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1.
Eur Arch Otorhinolaryngol ; 280(5): 2373-2385, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36441246

RESUMO

PURPOSE: The aim of the present study was to assess the efficacy of the Ronch®AP palatal device in treating patients with moderate and severe forms of obstructive sleep apnea syndrome. METHODS: In a randomized controlled trial 22 patients were examined with the Ronch®AP palatal device after 4 weeks of usage. Their results were compared to a control group of 30 patients who did not receive any treatment during this time. All patients included did not tolerate CPAP therapy. Among other parameters the apnea-hypopnea index (AHI) was measured using nocturnal cardiorespiratory polysomnography. Daytime sleepiness was assessed using Epworth Sleepiness Scale. Pittsburgh Sleep Quality Index was used to analyze sleep quality. RESULTS: Using the Ronch®AP palatal device AHI was reduced from an average of 35.34 ± 14.9/h to 19.18 ± 14.93/h, whereas the control group only showed a minimal mean reduction from 31.32 ± 12.76/h to 29.37 ± 17.11/h. The difference in reduction between the two randomized groups was highly significant (d = - 14.2, 95% CI 5.9-22.6, t = 3.4, df = 49.9, p = 0.001). Epworth Sleepiness Scale score was lowered from 9.18 ± 4.73 to 7.82 ± 4.14 on average and sleep quality improved by - 1.91 ± 2.31. Both changes were also statistically relevant (p < 0.005). CONCLUSIONS: The Ronch®AP device is an effective alternative treatment option for patients suffering from moderate and severe forms of obstructive sleep apnea syndrome and not tolerating CPAP therapy. TRIAL REGISTRATION NUMBER: 407-16 with approval from the local ethical committee (Ethikkommission der Medizinischen Fakultät der LMU München).


Assuntos
Apneia Obstrutiva do Sono , Sonolência , Humanos , Apneia Obstrutiva do Sono/diagnóstico , Apneia Obstrutiva do Sono/terapia , Polissonografia , Resultado do Tratamento , Palato , Pressão Positiva Contínua nas Vias Aéreas
2.
Int J Mol Sci ; 23(21)2022 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-36362301

RESUMO

The progression of non-muscle-invasive bladder cancer (NMIBC) to muscle-invasive bladder cancer (MIBC) is a major challenge in urologic oncology. However, understanding of the molecular processes remains limited. The dysregulation of IQGAP2 is becoming increasingly evident in most tumor entities, and it plays a role in multiple oncogenic pathways, so we evaluated the role of IQGAP2 in bladder cancer. IQGAP2 was downregulated in tumors compared with normal urothelium tissues and cells. IQGAP2 effectively attenuated bladder cancer cell growth independently from apoptosis. Reduced IQGAP2 promoted EMT in bladder cancer cells via activation of the MAPK/ERK pathway. In addition, IQGAP2 might influence key cellular processes, such as proliferation and metastasis, through the regulation of cytokines. In conclusion, we suggest that IQGAP2 plays a tumor-suppressing role in bladder cancer, possibly via inhibiting the MAPK/ERK pathway and reducing cytokines.


Assuntos
Neoplasias da Bexiga Urinária , Humanos , Linhagem Celular Tumoral , Citocinas/metabolismo , Regulação Neoplásica da Expressão Gênica , Sistema de Sinalização das MAP Quinases , Proteínas Ativadoras de ras GTPase/genética , Proteínas Ativadoras de ras GTPase/metabolismo , Neoplasias da Bexiga Urinária/metabolismo , Urotélio/patologia , Proteínas Quinases Ativadas por Mitógeno/metabolismo
3.
Pharmaceutics ; 14(9)2022 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-36145639

