Peturbation of PICALM Levels Alters Cellular Cholesterol Metabolism
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE64855 | GEO | 2015/06/17
SECONDARY ACCESSION(S): PRJNA272401
REPOSITORIES: GEO
Similar Datasets
Project description:PICALM (Phosphatidyl Inositol Clathrin Assembly Lymphoid Myeloid protein) is a ubiquitously expressed protein that plays a role in clathrin-mediated endocytosis. PICALM also affects the internalization of SNAREs and modulates macroautophagy. Chromosomal translocations that result in the fusion of PICALM to heterologous proteins cause leukemias, and genome-wide association studies have linked Single Nucleotide Polymorphisms (SNPs) of PICALM to Alzheimer’s disease. To obtain insight into the biological role of PICALM, we performed gene expression studies of PICALM-deficient and PICALM-expressing cells. Pathway analysis demonstrated that PICALM expression influences the expression of genes that encode proteins involved in cholesterol biosynthesis and lipoprotein uptake. GC-MS studies indicated that loss of PICALM increases total cholesterol pool size. Isotopic labeling studies revealed that loss of PICALM alters cholesterol homeostasis via increased scavenging of cholesterol. Measurement of LDL receptor endocytosis further showed that PICALM deficient cells express higher LDLR levels resulting in higher lipoprotein internalization. These findings suggest that PICALM is required for cellular cholesterol homeostasis and point to a novel mechanism by which PICALM alterations may contribute to disease. Total RNA was isolated (Qiagen RNeasy® Micro kit, Valencia, CA) from four replicates of PICALM knockout cells transfected with control vector, and from four replicates of PICALM knockout cells transfected with PICALM.
2015-06-17 | E-GEOD-64855 | biostudies-arrayexpress
Project description:We show that antigen internalization depends both on constitutive, clathrin-mediated endocytosis and on antigen-induced, clathrin-independent endocytosis mediated by endophilin A2. Although endophilin A2-mediated endocytosis is dispensable for antigen presentation, it is selectively required for metabolic support of B cell proliferation, in part through regulation of iron uptake. Consequently, endophilin A2 deficient mice show defects in GC B cell responses and production of high-affinity IgG. The requirement for endophilin A2 highlights a unique importance of clathrin-independent intracellular trafficking in GC B cell clonal expansion and antibody responses
2021-07-19 | GSE172295 | GEO
Project description:Clathrin-mediated endocytosis is essential for a wide range of cellular functions. We used a multi- step siRNA-based screening strategy to identify novel regulators of the first step of clathrin- mediated endocytosis, formation of clathrin-coated vesicles (CCVs) at the plasma membrane. A primary genome-wide screen identified 334 hits that caused accumulation of CCV cargo on the cell surface. A secondary screen identified 92 hits that inhibited cargo uptake and/or altered the morphology of clathrin-coated structures. The hits include components of four functional complexes: coat proteins, V-ATPase subunits, spliceosome-associated proteins, and acetyltransferase subunits. Electron microscopy revealed that V-ATPase depletion caused the cell to form aberrant non-constricted clathrin-coated structures at the plasma membrane. The V- ATPase knockdown phenotype was rescued by addition of exogenous cholesterol, indicating that the knockdown blocks clathrin-mediated endocytosis by preventing cholesterol from recycling from endosomes back to the plasma membrane. The microarray analysis was performed to test whether the siRNA targets are expressed in the cell lines used in the screen. For the microarray analysis of gene expression, the two cell lines used in the study were analyzed in duplicate: HeLa-YXXΦ and HeLa-FXNPXY (Hela-M cells expressing a CD8-YXXΦ and CD8-FXNPXY constructs respectively). YXXΦ and FXNPXY are motifs for clathrin-mediated endocytosis.
