RESUMEN
Juvenile dermatomyositis (JDM) is a rare immune-mediated disease of childhood with putative links to microbial exposures. In this multi-center, prospective, observational cohort study, we evaluated whether JDM is associated with discrete oral and gut microbiome signatures. We generated 16S rRNA sequencing data from fecal, saliva, supragingival, and subgingival plaque samples from JDM probands (n = 28). To control for genetic and environmental determinants of microbiome community structure, we also profiled microbiomes of unaffected family members (n = 27 siblings, n = 26 mothers, and n = 17 fathers). Sample type (oral-vs-fecal) and nuclear family unit were the predominant variables explaining variance in microbiome diversity, more so than having a diagnosis of JDM. The oral and gut microbiomes of JDM probands were more similar to their own unaffected siblings than they were to the microbiomes of other JDM probands. In a sibling-paired within-family analysis, several potentially immunomodulatory bacterial taxa were differentially abundant in the microbiomes of JDM probands compared to their unaffected siblings, including Faecalibacterium (gut) and Streptococcus (oral cavity). While microbiome features of JDM are often shared by unaffected family members, the loss or gain of specific fecal and oral bacteria may play a role in disease pathogenesis or be secondary to immune dysfunction in susceptible individuals.
Asunto(s)
Dermatomiositis , Heces , Microbioma Gastrointestinal , Boca , ARN Ribosómico 16S , Humanos , Heces/microbiología , Dermatomiositis/microbiología , Dermatomiositis/genética , Femenino , Masculino , Niño , Boca/microbiología , ARN Ribosómico 16S/genética , Microbioma Gastrointestinal/genética , Estudios Prospectivos , Disbiosis/microbiología , Microbiota/genética , Preescolar , Adolescente , Saliva/microbiología , AdultoRESUMEN
Acute graft-versus-host disease (aGVHD) remains a major limitation of allogeneic stem cell transplantation (SCT), and severe intestinal manifestation is the major cause of early mortality. Intestinal microbiota control MHC class II (MHC-II) expression by ileal intestinal epithelial cells (IECs) that promote GVHD. Here, we demonstrated that genetically identical mice of differing vendor origins had markedly different intestinal microbiota and ileal MHC-II expression, resulting in discordant GVHD severity. We utilized cohousing and antibiotic treatment to characterize the bacterial taxa positively and negatively associated with MHC-II expression. A large proportion of bacterial MHC-II inducers were vancomycin sensitive, and peri-transplant oral vancomycin administration attenuated CD4+ T cell-mediated GVHD. We identified a similar relationship between pre-transplant microbes, HLA class II expression, and both GVHD and mortality in a large clinical SCT cohort. These data highlight therapeutically tractable mechanisms by which pre-transplant microbial taxa contribute to GVHD independently of genetic disparity.
Asunto(s)
Microbioma Gastrointestinal , Enfermedad Injerto contra Huésped , Trasplante de Células Madre Hematopoyéticas , Ratones , Animales , Vancomicina , Enfermedad Injerto contra Huésped/etiología , Trasplante de Células Madre Hematopoyéticas/efectos adversos , Trasplante de Células Madre Hematopoyéticas/métodos , Trasplante Homólogo/efectos adversosRESUMEN
Ret is implicated in colorectal cancer (CRC) as both a proto-oncogene and a tumor suppressor. We asked whether RET signaling regulates tumorigenesis in an Apc-deficient preclinical model of CRC. We observed a sex-biased phenotype: Apc Min/+ Ret+/- females had significantly greater tumor burden than Apc Min/+Ret+/- males, a phenomenon not seen in Apc Min/+ mice, which had equal distributions by sex. Dysfunctional RET signaling was associated with gene expression changes in diverse tumor signaling pathways in tumors and normal-appearing colon. Sex-biased gene expression differences mirroring tumor phenotypes were seen in 26 genes, including the Apc tumor suppressor gene. Ret and Tlr4 expression were significantly correlated in tumor samples from female but not male Apc Min/+ Ret+/- mice. Antibiotics resulted in reduction of tumor burden, inverting the sex-biased phenotype such that microbiota-depleted Apc Min/+ Ret+/- males had significantly more tumors than female littermates. Reconstitution of the microbiome rescued the sex-biased phenotype. Our findings suggest that RET represents a sexually dimorphic microbiome-mediated "switch" for regulation of tumorigenesis.
