Anti-Cholestatic Therapy with Obeticholic Acid Improves Short-Term Memory in Bile Duct-Ligated Mice.

Patients with cholestatic liver disease, including those with primary biliary cholangitis, can experience symptoms of impaired cognition or brain fog. This phenomenon remains unexplained and is currently untreatable. Bile duct ligation (BDL) is an established rodent model of cholestasis. In addition to liver changes, BDL animals develop cognitive symptoms early in the disease process (before development of cirrhosis and/or liver failure). The cellular mechanisms underpinning these cognitive symptoms are poorly understood. Herein, the study explored the neurocognitive symptom manifestations, and tested potential therapies, in BDL mice, and used human neuronal cell cultures to explore translatability to humans. BDL animals exhibited short-term memory loss and showed reduced astrocyte coverage of the blood-brain barrier, destabilized hippocampal network activity, and neuronal senescence. Ursodeoxycholic acid (first-line therapy for most human cholestatic diseases) did not reverse symptomatic or mechanistic aspects. In contrast, obeticholic acid (OCA), a farnesoid X receptor agonist and second-line anti-cholestatic agent, normalized memory function, suppressed blood-brain barrier changes, prevented hippocampal network deficits, and reversed neuronal senescence. Co-culture of human neuronal cells with either BDL or human cholestatic patient serum induced cellular senescence and increased mitochondrial respiration, changes that were limited again by OCA. These findings provide new insights into the mechanism of cognitive symptoms in BDL animals, suggesting that OCA therapy or farnesoid X receptor agonism could be used to limit cholestasis-induced neuronal senescence.

Sleeve Gastrectomy Protects Against Hypertension in Rats due to Changes in the Gut Microbiome.

INTRODUCTION: Sleeve gastrectomy (SG), results in improvement in hypertension. We have previously published that rodent SG improves hypertension independent of weight loss associated with unique shifts in the gut microbiome. We tested if the gut microbiome directly improves blood pressure by performing fecal material transfer (FMT) from post-SG rats to surgery-naïve animals. METHODS: We performed SG or Sham surgery in male, Zucker rats (n = 6-7) with obesity. Stool was collected postop from surgical donors for treatment of recipient rats. Three nonsurgical groups received daily, oral consumption of SG stool, sham stool, or vehicle alone (Nutella) for 10 wk (n = 7-8). FMT treatment was assessed for effects on body weight, food intake, oral glucose tolerance, and blood pressure. Genomic deoxyribonucleic acid of stool from donor and recipient groups were sequenced by 16S ribosomal ribonucleic acid and analyzed for diversity, abundance, and importance. RESULTS: Ten weeks of SG-FMT treatment significantly lowered systolic blood pressures in surgery-naïve, recipient rats compared to vehicle treatment alone (126.8 ± 13.3 mmHg versus 151.8 ± 12.2 mmHg, P = 0.001). SG-FMT treatment also significantly altered beta diversity metrics compared to Sham-FMT and vehicle treatment. In random forest analysis, amplicon sequence variant level significantly predicted FMT group, P = 0.01. CONCLUSIONS: We have found a direct link between gut microbial changes after SG and regulation of blood pressure. Future mechanistic studies are required to learn what specific gut microbial changes are required to induce improvements in obesity-associated hypertension and translation to clinical, metabolic surgery.

Nitration of chemokine CXCL8 acts as a natural mechanism to limit acute inflammation.

Chemokine CXCL8 is a key facilitator of the human host immune response, mediating neutrophil migration, and activation at the site of infection and injury. The oxidative burst is an important effector mechanism which leads to the generation of reactive nitrogen species (RNS), including peroxynitrite. The current study was performed to determine the potential for nitration to alter the biological properties of CXCL8 and its detection in human disease. Here, we show peroxynitrite nitrates CXCL8 and thereby regulates neutrophil migration and activation. The nitrated chemokine was unable to induce transendothelial neutrophil migration in vitro and failed to promote leukocyte recruitment in vivo. This reduced activity is due to impairment in both G protein-coupled receptor signaling and glycosaminoglycan binding. Using a novel antibody, nitrated CXCL8 was detected in bronchoalveolar lavage samples from patients with pneumonia. These findings were validated by mass spectrometry. Our results provide the first direct evidence of chemokine nitration in human pathophysiology and suggest a natural mechanism that limits acute inflammation.

