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The statistical validation of peptide and protein identifications in mass spectrometry proteomics is a critical step in the analytical workflow. This is particularly important in discovery experiments to ensure only confident identifications are accumulated for downstream analysis and biomarker consideration. However, the inherent nature of discovery proteomics experiments leads to scenarios where the search space will inflate substantially due to the increased number of potential proteins that are being queried in each sample. In these cases, issues will begin to arise when the machine learning algorithms that are trained on an experiment specific basis cannot accurately distinguish between correct and incorrect identifications and will struggle to accurately control the false discovery rate. Here, we propose an alternative validation algorithm trained on a curated external data set of 2.8 million extracted peakgroups that leverages advanced machine learning techniques to create a generalizable peakgroup scoring (GPS) method for data independent acquisition (DIA) mass spectrometry. By breaking the reliance on the experimental data at hand and instead training on a curated external dataset, GPS can confidently control the false discovery rate while increasing the number of identifications and providing more accurate quantification in different search space scenarios. To first test the performance of GPS in a standard experimental environment and to provide a benchmark against other methods, a novel spike-in data set with known varying concentrations was analyzed. When compared to existing methods GPS increased the nunmber of identifications by 5-18% and was able to provide more accurate quantification by increasing the number of ratio validated identifications by 24-74%. To evaluate GPS in a larger search space, a novel data set of 141 blood plasma samples from patients developing acute kidney injury after sepsis was searched with a human tissue spectral library (10000+ proteins). Using GPS, we were able to provide a 207-377% increase in the number of candidate differentially abundant proteins compared to the existing methods while maintaining competitive numbers of global identifications. Finally, using an optimized human tissue library and workflow we were able to identify 1205 proteins from the 141 plasma samples and increase the number of candidate differentially abundant proteins by 70.87%. With the addition of machine learning aided differential expression, we were able to identify potential new biomarkers for stratifying subphenotypes of acute kidney injury in sepsis. These findings suggest that by using a generalized model such as GPS in tandem with a massive scale spectral library it is possible to expand the boundaries of discovery experiments in DIA proteomics. GPS is open source and freely available on github at (https://github.com/InfectionMedicineProteomics/gscore).

Sepsis is the major cause of mortality across intensive care units globally, yet details of accompanying pathological molecular events remains unclear. This knowledge gap has resulted in ineffective development of sepsis-specific biomarkers and therapies, and suboptimal treatment regimens to prevent or reverse organ damage. Here, we used pharmacoproteomics to score treatment effects in a murine Escherichia coli sepsis model based on changes in the organ, cell, and plasma proteome landscapes. A combination of pathophysiological read-outs and time-resolved proteome maps of organs and blood enabled us to define time-dependent and organotypic proteotypes of dysfunction and damage upon administration of several combinations of the broad-spectrum beta-lactam antibiotic meropenem (Mem) and/or the immunomodulatory glucocorticoid methylprednisolone (Gcc). Three distinct response patterns were identified, defined as intervention-specific reversions, non-reversions, and specific intervention-induced effects, which depended on the underlying proteotype and varied significantly across organs. In the later stages of the disease, Gcc enhanced some positive treatment effects of Mem with superior reduction of the inflammatory response in the kidneys and partial restoration of sepsis-induced metabolic dysfunction. Unexpectedly, Mem introduced sepsis-independent perturbations in the mitochondrial proteome that were to some degree counteracted by Gcc. In summary, this study provides a pharmacoproteomic resource describing the time-resolved septic organ failure landscape across organs and blood, coupled to a novel scoring strategy that captures unintended secondary drug effects as an important criterion to consider when assessing therapeutic efficacy. Such information is critical for quantitative, objective, and organotypic assessment of benefits and unintended effects of candidate treatments in relationship to dosing, timing, and potential synergistic combinations in murine sepsis models.

