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1.
Fish Shellfish Immunol ; 114: 161-170, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33957267

RESUMO

The family of fibrinogen-related proteins (FREPs) is a group of proteins with fibrinogen-like (FBG) domains, which play important roles as pattern recognition receptors (PRRs) in the innate immune responses. In the present study, a fibrinogen-like protein was identified from the oyster Crassostrea gigas (defined as CgFREP1). The open reading frame of CgFREP1 was of 966 bp that encoded a predicted polypeptide of 321 amino acids comprising a signal peptide and a fibrinogen-like domain. The mRNA expression of CgFREP1 was detected in all the examined tissues. The recombinant CgFREP1 (rCgFREP1) displayed binding activities to lipopolysaccharide (LPS), mannose (MAN), as well as Gram-positive bacteria (Micrococcus luteus and Staphylococcus aureus) and Gram-negative bacteria (Vibrio splendidus and Escherichia coli). The rCgFREP1 displayed the agglutinating activity towards M. luteus, V. splendidus and E. coli in the presence of Ca2+. rCgFREP1 was able to enhance the phagocytic activity of haemocytes towards V. splendidus, and exhibited binding activity to the CUB domain of CgMASPL-1. These results suggest that CgFREP1 not only serves as a PRR to recognize and agglutinate different bacteria but also mediates the haemocytes phagocytosis towards V. splendidus.


Assuntos
Crassostrea/microbiologia , Hemócitos/fisiologia , Fagocitose/fisiologia , Proteínas/metabolismo , Vibrio/fisiologia , Animais , Crassostrea/imunologia , Crassostrea/metabolismo , Interações Hospedeiro-Patógeno , Micrococcus luteus/fisiologia , Proteínas/imunologia , Staphylococcus aureus/fisiologia
2.
Fish Shellfish Immunol ; 114: 229-237, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33979692

RESUMO

The freshwater aquifers of the Indo-Gangetic plains support rich biodiversity which is under the threat of arsenic contamination. The filter feeding bivalve mollusc Lamellidens marginalis is a sessile and sentinel resident of these freshwater habitats. In the present study, the classical cell behaviours of adhesion and aggregation were monitored in the circulating haemocytes of the freshwater bivalve under the exposure of sodium arsenite (NaAsO2) at sublethal concentrations in controlled laboratory conditions for a maximum time-span of sixteen days. The toxic metalloid significantly inhibited non-self adhesion, inter-haemocyte interactions and haemocyte aggregation in a dose and time dependent manner. The natural occurrence of the filopods on the haemocytes was significantly diminished in the bivalves exposed to the inorganic arsenite. Moreover, a significant fall in the kinetics of phagocytosis index and haemocyte adhesion was observed under the in vitro exposure to NaAsO2. Compromised non-self adhesion, cell-cell aggregation and phagocytosis of non-self particles by the bivalve haemocytes probably indicate susceptible immunological status of the bivalve. Such vulnerable immunity of the bivalve probably signifies the nature of imminent threat to the freshwater ecosystem as a whole under inorganic arsenite exposure. The findings would be helpful to design bivalve haemocyte based inexpensive biomonitoring tool to assess the health of freshwater ecosystem under potential arsenic threat.


Assuntos
Arsênio/toxicidade , Bivalves/citologia , Adesão Celular/fisiologia , Agregação Celular/fisiologia , Hemócitos/fisiologia , Fagocitose/fisiologia , Animais , Arseniatos/toxicidade , Poluentes Químicos da Água/toxicidade
3.
Nat Commun ; 12(1): 3015, 2021 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-34021136

RESUMO

The role of microglia cells in Alzheimer's disease (AD) is well recognized, however their molecular and functional diversity remain unclear. Here, we isolated amyloid plaque-containing (using labelling with methoxy-XO4, XO4+) and non-containing (XO4-) microglia from an AD mouse model. Transcriptomics analysis identified different transcriptional trajectories in ageing and AD mice. XO4+ microglial transcriptomes demonstrated dysregulated expression of genes associated with late onset AD. We further showed that the transcriptional program associated with XO4+ microglia from mice is present in a subset of human microglia isolated from brains of individuals with AD. XO4- microglia displayed transcriptional signatures associated with accelerated ageing and contained more intracellular post-synaptic material than XO4+ microglia, despite reduced active synaptosome phagocytosis. We identified HIF1α as potentially regulating synaptosome phagocytosis in vitro using primary human microglia, and BV2 mouse microglial cells. Together, these findings provide insight into molecular mechanisms underpinning the functional diversity of microglia in AD.


