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1.
Int J Mol Sci ; 25(5)2024 Feb 24.
Article in English | MEDLINE | ID: mdl-38473905

ABSTRACT

Chronic kidney disease (CKD) affects > 10% of the global adult population and significantly increases the risk of cardiovascular disease (CVD), which remains the leading cause of death in this population. The development and progression of CVD-compared to the general population-is premature and accelerated, manifesting as coronary artery disease, heart failure, arrhythmias, and sudden cardiac death. CKD and CV disease combine to cause multimorbid cardiorenal syndrome (CRS) due to contributions from shared risk factors, including systolic hypertension, diabetes mellitus, obesity, and dyslipidemia. Additional neurohormonal activation, innate immunity, and inflammation contribute to progressive cardiac and renal deterioration, reflecting the strong bidirectional interaction between these organ systems. A shared molecular pathophysiology-including inflammation, oxidative stress, senescence, and hemodynamic fluctuations characterise all types of CRS. This review highlights the evolving paradigm and recent advances in our understanding of the molecular biology of CRS, outlining the potential for disease-specific therapies and biomarker disease detection.


Subject(s)
Cardio-Renal Syndrome , Cardiovascular Diseases , Heart Failure , Renal Insufficiency, Chronic , Humans , Chronic Disease , Renal Insufficiency, Chronic/complications , Inflammation/complications
2.
RMD Open ; 9(3)2023 08.
Article in English | MEDLINE | ID: mdl-37562858

ABSTRACT

OBJECTIVE: The prevalence of comorbid chronic kidney disease (CKD) and osteoarthritis (OA) is increasing globally. While sharing common risk factors, the mechanism and consequences of concurrent CKD-OA are unclear. The aims of the study were to develop a preclinical comorbid model, and to investigate the disease-modifying interactions. METHODS: Seventy (70) male 8-10 week-old C57BL/6 mice were subjected to 5/6 nephrectomy (5/6Nx)±destabilisation of medial meniscus (DMM) or sham surgery. OA pathology and CKD were assessed 12 weeks postinduction by blinded histology scoring, micro-CT, immunohistochemistry for osteoclast and matrix metalloproteinase (MMP)-13 activity, and serum analysis of bone metabolic markers. RESULTS: The 5/6Nx model recapitulated characteristic features of CKD, with renal fibrosis and deranged serum alkaline phosphatase, calcium and phosphate. There was no histological evidence of cartilage pathology induced by 5/6Nx alone, however, synovial MMP-13 expression and subchondral bone osteoclastic activity were increased (p<0.05), with accompanying reductions (p<0.05) in subchondral trabecular bone, bone volume and mineral density. DMM significantly (p<0.05) increased tibiofemoral cartilage damage, subchondral bone sclerosis, marginal osteophytes and synovitis, in association with increased cartilage and synovial MMP-13. DMM alone induced (p<0.05) renal fibrosis, proteinuria and increased (p<0.05) 5/6Nx-induced serum urea. However, DMM in 5/6Nx-mice resulted in significantly reduced (p<0.05) cartilage pathology and marginal osteophyte development, in association with reduced subchondral bone volume and density, and inhibition of 5/6Nx-induced subchondral bone osteoclast activation. CONCLUSION: This study assessed a world-first preclinical comorbid CKD-OA model. Our findings demonstrate significant bidirectional disease-modifying interaction between CKD and OA.


Subject(s)
Osteoarthritis , Osteophyte , Male , Mice , Humans , Animals , Matrix Metalloproteinase 13/metabolism , Mice, Inbred C57BL , Osteoarthritis/pathology , Disease Models, Animal , Osteophyte/pathology , Fibrosis
3.
Kidney Int ; 104(3): 492-507, 2023 09.
Article in English | MEDLINE | ID: mdl-37244471

