Modulation of neutrophil motility by curcumin: implications for inflammatory bowel disease.
BACKGROUND
Neutrophils (PMN) are the first cells recruited at the site of inflammation. They play a key role in the innate immune response by recognizing, ingesting, and eliminating pathogens and participate in the orientation of the adaptive immune responses. However, in inflammatory bowel disease (IBD) transepithelial neutrophil migration leads to an impaired epithelial barrier function, perpetuation of inflammation, and tissue destruction via oxidative and proteolytic damage. Curcumin (diferulolylmethane) displays a protective role in mouse models of IBD and in human ulcerative colitis, a phenomenon consistently accompanied by a reduced mucosal neutrophil infiltration.


METHODS
We investigated the effect of curcumin on mouse and human neutrophil polarization and motility in vitro and in vivo.


RESULTS
Curcumin attenuated lipopolysaccharide (LPS)-stimulated expression and secretion of macrophage inflammatory protein (MIP)-2, interleukin (IL)-1β, keratinocyte chemoattractant (KC), and MIP-1α in colonic epithelial cells (CECs) and in macrophages. Curcumin significantly inhibited PMN chemotaxis against MIP-2, KC, or against conditioned media from LPS-treated macrophages or CEC, a well as the IL-8-mediated chemotaxis of human neutrophils. At nontoxic concentrations, curcumin inhibited random neutrophil migration, suggesting a direct effect on neutrophil chemokinesis. Curcumin-mediated inhibition of PMN motility could be attributed to a downregulation of PI3K activity, AKT phosphorylation, and F-actin polymerization at the leading edge. The inhibitory effect of curcumin on neutrophil motility was further demonstrated in vivo in a model of aseptic peritonitis.


CONCLUSIONS
Our results indicate that curcumin interferes with colonic inflammation partly through inhibition of the chemokine expression and through direct inhibition of neutrophil chemotaxis and chemokinesis.
Larmonier
C B
CB
Department of Pediatrics, Steele Children's Research Center, University of Arizona Health Sciences Center, Tucson, Arizona 85724, USA.
Midura-Kiela
M T
MT
Ramalingam
R
R
Laubitz
D
D
Janikashvili
N
N
Larmonier
N
N
Ghishan
F K
FK
Kiela
P R
PR
D000199:Actins / Q000235:genetics / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D054405:Chemokine CCL3 / Q000235:genetics / Q000378:metabolism; D002634:Chemotaxis, Leukocyte / Q000187:drug effects; D003106:Colon / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D003474:Curcumin / Q000494:pharmacology*; D004195:Disease Models, Animal; D006801:Humans; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D017737:Macrophages, Peritoneal / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D020556:Neutrophil Infiltration; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
D000199:Actins; D054405:Chemokine CCL3; D012333:RNA, Messenger; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D003474:Curcumin