23 research outputs found
The Mechanism of Docosahexaenoic Acid-induced Phospholipase D Activation in Human Lymphocytes Involves Exclusion of the Enzyme from Lipid Rafts
Docosahexaenoic acid (DHA), an n-3 polyunsaturated fatty acid that inhibits T lymphocyte activation, has been shown to stimulate phospholipase D (PLD) activity in stimulated human peripheral blood mononuclear cells (PBMC). To elucidate the mechanisms underlying the DHA-induced PLD activation, we first characterized the PLD expression pattern of PBMC. We show that these cells express PLD1 and PLD2 at the protein and mRNA level and are devoid of oleate-dependent PLD activity. DHA enrichment of PBMC increased the DHA content of cell phospholipids, which was directly correlated with the extent of PLD activation. The DHA-induced PLD activation was independent of conventional protein kinase C but inhibited by brefeldin A, which suggests ADP-ribosylation factor (ARF)-dependent mechanism. Furthermore, DHA enrichment dose-dependently stimulated ARF translocation to cell membranes. Whereas 50% of the guanosine 5'-3-O-(thio)triphosphate plus ARF-dependent PLD activity and a substantial part of PLD1 protein were located to the detergent-insoluble membranes, so-called rafts, of non-enriched PBMC, DHA treatment strongly displaced them toward detergent-soluble membranes where ARF is present. Collectively, these results suggest that the exclusion of PLD1 from lipid rafts, due to their partial disorganization by DHA, and its relocalization in the vicinity of ARF, is responsible for its activation. This PLD activation might be responsible for the immunosuppressive effect of DHA because it is known to transmit antiproliferative signals in lymphoid cells
Primary unconstrained shoulder arthroplasty in patients with a fixed anterior glenohumeral dislocation. Journal of Bone and Joint Surgery
Radiographic comparison of flat-back and convex-back glenoid components in total shoulder arthroplasty
International audienc
Radiographic comparison of flat-back and convex-back glenoid components in total shoulder arthroplasty
International audienc
Radiographic comparison of two glenoid preparation techniques in total shoulder arthroplasty
Radiographic comparison of two glenoid preparation techniques in total shoulder arthroplasty
Silent coronaropathy: usefulness of dobutamine stress echocardiography in ischemic stroke
Phosphatidic acid-dependent activation of cAMP phosphodiesterase is necessary for Arg-Vasopressin induction of myogenesis
Arg8- Vasopressin (AVP) stimulates differentiation of L6 myoblasts (1) likely through activation of phospholipase D (PLD) and generation of phosphatidic acid (PA) (2). Conversely, high intracellular adenosine-3',5'-cyclic monophosphate (cAMP) levels and protein kinase A (PKA) activation inhibit myoblast differentiation (3). Intracellular cAMP level is not only regulated by activation of adenylyl cyclase but also by its hydrolysis due to phosphodiesterase (PDE) activity. We reported that PA can activate specific isoforms of type IV cAMP-phosphodiesterase (PDE4) in vitro (4). Here, we investigate whether AVP-induced differentiation of L6 myoblasts involves activation
of PDE4 isoforms by PA