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M J van Wijland

Publications and source records attributed to M J van Wijland.

14 recordsLinked to original sources
PubMed2001

Biliary anionic peptide fraction/calcium binding protein inhibits apolipoprotein A-I-mediated cholesterol efflux from cultured cells.

The ABC transporter ABCA1 has been implicated to control cholesterol efflux in a variety of cell types including macrophages, fibroblasts, and intestinal epithelial cells. In this study we have investigated whether the 6-kD protein anionic peptide fraction/calcium binding protein (APF/CBP) which has homology to apolipoprotein AI may regulate efflux mediated by lipoproteins. APF/CBP was purified from T-tube bile by ultracentrifugation and preparative reversed phase HPLC. Cholesterol efflux to a variety of acceptors was determined using cultured fibroblasts from controls and patients with Tangiers disease. APF/CBP (0.1 to 2.4 microg/ml) inhibited ApoA-1 (2 microg/ml) mediated cholesterol efflux from normal fibroblasts in a dose dependent manner but had no effect on aspecific efflux to methyl-beta-cyclodextrin or phosphatidylcholine liposomes. In ABCA1 deficient fibroblasts no effect of APF/CBP on efflux was seen. We conclude that APF/CBP specifically interferes with ApoA-I mediated cholesterol trafficking. We hypothesize that competitive binding to ABCA1 may explain the decreased ApoA-I mediated efflux from fibroblasts.

ATP Binding Cassette Transporter 1↗
PubMed1997

Regulation of mdr2 P-glycoprotein expression by bile salts.

The phosphatidyl translocating activity of the mdr2 P-glycoprotein (Pgp) in the canalicular membrane of the mouse hepatocyte is a rate-controlling step in the biliary secretion of phospholipid. Since bile salts also regulate the secretion of biliary lipids, we investigated the influence of the type of bile salt in the circulation on mdr2 Pgp expression and activity. Male mice were led a purified diet to which either 0.1% (w/w) cholate or 0.5% (w/w) ursodeoxycholate was added. This led to a near-complete replacement of the endogenous bile salt pool (mainly tauromuricholate) by taurocholate or tauroursodeoxycholate respectively. The phospholipid secretion capacity was then determined by infusion of increasing amounts of tauroursodeoxycholate. Cholate feeding resulted in a 55% increase in maximal phospholipid secretion compared with that in mice on the control diet. Northern blotting revealed that cholate feeding increased mdr2 Pgp mRNA levels by 42%. Feeding with ursodeoxycholate did not influence the maximum rate of phospholipid output or the mdr2 mRNA content. Female mice had a higher basal mdr2 Pgp mRNA level than male mice, and this was also correlated with a higher phospholipid secretion capacity. This could be explained by the 4-fold higher basal cholate content in the bile of female compared with male mice. Our results suggest that the type of bile salts in the circulation influences the expression of the mdr2 gene.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1995

Quantification of mucin in human gallbladder bile: a fast, specific, and reproducible method.

It is generally accepted that gallbladder mucin (GBM) plays an important role in the pathogenesis of cholesterol gallstone (ChG) disease. However, it remains unclear whether ChG patients have higher GBM concentrations than controls. Discrepant findings regarding biliary mucin concentrations may be due to methodological problems with the assays commonly used. The methods currently used to quantitate mucin in bile have not been systematically evaluated. To establish a reliable method for mucin quantification in bile, we evaluated three mucin assays: the classic Pearson-PAS (periodic acid Schiff) assay, a direct fluorometric assay, and a new PAS or fluorometric assay with the following modifications of the Pearson assay: preincubation of bile samples with TBS containing KSCN and sodium taurocholate and micellation of biliary lipids during gel chromatographic fractionation using 25 mM sodium taurocholate in the elution buffer. SDS-PAGE and monoclonal anti-human-GBM (GBM59) were used to identify mucin. Highly specific and reproducible mucin isolation was achieved with the modified method. We found considerable loss of mucin during the different purification steps in the Pearson method. The direct fluorometric assay showed unspecific fluorometric signal with low molecular constituents of bile. Our experiments showed that human-GBM can be accurately measured after a simple modified chromatographic fractionation followed by a PAS or fluorometric assay.

Bile↗
PubMed1994

Heterogeneity of human gallbladder mucin in bile.

