ABSTRACT
With the acceleration of the aging society, neurodegenerative diseases, such as Alzheimer's disease (AD) and Parkinson's disease (PD), have become a rapidly growing global health crisis. Recent studies have indicated that microglia-neuron interactions are critical for maintaining homeostasis of the central nervous system. Genome-Wide Association Studies and brain imaging studies have suggested that microglia are activated in early stage of neurodegenerative diseases. Microglia are specialized phagocytes in the brain. The discovery of a new phagocytic pathway, trogocytosis, suggests that there is a close interaction between microglia and surviving neurons. In this review, we summarize the important roles of microglia in neurodegenerative diseases, and further analyze the functions and molecular mechanisms of microglia phagocytosis and trogocytosis.
Subject(s)
Alzheimer Disease , Genome-Wide Association Study , Humans , Microglia/metabolism , Neurodegenerative Diseases , Phagocytosis/physiologyABSTRACT
Abstract The Phagocytosis of fungal structures by neutrophils is a well-documented function of these immune cells. However, neutrophil phagocytosis of hyphal structures in the urine sediment is not usually observed during routine sample evaluation. This is a case of hyphal phagocytosis by neutrophils in the urine of a kidney allograft recipient patient.
Resumo A fagocitose de estruturas fúngicas por neutrófilos é uma função bem documentada destas células imunes. No entanto, a fagocitose de hifas por neutrófilos no sedimento urinário não é normalmente observada durante avaliação de rotina de amostras. Este é um caso de fagocitose de hifas por neutrófilos na urina de um paciente receptor de aloenxerto renal.
Subject(s)
Humans , Hyphae , Neutrophils , PhagocytosisABSTRACT
BACKGROUND: Opsonization, is the molecular mechanism by which target molecules promote interactions with phagocyte cell surface receptors to remove unwanted cells by induced phagocytosis. We designed an in vitro system to demonstrate that this procedure could be driven to eliminate adipocytes, using peptides mimicking regions of the complement protein C3b to promote opsonization and enhance phagocytosis. Two cell lines were used: (1) THP-1 monocytes differentiated to macrophages, expressing the C3b opsonin receptor CR1 in charge of the removal of unwanted coated complexes; (2) 3T3-L1 fibroblasts differentiated to adipocytes, expressing AQP7, to evaluate the potential of peptides to stimulate opsonization. (3) A co-culture of the two cell lines to demonstrate that phagocytosis could be driven to cell withdrawal with high efficiency and specificity. RESULTS: An array of peptides were designed and chemically synthesized p3691 and p3931 joined bound to the CR1 receptor activating phagocytosis (p < 0.033) while p3727 joined the AQP7 protein (p < 0.001) suggesting that opsonization of adipocytes could occur. In the co-culture system p3980 and p3981 increased lipid uptake to 91.2% and 89.0%, respectively, as an indicator of potential adipocyte phagocytosis. CONCLUSIONS: This in vitro model could help understand the receptorligand interaction in the withdrawal of unwanted macromolecules in vivo. The adipocyte-phagocytosis discussed may help to control obesity, since peptides of C3b stimulated the CR1 receptor, promoting opsonisation and phagocytosis of lipidcontaining structures, and recognition of AQP7 in the differentiated adipocytes, favored the phagocytic activity of macrophages, robustly supported by the co-culture strategy.
