Gut dysbiosis during influenza contributes to pulmonary pneumococcal superinfection through altered short-chain fatty acid production

Secondary bacterial infections often complicate viral respiratory infections. We hypothesize that perturbation of the gut microbiota during influenza A virus (IAV) infection might favor respiratory bacterial superinfection. Sublethal infection with influenza transiently alters the composition and fermentative activity of the gut microbiota in mice. These changes are attributed in part to reduced food consumption. Fecal transfer experiments demonstrate that the IAV-conditioned microbiota compromises lung defenses against pneumococcal infection. In mechanistic terms, reduced production of the predominant short-chain fatty acid (SCFA) acetate affects the bactericidal activity of alveolar macrophages. Following treatment with acetate, mice colonized with the IAV-conditioned microbiota display reduced bacterial loads. In the context of influenza infection, acetate supplementation reduces, in a free fatty acid receptor 2 (FFAR2)-dependent manner, local and systemic bacterial loads. This translates into reduced lung pathology and improved survival rates of double-infected mice. Lastly, pharmacological activation of the SCFA receptor FFAR2 during influenza reduces bacterial superinfection

Microbiota, dieta e sistema imune: um diálogo constante via ativação do receptor acoplado à proteína-G 43 (Gpr43)

Exportado OPUSMade available in DSpace on 2019-08-11T14:05:24Z (GMT). No. of bitstreams: 1 tese_angelica_t_vieira.pdf: 10253941 bytes, checksum: be04c3a96a569ad2ff3cb57984a5d84b (MD5) Previous issue date: 10As bactérias comensais do trato gastrointestinal modulam o desenvolvimento do sistema imune. A microbiota intestinal produz fatores que são benéficos pois regulam a resposta imune do hospedeiro. Um desses fatores são os short-chain fatty acids (SCFA) do português: ácidos graxos de cadeia curta, que são produzidos pela fermentação de fibras solúveis da dieta pela microbiota saudável, tais quais os gêneros Bifidobacterium e Bacteroides. Os SCFAs se ligam ao receptor acoplado à proteína G-43 (GPR43), também conhecido como FFAR2), e nesse trabalho demonstramos que a interação SCFAGPR43 exerce efeitos modulatórios nas respostas inflamatórias. A estimulação do GPR43 pelo SCFA é necessária para a resolução da resposta inflamatória. Animais deficientes de GPR43 (Gpr43-/-) mostraram uma exacerbada e não-resolutiva inflamação tanto no modelo de colite, quanto nos modelos de artrite e asma. Interessantemente, os animais Gpr43-/- apresentaram uma resposta ineficiente a gota devido à inabilidade em ativar o complexo inflamassoma. Entretanto, o tratamento com acetato (o mais abundante SCFA) antes e depois da indução da gota nos animais selvagens, aboliu o dano tecidual, promovendo a resolução da resposta induzida pela gota. Além disso, animais alimentados com dieta rica em fibras ou com o próbiotico Bifidobacterium longum apresentaram uma redução do infiltrado celular nos animais desafiados com monossódio de urato (MSU). Animais germ-free (GF), que não possuem bactérias e, desse modo, não produzem SCFAs, mostraram uma resposta similar aos animais Gpr43-/-. Animais GF apresentaram uma resposta exacerbada na colite, na asma, e na artrite reumatóide. No entanto, se tratarmos previamente os animais GF com acetato, observamos uma resposta inflamatória reduzida nesses modelos. Além disso, animais GF desafiados com MSU apresentaram uma hiporresponsividade similar ao Gpr43- /- com reduzido recrutamento celular. Entretanto, tratamento prévio com acetato reverteu esta hiporresponsividade. Assim, esses dados sugerem a habilidade do acetato em primar o sistema imune permitindo o recrutamento de células durante a resposta induzida por MSU. Em resumo, esse trabalho sugere que a microbiota modula a habilidade do hospedeiro em responder aos estímulos inflamatórios e, a interação entre SCFA-GPR43 representa um mecanismo central entre dieta, microbiota e resposta imune, provendo um importante link entre eles.The commensal bacterial of the gastrointestinal tract shapes the development of the immune system. The gut microbiota produces factors that are beneficial to the host for the regulation of immune responses. One of these factors may be the shortchain fatty acids (SCFA), which are produced by fermentation of dietary fiber by healthy microbiota such as Bifidobacterium and Bacteroides. SCFAs bind to Gprotein coupled receptor 43 (GPR43, also known as FFAR2), and in this work we show that SCFAGPR43 interactions exerts modulator effects in inflammatory responses. Stimulation of GPR43 by SCFA was necessary for the resolution of inflammatory responses. GPR43-deficient (Gpr43-/-) mice showed exacerbated or unresolving inflammation in models of colitis, arthritis and asthma. Interestingly, the Gpr43-/- mice showed impair response to gout by the inability to activate inflammasoma complex. However, acetate treatment before and after gout induction in wt mice abolished tissue injury promoting resolution of the inflammation. Furthermore, mice fed with higher fiber diet or with Bifidobacterium longum reduced cells infiltrate in mice challenged with MSU. Germ-free mice (GF), which are devoid of bacteria and no or little SCFAs production, showed a similar response to Gpr43-/- mice. GF mice showed an exacerbated response in colitis, asthma and rheumatoid arthritis models. However, if we treated GF with acetate (the most abundant SCFA) before such diseases, a protective effect was observed. Furthermore, GF mice MSU challenged showed a similar hiporresponsive and inhibited recruitment of cells when compared to Gpr43-/- mice. Although, when we treated GF with acetate before challenged with MSU this phenotype was reversed. Thus, these data suggested an ability of acetate to prime the immune system and allow inflammatory cell recruitment during response to MSU challenge. In summary, this work suggests that endogenous microbiota shapes the hosts ability to respond to inflammatory stimuli and SCFA-GPR43 interactions could represent a central mechanism to account for affects of diet and gut microbiota on immune responses providing a molecular link between diet, gastrointestinal bacterial metabolism and inflammatory responses

