13C C16 Sphingomyelin is an isotopically enriched form of C16 sphingomyelin with carbon-13 occurring on the fatty acid portion. It is intended for use as an internal standard for the quantification of C16 sphingomyelin by GC- or LC-MS. C16 Sphingomyelin is a form of sphingomyelin containing palmitate (16:0) at the variable acylation position. It is the most common form of sphingomyelin found in eggs and is less abundant in the brain and in milk. C16 Sphingomyelin interacts with cholesterol in ordered lipid domains (lipid rafts). Sphingomyelinases remove phosphorylcholine from C16 sphingomyelin to produce C16ceramide. While ceramides commonly induce apoptosis, ceramides with different fatty acid chain lengths might direct distinct functions and, in some cases, reduce apoptosis.
C24 dihydroCeramide is a sphingolipid that has been found in the stratum corneum of human skin.[1] It is found in higher concentrations in female sebum compared to male sebum.[2] C24 dihydroCeramide levels positively correlate with cytotoxicity in CCRF-CEM, MOLT-4, COG-LL-317h, and COG-LL-332h T cell acute lymphoblastic leukemia (ALL) cell lines.[4] Levels of C24 dihydroceramide are increased by 149.49-fold in dihydroceramide desaturase 1 (DEGS1) knockdown UM-SCC-22A human head and neck squamous carcinoma cells in vitro.[4] C24 dihydroCeramide levels are also increased in INS-1 β-cells incubated with glucose and palmitate.[5]
Methylcarbamyl PAF C-16 is a stable analog of PAF C-16 with a half-life greater than 100 minutes in platelet poor plasma due to its resistance to degradation by PAF-AH. It is nearly equipotent with PAF C-16 in its ability to induce platelet aggregation both in isolated platelets and in platelet-rich plasma. In NRK-49 cells overexpressing the PAF receptor, both PAF C-16 and methylcarbamyl PAF C-16 cause the induction of c-myc and c-fos and the activation of mitogen-activated protein kinase. Methylcarbamyl PAF C-16 induces G1 phase cell cycle arrest, suggesting a potential role for PAF in the inhibition of oncogenic transformation.
C16 globotriaosylceramide is an endogenous sphingolipid found in mammalian cell membranes that is synthesized from C16 lactosylceramide . C16 globotriaosylceramide acts as a receptor for Shiga toxin in B cell-derived Raji cells and THP-1 monocytes. It accumulates in endothelial cells, pericytes, vascular smooth muscle cells, renal epithelial cells, dorsal ganglia neuronal cells, and myocardial cells in patients with Fabry disease. C16 globotriaosylceramide is also upregulated in plasma of patients with ovarian carcinoma compared to those with benign ovarian tumors or uterine fibroids.
PAF C-16 is a naturally occurring phospholipid produced upon stimulation through two distinct pathways known as the remodeling and 'de novo' pathways. It is a potent mediator of neutrophil migration and the production of reactive oxygen species and IL-6. Pathological processes involving PAF include necrotizing enterocolitis
C18 dihydroCeramide is a bioactive sphingolipid and precursor in the de novo synthesis of C18 ceramide that lacks the 4,5-trans double bond. [1] Increased C18 dihydroceramide lipid levels lead to increased triacylglycerol storage and autophagosome accumulation as well as upregulation of the fibrosis markers α-SMA and FGF2 in Chang and LX-2 liver cells. C18 dihydroCeramide is elevated in the plasma of pre-diabetics up to 9 years prior to the onset of type 2 diabetes. [2] It is also elevated in the skin of patients with lesional atopic dermatitis.[3]
C16 Phytoceramide (t18:0/16:0) is a phytoceramide, which is a family of sphingolipids found in the intestine, kidney, and extracellular spaces of the stratum corneum of the mammalian epidermis. C16 Phytoceramide (t18:0/16:0) is composed of a phytosphingosine backbone amine-linked to a C16 fatty acid chain. The levels of C16 phytoceramide (t18:0/16:0) increase following heat stress in S. cerevisiae. It has been used with other ceramides to create stratum corneum substitutes to study percutaneous penetration and psoriasis in vitro.
C16 Lactosylceramide is an endogenous bioactive sphingolipid. It forms membrane microdomains with Lyn kinase and the αi subunits of inhibitory G protein-coupled receptors (GPCRs), suggesting a role in cell signaling. Plasma levels of C16 lactosylceramide are elevated in insulin-resistant cattle. C16 Lactosylceramide is also upregulated in a mouse model of Niemann-Pick type C1 disease, a neurodegenerative cholesterol-sphingolipid lysosomal storage disorder.
2-O-methyl PAF C-16 is a synthetic analog of platelet-activating factor (PAF) featuring a methyl group attached via an ether linkage at the sn-2 position. While the specific biological activities of 2-O-methyl PAF C-16 remain undercharacterized, studies with its C-18 counterpart have demonstrated its ability to modulate various biological processes. These processes include reducing plasma membrane fluidity and hindering the invasiveness of tumor cells in embryonic chick hearts. Furthermore, in rat astrocytes, the C-18 analog prompts the release of significant amounts of nitric oxide (NO) through a mechanism that involves the activation of nitric oxide synthase (NOS).
ARN14988 is a potent inhibitor of acid ceramidase (IC50 = 12.8 nM for the human enzyme). It inhibits acid ceramidase activity and increases levels of C16dihydroceramide and C16ceramide in A375, G361, M14, MeWo, MNT-1, and SK-MEL-28 melanoma cells. ARN14988 also reduces growth of A375 and G361 melanoma cells (EC50s = 41.8 and 67.7 μM, respectively).