The RNA helicase Dhx15 mediates Wnt-induced antimicrobial protein expression in Paneth cells.

RNA helicases play roles in various essential biological processes such as RNA splicing and editing. Recent in vitro studies show that RNA helicases are involved in immune responses toward viruses, serving as viral RNA sensors or immune signaling adaptors. However, there is still a lack of in vivo data to support the tissue- or cell-specific function of RNA helicases owing to the lethality of mice with complete knockout of RNA helicases; further, there is a lack of evidence about the antibacterial role of helicases. Here, we investigated the in vivo role of Dhx15 in intestinal antibacterial responses by generating mice that were intestinal epithelial cell (IEC)-specific deficient for Dhx15 (Dhx15 f/f Villin1-cre, Dhx15ΔIEC). These mice are susceptible to infection with enteric bacteria Citrobacter rodentium (C. rod), owing to impaired α-defensin production by Paneth cells. Moreover, mice with Paneth cell-specific depletion of Dhx15 (Dhx15 f/f Defensinα6-cre, Dhx15ΔPaneth) are more susceptible to DSS (dextran sodium sulfate)-induced colitis, which phenocopy Dhx15ΔIEC mice, due to the dysbiosis of the intestinal microbiota. In humans, reduced protein levels of Dhx15 are found in ulcerative colitis (UC) patients. Taken together, our findings identify a key regulator of Wnt-induced α-defensins in Paneth cells and offer insights into its role in the antimicrobial response as well as intestinal inflammation.

Compartmentalized Innate Immune Response of Human Fetal Membranes against Escherichia coli Choriodecidual Infection.

An infectious process into the uterine cavity represents a major endangered condition that compromises the immune privilege of the maternal-fetal unit and increases the risk for preterm birth (PTB) and premature rupture of membranes (PROM). Fetal membranes are active secretors of antimicrobial peptides (AMP), which limit bacterial growth, such as Escherichia coli. Nevertheless, the antibacterial responses displayed by chorioamniotic membranes against a choriodecidual E. coli infection have been briefly studied. The objective of this research was to characterize the profile of synthesis, activity, and spatial distribution of a broad panel of AMPs produced by fetal membranes in response to E. coli choriodecidual infection. Term human chorioamniotic membranes were mounted in a two independent compartment model in which the choriodecidual region was infected with live E. coli (1 × 105 CFU/mL). Amnion and choriodecidual AMP tissue levels and TNF-α and IL-1ß secretion were measured by the enzyme-linked immunosorbent assay. The passage of bacterium through fetal membranes and their effect on structural continuity was followed for 24 h. Our results showed that E. coli infection caused a progressive mechanical disruption of the chorioamniotic membranes and an activated inflammatory environment. After the challenge, the amnion quickly (2-4 h) induced production of human beta defensins (HBD)-1, HBD-2, and LL-37. Afterwards (8-24 h), the amnion significantly produced HBD-1, HBD-2, HNP-1-3, S100A7, sPLA2, and elafin, whereas the choriodecidua induced LL-37 synthesis. Therefore, we noticed a temporal- and tissue-specific pattern regulation of the synthesis of AMPs by infected fetal membranes. However, fetal membranes were not able to contain the collagen degradation or the bacterial growth and migration despite the battery of produced AMPs, which deeply increases the risk for PTB and PROM. The mixture of recombinant HBDs at low concentrations resulted in increased bactericidal activity compared to each HBD alone in vitro, encouraging further research to study AMP combinations that may offer synergy to control drug-resistant infections in the perinatal period.

Significant elevation of salivary human neutrophil peptides 1-3 levels by probiotic milk in preschool children with severe early childhood caries: a randomized controlled trial.

