Ito Ichiaki, Asai Akira, Suzuki Sumihiro, Kobayashi Makiko, Suzuki Fujio
Department of Internal Medicine, The University of Texas Medical Branch, Galveston, TX, USA.
The Second Department of Internal Medicine, Osaka Medical College, Takatsuki, Osaka, Japan.
Biochem Biophys Res Commun. 2017 Nov 4;493(1):170-175. doi: 10.1016/j.bbrc.2017.09.053. Epub 2017 Sep 13.
Macrophages (Mϕ) are highly plastic and change their functional phenotypes depending on microenvironmental signals. Recent studies have shown that microRNAs are involved in the polarization of Mϕ. In this study, we demonstrated that the phenotype of M2bMϕ [CCL1(+) IL-10(+) LIGHT(+)] switches to other phenotypes with interchangeability attained through the increased expression of growth arrest-specific 5 RNA (GAS5 RNA), a long noncoding RNA. GAS5 RNA has been described as a silencer of the CCL1 gene. Various phenotypes of Mϕ were prepared from bone marrow-derived Mϕ (BMDMϕ) after stimulation with IFNγ [M(IFNγ)/M1Mϕ], IL-4 [M(IL-4)/M2aMϕ], LPS and immobilized IgG [M(LPS + IC)/M2bMϕ], and IL-10 [M(IL-10)/M2cMϕ]. BMDMϕ cultured with medium [M(no)/quiescent Mϕ] were used as a control. As compared to Μ(no), M(IFNγ), M(IL-4) and M(IL-10), the reduced level of GAS5 RNA was shown in M(LPS + IC). CCL1 and LIGHT mRNAs (typical biomarkers of M2bMϕ) were not expressed by M(LPS + IC) transduced with a GAS5 gene using lentiviral vector. The reduction of GAS5 RNA in M(LPS + IC) was mediated by the activation of nonsense-mediated RNA decay (NMD) pathway. BMDMϕ overexpressed with GAS5 RNA after GAS5 gene transduction did not polarize to M2bMϕ even though they were stimulated with LPS and IC in combination. These results indicate that the reduction of GAS5 RNA influenced by the NMD pathway activation leads to the Mϕ polarization stimulated with LPS and IC in combination.
巨噬细胞（Mϕ）具有高度可塑性，会根据微环境信号改变其功能表型。最近的研究表明，微小RNA参与了Mϕ的极化过程。在本研究中，我们证明了M2b Mϕ[CCL1(+) IL-10(+) LIGHT(+)]的表型可通过生长停滞特异性5 RNA（GAS5 RNA，一种长链非编码RNA）表达增加实现互换性转变为其他表型。GAS5 RNA被描述为CCL1基因的沉默子。在用IFNγ刺激后从骨髓来源的巨噬细胞（BMDMϕ）制备了各种Mϕ表型[M(IFNγ)/M1 Mϕ]、IL-4[M(IL-4)/M2a Mϕ]、LPS和固定化IgG[M(LPS + IC)/M2b Mϕ]以及IL-10[M(IL-10)/M2c Mϕ]。用培养基培养的BMDMϕ[M(无)/静止Mϕ]用作对照。与M(无)、M(IFNγ)、M(IL-4)和M(IL-10)相比，M(LPS + IC)中GAS5 RNA水平降低。使用慢病毒载体转导GAS5基因的M(LPS + IC)不表达CCL1和LIGHT mRNA（M2b Mϕ的典型生物标志物）。M(LPS + IC)中GAS5 RNA的减少是由无义介导的RNA降解（NMD）途径的激活介导的。GAS5基因转导后过表达GAS5 RNA的BMDMϕ即使联合用LPS和IC刺激也不会极化为M2b Mϕ。这些结果表明，受NMD途径激活影响的GAS5 RNA减少导致联合用LPS和IC刺激的Mϕ极化。
