RESUMO
The presence of gallstones (cholelithiasis) is a highly prevalent and severe disease and one of the leading causes of hospital admissions worldwide. Due to its substantial health impact, we investigated the biological mechanisms that lead to the formation and growth of gallstones. We show that gallstone assembly essentially requires neutrophil extracellular traps (NETs). We found consistent evidence for the presence of NETs in human and murine gallstones and describe an immune-mediated process requiring activation of the innate immune system for the formation and growth of gallstones. Targeting NET formation via inhibition of peptidyl arginine deiminase type 4 or abrogation of reactive oxygen species (ROS) production, as well as damping of neutrophils by metoprolol, effectively inhibit gallstone formation in vivo. Our results show that after the physicochemical process of crystal formation, NETs foster their assembly into larger aggregates and finally gallstones. These insights provide a feasible therapeutic concept to prevent cholelithiasis in patients at risk.
Assuntos
Armadilhas Extracelulares/imunologia , Cálculos Biliares/imunologia , Neutrófilos/imunologia , Animais , Feminino , Humanos , Imunidade Inata/imunologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Espécies Reativas de Oxigênio/imunologiaRESUMO
Pacifier use during childhood has been hypothesized to interfere with language processing, but, to date, there is limited evidence revealing detrimental effects of prolonged pacifier use on infant vocabulary learning. In the present study, parents of 12- and 24-month-old infants were recruited in Oslo (Norway). The sample included 1187 monolingual full-term born (without visual, auditory, or cognitive impairments) infants: 452 (230 girls; 222 boys) 12-month-olds and 735 (345 girls; 390 boys) 24-month-olds. Parents filled out an online Norwegian Communicative Development Inventory (CDI), which assesses the vocabulary in comprehension and production for 12-month-old infants and in production only for 24-month-old infants. CDI scores were transformed into age- and sex-adjusted percentiles using Norwegian norms. Additionally, parents retrospectively reported their child's daytime pacifier use, in hours, at 2-month intervals, from birth to the assessment date. Maternal education was used to control, in the analyses, for the socio-economic status. We found that greater pacifier use in an infant's lifespan was associated with lower vocabulary size. Pacifier use later in life was more negatively associated with vocabulary size than precocious use, and increased the odds of being a low language scorer. In sum, our study moves beyond the findings of momentary effects of experimentally induced "impairment" in articulators' movement on speech perception and suggests that, from 12 months of age, constraints on the infant's speech articulators (pacifier use) may be negatively associated with word comprehension and production. RESEARCH HIGHLIGHT: We examined the relationship between pacifier use and vocabulary sizes in production at 24 months of age and comprehension and production at 12 months of age. Lifespan Pacifier Use (LPU) was negatively correlated with vocabulary sizes in comprehension and production among 12-month-old infants and negatively correlated with production for 24-month-olds. Later pacifier use was found to be more negatively correlated with vocabulary size in infants, as compared to more precocious use. The amount of pacifier use in the 2 months prior to a child's second birthday was predictive of a higher prevalence of low vocabulary scores in 24-month-olds.
Assuntos
Desenvolvimento da Linguagem , Chupetas , Vocabulário , Humanos , Lactente , Feminino , Masculino , Estudos Transversais , Pré-Escolar , NoruegaRESUMO
Neutrophil extracellular traps (NETs) are extracellular structures, composed of nuclear DNA and various proteins released from neutrophils. Evidence is growing that NETs exert manifold functions in infection, immunity and cancer. Recently, NETs have been detected in colorectal cancer (CRC) tissues, but their association with disease progression and putative functional impact on tumourigenesis remained elusive. Using high-resolution stimulated emission depletion (STED) microscopy, we showed that citrullinated histone H3 (H3cit) is sufficient to specifically detect citrullinated NETs in colon cancer tissues. Among other evidence, this was supported by the close association of H3cit with de-condensed extracellular DNA, the hallmark of NETs. Extracellular DNA was reliably differentiated from nuclear condensed DNA by staining with an anti-DNA antibody, providing a novel and valuable tool to detect NETs in formalin-fixed paraffin-embedded tissues. Using these markers, the clinical association of NETs was investigated in a cohort of 85 patients with colon cancer. NETs were frequently detected (37/85, 44%) in colon cancer tissue sections and preferentially localised either only in the tumour centre or both in the tumour centre and the invasive front. Of note, citrullinated NETs were significantly associated with high histopathological tumour grades and lymph node metastasis. In vitro, purified NETs induced filopodia formation and cell motility in CRC cell lines. This was associated with increased expression of mesenchymal marker mRNAs (vimentin [VIM], fibronectin [FN1]) and epithelial-mesenchymal transition promoting transcription factors (ZEB1, Slug [SNAI2]), as well as decreased expression of the epithelial markers E-cadherin (CDH1) and epithelial cell adhesion molecule (EPCAM). These findings indicated that NETs activate an epithelial-mesenchymal transition-like process in CRC cells and may contribute to the metastatic progression of CRC. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.
