Regulation of hypoxia inducible factor-1α on permeability of vascular endothelial cells and the mechanism / 中华烧伤杂志

Objective@#To investigate the regulation of hypoxia-inducible factor-1α (HIF-1α) on permeability of rat vascular endothelial cells and the mechanism.@*Methods@#Twelve male Sprague-Dawley rats aged 35 to 38 days were collected and vascular endothelial cells were separated and cultured. The morphology of cells was observed after 4 days of culture, and the following experiments were performed on the 2nd or 3rd passage of cells. (1) Rat vascular endothelial cells were collected and divided into blank control group, negative control group, HIF-1α interference sequence 1 group, HIF-1α interference sequence 2 group, and HIF-1α interference sequence 3 group according to the random number table (the same grouping method below), with 3 wells in each group. Cells in negative control group, HIF-1α interference sequence 1 group, HIF-1α interference sequence 2 group, and HIF-1α interference sequence 3 group were transfected with GV248 empty plasmid, recombinant plasmid respectively containing HIF-1α interference sequence 1, interference sequence 2, and interference sequence 3 with liposome 2000. Cells in blank control group were only transfected with liposome 2000. After transfection of 24 h, expression levels of HIF-1α mRNA and protein of cells in each group were respectively detected by reverse transcription real-time fluorescent quantitative polymerase chain reaction and Western blotting (the same detecting methods below) . The sequence with the highest interference efficiency was selected. (2) Another batch of rat vascular endothelial cells were collected and divided into blank control group, negative control group, and HIF-1α low expression group, with 3 wells in each group. Cells in blank control group were only transfected with liposome 2000, and cells in negative control group and HIF-1α low expression group were respectively transfected with GV248 empty plasmid and low expression HIF-1α recombinant plasmid selected in experiment (1) with liposome 2000. After 14 days of culture, the mRNA and protein expressions of HIF-1α in each group were detected. (3) Another batch of rat vascular endothelial cells were collected and divided into blank control group, negative control group, and HIF-1α high expression group, with 3 wells in each group. Cells in blank control group were transfected with liposome 2000, and cells in negative control group and HIF-1α high expression group were respectively transfected with GV230 empty plasmid and HIF-1α high expression recombinant plasmid with liposome 2000. After 14 days of culture, the mRNA and protein expressions of HIF-1α of cells in each group were detected. (4) After transfection of 24 h, cells of three groups in experiment (1) and three groups in experiment (2) were collected, and mRNA and protein expressions of myosin light chain kinase (MLCK), phosphorylated myosin light chain (p-MLC), and zonula occludens 1 (ZO-1) of cells were detected. Data were processed with one-way analysis of variance and t test.@*Results@#After 4 days of culture, the cells were spindle-shaped, and rat vascular endothelial cells were successfully cultured. (1) The interference efficiencies of HIF-1α of cells in HIF-1α interference sequence 1 group, HIF-1α interference sequence 2 group, and HIF-1α interference sequence 3 group were 47.66%, 45.79%, and 62.62%, respectively, and the interference sequence 3 group had the highest interference efficiency. After transfection of 24 h, the mRNA and protein expression levels of HIF-1α of cells in interference sequence 3 group were significantly lower than those in blank control group (t=18.404, 9.140, P<0.01) and negative control group (t=15.099, 7.096, P<0.01). (2) After cultured for 14 days, the mRNA and protein expression levels of HIF-1α of cells in HIF-1α low expression group were significantly lower than those in blank control group (t=21.140, 5.440, P<0.01) and negative control group (t= 14.310, 5.210, P<0.01). (3) After cultured for 14 days, the mRNA and protein expression levels of HIF-1α of cells in HIF-1α high expression group were significantly higher than those in blank control group (t=19.160, 7.710, P<0.01) and negative control group (t= 19.890, 7.500, P<0.01). (4) After transfection of 24 h, the mRNA expression levels of MLCK and p-MLC of cells in HIF-1α low expression group were significantly lower than those in blank control group (t=2.709, 4.011, P<0.05 or P<0.01) and negative control group (t=2.373, 3.744, P<0.05 or P<0.01). The mRNA expression level of ZO-1 of cells in HIF-1α low expression group was significantly higher than that in blank control group and negative control group (t=4.285, 5.050, P<0.01). The mRNA expression levels of MLCK and p-MLC of cells in HIF-1α high expression group were significantly higher than those in blank control group (t=9.118, 11.313, P<0.01) and negative control group (t=9.073, 11.280, P<0.01). The mRNA expression level of ZO-1 of cells in HIF-1α high expression group was significantly lower than that in blank control group and negative control group (t=2.889, 2.640, P<0.05). (5) After transfection of 24 h, the protein expression levels of MLCK and p-MLC of cells in HIF-1α low expression group were significantly lower than those in blank control group (t=2.652, 3.983, P<0.05 or P<0.01) and negative control group (t=2.792, 4.065, P<0.05 or P<0.01). The protein expression of ZO-1 of cells in HIF-1α low expression group was significantly higher than that in blank control group and negative control group (t=3.881, 3.570, P<0.01). The protein expression levels of MLCK and p-MLC of cells in HIF-1α high expression group were 1.18±0.24 and 0.68±0.22, which were significantly higher than 0.41±0.21 and 0.35±0.14 in blank control group (t=5.011, 3.982, P<0.05 or P<0.01) and 0.43±0.20 and 0.36±0.12 in negative control group (t= 4.880, 3.862, P<0.05 or P<0.01). The protein expression level of ZO-1 of cells in HIF-1α high expression group was 0.08±0.06, which was significantly lower than 0.20±0.09 in blank control group and 0.19±0.09 in negative control group (t=4.178, 3.830, P<0.05 or P<0.01).@*Conclusions@#HIF-1α up-regulates expressions of MLCK and p-MLC and down-regulates expression of ZO-1, thereby increasing the permeability of rat vascular endothelial cells.