Subject(s)
Phagocytosis , Complement System Proteins , Adipocytes , In Vitro Techniques , Opsonin Proteins , Coculture Techniques , Foam Cells , Macrophages , Microscopy, FluorescenceABSTRACT
Dehydroepiandrosterone (DHEA) is a steroid hormone secreted by the adrenal glands, gonads and brain. It is a precursor to sex hormones and also is known to have immune modulatory activity. However, little is known about the relationship between DHEA and neutrophils and thus our study evaluates the influence of DHEA in the effector functions of neutrophils. Human neutrophils were treated in vitro with DHEA and further infected with Salmonella enterica serovar Typhimurium. The treatment of neutrophils with 0.01 µM of DHEA increased the phagocytosis of Salmonella independent of TLR4 as the treatment did not modulate the TLR4 expression. Additionally, DHEA caused a decrease in ROS (reactive oxygen species) production and did not influence the formation of the neutrophil extracellular trap (NET). Steroid treated neutrophils, infected or stimulated with LPS (lipopolysaccharide), showed reduced production of IL-8, compared to untreated cells. Also, the protein levels of p-NFκB were decreased in neutrophils treated with DHEA, and this reduction could explain the reduced levels of IL-8. These results led us to conclude that the steroid hormone DHEA has important modulatory functions in neutrophils
Subject(s)
Humans , Male , Adult , In Vitro Techniques , Dehydroepiandrosterone/analysis , Neutrophils/metabolism , Phagocytosis/genetics , Gonadal Steroid Hormones/pharmacology , Adrenal Glands/metabolism , Salmonella enterica/classificationABSTRACT
Abstract Objective Neutrophils are key effector cells of the innate immune system. They recognize antigens through membrane receptors, which are expressed during their maturation and activation. Neutrophils express FcγRII (CD32), FcγRIII (CD16), and FcγRI (CD64) after being activated by different factors such as cytokines and bacterial products. These receptors are involved with phagocytosis of IgG-opsonized microbes and enhance defense mechanisms. Based on that, our study seeks to compare the expression of FcγRII, FcγRIII, FcγRI, and CD11b on neutrophils from elderly and young subjects and their expression after in vitro activation with cytokines and LPS. Methodology Neutrophils were isolated from human peripheral blood and from mice bone marrow by density gradient. After isolation, FCγRs expression was immediately analyzed by flow cytometry or after in vitro stimulation. Results In freshly isolated cells, the percentage of FcγRIIIb+ and CD11b+ neutrophils were higher in samples from young individuals; FcγRIIIa expression was more prominent on aged neutrophils; FcγRIA expression was similar in all samples analyzed. Exposure to CXCL8 and LPS resulted in a higher percentage of FcγRIa+ neutrophils on elderly individuals' samples but lower when compared with neutrophils from young donors. We observed that LPS caused an increase in FcγRIIa expression on aging human neutrophils. In contrast, FcγRIIIb expression in response to CXCL8 and LPS stimulation was not altered in the four groups. CD11b expression was lower in neutrophils from elderly individuals even in response to LPS and CXCL8. In mice, we observed differences only regarding CD11b expression, which was increased on aged neutrophils. LPS exposure caused an increase in all FcγRs. Conclusions Our results suggest that, in humans, the overall pattern of FcγR expression and integrin CD11b are altered during aging and immunosenescence might contribute to age-related infection.
Subject(s)
Animals , Mice , Receptors, IgG , Neutrophils , Phagocytosis , Cell Count , Flow CytometryABSTRACT
Abstract INTRODUCTION This study aimed to determine the number of macrophages and apoptotic cells and perform annexin-A1 detection in patients with leishmaniasis. METHODS Patients with Leishmania infection were admitted to Júlio Müller University Hospital. RESULTS The number of apoptotic cells was higher in the exudative granulomatous reaction. The exudative cellular reaction displayed higher levels of annexin-A1 detection in macrophages and apoptotic cells. The correlation between annexin-A1 detection in apoptotic cells and macrophages was observed in exudative necrotic reaction and exudative necrotic-granulomatous reaction. CONCLUSIONS: Our data demonstrate the relevance of annexin-A1 in the regulation of apoptosis and phagocytosis in leishmaniasis.
