Biology subjects

Barone, G.

Publications and source records attributed to Barone, G..

15 recordsLinked to original sources

bioRxiv2025

The skin commensal yeast Malassezia promotes tissue homeostasis via the aryl hydrocarbon receptor.

As an abundant fungal colonizer of human skin, Malassezia has long been associated with pathological skin conditions, yet its role in skin homeostasis remain poorly understood. Here, we demonstrate that Malassezia furfur plays an active role in maintaining epidermal integrity by producing tryptophan-derived metabolites that activate the aryl hydrocarbon receptor (AhR), a key regulator of keratinocyte differentiation and inflammation. Using a fungal mutant defective in indole production, we show that M. furfur-derived AhR activation is required to restore barrier function and control inflammation in diseased skin. AhR-deficient mice fail to benefit from M. furfur-mediated barrier protection, underscoring the importance of microbial-derived AhR agonists in skin physiology. These findings establish a previously unrecognized mutualistic role for Malassezia in epidermal homeostasis, challenging its perception as solely a pathogenic fungus and expanding our understanding of the skin microbiotas influence on barrier function and immune regulation. KEY FINDINGSO_LIMalassezia-derived indoles reprogram epidermal gene expression to enhance keratinocyte function. C_LIO_LIAhR activation by Malassezia restores skin barrier integrity and reduces inflammation. C_LIO_LIMalassezia Sul1-dependent tryptophan metabolism is essential for the production of AhR agonists. C_LIO_LIThe barrier protective effects of Malassezia are mediated specifically through keratinocyte intrinsic AhR signaling. C_LI

microbiology↗

bioRxiv2024

AGAPE (computAtional G-quadruplex Affinitiy PrEdiction): The first AI In-silico workflow for G-quadruplex binding affinity prediction.

AGAPE (computational G-quadruplex Affinity Prediction) is a novel machine learning (ML)-based tool designed to predict the binding and stabilizing potential of small molecules targeting G-quadruplexes (G4s). G4s, prevalent in telomeres and oncogene promoters, are promising therapeutic targets, but designing selective binders remains challenging. Building upon a curated dataset of 1217 compounds labelled through Forster Resonance Energy Transfer (FRET) melting assays, AGAPE integrates 5666 molecular descriptors, both classical and quantum chemical. It captures features relevant to G4 recognition, driving researcher to predict the potential G4 stabilization of small molecules, including both organic ligands and metal complexes. Among the trained ML models, XGBoost achieved the best performance with an accuracy of nearly 91%, using 489 selected features. SHAP analysis highlighted descriptors related to molecular topology, polarizability, and electrostatic potential as key contributors to the classification. AGAPE is deployed through a user-friendly web interface supporting batch prediction and secure data handling and provides a robust and interpretable tool to accelerate the discovery of G4-stabilizing compounds, integrating quantum chemical information within an ML-driven cheminformatics framework.

bioinformatics↗

bioRxiv2024

Resolving the Structure of a Guanine Quadruplex in TMPRSS2 Messenger RNA by Circular Dichroism and Molecular Modeling

The presence of a guanine quadruplex in the opening reading frame of the messenger RNA coding for the transmembrane serine protease 2 (TMPRSS2) may pave the way to original anticancer and host-oriented antiviral strategy. Indeed, TMPRSS2 in addition to being overexpressed in different cancer types, is also related to the infection of respiratory viruses, including SARS-CoV-2, by promoting the cellular and viral membrane fusion through its proteolytic activity. The design of selective ligands targeting TMPRSS2 messenger RNA requires a detailed knowledge, at atomic level, of its structure. Therefore, we have used an original experimental-computational protocol to predict the first resolved structure of the parallel guanine quadruplex secondary structure in the RNA of TMPRSS2, which shows a rigid core flanked by a flexible loop. This represents the first atomic scale structure of the guanine quadruplex structure present in TMPRSS2 messenger RNA.

biophysics↗

bioRxiv2023

Mechanism of the Covalent Inhibition of Human Transmembrane Protease Serine 2 as an Original Antiviral Strategy

