Hemolysis of human erythrocytes is a new bioactivity of gangliosides.

Using sheep erythrocytes and liposomes, an inhibitory effect of gangliosides has been shown on the activation of the alternative pathway of complement. However, in studies using human erythrocytes, we found that gangliosides had hemolytic activity that was possibly mediated through activation of the alternative pathway. Pretreatment of human erythrocytes obtained from healthy volunteers or paroxysmal nocturnal hemoglobinuria (PNH) patients with a ganglioside mixture purified from human erythrocytes enhanced their susceptibility to homologous human complement, and resulted in dose-dependent hemolysis. The enhancement was more marked in PNH erythrocytes than control cells. Protease treatment of the ganglioside mixture did not change its hemolytic activity, but sialidase treatment abolished the activity. Among the major erythrocyte gangliosides, II3NeuAc-LacCer (GM3) was the most potent hemolytic agent. Gangliosides purified from bovine brain were also active, while neither nonsialylated glycosphingolipids, the ceramide moiety, or sialic acid alone were active. Sialic acid residues in the ganglioside molecules were essential to this activity, but the amount of the residue or the source of the gangliosides seemed not to be important. Several treatments inhibiting the alternative but not classical complement pathway markedly reduced the ganglioside hemolytic activity. This novel bioactivity of gangliosides was thus suggested to be mediated partly by activation of the alternative pathway.

Antiglycolipid autoantibody detected in the sera from systemic lupus erythematosus patients.

A high incidence of autoantibody against the neutral glycolipid "asialo GM1" was observed in sera from patients with systemic lupus erythematosus (SLE) with neurological disorders, using an immunoflocculation test. The sera from 14 out of 17 cases of SLE with neurological disorders showed antibody activity against asialo GM1 but not against the following glycolipids: asialo GM2 GM1, and galactocerebroside. In another 87 cases of SLE without any history of seizures, as well as 61 cases of other autoimmune diseases (rheumatoid arthritis, progressive systemic sclerosis, mixed connective tissue disease, etc.) and 20 cases of various neurological diseases (epilepsy, multiple sclerosis, etc.), no antibody could be detected. In general, the antibody titer was high several months, even years, before and/or after the seizure, though the titer was low at the time that patients showed definite neurological symptoms. Immunochemical characterization with Sephadex G-200 chromatogrphy and protein A-Sepharose CL-4B affinity column indicated that the antiasialo GM1 was probably an autoantibody belonging to the immunoglobulin G class. The above results suggest that this newly found autoantibody plays a role in the pathogenesis of neurological disorders accompanying SLE.

Altered expression of gangliosides in erythrocytes of paroxysmal nocturnal hemoglobinuria.

In paroxysmal nocturnal hemoglobinuria (PNH), impaired glycosyl-phosphatidylinositol (PI)-anchoring of membrane proteins such as decay-accelerating factor has been known to lead to increased susceptibility to complement. Moreover, abnormal expression of non-PI-anchoring glycoproteins such as C3b/C4b receptor (CR1) or glycophorin-alpha also has been shown in PNH. Therefore, we biochemically analyzed glycosphingolipids (GSL) as one of the membrane glycoconjugates of PNH erythrocytes. Erythrocytes of all seven PNH patients showed altered expression of sialosyl GSL (gangliosides) as compared with the control erythrocytes of healthy donors. Both a sialosylparagloboside (IV6NeuAc-nLc4Cer) among four major gangliosides and some minor gangliosides in normal erythrocytes variably disappeared in erythrocytes from the peripheral blood of PNH patients. As one of the possible mechanisms of altered expression of gangliosides in PNH erythrocytes, structural analysis suggested impaired sialylation of GSL. These results suggest not only the altered metabolism of gangliosides in PNH erythrocytes, but also a metabolic disorder of membrane glycoconjugates as a new feature of PNH.

Neosynthesis of neolacto- and novel ganglio-series gangliosides in a rat fibroblastic cell line brought about by transfection with the v-fes oncogene-containing Gardner-Arnstein strain feline sarcoma virus-DNA.

