Expression Of Human Β-defensin Research Articles

Inhibition of porcine origin Klebsiella pneumoniae capsular polysaccharide and immune escape by BY3 compounded traditional Chinese medicine residue fermentation broth

Klebsiella pneumoniae (K. pneumoniae) is a gram-negative conditionally pathogenic bacterium that causes disease primarily in immunocompromised individuals. Recently, highly virulent K. pneumoniae strains have caused severe disease in healthy individuals, posing significant challenges to global infection control. Capsular polysaccharide (CPS), a major virulence determinant of K. pneumoniae, protects the bacteria from being killed by the host immune system, suggesting an urgent need for the development of drugs to prevent or treat K. pneumoniae infections. In this study, BY3 compounded traditional Chinese medicine residue (TCMR) was carried out using Lactobacillus rhamnosus as a fermentation strain, and BY3 compounded TCMR fermentation broth (BY3 fermentation broth) was obtained. The transcription of K. pneumoniae CPS-related biosynthesis genes after treatment with BY3 fermentation broth was detected using quantitative real-time polymerase chain reaction. The effects of BY3 fermentation broth on K. pneumoniae serum killing, macrophage phagocytosis, complement deposition and human β-defensin transcription were investigated. The therapeutic effect of BY3 fermentation broth on K. pneumoniae-infected mice was also observed, and the major active components of BY3 fermentation broth were analysed via LC‒MS analysis, network pharmacology, and molecular docking. The results showed that BY3 fermentation broth inhibited K. pneumoniae CPS production and downregulated transcription of CPS-related biosynthesis genes, which weakened bacterial resistance to serum killing and phagocytosis, while promoting bacterial surface complement C3 deposition and human β-defensin expression. BY3 fermentation broth demonstrated safety and therapeutic effects in vivo and in vitro, restoring body weight and visceral indices, significantly reducing the organ bacterial load and serum cytokine levels, and alleviating pathological organ damage in mice. In addition, three natural compounds—oleanolic acid, quercetin, and palmitoleic acid—were identified as the major active components in the BY3 fermentation broth. Therefore, BY3 fermentation broth may be a promising strategy for the prevention or treatment of K. pneumoniae infections.

Expression of Human β-defensin 2 (hBD-2) in Pichia Pastoris and Investigation of Its Binding Efficiency with ACE-2.

COVID-19 is a disease that have affected the entire world, and it continues to spread with new variants. A patient's innate immune system plays a critical role in the mild and severe transition of COVID-19. Antimicrobial peptides (AMPs), which are important components of the innate immune system, are potential molecules to fight pathogenic bacteria, fungi, and viruses. Human β-defensin 2 (hBD-2), a 41-amino-acid antimicrobial peptide, is one of the defensins inducibly expressed in the skin, lungs, and trachea in humans. In this study, it was aimed to investigate the interaction of hBD-2 produced recombinantly in Pichia pastoris with the human angiotensin-converting enzyme 2 (ACE-2) under in vitro conditions. First, hBD-2 was cloned in P. pastoris X-33 via the pPICZαA vector, a yeast expression platform, and its expression was confirmed by SDS-PAGE, western blotting, and qRT-PCR. Then, the interaction between recombinant hBD-2 and ACE-2 proteins was revealed by a pull-down assay. In light of these preliminary experiments, we suggest that the recombinantly produced hBD-2 may be protective against SARS-CoV-2 and be used as a supplement in treatment. However, current findings need to be supported by cell culture studies, toxicity analyses, and in vivo experiments.

Effects of Fluticasone Propionate on Klebsiella pneumoniae and Gram-Negative Bacteria Associated with Chronic Airway Disease.

