已知七种哺乳动物硒蛋白位于内质网中:SELENOM,SELENOT,SELENOF,SELENOK,SELENOS,SELENON,和DIO2。其中,SELENOM和SELENOT是研究最少的;因此,使用广泛的方法来抑制编码这些蛋白质的基因的表达以及通过RNA干扰来抑制酶本身的活性的方法来研究它们的功能是非常有意义的。我们已经表明,在A-172人胶质母细胞瘤细胞系中SELENOM和SELENOTmRNA的表达减少超过10倍,酶的定量含量减少超过3倍导致ER应激,表示为存储Ca2离子的ER容量降低。在调节凋亡过程的水平,SELENOM敲除导致促凋亡CHOP的表达增加,GADD34,PUMA,还有BIM基因,但是谷胱甘肽过氧化物酶和硫氧还蛋白组的SELENOT和抗氧化基因水平的代偿性增加并没有诱导细胞死亡。SELENOT的击倒产生了相反的效果,减少促凋亡蛋白的表达和调节少量编码抗氧化酶的基因的水平,这也不影响所研究细胞中细胞凋亡的基线水平。同时,MSA或SeNPs诱导的ER应激通过抑制含硒抗氧化蛋白的表达在SELENOT敲低细胞中诱导更明显的促凋亡作用。因此,在这项工作中,第一次,细胞凋亡过程的精细调节机制,细胞增殖,和两种内质网驻留蛋白的内质网应激,SELENOM和SELENOT,被感动了,这不仅是基本的,而且由于细胞的钙信号传导系统之间的密切关系,折叠蛋白-细胞凋亡和细胞存活途径的调节因子。
It is known that seven mammalian selenoproteins are localized in the endoplasmic reticulum: SELENOM, SELENOT, SELENOF, SELENOK, SELENOS, SELENON, and DIO2. Among them, SELENOM and SELENOT are the least studied; therefore, the study of their function using the widespread method of suppressing the expression of genes encoding these proteins and the activity of the enzymes themselves by RNA interference is of great interest. We have shown that a decrease in the expression of SELENOM and SELENOT mRNA in the A-172 human glioblastoma cell line by more than 10 times and the quantitative content of enzymes by more than 3 times leads to ER stress, expressed as a decrease in the ER capacity for storing Ca2+ ions. At the level of regulation of apoptotic processes, SELENOM knockdown leads to an increase in the expression of pro-apoptotic CHOP, GADD34, PUMA, and BIM genes, but a compensatory increase in the levels of SELENOT and antioxidant genes from the group of glutathione peroxidases and thioredoxins did not induce cell death. Knockdown of SELENOT had the opposite effect, reducing the expression of pro-apoptotic proteins and regulating the level of a smaller number of genes encoding antioxidant enzymes, which also did not affect the baseline level of apoptosis in the studied cells. At the same time, ER stress induced by MSA or SeNPs induced a more pronounced pro-apoptotic effect in SELENOT knockdown cells through suppression of the expression of selenium-containing antioxidant proteins. Thus, in this work, for the first time, the mechanisms of fine regulation of the processes of apoptosis, cell proliferation, and ER stress by two ER resident proteins, SELENOM and SELENOT, are touched upon, which is not only fundamental but also applied to clinical importance due to the close relationship between the calcium signaling system of cells, folding proteins-regulators of apoptosis and cell survival pathways.