Assuntos
Neoplasias do Colo , Armadilhas Extracelulares , Biomarcadores/metabolismo , Neoplasias do Colo/metabolismo , DNA , Transição Epitelial-Mesenquimal , Armadilhas Extracelulares/metabolismo , Humanos , NeutrófilosRESUMO
During inflammatory responses, neutrophils enter the sites of attack where they execute various defense mechanisms. They (I) phagocytose microorganisms, (II) degranulate to release cytokines, (III) recruit various immune cells by cell-type specific chemokines, (IV) secrete anti-microbials including lactoferrin, lysozyme, defensins and reactive oxygen species, and (V) release DNA as neutrophil extracellular traps (NETs). The latter originates from mitochondria as well as from decondensed nuclei. This is easily detected in cultured cells by staining of DNA with specific dyes. However, in tissues sections the very high fluorescence signals emitted from the condensed nuclear DNA hamper the detection of the widespread, extranuclear DNA of the NETs. In contrast, when we employ anti-DNA-IgM antibodies, they are unable to penetrate deep into the tightly packed DNA of the nucleus, and we observe a robust signal for the extended DNA patches of the NETs. To validate anti-DNA-IgM, we additionally stained the sections for the NET-markers histone H2B, myeloperoxidase, citrullinated histone H3, and neutrophil elastase. Altogether, we have described a fast one-step procedure for the detection of NETs in tissue sections, which provides new perspectives to characterize neutrophil-associated immune reactions in disease.
Assuntos
Armadilhas Extracelulares , Neutrófilos , Fagocitose , Histonas , DNA , Imunoglobulina MRESUMO
Vascular occlusions in patients with coronavirus diseases 2019 (COVID-19) have been frequently reported in severe outcomes mainly due to a dysregulation of neutrophils mediating neutrophil extracellular trap (NET) formation. Lung specimens from patients with COVID-19 have previously shown a dynamic morphology, categorized into three types of pleomorphic occurrence based on histological findings in this study. These vascular occlusions in lung specimens were also detected using native endogenous fluorescence or NEF in a label-free method. The three types of vascular occlusions exhibit morphology of DNA rich neutrophil elastase (NE) poor (type I), NE rich DNA poor (type II), and DNA and NE rich (type III) cohort of eleven patients with six males and five females. Age and gender have been presented in this study as influencing variables linking the occurrence of several occlusions with pleomorphic contents within a patient specimen and amongst them. This study reports the categorization of pleomorphic occlusions in patients with COVID-19 and the detection of these occlusions in a label-free method utilizing NEF.
