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Biology subjects

Corneo, B.

Publications and source records attributed to Corneo, B..

4 recordsLinked to original sources

Cyclin C nuclear release and mitochondrial dysfunction define molecular signatures of MED13L Syndrome

The Mediator Kinase Module (MKM) coordinates transcriptional programs regulating cellular metabolism, stress responses, and differentiation. Heterozygous variants of MED13L, a core MKM component, cause a neurodevelopmental disorder characterized by variable intellectual disability, developmental delay, neuromuscular dysfunction, and congenital anomalies. However, the molecular basis underlying this clinical heterogeneity is poorly defined. Previously, we identified mitochondrial dysfunction and aberrant nuclear release of another MKM component, cyclin C (CCNC), in a single MED13L syndrome patient-derived fibroblast line. Here, we expand these studies across 12 patient-derived fibroblasts harboring 11 distinct MED13L variants. We identify mitochondrial dysfunction as a consistent feature of MED13L variation, characterized by reduced mitochondrial ATP production, decreased mitochondrial DNA abundance, elevated reactive oxygen species, and impaired transcription of genes involved in mitochondrial biogenesis. In parallel, all variant lines exhibit aberrant cytoplasmic CCNC localization, consistent with its established role in mitochondrial fission. Longitudinal analyses further reveal progressive declines in mitochondrial function associated with premature cellular aging, consistent with increased metabolic deficits. Importantly, the severity of mitochondrial dysfunction shows an association with variant position within MED13L and with clinical functional measures, suggesting that mutation location may partially predict disease severity. Together, these findings establish mitochondrial dysfunction as a consistent cellular feature of MED13L heterozygosity and identify CCNC mis-localization as a candidate biomarker of MKM disruption. More broadly, this work reveals an intersection between transcriptional control and mitochondrial homeostasis in MED13L syndrome, forming the framework for biomarker-driven therapeutic development in MED13L-associated and related neurodevelopmental disorders.

genetics↗

Derivation and analysis of human somatic sensory neuron subtypes facilitated through fluorescent hPSC reporters

Peripheral sensory neuropathy (PSN) is associated with several devastating neurological conditions, yet effective strategies to prevent or alleviate the consequences of PSN are nearly non-existent. A major challenge in the development of better therapeutic interventions is the lack of appropriate human model systems. Human induced pluripotent stem cell (hiPSC)-derived somatosensory neurons present a promising strategy to overcome this issue but remain of limited translational utility, in part due to the low efficiency and lack of sensory subtype selectivity of the existing sensory neuron derivation protocols. To improve upon iPSC-based somatosensory disease models, we here describe the generation and validation of a genetic toolset to fluorescently label all or distinct (nociceptor, low threshold mechanoreceptor, and proprioceptor) somatosensory subtypes. These new resources will be transformative for hPSC-based approaches in PSN disease modeling - a critical step towards translating new findings into clinically relevant therapeutic strategies.

neuroscience↗

iPSC-based modeling of helicase deficiency reveals impaired cell proliferation and increased apoptosis after NK cell lineage commitment

While monogenic variants in CDC45-MCM-GINS (CMG) replisome proteins cause human natural killer cell deficiencies (NKD), family members with the same inherited variants often have variable clinical and cellular phenotypes. We investigated two siblings with inherited compound heterozygous GINS4 variants but variable disease expressivity. Cell cycle impairment and increased apoptosis were detected following NK cell lineage commitment but not in pluripotent cells. While this effect was detected in both siblings, the efficiency of NK cell differentiation was variable and correlated with differential clinical severity of NKD. Further investigation of allelic expression of inherited GINS4 variants demonstrated expected biallelic expression of GINS4 in pluripotent cells and progenitors. However, allelic bias in lineage-committed NK cells led to over- or under-representation of more damaging GINS4 heterozygous variants associated with differential cellular and clinical severity. This study identifies allelic bias that causes phenotypic variation of monogenic diseases and defines mechanisms underlying immunodeficiency.

cell biology↗

Cortical Overgrowth in a Preclinical Forebrain Organoid Model of CNTNAP2-Associated Autism Spectrum Disorder

Autism spectrum disorder (ASD) represents a major public health burden but translating promising treatment findings from preclinical non-human models of ASD to the clinic has remained challenging. The recent development of forebrain organoids generated from human induced pluripotent stem cells (hiPSCs) derived from subjects with brain disorders is a promising method to study human-specific neurobiology, and may facilitate the development of novel therapeutics.\n\nIn this study, we utilized forebrain organoids generated from hiPSCs derived from patients from the Old Order Amish community with a rare syndromic form of ASD, carrying a homozygous c.3709DelG mutation in CNTNAP2 and healthy controls to investigate the effects of this mutation on cortical embryonic development.\n\nPatients carrying the c.3709DelG mutation in CNTNAP2 present with an increased head circumference and brain MRI reveals an increase in gray matter volume. Patient-derived organoids displayed an increase in total volume that was driven by an increased proliferation in neural progenitor cells, leading to an increase in the generation of cortical neuronal and non-neuronal cell types. The observed phenotypes were rescued after correction of the pathogenic mutation using CRISPR-Cas9. RNA sequencing revealed 339 genes differentially expressed between patient- and control-derived organoids of which a subset are implicated in cell proliferation and neurogenesis. Notably, these differentially expressed genes included previously identified ASD-associated genes and are enriched for genes in ASD-associated weighted gene co-expression networks.\n\nThis work provides a critical step towards understanding the role of CNTNAP2 in human cortical development and has important mechanistic implications for ASD associated with brain overgrowth. This CNTNAP2 organoid model provides opportunity for further mechanistic inquiry and development of new therapeutic strategies for ASD.

neuroscience↗