lysosome function
Dotaz
Zobrazit nápovědu
790 s. : il.
Although several nanomedicines got clinical approval over the past two decades, the clinical translation rate is relatively small so far. There are many post-surveillance withdrawals of nanomedicines caused by various safety issues. For successful clinical advancement of nanotechnology, it is of unmet need to realize cellular and molecular foundation of nanotoxicity. Current data suggest that lysosomal dysfunction caused by nanoparticles is emerging as the most common intracellular trigger of nanotoxicity. This review analyzes prospect mechanisms of lysosomal dysfunction-mediated toxicity induced by nanoparticles. We summarized and critically assessed adverse drug reactions of current clinically approved nanomedicines. Importantly, we show that physicochemical properties have great impact on nanoparticles interaction with cells, excretion route and kinetics, and subsequently on toxicity. We analyzed literature on adverse reactions of current nanomedicines and hypothesized that adverse reactions might be linked with lysosomal dysfunction caused by nanomedicines. Finally, from our analysis it becomes clear that it is unjustifiable to generalize safety and toxicity of nanoparticles, since different particles possess distinct toxicological properties. We propose that the biological mechanism of the disease progression and treatment should be central in the optimization of nanoparticle design.
- MeSH
- lidé MeSH
- lyzozomy MeSH
- nanočástice * toxicita chemie MeSH
- nanomedicína * metody MeSH
- nanotechnologie metody MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
- MeSH
- centrální nervový systém cytologie MeSH
- fenobarbital farmakologie MeSH
- Haplorrhini MeSH
- králíci MeSH
- krysa rodu rattus MeSH
- lyzozomy účinky léků MeSH
- neurony účinky léků MeSH
- psi MeSH
- železo-dextranový komplex farmakologie MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- krysa rodu rattus MeSH
- psi MeSH
- zvířata MeSH
In the ciliate Tetrahymena thermophila, lysosome-related organelles called mucocysts accumulate at the cell periphery where they secrete their contents in response to extracellular events, a phenomenon called regulated exocytosis. The molecular bases underlying regulated exocytosis have been extensively described in animals but it is not clear whether similar mechanisms exist in ciliates or their sister lineage, the Apicomplexan parasites, which together belong to the ecologically and medically important superphylum Alveolata. Beginning with a T. thermophila mutant in mucocyst exocytosis, we used a forward genetic approach to uncover MDL1 (Mucocyst Discharge with a LamG domain), a novel gene that is essential for regulated exocytosis of mucocysts. Mdl1p is a 40 kDa membrane glycoprotein that localizes to mucocysts, and specifically to a tip domain that contacts the plasma membrane when the mucocyst is docked. This sub-localization of Mdl1p, which occurs prior to docking, underscores a functional asymmetry in mucocysts that is strikingly similar to that of highly polarized secretory organelles in other Alveolates. A mis-sense mutation in the LamG domain results in mucocysts that dock but only undergo inefficient exocytosis. In contrast, complete knockout of MDL1 largely prevents mucocyst docking itself. Mdl1p is physically associated with 9 other proteins, all of them novel and largely restricted to Alveolates, and sedimentation analysis supports the idea that they form a large complex. Analysis of three other members of this putative complex, called MDD (for Mucocyst Docking and Discharge), shows that they also localize to mucocysts. Negative staining of purified MDD complexes revealed distinct particles with a central channel. Our results uncover a novel macromolecular complex whose subunits are conserved within alveolates but not in other lineages, that is essential for regulated exocytosis in T. thermophila.
