Decision-level data fusion based on laser-induced breakdown and Raman spectroscopy: A study of bimodal spectroscopy for diagnosis of lung cancer at different stages.

Lung cancer staging is crucial for personalized treatment and improved prognosis. We propose a novel bimodal diagnostic approach that integrates LIBS and Raman technologies into a single platform, enabling comprehensive tissue elemental and molecular analysis. This strategy identifies critical staging elements and molecular marker signatures of lung tumors. LIBS detects concentration patterns of elemental lines including Mg (I), Mg (II), Ca (I), Ca (II), Fe (I), and Cu (II). Concurrently, Raman spectroscopy identifies changes in molecular content, such as phenylalanine (1033 cm-1), tyrosine (1174 cm-1), tryptophan (1207 cm-1), amide III (1267 cm-1), and proteins (1126 cm-1 and 1447 cm-1), among others. The bimodal information is fused using a decision-level Bayesian fusion model, significantly enhancing the performance of the convolutional neural network architecture in classification algorithms, with an accuracy of 99.17 %, sensitivity of 99.17 %, and specificity of 99.88 %. This study provides a powerful new tool for the accurate staging and diagnosis of lung tumors.

Investigating the mechanistic impact of pork soft tissue preparation techniques on the classification precision of laser-induced breakdown spectroscopy.

The investigation of the mechanism underlying the impact of biological soft tissue sample preparation methods on laser-induced breakdown spectroscopy (LIBS) signals can enhance the stability of LIBS signals. Our study focused on four specific preparation methods applied to pork samples: rapid freezing, fresh slicing, drying, and pressing. The influence of various preparation techniques on the signal-to-noise ratio and fluctuation of Ca, Na, Mg, and CN bands within the sample spectra was assessed. The signal-to-noise ratios for samples that were dried and pressed notably improved. And the pressing method effectively mitigated the uneven distribution of pork tissue components, displaying superior spectral line stability. To explain this phenomenon, we used the Saha-Boltzmann diagram to estimate the plasma temperature. Remarkably, there was a significant reduction in plasma temperature fluctuations across four pressed samples, with a standard deviation of 108.53. Furthermore, we undertook a classification analysis employing support vector machine models to corroborate the generalization efficacy of the sample preparation technique. Dried and pressed samples demonstrated notably higher classification accuracy, precision, and recall (all >93%) compared to frozen and fresh samples, where these metrics remained below 86%. The performance of the SVM model was ultimately evaluated using Receiver Operating Characteristic (ROC) curves and the Area Under the Curve (AUC). The AUC for the frozen, fresh, dried, and pressed samples was 0.854, 0.907, 0.989, and 0.996, respectively. The findings revealed that the pressing method exhibited superior performance, followed by drying, fresh slicing, and freezing, in descending order of effectiveness.

Research on a new multiple-screening method for laser-induced plasma spectroscopy utilizing Lorentz.

In the field of Laser Induced Breakdown Spectroscopy (LIBS) research, the screening and extraction of complex spectra play a crucial role in enhancing the accuracy of quantitative analysis. This paper introduces a novel approach for multiple screenings of LIBS spectra using Lorentz Screening and Sensitivity and Volatility Analysis. Initially, Create symmetrical sampling standards for Lorentz fitting. Then the Lorentz fitting is used to uniformly screen the collected spectral information on both sides in order to eliminate adjacent interference peaks. Subsequently, Sensitivity and Volatility Analysis is employed to further remove overlapping peaks and select spectra with low volatility and high sensitivity. Sensitivity and Volatility Analysis is a spectral discrimination method proposed on the premise of intensity's correlation with concentration. It utilizes a Z-score method that incorporates both deviation and standard deviation for effective analysis. Furthermore, it meticulously selects spectral lines with minimal interference and volatility, thereby augmenting the precision of quantitative analysis. The quantitative accuracy (R2) for Chromium (Cr) and Nickel (Ni) elements can reach 0.9919 and 0.9768, respectively. Their average errors can be reduced to 0.0566 % and 0.1024 %. The study demonstrates that Lorentz Screening and Sensitivity and Volatility Analysis can select high-quality characteristic spectral lines to improve the performance of the model.

Time-resolved RNA-seq analysis to unravel the in vivo competence induction by Streptococcus pneumoniae during pneumonia-derived sepsis.

