ABSTRACT
Unsaturated fatty acids (UFA) are crucial for T-cell effector functions, as they can affect the growth, differentiation, survival, and function of T cells. Nonetheless, the mechanisms by which UFA affects T-cell behavior are ill-defined. Therefore, we analyzed the processing of oleic acid, a prominent UFA abundantly present in blood, adipocytes, and the fat pads surrounding lymph nodes, in CD4+ T cells. We found that exogenous oleic acid increases proliferation and enhances the calcium flux response upon CD3/CD28 activation. By using a variety of techniques, we found that the incorporation of oleic acid into membrane lipids, rather than regulation of cellular metabolism or TCR expression, is essential for its effects on CD4+ T cells. These results provide novel insights into the mechanism through which exogenous oleic acid enhances CD4+ T-cell function.
ABSTRACT
The recent crystal structures of CC chemokine receptors 2 and 9 (CCR2 and CCR9) have provided structural evidence for an allosteric, intracellular binding site. The high conservation of residues involved in this site suggests its presence in most chemokine receptors, including the close homologue CCR1. By using [3H]CCR2-RA-[ R], a high-affinity, CCR2 intracellular ligand, we report an intracellular binding site in CCR1, where this radioligand also binds with high affinity. In addition, we report the synthesis and biological characterization of a series of pyrrolone derivatives for CCR1 and CCR2, which allowed us to identify several high-affinity intracellular ligands, including selective and potential multitarget antagonists. Evaluation of selected compounds in a functional [35S]GTPγS assay revealed that they act as inverse agonists in CCR1, providing a new manner of pharmacological modulation. Thus, this intracellular binding site enables the design of selective and multitarget inhibitors as a novel therapeutic approach.
Subject(s)
Intracellular Space/drug effects , Intracellular Space/metabolism , Pyrroles/chemistry , Pyrroles/pharmacology , Receptors, CCR1/antagonists & inhibitors , Receptors, CCR2/antagonists & inhibitors , Allosteric Regulation/drug effects , Humans , Ligands , Molecular Docking Simulation , Protein Conformation , Pyrroles/chemical synthesis , Pyrroles/metabolism , Receptors, CCR1/chemistry , Receptors, CCR1/metabolism , Receptors, CCR2/chemistry , Receptors, CCR2/metabolism , Structure-Activity RelationshipABSTRACT
The lead content of the foil backing of 4 types of intraoral film commonly used by dentists was 69% to 85%. An environmental issue exists because these foils are typically thrown out with regular refuse, even though recycling programs exist. For a new adult patient, a full-mouth radiographic series would generate 11.2 g of waste lead; for a 6-month checkup, waste lead would only be produced if radiographs were required. In an experiment that simulated the acidic conditions that might be expected in a landfill site, 3.5-4.4 mg of lead was released during 17-hour incubation in dilute acetic acid. When distilled double-deionized water replaced the acid, 1.0-2.2 mg of lead was released by the same types of foils. Human health concerns also exist when dental assistants handle lead foil while developing radiographs and fail to change their gloves or wash their hands before handling instruments and dental paraphernalia used in the mouth. Although the amount of lead introduced into the oral cavity would be relatively small, the elimination of sources of lead exposure, especially for children, is important.
