Anti-PTK2 monoclonal antibody, clone FQ2942Z

Caveolae have been hypothesized to be involved in Ca2+ signaling. By electron microscopy, caveolae were observed to be apposed to the endoplasmic reticulum (ER), which is a major intracellular Ca2+ pool. In the present study, we examined the relationship between caveolae and the ER when the distribution of the latter was changed by depolymerization of microtubules. Double immunofluorescence microscopy for detection of caveolin and the ER antigens, and time-lapse observation of green fluorescent protein (GFP)-tagged caveolin were employed. in normal human fibroblasts and PtK2 cells, the ER was seen as a network extending throughout the cytoplasm, and most caveolin occurred in patches along the cell edge. When microtubules were depolymerized by Colcemid or nocodazole, the ER became retracted from the cell periphery and aggregated around the nucleus; in the same cells, caveolin was not seen along the cell edge, but was aligned along the edge of the retracted ER. By time-lapse analysis, GFP-caveolin expressed in PtK2 cells was observed to move from the cell periphery toward the cell center in Colcemid-treated cells. The result shows that the apposition of caveolae and the ER is maintained even after the gross distributional change, and suggests a mechanical linkage between the two organelles.

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-alpha. 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-alpha-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.