2012-12-01 | E-GEOD-39954 | biostudies-arrayexpress
Project description:Clathrin-mediated endocytosis is essential for a wide range of cellular functions. We used a multi- step siRNA-based screening strategy to identify novel regulators of the first step of clathrin- mediated endocytosis, formation of clathrin-coated vesicles (CCVs) at the plasma membrane. A primary genome-wide screen identified 334 hits that caused accumulation of CCV cargo on the cell surface. A secondary screen identified 92 hits that inhibited cargo uptake and/or altered the morphology of clathrin-coated structures. The hits include components of four functional complexes: coat proteins, V-ATPase subunits, spliceosome-associated proteins, and acetyltransferase subunits. Electron microscopy revealed that V-ATPase depletion caused the cell to form aberrant non-constricted clathrin-coated structures at the plasma membrane. The V- ATPase knockdown phenotype was rescued by addition of exogenous cholesterol, indicating that the knockdown blocks clathrin-mediated endocytosis by preventing cholesterol from recycling from endosomes back to the plasma membrane. The microarray analysis was performed to test whether the siRNA targets are expressed in the cell lines used in the screen.
2012-12-01 | GSE39954 | GEO
Project description:Triglyceride-rich lipoproteins and their remnants contribute to atherosclerosis, possibly by carrying remnant cholesterol and/or by exerting a pro-inflammatory effect on macrophages. Nevertheless, little is known about how macrophages process triglyceride-rich lipoproteins. We show that uptake by macrophages of VLDL-sized emulsion particles is dependent on the enzyme lipoprotein lipase via its C-terminal domain. Subsequent internalization of VLDL-triglycerides by macrophages is carried out by caveolae-mediated endocytosis, followed by hydrolysis by lysosomal acid lipase. STARD3 is required for the transfer of lysosomal fatty acids to the ER for lipid storage, while NPC1 likely is involved in promoting the extracellular efflux of fatty acids. Our data provide novel insights into how macrophages process VLDL-derived triglycerides and suggest that macrophages have the remarkable capacity to excrete internalized triglycerides as fatty acids.
2022-05-21 | GSE203250 | GEO
Project description:As the unique cell type in articular cartilage, chondrocyte senescence is a crucial cellular event contributing to osteoarthritis development. Here we show that clathrin-mediated endocytosis and activation of Notch signaling promotes chondrocyte senescence and osteoarthritis development, which is negatively regulated by myosin light chain 3. Myosin light chain 3 (MYL3) protein levels decline sharply in senescent chondrocytes of cartilages from model mice and osteoarthritis (OA) patients. Conditional deletion of Myl3 in chondrocytes significantly promoted, whereas intra-articular injection of adeno-associated virus overexpressing MYL3 delayed, OA progression in male mice. MYL3 deficiency led to enhanced clathrin-mediated endocytosis by promoting the interaction between myosin VI and clathrin, further inducing the internalization of Notch and resulting in activation of Notch signaling in chondrocytes. Pharmacologic blockade of clathrin-mediated endocytosis-Notch signaling prevented MYL3 loss-induced chondrocyte senescence and alleviated OA progression in mice. Our results establish a previously unknown mechanism essential for cellular senescence and provide a potential therapeutic direction for OA.
2023-09-07 | PXD044684 | Pride
Project description:Toll-like receptor 4 (TLR4) plays a pivotal role in the host response to lipopolysaccharide (LPS), a major cell wall component of Gram-negative bacteria. Here we elucidated whether the endocytic adaptor protein Disabled-2 (Dab2) that is abundantly expressed in the macrophages plays a role in LPS-stimulated TLR4 signaling and trafficking. Molecular analysis and transcriptome profiling of the RAW264.7 macrophage-like cells expressing short-hairpin RNA of Dab2 revealed that Dab2 mainly regulated LPS-stimulated TRIF-dependent, but not MyD88-dependent TLR4 signaling. Consequently, knockdown of Dab2 augmented TRIF-dependent interferon regulatory factor 3 activation and the expression for the subsets of inflammatory cytokines and interferon-inducible genes. We further delineated that Dab2 acted as a “clathrin sponge” and sequestered clathrin from TLR4/MD2 complex in the resting stage of macrophages. Clathrin was released from Dab2 and associated with TLR4 to facilitate the internalization of TLR4/MD2 complex together with the bound ligand from the cell surface upon LPS stimulation. Dab2 thereby functions as a negative immune regulator of TLR4 endocytosis and signaling, supporting a novel role of Dab2-associated regulatory circuit in the control of inflammatory response of macrophage to endotoxin.