Competence development in Streptococcus pneumoniae (pneumococcus) is tightly intertwined with virulence. In addition to genes encoding genetic transformation machinery, the competence regulon also regulates the expression of allolytic factors, bacteriocins, and cytotoxins. Pneumococcal competence system has been extensively interrogated in vitro where the short transient competent state upregulates the expression of three distinct phases of "early," "late," and "delayed" genes. Recently, we have demonstrated that the pneumococcal competent state develops naturally in mouse models of pneumonia-derived sepsis. To unravel the underlying adaptive mechanisms driving the development of the competent state, we conducted a time-resolved transcriptomic analysis guided by the spatiotemporal live in vivo imaging system of competence induction during pneumonia-derived sepsis. Mouse lungs infected by the serotype 2 strain D39 expressing a competent state-specific reporter gene (D39-ssbB-luc) were subjected to RNA sequencing guided by monitoring the competence development at 0, 12, 24, and, at the moribund state, >40 hours post-infection (hpi). Transcriptomic analysis revealed that the competence-specific gene expression patterns in vivo were distinct from those under in vitro conditions. There was significant upregulation of early, late, and some delayed phase competence-specific genes as early as 12 hpi, suggesting that the pneumococcal competence regulon is important for adaptation to the lung environment. Additionally, members of the histidine triad (pht) gene family were sharply upregulated at 12 hpi followed by a steep decline throughout the rest of the infection cycle, suggesting that Pht proteins participate in the early adaptation to the lung environment. Further analysis revealed that Pht proteins execute a metal ion-dependent regulatory role in competence induction.IMPORTANCEThe induction of pneumococcal competence for genetic transformation has been extensively studied in vitro but poorly understood during lung infection. We utilized a combination of live imaging and RNA sequencing to monitor the development of a competent state during acute pneumonia. Upregulation of competence-specific genes was observed as early as 12 hour post-infection, suggesting that the pneumococcal competence regulon plays an important role in adapting pneumococcus to the stressful lung environment. Among others, we report novel finding that the pneumococcal histidine triad (pht) family of genes participates in the adaptation to the lung environment and regulates pneumococcal competence induction.

Fusion of laser-induced breakdown spectroscopy technology and deep learning: a new method to identify malignant and benign lung tumors with high accuracy.

Precisely distinguishing between malignant and benign lung tumors is pivotal for suggesting therapeutic strategies and enhancing prognosis, yet this differentiation remains a daunting task. The growth rates, metastatic potentials, and prognoses of benign and malignant tumors differ significantly. Developing specialized treatment protocols tailored to various tumor types is essential for enhancing patient survival outcomes. Employing laser-induced breakdown spectroscopy (LIBS) in conjunction with a deep learning methodology, we attained a high-precision differential diagnosis of malignant and benign lung tumors. First, LIBS spectra of malignant tumors, benign tumors, and normal tissues were collected. The spectra were preprocessed and Z score normalized. Then, the intensities of the Mg II 279.6, Mg I 285.2, Ca II 393.4, Cu II 518.3, and Na I 589.6 nm lines were analyzed in the spectra of the three tissues. The analytical results show that the elemental lines have different contents in the three tissues and can be used as a basis for distinguishing between the three tissues. Finally, the RF-1D ResNet model was constructed by combining the feature importance assessment method of random forest (RF) and one-dimensional residual network (1D ResNet). The classification accuracy, precision, sensitivity, and specificity of the RF-1D ResNet model were 91.1%, 91.6%, 91.3%, and 91.3%, respectively. And the model demonstrates superior performance with an area under the curve (AUC) value of 0.99. The above results show that combining LIBS with deep learning is an effective way to diagnose malignant and benign tumors.

A study of the spectral signal effect of self-holes in metal additive manufacturing components using laser-induced breakdown spectroscopy (LIBS).

