leupeptins and Inflammatory-Bowel-Diseases

Monocyte chemotactic protein 1-induced protein 1 (MCPIP-1) is highly expressed in activated immune cells and plays an important role in negatively regulating immune responses. However, its role in regulating neutrophil functions in the pathogenesis of inflammatory bowel disease (IBD) is still unclear. Here, we found that MCPIP-1 was markedly increased at both the transcriptional and translational levels in inflamed mucosa of IBD patients compared with healthy controls, which was mainly expressed in neutrophils. Interestingly, MG-132, a proteasome inhibitor reducing the degradation of MCPIP-1, further facilitated neutrophils to express MCPIP-1

Topics: Adult; Animals; Blotting, Western; Chemokine CCL2; Enzyme-Linked Immunosorbent Assay; Female; Fluorescent Antibody Technique; Humans; Inflammatory Bowel Diseases; Interleukin-1beta; Interleukin-6; Interleukin-8; Leupeptins; Male; Mice; Mice, Inbred C57BL; Middle Aged; Neutrophils; Real-Time Polymerase Chain Reaction; Ribonucleases; Transcription Factors; Tumor Necrosis Factor-alpha; Young Adult

Immunoproteasome up-regulation enhances the processing of nuclear factor-kappaB (NF-kappaB) and degradation of IkappaBalpha, which correlates with increased amounts of NF-kappaB in the various cells. Aberrant activation of NF-kappaB is involved in the pathogenesis of inflammatory bowel disease (IBD). The aim of this study was to elucidate the effect of proteasome inhibitor MG132 on experimental IBD. We investigated the effects of MG132 on intestinal inflammation and epithelial regeneration in both interleukin-10-deficient (IL-10(-/-)) mice and mice with dextran sulphate sodium (DSS)-induced colitis. Body weight, histological findings and tumour necrosis factor (TNF)-alpha mRNA expression, epithelial cell proliferation and NF-kappaB p65 activity in colonic tissues were examined. The effects of MG132 on cell proliferation, migration and multiple drug resistance 1 (MDR1) gene expression were determined in vitro. MG132 ameliorated intestinal inflammation of IL-10(-/-) mice by decreasing TNF-alpha mRNA expression in the colonic tissues, which was associated with suppression of NF-kappaB activation, and reduced significantly the number of Ki-67-positive intestinal epithelial cells. On the other hand, MG132 did not reduce intestinal inflammation in mice with DSS-induced colitis, and delayed significantly the recovery of body weight and epithelial regeneration. MG132 also suppressed significantly epithelial cell proliferation, cell migration and MDR1 gene expression in vitro. Proteasome inhibition reduces T cell-mediated intestinal inflammation, but may interrupt both epithelial regeneration and barrier function of colonic mucosa. Optimal use of proteasome inhibitor should be kept in mind when we consider its clinical application for patients with IBD.

Topics: Animals; Cell Proliferation; Colon; Cysteine Proteinase Inhibitors; Dextran Sulfate; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Evaluation, Preclinical; Female; Gene Expression Regulation; Inflammatory Bowel Diseases; Interleukin-10; Intestinal Mucosa; Leupeptins; Mice; Mice, Inbred C57BL; RNA, Messenger; Transcription Factor RelA; Tumor Necrosis Factor-alpha

Mucosal addressin cell adhesion molecule-1 (MAdCAM-1) is a 60-kDa endothelial cell adhesion glycoprotein that regulates lymphocyte trafficking to Peyer's patches and lymph nodes. Although it is widely agreed that MAdCAM-1 induction is involved in chronic gut inflammation, few studies have investigated regulation of MAdCAM-1 expression. We used two endothelial lines [bEND.3 (brain) and SVEC (high endothelium)] to study the signal paths that regulate MAdCAM-1 expression in response to tumor necrosis factor (TNF)-alpha using RT-PCR, blotting, adhesion, and immunofluorescence. TNF-alpha induced both MAdCAM-1 mRNA and protein in a dose- and time-dependent manner. This induction was tyrosine kinase (TK), p42/44, p38 mitogen-activated protein kinase (MAPK), and nuclear factor (NF)-kappa B/poly-ADP ribose polymerase (PARP) dependent. Because MAdCAM-1 is regulated via MAPKs, we examined mitogen/extracellular signal-regulated kinase (MEK)-1/2 activation in SVEC. We found that MEK-1/2 is activated by TNF-alpha within minutes and is dependent on TK and p42/44 MAPKs. Similarly, TNF-alpha activated NF-kappa B through TK, p42/44, p38 MAPKs, and PARP pathways in SVEC cells. MAdCAM-1 was also shown to be frequently distributed to endothelial junctions both in vitro and in vivo. Cytokines like TNF-alpha stimulate MAdCAM-1 in high endothelium via TK, p38, p42/22 MAPKs, and NF-kappa B/PARP. MAdCAM-1 expression requires NF-kappa B translocation through both direct p42/44 and indirect p38 MAPK pathways in high endothelial cells.

Topics: Alkaloids; Animals; Benzophenanthridines; Benzopyrans; Carbazoles; Cell Adhesion Molecules; Cell Line, Transformed; Cysteine Proteinase Inhibitors; Endothelium; Enzyme Inhibitors; Flavonoids; Fluorescent Antibody Technique; Gene Expression; Genistein; Imidazoles; Immunoglobulins; In Vitro Techniques; Indoles; Inflammatory Bowel Diseases; Intestinal Mucosa; Isoquinolines; Leupeptins; MAP Kinase Signaling System; Mice; Mucoproteins; NF-kappa B; Phenanthridines; Pyridines; RNA, Messenger; Tumor Necrosis Factor-alpha