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1.
J Chem Phys ; 161(2)2024 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-38990119

RESUMO

We present a detailed study on the effects of oxygen on the photoluminescence properties of CdSe/CdS quantum dots (QDs). We investigated the role of oxygen by performing confocal measurements on thin films as well as on single particles while rapidly exchanging the gaseous environment between oxygen and an inert gas atmosphere. We found that the deionization of negatively charged particles by oxygen depends on both the excitation power and the shell thickness of the QDs. For QDs with thin shells, which exhibit strong photoluminescence blinking, we observed that the presence of oxygen affects both band-edge carrier blinking and hot-carrier blinking.

2.
J Chem Phys ; 156(6): 061102, 2022 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-35168352

RESUMO

Mobile charge carriers in heterostructured nanoparticles are relevant for applications requiring charge separation and extraction. We investigate the benchmark systems CdSe-CdS core-shell quantum dots and quantum dots in quantum rods by optical and THz pump-probe spectroscopy. We relate photoconductivity and carrier location and observe that only shell-located electrons in quantum rods contribute to an observable photoconductivity. Despite the shallow electron confinement in the quasi-type II heterostructures, core-located carriers are bound into immobile excitons that respond on external electrical fields by polarization.

3.
PLoS One ; 13(8): e0203395, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30169526

RESUMO

IL-6 is required for the response of mice against Listeria monocytogenes. Control of infection depends on classical IL-6 signaling via membrane IL-6Rα, but IL-6 target cells and protective mechanisms remain unclear. We used mice with IL-6Rα-deficiency in T cells (Il6rafl/fl×CD4cre) or myeloid cells (Il6rafl/fl×LysMcre) to define the role of these cells in IL-6-mediated protection. Abrogation of IL-6Rα in T cells did not interfere with bacteria control and induction of TH1 and CD8+ T-cell responses. IL-6Rα-deficiency in myeloid cells caused significant defects in listeria control. This defect was not associated with reduced recruitment of granulocytes and inflammatory monocytes, and both cell populations were activated and not impaired in cytokine production. However, IL-6Rα-deficient inflammatory monocytes displayed diminished expression of IL-4Rα and of CD38, a protein required for phagocytosis and innate control of listeria. In vitro studies revealed that IL-4 and IL-6 cooperated in induction of CD38. In listeria-infected mice, phagocytic activity of inflammatory monocytes correlated with CD38 expression levels on cells and inflammatory monocytes of Il6rafl/fl×LysMcre mice were significantly impaired in phagocytosis. In conclusion, we demonstrate that inhibition of classical IL-6 signaling in myeloid cells causes alterations in differentiation and function of these cells, which subsequently prevent effective control of L. monocytogenes.


Assuntos
Interleucina-6/metabolismo , Listeria monocytogenes/imunologia , Listeriose/imunologia , Listeriose/metabolismo , Células Mieloides/imunologia , Transdução de Sinais/imunologia , ADP-Ribosil Ciclase 1/metabolismo , Animais , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Linfócitos T CD8-Positivos/microbiologia , Inflamação/imunologia , Inflamação/metabolismo , Inflamação/microbiologia , Camundongos , Camundongos Endogâmicos C57BL , Monócitos/imunologia , Monócitos/metabolismo , Monócitos/microbiologia , Células Mieloides/metabolismo , Células Mieloides/microbiologia , Fagocitose/imunologia , Receptores de Interleucina-4/metabolismo , Receptores de Interleucina-6/metabolismo
4.
J Am Soc Nephrol ; 29(4): 1210-1222, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29483158