Interstitial lung diseases such as idiopathic pulmonary fibrosis (IPF) are caused by persistent micro-injuries to alveolar epithelial tissues accompanied by aberrant repair processes. Despite substantial advancement in our understanding of IPF progression, numerous questions remain concerning disease pathology. IPF is currently treated with pirfenidone and nintedanib, compounds which slow the rate of disease progression but fail to target underlying pathophysiological mechanisms. The DNA repair enzyme 8-oxoguanine DNA glycosylase-1 (OGG1) is upregulated following TGF-β1 exposure in several fibrosis-associated cell types. Currently, no pharmaceutical solutions targeting OGG1 have been utilized in the treatment of IPF. In this study, administration of Ogg1-targetting siRNA, mitigated bleomycin-induced pulmonary fibrosis in mice, thereby highlighting OGG1 as a tractable target in lung fibrosis. The novel small molecule OGG1 inhibitor, TH5487, decreased myofibroblast transition and associated pro-fibrotic markers in fibroblast cells. In addition, TH5487 decreased pro-inflammatory cytokine production, inflammatory cell infiltration, and lung remodeling in a murine model of bleomycin-induced pulmonary fibrosis. OGG1 and SMAD7 interact to induce fibroblast proliferation and differentiation, with both increased in fibrotic murine and IPF patient lung tissue. Taken together, these data strongly suggest that TH5487 is a potent, specific, and clinically-relevant treatment for IPF.

Transrectal prostate biopsy (TRbx) transfers colonic bacteria into prostatic tissue, potentially causing infectious complications, including sepsis. Our objective was to determine whether biopsy needle shape, surface properties and sampling mechanism affect the number of bacteria transferred through the colon wall, and evaluate a novel needle with improved properties.The standard Tru-Cut biopsy needle used today was evaluated for mechanisms of bacterial transfer in a pilot study. A novel Tru-Cut needle (Forsvall needle prototype) was developed. TRbx was simulated using human colons ex-vivo. Four subtypes of the prototype needle were compared with a standard Tru-Cut needle (BARD 18 G). Prototype and standard needles were used to puncture 4 different colon specimens in 10 randomized sites per colon. Needles were submerged into culture media to capture translocated bacteria. The media was cultured on blood agar and then the total amount of transferred bacteria was calculated for each needle. The primary outcome measure was the percent reduction of bacteria translocated by the prototype needles relative to the standard needle. Secondary outcome measures were the effects of tip design and coating on the percent reduction of translocated bacteria.Prototype needles reduced the number of translocated bacteria by, on average, 96.0% (95% confidence interval 93.0-97.7%;The Forsvall needle significantly reduces colonic bacterial translocation, suggesting that it could reduce infectious complications in prostate biopsy. A clinical trial has been initiated.

Severe coronavirus disease 2019 (COVID-19) can result in pneumonia and acute respiratory failure. Accumulation of mucus in the airways is a hallmark of the disease and can result in hypoxemia. Here, we show that quantitative proteome analysis of the sputum from severe patients with COVID-19 reveal high levels of neutrophil extracellular trap (NET) components, which was confirmed by microscopy. Extracellular DNA from excessive NET formation can increase sputum viscosity and lead to acute respiratory distress syndrome. Recombinant human DNase (Pulmozyme; Roche) has been shown to be beneficial in reducing sputum viscosity and improve lung function. We treated five patients pwith COVID-19 resenting acute symptoms with clinically approved aerosolized Pulmozyme. No adverse reactions to the drug were seen, and improved oxygen saturation and recovery in all severely ill patients with COVID-19 was observed after therapy. Immunofluorescence and proteome analysis of sputum and blood plasma samples after treatment revealed a marked reduction of NETs and a set of statistically significant proteome changes that indicate reduction of hemorrhage, plasma leakage and inflammation in the airways, and reduced systemic inflammatory state in the blood plasma of patients. Taken together, the results indicate that NETs contribute to acute respiratory failure in COVID-19 and that degrading NETs may reduce dependency on external high-flow oxygen therapy in patients. Targeting NETs using recombinant human DNase may have significant therapeutic implications in COVID-19 disease and warrants further studies.

Transrectal prostate biopsy (TRbx) transfers colonic bacteria into prostatic tissue, potentially causing infectious complications, including sepsis. Our objective was to determine whether biopsy needle shape, surface properties and sampling mechanism affect the number of bacteria transferred through the colon wall, and evaluate a novel needle with improved properties. The standard Tru-Cut biopsy needle used today was evaluated for mechanisms of bacterial transfer in a pilot study. A novel Tru-Cut needle (Forsvall needle prototype) was developed. TRbx was simulated using human colons ex-vivo. Four subtypes of the prototype needle were compared with a standard Tru-Cut needle (BARD 18 G). Prototype and standard needles were used to puncture 4 different colon specimens in 10 randomized sites per colon. Needles were submerged into culture media to capture translocated bacteria. The media was cultured on blood agar and then the total amount of transferred bacteria was calculated for each needle. The primary outcome measure was the percent reduction of bacteria translocated by the prototype needles relative to the standard needle. Secondary outcome measures were the effects of tip design and coating on the percent reduction of translocated bacteria. Prototype needles reduced the number of translocated bacteria by, on average, 96.0% (95% confidence interval 93.0-97.7%; p The Forsvall needle significantly reduces colonic bacterial translocation, suggesting that it could reduce infectious complications in prostate biopsy. A clinical trial has been initiated.