Immunoexpression of HIF-1α and VEGF in Periodontal Disease and Healthy Gingival Tissues

Abstract Hypoxia-inducible factor 1 alpha (HIF-1α) and vascular endothelial growth factor (VEGF) are proteins that stimulate the proliferation and migration of endothelial cells. These proteins have been described in many pathologic and inflammatory conditions, but their involvement in the development of periodontitis has not been thoroughly investigated. This study compared the immunohistochemical expression of these proteins, involved in angiogenesis and hypoxia, by imunnostained inflammatory and endothelial cells in periodontal disease and healthy gingival tissues. Gingival tissue samples were divided as follows: 30 samples with chronic periodontitis, 30 with chronic gingivitis, and 30 of healthy gingiva. Results were analyzed statistically by the Kruskal-Wallis, Mann-Whitney and Spearman correlation tests (p=0.01). Inflammatory and endothelial cells were found to express these proteins. Periodontitis showed median percentage of HIF-1α-positive cells of 39.6%, 22.0% in cases of gingivitis and 0.9% in the healthy gingiva group (p=0.001). For VEGF, median percentage of immunopositive cells was 68.7% for periodontitis, 66.1% in cases for gingivitis, and 19.2% for healthy gingival specimens (p<0.001). Significant correlation between VEGF and HIF-1α was also observed in healthy gingiva (p<0.001).The increased expression of HIF-1αα and VEGF in periodontitis, compared to gingivitis and healthy gingiva, suggests possible activation of the HIF-1α pathway in advanced periodontal disease. The correlation between HIF-1α and VEGF expression in healthy gingiva suggests a physiological function for these proteins in conditions of homeostasis. In periodontal disease, HIF-1 and VEGF expression may be regulated by other factors, in addition to hypoxia, such as bacterial endotoxins and inflammatory cytokines.

