Defining the Independence of the Liver Circadian Clock.

Mammals rely on a network of circadian clocks to control daily systemic metabolism and physiology. The central pacemaker in the suprachiasmatic nucleus (SCN) is considered hierarchically dominant over peripheral clocks, whose degree of independence, or tissue-level autonomy, has never been ascertained in vivo. Using arrhythmic Bmal1-null mice, we generated animals with reconstituted circadian expression of BMAL1 exclusively in the liver (Liver-RE). High-throughput transcriptomics and metabolomics show that the liver has independent circadian functions specific for metabolic processes such as the NAD+ salvage pathway and glycogen turnover. However, although BMAL1 occupies chromatin at most genomic targets in Liver-RE mice, circadian expression is restricted to ∼10% of normally rhythmic transcripts. Finally, rhythmic clock gene expression is lost in Liver-RE mice under constant darkness. Hence, full circadian function in the liver depends on signals emanating from other clocks, and light contributes to tissue-autonomous clock function.

Long-Chain Acylcholines Link Butyrylcholinesterase to Regulation of Non-neuronal Cholinergic Signaling.

Acylcholines are comprised of an acyl chain esterified to a choline moiety; acetylcholine is the best-characterized member of this class, functioning as a neurotransmitter in the central and peripheral nervous systems as well as an inhibitor of cytokine production by macrophages and other innate immune cells. Acylcholines are metabolized by a class of cholinesterases, including acetylcholinesterase (a specific regulator of acetylcholine levels) and butyrylcholinesterase (BChE, an enigmatic enzyme whose function has not been resolved by genetic knockout models). BChE provides reserve capacity to hydrolyze acetylcholine, but its importance is arguable given acetylcholinesterase is the most catalytically efficient enzyme characterized to date. While known to be substrates of BChE in vitro, endogenous production of long-chain acylcholines is a recent discovery enabled by untargeted metabolomics. Compared to acetylcholine, long-chain acylcholines show greater stability in circulation with homeostatic levels-dictated by synthesis and clearance-suggested to impact cholinergic receptor sensitivity of acetylcholine with varying levels of antagonism. Acylcholines then provide a link between BChE and non-neuronal acetylcholine signaling, filling a gap in understanding around how imbalances between acylcholines and BChE could modulate inflammatory disease, such as the "cytokine storm" identified in severe COVID-19. Areas for further research, development, and clinical testing are outlined.

Macrophages redirect phagocytosis by non-professional phagocytes and influence inflammation.

Professional phagocytes (such as macrophages) and non-professional phagocytes (such as epithelial cells) clear billions of apoptotic cells and particles on a daily basis. Although professional and non-professional macrophages reside in proximity in most tissues, whether they communicate with each other during cell clearance, and how this might affect inflammation, is not known. Here we show that macrophages, through the release of a soluble growth factor and microvesicles, alter the type of particles engulfed by non-professional phagocytes and influence their inflammatory response. During phagocytosis of apoptotic cells or in response to inflammation-associated cytokines, macrophages released insulin-like growth factor 1 (IGF-1). The binding of IGF-1 to its receptor on non-professional phagocytes redirected their phagocytosis, such that uptake of larger apoptotic cells was reduced whereas engulfment of microvesicles was increased. IGF-1 did not alter engulfment by macrophages. Macrophages also released microvesicles, whose uptake by epithelial cells was enhanced by IGF-1 and led to decreased inflammatory responses by epithelial cells. Consistent with these observations, deletion of IGF-1 receptor in airway epithelial cells led to exacerbated lung inflammation after allergen exposure. These genetic and functional studies reveal that IGF-1- and microvesicle-dependent communication between macrophages and epithelial cells can critically influence the magnitude of tissue inflammation in vivo.

Unraveling the functional role of the orphan solute carrier, SLC22A24 in the transport of steroid conjugates through metabolomic and genome-wide association studies.

