Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 25
Filter
Add more filters










Publication year range
1.
Sci Rep ; 14(1): 7368, 2024 03 28.
Article in English | MEDLINE | ID: mdl-38548826

ABSTRACT

The seasonal outbreaks of Mpox continue in most parts of West and Central Africa. In the past year, Nigeria had the highest number of reported cases. Here, we used the PRISMA guidelines to carry out a systematic review and meta-analysis of available evidence on Mpox in Nigeria to assess the prevalence, transmission pattern, diagnostic approach, and other associated factors useful for mitigating the transmission of the disease. All relevant observational studies in PubMed/MEDLINE, Embase, AJOL, Web of Science, Scopus and Google Scholar on Mpox in Nigeria were assessed within the last fifty years (1972 to 2022). In all, 92 relevant articles were retrieved, out of which 23 were included in the final qualitative analysis. Notably, most of the cases of Mpox in Nigeria were from the southern part of the country. Our findings showed a progressive spread from the southern to the northern region of the country. We identified the following factors as important in the transmission of Mpox in Nigeria; poverty, lack of basic healthcare facilities, and risk of exposure through unsafe sexual practices. Our findings reiterate the need to strengthen and expand existing efforts as well as establish robust multi-sectoral collaboration to understand the dynamics of Mpox Nigeria.


Subject(s)
Mpox (monkeypox) , Humans , Nigeria/epidemiology , Disease Outbreaks , Health Facilities , MEDLINE
2.
Poult Sci ; 103(2): 103318, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38064884

ABSTRACT

Backyard poultry flocks that employ heritage breeds of chicken play a crucial role in the maintenance of poultry pathogens of economic and zoonotic importance. This study examined innate immunity to viral pathogens in heritage chicken breeds using a model of viral double-stranded RNA (dsRNA). Following intraperitoneal injection of high molecular weight (HMW) -poly(I:C)/Lyovec into 4-wk-old chicks, we evaluated gene expression in peripheral blood mononuclear cells (PBMCs) and splenocytes. There was a significant difference across breeds in the expression of IL-4, IL-12p40, IFNγ, and B-cell activating factor (BAFF) in the spleen. In PBMCs, a significant difference in IFN-α expression was seen across breeds. Approximately 57% of IFN-α transcripts in PBMCs was explained by levels of expression of MDA5 transcripts. Using flow cytometry, we showed that only monocytes/macrophages (KUL01+ cells) expressed the scavenger receptor CD163. Regression analysis showed that 42% of fold change in CD163 expression on PBMCs was explained by breed (P < 0.0004). In general, breeds that responded to HMW-poly(I:C) by showing higher upregulation of IFNγ, IL-1ß, and IL-12p40 transcripts in the spleen, and higher IFNα transcripts in peripheral blood, expressed less CD163 on blood monocytes. These findings suggest a genetic basis for the response of chickens to double-stranded RNA. Surface expression of the scavenger receptor CD163 in PBMCs following injection of high molecular weight poly(I:C) may be a rapid method to select chickens for breeding based on innate immune response to viral dsRNA.


Subject(s)
Chickens , Leukocytes, Mononuclear , Animals , Chickens/genetics , RNA, Double-Stranded , Interleukin-12 Subunit p40 , Immunity, Innate/genetics , Poly I-C/pharmacology , Receptors, Scavenger
3.
Acta Trop ; 250: 107108, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38145830

ABSTRACT

Parvoviruses are a major cause of haemorrhagic gastroenteritis, leukopenia and high mortality in cats and dogs. In this study, the presence and genetic characteristics of parvoviruses circulating among cats in Nigeria are reported. Faecal samples of stray cats from live animal markets in southwestern (Oyo and Osun States) and north-central (Kwara State) Nigeria were screened for the presence of parvoviral DNA using a qPCR. Positive samples were further characterized using a qPCR based on minor groove binder probes. Overall, 85/102 (83.3 %) stray cats tested positive for feline panleukopenia virus (FPV) DNA and one cat was co-infected with canine parvovirus-2 type a. Sequence analysis of the complete capsid region of 15 Nigerian FPV strains revealed that they were up to 99.9 % similar to the American reference strain FPV-b at the nucleotide level, and three of them presented amino acid mutations in key capsid residues. This is the first report of identification and molecular characterization of FPV strains in cats in Nigeria. The high prevalence of the virus emphasizes the need for constant surveillance of the circulation of parvoviruses in Nigeria and underscores the need to deploy an effective vaccination strategy.


