Comprehensive analysis of circular RNAs in porcine small intestine epithelial cells associated with susceptibility to Escherichia coli F4ac diarrhea.

BACKGROUND: Diarrhea is one of the most common diseases in pig industry, which seriously threatens the health of piglets and causes huge economic losses. Enterotoxigenic Escherichia coli (ETEC) F4 is regarded as the most important cause of diarrhea in piglets. Some pigs are naturally resistant to those diarrheas caused by ETEC-F4, because they have no F4 receptors (F4R) on their small intestine epithelial cells that allow F4 fimbriae adhesion. Circular RNA (circRNA) has been shown to play an important regulatory role in the pathogenesis of disease. We hypothesized that circRNAs may also regulate the adhesion of piglet small intestinal epithelial cells to ETEC F4 fimbriae. However, the circRNA expression profiles of piglets with different Enterotoxigenic Escherichia coli F4 fimbriae (ETEC-F4ac) adhesion phenotypes are still unclear, and the intermediate regulatory mechanisms need to be explored. Hence, the present study assessed the circRNA expression profiling in small intestine epithelial cells of eight male piglets with different ETEC-F4 adhesion phenotypes and ITGB5 genotypes to unravel their regulatory function in susceptibility to ETEC-F4ac diarrhea. Piglets were divided into two groups: non-adhesive group (n = 4) with CC genotype and adhesive group (n = 4) with TT genotype. RESULTS: The RNA-seq data analysis identified 13,199 circRNAs from eight samples, most of which were exon-derived. In the small intestine epithelial cells, 305 were differentially expressed (DE) circRNAs between the adhesive and non-adhesive groups; of which 46 circRNAs were upregulated, and 259 were downregulated. Gene ontology and KEGG enrichment analysis revealed that most significantly enriched DE circRNAs' host genes were linked to cytoskeletal components, protein phosphorylation, cell adhesion, ion transport and pathways (such as adherens junction, gap junction) associated with ETEC diarrhea. The circRNA-miRNA-mRNA interaction network was also constructed to elucidate their underlying regulatory relationships. Our results identified several candidate circRNAs that affects susceptibility to ETEC diarrhea. Among them, circ-SORBS1 can adsorb ssc-miR-345-3p to regulate the expression of its host gene SORBS1, thus improving cell adhesion. CONCLUSION: Our results provided insights into the regulation function of circRNAs in susceptibility to ETEC diarrhea of piglets, and enhanced our understanding of the role of circRNAs in regulating ETEC diarrhea, and reveal the great potential of circRNA as a diagnostic marker for susceptibility of ETEC diarrhea in piglets.

Análisis retrospectivo de perfil microbiológico y resistencia antimicrobiana en infección urinaria pediátrica de hospitales públicos de Quito-Ecuador

Objetivo: Determinar el perfil microbiológico y resistencia antimicrobiana en infección urinaria en niños. Materiales y métodos: Estudio descriptivo, transversal, observacional y multicéntrico. Se estudiaron 445 urocultivos procesados y los resultados de antibiogramas en tres hospitales públicos de Quito (Ecuador). En relación con los agentes causales se establecieron frecuencias absolutas y proporciones. En el análisis bivariable entre el antecedente de malformación renal o de la vía urinaria y el riesgo de infección, se aplicó el test Chi2 (p < 0,05) y la RP [IC 95 %; p < 0,05]. Resultados: Se evidenció una resistencia ante aminopenicilinas del 73,5 %; ampicilina más sulbactam 31,8 %; trimetoprim-sulfametoxazol 55,5 %; cefalosporinas de primera y segunda generación hasta 33 %; cefalosporinas de tercera y cuarta generación del 21,3 al 47 %. Ante malformación urinaria y aislamiento de bacterias diferentes a Escherichia coli, se identificó a Klebsiella pneumoniae RP 2,66 [IC 95 %, 1,9-3,6; p < 0,05] y Pseudomonas aeruginosa RP 2,07 [IC 95 %, 1,2-3,5; p < 0,05]. Conclusiones: En nuestro medio, ante el diagnóstico de infección urinaria, no parece adecuado iniciar tratamiento antibiótico con aminopenicilinas, trimetoprim-sulfametoxazol ni cefalosporinas de primera a cuarta generaciones por su elevada resistencia. La presencia de malformación urinaria se asocia a infección por bacterias diferentes de Escherichia coli.

