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1.
Int J Biol Macromol ; 263(Pt 1): 130073, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38342268

RESUMO

Chronic wounds suffer from impaired healing due to microbial attack and poor vascular growth. Thermoresponsive hydrogels gained attention in wound dressing owing to their gelation at physiological temperature enabling them to take the shape of asymmetric wounds. The present study delineates the development of thermoresponsive hydrogel (MCK), from hair-derived keratin (K) and methylcellulose (MC) in the presence of sodium sulfate. The gelation temperature (Tg) of this hydrogel is in the range of 30 °C to 33 °C. Protein-polymer interaction leading to thermoreversible sol-gel transition involved in MCK blends has been analyzed and confirmed by FTIR, XRD, and thermal studies. Keratin, has introduced antioxidant properties to the hydrogel imparted cytocompatibility towards human dermal fibroblasts (HDFs) as evidenced by both MTT and live dead assays. In vitro wound healing assessment has been shown by enhanced migration of HDFs in the presence of MCK hydrogel compared to the control. Also, CAM assay and CD31 expression by the Wistar rat model has shown increased blood vessel branching after the implantation of MCK hydrogel. Further, in vivo study, demonstrated MCK efficacy of hydrogel in accelerating full-thickness wounds with minimal scarring in Wistar rats, re-epithelialization, and reinstatement of the epidermal-dermal junction thereby exhibiting clinical relevance for chronic wounds.


Assuntos
Queratinas , Reepitelização , Ratos , Animais , Humanos , Queratinas/farmacologia , Hidrogéis/farmacologia , Metilcelulose , Ratos Wistar , Cicatrização
2.
Mol Immunol ; 166: 39-49, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38219401

RESUMO

Butyrophilin-like 2 (BTNL2) is a T cell inhibitory molecule that interacts with unknown binding partners to modulate the immune response in a number of inflammatory and autoimmune diseases. In this study, we found that the inhibitory effects of BTNL2 on T cell activation and effector functions can be executed by its N-terminal IgV domain (BTNL2 IgV1) alone. Structure-guided mutation of key residues on BTNL2 IgV1 based on known receptor-ligand interfaces involving immunoglobulin superfamily members revealed that BTNL2 uses a non-canonical binding interface with its putative receptor. A high avidity BTNL2 IgV1 probe revealed that in an inducible model of ulcerative colitis, severe colitis was accompanied by a selective enrichment of BTNL2-receptor expressing effector-memory CD4+ and CD8+ T cells in the Peyer's patches. Intraperitoneal administration of BTNL2 IgV1 resulted in a significant delay in the progression of DSS-induced colitis and also showed reduced activation of the BTNL2-receptor-expressing T cells in the Peyer's patches. Thus, this study demonstrates that the BTNL2-receptor-expressing T cells in the Peyer's patches participate in the disease pathogenesis and can serve as a novel therapeutic target in ulcerative colitis, which can be modulated by BTNL2 IgV1.


Assuntos
Colite Ulcerativa , Colite , Butirofilinas/metabolismo , Linfócitos T CD8-Positivos , Colite Ulcerativa/induzido quimicamente , Nódulos Linfáticos Agregados/metabolismo , Animais
3.
Biosens Bioelectron ; 242: 115733, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-37820555