The Transmembrane Protease Serine 2 (TMPRSS2) is a human enzyme which is involved in the maturation and post-translation of different proteins. In addition of being overexpressed in cancer cells, TMPRSS2 plays a further fundamental role in favoring viral infections by allowing the fusion of the virus envelope and the cellular membrane, notably in SARS-CoV-2. In this contribution we resort to multiscale molecular modeling to unravel the structural and dynamical features of TMPRSS2 and its interaction with a model lipid bilayer. Furthermore, we shed light into the mechanism of action of a potential inhibitor (Nafamostat), determining the free-energy profile associated with the inhibition reaction, and showing the facile poisoning of the enzyme. Our study, while providing the first atomistically resolved mechanism of TMPRSS2 inhibition, is also fundamental in furnishing a solid framework for further rational design targeting transmembrane proteases in a host-directed antiviral strategy. TOC GRAPHICS O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=193 SRC="FIGDIR/small/537985v1_ufig1.gif" ALT="Figure 1"> View larger version (108K): org.highwire.dtl.DTLVardef@19dd8c9org.highwire.dtl.DTLVardef@394c0org.highwire.dtl.DTLVardef@11ad383org.highwire.dtl.DTLVardef@347a8c_HPS_FORMAT_FIGEXP M_FIG C_FIG

biophysics↗

bioRxiv2023

Resolving a Guanine-Quadruplex Structure in the SARS-CoV-2 Genome through Circular Dichroism and Multiscale Molecular Modeling.

The genome of SARS-CoV-2 coronavirus is made up of a single-stranded RNA fragment that can assume a specific secondary structure, whose stability can influence the virus ability to reproduce. Recent studies have identified putative guanine quadruplex sequences in SARS-CoV-2 genome fragments that are involved in coding for both structural and non-structural proteins. In this contribution, we focus on a specific G-rich sequence referred as RG-2, which codes for the non-structural protein 10 (Nsp10) and assumes a guanine-quadruplex (G4) arrangement. We provide the secondary structure of the RG-2 G4 at atomistic resolution by molecular modeling and simulation, validated by the superposition of experimental and calculated electronic circular dichroism spectrum. Through both experimental and simulation approaches, we have demonstrated that pyridostatin (PDS), a widely recognized G4 binder, can bind to and stabilize RG-2 G4 more strongly than RG-1, another G4 forming sequence that was previously proposed as a potential target for antiviral drug candidates. Overall, this study highlights RG-2 as a valuable target to inhibit the translation and replication of SARS-CoV-2 paving the way towards original therapeutic approaches against emerging RNA viruses.

biophysics↗

bioRxiv2023

Predicting the Three-dimensional Structure of the c-KIT Oncogene Promoter and the Dynamics of Strongly Coupled Guanine-Quadruplexes

Guanine-quadruplexes (G4s) are non-canonical DNA structures that play important protective and regulatory roles within cells, influencing, for instance, gene expression. Although the secondary structure of many human G4s is well characterized, in several gene-promoter regions multiple G4s are located in close proximity and may form three-dimensional structures which could ultimately influence their biological roles. In this contribution, we analyze the interplay between the three neighboring G4s present in the c-KIT proto-oncogene promoter, namely WK1, WSP and WK2. In particular, we highlight how these three G4s are structurally linked and how their crosstalk favors the formation of a parallel structure for WSP, differently from what observed for this isolated G4 in solution. Relying on all-atom molecular dynamic simulations exceeding the s time-scale and using enhanced sampling methods, we provide the first computationally-resolved structure of a well-organized G4 cluster in the promoter of a crucial gene involved in cancer development. Our results indicate that neighboring G4s influence their mutual three-dimensional arrangement and provide a powerful tool to predict and interpret complex DNA structures that ultimately can be used as starting point for drug discovery purposes.

biophysics↗

bioRxiv2022

G-quadruplex recognition by DARPIns through epitope/paratope analogy

We investigated the mechanisms leading to the specific recognition of Guanine Guadruplex (G4) by DARPins peptides, which can lead to the design of G4s specific sensors. To this end we carried out all-atom molecular dynamic simulations to unravel the interactions between specific nucleic acids, including human-telomeric (h-telo), Bcl-2, and c-Myc, with different peptides, forming a DARPin/G4 complex. By comparing the sequences of DARPin with that of a peptide known for its high affinity for c-Myc, we show that the recognition cannot be ascribed to sequence similarity but, instead, depends on the complementarity between the three-dimensional arrangement of the molecular fragments involved: the -helix/loops domain of DARPin and the G4 backbone. Our results reveal that DARPins tertiary structure presents a charged hollow region in which G4 can be hosted, thus the more complementary the structural shapes, the more stable the interaction.

