Epigenetic Dysregulation Induces Translocation of Histone H3 into Cytoplasm

• Published in: Advanced science 2021-10, Vol.8 (19), p.e2100779-n/a
• Main Authors: Wang, Zhen, Chen, Ji, Gao, Chuan, Xiao, Qiong, Wang, Xi‐Wei, Tang, Shan‐Bo, Li, Qing‐Lan, Zhong, Bo, Song, Zhi‐Yin, Shu, Hong‐Bing, Li, Lian‐Yun, Wu, Min
• Format: Article
• Language: English
• Subjects: Animals; Antibodies; Apoptosis; Autoimmune diseases; Autophagy; Cancer; cGAS; Cytoplasm; Cytoplasm - genetics; Cytoplasm - metabolism; Diabetic retinopathy; DNA methylation; Enzymes; Epigenesis, Genetic - genetics; Epigenetics; Gene expression; Genotype & phenotype; H3K9me3; heterochromatin; Histones - genetics; Histones - metabolism; HP1α; Localization; Male; Mice; Mice, Inbred BALB C; Microscopy; Mitochondria; Models, Animal; Proteins; SETDB1; Transcription Factors - genetics
• ISSN: 2198-3844; 2198-3844
• DOI: 10.1002/advs.202100779

In eukaryote cells, core components of chromatin, such as histones and DNA, are packaged in nucleus. Leakage of nuclear materials into cytosol will induce pathological effects. However, the underlying mechanisms remain elusive. Here, cytoplasmic localization of nuclear materials induced by chromatin dysregulation (CLIC) in mammalian cells is reported. H3K9me3 inhibition by small chemicals, HP1α knockdown, or knockout of H3K9 methylase SETDB1, induces formation of cytoplasmic puncta containing histones H3.1, H4 and cytosolic DNA, which in turn activates inflammatory genes and autophagic degradation. Autophagy deficiency rescues H3 degradation, and enhances the activation of inflammatory genes. MRE11, a subunit of MRN complex, enters cytoplasm after heterochromatin dysregulation. Deficiency of MRE11 or NBS1, but not RAD50, inhibits CLIC puncta in cytosol. MRE11 depletion represses tumor growth enhanced by HP1α deficiency, suggesting a connection between CLIC and tumorigenesis. This study reveals a novel pathway that heterochromatin dysregulation induces translocation of nuclear materials into cytoplasm, which is important for inflammatory diseases and cancer. The current study reveals a novel pathway leading to cytoplasmic localization of nuclear material induced by chromatin dysregulation (CLIC). HP1α knockdown, SETDB1 knockout or H3K9me3 inhibition by drugs, induces cytoplasmic puncta containing histones H3.1, H4 and DNA, which is regulated by MRE11 and NBS1. CLIC activates inflammatory gene expression, γH2AX formation, and autophagy, and is related with inflammation and tumorigenesis.