Inhaled corticosteroids (ICS) are commonly prescribed first-line treatments for asthma and chronic obstructive pulmonary disease (COPD). Recent evidence has shown that ICS use is associated with changes in the airway microbiome, which may impact clinical outcomes such as potential increased risk for pneumonia in COPD. Although the immunomodulatory effects of corticosteroids are well appreciated, whether ICS could directly influence the behavior of respiratory tract bacteria has been unknown. In this pilot study we explored the effects of fluticasone proprionate, a commonly prescribed inhaled corticosteroid, on respiratory bacteria with an expanded focus on Klebsiella pneumoniae, a species previously implicated in fluticasone-associated pneumonia in COPD. We observed significant effects of fluticasone proprionate on growth responses of K. pneumoniae, as well as other bacterial species isolated from asthmatic patients. Fluticasone-exposed K. pneumoniae displayed altered expression of several bacterial genes and reduced the metabolic activity of bronchial epithelial cells and their expression of human β-defensin 2. Targeted assays identified a fluticasone metabolite from fluticasone-exposed K. pneumoniae cells, suggesting this species may be capable of metabolizing fluticasone proprionate. Collectively, these observations support the hypothesis that specific members of the airway microbiota possess the functional repertoire to respond to or potentially utilize corticosteroids in their microenvironment. These findings lay a foundation for novel research directions into the potential direct effects of ICS, often prescribed long term to patients, on the broader airway microbial community and on the behavior of specific microbial species implicated in asthma and COPD outcomes. IMPORTANCE Inhaled corticosteroids are widely prescribed for many respiratory diseases, including asthma and COPD. While they benefit many patients, corticosteroids can also have negative effects. Some patients do not improve with treatment and even experience adverse side effects. Recent studies have shown that inhaled corticosteroids can change the make-up of bacteria in the human respiratory tract. However, whether these medications can directly impact the behavior of such bacteria has been unknown. Here, we explored the effects of fluticasone propionate, a commonly prescribed inhaled corticosteroid, on Klebsiella pneumoniae and other airway bacteria of interest, including primary species isolated from adult asthma patients. We provide evidence of growth responses to direct fluticasone exposure in culture and further examined fluticasone's effects on K. pneumoniae, including gene expression changes and effects of fluticasone-exposed bacteria on airway cells. These findings indicate that members of the human airway bacterial community possess the functional ability to respond to corticosteroids, which may have implications for the heterogeneity of treatment response observed clinically.

Uncoupling melanogenesis from proliferation in epidermal melanocytes responding to stimulation with psoriasis-related proinflammatory cytokines

BackgroundFew studies have addressed the impact of the psoriasis-related proinflammatory cytokines on the proliferation and melanogenesis of melanocytes (MCs) in lesional psoriatic skin. ObjectiveWe investigated the effects of TNFα, IL17A, and IL8 on the proliferation and melanin synthesis of MCs. MethodsSkin specimens were biopsied from patients with psoriasis vulgaris at the active stage, or from the tail skin of Dct-LacZ mice with imiquimod (IMQ)-induced psoriasiform dermatitis. Cultured keratinocytes (KCs), MCs, and human skin explants were used in this study. The numbers of MCs were measured via β-galactosidase staining, EdU incorporation and HMB45 immunohistochemical staining. The expression of human β-defensin 3 (hBD3) in KCs was silenced by siRNA, the conditioned medium (CM) from siRNA-transfected KCs was used to treat MCs, then followed by αMSH stimulation. The melanogenesis-related genes were examined by using qRT-PCR and western blotting. ResultsThe increased number of MCs and decreased melanin content were highly relevant to the enhanced expression of IL8 and BD3 both in human psoriatic skin and in IMQ-treated mouse tail skin. IL8 expression in KCs and CXCR2 expression in MCs was significantly increased by IL17A and TNFα, the αMSH-induced upregulations of microphthalmia-associated transcription factor (MITF) and tyrosinase in MCs were abrogated by the CM from hBD3-unsilenced KCs, but not from hBD3-silenced KCs. ConclusionOur results suggest the roles of IL8-CXCR2 activation in promoting MC proliferation and of BD3 upregulation in reducing melanogenesis. These findings have been implicated in the underlying mechanism that active psoriasis prefers hypopigmentation despite chronic inflammation.

Anti-cancer Properties of Potential Probiotics and Their Cell-free Supernatants for the Prevention of Colorectal Cancer: an In Vitro Study.

