Novel sulfur isotope analyses constrain sulfurized porewater fluxes as a minor component of marine dissolved organic matter.

Marine dissolved organic matter (DOM) is a major reservoir that links global carbon, nitrogen, and phosphorus. DOM is also important for marine sulfur biogeochemistry as the largest water column reservoir of organic sulfur. Dissolved organic sulfur (DOS) can originate from phytoplankton-derived biomolecules in the surface ocean or from abiotically "sulfurized" organic matter diffusing from sulfidic sediments. These sources differ in 34S/32S isotope ratios (δ34S values), with phytoplankton-produced DOS tracking marine sulfate (21‰) and sulfurized DOS mirroring sedimentary porewater sulfide (∼0 to -10‰). We measured the δ34S values of solid-phase extracted (SPE) DOM from marine water columns and porewater from sulfidic sediments. Marine DOMSPE δ34S values ranged from 14.9‰ to 19.9‰ and C:S ratios from 153 to 303, with lower δ34S values corresponding to higher C:S ratios. Marine DOMSPE samples showed consistent trends with depth: δ34S values decreased, C:S ratios increased, and δ13C values were constant. Porewater DOMSPE was 34S-depleted (∼-0.6‰) and sulfur-rich (C:S ∼37) compared with water column samples. We interpret these trends as reflecting at most 20% (and on average ∼8%) contribution of abiotic sulfurized sources to marine DOSSPE and conclude that sulfurized porewater is not a main component of oceanic DOS and DOM. We hypothesize that heterogeneity in δ34S values and C:S ratios reflects the combination of sulfurized porewater inputs and preferential microbial scavenging of sulfur relative to carbon without isotope fractionation. Our findings strengthen links between oceanic sulfur and carbon cycling, supporting a realization that organic sulfur, not just sulfate, is important to marine biogeochemistry.

Clinical, experimental and pathophysiological effects of Yaq-001: a non-absorbable, gut-restricted adsorbent in models and patients with cirrhosis.

OBJECTIVE: Targeting bacterial translocation in cirrhosis is limited to antibiotics with risk of antimicrobial resistance. This study explored the therapeutic potential of a non-absorbable, gut-restricted, engineered carbon bead adsorbent, Yaq-001 in models of cirrhosis and acute-on-chronic liver failure (ACLF) and, its safety and tolerability in a clinical trial in cirrhosis. DESIGN: Performance of Yaq-001 was evaluated in vitro. Two-rat models of cirrhosis and ACLF, (4 weeks, bile duct ligation with or without lipopolysaccharide), receiving Yaq-001 for 2 weeks; and two-mouse models of cirrhosis (6-week and 12-week carbon tetrachloride (CCl4)) receiving Yaq-001 for 6 weeks were studied. Organ and immune function, gut permeability, transcriptomics, microbiome composition and metabolomics were analysed. The effect of faecal water on gut permeability from animal models was evaluated on intestinal organoids. A multicentre, double-blind, randomised, placebo-controlled clinical trial in 28 patients with cirrhosis, administered 4 gr/day Yaq-001 for 3 months was performed. RESULTS: Yaq-001 exhibited rapid adsorption kinetics for endotoxin. In vivo, Yaq-001 reduced liver injury, progression of fibrosis, portal hypertension, renal dysfunction and mortality of ACLF animals significantly. Significant impact on severity of endotoxaemia, hyperammonaemia, liver cell death, systemic inflammation and organ transcriptomics with variable modulation of inflammation, cell death and senescence in the liver, kidneys, brain and colon was observed. Yaq-001 reduced gut permeability in the organoids and impacted positively on the microbiome composition and metabolism. Yaq-001 regulated as a device met its primary endpoint of safety and tolerability in the clinical trial. CONCLUSIONS: This study provides strong preclinical rationale and safety in patients with cirrhosis to allow clinical translation. TRIAL REGISTRATION NUMBER: NCT03202498.

Evaluation of CirrhoCare® - a digital health solution for home management of individuals with cirrhosis.

