RESUMO
Gasdermins are a family of structurally related proteins originally described for their role in pyroptosis. Gasdermin B (GSDMB) is currently the least studied, and while its association with genetic susceptibility to chronic mucosal inflammatory disorders is well established, little is known about its functional relevance during active disease states. Herein, we report increased GSDMB in inflammatory bowel disease, with single-cell analysis identifying epithelial specificity to inflamed colonocytes/crypt top colonocytes. Surprisingly, mechanistic experiments and transcriptome profiling reveal lack of inherent GSDMB-dependent pyroptosis in activated epithelial cells and organoids but instead point to increased proliferation and migration during in vitro wound closure, which arrests in GSDMB-deficient cells that display hyper-adhesiveness and enhanced formation of vinculin-based focal adhesions dependent on PDGF-A-mediated FAK phosphorylation. Importantly, carriage of disease-associated GSDMB SNPs confers functional defects, disrupting epithelial restitution/repair, which, altogether, establishes GSDMB as a critical factor for restoration of epithelial barrier function and the resolution of inflammation.
Assuntos
Células Epiteliais/metabolismo , Células Epiteliais/patologia , Doenças Inflamatórias Intestinais/metabolismo , Doenças Inflamatórias Intestinais/patologia , Proteínas Citotóxicas Formadoras de Poros/metabolismo , Piroptose , Sequência de Bases , Estudos de Casos e Controles , Adesão Celular/efeitos dos fármacos , Adesão Celular/genética , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Movimento Celular/efeitos dos fármacos , Movimento Celular/genética , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/genética , Células Epiteliais/efeitos dos fármacos , Proteína-Tirosina Quinases de Adesão Focal/metabolismo , Células HEK293 , Células HT29 , Humanos , Doenças Inflamatórias Intestinais/genética , Metotrexato/farmacologia , Mutação/genética , Fosforilação/efeitos dos fármacos , Polimorfismo de Nucleotídeo Único/genética , Piroptose/efeitos dos fármacos , Piroptose/genética , Reprodutibilidade dos Testes , Transcriptoma/efeitos dos fármacos , Transcriptoma/genética , Regulação para Cima/efeitos dos fármacos , Cicatrização/efeitos dos fármacos , Cicatrização/genéticaRESUMO
Crohn's disease and ulcerative colitis are chronic and progressive inflammatory bowel diseases (IBDs) that are attributed to dysregulated interactions between the gut microbiome and the intestinal mucosa-associated immune system. There are limited studies investigating the role of either IL-1α or IL-1ß in mouse models of colitis, and no clinical trials blocking either IL-1 have yet to be performed. In the present study, we show that neutralization of IL-1α by a specific monoclonal antibody against murine IL-1α was highly effective in reducing inflammation and damage in SAMP mice, mice that spontaneously develop a Crohn's-like ileitis. Anti-mouse IL-1α significantly ameliorated the established, chronic ileitis and also protected mice from developing acute DSS-induced colitis. Both were associated with taxonomic divergence of the fecal gut microbiome, which was treatment-specific and not dependent on inflammation. Anti-IL-1α administration led to a decreased ratio of Proteobacteria to Bacteroidetes, decreased presence of Helicobacter species, and elevated representation of Mucispirillum schaedleri and Lactobacillus salivarius. Such modification in flora was functionally linked to the antiinflammatory effects of IL-1α neutralization, as blockade of IL-1α was not effective in germfree SAMP mice. Furthermore, preemptive dexamethasone treatment of DSS-challenged SAMP mice led to changes in flora composition without preventing the development of colitis. Thus, neutralization of IL-1α changes specific bacterial species of the intestinal microbiome, which is linked to its antiinflammatory effects. These functional findings may be of significant value for patients with IBD, who may benefit from targeted IL-1α-based therapies.
