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Fallo Hepático , Regeneración Hepática , Inhibidores de Proteínas Quinasas , Humanos , Regeneración Hepática/efectos de los fármacos , Inhibidores de Proteínas Quinasas/farmacología , Inhibidores de Proteínas Quinasas/uso terapéutico , Fallo Hepático/prevención & control , Fallo Hepático/genética , AnimalesRESUMEN
Lipid composition is conserved within sub-cellular compartments to maintain cell function. Lipidomic analyses of liver, muscle, white and brown adipose tissue (BAT) mitochondria revealed substantial differences in their glycerophospholipid (GPL) and free cholesterol (FC) contents. The GPL to FC ratio was 50-fold higher in brown than white adipose tissue mitochondria. Their purity was verified by comparison of proteomes with ER and mitochondria-associated membranes. A lipid signature containing PC and FC, calculated from the lipidomic profiles, allowed differentiation of mitochondria from BAT of mice housed at different temperatures. Elevating FC in BAT mitochondria prevented uncoupling protein (UCP) 1 function, whereas increasing GPL boosted it. Similarly, STARD3 overexpression facilitating mitochondrial FC import inhibited UCP1 function in primary brown adipocytes, whereas a knockdown promoted it. We conclude that the mitochondrial GPL/FC ratio is key for BAT function and propose that targeting it might be a promising strategy to promote UCP1 activity.
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Tejido Adiposo Pardo , Colesterol , Lipidómica , Mitocondrias , Proteína Desacopladora 1 , Animales , Proteína Desacopladora 1/metabolismo , Proteína Desacopladora 1/genética , Ratones , Tejido Adiposo Pardo/metabolismo , Colesterol/metabolismo , Mitocondrias/metabolismo , Lipidómica/métodos , Especificidad de Órganos , Ratones Endogámicos C57BL , Tejido Adiposo Blanco/metabolismo , Glicerofosfolípidos/metabolismo , Masculino , Metabolismo de los LípidosRESUMEN
The gut microbiota influences human health and the development of chronic diseases. However, our understanding of potentially protective or harmful microbe-host interactions at the molecular level is still in its infancy. To gain further insights into the hidden gut metabolome and its impact, we identified a cryptic non-ribosomal peptide BGC in the genome of Bacillus cereus DSM 28590 from the mouse intestine ( www.dsmz.de/miBC ), which was predicted to encode a thiazol(in)e substructure. Cloning and heterologous expression of this BGC revealed that it produces bacillamide D. In-depth functional evaluation showed potent cytotoxicity and inhibition of cell migration using the human cell lines HCT116 and HEK293, which was validated using primary mouse organoids. This work establishes the bacillamides as selective cytotoxins from a bacterial gut isolate that affect mammalian cells. Our targeted structure-function-predictive approach is demonstrated to be a streamlined method to discover deleterious gut microbial metabolites with potential effects on human health.
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Bacillus cereus , Microbioma Gastrointestinal , Bacillus cereus/metabolismo , Bacillus cereus/genética , Animales , Ratones , Humanos , Células HEK293 , Citotoxinas/metabolismo , Citotoxinas/genética , Células HCT116 , Intestinos/microbiología , Movimiento Celular , Organoides/metabolismoRESUMEN
The microbiome is a predictor of clinical outcome in patients receiving allogeneic hematopoietic stem cell transplantation (allo-SCT). Microbiota-derived metabolites can modulate these outcomes. How bacteria, fungi and viruses contribute to the production of intestinal metabolites is still unclear. We combined amplicon sequencing, viral metagenomics and targeted metabolomics from stool samples of patients receiving allo-SCT (n = 78) and uncovered a microbiome signature of Lachnospiraceae and Oscillospiraceae and their associated bacteriophages, correlating with the production of immunomodulatory metabolites (IMMs). Moreover, we established the IMM risk index (IMM-RI), which was associated with improved survival and reduced relapse. A high abundance of short-chain fatty acid-biosynthesis pathways, specifically butyric acid via butyryl-coenzyme A (CoA):acetate CoA-transferase (BCoAT, which catalyzes EC 2.8.3.8) was detected in IMM-RI low-risk patients, and virome genome assembly identified two bacteriophages encoding BCoAT as an auxiliary metabolic gene. In conclusion, our study identifies a microbiome signature associated with protective IMMs and provides a rationale for considering metabolite-producing consortia and metabolite formulations as microbiome-based therapies.