RESUMEN
Gastrointestinal motility is regulated by a variety of environmental factors including gut microbes and metabolites. The ability to interrogate mouse models of gut motility has enabled elucidation of these relationships. Here we describe integration of the red carmine dye and fluorescence isothiocyanate-dextran marker-based assays for characterizing gut transit with spatial resolution, along with an optional intracolonic infusion protocol for studying the effects of metabolites on colonic transit. These protocols can be adapted for use in gnotobiotic and conventional mouse models. For complete details on the use and execution of this protocol, please refer to Li et al. (2021).
Asunto(s)
Modelos Animales de Enfermedad , Tránsito Gastrointestinal/fisiología , Animales , Biomarcadores/metabolismo , Heces/química , Femenino , Tracto Gastrointestinal/química , Tracto Gastrointestinal/metabolismo , Vida Libre de Gérmenes , Masculino , RatonesRESUMEN
Gut motility is regulated by the microbiome via mechanisms that include bile acid metabolism. To localize the effects of microbiome-generated bile acids, we colonized gnotobiotic mice with different synthetic gut bacterial communities that were metabolically phenotyped using a functional in vitro screen. Using two different marker-based assays of gut transit, we inferred that bile acids exert effects on colonic transit. We validated this using an intra-colonic bile acid infusion assay and determined that these effects were dependent upon signaling via the bile acid receptor, TGR5. The intra-colonic bile acid infusion experiments further revealed sex-biased bile acid-specific effects on colonic transit, with lithocholic acid having the largest pro-motility effect. Transcriptional responses of the enteric nervous system (ENS) were stereotypic, regional, and observed in response to different microbiota, their associated bile acid profiles, and even to a single diet ingredient, evidencing exquisite sensitivity of the ENS to environmental perturbations.
RESUMEN
COVID-19 (coronavirus disease 2019) patients exhibiting gastrointestinal symptoms are reported to have worse prognosis. Ace2 (angiotensin-converting enzyme 2), the gene encoding the host protein to which SARS-CoV-2 spike proteins bind, is expressed in the gut and therefore may be a target for preventing or reducing severity of COVID-19. Here we test the hypothesis that Ace2 expression in the gastrointestinal and respiratory tracts is modulated by the microbiome. We used quantitative PCR to profile Ace2 expression in germ-free mice, conventional raised specific pathogen-free mice, and gnotobiotic mice colonized with different microbiota. Intestinal Ace2 expression levels were significantly higher in germ-free mice compared to conventional mice. A similar trend was observed in the respiratory tract. Intriguingly, microbiota depletion via antibiotics partially recapitulated the germ-free phenotype, suggesting potential for microbiome-mediated regulation of Ace2 expression. Variability in intestinal Ace2 expression was observed in gnotobiotic mice colonized with different microbiota, partially attributable to differences in microbiome-encoded proteases and peptidases. Together, these data suggest that the microbiome may be one modifiable factor determining COVID-19 infection risk and disease severity.
