Protein lysosomal lipase

OBJECTIVE: To explore the role of LAL (lysosomal acid lipase) in macrophage cholesterol efflux and whole-body reverse cholesterol transport. APPROACH AND RESULTS: Immortalized peritoneal macrophages from lal-/ - mice showed reduced expression of ABCA1 (ATP-binding cassette transporter A1) and ABCG1 (ATP-binding cassette transporter G1), reduced production of the regulatory oxysterol 27-hydroxycholesterol, and impaired suppression of cholesterol synthesis on exposure to acetylated low-density lipoprotein when compared with lal+/+ macrophages...

Recombinant therapeutic proteins are becoming very important pharmaceutical agents for treating intractable diseases. Most biopharmaceutical proteins are produced in mammalian cells because this ensures correct folding and glycosylation for protein stability and function. However, protein production in mammalian cells has several drawbacks, including heterogeneity of glycans attached to the produced protein. In this study, we established cell lines with high-mannose-type asparagine (N)-linked, low-complexity glycans...

BACKGROUND: Lysosomal acid lipase deficiency is an autosomal recessive metabolic disease with a wide range of severity from Wolman Disease to Cholesterol Ester Storage Disease. Recently enzyme replacement therapy with sebelipase alpha has been approved by drug agencies for treatment of this lysosomal disease. Ezetimibe is an azetidine derivative which blocks Niemann Pick C1-Like 1 Protein; as its consequence, plasmatic concentration of low density lipoproteins and other apoB-containing lipoproteins, that are the substrate of lysosomal acid lipase, are decreased...

Tumors depend on their microenvironment for sustained growth, invasion, and metastasis. In this environment, endothelial cells (ECs) are an important stromal cell type interacting with malignant cells to facilitate tumor angiogenesis and cancer cell extravasation. Of note, lysosomal acid lipase (LAL) deficiency facilitates melanoma growth and metastasis. ECs from LAL-deficient ( lal -/- ) mice possess enhanced proliferation, migration, and permeability of inflammatory cells by activating the mammalian target of rapamycin (mTOR) pathway...

OBJECTIVE: To gain mechanistic insights into the role of LIPA (lipase A), the gene encoding LAL (lysosomal acid lipase) protein, in human macrophages. APPROACH AND RESULTS: We used CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 (CRISPR-associated protein 9) technology to knock out LIPA in human induced pluripotent stem cells and then differentiate to macrophage (human-induced pluripotent stem cells-derived macrophage [IPSDM]) to explore the human macrophage LIPA loss-of-function phenotypes...

Niemann-Pick type C (NPC) disease is an inherited, progressive neurodegenerative disorder principally caused by mutations in the NPC1 gene. NPC disease is characterized by the accumulation of unesterified cholesterol in the late endosomes (LE) and lysosomes (Ly) (LE/Ly). Vorinostat, a histone deacetylase inhibitor (HDACi), restores cholesterol homeostasis in fibroblasts derived from NPC patients; however, the exact mechanism by which Vorinostat restores cholesterol level is not known yet. In this study, we performed comparative proteomic profiling of the response of NPC1(I1061T) fibroblasts to Vorinostat...

Although many pharmaceutical proteins are produced in mammalian cells, there remains a challenge to select cell lines that express recombinant proteins with high productivity. Since most biopharmaceutical proteins are secreted by cells into the medium, it is difficult to select cell lines that produce large amounts of the target protein. To address this issue, a new protein expression system using the glycosylphosphatidylinositol (GPI)-anchor was developed. PGAP2 is involved in processing GPI-anchored proteins (GPI-APs) during transport...

Lysosomal acid lipase (LAL) is a critical neutral lipid metabolic enzyme that regulates metabolic reprogramming in myeloid-derived suppressor cells (MDSCs) through over-activation of mammalian target of rapamycin (mTOR). Affymetrix GeneChip microarray analysis of MDSCs from LAL deficient mouse (lal-/-) revealed upregulation of Rab7 GTPase protein, which belongs to a superfamily of small-molecular-weight GTPase known to regulate intracellular membrane trafficking from early to late endosomes and lysosomes. Here, the physical protein-protein interaction between Rab7 GTPase and mTOR has been detected by co-immunoprecipitation in the cell extract of wild type HD1A and lal-/- MDSC-like HD1B myeloid cell lines...

BACKGROUND: Abdominal aortic aneurysm (AAA) is a multifactorial disease with strong genetic components. Various genetic loci have been associated with clinical AAA, but few studies have investigated pathological AAA, an intermediate phenotype of the disease. METHODS: We examined 2263 consecutive autopsies of older Japanese subjects from a study on geriatric diseases in Japanese individuals (The JG-SNP study). The presence of AAA was determined with a pathological diagnosis during autopsy...

OBJECTIVE: Genome-wide association studies have linked variants at chromosome 10q23 with increased coronary artery disease risk. The disease-associated variants fall in LIPA, which encodes lysosomal acid lipase (LAL), the enzyme responsible for lysosomal cholesteryl ester hydrolysis. Loss-of-function mutations in LIPA result in accelerated atherosclerosis. Surprisingly, the coronary artery disease variants are associated with increased LIPA expression in some cell types. In this study, we address this apparent contradiction...

