Predicting the Next Superspreader.

The spread of multidrug-resistant zoonotic pathogens, such as Salmonella, within livestock is of concern for food safety. The spread of Salmonella on the farm is escalated by superspreaders, which shed the pathogen at high numbers with their feces. However, there are currently no biomarkers to identify potential superspreaders. Kempf and coworkers determined that a potent early inflammatory response to Salmonella infection and changes in the microbiota composition are associated with the superspreader phenotype in pigs (F. Kempf, G. Cordoni, A.M. Chaussé, R. Drumo, et al., mSystems, in press, https://doi.org/10.1128/msystems.00852-22). Since these biomarkers only develop during Salmonella infection, additional work is needed to predict animals that have the potential to become superspreaders.

Cytoskeletal dynamics regulates stromal invasion behavior of distinct liver cancer subtypes.

Drug treatment against liver cancer has limited efficacy due to heterogeneous response among liver cancer subtypes. In addition, the functional biophysical phenotypes which arise from this heterogeneity and contribute to aggressive invasive behavior remain poorly understood. This study interrogated how heterogeneity in liver cancer subtypes contributes to differences in invasive phenotypes and drug response. Utilizing histological analysis, quantitative 2D invasion metrics, reconstituted 3D hydrogels, and bioinformatics, our study linked cytoskeletal dynamics to differential invasion profiles and drug resistance in liver cancer subtypes. We investigated cytoskeletal regulation in 2D and 3D culture environments using two liver cancer cell lines, SNU-475 and HepG2, chosen for their distinct cytoskeletal features and invasion profiles. For SNU-475 cells, a model for aggressive liver cancer, many cytoskeletal inhibitors abrogated 2D migration but only some suppressed 3D migration. For HepG2 cells, cytoskeletal inhibition did not significantly affect 3D migration but did affect proliferative capabilities and spheroid core growth. This study highlights cytoskeleton driven phenotypic variation, their consequences and coexistence within the same tumor, as well as efficacy of targeting biophysical phenotypes that may be masked in traditional screens against tumor growth.

Non-adaptive evolutionary processes governed the diversification of a temperate conifer lineage after its migration into the tropics.

Constructing phylogenetic relationships among closely related species is a recurrent challenge in evolutionary biology, particularly for long-lived taxa with large effective population sizes and uncomplete reproductive isolation, like conifers. Conifers further have slow evolutionary rates, which raises the question of whether adaptive or non/adaptive processes were predominantly involved when they rapidly diversified after migrating from temperate regions into the tropical mountains. Indeed, fine-scale phylogenetic relationships within several conifer genus remain under debate. Here, we studied the phylogenetic relationships of endemic firs (Abies, Pinaceae) discontinuously distributed in the montane forests from the Southwestern United States to Guatemala, and addressed several hypotheses related to adaptive and non-adaptive radiations. We derived over 80 K SNPs from genotyping by sequencing (GBS) for 45 individuals of nine Mesoamerican species to perform phylogenetic analyses. Both Maximum Likelihood and quartets-inference phylogenies resulted in a well-resolved topology, showing a single fir lineage divided in four subgroups that coincided with the main mountain ranges of Mesoamerica; thus having important taxonomic implications. Such subdivision fitted a North-South isolation by distance framework, in which non-adaptive allopatric processes seemed the rule. Interestingly, several reticulations were observed within subgroups, especially in the central-south region, which may explain past difficulties for generating infrageneric phylogenies. Further evidence for non-adaptive processes was obtained from analyses of 21 candidate-gene regions, which exhibited diminishing values of πa/πs and Ka/Ks with latitude, thus indicating reduced efficiency of purifying selection towards the Equator. Our study indicates that non-adaptive allopatric processes may be key generators of species diversity and endemism in the tropics.

TLR2 and endosomal TLR-mediated secretion of IL-10 and immune suppression in response to phagosome-confined Listeria monocytogenes.

