Small intestine and colon tissue-resident memory CD8+ T cells exhibit molecular heterogeneity and differential dependence on Eomes.

Tissue-resident memory CD8+ T (TRM) cells are a subset of memory T cells that play a critical role in limiting early pathogen spread and controlling infection. TRM cells exhibit differences across tissues, but their potential heterogeneity among distinct anatomic compartments within the small intestine and colon has not been well recognized. Here, by analyzing TRM cells from the lamina propria and epithelial compartments of the small intestine and colon, we showed that intestinal TRM cells exhibited distinctive patterns of cytokine and granzyme expression along with substantial transcriptional, epigenetic, and functional heterogeneity. The T-box transcription factor Eomes, which represses TRM cell formation in some tissues, exhibited unexpected context-specific regulatory roles in supporting the maintenance of established TRM cells in the small intestine, but not in the colon. Taken together, these data provide previously unappreciated insights into the heterogeneity and differential requirements for the formation vs. maintenance of intestinal TRM cells.

Early transcriptional and epigenetic divergence of CD8+ T cells responding to acute versus chronic infection.

During a microbial infection, responding CD8+ T cells give rise to effector cells that provide acute host defense and memory cells that provide sustained protection. An alternative outcome is exhaustion, a state of T cell dysfunction that occurs in the context of chronic infections and cancer. Although it is evident that exhausted CD8+ T (TEX) cells are phenotypically and molecularly distinct from effector and memory CD8+ T cells, the factors regulating the earliest events in the differentiation process of TEX cells remain incompletely understood. Here, we performed single-cell RNA-sequencing and single-cell ATAC-sequencing of CD8+ T cells responding to LCMV-Armstrong (LCMV-Arm) or LCMV-Clone 13 (LCMV-Cl13), which result in acute or chronic infections, respectively. Compared to CD8+ T cells that had undergone their first division in response to LCMV-Arm (Div1ARM) cells, CD8+ T cells that had undergone their first division in response to LCMV-Cl13 (Div1CL13) expressed higher levels of genes encoding transcription factors previously associated with exhaustion, along with higher levels of Ezh2, the catalytic component of the Polycomb Repressive Complex 2 (PRC2) complex, which mediates epigenetic silencing. Modulation of Ezh2 resulted in altered expression of exhaustion-associated molecules by CD8+ T cells responding to LCMV-Cl13, though the specific cellular and infectious contexts, rather than simply the level of Ezh2 expression, likely determine the eventual outcome. Taken together, these findings suggest that the differentiation paths of CD8+ T cells responding to acute versus chronic infections may diverge earlier than previously appreciated.

Psychometric and Clinimetric Properties of the Melbourne Assessment 2 in Children With Cerebral Palsy.

OBJECTIVE: To examine the psychometric and clinimetric properties of the Melbourne Assessment 2 (MA2), an outcome measurement that is increasingly used in clinical studies. DESIGN: Psychometric and clinimetric study. SETTING: Community. PARTICIPANTS: Seventeen children with cerebral palsy (CP) from 5 to 12 years were recruited for the estimation of the test-retest reliability and minimal detectable change (MDC). Thirty-five children with CP were recruited to receive an 8-week intensive neurorehabilitation intervention to estimate the validity, responsiveness, and minimal clinically important difference (MCID). INTERVENTIONS: Thirty-five children with CP received upper limb neurorehabilitation programs for 8 weeks. MAIN OUTCOME MEASURES: The MA2 and the criterion measures, including the Bruininks-Oseretsky Test of Motor Proficiency, 2nd edition (BOT-2), the Box and Blocks Test (BBT), and the Pediatric Motor Activity Log-Revised (PMAL-R), were evaluated at pretreatment and posttreatment. RESULTS: The MA2 has 4 subscales: range of motion, fluency, accuracy, and dexterity. The test-retest reliability of the MA2 is high (intraclass correlation coefficient, .92-.98). The significant relationships between the MA2 and BBT, BOT-2, and PMAL-R support its validity. The significance of paired t test results (P<.001) and large magnitudes of the standardized response mean (1.70-2.00) confirm the responsiveness of the MA2. The MDC values of the 4 subscales of the MA2 are 2.85, 1.63, 1.97, and 1.84, respectively, and the suggested MCID values of these 4 subscales are 2.35, 3.20, 2.09, and 2.22, respectively, indicating the minimum scores of improvement to be interpreted as both statistically significant and clinically important. CONCLUSIONS: The study findings indicate that the MA2 has sound psychometric and clinimetric properties and is thus an adequate measurement for research and clinical applications.