Understanding the detection mechanism of hole defects in metal additive manufacturing (AM) components is of great significance for the detection of metal AM component defects using laser-induced breakdown spectroscopy (LIBS). In this work, the mapping relationship between the hole defects of metal AM components and the LIBS spectral signal was studied using the controlled variable method. The effect of hole defects mostly showed a suppression effect and peaked at a hole depth of 1.0 mm when the LIBS system was at its optimal excitation parameter. To explore the possible reasons behind the inhibitory effect of self-holes, the variation law of the plasma temperature with and without hole defects was further investigated. Our results showed that the plasma temperature change curve was similar to the spectral line intensity change trend. Finally, the linear relationship between the focal length effect and the hole effect, and the relationship between the constraint effect and the hole effect were studied. The minimum fitting R2 between the constraint effect and the hole effect was 0.979. We believed that the inhibition of the hole effect was mainly caused by the absorption and loss of energy in the plasma during the process of plasma radiation and shock wave reflection from the hole wall. By studying the detection mechanism of hole defects in metal additive manufacturing components excited by LIBS and finding the effective characteristics of hole defects in metal AM components, it is helpful to achieve higher precision and higher sensitivity defect detection.

Simultaneous co-Photocatalytic CO2 Reduction and Ethanol Oxidation towards Synergistic Acetaldehyde Synthesis.

Photocatalytic conversion of CO2 is of great interest but it often suffers sluggish oxidation half reaction and undesired by-products. Here, we report for the first the simultaneous co-photocatalytic CO2 reduction and ethanol oxidation towards one identical value-added CH3 CHO product on a rubidium and potassium co-modified carbon nitride (CN-KRb). The CN-KRb offers a record photocatalytic activity of 1212.3 µmol h-1 g-1 with a high selectivity of 93.3 % for CH3 CHO production, outperforming all the state-of-art CO2 photocatalysts. It is disclosed that the introduced Rb boosts the *OHCCHO fromation and facilitates the CH3 CHO desorption, while K promotes ethanol adsorption and activation. Moreover, the H+ stemming from ethanol oxidation is confirmed to participate in the CO2 reduction process, endowing near ideal overall atomic economy. This work provides a new strategy for effective use of the photoexcited electron and hole for high selective and sustainable conversion of CO2 paired with oxidation reaction into identical product.

A Review of Processes for Removing Antibiotics from Breeding Wastewater.

Antibiotic pollution has become an increasingly serious issue due to the extensive application of antibiotics, their resistance to removal, and the harmful effects on aquatic environments and humans. Breeding wastewater is one of the most important sources of antibiotics in the aquatic environment because of the undeveloped treatment systems in breeding farms. It is imperative to establish an effective antibiotic removal process for breeding wastewater. This paper reviews the treatment methods used to remove antibiotics from breeding wastewater. The mechanisms and removal efficiency of constructed wetlands, biological treatments, advanced oxidation processes (AOPs), membrane technology, and combined treatments are explained in detail, and the advantages and disadvantages of the various treatment methods are compared and analyzed. Constructed wetlands have high removal rates for sulfonamide (SM), tetracycline (TC), and quinolone (QN). The antibiotic removal efficiency of biological treatment methods is affected by various processes and environmental factors, whereas AOPs and combined treatment methods have better antibiotic removal effects. Although it has broad application prospects, the application of membrane technology for the treatment of antibiotics in breeding wastewater needs further research.

Random Peptide Mixtures as Safe and Effective Antimicrobials against Pseudomonas aeruginosa and MRSA in Mouse Models of Bacteremia and Pneumonia.

Antibiotic resistance is a daunting challenge in modern medicine, and novel approaches that minimize the emergence of resistant pathogens are desperately needed. Antimicrobial peptides are newer therapeutics that attempt to do this; however, they fall short because of low to moderate antimicrobial activity, low protease stability, susceptibility to resistance development, and high cost of production. The recently developed random peptide mixtures (RPMs) are promising alternatives. RPMs are synthesized by incorporating a defined proportion of two amino acids at each coupling step rather than just one, making them highly variable but still defined in their overall composition, chain length, and stereochemistry. Because RPMs have extreme diversity, it is unlikely that bacteria would be capable of rapidly evolving resistance. However, their efficacy against pathogens in animal models of human infectious diseases remained uncharacterized. Here, we demonstrated that RPMs have strong safety and pharmacokinetic profiles. RPMs rapidly killed both Pseudomonas aeruginosa and Staphylococcus aureus efficiently and disrupted preformed biofilms by both pathogens. Importantly, RPMs were efficacious against both pathogens in mouse models of bacteremia and acute pneumonia. Our results demonstrate that RPMs are potent broad-spectrum therapeutics against antibiotic-resistant pathogens.