Assuntos
Doença de Alzheimer/metabolismo , Microglia/metabolismo , Fagocitose/fisiologia , Placa Amiloide/metabolismo , Idoso , Idoso de 80 Anos ou mais , Animais , Encéfalo/metabolismo , Modelos Animais de Doenças , Feminino , Expressão Gênica , Redes Reguladoras de Genes , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Masculino , Camundongos , Pessoa de Meia-Idade , Placa Amiloide/genética , Transcriptoma
4.
Nat Commun ; 12(1): 2863, 2021 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-34001904

RESUMO

During injury, monocytes are recruited from the circulation to inflamed tissues and differentiate locally into mature macrophages, with prior reports showing that cavity macrophages of the peritoneum and pericardium invade deeply into the respective organs to promote repair. Here we report a dual recombinase-mediated genetic system designed to trace cavity macrophages in vivo by intersectional detection of two characteristic markers. Lineage tracing with this method shows accumulation of cavity macrophages during lung and liver injury on the surface of visceral organs without penetration into the parenchyma. Additional data suggest that these peritoneal or pleural cavity macrophages do not contribute to tissue repair and regeneration. Our in vivo genetic targeting approach thus provides a reliable method to identify and characterize cavity macrophages during their development and in tissue repair and regeneration, and distinguishes these cells from other lineages.


Assuntos
Fígado/fisiopatologia , Lesão Pulmonar/fisiopatologia , Macrófagos/fisiologia , Monócitos/fisiologia , Cavidade Peritoneal/fisiologia , Cavidade Pleural/fisiologia , Animais , Linhagem da Célula/genética , Células Cultivadas , Fígado/lesões , Ativação de Macrófagos/fisiologia , Macrófagos/citologia , Macrófagos/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Microscopia de Fluorescência/métodos , Monócitos/citologia , Monócitos/metabolismo , Cavidade Peritoneal/citologia , Fagocitose/fisiologia , Cavidade Pleural/citologia
5.
Int J Mol Sci ; 22(7)2021 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-33808261

RESUMO

In host-parasitoid interactions, antagonistic relationship drives parasitoids to vary in virulence in facing different hosts, which makes these systems excellent models for stress-induced evolutionary studies. Venom compositions varied between two strains of Tetrastichus brontispae, Tb-Bl and Tb-On. Tb-Bl targets Brontispa longissima pupae as hosts, and Tb-On is a sub-population of Tb-Bl, which has been experimentally adapted to a new host, Octodonta nipae. Aiming to examine variation in parasitoid virulence of the two strains toward two hosts, we used reciprocal injection experiments to compare effect of venom/ovarian fluids from the two strains on cytotoxicity, inhibition of immunity and fat body lysis of the two hosts. We found that Tb-Onvenom was more virulent towards plasmatocyte spreading, granulocyte function and phenoloxidase activity than Tb-Blvenom. Tb-Blovary was able to suppress encapsulation and phagocytosis in both hosts; however, Tb-Onovary inhibition targeted only B. longissima. Our data suggest that the venom undergoes rapid evolution when facing different hosts, and that the wasp has good evolutionary plasticity.


Assuntos
Besouros/parasitologia , Especificidade de Hospedeiro/genética , Interações Hospedeiro-Parasita/fisiologia , Animais , Evolução Molecular , Himenópteros/fisiologia , Fagocitose/fisiologia , Pupa/parasitologia , Virulência , Vespas/fisiologia
6.
Int J Mol Sci ; 22(9)2021 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-33925691

RESUMO

Several studies, including genome wide association studies (GWAS), have strongly suggested a central role for the ATP-binding cassette transporter subfamily A member 7 (ABCA7) in Alzheimer's disease (AD). This ABC transporter is now considered as an important genetic determinant for late onset Alzheimer disease (LOAD) by regulating several molecular processes such as cholesterol metabolism and amyloid processing and clearance. In this review we shed light on these new functions and their cross-talk, explaining its implication in brain functioning, and therefore in AD onset and development.


Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Transportadores de Cassetes de Ligação de ATP/genética , Amiloide/metabolismo , Peptídeos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Encéfalo/metabolismo , Colesterol/metabolismo , Predisposição Genética para Doença/genética , Estudo de Associação Genômica Ampla , Humanos , Fagocitose/fisiologia , Polimorfismo de Nucleotídeo Único/genética
7.
Int J Mol Sci ; 22(4)2021 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-33672129

RESUMO

Neuroinflammation, typically manifest as microglial activation and astrogliosis accompanied by transcriptomic alterations, represents a common hallmark of various neurodegenerative conditions including prion diseases. Microglia play an overall neuroprotective role in prion disease, whereas reactive astrocytes with aberrant phenotypes propagate prions and contribute to prion-induced neurodegeneration. The existence of heterogeneous subpopulations and dual functions of microglia and astrocytes in prion disease make them potential targets for therapeutic intervention. A variety of neuroinflammation-related molecules are involved in prion pathogenesis. Therapeutics targeting neuroinflammation represents a novel approach to combat prion disease. Deciphering neuroinflammation in prion disease will deepen our understanding of pathogenesis of other neurodegenerative disorders.


Assuntos
Inflamação/patologia , Microglia/patologia , Doenças Priônicas/fisiopatologia , Animais , Encéfalo/metabolismo , Encéfalo/patologia , Quimiocinas/metabolismo , Citocinas/metabolismo , Gliose/etiologia , Humanos , Microglia/metabolismo , Fagocitose/fisiologia , Doenças Priônicas/metabolismo , Receptores Toll-Like/metabolismo
8.
Nat Commun ; 12(1): 1508, 2021 03 08.
Artigo em Inglês | MEDLINE | ID: mdl-33686057

RESUMO

LC3-associated phagocytosis (LAP) contributes to a wide range of cellular processes and notably to immunity. The stabilization of phagosomes by the macroautophagy machinery in human macrophages can maintain antigen presentation on MHC class II molecules. However, the molecular mechanisms involved in the formation and maturation of the resulting LAPosomes are not completely understood. Here, we show that reactive oxygen species (ROS) produced by NADPH oxidase 2 (NOX2) stabilize LAPosomes by inhibiting LC3 deconjugation from the LAPosome cytosolic surface. NOX2 residing in the LAPosome membrane generates ROS to cause oxidative inactivation of the protease ATG4B, which otherwise releases LC3B from LAPosomes. An oxidation-insensitive ATG4B mutant compromises LAP and thereby impedes sustained MHC class II presentation of exogenous Candida albicans antigens. Redox regulation of ATG4B is thereby an important mechanism for maintaining LC3 decoration of LAPosomes to support antigen processing for MHC class II presentation.


Assuntos
Apresentação do Antígeno/fisiologia , Autofagia/fisiologia , Antígenos de Histocompatibilidade Classe II/metabolismo , Fagossomos/metabolismo , Proteínas Adaptadoras de Transporte Vesicular/metabolismo , Antígenos de Fungos , Proteínas Relacionadas à Autofagia , Candida albicans , Classe III de Fosfatidilinositol 3-Quinases , Cisteína Endopeptidases/metabolismo , Células HEK293 , Humanos , Macroautofagia , Macrófagos/metabolismo , NADPH Oxidase 2/metabolismo , Oxirredução , Fagocitose/fisiologia , Espécies Reativas de Oxigênio/metabolismo
9.
Nat Commun ; 12(1): 1158, 2021 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-33627648

