Biology subjects

Maguire, J. A.

Publications and source records attributed to Maguire, J. A..

7 recordsLinked to original sources

bioRxiv2026

Deletion of TUBB4A mitigates the oligodendrocyte and neuronal deficits in human iPSCs derived from individuals affected by H-ABC

TUBB4A-related leukodystrophy (TUBB4A-LD) is a rare neurologic disorder with a broad spectrum of phenotypes, including severe early infantile encephalopathy, late infantile Hypomyelination with Atrophy of the Basal ganglia and Cerebellum (H-ABC), and milder late infantile forms. H-ABC is closely associated with a recurrent pathogenic variant, p.Asp249Asn, in the gene encoding tubulin beta class IVA (TUBB4A), a microtubule component. H-ABC presents with progressive dystonia, mobility loss, aphasia, and swallowing dysfunction in childhood. H-ABC results in cell-autonomous deficits in oligodendrocytes (OLs), cerebellar granule neurons, and medium spiny neurons (MSNs). Antisense oligonucleotides targeting Tubb4a can alleviate symptoms in H-ABC mouse models. However, the efficacy and safety of TUBB4A knockout in human cells remain poorly understood. We studied patient-derived TUBB4AD249N, TUBB4A KO, and control individual pluripotent stem cells (iPSCs). TUBB4AD249N iPSC-derived OLs failed to mature, showing less complexity and myelination, reduced microtubule acetylation and detyrosination. TUBB4AD249N iPSC-derived MSNs also showed impaired maturation and neurite extension. TUBB4A KO in mutant iPSCs reduced cellular deficits and was well tolerated. These findings support that suppression of TUBB4A could be a safe, effective therapy for TUBB4A-LD.

neuroscience↗

bioRxiv2023

A novel iPSC model reveals selective vulnerability of neurons in Multiple Sulfatase Deficiency

Multiple sulfatase deficiency (MSD) is an ultra-rare, inherited lysosomal storage disease caused by mutations in the gene sulfatase modifying factor 1 (SUMF1). MSD is characterized by the functional deficiency of all sulfatase enzymes, leading to the storage of sulfated substrates including glycosaminoglycans (GAGs), sulfolipids, and steroid sulfates. Patients with MSD experience severe neurological impairment, hearing loss, organomegaly, corneal clouding, cardiac valve disease, dysostosis multiplex, contractures, and ichthyosis. Here, we generated a novel human model of MSD by reprogramming patient peripheral blood mononuclear cells to establish an MSD iPSC line (SUMF1 p.A279V). We also generated an isogenic control iPSC line by correcting the pathogenic variant with CRISPR/Cas9 gene editing. We successfully differentiated these iPSC lines into neural progenitor cells (NPCs) and NGN2-induced neurons (NGN2-iN) to model the neuropathology of MSD. Mature neuronal cells exhibited decreased SUMF1 gene expression, increased lysosomal stress, impaired neurite outgrowth and maturation, reduced sulfatase activities, and GAG accumulation. Interestingly, MSD iPSCs and NPCs did not exhibit as severe of phenotypes, suggesting that as neurons differentiate and mature, they become more vulnerable to loss of SUMF1. In summary, we demonstrate that this human iPSC-derived neuronal model recapitulates the cellular and biochemical features of MSD. These cell models can be used as tools to further elucidate the mechanisms of MSD pathology and for the development of therapeutics.

cell biology↗

bioRxiv2023

Tropomyosin 1 deficiency facilitates cell state transitions and enhances hemogenic endothelial cell specification during hematopoiesis

Tropomyosins coat actin filaments and impact actin-related signaling and cell morphogenesis. Genome-wide association studies have linked Tropomyosin 1 (TPM1) with human blood trait variation. Prior work suggested that TPM1 regulated blood cell formation in vitro, but it was unclear how or when TPM1 affected hematopoiesis. Using gene-edited induced pluripotent stem cell (iPSC) model systems, TPM1 knockout was found to augment developmental cell state transitions, as well as TNF and GTPase signaling pathways, to promote hemogenic endothelial (HE) cell specification and hematopoietic progenitor cell (HPC) production. Single-cell analyses showed decreased TPM1 expression during human HE specification, suggesting that TPM1 regulated in vivo hematopoiesis via similar mechanisms. Indeed, analyses of a TPM1 gene trap mouse model showed that TPM1 deficiency enhanced the formation of HE during embryogenesis. These findings illuminate novel effects of TPM1 on developmental hematopoiesis.