Immunoregulatory and Antimicrobial Activity of Bovine Neutrophil ß-Defensin-5-Loaded PLGA Nanoparticles against Mycobacterium bovis.

Mycobacterium bovis (M. bovis) is a member of the Mycobacterium tuberculosis complex imposing a high zoonotic threat to human health. The limited efficacy of BCG (Bacillus Calmette-Guérin) and upsurges of drug-resistant tuberculosis require new effective vaccination approaches and anti-TB drugs. Poly (lactic-co-glycolic acid) (PLGA) is a preferential drug delivery system candidate. In this study, we formulated PLGA nanoparticles (NPs) encapsulating the recombinant protein bovine neutrophil ß-defensin-5 (B5), and investigated its role in immunomodulation and antimicrobial activity against M. bovis challenge. Using the classical water-oil-water solvent-evaporation method, B5-NPs were prepared, with encapsulation efficiency of 85.5% ± 2.5%. These spherical NPs were 206.6 ± 26.6 nm in diameter, with a negatively charged surface (ζ-potential -27.1 ± 1.5 mV). The encapsulated B5 protein from B5-NPs was released slowly under physiological conditions. B5 or B5-NPs efficiently enhanced the secretion of tumor necrosis factor α (TNF-α), interleukin (IL)-1ß and IL-10 in J774A.1 macrophages. B5-NPs-immunized mice showed significant increases in the production of TNF-α and immunoglobulin A (IgA) in serum, and the proportion of CD4+ T cells in spleen compared with B5 alone. In immunoprotection studies, B5-NPs-immunized mice displayed significant reductions in pulmonary inflammatory area, bacterial burden in the lungs and spleen at 4-week after M. bovis challenge. In treatment studies, B5, but not B5-NPs, assisted rifampicin (RIF) with inhibition of bacterial replication in the lungs and spleen. Moreover, B5 alone also significantly reduced the bacterial load in the lungs and spleen. Altogether, our findings highlight the significance of the B5-PLGA NPs in terms of promoting the immune effect of BCG and the B5 in enhancing the therapeutic effect of RIF against M. bovis.

A comparative study on phenazone degradation by sulfate radicals based processes.

In this paper, a comparative study on removal of the emerging pollutant phenazone (PNZ) by two treatment processes UVA/Fe(II)/persulfate (PS) and UVA/Fe(II)/peroxymonosulfate (PMS) was conducted. The two processes showed high efficiency in PNZ degradation, followed by a reasonable mineralization. The treatment system with PMS was found to be more efficient for PNZ degradation than that with PS due to the larger amounts of radicals generated. While the treatment process UVA/Fe(II)/PS showed higher ΔTOC/ΔSMX (TOC removal per unit of PNZ decay) than UVA/Fe(II)/PMS process. The sulfate and hydroxyl radicals played dominant roles in PNZ degradation in the UVA/Fe(II)/PS and UVA/Fe(II)/PMS process, respectively. Six and seven intermediates during PNZ degradation by UVA/Fe(II)/PS and UVA/Fe(II)/PMS process were detected, respectively. Among the detected intermediates, six of them are found for the first time. It takes shorter time for toxicity elimination by UVA/Fe(II)/PS process than UVA/Fe(II)/PMS, possibly due to the lower Kow values of hydroxylated products. The results demonstrate that UVA/Fe(II)/PMS process is more efficient in PNZ degradation, while UVA/Fe(II)/PS is more efficient in detoxification of PNZ. The two sulfate radicals based processes have good potentials in degradation, mineralization and detoxification of the emerging contaminants such as PNZ.

Surfactant phospholipids act as molecular switches for premature induction of quorum sensing-dependent virulence in Pseudomonas aeruginosa.

