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Biology subjects

Gentile, S.

Publications and source records attributed to Gentile, S..

5 recordsLinked to original sources

An agent-based 3D model of non-genetic adaptation in cancer tissues under electrical, mechanical, and hypoxic stress

Non-genetic adaptation enables cancer cells to alter their phenotype under stress without requiring new mutations. However, the mechanisms by which electrical, mechanical, and hypoxic cues combine to shape this process in 3D tissues remain poorly understood. This work presents an agent-based tumor model that integrates vascular oxygen supply, a globally imposed electric field, mechanically mediated crowding and compression cues, phenotype transitions, cell growth, mitosis, death, and inheritance of adaptive memory across division. The simulated tumors exhibit a three-stage trajectory consisting of necrosis onset, transient collapse of live mass, and partial regrowth accompanied by progressive accumulation of adapted cells. Continuous electrical stimulation produces a dose-dependent reduction in live mass while markedly increasing the adapted fraction, with comparatively limited changes in final necrotic burden. This response is strongly conditioned by mechanics and reshapes (and is reshaped by) adaptive capacity. Pulsed stimulation further shows that, in the model, electric field amplitude and temporal schedule jointly determine memory phenomena, phenotypic diversification, and growth recovery. These results show that coupling local oxygen availability, mechanical constraints, electrical forcing, and history-dependent phenotype transitions can generate distinct tissue-level patterns of phenotypic heterogeneity. Both stimulus magnitude and temporal protocol influenced the resulting population structure, suggesting that the history of physical stress may be an important determinant of adaptive dynamics in spatially organized tumor models.

biophysics↗

Metallothionein loss in cancer cells contributes to increased mutations through defective DNA repair and metabolic imbalance

Understanding which genes are involved in mutagenesis is essential for developing cancer prevention and treatment strategies; establishing protectors of the genome has revolutionized cancer biology. Here, we describe metallothionein (MT) proteins as previously uncharacterized protectors against mutagenesis. MT is a heavy metal binding protein essential for zinc homeostasis and protection against heavy metal cytotoxicity. Because zinc binds approximately 10-15% of the proteome and is critical for processes such as DNA repair and mitochondrial health, MT loss is expected to disrupt these processes. We hypothesized that MT loss induces genomic instability by impairing DNA repair and mitochondrial function. In this study, the consequences of MT deficiency in high-grade serous ovarian cancer (HGSC) were investigated by knockdown of the most highly expressed MT, MT2A. Loss of MT2A resulted in the impaired DNA repair pathway base excision repair (BER), leading to increased mutagenesis. MT2A deficiency produced mitochondrial dysfunction, characterized by a decrease in mitochondrial membrane potential, glycolysis, oxidative phosphorylation, amino acids, and an imbalance of nucleobases. Together, these defects reflect cellular states associated with increased cancer aggressiveness. These findings identify MT as a fundamental hub maintaining genomic and metabolic integrity. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=84 SRC="FIGDIR/small/736843v2_ufig1.gif" ALT="Figure 1"> View larger version (23K): org.highwire.dtl.DTLVardef@1af4adeorg.highwire.dtl.DTLVardef@15c588forg.highwire.dtl.DTLVardef@1ba5181org.highwire.dtl.DTLVardef@13d150b_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

Enzyme-Responsive DNA Condensates

Membrane-less compartments and organelles are widely acknowledged for their role in regulating cellular processes, and there is an urgent need to harness their full potential as both structural and functional elements of synthetic cells. Despite rapid progress, synthetically recapitulating the nonequilibrium, spatially distributed responses of natural membrane-less organelles remain elusive. Here we demonstrate that the activity of nucleic-acid cleaving enzymes can be localised within DNA-based membrane-less compartments by sequestering the respective DNA or RNA substrates. Reaction-diffusion processes lead to complex nonequilibrium patterns, dependent on enzyme concentration. By arresting similar dynamic patterns, we spatially organise different substrates in concentric sub-compartments, which can be then selectively addressed by different enzymes, demonstrating spatial distribution of enzymatic activity. Besides advancing our ability to engineer advanced biomimetic functions in synthetic membrane-less organelles, our results may facilitate the deployment of DNA-based condensates as microbioreactors or platforms for the detection and quantitation of enzymes and nucleic acids.

synthetic biology↗

Conserved long noncoding RNA TILAM promotes liver fibrosis through interaction with PML in hepatic stellate cells

Background & AimsFibrosis is the common endpoint for all forms of chronic liver injury, and progression of fibrosis leads to the development of end-stage liver disease. Activation of hepatic stellate cells (HSCs) and their transdifferentiation to myofibroblasts results in the accumulation of extracellular matrix (ECM) proteins that form the fibrotic scar. Long noncoding (lnc) RNAs regulate the activity of HSCs and may provide targets for fibrotic therapies. MethodsWe identified lncRNA TILAM as expressed near COL1A1 in human HSCs and performed loss-of-function studies in human HSCs and liver organoids. Transcriptomic analyses of HSCs isolated from mice defined the murine ortholog of TILAM. We then generated Tilam-deficient GFP reporter mice and quantified fibrotic responses to carbon tetrachloride (CCl4) and choline-deficient L-amino acid defined high fat diet (CDA-HFD). Co-precipitation studies, mass spectrometry, and gene expression analyses identified protein partners of TILAM. ResultsTILAM is conserved between human and mouse HSCs and regulates expression of ECM proteins, including collagen. Tilam is selectively induced in HSCs during the development of fibrosis in vivo. In both male and female mice, loss of Tilam results in reduced fibrosis in the setting of CCl4 and CDA-HFD injury models. TILAM interacts with promyelocytic leukemia protein (PML) to stabilize PML protein levels and promote the fibrotic activity of HSCs. ConclusionTILAM is activated in HSCs and interacts with PML to drive the development of liver fibrosis. Depletion of TILAM may serve as a therapeutic approach to combat the development of end stage liver disease.

cell biology↗

Deficits of Hippocampal RNA Editing and Social Interaction Resulting from Prenatal Stress are Mitigated by Clozapine.

BackgroundNeurodevelopmental deficits resulting from prenatal stress are associated with neurological disorders that include deficits of social behavior, such as schizophrenia1 and autism2-7. Studies of human brain and animal models indicate that an epitranscriptomic process known as RNA editing contributes to the pathophysiology of these disorders, which occur more frequently in males than in females8-20. RNA editing plays an important role in brain development through its modification of excitatory and inhibitory neurotransmission21. MethodsWe exposed pregnant mice to restraint stress three times daily during gestational weeks 2 and 3. We treated the adult male offspring with haloperidol (1mg/kg), clozapine (5mg/kg) or saline twice daily for 5 days. Subsequently we measured social interaction behavior (SI) and locomotor activity, followed by next-generation sequencing analyses of hippocampal RNA editing. ResultsMice exposed to PRS exhibited reduced SI, which correlated with hippocampal RNA editing of -amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunits GluA2, GluA3 and GluA4, the potassium channel Kv1.1, the calcium channel subunit Cav1.3, calcium-dependent secretion activator (CAPS-1) and the calcium-dependent cell adhesion protein, cadherin 22 (CDH22). Treatment with clozapine, but not haloperidol, normalized SI behavior, and selectively reduced the deficits in GluA2 RNA editing in PRS mice. ConclusionsRNA editing may contribute to impaired hippocampal function after exposure to PRS. The efficacy of clozapine in improving SI behavior may include indirect stimulation of GluA2 RNA editing in the hippocampus. Although these data are from male mice and not humans, the results suggest a new molecular pathway by which PRS leads to life-long impairments of hippocampal function.

neuroscience↗