OBJECTIVES: To determine salivary human neutrophil peptides 1-3 (HNP1-3) levels in caries-free preschool children and in those with early childhood caries (ECC) or severe-ECC, in a daily probiotic group, receiving reconstituted milk with the probiotic Lactobacillus paracasei SD1 once daily; a triweekly probiotic group, receiving the probiotic milk 3 days a week; and a placebo group. MATERIALS AND METHODS: Oral examination and unstimulated whole saliva collection were conducted in 354 children at baseline, 6 months after intervention (T6), and after probiotic discontinuation (T12). Of the 354, adequate volume of saliva samples from 268 children were simultaneously analyzed for Streptococcus mutans and total lactobacilli levels using qPCR and for HNP1-3 levels using ELISA. RESULTS: In the severe-ECC status, significant increases in the median HNP1-3 levels at T12 were found in both daily and triweekly probiotic groups (p < 0.001). The median S. mutans levels in the daily group were significantly decreased at T6 and T12 (p < 0.01), whereas the median total lactobacilli levels were significantly increased at T6 (p < 0.001). Significantly inverse correlations between altered HNP1-3 and S. mutans levels and significant decreases in caries progression were found in both probiotic groups (p < 0.05). CONCLUSIONS: In the severe-ECC status, daily or triweekly consumption of L. paracasei SD1 significantly enhanced salivary HNP1-3 levels, but reduced S. mutans levels, possibly resulting in reduction of caries progression. CLINICAL RELEVANCE: Significant enhancement of salivary HNP1-3 levels by probiotic consumption is associated with reduction in S. mutans levels, consistent with diminished caries progression in children with severe-ECC.

Accuracy and Cost-Effectivenss of a Novel Method for Alpha Defensins Measurement in the Diagnosis of Periprosthetic Joint Infections.

BACKGROUND: Two methods for detecting synovial fluids alpha defensins are available: the enzyme-linked immunosorbent assay and the lateral flow test. For both, the proper role and accuracy remain uncertain. The purpose of this study was to assess the accuracy of the matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) for alpha defensin detection in synovial fluids of patients with total knee arthroplasty/total hip arthroplasty failures. The hypothesis was that the alpha defensin measurement through MALDI-TOF MS assay could be a high sensitive and specific test for periprosthetic joint infections (PJI) diagnosis as compared with Musculoskeletal Infection Society (MSIS) criteria. METHODS: The study included 138 patients. The 2018 MSIS criteria were used to diagnose PJIs. Synovial fluids were assessed for routinely synovial fluid tests and alpha defensin measurement through MALDI-TOF MS. Sensitivity, specificity, overall diagnostic accuracy, positive and negative predictive values, receiver operator curves, and area under the curve were calculated. RESULTS: As per the 2018 MSIS criteria, 59 PJIs (43%) and 79 aseptic failures (57%) were diagnosed. The MALDI-TOF MS assay showed an overall accuracy of 94.9%. The sensitivity was 93%, the specificity was 96%, the positive predictive value was 95%, and the negative predictive value was 95%. Receiver operator curves analysis demonstrates an area under the curve of 0.95 (P < .001). CONCLUSION: The MALDI-TOF MS assay showed high sensitivity and specificity for alpha defensin detection in case of total knee arthroplasty/total hip arthroplasty failures. The advantages of the technology, such as the few milliliters of sample needed, the rapidity of obtaining results, and the cost-effectiveness of the procedure could make the MALDI-TOF MS alpha defensin assay a useful and widespread test in clinical practice.

Management of Staphylococcus Mediated Systemic Infection by Enhancing the Resurging Activity of Co-trimoxazole in Presence of Cryptdin-2.

Resurgence of sensitivity of the antibiotics, to which the pathogen had developed resistance in the past, requires special attention for strengthening the reservoir of antimicrobial compounds. Reports in the recent past have suggested that co-trimoxazole (COT) has regained its activity against methicillin resistant Staphylococcus aureus (MRSA). The present study exploited the use of COT in the presence of an antimicrobial peptide (AMP), cryptdin-2 (a murine Paneth cell alpha defensin), in order to reduce the selective pressure of the antibiotic on the pathogen. In vitro antibacterial activity and in vivo efficacy of the combination was ascertained against MRSA induced systemic infection using a murine model. Observations of the present study might help in restoring the regained activity of conventional antibiotics, such as COT, when used in combination with novel antimicrobial molecules like AMPs. This might prove as a viable strategy to eliminate the chances of re-occurrence of resistance due to their multi-prong targeting and synergistically combating infections caused by these resistant pathogens.

