The study of hepatic NF-κB transcription dynamics via fluorescent image analysis

This paper presents an imaging technique for assessing the stimulation of H35 cells by TNF-alpha. Specifically, fluorescence from the stimulated cells is measured in order to produce intensity profiles that describe the dynamics of the NF-kappaB transcription factor. The approach offers a cost-effective, non-invasive and quantifiable alternative to traditional techniques used to acquire this intracellular information. The analysis successfully extracts information from low contrast images and produces profiles comparable to those published in previous literature. The images are de-noised using wavelets, automatic thresholding is performed and connected component analysis is carried out, so that it is possible to track fluorescent cell clusters in a series of images taken at a high sample rate. The resulting profiles showed that the level of NF-kappaB in the cells increased as the concentration of stimulating TNF-alpha increased. They also provided supporting evidence for the hypothesis that the time of maximum NF-kappaB response does not depend on the initial stimulating TNF-a concentration. Experimental results such as these are crucial for the development and validation of mathematical models describing intracellular signal transduction pathways.