2007-12-01 to 2010-12-31 | PhD in Biochemistry
2000-10-01 to 2006-03-31 | Master's Degree in Medical Biotechnologies (Department of Histology, Microbiology and Medical Biotechnologies)
Therapeutic targeting of cellular prion protein: toward the development of dual mechanism anti-prion compounds Antonio Masone, Chiara Zucchelli, Enrico Caruso, Giovanna Musco, Roberto Chiesa Neural Regeneration Research, 2025 PrPSc, a misfolded, aggregation-prone isoform of the cellular prion protein (PrPC), is the infectious prion agent responsible for fatal neurodegenerative diseases of humans and other mammals. PrPSc can adopt different pathogenic conformations (prion strains), which can be resistant to potential drugs, or acquire drug resistance, posing challenges for the development of effective therapies. Since PrPC is the obligate precursor of any prion strain and serves as the mediator of prion neurotoxicity, it represents an attractive therapeutic target for prion diseases. In this minireview, we briefly outline the approaches to target PrPC and discuss our recent identification of Zn(II)-BnPyP, a PrPC-targeting porphyrin with an unprecedented bimodal mechanism of action. We argue that in-depth understanding of the molecular mechanism by which Zn(II)-BnPyP targets PrPC may lead toward the development of a new class of dual mechanism anti-prion compounds.
SP140 represses specific loci by recruiting polycomb repressive complex 2 and NuRD complex Simone Tamburri, Chiara Zucchelli, Vittoria Matafora, Ettore Zapparoli, Zivojin Jevtic, et al. Nucleic Acids Research, 2025 SP140, a lymphocytic-restricted protein, is an epigenetic reader working as a corepressor of genes implicated in inflammation and orchestrating macrophage transcriptional programs to maintain cellular identity. Reduced SP140 expression is associated both to autoimmune diseases and blood cancers. However, the molecular mechanisms that link SP140 altered protein levels to detrimental effects on the immune response and cellular growth, as well as the interactors through which SP140 promotes gene silencing, remain elusive. In this work, we have applied a multi-omics approach (i.e. interactomics, ChIP-seq and proteomics) in two Burkitt lymphoma cell lines to identify both interactors and target genes of endogenous SP140. We found that SP140 interacts with the PRC2 and NuRD complexes, and we showed that these interactions are functional as SP140 directs H3K27me3 deposition and NuRD binding on a set of target genes implicated in cellular growth and leukemia progression.
The C-terminal PHDVC5HCH tandem domain of NSD2 is a combinatorial reader of unmodified H3K4 and tri-methylated H3K27 that regulates transcription of cell adhesion genes in multiple myeloma A. Berardi, C. Kaestner, Michela Ghitti, G. Quilici, Paolo Cocomazzi, et al. Nucleic Acids Research, 2025 Histone methyltransferase NSD2 (MMSET) overexpression in multiple myeloma (MM) patients plays an important role in the development of this disease subtype. Through the expansion of transcriptional activating H3K36me2 and the suppression of repressive H3K27me3 marks, NSD2 activates an aberrant set of genes that contribute to myeloma growth, adhesive and invasive activities. NSD2 transcriptional activity also depends on its non-catalytic domains, which facilitate its recruitment to chromatin through histone binding. In this study, using NMR, ITC and molecular dynamics simulations, we show that the tandem PHD domain of NSD2 (PHDVC5HCHNSD2) is a combinatorial reader of unmodified histone H3K4 and tri-methylated H3K27 (H3K27me3). This is the first PHD tandem cassette known to decode the methylation status of H3K27. Importantly, in a NSD2-dependent MM cellular model, we show that expression of NSD2 mutants, engineered to disrupt the interaction between H3K27me3 and PHDVC5HCH, display in comparison to wild-type NSD2: incomplete loss of H3K27 methylation throughout the genome, decreased activation of adhesive properties and cell adhesion genes, and a decrease of the corresponding H3K27ac signal at promoters. Collectively, these data suggest that the PHDVC5HCH domain of NSD2 plays an important role in modulating gene expression and chromatin modification, providing new opportunities for pharmacological intervention.
The acidic intrinsically disordered region of the inflammatory mediator HMGB1 mediates fuzzy interactions with CXCL12 Malisa Vittoria Mantonico, Federica De Leo, Giacomo Quilici, Liam Sean Colley, Francesco De Marchis, et al. Nature Communications, 2024 Chemokine heterodimers activate or dampen their cognate receptors during inflammation. The CXCL12 chemokine forms with the fully reduced (fr) alarmin HMGB1 a physiologically relevant heterocomplex (frHMGB1•CXCL12) that synergically promotes the inflammatory response elicited by the G-protein coupled receptor CXCR4. The molecular details of complex formation were still elusive. Here we show by an integrated structural approach that frHMGB1•CXCL12 is a fuzzy heterocomplex. Unlike previous assumptions, frHMGB1 and CXCL12 form a dynamic equimolar assembly, with structured and unstructured frHMGB1 regions recognizing the CXCL12 dimerization surface. We uncover an unexpected role of the acidic intrinsically disordered region (IDR) of HMGB1 in heterocomplex formation and its binding to CXCR4 on the cell surface. Our work shows that the interaction of frHMGB1 with CXCL12 diverges from the classical rigid heterophilic chemokines dimerization. Simultaneous interference with multiple interactions within frHMGB1•CXCL12 might offer pharmacological strategies against inflammatory conditions.
Mechanism of action of the tumor vessel targeting agent NGR-hTNF: Role of both NGR peptide and hTNF in cell binding and signaling Barbara Valentinis, Simona Porcellini, Claudia Asperti, Manuela Cota, Dan Zhou, et al. International Journal of Molecular Sciences, 2019 NGR-hTNF is a therapeutic agent for a solid tumor that specifically targets angiogenic tumor blood vessels, through the NGR motif. Its activity has been assessed in several clinical studies encompassing tumors of different histological types. The drug’s activity is based on an improved permeabilization of newly formed tumor vasculature, which favors intratumor penetration of chemotherapeutic agents and leukocyte trafficking. This work investigated the binding and the signaling properties of the NGR-hTNF, to elucidate its mechanism of action. The crystal structure of NGR-hTNF and modeling of its interaction with TNFR suggested that the NGR region is available for binding to a specific receptor. Using 2D TR-NOESY experiments, this study confirmed that the NGR-peptides binds to a specific CD13 isoform, whose expression is restricted to tumor vasculature cells, and to some tumor cell lines. The interaction between hTNF or NGR-hTNF with immobilized TNFRs showed similar kinetic parameters, whereas the competition experiments performed on the cells expressing both TNFR and CD13 showed that NGR-hTNF had a higher binding affinity than hTNF. The analysis of the NGR-hTNF-triggered signal transduction events showed a specific impairment in the activation of pro-survival pathways (Ras, Erk and Akt), compared to hTNF. Since a signaling pattern identical to NGR-hTNF was obtained with hTNF and NGR-sequence given as distinct molecules, the inhibition observed on the survival pathways was presumably due to a direct effect of the NGR-CD13 engagement on the TNFR signaling pathway. The reduced activation of the pro survival pathways induced by NGR-hTNF correlated with the increased caspases activation and reduced cell survival. This study demonstrates that the binding of the NGR-motif to CD13 determines not only the homing of NGR-hTNF to tumor vessels, but also the increase in its antiangiogenic activity.
