Pluripotent stem cell-derived neural progenitor cells can be used to model effects of IL-6 on human neurodevelopment.

Maternal immune activation (MIA) increases the risks for neurodevelopmental disorders in offspring through inflammatory cytokines, including interleukin-6 (IL-6). We therefore aimed to establish a human two-dimensional (2D) in vitro neural model to investigate the effects of IL-6 exposure on neurodevelopment. IL-6 signal transduction requires two receptors: interleukin-6 signal transducer (IL6ST) and interleukin-6 receptor (IL6R). Prenatally, neural cells lack IL6R, and hence cannot elicit cis IL-6 signaling, but IL6R can be provided by microglia in trans. We demonstrate here that an immortalized human neural progenitor cell (NPC) line, ReNCell CX, expresses IL6ST and elicits both cis and trans IL-6 signaling, limiting its use as a model of MIA. In contrast, induced pluripotent stem cell (iPSC)-derived NPCs only activate the IL-6 cascade in trans. Activation of the trans IL-6 cascade did not result in increased proliferation of iPSC-derived NPCs or ReNCell CX, as has been demonstrated in animal models. iPSC-derived NPCs upregulated NR2F1 expression in response to IL-6 signaling in line with analogous experiments in organoids. Thus, iPSC-derived NPCs can be used to model gene expression changes in response to MIA in 2D cultures.

Single-cell analysis of prenatal and postnatal human cortical development.

We analyzed >700,000 single-nucleus RNA sequencing profiles from 106 donors during prenatal and postnatal developmental stages and identified lineage-specific programs that underlie the development of specific subtypes of excitatory cortical neurons, interneurons, glial cell types, and brain vasculature. By leveraging single-nucleus chromatin accessibility data, we delineated enhancer gene regulatory networks and transcription factors that control commitment of specific cortical lineages. By intersecting our results with genetic risk factors for human brain diseases, we identified the cortical cell types and lineages most vulnerable to genetic insults of different brain disorders, especially autism. We find that lineage-specific gene expression programs up-regulated in female cells are especially enriched for the genetic risk factors of autism. Our study captures the molecular progression of cortical lineages across human development.

The RCX Extension Hub: A Resource for Implementations Extending the R Adaption of the Cytoscape Exchange Format.

Public repositories provide access to biological networks for investigations, and subsequently serve to distribute the network encoded biomedical and even clinically relevant results. However, inclusion of complementary information requires data structures and implementations customized to the integrated data for network representation, usage in supporting application, and extending analysis functionality. Partitioning of this information into individual aspects of a network facilitates compatibility and reusability of the network-based results, but also requires support and accessibility of the extensions and their implementations. The RCX extension hub offers overview and access to extensions of the Cytoscape exchange format implemented in R. The hub supports the realization of self-customized extension through guides, example implementations, and a template for the creation of R extension packages.

Human brain organoid model of maternal immune activation identifies radial glia cells as selectively vulnerable.

Maternal immune activation (MIA) during critical windows of gestation is correlated with long-term neurodevelopmental deficits in the offspring, including increased risk for autism spectrum disorder (ASD) in humans. Interleukin 6 (IL-6) derived from the gestational parent is one of the major molecular mediators by which MIA alters the developing brain. In this study, we establish a human three-dimensional (3D) in vitro model of MIA by treating induced pluripotent stem cell-derived dorsal forebrain organoids with a constitutively active form of IL-6, Hyper-IL-6. We validate our model by showing that dorsal forebrain organoids express the molecular machinery necessary for responding to Hyper-IL-6 and activate STAT signaling upon Hyper-IL-6 treatment. RNA sequencing analysis reveals the upregulation of major histocompatibility complex class I (MHCI) genes in response to Hyper-IL-6 exposure, which have been implicated with ASD. We find a small increase in the proportion of radial glia cells after Hyper-IL-6 treatment through immunohistochemistry and single-cell RNA-sequencing. We further show that radial glia cells are the cell type with the highest number of differentially expressed genes, and Hyper-IL-6 treatment leads to the downregulation of genes related to protein translation in line with a mouse model of MIA. Additionally, we identify differentially expressed genes not found in mouse models of MIA, which might drive species-specific responses to MIA. Finally, we show abnormal cortical layering as a long-term consequence of Hyper-IL-6 treatment. In summary, we establish a human 3D model of MIA, which can be used to study the cellular and molecular mechanisms underlying the increased risk for developing disorders such as ASD.

Data-dependent visualization of biological networks in the web-browser with NDExEdit.

