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Objectives: Prevalence of irregular menstrual cycle ranges from 81.7% to 96.3%. Recent research suggested that homeopathy is one of the most popular choices for women with various gynecological disorders. This trial was aimed at differentiating individualized homeopathic medicinal products (IHMPs) from identical-looking placebos in the treatment of menstrual irregularities in early reproductive women. Design: Double-blind, randomized (1:1), two parallel arms, placebo-controlled trial. Setting: D. N. De Homoeopathic Medical College & Hospital, Kolkata, West Bengal, India. Subjects: Ninety-two females with menstrual irregularities. Interventions: Group verum (n = 46; IHMPs plus concomitant care) versus group control (n = 46; placebos plus concomitant care). Outcome Measures: Primary-The proportion of early reproductive females in whom menstrual irregularities can be corrected for consecutive three cycles; Secondary-Menstrual Distress Questionnaire (MDQ) total score; all of them were measured at baseline and every month, up to 4 months. Results: Intention-to-treat sample (n = 92) was analyzed. Group differences were examined by chi-squared tests with categorical outcomes, two-way repeated measure analysis of variance accounting for the time-effect interactions, and unpaired t-tests comparing the mean estimates obtained individually every month. The level of significance was set at p < 0.05 two-tailed. After 4 months of intervention, the group difference in the primary outcome was nonsignificant statistically-IHMPs: 22/46 v/s placebo: 24/46, chi-square (Yates corrected) = 0.043, p = 0.835. The improvement observed in the MDQ total score (F1,90 = 0.054, p = 0.816) and subscales scores were higher in the IHMPs group than in placebos, however statistically nonsignificant in most of the occasions, except for the behavioral change subscale (F1,90 = 0.029, p < 0.001). Pulsatilla nigricans was the most frequently prescribed medicine. Kent's Repertory and Zandvoort's Complete Repertory were the most frequently used repertories. No harm or serious adverse events were reported from either group. Conclusions: The analysis failed to demonstrate clearly that IHMPs were effective beyond placebos in all but one of the outcomes. More appropriate outcome measures may be sought for future trials. Clinical Trial Registration Number: CTRI/2022/04/041659.
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Background and Aim: To assess the spectrum of hepatic involvement in children with dengue fever (DF) and prediction of severity of dengue infection by early detection of elevated liver enzymes. Methods: This prospective observational study was conducted at a tertiary care hospital from June 2019 to September 2019. Children admitted with DF were included. Severity of DF was graded as dengue without warning sign (DNWS), with warning sign (DWS), and severe dengue fever (SDF) according to WHO criteria. Liver injury (LI) was defined as alanine aminotransferase (ALT) more than upper limit of normal irrespective of sex. Results: Of 190 children (male, 109) with DF, 60 had DNWS, 49 had DWS, and 81 had SDF. A total of 100 children (52.6%) had LI. The distribution of hepatic involvement spectrum involves hepatomegaly (26.3%), hepatic tenderness (25.2%), features of acute liver failure (1.5%), raised level of ALT (52.6%), raised level of aspartateaminotransferase (AST) (65.8%), prolonged prothrombin time (7.3%), and reduced level of serum albumin (44.7%) in children. Of them, 5.8% and 6.8% of children had >tenfold increase in ALT and AST values. The degree of liver function derangement significantly (P < 0.05) increased with DF severity. In our study, ALT at 422 IU/L (10 times upper limit of normal [ULN]) and AST 689 IU/L (17 times ULN) had similar sensitivity and specificity as WHO recommended cutoff of 1000 IU/L (25 times of ULN) to detect SDF. Conclusion: ALT ≥10 times and AST ≥17 times of ULN are as sensitive as ≥25 times (as recommended by WHO) to detect SDF.
