Salmonella-driven Intestinal Edema in Mice is Characterized by Tensed Fibronectin Fibers

Intestinal edema is a common manifestation of numerous gastrointestinal diseases and is characterized by the accumulation of fluid in the interstitial space of the intestinal wall. Technical advances in laser capture microdissection and low-biomass proteomics now allow us to specifically characterize the intestinal edema proteome. Our data identifies a high abundance of antimicrobial factors, but also highlights major contributions from the blood clotting system, extracellular matrix (ECM) and protease - protease inhibitor networks. The ECM is a complex fibrillar network of macromolecules that provides structural and mechanical support to the intestinal tissue. One abundant component of the ECM observed in the Salmonella-driven intestinal edema is the mechanosensitive glycoprotein fibronectin. Using mechanosensitive staining of fibronectin reveals a solely tensed molecular conformation of fibronectin fibers present in the edema, in contrast to other cecal tissue areas, despite the high abundance of proteases able to cleave fibronectin. Co-staining for fibrin(ogen) indicates the formation of a provisional matrix, similar to what is observed in response to skin injury. The absence of low tensional fibronectin fibers and the additional finding of a high number of protease inhibitors in the edema proteome could indicate a critical role of stretched fibronectin fibers in maintaining tissue integrity in the severely inflamed cecum. Understanding these processes may provide valuable functional diagnostic markers of intestinal disease progression. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=104 SRC="FIGDIR/small/550515v1_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@1318c52org.highwire.dtl.DTLVardef@1f35d21org.highwire.dtl.DTLVardef@67370borg.highwire.dtl.DTLVardef@4ec7e6_HPS_FORMAT_FIGEXP M_FIG C_FIG