Networks are a common methodology used to capture increasingly complex associations between biological entities. They serve as a resource of biological knowledge for bioinformatics analyses, and also comprise the subsequent results. However, the interpretation of biological networks is challenging and requires suitable visualizations dependent on the contained information. The most prominent software in the field for the visualization of biological networks is Cytoscape, a desktop modeling environment also including many features for analysis. A further challenge when working with networks is their distribution. Within a typical collaborative workflow, even slight changes of the network data force one to repeat the visualization step as well. Also, just minor adjustments to the visual representation not only need the networks to be transferred back and forth. Collaboration on the same resources requires specific infrastructure to avoid redundancies, or worse, the corruption of the data. A well-established solution is provided by the NDEx platform where users can upload a network, share it with selected colleagues or make it publicly available. NDExEdit is a web-based application where simple changes can be made to biological networks within the browser, and which does not require installation. With our tool, plain networks can be enhanced easily for further usage in presentations and publications. Since the network data is only stored locally within the web browser, users can edit their private networks without concerns of unintentional publication. The web tool is designed to conform to the Cytoscape Exchange (CX) format as a data model, which is used for the data transmission by both tools, Cytoscape and NDEx. Therefore the modified network can be directly exported to the NDEx platform or saved as a compatible CX file, additionally to standard image formats like PNG and JPEG.

The Effects of Environmental Adversities on Human Neocortical Neurogenesis Modeled in Brain Organoids.

Over the past decades, a growing body of evidence has demonstrated the impact of prenatal environmental adversity on the development of the human embryonic and fetal brain. Prenatal environmental adversity includes infectious agents, medication, and substances of use as well as inherently maternal factors, such as diabetes and stress. These adversities may cause long-lasting effects if occurring in sensitive time windows and, therefore, have high clinical relevance. However, our knowledge of their influence on specific cellular and molecular processes of in utero brain development remains scarce. This gap of knowledge can be partially explained by the restricted experimental access to the human embryonic and fetal brain and limited recapitulation of human-specific neurodevelopmental events in model organisms. In the past years, novel 3D human stem cell-based in vitro modeling systems, so-called brain organoids, have proven their applicability for modeling early events of human brain development in health and disease. Since their emergence, brain organoids have been successfully employed to study molecular mechanisms of Zika and Herpes simplex virus-associated microcephaly, as well as more subtle events happening upon maternal alcohol and nicotine consumption. These studies converge on pathological mechanisms targeting neural stem cells. In this review, we discuss how brain organoids have recently revealed commonalities and differences in the effects of environmental adversities on human neurogenesis. We highlight both the breakthroughs in understanding the molecular consequences of environmental exposures achieved using organoids as well as the on-going challenges in the field related to variability in protocols and a lack of benchmarking, which make cross-study comparisons difficult.

Hope and Distress Are Not Associated With the Brain Tumor Stage.

OBJECTIVE: Hopelessness and depression are strongly associated with suicidality. Given that physical and psychological outcomes can be altered with hope, hope is a therapeutic goal of increasing importance in the treatment of brain tumor patients. Moreover, it is not yet understood which factors affect the perception of hope in brain tumor patients. In addition, it remains uncertain whether lower-grade brain tumor patients suffer less from psycho-oncological distress than higher-grade brain tumor patients. METHODS: Neuro-oncological patients were examined perioperatively with the Distress Thermometer (DT) and the Herth Hope Index (HHI). In addition, psychological comorbidities (anxiety GAD-2, depression PHQ-2) and an assessment of general psycho-oncological distress were recorded. RESULTS: Sixty-six brain tumor patients were included (median age 53 years, 35% higher-grade brain tumors, i.e., WHO grade III/IV). No differences between higher- and lower-grade brain tumor patients were observed for general psycho-oncological distress and hope. However, higher-grade brain tumor patients showed a significantly higher level of depression (p ≤ 0.001) and more negative expectations regarding therapeutic success (H = 4.873, p ≤ 0.050). The extent of depression correlated negatively with hope. CONCLUSION: Unexpectedly, higher-grade brain tumor patients remained as hopeful as lower-grade brain tumor patients despite the devastating diagnosis, higher levels of depression, and a worse expectation of therapeutic success. Conversely, lower-grade brain tumor patients experience as much psycho-oncological distress as patients with a higher-grade brain tumor, underpinning the imperative need for comprehensive psycho-oncological screening. For all brain tumor patients, considering hope is important to avoid suicides resulting from hopelessness and depression.