Molecular weaponry: diverse effectors delivered by the Type VI secretion system.

The Type VI secretion system is a widespread bacterial nanomachine, used to deliver toxins directly into eukaryotic or prokaryotic target cells. These secreted toxins, or effectors, act on diverse cellular targets, and their action provides the attacking bacterial cell with a significant fitness advantage, either against rival bacteria or eukaryotic host organisms. In this review, we discuss the delivery of diverse effectors by the Type VI secretion system, the modes of action of the so-called 'anti-bacterial' and 'anti-eukaryotic' effectors, the mechanism of self-resistance against anti-bacterial effectors and the evolutionary implications of horizontal transfer of Type VI secretion system-associated toxins. Whilst it is likely that many more effectors remain to be identified, it is already clear that toxins delivered by this secretion system represent efficient weapons against both bacteria and eukaryotes.

Efficient estimation of a Cox model when integrating the subgroup incidence rate information.

Incidence rates for diseases are widely used in the field of medical research because they lead to clear and simple physical and clinical interpretations. In this study, we propose an efficient estimation method that incorporates auxiliary subgroup information related to the incidence rate into the estimation of the Cox proportional hazard model. The results show that utilizing the incidence rate information improves the efficiency of the estimation of regression parameters based on the double empirical likelihood method compared to that for conventional models that do not incorporation such information. We show that estimators of regression parameters asymptotically follow a multivariate normal distribution with a variance-covariance matrix that can be consistently estimated. Simulation results indicate that the proposed estimators significantly increase efficiency. Finally, an example of the effects of type 2 diabetes on stroke is applied to demonstrate the proposed method.

Perception of the Use of the Direct Observation of Procedural Skills in Occupational Therapy Postgraduate Year Training in Taiwan: Survey of the Perspectives of Trainees and Supervisors.

Introduction: Assessment of clinical competence is a significant part of the training for young occupational therapists (OTs). Objective and systematic assessment allows both supervisors and trainees to be aware of the training objectives and monitor the progress. The direct observation of procedural skills (DOPS) is a work-based assessment to evaluate professional knowledge, skills, and attitude in clinical training. This study investigated the perspectives of OT educators and trainees on using DOPS and their discrepancy for OT postgraduate year (PGY) training. Methods: This study used a quantitative online survey. Eighty-six supervisors and 41 trainees of OT PGY training programs from 95 hospitals returned the questionnaire (a 90.5% return rate), and 64 supervisors and 30 trainees who used DOPS were analyzed. Outcomes included the practicality in using the DOPS in clinical settings, the ease of rating the DOPS, and advantages and the disadvantages of the DOPS. Results: Most respondents reported that completing one DOPS required at least 11 minutes for direct observation (11-40 minutes: teacher 92.2%; trainee 80.6%). Most respondents (teacher 96.9%, trainee 96.8%) had feedback after direct observation of DOPS, and about half of the feedback assessments took 5 to 10 minutes (teacher 53.1%, trainee 48.4%). Most OT educators and trainees agreed that clinical resources were sufficient and that DOPS matched with OT training goals, benefited OT competence training, and had a fair, objective, and consistent scoring system. Significantly higher percentages of OT trainees felt stressed in and satisfied with the DOPS assessment than trainers. Differences between teachers and trainees regarding easiness of rating DOPS items were not significant. Conclusion: Most OT educators and trainees agreed that DOPS was a practical and appropriate assessment for OT PGY training.

Effects of Intensive Versus Distributed Constraint-Induced Movement Therapy for Children With Unilateral Cerebral Palsy: A Quasi-Randomized Trial.