ABSTRACT

Ischemia reperfusion injury is a common precipitant of acute kidney injury that occurs following disrupted perfusion to the kidney. This includes blood loss and hemodynamic shock, as well as during retrieval for deceased donor kidney transplantation. Acute kidney injury is associated with adverse long-term clinical outcomes and requires effective interventions that can modify the disease process. Immunomodulatory cell therapies such as tolerogenic dendritic cells remain a promising tool, and here we tested the hypothesis that adoptively transferred tolerogenic dendritic cells can limit kidney injury. The phenotypic and genomic signatures of bone marrow-derived syngeneic or allogeneic, Vitamin-D3/IL-10-conditioned tolerogenic dendritic cells were assessed. These cells were characterized by high PD-L1:CD86, elevated IL-10, restricted IL-12p70 secretion and a suppressed transcriptomic inflammatory profile. When infused systemically, these cells successfully abrogated kidney injury without modifying infiltrating inflammatory cell populations. They also provided protection against ischemia reperfusion injury in mice pre-treated with liposomal clodronate, suggesting the process was regulated by live, rather than reprocessed cells. Co-culture experiments and spatial transcriptomic analysis confirmed reduced kidney tubular epithelial cell injury. Thus, our data provide strong evidence that peri-operatively administered tolerogenic dendritic cells have the ability to protect against acute kidney injury and warrants further exploration as a therapeutic option. This technology may provide a clinical advantage for bench-to-bedside translation to affect patient outcomes.


Subject(s)
Acute Kidney Injury , Reperfusion Injury , Mice , Animals , Interleukin-10 , Acute Kidney Injury/prevention & control , Kidney , Dendritic Cells , Reperfusion Injury/prevention & control
4.
Mediators Inflamm ; 2023: 8387330, 2023.
Article in English | MEDLINE | ID: mdl-37101596

ABSTRACT

Theta- (θ-) defensins are pleiotropic host defense peptides with antimicrobial- and immune-modulating activities. Immune stimulation of cells with lipopolysaccharide (LPS, endotoxin) activates proinflammatory gene expression and cytokine secretion, both of which are attenuated by rhesus theta-defensin-1 (RTD-1) inhibition of NF-κB and MAP kinase pathways. Endotoxin tolerance is a condition that ensues when cells have an extended primary exposure to low levels of LPS, resulting in resistance to a subsequent LPS challenge. Recognition of LPS by Toll-like receptor-4 (TLR4) activates NF-κB, elevating levels of microRNA-146a (miR-146a), which targets IRAK1 and TRAF6 transcripts to reduce their protein levels and inhibits TLR signaling on secondary LPS stimulation. Here, we report that RTD-1 suppressed the expression of miR-146a and stabilized the IRAK1 protein in immune-stimulated, monocytic THP-1 cells. Cells that had primary exposure to LPS became endotoxin-tolerant, as evident from their failure to secrete TNF-α upon secondary endotoxin challenge. However, cells incubated with RTD-1 during the primary LPS stimulation secreted TNF-α after secondary LPS stimulation in an RTD-1 dose-dependent manner. Consistent with this, compared to the control treatment, cells treated with RTD-1 during primary LPS stimulation had increased NF-κB activity after secondary LPS stimulation. These results show that RTD-1 suppresses endotoxin tolerance by inhibiting the NF-κB pathway and demonstrates a novel inflammatory role for RTD-1 that is mediated by the downregulation of miR-146a during the innate immune response.


Subject(s)
MicroRNAs , NF-kappa B , NF-kappa B/metabolism , Lipopolysaccharides/pharmacology , Tumor Necrosis Factor-alpha , Endotoxin Tolerance , Defensins , Endotoxins , Interleukin-1 Receptor-Associated Kinases/genetics , Interleukin-1 Receptor-Associated Kinases/metabolism , MicroRNAs/genetics , MicroRNAs/metabolism
5.
Health Promot J Austr ; 34(1): 70-84, 2023 Feb.
Article in English | MEDLINE | ID: mdl-36088579