Assuntos
COVID-19 , Armadilhas Extracelulares , Doenças Vasculares , Masculino , Feminino , Humanos , COVID-19/complicações , COVID-19/patologia , SARS-CoV-2 , Pulmão/patologia , Neutrófilos/patologia , Doenças Vasculares/patologiaRESUMO
Diurnal clearance phagocytosis by the retinal pigment epithelium (RPE) is a conserved efferocytosis process whose binding step is mediated by αvß5 integrin receptors. Two related annexins, A5 (ANXA5) and A6 (ANXA6), share an αvß5 integrin-binding motif. Here, we report that ANXA5, but not ANXA6, regulates the binding capacity for spent photoreceptor outer segment fragments or apoptotic cells by fibroblasts and RPE. Similar to αvß5-deficient RPE, ANXA5-/- RPE in vivo lacks the diurnal burst of phagocytosis that follows photoreceptor shedding in wild-type retina. Increasing ANXA5 in cells lacking αvß5 or increasing αvß5 in cells lacking ANXA5 does not affect particle binding. Association of cytosolic ANXA5 and αvß5 integrin in RPE in culture and in vivo further supports their functional interdependence. Silencing ANXA5 is sufficient to reduce levels of αvß5 receptors at the apical phagocytic surface of RPE cells. The effect of ANXA5 on surface αvß5 and on particle binding requires the C-terminal ANXA5 annexin repeat but not its unique N-terminus. These results identify a novel role for ANXA5 specifically in the recognition and binding step of clearance phagocytosis, which is essential to retinal physiology.This article has an associated First Person interview with the first author of the paper.
Assuntos
Anexina A5/metabolismo , Apoptose , Fagocitose , Células Fotorreceptoras de Vertebrados/metabolismo , Receptores de Vitronectina/metabolismo , Epitélio Pigmentado da Retina/metabolismo , Animais , Anexina A5/genética , Fibroblastos/citologia , Fibroblastos/metabolismo , Camundongos , Camundongos Knockout , Células Fotorreceptoras de Vertebrados/citologia , Ratos , Ratos Sprague-Dawley , Receptores de Vitronectina/genética , Epitélio Pigmentado da Retina/citologiaRESUMO
Periodontitis is considered a promoter of many systemic diseases, but the signaling pathways of this interconnection remain elusive. Recently, it became evident that certain microbial challenges promote a heightened response of myeloid cell populations to subsequent infections either with the same or other pathogens. This phenomenon involves changes in the cell epigenetic and transcription, and is referred to as ''trained immunity''. It acts via modulation of hematopoietic stem and progenitor cells (HSPCs). A main modulation driver is the sustained, persistent low-level transmission of lipopolysaccharide from the periodontal pocket into the peripheral blood. Subsequently, the neutrophil phenotype changes and neutrophils become hyper-responsive and prone to boosted formation of neutrophil extracellular traps (NET). Cytotoxic neutrophil proteases and histones are responsible for ulcer formations on the pocket epithelium, which foster bacteremia and endoxemia. The latter promote systemic low-grade inflammation (SLGI), a precondition for many systemic diseases and some of them, e.g., atherosclerosis, diabetes etc., can be triggered by SLGI alone. Either reverting the polarized neutrophils back to the homeostatic state or attenuation of neutrophil hyper-responsiveness in periodontitis might be an approach to diminish or even to prevent systemic diseases.
Assuntos
Doença/etiologia , Endotoxemia/imunologia , Neutrófilos/fisiologia , Periodontite/complicações , Animais , Endotoxemia/metabolismo , Humanos , Lipopolissacarídeos/metabolismo , Periodontite/imunologia , Periodontite/metabolismoRESUMO
Dendritic cells (DCs) are the most effective antigen presenting cells for the development of T cell responses. The only FDA approved DC-based immunotherapy to date is Sipuleucel-T, which utilizes a fusion protein to stimulate DCs ex vivo with GM-CSF and simultaneously deliver the antigen PAP for prostate cancer. This approach is restricted by the breadth of immunity elicited to a single antigen, and to cancers that have a defined tumor associated antigen. Other multi-antigen approaches have been restricted by poor efficacy of vaccine adjuvants. We have developed a vaccine platform that consists of autologous DCs pulsed with cytokine-adjuvanted tumor membrane vesicles (TMVs) made from tumor tissue, that encapsulate the antigenic landscape of individual tumors. Here we test the efficacy of DCs pulsed with TMVs incorporated with glycolipid-anchored immunostimulatory molecules (GPI-ISMs) in HER2-positive and triple negative breast cancer murine models. Pulsing of DCs with TMVs containing GPI-ISMs results in superior uptake of vesicles, DC activation and cytokine production. Adaptive transfer of TMV-pulsed DCs to tumor bearing mice results in the inhibition of tumor growth, reduction in lung metastasis, and an increase in immune cell infiltration into the tumors. These observations suggest that DCs pulsed with TMVs containing GPI-GM-CSF and GPI-IL-12 can be further developed to be used as a personalized immunotherapy platform for cancer treatment.