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In drug development, the dog is often used as a model for non-rodent preclinical safety studies. In particular, immunophenotyping in dogs can be important to characterize the toxicological profile of a test item. A wide range of antibodies specific to surface antigens is needed, however, commercially available antibodies to dog are scarce. To date, numerous studies have reported the cross-reactivity of human monoclonal antibodies with canine peripheral blood mononuclear cells (PBMC). In this study, we aimed to increase the number of canine-specific antibodies and took a rather novel approach to further determine cross-reactivity of 378 human recombinant antibodies lacking Fc regions to surface antigens on canine PBMC. The screening resulted in 30 human monoclonal antibodies well reactive to canine PBMC. Sequence homology of the targeted human and canine antigens was analyzed with Basic Local Alignment Search Tool. Thirteen human cross-reactive antibodies of interest were analyzed with cells from canine whole blood in combination with lineage markers. Finally, ten antibodies were identified as useful markers for the application in dog. Except for CD27, the remaining nine antibodies are already commercially available human cross-reactive antibodies. This study provides a new source for all ten antibodies described here.
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Anticorpos Monoclonais , Leucócitos Mononucleares , Humanos , Cães , Animais , Reações Cruzadas , Antígenos de Superfície , Imunofenotipagem/veterinária , Citometria de Fluxo/veterináriaRESUMO
The COVID-19 pandemic has generated a major interest in designing inhibitors to prevent SARS-CoV-2 binding on host cells to protect against infection. One promising approach to such research utilizes molecular dynamics simulation to identify potential inhibitors that can prevent the interaction between spike (S) protein on the virus and angiotensin converting enzyme 2 (ACE2) receptor on the host cells. In these studies, many groups have chosen to exclude the ACE2-bound zinc (Zn) ion, which is critical for its enzymatic activity. While the relatively distant location of Zn ion from the S protein binding site (S1 domain), combined with the difficulties in modeling this ion has motivated the decision of exclusion, Zn can potentially contribute to the structural stability of the entire protein, and thus, may have implications on S protein-ACE2 interaction. In this study, the authors model both the ACE2-S1 and ACE2-inhibitor (mAb) system to investigate if there are variations in structure and the readouts due to the presence of Zn ion. Although distant from the S1 or inhibitor binding region, inclusion/exclusion of Zn has statistically significant effects on the structural stability and binding free energy in these systems. In particular, the binding free energy of the ACE2-S1 and ACE2-inhibitor structures is - 3.26 and - 14.8 kcal/mol stronger, respectively, in the Zn-bound structure than in the Zn-free structures. This finding suggests that including Zn may be important in screening potentially inhibitors and may be particularly important in modeling monoclonal antibodies, which may be more sensitive to changes in antigen structure.
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COVID-19 , Humanos , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/metabolismo , Enzima de Conversão de Angiotensina 2/química , Enzima de Conversão de Angiotensina 2/metabolismo , Pandemias , Zinco , Ligação ProteicaRESUMO
Among the multiple SARS-CoV-2 variants recently reported, the Delta variant has generated the most perilous and widespread effects. Another variant, Omicron, has been identified specifically for its high transmissibility. Omicron contains numerous spike (S) protein mutations and numbers much larger than those of its predecessor variants. In this report, the author has discussed some essential structural aspects and time-based structure changes of a selected set of spike protein mutations within the Delta and Omicron variants. The expected impact of multiple point mutations within the spike protein's receptor-binding domain (RBD) and S1 of these variants are examined. Additionally, the RBDs of the more recently emerged subvariants BA.4, BA.5, and BA.2.12.1 are discussed. Within the latter group, BA.5 represents the most prevalent form of SARS-CoV-2 globally until recently. This computational work also briefly explores the temporal mutation profile for the currently circulating variants of interest (VOIs), variants under monitoring (VUMs), and variants being monitored (VBMs) including XBB.1.5, BQ.1, BA.2.75, CH.1.1, XBB, XBF, EG.5 (or Eris), and BA.2.86 (or Pirola). It is expected that these structural data can facilitate the tasks of identifying drug targets and neutralizing antibodies for the evolving variants/subvariants of SARS-CoV-2.
