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Kidney Week

Abstract: TH-PO475

Suppression of Transcription Factor OASIS Ameliorated Kidney Fibrosis

Session Information

  • CKD: Mechanisms - I
    November 07, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
    Abstract Time: 10:00 AM - 12:00 PM

Category: CKD (Non-Dialysis)

  • 2103 CKD (Non-Dialysis): Mechanisms

Authors

  • Obana, Masanori, Osaka University, OSAKA, Japan
  • Yamamoto, Ayaha, Osaka University, OSAKA, Japan
  • Nakae, Takafumi, Osaka University, OSAKA, Japan
  • Miyake, Yoshiaki, Osaka University, OSAKA, Japan
  • Harada, Takeo, Osaka University, OSAKA, Japan
  • Mitsuoka, Sayuri, Osaka University, OSAKA, Japan
  • Noda, Shunsuke, Osaka University, OSAKA, Japan
  • Maeda, Makiko, Osaka University, OSAKA, Japan
  • Imaizumi, Kazunori, Hiroshima University, Hiroshima, Japan
  • Matsumoto, Kotaro, Osaka University, OSAKA, Japan
  • Fujio, Yasushi, Osaka University, OSAKA, Japan
Background

Old astrocyte specifically induced substance (OASIS), a transcription factor, was originally identified as an ER stress transducer. We found that there was a correlation between OASIS mRNA expression and the severity of tubular atrophy and interstitial fibrosis in patients with kidney diseases, analyzed by Nephroseq database. However, the pathophysiological roles of OASIS in kidney remain to be elucidated. The aim of this study is to determine the functional roles of OASIS in the development of kidney fibrosis.

Methods

OASIS expression was investigated by immunohistochemistry, immunoblotting and quantitative PCR. To assess the functions of OASIS in (myo)fibroblast, NRK49F cells, rat renal fibroblasts, were transduced with the lentivirus encoding OASIS shRNA, followed by TGF-β1 treatment. Twenty-four hours after TGF-β1 treatment, wound healing assay and proliferation assay were performed. To examine the effects of OASIS on kidney fibrosis, OASIS knockout (KO) mice were subjected to unilateral ureteral obstruction (UUO). At day 7 after UUO, Masson’s trichrome stain and hydroxyproline assay were performed. To explore the downstream molecules of OASIS, DNA microarray was performed on OASIS KO myofibroblasts. Anti-bone marrow stromal antigen (Bst2) antibody was injected into mice at day 1 after UUO.

Results

The protein level of OASIS was increased in human fibrotic kidney. Consistently, mRNA and protein levels of OASIS were upregulated in UUO-induced murine fibrotic kidney. In addition, the number of OASIS-expressed myofibroblasts were elevated after UUO. OASIS expression was induced by TGF-β1 in NRK49F cells. OASIS knockdown suppressed TGF-β1-induced migration and proliferation of NRK49F cells. Moreover, kidney fibrosis was attenuated in OASIS KO mice (HP content (µg/mg): Wild type-UUO; 0.48±0.08, OASIS KO-UUO; 0.38±0.05, n=7, p<0.05). DNA microarray revealed that Bst2 was a candidate downstream molecule of OASIS. Finally, antibody blockade of Bst2 ameliorated kidney fibrosis after UUO (HP content (µg/mg): control IgGκ; 0.60±0.08, anti-Bst2 antibody; 0.49±0.09, n=6, p<0.05).

Conclusion

OASIS exacerbated kidney fibrosis in part by increased Bst2 expression. Suppression of OASIS could be a novel therapeutic strategy against chronic kidney disease.