Biology subjects

Mattivi, A.

Publications and source records attributed to Mattivi, A..

5 recordsLinked to original sources

bioRxiv2026

Centrosome architecture and m6A-dependent gating of p53 surveillanceafter whole-genome doubling

Whole-genome doubling (WGD) generates a tetraploid state that challenges cellular homeostasis and is strongly selected against in TP53-proficient contexts. Although centrosome amplification serves as a structural correlate of genome doubling, how centrosomal features engage and sustain p53 surveillance remains incompletely understood. Here, we develop a genetically encoded MDM2-based fluorescent reporter to monitor Caspase-2 pathway activation in living cells after WGD. Combining pharmacological profiling and genome-wide CRISPR screening, we uncover a multi-layered regulation of p53 responses. We identify PLK1-dependent centriole maturation and subdistal appendage integrity as architectural determinants of PIDDosome-dependent Caspase-2 activation, independent of distal appendage assembly. We show that upon WGD, Caspase-2-mediated cleavage of MDM2 reshapes the p53-MDM2 regulatory loop, enabling sustained p53 signaling. This sustained output depends on the catalytic activity of METTL3 and associated m6A writer proteins. Together, these findings demonstrate that centrosome architecture and epitranscriptomic regulation cooperate to shape p53 surveillance after genome doubling. HighlightsO_LIWhole-genome doubling creates a surveillance state sensed by centrosome cluster architecture. C_LIO_LICaspase-2 activation converts the p53-MDM2 loop from negative to positive feedback. C_LIO_LIm6A methylation establishes competence of the p53 module for sustained output. C_LIO_LIA genetically encoded biosensor enables functional dissection of this circuit. C_LI

cell biology↗

bioRxiv2025

Human liver organoids uncover ductular reaction in Wolman disease and inform gene therapy design

Wolman disease (WD), the severe infantile form of lysosomal acid lipase deficiency, is a rare metabolic disorder caused by inactivating mutations in the LIPA gene. Although WD is characterized by profound hepatic dysfunction, experimental human systems capable of modelling multicellular liver pathology and supporting therapeutic testing remain limited. Here, we generated an isogenic human model of WD by introducing LIPA loss-of-function mutations into induced pluripotent stem cells and differentiating them into multicellular human liver organoids (HLO). LIPA-deficient HLO preserved hepatic lineage specification while recapitulating key biochemical and cellular features of WD, including loss of LIPA activity, lysosomal expansion, lipid accumulation, and activation of inflammatory and fibrogenic programs. Single-cell RNA sequencing resolved cell-type-specific disease states across hepatocyte-, stromal-, and biliary-like populations, revealing the emergence of a reactive biliary program consistent with ductular reaction, a complex tissue response associated with chronic liver injury. Importantly, this reactive biliary phenotype was supported by targeted gene-expression analysis in WD liver organoids and independently validated in liver tissue from mouse models and WD patients. Isolated LIPA-deficient cholangiocyte organoids failed to reproduce the DR-associated program, indicating that this response depends on multicellular interactions within the hepatic microenvironment rather than on biliary cell-autonomous dysfunction alone. Consistently, hepatocyte-directed AAV-mediated restoration of LIPA expression attenuated metabolic stress, inflammatory and fibrogenic programs, and suppressed ductular reaction both in organoids and in vivo. Together, these findings establish multicellular human liver organoids as a physiologically relevant platform for modelling emergent tissue-level responses in WD and for evaluating therapeutic rescue strategies in a human context.

pathology↗

bioRxiv2025

A TranSNP in the DDIT4 mRNA can impact its translation efficiency and modulate p53-dependent responses in cancer cells

Relatively few studies have examined the link between SNPs and mRNA translation, despite the established importance of translational regulation in shaping cell phenotypes. We developed a pipeline analyzing the allelic imbalance in total and polysome-bound mRNAs from paired RNA-seq data of HCT116 cells and identified 40 candidate tranSNPs, i.e. SNPs associated with allele-specific translation. Among them, the SNP rs1053639 (T/A) on DNA damage-inducible transcript 4 (DDIT4) 3UTR was identified, with the reference T allele showing a higher polysome association. rs1053639 TT clones generated by genome editing exhibited significantly higher DDIT4 protein levels than AA ones. The difference in DDIT4 proteins was even greater when cells were treated with Thapsigargin or Nutlin, two perturbations that induce DDIT4 transcription. The RNA-binding protein RBMX influenced these allele-dependent differences in DDIT4 protein expression, as shown by RNA-EMSA, RIP, and smiFISH assays. RBMX depletion reduced DDIT4 protein in TT clones to the AA levels. Functionally, TT clones more effectively repressed mTORC1 under ER stress, while AA clones outcompeted TT clones in vitro or when injected in zebrafish embryos. RBMX depletion increased the fitness of TT cells in co-culture experiments. The rs1053639 AA genotype, under a recessive model, correlates with poor prognosis in TCGA cancer data. Key points- Translatome analysis in HCT116 cells revealed allele-specific mRNA translation for 40 SNPs - rs1053639 (T/A) in DDIT4 3UTR showed allelic differences in mRNA localization & protein expression - AA cells showed weaker mTOR inhibition & higher proliferation; AA individuals had poorer prognosis

molecular biology↗

bioRxiv2024

Caspase-2 kills cells with extra centrosomes

Centrosomes are membrane-less organelles that orchestrate a wide array of biological functions by acting as microtubule organizing centers. Here, we report that caspase-2-driven apoptosis is elicited in blood cells failing cytokinesis and that extra centrosomes are necessary to trigger this cell death. Activation of caspase-2 depends on the PIDDosome multi-protein complex and priming of PIDD1 at extra centrosomes is necessary for this pathway. Accordingly, loss of its centrosomal adapter, ANKRD26, allows for cell survival and unrestricted polyploidization in response to cytokinesis failure. Mechanistically, cell death is initiated upstream of mitochondria via caspase-2-mediated processing of the BCL2 family protein BID, driving BAX/BAK-dependent mitochondrial outer membrane permeabilization (MOMP). Remarkably, BID-deficient cells enforce apoptosis by engaging p53-dependent pro-apoptotic transcriptional responses initiated by caspase-2. Consistently, BID and MDM2 act as shared caspase-2 substrates, with BID being kinetically favored. Our findings document that the centrosome limits its own unscheduled duplication by the induction of PIDDosome-driven mitochondrial apoptosis to avoid potentially pathogenic polyploidization events.

cell biology↗

bioRxiv2023

The mitotic surveillance pathway requires PLK1-dependent 53BP1 displacement from kinetochores

53BP1 acts at the crossroads between DNA repair and p53-mediated stress response. With its interactor USP28, it is part of the mitotic surveillance pathway (MSP), a sensor that monitors the duration of cell division, promoting p53-dependent cell cycle arrest when a critical time threshold is surpassed. 53BP1 dynamically associates with kinetochores, being recruited during prophase, and then undergoing a time-dependent loss of affinity. However, the relevance of this behaviour remains unclear. Here, we identify CENP-F as an interaction partner and kinetochore receptor for 53BP1. By engineering human cells with a CENP-F point mutation, we demonstrate that preventing 53BP1 kinetochore localization does not reduce MSP proficiency. Strikingly, however, preventing the loss of 53BP1 from the kinetochore by inhibiting Polo-like kinase 1 (PLK1) restrains MSP activity, a phenomenon that is abrogated in the CENP-F mutant condition. Taken together, we demonstrate that kinetochore-loaded 53BP1 represents an MSP functionally inhibited state and that PLK1-dependent re-localization of 53BP1 represents an important layer of MSP regulation.

cell biology↗