Non-cellulosic glucans as inductors for differentiation of human keratinocytes

The epidermis is a dynamic renewing structure, principally formed by highly specialized keratinocytes. During a carefully choreographed program of differentiation keratinocytes undergo complex morphological and biochemical changes.

As chitooligomers were shown to stimulate cellular differentiation (1), β-D-glucans are supposed to induce human keratinocyte differentiation. The aim of the study was to identify glucans as inductors for cell differentiation, to establish an in vitro test system for distinct structure-activity relations and to identify the molecular targets for interaction of the glucans with the keratinocytes.

Using a combination of qPCR for quantification of differentiation-specific genes, western blotting for differentiation-specific proteins and laser-scanning microscopy for verification of results on cellular differentiation we obtained two selected candidates with a high and promising potential of inducing cellular differentiation from a variety of β-glucans.

Lichenan (β-1,3/1,4-glucan) from Lichen islandicus (L) and xyloglucan (β-1,4/1,6-glucan with defined xylose and galactose side chains) from Tropaeolum majus (X) each 100 µg/ml, turned out to be inductors of epidermal differentiation.

qPCR analyses revealed the gene expression of differentiation related genes to be regulated in a structure-dependent manner by the test compounds. Thus L increased mRNA levels of both differentiation markers involucrin and cytokeratin 10 at an early stage, whereas X increased mRNA levels in a suqsequent stage. Besides the differences in functionality among the test compounds along with an up- and down-regulation in a time-dependent manner, there also could be found a different functionality for the positive controls compared to the test compounds.

References:

[1] Deters A, Petereit F, Schmidgall J, Hensel A (2008) N-Acetyl-D-glucosamine oligosaccharides induce mucin secretion from colonic tissue and induce differentiation of human keratinocytes. J. Pharm. Pharmacol. 60(2), 197 – 204