RESUMO
Nucleotide-binding oligomerization domain-containing 2 (NOD2) is an intracellular receptor that plays an essential role in innate immunity as a sensor of a component of the bacterial cell wall, muramyl dipeptide (MDP). Crohn's disease (CD)-associated NOD2 variants lead to defective innate immune responses, including decreased NF-κB activation and cytokine production. We report herein that SAMP1/YitFc (SAMP) mice, which develop spontaneous CD-like ileitis in the absence of NOD2 genetic mutations, fail to respond to MDP administration by displaying decreased innate cytokine production and dysregulated NOD2 signaling compared with parental AKR control mice. We show that, unlike in other mouse strains, in vivo administration of MDP does not prevent dextran sodium sulfate-induced colitis in SAMP mice and that the abnormal NOD2 response is specific to the hematopoietic cellular component. Moreover, we demonstrate that MDP fails to enhance intracellular bacterial killing in SAMP mice. These findings shed important light on the initiating molecular events underlying CD-like ileitis.
Assuntos
Predisposição Genética para Doença , Células-Tronco Hematopoéticas/imunologia , Ileíte/imunologia , Imunidade Inata , Proteína Adaptadora de Sinalização NOD2/imunologia , Animais , Doença de Crohn/genética , Doença de Crohn/imunologia , Doença de Crohn/patologia , Citocinas/genética , Citocinas/imunologia , Células-Tronco Hematopoéticas/patologia , Ileíte/induzido quimicamente , Ileíte/genética , Ileíte/patologia , Camundongos Endogâmicos AKR , Camundongos Transgênicos , Proteína Adaptadora de Sinalização NOD2/genéticaRESUMO
Inflammatory bowel disease (IBD) is an umbrella term for two conditions (Crohn's Disease and Ulcerative Colitis) that is characterized by chronic inflammation of the gastrointestinal tract. The use of pre-clinical animal models has been invaluable for the understanding of potential disease mechanisms. However, despite promising results of numerous therapeutics in mouse colitis models, many of these therapies did not show clinical benefits in patients with IBD. Single cell RNA-sequencing (scRNA-seq) has recently revolutionized our understanding of complex interactions between the immune system, stromal cells, and epithelial cells by mapping novel cell subpopulations and their remodeling during disease. This technology has not been widely applied to pre-clinical models of IBD. ScRNA-seq profiling of murine models may provide an opportunity to increase the translatability into the clinic, and to choose the most appropriate model to test hypotheses and novel therapeutics. In this review, we have summarized some of the key findings at the single cell transcriptomic level in IBD, how specific signatures have been functionally validated in vivo, and highlighted the similarities and differences between scRNA-seq findings in human IBD and experimental mouse models. In each section of this review, we highlight the importance of utilizing this technology to find the most suitable or translational models of IBD based on the cellular therapeutic target.
Assuntos
Colite Ulcerativa , Colite , Doença de Crohn , Doenças Inflamatórias Intestinais , Humanos , Animais , Camundongos , Doenças Inflamatórias Intestinais/terapia , Doenças Inflamatórias Intestinais/tratamento farmacológico , RNARESUMO
In addition to their well-known role in acute injury and chronic inflammation, "innate" cytokines play an important role in health and the maintenance of normal immune homeostasis. This group includes the prototypic cytokines IL-1 and TNFα, as well as several other members belonging to the IL-1 and TNF family, such as IL-18, IL-33, IL-36-38, and TL1A. The dichotomous role of these cytokines has been best characterized in the intestine where innate cytokines may play both a protective and a pro-inflammatory role, depending upon the immmunological status of the host or the type and phase of the inflammatory process. This new information has produced novel pathogenetic hypotheses that have important translational implications both in regard to the prevention and treatment of chronic intestinal inflammation, including Crohn's disease and ulcerative colitis, the two major forms of inflammatory bowel disease. This review will discuss and summarize current data regarding the role of IL-1, TNFα, and their family members in regulating gut mucosal homeostasis and chronic intestinal inflammation.
