Concentrations of α-and β-defensins in gastric juice of patients with various gastroduodenal diseases

AIM: To determine the concentration of α-and β-defensins in gastric juice of patients with various gastroduodenal diseases. METHODS: Concentrations of human neutrophil peptides (HNPs) 1-3, the major forms of α-defensins, and human β-defensin (HBD)-1and HBD-2were measured by radioimmunoassay in plasma and gastric juice of 84 subjects, consisting of 54 Helicobacter pylori-infected and 30 uninfected subjects. They included 33 patients with chronic gastritis (CG), 12 with gastric ulcer (GU), 11 with duodenal ulcer (DU), 11 with benign gastric polyp (BGP) and 16 with normal mucosa (N group) on upper endoscopy. Plasma pepsinogen Ⅰ and Ⅱ levels, biomarkers for gastric mucosal inflammation and atrophy, were also measured. RESULTS: Gastric juice HNPs 1-3 levels in patients with CG, GU and BGP were significantly higher than those in patients with DU and N. Gastric juice HBD-2 concentrations in patients with CG and GU were significantly higher than those in the N group, but were significantly lower in DU patients than in GU patients. Gastric juice HBD-1 levels and plasma levels of these peptides were similar in the patient groups. Concentrations of gastric juice HNPs 1-3 and HBD-2 of in H pylori-infected patients were significantly different from those in uninfected subjects. HNPs 1-3 concentrations in gastric juice correlated negatively with plasma pepsinogen I levels and Ⅰ/Ⅱ ratios. HBD-2 levels in gastric juice correlated positively and negatively with plasma pepsinogen Ⅱ concentrations and Ⅰ/Ⅱratios, respectively. CONCLUSION: HNPs 1-3 and HBD-2 levels in gastric juice are diverse among various gastrointestinal diseases, reflecting the inflammatory and atrophic events of the background gastric mucosa affected by H pylori.

β-defensins and the epididymis： contrasting influences of prenatal, postnatal, and adult scenarios

β-defensins are components of host defense, with antimicrobial and pleiotropic immuno-modulatory properties. Research over the last 15 years has demonstrated abundant expression of a variety of β-defensins in the postnatal epididymis of different species. A gradient of region- and cell-specific expression of these proteins is observed in the epithelium of the postnatal epididymis. Their secretion into the luminal fluid and binding to spermatozoa as they travel along the epididymis has suggested their involvement in reproduction-specific tasks. Therefore, continuous attention has been given to various β-defensins for their role in sperm function and fertility. Although β-defensins are largely dependent on androgens, the underlying mechanisms regulating their expression and function in the epididymis are not well understood. Recent investigation has pointed out to a new and interesting scenario where β-defensins emerge with a different expression pattern in the Wolffian duct, the embryonic precursor of the epididymis, as opposed to the adult epididymis, thereby redefining the concept concerning the multifunctional roles of β-defensins in the developing epididymis. In this review, we summarize some current views of β-defensins in the epididymis highlighting our most recent data and speculations on their role in the developing epididymis during the prenatal-to-postnatal transition, bringing attention to the many unanswered questions in this research area that may contribute to a better understanding of epididymal biology and male fertility.

Relevance of α-defensins(HNP1-3) and defensin β-1 in diabetes

AIM: To investigate the genetic background of human defensin expression in type 1 and 2 diabetes.

Protective eff ect and mechanism of nanoantimicrobial peptide ND-C14 against Streptococcus pneumoniae infection