Variation in steroid hormone levels has wide implications for health and disease. The genes encoding the proteins involved in steroid disposition represent key determinants of interindividual variation in steroid levels and ultimately, their effects. Beginning with metabolomic data from genome-wide association studies (GWAS), we observed that genetic variants in the orphan transporter, SLC22A24 were significantly associated with levels of androsterone glucuronide and etiocholanolone glucuronide (sentinel SNPs p-value <1x10-30). In cells over-expressing human or various mammalian orthologs of SLC22A24, we showed that steroid conjugates and bile acids were substrates of the transporter. Phylogenetic, genomic, and transcriptomic analyses suggested that SLC22A24 has a specialized role in the kidney and appears to function in the reabsorption of organic anions, and in particular, anionic steroids. Phenome-wide analysis showed that functional variants of SLC22A24 are associated with human disease such as cardiovascular diseases and acne, which have been linked to dysregulated steroid metabolism. Collectively, these functional genomic studies reveal a previously uncharacterized protein involved in steroid homeostasis, opening up new possibilities for SLC22A24 as a pharmacological target for regulating steroid levels.

Metabolomic studies identify changes in transmethylation and polyamine metabolism in a brain-specific mouse model of tuberous sclerosis complex.

Tuberous sclerosis complex (TSC) is an autosomal dominant neurodevelopmental disorder and the quintessential disorder of mechanistic Target of Rapamycin Complex 1 (mTORC1) dysregulation. Loss of either causative gene, TSC1 or TSC2, leads to constitutive mTORC1 kinase activation and a pathologically anabolic state of macromolecular biosynthesis. Little is known about the organ-specific metabolic reprogramming that occurs in TSC-affected organs. Using a mouse model of TSC in which Tsc2 is disrupted in radial glial precursors and their neuronal and glial descendants, we performed an unbiased metabolomic analysis of hippocampi to identify Tsc2-dependent metabolic changes. Significant metabolic reprogramming was found in well-established pathways associated with mTORC1 activation, including redox homeostasis, glutamine/tricarboxylic acid cycle, pentose and nucleotide metabolism. Changes in two novel pathways were identified: transmethylation and polyamine metabolism. Changes in transmethylation included reduced methionine, cystathionine, S-adenosylmethionine (SAM-the major methyl donor), reduced SAM/S-adenosylhomocysteine ratio (cellular methylation potential), and elevated betaine, an alternative methyl donor. These changes were associated with alterations in SAM-dependent methylation pathways and expression of the enzymes methionine adenosyltransferase 2A and cystathionine beta synthase. We also found increased levels of the polyamine putrescine due to increased activity of ornithine decarboxylase, the rate-determining enzyme in polyamine synthesis. Treatment of Tsc2+/- mice with the ornithine decarboxylase inhibitor α-difluoromethylornithine, to reduce putrescine synthesis dose-dependently reduced hippocampal astrogliosis. These data establish roles for SAM-dependent methylation reactions and polyamine metabolism in TSC neuropathology. Importantly, both pathways are amenable to nutritional or pharmacologic therapy.

Phagosome maturation: going through the acid test.

Phagosome maturation is the process by which internalized particles (such as bacteria and apoptotic cells) are trafficked into a series of increasingly acidified membrane-bound structures, leading to particle degradation. The characterization of the phagosomal proteome and studies in model organisms and mammals have led to the identification of numerous candidate proteins that cooperate to control the maturation of phagosomes containing different particles. A subset of these candidate proteins makes up the first pathway to be identified for the maturation of apoptotic cell-containing phagosomes. This suggests that a machinery that is distinct from receptor-mediated endocytosis is used in phagosome maturation.

Unexpected link between an antibiotic, pannexin channels and apoptosis.

Plasma membrane pannexin 1 channels (PANX1) release nucleotide find-me signals from apoptotic cells to attract phagocytes. Here we show that the quinolone antibiotic trovafloxacin is a novel PANX1 inhibitor, by using a small-molecule screen. Although quinolones are widely used to treat bacterial infections, some quinolones have unexplained side effects, including deaths among children. PANX1 is a direct target of trovafloxacin at drug concentrations seen in human plasma, and its inhibition led to dysregulated fragmentation of apoptotic cells. Genetic loss of PANX1 phenocopied trovafloxacin effects, revealing a non-redundant role for pannexin channels in regulating cellular disassembly during apoptosis. Increase in drug-resistant bacteria worldwide and the dearth of new antibiotics is a major human health challenge. Comparing different quinolone antibiotics suggests that certain structural features may contribute to PANX1 blockade. These data identify a novel linkage between an antibiotic, pannexin channels and cellular integrity, and suggest that re-engineering certain quinolones might help develop newer antibacterials.