RESUMO

Niemann-Pick type C disease is a rare neurodegenerative disorder mainly caused by mutations in NPC1, resulting in abnormal late endosomal/lysosomal lipid storage. Although microgliosis is a prominent pathological feature, direct consequences of NPC1 loss on microglial function remain not fully characterized. We discovered pathological proteomic signatures and phenotypes in NPC1-deficient murine models and demonstrate a cell autonomous function of NPC1 in microglia. Loss of NPC1 triggers enhanced phagocytic uptake and impaired myelin turnover in microglia that precede neuronal death. Npc1-/- microglia feature a striking accumulation of multivesicular bodies and impaired trafficking of lipids to lysosomes while lysosomal degradation function remains preserved. Molecular and functional defects were also detected in blood-derived macrophages of NPC patients that provide a potential tool for monitoring disease. Our study underscores an essential cell autonomous role for NPC1 in immune cells and implies microglial therapeutic potential.


Assuntos
Colesterol/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Microglia/metabolismo , Doença de Niemann-Pick Tipo C/metabolismo , Animais , Western Blotting , Células Cultivadas , Feminino , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Masculino , Espectrometria de Massas , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Bainha de Mielina/metabolismo , Doença de Niemann-Pick Tipo C/genética , Fagocitose/genética , Fagocitose/fisiologia , Proteômica/métodos
10.
Methods Mol Biol ; 2241: 113-132, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33486732

RESUMO

Eosinophil apoptosis (programmed cell death) plays an important role in several inflammatory and allergic conditions. Apoptosis triggers various mechanisms including activation of cysteine-aspartic proteases (caspases) and is characterized by morphological and biochemical changes. These include cellular condensation, nuclear fragmentation, increased mitochondrial permeability with loss of membrane potential, and exposure of phosphatidylserine on the cell membrane. A greater understanding of apoptotic mechanisms, subsequent phagocytosis (efferocytosis), and regulation of these processes is critical to understanding disease pathogenesis and development of potential novel therapeutic agents. Release of soluble factors and alterations to surface marker expression by eosinophils undergoing apoptosis aid them in signaling their presence to the immediate environment, and their subsequent recognition by phagocytic cells such as macrophages. Uptake of apoptotic cells usually suppresses inflammation by restricting proinflammatory responses and promoting anti-inflammatory and tissue repair responses. This, in turn, promotes resolution of inflammation. Defects in the apoptotic or efferocytosis mechanisms perpetuate inflammation, resulting in chronic inflammation and enhanced disease severity. This can be due to increased eosinophil life span or cell necrosis characterized by loss of cell membrane integrity and release of toxic intracellular mediators. In this chapter, we detail some of the key assays that are used to assess eosinophil apoptosis, as well as the intracellular signaling pathways involved and phagocytic clearance of these cells.


Assuntos
Apoptose/fisiologia , Eosinófilos/citologia , Imuno-Histoquímica/métodos , Fagocitose/fisiologia , Anexina A5/química , Apoptose/imunologia , Transporte Biológico , Caspases/metabolismo , Eosinófilos/fisiologia , Humanos , Inflamação/metabolismo , Macrófagos/metabolismo , Potenciais da Membrana/fisiologia , Microscopia/métodos , Microscopia Eletrônica/métodos , Mitocôndrias/metabolismo , Fagócitos/metabolismo , Fagócitos/fisiologia , Fagocitose/imunologia , Propídio/química , Transdução de Sinais
11.
Mol Immunol ; 131: 171-179, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33461764

