The TLX-miR-219 cascade regulates neural stem cell proliferation in neurodevelopment and schizophrenia iPSC model

Haloperidol, Olanzapine, and Risperidone Induce Morphological Changes in an In Vitro Model of Human Hippocampal Neurogenesis

BACKGROUND

Induced pluripotent stem cell (iPSC) based neuronal differentiation is valuable for studying neuropsychiatric disorders and pharmacological mechanisms at the cellular level. We aimed to examine the effects of typical and atypical antipsychotics on human iPSC-derived neural progenitor cells (NPCs).

METHODS

Proliferation and neurite outgrowth were measured by live cell imaging, and gene expression levels related to neuronal identity were analyzed by RT-QPCR and immunocytochemistry during differentiation into hippocampal dentate gyrus granule cells following treatment of low- and high-dose antipsychotics (haloperidol, olanzapine, and risperidone).

RESULTS

Antipsychotics did not modify the growth properties of NPCs after 3 days of treatment. However, the characteristics of neurite outgrowth changed significantly in response to haloperidol and olanzapine. After three weeks of differentiation, mRNA expression levels of the selected neuronal markers increased (except for MAP2), while antipsychotics caused only subtle changes. Additionally, we found no changes in MAP2 or GFAP protein expression levels as a result of antipsychotic treatment.

CONCLUSIONS

Altogether, antipsychotic medications promoted neurogenesis in vitro by influencing neurite outgrowth rather than changing cell survival or gene expression. This study provides insights into the effects of antipsychotics on neuronal differentiation and highlights the importance of considering neurite outgrowth as a potential target of action.

Environmental enrichment attenuates depressive-like behavior in maternal rats by inhibiting neuroinflammation and apoptosis and promoting neuroplasticity

Gestational stress can exacerbate postpartum depression (PPD), for which treatment options remain limited. Environmental enrichment (EE) may be a therapeutic intervention for neuropsychiatric disorders, including depression, but the specific mechanisms by which EE might impact PPD remain unknown. Here we examined the behavioral, molecular, and cellular impact of EE in a stable PPD model in rats developed through maternal separation (MS). Maternal rats subjected to MS developed depression-like behavior and cognitive dysfunction together with evidence of significant neuroinflammation including microglia activation, neuronal apoptosis, and impaired synaptic plasticity. Expanding the duration of EE to throughout pregnancy and lactation, we observed an EE-associated reversal of MS-induced depressive phenotypes, inhibition of neuroinflammation and neuronal apoptosis, and improvement in synaptic plasticity in maternal rats. Thus, EE effectively alleviates neuroinflammation, neuronal apoptosis, damage to synaptic plasticity, and consequent depression-like behavior in mother rats experiencing MS-induced PPD, paving the way for new preventive and therapeutic strategies for PPD.

Induced pluripotent stem cells (iPSCs): molecular mechanisms of induction and applications

The induced pluripotent stem cell (iPSC) technology has transformed in vitro research and holds great promise to advance regenerative medicine. iPSCs have the capacity for an almost unlimited expansion, are amenable to genetic engineering, and can be differentiated into most somatic cell types. iPSCs have been widely applied to model human development and diseases, perform drug screening, and develop cell therapies. In this review, we outline key developments in the iPSC field and highlight the immense versatility of the iPSC technology for in vitro modeling and therapeutic applications. We begin by discussing the pivotal discoveries that revealed the potential of a somatic cell nucleus for reprogramming and led to successful generation of iPSCs. We consider the molecular mechanisms and dynamics of somatic cell reprogramming as well as the numerous methods available to induce pluripotency. Subsequently, we discuss various iPSC-based cellular models, from mono-cultures of a single cell type to complex three-dimensional organoids, and how these models can be applied to elucidate the mechanisms of human development and diseases. We use examples of neurological disorders, coronavirus disease 2019 (COVID-19), and cancer to highlight the diversity of disease-specific phenotypes that can be modeled using iPSC-derived cells. We also consider how iPSC-derived cellular models can be used in high-throughput drug screening and drug toxicity studies. Finally, we discuss the process of developing autologous and allogeneic iPSC-based cell therapies and their potential to alleviate human diseases.

Quiescent Adult Neural Stem Cells: Developmental Origin and Regulatory Mechanisms

The existence of neural stem cells (NSCs) in the adult mammalian nervous system, although small in number and restricted to the sub-ventricular zone of the lateral ventricles, the dentate gyrus of the hippocampus, and the olfactory epithelium, is a gift of evolution for the adaptive brain function which requires persistent plastic changes of these regions. It is known that most adult NSCs are latent, showing long cell cycles. In the past decade, the concept of quiescent NSCs (qNSCs) has been widely accepted by researchers in the field, and great progress has been made in the biology of qNSCs. Although the spontaneous neuronal regeneration derived from adult NSCs is not significant, understanding how the behaviors of qNSCs are regulated sheds light on stimulating endogenous NSC-based neuronal regeneration. In this review, we mainly focus on the recent progress of the developmental origin and regulatory mechanisms that maintain qNSCs under normal conditions, and that mobilize qNSCs under pathological conditions, hoping to give some insights for future study.

Identification of novel NRF2-dependent genes as regulators of lead and arsenic toxicity in neural progenitor cells

Lead (Pb) and arsenic (As) are prevalent metal contaminants in the environment. Exposures to these metals are associated with impaired neuronal functions and adverse effects on neurodevelopment in children. However, the molecular mechanisms by which Pb and As impair neuronal functions remain poorly understood. Here, we identified F2RL2, TRIM16L, and PANX2 as novel targets of Nuclear factor erythroid 2-related factor 2 (NRF2)-the master transcriptional factor for the oxidative stress response-that are commonly upregulated with both Pb and As in human neural progenitor cells (NPCs). Using a ChIP (Chromatin immunoprecipitation)-qPCR assay, we showed that NRF2 directly binds to the promoter region of F2RL2, TRIM16L, and PANX2 to regulate expression of these genes. We demonstrated that F2RL2, PANX2, and TRIM16L have differential effects on cell death, proliferation, and differentiation of NPCs in both the presence and absence of metal exposures, highlighting their roles in regulating NPC function. Furthermore, the analyses of the transcriptomic data on NPCs derived from autism spectrum disorder (ASD) patients revealed that dysregulation of F2RL2, TRIM16L, and PANX2 was associated with ASD genetic backgrounds and ASD risk genes. Our findings revealed that Pb and As induce a shared NRF2-dependent transcriptional response in NPCs and identified novel genes regulating NPC function. While further in vivo studies are warranted, this study provides a novel mechanism linking metal exposures to NPC function and identifies potential genes of interest in the context of neurodevelopment.

Genetics of human brain development

Brain development in humans is achieved through precise spatiotemporal genetic control, the mechanisms of which remain largely elusive. Recently, integration of technological advances in human stem cell-based modelling with genome editing has emerged as a powerful platform to establish causative links between genotypes and phenotypes directly in the human system. Here, we review our current knowledge of complex genetic regulation of each key step of human brain development through the lens of evolutionary specialization and neurodevelopmental disorders and highlight the use of human stem cell-derived 2D cultures and 3D brain organoids to investigate human-enriched features and disease mechanisms. We also discuss opportunities and challenges of integrating new technologies to reveal the genetic architecture of human brain development and disorders.

Advances in the understanding of the pathophysiology of schizophrenia and bipolar disorder through induced pluripotent stem cell models

The pathophysiology of schizophrenia and bipolar disorder involves a complex interaction between genetic and environmental factors that begins in the early stages of neurodevelopment. Recent advancements in the field of induced pluripotent stem cells (iPSCs) offer a promising tool for understanding the neurobiological alterations involved in these disorders and, potentially, for developing new treatment options. In this review, we summarize the results of iPSC-based research on schizophrenia and bipolar disorder, showing disturbances in neurodevelopmental processes, imbalance in glutamatergic-GABAergic transmission and neuromorphological alterations. The limitations of the reviewed literature are also highlighted, particularly the methodological heterogeneity of the studies, the limited number of studies developing iPSC models of both diseases simultaneously, and the lack of in-depth clinical characterization of the included samples. Further studies are needed to advance knowledge on the common and disease-specific pathophysiological features of schizophrenia and bipolar disorder and to promote the development of new treatment options.

