| Popis: |
Ethanol consumption disrupts the intestinal barrier and sensitizes hepatic macrophages to inflammatory stimuli. We have recently shown that hyaluronan (HA) with an average molecular weight of 35kDa (HA35) prevents sensitization of TLR4 signaling in lipopolysaccharide (LPS) challenged Kupffer cells isolated from ethanol-fed rats. To determine whether HA35 would prevent liver injury in response to ethanol, eight to ten week old female C57BL/6J mice were fed a control or ethanol (2d of 1% and 2d of 6% v/v) containing Lieber-DeCarli diet. Mice were treated with HA35 or sterile saline by daily gavage for the last three days. HA35 treatment prevented ethanol-induced increases in hepatocyte apoptosis and expression of proinflammatory cytokine and chemokine mRNA in liver. HA35 prevented ethanol-induced decreases in miR181b-3 a suppressor of NF-kB responses through targeted downregulation of the nuclear transporter importin a5 in non-parenchymal cells. Ethanol increased the nuclear translocation of phosphorylation of NF-kB subunit p65 in the livers of ethanol-fed mice, but HA35 prevented translocation comparable to control. HA35 also protected the intestine from ethanol-induced injury. Ethanol feeding increased intestinal permeability as assessed by increased the portal concentration of endotoxin but not in mice treated with HA35. Short-term ethanol feeding increased the thickness of the lamina propria in the distal colon and decreased the co-localization of ZO-1 and occludin at tight junctions in both the proximal and distal colon. HA35 prevented these effects of ethanol. In differentiated Caco-2 cells, ethanol decreased the localization of ZO-1 and occludin at tight junctions and increased FITC-inulin permeability. Pre-treatment with HA35 prevented these changes. When the hyaluronan receptor Layilin was knocked down in Caco-2 cells, HA35 was no longer able to protect from ethanol-induced loss of tight junctions. Taken together these data identify HA35 as a therapeutic for preventing loss of intestinal integrity and liver injury due to alcohol consumption. |
