. In this study, we created deletion and inversion alleles of these and other regions across the locus and investigated how they impinge on the conformation., Results: Deletion of the whole two CTCF arrays with the CRISPR/Cas9 system resulted in impairment of blocking of chromatin contacts by the TZ, as assessed by the circular chromatin conformation capture assay (4C-seq). Deletion and inversion of either of the two arrays similarly, but less pronouncedly, led to reduction in the blocking activity. Thus, the divergent configuration provides the TZ with the strong boundary activity. Uniquely, we show the TZ harbors a 50-kb region within one of the two arrays that contacts broadly with the both flanking intervals, regardless of the presence or orientation of the other CTCF array. Further, we show the boundary CTCF array has little impact on intra-domain folding; instead, locally associating CTCF sites greatly affect it., Conclusions: Our results show that the TZ not only separates the two domains, but also bears a wide interval that shows isotropic behavior of chromatin folding, indicating a potentially complex nature of actual boundaries in the genome. We also show that CTCF-binding sites inside a domain greatly contribute to the intra-domain folding of chromatin. Thus, the study reveals diverse and context-dependent roles of CTCF in organizing chromatin conformation at different levels.

Ghrelin exerts a wide range of physiological actions throughout the body and appears to be a promising target for disease therapy. Endogenous ghrelin receptors (GHSRs) are present in extrahypothalamic sites including the substantia nigra pars compacta (SNc), which is related to phenotypic dysregulation or frank degeneration in Parkinson's disease (PD). Here we found a dramatic decrease in the expression of GHSR in PD-specific induced pluripotent stem cell (iPSC)-derived dopaminergic (DAnergic) neurons generated from patients carrying parkin gene (PARK2) mutations compared to those from healthy controls. Consistently, a significant decrease in the expression of GHSR was found in DAnergic neurons of isogenic PARK2-iPSC lines that mimicked loss of function of the PARK2 gene through CRISPR Cas9 technology. Furthermore, either intracerebroventricular injection or microinjection into the SNc of the selective GHSR1a antagonist [D-Lys3]-GHRP6 in normal mice produced cataleptic behaviors related to dysfunction of motor coordination. These findings suggest that the down-regulation of GHSRs in SNc-DA neurons induced the initial dysfunction of DA neurons, leading to extrapyramidal disorder under PD.

Background: Surgical cricothyroidotomy is considered to be the last resort for management of the difficult airway. A major point for a successful surgical cricothyroidotomy is to identify the location of the cricothyroid membrane., Case Presentation: We encountered a patient with progressive respiratory distress who was anticipated to have a difficult airway due to a large neck abscess. We prepared for both awake intubation and surgical cricothyroidotomy. The cricothyroid membrane could not be identified by palpation, but was readily identified using ultrasound., Conclusion: Ultrasound-guided identification of the cricothyroid membrane may be useful in a patient with a difficult airway due to neck swelling.

Dental pulp stem cells/progenitor cells (DPSCs) can be easily obtained and can have excellent proliferative and mineralization potentials. Therefore, many studies have investigated the isolation and bone formation of DPSCs. In most previous reports, human DPSCs were traditionally isolated by exploiting their ability to adhere to plastic tissue culture dishes. DPSCs isolated by plastic adherence are frequently contaminated by other cells, which limits the ability to investigate their basic biology and regenerative properties. Additionally, the proliferative and osteogenic potentials vary depending on the isolated cells. It is very difficult to obtain cells of a sufficient quality to elicit the required effect upon transplantation. Considering clinical applications, stem cells used for regenerative medicine need to be purified in order to increase the efficiency of bone regeneration, and a stable supply of these cells must be generated. Here, we review the purification of DPSCs and studies of cranio-maxillofacial bone regeneration using these cells. Additionally, we introduce the prospective isolation of DPSCs using specific cell surface markers: low-affinity nerve growth factor and thymocyte antigen 1.

