Neurological complications are common in patients with COVID-19. Although severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causal pathogen of COVID-19, has been detected in some ...patient brains, its ability to infect brain cells and impact their function is not well understood. Here, we investigated the susceptibility of human induced pluripotent stem cell (hiPSC)-derived monolayer brain cells and region-specific brain organoids to SARS-CoV-2 infection. We found that neurons and astrocytes were sparsely infected, but choroid plexus epithelial cells underwent robust infection. We optimized a protocol to generate choroid plexus organoids from hiPSCs and showed that productive SARS-CoV-2 infection of these organoids is associated with increased cell death and transcriptional dysregulation indicative of an inflammatory response and cellular function deficits. Together, our findings provide evidence for selective SARS-CoV-2 neurotropism and support the use of hiPSC-derived brain organoids as a platform to investigate SARS-CoV-2 infection susceptibility of brain cells, mechanisms of virus-induced brain dysfunction, and treatment strategies.
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•SARS-CoV-2 minimally infects human neurons and astrocytes in 2D and brain organoids•Model developed for hiPSC-derived choroid plexus organoids (CPOs)•SARS-CoV-2 productively infects CPOs and increases cell death•SARS-CoV-2 CPO infection leads to transcriptional upregulation of inflammatory genes
SARS-CoV-2 causes neurological symptoms in a significant portion of patients with COVID-19. Ming and colleagues tested SARS-CoV-2 neurotropism by using monolayer neural cells and brain organoids generated from human pluripotent stem cells and show minimal neuron and astrocyte infection but efficient choroid plexus infection, leading to cell death and functional deficits.
Human brain organoids represent remarkable platforms for recapitulating features of human brain development and diseases. Existing organoid models do not resolve fine brain subregions, such as ...different nuclei in the hypothalamus. We report the generation of arcuate organoids (ARCOs) from human induced pluripotent stem cells (iPSCs) to model the development of the human hypothalamic arcuate nucleus. Single-cell RNA sequencing of ARCOs revealed significant molecular heterogeneity underlying different arcuate cell types, and machine learning-aided analysis based on the neonatal human hypothalamus single-nucleus transcriptome further showed a human arcuate nucleus molecular signature. We also explored ARCOs generated from Prader-Willi syndrome (PWS) patient iPSCs. These organoids exhibit aberrant differentiation and transcriptomic dysregulation similar to postnatal hypothalamus of PWS patients, indicative of cellular differentiation deficits and exacerbated inflammatory responses. Thus, patient iPSC-derived ARCOs represent a promising experimental model for investigating nucleus-specific features and disease-relevant mechanisms during early human arcuate development.
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•A protocol for arcuate organoids (ARCOs) to model a discrete brain subregion•A single-cell transcriptome atlas of human neonatal hypothalamus•Similar molecular signatures between ARCOs and human arcuate nucleus•Differentiation and functional deficits in Prader-Willi syndrome patient ARCOs
Current brain organoid models do not resolve fine subregions of the human brain. Ming et al. established a method to generate hypothalamic arcuate organoids from human induced pluripotent stem cells, which exhibit neuronal subtype diversity and molecular signatures of human arcuate nucleus and can be used to model Prader-Willi syndrome.
Paclitaxel shows little benefit in the treatment of glioma due to poor penetration across the blood-brain barrier (BBB). Low-intensity pulsed ultrasound (LIPU) with microbubble injection transiently ...disrupts the BBB allowing for improved drug delivery to the brain. We investigated the distribution, toxicity, and efficacy of LIPU delivery of two different formulations of paclitaxel, albumin-bound paclitaxel (ABX) and paclitaxel dissolved in cremophor (CrEL-PTX), in preclinical glioma models.
The efficacy and biodistribution of ABX and CrEL-PTX were compared with and without LIPU delivery. Antiglioma activity was evaluated in nude mice bearing intracranial patient-derived glioma xenografts (PDX). Paclitaxel biodistribution was determined in sonicated and nonsonicated nude mice. Sonications were performed using a 1 MHz LIPU device (SonoCloud), and fluorescein was used to confirm and map BBB disruption. Toxicity of LIPU-delivered paclitaxel was assessed through clinical and histologic examination of treated mice.
