a Department of Molecular Cell Biology and Samsung Biomedical Research Institute , Sungkyunkwan University School of Medicine , Suwon , Republic of Korea.
b Department of Immunology and Infectious Diseases, Harvard School of Public Health, and the Department of Medicine , Harvard Medical School , Boston , MA , USA.
Autophagy. 2018;14(8):1347-1358. doi: 10.1080/15548627.2018.1474995. Epub 2018 Jul 23.
TRAF6 (TNF receptor associated factor 6) plays a pivotal role in NFKB activation and macroautphagy/autophagy activation induced by TLR4 (toll like receptor 4) signaling. The objective of this study was to determine the functional role of PRDX1 (peroxiredoxin 1) in NFKB activation and autophagy activation. PRDX1 interacted with the ring finger domain of TRAF6 and inhibited its ubiquitin-ligase activity. The inhibition on TRAF6 ubiquitin-ligase activity by PRDX1 induced the suppression of ubiquitination of an evolutionarily conserved signaling intermediate in Toll pathways (ECSIT) essential for NFKB activation and BECN1 (beclin 1) required for autophagy activation. An inhibitory effect of PRDX1 on TRAF6 was clearly evidenced in PRDX1-knockdown (PRDX1KD) THP-1, PRDX1KD MDA-MB-231, and PRDX1KD SK-HEP-1 cells. PRDX1KD THP-1 cells showed increases of NFKB activation, pro-inflammatory cytokine production, NFKB-dependent gene expression induced by TLR4 stimulation, and resistance against Salmonella typhimurium infection. Additionally, migration and invasion abilities of PRDX1KD MDA-MB-231 and PRDX1KD SK-HEP-1 cancer cells were significantly enhanced compared to those of control cancer cells. Taken together, these results suggest that PRDX1 negatively regulates TLR4 signaling for NFKB activation and autophagy functions such as bactericidal activity, cancer cell migration, and cancer cell invasion by inhibiting TRAF6 ubiquitin-ligase activity.
3-MA: 3-methyladenine; BECN1: beclin 1; CHUK/IKKA: conserved helix-loop-helix ubiquitous kinase; ECSIT: ECSIT signalling integrator; ELISA: enzyme-linked immunosorbent assay; NFKB: nuclear factor kappa-light-chain-enhancer of activated B cells; IB: immunoblotting; IKBKB/IKKB: inhibitor of nuclear factor kappa B kinase subunit beta; IL1B: interleukin 1 beta; IL6: interleukin 6; IP: immunoprecipitation; LPS: lipopolysaccharide; MAP1LC3/LC3: microtuble associated protein 1 light chain 3; MAP3K7/TAK1: mitogen-activated protein kinase kinase kinase 7; MAPK14/p38: mitogen-activated protein kinase 14; mROS: mitochondrial reactive oxygen species; PRDX1: peroxiredoxin 1; PRDX6: peroxiredoxin 6; RELA/p65: RELA proto-oncogene, NF-kB subunit; TRAF6 TNF: receptor associated factor 6.
确定 PRDX1（过氧化物还原酶 1）在 NFKB 激活和自噬激活中的功能作用。方法：PRDX1 与 TRAF6 的环指结构域相互作用，并抑制其泛素连接酶活性。PRDX1 对 TRAF6 泛素连接酶活性的抑制作用诱导了 Toll 途径中进化上保守的信号中间体（ECSIT）的泛素化抑制，该中间体对于 NFKB 激活和自噬激活所必需的 BECN1（beclin 1）至关重要。PRDX1 对 TRAF6 的抑制作用在 PRDX1 敲低（PRDX1KD）THP-1、PRDX1KD MDA-MB-231 和 PRDX1KD SK-HEP-1 细胞中得到了明确的证据。PRDX1KD THP-1 细胞显示 NFKB 激活、促炎细胞因子产生、TLR4 刺激诱导的 NFKB 依赖性基因表达以及沙门氏菌感染抗性增加。此外，PRDX1KD MDA-MB-231 和 PRDX1KD SK-HEP-1 癌细胞的迁移和侵袭能力与对照癌细胞相比显著增强。结论：PRDX1 通过抑制 TRAF6 泛素连接酶活性，负调控 TLR4 信号转导，从而抑制 NFKB 激活和自噬功能，如杀菌活性、癌细胞迁移和癌细胞侵袭。缩写：3-MA：3-甲基腺嘌呤；BECN1：beclin 1；CHUK/IKKA：保守螺旋-环-螺旋泛素激酶；ECSIT：ECSIT 信号整合器；ELISA：酶联免疫吸附测定；NFKB：核因子 kappa-轻链增强子的 B 细胞；IB：免疫印迹；IKBKB/IKKB：核因子 kappa B 激酶亚单位β抑制剂；IL1B：白细胞介素 1β；IL6：白细胞介素 6；IP：免疫沉淀；LPS：脂多糖；MAP1LC3/LC3：微管相关蛋白 1 轻链 3；MAP3K7/TAK1：丝裂原活化蛋白激酶激酶激酶 7；MAPK14/p38：丝裂原活化蛋白激酶 14；mROS：线粒体活性氧；PRDX1：过氧化物还原酶 1；PRDX6：过氧化物还原酶 6；RELA/p65：RELA 原癌基因，NF-kB 亚单位；TRAF6 TNF：肿瘤坏死因子受体相关因子 6。
