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Hureaux, M.

Publications and source records attributed to Hureaux, M..

2 recordsLinked to original sources

Evaluation of Prostaglandin Receptor Agonists and Eupatilin in the Context of Nephronophthisis

BackgroundPrimary cilia are sensory antennas that are present on the majority of quiescent vertebrate cells where they mediate key signaling during development and in response to environmental stimuli. Defects in primary cilia result in a group of heterogeneous inherited disorders with overlapping phenotypes, called ciliopathies. Nephronophthisis is an autosomal recessive tubulo-interstitial kidney ciliopathy with more than 25 identified genes called NPHP. Presently, no treatment exists beyond supportive care and kidney transplant, underscoring the need for novel therapies. MethodsUsing a phenotypic screening approach in cultured cell lines, we previously identified prostaglandin analogues as candidate therapeutic molecules based on their ability to rescue ciliogenesis defects in kidney tubular cells from NPHP1 patients. Here, we have investigated the potential beneficial effects of ROCK inhibitors and Eupatilin, similarly identified by other groups in different NPHP contexts, in kidney cells from NPHP1 and IQCB1/NPHP5 patients as well as in a zebrafish NPHP mutant line (traf3ip1/ift54). ResultsEupatilin partially rescued NPHP1-associated ciliogenesis defects. Transcriptomic analyses pointed out that cell cycle progression was inhibited by Eupatilin, likely explaining its broad effects on cilia assembly. Interestingly, while ciliary defects also observed in NPHP5 patient cells were rescued by both prostaglandins and Eupatilin, only prostaglandin analogues were able to reduce pronephric cysts size in the used nphp zebrafish model. ConclusionOur study indicates that these molecules can show beneficial effects across genetic contexts and shed light on their potential as therapeutic interventions for nephronophthisis.

cell biology↗

SLC4A1 MUTATIONS THAT CAUSE DISTAL RENAL TUBULAR ACIDOSIS ALTER CYTOPLASMIC PH AND CELLULAR AUTOPHAGY

Distal renal tubular acidosis (dRTA) is a disorder characterized by the inability of the collecting duct system to secrete acids during metabolic acidosis. The pathophysiology of dominant or recessive SLC4A1 variant related dRTA has been linked with the mis trafficking defect of mutant kAE1 protein. However, in vivo studies in kAE1 R607H dRTA mice and humans have revealed a complex pathophysiology implicating a loss of kAE1-expressing intercalated cells and intracellular relocation of the H+-ATPase in the remaining type-A intercalated cells. These cells also displayed accumulation of ubiquitin and p62 autophagy markers. The highly active transport properties of collecting duct cells require the maintenance of cellular energy and homeostasis, a process dependent on intracellular pH. Therefore, we hypothesized that the expression of dRTA variants affect intracellular pH and autophagy pathways. In this study, we report the characterization of newly identified dRTA variants and provide evidence of abnormal autophagy and degradative pathways in mouse inner medullary collecting duct cells and kidneys from mice expressing kAE1 R607H dRTA mutant protein. We show that reduced transport activity of the kAE1 variants correlated with increased cytosolic pH, reduced ATP synthesis, attenuated downstream autophagic pathways pertaining to the fusion of autophagosomes and lysosomes and/or lysosomal degradative activity. Our study elucidated a close relationship between the expression of defective kAE1 proteins, reduced mitochondrial activity and decreased autophagy and protein degradative flux.

physiology↗