BACKGROUND: Previous studies have compared the effectiveness of constraint-induced movement therapy (CIMT) by different training doses. However, whether the dosing schedule, that is, intensive or distributed, influences the effectiveness of CIMT in children with unilateral cerebral palsy (CP) is unknown. OBJECTIVE: To investigate the effectiveness of intensive and distributed CIMT for children with unilateral CP. METHODS: Fifty children with unilateral CP were assigned to intensive or distributed CIMT group with a total of 36 training hours. The intensive CIMT was delivered within 1 week, and the distributed CIMT was delivered twice a week for 8 weeks. The outcomes were the Melbourne Assessment 2, Box and Block Test, Pediatric Motor Activity Log-Revised (PMAL-R), Bruininks-Oseretsky test of motor proficiency 2, ABILHAND-Kids and Parenting Stress Index-Short Form. The intensive group was assessed at the initiation of treatment (week 0), at the end of 1 week treatment (week 1), and 8 weeks after the initiation of treatment (week 8). The distributed group was assessed at week 0 and week 8. RESULTS: The within-group analyses demonstrated significant differences on all motor outcomes. There were no significant between-group differences at post-treatment, while the intensive CIMT demonstrated larger improvements than the distributed CIMT did on quality of use of the more-affected hand, as rated by parents on the PMAL-R at week 8. CONCLUSIONS: The 2 dosing schedules of CIMT had similar effectiveness for children with unilateral CP. The intensive CIMT yielded additional improvement on parent rated motor quality of the more-affected hand at 8 weeks after the initiation of treatment. TRIAL REGISTRATION: ClinicalTrials.gov (ID: NCT03128385).

Occupational evaluation of community-based psychiatric rehabilitation outcomes in individuals with severe mental illnesses: A ten-year retrospective study.

BACKGROUND: There is a lack of research on the effect of community-based psychiatric rehabilitation programs (CBPRs) in individuals with severe mental illness. This research used data from a retrospective study to examine the effect of a CBPR in a community rehabilitation center. MATERIALS AND METHODS: Clinical outcomes measures from a retrospective study were collected. Outcome measures were the Allen Cognitive Level Screen assessment, Purdue Pegboard Test, Chu's Attention Test, and Activities of Daily Living Rating Scale-III (ADLRS-III) before and immediately after 12 months of intervention. RESULTS: The 141 participants with mental illness were an average age of 35.29 years (SD = 8.75). The retrospective review of medical records showed 46 people dropped out within 12 months, and 95 people continued to participate in the rehabilitation program for 1 year. After 1 year of community rehabilitation, there was a trend for the participants who completed the intervention to improve on the ADLRS-III, Purdue Pegboard Test, and Chu's Attention Test. Participants who performed better on the occupational assessment were more likely to transit to the employment status. CONCLUSION: This study found the benefits of CBPR in work-related intervention for people with mental illness. Occupational assessments are relevant for studying changes in functional outcomes in people with mental illness receiving community-based rehabilitation.

Indoor CO2 monitoring in a surgical intensive care unit under visitation restrictions during the COVID-19 pandemic.