Subject(s)
Feline Panleukopenia , Parvovirus, Canine , Parvovirus , Animals , Cats , Dogs , Feline Panleukopenia/epidemiology , Parvovirus, Canine/genetics , Nigeria/epidemiology , Phylogeny , Parvovirus/genetics , Feline Panleukopenia Virus/genetics , DNA
4.
Sci Rep ; 13(1): 20855, 2023 11 27.
Article in English | MEDLINE | ID: mdl-38012226

ABSTRACT

Lassa fever (LF) is prevalent in many West African countries, including Nigeria. Efforts to combat LF have primarily focused on rural areas where interactions between rodents and humans are common. However, recent studies indicate a shift in its occurrence from rural to urban areas. We analysed secondary data of reported LF outbreaks from 2017 to 2021 in Ondo State, Nigeria to identify the distribution pattern, ecological variations, and other determinants of disease spread from the ward level using nearest neighbour statistics and regression analysis. Data utilised include LF incidence, ecological variables involving population, nighttime light intensity, vegetation, temperature, market presence, road length, and building area coverage. ArcGIS Pro 3.0 software was employed for spatial analysis. Results revealed spatio-temporal clustering of LF incidents between 2017 and 2021, with an increasing trend followed by a decline in 2021. All wards in Owo Local Government Area were identified as LF hotspots. The ecological variables exhibited significant correlations with the number of LF cases in the wards, except for maximum temperature. Notably, these variables varied significantly between wards with confirmed LF and those without. Therefore, it is important to prioritise strategies for mitigating LF outbreaks in urban areas of Nigeria and other LF-endemic countries.


Subject(s)
Lassa Fever , Humans , Animals , Lassa Fever/epidemiology , Nigeria/epidemiology , Incidence , Africa, Western , Disease Outbreaks , Rodentia , Lassa virus
5.
Vaccines (Basel) ; 11(10)2023 Oct 03.
Article in English | MEDLINE | ID: mdl-37896964

ABSTRACT

Viral double-stranded RNA (dsRNA) interacts with Retinoic-acid-inducible-gene-1 (RIG-1)-like receptors (RLRs) to induce type 1 interferons. Melanoma-derived-antigen-5 (MDA-5), an RLR, but not RIG-1, is found in chickens. Ducks express both RIG-1 and MDA-5, a possible cause of differences in susceptibility to influenza virus infection between chickens and ducks. Using the HD11 chicken macrophage cell line and an RT2 Profiler PCR-array system, we showed that high-molecular-weight poly(I:C), HMW-poly(I:C), upregulates CCL4, interferon-gamma, interleukin-1, and interleukin-6 mRNA transcripts. HMW-poly(I:C), an in vitro surrogate of long dsRNA species, also induces the upregulation of IL-12B and B cell activating factor (BAFF). Conversely, low-molecular-weight poly(I:C), LMW-poly(I:C) did not induce a distinct cytokine expression pattern. Nonetheless, co-transfection of LMW and HMW-poly(I:C) significantly reduced the upregulation of IL12B and BAFF by HMW-poly(I:C). These findings support previous studies that found no expression of RIG-1, a receptor for short dsRNA species, in chicken cells. Surprisingly, however, our data suggested that in the absence of RIG-1 in chicken macrophages, short dsRNA species may inhibit macrophage-mediated B cell development and survival by modulating the expression of BAFF without significantly reducing type 1 interferon response.

6.
J Vet Diagn Invest ; 35(5): 507-513, 2023 Sep.
Article in English | MEDLINE | ID: mdl-37317863

ABSTRACT

We report here a transiently culturable oomycete pathogen isolated from a pyogranulomatous tail mass in a cat. The organism was morphologically and genetically distinct from Lagenidium and Pythium species. Following next-generation sequencing (NGS) and assembly of contigs, initial phylogenetic analysis using fragments of the cox1 mitochondrial gene identified this specimen as Paralagenidium sp. after nucleotide alignments with sequences obtained from the Barcode of Life Data System (BOLD). However, further analysis of a concatenation of 13 different mitochondrial genes showed that this organism is unique and different from all known oomycetes. A negative PCR result using primers targeting known oomycete pathogens may not be enough to rule out oomycosis in a suspected case. Additionally, the use of a single gene to classify oomycetes may produce misleading results. The advent of metagenomic sequencing and NGS provides a unique opportunity to further explore the diversity of oomycetes as plant and animal pathogens beyond the current capabilities of global barcoding projects that are based on partial genomic sequences.


