Prophylactic treatment with the c-Abl inhibitor, neurotinib, diminishes neuronal damage and the convulsive state in pilocarpine-induced mice.

The molecular mechanisms underlying seizure generation remain elusive, yet they are crucial for developing effective treatments for epilepsy. The current study shows that inhibiting c-Abl tyrosine kinase prevents apoptosis, reduces dendritic spine loss, and maintains N-methyl-d-aspartate (NMDA) receptor subunit 2B (NR2B) phosphorylated in in vitro models of excitotoxicity. Pilocarpine-induced status epilepticus (SE) in mice promotes c-Abl phosphorylation, and disrupting c-Abl activity leads to fewer seizures, increases latency toward SE, and improved animal survival. Currently, clinically used c-Abl inhibitors are non-selective and have poor brain penetration. The allosteric c-Abl inhibitor, neurotinib, used here has favorable potency, selectivity, pharmacokinetics, and vastly improved brain penetration. Neurotinib-administered mice have fewer seizures and improved survival following pilocarpine-SE induction. Our findings reveal c-Abl kinase activation as a key factor in ictogenesis and highlight the impact of its inhibition in preventing the insurgence of epileptic-like seizures in rodents and humans.

Education's impact on primary care dentists' confidence in treating patients with special health care needs.

INTRODUCTION: Special care dentistry (SCD) is still developing in XX. This study aimed to clarify whether primary care dentists are treating patients with special health care needs (SHCN), to know if they have had previous education on SCD (on an undergraduate or postgraduate level), whether their training level impacts their confidence when treating patients with SHCN, and to assess their opinion on SCD as a relevant topic in undergraduate education. METHODS: A survey was answered by 149 primary care dentists working for the National Health Service of the XX region in XX, including information on their daily clinical practice, undergraduate, and postgraduate training in SCD, and their opinions on them. RESULTS: Most interviewees would like to complement their training and believed that SCD should be formally incorporated into undergraduate programs. There was a significant association between confidence in treating patients with SHCN and the rating of their undergraduate training, and between confidence and the number of hours of continuous development courses. CONCLUSION: Most primary care dentists treat patients with SHCN regularly. Therefore, including training in the undergraduate curriculum and afterward becomes necessary to increase their confidence when facing this challenging group of patients.

c-Abl tyrosine kinase down-regulation as target for memory improvement in Alzheimer's disease.

Background: Growing evidence suggests that the non-receptor tyrosine kinase, c-Abl, plays a significant role in the pathogenesis of Alzheimer's disease (AD). Here, we analyzed the effect of c-Abl on the cognitive performance decline of APPSwe/PSEN1ΔE9 (APP/PS1) mouse model for AD. Methods: We used the conditional genetic ablation of c-Abl in the brain (c-Abl-KO) and pharmacological treatment with neurotinib, a novel allosteric c-Abl inhibitor with high brain penetrance, imbued in rodent's chow. Results: We found that APP/PS1/c-Abl-KO mice and APP/PS1 neurotinib-fed mice had improved performance in hippocampus-dependent tasks. In the object location and Barnes-maze tests, they recognized the displaced object and learned the location of the escape hole faster than APP/PS1 mice. Also, APP/PS1 neurotinib-fed mice required fewer trials to reach the learning criterion in the memory flexibility test. Accordingly, c-Abl absence and inhibition caused fewer amyloid plaques, reduced astrogliosis, and preserved neurons in the hippocampus. Discussion: Our results further validate c-Abl as a target for AD, and the neurotinib, a novel c-Abl inhibitor, as a suitable preclinical candidate for AD therapies.

