The molecular and metabolic program by which white adipocytes adapt to cool physiologic temperatures.

Although visceral adipocytes located within the body's central core are maintained at approximately 37°C, adipocytes within bone marrow, subcutaneous, and dermal depots are found primarily within the peripheral shell and generally exist at cooler temperatures. Responses of brown and beige/brite adipocytes to cold stress are well studied; however, comparatively little is known about mechanisms by which white adipocytes adapt to temperatures below 37°C. Here, we report that adaptation of cultured adipocytes to 31°C, the temperature at which distal marrow adipose tissues and subcutaneous adipose tissues often reside, increases anabolic and catabolic lipid metabolism, and elevates oxygen consumption.

Epigenetic Regulation of TLR4 in Diabetic Macrophages Modulates Immunometabolism and Wound Repair.

Macrophages are critical for the initiation and resolution of the inflammatory phase of wound healing. In diabetes, macrophages display a prolonged inflammatory phenotype preventing tissue repair. TLRs, particularly TLR4, have been shown to regulate myeloid-mediated inflammation in wounds.

Differential contribution of pyruvate carboxylation to anaplerosis and cataplerosis during non-gluconeogenic and gluconeogenic conditions in HepG2 cells.

Pyruvate carboxylase (PC) is an anaplerotic enzyme that supplies oxaloacetate to mitochondria enabling the maintenance of other metabolic intermediates consumed by cataplerosis. Using liquid chromatography mass spectrometry (LC-MS) to measure metabolic intermediates derived from uniformly labeled C-glucose or [3-C]l-lactate, we investigated the contribution of PC to anaplerosis and cataplerosis in the liver cell line HepG2. Suppression of PC expression by short hairpin RNA lowered incorporation of C glucose incorporation into tricarboxylic acid cycle intermediates, aspartate, glutamate and sugar derivatives, indicating impaired cataplerosis.

A role for long-chain acyl-CoA synthetase-4 (ACSL4) in diet-induced phospholipid remodeling and obesity-associated adipocyte dysfunction.

Objective: Regulation of fatty acid (FA) metabolism is central to adipocyte dysfunction during diet-induced obesity (DIO). Long-chain acyl-CoA synthetase-4 (ACSL4) has been hypothesized to modulate the metabolic fates of polyunsaturated FA (PUFA), including arachidonic acid (AA), but the in vivo actions of ACSL4 are unknown. The purpose of our studies was to determine the in vivo role of adipocyte ACSL4 in regulating obesity-associated adipocyte dysfunction.

Dimethyl Itaconate Is Not Metabolized into Itaconate Intracellularly.

Itaconic acid is an important metabolite produced by macrophages after stimulation with LPS. The role of itaconate in the inflammatory cascade is unclear. Here we used [C]itaconate and dimethyl [C]itaconate (DMI) to probe itaconate metabolism, and find that [C]DMI is not metabolized to itaconate.

N-Acetylgalactosamine-Targeted Delivery of Dendrimer-Doxorubicin Conjugates Influences Doxorubicin Cytotoxicity and Metabolic Profile in Hepatic Cancer Cells.

This study describes the development of targeted, doxorubicin (DOX)-loaded generation 5 (G5) polyamidoamine dendrimers able to achieve cell-specific DOX delivery and release into the cytoplasm of hepatic cancer cells. G5 is functionalized with poly(ethylene glycol) (PEG) brushes displaying N-acetylgalactosamine (NAcGal) ligands to target hepatic cancer cells. DOX is attached to G5 through one of two aromatic azo-linkages, L3 or L4, achieving either P1 ((NAcGal -PEGc) -G5-(L3-DOX) ) or P2 ((NAcGal -PEGc) -G5-(L4-DOX) ) conjugates.

Mass spectrometry analysis shows the biosynthetic pathways supported by pyruvate carboxylase in highly invasive breast cancer cells.

We recently showed that the anaplerotic enzyme pyruvate carboxylase (PC) is up-regulated in human breast cancer tissue and its expression is correlated with the late stages of breast cancer and tumor size [Phannasil et al., PloS One 10, e0129848, 2015]. In the current study we showed that PC enzyme activity is much higher in the highly invasive breast cancer cell line MDA-MB-231 than in less invasive breast cancer cell lines.

Monitoring cell secretions on microfluidic chips using solid-phase extraction with mass spectrometry.