Macrophage migration inhibitory factor (MIF) plays an important role in supporting the proliferation and/or survival of murine neural stem/progenitor cells (NSPCs); however, the downstream effectors of this factor remain unknown. Here, we show that MIF increases the expression of Pax6 and Chd7 in NSPCs in vitro. During neural development, the chromatin remodeling factor Chd7 (chromatin helicase-DNA-binding protein 7) is expressed in the ventricular zone of the telencephalon of mouse brain at embryonic day 14.5, as well as in cultured NSPCs. Retroviral overexpression of Pax6 in NSPCs increased Chd7 gene expression. Lentivirally-expressed Chd7 shRNA suppressed cell proliferation and neurosphere formation, and inhibited neurogenesis in vitro, while decreasing gene expression of Hes5 and N-myc. In addition, CHD7 overexpression increased cell proliferation in human embryonic stem cell-derived NSPCs (ES-NSPCs). In Chd7 mutant fetal mouse brains, there were fewer intermediate progenitor cells (IPCs) compared to wildtype littermates, indicating that Chd7 contributes to neurogenesis in the early developmental mouse brain. Furthermore, in silico database analysis showed that, among members of the CHD family, CHD7 is highly expressed in human gliomas. Interestingly, high levels of CHD7 gene expression in human glioma initiating cells (GICs) compared to normal astrocytes were revealed and gene silencing of CHD7 decreased GIC proliferation. Collectively, our data demonstrate that CHD7 is an important factor in the proliferation and stemness maintenance of NSPCs, and CHD7 is a promising therapeutic target for the treatment of gliomas.

Patient-specific induced pluripotent stem cells (iPSCs) facilitate understanding of the etiology of diseases, discovery of new drugs and development of novel therapeutic interventions. A frequently used starting source of cells for generating iPSCs has been dermal fibroblasts (DFs) isolated from skin biopsies. However, there are also numerous repositories containing lymphoblastoid B-cell lines (LCLs) generated from a variety of patients. To date, this rich bioresource of LCLs has been underused for generating iPSCs, and its use would greatly expand the range of targeted diseases that could be studied by using patient-specific iPSCs. However, it remains unclear whether patient's LCL-derived iPSCs (LiPSCs) can function as a disease model. Therefore, we generated Parkinson's disease patient-specific LiPSCs and evaluated their utility as tools for modeling neurological diseases. We established iPSCs from two LCL clones, which were derived from a healthy donor and a patient carrying PARK2 mutations, by using existing non-integrating episomal protocols. Whole genome sequencing (WGS) and comparative genomic hybridization (CGH) analyses showed that the appearance of somatic variations in the genomes of the iPSCs did not vary substantially according to the original cell types (LCLs, T-cells and fibroblasts). Furthermore, LiPSCs could be differentiated into functional neurons by using the direct neurosphere conversion method (dNS method), and they showed several Parkinson's disease phenotypes that were similar to those of DF-iPSCs. These data indicate that the global LCL repositories can be used as a resource for generating iPSCs and disease models. Thus, LCLs are the powerful tools for generating iPSCs and modeling neurological diseases.

The risk of tumorigenicity is a hurdle for regenerative medicine using induced pluripotent stem cells (iPSCs). Although teratoma formation is readily distinguishable, the malignant transformation of iPSC derivatives has not been clearly defined due to insufficient analysis of histology and phenotype. In the present study, we evaluated the histology of neural stem/progenitor cells (NSPCs) generated from integration-free human peripheral blood mononuclear cell (PBMC)-derived iPSCs (iPSC-NSPCs) following transplantation into central nervous system (CNS) of immunodeficient mice. We found that transplanted iPSC-NSPCs produced differentiation patterns resembling those in embryonic CNS development, and that the microenvironment of the final site of migration affected their maturational stage. Genomic instability of iPSCs correlated with increased proliferation of transplants, although no carcinogenesis was evident. The histological classifications presented here may provide cues for addressing potential safety issues confronting regenerative medicine involving iPSCs.

