Biology subjects

Willsey, H. R.

Publications and source records attributed to Willsey, H. R..

7 recordsLinked to original sources

bioRxiv2026

Epilepsy-associated potassium channel KCNT1 is required for multiciliated cell development in Xenopus

Pathogenic variants in the gene KCNT1, which encodes a sodium-activated potassium channel, cause a severe neurodevelopmental disorder with intractable epilepsy. In addition to seizures, affected individuals commonly present with severe respiratory issues and structural heart defects not commonly observed in other genetic pediatric epilepsies, suggesting additional developmental functions for KCNT1 in organs beyond the brain. Here, we characterized the spectrum of clinical diagnoses present in a cohort of 46 individuals with pathogenic variants in KCNT1, ranging from 0 to 19 years of age, by medical record review. We documented the prevalence of diagnoses across organ systems, including dependence on assisted breathing, congenital structural heart defects, urinary dysfunction, and spine deformities, among others. Next, we explored the embryonic expression and function of KCNT1 in diploid frogs (Xenopus tropicalis) and observed expression in developing ciliated tissues such as the brain, heart, kidney, and epidermis. Embryonic perturbation of KCNT1 disrupted developmental signaling pathways and caused ciliogenesis defects in the mucociliary epidermis, a common model for the human airway. Loss of KCNT1 disrupted development of multiciliated cells, reminiscent of recent work on the ion channel Piezo1. Consistently, pharmacological inhibition of Piezo signaling enhanced the ciliogenesis phenotype observed following KCNT1 inhibition, while activation of Piezo1 activity partially rescued ciliogenesis in the context of KCNT1 inhibition. Together, this work establishes that KCNT1 has embryonic functions in Xenopus beyond regulating neuronal activity, specifically in multiciliated cell development, and identifies an interaction with pharmacologically-tractable Piezo channels that may be productive for therapeutic efforts.

developmental biology↗

bioRxiv2024

Convergence of autism proteins at the cilium

Hundreds of high-confidence autism genes have been identified, yet the relevant etiological mechanisms remain unclear. Gene ontology analyses have repeatedly identified enrichment of proteins with annotated functions in gene expression regulation and neuronal communication. However, proteins are often pleiotropic and these annotations are inherently incomplete. Our recent autism functional genetics work has suggested that these genes may share a common mechanism at the cilium, a membrane-bound organelle critical for neurogenesis, brain patterning, and neuronal activity-all processes strongly implicated in autism. Moreover, autism commonly co-occurs with conditions that are known to involve ciliary-related pathologies, including congenital heart disease, hydrocephalus, and blindness. However, the role of autism genes at the cilium has not been systematically investigated. Here we demonstrate that autism proteins spanning disparate functional annotations converge in expression, localization, and function at cilia, and that patients with pathogenic variants in these genes have cilia-related co-occurring conditions and biomarkers of disrupted ciliary function. This degree of convergence among genes spanning diverse functional annotations strongly suggests that cilia are relevant to autism, as well as to commonly co-occurring conditions, and that this organelle should be explored further for therapeutic potential. One-Sentence SummaryAutism genes of diverse functional annotations converge at cilia, deepening our understanding of underlying autism biology and co-occurring conditions.

cell biology↗

bioRxiv2024

Autism gene variants disrupt enteric neuron migration and cause gastrointestinal dysmotility

The comorbidity of autism spectrum disorders and severe gastrointestinal symptoms is well-established, yet the molecular underpinnings remain unknown. The identification of high-confidence large-effect autism risk genes offers the opportunity to identify convergent, underlying biology by studying these genes in the context of the gastrointestinal system. Here we show that the expression of these genes is enriched in human prenatal gut neurons as well as their migratory progenitors, suggesting that the development and/or function of these neurons may be disrupted by autism-associated pathogenic variants, leading to gastrointestinal dysfunction. Here we document the prevalence of gastrointestinal issues in patients with large-effect variants in sixteen of these genes, highlighting dysmotility, consistent with potential enteric neuron dysfunction. Using the high-throughput diploid frog Xenopus tropicalis, we individually target five of these genes (SYNGAP1, CHD8, SCN2A, CHD2, and DYRK1A) and observe disrupted enteric neuronal progenitor migration for each. More extensive analysis of DYRK1A reveals that perturbation causes gut dysmotility in vivo, which can be ameliorated by treatment with a selective serotonin reuptake inhibitor (escitalopram) or a serotonin receptor 6 agonist, identified by in vivo drug screening. This work suggests that atypical development of enteric neurons contributes to the gastrointestinal distress commonly seen in individuals with autism and that increasing serotonin signaling may be a productive therapeutic avenue.

