The interstitial fibrosis is a major health problem because it causes dysfunction of many organs and is responsible for a high degree of morbidity and mortality due to organ injury. The frequency of pathologies with fibrosis increases progressively due to aging of the population and increase in risk factors due to occidental way of life. In this way, chronic kidney disease (CKD) is one of the pathologies associated with fibrosis, leading to renal dysfunction and to end stage renal disease. However, until now, no specific biomarker and no treatment are available,requiring to further study the molecular regulation of renal fibrosis. Our hypothesis is that soluble CD146 (sCD146), a new growth factor secreted abundantly during CKD, is involved in the development of interstitial fibrosis. The objective of our project will thus be to delineate the contribution of sCD146 to kidney fibrosis development, to evaluate its diagnostic interest as a biomarker, and to test newly generated anti-sCD146 antibodies as a new therapeutic approach.

Renal diseases can be progressively complicated by Chronic kidney diseases (CKD), whatever the initial renal injury. CKD represent a worldwide health concern: about 10%-15% of the overall population is affected by CKD worldwide and this number is expected to increase. CKD has also dramatic consequences in patient’ morbidity and mortality, including cardiovascular morbidity. Glomerular injuries are a major cause of CKD (leading to 30% incident dialysis cases each year in France). Among glomerular injuries, the most severe forms are glomerulonephritis with extracapillary proliferation, leading to nephron loss and end stage renal diseases in few weeks. Similar histological lesions are also observed in collapsing forms of focal segmental glomerulosclerosis. The implication of several cellular stress pathways in glomerular epithlial cells during kidney disease progression has been recently suggested. Interestingly, we have identified a specific molecular signature of cellular stress (heat shock protein 27 induction) during several glomerular diseases, both in human and mouse models. HSP27 induction is mainly detected in glomerular parietal epithelial cells (PEC), whihch have recently been crucially implicated in glomerular diseases pathophysiology. Moreover, we have shown that inhibition of this pathway was associated with improvement of glomerular lesions in mouse models, and inhibition of PEC activation and migration in vitro. In the current project, by combining in vivo models of genetically modified mice, pharmacological approaches and in vitro studies of cultured glomerular PEC, we will attempt to identify the role of HSP27 in glomerular PEC after renal injury. Cellular mechanisms such as proliferation, migration or activation/dedifferentiation will be studied. In a candidate approach, we will analyze specific signalling pathways which could be involved in glomerular diseases pathophysiology and modulated by HSP27. Unbiaised global approaches using transciptomic and proteomic strategies will be also studied in HSP27- depleted PEC, according to the first results. Moreover, this signature will be studied in human available samples (blood or urine) to evaluate its potential role of non-invasive biomarker in predicting disease activity and progression. To this aim, new and highly specific tools (aptamers, exosomes extraction and characterization) will be developed and tested, according to procedures already mastered by the collaborators of the project. By identifying the exact role of HSP27 in glomerular diseases pathophysiology, this study could lead to new therapeutic strategies in human kidney diseases, since this pathway could be targeted with inhibitors already available in clinics. Besides, this work could allow us to propose new diagnostic strategies using this signature as a disease activity biomarker. Therefore, our project has the potential to develop a personalized medicine strategy in a wide range of glomerular diseases. Lastly, this study will have crucial pathophysiological implications. Given the essential role of heat shock signature during several cellular stresses (such as metabolic, hypoxic, oxidative stress), this work opens new research field in stress pathways implicated during glomerular diseases. This proposal will benefit of the complementarities between clinicians implicated in clinical research and both basic science and physiopathological model experts. By understanding the role of HSP27 in glomerular diseases, this project should have a crucial impact in strategies inhibiting glomerular disease evolution.

