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McCall, L.-I.

Publications and source records attributed to McCall, L.-I..

18 recordsLinked to original sources

The Everything Bagel Feature Finder: Ultra-fast automated feature finding for untargeted metabolomics

Metabolomics studies are increasingly being applied with hundreds to thousands, even tens of thousands of samples that demand rapid, automated data processing while maintaining analytical sensitivity or quantitative accuracy. A major computational bottleneck is feature finding, which is the transformation of LC-MS and LC-MS/MS data into a set of analyte signals aligned and quantified across samples. Feature finding can be computationally intensive and often requires manual iterative parameter optimization. To accelerate this process, we present the Everything Bagel (EB) feature finder, an ultra-fast automated feature finding tool that integrates feature detection, retention-time alignment, and gap filling designed for run-time and memory efficiency. We benchmarked EB against two automated feature finding methods on eight benchmarking datasets. Specifically, we evaluated these three feature finding methods by measuring spike-in standard detection coverage, dilution series quantification accuracy, and yeast 12C/13C credentialed features. In this evaluation, the EB feature finder achieved performance comparable to, and often exceeding, existing methods while requiring up to 150-fold lower CPU hours and up to 113-fold lower wall time. We further demonstrated the bioanalytical validity of EB by reanalyzing published datasets used for biomarker discovery and reproduced biologically significant features that matched the published findings using manually tuned feature finding settings. Taken along with the speed improvements, we anticipate EB will enhance the ability to automatically analyze datasets with thousands to tens of thousands of samples for the community.

bioinformatics↗

Systematic assessment of the impact of targeted selection methods and environment-mimicking culture conditions on fungal natural product libraries

Natural products are a rich source of bioactive molecules and undiscovered chemical scaffolds with significant potential for novel drug discovery. Among these, fungi are particularly promising, offering diverse metabolites and undiscovered structural motifs. Large, well-curated collections of crude extracts, or "libraries", are central to fungal natural product discovery, serving as starting material for bioassay-guided isolation of new compounds. However, the systematic influence of fungal selection strategies, culturing methods, and environmental factors on chemical diversity remains underexplored. In this study, we analyzed several large fungal libraries to assess how geographic origin, and phylogenetic classification shape fungal chemical profiles. We also evaluated whether culturing conditions that more closely mimic natural environments can enhance metabolite diversity. Our findings offer practical guidelines for optimizing fungal natural product library design, improving drug development efficiency and access to novel chemotypes for future drug discovery. Summary Figure O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=60 SRC="FIGDIR/small/709592v1_ufig1.gif" ALT="Figure 1"> View larger version (16K): org.highwire.dtl.DTLVardef@70a0e0org.highwire.dtl.DTLVardef@51f84eorg.highwire.dtl.DTLVardef@184dd90org.highwire.dtl.DTLVardef@1ee2813_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

Optimization of 13C stable isotope labeling for the study of tricarboxylic cycle intermediates in mouse models

The tricarboxylic acid cycle (TCA), also known as the Krebs Cycle or the citric acid cycle, is an essential metabolic pathway involved in energy production that is often impacted by disease, making it of key interest to identify effective, affordable, and simple ways to monitor the impact of disease on TCA metabolism. 13C-based stable isotope labeling is a useful technique to track pathway alterations in living hosts. However, infusion-based methodologies are slow and expensive despite achieving steady-state labeling. Bolus-based methods are cheaper, faster, and compatible with biohazardous models, but require optimization to achieve maximum labeling. Herein, we performed bolus-based stable isotope labeling experiments in mouse models to identify the optimal dosage amount, label administration length, fast length prior to label administration, 13C-labeled precursor, and route of administration for the TCA cycle in the esophagus, heart, kidney, liver, plasma, and proximal colon. 13C-glucose at a concentration of 4 mg/g administered via intraperitoneal injection followed by a 90 minute label incorporation period achieved the best overall TCA labeling. For most organs, a 3 hour fast prior to label administration improved labeling, but labeling in the heart was better with no fasting period, showcasing the need to optimize methodology on an organ-by-organ basis. We also identified that bolus administration of glucose provided little impact on metabolism compared to vehicle control. The experiments outlined here provide critical information for designing in vivo stable isotope labeling experiments for the study of the TCA cycle. HighlightsO_LIA 90 minute waiting period following label administration provides best labeling C_LIO_LILarger dosing provides better labeling with little impact on metabolism C_LIO_LIFasting prior to label administration led to worse labeling in heart tissue C_LIO_LIIntraperitoneal dosing provides better incorporation than oral dosing C_LIO_LI13C-glucose provides better label incorporation than 13C-lactate and 13C-pyruvate C_LI

biochemistry↗

Spatially-divergent metabolic impact of experimental toxoplasmosis: immunological and microbial correlates

