Open AccessNovel lnc RNA regulated by HIF‐1 inhibits apoptotic cell death in the renal tubular epithelial cells under hypoxia
Author(s) -
Mimura Imari,
Hirakawa Yosuke,
Kanki Yasuharu,
Kushida Natsuki,
Nakaki Ryo,
Suzuki Yutaka,
Tanaka Tetsuhiro,
Aburatani Hiroyuki,
Nangaku Masaomi
Publication year - 2017
Publication title -
physiological reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 39
ISSN - 2051-817X
DOI - 10.14814/phy2.13203
Subject(s) - gene knockdown , hypoxia (environmental) , biology , hypoxia inducible factors , rna , microbiology and biotechnology , apoptosis , small interfering rna , kidney , messenger rna , cell culture , gene , cancer research , chemistry , biochemistry , genetics , organic chemistry , oxygen
Chronic tubulointerstitial hypoxia plays an important role as the final common pathway to end‐stage renal disease. HIF ‐1 (hypoxia‐inducible factor‐1) is a master transcriptional factor under hypoxia, regulating downstream target genes. Genome‐wide analysis of HIF ‐1 binding sites using high‐throughput sequencers has clarified various kinds of downstream targets and made it possible to demonstrate the novel roles of HIF ‐1. Our aim of this study is to identify novel HIF ‐1 downstream epigenetic targets which may play important roles in the kidney. Immortalized tubular cell lines ( HK 2; human kidney‐2) and primary cultured cells ( RPTEC ; renal proximal tubular cell lines) were exposed to 1% hypoxia for 24–72 h. We performed RNA ‐seq to clarify the expression of mRNA and long non‐coding RNA (lnc RNA ). We also examined Ch IP ‐seq to identify HIF ‐1 binding sites under hypoxia. RNA ‐seq identified 44 lnc RNA s which are up‐regulated under hypoxic condition in both cells. Ch IP ‐seq analysis demonstrated that HIF ‐1 also binds to the lnc RNA s under hypoxia. The expression of novel lnc RNA , DARS ‐ AS 1 (aspartyl‐ tRNA synthetase anti‐sense 1), is up‐regulated only under hypoxia and HIF ‐1 binds to its promoter region, which includes two hypoxia‐responsive elements. Its expression is also up‐regulated with cobalt chloride exposure, while it is not under hypoxia when HIF ‐1 is knocked down by si RNA . To clarify the biological roles of DARS ‐ AS 1, we measured the activity of caspase 3/7 using anti‐sense oligo of DARS ‐ AS 1. Knockdown of DARS ‐ AS 1 deteriorated apoptotic cell death. In conclusion, we identified the novel lnc RNA s regulated by HIF ‐1 under hypoxia and clarified that DARS ‐ AS 1 plays an important role in inhibiting apoptotic cell death in renal tubular cells.