RESUMO

A soluble isoform of cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) has been found in the serum of healthy individuals and alterations in its expression level have been linked with the development and progression of various cancers. Conventionally, soluble CTLA-4 (sCTLA-4) has been quantified by techniques such as ELISA, western blot, and flow cytometry, which however are time-consuming, highly expensive and require large sample volumes. Therefore, rapid, cost-effective and real-time monitoring of soluble CTLA-4 levels is much needed to facilitate timely diagnosis of a worsening disease and help patient selection for immunotherapeutic interventions in cancer. Here, for the first time, we report an ultrasensitive, highly selective electrochemical nanobody (NAb) based biosensor for the quantitative detection of soluble CTLA-4 employing poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and gold nanoparticles modified electrode with attomole sensitivity. Incorporating nanomaterials with conductive polymers enhances the sensitivity of the electrochemical biosensor, while the nanobody's stability, specificity and ease of production make it a suitable choice as a bioreceptor. The proposed NAb-based sensor can detect sCTLA-4 from pure recombinant protein in a wide concentration range of 100 ag mL-1- 500 µg mL-1, with a limit of detection of 1.19 ag mL-1 (+3σ of the blank signal). The sensor's relative standard deviation for reproducibility is less than 0.4% and has effective real sample analytics for cell culture supernatant with no significant difference with pure recombinant protein (p < 0.05). Our proposed nanobody based sensor exhibits stability for up to 2 weeks (<3% variation). Moreover, this nanobody-based sensor presents a future opportunity for quantitative, ultrasensitive, and economical biosensor development that can be adapted to monitor the immune landscape of cancer patients to provide a larger therapeutic window.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Neoplasias , Humanos , Antígeno CTLA-4 , Ouro , Reprodutibilidade dos Testes , Técnicas Biossensoriais/métodos , Neoplasias/diagnóstico , Proteínas Recombinantes , Técnicas Eletroquímicas/métodos , Limite de Detecção
4.
Appl Microbiol Biotechnol ; 107(21): 6553-6571, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37688595

RESUMO

The Big Grain1 (BG1) gene of rice (Oryza sativa L.) is reported to increase the yield of rice crops; however, its molecular mechanism is largely concealed. To explore its functional prospects, we have taken a structure-function-based approach. In silico analyses suggest OsBG1 is a DNA- and phytohormone-binding protein. Heterologous expression of OsBG1 with galactose-inducible promoter GAL1p in the rhizospheric yeast Candida tropicalis SY005 revealed 7.9- and 1.5-fold higher expression of the gene at 12 and 24 h, respectively, compared to the expression at 36 h post-galactose induction. Functional activity of the induced OsBG1 in engineered yeast increased cell density, specific growth rate, and biomass by 28.5%, 29.8%, and 14.1%, respectively, and decreased the generation time by 21.25%. Flow cytometry-based cell cycle analysis of OsBG1-expressing yeast cells exhibited an increase in the cells of the G2/M population by 15.8% after 12 h of post-galactose induction. The gene expression study of yeast transformants disclosed that OsBG1 regulates cell division by upregulating the expression of the endogenous gene cyclin B1 (CtCYB1) by 1.3- and 1.9-folds at 10 and 12 h, respectively, compared to the control, and is positively influenced by the phytohormone indole acetic acid (IAA). Further, the study revealed that OsBG1 significantly increases biofilm formation, stress tolerance, and IAA production in C. tropicalis SY005, implying its prospective role in enhancing plant growth-promoting traits in microbes. OsBG1-expressing rhizospheric yeast cells significantly improved the germination and growth parameters of the bio-inoculated rice seeds. Altogether, this study suggests OsBG1 can be employed to genetically improve suitable bio-inoculants for their plant growth-promoting traits to augment crop productivity. KEY POINTS: • In silico analyses suggested OsBG1 is a phytohormone-binding transcription factor. • OsBG1 enhanced growth in rhizospheric Candida tropicalis by upregulating CtCYB1. • OsBG1 improved plant growth-promoting traits of the rhizospheric yeast C. tropicalis.


Assuntos
Oryza , Reguladores de Crescimento de Plantas , Reguladores de Crescimento de Plantas/metabolismo , Candida tropicalis/genética , Candida tropicalis/metabolismo , Biomassa , Galactose/metabolismo , Leveduras/metabolismo
5.
Eur J Immunol ; 53(12): e2350528, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37698527

RESUMO

Immunotherapeutic modulation of antigen-specific T-cell responses instead of the whole repertoire helps avoid immune-related adverse events. We have developed an artificial antigen-presenting system (aAPS) where multiple copies of a multimeric peptide-MHC class I complex presenting a murine class I MHC restricted ovalbumin-derived peptide (signal 1), along with a costimulatory ligand (signal 2) are chemically conjugated to a dextran backbone. Cognate naive CD8+ T cells, when treated with this aAPS underwent significant expansion and showed an activated phenotype. Furthermore, elevated expression of effector cytokines led to the differentiation of these cells to cytotoxic T lymphocytes which resulted in target cell lysis, indicative of the functional efficacy of the aAPS. CD8+ T cells with decreased proliferative potential due to repeated antigenic stimulation could also be re-expanded by the developed aAPS. Thus, the developed aAPS warrants further engineering for future application as a rapidly customizable personalized immunotherapeutic agent, incorporating patient-specific MHC-restricted tumor antigens and different costimulatory signals to modulate both naive and antigen-experienced but exhausted tumor-specific T cells in cancer.