Subject(s)
Humans , Leishmaniasis, Cutaneous , Annexin A1 , Phagocytosis , Apoptosis , MacrophagesABSTRACT
Painful procedures can affect the function of innate immune cells, such as neutrophils and macrophages, increasing the risk of infectious diseases. The present work aimed to verify if the analgesics flunixin meglumine or ketoprofen can attenuate the pain/discomfort of newborn lambs submitted by elastration tail docking and thereby avoid the impairment of blood granulocytes function. Twenty-one neonate lambs were divided into three treatments: the control group (n=7), not subjected to caudectomy; the flunixin group (n=7), subjected to caudectomy under local anesthesia and analgesia with two doses of flunixin meglumine; and the ketoprofen group (n=7), subjected to caudectomy under local anesthesia and two doses of ketoprofen. Pain indicators were observed by pain posture score (PS), the number of vocalizations (V), frequency of the movement of the ears (EF), and respiratory rates (RR), observed by a 10 minutes videos for each time points: -15min, 6h, 48h, and 144h. At the same time points, the reactive oxygen species (ROS) production and phagocytosis of blood granulocytes were measured by flow cytometry. At 6h after caudectomy, there was a pain indicator increase (RR, V, and PS), a blood granulocyte percentage increase, and a granulocytes phagocytosis reduction for both groups. At 48h, the ketoprofen group spend more time in pain posture and, at 144h, they exhibited a ROS production granulocyte reduction without signs of pain. We conclude the flunixin meglumine and ketoprofen did not prevent the acute pain/discomfort caused by caudectomy, because the groups showed a pain behavior and impaired of the innate immune response however, the flunixin meglumine was effective in controlling the chronic pain and their effects on blood granulocytes function in compare ketoprofen.(AU)
Procedimentos dolorosos podem afetar a função das células imunes inatas como neutrófilos e macrófagos, aumentando o risco de ocorrer doenças infeciosas. Desta maneira, o presente trabalho pretendeu verificar se os analgésicos flunixin meglumine ou cetoprofeno conseguem atenuar a dor/desconforto de cordeiros neonatos submetidos a caudectomia por elastração, evitando assim o comprometimento da função dos granulócitos sanguíneos. Para tanto 21 cordeiras foram aleatoriamente divididas em três tratamentos: grupo controle (n=7) não submetido a caudectomia, grupo flunixin (n=7) submetido a caudectomia precedida por anestesia local e duas doses de flunixin meglumine, e cetoprofeno (n=7) submetido a caudectomia precedida por anestesia local e duas doses de cetoprofeno. Mensurou-se os indicadores de dor/desconforto após caudectomia por observações de escore de postura de dor (EP), número de vocalizações (V), frequência de movimentar as orelhas (FO) e frequência respiratória (FR), observados em vídeos de 10 minutos nos momentos -15 min e 6, 48 e 144h. Nos mesmos momentos, avaliou-se a as funções de produção de espécies reativas de oxigênio (ERO) e de fagocitose por granulócitos sanguineos em citometria de fluxo. Notou-se aumento dos indicadores de dor (FR, de V e de EP), da porcentagem dos granulócitos sanguíneos e redução da eficiência de fagocitose em ambos os grupos as 6h. As 48h, os animais do grupo cetoprofeno ainda apresentava mais tempo em postura de dor que os demais grupos e as 144h, apresentou redução da produção ERO por granulócitos. Tais achados permitem concluir que tanto o flunexin meglumine como o cetoprofeno não preveniram dor/desconforto agudo promovido pela elastração, pois os dois grupos manifestaram comportamento de dor e redução da resposta imune inata. Ainda, o analgésico flunixin meglumine foi efetivo em controlar a dor mais tardia e seus efeitos na função de granulócitos sanguíneos em comparação ao cetoprofeno.(AU)
Subject(s)
Animals , Female , Phagocytosis , Sheep , Ketoprofen , Analgesia , Neutrophils , Reactive Oxygen SpeciesABSTRACT
Inflammation has accompanied humans since their first ancestors appeared on Earth. Aulus Cornelius Celsus (25 BC-50 AD), a Roman encyclopedist, offered a still valid statement about inflammation: "Notae vero inflammationis sunt quatuor: rubor et tumor cum calore and dolore", defining the four cardinal signs of inflammation as redness and swelling with heat and pain. While inflammation has long been considered as a morbid phenomenon, John Hunter (18th century) and Elie Metchnikoff (19th century) understood that it was a natural and beneficial event that aims to address a sterile or an infectious insult. Many other famous scientists and some forgotten ones have identified the different cellular and molecular players, and deciphered the different mechanisms of inflammation. This review pays tribute to some of the giants who made major contributions, from Hippocrates to the late 19th and first half of the 20th century. We particularly address the discoveries related to phagocytes, diapedesis, chemotactism, and fever. We also mention the findings of the various inflammatory mediators and the different approaches designed to treat inflammatory disorders.(AU)
Subject(s)
Phagocytosis , Transendothelial and Transepithelial Migration/physiology , Inflammation/classification , FeverABSTRACT
Hemocytes play an important role in the immune defense system of animals, especially for invertebrates that have no adaptive immune system. In those animals, hemocytes not only participate in the cellular immunity including phagocytosis, encapsulation, and nodules formation, but also the humoral immunity via storage and release of immune factors. Identification of the components of hemocytes is the basis for understanding the immune mechanism and the function of hemocytes. Despite various researches have been done on distinguishing the composition and function of shrimp hemocytes, no standard is used uniformly until now. So, we analyze and summarize the results on shrimp hemocytes research and offer a three subgroups category in this review. We also introduce the morphological characters and immune function of three subgroups in detail. We hope this work will be beneficial for understanding the function and molecular mechanism of hemocytes in invertebrate, bringing ideas for new separation technology development.