Background: Indoor CO2 concentration is an important metric of indoor air quality (IAQ). The dynamic temporal pattern of CO2 levels in intensive care units (ICUs), where healthcare providers experience high cognitive load and occupant numbers are frequently changing, has not been comprehensively characterized. Objective: We attempted to describe the dynamic change in CO2 levels in the ICU using an Internet of Things-based (IoT-based) monitoring system. Specifically, given that the COVID-19 pandemic makes hospital visitation restrictions necessary worldwide, this study aimed to appraise the impact of visitation restrictions on CO2 levels in the ICU. Methods: Since February 2020, an IoT-based intelligent indoor environment monitoring system has been implemented in a 24-bed university hospital ICU, which is symmetrically divided into areas A and B. One sensor was placed at the workstation of each area for continuous monitoring. The data of CO2 and other pollutants (e.g., PM2.5) measured under standard and restricted visitation policies during the COVID-19 pandemic were retrieved for analysis. Additionally, the CO2 levels were compared between workdays and non-working days and between areas A and B. Results: The median CO2 level (interquartile range [IQR]) was 616 (524-682) ppm, and only 979 (0.34%) data points obtained in area A during standard visitation were ≥ 1,000 ppm. The CO2 concentrations were significantly lower during restricted visitation (median [IQR]: 576 [556-596] ppm) than during standard visitation (628 [602-663] ppm; p < 0.001). The PM2.5 concentrations were significantly lower during restricted visitation (median [IQR]: 1 [0-1] µg/m3) than during standard visitation (2 [1-3] µg/m3; p < 0.001). The daily CO2 and PM2.5 levels were relatively low at night and elevated as the occupant number increased during clinical handover and visitation. The CO2 concentrations were significantly higher in area A (median [IQR]: 681 [653-712] ppm) than in area B (524 [504-547] ppm; p < 0.001). The CO2 concentrations were significantly lower on non-working days (median [IQR]: 606 [587-671] ppm) than on workdays (583 [573-600] ppm; p < 0.001). Conclusion: Our study suggests that visitation restrictions during the COVID-19 pandemic may affect CO2 levels in the ICU. Implantation of the IoT-based IAQ sensing network system may facilitate the monitoring of indoor CO2 levels.

Responsiveness to Vedolizumab Therapy in Ulcerative Colitis is Associated With Alterations in Immune Cell-Cell Communications.

BACKGROUND: Ulcerative colitis (UC) and Crohn's disease are 2 types of inflammatory bowel disease (IBD), a group of chronic digestive disorders caused by aberrant immune responses to intestinal microbes. Although changes in the composition of immune cell subsets in the context of IBD have been previously described, the interactions and communication among cells are less well understood. Moreover, the precise mechanisms of action underlying many biologic therapies, including the anti-α4ß7 integrin antagonist vedolizumab, remain incompletely understood. Our study aimed to explore possible additional mechanisms through which vedolizumab acts. METHODS: We performed cellular indexing of transcriptomes and epitopes by sequencing (CITE-seq) on peripheral blood and colon immune cells derived from patients with ulcerative colitis treated with the anti-α4ß7 integrin antagonist vedolizumab. We applied a previously published computational approach, NicheNet, to predict immune cell-cell interactions, revealing putative ligand-receptor pairs and key transcriptional changes downstream of these cell-cell communications (CCC). RESULTS: We observed decreased proportions of T helper 17 (TH17) cells in UC patients who responded to vedolizumab and therefore focused the study on identifying cell-cell communications and signals of TH17 cells with other immune cells. For example, we observed that colon TH17 cells from vedolizumab nonresponders were predicted to have a greater degree of interactions with classical monocytes compared with responders, whereas colon TH17 cells from vedolizumab responders exhibited more interactions with myeloid dendritic cells compared with nonresponders. CONCLUSIONS: Overall, our results indicate that efforts to elucidate cell-cell communications among immune and nonimmune cell types may increase the mechanistic understanding of current and investigational therapies for IBD.

Compared to ulcerative patients unresponsive to vedolizumab, immune cell networks of ulcerative colitis patients responsive to vedolizumab have decreased proportion of TH17 and less pro-inflammatory signaling in the gut. Decreased pro-TH17 and interleukin (IL)-1 signaling from classical monocytes and innate immunocytes may mediate this phenotype.

Identification of CD8 + T-Cell-Immune Cell Communications in Ileal Crohn's Disease.

INTRODUCTION: Crohn's disease (CD) is a major subtype of inflammatory bowel disease (IBD), a spectrum of chronic intestinal disorders caused by dysregulated immune responses to gut microbiota. Although transcriptional and functional changes in a number of immune cell types have been implicated in the pathogenesis of IBD, the cellular interactions and signals that drive these changes have been less well-studied. METHODS: We performed Cellular Indexing of Transcriptomes and Epitopes by sequencing on peripheral blood, colon, and ileal immune cells derived from healthy subjects and patients with CD. We applied a previously published computational approach, NicheNet, to predict immune cell types interacting with CD8 + T-cell subsets, revealing putative ligand-receptor pairs and key transcriptional changes downstream of these cell-cell communications. RESULTS: As a number of recent studies have revealed a potential role for CD8 + T-cell subsets in the pathogenesis of IBD, we focused our analyses on identifying the interactions of CD8 + T-cell subsets with other immune cells in the intestinal tissue microenvironment. We identified ligands and signaling pathways that have implicated in IBD, such as interleukin-1ß, supporting the validity of the approach, along with unexpected ligands, such as granzyme B, which may play previously unappreciated roles in IBD. DISCUSSION: Overall, these findings suggest that future efforts focused on elucidating cell-cell communications among immune and nonimmune cell types may further our understanding of IBD pathogenesis.

