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Kidney Week

Abstract: FR-PO955

Connective Tissue Growth Factor Is Regulated by TGF-β2 and ERK via Smad2/3 in Autosomal Dominant Polycystic Kidney Disease

Session Information

Category: Genetic Diseases of the Kidney

  • 1001 Genetic Diseases of the Kidney: Cystic

Authors

  • Kim, Hyunho, Seoul National University Hospital, JongNo-Gu, SEOUL, Korea (the Republic of)
  • Kim, Ji-Hye, Seoul National University Hospital, JongNo-Gu, SEOUL, Korea (the Republic of)
  • Sung, Jinmo, Seoul National University Hospital, JongNo-Gu, SEOUL, Korea (the Republic of)
  • Kim, Hyunsuk, Chuncheon Sacred Heart Hospital, Chuncheon, GangWon-Do, Korea (the Republic of)
  • So, Jeong ok, Seoul National University Hospital, JongNo-Gu, SEOUL, Korea (the Republic of)
  • Kim, Jiseon, Seoul National University Hospital, JongNo-Gu, SEOUL, Korea (the Republic of)
  • Ryu, Hyunjin, Seoul National University Hospital, JongNo-Gu, SEOUL, Korea (the Republic of)
  • Park, Hayne C., Kangnam Sacred Heart Hospital, SEOUL, Korea (the Republic of)
  • Oh, Yun Kyu, Department of Internal Medicine, Boramae Medical Center, Seoul, Korea (the Republic of)
  • Ahn, Curie, Seoul National University Hospital, JongNo-Gu, SEOUL, Korea (the Republic of)
Background

In autosomal dominant polycystic kidney disease (ADPKD), the mechanism of pericystic fibrosis is not elucidated. Connective tissue growth factor (CTGF) plays an important role in the renal fibrosis. Also, It is known that ERK phosphorylates the linker region of Smad3 to enhance and activity of ERK is increased in ADPKD. Here, we study whether CTGF is regulated by TGF-β and ERK via Smad2/3 signal pathway in ADPKD.

Methods

To examine the expression of CTGF and phosphorylation of Smad2/3, we performed immunohistochemistry(IHC) and Western blot of ADPKD kidney tissues and isolated cyst cells. To investigate whether Smad2/3 signal pathway was involved in the upregulation of CTGF and the role of ERK in Smad2/3 pathway, we treated A83-01, which blocked phosphorylation of Smad2/3, and ERK inhibitor, PD98059, into cyst cells. Next, we performed ELISA and RT-PCR to examine which TGF-β induced Smad2/3 pathway in ADPKD.

Results

In kidney tissues and isolated cyst cells of ADPKD patients, we found that expression of CTGF and phosphorylation of Smad2/3 were increased. The expression of CTGF and nuclear localization of phospho-Smad3 were reduced on treatment of A83-01. Thus, Smad2/3 pathway induced the expression of CTGF. We found that TGF-β2 was secreted and mRNA of TGF-β2 was increased in cyst cells. On the treatment of TGF-β2, phosphorylation of Smad2/3 and expression of CTGF were increased. When we treated ERK inhibitor, PD98059, it was found that nuclear phospho-Smad2/3 was reduced in nuclear/cytosol fractionation and immunofluorescence. Next, we study whether PC1 repressed TGF-β2 via AKT. IMCD cells expressing PC1 showed that secretion and mRNA of TGF-β2 were reduced. After treatment AKT inhibitor, the secretion and mRNA of TGF-β2 were increased indicating PC1 downregulated TGF-β2 via AKT.

Conclusion

Taken together, our results suggested that CTGF was regulated by TGF-β2 and ERK via Smad2/3 signal pathway in pericystic fibrosis of ADPKD.

Funding

  • Government Support - Non-U.S.