Assuntos
Linfócitos T CD8-Positivos , Neoplasias , Humanos , Camundongos , Animais , Dextranos/metabolismo , Ativação Linfocitária , Imunoterapia , Peptídeos/metabolismo , Células Apresentadoras de Antígenos , Neoplasias/terapia , Neoplasias/metabolismo
6.
J Biomater Appl ; 37(9): 1509-1528, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-37069479

RESUMO

Chronic wounds are the outcome of an imbalanced inflammatory response caused by sustenance of immune microenvironment. In this context, tissue engineered graft played great role in healing wounds but faced difficulty in scar remodelling, immune rejection and poor vascularization. All the limitations faced are somewhere linked with the immune cells involved in healing. In this consideration, immunomodulatory biomaterials bridge a large gap with the delivery of modulating factors for triggering key inflammatory cells responsible towards interplay in the wound micro-environment. Inherent physico-chemical properties of biomaterials substantially determine the nature of cell-materials interaction thereby facilitating differential cytokine gradient involved in activation or suppression of inflammatory signalling pathways, and followed by surface marker expression. This review aims to systematically describe the interplay of immune cells involved in different phases in the wound microenvironment and biomaterials. Additionally, it also focuses on modulating innate immune cell responses in the context of triggering the halted phase of the wound healing, i.e., inflammatory phase. The various strategies are highlighted for modulation of wound microenvironment towards wound regeneration including stem cells, cytokines, growth factors, vitamins, and anti-inflammatory agents to induce interactive ability of biomaterials with immune cells. The last section focuses on prospective approaches and current potential strategies for wound regeneration. This includes the development of different models to bridge the gap between mouse models and human patients. Emerging new tools to study inflammatory response owing to biomaterials and novel strategies for modulation of monocyte and macrophage behaviour in the wound environment are also discussed.


Assuntos
Materiais Biocompatíveis , Interação Gene-Ambiente , Animais , Camundongos , Humanos , Materiais Biocompatíveis/metabolismo , Macrófagos/metabolismo , Cicatrização , Citocinas/metabolismo , Imunomodulação
7.
HLA ; 102(1): 66-68, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-36811603

RESUMO

HLA-A*02:01:01:241 differs from HLA-A*02:01:01:01 by a single nucleotide substitution at position 178 in intron 1.


Assuntos
Genômica , Antígenos HLA-A , Humanos , Alelos , Análise de Sequência de DNA , Antígenos HLA-A/genética , Sequenciamento de Nucleotídeos em Larga Escala
8.
J Mater Chem B ; 10(46): 9682-9698, 2022 11 30.
Artigo em Inglês | MEDLINE | ID: mdl-36382583

RESUMO

Endometriosis is a debilitating gynecological disorder in women of reproductive age. Laparoscopy, a minimally invasive surgical procedure, provides a definitive diagnosis of the disease. Current treatments, including hormonal therapy and pain medication, are often associated with undesirable side effects limiting their long-term usage. This calls for exploring newer diagnostic and therapeutic options with minimal side effects. Curcumin is an established anti-endometriotic agent with inherent fluorescent properties; however, poor bioavailability limits its clinical utility. To address this shortcoming, various transition metals were conjugated with curcumin to improve its stability, specificity and pharmacological properties. The chemical stability, hemocompatibility and ability of the synthesized metallo-curcumin complexes (MCCs) to ameliorate endometriotic lesions were investigated. While all of the MCCs exhibited low hemolytic activity, their chemical and biological activities were largely dependent on the nature of the metal ion conjugated to the curcumin molecule. Copper-curcumin and nickel-curcumin complexes demonstrated superior therapeutic efficacy evidenced by enhanced antioxidant activity, selective cytotoxicity and increased accumulation in endometriotic cells mediated by an energy-dependent active transport process.