Resumo O fator induzível por hipóxia 1 alfa (HIF-1α) e o fator de crescimento endotelial vascular (VEGF) são proteínas que estimulam a proliferação e a migração de células endoteliais. Estas proteínas têm sido descritas em muitas condições patológicas e inflamatórias, mas o envolvimento dessas no desenvolvimento de periodontite não foi completamente investigado. Este estudo comparou a expressão imunohistoquímica destas proteínas, envolvidas na angiogênese e hipóxia, na doença periodontal e em tecidos gengivais saudáveis por meio de contagem de células inflamatórias e endoteliais imunomarcadas. As amostras de tecido gengival foram divididas da seguinte forma: 30 amostras com periodontite crônica, 30 com gengivite crônica e 30 de gengiva saudável. Os resultados foram analisados estatisticamente pelos testes de Kruskal-Wallis e Mann-Whitney (p=0.01). As células inflamatórias e endoteliais foram positivas para estas proteínas. A porcentagem média de células positivas para HIF-1α foi de 39,6% nos casos de periodontite, 22,0% nos casos de gengivite e de 0,9% no grupo de gengiva saudável (p = 0,001). A porcentagem média de células imunopositivas para o VEGF foi de 68,7% nos casos de periodontite, 66,1% nos casos de gengivite, e 19,2% em espécimes gengivais saudáveis (p<0,001). Correlação significativa entre o VEGF e HIF-1α foi observada em gengival. A expressão elevada do HIF-1α e VEGF em periodontite, comparada a gengivite e gengiva saudável, sugere ativação da via do HIF-1α, na doença periodontal avançada. A correlação entre o HIF-1α e expressão de VEGF na gengiva saudável, sugere uma função fisiológica para estas proteínas em condições de homeostase. Na doença periodontal, a expressão de HIF-1α e VEGF pode ser regulada por outros fatores, além da hipóxia, tais como endotoxinas bacterianas e citocinas inflamatórias.

Effects of hypoxia inducible factor-1 alpha-targeting small interfering RNA on vascular endothelial growth factor gene expression in HaCaT cells / 中华皮肤科杂志

ObjectiveTo observe the effects of hypoxia inducible factor-1 alpha (HIF-1α)-targeting small interfering RNA(siRNA) on the expression of HIF-1α and vascular endothelial growth factor (VEGF) in HaCaT ceils under hypoxic conditions. MethodsHaCaT cells were cultured and divided into four groups, normal control group (without any treatment), hypoxia group (cultured under hypoxic conditions for 24 hours),liposome control group (transfected with liposome followed by hypoxic culture for 24 hours), RNA interference group (transfected with HIF-1α-targeting siRNA/liposome complexes followed by hypoxic culture for 24 hours). Fluorescence real-time quantitative PCR was utilized to determine HIF-1oα and VEGF mRNA expression in HaCaT cells, and Western blot to detect HIF-1α and VEGF protein expression. ResultsNo significant difference was observed in the mRNA expression of HIF-1α between the hypoxia group and normal control group(0.907 ± 0.032 vs. 0.878 ± 0.034, F =1.108, P ＞ 0.05), while the expression levels of VEGF mRNA,HIF-1α and VEGF proteins were significantly higher in the hypoxia group than in the normal control group (0.935 ± 0.032 vs. 0.652 ± 0.053, 0.813 ± 0.047 vs. 0.236 ± 0.014, 0.791 ± 0.030 vs. 0.316 ± 0.013, all P ＜0.05). A significant decline was noted in the mRNA and protein expression levels of VEGF (0.230 ± 0.044 vs.0.978 ± 0.030, 0.213 ± 0.026 vs. 0.817 ± 0.049, both P ＜ 0.05) and HIF-1α(0.497 ± 0.033 vs. 0.806 ±0.040, 0.249 ± 0.028 vs. 0.833 ± 0.052, both P ＜ 0.05) in the RNA interference group than in the liposome control group. ConclusionsHypoxia may enhance the expression of HIF-1α and VEGF in HaCaT cells, and to inhibit the HIF-1α expression may suppress the expression of VEGF in HaCaT cells under hypoxia.