Transfection of retrovirus DNA from Gardner-Arnstein strain feline sarcoma virus containing v-fes oncogene into a rat fibroblastic cell line 3Y1 caused not only cell transformation but also a remarkable change in ganglioside expression. The ganglioside phenotype of the 3Y1 cells was characterized by the exclusive expression of GM3, along with a trace amount of "A" pathway-related gangliosides (GM2-GM1a-GD1a), whereas in the transfected transformant, 3Y1-GA, sialosylparagloboside containing N-acetyl neuraminic acid (NeuAc) and novel ganglio-series gangliosides (presumably GM1b and GD1 alpha) were expressed in addition to GM3. Thus, the Gardner-Arnstein strain feline sarcoma virus DNA transfection open two new ganglioside metabolic pathways, one leading to the synthesis of neolacto-series and the other to that of ganglio-series gangliosides. These results were in striking contrast to the cases of transfection with so-called "intranuclearly expressed" transforming genes, adenovirus E1, SV40-T, and myc, with which the same 3Y1 cells newly expressed GD3 with a concomitant decrease in precursor ganglioside GM3. The difference in underlying mechanisms of ganglioside metabolism shown by these two different types of oncogenes might reflect differences in the modes of action of the oncogenes and their biological activities.

Compensatory occurrence of IV2Fucalpha,II3NeuAcalpha-Gg4Cer and human fetal antigen Lc4Cer in small cell carcinomas of the human lung.

By means of a thin-layer chromatography immunostaining procedure involving a human monoclonal anti-Lc4Cer antibody, which was established by hybridizing murine myeloma cells and human lymphocytes from a cancer patient, Lc4Cer was proven to be a fetal antigen of human lung and to be a cancer-related antigen in small cell carcinomas of human lung, but not of other lung cancers, i.e., large cell carcinomas, adenocarcinomas, and squamous carcinomas. With the simultaneous detection of IV2Fuc alpha,II3NeuAc alpha-Gg4Cer with rabbit anti-IV2Fuc alpha,II3NeuAc alpha-Gg4Cer antiserum, the expression of Lc4Cer and IV2Fuc alpha,II3NeuAc alpha-Gg4Cer was found to be compensatory and, consequently, small cell lung carcinomas could be classified into Lc4Cer- and IV2Fuc alpha,II3NeuAc alpha-Gg4Cer-expressing types, L-SCLC and F-SCLC, respectively, which were detected in four and 27 of 31 patients' tissues and in one and three of four nude mouse-transplanted small cell lung carcinoma tissues, respectively. The compensatory expression of Lc4Cer and IV2Fuc alpha,II3NeuAc alpha-Gg4Cer in small cell carcinomas indicated that different metabolic pathways for glycosphingolipids were activated to give the distinct glycosphingolipid compositions in the two types of small cell lung carcinomas.

Glycosphingolipids of various human ovarian tumors: a significantly high expression of I3SO3GalCer and Lewis antigen in mucinous cystadenocarcinoma.

Among several human ovarian tumors, which include mucinous cystadenocarcinoma, serous cystadenocarcinoma, and clear cell adenocarcinoma, the mucinous cystadenocarcinoma showed a unique glycosphingolipid composition. In particular, more than 90% of the acidic glycosphingolipids in the mucinous cystadenocarcinoma is comprised of sulfolipids, which are hardly detected in normal ovary and are contained in concentrations of less than 40% in the other type of ovarian tumors. By means of negative ion fast atom bombardment mass spectrometry and gas liquid chromatography, the major sulfolipid in mucinous cystadenocarcinoma is confirmed to be I3SO3-GalCer with N-cerebronoyl phytosphingosine, that which contrasts with I3SO3-GalCer with N-nonhydroxy fatty acyl sphingosine as the major molecular species in the other ovarian cancers. In mucinous cystadenocarcinoma, galactosylceramide is found in the relatively high concentration and is also composed of N-cerebronoyl phytosphingosine. In addition, the concentrations of glycolipids with Le(a) and Le(b) antigenicities are significantly higher in mucinous cystadenocarcinoma than those in normal ovary and the other ovarian tumors.

Significant increase in the antibody to Gal alpha 1-3Gal structure in sera of patients with hepatocellular carcinoma after transcatheter arterial embolization.