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Bacteriófagos , Trasplante de Células Madre Hematopoyéticas , Humanos , Bacteriófagos/genética , Heces/microbiología , Trasplante de Células Madre Hematopoyéticas/efectos adversos , Bacterias/genética , Bacterias/metabolismo , Ácido Butírico/metabolismoRESUMEN
Dysregulated B cell responses have been described in inflammatory bowel disease (IBD) patients; however, the role of B cells in IBD pathology remained incompletely understood. We here provide evidence for the detrimental role of activated B cells during the onset of autoimmune intestinal inflammation. Using Wiskott-Aldrich Syndrome interacting protein deficient (Wipf1-/-) mice as a mouse model of chronic colitis, we identified clusters of differentiation (CD)86 expression on activated B cells as a crucial factor exacerbating pro-inflammatory cytokine production of intestinal CD4 T cells. Depleting B cells through anti-CD20 antibody treatment or blocking costimulatory signals mediated by CD86 through cytotoxic T lymphocyte antigen-4-immunoglobulin (CTLA-4-Ig) diminished intestinal inflammation in our mouse model of chronic IBD at the onset of disease. This was due to a reduction in aberrant humoral immune responses and reduced CD4 T cell pro-inflammatory cytokine production, especially interferon-g (IFN-g) and granulocyte-macrophage colony-stimulating factor (GM-CSF). Interestingly, in addition to B cells isolated from the inflamed colon of Wipf1-/- mice, we also found CD86 mRNA and protein expression upregulated on activated B cells isolated from inflamed tissue of human patients with IBD. B cell activation and CD86 expression were boosted by soluble CD40L in vitro, which we found in the serum of mice and human patients with IBD. In summary, our data provides detailed insight into the contribution of B cells to intestinal inflammation, with implications for the treatment of IBD.
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Colitis , Enfermedades Inflamatorias del Intestino , Humanos , Linfocitos T CD4-Positivos , Inflamación/metabolismo , Mucosa Intestinal , Intestinos/patologíaRESUMEN
INTRODUCTION: The identification of risk factors for precursor lesions of colorectal cancer (CRC) holds great promise in the context of prevention. With this study, we aimed to identify patient characteristics associated with colorectal polyps (CPs) and polyp features of potential malignant progression. Furthermore, a potential association with gut microbiota in this context was investigated. METHODS: In this single-center study, a total of 162 patients with CPs and 91 control patients were included. Multiple variables including information on lifestyle, diet, serum parameters, and gut microbiota, analyzed by 16S-rRNA gene amplicon sequencing and functional imputations (Picrust2), were related to different aspects of CPs. RESULTS: We observed that elevated serum alkaline phosphatase (AP) levels were significantly associated with the presence of high-grade dysplastic polyps. This association was further seen for patients with CRC. Thereby, AP correlated with other parameters of liver function. We did not observe significant changes in the gut microbiota between patients with CP and their respective controls. However, a trend toward a lower alpha-diversity was seen in patients with CRC. Interestingly, AP was identified as a possible clinical effect modifier of stool sample beta diversity. DISCUSSION: We show for the first time an increased AP in premalignant CP. Furthermore, AP showed a significant influence on the microbial composition of the intestine. Relatively elevated liver enzymes, especially AP, may contribute to the detection of precancerous dysplastic or neoplastic changes in colorectal lesions. The association between elevated AP, premalignant CP, and the microbiome merits further study.