Specific downregulation of microRNA-186 induces neural stem cell self-renewal by upregulating Bmi-1/FoxG1 expression

Self-renewal and differentiation in neural stem cells (NSCs) are modulated by microRNAs (miRNAs). However, the recent evidence available is not enough to elucidate the role of miRNA in the self-renewal and differentiation of NSCs from developing brain. In this study, we isolated primary NSCs from the forebrain of fetal rat for in vitro analysis. Downregulation of miRNA-186 in response to a specific miRNA inhibitor resulted in upregulation of Bmi-1 and FoxG1, while maintaining NCS self-renewal. Bmi-1 overexpression restored the maintenance of NSCs in vitro. FoxG1 was found to promote the methylation of Foxo3 promoter and inhibited Foxo3 expression. miR-186 upregulation increased the expression of Foxo3 and inhibited NSC self-renewal in the absence of Foxo3. Therefore, we propose that downregulation of miR-186 maintained NSC self-renewal in the postnatal brain by upregulating the Bmi1/FoxG1 expression via FoxO3 elevation.

The emerging role of exosomes in Schizophrenia

Schizophrenia (SCZ), a serious mental disorder, is one of the leading causes of disease burden worldwide. Exosomes, as a natural nanocarrier, are able to cross the blood-brain barrier (BBB) and play a key bridging role in central nervous system (CNS) communication, participating in important physiological processes such as neural regeneration, prominent plasticity, axonal support, and neuroinflammation. In recent years, exosomes have received widespread attention in the field of neurodegenerative diseases and mental disorders, especially Alzheimer's disease. However, there are few reviews on exosomes and SCZ. Therefore, we conducted a literature search in PubMed and Web of Science using the following search terms: "schizophrenia", "mental disorder", "central system", "exosome", "extracellular vesicles" to identify publications from January 2010 to December 2022. Our review summarized exosomes secreted by different cell types in the CNS and the double-edged role of exosomes in the development of SCZ, and discussed their future potential as biomarkers and therapeutic targets. In conclusion, this article provides an up-to-date overview of the current research on the involvement of exosomes in SCZ, while also highlighting the challenges that are currently faced in this field.

Comparison of Oncogenes, Tumor Suppressors, and MicroRNAs Between Schizophrenia and Glioma: The Balance of Power

The risk of cancer in schizophrenia has been controversial. Confounders of the issue are cigarette smoking in schizophrenia, and antiproliferative effects of antipsychotic medications. The author has previously suggested comparison of a specific cancer like glioma to schizophrenia might help determine a more accurate relationship between cancer and schizophrenia. To accomplish this goal, the author performed three comparisons of data; the first a comparison of conventional tumor suppressors and oncogenes between schizophrenia and cancer including glioma. This comparison determined schizophrenia has both tumor-suppressive and tumor-promoting characteristics. A second, larger comparison between brain-expressed microRNAs in schizophrenia with their expression in glioma was then performed. This identified a core carcinogenic group of miRNAs in schizophrenia offset by a larger group of tumor-suppressive miRNAs. This proposed "balance of power" between oncogenes and tumor suppressors could cause neuroinflammation. This was assessed by a third comparison between schizophrenia, glioma and inflammation in asbestos-related lung cancer and mesothelioma (ALRCM). This revealed that schizophrenia shares more oncogenic similarity to ALRCM than glioma.

MicroRNA Profiling of Self-Renewing Human Neural Stem Cells Reveals Novel Sets of Differentially Expressed microRNAs During Neural Differentiation In Vitro

The involvement of microRNAs (miRNAs) in orchestrating self-renewal and differentiation of stem cells has been revealed in a number of recent studies. And while in human pluripotent stem cells, miRNAs have been directly linked to the core pluripotency network, including the cell cycle regulation and the maintenance of the self-renewing capacity, their role in the onset of differentiation in other contexts, such as determination of neural cell fate, remains poorly described. To bridge this gap, we used three model cell types to study miRNA expression patterns: human embryonic stem cells (hESCs), hESCs-derived self-renewing neural stem cells (NSCs), and differentiating NSCs. The comprehensive miRNA profiling presented here reveals novel sets of miRNAs differentially expressed during human neural cell fate determination in vitro. Furthermore, we report a miRNA expression profile of self-renewing human NSCs, which has been lacking to this date. Our data also indicates that miRNA clusters enriched in NSCs share the target-determining seed sequence with cell cycle regulatory miRNAs expressed in pluripotent hESCs. Lastly, our mechanistic experiments confirmed that cluster miR-17-92, one of the NSCs-enriched clusters, is directly transcriptionally regulated by transcription factor c-MYC.

Supt16 haploinsufficiency causes neurodevelopment disorder by disrupting MAPK pathway in neural stem cells

Chromatin regulators constitute a fundamental means of transcription regulation, which have been implicated in neurodevelopment and neurodevelopment disorders (NDDs). Supt16, one of candidate genes for NDDs, encodes the large subunit of facilitates chromatin transcription. However, the underlying mechanisms remain poorly understood. Here, Supt16+/- mice was generated, modeling the neurodevelopment disorder. Abnormal cognitive and social behavior was observed in the Supt16  +/- mice. Simultaneously, the number of neurocytes in the cerebral cortex and hippocampus is decreased, which might be resulted from the impairment of mouse neural stem cells (mNSCs) in the SVZ. Supt16 haploinsufficiency affects the proliferation and apoptosis of mNSCs. As the RNA-seq and chromatic immunoprecipitation sequencing assays showed, Supt16 haploinsufficiency disrupts the stemness of mNSCs by inhibiting MAPK signal pathway. Thus, this study demonstrates a critical role of Supt16 gene in the proliferation and apoptosis of mNSCs and provides a novel insight in the pathogenesis of NDDs.

MiR-181a-5p promotes neural stem cell proliferation and enhances the learning and memory of aged mice

Hippocampal neural stem cell (NSC) proliferation is known to decline with age, which is closely linked to learning and memory impairments. In the current study, we found that the expression level of miR-181a-5p was decreased in the hippocampal NSCs of aged mice and that exogenous overexpression of miR-181a-5p promoted NSC proliferation without affecting NSC differentiation into neurons and astrocytes. The mechanistic study revealed that phosphatase and tensin homolog (PTEN), a negative regulator of the AKT signaling pathway, was the target of miR-181a-5p and knockdown of PTEN could rescue the impairment of NSC proliferation caused by low miR-181a-5p levels. Moreover, overexpression of miR-181a-5p in the dentate gyrus enhanced the proliferation of NSCs and ameliorated learning and memory impairments in aged mice. Taken together, our findings indicated that miR-181a-5p played a functional role in NSC proliferation and aging-related, hippocampus-dependent learning and memory impairments.

Supt16 Haploinsufficiency Impairs PI3K/AKT/mTOR/Autophagy Pathway in Human Pluripotent Stem Cells Derived Neural Stem Cells

The maintenance of neural stem cells (NSCs) plays a critical role in neurodevelopment and has been implicated in neurodevelopmental disorders (NDDs). However, the underlying mechanisms linking defective human neural stem cell self-renewal to NDDs remain undetermined. Our previous study found that Supt16 haploinsufficiency causes cognitive and social behavior deficits by disrupting the stemness maintenance of NSCs in mice. However, its effects and underlying mechanisms have not been elucidated in human neural stem cells (hNSCs). Here, we generated Supt16^+/- induced pluripotent stem cells (iPSCs) and induced them into hNSCs. The results revealed that Supt16 heterozygous hNSCs exhibit impaired proliferation, cell cycle arrest, and increased apoptosis. As the RNA-seq analysis showed, Supt16 haploinsufficiency inhibited the PI3K/AKT/mTOR pathway, leading to rising autophagy, and further resulted in the dysregulated expression of multiple proteins related to cell proliferation and apoptotic process. Furthermore, the suppression of Supt16 heterozygous hNSC self-renewal caused by autophagy activation could be rescued by MHY1485 treatment or reproduced in rapamycin-treated hNSCs. Thus, our results showed that Supt16 was essential for hNSC self-renewal and its haploinsufficiency led to cell cycle arrest, impaired cell proliferation, and increased apoptosis of hNSCs by regulating the PI3K/AKT/mTOR/autophagy pathway. These provided a new insight to understand the causality between the Supt16 heterozygous NSCs and NDDs in humans.