Política pública en cuidados paliativos y sus implicaciones sobre servicios, opioides y educación en Colombia / Public policy on palliative care and its implications for services, opioids, and education in Colombia

Introducción: El desarrollo de cuidados paliativos exige la intervención de múltiples dimensiones de salud pública, incluyendo la disponibilidad de servicios de salud, medicamentos esenciales y programas educativos. En Colombia se han realizado diversos cambios en las políticas públicas para promover la atención de personas con necesidades paliativas. Objetivo: Evaluar empíricamente las políticas públicas, existentes en cuidados paliativos y sus implicaciones sobre disponibilidad de servicios, opioides y programas educativos en los años 2010 ­ 2019 en Colombia. Materiales y métodos: Se diseñó un estudio mixto exploratorio secuencial en tres fases: identificación de indicadores empíricos de políticas nacionales, diagnostico situacional de cuidados paliativos y evaluación cualitativa de los resultados de la implementación de políticas en siete nodos territoriales de Colombia. Resultados: Se revisaron siete normas obteniendo 12 indicadores empíricos para la evaluación, seis de ellos no contaban con fuentes de información. El diagnostico nacional evidencia un aumento gradual de servicios y consumo de opioides en los años hito del desarrollo de políticas. 44 profesionales de cuidados paliativos perciben un efecto positivo de las políticas públicas en el consumo de opioides y bajos resultados para el dominio de servicios y educación Conclusiones: Existe una relación positiva entre políticas públicas y consumo de opioides, una relación cuantitativa positiva para servicios de cuidados paliativos y una relación cuanticualitativa negativa para programas educativos, lo que denota un bajo estatus operativo de las políticas construidas para mejorar el dolor y sufrimiento asociado a la enfermedad crónica avanzada.

Introduction: Palliative care development requires the intervention of multiple dimensions of public health, including the availability of health services, essential medicines, and educational programs. In Colombia, several changes have been made in public policy to promote the care of people with palliative needs. Objective: To empirically evaluate existing public policies on palliative care and their implications for the availability of services, opioids, and educational programs during the years 2010 to 2019 in Colombia. Materials and methods: A mixed sequential exploratory study was designed in three phases: identification of empirical indicators of national policies, palliative care situational diagnosis, and qualitative assessment of the results of policy implementation in seven regional nodes in Colombia. Results: Seven standards were reviewed, yielding 12 empirical indicators for assessment, six of which had no sources of information. The national diagnosis shows a gradual increase in services and opioid use during the landmark years of policy development. Forty-four palliative care professionals perceive a positive effect of public policy on opioid use and low outcomes for service and education domains. Conclusions: There is a positive relationship between public policy and opioid use, a positive quantitative relationship with palliative care services, and a negative quantitative-qualitative relationship with educational programs. This indicates a low operational status of policies designed to alleviate the pain and suffering associated with advanced chronic diseases.

Introdução: O desenvolvimento dos cuidados paliativos requer a intervenção de múltiplas dimensões da saúde pública, incluindo a disponibilidade de serviços de saúde, medicamentos essenciais e programas educativos. Na Colômbia, várias mudanças foram feitas nas políticas públicas para promover o cuidado de pessoas com necessidades paliativas. Objetivo: Avaliar empiricamente as políticas públicas existentes em cuidados paliativos e suas implicações na disponibilidade de serviços, opioides e programas educacionais nos anos 2010 - 2019 na Colômbia. Materiais e métodos: Desenhou-se um estudo misto exploratório sequencial em três fases: identificação de indicadores empíricos de políticas nacionais, diagnóstico situacional de cuidados paliativos e avaliação qualitativa dos resultados da implementação de políticas em sete nodos territoriais da Colômbia. Resultados: Sete normas foram revisadas, obtendo-se 12 indicadores empíricos para avaliação, seis delas não possuíam fontes de informação. O diagnóstico nacional mostra um aumento gradual nos serviços e consumo de opioides nos anos marcantes do desenvolvimento de políticas. 44 profissionais de cuidados paliativos percebem efeito positivo das políticas públicas sobre o consumo de opioides e resultados baixos para o domínio serviços e educação Conclusões: Existe relação positiva entre políticas públicas e consumo de opioides, relação quantitativa positiva para serviços de cuidados paliativos e negativa relação quantitativo-qualitativa para programas educativos, o que denota um baixo status operacional das políticas destinadas a melhorar a dor e o sofrimento associados à doença crônica avançada.