2017-02-09 | GSE81088 | GEO
Project description:The purpose of this study was to determine whether there were differences in gene expression in the hippocampus, a part of the brain involved in memory consolidation, between male mice with age-related memory deficits (SAMP8 mice) and control mice with no age-related memory deficits. The senescence-accelerated mouse (SAMP8) strain exhibits decreased learning and memory and increased amyloid beta peptide (Aβ) accumulation at 12 months compared to 4 months. To detect differences in gene expression in SAMP8 mice, we used a Control mouse that was a 50% cross between SAMP8 and CD-1 mice and which showed no memory deficits (50% SAMP8 mouse). We then compared gene expression in the hippocampus of 4 month and 12 month old SAMP8 and Control mice using Affymetrix gene arrays. At 12 months, but not at 4 months, pathway analysis revealed significant differences in the Long Term Potentiation (LTP) (6 genes), Phosphatidylinositol Signaling (6 genes), and Endocytosis (10 genes) pathways. The changes in LTP included MAPK signaling (N-ras, CREB binding protein, protein phosphatase inhibitor 1) and Ca-dependent signaling (PI receptors 1 and 2 and phospholipase C). Changes in phosphatidylinositol signaling genes suggested altered signaling through PI3-kinase, and Western blotting revealed phosphorylation changes in AKT and 70S6K. Changes in the Endocytosis pathway involved genes related to clathrin-mediated endocytosis (dynamin and clathrin). Endocytosis is required for receptor recycling, is involved in Aβ metabolism, and is regulated by phosphatidylinositol signaling. In summary, these studies demonstrate altered genes expression in three SAMP8 hippocampal pathways associated with memory formation and consolidation. These pathways may provide new therapeutic targets in addition to targeting Aβ metabolism itself. Global differential profiling of hippocampal gene expression (4 month and 12 month old SAMP8 and Control mice) was performed using Affymetrix GeneChip® Mouse Genome 430 2.0 Arrays. At 12 months, but not at 4 months, pathway analysis revealed significant differences in the Long Term Potentiation (LTP) (6 genes), Phosphatidylinositol Signaling (6 genes), and Endocytosis (10 genes) pathways. The changes in LTP included MAPK signaling (N-ras, CREB binding protein, protein phosphatase inhibitor 1) and Ca-dependent signaling (PI receptors 1 and 2 and phospholipase C). Changes in phosphatidylinositol signaling genes suggested altered signaling through PI3-kinase, and Western blotting revealed phosphorylation changes in AKT and 70S6K. Changes in the Endocytosis pathway involved genes related to clathrin-mediated endocytosis (dynamin and clathrin). Endocytosis is required for receptor recycling, is involved in Aβ metabolism, and is regulated by phosphatidylinositol signaling. In summary, these studies demonstrate altered genes expression in three SAMP8 hippocampal pathways associated with memory formation and consolidation. These pathways may provide new therapeutic targets in addition to targeting Aβ metabolism itself. 2-way ANOVA (2 x 2 conditions, n=4). First variable was age (4 and 12 months) and second variable was mouse strain (Control and SAMP8). This results in 4 groups: Control-4 month, Control-12 month, SAMP8-4 month, and SAMP8-12 month. Each group had 4 biological replicates (4 mice). The ”Control” mice were a 50% backcross of the SAMP8 mice with CD-1 mice (50% SAMP8 mice). These mice were closely related to SAMP8 mice but exhibited no memory deficits at 4 or 12 months. The SAMP8 mice had memory deficits at 12 months but not at 4 months.