Sera from the patients with chronic liver diseases and hepatocellular carcinoma (HCC) were tested for reactivity with neutral glycosphingolipids extracted from rabbit liver plasma membrane by enzyme-linked immunosorbent assay and thin-layer chromatography immunostaining. IgG class antibody to neutral glycosphingolipids was detected in 29.6% (8 of 27), 6.3% (1 of 16), 0% (0 of 8), 0% (0 of 25), and 6.9% (2 of 29) in the sera of patients with HCC, liver cirrhosis, autoimmune chronic active hepatitis, chronic hepatitis, and normal individuals, respectively. Using the serum positive for the antibody to neutral glycosphingolipids, the target antigen glycolipid was isolated. Negative ion fast atom bombardment mass spectrometry, exoglycosidases treatment, and permethylation analysis revealed that the main target antigen was IV3 alpha Gal-nLc4Cer. In enzyme-linked immunosorbent assay, IgG class antibody to IV3 alpha Gal-nLc4Cer was detected in 33.3% (9 of 27), 18.8% (3 of 16), 25% (2 of 8), 4% (1 of 25), and 6% (3 of 50) in the sera of patients with HCC, liver cirrhosis, autoimmune chronic active hepatitis, chronic hepatitis, and normal individuals, respectively. Of 9 HCC patients positive for the antibody, 6 had received transcatheter arterial embolization (TAE) therapy. Six of 10 patients who received TAE therapy had the antibody, whereas only 3 of 17 patients without TAE therapy had the antibody. This antibody may be a heterophile antibody, which recognizes Gal alpha 1-3Gal structure at the nonreducing terminal of the antigen. Since the occurrence of this antibody was closely related with TAE therapy, the necrosis of HCC induced by TAE therapy may stimulate the production of the antibody.

Tumor-associated mucin-type glycoprotein (CA54/61) defined by two monoclonal antibodies (MA54 and MA61) in ovarian cancers.

Two monoclonal antibodies, MA54 and MA61, were established by immunizing with culture medium supernatants of a lung adenocarcinoma cell line, and a double-determinant sandwich enzyme immunoassay system was developed by using these two monoclonal antibodies. The antigen recognized by this assay (CA54/61) was found to be often high in the sera of several cancers. The antigen recognized by MA54 (CA54) or MA61 (CA61) proved to be carbohydrate chain on a high molecular weight mucin-type glycoprotein, and CA54 has NeuAc alpha 2-6galactose in the terminal residue. CA54/61 was frequently found in the sera of ovarian cancer patients, the positive rate being 67, 64, 40, and 78% in serous, mucinous, endometrioid, and mesonephroid cancers, respectively, when the cut off value was set at mean + 4 SD. Since the positive rate of CA125, which is now the most widely used for the diagnosis of ovarian cancers, is rather low (approximately less than 50%) in mucinous cystoadenocarcinoma, CA54/61 will be of clinical value. In addition, CA61 was detected immunohistochemically in the fetal red blood cells with nuclei, indicating its oncodevelopmental character in nature.

Human uterine endometrial adenocarcinoma: characteristic acquirement of synthetic potentials for II3SO3-LacCer and ganglio series sulfoglycosphingolipids after transfer of the cancer cells to culture.

The acidic glycosphingolipid composition of human uterine endometrial adenocarcinoma was compared with those of normal uterine endometrium at the proliferative and the secretory phases. Upon chemical composition analysis, no significant transformation-associated change of these glycolipids was observed. However, when cancer cells from the patients with human uterine endometrial adenocarcinoma were transferred to culture, the composition of glycosphingolipids, particularly sulfoglycosphingolipids, was significantly altered after the 70th doubling time. I3SO3-GalCer, which was contained in the original tissues of uterine endometrial adenocarcinomas, disappeared completely from the cultured cells at the 70th doubling time, whereas II3SO3-LacCer and ganglio series sulfoglycosphingolipids, which were originally contained in a trace amount or not present at all in the cancer tissues, became the major components in the total acidic glycosphingolipids in the cultured cells. Also, among cell lines established from several gynecological cancers, which include uterine cervical squamous carcinoma, uterine endometrial adenocarcinoma, ovarian clear cell carcinoma, choriocarcinoma, uterine sarcoma, ovarian sarcoma, and vulvar melanoma, only those cells derived from uterine endometrial adenocarcinoma expressed II3SO3-LacCer and ganglio series sulfoglycosphingolipids and the synthetic activities of these sulfoglycolipids, indicating that uterine endometrial adenocarcinoma cells characteristically lose the sulfotransferase to GalCer and acquire the sulfotransferase to LacCer after being transferred to culture in vitro. Thus, the unique sulfoglycosphingolipids and sulfotransferase are useful markers for the characterization of uterine endometrial adenocarcinoma among human gynecological cancers.