A Prediction Model for Tumor Recurrence in Stage II-III Colorectal Cancer Patients: From a Machine Learning Model to Genomic Profiling.

BACKGROUND: Colorectal cancer (CRC) is one of the most prevalent malignant diseases worldwide. Risk prediction for tumor recurrence is important for making effective treatment decisions and for the survival outcomes of patients with CRC after surgery. Herein, we aimed to explore a prediction algorithm and the risk factors for postoperative tumor recurrence using a machine learning (ML) approach with standardized pathology reports for patients with stage II and III CRC. METHODS: Pertinent clinicopathological features were compiled from medical records and standardized pathology reports of patients with stage II and III CRC. Four ML models based on logistic regression (LR), random forest (RF), classification and regression decision trees (CARTs), and support vector machine (SVM) were applied for the development of the prediction algorithm. The area under the curve (AUC) of the ML models was determined in order to compare the prediction accuracy. Genomic studies were performed using a panel-targeted next-generation sequencing approach. RESULTS: A total of 1073 patients who received curative intent surgery at the National Cheng Kung University Hospital between January 2004 and January 2019 were included. Based on conventional statistical methods, chemotherapy (p = 0.003), endophytic tumor configuration (p = 0.008), TNM stage III disease (p < 0.001), pT4 (p < 0.001), pN2 (p < 0.001), increased numbers of lymph node metastases (p < 0.001), higher lymph node ratios (LNR) (p < 0.001), lymphovascular invasion (p < 0.001), perineural invasion (p < 0.001), tumor budding (p = 0.004), and neoadjuvant chemoradiotherapy (p = 0.025) were found to be correlated with the tumor recurrence of patients with stage II-III CRC. While comparing the performance of different ML models for predicting cancer recurrence, the AUCs for LR, RF, CART, and SVM were found to be 0.678, 0.639, 0.593, and 0.581, respectively. The LR model had a better accuracy value of 0.87 and a specificity value of 1 in the testing set. Two prognostic factors, age and LNR, were selected by multivariable analysis and the four ML models. In terms of age, older patients received fewer cycles of chemotherapy and radiotherapy (p < 0.001). Right-sided colon tumors (p = 0.002), larger tumor sizes (p = 0.008) and tumor volumes (p = 0.049), TNM stage II disease (p < 0.001), and advanced pT3-4 stage diseases (p = 0.04) were found to be correlated with the older age of patients. However, pN2 diseases (p = 0.005), lymph node metastasis number (p = 0.001), LNR (p = 0.004), perineural invasion (p = 0.018), and overall survival rate (p < 0.001) were found to be decreased in older patients. Furthermore, PIK3CA and DNMT3A mutations (p = 0.032 and 0.039, respectively) were more frequently found in older patients with stage II-III CRC compared to their younger counterparts. CONCLUSIONS: This study demonstrated that ML models have a comparable predictive power for determining cancer recurrence in patients with stage II-III CRC after surgery. Advanced age and high LNR were significant risk factors for cancer recurrence, as determined by ML algorithms and multivariable analyses. Distinctive genomic profiles may contribute to discrete clinical behaviors and survival outcomes between patients of different age groups. Studies incorporating complete molecular and genomic profiles in cancer prediction models are beneficial for patients with stage II-III CRC.

Intercorrelations between the Personal and Social Performance Scale, cognitive function, and activities of daily living.

