Glycosphingolipids of human thyroid

Characterization of Glycosphingolipids in the Human Parathyroid and Thyroid Glands

As part of a systematic investigation of the glycosphingolipids in human tissues, acid and non-acid glycosphingolipids from human thyroid and parathyroid glands were isolated and characterized with mass spectrometry and binding of carbohydrate-recognizing ligands, with a focus on complex compounds. The glycosphingolipid patterns of the human parathyroid and thyroid glands were very similar. The major acid glycosphingolipids were sulfatide and the gangliosides GM3, GD3, GD1a, GD1b, GT1b and Neu5Ac-neolactotetraosylceramide, and the major non-acid glycosphingolipids were globotriaosylceramide and globoside. We also found neolactotetra- and neolactohexaosylceramide, the x₂ glycosphingolipid, and complex glycosphingolipids with terminal blood group O and A determinants in both tissues. A glycosphingolipid with blood group Le^b determinant was identified in the thyroid gland, and the parathyroid sample had a glycosphingolipid with terminal blood group B determinant. Immunohistochemistry demonstrated the expression of blood group A antigens in both the thyroid and parathyroid glands. A weak cytoplasmatic expression of the GD1a ganglioside was present in the thyroid, while the parathyroid gland had a strong GD1a expression on the cell surface. Thus, the glycosylation of human thyroid and parathyroid glands is more complex than previously appreciated. Our findings provide a platform for further studies of alterations of cell surface glycosphingolipids in thyroid and parathyroid cancers.

Lipid autoreactivity in multiple sclerosis

Lipids comprise over 70% of the myelin sheath but have been largely underinvestigated as autoantigens in multiple sclerosis (MS). This paper cites evidence for the involvement of lipid autoreactivity in MS and details how self lipid cross-reactivity may also contribute to the development of type 1 diabetes and autoimmune thyroid disorders (both of which have been associated with MS). A further analysis of myelin chemistry suggests several mechanisms by which infection may contribute to etiology and trigger lipid autoreactivity via molecular mimicry. This analysis may aid the development of new therapies for autoimmune diseases.

The glycosphingolipids of human prostate tissue

Neutral glycolipids and gangliosides from surgical samples of benign human prostate tissue were analyzed by chemical, enzymatic and immunostaining procedures. The neutral glycolipids consisted of ceramide mono-, di-, tri- and tetrahexosides of the globo series plus paragloboside. The monosialoganglioside fraction contained GM3 and GM1 plus multiple species of monosialylated lactosamine-containing structures, including sialyl-alpha-2----3paragloboside plus at least two compounds having a non-reducing terminal sialyl alpha 2----6Gal linkage. The disialoganglioside fraction contained GD3 as the major component plus GD1a, GD2 and GD1b. GT1b was the major trisialoganglioside.

Sex-specific difference of the galabiosylceramide level in the glycosphingolipids of human thyroid

The glycosphingolipids of human thyroid were isolated and characterized by gas-liquid chromatography and sequential enzymic hydrolysis. The major purified components were identified as glucosyl- and galactosyl-ceramides, lactosyl- and galabiosylceramides, globotriaosyl- and globotetraosylceramides. The long-chain base analyses showed a high proportion of phytosphingosine in glycosylceramide and galabiosylceramide. Fatty acids in 22:0, 24:0, 24:1 prevailed, especially in the cerebroside fraction, with a significant content of alpha-hydroxylated species in galactosylceramide. Female thyroid had a very low content of galabiosylceramide and a higher content of glucosylceramide, as compared to male. No significant difference was found in the other neutral glycosphingolipids and gangliosides.

Isolation and partial characterization of the neutral glycosphingolipids and gangliosides of the human heart

The glycosphingolipids (GSL) of the human heart muscle have been isolated from total lipids by column and thin layer chromatography and their sugars and fatty acids analyzed by gas liquid chromatography. Hearts from traffic victims were obtained at autopsy between 12 and 16 hr after death and dissected into parts (left and right ventricular walls, intraventricular septum and papillary muscle). The neutral GSL content for those parts of the hearts of two males aged 22 and one female aged 14 ranged from about 90 to 160 nmoles/g wet weight. Trihexosyl ceramide and globoside were the most abundant neutral GSL. Total ganglioside content was about 50 nmoles/g wet weight, and the most abundant gangliosides were partially characterized as GM3 and GM1; other mono-, di- and trisialogangliosides were also present. Differences in the content and composition of neutral GSL and gangliosides between the heart and other human tissues are discussed. It is concluded that the patterns of these two GSL fractions of the heart are more complex than those of the extraneural human tissues.

Structure of neutral glycolipids in bovine thyroid tissue

Four asialo glycolipid fractions have been isolated from bovine thyroid glands. The structures were elucidated by partial hydrolysis, periodate oxidation, permethylation analysis and sequential enzymatic degradation studies. The following structures were identified: GL-1a glucosyl-beta-(1 leads to 1)ceramide; GL-1b galactosyl-beta-(1 leads to 1)ceramide: GL-2 galactosyl-beta-(1 leads to 4)glucosyl-beta-(1 leads to 1)ceramide: GL-3 galactosyl-alpha-(1 leads to 4)galactosyl-beta-(1 leads to 4)glucosyl-beta-(1 leads to 1)-ceramide; GL-4 N-acetylgalactosaminyl-beta-(1 leads to 3)galactosyl-alpha-(1 leads to 4)galactosyl-beta-(1 leads to 4)glucosyl-geta-(1 leads to 1)ceramide.

Changes in rat brain gangliosides following active avoidance conditioning

Brain gangliosides of rats trained in a conditioned avoidance Sidman task and undisturbed rats in their cages were studied. The (14C) acetate was injected intracerebrally seven days before the starting of 30 days training. Thirty-seven days after injection all rats were killed and ganglioside fractions were isolated from neocortex, hippocampus, brain stem, cerebellum and residual cerebral tissue of each one brain. Trained rats had higher levels of (14C)-labeled polysialogangliosides (G1, G2, G3) in hippocampus and neocortex than the controls. Regarding the rest of the brain areas, a significant increase of G2 in the residual cerebral tissue of the trained as compared with the controls was found. The results suggest that the sialic acid rich gangliosides of only certain parts of the brain are affected by the Sidman avoidance conditioning of the animals.

Lipid composition of lymphocyte plasma membrane from pig mesenteric lymph node

1. The lipid fraction of the plasma membrane of pig mesenteric lymph-node lymphocytes contained primarily (94%) neutral lipids and phospholipids in about equal weights. The remianing lipid comprised glycosphingolipids (1.8%), gangliosides (o.27%)and probably ceramides (1.3%). The major phospholipid was phosphatidylcholine (46% of the total), and mono- and tri-hexosylceramides accounted for 72% of the glycosphingolipids. Haematoside was distributed between the glycosphingolipid and ganglioside fractions. The major ganglioside was monosialoganglioside. About 90% of the sialic acid was N-glycollylated. 2. A comparision of the lipid composition of the plasma-membrane fraction with that of the initial lymph-node homogenate showed that the purified membrane contained increased proportions of phospholipids, especially sphingomyelin, glycosphingolipids and gangliosides. 3. Fatty acid analyses showed that the membrane phosphatidylcholine was rich in palmitic acid, that the sphingomeyelin and phosphatidylethanolamine were high in myristic acid and that the glycosphingolipids were rich in oleic acid.