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Genetic defects in SLC26A3 (DRA), an intestinal Cl-/HCO3- exchanger, result in congenital chloride diarrhea (CLD), marked by lifelong acidic diarrhea and a high risk of inflammatory bowel disease. Slc26a3-/- mice serve as a model to understand the pathophysiology of CLD and search for treatment options. This study investigates the microbiota changes in slc26a3-/- colon, the genotype-related causes for the observed microbiota alterations, its inflammatory potential, as well as the corresponding host responses. The luminal and the mucosa-adherent cecal and colonic microbiota of cohoused slc26a3-/- and wt littermates were analyzed by 16S rRNA gene sequencing. Fecal microbiota transfer from cohoused slc26a3-/- and wt littermates to germ-free wt mice was performed to analyze the stability and the inflammatory potential of the communities.The cecal and colonic luminal and mucosa-adherent microbiota of slc26a3-/- mice was abnormal from an early age, with a loss of diversity, of short-chain fatty acid producers, and an increase of pathobionts. The transfer of slc26a3-/- microbiota did not result in intestinal inflammation and the microbial diversity in the recipient mice normalized over time. A strong increase in the expression of Il22, Reg3ß/γ, Relmß, and other proteins with antimicrobial functions was observed in slc26a3-/- colon from juvenile age, while the mucosal and systemic inflammatory signature was surprisingly mild. The dysbiotic microbiota, low mucosal pH, and mucus barrier defect in slc26a3-/- colon are accompanied by a stark upregulation of the expression of a panel of antimicrobial proteins. This may explain the low inflammatory burden in the gut of these mice.
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Disbiose , Microbioma Gastrointestinal , Animais , Peptídeos Antimicrobianos , Antiporters/genética , Colo/metabolismo , Disbiose/genética , Disbiose/metabolismo , Mucosa Intestinal/metabolismo , Camundongos , RNA Ribossômico 16S/genética , Transportadores de Sulfato/genética , Transportadores de Sulfato/metabolismo , Regulação para CimaRESUMO
The severity of COVID-19 has been observed throughout the world as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) globally claimed more than 2 million lives and left a devastating impact worldwide. Recently several virulent mutant strains of this virus, such as the B.1.1.7, B.1.351, and P1 lineages, have emerged with initial predominance in UK, South Africa, and Brazil. Another extremely pathogenic B.1.617 lineage and its sub-lineages, first detected in India, are now affecting some countries at notably stronger spread-rates. The present paper computationally examines the time-based structures of B.1.1.7, B.1.351, and P1 lineages with selected spike protein mutations. The mutations in the more recently found B.1.617 lineage and its sub-lineages are explored, and the implications for multiple point mutations of the spike protein's receptor-binding domain (RBD) are described. The selected S1 mutations within the highly contagious B.1.617.2 sub-lineage, also known as the delta variant, are examined as well.
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COVID-19 , SARS-CoV-2 , Humanos , Mutação , SARS-CoV-2/genética , Glicoproteína da Espícula de Coronavírus/metabolismoRESUMO
The intestinal microbiota modulates IL-22 production in the intestine, including the induction of IL-22-producing CD4+ T helper cells. Which specific bacteria are responsible for the induction of these cells is less well understood. Here, we demonstrate through the use of novel gnotobiotic knock-in reporter mice that segmented filamentous bacteria (SFB), which are known for their ability to induce Th17 cells, also induce distinct IL-17A negative CD4+ T cell populations in the intestine. A subset of these cells instead produces IL-22 upon restimulation ex vivo and also during enteric infections. Furthermore, they produce a distinct set of cytokines compared to Th17 cells including the differential expression of IL-17F and IFN-γ. Importantly, genetic models demonstrate that these cells, presumably Th22 cells, develop independently of intestinal Th17 cells. Together, our data identifies that besides Th17, SFB also induces CD4+ T cell populations, which serve as immediate source of IL-22 during intestinal inflammation.