ABSTRACT

ISSUE ADDRESSED: Child and youth participation in physical activity (PA) is fundamental for healthy development and obesity prevention. Government policy requires schools to offer 150 minutes of PA each week, however compliance is low. Race around Australia (RAA) is a New South Wales (NSW) Department of Education, virtual PA program aimed at assisting schools in meeting the PA guidelines. METHODS: A pre- and post-intervention, quasi-experimental study was conducted using a mixed-methods approach comprising teacher interviews, a student questionnaire and a 1.6 kilometre (km) timed run. Data were collected from April to September 2021 among students and teachers in Grades 5 to 8, from 10 schools in NSW, Australia. RESULTS: The analytical sample included data from 918 students and 17 teachers. The RAA program was deemed feasible and acceptable in primary schools, whereas there were several systemic and intrapersonal barriers to implementation success for secondary schools. In primary schools, RAA increased PA opportunities and the 1.6 km timed runs revealed a statistically significant treatment by time effect in favour of the intervention group for cardiorespiratory fitness (-36.91 seconds, 95% CI [-63.14, -10.68], P = .006). CONCLUSIONS: RAA has demonstrated feasibility and potential efficacy in improving cardiorespiratory fitness. We recommend that program refinement be made to deliver an intervention that addresses the unique barriers of the secondary school setting through a multi-level ecological approach. SO WHAT?: Despite evident benefits, implementation of PA initiatives in the school setting reveals many challenges. Stronger consideration of the Health Promotion with Schools Framework is evidently needed.


Subject(s)
Exercise , Schools , Child , Adolescent , Humans , New South Wales , Feasibility Studies , Australia , Health Promotion/methods , School Health Services
6.
Front Cardiovasc Med ; 9: 868658, 2022.
Article in English | MEDLINE | ID: mdl-35669475

ABSTRACT

Heart and kidney failure often co-exist and confer high morbidity and mortality. The complex bi-directional nature of heart and kidney dysfunction is referred to as cardiorenal syndrome, and can be induced by acute or chronic dysfunction of either organ or secondary to systemic diseases. The five clinical subtypes of cardiorenal syndrome are categorized by the perceived primary precipitant of organ injury but lack precision. Traditional biomarkers such as serum creatinine are also limited in their ability to provide an early and accurate diagnosis of cardiorenal syndrome. Novel biomarkers have the potential to assist in the diagnosis of cardiorenal syndrome and guide treatment by evaluating the relative roles of implicated pathophysiological pathways such as hemodynamic dysfunction, neurohormonal activation, endothelial dysfunction, inflammation and oxidative stress, and fibrosis. In this review, we assess the utility of biomarkers that correlate with kidney and cardiac (dys)function, inflammation/oxidative stress, fibrosis, and cell cycle arrest, as well as emerging novel biomarkers (thrombospondin-1/CD47, glycocalyx and interleukin-1ß) that may provide prediction and prognostication of cardiorenal syndrome, and guide potential development of targeted therapeutics.

7.
Int J Mol Sci ; 23(3)2022 Jan 25.
Article in English | MEDLINE | ID: mdl-35163259

ABSTRACT

The extracellular matrix (ECM) and ECM-regulatory proteins mediate structural and cell-cell interactions that are crucial for embryonic cardiac development and postnatal homeostasis, as well as organ remodeling and repair in response to injury. These proteins possess a broad functionality that is regulated by multiple structural domains and dependent on their ability to interact with extracellular substrates and/or cell surface receptors. Several different cell types (cardiomyocytes, fibroblasts, endothelial and inflammatory cells) within the myocardium elaborate ECM proteins, and their role in cardiovascular (patho)physiology has been increasingly recognized. This has stimulated robust research dissecting the ECM protein function in human health and disease and replicating the genetic proof-of-principle. This review summarizes recent developments regarding the contribution of ECM to cardiovascular disease. The clear importance of this heterogeneous group of proteins in attenuating maladaptive repair responses provides an impetus for further investigation into these proteins as potential pharmacological targets in cardiac diseases and beyond.


Subject(s)
Cardiovascular Diseases/metabolism , Extracellular Matrix Proteins/metabolism , Extracellular Matrix/metabolism , Animals , Humans , Myocardium/metabolism
8.
Intern Med J ; 52(1): 130-133, 2022 Jan.
Article in English | MEDLINE | ID: mdl-35060291

ABSTRACT

Current practice guidelines recommend that 'low-risk' outpatients undergoing percutaneous native renal biopsy (PRB) are observed for 6-8 h to identify post-biopsy complications. We performed a retrospective review of 225 PRB procedures in low-risk outpatients who were observed for a 4-h period to determine the safety with regard to complication rate and timing. PRB was performed using a standardised protocol and under ultrasound guidance with a 16- or 18-gauge needle. Bleeding complications occurred in 7% (16/225) of patients, of which 88% (14/16) were detected within a 4-h period. The two undetected complications presented more than 72 h after the procedure. This suggests that a 4-h observation period may be safe and adequate in identifying the majority of patients who will experience significant complications in the first 24 h, with a potential saving of time and resources.