Comparison of Two Tuberculosis Infection Tests in a South American Tertiary Hospital: STANDARD F TB-Feron FIA vs. QIAreachTM QuantiFERON-TB.

INTRODUCTION: Tuberculosis (TB) is one of the most prevalent respiratory diseases in the world. In 2020 there were at least 9.9 million new infections, with 1.5 million deaths. Approximately 10% of people infected with Mycobacterium tuberculosis develop the disease during the first 2 to 5 years after infection. In South America, the diagnosis of Latent Tuberculosis Infections (LTBI) continues to be performed through the Mantoux tuberculin skin test (TST). OBJECTIVE: The objective of our study was to compare the sensitivity of a new immunofluorescence IGRA test against a widely available IGRA kit on the market. MATERIAL AND METHOD: Close contact with infectious TB patients, HIV patients, or immunocompromised for another cause were recruited. Two interferon-gamma release assay (IGRA) diagnostic kits were used and compared with TST. RESULTS: 76 patients were recruited, 93.42% were Chilean nationality, and 98.68% of the patients did not have immunosuppression. The sensitivity of the new technique was 88.89%, and the specificity was 92.50% in the study population compared to the IGRA previously used. In the subgroup older than 36 years, the sensitivity was 95.65%, and the specificity was 89.47%. CONCLUSION: IGRA techniques are a new resource in clinical laboratories to make an accurate diagnosis of LTBI in the region of the Americas. In our population, the greatest benefit of this new IGRA would be observed in people over 36 years of age, where the sensitivity of the technique was like that of the currently available test.

c-Abl kinase at the crossroads of healthy synaptic remodeling and synaptic dysfunction in neurodegenerative diseases.

Our ability to learn and remember depends on the active formation, remodeling, and elimination of synapses. Thus, the development and growth of synapses as well as their weakening and elimination are essential for neuronal rewiring. The structural reorganization of synaptic complexes, changes in actin cytoskeleton and organelle dynamics, as well as modulation of gene expression, determine synaptic plasticity. It has been proposed that dysregulation of these key synaptic homeostatic processes underlies the synaptic dysfunction observed in many neurodegenerative diseases. Much is known about downstream signaling of activated N-methyl-D-aspartate and α-amino-3-hydroxy-5-methyl-4-isoazolepropionate receptors; however, other signaling pathways can also contribute to synaptic plasticity and long-lasting changes in learning and memory. The non-receptor tyrosine kinase c-Abl (ABL1) is a key signal transducer of intra and extracellular signals, and it shuttles between the cytoplasm and the nucleus. This review focuses on c-Abl and its synaptic and neuronal functions. Here, we discuss the evidence showing that the activation of c-Abl can be detrimental to neurons, promoting the development of neurodegenerative diseases. Nevertheless, c-Abl activity seems to be in a pivotal balance between healthy synaptic plasticity, regulating dendritic spines remodeling and gene expression after cognitive training, and synaptic dysfunction and loss in neurodegenerative diseases. Thus, c-Abl genetic ablation not only improves learning and memory and modulates the brain genetic program of trained mice, but its absence provides dendritic spines resiliency against damage. Therefore, the present review has been designed to elucidate the common links between c-Abl regulation of structural changes that involve the actin cytoskeleton and organelles dynamics, and the transcriptional program activated during synaptic plasticity. By summarizing the recent discoveries on c-Abl functions, we aim to provide an overview of how its inhibition could be a potentially fruitful treatment to improve degenerative outcomes and delay memory loss.

Identification of Exoenzymes Secreted by Entomopathogenic Fungus Beauveria pseudobassiana RGM 2184 and Their Effect on the Degradation of Cocoons and Pupae of Quarantine Pest Lobesia botrana.

