Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Rhesus macaque θ-defensin isoforms: expression, antimicrobial activities, and demonstration of a prominent role in neutrophil granule microbicidal activities.

ABSTRACT: Mammalian defensins are cationic, antimicrobial peptides that play a central role in innate immunity. The peptides are composed of three structural subfamilies: α-, β-, and θ-defensins. θ-defensins are macrocyclic octadecapeptides expressed only in Old World monkeys and orangutans and are produced by the pair-wise, head-to-tail splicing of nonapeptides derived from their respective precursors. The existence of three active θ-defensin genes predicts that six different RTDs (1-6) are produced in this species. In this study, we isolated and quantified RTDs 1-6 from the neutrophils of 10 rhesus monkeys. RTD-1 was the most abundant θ-defensin, constituting ~50% of the RTD content; total RTD content varied by as much as threefold between animals. All peptides tested were microbicidal at ∼1 μM concentrations. The contribution of θ-defensins to macaque neutrophil antimicrobial activity was assessed by analyzing the microbicidal properties of neutrophil granule extracts after neutralizing θ-defensin content with a specific antibody. θ-defensin neutralization markedly reduced microbicidal activities of the corresponding extracts. Macaque neutrophil granule extracts had significantly greater microbicidal activity than those of human neutrophils, which lack θ-defensins. Supplementation of human granule extracts with RTD-1 markedly increased the microbicidal activity of these preparations, further demonstrating a prominent microbicidal role for θ-defensins.

SUBMITTER: Tongaonkar P

PROVIDER: S-EPMC3024902 | biostudies-other | 2011 Feb

REPOSITORIES: biostudies-other

ACCESS DATA

Json Xml

Similar Datasets

Synthesis, structure, and activities of an oral mucosal alpha-defensin from rhesus macaque.

Project description:The oral cavity is an environment challenged by a large variety of pathogens. Consequently, the antimicrobial peptides expressed in that environment are interesting as they evolved to defend against a broad spectrum of bacteria and fungi. Here we report the discovery of new alpha-defensins from rhesus macaque oral mucosa and determine the first alpha-defensin structure from that species. The new peptides were identified by sequencing of reverse transcriptase-PCR products obtained from oral mucosal tissues, disclosing three mucosal alpha-defensins, termed rhesus macaque oral alpha-defensins (ROADs). The peptide corresponding to fully processed ROAD-1 was synthesized, subjected to folding/oxidation conditions, and purified. ROAD-1 was active against Staphylococcus aureus, Escherichia coli, and Candida albicans in a concentration-dependent manner. We determined the structure of ROAD-1 using NMR spectroscopy and find that the synthetic peptide adopts the canonical disulfide pairing and alpha-defensin fold. The antimicrobial mechanism of defensins has been correlated with their ability to disrupt and permeabilize the cell envelope, activities that depend on the surface features of the folded peptide. Although ROAD-1 maintains the defensin fold, the oral defensin displays distinct surface features when compared with other alpha-defensin structures.

| S-EPMC2602889 | biostudies-literature

In vitro activation of the rhesus macaque myeloid alpha-defensin precursor proRMAD-4 by neutrophil serine proteinases.

Project description:Alpha-defensins are mammalian antimicrobial peptides expressed mainly by cells of myeloid lineage or small intestinal Paneth cells. The peptides are converted from inactive 8.5-kDa precursors to membrane-disruptive forms by post-translational proteolytic events. Because rhesus myeloid pro-alpha-defensin-4 (proRMAD-4((20-94))) lacks bactericidal peptide activity in vitro, we tested whether neutrophil azurophil granule serine proteinases, human neutrophil elastase (NE), cathepsin G (CG), and proteinase-3 (P3) have in vitro convertase activity. Only NE cleaved proRMAD-4((20-94)) at the native RMAD-4 N terminus to produce fully processed, bactericidal RMAD-4((62-94)). The final CG cleavage product was RMAD-4((55-94)), and P3 produced both RMAD-4((55-94)) and RMAD-4(57-94). Nevertheless, NE, CG, and P3 digests of proRMAD4 and purified RMAD-4((62-94)), RMAD-4((55-94)), and RMAD-4(57-94) peptides had equivalent in vitro bactericidal activities. Bactericidal peptide activity assays of proRMAD-4((20-94)) variants containing complete charge-neutralizing D/E to N/Q or D/E to A substitutions showed that (DE/NQ)-proRMAD-4((20-94)) and (DE/A)-proRMAD-4((20-94)) were as active as mature RMAD-4((62-94)). Therefore, proregion Asp and Glu side chains inhibit the RMAD-4 component of full-length proRMAD-4((20-94)), perhaps by a combination of charge-neutralizing and hydrogen-bonding interactions. Although native RMAD-4((62-94)) resists NE, CG, and P3 proteolysis completely, RMAD-4((62-94)) variants with disulfide pairing disruptions or lacking disulfide bonds were degraded extensively, evidence that the disulfide array protects the alpha-defensin moiety from degradation by the myeloid converting enzymes. These in vitro analyses support the conclusion that rhesus macaque myeloid pro-alpha-defensins are converted to active forms by serine proteinases that co-localize in azurophil granules.