Subject(s)
Kidney , Outpatients , Biopsy/adverse effects , Biopsy/methods , Biopsy, Needle/adverse effects , Biopsy, Needle/methods , Humans , Kidney/diagnostic imaging , Kidney/pathology , Ultrasonography
9.
Health Promot J Austr ; 33(1): 202-215, 2022 Jan.
Article in English | MEDLINE | ID: mdl-33715238

ABSTRACT

BACKGROUND: Childhood obesity is a significant public health issue. Sugar-sweetened beverage (SSB) consumption contributes to this and adolescents are high consumers. This paper provides a descriptive overview of a school-based intervention to address this. METHODS: 61 secondary schools in New South Wales were randomised to receive a behavioural intervention (BI), a chilled water station (CWS), both interventions or neither (control). The BI was delivered through classroom lessons, school-based promotion and vaccination clinic. The CWS intervention included the installation of one CWS per school. Intervention effectiveness over time was assessed via student surveys at baseline, post-intervention and follow-up (individual-level outcomes), feedback from teachers and vaccination nurses, a school information survey, and remotely monitored CWS water usage (school-level outcomes). RESULTS: Teachers reported the BI was useful in teaching students about drinking water and negative consequences of SSBs. Nurses considered the post-vaccination waiting period a good opportunity to deliver health promotion messages. Students in this group showed statistically significant changes in knowledge about SSBs, dehydration effects and changes in daily SSB consumption (T1 23.18%; T3 18.20%). Positive feedback regarding CWSs was received with an increase in water consumption reported for students in this group (T1 86.15% to T3 89.66%) and a statistically significant increase in students carrying a water bottle to school and filling it observed. CONCLUSIONS: Both interventions were readily implemented with high levels of acceptability and impact on students' knowledge and SSB consumption. The study demonstrates how to promote water consumption in schools utilising two different interventions. SO WHAT?: Evidence regarding how to decrease SSB consumption amongst secondary school students has been strengthened.


Subject(s)
Pediatric Obesity , Sugar-Sweetened Beverages , Adolescent , Beverages , Child , Humans , Pediatric Obesity/prevention & control , Schools , Students
10.
Sci Rep ; 11(1): 23447, 2021 12 06.
Article in English | MEDLINE | ID: mdl-34873199

ABSTRACT

The emergence of infections by carbapenem resistant Enterobacteriaceae (CRE) pathogens has created an urgent public health threat, as carbapenems are among the drugs of last resort for infections caused by a growing fraction of multi-drug resistant (MDR) bacteria. There is global consensus that new preventive and therapeutic strategies are urgently needed to combat the growing problem of MDR bacterial infections. Here, we report on the efficacy of a novel macrocyclic peptide, minimized theta-defensin (MTD)-12813 in CRE sepsis. MTD12813 is a theta-defensin inspired cyclic peptide that is highly effective against CRE pathogens K. pneumoniae and E. coli in vivo. In mouse septicemia models, single dose administration of MTD12813 significantly enhanced survival by promoting rapid host-mediated bacterial clearance and by modulating pathologic cytokine responses, restoring immune homeostasis, and preventing lethal septic shock. The peptide lacks direct antibacterial activity in the presence of mouse serum or in peritoneal fluid, further evidence for its indirect antibacterial mode of action. MTD12813 is highly stable in biological matrices, resistant to bacterial proteases, and nontoxic to mice at dose levels 100 times the therapeutic dose level, properties which support further development of the peptide as a first in class anti-infective therapeutic.