Human organoids to model the developing human neocortex in health and disease.

Rodent models have catalyzed major discoveries in the neocortex, a brain region unique to mammals. However, since the neocortex has expanded considerably in primates, employing rodent models has limitations. Human fetal brain tissue is a scarce resource with limitations for experimental manipulations. In order to create an experimentally tractable representation of human brain development, a number of labs have recently created in vitro models of the developing human brain. These models, generated using human embryonic stem cells or induced pluripotent stem cells, are called "organoids". Organoids have successfully and rapidly uncovered new mechanisms of human brain development in health and disease. In the future, we envision that this strategy will enable faster and more efficient translation of basic neuroscience findings to therapeutic applications. In this review, we discuss the generation of the first human cerebral organoids, progress since their debut, and challenges to be overcome in the future.

A GTPase-induced switch in phospholipid affinity of collybistin contributes to synaptic gephyrin clustering.

Synaptic transmission between neurons relies on the exact spatial organization of postsynaptic transmitter receptors, which are recruited and positioned by dedicated scaffolding and regulatory proteins. At GABAergic synapses, the regulatory protein collybistin (Cb, also known as ARHGEF9) interacts with small GTPases, cell adhesion proteins and phosphoinositides to recruit the scaffolding protein gephyrin and GABAA receptors to nascent synapses. We dissected the interaction of Cb with the small Rho-like GTPase TC10 (also known as RhoQ) and phospholipids. Our data define a protein-lipid interaction network that controls the clustering of gephyrin at synapses. Within this network, TC10 and monophosphorylated phosphoinositides, particulary phosphatidylinositol 3-phosphate (PI3P), provide a coincidence detection platform that allows the accumulation and activation of Cb in endomembranes. Upon activation, TC10 induces a phospholipid affinity switch in Cb, which allows Cb to specifically interact with phosphoinositide species present at the plasma membrane. We propose that this GTPase-based regulatory switch mechanism represents an important step in the process of tethering of Cb-dependent scaffolds and receptors at nascent postsynapses.

Neuronal vulnerability and multilineage diversity in multiple sclerosis.

Multiple sclerosis (MS) is a neuroinflammatory disease with a relapsing-remitting disease course at early stages, distinct lesion characteristics in cortical grey versus subcortical white matter and neurodegeneration at chronic stages. Here we used single-nucleus RNA sequencing to assess changes in expression in multiple cell lineages in MS lesions and validated the results using multiplex in situ hybridization. We found selective vulnerability and loss of excitatory CUX2-expressing projection neurons in upper-cortical layers underlying meningeal inflammation; such MS neuron populations exhibited upregulation of stress pathway genes and long non-coding RNAs. Signatures of stressed oligodendrocytes, reactive astrocytes and activated microglia mapped most strongly to the rim of MS plaques. Notably, single-nucleus RNA sequencing identified phagocytosing microglia and/or macrophages by their ingestion and perinuclear import of myelin transcripts, confirmed by functional mouse and human culture assays. Our findings indicate lineage- and region-specific transcriptomic changes associated with selective cortical neuron damage and glial activation contributing to progression of MS lesions.

Human gestational N-methyl-d-aspartate receptor autoantibodies impair neonatal murine brain function.

OBJECTIVE: Maternal autoantibodies are a risk factor for impaired brain development in offspring. Antibodies (ABs) against the NR1 (GluN1) subunit of the N-methyl-d-aspartate receptor (NMDAR) are among the most frequently diagnosed anti-neuronal surface ABs, yet little is known about effects on fetal development during pregnancy. METHODS: We established a murine model of in utero exposure to human recombinant NR1 and isotype-matched nonreactive control ABs. Pregnant C57BL/6J mice were intraperitoneally injected on embryonic days 13 and 17 each with 240µg of human monoclonal ABs. Offspring were investigated for acute and chronic effects on NMDAR function, brain development, and behavior. RESULTS: Transferred NR1 ABs enriched in the fetus and bound to synaptic structures in the fetal brain. Density of NMDAR was considerably reduced (up to -49.2%) and electrophysiological properties were altered, reflected by decreased amplitudes of spontaneous excitatory postsynaptic currents in young neonates (-34.4%). NR1 AB-treated animals displayed increased early postnatal mortality (+27.2%), impaired neurodevelopmental reflexes, altered blood pH, and reduced bodyweight. During adolescence and adulthood, animals showed hyperactivity (+27.8% median activity over 14 days), lower anxiety, and impaired sensorimotor gating. NR1 ABs caused long-lasting neuropathological effects also in aged mice (10 months), such as reduced volumes of cerebellum, midbrain, and brainstem. INTERPRETATION: The data collectively support a model in which asymptomatic mothers can harbor low-level pathogenic human NR1 ABs that are diaplacentally transferred, causing neurotoxic effects on neonatal development. Thus, AB-mediated network changes may represent a potentially treatable neurodevelopmental congenital brain disorder contributing to lifelong neuropsychiatric morbidity in affected children. ANN NEUROL 2019;86:656-670.

