Biology subjects

Barazzuol, L.

Publications and source records attributed to Barazzuol, L..

6 recordsLinked to original sources

bioRxiv2026

A two-step organoid screen identifies transient p53 activation as a senolytic strategy for radiation-induced salivary gland dysfunction

Radiotherapy significantly improves the survival of head and neck cancer patients. However, it frequently damages the salivary glands, causing persistent hyposalivation and xerostomia. Radiation-induced cellular senescence within the salivary gland stem/progenitor cell niche contributes to hyposalivation, suggesting that selective elimination of senescent cells could promote tissue recovery. However, the effectiveness of senolytic compounds is strongly context dependent, varying with tissue of origin and potentially impairing regenerative cells required for functional restoration. Here, we developed a two-step organoid-based screening methodology that integrates the preferential induction of apoptosis in irradiated, senescence enriched, salivary gland organoids with the preservation of stem/progenitor cell regenerative capacity. As a first step, the senolytic activity of candidate drugs was tested to identify drugs that induced apoptosis in senescent cells of irradiated organoids but were not or less toxic to unirradiated organoids. As a second step, the confirmed senolytic compounds were tested for effects on stem cell self-renewal potential. Using this approach, we identified Nutlin3a, an MDM2 inhibitor and p53 activator, as the compound with the most favorable toxicity profile in salivary glands. Last, we confirmed the anti-senescence and pro-regenerative potential of Nutlin3a in an in vivo mouse model of radiation-induced hyposalivation, where localized Nutlin3a delivery resulted in a robust increase in saliva production, as early as two weeks after administration. These findings establish an organoid-based strategy for identifying tissue-adapted senolytic interventions and propose transient local p53 activation with Nutlin3a as a potential approach to mitigate radiation-induced salivary gland dysfunction.

cell biology↗

bioRxiv2024

Notch Signaling Drives Pro-Regenerative and Migratory Traits in Glandular Stem/Progenitor Cells

Organoid models have advanced our understanding of adult stem/progenitor cell dynamics and function. However, uncovering the regulatory mechanisms of scarce and often quiescent stem cells in organs like the salivary glands remains challenging. Using single-cell RNA sequencing and bulk ATAC and RNA-sequencing analysis, we conducted in-depth profiling of the cellular populations and key signaling pathways characterizing a mouse submandibular salivary gland organoid (mSGO) model at different temporal stages and in response to radiation damage. We identified Sox9- and Itgb1-expressing cells as the most primitive adult stem/progenitor populations and uncover novel stemness and migratory roles for Cd44-expressing cells. Moreover, we revealed that Notch signaling is essential for maintaining self-renewal and migration potential of these stem/progenitor cells post-irradiation. Extending these findings to patient-derived mSGOs, as well as murine and patient-derived mammary and thyroid gland organoids, we confirmed Notch signaling as a conserved regulator of stem/progenitor cell function under migrative and regenerative conditions.

cell biology↗

bioRxiv2024

Derepression of transposable elements enhances interferon beta signaling and stem/progenitor cell activity after proton irradiation.

Radiotherapy is a mainstay in cancer treatment, aiming to maximize DNA damage in tumors while minimizing harm to surrounding healthy tissues. However, the collateral damage to normal tissues, especially stem/progenitor cells essential for tissue regeneration and organ function, remains a significant challenge. Here, we investigate the molecular responses to photon and proton irradiation, two key modalities in head and neck cancer treatment, using organoids. Multiomics analysis reveals a stronger double-stranded RNA (dsRNA)-induced type I interferon (IFN-I) response following proton irradiation, driven by loss of heterochromatin regulators and derepression of transposable elements (TEs). This response, mediated by the cytoplasmic sensor RIG-I, enhances the inflammatory signaling initiated by the canonical dsDNA sensors cGAS and ZBP1. Genetic and pharmacological modulation of IFN-I signaling in vitro and in vivo demonstrates its critical role in enhancing stem/progenitor cell activity post-irradiation. Our findings reveal a pro-regenerative role of TE derepression-mediated IFN-I response suggesting this pathway as a promising therapeutic target to mitigate radiation-induced side effects. TeaserTransposable element-mediated type I interferon signaling enhances stem/progenitor cell activity after irradiation.

cell biology↗

bioRxiv2023

Radiotherapy induces persistent innate immune reprogramming of microglia into a primed state

More than half of all brain tumour survivors experience debilitating and often progressive cognitive decline after treatment with radiotherapy. Microglia, the resident macrophages in the brain, have been implicated in this decline. In response to various insults microglia can develop innate immune memory (IIM), which can either enhance (priming) or repress (tolerance) the response to subsequent inflammatory challenges. Here, we investigated whether radiation affects the IIM of microglia by irradiating the brains of rats and later exposing them to a secondary inflammatory stimulus. Comparative transcriptomic profiling and protein validation of microglia isolated from irradiated rats showed a stronger immune response to a secondary inflammatory insult demonstrating that radiation can lead to long-lasting molecular reprogramming of microglia. Transcriptomic analysis of post-mortem normal-appearing non-tumour brain tissue of glioblastoma patients indicates that radiation-induced microglial priming is conserved in humans. Targeting microglial priming after radiotherapy or avoiding further inflammatory insults could decrease radiotherapy-induced neurotoxicity.

neuroscience↗

bioRxiv2022

Glioblastoma is associated with extensive accelerated brain ageing

Progressive neurocognitive dysfunction is the leading cause of a reduced quality of life in patients with primary brain tumours. Understanding the mechanisms underlying cognitive impairments that occur in response to a brain tumour and its treatment is essential to improve patients quality of life. Here, we show that normal-appearing non-tumour brain regions of patients with glioblastoma display hallmarks of accelerated ageing and share multiple features with Alzheimers disease patients. Integrated transcriptomic and tissue analysis shows that normal-appearing brain tissue from glioblastoma patients has a significant overlap with brain tissue from Alzheimers disease patients, revealing shared mitochondrial and neuronal dysfunction, and proteostasis deregulation. Overall, the brain of glioblastoma patients undergoes Alzheimers disease-like accelerated ageing, providing novel or repurposed therapeutic targets for managing brain cancer-related side effects.

neuroscience↗

bioRxiv2021

Targeting DNA topoisomerases or checkpoint kinases results in an overload of chaperone systems, triggering aggregation of a metastable subproteome

A loss of the checkpoint kinase ATM leads to impairments in the DNA damage response, and in humans causes cerebellar neurodegeneration, and a high risk to cancer. A loss of ATM is also associated with increased protein aggregation. The relevance and characteristics of this aggregation are still incompletely understood. Moreover, it is unclear to what extent other genotoxic conditions can trigger protein aggregation as well. Here, we show that targeting ATM, but also ATR or DNA topoisomerases result in a similar, widespread aggregation of a metastable, disease-associated subfraction of the proteome. Aggregation-prone model substrates, including Huntingtin exon1 containing an expanded polyglutamine repeat, aggregate faster under these conditions. This increased aggregation results from an overload of chaperone systems, which lowers the cell-intrinsic threshold for proteins to aggregate. In line with this, we find that inhibition of the HSP70 chaperone system further exacerbates the increased protein aggregation. Moreover, we identify the molecular chaperone HSPB5 as a potent suppressor of it. Our findings reveal that various genotoxic conditions trigger widespread protein aggregation in a manner that is highly reminiscent of the aggregation occurring in situations of proteotoxic stress and in proteinopathies.

molecular biology↗