A lysosome-plasma membrane-sphingolipid axis linking lysosomal storage to cell growth arrest
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ABSTRACT:
PROVIDER: PRJNA418450 | ENA |
REPOSITORIES: ENA
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Project description:We used human fibroblasts loaded with sucrose as a simple model of lysosomal accumulation, and we verified by high-throughput RNA sequencing which processes were altered by the treatment at two different time points. Moreover, we hypothesized that ceramide production due to the ectopic catabolism of plasma-membrane glycosphingolipids is involved in cell cycle arrest upon sucrose treatment. To test this hypothesis, we treated sucrose-loaded fibroblasts with two specific inhibitors for the β-glucosidases GBA1 and GBA2, and analyzed the cell responses using high-throughput RNA sequence.
2019-11-06 | GSE106928 | GEO
Project description: Not available
| S-EPMC6133699 | biostudies-literature
Project description:HDL particles are known to possess several anti-atherogenic properties that include the removal of excess cholesterol from peripheral tissues, the maintenance of endothelial integrity, antioxidant and antiinflammatory activities. ApoA-I overexpression in apoE-deficient (EKO) mice has been shown to increase HDL levels and to strongly reduce atherosclerosis development. The aim of the study was to investigate gene expression patterns associated with atherosclerosis development in the aorta of EKO mice and how HDL plasma levels relate to gene expression patterns at different stages of atherosclerosis development and with different dietary treatments. Methods Eight weeks old EKO mice, EKO mice overexpressing human apoA-I (EKO/hA-I) and wild-type mice as controls were fed either Chow or Western diet for 6 or 22 weeks. Cholesterol distribution among lipoproteins was evaluated and atherosclerosis of the aorta was quantified. High-throughput sequencing technologies were used to analyse the transcriptome of the aorta of the three genotypes in each experimental condition. Results: In addition to the well-known activation of inflammation and immune response, the impairment of sphingolipid metabolism, phagosome-lysosome system and osteoclast differentiation emerged as relevant players in atherosclerosis development. The reduced atherosclerotic burden in the aorta of EKO mice expressing high levels of apoA-I was accompanied by a reduced activation of the immune system markers, as well as reduced perturbation of lysosomal activity and a better regulation of the sphingolipid synthesis pathway Conclusions. ApoA-I modulates atherosclerosis development in the aorta of EKO mice affecting the expression of pathways additional to those associated with inflammation and immune response
2020-12-22 | GSE163657 | GEO
Project description:Despite accumulating evidences linking defective lysosome function with autoimmune diseases, how the catabolic machinery is regulated for immune homeostasis remains largely unknown. Lamtor5 is a subunit of the Ragulator mediating mTORC1 activation in response to amino acids, but its action mode and physiological role are yet to be addressed. Here we unexpectedly found that myeloid Lamtor5 ablating mice developed spontaneous inflammation and systemic lupus erythematosus (SLE)-like manifestation. Loss of Lamtor5 in macrophages caused impaired vacuolar H⁺-ATPase (v-ATPase) activity, lysosome de-acidification, and aberrant mTORC1 activation, correlating with undesirable inflammatory responses. Mechanistically, we showed that Lamtor5 physically associated with ATP6V1A, an essential subunit of v-ATPase, and promoted the V0/V1 holoenzyme assembly for lysosome acidification. Notably, binding of Lamtor5 to v-ATPase substantially affected lysosomal tethering of Rag GTPase and weakened its interaction with mTORC1 for activation. Importantly, defective Lamtor5 expression, along with impaired lysosomal function and hyperactivation of mTORC1, was corroborated in peripheral blood mononuclear cells (PBMCs) of SLE patients and correlated with disease severity. Overall, our findings establish Lamtor5 as a new lysosome regulator, and elucidate an unappreciated mechanism that coordinates catabolic and anabolic pathways to bolster immune homeostasis preventing autoimmunity.
2024-03-03 | GSE227039 | GEO
Project description:Lysosomal cathepsins regulate an exquisite range of biological functions, and their deregulation is associated with inflammatory, metabolic and degenerative disease in humans. Here, we identified a key cell-intrinsic role for cathepsin B as a negative feedback regulator of lysosomal biogenesis and autophagy. Mice and macrophages lacking cathepsin B activity had increased resistance to the cytosolic bacterial pathogen Francisella novicida. Genetic deletion or pharmacological inhibition of cathepsin B downregulated mTOR activity and prevented cleavage of the lysosomal calcium channel TRPML1. These events drove transcription of lysosomal and autophagy genes via the transcription factor TFEB, which increased lysosomal biogenesis and activation of autophagy-initiation kinase ULK1 for clearance of the bacteria. Our results identified a fundamental biological function of cathepsin B in providing a checkpoint for homeostatic maintenance of lysosome population and basic recycling functions in the cell. We used microarrays to explore the gene expression profiles differentially expressed in bone marrow-derived macrophages (BMDM) isolated from cathepsin B-/- and wild-type mice.
2016-08-04 | E-GEOD-79508 | biostudies-arrayexpress
Project description:Lysosomal dysfunction is considered pathogenic in Alzheimer Disease (AD). Loss of Presenilin-1(PSEN1) function causing early onset AD impedes acidification via defective vATPase V0a1 subunit delivery to lysosomes. We report that isoproterenol and related β2-adrenergic agonists re-acidify lysosomes in PSEN1 KO cells and fibroblasts from PSEN1 familial AD(FAD) patients, restores lysosomal calcium homeostasis and proteolysis, and reverses impaired autophagy flux. We identify a novel rescue mechanism involving PKA-mediated facilitated delivery of ClC-7 to lysosomes, which stimulates chloride influx and reverses markedly lowered Cl- content of PSEN1 KO lysosomes. Notably, PSEN1 loss-of-function impedes ER-to-lysosome delivery of ClC-7, thus accounting for lysosomal Cl- deficits that compound pH deficits due to deficient vATPase function. Transcriptomics of PSEN1-deficient cells reveal strongly down-regulated ER-to-lysosome transport pathways and reversibility by isoproterenol. Our findings uncover a broadened PSEN1 role in lysosomal ion homeostasis and novel pH modulation of lysosomes through β-adrenergic regulation of ClC-7, which can be therapeutically modulated.
