Song-learning birds and humans share independently evolved similarities in brain pathways for vocal learning that are essential for song and speech and are not found in most other species. Comparisons of brain transcriptomes of song-learning birds and humans relative to vocal nonlearners identified convergent gene expression specializations in specific song and speech brain regions of avian vocal learners and humans. The strongest shared profiles relate bird motor and striatal song-learning nuclei, respectively, with human laryngeal motor cortex and parts of the striatum that control speech production and learning. Most of the associated genes function in motor control and brain connectivity. Thus, convergent behavior and neural connectivity for a complex trait are associated with convergent specialized expression of multiple genes.

Sepsis is a common cause of death, but outcomes in individual patients are difficult to predict. Elucidating the molecular processes that differ between sepsis patients who survive and those who die may permit more appropriate treatments to be deployed. We examined the clinical features, and the plasma metabolome and proteome of patients with and without community-acquired sepsis, upon their arrival at hospital emergency departments and 24 hours later. The metabolomes and proteomes of patients at hospital admittance who would die differed markedly from those who would survive. The different profiles of proteins and metabolites clustered into fatty acid transport and β-oxidation, gluconeogenesis and the citric acid cycle. They differed consistently among several sets of patients, and diverged more as death approached. In contrast, the metabolomes and proteomes of surviving patients with mild sepsis did not differ from survivors with severe sepsis or septic shock. An algorithm derived from clinical features together with measurements of seven metabolites predicted patient survival. This algorithm may help to guide the treatment of individual patients with sepsis.

Introduction The Alzheimer’s Disease Research Summits of 2012 and 2015 incorporated experts from academia, industry, and nonprofit organizations to develop new research directions to transform our understanding of Alzheimer’s disease (AD) and propel the development of critically needed therapies. In response to their recommendations, big data at multiple levels are being generated and integrated to study network failures in disease. We used metabolomics as a global biochemical approach to identify peripheral metabolic changes in AD patients and correlate them to cerebrospinal fluid pathology markers, imaging features, and cognitive performance. Methods Fasting serum samples from the Alzheimer’s Disease Neuroimaging Initiative (199 control, 356 mild cognitive impairment, and 175 AD participants) were analyzed using the AbsoluteIDQ-p180 kit. Performance was validated in blinded replicates, and values were medication adjusted. Results Multivariable-adjusted analyses showed that sphingomyelins and ether-containing phosphatidylcholines were altered in preclinical biomarker-defined AD stages, whereas acylcarnitines and several amines, including the branched-chain amino acid valine and α-aminoadipic acid, changed in symptomatic stages. Several of the analytes showed consistent associations in the Rotterdam, Erasmus Rucphen Family, and Indiana Memory and Aging Studies. Partial correlation networks constructed for Aβ1–42, tau, imaging, and cognitive changes provided initial biochemical insights for disease-related processes. Coexpression networks interconnected key metabolic effectors of disease. Discussion Metabolomics identified key disease-related metabolic changes and disease-progression-related changes. Defining metabolic changes during AD disease trajectory and its relationship to clinical phenotypes provides a powerful roadmap for drug and biomarker discovery.

Introduction: Increasing evidence suggests a role for the gut microbiome in central nervous system disorders and specific role for the gut-brain axis in neurodegeneration. Bile acids (BA), products of cholesterol metabolism and clearance, are produced in the liver and are further metabolized by gut bacteria. They have major regulatory and signaling functions and seem dysregulated in Alzheimer disease (AD). Methods: Serum levels of 15 primary and secondary BAs and their conjugated forms were measured in 1,464 subjects including 370 cognitively normal older adults (CN), 284 with early mild cognitive impairment (MCI), 505 with late MCI, and 305 AD cases enrolled in the AD Neuroimaging Initiative. We assessed associations of BA profiles including selected ratios with diagnosis, cognition, and AD-related genetic variants, adjusting for cofounders and multiple testing. Results: In AD compared to CN, we observed significantly lower serum concentrations of a primary BA (cholic acid CA) and increased levels of the bacterially produced, secondary BA, deoxycholic acid (DCA), and its glycine and taurine conjugated forms. An increased ratio of DCA:CA, which reflects 7α-dehydroxylation of CA by gut bacteria, strongly associated with cognitive decline, a finding replicated in serum and brain samples in the Rush Religious Orders and Memory and Aging Project. Several genetic variants in immune response related genes implicated in AD showed associations with BA profiles. Conclusion: We report for the first time an association between altered BA profile, genetic variants implicated in AD and cognitive changes in disease using a large multicenter study. These findings warrant further investigation of gut dysbiosis and possible role of gut liver brain axis in the pathogenesis of AD.

We have modified the biotin switch assay for protein S-nitrosothiols (SNOs), using resin-assisted capture (SNO-RAC). Compared with existing methodologies, SNO-RAC requires fewer steps, detects high-mass S-nitrosylated proteins more efficiently, and facilitates identification and quantification of S-nitrosylated sites by mass spectrometry. When combined with iTRAQ labeling, SNO-RAC revealed that intracellular proteins may undergo rapid denitrosylation on a global scale. This methodology is readily adapted to analyzing diverse cysteine-based protein modifications, including S-acylation.