Background: The cancer stem cells (CSCs), a small subpopulation of cells in tumor are responsible for the tumor initiation, growth, recurrence and metastasis of cancer, as well as resistance of cancers to drugs or radiotherapy. CSCs are an important target for the development of novel strategies in cancer treatment. However, CSCs-targeted new anti-cancer drug discovery is currently hindered by the lack of easy and reliable methods for isolating, collecting and maintaining sufficient number of CSCs. Here, we examined whether introduction of defined reprogramming factors (Oct4, shp53, Sox2, Klf4, l-Myc and Lin28) into HSC2 tongue cancer cells could transform the HSC2 into HSC2 with CSCs properties., Methods: We introduced the defined reprogramming factors into HSC2 tongue cancer cells via episomal vectors by electroporation method to generate transfectant cells. We investigated the malignant properties of the transfectant cells by cell proliferation assay, migration assay, wound healing assay, sphere formation assay, chemosensitivity and radiosensitivity assay in vitro; and also examined the tumorigenic potential of the transfectants in vivo., Results: The transfectant cells (HSC2/hOCT3/4-shp53-F, HSC2/hSK, HSC2/hUL, HSC2/hOCT3/4-shp53-F + hSK, HSC2/hOCT3/4-shp53-F + hUL, HSC2/hSK + hUL, HSC2/hOCT3/4-shp53-F + hSK + hUL) displayed a malignant phenotype in culture and form tumors on the back of nude mice more efficiently than parental HSC2 and control HSC2/EGFP transfectant cells. They exhibited increased resistance to chemotherapeutic agents; 5-fluorouracil, cisplatin, docetaxel, trifluorothymidine, zoledronic acid, cetuximab, bortezomib and radiation when compared with HSC2 and HSC2/EGFP. Among all the transfected cells, HSC2/hOCT3/4-shp53-F + hSK + hUL cell containing all of the reprogramming factors showed the most aggressive and malignant properties and presented the highest number of spheres in the culture medium containing human recombinant fibroblast Growth Factor-2 (FGF-2) and epidermal Growth Factor (EGF)., Conclusion: These findings suggest that artificial cancer stem cells obtained by the induction of cellular reprogramming may be useful for investigating the acquisition of potential malignancy as well as screening the CSCs-targeting drugs.

Background: Lissencephaly, or smooth brain, is a severe congenital brain malformation that is thought to be associated with impaired neuronal migration during corticogenesis. However, the exact etiology of lissencephaly in humans remains unknown. Research on congenital diseases is limited by the shortage of clinically derived resources, especially for rare pediatric diseases. The research on lissencephaly is further limited because gyration in humans is more evolved than that in model animals such as mice. To overcome these limitations, we generated induced pluripotent stem cells (iPSCs) from the umbilical cord and peripheral blood of two lissencephaly patients with different clinical severities carrying alpha tubulin (TUBA1A) missense mutations (Patient A, p.N329S; Patient B, p.R264C)., Results: Neural progenitor cells were generated from these iPSCs (iPSC-NPCs) using SMAD signaling inhibitors. These iPSC-NPCs expressed TUBA1A at much higher levels than undifferentiated iPSCs and, like fetal NPCs, readily differentiated into neurons. Using these lissencephaly iPSC-NPCs, we showed that the neurons derived from the iPSCs obtained from Patient A but not those obtained from Patient B showed abnormal neurite extension, which correlated with the pathological severity in the brains of the patients., Conclusion: We established iPSCs derived from lissencephaly patients and successfully modeled one aspect of the pathogenesis of lissencephaly in vitro using iPSC-NPCs and iPSC-derived neurons. The iPSCs from patients with brain malformation diseases helped us understand the mechanism underlying rare diseases and human corticogenesis without the use of postmortem brains.

Background: Human pluripotent stem cells (hPSCs) are being applied in regenerative medicine and for the in vitro modeling of human intractable disorders. In particular, neural cells derived from disease-specific human induced pluripotent stem cells (hiPSCs) established from patients with neurological disorders have been used as in vitro disease models to recapitulate in vivo pathogenesis because neural cells cannot be usually obtained from patients themselves., Results: In this study, we established a rapid, efficient, and simple method for efficiently deriving motor neurons from hPSCs that is useful for pathophysiological analysis and the development of drugs to treat motor neuron diseases. Treatment with GSK3β inhibitors during the initial phase of differentiation in combination with dual SMAD inhibition was sufficient to induce PAX6 (+) and SOX1 (+) neural progenitors within 1 week, and subsequent treatment with retinoic acid (RA) and purmorphamine, which activates sonic hedgehog (SHH) signaling, resulted in the highly efficient induction of HB9(+) and ISL-1(+) motor neurons within 2 weeks. After 4 weeks of monolayer differentiation in motor neuron maturation medium, hPSC-derived motor neurons were shown to mature, displaying larger somas and clearer staining for the mature motor neuron marker choline acetyltransferase (ChAT). Moreover, hPSC-derived motor neurons were able to form neuromuscular junctions with human myotubes in vitro and induced acetylcholine receptor (AChR) clustering, as detected by Alexa 555-conjugated α-Bungarotoxin (α-BTX), suggesting that these hPSC-derived motor neurons formed functional contacts with skeletal muscles. This differentiation system is simple and is reproducible in several hiPSC clones, thereby minimizing clonal variation among hPSC clones. We also established a system for visualizing motor neurons with a lentiviral reporter for HB9 (HB9 (e438) ::Venus). The specificity of this reporter was confirmed through immunocytochemistry and quantitative RT-PCR analysis of high-positive fractions obtained via fluorescence-activated cell sorting (FACS), suggesting its applicability for motor neuron-specific analysis., Conclusions: Our motor neuron differentiation system and lentivirus-based reporter system for motor neurons facilitate the analysis of disease-specific hiPSCs for motor neuron diseases.