Assuntos
Antígenos de Neoplasias/imunologia , Citocinas/imunologia , Células Dendríticas/imunologia , Receptor ErbB-2/imunologia , Neoplasias de Mama Triplo Negativas/terapia , Transferência Adotiva , Animais , Vacinas Anticâncer/imunologia , Vacinas Anticâncer/uso terapêutico , Linhagem Celular Tumoral , Células Cultivadas , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Receptor ErbB-2/análise , Neoplasias de Mama Triplo Negativas/imunologia , Neoplasias de Mama Triplo Negativas/patologiaRESUMO
Billions of cells die every day in higher organisms as part of the normal process of tissue homeostasis. During special conditions like in development, acute infections, mechanical injuries, and immunity, cell death is a common denominator and it exerts profound effects in the outcome of these scenarios. To prevent the accumulation of aged, superfluous, infected, damaged and dead cells, professional phagocytes act in a rapid and efficient manner to clear the battle field and avoid spread of the destruction. Neutrophils are the most abundant effector immune cells that extravasate into tissues and can turn injured tissues into gory battle fields. In peace times, neutrophils tend to patrol tissues without provoking inflammatory reactions. We discuss in this review actual and forgotten knowledge about the meaning of cell death during homeostatic processes and drive the attention to the importance of the action of neutrophils during patrolling and for the maintenance or recovery of the homeostatic state once the organism gets attacked or injured, respectively. In this fashion, we disclose several disease conditions that arise as collateral damage of physiological responses to death.
Assuntos
Morte Celular , Homeostase , Imunidade Inata , Inflamação/psicologia , Neutrófilos/imunologia , Animais , Armadilhas Extracelulares/metabolismo , Humanos , Fagócitos/fisiologiaRESUMO
We report here on a one-pot construction of oil-filled hierarchical capsular assemblies using the nanoprecipitation technique. Relying on multicomponent phase diagrams, we show that simultaneous and/or sequential nanoprecipitations involving polymer combinations can be precisely programmed to design a new class of mixed/multilayered multicomponent nanocapsules, with a precise control of the dimensions, shell thickness/composition, and spatial distribution of the building blocks. The simplicity and tunability of this approach are exemplified here with a library of neutral and ionic polysaccharides giving access to a range of functional multilayered nanocarriers of interest for biomedical applications.
Assuntos
Nanocápsulas/química , Polissacarídeos/química , Tecnologia Farmacêutica/métodos , Óleos/química , Polímeros/química , Dióxido de Silício/químicaRESUMO
The critical size for strong interaction of hydrophobic particles with phospholipid bilayers has been predicted to be 10 nm. Because of the wide spreading of nonpolar nanoparticles (NPs) in the environment, we aimed to reveal the ability of living organisms to entrap NPs via formation of neutrophil extracellular traps (NETs). Upon interaction with various cell types and tissues, 10- to 40-nm-sized NPs induce fast (<20 min) damage of plasma membranes and instability of the lysosomal compartment, leading to the immediate formation of NETs. In contrast, particles sized 100-1,000 nm behaved rather inertly. Resulting NET formation (NETosis) was accompanied by an inflammatory reaction intrinsically endowed with its own resolution, demonstrated in lungs and air pouches of mice. Persistence of small NPs in joints caused unremitting arthritis and bone remodeling. Small NPs coinjected with antigen exerted adjuvant-like activity. This report demonstrates a cellular mechanism that explains how small NPs activate the NETosis pathway and drive their entrapping and resolution of the initial inflammatory response.
