Laminin-2 immobilized on a 3D fibrous structure impacts cortical thymic epithelial cells behaviour and their interaction with thymocytes

The tri-dimensionality of the thymic extracellular matrix (ECM) supports the crosstalk between thymocytes and thymic epithelial cells (TECs). The thymic ECM component laminin-2 is involved in the regulation of thymocytes and their interaction with cortical TECs (cTECs). Most in vitro studies use planar surfaces to study the interaction between ECM components and thymic cells. Herein, we developed a novel biofunctionalized culture system by immobilizing laminin-2 at the surface of porous and fibrous electrospun meshes. We aimed to study the interaction of cTECs with thymocytes in the presence of laminin-2 presented through this system. The results indicated that the presence of laminin-2, not its density, has a positive effect on the cell viability and proliferation of cTECs. qPCR results demonstrated that laminin-2 density influenced the expression of cTECs genes. An increased percentage of adherent CD4−CD8− thymocytes and a decreased percentage of CD4+CD8+ thymocytes were evident in higher laminin-2 concentrations. Higher concentrations decreased the expression of Il7 and Ccl25 in cTECs after thymocyte adhesion. Altogether, these results indicate that the interaction of thymocytes with the thymic cortical compartment is affected by laminin-2 density and supports the need for immobilized ECM proteins in porous and fibrous substrates for the study of thymus biology.