Subject(s)
Anti-Bacterial Agents/pharmacology , Carbapenem-Resistant Enterobacteriaceae/drug effects , Drug Resistance, Multiple, Bacterial/drug effects , Escherichia coli/drug effects , Gram-Negative Bacterial Infections/drug therapy , Klebsiella pneumoniae/drug effects , Animals , Bacterial Infections/drug therapy , Carbapenems/pharmacology , Cytokines/metabolism , Drug Design , Female , Humans , Inflammation , Male , Mice , Mice, Inbred BALB C , Microbial Sensitivity Tests , Peptides/pharmacology , Phagocytosis , Sepsis/blood
11.
s.l; Harvard Business School; 2021.
Non-conventional in English | SDG | ID: biblio-1344580

ABSTRACT

We apply the product impact measurement framework of the Impact-Weighted Accounts Initiative (IWAI) in two competitor companies within the pharmaceuticals industry. We design a monetization methodology that allows us to calculate monetary impact estimates of accessible product provision and efficacy, among other factors. Our results indicate substantial differences in the impact that competitors have through their products. These differences demonstrate how impact reflects corporate strategy and informs decision-making on industry-specific areas.(AU)


Subject(s)
Competitive Bidding , Decision Making , Drug Industry/economics , Health Impact Assessment
12.
s.l; Harvard Business School; 2020.
Non-conventional in English | SDG | ID: biblio-1344529

ABSTRACT

While there has been significant progress in the measurement of an organization's environmental and social impacts from its operations, metrics to evaluate the impact of products once they come to market lag far behind. In this paper, we provide a framework for systematic measurement of product impact in monetary terms and delve into the rationale for the framework's seven elements. We then apply the whole framework to two competitor companies to show the feasibility of measuring product impact and the actionability of the framework. We indicate the value of impactweighted financial statement analysis with examples of insights enabled by industry-wide product impact measurement. We see our results as a first step, rather than a definitive answer, towards more systematic measurement of product impact in monetary terms that can then be reflected in financial statements with the purpose of creating impact-weighted financial accounts.(AU)


Subject(s)
Environment , Health Governance/economics , Accounting/economics
13.
s.l; Harvard Business School; 2020.
Non-conventional in English | SDG | ID: biblio-1344564

ABSTRACT

We apply the product impact measurement framework of the Impact-Weighted Accounts Initiative (IWAI) in two competitor companies within the airlines industry. We design a monetization methodology that allows us to calculate monetary impact estimates of fare affordability, timeliness and gate control, among other factors. Our results indicate substantial differences in the impact that competitors have through their products. These differences demonstrate how impact reflects corporate strategy and informs decision-making on industry-specific areas, including airline route structure choices.(AU)


Subject(s)
Aviation/economics , Aviation/organization & administration , Competitive Bidding , Industry
14.
s.l; Harvard Business School; 2020.
Non-conventional in English | SDG | ID: biblio-1344568

ABSTRACT

We apply the product impact measurement framework of the Impact-Weighted Accounts Initiative (IWAI) in two competitor companies within the consumer-packaged goods industry. We design a methodology that allows us to calculate monetary impact estimates on customer health, access and affordability of products and recyclability, among other factors. Our results indicate substantial differences in the impact that competitors have through their products. These differences demonstrate how impact measures reflect business strategy choices and informs decision-making on industry-specific areas, including food reformulation and product placement.(AU)


Subject(s)
Food Industry/economics , Decision Making , Eating , Competitive Bidding
15.
s.l; Harvard Business School; 2020.
Non-conventional in English | SDG | ID: biblio-1344573

ABSTRACT

We apply the product impact measurement framework of the Impact-Weighted Accounts Initiative (IWAI) in two competitor companies within the oil and gas industry. We design a monetization methodology that allows us to calculate monetary product impact estimates of natural gas provision to emerging markets, energy provided, and emissions created. Our results indicate differences in the impact that competitors have through their products. These differences demonstrate how impact reflects corporate strategy and informs decision-making on industryspecific areas.(AU)


Subject(s)
Petroleum Pollution/economics , Decision Making , Oil and Gas Industry/economics , Competitive Bidding
16.
Physiol Genomics ; 51(12): 657-667, 2019 12 01.
Article in English | MEDLINE | ID: mdl-31762409