Human monoclonal antibody (HMST-1) against lacto-series type 1 chain and expression of the chain in uterine endometrial cancers.

A human monoclonal antibody termed HMST-1 was produced by fusing lymphocytes from segments of human pelvic lymph nodes from an endometrial cancer patient with murine myeloma cells. The epitope recognized by HMST-1 was determined to be lacto-series type 1 chain-containing glycosphingolipid (Gal beta 1-3GlcNAc beta 1-3Gal beta 1-4Glc beta 1-1Cer) by isolating the antigen from endometrial cancer cell line SNG-II and analyzing with fast atom bombardment mass spectrometry, permethylation analysis, and exoglycosidase treatment. By the immunohistochemical avidin-biotin-peroxidase complex method, no normal endometrium and benign endometrial hyperplasia were stained with HMST-1, but HMST-1 reacted with about 35% of endometrial cancer cases. These facts indicate that the rate of expression of the antigen increases along with the course of malignancy in the endometrium. By sialidase treatment of the section, the positive rate increased to 57% in endometrial cancers and to 13% in normal endometrium, indicating that the antigen was masked with sialic acid and exposed by neuraminidase treatment. Immunohistochemistry also revealed that the antibody reacted with human fetal alimentary tract epithelium and mesothelium, indicating the oncodevelopmental nature of Gal beta 1-3GlcNAc beta 1-3Gal beta 1-4Glc beta 1-1Cer.

Ganglioside composition of rabbit thymus.

Gangliosides of rabbit thymus were extracted and analyzed by the ganglioside-mapping procedure developed previously. 1 g of thymus contained 205.1 nmol of lipid-bound sialic acid and the relative amounts of monosialoganglioside and di- and trisialoganglioside fractions were 76.6 and 23.3%, respectively, as based on lipid-bound sialic acid. No ganglioside containing N-acetylgalactosamine was detected in rabbit thymus. The predominant component was N-glycoloylneuraminosyl lacto-N-norhexaosyl ceramide, NeuGc(alpha, 2-3)Gal(beta, 1-4)GlcNAc(beta, 1-3)Gal(beta, 1-4)GlcNAc(beta, 1-3)Gal(beta, 1-4)Glc(beta, 1-1) ceramide, which constituted 38.4% of the total gangliosides. The other major gangliosides were N-glycoloylneuraminosyl lacto-N-neotetraosyl ceramide (31.3%), GD3 containing N-glycoloylneuraminic acid (11.8%), GM3 containing N-glycoloylneuraminic acid (10.6%) and GM3 containing N-acetylneuraminic acid (6.4%). C-18 sphingosine was the only long-chain base in all the gangliosides. Palmitic acid was the major fatty acid of thymus gangliosides and chromatographically more polar gangliosides contained higher proportions of palmitic acid: 46.3% in GM3, 47.5% in GD3, 60.2% in N-glycoloylneuraminosyl lacto-N-neotetraosyl ceramide and 89.6% in N-glycoloylneuraminosyl lacto-N-norhexaosyl ceramide.

Comparative study on ganglioside compositions of various rabbit tissues. Tissue-specificity in ganglioside molecular species of rabbit thymus.

