Search bioRxiv⌕ Search

Biology subjects

Wynshaw-Boris, A.

Publications and source records attributed to Wynshaw-Boris, A..

7 recordsLinked to original sources

Transcriptional Mapping of Neuro-Immune Interactions during Homeostasis and HIV infection using Microglia-containing Human Cerebral Assembloids

BackgroundA significant number of people with HIV-1 still experience neurocognitive impairments (NCI), despite effective antiretroviral treatment. HIV-NCI is diverse and multifactorial, with mechanisms that cause its development and progression still not fully understood. We examined early HIV-related changes in brain stability and studied neuroimmune interactions at the single-cell level to better understand how NCI develops. MethodsTo model changes in brain homeostasis, we developed an advanced human iPSC-derived 3D cerebral assembloid model that includes microglia, by co-developing neural progenitor cells with tdTomato-tagged and CD34+ cell-derived microglial precursors. Assembloids were infected with a macrophage R5-tropic HIV-1 strain NL-AD8. Viral spread was measured using a proviral DNA assay, qPCR for HIV RNA, and 3D immunostaining for Tat protein. Single-cell transcriptomics with tdTomato lineage tracing revealed HIV-1 induced disturbances and cell-type-specific responses. The niche net algorithm was used to identify ligand-receptor interactions between microglia and the brain microenvironment during homeostasis and HIV infection. ResultsHighly ramified tdTomato+ IBA-1+ microglia were evenly distributed throughout the assembloids within 15 days of culture. Single-cell transcriptomics identified microglia, excitatory/inhibitory neurons, astrocytes, and oligodendrocyte precursors within the assembloids. Neurons in microglia-containing assembloids upregulated genes related to neurotransmission, synaptogenesis, and neuronal development compared to neurons in organoids without microglia. Niche net analysis showed microglia-derived neurotropic ligands supported neuronal and astrocytic differentiation. The R5-tropic HIV-1 specifically targeted microglia, inducing a reactive phenotype that transmitted interferon and pro-inflammatory signals to nearby cells and increased MHC-I antigen-presentation genes. Notably, neuroprotective ligands from non-glial cells and bystander microglia in the assembloids attempted to counteract HIV-related inflammation and promote neural repair. ConclusionsOur microglia-containing assembloid model replicates in vivo neurodevelopmental interactions, allowing high-resolution analysis of homeostatic and HIV-induced responses across different brain cell types. Homeostatic microglia support neuronal health, while HIV infection triggers a reactive state that spreads inflammatory signals within the brain environment. The presence of multiple glial and non-glial populations uncovered previously unknown crosstalk, including bystander microglial phenotypes and neuroprotective signaling mechanisms that counteract inflammation. These findings emphasize early HIV responses that balance injury and adaptation, offering insights for developing therapies that target microglial activation, boost neuroprotection, and address HIV reservoirs in the brain.

microbiology↗

Autism risk genes converge on PBX1 to govern neural cell growth

The alteration of neural progenitor cell (NPC) proliferation underlies autism spectrum disorders (ASD). It remains unclear whether targeting convergent downstream targets among mutations from different genes and individuals can rescue this alteration. We identified PBX1 as a convergent target of three autism risk genes: CTNNB1, PTEN, and DVL3, using isogenic iPSC-derived 2D NPCs. Overexpression of the PBX1a isoform effectively rescued increased NPC proliferation in all three isogenic ASD-related variants. Dysregulation of PBX1 in NPCs was further confirmed in publicly available datasets from other models of ASD. These findings spotlight PBX1, known to play important roles during olfactory bulb/adult neurogenesis and in multiple cancers, as an unexpected and key downstream target, influencing NPC proliferation in ASD and neurodevelopmental syndromes.

neuroscience↗

Three-dimensional tissue platform co-laid with native collagen fibers and cells for phenotypic screening of stem cell interactions

Phenotypic screening of cell-cell and cell-matrix interactions is critical yet challenging for drug discovery and disease modeling. In this study, a scalable 3D tissue platform was developed by co-laying extracted natural insoluble collagen fibers, mesenchymal stem cells, endothelial cells, and neural progenitor cells for phenotypic screening. Cell growth and interactions were enhanced in the co-laid platform, evident through increased cell proliferation, viability, and vascularization. Dense vascular networks rapidly formed through cell-cell and cell-matrix interactions without adding a traditionally needed growth factor set. Both in vitro and implantation studies confirmed that these blood vessels were of human origin. To evaluate the phenotypic screening of cell-cell and cell-matrix interactions, we propose a phenotype screening prototype for stem cell interactions that utilized multivariate analysis encompassing both cell-cell and cell-matrix interactions and demonstrated its effectiveness to screen vasculature formation and autism spectrum disorder (ASD) models. Using the prototype, we confirmed that collagen crosslinking, ROCK, WNT, and YAP pathways impact vasculogenesis. In addition, ASD donor-derived neural progenitor cells can be distinguished from non-ASD control donor-derived neural progenitor cells.

bioengineering↗

Neuronal lineage tracing from progenitors in human cortical organoids reveals novel mechanisms of human neuronal production, diversity, and disease

