Tissue kallikrein protects SH-SY5Y neuronal cells against oxygen and glucose deprivation-induced injury through bradykinin B2 receptor-dependent regulation of autophagy induction
Tissue kallikrein protects SH-SY5Y neuronal cells against oxygen and glucose deprivation-induced injury through bradykinin B2 receptor-dependent regulation of autophagy induction
复制标题
组织激肽释放酶通过缓激肽 B2 受体依赖性自噬诱导调节，保护 SH-SY5Y 神经元细胞免受缺氧和缺糖引起的损伤。
DOI：
10.1111/jnc.13690
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发表时间：
2016-10-01
影响因子：
4.7
通讯作者：
Dong, Qiang
中科院分区：
文献类型：
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作者：
Liu, Yanping;Lu, Zhengyu;Dong, Qiang
已有研究表明，组织激肽肽（TK）主要通过缓激肽B2受体（B2R）抑制细胞凋亡来保护脑缺血损伤。本研究提出自噬诱导参与了TK的神经保护机制。为了验证这一假设，我们研究了暴露于氧和葡萄糖剥夺（OGD）的人SH-SY5Y细胞中tk诱导的自噬及其信号传导机制。我们发现TK处理增强了自噬诱导，体现在LC3转化和Beclin1表达增强，p62水平降低，单体红色荧光蛋白LC3斑点形成增加。绿色荧光蛋白-单体红色荧光蛋白- lc3腺病毒检测表明TK保持了自噬通量。此外，巴菲霉素A1 (Baf。A1)在TK存在或不存在的情况下均引起明显的LC3-II积累。Beclin1敲低或Baf抑制自噬。A1治疗消除了TK的神经保护作用。丝裂原活化蛋白激酶激酶1/2 (MEK1/2)/细胞外信号调节激酶（ERK） 1/2和amp活化蛋白激酶(AMPK)/结节硬化复合体2 (TSC2)/哺乳动物雷帕霉素靶点（mTOR）信号在OGD胁迫下被诱导，TK增强。MEK/ERK抑制剂U0126单独升高OGD条件下的自噬，但损害tk诱导的自噬。AMPK抑制剂化合物C和shRNA阻断AMPK/TSC2/mTOR信号通路介导AMPK α 1和TSC2的下调，但在有TK或不含TK的OGD处理的SH-SY5Y细胞中，自噬被抑制。此外，暴露于OGD后，B2R的表达上调。无论TK是否存在，B2R敲低都能减弱OGD条件下的自噬，抑制MEK1/2/ERK1/2和AMPK/TSC2/mTOR信号。综上所述，我们揭示了b2r介导的MEK/ERK和AMPK信号在OGD胁迫下诱导自噬中的重要作用，并通过b2r依赖性的自噬调控提出了参与TK神经保护功能的新机制。
Previous studies have demonstrated that tissue kallikrein (TK) protects against cerebral ischemia injury mainly through inhibition of apoptosis via bradykinin B2 receptor (B2R). In this study, we proposed that autophagy induction contributed to the neuroprotective mechanism of TK. To validate this hypothesis, we investigated TK-induced autophagy and its signaling mechanisms in human SH-SY5Y cells exposed to oxygen and glucose deprivation (OGD). We found that TK treatment enhanced autophagy induction, reflected by augmented LC3 conversion and Beclin1 expression, decreased p62 levels and increased monomeric red fluorescent proteinLC3 puncta formation. Green fluorescent protein-monomeric red fluorescent protein-LC3 adenovirus assay indicated that TK maintained autophagic flux. Moreover, bafilomycin A1 (Baf. A1) caused obvious LC3-II accumulation either in the presence or absence of TK. Autophagy inhibition by Beclin1 knockdown or Baf. A1 treatment abrogated the neuroprotective effects of TK. Mitogen-activated protein kinase kinase 1/2 (MEK1/2)/extracellular signal-regulated kinase (ERK) 1/2 and AMP-activated protein kinase (AMPK)/tuberous sclerosis complex 2 (TSC2)/mammalian target of rapamycin (mTOR) signaling were induced by OGD stress and enhanced by TK. MEK/ERK inhibitor U0126 alone elevated autophagy in OGD conditions, but impaired TK-induced autophagy. Blockade of AMPK/TSC2/mTOR signaling by AMPK inhibitor compound C and shRNA mediated the knockdown of AMPK alpha 1 and TSC2 but abolished autophagy in SH-SY5Y cells exposed to OGD treated either with or without TK. Moreover, B2R expression was up-regulated by OGD exposure. B2R knockdown attenuated autophagy and suppressed MEK1/2/ERK1/2 and AMPK/TSC2/mTOR signaling in OGD conditions in either the presence or absence of TK. In sum, we revealed the significance of B2R-mediated MEK/ERK and AMPK signaling in autophagy induction under OGD stress, and proposed novel mechanisms involved in the neuropotective function of TK through B2R-dependent regulation of autophagy.