Volumetric computed tomography measurements as predictors for outcomes in a cohort of Fournier's gangrene patients.

PURPOSE: This study evaluates the prognostic value of CT findings, including volumetric measurements, in predicting outcomes for patients with Fournier gangrene (FG), focusing on mortality, ICU admission, hospital stay length, and healthcare costs. METHODS: A retrospective study was conducted on 38 FG patients who underwent CT scans before surgical debridement. We analyzed demographic data, CT volumetric measurements, and clinical outcomes using logistic and linear regression models. RESULTS: No single CT measurement significantly predicted mortality or ICU admission. The best model for mortality prediction included age, air volume, NSTI score, and male sex, with an AUC of 0.911. Intubation likelihood was modeled with an AUC of 0.913 using age, NSTI score, and visceral to subcutaneous fat ratio. The ICU admission model achieved an AUC of 0.677. Hospital stay was predicted by air volume (ß = 0.0002656, p = 0.0505) with an adjusted R-squared of 0.1287. Air volume significantly predicted hospital costs (ß = 2.859, p = 0.00558), resulting in an adjusted R-squared of 0.2165. CONCLUSION: Volumetric CT findings provide valuable prognostic insights for FG patients, suggesting a basis for informed clinical decisions and resource allocation. Further validation in larger, multi-center studies is recommended to develop robust predictive models for FG outcomes.

Controlled CMS Data Demonstrates a Cost and Clinical Advantage for Hyperbaric Oxygen for Radiation Cystitis.

Introduction: Increasing cancer survivorship, in part due to new radiation treatments, has created a larger population at risk for delayed complications of treatment. Radiation cystitis continues to occur despite targeted radiation techniques. Materials and Methods: To investigate value-based care applying hyperbaric oxygen (HBO2) to treat delayed radiation cystitis, we reviewed public-access Medicare data from 3,309 patients from Oct 1, 2014, through Dec 31, 2019. Using novel statistical modeling, we compared cost and clinical effectiveness in a hyperbaric oxygen group to a control group receiving conventional therapies. Results: Treatment in the hyperbaric group provided a 36% reduction in urinary bleeding, a 78% reduced frequency of blood transfusion for hematuria, a 31% reduction in endoscopic procedures, and fewer hospitalizations when study patients were compared to control. There was a 53% reduction in mortality and reduced unadjusted Medicare costs of $5,059 per patient within the first year after completion of HBO2 treatment per patient. When at least 40 treatments were provided, cost savings per patient increased to $11,548 for the HBO2 study group compared to the control group. This represents a 37% reduction in Medicare spending for the HBO2-treated group. We also validate a dose-response curve effect with a complete course of 40 or more HBO2 treatments having better clinical outcomes than those treated with fewer treatments. Conclusion: These data support previous studies that demonstrate clinical benefits now with cost- effectiveness when adjunctive HBO2 treatments are added to routine interventions. The methodology provides a comparative group selected without bias. It also provides validation of statistical modeling techniques that may be valuable in future analysis, complementary to more traditional methods.

Regulation and Role of αE Integrin and Gut Homing Integrins in Migration and Retention of Intestinal Lymphocytes during Inflammatory Bowel Disease.