Current advancements of modelling schizophrenia using patient-derived induced pluripotent stem cells

Schizophrenia (SZ) is a severe psychiatric disorder, with a prevalence of 1-2% world-wide and substantial health- and social care costs. The pathology is influenced by both genetic and environmental factors, however the underlying cause still remains elusive. SZ has symptoms including delusions, hallucinations, confused thoughts, diminished emotional responses, social withdrawal and anhedonia. The onset of psychosis is usually in late adolescence or early adulthood. Multiple genome-wide association and whole exome sequencing studies have provided extraordinary insights into the genetic variants underlying familial as well as polygenic forms of the disease. Nonetheless, a major limitation in schizophrenia research remains the lack of clinically relevant animal models, which in turn hampers the development of novel effective therapies for the patients. The emergence of human induced pluripotent stem cell (hiPSC) technology has allowed researchers to work with SZ patient-derived neuronal and glial cell types in vitro and to investigate the molecular basis of the disorder in a human neuronal context. In this review, we summarise findings from available studies using hiPSC-based neural models and discuss how these have provided new insights into molecular and cellular pathways of SZ. Further, we highlight different examples of how these models have shown alterations in neurogenesis, neuronal maturation, neuronal connectivity and synaptic impairment as well as mitochondrial dysfunction and dysregulation of miRNAs in SZ patient-derived cultures compared to controls. We discuss the pros and cons of these models and describe the potential of using such models for deciphering the contribution of specific human neural cell types to the development of the disease.

The Role of Bone Morphogenetic Protein Receptor Type 2 (BMPR2) and the Prospects of Utilizing Induced Pluripotent Stem Cells (iPSCs) in Pulmonary Arterial Hypertension Disease Modeling

Pulmonary arterial hypertension (PAH) is a progressive disease characterized by increased pulmonary vascular resistance (PVR), causing right ventricular hypertrophy and ultimately death from right heart failure. Heterozygous mutations in the bone morphogenetic protein receptor type 2 (BMPR2) are linked to approximately 80% of hereditary, and 20% of idiopathic PAH cases, respectively. While patients carrying a BMPR2 gene mutation are more prone to develop PAH than non-carriers, only 20% will develop the disease, whereas the majority will remain asymptomatic. PAH is characterized by extreme vascular remodeling that causes pulmonary arterial endothelial cell (PAEC) dysfunction, impaired apoptosis, and uncontrolled proliferation of the pulmonary arterial smooth muscle cells (PASMCs). To date, progress in understanding the pathophysiology of PAH has been hampered by limited access to human tissue samples and inadequacy of animal models to accurately mimic the pathogenesis of human disease. Along with the advent of induced pluripotent stem cell (iPSC) technology, there has been an increasing interest in using this tool to develop patient-specific cellular models that precisely replicate the pathogenesis of PAH. In this review, we summarize the currently available approaches in iPSC-based PAH disease modeling and explore how this technology could be harnessed for drug discovery and to widen our understanding of the pathophysiology of PAH.

Multi-target cell therapy using a magnetoelectric microscale biorobot for targeted delivery and selective differentiation of SH-SY5Y cells via magnetically driven cell stamping

Cell therapy refers to a treatment that involves the delivery of cells or cellular material by means of injection, grafting, or implantation in order to replace damaged tissue and restore its function, or to aid the body in fighting disease. However, limitations include poor targeting delivery and low therapeutic efficacy due to low cell survival. Hence, novel approaches are required to increase cell delivery efficiency and enhance therapeutic efficacy via selective cell differentiation at target areas. Here, we present a stamping magnetoelectric microscale biorobot (SMMB) consisting of neuron-like cell spheroids loaded with magnetoelectric nanoparticles. The SMMB enables not only effective targeted delivery of cells to multiple target areas (via minimally invasive stamping employing magnetic actuation) but also facilitates selective neuronal differentiation via magnetoelectric (ME) stimulation. This ensures rapid colonization and enhances efficacy. SMMBs were fabricated using SH-SY5Y cells. Magnetoelectric nanoparticles for ME stimulation responded to an alternating magnetic field that ensured targeted cell differentiation. Multi-target cell therapy facilitated the targeted delivery and selective differentiation of SH-SY5Y cells to multiple regions using a single SMMB with rotating and alternating magnetic fields for delivery and ME stimulation. This promising tool may overcome the limitations of existing cell therapy for neurodegenerative diseases.

MicroRNAs and Synaptic Plasticity: From Their Molecular Roles to Response to Therapy

Synaptic plasticity is the ability of synapses to weaken or strengthen over time, in response to changes in the activity of the neurons. It is orchestrated by a variety of genes, proteins, and external and internal factors, especially epigenetic factors. MicroRNAs (miRNAs) are well-acknowledged epigenetic modulators that regulate the translation and degradation of target genes in the nervous system. Increasing evidence has suggested that a number of miRNAs play important roles in modulating various aspects of synaptic plasticity. The deregulation of miRNAs could be associated with pathological alterations in synaptic plasticity, which could lead to different CNS-related diseases. Herein, we provide an update on the role of miRNAs in governing synaptic plasticity. In addition, we also summarize recent researches on the role of miRNAs in drug addiction, and their targets and mechanism of action. Understanding of the way in which miRNAs contribute to synaptic plasticity provides rational clues in establishing the novel biomarkers and new therapeutic strategies for the diagnosis and treatment of plasticity-related diseases and drug addiction.

Effects of exosomes on adult hippocampal neurogenesis and neuropsychiatric disorders

Exosomes are extracellular vesicles originating from the endosomal system, which are involved in intercellular substance transfer and cell waste elimination. Recent studies implicate the roles of exosomes in adult hippocampal neurogenesis, a process through which new granule cells are generated in the dentate gyrus, and which is closely related to mood and cognition, as well as psychiatric disorders. As such, exosomes are recognized as potential biomarkers of neurologic and psychiatric disorders. This review briefly introduces the synthesis and secretion mechanism of exosomes, and discuss the relationship between exosomes and hippocampal neurogenesis, and their roles in regulating depression, epilepsy and schizophrenia. Finally, we discuss the prospects of their application in diagnosing disorders of the central nervous system (CNS).

MicroRNA profile as potential molecular signature for attention deficit hyperactivity disorder in children

AIMS

Attention deficit/hyperactivity disorder (ADHD) is a prevalent disorder of neurodevelopment in children. The diagnosis of ADHD mainly relies on the symptoms and some may be misdiagnosed due to age-based variation in behaviours. This study aimed to explore biomarkers that are greatly needed for the accurate diagnosis of ADHD.

METHODS

742 samples were retrospectively investigated in 3 independent cohorts, screening, training, and validation, for circulation microRNA measurement using microarray, Taqman polymerase chain reaction and regression analysis.

RESULTS

A panel of five miRNAs (miR-4516, miR-6090, miR-4763-3p, miR-4281 and miR-4466) were identified as ADHD independent risk factors that provided a high diagnostic accuracy and specificity of ADHD (AUC =0.940 and 0.927 in the training and validation datasets, respectively). This panel of miRNAs differentiated ADHD well from control groups. After clinical improvement by treatment, the panel of miRNAs in patients and AUC changed significantly, and were close to those in healthy controls. Importantly, the targets of the miRNAs identified were commonly enriched in receptor signalling pathways, ion channels and synapse structures.

CONCLUSION

Our study identified a useful panel of miRNAs that have considerable clinical value in evaluating ADHD and provide important evidence for aberrant epigenetic regulation in ADHD.