Subject(s)
Pythium , Cats , Animals , Phylogeny , Pythium/genetics , Genomics
8.
Vet Clin Pathol ; 51(1): 112-114, 2022 Mar.
Article in English | MEDLINE | ID: mdl-35122286

ABSTRACT

A 10-year-old, neutered male, indoor/outdoor domestic shorthair cat was presented for a mass on the right front paw. The mass was treated as an abscess, and despite initial resolution, the mass recurred and ruptured approximately 1 month later. This mass successfully resolved with intense management as an open wound. Several days later, the cat developed vomiting and inappetence, and a new mass was noted on the lateral aspect of the right rear limb. Aspirates from the new mass were submitted for cytologic evaluation and bacterial cultures. Anaerobic and aerobic bacterial cultures were negative. Cytologic evaluation revealed septic neutrophilic inflammation with small rod, cocci, curved, and ring forms of bacteria seen, and Mycoplasma spp. infection was suspected based on the morphology of the bacteria. Polymerase chain reaction followed by gene sequencing revealed 86% similarity for Mycoplasma elephantis. The cat was treated with a fluoroquinolone antibiotic and clinically improved, with resolution of the abscess. This case highlights the importance of recognizing the morphologic appearance of Mycoplasma spp. on cytologic examination to help guide additional testing choices and therapeutic planning.


Subject(s)
Cat Diseases , Mycoplasma Infections , Mycoplasma , Abscess/diagnosis , Abscess/drug therapy , Abscess/veterinary , Animals , Cat Diseases/diagnosis , Cat Diseases/drug therapy , Cats , Male , Mycoplasma/genetics , Mycoplasma Infections/diagnosis , Mycoplasma Infections/drug therapy , Mycoplasma Infections/veterinary , Polymerase Chain Reaction/veterinary
9.
Vet Pathol ; 59(1): 91-99, 2022 01.
Article in English | MEDLINE | ID: mdl-34521286

ABSTRACT

Severe equine asthma (SEA) is a common, debilitating lower airway inflammatory disorder of older horses. Alveolar macrophages (AMs) survey inhaled particulates from barn sources causing them to switch from an anti-inflammatory to a proinflammatory phenotype, resulting in neutrophil recruitment to the lung. This proinflammatory switch may contribute to the development and prolongation of SEA. Validated antibodies to identify the cells involved in the pathogenesis of SEA are lacking. In this study, monoclonal antibodies against CD90, CD163, and CD206 were tested for reactivity with equine leukocytes by immunocytochemistry and flow cytometry. A multi-color flow cytometric assay was developed to identify leukocytes in equine bronchoalveolar lavage fluid (BALF). Four control and 4 SEA-susceptible horses had BALF collected before and after a 48-hour moldy hay challenge. Antibodies against CD90 uniquely labeled equine neutrophils, and antibodies against CD163 and CD206 identified equine macrophages. Postchallenge AM surface expression of CD163 increased in both groups of horses, but the increase was statistically significant in only the SEA-susceptible group (P = .02). The surface expression of CD206 on AMs increased significantly in the SEA-susceptible group (P = .03) but was unchanged in the control group (P = .5). Increased expression of CD163 and CD206 during exacerbation of SEA suggested an association between AM phenotype and lung inflammation. However, functions of AMs in the pathogenesis of SEA remain to be elucidated.


