Meeting in the Middle: Towards Successful Multidisciplinary Bioimage Analysis Collaboration

With an increase in subject knowledge expertise required to solve specific biological questions, experts from different fields need to collaborate to address increasingly complex issues. To successfully collaborate, everyone involved in the collaboration must take steps to "meet in the middle". We thus present a guide on truly cross-disciplinary work using bioimage analysis as a showcase, where it is required that the expertise of biologists, microscopists, data analysts, clinicians, engineers, and physicists meet. We discuss considerations and best practices from the perspective of both users and technology developers, while offering suggestions for working together productively and how this can be supported by institutes and funders. Although this guide uses bioimage analysis as an example, the guiding principles of these perspectives are widely applicable to other cross-disciplinary work

Absence of MHC-II expression by lymph node stromal cells results in autoimmunity.

How lymph node stromal cells (LNSCs) shape peripheral T-cell responses remains unclear. We have previously demonstrated that murine LNSCs, lymphatic endothelial cells (LECs), blood endothelial cells (BECs), and fibroblastic reticular cells (FRCs) use the IFN-γ-inducible promoter IV (pIV) of the MHC class II (MHCII) transactivator CIITA to express MHCII. Here, we show that aging mice (>1 yr old) in which MHCII is abrogated in LNSCs by the selective deletion of pIV exhibit a significant T-cell dysregulation in LNs, including defective Treg and increased effector CD4 <sup>+</sup> and CD8 <sup>+</sup> T-cell frequencies, resulting in enhanced peripheral organ T-cell infiltration and autoantibody production. The proliferation of LN-Tregs interacting with LECs increases following MHCII up-regulation by LECs upon aging or after exposure to IFN-γ, this effect being abolished in mice in which LECs lack MHCII. Overall, our work underpins the importance of LNSCs, particularly LECs, in supporting Tregs and T-cell tolerance

MHCII mediated antigen-presentation by lymph node stromal cells in autoimmunity and cancer

Lymph nodes stromal cells (LNSCs) modulate the functions of hematopoietic antigen-presenting cells (APCs) and impact T cell homeostasis. LNSCs can ectopically express peripheral tissue-restricted antigens and present them through MHCI to induce self-reactive CD8+ T cell deletion. To study their role as MHCII-restricted APCs, we used a mouse model where MHCII was abrogated in LNSCs. Aging mice developed spontaneous autoimmunity, including enhanced T cell activation, autoantibodies, and T cell infiltration in peripheral organs. Our data highlight a tolerogenic impact of MHCII-mediated self-antigen presentation by LNSCs on CD4+ T cells in autoimmunity. However, mechanisms of immune suppression can lead to pathogens or tumors escaping immune responses. A second axis of our investigations was to determine whether tumor associated LNSCs present tumor antigens through MHCII and modulate tumor specific CD4+ T cell responses. Our preliminary data indicate that tumor associated LNSCs support immunosuppression, promote tumor growth and that MHCII-tumor antigen presentation has pro-tumoral functions. Our project revealed crucial new insights about a role of antigen-presenting LNSCs in peripheral T cell tolerance, a concept that will significantly impacts strategies to modulate their function in cancer and autoimmunity