Listeria monocytogenes is a facultative intracellular bacterial pathogen that escapes from phagosomes and induces a robust adaptive immune response in mice, while mutants unable to escape phagosomes fail to induce a robust adaptive immune response and suppress the immunity to wildtype bacteria when co-administered. The capacity to suppress immunity can be reversed by blocking IL-10. In this study, we sought to understand the host receptors that lead to secretion of IL-10 in response to phagosome-confined L. monocytogenes (Δhly), with the ultimate goal of generating strains that fail to induce IL-10. We conducted a transposon screen to identify Δhly L. monocytogenes mutants that induced significantly more or less IL-10 secretion in bone marrow-derived macrophages (BMMs). A transposon insertion in lgt, which encodes phosphatidylglycerol-prolipoprotein diacylglyceryl transferase and is essential for the formation of lipoproteins, induced significantly reduced IL-10 secretion. Mutants with transposon insertions in pgdA and oatA, which encode peptidoglycan N-acetylglucosamine deacetylase and O-acetyltransferase, are sensitive to lysozyme and induced enhanced IL-10 secretion. A ΔhlyΔpgdAΔoatA strain was killed in BMMs and induced enhanced IL-10 secretion that was dependent on Unc93b1, a trafficking molecule required for signaling of nucleic acid-sensing TLRs. These data revealed that nucleic acids released by bacteriolysis triggered endosomal TLR-mediated IL-10 secretion. Secretion of IL-10 in response to infection with the parental strain was mostly TLR2-dependent, while IL-10 secretion in response to lysozyme-sensitive strains was dependent on TLR2 and Unc93b1. In mice, the IL-10 response to vacuole-confined L. monocytogenes was also dependent on TLR2 and Unc93b1. Co-administration of Δhly and ΔactA resulted in suppressed immunity in WT mice, but not in mice with mutations in Unc93b1. These data revealed that secretion of IL-10 in response to L. monocytogenes infection in vitro is mostly TLR2-dependent and immune suppression by phagosome-confined bacteria in vivo is mostly dependent on endosomal TLRs.

Calpain inhibitor and ibudilast rescue ß cell functions in a cellular model of Wolfram syndrome.

Wolfram syndrome is a rare multisystem disease characterized by childhood-onset diabetes mellitus and progressive neurodegeneration. Most cases are attributed to pathogenic variants in a single gene, Wolfram syndrome 1 (WFS1). There currently is no disease-modifying treatment for Wolfram syndrome, as the molecular consequences of the loss of WFS1 remain elusive. Because diabetes mellitus is the first diagnosed symptom of Wolfram syndrome, we aimed to further examine the functions of WFS1 in pancreatic ß cells in the context of hyperglycemia. Knockout (KO) of WFS1 in rat insulinoma (INS1) cells impaired calcium homeostasis and protein kinase B/Akt signaling and, subsequently, decreased cell viability and glucose-stimulated insulin secretion. Targeting calcium homeostasis with reexpression of WFS1, overexpression of WFS1's interacting partner neuronal calcium sensor-1 (NCS1), or treatment with calpain inhibitor and ibudilast reversed deficits observed in WFS1-KO cells. Collectively, our findings provide insight into the disease mechanism of Wolfram syndrome and highlight new targets and drug candidates to facilitate the development of a treatment for this disorder and similar diseases.

Why is Listeria monocytogenes such a potent inducer of CD8+ T-cells?

Listeria monocytogenes is a rapidly growing, Gram-positive, facultative intracellular pathogen that has been used for over 5 decades as a model to study basic aspects of infection and immunity. In a murine intravenous infection model, immunisation with a sublethal infection of L. monocytogenes initially leads to rapid intracellular multiplication followed by clearance of the bacteria and ultimately culminates in the development of long-lived cell-mediated immunity (CMI) mediated by antigen-specific CD8+ cytotoxic T-cells. Importantly, effective immunisation requires live, replicating bacteria. In this review, we summarise the cell and immunobiology of L. monocytogenes infection and discuss aspects of its pathogenesis that we suspect lead to robust CMI. We suggest five specific features of L. monocytogenes infection that positively impact the development of CMI: (a) the bacteria have a predilection for professional antigen-presenting cells; (b) the bacteria escape from phagosomes, grow, and secrete antigens into the host cell cytosol; (c) bacterial-secreted proteins enter the major histocompatibility complex (MHC) class I pathway of antigen processing and presentation; (d) the bacteria do not induce rapid host cell death; and (e) cytosolic bacteria induce a cytokine response that favours CMI. Collectively, these features make L. monocytogenes an attractive vaccine vector for both infectious disease applications and cancer immunotherapy.

Virulence factors enhance Citrobacter rodentium expansion through aerobic respiration.

Citrobacter rodentium uses a type III secretion system (T3SS) to induce colonic crypt hyperplasia in mice, thereby gaining an edge during its competition with the gut microbiota through an unknown mechanism. Here, we show that by triggering colonic crypt hyperplasia, the C. rodentium T3SS induced an excessive expansion of undifferentiated Ki67-positive epithelial cells, which increased oxygenation of the mucosal surface and drove an aerobic C. rodentium expansion in the colon. Treatment of mice with the γ-secretase inhibitor dibenzazepine to diminish Notch-driven colonic crypt hyperplasia curtailed the fitness advantage conferred by aerobic respiration during C. rodentium infection. We conclude that C. rodentium uses its T3SS to induce histopathological lesions that generate an intestinal microenvironment in which growth of the pathogen is fueled by aerobic respiration.