Objective: Determine the microbiological profile and antimicrobial susceptibility in urinary infection in children. Materials and methods: Descriptive, cross-sectional, observational, and multicenter study. 445 urine cultures and the results of antibiograms were studied in three public hospitals in Quito (Ecuador). In relation to the causal agents, absolute frequencies and proportions were established. In the bivariate analysis, Chi-squared test (p < 0.05) and PR [CI 95 %; p < 0.05] were applied between history of kidney or urinary tract malformation and risk of infection. Results: There was evidence of resistance to aminopenicillins of 73.5 %; ampicillin plus sulbactam 31.8 %; trimethoprim-sulfamethoxazole 55.5 %; first and second generation cephalosporins up to 33 %; resistance to third and fourth generation cephalosporins from 21.3 to 47%. In relation to urinary malformation and the isolate of a bacteria different from Escherichia coli, Klebsiella pneumoniae PR 2,66 [CI 95 %, 1.9-3.6; p < 0.05] and Pseudomonas aeruginosa PR 2.07 [CI 95 %, 1.2-3.5; p < 0.05] were identified. Conclusions: In our locality it wouldn't be appropriate to start antibiotic treatment with aminopenicillins, trimethoprim-sulfamethoxazole or first to fourth generation cephalosporins in urinary tract infection due to their resistance. The presence of urinary malformation is associated with infection by bacteria other than Escherichia coli.

Beyond the genomes of Fulvia fulva (syn. Cladosporium fulvum) and Dothistroma septosporum: New insights into how these fungal pathogens interact with their host plants.

Fulvia fulva and Dothistroma septosporum are closely related apoplastic pathogens with similar lifestyles but different hosts: F. fulva is a pathogen of tomato, whilst D. septosporum is a pathogen of pine trees. In 2012, the first genome sequences of these pathogens were published, with F. fulva and D. septosporum having highly fragmented and near-complete assemblies, respectively. Since then, significant advances have been made in unravelling their genome architectures. For instance, the genome of F. fulva has now been assembled into 14 chromosomes, 13 of which have synteny with the 14 chromosomes of D. septosporum, suggesting these pathogens are even more closely related than originally thought. Considerable advances have also been made in the identification and functional characterization of virulence factors (e.g., effector proteins and secondary metabolites) from these pathogens, thereby providing new insights into how they promote host colonization or activate plant defence responses. For example, it has now been established that effector proteins from both F. fulva and D. septosporum interact with cell-surface immune receptors and co-receptors to activate the plant immune system. Progress has also been made in understanding how F. fulva and D. septosporum have evolved with their host plants, whilst intensive research into pandemics of Dothistroma needle blight in the Northern Hemisphere has shed light on the origins, migration, and genetic diversity of the global D. septosporum population. In this review, we specifically summarize advances made in our understanding of the F. fulva-tomato and D. septosporum-pine pathosystems over the last 10 years.

Recognition of Multiple Hybrid Insulin Peptides by a Single Highly Diabetogenic T-Cell Receptor.