Human Neutrophil Alpha-Defensins Promote NETosis and Liver Injury in Alcohol-Related Liver Cirrhosis: Potential Therapeutic Agents.

Background: Neutrophils are thought to play a pivotal role in the pathogenesis of many inflammatory diseases, such as hepatitis, liver cirrhosis, etc. Activated human neutrophils release human neutrophil peptides (HNP1-3) or alpha-defensins that are antimicrobial peptides in azurophil granules. Furthermore, HNP1-3 build a scaffold of neutrophil extracellular traps (NETs) and promote the process of programmed cell death called NETosis. Our study aimed to investigate the role of alpha-defensins in the pathogenesis of alcohol-related liver cirrhosis (ALC). Methods: The concentrations of alpha-defensins in the plasma of 62 patients with ALC and 24 healthy subjects were measured by ELISA. The patients with ALC were prospectively recruited based on the severity of liver dysfunction according to the Child-Pugh and Model of End-Stage Liver Disease-Natrium (MELD-Na) scores, modified Maddrey's Discriminant Function (mDF), and the presence of ALC complications. Results: The concentrations of alpha-defensins in plasma were significantly higher in the ALC patients than in the controls. The plasma levels of HNP1-3 correlated with the MELD and mDF scores. ALC subgroups with MELD > 20 and mDF > 32 displayed significantly higher HNP1-3 concentrations. The plasma levels of HNP1-3 revealed a good predictive AUC for hepatic encephalopathy and ascites development (0.81 and 0.74, respectively) and for patient survival (0.87) in those over 40 years of age. Conclusion: These findings suggest that alpha-defensins play an important role in the assessment of ALC.

Advancing the Diagnosis of Periprosthetic Joint Infections: Integrated Microfluidic Platform for Alpha-Defensins-Specific Aptamer Selection and Its Analytical Applications.

Periprosthetic joint infections (PJIs) pose a significant challenge in orthopedic surgery, particularly total joint arthroplasty (TJA), due to the potential for implant failure and increased patient morbidity. Early and accurate detection of PJIs is crucial for timely intervention and better patient prognosis. Herein, we successfully screened a high-affinity aptamer targeting alpha-defensin complex human neutrophil protein 1-3 (HNP 1-3; potential PJI biomarkers in synovial fluid [SF]) for the first time using systematic evolution of ligands by exponential enrichment (SELEX) on an integrated microfluidic platform. The compact microfluidic device enabled efficient screening, with each round completed within <2 h, comprising five rounds of positive selection, two rounds of negative selection, and one round of competitive selection. A novel one-aptamer-one-antibody assay was further developed from the optimal aptamer screened, and it could accurately quantify HNP 1-3 in SF within 3 h with only ∼50 µL of SF. The assay demonstrated strong binding affinity and specificity for the target protein in SF. Thirteen PJI SF samples were accurately diagnosed and the assay was accurate over a wide dynamic range (0.32-100 mg/L). This study has showcased a rapid and accurate diagnostic tool for PJI detection, which should see widespread use in the clinic, holding promise for potential analytical applications in orthopedic surgery and improving patient care.

ProHNPs are the principal α-defensins of human plasma.