Meningitis is a potentially life-threatening infection characterized by the inflammation of the leptomeningeal membranes. Many different viral and bacterial pathogens can cause meningitis, with differences in mortality rates, risk of developing neurological sequelae and treatment options. Here we constructed a compendium of digital cerebrospinal fluid (CSF) proteome maps to define pathogen-specific host response patterns in meningitis. The results revealed a drastic and pathogen-type specific influx of tissue-, cell- and plasma proteins in the CSF, where in particular a large increase of neutrophil derived proteins in the CSF correlated with acute bacterial meningitis. Additionally, both acute bacterial and viral meningitis result in marked reduction of brain-enriched proteins. Generation of a multi-protein LASSO regression model resulted in an 18-protein panel of cell and tissue associated proteins capable of classifying acute bacterial meningitis and viral meningitis. The same protein panel also enabled classification of tick-borne encephalitis, a subgroup of viral meningitis, with high sensitivity and specificity. The work provides insights into pathogen specific host response patterns in CSF from different disease etiologies to support future classification of pathogen-type based on host response patterns in meningitis.

Histoplasmosis is a rare disease in nonendemic areas. We report a case of a 23-year-old male patient who presented with fever of unknown origin, cytopenias, organomegaly, and allograft dysfunction 4 months after renal transplant with father as donor. Bone marrow examination showed intracellular budding yeast cells, which was confirmed as histoplasmosis by culture of bone marrow biopsy sample. The patient was treated with intravenous liposomal amphotericin and responded well.

Neutrophil extracellular traps (NETs) are web-like antimicrobial structures consisting of DNA and granule derived antimicrobial proteins. Immunofluorescence microscopy and image-based quantification methods remain important tools to quantitate neutrophil extracellular trap formation. However, there are key limitations to the immunofluorescence-based methods that are currently available for quantifying NETs. Manual methods of image-based NET quantification are often subjective, prone to error and tedious for users, especially non-experienced users. Also, presently available software options for quantification are either semi-automatic or require training prior to operation. Here, we demonstrate the implementation of an automated immunofluorescence-based image quantification method to evaluate NET formation called NETQUANT. The software is easy to use and has a user-friendly graphical user interface (GUI). It considers biologically relevant parameters such as an increase in the surface area and DNA:NET marker protein ratio, and nuclear deformation to define NET formation. Furthermore, this tool is built as a freely available app, and allows for single-cell resolution quantification and analysis.

Neutrophil extracellular traps (NETs) that are extensive webs of DNA covered with antimicrobial proteins into the extracellular environment during infection or inflammation as a part of their defense arsenal. Image acquisition of fluorescently labeled NETs and subsequent image-based quantification is frequently used to analyze NET formation (NETosis) in response to various stimuli. However, there are important limitations in the present methods for quantification. Manual methods tend to be error-prone, tedious, and often quite subjective, whereas the software-rooted options are either semi-automatic or difficult to operate. Here, we present an automated and uncomplicated approach for quantifying NETs from fluorescence images, built as a freely available app for MATLAB®. It is based on detection of a set of clearly defined parameters, all related to the biological manifestation of NETs and allowing for single-cell resolution quantification and analysis.

Neutrophils are essential for host defense at the oral mucosa and neutropenia or functional neutrophil defects lead to disordered oral homeostasis. We found that neutrophils from the oral mucosa harvested from morning saliva had released neutrophil extracellular traps (undergone NETosis) in vivo. The NETosis was mediated through intracellular signals elicited by binding of sialyl Lewis(X) present on salival mucins to l-selectin on neutrophils. This led to rapid loss of nuclear membrane and intracellular release of granule proteins with subsequent neutrophil extracellular trap (NET) release independent of elastase and reduced NAD phosphate-oxidase activation. The saliva-induced NETs were more DNase-resistant and had higher capacity to bind and kill bacteria than NETs induced by bacteria or by phorbol-myristate acetate. Furthermore, saliva/sialyl Lewis(X) mediated signaling enhanced intracellular killing of bacteria by neutrophils. Saliva from patients with aphthous ulcers and Behçet disease prone to oral ulcers failed to induce NETosis, but for different reasons it demonstrated that disordered homeostasis in the oral cavity may result in deficient saliva-mediated NETosis.