Energy Taxis toward Host-Derived Nitrate Supports a Salmonella Pathogenicity Island 1-Independent Mechanism of Invasion.

UNLABELLED: Salmonella enterica serovar Typhimurium can cross the epithelial barrier using either the invasion-associated type III secretion system (T3SS-1) or a T3SS-1-independent mechanism that remains poorly characterized. Here we show that flagellum-mediated motility supported a T3SS-1-independent pathway for entering ileal Peyer's patches in the mouse model. Flagellum-dependent invasion of Peyer's patches required energy taxis toward nitrate, which was mediated by the methyl-accepting chemotaxis protein (MCP) Tsr. Generation of nitrate in the intestinal lumen required inducible nitric oxide synthase (iNOS), which was synthesized constitutively in the mucosa of the terminal ileum but not in the jejunum, duodenum, or cecum. Tsr-mediated invasion of ileal Peyer's patches was abrogated in mice deficient for Nos2, the gene encoding iNOS. We conclude that Tsr-mediated energy taxis enables S Typhimurium to migrate toward the intestinal epithelium by sensing host-derived nitrate, thereby contributing to invasion of Peyer's patches. IMPORTANCE: Nontyphoidal Salmonella serovars, such as S. enterica serovar Typhimurium, are a common cause of gastroenteritis in immunocompetent individuals but can also cause bacteremia in immunocompromised individuals. While the invasion-associated type III secretion system (T3SS-1) is important for entry, S Typhimurium strains lacking a functional T3SS-1 can still cross the intestinal epithelium and cause a disseminated lethal infection in mice. Here we observed that flagellum-mediated motility and chemotaxis contributed to a T3SS-1-independent pathway for invasion and systemic dissemination to the spleen. This pathway required the methyl-accepting chemotaxis protein (MCP) Tsr and energy taxis toward host-derived nitrate, which we found to be generated by inducible nitric oxide synthase (iNOS) in the ileal mucosa prior to infection. Collectively, our data suggest that S Typhimurium enhances invasion by actively migrating toward the intestinal epithelium along a gradient of host-derived nitrate emanating from the mucosal surface of the ileum.

NOD1 and NOD2 signalling links ER stress with inflammation.

Endoplasmic reticulum (ER) stress is a major contributor to inflammatory diseases, such as Crohn disease and type 2 diabetes. ER stress induces the unfolded protein response, which involves activation of three transmembrane receptors, ATF6, PERK and IRE1α. Once activated, IRE1α recruits TRAF2 to the ER membrane to initiate inflammatory responses via the NF-κB pathway. Inflammation is commonly triggered when pattern recognition receptors (PRRs), such as Toll-like receptors or nucleotide-binding oligomerization domain (NOD)-like receptors, detect tissue damage or microbial infection. However, it is not clear which PRRs have a major role in inducing inflammation during ER stress. Here we show that NOD1 and NOD2, two members of the NOD-like receptor family of PRRs, are important mediators of ER-stress-induced inflammation in mouse and human cells. The ER stress inducers thapsigargin and dithiothreitol trigger production of the pro-inflammatory cytokine IL-6 in a NOD1/2-dependent fashion. Inflammation and IL-6 production triggered by infection with Brucella abortus, which induces ER stress by injecting the type IV secretion system effector protein VceC into host cells, is TRAF2, NOD1/2 and RIP2-dependent and can be reduced by treatment with the ER stress inhibitor tauroursodeoxycholate or an IRE1α kinase inhibitor. The association of NOD1 and NOD2 with pro-inflammatory responses induced by the IRE1α/TRAF2 signalling pathway provides a novel link between innate immunity and ER-stress-induced inflammation.