BACKGROUND: Human neutrophil peptides (HNPs) were discovered as abundant antimicrobial peptides of azurophil granules. Later studies revealed that most HNPs were produced by myelocytes and metamyelocytes and secreted into the bone marrow plasma as the inert proforms, proHNPs. Despite the vast amounts of proHNPs released into bone marrow plasma, little has been done to characterize these. Numerous studies have investigated HNPs in plasma, linking them to a variety of diseases, but without distinguishing between HNPs and their proforms. MATERIALS AND METHODS: We used an antibody with specificity against the propiece of proHNPs to investigate proHNPs in plasma and tissue. RESULTS: In contrast to previous studies using HNP antibodies, we found proHNPs to be many-fold more abundant than HNPs in plasma with a mean concentration of 2 µg/mL. The concentration was substantially higher in bone marrow plasma in accordance with the bone marrow being the site of origin of plasma proHNPs. ProHNPs were not bound to high molecular weight plasma proteins. Accordingly, proHNPs were filtered in the kidneys and resorbed in the proximal tubules. CONCLUSIONS: Most HNPs in plasma are in fact proHNPs, which is important given the differences in their origin and biological activities.

Salivary Human ß-Defensin 1-3 and Human α-Defensin-1 Levels in Relation to the Extent of Periodontal Disease and Tooth Loss in the Elderly.

The oral innate immune response may diminish with aging. In the present study, the aim was to examine human ß-defensin (hBD) 1-3 and human neutrophil peptide (HNP)-1 levels in the saliva of an elderly population to establish the extent of periodontal disease and tooth loss. A total of 175 individuals aged ≥ 65 years were divided into five groups based on the number of teeth with a pocket depth ≥ 4 mm as follows: 17 pocket-free individuals (Control), 55 individuals having 1-6 pocket teeth (PerioA), 33 individuals having 7-13 pocket teeth (PerioB), 29 individuals having at least 14 pocket teeth (PerioC), and 41 edentulous individuals. Their salivary defensin levels were measured with ELISA kits. The salivary HNP-1 levels were significantly higher in the Perio groups (PerioB: p < 0.001 and PerioC: p < 0.001) in comparison to the Control. The associations between salivary HNP-1 levels and the number of pocket teeth remained significant after adjustments for age, gender, level of education, and number of teeth. The salivary HNP and hBD levels differed in terms of their correlation to the extent of periodontal disease and tooth loss in the elderly.

Alpha-defensins determination in different types of synovial fluid and parallel collected serum samples by ELISA.

AIMS: The study aims were to verify the serum (S) and synovial fluid (SF) reference intervals (RIs) for human neutrophil defensins (HNP1-3); measure S and SF defensin concentrations in different types of SF, including non-inflammatory, inflammatory non-pyogenic, inflammatory pyogenic, and hemorrhagic; and to compare the HNP1-3 concentrations in SF and S with those of other inflammatory biomarkers. METHODS: SF and S samples were collected from 92 patients. HNP1-3 concentrations were determined using enzyme-linked immunosorbent assays; glucose, lactate, interleukin-6, and procalcitonin using an automatic analyzer; and presepsin using a Pathfast system. There were 61 non-inflammatory, 11 inflammatory non-pyogenic, 11 inflammatory pyogenic, and 9 hemorrhagic SF. Non-inflammatory SF was divided into non-inflammatory normal and non-inflammatory osteoarthritis. The former was used to estimate the HNP1-3 RI in SF and S. RESULTS: The estimated HNP1-3 RIs of SF and S were 12.47-437.42 mg/L and 5.45-44.75 µg/L, respectively. HNP1-3 differed significantly between S and SF and individual groups of SF (P<0.001 and P=0.001, respectively). There were significant relationships between SF HNP1-3 and S HNP1-3 (P<0.001), S C-reactive protein (P<0.001), and S interleukin-6 (P=0.007), and between SF HNP1-3 and SF C-reactive protein (P=0.004) and SF interleukin-6 (P<0.001). The highest kappa coefficient was between SF HNP1-3 and SF interleukin-6 (κ=0.507). CONCLUSIONS: We validated the SF HNP1-3 diagnostic kit and demonstrated that SF and S HNP1-3 are promising biomarkers for distinguishing inflammatory from non-inflammatory joint diseases.