Assuntos
Armadilhas Extracelulares/metabolismo , Inflamação/patologia , Nanopartículas/química , Tamanho da Partícula , Animais , Membrana Celular/metabolismo , Eritrócitos/metabolismo , Células HeLa , Humanos , Interações Hidrofóbicas e Hidrofílicas , Imunidade , Pulmão/metabolismo , Camundongos Endogâmicos BALB C , Nanodiamantes/química , Nanodiamantes/ultraestrutura , Nanopartículas/ultraestrutura , Neutrófilos/metabolismo , Neutrófilos/ultraestrutura , Espécies Reativas de Oxigênio/metabolismoRESUMO
The ability to control the timing and mode of host cell death plays a pivotal role in microbial infections. Many bacteria use toxins to kill host cells and evade immune responses. Such toxins are unknown in Mycobacterium tuberculosis. Virulent M. tuberculosis strains induce necrotic cell death in macrophages by an obscure molecular mechanism. Here we show that the M. tuberculosis protein Rv3903c (channel protein with necrosis-inducing toxin, CpnT) consists of an N-terminal channel domain that is used for uptake of nutrients across the outer membrane and a secreted toxic C-terminal domain. Infection experiments revealed that CpnT is required for survival and cytotoxicity of M. tuberculosis in macrophages. Furthermore, we demonstrate that the C-terminal domain of CpnT causes necrotic cell death in eukaryotic cells. Thus, CpnT has a dual function in uptake of nutrients and induction of host cell death by M. tuberculosis.
Assuntos
Proteínas da Membrana Bacteriana Externa/metabolismo , Toxinas Bacterianas/metabolismo , Exotoxinas/metabolismo , Mycobacterium tuberculosis/metabolismo , Sequência de Aminoácidos , Animais , Proteínas da Membrana Bacteriana Externa/química , Proteínas da Membrana Bacteriana Externa/genética , Toxinas Bacterianas/química , Toxinas Bacterianas/genética , Linhagem Celular , Exotoxinas/química , Exotoxinas/genética , Genes Bacterianos , Glicerol/metabolismo , Células HEK293 , Humanos , Células Jurkat , Macrófagos/microbiologia , Camundongos , Camundongos Endogâmicos C57BL , Dados de Sequência Molecular , Mutação , Mycobacterium bovis/genética , Mycobacterium bovis/crescimento & desenvolvimento , Mycobacterium bovis/metabolismo , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/patogenicidade , Filogenia , Estrutura Terciária de Proteína , Proteínas Recombinantes/genética , Proteínas Recombinantes/toxicidade , Homologia de Sequência de Aminoácidos , Virulência/genética , Virulência/fisiologiaRESUMO
Osteoporosis can arise in systemic lupus erythematosus (SLE) patients secondary to medication and/or chronic inflammation. To analyze if patients with SLE have phenotypically-impaired osteoclastogenesis, we differentiated ex vivo monocytes from 72 SLE patients and 15 healthy individuals into osteoclasts followed by TRAP staining and counting. We identified a subgroup of SLE patients (45%) with a significantly impaired osteoclast differentiation, relative to the other SLE patients or healthy individuals (OR 11.2; 95% CI 1.4-89.9). A review of medication indicated that patients with osteoclast counts equal to healthy donors were significantly more likely to be treated with mycophenolate mofetil (MMF) compared to patients with impaired osteoclastogenesis. We analyzed expression of RANKL and the MMF target genes IMPDH1 and IMPDH2 in osteoclasts by qPCR, but detected no difference. Since MMF might influence interferon-α (IFNα) and -γ (IFNγ) we measured serum IFNα and IFNγ levels. Patients with very low osteoclast counts also had comparably higher IFNα serum levels than patients with normal osteoclast counts. We conclude that in vitro osteoclastogenesis is impaired in a subgroup of SLE patients. This correlates inversely with MMF treatment and high IFNα serum levels. Further observational study will be required to determine whether this translates into a clinically meaningful effect.
