Similar Datasets
Project description:Lipoprotein lipase (LPL) is responsible for the intravascular catabolism of triglyceride-rich lipoproteins and plays a central role in whole-body energy balance and lipid homeostasis. As such, LPL is subject to tissue-specific regulation in different physiological conditions, but the mechanisms of this regulation remain incompletely characterized. Previous work revealed that LPL comprises a set of proteoforms with different isoelectric points, but their regulation and functional significance have not been studied thus far. Here we studied the distribution of LPL proteoforms in different rat tissues and their regulation under physiological conditions. First, analysis by two-dimensional electrophoresis and Western blot showed different patterns of LPL proteoforms (i.e., different pI or relative abundance of LPL proteoforms) in different rat tissues under basal conditions, which could be related to the tissue-specific regulation of the enzyme. Next, the comparison of LPL proteoforms from heart and brown adipose tissue between adults and 15-day-old rat pups, two conditions with minimal regulation of LPL in these tissues, yielded virtually the same tissue-specific patterns of LPL proteoforms. In contrast, the pronounced down-regulation of LPL activity observed in white adipose tissue during fasting is accompanied by a prominent reconfiguration of the LPL proteoform pattern. Furthermore, refeeding reverts this down-regulation of LPL activity and restores the pattern of LPL proteoforms in this tissue. Importantly, this reversible proteoform-specific regulation during fasting and refeeding indicates that LPL proteoforms are functionally diverse. Further investigation of potential differences in the functional properties of LPL proteoforms showed that all proteoforms exhibit lipolytic activity and have similar heparin-binding affinity, although other functional aspects remain to be investigated. Overall, this study demonstrates the ubiquity, differential distribution and specific regulation of LPL proteoforms in rat tissues and underscores the need to consider the existence of LPL proteoforms for a complete understanding of LPL regulation under physiological conditions.
2024-01-26 | PXD043704 | Pride
Project description:LPL co-deregulated genes after LPL specific siRNA knock-down In chronic lymphocytic leukemia (CLL), lipoprotein lipase (LPL) mRNA overexpression is an established poor prognostic marker, its function, however, is poorly understood. Measuring extracellular LPL enzymatic activity and protein, we found no difference between levels in CLL patients and those of controls, both before and after heparin treatment in vivo and in vitro. Investigating LPL knock down effects, we determined five potential downstream targets, of which one gene, STXBP3, reportedly is involved in fatty acid metabolism. While possibly reflecting an epigenetic switch towards an incorrect transcriptional program, LPL overexpression by itself does not appear to significantly influence CLL cell survival.
2013-02-13 | E-GEOD-44247 | biostudies-arrayexpress
Project description:LPL co-deregulated genes after LPL specific siRNA knock-down In chronic lymphocytic leukemia (CLL), lipoprotein lipase (LPL) mRNA overexpression is an established poor prognostic marker, its function, however, is poorly understood. Measuring extracellular LPL enzymatic activity and protein, we found no difference between levels in CLL patients and those of controls, both before and after heparin treatment in vivo and in vitro. Investigating LPL knock down effects, we determined five potential downstream targets, of which one gene, STXBP3, reportedly is involved in fatty acid metabolism.
2013-02-13 | GSE44247 | GEO
Project description:Lipoprotein lipase (LPL) carries out the lipolytic processing of triglyceride-rich lipoproteins (TRL) along the luminal surface of capillaries. LPL activity is regulated by angiopoietin-like proteins (ANGPTL3, ANGPTL4, and ANGPTL8), which control the delivery of TRL-derived lipid nutrients to tissues in a temporal and spatial fashion. This regulation mediates the partitioning of lipid delivery to storage and metabolic tissues according to nutritional status. A complex between ANGPTL3 and ANGPTL8 (ANGPTL3/8) inhibits LPL activity in oxidative tissues, but its mode-of-action has remained unknown. Here, we used biophysical techniques to define how ANGPTL3/8 and ANGPTL3 interact with LPL and how they drive LPL inactivation. We demonstrate, by mass photometry, that ANGPTL3/8 is a heterotrimer with a 2:1 stoichiometry between ANGPTL3 and ANGPTL8 and that ANGPTL3 is a homotrimer. Hydrogen–deuterium exchange mass spectrometry (HDX-MS) studies revealed that both ANGPTL3/8 and ANGPTL3 use the proximal portion of their N-terminal α-helices to interact with sequences surrounding the catalytic pocket in LPL. That binding event triggers unfolding of LPL’s α/β- hydrolase domain and irreversible loss of LPL catalytic activity. The binding of LPL to its endothelial transporter protein (GPIHBP1) or to heparan-sulfate proteoglycans protects LPL from inactivation by unfolding, particularly against the unfolding triggered by ANGPTL3. Pulse-labelling HDX-MS studies revealed that ANGPTL3/8 and ANGPTL3 catalyze LPL unfolding in an ATP-independent fashion, which categorize these LPL inhibitors as atypical unfoldases. The catalytic nature of LPL unfolding by ANGPTL3/8 explains why low plasma concentrations of ANGPTL3/8 are effective in inhibiting a molar excess of LPL in capillaries.
