HMGB1 is a chromatin-binding, architectural protein residing in the eukaryotic cells nucleus that was recently showed to have an extracellular role as a cytokine. Because it is secreted by activated monocytes and macrophages in response to the same stimuli that activate the NF-κB classical pathway (IL-1β, TNF and LPS) and because it induces survival and proliferation in mesoangioblast cells (mesodermal stem cells that are associated with the wall of fetal and postnatal vessels), we want to investigate if HMGB1 acts on the cells through NF-κB. We stimulated mesoangioblast cells for 16 hours in a serum-free medium, using as a matched negative control the same cells kept for 16 hours in only serum-free medium. After the stimulation, we extracted the total RNAs from the two samples and we checked their quality through Taqman PCR, normalizing the values with GADPH (see the protocol). The genes used are selected among the well-known NF-κB target genes (VCAM, Rantes, IκBα). The real time PCR showed that there is a significant difference between the stimulated and unstimulated samples, so we used them for a Microarray screening. We are now validating the data of the screening again in part using TaqMan 'real time' PCR or Cyber Green based PCR assays.