Inducible expression of heat shock protein 20 protects airway epithelial cells against oxidative injury involving the Nrf2-NQO-1 pathway.
Inducible expression of heat shock protein 20 protects airway epithelial cells against oxidative injury involving the Nrf2-NQO-1 pathway.
复制标题
热休克蛋白 20 的诱导表达可保护气道上皮细胞免受涉及 Nrf2-NQO-1 通路的氧化损伤。
DOI：
10.1186/s13578-020-00483-3
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发表时间：
2020
影响因子：
7.5
通讯作者：
Zhang M
中科院分区：
文献类型：
--
作者：
Bao A;Ma A;Zhang H;Qiao L;Ben S;Zhou X;Zhang M
热休克蛋白（HSP）20 是一种分子伴侣，在多种组织中发挥多种保护功能。然而，HSP20 在气道上皮细胞（AECs）中的表达情况及其具体功能仍不明确。
在本研究中，我们首先证实了在不同氧化应激源作用下，小鼠 AECs 及人支气管上皮细胞系 BEAS - 2B 细胞中 HSP20 的诱导性表达。随后，通过反复低水平臭氧暴露建立 HSP20 高表达小鼠模型，并以单次高水平臭氧暴露刺激该模型，我们发现，HSP20 含量增加及其磷酸化增强可能有助于减轻氧化损伤，这表现为体重减轻程度降低、支气管肺泡灌洗液（BAL）中中性粒细胞积聚减少、AECs 脱落减少以及 BAL 中白蛋白和 E - 钙黏蛋白浓度降低。在 BEAS - 2B 细胞中进一步研究了 HSP20 的生物学功能及其分子机制。在以过氧化氢（H₂O₂）刺激细胞前，将 HSP20 质粒、不可磷酸化的 HSP20（Ala）质粒或空载体质粒转染至 BEAS - 2B 细胞，已证实 H₂O₂ 在气液培养系统中的氧化能力与臭氧相似。我们发现，在转染 HSP20 质粒而非 HSP20（Ala）质粒的细胞中，H₂O₂ 诱导的细胞内活性氧（ROS）水平及早期细胞凋亡均有所减弱。在 H₂O₂ 刺激后，转染 HSP20 质粒的细胞中醌氧化还原酶 - 1（NQO - 1，mRNA 和蛋白）的细胞内表达及核内 Nrf2 含量显著增加，而转染 HSP20（Ala）质粒和空载体质粒的细胞则无此现象。
氧化应激诱导 AECs 中 HSP20 表达，对氧化损伤发挥保护作用，这可能涉及 Nrf2 - NQO - 1 通路的激活。
Heat shock protein (HSP) 20 is a molecular chaperone that exerts multiple protective functions in various kinds of tissues. However, the expression of HSP20 and its specific functions in airway epithelial cells (AECs) remain elusive. In current study, we first confirmed the inducible expression of HSP20 in mouse AECs and in a human bronchial epithelial cell line BEAS-2B cells, under different oxidant stressors. Then by establishing a HSP20-abundant mouse model with repeated low-level-ozone exposures and stimulating this model with a single high-level ozone exposure, we found that the HSP20 abundance along with its enhanced phosphorylation potentially contributed to the alleviation of oxidative injuries, evidenced by the decreases in the bodyweight reduction, the BAL neutrophil accumulation, the AECs shedding, and the BAL concentrations of albumin and E-cadherin. The biological function of HSP20 and its molecular mechanisms were further investigated in BEAS-2B cells that were transfected with HSP20-, unphosphorylatable HSP20(Ala) or empty vector plasmids prior to the stimulation of H2O2, of which its oxidant capacity has been proved to be similar with those of ozone in an air–liquid culture system. We found that the H2O2-induced intracellular ROS level and the early cell apoptosis were attenuated in the HSP20- but not HSP20(Ala)- transfected cells. The intracellular expression of NQO-1 (mRNA and protein) and the intranuclear content of Nrf2 were significantly increased in the HSP20- transfected cells but not in the HSP20(Ala)- and empty vector-transfected cells after the stimulation of H2O2. The inducible expression of HSP20 in AECs by oxidative stress exerts protective roles against oxidative damages, which may involve the activation of the Nrf2-NQO-1 pathway.