Biology subjects

Rossi, E.

Publications and source records attributed to Rossi, E..

8 recordsLinked to original sources

bioRxiv2026

TERT interacts with TFAM to activate mitochondrial fragmentation and auto/mitophagy

Previous studies have demonstrated that Telomerase Reverse Transcriptase (TERT) is localized inside mitochondria, where it associates with mitochondrial DNA (mtDNA), thereby influencing replication and transcription. Using a combination of quantitative fluorescence microscopy and biochemistry, we demonstrate that TERT binds indirectly to mtDNA through the interaction with mitochondrial transcription factor A (TFAM) to induce mitochondrial fragmentation. These findings reveal a novel mitochondrial interaction involving TERT and highlight a role for TERT and TFAM in the regulation of auto/mitophagy. This interaction is an important factor for mitochondrial function and contributes to the remodelling of mitochondrial respiratory capacity.

cell biology↗

bioRxiv2026

Resistance to antibacterial peptide nucleic acids through altered ribosome function

When used as antibacterial agents, Peptide Nucleic Acid (PNAs) are generally designed to base-pair with complementary sequences of an essential mRNA and block translation initiation. Although bacterial susceptibility to peptide-conjugated PNAs is strongly influenced by cellular uptake, intracellular determinants of PNA activity remain poorly understood. Here, we identify a ribosome-centered mechanism of resistance to antibacterial PNAs in Escherichia coli. The rpsLI82N mutation increased the minimum inhibitory concentration (MIC) of an argininerich cell penetrating peptide-conjugated PNA targeting acpP eightfold. The effect of rpsLI82N was additive with mutations that reduce PNA entry into bacterial cells PNA resistance conferred by rpsLI82N was independent of carrier peptide and also applied when naked PNA was tested in an envelope-permeable strain. Similarly, rpsLI82N-associated resistance was independent of the targeted mRNA, as it applied to PNAs targeting either the Shine-Dalgarno or AUG region of acpP or ftsZ mRNA. Several additional substitutions within residues 74-82 of ribosomal protein uS12 conferred PNA resistance. Because resistance occurred among both error-restrictive and ribosomal-ambiguity alleles, it did not correlate with the classical decoding-fidelity phenotypes measured by stop-codon readthrough. Proteomic analysis revealed widespread changes in proteins under post-transcriptional control in rpsLI82N cells. The effect on selected sRNA-regulated genes correlated with the location of the sRNA-binding site: repression was less efficient when binding overlapped the translation-initiation region whereas it was more efficient when regulatory sites were located outside this region. In parallel, rpsLI82N increased the 30S and 50S ribosomal fractions and reduced the 70S fraction. Both loss of KsgA, which disrupts 30S maturation, and treatment with kasugamycin, which perturbs translation initiation, increased PNA resistance. We propose that rpsLI82N alters uS12-dependent 30S assembly and initiation-complex dynamics, thereby changing the effective occupancy of mRNA translation-initiation regions. This limits access of PNAs and sRNAs to overlapping sequences, resulting in PNA resistance and reduced sRNA-mediated repression. Conversely, a longer-lived 30S initiation state may facilitate sRNA binding to flanking regions and strengthen repression. These findings identify the ribosome-mRNA interface as an intracellular determinant of antibacterial PNA susceptibility.

molecular biology↗

bioRxiv2024

Tumor-associated macrophages enhance tumor innervation and spinal cord repair

AO_SCPLOWBSTRACTC_SCPLOWTumor-associated macrophages (TAM) enhance cancer progression by promoting angiogenesis, extracellular matrix (ECM) remodeling, and immune suppression. Nerve infiltration is a hallmark of various cancers and is known to directly contribute to tumor growth. However, the role of TAM in promoting intratumoral nerve growth remains poorly understood. In this study, we demonstrate that TAM expressed a distinct "neural growth" gene signature. TAM actively enhance neural growth within tumors and directly promote neurites outgrowth. We identify secreted phosphoprotein 1 (Spp1) as a key mediator of TAM-driven neural growth activity, which triggers neuronal mTORC2 signaling. Leveraging this new neural growth function, which added to the TAM wound healing properties, we explored TAM potential to repair central nervous system. Adoptive transfer of in vitro-generated TAM in a severe complete-compressive-contusive spinal cord injury (scSCI) model, not only repaired the damaged neural parenchyma by improving tissue oxygenation, ECM remodeling, and dampening chronic inflammation, but also resulted in neural regrowth and partial functional motor recovery. Proteomic analysis and subsequent functional validation confirmed that TAM-induced spinal cord regeneration is mediated through the activation of neural mTORC2 signaling pathways. Collectively, our data unveil a previously unrecognized role of TAM in tumor innervation, neural growth, and neural tissue repair.

