M1836 A Protective Role of HSPS Against Various Gastrointestinal Diseases and Application of HSP-Inducing Drugs for These Diseases

phosphorylation were determined by Western blot using phospho-specific antibodies. Subcellular fractionation using specific lysis buffers allowed for analysis of Hsp27 accumulation in different cell compartments. Intestinal epithelial cell migration in response to scrapewounding was evaluated by serial photo-microscopy over 24 h and 48 h, and cell proliferation was measured by fluorescence-based Cell Titer Blue (CTB) assay over 24 h and 48 h, respectively. The specific inhibitor PD98059 (20 μM) as well as siRNA technology were used to specifically disrupt MAPK-pathway-activation. Results: Wounding induced Hsp27, MAPKAP-2as well as MAPKp38-phosphorylation in intestinal epithelial cells, which were associated with enhanced cell migration. A significant fraction of phospho-Hsp27(Ser82) translocated to the nucleus of wounded epithelial cells, while unphosphorylated Hsp27 predominantly remained in the cytoplasm. Disrupting MAPK signaling with PD98059 as well as knock-down of MAPKAP-2 using siRNA technology prevented wound-induced Hsp27as well as MAPKAP-2-phosphorylation and attenuated intestinal epithelial cell migration in response to wounding. Of note, inhibition of MAPKAP-2-signaling significantly reduced intestinal epithelial cell proliferation In Vitro. Conclusion: Wounding intestinal epithelial cell monolayers leads to MAPKAP-2-dependent Hsp27phosphorylation, which is associated with nuclear translocation of phospho-Hsp27, cell migration as well as cell proliferation in response to wounding. Thus, Hsp27 phosphorylation is a new component of the complex signaling profile activated by intestinal epithelial cells in reaction to wounding, aimed at rapidly reestablishing the integrity of the epithelial barrier under physiological conditions.