neuroscience↗

bioRxiv2023

Autism genes converge on microtubule biology and RNA-binding proteins during excitatory neurogenesis

Recent studies have identified over one hundred high-confidence (hc) autism spectrum disorder (ASD) genes. Systems biological and functional analyses on smaller subsets of these genes have consistently implicated excitatory neurogenesis. However, the extent to which the broader set of hcASD genes are involved in this process has not been explored systematically nor have the biological pathways underlying this convergence been identified. Here, we leveraged CROP-Seq to repress 87 hcASD genes in a human in vitro model of cortical neurogenesis. We identified 17 hcASD genes whose repression significantly alters developmental trajectory and results in a common cellular state characterized by disruptions in proliferation, differentiation, cell cycle, microtubule biology, and RNA-binding proteins (RBPs). We also characterized over 3,000 differentially expressed genes, 286 of which had expression profiles correlated with changes in developmental trajectory. Overall, we uncovered transcriptional disruptions downstream of hcASD gene perturbations, correlated these disruptions with distinct differentiation phenotypes, and reinforced neurogenesis, microtubule biology, and RBPs as convergent points of disruption in ASD.

systems biology↗

bioRxiv2023

A foundational atlas of autism protein interactions reveals molecular convergence

Translating high-confidence (hc) autism spectrum disorder (ASD) genes into viable treatment targets remains elusive. We constructed a foundational protein-protein interaction (PPI) network in HEK293T cells involving 100 hcASD risk genes, revealing over 1,800 PPIs (87% novel). Interactors, expressed in the human brain and enriched for ASD but not schizophrenia genetic risk, converged on protein complexes involved in neurogenesis, tubulin biology, transcriptional regulation, and chromatin modification. A PPI map of 54 patient-derived missense variants identified differential physical interactions, and we leveraged AlphaFold-Multimer predictions to prioritize direct PPIs and specific variants for interrogation in Xenopus tropicalis and human forebrain organoids. A mutation in the transcription factor FOXP1 led to reconfiguration of DNA binding sites and altered development of deep cortical layer neurons in forebrain organoids. This work offers new insights into molecular mechanisms underlying ASD and describes a powerful platform to develop and test therapeutic strategies for many genetically-defined conditions.

systems biology↗

bioRxiv2022

Pleiotropy of autism-associated chromatin regulators

Gene ontology analyses of high confidence autism spectrum disorder (hcASD) risk genes have historically highlighted chromatin regulation and synaptic function as major contributors to pathobiology. Our recent functional work in vivo has additionally implicated microtubule biology and identified disrupted cellular proliferation as a convergent ASD phenotype. As many chromatin regulators, including ASD risk genes ADNP and CHD3, are known to directly regulate both tubulins and histones, we studied the five chromatin regulators most strongly associated with ASD (ADNP, CHD8, CHD2, POGZ, and SUV420H1/KMT5B) specifically with respect to microtubule biology. We observe that all five localize to microtubules of the mitotic spindle in vitro and in vivo. Further in-depth investigation of CHD2 provides evidence that patient-derived mutations lead to a range of microtubule-related phenotypes, including disrupted localization of the protein at the mitotic spindle, spindle defects, cell cycle stalling, DNA damage, and cell death. Lastly, we observe that ASD genetic risk is significantly enriched among microtubule-associated proteins, suggesting broader relevance. Together, these results provide further evidence that the role of tubulin biology and cellular proliferation in ASD warrant further investigation and highlight the pitfalls of relying solely on annotated gene functions in the search for pathological mechanisms.

developmental biology↗

bioRxiv2021

Development of a Low-Cost System for Simultaneous Longitudinal Biological Imaging

Simultaneous longitudinal imaging across multiple conditions and replicates has been crucial for scientific studies aiming to understand biological processes and disease. Yet, imaging systems capable of accomplishing these tasks are economically unattainable for most academic and teaching laboratories around the world. Here we propose the Picroscope, which is the first low cost system for simultaneous longitudinal biological imaging made primarily using off-the-shelf and 3D-printed materials. The Picroscope is compatible with standard 24-well cell culture plates and captures 3D z-stack image data. The Picroscope can be controlled remotely, allowing for automatic imaging with minimal intervention from the investigator. Here we use this system in a range of applications. We gathered longitudinal whole organism image data for frogs, zebrafish and planaria worms. We also gathered image data inside an incubator to observe 2D monolayers and 3D mammalian tissue culture models. Using this tool, we can measure the behavior of entire organisms or individual cells over long time periods.

bioengineering↗