Background: Rett syndrome (RTT) is one of the most prevalent neurodevelopmental disorders in females, caused by de novo mutations in the X-linked methyl CpG-binding protein 2 gene, MECP2. Although abnormal regulation of neuronal genes due to mutant MeCP2 is thought to induce autistic behavior and impaired development in RTT patients, precise cellular mechanisms underlying the aberrant neural progression remain unclear., Results: Two sets of isogenic pairs of either wild-type or mutant MECP2-expressing human induced pluripotent stem cell (hiPSC) lines were generated from a single pair of 10-year-old RTT-monozygotic (MZ) female twins. Mutant MeCP2-expressing hiPSC lines did not express detectable MeCP2 protein during any stage of differentiation. The lack of MeCP2 reflected altered gene expression patterns in differentiated neural cells rather than in undifferentiated hiPSCs, as assessed by microarray analysis. Furthermore, MeCP2 deficiency in the neural cell lineage increased astrocyte-specific differentiation from multipotent neural stem cells. Additionally, chromatin immunoprecipitation (ChIP) and bisulfite sequencing assays indicated that anomalous glial fibrillary acidic protein gene (GFAP) expression in the MeCP2-negative, differentiated neural cells resulted from the absence of MeCP2 binding to the GFAP gene., Conclusions: An isogenic RTT-hiPSC model demonstrated that MeCP2 participates in the differentiation of neural cells. Moreover, MeCP2 deficiency triggers perturbation of astrocytic gene expression, yielding accelerated astrocyte formation from RTT-hiPSC-derived neural stem cells. These findings are likely to shed new light on astrocytic abnormalities in RTT, and suggest that astrocytes, which are required for neuronal homeostasis and function, might be a new target of RTT therapy.

Background: Retinitis pigmentosa (RP) is an inherited human retinal disorder that causes progressive photoreceptor cell loss, leading to severe vision impairment or blindness. However, no effective therapy has been established to date. Although genetic mutations have been identified, the available clinical data are not always sufficient to elucidate the roles of these mutations in disease pathogenesis, a situation that is partially due to differences in genetic backgrounds., Results: We generated induced pluripotent stem cells (iPSCs) from an RP patient carrying a rhodopsin mutation (E181K). Using helper-dependent adenoviral vector (HDAdV) gene transfer, the mutation was corrected in the patient's iPSCs and also introduced into control iPSCs. The cells were then subjected to retinal differentiation; the resulting rod photoreceptor cells were labeled with an Nrl promoter-driven enhanced green fluorescent protein (EGFP)-carrying adenovirus and purified using flow cytometry after 5 weeks of culture. Using this approach, we found a reduced survival rate in the photoreceptor cells with the E181K mutation, which was correlated with the increased expression of endoplasmic reticulum (ER) stress and apoptotic markers. The screening of therapeutic reagents showed that rapamycin, PP242, AICAR, NQDI-1, and salubrinal promoted the survival of the patient's iPSC-derived photoreceptor cells, with a concomitant reduction in markers of ER stress and apoptosis. Additionally, autophagy markers were found to be correlated with ER stress, suggesting that autophagy was reduced by suppressing ER stress-induced apoptotic changes., Conclusion: The use of RP patient-derived iPSCs combined with genome editing provided a versatile cellular system with which to define the roles of genetic mutations in isogenic iPSCs with or without mutation and also provided a system that can be used to explore candidate therapeutic approaches.

