FORESTACIÓN COMPENSATORIA PROYECTO DE FORESTACION COMPENSATORIA
CRITERIOS DE REFORESTACION
Nuclear remodeling in response to the cytolethal distending toxin: formation of nucleoplasmic reticulum
Azzi-Martin Lamia1,2, Péré-Védrenne Christelle1,2, Alix Chloé1,2, Prochazkova-Carlotti Martina1,2, He Wecan1,2,
Morel Jean-Luc3,4, Grosset Christophe5,6, Varon Christine1,2, Dubus Pierre1,2,7,Ménard Armelle 1,2*
1
INSERM, UMR1053 Bordeaux Research in Translational Oncology, BaRITOn 33076 Bordeaux, France
2
Université de Bordeaux, UMR1053 Bordeaux Research in Translational Oncology, BaRITOn 33076 Bordeaux, France
3
Université de Bordeaux, UMR5293, Institut des maladies neurodégénératives, 33076 Bordeaux, France.
4
CNRS, UMR5293, Institut des maladies neurodégénératives, 33076 Bordeaux, France.
5
INSERM, UMR1035 Biothérapie des Maladies Génétiques, Inflammatoires et Cancers, 33076 Bordeaux, France.
6
University of Bordeaux, Biothérapie des Maladies Génétiques, Inflammatoires et Cancers, 33076 Bordeaux, France.
7
CHU de Bordeaux, Pôle biologie et pathologie, Service de biologie des tumeurs, 33604 Pessac, France.
Cytolethal distending toxin is a widespread secreted-toxin among Gram-negative bacteria. In the present study, we showed that CDT triggers the formation of nuclear invaginations continuous with the endoplasmic reticulum that enclose a cytoplasmic core. These structures, also called nucleoplasmic reticulum, were observed in vivo and in vitro and were particularly important in hepatocytes. They are composed of long tubular channels formed by invaginations of the nuclear envelope, which extend deeply into the nucleoplasm. They contain proteins involved in mRNA translation, polyadenylated RNA and ribosomes. The most important invaginations correlated with giant nuclei having a high degree of ploidy. All these features were not observed during infection with CDT isogenic mutant strains and with other non-CDT toxinogenic bacteria associated to profound reorganization of the cell actin cytoskeleton and stress fiber formation, such as Helicobacter pylori CagA+. The induction of the nuclear invaginations was attributed to the CdtB subunit of the CDT, with a determining role of the histidine residue at position 265 involved in catalytic activity. These CDT-induced invaginations were less important in the presence pharmacological inhibitor targeting the phosphoinositide 3-kinase. These data suggest that CDT induces the presence of ribonucleoprotein particles clustered and invaginated within the nucleus. Such a structure has never been reported during bacterial infections. Its importance in the pathologies associated with CDT remains to be defined, but its role could be associated with the maturation of some mRNAs, their post-transcriptional regulation, their preservation and/or storage in non-translated form.
Investigating Campylobacter jejuni interactions
with endoplasmic reticulum in intestinal epithelial cells resulting in induction of the unfolded protein response.
Gianna Di Sario1, Ozan Gundogdu2, Mahjanah Hussein2, Brendan W. Wren2, Barbara Canonico1, Stefano Papa1,
Abdi Elmi2, Nick Dorrell2
1
Department of Biomolecular Sciences, University of Urbino Carlo Bo,
Urbino, Italy
2
Faculty of Infectious & Tropical Diseases, London School of Hygiene & Tropical Medicine,
London, UK
The Gram-negative bacterium Campylobacter jejuni interacts with, invades and survives within human intestinal epithelial cells (IECs). The endoplasmic reticulum (ER) is a critical organelle involved in multiple physiological functions, yet the extent of how C. jejuni interacts with the ER remains unknown. Our study has shown that C. jejuni interacts with the ER resulting in the activation of the unfolded protein response (UPR), a primitive, evolutionary conserved molecular signalling cascade that has been implicated in multiple biological phenomena including innate immunity and the virulence of bacterial pathogens including Helicobacter pylori, Vibrio cholerae
andShiga-toxigenic Escherichia coli. Our results also demonstrate that C. jejuni induces the UPR in a pathway-specific manner via the inositol-requiring 1α and X-box-binding protein 1 (IRE1α-XBP1) pathway. The C. jejuni cytolethal distending toxin (CDT) appears to have a role in inducing the UPR as both cdtA and cdtB mutants were significantly impaired in the induction of the IRE1α-XBP1 arm of the UPR. This study provides a new conceptual framework for further understanding the role of various C. jejuni virulence factors in the activation of UPRs and opens the way for understanding how C. jejuni diverges from the classical endocytic pathway within IECs, given that induction of the UPR by C. jejuni can lead to autophagic flux in IECs.