Immature excitatory neurons develop during adolescence in the human amygdala.

The human amygdala grows during childhood, and its abnormal development is linked to mood disorders. The primate amygdala contains a large population of immature neurons in the paralaminar nuclei (PL), suggesting protracted development and possibly neurogenesis. Here we studied human PL development from embryonic stages to adulthood. The PL develops next to the caudal ganglionic eminence, which generates inhibitory interneurons, yet most PL neurons express excitatory markers. In children, most PL cells are immature (DCX+PSA-NCAM+), and during adolescence many transition into mature (TBR1+VGLUT2+) neurons. Immature PL neurons persist into old age, yet local progenitor proliferation sharply decreases in infants. Using single nuclei RNA sequencing, we identify the transcriptional profile of immature excitatory neurons in the human amygdala between 4-15 years. We conclude that the human PL contains excitatory neurons that remain immature for decades, a possible substrate for persistent plasticity at the interface of the hippocampus and amygdala.

Single-cell genomics identifies cell type-specific molecular changes in autism.

Despite the clinical and genetic heterogeneity of autism, bulk gene expression studies show that changes in the neocortex of autism patients converge on common genes and pathways. However, direct assessment of specific cell types in the brain affected by autism has not been feasible until recently. We used single-nucleus RNA sequencing of cortical tissue from patients with autism to identify autism-associated transcriptomic changes in specific cell types. We found that synaptic signaling of upper-layer excitatory neurons and the molecular state of microglia are preferentially affected in autism. Moreover, our results show that dysregulation of specific groups of genes in cortico-cortical projection neurons correlates with clinical severity of autism. These findings suggest that molecular changes in upper-layer cortical circuits are linked to behavioral manifestations of autism.

Multimodal Single-Cell Analysis Reveals Physiological Maturation in the Developing Human Neocortex.

In the developing human neocortex, progenitor cells generate diverse cell types prenatally. Progenitor cells and newborn neurons respond to signaling cues, including neurotransmitters. While single-cell RNA sequencing has revealed cellular diversity, physiological heterogeneity has yet to be mapped onto these developing and diverse cell types. By combining measurements of intracellular Ca2+ elevations in response to neurotransmitter receptor agonists and RNA sequencing of the same single cells, we show that Ca2+ responses are cell-type-specific and change dynamically with lineage progression. Physiological response properties predict molecular cell identity and additionally reveal diversity not captured by single-cell transcriptomics. We find that the serotonin receptor HTR2A selectively activates radial glia cells in the developing human, but not mouse, neocortex, and inhibiting HTR2A receptors in human radial glia disrupts the radial glial scaffold. We show highly specific neurotransmitter signaling during neurogenesis in the developing human neocortex and highlight evolutionarily divergent mechanisms of physiological signaling.

Early Parkinson's Disease Detection via Touchscreen Typing Analysis using Convolutional Neural Networks.

Parkinson's Disease (PD) is the second most common neurodegenerative disorder worldwide, causing both motor and non-motor symptoms. In the early stages, symptoms are mild and patients may ignore their existence. As a result, they do not undergo any related clinical examination; hence delaying their PD diagnosis. In an effort to remedy such delay, analysis of data passively captured from user's interaction with consumer technologies has been recently explored towards remote screening of early PD motor signs. In the current study, a smartphone-based method analyzing subjects' finger interaction with the smartphone screen is developed for the quantification of fine-motor skills decline in early PD using Convolutional Neural Networks. Experimental results from the analysis of keystroke typing in-the-clinic data from 18 early PD patients and 15 healthy controls have shown a classification performance of 0.89 Area Under the Curve (AUC) with 0.79/0.79 sensitivity/specificity, respectively. Evaluation of the generalization ability of the proposed approach was made by its application on typing data arising from a separate self-reported cohort of 27 PD patients' and 84 healthy controls' daily usage with their personal smartphones (data in-the-wild), achieving 0.79 AUC with 0.74/0.78 sensitivity/specificity, respectively. The results show the potentiality of the proposed approach to process keystroke dynamics arising from users' natural typing activity to detect PD, which contributes to the development of digital tools for remote pathological symptom screening.

