ESPN 53rd Annual Meeting

ESPN 2021


 
Renal and extra renal manifestations in adult zebrafish model of cystinosis
SANTE PRINCIERO BERLINGERIO 1 JUNLING HE 2 LIES DE GROEF 1 PIETER BAATSEN 3 SARA CAIROLI 4 BIANCA MARIA GOFFREDO 4 FRANCESCO EMMA 4 LIEVE MOONS 1 BERT VAN DEN HEUVEL 1 HANS BAELDE 2 ELENA LEVTCHENKO 1

1- KU LEUVEN
2- LUMC
3- VIB-KULEUVEN
4- BAMBINO GESù CHILDREN’S HOSPITAL
 
Introduction:

Cystinosis is a rare, incurable autosomal recessive disease caused by mutations in the CTNS gene, which encodes for the cystine transporter cystinosin leading to lysosomal cystine accumulation in all cells, with kidneys being the first affected organs. Treatment with cysteamine decreases the cystine accumulation, but does not reverse the renal Fanconi syndrome, glomerular injury or loss of renal function. We have developed a zebrafish larvae model having truncating mutation in ctns, which recapitulates kidney phenotype of cystinosis. In this study, we characterized the adult cystinosis zebrafish model to evaluate the long term effects of cystinosis on kidney and extra renal organs.

Material and methods:

Cystinosis (ctns-/-) zebrafish of 18 months and control (WT) zebrafish were studied. Histological studies of kidneys and extra-renal organs were performed. Cleaved caspase-3 staining was used to evaluate apoptosis in the kidney. Cystine accumulation was evaluated via liquid chromatography-mass spectrometry and toluidine blue staining. For the fertility studies, the number of total eggs and fertile eggs produced by breeding female and male ctns- /- zebrafish compared to WT zebrafish was evaluated.

Results:

ctns-/- zebrafish show cystine accumulation, glomerular hypertrophy and proximal tubular accumulation of hyaline-like eosinophilic droplets and vacuolated cytoplasm. Moreover, the cystinotic zebrafish show increased apoptosis in proximal tubules. In addition, instead of the typical striped pattern, ctns-/- zebrafish presents an altered melanin skin pigmentation resulting in spotted skin. Lastly, male ctns-/- zebrafish presents spermatogenic cysts enriched in spermatozoa in the testis, while female presented increased percentage of unfertilized eggs.

Conclusions:

The ctns-/- zebrafish model reproduces several human phenotypes of cystinosis such as cystine accumulation, altered kidney morphology, impaired skin pigmentation and decreased fertility. This model may be useful for studying long-term effects of cystinosis and for testing novel drugs for correcting cystinosis phenotype.