Background: The common marmoset (Callithrix jacchus) is a New World primate sharing many similarities with humans. Recently developed technology for generating transgenic marmosets has opened new avenues for faithful recapitulation of human diseases, which could not be achieved in rodent models. However, the longer lifespan of common marmosets compared with rodents may result in an extended period for in vivo analysis of common marmoset disease models. Therefore, establishing rapid and efficient techniques for obtaining neuronal cells from transgenic individuals that enable in vitro analysis of molecular mechanisms underlying diseases are required. Recently, several groups have reported on methods, termed direct reprogramming, to generate neuronal cells by defined factors from somatic cells of various kinds of species, including mouse and human. The aim of the present study was to determine whether direct reprogramming technology was applicable to common marmosets., Results: Common marmoset induced neuronal (cjiN) cells with neuronal morphology were generated from common marmoset embryonic skin fibroblasts (cjF) by overexpressing the neuronal transcription factors: ASCL1, BRN2, MYT1L and NEUROD1. Reverse transcription-polymerase chain reaction of cjiN cells showed upregulation of neuronal genes highly related to neuronal differentiation and function. The presence of neuronal marker proteins was also confirmed by immunocytochemistry. Electrical field stimulation to cjiN cells increased the intracellular calcium level, which was reversibly blocked by the voltage-gated sodium channel blocker, tetrodotoxin, indicating that these cells were functional. The neuronal function of these cells was further confirmed by electrophysiological analyses showing that action potentials could be elicited by membrane depolarization in current-clamp mode while both fast-activating and inactivating sodium currents and outward currents were observed in voltage-clamp mode. The 5-bromodeoxyuridine (BrdU) incorporation assay showed that cjiN cells were directly converted from cjFs without passing a proliferative state., Conclusions: Functional common marmoset neuronal cells can be obtained directly from embryonic fibroblasts by overexpressing four neuronal transcription factors under in vitro conditions. Overall, direct conversion technology on marmoset somatic cells provides the opportunity to analyze and screen phenotypes of genetically-modified common marmosets.

In 2006, we demonstrated that mature somatic cells can be reprogrammed to a pluripotent state by gene transfer, generating induced pluripotent stem (iPS) cells. Since that time, there has been an enormous increase in interest regarding the application of iPS cell technologies to medical science, in particular for regenerative medicine and human disease modeling. In this review article, we outline the current status of applications of iPS technology to cell therapies (particularly for spinal cord injury), as well as neurological disease-specific iPS cell research (particularly for Parkinson's disease and Alzheimer's disease). Finally, future directions of iPS cell research are discussed including a) development of an accurate assay system for disease-associated phenotypes, b) demonstration of causative relationships between genotypes and phenotypes by genome editing, c) application to sporadic and common diseases, and d) application to preemptive medicine.

Background: Rats exhibit extremely limited motor function recovery after total transection of the spinal cord (SCT). We previously reported that SM-216289, a semaphorin3A inhibitor, enhanced axon regeneration and motor function recovery in SCT adult rats. However, these effects were limited because most regenerated axons likely do not connect to the right targets. Thus, rebuilding the appropriate connections for regenerated axons may enhance recovery. In this study, we combined semaphorin3A inhibitor treatment with extensive treadmill training to determine whether combined treatment would further enhance the "rewiring" of regenerated axons. In this study, which aimed for clinical applicability, we administered a newly developed, potent semaphorin3A inhibitor, SM-345431 (Vinaxanthone), using a novel drug delivery system that enables continuous drug delivery over the period of the experiment., Results: Treatment with SM-345431 using this delivery system enhanced axon regeneration and produced significant, but limited, hindlimb motor function recovery. Although extensive treadmill training combined with SM-345431 administration did not further improve axon regeneration, hindlimb motor performance was restored, as evidenced by the significant improvement in the execution of plantar steps on a treadmill. In contrast, control SCT rats could not execute plantar steps at any point during the experimental period. Further analyses suggested that this strategy reinforced the wiring of central pattern generators in lumbar spinal circuits, which, in turn, led to enhanced motor function recovery (especially in extensor muscles)., Conclusions: This study highlights the importance of combining treatments that promote axon regeneration with specific and appropriate rehabilitations that promote rewiring for the treatment of spinal cord injury.