Alteraciones de la uretra en pediatría / Pediatric cystourethrography in congenital and acquired anomalies of the urethra

Nuestro propósito es ilustrar las variantes y alteraciones de la uretra en pediatría. Evaluamos y seleccionamos las imágenes más significativas de las distintas variantes anatómicas, malformaciones congénitas y lesiones adquiridas de la uretra de los estudios radiológicos (Cistouretrografía miccional y uretrografía retrógrada) realizados en nuestro servicio en los últimos 6 años (1995-2001). Las lesiones más frecuentes halladas fueron: hipospadia y válvulas de uretra posterior en el grupo de las malformaciones congénitas; ruptura de uretra por traumatismos dentro de las adquiridas y las estenosis secundarias a sondaje prolongado. La patología uretral en pediatría no es muy frecuente, para su adecuada interpretación debe conocerse la anatomía radiológica normal y sus variantes así como las asociaciones con otras alteraciones del desarrollo

Alteraciones de la uretra en pediatría / Pediatric cystourethrography in congenital and acquired anomalies of the urethra

Nuestro propósito es ilustrar las variantes y alteraciones de la uretra en pediatría. Evaluamos y seleccionamos las imágenes más significativas de las distintas variantes anatómicas, malformaciones congénitas y lesiones adquiridas de la uretra de los estudios radiológicos (Cistouretrografía miccional y uretrografía retrógrada) realizados en nuestro servicio en los últimos 6 años (1995-2001). Las lesiones más frecuentes halladas fueron: hipospadia y válvulas de uretra posterior en el grupo de las malformaciones congénitas; ruptura de uretra por traumatismos dentro de las adquiridas y las estenosis secundarias a sondaje prolongado. La patología uretral en pediatría no es muy frecuente, para su adecuada interpretación debe conocerse la anatomía radiológica normal y sus variantes así como las asociaciones con otras alteraciones del desarrollo (AU)

Valor de la ultrasonografía en el diagnóstico de quiste de colédoco / Choledochal cyst: sonographic diagnostic value in a pediatric series

Con el objeto de demostrar la utilidad de la US en el diagnóstico de quiste de colédoco en pediatría, se analizaron retrospectivamente 37 historias clínicas de pacientes con diagnóstico histopatológico de dicha patología. Los hallazgos obtenidos mostraron que los síntomas clínicos más frecuentes fueron ictericia, dolor, acolia y vómitos. La US tuvo una sensibilidad de 97,2 por ciento. La colangiografía intraoperatoria confirmó el diagnóstico ultrasonográfico, permitió la clasificación anatómica y descubrió anomalías de la unión pancreatobiliar. Otras modalidades de diagnóstico por imágenes, de mayor complejidad, no aportaron datos relevantes tanto para el diagnóstico como para la conducta terapéutica. La US es el método de elección para realizar el diagnóstico, no es invasiva y es de bajo costo

Valor de la ultrasonografía en el diagnóstico de quiste de colédoco / Choledochal cyst: sonographic diagnostic value in a pediatric series

Con el objeto de demostrar la utilidad de la US en el diagnóstico de quiste de colédoco en pediatría, se analizaron retrospectivamente 37 historias clínicas de pacientes con diagnóstico histopatológico de dicha patología. Los hallazgos obtenidos mostraron que los síntomas clínicos más frecuentes fueron ictericia, dolor, acolia y vómitos. La US tuvo una sensibilidad de 97,2 por ciento. La colangiografía intraoperatoria confirmó el diagnóstico ultrasonográfico, permitió la clasificación anatómica y descubrió anomalías de la unión pancreatobiliar. Otras modalidades de diagnóstico por imágenes, de mayor complejidad, no aportaron datos relevantes tanto para el diagnóstico como para la conducta terapéutica. La US es el método de elección para realizar el diagnóstico, no es invasiva y es de bajo costo (AU)

Bilateral mucous cell containing dentigerous cyst of madibular third molars: report of an unusual case

A 38-year-old Caucasian male with bilateral dentigerous cysts of the mandibular third molars is reported as follows. The cyst cavities were lined with a nonkeratinized squamous epithelium. Mucous cells were seen in some areas of the cyst walls

Eficacia del ácido tiaprofénico en lesiones traumáticas agudas / Efficiency of thiaprophenic acid in traumatic lesions

Se realizó un estudio abierto no comparativo para valorar eficacia y tolerancia del ácido tiaprofénico en el tratamiento de lesiones traumáticas agudas, producidas durante la actividad deportiva. Se estudiaron 50 pacientes masculinos cocn lesiones traumáticas diversas. Los parámetros valorados fueron: dolor, aumento de volumen y limitación funcional antes y después del tratamiento, obteniéndose mejoría significativa (p < 0.005) después de cinco días de tratamiento. La instalación del efecto antálgico en 92% de los casos fue dentro de los primeros 30 minutos y la duración del efecto fue de ocho a 12 horas en 82%. La valoración global muestra resultados excelentes y buenos en 88 y 92% según pacientes e investigador. El ácido tiaprofénico fue bien tolerado. Se concluye que el ácido tiaprofénico por su rápido efecto antinflamatorio y natálgico como por su buena tolerancia, es un medicamento eficaz en el tratamiento de las lesiones traumapticas agudas