RNase H2 is a holoenzyme, composed of 3 subunits (ribonuclease H2 subunits A, B, and C), that cleaves RNA:DNA hybrids and removes mis-incorporated ribonucleotides from genomic DNA through ...ribonucleotide excision repair. Ribonucleotide incorporation by eukaryotic DNA polymerases occurs during every round of genome duplication and produces the most frequent type of naturally occurring DNA lesion. We investigated whether intestinal epithelial proliferation requires RNase H2 function and whether RNase H2 activity is disrupted during intestinal carcinogenesis.
We generated mice with epithelial-specific deletion of ribonuclease H2 subunit B (H2bΔIEC) and mice that also had deletion of tumor-suppressor protein p53 (H2b/p53ΔIEC); we compared phenotypes with those of littermate H2bfl/fl or H2b/p53fl/fl (control) mice at young and old ages. Intestinal tissues were collected and analyzed by histology. We isolated epithelial cells, generated intestinal organoids, and performed RNA sequence analyses. Mutation signatures of spontaneous tumors from H2b/p53ΔIEC mice were characterized by exome sequencing. We collected colorectal tumor specimens from 467 patients, measured levels of ribonuclease H2 subunit B, and associated these with patient survival times and transcriptome data.
The H2bΔIEC mice had DNA damage to intestinal epithelial cells and proliferative exhaustion of the intestinal stem cell compartment compared with controls and H2b/p53ΔIEC mice. However, H2b/p53ΔIEC mice spontaneously developed small intestine and colon carcinomas. DNA from these tumors contained T>G base substitutions at GTG trinucleotides. Analyses of transcriptomes of human colorectal tumors associated lower levels of RNase H2 with shorter survival times.
In analyses of mice with disruption of the ribonuclease H2 subunit B gene and colorectal tumors from patients, we provide evidence that RNase H2 functions as a colorectal tumor suppressor. H2b/p53ΔIEC mice can be used to study the roles of RNase H2 in tissue-specific carcinogenesis.
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Secukinumab, a selective interleukin (IL)-17A inhibitor, is approved for use in adult and paediatric psoriasis, psoriatic arthritis, ankylosing spondylitis and non-radiographic axial ...spondyloarthritis. The aim of this study was to report the long-term safety of secukinumab in pooled data from 28 clinical trials and a post-marketing safety surveillance in psoriasis, psoriatic arthritis and ankylosing spondylitis patients. Analyses included 12,637 secukinumab-treated patients, corresponding to 15,063, 5,985 and 3,527 patient-years of exposure in psoriasis, psoriatic arthritis and ankylosing spondylitis patients, respectively. Incidences of serious adverse events were low, with no identifiable patterns across indications. Active tuberculosis or latent tuberculosis infections were rare. The incidence of opportunistic infections was < 0.2/100 patient-years, the incidence of malignancy was ≤ 1/100 patient-years, and the incidence of major adverse cardiovascular events was < 0.7/100 patient-years, with no apparent increases over time. Secukinumab demonstrated a favourable safety profile for up to 5 years of treatment across the 3 indications, and no new safety signals were identified.
Recent rodent microbiome experiments suggest that besides Akkermansia, Parasutterella sp. are important in type 2 diabetes and obesity development. In the present translational human study, we aimed ...to characterize Parasutterella in our European cross-sectional FoCus cohort (n = 1,544) followed by validation of the major results in an independent Canadian cohort (n = 438). In addition, we examined Parasutterella abundance in response to a weight loss intervention (n = 55). Parasutterella was positively associated with BMI and type 2 diabetes independently of the reduced microbiome α/β diversity and low-grade inflammation commonly found in obesity. Nutritional analysis revealed a positive association with the dietary intake of carbohydrates but not with fat or protein consumption. Out of 126 serum metabolites differentially detectable by untargeted HPLC-based MS-metabolomics, L-cysteine showed the strongest reduction in subjects with high Parasutterella abundance. This is of interest, since Parasutterella is a known high L-cysteine consumer and L-cysteine is known to improve blood glucose levels in rodents. Furthermore, metabolic network enrichment analysis identified an association of high Parasutterella abundance with the activation of the human fatty acid biosynthesis pathway suggesting a mechanism for body weight gain. This is supported by a significant reduction of the Parasutterella abundance during our weight loss intervention. Together, these data indicate a role for Parasutterella in human type 2 diabetes and obesity, whereby the link to L-cysteine might be relevant in type 2 diabetes development and the link to the fatty acid biosynthesis pathway for body weight gain in response to a carbohydrate-rich diet in obesity development.
