Neural stem/progenitor cells (NSCs/NPCs) give rise to neurons, astrocytes, and oligodendrocytes. It has become apparent that intracellular epigenetic modification including DNA methylation, in ...concert with extracellular cues such as cytokine signaling, is deeply involved in fate specification of NSCs/NPCs by defining cell-type specific gene expression. However, it is still unclear how differentiated neural cells retain their specific attributes by repressing cellular properties characteristic of other lineages. In previous work we have shown that methyl-CpG binding protein transcriptional repressors (MBDs), which are expressed predominantly in neurons in the central nervous system, inhibit astrocyte-specific gene expression by binding to highly methylated regions of their target genes. Here we report that oligodendrocytes, which do not express MBDs, can transdifferentiate into astrocytes both in vitro (cytokine stimulation) and in vivo (ischemic injury) through the activation of the JAK/STAT signaling pathway. These findings suggest that differentiation plasticity in neural cells is regulated by cell-intrinsic epigenetic mechanisms in collaboration with ambient cell-extrinsic cues.
Alpha‐synuclein is a major component of Lewy bodies, which are a histological hallmark of Parkinson's disease (PD). In this study, we investigated the dynamics of α‐synuclein during the early stage ...of immature dopaminergic neurons differentiated from human‐induced pluripotent stem cells derived from either a PD patient with SNCA triplication or a healthy donor.
Parkinson's disease (PD) is a neurodegenerative disorder caused by the selective loss of dopaminergic (DA) neurons in the substantia nigra pars compacta (SNc). Lewy bodies (LBs), another histological hallmark of PD, are observed in patients with familial or sporadic PD. The therapeutic potential of reducing the accumulation of α‐synuclein, a major LB component, has been investigated, but it remains unknown whether the formation of LBs results in the loss of DA neurons. PARK4 patients exhibit multiplication of the α‐synuclein gene (SNCA) without any pathological mutations, but their symptoms develop relatively early. Therefore, study of PARK4 might help elucidate the mechanism of α‐synuclein aggregation. In this study, we investigated the dynamics of α‐synuclein during the early stage of immature DA neurons, which were differentiated from human‐induced pluripotent stem cells (hiPSCs) derived from either a PARK4 patient with SNCA triplication or a healthy donor. We observed increased α‐synuclein accumulation in PARK4 hiPSC‐derived DA neurons relative to those derived from healthy donor hiPSCs. Interestingly, α‐synuclein accumulation disappeared over time in the PARK4 patient‐derived DA neurons. Moreover, an SNCA‐specific antisense oligonucleotide could reduce α‐synuclein levels during the accumulation stage. These observations may help reveal the mechanisms that regulate α‐synuclein levels, which may consequently be useful in the development of new therapies for patients with sporadic or familial PD.
Children's secure attachment with their primary caregivers is crucial for physical, cognitive, and emotional maturation. Yet, the causal links between specific parenting behaviors and infant ...attachment patterns are not fully understood. Here we report infant attachment in New World monkeys common marmosets, characterized by shared infant care among parents and older siblings and complex vocal communications. By integrating natural variations in parenting styles and subsecond-scale microanalyses of dyadic vocal and physical interactions, we demonstrate that marmoset infants signal their needs through context-dependent call use and selective approaches toward familiar caregivers. The infant attachment behaviors are tuned to each caregiver's parenting style; infants use negative calls when carried by rejecting caregivers and selectively avoid neglectful and rejecting caregivers. Family-deprived infants fail to develop such adaptive uses of attachment behaviors. With these similarities with humans, marmosets offer a promising model for investigating the biological mechanisms of attachment security.
Abstract Musashi (Msi) is an evolutionarily conserved gene family of RNA-binding proteins (RBPs) that is preferentially expressed in the nervous system. The first member of the Msi family was ...identified in Drosophila. Drosophila Msi plays an important role in regulating asymmetric cell division of the sensory organ precursor cells. The mammalian orthologs, including human and mouse Musashi1 (Msi1), are neural RBPs that are strongly expressed in fetal and adult neural stem/progenitor cells (NS/PCs). Mammalian Msi1 contributes to self renewal of NS/PCs through translational regulation of several target mRNAs. In this study, the zebrafish Msi ortholog zMsi1 was identified and characterized. The normal spatial and temporal expression profiles for both protein and mRNA were determined. A series of splice variants were detected. Overall, zMsi1 was strongly expressed in neural tissue in early stages of development and exhibited similarity to mammalian Msi1 expression patterns. To reveal the in vivo function of zMsi1, morpholinos against Msi1 were introduced into one-cell stage zebrafish embryos. Knock down of zmsi1 frequently resulted in aberrant formation of the Central Nervous System (CNS). These results suggest that Msi1 plays roles in CNS development in vertebrates. This article is part of a Special Issue entitled “RNA-Binding Proteins”.