| S-EPMC2583298 | biostudies-other

Rhesus Theta Defensin 1 Promotes Long Term Survival in Systemic Candidiasis by Host Directed Mechanisms.

Project description:Invasive candidiasis is an increasingly frequent cause of serious and often fatal infections in hospitalized and immunosuppressed patients. Mortality rates associated with these infections have risen sharply due to the emergence of multidrug resistant (MDR) strains of C. albicans and other Candida spp., highlighting the urgent need of new antifungal therapies. Rhesus theta (θ) defensin-1 (RTD-1), a natural macrocyclic antimicrobial peptide, was recently shown to be rapidly fungicidal against clinical isolates of MDR C. albicans in vitro. Here we found that RTD-1 was rapidly fungicidal against blastospores of fluconazole/caspofungin resistant C. albicans strains, and was active against established C. albicans biofilms in vitro. In vivo, systemic administration of RTD-1, initiated at the time of infection or 24 h post-infection, promoted long term survival in candidemic mice whether infected with drug-sensitive or MDR strains of C. albicans. RTD-1 induced an early (4 h post treatment) increase in neutrophils in naive and infected mice. In vivo efficacy was associated with fungal clearance, restoration of dysregulated inflammatory cytokines including TNF-α, IL-1β, IL-6, IL-10, and IL-17, and homeostatic reduction in numbers of circulating neutrophils and monocytes. Because these effects occurred using peptide doses that produced maximal plasma concentrations (Cmax) of less than 1% of RTD-1 levels required for in vitro antifungal activity in 50% mouse serum, while inducing a transient neutrophilia, we suggest that RTD-1 mediates its antifungal effects in vivo by host directed mechanisms rather than direct fungicidal activity. Results of this study suggest that θ-defensins represent a new class of host-directed compounds for treatment of disseminated candidiasis.

| S-EPMC6858451 | biostudies-literature

Suppression and resolution of autoimmune arthritis by rhesus θ-defensin-1, an immunomodulatory macrocyclic peptide.

Project description:θ-defensins constitute a family of macrocyclic peptides expressed exclusively in Old World monkeys. The peptides are pleiotropic effectors of innate immunity, possessing broad spectrum antimicrobial activities and immunoregulatory properties. Here we report that rhesus θ-defensin 1 (RTD-1) is highly effective in arresting and reversing joint disease in a rodent model of rheumatoid arthritis (RA). Parenteral RTD-1 treatment of DA/OlaHsd rats with established pristane-induced arthritis (PIA) rapidly suppressed joint disease progression, restored limb mobility, and preserved normal joint architecture. RTD-1 significantly reduced joint IL-1β levels compared with controls. RTD-1 dose-dependently inhibited fibroblast-like synoviocyte (FLS) invasiveness and FLS IL-6 production. Consistent with the inhibition of FLS invasiveness, RTD-1 was a potent inhibitor of arthritogenic proteases including ADAMs 17 and 10 which activate TNFα, and inhibited matrix metalloproteases, and cathepsin K. RTD-1 was non-toxic, non-immunogenic, and effective when administered as infrequently as once every five days. Thus θ-defensins, which are absent in humans, have potential as retroevolutionary biologics for the treatment of RA.

| S-EPMC5690597 | biostudies-literature

Efficacy of Rhesus Theta-Defensin-1 in Experimental Models of Pseudomonas aeruginosa Lung Infection and Inflammation.