Assuntos
Curcumina , Endometriose , Feminino , Humanos , Curcumina/química , Endometriose/tratamento farmacológico , Endometriose/patologia , Antioxidantes/química , Cobre/uso terapêutico , Metais/química
9.
Arch Biochem Biophys ; 727: 109329, 2022 09 30.
Artigo em Inglês | MEDLINE | ID: mdl-35738425

RESUMO

Cadherins are a family of cell surface glycoproteins that mediate Ca2+-dependent cell to cell adhesion. They organize to form large macromolecular assemblies at the junctions of cells in order to form and maintain the integrity of tissue structures, thereby playing an indispensable role in the multicellular organization. Notably, a large body of research on E- and N-cadherin, the two most widely studied members of the cadherin superfamily, suggest for homophilic associations among them to drive cell adhesion. Interestingly, latest studies also highlight for direct crosstalk among these two classical cadherins to form heterotypic connections in physiological as well as in disease environment. However, the molecular details for the heterophilic association of E-cadherin and N-cadherin has not been investigated yet, which we aimed to address in this work. Using surface plasmon resonance and flow cytometry based biophysical studies we observed heterophilic interaction between E- and N-cadherin mediated through the membrane distal ectodomains. Further, the heterodimeric interface of E-cadherin and N-cadherin was mapped using structure-guided mutational studies followed by complementary biophysical analyses to identify the important interface residues involved in the interaction. The results obtained imply significant resemblance in the interface residues of E-cadherin that are crucial for homophilic recognition of E-cadherin and heterophilic recognition of N-cadherin as well.


Assuntos
Caderinas , Caderinas/metabolismo , Adesão Celular/fisiologia , Dimerização , Mutação , Ligação Proteica
10.
Int J Biol Macromol ; 210: 494-503, 2022 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-35504420

RESUMO

Tuberculosis, caused by Mycobacterium tuberculosis, is predominantly a disease of the lungs acquired by inhaling mycobacteria from infected individuals via airborne droplets. In order to facilitate their entry into the alveolar macrophages, mycobacteria have a collection of pathogen-associated molecular patterns (PAMPs) on their surface that are known to detect certain pattern recognition receptors present on the surface of host cells. A major group of these PAMPs includes mycobacterial lipoproteins, of which, the 19 kDa surface antigen LpqH, has been reported to play a critical role in both host-pathogen interactions as well as pleiotropic immune regulation. Despite its crucial involvement in tuberculosis, the detailed structure-function relationship of this protein remains to be explored. Here, we report the high-resolution crystal structure of the non-acylated LpqH (LpqH48-159) at a resolution of 1.26 Å, which adopts a unique fold. Flow cytometry-based experiments show that the protein can bind and induce apoptosis in PMA-activated human monocytic cell line THP-1, indicative of the preservation of functionality of the protein. Furthermore, analysis of conservation of LpqH sequences from Mycobacterium species reveals a patch of conserved residues on the surface which may play a role in its binding partner recognition and hence in host-pathogen interaction.


Assuntos
Mycobacterium tuberculosis , Tuberculose , Lipoproteínas/metabolismo , Monócitos/metabolismo , Moléculas com Motivos Associados a Patógenos/metabolismo , Tuberculose/microbiologia
11.
Immunotherapy ; 14(5): 337-350, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35152723

RESUMO

Antigen-specificity of T cells provides important clues to the pathogenesis of T cell-mediated autoimmune diseases and immune-evasion strategies of tumors. Identification of T cell clones involved in autoimmunity or cancer is achieved with soluble peptide-MHC (pMHC) complex multimers. Importantly, these complexes can also be used to manipulate disease-relevant T cells to restore homeostasis of T cell-mediated immune response. While auto-antigen-specific T cells can be deleted or anergized by T cell receptor engagement with cognate pMHC complexes in the absence of costimulation, integration of these complexes in artificial antigen-presenting systems can activate tumor antigen-specific T cells. Here the authors discuss the advancements in pMHC-complex-mediated immunotherapeutic strategies in autoimmunity and cancer and identify the lacunae in these strategies that need to be addressed to facilitate clinical implementation.