Assuntos
Anti-Inflamatórios não Esteroides/uso terapêutico , Diferenciação Celular , Lúpus Eritematoso Sistêmico/tratamento farmacológico , Lúpus Eritematoso Sistêmico/patologia , Ácido Micofenólico/análogos & derivados , Osteoclastos/citologia , Osteoclastos/patologia , Corticosteroides/uso terapêutico , Contagem de Células Sanguíneas , Estudos de Casos e Controles , Contagem de Células , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , IMP Desidrogenase/genética , IMP Desidrogenase/metabolismo , Interferon-alfa/sangue , Interferon-alfa/metabolismo , Lúpus Eritematoso Sistêmico/sangue , Lúpus Eritematoso Sistêmico/genética , Masculino , Ácido Micofenólico/uso terapêutico , Receptor Ativador de Fator Nuclear kappa-B/genética , Receptor Ativador de Fator Nuclear kappa-B/metabolismo , Resultado do TratamentoRESUMO
Chronic graft-versus-host disease (cGVHD) is a prognosis limiting complication of allogeneic stem cell transplantation. The molecular mechanisms underlying cGVHD are incompletely understood, and targeted therapies are not yet established for clinical use. Here we examined the role of the hedgehog pathway in sclerodermatous cGVHD. Hedgehog signaling was activated in human and murine cGVHD with increased expression of sonic hedgehog and accumulation of the transcription factors Gli-1 and Gli-2. Treatment with LDE223, a highly selective small-molecule antagonist of the hedgehog coreceptor Smoothened (Smo), abrogated the activation of hedgehog signaling and protected against experimental cGVHD. Preventive therapy with LDE223 almost completely impeded the development of clinical and histologic features of sclerodermatous cGVHD. Treatment with LDE223 was also effective, when initiated after the onset of clinical manifestations of cGVHD. Hedgehog signaling stimulated the release of collagen from cultured fibroblasts but did not affect leukocyte influx in murine cGVHD, suggesting direct, leukocyte-independent stimulatory effects on fibroblasts as the pathomechanism of hedgehog signaling in cGVHD. Considering the high morbidity of cGVHD, the current lack of efficient molecular therapies for clinical use, and the availability of well-tolerated inhibitors of Smo, targeting hedgehog signaling might be a novel strategy for clinical trials in cGVHD.
Assuntos
Compostos de Bifenilo/uso terapêutico , Modelos Animais de Doenças , Doença Enxerto-Hospedeiro/prevenção & controle , Proteínas Hedgehog/antagonistas & inibidores , Receptores Acoplados a Proteínas G/antagonistas & inibidores , Escleroderma Sistêmico/prevenção & controle , Animais , Transplante de Medula Óssea , Doença Crônica , Colágeno/metabolismo , Feminino , Fibroblastos/efeitos dos fármacos , Fibroblastos/patologia , Doença Enxerto-Hospedeiro/metabolismo , Doença Enxerto-Hospedeiro/patologia , Proteínas Hedgehog/genética , Proteínas Hedgehog/metabolismo , Humanos , Técnicas Imunoenzimáticas , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase em Tempo Real , Receptores Acoplados a Proteínas G/metabolismo , Escleroderma Sistêmico/metabolismo , Escleroderma Sistêmico/patologia , Receptor SmoothenedRESUMO
Hydrogen sulfide (H2S) is an important signaling molecule with physiological endpoints similar to those of nitric oxide (NO). Growing interest in its physiological roles and pharmacological potential has led to large sets of contradictory data. The principle cause of these discrepancies can be the common neglect of some of the basic H2S chemistry. This study investigates how the experimental outcome when working with H2S depends on its source and dose and the methodology employed. We show that commercially available NaHS should be avoided and that traces of metal ions should be removed because these can reduce intramolecular disulfides and change protein structure. Furthermore, high H2S concentrations may lead to a complete inhibition of cell respiration, mitochondrial membrane potential depolarization and superoxide generation, which should be considered when discussing the biological effects observed upon treatment with high concentrations of H2S. In addition, we provide chemical evidence that H2S can directly react with superoxide. H2S is also capable of reducing cytochrome c(3+) with the concomitant formation of superoxide. H2S does not directly react with nitrite but with NO electrodes that detect H2S. In addition, H2S interferes with the Griess reaction and should therefore be removed from the solution by Cd(2+) or Zn(2+) precipitation prior to nitrite quantification. 2-Phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (PTIO) is reduced by H2S, and its use should be avoided in combination with H2S. All these constraints must be taken into account when working with H2S to ensure valid data.