Following up on recent genome-wide association studies (GWAS) of Crohn's disease, we investigated 50 previously reported susceptibility loci in a German sample of individuals with Crohn's disease (n ...= 1,850) or ulcerative colitis (n = 1,103) and healthy controls (n = 1,817). Among these loci, we identified variants in 3p21.31, NKX2-3 and CCNY as susceptibility factors for both diseases, whereas variants in PTPN2, HERC2 and STAT3 were associated only with ulcerative colitis in our sample collection.
Oral therapies targeting the integrin α4β7 may offer unique advantages for the treatment of inflammatory bowel disease. We characterized the oral α4β7 antagonist peptide PTG-100 in preclinical models ...and established safety, pharmacokinetic/pharmacodynamic relationships, and efficacy in a phase 2a trial in patients with ulcerative colitis (UC).
In vitro studies measured binding properties of PTG-100. Mouse studies measured biomarkers and drug concentrations in blood and tissues. The phase 1 study involved healthy volunteers. In phase 2a, patients with moderate to severe active UC were randomized to receive PTG-100 (150, 300, or 900 mg) or placebo once daily for 12-weeks.
PTG-100 potently and selectively blocks α4β7. Oral dosing of PTG-100 in mice showed high levels of target engagement and exposure in gut-associated lymphoid tissues. In healthy volunteers, PTG-100 showed dose-dependent increases in plasma exposure and blood target engagement. Although this phase 2a study initially did not meet the primary endpoint, a blinded reread of the endoscopy videos by a third party indicated clinical efficacy in conjunction with histologic remission at doses correlating with less than 100% receptor occupancy in peripheral blood.
PTG-100 showed local gastrointestinal tissue target engagement and inhibition of memory T-cell trafficking in mice. It was safe and well tolerated in phase 1 and 2 studies. Phase 2a data are consistent with biological and clinical response and showed a dose response reflecting similar activities in preclinical models and healthy individuals. These data suggest that local gut activity of an oral α4β7 integrin antagonist, distinct from full target engagement in blood, are important for efficacy and the treatment of UC. (ClinicalTrials.gov, Number NCT02895100; EudraCT, Number 2016-003452-75)
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PTG-100 shows proof of principle for an oral therapy with limited systemic absorption in patients with ulcerative colitis. PTG-100 was well tolerated in patients with ulcerative colitis.
A 5,000-year-old Yersinia pestis genome (RV 2039) is reconstructed from a hunter-fisher-gatherer (5300–5050 cal BP) buried at Riņņukalns, Latvia. RV 2039 is the first in a series of ancient strains ...that evolved shortly after the split of Y. pestis from its antecessor Y. pseudotuberculosis ∼7,000 years ago. The genomic and phylogenetic characteristics of RV 2039 are consistent with the hypothesis that this very early Y. pestis form was most likely less transmissible and maybe even less virulent than later strains. Our data do not support the scenario of a prehistoric pneumonic plague pandemic, as suggested previously for the Neolithic decline. The geographical and temporal distribution of the few prehistoric Y. pestis cases reported so far is more in agreement with single zoonotic events.
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•Yersinia pestis is discovered in a 5,000-year-old hunter-gatherer from Latvia•Y. pestis emerged ∼7,000 years ago at the beginning of the Neolithic•The infected individual might represent a case of septicemic plague due to zoonosis
Susat et al. reconstruct the genome of a 5,000-year-old Yersinia pestis strain detected in a hunter-gatherer from Latvia. The results show that the basal lineages evolved already at the beginning of the Neolithic and had presumably limited infection potential, suggesting isolated zoonotic events as causative triggers.
Abstract
Background
The Ulcerative Colitis (UC) Narrative global surveys examined patient and physician perspectives on living with UC and tried to identify gaps in optimal care. Questions explored ...patient-physician interactions, UC management goals, and resources for improving communication.
Methods
Questionnaires were conducted across 10 countries, covering aspects of UC including diagnosis, treatment, and impact on patient quality of life, in addition to standard demographic information. Descriptive statistics were calculated.
Results
Globally, 2100 patients and 1254 physicians were surveyed (from August 2017 to February 2018). Results showed 85% of patients were satisfied with the communication they had with their physician, including discussions relating to symptoms (86%) and medication options (81%). However, 72% of patients wished for more information and support at initial diagnosis, and 48% did not feel comfortable talking to their physician about emotional concerns. Most patients (71%) set UC management goals with their physician. Both patients (63%) and physicians (79%) wished for longer appointments. Although 84% of physicians believed patient advocacy organizations to be important in UC management, more than half (54%) never discussed them with patients.