The virulence behaviors of many Gram-negative bacterial pathogens are governed by quorum-sensing (QS), a hierarchical system of gene regulation that relies on population density by producing and detecting extracellular signaling molecules. Although extensively studied under in vitro conditions, adaptation of QS system to physiologically relevant host environment is not fully understood. In this study, we investigated the influence of lung environment on the regulation of Pseudomonas aeruginosa virulence factors by QS in a mouse model of acute pneumonia. When cultured under laboratory conditions in lysogeny broth, wild-type P. aeruginosa strain PAO1 began to express QS-regulated virulence factors elastase B (LasB) and rhamnolipids (RhlA) during transition from late-exponential into stationary growth phase. In contrast, during acute pneumonia as well as when cultured in mouse bronchial alveolar lavage fluids (BALF), exponential phase PAO1 bacteria at low population density prematurely expressed QS regulatory genes lasI-lasR and rhlI-rhlR and their downstream virulence genes lasB and rhlA. Further analysis indicated that surfactant phospholipids were the primary components within BALF that induced the synthesis of N-(3-oxododecanoyl)-L-homoserine lactone (C12-HSL), which triggered premature expression of LasB and RhlA. Both phenol extraction and phospholipase A2 digestion abolished the ability of mouse BALF to promote LasB and RhlA expression. In contrast, provision of the major surfactant phospholipid dipalmitoylphosphatidylcholine (DPPC) restored the expression of both virulence factors. Collectively, our study demonstrates P. aeruginosa modulates its QS to coordinate the expression of virulence factors during acute pneumonia by recognizing pulmonary surfactant phospholipids.

Exendin-4 restores airway mucus homeostasis through the GLP1R-PKA-PPARγ-FOXA2-phosphatase signaling.

Goblet cell hyperplasia and metaplasia and excessive mucus are prominent pathologies of chronic airway diseases such as chronic obstructive pulmonary disease (COPD), cystic fibrosis (CF), and chronic bronchitis. Chronic infection by respiratory pathogens, including Pseudomonas aeruginosa, exacerbates cyclical proinflammatory responses and mucus hypersecretion. P. aeruginosa and its virulence factor pyocyanin contribute to these pathologies by inhibiting FOXA2, a key transcriptional regulator of mucus homeostasis, through activation of antagonistic signaling pathways EGFR-AKT/ERK1/2 and IL-4/IL-13-STAT6-SPDEF. However, FOXA2-targeted therapy has not been previously explored. Here, we examined the feasibility of repurposing the incretin mimetic Exendin-4 to restore FOXA2-mediated airway mucus homeostasis. We have found that Exendin-4 restored FOXA2 expression, attenuated mucin production in COPD and CF-diseased airway cells, and reduced mucin and P. aeruginosa burden in mouse lungs. Mechanistically, Exendin-4 activated the GLP1R-PKA-PPAR-γ-dependent phosphatases PTEN and PTP1B, which inhibited key kinases within both EGFR and STAT6 signaling cascades. Our results may lead to the repurposing of Exendin-4 and other incretin mimetics to restore FOXA2 function and ultimately regulate excessive mucus in diseased airways.

Streptococcus pneumoniae Elaborates Persistent and Prolonged Competent State during Pneumonia-Derived Sepsis.

The competence regulon of pneumococcus regulates both genetic transformation and virulence. However, competence induction during host infection has not been examined. By using the serotype 2 strain D39, we transcriptionally fused the firefly luciferase (luc) to competence-specific genes and spatiotemporally monitored the competence development in a mouse model of pneumonia-derived sepsis. In contrast to the universally reported short transient burst of competent state in vitro, the naturally developed competent state was prolonged and persistent during pneumonia-derived sepsis. The competent state began at approximately 20 h postinfection (hpi) and facilitated systemic invasion and sepsis development and progressed in different manners. In some mice, acute pneumonia quickly led to sepsis and death, accompanied by increasing intensity of the competence signal. In the remaining mice, pneumonia lasted longer, with the competence signal decreasing at first but increasing as the infection became septic. The concentration of pneumococcal inoculum (1 × 106 to 1 × 108 CFU/mouse) and postinfection lung bacterial burden did not appreciably impact the kinetics of competence induction. Exogenously provided competence stimulating peptide 1 (CSP1) failed to modulate the onset kinetics of competence development in vivo The competence shutoff regulator DprA was highly expressed during pneumonia-derived sepsis but failed to turn off the competent state in mice. Competent D39 bacteria propagated the competence signal through cell-to-cell contact rather than the classically described quorum-sensing mechanism. Finally, clinical pneumococcal strains of different serotypes were also able to develop natural competence during pneumonia-derived sepsis.