The mechanisms underlying the major histocompatibility complex class II (MHCII) type 1 diabetes (T1D) association remain incompletely understood. We have previously shown that thymocytes expressing the highly diabetogenic, I-Ag7-restricted 4.1-T-cell receptor (TCR) are MHCII-promiscuous, and that, in MHCII-heterozygous mice, they sequentially undergo positive and negative selection/Treg deviation by recognizing pro- and anti-diabetogenic MHCII molecules on cortical thymic epithelial cells and medullary hematopoietic antigen-presenting cells (APCs), respectively. Here, we use a novel autoantigen discovery approach to define the antigenic specificity of this TCR in the context of I-Ag7. This was done by screening the ability of random epitope-GS linker-I- Aßg7 chain fusion pools to form agonistic peptide-MHCII complexes on the surface of I- Aαd chain-transgenic artificial APCs. Pool deconvolution, I-Ag7-binding register-fixing, TCR contact residue mapping, and alanine scanning mutagenesis resulted in the identification of a 4.1-TCR recognition motif XL(G/A)XEXE(D/E)X that was shared by seven agonistic hybrid insulin peptides (HIPs) resulting from the fusion of several different chromogranin A and/or insulin C fragments, including post-translationally modified variants. These data validate a novel, highly sensitive MHCII-restricted epitope discovery approach for orphan TCRs and suggest thymic selection of autoantigen-promiscuous TCRs as a mechanism for the murine T1D-I-Ag7-association.

ABO Blood Group Incompatibility Protects Against SARS-CoV-2 Transmission.

ABO blood groups appear to be associated with the risk of SARS-CoV-2 infection, but the underlying mechanisms and their real importance remain unclear. Two hypotheses have been proposed: ABO compatibility-dependence (neutralization by anti-ABO antibodies) and ABO-dependent intrinsic susceptibility (spike protein attachment to histo-blood group glycans). We tested the first hypothesis through an anonymous questionnaire addressed to hospital staff members. We estimated symptomatic secondary attack rates (SAR) for 333 index cases according to spouse ABO blood group compatibility. Incompatibility was associated with a lower SAR (28% vs. 47%; OR 0.43, 95% CI 0.27-0.69), but no ABO dependence was detected in compatible situations. For the second hypothesis, we detected no binding of recombinant SARS-CoV-2 RBD to blood group-containing glycans. Thus, although no intrinsic differences in susceptibility according to ABO blood type were detected, ABO incompatibility strongly decreased the risk of COVID-19 transmission, suggesting that anti-ABO antibodies contribute to virus neutralization.

Functional prediction and comparative population analysis of variants in genes for proteases and innate immunity related to SARS-CoV-2 infection.

New coronavirus SARS-CoV-2 is capable to infect humans and cause a novel disease COVID-19. Aiming to understand a host genetic component of COVID-19, we focused on variants in genes encoding proteases and genes involved in innate immunity that could be important for susceptibility and resistance to SARS-CoV-2 infection. Analysis of sequence data of coding regions of FURIN, PLG, PRSS1, TMPRSS11a, MBL2 and OAS1 genes in 143 unrelated individuals from Serbian population identified 22 variants with potential functional effect. In silico analyses (PolyPhen-2, SIFT, MutPred2 and Swiss-Pdb Viewer) predicted that 10 variants could impact the structure and/or function of proteins. These protein-altering variants (p.Gly146Ser in FURIN; p.Arg261His and p.Ala494Val in PLG; p.Asn54Lys in PRSS1; p.Arg52Cys, p.Gly54Asp and p.Gly57Glu in MBL2; p.Arg47Gln, p.Ile99Val and p.Arg130His in OAS1) may have predictive value for inter-individual differences in the response to the SARS-CoV-2 infection. Next, we performed comparative population analysis for the same variants using extracted data from the 1000 Genomes project. Population genetic variability was assessed using delta MAF and Fst statistics. Our study pointed to 7 variants in PLG, TMPRSS11a, MBL2 and OAS1 genes with noticeable divergence in allelic frequencies between populations worldwide. Three of them, all in MBL2 gene, were predicted to be damaging, making them the most promising population-specific markers related to SARS-CoV-2 infection. Comparing allelic frequencies between Serbian and other populations, we found that the highest level of genetic divergence related to selected loci was observed with African, followed by East Asian, Central and South American and South Asian populations. When compared with European populations, the highest divergence was observed with Italian population. In conclusion, we identified 4 variants in genes encoding proteases (FURIN, PLG and PRSS1) and 6 in genes involved in the innate immunity (MBL2 and OAS1) that might be relevant for the host response to SARS-CoV-2 infection.