1. Human gallbladder mucin has been implicated to play a role in gallstone disease. In spite of this fact relatively little is known about the structure of human gallbladder mucin. In this study we have investigated the possible heterogeneity of mucin. For this purpose polyclonal and monoclonal antibodies against gallbladder mucin were raised. All antibodies reacted primarily with carbohydrate antigenic determinants. With these antibodies the immunoreactivity of gallbladder mucin from 60 patients with cholesterol gallstones and 20 subjects without stones was screened. In addition, reactivity with several lectins was studied. 2. Considerable heterogeneity was found with both antibody and lectin typing, but there was no significant difference in heterogeneity between mucin from patients with gallstones and control subjects. Immunoblotting revealed that there was similarity between the reaction of the polyclonal antibody and the Helix pomatia agglutinin. All mucin preparations reacting with the polyclonal antibody also bound to Helix pomatia agglutinin. Nineteen of the 21 reacting mucins (90%) were from patients with blood group A (18 patients) or AB (one patient) and expression of A antigen could be demonstrated on the mucin of these patients. The resulting two reacting mucins were from patients with type O. However, expression of the blood group antigen could not account for the lack of reactivity of the mucin of other patients. The Helix pomatia agglutinin partially blocked the reactivity of the polyclonal antibody, whereas anti-A antibody did not show inhibition, indicating that more than only blood group A epitopes were recognized by this antibody. 3. We conclude that considerable patient to patient heterogeneity of human gallbladder mucin exists.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibody Specificity↗
PubMed1994

Heterogeneity of human biliary mucin: functional implications.

1. Human gallbladder mucin has been implicated as playing a role in the pathogenesis of gallstones. In previous studies no differences have been found in the content or composition of mucins derived from control bile or cholesterol gallstone bile. Until now, no differences were also found between these two groups of mucins with regard to their ability to cause cholesterol nucleation. In the accompanying paper we have reported that there is a strong heterogeneity of gallbladder mucins derived from individual patients (M. J. A. van Wijland, J. H. Klinkspoor, L. Th. de Wit, R. P. J. Oude Elferink, G. N. J. Tytgat and A. K. Groen, Clin Sci 1994; 86: 67-74). In the present study we further investigated a possible patient to patient heterogeneity of mucin by means of immunological and functional characterization of mucins isolated from hepatic bile of six different patients with gallstones. 2. Considerable heterogeneity was found. Two of the mucins barely reacted with a polyclonal anti-mucin antibody, whereas the other four mucins reacted very strongly. Lectin-binding studies indicated that the glycans of these two mucins expressed less D-N-acetylgalactosamine residues than the other four mucins. This was confirmed by analyses of the glycan compositions. These studies furthermore indicated that the glycans were of the O-linked type, contained alpha-D-N-acetylglucosamine and were fucosylated, sialylated and sulphated to different extents. Except for a strong heterogeneity in the sugar composition of the mucins, heterogeneity was also found in the biological activity of the mucins.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1988

Direct demonstration that the deficient oxidation of very long chain fatty acids in X-linked adrenoleukodystrophy is due to an impaired ability of peroxisomes to activate very long chain fatty acids.

A method was developed to prepare peroxisome-enriched fractions depleted of microsomes and mitochondria from cultured skin fibroblasts. The method consists of differential centrifugation of a postnuclear supernatant followed by density gradient centrifugation on a discontinuous Metrizamide gradient. The activity of hexacosanoyl-CoA synthetase was subsequently measured in postnuclear supernatants and peroxisome-enriched fractions prepared from cultured skin fibroblasts from control subjects and patients with X-linked adrenoleukodystrophy. Whereas the hexacosanoyl-CoA synthetase activity in postnuclear supernatants of X-linked adrenoleukodystrophy fibroblasts was only slightly decreased (77.8 +/- 4.4% of control (n = 15], enzyme activity was found to be much more markedly reduced in peroxisomal fractions isolated from the mutant fibroblasts (19.6 +/- 6.7% of control (n = 5]. This is a direct demonstration that the defect in X-linked adrenoleukodystrophy is at the level of a deficient ability of peroxisomes to activate very long chain fatty acids, as first suggested by Hashmi et al. [Hashmi, M., Stanley, W. and Singh, I. (1986) FEBS Lett. 86, 247-250].

