DEAD-box proteins are named after the strictly conserved sequence Asp-Glu-Ala-Asp (D-E-A-D) and widely found in organisms from bacteria to humans. They are involved in many aspects of RNA metabolism, such as transcription, pre-mRNA splicing, transport, translation, mRNA decay and ribosome biogenesis. DDX41 is a member of the DEAD-box proteins and acts as an intracellular DNA sensor in myeloid dendritic cells. On viral infection, the DDX41 will be phosphorylated by BTK kinase [Detail] ...
RNA helicases are involved in almost every aspect of RNA, from transcription to RNA decay. DExD/H-box helicases comprise the largest SF2 helicase superfamily, which are characterized by two conserved RecA-like domains. In recent years, an increasing number of unexpected functions of these proteins have been discovered. They play important roles not only in innate immune response but also in diseases like cancers and chronic hepatitis C. In this review, we summarize the recent literatures on one member of the SF2 superfamily, the DEADbox protein DDX41. After bacterial or viral infection, DNA or cyclic-di-GMP is released to cells. After phosphorylation of Tyr414 by BTK kinase, DDX41 will act as a sensor to recognize the invaders, followed by induction of type I interferons (IFN). After the immune response, DDX41 is degraded by the E3 ligase TRIM21, using Lys9 and Lys115 of DDX41 as the ubiquitination sites. Besides the roles in innate immunity, DDX41 is also related to diseases. An increasing number of both inherited and acquired mutations in DDX41 gene are identified from myelodysplastic syndrome and/or acute myeloid leukemia (MDS/AML) patients. The review focuses on DDX41, as well as its homolog Abstrakt in Drosophila, which is important for survival at all stages throughout the life cycle of the fly.
Dementia is a comprehensive category of brain diseases that is great enough to affect a person’s daily functioning. The most common type of dementia is Alzheimer’s disease, which makes most of cases. New researches indicate that gastrointestinal tract microbiota are directly linked to dementia pathogenesis through triggering metabolic diseases and low-grade inflammation progress. A novel strategy is proposed for the management of these disorders and as an adjuvant for psychiatric treatment of dementia and other related diseases through modulation of the microbiota (e.g. with the use of probiotics).
P-selectin engagement of P-selectin glycoprotein ligand-1 (PSGL-1) causes circulating leukocytes to roll on and adhere to the vascular surface, and mediates intracellular calcium flux, a key but unclear event for subsequent arresting firmly at and migrating into the infection or injured tissue. Using a parallel plate flow chamber technique and intracellular calcium ion detector (Fluo-4 AM), the intracellular calciumflux of firmly adhered neutrophils on immobilized P-selectin in the absence of chemokines at various wall shear stresseswas investigated here in real time by fluorescence microscopy. The results demonstrated that P-selectin engagement of PSGL-1 induced the intracellular calcium flux of firmly adhered neutrophils in flow, increasing P-selectin concentration enhanced cellular calcium signaling, and, force triggered, enhanced and quickened the cytoplasmic calcium bursting of neutrophils on immobilized P-selectin. This P-selectin-induced calcium signaling should come from intracellular calcium release rather than extracellular calcium influx, and be along the mechano-chemical signal pathway involving the cytoskeleton, moesin and Spleen tyrosine kinase (Syk). These results provide a novel insight into the mechano-chemical regulation mechanism for P-selectininduced calcium signaling of neutrophils in flow.
Increasing attention is focused on the down-regulation of miRNAs in cancer process. Nuclear receptor subfamily 2 (NR2F2, also known as COUP-TFII) is involved in the development of many types of cancers, but its role in gastric cancer remains elusive. In this experiment, oncomine and Kaplan-meier database revealed that NR2F2 was up-regulated in gastric cancer and that the high NR2F2 expression contributed to poor survival. MicroRNA-27b was targeted and down-regulated by NR2F2 in human gastric cancer tissues and cells. The ectopic expression of miR-27b inhibited gastric cancer cell proliferation and tumor growth in vitroand in vivo. Assays suggested that the overexpression of miR-27b could promote MGC-803 cells’ migration and invasion and retard their metastasis to the liver. In addition, down-regulation of miR-27b enhanced GES-1 cells’ proliferation and metastasis in vitro. These findings reveal that miR-27b is a tumor suppressor in gastric cancer and a biomarker for improving patients’ survival.
Human monocyte is an important cell type which is involved in various complex human diseases. To better understand the biology of human monocytes and facilitate further studies, we developed the first comprehensive proteome knowledge base specifically for human monocytes by integrating both in vivoand in vitrodatasets. The top 2000 expressed genes from in vitrodatasets and 779 genes from in vivoexperiments were integrated into this study. Altogether, a total of 2237 unique monocyte-expressed genes were cataloged. Biological functions of these monocyte-expressed genes were annotated and classified via Gene Ontology (GO) analysis. Furthermore, by extracting the overlapped genes from in vivoand in vitrodatasets, a core gene list including 541 unique genes was generated. Based on the core gene list, further gene-disease associations, pathway and network analyses were performed. Data analyses based on multiple bioinformatics tools produced a large body of biologically meaningful information, and revealed a number of genes such as SAMHD1, G6PD, GPD2and ENO1, which have been reported to be related to immune response, blood biology, bone remodeling, and cancer respectively. As a unique resource, this study can serve as a reference map for future in-depth research on monocytes biology and monocyte-involved human diseases.