Subject(s)
Asthma , Horse Diseases , Animals , Asthma/veterinary , Bronchoalveolar Lavage Fluid , Flow Cytometry/veterinary , Horses , Macrophages, Alveolar
10.
Viruses ; 13(7)2021 07 09.
Article in English | MEDLINE | ID: mdl-34372536

ABSTRACT

Equine rotavirus group A (ERVA) is one of the most common causes of foal diarrhea. Starting in February 2021, there was an increase in the frequency of severe watery to hemorrhagic diarrhea cases in neonatal foals in Central Kentucky. Diagnostic investigation of fecal samples failed to detect evidence of diarrhea-causing pathogens including ERVA. Based on Illumina-based metagenomic sequencing, we identified a novel equine rotavirus group B (ERVB) in fecal specimens from the affected foals in the absence of any other known enteric pathogens. Interestingly, the protein sequence of all 11 segments had greater than 96% identity with group B rotaviruses previously found in ruminants. Furthermore, phylogenetic analysis demonstrated clustering of the ERVB with group B rotaviruses of caprine and bovine strains from the USA. Subsequent analysis of 33 foal diarrheic samples by RT-qPCR identified 23 rotavirus B-positive cases (69.69%). These observations suggest that the ERVB originated from ruminants and was associated with outbreaks of neonatal foal diarrhea in the 2021 foaling season in Kentucky. Emergence of the ruminant-like group B rotavirus in foals clearly warrants further investigation due to the significant impact of the disease in neonatal foals and its economic impact on the equine industry.


Subject(s)
Horse Diseases/virology , Horses/virology , Rotavirus/pathogenicity , Animals , Capsid Proteins/genetics , Diarrhea/etiology , Diarrhea/virology , Disease Outbreaks/veterinary , Feces/virology , Kentucky , Phylogeny , RNA, Viral/genetics , Real-Time Polymerase Chain Reaction/methods , Rotavirus/classification , Rotavirus Infections/veterinary
11.
J Vet Diagn Invest ; 33(1): 167-169, 2021 Jan.
Article in English | MEDLINE | ID: mdl-33164720

ABSTRACT

Canine distemper virus (CDV) has long been recognized as a cause of myocarditis; however, cases of myocarditis caused by naturally acquired CDV infection have been reported only rarely in dogs. We describe here our retrospective study of naturally acquired systemic CDV infection in 4 dogs, 4-7 wk old, that had myocarditis, with myocardial necrosis and fibrosis. One of the 4 dogs had intracytoplasmic eosinophilic inclusion bodies in cardiomyocytes. Other lesions included bronchointerstitial pneumonia (4 of 4), necrotizing hepatitis (2 of 4), splenic lymphoid necrosis (2 of 4), encephalitis (1 of 3; brain was not submitted in 1 case), and necrotizing gastroenteritis (1 of 4). The presence of CDV in the heart was confirmed by immunohistochemistry in all 4 dogs.


Subject(s)
Distemper Virus, Canine/physiology , Distemper/complications , Dog Diseases/pathology , Myocarditis/veterinary , Animals , Distemper/virology , Dog Diseases/virology , Dogs , Heart/virology , Myocarditis/pathology , Myocarditis/virology , Retrospective Studies
12.
Vaccines (Basel) ; 8(4)2020 Nov 16.
Article in English | MEDLINE | ID: mdl-33207583

ABSTRACT

To optimize the public health response to coronavirus disease 2019 (COVID-19), we must first understand the antibody response to individual proteins on the severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) and the antibody's cross reactivity to other coronaviruses. Using a panel of 37 convalescent COVID-19 human serum samples, we showed that the magnitude and specificity of responses varied across individuals, independent of their reactivity to seasonal human coronaviruses (HCoVs). These data suggest that COVID-19 vaccines will elicit primary humoral immune responses in naïve individuals and variable responses in those previously exposed to SARS-CoV-2. Unlike the limited cross-coronavirus reactivities in humans, serum samples from 96 dogs and 10 cats showed SARS-CoV-2 protein-specific responses focused on non-S1 proteins. The correlation of this response with those to other coronaviruses suggests that the antibodies are cross-reactive and generated to endemic viruses within these hosts, which must be considered in seroepidemiologic studies. We conclude that substantial variation in antibody generation against coronavirus proteins will influence interpretations of serologic data in the clinical and veterinary settings.