Subject(s)
Animals , Hemocytes , PhagocytosisABSTRACT
This study aimed to evaluate the neutrophil oxidative metabolism and phagocytosis of Zymonsan particles of primiparous and pluriparous Lacaune ewes during the first 30 days after lambing. A total of 20 ewes were evaluated, 10 primiparous (GPR) and 10 pluriparous (GPL). Evaluation of basal oxidative metabolism was performed using the nitroblue tetrazolium (NBT) technique, stimulating neutrophil phagocytosis with Zymosan particles. Blood samples were collected at parturition day (M1) and 1, 3, 7, 15 and 30 days after parturition, corresponding to M2, M3, M4, M5 and M6, respectively. In relation to the groups, GPR presented lower oxidative basal metabolism neutrophils in M1 compared to M4, in M3 with M1, M2, M4 and M5. In M4 and M5 differences were found at all times and in M6 with M4 and M5. Higher percentage of neutrophils than phagocytes were found in M4, M5 and M6 than in M1 and M2 in GPL animals. At all times GPR presented a lower percentage of phagocytosis than GPL. Thus it is concluded that the immune response in pluriparous sheep was more efficient than in primiparous sheep.(AU)
Subject(s)
Animals , Female , Phagocytosis , Sheep/blood , Metabolism , Neutrophils/physiology , Postpartum Period/bloodABSTRACT
Abstract Although the potential of surrogate propagation technology for aquaculture and conservation of Neotropical fish, the poor understanding of the host immune system may results in rejection and destruction of the donor material. Thus, it is necessary to study and to develop methods to evaluate the effects of immunosuppressive drugs employment and to evaluate the immunocompatibility between donor and receptor. Thus, the present study aimed to optimize a methodology to assess in vivo phagocytosis in Astyanax altiparanae using Saccharomyces cerevisiae and to evaluate their hematological response resultant from the inflammatory induction. To this, S. cerevisiae were labeled with Congo red and injected in the coelomic cavity of A. altiparanae at the concentration of 2.5 x 106 cells mL-1. A PBS solution and a non-injected group were kept as control. Fish blood was sampled and the phagocytic capacity and index were determined at 1, 2, 3 and 6 h post-injection (hpi). The yeast injection successfully stimulated phagocytosis, with the best result for phagocytosis assessment after 2 hpi. Moreover, it was achieved a high traceability of phagocytized and non-phagocytized yeast under optic microscopy analysis due to the Congo red labeling. The hematological profile was similar to usually observed in early infections, indicating lymphocyte migration to inflammatory site and increase in number of circulating phagocytes due to natural response to inflammatory stimulus. In conclusion, our method was efficient to assess in vivo phagocytosis in A. altiparanae and will be an important tool to evaluate the efficacy of immunosuppressive drugs in this species. Additionally, these results may serve as support for further studies in fish immunocompetence, both in laboratory and in field conditions.