Inhibition of defensin A and cecropin A responses to dengue virus 1 infection in Aedes aegypti. / Inhibición de las respuestas de defensina A y cecropina A contra la infección del virus dengue 1 en Aedes aegypti

INTRODUCTION: It is essential to determine the interactions between viruses and mosquitoes to diminish dengue viral transmission. These interactions constitute a very complex system of highly regulated pathways known as the innate immune system of the mosquito, which produces antimicrobial peptides that act as effector molecules against bacterial and fungal infections. There is less information about such effects on virus infections. OBJECTIVE: To determine the expression of two antimicrobial peptide genes, defensin A and cecropin A, in Aedes aegypti mosquitoes infected with DENV-1. MATERIALS AND METHODS: We used the F1 generation of mosquitoes orally infected with DENV-1 and real-time PCR analysis to determine whether the defensin A and cecropin A genes played a role in controlling DENV-1 replication in Ae. aegypti. As a reference, we conducted similar experiments with the bacteria Escherichia coli. RESULTS: Basal levels of defensin A and cecropin A mRNA were expressed in uninfected mosquitoes at different times post-blood feeding. The infected mosquitoes experienced reduced expression of these mRNA by at least eightfold when compared to uninfected control mosquitoes at all times post-infection. In contrast with the behavior of DENV-1, results showed that bacterial infection produced up-regulation of defensin and cecropin genes; however, the induction of transcripts occurred at later times (15 days). CONCLUSION: DENV-1 virus inhibited the expression of defensin A and cecropin A genes in a wild Ae. aegypti population from Venezuela.

Introducción. Es esencial determinar las interacciones entre los virus y los mosquitos para disminuir la transmisión viral. Estas interacciones constituyen un sistema muy complejo y muy regulado conocido como sistema inmunitario innato del mosquito, el cual produce péptidos antimicrobianos, moléculas efectoras que funcionan contra las infecciones bacterianas y fúngicas; se tiene poca información de su acción sobre los virus. Objetivo. Determinar la expresión de dos genes AMP (defensina A y cecropina A) en mosquitos Aedes aegypti infectados con el virus DENV-1. Materiales y métodos. Se infectaron oralmente mosquitos de generación F1 con DENV-1 y mediante el análisis con PCR en tiempo real se determinó el potencial papel de los genes defensina A y cecropina A en el control de la replicación del DENV-1 en Ae. aegypti. Como referencia, se infectaron mosquitos con Escherichia coli. Resultados: Los mosquitos no infectados expresaron niveles basales de los ARNm de los genes defensina A y cecropina A en diversos momentos después de la alimentación. Los mosquitos infectados experimentaron una reducción, por lo menos, de ocho veces en la expresión de estos ARNm con respecto a los mosquitos de control en todo el periodo posterior a la alimentación. En contraste con el comportamiento del virus DENV-1, los resultados mostraron que la infección bacteriana produjo una regulación positiva de los genes defensina y cecropina; sin embargo, la inducción de los transcritos ocurrió tardíamente (15 días). Conclusión. El virus DENV-1 inhibió la expresión de los genes defensina A y cecropina A en una población silvestre de Ae. aegypti en Venezuela.

Smoking reduces cathelicidin LL-37 and human neutrophil peptide 1-3 levels in the gingival crevicular fluid of patients with periodontitis.

BACKGROUND: Antimicrobial peptides are components of innate immune response that have a key role on susceptibility and resistance of the oral cavity to diseases. This study aimed to investigate the influence of smoking on cathelicidin LL-37 and human neutrophil peptides 1 through 3 (HNP 1-3) levels in the gingival crevicular fluid (GCF) of patients with periodontitis. The relationship between levels of these peptides with the periodontal status and selected inflammatory mediators levels in smokers and non-smokers was also evaluated. METHODS: Forty patients with periodontitis, 20 smokers and 20 non-smokers were recruited. After a full periodontal clinical assessment, GCF samples were collected from healthy (n = 5) and diseased (n = 5) sites of each patient. Peptides and inflammatory mediators in the GCF were quantitated by sandwich ELISAs and Multiplex assay, respectively. RESULTS: Diseased sites had significantly (P <0.05) higher levels of LL-37 and lower levels of HNP 1-3 than healthy sites in both smokers and non-smokers. Diseased sites of smokers presented significantly lower levels of LL-37 and HNP 1-3 when compared with diseased sites of non-smokers. Concentration of LL-37 was directly correlated with the presence of proinflammatory mediators matrix metalloproteinase (MMP)-8 and interleukin (IL)-1ß and inversely correlated with concentration of IL-10. HNP 1-3 concentration was positively correlated with IL-10 and negatively correlated with concentrations of MMP-8 and IL-1ß. CONCLUSIONS: Smoking was associated with reduced levels of LL-37 and HNP 1-3 in GCF of patients with periodontitis. LL-37 had a distinct expression pattern from HNP 1-3: LL-37 was upregulated in diseased sites, and HNP 1-3 was increased in periodontally healthy sites.1.

