Despite the emergence of innovative therapeutic solutions in recent years, there is still a need for further research on strategies to reduce plasma low-density lipoprotein cholesterol levels, as a significant proportion of patients do not achieve their cholesterol reduction goals and remain at risk of developing atherosclerotic cardiovascular disease. Recently, we characterized the second genetic cause of familial combined hypocholesterolemia by discovering a gain of function mutation in the LIPC gene encoding for hepatic lipase. This LIPC-E97G variant alters the structural conformation of the enzyme and strongly increases its phospholipase activity. Interestingly, its ectopic expression in humanized APOE*3.Leiden.CETP mice mimics the human lipid phenotype and leads to a rapid and sustainable reduction of plasma phospholipids, triglycerides and cholesterol levels. The three main objectives of this proposal are: 1) To identify & characterize new LIPC variants in cohorts of patients with undefined origin of extremely low plasma cholesterol levels 2) To understand the mode of action & pathways involved in the lipid lowering effects of LIPC E97G 3) To evaluating the pro- or anti-atherogenic properties of E97G LIPC variant in human and mice Further deciphering the mechanism of action of E97C LIPC variant is of critical importance because: 1) this allows the characterization of a new LDL receptor-independent lipoprotein catabolism pathway; 2) this highlights the importance of the under-explored phospholipase activity in lipoprotein homeostasis; 3) this opens up a new therapeutic target for the treatment of severe hypercholesterolemia.

Shock situations (whether hemorrhagic or septic) share common pathophysiological mechanisms (implementation of inflammatory processes, cardiovascular failures, hypoperfusion of peripheral organs, etc.) that require rapid and appropriate management. They are both associated with high morbidity and mortality with a cost to society that increases each year. Unfortunately, the available treatments are very limited and mainly target symptoms. All recent studies have failed, we are facing a therapeutic impasse. It is therefore urgent to develop new strategies for new targets. In this context, our project aim to develop new approaches. In collaboration with JC Chatham (University of Birmingham, Alabama, US), we have developed an approach to stimulate O-GlcNAcylation[2] in hemorrhagic shock or septic shock. O-GlcNAcylation is a post-translational modification responsible for cell survival that plays a major role in the cell response to stress. The approaches developed by our two teams aim to increase O-GlcNAc levels very early on, and are associated with a significant reduction in stress markers, an improvement in cardiovascular function and a significant reduction in mortality in both types of shock. They demonstrate that the stimulation of O-GlcNAcylation has significant therapeutic potential for patient survival and on the battlefield to limit the damage associated with shock situations. The consortium we have built with the chemists of the Ceisam team (univ Nantes), JC Chatham and the IIb team of the Thorax Institute will enable us to develop a stable molecule, injectable intramuscularly or intravenously with targeting properties. With this funding, we hope to ensure its safety and validate its efficacy at different times / dose in order to quickly offer injectable treatment to patients and on the battlefield to reduce the morbidity and mortality associated with hemorrhagic and septic shock.

Channelopathies induce severe heart rhythm or conduction disorders. Mutations of the KCNH2 gene, that encodes the human (h) ERG channel, is responsible for 30% of all cases of long QT syndrome. Besides, hERG is frequently responsible for off-target effects of several pharmacological agents. With the advent of Next Generation Sequencing, hundreds of new KCNH2 variants are accumulating in various databases, many being of unknown significance to clinicians which hampers the value of their diagnosis and the quality of patient management. Therefore, there is an urgent need to functionally characterize a large fraction of KCNH2 variants and provide access of this information to hospital clinicians. We assembled a consortium of clinicians, geneticists, biophysicists and computer bioscientists to build the largest web-accessible diagnostic/prognostic database of hERG-related channelopathies. To this end, we will take advantage of high-throughput techniques of channel variant phenotyping.

The function of a channel in a neuron relies on the synergistic activity of several different ion channels in the system during physiological activity, as these determine the membrane potential and the intracellular calcium. Yet, the interplay of the diverse channels underlying a physiological signal is unknown and this information can be extracted only by quantitative analysis of a rich experimental dataset taking into account the role of each individual channel. This project aims at developing novel technologies to address the challenge of investigating multiple activations of different ion channels in native systems, which should lead to a better understanding of how mutations of a channel translate into global pathological signals. To achieve this goal, we propose to develop several photoactivable toxins (TASK 1) and an original software based on NEURON (TASK 2) to be used for analyses of data generated with our cutting-edge optical techniques, permitting the reconstruction of all ionic currents involved in a physiological signal. The successful photoactivable toxins will be protected by IP and industrialized contacts, such as Smartox Biotechnology (https://www.smartox-biotech.com/) may be interested for commercialization under a licence agreement. We will initially develop at least six functional photoactivable toxins selective for some of the most relevant neuronal channels and, at a second stage, other toxins according to the evolution of the project. All toxins will be first assessed in terms of photochemical properties, in vitro efficacy for light-induced current blockage, and later for application in brain slices exploiting our expertise in caged compound characterisation. The NEURON-based software will be developed in collaboration (not funded by the ANR) with the ERC-laureate team of Panayiota Poirazi (http://www.dendrites.gr/). We will first produce detailed membrane potential and Ca2+ optical recordings at high temporal resolution using cutting-edge technologies developed in previous ANR projects, dissecting single channel contributions using toxins. Then, we will produce models of neuronal compartments with realistic channels matching the complexity of experimental scenarios and these models will be deposited in the ModelDB database (https://senselab.med.yale.edu/ModelDB/). These tasks will lead to a unique strategy for the analysis of signal dysfunction in animal models of channelopathies (TASK 3). We will deliver an original method to tackle the pivotal question in the study of channelopathies: how the dysfunction of a particular channel can change the function of the other channels to eventually translate in the distortion of a signal underlying brain disorder. The project will be coordinated by the team of Marco Canepari (http://marco-canepari.wix.com/neuron-imaging-team), exploiting his expertise in functional imaging applied to ion channels research in neuroscience. The task of photoactivable toxins development will be devoted to the team of Michel De Waard (http://www.umr1087.univ-nantes.fr/nos-equipes/equipe-iib-insuffisance-cardiaque-et-approches-pharmacologiques-1518040.kjsp?RH=1331825361673) who is leader in cell penetrating peptides for biotechnological applications and in animal toxins, but also the founder of Smartox Biotechnology. Both teams belong to the French LABEX Ion Channels, Science and Therapeutics (ICST, http://www.labex-icst.fr/en) and other teams of the consortium will benefit of this novel strategy in projects investigating channelopathies of the nervous system. We also aim at using this project as kick off for a larger research European program to merge the excellence of French laboratories in experimental technologies to investigate ion channels with the expertise of European teams in computational neuroscience. The longer term goal is to generate a database of native kinetics models of ion channels to explore the channel dysfunctions underlying brain diseases.

Intracranial aneurysms (IAs) affect 3% of the population and IA rupture is a devastating event (40% mortality). The ICAN biobank includes 3400 IA patients with clinical, imaging and DNA. WECAN relies on this exceptional resources for rupture risk stratification among IAs. WP1 uses image processing tools for automatic and morphological characterization of the brain vessels. This will allow an objective characterization of IA. WP2 exploits the whole ICAN population by sequencing a panel of susceptibility genes and genotyping SNPs.WP3 crosses multimodal data to build a predictive model of IA sub-phenotypes and stratify the risk of IA rupture. Quantitative traits extracted from imaging will be cross-analyzed through advanced deep learning strategies with the clinical and genetics data. This strategy has never been performed to date for IAs. The IA pathology will benefit from personalized, precision medicine and FAIR big data analysis, leveraging open science best practices.