ABSTRACT

Rhesus theta defensin-1 (RTD-1), a macrocyclic immunomodulatory host defense peptide from Old World monkeys, is therapeutic in pristane-induced arthritis (PIA) in rats, a model of rheumatoid arthritis (RA). RNA-sequence (RNA-Seq) analysis was used to interrogate the changes in gene expression in PIA rats, which identified 617 differentially expressed genes (DEGs) in PIA synovial tissue of diseased rats. Upstream regulator analysis showed upregulation of gene expression pathways regulated by TNF, IL1B, IL6, proinflammatory cytokines, and matrix metalloproteases (MMPs) involved in RA. In contrast, ligand-dependent nuclear receptors like the liver X-receptors NR1H2 and NR1H3 and peroxisome proliferator-activated receptor gamma (PPARG) were downregulated in arthritic synovia. Daily RTD-1 treatment of PIA rats for 1-5 days following disease presentation modulated 340 of the 617 disease genes, and synovial gene expression in PIA rats treated 5 days with RTD-1 closely resembled the gene signature of naive synovium. Systemic RTD-1 inhibited proinflammatory upstream regulators such as TNF, IL1, and IL6 and activated antiarthritic ligand-dependent nuclear receptor pathways, including PPARG, NR1H2, and NR1H3, that were suppressed in untreated PIA rats. RTD-1 also inhibited proinflammatory responses in IL-1ß-stimulated human RA fibroblast-like synoviocytes (FLS) in vitro and diminished expression of human orthologs of disease genes that are induced in rat PIA synovium. Thus, the antiarthritic mechanisms of systemic RTD-1 include homeostatic regulation of arthritogenic gene networks in a manner that correlates temporally with clinical resolution of rat PIA.


Subject(s)
Arthritis, Rheumatoid/drug therapy , Fibroblasts/metabolism , Inflammation Mediators/antagonists & inhibitors , Peptides, Cyclic/pharmacology , Peptides, Cyclic/therapeutic use , Synovial Membrane/metabolism , Transcriptome/drug effects , alpha-Defensins/pharmacology , alpha-Defensins/therapeutic use , Animals , Arthritis, Rheumatoid/chemically induced , Arthritis, Rheumatoid/metabolism , Cell Line , Cercopithecidae , Cytokines/genetics , Disease Models, Animal , Female , Humans , Immunosuppressive Agents/pharmacology , RNA-Seq , Rats , Synoviocytes/metabolism , Terpenes/pharmacology , Up-Regulation
17.
PLoS One ; 12(11): e0187868, 2017.
Article in English | MEDLINE | ID: mdl-29145473

ABSTRACT

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-1ß 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.


Subject(s)
Arthritis, Rheumatoid/prevention & control , Defensins/pharmacology , Animals , Arthritis, Rheumatoid/immunology , Macaca mulatta , Male , Rats , Rats, Sprague-Dawley
18.
J Leukoc Biol ; 98(6): 1061-70, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26269197

ABSTRACT

θ-Defensins are pleiotropic, macrocyclic peptides that are expressed uniquely in Old World monkeys. The peptides are potent, broad-spectrum microbicides that also modulate inflammatory responses in vitro and in animal models of viral infection and polymicrobial sepsis. θ-Defensins suppress proinflammatory cytokine secretion by leukocytes stimulated with diverse Toll-like receptor (TLR) ligands. Studies were performed to delineate anti-inflammatory mechanisms of rhesus θ-defensin 1 (RTD-1), the most abundant θ-defensin isoform in macaque granulocytes. RTD-1 reduced the secretion of tumor necrosis factor-α (TNF-α), interleukin (IL)-1ß, and IL-8 in lipopolysaccharide (LPS)-stimulated human blood monocytes and THP-1 macrophages, and this was accompanied by inhibition of nuclear factor κB (NF-κB) activation and mitogen-activated protein kinase (MAPK) pathways. Peptide inhibition of NF-κB activation occurred following stimulation of extracellular (TLRs 1/2 and 4) and intracellular (TLR9) receptors. Although RTD-1 did not inhibit MAPK in unstimulated cells, it induced phosphorylation of Akt in otherwise untreated monocytes and THP-1 cells. In the latter, this occurred within 10 min of RTD-1 treatment and produced a sustained elevation of phosphorylated Akt (pAkt) for at least 4 h. pAkt is a negative regulator of MAPK and NF-κB activation. RTD-1 inhibited IκBα degradation and p38 MAPK phosphorylation, and stimulated Akt phosphorylation in LPS-treated human primary monocytes and THP-1 macrophages. Specific inhibition of phosphatidylinositol 3-kinase (PI3K) blocked RTD-1-stimulated Akt phosphorylation and reversed the suppression of NF-κB activation by the peptide. These studies indicate that the anti-inflammatory properties of θ-defensins are mediated by activation of the PI3K/Akt pathway and suppression of proinflammatory signals in immune-stimulated cells.