Theta-Defensins Inhibit High-Risk Human Papillomavirus Infection Through Charge-Driven Capsid Clustering.

Persistent infection with high-risk human papillomavirus (hrHPV) genotypes results in a large number of anogenital and head and neck cancers worldwide. Although prophylactic vaccination coverage has improved, there remains a need to develop methods that inhibit viral transmission toward preventing the spread of HPV-driven disease. Defensins are a class of innate immune effector peptides that function to protect hosts from infection by pathogens such as viruses and bacteria. Previous work utilizing α and ß defensins from humans has demonstrated that the α-defensin HD5 is effective at inhibiting the most common high-risk genotype, HPV16. A third class of defensin that has yet to be explored are θ-defensins: small, 18-amino acid cyclic peptides found in old-world monkeys whose unique structure makes them both highly cationic and resistant to degradation. Here we show that the prototype θ-defensin, rhesus theta defensin 1, inhibits hrHPV infection through a mechanism involving capsid clustering that inhibits virions from binding to cell surface receptor complexes.

α-Defensin HD5 Stabilizes Human Papillomavirus 16 Capsid/Core Interactions.

BACKGROUND: Human papillomavirus (HPV) is linked to nearly all cases of cervical cancer. Despite available vaccines, a deeper understanding of the immune response to HPV is needed. Human α-defensin 5 (HD5), an innate immune effector peptide, blocks infection of multiple sero-types of HPV, including high-risk HPV16. While a common mechanism of α-defensin anti-viral activity against nonenveloped viruses such as HPV has emerged, there is limited understanding of how α-defensins bind to viral capsids to block infection. METHODS: We have used cryo-electron microscopy (cryoEM), mass spectrometry (MS) crosslinking and differential lysine modification studies, and molecular dynamics (MD) simulations to probe the interaction of HPV16 pseudovirions (PsVs) with HD5. RESULTS: CryoEM single particle reconstruction did not reveal HD5 density on the capsid surface. Rather, increased density was observed under the capsid shell in the presence of HD5. MS studies indicate that HD5 binds near the L1 and L2 capsid proteins and specifically near the C-terminal region of L1. MD simulations indicate that favorable electrostatic interactions can be formed between HD5 and the L1 C-terminal tail. CONCLUSIONS: A model is presented for how HD5 affects HPV16 structure and cell entry. In this model, HD5 binds to disordered regions of L1 and L2 protruding from the icosahedrally ordered capsid. HD5 acts to cement interactions between L1 and L2 and leads to a closer association of the L2/genome core with the L1 capsid. This model provides a structural rationale for our prior observation that HD5 interferes with the separation of L1 from the L2/genome complex during cell entry.

Murine adenoviruses: tools for studying adenovirus pathogenesis in a natural host.

Small laboratory animals are powerful models for investigating in vivo viral pathogenesis of a number of viruses. For adenoviruses (AdVs), however, species-specificity poses limitations to studying human adenoviruses (HAdVs) in mice and other small laboratory animals. Thus, this review covers work on naturally occurring mouse AdVs, primarily mouse adenovirus type 1 (MAdV-1), a member of the species Murine mastadenovirus A. Molecular genetics, virus life cycle, cell and tissue tropism, interactions with the host immune response, persistence, and host genetics of susceptibility are described. A brief discussion of MAdV-2 (member of species Murine mastadenovirus B) and MAdV-3 (member of species Murine mastadenovirus C) is included. We report the use of MAdVs in the development of vectors and vaccines.