The aim of this study was to evaluate the intercorrelation between the Personal and Social Performance (PSP) score, cognitive function, and activities of daily living (ADLs). Twenty patients with chronic schizophrenia were recruited; the PSP and ADL scales and psychological assessments including the Wisconsin Card Sorting Test, the Wechsler Memory Scale-Revised (WMS-R), and the Continuous Performance Test (CPT) were administered. Positive correlations between the total PSP scale score and performance in the WMS-R, CPT, and ADL scores were identified. The PSP score was found to be of good reliability for cognitive function and ADL evaluation.

Relationship between hemispatial inattention and performance of activities of daily living in patients with schizophrenia.

This study investigated the relation of hemispatial inattention to the performance of daily functions in 32 patients with schizophrenia or schizoaffective disorder and in 31 healthy controls. They were tested on the relationship between a target cancellation task and the Activities of Daily Living Rating Scale-II (ADLRS-II). According to the results of the hemispatial inattention test, the patients with schizophrenia made more omissions in the cancellation test than the controls. In addition, the results showed a significant correlation between number of omissions on the cancellation test and the ADLRS-II score in the study participants. A statistically significant relationship was observed between hemispatial inattention and the functional status of patients with schizophrenia, and suggests the need to incorporate measures of visual attention into psychiatric rehabilitation assessments.

Association of visual motor processing and social cognition in schizophrenia.

Patients with schizophrenia have difficulties in social cognitive domains including emotion recognition and mentalization, and in sensorimotor processing and learning. The relationship between social cognitive deficits and sensorimotor function in patients with schizophrenia remains largely unexplored. With the hypothesis that impaired visual motor processing may decelerate information processing and subsequently affects various domains of social cognition, we examined the association of nonverbal emotion recognition, mentalization, and visual motor processing in schizophrenia. The study examined mentalization using the verbal subset of the Chinese version of Theory of Mind (CToM) Task, an equivalent task of the Faux Pas Test; emotion recognition using the Diagnostic Analysis of Nonverbal Accuracy 2-Taiwan version (DANVA-2-TW), and visual motor processing using a joystick tracking task controlled for basic motor function in 34 individuals with chronic schizophrenia in the community and 42 healthy controls. Patients with schizophrenia had significantly worse performance than healthy controls in social cognition, including facial, prosodic emotion recognition, and mentalization. Visual motor processing was also significantly worse in patients with schizophrenia. Only in patients with schizophrenia, both emotion recognition (mainly in prosodic modality, happy, and sad emotions) and mentalization were positively associated with their learning capacity of visual motor processing. These findings suggest a prospective role of sensorimotor function in their social cognitive deficits. Despite that the underlying neural mechanism needs further research, our findings may provide a new direction for restoration of social cognitive function in schizophrenia by enhancing visual motor processing ability.

Effects of adding a concurrent cognitive task on manual dexterity in people with schizophrenia: Implications for performance of daily life activities.

This study investigated the effect of dual task performance of hand dexterity tasks and the relationship to daily functioning in 40 people with chronic schizophrenia and 35 healthy participants. Participants performed the Purdue Pegboard Test, O'Connor Finger Dexterity Test, and the Serial Subtracting Seven Task as the secondary task under single- and dual-task conditions and completed the Activities of Daily Living Rating Scale-III (ADLRS-III). The hand dexterity of all participants declined from the single to the dual tasks, and the discrepancy between single- and dual-task performance was significantly greater in the schizophrenia group than in the control group. Significant condition and group effects were found for both hand dexterity tests. People with schizophrenia who took longer time in performing hand dexterity tasks had significantly worse daily life function. Negative correlations were noted between discrepancy of dual tasking and the ADLRS-III score in the schizophrenic group. Deficits in dual-task performance of hand dexterity is significant in people with schizophrenia and is related to daily life performance. Occupational therapy practitioners can consider using dual tasks as a therapeutic activity for people with schizophrenia to promote functional abilities in real-world environments.

Corrigendum: Contribution of the Alkylquinolone Quorum-Sensing System to the Interaction of Pseudomonas Aeruginosa With Bronchial Epithelial Cells.

[This corrects the article DOI: 10.3389/fmicb.2018.03018.].

The type VI secretion system deploys antifungal effectors against microbial competitors.