Schizophrenia is defined by cell-specific neuropathology and multiple neurodevelopmental mechanisms in patient-derived cerebral organoids

Due to an inability to ethically access developing human brain tissue as well as identify prospective cases, early-arising neurodevelopmental and cell-specific signatures of Schizophrenia (Scz) have remained unknown and thus undefined. To overcome these challenges, we utilized patient-derived induced pluripotent stem cells (iPSCs) to generate 3D cerebral organoids to model neuropathology of Scz during this critical period. We discovered that Scz organoids exhibited ventricular neuropathology resulting in altered progenitor survival and disrupted neurogenesis. This ultimately yielded fewer neurons within developing cortical fields of Scz organoids. Single-cell sequencing revealed that Scz progenitors were specifically depleted of neuronal programming factors leading to a remodeling of cell-lineages, altered differentiation trajectories, and distorted cortical cell-type diversity. While Scz organoids were similar in their macromolecular diversity to organoids generated from healthy controls (Ctrls), four GWAS factors (PTN, COMT, PLCL1, and PODXL) and peptide fragments belonging to the POU-domain transcription factor family (e.g., POU3F2/BRN2) were altered. This revealed that Scz organoids principally differed not in their proteomic diversity, but specifically in their total quantity of disease and neurodevelopmental factors at the molecular level. Single-cell sequencing subsequently identified cell-type specific alterations in neuronal programming factors as well as a developmental switch in neurotrophic growth factor expression, indicating that Scz neuropathology can be encoded on a cell-type-by-cell-type basis. Furthermore, single-cell sequencing also specifically replicated the depletion of BRN2 (POU3F2) and PTN in both Scz progenitors and neurons. Subsequently, in two mechanistic rescue experiments we identified that the transcription factor BRN2 and growth factor PTN operate as mechanistic substrates of neurogenesis and cellular survival, respectively, in Scz organoids. Collectively, our work suggests that multiple mechanisms of Scz exist in patient-derived organoids, and that these disparate mechanisms converge upon primordial brain developmental pathways such as neuronal differentiation, survival, and growth factor support, which may amalgamate to elevate intrinsic risk of Scz.

TLX, an Orphan Nuclear Receptor With Emerging Roles in Physiology and Disease

TLX (NR2E1), an orphan member of the nuclear receptor superfamily, is a transcription factor that has been described to be generally repressive in nature. It has been implicated in several aspects of physiology and disease. TLX is best known for its ability to regulate the proliferation of neural stem cells and retinal progenitor cells. Dysregulation, overexpression, or loss of TLX expression has been characterized in numerous studies focused on a diverse range of pathological conditions, including abnormal brain development, psychiatric disorders, retinopathies, metabolic disease, and malignant neoplasm. Despite the lack of an identified endogenous ligand, several studies have described putative synthetic and natural TLX ligands, suggesting that this receptor may serve as a therapeutic target. Therefore, this article aims to briefly review what is known about TLX structure and function in normal physiology, and provide an overview of TLX in regard to pathological conditions. Particular emphasis is placed on TLX and cancer, and the potential utility of this receptor as a therapeutic target.

Induced pluripotent stem cells for 2D and 3D modelling the biological basis of schizophrenia and screening possible therapeutics

Induced pluripotent stem cells (iPSCs) are providing unprecedented insight into complex neuropsychiatric disorders such as schizophrenia (SZ). Here we review the use of iPSCs for investigating the etiopathology and treatment of SZ, beginning with conventional in vitro two-dimensional (2D; monolayer) cell modelling, through to more advanced 3D tissue studies. With the advent of 3D modelling, utilising advanced differentiation paradigms and additive manufacturing technologies, inclusive of patient-specific cerebral/neural organoids and bioprinted neural tissues, such live disease-relevant tissue systems better recapitulate "within-body" tissue function and pathobiology. We posit that by enabling better understanding of biological causality, these evolving strategies will yield novel therapeutic targets and accordingly, drug candidates.

Genetic variants in miRNAs differentially expressed during brain development and their relevance to psychiatric disorders susceptibility

OBJECTIVES

MicroRNAs (miRNAs) play an important regulatory role in the expression of genes involved in brain functions during development. Genetic variants in miRNA genes may impact their regulatory function and lead to psychiatric disorders. To evaluate the role of genetic variants in genes of miRNAs differentially expressed during neurodevelopment on autism spectrum disorder (ASD), attention deficit/hyperactivity disorder (ADHD), schizophrenia (SCZ), and major depressive disorder (MDD).

METHODS

The miRNAs were identified in the literature. Summary statistics from the most recent genome-wide association studies to date were used to evaluate the association between the selected polymorphisms and each disorder in a look-up approach. In a global analysis, we compared the standardised risk effect of variants in neurodevelopment-related miRNAs with those in the remaining miRNAs from miRBase.

RESULTS

The global analysis showed that variants in neurodevelopment-related miRNAs had higher risk effects compared to the other miRNAs for SCZ (p = 0.010) and ADHD (p = 0.001). MIR33B, MIR29B2, MIR29C, MIR137, and MIR135A1 were significantly associated with SCZ, while 55.9% of the miRNAs were at least nominally associated with one or more psychiatric disorders (p < 0.05).

CONCLUSIONS

Genetic variants in neurodevelopment-related miRNAs play an important role in the genetic susceptibility of psychiatric disorders, mainly SCZ and ADHD.

miR-219 overexpressing oligodendrocyte progenitor cells for treating compression spinal cord injury

Oligodendrocyte progenitor cells (OPCs) transplantation has been considered a promising treatment for spinal cord injury, according to previous studies. Recent research shed light on the importance of microRNA 219 (miR-219) in oligodendrocyte development, so here miR-219-overexpressing OPCs (miR-219 OPCs) were transplanted in animal models of spinal cord injury to evaluate the impact of miR-219 on oligodendrocyte differentiation and functional recovery in vivo. Our findings demonstrate that transplanted cells were distributed in the tissue sections and contributed to reducing the size of cavity in the injury site. Interestingly, miR-219 promoted OPC differentiation into mature oligodendrocyte expressing MBP in vivo whereas in absence of miR-219, less number of cells differentiated into mature oligodendrocytes. An eight week evaluation using the Basso Beattie Bresnahan (BBB) locomotor test confirmed improvement in functional recovery of hind limbs. Overall, this study demonstrated that miR-219 promoted differentiation and maturation of OPCs after transplantation and can be used in cell therapy of spinal cord injury.

IgGs-Abzymes from the Sera of Patients with Multiple Sclerosis Recognize and Hydrolyze miRNAs

Autoantibodies-abzymes hydrolyzing DNA, myelin basic protein, and oligosaccharides have been revealed in the sera of patients with multiple sclerosis (MS). In MS, specific microRNAs are found in blood and cerebrospinal fluid, which are characterized by increased expression. Autoantibodies, specifically hydrolyzing four different miRNAs, were first detected in the blood of schizophrenia patients. Here, we present the first evidence that 23 IgG antibodies of MS patients effectively recognize and hydrolyze four neuroregulatory miRNAs (miR-137, miR-9-5p, miR-219-2-3p, and miR-219-5p) and four immunoregulatory miRNAs (miR-21-3p, miR-146a-3p, miR-155-5p, and miR-326). Several known criteria were checked to show that the recognition and hydrolysis of miRNAs is an intrinsic property of MS IgGs. The hydrolysis of all miRNAs is mostly site-specific. The major and moderate sites of the hydrolysis of each miRNA for most of the IgG preparations coincided; however, some of them showed other specific sites of splitting. Several individual IgGs hydrolyzed some miRNAs almost nonspecifically at nearly all internucleoside bonds or demonstrated a combination of site-specific and nonspecific splitting. Maximum average relative activity (RA) was observed in the hydrolysis of miR-155-5p for IgGs of patients of two types of MS-clinically isolated syndrome and relapsing-remitting MS-but was also high for patients with primary progressive and secondary progressive MS. Differences between RAs of IgGs of four groups of MS patients and healthy donors were statistically significant (p < 0.015). There was a tendency of decreasing efficiency of hydrolysis of all eight miRNAs during remission compared with the exacerbation of the disease.

