Non-alcoholic fatty liver disease is one of the main causes of chronic liver disease and therefore is currently considered a major public health problem. Sirtuin 1 (SIRT1) is an NAD-dependent deacetylase enzyme that contributes in the regulation of metabolic processes and protects against lipid accumulation in hepatocytes. Its expression is potentially regulated by microRNAs which attach to the 3′ untranslated region (3′-UTR) of their target mRNA. HepG2 cells were incubated by glucose to induce lipid accumulation and were subsequently transfected with mir-23b mimic and inhibitor. Real-time PCR was used for measuring the expression of mir-23b and SIRT1 mRNA. Cell survival assay and intracellular triglyceride measurement were performed using colorimetric methods. Determination of SIRT1 protein level and activity were done by western blot and fluorometric analysis, respectively. The interaction of miR-23b with 3′-UTR of SIRT1 mRNA was confirmed by dual luciferase. miR-23b mimic inhibited gene and protein expression of SIRT1, while the inhibitor of miR-23b significantly elevated the expression levels of SIRT1 mRNA and protein. The results showed that the 3′-UTR of SIRT1 mRNA is a direct target for miR-23b. The intracellular triglyceride level was increased following the inhibition of SIRT1 in transfected HepG2 cell by miR-23b mimic. Cell viability was decreased in response to miR-23b upregulation compared to control cells. miR-23b reduces the expression and activity of SIRT1 and therefore may be a causative factor in the enhancement of lipid accumulation in HepG2 cells.

中文翻译：

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mir-23b对SIRT1表达的下调有助于HepG2细胞中的脂质蓄积。

非酒精性脂肪肝是慢性肝病的主要原因之一，因此目前被认为是主要的公共卫生问题。Sirtuin 1（SIRT1）是NAD依赖的脱乙酰基酶，有助于调节代谢过程并防止脂质在肝细胞中的积累。它的表达可能受附着在其靶mRNA的3'非翻译区（3'-UTR）的microRNA调控。HepG2细胞用葡萄糖孵育以诱导脂质蓄积，随后用mir-23b模拟物和抑制剂转染。实时PCR被用于测量mir-23b和SIRT1 mRNA的表达。使用比色法进行细胞存活测定和细胞内甘油三酸酯测量。通过蛋白质印迹和荧光分析分别测定SIRT1蛋白水平和活性。通过双重荧光素酶证实了miR-23b与SIRT1 mRNA 3'-UTR的相互作用。miR-23b模拟物抑制SIRT1的基因和蛋白质表达，而miR-23b的抑制剂显着提高SIRT1 mRNA和蛋白质的表达水平。结果表明，SIRT1 mRNA的3'-UTR是miR-23b的直接靶标。miR-23b模拟物在转染的HepG2细胞中抑制SIRT1后，细胞内甘油三酯水平升高。与对照细胞相比，响应miR-23b上调的细胞活力降低了。miR-23b降低了SIRT1的表达和活性，因此可能是HepG2细胞脂质蓄积增加的原因。通过双重荧光素酶证实了miR-23b与SIRT1 mRNA 3'-UTR的相互作用。miR-23b模拟物抑制SIRT1的基因和蛋白质表达，而miR-23b的抑制剂显着提高SIRT1 mRNA和蛋白质的表达水平。结果表明，SIRT1 mRNA的3'-UTR是miR-23b的直接靶标。miR-23b模拟物在转染的HepG2细胞中抑制SIRT1后，细胞内甘油三酯水平升高。与对照细胞相比，响应miR-23b上调的细胞活力降低了。miR-23b降低了SIRT1的表达和活性，因此可能是HepG2细胞中脂质蓄积增加的原因。通过双重荧光素酶证实了miR-23b与SIRT1 mRNA 3'-UTR的相互作用。miR-23b模拟物抑制SIRT1的基因和蛋白质表达，而miR-23b的抑制剂显着提高SIRT1 mRNA和蛋白质的表达水平。结果表明，SIRT1 mRNA的3'-UTR是miR-23b的直接靶标。miR-23b模拟物在转染的HepG2细胞中抑制SIRT1后，细胞内甘油三酯水平升高。与对照细胞相比，响应miR-23b上调的细胞活力降低了。miR-23b降低了SIRT1的表达和活性，因此可能是HepG2细胞中脂质蓄积增加的原因。而miR-23b抑制剂可显着提高SIRT1 mRNA和蛋白的表达水平。结果表明，SIRT1 mRNA的3'-UTR是miR-23b的直接靶标。miR-23b模拟物在转染的HepG2细胞中抑制SIRT1后，细胞内甘油三酯水平升高。与对照细胞相比，响应miR-23b上调的细胞活力降低了。miR-23b降低了SIRT1的表达和活性，因此可能是HepG2细胞中脂质蓄积增加的原因。而miR-23b抑制剂可显着提高SIRT1 mRNA和蛋白的表达水平。结果表明，SIRT1 mRNA的3'-UTR是miR-23b的直接靶标。miR-23b模拟物在转染的HepG2细胞中抑制SIRT1后，细胞内甘油三酯水平升高。与对照细胞相比，响应miR-23b上调的细胞活力降低了。miR-23b降低了SIRT1的表达和活性，因此可能是HepG2细胞中脂质蓄积增加的原因。与对照细胞相比，响应miR-23b上调的细胞活力降低了。miR-23b降低了SIRT1的表达和活性，因此可能是HepG2细胞脂质蓄积增加的原因。与对照细胞相比，响应miR-23b上调的细胞活力降低了。miR-23b降低了SIRT1的表达和活性，因此可能是HepG2细胞中脂质蓄积增加的原因。