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Feliziani, C.

Publications and source records attributed to Feliziani, C..

2 recordsLinked to original sources

Genotype-specific roles of small extracellular vesicles in modulating metronidazole resistance in Giardia lamblia

Giardia lamblia, a eukaryotic intestinal parasite, produces small extracellular vesicles (sEVs) as a conserved evolutionary mechanism. This study investigates the functional role of sEVs in transferring drug-resistance traits among parasites. sEVs derived from metronidazole (MTZ)-resistant clones are shown to modify the expression of enzymes involved in MTZ metabolism and the production of reactive oxygen species (ROS) in recipient wild-type parasites. These changes significantly alter the drug sensitivity of recipient parasites. The transfer efficiency and phenotypic impact vary depending on the genetic background of the isolates, highlighting a genotype-specific mechanism. Our findings reveal that sEVs act as mediators of phenotypic adaptation in G. lamblia, enhancing parasite survival under drug-induced stress. This study underscores the importance of sEVs in drug-resistance dynamics and provides a basis for exploring therapeutic interventions targeting EV-mediated resistance in giardiasis. Highlights In briefO_LISmall extracellular vesicles (sEVs) from Giardia lamblia mediate genotype-specific MTZ resistance transfer. C_LIO_LISmall extracellular vesicles from drug-resistant clones (RsEVs) alter enzyme expression and reactive oxygen species (ROS) production in recipient trophozoites. C_LIO_LIThe genetic background of G. lamblia isolates influences the effectiveness of resistance transfer. C_LIO_LIFindings provide insights into resistance mechanisms and potential targets for new giardiasis therapies. C_LI

cell biology↗

Endoplasmic reticulum stress induces a novel Ca2+ signalling system initiated by Ca2+ microdomains

The accumulation of unfolded proteins within the Endoplasmic Reticulum (ER) activates a signal transduction pathway termed the unfolded protein response (UPR), which attempts to restore ER homeostasis. If homeostasis cannot be restored, UPR signalling ultimately induces apoptosis. Ca2+ depletion in the ER is a potent inducer of ER stress. Despite the ubiquity of Ca2+ as intracellular messenger, the precise mechanism (s) by which Ca2+ release affects the UPR remains unknown. Use of a genetically encoded Ca2+ indicator (GCamP6) that is tethered to the ER membrane, uncovered novel Ca2+ signalling events initiated by Ca2+ microdomains in human astrocytes under ER stress, as well as in a cell model deficient in all three IP3 Receptor isoforms. Pharmacological and molecular studies indicate that these local events are mediated by translocons. Together, these data reveal the existence of a previously unrecognized mechanism by which stressor-mediated Ca2+ release regulates ER stress.

cell biology↗