13.
J Leukoc Biol ; 108(1): 169-176, 2020 07.
Article in English | MEDLINE | ID: mdl-32450617

ABSTRACT

Respiratory syncytial virus (RSV) is associated with bronchiolitis in infancy and the later development of asthma. Research on RSV in vitro requires preparation of a purified RSV stock. The objective for this work was to develop best methods for RSV purification, while monitoring the samples for potential contaminating proinflammatory mediators. Using polyethylene glycol concentration, and sucrose-gradient ultracentrifugation, we collected samples at each step of purification and measured the values of RSV titer, total protein (µg/mL), and proinflammatory cytokines (ELISA). We analyzed the efficacy of each step in the purification procedure. In so doing, we also determined that despite optimal purification methods, a well-known chemokine in the field of allergic disease, CCL5 (RANTES), persisted within the virus preparations, whereas other cytokines did not. We suggest that researchers should be aware that CCL5 appears to co-purify with RSV. Despite reasonable purification methods, a significant level of CCL5 (RANTES) persists in the virus preparation. This is relevant to the study of RSV-induced allergic disease.


Subject(s)
Chemokine CCL5/metabolism , Respiratory Syncytial Virus, Human/metabolism , Sucrose/chemistry , Amino Acid Sequence , Cell Line , Chemokine CCL5/chemistry , Humans , Image Processing, Computer-Assisted , Respiratory Syncytial Virus, Human/isolation & purification , Ultracentrifugation , Viral Proteins/chemistry , Viral Proteins/metabolism , Virion/metabolism
14.
Immunology ; 153(3): 368-379, 2018 03.
Article in English | MEDLINE | ID: mdl-28940416

ABSTRACT

Given the pivotal roles that CD4+ T cell imbalance plays in human immune disorders, much interest centres on better understanding influences that regulate human helper T-cell subset dominance in vivo. Here, using primary CD4+ T cells and short-term T helper type 1 (Th1) and Th2-like lines, we investigated roles and mechanisms by which neurotransmitter receptors may influence human type 1 versus type 2 immunity. We hypothesized that N-methyl-d-aspartate receptors (NMDA-R), which play key roles in memory and learning, can also regulate human CD4+ T cell function through induction of excitotoxicity. Fresh primary CD4+ T cells from healthy donors express functional NMDA-R that are strongly up-regulated upon T cell receptor (TCR) mediated activation. Synthetic and physiological NMDA-R agonists elicited Ca2+ flux and led to marked inhibition of type 1 but not type 2 or interleukin-10 cytokine responses. Among CD4+ lines, NMDA and quinolinic acid preferentially reduced cytokine production, Ca2+ flux, proliferation and survival of Th1-like cells through increased induction of cell death whereas Th2-like cells were largely spared. Collectively, the findings demonstrate that (i) NMDA-R is rapidly up-regulated upon CD4+ T cell activation in humans and (ii) Th1 versus Th2 cell functions such as proliferation, cytokine production and cell survival are differentially affected by NMDA-R agonists. Differential cytokine production and proliferative capacity of Th1 versus Th2 cells is attributable in part to increased physiological cell death among fully committed Th1 versus Th2 cells, leading to increased Th2-like dominance. Hence, excitotoxicity, beyond its roles in neuronal plasticity, may contribute to ongoing modulation of human T cell responses.


Subject(s)
Neurotransmitter Agents/metabolism , Receptors, N-Methyl-D-Aspartate/metabolism , T-Lymphocytes, Helper-Inducer/metabolism , Th2 Cells/metabolism , CD4-Positive T-Lymphocytes/immunology , CD4-Positive T-Lymphocytes/metabolism , Cell Death/immunology , Cell Line , Cell Proliferation/physiology , Cytokines/immunology , Cytokines/metabolism , Humans , Interleukin-10/immunology , Lymphocyte Activation/immunology , Neurotransmitter Agents/immunology , Receptors, Antigen, T-Cell/immunology , Receptors, N-Methyl-D-Aspartate/immunology , T-Lymphocytes, Helper-Inducer/immunology , Th1 Cells/immunology , Th2 Cells/immunology , Up-Regulation/immunology
15.
J Clin Cell Immunol ; 7(6)2016 Dec.
Article in English | MEDLINE | ID: mdl-28149670

