Effect of small interfering RNA transfection on FAK and DLC1 mRNA expression in OVCAR-3

DLC1 promotes mechanotransductive feedback for YAP via RhoGAP-mediated focal adhesion turnover

Angiogenesis is a tightly controlled dynamic process demanding a delicate equilibrium between pro-angiogenic signals and factors that promote vascular stability. The spatiotemporal activation of the transcriptional co-factors YAP (herein referring to YAP1) and TAZ (also known WWTR1), collectively denoted YAP/TAZ, is crucial to allow for efficient collective endothelial migration in angiogenesis. The focal adhesion protein deleted-in-liver-cancer-1 (DLC1) was recently described as a transcriptional downstream target of YAP/TAZ in endothelial cells. In this study, we uncover a negative feedback loop between DLC1 expression and YAP activity during collective migration and sprouting angiogenesis. In particular, our study demonstrates that signaling via the RhoGAP domain of DLC1 reduces nuclear localization of YAP and its transcriptional activity. Moreover, the RhoGAP activity of DLC1 is essential for YAP-mediated cellular processes, including the regulation of focal adhesion turnover, traction forces, and sprouting angiogenesis. We show that DLC1 restricts intracellular cytoskeletal tension by inhibiting Rho signaling at the basal adhesion plane, consequently reducing nuclear YAP localization. Collectively, these findings underscore the significance of DLC1 expression levels and its function in mitigating intracellular tension as a pivotal mechanotransductive feedback mechanism that finely tunes YAP activity throughout the process of sprouting angiogenesis.

MicroRNAs in acute pancreatitis: From pathogenesis to novel diagnosis and therapy

Acute pancreatitis (AP) is an inflammatory disorder initiated by activation of pancreatic zymogens, leading to pancreatic injury and systemic inflammatory response. MicroRNAs (miRNAs) have emerged as important regulators of gene expression and key players in human physiological and pathological processes. Discoveries over the past decade have confirmed that altered expression of miRNAs is implicated in the pathogenesis of AP. Indeed, a number of miRNAs have been found to be dysregulated in various cell types involved in AP such as acinar cells, macrophages, and lymphocytes. These aberrant miRNAs can regulate acinar cell necrosis and apoptosis, local and systemic inflammatory response, thereby contributing to the initiation and progression of AP. Moreover, patients with AP possess unique miRNA signatures when compared with healthy individuals or those with other diseases. In view of their stability and easy detection, therefore, miRNAs have the potential to act as biomarkers for the diagnosis and assessment of patients with AP. In this review, we provide an overview of the novel cellular and molecular mechanisms underlying the roles of miRNAs during the disease processes of AP, as well as the potential diagnosis and therapeutic biomarkers of miRNAs in patients with AP.

Targeting MicroRNA Function in Acute Pancreatitis

Acute pancreatitis (AP) is a common gastrointestinal disorder that featured by acute inflammatory responses leading to systemic inflammatory response syndrome (SIRS) or multiple organ failure. A worldwide increase in annual incidence has been observed during the past decade with high acute hospitalization and mortality. Lack of any specific treatment for AP, even to this day, is a reminder that there is much to be learned about the exact pathogenesis of AP. Fortunately, the discovery of microRNA (miRNA) has started an entirely new thought process regarding the molecular mechanism associated with the disease processes. Given the extensive effort made on miRNA research, certain types of miRNA have been identified across a variety of biological processes, including cell differentiation, apoptosis, metabolism, and inflammatory responses. Mutations in miRNA sequences or deregulation of miRNA expression may contribute to the alteration of a pivotal physiological function leading to AP. Designing miRNA-related tools for AP diagnosis and treatment presents a novel and potential research frontier. In this mini-review, we summarize the current knowledge of various miRNAs closely interacting with AP and the possible development of targeted miRNA therapies in this disease, which may benefit the development of potential disease biomarkers and novel treatment targets for future medical implications.

Expressions of miR-22 and miR-135a in acute pancreatitis

This study examined the expressions of miR-22 and miR-135a in rats with acute edematous pancreatitis (AEP) and their target genes in order to shed light on the involvement of miR-22 and miR-135a in the pathogenesis of acute pancreatitis (AP). The in vivo model of AEP was established by introperitoneal injection of L-arginine (150 mg/kg) in rats. The miRNA microarray analysis was used to detect the differential expression of miRNAs in pancreatic tissue in AEP and normal rats. The in vitro AEP model was established by inducing the rat pancreatic acinar cell line (AR42J) with 50 ng/mL recombinant rat TNF-α. Real-time quantitative RT-PCR was employed to detect the expression of miR-22 and miR-135a in AR42J cells. Lentiviruses carrying the miRNA mimic and anti-miRNA oligonucleotide (AMO) of miR-22 and miR-135a were transfected into the AR42J cells. The AR42J cells transfected with vehicle served as control. Western blotting was used to measure the expression of activated caspase3 and flow cytometry analysis to detect the apoptosis of AR42J cells. Targets of miR-22 and miR-135a were predicted by using TargetScan, miRanda, and TarBase. Luciferase reporter assay and quantitative real-time RT-PCR were performed to confirm whether ErbB3 and Ptk2 were the target gene of miR-22 and miR-135a, respectively. The results showed that the expression levels of miR-22 and miR-135a were obviously increased in AEP group compared with the control group in in-vivo and in-vitro models. The expression levels of miR-22 and miR-135a were elevated conspicuously and the expression levels of their target genes were reduced significantly in AR42J cells transfected with lentiviruses carrying the miRNA mimic. The apoptosis rate was much higher in the TNF-α-induced cells than in non-treated cells. The AR42J cells transfected with miRNA AMOs expressed lower level of miR-22 and miR-135a and had lower apoptosis rate, but the expression levels of ErbB3 and Ptk2 were increased obviously. It was concluded that the expression levels of miR-22 and miR-135a were elevated in AEP. Up-regulating the expression of miR-22 and miR-135a may promote the apoptosis of pancreatic acinar cells by repressing ErbB3 and Ptk2 expression in AEP.

Bioluminescence determination of active caspase-3 in single apoptotic cells

Caspase-3 is an executive caspase, in the central position within apoptotic machinery. Apoptosis as a way of programmed cell death is a physiological process that plays an essential role in the development and homeostasis maintenance; moreover, its deregulations are linked to tumor progression or various autoimmune disorders. Therefore, an investigation of apoptosis pathways on the level of individual cells is not only of biological but also medical importance. In this work we report on the development of a high-sensitivity instrumentation and protocol for detection of active caspase-3 in individual mammalian apoptotic cells. The technology is based on the specific cleavage of modified luciferin by caspase-3, an immediate bioluminescence reaction of free luciferin with luciferase followed by emissions of photons and their detection by photomultiplier tube working in the photon counting regime. Three different instrumental arrangements are compared for the determination of caspase-3 in free cells or tissue samples. Thus, in our best miniaturized system the mean amount as low as about 6.5 fg corresponding to 122 000 molecules of caspase-3 can be detected in individual apoptotic mouse leg cells.