RESUMO

Adrenocortical carcinoma (ACC) is a heterogeneous malignancy related to poor prognosis and limited treatment options. The orphan drug mitotane (MT) is still a cornerstone in ACC therapy, however, its application is characterized by low aqueous solubility, poor bioavailability, and unfavorable pharmacokinetics, often resulting in below-target plasma concentrations or toxic side effects. Throughout the last decades, nanoparticulate formulations have become attractive carriers to improve anticancer therapy. In this study, injectable MT liposomes (DOPC-MT) and albumin-stabilized MT nanoparticles (BSA-MT) were investigated in depth with respect to their physicochemical properties, and their colloidal and therapeutical stability upon storage. Furthermore, in vitro cytotoxicity was evaluated using the ACC model cell line NCI-H295R for preparing multicellular tumor spheroids, and was compared to non-malignant human dermal fibroblasts. Our results clearly demonstrate that BSA-MT, unlike DOPC-MT, represents a stable and storable MT formulation with a high drug concentration in an aqueous medium. Dual centrifugation was established as a reproducible method for nanoparticle preparation. Although an efficient cytotoxic effect on ACC tumor spheroids was demonstrated, concomitant low toxicity to fibroblasts suggests that higher drug concentrations may be tolerated in vivo. Consequently, BSA-MT is a novel and promising therapeutical approach to address key challenges in MT treatment.

4.
Cell Rep ; 39(13): 111019, 2022 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-35767961

RESUMO

Binding of BAFF to BAFFR activates in mature B cells PI3K/AKT signaling regulating protein synthesis, metabolic fitness, and survival. In humans, naive and memory B cells express the same levels of BAFFR, but only memory B cells seem to survive without BAFF. Here, we show that BAFF activates PI3K/AKT only in naive B cells and changes the expression of genes regulating migration, proliferation, growth, and survival. BAFF-induced PI3K/AKT activation requires direct interactions between BAFFR and the B cell antigen receptor (BCR) components CD79A and CD79B and is enhanced by the AKT coactivator TCL1A. Compared to memory B cells, naive B cells express more surface BCRs, which interact better with BAFFR than IgG or IgA, thus allowing stronger responses to BAFF. As ablation of BAFFR in naive and memory B cells causes cell death independent of BAFF-induced signaling, BAFFR seems to act also as an intrinsic factor for B cell survival.


Assuntos
Receptor do Fator Ativador de Células B , Células B de Memória , Fosfatidilinositol 3-Quinases , Proteínas Proto-Oncogênicas c-akt , Receptores de Antígenos de Linfócitos B , Fator Ativador de Células B/imunologia , Fator Ativador de Células B/metabolismo , Receptor do Fator Ativador de Células B/imunologia , Receptor do Fator Ativador de Células B/metabolismo , Humanos , Células B de Memória/imunologia , Células B de Memória/metabolismo , Fosfatidilinositol 3-Quinases/imunologia , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/imunologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptores de Antígenos de Linfócitos B/imunologia , Receptores de Antígenos de Linfócitos B/metabolismo
5.
Eur Arch Otorhinolaryngol ; 279(2): 801-810, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34019148

RESUMO

PURPOSE: For perennial inhalant allergens such as house dust mite (HDM), the German guideline on allergen-specific immunotherapy explicitly recommends provocation testing. This procedure is time-consuming, expensive, and potentially dangerous for the patient. Recently it has been discussed whether provocation tests are really necessary for diagnosing allergy to Dermatophagoides species. Thus, our study aimed to analyze the concordance between nasal provocation tests with Dermatophagoides species and anamnestic data. METHODS: We retrospectively analyzed the concordance between patients' histories including self-reported symptom scores and the results of provocation testing in 471 individuals with proven sensitization to Dermatophagoides species. RESULTS: 248 patients had a positive nasal provocation test (NPT) result to Dermatophagoides species and 223 individuals a negative NPT result. Patients allergic to HSM suffered significantly more often from atopic dermatitis (14% vs. 7%, p = 0.046) and more from asthma (20% vs. 19%, p = 0.851). Moreover, individuals with clinically silent sensitization complained less about nasal secretion (37% vs. 45%, p = 0.244) but significantly more about nasal dryness (46% vs. 34%, p = 0.046) whereas rates of nasal airway obstruction, ocular complaints and sleep quality were comparable in both groups. Allergic patients reported more often perennial (34% vs. 30%, p = 0.374) and location-dependent (39% vs. 31%, p = 0.090) symptoms. However, the discrepant prevalence of atopic dermatitis was the only statistically significant difference between both groups. CONCLUSION: Despite slight differences between both patient groups, clinical data are not sufficient to distinguish between silent sensitization and clinically relevant allergic rhinitis to HDM. Therefore, nasal provocation testing remains the gold standard for assessing clinical relevance in patients sensitized to Dermatophagoides species.