ABSTRACT

Cholecystokinin (CCK) is a neuropeptide that affects growth rate in chickens by regulating appetite. CCK peptides exert their function by binding to two identified receptors, CCKAR and CCKBR in the GI tract and the brain, respectively, as well as in other organs. In mammals, CCK/CCKAR interactions affect a number of immunological parameters, including regulation of lymphocytes and functioning of monocytes. Thus, food intake and growth can potentially be altered by infection and the resulting inflammatory immune response. It is uncertain, however, whether chicken express CCKAR in immune organs and cells, and, if so, whether CCKAR expression is regulated by pathogen derived inflammatory stimuli. Herein, we identify expression of CCKAR protein in chicken peripheral blood mononuclear cells (PBMC) including monocytes, and expression of the CCKAR gene in PBMC, thymus, bursa, and spleen, in selected commercial and pure chicken breeds. Further, stimulation with various types of E. coli heat-labile enterotoxins or lipopolysaccharide significantly regulated expression of CCKAR on monocytes in the different breeds. Ligation of CCKAR with antibodies in PBMC induced mobilization of Ca2+, indicating that CCKAR is signal competent. Injection with polyinosinic: polycytidylic acid (poly I:C), a synthetic analogue of double stranded viral RNA that binds Toll-Like Receptor-3 (TLR3), also regulated gene expressions of CCKAR and proinflammatory cytokines, in the different breeds. Interestingly, variations in the expression levels of proinflammatory cytokines in the different breeds were highly correlated with CCKAR expression levels. Taken together, these findings indicate that the physiological function of CCKAR in the chicken is tightly regulated in immune organs and cells by external inflammatory stimuli, which in turn regulate growth. This is the first report CCKAR expression in immune organs and cells, in any species, and the initial observation that CCKAR is regulated by inflammatory stimuli associated with bacterial and viral infection.

16.
Immunology ; 144(4): 641-8, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25346443

ABSTRACT

Degranulation from eosinophils in response to secretagogue stimulation is a regulated process that involves exocytosis of granule proteins through specific signalling pathways. One potential pathway is dependent on cyclin-dependent kinase 5 (Cdk5) and its effector molecules, p35 and p39, which play a central role in neuronal cell exocytosis by phosphorylating Munc18, a regulator of SNARE binding. Emerging evidence suggests a role for Cdk5 in exocytosis in immune cells, although its role in eosinophils is not known. We sought to examine the expression of Cdk5 and its activators in human eosinophils, and to assess the role of Cdk5 in eosinophil degranulation. We used freshly isolated human eosinophils and analysed the expression of Cdk5, p35, p39 and Munc18c by Western blot, RT-PCR, flow cytometry and immunoprecipitation. Cdk5 kinase activity was determined following eosinophil activation. Cdk5 inhibitors were used (roscovitine, AT7519 and small interfering RNA) to determine its role in eosinophil peroxidase (EPX) secretion. Cdk5 was expressed in association with Munc18c, p35 and p39, and phosphorylated following human eosinophil activation with eotaxin/CCL11, platelet-activating factor, and secretory IgA-Sepharose. Cdk5 inhibitors (roscovitine, AT7519) reduced EPX release when cells were stimulated by PMA or secretory IgA. In assays using small interfering RNA knock-down of Cdk5 expression in human eosinophils, we observed inhibition of EPX release. Our findings suggest that in activated eosinophils, Cdk5 is phosphorylated and binds to Munc18c, resulting in Munc18c release from syntaxin-4, allowing SNARE binding and vesicle fusion, with subsequent eosinophil degranulation. Our work identifies a novel role for Cdk5 in eosinophil mediator release by agonist-induced degranulation.


Subject(s)
Cell Degranulation , Cyclin-Dependent Kinase 5/metabolism , Eosinophils/enzymology , Cell Degranulation/drug effects , Cyclin-Dependent Kinase 5/antagonists & inhibitors , Cyclin-Dependent Kinase 5/genetics , Cyclin-Dependent Kinase 5/immunology , Dose-Response Relationship, Drug , Enzyme Activation , Eosinophil Peroxidase/metabolism , Eosinophils/drug effects , Eosinophils/immunology , HL-60 Cells , Humans , Immunologic Factors/pharmacology , Munc18 Proteins/metabolism , Nerve Tissue Proteins/metabolism , Phosphorylation , Protein Binding , Protein Kinase Inhibitors/pharmacology , RNA Interference , Signal Transduction , Time Factors , Transfection
17.
Mol Cell Biochem ; 360(1-2): 261-70, 2012 Jan.
Article in English | MEDLINE | ID: mdl-21948273