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Linfócitos T CD4-Positivos/imunologia , Microbioma Gastrointestinal/imunologia , Interleucinas/imunologia , Células Th17/imunologia , Animais , Linfócitos T CD4-Positivos/metabolismo , Interleucinas/biossíntese , Mucosa Intestinal/microbiologia , Camundongos , Camundongos Endogâmicos C57BL , Salmonella typhi , Células Th17/metabolismo , Febre Tifoide/imunologia , Febre Tifoide/microbiologia , Interleucina 22RESUMO
Diverse microbial signatures within the intestinal microbiota have been associated with intestinal and systemic inflammatory diseases, but whether these candidate microbes actively modulate host phenotypes or passively expand within the altered microbial ecosystem is frequently not known. Here we demonstrate that colonization of mice with a member of the genus Prevotella, which has been previously associated to colitis in mice, exacerbates intestinal inflammation. Our analysis revealed that Prevotella intestinalis alters composition and function of the ecosystem resulting in a reduction of short-chain fatty acids, specifically acetate, and consequently a decrease in intestinal IL-18 levels during steady state. Supplementation of IL-18 to Prevotella-colonized mice was sufficient to reduce intestinal inflammation. Hence, we conclude that intestinal Prevotella colonization results in metabolic changes in the microbiota, which reduce IL-18 production and consequently exacerbate intestinal inflammation, and potential systemic autoimmunity.
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Infecções por Bacteroidaceae/imunologia , Infecções por Bacteroidaceae/microbiologia , Microbioma Gastrointestinal/imunologia , Interações Hospedeiro-Patógeno/imunologia , Mucosa Intestinal/imunologia , Mucosa Intestinal/microbiologia , Prevotella/imunologia , Imunidade Adaptativa , Animais , Citocinas/metabolismo , Modelos Animais de Doenças , Suscetibilidade a Doenças , Mediadores da Inflamação/metabolismo , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Metagenoma , Metagenômica/métodos , Camundongos , Camundongos Knockout , Mucosite/etiologia , Mucosite/metabolismo , Mucosite/patologiaRESUMO
BACKGROUND: The cross-talk between the host and its microbiota plays a key role in the promotion of health. The production of metabolites such as polyamines by intestinal-resident bacteria is part of this symbiosis shaping host immunity. The polyamines putrescine, spermine, and spermidine are abundant within the gastrointestinal tract and might substantially contribute to gut immunity. OBJECTIVE: We aimed to characterize the polyamine spermidine as a modulator of T-cell differentiation and function. METHODS: Naive T cells were isolated from wild-type mice or cord blood from healthy donors and submitted to polarizing cytokines, with and without spermidine treatment, to evaluate CD4+ T-cell differentiation in vitro. Moreover, mice were subjected to oral supplementation of spermidine, or its precursor l-arginine, to assess the frequency and total numbers of regulatory T (Treg) cells in vivo. RESULTS: Spermidine modulates CD4+ T-cell differentiation in vitro, preferentially committing naive T cells to a regulatory phenotype. After spermidine treatment, activated T cells lacking the autophagy gene Atg5 fail to upregulate Foxp3 to the same extent as wild-type cells. These results indicate that spermidine's polarizing effect requires an intact autophagic machinery. Furthermore, dietary supplementation with spermidine promotes homeostatic differentiation of Treg cells within the gut and reduces pathology in a model of T-cell transfer-induced colitis. CONCLUSION: Altogether, our results highlight the beneficial effects of spermidine, or l-arginine, on gut immunity by promoting Treg cell development.