Maladaptive host metabolic responses to infection are emerging as major determinants of infectious disease pathogenesis. However, the factors regulating these metabolic changes within tissues remain poorly understood. In this study, we used toxoplasmosis, as a prototypical example of a disease regulated by strong type I immune responses, to assess the relative roles of local parasite burden, local tissue inflammation and the microbiome in shaping local tissue metabolism during acute and chronic infection. Toxoplasmosis is a zoonotic disease caused by the parasite Toxoplasma gondii. This protozoan infects the small intestine and then disseminates to nearly every organ in the acute stage of infection, before establishing chronic infection in the skeletal muscle, cardiac muscle and brain. We compared metabolism in eleven sampling sites in C57BL/6 mice during the acute and chronic stage of T. gondii infection. Strikingly, significant metabolic changes were observed in the large intestine and colon during chronic infection, organs not associated with T. gondii persistence. Overall, major spatial mismatches were observed between metabolic perturbation and local parasite burden for both disease stages. In contrast, a stronger association with indicators of type I immune responses was observed, indicating a tighter relationship between metabolic perturbation and local immunity, than with local parasite burden. In addition, we observed significant changes in microbiota composition with infection, and candidate microbial origins for multiple metabolites impacted by infection. These findings highlight the metabolic consequences of toxoplasmosis across different organs, and their regulators. ImportanceInflammation is a major driver of tissue perturbation. However, the signals driving these changes on a tissue-intrinsic and molecular level are poorly understood. This study evaluated tissue-specific metabolic perturbations across eleven sampling sites following systemic murine infection with the parasite Toxoplasma gondii. Results revealed relationships between differential metabolite enrichment and variables including inflammatory signals, pathogen burden and commensal microbial communities. These data will inform hypotheses about the signals driving specific metabolic adaptation in acute and chronic protozoan infection, with broader implications for infection and inflammation in general.

microbiology↗

Rationally Minimizing Natural Product Libraries Using Mass Spectrometry

Natural product libraries are crucial to drug development, but large libraries drastically increase the time and cost during initial high throughput screens. Here, we developed a method that leverages liquid chromatography-tandem mass spectrometry spectral similarity to dramatically reduce library size, with minimal bioactive loss. This method offers a broadly applicable strategy for accelerated drug discovery with cost reductions, which enable implementation in resource-limited settings.

bioinformatics↗

SARS-CoV-2 infection unevenly impacts metabolism in the coronal periphery of the lungs

HighlightsO_LICOVID-19 significantly decreases amino acids, fatty acids, and most eicosanoids C_LIO_LISARS-CoV-2 preferentially localizes to central lung tissue C_LIO_LIMetabolic disturbance is highest in peripheral tissue, not central like viral load C_LIO_LISpatial metabolomics allows detection of metabolites not altered overall C_LI SARS-CoV-2, the virus responsible for COVID-19, is a highly contagious virus that can lead to hospitalization and death. COVID-19 is characterized by its involvement in the lungs, particularly the lower lobes. To improve patient outcomes and treatment options, a better understanding of how SARS-CoV-2 impacts the body, particularly the lower respiratory system, is required. In this study, we sought to understand the spatial impact of COVID-19 on the lungs of mice infected with mouse-adapted SARS2-N501YMA30. Overall, infection caused a decrease in fatty acids, amino acids, and most eicosanoids. When analyzed by segment, viral loads were highest in central lung tissue, while metabolic disturbance was highest in peripheral tissue. Infected peripheral lung tissue was characterized by lower levels of fatty acids and amino acids when compared to central lung tissue. This study highlights the spatial impacts of SARS-CoV-2 and helps explain why peripheral lung tissue is most damaged by COVID-19.

