Biology subjects

Palandri, A.

Publications and source records attributed to Palandri, A..

4 recordsLinked to original sources

bioRxiv2026

Disruption of Myelin-Associated Glycoprotein Activity Drives Aberrant Cerebellar Neurodevelopment and Autism-Like Behaviors.

Immune-mediated mechanisms have emerged as important contributors to neurodevelopmental vulnerability in a subset of autism spectrum disorder (ASD) cases. Circulating IgG antibodies against myelin-associated glycoprotein (MAG) have been reported in individuals with ASD and their mothers; however, the pathogenic relevance of these antibodies and the contribution of MAG signaling to neurodevelopment remain unclear. Here, we investigated whether disruption of MAG function during early postnatal life is sufficient to alter cerebellar development and induce ASD-relevant behavioral alterations. Using complementary genetic and immunological approaches, we show that constitutive deletion of Mag or transient postnatal blockade with a function-blocking anti-MAG antibody induces region-specific alterations in cerebellar development. MAG disruption results in excessive proliferation of granule cell precursors followed by delayed, region-restricted neuronal death, together with persistent abnormalities in Purkinje neuron number and dendritic maturation. These structural changes occur in the absence of major or persistent demyelination, consistent with dysregulation of myelin-associated developmental signaling rather than myelin loss. Importantly, early postnatal passive immunization with anti-MAG IgG is sufficient to induce significant impairments in social communication, sociability, and social recognition, recapitulating core behavioral domains relevant to ASD. Together, these data provide experimental evidence that immune-mediated interference with a myelin-associated signaling molecule can disrupt cerebellar development during critical postnatal windows and produce long-lasting behavioral consequences. Our findings identify MAG as a previously underappreciated regulator of neurodevelopment and support a model in which antibody-mediated perturbation of myelin-derived instructive signaling contributes to ASD-relevant phenotypes, aligning with emerging frameworks of immune-linked neurodevelopmental vulnerability. HighlightsO_LIDisruption of myelin-associated glycoprotein (MAG) activity during early postnatal life alters cerebellar development in a region-specific manner. C_LIO_LIGenetic deletion or antibody-mediated blockade of MAG function induces granule cell dysregulation and Pkn structural abnormalities without overt demyelination. C_LIO_LIPassive immunization of anti-MAG antibodies is sufficient to induce autism-like behavioral phenotypes, supporting a causal immune-mediated mechanism. C_LIO_LIThese findings identify myelin-associated signaling as a novel contributor to neurodevelopmental dysfunction and align with the maternal autoantibody-related ASD framework. C_LI

neuroscience↗

bioRxiv2026

An aPKC rheostat induces apical contraction in response to epithelial stretching

Apical-basal polarity in epithelial cells is controlled by a conserved set of polarity factors that define the apical, junctional and basolateral domains of the cell, but how these factors adapt to or control changes in domain sizes during cell shape changes remains unclear. Atypical protein kinase C (aPKC) is the main effector of apical identity, phosphorylating the lateral factors, Bazooka/Par-3, Lgl, Par-1 and Yurt to exclude them from the apical domain. Using analogue-sensitive aPKC in Drosophila follicle cells, we found that aPKC substrates differ over 100-fold in their sensitivity to inhibition, revealing a hierarchy of substrates, that is conserved in mammals, in which high-affinity substrates out-compete low-affinity substrates when aPKC activity is limiting. Mild aPKC inhibition prevents the phosphorylation of its lowest affinity substrate, Yurt. Yurt then accumulates apically by binding to Crumbs, where it activates apical constriction through Shroom, Cysts/Dp114RhoGEF, Rho kinase and Myosin. Yurt localises apically in cells that are stretched, either by morphogenesis or artificially, indicating that stretching reduces aPKC activity to trigger an antagonistic contraction. By contrast, yurt- cells fail to resist stretching. Thus, the aPKC/Yurt pathway functions as a homeostatic stretch response, in which apical and lateral epithelial polarity factors collaborate to mechanically regulate apical domain size.

cell biology↗

bioRxiv2025

Spatio-temporal control of nuclear mechanotransduction during EMT

During epithelial-to-mesenchymal transition (EMT), cells generate mechanical forces. How the nucleus reacts to these mechanical cues, ensuring a tight balance between mechano-protection and mechanotransduction, is a key yet unresolved question. Here we dissect the spatio-temporal control of nuclear mechanostransduction during EMT, using Drosophila mesoderm invagination as a model. We found that two conserved pro-EMT genes respond differently to compressive forces: while snail transcription remains unaffected, compression is sufficient to activate twist transcription within seconds. We further revealed a spatially patterned genome-wide transcriptional response to EMT forces, with an apical mechanoprotection contrasting with a permissive basal nuclear environment. The direct recording of nascent transcription in response to a controlled nuclear micromanipulation provides compelling evidence of nuclear heterogeneity in the transcriptional response to forces. Overall, these results reveal that EMT nuclei respond directly and rapidly to mechanical forces, in a spatially defined pattern.

cell biology↗

bioRxiv2021

A method for single molecule localization microscopy of tissues reveals nonrandom distribution of nuclear pores in Drosophila

Single Molecule Localisation Microscopy (SMLM) can provide nanoscale resolution in thin samples but has rarely been applied to tissues, because of high background from out of focus emitters. Here we describe a line scanning microscope that provides optical sectioning for SMLM in tissues. Imaging endogenously-tagged nucleoporins and F-actin on this system using DNA- and peptide-PAINT routinely gives 30nm resolution or better at depths greater than 20 {micro}m. This revealed that the nuclear pores are nonrandomly distributed in most Drosophila tissues, in contrast to cultured cells. Lamin Dm0 shows a complementary localisation to the nuclear pores, suggesting that it corrals the pores. Furthermore, ectopic expression of the tissue-specific Lamin C distributes the nuclear pores more randomly, whereas lamin C mutants enhance nuclear pore clustering, particularly in muscle nuclei. Since nucleoporins interact with specific chromatin domains, nuclear pore clustering could regulate chromatin organisation locally and contribute to the disease phenotypes caused by human Lamin A/C laminopathies.

cell biology↗