BACKGROUND & AIMS: Individuals with cirrhosis discharged from hospital following acute decompensation are at high risk of new complications. This study aimed to assess the feasibility and potential clinical benefits of remote management of individuals with acutely decompensated cirrhosis using CirrhoCare®. METHODS: Individuals with cirrhosis with acute decompensation were followed up with CirrhoCare® and compared with contemporaneous matched controls, managed with standard follow-up. Commercially available monitoring devices were linked to the smartphone CirrhoCare® app, for daily recording of heart rate, blood pressure, weight, % body water, cognitive function (CyberLiver Animal Recognition Test [CL-ART] app), self-reported well-being, and intake of food, fluid, and alcohol. The app had 2-way patient-physician communication. Independent external adjudicators assessed the appropriateness of CirrhoCare®-based decisions. RESULTS: Twenty individuals with cirrhosis were recruited to CirrhoCare® (mean age 59 ± 10 years, 14 male, alcohol-related cirrhosis [80%], mean model for end-stage liver disease-sodium [MELD-Na] score 16.1 ± 4.2) and were not statistically different to 20 contemporaneous controls. Follow-up was 10.1 ± 2.4 weeks. Fifteen individuals showed good engagement (≥4 readings/week), 2 moderate (2-3/week), and 3 poor (<2/week). In a usability questionnaire, the median score was ≥9 for all questions. Five CirrhoCare®-managed individuals had 8 readmissions over a median of 5 (IQR 3.5-11) days, and none required hospitalisation for >14 days. Sixteen other CirrhoCare®-guided patient contacts were made, leading to clinical interventions that prevented further progression. Appropriateness was confirmed by adjudicators. Controls had 13 readmissions in 8 individuals, lasting a median of 7 (IQR 3-15) days with 4 admissions of >14 days. They had 6 unplanned paracenteses compared with 1 in the CirrhoCare® group. CONCLUSIONS: This study demonstrates that CirrhoCare® is feasible for community management of individuals with decompensated cirrhosis with good engagement and clinically relevant alerts to new decompensating events. CirrhoCare®-managed individuals have fewer and shorter readmissions justifying larger controlled clinical trials. IMPACT AND IMPLICATIONS: As the burden of cirrhosis grows worldwide, increasing demands are being placed on limited healthcare resources, necessitating the adoption of more sustainable care models that allow for at-home patient management. The CirrhoCare® management system was developed to fill this care gap, deploying a novel combination of hardware, apps, and algorithms, to monitor and intervene in individuals at risk of new decompensation. This study highlights the possibility of reducing hospital readmissions for cirrhosis by optimising specialist community care, reducing the need for interventions such as paracentesis, while providing a more sustainable care pathway that is acceptable to patients. However, given the pilot and non-randomised nature of this study, the outcomes require further validation in a larger randomised controlled trial, to assess both clinical effectiveness and cost-effectiveness. Moreover, the data generated will also facilitate data modelling and further research to refine the CirrhoCare® algorithms to increase their detection sensitivity and utility.

Prognostic Role of Liver Biopsy in Patients With Severe Indeterminate Acute Hepatitis.

BACKGROUND AND AIMS: Severe indeterminate acute hepatitis (sIAH) is a poorly understood rare disease with no specific therapy. This study aims to define the clinicopathological characteristics of sIAH and the role of liver biopsy in determining prognosis. METHODS: Patients with sIAH admitted to a single center between 2010 and 2019 were included. Histopathological patterns of liver biopsies were reviewed by 2 histopathologists, and key findings further were specified by multiplex immunofluorescence. Patients that died or underwent liver transplantation were analyzed as nonsurvivors. RESULTS: Of 294 patients with acute hepatitis, 43 with sIAH were included. Seventeen (39.5%) underwent liver transplantation and 7 (16.2%) died within 3 months. Multilobular necrosis was the predominant histopathological feature, being significantly more frequent in nonsurvivors (62.5% vs 21.1%; P = .016). Necrotic areas showed low HNF4α and Ki67 expression but high expression of CK19 and cell death markers identifying areas of severe tissue injury and inadequate regenerative response. Patients with multilobular necrosis had higher international normalized ratio, Model for End-Stage Liver Disease, and Model for End-Stage Liver Disease-Sodium scores compared with those without (P values for all markers <.05). Multivariate Cox analysis revealed that multilobular necrosis (hazard ratio, 3.675; 95% confidence interval, 1.322-10.211) and lower body mass index (hazard ratio, 0.916; 95% confidence interval, 0.848-0.991) independently predicted death or transplantation. CONCLUSIONS: The results of this study provide novel insights into the important role of liver biopsy in sIAH patients, suggesting that the presence of multilobular necrosis is an early indicator of poor prognosis.