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Diferenciação Celular/efeitos dos fármacos , Colite/imunologia , Imunidade nas Mucosas/efeitos dos fármacos , Espermidina/farmacologia , Linfócitos T Reguladores/imunologia , Animais , Diferenciação Celular/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos KnockoutRESUMO
Prevotella spp. are a dominant bacterial genus within the human gut. Multiple Prevotella spp. co-exist in some individuals, particularly those consuming plant-based diets. Additionally, Prevotella spp. exhibit variability in the utilization of diverse complex carbohydrates. To investigate the relationship between Prevotella competition and diet, we isolated Prevotella species from the mouse gut, analyzed their genomes and transcriptomes in vivo, and performed competition experiments between species in mice. Diverse dominant Prevotella species compete for similar metabolic niches in vivo, which is linked to the upregulation of specific polysaccharide utilization loci (PULs). Complex plant-derived polysaccharides are required for Prevotella spp. expansion, with arabinoxylans having a prominent impact on species abundance. The most dominant Prevotella species encodes a specific tandem-repeat trsusC/D PUL that enables arabinoxylan utilization and is conserved in human Prevotella copri strains, particularly among those consuming a vegan diet. These findings suggest that efficient (arabino)xylan-utilization is a factor contributing to Prevotella dominance.
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Microbioma Gastrointestinal , Polissacarídeos/metabolismo , Prevotella/crescimento & desenvolvimento , Xilanos/metabolismo , Animais , DNA Bacteriano , Loci Gênicos , Genoma Bacteriano , Glicosídeo Hidrolases/genética , Glicosiltransferases/genética , Humanos , Metagenômica , Camundongos , Camundongos Endogâmicos C57BL , Filogenia , Prevotella/classificação , Prevotella/isolamento & purificação , RNA Ribossômico 16S , Transcriptoma , Veganos , Sequenciamento Completo do GenomaRESUMO
Structure-based molecular designs play a critical role in the context of next generation drug development. Besides their fundamental scientific aspects, the findings established in this approach have significant implications in the expansions of target-based therapies and vaccines. Interleukin-18 (IL-18), also known as interferon gamma (IFN-γ) inducing factor, is a pro-inflammatory cytokine. The IL-18 binds first to the IL-18α receptor and forms a lower affinity complex. Upon binding with IL-18ß a hetero-trimeric complex with higher affinity is formed that initiates the signal transduction process. The present study, including structural and molecular dynamics simulations, takes a close look at the structural stabilities of IL-18 and IL-18 receptor-bound ligand structures as functions of time. The results help to identify the conformational changes of the ligand due to receptor binding, as well as the structural orders of the apo and holo IL-18 protein complexes.
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Interleucina-18/química , Simulação de Dinâmica Molecular , Humanos , Conformação Proteica , SoftwareRESUMO
BACKGROUND: Histoplasmosis is a rare infectious condition with mainly pulmonary involvement. Disseminated histoplasmosis may occur in immunocompromised condition. It can present in different ways but jaundice and ascites is very uncommon. CASE PRESENTATION: A 8- year old girl visited to department of pediatric gastroenterology & nutrition, Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh. Child presented with fever, jaundice and abdominal distension for 2 ½ months. There was no history of contact with tuberculosis patient and travelling to kala-azar, malaria endemic zone and no history of previous jaundice, blood or blood product transfusion, history of sib death, family history of jaundice or neuropsychiatric disorder, significant weight loss. On general examination she was fretful, febrile, moderately icteric, mildly pale, vitally stable, severely wasted and moderately stunted, skin survey revealed infected scabies, BCG vaccine mark was absent, generalized lymphadenopathy, hepato-splenomegaly and ascites present. After evaluating the physical findings, several investigations was done including lymphnode biopsy, then the case was finally diagnosed as Disseminated histoplasmosis with portal hypertension. Child was treated with injectable Deoxycholate Amphotericin B for 28 days and improved on follow up. CONCLUSION: We suggest that children presenting with fever, jaundice, lymphadenopathy and hepatosplenomegaly and portal hypertension, disseminated histoplasmosis can be one differential.