Targeting interactions between α4ß7 integrin and endothelial adhesion molecule MAdCAM-1 to inhibit lymphocyte migration to the gastrointestinal tract is an effective therapy in inflammatory bowel disease (IBD). Following lymphocyte entry into the mucosa, a subset of these cells expresses αEß7 integrin, which is expressed on proinflammatory lymphocytes, to increase cell retention. The factors governing lymphocyte migration into the intestinal mucosa and αE integrin expression in healthy subjects and IBD patients remain incompletely understood. We evaluated changes in factors involved in lymphocyte migration and differentiation within tissues. Both ileal and colonic tissue from active IBD patients showed upregulation of ICAM-1, VCAM-1, and MAdCAM-1 at the gene and protein levels compared with healthy subjects and/or inactive IBD patients. ß1 and ß7 integrin expression on circulating lymphocytes was similar across groups. TGF-ß1 treatment induced expression of αE on both ß7+ and ß7- T cells, suggesting that cells entering the mucosa independently of MAdCAM-1/α4ß7 can become αEß7+ ITGAE gene polymorphisms did not alter protein induction following TGF-ß1 stimulation. Increased phospho-SMAD3, which is directly downstream of TGF-ß, and increased TGF-ß-responsive gene expression were observed in the colonic mucosa of IBD patients. Finally, in vitro stimulation experiments showed that baseline ß7 expression had little effect on cytokine, chemokine, transcription factor, and effector molecule gene expression in αE+ and αE- T cells. These findings suggest cell migration to the gut mucosa may be altered in IBD and α4ß7-, and α4ß7+ T cells may upregulate αEß7 in response to TGF-ß once within the gut mucosa.

A single, peri-operative antibiotic can persistently alter the post-operative gut microbiome after Roux-en-Y gastric bypass.

INTRODUCTION: Roux-en-Y gastric bypass (RYGB) significantly alters the gut microbiome and may be a mechanism for post-operative cardiovascular disease improvement. We have previously found an association between the class of peri-operative, intravenous antibiotic administered at the time of RYGB and the resolution rate of hypertension suggesting the gut microbiome as a mechanism. In this study, we performed a prospective study of RYGB to determine if a single intravenous antibiotic could alter the gastrointestinal microbial composition. METHODS: Patients undergoing RYGB were randomized to a single, peri-operative antibiotic of intravenous cefazolin (n = 8) or clindamycin (n = 8). Stool samples were collected from four-time points: 2 weeks pre-op (- 2w), 2 days pre-op (- 2d), 2 weeks post-op (+ 2w) and 3 months post-op (+ 3m). Stool samples were processed for genomic DNA followed by Illumina 16S rRNA gene sequencing and shotgun metagenomic sequencing (MGS). RESULTS: A total of 60 stool samples (- 2w, n = 16; - 2d, n = 15; + 2w, n = 16; + 3m, n = 13) from 16 patients were analyzed. 87.5% of patients were female with an average age of 48.6 ± 12.2 years and pre-operative BMI of 50.9 ± 23.3 kg/m2. RYGB induced statistically significant differences in alpha and beta diversity. There were statistically significant differences in alpha diversity at + 2w and beta diversity at + 3m due to antibiotic treatment. MGS revealed significantly distinct gut microbiota with 11 discriminatory metagenomic assembled genomes driven by antibiotic treatment at 3 months post-op, including increased Bifidobacterium spp. with clindamycin. CONCLUSION: RYGB induces significant changes in the gut microbiome at 2 weeks that are maintained 3 months after surgery. However, the single peri-operative dose of antibiotic administered at the time of RYGB induces unique and persisting changes to the gut microbiome that are antibiotic-specific. Increased Bifidobacterium spp. with clindamycin administration may improve the metabolic efficacy of RYGB when considering gut-microbiome driven mechanisms for blood pressure resolution.

The SrrAB two-component system regulates Staphylococcus aureus pathogenicity through redox sensitive cysteines.

Staphylococcus aureus infections can lead to diseases that range from localized skin abscess to life-threatening toxic shock syndrome. The SrrAB two-component system (TCS) is a global regulator of S. aureus virulence and critical for survival under environmental conditions such as hypoxic, oxidative, and nitrosative stress found at sites of infection. Despite the critical role of SrrAB in S. aureus pathogenicity, the mechanism by which the SrrAB TCS senses and responds to these environmental signals remains unknown. Bioinformatics analysis showed that the SrrB histidine kinase contains several domains, including an extracellular Cache domain and a cytoplasmic HAMP-PAS-DHp-CA region. Here, we show that the PAS domain regulates both kinase and phosphatase enzyme activity of SrrB and present the structure of the DHp-CA catalytic core. Importantly, this structure shows a unique intramolecular cysteine disulfide bond in the ATP-binding domain that significantly affects autophosphorylation kinetics. In vitro data show that the redox state of the disulfide bond affects S. aureus biofilm formation and toxic shock syndrome toxin-1 production. Moreover, with the use of the rabbit infective endocarditis model, we demonstrate that the disulfide bond is a critical regulatory element of SrrB function during S. aureus infection. Our data support a model whereby the disulfide bond and PAS domain of SrrB sense and respond to the cellular redox environment to regulate S. aureus survival and pathogenesis.