Background: Cervical compressive myelopathy (CCM) is caused by chronic spinal cord compression due to spondylosis, a degenerative disc disease, and ossification of the ligaments. Tip-toe walking Yoshimura (twy) mice are reported to be an ideal animal model for CCM-related neuronal dysfunction, because they develop spontaneous spinal cord compression without any artificial manipulation. Previous histological studies showed that neurons are lost due to apoptosis in CCM, but the mechanism underlying this neurodegeneration was not fully elucidated. The purpose of this study was to investigate the pathophysiology of CCM by evaluating the global gene expression of the compressed spinal cord and comparing the transcriptome analysis with the physical and histological findings in twy mice., Methods: Twenty-week-old twy mice were divided into two groups according to the magnetic resonance imaging (MRI) findings: a severe compression (S) group and a mild compression (M) group. The transcriptome was analyzed by microarray and RT-PCR. The cellular pathophysiology was examined by immunohistological analysis and immuno-electron microscopy. Motor function was assessed by Rotarod treadmill latency and stride-length tests., Results: Severe cervical calcification caused spinal canal stenosis and low functional capacity in twy mice. The microarray analysis revealed 215 genes that showed significantly different expression levels between the S and the M groups. Pathway analysis revealed that genes expressed at higher levels in the S group were enriched for terms related to the regulation of inflammation in the compressed spinal cord. M1 macrophage-dominant inflammation was present in the S group, and cysteine-rich protein 61 (Cyr61), an inducer of M1 macrophages, was markedly upregulated in these spinal cords. Furthermore, C1q, which initiates the classical complement cascade, was more upregulated in the S group than in the M group. The confocal and electron microscopy observations indicated that classically activated microglia/macrophages had migrated to the compressed spinal cord and eliminated synaptic terminals., Conclusions: We revealed the detailed pathophysiology of the inflammatory response in an animal model of chronic spinal cord compression. Our findings suggest that complement-mediated synapse elimination is a central mechanism underlying the neurodegeneration in CCM.

Background: A long non-coding RNA (lncRNA), nuclear-enriched abundant transcript 1&#95;2 (NEAT1&#95;2), constitutes nuclear bodies known as "paraspeckles". Mutations of RNA binding proteins, including TAR DNA-binding protein-43 (TDP-43) and fused in sarcoma/translocated in liposarcoma (FUS/TLS), have been described in amyotrophic lateral sclerosis (ALS). ALS is a devastating motor neuron disease, which progresses rapidly to a total loss of upper and lower motor neurons, with consciousness sustained. The aim of this study was to clarify the interaction of paraspeckles with ALS-associated RNA-binding proteins, and to identify increased occurrence of paraspeckles in the nucleus of ALS spinal motor neurons., Results: In situ hybridization (ISH) and ultraviolet cross-linking and immunoprecipitation were carried out to investigate interactions of NEAT1&#95;2 lncRNA with ALS-associated RNA-binding proteins, and to test if paraspeckles form in ALS spinal motor neurons. As the results, TDP-43 and FUS/TLS were enriched in paraspeckles and bound to NEAT1&#95;2 lncRNA directly. The paraspeckles were localized apart from the Cajal bodies, which were also known to be related to RNA metabolism. Analyses of 633 human spinal motor neurons in six ALS cases showed NEAT1&#95;2 lncRNA was upregulated during the early stage of ALS pathogenesis. In addition, localization of NEAT1&#95;2 lncRNA was identified in detail by electron microscopic analysis combined with ISH for NEAT1&#95;2 lncRNA. The observation indicating specific assembly of NEAT1&#95;2 lncRNA around the interchromatin granule-associated zone in the nucleus of ALS spinal motor neurons verified characteristic paraspeckle formation., Conclusions: NEAT1&#95;2 lncRNA may act as a scaffold of RNAs and RNA binding proteins in the nuclei of ALS motor neurons, thereby modulating the functions of ALS-associated RNA-binding proteins during the early phase of ALS. These findings provide the first evidence of a direct association between paraspeckle formation and a neurodegenerative disease, and may shed light on the development of novel therapeutic targets for the treatment of ALS.

