Variable definitions and treatment approaches for atrial functional mitral regurgitation: A scoping review of the literature.

Objectives: Atrial functional mitral regurgitation (AFMR) is a subtype of functional mitral regurgitation due to longstanding atrial fibrillation (AF) or heart failure with preserved ejection fraction. The variation in AFMR' definition and the common mode of treatment described in the literature remain unknown.

Methods: We performed a scoping review of studies that surgically treated AFMR to characterize the existing variability in the definition of AFMR, the type of operations performed for AFMR valvulopathy, and the treatment for the chronic AF.

Post-transcriptional regulation of programmed cell death 4 (PDCD4) mRNA by the RNA-binding proteins human antigen R (HuR) and T-cell intracellular antigen 1 (TIA1).

Post-transcriptional processing of mRNA transcripts plays a critical role in establishing the gene expression profile of a cell. Such processing events are mediated by a host of factors, including RNA-binding proteins and microRNAs. A number of critical cellular pathways are subject to regulation at multiple levels that allow fine-tuning of key biological responses.

Combining single RNA sensitive probes with subdiffraction-limited and live-cell imaging enables the characterization of virus dynamics in cells.

The creation of fluorescently labeled viruses is currently limited by the length of imaging observation time (e.g., labeling an envelope protein) and the rescue of viral infectivity (e.

Characterization of mRNA-cytoskeleton interactions in situ using FMTRIP and proximity ligation.

Many studies have demonstrated an association between the cytoskeleton and mRNA, as well as the asymmetric distribution of mRNA granules within the cell in response to various signaling events. It is likely that the extensive cytoskeletal network directs mRNA transport and localization, with different cytoskeletal elements having their own specific roles. In order to understand the spatiotemporal changes in the interactions between the mRNA and the cytoskeleton as a response to a stimulus, a technique that can visualize and quantify these changes across a population of cells while capturing cell-to-cell variations is required.

Quantifying RNA-protein interactions in situ using modified-MTRIPs and proximity ligation.

The stabilization, translation and degradation of RNA are regulated by interactions between trans-acting factors, such as microRNA and RNA-binding proteins (RBP). In order to investigate the relationships between these events and their significance, a method that detects the localization of these interactions within a single cell, as well as their variability across a cell population, is needed. To visualize and quantify RNA-protein interactions in situ, we developed a proximity ligation assay (PLA) that combined peptide-modified, multiply-labelled tetravalent RNA imaging probes (MTRIPs), targeted to sequences near RBP binding sites, with proximity ligation and rolling circle amplification (RCA).

Human respiratory syncytial virus nucleoprotein and inclusion bodies antagonize the innate immune response mediated by MDA5 and MAVS.

Currently, the spatial distribution of human respiratory syncytial virus (hRSV) proteins and RNAs in infected cells is still under investigation, with many unanswered questions regarding the interaction of virus-induced structures and the innate immune system. Very few studies of hRSV have used subcellular imaging as a means to explore the changes in localization of retinoic-acid-inducible gene-I (RIG-I)-like receptors or the mitochondrial antiviral signaling (MAVS) protein, in response to the infection and formation of viral structures. In this investigation, we found that both RIG-I and melanoma differentiation-associated gene 5 (MDA5) colocalized with viral genomic RNA and the nucleoprotein (N) as early as 6 h postinfection (hpi).

Probes for intracellular RNA imaging in live cells.

RNA localization, dynamics, and regulation are becoming increasingly important to our basic understanding of gene expression and RNA virus pathogenesis. An improved understanding of these processes will be necessary in order to identify new drug targets, as well as to create models of gene expression networks. Much of this new understanding will likely come from imaging studies of RNA, which can generate the spatiotemporal information necessary to characterize RNA within the cellular milieu.