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Pólipos del Colon , Neoplasias Colorrectales , Microbioma Gastrointestinal , Humanos , Neoplasias Colorrectales/genética , Pólipos del Colon/diagnóstico , Pólipos del Colon/patología , Bacterias , Heces , Microbioma Gastrointestinal/genética , HiperplasiaRESUMEN
The G-protein-coupled receptor LGR6 associates with ligands of the R-Spondin (RSPO) family to potentiate preexisting signals of the canonical WNT pathway. However, its importance in pancreatic ductal adenocarcinoma (PDAC) remains unclear. Here, we show that LGR6 is differentially expressed in various PDAC cell lines of mesenchymal and epithelial phenotype, respectively, siding with the latter subsets. LGR6 expression is altered based upon the cells' WNT activation status. Furthermore, extrinsic enhancement of WNT pathway signaling increased LGR6 expression suggestive of a reinforcing self-regulatory loop in highly WNT susceptible cells. Downregulation of LGR6 on the other hand, seemed to tamper those effects. Last, downregulation of LGR6 reduced cancer stemness as determined by functional in vitro assays. These findings shed new insights into regulatory mechanisms for the canonical WNT pathway in pancreatic cancer cells. It may also have potential value for treatment stratification of PDAC.
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Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Humanos , Neoplasias Pancreáticas/patología , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Vía de Señalización Wnt/genética , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/patología , Neoplasias PancreáticasRESUMEN
The actin-regulated transcription factor MRTF-A represents a central relay in mechanotransduction and controls a subset of SRF-dependent target genes. However, gain-of-function studies in vivo are lacking. Here we characterize a conditional MRTF-A transgenic mouse model. While MRTF-A gain-of-function impaired embryonic development, induced expression of constitutively active MRTF-A provoked rapid hepatocyte ballooning and liver failure in adult mice. Specific expression in the intestinal epithelium caused an erosive architectural distortion, villus blunting, cryptal hyperplasia and colonic inflammation, resulting in transient weight loss. Organoids from transgenic mice repeatedly induced in vitro showed impaired self-renewal and defective cryptal compartments. Mechanistically, MRTF-A gain-of-function decreased proliferation and increased apoptosis, but did not induce fibrosis. MRTF-A targets including Acta2 and Pai-1 were induced, whereas markers of stem cells and differentiated cells were reduced. Our results suggest that activated MRTF-A in the intestinal epithelium shifts the balance between proliferation, differentiation and apoptosis.
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Mutación con Ganancia de Función , Transactivadores , Ratones , Animales , Transactivadores/genética , Transactivadores/metabolismo , Mecanotransducción Celular , Transducción de Señal/genética , Ratones Transgénicos , Mucosa Intestinal/metabolismo , Factor de Respuesta Sérica/metabolismoRESUMEN
Acute graft-versus-host disease (aGvHD) is a significant complication after allogeneic hematopoietic stem cell transplantation (aHSCT), but major factors determining disease severity are not well defined yet. By combining multiplexed tissue imaging and single-cell RNA sequencing on gastrointestinal biopsies from aHSCT-treated individuals with fecal microbiome analysis, we link high microbiome diversity and the abundance of short-chain fatty acid-producing bacteria to the sustenance of suppressive regulatory T cells (Tregs). Furthermore, aGvHD severity strongly associates with the clonal expansion of mainly CD8 T cells, which we find distributed over anatomically distant regions of the gut, persistent over time, and inversely correlated with the presence of suppressive Tregs. Overall, our study highlights the pathophysiological importance of expanded CD8 T cell clones in the progression of aGvHD toward more severe clinical manifestations and strongly supports the further development of microbiome interventions as GvHD treatment via repopulation of the gut Treg niche to suppress inflammation.