Identifying virulence factors that lead to abortion from zoonotic transmission and whole genome sequencing
Weimer Bart, Weis Allison, Clothier Kristen, Huang Carol, Kong Nguyet
UC Davis, School of Veterinary Medicine, 96561 Davis, United States of America
Campylobacter jejuni has emerged as an important cause of abortion in livestock, particularly
small ruminants. This study investigated 17 C. jejuni isolates from clinical abortion cases from sheep, goats, and cows in seven Northern California counties. We hypothesized that a specific allele of as set of virulence genes accounted for the abortive phenotype. Each isolate was subjected to antibiotic resistance profiling, whole genome sequencing, and comparative genomics to determine the relationship between abortive and non-abortive genotypes. Using SMRT sequencing one isolate was sequenced to obtain the closed genome, the methylation density, and methyltransferase complement. The major modification motif was RAATTY with only m6A being found with 99% of the possible sites modified. We observed three distinctly different clades of abortive isolates with three divergent genotypes using genome-to-genome distance calculations. Nearly all isolates (16/17) contained tetO, the tetracycline resistance gene, in the chromosome or on a putative pTet –like plasmid. One isolate was multidrug resistant whose genome contained
tetO, a SNP in gyrA that caused fluoroquinolone resistance, and aphA, an aminoglyscoside
phosphotransferase conferring kanamycin resistance. It is reported that porA is responsible for abortion in model organisms. In this study, porA was divergent among abortive isolates and did not predict livestock abortion. Other adhesion factors (jlpA, pebA, and cadF) were associated livestock abortion, but were not allelically identical. The toxin gene, cdtC, was identical in every abortive isolate, but different as compared to non-abortive isolates. This study demonstrated that cdtC was predictive of livestock abortion.
Insights into Campylobacter jejuni colonization and enteritis using a novel infant rabbit model
Fangzhe Ren1, Yuwei Shang 1, Zhaojun Song1, Qiuchun Li1, Xiaohui Zhou2, Xiaobo Wang3, Zhonglan Xu4, Guangyu Bao5, Ting Wan1, Tianyao Lei1, Nan Wang1, Xin-an Jiao1, Jinlin Huang1
1
Jiangsu Key Lab of Zoonosis, Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses,
Yangzhou University, Yangzhou 225009, China.
2
Department of Pathobiology and Veterinary Science, the University of Connecticut, Storrs 06269, United States of America.
3
College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China.
4
Yangzhou Maternity and Infant Hospital, Yangzhou 225001, China.
5
Yangzhou First People’s Hospital, Yangzhou 225004, China.
A lack of relevant disease models for Campylobacter jejuni has long been an obstacle to research into this common enteric pathogen. Here we used an infant rabbit to study C. jejuni infection, which enables us to define several previously unknown but key features of the organism. C. jejuni is capable of systemic invasion in the rabbit, and developed a diarrhea symptom that mimicked that observed in many human campylobacteriosis. The large intestine was the most consistently colonized site and produced intestinal inflammation, where specific cytokines were induced. Genes preferentially expressed during C. jejuni infection were screened, and acs, cj1385, cj0259 seem to be responsible for C. jejuni invasion. Our results demonstrates that the infant rabbit can be used as an alternative experimental model for the study of diarrheagenic Campylobacter species and will be useful in exploring the pathogenesis of other related pathogens.
Gastric cancer-associated polymorphisms
in the Helicobacter pylori type IV secretion system protein CagL: a potential biomarker for cancer risk
Gorrell Rebecca 1,2,3, Alyahiwi Hanan 1,2, Zwickel Nicolas 1,2, Reynolds John 4,5, Bulach Dieter 6, Kwok Terry 1,2,3
1
Infection and Immunity, and Cancer Programs, Monash Biomedicine Discovery Institute,
2
Department of Biochemistry and Molecular Biology
3
Department of Microbiology, Monash University, Clayton, Australia
4
Biostatistics Consulting Platform, Faculty of Medicine, Nursing and Health Sciences, Monash University, The Alfred Centre, Melbourne, Australia
5
Clinical Hematology, The Alfred, Prahran, Australia
6
Victorian Bioinformatics Consortium, Monash University, Australia.