2013-08-30 | E-GEOD-49699 | biostudies-arrayexpress
Project description:The purpose of this study was to determine whether there were differences in gene expression in the hippocampus, a part of the brain involved in memory consolidation, between male mice with age-related memory deficits (SAMP8 mice) and control mice with no age-related memory deficits. The senescence-accelerated mouse (SAMP8) strain exhibits decreased learning and memory and increased amyloid beta peptide (Aβ) accumulation at 12 months compared to 4 months. To detect differences in gene expression in SAMP8 mice, we used a Control mouse that was a 50% cross between SAMP8 and CD-1 mice and which showed no memory deficits (50% SAMP8 mouse). We then compared gene expression in the hippocampus of 4 month and 12 month old SAMP8 and Control mice using Affymetrix gene arrays. At 12 months, but not at 4 months, pathway analysis revealed significant differences in the Long Term Potentiation (LTP) (6 genes), Phosphatidylinositol Signaling (6 genes), and Endocytosis (10 genes) pathways. The changes in LTP included MAPK signaling (N-ras, CREB binding protein, protein phosphatase inhibitor 1) and Ca-dependent signaling (PI receptors 1 and 2 and phospholipase C). Changes in phosphatidylinositol signaling genes suggested altered signaling through PI3-kinase, and Western blotting revealed phosphorylation changes in AKT and 70S6K. Changes in the Endocytosis pathway involved genes related to clathrin-mediated endocytosis (dynamin and clathrin). Endocytosis is required for receptor recycling, is involved in Aβ metabolism, and is regulated by phosphatidylinositol signaling. In summary, these studies demonstrate altered genes expression in three SAMP8 hippocampal pathways associated with memory formation and consolidation. These pathways may provide new therapeutic targets in addition to targeting Aβ metabolism itself. Global differential profiling of hippocampal gene expression (4 month and 12 month old SAMP8 and Control mice) was performed using Affymetrix GeneChip® Mouse Genome 430 2.0 Arrays. At 12 months, but not at 4 months, pathway analysis revealed significant differences in the Long Term Potentiation (LTP) (6 genes), Phosphatidylinositol Signaling (6 genes), and Endocytosis (10 genes) pathways. The changes in LTP included MAPK signaling (N-ras, CREB binding protein, protein phosphatase inhibitor 1) and Ca-dependent signaling (PI receptors 1 and 2 and phospholipase C). Changes in phosphatidylinositol signaling genes suggested altered signaling through PI3-kinase, and Western blotting revealed phosphorylation changes in AKT and 70S6K. Changes in the Endocytosis pathway involved genes related to clathrin-mediated endocytosis (dynamin and clathrin). Endocytosis is required for receptor recycling, is involved in Aβ metabolism, and is regulated by phosphatidylinositol signaling. In summary, these studies demonstrate altered genes expression in three SAMP8 hippocampal pathways associated with memory formation and consolidation. These pathways may provide new therapeutic targets in addition to targeting Aβ metabolism itself.
2013-08-30 | GSE49699 | GEO
Project description:Endocytosis controls the perception of stimuli by modulating protein abundance at the plasma membrane. In plants, clathrin-mediated endocytosis is the most prominent internalization pathway and relies on two multimeric adaptor complexes, the AP-2 and the TPLATE complex (TPC). Ubiquitination is a well-established modification triggering endocytosis of cargo proteins, but how this modification is recognized to initiate the endocytic event remains elusive. Here, we show that TASH3, one of the large subunits of TPC, recognizes ubiquitinated cargo at the plasma membrane via its SH3 domain-containing appendage. TASH3 lacking this evolutionary specific appendage modification allows TPC formation, but the plants show severely reduced endocytic densities, which correlates with reduced endocytic flux. Moreover, comparative plasma membrane proteomics identified differential accumulation of multiple ubiquitinated cargo proteins for which we confirm altered trafficking. Our findings position TPC as a key player for ubiquitinated cargo internalization, allowing future identification of target proteins under specific stress conditions.
2023-03-11 | PXD035444 | Pride