NF-κB signaling in neoplastic transition from epithelial to mesenchymal phenotype.

NF-κB transcription factors are critical regulators of innate and adaptive immunity and major mediators of inflammatory signaling. The NF-κB signaling is dysregulated in a significant number of cancers and drives malignant transformation through maintenance of constitutive pro-survival signaling and downregulation of apoptosis. Overactive NF-κB signaling results in overexpression of pro-inflammatory cytokines, chemokines and/or growth factors leading to accumulation of proliferative signals together with activation of innate and select adaptive immune cells. This state of chronic inflammation is now thought to be linked to induction of malignant transformation, angiogenesis, metastasis, subversion of adaptive immunity, and therapy resistance. Moreover, accumulating evidence indicates the involvement of NF-κB signaling in induction and maintenance of invasive phenotypes linked to epithelial to mesenchymal transition (EMT) and metastasis. In this review we summarize reported links of NF-κB signaling to sequential steps of transition from epithelial to mesenchymal phenotypes. Understanding the involvement of NF-κB in EMT regulation may contribute to formulating optimized therapeutic strategies in cancer. Video Abstract.

Iatrogenic Neonatal Esophageal Perforation: A European Multicentre Review on Management and Outcomes.

BACKGROUND: The aim of this multicenter retrospective study and literature review was to review management and outcomes of neonatal esophageal perforation (NEP). METHODS: Protocol data were collected from four European Centers on gestational age, factors surrounding feeding tube insertion, management and outcomes. RESULTS: The 5-year study period (2014-2018) identified eight neonates with median gestational age of 26 + 4 weeks (23 + 4-39) and median birth weight 636 g (511-3500). All patients had NEP from enterogastric tube insertions, with the perforation occurring at median 1st day of life (range 0-25). Seven/eight patients were ventilated (two/seven-high frequency oscillation). NEP became apparent on first tube placement (n = 1), first change (n = 5), and after multiple changes (n = 2). Site of perforation was known in six (distal n = 3, proximal n = 2 and middle n = 1). Diagnosis was established by respiratory distress (n = 4), respiratory distress and sepsis (n = 2) and post-insertion chest X-ray (n = 2). Management in all patients included antibiotics and parenteral nutrition with two/eight receiving steroids and ranitidine, one/eight steroids only and one/eight ranitidine only. One neonate had a gastrostomy inserted, while in another an enterogastric tube was orally successfully re-inserted. Two neonates developed pleural effusion and/or mediastinal abscess requiring chest tube. Three neonates had significant morbidities (related to prematurity) and there was one death 10 days post-perforation (related to prematurity complications). CONCLUSIONS: NEP during NGT insertion is rare even in premature infants after evaluating data from four tertiary centers and reviewing the literature. In this small cohort, conservative management seems to be safe. A larger sample size will be necessary to answer questions on efficacy of antibiotics, antacids and NGT re-insertion time frame in NEP.

Critical Point-of-care Ultrasound Diagnosis of Fournier's Gangrene: A Case Report.

INTRODUCTION: Fournier's gangrene is a severe, necrotizing, and potentially fatal, soft tissue infection of the perineum that can be difficult to diagnose clinically. Point-of-care ultrasound (POCUS) has established a critical role in emergency medicine as a quick diagnostic tool due to its safety, accuracy, and cost effectiveness. CASE REPORT: We present a case in which POCUS was used to rapidly confirm diagnosis in an unstable, severely septic patient presenting to the emergency department with Fournier's gangrene. CONCLUSION: Point-of-care ultrasound can be used to make the diagnosis of Fournier's gangrene in critical patients when other diagnostic modalities are not feasible due to a patient's clinical state.

Abdominal Pain in the Elderly Patient: Point-of-care Ultrasound Diagnosis of Small Bowel Obstruction.

