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Human Intestinal Ste20‐related Proline/alanine Kinase (SPAK): A Novel Regulator of Intestinal Inflammation
Author(s) -
Yan Yutao,
Dalmasso Guillaume,
CharrierHisamuddin Laetitia,
Nguyen Hang,
Sitaraman Shanthi V,
Merlin Didier
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.1183.1
Subject(s) - kinase , regulator , microbiology and biotechnology , messenger rna , inflammatory bowel disease , promoter , transcriptional regulation , chemistry , biology , gene expression , biochemistry , gene , medicine , disease
We have recently cloned and characterized a new intestinal inflammation associated ste20‐related protein kinase isoform (SPAK). Here we investigate its express and regulation during inflammatory bowel disease. Real time PCR‐based analysis suggested high expression of SPAK in colonic tissue from IBD patients and DSS mouse colitis compared to normal control colonic tissue. We then isolated the SPAK core promoter. Two transcriptional initiation sites were mapped by primer extension and 5′‐RACE. Direct sequencing of the promoter revealed it a promoter with one NF‐?B and three Sp1 binding sites, but no TATA box. Using EMSA, CHIP, and Luciferase assay, we demonstrated that NF‐?B binding site was essential for stimulated SPAK promoter activity by TNF‐a, whereas Sp1 binding sites were important for the basal promoter activity. Western blots of Caco2‐BBE cells treated with siRNA of Sp1 and NF‐?B demonstrated that knock‐down of NF‐?B but not of Sp1 reduces the SPAK level. By mRNA decay assay, we found that TNF‐a increases SPAK transcripts without affecting its mRNA stability. Microarray analysis demonstrated SPAK can target key inflammatory signaling pathways such as p38, JNK. These findings collectively indicate that the SPAK is expressed during active inflammatory bowel disease in human as well as animal models. TNF‐a is a key regulator of SPAK expression.