The role and mechanism of long non-coding RNAs in homologous recombination repair of radiation-induced DNA damage

GRIK1-AS1 deficiency accelerates endometriosis progression by boosting DNMT1-dependent SFRP1 promoter methylation in endometrial stromal cells

BACKGROUND

Endometriosis, a gynecological disease that affects up to 10% of women, is a major cause of pain and infertility. Deregulation of the epigenome is accountable for the onset and progression of endometriosis, although its exact mechanism is unknown. The purpose of the current study is to examine the role of the long non-coding RNA (lncRNA) GRIK1-AS1 in the epigenetic regulation of endometrial stromal cell proliferation and the development of endometriosis.

METHODS

Endometriosis datasets were screened to identify GRIKI-AS1 as dramatically declining in endometriosis. Gain or loss of function endometrial stromal cell (ESC) models were established. The anti-proliferation phenotype was investigated using in vitro and in vivo experiments. Epigenetic regulatory network analyses were conducted to suggest the intrinsic molecular mechanism.

RESULTS

With bioinformatic and clinical data, we observed that GRIK1-AS1 and SFRP1 were expressed at low levels in endometriosis. Overexpressed GRIK1-AS1 inhibited ESC proliferation, while SFRP1 knockdown rescued the antiproliferative ability of GRIK1-AS1. Specifically, methylation-dependent expression inhibition of SFRP1 was revealed in ESCs. Mechanistically, GRIK1-AS1 hampers the occupancy of DNMT1 in SRFP1 promoter, leading to hypomethylation of SFRP1 and upregulated SFRP1 expression, thereby potentially suppressing Wnt signaling and its adverse proliferative effect. Therapeutically, lentivirus-mediated upregulation of GRIK1-AS1 inhibited endometriosis disease progression in vivo.

CONCLUSIONS

Our study is a proof-of-concept demonstration for GRIKI-AS1-associated endometriosis pathogenesis and highlights a potential intervention target.

Long noncoding RNAs contribute to DNA damage resistance in Arabidopsis thaliana

Efficient repair of DNA lesions is essential for the faithful transmission of genetic information between somatic cells and for genome integrity across generations. Plants have multiple, partially redundant, and overlapping DNA repair pathways, probably due to the less constricted germline and the inevitable exposure to light including higher energy wavelengths. Many proteins involved in DNA repair and their mode of actions are well described. In contrast, a role for DNA damage-associated RNA components, evident from many other organisms, is less well understood. Here, we have challenged young Arabidopsis thaliana plants with two different types of genotoxic stress and performed de novo assembly and transcriptome analysis. We identified three long noncoding RNAs (lncRNAs) that are lowly or not expressed under regular conditions but up-regulated or induced by DNA damage. We generated CRISPR/Cas deletion mutants and found that the absence of the lncRNAs impairs the recovery capacity of the plants from genotoxic stress. The genetic loci are highly conserved among world-wide distributed Arabidopsis accessions and within related species in the Brassicaceae group. Together, these results suggest that the lncRNAs have a conserved function in connection with DNA damage and provide a basis for mechanistic analysis of their role.