RESUMO

Alzheimer's disease (AD) is characterized by the accumulation in the brain of extracellular amyloid ß (Aß) plaques as well as intraneuronal inclusions (neurofibrillary tangles) consisting of total tau and phosphorylated tau. Also present are dystrophic neurites, loss of synapses, neuronal death, and gliosis. AD genetic studies have highlighted the importance of inflammation in this disease by identifying several risk associated immune response genes, including TREM2. TREM2 has been strongly implicated in basic microglia function including, phagocytosis, apoptosis, and the inflammatory response to Aß in mouse brain and primary cells. These studies show that microglia are key players in the response to Aß and in the accumulation of AD pathology. However, details are still missing about which apoptotic or inflammatory factors rely on TREM2 in their response to Aß, especially in human cell lines. Given these previous findings our hypothesis is that TREM2 influences the response to Aß toxicity by enhancing phagocytosis and inhibiting both the BCL-2 family of apoptotic proteins and pro-inflammatory cytokines. Aß42 treatment of the human microglial cell line, HMC3 cells, was performed and TREM2 was overexpressed or silenced and the phagocytosis, apoptosis and inflammatory response were evaluated. Results indicate that a robust phagocytic response to Aß after 24 h requires TREM2 in HMC3 cells. Also, TREM2 inhibits Aß induced apoptosis by activating the Mcl-1/Bim complex. TREM2 is involved in activation of IP-10, MIP-1a, and IL-8, while it inhibits FGF-2, VEGF and GRO. Taken together, TREM2 plays a role in enhancing the microglial functional response to Aß toxicity in HMC3 cells. This novel information suggests that therapeutic strategies that seek to activate TREM2 may not only enhance phagocytosis and inhibit apoptosis, but may also inhibit beneficial inflammatory factors, emphasizing the need to define TREM2-related inflammatory activity in not only mouse models of AD, but also in human AD.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Apoptose/fisiologia , Inflamação/metabolismo , Glicoproteínas de Membrana/metabolismo , Fagócitos/metabolismo , Receptores Imunológicos/metabolismo , Doença de Alzheimer/metabolismo , Encéfalo/metabolismo , Linhagem Celular , Linhagem Celular Tumoral , Células Hep G2 , Humanos , Microglia/metabolismo , Fagocitose/fisiologia , Placa Amiloide/metabolismo , Células THP-1 , Células U937
12.
J Neuroimmunol ; 353: 577496, 2021 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-33517251

RESUMO

Microglia-driven neuroinflammation contributes to neurodegenerative diseases. Mitochondrial phospholipid cardiolipin acts as a signaling molecule when released from damaged cells. We demonstrate that extracellular cardiolipin induces the secretion of monocyte chemoattractant protein-1 and interferon gamma-induced protein 10 by resting microglia while inhibiting secretion of cytokines by microglia stimulated with lipopolysaccharide, amyloid Aß42 peptides, or α-synuclein. Extracellular cardiolipin also induces nitric oxide secretion by microglia-like cells and upregulates microglial phagocytosis. By using blocking antibodies, we determine that toll-like receptor 4 mediates the latter effect. Under physiological and pathological conditions characterized by cell death, extracellularly released cardiolipin may regulate immune responses of microglia.


Assuntos
Cardiolipinas/metabolismo , Citocinas/metabolismo , Microglia/metabolismo , Fagocitose/fisiologia , Receptor 4 Toll-Like/metabolismo , Animais , Cardiolipinas/imunologia , Citocinas/imunologia , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Microglia/imunologia , Células THP-1 , Receptor 4 Toll-Like/imunologia
13.
J Neurosci ; 41(5): 823-833, 2021 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-33468571

RESUMO

Phagocytic activity of glial cells is essential for proper nervous system sculpting, maintenance of circuitry, and long-term brain health. Glial engulfment of apoptotic cells and superfluous connections ensures that neuronal connections are appropriately refined, while clearance of damaged projections and neurotoxic proteins in the mature brain protects against inflammatory insults. Comparative work across species and cell types in recent years highlights the striking conservation of pathways that govern glial engulfment. Many signaling cascades used during developmental pruning are re-employed in the mature brain to "fine tune" synaptic architecture and even clear neuronal debris following traumatic events. Moreover, the neuron-glia signaling events required to trigger and perform phagocytic responses are impressively conserved between invertebrates and vertebrates. This review offers a compare-and-contrast portrayal of recent findings that underscore the value of investigating glial engulfment mechanisms in a wide range of species and contexts.


