Pause-conférence | Les membres du CERMO-FC

Pause-conférence | Les membres du CERMO-FC

Ul24 du virus herpès simplex 1 régule à la baisse l’expression d’oligoadenylate synthetase-like en contexte d’infection

Fernando Sánchez Quete, candidat au M.Sc. dans le laboratoire de la Pre Angela Pearson à l’Université INRS

Résumé:
La réponse immunitaire innée contre le virus herpès simplex 1 (HSV-1) est critique pour prévenir l’encéphalite due à ce virus.  Cette réponse comprend, entre autres, la détection du génome viral par le senseur d’ADN cGAS. L’activation de cGAS mène à la production des interférons (IFNs) et l’expression en aval des ISGs (IFN-stimulated genes) qui déclenchent l’état antiviral. Cependant, le HSV-1 induit l’ISG OASL qui, dans le cas de virus à ADN, a un effet proviral dû au fait que l’OASL bloque cGAS. Cette induction est suivie d’une régulation à baisse dans un temps tardif de l’infection dont le mécanisme est inconnu. Le gène viral UL24 est impliqué dans l’évasion immunitaire et la pathogenèse. Nous avons donc testé l’impact de celui sur l’expression d’OASL. Nos résultats supportent un modèle où l’OASL est induite d’une manière UL24-indépendente dès 5 heures post infection (hpi) et ensuite modulée à la baisse d’une manière UL24-dépendente à 12 hpi via IRF3. De plus, les niveaux des transcrits de l’IFN-β et des ISGs (CXCL10 et ISG54) sont consistants avec ce modèle, et l’effet d’OASL sur cGAS. Nos résultats montrent la fonction immunomodulatrice d’UL24 dans l’infection par HSV-1.

Mammary gland in a petri dish. Biologically representative alternative models

Melany Juárez Velázquez, candidate au M.Sc. dans le laboratoire de la Pre Isabelle Plante à l’Université INRS

Résumé:
The functional unit of the mammary gland is the bilayered acinus, composed of an inner layer of polarized luminal epithelial cells and an outer layer of myoepithelial cells. Evidence has shown that the in vivo tridimensional (3D) environment and the bidirectional crosstalk between cells are crucial for proper function, development and differentiation of the mammary gland.  Our project aims to develop a representative model in vitro of the interactions between luminal and myoepithelial cells of the mammary gland. This is achieved by establishing a 3D bilayered co-culture model and a 2D layered co-culture model using both types of cells. Both the composition of the extracellular matrices and of the types cell lines were optimized. Our results show that co-cultured luminal MCF-12A and myoepithelial-like Myo1089 human cells, in Matrigel, form bilayered acini. Similarly, when luminal MCF-12A cells and myoepithelial-like Hs578Bst cells are co-cultured in Matrigel, few bilayered acini are formed. However, monolayered acini made of only luminal cells were abundant. Notably, these 3D models closely mimic the structure of the bilayered acini observed in vivo, thus suggesting that they could represent an acceptable in vitro surrogate to the in vivo animal models.

In parallel, MCF-12A and Myo1089 cells were co-culture, each on a different side of inserts with porous membranes to create a layered cultured system. Our results have demonstrated that cells seeded on each side of the membrane can communicate via gap junctions, as demonstrated by dye transfer assays using calcein and DiL. Immunofluorescence analysis suggested that junctions are formed between luminal and myoepithelial cells likely through cell projections within the pores of the membrane. Future experiments will aim to evaluate the impact of bidirectional crosstalk on cell signaling in each cell type. We expect that our innovative in vitro models will provide a more biologically relevant option for fundamental research in the development of mammary gland and the mechanisms of pathologies, as well as in toxicology studies. Accordingly, filling the gap between results obtained from laboratory models and the expected results from animal testing through mimicking the structure, the communication and the composition of the human mammary gland.

Un évènement organisé dans le cadre des Pause-conférences du CERMO-FC et soutenu par :
An event organized as part of the Pause-conférences of CERMO-FC, and support by :