【摘要】 为研究miR-21对奶山羊乳腺上皮细胞(goat mammary epithelial cells, GMECs)增殖及乳成分调控作用的影响，将miR-21 mimics、inhibitors转染至GMECs,通过EdU、CCK-8、ELISA、RT-qPCR、Western Blot等试验检测miR-21对GMECs增殖凋亡相关基因Bcl-2、Bax的表达量及β-酪蛋白和甘油三酯(TG)合成的影响。结果表明，抑制miR-21后，GMECs活力极显著降低(P<0.01),GMECs的凋亡水平极显著升高(P<0.01),而miR-21 mimics组GMECs活力则显著升高(P<0.05);转染miR-21 mimics后，GMECs中β-酪蛋白和TG的分泌量极显著升高(P<0.01),抑制miR-21后，GMECs中β-酪蛋白和TG的分泌量极显著降低(P<0.01);与对照组相比，miR-21 mimics组PI3K、mTOR、S6K、ERK蛋白的磷酸化极显著升高(P<0.01), Bax蛋白表达则极显著抑制(P<0.01), Bcl-2蛋白表达水平极显著上调(P<0.01),抑制miR-21后，PI3K、mTOR、S6K、ERK的蛋白磷酸化显著降低(P<0.05), Bax蛋白的表达极显著上调(P<0.01),同时Bcl-2的蛋白表达显著下调(P<0.05)。上述结果表明，miR-21通过激活ERK/Bcl-2/Bax信号通路抑制了奶山羊乳腺上皮细胞的调亡，并通过激活PI3K/mTOR/S6K信号通路促进奶山羊乳腺上皮细胞中β-酪蛋白和TG的分泌。更多还原

【Abstract】 To investigate the regulatory effects of miR-21 on the proliferation and milk component of goat mammary epithelial cells(GMECs), miR-21 mimics and inhibitors were transfected into GMECs. The expression levels of apoptosis-and prolifer ation-relates genes Bcl-21 and Bax, as well as the secretion of β-casein and triglgerides(TG),were examined using EdU, CCK-8, ELISA, RT-qPCR, and Western Blot. Results indicated that the viability of GMECs in the miR-21 inhibitor group was significantly reduced(P<0.01), while apoptosis levels were significantly increased(P<0.01). In contrast, the viability of GMECs was significantly increased in the miR-21 mimics group(P<0.05). There was a significant increase in the secretion of β-casein and TG in GMECs transfected with miR-21 mimics(P<0.01), whereas interference with miR-21 inhibitors significantly decreased the secretion of β-casein and TG in GMECs(P<0.01). Compared with the control group, phosphorylation of PI3K, mTOR, S6K, and ERK proteins significantly increased in the miR-21 mimics group(P<0.01). Bax protein expression was significantly suppressed(P<0.01), while Bcl-2 protein expression was significantly upregulated(P<0.01). In the miR-21 inhibitors group, the phosphorylation of PI3K, mTOR, S6K, and ERK proteins significantly decreased(P<0.05), Bax protein expression was significantly upregulated(P<0.01), and Bcl-2 protein expression was significantly downregulated(P<0.05). The results indicate that miR-21 suppresses apoptosis in goat mammary epithelial cells by activating the ERK/Bcl-2/Bax signaling pathway and promotes the secretion of β-casein and TG through activation of the PI3K/mTOR/S6K signaling pathway.更多还原