Interactions between bacterial and fungal cells shape many polymicrobial communities. Bacteria elaborate diverse strategies to interact and compete with other organisms, including the deployment of protein secretion systems. The type VI secretion system (T6SS) delivers toxic effector proteins into host eukaryotic cells and competitor bacterial cells, but, surprisingly, T6SS-delivered effectors targeting fungal cells have not been reported. Here we show that the 'antibacterial' T6SS of Serratia marcescens can act against fungal cells, including pathogenic Candida species, and identify the previously undescribed effector proteins responsible. These antifungal effectors, Tfe1 and Tfe2, have distinct impacts on the target cell, but both can ultimately cause fungal cell death. 'In competition' proteomics analysis revealed that T6SS-mediated delivery of Tfe2 disrupts nutrient uptake and amino acid metabolism in fungal cells, and leads to the induction of autophagy. Intoxication by Tfe1, in contrast, causes a loss of plasma membrane potential. Our findings extend the repertoire of the T6SS and suggest that antifungal T6SSs represent widespread and important determinants of the outcome of bacterial-fungal interactions.

Contribution of the Alkylquinolone Quorum-Sensing System to the Interaction of Pseudomonas aeruginosa With Bronchial Epithelial Cells.

Pseudomonas aeruginosa causes infections in patients with compromised epithelial barrier function. Multiple virulence factors produced by P. aeruginosa are controlled by quorum sensing (QS) via 2-alkyl-4(1H)-quinolone (AQ) signal molecules. Here, we investigated the impact of AQs on P. aeruginosa PAO1 infection of differentiated human bronchial epithelial cells (HBECs). The pqsA-E operon is responsible for the biosynthesis of AQs including the 2-alkyl-3-hydroxy-4-quinolones, 4-hydroxy-2-alkylquinolines, and 4-hydroxy-2-alkylquinoline N-oxides as exemplified by pseudomonas quinolone signal (PQS), 2-heptyl-4-hydroxyquinoline (HHQ), and 2-heptyl-4-hydroxyquinoline N-oxide (HQNO), respectively. PQS and HHQ both act as QS signal molecules while HQNO is a cytochrome inhibitor. PqsE contributes both to AQ biosynthesis and promotes virulence in a PQS-independent manner. Our results show that PQS, HHQ, and HQNO were produced during PAO1 infection of HBECs, but no differences in growth or cytotoxicity were apparent when PAO1 and an AQ-negative ΔpqsA mutant were compared. Both strains promoted synthesis of inflammatory cytokines TNF-α, interleukin (IL)-6, and IL-17C by HBECs, and the provision of exogenous PQS negatively impacted on this response without affecting bacterial growth. Expression of pqsE and the PQS-independent PqsE-regulated genes mexG and lecA was detected during HBEC infection. Levels were reduced in the ΔpqsA mutant, that is, in the absence of PQS, and increased by exogenous PQS. These results support an AQ-independent role for PqsE during initial infection of HBEC by P. aeruginosa and for PQS as an enhancer of PqsE and PqsE-controlled virulence determinants and as an immunomodulator.

Inhibiting N-acyl-homoserine lactone synthesis and quenching Pseudomonas quinolone quorum sensing to attenuate virulence.

Bacteria sense their own population size, tune the expression of responding genes, and behave accordingly to environmental stimuli by secreting signaling molecules. This phenomenon is termed as quorum sensing (QS). By exogenously manipulating the signal transduction bacterial population behaviors could be controlled, which may be done through quorum quenching (QQ). QS related regulatory networks have been proven their involvement in regulating many virulence determinants in pathogenic bacteria in the course of infections. Interfering with QS signaling system could be a novel strategy against bacterial infections and therefore requires more understanding of their fundamental mechanisms. Here we review the development of studies specifically on the inhibition of production of N-acyl-homoserine lactone (AHL), a common proteobacterial QS signal. The opportunistic pathogen, Pseudomonas aeruginosa, equips the alkylquinolone (AQ)-mediated QS which also plays crucial roles in its pathogenicity. The studies in QQ targeting on AQ are also discussed.