Abstract: FR-PO673

Beneficial Effects of Proteasome Inhibitors (PIs) Administered after Onset of Proteinuria in a Model of Minimal Change Disease (MCD)

Session Information

Category: Glomerular

  • 1001 Glomerular: Basic/Experimental Immunology and Inflammation

Authors

  • Vashistha, Himanshu, Ochsner Health System, New Orleans, Louisiana, United States
  • Bradley, Allyson E., Ochsner Health System, New Orleans, Louisiana, United States
  • Abbruscato, Frank C, Ochsner Health System, New Orleans, Louisiana, United States
  • Walker, Patrick D., Arkana Laboratories, Little Rock, Arkansas, United States
  • Shah, Sudhir V., University of Arkansas, Little Rock, Arkansas, United States
  • Baliga, Radhakrishna, Ochsner Health System, New Orleans, Louisiana, United States
Background

Proteasomes play a major role in the pathophysiology of several disease processes in part through its action on a crucial transcription factor, nuclear factor-kappa B (NF-κB). NF-κB regulates the expression of a variety of inflammatory genes including cytochrome P450 (CYP) which plays a major role in MCD. We have shown previously that administration of PIs prior to the onset of proteinuria resulted in marked protection against puromycin aminonucleoside (PAN) -induced proteinuria. However, the role of PIs in ongoing glomerular injury and their potential beneficial effects following the establishment of significant proteinuria have not been previously examined.
The current study was designed to determine the effect of PIs administration following the onset of proteinuria in a model of MCD and to study the potential mechanism involved utilizing in vitro cultured human podocytes (HP)

Methods

MCD was induced in SD rats by injecting a single dose of PAN intra-venously (IV). Proteinuria was measured as albumin to creatinine ratio (ACR) (µg/mg) until day 10. MG-132 was administered by osmotic pumps and Carfilzomib (CAR) was administered IV following onset of proteinuria. Proteins were analyzed by western blot and immunocytochemistry. Immunohistochemical analysis was also performed on the kidney cortical sections.

Results

Administration of MG-132 and CAR after the onset of PAN induced proteinuria (PAN 75±14, PAN+MG132 84±6, PAN+CAR 52±7; NS differences between groups; values are mean ±se) prevented the further increase until sacrifice (PAN 147±13, PAN+MG132 104±17*, PAN+CAR 98+13*; P<0.05* compared to PAN alone). This was accompanied by marked decrease in lipid peroxidation in PIs treated rats. MG-132 significantly decreased the nuclear translocation of NF-KB, activation of IL-6, up regulation of CYP, marked reduction in H2O2 release and 8-Oxo-dG expression in cultured HPs. MG-132 and CAR blunted the nuclear translocation of Nrf-2, preserved Keap-1 expression, upregulated PAN induced HO-1 and SOD with significant decrease in apoptosis.

Conclusion

These in vitro and in vivo data imply the crucial role of proteasome in progressive glomerular injury. CAR, which is currently used in humans should be considered as a potential therapeutic alternative in MCD.

Funding

  • Private Foundation Support