Chronic Kidney Disease (CKD) is a major burden of public health affecting millions of people around the world. Even though many aspects of the complex mechanisms orchestrating progression of renal disease have been identified, so far there is no specific treatment to slow down or prevent CKD progression. Therefore, identifying novel specific therapeutic targets and proposing more effective treatments against the progression of CKD is one of the major challenges of public health today. Our preliminary data showed that genetic deletion of a protein named Celen (we can't disclose the real name in the general public because is under Inserm patent deposit), exacerbated the decline of renal function in the Ang II- and nephrotoxic serum (NTS)- induced models of CKD. Inversely, activation of Celen protects against oxidative stressors (enhanced at the early stage of CKD) and prevents increase of apoptotic markers in renal cells. The specific hypothesis behind this proposal, strongly backed-up by our preliminary data, is that activation of Celen will counteract the deleterious effects of chronic renal inflammation and fibrosis, and preserve renal structure and function during kidney diseases providing a novel therapeutic target against CKD. The objectives of the present proposal are to: 1) Evaluate the role of Celen in the progression of experimental kidney disease (NTS model) using cell-specific Celen (podocyte or endothelial) gene deletion. 2) Dissect the molecular pathways implicated in the signaling of Celen in the kidney and identify novel regulators in the progression of glomerulonephritis. Specifically, we will investigate the role of Celen in mitochondrial function (i.e mPTP opening, Ca2+ overload). Using RNA-Seq and ChIP-Seq/-qPCR technologies, we will identify the full range of Celen target genes and the epigenetic enzymes mediating its nuclear signaling. 3) Examine whether cell-specific overexpression of Celen (in podocytes or endothelial cells depending on the results of 1) in adult mice is sufficient to halt or reverse the progression of glomerulonephritis. 4) Determine if pharmacological activation of Celen is nephroprotective. 5) Explore the translational relevance of its expression in biopsies. Partner's 2 lab is in charge of a cohort (CORIRLA) of CKD patients at Tenon hospital, Paris. The proposed task is to explore the cellular localization of Celen and its downstream effectors in different types of glomerulonephritis. This is a pilot study. If the results are confirmed, they will pave the way for a wider study involving more patients and partners which will be the subject of a future financial demand. We have therefore assembled two groups of internationally distinguished investigators to continue an existing collaboration and conduct basic and translational kidney research. Both partners have complementary expertise: Partner 1 is a renowned expert of the signaling, pharmacology and disease mechanisms involving Celen and Partner 2 has an international recognized expertise in renal pathophysiology and experimental models of kidney disease along with platforms for renal hemodynamics and in vivo imaging. After 3 years, we expect to deliver the following results: 1) Establish Celen as a novel actor in CKD ; 2) Obtain an in-depth analysis of Celen signaling in nephroprotection ; 3) Demonstrate that pharmacological intervention on Celen slows down or arrests progression of CKD ; 4) Observational study of Celen expression and signaling pathways in selected human nephropathies. The impact of our proposal will be scientific by identifying a new pathophysiological mechanism of CKD, socioeconomic by providing a proof of concept of a new therapy approach for CKD and cultural by giving the opportunity to young fellows to receive a high quality training thus improving their capacity for further career development in the academic or private sector.

At present, while there are innovative non-invasive biomarkers developed to diagnose acute rejection, there are no sufficiently reliable non-invasive biomarkers to assess the lesional state of the graft. Serum creatinine is not specific for renal allograft injury and does not clearly distinguish loss of function from acute rejection from another cause. In parallel, with the emergence of molecular biology technologies such as Next-Generation Sequencing (NGS), another approach using the quantification of Single Nucleotides Polymorphisms (SNPs) present on the donor's circulating DNA (dd-cfDNA) has been studied. . Data from several studies suggest that dd-cfDNA levels in blood and urine can detect rejection in heart, lung, liver and kidney allografts. However, it is currently not possible to identify the cellular origin of graft damage with these technologies. To make a diagnosis on the type of rejection, the use of solid biopsy is mandatory. The Banff classification established by different consortia is used as a reference method to characterize and diagnose the typology of renal transplant rejection.

Heart transplantation is the gold standard treatment for advanced heart failure, a major cause of premature death. The critical organ shortage however limits this therapeutic approach with a ratio of two recipient candidates for one allograft nowadays. The allocation of a growing number of marginal grafts increases the risk of primary graft failure and early death after transplant. All the most, conventional static cold storage allows for only 4 hours of ischemia. This time limitation induces a geographic restriction between donor and recipient. Ex vivo heart perfusion (EVHP) has been applied to expand the duration of organ preservation. This method provides continuous perfusion of the donor heart using oxygenated blood at 34°C. However no clearance of deleterious molecules for the heart (e.g. pro-inflammatory cytokines, oxygen radicals) is provided by commercially available machines for EVHP. Prolonged EVHP is therefore limited to a maximum duration of 10 hours. There is therefore a need for a portable blood filter connected to EVHP platform. Since there is no commercially available approach to achieve our clinical need, we aim at developing an optimal blood filtration device to ensure the homeostasis of the perfusate during prolonged EVHP. Our study aims to apply microfluidic technology for blood filtration during EVHP. We trust this approach would rapidly increase the chance for heart transplantation: 1) By increasing the duration for organ preservation, we could remove geographic restrictions for organ allocation; 2) By applying cardiovascular imaging using contrast agents, we could diagnose coronary artery disease in cardiac allografts from high-risk donors (age>55 years, cardiovascular risk factors); 3) By improving the quality of organ preservation, we could apply pharmacological intervention for organ repair and rehabilitation of marginal grafts before transplantation.