Background: Dravet syndrome is a devastating infantile-onset epilepsy syndrome with cognitive deficits and autistic traits caused by genetic alterations in SCN1A gene encoding the α-subunit of the voltage-gated sodium channel Na(v)1.1. Disease modeling using patient-derived induced pluripotent stem cells (iPSCs) can be a powerful tool to reproduce this syndrome's human pathology. However, no such effort has been reported to date. We here report a cellular model for DS that utilizes patient-derived iPSCs., Results: We generated iPSCs from a Dravet syndrome patient with a c.4933C>T substitution in SCN1A, which is predicted to result in truncation in the fourth homologous domain of the protein (p.R1645*). Neurons derived from these iPSCs were primarily GABAergic (>50%), although glutamatergic neurons were observed as a minor population (<1%). Current-clamp analyses revealed significant impairment in action potential generation when strong depolarizing currents were injected., Conclusions: Our results indicate a functional decline in Dravet neurons, especially in the GABAergic subtype, which supports previous findings in murine disease models, where loss-of-function in GABAergic inhibition appears to be a main driver in epileptogenesis. Our data indicate that patient-derived iPSCs may serve as a new and powerful research platform for genetic disorders, including the epilepsies.

Background: The transplantation of neural stem/progenitor cells (NS/PCs) at the sub-acute phase of spinal cord injury, but not at the chronic phase, can promote functional recovery. However, the reasons for this difference and whether it involves the survival and/or fate of grafted cells under these two conditions remain unclear. To address this question, NS/PC transplantation was performed after contusive spinal cord injury in adult mice at the sub-acute and chronic phases., Results: Quantitative analyses using bio-imaging, which can noninvasively detect surviving grafted cells in living animals, revealed no significant difference in the survival rate of grafted cells between the sub-acute and chronic transplantation groups. Additionally, immunohistology revealed no significant difference in the differentiation phenotypes of grafted cells between the two groups. Microarray analysis revealed no significant differences in the expression of genes encoding inflammatory cytokines or growth factors, which affect the survival and/or fate of grafted cells, in the injured spinal cord between the sub-acute and chronic phases. By contrast, the distribution of chronically grafted NS/PCs was restricted compared to NS/PCs grafted at the sub-acute phase because a more prominent glial scar located around the lesion epicenter enclosed the grafted cells. Furthermore, microarray and histological analysis revealed that the infiltration of macrophages, especially M2 macrophages, which have anti-inflammatory role, was significantly higher at the sub-acute phase than the chronic phase. Ultimately, NS/PCs that were transplanted in the sub-acute phase, but not the chronic phase, promoted functional recovery compared with the vehicle control group., Conclusions: The extent of glial scar formation and the characteristics of inflammation is the most remarkable difference in the injured spinal cord microenvironment between the sub-acute and chronic phases. To achieve functional recovery by NS/PC transplantation in cases at the chronic phase, modification of the microenvironment of the injured spinal cord focusing on glial scar formation and inflammatory phenotype should be considered.

Background: Parkinson's disease (PD) is a neurodegenerative disease characterized by selective degeneration of dopaminergic neurons in the substantia nigra (SN). The familial form of PD, PARK2, is caused by mutations in the parkin gene. parkin-knockout mouse models show some abnormalities, but they do not fully recapitulate the pathophysiology of human PARK2., Results: Here, we generated induced pluripotent stem cells (iPSCs) from two PARK2 patients. PARK2 iPSC-derived neurons showed increased oxidative stress and enhanced activity of the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. iPSC-derived neurons, but not fibroblasts or iPSCs, exhibited abnormal mitochondrial morphology and impaired mitochondrial homeostasis. Although PARK2 patients rarely exhibit Lewy body (LB) formation with an accumulation of α-synuclein, α-synuclein accumulation was observed in the postmortem brain of one of the donor patients. This accumulation was also seen in the iPSC-derived neurons in the same patient., Conclusions: Thus, pathogenic changes in the brain of a PARK2 patient were recapitulated using iPSC technology. These novel findings reveal mechanistic insights into the onset of PARK2 and identify novel targets for drug screening and potential modified therapies for PD.