This study aimed to characterize the anti-cancer properties of potential probiotics (Lacticaseibacillus paracasei SD1, Lacticaseibacillus rhamnosus SD4, Lacticaseibacillus rhamnosus SD11, and Lacticaseibacillus rhamnosus GG) and their cell-free supernatants (CFS) for the prevention of colorectal cancer (CRC), which including anti-bacterial and anti-inflammation activities against pathogens associated with CRC (Fusobacterium nucleatum, Porphyromonas gingivalis, ETEC, and Salmonella enterica). The expression of human β-defensin (2-4) and IL-10 after being stimulated with probiotics was also examined. In addition, anti-cancer activity of CFS and probiotic growth under intestinal conditions were determined. An in vitro study was conducted in the Caco-2 and HIEC-6 cells. Results showed that probiotic cells and their CFS displayed different antibacterial activity, and L. rhamnosus SD11 showed the strongest inhibition of the growth of pathogens. Additionally, both probiotic cell walls and their CFS suppressed pro-inflammatory cytokines after being stimulated with pathogens in Caco-2 and HIEC-6 cells. L. paracasei SD1 and L. rhamnosus SD11 showed significantly higher suppression levels than others and also both strains can stimulate highly expression of hBD (2-4) and IL-10. The CFS of L. paracasei SD1 and L. rhamnosus SD11 inhibited significantly high growth of Caco-2 cells but not much in HIEC-6 cells. Furthermore, all probiotics adhered to Caco-2 and HIEC-6 cells, and L. rhamnosus SD4 showed the highest adhesion to both cells. They could survive more than 70% in intestinal conditions. In conclusion, results indicate that potential probiotics tested exhibited various anti-cancer properties, which may be good candidates used as biotherapy for the prevention or to delay the progression of CRC.

Protective effect of inactivated blastoconidia in keratinocytes and human reconstituted epithelium against C. albicans infection.

Candida albicans is commensal yeast that colonizes skin and mucosa; however, it can become an opportunist pathogen by changing from blastoconidia (commensal form) into hypha (pathogenic form). Each form activates a different cytokines response in epithelial cells. Little is known about the commensal role of C. albicans in the innate immunity. This work studied whether stimulation with C. albicans blastoconidia induces protection in keratinocytes and/or in a reconstituted human epithelium (RHE) infected with C. albicans. For this, inactivated C. albicans blastoconidia was used to stimulate keratinocytes and RHE prior to infection with C. albicans. Blastoconidia induced different cytokine expression profiles; in the case of RHE it decreased interleukin (IL)-1β and IL-10 and increased IL-8, tumor necrosis factor α (TNF-α), and interferon γ (IFN-γ). A significant increase in the expression of human β-defensins (HBD) 2 and HBD3 was observed in blastoconidia stimulated keratinocytes and RHE, associated with impaired growth and viability of C. albicans. Additionally, blastoconidia stimulation decreased the expression of virulence factors in C. albicans that are associated with filamentation (EFG1, CPH1 and NRG1), adhesion (ALS5), and invasion (SAP2). Blastoconidia stimulated RHE was significantly less damaged by C. albicans invasion. These results show that the commensal form of C. albicans would exert a protective effect against self-infection.

Antibacterial responses of retinal Müller glia: production of antimicrobial peptides, oxidative burst and phagocytosis