Assuntos
Pyroglyphidae , Rinite Alérgica , Alérgenos , Animais , Antígenos de Dermatophagoides , Poeira , Humanos , Estudos Retrospectivos , Rinite Alérgica/diagnóstico , Rinite Alérgica/epidemiologia , Testes Cutâneos , Qualidade do Sono
6.
Cancers (Basel) ; 13(3)2021 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-33530588

RESUMO

The prognosis of late-stage epithelial ovarian cancer (EOC) patients is affected by chemotherapy response and the malignant potential of the tumor cells. In earlier work, we identified hypermethylation of the runt-related transcription factor 3 gene (RUNX3) as a prognostic biomarker and contrary functions of transcript variants (TV1 and TV2) in A2780 and SKOV3 cells. The aim of the study was to further validate these results and to increase the knowledge about RUNX3 function in EOC. New RUNX3 overexpression models of high-grade serous ovarian cancer (HGSOC) were established and analyzed for phenotypic (IC50 determination, migration, proliferation and angiogenesis assay, DNA damage analysis) and transcriptomic consequences (NGS) of RUNX3 TV1 and TV2 overexpression. Platinum sensitivity was affected by a specific transcript variant depending on BRCA background. RUNX3 TV2 induced an increased sensitivity in BRCA1wt cells (OVCAR3), whereas TV1 increased the sensitivity and induced a G2/M arrest under treatment in BRCA1mut cells (A13-2-12). These different phenotypes relate to differences in DNA repair: homologous recombination deficient A13-2-12 cells show less γH2AX foci despite higher levels of Pt-DNA adducts. RNA-Seq analyses prove transcript variant and cell-line-specific RUNX3 effects. Pathway analyses revealed another clinically important function of RUNX3-regulation of angiogenesis. This was confirmed by thrombospondin1 analyses, HUVEC spheroid sprouting assays and proteomic profiling. Importantly, conditioned media (CM) from RUNX3 TV1 overexpressing A13-2-12 cells induced an increased HUVEC sprouting. Altogether, the presented data support the hypothesis of different functions of RUNX3 transcript variants related to the clinically relevant processes-platinum resistance and angiogenesis.

7.
Cells ; 10(1)2021 01 06.
Artigo em Inglês | MEDLINE | ID: mdl-33418944

RESUMO

Bladder cancer is a very heterogeneous disease and the molecular mechanisms of carcinogenesis and progression are insufficiently investigated. From the DNA sequencing analysis of matched non-muscle-invasive bladder cancer (NMIBC) and muscle-invasive bladder cancer (MIBC) samples from eight patients, we identified the tumour-associated gene SLC35F2 to be mutated in the 5' and 3' untranslated region (UTR). One mutation in 3'UTR increased the luciferase activity reporter, suggesting its influence on the protein expression of SLC35F2. The mRNA level of SLC35F2 was increased in MIBC compared with NMIBC. Furthermore, in immunohistochemical staining, we observed a strong intensity of SLC35F2 in single tumour cells and in the border cells of solid tumour areas with an atypical accumulation around the nucleus, especially in the MIBC. This suggests that SLC35F2 might be highly expressed in aggressive and invasive tumour cells. Moreover, knockdown of SLC35F2 repressed the growth of bladder cancer cells in the monolayer and spheroid model and suppressed migration and invasion of bladder cancer cells. In conclusion, we suggest that SLC35F2 is involved in bladder cancer progression and might provide a new therapeutic approach, for example, by the anti-cancer drug YM155, a cargo of the SLC35F2 transporter.


Assuntos
Movimento Celular , Proteínas de Membrana Transportadoras/genética , Neoplasias da Bexiga Urinária/patologia , Regiões 3' não Traduzidas/genética , Idoso , Linhagem Celular Tumoral , Proliferação de Células , Feminino , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Humanos , Luciferases/metabolismo , Masculino , Proteínas de Membrana Transportadoras/metabolismo , Pessoa de Meia-Idade , Músculos/patologia , Mutação/genética , Invasividade Neoplásica , Oncogenes , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Esferoides Celulares/metabolismo , Esferoides Celulares/patologia , Neoplasias da Bexiga Urinária/genética
8.
Sci Rep ; 9(1): 15932, 2019 11 04.
Artigo em Inglês | MEDLINE | ID: mdl-31685838