RESUMO

The IL-17 cytokine family and the cognate receptors thereof have a unique role in organ-specific autoimmunity. Most studies have focused on the founding member of the IL-17 family, IL-17A, as the central mediator of diseases. Indeed, although pathogenic functions have been ascribed to IL-17A and IL-17F in the context of immune-mediated glomerular diseases, the specific functions of the other IL-17 family members in immunity and inflammatory kidney diseases is largely unknown. Here, we report that compared with healthy controls, patients with acute Anti-neutrophil cytoplasmatic antibody (ANCA)-associated crescentic glomerulonephritis (GN) had significantly elevated serum levels of IL-17C (but not IL-17A, F, or E). In mouse models of crescentic GN (nephrotoxic nephritis) and pristane-induced lupus nephritis, deficiency in IL-17C significantly ameliorated the course of GN in terms of renal tissue injury and kidney function. Deficiency of the unique IL-17C receptor IL-17 receptor E (IL-17RE) provided similar protection against crescentic GN. These protective effects associated with a reduced TH17 response. Bone marrow transplantation experiments revealed that IL-17C is produced by tissue-resident cells, but not by lymphocytes. Finally, IL-17RE was highly expressed by CD4+ TH17 cells, and loss of this expression prevented the TH17 responses and subsequent tissue injury in crescentic GN. Our findings indicate that IL-17C promotes TH17 cell responses and immune-mediated kidney disease via IL-17RE expressed on CD4+ TH17 cells. Targeting the IL-17C/IL-17RE pathway may present an intriguing therapeutic strategy for TH17-induced autoimmune disorders.


Assuntos
Doenças Autoimunes/imunologia , Linfócitos T CD4-Positivos/imunologia , Glomerulonefrite/imunologia , Interleucina-17/sangue , Interleucina-17/fisiologia , Receptores de Interleucina-17/fisiologia , Células Th17/imunologia , Animais , Anticorpos Anticitoplasma de Neutrófilos/imunologia , Doenças Autoimunes/sangue , Doenças Autoimunes/patologia , Doenças Autoimunes/prevenção & controle , Glomerulonefrite/sangue , Glomerulonefrite/patologia , Glomerulonefrite/prevenção & controle , Humanos , Interleucina-17/biossíntese , Interleucina-17/deficiência , Interleucina-17/genética , Rim/imunologia , Rim/patologia , Nefrite Lúpica/induzido quimicamente , Nefrite Lúpica/imunologia , Nefrite Lúpica/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Terapia de Alvo Molecular , RNA Mensageiro/biossíntese , Quimera por Radiação , Receptores de Interleucina-17/biossíntese , Receptores de Interleucina-17/deficiência , Receptores de Interleucina-17/genética , Terpenos/toxicidade , Regulação para Cima
5.
J Am Soc Nephrol ; 28(7): 2068-2080, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28154198

RESUMO

Innate lymphoid cells (ILCs) have an important role in the immune system's response to different forms of infectious and noninfectious pathologies. In particular, IL-5- and IL-13-producing type 2 ILCs (ILC2s) have been implicated in repair mechanisms that restore tissue integrity after injury. However, the presence of renal ILCs in humans has not been reported. In this study, we show that ILC populations are present in the healthy human kidney. A detailed characterization of kidney-residing ILC populations revealed that IL-33 receptor-positive ILC2s are a major ILC subtype in the kidney of humans and mice. Short-term IL-33 treatment in mice led to sustained expansion of IL-33 receptor-positive kidney ILC2s and ameliorated adriamycin-induced glomerulosclerosis. Furthermore, the expansion of ILC2s modulated the inflammatory response in the diseased kidney in favor of an anti-inflammatory milieu with a reduction of pathogenic myeloid cell infiltration and a marked accumulation of eosinophils that was required for tissue protection. In summary, kidney-residing ILC2s can be effectively expanded in the mouse kidney by IL-33 treatment and are central regulators of renal repair mechanisms. The presence of ILC2s in the human kidney tissue identifies these cells as attractive therapeutic targets for CKD in humans.


