TP53-PTEN-NF1 depletion in human brain organoids produces a glioma phenotype in vitro.

Glioblastoma (GBM) is fatal and the study of therapeutic resistance, disease progression, and drug discovery in GBM or glioma stem cells is often hindered by limited resources. This limitation slows down progress in both drug discovery and patient survival. Here we present a genetically engineered human cerebral organoid model with a cancer-like phenotype that could provide a basis for GBM-like models. Specifically, we engineered a doxycycline-inducible vector encoding shRNAs enabling depletion of the TP53, PTEN, and NF1 tumor suppressors in human cerebral organoids. Designated as inducible short hairpin-TP53-PTEN-NF1 (ish-TPN), doxycycline treatment resulted in human cancer-like cerebral organoids that effaced the entire organoid cytoarchitecture, while uninduced ish-TPN cerebral organoids recapitulated the normal cytoarchitecture of the brain. Transcriptomic analysis revealed a proneural GBM subtype. This proof-of-concept study offers a valuable resource for directly investigating the emergence and progression of gliomas within the context of specific genetic alterations in normal cerebral organoids.

Characterization of neural mechanotransduction response in human traumatic brain injury organoid model.

The ability to model physiological systems through 3D neural in-vitro systems may enable new treatments for various diseases while lowering the need for challenging animal and human testing. Creating such an environment, and even more impactful, one that mimics human brain tissue under mechanical stimulation, would be extremely useful to study a range of human-specific biological processes and conditions related to brain trauma. One approach is to use human cerebral organoids (hCOs) in-vitro models. hCOs recreate key cytoarchitectural features of the human brain, distinguishing themselves from more traditional 2D cultures and organ-on-a-chip models, as well as in-vivo animal models. Here, we propose a novel approach to emulate mild and moderate traumatic brain injury (TBI) using hCOs that undergo strain rates indicative of TBI. We subjected the hCOs to mild (2 s[Formula: see text]) and moderate (14 s[Formula: see text]) loading conditions, examined the mechanotransduction response, and investigated downstream genomic effects and regulatory pathways. The revealed pathways of note were cell death and metabolic and biosynthetic pathways implicating genes such as CARD9, ENO1, and FOXP3, respectively. Additionally, we show a steeper ascent in calcium signaling as we imposed higher loading conditions on the organoids. The elucidation of neural response to mechanical stimulation in reliable human cerebral organoid models gives insights into a better understanding of TBI in humans.

The Subventricular Zone in Glioblastoma: Genesis, Maintenance, and Modeling.

Glioblastoma (GBM) is a malignant tumor with a median survival rate of 15-16 months with standard care; however, cases of successful treatment offer hope that an enhanced understanding of the pathology will improve the prognosis. The cell of origin in GBM remains controversial. Recent evidence has implicated stem cells as cells of origin in many cancers. Neural stem/precursor cells (NSCs) are being evaluated as potential initiators of GBM tumorigenesis. The NSCs in the subventricular zone (SVZ) have demonstrated similar molecular profiles and share several distinctive characteristics to proliferative glioblastoma stem cells (GSCs) in GBM. Genomic and proteomic studies comparing the SVZ and GBM support the hypothesis that the tumor cells and SVZ cells are related. Animal models corroborate this connection, demonstrating migratory patterns from the SVZ to the tumor. Along with laboratory and animal research, clinical studies have demonstrated improved progression-free survival in patients with GBM after radiation to the ipsilateral SVZ. Additionally, key genetic mutations in GBM for the most part carry regulatory roles in the SVZ as well. An exciting avenue towards SVZ modeling and determining its role in gliomagenesis in the human context is human brain organoids. Here we comprehensively discuss and review the role of the SVZ in GBM genesis, maintenance, and modeling.

The Evolving Role of Induced Pluripotent Stem Cells and Cerebral Organoids in Treating and Modeling Neurosurgical Diseases.

Over the past decade, the use of induced pluripotent stem cells (IPSCs), as both direct therapeutics and building blocks for 3D in vitro models, has exhibited exciting potential in both helping to elucidate pathogenic mechanisms and treating diseases relevant to neurosurgery. Transplantation of IPSCs is being studied in neurological injuries and diseases, such as spinal cord injury and Parkinson's disease, whose clinical manifestations stem from underlying neuronal and/or axonal degeneration. Both animal models and clinical trials have shown that IPSCs have the ability to regenerate damaged neural tissue. Such evidence makes IPSCs a potentially promising therapeutic modality for patients who suffer from these neurological injuries/diseases. In addition, the cerebral organoid, a 3D assembly of IPSC aggregates that develops heterogeneous brain regions, has become the first in vitro model to closely recapitulate the complexity of the brain extracellular matrix, a 3-dimensional network of molecules that structurally and biochemically support neighboring cells. Cerebral organoids have become an exciting prospect for modeling and testing drug susceptibility of brain tumors, such as glioblastoma and metastatic brain cancer. As patient-derived organoid models are becoming more faithful to the brain, they are becoming an increasingly accurate substitute for patient clinical trials; such patient-less trials would protect the patient from potentially ineffective drugs, and speed up trial results and optimize cost. In this review, we aim to describe the role of IPSCs and cerebral organoids in treating and modeling diseases that are relevant to neurosurgery.

