Biology subjects

Guerrera, C.

Publications and source records attributed to Guerrera, C..

4 recordsLinked to original sources

bioRxiv2025

Piezo1 activation increases the release of therapeutic extracellular vesicles after mechanical stimulation in bioreactors

Enhancing protocols and methods for producing therapeutic extracellular vesicles (EVs) in bioreactors is crucial to achieve scalable production while ensuring both quality and quantity. Studies have shown that mechanical stress can promote EV release, although the underlying mechanisms remain largely unclear. Here we investigated which mechanisms are responsible for the increase of EV production under shear stress. EVs were produced from adipose tissue-derived stromal cells (ASCs), also described as mesenchymal stromal cells (MSCs) that can support the regeneration of injured tissues via several paracrine factors. The cultures were treated with GsMTx4, an inhibitor which blocks the Piezo1 ion channels, or with YODA1, its agonist, to assess if mechanical or shear forces pathways are involved in enhancing the EV release. EVs were quantified and characterized after high shear (HS) stimulation compared with no shear stress stimulation (3D) and standard cultures methods (2D). These experiments showed that, after mechanical stimulation by shear stress, EV production increased in bioreactors and this effect was blocked by the inhibition of Piezo1 ion channels with GsMTx4 (88%) with no impact on cell viability. Consistently, the agonist YODA1 increased the EV production (149%). The implications of these findings are significant, especially for regenerative medicine and cellular therapies, where the efficient production of high-quality EVs is crucial. By understanding turbulence-induced shear stress and the natural mechanotransductive pathways within cells, it may be possible to optimize the production of therapeutic EVs, paving the way for more effective treatments in the future.

cell biology↗

bioRxiv2023

mTOR Inhibition Suppresses Salinomycin-Induced Ferroptosis in Breast Cancer Stem Cells by Ironing Out Mitochondrial Dysfunctions

Ferroptosis constitutes a promising therapeutic strategy against cancer by efficiently targeting the highly tumorigenic and treatment-resistant cancer stem cells (CSCs). We previously showed that the lysosomal iron-targeting drug Salinomycin (Sal) was able to eliminate CSCs by triggering ferroptosis. Here, in a well-established breast CSCs model (human mammary epithelial HMLER CD24low/CD44high), we identified that pharmacological inhibition of mechanistic target of rapamycin (mTOR), suppresses Sal-induced ferroptosis. Mechanistically, mTOR inhibition modulates iron cellular flux and prevents the iron and ROS bursts induced by Sal. Besides, integration of multi-omics data identified mitochondria as a key target of Sal action. We demonstrated that mTOR inhibition prevents Sal-induced mitochondrial functional and structural alteration, and that Sal-induced metabolic plasticity is mainly dependent on the mTOR pathway. Overall, our findings provide experimental evidences on the detailed mechanisms of mTOR as a crucial effector of Sal-induced ferroptosis, and gives proof-of-concept that careful evaluation of such combination therapy (here mTOR and ferroptosis co-targeting) is required for effective treatment. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=120 SRC="FIGDIR/small/539040v1_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@8b8772org.highwire.dtl.DTLVardef@695e0forg.highwire.dtl.DTLVardef@19e3f83org.highwire.dtl.DTLVardef@5bc0a6_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2019

Reduced RNA turnover as a driver of cellular senescence

Accumulation of senescent cells is an important contributor to chronic inflammation upon aging. While cytoplasmic DNA was shown to drive the inflammatory phenotype of senescent cells, an equivalent role for RNA has never been explored. Here, we show that some senescent cells accumulate long promoter RNAs and 3 gene extensions, rich in retrotransposon sequences. Accordingly, these cells display increased expression of genes involved in detecting double stranded RNA of viral origin downstream of the interferon pathway. The RNA accumulation is correlated with signs of reduced RNA turn-over, including in some cases, reduced expression of RNA exosome subunits. Reciprocally, engineered inactivation of RNA exosome subunit Exosc3 induces expression of multiple senescence markers. A senescence-like RNA accumulation is also observed in cells exposed to oxidative stress, an important trigger of cellular senescence. Altogether, we propose that in a subset of senescent cells, repeat-containing transcripts stabilized by oxidative stress or reduced RNA exosome activity participate, possibly in combination with cytoplasmic DNA, in driving and maintaining the permanent inflammatory state characterizing cellular senescence.

molecular biology↗

bioRxiv2018

BIN1 genetic risk factor for Alzheimer is sufficient to induce early structural tract alterations in entorhinal cortex-dentate gyrus pathway and related hippocampal multi-scale impairments

Genetic factors are known to contribute to Late Onset Alzheimers disease (LOAD) but their contribution to pathophysiology, specially to prodomic phases accessible to therapeutic approaches are far to be understood. To translate genetic risk of Alzheimers disease (AD) into mechanistic insight, we generated transgenic mouse lines that express a [~]195 kbp human BAC that includes only BIN1, a gene associated to LOAD. This model gives a modest BIN1 overexpression, dependent of the number of BAC copies. At 6 months of age, we detected impaired entorhinal cortex (EC)-hippocampal pathways with specific impairments in EC-dentate gyrus synaptic long-term potentiation, dendritic spines of granular cells and recognition episodic memory. Structural changes were quantified using MRI. Their whole-brain functional impact were analyzed using resting state fMRI with a hypoconnectivity centered on entorhinal cortex. These early phenotype defects independent of any changes in A-beta can be instrumental in the search for new AD drug targets.

neuroscience↗