Many bacterial pathogens have developed methods to overcome the defences of the host innate immune system. One such defence is the release of antimicrobial peptides (AMPs). Histones have been found to function as AMPs, in addition to their main biological function of packaging and organising DNA into nucleosomes. In this study, the Gram-positive anaerobic coccus Finegoldia magna was found to bind histones by Western blot and immunoprecipitation analysis. F. magna, which is normally a commensal of the skin and mucous membranes, is also known to act as an opportunistic pathogen and has been isolated from various clinical infection sites. It was found to bind to histones extracted from human skin epidermis through its surface and extracellular adhesion protein FAF. Through FAF binding, F. magna was protected from histone bactericidal activity. Furthermore, the histones were found to be degraded by SufA, a subtilisin-like extracellular serine protease of F. magna. Hence, the results of the present study will give more insight into how F. magna persists both as a commensal organism at the basement membrane of the skin and as an opportunistic pathogen during infection.

Background: Wounds in the oral cavity, constantly exposed to both saliva and bacteria, heal quickly without infection. Furthermore, during licking of skin wounds, saliva promotes wound healing and plays a role in keeping the wound free of infection. Objectives: To investigate whether saliva induces expression of antimicrobial peptides (AMPs) in human epidermal keratinocytes and whether saliva promotes clearance of intracellular bacteria in these cells. Methods: Expression of AMPs was investigated in the oral mucosa and ex vivo injured skin by immunohistochemistry. Human beta-defensin-3 expression was investigated in epidermal keratinocytes after saliva stimulation, using real-time polymerase chain reaction and immunofluorescence. Results: We found higher expression of AMPs in the oral mucosa than in the epidermis. Saliva accelerated the injury-induced expression of AMPs in human skin ex vivo and was a potent inducer of the expression of AMPs in epidermal keratinocytes. The expression of AMPs was induced by metalloproteinase-dependent epidermal growth factor receptor (EGFR) transactivation mediated by a salivary lipid. Saliva increased the intracellular clearance of Staphylococcus aureus in keratinocytes through EGFR activation. Conclusions: These findings suggest a previously unreported role of saliva in innate immunity and demonstrate for the first time that saliva induces gene expression in epidermal keratinocytes.

Streptococcal pharyngitis is among the most common bacterial infections, but the molecular mechanisms involved remain poorly understood. Here we investigate the interactions among three major players in streptococcal pharyngitis: streptococci, plasma, and saliva. We find that saliva activates the plasma coagulation system through both the extrinsic and the intrinsic pathways, entrapping the bacteria in fibrin clots. The bacteria escape the clots by activating host plasminogen. Our results identify a potential function for the intrinsic pathway of coagulation in host defense and a corresponding role for fibrinolysis in streptococcal immune evasion.