Beauveria pseudobassiana RGM 2184 has shown 80% maximum efficacy against the pest Lobesia botrana in the autumn and winter seasons. This suggests that the strain possesses an interesting battery of enzymes that are cold-adapted to penetrate the thick and hydrophobic cocoon of L. botrana. In this study, screening of the proteolytic, lipolytic, and chitinolytic activity of enzyme extracts secreted by the RGM 2184 strain was carried out in various culture media. The enzyme extracts with the highest activity were subjected to zymography and mass spectrometry. These analyses allowed the identification of two proteases, two lipases, and three chitinases. Comparative analysis indicated that the degree of similarity between these enzymes was substantially reduced when the highest degree of taxonomic relatedness between RGM 2184 and the entomopathogenic fungus strain was at the family level. These results suggest that there is a wide variety of exoenzymes in entomopathogenic fungi species belonging to the order Hypocreales. On the other hand, exoenzyme extract exposure of cocoons and pupae of L. botrana provoked damage at 10 °C. Additionally, an analysis of the amino acid composition of the RGM 2184 exoenzyme grouped them close to the cold-adapted protein cluster. These results support the use of this strain to control pests in autumn and winter. Additionally, these antecedents can form a scaffold for the future characterization of these exoenzymes along with the optimization of the strain's biocontrol ability by overexpressing them.

c-Abl regulates a synaptic plasticity-related transcriptional program involved in memory and learning.

Memory consolidation requires activation of a gene expression program that allows de novo protein synthesis. But the molecular mechanisms that favour or restrict that program are poorly understood. The kinase c-Abl can modulate gene expression through transcription factors and chromatin modifiers. Here, we show that c-Abl ablation in the brain improves learning acquisition and memory consolidation in mice. Its absence also affects gene expression profiles in the mouse hippocampus. We found that genes involved in synaptic plasticity and actin cytoskeleton dynamics, such as Arp2 and Thorase, are up-regulated at the mRNA and protein levels in trained c-Abl KO mice and by a chemical-LTP stimulus. Trained c-Abl KO mice also show that dendritic spines are larger than in wild-type mice and present at a higher density. These results indicate that c-Abl kinase is an important part of the mechanism that limits or restricts signalling of relevant gene programs involved in morphological and functional spine changes upon neuronal stimulation.

Evaluation of the Antiviral Activity against Infectious Pancreatic Necrosis Virus (IPNV) of a Copper (I) Homoleptic Complex with a Coumarin as Ligand.

The aquatic infectious pancreatic necrosis virus (IPNV) causes a severe disease in farmed salmonid fish that generates great economic losses in the aquaculture industry. In the search for new tools to control the disease, in this paper we show the results obtained from the evaluation of the antiviral effect of [Cu(NN1)2](ClO4) Cu(I) complex, synthesized in our laboratory, where the NN1 ligand is a synthetic derivate of the natural compound coumarin. This complex demonstrated antiviral activity against IPNV at 5.0 and 15.0 µg/mL causing a decrease viral load 99.0% and 99.5%, respectively. The Molecular Docking studies carried out showed that the copper complex would interact with the VP2 protein, specifically in the S domain, altering the process of entry of the virus into the host cell.

Modulation of Escherichia coli Translation by the Specific Inactivation of tRNAGly Under Oxidative Stress.

Bacterial oxidative stress responses are generally controlled by transcription factors that modulate the synthesis of RNAs with the aid of some sRNAs that control the stability, and in some cases the translation, of specific mRNAs. Here, we report that oxidative stress additionally leads to inactivation of tRNAGly in Escherichia coli, inducing a series of physiological changes. The observed inactivation of tRNAGly correlated with altered efficiency of translation of Gly codons, suggesting a possible mechanism of translational control of gene expression under oxidative stress. Changes in translation also depended on the availability of glycine, revealing a mechanism whereby bacteria modulate the response to oxidative stress according to the prevailing metabolic state of the cells.

Genotoxic stress triggers the activation of IRE1α-dependent RNA decay to modulate the DNA damage response.