Preoperative computed tomography in Fournier's gangrene does not delay time to surgery.

PURPOSE: Fournier's gangrene (FG), a rapidly progressive necrotizing soft tissue infection of the external genitalia and perineum, necessitates urgent surgical debridement. The time to surgery effect of preoperative computed tomography (CT) in managing this condition is yet to be fully explored. The purpose of this study was to assess whether obtaining a preoperative CT in patients with FG impacts the time to surgical intervention. METHODS: This was a single-center retrospective study of patients who underwent CT prior to surgical debridement of FG during a 9-year period vs patients who did not undergo CT. In 76 patients (male = 39, mean age = 51.8), 38 patients with FG received a preoperative CT, and 38 patients with FG did not receive CT prior to surgical debridement. Time to operating room and outcome metrics were compared between CT and non-CT groups. RESULTS: The time from hospital presentation to surgical intervention was not significantly different between patients who underwent CT and those who did not (6.65 ± 3.71 vs 5.73 ± 4.33 h, p = 0.37). There were also no significant differences in cost ($130,000 ± $102,000 vs $142,000 ± $152,000, p = 0.37), mortality (8 vs 7, p = 1), duration of hospital stay (15.5 ± 15 vs 15.7 ± 11.6 days, p = 0.95), average intensive care unit stay (5.82 ± 5.38 days vs 6.97 ± 8.58 days, p = 0.48), and APACHE score (12 ± 4.65 vs 13.9 ± 5.6, p =0.12). CONCLUSION: Obtaining a preoperative CT did not delay surgical intervention in patients with FG.

Dissecting the Therapeutic Mechanisms of Sphingosine-1-Phosphate Receptor Agonism during Ischaemia and Reperfusion.

Sphingosine 1-phosphate (S1P) and S1P receptors (S1PR) regulate many cellular processes, including lymphocyte migration and endothelial barrier function. As neutrophils are major mediators of inflammation, their transendothelial migration may be the target of therapeutic approaches to inflammatory conditions such as ischaemia-reperfusion injury (IRI). The aim of this project was to assess whether these therapeutic effects are mediated by S1P acting on neutrophils directly or indirectly through the endothelial cells. First, our murine model of peritoneum cell recruitment demonstrated the ability of S1P to reduce CXCL8-mediated neutrophil recruitment. Mechanistic in vitro studies revealed that S1P signals in neutrophils mainly through the S1PR1 and 4 receptors and induces phosphorylation of ERK1/2; however, this had no effect on neutrophil transmigration and adhesion. S1P treatment of endothelial cells significantly reduced TNF-α-induced neutrophil adhesion under flow (p < 0.01) and transendothelial migration towards CXCL8 during in vitro chemotaxis assays (p < 0.05). S1PR1 agonist CYM5442 treatment of endothelial cells also reduced neutrophil transmigration (p < 0.01) and endothelial permeability (p < 0.005), as shown using in vitro permeability assays. S1PR3 agonist had no effects on chemotaxis or permeability. In an in vivo mouse model of renal IRI, S1PR agonism with CYM5442 reduced endothelial permeability as shown by reduced Evan's Blue dye extravasation. Western blot was used to assess phosphorylation at different sites on vascular endothelial (VE)-cadherin and showed that CYM5442 reduced VEGF-mediated phosphorylation. Taken together, the results of this study suggest that reductions in neutrophil infiltration during IRI in response to S1P are mediated primarily by S1PR1 signalling on endothelial cells, possibly by altering phosphorylation of VE-cadherin. The results also demonstrate the therapeutic potential of S1PR1 agonist during IRI.

Correction: del Molino del Barrio et al. Breast Cancer: An Examination of the Potential of ACKR3 to Modify the Response of CXCR4 to CXCL12. Int. J. Mol. Sci. 2018, 19, 3592.