BACKGROUND:Streptococcus pneumoniae(S.pneumoniae)is a common pathogen that causes bacterial pneumonia.However,with increasing bacterial resistance,there is an urgent need to develop new drugs to treat S.pneumoniae infections.Nanodefensin with a 14-carbon saturated fatty acid(ND-C14)is a novel nanoantimicrobial peptide designed by modifying myristic acid at the C-terminus of humanα-defensin 5(HD5)via an amide bond.However,it is unclear whether ND-C14 is effective against lung infections caused by S.pneumoniae.METHODS:In vitro,three groups were established,including the control group,and the HD5 and ND-C14 treatment groups.A virtual colony-count assay was used to evaluate the antibacterial activity of HD5 and ND-C14 against S.pneumoniae.The morphological changes of S.pneumoniae treated with HD5 or ND-C14 were observed by scanning electron microscopy.In vivo,mice were divided into sham,vehicle,and ND-C14 treatment groups.Mice in the sham group were treated with 25μL of phosphate-buffered saline(PBS).Mice in the vehicle and ND-C14 treatment groups were treated with intratracheal instillation of 25μL of bacterial suspension with 2×108 CFU/mL(total bacterial count:5×10^(6) CFU),and then the mice were given 25μL PBS or intratracheally injected with 25μL of ND-C14(including 20μg or 50μg),respectively.Survival rates were evaluated in the vehicle and ND-C14 treatment groups.Bacterial burden in the blood and bronchoalveolar lavage fluid were counted.The lung histology of the mice was assessed.A propidium iodide uptake assay was used to clarify the destructive eff ect of ND-C14 against S.pneumoniae.RESULTS:Compared with HD5,ND-C14 had a better bactericidal eff ect against S.pneumoniae because of its stronger ability to destroy the membrane structure of S.pneumoniae in vitro.In vivo,ND-C14 significantly delayed the death time and improved the survival rate of mice infected with S.pneumoniae.ND-C14 reduced bacterial burden and lung tissue injury.Moreover,ND-C14 had a membrane permeation eff ect on S.pneumoniae,and its destructive ability increased with increasing ND-C14 concentration.CONCLUSION:The ND-C14 may improve bactericidal eff ects on S.pneumoniae both in vitro and in vivo.

High concentrations of human β-defensin 2 in gastric juice of patients with Helicobacter pylori infection

MIA： Human β-defensin （HBD）-1 and HBD-2 are endogenous antimicrobial peptides. Unlike HBD-1, the HBD-2 expression is augmented by Helicobacter pylori （H pylon）. We sought to determine HBD-1 and HBD-2 concentrations in gastric juice during Hpylori infection. METHODS： HBD-1 and HBD-2 concentrations were measured by radioimmunoassay in plasma and gastric juice of 49 Hpylori-infected and 33 uninfected subjects and before and after anti-H pyloritreatment in,13 patients with Hpylori-associated gastritis. Interleukin （IL）-1β and IL-8 concentrations in gastric juice were measured by enzyme-linked immunosorbent assay （ELISA）. Histological grades of gastritis were determined using two biopsy specimens taken from the antrum and corpus. Reverse phase high performance liquid chromatography （RP-HPLC） was used to identify HBD-2. RESULTS： HBD-2 concentrations in gastric juice, but not in plasma, were significantly higher in Hpylori-positive than -negative subjects, albeit the post-treatment levels were unchanged. Immunoreactivity for HBD-2 was exclusively identified in Hpylori-infected mucosa by RPHPLC. HBD-2 concentrations in gastric juice correlated with histological degree of neutrophil and mononuclear cell infiltration in the corpus. IL-1β levels correlated with those of IL-8, but not HBD-2. Plasma and gastric juice HBD-1 concentrations were similar in H pylori-infected and uninfected subjects. CONCLUSION： Our results place the β-defensins, especiallyHBD-2, in the front line of innate immune defence. Moreover, HBD-2 may be involved in the pathogenesis of Hpylori-associated gastritis, possibly through its function as immune and inflammatory mediator.

Human β-defensin 2 enhances IL-1β production and pyroptosis through P2X7-mediated NLRP3 expression in macrophages

Periodontal disease is the leading cause of tooth loss,which is also a high-risk factor for other diseases including oral cancer and cardiovascular disease.Periodontitis is one of the most common type of periodontal diseases.Interleukin-1β(IL-1β)plays a key role in the pathogenesis of periodontitis.However,the mechanism how IL-1βis produced during periodontitis is still unclear.In the present study,we found that humanβ-defensin 2(hBD2)enhances IL-1βproduction through an LPS-primed human acute monocytic leukemia(THP-1)macrophage model.Inhibition of P2X purinoceptor 7(P2X7)reduced hBD2-enhanced IL-1βproduction.Incubation of LPS-primed THP-1 macrophages with potassium chloride also suppressed hBD2-enhanced IL-1βproduction.Silence of inflammasome adaptor Nod-like receptor family pyrin domain containing 3(NLRP3)led to reduced hBD2-enhanced IL-1βproduction.Likewise,inhibition of caspase-1 also resulted in the decrease of IL-1β.Moreover,an ethidium bromide uptake test indicated that hBD2-activated caspase-1 mediated pyroptotic pore formation.Subsequent lactate dehydrogenase detection and flow cytometric analysis indicated that hBD2 also induced pyroptosis.In brief,these findings illustrated not only the mechanism of hBD2 in enhancing the inflammatory response,but also provided novel therapeutic targets for periodontitis.