microbiology↗

Persistent biofluid small molecule alterations induced by Trypanosoma cruzi infection are not restored by antiparasitic treatment

Table of contents graphic O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=105 SRC="FIGDIR/small/543565v1_figu1.gif" ALT="Figure 1"> View larger version (25K): org.highwire.dtl.DTLVardef@10c3a0aorg.highwire.dtl.DTLVardef@1b69d6dorg.highwire.dtl.DTLVardef@199867org.highwire.dtl.DTLVardef@64b20b_HPS_FORMAT_FIGEXP M_FIG C_FIG Chagas Disease (CD), caused by Trypanosoma cruzi (T. cruzi) protozoa, is a complicated parasitic illness with inadequate medical measures for diagnosing infection and monitoring treatment success. To address this gap, we analyzed changes in the metabolome of T. cruzi-infected mice via liquid chromatography tandem mass spectrometry analysis of clinically-accessible biofluids: saliva, urine, and plasma. Urine was the most indicative of infection status, across mouse and parasite genotypes. Metabolites perturbed by infection in the urine include kynurenate, acylcarnitines, and threonylcarbamoyladenosine. Based on these results, we sought to implement urine as a tool for assessment of CD treatment success. Strikingly, it was found that mice with parasite clearance following benznidazole antiparasitic treatment had comparable overall urine metabolome to mice that failed to clear parasites. These results match with clinical trial data in which benznidazole treatment did not improve patient outcomes in late-stage disease. Overall, this study provides insights into new small molecule-based CD diagnostic methods and a new approach to assess functional treatment response.

microbiology↗

Spatial metabolomics reveals localized impact of influenza virus infection on the lung tissue metabolome

The influenza virus (IAV) is a major cause of respiratory disease, with significant infection increases in pandemic years. Vaccines are a mainstay of IAV prevention, but are complicated by consideration of IAVs vast strain diversity, manufacturing and vaccine uptake limitations. While antivirals may be used for treatment of IAV, they are most effective in early stages of the infection and several virus strains have become drug resistant. Therefore, there is a need for advances in IAV treatment, especially host-directed, personalized therapeutics.Given the spatial dynamics of IAV infection and the relationship between viral spatial distribution and disease severity, a spatial approach is necessary to expand our understanding of IAV pathogenesis. We used spatial metabolomics to address this issue. Spatial metabolomics combines liquid chromatography-tandem mass spectrometry of metabolites extracted from systematic organ sections, 3D models and computational techniques, to develop spatial models of metabolite location and their role in organ function and disease pathogenesis. In this project, we analyzed plasma and systematically sectioned lung tissue samples from uninfected or infected mice. Spatial mapping of sites of metabolic perturbations revealed significantly lower metabolic perturbation in the trachea compared to other lung tissue sites. Using random forest machine learning, we identified metabolites that responded differently in each lung position based on infection, including specific amino acids, lipids and lipid-like molecules, and nucleosides. These results support the implementation of spatial metabolomics to understand metabolic changes upon IAV infection and to identify candidate pathways to be targeted for IAV therapeutics. ImportanceThe influenza virus is a major health concern. Over 1 billion people become infected annually despite the wide distribution of vaccines, and antiviral agents are insufficient to address current clinical needs. In this study, we used spatial metabolomics to understand changes in the lung and plasma metabolome of mice infected with influenza A virus, compared to uninfected controls. We determined metabolites altered by infection in specific lung tissue sites and distinguished metabolites perturbed by infection between lung tissue and plasma samples. Our findings highlight the importance of a spatial approach to understanding the intersection between lung metabolome, viral infection and disease severity. Ultimately, this approach will expand our understanding of respiratory disease pathogenesis and guide the development of novel host-directed therapeutics.

microbiology↗

Optimized extraction method enables quantitative analysis of surface metabolite recovery for exposomics and behavioral studies