The role of probiotics and prebiotics inducing gut immunity

The gut immune system is influenced by many factors, including dietary components and commensal bacteria. Nutrients that affect gut immunity and strategies that restore a healthy gut microbial community by affecting the microbial composition are being developed as new therapeutic approaches to treat several inflammatory diseases. Although probiotics (live microorganisms) and prebiotics (food components) have shown promise as treatments for several diseases in both clinical and animal studies, an understanding of the molecular mechanisms behind the direct and indirect effects on the gut immune response will facilitate better and possibly more efficient therapy for diseases. In this review, we will first describe the concept of prebiotics, probiotics and symbiotics and cover the most recently well-established scientific findings regarding the direct and indirect mechanisms by which these dietary approaches can influence gut immunity. Emphasis will be placed on the relationship of diet, the microbiota and the gut immune system. Second, we will highlight recent results from our group, which suggest a new dietary manipulation that includes the use of nutrient products (organic selenium and Lithothamnium muelleri) and probiotics (Saccharomyces boulardii UFMG 905 and Bifidobacterium sp.) that can stimulate and manipulate the gut immune response, inducing intestinal homeostasis. Furthermore, the purpose of this review is to discuss and translate all of this knowledge into therapeutic strategies and into treatment for extra-intestinal compartment pathologies. We will conclude by discussing perspectives and molecular advances regarding the use of prebiotics or probiotics as new therapeutic strategies that manipulate the microbial composition and the gut immune responses of the host

