Biology subjects

Wynshaw-Boris, A.

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

4 recordsLinked to original sources

bioRxiv2023

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↗

bioRxiv2022

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↗

bioRxiv2022

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↗

bioRxiv2019

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↗