Comment on “Effect of biofilm formation by clinical isolates of Helicobacter pylori on the efflux-mediated resistance to commonly used antibiotics”

Attaran et al[1] have recently shown that decreased susceptibility of established Helicobacter pylori(H. pylori) biofilms to specific antibiotics,was associated with the overtly enhanced transcription of two efflux pump genes,hp1165 and hef A,involved in specific resistance to tetracycline and multiple antibiotics,respectively. Apart from antibiotic exposure,secretion of multiple antimicrobial peptides,such as human β-defensins(hβDs),by the gastric epithelium upon Hp challenge,may act as early triggering events that positively impact biofilm formation and thus,antibiotic resistance. In this regard,we undertook genomic transcriptional studies using Hp 26695 strain following exposure to sublethal,similar to those present in the gastric niche,concentrations of hβDs in an attempt to provide preliminary data regarding possible mechanisms of immune evasion and selective sensitivity of Hp. Our preliminary results indicate that hβD exposure ignites a rapid response that is largely due to the activation of several,possibly interconnected transcriptional regulatory networks – origons-that ultimately coordinate cellular processes needed to maintain homeostasis and successful adaptation of the bacterium in the gastric environment. In addition,we have shown that both antibiotic and hβD resistance are mediated by dedicated periplasmic transporters,including the aforementioned efflux pump genes hp1165 and hef A,involved in active export of antibiotics from the cell membrane and/or,as recently suggested,substrate sensing and signalling. Furthermore,itappears that sublethal doses of hβDs may enhance biofilm formation by the sustained expression of,mainly,quorum sensing-related genes. In conclusion,we provide additional data regarding the role of specific innate immune molecules in antibiotic cross-resistance mechanisms that may deepen our understanding in the context of the development of novel eradication regimens.

Effect of Different Concentrations of Lipopolysaccharide on Expression of NF-κB and LAP in Mammary Epithelial Cells of Dairy Cow

The paper was to study the effects of different concentrations of lipopelysaccharide （LPS） on expression of nuclear factor Kappa B （NF-κB） and lingual antimicrobial peptide （LAP） gene in mammary epithelial ceils of dairy cow. The mammary epithelial ceils of dairy cow were stimulated by different concentrations （50, 100,200,400 and 800 ng/mL） of LPS. The total RNA of cells was extracted after stimulation for 2, 4, 8, 16, 24, 48 and 72 h, respectively, and the mRNA expression levels of NF-κB P65 and LAP were evaluated by real-time quantitative PCR. The results showed that the expression of NF-κB P65 and LAP mRNA treated with 400 ng/mL LPS for 72 h were the highest compared to the control group （ P 〈0.01 ）. The result confirmed that the expression activity of NF-κB was enhanced in inflammatory effects of inammary epithelial cells induced by LPS, which regulated the expression of defense gene LAP, with certain dose and time effects.

DICER1 regulates antibacterial function of epididymis by modulating transcription of p-defensins

DICER1 is a key enzyme responsible for the maturation of microRNAs. Recent evidences suggested that DICER1 and microRNAs expressed in epididymis were involved in the control of male fertility. However, the exact mechanism remains to be elucidated. Here, we created a mouse line by targeted disruption of Dicerl gene in the principal cells of distal caput epididymis. Our data indicated that a set of β-defensin genes were downregulated by DICER1 rather than by microRNAs. Moreover, DICER1 was significantly enriched in the promoter of β-defensin gene and controlled transcription. Besides, the antibacterial ability of the adult epididymis significantly declined upon Dicerl deletion both in vitro and in vivo. And a higher incidence of reproductive defect was observed in middle-aged Dicerl^-|- males. These results suggest that DICER1 plays an important role in transcription of β-defensin genes, which are associated with the natural antibacterial properties in a microRNA-independent manner, and further impacts the male fertility.

Isoleucine, an Essential Amino Acid, Induces the Expression of Human <i>β</i>Defensin 2 through the Activation of the G-Protein Coupled Receptor-ERK Pathway in the Intestinal Epithelia

Anti-microbial peptides are essential for the intestinal innate immunity that protects the intestinal epithelia from attacks by foreign pathogens. Human β-defensin (HBD) is one of the pivotal anti-microbial peptides that are expressed in the colonic epithelia. This study investigated the effect and the signaling mechanism of inducible β-defensin HBD2 by an essential amino acid, isoleucine (Ile) in colonic epithelial cells. Here we examined the expression level of HBD2 on induction of Ile in epithelial cells, and checked this pathway. HBD2 mRNA was induced by co-incubation with IL-1α and Ile in Caco2 cells, but not by Ile alone. An inhibitor of either ERK or Gi, a subunit of G-proteins, reduced the induction of HBD2 mRNA by Ile. The treatment with Ile also increased the intracellular calcium ion concentration, thus suggesting that the GPCR and ERK signaling pathway mediate the effects of Ile. These results indicate that an essential amino acid, Ile, enhances the expression of an inducible β-defensin, namely HBD2, by IL-1α through the activation of GPCRs and ERK signaling pathway. The administration of Ile may therefore represent a possible option to safely treat intestinal inflammation.