MicroRNA 219-5p inhibits alveolarization by reducing platelet derived growth factor receptor-alpha

BACKGROUND

MicroRNA (miR) are small conserved RNA that regulate gene expression post-transcription. Previous genome-wide analysis studies in preterm infants indicate that pathways of miR 219-5p are important in infants with Bronchopulmonary Dysplasia (BPD).

METHODS

Here we report a prospective cohort study of extremely preterm neonates wherein infants diagnosed with severe BPD expressed increased airway miR-219-5p and decreased platelet derived growth factor receptor alpha (PDGFR-α), a target of mir-219-5p and a key regulator of alveolarization, compared to post-conception age-matched term infants.

RESULTS

miR-219-5p was highly expressed in the pulmonary epithelial lining in lungs of infants with BPD by in situ hybridization of human infant lungs. In both in vitro and in vivo (mouse) models of BPD, miR-219-5p was increased on exposure to hyperoxia compared with the normoxia control, with a complementary decrease of PDGFR-α. To further confirm the target relationship between miR-219 and PDGFR-α, pulmonary epithelial cells (MLE12) and lung primary fibroblasts were treated with a mimic of miR-219-5p and a locked nucleic acid (LNA) based inhibitor of miR-219-5p. In comparison with the control group, the level of miR-219 increased significantly after miR-219 mimic treatment, while the level of PDGFR-α declined markedly. LNA exposure increased PDGFR-α. Moreover, in BPD mouse model, over-expression of miR-219-5p inhibited alveolar development, indicated by larger alveolar spaces accompanied by reduced septation.

CONCLUSIONS

Taken together, our results demonstrate that increased miR-219-5p contributes to the pathogenesis of BPD by targeting and reducing PDGFR-α. The use of specific miRNA antagonists may be a therapeutic strategy for preventing the development of BPD.

Neuronal Development-Related miRNAs as Biomarkers for Alzheimer's Disease, Depression, Schizophrenia and Ionizing Radiation Exposure

Radiation exposure may induce Alzheimer's disease (AD), depression or schizophrenia. A number of experimental and clinical studies suggest the involvement of miRNA in the development of these diseases, and also in the neuropathological changes after brain radiation exposure. The current literature review indicated the involvement of 65 miRNAs in neuronal development in the brain. In the brain tissue, blood, or cerebral spinal fluid (CSF), 11, 55, or 28 miRNAs are involved in the development of AD respectively, 89, 50, 19 miRNAs in depression, and 102, 35, 8 miRNAs in schizophrenia. We compared miRNAs regulating neuronal development to those involved in the genesis of AD, depression and schizophrenia and also those driving radiation-induced brain neuropathological changes by reviewing the available data. We found that 3, 11, or 8 neuronal developmentrelated miRNAs from the brain tissue, 13, 16 or 14 miRNAs from the blood of patient with AD, depression and schizophrenia respectively were also involved in radiation-induced brain pathological changes, suggesting a possibly specific involvement of these miRNAs in radiation-induced development of AD, depression and schizophrenia respectively. On the other hand, we noted that radiationinduced changes of two miRNAs, i.e., miR-132, miR-29 in the brain tissue, three miRNAs, i.e., miR- 29c-5p, miR-106b-5p, miR-34a-5p in the blood were also involved in the development of AD, depression and schizophrenia, thereby suggesting that these miRNAs may be involved in the common brain neuropathological changes, such as impairment of neurogenesis and reduced learning memory ability observed in these three diseases and also after radiation exposure.

Functional Comparison of Blood-Derived Human Neural Progenitor Cells

Induced pluripotent stem cell (iPSC)-derived neural progenitor cells (NPCs) are promising tools to model complex neurological or psychiatric diseases, including schizophrenia. Multiple studies have compared patient-derived and healthy control NPCs derived from iPSCs in order to investigate cellular phenotypes of this disease, although the establishment, stabilization, and directed differentiation of iPSC lines are rather expensive and time-demanding. However, interrupted reprogramming by omitting the stabilization of iPSCs may allow for the generation of a plastic stage of the cells and thus provide a shortcut to derive NPSCs directly from tissue samples. Here, we demonstrate a method to generate shortcut NPCs (sNPCs) from blood mononuclear cells and present a detailed comparison of these sNPCs with NPCs obtained from the same blood samples through stable iPSC clones and a subsequent neural differentiation (classical NPCs-cNPCs). Peripheral blood cells were obtained from a schizophrenia patient and his two healthy parents (a case-parent trio), while a further umbilical cord blood sample was obtained from the cord of a healthy new-born. The expression of stage-specific markers in sNPCs and cNPCs were compared both at the protein and RNA levels. We also performed functional tests to investigate Wnt and glutamate signaling and the oxidative stress, as these pathways have been suggested to play important roles in the pathophysiology of schizophrenia. We found similar responses in the two types of NPCs, suggesting that the shortcut procedure provides sNPCs, allowing an efficient screening of disease-related phenotypes.

Nuclear receptor TLX may be through regulating the SIRT1/NF-κB pathway to ameliorate cognitive impairment in chronic cerebral hypoperfusion

BACKGROUND

Chronic cerebral hypoperfusion (CCH) is a common pathophysiological mechanism in neurodegenerative diseases, such as Alzheimer's disease and vascular dementia. The orphan nuclear receptor TLX plays an important role in neural development, adult neurogenesis and cognition. The aim of this study was to investigate the neuroprotective effects of TLX on cognitive dysfunction, hippocampal neurogenesis and neuroinflammation in a rat model of CCH and to assess the possible mechanisms.

METHODS

Permanent bilateral common carotid artery occlusion (2-VO) was used to establish a model of CCH. Stereotaxic injection of an adeno-associated virus vector expressing TLX was used to overexpress TLX in the hippocampus. Cognitive function was evaluated by the Morris Water Maze test. Immunofluorescent staining was used to assess hippocampal neurogenesis. The effects of overexpression of TLX on SIRT1 and inflammatory cytokines were analyzed with qRT-PCR and western blot.

RESULT

After 2-VO, CCH rats exhibited cognitive impairment and reduction of hippocampal TLX levels. Overexpression of TLX ameliorated cognitive impairments with increasing number of BrdU + cells and BrdU + NeuN + cells in DG. Furthermore, TLX rescued the reduced SIRT1 usually induced by CCH. Additionally, TLX also inhibited the expression of inflammatory cytokines such as NF-κB and IL-1β.

CONCLUSIONS

The present findings suggested that TLX exerted protective effects against cognitive deficits induced by CCH. The possible mechanisms of TLX may be through regulating the SIRT1/NF-κB pathway, promoting hippocampal neurogenesis and inhibiting the neuroinflammatory response.

Genetic analysis of the NR2E1 gene as a candidate gene of schizophrenia

NR2E1 is implicated in the regulation of neurogenesis and considered as a candidate gene for schizophrenia. We resequenced all the exons of NR2E1 in 547 patients with schizophrenia and 567 controls from Taiwan. We identified five common SNPs with no association with patients with schizophrenia. Further haplotype-based association analysis showed that two haplotypes within NR2E1 were correlated with the schizophrenia risk. Four rare mutations located at untranslated regions were identified in patients with schizophrenia but not in our control sample. The present study suggests that NR2E1 is likely to play a significant role in conferring susceptibility to schizophrenia.