Assuntos
Encéfalo/citologia , Encéfalo/crescimento & desenvolvimento , Comunicação Celular/fisiologia , Neuroglia/fisiologia , Neurônios/fisiologia , Fagocitose/fisiologia , Animais , Humanos , Especificidade da Espécie
14.
Arterioscler Thromb Vasc Biol ; 41(3): e144-e159, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33406854

RESUMO

OBJECTIVE: ODC (ornithine decarboxylase)-dependent putrescine synthesis promotes the successive clearance of apoptotic cells (ACs) by macrophages, contributing to inflammation resolution. However, it remains unknown whether ODC is required for other arms of the resolution program. Approach and Results: RNA sequencing of ODC-deficient macrophages exposed to ACs showed increases in mRNAs associated with heightened inflammation and decreases in mRNAs related to resolution and repair compared with WT (wild type) macrophages. In zymosan peritonitis, myeloid ODC deletion led to delayed clearance of neutrophils and a decrease in the proresolving cytokine, IL (interleukin)-10. Nanoparticle-mediated silencing of macrophage ODC in a model of atherosclerosis regression lowered IL-10 expression, decreased efferocytosis, enhanced necrotic core area, and reduced fibrous cap thickness. Mechanistically, ODC deletion lowered basal expression of MerTK (MER tyrosine-protein kinase)-an AC receptor-via a histone methylation-dependent transcriptional mechanism. Owing to lower basal MerTK, subsequent exposure to ACs resulted in lower MerTK-Erk (extracellular signal-regulated kinase) 1/2-dependent IL-10 production. Putrescine treatment of ODC-deficient macrophages restored the expression of both MerTK and AC-induced IL-10. CONCLUSIONS: These findings demonstrate that ODC-dependent putrescine synthesis in macrophages maintains a basal level of MerTK expression needed to optimally resolve inflammation upon subsequent AC exposure. Graphic Abstract: A graphic abstract is available for this article.


Assuntos
Ornitina Descarboxilase/metabolismo , Putrescina/biossíntese , c-Mer Tirosina Quinase/metabolismo , Animais , Apoptose/fisiologia , Aterosclerose/metabolismo , Aterosclerose/patologia , Células Cultivadas , Técnicas de Inativação de Genes , Histonas/metabolismo , Inflamação/metabolismo , Inflamação/patologia , Interleucina-10/biossíntese , Sistema de Sinalização das MAP Quinases , Macrófagos/citologia , Macrófagos/metabolismo , Camundongos , Camundongos Knockout , Modelos Biológicos , Ornitina Descarboxilase/deficiência , Ornitina Descarboxilase/genética , Fagocitose/fisiologia , c-Mer Tirosina Quinase/genética
15.
Diabetes ; 70(2): 538-548, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33158932

RESUMO

Obesity is associated with chronic low-grade inflammation of visceral adipose tissue (AT) characterized by an increasing number of AT macrophages (ATMs) and linked to type 2 diabetes. AT inflammation is histologically indicated by the formation of so-called crown-like structures, as ATMs accumulate around dying adipocytes, and the occurrence of multinucleated giant cells (MGCs). However, to date, the function of MGCs in obesity is unknown. Therefore, the aim of this study was to characterize MGCs in AT and unravel the function of these cells. We demonstrated that MGCs occurred in obese patients and after 24 weeks of a high-fat diet in mice, accompanying signs of AT inflammation and then representing ∼3% of ATMs in mice. Mechanistically, we found evidence that adipocyte death triggered MGC formation. Most importantly, MGCs in obese AT had a higher capacity to phagocytize oversized particles, such as adipocytes, as shown by live imaging of AT, 45-µm bead uptake ex vivo, and higher lipid content in vivo. Finally, we showed that interleukin-4 treatment was sufficient to increase the number of MGCs in AT, whereas other factors may be more important for endogenous MGC formation in vivo. Most importantly, our data suggest that MGCs are specialized for clearance of dead adipocytes in obesity.


Assuntos
Adipócitos/metabolismo , Tecido Adiposo/metabolismo , Células Gigantes/metabolismo , Obesidade/metabolismo , Fagocitose/fisiologia , Adipócitos/patologia , Tecido Adiposo/patologia , Animais , Dieta Hiperlipídica , Células Gigantes/patologia , Humanos , Inflamação/metabolismo , Inflamação/patologia , Camundongos , Obesidade/patologia
16.
Exp Parasitol ; 220: 107968, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32781093

