cDNA cloning of human milk bile-salt-stimulated lipase and evidence for its identity to pancreatic carboxylic ester hydrolase
We have isolated and sequenced cDNA clones covering the entire coding sequence of human-milk bile-salt-stimulated lipase, as well as 996 nucleotides of the 3' end of the pancreatic enzyme carboxylic ester hydrolase. The deduced amino acid sequence of the lipase starts with a 23-residue leader peptide. The open reading frame continues with 722 amino acid residues. The sequence contains in the C-terminal part a proline-rich repeat, 16 repeats of 11 amino acid residues each. The mRNA was estimated to be approximately 2500 nucleotides from Northern blot and of similar size in mammary and pancreatic tissues. Data obtained indicate that the lipase and the carboxylesterase are identical and coded for by the same gene. The cDNA is 2428 bases long, which indicates that a near full-length copy of the transcript has been isolated. Comparisons with other enzymes show that the lipase is a new member of the supergene family of serine hydrolases. It is not only closely related (and in its N-terminal half virtually identical) to lysophospholipase from rat pancreas and cholesterol esterase from bovine pancreas, but also shows a high degree of similarity to several esterases, e.g. acetylcholine esterase. In contrast, no such similarity could be found to typical lipases.
[Show abstract] [Hide abstract] ABSTRACT: Bodily secretions, including breast milk and semen, contain factors that modulate HIV-1 infection. Since anal intercourse caries one of the highest risks for HIV-1 transmission, our aim was to determine whether colorectal mucus (CM) also contains factors interfering with HIV-1 infection and replication. CM from a number of individuals was collected and tested for the capacity to bind DC-SIGN and inhibit HIV-1 cis- or trans -infection of CD4+ T-lymphocytes. To this end, a DC-SIGN binding ELISA, a gp140 trimer competition ELISA and HIV-1 capture/ transfer assays were utilized. Subsequently we aimed to identify the DC-SIGN binding component through biochemical characterization and mass spectrometry analysis. CM was shown to bind DC-SIGN and competes with HIV-1 gp140 trimer for binding. Pre-incubation of Raji-DC-SIGN cells or immature dendritic cells (iDCs) with CM potently inhibits DC-SIGN mediated trans -infection of CD4+ T-lymphocytes with CCR5 and CXCR4 using HIV-1 strains, while no effect on direct infection is observed. Preliminary biochemical characterization demonstrates that the component seems to be large (> 100kDa), heat and proteinase K resistant, binds in a α1-3 mannose independent manner and is highly variant between individuals. Immunoprecipitation using DC-SIGN-Fc coated agarose beads followed by mass spectrometry indicated lactoferrin (fragments) and its receptor (intelectin-1) as candidates. Using ELISA we showed that lactoferrin levels within CM correlate with DCSIGN binding capacity. In conclusion, CM can bind the C-type lectin DC-SIGN and block HIV-1 trans -infection of both CCR5 and CXCR4 using HIV-1 strains. Furthermore, our data indicate that lactoferrin is a DC-SIGN binding component of CM. These results indicate that CM has the potential to interfere with pathogen transmission and modulate immune responses at the colorectal mucosa.0Comments 1Citation
- "Previously, BSSL from human milk has been demonstrated to bind DC-SIGN and inhibit trans-infection, while certain allele combinations are correlated with a lower risk of HIV-1 infection, indicating BSSL potentially protects against transmission [9,10,28]. Furthermore, this molecule is produced in the pancreas and can be released into the duodenum, making it likely that BSSL or smaller digested fragments could be present in CM . However, neither MUC proteins nor BSSL were identified in the DC-SIGN pull-down assay indicating that if these glycoproteins are present, they are only so in limited amounts. "
[Show abstract] [Hide abstract] ABSTRACT: Addition of lutein to dairy products is an alternative that widens the range of foods which could be lutein sources. However, bioaccessibility is an essential aspect to be considered during the development of products with added bioactive substances. We evaluated the in vitro bioaccessibility of lutein esters added to milk and yogurt with different fat contents, and determined the efficiency of enzymatic hydrolysis of the esters during digestion. Bioaccessibility of lutein and efficiency of hydrolysis were significantly lower in skimmed products than semi-skimmed and whole products, indicating that a minimal amount of fat is required to allow micellization and hydrolysis. The efficiency of ester hydrolysis ranged between 12 and 35%, which was attributed to pancreatic lipase. Whole and semi-skimmed samples were shown to be good vehicles for the addition of lutein, since presented bioaccessibility indices (38.3–47.5%) are similar to those found in natural food sources of xanthophylls.0Comments 1Citation
- "Cholesterol esterase is produced by the pancreas and by the mammary glands in higher mammals, and if present in milk or yogurt could take part in the hydrolysis of esters (Hui & Howles, 2002 ). Nevertheless, it is unlikely that considerable concentrations of this enzyme would be present in milk or yogurt used in this study, since the commercial sterilization processing (UHT) of milk would inactivate this enzyme (Nilsson et al., 1990). "
[Show abstract] [Hide abstract] ABSTRACT: Bile-salt activated carboxylic ester lipase (CEL) is a major triglyceride, cholesterol ester and vitamin ester hydrolytic enzyme contained within pancreatic and lactating mammary gland secretions. Bioinformatic methods were used to predict the amino acid sequences, secondary and tertiary structures and gene locations for CEL genes, and encoded proteins using data from several vertebrate genome projects. A proline-rich and O-glycosylated 11-amino acid C-terminal repeat sequence (VNTR) previously reported for human and other higher primate CEL proteins was also observed for other eutherian mammalian CEL sequences examined. In contrast, opossum CEL contained a single C-terminal copy of this sequence whereas CEL proteins from platypus, chicken, lizard, frog and several fish species lacked the VNTR sequence. Vertebrate CEL genes contained 11 coding exons. Evidence is presented for tandem duplicated CEL genes for the zebrafish genome. Vertebrate CEL protein subunits shared 53-97% sequence identities; demonstrated sequence alignments and identities for key CEL amino acid residues; and conservation of predicted secondary and tertiary structures with those previously reported for human CEL. Phylogenetic analyses demonstrated the relationships and potential evolutionary origins of the vertebrate CEL family of genes which were related to a nematode carboxylesterase (CES) gene and five mammalian CES gene families.0Comments 5Citations
- "Moreover, rare CEL gene defects in this region are responsible for a monogenically derived diabetes condition called maturityonset diabetes of the young type 8 (MODY8), also known as diabetes and pancreatic exocrine dysfunction (DPED), which causes a defect in insulin secretion [31, 32]. Human CEL is expressed predominantly in the lactating mammary gland and beta cells of the exocrine pancreas, where the enzyme contributes significantly to triglyceride, cholesterol ester and vitamin ester metabolism5678910. CEL also promotes large chylomicron production in the intestine, and its presence in plasma supports interactions with cholesterol and oxidized lipoproteins  which may influence atherosclerosis progression . "