neuroscience↗

bioRxiv2024

The antimycotic 5-fluorocytosine is a virulence inhibitor of uropathogenic Escherichia coli and eradicates biofilm-embedded bacteria synergizing with β-lactams

ObjectivesBiofilm increases bacterial antibiotic tolerance, posing a challenge for treating biofilm-associated infections in clinical settings. 5-fluorocytosine (5-FC), an FDA-approved antifungal and antitumor drug, has been shown to inhibit virulence factor production and biofilm formation in Gram-negative bacteria. This work aims to determine whether 5-FC antivirulence and antibiofilm activity are preserved in clinical E. coli isolates and to test possible synergies with antibiotics in treating preformed biofilm. Methods5-FC ability to inhibit biofilm formation, disrupt mature biofilm, and modulate virulence determinants was tested on uropathogenic E. coli (UPEC) clinical strains using the Crystal Violet-based biofilm adhesion and minimum biofilm eradication concentration assays. Gene expression was measured by RT-qPCR. The effect on bacterial viability within preformed biofilm was monitored using fluorescein diacetate and by determining colony-forming units in biofilm treated with or without 5-FC and specific antibiotics. Bladder epithelial cell cultures were used to assess the effect of 5-FC on UPEC adherence and cytotoxicity. Results5-FC inhibited biofilm formation in all tested UPEC strains. Gene expression analysis suggested that 5-FC concurrently inhibits the expression of genes encoding curli fibers, a major adhesion factor in E. coli, as well as other virulence determinants such as secreted toxins and type I and P fimbriae. Accordingly, 5-FC reduced UPEC adherence to epithelial cells and promoted host cell survival. Although 5-FC could not disrupt preformed biofilm, combining 5-FC with {beta}-lactams drastically reduced the viability of biofilm-resident bacteria. Conclusions5-FC shows antibiofilm and antivirulence activity against uropathogenic E. coli strains by reducing the expression of several virulence factors and the overall UPEC pathogenic potential. In combination with {beta}-lactams, 5-FC eradicates bacteria within mature biofilms, which are known to be highly refractory to antibiotic treatment. Our data suggest that 5-FC is an excellent candidate for preventing and treating bacterial infections associated with recalcitrant biofilms.

microbiology↗

bioRxiv2024

Releasing the octoPus, an open-source digital tool to promote Integrated Pest Management

Meeting the EU targets to halve chemical pesticide use by 2030 necessitates European farmers to adopt Integrated Pest Management principles as the standard. Decision support systems are valuable tools to meet this target and rely on individual disease models to identify conducive conditions to fungal infections. These models are often proprietary assets of digital startups and agrochemical companies, leading to a lack of transparency for farmers and a bias towards chemical solutions over sustainable practices. We present octoPus, the first free digital tool designed to support the control of primary infections of grapevine downy mildew, and we evaluate its performance and behavior on a wide set of environmental conditions and agricultural contexts. We implemented eight models from scientific articles (Rule310, Laore, EPI, IPI, DMcast, UCSC, Misfits, Magarey, the "tentacles"), and evaluated them across Italian grapevine areas from 2001 to 2020. Model outputs were integrated with phenology and susceptibility models (the "eyes"), which were calibrated using data from regional extension services bulletins. The simulated infections serve as predictors in a Random Forest algorithm ("brain") that elaborates an overall risk level (very low to very high). The Llama large language model is used to generate user-supportive messages (the "mouth"). octoPus is released as an open-source software, which reads weather data, executes the models, and presents outputs in natural language and symbolic syntax. Our results showed reasonable accuracy in simulating grapevine phenology (RMSE = 9-10 days) and seasonal risk (RMSE {approx} 0.75). The infection models consistently identified a moisture and thermal north-south suitability gradient in Italy and accurately detected years with low or high downy mildew pressure. However, the models displayed significant differences in the number and dynamics of simulated infections, with two distinct patterns within the ensemble. By developing and releasing the first free and open-source tool to support the control of grapevine downy mildew, we address a critical gap in the availability and transparency of decision support systems for European farmers. Unlike proprietary models that often lack transparency and may favor agribusiness logic, octoPus provides a comprehensive and accessible alternative that promotes Integrated Pest Management practices. We propose the adoption of octoPus by plant health authorities to identify areas for performance refinement and capabilities expansion.

