■克罗恩病(CD)是一种慢性炎症性肠病,其病因涉及遗传,环境和微生物因素。粘附侵袭性大肠杆菌(AIEC)和自噬相关基因的多态性与CD病因学有关。自噬是维持细胞稳态的关键过程,这允许通过溶酶体降解受损的细胞质成分和病原体。我们已经表明,功能性自噬对于AIEC清除是必需的。这里,我们旨在鉴定负责将AIEC靶向自噬降解的自噬受体。
■使用siRNA在人肠上皮细胞T84中下调自噬受体p62,NDP52,NBR1,TAX1BP1和Optineurin的水平。NDP52敲除(KO)和p62KOHeLa细胞,使用表达野生型NDP52或突变的NDP52Val248Ala蛋白的NDP52KOHeLa细胞。
■我们证明了,在测试的自噬受体(p62,NDP52,NBR1,TAX1BP1和视神经磷酸酶)中,p62或NDP52的表达减少增加了上皮细胞内临床AIECLF82菌株的数量。这与促炎细胞因子产生增加有关。此外,p62或NDP52与AIECLF82和自噬标记物LC3直接共定位。由于NDP52Val248Ala多态性与CD易感性增加相关,我们调查了它对AIEC控制的影响。然而,在HeLa细胞中,在我们的实验条件下,没有观察到这种多态性对AIECLF82细胞内数量和促炎细胞因子产生的影响。一起,我们的结果表明,p62和NDP52作为AIEC识别的自噬受体,控制AIEC细胞内复制和炎症。
UNASSIGNED: Crohn\'s disease (CD) is a chronic inflammatory bowel disease, of which the etiology involves genetic, environmental and microbial factors. Adherent-invasive Escherichia coli (AIEC) and polymorphisms in autophagy-related genes have been implicated in CD etiology. Autophagy is a key process for the maintenance of cellular homeostasis, which allows the degradation of damaged cytoplasmic components and pathogens via lysosome. We have shown that a functional autophagy is necessary for AIEC clearance. Here, we aimed at identifying the autophagy receptor(s) responsible to target AIEC to autophagy for degradation.
UNASSIGNED: The levels of autophagy receptors p62,
NDP52, NBR1, TAX1BP1 and Optineurin were knocked down in human intestinal epithelial cells T84 using siRNAs. The
NDP52 knock-out (KO) and p62 KO HeLa cells, as well as
NDP52 KO HeLa cells expressing the wild-type
NDP52 or the mutated NDP52Val248Ala protein were used.
UNASSIGNED: We showed that, among the tested autophagy receptors (p62,
NDP52, NBR1, TAX1BP1 and Optineurin), diminished expression of p62 or NDP52 increased the number of the clinical AIEC LF82 strain inside epithelial cells. This was associated with increased pro-inflammatory cytokine production. Moreover, p62 or
NDP52 directly colocalized with AIEC LF82 and LC3, an autophagy marker. As the NDP52Val248Ala polymorphism has been associated with increased CD susceptibility, we investigated its impact on AIEC control. However, in HeLa cell and under our experimental condition, no effect of this polymorphism neither on AIEC LF82 intracellular number nor on pro-inflammatory cytokine production was observed. Together, our results suggest that p62 and NDP52 act as autophagy receptors for AIEC recognition, controlling AIEC intracellular replication and inflammation.