Asunto(s)
Enzima Convertidora de Angiotensina 2/metabolismo , Colon/enzimología , Microbioma Gastrointestinal , Intestino Delgado/enzimología , Pulmón/enzimología , Proteína de la Poliposis Adenomatosa del Colon/deficiencia , Proteína de la Poliposis Adenomatosa del Colon/genética , Enzima Convertidora de Angiotensina 2/genética , Animales , Femenino , Expresión Génica , Interleucina-10/deficiencia , Interleucina-10/genética , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones NoqueadosRESUMEN
Growing evidence indicates a role for the gut microbiota in modulating anti-tumor treatment efficacy in human cancer. Here we study mucosa-associated invariant T (MAIT) cells to look for evidence of bacterial antigen recognition in human colon, lung, and kidney carcinomas. Using mass cytometry and single-cell mRNA sequencing, we identify a tumor-infiltrating MAIT cell subset expressing CD4 and Foxp3 and observe high expression of CD39 on MAIT cells from colorectal cancer (CRC) only, which we show in vitro to be expressed specifically after TCR stimulation. We further reveal that these cells are phenotypically and functionally exhausted. Sequencing data show high bacterial infiltration in CRC tumors and highlight an enriched species, Fusobacteria nucleatum, with capability to activate MAIT cells in a TCR-dependent way. Our results provide evidence of a MAIT cell response to microbial antigens in CRC and could pave the way for manipulating MAIT cells or the microbiome for cancer therapy.
Asunto(s)
Antígenos Bacterianos/inmunología , Neoplasias Colorrectales/inmunología , Microbioma Gastrointestinal/inmunología , Células T Invariantes Asociadas a Mucosa/inmunología , Antígenos CD/inmunología , Apirasa/inmunología , Antígenos CD4/inmunología , Línea Celular Tumoral , Factores de Transcripción Forkhead/inmunología , Humanos , Activación de Linfocitos/inmunología , Receptores de Antígenos de Linfocitos T/inmunologíaRESUMEN
Circulating myostatin-attenuating agents are being developed to treat muscle-wasting disease despite their potential to produce serious off-target effects, as myostatin/activin receptors are widely distributed among many nonmuscle tissues. Our studies suggest that the myokine not only inhibits striated muscle growth but also regulates pituitary development and growth hormone (GH) action in the liver. Using a novel myostatin-null label-retaining model (Jekyll mice), we determined that the heterogeneous pool of pituitary stem, transit-amplifying, and progenitor cells in Jekyll mice depletes more rapidly after birth than the pool in wild-type mice. This correlated with increased levels of GH, prolactin, and the cells that secrete these hormones, somatotropes and lactotropes, respectively, in Jekyll pituitaries. Recombinant myostatin also stimulated GH release and gene expression in pituitary cell cultures although inhibiting prolactin release. In primary hepatocytes, recombinant myostatin blocked GH-stimulated expression of two key mediators of growth, insulin-like growth factor (IGF)1 and the acid labile subunit and increased expression of an inhibitor, IGF-binding protein-1. The significance of these findings was demonstrated by smaller muscle fiber size in a model lacking myostatin and liver IGF1 expression (LID-o-Mighty mice) compared with that in myostatin-null (Mighty) mice. These data together suggest that myostatin may regulate pituitary development and function and that its inhibitory actions in muscle may be partly mediated by attenuating GH action in the liver. They also suggest that circulating pharmacological inhibitors of myostatin could produce unintended consequences in these and possibly other tissues.
Asunto(s)
Hormona del Crecimiento/metabolismo , Hepatocitos/metabolismo , Factor I del Crecimiento Similar a la Insulina/metabolismo , Lactotrofos/metabolismo , Miostatina/genética , Hipófisis/crecimiento & desarrollo , Prolactina/metabolismo , Somatotrofos/metabolismo , Animales , Caquexia , Proteínas Portadoras/efectos de los fármacos , Proteínas Portadoras/metabolismo , Desarrollo de Medicamentos , Glicoproteínas/efectos de los fármacos , Glicoproteínas/metabolismo , Hormona del Crecimiento/efectos de los fármacos , Hepatocitos/efectos de los fármacos , Humanos , Proteína 1 de Unión a Factor de Crecimiento Similar a la Insulina/efectos de los fármacos , Proteína 1 de Unión a Factor de Crecimiento Similar a la Insulina/metabolismo , Factor I del Crecimiento Similar a la Insulina/efectos de los fármacos , Lactotrofos/efectos de los fármacos , Hígado/efectos de los fármacos , Hígado/metabolismo , Ratones , Ratones Noqueados , Modelos Animales , Miostatina/farmacología , Hipófisis/efectos de los fármacos , Hipófisis/metabolismo , Cultivo Primario de Células , Prolactina/efectos de los fármacos , Proteínas Recombinantes , Somatotrofos/efectos de los fármacos , Células MadreRESUMEN
