Fig. 4.

JNK inhibitor represses L5 effect on STRA6 cascades and renal injury. A: Western blots show STRA6, CRBP1, RARα, RARγ, RXRα, pSmad2, and collagen 1 (Col1) of Ctl, L1-, or L5-treated RETCs with or without SP600125 treatment for 24 h (n = 3). Quantitative analysis showed that L5 treatment decreased STRA6 (B), CRBP1 (C), RARα (D), RARγ (E), and RXRα (F), but increased the pSmad2/Smad2 ratio (G) and collagen 1 (H). All of these effects of L5 were reversed in SP600125-treated RETCs under L5-stimulation. I: Representative optical microscopy images show nuclei of apoptotic cells (thick dark stain) in Ctl, L1-treated, and L5-treated cells with or without SP600125 treatment. SP600125 decreased the nuclei of apoptotic cells in RETCs under L5-stimulation. J: ELISA showed that SP600125 treatment attenuated the increase of TGFβ₁ concentration in the culture medium of L5-treated RETCs. K: Real-time PCR analysis revealed that SP600125 significantly recovered the decreased mRNA levels of STRA6, CRBP1, RARα, and RXRα in L5-treated RETCs. All results are represented as mean ± SE. *P < 0.05, **P < 0.01 versus Ctl and L1; ^#P < 0.05, ^##P < 0.05 versus L5.