To achieve the goal of a first-in-human trial for human induced pluripotent stem cell (hiPSC)-based transplantation for the treatment of various diseases, allogeneic human leukocyte antigen ...(HLA)-matched hiPSC cell banks represent a realistic tool from the perspective of quality control and cost performance. Furthermore, considering the limited therapeutic time-window for acute injuries, including neurotraumatic injuries, an iPS cell bank is of potential interest. However, due to the relatively immunoprivileged environment of the central nervous system, it is unclear whether HLA matching is required in hiPSC-derived neural stem/progenitor cell (hiPSC-NS/PC) transplantation for the treatment of neurodegenerative diseases and neurotraumatic injuries. In this study, we evaluated the significance of HLA matching in hiPSC-NS/PC transplantation by performing modified mixed lymphocyte reaction (MLR) assays with hiPSC-NS/PCs. Compared to fetus-derived NS/PCs, the expression levels of human leukocyte antigen-antigen D related (HLA-DR) and co-stimulatory molecules on hiPSC-NS/PCs were significantly low, even with the addition of tumor necrosis factor-α (TNFα) and/or interferon-γ (IFNγ) to mimic the inflammatory environment surrounding transplanted hiPSC-NS/PCs in injured tissues. Interestingly, both the allogeneic HLA-matched and the HLA-mismatched responses were similarly low in the modified MLR assay. Furthermore, the autologous response was also similar to the allogeneic response. hiPSC-NS/PCs suppressed the proliferative responses of allogeneic HLA-mismatched peripheral blood mononuclear cells (PBMCs) in a dose-dependent manner. Thus, the low antigen-presenting function and immunosuppressive effects of hiPSC-NS/PCs result in a depressed immune response, even in an allogeneic HLA-mismatched setting. It is crucial to verify whether these in vitro results are reproducible in a clinical setting.
•We performed modified MLR assays using hiPSC-NS/PCs derived from two human iPSC lines.•HLA-matched and -mismatched responses to allogeneic hiPSC-NS/PCs were equivalently low.•Autologous and allogeneic hiPSC-NS/PCs exerted similar effects on PBMC proliferation.•hiPSC-NS/PCs exhibited relatively low antigen-presenting function.•hiPSC-NS/PCs presented the suppressive effects on the proliferation of PBMCs.
Spinal cord injury (SCI) is a devastating condition with no established treatment. To better understand the pathology and develop a treatment modality for SCI, an understanding of the physiological ...changes following SCI at the molecular level is essential. However, studies on SCI have primarily used rodent models, and few studies have examined SCI in non-human primates. In this study, we analyzed the temporal changes in gene expression patterns following SCI in common marmosets (Callithrix jacchus) using microarray analysis and mRNA deep sequencing. This analysis revealed that, although the sequence of events is comparable between primates and rodents, the inflammatory response following SCI is significantly prolonged and the onset of glial scar formation is temporally delayed in primates compared with rodents. These observations indicate that the optimal time window to treat SCI significantly differs among different species. This study provides the first extensive analysis of gene expression following SCI in non-human primates and will serve as a valuable resource in understanding the pathology of SCI.
•The first global gene expression analysis of a primate SCI model•Temporal changes in gene expression following SCI in primates were analyzed.•The development of post-SCI changes is prolonged in primates compared with rodents.•This study may serve as a resource to investigate the pathology of SCI in primates.