HBD-2在尖锐湿疣患者皮损组织中表达的临床意义

尖锐湿疣（condyloma acuminatum，CA）是人乳头状病毒感染引起的性传播疾病之一，主要发生于外生殖器及肛门附近，主要病理表现为外生殖器、肛门区域皮肤黏膜的良性增生。近年来随着人们性观念的开放，包括CA在内的性传播疾病明显增多。复发率高，难以彻底根除是CA的主要特点，β-防御素-2（hunman β-defensin2，HBD-2）是广存在于人类皮肤和黏膜的抗菌肽分子，具有调节免疫和抗多种病原微生物的作用。作者通过测定30例CA病变组织中HBD-2表达，并与银屑病患者和健康对照组比较，以探讨HBD-2在CA发病和转归中的作用。报道如下。

Construction and Identification of Mammary Gland-specific Expression Vector of Bovine Tracheal Antimicrobial Peptide (TAP)

[ Objective] This study aimed to construct nmnmm_ry gland-specific expression vector of bovine tracheal antimicrobial peptide （TAP） gene. [ Method] TAP gene of dairy cattle was amplified from the mammary gland tissue by RT-PCR using a pair of primers which were designed according to bovine TAP cDNA se- quence （NM_174776） in GenBank, and then cloned into pMD19-T Simple vector for sequencing. The recombinant plasmid was digested using EcoRI and KpnI, the target gene fragment was recovered and inserted into general mammary gland-specific expression vector pBLG-EGFP harboring enhanced green fluorescent protein （ EGFP）, and transfected into bovine mammary epithelial cells （bMEC）, COS-7 cells and lactating rabbit mmmnary gland tissue by lipofectin transfection. The ex- pression of green fluorescent protein in transfected cells was detected under fluorescence microscopy, and the expression of TAP mRNA in rabbit mammary gland tis- sue was detected by semi-quantity RT-PCR. [ Result] The constructed mammary gland-specific expression vector pBLG-EGFP-TAP specifically expressed EGFP in transfected bMECs. In addition, semi-quantitative RT-PCR result showed that the expression level of TAP mRNA in rabbit mammary gland tissue was significantly enhanced after transfeeted with pBLG-EGFP-TAP. [ Conclusion] The mammary gland-specific expression vector pBLG-EGFP-TAP was successfully constructed, which provided important materials for further investigation of expression characteristics of TAP gene and prevention of bovine mastitis by using genetic engineering technology.

Novel phenotype of mouse spermatozoa following deletion of nine β-defensin genes

β-defensin peptides are a large family of antimicrobial peptides. Although they kill microbes in vitroand interact with immune cells, the precise role of these genes in vivo remains uncertain. Despite their inducible presence at mucosal surfaces, their main site of expression is the epididymis. Recent evidence suggests that a major function of these peptides is in sperm maturation. In addition to previous work suggesting this, work at the MRC Human Genetics Unit, Edinburgh, has shown that homozygous deletion of a cluster of nine β-defensin genes in the mouse results in profound male sterility. The spermatozoa derived from the mutants had reduced motility and increased fragility. Epididymal spermatozoa isolated from the cauda region of the homozygous mutants demonstrated precocious capacitation and increased spontaneous acrosome reactions compared with those from wild-types. Despite this, these mutant spermatozoa had reduced ability to bind to the zona pellucida of oocytes. Ultrastructural examination revealed a disintegration of the microtubule structure of mutant-derived spermatozoa isolated from the epididymal cauda region, but not from the caput. Consistent with premature acrosome reaction and hyperactivation, spermatozoa from mutant animals had significantly increased intracellular calcium content. This work demonstrates that in vivo β-defensins are essential for successful sperm maturation, and that their disruption alters intracellular calcium levels, which most likely leads to premature activation and spontaneous acrosome reactions that result in hyperactivation and loss of microtubule structure of the axoneme. Determining which of the nine genes are responsible for the phenotype and the relevance to human sperm function is important for future work on male infertility.

