Molecular mechanism of human ISG20L2 for the ITS1 cleavage in the processing of 18S precursor ribosomal RNA.

The exonuclease ISG20L2 has been initially characterized for its role in the mammalian 5.8S rRNA 3' end maturation, specifically in the cleavage of ITS2 of 12S precursor ribosomal RNA (pre-rRNA). Here, we show that human ISG20L2 is also involved in 18S pre-rRNA maturation through removing the ITS1 region, and contributes to ribosomal biogenesis and cell proliferation. Furthermore, we determined the crystal structure of the ISG20L2 nuclease domain at 2.9 Å resolution. It exhibits the typical αßα fold of the DEDD 3'-5' exonuclease with a catalytic pocket located in the hollow near the center. The catalytic residues Asp183, Glu185, Asp267, His322 and Asp327 constitute the DEDDh motif in ISG20L2. The active pocket represents conformational flexibility in the absence of an RNA substrate. Using structural superposition and mutagenesis assay, we mapped RNA substrate binding residues in ISG20L2. Finally, cellular assays revealed that ISG20L2 is aberrantly up-regulated in colon adenocarcinoma and promotes colon cancer cell proliferation through regulating ribosome biogenesis. Together, these results reveal that ISG20L2 is a new enzymatic member for 18S pre-rRNA maturation, provide insights into the mechanism of ISG20L2 underlying pre-rRNA processing, and suggest that ISG20L2 is a potential therapeutic target for colon adenocarcinoma.

Rosmarinic Acid Protects Mice from Concanavalin A-Induced Hepatic Injury through AMPK Signaling.

Rosmarinic acid (RA) is extensively utilized in herbal medicine in China. The AMP-activated protein kinase (AMPK) signaling can be activated by RA and inhibited by the synthetic, reversible AMP-competitive inhibitor, Compound C (CC). The objective of this study was to investigate the role of AMPK signaling involving the protective effects of RA on concanavalin A (Con A)-induced autoimmune hepatitis (AIH) in mice. BALB/c mice were treated with RA, with or without CC, followed by the pretreatment with Con A. Analysis of serum aminotransferases and cytokines were conducted and liver tissue histology was performed to evaluate hepatic injury. Cytokine levels in serum and hepatic tissue were respectively measured by enzyme-linked immunoassay (ELISA) and used quantitative (q)PCR. Levels of phosphorylated acetyl CoA carboxylase in the liver, representing AMPK activation, were detected by Western blotting. Compared with the Con A group, serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in RA group (100 and 150 mg/kg/d) were significantly reduced. RA also reduced hepatocyte swelling, cell death, and infiltration of leukocytes in the liver of Con A-treated mice. Serum levels of cytokines, such as interferon-γ (IFN-γ), interleukin-2 (IL-2) and interleukin-1ß (IL-1ß), were reduced by RA pretreatment, while the levels of serum interleukin-10 (IL-10), an anti-inflammatory cytokine, was elevated. These protective effects were reversed by treatment with CC. RA treatment reduced the hepatic damage via the activation of AMPK in the mice of Con A-induced. So RA acts as a potential part in the therapy of autoimmune hepatitis.

Pelvic Abscess Caused by Ureteral Calculus and Abscess Treatment through Aspiration by Transperineal Puncture.

Pelvic abscess is mostly caused by gynecological inflammation or digestive system diseases such as appendicitis or Crohn's disease. This case of pelvic abscess originates from ureteral calculus and is not commonly seen in clinical practice. This is mainly due to the patient's ureteral stones not being actively treated. After local puncture and pus extraction, as well as the application of effective antibiotics, the patient recovered. Therefore, this case provides clinical doctors with experience that ureteral stones may cause serious complications and should be actively treated after detection.