Assuntos
Interleucina-33/fisiologia , Nefropatias/imunologia , Glomérulos Renais/patologia , Linfócitos/imunologia , Animais , Proliferação de Células , Células Cultivadas , Progressão da Doença , Feminino , Humanos , Imunidade Inata , Interleucina-33/uso terapêutico , Nefropatias/prevenção & controle , Linfócitos/classificação , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Esclerose/imunologia , Esclerose/prevenção & controle
6.
Immunity ; 45(5): 1078-1092, 2016 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-27851911

RESUMO

Th17 cells are most abundant in the gut, where their presence depends on the intestinal microbiota. Here, we examined whether intestinal Th17 cells contribute to extra-intestinal Th17 responses in autoimmune kidney disease. We found high frequencies of Th17 cells in the kidneys of patients with antineutrophil cytoplasmatic antibody (ANCA)-associated glomerulonephritis. We utilized photoconversion of intestinal cells in Kaede mice to track intestinal T cell mobilization upon glomerulonephritis induction, and we found that Th17 cells egress from the gut in a S1P-receptor-1-dependent fashion and subsequently migrate to the kidney via the CCL20/CCR6 axis. Depletion of intestinal Th17 cells in germ-free and antibiotic-treated mice ameliorated renal disease, whereas expansion of these cells upon Citrobacter rodentium infection exacerbated pathology. Thus, in some autoimmune settings, intestinal Th17 cells migrate into target organs, where they contribute to pathology. Targeting the intestinal Th17 cell "reservoir" may present a therapeutic strategy for these autoimmune disorders.


Assuntos
Doenças Autoimunes/imunologia , Quimiotaxia de Leucócito/imunologia , Glomerulonefrite/imunologia , Receptores de Lisoesfingolipídeo/imunologia , Células Th17/imunologia , Animais , Citrobacter rodentium , Modelos Animais de Doenças , Infecções por Enterobacteriaceae/imunologia , Citometria de Fluxo , Humanos , Intestinos/imunologia , Rim/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Reação em Cadeia da Polimerase em Tempo Real , Receptores de Esfingosina-1-Fosfato
7.
J Immunol ; 197(2): 449-57, 2016 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-27271566

RESUMO

The ability of CD4(+) T cells to differentiate into pathogenic Th1 and Th17 or protective T regulatory cells plays a pivotal role in the pathogenesis of autoimmune diseases. Recent data suggest that CD4(+) T cell subsets display a considerable plasticity. This plasticity seems to be a critical factor for their pathogenicity, but also for the potential transition of pathogenic effector T cells toward a more tolerogenic phenotype. The aim of the current study was to analyze the plasticity of Th17 cells in a mouse model of acute crescentic glomerulonephritis and in a mouse chronic model of lupus nephritis. By transferring in vitro generated, highly purified Th17 cells and by using IL-17A fate reporter mice, we demonstrate that Th17 cells fail to acquire substantial expression of the Th1 and Th2 signature cytokines IFN-γ and IL-13, respectively, or the T regulatory transcription factor Foxp3 throughout the course of renal inflammation. In an attempt to therapeutically break the stability of the Th17 phenotype in acute glomerulonephritis, we subjected nephritic mice to CD3-specific Ab treatment. Indeed, this treatment induced an immunoregulatory phenotype in Th17 cells, which was marked by high expression of IL-10 and attenuated renal tissue damage in acute glomerulonephritis. In summary, we show that Th17 cells display a minimum of plasticity in acute and chronic experimental glomerulonephritis and introduce anti-CD3 treatment as a tool to induce a regulatory phenotype in Th17 cells in the kidney that may be therapeutically exploited.


Assuntos
Doenças Autoimunes/imunologia , Diferenciação Celular/imunologia , Glomerulonefrite/imunologia , Nefrite Lúpica/imunologia , Células Th17/imunologia , Animais , Modelos Animais de Doenças , Citometria de Fluxo , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Reação em Cadeia da Polimerase em Tempo Real , Subpopulações de Linfócitos T/imunologia
8.
J Am Soc Nephrol ; 27(12): 3666-3677, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27030744