The molecular connections between homeostatic systems that maintain both genome integrity and proteostasis are poorly understood. Here we identify the selective activation of the unfolded protein response transducer IRE1α under genotoxic stress to modulate repair programs and sustain cell survival. DNA damage engages IRE1α signaling in the absence of an endoplasmic reticulum (ER) stress signature, leading to the exclusive activation of regulated IRE1α-dependent decay (RIDD) without activating its canonical output mediated by the transcription factor XBP1. IRE1α endoribonuclease activity controls the stability of mRNAs involved in the DNA damage response, impacting DNA repair, cell cycle arrest and apoptosis. The activation of the c-Abl kinase by DNA damage triggers the oligomerization of IRE1α to catalyze RIDD. The protective role of IRE1α under genotoxic stress is conserved in fly and mouse. Altogether, our results uncover an important intersection between the molecular pathways that sustain genome stability and proteostasis.

c-Abl Deficiency Provides Synaptic Resiliency Against Aß-Oligomers.

Spine pathology has been implicated in the early onset of Alzheimer's disease (AD), where Aß-Oligomers (AßOs) cause synaptic dysfunction and loss. Previously, we described that pharmacological inhibition of c-Abl prevents AßOs-induced synaptic alterations. Hence, this kinase seems to be a key element in AD progression. Here, we studied the role of c-Abl on dendritic spine morphological changes induced by AßOs using c-Abl null neurons (c-Abl-KO). First, we characterized the effect of c-Abl deficiency on dendritic spine density and found that its absence increases dendritic spine density. While AßOs-treatment reduces the spine number in both wild-type (WT) and c-Abl-KO neurons, AßOs-driven spine density loss was not affected by c-Abl. We then characterized AßOs-induced morphological changes in dendritic spines of c-Abl-KO neurons. AßOs induced a decrease in the number of mushroom spines in c-Abl-KO neurons while preserving the populations of immature stubby, thin, and filopodia spines. Furthermore, synaptic contacts evaluated by PSD95/Piccolo clustering and cell viability were preserved in AßOs-exposed c-Abl-KO neurons. In conclusion, our results indicate that in the presence of AßOs c-Abl participates in synaptic contact removal, increasing susceptibility to AßOs damage. Its deficiency increases the immature spine population reducing AßOs-induced synapse elimination. Therefore, c-Abl signaling could be a relevant actor in the early stages of AD.

Autoexamen de seno: conocimientos, actitudes y prácticas en mujeres de una institución de educación superior / Self-examination of breast: Knowledge, attitudes and practices in women of a higher education institution / Autoexame das mamas: conhecimentos, atitudes e práticas em mulheres de uma instituição de ensino superior

Introducción. Según la Organización Mundial de la Salud, el cáncer de seno es el segundo más común en el mundo, con un estimado de 1,67 millones de casos nuevos diagnosticados en 2012, lo que equivale al 25 % de todos los cánceres.Objetivo. Identificar los conocimientos, actitudes y prácticas frente al autoexamen de seno en mujeres de una institución de educación superior, durante el segundo semestre de 2017. Materiales y métodos. Se llevó a cabo un estudio de enfoque cuantitativo, de tipo descriptivo y transversal en una población 1125 estudiantes de sexo femenino. Su duración fue de un año y se contó con una muestra de 287 participantes de una institución de educación superior. La información se recolectó mediante una encuesta para evaluar los conocimientos, actitudes y prácticas del autoexa-men de seno. Resultados. El 40,7 % de la población estudiada sí se practica el autoexamen de seno, 72,03 % con una frecuencia adecuada y 38,13 % en la etapa sugerida del ciclo menstrual. Conclusión. La mayor parte de la población no se practica el autoexamen, además, existe poca clari-dad sobre la frecuencia y el momento en que se debe hacer

Introduction. According to World Health Organization, breast cancer is the second most common cancer in the world with an estimated 1.67 million new cases of cancer diagnosed in 2012, equivalent to 25% of all cancers. Objective. Identify the knowledge, attitudes and practices facing breast self-examination in women of a higher education institution during the second semester of 2017Materials and methods. Quantitative, descriptive and transversal was carried out in a population 1,125 students of female gender; the study elapsed one year, on a sample of 287 participants of a higher education institution. Information collection was conducted using a survey to evaluate knowle-dge, attitudes and practices of breast self-examination.Results. 40.7% of the studied population does practice breast self-examination, being 72.03% with an adequate frequency and 38.13% in the suggested stage of the menstrual cycle.Conclusion. The major part of the population does not practice self-examination, and there is poor clarity about frequency and time in which it should be performed

