ERC FUNDED PROJECTS

Dysregulation of capillary permeability is a severe problem in critically ill patients, but the mechanisms involved are poorly understood. Further, there are no targeted therapies to stabilize leaky vessels in various common, potentially fatal diseases, such as systemic inflammation and sepsis, which affect millions of people annually. Although a multitude of signals that stimulate opening of endothelial cell-cell junctions leading to permeability have been characterized using cellular and in vivo models, approaches to reverse the harmful process of capillary leakage in disease conditions are yet to be identified. I propose to explore a novel autocrine endothelial permeability regulatory system as a potentially universal mechanism that antagonizes vascular stabilizing ques and sustains vascular leakage in inflammation. My group has identified inflammation-induced mechanisms that switch vascular stabilizing factors into molecules that destabilize vascular barriers, and identified tools to prevent the barrier disruption. Building on these discoveries, my group will use mouse genetics, structural biology and innovative, systematic antibody development coupled with gene editing and gene silencing technology, in order to elucidate mechanisms of vascular barrier breakdown and repair in systemic inflammation. The expected outcomes include insights into endothelial cell signaling and permeability regulation, and preclinical proof-of-concept antibodies to control endothelial activation and vascular leakage in systemic inflammation and sepsis models. Ultimately, the new knowledge and preclinical tools developed in this project may facilitate future development of targeted approaches against vascular leakage.

1 999 770 €

Start date: 2018-05-01, End date: 2023-04-30

B-cell malignancies are characterized by high levels of genomic instability, which critically contribute to their pathogenesis and evolution. Recently, the fundamental role of the ubiquitin proteasome system (UPS) in maintaining genome integrity has been appreciated. Two major new therapeutic modalities in B-cell malignancies, proteasome inhibitors and imunomodulatory drugs (IMiDs), target the UPS and demonstrate particular efficacy in multiple myeloma (MM) and mantle cell lymphoma (MCL), two incurable entities with poor prognosis. This suggests the presence of aberrant ubiquitylation events, whose identities have however remained mostly elusive. Our recent studies identify fundamental roles of orphan ubiquitin ligases of the Cullin Ring ligase family (CRLs) and their counterparts, the deubiquitylating enzymes (DUBs) in the cellular DNA damage response machinery, and characterize these candidates as novel oncogenes or tumour suppressors in MM and MCL. These findings provide the foundation for our hypothesis that deregulated ubiquitylation events involving CRLs and DUBs have a far reaching impact on the pathogenesis of B-cell malignancies and can serve as new therapeutic targets and biomarkers. We therefore propose a multistep strategy in which we will (1) characterize previously orphan CRLs and DUBs, which we have distinguished as candidate oncogenes and tumour suppressors in MM (FBXO3, USP24), MCL (FBXO25), or MM and MCL (CRBN), respectively; (2) decipher the global role of CRLs and DUBs in MM and MCL using defined genetic screens; (3) identify relevant substrates of CRLs/DUBs discovered in (2) using mass spectrometry; and (4) validate CRL/DUB candidates in preclinical mouse models and defined patient cohorts as to their disease relevance. We expect that our interdisciplinary approach will unravel the overall role of the UPS in the pathophysiology, evolution and treatment of B-cell malignancies.

1 973 255 €

Start date: 2016-09-01, End date: 2022-02-28

Introduction: Current anti-cancer treatments are often inefficient, while many patients initially benefit from anti-cancer drugs eventually experience relapse of resistant tumors throughout the body. Current clinical strategies mainly aim at inducing tumor cell death, but this induction may have unintentional and unwanted side effects on surviving tumor cells. Preliminary data: We show that after chemotherapy-induced initial regression, PyMT mammary tumors reappear. During regression, we observe an increased number of cells that have undergone epithelial-mesenchymal transition (EMT) and become migratory. We show that migration can be induced upon uptake of extracellular vesicles (e.g. apoptotic bodies). Our findings suggest that EMT is induced upon chemotherapy, through e.g. EV uptake, potentially leading to migration and growth of surviving cells. Hypothesis and main aim: Based on preliminary data, we hypothesize that tumor cell death induces migration and growth of the surviving tumor cells. We aim to identify the key cell types and mechanisms that mediate this effect, and establish whether interference with these cells and mechanisms can reduce recurrence of tumors after chemotherapy. Approach: We have developed unique intravital imaging tools and genetically engineered fluorescent mice to visualize and characterize if and how dying tumor cells can affect surrounding surviving tumor and stromal cells. We will test whether dying tumor cells can influence the growth, migration, dissemination and metastasis of surviving tumor cells directly or indirectly through stromal cells. We will identify potential targets to block the influence of the dying tumor cells, and test whether this blockade inhibits the unintended side-effects of tumor cell death. Conclusion: With the studies proposed in this grant, we will gain fundamental insights on how induction of tumor cell death, the universal aim of therapy, could play a role in growth and spread of surviving tumor cells.

2 000 000 €

Start date: 2015-09-01, End date: 2020-08-31

Contraction and relaxation of cardiac myocytes, and thus the whole heart, are critically dependent on dyads. These functional junctions between t-tubules, which are invaginations of the surface membrane, and the sarcoplasmic reticulum allow efficient control of calcium release into the cytosol, and also its removal. Dyads are formed gradually during development and break down during disease. However, the precise nature of dyadic structure is unclear, even in healthy adult cardiac myocytes, as are the triggers and consequences of altering dyadic integrity. In this proposal, my group will investigate the precise 3-dimensional arrangement of dyads and their proteins during development, adulthood, and heart failure by employing CLEM imaging (PALM and EM tomography). This will be accomplished by developing transgenic mice with fluorescent labels on four dyadic proteins (L-type calcium channel, ryanodine receptor, sodium-calcium exchanger, SERCA), and by imaging tissue from explanted normal and failing human hearts. The signals responsible for controlling dyadic formation, maintenance, and disruption will be determined by performing high-throughput sequencing to identify novel genes involved with these processes in several established model systems. Particular focus will be given to investigating left ventricular wall stress and stretch-dependent gene regulation as controllers of dyadic integrity. Candidate genes will be manipulated in cell models and transgenic animals to promote dyadic formation and maintenance, and reverse dyadic disruption in heart failure. The consequences of dyadic structure for function will be tested experimentally and with mathematical modeling to examine effects on cardiac myocyte calcium homeostasis and whole-heart function. The results of this project are anticipated to yield unprecedented insight into dyadic structure, regulation, and function, and to identify novel therapeutic targets for heart disease patients.

2 000 000 €

Start date: 2015-07-01, End date: 2020-12-31