Serum metabolites associate with lipid phenotypes among Bogalusa Heart Study participants.

BACKGROUND AND AIMS: Dyslipidemia has been identified as a major risk factor for cardiovascular disease. We aimed to identify metabolites and metabolite modules showing novel association with lipids among Bogalusa Heart Study (BHS) participants using untargeted metabolomics. METHODS AND RESULTS: Untargeted ultrahigh performance liquid chromatography-tandem mass spectroscopy was used to quantify serum metabolites of 1 243 BHS participants (816 whites and 427 African-Americans). The association of single metabolites with lipids was assessed using multiple linear regression models to adjust for covariables. Weighted correlation network analysis was utilized to identify modules of co-abundant metabolites and examine their covariable adjusted correlations with lipids. All analyses were conducted according to race and using Bonferroni-corrected α-thresholds to determine statistical significance. Thirteen metabolites with known biochemical identities showing novel association achieved Bonferroni-significance, p < 1.04 × 10-5, and showed consistent effect directions in both whites and African-Americans. Twelve were from lipid sub-pathways including fatty acid metabolism (arachidonoylcholine, dihomo-linolenoyl-choline, docosahexaenoylcholine, linoleoylcholine, oleoylcholine, palmitoylcholine, and stearoylcholine), monohydroxy fatty acids (2-hydroxybehenate, 2-hydroxypalmitate, and 2-hydroxystearate), and lysoplasmalogens [1-(1-enyl-oleoyl)-GPE (P-18:1) and 1-(1-enyl-stearoyl)-GPE (P-18:0)]. The gamma-glutamylglutamine, peptide from the gamma-glutamyl amino acid sub-pathway, were also identified. In addition, four metabolite modules achieved Bonferroni-significance, p < 1.39 × 10-3, in both whites and African-Americans. These four modules were largely comprised of metabolites from lipid sub-pathways, with one module comprised of metabolites which were not identified in the single metabolite analyses. CONCLUSION: The current study identified 13 metabolites and 4 metabolite modules showing novel association with lipids, providing new insights into the physiological mechanisms regulating lipid levels.

Novel associations between blood metabolites and kidney function among Bogalusa Heart Study and Multi-Ethnic Study of Atherosclerosis participants.

INTRODUCTION: Chronic kidney disease (CKD) is a major public health challenge given its high global prevalence and associated risks of cardiovascular disease and progression to end stage renal disease. Although it is known that numerous metabolic changes occur in CKD patients, identifying novel metabolite associations with kidney function may enhance our understanding of the physiologic pathways relating to CKD. OBJECTIVES: The objective of this study was to elucidate novel metabolite associations with kidney function among participants of two community-based cohorts with carefully ascertained metabolomics, kidney function, and covariate data. METHODS: Untargeted ultrahigh-performance liquid chromatography-tandem mass spectrometry was used to detect and quantify blood metabolites. We used multivariate adjusted linear regression to examine associations between single metabolites and creatinine-based estimated glomerular filtration rate (eGFRcr) among 1243 Bogalusa Heart Study (BHS) participants (median eGFRcr: 94.4, 5th-95th percentile: 66.0-119.6 mL/min/1.73 m2). Replication, determined by statistical significance and consistent effect direction, was tested using gold standard measured glomerular filtration rate (mGFR) among 260 Multi-Ethnic Study of Atherosclerosis (MESA) participants (median mGFR: 72.0, 5th-95th percentile: 43.5-105.0 mL/min/1.73 m2). All analyses used Bonferroni-corrected alpha thresholds. RESULTS: Fifty-one novel metabolite associations with kidney function were identified, including 12 from previously unrelated sub-pathways: N6-carboxymethyllysine, gulonate, quinolinate, gamma-CEHC-glucuronide, retinol, methylmalonate, 3-hydroxy-3-methylglutarate, 3-aminoisobutyrate, N-methylpipecolate, hydroquinone sulfate, and glycine conjugates of C10H12O2 and C10H14O2(1). Significant metabolites were generally inversely associated with kidney function and smaller in mass-to-charge ratio than non-significant metabolites. CONCLUSION: The 51 novel metabolites identified may serve as early, clinically relevant, kidney function biomarkers.

