Effects Of hBD-3 Research Articles

Human β-Defensin 3 Reduces TNF-α-Induced Inflammation and Monocyte Adhesion in Human Umbilical Vein Endothelial Cells.

The aim of this study was to investigate the role of human β-defensin 3 (hBD3) in the initiation stage of atherosclerosis with human umbilical vein endothelial cells (HUVECs) triggered by tumor necrosis factor- (TNF-) α. The effects of hBD3 on TNF-α-induced endothelial injury and inflammatory response were evaluated. Our data revealed that first, hBD3 reduced the production of interleukin-6 (IL-6), IL-8, monocyte chemoattractant protein-1 (MCP-1), and macrophage migration inhibitory factor (MIF) in HUVECs in a dose-dependent manner. In addition, hBD3 significantly prevented intracellular reactive oxygen species (ROS) production by HUVECs. Second, western blot analysis demonstrated that hBD3 dose-dependently suppressed the protein levels of intracellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in TNF-α-induced HUVECs. As a result, hBD3 inhibited monocyte adhesion to TNF-α-treated endothelial cells. Additionally, hBD3 suppressed TNF-α-induced F-actin reorganization in HUVECs. Third, hBD3 markedly inhibited NF-κB activation by decreasing the phosphorylation of IKK-α/β, IκB, and p65 subunit within 30 min. Moreover, the phosphorylation of p38 and c-Jun N-terminal protein kinase (JNK) in the mitogen-activated protein kinase (MAPK) pathway were also inhibited by hBD3 in HUVECs. In conclusion, hBD3 exerts anti-inflammatory and antioxidative effects in endothelial cells in response to TNF-α by inhibiting NF-κB and MAPK signaling.

Human β-defensin-3 inhibits migration of colon cancer cells via downregulation of metastasis-associated 1 family, member 2 expression.

The innate immune system plays an important role as the first line of defense against many types of microbes. Accumulating reports suggest that human β-defensins (hBDs) are expressed by and have certain roles in some cancer cells. In this study, we investigated the roles of hBD-3 in colon cancer cells. The expression of hBD-3 was examined by reverse transcriptase-polymerase chain reaction analysis of colon cancer cell lines and immunohistochemical staining of colon cancer tissues. The effect of hBD-3 on proliferation of colon cancer was assessed using the MTT assay and a real-time cell analyzer, and the effect of hBD-3 on the migration of colon cancer cells was also examined. The results showed that hBD-3 is not expressed in colon cancer cells but is produced by tumor-infiltrating monocytes. Migration of colon cancer cells was significantly inhibited by hBD-3 in a dose-dependent manner, although proliferation of colon cancer cells was not affected by administration of hBD-3. Moreover, reduced expression of metastasis-associated 1 family, member 2 (MTA2) mRNA in colon cancer cells was associated with exposure to hBD-3. In conclusion, progression of colon cancer was inhibited by hBD-3 in a paracrine fashion. Therefore, hBD-3 may be a potent new agent for treating colon cancer.

Antibacterial activity of human defensins on anaerobic intestinal bacterial species: a major role of HBD-3

Defensins are natural mucosal antimicrobial peptides and their broad spectrum activity against aerobic or facultative anaerobic bacteria has been well investigated. The aim of this study was to systematically examine the antibacterial activity of the small intestinal Paneth cell derived α-defensin HD5 and the major colonic β-defensins HBD-1–3 against strict anaerobic intestinal bacteria. The antibacterial activity was assessed with a flow cytometric assay employing a membrane potential sensitive dye as marker for loss of cell viability. The majority of the tested strains belonging to the dominant anaerobe genera of the gut, Bacteroides and Parabacteroides, were only minimally affected by the constitutively expressed defensins HD5 and HBD-1. The inducible defensin HBD-2 had a limited antibacterial effect, whereas the inducible HBD-3 exhibited potent activity against most strains. The effect of HBD-3 on Bacteroides sp. appeared to be dependent on the presence of oxygen. Bacteroides fragilis strains isolated from blood during bacteremia or from extraintestinal infections were more resistant to HBD-3 than strains from the physiological gut flora. Thus, defensin resistance is not only species- but also strain-specific and may be clinically relevant in the host–bacteria interaction influencing mucosal translocation and systemic infection.

Human β-defensin-3 induction inH pylori-infected gastric mucosal tissues

To examine human beta-defensin-3 (hBD-3) expression in inflamed gastric mucosal tissues or MKN45 gastric cancer cells with or without H. pylori infection for better understanding the innate immune response to H. pylori. We used reverse transcription-polymerase chain reactions and immunohistochemistry to examine hBD-3 expression in inflamed gastric mucosal tissues or MKN45 gastric cancer cells with or without H. pylori. Effects of hBD-3 against H. pylori were also evaluated. The mean mRNA expression of hBD-3 in H. pylori-positive specimens was significantly higher than that in H pylori-negative specimens (P = 0.0002, Mann-Whitney). In addition, unlike uninfected samples, 8 of 15 (53.33%) infected mucosal samples expressed hBD-3 protein. H. pylori dose-dependently induced mRNA expression of hBD-3 in MKN45 cells, an effect inhibited by adding anti-toll-like receptor (TLR)-4 antibody. HBD-3 protein completely inhibited H. pylori growth. Our results suggest that like hBD-2, hBD-3 may be involved in the pathophysiology of H. pylori-induced gastritis.