ABSTRACT

Airway remodelling in asthma involves various mediators modulating the production/breakdown of collagen by lung fibroblasts. Matrix metalloproteinase-1 (MMP-1) plays an important role in collagen breakdown. We recently showed that epithelial cell-derived extracellular form of 14-3-3σ is an important inducer of MMP-1 expression in skin fibroblasts. Thus, we hypothesized that 14-3-3 proteins are important regulators of MMP-1 expression in the respiratory airway. We examined the presence of extracellular 14-3-3 proteins in conditioned media obtained from primary lung epithelial cells, A549 and HS24 cells, and their effect on MMP-1 expression by lung fibroblasts (IMR-90). In addition, we evaluated IMR-90 response to 14-3-3 proteins in the presence of transforming growth factor-ß(1) (TGF-ß(1)), a cytokine known to decrease MMP-1 expression by fibroblasts. Extracellular 14-3-3α/ß, but not -σ, is released by the human-derived lung epithelial cell lines, A549 and HS24. Unlike dermal fibroblasts, IMR-90 cells do not produce MMP-1 in response to 14-3-3σ. Conversely, MMP-1 production was induced following treatment of IMR-90 with recombinant or lung epithelial cell-derived 14-3-3α/ß. These findings were also confirmed using primary human bronchial epithelial cells and lung fibroblasts obtained from non-asthmatic patients. The MMP-1-inducing effect of 14-3-3α/ß on IMR-90 was not inhibited by TGF-ß(1). Lung epithelial cell-derived 14-3-3α/ß has a potent MMP-1-inducing effect on airway fibroblasts. Modulation of MMP-1 by 14-3-3α/ß, may be important in the alteration of collagenase production associated with airway remodelling in obstructive lung diseases. Our data indicate that 14-3-3 proteins may be potential targets for future therapeutic strategies aimed at modulating tissue remodelling in asthma.


Subject(s)
14-3-3 Proteins/physiology , Epithelial Cells/metabolism , Gene Expression , Lung/pathology , Matrix Metalloproteinase 1/metabolism , 14-3-3 Proteins/metabolism , Airway Remodeling , Biomarkers, Tumor/metabolism , Cell Line, Tumor , Culture Media, Conditioned , Epithelial Cells/enzymology , Exonucleases/metabolism , Exoribonucleases , Fibroblasts/enzymology , Fibroblasts/metabolism , Gene Expression Regulation , Humans , Inflammation , L-Lactate Dehydrogenase/metabolism , Matrix Metalloproteinase 1/genetics , Primary Cell Culture , Protein Isoforms/metabolism , Transforming Growth Factor beta1/pharmacology , Transforming Growth Factor beta1/physiology
18.
Am J Pathol ; 175(5): 2043-52, 2009 Nov.
Article in English | MEDLINE | ID: mdl-19815714

ABSTRACT

Eosinophils expressing indoleamine 2, 3-dioxygenase (IDO) may contribute to T-helper cell (Th)2 predominance. To characterize human thymus IDO+ eosinophil ontogeny relative to Th2 regulatory gene expression, we processed surgically obtained thymi from 22 children (age: 7 days to 12 years) for immunohistochemistry and molecular analysis, and measured cytokine and kynurenine levels in tissue homogenates. Luna+ eosinophils ( approximately 2% of total thymic cells) decreased in number with age (P = 0.02) and were IDO+. Thymic IDO immunoreactivity (P = 0.01) and kynurenine concentration (P = 0.01) decreased with age as well. In addition, constitutively-expressed interleukin (IL)-5 and IL-13 in thymus supernatants was highest in youngest children. Eosinophil numbers correlated positively with expression of the Th2 cytokines IL-5, IL-13 (r = 0.44, P = 0.002), and IL-4 (r = 0.46, P = 0.005), transcription factor signal transducer and activator of transcription-6 (r = 0.68, P = 0.001), and the chemokine receptor, CCR3 (r = 0.17, P = 0.04), but negatively with IL-17 mRNA (r = -0.57, P = 0.02) and toll-like receptor 4 expression (r = -0.74, P = 0.002). Taken together, these results suggest that functional thymic IDO+ eosinophils during human infant life may have an immunomodulatory role in Th2 immune responses.


