YAF2 exerts anti-apoptotic effect in human tumor cells in a FANK1- and phosphorylation-dependent manner

Tubular IKKβ Deletion Alleviates Acute Ischemic Kidney Injury and Facilitates Tissue Regeneration

Acute kidney injury (AKI) is a common renal injury leading to relevant morbidity and mortality worldwide. Most of the clinical cases of AKI are caused by ischemia reperfusion (I/R) injury with renal ischemia injury followed by reperfusion injury and activation of the innate immune response converging to NF-ĸB pathway induction. Despite the clear role of NF-ĸB in inflammation, it has recently been acknowledged that NF-ĸB may impact other cell functions. To identify NF-ĸB function with respect to metabolism, vascular function and oxidative stress after I/R injury and to decipher in detail the underlying mechanism, we generated a transgenic mouse model with targeted deletion of IKKβ along the tubule and applied I/R injury followed by its analysis after 2 and 14 days after I/R injury. Tubular IKKβ deletion ameliorated renal function and reduced tissue damage. RNAseq data together with immunohistochemical, biochemical and morphometric analysis demonstrated an ameliorated vascular organization and mRNA expression profile for increased angiogenesis in mice with tubular IKKβ deletion at 2 days after I/R injury. RNAseq and protein analysis indicate an ameliorated metabolism, oxidative species handling and timely-adapted cell proliferation and apoptosis as well as reduced fibrosis in mice with tubular IKKβ deletion at 14 days after I/R injury. In conclusion, mice with tubular IKKβ deletion upon I/R injury display improved renal function and reduced tissue damage and fibrosis in association with improved vascularization, metabolism, reactive species disposal and fine-tuned cell proliferation.

Critical Roles of Polycomb Repressive Complexes in Transcription and Cancer

Polycomp group (PcG) proteins are members of highly conserved multiprotein complexes, recognized as gene transcriptional repressors during development and shown to play a role in various physiological and pathological processes. PcG proteins consist of two Polycomb repressive complexes (PRCs) with different enzymatic activities: Polycomb repressive complexes 1 (PRC1), a ubiquitin ligase, and Polycomb repressive complexes 2 (PRC2), a histone methyltransferase. Traditionally, PRCs have been described to be associated with transcriptional repression of homeotic genes, as well as gene transcription activating effects. Particularly in cancer, PRCs have been found to misregulate gene expression, not only depending on the function of the whole PRCs, but also through their separate subunits. In this review, we focused especially on the recent findings in the transcriptional regulation of PRCs, the oncogenic and tumor-suppressive roles of PcG proteins, and the research progress of inhibitors targeting PRCs.

Salidroside alleviates severe acute pancreatitis-triggered pancreatic injury and inflammation by regulating miR-217-5p/YAF2 axis

BACKGROUND

Our previous studies have shown that salidroside (Sal) exerted a protective effect in severe acute pancreatitis (SAP) via inhibiting the inflammatory response. However, the molecular mechanism has not been fully elucidated.

METHODS

Using SAP rat model and miRNA microarray, the effect of Sal on miRNA expression profiling was determined and then validated their changes by quantitative Real-time PCR (qRT-PCR). Then, SAP cell model, enzyme-linked immunosorbent assay (ELISA) and Cell Counting Kit-8 (CCK-8) assay were used to explore the biological function of miR-217-5p in vitro. Bioinformatics analysis, luciferase reporter assay and miRNA pulldown assay were performed to investigate the underlying mechanism of miR-217-5p in the protection of Sal against SAP.

RESULTS

Compared with SAP group, 21 differentially expressed miRNAs were identified in SAP + Sal group. The target genes of these miRNAs were strongly associated with regulation of transcription, Axon guidance, Pathways in cancer and MAPK signaling pathway. Among these miRNAs, miR-217-5p was the most downregulated miRNA. Sal treatment alleviated cell injury and reduced the production of pro-inflammatory cytokines. Whereas overexpression of miR-217-5p reversed the effects of Sal. We identified YY1 associated factor 2 (YAF2) as a direct target gene of miR-217-5p and Sal treatment could upregulate YAF2 expression via targeting miR-217-5p. Furthermore, knockdown of YAF2 counteracted Sal-induced alleviation of cell injury and inflammation. Moreover, Sal could suppress the activation of p38 MAPK pathway by regulating miR-217-5p/YAF2 axis.

CONCLUSIONS

Our findings for the first time highlighted that Sal alleviated pancreatic injury and inhibited inflammation by regulating miR-217-5p/YAF2 axis, which might provide new therapeutic strategies for SAP treatment.

Mechanisms of Polycomb group protein function in cancer

Cancer arises from a multitude of disorders resulting in loss of differentiation and a stem cell-like phenotype characterized by uncontrolled growth. Polycomb Group (PcG) proteins are members of multiprotein complexes that are highly conserved throughout evolution. Historically, they have been described as essential for maintaining epigenetic cellular memory by locking homeotic genes in a transcriptionally repressed state. What was initially thought to be a function restricted to a few target genes, subsequently turned out to be of much broader relevance, since the main role of PcG complexes is to ensure a dynamically choregraphed spatio-temporal regulation of their numerous target genes during development. Their ability to modify chromatin landscapes and refine the expression of master genes controlling major switches in cellular decisions under physiological conditions is often misregulated in tumors. Surprisingly, their functional implication in the initiation and progression of cancer may be either dependent on Polycomb complexes, or specific for a subunit that acts independently of other PcG members. In this review, we describe how misregulated Polycomb proteins play a pleiotropic role in cancer by altering a broad spectrum of biological processes such as the proliferation-differentiation balance, metabolism and the immune response, all of which are crucial in tumor progression. We also illustrate how interfering with PcG functions can provide a powerful strategy to counter tumor progression.