RESUMO

The TH17 immune response has a central role in the pathogenesis of autoimmune diseases, implicating the TH17 master cytokine, IL-17A, as the critical mediator of diseases such as human and experimental crescentic GN. However, the relative importance of additional TH17 effector cytokines, including IL-17F, in immune-mediated tissue injury remains to be fully elucidated. Here, using a mouse model of acute crescentic GN (nephrotoxic nephritis), we identified CD4+ T cells and γδ T cells as the major cellular source of IL-17F in the inflamed kidney. Interventional studies using IL-17F gene-deficient mice, IL-17F-neutralizing antibodies, and adoptive transfer experiments into Rag1-/- mice demonstrated that CD4+ T cell-derived IL-17F drives renal tissue injury in acute crescentic GN. Notably, IL-17F-deficient nephritic mice had fewer renal infiltrating neutrophils than wild-type nephritic mice, and neutrophil depletion did not affect the course of GN in IL-17F-deficient mice. Moreover, in the chronic model of pristane-induced SLE, IL-17F-deficient mice developed less severe disease than wild-type mice, with respect to survival and renal injury. Finally, we show that IL-17F induced expression of the neutrophil-attracting chemokines CXCL1 and CXCL5 in kidney cells. The finding that IL-17F has a nonredundant function in the development of renal tissue injury in experimental GN might be of great importance for the development of anti-IL-17 cytokine therapies in TH17-mediated human autoimmune diseases.


Assuntos
Doenças Autoimunes/etiologia , Glomerulonefrite/imunologia , Interleucina-17/fisiologia , Animais , Doenças Autoimunes/patologia , Glomerulonefrite/patologia , Masculino , Camundongos , Neutrófilos
9.
J Am Soc Nephrol ; 27(7): 1933-42, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-26534920

RESUMO

Chemokines and chemokine receptors are implicated in regulatory T cell (Treg) trafficking to sites of inflammation and suppression of excessive immune responses in inflammatory and autoimmune diseases; however, the specific requirements for Treg migration into the inflamed organs and the positioning of these cells within the tissue are incompletely understood. Here, we report that Tregs expressing the TH1-associated chemokine receptor CXCR3 are enriched in the kidneys of patients with ANCA-associated crescentic GN and colocalize with CXCR3(+) effector T cells. To investigate the functional role of CXCR3(+) Tregs, we generated mice that lack CXCR3 in Tregs specifically (Foxp3(eGFP-Cre) × Cxcr3(fl/fl)) and induced experimental crescentic GN. Treg-specific deletion of CXCR3 resulted in reduced Treg recruitment to the kidney and an overwhelming TH1 immune response, with an aggravated course of the nephritis that was reversible on anti-IFNγ treatment. Together, these findings show that a subset of Tregs expresses CXCR3 and thereby, acquires trafficking properties of pathogenic CXCR3(+) TH1 cells, allowing Treg localization and control of excessive TH1 responses at sites of inflammation.


Assuntos
Glomerulonefrite/imunologia , Receptores CXCR3 , Linfócitos T Reguladores/imunologia , Células Th1/imunologia , Animais , Glomerulonefrite/patologia , Masculino , Camundongos
10.
J Am Soc Nephrol ; 26(9): 2105-17, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25762060

RESUMO

ANCA-associated vasculitis is the most frequent cause of crescentic GN. To define new molecular and/or cellular biomarkers of this disease in the kidney, we performed microarray analyses of renal biopsy samples from patients with ANCA-associated crescentic GN. Expression profiles were correlated with clinical data in a prospective study of patients with renal ANCA disease. CC chemokine ligand 18 (CCL18), acting through CC chemokine receptor 8 (CCR8) on mononuclear cells, was identified as the most upregulated chemotactic cytokine in patients with newly diagnosed ANCA-associated crescentic GN. Macrophages and myeloid dendritic cells in the kidney were detected as CCL18-producing cells. The density of CCL18(+) cells correlated with crescent formation, interstitial inflammation, and impairment of renal function. CCL18 protein levels were higher in sera of patients with renal ANCA disease compared with those in sera of patients with other forms of crescentic GN. CCL18 serum levels were higher in patients who suffered from ANCA-associated renal relapses compared with those in patients who remained in remission. Using a murine model of crescentic GN, we explored the effects of the CCL18 murine functional analog CCL8 and its receptor CCR8 on kidney function and morphology. Compared with wild-type mice, Ccr8(-/-) mice had significantly less infiltration of pathogenic mononuclear phagocytes. Furthermore, Ccr8(-/-) mice maintained renal function better and had reduced renal tissue injury. In summary, our data indicate that CCL18 drives renal inflammation through CCR8-expressing cells and could serve as a biomarker for disease activity and renal relapse in ANCA-associated crescentic GN.