CASE PRESENTATION: A 67-year-old female presented to the emergency department (ED) complaining of generalized abdominal pain, nausea, and vomiting. Point-of-care ultrasound (POCUS) demonstrated dilated bowel loops measuring up to 4.1 centimeters and localized free fluid, consistent with a small bowel obstruction (SBO). A nasogastric tube was placed without complications. The patient was admitted to the hospital and conservatively managed with an uncomplicated course. DISCUSSION: In elderly patients with abdominal pain, POCUS is an excellent initial imaging modality to assist emergency physicians in rapid and accurate diagnosis of a variety of pathologies to expedite management. Point-of-care ultrasound can be used to rule out and evaluate for conditions encountered in emergency medicine, including acute cholecystitis, renal colic, abdominal aortic aneurysm, and intraperitoneal free fluid. As demonstrated in our case presentation, POCUS had an integral role in the early diagnosis and management of a SBO.

Listeria monocytogenes Exploits Host Caveolin for Cell-to-Cell Spreading.

Listeria monocytogenes moves from one cell to another using actin-rich membrane protrusions that propel the bacterium toward neighboring cells. Despite cholesterol being required for this transfer process, the precise host internalization mechanism remains elusive. Here, we show that caveolin endocytosis is key to this event as bacterial cell-to-cell transfer is severely impaired when cells are depleted of caveolin-1. Only a subset of additional caveolar components (cavin-2 and EHD2) are present at sites of bacterial transfer, and although clathrin and the clathrin-associated proteins Eps15 and AP2 are absent from the bacterial invaginations, efficient L. monocytogenes spreading requires the clathrin-interacting protein epsin-1. We also directly demonstrated that isolated L. monocytogenes membrane protrusions can trigger the recruitment of caveolar proteins in a neighboring cell. The engulfment of these bacterial and cytoskeletal structures through a caveolin-based mechanism demonstrates that the classical nanometer-scale theoretical size limit for this internalization pathway is exceeded by these bacterial pathogens.IMPORTANCEListeria monocytogenes moves from one cell to another as it disseminates within tissues. This bacterial transfer process depends on the host actin cytoskeleton as the bacterium forms motile actin-rich membranous protrusions that propel the bacteria into neighboring cells, thus forming corresponding membrane invaginations. Here, we examine these membrane invaginations and demonstrate that caveolin-1-based endocytosis is crucial for efficient bacterial cell-to-cell spreading. We show that only a subset of caveolin-associated proteins (cavin-2 and EHD2) are involved in this process. Despite the absence of clathrin at the invaginations, the classical clathrin-associated protein epsin-1 is also required for efficient bacterial spreading. Using isolated L. monocytogenes protrusions added onto naive host cells, we demonstrate that actin-based propulsion is dispensable for caveolin-1 endocytosis as the presence of the protrusion/invagination interaction alone triggers caveolin-1 recruitment in the recipient cells. Finally, we provide a model of how this caveolin-1-based internalization event can exceed the theoretical size limit for this endocytic pathway.

Guiding Cardiopulmonary Resuscitation with Focused Echocardiography: A Report of Five Cases.

Background: Focused transthoracic echocardiography has been used to determine etiologies of cardiac arrest and evaluate utility of continuing resuscitation after cardiac arrest. Few guidelines exist advising ultrasound timing within the advanced cardiac life support algorithm. Natural timing of echocardiography occurs during the pulse check, when views are unencumbered by stabilization equipment or vigorous movements. However, recent studies suggest that ultrasound performance during pulse checks prolongs the pause duration of cardiopulmonary resuscitation. Transesophageal echocardiography studies have demonstrated benefits in this regard, but there have been no transthoracic echocardiography studies assessing the physical performance of compressions during cardiopulmonary resuscitation. Objective: The purpose of this study was to describe cases where echocardiography performed at the beginning of the cardiac arrest algorithm offers actionable information to cardiopulmonary resuscitation itself without delaying provision of compressions. Conclusion: Providers using focused echocardiography to evaluate cardiac arrest patients should consider initiating scans at the start of compressions to identify the optimal location for compression delivery and to detect inadequate compressions. Subsequent visualization of full left ventricular compression may be seen after a location change, and combined with end tidal carbon dioxide values, gives indication for improved forward circulatory flow. Although it is not possible in all patients, doing so hastens provision of quality compressions that affect hemodynamic parameters without causing prolongations to the pulse check pause. Further research is needed to determine patient outcomes from both out-of-hospital and in-hospital cardiac arrest when cardiopulmonary resuscitation is visually guided by focused echocardiography.