Presence of multilobular necrosis on liver biopsy identifies corticosteroid responsiveness in acute indeterminate hepatitis.

BACKGROUND AND AIMS: Treatment of patients with severe indeterminate hepatitis (IAH) is an unmet need. Corticosteroids are often used in the management of these patients but criteria for the selection of patients for this intervention are arbitrary. The aims of this study were to analyse the clinical and pathological features of patients with IAH to define predictors of corticosteroid responsiveness. METHODS: This study included consecutive patients with acute indeterminate hepatitis admitted to a single hospital and underwent a liver biopsy. The clinical manifestation and histopathological features of steroid and non-steroid groups were compared and their relationship with corticosteroids response was evaluated. RESULTS: Forty-eight patients were included, 24 (50%) recovered and the other half underwent liver transplantation or died within 3-months. Of the 48 cases, 24 received corticosteroids (initial dose of 45 ± 12 mg prednisolone). Corticosteroids were initiated 2.7 ± 3.8 days after admission. Liver biopsy was performed 2-days (median, IQR 1-3) after admission. Fifteen (62.5%) patients receiving corticosteroids survived without transplantation compared with 9 (37.5%) that did not receive steroids (P = .149). In those with multilobular necrosis, 50% reduction in the death/transplantation rate was observed after steroid treatment (P = .018). In patients without multilobular necrosis and with or without perivenulitis, corticosteroids did not impact the outcome. Response to corticosteroids was independent of the MELD score. CONCLUSIONS: The presence of multilobular necrosis on liver biopsy helps identify a subgroup of IAH cases who may benefit from the administration of corticosteroids.

Human pharmacokinetics of XBD173 and etifoxine distinguish their potential for pharmacodynamic effects mediated by translocator protein.

XBD173 and etifoxine are translocator protein (TSPO) ligands that modulate inflammatory responses in preclinical models. Limited human pharmacokinetic data is available for either molecule, and the binding affinity of etifoxine for human TSPO is unknown. To allow for design of human challenge experiments, we derived pharmacokinetic data for orally administered etifoxine (50 mg 3 times daily) and XBD173 (90 mg once daily) and determined the binding affinity of etifoxine for TSPO. For XBD173, maximum plasma concentration and free fraction measurements predicted a maximal free concentration of 1.0 nM, which is similar to XBD173 binding affinity. For etifoxine, maximum plasma concentration and free fraction measurements predicted a maximal free concentration of 0.31 nM, substantially lower than the Ki for etifoxine in human brain derived here (7.8 µM, 95% CI 4.5-14.6 µM). We conclude that oral XBD173 dosing at 90 mg once daily will achieve pharmacologically relevant TSPO occupancy. However, the occupancy is too low for TSPO mediated effects after oral dosing of etifoxine at 50 mg 3 times daily.

A highly versatile fungal glucosyltransferase for specific production of quercetin-7-O-ß-D-glucoside and quercetin-3-O-ß-D-glucoside in different hosts.

Glycosylation is an effective way to improve the water solubility of natural products. In this work, a novel glycosyltransferase gene (BbGT) was discovered from Beauveria bassiana ATCC 7159 and heterologously expressed in Escherichia coli. The purified enzyme was functionally characterized through in vitro enzymatic reactions as a UDP-glucosyltransferase, converting quercetin to five monoglucosylated and one diglucosylated products. The optimal pH and temperature for BbGT are 35 ℃ and 8.0, respectively. The activity of BbGT was stimulated by Ca2+, Mg2+, and Mn2+, but inhibited by Zn2+. BbGT enzyme is flexible and can glycosylate a variety of substrates such as curcumin, resveratrol, and zearalenone. The enzyme was also expressed in other microbial hosts including Saccharomyces cerevisiae, Pseudomonas putida, and Pichia pastoris. Interestingly, the major glycosylation product of quercetin in E. coli, P. putida, and P. pastoris was quercetin-7-O-ß-D-glucoside, while the enzyme dominantly produced quercetin-3-O-ß-D-glucoside in S. cerevisiae. The BbGT-harboring E. coli and S. cerevisiae strains were used as whole-cell biocatalysts to specifically produce the two valuable quercetin glucosides, respectively. The titer of quercetin-7-O-ß-D-glucosides was 0.34 ± 0.02 mM from 0.83 mM quercetin in 24 h by BbGT-harboring E. coli. The yield of quercetin-3-O-ß-D-glucoside was 0.22 ± 0.02 mM from 0.41 mM quercetin in 12 h by BbGT-harboring S. cerevisiae. This work thus provides an efficient way to produce two valuable quercetin glucosides through the expression of a versatile glucosyltransferase in different hosts. KEY POINTS: • A highly versatile glucosyltransferase was identified from B. bassiana ATCC 7159. • BbGT converts quercetin to five mono- and one di-glucosylated derivatives in vitro. • Different quercetin glucosides were produced by BbGT in E. coli and S. cerevisiae.