Human β-defensin-2 Enhances Anti-tumor Efficacy of Survivin-based Broad-spectrum DNA Vaccine in Mouse Tumor Model

Objective:Malignant tumors greatly endanger and affect the quality of human life.Among antitumor biotherapy strategies,DNA vaccines hold promise in part because of their unique advantages.In this study,an effective broad-spectrum antitumor DNA vaccine expressing human survivin T34A dominant-negative mutant fused with humanβ-defensin-2(HBD2)was investigated.Methods:The expression profiles of genes of interest were examined using western blotting,reverse transcription-polymerase chain reaction(RT-PCR),and enzyme-linked immunosorbent assay(ELISA)in vitro.The immune function of the fusion gene vaccine(FGV)was assessed in BALB/c mice,which included detection of serum antibody,spleen lymphocyte proliferation,interferon-gamma(IFN-γ)secretion,and lactate dehydrogenase(LDH)release.In vivo antitumor effects of FGV were examined in a mouse breast cancer(4T1)model,whereas in vitro effects were assessed using tumor cells derived from different origins.Caspase-3activity in tumor cells was also assessed after vaccine transfection.Results:The FGV triggered humoral as well as cellular immune responses against survivin.It exhibited more potent inhibition of tumor growth as well as prolonged the survival of immunized mice compared to mice immunized with only either survivin T34A or HBD2 vaccines.In addition,FGV displayed stronger cytotoxicity against tumor cells derived from different origins compared to the other vaccines and facilitated increased caspase-3 activity in transfected tumor cells.Conclusion:The novel DNA vaccine consisting of a fusion of the universal tumor antigen survivin T34A mutant with molecular adjuvant HBD2generates enhanced broad-spectrum antitumor efficacy against cancers derived from various origins.

A tetrahedral framework nucleic acid based multifunctional nanocapsule for tumor prophylactic mRNA vaccination

Synthetic antigen-encoding mRNA plays an increasingly significant role in tumor vaccine technology owing to its antigen-specific immune-activation. However, its immune efficacy is challenged by inferior delivery efficiency and demand for suitable adjuvants. Here, we develop a novel mRNA nanovaccine based on a multifunctional nanocapsule, which is a dual-adjuvant formulation composed of cytosine-phosphateguanine motifs loaded tetrahedral framework nucleic acid(CpG-tFNA) and an immunopeptide murine β-defensin 2(mDF2β). This m RNA nanovaccine successfully achieves intracellular delivery, antigen expression and presentation of dendritic cells, and proliferation of antigen-specific T cells. In a tumor prophylactic vaccination model, it exerts an excellent inhibitory effect on lymphoma occurrence through cellular immunity. This mRNA nanovaccine has promising prophylactic applications in tumors and many other diseases.

DEFB126 polymorphisms and association with idiopathic asthenozoospermia in China

Idiopathic asthenozoospermia,a common factor in male infertility,is characterized by altered sperm motility function in fresh ejaculate.Although theβ-defensin 126(DEFB126)protein is associated with asthenozoospermia,DEFB126 gene polymorphisms have not been extensively studied.Therefore,the association between DEFB126 gene polymorphisms and asthenozoospermia requires further investigation.Screening was performed by semen analysis,karyotype analysis,and Y microdeletion detection,and 102 fertile men and 106 men with asthenozoospermia in Chengdu,China,were selected for DEFB126 gene sequence analyses.Seven nucleotide mutations and two nucleotide deletions in the DEFB126 gene were detected.rs11467417(317-318 del/del),rs11467497(163-166 wt/del),c.152T>C,and c.227A>G were significantly different between the control and asthenozoospermia groups,likely representing high-risk genetic factors for asthenozoospermia among males.DEFB126 expression was not observed in sperm with rs11467497 homozygous deletion and was unstable in sperm with rs11467417 homozygous deletion.The rs11467497 four-nucleotide deletion leads to truncation of DEFB126 at the carboxy-terminus,and the rs11467417 binucleotide deletion produces a non-stop messenger RNA(mRNA).The above deletions may be responsible for male hypofertility and infertility by reducing DEFB126 affinity to sperm surfaces.Based on in silico analysis,the amino acids 51M and 76K are located in the highly conserved domain;c.152T>C(M51T)and c.227A>G(K76R)are predicted to be damaging and capable of changing alternative splice,structural and posttranslational modification sites of the RNA,as well as the secondary structure,structural stability,and hydrophobicity of the protein,suggesting that these mutations are associated with asthenozoospermia.