2020-02-29 | GSE136894 | GEO
Project description:The evolutionarily conserved serine/threonine kinase mTORC1 is a central regulator of cell growth and proliferation. mTORC1 is activated on the lysosome surface. However, once mTORC1 is activated, it is unclear whether mTORC1 phosphorylates local lysosomal proteins to regulate specific aspects of lysosomal biology. By integrating analyses of lysosome proteome with mTORC1-regulated phosphoproteome, we identify STK11IP as a lysosome-specific substrate of mTORC1. mTORC1 phosphorylates STK11IP at S404. Knockout of STK11IP leads to a robust increase of autophagy flux. Dephosphorylation of STK11IP at S404 represses the role of STK11IP as an autophagy inhibitor. Mechanistically, STK11IP binds to V-ATPase, and regulates the activity of V-ATPase. Knockout of STK11IP protects mice from fasting or Methionine/Choline-Deficient Diet diet-induced fatty liver. Thus, our study demonstrates that STK11IP phosphorylation represents a novel mechanism for mTORC1 to regulate lysosomal acidification and autophagy, and points to STK11IP as a promising therapeutic target for the amelioration of diseases with aberrant autophagy signaling.
2022-05-20 | PXD031543 | Pride
Project description:Lysosome plays important roles in cellular homeostasis and its dysregulation is associated with cancer. However, the regulation and underlying mechanism of lysosome in cancer survival remain incompletely understood. Here, we reveal a role for a histone acetylation-regulated long non-coding RNA termed as lysosome cell death regulator (LCDR) in lung cancer cell survival, knockdown of which promotes apoptosis. Mechanistically, LCDR binds to heterogenous nuclear ribonucleoprotein K (hnRNP K) to regulate the stability of lysosomal-associated protein transmembrane 5 (LAPTM5) transcript that maintain integrity of lysosomal membrane. Consequently, knockdown of LCDR, hnRNP K or LAPTM5 promotes lysosomal membrane permeabilization and lysosomal cell death-mediated apoptosis. LAPTM5 overexpression or cathepsin B inhibitor partially restores the effects of this axis on lysosomal cell death. Clinically, LCDR/hnRNP K/LAPTM5 are upregulated in lung cancer tissues and coexpression of this axis shows the increased diagnostic value for lung cancer. These findings shed light on LCDR/hnRNP K/LAPTM5 as potential therapeutic targets and targeting lysosome is a promising strategy in cancer treatment.
2021-05-05 | GSE173849 | GEO
Project description:Acute lysosomal membrane damage reduces the cellular population of functional lysosomes. However, these damaged lysosomes have a remarkable recovery potential independent of lysosomal biogenesis and remain unaffected in TFEB/TFE3-depleted cells. We combined proximity labelling based proteomics, biochemistry and high-resolution microscopy to unravel a new lysosomal membrane regeneration pathway which is dependent on ATG8, lysosomal membrane protein LIMP2, the Rab7 GAP TBC1D15, and proteins required for autophagic lysosomal reformation (ALR) including Dynamin2, Kinesin5B and Clathrin. Upon lysosomal damage, LIMP2 act as a lysophagy receptor to bind ATG8, which in turn recruits TBC1D15 to damaged membranes. TBC1D15 hydrolyses Rab7-GTP to segregate the damaged lysosomal mass and provides a scaffold to assemble and stabilize the ALR machinery, potentiating the formation of lysosomal tubulesand subsequent Dynamin2-dependent scission. TBC1D15-mediated lysosome regeneration was also observed in a cell culture model of oxalate nephropathy.
2023-03-07 | PXD040191 | Pride
Project description:Mycobacterium tuberculosis (Mtb) infects multiple lung myeloid cell subsets and persists despite innate and adaptive immune responses. However, the mechanisms allowing Mtb to evade elimination by these subsets are not fully understood. Here, we determined that four weeks post infection, after development of adaptive immune responses, CD11clo monocyte-derived lung cells termed MNC1 (mononuclear cell subset 1), harbor more live Mtb compared to alveolar macrophages (AM), neutrophils, and less permissive CD11chi MNC2. Bulk RNA-seq analysis for these subsets identified that lysosome biogenesis pathway is underexpressed in MNC1. Functional assays confirmed that Mtb-permissive MNC1 are deficient in lysosome content, lysosomal acidification, and lysosomal activity compared to AM, and have less nuclear TFEB, a master regulator of lysosome biogenesis. Mtb infection does not alter lysosome deficiency in MNC1. Instead, Mtb recruits MNC1 and MNC2 to the lungs for its spread from AM to these subsets, which depend on Mtb ESX-1 secretion system. Furthermore, nilotinib-mediated TFEB activation enhances lysosome function of primary macrophages in vitro, and MNC1 and MNC2 in vivo, improving control of Mtb infection. Our results suggest that Mtb exploits lysosome-poor monocyte-derived lung cells for persistence; targeting lysosome biogenesis may be an effective approach to host-directed therapy for tuberculosis, enabling permissive lung cells to restrict and kill Mtb through autophagy and other mechanisms.
2023-02-08 | GSE220147 | GEO