Abstract: TH-PO1066

Establishing a Drosophila Model System to Study the Molecular Function of Human Genes Identified from Patients with Nephrolithiasis/Nephrocalcinosis

Session Information

Category: Mineral Disease

  • 1204 Mineral Disease: Nephrolithiasis

Authors

  • Zhang, Fujian, Nanfang Hospital, Southern Medical University, Guangzhou, China
  • Fan, Qiuxia, Nanfang Hospital, Southern Medical University, Guangzhou, China
  • Hong, Xizhen, Nanfang Hospital, Southern Medical University, Guangzhou, China
  • Feng, Xiaoming, Nanfang Hospital, Southern Medical University, Guangzhou, China
  • Hou, Fan Fan, Nanfang Hospital, Southern Medical University, Guangzhou, China
Background

Nephrolithiasis/nephrocalcinosis is a frequent condition that affects 15% of adults, causing a huge burden on health care systems globally. Calcium oxalate stones account for more than 75% of renal stone diseases. In recent years, more than 30 genes have been identified as novel monogenic causes of kidney stone disease by using whole exome sequencing. However, the pathological function of the majority of these novel genes have not been validated in vivo.

Methods

First, we established the principal cell-specific gene knock-down method using UAS-RNAi/Gal4 system and examined its effect on calcium oxalate stone formation. Then, we investigated the effect of fly homology of 30 human genes identified from patients with kidney stone disease on calcium oxalate stone formation. We also examined the effect of calcium oxalate stone formation on lifespan. Furthermore, we examined the effect of these genes on the metabolism of oxalate in malphigian tubule cells.

Results

In this study, we found that knockdown of genes encoding v-ATPase protein complex in malphigian tubule principal cells led to the formation of large calcium oxalate stones. We also found that defects in 80% (24 of 30) fly homology of 30 known nephrocalcinosis/nephrolithiasis genes led to the accumulation of calcium oxalate stone in malphigian tubule. We also observed that the formation of large kidney stones significantly shortened the lifespan in adult flies. Furthermore, we found that RNAi knockdown of these nephrolithiasis genes led to the accumulation of oxalate in malphigian tubules, suggesting that these nephrolithiasis genes in principal cells may affect the secrection of oxalate from malphigian tubule.

Conclusion

In this study, we present the first Drosophila model system to study the molecular function of human genes identified from patients with nephrolithiasis/nephrocalcinosis. These results suggest that Drosophila malphigian tubules could be a very powerful system to screen genes involved in the formation of calcium oxalate stone in vivo, and small molecules that could be used to dissolve calcium oxalate stones in patients with nephrolithiasis/nephrocalcinosis.

Funding

  • Government Support - Non-U.S.