Nitrate transport to coastal Monterey Bay : investigating source inputs from Elkhorn Slough

Nitrate transport from Elkhorn Slough (ES) to the nearshore surface waters of Monterey Bay is examined using two years of time-series data from the Land-Ocean Biogeochemical Observatory (LOBO). Hourly nitrate, temperature and salinity measurements from nearshore moorings 2.5 km north (summer, 2008) and 2.5 km south (summer– fall, 2009, winter 2010) of the Moss Landing Harbor entrance at 20-m depth were monitored with the objective of observing high nitrate events associated with terrestrial-sourced waters. Nearshore nitrate supply from ES was quantified in comparison to upwelling and internal waves based on estimates of volume transport and average nitrate concentration observed at LOBO moorings. One distinct runoff event, October 13-14, 2009, was observed during the two-year study period. Data from the LOBO mooring array was used to assess the impact of this winter-type event in comparison to the longer time-series of summer conditions. Despite intensive agricultural-based nitrate loading within Old Salinas River, the summer contribution to the nearshore nitrate budget from the Elkhorn Slough system was over an order of magnitude less than upwelling and 4 to 13-fold less than internal waves. While rates of nitrate transport vary seasonally, assessment of nitrate transport mechanisms to coastal Monterey Bay in the summer to early fall is essential to understanding the dynamics of extreme algal blooms that typically occur during these months

Oral Ulceration in Behçet's Disease: An Investigation of Neutrophil Elastase and Its Inhibitors

PhdBehçet’s disease (BD) is a vasculitis of unknown aetiology typified by recurrent oral and genital ulcers, skin and ocular lesions. Debilitating manifestations can also affect vascular, gastrointestinal and neurological systems. Previous BD investigations showed increased circulating neutrophils and neutrophil elastase (NE), a serine protease. NE can digest connective tissues compromising their integrity if not regulated. In this study, NE and its two main inhibitors, secretory leukocyte protease inhibitor (SLPI) and alpha1- antitrypsin (α1AT), were investigated to determine if NE dysregulation is triggering oral mucosal damage. Findings were compared to healthy controls (HC) and recurrent aphthous stomatitis (RAS) patients, a disorder of episodic oral ulceration. FlowCytoMixTMmultiplex-assays compared saliva and serum inflammatory cytokines measurements where salivary levels reflected disease activity and correlated with published serum levels. Salivary NE, SLPI, and α1AT were measured by ELISA. Patients with oral ulcers had increased NE. Unexpectedly, BDq (quiescent, without ulceration) had increased NE, but SLPI was significantly lower than RASq and HC. RASq NE levels were similar to HC. Overall, NE correlated with α1AT levels, but showed an inverse relationship with SLPI. Quantitative PCR revealed significantly increased SLPI mRNA expression in both BDq and RASq buccal epithelium. High mRNA/low SLPI protein expression during ulceration could be explained by deficient translation, blocked ELISA antibody binding, or SLPI depletion. Despite high α1AT, all study groups had enzymatically active salivary NE which was successfully inhibited by recombinant SLPI. Confocal microscopy revealed BD patients’ blood neutrophils readily release neutrophil extracellular traps (NETs) in vitro compared to HCs. Antimicrobial NETs have mixed granule contents coating decondensed chromatin fibres and are associated with autoimmunity. During NET production, our novel observation that intracellular SLPI but not α1AT co-localised with NE suggests a regulatory role. This study supports the theory that a protease-antiprotease imbalance may play a role in BD oral and systemic pathology.James Paget Studentshi

Differential susceptibility of PCR reactions to inhibitors: an important and unrecognised phenomenon

PCR inhibition by nucleic acid extracts is a well known yet poorly described phenomenon. Inhibition assessment generally depends on the assumption that inhibitors affect all PCR reactions to the same extent; i.e. that the reaction of interest and the control reaction are equally susceptible to inhibition. To test this assumption we performed inhibition assessment on DNA extracts from human urine samples, fresh urine and EDTA using different PCR reactions

Systemic and Lower Respiratory Tract Immunity to SARS-CoV-2 Omicron and Variants in Pediatric Severe COVID-19 and Mis-C

Mucosal immunity plays an important role in the control of viral respiratory infections like SARS-CoV-2. While systemic immune responses against the SARS-2-CoV-2 have been studied in children, there is no information on mucosal antibody response, especially in the lower respiratory tract of children coronavirus disease 2019 (COVID-19) and post-infectious multisystem inflammatory syndrome in children (MIS-C) against emerging SARS-CoV-2 variants. Therefore, we evaluated neutralizing antibody responses in paired plasma and endotracheal aspirates of pediatric severe, acute COVID-19 or MIS-C patients against SARS-CoV-2 WA1/2020, as well as against variants of concern (VOCs). Neutralizing antibody responses against the SARS-CoV-2 WA1/2020 strain in pediatric plasma were 2-fold or 35-fold higher compared with the matched endotracheal aspirate in COVID-19 or MIS-C patients, respectively. In contrast to plasma, neutralizing antibody responses against the VOCs and variants of interest (VOIs) in endotracheal aspirates were lower, with only one endotracheal aspirate demonstrating neutralizing titers against the Iota, Kappa, Beta, Gamma, and Omicron variants. In conclusion, our findings suggest that children and adolescents with severe COVID-19 or MIS-C have weak mucosal neutralizing antibodies in the trachea against circulating SARS-CoV-2 Omicron and other VOCs, which may have implications for recovery and for re-infection with emerging SARS-CoV-2 variants

