Shin Takasawa, Japan
Nara Medical University BiochemistryPresenter of 1 Presentation
EXPRESSION OF HUMAN REG IV GENE IN INFLAMMATORY BOWEL DISEASES AND ITS POSSIBLE MECHANISM
Abstract
Background and Aims
The pathophysiology of inflammatory bowel diseases (IBD) reflects a balance between mucosal injury and reparative mechanisms. Some regenerating gene (Reg) family members (REG Iα, REG Iβ, and REG IV) are expressed in Crohn’s disease (CD) and ulcerative colitis (UC) and involved as proliferative mucosal factors in IBD. We revealed that REG Iαand REG Iβ were induced by IL-6/IL-22 via MZF1, RTEF1/TEAD4, and STAT3 in REG Iα and HLTF/FOXN2F in REG Iβ, respectively. Although REG IV was up-regulated in IBD biopsy samples, the up-regulation of REG IV was not at all observed in cell culture system by autoimmune-related cytokines such as IL-6, IL-8, IL-17A, IL-22, TNFα, HGF, bFGF, and EGF.
Methods
Here, we analyzed REG IV expression in LS-174T and HT-29 human colonic epithelial cells by real-time RT-PCR and ELISA.
Results
REG IV expression was induced by lipopolysaccharide (LPS) in both cells. However, LPS did not activate REG IVpromoter (-1,053~+22) activity. As the LPS-induced up-regulation of REG IV was considered to be regulated post-transcriptionally, we searched targeted microRNA (miR) using the MicroRNA.org program (http://www.microrna.org/microrna/home.do), which revealed that REG IV mRNA have a potential target sequence for miR-24. We measured the miR-24 level of LPS-treated cells by RT-PCR and found that the level was significantly lower (0.0278±0.00665 fold in LS-174T cells [P=0.0368]; 0.1400±0.0618 fold in HT-29 cells [P=0.0490]).
Conclusions
The LPS-induced increase of REG IV mRNA was abolished by the introduction of miR-24 mimic but not by non-specific control RNA in both LS-174T and HT-29 cells.