Hypoxia-inducible factor 1α regulates the expression of CD18 and ninjurin-1

Objective To investigate the effects of hypoxia-inducible factor 1α (HIF-1α) small interfere RNA construct pSUPERH1-siHIF1α on the expression of CD18 and ninjurin 1 by K562 (human chronic myelogenous leukemia cell line) cells cultured with serums from patients with early stage of diabetic retinopathy.Methods K562 cells were cultured in 4 groups as control group (group A),diabetic group (group B),diabetes and pSUPERH1-siHIF1α transfect group (group C) and diabetes and pSUPER-retro transfect group (group D).The cells in group A were cultured in human serum from age-matched healthy control,and in group B,C and D,the cells were cultured in serum from the subjects of early stage of diabetic retinopathy.Twenty-four hours before the cells were cultured by the serum from the subjects of early stage of diabetic retinopathy,the HIF-1α specific siRNA expression vector pSUPERH1-siHIF1α and empty vector pSUPER-retro were transfected into the cells of group C and D,respectively.The percentages of CD18 and ninjurin-1 positive cell on the surface of K562 cells were measured by Flow Cytometry.The adherent rate between K562 and RF/6A was measured by the rose Bengal staining test.Results The percentages of CD18 positive cell in the group A,B,C and D were significantly different (F=14.33,P=0.01).The percentage of group B was significantly higher than that in group A (P=0.001) ; the percentage of group C was significantly lower than that in group B (P=0.001) and group D (P=0.02) ; the difference between group C and A was not significant (95％CI=-14.89-2.13,P=0.12).The differences of the percentage of ninjurin-1 positive cell among the group A,B,C and D were significant (F=39.38,P=0.001).The percentage of group B was significantly higher than that in group A (P=0.00); the difference of the percentage between group C and B was not significant (P =0.06),that was also not significant between group C and D (P=0.49).The differences of the adherent rate between K562 and RF/6A (rhesus monkey retinal choroid blood vessel endothelial cell line) among the group A,B,C and D were significant (F=20.62,P=0.00).The adherent rate of group B was significantly higher than that in group A (P=0.00),the adherent rate in group C was significantly lower than that in group B (P=0.01),but it was still significantly higher than that in group A (P=0.002),the difference of adherent rate between group B and D was not significant (P=0.68).Conclusion Under the early stage of diabetic retinopathy,HIF-1α small interfere RNA pSUPERH1-siHIF1α may significantly suppress the expression of CD18 on the surface of K562 cells,but it may not significantly influence the expression of ninjurin-1 on the surface of K562 cells. Key words: Diabetic retinopathy/pathophsiology;  Hypoxia-inducible factor 1, alpha subunit; RNA, small interfering