Biology subjects

Amilibia, E.

Publications and source records attributed to Amilibia, E..

5 recordsLinked to original sources

bioRxiv2026

VESTIBULAR FUNCTION LOSS ASSOCIATES WITH SENSORY EPITHELIUM PATHOLOGY IN VESTIBULAR SCHWANNOMA PATIENTS

Vestibular schwannomas (VS) cause vestibular function loss by mechanisms still poorly understood. We evaluated the vestibulo-ocular reflex by the video-assisted Head Impulse Test (vHIT) in patients with planned tumour resection by a trans-labyrinthine approach. The vestibular sensory epithelia were collected and processed by immunofluorescent labelling for confocal microscopy analysis of sensory hair cell subtypes (type I, HCI, and type II, HCII), calyx endings of the pure-calyx afferents, and the calyceal junction normally found between HCI and the calyx (n=23). Comparing Normo-vHIT and Hypo-vHIT patients, we concluded that worse vestibular function associates with decreased HCI and HCII counts in the sensory epithelia and with increased proportion of damaged calyces. A decrease in the number of HCI and calyx endings of the pure-calyx afferents was recorded to associate with age increase. Partial least squares regression (PLSR) models indicated that VS and age had independent, additive effects on vestibular function. Correlation analyses indicated that lower vHIT gains associate with lower numbers of HCI and increased percentages of damaged calyces. These data support the hypothesis that the deleterious effect of VS on vestibular function is mediated, at least in part, by its damaging impact on the vestibular sensory epithelium. They also provide further evidence for the dependency of the vestibulo-ocular reflex on HCI function and for the calyceal junction pathology as a common response of the sensory epithelium to HC stress.

neuroscience↗

bioRxiv2025

Three-Dimensional Epigenome Roadmap of Human B-cell Differentiation Uncovers Mechanisms of Humoral Immunity and Oncogenesis

Human B-cell differentiation underlies humoral immunity, and its disruption leads to cancer, autoimmunity, and immunodeficiencies. However, the enhancer-based regulatory mechanisms governing this process remain poorly understood. To address this gap, we generated the first three-dimensional epigenomic roadmap of human B-cell differentiation in vivo. By profiling nine differentiation stages, we linked nearly half a million enhancers to their target genes through chromatin interactions, defined their activity states, and predicted bound transcription factors. We show that the acquisition of B-cell identity, distinct from common cellular processes, relies on large enhancer networks acting additively and synergistically to finely tune transcription. We further identify a 3D epigenetic priming mechanism underlying immune memory, whereby memory B cells retain primed DNA loops that enable faster responses to antigen re-exposure. Extending this roadmap to disease, we demonstrate that B-cell malignancies preserve enhancer signatures of their cell of origin while silencing distal tumor suppressor control. Finally, we uncover a previously unappreciated oncogenic mechanism in which intragenic deletions disrupt distal gene regulation via enhancer loss. Together, this resource provides a framework for understanding the genetic and epigenetic basis of humoral immunity and immune-related diseases.

genomics↗

bioRxiv2025

NF2 lacking exon 11 isoform induced by antisense gene therapy is able to recover partially merlin deficiency on NF2-related Schwannomatosis iPSC-derived spheroid model

NF2-related Schwannomatosis (NF2-SWN) is an inherited autosomal dominant disorder resulting from loss-of-function mutations in the NF2 gene, for which no effective treatment is currently available. Furthermore, truncating variants in NF2 are associated with the severest phenotype compared to in-frame or missense variants. Previously, a shorter NF2 isoform with exon 11 skipped (merlin_e-11), induced through antisense morpholino oligomers (PMOs), was able to partially rescue the deleterious effect of nonsense variants located at that exon in patients primary fibroblast. To test the potential of this approach into Schwann cells, those responsible of NF2-SWN tumours, we developed an iPSC-based model carrying heterozygous and homozygous truncating variants on exon 11 of the NF2 gene and differentiated them to Schwann cells forming spheroids. After 3 days of treatment, merlin_e-11 expression was induced in NF2-deficient cell lines. Furthermore, key pathways associated with NF2-deficiency in schwannomas, such as PI3K/Akt/mTORC and YAP levels, were recovered without signs of toxicity. These results confirm that the PMO treatment induces effective skipping of exon 11 in Schwann cell spheroids, generating an hypomorphic merlin_e-11 that has the capacity to partially rescue merlin-deficiency in NF2-SWN spheroid cell model and it being a potential treatment of patients harbouring truncating variants located in exon 11.

genetics↗

bioRxiv2022

Merlin-deficient iPSCs show altered pluripotency and constitute a potential in vitro model for NF2-related schwannomas

NF2-related schwannomatosis is an autosomal dominant syndrome that predisposes to the development of benign tumors of the nervous system. Schwannomas, particularly bilateral vestibular schwannomas (VS), are the most characteristic features of the disease. These tumors are caused by the bi-allelic inactivation of the NF2 gene in a cell of the Schwann cell lineage. Our current understanding of the molecular pathogenesis of the NF2 gene, as well as the development of new effective therapies is hampered by the absence of human non-perishable cell-based bearing distinct NF2 pathogenic variants. With this aim, we generated and characterized three isogenic paired induced pluripotent stem cell (iPSC) lines with single or bi-allelic inactivation of NF2 by combining the direct reprogramming of VS cells with the use of CRISPR/Cas9 editing. Our results show a critical function of NF2 for the maintenance of a stable pluripotent state. However, we were able to nudge them towards the Neural Crest-Schwann Cell (NC-SC) axis by applying a 3D Schwann cell differentiation protocol. NF2(+/-) and NF2(-/-) spheroids homogeneously expressed classical markers of the NC-SC lineage. In addition, NF2(-/-) SC-like spheroids showed dysregulation of multiple signaling pathways already described for merlin-deficient SC, and altered in human schwannomas. Therefore, NF2(+/-) and NF2(-/-) SC-like spheroids can represent a bona fide human in vitro cellular model to study the role of NF2 pathogenesis.

cell biology↗

bioRxiv2022

The vestibular calyceal junction is dismantled in response to diverse injuring stimuli in rats and humans

Hair cell (HC) loss by epithelial extrusion has been described to occur in the rodent vestibular system during chronic 3,3-iminodipropionitrile (IDPN) ototoxicity. This is preceded by dismantlement of the calyceal junction in the contact between type I HC (HCI) and calyx afferent terminals. Here, we evaluated whether these phenomena have wider significance. First, we studied rats receiving streptomycin for 3 to 8 weeks. Streptomycin caused loss of vestibular function associated with partial loss of HCI and decreased expression of contactin-associated protein (CASPR1), denoting calyceal junction dismantlement, in the calyces encasing the surviving HCI. Additional molecular and ultrastructural data supported the conclusion that HC-calyx detachment precede HCI loss by extrusion. Animals allowed to survive after the treatment showed functional recuperation and rebuilding of the calyceal junction. Second, we evaluated human sensory epithelia obtained during therapeutic labyrinthectomies and trans-labyrinthine tumour excisions. Some samples showed abnormal CASPR1 label strongly suggestive of calyceal junction dismantlement. Therefore, reversible dismantlement of the vestibular calyceal junction may be a common response triggered by chronic stress, including ototoxic stress, before HCI loss. This may partly explain clinical observations of reversion in function loss after aminoglycoside exposure.

neuroscience↗