Adrenoleukodystrophy↗
PubMed1988

A new peroxisomal disorder with enlarged peroxisomes and a specific deficiency of acyl-CoA oxidase (pseudo-neonatal adrenoleukodystrophy).

In the present paper two siblings are presented with clinical manifestations very similar to those of patients affected by neonatal adrenoleukodystrophy. In contrast to neonatal adrenoleukodystrophy patients, hepatic peroxisomes in these siblings were enlarged in size and not decreased in number. Accumulation of very-long-chain fatty acids (VLCFA) was associated with an isolated deficiency of the fatty acyl-CoA oxidase, the enzyme that catalyzes the first step of the peroxisomal beta-oxidation. Plasma levels of di- and trihydroxy-coprostanoic acid, phytanic acid, and pipecolic acid were normal; furthermore, acyl-CoA:dihydroxyacetone phosphate acyltransferase activity in cultured fibroblasts was also found to be normal. The clinical, biochemical, and cytochemical features found in these two siblings are compared with those seen in two other disorders characterized by the absence of a decreased number of hepatic peroxisomes and the presence of VLCFA: (1) pseudo-Zellweger syndrome (deficiency of peroxisomal thiolase activity) and (2) X-linked childhood adrenoleukodystrophy (deficiency of activation of lignoceric acid). Review of the different biochemical defects possible in very-long-chain fatty-acid oxidation reveals different clinical pictures of varying severity, depending on the level at which the biochemical defect occurs.

Acetyl-CoA C-Acetyltransferase↗
PubMed1987

Peroxisomal very long-chain fatty acid beta-oxidation in human skin fibroblasts: activity in Zellweger syndrome and other peroxisomal disorders.

Since very long-chain fatty acids with a chain length of 24 carbons or more are known to accumulate in tissues and body fluids from patients with the cerebrohepato-renal (Zellweger) syndrome, infantile Refsum disease, neonatal adrenoleukodystrophy and X-linked adrenoleukodystrophy, we studied very long-chain fatty acid oxidation in cultured skin fibroblasts from these patients. In this paper, we report that in accordance with earlier results the first step in the beta-oxidation of the very long-chain fatty acid lignoceric acid (C24:0) primarily occurs in peroxisomes in control human skin fibroblasts. Furthermore, it was found that peroxisomal lignoceric acid beta-oxidation was strongly deficient in fibroblasts from patients with Zellweger syndrome, infantile Refsum disease, neonatal and X-linked adrenoleukodystrophy, which explains for the accumulation of very long-chain fatty acids in all four disease entities. In Zellweger syndrome, infantile Refsum disease and neonatal adrenoleukodystrophy the impairment in peroxisomal very long-chain fatty acid beta-oxidation is probably caused by a strong deficiency of all peroxisomal beta-oxidation enzyme proteins due to a deficiency of peroxisomes.

Adrenoleukodystrophy↗
PubMed1987

Prenatal diagnosis of Zellweger syndrome by measurement of very long chain fatty acid (C26:0) beta-oxidation in cultured chorionic villous fibroblasts: implications for early diagnosis of other peroxisomal disorders.

In this paper we show that cultured chorionic villous fibroblasts efficiently catalyse the peroxisomal beta-oxidation of hexacosanoic acid (cerotic acid), a saturated very long chain fatty acid containing 26 carbon atoms. Hexacosanoic beta-oxidation was found to be strongly impaired in cultured chorionic villous fibroblasts from a Zellweger foetus. This finding indicates that measurement of peroxisomal beta-oxidation can be used (in addition to measurement of acyl-CoA:dihydroxyacetone phosphate acyltransferase, de novo plasmalogen biosynthesis, the amount of particle-bound catalase and phytanic acid oxidase) for prenatal diagnosis in the first trimester of Zellweger syndrome, infantile Refsum disease and neonatal adrenoleukodystrophy. The method should be equally applicable to the early prenatal diagnosis of disorders in which there is a deficiency of a single peroxisomal beta-oxidation enzyme. Such diseases include X-linked adrenoleukodystrophy (peroxisomal very long chain fatty acyl CoA ligase deficiency), 'pseudo-Zellweger syndrome' (peroxisomal 3-oxoacyl-CoA thiolase deficiency) and 'pseudo-neonatal adrenoleukodystrophy' (acyl-CoA oxidase deficiency).

