Biology subjects

Fusco, C.

Publications and source records attributed to Fusco, C..

3 recordsLinked to original sources

bioRxiv2026

Epigenetic signature at FOXP3 distal enhancer affects regulatory T cell development in Kabuki syndrome

Kabuki syndrome (KS) is a congenital developmental disorder caused by germinal pathogenic variants in the lysine methyltransferase 2D (KMT2D, KS1) or lysine demethylase 6A (KDM6A, KS2) genes. Kabuki patients display mental retardation, multiorgan malformations and immune dysregulation - ranging from immunodeficiency to autoimmunity - which strongly compromises their life expectancy. We explored whether the complex immunological scenario of Kabuki syndrome 1 subjects (Ks) could be ascribed to an altered generation of CD4+FOXP3+ regulatory T cells (Tregs). We report that pediatric Ks carrying KMT2D pathogenic variants show a significant reduction of Tregs. DNA methylation analysis reveals a specific methylation pattern at the FOXP3 distal enhancer that correlates with decreased FOXP3 transcription early during Treg cell induction and promotes T helper (Th)-2 lineage differentiation. Finally, in vitro T cell demethylation rescues FOXP3 expression and Treg induction in Ks, offering a novel potential therapeutic perspective. Our findings connect KMT2D loss-of-function to the inhibition of human FOXP3 gene transcription and provide novel molecular insights to explain the immunological phenotype in Ks, thus pinpointing this syndrome as a novel Tregopathy.

immunology↗

bioRxiv2026

Comprehensive classification of HCN1 variants linked to neurodevelopmental disorders with and without epilepsy

Hyperpolarization-activated cyclic nucleotide-gated 1 channels (HCN1) mediate the Ih cationic current and play a central role in regulating neuronal excitability and synaptic integration. HCN1 is predominantly expressed in the neocortex and hippocampus. Pathogenic variants in HCN1 have been increasingly identified in individuals presenting with a broad spectrum of epileptic disorders, ranging from severe developmental and epileptic encephalopathy (DEE) to milder epilepsies. Here, we used patch-clamp electrophysiology in combination with confocal imaging in HEK293 cells to functionally characterize 43 HCN1 variants found in patients presenting with neurodevelopmental disorders, with or without epilepsy. Based on their biophysical properties, we defined four functional classes: (I) low or no current, (II) hyperpolarizing (i.e. left) shift in voltage dependence, (III) depolarizing (i.e. right) shift in voltage dependence, and (IV) generation of an instantaneous current. Integration of this functional classification with detailed clinical data from a cohort of 49 patients revealed a striking genotype-phenotype correlation. Loss-of-function variants were strongly enriched among individuals without epilepsy or with milder generalized phenotypes, whereas gain-of-function and mixed variants were predominantly associated with epilepsy, including all cases of DEE. Notably, non-epileptic cases clustered within a subgroup of loss-of-function variants affecting the selectivity filter. We further show that allosteric modulators, including the peptides NB6 and TRIP8bnano and the small molecule J&J12e, normalize the functional properties of mutant HCN1 channels in three classes. These findings establish a clinically relevant framework for interpreting HCN1 gain- and loss-of-function variants suggesting that the direction of channel dysfunction is a major determinant of epilepsy risk and severity.

pathology↗

bioRxiv2024

CD4+Foxp3E2+ regulatory T cell frequency predicts breast cancer prognosis and recurrence

CD4+Foxp3+ regulatory T cells (Tregs) are key to maintain peripheral self-tolerance and suppress immune responses to tumors. Their accumulation in the tumor microenvironment (TME) correlates with poor clinical outcome in several human cancers, including breast cancer (BC). However, the properties of intratumoral Tregs remain largely unknown. Here, we found that a functionally distinct subpopulation of tumor-infiltrating Tregs, which express the Foxp3 splicing variant retaining exon 2 (Foxp3E2), is prominent in the TME and peripheral blood of hormone receptor- positive (HR+) BC subjects with poor prognosis. Notably, a comprehensive examination of the Tumor Cell Genome Atlas (TCGA) validated Foxp3E2 as an independent prognostic marker in all other BC subtypes. We found that FOXP3E2 expression underlies BCs with highly immune suppressive landscape, defective mismatch repair and a stem-like signature thus highlighting pathways involved in tumor immune evasion. Finally, we confirmed the higher immunosuppressive capacity of BC patients-derived Foxp3E2+ Tregs by functional assays. Our study suggests Foxp3E2+ Tregs might be used as an independent biomarker to predict BC prognosis and recurrence, and to develop super-targeted depletion-based immunotherapies. One-sentence summariesFoxp3E2+ Treg enrichment reflects an increased tumor-immune suppression and predicts prognosis and recurrence in breast cancer.

immunology↗