Fungal footprints in oral cancer: unveiling the oral mycobiome

Oral squamous cell carcinoma (OSCC) is the most common type of head and neck cancer, with a high mortality rate. There is growing evidence supporting a link between oral cancer and the microbiome. The microbiome can impact various aspects of cancer, such as pathogenesis, diagnosis, treatment, and prognosis. While there is existing information on bacteria and its connection to oral cancer, the fungi residing in the oral cavity represent a significant component of the microbiome that remains in its early stages of exploration and understanding. Fungi comprise a minuscule part of the human microbiome called the mycobiome. Mycobiome is ubiquitous in the human body but a weakened immune system offers a leeway space for fungi to showcase its virulence. The role of mycobiome as a colonizer, facilitator, or driver of carcinogenesis is still ambiguous. Reactivating the mycobiome that undergoes collateral damage associated with cancer treatment can be watershed event in cancer research. The coordinated, virulent, non-virulent behavior of the fungi once they reach a critical density must be hacked, considering its diagnostic, prognostic and therapeutic implications in cancer. This review highlights the diversity of the mycobiome and its potential role in oral cancer

Caracterização da fusão caruncular em gestações naturais e de conceptos bovinos clonados

Barreto R.S.N., Miglino M.A., Meirelles F.V., Visintin J.A., Silva S.M., Burioli K.C., Fonseca R., Bertan C., Assis Neto A.C. & Pereira F.T.V. 2009. [Characterization of the caruncular fusion in gestations of natural and cloned bovine conceptuses.] Caracterizacao da fusao caruncular ern gestacoes naturais e de conceptos bovinos clonados. Pesquisa Veterinaria Brasileira 29(10):779-787. Laboratorio de Morfofisiologia da Placenta e Embriao, Faculdade de Zootecnia, Universidade Estadual Paulista, SP294 Km 651, Dracena, SP 17900-000, Brazil. E-mail: [email protected] objective of the study was to compare the characteristics of the caruncular fusion in gestations of non-cloned and cloned conceptuses. The non-cloned conceptuses were divided according to the gestation period: Group 1 (2 to 3 months; n=9),II (4 to 6; n=9); III (7 to 8; n=10) and IV (9 n=7). The cloned conceptuses formed the Group V: 9 months; n=4. The caruncles were observed macroscopically (number and dimensions: length, width and height), microscopically and submitted to statistical analysis (5% of significance). We observed three types of macroscopic caruncular fusions: oval (morphologically normal); two united adjacent caruncles and the lobulated type, characterized by regions with several united caruncles presenting a false fusion or deformation of the caruncular parenchyma. The length of the caruncles was 1.55 +/- 0.57; 2.45 +/- 0.55; 4.66 +/- 2.0 and 5.72 +/- 1.90cm for the groups 1, 11, 111, IV respectively. As for the height, the caruncles presented a lineal growth during the gestation: 0.40 +/- 0.15; 0.57 +/- 0.21; 1.0 +/- 0.48 and 1.80 +/- 0.91cm, for the respective groups 1, 11, 111 and IV. The width of the caruncles was similar between the groups I and 11 (0.97 +/- 0.30 e 1.42 +/- 0.71 cm) and the groups III and IV (2.68 +/- 1.22 and 3.52 +/- 1.16cm). When the group V was compared to the IV, the caruncles of the group V presented a larger length (5.72 +/- 1.90 vs. 7.88 +/-.13cm) and width (3.52 +/- 1.16 vs. 4.93 +/- 1.46cm), however they were similar in height (1.80 +/- 0.91 and 2.25 +/- 0.67cm). We verified that in gestations of cloned conceptuses the caruncles presented a larger development than in gestations of non-cloned conceptuses. The fusioned caruncles presented measurements statistically similar to the isolated ones in all the parameters and groups. Under light microscopy, we observed the formation of a stromal axis from the basis of the caruncle to the apex of the fusional fissure, with the histological constitution similar to the endometrial stroma. Three microscopic shapes were also unpublished defined: true fusion with a single axis evident below the fusional fissure; pseudofusion with a double axis in H shape and false fusion with absence of the axis. The first two formats were associated to the oval and lobulated caruncles and the last one to the false fusion with deformation of the caruncle parenchyma. The fusional axis increased in size along the gestation among the groups I, II, III and IV. The group V presented a larger length and width of the axis when compared to the group IV. Thus, in gestations of cloned conceptuses a destruction of the lateral epithelium of the caruncles is associated to an incompetence in the maternal-fetal interdigitation, that compromises the cotyledonary fusion. We suggest that, in gestations derived of cloned conceptuses, the increase of the size of the caruncular fusions is possibly associated to a compensatory mechanism for the metabolic exchanges between mother and fetus, in reason of the smallest number of isolated caruncles