Transcriptomic profiles of multiple organ dysfunction syndrome phenotypes in pediatric critical influenza

BackgroundInfluenza virus is responsible for a large global burden of disease, especially in children. Multiple Organ Dysfunction Syndrome (MODS) is a life-threatening and fatal complication of severe influenza infection.MethodsWe measured RNA expression of 469 biologically plausible candidate genes in children admitted to North American pediatric intensive care units with severe influenza virus infection with and without MODS. Whole blood samples from 191 influenza-infected children (median age 6.4 years, IQR: 2.2, 11) were collected a median of 27 hours following admission; for 45 children a second blood sample was collected approximately seven days later. Extracted RNA was hybridized to NanoString mRNA probes, counts normalized, and analyzed using linear models controlling for age and bacterial co-infections (FDR q<0.05).ResultsComparing pediatric samples collected near admission, children with Prolonged MODS for ≥7 days (n=38; 9 deaths) had significant upregulation of nine mRNA transcripts associated with neutrophil degranulation (RETN, TCN1, OLFM4, MMP8, LCN2, BPI, LTF, S100A12, GUSB) compared to those who recovered more rapidly from MODS (n=27). These neutrophil transcripts present in early samples predicted Prolonged MODS or death when compared to patients who recovered, however in paired longitudinal samples, they were not differentially expressed over time. Instead, five genes involved in protein metabolism and/or adaptive immunity signaling pathways (RPL3, MRPL3, HLA-DMB, EEF1G, CD8A) were associated with MODS recovery within a week.ConclusionThus, early increased expression of neutrophil degranulation genes indicated worse clinical outcomes in children with influenza infection, consistent with reports in adult cohorts with influenza, sepsis, and acute respiratory distress syndrome

Exuberant fibroblast activity compromises lung function via ADAMTS4

© 2020, The Author(s), under exclusive licence to Springer Nature Limited. Severe respiratory infections can result in acute respiratory distress syndrome (ARDS)1. There are no effective pharmacological therapies that have been shown to improve outcomes for patients with ARDS. Although the host inflammatory response limits spread of and eventually clears the pathogen, immunopathology is a major contributor to tissue damage and ARDS1,2. Here we demonstrate that respiratory viral infection induces distinct fibroblast activation states, which we term extracellular matrix (ECM)-synthesizing, damage-responsive and interferon-responsive states. We provide evidence that excess activity of damage-responsive lung fibroblasts drives lethal immunopathology during severe influenza virus infection. By producing ECM-remodelling enzymes—in particular the ECM protease ADAMTS4—and inflammatory cytokines, damage-responsive fibroblasts modify the lung microenvironment to promote robust immune cell infiltration at the expense of lung function. In three cohorts of human participants, the levels of ADAMTS4 in the lower respiratory tract were associated with the severity of infection with seasonal or avian influenza virus. A therapeutic agent that targets the ECM protease activity of damage-responsive lung fibroblasts could provide a promising approach to preserving lung function and improving clinical outcomes following severe respiratory infections

Publisher Correction: Exuberant fibroblast activity compromises lung function via ADAMTS4 (Nature, (2020), 587, 7834, (466-471), 10.1038/s41586-020-2877-5)

© 2020, The Author(s), under exclusive licence to Springer Nature Limited. An amendment to this paper has been published and can be accessed via a link at the top of the paper

A blood atlas of COVID-19 defines hallmarks of disease severity and specificity.

Treatment of severe COVID-19 is currently limited by clinical heterogeneity and incomplete description of specific immune biomarkers. We present here a comprehensive multi-omic blood atlas for patients with varying COVID-19 severity in an integrated comparison with influenza and sepsis patients versus healthy volunteers. We identify immune signatures and correlates of host response. Hallmarks of disease severity involved cells, their inflammatory mediators and networks, including progenitor cells and specific myeloid and lymphocyte subsets, features of the immune repertoire, acute phase response, metabolism, and coagulation. Persisting immune activation involving AP-1/p38MAPK was a specific feature of COVID-19. The plasma proteome enabled sub-phenotyping into patient clusters, predictive of severity and outcome. Systems-based integrative analyses including tensor and matrix decomposition of all modalities revealed feature groupings linked with severity and specificity compared to influenza and sepsis. Our approach and blood atlas will support future drug development, clinical trial design, and personalized medicine approaches for COVID-19