BackgroundWe have previously shown that, in response to microbial infection, activated Müller glia secrete inflammatory cytokines/chemokines and exhibit antimicrobial properties. The aim of this study is to understand the mechanisms and the key components involved in this response.MethodsImmortalized human retinal Müller glia (MIO-M1 cells) were challenged with Staphylococcus (S) aureus, the leading cause of severe intraocular infection followed by RT2 profile PCR array analysis. The expression of human β-defensin 1 (HBD1), 2 (HBD2), 3 (HBD3), hepcidine and cathelicidin LL37 was checked by RT-PCR and quantified by Taqman® qPCR. The expression of AMPs was confirmed at protein level by dot-blot analysis. The production of ROS was measured by dicholoro-dihydro-fluorescein diacetate (DCFH-DA) staining by flow cytometry as well as fluorescence microscopy. The level of nitric oxide (NO) was measured by measuring a stable metabolite, nitrite using the Griess reagent. In vitro killing assay was performed by Live/Dead® BacLight™ staining as well as by dilution plating in suspension and adherent conditions following S. aureus infection. Phagocytosis was measured by CFU enumeration following infection.ResultsPCR array data showed that, in comparison to uninfected control cells, bacterial challenge significantly (> two-fold) induced the expression of 26 genes involved in cytokine/chemokine, antimicrobials, Toll-like receptor, apoptotic, and NF-κB signaling. RT-PCR analysis showed time-dependent increased expression of HBD1, HBD2, HBD3, LL-37, and hepcidin mRNA in bacteria-challenged Müller glia. The expression of these antimicrobial molecules was also increased at the protein level in the culture supernatant, as detected by dot-blot analysis. Additionally, the bacteria-stimulated Müller glia were found to produce reactive oxygen (ROS) and reactive nitrogen (RNS) species. In vitro, killing assays revealed that Müller glia exhibited bactericidal activity against S. aureus in both adherent and suspension cultures. Furthermore, our data demonstrated that Müller glia can phagocytize and kill the bacteria in a time-dependent manner.ConclusionsThese data suggest that retinal Müller glia behave like classical innate immune cells by producing a variety of antimicrobial molecules in response to bacterial challenge, suggesting their pivotal role in retinal innate defense.

Effect of narrow-band ultraviolet B on the expression of human β-defensin 2 in psoriatic patients, using immunohistochemistry

Effect of narrow-band ultraviolet B on the expression of human β-defensin 2 in psoriatic patients, using immunohistochemistry

β-defensins that bind CCR6: Blunting the permissiveness of Th17 cells to HIV infection (P4432)

Abstract HIV preferentially depletes IL-17-producing, CD4+ “T helper 17” (Th17) cells from the gut during the acute phase of infection. Th17 cells play a key role in mucosal barrier maintenance and protection against opportunistic infections commonly associated with HIV/AIDS. In response to IL-17, epithelial cells of mucosal barriers secrete β-defensins - a family of secreted, cationic peptides with potent broad-range antimicrobial activity against bacteria, fungi, and viruses including HIV. Our laboratory has shown that the expression of human β-defensin 2 (hBD2) is markedly decreased in the oral mucosa of HIV+ subjects, and that β-defensins, in addition to direct antimicrobial activity, upregulate the HIV restriction factor APOBEC3G via the chemokine receptor CCR6, which is expressed on Th17 cells. In order to characterize the effects of HIV infection on the Th17 subset and determine if β-defensins can protect Th17 cells from HIV infection, activated human primary CD4+ T cells are infected and/or treated with β-defensin, then characterized by flow cytometry. Our results show that IL-17A+ cells from peripheral blood are highly permissive to HIV, and are preferentially lost during infection. In addition, our model suggests that Th17-polarizing cytokines enhance HIV infection, and that β-defensins can protect these cells from infection. Our studies of the factors contributing to protection of Th17 cells may yield new therapeutic targets to protect the Th17 compartment.