cell biology↗

bioRxiv2023

Variant-to-function analysis of the childhood obesity chr12q13 locus implicates rs7132908 as a causal variant within the 3' UTR of FAIM2

The ch12q13 obesity locus is among the most significant childhood obesity loci identified in genome-wide association studies. This locus resides in a non-coding region within FAIM2; thus, the underlying causal variant(s) presumably influence disease susceptibility via an influence on cis-regulation within the genomic region. We implicated rs7132908 as a putative causal variant at this locus leveraging a combination of our inhouse 3D genomic data, public domain datasets, and several computational approaches. Using a luciferase reporter assay in human primary astrocytes, we observed allele-specific cis-regulatory activity of the immediate region harboring rs7132908. Motivated by this finding, we went on to generate isogenic human embryonic stem cell lines homozygous for either rs7132908 allele with CRISPR-Cas9 homology-directed repair to assess changes in gene expression due to genotype and chromatin accessibility throughout a differentiation to hypothalamic neurons, a key cell type known to regulate feeding behavior. We observed that the rs7132908 obesity risk allele influenced the expression of FAIM2 along with other genes, decreased the proportion of neurons produced during differentiation, up-regulated cell death gene sets, and conversely down-regulated neuron differentiation gene sets. We have therefore functionally validated rs7132908 as a causal obesity variant which temporally regulates nearby effector genes at the ch12q13 locus and influences neurodevelopment and survival.

genetics↗

bioRxiv2023

High density SNP array and reanalysis of genome sequencing uncovers CNVs associated with neurodevelopmental disorders in KOLF2.1J iPSCs

The KOLF2.1J iPSC line was recently proposed as a reference iPSC to promote the standardization of research studies in the stem cell field. Due to overall good performance differentiating to neural cell lineages, high gene editing efficiency, and absence of genetic variants associated to neurological disorders KOLF2.1J iPSC line was particularly recommended for neurodegenerative disease modeling. However, our work uncovers that KOLF2.1J hPSCs carry heterozygous small copy number variants (CNVs) that cause DTNBP1, JARID2 and ASTN2 haploinsufficiencies, all of which are associated with neurological disorders. We further determine that these CNVs arose in vitro over the course of KOLF2.1J iPSC generation from a healthy donor-derived KOLF2 iPSC line and affect the expression of DNTBP1, JARID2 and ASTN2 proteins in KOLF2.1J iPSCs and neural progenitors. Therefore, our study suggests that KOLF2.1J iPSCs carry genetic variants that may be deleterious for neural cell lineages. This data is essential for a careful interpretation of neural cell studies derived from KOLF2.1J iPSCs and highlights the need for a catalogue of iPSC lines that includes a comprehensive genome characterization analysis.

genetics↗

bioRxiv2023

Generation of a human Tropomyosin 1 knockout iPSC line

The CHOPWT17_TPM1KOc28 iPSC line was generated to interrogate the functions of Tropomyosin 1 (TPM1) in primary human cell development. This line was reprogrammed from a previously published wild type control iPSC line.

cell biology↗

bioRxiv2019

Machine learning-based identification and cellular validation of Tropomyosin 1 as a genetic inhibitor of hematopoiesis.

Identifying causal variants and genes from human genetics studies of hematopoietic traits are important to enumerate basic regulatory mechanisms underlying these traits, and could ultimately augment translational efforts to generate platelets and/or red blood cells in vitro. To identify putative causal genes from these data, we performed computational modelling using available genome-wide association data sets for platelet traits. Our model identified a joint collection of genomic features enriched at established platelet trait associations and plausible candidate variants. Additional studies associating variation at these loci with change in gene expression highlighted the Tropomyosin 1 (TPM1) among our top-ranked candidate genes. CRISPR/Cas9-mediated TPM1 knockout in human induced pluripotent stem cells (iPSCs) enhanced hematopoietic progenitor development, increasing total megakaryocyte as well as erythroid cell yields. Our findings may help explain human genetics associations and identify a novel genetic strategy to enhance in vitro hematopoiesis.

genomics↗