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Peroxisome import stress impairs ribosome biogenesis and induces integrative stress response through eIF2α phosphorylation
bioRxiv - Genomics Pub Date : 2021-01-13 , DOI: 10.1101/2020.11.19.390609
Kerui Huang , Jinoh Kim , Pham Vo , Ting Miao , Hua Bai

Peroxisome biogenesis diseases (PBDs) are characterized by global defects in peroxisomal function and can result in severe brain, liver, kidney, and bone malfunctions. PBDs are due to mutations in peroxisome biogenesis factors (PEX genes) that are responsible for peroxisome assembly and function. Increasing evidence suggests that peroxisome import functions decline during aging. However, the transcriptome profiling of peroxisome import defects and how they affect disease development are still lacking. PEX5 encodes the cytoplasmic receptors for peroxisome-targeting signal types 1. We generate knock-in human HEK293 cells mutant using CRISPR to transiently express PEX5 cysteine 11 to alanine mutant (PEX5C11A), which blocks PEX5 recycling and exerts dominant negative effect on PEX5 mediated peroxisome import. To identify conserved responses, we perform transcriptomic analysis on Drosophila oenocyte-specific Pex1, Pex12 and Pex5 knockdowns and on human cells with impaired peroxisome import (PEX5C11A and PEX5 siRNA respectively). PEX5C11A induction triggers vast transcriptomic changes, including decreased oxidative phosphorylation, increased MAPK signaling and HIPPO signaling. PEX5 siRNA specifically decreases spliceosome activity and increases cholesterol metabolism. Using gene set enrichment analysis (GSEA), we identify protein processing in endoplasmic reticulum pathway, specifically ER-associated protein degradation (ERAD) pathway is induced in all PEX knockdowns in Drosophila. Peroxisome dysfunction elevates eIF2α phosphorylation in both Drosophila and human cell culture independent of XBP1 activation, suggesting increased integrative stress response (ISR). Moreover, peroxisome stress decreases ribosome biogenesis genes and impairs ribosome biogenesis in flies and human cells. Specifically, peroxisome stress impairs the 5'-ETS cleavage activity during the ribosome biogenesis and dampens 40S small ribosomal export in both flies and human. Our results suggest that reduced ribosome biogenesis and elevated ISR could be conserved cellular response to peroxisome import stress.

中文翻译:

过氧化物酶体输入应激会破坏核糖体的生物发生并通过eIF2α磷酸化诱导整合应激反应

过氧化物酶体生物发生疾病(PBD)的特征是过氧化物酶体功能的整体缺陷,并可能导致严重的脑,肝,肾和骨骼功能异常。PBD是由于负责过氧化物酶体装配和功能的过氧化物酶体生物发生因子(PEX基因)中的突变引起的。越来越多的证据表明过氧化物酶体的导入功能在衰老过程中会下降。然而,仍然缺乏过氧化物酶体导入缺陷的转录组分析以及它们如何影响疾病发展。PEX5编码针对过氧化物酶体靶向信号类型1的胞质受体。我们使用CRISPR生成敲入的人类HEK293细胞突变体,以将PEX5半胱氨酸11瞬时表达为丙氨酸突变体(PEX5C11A),这会阻止PEX5循环并对PEX5介导的过氧化物酶体起主要的负面作用进口。为了确定保守的回应,我们对果蝇卵母细胞特异性Pex1,Pex12和Pex5敲低以及过氧化物酶体导入受损的人细胞(分别为PEX5C11A和PEX5 siRNA)进行转录组分析。PEX5C11A诱导触发大量转录组变化,包括减少的氧化磷酸化,增加的MAPK信号传导和HIPPO信号传导。PEX5 siRNA特异性降低剪接体活性并增加胆固醇代谢。使用基因集富集分析(GSEA),我们确定了内质网途径中的蛋白质加工,特别是果蝇中所有PEX敲低中都诱导了ER相关蛋白降解(ERAD)途径。过氧化物酶体功能障碍可提高果蝇和人类细胞培养物中eIF2α的磷酸化,而不受XBP1激活的影响,表明整合应激反应(ISR)增加。此外,过氧化物酶体胁迫减少果蝇和人类细胞中核糖体的生物发生基因并损害核糖体的生物发生。具体而言,过氧化物酶体应激会损害核糖体生物发生过程中的5'-ETS裂解活性,并抑制果蝇和人的40S小核糖体输出。我们的结果表明,减少核糖体的生物发生和提高ISR可以保持细胞对过氧化物酶体输入应激的反应。
更新日期:2021-01-14
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