Table of contentsP1 D-Dimer in adult patients with presumed sepsis and their clinical outcomesSurinder Kumar Sharma, Anurag Rohatgi, Mansi BajajP2 Diagnosis of infection utilizing Acellix CD64Charles L. Sprung, Ricardo Calderon Morales, Harvey Kasdan, Allon Reiter, Tobias Volker, Julien MeissonnierP3 High levels of phenylcarboxylic acids reflect the severity in ICU patients and affect phagocytic activity of neutrophilsNatalia Beloborodova, Viktor Moroz, Aleksandra Bedova, Yulia Sarshor, Artem Osipov, Katerina ChernevskayaP4 The role of bacterial phenolic metabolites in mitochondrial dysfunctionNadezhda Fedotcheva, Ekaterina Chernevskaya, Natalia BeloborodovaP5 The early diagnosis of severe sepsis and judgment of rapid transport to critical care center: better prognostic factorHisashi Imahase, Kosuke C Yamada, Yuichiro Sakamoto, Miho Ohta, Ryota Sakurai, Mayuko Yahata, Mitsuru Umeka, Toru Miike, Hiroyuki Koami, Futoshi Nagashima, Takashi Iwamura, Satoshi InoueP6 Translational neuromodulation of the immune systemZhifeng Li, Dennis Grech, Patrick Morcillo, Alex Bekker, Luis UlloaP7 Pathway-level meta-analysis reveals transcriptional signature of septic shockSamanwoy Mukhopadhyay, Abhay D Pandey, Samsiddhi Bhattacharjee, Saroj K MohapatraP8 Antibiotic dosing in septic patients on the critical care unit - a literature reviewJulie K WilsonP9 Pandemic of Escherichia coli clone O25: H4-ST131 producing CTX-M-15 extended spectrum- β- lactamase- as serious cause of multidrug resistance extraintestinal pathogenic E. coli infections in IndiaSavita Jadhav, Rabindra Nath Misra, Nageswari Gandham, Kalpana Angadi, Chanda Vywahare, Neetu Gupta, Deepali DesaiP10 Detection and characterization of meningitis using a DDA-based mass spectrometry approachAnahita Bakochi, Tirthankar Mohanty, Adam Linder, Johan MalmströmP11 Diagnostic usefulness of lipid profile and procalcitonin in sepsis and trauma patientsDimple Anand, Seema Bhargava, Lalit Mohan Srivastava, Sumit RayP12 Heparin – a novel therapeutic in sepsis?Jane Fisher, Peter Bentzer, Adam LinderP13 Hypothalamic impairment is associated with vasopressin deficiency during sepsisLuis Henrique Angenendt da Costa, Nilton Nascimentos dos Santos Júnior Carlos Henrique Rocha Catalão, Maria José Alves da RochaP14 Presepsin (soluble CD14 subtype) is a dependable prognostic marker in critical septic patientsAlfredo Focà, Cinzia Peronace, Giovanni Matera, Aida Giancotti, Giorgio Settimo Barreca, Angela Quirino, Maria Teresa Loria, Pio Settembre, Maria Carla Liberto, Bruno AmanteaP15 Safety and efficacy of gelatin-containing solutions versus crystalloids and albumin - a systematic review with quantitative and qualitative summariesChristiane Hartog, Christiane Hartog, Claudia Moeller, Carolin Fleischmann, Daniel Thomas-Rueddel, Vlasislav Vlasakov, Bram Rochwerg, Philip Theurer, Konrad ReinhartP16 Immunomodulatory properties of peripheral blood mesenchymal stem cells following endotoxin stimulation in an equine modelAnna E. Smith, Sandra D. TaylorP17 Frequency and outcome of early sepsis-associated coagulopathyChristopher Da Costa, Amanda Radford, Terry Lee, Joel Singer, John Boyd, David Fineberg, Mark Williams, James A Russell

Pathogenic mycobacteria reside in, and are in turn controlled by, macrophages. However, emerging data suggest that neutrophils also play a critical role in innate immunity to tuberculosis, presumably by their different antibacterial granule proteins. In this study, we purified neutrophil azurophil and specific granules and systematically analyzed the antimycobacterial activity of some purified azurophil and specific granule proteins against M. smegmatis, M. bovis-BCG and M. tuberculosis H37Rv. Using gel overlay and colony forming unit assays we showed that the defensin-depleted azurophil granule proteins (AZP) were more active against mycobacteria compared to other granule proteins and cytosolic proteins. The proteins showing antimycobacterial activity were identified by MALDI-TOF mass spectrometry. Electron microscopic studies demonstrate that the AZP disintegrate bacterial cell membrane resulting in killing of mycobacteria. Exogenous addition of AZP to murine macrophage RAW 264.7, THP-1 and peripheral blood monocyte-derived macrophages significantly reduced the intracellular survival of mycobacteria without exhibiting cytotoxic activity on macrophages. Immunofluorescence studies showed that macrophages actively endocytose neutrophil granular proteins. Treatment with AZP resulted in increase in co-localization of BCG containing phagosomes with lysosomes but not in increase of autophagy. These data demonstrate that neutrophil azurophil proteins may play an important role in controlling intracellular survival of mycobacteria in macrophages. Citation: Jena P, Mohanty S, Mohanty T, Kallert S, Morgelin M, et al. (2012) Azurophil Granule Proteins Constitute the Major Mycobactericidal Proteins in Human Neutrophils and Enhance the Killing of Mycobacteria in Macrophages. PLoS ONE 7(12): e50345. doi:10.1371/journal.pone.0050345