The authors and Editorial Office were made aware of an error in a figure within the original publication [...].

The Serum Proteome and Ursodeoxycholic Acid Response in Primary Biliary Cholangitis.

BACKGROUND AND AIMS: Stratified therapy has entered clinical practice in primary biliary cholangitis (PBC), with routine use of second-line therapy in nonresponders to first-line therapy with ursodeoxycholic acid (UDCA). The mechanism for nonresponse to UDCA remains, however, unclear and we lack mechanistic serum markers. The UK-PBC study was established to explore the biological basis of UDCA nonresponse in PBC and identify markers to enhance treatment. APPROACH AND RESULTS: Discovery serum proteomics (Olink) with targeted multiplex validation were carried out in 526 subjects from the UK-PBC cohort and 97 healthy controls. In the discovery phase, untreated PBC patients (n = 68) exhibited an inflammatory proteome that is typically reduced in scale, but not resolved, with UDCA therapy (n = 416 treated patients). Nineteen proteins remained at a significant expression level (defined using stringent criteria) in UDCA-treated patients, six of them representing a tightly linked profile of chemokines (including CCL20, known to be released by biliary epithelial cells (BECs) undergoing senescence in PBC). All showed significant differential expression between UDCA responders and nonresponders in both the discovery and validation cohorts. A linear discriminant analysis, using serum levels of C-X-C motif chemokine ligand 11 and C-C motif chemokine ligand 20 as markers of responder status, indicated a high level of discrimination with an AUC of 0.91 (CI, 0.83-0.91). CONCLUSIONS: UDCA under-response in PBC is characterized by elevation of serum chemokines potentially related to cellular senescence and was previously shown to be released by BECs in PBC, suggesting a potential role in the pathogenesis of high-risk disease. These also have potential for development as biomarkers for identification of high-risk disease, and their clinical utility as biomarkers should be evaluated further in prospective studies.

Sleeve gastrectomy prevents hypertension associated with unique shifts in the gut microbiome.

INTRODUCTION: Bariatric surgery results in resolution of hypertension in over 50% of patients. While weight loss is a critical component to hypertension resolution after bariatric surgery, there may also be weight loss-independent mechanisms. OBJECTIVES: We hypothesized that sleeve gastrectomy (SG) initiates changes in the gut microbiome which reduce postoperative blood pressure. METHODS: Male, obese Zucker rats underwent SG, pair-fed sham, or ad-lib-fed sham surgery. Blood pressure measurements were performed 1 week pre-operatively, and at 2 and 6 weeks post-operatively. The stool microbiome composition was determined by 16S rDNA gene at 6 weeks post-operatively. Regression Random Forest modeling was performed to determine an association of the microbial composition with blood pressure. RESULTS: SG and pair-fed rats weighed significantly less than ad-lib-fed sham rats throughout the post-surgical period. At 6 weeks after surgery, SG rats had a significantly lower systolic blood pressure (149.2 ± 1.99 mmHg) than pair-fed (164.7 ± 7.87, p < 0.001) or ad-lib-fed sham rats (167.1 ± 2.41 mmHg, p < 0.001). There was a significant difference in multiple measures of beta diversity between SG rats and pair-fed and ad-lib-fed sham rats. 45.11% of the difference in blood pressure variability between samples was explained with the regression Random Forest model. CONCLUSION: SG in a rat model prevented hypertension progression independent of weight loss with changes in beta diversity and gut bacterial composition associated with the blood pressure outcome. These findings further support the metabolic efficacy of SG in treating hyperglycemia, cardiac dysfunction, and now hypertension, independent of obesity class.

Suppressor mutations reveal an NtrC-like response regulator, NmpR, for modulation of Type-IV Pili-dependent motility in Myxococcus xanthus.