A potentially novel approach for treating obesity includes attenuating myostatin as this increases muscle mass and decreases fat mass. Notwithstanding, conflicting studies report that myostatin stimulates or inhibits adipogenesis and it is unknown whether reduced adiposity with myostatin attenuation results from changes in fat deposition or adipogenesis. We therefore quantified changes in the stem, transit amplifying and progenitor cell pool in white adipose tissue (WAT) and brown adipose tissue (BAT) using label-retaining wild-type and mstn(-/-) (Jekyll) mice. Muscle mass was larger in Jekyll mice, WAT and BAT mass was smaller and label induction was equal in all tissues from both wild-type and Jekyll mice. The number of label-retaining cells, however, dissipated quicker in WAT and BAT of Jekyll mice and was only 25% and 17%, respectively, of wild-type cell counts 1 month after induction. Adipose cell density was significantly higher in Jekyll mice and increased over time concomitant with label-retaining cell disappearance, which is consistent with enhanced expansion and differentiation of the stem, transit amplifying and progenitor pool. Stromal vascular cells from Jekyll WAT and BAT differentiated into mature adipocytes at a faster rate than wild-type cells and although Jekyll WAT cells also proliferated quicker in vitro, those from BAT did not. Differentiation marker expression in vitro, however, suggests that mstn(-/-) BAT preadipocytes are far more sensitive to the suppressive effects of myostatin. These results suggest that myostatin attenuation stimulates adipogenesis in vivo and that the reduced adiposity in mstn(-/-) animals results from nutrient partitioning away from fat and in support of muscle.
Asunto(s)
Adipogénesis , Tejido Adiposo Pardo/citología , Tejido Adiposo Blanco/citología , Miostatina/antagonistas & inhibidores , Células Madre/citología , Regulación hacia Arriba , Tejido Adiposo Pardo/metabolismo , Tejido Adiposo Blanco/metabolismo , Adiposidad , Animales , Animales Recién Nacidos , Biomarcadores/metabolismo , Proliferación Celular , Células Cultivadas , Regulación hacia Abajo , Metabolismo Energético , Femenino , Humanos , Cinética , Ratones , Ratones Noqueados , Desarrollo de Músculos , Miostatina/genética , Miostatina/metabolismo , Células Madre/metabolismoRESUMEN
Attenuating myostatin enhances striated muscle growth, reduces adiposity, and improves cardiac contractility. To determine whether myostatin influences tissue potency in a manner that could control such pleiotropic actions, we generated label-retaining mice with wild-type and mstn(-/-) (Jekyll) backgrounds in which slow-cycling stem, transit-amplifying, and progenitor cells are preferentially labeled by histone 2B/green fluorescent protein. Jekyll mice were born with fewer label-retaining cells (LRCs) in muscle and heart, consistent with increased stem/progenitor cell contributions to embryonic growth of both tissues. Cardiac LRC recruitment from noncardiac sources occurred in both groups, but lasted longer in Jekyll hearts, whereas heightened ß-adrenergic sensitivity of mstn(-/-) hearts was explained by elevated SERCA2a, phospholamban, and ß2-adrenergic receptor levels. Jekyll mice were also born with more adipose LRCs despite significantly smaller tissue weights. Reduced adiposity in mstn(-/-) animals is therefore due to reduced lipid deposition as adipoprogenitor pools appear to be enhanced. By contrast, increased bone densities of mstn(-/-) mice are likely compensatory to hypermuscularity because LRC counts were similar in Jekyll and wild-type tibia. Myostatin therefore significantly influences the potency of different tissues, not just muscle, as well as cardiac Ca²âº-handling proteins. Thus, the pleiotropic phenotype of mstn(-/-) animals may not be due to enhanced muscle development per se, but also to altered stem/progenitor cell pools that ultimately influence tissue potency.