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84 result(s) for "Guo, Lydia"
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PD-L1+ and XCR1+ dendritic cells are region-specific regulators of gut homeostasis
The intestinal mucosa constitutes an environment of closely regulated immune cells. Dendritic cells (DC) interact with the gut microbiome and antigens and are important in maintaining gut homeostasis. Here, we investigate DC transcriptome, phenotype and function in five anatomical locations of the gut lamina propria (LP) which constitute different antigenic environments. We show that DC from distinct gut LP compartments induce distinct T cell differentiation and cytokine secretion. We also find that PD-L1 + DC in the duodenal LP and XCR1 + DC in the colonic LP comprise distinct tolerogenic DC subsets that are crucial for gut homeostasis. Mice lacking PD-L1 + and XCR1 + DC have a proinflammatory gut milieu associated with an increase in Th1/Th17 cells and a decrease in Treg cells and have exacerbated disease in the models of 5-FU-induced mucositis and DSS-induced colitis. Our findings identify PD-L1 + and XCR1 + DC as region-specific physiologic regulators of intestinal homeostasis. Dendritic cells initiate and regulate adaptive immunity and differ according to gut anatomical location. Here the authors show that DC residing in the upper and lower intestines show differential PD-L1 and XCR1 expression and drive specific T cell responses to prevent gut inflammation.
Transcriptomic analysis identifies a potential target for bevacizumab resistant glioblastoma
Glioblastoma, IDH wild-type (WHO grade 4) (GBM), is the most common primary brain tumor in adults with a 21-month median overall survival, despite surgical-resection and radio-chemotherapy. Bevacizumab, a monoclonal antibody towards vascular endothelial growth factor-A, is used to treat recurrent-GBM. To find predictors of poor-response, patient-derived xenograft (PDX)-tumors were treated with bevacizumab or vehicle and subsequently grouped based on survival-response; RNAseq expression was then compared by responder-status. Bioinformatic-analysis demonstrated differential gene expression in tumors from poor-responders (six-PDXs) as compared to tumors from good-responders (three-PDXs), along with upregulation of angiogenesis and collagen gene-sets in poor-responders. Within these gene-sets, multiple genes known to be regulated by the early growth response-1 (EGR1) transcription factor, which was also upregulated, were identified and CHRNA7 (α7-nicotinic-acetylcholine receptor, α7-nAChR) was selected for validation. In terms of protein/functional studies, in the bevacizumab-treated poor-responders, nuclear-EGR1 was elevated, Ki67-labeling was increased in EGR1 high tumor, and there was increased angiogenesis. Expression of α7-nAChR and nuclear EGR1 was directly correlated, suggesting CHRNA7 is an EGR1 downstream target. Data-mining (GLASS-database) showed that recurrent GBM in females with an elevated EGR1 and methylated MGMT promoter had a shorter survival. In summary, GBM with increased EGR1 expression, Ki67-labeling in EGR1 high tumor and angiogenesis demonstrated a poor-response to bevacizumab, suggesting EGR1 could be useful in predicting response.
Ferret models of alpha-1 antitrypsin deficiency develop lung and liver disease
Alpha-1 antitrypsin deficiency (AATD) is the most common genetic cause and risk factor for chronic obstructive pulmonary disease, but the field lacks a large-animal model that allows for longitudinal assessment of pulmonary function. We hypothesized that ferrets would model human AATD-related lung and hepatic disease. AAT-knockout (AAT-KO) and PiZZ (E342K, the most common mutation in humans) ferrets were generated and compared with matched controls using custom-designed flexiVent modules to perform pulmonary function tests, quantitative computed tomography (QCT), bronchoalveolar lavage (BAL) proteomics, and alveolar morphometry. Complete loss of AAT (AAT-KO) led to increased pulmonary compliance and expiratory airflow limitation, consistent with obstructive lung disease. QCT and morphometry confirmed emphysema and airspace enlargement, respectively. Pathway analysis of BAL proteomics data revealed inflammatory lung disease and impaired cellular migration. The PiZ mutation resulted in altered AAT protein folding in the liver, hepatic injury, and reduced plasma concentrations of AAT, and PiZZ ferrets developed obstructive lung disease. In summary, AAT-KO and PiZZ ferrets model the progressive obstructive pulmonary disease seen in AAT-deficient patients and may serve as a platform for preclinical testing of therapeutics including gene therapy.