A contemporary update on glioblastoma: molecular biology, current management, and a vision towards bio-adaptable personalized care.

INTRODUCTION: Glioblastoma (GBM) is the most fatal brain tumor in adults. Current survival rates of GBM remain below 2 years due to GBM's aggressive cellular migration and genetically driven treatment escape pathways. Despite our rapidly increasing understanding of GBM biology, earlier diagnoses, and refined surgical techniques, only moderate survival benefits have been achieved. Nonetheless, the pressing need for better survival rates has brought forward a multitude of newer therapeutic approaches and opened the door for potential personalization of these modalities in the near future. METHODS: We reviewed the published literature discussing the current state of knowledge regarding GBM biology and therapy and summarized the information that may point toward future personalized therapeutic strategies. RESULTS: Several novel modalities such as oncolytic viruses, targeted immune, and molecular therapies, and tumor treating fields have been introduced. To date, there is no single treatment modality for GBM, but rather a wide spectrum of combined modalities that address intratumoral cellular and genetic variabilities. While the current state of GBM research and clinical trial landscape may hold promise, current literature lacks any fruitful progress towards personalized GBM therapy. CONCLUSION: In this review, we are discussing our recent knowledge of the GBM genetic biologic landscape and the current advances in therapy, as well as providing a blueprint for an envisioned GBM management paradigm that should be personalized and adaptable to accommodate each patient's diverse genetic variations and therapy response/escape patterns.

Age dependent association of inbreeding with risk for schizophrenia in Egypt.

BACKGROUND: Self-reported consanguinity is associated with risk for schizophrenia (SZ) in several inbred populations, but estimates using DNA-based coefficients of inbreeding are unavailable. Further, it is not known whether recessively inherited risk mutations can be identified through homozygosity by descent (HBD) mapping. METHODS: We studied self-reported and DNA-based estimates of inbreeding among Egyptian patients with SZ (n = 421, DSM IV criteria) and adult controls without psychosis (n = 301), who were evaluated using semi-structured diagnostic interview schedules and genotyped using the Illumina Infinium PsychArray. Following quality control checks, coefficients of inbreeding (F) and regions of homozygosity (ROH) were estimated using PLINK software for HBD analysis. Exome sequencing was conducted in selected cases. RESULTS: Inbreeding was associated with schizophrenia based on self-reported consanguinity (χ2 = 4.506, 1 df, p = 0.034) and DNA-based estimates for inbreeding (F); the latter with a significant F × age interaction (ß = 32.34, p = 0.0047). The association was most notable among patients older than age 40 years. Eleven ROH were over-represented in cases on chromosomes 1, 3, 6, 11, and 14; all but one region is novel for schizophrenia risk. Exome sequencing identified six recessively-acting genes in ROH with loss-of-function variants; one of which causes primary hereditary microcephaly. CONCLUSIONS: We propose consanguinity as an age-dependent risk factor for SZ in Egypt. HBD mapping is feasible for SZ in adequately powered samples.

Using optimal combined moderators to define heterogeneity in neural responses to randomized conditions: Application to the effect of sleep loss on fear learning.

Comparing the neural outcomes of two randomized experimental groups is a primary aim of many functional neuroimaging studies. However, between-group effects can be obscured by heterogeneity in neural responses. Optimal Combined Moderator (OCM) approaches have previously been used to clarify heterogeneity in clinical outcomes following treatment randomization. We show that OCMs can also be used to clarify heterogeneity in the effect of a randomized experimental condition on neural responses. In 78 healthy adults aged 18-30 from the Effects of Dose-Dependent Sleep Disruption on Fear and Reward (SFeRe) study, we used demographic, clinical, genetic, and polysomnographic characteristics to develop OCMs for the effect of a randomized sleep restriction (SR) versus normal sleep (NS) condition on blood-oxygen-level dependent responses in the right amygdala (RAmyg) and subgenual anterior cingulate cortex (sgACC) during fear conditioning (FC) and extinction (FE) paradigms. The OCM for the RAmyg during FE was strongest [r (95% CI) = 0.52 (0.42, 0.68)], withstood cross-validation, and divided the sample into two subgroups with opposing experimental effects. Among N = 48 participants ("SR < NS"), those with SR exhibited less RAmyg activation during FE than those with NS [d (95%CI) = -1.10 (-1.86, -0.77)]. Among the remaining N = 30 participants ("SR > NS"), those with SR exhibited greater RAmyg activation during FE following SR than those with NS [d (95%CI) = 0.87 (0.37,1.78)]. SR > NS participants were more likely to be female, white, l/l genotype carriers, and have a psychiatric history. They had less sleep (overall and in REM), lower REM density, and lower spindle activity (12-16 Hz). Applying OCMs to randomized studies with neural outcomes can clarify neural heterogeneity and jumpstart mechanistic research; with further validation they also offer promise for personalized brain-based treatments and interventions.