Workplace chemical exposures are a major source of occupational injury. Although over half of these are skin exposures, exposomics research often focuses on chemical levels in the air or in worker biofluids such as blood and urine. Until now, one limitation has been the lack of methods to quantitatively measure surface chemical transfer. Outside the realm of harmful chemicals, the small molecules we leave behind on surfaces can also reveal important aspects of human behavior. In this study, we developed a swab-based quantitative approach to determine small molecule concentrations across common surfaces. We demonstrate its utility using one drug, cyclobenzaprine, and two human-derived metabolites, carnitine and phenylacetylglutamine, on four common surfaces: linoleum flooring, plastified laboratory workbench, metal and Plexiglass. This approach enabled linear small molecule recovery and quantification of molecule abundance on workplace built environment surfaces. Overall, this method paves the way for future quantitative exposomics studies.

biochemistry↗

Identification of Leucinostatins from Ophiocordyceps sp. as Antiparasitic Agents Against Trypanosoma cruzi

Safe and effective treatments for Chagas disease, a potentially fatal parasitic infection associated with cardiac and gastrointestinal pathology and caused by the kinetoplastid parasite Trypanosoma cruzi, have yet to be developed. Benznidazole and nifurtimox, which are currently the only available drugs against T. cruzi, are associated with severe adverse effects and questionable efficacy in the late stage of the disease. Natural products have proven to be a rich source of new chemotypes for other infectious agents. We utilized a microscopy-based high-throughput phenotypic screen to identify inhibitors of T. cruzi from a library of natural product samples obtained from fungi procured through a Citizen Science Soil Collection Program (https://whatsinyourbackyard.org/), and the Great Lakes (USA) benthic environment. We identified five leucinostatins (A, B, F, NPDG C and NPDG D) as potent inhibitors of the intracellular amastigote form of T. cruzi. Leucinostatin B also showed in vivo efficacy in a mouse model of Chagas disease. Given prior reports that leucinostatins A and B have antiparasitic activity against the related kinetoplastid T. brucei, our findings suggest a potential cross-trypanocidal compound class and provide a platform for further chemical derivatization of a potent chemical scaffold against T. cruzi.

microbiology↗

The Core Human Fecal Metabolome

Summary ParagraphAmong the biomolecules at the center of human health and molecular biology is a system of molecules that defines the human phenotype known as the metabolome. Through an untargeted metabolomic analysis of fecal samples from human individuals from Africa and the Americas--the birthplace and the last continental expansion of our species, respectively--we present the characterization of the core human fecal metabolome. The majority of detected metabolite features were ubiquitous across populations, despite any geographic, dietary, or behavioral differences. Such shared metabolite features included hyocholic acid and cholesterol. However, any characterization of the core human fecal metabolome is insufficient without exploring the influence of industrialization. Here, we show chemical differences along an industrialization gradient, where the degree of industrialization correlates with metabolomic changes. We identified differential metabolite features like leucyl-leucine dipeptides and urobilin as major metabolic correlates of these behavioral shifts. Our results indicate that industrialization significantly influences the human fecal metabolome, but diverse human lifestyles and behavior still maintain a core human fecal metabolome. This study represents the first characterization of the core human fecal metabolome through untargeted analyses of populations along an industrialization gradient.

biochemistry↗

Alterations to the cardiac metabolome induced by chronic T. cruzi infection relate to the degree of cardiac pathology

Chronic Chagasic cardiomyopathy (CCC) is a Neglected Tropical Disease caused by the parasite Trypanosoma cruzi. The pathognomonic findings in symptomatic CCC patients and animal models includes diffuse cardiac fibrosis and inflammation with persistent parasite presence in the heart. This study investigated chemical alterations in different regions of the heart in relation to cardiac pathology indicators to better understand the long-term pathogenesis of this neglected disease. We used data from echocardiography, fibrosis biomarkers, and histopathological analysis to fully evaluate cardiac pathology. Metabolites isolated from the pericardial and endocardial sides of the right ventricular myocardium were analyzed by liquid chromatography tandem mass spectrometry. The endocardial sections contained significantly less cardiac inflammation and fibrosis than the pericardial sections. Cardiac levels of acylcarnitines, phosphocholines, and other metabolites were significantly disrupted in accordance with cardiac fibrosis, inflammation, and serum fibrosis biomarker levels. These findings have potential implications in treatment and monitoring for CCC patients.

microbiology↗

Spatial metabolomics identifies localized chemical changes in heart tissue during chronic cardiac Chagas disease