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Histoplasmose , Hipertensão Portal , Anfotericina B/uso terapêutico , Bangladesh , Criança , Feminino , Febre , Histoplasmose/complicações , Histoplasmose/diagnóstico , Histoplasmose/tratamento farmacológico , Humanos , Hipertensão Portal/complicações , Hipertensão Portal/diagnósticoRESUMO
The Japanese encephalitis virus (JEV) is one of the vector borne causes of encephalitis found in southeastern Asia. This positive single-stranded RNA virus is a member of the Flaviviridae family, which notably includes dengue, tick-borne, West Nile, Zika as well as yellow fever, and transmits to humans by infected mosquitos. The main site of interactions for antibodies against this virus is the envelope protein domain III (ED3). The present report investigates the time-dependent structural and conformational changes of JEV ED3 functional epitopes and escape mutants by computer simulations. The results indicate the presence of significant structural differences between the functional epitopes and the escape mutants. Mutation-induced structural/conformational instabilities of this type can decrease the antibody neutralization activity. Among the different escape mutants studied here, Ser40Lys/Asp41Arg appear to be most unstable, while Ser40Glu/Asp41Leu exhibit the lowest structural variations. The highest level of escape mutation observed in Ser40Lys is linked to the relatively higher values of root mean square deviation/fluctuation found in the molecular dynamics simulation of this protein. Secondary-structure deviations and depletion of H bonding are other contributing factors to the protein's increased instability. Overall, the proteins with residue 41 mutations are found to be structurally more ordered than those with residue 40 mutations. The detailed time-based structural assessment of the mutant epitopes described here may contribute to the development of novel vaccines and antiviral drugs necessary to defend against future outbreaks of JEV escape mutants.
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Vírus da Encefalite Japonesa (Espécie)/fisiologia , Encefalite Japonesa/imunologia , Proteínas do Envelope Viral/imunologia , Vacinas Virais/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Neutralizantes/metabolismo , Variação Antigênica , Simulação por Computador , Culicidae , Humanos , Ligação de Hidrogênio , Evasão da Resposta Imune/genética , Simulação de Dinâmica Molecular , Mutação/genética , Conformação Proteica , Domínios Proteicos/genética , Relação Estrutura-Atividade , Proteínas do Envelope Viral/química , Proteínas do Envelope Viral/genéticaRESUMO
Recent developments of mass spectrometry (MS) allow us to identify, estimate, and characterize proteins and protein complexes. At the same time, structural biology helps to determine the protein structure and its structure-function relationship. Together, they aid to understand the protein structure, property, function, protein-complex assembly, protein-protein interaction, and dynamics. The present chapter is organized with illustrative results to demonstrate how experimental mass spectrometry can be combined with computational structural biology for detailed studies of protein's structures. We have used tumor differentiation factor protein/peptide as ligand and Hsp70/Hsp90 as receptor protein as examples to study ligand-protein interaction. To investigate possible protein conformation, we will describe two proteins-lysozyme and myoglobin. As an application of MS-based assignment of disulfide bridges, the case of the spider venom polypeptide Phα1ß will also be discussed.
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Biologia Computacional , Espectrometria de Massas , Peptídeos/análise , Proteínas/análise , Conformação ProteicaRESUMO
The inflammatory cytokine, interleukin-2 (IL-2), is an important regulator of cellular functions. This relatively less studied member of the interleukin protein family is responsible for multiple immuno-modulatory and immuno-stimulatory tasks, like T cell activation, triggering of natural killer cells, inflammation, as well as proliferation and progression of autoimmune diseases and cancers. In this communication we report the temporally variant structural aspects of the IL-2 ligand and its receptor interfaces, based on the available crystal structures. The intended goal of this effort is to generate simulated results that could potentially aid the designs of novel structure based therapeutics.