Introdução. Segundo a Organização Mundial da Saúde, o câncer de mama é o segundo de neoplasia mais frequente no mundo, com um número estimado de 1,67 milhões de novos casos diagnosticados em 2012, o equivalente a 25% de todos os tipos de câncer.Objetivo. Identificar conhecimentos, atitudes e práticas sobre o auto-exame das mamas em mulheres de uma instituição de ensino superior, durante o segundo semestre de 2017.Materiais e métodos. Foi realizado um estudo de abordagem quantitativa, descritiva e transversal em uma população de 1125 estudantes do sexo feminino. Sua duração foi de um ano e uma amostra de 287 participantes de uma instituição de ensino superior. As informações foram coletadas por meio de uma pesquisa para avaliar os conhecimentos, atitudes e práticas do auto-exame das mamas.Resultados. 40,7% da população estudada realiza auto-exame das mamas, 72,03% com frequência adequada e 38,13% na fase sugerida do ciclo menstrual.Conclusão. A maior parte da população não pratica o auto-exame; além disso, há pouca clareza sobre a frequência e o momento em que deve ser feito

Tratamientos alternativos de medicina tradicional para Chlamydia trachomatis, agente causal de una infección asintomática / Alternative Treatments of Traditional Medicine for Chlamydia trachomatis, Causal Agent of an Asympomatic Infection

Resumen En la actualidad, Chlamydia trachomatis (CT) es una de las causas más frecuentes de infecciones de transmisión sexual (ITS) y morbilidad reproductiva en el mundo, Incluye tanto países desarrollados como en vía de desarrollo, con un reporte alrededor de 92 millones de casos anuales. CT es una bacteria intracelular obligada cuyo inicio de la infección es asintomático, causa infección crónica, puede generar infección persistente y complicaciones como cáncer de ovario. Las infecciones por CT son asintomáticas en el 70% de las mujeres y el 40% de los hombres, lo que dificulta el diagnóstico en las fases tempranas de la infección y el tratamiento oportuno, lo que conlleva a un aumento en los contagios en la población. De acuerdo con la Organización Mundial de la Salud (OMS), el tratamiento para CT incluye la utilización de antibióticos tipo tetraciclinas, macrólidos y fluoroquinolonas. Sin embargo, a pesar de su alta tasa de eficacia, cada vez son más recurrentes las infecciones. Reportes recientes han demostrado resistencia por parte de los cuerpos elementales y se ha podido determinar que los antibióticos disminuyen la población de lactobacillus vaginales beneficiosos, causando mayores complicaciones en los pacientes. Basados en estos hallazgos, las investigaciones actuales se han centrado en terapias alternativas que reduzcan la actividad antichlamydial y que sean de libre acceso, generando el menor daño posible en los pacientes.

Abstract Currently, Chlamydia trachomatis (CT) is one of the most frequent causes of sexually transmitted infections (STIs) and reproductive morbidity in the world, including both developed and developing countries, with a report of around 92 million annual cases. CT is an obligate intracellular bacterium whose onset's infection is asymptomatic, causes chronic infection, can generate persistent infection and complications such as ovarian cancer. CT infections are asymptomatic in 70% of women and 40% of men, which makes diagnosis difficult in the early stages of infection and timely treatment, which leads to an increase in infections in the population. According to the World Health Organization (WHO), treatment for TC includes the use of antibiotics such as tetracyclines, macrolides and fluoroquinolones. However, despite their high efficacy rate, infections are becoming more frequent. Recent reports have shown resistance on the part of elementary bodies and it has been determined that antibiotics decrease the beneficial vaginal lactobacillus population, causing greater complications in patients. Based on these findings, current research has focused on alternative therapies that reduce antichlamydial activity and that are freely accessible, generating the least possible harm to patients.

Coli Surface Antigen 26 Acts as an Adherence Determinant of Enterotoxigenic Escherichia coli and Is Cross-Recognized by Anti-CS20 Antibodies.