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Enfermedad Injerto contra Huésped , Trasplante de Células Madre Hematopoyéticas , Microbiota , Humanos , Enfermedad Injerto contra Huésped/patología , Microbiota/genética , Trasplante de Células Madre Hematopoyéticas/efectos adversos , Tracto Gastrointestinal/patología , Linfocitos T CD8-positivos/patologíaRESUMEN
BACKGROUND: Cancer cachexia (CCx) is a complex and multi-organ wasting syndrome characterized by substantial weight loss and poor prognosis. An improved understanding of the mechanisms involved in the onset and progression of cancer cachexia is essential. How microRNAs contribute to the clinical manifestation and progression of CCx remains elusive. The aim of this study was to identify specific miRNAs related to organ-specific CCx and explore their functional role in humans. METHODS: miRNA patterns in serum and in cachexia target organs (liver, muscle and adipose tissue) from weight stable (N ≤ 12) and cachectic patients (N ≤ 23) with gastrointestinal cancer were analysed. As a first step, a miRNA array (158 miRNAs) was performed in pooled serum samples. Identified miRNAs were validated in serum and corresponding tissue samples. Using in silico prediction, related genes were identified and evaluated. The findings were confirmed in vitro by siRNA knock-down experiments in human visceral preadipocytes and C2C12 myoblast cells and consecutive gene expression analyses. RESULTS: Validating the results of the array, a 2-fold down-regulation of miR-122-5p (P = 0.0396) and a 4.5-fold down-regulation of miR-194-5p (P < 0.0001) in serum of CCx patients in comparison with healthy controls were detected. Only miR-122-5p correlated with weight loss and CCx status (P = 0.0367). Analysing corresponding tissues six muscle and eight visceral adipose tissue (VAT) cachexia-associated miRNAs were identified. miR-27b-3p, miR-375 and miR-424-5p were the most consistently affected miRNAs in tissues of CCx patients correlating negatively with the severity of body weight loss (P = 0.0386, P = 0.0112 and P = 0.0075, respectively). We identified numerous putative target genes of the miRNAs in association with muscle atrophy and lipolysis pathways. Knock-down experiments in C2C12 myoblast cells revealed an association of miR-27b-3p and the in silico predicted atrophy-related target genes IL-15 and TRIM63. Both were up-regulated in miR-27b-3p knock-down cells (P < 0.05). Concordantly, in muscle tissue of CCx individuals, significant higher expression levels of IL-15 (P = 0.0237) and TRIM63 (P = 0.0442) were detected. miR-424-5p was identified to regulate the expression of lipase genes. Knock-down experiments in human visceral preadipocytes revealed an inverse association of miR-424-5p with its predicted target genes LIPE, PNPLA2, MGLL and LPL (P < 0.01). CONCLUSIONS: The identified miRNAs, in particular miR-122-5p, miR-27b-3p, miR-375 and miR-424-5p, represent features of human CCx and may contribute to tissue wasting and skeletal muscle atrophy through the regulation of catabolic signals. Further studies are needed to explore the potential of the identified miRNAs as a screening tool for early detection of cancer cachexia.
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MicroARNs , Neoplasias , Humanos , MicroARNs/genética , MicroARNs/metabolismo , Interleucina-15 , Caquexia/genética , Neoplasias/complicaciones , Neoplasias/genética , Pérdida de PesoRESUMEN
OBJECTIVE: Helicobacter pylori infection is the most prevalent bacterial infection worldwide. Besides being the most important risk factor for gastric cancer development, epidemiological data show that infected individuals harbour a nearly twofold increased risk to develop colorectal cancer (CRC). However, a direct causal and functional connection between H. pylori infection and colon cancer is lacking. DESIGN: We infected two Apc-mutant mouse models and C57BL/6 mice with H. pylori and conducted a comprehensive analysis of H. pylori-induced changes in intestinal immune responses and epithelial signatures via flow cytometry, chip cytometry, immunohistochemistry and single cell RNA sequencing. Microbial signatures were characterised and evaluated in germ-free mice and via stool transfer experiments. RESULTS: H. pylori infection accelerated tumour development in Apc-mutant mice. We identified a unique H. pylori-driven immune alteration signature characterised by a reduction in regulatory T cells and pro-inflammatory T cells. Furthermore, in the intestinal and colonic epithelium, H. pylori induced pro-carcinogenic STAT3 signalling and a loss of goblet cells, changes that have been shown to contribute-in combination with pro-inflammatory and mucus degrading microbial signatures-to tumour development. Similar immune and epithelial alterations were found in human colon biopsies from H. pylori-infected patients. Housing of Apc-mutant mice under germ-free conditions ameliorated, and early antibiotic eradication of H. pylori infection normalised the tumour incidence to the level of uninfected controls. CONCLUSIONS: Our studies provide evidence that H. pylori infection is a strong causal promoter of colorectal carcinogenesis. Therefore, implementation of H. pylori status into preventive measures of CRC should be considered.