Assuntos
Doenças Autoimunes , Neoplasias , Antígenos de Neoplasias , Autoimunidade , Bandagens , Humanos , Neoplasias/terapia , Peptídeos , Receptores de Antígenos de Linfócitos T/genética , Linfócitos T
12.
Drug Discov Today ; 27(3): 900-911, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34775103

RESUMO

Endometrial disorders collectively encompass a broad spectrum of pathologies, including but not limited to endometriosis, endometrial cancer and endometritis. The current therapeutic management of these diseases is associated with several limitations. This has prompted interest in the use of plant-based bioactive compounds as alternative strategies to achieve high therapeutic efficacy and avoid adverse effects. In this context, curcumin, a polyphenol abundantly present in turmeric, is gaining increasing attention for its therapeutic potential to restore homeostasis in endometrial dysfunctionality. We comprehensively review the multifaceted role of curcumin, discussing mechanistic insights in various endometrial pathologies. We also provide an in-depth analysis of the concerns and challenges associated with the role of curcumin in endometrial research and outline a road map for future investigations.


Assuntos
Curcumina , Endometriose , Curcumina/farmacologia , Curcumina/uso terapêutico , Endometriose/tratamento farmacológico , Endometriose/patologia , Feminino , Previsões , Humanos
13.
Hum Vaccin Immunother ; 18(2): 2006026, 2022 04 29.
Artigo em Inglês | MEDLINE | ID: mdl-34886756

RESUMO

Convalescent plasma therapy provides a useful therapeutic tool to treat infectious diseases, especially where no specific therapeutic strategies have been identified. The ongoing pandemic puts back the spotlight on this age-old method as a viable treatment option. In this review, we discuss the usage of this therapy in different diseases including COVID-19, and the possible mechanisms of action. The current review also discusses the progress of therapeutic applications of blood-derivatives, from the simple transfer of immunized animal sera, to the more target-specific intravenous administration of human immunoglobulins from a pool of convalescent individuals, in both infectious and non-infectious diseases of various etiologies.


Assuntos
COVID-19 , SARS-CoV-2 , Animais , Anticorpos Neutralizantes/uso terapêutico , Anticorpos Antivirais , COVID-19/terapia , Imunização Passiva , Pandemias/prevenção & controle , Soroterapia para COVID-19
14.
J Mol Biol ; 432(22): 5938-5950, 2020 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-32976909

RESUMO

T cell costimulation is mediated by the interaction of a number of receptors and ligands present on the surface of the T cell and antigen-presenting cell, respectively. Stimulatory or inhibitory signals from these receptor-ligand interactions work in tandem to preserve immune homeostasis. BTNL2 is a type-1 membrane protein that provides inhibitory signal to T cells and plays an important role in several inflammatory and autoimmune diseases. Therefore, manipulation of the molecular interaction of BTNL2 with its putative receptor could provide strategies to restore immune homeostasis in these diseases. Hence, it is imperative to study the structural characteristics of this molecule, which will provide important insights into its function as well. In this study, the membrane-distal ectodomain of murine BTNL2 was expressed in bacteria as inclusion bodies, refolded in vitro and purified for functional and structural characterization. The domain is monomeric in solution as demonstrated by size-exclusion chromatography and analytical ultracentrifugation, and also binds to its putative receptor on naïve B cells and activated T cell subsets. Importantly, for the first time, we report the structure of BTNL2 as determined by solution NMR spectroscopy and also the picosecond-nanosecond timescale backbone dynamics of this domain. The N-terminal ectodomain of BTNL2, which was able to inhibit T cell function as well, exhibits distinctive structural features. The N-terminal ectodomain of BTNL2 has a significantly reduced surface area in the front sheet due to the non-canonical conformation of the CC' loop, which provides important insights into the recognition of its presently unknown binding partner.