- MeSH
- exocytóza genetika MeSH
- lyzozomy metabolismus MeSH
- organely metabolismus MeSH
- sekreční vezikuly genetika metabolismus MeSH
- Tetrahymena thermophila * genetika MeSH
- Tetrahymena * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
A neuropathologic study of three cases of prosaposin (pSap) deficiency (ages at death 27, 89 and 119 days), carried out in the standard autopsy tissues, revealed a neurolysosomal pathology different from that in the non-neuronal cells. Non-neuronal storage is represented by massive lysosomal accumulation of glycosphingolipids (glucosyl-, galactosyl-, lactosyl-, globotriaosylceramides, sulphatide, and ceramide). The lysosomes in the central and peripheral neurons were distended by pleomorphic non-lipid aggregates lacking specific staining and autofluorescence. Lipid storage was borderline in case 1, and at a low level in the other cases. Neurolysosomal storage was associated with massive ubiquitination, which was absent in the non-neuronal cells and which did not display any immunohistochemical aggresomal properties. Confocal microscopy and cross-correlation function analyses revealed a positive correlation between the ubiquitin signal and the late endosomal/lysosomal markers. We suppose that the neuropathology most probably reflects excessive influx of non-lipid material (either in bulk or as individual molecules) into the neurolysosomes. The cortical neurons appeared to be uniquely vulnerable to pSap deficiency. Whereas in case 1 they populated the cortex, in cases 2 and 3 they had been replaced by dense populations of both phagocytic microglia and astrocytes. We suggest that this massive neuronal loss reflects a cortical neuronal survival crisis precipitated by the lack of pSap. The results of our study may extend the knowledge of the neurotrophic function of pSap, which should be considered essential for the survival and maintenance of human cortical neurons.
- MeSH
- antigeny diferenciační myelomonocytární metabolismus MeSH
- CD antigeny metabolismus MeSH
- dítě MeSH
- financování organizované MeSH
- gliový fibrilární kyselý protein metabolismus MeSH
- glykosfingolipidy metabolismus MeSH
- lidé MeSH
- lyzozomální nemoci z ukládání metabolismus patologie MeSH
- lyzozomy metabolismus patologie MeSH
- molekuly buněčné adheze neuronové metabolismus MeSH
- mozková kůra patologie MeSH
- neurony patologie ultrastruktura MeSH
- novorozenec MeSH
- pitva MeSH
- saposiny fyziologie nedostatek MeSH
- ubikvitin metabolismus MeSH
- Check Tag
- dítě MeSH
- lidé MeSH
- mužské pohlaví MeSH
- novorozenec MeSH
- Publikační typ
- kazuistiky MeSH
To examine reciprocal or unilateral implications between two cell destruction processes, autophagy and apoptosis, in 5-Fluorouracil (5-FU)-treated tumor cells, a combination of chemical inhibitors, RNAi and genetic approaches were used. In contrast to cancer cells harboring obstructed apoptosis, either at the DISC or the mitochondrial level, p53-deficiency generated signs of autophagy deregulation upon chemotherapy. On the other, hand disruption of lysosomal function by chloroquine, caused a profound decrease in apoptotic markers appearing in response to 5-FU. DR5, which is essential for 5-FU-induced apoptosis, accumulated in lysosomes and autophagosomes upon chloroquine treatment. Since neither 3-MA, RNAi of critical autophagy regulators or inhibition of cathepsins reversed apoptosis in a similar manner, it is likely that not autophagy per se but rather correct receptor transport is an important factor for 5-FU cytotoxicity. We found that apoptosis generated by TRAIL, the cognate ligand for DR5, remained unchanged upon chloroquine lysosomal interference, indicating that 5-FU activates the receptor by a discrete mechanism. In support, depletion of membrane cholesterol or hampering cholesterol transport drastically reduced 5-FU cytotoxicity. We conclude that targeting of lysosomes by chloroquine deregulates DR5 trafficking and abrogates 5-FU- but not TRAIL-stimulated cell elimination, hence suggesting a novel mechanism for receptor activation.