Ganglioside compositions of various organs of rabbit (NIBS strain, male, 10 months old) were studied. Organs examined contained lipid-bound sialic acid at various concentrations but the amounts in extraneural tissues were less than one-fifth of that in brain. The gangliosides of various tissues were analyzed by ganglioside-mapping and by isolating individual components and determining their structures chemically or enzymatically. According to their backbone asialocarbohydrate chain, the major gangliosides of various tissues were classified into three groups: (1) lactose and ganglio-N-triose (lung, stomach, liver, intestine, kidney, testis and muscle); (2) ganglio-N-tetraose (brain); (3) lacto-N-neotetraose (thymus). 70% of all thymus gangliosides had a lacto-N-neotetraose backbone, which was tissue-specific. In marked contrast to the case in other tissues, in thymus N-glycoloylneuraminic acid constituted 90% of the total lipid-bound sialic acid, and all molecular species of thymus gangliosides contained N-glycoloylneuraminic acid. Palmitic acid was a major fatty acid of thymus gangliosides. Distinct differences were found in the fatty acid compositions of gangliosides with longer carbohydrate chains in various tissues.

A new chromatographic approach to the resolution of individual gangliosides. Ganglioside mapping.

1. Anion-exchange column chromatographies on DEAE-Sephadex, DEAE-Sepharose and QAE-Sephadex were tested for fractionation of ganglioside-molecular species. DEAE-Sepharose gave the best resolution, with good separation of mono-, di-, tri- and even tetrasialogangliosides. Even minor gangliosides could be resolved and detected by silica gel thin-layer chromatography of successive fractions of effluent from a DEAE-Sepharose column. In this two-step chromatographic system, the first step of elution from the column depends on differences in anionic charge and the second step of development on a silica gel plate depends on differences in polarity. With this ganglioside-mapping technique, at least 25 unidentified gangliosides were separated from bovine and human brains in addition to the well-known compounds, G7, GM3, GM2, GM1, GM1 (GlycNeu), GD2, GD3, GD1a, GD1a-GAN, GD1a(AcNeu, GlycNeu), GD1b, GT1a, GT1b and GQ. 2. The procedure was used to compare the gangliosides in human (3, 5 and 35 years old), bovine, cat, rat, rabbit, chicken and dog brains. The ganglioside profiles of human, cat, rat, rabbit and dog brains only differed in minor components. However, the gangliosides in chicken brain were unexpectedly complex, at least 30 minor gangliosides, including 15 monosialogangliosides being recognized. Gangliosides containing N-glycolylneuraminic acid (GDIa and GM1 type) were only found in bovine brain. The concentrations of tri- and tetrasialogangliosides in human brain were found to increase during maturation. 3. The long chain bases of each ganglioside fraction, in which the content of sialic acid was confirmed by measuring the ratio of sialic acid to stearic acid, were also analyzed as their aldehydes. The ratios of C-20 to C-18 sphingosine increased in the series from the mono- to tetrasialoganglioside fraction (0.216-1.777) in all animal brains tested.

Interaction between Clostridium botulinum neurotoxin and gangliosides.

The effect of gangliosides on Clostridium botulinum type A neurotoxin was examined in terms of detoxification. The molar concentrations of gangliosides necessary to detoxify 50% of 1 M Cl. botulinum neurotoxin were as follows: GM1, 2073; GM2, 2439; GM3, 6098; GD1a, 610; GD1b, 488; GT1a, 829; GT1b, 6 and GQ1b, 27. Inhibition by gangliosides of the neurotoxin binding to synaptosomes showed that GT1b was highly effective, but the others were not. Low-temperature treatment inhibited the detoxification of neurotoxin by GT1b and the binding of 125I-labelled neurotoxin to the synaptosome fraction. 125I-labelled neurotoxin was mixed with GM1 or GT1b and their molecular size was estimated by sucrose-density-gradient centrifugation. When 125I-labelled neurotoxin was incubated with GM1, a single radioactive peak having a sedimentation coefficient of 7.3 S appeared. When incubated with GT1b, however, 125I-labelled neurotoxin gave three peaks having sedimentation coefficients 14, 10 and 7.3 S, respectively. The present results indicated that the location and the number of sialic acids in ganglioside molecules are of significance in the detoxification and the binding of Cl. botulinum neurotoxin with ganglioside molecules.

Impaired spreading of surfactant phospholipids in the lungs of newborn rats with pulmonary hypoplasia as a model of congenital diaphragmatic hernia induced by nitrofen.