Loss-of-function Mutations of CUL3, a High Confidence Gene for Psychiatric Disorders, Lead to Aberrant Neurodevelopment In Human Induced Pluripotent Stem Cells

Both rare, high risk, loss-of-function mutations and common, low risk, genetic variants in the CUL3 gene are strongly associated with neuropsychiatric disorders. Network analyses of neuropsychiatric risk genes have shown high CUL3 expression in the prenatal human brain and an enrichment in neural precursor cells (NPCs) and cortical neurons. The role of CUL3 in human neurodevelopment however, is poorly understood. In the present study, we used CRISPR/Cas9 nickase to knockout CUL3 in human induced pluripotent stem cells (iPSCs). iPSCs were subsequently differentiated into cortical glutamatergic neurons using two different protocols and tested for structural/functional alterations. Immunocytochemical analysis and transcriptomic profiling revealed that pluripotency of heterozygous CUL3 knockout (KO) iPSCs remained unchanged compared to isogenic control iPSCs. Following small molecule-mediated differentiation into cortical glutamatergic neurons however, we detected a significant delay in transition from proliferating radial glia cells/NPCs to postmitotic neurons in CUL3 KO cultures. Notably, direct neural conversion of CUL3 KO iPSCs by lentiviral expression of Neurogenin-2 massively attenuated the neurodevelopmental delay. However, both optogenetic and electrical stimulation of induced neurons revealed decreased excitability in Cullin-3 deficient cultures, while basal synaptic transmission remained unchanged. Analysis of target gene expression pointed to alterations in FGF signaling in CUL3 KO NPCs, which is required for NPC proliferation and self-renewal, while RhoA and Notch signaling appeared unaffected. Our data provide first evidence for a major role of Cullin-3 in neuronal differentiation, and for neurodevelopmental deficits underlying neuropsychiatric disorders associated with CUL3 mutations.

MicroRNA-219a-5p-mediated inhibition of CaMKIIγ facilitates vestibular compensation in acute vertigo by promoting protein kinase C expression

Vestibular compensation (VC) refers to a behavioral recovery process in which firing rates of bilateral vestibular nuclei neurons are rebalanced. Our study aimed to investigate the underlying mechanism by which miR-219a-5p regulates Ca²⁺ /calmodulin-dependent protein kinase II γ isoform (CaMKIIγ) and protein kinase C (PKC) in VC. A unilateral vestibular deafferentation rat model was established by unilateral labyrinthectomy (UL), after which VC was evaluated in rats with UL-induced vertigo-like behavior by measuring vestibular defect behavior and performing rotarod tests, as well as by BrdU immunohistochemistry on medial vestibular nuclei. We found that miR-219a-5p was increased while CaMKIIγ was decreased during VC in the medial vestibular nucleus of rats that had undergone UL. Next, gain- and loss-of-function assays were conducted to evaluate the effects of miR-219a-5p and CaMKIIγ on the vestibular defect behaviors and VC, the results of which suggested that in rats after UL overexpression of CaMKIIγ inhibited VC, while overexpression of miR-219a-5p facilitated VC. A dual-luciferase reporter gene assay identified that miR-219a-5p targeted CaMKIIγ. This led to additional experiments showing that miR-219a-5p aptomir expression downregulated CaMKIIγ in cortical cells with a concomitant increase in PKC expression, which were verified further in vivo. In summary, in rats with acute vertigo, miR-219a-5p overexpression inhibits CaMKIIγ and elevates PKC, thereby facilitating VC. Our study offers possible targets for further evaluation as treatment of acute vertigo in humans.

Characterization of miRNAs from sardine (Sardina pilchardus Walbaum, 1792) and their tissue-specific expression analysis in brain and liver

MicroRNAs are endogenous highly conserved short (~ 21 nucleotides) non-coding RNA molecules that play key roles in post-transcriptional gene regulation by translational inhibition or by target mRNA cleavage. In this report, using high stringent computational-based methods, a total of 101 putative miRNAs were identified from European sardine fish (Sardina pilchardus Walbaum, 1792). All the precursors of identified sardine miRNAs formed stable stem-loop structures and displayed high minimum free energy index (MFEI) values. For the experimental validation of the computationally predicted miRNAs, a tissue-specific quantitative study of eight randomly selected putative sardine miRNAs (spi-miR9, spi-miR26, spi-miR128, spi-miR129, spi-miR132, spi-miR212, spi-miR219, and spi-miR338) was performed in brain and liver and all the selected miRNAs were found to be overexpressed in brain tissue. Moreover, using RNAhybrid, a total of 83 potential target proteins of the characterized sardine miRNAs were identified those are involved in transcription, cellular development, defense mechanism, and various signaling pathways. To the best of our knowledge, this is the first report of sardine microRNAs and their targets.

Secretory immunoglobulin A from human milk hydrolyzes microRNA

For breast-fed infants, human milk is a source of various nutrients (e.g., proteins, peptides, antibodies) and bioactive components that promote neonatal growth and protect infants from viral and bacterial infection. Moreover, in terms of infant nutrition and protection the functions of many human milk components are very different from those of blood and other biological fluids of healthy adults. For example, catalytic antibodies ("abzymes") with synthetic activities (protein, oligosaccharide, and lipid kinase activities) have been found in human breast milk that are absent in the blood of healthy people. Abzymes with hydrolyzing functions have been detected not only in milk, but also in the blood of patients with autoimmune diseases. Obviously, feeding newborns human milk has a very specific role and it is a unique aspect of mammalian nutrition. Ribonuclease and DNase autoantibodies or abzymes are found in milk and blood of lactating women, but not in blood sera of healthy men and nonpregnant woman. Here, we present the first evidence that human milk secretory IgA molecules (sIgA) can effectively hydrolyze ribooligonucleotides containing 23 different bases [(pN)₂₃ ribooligonucleotides] and 4 microRNAs: miR-9-5p, miR-219-2-3p, miR-137, and miR-219a-5p. Ribonuclease activity is an inherent property of sIgAs. We showed that 7 individual sIgAs hydrolyzed the ribooligonucleotides (pA)₂₃, (pU)₂₃, and (pC)₂₃ nonspecifically and with comparable efficiency, whereas hydrolysis of the 4 microRNAs by sIgAs was site-specific. Sites of hydrolysis of 4 microRNAs by IgG from blood of patients with schizophrenia have been previously identified. The sites of hydrolysis of 4 microRNAs by sIgA-abzymes were very different from the previously identified sites of hydrolysis by IgG in patients with schizophrenia. In addition, in contrast to IgG, milk sIgAs efficiently hydrolyzed microRNAs in their loop and duplex regions.

Investigation of Schizophrenia with Human Induced Pluripotent Stem Cells

Schizophrenia is a chronic and severe neuropsychiatric condition manifested by cognitive, emotional, affective, perceptual, and behavioral abnormalities. Despite decades of research, the biological substrates driving the signs and symptoms of the disorder remain elusive, thus hampering progress in the development of treatments aimed at disease etiologies. The recent emergence of human induced pluripotent stem cell (hiPSC)-based models has provided the field with a highly innovative approach to generate, study, and manipulate living neural tissue derived from patients, making possible the exploration of fundamental roles of genes and early-life stressors in disease-relevant cell types. Here, we begin with a brief overview of the clinical, epidemiological, and genetic aspects of the condition, with a focus on schizophrenia as a neurodevelopmental disorder. We then highlight relevant technical advancements in hiPSC models and assess novel findings attained using hiPSC-based approaches and their implications for disease biology and treatment innovation. We close with a critical appraisal of the developments necessary for both further expanding knowledge of schizophrenia and the translation of new insights into therapeutic innovations.

IgGs from Human Milk Hydrolyze microRNAs

Mother’s milk provides breast-fed infants with various nutrients, including peptides, proteins, DNA, RNA, antibodies, and other bioactive components promoting neonatal growth and protecting infants from viral and bacterial infection. The functions of many human milk components regarding the nutrition and protection of newborns may be very different compared to those of various biological fluids of healthy adults. For example, human milk contains catalytic antibodies (abzymes) with protein, lipid, and oligosaccharide kinase activities, which are absent in the biological fluids of healthy people and autoimmune patients. Obviously, the nutrition of infants with fresh breast milk is a special phenomenon having a very specific and important role. Here, we have shown that mother’s milk IgGs effectively split homo-(pN)23, and four miRNAs: miR-137, miR-219a-5p, miR-219-2-3p, and miR-9-5p. It was shown that ribonuclease activity is a unique property of milk IgGs. On average, individual IgGs hydrolyze (pA)23, (pU)23, and (pC)23 nonspecifically and with comparable efficiency, whereas the hydrolysis of four miRNAs is predominately site-specific. The specific sites of the hydrolysis of four miRNAs by IgGs from the blood of schizophrenic (SCZ) patients and secretory immunoglobulins A (sIgAs) from human milk were found earlier. The sites of the hydrolysis of four miRNAs by milk IgGs and sIgA-abzymes are almost the same, but are significantly different in comparison with those for SCZ IgGs. In addition, in contrast to the SCZ IgGs, milk IgGs and sIgAs efficiently hydrolyzed miRNAs in the duplex regions formed by their terminal sequences.