Fetal-Maternal Interactions in the Synepitheliochorial Placenta Using the eGFP Cloned Cattle Model

Background: To investigate mechanisms of fetal-maternal cell interactions in the bovine placenta, we developed a model of transgenic enhanced Green Fluorescent Protein (t-eGFP) expressing bovine embryos produced by nuclear transfer (NT) to assess the distribution of fetal-derived products in the bovine placenta. In addition, we searched for male specific DNA in the blood of females carrying in vitro produced male embryos. Our hypothesis is that the bovine placenta is more permeable to fetal-derived products than described elsewhere. Methodology/Principal Findings: Samples of placentomes, chorion, endometrium, maternal peripheral blood leukocytes and blood plasma were collected during early gestation and processed for nested-PCR for eGFP and testis-specific Y-encoded protein (TSPY), western blotting and immunohistochemistry for eGFP detection, as well as transmission electron microscopy to verify the level of interaction between maternal and fetal cells. TSPY and eGFP DNA were present in the blood of cows carrying male pregnancies at day 60 of pregnancy. Protein and mRNA of eGFP were observed in the trophoblast and uterine tissues. In the placentomes, the protein expression was weak in the syncytial regions, but intense in neighboring cells on both sides of the fetal-maternal interface. Ultrastructurally, our samples from t-eGFP expressing NT pregnancies showed to be normal, such as the presence of interdigitating structures between fetal and maternal cells. In addition, channels-like structures were present in the trophoblast cells. Conclusions/Significance: Data suggested that there is a delivery of fetal contents to the maternal system on both systemic and local levels that involved nuclear acids and proteins. It not clear the mechanisms involved in the transfer of fetal-derived molecules to the maternal system. This delivery may occur through nonclassical protein secretion; throughout transtrophoblastic-like channels and/or by apoptotic processes previously described. In conclusion, the bovine synepitheliochorial placenta displays an intimate fetal-maternal interaction, similar to other placental types for instance human and mouse. © 2013 Pereira et al

Enhanced green fluorescent protein (eGFP) expression at the fetal-maternal interface of the eGFP transgenic cloned bovine embryo at day 90.

<p>Please note (arrow) that the trophoblastic cells that are close to the maternal cells displays weak staining for eGFP. Fetal mesenchyme (FM); endometrial epithelium (EE); maternal stroma (MS) and villous area (VA).</p

Detection of eGFP protein in fetal and maternal tissues from eGFP transgenic cloned placenta.

<p>Western blotting analysis to detect eGFP protein in 1: transgenic eGFP fetal chorion; 2: transgenic eGFP placentome; 3: molecular marker and 4: intercaruncular endometrium from pregnant horn eGFP from transgenic placenta.</p

Expression of eGFP in fetal and maternal tissues from eGFP transgenic cloned placenta.

<p>Mean of relative expression of eGFP mRNA in the intercaruncular chorion (black bar), placentome (dark grey bar) and intercaruncular endometrium (light grey bar).</p

Primer/Probe sets used for qRT-PCR.

a<p>Forward =  sense (5′) primer.</p>b<p>Each probe was synthesized 6-FAM reporter dye and TAMRA quencher.</p>c<p>Reverse =  antisense (3′) primer.</p