Distribution of CD147 During Enteropathogenic Escherichia coli and Salmonella enterica Serovar Typhimurium Infections.

Enteropathogenic Escherichia coli (EPEC) and Salmonella enterica serovar Typhimurium (S. Typhimurium) are highly infectious gastrointestinal human pathogens. These microbes inject bacterial-derived effector proteins directly into the host cell cytosol as part of their disease processes. A common host subcellular target of these pathogens is the actin cytoskeleton, which is commandeered by the bacteria and is used during their attachment onto (EPEC) or invasion into (S. Typhimurium) the host cells. We previously demonstrated that the host enzyme cyclophilin A (CypA) is recruited to the actin-rich regions of EPEC pedestals and S. Typhimurium membrane ruffles. To further expand the growing catalogue of host proteins usurped by actin-hijacking bacteria, we examined the host plasma membrane protein and cognate receptor of CypA, CD147, during EPEC and S. Typhimurium infections. Here, we show that CD147 is enriched at the basolateral regions of pedestals but, unlike CypA, it is absent from their actin-rich core. We show that the CD147 recruitment to these areas requires EPEC pedestal formation and not solely bacteria-host cell contact. Additionally, we demonstrate that the depletion of CD147 by siRNA does not alter the formation of pedestals. Finally, we show that CD147 is also a component of actin-rich membrane ruffles generated during S. Typhimurium invasion of host cells. Collectively, our findings establish CD147 as another host component present at dynamic actin-rich structures formed during bacterial infections. Anat Rec, 302:2224-2232, 2019. © 2019 American Association for Anatomy.

Listeria monocytogenes hijacks CD147 to ensure proper membrane protrusion formation and efficient bacterial dissemination.

Efficient cell-to-cell transfer of Listeria monocytogenes (L. monocytogenes) requires the proper formation of actin-rich membrane protrusions. To date, only the host proteins ezrin, the binding partner of ezrin, CD44, as well as cyclophilin A (CypA) have been identified as crucial components for L. monocytogenes membrane protrusion stabilization and, thus, efficient cell-to-cell movement of the microbes. Here, we examine the classical binding partner of CypA, CD147, and find that this membrane protein is also hijacked by the bacteria for their cellular dissemination. CD147 is enriched at the plasma membrane surrounding the membrane protrusions as well as the resulting invaginations generated in neighboring cells. In cells depleted of CD147, these actin-rich structures appear similar to those generated in CypA depleted cells as they are significantly shorter and more contorted as compared to their straighter counterparts formed in wild-type control cells. The presence of malformed membrane protrusions hampers the ability of L. monocytogenes to efficiently disseminate from CD147-depleted cells. Our findings uncover another important host protein needed for L. monocytogenes membrane protrusion formation and efficient microbial dissemination.

Engineering improved T cell receptors using an alanine-scan guided T cell display selection system.

T cell receptors (TCRs) on T cells recognize peptide-major histocompatibility complex (pMHC) molecules on the surface of antigen presenting cells and this interaction determines the T cell immune response. Due to negative selection, naturally occurring TCRs bind self (tumor) peptides with low affinity and have a much higher affinity for foreign antigens. This complicates isolation of naturally occurring, high affinity TCRs that mediate more effective tumor rejection for therapeutic purposes. An attractive approach to resolve this issue is to engineer high affinity TCRs in vitro using phage, yeast or mammalian TCR display systems. A caveat of these systems is that they rely on a large library by random mutagenesis due to the lack of knowledge regarding the specific interactions between the TCR and pMHC. We have focused on the mammalian retroviral display system because it uniquely allows for direct comparison of TCR-pMHC-binding properties with T-cell activation outcomes. Through an alanine-scanning approach, we are able to quickly map the key amino acid residues directly involved in TCR-pMHC interactions thereby significantly reducing the library size. Using this method, we demonstrate that for a self-antigen-specific human TCR (R6C12) the key residues for pMHC binding are located in the CDR3ß region. This information was used as a basis for designing an efficacious TCR CDR3α library that allowed for selection of TCRs with higher avidity than the wild-type as evaluated through binding and activation experiments. This is a direct approach to target specific TCR residues in TCR library design to efficiently engineer high avidity TCRs that may potentially be used to enhance adoptive immunotherapy treatments.