Phosphatidylserine receptor BAI1 and apoptotic cells as new promoters of myoblast fusion.

Skeletal muscle arises from the fusion of precursor myoblasts into multinucleated myofibres. Although conserved transcription factors and signalling proteins involved in myogenesis have been identified, upstream regulators are less well understood. Here we report an unexpected discovery that the membrane protein BAI1, previously linked to recognition of apoptotic cells by phagocytes, promotes myoblast fusion. Endogenous BAI1 expression increased during myoblast fusion, and BAI1 overexpression enhanced myoblast fusion by means of signalling through ELMO/Dock180/Rac1 proteins. During myoblast fusion, a fraction of myoblasts within the population underwent apoptosis and exposed phosphatidylserine, an established ligand for BAI1 (ref. 3). Blocking apoptosis potently impaired myoblast fusion, and adding back apoptotic myoblasts restored fusion. Furthermore, primary human myoblasts could be induced to form myotubes by adding apoptotic myoblasts, even under normal growth conditions. Mechanistically, apoptotic cells did not directly fuse with the healthy myoblasts, rather the apoptotic cells induced a contact-dependent signalling with neighbours to promote fusion among the healthy myoblasts. In vivo, myofibres from Bai1(-/-) mice are smaller than those from wild-type littermates. Muscle regeneration after injury was also impaired in Bai1(-/-)mice, highlighting a role for BAI1 in mammalian myogenesis. Collectively, these data identify apoptotic cells as a new type of cue that induces signalling via the phosphatidylserine receptor BAI1 to promote fusion of healthy myoblasts, with important implications for muscle development and repair.

Genotype, B-vitamin status, and androgens affect spaceflight-induced ophthalmic changes.

Ophthalmic changes have occurred in a subset of astronauts on International Space Station missions. Visual deterioration is considered the greatest human health risk of spaceflight. Affected astronauts exhibit higher concentrations of 1-carbon metabolites (e.g., homocysteine) before flight. We hypothesized that genetic variations in 1-carbon metabolism genes contribute to susceptibility to ophthalmic changes in astronauts. We investigated 5 polymorphisms in the methionine synthase reductase (MTRR), methylenetetrahydrofolate reductase (MTHFR), serine hydroxymethyltransferase (SHMT), and cystathionine ß-synthase (CBS) genes and their association with ophthalmic changes after flight in 49 astronauts. The number of G alleles of MTRR 66 and C alleles of SHMT1 1420 both contributed to the odds of visual disturbances. Preflight dehydroepiandrosterone was positively associated with cotton wool spots, and serum testosterone response during flight was associated with refractive change. Block regression showed that B-vitamin status and genetics were significant predictors of many of the ophthalmic outcomes that we observed. In one example, genetics trended toward improving (P = 0.10) and B-vitamin status significantly improved (P < 0.001) the predictive model for refractive change after flight. We document an association between MTRR 66 and SHMT1 1420 polymorphisms and spaceflight-induced vision changes. This line of research could lead to therapeutic options for both space travelers and terrestrial patients.

Continued clearance of apoptotic cells critically depends on the phagocyte Ucp2 protein.