In order to clarify the pathological outcome of congenital diaphragmatic hernia (CDH), we devised an animal model of CDH by administration of 2,4-dichlorophenyl-p-nitrophenyl ether (nitrofen) to pregnant rats, and determined the level and distribution of lung surfactant using the monoclonal antibody toward sphingomyelin and disaturated phosphatidylcholine (disat-PC). In control rats, the concentration of disat-PC was found to increase greatly from 16 to 18 days of gestation. Intragastric administration of nitrofen to pregnant rats at day 9 of gestation resulted in CDH in 42.7% of fetuses delivered after 20 days of gestation. In nitrofen-treated fetuses, the concentration of disat-PC in the lungs was lower than those in control fetuses, and surfactant apoprotein SP-A was similarly reduced in nitrofen-treated fetuses. However, the concentration of disat-PC in nitrofen-treated fetuses was higher than that in control fetuses at 18 days of gestation, indicating a synthetic potential of surfactant in nitrofen-treated fetuses comparable to that at the late stage of normal gestation. Immunohistochemical study with the antibody revealed that surfactant phospholipid was mainly in the form of intracellular granules in nitrofen-treated fetuses, probably causing the hypoplastic lungs and then CDH, in contrast to the uniform distribution on the pulmonary alveolar surface in control fetuses.

Selective changes in gangliosides of human milk during lactation: a molecular indicator for the period of lactation.

Gangliosides of human milk from women at various periods of lactation were analyzed. GD3 in colostrum, particularly in the early period of lactation, was the major ganglioside, and the molar ratio of GM3 to GD3 was 0.2-0.3 in the milk at 2-6 days postpartum. In contrast, milk from women at 60-390 days postpartum contained GM3 as the major ganglioside and the molar ratio of GM3 to GD3 was more than 3. Milk at 8-40 days postpartum represented an intermediate stage in terms of the ratio of GM3 to GD3. The selective change in the molar ratio of gangliosides was observed as a phenomenon common to all human milk from different individuals at different periods of lactation, indicating that the periods of lactation can be defined on the basis of the ratio. Since glycolipids in human milk are preferentially localized in the milk fat globule membrane, which is derived from the plasma membrane of epithelial cells in the mammary gland, the changes in the ganglioside composition reported in this communication may reflect a qualitative change of the cells in the mammary gland.

Shedding of sulfated lipids into gastric fluid and inhibition of pancreatic DNase I by cholesterol sulfate in concert with bile acids.

Cholesterol sulfate (CS) and sulfatides in the epithelium of the digestive tract were found in the 1000xg supernatants of digestive fluid, particularly in gastric juices containing the duodenal contents and bile acids, there being 14-131 microg of CS and 3-54 microg of sulfatides per mg of protein in the fluid, respectively. CS and sulfatides dissolved in detergents including bile acids inactivated pancreatic trypsin to the same level as by DMSO-solubilized sulfated lipids at 37 degrees C. Similarly, pancreatic DNase I was inhibited by CS solubilized with DMSO or bile acids, but not by sulfatides or other membrane lipids at 37 degrees C. Both the sulfate group and the hydrophobic side chain of CS were indispensable structures for the inhibition of DNase I. Also, the optimum molar ratio of bile acids to CS was important for expression of the inhibitory activity of CS toward DNase I, it being 0.18 of the optimum ratio for sodium taurocholate, and the molar ratio of CS to DNase I for complete inhibition was 342:1. Thus, CS was shown to play a role as an epithelial inhibitor of DNase I in concert with bile acids.

Programmed expression of cholesterol sulfotransferase and transglutaminase during epidermal differentiation of murine skin development.