Chagas disease (CD) is one of thirteen neglected tropical diseases caused by the parasite Trypanosoma cruzi. CD is a vector-borne disease transmitted by triatomines but CD can also be transmitted through blood transfusions, organ transplants and congenital transmission. While endemic to Latin America, T. cruzi infects 7-8 million people worldwide and can induce severe cardiac symptoms including apical aneurysms, thromboembolisms and arrhythmias during the chronic stage of CD. However, these cardiac clinical manifestations and CD disease pathogenesis are not fully understood. Using spatial metabolomics (chemical cartography), we sought to understand the localized impact of infection on the cardiac metabolome of mice chronically infected with two divergent T. cruzi strains. Our data showed chemical differences in localized cardiac regions upon chronic T. cruzi infection, indicating that parasite infection changes the host metabolome at select sites in chronic CD. These sites were distinct from the sites of highest parasite burden. In addition, we identified acylcarnitines and phosphocholines as discriminatory chemical families within each heart region, comparing infected and uninfected samples. Overall, our study indicated overall and positional metabolic differences common to infection with different T. cruzi strains, and identified select infection-modulated pathways. These results provide further insight into CD pathogenesis and demonstrate the advantage of a spatial perspective to understand infectious disease tropism.Author Summary Chagas disease (CD) is a tropical disease caused by the parasite Trypanosoma cruzi. CD originated in South America; however, there are now 7-8 million people infected worldwide due to population movements. CD is transmitted through a triatomine vector, organ transplants, blood transfusions and congenital transmission. It occurs in two stages, an acute stage (usually asymptomatic) and the chronic stage. Chronic stage CD presents with severe cardiac symptoms such as heart failure, localized aneurysms and cardiomyopathy. Unfortunately, what causes severe cardiac symptoms in some individuals in chronic CD is not fully understood. Therefore, we used liquid chromatography-tandem mass spectrometry to analyze the heart tissue of chronically T. cruzi-infected and uninfected mice, to understand the impact of infection on the tissue metabolome. We identified discriminatory small molecules related to T. cruzi infection. We also determined that regions with the highest parasite burden are distinct from the regions with the largest changes in overall metabolite profile; these locations of high metabolic perturbation provide a molecular mechanism to why localized cardiac symptoms occur in CD. Overall, our work gives insight to chronic cardiac CD symptom development and shapes a framework for novel treatment and biomarker development.Competing Interest StatementThe authors have declared no competing interest.View Full Text

biochemistry↗

Metabolite profiling of experimental cutaneous leishmaniasis lesions demonstrates significant perturbations in tissue phospholipids

Each year 700,000 to 1.2 million new cases of cutaneous leishmaniasis (CL) are reported and yet CL remains one of thirteen diseases classified as neglected tropical diseases (NTDs). Leishmania major is one of several different species of that same genus that can cause CL. Current CL treatments are limited by adverse effects and rising resistance. Studying disease metabolism at the site of infection can lead to new drug targets. In this study, samples were collected from mice infected in the ear and footpad with L. major and analyzed by untargeted liquid chromatography-tandem mass spectrometry (LC-MS/MS). Significant differences in overall metabolite profiles were noted in the ear at the site of the lesion. Interestingly, lesion-adjacent, macroscopically healthy sites also showed alterations in specific metabolites, including select phosphocholines (PCs). Host-derived PCs in the lower m/z range (m/z 200-799) showed an increase with infection in the ear at the lesion site, while those in the higher m/z range (m/z 800-899) were decreased with infection at the lesion site. Overall, our results expanded our understanding of the mechanisms of CL pathogenesis through the host metabolism and may lead to new curative measures against infection with Leishmania. Author summaryCutaneous leishmaniasis (CL) is one of thirteen neglected tropical diseases in the world today. It is an infectious disease with a wide distribution spanning five continents, with increasing distribution expected due to climate change. CL manifests as skin lesions and ulcers that are disabling and stigmatized. With the current treatment options being limited, studying host-pathogen metabolism can uncover mechanisms of disease pathogenesis that may lead to new curative measures against infection. In this paper we used untargeted metabolomics to address molecular-level changes occurring in vivo in experimental skin lesions of Leishmania major. Distinct global metabolic profiles were observed. Total phosphocholines (PCs) and those in the lower m/z ranges were significantly higher at the site of the skin lesion in the ear. In addition, specific PCs as well as PCs of varied m/z ranges were also affected at healthy-appearing lesion-adjacent sites, indicating that infection-induced metabolic perturbations are not restricted to the lesion site. Ultimately, these results provide essential clues to the metabolic pathways affected by CL.