Assuntos
Butirofilinas/química , Domínios de Imunoglobulina , Linfócitos T/imunologia , Animais , Butirofilinas/genética , Homeostase , Ligantes , Ativação Linfocitária , Proteínas de Membrana/química , Camundongos , Modelos Moleculares , Conformação Proteica
15.
Cancer Rep (Hoboken) ; 2(4): e1160, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-32721130

RESUMO

BACKGROUND: With the recent advances in the understanding of the interaction of the immune system with developing tumor, it has become imperative to consider the immunological parameters for both cancer diagnosis and disease prognosis. Additionally, in the era of emerging immunotherapeutic strategies in cancer, it is very important to follow the treatment outcome and also to predict the correct immunotherapeutic strategy in individual patients. There being enormous heterogeneity among tumors at different sites or between primary and metastatic tumors in the same individual, or interpatient heterogeneity, it is very important to study the tumor-immune interaction in the tumor microenvironment and beyond. Importantly, molecular tools and markers identified for such studies must be suitable for monitoring in a noninvasive manner. RECENT FINDINGS: Recent studies have shown that the immune checkpoint molecules play a key role in the development and progression of tumors. In-depth studies of these molecules have led to the development of most of the cancer immunotherapeutic reagents that are currently either in clinical use or under different phases of clinical trials. Interestingly, many of these cell surface molecules undergo alternative splicing to produce soluble isoforms, which can be tracked in the serum of patients. CONCLUSIONS: Several studies demonstrate that the serum levels of these soluble isoforms could be used as noninvasive markers for cancer diagnosis and disease prognosis or to predict patient response to specific therapeutic strategies.


Assuntos
Antineoplásicos Imunológicos/uso terapêutico , Biomarcadores Tumorais/sangue , Proteínas de Checkpoint Imunológico/sangue , Neoplasias/diagnóstico , Processamento Alternativo , Antineoplásicos Imunológicos/farmacologia , Biomarcadores Tumorais/genética , Progressão da Doença , Resistencia a Medicamentos Antineoplásicos/imunologia , Humanos , Proteínas de Checkpoint Imunológico/genética , Neoplasias/sangue , Neoplasias/tratamento farmacológico , Neoplasias/mortalidade , Prognóstico , Intervalo Livre de Progressão , Isoformas de Proteínas/sangue , Isoformas de Proteínas/genética , Microambiente Tumoral/efeitos dos fármacos , Microambiente Tumoral/imunologia
16.
Mol Ther ; 24(1): 146-55, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26412590

RESUMO

Due to their ability to knock down the expression of any gene, siRNAs have been heralded as ideal candidates for treating a wide variety of diseases, including those involving "undruggable" targets. However, the therapeutic potential of siRNAs remains severely limited by a lack of effective delivery vehicles. Recently, lipid nanoparticles (LNPs) containing ionizable cationic lipids have been developed for hepatic siRNA delivery. However, their suitability for delivery to other cell types has not been determined. We have modified LNPs for preferential targeting to dendritic cells (DCs), central regulators of immune responses. To achieve directed delivery, we coated LNPs with a single-chain antibody (scFv; DEC-LNPs), specific to murine DEC205, which is highly expressed on distinct DC subsets. Here we show that injection of siRNAs encapsulated in DEC-LNPs are preferentially delivered to DEC205(+) DCs. Gene knockdown following uptake of DEC-LNPs containing siRNAs specific for the costimulatory molecules CD40, CD80, and CD86 dramatically decreases gene expression levels. We demonstrate the functionality of this knockdown with a mixed lymphocyte response (MLR). Overall, we report that injection of LNPs modified to restrict their uptake to a distinct cell population can confer profound gene knockdown, sufficient to inhibit powerful immune responses like the MLR.


Assuntos
Antígeno B7-1/metabolismo , Antígeno B7-2/metabolismo , Antígenos CD40/metabolismo , Células Dendríticas/imunologia , Lipídeos/química , RNA Interferente Pequeno/administração & dosagem , Animais , Regulação da Expressão Gênica , Injeções , Fígado/metabolismo , Camundongos , Terapia de Alvo Molecular , Nanopartículas/administração & dosagem , Nanopartículas/química
17.
Immunology ; 144(4): 631-40, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25333865