Assuntos
Citocinas/imunologia , Citocinas/metabolismo , Trato Gastrointestinal/imunologia , Trato Gastrointestinal/patologia , Homeostase/imunologia , Inflamação/imunologia , Inflamação/patologia , Animais , Predisposição Genética para Doença , Humanos , Inflamação/genética , Mucosa Intestinal/imunologia , Mucosa Intestinal/patologiaRESUMO
Innate lymphoid cells (ILCs) are enriched at barrier surfaces, including the gastrointestinal tract. While most studies have focused on the balance between pathogenic group 1 ILCs (ILC1s) and protective ILC3s in maintaining gut homeostasis and during chronic intestinal inflammation, such as Crohn's disease (CD), less is known regarding ILC2s. Using an established murine model of CD-like ileitis, i.e., the SAMP1/YitFc (SAMP) mouse strain, we showed that ILC2s, compared with ILC1s and ILC3s, were increased within draining mesenteric lymph nodes and ilea of SAMP versus AKR (parental control) mice early, during the onset of disease. Gut-derived ILC2s from CD patients versus healthy controls were also increased and expanded, similarly to ILC1s, in greater proportion compared with ILC3s. Importantly, we report that the intracellular bacteria-sensing protein, nucleotide-binding oligomerization domaining-containing protein 2, encoded by Nod2, the first and strongest susceptibility gene identified for CD, promoted ILC2 expansion, which was dramatically reduced in SAMP mice lacking NOD2 and in SAMP mice raised under germ-free conditions. Furthermore, these effects occurred through a mechanism involving the IL-33/ST2 ligand-receptor pair. Collectively, our results indicate a functional link between NOD2 and ILC2s, regulated by the IL-33/ST2 axis, that mechanistically may contribute to early events leading to CD pathogenesis.
Assuntos
Doença de Crohn/imunologia , Ileíte/imunologia , Interleucina-33/imunologia , Linfócitos/imunologia , Proteína Adaptadora de Sinalização NOD2/imunologia , Transdução de Sinais/imunologia , Animais , Doença de Crohn/genética , Doença de Crohn/patologia , Modelos Animais de Doenças , Ileíte/genética , Ileíte/patologia , Interleucina-33/genética , Linfócitos/patologia , Camundongos , Proteína Adaptadora de Sinalização NOD2/genética , Transdução de Sinais/genéticaRESUMO
Cutaneous group 2 innate lymphoid cells (ILC2) are spatially and epigenetically poised to respond to barrier compromise and associated immunological threats. ILC2, lacking rearranged antigen-specific receptors, are primarily activated by damage-associated cytokines and respond with type 2 cytokine production. To investigate ILC2 potential for direct sensing of skin pathogens and allergens, we performed RNA sequencing of ILC2 derived from in vivo challenged human skin or blood. We detected expression of NOD2 and TLR2 by skin and blood ILC2. Stimulation of ILC2 with TLR2 agonist alone not only induced interleukin-5 (IL-5) and IL-13 expression but also elicited IL-6 expression in combination with Staphylococcus aureus muramyl dipeptide (MDP). Heat-killed skin-resident bacteria provoked an IL-6 profile in ILC2 in vitro that was notably impaired in ILC2 derived from patients with nucleotide-binding oligomerization domain-containing protein 2 (NOD2) mutations. In addition, we show that NOD2 signaling can stimulate autophagy in ILC2, which was also impaired in patients with NOD2 mutations. Here, we have identified a role for ILC2 NOD2 signaling in the differential regulation of ILC2-derived IL-6 and have reported a previously unrecognized pathway of direct ILC2 bacterial sensing.