Resumo Apesar do potencial apresentado pela tecnologia de propagação mediada para a aquicultura e conservação de peixes Neotropicais, o pobre entendimento do sistema imune do hospedeiro pode resultar na rejeição e destruição do material do doador. Com isso, se fazem necessários o estudo e o desenvolvimento de métodos para análise tanto dos efeitos de drogas imunossupressoras quanto para a avaliação da imunocompatibilidade entre doadores e receptores. Logo, o presente estudo teve como objetivo aperfeiçoar um método para analisar a fagocitose in vivo em Astyanax altiparanae usando Saccharomyces cerevisiae marcado e avaliar seu perfil hematológico resultante da indução inflamatória. Para isso, S. cerevisiae foram marcados com vermelho Congo e injetados na cavidade celomática dos A. altiparanae na concentração de 2,5 x 106 células.mL-1. Peixes injetados com PBS e peixes não injetados foram mantidos como controle. Sangue foi colhido e a capacidade fagocítica e o índice fagocítico foram determinados após 1, 2, 3 e 6 horas após à injeção (hpi). A injeção de levedura estimulou a fagocitose com sucesso, com o melhor resultado atingido após 2 hpi. Ainda, foi observada uma alta rastreabilidade das leveduras fagocitadas e não fagocitadas sob microscopia óptica devido à marcação com vermelho Congo. O perfil hematológico foi similar ao observado usualmente em infecções recém-induzidas, indicando migração de linfócitos ao sítio inflamatório e aumento no número de fagócitos circulantes devido à resposta natural ao estímulo inflamatório. Como conclusão, nosso método foi eficiente para analisar a fagocitose in vivo em A. altiparanae e será uma ferramenta importante para a avaliação de eficácia de drogas imunossopressoras para esta espécie. Em adição, estes resultados podem contribuir para futuros estudos em imunocompetência em peixes, tanto em âmbito laboratorial quanto a campo.
Subject(s)
Animals , Characidae , Hematology , Phagocytosis , Saccharomyces cerevisiae , AquacultureABSTRACT
Resumen La linfohistiocitosis hemofagocítica (LHH) por Histoplasma capsulatum, presentación rara de la histoplasmosis diseminada, es causada por la fagocitosis de las células hematopoyéticas por macrófagos tisulares. Presentamos el caso de un paciente masculino de 44 años con trasplante renal que asiste por fiebre sin otra sintomatología. Inicialmente se obtiene una gota gruesa positiva para P. vivax, iniciando manejo antimalárico. A los 2 días de tratamiento, el paciente presenta disfunción multiórganica, se rectifica diagnóstico en centro de referencia reportando en extendido de sangre periférica la presencia de levaduras de H. capsulatum en polimorfonucleares, resultado confirmado con prueba de inmunodifusión. Se ajusta manejo, pero el paciente fallece. El diagnóstico de infecciones por gérmenes inusuales con presentaciones inespecíficas es un reto en pacientes con inmunosupresión.
Abstract Hemophagocytic Lymphohistiocytosis (HLH) induced by Histoplasma capsulatum is a rare entity who is characterized by phagocytosis of hematopoietic cells by tissue macrophages. A 44-year-old male patient with kidney transplantation was admitted to our ambulatory service with fever. Initially, we performed a thick drop test who was positive for P. vivax, so antimalarial therapy was initiated. Patient then progressed to multiple organ dysfunction after 2 days of treatment. Thus, a reference center went back over the blood smear which revealed the presence of yeast cells H. capsulatum within polymorphonuclear cells. This result was confirmed by an immunodifussion assay. Despite of antifungal treatment, patient passed away. The diagnosis for unusual microorganism with unspecific clinical presentation could be a challenge in immunosupressive patients.
Subject(s)
Humans , Male , Adult , Lymphohistiocytosis, Hemophagocytic , Phagocytosis , Hematopoietic Stem Cells , Kidney Transplantation , HistoplasmaABSTRACT
Criptococose é uma doença grave que afeta tanto imunocomprometidos quanto imunocompetentes, com isso analisar a virulência é fundamental para novas terapêuticas. Objetivo: Analisar a capacidade de virulência e susceptibilidade aos antifúngicos de Cryptococcus spp. isolados de líquor de pacientes de hospital do norte do Paraná. Métodos: A partir de dois isolados clínicos C. neoformans e C. gattii, realizou-se a confirmação da identificação. Para a virulência, avaliou-se o tamanho da cápsula, capacidade de sobrevivência após exposição a neutrófilos, produção de melanina e urease. No antifungigrama por difusão em disco utilizou-se: anfotericina B, cetoconazol, voriconazol, itraconazol e miconazol. Resultados: C. gattii destaca-se por maior desenvolvimento da cápsula além da melhor capacidade de sobreviver a fagocitose em relação ao C. neoformans. No antifungigrama, ambos os isolados se apresentam sensíveis às drogas estudadas. Conclusão: Esses achados contribuem para a compreensão das diferentes patogêneses entre C. gattii e C. neoformans.