Sulfur isotope analysis of cysteine and methionine via preparatory liquid chromatography and elemental analyzer isotope ratio mass spectrometry.

RATIONALE: Sulfur isotope analysis of organic sulfur-containing molecules has previously been hindered by challenging preparatory chemistry and analytical requirements for large sample sizes. The natural-abundance sulfur isotopic compositions of the sulfur-containing amino acids, cysteine and methionine, have therefore not yet been investigated despite potential utility in biomedicine, ecology, oceanography, biogeochemistry, and other fields. METHODS: Cysteine and methionine were subjected to hot acid hydrolysis followed by quantitative oxidation in performic acid to yield cysteic acid and methionine sulfone. These stable, oxidized products were then separated by reversed-phase high-performance liquid chromatography (HPLC) and verified via offline liquid chromatography/mass spectrometry (LC/MS). The sulfur isotope ratios (δ34 S values) of purified analytes were then measured via combustion elemental analyzer coupled to isotope ratio mass spectrometry (EA/IRMS). The EA was equipped with a temperature-ramped chromatographic column and programmable helium carrier flow rates. RESULTS: On-column focusing of SO2 in the EA/IRMS system, combined with reduced He carrier flow during elution, greatly improved sensitivity, allowing precise (0.1-0.3‰ 1 s.d.) δ34 S measurements of 1 to 10 µg sulfur. We validated that our method for purification of cysteine and methionine was negligibly fractionating using amino acid and protein standards. Proof-of-concept measurements of fish muscle tissue and bacteria demonstrated differences up to 4‰ between the δ34 S values of cysteine and methionine that can be connected to biosynthetic pathways. CONCLUSIONS: We have developed a sensitive, precise method for measuring the natural-abundance sulfur isotopic compositions of cysteine and methionine isolated from biological samples. This capability opens up diverse applications of sulfur isotopes in amino acids and proteins, from use as a tracer in organisms and the environment, to fundamental aspects of metabolism and biosynthesis.

Self-management and transition among adolescents/young adults with chronic or end-stage kidney disease.

BACKGROUND: Adolescents/young adults (AYA) with chronic kidney disease (CKD) or end-stage kidney disease (ESKD) are at risk for poor health outcomes related to self-management. To improve their health and quality of life, AYA must build self-management (for those in the pediatric- and adult-focused setting) and/or health care transition (HCT) skills (for those in the pediatric setting). METHODS: Self-management and/or HCT encompass a variety of domains that must be tailored to each individual. Annual assessments should begin between the ages of 12 and 14 and continue in the adult-focused setting until patients have achieved demonstrated self-management and/or HCT skills mastery. These assessments will guide interventions that are congruent in terms of literacy, development and culture. Facilitation of this process from the perspective of both the pediatric and the adult health-care systems is described. CONCLUSIONS: Deficiencies and barriers to self-management and/or HCT for AYA with ESKD remain. There is no consensus on the definition of successful HCT preparation, with few tools to assess transition readiness and/or self-management. It is important for health providers to promote the self-management and/or health-care transition skills of AYA with ESKD. Customization of these activities and involvement of the whole family will contribute towards better health-related quality of life and patient outcomes.

Self-Management and Transition Readiness Assessment: Concurrent, Predictive and Discriminant Validation of the STARx Questionnaire.

