Antisense Noncoding RNA in the INK4 Locus (ANRIL) is the prime candidate gene at Chr9p21, the welldefined genetic risk locus associated with multiple human diseases including coronary artery disease (CAD), while little is known regarding its role in the pathological processes. Endothelial dysfunction triggers atherosclerotic processes that are causatively linked to CAD. To evaluate the function of ANRIL in human endothelial cells (ECs), we examined ANRIL expression under pathological stimuli and found ANRIL was markedly induced by pro-inflammatory factors. Loss-of-function and chromatin immunoprecipitation approaches revealed that NF-kB mediates TNF-a induced ANRIL expression. RNA sequencing revealed that ANRIL silencing dysregulated expression of inflammatory genes including IL6 and IL8 under TNF-a treatment. We explored the regulatory mechanism of ANRIL on IL6/8 and found that Yin Yang 1 (YY1), an ANRIL binding transcriptional factor revealed by RNA immunoprecipitation, was required for IL6/8 expression under TNF-a treatment. YY1 was enriched at promoter loci of IL6/8 and ANRIL silencing impaired the enrichment, indicating a cooperation between ANRIL and YY1 in the regulation of inflammatory genes. For the first time, we establish the connection between ANRIL and NF-kB pathway and show that ANRIL regulates inflammatory responses through binding with YY1. The newly identified TNF-a-NF-kB-ANRIL/YY1-IL6/8 pathway enhances understanding of the etiology of CAD and provides potential therapeutic target for treatment of CAD.

The RPA complex can integrate multiple stress signals into diverse responses by activating distinct DNA repair pathways. However, it remains unclear how RPA1 elects to activate a specific repair pathway during different types of DNA damage. Here, we report that PCAF/GCN5-mediated K163 acetylation of RPA1 is crucial for nucleotide excision repair (NER) but is dispensable for other DNA repair pathways. Mechanistically, we demonstrate that the acetylation of RPA1 is critical for the steady accumulation of XPA at damaged DNA sites and preferentially activates the NER pathway. DNA-PK phosphorylates and activates PCAF upon UV damage and consequently promotes the acetylation of RPA1. Moreover, the acetylation of RPA1 is tightly regulated by HDAC6 and SIRT1. Together, our results demonstrate that the K163 acetylation of RPA1 plays a key role in the repair of UV-induced DNA damage and reveal how the specific RPA1 modification modulates the choice of distinct DNA repair pathways.

Heart failure (HF) is associated with mitochondrial dysfunction and energy metabolism impairment. MicroRNAs are implicated in the development of heart failure. However, the mitochondria enriched microRNA during heart failure remains elusive. Here, we generated a pressure overload-induced early and late stage heart failure model at 4 weeks and 8 weeks following transverse aortic constriction (TAC) in mice. We found that expression of mitochondrion protein COX4 was highly enriched in isolated mitochondria from cardiac tissues while GAPDH could hardly be detected. Furthermore, small RNA sequencing for mitochondria RNAs from failing hearts was performed. It was found that 69 microRNAs were upregulated and 2 were downregulated in early heart failure, while 16 microRNAs were upregulated and 6 were downregulated in late heart failure. 15 microRNA candidates were measured in both mitochondria and total cardiac tissues of heart failure by real-time PCR. MiR-696, miR-532, miR-690, and miR-345-3p were enriched in mitochondria from the failing heart at early stage. Bioinformatics analysis showed that mitochondria enriched microRNAs in HF were associated with energy metabolism and oxidative stress pathway. For the first time, we demonstrated microRNAs were enriched in mitochondria during heart failure, which established a link between microRNA and mitochondrion in heart failure.

Highlights d C1QBP stabilizes the MRE11 protein by forming the MRC complex with MRE11/RAD50 d C1QBP inhibits MRE11 exonuclease activity by preventing its binding to DNA d Appropriate C1QBP levels are essential for genomic stability and DNA repair

Aberrant programmed cell death protein 1 (PD-1) expression on the surface of T cells is known to inhibit T cell effector activity and to play a pivotal role in tumor immune escape; thus, maintaining an appropriate level of PD-1 expression is of great significance. We identified KLHL22, an adaptor of the Cul3-based E3 ligase, as a major PD-1–associated protein that mediates the degradation of PD-1 before its transport to the cell surface. KLHL22 deficiency leads to overaccumulation of PD-1, which represses the antitumor response of T cells and promotes tumor progression. Importantly, KLHL22 was markedly decreased in tumor-infiltrating T cells from colorectal cancer patients. Meanwhile, treatment with 5-fluorouracil (5-FU) could increase PD-1 expression by inhibiting the transcription of KLHL22. These findings reveal that KLHL22 plays a crucial role in preventing excessive T cell suppression by maintaining PD-1 expression homeostasis and suggest the therapeutic potential of 5-FU in combination with anti–PD-1 in colorectal cancer patients.