Cryptococcosis is a serious disease that can affect both immunocompromised and immunocompetent individuals, thus the virulence analysis is fundamental for the development of new treatments. Objective: To analyze the virulence and susceptibility of Cryptococcus spp. isolated from cerebrospinal fluid of patients from a hospital in the north of Paraná. Methods: From two clinical isolates, C. neoformans and C. gattii were confirmed and identified. For virulence, capsule size, survival capacity after exposure to neutrophils, melanin production and urease were evaluated. In the disc-diffusion method, the following antifungals were used: amphotericin B, ketoconazole, voriconazole, itraconazole and miconazole Results: It was observed that C. gattii presents greater results for development of the capsule beside presenting the best ability to survive phagocytosis in relation to C. neoformans. In the disc-diffusion method, both isolates presented sensitivity to the studied drugs. Conclusion: These findings contribute to the understanding of the different pathogens between C. gattii and C. neoformans.
Subject(s)
Cryptococcosis/virology , Virulence Factors/analysis , Antifungal Agents/analysis , Phagocytosis , Urease/urine , Yeasts/virology , Capsules/analysis , Pharmaceutical Preparations , Amphotericin B/analysis , Itraconazole , Cryptococcus neoformans/virology , Agar/analysis , Cryptococcus gattii/virology , Voriconazole , Melanins/analysis , Miconazole , Neutrophils/virologyABSTRACT
BACKGROUND The mechanism of resistance to SbIII in Leishmania is complex, multifactorial and involves not only biochemical mechanisms, but also other elements, such as the immune system of the host. OBJECTIVES In this study, putative changes in the immunological profile of human monocytes infected with wild-type (WT) and antimony (SbIII)-resistant Leishmania (Viannia) braziliensis and Leishmania (Leishmania) infantum lines were evaluated. METHODS Susceptibility assays WT and SbIII-resistant L. braziliensis and L. infantum were performed using lines THP-1 human monocytic lineage. Phagocytic capacity, cytokine profile, intracellular nitric oxide (NO) production and surface carbohydrate residues profile were performed in peripheral blood monocytes by flow cytometry. FINDINGS The phagocytic capacity and intracellular NO production by classical (CD14++CD16-) and proinflammatory (CD14++CD16+) monocytes were higher in the presence of L. infantum lines compared to L. braziliensis lines. The results also highlight proinflammatory monocytes as the cellular subpopulation of major relevance in a phagocytosis event and NO expression. It is important to note that L. infantum induced a proinflammatory cytokine profile characterised by higher levels of TNF-α in culture supernatant than L. braziliensis. Conversely, both Leishmania lines induce high levels of IL-6 in culture supernatant. Analysis of the expression profile of surface carbohydrates showed that L. braziliensis presents 4.3-fold higher expression of galactose(β1,4)N-acetylglucosamine than L. infantum line. Interestingly, the expression level of α-N-acetylgalactosamine residues was 2-fold lower in the SbIII-resistant L. braziliensis line than its counterpart WT line, indicating differences in surface glycoconjugates between these lines. MAIN CONCLUSIONS Our results showed that L. braziliensis and L. infantum induce different innate immune responses and a highly inflammatory profile, which is characteristic of infection by L. infantum, the species associated with visceral disease.