INTRODUCTION: The STARx Questionnaire was designed with patient and provider input, to measure self-management and transition skills in adolescents and young adults (AYA) with chronic health conditions. With proven reliability and an empirically-based factor structure, the self-report STARx Questionnaire requires further validation to demonstrate its clinical and research utility. In this study we examine the concurrent, predictive, and discriminant validity of the STARx Questionnaire. METHODS: To examine concurrent validity, the STARx Questionnaire was compared to two other published transition readiness tools. Predictive validity was examined using linear regressions between the STARx Total Score and literacy, medication adherence, quality of life, and health services use. Discriminant validity was examined by comparing the performance of three chronic illness conditions on the STARx Total Score and associated subscales. RESULTS: The STARx Questionnaire and its subscales positively correlated with the scores for both transition readiness tools reflecting strong concurrent validity. The STARx Questionnaire also correlated positively with the literacy, self-efficacy, and adherence measures indicating strong predictive validity; however, it did not correlate with either quality of life or health care utilization. The performance of AYA across three different clinical conditions was not significant, indicating the clinical utility of this HCT tool for a variety of chronic health conditions. CONCLUSION: The strong validity of the STARx Questionnaire, in tandem with its strong reliability, indicated adequate psychometric properties for this generic self-report measure. These strong psychometric properties should contribute to the STARx being a viable measure of health care transition for both research and clinical purposes.

Hospital admissions caused by adverse drug events: an Australian prospective study.

OBJECTIVE: To assess the frequency of adverse drug event (ADE)-related admissions (ADE-RAs) during a prospective medical record review of patients admitted to a metropolitan tertiary referral hospital. METHODS: Potential ADE-RA cases were identified by examination of case records of randomly selected patients. Cases were assessed by an expert panel to measure study outcomes, which were the frequency (ADEs and ADE-RAs) as well as type, likelihood of causality, severity, avoidability and detection of ADEs. RESULTS: Of the 370 subjects, 59 (16.0%) had a confirmed ADE-RA, with 15 (4.1%) of these serious and preventable. The 59 ADE-RAs were a result of 72 discreet ADEs. Adverse drug reactions were the most common type of ADE, followed by non-compliance. Of the 72 discreet ADEs, 31.9% were classified as 'probable' or 'highly probable'. Most ADEs (54.2%) were classified as 'definitely avoidable', 34.7% were classified as 'severe' and 21.8% were classified as both 'definitely avoidable' and 'severe'. Half the ADEs were detected after the patient had been admitted and most were detected by medical practitioners. Antineoplastics followed by antidiabetic agents were most frequently implicated. CONCLUSIONS: Implementing a systems approach that involves multiple strategies, such as improving tertiary-to-primary care information transfer and promoting medication adherence through education programs, is necessary to tackle the problem of avoidable ADE-RAs and the associated cost burden. WHAT IS KNOWN ABOUT THE TOPIC? It is estimated that 2-3% of Australian hospital admissions are due to adverse drug events (ADEs), but recent data are lacking. According to the Australian Statistics on Medicines, over 250 million prescriptions were dispensed in 2007, compared with just under 180 million in 1997. This 40% increase in drug utilisation over the 10 years surpasses the Australian population growth of 14% in the same period. An increase in drug use per person indicates that the rate of ADEs and possible ADE-related admissions (ADE-RAs) is likely to have increased. WHAT DOES THIS PAPER ADD? This prospective study was conducted at a large Australian metropolitan teaching hospital and we report that 59 of 370 participants (16.0%) presenting to the Emergency Department had a confirmed ADE-RA, with 15 (4.1%) presenting with a serious and preventable ADE-RA. WHAT ARE THE IMPLICATIONS FOR PRACTITIONERS? The findings of this study support implementing a systems approach involving multiple strategies to tackle the problem of avoidable ADE-RAs and the associated cost burden. This study reveals that half the ADEs were not detected until after the admission process, which reinforces the importance of focusing efforts towards preventing ADE-RAs and detecting ADE-RAs through measures such as those recommended in the Australian Pharmaceutical Advisory Council guiding principles.

Why aquatic scientists should use sulfur stable isotope ratios (ẟ34S) more often.