Cocaine abuse in humans is not associated with increased microglial activation: an 18-kDa translocator protein positron emission tomography imaging study with [11C]PBR28.

Basic science investigations have consistently shown that repeated exposure to psychostimulant drugs, such as cocaine, activate the immune response and lead to inflammatory changes in the brain. No previous in vivo studies have confirmed this observation in chronic cocaine-abusing humans. To test this hypothesis, we used positron emission tomography imaging to measure the binding of [(11)C]PBR28 to the 18 kDa translocator protein (TSPO), a marker for microglial activation in a group of 15 recently abstinent cocaine abusers and 17 matched healthy controls. [(11)C]PBR28 volumes of distribution expressed relative to total plasma ligand concentration (VT) were measured in subjects with kinetic analysis using the arterial input function. Subjects were also genotyped for the TSPO alanine147 threonine (Ala147Thr, rs6971) polymorphism that has been shown to influence the in vivo binding of PBR28 to TSPO. Consistent with previous reports, the TSPO Ala147Thr genotype predicted the in vivo binding of [(11)C]PBR28. No significant differences in [(11)C]PBR28 VT were observed in the cortical and subcortical regions in cocaine abusers compared with healthy controls. The results of this in vivo study do not support increased TSPO expression and, by extension, microglial activation in chronic cocaine-abusing humans. Further research with more direct markers of microglial activation is necessary to conclusively rule out neuroinflammation in cocaine dependence.

HLA associations in schizophrenia: are we re-discovering the wheel?

Associations between human leukocyte antigen (HLA) polymorphisms on chromosome 6p and schizophrenia (SZ) risk have been evaluated for over five decades. Numerous case-control studies from the candidate gene era analyzed moderately sized samples and reported nominally significant associations with several loci in the HLA region (sample sizes, n = 100-400). The risk conferred by individual alleles was modest (odds ratios < 2.0). The basis for the associations could not be determined, though connections with known immune and auto-immune abnormalities in SZ were postulated. Interest in the HLA associations has re-emerged following several recent genome-wide association studies (GWAS); which utilized 10- to 100-fold larger samples and also identified associations on the short arm of chromosome 6. Unlike the earlier candidate gene studies, the associations are statistically significant following correction for multiple comparisons. Like the earlier studies; they have modest effect sizes, raising questions about their utility in risk prediction or pathogenesis research. In this review, we summarize the GWAS and reflect on possible bases for the associations. Suggestions for future research are discussed. We favor, in particular; efforts to evaluate local population sub-structure as well as further evaluation of immune-related variables in future studies.

Prediction of psychosis onset in Alzheimer disease: the role of depression symptom severity and the HTR2A T102C polymorphism.

Psychotic symptoms in Alzheimer disease (AD + P) identify a heritable phenotype associated with a more severe course. We recently found an association of AD + P with depression symptom severity. Reports have shown an association of a serotonin-2A receptor (HTR2A) gene T102C polymorphism with AD + P and with depression during AD. We examined the interaction of this common genetic polymorphism with depression and increased psychosis risk. Subjects with possible or probable AD or mild cognitive impairment (MCI) without psychosis at study entry were genotyped for the HTR2A T102C polymorphism and reassessed every 6 months until psychosis onset. Psychotic and depressive symptoms were rated using the CERAD behavioral rating scale (CBRS). Cox proportional hazard models with time-dependent covariates were used to examine associations with psychosis onset. A total of 324 Caucasian subjects completed at least one follow-up exam. Depressive symptom severity was a strong predictor of psychosis onset. Neither psychosis onset nor depression severity was associated with the HTR2A genotype. Genotype interacted with depression severity to moderate the risk of AD + P onset. This did not result from an interaction of HTR2A genotype with antidepressant use. Psychosis onset in AD is strongly associated with severity of depressive symptoms, an association that may be modified by HTR2A genotype.