Subject(s)
Cytokines/immunology , Gene Expression Regulation/immunology , MAP Kinase Signaling System/immunology , Macrophages/immunology , Monocytes/immunology , NF-kappa B/immunology , Peptides, Cyclic/immunology , alpha-Defensins/immunology , Cell Line, Tumor , Female , Gene Expression Regulation/drug effects , Humans , Lipopolysaccharides/pharmacology , MAP Kinase Signaling System/drug effects , Macrophages/cytology , Male , Monocytes/cytology , Peptides, Cyclic/pharmacology , Phosphatidylinositol 3-Kinases/immunology , Phosphorylation/drug effects , Phosphorylation/immunology , Proto-Oncogene Proteins c-akt/immunology , Toll-Like Receptors/agonists , Toll-Like Receptors/immunology , alpha-Defensins/pharmacology , p38 Mitogen-Activated Protein Kinases/immunology
19.
PLoS One ; 7(12): e51337, 2012.
Article in English | MEDLINE | ID: mdl-23236475

ABSTRACT

Theta-defensins (θ-defensins) are macrocyclic antimicrobial peptides expressed in leukocytes of Old World monkeys. The peptides are broad spectrum microbicides in vitro and numerous θ-defensin isoforms have been identified in granulocytes of rhesus macaques and Olive baboons. Several mammalian α- and ß-defensins, genetically related to θ-defensins, have proinflammatory and immune-activating properties that bridge innate and acquired immunity. In the current study we analyzed the immunoregulatory properties of rhesus θ-defensins 1-5 (RTDs 1-5). RTD-1, the most abundant θ-defensin in macaques, reduced the levels of TNF, IL-1α, IL-1ß, IL-6, and IL-8 secreted by blood leukocytes stimulated by several TLR agonists. RTDs 1-5 suppressed levels of soluble TNF released by bacteria- or LPS-stimulated blood leukocytes and THP-1 monocytes. Despite their highly conserved conformation and amino acid sequences, the anti-TNF activities of RTDs 1-5 varied by as much as 10-fold. Systemically administered RTD-1 was non-toxic for BALB/c mice, and escalating intravenous doses were well tolerated and non-immunogenic in adult chimpanzees. The peptide was highly stable in serum and plasma. Single dose administration of RTD-1 at 5 mg/kg significantly improved survival of BALB/c mice with E. coli peritonitis and cecal ligation-and-puncture induced polymicrobial sepsis. Peptide treatment reduced serum levels of several inflammatory cytokines/chemokines in bacteremic animals. Collectively, these results indicate that the anti-inflammatory properties of θ-defensins in vitro and in vivo are mediated by the suppression of numerous proinflammatory cytokines and blockade of TNF release may be a primary effect.


Subject(s)
Defensins/immunology , Protein Isoforms/immunology , Sepsis/drug therapy , Sepsis/immunology , Animals , Chromatography, High Pressure Liquid , Cytokines/blood , Defensins/administration & dosage , Defensins/genetics , Defensins/therapeutic use , Dose-Response Relationship, Drug , Mice , Mice, Inbred BALB C , Neutralization Tests , Pan troglodytes , Protein Isoforms/administration & dosage , Protein Isoforms/genetics , Protein Isoforms/therapeutic use
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