Assuntos
Vasculite Associada a Anticorpo Anticitoplasma de Neutrófilos/complicações , Quimiocinas CC/sangue , Glomerulonefrite/etiologia , Glomerulonefrite/metabolismo , Idoso , Animais , Biomarcadores/sangue , Quimiocina CCL8/genética , Quimiocina CCL8/metabolismo , Quimiocinas CC/análise , Células Dendríticas/química , Feminino , Glomerulonefrite/patologia , Glomerulonefrite/fisiopatologia , Humanos , Macrófagos/química , Masculino , Camundongos , Pessoa de Meia-Idade , Estudos Prospectivos , Análise Serial de Proteínas , Receptores CCR8/genética , Receptores CCR8/metabolismo , Regulação para Cima
11.
PLoS One ; 8(8): e72321, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23951310

RESUMO

CCL18 has been reported to be present constitutively at high levels in the circulation, and is further elevated during inflammatory diseases. Since it is a rather poor chemoattractant, we wondered if it may have a regulatory role. CCL18 has been reported to inhibit cellular recruitment mediated by CCR3, and we have shown that whilst it is a competitive functional antagonist as assessed by Schild plot analysis, it only binds to a subset of CCR3 receptor populations. We have extended this inhibitory activity to other receptors and have shown that CCL18 is able to inhibit CCR1, CCR2, CCR4 and CCR5 mediated chemotaxis, but has no effect on CCR7 and CCR9, nor the CXC receptors that we have tested. Whilst CCL18 is able to bind to CCR3, it does not bind to the other receptors that it inhibits. We therefore tested the hypothesis that it may displace glycosaminoglycan (GAG) chemokines bound either in cis- on the leukocyte, or in trans-presentation on the endothelial surface, thereby inhibiting the recruitment of leukocytes into the site of inflammation. We show that CCL18 selectivity displaces heparin bound chemokines, and that chemokines from all four chemokine sub-classes displace cell bound CCL18. We propose that CCL18 has regulatory properties inhibiting chemokine function when GAG-mediated presentation plays a role in receptor activation.


Assuntos
Quimiocinas CC/metabolismo , Glicosaminoglicanos/metabolismo , Receptores de Superfície Celular/metabolismo , Motivos de Aminoácidos , Sequência de Aminoácidos , Ligação Competitiva , Carbocianinas/química , Carbocianinas/metabolismo , Células Cultivadas , Quimiocinas/metabolismo , Quimiocinas CC/química , Quimiocinas CC/farmacologia , Quimiotaxia de Leucócito/efeitos dos fármacos , Quimiotaxia de Leucócito/imunologia , Humanos , Cinética , Ligação Proteica/efeitos dos fármacos , Receptores CCR/antagonistas & inibidores , Receptores CCR/metabolismo , Receptores CCR3/antagonistas & inibidores , Receptores CCR3/metabolismo , Transdução de Sinais/efeitos dos fármacos
12.
FEBS J ; 280(19): 4876-87, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23910450

