Vascular cell adhesion molecule-1 expression in human intestinal microvascular endothelial cells is regulated by PI 3-kinase/Akt/MAPK/NF-kappaB: inhibitory role of curcumin.
Endothelial activation and surface expression of cell adhesion molecules (CAMs) is critical for binding and recruitment of circulating leukocytes in tissues during the inflammatory response. Endothelial CAM expression plays a critical role in the intestinal microvasculature in inflammatory bowel disease (IBD), as blockade of leukocyte alpha4-integrin binding by gut endothelial CAM ligands has therapeutic benefit in IBD. Mechanisms underlying expression of vascular cell adhesion molecule (VCAM)-1, a ligand for alpha4-integrin in primary cultures of human intestinal microvascular endothelial cells (HIMEC) has not been defined. We investigated the effect of curcumin, phosphatidylinositol 3-kinase (PI 3-kinase)/protein kinase B (Akt), and mitogen-activated protein kinase (MAPK) inhibitors on VCAM-1 expression and function in HIMEC. CAM expression was assessed and HIMEC-leukocyte adhesion was visualized under static and flow conditions. Western blotting and in vitro kinase assays were used to assess Akt and MAPK activation. Nuclear factor-kappaB (NF-kappaB) activation and nuclear translocation of its p65 subunit were determined. Tumor necrosis factor (TNF)-alpha/lipopolysaccharide (LPS)-induced VCAM-1 expression in HIMEC was suppressed by Akt small-interfering RNA, curcumin, and inhibitors of NF-kappaB (SN-50), p38 MAPK (SB-203580) and PI 3-kinase/Akt (LY-294002). VCAM-1 induction was partially suppressed by p44/42 MAPK (PD-098059) but unaffected by c-Jun NH2-terminal kinase (SP-600125) inhibition. Curcumin inhibited Akt/MAPK/NF-kappaB activity and prevented nuclear translocation of the p65 NF-kappaB subunit following TNF-alpha/LPS. At physiological shear stress, curcumin attenuated leukocyte adhesion to TNF-alpha/LPS-activated HIMEC monolayers. In conclusion, curcumin inhibited the expression of VCAM-1 in HIMECs through blockade of Akt, p38 MAPK, and NF-kappaB. Curcumin may represent a novel therapeutic agent targeting endothelial activation in IBD.
Binion
David G
DG
Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
Heidemann
Jan
J
Li
Mona S
MS
Nelson
Victoria M
VM
Otterson
Mary F
MF
Rafiee
Parvaneh
P
D021581:Active Transport, Cell Nucleus; D002448:Cell Adhesion / Q000187:drug effects; D015815:Cell Adhesion Molecules; D002478:Cells, Cultured; D003474:Curcumin / Q000494:pharmacology*; D042783:Endothelial Cells / Q000187:drug effects* / Q000201:enzymology; D005765:Gastrointestinal Agents / Q000494:pharmacology*; D006801:Humans; D007136:Immunoglobulins / Q000378:metabolism; D007422:Intestines / Q000098:blood supply*; D007962:Leukocytes / Q000187:drug effects / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D055806:Microvessels / Q000187:drug effects / Q000201:enzymology; D009088:Mucoproteins / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D051996:Transcription Factor RelA / Q000037:antagonists & inhibitors* / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D019010:Vascular Cell Adhesion Molecule-1 / Q000235:genetics / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism
D015815:Cell Adhesion Molecules; D003474:Curcumin; D005765:Gastrointestinal Agents; D007136:Immunoglobulins; D008070:Lipopolysaccharides; D009088:Mucoproteins; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt; D051996:Transcription Factor RelA; D014409:Tumor Necrosis Factor-alpha; D019010:Vascular Cell Adhesion Molecule-1; D048051:p38 Mitogen-Activated Protein Kinases; C504265:MADCAM1 protein, human; C498143:RELA protein, human