Assuntos
Citocinas/imunologia , Linfócitos/imunologia , Proteína Adaptadora de Sinalização NOD2/imunologia , Infecções Estafilocócicas/imunologia , Adulto , Alérgenos/imunologia , Antígenos de Dermatophagoides/imunologia , Humanos , Imunidade Inata , Mutação , Proteína Adaptadora de Sinalização NOD2/genética , Pele/imunologia , Pele/microbiologia , Staphylococcus aureus , Receptor 2 Toll-Like/imunologiaRESUMO
The intestinal mucosa represents a unique environment where the coordinated function of diverse epithelial, mesenchymal, and immune cells maintains a physiologically balanced environment in the presence of gut microbiota. The intestinal mucosa plays a central role in the pathogenesis of inflammatory bowel disease (IBD), yet the molecular and cellular composition of this diverse environment is poorly understood. However, the recent advent of multimodal single-cell technologies, including single-cell RNA sequencing (scRNA-seq), now provides an opportunity to accurately map the tissue architecture, characterize rare cell types that were previously overlooked, and define function at a single-cell level. In this review, we summarize key advances in single-cell technology and provide an overview of important aspects of computational analysis. We describe emerging data in the field of IBD and discuss how the characterization of novel intestinal mucosa cell populations is reshaping our understanding of this complex disease. We conclude by considering the potential clinical applications, including the definition of novel drug targets and the opportunity for personalization of care in this exciting new era of precision medicine.
Assuntos
Doenças Inflamatórias Intestinais/genética , Ciência de Laboratório Médico/tendências , RNA-Seq/tendências , Análise de Célula Única/tendências , Humanos , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologiaRESUMO
Colonic antigen-experienced lymphocytes such as tissue-resident memory CD8+ T cells can respond rapidly to repeated antigen exposure. However, their cellular phenotypes and the mechanisms by which they drive immune regulation and inflammation remain unclear. Here we compiled an unbiased atlas of human colonic CD8+ T cells in health and ulcerative colitis (UC) using single-cell transcriptomics with T-cell receptor repertoire analysis and mass cytometry. We reveal extensive heterogeneity in CD8+ T-cell composition, including expanded effector and post-effector terminally differentiated CD8+ T cells. While UC-associated CD8+ effector T cells can trigger tissue destruction and produce tumor necrosis factor (TNF)-α, post-effector cells acquire innate signatures to adopt regulatory functions that may mitigate excessive inflammation. Thus, we identify colonic CD8+ T-cell phenotypes in health and UC, define their clonal relationships and characterize terminally differentiated dysfunctional UC CD8+ T cells expressing IL-26, which attenuate acute colitis in a humanized IL-26 transgenic mouse model.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Colite Ulcerativa/patologia , Interleucinas/metabolismo , Mucosa Intestinal/patologia , Fator de Necrose Tumoral alfa/metabolismo , Animais , Colo/patologia , Feminino , Perfilação da Expressão Gênica , Humanos , Mucosa Intestinal/citologia , Mucosa Intestinal/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Transcriptoma/genéticaRESUMO
Gasdermin D (GSDMD) induces pyroptosis via the pore-forming activity of its N-terminal domain, cleaved by activated caspases associated with the release of IL-1ß. Here, we report a nonpyroptotic role of full-length GSDMD in guiding the release of IL-1ß-containing small extracellular vesicles (sEVs) from intestinal epithelial cells (IECs). In response to caspase-8 inflammasome activation, GSDMD, chaperoned by Cdc37/Hsp90, recruits the E3 ligase, NEDD4, to catalyze polyubiquitination of pro-IL-1ß, serving as a signal for cargo loading into secretory vesicles. GSDMD and IL-1ß colocalize with the exosome markers CD63 and ALIX intracellularly, and GSDMD and NEDD4 are required for release of CD63+ sEVs containing IL-1ß, GSDMD, NEDD4, and caspase-8. Importantly, increased expression of epithelial-derived GSDMD is observed both in patients with inflammatory bowel disease (IBD) and those with experimental colitis. While GSDMD-dependent release of IL-1ß-containing sEVs is detected in cultured colonic explants from colitic mice, GSDMD deficiency substantially attenuates disease severity, implicating GSDMD-mediated release of IL-1ß sEVs in the pathogenesis of intestinal inflammation, such as that observed in IBD.