Project description:Chronic airway infection and inflammation contribute to the progressive loss of lung function and shortened survival of patients with cystic fibrosis (CF). Rhesus theta defensin-1 (RTD-1) is a macrocyclic host defense peptide with antimicrobial and immunomodulatory activities. Combined with favorable preclinical safety and peptide stability data, RTD-1 warrants investigation to determine its therapeutic potential for treatment of CF lung disease. We sought to evaluate the therapeutic potential of RTD-1 for CF airway infection and inflammation using in vitro, ex vivo, and in vivo models. We evaluated RTD-1's effects on basal and Pseudomonas aeruginosa-induced inflammation in CF sputum leukocytes and CF bronchial epithelial cells. Peptide stability was evaluated by incubation with CF sputum. Airway pharmacokinetics, safety, and tolerance studies were performed in naive mice. Aerosolized RTD-1 treatment effects were assessed by analyzing lung bacterial burdens and airway inflammation using an established model of chronic P. aeruginosa endobronchial infection in CF (?F508) mice. RTD-1 directly reduces metalloprotease activity, as well as inflammatory cytokine secretion from CF airway leukocyte and bronchial epithelial cells. Intrapulmonary safety, tolerability, and stability data support the aerosol administration route. RTD-1 reduced the bacterial lung burden, airway neutrophils, and inflammatory cytokines in CF mice with chronic P. aeruginosa lung infection. Collectively, these studies support further development of RTD-1 for treatment of CF airway disease.

| S-EPMC5527632 | biostudies-literature

Isolation, synthesis, and antimicrobial activities of naturally occurring theta-defensin isoforms from baboon leukocytes.

Project description:Theta-defensins are macrocyclic antimicrobial peptides that were previously isolated from leukocytes of a single species, the rhesus macaque. We now report the characterization of baboon theta-defensins (BTDs) expressed in bone marrow and peripheral blood leukocytes. Four cDNAs encoding theta-defensin precursors were characterized, allowing for the prediction of 10 theoretical theta-defensins (BTD-1 to BTD-10) produced by binary, head-to-tail splicing of nonapeptides excised from paired precursors. Five of the predicted theta-defensins were purified from baboon leukocytes, and synthetic versions of each were prepared. Anti-theta-defensin antibody localized the peptides in circulating neutrophils and monocytes and in immature and mature myeloid elements in bone marrow. Each of the BTDs possessed antimicrobial activity against bacterial and fungal test organisms in vitro. Peptide activities varied markedly despite a high degree of sequence conservation among the theta-defensins tested. Thus, baboons express numerous theta-defensins which appear to differentially contribute to host defense against diverse pathogens.

| S-EPMC2583559 | biostudies-literature

Beta-defensin 2 in the rhesus monkey (Macaca mulatta) and the long-tailed macaque (M. fascicularis).

Project description: Not available

| S-EPMC119968 | biostudies-literature

Rhesus macaque

Project description:Rhesus macaque Skin Microbiome raw sequence reads

| PRJNA675026 | ENA

Neutrophil recruitment and activation in decidua with intra-amniotic IL-1beta in the preterm rhesus macaque.

Project description:Chorioamnionitis, an infection/inflammation of the fetomaternal membranes, is frequently associated with preterm delivery. The mechanisms of inflammation in chorioamnionitis are poorly understood. We hypothesized that neutrophils recruited to the decidua would be the major producers of proinflammatory cytokines. We injected intra-amniotic (IA) interleukin 1beta (IL-1beta) at ?80% gestation in rhesus macaque monkeys, Macaca mulatta, delivered the fetuses surgically 24 h or 72 h after IA injections, and investigated the role of immune cells in the chorion-amnion decidua. IA IL-1beta induced a robust infiltration of neutrophils and significant increases of proinflammatory cytokines in the chorioamnion decidua at 24 h after exposure, with a subsequent decrease at 72 h. Neutrophils in the decidua were the major source of tumor necrosis factor alpha (TNFalpha) and IL-8. Interestingly, IA IL-1beta also induced a significant increase in anti-inflammatory indoleamine 2,3-dioxygenase (IDO) expression in the decidua neutrophils. The frequency of regulatory T cells (Tregs) and FOXP3 mRNA expression in the decidua did not change after IA IL-1beta injection. Collectively, our data demonstrate that in this model of sterile chorioamnionitis, the decidua neutrophils cause the inflammation in the gestational tissues but may also act as regulators to dampen the inflammation. These results help to understand the contribution of neutrophils to the pathogenesis of chorioamnionitis-induced preterm labor.

| S-EPMC4342792 | biostudies-literature

rhesus macaque viromes

Project description:Virome biogeography in the primate lower gastrointestinal tract

| PRJNA491509 | ENA