- MeSH
- apoptóza MeSH
- autofagie * MeSH
- buněčná membrána metabolismus MeSH
- chlorochin chemie MeSH
- cholesterol chemie MeSH
- fagozomy MeSH
- fluoruracil chemie MeSH
- HCT116 buňky MeSH
- lidé MeSH
- ligandy MeSH
- lyzozomy metabolismus MeSH
- makrolidy chemie MeSH
- mitochondrie metabolismus MeSH
- nádorový supresorový protein p53 metabolismus MeSH
- protein TRAIL farmakologie MeSH
- protinádorové antimetabolity farmakologie MeSH
- RNA interference MeSH
- signální transdukce účinky léků MeSH
- TRAIL receptory metabolismus MeSH
- transport proteinů MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Farber disease (FD) is a debilitating lysosomal storage disorder (LSD) caused by a deficiency of acid ceramidase (ACDase) activity due to mutations in the gene ASAH1. Patients with ACDase deficiency may develop a spectrum of clinical phenotypes. Severe cases of FD are frequently associated with neurological involvement, failure to thrive, and respiratory complications. Mice homozygous ( Asah1P361R/P361R) for an orthologous patient mutation in Asah1 recapitulate human FD. In this study, we show significant impairment in lung function, including low compliance and increased airway resistance in a mouse model of ACDase deficiency. Impaired lung mechanics in Farber mice resulted in decreased blood oxygenation and increased red blood cell production. Inflammatory cells were recruited to both perivascular and peribronchial areas of the lung. We observed large vacuolated foamy histiocytes that were full of storage material. An increase in vascular permeability led to protein leakage, edema, and impacted surfactant homeostasis in the lungs of Asah1P361R/P361R mice. Bronchial alveolar lavage fluid (BALF) extraction and analysis revealed accumulation of a highly turbid lipoprotein-like substance that was composed in part of surfactants, phospholipids, and ceramides. The phospholipid composition of BALF from Asah1P361R/P361R mice was severely altered, with an increase in both phosphatidylethanolamine (PE) and sphingomyelin (SM). Ceramides were also found at significantly higher levels in both BALF and lung tissue from Asah1P361R/P361R mice when compared with levels from wild-type animals. We demonstrate that a deficiency in ACDase leads to sphingolipid and phospholipid imbalance, chronic lung injury caused by significant inflammation, and increased vascular permeability, leading to impaired lung function.
- MeSH
- bronchoalveolární lavážní tekutina MeSH
- ceramidy metabolismus MeSH
- fenotyp MeSH
- fosfolipidy metabolismus MeSH
- homozygot MeSH
- kyselá ceramidasa fyziologie MeSH
- modely nemocí na zvířatech * MeSH
- myši knockoutované MeSH
- myši MeSH
- plíce metabolismus patologie MeSH
- poškození plic etiologie metabolismus patologie MeSH
- respirační funkční testy MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The lysosome represents a central degradative compartment of eukaryote cells, yet little is known about the biogenesis and function of this organelle in parasitic protists. Whereas the mannose 6-phosphate (M6P)-dependent system is dominant for lysosomal targeting in metazoans, oligosaccharide-independent sorting has been reported in other eukaryotes. In this study, we investigated the phagolysosomal proteome of the human parasite Trichomonas vaginalis, its protein targeting and the involvement of lysosomes in hydrolase secretion. The organelles were purified using Percoll and OptiPrep gradient centrifugation and a novel purification protocol based on the phagocytosis of lactoferrin-covered magnetic nanoparticles. The analysis resulted in a lysosomal proteome of 462 proteins, which were sorted into 21 classes. Hydrolases represented the largest functional class and included proteases, lipases, phosphatases, and glycosidases. Identification of a large set of proteins involved in vesicular trafficking (80) and turnover of actin cytoskeleton rearrangement (29) indicate a dynamic phagolysosomal compartment. Several cysteine proteases such as TvCP2 were previously shown to be secreted. Our experiments showed that secretion of TvCP2 was strongly inhibited by chloroquine, which increases intralysosomal pH, thus indicating that TvCP2 secretion occurs through lysosomes rather than the classical secretory pathway. Unexpectedly, we identified divergent homologues of the M6P receptor TvMPR in the phagolysosomal proteome, although T. vaginalis lacks enzymes for M6P formation. To test whether oligosaccharides are involved in lysosomal targeting, we selected the lysosome-resident cysteine protease CLCP, which possesses two glycosylation sites. Mutation of any of the sites redirected CLCP to the secretory pathway. Similarly, the introduction of glycosylation sites to secreted β-amylase redirected this protein to lysosomes. Thus, unlike other parasitic protists, T. vaginalis seems to utilize glycosylation as a recognition marker for lysosomal hydrolases. Our findings provide the first insight into the complexity of T. vaginalis phagolysosomes, their biogenesis, and role in the unconventional secretion of cysteine peptidases.
