Fibronectin-mediated cell spreading requires ABBA-Rac1 signaling

Exosomal microRNA-92b Is a Diagnostic Biomarker in Breast Cancer and Targets Survival-Related MTSS1L to Promote Tumorigenesis

Exosomal microRNAs (miRNAs) are novel, non-invasive biomarkers for facilitating communication and diagnosing cancer. However, only a few studies have investigated their function and role in the clinical diagnosis of breast cancer. To address this gap, we established a stable cell line, MDA-MB-231-CD63-RFP, and recruited 112 female participants for serum collection. We screened 88 exosomal miRNAs identified through microarray analysis of 231-CD63 and literature screening using real-time PCR; only exosomal miR-92b-5p was significantly increased in patients with breast cancer. It had a significant correlation with stage and discriminated patients from the control with an AUC of 0.787. Exosomal miR-92b-5p impacted the migration, adhesion, and spreading ability of normal human mammary epithelial recipient cells through the downregulation of the actin dynamics regulator MTSS1L. In clinical breast cancer tissue, the expression of MTSS1L was significantly inversely correlated with tissue miR-92b-5p, and high expression of MTSS1L was associated with better 10-year overall survival rates in patients undergoing hormone therapy. In summary, our studies demonstrated that exosomal miR-92b-5p might function as a non-invasive body fluid biomarker for breast cancer detection and provide a novel therapeutic strategy in the axis of miR-92b-5p to MTSS1L for controlling metastasis and improving patient survival.

BAR domain proteins-a linkage between cellular membranes, signaling pathways, and the actin cytoskeleton

Actin filament assembly typically occurs in association with cellular membranes. A large number of proteins sit at the interface between actin networks and membranes, playing diverse roles such as initiation of actin polymerization, modulation of membrane curvature, and signaling. Bin/Amphiphysin/Rvs (BAR) domain proteins have been implicated in all of these functions. The BAR domain family of proteins comprises a diverse group of multi-functional effectors, characterized by their modular architecture. In addition to the membrane-curvature sensing/inducing BAR domain module, which also mediates antiparallel dimerization, most contain auxiliary domains implicated in protein-protein and/or protein-membrane interactions, including SH3, PX, PH, RhoGEF, and RhoGAP domains. The shape of the BAR domain itself varies, resulting in three major subfamilies: the classical crescent-shaped BAR, the more extended and less curved F-BAR, and the inverse curvature I-BAR subfamilies. Most members of this family have been implicated in cellular functions that require dynamic remodeling of the actin cytoskeleton, such as endocytosis, organelle trafficking, cell motility, and T-tubule biogenesis in muscle cells. Here, we review the structure and function of mammalian BAR domain proteins and the many ways in which they are interconnected with the actin cytoskeleton.

Comparative analysis of TCDD-induced AhR-mediated gene expression in human, mouse and rat primary B cells

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a persistent environmental pollutant that activates the aryl hydrocarbon receptor (AhR) resulting in altered gene expression. In vivo, in vitro, and ex vivo studies have demonstrated that B cells are directly impaired by TCDD, and are a sensitive target as evidenced by suppression of antibody responses. The window of sensitivity to TCDD-induced suppression of IgM secretion among mouse, rat and human B cells is similar. Specifically, TCDD must be present within the initial 12h post B cell stimulation, indicating that TCDD disrupts early signaling network(s) necessary for B lymphocyte activation and differentiation. Therefore, we hypothesized that TCDD treatment across three different species (mouse, rat and human) triggers a conserved, B cell-specific mechanism that is involved in TCDD-induced immunosuppression. RNA sequencing (RNA-Seq) was used to identify B cell-specific orthologous genes that are differentially expressed in response to TCDD in primary mouse, rat and human B cells. Time course studies identified TCDD-elicited differential expression of 515 human, 2371 mouse and 712 rat orthologous genes over the 24-h period. 28 orthologs were differentially expressed in response to TCDD in all three species. Overrepresented pathways enriched in all three species included cytokine-cytokine receptor interaction, ECM-receptor interaction, focal adhesion, regulation of actin cytoskeleton and pathways in cancer. Differentially expressed genes functionally associated with cell-cell signaling in humans, immune response in mice, and oxidation reduction in rats. Overall, these results suggest that despite the conservation of the AhR and its signaling mechanism, TCDD elicits species-specific gene expression changes.

Altered microRNA expression profiles in lung damage induced by nanosized SiO2

The objective of the present research is to explore miRNAs expression profiles in lung tissue of rat treated by nanosized SiO₂ in the light of normal at diverse dosages, time, predict their target genes, and probe the biological function and regulation of miRNA in the lung damage process caused by nanosized SiO₂. Up-regulation of rno-miR-208, rno-miR-212 and rno-miR-18a in lung tissue mainly characterized by inflammation of SD rats caused by nanosized SiO₂ particles instilled intratracheally at 7^th, 15^th 30^th d using Illumina HiSeq2000 sequencing technique and were further verified by quantitative reverse transcriptase polymerase chain reaction (qRT PCR) assay. Lung damage is mainly with characteristics of lung interstitial fibrosis, upregulation of rno-miR-212, rno-miR-144, rno-miR-702-3p, rno-miR-379 and rno-miR-127, down-regulation of rno-miR-541 at 60^th, 90^th d post-exposure. As target genes of rno-miR-208, rno-miR-212 and rno-miR-18a respectively, there was no statistical significance of programmed cell death 4 (PDCD4), LIN28B and connective tissue growth factor (CTGF) mRNA expression level (P > 0.05) compared to β-actin as internal controls detected by Real-time quantitative PCR. The differences in protein gray value ratio of PDCD4, LIN28B and CTGF detected by Western blotting test were statistically significant (P < 0.05). These results suggested that miR-208, miR-212 and miR-18a may take effects in rats' lung damage lead by nanosized SiO₂. Their target genes of PDCD4, LIN28B and CTGF functioned in translation level of target genes in regulation of inflammatory signaling pathways and involved in the formation of tissue fibrosis.