Formation and function of ceramide-enriched membrane platforms with CD38 during M₁-receptor stimulation in bovine coronary arterial myocytes

Abstract

signaling by the production of cyclic ADP-ribose (cADPR), but the mechanisms by which the agonists activate this enzyme remain unclear. The present study tested a hypothesis that a special lipid-raft (LR) form, ceramide-enriched lipid platform, contributes to CD38 activation to produce cADPR in response to muscarinic type 1 (M 1) receptor stimulation in bovine coronary arterial myocytes (CAMs). By confocal microscopic analysis, oxotremorine (Oxo), an M1 receptor agonist, was found to increase LR clustering on the membrane with the formation of a complex of CD38 and LR components such as GM1, acid sphingomyelinase (ASMase), and ceramide, a typical ceramide-enriched macrodomain. At 80 M, Oxo increased LR clustering by 78.8%, which was abolished by LR disruptors, methyl-␤-cyclodextrin (MCD), or filipin. With the use of a fluorescence resonance energy transfer (FRET) technique, 15.5 Ϯ 1.9% energy transfer rate (vs. 5.3 Ϯ 0.9% of control) between CD38 and LR component, ganglioside M1 was detected, further confirming the proximity of both molecules. In the presence of MCD or filipin, there were no FRET signals detected. In floated detergent-resistant membrane fractions, CD38 significantly increased in LR fractions of CAMs treated by Oxo. Moreover, MCD or filipin attenuated Oxo-induced production of cADPR via CD38. Functionally, Oxo-induced intracellular Ca 2ϩ release and coronary artery constriction via cADPR were also blocked by LR disruption or ASMase inhibition. These results provide the first evidence that the formation of ceramide-enriched lipid macrodomains is crucial for Oxo-induced activation of CD38 to produce cADPR in CAMs, and these lipid macrodomains mediate transmembrane signaling of M1 receptor activation to produce second messenger cADPR.

Lysosome-dependent Ca2+ release response to Fas activation in coronary arterial myocytes through NAADP: evidence from CD38 gene knockouts

“…In regard to the possible mechanism by which FasL activates CD38 to generate NAADP, our recent studies have reported that CD38 could be aggregated in membrane raft clusters in coronary arterial smooth muscle cells and thereby result in the increased activity of CD38 as ADP-ribosyl cyclase for cADPR generation (22). Given that FasL is a potent stimulator for production of ceramide, a pivotal molecular for membrane raft clustering (40), it is possible that FasL stimulates ceramide production and consequently results in membrane raft clustering with CD38 aggregation and activation.…”

CD38 Mediates Angiotensin II–Induced Intracellular Ca2+ Release in Rat Pulmonary Arterial Smooth Muscle Cells

“…It has been suggested that NAADP binds directly to TPCs or to an accessory protein of the TPC complex to activate endolysosomal Ca 21 release (7). CD38 expression has been reported in some systemic arteries, including aorta and the coronary and renal arteries (8)(9)(10). Endogenous vasoconstrictors, such as norepinephrine, endothelin-1 (ET-1), and angiotensin II (Ang II), have been shown to activate the cyclase and catalase activities of CD38, contributing to the elevation of [Ca 21 ] i and vasoconstriction (11)(12)(13)(14)(15)(16).…”

Lipid Raft Redox Signaling: Molecular Mechanisms in Health and Disease

“…Among these agonists or death factors, Fas ligands were first reported to stimulate LR clustering with aggregation of gp91 phox and some other cytosolic subunits, which lead to the activation of NADPH oxidase in ECs (191,444). Such LR NADPH oxidase clusters or complexes produce ROS and thereby mediate transmembrane signaling from death receptors to intracellular effectors or targets such as NO, ryanodine receptors, vav and other molecules (188,428,431,444).…”