To clarify the role of cholesterol sulfate (CS) in the process of epidermal differentiation in vivo, we investigated the concentration of CS and the specific activities of cholesterol sulfotransferase (CST), cholesterol sulfate sulfatase (CS sulfatase) and epidermal transglutaminase (ETG) in murine skin in the pre- and postnatal periods. In the skin at day 14 of gestation, CS was not detected with TLC and the specific activities of all the enzymes were low. However, concomitant with the formation of the multilayered structure of the epidermis (at day 16), the specific activities of CST steeply increased. Although the insoluble CS sulfatase in the microsomal fraction remained at a relatively constant level, the soluble CST in the cytosol fraction showed a 6-fold increase from day 14 to day 16, and the activity decreased continuously in the following period, reaching one forty-sixth of the maximum level at 4-months-old mice. Reflected by the increase in activity, CS was detected in fetal skin at day 15, and the concentration in epidermis significantly increased during the gestation period, reaching maximum level at day 17. Furthermore, the changes in the concentration of cholesterol sulfate were identical with those of N-(O-linoleoyl)-omega-hydroxy fatty acyl sphingosine and its glucosyl derivative in the epidermis. On the other hand, the specific activity of ETG increased after birth. Thus, the activation of CST and ETG was shown to occur separately in association with the formation of the multilayered structure and thickening of the stratum corneum, respectively.

Cholesterol sulfate in rat tissues. Tissue distribution, developmental change and brain subcellular localization.

1. A reliable micromethod for the determination of the tissue level of cholesterol sulfate has been developed. Cholesterol sulfate was separated from the bulk of the free cholesterol by silica gel column chromatography, and the cholesterol sulfate fraction subjected to benzoylation. A small amount of contaminating free cholesterol and other lipids remaining in this fraction were converted to benzoyl esters while the cholesterol sulfate remained unreacted. The cholesterol sulfate was then separated from the benzoylated contaminants by a second silica gel chromatography column and subjected to solvolysis. The liberated cholesterol was determined by gas-liquid chromatography. 2. The cholesterol sulfate contents of the visceral organs of 43-day-old rats were determined. Every tissue examined contained small amounts of this sulfate. Kidney contained the highest concentration of cholesterol sulfate (250-300 mug/g dry tissue weight) followed by spleen (77 mug/g), adrenal gland (50-70 mug/g) and lung (50-57 mug/g). 3. In brain, cholesterol sulfate level rises sharply from 17 mug/g dry weight in 7-day-old rats to more than 50 mug/g in 15-day-olds, then it declines rapidly to 15 mug/g in the 40-day-olds and this level is maintained to adulthood. The developmental pattern in the liver resembles that in the brain, except that the peak is somewhat flatter with the highest value (60 mug/g dry weight) occurring in the 21-day-old animal. In contrast to the above two tissues, the level of kidney cholesterol sulfate increases steadily from 15 mug/g in 7-day-olds and reaches the adult level of approx. 200 mug/g in 50-day-olds. 4. The highest level of cholesterol sulfate in subcellular fractions of rat brain occurred in a fraction rich in nerve endings. The level here was 10 times higher than that in the mitochondrial fraction, which contained the lowest levels of this steroid sulfate.

Region-specific distribution of glycosphingolipids in the rabbit gastrointestinal tract: preferential enrichment of sulfoglycolipids in the mucosal regions exposed to acid.

Neutral and acidic glycosphingolipids from various regions of the rabbit gastrointestinal tract showed different but characteristic patterns. In particular, sulfatides were found to be present in high concentrations in the mucosal regions frequently exposed to gastric acid, such as the gastric mucosa and proximal intestinal mucosa (duodenum and jejunum). The majority of sulfatides in these tissues have been identified as GalCer-I3-sulfate, with alpha-hydroxy long-chain fatty acids, by chemical procedures including analysis by negative ion fast atom bombardment mass spectrometry. The concentrations of GalCer-I3-sulfate in the fundic mucosa, antral mucosa, duodenum, and jejunum were 394.0, 356.9, 829.3, and 378.1 nmol/g of dry weight, respectively. These concentrations exceed those in the kidney, which has been reported to contain the highest concentration of sulfatides, with the exception of the nervous system, also, especially in the fundic mucosa, gangliosides were drastically reduced, in contrast to sulfatides: the molar ratio of sulfatides to GM3, the major ganglioside, was about 11:1. In addition, in the acid hydrolysis experiment, using the same concentration of HCl as that present in the gastric juices, sulfatide proved to be much more resistant to acid than GM3. Therefore, the preferential distribution of sulfatides in the mucosal regions exposed to acid may be related to mucosal functions, such as acid secretion and protection from acidic environments.