Gamma-delta T cells modulate the microbiota and fecal micro-RNAs to maintain mucosal tolerance
Background Gamma-delta (γδ) T cells are a major cell population in the intestinal mucosa and are key mediators of mucosal tolerance and microbiota composition. Little is known about the mechanisms by which intestinal γδ T cells interact with the gut microbiota to maintain tolerance. Results We found that antibiotic treatment impaired oral tolerance and depleted intestinal γδ T cells, suggesting that the gut microbiota is necessary to maintain γδ T cells. We also found that mice deficient for γδ T cells (γδ −/− ) had an altered microbiota composition that led to small intestine (SI) immune dysregulation and impaired tolerance. Accordingly, colonizing WT mice with γδ −/− microbiota resulted in SI immune dysregulation and loss of tolerance whereas colonizing γδ −/− mice with WT microbiota normalized mucosal immune responses and restored mucosal tolerance. Moreover, we found that SI γδ T cells shaped the gut microbiota and regulated intestinal homeostasis by secreting the fecal micro-RNA let-7f. Importantly, oral administration of let-7f to γδ −/− mice rescued mucosal tolerance by promoting the growth of the γδ −/− -microbiota-depleted microbe Ruminococcus gnavus . Conclusions Taken together, we demonstrate that γδ T cell-selected microbiota is necessary and sufficient to promote mucosal tolerance, is mediated in part by γδ T cell secretion of fecal micro-RNAs, and is mechanistically linked to restoration of mucosal immune responses. D2yzZ8iEUhaZXKXDSGKikq Video Abstract
In utero and postnatal ivacaftor/lumacaftor therapy rescues multiorgan disease in CFTR-F508del ferrets
Cystic fibrosis (CF) is caused by mutations in the CF transmembrane conductance regulator (CFTR) gene, with F508del being the most prevalent mutation. The combination of CFTR modulators (potentiator and correctors) has provided benefit to CF patients carrying the F508del mutation; however, the safety and effectiveness of in utero combination modulator therapy remains unclear. We created a F508del ferret model to test whether ivacaftor/lumacaftor (VX-770/VX-809) therapy can rescue in utero and postnatal pathologies associated with CF. Using primary intestinal organoids and air-liquid interface cultures of airway epithelia, we demonstrate that the F508del mutation in ferret CFTR results in a severe folding and trafficking defect, which can be partially restored by treatment with CFTR modulators. In utero treatment of pregnant jills with ivacaftor/lumacaftor prevented meconium ileus at birth in F508del kits and sustained postnatal treatment of CF offspring improved survival and partially protected from pancreatic insufficiency. Withdrawal of ivacaftor/lumacaftor treatment from juvenile CF ferrets reestablished pancreatic and lung diseases, with altered pulmonary mechanics. These findings suggest that in utero intervention with a combination of CFTR modulators may provide therapeutic benefits to individuals with F508del. This CFTR-F508del ferret model may be useful for testing therapies using clinically translatable endpoints.
Proliferation is the strongest prognosticator in node-negative breast cancer: significance, error sources, alternatives and comparison with molecular prognostic markers
Independent studies have shown that in node negative breast cancer patients less than 71 years, the proliferation marker mitotic activity index (MAI) is the strongest, most well reproducible prognosticator and chemotherapy success predictor. The MAI overshadows the prognostic value of tubule formation, nuclear atypia and thereby grade. An often used crude mitotic impression is much less prognostic than the MAI; strict adherence to the MAI protocol is therefore important. The prognostic value of the MAI is age dependent: although patients with a MAI >= 10 always have a poor prognosis irrespective of age, a low MAI (<10) loses its favourable prognostic association in women >70 years. PPH3 counts are prognostically stronger than the MAI, and markers such as Cyclin-B and E2FR are promising, but must be validated. Compared with commercial prognostic gene expression signatures, the MAI is at least as strong prognostically, has far fewer false positive results and as such should be included as an independent feature in any node negative breast cancer pathology report.