Subject(s)
Humans , Male , Female , Adult , Young Adult , Phagocytosis/immunology , Leishmania braziliensis/immunology , Monocytes/parasitology , Leishmania infantum/immunology , Antimony/pharmacology , Nitric Oxide/biosynthesis , Antiprotozoal Agents/pharmacology , Leishmania braziliensis/drug effects , Drug Resistance , Monocytes/immunology , Leishmania infantum/drug effects , Flow Cytometry , Immunity, InnateABSTRACT
The objective of this study was to investigate the relationship between PI3K/mTOR/RhoA signaling regulated cytoskeletal rearrangements and phagocytic capacity of macrophages. RAW264.7 macrophages were divided into four groups; blank control, negative control, PI3K-RNAi, and mTOR-RNAi. The cytoskeletal changes in the macrophages were observed. Furthermore, the phagocytic capacity of macrophages against Escherichia coli is reported as mean fluorescence intensity (MFI) and percent phagocytosis. Transfection yielded 82.1 and 81.5% gene-silencing efficiencies against PI3K and mTOR, respectively. The PI3K-RNAi group had lower mRNA and protein expression levels of PI3K, mTOR, and RhoA than the blank and negative control groups (Р<0.01). The mTOR-RNAi group had lower mRNA and protein levels of mTOR and RhoA than the blank and the negative control groups (Р<0.01). Macrophages in the PI3K-RNAi group exhibited stiff and inflexible morphology with short, disorganized filopodia and reduced number of stress fibers. Macrophages in the mTOR-RNAi group displayed pronounced cellular deformations with long, dense filopodia and an increased number of stress fibers. The PI3K-RNAi group exhibited lower MFI and percent phagocytosis than blank and negative control groups, whereas the mTOR-RNAi group displayed higher MFI and percent phagocytosis than the blank and negative controls (Р<0.01). Before and after transfection, the mRNA and protein levels of PI3K were both positively correlated with mTOR and RhoA (Р<0.05), but the mRNA and protein levels of mTOR were negatively correlated with those of RhoA (Р<0.05). Changes in the phagocytic capacity of macrophages were associated with cytoskeletal rearrangements and were regulated by the PI3K/mTOR/RhoA signaling pathway.
Subject(s)
Humans , Animals , Rats , Phagocytosis/physiology , Cytoskeleton/metabolism , Phosphatidylinositol 3-Kinases/metabolism , rhoA GTP-Binding Protein/metabolism , TOR Serine-Threonine Kinases/metabolism , Macrophages/metabolism , Transfection , Signal Transduction , Blotting, Western , Gene Silencing , RNA Interference , Real-Time Polymerase Chain Reaction , RAW 264.7 Cells , Genetic VectorsABSTRACT
Scavenger receptors typically bind to multiple ligands on a cell surface, including endogenous and modified host-derived molecules and microbial pathogens. They promote the elimination of degraded or harmful substances such as non-self or altered-self targets through endocytosis, phagocytosis, and adhesion. Currently, scavenger receptors are subdivided into eight classes based on several variations in their sequences due to alternative splicing. Since recent studies indicate targeting scavenger receptors has been involved in cancer prognosis and carcinogenesis, we will focus on the current knowledge about the emerging role of scavenger receptor classes A to E in cancer progression.
Subject(s)
Alternative Splicing , Carcinogenesis , Endocytosis , Ligands , Macrophages , Phagocytosis , Prognosis , Receptors, ScavengerABSTRACT
The macrophage displays functional and phenotypic diversity, which appears, in no small part, to stem from the ability of macrophages to adapt functionally to changes in their tissue microenvironment. Here, we describe the differential activity of peritoneal macrophages with or without the presence of thioglycollate (TG), an inflammatory drug that encouraged the recruitment of macrophages, during aging. The peritoneal-resident macrophages dramatically reduced in phagocytosis and pro-inflammatory cytokines secretion with aging, whereas the functions of macrophages recruited by TG were not significantly changed with aging. These results suggest that macrophages may be changed by their environment in advanced age, and could provide possible explanations for the controversial results regarding differential changes in macrophages in other papers.
Subject(s)
Aging , Cytokines , Inflammation , Macrophages , Macrophages, Peritoneal , PhagocytosisABSTRACT
The purpose of this study is to provide a culture for mouse bone marrow-derived macrophages (BMDM) and peritoneal macrophages (PM) and to characterize their molecular and cellular biology. The cell number and purity from the primary culture were assessed by cell counter and flow cytometry, respectively. Morphological features were evaluated by inverted microscope. Phagocytosis by macrophages was detected by the neutral red dye uptake assay. Phenotypic markers were analyzed by real-time fluorescent quantitative PCR. Our results show that the cell number was much higher from culture of BMDM than PM, while there was no significant difference regarding the percentage of F4/80+CD11b+ cells (98.30%±0.53% vs. 94.83%±1.42%; P>0.05). The proliferation rate of BMDM was significantly higher than PM in the presence of L929 cell conditioned medium, by using CCK-8 assay. However, PM appeared to adhere to the flask wall and extend earlier than BMDM. The phagocytosis capability of un-stimulated BMDM was significantly higher than PM, as well as lipopolysaccharide (LPS)-stimulated BMDM, except the BMDM stimulated by low dose LPS (0.1 μg/mL). Furthermore, Tnfα expression was significantly higher in un-stimulated BMDM than PM, while Arg1 and Ym1 mRNA expression were significantly lower than PM. The expression difference was persistent if stimulated by LPS+IFN-γ or IL-4. Our data indicate that bone marrow can get larger amounts of macrophages than peritoneal cavity. However, it should be aware that the molecular and cellular characteristics were different between these two culture systems.
