Deletion of IL-4Rα signalling on B cells limits hyperresponsiveness depending on antigen-load.

B cells play an important role in allergies through secretion of IgE. Interleukin 4 50 receptor α (IL-4Rα) is key in allergic asthma and regulates type 2 cytokine production, IgE 51 secretion and airway hyperresponsiveness (AHR). IL-4 activation of B cells is essential for 52 class-switching and contributes to the induction of B effector 2 (Be2) cells. The role of Be2 53 cells and signalling via IL-4Rα in B cells is not clearly defined

Investigating role of IL-4 receptor alpha (IL-4Ra) in murine models of atopic dermatitis

Atopic dermatitis (AD) is a common pruritic inflammatory skin disease with complex environmental and genetic predisposition factors. Primary skin barrier dysfunction and aberrant T helper 2 (TH2) responses to common allergens, together with increased serum IgE antibodies, characterise the disease. B and T cells are essential in the disease manifestation, however, the exact mechanism of how these cells are involved in skin sensitization to allergens is unclear. Clinical studies investigating the efficacy of monoclonal antibody to IgE such as omalizumab and ligelizumab do not show efficacy in AD patients. However, targeting IL-4/IL-13 signalling axis with dupilumab show efficacy in AD. We investigated the importance of interleukin 4 receptor alpha (IL- 4Rα) signalling specifically on B and T cells to understand the requirement of this signalling axis in epicutaneous skin sensitisation during AD. We investigated 3 models of AD using House dust mite (HDM), Ovalbumin (OVA) and low-calcemic analog of vitamin D (MC903) on mouse strains lacking IL-4Ra on various B and T cells. We used mb1creIL-4Rα-/lox (mice lacking IL-4Rα on B cells), iLcKCre IL-4Rα-/lox (mice lacking IL-4Rα on all T cells), LcKCre IL-4Rα-/lox (mice lacking IL-4Rα on CD4+ and CD8+ T cells), CD4Cre IL-4Rα-/lox (mice lacking IL-4Rα on CD4+ Tcells), Foxp3Cre IL-4Rα-/lox (mice lacking IL-4Rα on Foxp3+ T regulatory cells) and IL-4Rα-/lox littermate controls. We analysed cellular infiltrate in the skin and inguinal lymph nodes (LN) by flow cytometry, histology of the skin, serum antibodies and cytokines by ELISA. Mice lacking IL-4Rα-responsive B cells showed a reduced serum IgE levels, but no significant differences in epidermal thickening compared to littermate control in HDM or MC903 models. Mice investigated in the T cell arm of the study showed reduced epidermal thickening in pan-T cell IL-4Rα knock-out, but not in groups lacking IL-4Rα signalling in adaptive T cells, suggesting importance of IL4/IL13 signalling axis in ydT cells during AD. Overall, our results suggest that deletion of IL-4Rα on innate T cells regulates inflammatory response in atopic dermatitis

Short Stimulation of Electro-Responsive PAA/Fibrin Hydrogel Induces Collagen Production

Acrylic acid/fibrin hydrogel can mechanically stimulate cells when an external electrical field is applied, enabling them to migrate and align throughout the depth of the gel. The ability of electro-responsive polyacrylic acid (PAA)/fibrin hydrogel to promote collagen production and remodeling has been investigated by three-dimensional (3D) culturing and conditioning of smooth muscle cells (SMCs). SMCs-seeded hydrogels were subjected to an alternating electrical field (0.06 V/mm) for 2 h for one, two, or three times per week during 4 weeks of culturing. Fluorescent images of collagen structure and accumulation, assessed by CNA-35 probe, showed increased collagen content (>100-fold at 1× stimulation/week) in the center of the hydrogels after 4 weeks of culture. The increase in collagen production correlated with increasing extracellular matrix gene expression and resulted in significantly improved mechanical properties of the stimulated hydrogels. Matrix metalloproteinase (MMP)-2 activity was also significantly enhanced by stimulation, which probably has a role in the reorganization of the collagen. Short stimulation (2 h) induced a favorable response in the cells and enhanced tissue formation and integrity of the scaffold by inducing collagen production. The presented set up could be used for conditioning and improving the functionality of current tissue-engineered vascular grafts