Journal: Journal of the American Society of Nephrology
Article Title: Loss of Klotho Contributes to Kidney Injury by Derepression of Wnt/β-Catenin Signaling
doi: 10.1681/asn.2012080865
Figure Lengend Snippet: Figure 5. TGF-b1 represses Klotho expression and Klotho inhibits the TGF-b1–mediated induction of various fibrogenic genes in vitro. (A–D) Western blot analyses show that TGF-b1 inhibited Klotho expression in a dose- and time-dependent manner. HKC-8 cells were incubated with different doses of TGF-b1 for 24 hours (A and B) or the same concentration of TGF-b1 (2 ng/ml) for various periods of time (C and D) as indicated. Representative Western blots (A and C) and quantitative data (B and D) are presented. *P,0.05 versus controls (n=3). (E) RT-PCR shows that TGF-b1 repressed Klotho mRNA expression in tubular epithelial cells. HKC-8 cells were treated with TGF-b1 (2 ng/ml) for various periods of time as indicated. Expression of Klotho, TNF-a, and b-actin mRNA was analyzed. (F and G) Repression of Klotho by TGF-b1 depends on Smad3 signaling. HKC-8 cells were pretreated with TGF-b type I receptor inhibitor (SB431542; 10 mM) or Smad3 inhibitor (SIS3; 10 mM) for 1 hour, followed by incubation with TGF-b1. Representative Western blot (F) and quantitative data (G) are presented. *P,0.05 versus controls (n=3); †P,0.05 versus TGF-b1 alone (n=3). SB, SB431542. (H) TGF-b1 does not induce Wnt expression in tubular epithelial cells. HKC-8 cells were treated with TGF-b1 (2 ng/ml) for various periods of time as indicated. Expression of various Wnt mRNA was assessed by RT-PCR. (I–L) Western blot analyses and quantitative data show that Klotho inhibited b-catenin activation and its target gene expression induced by TGF-b1. HKC-8 cells were transfected with empty vector (pcDNA3) or Klotho expression vector (pV5-mKlotho) as indicated, followed by incubation with TGF-b1 (2 ng/ml). Western blot (I) and quantitative data for active b-catenin (J), PAI-1 (K), and Snail1 (L) are presented. (M and N) Klotho abolished TGF-b1–mediated fibrogenic actions. HKC-8 cells were transfected with empty vector (pcDNA3) or Klotho expression vector (pV5-mKlotho) as indicated, followed by incubation with TGF-b1 (2 ng/ml). Total cell lysates were immunoblotted with specific antibodies against fibronectin, a-SMA and actin, respectively. *P,0.05 versus pcDNA3 controls; †P,0.05 versus TGF-b1 alone (n=3).
Article Snippet: HKC-8 cells were transiently transfected with various expression vectors, such as HA- tagged Wnt1 expression plasmid (pHA-Wnt1; Upstate Biotechnol- ogy, Lake Placid, NY), human membrane Klotho (pV5-mKlotho; Addgene) or secreted Klotho (pV5-sKLotho) by using Lipofectamine 2000 reagent (Invitrogen, Grand Island, NY).
Techniques: Expressing, In Vitro, Western Blot, Incubation, Concentration Assay, Reverse Transcription Polymerase Chain Reaction, Activation Assay, Targeted Gene Expression, Transfection, Plasmid Preparation