Buchler C

References (3)

Title : Transcriptional regulation of lysosomal acid lipase in differentiating monocytes is mediated by transcription factors Sp1 and AP-2 - Ries_1998_J.Lipid.Res_39_2125
Author(s) : Ries S , Buchler C , Langmann T , Fehringer P , Aslanidis C , Schmitz G
Ref : J Lipid Res , 39 :2125 , 1998
Abstract : Human lysosomal acid lipase (LAL) is a hydrolase required for the cleavage of cholesteryl esters and triglycerides derived from plasma lipoproteins. It is shown here that during monocyte to macrophage differentiation, the expression of LAL-mRNA is induced. This induction is dependent on protein kinase C activity and protein synthesis. The cell type-specific increase in LAL expression is further investigated in the THP-1 cell line with respect to transcriptional regulation. The human monocytic leukemia cell line THP-1 differentiates into macrophage-like cells when treated with phorbol esters. In order to determine the cis-acting elements necessary for both basal and phorbol 12-myristate-13 acetate (PMA)-enhanced promoter activity, we performed deletion analysis and reporter gene assays. A PMA responsive element has been identified between -182 bp and -107 bp upstream of the major transcription start site. Gel mobility shift assays demonstrated that binding of Sp1 and AP-2 to the LAL promoter is increased by PMA in THP-1 cells. Co-transfections with expression plasmids for Sp1 and AP-2 further emphasized the important role of these transcription factors in both basal and PMA-enhanced LAL expression. Our data suggest that differentiation dependent increase of lysosomal acid lipase (LAL) expression in THP-1 cells is mediated by a concerted action of Sp1 and AP-2.
ESTHER : Ries_1998_J.Lipid.Res_39_2125
PubMedSearch : Ries_1998_J.Lipid.Res_39_2125
PubMedID: 9799798
Gene_locus related to this paper: human-LIPA

Title : Different missense mutations in histidine-108 of lysosomal acid lipase cause cholesteryl ester storage disease in unrelated compound heterozygous and hemizygous individuals - Ries_1998_Hum.Mutat_12_44
Author(s) : Ries S , Buchler C , Schindler G , Aslanidis C , Ameis D , Gasche C , Jung N , Schambach A , Fehringer P , Vanier MT , Belli DC , Greten H , Schmitz G
Ref : Hum Mutat , 12 :44 , 1998
Abstract : Cholesteryl ester storage disease (CESD) and Wolman disease (WD) are both autosomal recessive disorders associated with reduced activity of lysosomal acid lipase (LAL), that leads to the tissue accumulation of cholesteryl esters in endosomes and lysosomes. WD is caused by genetic defects of LAL that leave no residual enzymatic activity, while in CESD patients a residual LAL activity can be identified. We have analyzed the LAL cDNA in three CESD patients from two nonrelated families and identified the mutations responsible for the disease. The associated genetic defects characterized revealed compound heterozygosity for a splice defect leading to skipping of exon 8, due to a G-->A transition at position -1 of the exon 8 splice donor site, and a point mutation leading to a Hisl08Pro change (CAT-->CCT) in two patients (siblings) with mild CESD phenotype. A further CESD patient was hemizygous for a His108-->Arg missense mutation (CAT-->CGT) in combination with a partial deletion of the LAL gene and was affected more severely. Expression of the LAL enzymes with the His108-->Pro and His108-->Arg mutation in insect cells revealed residual enzymatic activities of 4.6% versus 2.7%, respectively, compared with controls. Therefore, His108 seems to play a crucial role in folding or catalytic activity of the lysosomal acid lipase. This is the first description of two different, naturally occurring mutations involving the same amino acid residue in the lysosomal acid lipase in unrelated CESD patients. Moreover, our results demonstrate that the variable manifestation of CESD can be explained by mutation-dependent, variable inactivation of the LAL enzyme.
ESTHER : Ries_1998_Hum.Mutat_12_44
PubMedSearch : Ries_1998_Hum.Mutat_12_44
PubMedID: 9633819
Gene_locus related to this paper: human-LIPA

Title : Genetic and biochemical evidence that CESD and Wolman disease are distinguished by residual lysosomal acid lipase activity - Aslanidis_1996_Genomics_33_85
Author(s) : Aslanidis C , Ries S , Fehringer P , Buchler C , Klima H , Schmitz G
Ref : Genomics , 33 :85 , 1996
Abstract : Cholesteryl ester storage disease (CESD) and Wolman disease are both autosomal recessive disorders associated with reduced activity and genetic defects of lysosomal acid lipase (LAL). We provide evidence that the strikingly more severe course of Wolman disease is caused by genetic defects of LAL that leave no residual enzyme activity. In a CESD patient, a G --> A mutation at position -1 of the exon 8 splice donor site results in skipping of exon 8 in 97% of the LAL hnRNA originating from this allele, while 3% are spliced correctly, resulting in full-length LAL enzyme. The mutant LAL mRNA codes for a protein lacking amino acids 254 to 277. On the other allele, a G --> T mutation leads to a premature stop codon at Gly245, resulting in inactive LAL enzyme. In addition, the previously identified Leu179 --> Pro mutation is present on this allele, and the LAL mRNA is rendered unstable by the premature stop codon. Analysis of two children with Wolman disease showed that both were homozygous for a G --> A mutation at position +1 of the same splice donor site as for the CESD patient, leading to skipping of exon 8. In contrast to the CESD patient, no correctly spliced mRNA was detectable. We have also expressed a wildtype LAL cDNA and the mutant LAL cDNA from one Wolman patient in Sf9 and H5 insect cells. We demonstrate that the LAL enzyme generated from the wildtype LAL cDNA was active in homogenates from Sf9 and H5 cells, while the enzyme with the internal deletion of 24 amino acids originating from the LAL cDNA of the Wolman patient was not. The combined data provide evidence that the only functionally relevant genetic difference between the Wolman patients and the CESD patient is that the splice defect in Wolman, which affects one of the invariable nucleotides of the splice consensus sequences (position +1), does not permit any correct splicing, whereas the defect observed in CESD (position -1) allows some correct splicing (3% of total LAL mRNA) and therefore the synthesis of functional enzyme.
ESTHER : Aslanidis_1996_Genomics_33_85
PubMedSearch : Aslanidis_1996_Genomics_33_85
PubMedID: 8617513
Gene_locus related to this paper: human-LIPA