Assuntos
Colite/metabolismo , Células Epiteliais/metabolismo , Doenças Inflamatórias Intestinais/metabolismo , Interleucina-1beta/metabolismo , Mucosa Intestinal/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas de Ligação a Fosfato/metabolismo , Animais , Linhagem Celular , Colite/genética , Colite/patologia , Células Epiteliais/patologia , Exossomos/genética , Exossomos/metabolismo , Exossomos/patologia , Vesículas Extracelulares/genética , Vesículas Extracelulares/metabolismo , Vesículas Extracelulares/patologia , Doenças Inflamatórias Intestinais/genética , Doenças Inflamatórias Intestinais/patologia , Interleucina-1beta/genética , Mucosa Intestinal/patologia , Peptídeos e Proteínas de Sinalização Intracelular/genética , Camundongos , Camundongos Knockout , Ubiquitina-Proteína Ligases Nedd4/genética , Ubiquitina-Proteína Ligases Nedd4/metabolismo , Proteínas de Ligação a Fosfato/genética , Tetraspanina 30/genética , Tetraspanina 30/metabolismoRESUMO
A critical role of pattern recognition receptors (PRRs) is to influence adaptive immune responses by regulating antigen presentation. Engagement of PRRs in dendritic cells (DCs) increases MHC class I antigen presentation and CD8+ T-cell activation by cross-presented peptides but the molecular mechanisms underlying these effects are not completely understood. Studies looking at the role of PRRs in cross-presentation have been largely limited to TLRs but the role of other PRRs such as cytosolic nucleotide-binding oligomerization domain-like (NOD-like) receptors remains particularly enigmatic. Here we discuss recent evidence of the role of PRRs on cross-presentation and consider how cytosolic NLR-associated pathways, such as NOD2, may integrate these signals resulting in effective adaptive CD8+ T cells responses.
Assuntos
Apresentação Cruzada/imunologia , Imunidade Inata/imunologia , Proteínas NLR/imunologia , Animais , Linfócitos T CD8-Positivos , Humanos , Receptores de Reconhecimento de Padrão/imunologia , Transdução de Sinais/imunologiaRESUMO
NOD2 and TLR2 recognize components of bacterial cell wall peptidoglycan and direct defense against enteric pathogens. CD8+ T cells are important for immunity to such pathogens but how NOD2 and TLR2 induce antigen specific CD8+ T cell responses is unknown. Here, we define how these pattern recognition receptors (PRRs) signal in primary dendritic cells (DCs) to influence MHC class I antigen presentation. We show NOD2 and TLR2 phosphorylate PI31 via TBK1 following activation in DCs. PI31 interacts with TBK1 and Sec16A at endoplasmic reticulum exit sites (ERES), which positively regulates MHC class I peptide loading and immunoproteasome stability. Following NOD2 and TLR2 stimulation, depletion of PI31 or inhibition of TBK1 activity in vivo impairs DC cross-presentation and CD8+ T cell activation. DCs from Crohn's patients expressing NOD2 polymorphisms show dysregulated cross-presentation and CD8+ T cell responses. Our findings reveal unidentified mechanisms that underlie CD8+ T cell responses to bacteria in health and in Crohn's.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Apresentação Cruzada , Células Dendríticas/imunologia , Proteína Adaptadora de Sinalização NOD2/imunologia , Complexo de Endopeptidases do Proteassoma/imunologia , Proteínas Serina-Treonina Quinases/imunologia , Receptor 2 Toll-Like/imunologia , Antígenos de Bactérias/imunologia , Doença de Crohn/imunologia , Retículo Endoplasmático/imunologia , Antígenos de Histocompatibilidade Classe I/imunologia , Humanos , Fosforilação/imunologia , Proteínas de Transporte Vesicular/imunologiaRESUMO
The interplay between NOD2 and TLR2 following recognition of components of the bacterial cell wall peptidoglycan is well-established, however their role in redirecting metabolic pathways in myeloid cells to degrade pathogens and mount antigen presentation remains unclear. We show NOD2 and TLR2 mediate phosphorylation of the deubiquitinase ataxin-3 via RIPK2 and TBK1. In myeloid cells ataxin-3 associates with the mitochondrial cristae protein MIC60, and is required for oxidative phosphorylation. Depletion of ataxin-3 leads to impaired induction of mitochondrial reactive oxygen species (mROS) and defective bacterial killing. A mass spectrometry analysis of NOD2/TLR2 triggered ataxin-3 deubiquitination targets revealed immunometabolic regulators, including HIF-1α and LAMTOR1 that may contribute to these effects. Thus, we define how ataxin-3 plays an essential role in NOD2 and TLR2 sensing and effector functions in myeloid cells.