Subject(s)
Animals , Bone Marrow Cells , Physiology , Cells, Cultured , Culture Media, Conditioned , Lipopolysaccharides , Metabolism , Macrophages , Classification , Physiology , Mice , PhagocytosisABSTRACT
Alveolar macrophages (AMs) are an essential part of defense mechanisms within the lungs and their phagocytic activity is important for organ homeostasis. The phagocytic ability of AMs obtained from bronchoalveolar lavage from 17 mature mixed-breed pleasure horses (8 healthy and 9 diagnosed with mild equine asthma) was studied through assays with Leishmania (Viannia) braziliensis promastigotes, which enabled the calculation of a phagocytic index (PI) and a survival index (SI). Results indicate that phagocytic activity of AMs in asthma affected horses is similar to healthy horses, while leishmanicidal activity is significantly increased in horses with asthma.(AU)
Os macrófagos alveolares (MAs) são uma parte essencial dos mecanismos de defesa dentro dos pulmões e sua atividade fagocítica é importante para a homeostase desse órgão. A capacidade fagocitária dos MAs obtidos do lavado broncoalveolar de 17 equinos adultos, sem raça definida (oito saudáveis e nove com diagnóstico de asma equina leve), foi estudada por meio de ensaios com promastigotas de Leishmania (Viannia) braziliensis. Foi calculado o índice fagocítico e o índice de sobrevivência. Os resultados indicam que a atividade fagocítica de MAs em cavalos com asma é semelhante a cavalos saudáveis, enquanto a atividade leishmanicida está significativamente aumentada em cavalos com essa enfermidade.(AU)
Subject(s)
Animals , Asthma/veterinary , Leishmania braziliensis , Macrophages, Alveolar/parasitology , Horses/parasitology , PhagocytosisABSTRACT
Somando a maioria dos leucócitos presentes na corrente sanguínea, os neutrófilos são células polimorfonucleares e especializadas no combate a infecções através da fagocitose do patógeno e liberação de seus conteúdos granulares. Também são capazes de liberar armadilhas extracelulares (neutrophil extracellular traps, NETs), que são estruturas constituídas de componentes intracelulares, como fibras de cromatina e proteínas derivadas de grânulos citoplasmáticos. As NETs são liberadas em resposta a vários estímulos, como de microrganismos, citocinas e complexos antígeno-anticorpo, e possuem o papel de capturar microrganismos e até mesmo matá-los. Porém, quando essas estruturas não são completamente eliminadas pelo organismo, elas podem gerar danos à saúde, pois podem ser produzidos anticorpos contra as estruturas que as compõem. Neste artigo, é feita uma revisão dos acontecimentos que levam à liberação de NETs pelos neutrófilos, a importância disso para a saúde e o envolvimento dessas estruturas em processos de autoimunidade, utilizando artigos publicados desde a descoberta das NETs, que ocorreu em 2004.
Accounting for most leukocytes present in the bloodstream, neutrophils are polymorphonuclear cells that specialize in dealing with microorganisms through phagocytosis and release of granule contents. They are also able to release extracellular traps (NETs), which are structures consisting of intracellular components such as chromatin fibers and proteins derived from cytoplasmic granules. NETs are released in response to various stimuli, such as to microorganisms, cytokines and immune complexes, and their role is to capture microorganisms and kill them. However, when these structures are not properly eliminated by the body, they may generate health damage because antibodies can be produced against them. This article provides a review of the events triggering the release of NETs, their importance for health and the involvement of these structures in autoimmune processes, using articles published since the discovery of NETs in 2004.