Pore-forming activity of S. pneumoniae pneumolysin disrupts the paracellular localization of the epithelial adherens junction protein E-cadherin.

Streptococcus pneumoniae, a common cause of community-acquired bacterial pneumonia, can cross the respiratory epithelial barrier to cause lethal septicemia and meningitis. S. pneumoniae pore-forming toxin pneumolysin (PLY) triggers robust neutrophil (PMN) infiltration that promotes bacterial transepithelial migration in vitro and disseminated disease in mice. Apical infection of polarized respiratory epithelial monolayers by S. pneumoniae at a multiplicity of infection (MOI) of 20 resulted in recruitment of PMNs, loss of 50% of the monolayer, and PMN-dependent bacterial translocation. Reducing the MOI to 2 decreased PMN recruitment two-fold and preserved the monolayer, but apical-to-basolateral translocation of S. pneumoniae remained relatively efficient. At both MOI of 2 and 20, PLY was required for maximal PMN recruitment and bacterial translocation. Co-infection by wild-type S. pneumoniae restored translocation by a PLY-deficient mutant, indicating that PLY can act in trans. Investigating the contribution of S. pneumoniae infection on apical junction complexes in the absence of PMN transmigration, we found that S. pneumoniae infection triggered the cleavage and mislocalization of the adherens junction (AJ) protein E-cadherin. This disruption was PLY-dependent at MOI of 2 and was recapitulated by purified PLY, requiring its pore-forming activity. In contrast, at MOI of 20, E-cadherin disruption was independent of PLY, indicating that S. pneumoniae encodes multiple means to disrupt epithelial integrity. This disruption was insufficient to promote bacterial translocation in the absence of PMNs. Thus, S. pneumoniae triggers cleavage and mislocalization of E-cadherin through PLY-dependent and -independent mechanisms, but maximal bacterial translocation across epithelial monolayers requires PLY-dependent neutrophil transmigration.

Dynamic Python-Based Method Provides Quantitative Analysis of Intercellular Junction Organization During S. pneumoniae Infection of the Respiratory Epithelium.

Many respiratory pathogens compromise epithelial barrier function during lung infection by disrupting intercellular junctions, such as adherens junctions and tight junctions, that maintain intercellular integrity. This includes Streptococcus pneumoniae, a leading cause of pneumonia, which can successfully breach the epithelial barrier and cause severe infections such as septicemia and meningitis. Fluorescence microscopy analysis on intercellular junction protein manipulation by respiratory pathogens has yielded major advances in our understanding of their pathogenesis. Unfortunately, a lack of automated image analysis tools that can tolerate variability in sample-sample staining has limited the accuracy in evaluating intercellular junction organization quantitatively. We have created an open source, automated Python computer script called "Intercellular Junction Organization Quantification" or IJOQ that can handle a high degree of sample-sample staining variability and robustly measure intercellular junction integrity. In silico validation of IJOQ was successful in analyzing computer generated images containing varying degrees of simulated intercellular junction disruption. Accurate IJOQ analysis was further confirmed using images generated from in vitro and in vivo bacterial infection models. When compared in parallel to a previously published, semi-automated script used to measure intercellular junction organization, IJOQ demonstrated superior analysis for all in vitro and in vivo experiments described herein. These data indicate that IJOQ is an unbiased, easy-to-use tool for fluorescence microscopy analysis and will serve as a valuable, automated resource to rapidly quantify intercellular junction disruption under diverse experimental conditions.

[Supra-on state freezing of gait: two case reports]. / Congelacion de la marcha en supra-on: a proposito de dos casos.

INTRODUCTION: Over recent years, several types of freezing of gait (FOG) have been described, mainly according to their response to levodopa. FOG in Parkinson's disease presents in a variety of ways due to differences within the underlying pathophysiology. In a number of patients, increasing the dopaminergic stimulation may not improve this condition, and may even worsen it. CASE REPORTS: We present two patients with Parkinson's disease who were evaluated during off, on and supra-on periods. Motor function was assessed with Unified Parkinson's Disease Rating Scale III, tapping test on lower limbs and quantification of FOG episodes during each of these periods. Both patients presented FOG episodes while in off period, experiencing a significant improvement during on period. However, when increasing the dopaminergic stimulation in order to try to improve their motor response, FOG episodes worsened to the point of impairing gait. CONCLUSIONS: FOG episodes are not always a consequence of akinesia or rigidity. Regarding the pathophysiology, the lack of an appropriate response to treatment would be explained by the involvement of structures exceeding the substantia nigra and the dopaminergic deficit. FOG worsening during periods of dopaminergic overstimulation could be related to a neurotransmitters disbalance affecting other nuclei involved in postural and gait control.

TITLE: Congelacion de la marcha en supra-on: a proposito de dos casos.Introduccion. Durante los ultimos años se han descrito diversos tipos de congelacion de la marcha (CDM), definidos fundamentalmente por su respuesta o no al tratamiento con levodopa. El fenomeno de la CDM en la enfermedad de Parkinson es de presentacion muy variable de unos pacientes a otros, con sustrato fisiopatologico diverso. En algunos pacientes, el aumento del estimulo dopaminergico no solo no mejora, sino que puede empeorar este problema. Casos clinicos. Se presentan dos pacientes con enfermedad de Parkinson que fueron evaluados en situacion off, on y supra-on. Para la evaluacion motora se utilizo la Unified Parkinson's Disease Rating Scale III (bilateral) y el tapping test en las extremidades inferiores, y se cuantificaron los episodios de CDM que presentaban los pacientes en las tres situaciones. Ambos pacientes sufrian episodios de CDM en situacion off que no mejoraban significativamente durante el on. Al aumentar el estimulo dopaminergico, en un intento de mejorar la respuesta motora, empeoraron significativamente los episodios de CDM, hasta el punto de imposibilitar la marcha por graves bloqueos. Conclusiones. Los episodios de CDM no siempre son una mera consecuencia de la acinesia o la rigidez. En la fisiopatologia de la CDM podrian intervenir estructuras que desbordan la sustancia negra y el deficit dopaminergico, lo cual podria explicar la falta de respuesta adecuada al tratamiento e incluso el empeoramiento por desequilibrio de los neurotransmisores, en relacion con la sobreestimulacion dopaminergica, en otros nucleos implicados en el control postural y de la marcha.

[Abnormal movements of peripheral origin: seven case reports]. / Movimientos anormales de origen periferico: a proposito de siete casos.

INTRODUCTION: Movement disorders induced by central nervous system trauma are well recognized. The relation between peripheral injury and the subsequent development of movement disorders has been documented in many reports, specially dystonia and tremor. Pathophysiological mechanisms underlying these movement disorders are not well understood. CASE REPORTS: We report a group of seven patients with movement disorders induced by peripheral trauma. The inclusion criteria used for the patients were: the trauma was well documented for the patient and the medical history, and the onset of the movement disorder was anatomically and temporally related to the injury. We describe seven patients presenting respectively oromandibular dystonia, radicular myoclonus, tremor, segmental dystonia, lower limbs dystonia, segmental myoclonus and tremor, of the body parts previously exposed to traumatic injuries. CONCLUSIONS: Individual predisposition and central changes with pathological reorganization in response to peripheral injury have been considered in the pathogenesis of peripherally induced movements disorders.