Assuntos
Ataxina-3/imunologia , Células Mieloides/imunologia , Células Mieloides/metabolismo , Proteína Adaptadora de Sinalização NOD2/imunologia , Proteína Serina-Treonina Quinase 2 de Interação com Receptor/imunologia , Receptor 2 Toll-Like/imunologia , Ataxina-3/metabolismo , Respiração Celular , Células HEK293 , Humanos , Imunidade Inata , Mitocôndrias/metabolismo , Proteína Adaptadora de Sinalização NOD2/metabolismo , Fosforilação , Proteínas Serina-Treonina Quinases/imunologia , Proteínas Serina-Treonina Quinases/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Proteína Serina-Treonina Quinase 2 de Interação com Receptor/metabolismo , Transdução de Sinais , Células THP-1 , Receptor 2 Toll-Like/metabolismoRESUMO
The advent of single-cell technologies has revolutionized analyses of IBD-specific processes by identifying important, often novel, mucosal cells subpopulations and their associated functions. We discuss recent findings reporting transcriptomic and cellular diversity of treatment-naïve and treated patients with ileal-specific CD.
Assuntos
Doença de Crohn , Humanos , Doença de Crohn/genética , Transcriptoma , Íleo , Células Epiteliais , MucosaRESUMO
Activation of the innate immune system through pattern-recognition receptor (PRR) signaling plays a pivotal role in the early induction of host defense following exposure to pathogens. Loss of intestinal innate immune regulation leading aberrant immune responses has been implicated in the pathogenesis of inflammatory bowel disease (IBD). The precise role of PRRs in gut inflammation is not well understood, but considering their role as bacterial sensors and their genetic association with IBD, they likely contribute to dysregulated immune responses to the commensal microbiota. The purpose of this review is to evaluate the emerging functions of PRRs including their functional cross-talk, how they respond to mitochondrial damage, induce mitophagy or autophagy, and influence adaptive immune responses by interacting with the antigen presentation machinery. The review also summarizes some of the recent attempts to harness these pathways for therapeutic approaches in intestinal inflammation.
RESUMO
Patients with inflammatory bowel disease (IBD) are at increased risk for developing colorectal cancer. Evidence suggests that colonic dysplasia and colitis-associated cancer (CAC) are often linked to repeated cycles of epithelial cell injury and repair in the context of chronic production of inflammatory cytokines. Several mouse models of CAC have been proposed, including chemical induction through exposure to dextran sulfate sodium (DSS) with the genotoxic agents azoxymethane (AOM), 1,2-dymethylhydrazine (DHM) or targeted genetic mutations. However, such models are usually performed on healthy animals that usually lack the underlying genetic predisposition, immunological dysfunction and dysbiosis characteristic of IBD. We have previously shown that inbred SAMP1/YitFc (SAMP) mice develop a progressive Crohn's disease (CD)-like ileitis in the absence of spontaneous colitis. We hypothesize that SAMP mice may be more susceptible to colonic tumorigenesis due to their predisposition to IBD. To test this hypothesis, we administered AOM/DSS to IBD-prone SAMP and their non-inflamed parental control strain, AKR mice. Our results showed that AOM/DSS treatment enhanced the susceptibility of colitis in SAMP compared to AKR mice, as assessed by endoscopic and histologic inflammatory scores, daily weight loss and disease activity index (DAI), during and after DSS administration. SAMP mice also showed increased colonic tumorigenesis, resulting in the occurrence of intramucosal carcinoma and a higher incidence of high-grade dysplasia and tumor burden. These phenomena occurred even in the absence of AOM and only upon repeated cycles of DSS. Taken together, our data demonstrate a heightened susceptibility to colonic inflammation and tumorigenesis in AOM/DSS-treated SAMP mice with CD-like ileitis. This novel model represents a useful tool to investigate relevant mechanisms of CAC, as well as for pre-clinical testing of potential IBD and colon cancer therapeutics.