RESUMO

Type 1 diabetes is characterized by T-cell-mediated destruction of the insulin-producing ß cells in pancreatic islets. A number of islet antigens recognized by CD8 T cells that contribute to disease pathogenesis in non-obese diabetic (NOD) mice have been identified; however, the antigenic specificities of the majority of the islet-infiltrating cells have yet to be determined. The primary goal of the current study was to identify candidate antigens based on the level and specificity of expression of their genes in mouse islets and in the mouse ß cell line MIN6. Peptides derived from the candidates were selected based on their predicted ability to bind H-2K(d) and were examined for recognition by islet-infiltrating T cells from NOD mice. Several proteins, including those encoded by Abcc8, Atp2a2, Pcsk2, Peg3 and Scg2, were validated as antigens in this way. Interestingly, islet-infiltrating T cells were also found to recognize peptides derived from proglucagon, whose expression in pancreatic islets is associated with α cells, which are not usually implicated in type 1 diabetes pathogenesis. However, type 1 diabetes patients have been reported to have serum autoantibodies to glucagon, and NOD mouse studies have shown a decrease in α cell mass during disease pathogenesis. Our finding of islet-infiltrating glucagon-specific T cells is consistent with these reports and suggests the possibility of α cell involvement in development and progression of disease.


Assuntos
Autoantígenos/imunologia , Linfócitos T CD8-Positivos/imunologia , Diabetes Mellitus Tipo 1/imunologia , Ilhotas Pancreáticas/imunologia , Proglucagon/imunologia , Animais , Autoantígenos/metabolismo , Autoimunidade , Linfócitos T CD8-Positivos/metabolismo , Linhagem Celular Tumoral , Biologia Computacional , Diabetes Mellitus Tipo 1/metabolismo , Modelos Animais de Doenças , ELISPOT , Mapeamento de Epitopos , Epitopos de Linfócito T/imunologia , Epitopos de Linfócito T/metabolismo , Antígenos H-2/imunologia , Antígenos H-2/metabolismo , Interferon gama/metabolismo , Testes de Liberação de Interferon-gama , Ilhotas Pancreáticas/metabolismo , Camundongos Endogâmicos NOD , Proglucagon/metabolismo , Ligação Proteica
18.
J Immunol ; 193(5): 2135-46, 2014 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-25063871

RESUMO

Self-reactive T cells must escape thymic negative selection to mediate pathogenic autoimmunity. In the NOD mouse model of autoimmune diabetes, several ß cell-cytotoxic CD8 T cell populations are known, with the most aggressive of these represented by AI4, a T cell clone with promiscuous Ag-recognition characteristics. We identified a long-elusive ß cell-specific ligand for AI4 as an unusually short H-2D(b)-binding 7-mer peptide lacking a C-terminal anchor residue and derived from the insulin A chain (InsA14-20). Crystallography reveals that compensatory mechanisms permit peptides lacking a C-terminal anchor to bind sufficiently to the MHC to enable destructive T cell responses, yet allow cognate T cells to avoid negative selection. InsA14-20 shares two solvent-exposed residues with previously identified AI4 ligands, providing a structural explanation for AI4's promiscuity. Detection of AI4-like T cells, using mimotopes of InsA14-20 with improved H-2D(b)-binding characteristics, establishes the AI4-like T cell population as a consistent feature of the islet infiltrates of NOD mice. Our work establishes undersized peptides as previously unrecognized targets of autoreactive CD8 T cells and presents a strategy for their further exploration as Ags in autoimmune disease.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Diabetes Mellitus Experimental/imunologia , Diabetes Mellitus Tipo 1/imunologia , Antígenos de Histocompatibilidade Classe I/imunologia , Peptídeos/imunologia , Animais , Linfócitos T CD8-Positivos/patologia , Cristalografia por Raios X , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/patologia , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/patologia , Antígenos de Histocompatibilidade Classe I/química , Antígenos de Histocompatibilidade Classe I/genética , Camundongos , Camundongos Endogâmicos NOD , Camundongos Transgênicos , Peptídeos/química , Peptídeos/genética , Relação Estrutura-Atividade
19.
Int Immunol ; 25(11): 651-60, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24021877