Mental health dished up-the use of iPSC models in neuropsychiatric research

Genetic and molecular mechanisms that play a causal role in mental illnesses are challenging to elucidate, particularly as there is a lack of relevant in vitro and in vivo models. However, the advent of induced pluripotent stem cell (iPSC) technology has provided researchers with a novel toolbox. We conducted a systematic review using the PRISMA statement. A PubMed and Web of Science online search was performed (studies published between 2006–2020) using the following search strategy: hiPSC OR iPSC OR iPS OR stem cells AND schizophrenia disorder OR personality disorder OR antisocial personality disorder OR psychopathy OR bipolar disorder OR major depressive disorder OR obsessive compulsive disorder OR anxiety disorder OR substance use disorder OR alcohol use disorder OR nicotine use disorder OR opioid use disorder OR eating disorder OR anorexia nervosa OR attention-deficit/hyperactivity disorder OR gaming disorder. Using the above search criteria, a total of 3515 studies were found. After screening, a final total of 56 studies were deemed eligible for inclusion in our study. Using iPSC technology, psychiatric disease can be studied in the context of a patient’s own unique genetic background. This has allowed great strides to be made into uncovering the etiology of psychiatric disease, as well as providing a unique paradigm for drug testing. However, there is a lack of data for certain psychiatric disorders and several limitations to present iPSC-based studies, leading us to discuss how this field may progress in the next years to increase its utility in the battle to understand psychiatric disease.

Modeling Psychiatric Disorder Biology with Stem Cells

PURPOSE OF REVIEW

We review the ways in which stem cells are used in psychiatric disease research, including the related advances in gene editing and directed cell differentiation.

RECENT FINDINGS

The recent development of induced pluripotent stem cell (iPSC) technologies has created new possibilities for the study of psychiatric disease. iPSCs can be derived from patients or controls and differentiated to an array of neuronal and non-neuronal cell types. Their genomes can be edited as desired, and they can be assessed for a variety of phenotypes. This makes them especially interesting for studying genetic variation, which is particularly useful today now that our knowledge on the genetics of psychiatric disease is quickly expanding. The recent advances in cell engineering have led to powerful new methods for studying psychiatric illness including schizophrenia, bipolar disorder, and autism. There is a wide array of possible applications as illustrated by the many examples from the literature, most of which are cited here.

Deficits in developmental neurogenesis and dendritic spine maturation in mice lacking the serine protease inhibitor neuroserpin

Neuroserpin is a serine protease inhibitor of the nervous system required for normal synaptic plasticity and regulating cognitive, emotional and social behavior in mice. The high expression level of neuroserpin detected at late stages of nervous system formation in most regions of the brain points to a function in neurodevelopment. In order to evaluate the contribution of neuroserpin to brain development, we investigated developmental neurogenesis and neuronal differentiation in the hippocampus of neuroserpin-deficient mice. Moreover, synaptic reorganization and composition of perineuronal net were studied during maturation and stabilization of hippocampal circuits. We showed that absence of neuroserpin results in early termination of neuronal precursor proliferation and premature neuronal differentiation in the first postnatal weeks. Additionally, at the end of the critical period neuroserpin-deficient mice had changed morphology of dendritic spines towards a more mature phenotype. This was accompanied by increased protein levels and reduced proteolytic cleavage of aggrecan, a perineuronal net core protein. These data suggest a role for neuroserpin in coordinating generation and maturation of the hippocampus, which is essential for establishment of an appropriate neuronal network.

Species-Specific miRNAs in Human Brain Development and Disease

Identification of the unique features of human brain development and function can be critical towards the elucidation of intricate processes such as higher cognitive functions and human-specific pathologies like neuropsychiatric and behavioral disorders. The developing primate and human central nervous system (CNS) are distinguished by expanded progenitor zones and a protracted time course of neurogenesis, leading to the expansion in brain size, prominent gyral anatomy, distinctive synaptic properties, and complex neural circuits. Comparative genomic studies have revealed that adaptations of brain capacities may be partly explained by human-specific genetic changes that impact the function of proteins associated with neocortical expansion, synaptic function, and language development. However, the formation of complex gene networks may be most relevant for brain evolution. Indeed, recent studies identified distinct human-specific gene expression patterns across developmental time occurring in brain regions linked to cognition. Interestingly, such modules show species-specific divergence and are enriched in genes associated with neuronal development and synapse formation whilst also being implicated in neuropsychiatric diseases. microRNAs represent a powerful component of gene-regulatory networks by promoting spatiotemporal post-transcriptional control of gene expression in the human and primate brain. It has also been suggested that the divergence in miRNA expression plays an important role in shaping gene expression divergence among species. Primate-specific and human-specific miRNAs are principally involved in progenitor proliferation and neurogenic processes but also associate with human cognition, and neurological disorders. Human embryonic or induced pluripotent stem cells and brain organoids, permitting experimental access to neural cells and differentiation stages that are otherwise difficult or impossible to reach in humans, are an essential means for studying species-specific brain miRNAs. Single-cell sequencing approaches can further decode refined miRNA-mRNA interactions during developmental transitions. Elucidating species-specific miRNA regulation will shed new light into the mechanisms that control spatiotemporal events during human brain development and disease, an important step towards fostering novel, holistic and effective therapeutic approaches for neural disorders. In this review, we discuss species-specific regulation of miRNA function, its contribution to the evolving features of the human brain and in neurological disease, with respect also to future therapeutic approaches.

Extracellular Nanomatrix-Induced Self-Organization of Neural Stem Cells into Miniature Substantia Nigra-Like Structures with Therapeutic Effects on Parkinsonian Rats

Substantia nigra (SN) is a complex and critical region of the brain wherein Parkinson's disease (PD) arises from the degeneration of dopaminergic neurons. Miniature SN-like structures (mini-SNLSs) constructed from novel combination of nanomaterials and cell technologies exhibit promise as potentially curative cell therapies for PD. In this work, a rapid self-organization of mini-SNLS, with an organizational structure and neuronal identities similar to those of the SN in vivo, is achieved by differentiating neural stem cells in vitro on biocompatible silica nanozigzags (NZs) sculptured by glancing angle deposition, without traditional chemical growth factors. The differentiated neurons exhibit electrophysiological activity in vitro. Diverse physical cues and signaling pathways that are determined by the nanomatrices and lead to the self-organization of the mini-SNLSs are clarified and elucidated. In vivo, transplantation of the neurons from a mini-SNLS results in an early and progressive amelioration of PD in rats. The sculptured medical device reported here enables the rapid and specific self-organization of region-specific and functional brain-like structures without an undesirable prognosis. This development provides promising and significant insights into the screening of potentially curative drugs and cell therapies for PD.

GFAP Mutations in Astrocytes Impair Oligodendrocyte Progenitor Proliferation and Myelination in an hiPSC Model of Alexander Disease

Alexander disease (AxD) is a leukodystrophy that primarily affects astrocytes and is caused by mutations in the astrocytic filament gene GFAP. While astrocytes are thought to have important roles in controlling myelination, AxD animal models do not recapitulate critical myelination phenotypes and it is therefore not clear how AxD astrocytes contribute to leukodystrophy. Here, we show that AxD patient iPSC-derived astrocytes recapitulate key features of AxD pathology such as GFAP aggregation. Moreover, AxD astrocytes inhibit proliferation of human iPSC-derived oligodendrocyte progenitor cells (OPCs) in co-culture and reduce their myelination potential. CRISPR/Cas9-based correction of GFAP mutations reversed these phenotypes. Transcriptomic analyses of AxD astrocytes and postmortem brains identified CHI3L1 as a key mediator of AxD astrocyte-induced inhibition of OPC activity. Thus, this iPSC-based model of AxD not only recapitulates patient phenotypes not observed in animal models, but also reveals mechanisms underlying disease pathology and provides a platform for assessing therapeutic interventions.

