Influence of Ispaghula seed husk polysaccharides on the gene expression of normal human skin keratinocytes (NHK)

Deters A

Abstract

An acidic xyloglucan isolated from Ispaghula seed husks (IP) increased the proliferation of human keratinocytes1. Since the underlying mechanism remained unclear a microarray study was performed to elucidate the influenced signal pathways. Cells were incubated with 10µg/ml IP for six hours before mRNA isolation and transcription. The cDNA was labeled with Cy3 (untreated) and Cy5 (treated cells). After hybridization to the PIQORTM Skin Microarray the fluorescent label incorporation rate was calculated. It was noticed that 49% of the spotted genes were not expressed neither in treated nor untreated NHK. Compared to the untreated NHK cells incubated with IP exhibited no difference in expression of 27% genes but 15% were slightly and 9% were significantly regulated, whereby mostly a down regulation occurred. The most influence on the expression belongs to genes of extra cellular matrix (ECM) and cytokine signaling followed by transcription factors and parts of the cell metabolism. Minor control on gene expression was observed in regard of proliferation, inflammation, cell cycle, differentiation cytoskeleton and DNA repair related genes. Whereas in the most cases a down regulation occurred effected genes of the cytoskeleton were mostly up-regulated and in case of proliferation related genes the number of down regulated genes equates the number of up-regulated genes. In conclusion the gene expression pattern is consistent with the results observed in preliminary work but it poses the question how the multiple signal pathways work together.