The coli surface antigen 26 (CS26) of enterotoxigenic Escherichia coli (ETEC) had been described as a putative adhesive pilus based on the partial sequence of the crsH gene, detected in isolates from children with diarrhea in Egypt. However, its production and activity as adherence determinant has not been experimentally addressed. The crsH was identified as a homolog of genes encoding structural subunits of ETEC colonization factors (CFs) CS12, CS18, and CS20. These CFs, along with the recently discovered CS30, belong to the γ2 family of pili assembled by the chaperone-usher pathway (CU pili). Further, the complete CS26 locus, crsHBCDEFG, was described in an O141 ETEC strain (ETEC 100664) obtained from a diarrhea case in The Gambia, during the Global Enterics Multicenter Study. Here, we report that CS26 is a pilus of ∼10 nm in diameter, with the capacity to increase the cell adherence of the non-pathogenic strain E. coli DH10B. As for other related pili, production of CS26 seems to be regulated by phase variation. Deletion of crsHBCDEFG in ETEC 100664 significantly decreased its adherence capacity, which was recovered by in trans complementation. Furthermore, CrsH was cross-recognized by polyclonal antibodies directed against the major structural subunit of CS20, CsnA, as determined by Western blotting and immunogold labeling. ETEC CS26+ strains were found to harbor the heat-labile enterotoxin only, within three different sequence types of phylogroups A and B1, the latter suggesting acquisition through independent events of horizontal transfer. Overall, our results demonstrate that CS26 is an adhesive pilus of human ETEC. In addition, cross-reactivity with anti-CsnA antibodies indicate presence of common epitopes in γ2-CFs.

Mechanosensory organ regeneration in zebrafish depends on a population of multipotent progenitor cells kept latent by Schwann cells.

BACKGROUND: Regenerating damaged tissue is a complex process, requiring progenitor cells that must be stimulated to undergo proliferation, differentiation and, often, migratory behaviors and morphological changes. Multiple cell types, both resident within the damaged tissue and recruited to the lesion site, have been shown to participate. However, the cellular and molecular mechanisms involved in the activation of progenitor cell proliferation and differentiation after injury, and their regulation by different cells types, are not fully understood. The zebrafish lateral line is a suitable system to study regeneration because most of its components are fully restored after damage. The posterior lateral line (PLL) is a mechanosensory system that develops embryonically and is initially composed of seven to eight neuromasts distributed along the trunk and tail, connected by a continuous stripe of interneuromastic cells (INCs). The INCs remain in a quiescent state owing to the presence of underlying Schwann cells. They become activated during development to form intercalary neuromasts. However, no studies have described if INCs can participate in a regenerative event, for example, after the total loss of a neuromast. RESULTS: We used electroablation in transgenic larvae expressing fluorescent proteins in PLL components to completely ablate single neuromasts in larvae and adult fish. This injury results in discontinuity of the INCs, Schwann cells, and the PLL nerve. In vivo imaging showed that the INCs fill the gap left after the injury and can regenerate a new neuromast in the injury zone. Further, a single INC is able to divide and form all cell types in a regenerated neuromast and, during this process, it transiently expresses the sox2 gene, a neural progenitor cell marker. We demonstrate a critical role for Schwann cells as negative regulators of INC proliferation and neuromast regeneration, and that this inhibitory property is completely dependent on active ErbB signaling. CONCLUSIONS: The potential to regenerate a neuromast after damage requires that progenitor cells (INCs) be temporarily released from an inhibitory signal produced by nearby Schwann cells. This simple yet highly effective two-component niche offers the animal robust mechanisms for organ growth and regeneration, which can be sustained throughout life.

Chaperone-Usher Pili Loci of Colonization Factor-Negative Human Enterotoxigenic Escherichia coli.