RESUMO

The parasitic protozoan Leishmania infantum resides primarily in macrophages throughout mammalian infection. Infection is initiated by deposition of the metacyclic promastigote into the dermis of a mammalian host by the sand fly vector. Promastigotes enter macrophages by ligating surface receptors such as complement receptor 3 (CR3), inducing phagocytosis of the parasite. At the binding site of metacyclic promastigotes, we observed large asymmetrical aggregates of macrophage membrane with underlying actin, resembling membrane ruffles. Actin accumulation was observed at the point of initial contact, before phagosome formation and accumulation of peri-phagosomal actin. Ruffle-like structures did not form during phagocytosis of attenuated promastigotes or during phagocytosis of the intracellular amastigote form of L. infantum. Entry of promastigotes through massive actin accumulation was associated with a subsequent delay in fusion of the parasitophorous vacuole (PV) with the lysosomal markers LAMP-1 and Cathepsin D. Actin accumulation was also associated with entry through CR3, since macrophages from CD11b knockout (KO) mice did not form massive aggregates of actin during phagocytosis of metacyclic promastigotes. Furthermore, intracellular survival of L. infantum was significantly decreased in CD11b KO compared to wild type macrophages, although entry rates were similar. We conclude that both promastigote virulence and host cell CR3 are needed for the formation of ruffle-like membrane structures at the site of metacyclic promastigote phagocytosis, and that formation of actin-rich aggregates during entry correlates with the intracellular survival of virulent promastigotes.


Assuntos
Actinas/metabolismo , Leishmania infantum/fisiologia , Leishmaniose Visceral/parasitologia , Antígeno de Macrófago 1/fisiologia , Fagocitose/fisiologia , Animais , Catepsina D/metabolismo , Membrana Celular/ultraestrutura , Cricetinae , Humanos , Leishmania infantum/patogenicidade , Leishmania infantum/ultraestrutura , Proteína 1 de Membrana Associada ao Lisossomo/metabolismo , Macrófagos/parasitologia , Masculino , Mesocricetus , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Microscopia Confocal , Vacúolos/parasitologia , Virulência
17.
Metabolism ; 114: 154412, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33164859

RESUMO

BACKGROUND: The delayed repair process in the aging diabetic population is becoming an alarming public health concern. ICAM-1 plays an important role in orchestrating the repair process by mediating neutrophil recruitment and phagocytosis. However, little is known about the role of ICAM-1 in aging diabetic repair. METHODS: By causing injury in aging diabetic mice with ICAM-1 deletion (AD-ICAM-1-/-), we found that AD-ICAM-1-/- mice exhibited a delayed repair process with incomplete re-epithelialization and reduced angiogenesis. Additionally, high-throughput Illumina sequencing was performed to evaluate the microbiota of such mice. RESULTS: The results indicate that the microbiota of the AD-ICAM-1-/- injury site differed taxonomically at both the phylum and genus levels. Neutrophil recruitment and phagocytic function were also reduced in the AD-ICAM-1-/- group. Notably, major inflammatory biomarker expression was also detected in AD-ICAM-1-/- injured tissue. CONCLUSIONS: Overall, this study demonstrated that AD-ICAM-1-/- mice exhibit delayed repair. In addition, neutrophil recruitment and phagocytic activity were impaired in the AD-ICAM-1-/- group, which may have allowed microbes to colonize the injury site.


Assuntos
Envelhecimento/metabolismo , Diabetes Mellitus Experimental/metabolismo , Molécula 1 de Adesão Intercelular/metabolismo , Infiltração de Neutrófilos/fisiologia , Animais , Movimento Celular/fisiologia , Molécula 1 de Adesão Intercelular/genética , Camundongos , Camundongos Knockout , Microbiota , Fagocitose/fisiologia
18.
Proc Natl Acad Sci U S A ; 117(51): 32679-32690, 2020 12 22.
Artigo em Inglês | MEDLINE | ID: mdl-33293423