Over the last few decades, measurements of light stable isotope ratios have been increasingly used to answer questions across physiology, biology, ecology, and archaeology. The vast majority analyse carbon (δ13C) and nitrogen (δ15N) stable isotopes as the 'default' isotopes, omitting sulfur (δ34S) due to time, cost, or perceived lack of benefits and instrumentation capabilities. Using just carbon and nitrogen isotopic ratios can produce results that are inconclusive, uncertain, or in the worst cases, even misleading, especially for scientists that are new to the use and interpretation of stable isotope data. Using sulfur isotope values more regularly has the potential to mitigate these issues, especially given recent advancements that have lowered measurement barriers. Here we provide a review documenting case studies with real-world data, re-analysing different biological topics (i.e. niche, physiology, diet, movement and bioarchaeology) with and without sulfur isotopes to highlight the various strengths of this stable isotope for various applications. We also include a preliminary meta-analysis of the trophic discrimination factor (TDF) for sulfur isotopes, which suggest small (mean -0.4 ± 1.7 ‰ SD) but taxa-dependent mean trophic discrimination. Each case study demonstrates how the exclusion of sulfur comes at the detriment of the results, often leading to very different outputs, or missing valuable discoveries entirely. Given that studies relying on carbon and nitrogen stable isotopes currently underpin most of our understanding of various ecological processes, this has concerning implications. Collectively, these examples strongly suggest that researchers planning to use carbon and nitrogen stable isotopes for their research should incorporate sulfur where possible, and that the new 'default' isotope systems for aquatic science should now be carbon, nitrogen, and sulfur.

HPV8-induced STAT3 activation led keratinocyte stem cell expansion in human actinic keratoses.

Despite epidermal turnover, the skin is host to a complex array of microbes including viruses, such as the human papillomavirus (HPV), which must infect and manipulate skin keratinocyte stem cells (KSC) to survive. This crosstalk between the virome and KSC populations remains largely unknown. Here, we investigated the effect of HPV8 on KSCs using various mouse models. We observed that the HPV8 early region gene E6 specifically caused Lrig1+ hair follicle junctional zone KSC proliferation and expansion, which would facilitate viral transmission. Within Lrig1+ KSCs specifically, HPV8 E6 bound intracellular p300 to phosphorylate the STAT3 transcriptional regulatory node. This induces ΔNp63 expression, resulting in KSC expansion into the overlying epidermis. HPV8 was associated with 70% of human actinic keratoses (AK). Together these results define the "hit and run" mechanism for HPV8 in human actinic keratosis as an expansion of KSCs, which lacks melanosome protection and is thus susceptible to sun-light-induced malignant transformation.

Negative impact of the pandemic on hospital admissions, morbidity and early mortality for acute cirrhosis decompensation.

INTRODUCTION: The global pandemic has diverted resources away from management of chronic diseases, including cirrhosis. While there is increasing knowledge on COVID-19 infection in liver cirrhosis, little is described on the impact of the pandemic on decompensated cirrhosis admissions and outcomes, which was the aim of this study. METHODS: A single-centre, retrospective study, evaluated decompensated cirrhosis admissions to a tertiary London hepatology and transplantation centre, from October 2018 to February 2021. Patients were included if they had an admission with cirrhosis decompensation defined as new-onset jaundice or ascites, infection, encephalopathy, portal hypertensive bleeding or renal dysfunction. RESULTS: The average number of admissions stayed constant between the pre-COVID-19 (October 2018-February 2020) and COVID-19 periods (March 2020-February 2021). Patients transferred in from secondary centres had consistently higher severity scores during the COVID-19 period (UK Model for End-Stage Liver Disease 58 vs 54; p=0.007, Model for End-Stage Liver Disease-Sodium 22 vs 18; p=0.006, EF-CLIF Acute Decompensation (AD) score 55.0 vs 51.0; p=0.055). Of those admitted to the intensive care without acute-on-chronic liver failure, there was a significant increase in AD scores during the COVID-19 period (58 vs 48, p=0.009). In addition, there was a trend towards increased hospital readmission rates during the COVID-19 period (29.5% vs 21.5%, p=0.067). When censored at 30 days, early mortality postdischarge was significantly higher during the COVID-19 period (p<0.001) with a median time to death of 35 days compared with 62 days pre-COVID-19. DISCUSSION: This study provides a unique perspective on the impact that the global pandemic had on decompensated cirrhosis admissions. The findings of increased early mortality and readmissions, and higher AD scores on ICU admission, highlight the need to maintain resourcing for high-level hepatology care and follow-up, in spite of other disease pressures.

