Biology subjects

Colamatteo, A.

Publications and source records attributed to Colamatteo, A..

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↗

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↗

bioRxiv2020

PD-1-induced T cell exhaustion is controlled by a Drp1-dependent mechanism

PD-1 signalling downregulates the T cell response, promoting an exhausted state in tumor-infiltrating T cells, through mostly unveiled molecular mechanisms. Drp1-dependent mitochondrial fission plays a crucial role to sustain T cell motility, proliferation, survival and glycolytic engagement and, interestingly, such processes are exactly those inhibited by PD-1 in tumor-infiltrating T cells. Here we show that the signature of PD-1pos CD8+ T cells infiltrating MC38-derived murine tumor mass is having downregulated Drp1 activity and more fused mitochondria, compared to PD-1neg counterparts. Also, PD-1pos lymphocytic elements infiltrating human colon cancer rarely express active Drp1. Mechanistically, PD-1 signalling directly prevents mitochondria fragmentation following T cell stimulation by downregulating Drp1 phosphorylation on Ser616, via regulation of the ERK1/2 and mTOR pathways. In addition, downregulation of Drp1 activity in tumor-infiltrating PD-1pos CD8+ T cells seems to be a mechanism exploited by PD-1 signalling to reduce motility and proliferation of these cells. Overall, our data indicate that the modulation of Drp1 activity in tumor-infiltrating T cells may become a valuable target to ameliorate the anti-cancer immune response in future immunotherapy approaches.

immunology↗