Low-density lipoprotein (LDL) is the major source of lipid within atherosclerotic lesions. Myeloperoxidase (MPO) is present in lesions and forms the reactive oxidants hypochlorous acid (HOCl) and hypothiocyanous acid (HOSCN). These oxidants modify LDL and have been strongly linked with the development of atherosclerosis. In this study, we examined the effect of HOCl, HOSCN and LDL pre-treated with these oxidants on the function of lysosomal enzymes responsible for protein catabolism and lipid hydrolysis in murine macrophage-like J774A...

Lysosomal acid lipase deficiency (LAL-D) is a rare disorder of cholesterol metabolism with an autosomal recessive mode of inheritance. The absence or deficiency of the LAL enzyme gives rise to pathological accumulation of cholesterol esters in various tissues. A severe LAL-D phenotype manifesting in infancy is associated with adrenal calcification and liver and gastrointestinal involvement with characteristic early mortality. LAL-D presenting in childhood and adulthood is associated with hepatomegaly, liver fibrosis, cirrhosis, and premature atherosclerosis...

Complex antigens require processing within antigen-presenting cells (APCs) to form T cell stimulatory complexes with CD1 antigen-presenting molecules. It remains unknown whether lipids with multi-acylated moieties also necessitate digestion by lipases to become capable of binding CD1 molecules and stimulate T cells. Here, we show that the mycobacterial tetra-acylated glycolipid antigens phosphatidyl-myo-inositol mannosides (PIM) are digested to di-acylated forms by pancreatic lipase-related protein 2 (PLRP2) and lysosomal phospholipase A2 (LPLA2) within APCs...

Infiltrating monocyte-derived macrophages (M-MΦ) influence stroke-induced brain injury. Although the inflammatory nature of M-MΦ in acute stroke has been well documented, their role during the resolution phase of stroke is less clear. With emerging evidence for the involvement of scavenger receptors in innate immunity, this study addresses an M-MΦ CD36 role in mediating phagocytosis during the recovery phase of stroke. Stroke increases CD36 and TSP-1/2 mRNA levels in the ipsilateral hemisphere at acute (3-day (d)) and recovery (7d) periods...

Autophagy maintains cellular quality control by degrading organelles, and cytosolic proteins and their aggregates in lysosomes. Autophagy also degrades lipid droplets (LD) through a process termed lipophagy. During lipophagy, LD are sequestered within autophagosomes and degraded by lysosomal acid lipases to generate free fatty acids that are β-oxidized for energy. Lipophagy was discovered in hepatocytes, and since then has been shown to function in diverse cell types. Whether lipophagy degrades LD in the major fat storing cell-the adipocyte-remained unclear...

The recognition of CD1-lipid complexes by T cells was discovered 20 years ago and has since been an emerging and expanding field of investigation. Unlike protein antigens, which are presented on MHC class I and II molecules, lipids can only be presented by CD1 molecules, a unique family of MHC-like proteins whose singularity is a hydrophobic antigen-binding groove. The processing and loading of lipid antigens inside this groove of CD1 molecules require localization to endosomal and lysosomal subcellular compartments and their acidic pHs...

AIMS/HYPOTHESIS: Lysosomal acid lipase (LAL) hydrolyses cholesteryl esters and triacylglycerols (TG) within lysosomes to mobilise NEFA and cholesterol. Since LAL-deficient (Lal (-/-) ) mice suffer from progressive loss of adipose tissue and severe accumulation of lipids in hepatic lysosomes, we hypothesised that LAL deficiency triggers alternative energy pathway(s). METHODS: We studied metabolic adaptations in Lal (-/-) mice. RESULTS: Despite loss of adipose tissue, Lal (-/-) mice show enhanced glucose clearance during insulin and glucose tolerance tests and have increased uptake of [(3)H]2-deoxy-D-glucose into skeletal muscle compared with wild-type mice...

Considering the biological function of α-tocopherol (α-Toc) as a potent protective factor against oxidative stress, this antioxidant is in the focus of aging research. To understand the role of α-Toc during aging we investigated α-Toc concentrations in young and aged primary human fibroblasts after supplementation with RRR-α-Toc. Additionally, α-Toc contents were determined in brain, kidney, and liver tissue of 10 week-, 18 month-, and 24 month-old mice, which were fed a standard diet containing 100 mg/kg dl-α-tocopheryl acetate...

UNLABELLED: The hepatitis E virus (HEV) sheds into feces as nonenveloped virions but circulates in the blood in a membrane-associated, quasi-enveloped form (eHEV). Since the eHEV virions lack viral proteins on the surface, we investigated the entry mechanism for eHEV. We found that compared to nonenveloped HEV virions, eHEV attachment to the cell was much less efficient, requiring a longer inoculation time to reach its maximal infectivity. A survey of cellular internalization pathways identified clathrin-mediated endocytosis as the main route for eHEV entry...

Proteins are major targets for oxidative damage in vivo due to their high abundance and rapid rates of reaction with both one-electron (radical) and two-electron oxidants (e.g. singlet oxygen, hypochlorous acid, peroxynitrous acid, reactive aldehydes). The turnover of both native and modified proteins is critical for maintenance of cell homeostasis, with this occurring via multiple pathways including proteasomes (for cytosolic species), the Lon protease (in mitochondria), and the endo-lysosomal systems (both extra- and intra-cellular species)...