Microfluidics is an enabling technology for both cell biology and chemical analysis. We combine these attributes with a microfluidic device for on-line solid-phase extraction (SPE) and mass spectrometry (MS) analysis of secreted metabolites from living cells in culture on the chip. The device was constructed with polydimethylsiloxane (PDMS) and contains a reversibly sealed chamber for perfusing cells.

Knockdown of ATP citrate lyase in pancreatic beta cells does not inhibit insulin secretion or glucose flux and implicates the acetoacetate pathway in insulin secretion.

Objective: Glucose-stimulated insulin secretion in pancreatic beta cells requires metabolic signals including the generation of glucose-derived short chain acyl-CoAs in the cytosol from mitochondrially-derived metabolites. One concept of insulin secretion is that ATP citrate lyase generates short chain acyl-CoAs in the cytosol from mitochondrially-derived citrate. Of these, malonyl-CoA, is believed to be an important signal in insulin secretion.

Metabolomics Analysis Reveals that AICAR Affects Glycerolipid, Ceramide and Nucleotide Synthesis Pathways in INS-1 Cells.

AMPK regulates many metabolic pathways including fatty acid and glucose metabolism, both of which are closely associated with insulin secretion in pancreatic β-cells. Insulin secretion is regulated by metabolic coupling factors such as ATP/ADP ratio and other metabolites generated by the metabolism of nutrients such as glucose, fatty acid and amino acids. However, the connection between AMPK activation and insulin secretion in β-cells has not yet been fully elucidated at a metabolic level.

Increased glucose metabolism and glycerolipid formation by fatty acids and GPR40 receptor signaling underlies the fatty acid potentiation of insulin secretion.

Acute fatty acid (FA) exposure potentiates glucose-stimulated insulin secretion in β cells through metabolic and receptor-mediated effects. We assessed the effect of fatty acids on the dynamics of the metabolome in INS-1 cells following exposure to [U-(13)C]glucose to assess flux through metabolic pathways. Metabolite profiling showed a fatty acid-induced increase in long chain acyl-CoAs that were rapidly esterified with glucose-derived glycerol-3-phosphate to form lysophosphatidic acid, mono- and diacylglycerols, and other glycerolipids, some implicated in augmenting insulin secretion.

Serum cytokeratin 19 fragment in advanced lung cancer: could we eventually have a serum tumor marker?

Introduction: Lung cancer is one of the most lethal malignancies; however, no serum marker has been routinely recommended until now.

Methods: THIS IS A PROSPECTIVE CASE CONTROL STUDY INCLUDING TWO GROUPS OF PATIENTS: Group I-patients with advanced lung cancer and Group II-patients with benign lung disease as control. Serum cytokeratin 19 (CK19) fragment levels were measured at baseline by real-time polymerase chain reaction before first-line chemotherapy.

Profiling targets of the irreversible palmitoylation inhibitor 2-bromopalmitate.

2-Bromohexadecanoic acid, or 2-bromopalmitate, was introduced nearly 50 years ago as a nonselective inhibitor of lipid metabolism. More recently, 2-bromopalmitate re-emerged as a general inhibitor of protein S-palmitoylation. Here, we investigate the cellular targets of 2-bromopalmitate through the synthesis and application of click-enabled analogues.

Metabolome response to glucose in the β-cell line INS-1 832/13.

Glucose-stimulated insulin secretion (GSIS) from pancreatic β-cells is triggered by metabolism of the sugar to increase ATP/ADP ratio that blocks the KATP channel leading to membrane depolarization and insulin exocytosis. Other metabolic pathways believed to augment insulin secretion have yet to be fully elucidated. To study metabolic changes during GSIS, liquid chromatography with mass spectrometry was used to determine levels of 87 metabolites temporally following a change in glucose from 3 to 10 mM glucose and in response to increasing concentrations of glucose in the INS-1 832/13 β-cell line.

Elevated levels of fibrinogen-derived endogenous citrullinated peptides in synovial fluid of rheumatoid arthritis patients.

Introduction: Rheumatoid arthritis (RA) is an autoimmune disease characterized by inflammation of the joints and the presence of autoantibodies directed against proteins containing the non-standard arginine-derived amino acid citrulline. The protein fibrinogen, which has an essential role in blood clotting, is one of the most prominent citrullinated autoantigens in RA, particularly because it can be found in the inflamed tissue of affected joints. Here, we set out to analyze the presence of citrullinated endogenous peptides in the synovial fluid of RA and arthritic control patients.