Two-component signaling systems (TCS) regulate bacterial responses to environmental signals through the process of protein phosphorylation. Specifically, sensor histidine kinases (SK) recognize signals and propagate the response via phosphorylation of a cognate response regulator (RR) that functions to initiate transcription of specific genes. Signaling within a single TCS is remarkably specific and cross-talk between TCS is limited. However, regulation of the flow of information through complex signaling networks that include closely related TCS remains largely unknown. Additionally, many bacteria utilize multi-component signaling networks which provide additional genetic and biochemical interactions that must be regulated for signaling fidelity, input and output specificity, and phosphorylation kinetics. Here we describe the characterization of an NtrC-like RR that participates in regulation of Type-IV pilus-dependent motility of Myxococcus xanthus and is thus named NmpR, NtrC Modulator of Pili Regulator. A complex multi-component signaling system including NmpR was revealed by suppressor mutations that restored motility to cells lacking PilR, an evolutionarily conserved RR required for expression of pilA encoding the major Type-IV pilus monomer found in many bacterial species. The system contains at least four signaling proteins: a SK with a protoglobin sensor domain (NmpU), a hybrid SK (NmpS), a phospho-sink protein (NmpT), and an NtrC-like RR (NmpR). We demonstrate that ΔpilR bypass suppressor mutations affect regulation of the NmpRSTU multi-component system, such that NmpR activation is capable of restoring expression of pilA in the absence of PilR. Our findings indicate that pilus gene expression in M. xanthus is regulated by an extended network of TCS which interact to refine control of pilus function.

MiR-126-3p Is Dynamically Regulated in Endothelial-to-Mesenchymal Transition during Fibrosis.

In fibrotic diseases, myofibroblasts derive from a range of cell types including endothelial-to-mesenchymal transition (EndMT). Increasing evidence suggests that miRNAs are key regulators in biological processes but their profile is relatively understudied in EndMT. In human umbilical vein endothelial cells (HUVEC), EndMT was induced by treatment with TGFß2 and IL1ß. A significant decrease in endothelial markers such as VE-cadherin, CD31 and an increase in mesenchymal markers such as fibronectin were observed. In parallel, miRNA profiling showed that miR-126-3p was down-regulated in HUVECs undergoing EndMT and over-expression of miR-126-3p prevented EndMT, maintaining CD31 and repressing fibronectin expression. EndMT was investigated using lineage tracing with transgenic Cdh5-Cre-ERT2; Rosa26R-stop-YFP mice in two established models of fibrosis: cardiac ischaemic injury and kidney ureteric occlusion. In both cardiac and kidney fibrosis, lineage tracing showed a significant subpopulation of endothelial-derived cells expressed mesenchymal markers, indicating they had undergone EndMT. In addition, miR-126-3p was restricted to endothelial cells and down-regulated in murine fibrotic kidney and heart tissue. These findings were confirmed in patient kidney biopsies. MiR-126-3p expression is restricted to endothelial cells and is down-regulated during EndMT. Over-expression of miR-126-3p reduces EndMT, therefore, it could be considered for miRNA-based therapeutics in fibrotic organs.

Physiologic and biochemical rationale for treating COVID-19 patients with hyperbaric oxygen.

The SARS-Cov-2 (COVID-19) pandemic remains a major worldwide public health issue. Initially, improved supportive and anti-inflammatory intervention, often employing known drugs or technologies, provided measurable improvement in management. We have recently seen advances in specific therapeutic interventions and in vaccines. Nevertheless, it will be months before most of the world's population can be vaccinated to achieve herd immunity. In the interim, hyperbaric oxygen (HBO2) treatment offers several potentially beneficial therapeutic effects. Three small published series, one with a propensity-score-matched control group, have demonstrated safety and initial efficacy. Additional anecdotal reports are consistent with these publications. HBO2 delivers oxygen in extreme conditions of hypoxemia and tissue hypoxia, even in the presence of lung pathology. It provides anti-inflammatory and anti-proinflammatory effects likely to ameliorate the overexuberant immune response common to COVID-19. Unlike steroids, it exerts these effects without immune suppression. One study suggests HBO2 may reduce the hypercoagulability seen in COVID patients. Also, hyperbaric oxygen offers a likely successful intervention to address the oxygen debt expected to arise from a prolonged period of hypoxemia and tissue hypoxia. To date, 11 studies designed to investigate the impact of HBO2 on patients infected with SARS-Cov-2 have been posted on clinicaltrials.gov. This paper describes the promising physiologic and biochemical effects of hyperbaric oxygen in COVID-19 and potentially in other disorders with similar pathologic mechanisms.