Human hippocampal neurogenesis drops sharply in children to undetectable levels in adults.

New neurons continue to be generated in the subgranular zone of the dentate gyrus of the adult mammalian hippocampus. This process has been linked to learning and memory, stress and exercise, and is thought to be altered in neurological disease. In humans, some studies have suggested that hundreds of new neurons are added to the adult dentate gyrus every day, whereas other studies find many fewer putative new neurons. Despite these discrepancies, it is generally believed that the adult human hippocampus continues to generate new neurons. Here we show that a defined population of progenitor cells does not coalesce in the subgranular zone during human fetal or postnatal development. We also find that the number of proliferating progenitors and young neurons in the dentate gyrus declines sharply during the first year of life and only a few isolated young neurons are observed by 7 and 13 years of age. In adult patients with epilepsy and healthy adults (18-77 years; n = 17 post-mortem samples from controls; n = 12 surgical resection samples from patients with epilepsy), young neurons were not detected in the dentate gyrus. In the monkey (Macaca mulatta) hippocampus, proliferation of neurons in the subgranular zone was found in early postnatal life, but this diminished during juvenile development as neurogenesis decreased. We conclude that recruitment of young neurons to the primate hippocampus decreases rapidly during the first years of life, and that neurogenesis in the dentate gyrus does not continue, or is extremely rare, in adult humans. The early decline in hippocampal neurogenesis raises questions about how the function of the dentate gyrus differs between humans and other species in which adult hippocampal neurogenesis is preserved.

The need for psycho-oncological support for melanoma patients: Central role of patients' self-evaluation.

Despite an increasing number of promising treatment options, only a limited number of studies concerning melanoma patients' psycho-oncological distress have been carried out. However, multiple screening tools are in use to assess the need for psycho-oncological support. This study aimed first to identify parameters in melanoma patients that are associated with a higher risk for being psycho-oncologically distressed and second to compare patients' self-evaluation concerning the need for psycho-oncological support with the results of established screening tools.We performed a cross-sectional study including 254 melanoma patients from the Center for Dermatooncology at the University of Tuebingen. The study was performed between June 2010 and February 2013. Several screening instruments were included: the Distress Thermometer (DT), Hospital Anxiety and Depression Scale and the patients' subjective evaluation concerning psycho-oncological support. Binary logistic regression was performed to identify factors that indicate the need for psycho-oncological support.Patients' subjective evaluation concerning the need for psycho-oncological support, female gender, and psychotherapeutic or psychiatric treatment at present or in the past had the highest impact on values above threshold in the DT. The odds ratio of patients' self-evaluation (9.89) was even higher than somatic factors like female gender (1.85), duration of illness (0.99), or increasing age (0.97). Patients' self-evaluation concerning the need for psycho-oncological support indicated a moderate correlation with the results of the screening tools included.In addition to the results obtained by screening tools like the DT, we could demonstrate that patients' self-evaluation is an important instrument to identify patients who need psycho-oncological support.

Collybistin activation by GTP-TC10 enhances postsynaptic gephyrin clustering and hippocampal GABAergic neurotransmission.

In many brain regions, gephyrin and GABAA receptor clustering at developing inhibitory synapses depends on the guanine nucleotide exchange factor collybistin (Cb). The vast majority of Cb splice variants contain an autoinhibitory src homology 3 domain, and several synaptic proteins are known to bind to this SH3 domain and to thereby activate gephyrin clustering. However, many functional GABAergic synapses form independently of the known Cb-activating proteins, indicating that additional Cb activators must exist. Here we show that the small Rho-like GTPase TC10 stimulates Cb-dependent gephyrin clustering by binding in its active, GTP-bound state to the pleckstrin homology domain of Cb. Overexpression of a constitutively active TC10 variant in neurons causes an increase in the density of synaptic gephyrin clusters and mean miniature inhibitory postsynaptic current amplitudes, whereas a dominant negative TC10 variant has opposite effects. The enhancement of Cb-induced gephyrin clustering by GTP-TC10 does not depend on the guanine nucleotide exchange activity of Cb but involves an interaction that resembles reported interactions of other small GTPases with their effectors. Our data indicate that GTP-TC10 activates the major src homology 3 domain-containing Cb variants by relieving autoinhibition and thus define an alternative GTPase-driven signaling pathway in the genesis of inhibitory synapses.