环状RNA circFADS2在脓毒症中表达下调，并通过下调miR-133a保护肺细胞免受脂多糖诱导的细胞凋亡。
CircRNA circFADS2 is under-expressed in sepsis and protects lung cells from LPS-induced apoptosis by downregulating miR-133a.
作者信息
Niu Fang, Liang Xiaofeng, Ni Jindi, Xia Zhuye, Jiang Lijing, Wang Hong, Liu Hongjie, Shen Guofeng, Li Xiang
机构信息
Department of Critical Care Medicine, Second Hospital of Lanzhou University, 730000, Lanzhou City, Gansu Province, P. R. China.
Department of Infectious Diseases, Jiujiang Maternal & Child Health Care Hospital, 332000, Jiujiang City, Jiangxi Province, P. R. China.
出版信息
J Inflamm (Lond). 2022 Mar 12;19(1):4. doi: 10.1186/s12950-022-00300-3.
BACKGROUND
It has been reported that hsa_circRNA_100833 (identified as circFADS2) and miR-133a play opposite roles in LPS-induced cell apoptosis, which contributes to the development of sepsis. This study was carried out to explore the interaction between circFADS2 and miR-133a in sepsis.
METHODS
Expression of circFADS2 and miR-133a in plasma from both sepsis patients (n=62) and healthy controls (n=62) was studied by RT-qPCR. Pearson's correlation coefficient analysis was utilized to analyze the correlation between circFADS2 and miR-133a levels across plasma samples from sepsis patients. Cell viability and apoptosis, levels of proteins associated with apoptosis (cleaved caspase-3 and cleaved caspase-9), and expression of pro-inflammatory cytokines in LPS-treated HBEpCs were detected by MTT assay, cell apoptosis assay, western blot, and ELISA, respectively. In addition, a dual-luciferase reporter assay was performed to verify the interaction between circFADS2 and miR-133a.
RESULTS
CircFADS2 was under-expressed (0.56-fold vs. control) in sepsis, and miR-133a was highly expressed (2.05-fold vs. control) in sepsis. An inverse correlation between circFADS2 and miR-133a was observed across sepsis samples. LPS decreased cell viability, increased cell apoptosis, and elevated productions of tumor necrosis factor (TNF)-α, interleukins (IL)-1β, IL-6, and IL-8 in HBEpCs in a dose-dependent manner. In addition, circFADS2 was identified as a target gene of miR-133a. The further experiment revealed that circFADS2 overexpression and miR-133a inhibition prominently promoted cell viability (1.71-fold vs. pcDNA3.1; 1.65-fold vs. NC miRNA) and decreased apoptosis of LPS-treated HBEpCs (0.44-fold vs. pcDNA3.1; 0.47-fold vs. NC miRNA). Moreover, circFADS2 knockdown and miR-133a overexpression inhibited viability (0.36-fold vs. pcDNA3.1; 0.37-fold vs. NC miRNA) and increased apoptosis (1.54-fold vs. pcDNA3.1; 1.51-fold vs. NC miRNA) of LPS-treated HBEpCs. Notably, circFADS2 overexpression reduced the effects of miR-133a on LPS-treated HBEpCs.
CONCLUSIONS
CircFADS2 is under-expressed in sepsis and may protect lung cells from LPS-induced apoptosis by downregulating miR-133a.
背景
据报道，hsa_circRNA_100833（被鉴定为circFADS2）和miR-133a在脂多糖（LPS）诱导的细胞凋亡中发挥相反作用，这与脓毒症的发展有关。本研究旨在探讨circFADS2与miR-133a在脓毒症中的相互作用。
方法
采用逆转录定量聚合酶链反应（RT-qPCR）研究脓毒症患者（n=62）和健康对照者（n=62）血浆中circFADS2和miR-133a的表达。利用Pearson相关系数分析脓毒症患者血浆样本中circFADS2和miR-133a水平之间的相关性。分别通过MTT法、细胞凋亡检测、蛋白质免疫印迹法和酶联免疫吸附测定（ELISA）检测LPS处理的人支气管上皮细胞（HBEpCs）的细胞活力和凋亡、凋亡相关蛋白（裂解的半胱天冬酶-3和裂解的半胱天冬酶-9）水平以及促炎细胞因子的表达。此外，进行双荧光素酶报告基因检测以验证circFADS2与miR-133a之间的相互作用。
结果
circFADS2在脓毒症中表达下调（相对于对照为0.56倍），而miR-133a在脓毒症中高表达（相对于对照为2.05倍）。在脓毒症样本中观察到circFADS2与miR-133a呈负相关。LPS以剂量依赖性方式降低HBEpCs的细胞活力、增加细胞凋亡，并提高肿瘤坏死因子（TNF）-α、白细胞介素（IL）-1β、IL-6和IL-8的产生。此外，circFADS2被鉴定为miR-133a的靶基因。进一步实验表明，circFADS2过表达和miR-133a抑制显著促进细胞活力（相对于pcDNA3.1为1.71倍；相对于阴性对照miRNA为1.65倍），并减少LPS处理的HBEpCs的凋亡（相对于pcDNA3.1为0.44倍；相对于阴性对照miRNA为0.47倍）。此外，circFADS2敲低和miR-133a过表达抑制LPS处理的HBEpCs的活力（相对于pcDNA3.1为0.36倍；相对于阴性对照miRNA为0.37倍）并增加凋亡（相对于pcDNA3.1为1.54倍；相对于阴性对照miRNA为1.51倍）。值得注意的是，circFADS2过表达减弱了miR-133a对LPS处理的HBEpCs的影响。
结论
CircFADS2在脓毒症中表达下调，可能通过下调miR-133a保护肺细胞免受LPS诱导的凋亡。
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