Designing cyclic competence-stimulating peptide (CSP) analogs with pan-group quorum-sensing inhibition activity in Streptococcus pneumoniae.

Streptococcus pneumoniae is an opportunistic human pathogen that utilizes the competence regulon, a quorum-sensing circuitry, to acquire antibiotic resistance genes and initiate its attack on the human host. Interception of the competence regulon can therefore be utilized to study S. pneumoniae cell-cell communication and behavioral changes, as well as attenuate S. pneumoniae infectivity. Herein we report the design and synthesis of cyclic dominant negative competence-stimulating peptide (dnCSP) analogs capable of intercepting the competence regulon in both S. pneumoniae specificity groups with activities at the low nanomolar range. Structural analysis of lead analogs provided important insights as to the molecular mechanism that drives CSP receptor binding and revealed that the pan-group cyclic CSPs exhibit a chimeric hydrophobic patch conformation that resembles the hydrophobic patches required for both ComD1 and ComD2 binding. Moreover, the lead cyclic dnCSP, CSP1-E1A-cyc(Dap6E10), was found to possess superior pharmacological properties, including improved resistance to enzymatic degradation, while remaining nontoxic. Lastly, CSP1-E1A-cyc(Dap6E10) was capable of attenuating mouse mortality during acute pneumonia caused by both group 1 and group 2 S. pneumoniae strains. This cyclic pan-group dnCSP is therefore a promising drug lead scaffold against S. pneumoniae infections that could be administered individually or utilized in combination therapy to augment the effects of current antimicrobial agents.

Cooperation of Fe(II) and peroxymonosulfate for enhancement of sulfamethoxazole photodegradation: mechanism study and toxicity elimination.

This study aims at systematically examining the potential of removing the emerging pollutant sulfamethoxazole (SMX) from aqueous solution under photo-assisted peroxymonosulfate (PMS) activation by Fe(ii). The residual SMX was determined by HPLC analysis. The concentration of Fe(ii) ([Fe(ii)]) was monitored during SMX degradation. Fe(ii) and PMS cooperated with each other for faster SMX photodegradation; a relatively lower or higher molar ratio between Fe(ii) and PMS led to lower SMX removal efficiency due to the insufficient radicals or scavenging effect. A fixed reaction ratio of [Fe(ii)]Δ : [PMS]0 with 1.6 : 1 at the first 5 min was detected for reactions with [Fe(ii)]0 ≥ 0.5 mM or [PMS]0 ≤ 0.25 mM. The pH level of around 6.0 was recommended for optimal SMX removal under the treatment process UVA + Fe(ii) + PMS. Six transformation products were detected through UPLC/ESI-MS analysis, and four of the proposed intermediates were newly reported. Concentrations of the intermediates were proposed based on the isoxazole-ring balance and the Beer-Lambert law. Total Organic Carbon (TOC) reduction was mainly attributed to the loss of benzene ring, N-S cleavage, and isoxazole ring opening during SMX degradation. The contributions of reactive species OH˙ and SO4˙- were determined based on quench tests. The acute toxicity of SMX to the rotifers was eliminated after the proposed treatment, demonstrating that the process was effective for SMX treatment and safe to the environment.

DprA-Dependent Exit from the Competent State Regulates Multifaceted Streptococcus pneumoniae Virulence.

Streptococcus pneumoniae (pneumococcus) causes multiple infectious diseases. The pneumococcal competence system facilitates genetic transformation, spreads antibiotic resistance, and contributes to virulence. DNA-processing protein A (DprA) regulates the exit of pneumococcus from the competent state. Previously, we have shown that DprA is important in both bacteremia and pneumonia infections. Here, we examined the mechanisms of virulence attenuation in a ΔdprA mutant. Compared to the parental wild-type D39, the ΔdprA mutant enters the competent state when exposed to lower concentrations of the competence-stimulating peptide CSP1. The ΔdprA mutant overexpresses ComM, which delays cell separation after division. Additionally, the ΔdprA mutant overexpresses allolytic factors LytA, CbpD, and CibAB and is more susceptible to detergent-triggered lysis. Disabling of the competent-state-specific induction of ComM and allolytic factors compensated for the virulence loss in the ΔdprA mutant, suggesting that overexpression of these factors contributes to virulence attenuation. Finally, the ΔdprA mutant fails to downregulate the expression of multiple competence-regulated genes, leading to the excessive energy consumption. Collectively, these results indicate that an inability to properly exit the competent state disrupts multiple cellular processes that cause virulence attenuation in the ΔdprA mutant.

