Receptor Activator of NF-kappaB and Podocytes: Towards a Function of a Novel Receptor-Ligand Pair in the Survival Response of Podocyte Injury
Figure 1
Identification of RANK and RANKL as Upregulation Genes in the Rat Podocyte Injury Model.
(A) RANK protein expression was determined by using Western blot analysis with a RANK antibody. GAPDH immunoblotting served as a loading control and confirmed equal protein loading between samples. RANK protein was in low abundance in the rat control. By contrast, RANK increased in PAN models (5.8±0.7-fold of controls, n = 6, p<0.01). (B) The levels of RANKL protein increased in PAN rat kidney as compared with control. (C) Induction of RANK was revealed in podocytes in the PAN model using immunofluorescence. RANK expression (red) was low in control glomeruli from rat and colocalized with the podocyte marker synaptopodin (green). In podocytes from animals with PAN, RANK expression was substantially upregulated in podocytes, resulted in a yellow overlap with synaptopodin (Merge). (D) Immunogold analysis of RANK in glomerular walls of normal and PAN rats. RANK was substantially induced in the top of the foot process membrane and the cytoplasm of podocytes in PAN rats. Black arrows mark RANK in podocytes. (E) Induction of RANKL mRNA was upregulated in PAN rats kidney. Quantitative real-time RT-PCR was performed on kidney from PAN rats (2.6±0.4-fold of controls, n = 6). *Compared with control, p<0.01.