RESUMO

In advanced inflammatory disease, microvascular thrombosis leads to the interruption of blood supply and provokes ischemic tissue injury. Recently, intravascularly adherent leukocytes have been reported to shape the blood flow in their immediate vascular environment. Whether these rheological effects are relevant for microvascular thrombogenesis remains elusive. Employing multi-channel in vivo microscopy, analyses in microfluidic devices, and computational modeling, we identified a previously unanticipated role of leukocytes for microvascular clot formation in inflamed tissue. For this purpose, neutrophils adhere at distinct sites in the microvasculature where these immune cells effectively promote thrombosis by shaping the rheological environment for platelet aggregation. In contrast to larger (lower-shear) vessels, this process in high-shear microvessels does not require fibrin generation or extracellular trap formation, but involves GPIbα-vWF and CD40-CD40L-dependent platelet interactions. Conversely, interference with these cellular interactions substantially compromises microvascular clotting. Thus, leukocytes shape the rheological environment in the inflamed venular microvasculature for platelet aggregation thereby effectively promoting the formation of blood clots. Targeting this specific crosstalk between the immune system and the hemostatic system might be instrumental for the prevention and treatment of microvascular thromboembolic pathologies, which are inaccessible to invasive revascularization strategies.


Assuntos
Plaquetas/fisiologia , Neutrófilos/fisiologia , Agregação Plaquetária/fisiologia , Trombose/patologia , Animais , Plaquetas/metabolismo , Antígenos CD40/deficiência , Antígenos CD40/genética , Ligante de CD40/deficiência , Ligante de CD40/genética , Lipopolissacarídeos/toxicidade , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microfluídica/instrumentação , Microfluídica/métodos , Microscopia de Fluorescência , Microvasos/efeitos dos fármacos , Microvasos/patologia , Neutrófilos/imunologia , Adesividade Plaquetária/efeitos dos fármacos , Complexo Glicoproteico GPIb-IX de Plaquetas/metabolismo , Reologia , Trombose/metabolismo , Fator de von Willebrand/metabolismo
9.
J Exp Med ; 216(1): 152-175, 2019 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-30530755

RESUMO

Organism aging is characterized by increased inflammation and decreased stem cell function, yet the relationship between these factors remains incompletely understood. This study shows that aged hematopoietic stem and progenitor cells (HSPCs) exhibit increased ground-stage NF-κB activity, which enhances their responsiveness to undergo differentiation and loss of self-renewal in response to inflammation. The study identifies Rad21/cohesin as a critical mediator of NF-κB signaling, which increases chromatin accessibility in the vicinity of NF-κB target genes in response to inflammation. Rad21 is required for normal differentiation, but limits self-renewal of hematopoietic stem cells (HSCs) during aging and inflammation in an NF-κB-dependent manner. HSCs from aged mice fail to down-regulate Rad21/cohesin and inflammation/differentiation signals in the resolution phase of inflammation. Inhibition of cohesin/NF-κB reverts hypersensitivity of aged HSPCs to inflammation-induced differentiation and myeloid-biased HSCs with disrupted/reduced expression of Rad21/cohesin are increasingly selected during aging. Together, Rad21/cohesin-mediated NF-κB signaling limits HSPC function during aging and selects for cohesin-deficient HSCs with myeloid-skewed differentiation.


Assuntos
Envelhecimento/imunologia , Proteínas de Ciclo Celular/imunologia , Proliferação de Células , Proteínas Cromossômicas não Histona/imunologia , Células-Tronco Hematopoéticas/imunologia , NF-kappa B/imunologia , Transdução de Sinais/imunologia , Envelhecimento/genética , Animais , Proteínas de Ciclo Celular/genética , Proteínas Cromossômicas não Histona/genética , Proteínas de Ligação a DNA , Inflamação/genética , Inflamação/imunologia , Camundongos , Camundongos Knockout , NF-kappa B/genética , Proteínas Nucleares/genética , Proteínas Nucleares/imunologia , Fosfoproteínas/genética , Fosfoproteínas/imunologia , Transdução de Sinais/genética , Coesinas
10.
Arterioscler Thromb Vasc Biol ; 38(4): 829-842, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29371242