CRISPR/Cas9-mediated Knockout of the Neuropsychiatric Risk Gene KCTD13 Causes Developmental Deficits in Human Cortical Neurons Derived from Induced Pluripotent Stem Cells

The human KCTD13 gene is located within the 16p11.2 locus and copy number variants of this locus are associated with a high risk for neuropsychiatric diseases including autism spectrum disorder and schizophrenia. Studies in zebrafish point to a role of KCTD13 in proliferation of neural precursor cells which may contribute to macrocephaly in 16p11.2 deletion carriers. KCTD13 is highly expressed in the fetal human brain and in mouse cortical neurons, but its contribution to the development and function of mammalian neurons is not completely understood. In the present study, we deleted the KCTD13 gene in human-induced pluripotent stem cells (iPSCs) using CRISPR/Cas9 nickase. Following neural differentiation of KCTD13 deficient and isogenic control iPSC lines, we detected a moderate but significant inhibition of DNA synthesis and proliferation in KCTD13 deficient human neural precursor cells. KCTD13 deficient cortical neurons derived from iPSCs showed decreased neurite formation and reduced spontaneous network activity. RNA-sequencing and pathway analysis pointed to a role for ERBB signaling in these phenotypic changes. Consistently, activating and inhibiting ERBB kinases rescued and aggravated, respectively, impaired neurite formation. In contrast to findings in non-neuronal human HeLa cells, we did not detect an accumulation of the putative KCTD13/Cullin-3 substrate RhoA, and treatment with inhibitors of RhoA signaling did not rescue decreased neurite formation in human KCTD13 knockout neurons. Taken together, our data provide insight into the role of KCTD13 in neurodevelopmental disorders, and point to ERBB signaling as a potential target for neuropsychiatric disorders associated with KCTD13 deficiency.

Stem cell models of schizophrenia, what have we learned and what is the potential?

Schizophrenia is a complex disorder with clinical manifestations in early adulthood. However, it may start with disruption of brain development caused by genetic or environmental factors, or both. Early deteriorating effects of genetic/environmental factors on neural development might be key to described disease causing mechanisms. Establishing cellular models with cells from affected individual using the induced pluripotent stem cells (iPSC) technology could be used to mimic early neurodevelopment alterations caused by risk genes or environmental stressors. Indeed, cellular models have allowed identification and further study of risk factors and the biological pathways in which they are involved. New advancements in differentiation methods such as defined and robust monolayer protocols and cerebral 3D organoids have made it possible to faithfully mimic neural development and neuronal functionality while CRISPR-editing tools assist to engineer isogenic cell lines to precisely explore genetic variation in polygenic diseases such as schizophrenia. Here we review the current field of iPSC models of schizophrenia and how risk factors can be modelled as well as discussing the common biological pathways involved.

miR-219a-5p Ameliorates Hepatic Ischemia/Reperfusion Injury via Impairing TP53BP2

BACKGROUND

Hepatic ischemia/reperfusion (I/R) injury is a serious complication that occurs upon hypovolemic shock, liver resection, and transplantation. A significant age-dependent difference in the injury response to hepatic I/R in both human and animal models has been reported. Nevertheless, the molecular mechanism is currently unclear.

AIMS

To clarify the reason why aged animals or people were more vulnerable to hepatic I/R injury.

METHODS

In the present study, we found decreased miR-219a-5p expression in the old mice more vulnerable to hepatic I/R injury. Administrated with agomir-miR-219a-5p diminished the severity of hepatic I/R injury in old mice, as indicated by lower serum ALT and AST, oxidative parameters including MDA, TOA, and OSI, and decreased apoptotic cell number. The effect of miR-219a-5p was also confirmed in the H₂O₂-induced apoptosis model in AML-12 and NCTC1469 cells. After miR-219a-5p overexpression, two key apoptosis-related proteins Bax and P21, target genes of TP53, were decreased. Furthermore, TP53BP2 interacts with p53 family members and promotes their transcriptional activities toward pro-apoptosis genes.

RESULTS

RNA sequencing, western blot, and luciferase reporter assay proved that TP53BP2, a crucial TP53 transcriptional activity enhancer in vivo, was directly regulated by miR-219a-5p.

CONCLUSIONS

In summary, our study demonstrated that age-related miR-219a-5p can attenuate hepatic I/R injury through inhibiting TP53BP2 and downstream TP53-dependent apoptosis of hepatic cells in mice.

MLS128 antibody-induced suppression of colon cancer cell growth is mediated by a desmocollin and a 110 kDa glycoprotein

Protein glycosylation is a diverse form of post-translational modification. Two to three consecutive O-linked N-acetylgalactosamines (Tn-antigens) are recognized by antibodies such as MLS128. MLS128 mAb inhibited cell growth and bound to a 110 kDa glycoprotein (GP) in LS180 and HT29 colon cancer cells. However, purification and identification of the 110 kDa GP was unsuccessful due to its low abundance. The present study used a highly sophisticated and sensitive mass spectrometry method to identify proteins immunoprecipitated with MLS128 and separated by two-dimensional gel electrophoresis. Three desmosome components were identified. Of these, desmocollin and desmoglein shared many similar characteristics, including molecular mass, pI, and potential Tn-antigen sites. Western blotting analyses of LS180 cell lysates revealed a common 110 kDa band recognized by MLS128 and anti-desmocollin, but not by anti-desmoglein. Immunofluorescence microscopy of LS180 cells revealed that desmocollin is membrane-bound, while desmoglein is primarily localized in the cytosol. Confocal microscopy demonstrated colocalization of the desmocollin-specific antibody with the MLS128 antibody on the cell membrane, suggesting that desmocollin may contain Tn-antigens recognized by MLS128. Treatment of LS180 cells with siRNA to knock down desmocollin expression or a desmocollin-specific antibody decreased cell viability, suggesting a critical role for this protein in cell growth and survival. N-glycosidase F digestion of the 110 kDa GP and desmocollin suggested that although both proteins contain N-glycosylation sites, they are not identical. These findings suggest that desmocollin colocalizes with the 110 kDa GP and that growth inhibition induced by the MLS128 antibody may be mediated through a mechanism that involves desmocollin.

Screening the expression of several miRNAs from TaqMan Low Density Array in traumatic brain injury: miR-219a-5p regulates neuronal apoptosis by modulating CCNA2 and CACUL1

Circulating microRNAs (miRNAs) have emerged as diagnostic and prognostic biomarkers for traumatic brain injury (TBI). However, a comprehensive characterization of the serum miRNA profile in patients with TBI and the roles of these potential markers in neuronal regulation have rarely been reported. In this study, the levels of 754 serum miRNAs were initially determined in two pooled samples of 15 severe traumatic brain injury (sTBI) patients and 15 healthy controls using a TaqMan Low Density Array. The markedly upregulated miRNAs in sTBI patients were subsequently validated individually by quantitative reverse-transcription PCR (RT-qPCR) in another larger cohort consisting of 81 sTBI patients, 81 mild traumatic brain injury (mTBI) patients and 82 age/sex-matched healthy controls. Seven miRNAs, including miR-103a-3p, miR-219a-5p, miR-302d-3p, miR-422a, miR-518f-3p, miR-520d-3p and miR-627, were significantly upregulated in both sTBI and mTBI patients compared with their expression in controls. Among these miRNAs, miR-219a-5p not only discriminated sTBI and mTBI patients from controls but also discriminated between sTBI and mTBI patients. We further show here that in the neuronal cell injury model, upregulated miR-219a-5p inhibits the expression of CCNA2 and CACUL1 and further regulates akt/Foxo3a and p53/Bcl-2 signaling pathways, causing a notable change in the expression of cleaved caspase-3, thereby inducing neuronal apoptosis. These results indicate that these seven selected miRNAs could serve as novel biomarkers for TBI. In particular, miR-219a-5p is a potentially valuable indicator of the diagnosis, prognosis of TBI and appears to regulate neuronal apoptosis and death.