Effect of allergic rhinitis on the expression of human β-defensin 2 in tonsils

BackgroundHuman β-defensins (HBDs) are a newly identified family of antimicrobial peptides that are expressed by epithelia on mucosal surfaces. Exposure of airway epithelial cells to TH2-type cytokines results in a significant decrease in the antimicrobial activity of the cells. ObjectiveTo investigate the effect of allergic rhinitis on the expression of HBD-2 in tonsils and adenoids. MethodsPalatine tonsils and adenoids were obtained from 30 patients with no history of recurrent tonsillitis. The patients were divided into 2 groups: allergic rhinitis and nonallergic rhinitis groups. Real-time polymerase chain reaction analysis was used to measure messenger RNA (mRNA) levels of HBD-2 mRNA in tonsil and adenoid tissue samples from the 2 patient groups. Immunofluorescent staining and enzyme-linked immunosorbent assay (ELISA) were used to evaluate the expression of HBD-2 protein in tonsil and adenoid tissues. The concentration of the cytokines interleukin (IL) 4, IL-5, and interferon γ (IFN-γ) in tissue homogenates was measured by ELISA. ResultsImmunofluorescent staining data demonstrated the expression of HBD-2 protein in the surface epithelia of tonsils, and a marked difference in the staining intensity was observed the between 2 groups. HBD-2 mRNA and protein levels in the tonsils were significantly lower in the allergic rhinitis group than that in the nonallergic rhinitis group (P = .03 and P = .04, respectively). IL-5 and IFN-γ were not detected, and no significant difference was found in IL-4 concentrations in tonsil homogenates between the 2 groups. ConclusionAllergic rhinitis suppresses HBD-2, an epithelial antimicrobial peptide, in the tonsils.

Inducible expression of human β-defensin 2 by Chlamydophila pneumoniae in brain capillary endothelial cells

Defensins are an important family of natural antimicrobial peptides. Chlamydophila pneumoniae, a common cause of acute respiratory infection, has a tendency to cause persistent inflammatory diseases such as atherosclerosis, which may lead to cardiovascular disease or stroke. As endothelial cells are related to the physiopathology of stroke, the effects of invitro C. pneumoniae infection on the expression of human β-defensin 2 (HBD-2) in brain capillary endothelial cells (BB19) was investigated. A time-dependent increase in HBD-2 mRNA was observed by means of real-time reverse transcription PCR (RT-PCR) in BB19 cells following C. pneumoniae infection, with a maximum increase at 24 h. A gradual induction of HBD-2 protein in the C. pneumoniae-infected endothelial cells was detected by immunoblotting. Immunofluorescence revealed the staining of HBD-2 in the cytoplasm of endothelial cells following C. pneumoniae infection. The secretion of HBD-2 (confirmed by ELISA) was significantly elevated 24 h after C. pneumoniae infection. These novel results indicate that HBD-2 is expressed and produced in the human brain capillary endothelial cells upon infection with C. pneumoniae, and provide evidence that HBD-2 plays a role in the early immune responses to C. pneumoniae and probably in the immunopathogenesis of atherosclerosis.

403 Regulation of Human β-Defensin Expression by a Disintegrin and Metalloprotease Family of Membrane Glycoproteins (ADAM) in Candida Esophagitis

403 Regulation of Human β-Defensin Expression by a Disintegrin and Metalloprotease Family of Membrane Glycoproteins (ADAM) in Candida Esophagitis

Differential modulation of human β-defensins expression in human gingival epithelia by Porphyromonas gingivalis lipopolysaccharide with tetra- and penta-acylated lipid A structures

Porphyromonas gingivalis lipopolysaccharide (LPS) is a crucial virulence factor strongly involved in the development of chronic periodontitis. It displays a significant amount of lipid A structural heterogeneity, containing both tetra- (LPS(1435/1449) ) and penta-acylated (LPS( 1690)) lipid A structures with opposing effects on E-selectin expression in human endothelial cells. Little is known about how these two isoforms of P. gingivalis LPS could differentially affect host innate immune responses in human gingival epithelia. The present study compares the modulatory effects of P. gingivalis LPS(1435/1449) and LPS(1690) on the expression of human beta-defensins (hBDs) in the reconstituted human gingival epithelium, and examines the involvements of a panel of pattern recognition receptors in the modulatory effects concerned. It is shown that hBD-1, hBD-2 and hBD-3 mRNAs are significantly up-regulated by P. gingivalis LPS(1690), but down-regulated by P. gingivalis LPS( 1435/1449). Toll-like receptor (TLR) 2 and CD14 mRNAs are also differentially regulated, and the modulation of hBD-2 expression may be through the co-operation of both TLR2 and TLR4. This study suggests that P. gingivalis LPS with different lipid A structures could differentially modulate host innate immune responses in human gingival epithelia, which may be a hitherto undescribed novel pathogenic mechanism of P. gingivalis in periodontal pathogenesis.