RESUMO

OBJECTIVE: Ischemia-reperfusion (I/R) injury significantly contributes to organ dysfunction and failure after myocardial infarction, stroke, and transplantation. In addition to its established role in the fibrinolytic system, plasminogen activator inhibitor-1 has recently been implicated in the pathogenesis of I/R injury. The underlying mechanisms remain largely obscure. APPROACH AND RESULTS: Using different in vivo microscopy techniques as well as ex vivo analyses and in vitro assays, we identified that plasminogen activator inhibitor-1 rapidly accumulates on microvascular endothelial cells on I/R enabling this protease inhibitor to exhibit previously unrecognized functional properties by inducing an increase in the affinity of ß2 integrins in intravascularly rolling neutrophils. These events are mediated through low-density lipoprotein receptor-related protein-1 and mitogen-activated protein kinase-dependent signaling pathways that initiate intravascular adherence of these immune cells to the microvascular endothelium. Subsequent to this process, extravasating neutrophils disrupt endothelial junctions and promote the postischemic microvascular leakage. Conversely, deficiency of plasminogen activator inhibitor-1 effectively reversed leukocyte infiltration, microvascular dysfunction, and tissue injury on experimental I/R without exhibiting side effects on microvascular hemostasis. CONCLUSIONS: Our experimental data provide novel insights into the nonfibrinolytic properties of the fibrinolytic system and emphasize plasminogen activator inhibitor-1 as a promising target for the prevention and treatment of I/R injury.


Assuntos
Músculos Abdominais/irrigação sanguínea , Fígado/irrigação sanguínea , Microvasos/metabolismo , Infiltração de Neutrófilos , Neutrófilos/metabolismo , Inibidor 1 de Ativador de Plasminogênio/metabolismo , Traumatismo por Reperfusão/metabolismo , Músculos Abdominais/metabolismo , Músculos Abdominais/patologia , Animais , Antígenos CD18/metabolismo , Permeabilidade Capilar , Linhagem Celular , Modelos Animais de Doenças , Humanos , Cinética , Migração e Rolagem de Leucócitos , Fígado/metabolismo , Fígado/patologia , Proteína-1 Relacionada a Receptor de Lipoproteína de Baixa Densidade , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microvasos/patologia , Ativação de Neutrófilo , Neutrófilos/transplante , Inibidor 1 de Ativador de Plasminogênio/deficiência , Inibidor 1 de Ativador de Plasminogênio/genética , Conformação Proteica , Receptores de LDL/metabolismo , Traumatismo por Reperfusão/patologia , Transdução de Sinais , Proteínas Supressoras de Tumor/metabolismo
11.
Br J Neurosurg ; 31(3): 379-381, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26761416

RESUMO

We report the first case of an intracranial and intradural nasal polyposis occurring in a close topographical relation to a previous, iatrogenic anterior skull base defect. The tumour was resected and the skull base defect was closed transnasally by an interdisciplinary team. The histopathological report confirmed recurrent polyposis.


Assuntos
Pólipos Nasais/cirurgia , Neoplasias Nasofaríngeas/cirurgia , Neuroendoscopia/métodos , Neoplasias da Base do Crânio/cirurgia , Idoso , Feminino , Humanos , Doença Iatrogênica , Imageamento por Ressonância Magnética , Recidiva Local de Neoplasia/cirurgia , Base do Crânio/cirurgia
12.
Sci Rep ; 6: 34589, 2016 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-27713552

RESUMO

The unprecedented outbreak of Ebola in West Africa resulted in over 28,000 cases and 11,000 deaths, underlining the need for a better understanding of the biology of this highly pathogenic virus to develop specific counter strategies. Two filoviruses, the Ebola and Marburg viruses, result in a severe and often fatal infection in humans. However, bats are natural hosts and survive filovirus infections without obvious symptoms. The molecular basis of this striking difference in the response to filovirus infections is not well understood. We report a systematic overview of differentially expressed genes, activity motifs and pathways in human and bat cells infected with the Ebola and Marburg viruses, and we demonstrate that the replication of filoviruses is more rapid in human cells than in bat cells. We also found that the most strongly regulated genes upon filovirus infection are chemokine ligands and transcription factors. We observed a strong induction of the JAK/STAT pathway, of several genes encoding inhibitors of MAP kinases (DUSP genes) and of PPP1R15A, which is involved in ER stress-induced cell death. We used comparative transcriptomics to provide a data resource that can be used to identify cellular responses that might allow bats to survive filovirus infections.