Inflammatory cytokines cause tissue dysfunction. We previously reported that retinal inflammation down-regulates rhodopsin expression and impairs visual function by an unknown mechanism. Here, we ...demonstrate that rhodopsin levels were preserved by suppressor of cytokine signaling 3 (SOCS3), a negative feedback regulator of STAT3 activation. SOCS3 was expressed mainly in photoreceptor cells in the retina. In the SOCS3-deficient retinas, rhodopsin protein levels dropped sooner, and the reduction was more profound than in the wild type. Visual dysfunction, measured by electroretinogram, was prolonged in retina-specific SOCS3 conditional knock-out mice. Visual dysfunction and decreased rhodopsin levels both correlated with increased STAT3 activation enhanced by SOCS3 deficiency. Interleukin 6, one of the inflammatory cytokines found during retinal inflammation, activated STAT3 and decreased rhodopsin protein in adult retinal explants. This was enhanced by inhibiting SOCS3 function in vitro, indicating that rhodopsin reduction was not a secondary effect in the mutant mice. Interestingly, in the inflamed SOCS3-deficient adult retina, rhodopsin decreased post-transcriptionally at least partly through ubiquitin-proteasome-dependent degradation accelerated by STAT3 activation and not transcriptionally as in the developing retina, on which we reported previously. A STAT3-dependent E3 ubiquitin ligase, Ubr1, was responsible for rhodopsin degradation and was up-regulated in the inflamed SOCS3-deficient retinas. These results indicate that in wild-type animals, a decrease in rhodopsin during inflammation is minimized by endogenous SOCS3. However, when STAT3 activation exceeds some threshold beyond the compensatory activity of endogenous SOCS3, rhodopsin levels decrease. These findings suggest SOCS3 as a potential therapeutic target molecule for protecting photoreceptor cell function during inflammation.
The common marmoset (
) has attracted considerable attention, especially in the biomedical science and neuroscience research fields, because of its potential to recapitulate the complex and ...multidimensional phenotypes of human diseases, and several neurodegenerative transgenic models have been reported. However, there remain several issues as (i) it takes years to generate late-onset disease models, and (ii) the onset age and severity of phenotypes can vary among individuals due to differences in genetic background. In the present study, we established an efficient and rapid direct neuronal induction method (induced neurons; iNs) from embryonic and adult marmoset fibroblasts to investigate cellular-level phenotypes in the marmoset brain in vitro. We overexpressed reprogramming effectors, i.e., microRNA-9/9*, microRNA-124, and Achaete-Scute family bHLH transcription factor 1, in fibroblasts with a small molecule cocktail that facilitates neuronal induction. The resultant iNs from embryonic and adult marmoset fibroblasts showed neuronal characteristics within two weeks, including neuron-specific gene expression and spontaneous neuronal activity. As directly reprogrammed neurons have been shown to model neurodegenerative disorders, the neuronal reprogramming of marmoset fibroblasts may offer new tools for investigating neurological phenotypes associated with disease progression in non-human primate neurological disease models.
Sleep bruxism (SB) is classified as a sleep-related movement disorder characterized by grinding and clenching of the teeth during sleep, which is responsible for a variety of clinical problems such ...as abnormal tooth attrition and fracture of teeth or roots. Little is known about the etiology of SB. Our previous study identified a genomic association of the serotonin 2A receptor (5-HT2A) single nucleotide polymorphism (SNP), rs6313 C>T, with SB, where the C allele carrier is associated with a 4.25-fold increased risk of SB. Based on this finding, the aim of this study was to generate of neural cells using SB patient-specific induced pluripotent stem cells (iPSCs).
Two SB patients with C/C genotype of rs6313 and two controls with T/T genotype were screened by laboratory-based polysomnographic recordings and the TaqMan genotyping assay. Four lines of iPSCs, two from SB patients and two from controls, were established from peripheral blood mononuclear cells by introduction of reprogramming factors. We performed quality control assays on iPSCs using expression of markers for undifferentiated pluripotent cells, immunostaining for pluripotency markers, a three-germ layer assay, and karyotype analysis. The established iPSCs were differentiated into neurons using the neurosphere culture system. 5-HT2A gene expression in these neurons was evaluated by quantitative real-time PCR.
Patient-specific iPSCs were successfully differentiated into neurons expressing 5-HT2A.
This report is the first successful generation of neural cells using iPSCs from sleep bruxism patients with 5-HT2A polymorphism, which has the potential to elucidate the etiology and underlying mechanism of SB.
Musashi1 (Msi1) is an RNA-binding protein that is highly expressed in neural stem cells, and is considered to be a stemness factor. A known function of Msi1 is translational repression of ...specifically bound mRNAs. Although the basic mechanism and some target RNAs have been reported, further survey of interactors is necessary to understand the integrated function of Msi1. By screening using an mRNA display technique, we found that
doublecortin (
dcx) mRNA is a specific binding target of Msi1 in vitro. We confirmed that Msil repressed translation of a luciferase reporter gene linked to the selected 3′-untranslated region fragment of
dcx in Neuro2A cells.
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