Achromobacter xylosoxidans Cellular Pathology Is Correlated with Activation of a Type III Secretion System.

Achromobacter xylosoxidans is increasingly recognized as a colonizer of cystic fibrosis (CF) patients, but the role that A. xylosoxidans plays in pathology remains unknown. This knowledge gap is largely due to the lack of model systems available to study the toxic potential of this bacterium. Recently, a phospholipase A2 (PLA2) encoded by a majority of A. xylosoxidans genomes, termed AxoU, was identified. Here, we show that AxoU is a type III secretion system (T3SS) substrate that induces cytotoxicity to mammalian cells. A tissue culture model was developed showing that a subset of A. xylosoxidans isolates from CF patients induce cytotoxicity in macrophages, suggestive of a pathogenic or inflammatory role in the CF lung. In a toxic strain, cytotoxicity is correlated with transcriptional activation of axoU and T3SS genes, demonstrating that this model can be used as a tool to identify and track expression of virulence determinants produced by this poorly understood bacterium.

Examining the neural and cognitive processes that underlie reading through naming speed tasks.

We combined fMRI with eye tracking and speech recording to examine the neural and cognitive mechanisms that underlie reading. To simplify the study of the complex processes involved during reading, we used naming speed (NS) tasks (also known as rapid automatized naming or RAN) as a focus for this study, in which average reading right-handed adults named sets of stimuli (letters or objects) as quickly and accurately as possible. Due to the possibility of spoken output during fMRI studies creating motion artifacts, we employed both an overt session and a covert session. When comparing the two sessions, there were no significant differences in behavioral performance, sensorimotor activation (except for regions involved in the motor aspects of speech production) or activation in regions within the left-hemisphere-dominant neural reading network. This established that differences found between the tasks within the reading network were not attributed to speech production motion artifacts or sensorimotor processes. Both behavioral and neuroimaging measures showed that letter naming was a more automatic and efficient task than object naming. Furthermore, specific manipulations to the NS tasks to make the stimuli more visually and/or phonologically similar differentially activated the reading network in the left hemisphere associated with phonological, orthographic and orthographic-to-phonological processing, but not articulatory/motor processing related to speech production. These findings further our understanding of the underlying neural processes that support reading by examining how activation within the reading network differs with both task performance and task characteristics.

A C-terminal CXCL8 peptide based on chemokine-glycosaminoglycan interactions reduces neutrophil adhesion and migration during inflammation.

Leucocyte recruitment is critical during many acute and chronic inflammatory diseases. Chemokines are key mediators of leucocyte recruitment during the inflammatory response, by signalling through specific chemokine G-protein-coupled receptors (GPCRs). In addition, chemokines interact with cell-surface glycosaminoglycans (GAGs) to generate a chemotactic gradient. The chemokine interleukin-8/CXCL8, a prototypical neutrophil chemoattractant, is characterized by a long, highly positively charged GAG-binding C-terminal region, absent in most other chemokines. To examine whether the CXCL8 C-terminal peptide has a modulatory role in GAG binding during neutrophil recruitment, we synthesized the wild-type CXCL8 C-terminal [CXCL8 (54-72)] (Peptide 1), a peptide with a substitution of glutamic acid (E) 70 with lysine (K) (Peptide 2) to increase positive charge; and also, a scrambled sequence peptide (Peptide 3). Surface plasmon resonance showed that Peptide 1, corresponding to the core CXCL8 GAG-binding region, binds to GAG but Peptide 2 binding was detected at lower concentrations. In the absence of cellular GAG, the peptides did not affect CXCL8-induced calcium signalling or neutrophil chemotaxis along a diffusion gradient, suggesting no effect on GPCR binding. All peptides equally inhibited neutrophil adhesion to endothelial cells under physiological flow conditions. Peptide 2, with its greater positive charge and binding to polyanionic GAG, inhibited CXCL8-induced neutrophil transendothelial migration. Our studies suggest that the E70K CXCL8 peptide, may serve as a lead molecule for further development of therapeutic inhibitors of neutrophil-mediated inflammation based on modulation of chemokine-GAG binding.