Despite similar antiglioma activity
, ABX extended survival over CrEL-PTX and untreated control mice with orthotropic PDX. Ultrasound-mediated BBB disruption enhanced paclitaxel brain concentration by 3- to 5-fold for both formulations and further augmented the therapeutic benefit of ABX. Repeated courses of LIPU-delivered CrEL-PTX and CrEL alone were lethal in 42% and 37.5% of mice, respectively, whereas similar delivery of ABX at an equivalent dose was well tolerated.
Ultrasound delivery of paclitaxel across the BBB is a feasible and effective treatment for glioma. ABX is the preferred formulation for further investigation in the clinical setting due to its superior brain penetration and tolerability compared with CrEL-PTX.
The roles of tumor-associated macrophages (TAMs) and circulating monocytes in human cancer are poorly understood. Here, we show that monocyte subpopulation distribution and transcriptomes are ...significantly altered by the presence of endometrial and breast cancer. Furthermore, TAMs from endometrial and breast cancers are transcriptionally distinct from monocytes and their respective tissue-resident macrophages. We identified a breast TAM signature that is highly enriched in aggressive breast cancer subtypes and associated with shorter disease-specific survival. We also identified an auto-regulatory loop between TAMs and cancer cells driven by tumor necrosis factor alpha involving SIGLEC1 and CCL8, which is self-reinforcing through the production of CSF1. Together these data provide direct evidence that monocyte and macrophage transcriptional landscapes are perturbed by cancer, reflecting patient outcomes.
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•Cancer alters circulating monocytic populations and their transcriptomes•Tumor-associated macrophages show tissue-specific programming•Tumor-associated macrophages’ gene signature correlates with poor clinical outcome•Tumor-associated macrophages enhance cancer cells malignancy through CCL8
Cassetta et al. identify a breast cancer tumor-associated macrophage (TAM) transcriptome that is different from those of monocytes and tissue-resident macrophages, and which is associated with shorter disease-specific survival, and they demonstrate crosstalk between tumor cells and TAMs via SIGLEC1, CCL8, and CSF1.
Chelatable, mobile forms of divalent zinc, Zn(II), play essential signaling roles in mammalian biology. A complex network of zinc import and transport proteins has evolved to control zinc ...concentration and distribution on a subcellular level. Understanding the action of mobile zinc requires tools that can detect changes in Zn(II) concentrations at discrete cellular locales. We present here a zinc-responsive, reaction-based, targetable probe based on the diacetyled form of Zinpyr-1. The compound, (6-amidoethyl)triphenylphosphonium Zinpyr-1 diacetate (DA-ZP1-TPP), is essentially nonfluorescent in the metal-free state; however, exposure to Zn(II) triggers metal-mediated hydrolysis of the acetyl groups to afford a large, rapid, and zinc-induced fluorescence response. DA-ZP1-TPP is insensitive to intracellular esterases over a 2-h period and is impervious to proton-induced turn-on. A TPP unit is appended for targeting mitochondria, as demonstrated by live cell fluorescence imaging studies. The practical utility of DA-ZP1-TPP is demonstrated by experiments revealing that, in contrast to healthy epithelial prostate cells, tumorigenic cells are unable to accumulate mobile zinc within their mitochondria.
Objective To determine rates of publication and reporting of results within two years for all completed clinical trials registered in ClinicalTrials.gov across leading academic medical centers in the ...United States.Design Cross sectional analysis.Setting Academic medical centers in the United States.Participants Academic medical centers with 40 or more completed interventional trials registered on ClinicalTrials.gov.Methods Using the Aggregate Analysis of ClinicalTrials.gov database and manual review, we identified all interventional clinical trials registered on ClinicalTrials.gov with a primary completion date between October 2007 and September 2010 and with a lead investigator affiliated with an academic medical center.Main outcome measures The proportion of trials that disseminated results, defined as publication or reporting of results on ClinicalTrials.gov, overall and within 24 months of study completion.Results We identified 4347 interventional clinical trials across 51 academic medical centers. Among the trials, 1005 (23%) enrolled more than 100 patients, 1216 (28%) were double blind, and 2169 (50%) were phase II through IV. Overall, academic medical centers disseminated results for 2892 (66%) trials, with 1560 (35.9%) achieving this within 24 months of study completion. The proportion of clinical trials with results disseminated within 24 months of study completion ranged from 16.2% (6/37) to 55.3% (57/103) across academic medical centers. The proportion of clinical trials published within 24 months of study completion ranged from 10.8% (4/37) to 40.3% (31/77) across academic medical centers, whereas results reporting on ClinicalTrials.gov ranged from 1.6% (2/122) to 40.7% (72/177).Conclusions Despite the ethical mandate and expressed values and mission of academic institutions, there is poor performance and noticeable variation in the dissemination of clinical trial results across leading academic medical centers.