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Neoplasias del Colon , Infecciones por Helicobacter , Helicobacter pylori , Microbiota , Neoplasias Gástricas , Humanos , Ratones , Animales , Helicobacter pylori/genética , Infecciones por Helicobacter/complicaciones , Infecciones por Helicobacter/microbiología , Ratones Endogámicos C57BL , Carcinogénesis/patología , Neoplasias Gástricas/patología , Neoplasias del Colon/patología , Moco , Mucosa Gástrica/patologíaRESUMEN
OBJECTIVES: Cancer is considered an emerging diabetes complication, with higher incidence and worse prognosis in patients with diabetes. Cancer is frequently associated with cachexia, a systemic metabolic disease causing wasting. It is currently unclear how diabetes affects the development and progression of cachexia. METHODS: We investigated the interplay between diabetes and cancer cachexia retrospectively in a cohort of 345 patients with colorectal and pancreatic cancer. We recorded body weight, fat mass, muscle mass, clinical serum values, and survival of these patients. Patients were grouped either into diabetic/non-diabetic groups based on previous diagnosis, or into obese/non-obese groups based on body mass index (BMI ≥30 kg/m2 was considered obese). RESULTS: The pre-existence of type 2 diabetes, but not obesity, in patients with cancer led to increased cachexia incidence (80%, compared to 61% without diabetes, p ≤ 0.05), higher weight loss (8.9% vs. 6.0%, p ≤ 0.001), and reduced survival probability (median survival days: 689 vs. 538, Chi square = 4.96, p ≤ 0.05) irrespective of the initial body weight or tumor progression. Patients with diabetes and cancer showed higher serum levels of C-reactive protein (0.919 µg/mL vs. 0.551 µg/mL, p ≤ 0.01) and interleukin 6 (5.98 pg/mL vs. 3.75 pg/mL, p ≤ 0.05) as well as lower serum albumin levels (3.98 g/dL vs. 4.18 g/dL, p ≤ 0.05) than patients with cancer without diabetes. In a sub-analysis of patients with pancreatic cancer, pre-existing diabetes worsened weight loss (9.95% vs. 6.93%, p ≤ 0.01), and increased the duration of hospitalization (24.41 days vs. 15.85 days, p ≤ 0.001). Further, diabetes aggravated clinical manifestations of cachexia, as changes in the aforementioned biomarkers were more pronounced in patients with diabetes and cachexia co-existence, compared to cachectic patients without diabetes (C-reactive protein: 2.300 µg/mL vs. 0.571 µg/mL, p ≤ 0.0001; hemoglobin: 11.24 g/dL vs. 12.52 g/dL, p ≤ 0.05). CONCLUSIONS: We show for the first time that pre-existing diabetes aggravates cachexia development in patients with colorectal and pancreatic cancer. This is important when considering cachexia biomarkers and weight management in patients with co-existing diabetes and cancer.
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Neoplasias Colorrectales , Diabetes Mellitus Tipo 2 , Neoplasias Pancreáticas , Humanos , Caquexia/metabolismo , Estudios Retrospectivos , Proteína C-Reactiva , Diabetes Mellitus Tipo 2/complicaciones , Neoplasias Pancreáticas/complicaciones , Neoplasias Pancreáticas/metabolismo , Peso Corporal , Obesidad/complicaciones , Biomarcadores , Neoplasias Colorrectales/complicaciones , Neoplasias PancreáticasRESUMEN
BACKGROUND & AIMS: Hepatocyte growth and proliferation depends on membrane phospholipid biosynthesis. Short-chain fatty acids (SCFAs) generated by bacterial fermentation, delivered through the gut-liver axis, significantly contribute to lipid biosynthesis. We therefore hypothesized that dysbiotic insults like antibiotic treatment not only affect gut microbiota, but also impair hepatic lipid synthesis and liver regeneration. METHODS: Stable isotope labeling and 70% partial hepatectomy (PHx) was carried out in C57Bl/6J wild-type mice, in mice treated with broad-spectrum antibiotics, in germ-free mice and mice colonized with minimal microbiota. The microbiome was analyzed by 16S rRNA gene sequencing and microbial culture. Gut content, liver, blood and primary hepatocyte organoids were tested by mass spectrometry-based