Assuntos
Artefatos , Sulfeto de Hidrogênio/metabolismo , Sulfeto de Hidrogênio/farmacologia , Projetos de Pesquisa/normas , Linhagem Celular Tumoral , Óxidos N-Cíclicos/química , Óxidos N-Cíclicos/metabolismo , Humanos , Sulfeto de Hidrogênio/análise , Sulfeto de Hidrogênio/química , Imidazóis/química , Imidazóis/metabolismo , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Óxido Nítrico/análise , Superóxidos/química , Superóxidos/metabolismoRESUMO
Background/Objectives: In patients diagnosed with uncomplicated acute appendicitis (UAA), the absence of calcified deposits or stones, called appendicoliths, often leads to consideration of non-operative treatment (NOT), despite the notable treatment failure rate associated with this approach. Previous research has indirectly estimated the prevalence of appendicoliths to range between 15% and 38% retrospectively by CT scan, intraoperative palpation, and pathology report, thereby potentially missing certain concrements. Our hypothesis proposes that this reported prevalence significantly underestimates the occurrence of appendicoliths, which could explain the high failure rate of 29% of patients with appendicitis observed with NOT. Methods: In our prospective study, conducted with a cohort of 56 adult patients diagnosed with acute appendicitis (AA), we employed intraoperative extracorporeal incisions of the vermiform appendix, in addition to standard diagnostic methods. Results: Our findings revealed 50% more appendicoliths by intraoperative incision (n = 36, p < 0.001) compared to preoperative imaging (n = 24). Appendicoliths were present in 71.4% (n = 40, p < 0.001) of AA patients. Conclusions: These results suggest that conventional diagnostic procedures plausibly underestimate the actual prevalence of appendicoliths, potentially elucidating the frequent treatment failures observed in NOT approaches applied to patients with UAA.
RESUMO
Inappropriate clearance of apoptotic remnants is considered to be the primary cause of systemic autoimmune diseases, like systemic lupus erythematosus. Here we demonstrate that apoptotic cells release distinct types of subcellular membranous particles (scMP) derived from the endoplasmic reticulum (ER) or the plasma membrane. Both types of scMP exhibit desialylated glycotopes resulting from surface exposure of immature ER-derived glycoproteins or from surface-borne sialidase activity, respectively. Sialidase activity is activated by caspase-dependent mechanisms during apoptosis. Cleavage of sialidase Neu1 by caspase 3 was shown to be directly involved in apoptosis-related increase of surface sialidase activity. ER-derived blebs possess immature mannosidic glycoepitopes and are prioritized by macrophages during clearance. Plasma membrane-derived blebs contain nuclear chromatin (DNA and histones) but not components of the nuclear envelope. Existence of two immunologically distinct types of apoptotic blebs may provide new insights into clearance-related diseases.
Assuntos
Apoptose , Micropartículas Derivadas de Células/metabolismo , Macrófagos/citologia , Macrófagos/metabolismo , Apoptose/efeitos dos fármacos , Caspase 3/farmacologia , Caspase 8/farmacologia , Linhagem Celular Tumoral , Micropartículas Derivadas de Células/efeitos dos fármacos , Retículo Endoplasmático/efeitos dos fármacos , Retículo Endoplasmático/metabolismo , Galactose/metabolismo , Glicoproteínas/metabolismo , Glicosilação/efeitos dos fármacos , Humanos , Macrófagos/efeitos dos fármacos , Manose/metabolismo , Neuraminidase/metabolismoRESUMO
The presence of autoantibodies against immunoregulatory effectors can be relevant for onset and/or the progression of autoimmune disease. Emerging insights into an immunological activity profile including a role as opsonins give reason to systematically monitor sera of patients for immunoglobulin G (IgG) autoantibodies, preferably for several galectins at the same time. Here, we report on a study of chronic inflammatory rheumatic diseases, i.e. systemic lupus erythematosus (SLE; pilot cohort p, n = 40; confirmation cohort c, n = 109), rheumatoid arthritis (RA; p, n = 32; c, n = 25) and primary antiphospholipid syndrome (APS; c, n = 64). Enzyme-linked immunosorbent assay-based series using galectin-1, -2, -3, -4, -7, -8 and -9 and natural processing products, i.e. the truncated version of galectin-3 and the N-terminal domains of galectin-4, -8 and -9, were performed. Normal healthy donors (p, n = 20; c, n = 21) and patients with paraproteins (c, n = 19) served as controls. Highly significant optical density-value readings for IgG autoantibodies were consistently detected for the proto-type galectin-7 (SLE) and the tandem repeat-type galectin-8 and -9 (SLE and RA). Their presence was independent from the autoantibody status against double-stranded DNA (for patients with SLE) or a rheumatoid factor (for patients with RA), respectively. Importantly, anti-galectin-2 autoantibodies highly significantly correlated with the appearance of a secondary APS in patients with SLE so that this parameter may serve as an additional biomarker for APS. Equally of note, the presence of IgG autoantibodies against galectins capable to act as an opsonin may contribute to a sustained immune dysregulation in patients with chronic inflammatory rheumatic diseases.
