Sepsis exemplifies a complex clinical syndrome that results from a harmful and damaging host response to severe infection. Sepsis develops when the initial, appropriate host response to systemic infection becomes amplified and then dysregulated. One of the amplifiers of the inflammatory response is the Triggering Receptor Expressed on Myeloid cells-1 (TREM-1). Indeed, TREM-1 and TLRs appear to cooperate in a synergistic way. The role of TREM-1 as an amplifier of the immune response has been confirmed in a mouse model of septic shock in which blocking signaling through TREM-1 partially protected animals from death. TLT-1 (TREM Like Transcript-1) is a platelet specific receptor that belongs to the TREM family. The recent characterization of the TLT-1 extracellular domain has uncovered evidence that suggests a role of TLT-1 during the onset and progression of sepsis. Indeed, we have shown that TLT-1 and a TLT-1 derived peptide, LR17, exhibit anti-inflammatory properties by dampening TREM-1 signaling and thus behave as a naturally occurring TREM-1 inhibitor. LR17 decreased in vitro TREM-1- and LPS-induced neutrophil activation (intracellular signaling, NFkB activation, cytokine production, ROS production, etc), acting like a decoy receptor and competing against TREM-1 receptor. As a result of this activity, both early and late LR17 administration to septic mice modulate in vivo the proinflammatory cascade triggered by infection, thus preventing from hyper-responsiveness, organ damage and coagulation abnormalities, and finally improve survival (by more 60% vs controls). The aim of the current proposal is to optimize LR17 sequence (length, kinetics, etc) and complete preclinical study. First, we want to reduce LR17 length and then optimize its stability by evaluating its pharmacokinetics/dynamics (PK/PD) properties and toxicity in vitro and in vivo, and in fine optimize therapeutic doses. We also propose to evaluate the protective effect of LR17 during sepsis in non-murine species (pig). This LR17 peptide is already the subject of an invention submission process in collaboration with Inserm Transfert. This project should lead to the creation of Biotech Company.

Plasma concentrations of HDL cholesterol (HDL-C) and its major protein component apolipoprotein (Apo) A-I are strongly inversely associated with cardiovascular risk, leading to the concept that therapy to increase HDL-C and ApoA-I concentrations would be antiatherosclerotic and protective against cardiovascular events. The protective effect of HDL is mostly attributed to its central function in reverse cholesterol transport (RCT), a process whereby excess cell cholesterol is taken up and processed in HDL particles, and is later delivered to the liver for further metabolism and bile excretion. The recent failure of the drug torcetrapib, a cholesteryl ester transfer protein inhibitor that substantially increased HDL-C concentrations, has brought focus on the issues of HDL function in promoting RCT as distinct from HDL-C concentrations. Therefore, robust laboratory assays of HDL functions and/or rate of RCT and validation of the usefulness of these assays for predicting cardiovascular risk and assessing response to therapeutic interventions are critically important and of great interest to cardiovascular clinicians and investigators and clinical chemists. In this context, we have identified the F1-ATPase-mediated HDL pathway as a new pathway promoting the last step of RCT (i.e. hepatic HDL-C removal). Furthermore, we have recently found that the natural inhibitor IF1 of F1-ATPase, usually expressed in mitochondria, was also circulating in human and mice blood. Since our previous studies observed that exogenous recombinant IF1 could inhibit the F1-ATPase-mediated HDL pathway both on cellular models and on IF1-perfused rat liver, we hypothesized here that the circulating form of IF1 could constitutively modulate HDL metabolism and that its quantification in serum could be useful for predicting cardiovascular risk and assessing response to therapeutic interventions. This hypothesis was partly confirmed by our preliminary data showing a positive correlation between circulating IF1 and HDL levels in a cohort of 275 male subjects taken from the general population. In this project, we propose: 1) To explore in a large control-case epidemiological study the relevance of circulating IF1 level in the evaluation of the cardiovascular risk. 2) To explore the role of IF1 in experimental models of RCT and atherogenesis 3) To standardize ELISA Assay for IF1 quantification in serum and elaborate therapeutic approaches The overall objective is to validate IF1 as a new biological circulating marker that reflects the functionality of HDL and not only their circulating level and might be better predictor of cardiovascular risk. This might lead to the development of a new kit for functional HDL levels that may be used in clinical biochemistry laboratories for predicting of cardiovascular risk and treatment’s choice. Finally, regarding the highly competitive field of HDL therapy, this research project might conduce to the discovery of a new way increasing functional HDL, for the development of new drugs as a treatment for cardiovascular disease.

Diseases of the heart and the cardiovascular system are the leading cause of mortality in France, accounting for >180 000 deaths per year. Their incidence is expected to increase further in the next five decades due to rising life expectancy, obesity and type II diabetes in the general population. To achieve a further substantial drop in cardiovascular morbidity and mortality in the future, entirely new diagnostic avenues need to be opened up based on the detection of individuals who are at risk of developing cardiovascular diseases in order to facilitate preventive approaches. Activation or apoptosis of endothelial cells lining blood vessels is a crucial early event in the development of cardiovascular diseases and we and other groups have previously shown that remnants of this endothelial activation are found in human plasma as circulating shed-membrane microparticles (MPs) of endothelial origin and that their levels are independently associated with altered vascular function in patients with cardiovascular diseases. In addition, we and other groups demonstrated the prognostic role of endothelial MPs for cardiovascular mortality and major events in populations of patients with cardiovascular disease, and filed a European Patent Application on July 1st, 2009 (EP09305635) proposing MPs as a new measure of cardiovascular mortality risk. Our first goal is to develop high throughput measure of plasma EMP levels to analyze large numbers of samples and accelerate the transfer of this technology from a research laboratory to routine biological facilities or laboratory test companies. The second aim of this study is to monitor the added value of measuring circulating endothelial MPs as a prognostic marker for cardiovascular risk assessment in 2000 subjects from the Framingham Heart Study, a well-characterized and widely cited human population. This research will contribute to improving cardiovascular risk assessment in the general population and is likely to impact on healthcare decisions, as established risk factors and the use of contemporary biomarkers do not fully predict cardiovascular risk.