RESUMO

Intracerebral hemorrhage (ICH) is a devastating form of stroke affecting millions of people worldwide. Parenchymal hematoma triggers a series of reactions leading to primary and secondary brain injuries and permanent neurological deficits. Microglia and macrophages carry out hematoma clearance, thereby facilitating functional recovery after ICH. Here, we elucidate a pivotal role for the interleukin (IL)-4)/signal transducer and activator of transcription 6 (STAT6) axis in promoting long-term recovery in both blood- and collagenase-injection mouse models of ICH, through modulation of microglia/macrophage functions. In both ICH models, STAT6 was activated in microglia/macrophages (i.e., enhanced expression of phospho-STAT6 in Iba1+ cells). Intranasal delivery of IL-4 nanoparticles after ICH hastened STAT6 activation and facilitated hematoma resolution. IL-4 treatment improved long-term functional recovery in young and aged male and young female mice. In contrast, STAT6 knockout (KO) mice exhibited worse outcomes than WT mice in both ICH models and were less responsive to IL-4 treatment. The construction of bone marrow chimera mice demonstrated that STAT6 KO in either the CNS or periphery exacerbated ICH outcomes. STAT6 KO impaired the capacity of phagocytes to engulf red blood cells in the ICH brain and in primary cultures. Transcriptional analyses identified lower level of IL-1 receptor-like 1 (ST2) expression in microglia/macrophages of STAT6 KO mice after ICH. ST2 KO diminished the beneficial effects of IL-4 after ICH. Collectively, these data confirm the importance of IL-4/STAT6/ST2 signaling in hematoma resolution and functional recovery after ICH. Intranasal IL-4 treatment warrants further investigation as a clinically feasible therapy for ICH.


Assuntos
Hemorragia Cerebral/metabolismo , Hematoma/metabolismo , AVC Hemorrágico/metabolismo , Interleucina-4/metabolismo , Fator de Transcrição STAT6/metabolismo , Animais , Hemorragia Cerebral/tratamento farmacológico , Hemorragia Cerebral/patologia , Modelos Animais de Doenças , Feminino , Hematoma/tratamento farmacológico , Hematoma/patologia , AVC Hemorrágico/tratamento farmacológico , AVC Hemorrágico/patologia , Proteína 1 Semelhante a Receptor de Interleucina-1/genética , Proteína 1 Semelhante a Receptor de Interleucina-1/metabolismo , Interleucina-4/administração & dosagem , Interleucina-4/farmacologia , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microglia/metabolismo , Teste do Labirinto Aquático de Morris/efeitos dos fármacos , Fagocitose/efeitos dos fármacos , Fagocitose/fisiologia , Teste de Desempenho do Rota-Rod , Fator de Transcrição STAT6/genética , Transdução de Sinais
20.
Sci Rep ; 10(1): 18936, 2020 11 03.
Artigo em Inglês | MEDLINE | ID: mdl-33144615

RESUMO

Transplantation of peripheral nervous system glia is being explored for treating neural injuries, in particular central nervous system injuries. These glia, olfactory ensheathing cells (OECs) and Schwann cells (SCs), are thought to aid regeneration by clearing necrotic cells, (necrotic bodies, NBs), as well as myelin debris. The mechanism by which the glia phagocytose and traffic NBs are not understood. Here, we show that OECs and SCs recognize phosphatidylserine on NBs, followed by engulfment and trafficking to endosomes and lysosomes. We also showed that both glia can phagocytose and process myelin debris. We compared the time-course of glial phagocytosis (of both NBs and myelin) to that of macrophages. Internalization and trafficking were considerably slower in glia than in macrophages, and OECs were more efficient phagocytes than SCs. The two glial types also differed regarding their cytokine responses after NB challenge. SCs produced low amounts of the pro-inflammatory cytokine TNF-α while OECs did not produce detectable TNF-α. Thus, OECs have a higher capacity than SCs for phagocytosis and trafficking, whilst producing lower amounts of pro-inflammatory cytokines. These findings suggest that OEC transplantation into the injured nervous system may lead to better outcomes than SC transplantation.


Assuntos
Fagocitose/fisiologia , Células de Schwann/metabolismo , Animais , Western Blotting , Morte Celular/genética , Morte Celular/fisiologia , Imunofluorescência , Macrófagos/metabolismo , Camundongos , Camundongos Transgênicos , Neuroglia/citologia , Neuroglia/metabolismo , Neurociências , Fagocitose/genética , Fosfatidilserinas/metabolismo
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