- MeSH
- cystein metabolismus MeSH
- cysteinové proteasy * metabolismus MeSH
- fagozomy metabolismus MeSH
- lidé MeSH
- lyzozomy metabolismus MeSH
- proteasy metabolismus MeSH
- proteomika MeSH
- Trichomonas vaginalis * metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
OBJECTIVES: The majority of people with suspected genetic dystonia remain undiagnosed after maximal investigation, implying that a number of causative genes have not yet been recognized. We aimed to investigate this paucity of diagnoses. METHODS: We undertook weighted burden analysis of whole-exome sequencing (WES) data from 138 individuals with unresolved generalized dystonia of suspected genetic etiology, followed by additional case-finding from international databases, first for the gene implicated by the burden analysis (VPS16), and then for other functionally related genes. Electron microscopy was performed on patient-derived cells. RESULTS: Analysis revealed a significant burden for VPS16 (Fisher's exact test p value, 6.9 × 109 ). VPS16 encodes a subunit of the homotypic fusion and vacuole protein sorting (HOPS) complex, which plays a key role in autophagosome-lysosome fusion. A total of 18 individuals harboring heterozygous loss-of-function VPS16 variants, and one with a microdeletion, were identified. These individuals experienced early onset progressive dystonia with predominant cervical, bulbar, orofacial, and upper limb involvement. Some patients had a more complex phenotype with additional neuropsychiatric and/or developmental comorbidities. We also identified biallelic loss-of-function variants in VPS41, another HOPS-complex encoding gene, in an individual with infantile-onset generalized dystonia. Electron microscopy of patient-derived lymphocytes and fibroblasts from both patients with VPS16 and VPS41 showed vacuolar abnormalities suggestive of impaired lysosomal function. INTERPRETATION: Our study strongly supports a role for HOPS complex dysfunction in the pathogenesis of dystonia, although variants in different subunits display different phenotypic and inheritance characteristics. ANN NEUROL 2020;88:867-877.
- MeSH
- dospělí MeSH
- dystonie genetika patologie MeSH
- exom genetika MeSH
- fibroblasty patologie MeSH
- genetická predispozice k nemoci genetika MeSH
- genetická variace MeSH
- lidé středního věku MeSH
- lidé MeSH
- lyzozomální nemoci z ukládání genetika patologie MeSH
- mutace genetika MeSH
- osobní újma zaviněná nemocí MeSH
- rodokmen MeSH
- vezikulární transportní proteiny genetika MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Lysosomes, now known to take part in multiple cellular functions, also respond to various stress stimuli. These include biogenesis in response to nanomolar concentrations of hydrophobic weak-base anticancer drugs. However, since lysosomal stress mediated by accumulation of weak-base drugs at such concentrations has never been proven and these drugs have diverse effects on malignant cells, we investigated whether the interpretation of the data was true. We found that lysosomal accumulation of the drugs daunorubicin, doxorubicin, mitoxantrone, symadex, chloroquine, clomipramine and sunitinib alone, was insufficient to induce lysosomal alkalization i.e., lysosomal stress-mediated biogenesis at nanomolar concentrations. Instead, we found that some of the drugs used induced G2 phase arrest and lysosomal biogenesis that is associated with activation of transcription factor EB (TFEB). Similarly, cantharidin, a control compound that does not belong to the weak base drugs, induced cell cycle arrest in the G2 phase associated with TFEB-driven lysosomal biogenesis. Overall none of the tested drugs caused stress-induced lysosomal biogenesis at nanomolar concentrations. However, daunorubicin, doxorubicin, mitoxantrone, symadex and cantharidin induced a massive block in the G2 phase of the cell cycle which is naturally associated with TFEB-driven lysosomal biogenesis.