Conclusions
These survey results highlight overall patient satisfaction with patient-physician communication but emphasize areas for improvement, such as patient desire to have more information earlier in their disease course. There is an unmet need for better information, materials, and support. Physicians need to consider which of the available tools and resources can help patients talk more openly, and accurately, because informed patients are more likely to engage with physicians in a shared decision-making process.
Graphical Abstract
Graphical Abstract
RNA synthesis and decay rates determine the steady-state levels of cellular RNAs. Metabolic tagging of newly transcribed RNA by 4-thiouridine (4sU) can reveal the relative contributions of RNA ...synthesis and decay rates. The kinetics of RNA processing, however, had so far remained unresolved. Here, we show that ultrashort 4sU-tagging not only provides snapshot pictures of eukaryotic gene expression but, when combined with progressive 4sU-tagging and RNA-seq, reveals global RNA processing kinetics at nucleotide resolution. Using this method, we identified classes of rapidly and slowly spliced/degraded introns. Interestingly, each class of splicing kinetics was characterized by a distinct association with intron length, gene length, and splice site strength. For a large group of introns, we also observed long lasting retention in the primary transcript, but efficient secondary splicing or degradation at later time points. Finally, we show that processing of most, but not all small nucleolar (sno)RNA-containing introns is remarkably inefficient with the majority of introns being spliced and degraded rather than processed into mature snoRNAs. In summary, our study yields unparalleled insights into the kinetics of RNA processing and provides the tools to study molecular mechanisms of RNA processing and their contribution to the regulation of gene expression.
Molecular danger signals attract neutrophilic granulocytes (polymorphonuclear leukocytes (PMNs)) to sites of infection. The G protein-coupled receptor (GPR) 43 recognizes propionate and butyrate and ...is abundantly expressed on PMNs. The functional role of GPR43 activation for in vivo orchestration of immune response is unclear. We examined dextrane sodium sulfate (DSS)-induced acute and chronic intestinal inflammatory response in wild-type and Gpr43-deficient mice. The severity of colonic inflammation was assessed by clinical signs, histological scoring, and cytokine production. Chemotaxis of wild-type and Gpr43-deficient PMNs was assessed through transwell cell chemotactic assay. A reduced invasion of PMNs and increased mortality due to septic complications were observed in acute DSS colitis. In chronic DSS colitis, Gpr43(-/-) animals showed diminished PMN intestinal migration, but protection against inflammatory tissue destruction. No significant difference in PMN migration and cytokine secretion was detected in a sterile inflammatory model. Ex vivo experiments show that GPR43-induced migration is dependent on activation of the protein kinase p38alpha, and that this signal acts in cooperation with the chemotactic cytokine keratinocyte chemoattractant. Interestingly, shedding of L-selectin in response to propionate and butyrate was compromised in Gpr43(-/-) mice. These results indicate a critical role for GPR43-mediated recruitment of PMNs in containing intestinal bacterial translocation, yet also emphasize the bipotential role of PMNs in mediating tissue destruction in chronic intestinal inflammation.
The marine mussel Mytilus edulis and its closely related sister species are distributed world-wide and play an important role in coastal ecology and economy. The diversification in different species ...and their hybrids, broad ecological distribution, as well as the filter feeding mode of life has made this genus an attractive model to investigate physiological and molecular adaptations and responses to various biotic and abiotic environmental factors. In the present study we investigated the immune system of Mytilus, which may contribute to the ecological plasticity of this species. We generated a large Mytilus transcriptome database from different tissues of immune challenged and stress treated individuals from the Baltic Sea using 454 pyrosequencing. Phylogenetic comparison of orthologous groups of 23 species demonstrated the basal position of lophotrochozoans within protostomes. The investigation of immune related transcripts revealed a complex repertoire of innate recognition receptors and downstream pathway members including transcripts for 27 toll-like receptors and 524 C1q domain containing transcripts. NOD-like receptors on the other hand were absent. We also found evidence for sophisticated TNF, autophagy and apoptosis systems as well as for cytokines. Gill tissue and hemocytes showed highest expression of putative immune related contigs and are promising tissues for further functional studies. Our results partly contrast with findings of a less complex immune repertoire in ecdysozoan and other lophotrochozoan protostomes. We show that bivalves are interesting candidates to investigate the evolution of the immune system from basal metazoans to deuterostomes and protostomes and provide a basis for future molecular work directed to immune system functioning in Mytilus.
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