Metabolomics: building on a century of biochemistry to guide human health

Medical diagnosis and treatment efficacy will improve significantly when a more personalized system for health assessment is implemented. This system will require diagnostics that provide sufficiently detailed information about the metabolic status of individuals such that assay results will be able to guide food, drug and lifestyle choices to maintain or improve distinct aspects of health without compromising others. Achieving this goal will use the new science of metabolomics – comprehensive metabolic profiling of individuals linked to the biological understanding of human integrative metabolism. Candidate technologies to accomplish this goal are largely available, yet they have not been brought into practice for this purpose. Metabolomic technologies must be sufficiently rapid, accurate and affordable to be routinely accessible to both healthy and acutely ill individuals. The use of metabolomic data to predict the health trajectories of individuals will require bioinformatic tools and quantitative reference databases. These databases containing metabolite profiles from the population must be built, stored and indexed according to metabolic and health status. Building and annotating these databases with the knowledge to predict how a specific metabolic pattern from an individual can be adjusted with diet, drugs and lifestyle to improve health represents a logical application of the biochemistry knowledge that the life sciences have produced over the past 100 years.     

Mechanism underlying silent cleanup of apoptotic cells

Apoptotic cells are cleared without an inflammatory response such as neutrophil infiltration. The mechanism underlying such silent cleanup of apoptotic cells has been intensively investigated in vitro for over a decade, and the concept that active suppression via IL-10, TGF-β, and nitric oxide enables such silent cleanup to occur has been emerging. However, because this concept has not been vigorously examined under a variety of experimental conditions in vivo, the possibility remains that a null response, in which neither cytokines nor nitric oxide is produced upon an encounter with apoptotic cells, is responsible for silent cleanup.     

Protective effects of MLIF analogs on cerebral ischemia-reperfusion injury in rats

The monocyte locomotion inhibitory factor (MLIF) is an anti-inflammatory oligopeptide produced by Entamoeba histolytica. Among its different effects, it inhibits locomotion of human monocytes, hence its original name. The carboxyl-terminal end group Cys-Asn-Ser is the pharmacophore of anti-inflammatory peptide Met-Gln-Cys-Asn-Ser. In this study, the N-terminal of Cys-Asn-Ser was modified. With the aim to enhance the antioxidant ability and penetrability of Cys-Asn-Ser, we designed and synthesized two tetrapeptides Tyr-Cys-Asn-Ser and His-Cys-Asn-Ser. The neuroprotective effects of Tyr-Cys-Asn-Ser and His-Cys-Asn-Ser on focal ischemia reperfusion were investigated, and their pharmacological activities compared with Cys-Asn-Ser were studied. In order to study the mechanism of neuroprotective effect of these peptides, the level of oxidative stress markers malondialdehyde (MDA) and superoxide dismutase (SOD) and pro-inflammatory factors interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and myeloperoxidase (MPO) were detected in brain tissue homogenate.     

Regulation of alternative splicing of Bcl-x by IL-6, GM-CSF and TPA

The splicing of many alternative exons in the precursor messenger RNA (pre-mRNA) is regulated by extracellular factors but the underlying molecular bases remain unclear. Here we report the differential regulation of Bcl-x pre-mRNA splicing by extracellular factors and their distinct requirements for pre-mRNA elements. In K562 leukemia cells, treatment with interleukin-6 (IL-6) or granulocyte-macrophage colony stimulating factor (GM-CSF) reduced the proportion of the Bcl-xL variant mRNA while treatment with 12-O-tetradecanoylphorbol 13-acetate (TPA) had no effect. In U251 glioma cells, however, TPA efficiently increased the Bcl-xL level. These regulations were also seen for a transfected splicing reporter mini-gene. Further analyses of deletion mutants indicate that nucleotides 1-176 of the downstream intron are required for the IL-6 effect, whereas additional nucleotides 177-284 are essential for the GM-CSF effect. As for the TPA effect, only nucleotides 1-76 are required in the downstream intron. Thus, IL-6, GM-CSF and TPA differentially regulate Bcl-x splicing and require specific intronic pre-mRNA sequences for their respective effects.     

Inflammatory cytokines activate p38 MAPK to induce osteoprotegerin synthesis by MG-63 cells

Inflammatory bone diseases are characterized by the presence of pro-inflammatory cytokines that regulate bone turnover. Osteoprotegerin (OPG) is a soluble osteoblast-derived protein that influences bone resorption by inhibiting osteoclast differentiation and activation. In the present study, we demonstrate that interleukin-1beta and tumor necrosis factor alpha induce OPG mRNA production and OPG secretion by osteoblast-like MG-63 cells. Maximum induction of OPG secretion by either cytokine requires activation of the p38 mitogen activated protein kinase (MAPK) pathway but neither the p42/p44 (ERK) nor the c-Jun N-terminal MAPK pathways. Induction of OPG mRNA by either cytokine is also p38 MAPK dependent. Taken together, these data indicate that cytokine-induced OPG gene expression and protein secretion are differentially regulated by specific MAP kinase signal transduction pathways.