RESUMO

Rhipicephalus sanguineus, the common brown dog tick, produces several chemokine-binding proteins which are secreted into the host in its saliva to modulate the host response during feeding. Two of these demonstrate very restricted selectivity profiles. Here, we describe the characterization of the third, which we named Evasin-4. Evasin-4 was difficult to produce recombinantly using its native signal peptide in HEK cells, but expressed very well using the urokinase-type plasminogen activator signal peptide. Using SPR, Evasin-4 was shown to bind most CC chemokines. Investigation of the neutralization properties by inhibition of chemokine-induced chemotaxis showed that binding and neutralization did not correlate in all cases. Two major anomalies were observed: no binding was observed to CCL2 and CCL13, yet Evasin-4 was able to inhibit chemotaxis induced by these chemokines. Conversely, binding to CCL25 was observed, but Evasin-4 did not inhibit CCL25-induced chemotaxis. Size-exclusion chromatography confirmed that Evasin-4 forms a complex with CCL2 and CCL18. In accordance with the standard properties of unmodified small proteins, Evasin-4 was rapidly cleared following in vivo administration. To enhance the in vivo half-life and optimize its potential as a therapeutic agent, Fc fusions of Evasin-4 were created. Both the N- and C-terminal fusions were shown to retain binding activity, with the C-terminal fusion showing a modest reduction in potency.


Assuntos
Quimiocinas CC/metabolismo , Receptores de Quimiocinas/metabolismo , Animais , Proteínas de Transporte , Linhagem Celular , Quimiocina CCL2/metabolismo , Humanos , Proteínas Quimioatraentes de Monócitos/metabolismo , Ligação Proteica , Carrapatos
13.
Front Immunol ; 4: 193, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23874339

RESUMO

The CC chemokine ligand 18 (CCL18) was first identified as a chemoattractant for naïve T cells. It has been reported to recruit T and B lymphocytes, and we show here, natural killer (NK) cells, but with low efficacy. Investigation of its ability to elicit G-protein-coupled signaling showed that it does not involve extracellular signal-regulated kinase (ERK) phosphorylation, and it is not able to induce receptor internalization, as assessed on CCR3. CCL18 has recently been reported to possess activities unrelated to cellular recruitment, but it had no effect on T lymphocyte proliferation. We postulated that a more potent chemoattractant may be produced under inflammatory conditions but only minor truncations were observed, with the major form being the full-length protein. In view of the lack of potent immunomodulatory properties, we wondered if binding to CCL18 by the tick chemokine binding proteins Evasin-1 and -4 was an artifact of the methods used, but complex formation was confirmed by size exclusion chromatography, and abrogation of its binding to, and antagonism of, CCR3. Its receptor has remained elusive since its cloning in 1997, although it has been reported to induce migration of breast cancer cells by signaling through PITPNM3, but we show that this receptor is not expressed on lymphocytes. We have developed a radiolabeled equilibrium competition binding assay and demonstrated that it bound with high affinity to peripheral blood leukocytes (PBLs), but the binding was displaced similarly by both unlabelled CCL18 as well as heparin. Both heparin binding and binding to PBLs are considerably abrogated by mutation of the BBXB motif in the 40s loop suggesting an essential role of the CCL18-glycosaminoglycan interaction.

14.
Methods Mol Biol ; 1013: 67-92, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23625494

RESUMO

This chapter describes assays that focus on the characterization of compounds identified in high--throughput screening campaigns, and the subsequent medicinal chemistry programs. They cover methods to determine potency in buffer, the effect of whole blood on the compounds' activity and finally the pharmacokinetic (PK)/pharmacodynamic (PD) -relationship of the compounds in a rodent species.


Assuntos
Descoberta de Drogas/métodos , Ensaios de Triagem em Larga Escala , Receptores de Quimiocinas/antagonistas & inibidores , Animais , Automação Laboratorial , Técnicas de Cultura de Células , Ensaios de Migração Celular , Células Cultivadas , Quimiocinas/metabolismo , Quimiotaxia/efeitos dos fármacos , Espectroscopia Dielétrica , Relação Dose-Resposta a Droga , Ensaio de Imunoadsorção Enzimática , Humanos , Ligantes , Farmacocinética , Ligação Proteica , Receptores de Quimiocinas/metabolismo , Transdução de Sinais/efeitos dos fármacos
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