FOXA2 depletion leads to mucus hypersecretion in canine airways with respiratory diseases.

Because of exposure to environmental pollutants, infectious agents, and genetic predisposition, companion animals develop respiratory illnesses similar to those in humans. Older dogs of smaller breeds develop canine infectious respiratory disease, chronic bronchitis, and chronic obstructive pulmonary disease, with chronic lung infection, airway goblet cell hyperplasia and metaplasia, and mucus hypersecretion. Excessive mucus clogs airways, reduces gas exchanges, disables the mucociliary clearance, and reduces drug penetration. The Forkhead box protein A2 (FOXA2) is a key transcriptional regulator that maintains airway mucus homeostasis. Prior studies have shown that FOXA2 expression is frequently depleted in diseased human airways. Unfortunately, FOXA2 depletion has not been examined in dogs. Our current study indicated that both single bacterial infection by Pseudomonas aeruginosa and Bordetella bronchiseptica and polymicrobial infection by viral/bacterial pathogens depleted FOXA2 in canine airways, resulting in goblet cell hyperplasia and metaplasia and excessive mucus production. Furthermore, P. aeruginosa virulence factor pyocyanin activated the antagonistic STAT6 and epidermal growth factor receptor signalling pathways to inhibit FOXA2. Unravelling the mechanism of FOXA2 inactivation will hasten the development of non-antibiotic therapeutics to improve mucociliary clearance of pathogens in canine airway.

Development of a Dominant Negative Competence-Stimulating Peptide (dnCSP) that Attenuates Streptococcus pneumoniae Infectivity in a Mouse Model of Acute Pneumonia.

Streptococcus pneumoniae (pneumococcus) is a prevalent human pathogen responsible for a variety of diseases, including pneumonia, bacteremia, sepsis, meningitis and otitis media, with a death toll of >22 000 a year in the United States alone. Pneumococcus uses the competence regulon and its associated signaling peptide, the competence stimulating peptide (CSP), to initiate its attack on the host and establish an infection. In this work, we set out to: 1) develop a pan-group quorum sensing inhibitor that could effectively interact with both the pneumococcus ComD1 and ComD2 receptors; and 2) evaluate the utility of dominant-negative CSPs (dnCSPs) in attenuating pneumococcus infectivity. Our results highlight the potential of inhibiting the competence regulon as a therapeutic approach to combat pneumococcus infections.

Pseudomonas aeruginosa pyocyanin modulates mucin glycosylation with sialyl-Lewis(x) to increase binding to airway epithelial cells.

Cystic fibrosis (CF) patients battle life-long pulmonary infections with the respiratory pathogen Pseudomonas aeruginosa (PA). An overabundance of mucus in CF airways provides a favorable niche for PA growth. When compared with that of non-CF individuals, mucus of CF airways is enriched in sialyl-Lewis(x), a preferred binding receptor for PA. Notably, the levels of sialyl-Lewis(x) directly correlate with infection severity in CF patients. However, the mechanism by which PA causes increased sialylation remains uncharacterized. In this study, we examined the ability of PA virulence factors to modulate sialyl-Lewis(x) modification in airway mucins. We found pyocyanin (PCN) to be a potent inducer of sialyl-Lewis(x) in both mouse airways and in primary and immortalized CF and non-CF human airway epithelial cells. PCN increased the expression of C2/4GnT and ST3Gal-IV, two of the glycosyltransferases responsible for the stepwise biosynthesis of sialyl-Lewis(x), through a tumor necrosis factor (TNF)-α-mediated phosphoinositol-specific phospholipase C (PI-PLC)-dependent pathway. Furthermore, PA bound more efficiently to airway epithelial cells pre-exposed to PCN in a flagellar cap-dependent manner. Importantly, antibodies against sialyl-Lewis(x) and anti-TNF-α attenuated PA binding. These results indicate that PA secretes PCN to induce a favorable environment for chronic colonization of CF lungs by increasing the glycosylation of airway mucins with sialyl-Lewis(x).