Agonists of prostaglandin E ₂ receptors as potential first in class treatment for nephronophthisis and related ciliopathies

Significance

Juvenile nephronophthisis (NPH) is a renal ciliopathy due to a dysfunction of primary cilia for which no curative treatment is available. This paper describes the identification of agonists of prostaglandin E ₂ receptors as a potential therapeutic approach for the most common NPHP1-associated ciliopathies. We demonstrated that prostaglandin E ₁ rescues defective ciliogenesis and ciliary composition in NPHP1 patient urine-derived renal tubular cells and improves ciliary and kidney phenotypes in our NPH zebrafish and Nphp1 ^−/− mouse models. In addition, Taprenepag alleviates the severe retinopathy observed in Nphp1 ^−/− mice. Finally, transcriptomic analyses pointed out several pathways downstream the prostaglandin receptors as cell cycle progression, extracellular matrix, or actin cytoskeleton organization. Altogether, our findings provide an alternative for treatment of NPH.

Abstract

Nephronophthisis (NPH) is an autosomal recessive tubulointerstitial nephropathy belonging to the ciliopathy disorders and known as the most common cause of hereditary end-stage renal disease in children. Yet, no curative treatment is available. The major gene, NPHP1, encodes a protein playing key functions at the primary cilium and cellular junctions. Using a medium-throughput drug-screen in NPHP1 knockdown cells, we identified 51 Food and Drug Administration-approved compounds by their ability to alleviate the cellular phenotypes associated with the loss of NPHP1; 11 compounds were further selected for their physicochemical properties. Among those compounds, prostaglandin E ₁ (PGE1) rescued ciliogenesis defects in immortalized patient NPHP1 urine-derived renal tubular cells, and improved ciliary and kidney phenotypes in our NPH zebrafish and Nphp1 knockout mouse models. Furthermore, Taprenepag, a nonprostanoid prostaglandin E ₂ receptor agonist, alleviated the severe retinopathy observed in Nphp1 ^−/− mice. Finally, comparative transcriptomics allowed identification of key signaling pathways downstream PGE1, including cell cycle progression, extracellular matrix, adhesion, or actin cytoskeleton organization. In conclusion, using in vitro and in vivo models, we showed that prostaglandin E ₂ receptor agonists can ameliorate several of the pleotropic phenotypes caused by the absence of NPHP1; this opens their potential as a first therapeutic option for juvenile NPH-associated ciliopathies.