lipidomics, quantitative reverse-transcription PCR (qRT-PCR), immunoblot and immunohistochemistry for expression of proliferative and lipogenic markers. Matched biopsies from hyperplastic and hypoplastic liver tissue of patients subjected to surgical intervention to induce hyperplasia were analyzed by qRT-PCR for lipogenic enzymes. RESULTS: Three days of antibiotic treatment induced persistent dysbiosis with significantly decreased beta-diversity and richness, but a massive increase of Proteobacteria, accompanied by decreased colonic SCFAs. After PHx, antibiotic-treated mice showed delayed liver regeneration, increased mortality, impaired hepatocyte proliferation and decreased hepatic phospholipid synthesis. Expression of the lipogenic enzyme SCD1 was upregulated after PHx but delayed by antibiotic treatment. Germ-free mice essentially recapitulated the phenotype of antibiotic treatment. Phospholipid biosynthesis, hepatocyte proliferation, liver regeneration and survival were rescued in gnotobiotic mice colonized with a minimal SCFA-producing microbial community. SCFAs induced the growth of murine hepatocyte organoids and hepatic SCD1 expression in mice. Further, SCD1 was required for proliferation of human hepatoma cells and was associated with liver regeneration in human patients. CONCLUSION: Gut microbiota are pivotal for hepatic membrane phospholipid biosynthesis and liver regeneration. IMPACT AND IMPLICATIONS: Gut microbiota affect hepatic lipid metabolism through the gut-liver axis, but the underlying mechanisms are poorly understood. Perturbations of the gut microbiome, e.g. by antibiotics, impair the production of bacterial metabolites, which normally serve as building blocks for membrane lipids in liver cells. As a consequence, liver regeneration and survival after liver surgery is severely impaired. Even though this study is preclinical, its results might allow physicians in the future to improve patient outcomes after liver surgery, by modulation of gut microbiota or their metabolites.
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Membrana Celular , Microbioma Gastrointestinal , Hepatocitos , Regeneración Hepática , Fosfolípidos , Animales , Humanos , Ratones , Antibacterianos/farmacología , Microbioma Gastrointestinal/genética , Microbioma Gastrointestinal/fisiología , Hiperplasia/metabolismo , Hiperplasia/patología , Hígado/patología , Regeneración Hepática/fisiología , Ratones Endogámicos C57BL , Fosfolípidos/biosíntesis , Fosfolípidos/metabolismo , ARN Ribosómico 16S , Hepatocitos/metabolismo , Membrana Celular/metabolismoRESUMEN
OBJECTIVES: COVID-19 disease can be exacerbated by Aspergillus superinfection (CAPA). However, the causes of CAPA are not yet fully understood. Recently, alterations in the gut microbiome have been associated with a more complicated and severe disease course in COVID-19 patients, most likely due to immunological mechanisms. The aim of this study was to investigate a potential association between severe CAPA and alterations in the gut and bronchial microbial composition. METHODS: We performed 16S rRNA gene amplicon sequencing of stool and bronchial samples from a total of 16 COVID-19 patients with CAPA and 26 patients without CAPA. All patients were admitted to the intensive care unit. Results were carefully tested for potentially confounding influences on the microbiome during hospitalization. RESULTS: We found that late in COVID-19 disease, CAPA patients exhibited a trend towards reduced gut microbial diversity. Furthermore, late-stage patients with CAPA superinfection exhibited an increased abundance of Staphylococcus epidermidis in the gut which was not found in late non-CAPA cases or early in the disease. The analysis of bronchial samples did not yield significant results. CONCLUSIONS: This is the first study showing that alterations in the gut microbiome accompany severe CAPA and possibly influence the host's immunological response. In particular, an increase in Staphylococcus epidermidis in the intestine could be of importance.