Rapid and efficient removal of apoptotic cells by phagocytes is important during development, tissue homeostasis and in immune responses. Efficient clearance depends on the capacity of a single phagocyte to ingest multiple apoptotic cells successively, and to process the corpse-derived cellular material. However, the factors that influence continued clearance by phagocytes are not known. Here we show that the mitochondrial membrane potential of the phagocyte critically controls engulfment capacity, with lower potential enhancing engulfment and vice versa. The mitochondrial membrane protein Ucp2, which acts to lower the mitochondrial membrane potential, was upregulated in phagocytes engulfing apoptotic cells. Loss of Ucp2 reduced phagocytic capacity, whereas Ucp2 overexpression enhanced engulfment. Mutational and pharmacological studies indicated a direct role for Ucp2-mediated mitochondrial function in phagocytosis. Macrophages from Ucp2-deficient mice were impaired in phagocytosis in vitro, and Ucp2-deficient mice showed profound in vivo defects in clearing dying cells in the thymus and testes. Collectively, these data indicate that mitochondrial membrane potential and Ucp2 are key molecular determinants of apoptotic cell clearance. As Ucp2 is linked to metabolic diseases and atherosclerosis, this newly discovered role for Ucp2 in apoptotic cell clearance has implications for the complex aetiology and pathogenesis of these diseases.

The vertebrate-specific Kinesin-6, Kif20b, is required for normal cytokinesis of polarized cortical stem cells and cerebral cortex size.

Mammalian neuroepithelial stem cells divide using a polarized form of cytokinesis, which is not well understood. The cytokinetic furrow cleaves the cell by ingressing from basal to apical, forming the midbody at the apical membrane. The midbody mediates abscission by recruiting many factors, including the Kinesin-6 family member Kif20b. In developing embryos, Kif20b mRNA is most highly expressed in neural stem/progenitor cells. A loss-of-function mutant in Kif20b, magoo, was found in a forward genetic screen. magoo has a small cerebral cortex, with reduced production of progenitors and neurons, but preserved layering. In contrast to other microcephalic mouse mutants, mitosis and cleavage furrows of cortical stem cells appear normal in magoo. However, apical midbodies show changes in number, shape and positioning relative to the apical membrane. Interestingly, the disruption of abscission does not appear to result in binucleate cells, but in apoptosis. Thus, Kif20b is required for proper midbody organization and abscission in polarized cortical stem cells and has a crucial role in the regulation of cerebral cortex growth.

Consumption of Walnuts in Combination with Other Whole Foods Produces Physiologic, Metabolic, and Gene Expression Changes in Obese C57BL/6J High-Fat-Fed Male Mice.

BACKGROUND: Although a reductionist approach has sought to understand the roles of individual nutrients and biochemicals in foods, it has become apparent that there can be differences when studying food components in isolation or within the natural matrix of a whole food. OBJECTIVE: The objective of this study was to determine the ability of whole-food intake to modulate the development of obesity and other metabolic dysfunction in mice fed a high-fat (HF), Western-style obesogenic diet. To test the hypothesis that an n-3 (ω-3) polyunsaturated fatty acid-rich food could synergize with other, largely polyphenol-rich foods by producing greater reductions in metabolic disease conditions, the intake of English walnuts was evaluated in combination with 9 other whole foods. METHODS: Eight-week-old male C57Bl/6J mice were fed low-fat (LF; 10% fat) and HF control diets, along with an HF diet with 8.6% (wt:wt) added walnuts for 9 wk. The HF control diet contained 46% fat with added sucrose (10.9%, wt:wt) and cholesterol (1%, wt:wt); the added sucrose and cholesterol were not present in the LF diet. Other groups were provided the walnut diet with a second whole food-raspberries, apples, cranberries, tart cherries, broccoli sprouts, olive oil, soy protein, or green tea. All of the energy-containing whole foods were added at an energy level equivalent to 1.5 servings/d. Body weights, food intake, and glucose tolerance were determined. Postmortem, serum lipids and inflammatory markers, hepatic fat, gene expression, and the relative concentrations of 594 biochemicals were measured. RESULTS: The addition of walnuts with either raspberries, apples, or green tea reduced glucose area under the curve compared with the HF diet alone (-93%, -64%, and -54%, respectively, P < 0.05). Compared with HF-fed mice, mice fed walnuts with either broccoli sprouts or green tea (-49% and -61%, respectively, P < 0.05) had reduced hepatic fat concentrations. There were differences in global gene expression patterns related to whole-food content, with many examples of differences in LF- and HF-fed mice, HF- and walnut-fed mice, and mice fed walnuts and walnuts plus other foods. The mean ± SEM increase in relative hepatic concentrations of the n-3 fatty acids α-linolenic acid, eicosapentanoic acid, and docosapentanoic acid in all walnut-fed groups was 124% ± 13%, 159% ± 11%, and 114% ± 10%, respectively (P < 0.0001), compared with LF- and HF-fed mice not consuming walnuts. CONCLUSIONS: In obese male mice, walnut consumption with an HF Western-style diet caused changes in hepatic fat concentrations, gene expression patterns, and fatty acid concentrations. The addition of a second whole food in combination with walnuts produced other changes in metabolite concentrations and gene expression patterns and other physiologic markers. Importantly, these substantial changes occurred in mice fed typical amounts of intake, representing only 1.5 servings each food/d.

