Kidney Week

Abstract: TH-OR044

Loss of Cep120 Disrupts Centriole Maturation and Ciliary Assembly and Function and Causes Cystic Kidney Disease

Session Information

• Cystic Kidney Diseases: Genes, Mechanisms, Interventions
  November 02, 2017 | Location: Room 390, Morial Convention Center
  Abstract Time: 05:06 PM - 05:18 PM

Category: Genetic Diseases of the Kidney

• 801 Cystic Kidney Diseases

Authors

• Betleja, Ewelina, Washington University, St Louis, Missouri, United States

Ewelina Betleja,

• Cheng, Tao, Washington University, St Louis, Missouri, United States

Tao Cheng,

• Mahjoub, Moe, Washington University, St Louis, Missouri, United States

Moe Mahjoub, PhD



http://mahjoublab.dom.wustl.edu/Home.html

Background

Jeune asphyxiating thoracic dystrophy (JATD) is a skeletal dysplasia characterized by a small thoracic cage, shortened bones in the limbs, and polydactyly. Infants develop difficulties with breathing due to abnormal development of their thoracic cage, but may survive into early childhood following surgery to correct these defects. However, these children develop life-threatening renal abnormalities, namely cystic kidneys. Whole-exome sequencing of JATD patients recently identified mutations in CEP120, which we previously showed to be important for centriole duplication. What remains unknown is the functional in vivo role of Cep120 during embryonic kidney development and adult kidney homeostasis.

Methods

Two complementary approaches were used to characterize the loss-of-function of Cep120. First, siRNA-mediated depletion of Cep120 was performed in mouse embryonic fibroblasts and epithelia to analyze its role in vitro. Next, we utilized a transgenic mouse model harboring a conditional allele (Cep120^f/f) to delete Cep120 in the developing kidney. Cep120^f/f mice were crossed with Six2-Cre animals to delete the gene in the metanephric mesenchyme, and with Hoxb7-Cre animals to knock out Cep120 in the ureteric bud epithelium.

Results

Here we show that Cep120 plays a critical inhibitory role at the daughter centriole. Depletion of Cep120 in quiescent cells causes accumulation of pericentriolar material (PCM) components at the daughter centriole including pericentrin, Cdk5Rap2, ninein and Cep170. The elevated PCM levels result in an overall increase in microtubule-nucleating capacity at the centrosome. Consequently, loss of Cep120 leads to aberrant dynein-dependent trafficking of centrosomal proteins, dispersal of centriolar satellites, and defective ciliary assembly and function. Finally, we show that deletion of Cep120 in the developing mouse kidney recapitulates the in vitro cellular phenotypes, and results in rapid renal cystogenesis that is evident at birth.

Conclusion

Our results indicate that Cep120 inhibits untimely maturation of the daughter centriole, and defines a novel mechanism that regulates the asymmetric properties of the two centrioles in quiescent cells. These data provide the first detailed characterization of the role of Cep120 (and potentially other daughter centriolar proteins) in renal cystogenesis of patients with JATD.

Funding

• NIDDK Support