Kidney Week

Abstract: FR-PO1032

TRPC6 Overexpression Mice Produced Proteinuria with Downregulated Podocyte Genes

Session Information

• Genetic Diseases of the Kidneys: Non-Cystic - II
  October 26, 2018 | Location: Exhibit Hall, San Diego Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Genetic Diseases of the Kidney

• 1002 Genetic Diseases of the Kidney: Non-Cystic

Authors

• Sun, Zi Jin, National University of Singapore , Singapore, Singapore

Zi Jin Sun,

• Zhang, Yaochun, National University of Singapore , Singapore, Singapore

Yaochun Zhang,

• Ng, Jun li, National University of Singapore , Singapore, Singapore

Jun li Ng,

• Liao, Ping, National Neuroscience Institute, Singapore, Singapore

Ping Liao,

• Soong, Tuck wah, National University of Singapore , Singapore, Singapore

Tuck wah Soong,

• Chong, Siong-Chuan, National University of Singapore , Singapore, Singapore

Siong-Chuan Chong,

• Chan, Yiong Huak, National University of Singapore , Singapore, Singapore

Yiong Huak Chan,

• Yap, Hui Kim, National University Hospital, Singapore, Singapore

Hui Kim Yap,

• Ng, Kar Hui, National University of Singapore , Singapore, Singapore

Kar Hui Ng,

Background

Mutations in transient receptor potential channel-6 (TRPC6) can cause autosomal dominant FSGS. We have previously identified novel p.R68W TRPC6 gain-of-function mutation. We aim to study the disease-causing mechanism of p.R68W mutation.

Methods

Wild type (OE^wt) and p.R68W (OE^mut) TRPC6 were overexpressed in FVB/N mice by pronuclear microinjection. The albumin:creatinine ratios were obtained. Podocyte gene expressions were measured by reverse-transcription PCR and western blot analysis. Podocyte ultrastructural changes were assesssed by transmission electron microscopy and transgene localization was performed by immunogold staining. Statistical analysis was performed using Mann-Whitney U test.

Results

Over one third of both groups of overexpression mice had albuminuria, and lower body weights compared with control mice from 6 month. Interestingly, OE^wt were significantly lighter compared with OE^mut since 6.5 month. Kidney electron microscopy slices demonstrated extensive podocyte foot process effacement in both OE mice. Immunogold staining revealed TRPC6 in OE^wt mice localized predominantly in the central cytoplasmic areas, whereas in OE^mut, TRPC6 occurred predominantly at the peripheral and central parts of the foot processes. Quantitative PCR data showed that nephrin and podocin expressions were decreased in OE mice compared to wild-type, and to a greater degree in the OE^wt compared to OE^mut.

Conclusion

Our work suggests p.R68W mutation may affect TRPC6 intracellular trafficking and its interactions with the slit diaphragm proteins in the podocytes.

Funding

• Government Support - Non-U.S.