Increasing evidence implicates the critical roles of various epitranscriptomic RNA modifications in different biological processes. Methyltransferase METTL8 installs 3-methylcytosine (m3C) ...modification of mitochondrial tRNAs in vitro; however, its role in intact biological systems is unknown. Here, we show that Mettl8 is localized in mitochondria and installs m3C specifically on mitochondrial tRNAThr/Ser(UCN) in mouse embryonic cortical neural stem cells. At molecular and cellular levels, Mettl8 deletion in cortical neural stem cells leads to reduced mitochondrial protein translation and attenuated respiration activity. At the functional level, conditional Mettl8 deletion in mice results in impaired embryonic cortical neural stem cell maintenance in vivo, which can be rescued by pharmacologically enhancing mitochondrial functions. Similarly, METTL8 promotes mitochondrial protein expression and neural stem cell maintenance in human forebrain cortical organoids. Together, our study reveals a conserved epitranscriptomic mechanism of Mettl8 and mitochondrial tRNA m3C modification in maintaining embryonic cortical neural stem cells in mice and humans.
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•Mettl8 installs m3C modification on mt-tRNAThr/Ser(UCN) in cortical neural stem cells•Mettl8 regulates mitochondrial protein translation and function in neural stem cells•Mettl8-deleted mice exhibit accelerated embryonic cortical neural stem cell depletion•METTL8 plays a conserved role in neurogenesis in human forebrain organoids as in mice
Zhang et al. identified an epitranscriptomic mechanism regulating cortical neural stem cells in the embryonic mouse brain and human forebrain organoids. Specifically, Mettl8 installs m3C modification on mitochondrial tRNAThr/Ser(UNC), which regulates mitochondrial protein translation and function, and loss of Mettl8 leads to accelerated embryonic cortical neural stem cell depletion.
Glioblastomas exhibit vast inter- and intra-tumoral heterogeneity, complicating the development of effective therapeutic strategies. Current in vitro models are limited in preserving the cellular and ...mutational diversity of parental tumors and require a prolonged generation time. Here, we report methods for generating and biobanking patient-derived glioblastoma organoids (GBOs) that recapitulate the histological features, cellular diversity, gene expression, and mutational profiles of their corresponding parental tumors. GBOs can be generated quickly with high reliability and exhibit rapid, aggressive infiltration when transplanted into adult rodent brains. We further demonstrate the utility of GBOs to test personalized therapies by correlating GBO mutational profiles with responses to specific drugs and by modeling chimeric antigen receptor T cell immunotherapy. Our studies show that GBOs maintain many key features of glioblastomas and can be rapidly deployed to investigate patient-specific treatment strategies. Additionally, our live biobank establishes a rich resource for basic and translational glioblastoma research.
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•Rapid establishment of glioblastoma organoids (GBOs) in a defined medium with biobank•GBOs maintain parental tumor cellular heterogeneity, gene expression, and mutations•GBO transplantation exhibits efficient engraftment and aggressive infiltration•Tumor-specific treatment responses in GBOs to drugs and CAR-T cells
A rapid and reliable method to generate patient-derived glioblastoma organoids captures the features and diversity of their respective parental tumors to allow for testing personalized therapies correlated to organoid profile and the establishment of a biobank for further basic and translational glioblastoma research.
Neurological disorders are challenging to study given the complexity and species-specific features of the organ system. Brain organoids are three dimensional structured aggregates of neural tissue ...that are generated by self-organization and differentiation from pluripotent stem cells under optimized culture conditions. These brain organoids exhibit similar features of structural organization and cell type diversity as the developing human brain, creating opportunities to recapitulate disease phenotypes that are not otherwise accessible. Here we review the initial attempt in the field to apply brain organoid models for the study of many different types of human neurological disorders across a wide range of etiologies and pathophysiologies. Forthcoming advancements in both brain organoid technology as well as analytical methods have significant potentials to advance the understanding of neurological disorders and to uncover opportunities for meaningful therapeutic intervention.
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