Cyclophilin D promotes tubular cell damage and the development of interstitial fibrosis in the obstructed kidney
CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY
Authors: Hou, Weiping; Leong, Khai G.; Ozols, Elyce; Tesch, Greg H.; Nikolic-Paterson, David J.; Ma, Frank Y.
Abstract
Cyclophilin D (CypD) is an important component in mitochondrial-dependent tubular cell death in acute kidney injury. However, it is not known whether CypD contributes to tubular cell damage in chronic interstitial fibrosis. We investigated this question in the unilateral ureter obstruction (UUO) model of renal interstitial fibrosis. Groups of CypD(-/-) and wild type (WT) mice were killed 7 or 12days after UUO surgery. The significant tubular cell apoptosis seen in WT UUO was significantly reduced in CypD(-/-) UUO based on TUNEL and cleaved caspase 3 staining. Other markers of tubular cell damage; loss of E-cadherin and AQP1 expression, were also reduced in the CypD(-/-) UUO kidney. This reduced tubular damage was associated with less inflammation and a partial protection against loss of peritubular capillaries. The prominent accumulation of -SMA+ myofibroblasts and interstitial collagen deposition seen in WT UUO was significantly reduced in CypD(-/-) UUO on day 12, but not day 7. Activation of several pro-fibrotic signalling pathways (p38 MAPK, JNK and Smad3) was unaltered in CypD(-/-) UUO, arguing that CypD acts independently to promote renal fibrosis. CypD deletion in cultured tubular cells attenuated oxidative stress-induced pro-inflammatory, pro-fibrotic and apoptotic responses; however, responses to angiotensin II and LPS were unaffected. In contrast, CypD deletion in cultured renal fibroblasts did not affect PDGF-induced proliferation or TGF-1-induced collagen I expression, suggesting no direct role of CypD in the fibroblast response. In conclusion, we have identified a role for CypD in chronic tubular cell damage and in the development of renal interstitial fibrosis.
Inhibitory effects of lentivirus mediated RNA interference targeting human AQP1 gene on the proliferation of human colon carcinoma SW480 cells and the expression of VEGF
INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL MEDICINE
Authors: Kong, Bin; Zhao, Shi-Peng
Abstract
Purpose: The objective of the present study was to construct the lentiviral expression vector for RNA interference (RNAi) of human AQPl gene in colon carcinoma SW480 cells, which may provide research foundation for investigating the mechanisms that AQP1 gene functions for the proliferation of human colon carcinoma SW480 cells and the expression of VEGF in the cells. Methods: Four effective sequences of RNAi targeting human AQPl gene were confirmed. Both sense and antisense Oligo DNA of the targeting sequences were designed, synthesized and cloned into the lentiviral vector pEGFP-N1-3FLAG. After transfected with lentiviral vector of T293 cells, and the titer of the lentivirus was tested. SW480 cells were infected with the lentivirus and the expression of AQPl mRNA and protein in SW480 cells was detected by real-time quantitative polymerase chain reaction (RT-PCR) and Western blotting. The propagation of SW480 cells was detected by MTT and expression of VEGF in SW480 cells was detected by RT-PCR. Results: A recombinant lentiviral vector expressing shRNA against AQP1 gene was obtained confirmed by DNA sequencing. The titre of virus was 2x10(9) TU/ml. AQP1 mRNA and protein expression in SW480 cells after infected with lentiviral vector was decreased remarkably. The mRNA expression was 60%, respectively, compared with the control group. And the lentiviral shRNA expression vector reduced cell pro1 if eration 5 d after stable AQP1 gene knock-down in SW480 cells. Meanwhile, the expression of VEGF mRNA was inhibited. Discussion: The lentiviral shRNA expression vector targeting human AQP1 gene capable of stable AQP1 gene knock-down SW480 cells has been successfully constructed, which provides a basis for further study of mechanisms that AQP1 gene acts for proliferation of colon carcinoma. And preliminary conclution was drawn that AQP1 gene may promote the growth of SW480 cells and the expression of VEGF.