The contribution of progenitor subtypes to generate the billions of neurons during human cortical neurogenesis is not well understood. We developed the Cortical ORganoid Lineage Tracing (COR-LT) system for human cortical organoids. Differential fluorescent reporter activation in distinct progenitor cells leads to permanent reporter expression, enabling the progenitor cell lineage of neurons to be determined. Surprisingly, nearly all neurons produced in cortical organoids were generated indirectly from intermediate progenitor cells. Additionally, neurons of different progenitor lineages were transcriptionally distinct. Isogenic lines made from an autistic individual with and without a likely pathogenic variant in the CTNNB1 gene demonstrated that the variant substantially altered the proportion of neurons derived from specific progenitor cell lineages, as well as the lineage-specific transcriptional profiles of these neurons, suggesting a pathogenic mechanism for this mutation. These results suggest individual progenitor subtypes play unique roles in generating the diverse neurons of the human cerebral cortex. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=194 SRC="FIGDIR/small/545314v1_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@da0038org.highwire.dtl.DTLVardef@44997dorg.highwire.dtl.DTLVardef@1b90ff2org.highwire.dtl.DTLVardef@c5dbcd_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphic AbstractC_FLOATNO C_FIG

neuroscience↗

MOPD I patient-derived cerebral organoids model microcephaly showing premature neurogenesis due to disrupted mitotic spindle orientation.

Mutations in the single-copy RNU4ATAC gene, which encodes U4atac snRNA of the minor spliceosome are linked to the developmental disorder microcephalic osteodysplastic primordial dwarfism type I (MOPD I). Partial loss-of-function mutations of U4atac snRNA lead to a poor prognosis, with less than three year survival. The most prominent characteristic of MOPD I is disrupted central nervous system development resulting in severe microcephaly and lissencephaly. In this study, we used self-organizing 3D cerebral organoids from patient-derived induced pluripotent stem cells (iPSCs) to investigate defective cellular events that disturb the laminar organization of the cortex and influence brain topology. We analyzed organoids from iPSCs homozygous for the partial loss-of-function U4atac snRNA 51G>A mutation and compared them to isogenic organoids obtained from iPSCs expressing wild-type U4atac snRNA, using immunostaining and 10X Genomics single-cell RNA sequencing. In our MOPD I organoids, we observed: a) reduced proliferation accompanied by premature neurogenesis depleting the neuro-progenitor pool due to an increased frequency of horizontal cell divisions in the ventricular zone; b) reduced numbers of intermediate progenitor and outer radial glial cells in the outer sub-ventricular zone; and c) defective radial neuronal migration, which is critical for cortical expansion in humans. Our findings therefore provide insight into MOPD I cellular pathogenesis and underline the value of these cerebral organoids as model systems for human neurodevelopmental disorders.

neuroscience↗

Autism-specific PTEN p.I135L mutation and an autism genetic background combine to dysregulate cortical neurogenesis

Alterations in cortical neurogenesis are implicated in neurodevelopmental disorders including autism spectrum disorders (ASDs). The contribution of genetic backgrounds, in additional to ASD risk genes, on cortical neurogenesis remain understudied. Here, using isogenic induced pluripotent stem cell (iPSC)-derived neural progenitor cells (NPCs) and cortical organoid models, we report that a heterozygous PTEN p.I135L mutation found in an ASD patient with macrocephaly activates PI3K/AKT and dysregulates cortical neurogenesis in an ASD genetic background-dependent fashion. Transcriptome analysis at both bulk and single cell level revealed PTEN p.I135L mutation and ASD genetic background affected genes involved in neurogenesis, neural development and synapse signaling. We also found that this PTEN p.I135L mutation led to overproduction of NPC subtypes as well as neuronal subtypes including both deep and upper layer neurons in its ASD background, but not when introduced into a control genetic background. These findings provide experimental evidence that both a PTEN p.I135L mutation and ASD genetic background contribute to cellular features consistent with ASD associated with macrocephaly.

genetics↗

LIS1 determines cleavage plane positioning by regulating actomyosin-mediated cell membrane contractility

Heterozygous loss of human PAFAH1B1 (coding for LIS1) results in the disruption of neurogenesis and neuronal migration via dysregulation of microtubule (MT) stability and dynein motor function/localization that alters mitotic spindle orientation, chromosomal segregation, and nuclear migration. Recently, human induced pluripotent stem cell (iPSC) models revealed an important role for LIS1 in controlling the length of terminal cell divisions of outer radial glial (oRG) progenitors, suggesting cellular functions of LIS1 in regulating neural progenitor cell (NPC) daughter cell separation. Here we examined the late mitotic stages NPCs in vivo and mouse embryonic fibroblasts (MEFs) in vitro from Lis1-deficient mutants. Lis1-deficient neocortical NPCs and MEFs similarly exhibited cleavage plane displacement with mislocalization of furrow-associated markers, associated with actomyosin dysfunction and cell membrane hyper-contractility. Thus, it suggests LIS1 acts as a key molecular link connecting MTs/dynein and actomyosin, ensuring that cell membrane contractility is tightly controlled to execute proper daughter cell separation.

developmental biology↗