Cells, Cultured↗
PubMed1987

X-linked adrenoleukodystrophy: defective peroxisomal oxidation of very long chain fatty acids but not of very long chain fatty acyl-CoA esters.

We investigated the peroxisomal fatty acid beta-oxidation system in liver and cultured skin fibroblasts from patients with X-linked adrenoleukodystrophy known to accumulate very long chain fatty acids. In order to examine whether the deficient peroxisomal oxidation of very long chain fatty acids in these patients results from a deficiency in one of the peroxisomal beta-oxidation enzyme proteins (acyl-CoA oxidase, bifunctional protein with enoyl-CoA hydratase and 3-hydroxyacyl-CoA dehydrogenase activities and 3-oxoacyl-CoA thiolase) we carried out immunoblotting experiments using antibodies directed against the peroxisomal beta-oxidation enzyme proteins from rat liver. Furthermore, we studied the oxidation of palmitoyl-CoA and lignoceroyl-CoA in homogenates of fibroblasts from the patients. The results indicate that the peroxisomal beta-oxidation enzyme proteins are not only present immunologically but also functionally active which suggests that the defect in X-linked adrenoleukodystrophy is, indeed, as recently suggested by Hashmi and coworkers (FEBS Lett 1986;196:247-250) at the level of a deficient peroxisomal activation of very long chain fatty acids.

Acyl Coenzyme A↗
PubMed1987

Studies on the peroxisomal oxidation of palmitate and lignocerate in rat liver.

We have investigated the pathways involved in the peroxisomal oxidation of palmitate and lignocerate, measured as the cyanide-insensitive formation of acetyl units, in rat-liver homogenates. The peroxisomal beta-oxidation of both fatty acids is dependent on the presence of ATP, coenzyme A, NAD+ and Mg2+. However, there is a striking difference in the dependence of the rate of oxidation of the two substrates on the concentration of the individual cofactors, especially ATP. The peroxisomal beta-oxidation of lignocerate was inhibited to a progressively greater extent by increasing concentrations of palmitate and vice versa. Activation of lignoceric acid to lignoceroyl-CoA, however, was not inhibited by increasing concentrations of palmitate, and vice versa. It can be concluded that the peroxisomal palmitate and lignocerate beta-oxidation pathways differ in at least one enzymic reaction (the synthetase), but that the two pathways share at least one common step.

Animals↗
PubMed1987

Peroxisomal fatty acid beta-oxidation in relation to the accumulation of very long chain fatty acids in cultured skin fibroblasts from patients with Zellweger syndrome and other peroxisomal disorders.

The peroxisomal oxidation of the long chain fatty acid palmitate (C16:0) and the very long chain fatty acids lignocerate (C24:0) and cerotate (C26:0) was studied in freshly prepared homogenates of cultured skin fibroblasts from control individuals and patients with peroxisomal disorders. The peroxisomal oxidation of the fatty acids is almost completely dependent on the addition of ATP, coenzyme A (CoA), Mg2+ and NAD+. However, the dependency of the oxidation of palmitate on the concentration of the cofactors differs markedly from that of the oxidation of lignocerate and cerotate. The peroxisomal oxidation of all three fatty acid substrates is markedly deficient in fibroblasts from patients with the Zellweger syndrome, the neonatal form of adrenoleukodystrophy and the infantile form of Refsum disease, in accordance with the deficiency of peroxisomes in these patients. In fibroblasts from patients with X-linked adrenoleukodystrophy the peroxisomal oxidation of lignocerate and cerotate is impaired, but not that of palmitate. Competition experiments indicate that in fibroblasts, as in rat liver, distinct enzyme systems are responsible for the oxidation of palmitate on the one hand and lignocerate and cerotate on the other hand. Fractionation studies indicate that in rat liver activation of cerotate and lignocerate to cerotoyl-CoA and lignoceroyl-CoA, respectively, occurs in two subcellular fractions, the endoplasmic reticulum and the peroxisomes but not in the mitochondria. In homogenates of fibroblasts from patients lacking peroxisomes there is a small (25%) but significant deficiency of the ability to activate very long chain fatty acids. This deficient activity of very long chain fatty acyl-CoA synthetase is also observed in fibroblast homogenates from patients with X-linked adrenoleukodystrophy. We conclude that X-linked adrenoleukodystrophy is caused by a deficiency of peroxisomal very long chain fatty acyl-CoA synthetase.

Facial Bones↗