Lysosomal Storage Causes Cellular Dysfunction in Mucolipidosis II Skin Fibroblasts

Otomo, Takanobu; Higaki, Kazutaka; Nanba, Eiji; Ozono, Keiichi; Sakai, Norio

doi:10.1074/jbc.m111.267930

Cited by 37 publications

(29 citation statements)

References 31 publications

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“…The presence of PRP might have induced perturbations in cell metabolism because of anoikis triggered by the loss or changes in the anchoring and autophagic impairment that induce EMT [22]. We, therefore, investigated the possible increase in the amount of lysosomes that leads to the accumulation of aberrant mitochondria and its association with phenotype transition [23]. The amounts of lysosome and mitochondria were increased in stromal cells from phyllodes tumor as observed using LysoTracker and mitoTracker staining (Figure 2G and 2H).…”

Section: Resultsmentioning

confidence: 99%

Interface between breast cancer cells and the tumor microenvironment using platelet-rich plasma to promote tumor angiogenesis - influence of platelets and fibrin bundles on the behavior of breast tumor cells

et al. 2017

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Cancer progression is associated with an evolving tissue interface of direct epithelial-tumor microenvironment interactions. In biopsies of human breast tumors, extensive alterations in molecular pathways are correlated with cancer staging on both sides of the tumor-stroma interface. These interactions provide a pivotal paracrine signaling to induce malignant phenotype transition, the epithelial-mesenchymal transition (EMT). We explored how the direct contact between platelets-fibrin bundles primes metastasis using platelet-rich plasma (PRP) as a source of growth factors and mimics the provisional fibrin matrix between actively growing breast cancer cells and the tumor stroma. We have demonstrated PRP functions, modulating cell proliferation that is tumor-subtype and cancer cell-type-specific. Epithelial and stromal primary cells were prepared from breast cancer biopsies from 21 women with different cancer subtypes. Cells supplemented with PRP were immunoblotted with anti-phospho and total Src-Tyr-416, FAK-Try-925, E-cadherin, N-cadherin, TGF-β, Smad2, and Snail monoclonal antibodies. Breast tumor cells from luminal B and HER2 subtypes showed the most malignant profiles and the expression of thrombin and other classes of proteases at levels that were detectable through FRET peptide libraries. The angiogenesis process was investigated in the interface obtained between platelet-fibrin-breast tumor cells co-cultured with HUVEC cells. Luminal B and HER2 cells showed robust endothelial cell capillary-like tubes ex vivo. The studied interface contributes to the attachment of endothelial cells, provides a source of growth factors, and is a solid substrate. Thus, replacement of FBS supplementation with PRP supplementation represents an efficient and simple approach for mimicking the real multifactorial tumor microenvironment.

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Section: Resultsmentioning

confidence: 99%

Interface between breast cancer cells and the tumor microenvironment using platelet-rich plasma to promote tumor angiogenesis - influence of platelets and fibrin bundles on the behavior of breast tumor cells

et al. 2017

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“…Activities of lysosomal acid hydrolases were measured using 4‐methylumbelliferyl (4‐MU) substrates (Otomo et al , ). Cell lysates were prepared by sonication in water and determined protein concentration by Bradford protein assay kit (Bio‐Rad) according to manufacturer's protocol.…”

Section: Methodsmentioning

confidence: 99%

Autophagosome–lysosome fusion in neurons requires INPP 5E, a protein associated with Joubert syndrome

et al. 2016

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Autophagy is a multistep membrane traffic pathway. In contrast to autophagosome formation, the mechanisms underlying autophagosome-lysosome fusion remain largely unknown. Here, we describe a novel autophagy regulator, inositol polyphosphate-5-phosphatase E (INPP5E), involved in autophagosome-lysosome fusion process. In neuronal cells, INPP5E knockdown strongly inhibited autophagy by impairing the fusion step. A fraction of INPP5E is localized to lysosomes, and its membrane anchoring and enzymatic activity are necessary for autophagy. INPP5E decreases lysosomal phosphatidylinositol 3,5-bisphosphate (PI(3,5)P 2 ), one of the substrates of the phosphatase, that counteracts cortactinmediated actin filament stabilization on lysosomes. Lysosomes require actin filaments on their surface for fusing with autophagosomes. INPP5E is one of the genes responsible for Joubert syndrome, a rare brain abnormality, and mutations found in patients with this disease caused defects in autophagy. Taken together, our data reveal a novel role of phosphoinositide on lysosomes and an association between autophagy and neuronal disease.