Assuntos
Neoplasias do Colo/etiologia , Doença de Crohn/complicações , Modelos Animais de Doenças , Ileíte/complicações , Proteínas de Membrana/genética , Proteínas Nucleares/genética , Animais , Neoplasias do Colo/genética , Doença de Crohn/genética , Ileíte/genética , CamundongosRESUMO
Histology is fundamental to assess two-dimensional intestinal inflammation; however, inflammatory bowel diseases (IBDs) are often indistinguishable microscopically on the basis of mucosal biopsies. Here, we use stereomicroscopy (SM) to rapidly profile the entire intestinal topography and assess inflammation. We examine the mucosal surface of >700 mice (encompassing >16 strains and various IBD-models), create a profiling catalogue of 3D-stereomicroscopic abnormalities and demonstrate that mice with comparable histological scores display unique sub-clusters of 3D-structure-patterns of IBD pathology, which we call 3D-stereoenterotypes, and which are otherwise indiscernible histologically. We show that two ileal IBD-stereoenterotypes ('cobblestones' versus 'villous mini-aggregation') cluster separately within two distinct mouse lines of spontaneous ileitis, suggesting that host genetics drive unique and divergent inflammatory 3D-structural patterns in the gut. In humans, stereomicroscopy reveals 'liquefaction' lesions and hierarchical fistulous complexes, enriched with clostridia/segmented filamentous bacteria, running under healthy mucosa in Crohn's disease. We suggest that stereomicroscopic (3D-SMAPgut) profiling can be easily implemented and enable the comprehensive study of inflammatory 3D structures, genetics and flora in IBD.
Assuntos
Inflamação/patologia , Enteropatias/patologia , Mucosa Intestinal/patologia , Microscopia/métodos , Animais , Feminino , Humanos , Enteropatias/induzido quimicamente , Enteropatias/genética , Enteropatias/microbiologia , Masculino , Camundongos , Camundongos EndogâmicosRESUMO
Increasing evidence suggests that a deficit in innate immunity may play a causative role in the pathogenesis of inflammatory bowel disease. The most compelling support for this hypothesis comes from the genetic association of Crohn disease (CD) with carriage of polymorphisms within the NOD2 gene, which represent the most frequent genetic defect in CD. Our findings suggest that SAMP1/YitFc mice, which develop CD-like ileitis in the absence of NOD2 genetic mutations, fail to respond to MDP administration by displaying decreased innate cytokine production and impaired bacterial clearance before the onset of disease. This provides evidence that dysregulated NOD2 signaling, genetic or functional in nature, predisposes to chronic intestinal inflammation, and supports a new paradigm that CD may occur from a deficit in innate immunity as opposed to an overly aggressive immune response. This new paradigm could lead to potential development of new preventative or therapeutic modalities for patients with CD.
Assuntos
Doença de Crohn/imunologia , Doença de Crohn/fisiopatologia , Proteína Adaptadora de Sinalização NOD2/deficiência , Transdução de Sinais , Animais , Modelos Animais de Doenças , Humanos , Síndromes de Imunodeficiência/fisiopatologia , CamundongosRESUMO
Inflammatory bowel diseases (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), are chronic, relapsing inflammatory condition of the gastrointestinal tract. CD and UC have distinct pathologic and clinical characteristics and despite the extensive amount of research conducted over the past decades, their pathogenesis remains still poorly understood. So far, the accepted dogma is that IBD results from dysregulated mucosal immune response to environmental factors in genetical susceptible hosts. Various components are implicated in the pathogenesis of IBD, including genetic susceptibility, environmental and microbial factors, intestinal epithelial cells and components of innate and adaptive immune system. Given the complexity of IBD, several different animal models of IBD have been developed during the last years. Animal models are very important tools to study the involvement of various factors in the pathogenesis of IBD and, importantly, to test new therapeutic options. This review examines some of the key components that have been found to be closely associated to IBD and describe the distinct features of some of the most important IBD models.