2025-03-26 | PXD060125 | Pride
Project description:Lipoprotein lipase (Lpl) was predicted as a causal gene for abdominal using a novel statistical method named LCMS (Schadt et al., 2005, Nature Genetics). In order to validate this prediction, we profiled the liver tissues of lipoprotein lipase heterozygous knockout mice (Lpl+/-) and their littermate wild-type (wt) controls to examine the gene expression signature as well as pathways/networks resulting from the single gene perturbation. 8 Lpl+/- mice and 8 wt controls were profiled. Reference pool included RNA extracted from the liver of 9 wt control mice. Dye-swap was involved in the profiling.
2009-03-07 | E-GEOD-11991 | biostudies-arrayexpress
Project description:Lipoprotein lipase (LPL) is an extracellular lipase that preferentially hydrolyses triglycerides in triglyceride-rich lipoproteins within the circulation. LPL expression in macrophages contributes to atherosclerosis. In addition, the hydrolysis products liberated from lipoprotein lipids by LPL causes lipid accumulation and impairs cholesterol efflux ability in macrophages. However, the effects of LPL hydrolysis products in modulating the transcript profiles within macrophages and their roles in foam cell formation are not completely understood. We performed microarray analyses on THP-1 macrophages incubated with LPL hydrolysis products to identify differentially expressed genes.
2017-02-15 | GSE84791 | GEO
Project description:Sel1L is an adaptor protein for the E3 ligase Hrd1 in the endoplasmic reticulum-associated degradation (ERAD), but its physiological role in a cell-type-specific manner remains unclear. Here we show that mice with adipocyte-specific Sel1L deficiency are resistant to diet-induced obesity and exhibit postprandial hypertriglyceridemia. Mechanistically, our data demonstrate a critical requirement of Sel1L for the secretion of lipoprotein lipase (LPL), independently of its role in Hrd1-mediated ERAD and ER homeostasis. Further biochemical analyses revealed that Sel1L physically interacts and stabilizes the LPL maturation complex consisted of LPL and lipase-maturation factor 1 (LMF1). In the absence of Sel1L, LPL is retained in the ER and prone to the formation of protein aggregates, which are degraded by autophagy-mediated degradation. The Sel1L-mediated control of LPL secretion is seen in other LPL-expressing cell types as well such as cardiac muscle and macrophages. Thus, our study reports a novel role of Sel1L in LPL secretion and systemic lipid metabolism.
2015-05-18 | GSE56918 | GEO
Project description:Sel1L is an adaptor protein for the E3 ligase Hrd1 in the endoplasmic reticulum-associated degradation (ERAD), but its physiological role in a cell-type-specific manner remains unclear. Here we show that mice with adipocyte-specific Sel1L deficiency are resistant to diet-induced obesity and exhibit postprandial hypertriglyceridemia. Mechanistically, our data demonstrate a critical requirement of Sel1L for the secretion of lipoprotein lipase (LPL), independently of its role in Hrd1-mediated ERAD and ER homeostasis. Further biochemical analyses revealed that Sel1L physically interacts and stabilizes the LPL maturation complex consisted of LPL and lipase-maturation factor 1 (LMF1). In the absence of Sel1L, LPL is retained in the ER and prone to the formation of protein aggregates, which are degraded by autophagy-mediated degradation. The Sel1L-mediated control of LPL secretion is seen in other LPL-expressing cell types as well such as cardiac muscle and macrophages. Thus, our study reports a novel role of Sel1L in LPL secretion and systemic lipid metabolism. Sel1Lflox/flox mice were crossed with adiponectin promoter driven Cre mice to create adipose tissue-specific Sel1L-/- mice. Male wildtype C57Bl/6 mice and adipose tissue-specific Sel1l-/- mice were fed a high fat diet (Research Diets D12492) for 5 weeks. Adipose tissue was excised and used for microarray analysis.
2015-05-18 | E-GEOD-56918 | biostudies-arrayexpress
Project description:Lipoprotein lipase (Lpl) was predicted as a causal gene for abdominal using a novel statistical method named LCMS (Schadt et al., 2005, Nature Genetics). In order to validate this prediction, we profiled the liver tissues of lipoprotein lipase heterozygous knockout mice (Lpl+/-) and their littermate wild-type (wt) controls to examine the gene expression signature as well as pathways/networks resulting from the single gene perturbation.
2009-03-08 | GSE11991 | GEO