biochemistry↗

Feature-based Molecular Networking in the GNPS Analysis Environment

Molecular networking has become a key method used to visualize and annotate the chemical space in non-targeted mass spectrometry-based experiments. However, distinguishing isomeric compounds and quantitative interpretation are currently limited. Therefore, we created Feature-based Molecular Networking (FBMN) as a new analysis method in the Global Natural Products Social Molecular Networking (GNPS) infrastructure. FBMN leverages feature detection and alignment tools to enhance quantitative analyses and isomer distinction, including from ion-mobility spectrometry experiments, in molecular networks.

bioinformatics↗

Repository-scale Co- and Re-analysis of Tandem Mass Spectrometry Data

Metabolomics data are difficult to find and reuse, even in public repositories. We, therefore, developed the Reanalysis of Data User (ReDU) interface (https://redu.ucsd.edu/), a community- and data-driven approach that solves this problem at the repository scale. ReDU enables public data discovery and co- or re-analysis via uniformly formatted, publicly available MS/MS data and metadata in the Global Natural Product Social Molecular Networking Platform (GNPS), consistent with findable, accessible, interoperable, and reusable (FAIR) principles.1

bioinformatics↗

3D mapping of host-parasite-microbiome interactions reveals metabolic determinants of tissue tropism and disease tolerance in Chagas disease

Chagas disease (CD) is a parasitic infection caused by Trypanosoma cruzi protozoa. Over 8 million people worldwide are T. cruzi-positive, 20-30% of which will develop cardiomyopathy, megaoesophagus and/or megacolon. The mechanisms leading to gastrointestinal (GI) symptom development are however poorly understood. To address this issue, we systematically characterized the spatial impact of experimental T. cruzi infection on the microbiome and metabolome across the GI tract. The largest microbiota perturbations were observed in the proximal large intestine in both acute and chronic disease, with chronic-stage effects also observed in the cecum. Strikingly, metabolomic impact of acute-to-chronic stage transition differed depending on the organ, with persistent large-scale effects of infection primarily in the oesophagus and large intestine, providing a potential mechanism for GI pathology tropism in CD. Infection particularly affected acylcarnitine and lipid metabolism. Building on these observations, treatment of infected mice with carnitine-supplemented drinking water prevented acute-stage mortality with no changes in parasite burden. Overall, these results identified a new mechanism of disease tolerance in CD, with potential for the development of new therapeutic regimens. More broadly, these results highlight the potential of spatially-resolved metabolomic approaches to provide insight into disease pathogenesis, with translational applications for infectious disease drug development.

microbiology↗

Characterization of the workplace chemical exposome using untargeted LC-MS/MS: a case study

Western people now spend close to 90% of their time indoors, one-quarter of which occurs at their place of employment. As such, interactions between employees and the workplace built environment have significant potential impact on employee health and safety. However, the range of workers daily chemical exposures is still poorly understood. Likewise, the influence of workers themselves and of worker behavior on the chemical composition of the workplace is still unknown. In this case study, we used untargeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) to compare the chemical signatures of three different types of workplaces: scientific research buildings, office buildings, and one mixed-purpose building. Our results identified differential signatures of public building surfaces based on building purpose, sampling location and surface materials. Overall, these results are helping define the influence of human behavior on the workplace chemical environment and identify the chemical hazards to which people are exposed throughout their workday. HighlightsO_LIImplementation of untargeted liquid chromatography-tandem mass spectrometry to study workplace chemical exposures. C_LIO_LIShared chemical signatures were identified based on building purpose. C_LIO_LIDifferential chemical signatures were identified based on surface material and sampling location. C_LIO_LIAnnotated molecules include pharmaceuticals, illicit drugs, food chemicals, constituents of paints and stains, and cleaning products. C_LI

biochemistry↗