Subject(s)
Eosinophils/enzymology , Eosinophils/immunology , Immune System/growth & development , Indoleamine-Pyrrole 2,3,-Dioxygenase/immunology , Thymus Gland , Animals , Chemokines/genetics , Chemokines/immunology , Child , Child, Preschool , Cytokines/genetics , Cytokines/immunology , Eosinophils/cytology , Humans , Indoleamine-Pyrrole 2,3,-Dioxygenase/genetics , Infant , Infant, Newborn , Kynurenine/blood , Th2 Cells/immunology , Thymus Gland/cytology , Thymus Gland/enzymology , Thymus Gland/immunology , Toll-Like Receptors/genetics , Toll-Like Receptors/immunology
19.
Proc Natl Acad Sci U S A ; 105(47): 18478-83, 2008 Nov 25.
Article in English | MEDLINE | ID: mdl-19017810

ABSTRACT

Intracellular granules in several types of leukocytes contain preformed proteins whose secretions contribute to immune and inflammatory functions of leukocytes, including eosinophils, cells notably associated with asthma, allergic inflammation, and helminthic infections. Cytokines and chemokines typically elicit extracellular secretion of granule proteins by engaging receptors expressed externally on the plasma membranes of cells, including eosinophils. Eosinophil granules, in addition to being intracellular organelles, are found as intact membrane-bound structures extracellularly in tissue sites of eosinophil-associated diseases. Neither the secretory capacities of cell-free eosinophil granules nor the presence of functional cytokine and chemokine receptors on membranes of leukocyte granules have been recognized. Here, we show that granules of human eosinophils express membrane receptors for a cytokine, IFN-gamma, and G protein-coupled membrane receptors for a chemokine, eotaxin, and that these receptors function by activating signal-transducing pathways within granules to elicit secretion from within granules. Capacities of intracellular granule organelles to function autonomously outside of eosinophils as independent, ligand-responsive, secretion-competent structures constitute a novel postcytolytic mechanism for regulated secretion of eosinophil granule proteins that may contribute to eosinophil-mediated inflammation and immunomodulation.


Subject(s)
Cytoplasmic Granules/physiology , Eosinophils/ultrastructure , Organelles/physiology , Blotting, Western , Brefeldin A/pharmacology , Cytokines/metabolism , Eosinophils/drug effects , Flow Cytometry , Humans , Interferon-gamma/physiology , Microscopy, Electron, Transmission , Signal Transduction
20.
Biochem Biophys Res Commun ; 373(3): 382-6, 2008 Aug 29.
Article in English | MEDLINE | ID: mdl-18571497

ABSTRACT

Eosinophil degranulation is thought to play a pathophysiological role in asthma. Rab27A is a GTP-binding protein that is known to be essential for the degranulation of several leukocyte subsets and thus may be essential for eosinophil granule exocytosis. Here, we show that Rab27A mRNA and protein are expressed in human eosinophils. We have developed a novel assay to assess Rab27A activation and have found a similar activation pattern of this protein upon stimulation of eosinophils, neutrophils and NK cells suggesting a similar function in these cell types. Interestingly, Rab27A expression was elevated in eosinophils from asthmatic donors. Furthermore, eosinophils from eosinophilic donors displayed more rapid Rab27A activation kinetics than those from donors with lower eosinophil counts. Given that elevated blood eosinophil numbers correlate with increased priming of eosinophils, this pattern of Rab27A activation suggests differential protein expression in activated cells may allow eosinophils to degranulate more rapidly upon stimulation.


Subject(s)
Cell Degranulation , Eosinophilia/enzymology , Eosinophils/enzymology , rab GTP-Binding Proteins/biosynthesis , Asthma/enzymology , Bacterial Proteins/immunology , Enzyme Activation , Eosinophilia/blood , Eosinophils/immunology , Exocytosis , Humans , Killer Cells, Natural/enzymology , Killer Cells, Natural/immunology , Neutrophils/enzymology , Neutrophils/immunology , RNA, Messenger/biosynthesis , rab GTP-Binding Proteins/genetics , rab27 GTP-Binding Proteins
SELECTION OF CITATIONS
SEARCH DETAIL
...