Influence of analytical procedures on miRNA expression analyses in saliva samples.

Aim of this study was to demonstrate the influence of different analytical procedures and techniques on the resulting miRNA expression profile in healthy control subjects and tumor patients using the oral squamous cell carcinoma (OSCC) model and to demonstrate the technical and biological reproducibility. Body fluids such as saliva are suitable for non-invasive miRNA analysis because ubiquitously circulating miRNA can be found in them. It was technically possible to distinguish between healthy and diseased samples based on the miRNA expression profile found. Regardless of the methodology used, good technical reproducibility of the results seems to be achievable. On the other hand, biological reproducibility was inadequate, which is why prompt sampling and sequencing is recommended. The data indicate that malignant lesions can be detected using miRNA signatures extracted from saliva. This could stimulate further research to establish standardized protocols and kits for sample collection, miRNA extraction, sequencing and interpretation of results.

Pathologically elevated cyclic hydrostatic pressure induces CD95-mediated apoptotic cell death in vascular endothelial cells.

We describe cyclic hydrostatic pressure of 200/100 mmHg with a frequency of 85/min as a hemodynamically relevant pathological condition enforcing apoptosis in endothelial cells (EC) after 24 h of treatment. This went along with an increase of CD95 and CD95L surface expression, shedding of CD95L into the supernatant, cleavage of caspase-3 and caspase-8, and elevated JNK-2, c-Jun, and CD95L mRNA expression. Furthermore, increased DNA-binding activity of the AP-1 transcription factor family members FRA-1 and c-Jun was observed. This activation was reduced by inhibition of JNK, which subsequently prevented elevated CD95L mRNA expression. Caspase inhibitors and a CD95L-neutralizing antibody also reduced EC apoptosis. Most of the pressure-induced events were most prominent at 24 and 48 h. However, after 48 h, the CD95/CD95L expression pattern switched back to CD95-/CD95L+ and the specific death rate decreased. Cyclic pathological hydrostatic pressure is a novel type of stress to EC that renders them susceptible to CD95/CD95L-mediated autoapoptosis and/or paracrine apoptosis accompanied by upregulation of intracellular molecules known to trigger both apoptosis and survival.