RESUMEN
Intestinal epithelial cells absorb nutrients through the brush border, composed of dense arrays of highly ordered microvilli at their apical membranes. A protocadherin-based intermicrovillar adhesion complex localized at microvilli tips mediates microvilli packing and organization. Here, we identified a second adhesion complex localized at the proximal base region of microvilli. This complex contained the immunoglobulin superfamily member TMIGD1, which directly interacted with the microvillar scaffolding proteins EBP50 and E3KARP. Complex formation with EBP50 required the activation of EBP50 by the actin-binding protein ezrin and was enhanced by the dephosphorylation of Ser162 in the PDZ2 domain of EBP50 by the phosphatase PP1α. Binding of the EBP50-ezrin complex to TMIGD1 enhanced the dynamic turnover of EBP50 at microvilli. Enterocyte-specific inactivation of Tmigd1 in mice resulted in microvillar blebbing, loss of intermicrovillar adhesion, and perturbed brush border formation. Thus, we identified a second adhesion complex in microvilli and propose a mechanism that promotes microvillar formation and dynamics.
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Células Epiteliales , Intestinos , Glicoproteínas de Membrana/metabolismo , Animales , Membrana Celular/metabolismo , Células Epiteliales/metabolismo , Ratones , Proteínas de Microfilamentos/genética , Proteínas de Microfilamentos/metabolismo , Microvellosidades/metabolismoRESUMEN
Micronuclei are DNA-containing structures separate from the nucleus found in cancer cells. Micronuclei are recognized by the immune sensor axis cGAS/STING, driving cancer metastasis. The mitochondrial apoptosis apparatus can be experimentally triggered to a non-apoptotic level, and this can drive the appearance of micronuclei through the Caspase-activated DNAse (CAD). We tested whether spontaneously appearing micronuclei in cancer cells are linked to sub-lethal apoptotic signals. Inhibition of mitochondrial apoptosis or of CAD reduced the number of micronuclei in tumor cell lines as well as the number of chromosomal misalignments in tumor cells and intestinal organoids. Blockade of mitochondrial apoptosis or deletion of CAD reduced, while experimental activation CAD, STING-dependently, enhanced aggressive growth of tumor cells in vitro. Deletion of CAD from human cancer cells reduced metastasis in xenograft models. CAD-deficient cells displayed a substantially altered gene-expression profile, and a CAD-associated gene expression 'signature' strongly predicted survival in cancer patients. Thus, low-level activity in the mitochondrial apoptosis apparatus operates through CAD-dependent gene-induction and STING-activation and has substantial impact on metastasis in cancer.
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Desoxirribonucleasas , Neoplasias , Animales , Apoptosis/genética , Proteínas Reguladoras de la Apoptosis/metabolismo , Núcleo Celular/metabolismo , ADN/metabolismo , Desoxirribonucleasas/metabolismo , Humanos , Neoplasias/metabolismoRESUMEN
The cytoplasmic phosphatase DUSP6 and its nuclear counterpart DUSP5 are negative regulators of RAS/ERK signalling. Here we use deletion of either Dusp5 or Dusp6 to explore the roles of these phosphatases in a murine model of KRASG12D-driven pancreatic cancer. By 56-days, loss of either DUSP5 or DUSP6 causes a significant increase in KRASG12D-driven pancreatic hyperplasia. This is accompanied by increased pancreatic acinar to ductal metaplasia (ADM) and the development of pre-neoplastic pancreatic intraepithelial neoplasia (PanINs). In contrast, by 100-days, pancreatic hyperplasia is reversed with significant atrophy of pancreatic tissue and weight loss observed in animals lacking either DUSP5 or DUSP6. On further ageing, Dusp6-/- mice display accelerated development of metastatic pancreatic ductal adenocarcinoma (PDAC), while in Dusp5-/- animals, although PDAC development is increased this process is attenuated by atrophy of pancreatic acinar tissue and severe weight loss in some animals before cancer could progress. Our data suggest that despite a common target in the ERK MAP kinase, DUSP5 and DUSP6 play partially non-redundant roles in suppressing oncogenic KRASG12D signalling, thus retarding both tumour initiation and progression. Our data suggest that loss of either DUSP5 or DUSP6, as observed in certain human tumours, including the pancreas, could promote carcinogenesis.