ecology↗

bioRxiv2024

PLINDER: The protein-ligand interactions dataset and evaluation resource

Protein-ligand interactions (PLI) are foundational to small molecule drug design. With computational methods striving towards experimental accuracy, there is a critical demand for a well-curated and diverse PLI dataset. Existing datasets are often limited in size and diversity, and commonly used evaluation sets suffer from training information leakage, hindering the realistic assessment of method generalization capabilities. To address these shortcomings, we present PLIN-DER, the largest and most annotated dataset to date, comprising 449,383 PLI systems, each with over 500 annotations, similarity metrics at protein, pocket, interaction and ligand levels, and paired unbound (apo) and predicted structures. We propose an approach to generate training and evaluation splits that minimizes task-specific leakage and maximizes test set quality, and compare the resulting performance of DiffDock when retrained with different kinds of splits.

biochemistry↗

bioRxiv2024

Molecular modeling of Proteinase-Activated Receptor 1 in complex with Thrombin Receptor Activator Peptide 6.

The protease-activated receptor 1 (PAR1) and its activator thrombin re-ceptor activator peptide 6 (TRAP6) play crucial roles in various physiologi-cal and pathological processes, including hemostasis, thrombosis, and cancer progression. Although the interaction between PAR1 and TRAP6 has been heavily studied using experimental technique such as mutagenesis, structural data remains scarce due to the technical hardship of studying membrane pro-teins such as PAR1. In this study, we employed an integrative modeling approach to elucidate the structure of the PAR1-TRAP6 complex. Leveraging state-of-the-art AI-based protein modeling tools, including AlphaFold2 and ESMFOLD, we in-tegrated HADDOCK, a physics-based method to refine predictions. Overall, the predicted structures are in good agreement with the experimental data available in the literature. Our model unveiled a new T-shaped pi-stacking interaction between TRAP6s F2 and PAR1s Y360. The integrative modeling approach combining the predictions of the deep learning model with a physics-based method proves to be an interesting strat-egy for solving challenging membrane protein structures with high confidence. Our model of the PAR1-TRAP6 complex will be an interesting starting point for further investigation of the activation of PAR1 by TRAP6.

bioinformatics↗

bioRxiv2023

Cystic fibrosis systemic immune profile is associated with lung microbes and characterized by widespread alterations in the innate and adaptive immune compartments

Polymicrobial airway infections and detrimental inflammation characterize patients with cystic fibrosis (CF), a disease with heterogeneous clinical outcomes. How the overall immune response is affected in CF, its relationships with the lung microbiome, and the source of clinical heterogeneity are unclear. Our work identifies a specific CF immune profile characterized by widespread hyperactivation, enrichment of CD35+/CD49d+ neutrophils, and reduction in dendritic cells. Further, our data indicate signs of immune dysregulation due to alterations in Tregs homeostasis, which, together with an impaired B-cell immune function, are linked with patients lung function and are potentially the source of clinical heterogeneity. Indeed, clinical heterogeneity does not stem from a specific lung microbiome; yet, commensal bacteria correlate with higher concentrations of circulating immune cells and lower expression of leukocyte activation markers, a condition reversed by pathogenic microorganisms. Overall, our findings provide unique markers and immunomodulatory targets for improving the treatment of CF.

immunology↗