biophysics↗

bioRxiv2021

Structure of the 5' untranslated region in SARS-CoV-2 genome and its specific recognition by innate immune system via the human oligoadenylate synthase 1

2-5-Oligoadenylate synthetase 1 (OAS1) is one of the key enzymes driving the innate immune system response to SARS-CoV-2 infection whose activity has been related to COVID-19 severity. In particular, OAS1 is a sensor of endogenous RNA that triggers the 2-5 oligoadenylate/RNase L pathway in response to viral infections, ultimately activating the RNA-Lyase which cleaves endogenous and exogenous RNA impeding the viral maturation. Upon SARS-CoV-2 infection, OAS1 is responsible for the recognition of viral RNA and has been shown to possess a particularly high sensitivity for the 5-untranslated (5-UTR) RNA region, which is organized in a double-strand stem loop motif (SLA). Since the structure of the nucleic acid/protein complex has not been resolved, here we report its structure obtained by molecular modeling, including enhanced sampling approaches. We also pinpoint that the SL1 region enhances the interaction network with the enzyme, promoting specific hydrogen bonds, absent in normal double strand RNA fragments, hence rationalizing the high affinity for OAS1.

biophysics↗

bioRxiv2021

Never cared for what they do. High structural stability of Guanine-quadruplexes in presence of strand-break damages

DNA integrity is an important factor to assure genome stability and, more generally, cells and organisms viability. In presence of DNA damage, the normal cell cycle is perturbed while cells activate their repair processes. Although efficient, the repair system is not always able to ensure the complete restoration of gene integrity. In these cases, not only mutations may occur, but the accumulation of lesions can either lead to carcinogenesis or reach a threshold which induces apoptosis and the programmed cell death. Among the different types of DNA lesions, strand breaks produced by ionizing radiations are the most toxic, due to their inherently difficult repair, which may lead to genomic instability. In this article we show, by using classical molecular simulations techniques, that differently from the canonical double-helical B-DNA, guanine-quadruplex (G4) arrangements show a remarkable structural stability, even in presence of two strand breaks. Since G4-DNA are recognized for their regulatory roles in cell senescence and gene expression, also involving oncogene, their stability can be related to an evolutionary cellular response aimed at minimizing the effects of ionizing radiation.

biophysics↗

bioRxiv2021

How fragile we are. Influence of STimulator of INterferon Genes, STING, variants on pathogen recognition and immune response efficiency

The STimulator of INterferon Genes (STING) protein is a cornerstone of the human immune response. Its activation by cGAMP upon the presence of cytosolic DNA stimulates the production of type I interferons and inflammatory cytokines which are crucial for protecting cells from infections. STING signaling pathway can also influence both tumor-suppressive and tumor-promoting mechanisms, rendering it an appealing target for drug design. In the human population, several STING variants exist and exhibit dramatic differences in their activity, impacting the efficiency of the host defense against infections. Understanding the differential molecular mechanisms exhibited by these variants is of utmost importance notably towards personalized medicine treatments against diseases such as viral infections (COVID-19, Dengue...), cancers, or auto-inflammatory diseases. Owing to micro-seconds scale molecular modeling simulations and post-processing by contacts analysis and Machine Learning techniques, we reveal the dynamical behavior of four STING variants (wild type, G230A, R293Q, and G230A-R293Q) and we rationalize the variability of efficiency observed experimentally. Our results show that the decrease of STING activity is linked to a stiffening of key-structural features of the binding cavity, together with changes of the interaction patterns within the protein.

biochemistry↗

bioRxiv2021

Structure and dynamics of RNA guanine quadruplexes in SARS-CoV-2 genome. Original strategies against emerging viruses

Guanine quadruplexes (G4) structures in viral genome have a key role in modulating viruses biological activity. While several DNA G4 structures have been experimentally resolved, RNA G4s are definitely less explored. We report the first calculated G4 structure of the RG-1 RNA sequence of SARS-CoV-2 genome, obtained by using a multiscale approach combining quantum and classical molecular modelling and corroborated by the excellent agreement between the corresponding calculated and experimental circular dichroism spectra. We prove the stability of RG-1 G4 arrangement as well as its interaction with G4 ligands potentially inhibiting viral protein translation.

biophysics↗

bioRxiv2020

Forever Young: Structural Stability of Telomeric Guanine-Quadruplexes in Presence of Oxidative DNA Lesions.