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Carcinoma Ductal Pancreático , Fosfatasa 6 de Especificidad Dual , Fosfatasas de Especificidad Dual , Neoplasias Pancreáticas , Animales , Atrofia/patología , Carcinogénesis/genética , Carcinogénesis/patología , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/patología , Fosfatasa 6 de Especificidad Dual/genética , Fosfatasas de Especificidad Dual/genética , Hiperplasia , Ratones , Páncreas/patología , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patología , Proteínas Proto-Oncogénicas p21(ras)/genética , Pérdida de Peso , Neoplasias PancreáticasRESUMEN
There is a growing debate about the involvement of the gut microbiome in COVID-19, although it is not conclusively understood whether the microbiome has an impact on COVID-19, or vice versa, especially as analysis of amplicon data in hospitalized patients requires sophisticated cohort recruitment and integration of clinical parameters. Here, we analyzed fecal and saliva samples from SARS-CoV-2 infected and post COVID-19 patients and controls considering multiple influencing factors during hospitalization. 16S rRNA gene sequencing was performed on fecal and saliva samples from 108 COVID-19 and 22 post COVID-19 patients, 20 pneumonia controls and 26 asymptomatic controls. Patients were recruited over the first and second corona wave in Germany and detailed clinical parameters were considered. Serial samples per individual allowed intra-individual analysis. We found the gut and oral microbiota to be altered depending on number and type of COVID-19-associated complications and disease severity. The occurrence of individual complications was correlated with low-risk (e.g., Faecalibacterium prausznitzii) and high-risk bacteria (e.g., Parabacteroides ssp.). We demonstrated that a stable gut bacterial composition was associated with a favorable disease progression. Based on gut microbial profiles, we identified a model to estimate mortality in COVID-19. Gut microbiota are associated with the occurrence of complications in COVID-19 and may thereby influencing disease severity. A stable gut microbial composition may contribute to a favorable disease progression and using bacterial signatures to estimate mortality could contribute to diagnostic approaches. Importantly, we highlight challenges in the analysis of microbial data in the context of hospitalization.
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COVID-19/microbiología , Disbiosis/microbiología , Microbioma Gastrointestinal , Anciano , Bacterias/clasificación , Bacterias/genética , Bacterias/aislamiento & purificación , COVID-19/complicaciones , COVID-19/mortalidad , Progresión de la Enfermedad , Disbiosis/etiología , Heces/microbiología , Femenino , Humanos , Masculino , Microbiota , Persona de Mediana Edad , SARS-CoV-2 , Saliva/microbiología , Índice de Severidad de la EnfermedadRESUMEN
The B subunit of bacterial Shiga toxin (STxB) is nontoxic and has low immunogenicity. Its receptor, the glycosphingolipid Gb3/CD77, is overexpressed on the cell surface of human colorectal cancer. We tested whether genetic porcine models, closely resembling human anatomy and pathophysiology, can be used to exploit the tumor-targeting potential of STxB. In accordance with findings on human colorectal cancer, the pig model APC1311 bound STxB in colorectal tumors, but not in normal colon or jejunum, except for putative enteroendocrine cells. In primary tumor cells from endoscopic biopsies, STxB was rapidly taken up along the retrograde intracellular route to the Golgi, whereas normal colon organoids did not bind or internalize STxB. Next, we tested a porcine model (TP53LSL-R167H) for osteosarcoma, a tumor entity with a dismal prognosis and insufficient treatment options, hitherto not known to express Gb3. Pig osteosarcoma strongly bound StxB and expressed the Gb3 synthase 1,4-galactosyltransferase (A4GALT). Primary osteosarcoma cells, but not normal osteoblasts, rapidly internalized fluorescently labeled STxB along the retrograde route to the Golgi. Importantly, six of eight human osteosarcoma cell lines expressed A4GALT mRNA and showed prominent intracellular uptake of STxB. The physiologic role of A4GALT was tested by CRISPR/Cas9 mutagenesis in porcine LLC-PK1 kidney epithelial cells and RNAi in MG-63 human osteosarcoma cells. A4GALT deficiency or knockdown abolished STxB uptake and led to significantly reduced cell migration and proliferation, hinting toward a putative tumor-promoting role of Gb3. Thus, pig models are suitable tools for STxB-based tumor targeting and may allow "reverse-translational" predictions on human tumor biology.