Corrigendum

Oral DiseasesVolume 15, Issue 2 p. 183-183 Free Access Corrigendum This article corrects the following: Expression of human β-defensin -1, -2, and -3 in non-inflamed pseudocyst, mucoceles MK Frederic, T Yamaai, N Mizukawa, Y Kaneda, N Katase, M Gunduz, H Nagatsuka, T Sugahara, Volume 14Issue 7Oral Diseases pages: 652-657 First Published online: July 8, 2008 First published: 05 February 2009 https://doi.org/10.1111/j.1601-0825.2009.01519.xAboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat In (1), the following error was published on page 652. OnlineOpen: This article is available free online at http://www.blackwell-synergy.com The article is not OnlineOpen and should have been just a regular article. The authors would like to apologize for this error. Reference MK Frederic, Yamaai T, Mizukawa N, Kaneda Y, Katase N, Gunduz M, Nagatsuka H, Sugahara T (2008). Expression of human β-defensin -1, -2, and -3 in non-inflamed pseudocyst, mucoceles. Oral Dis 7: 652– 657. Web of Science®Google Scholar Volume15, Issue2March 2009Pages 183-183 ReferencesRelatedInformation

Expression of human β-defensin 1 is regulated via c-Myc and the biological clock

Human β-defensin 1 (hBD-1) is an important antibacterial polypeptide whose expression is not induced by infection or inflammation. Our objective was to study the regulation of hBD-1 expression. Recently, we found that albumin up-regulated hBD-1 as well as c-Myc expression, suggesting that c-Myc may regulate hBD-1 expression via a non-inflammatory pathway. Direct evidence for the involvement of c-Myc was achieved by the inhibition of hBD-1 expression in the presence of a specific c-Myc inhibitor. Since both c-Myc and CLOCK:BMAL1 heterodimer, the complex of the core clock mechanism, bind to E-box (5′-CACGTG-3′) and E-box-like sequences to activate transcription, we studied whether hBD-1 expression was also regulated by the biological clock. Synchronization of HCT-116 cells by dexamethasone showed oscillation of hBD-1 and c-myc mRNA indicating that both are clock-controlled output genes. Using transfections and luciferase reporter assays in human embryonic kidney (HEK-293) cells, we found that hBD-1 promoter was induced by CLOCK:BMAL1 co-expression. hBD-1 promoter truncation and mutagenesis analyses revealed that the distal E-box-like binding sequence was the target of both CLOCK:BMAL1 and c-Myc for hBD-1 expression. This activation was abolished when CRY1 was co-expressed in these cells. Thus, hBD-1 expression is mediated by c-Myc and the CLOCK:BMAL1 heterodimer, whereas CRY1 expression represses this complex. These changes in hBD-1 levels lead to its circadian oscillation.

Expression of human β-defensins in patients with mycosis fungoides

The human beta-defensins (hBDs) are peptides with a strong antimicrobial activity. Patients with atopic dermatitis (AD) and mycosis fungoides (MF) are prone to skin infections. We aimed to investigate the mRNA expression of hBDs in lesional and non-lesional skin of MF patients, and to compare the data with hBD levels found in AD patients and healthy controls. In this prospective pilot study, 13 patients with MF were recruited. Punch biopsies were harvested from the centre of the tumour (lesional) as well as a healthy skin site (non-lesional controls). In addition to the specimens of MF patients, skin samples (healthy controls) were obtained from healthy subjects (n = 15) and patients with acute AD (n = 14). In order to detect mRNA of hBDs, we performed quantitative real-time reverse transcriptase polymerase chain reaction. As compared to healthy controls, skin of patients with MF (non-lesional and lesional) and AD patients showed significantly lower hBD-1 mRNA expression and significantly higher hBD-2 and hBD-3 mRNA expression. HBD-1 mRNA levels of lesional skin were significantly lower than those of non-lesional skin. By contrast, significantly increased hBD-2 and hBD-3 mRNA expression was found in lesional skin of MF patients when compared to non-lesional skin. HBD mRNA expression in lesional skin of MF patients did not significantly differ from hBD expression that was observed in AD lesions. We observed an identical pattern of hBD expression in MD and AD suggesting a common regulatory mechanism that might mainly be driven by T helper 2 lymphocytes.