The Effect of Nonsurgical Periodontal Therapy on HNP1-3 Level in Gingival Crevicular Fluid of Chronic Periodontitis Patients.

The rich bacterial flora of oral cavity is controlled by innate immune response, including antibacterial peptides and among them human neutrophil peptides 1-3 (HNP1-3). The knowledge of the involvement of HNPs in innate and acquired immunity of the periodontium is fragmentary. The aim of the study was to assess alterations in HNP1-3 levels in the gingival crevicular fluid (GCF) of chronic periodontitis patients before and after nonsurgical periodontal therapy. Nineteen patients with chronic periodontitis were qualified to the study. After periodontal examination, one site with pocket depth (PD) ≥4 mm was selected. All the patients received periodontal treatment involving scaling and root planing with additional systemic antibiotic therapy (Amoxicillin 375 mg three times daily and Metronidazole 250 mg three times daily for 7 days). Prior to therapy, 3 and 6 months after it, clinical periodontal parameters were measured and GCF was collected from previously chosen site. The level of HNP1-3 in GCF was determined by means of a commercially available enzyme-linked immunoassay kit. The periodontal therapy caused a statistically significant (p < 0.001) decrease in all the assessed clinical parameters at the sites of sample collection except for bleeding on probing. The level of HNP1-3 per measure point showed a statistically significant increase (baseline-3 months: p = 0.05, baseline-6 months: p = 0.007). Within the limits of the study, it can be stated that nonsurgical periodontal therapy with additional systemic administration of Amoxicillin and Metronidazole increases the level of HNP1-3 in GCF.

Vitamin D Promotes Pneumococcal Killing and Modulates Inflammatory Responses in Primary Human Neutrophils.

Streptococcus pneumoniae is a major human pathogen and a leading cause of pneumonia, septicemia, and meningitis worldwide. Despite clinical studies linking vitamin D deficiency and pneumonia, molecular mechanisms behind these observations remain unclear. In particular, the effects of vitamin D on neutrophil responses remain unknown. Using pneumococcal strains, primary neutrophils isolated from human blood, and sera from patients with frequent respiratory tract infections (RTIs), we investigated the effects of vitamin D on neutrophil bactericidal and inflammatory responses, including pattern recognition receptors, antimicrobial peptides, and cytokine regulation. We found that vitamin D upregulated pattern recognition receptors, TLR2, and NOD2, and induced the antimicrobial human neutrophil peptides (HNP1-3) and LL-37, resulting in increased killing of pneumococci in a vitamin D receptor-dependent manner. Antibodies targeting HNP1-3 inhibited bacterial killing. Vitamin D supplementation of serum from patients with bacterial RTIs enhanced neutrophil killing. Moreover, vitamin D lowered inflammatory cytokine production by infected neutrophils via IL-4 production and the induction of suppressor of cytokine signaling (SOCS) proteins SOCS-1 and SOCS-3, leading to the suppression of NF-κB signaling. Thus, vitamin D enhances neutrophil killing of S. pneumoniae while dampening excessive inflammatory responses and apoptosis, suggesting that vitamin D could be used alongside antibiotics when treating pneumococcal infections.

Guardians of the Gut: Enteric Defensins.

Enteric defensins likely play a key role in the management of the human microbiome throughout development. The functional and mechanistic diversity of defensins is much greater than was initially thought. Defensin expression and overall Paneth cell physiology likely plays a key role in the development of colitis and other inflammatory or dysbiotic diseases of the gut. As our understanding of enteric defensins grows, their potential as tools of clinical intervention becomes more apparent. In this review, we focus on the function and activity of Paneth Cell defensins and highlight their role in disease.