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Interleucina-2/química , Biologia Computacional , Cristalografia por Raios X , Humanos , Inflamação/metabolismo , Interleucina-2/metabolismo , Modelos Moleculares , Simulação de Acoplamento Molecular , Neoplasias/metabolismo , Conformação Proteica , Mapas de Interação de Proteínas , Receptores de Interleucina-2/química , Receptores de Interleucina-2/metabolismo , Transdução de SinaisRESUMO
Foxp3+ regulatory T cells (Treg cells) are crucial for the maintenance of immune homeostasis both in lymphoid tissues and in non-lymphoid tissues. Here we demonstrate that the ability of intestinal Treg cells to constrain microbiota-dependent interleukin (IL)-17-producing helper T cell (TH17 cell) and immunoglobulin A responses critically required expression of the transcription factor c-Maf. The terminal differentiation and function of several intestinal Treg cell populations, including RORγt+ Treg cells and follicular regulatory T cells, were c-Maf dependent. c-Maf controlled Treg cell-derived IL-10 production and prevented excessive signaling via the kinases PI(3)K (phosphatidylinositol-3-OH kinase) and Akt and the metabolic checkpoint kinase complex mTORC1 (mammalian target of rapamycin) and expression of inflammatory cytokines in intestinal Treg cells. c-Maf deficiency in Treg cells led to profound dysbiosis of the intestinal microbiota, which when transferred to germ-free mice was sufficient to induce exacerbated intestinal TH17 responses, even in a c-Maf-competent environment. Thus, c-Maf acts to preserve the identity and function of intestinal Treg cells, which is essential for the establishment of host-microbe symbiosis.
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Imunoglobulina A/biossíntese , Intestinos/imunologia , Microbiota , Proteínas Proto-Oncogênicas c-maf/fisiologia , Linfócitos T Reguladores/imunologia , Células Th17/imunologia , Animais , Células Cultivadas , Colite/imunologia , Citocinas/metabolismo , Disbiose , Regulação da Expressão Gênica , Homeostase , Interleucina-10/biossíntese , Camundongos Endogâmicos C57BL , Proteínas Proto-Oncogênicas c-maf/genética , Proteínas Proto-Oncogênicas c-maf/metabolismo , Linfócitos T Reguladores/enzimologiaRESUMO
The interactions between the tumor necrosis factor (TNF) and its receptor molecule are responsible for various signaling networks that are central to the functioning of human immune homeostasis. The present work is a computational study of certain structural aspects of this cell-signaling protein, specifically focusing on the molecular level analyses of the TNF receptor (TNF-R), guided by its crystallographic structure. We also examine the possible binding sites of the TNF onto TNF-R, and the associated interactions. The structural and conformational variations in the TNF-R and TNF bound TNF-R systems are examined in this context using molecular dynamics (MD) simulations. The time dependent variations of the dimeric TNF-R structures are compared with, and shown to be steadier than their isolated monomers. This dimeric stability is favored under acidic conditions. The results are used to further illustrate how 3D modeling and computer simulations can aid the structure-based approach to probing a ligand-receptor system.
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Modelos Moleculares , Receptores do Fator de Necrose Tumoral/química , Fatores de Necrose Tumoral/química , Cristalografia por Raios X , Humanos , Ligação Proteica , Conformação Proteica , SoftwareRESUMO
Inflammatory bowel disease is associated with extraintestinal diseases such as primary sclerosing cholangitis in the liver. Interestingly, it is known that an imbalance between Foxp3+ regulatory T cells (Treg) and Th17 cells is involved in inflammatory bowel disease and also in primary sclerosing cholangitis. To explain these associations, one hypothesis is that intestinal inflammation and barrier defects promote liver disease because of the influx of bacteria and inflammatory cells to the liver. However, whether and how this is linked to the Treg and Th17 cell imbalance is unclear. To address this, we used dextran sodium sulfate (DSS) and T cell transfer colitis mouse models. We analyzed the pathological conditions of the intestine and liver on histological, cellular, and molecular levels. We observed bacterial translocation and an influx of inflammatory cells, in particular Th17 cells, to the liver during colitis. In the DSS colitis model, in which Treg were concomitantly increased in the liver, we did not observe an overt pathological condition of the liver. In contrast, the T cell-mediated colitis model, in which Treg are not abundant, was associated with marked liver inflammation and a pathological condition. Of note, upon depletion of Treg in DEREG mice, DSS colitis promotes accumulation of Th17 cells and a pathological condition of the liver. Finally, we studied immune cell migration using KAEDE mice and found that some of these cells had migrated directly from the inflamed intestine into the liver. Overall, these data indicate that colitis can promote a pathological condition of the liver and highlight an important role of Treg in controlling colitis-associated liver inflammation.