Biology subjects

D'Angelo, A.

Publications and source records attributed to D'Angelo, A..

6 recordsLinked to original sources

bioRxiv2026

Neuronal late endosomes serve as selective RNA hubs disrupted by ALS-linked FUS mutation

Neurons depend on tightly regulated positioning of cellular components to maintain long-distance signaling, but the mechanisms guiding specific mRNAs to distant regions remain unclear. Here we show that late endosomes function as selective RNA carriers in human motor neurons and uncover the molecular logic guiding their loading. Using APEX2-mediated proximity labeling, we identify the external transcriptome of RAB7A-positive endosomes and find a specific population of mRNAs enriched for endosomal, axonal and synaptic functions. We find that mRNAs enriched in RAB7A endosomes contain evolutionarily conserved 5'UTRs which act as localization signals, and that the RNA-binding protein GEMIN5 interacts with these regions to promote endosomal RNA recruitment. Finally, we show that in ALS-associated conditions there is a conspicuous loss of endosome-associated transcripts and the mislocalization of GEMIN5 from endosomes. These findings uncover fundamental principles of RNA compartmentalization and highlight endosomal mRNA loading as a vulnerable axis in neuronal homeostasis.

molecular biology↗

bioRxiv2025

Mutant FUS perturbs m6A regulation by repressing ALKBH5, while restoring m6A levels alleviates ALS pathology in vivo

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder marked by the progressive loss of motor neurons, where aberrant stress granule (SG) dynamics has emerged as a hallmark, especially in cases involving mutations in RNA-binding proteins such as FUS and TDP-43. We previously showed that m6A RNA modification is elevated in FUS-associated ALS and that restoring its physiological levels through METTL3 inhibition is sufficient to rescue the aberrant stress granule phenotypes in different human cellular models. Importantly, here we show that reducing m6A levels ameliorates locomotor defects and neuromuscular junction (NMJ) abnormalities in Drosophila melanogaster models of ALS expressing the human FUSP525L mutant. Moreover, we demonstrate that the increase in m6A is attributable to reduced expression of the m6A eraser ALKBH5, resulting from impaired translation caused by direct FUS binding to its transcript. We further show that ALKBH5 downregulation contributes to RNA and protein alterations observed in FUS-associated ALS, driving the abnormal SG dynamics characteristic of the disease. This study supports the hypothesis that restoring correct m6A levels could serve as a potential therapeutic strategy for ALS.

molecular biology↗

bioRxiv2025

3D Mapping of Intact Ovaries Reveals the Aging Dynamics of the Ovarian Reserve

Female fertility depends on a finite pool of oocytes that depletes during aging, yet the spatiotemporal dynamics of this depletion remain poorly understood. Traditional methods obscure the 3D architecture of the ovary, limiting quantitative insights. Here, we combine light-sheet microscopy, artificial intelligence (AI)-driven segmentation, and mathematical modeling to map over 85,000 oocytes in whole-ovaries across the reproductive lifespan in mouse. We find that newly activated oocytes represent a fixed fraction of the ovarian reserve, despite an age-related decline in total oocyte numbers. Spatial analysis revealed that oocytes are enriched along the lateral ovarian axis, and local oocyte density positively correlates with activation. We also uncover a bimodal distribution of oocyte sizes, suggesting a bottleneck during oogenesis. Finally, a differential equation-based model captures the kinetics of oocyte activation and loss. Our findings establish a quantitative framework for understanding ovarian aging and suggest that an organ-scale regulatory mechanism coordinates the age-related decline in oocyte numbers.

cell biology↗

bioRxiv2025

Electrical stimulation elicits space- and parameter-dependent spiking responses in human cortical organoids

Electrical stimulation (ES) is used to treat neuropsychiatric disorders and investigate brain dynamics, yet its effects on human cortical microcircuits remain poorly understood. Cortical organoids provide a unique platform to investigate these mechanisms in isolation from subcortical and long-range cortical inputs. Here we illustrate how cortical organoids respond to ES, identifying the response profiles of isolated cortical circuits while detailing a roadmap of how ES parameters affect the organoid spiking activity. We employed a high-density multielectrode array to record neuronal activity from cortical organoids (n=417 units in N=7 organoids) during ES, systematically varying stimulation frequency, intensity, pulse width, and charge density. By analyzing single unit spiking activity, we found that ES elicits excitatory, inhibitory, and mixed responses in 39%, 12%, and 17% of the units, respectively. On average, this response lasted 100 ms and became stable within 26 trials. The magnitude of both excitatory and inhibitory responses was maximal near the stimulation site and decayed with distance. The response magnitude was inversely correlated with pulse intensity and duration, but not with stimulation frequency and charge density. These findings demonstrate that local cortical circuits are sufficient to initiate the early excitatory phase of the canonical ES response, whose magnitude depends on ES parameters, and can sustain the excitatory phase for over 100 ms. The reduced late inhibitory phase, together with the absence of late excitatory components observed 200 ms after ES in intact adult brains in-vivo, suggests that these phases may depend on neuronal maturation or inter-area connections. Our work thus establishes cortical organoids as a framework for studying the local contributions to ES-induced activity in a developmental model of the human cortex.

neuroscience↗

bioRxiv2025

Targeted Antisense Oligonucleotide Treatment Rescues Developmental Alterations in Spinal Muscular Atrophy Organoids

Spinal muscular atrophy (SMA) is a severe neurological disease caused by mutations in the SMN1 gene, characterized by early onset and degeneration of lower motor neurons. Understanding early neurodevelopmental defects in SMA is crucial for optimizing therapeutic interventions. Using spinal cord and cerebral organoids generated from multiple SMA type I donors, we revealed widespread disease mechanisms beyond motor neuron degeneration. Single-cell transcriptomics uncovered pervasive alterations across neural populations, from progenitors to neurons, demonstrating SMN-dependent dysregulation of neuronal differentiation programs. Multi-electrode array analysis identified consistent hyperexcitability in both spinal and brain organoids, establishing altered electrical properties as a central nervous system-wide feature of pathogenesis. Early administration of an optimized antisense oligonucleotide (ASO) that restored SMN levels rescued morphological and functional deficits in spinal cord organoids across different genetic backgrounds. Importantly, this early intervention precisely corrected aberrant splicing in newly identified SMN1 targets enriched at critical nodes of neuronal differentiation. Our findings demonstrate that early developmental defects are core features of SMA pathogenesis that can be prevented by timely therapeutic intervention, providing new insights for optimizing treatment strategies.

neuroscience↗

bioRxiv2017

Probing tissue-scale deformation by in vivo force application reveals a fast tissue softening during early embryogenesis

During development, cell-generated forces induce tissue-scale deformations to shape the organism. Here, we present a method that allows to quantitatively relate such tissue-scale deformations to spatially localized forces and measure mechanical properties of epithelia in vivo. Our approach is based on the application of controlled forces on microparticles embedded in individual cells of an embryo. Combining measurements of the bead displacement with the analysis of induced deformation fields in a continuum mechanics framework, we can quantify tissue material properties and follow their change over time. In particular, we uncover a rapid change in tissue response occurring during Drosophila cellularization, resulting from a softening of the blastoderm and an increase of external friction. Pharmacological treatments reveal that in addition to actomyosin, the microtubule cytoskeleton is a major contributor to epithelial mechanics at that stage. Overall, our method allows for measuring essential mechanical parameters governing tissue-scale deformations and flows occurring during morphogenesis.

bioinformatics↗