Rescuing compounds for Lesch-Nyhan disease identified using stem cell–based phenotypic screening

Valentin Ruillier,Michel Cailleret,Gurvan Mahé,Claire Boissart,Johana Tournois,Marc Peschanski,Laure Chatrousse,Alexandra Benchoua,Marie Lasbareilles

doi:10.1172/jci.insight.132094

Abstract

Lesch-Nyhan disease (LND) is a rare monogenic disease caused by deficiency of the salvage pathway enzyme hypoxanthine-guanine phosphoribosyltransferase (HGPRT). LND is characterized by severe neuropsychiatric symptoms that currently cannot be treated. Predictive in vivo models are lacking for screening and evaluating candidate drugs because LND-associated neurological symptoms are not recapitulated in HGPRT-deficient animals. Here, we used human neural stem cells and neurons derived from induced pluripotent stem cells (iPSCs) of children affected with LND to identify neural phenotypes of interest associated with HGPRT deficiency to develop a target-agnostic-based drug screening system. We screened more than 3000 molecules and identified 6 pharmacological compounds, all possessing an adenosine moiety, that corrected HGPRT deficiency-associated neuronal phenotypes by promoting metabolism compensations in an HGPRT-independent manner. This included S-adenosylmethionine, a compound that had already been used as a compassionate approach to ease the neuropsychiatric symptoms in LND. Interestingly, these compounds compensate abnormal metabolism in a manner complementary to the gold standard allopurinol and can be provided to patients with LND via simple food supplementation. This experimental paradigm can be easily adapted to other metabolic disorders affecting normal brain development and functioning in the absence of a relevant animal model.

Highlights

Purines are both essential molecules for nucleic acid assembly and the most common carriers of chemical energy in mammalian cells
To develop a relevant model of Lesch-Nyhan disease (LND) amenable to drug screening, we used induced pluripotent stem cells (iPSCs) reprogrammed from fibroblasts derived from children with LND to obtain hypoxanthine-guanine phosphoribosyltransferase (HGPRT)-deficient neural stem cells (NSC) and neurons as a starting material
This indicated that HGPRT loss-of-function mutations did not compromise fibroblast reprogramming or iPSC commitment to the neural lineage when phenocopying the enzymatic defect associated with LND

Summary

Introduction

Purines are both essential molecules for nucleic acid assembly and the most common carriers of chemical energy in mammalian cells. The cellular pool of purines is tightly maintained by the balance among their de novo synthesis, recycling, and degradation [1]. Mutations in enzymes of the synthesis or recycling pathways are accompanied by devastating neurological symptoms [2]. One of the most described purine-associated pediatric disorders is Lesch-Nyhan disease (LND), which is caused by deficiency of the salvage pathway enzyme hypoxanthine-guanine phosphoribosyltransferase (HGPRT), an X chromosome–encoded protein [3, 4]. The recycling of guanine and hypoxanthine into GMP and inosine monophosphate (IMP) is inefficient, leading to uric acid accumulation, formation of uric acid–containing kidney stones, and renal failure. Hyperuricemia and the formation of kidney stones can be controlled by the xanthine oxidase inhibitor 1,2-dihydro-4H-pyrazolo, pyrimidin-4-one Hyperuricemia and the formation of kidney stones can be controlled by the xanthine oxidase inhibitor 1,2-dihydro-4H-pyrazolo, pyrimidin-4-one (allopurinol, ref. 7)

Methods

Results

Conclusion