Assuntos
Ebolavirus/metabolismo , Regulação da Expressão Gênica , Doença pelo Vírus Ebola/metabolismo , Doença do Vírus de Marburg/metabolismo , Marburgvirus/metabolismo , Transdução de Sinais , Transcrição Gênica , Animais , Linhagem Celular Tumoral , Quirópteros , Humanos
13.
J Appl Toxicol ; 34(11): 1167-76, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24531921

RESUMO

Although carbon-based nanomaterials (CBNs) have been shown to exert prothrombotic effects in microvessels, it is poorly understood whether CBNs also have the potential to interfere with the process of leukocyte-endothelial cell interactions and whether the shape of CBNs plays a role in these processes. Thus, the aim of this study was to compare the acute effects of two differently shaped CBNs, fiber-shaped single-walled carbon nanotubes (SWCNT) and spherical ultrafine carbon black (CB), on thrombus formation as well as on leukocyte-endothelial cell interactions and leukocyte transmigration in the murine microcirculation upon systemic administration in vivo. Systemic administration of both SWCNT and CB accelerated arteriolar thrombus formation at a dose of 1 mg kg(-1) body weight, whereas SWCNT exerted a prothrombotic effect also at a lower dose (0.1 mg kg(-1) body weight). In vitro, both CBNs induced P-selectin expression on human platelets and formation of platelet-granulocyte complexes. In contrast, injection of fiber-shaped SWCNT or of spherical CB did not induce leukocyte-endothelial cell interactions or leukocyte transmigration. In vitro, both CBNs slightly increased the expression of activation markers on human monocytes and granulocytes. These findings suggest that systemic administration of CBNs accelerates arteriolar thrombus formation independently of the CBNs' shape, but does not induce leukocyte-endothelial cell interactions or leukocyte transmigration.


Assuntos
Microcirculação/efeitos dos fármacos , Nanotubos de Carbono/toxicidade , Fuligem/toxicidade , Animais , Arteríolas/efeitos dos fármacos , Arteríolas/patologia , Plaquetas/efeitos dos fármacos , Plaquetas/metabolismo , Células Endoteliais/citologia , Células Endoteliais/efeitos dos fármacos , Humanos , Leucócitos/citologia , Leucócitos/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microscopia Eletrônica de Varredura , Selectina-P/genética , Selectina-P/metabolismo , Trombose/induzido quimicamente
14.
J Biol Chem ; 287(51): 42664-74, 2012 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-23091059

RESUMO

The T-cell antigen receptor (TCR) exists in monomeric and nanoclustered forms independently of antigen binding. Although the clustering is involved in the regulation of T-cell sensitivity, it is unknown how the TCR nanoclusters form. We show that cholesterol is required for TCR nanoclustering in T cells and that this clustering enhances the avidity but not the affinity of the TCR-antigen interaction. Investigating the mechanism of the nanoclustering, we found that radioactive photocholesterol specifically binds to the TCRß chain in vivo. In order to reduce the complexity of cellular membranes, we used a synthetic biology approach and reconstituted the TCR in liposomes of defined lipid composition. Both cholesterol and sphingomyelin were required for the formation of TCR dimers in phosphatidylcholine-containing large unilamellar vesicles. Further, the TCR was localized in the liquid disordered phase in giant unilamellar vesicles. We propose a model in which cholesterol and sphingomyelin binding to the TCRß chain causes TCR dimerization. The lipid-induced TCR nanoclustering enhances the avidity to antigen and thus might be involved in enhanced sensitivity of memory compared with naive T cells. Our work contributes to the understanding of the function of specific nonannular lipid-membrane protein interactions.


Assuntos
Colesterol/metabolismo , Nanopartículas/química , Receptores de Antígenos de Linfócitos T alfa-beta/metabolismo , Receptores de Antígenos de Linfócitos T/metabolismo , Esfingomielinas/metabolismo , Animais , Membrana Celular/metabolismo , Sobrevivência Celular , Análise por Conglomerados , Reagentes de Ligações Cruzadas/metabolismo , Antígenos de Histocompatibilidade/metabolismo , Humanos , Ligantes , Camundongos , Peptídeos/metabolismo , Fosfatidilcolinas/metabolismo , Ligação Proteica , Multimerização Proteica , Subunidades Proteicas/metabolismo , Receptores de Antígenos de Linfócitos B/metabolismo , Receptores da Transferrina , Lipossomas Unilamelares/metabolismo
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