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“…When cells are depleted of sterols, the complex dissociates and exposes a Golgi sorting signal, which allows the ER exit of SREBP/SCAP complexes, and subsequent fi rst cleavage of SREBPs by S1P ( 29,30 ). Here we examined whether the transport of the GlcNAc-1-phosphotransferase ␣ / ␤ -subunit precursor from the ER to the Golgi apparatus is also regulated by the intracellular sterol content because the loss of GlcNAc-1-phosphotransferase activity is associated with accumulation of cholesterol (16)(17)(18). We demonstrated, however, that neither the induced reduction of the cholesterol content by the HMG-CoA reductase inhibitor atorvastatin nor the LDL-mediated MLII MEFs ( Fig.…”

Section: Discussionmentioning

confidence: 99%

“…MLII (also called I-cell disease) is a severe multisystemic inherited disorder of childhood caused by mutations in the GNPTAB gene encoding the ␣ / ␤ -subunit precursor protein of the GlcNAc-1-phosphotransferase ( 6,15 ). Although the nature of storage material in MLII cells and tissues has not been fully characterized, analysis of fibroblasts of MLII patients and MLII mice revealed, in addition to increased levels of phospholipids, fucosylated oligosaccharides, and sialic acid-containing glycosphingolipids, an elevation and lysosomal accumulation of cholesterol (16)(17)(18).…”

Section: Mrna Analysismentioning

confidence: 99%

Site-1 protease-activated formation of lysosomal targeting motifs is independent of the lipogenic transcription control

Klünder

Heeren

Markmann

et al. 2015

Journal of Lipid Research

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endocytosis, autophagy, and phagocytosis through the concerted action of more than 50 acid hydrolases ( 1 ). To maintain their function, lysosomes require a continuous replenishment of newly synthesized components transported from the endoplasmic reticulum (ER) via the Golgi apparatus to the endosomal/lysosomal compartment. The effi cient transport of soluble lysosomal enzymes to lysosomes requires mannose 6-phosphate (M6P) residues on their N -linked glycans, which serve as recognition markers for M6P-specifi c receptors (MPRs) ( 2 ). The formation of M6P residues is catalyzed by two enzymes, the N -acetylglucosamine-1-phosphotransferase (termed "GlcNAc-1-phosphotransferase") and the GlcNAc-1-phosphodiester ␣ -N -acetylglucosaminidase (termed "uncovering enzyme") localized in the cis -Golgi apparatus and trans -Golgi network, respectively ( 3 ).The GlcNAc-1-phosphotransferase is a heterohexameric complex of three subunits ( ␣ 2 ␤ 2 ␥ 2 ), which are encoded by two genes ( 4-6 ). The ␣ -and ␤ -subunits of the GlcNAc-1-phosphotransferase are synthesized in the ER as a single, highly N -glycosylated, 190 kDa, type III membrane protein ( 6 ). For the transport to the Golgi apparatus, combinatorial dileucine and dibasic sorting motifs in the N-and C-terminal cytosolic domains, respectively, are required ( 7 ). Upon arrival in the cis -Golgi compartment, the ␣ / ␤ -subunit precursor is proteolytically cleaved by the site-1 protease (S1P) into mature ␣ -and ␤ -subunits ( 8 ), which are prerequisite for the enzymatic activity of the GlcNAc-1-phosphotransferase complex ( 9 ).Abstract Site-1 protease (S1P) cleaves membrane-bound lipogenic sterol regulatory element-binding proteins (SREBPs) and the ␣ / ␤ -subunit precursor protein of the N -acetylglucosamine-1-phosphotransferase forming mannose 6-phosphate (M6P) targeting markers on lysosomal enzymes. The translocation of SREBPs from the endoplasmic reticulum (ER) to the Golgi-resident S1P depends on the intracellular sterol content, but it is unknown whether the ER exit of the ␣ / ␤ -subunit precursor is regulated. Here, we investigated the effect of cholesterol depletion (atorvastatin treatment) and elevation (LDL overload) on ER-Golgi transport, S1P-mediated cleavage of the ␣ / ␤ -subunit precursor, and the subsequent targeting of lysosomal enzymes along the biosynthetic and endocytic pathway to lysosomes. The data showed that the proteolytic cleavage of the ␣ / ␤ -subunit precursor into mature and enzymatically active subunits does not depend on the cholesterol content. In either treatment, lysosomal enzymes are normally decorated with M6P residues, allowing the proper sorting to lysosomes. In addition, we found that, in fi broblasts of mucolipidosis type II mice and Niemann-Pick type C patients characterized by aberrant cholesterol accumulation, the proteolytic cleavage of the ␣ / ␤ -subunit precursor was not impaired. We conclude that S1P substrate-dependent regulatory mechanisms for lipid synthesis and biogenesis of lysosomes are different. T.B., and S.P.) and GR...

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Lysosomal Storage Causes Cellular Dysfunction in Mucolipidosis II Skin Fibroblasts

Cited by 37 publications

References 31 publications

Interface between breast cancer cells and the tumor microenvironment using platelet-rich plasma to promote tumor angiogenesis - influence of platelets and fibrin bundles on the behavior of breast tumor cells

Interface between breast cancer cells and the tumor microenvironment using platelet-rich plasma to promote tumor angiogenesis - influence of platelets and fibrin bundles on the behavior of breast tumor cells

Autophagosome–lysosome fusion in neurons requires INPP 5E, a protein associated with Joubert syndrome

Site-1 protease-activated formation of lysosomal targeting motifs is independent of the lipogenic transcription control

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