P17.03.B Modelling migration of glioblastoma patient-derived cells using human iPSC-derived neural spheroid and high content analysis

Background

Glioblastoma multiforme (GBM) is the most common and aggressive brain tumour in adults. Despite current advances, the existing standard of treatment is ineffective, and the survival prognosis remains just over a year from diagnosis. Migrating tumour cells have been implicated in the therapeutic resistance of GBM. They spread by interacting with structures such as white matter tracts and inevitably cause recurrence of the tumour. Valuable cell models able to capture the invasiveness of GBM are critically needed to develop innovative therapies targeting migrating GBM cells.

Material and Methods

We established an in vitro model mimicking the GBM microenvironment by co-culturing patient-derived GBM cells and human induced pluripotent stem cell-derived cortical neural spheroids with radiating axons. Using high content imaging, we developed a robust workflow to quantify the GBM cells infiltration of the neural spheroid in endpoint assays. Images were acquired on the Operetta CLS high content device (Perkin Elmer) and analysed using the built-in Harmony Imaging and Analysis Software. We also performed live imaging assays using the Livecyte quantitative phase imager (Phasefocus), in which we studied the directionality, displacement and speed of the GBM cells engaged on axons.

Results

Our data indicate that GBM cells change morphology when cultured on axons and that they migrated towards the neural spheroid once engaged on axons. We showed that cell lines from different patients vary in migratory properties as well as in levels of infiltration capability. Finally, we used this model to test several antagonists to pathways involved in migration of GBM cells.

Conclusion

The main deliverable of this project is the setup of a novel model able to mimic the GBM migration on axons and able to screen for compounds affecting cell migration. This could potentially offer innovative precision-medicine therapies.

The transCampus Metabolic Training Programme Explores the Link of SARS-CoV-2 Virus to Metabolic Disease

Currently, we are experiencing a true pandemic of a communicable disease by the virus SARS-CoV-2 holding the whole world firmly in its grasp. Amazingly and unfortunately, this virus uses a metabolic and endocrine pathway via ACE2 to enter our cells causing damage and disease. Our international research training programme funded by the German Research Foundation has a clear mission to train the best students wherever they may come from to learn to tackle the enormous challenges of diabetes and its complications for our society. A modern training programme in diabetes and metabolism does not only involve a thorough understanding of classical physiology, biology and clinical diabetology but has to bring together an interdisciplinary team. With the arrival of the coronavirus pandemic, this prestigious and unique metabolic training programme is facing new challenges but also new opportunities. The consortium of the training programme has recognized early on the need for a guidance and for practical recommendations to cope with the COVID-19 pandemic for the community of patients with metabolic disease, obesity and diabetes. This involves the optimal management from surgical obesity programmes to medications and insulin replacement. We also established a global registry analyzing the dimension and role of metabolic disease including new onset diabetes potentially triggered by the virus. We have involved experts of infectious disease and virology to our faculty with this metabolic training programme to offer the full breadth and scope of expertise needed to meet these scientific challenges. We have all learned that this pandemic does not respect or heed any national borders and that we have to work together as a global community. We believe that this transCampus metabolic training programme provides a prime example how an international team of established experts in the field of metabolism can work together with students from all over the world to address a new pandemic.

The murine beta-chemokine TARC is expressed by subsets of dendritic cells and attracts primed CD4+ T cells

To investigate specific properties of dendritic cells (DC) which are not shared by other antigen-presenting cells, we compared gene expression patterns of mouse DC and macrophages by differential mRNA display. One of the cDNA identified coded for a murine homolog of the human beta-chemokine, thymus and activation-regulated chemokine (TARC). The gene is expressed in a subset of bone marrow-derived DC and is up-regulated after lipopolysaccharide (LPS) stimulation. In vivo, murine TARC (mTARC) is constitutively expressed by thymic DC, lymphnode DC and CD11c+ cells in the lung. No expression was detected in bone marrow-derived macrophages and LPS-activated B cells. Recombinant mTARC has no chemoattractant activity on naive peripheral CD4+ T cells. In contrast, mTARC induced migration of primed ovalbumin-specific CD4+ T cells with a preference for Th2 cells during the early phase of the T cell response. These observations suggest that mTARC directs migration of antigen-experienced T helper cells to DC in lymphoid as well as in non-lymphoid organs.

Peripheral tolerance of CD4 T cells following local activation in adolescent mice

In addition to thymic T cell selection, post-thymic mechanisms of tolerance induction are required to eliminate autoreactive T cells with specificities for peripheral self antigens. While CD8+ T cells can recognize their target antigen on a wide variety of cell types, CD4+ T cells generally depend on the presence of specialized antigen-presenting cells. Because of this fundamental difference in antigen recognition peripheral tolerance of CD4+ T cells appears more difficult to achieve than of CD8+ T cells. Utilizing T cell receptor (TCR)-transgenic mice in which CD4+ T cells specific for a pancreatic beta cell neoantigen (the simian virus 40 T antigen) are constantly generated at low frequency, we have now established a mouse model of peripheral, tissue-specific CD4+ T cell tolerance. In these animals, tolerance is preceded by a phase of activation of the autoreactive T cells as characterized by up-regulation of CD69 and CD44, and down-regulation of the L-selectin lymph node homing receptor. T antigen-specific T cells bearing this phenotype can be detected in the local lymphoid environment of the pancreas but not in more remote locations like axillary or inguinal lymph nodes. The proportion of activated, autoreactive T cells is maximal at 2-3 weeks of age, after which these cells are gradually deleted from the peripheral lymphocyte pool. We further demonstrate that deletion of the autoreactive T cells does not occur in TCR-transgenic mice bred to the RAG-1-deficient background in which the transgenic T cells represent the only functional lymphocyte population.