Human telomeric DNA (h-Telo), in G-quadruplex (G4) conformation, is characterized by a remarkable structural stability that confers it the capacity to resist to oxidative stress producing one or even clustered 8-oxoguanine lesions. We present a combined experimental/computational investigation, by using circular dichroism in aqueous solutions, cellular immunofluorescence assays and molecular dynamics (MD) simulations, that identifies the crucial role of the stability of G4s to oxidative lesions, related also to their biological role as inhibitors of telomerase, an enzyme overexpressed in most cancers associated to oxidative stress.

biophysics↗

bioRxiv2020

Tumor to normal single cell mRNA comparisons reveal a pan-neuroblastoma cancer cell

Neuroblastoma is an embryonal childhood cancer that arises from aberrant development of the neural crest, mostly within the fetal adrenal medulla. It is not established what developmental processes neuroblastoma cancer cells represent. Here, we sought to reveal the phenotype of neuroblastoma cancer cells by comparing cancer (n=16,591) with fetal adrenal single cell transcriptomes (n=57,972). Our principal finding was that the neuroblastoma cancer cell resembled fetal sympathoblasts, but no other fetal adrenal cell type. The sympathoblastic state was a universal feature of neuroblastoma cells, transcending cell cluster diversity, individual patients and clinical phenotypes. We substantiated our findings in 652 neuroblastoma bulk transcriptomes and by integrating canonical features of the neuroblastoma genome with transcriptional signals. Overall, our observations indicate that there exists a pan-neuroblastoma cancer cell state which may be an attractive target for novel therapeutic avenues.

cancer biology↗

bioRxiv2020

Role of RNA Guanine Quadruplexes in Favoring the Dimerization of SARS Unique Domain in Coronaviruses

Coronaviruses may produce severe acute respiratory syndrome (SARS). As a matter of fact, a new SARS-type virus, SARS-CoV-2, is responsible of a global pandemic in 2020 with unprecedented sanitary and economic consequences for most countries. In the present contribution we study, by all-atom equilibrium and enhanced sampling molecular dynamics simulations, the interaction between the SARS Unique Domain and RNA guanine quadruplexes, a process involved in eluding the defensive response of the host thus favoring viral infection of human cells. Our results evidence two stable binding modes involving an interaction site spanning either the protein dimer interface or only one monomer. The free energy profile unequivocally points to the dimer mode as the thermodynamically favored one. The effect of these binding modes in stabilizing the protein dimer was also assessed, being related to its biological role in assisting SARS viruses to bypass the host protective response. This work also constitutes a first step of the possible rational design of efficient therapeutic agents aiming at perturbing the interaction between SARS Unique Domain and guanine quadruplexes, hence enhancing the host defenses against the virus. TOC GRAPHICS O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/029447v2_ufig1.gif" ALT="Figure 1"> View larger version (99K): org.highwire.dtl.DTLVardef@1497e69org.highwire.dtl.DTLVardef@a4c44org.highwire.dtl.DTLVardef@1511b7org.highwire.dtl.DTLVardef@13e12c1_HPS_FORMAT_FIGEXP M_FIG C_FIG

biophysics↗

bioRxiv2019

EML4-ALK V3 drives cell migration through NEK9 and NEK7 kinases in non-small-cell lung cancer

EML4-ALK is an oncogenic fusion present in [~]5% lung adenocarcinomas. However, distinct EML4-ALK variants differ in the length of the EML4 microtubule-associated protein encoded within the fusion and are associated with a poorly understood variability in disease progression and therapeutic response. Here, we show that EML4-ALK variant 3, which is linked to accelerated metastatic spread and worse patient outcome, causes microtubule stabilization, formation of extended cytoplasmic protrusions, loss of cell polarity and increased cell migration. Strikingly, this is dependent upon the NEK9 kinase that interacts with the N-terminal region of EML4. Overexpression of wild-type EML4, as well as constitutive activation of NEK9, also perturbs cell morphology and accelerates cell migration in a manner that requires the downstream kinase NEK7 but not ALK activity. Moreover, elevated NEK9 is associated in patients with EML4-ALK V3 expression, as well as reduced progression-free and overall survival. Hence, we propose that EML4-ALK V3 promotes microtubule stabilization through recruitment of NEK9 and NEK7 to increase cell migration and that this represents a novel actionable pathway that drives disease progression in lung cancer.

cancer biology↗