As the lipidomics field continues to advance, self-evaluation within the community is critical. Here, we performed an interlaboratory comparison exercise for lipidomics using Standard Reference Material (SRM) 1950-Metabolites in Frozen Human Plasma, a commercially available reference material. The interlaboratory study comprised 31 diverse laboratories, with each laboratory using a different lipidomics workflow. A total of 1,527 unique lipids were measured across all laboratories and consensus location estimates and associated uncertainties were determined for 339 of these lipids measured at the sum composition level by five or more participating laboratories. These evaluated lipids detected in SRM 1950 serve as community-wide benchmarks for intra- and interlaboratory quality control and method validation. These analyses were performed using nonstandardized laboratory-independent workflows. The consensus locations were also compared with a previous examination of SRM 1950 by the LIPID MAPS consortium. While the central theme of the interlaboratory study was to provide values to help harmonize lipids, lipid mediators, and precursor measurements across the community, it was also initiated to stimulate a discussion regarding areas in need of improvement.

impact protein function and localization, largely via modulating membrane affi nity and protein stability (7)(8)(9). In contrast to the stable thioether linkage of S -prenylation, the thioester linkage of S -acylation confers a reversible and dynamic nature on this modifi cation, and many recent efforts are shedding light on how this modifi cation is regulated ( 8-11 ).There are a variety of methodologies to detect protein S -acylation/palmitoylation in intact cells. A well-established method involves incubating cells with 3 H-labeled palmitate, followed by autoradiography to visualize the degree of isotopic incorporation. However, this approach requires high levels of [ 3 H]palmitate (as many as several mCi per sample) and exposure times on the order of weeks ( 12, 13 ). More recent methods have cleverly circumvented these issues by using nonradioactive derivatives of palmitate, which can be enriched or detected via cycloaddition reactions ( "click chemistry") ( 14-17 ). Nonetheless, these "palmitate-centric" approaches are encumbered by i ) the need for radioactive or chemically modifi ed palmitate analogs; ii ) the likely bias for proteins that undergo rapid palmitate turnover versus proteins that are more stably palmitoylated; iii ) diffi culty in detecting individual S -acylated proteins or their specifi c sites of S -acylation; and iv ) the inability to detect proteins that are acylated with moieties other than palmitate (e.g., shorter, longer, or unsaturated lipid chains).Recently, a "cysteine-centric" approach to identify S -acylated proteins was introduced that uses the conversion of the protein thioester to a disulfi de-linked biotin ( 18, 19 ). This assay, known as acyl-biotin exchange (ABE), is readily Abstract Protein S -acylation is a major posttranslational modifi cation whereby a cysteine thiol is converted to a thioester. A prototype is S -palmitoylation (fatty acylation), in which a protein undergoes acylation with a hydrophobic 16 carbon lipid chain. Although this modifi cation is a well-recognized determinant of protein function and localization, current techniques to study cellular S -acylation are cumbersome and/or technically demanding. We recently described a simple and robust methodology to rapidly identify S -nitrosylation sites in proteins via resin-assisted capture (RAC) and provided an initial description of the applicability of the technique to S -acylated proteins (acyl-RAC). Here we expand on the acyl-RAC assay, coupled with mass spectrometry-based proteomics, to characterize both previously reported and novel sites of endogenous S -acylation. Acyl-RAC should therefore fi nd general applicability in studies of both global and individual protein S -acylation in mammalian cells. Supplementary key words acylation • H-Ras • lipid • palmitoylation • proteomicsProtein cysteine residues undergo a wide variety of chemical reactions owing to thiol nucleophilicity and redox reactivity. These reactions include S -nitrosylation ( 1, 2 ), S -prenylation ( 3, 4 ), and S -acylation ( 5, 6 ), wh...

Vendor-independent software tools for quantification of small molecules and metabolites are lacking, especially for targeted analysis workflows. Skyline is a freely available, open-source software tool for targeted quantitative mass spectrometry method development and data processing with a ten-year history supporting 6 major instrument vendors. Designed initially for proteomic analysis, we describe the expansion of Skyline to data for small molecule analysis, including selected reaction monitoring (SRM), high-resolution mass spectrometry (HRMS), and calibrated quantification. This fundamental expansion of Skyline from a peptide-sequence centric tool to a molecule-centric tool makes it agnostic to the source of the molecule while retaining Skyline features critical for workflows in both peptide and more general biomolecular research. The data visualization and interrogation features already available in Skyline -such as peak picking, chromatographic alignment, and transition selection -have been adapted to support small molecule data, including metabolomics. Herein, we explain the conceptual workflow for small molecule analysis using Skyline, demonstrate Skyline performance benchmarked against a comparable *