Identification of two evolutionarily conserved genes regulating processing of engulfed apoptotic cells.

Engulfment of apoptotic cells occurs throughout life in multicellular organisms. Impaired apoptotic cell clearance (due to defective recognition, internalization or degradation) results in autoimmune disease. One fundamental challenge in understanding how defects in corpse removal translate into diseased states is the identification of critical components orchestrating the different stages of engulfment. Here we use genetic, cell biological and molecular studies in Caenorhabditis elegans and mammalian cells to identify SAND-1 and its partner CCZ-1 as new factors in corpse removal. In worms deficient in either sand-1 or ccz-1, apoptotic cells are internalized and the phagosomes recruit the small GTPase RAB-5 but fail to progress to the subsequent RAB-7(+) stage. The mammalian orthologues of SAND-1, namely Mon1a and Mon1b, were similarly required for phagosome maturation. Mechanistically, Mon1 interacts with GTP-bound Rab5, identifying Mon1 as a previously unrecognized Rab5 effector. Moreover, a Mon1-Ccz1 complex (but not either protein alone) could bind Rab7 and could also influence Rab7 activation, suggesting Mon1-Ccz1 as an important link in progression from the Rab5-positive stage to the Rab7-positive stage of phagosome maturation. Taken together, these data identify SAND-1 (Mon1) and CCZ-1 (Ccz1) as critical and evolutionarily conserved components regulating the processing of ingested apoptotic cell corpses.

Unexpected requirement for ELMO1 in clearance of apoptotic germ cells in vivo.

Apoptosis and the subsequent clearance of dying cells occurs throughout development and adult life in many tissues. Failure to promptly clear apoptotic cells has been linked to many diseases. ELMO1 is an evolutionarily conserved cytoplasmic engulfment protein that functions downstream of the phosphatidylserine receptor BAI1, and, along with DOCK1 and the GTPase RAC1, promotes internalization of the dying cells. Here we report the generation of ELMO1-deficient mice, which we found to be unexpectedly viable and grossly normal. However, they had a striking testicular pathology, with disrupted seminiferous epithelium, multinucleated giant cells, uncleared apoptotic germ cells and decreased sperm output. Subsequent in vitro and in vivo analyses revealed a crucial role for ELMO1 in the phagocytic clearance of apoptotic germ cells by Sertoli cells lining the seminiferous epithelium. The engulfment receptor BAI1 and RAC1 (upstream and downstream of ELMO1, respectively) were also important for Sertoli-cell-mediated engulfment. Collectively, these findings uncover a selective requirement for ELMO1 in Sertoli-cell-mediated removal of apoptotic germ cells and make a compelling case for a relationship between engulfment and tissue homeostasis in vivo.

Pannexin 1 channels mediate 'find-me' signal release and membrane permeability during apoptosis.