Inhibition of defensin A and cecropin A responses to dengue virus 1 infection in Aedes aegypti / Inhibición de las respuestas de defensina A y cecropina A contra la infección del virus dengue 1 en Aedes aegypti

Abstract | Introduction: It is essential to determine the interactions between viruses and mosquitoes to diminish dengue viral transmission. These interactions constitute a very complex system of highly regulated pathways known as the innate immune system of the mosquito, which produces antimicrobial peptides that act as effector molecules against bacterial and fungal infections. There is less information about such effects on virus infections. Objective: To determine the expression of two antimicrobial peptide genes, defensin A and cecropin A, in Aedes aegypti mosquitoes infected with DENV-1. Materials and methods: We used the F1 generation of mosquitoes orally infected with DENV-1 and real-time PCR analysis to determine whether the defensin A and cecropin A genes played a role in controlling DENV-1 replication in Ae. aegypti. As a reference, we conducted similar experiments with the bacteria Escherichia coli. Results: Basal levels of defensin A and cecropin A mRNA were expressed in uninfected mosquitoes at different times post-blood feeding. The infected mosquitoes experienced reduced expression of these mRNA by at least eightfold when compared to uninfected control mosquitoes at all times post-infection. In contrast with the behavior of DENV-1, results showed that bacterial infection produced up-regulation of defensin and cecropin genes; however, the induction of transcripts occurred at later times (15 days). Conclusion: DENV-1 virus inhibited the expression of defensin A and cecropin A genes in a wild Ae. aegypti population from Venezuela.

Resumen | Introducción. Es esencial determinar las interacciones entre los virus y los mosquitos para disminuir la transmisión viral. Estas interacciones constituyen un sistema muy complejo y muy regulado conocido como sistema inmunitario innato del mosquito, el cual produce péptidos antimicrobianos, moléculas efectoras que funcionan contra las infecciones bacterianas y fúngicas; se tiene poca información de su acción sobre los virus. Objetivo. Determinar la expresión de dos genes AMP (defensina A y cecropina A) en mosquitos Aedes aegypti infectados con el virus DENV-1. Materiales y métodos. Se infectaron oralmente mosquitos de generación F1 con DENV-1 y mediante el análisis con PCR en tiempo real se determinó el potencial papel de los genes defensina A y cecropina A en el control de la replicación del DENV-1 en Ae. aegypti. Como referencia, se infectaron mosquitos con Escherichia coli. Resultados: Los mosquitos no infectados expresaron niveles basales de los ARNm de los genes defensina A y cecropina A en diversos momentos después de la alimentación. Los mosquitos infectados experimentaron una reducción, por lo menos, de ocho veces en la expresión de estos ARNm con respecto a los mosquitos de control en todo el periodo posterior a la alimentación. En contraste con el comportamiento del virus DENV-1, los resultados mostraron que la infección bacteriana produjo una regulación positiva de los genes defensina y cecropina; sin embargo, la inducción de los transcritos ocurrió tardíamente (15 días). Conclusión. El virus DENV-1 inhibió la expresión de los genes defensina A y cecropina A en una población silvestre de Ae. aegypti en Venezuela.

Characterization of salivary proteins of schizophrenic and bipolar disorder patients by top-down proteomics.

The analysis of whole saliva of 32 subjects with diagnosis of schizophrenia (SZ), 17 with diagnosis of bipolar disorder (BD), and 31 healthy subjects divided in non-smokers (HN; n=19) and smokers (HS; n=12) using an HPLC-ESI-MS top-down platform is reported in this study. Both SZ and BD revealed more than 10 fold mean increase of α-defensins 1-4, S100A12, cystatin A and S-derivatives of cystatin B levels with respect to the HN and HS control groups. No differences of protein levels were observed between SZ and BD groups and between HN and HS groups. Moreover, the correlation coefficients among the different proteins were significantly better in BD group than in SZ group. BIOLOGICAL SIGNIFICANCE: This study on whole saliva confirms a schizophrenia-associated dysregulation of immune pathway of peripheral white blood cells and suggests that the dysregulation of BD group could involve the activation of more specific cell type than that of SZ group.