Genomic and functional study of Cornelia de Lange syndrome in iPSC-derived cellular models - STUDI GENOMICI E FUNZIONALI SULLA SINDROME DI CORNELIA DE LANGE BASATI SULL’UTILIZZO DI COLTURE DI CELLULE IPSC (INDUCED PLURIPOTENT STEM CELLS)

Cornelia de Lange Syndrome (CdLS) is a multisystem genetic disorder characterized by craniofacial abnormalities, limb malformations, growth retardation, intellectual disability, and developmental delay. This syndrome belongs to the group of cohesinopathies, as it is caused by mutations in genes encoding components of the cohesin complex, which plays a crucial role in regulating gene expression and chromatin organization. Due to the associated disruption of chromatin structure, CdLS is also classified among chromatinopathies. Alterations in chromatin organization have recently been recognized as key contributors to the pathogenesis of myeloid neoplasms, a group of clonal disorders of hematopoietic stem cells caused by mutations in genes involved in transcriptional regulation, epigenetic control, and RNA splicing. In particular, mutations affecting components of the cohesin complex (such as STAG2, RAD21, SMC1A, SMC3, and PDS5B) and its regulatory proteins (including NIPBL, MAU2, and HDAC8) play a critical role in hematopoietic stem cell function. These mutations are found in approximately 20% of patients with acute myeloid leukemia (AML), often in association with mutations in other genes such as NPM1 (Nucleophosmin), FLT3 (FMS-like tyrosine kinase), RUNX1 (Runt-related transcription factor 1), and ASXL1 (Additonal sex-combs-like). In light of the link between cohesin dysfunction, chromatin disorganization, and leukemogenesis, the present study aims to establish an in vitro differentiation system of induced pluripotent stem cells (iPSCs) along the myeloid hematopoietic lineage using this model of chromatinopathy. To this end, iPSC lines derived from CdLS patients was used alongside control iPSC lines obtained from healthy individuals. These cell lines were generated and available at the Laboratory of Molecular Biology of the Mario Negri Institute for Pharmacological Research. The objective of this work is to establish an in vitro differentiation system based on iPSC to understand the pathogenic mechanisms underlying CdLS. In particular, the final goal of the project is focused on the role of cohesin and chromatin alterations in leukemic transformation.

La sindrome di Cornelia de Lange (Cornelia de Lange Syndrome = CdLS) è una rara malattia dello sviluppo che interessa prevalentemente la popolazione pediatrica. La CdLS appartiene alla famiglia delle “coesinopatie” germinali causate da mutazioni aplo-insufficienti di diversi geni codificanti proteine appartenenti al complesso della coesina (SMC1A, SMC3, RAD21, STAG, PDS5 and WAPL) o proteine regolatorie del complesso stesso (NIPBL, MAU2 and HDAC8). Le alterazioni dell’organizzazione della cromatina sono state recentemente riconosciute come fattori chiave nella patogenesi delle neoplasie mieloidi. In particolare, mutazioni dei geni codificanti membri del complesso della coesinasono fortemente e direttamente correlate allo sviluppo di diversi tipi di leucemia mieloide acuta. In considerazione del fatto che le leucemie mieloidi sono la conseguenza di anomalie nei processi di differenziazione delle cellule neoplastiche, la tesi si focalizza sul differenziamento ematopoietico mieloide delle cellule iPSC derivate da una paziente affetta daCdLS. L’obiettivo principale della tesi è mettere a punto un sistema in vitro basato su colture di cellule iPSC indotte a differenziarsi verso cellule di tipo monocitario/macrofagico. A lungo termine, la tesi si propone di identificare geni ecorrispondenti proteine che possano rappresentare bersagli farmacologici nell’ambito del trattamento personalizzato della CdLS e del miglioramento della qualità di vita dei pazienti affetti da questa patologia.