RESUMO

CD8⁺ T cells specific for islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP) have been implicated in type 1 diabetes in both humans and non-obese diabetic (NOD) mice, in which T cells specific for IGRP206₋214 are highly prevalent. We sought to manipulate these pathogenic T cells by exploiting the ability of steady-state dendritic cells (DCs) to present antigens in a tolerogenic manner. The endocytic receptor DEC-205 was utilized to deliver an IGRP206₋214 mimotope to DCs in NOD mice, and the impact of this delivery on a polyclonal population of endogenous islet-reactive cognate T cells was determined. Assessment of islet-infiltrating CD8⁺ T cells showed a decrease in the percentage, and the absolute number, of endogenous IGRP206₋214-specific T cells when the mimotope was delivered to DCs, compared with delivery of a specificity control. Employing an adoptive transfer system, deletion of CD8⁺ T cells as a result of DEC-205-mediated antigen targeting was found to occur independently of programmed death-1 (PD-1) and its ligand (PD-L1), both often implicated in the regulation of peripheral T-cell tolerance. Given its promise for the manipulation of self-reactive polyclonal T cells demonstrated here, the distinctive characteristics of this antigen delivery system will be important to appreciate as its potential as an intervention for autoimmune diseases continues to be investigated.


Assuntos
Antígenos CD/imunologia , Antígenos/imunologia , Antígeno B7-H1 , Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/imunologia , Células Dendríticas/imunologia , Lectinas Tipo C/imunologia , Receptor de Morte Celular Programada 1 , Receptores de Superfície Celular/imunologia , Animais , Anticorpos/imunologia , Reações Antígeno-Anticorpo , Antígeno B7-H1/metabolismo , Células Dendríticas/citologia , Contagem de Linfócitos , Camundongos , Camundongos Endogâmicos NOD , Camundongos Transgênicos , Antígenos de Histocompatibilidade Menor , Receptor de Morte Celular Programada 1/metabolismo
20.
J Immunol ; 188(11): 5766-75, 2012 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-22539795

RESUMO

Type 1 diabetes is an autoimmune disease characterized by T cell responses to ß cell Ags, including insulin. Investigations employing the NOD mouse model of the disease have revealed an essential role for ß cell-specific CD8(+) T cells in the pathogenic process. As CD8(+) T cells specific for ß cell Ags are also present in patients, these reactivities have the potential to serve as therapeutic targets or markers for autoimmune activity. NOD mice transgenic for human class I MHC molecules have previously been employed to identify T cell epitopes having important relevance to the human disease. However, most studies have focused exclusively on HLA-A*0201. To broaden the reach of epitope-based monitoring and therapeutic strategies, we have looked beyond this allele and developed NOD mice expressing human ß(2)-microglobulin and HLA-A*1101 or HLA-B*0702, which are representative members of the A3 and B7 HLA supertypes, respectively. We have used islet-infiltrating T cells spontaneously arising in these strains to identify ß cell peptides recognized in the context of the transgenic HLA molecules. This work has identified the insulin C-peptide as an abundant source of CD8(+) T cell epitopes. Responses to these epitopes should be of considerable utility for immune monitoring, as they cannot reflect an immune reaction to exogenously administered insulin, which lacks the C-peptide. Because the peptides bound by one supertype member were found to bind certain other members also, the epitopes identified in this study have the potential to result in therapeutic and monitoring tools applicable to large numbers of patients and at-risk individuals.


Assuntos
Peptídeo C/metabolismo , Linfócitos T CD8-Positivos/imunologia , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/imunologia , Epitopos de Linfócito T/imunologia , Antígeno HLA-A2/química , Animais , Peptídeo C/genética , Peptídeo C/imunologia , Linfócitos T CD8-Positivos/química , Linfócitos T CD8-Positivos/metabolismo , Células Cultivadas , Diabetes Mellitus Tipo 1/metabolismo , Epitopos de Linfócito T/metabolismo , Feminino , Predisposição Genética para Doença , Antígeno HLA-A11/genética , Antígeno HLA-A11/metabolismo , Antígeno HLA-A2/genética , Antígeno HLA-A2/imunologia , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos NOD , Camundongos Transgênicos , Ligação Proteica/imunologia
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