Diesel exhaust particles increase IL-1β-induced human β-defensin expression via NF-κB-mediated pathway in human lung epithelial cells

BackgroundHuman β-defensin (hBD)-2, antimicrobial peptide primarily induced in epithelial cells, is a key factor in the innate immune response of the respiratory tract. Several studies showed increased defensin levels in both inflammatory lung diseases, such as cystic fibrosis, diffuse panbronchiolitis, idiopathic pulmonary fibrosis and acute respiratory distress syndrome, and infectious diseases. Recently, epidemiologic studies have demonstrated acute and serious adverse effects of particulate air pollution on respiratory health, especially in people with pre-existing inflammatory lung disease. To elucidate the effect of diesel exhaust particles (DEP) on pulmonary innate immune response, we investigated the hBD-2 and interleukin-8 (IL-8) expression to DEP exposure in interleukin-1 beta (IL-1β)-stimulated A549 cells.ResultsIL-1β markedly up-regulated the hBD-2 promoter activity, and the subsequent DEP exposure increased dose-dependently the expression of hBD-2 and inflammatory cytokine IL-8 at the transcriptional level. In addition, DEP further induced the NF-κB activation in IL-1β-stimulated A549 cells more rapidly than in unstimulated control cells, which was showed by nuclear translocation of p65 NF-κB and degradation of IκB-α. The experiment using two NF-κB inhibitors, PDTC and MG132, confirmed that this increase of hBD-2 expression following DEP exposure was regulated through NF-κB-mediated pathway.ConclusionThese results demonstrated that DEP exposure increases the expression of antimicrobial peptide and inflammatory cytokine at the transcriptional level in IL-1β-primed A549 epithelial cells and suggested that the increase is mediated at least partially through NF-κB activation. Therefore, DEP exposure may contribute to enhance the airway-responsiveness especially on the patients suffering from chronic respiratory disease.

Intracellular calcium in signaling human beta-defensin-2 expression in oral epithelial cells.

Expression of human beta-defensins is correlated with differentiation in the oral epithelium, consistent with their function as part of the epithelial antimicrobial barrier. Because calcium is a known regulator of epithelial differentiation, we tested the hypothesis that calcium concentration mediates beta-defensin expression. Gingival epithelial cells were cultured in medium containing low calcium concentration (0.03 mM), then either changed to high extracellular calcium concentrations or stimulated with thapsigargin to release intracellular calcium stores in the presence or absence of BAPTA-AM, a calcium chelator. Human beta-defensin-2 (hBD-2) mRNA expression was rapidly induced by thapsigargin, and more slowly induced by high extracellular calcium. Induction of hBD-2 peptide was confirmed by immunofluorescence. BAPTA-AM inhibited hBD-2 induction by both thapsigargin and calcium in a dose-dependent fashion. In addition, BAPTA-AM inhibited hBD-2 induction by a bacterial stimulant. Collectively, these findings demonstrate that intracellular calcium is a critical mediator of hBD-2 expression. Abbreviations used in this study are: BAPTA-AM, 1,2-bis(2-aminophenoxy)-ethane-N,N,N',N'-tetra-acetic acid tetrakis (acetoxymethyl ester); DMSO, dimethylsulfoxide; F. nucleatum, Fusobacterium nucleatum; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; HBDs, human beta-defensins; HGECs, human gingival epithelial cells; MAP, mitogen-activated protein; and RT-PCR, reverse-transcriptase/polymerase chain-reaction.

Expression of human β-defensin 2 (hBD-2) inHelicobacter pylori induced gastritis: antibacterial effect of hBD-2 against Helicobacter pylori

BACKGROUNDHuman β-defensin 2 (hBD-2) plays a role in the innate defence system at mucosal surfaces. Colonisation of Helicobacter pylori in the stomach is an important pathological factor in gastrointestinal illnesses,...