Enterotoxigenic Escherichia coli (ETEC) is one of the most common causes of diarrhea worldwide. Among the 25 different ETEC adhesins, 22 are known as "colonization factors" (CFs), of which 17 are assembled by the chaperone-usher (CU) mechanism. Currently, there is no preventive therapy against ETEC, and CFs have been proposed as components for vaccine development. However, studies of diarrhea-causing ETEC strains worldwide indicate that between 15 and 50% of these are negative for known CFs, hindering the selection of the most widespread structures and suggesting that unknown adhesins remain to be identified. Here, we report the result of a comprehensive analysis of 35 draft genomes of ETEC strains which do not carry known adhesin genes; our goal was to find new CU pili loci. The phylogenetic profiles and serogroups of these strains were highly diverse, a majority of which produced only the heat-labile toxin. We identified 10 pili loci belonging to CU families ß (1 locus), γ2 (7 loci), κ (1 locus), and π (1 locus), all of which contained the required number of open reading frames (ORFs) to encode functional structures. Three loci were variants of previously-known clusters, three had been only-partially described, and four are novel loci. Intra-loci genetic variability identified would allow the synthesis of up to 14 different structures. Clusters of putative γ2-CU pili were most common (23 strains), followed by putative ß-CU pili (12 strains), which have not yet been fully characterized. Overall, our findings significantly increase the number of ETEC adhesion genes associated with human infections.

TleA, a Tsh-like autotransporter identified in a human enterotoxigenic Escherichia coli strain.

Enterotoxigenic Escherichia coli (ETEC), a leading cause of acute diarrhea, colonizes the intestine by means of adhesins. However, 15 to 50% of clinical isolates are negative for known adhesins, making it difficult to identify antigens for broad-coverage vaccines. The ETEC strain 1766a, obtained from a child with watery diarrhea in Chile, harbors the colonization factor CS23 but is negative for other known adhesins. One clone, derived from an ETEC 1766a genomic library (clone G10), did not produce CS23 yet was capable of adhering to Caco-2 cells. The goal of this study was to identify the gene responsible for this capacity. Random transposon-based mutagenesis allowed the identification of a 4,110-bp gene that codes for a homologue of the temperature-sensitive hemagglutinin (Tsh) autotransporter described in avian E. coli strains (97% identity, 90% coverage) and that is called TleA (Tsh-like ETEC autotransporter) herein. An isogenic ETEC 1766a strain with a tleA mutation showed an adhesion level similar to that of the wild-type strain, suggesting that the gene does not direct attachment to Caco-2 cells. However, expression of tleA conferred the capacity for adherence to nonadherent E. coli HB101. This effect coincided with the detection of TleA on the surface of nonpermeabilized bacteria, while, conversely, ETEC 1766a seems to secrete most of the produced autotransporter to the medium. On the other hand, TleA was capable of degrading bovine submaxillary mucin and leukocyte surface glycoproteins CD45 and P-selectin glycoprotein ligand 1 (PSGL-1). These results suggest that TleA promotes colonization of the intestinal epithelium and that it may modulate the host immune response.

Immunoproteomic analysis to identify Shiga toxin-producing Escherichia coli outer membrane proteins expressed during human infection.

Shiga-toxin producing Escherichia coli (STEC) is the etiologic agent of acute diarrhea, dysentery, and hemolytic-uremic syndrome (HUS). There is no approved vaccine for STEC infection in humans, and antibiotic use is contraindicated, as it promotes Shiga toxin production. In order to identify STEC-associated antigens and immunogenic proteins, outer membrane proteins (OMPs) were extracted from STEC O26:H11, O103, O113:H21, and O157:H7 strains, and commensal E. coli strain HS was used as a control. SDS-PAGE, two-dimensional-PAGE analysis, Western blot assays using sera from pediatric HUS patients and controls, and matrix-assisted laser desorption ionization-tandem time of flight analyses were used to identify 12 immunogenic OMPs, some of which were not reactive with control sera. Importantly, seven of these proteins have not been previously reported to be immunogenic in STEC strains. Among these seven proteins, OmpT and Cah displayed IgG and IgA reactivity with sera from HUS patients. Genes encoding these two proteins were present in a majority of STEC strains. Knowledge of the antigens produced during infection of the host and the immune response to those antigens will be important for future vaccine development.