The Helicobacter pylori CagL protein is essential for translocation of the oncogenic CagA protein into human cells. CagL is a key component of the cag pathogenicity island-encoded type IV secretion system. Previous studies suggest overrepresentation of particular polymorphisms within the 5-residue long CagL hypervariable motif (CagLHM) in H. pylori isolates from gastric cancer patients. However, these disease correlations were geographically variable and ambiguous. We compared the disease correlation of several hundred geographically diverse CagL sequences and identified >35 CagLHM sequence combinations with disparate geographical distribution, revealing substantial worldwide CagLHM diversity, particularly within Asian countries. Importantly, we discovered that certain CagLHM sequence polymorphisms correlate significantly with increased gastric cancer risks in H. pylori-infected patients. These associations were consistent across isolates from both Asian and non-Asian countries despite substantial sequence diversity of CagLHM across the globe. Thus, CagLHM regional diversity may contribute to the varied prevalence of H. pylori-related gastric cancer observed in diverse populations. These exciting findings point to the tantalising notion that CagL is a novel biomarker for early diagnosis of gastric cancer and a ‘molecular beacon’ for identifying key host factors and signaling pathways that underpin the pathogenesis of H. pylori-induced gastric cancer.
Helicobacter pylori expands and functionally activates
a novel gastric stem cell population in a cag pathogenicity island-dependent manner
Wroblewski Lydia E.1, Romero-Gallo Judith1, Goldenring James R.2, Coffey Robert J. 2, Amieva Manuel R. 3, Powell Anne E. 4, Peek Jr. Richard M. 1
1
Division of Gastroenterology, Hepatology, and Nutrition, Department of Medicine, Vanderbilt University Medical Center,
Nashville, TN, USA
2
Department of Cell and Developmental Biology, Vanderbilt University, School of Medicine, Nashville, TN, USA
3
Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
4
Institute of Molecular Biology, University of Oregon, Eugene, OR, USA
The H. pylori cag pathogenicity island is a strain-specific constituent that induces epithelial responses with carcinogenic potential. Within the gastric epithelium, stem cells are critical for regulating self-renewal and maintaining tissue homeostasis. Lrig1 (Leucine-rich repeats and immunoglobulin-like domains 1) marks a distinct population of gastric stem cells. The aim of this study was to determine whether the cag pathogenicity island mediates Lrig1 stem cell activity and concomitant expansion within H. pylori-infected gastric mucosa. Lineage tracing was induced in six-week-old Lrig1-CreERT2/+;R26R-YFP/+ mice; one week later, mice were infected with broth alone (control), the cag+ H. pylori strain PMSS1, or a PMSS1 cagE- isogenicmutant, and sacrificed 2- and 8 weeks post-challenge. There were no differences in colonization efficiency or density between infected groups. Infection with wild-type PMSS1 for 8 weeks, but not 2 weeks, resulted in significantly (pd0.05) increased inflammation and epithelial proliferation compared to uninfected controls or the cagE- mutant. Similarly, mice infected with wild-type H. pylori for 8 weeks, but not 2 weeks, harbored a significantly higher number of Lrig1-derived lineage traced glands, reflecting enhanced Lrig1 stem cell activity (uninfected=93 labeled glands, PMSS1=140 labeled glands,
cagE=86.7 labeled glands; per 5 m section of gastric corpus, pd0.05). Based on these findings, we
subsequently generated gastric organoids and determined that, similar to in vivo findings, significantly (p<0.05) more organoids developed from mice infected with PMSS1 compared with controls or the cagE- mutant, reflecting increased stem cell activity. Using markers of metaplasia (GSII lectin) and surface mucus cells (UEA1) in combination with lineage tracing, we determined that Lrig1-traced cells generated metaplastic and surface cells. In conclusion, H. pylori induces expansion of Lrig1+ cells and stimulates Lrig1 progenitor cell activity in a cag-dependent manner within an inflammatory milieu. These data identify cag-dependent signaling as a key mediator of epithelial stem cell function following infection by H. pylori.