[Effects of Vitamin D Receptor on Mucosal Barrier Proteins in Colon Cells under Hypoxic Environment]

To investigate the expressions of mucosal barrier proteins in colon cell line DLD-1 under hypoxic environment in vitro and its mechanism. Methods After DLD-1 cells were treated separately with hypoxia(l% O₂),vitamin D(100 nmol/L),or vitamin D plus hypoxia for 48 hours,the expressions of vitamin D receptor(VDR),tight junction proteins zonula occludens-1(ZO-1),occludin,Claudin-1,and adherent junction protein(E-cadherin)were determined by Western blot.Stable VDR knock-down(Sh-VDR)DLD-1 cell line and control DLD-1 cell line were established by lentivirus package technology and the protein expressions after hypoxia treatment were detected. Results Compared with control group,the expressions of occludin,Claudin-1,and VDR increased significantly after hypoxia treatment(all P<0.001).In addition to the protein expressions of occludin,Claudin-1 and VDR,the expressions of ZO-1 and E-cadherin were also obviously higher in vitamin D plus hypoxia group than in single vitamin D treatment group(all P<0.001).After hypoxia treatment,Sh-VDR cell line showed significantly decreased expressions of ZO-1(P<0.001),occludin(P<0.05),Claudin-1(P<0.01)and E-cadherin(P<0.001)when compared with untreated Sh-VDR cell line. Conclusion VDR acts as a regulator for the expressions of intestinal mucosal barrier proteins under hypoxia environment in DLD-1 colon cell line,indicating that VDR pathway may be another important protective mechanism for gut barrier in low-oxygen environment.