Identification of environmental factors that promote intestinal inflammation
Genome-wide association studies have identified risk loci linked to inflammatory bowel disease (IBD) 1 —a complex chronic inflammatory disorder of the gastrointestinal tract. The increasing prevalence of IBD in industrialized countries and the augmented disease risk observed in migrants who move into areas of higher disease prevalence suggest that environmental factors are also important determinants of IBD susceptibility and severity 2 . However, the identification of environmental factors relevant to IBD and the mechanisms by which they influence disease has been hampered by the lack of platforms for their systematic investigation. Here we describe an integrated systems approach, combining publicly available databases, zebrafish chemical screens, machine learning and mouse preclinical models to identify environmental factors that control intestinal inflammation. This approach established that the herbicide propyzamide increases inflammation in the small and large intestine. Moreover, we show that an AHR–NF-κB–C/EBPβ signalling axis operates in T cells and dendritic cells to promote intestinal inflammation, and is targeted by propyzamide. In conclusion, we developed a pipeline for the identification of environmental factors and mechanisms of pathogenesis in IBD and, potentially, other inflammatory diseases. The herbicide propyzamide increases inflammation in the small and large intestine, and the AHR–NF-κB–C/EBPβ signalling axis—which operates in T cells and dendritic cells to promote intestinal inflammation—is targeted by propyzamide.
Tumor-related epilepsy in high-grade glioma: a large series survival analysis
Purpose Seizures are a common clinical occurrence in high-grade glioma (HGG). While many studies have explored seizure incidence and prevalence in HGG, limited studies have examined the prognostic effect of seizures occurring in the post-diagnosis setting. This study aims to assess the impact of seizure presentation on HGG survival outcomes. Methods Single-center retrospective review identified 950 patients with histologically-confirmed high-grade glioma. Seizure presentation was determined by clinical history and classified as early onset (occurring within 30 days of HGG presentation) or late onset (first seizure occurring after beginning HGG treatment). The primary outcome, hazard ratios for overall survival and progression-free survival, was assessed with multivariable Cox proportional-hazards models. IDH1 mutation status (assessed through immunohistochemistry) was only consistently available beginning in 2015; subgroup analyses were performed in the subset of patients with known IDH1 status. Results Epileptic activity before (HR = 0.81, 95% CI = 0.68–0.96, P  = 0.017) or after (HR = 0.74, 95% CI = 0.60–0.91, P  = 0.005) HGG diagnosis associated with improved overall survival. Additionally, late seizure onset significantly associated with lower odds of achieving partial (OR = 0.25, 95% CI = 0.12–0.53, P = < 0.001) or complete (OR = 0.30, 95% CI = 0.18–0.50, P  < 0.001) seizure control than patients with early seizure onset. Conclusions Clinical seizures both at the time of diagnosis and later during the HGG treatment course are associated with improved overall survival. This association potentially persists for both IDH1 -wildtype and IDH1- mutant patients, but further study is required.
Enabling precision medicine via standard communication of HTS provenance, analysis, and results
A personalized approach based on a patient's or pathogen's unique genomic sequence is the foundation of precision medicine. Genomic findings must be robust and reproducible, and experimental data capture should adhere to findable, accessible, interoperable, and reusable (FAIR) guiding principles. Moreover, effective precision medicine requires standardized reporting that extends beyond wet-lab procedures to computational methods. The BioCompute framework (https://w3id.org/biocompute/1.3.0) enables standardized reporting of genomic sequence data provenance, including provenance domain, usability domain, execution domain, verification kit, and error domain. This framework facilitates communication and promotes interoperability. Bioinformatics computation instances that employ the BioCompute framework are easily relayed, repeated if needed, and compared by scientists, regulators, test developers, and clinicians. Easing the burden of performing the aforementioned tasks greatly extends the range of practical application. Large clinical trials, precision medicine, and regulatory submissions require a set of agreed upon standards that ensures efficient communication and documentation of genomic analyses. The BioCompute paradigm and the resulting BioCompute Objects (BCOs) offer that standard and are freely accessible as a GitHub organization (https://github.com/biocompute-objects) following the \"Open-Stand.org principles for collaborative open standards development.\" With high-throughput sequencing (HTS) studies communicated using a BCO, regulatory agencies (e.g., Food and Drug Administration [FDA]), diagnostic test developers, researchers, and clinicians can expand collaboration to drive innovation in precision medicine, potentially decreasing the time and cost associated with next-generation sequencing workflow exchange, reporting, and regulatory reviews.