Abstract: SA-PO224

TRPC5 Overexpression and Activation Do Not Per Se Cause Nor Augment Kidney Disease

Session Information

  • Glomerular: Cell Biology
    November 04, 2017 | Location: Hall H, Morial Convention Center
    Abstract Time: 10:00 AM - 10:00 AM

Category: Glomerular

  • 1003 Glomerular: Cell Biology

Authors

  • Wang, Xuexiang, Rush University Medical Center, Chicago, Illinois, United States
  • Dande, Ranadheer, Rush University Medical Center, Chicago, Illinois, United States
  • Yu, Hao, Rush University Medical Center, Chicago, Illinois, United States
  • Altintas, Mehmet M., Rush University Medical Center, Chicago, Illinois, United States
  • Reiser, Jochen, Rush University Medical Center, Chicago, Illinois, United States
Background

The transient receptor potential canonical cation channel, subfamily C, member 5 (TRPC5) is broadly expressed in brain and kidney with the capability to mediate the calcium (Ca2+) influx as well as cell migration. It was reported that TRPC5 is vital for Ca2+ homeostasis in podocytes due to its location in podocyte foot processes. It is believed to regulate podocyte cytoskeletal remodeling through its association with active Rac1 GTPase. Genetic knockout or pharmacological inhibition of TRPC5 protects mice from albuminuria. However, the gain in function role of TRPC5 in vivo has not been explored.

Methods

Two novel transgenic mouse models (C57BL/6, B/6) were developed by overexpressing either wild-type TRPC5 (TG) or the dominant negative TRPC5 (DN, pore mutant), respectively. Highly expressed TRPC5 was validated by mRNA expression, Western blot and glomerular immunofluorescence (IF). The natural progression of proteinuria was quantified over time and histology was examined by the end at 8 months old mice. LPS-induced albuminuria was measured at 24 and 48 hours after two experiments with separate injection regimens and TEM of podocytes was analyzed. Treatment with TRPC5 agonist Englerin A and antagonist ML204 were performed and proteinuria was compared.

Results

TRPC5 mRNA and protein level were significantly higher in TG and DN compared with B/6. Glomerular IF exhibited stronger TRPC5 staining in two transgenic mice than B/6 mice. Neither TG nor DN developed increased proteinuria at 8 months old. Histology analysis showed no noticeable abnormalities at this age. Both single high dose LPS challenge and two lower doses LPS challenge demonstrated substantially augmented proteinuria. However, no difference in proteinuria was found among TG, DN and B/6. TEM analysis revealed a similar level of foot process effacement among three groups of animals. TRPC5 activator Englerin A injection induced no change in proteinuria. TRPC5 inhibitor ML204 treatment did not rescue kidney filtration barrier injury from LPS challenge.

Conclusion

Overexpression of TRPC5 does not cause kidney injury over time per se or more podocyte damage to LPS challenge. Neither agonizing nor antagonizing TRPC5 by drug affects the podocytes function and proteinuria level. TRPC5 appears not as a mediator of glomerular kidney disease. Its role in other renal diseases requires further study.

Funding

  • NIDDK Support