Apoptotic cells release 'find-me' signals at the earliest stages of death to recruit phagocytes. The nucleotides ATP and UTP represent one class of find-me signals, but their mechanism of release is not known. Here, we identify the plasma membrane channel pannexin 1 (PANX1) as a mediator of find-me signal/nucleotide release from apoptotic cells. Pharmacological inhibition and siRNA-mediated knockdown of PANX1 led to decreased nucleotide release and monocyte recruitment by apoptotic cells. Conversely, PANX1 overexpression enhanced nucleotide release from apoptotic cells and phagocyte recruitment. Patch-clamp recordings showed that PANX1 was basally inactive, and that induction of PANX1 currents occurred only during apoptosis. Mechanistically, PANX1 itself was a target of effector caspases (caspases 3 and 7), and a specific caspase-cleavage site within PANX1 was essential for PANX1 function during apoptosis. Expression of truncated PANX1 (at the putative caspase cleavage site) resulted in a constitutively open channel. PANX1 was also important for the 'selective' plasma membrane permeability of early apoptotic cells to specific dyes. Collectively, these data identify PANX1 as a plasma membrane channel mediating the regulated release of find-me signals and selective plasma membrane permeability during apoptosis, and a new mechanism of PANX1 activation by caspases.

Gender- and Age-Associated Differences in Serum Metabolite Profiles among Japanese Populations.

Serum metabolites can reflect the diffusion/export of biochemicals from various organs. They can serve as biomarkers related to diseases and therapeutic efficacy/toxicity. While studies in Caucasians suggested that subject gender and age can affect circulating metabolite profiles, the Japanese population has not been surveyed. Our objective was to delineate gender- and age-associated differences in serum metabolite profiles among Japanese populations. Using a mass spectrometry-based global metabolomics approach, 516 endogenous metabolites were detected in sera from Japanese individuals. The principal component analysis identified gender as the primary component, followed by age, suggesting that these two criteria were key contributors to variations in the dataset. Gender-associated differences were observed in 31 and 25% of metabolites in the young (age 25-35) and old (ages 55-65) populations, respectively, in redox homeostasis, and in steroid and purine nucleotide metabolism pathways. Age-associated differences were observed in 24 and 23% of metabolites in men and women, respectively. No pathway was commonly highlighted. Thus, gender and age impact on metabolite profiles in the Japanese population. Our results provide useful information to explore biomarkers for clinical applications in the Japanese population and to assess the applicability of known biomarkers identified in other populations to the Japanese population.

Metabolomics-Based Analysis of Banana and Pear Ingestion on Exercise Performance and Recovery.

Bananas and pears vary in sugar and phenolic profiles, and metabolomics was utilized to measure their influence on exercise performance and recovery. Male athletes (N = 20) cycled for 75 km while consuming water (WATER), bananas (BAN), or pears (PEAR) (0.6 g carbohydrate/kg each hour) in randomized order. UPLC-MS/MS and the library of purified standards maintained by Metabolon (Durham, NC) were used to analyze metabolite shifts in pre- and postexercise (0-h, 1.5-h, 21-h) blood samples. Performance times were 5.0% and 3.3% faster during BAN and PEAR versus WATER (P = 0.018 and P = 0.091, respectively), with reductions in cortisol, IL-10, and total leukocytes, and increases in blood glucose, insulin, and FRAP. Partial Least Square Discriminant Analysis (PLS-DA) showed a distinct separation between trials immediately (R(2)Y = 0.877, Q(2)Y = 0.457) and 1.5-h postexercise (R(2)Y = 0.773, Q(2)Y = 0.441). A total of 107 metabolites (primarily lipid-related) increased more than 2-fold during WATER, with a 48% and 52% reduction in magnitude during BAN and PEAR recovery (P < 0.001). Increases in metabolites unique to BAN and PEAR included fructose and fruit constituents, and sulfated phenolics that were related to elevated FRAP. These data indicate that BAN and PEAR ingestion improves 75-km cycling performance, attenuates fatty acid utilization and oxidation, and contributes unique phenolics that augment antioxidant capacity.

Phagocytic signaling: you can touch, but you can't eat.

The ability of phagocytes to discriminate between viable/healthy and apoptotic/foreign/abnormal cells is of fundamental importance; a recent study provides new molecular insights into the function of CD47-SIRP alpha signaling in this discrimination.