Translocator protein is a marker of activated microglia in rodent models but not human neurodegenerative diseases.

Microglial activation plays central roles in neuroinflammatory and neurodegenerative diseases. Positron emission tomography (PET) targeting 18 kDa Translocator Protein (TSPO) is widely used for localising inflammation in vivo, but its quantitative interpretation remains uncertain. We show that TSPO expression increases in activated microglia in mouse brain disease models but does not change in a non-human primate disease model or in common neurodegenerative and neuroinflammatory human diseases. We describe genetic divergence in the TSPO gene promoter, consistent with the hypothesis that the increase in TSPO expression in activated myeloid cells depends on the transcription factor AP1 and is unique to a subset of rodent species within the Muroidea superfamily. Finally, we identify LCP2 and TFEC as potential markers of microglial activation in humans. These data emphasise that TSPO expression in human myeloid cells is related to different phenomena than in mice, and that TSPO-PET signals in humans reflect the density of inflammatory cells rather than activation state.

Longitudinal study of stool-associated microbial taxa in sibling pairs with and without autism spectrum disorder.

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental disorder influenced by both genetic and environmental factors. Recently, gut dysbiosis has emerged as a powerful contributor to ASD symptoms. In this study, we recruited over 100 age-matched sibling pairs (between 2 and 8 years old) where one had an Autism ASD diagnosis and the other was developing typically (TD) (432 samples total). We collected stool samples over four weeks, tracked over 100 lifestyle and dietary variables, and surveyed behavior measures related to ASD symptoms. We identified 117 amplicon sequencing variants (ASVs) that were significantly different in abundance between sibling pairs across all three timepoints, 11 of which were supported by at least two contrast methods. We additionally identified dietary and lifestyle variables that differ significantly between cohorts, and further linked those variables to the ASVs they statistically relate to. Overall, dietary and lifestyle features were explanatory of ASD phenotype using logistic regression, however, global compositional microbiome features were not. Leveraging our longitudinal behavior questionnaires, we additionally identified 11 ASVs associated with changes in reported anxiety over time within and across all individuals. Lastly, we find that overall microbiome composition (beta-diversity) is associated with specific ASD-related behavioral characteristics.

Microbial succession and dynamics in meromictic Mono Lake, California.

Mono Lake is a closed-basin, hypersaline, alkaline lake located in Eastern Sierra Nevada, California, that is dominated by microbial life. This unique ecosystem offers a natural laboratory for probing microbial community responses to environmental change. In 2017, a heavy snowpack and subsequent runoff led Mono Lake to transition from annually mixed (monomictic) to indefinitely stratified (meromictic). We followed microbial succession during this limnological shift, establishing a two-year (2017-2018) water-column time series of geochemical and microbiological data. Following meromictic conditions, anoxia persisted below the chemocline and reduced compounds such as sulfide and ammonium increased in concentration from near 0 to ~400 and ~150 µM, respectively, throughout 2018. We observed significant microbial succession, with trends varying by water depth. In the epilimnion (above the chemocline), aerobic heterotrophs were displaced by phototrophic genera when a large bloom of cyanobacteria appeared in fall 2018. Bacteria in the hypolimnion (below the chemocline) had a delayed, but systematic, response reflecting colonization by sediment "seed bank" communities. Phototrophic sulfide-oxidizing bacteria appeared first in summer 2017, followed by microbes associated with anaerobic fermentation in spring 2018, and eventually sulfate-reducing taxa by fall 2018. This slow shift indicated that multi-year meromixis was required to establish a sulfate-reducing community in Mono Lake, although sulfide oxidizers thrive throughout mixing regimes. The abundant green alga Picocystis remained the dominant primary producer during the meromixis event, abundant throughout the water column including in the hypolimnion despite the absence of light and prevalence of sulfide. Our study adds to the growing literature describing microbial resistance and resilience during lake mixing events related to climatic events and environmental change.