Assuntos
Síndrome Antifosfolipídica/imunologia , Autoanticorpos/imunologia , Galectinas/imunologia , Lúpus Eritematoso Sistêmico/imunologia , Autoanticorpos/sangue , Biomarcadores/sangue , Estudos de Coortes , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Masculino , Fator Reumatoide/sangueRESUMO
Healthy cells exhibit an asymmetric plasma membrane with phosphatidylserine (PS) located on the cytoplasmic leaflet of the plasma membrane bilayer. Annexin A5-FITC, a PS binding protein, is commonly used to evaluate apoptosis in flow cytometry. PS exposed by apoptotic cells serves as a major 'eat-me' signal for phagocytes. Although exposition of PS has been observed after alternative stimuli, no clearance of viable, PS exposing cells has been detected. Thus, besides PS exposure, membranes of viable and apoptotic cells might exhibit specific characteristics. Here, we show that Annexin A5 binds in a cooperative manner to different types of dead cells. Shrunken apoptotic cells thereby showed the highest Hill coefficient values. Contrarily, parafomaldehyde fixation of apoptotic cells completely abrogates the cooperativity effect seen with dead and dying cells. We tend to speculate that the cooperative binding of Annexin A5 to the membranes of apoptotic cells reflects higher fluidity of the exposed membranes facilitating PS clustering.
Assuntos
Anexina A5/metabolismo , Apoptose , Membrana Celular/metabolismo , Fluoresceína-5-Isotiocianato/análogos & derivados , Fosfatidilserinas/metabolismo , Células Cultivadas , Citometria de Fluxo , Fluoresceína-5-Isotiocianato/metabolismo , Humanos , Ligação ProteicaRESUMO
Apoptotic cell death and the clearance of dying cells play an important and physiological role in embryonic development and normal tissue turnover. In contrast to necrosis, apoptosis proceeds in an anti-inflammatory manner. It is orchestrated by the timed release and/or exposure of so-called 'find-me', 'eat me' and 'tolerate me' signals. Mononuclear phagocytes are attracted by various 'find-me' signals, including proteins, nucleotides, and phospholipids released by the dying cell, whereas the involvement of granulocytes is prevented via 'stay away' signals. The exposure of anionic phospholipids like phosphatidylserine (PS) by apoptotic cells on the outer leaflet of the plasma membrane is one of the main 'eat me' signals. PS is recognized by a number of innate receptors as well as by soluble bridging molecules on the surface of phagocytes. Importantly, phagocytes are able to discriminate between viable and apoptotic cells both exposing PS. Due to cytoskeleton remodeling PS has a higher lateral mobility on the surfaces of apoptotic cells thereby promoting receptor clustering on the phagocyte. PS not only plays an important role in the engulfment process, but also acts as 'tolerate me' signal inducing the release of anti-inflammatory cytokines by phagocytes. An efficient and fast clearance of apoptotic cells is required to prevent secondary necrosis and leakage of intracellular danger signals into the surrounding tissue. Failure or prolongation of the clearance process leads to the release of intracellular antigens into the periphery provoking inflammation and development of systemic inflammatory autoimmune disease like systemic lupus erythematosus. Here we review the current findings concerning apoptosis-inducing pathways, important players of apoptotic cell recognition and clearance as well as the role of membrane remodeling in the engulfment of apoptotic cells by phagocytes.