scholarly journals Lysosomal storage disorders: The cellular impact of lysosomal dysfunction

2012 ◽  
Vol 199 (5) ◽  
pp. 723-734 ◽  
Author(s):  
Frances M. Platt ◽  
Barry Boland ◽  
Aarnoud C. van der Spoel
Keyword(s):  
Lysosomal Enzymes ◽  
Gene Mutations ◽  
Lysosomal Storage Diseases ◽  
Lysosomal Storage ◽  
Lysosomal Dysfunction ◽  
Membrane Bound ◽  
Cellular Pathways ◽  
Normal Cellular Function ◽  
Lysosomal Proteins ◽  
Storage Disorders

Lysosomal storage diseases (LSDs) are a family of disorders that result from inherited gene mutations that perturb lysosomal homeostasis. LSDs mainly stem from deficiencies in lysosomal enzymes, but also in some non-enzymatic lysosomal proteins, which lead to abnormal storage of macromolecular substrates. Valuable insights into lysosome functions have emerged from research into these diseases. In addition to primary lysosomal dysfunction, cellular pathways associated with other membrane-bound organelles are perturbed in these disorders. Through selective examples, we illustrate why the term “cellular storage disorders” may be a more appropriate description of these diseases and discuss therapies that can alleviate storage and restore normal cellular function.

Lysosomal Storage Disorders

2021 ◽  
pp. 1106-1113
Author(s):  
Radhika Dhamija ◽  
Erin Conboy ◽  
Lily C. Wong-Kisiel
Keyword(s):  
Lysosomal Storage Diseases ◽  
Lysosomal Storage Disorders ◽  
Lysosomal Storage ◽  
Storage Diseases ◽  
Activator Proteins ◽  
Autophagic Vacuoles ◽  
Enzyme Substrate ◽  
Membrane Bound ◽  
Considerable Morbidity ◽  
Storage Disorders

Lysosomes are membrane-bound organelles that degrade various macromolecules. Lysosomal storage diseases are a clinically, enzymatically, and genetically heterogeneous group of disorders resulting from intracellular accumulation of substrates. Mechanisms of lysosomal storage disorders include 1) primary deficiency of specific hydrolases; 2) defects in activator proteins required for enzyme-substrate interactions in posttranslational modification of enzymes or in transport of the substrate from lysosomes; and 3) abnormalities of fusion between autophagic vacuoles and lysosomes. Substrate accumulation is slowly progressive, leading to considerable morbidity and mortality.

Development and Validation of Leukocyte Enzyme Activity Assay by LC-MS/MS for Diagnosis of Krabbe Disease and Other Lysosomal Storage Diseases

2020 ◽  
Vol 154 (Supplement_1) ◽  
pp. S16-S16
Author(s):  
Hsuan-Chieh Liao ◽  
Laura Mitchell ◽  
Katerina Sadilkova ◽  
Jane Dickerson ◽  
Rhona Jack ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Liquid Chromatography ◽  
Lysosomal Enzymes ◽  
Internal Standard ◽  
Lysosomal Storage Diseases ◽  
Krabbe Disease ◽  
Tandem Mass ◽  
Lysosomal Storage ◽  
Mass Detection ◽  
Storage Diseases

Abstract Background Deficiency of the lysosomal enzyme galactosylcerebrosidase (GALC) causes Krabbe disease. The diagnosis for Krabbe disease includes measurement of GALC enzymatic activity by radioisotope assay or accumulation of metabolite psychosine. To improve current diagnostic workflow and assay performance, we developed and validated a leukocyte enzymatic assay by using liquid chromatography tandem mass spectrometry (LC-MS/MS) for lysosomal storage diseases. Methods Leukocytes were separated and extracted from whole blood samples, and total protein was quantitated by BCA method. Commercialized and multiplexed substrates, internal standards, and buffer were incubated with cell lysates. The lysosomal enzymes in leukocytes metabolized the artificial substrate into product which is structurally identical to the internal standard. Liquid-liquid extraction was performed and supernatant was dried down and reconstituted. Liquid chromatography separation was achieved by Waters CSH C18, 2.1 x 50 mm column and Acquity UPLC system. A Waters Xevo TQS tandem mass spectrometer was used for mass detection. Results Enzymatic reaction products for six lysosomal enzymes were chromatographically resolved from substrate breakdown products through 3.5 minutes gradient liquid chromatography. Intra-assay imprecision was determined by 11 replicates of samples containing low and high concentration (CV<15%). Carryover was determined by assaying triplicates of cell lysate-free cocktails directly after injection of high enzyme activity sample (less than 0.1%). No matrix effect was found. The GALC enzyme activity was calculated and standardized by corresponding product and internal standard ratios from 5-point standard curve. The range of enzyme activity from three, known affected patients is 0.01–0.07 (nmol/hr/mg protein); whereas, two identified carriers had enzyme activate in the range of 0.14–0.40 (nmol/hr/mg protein). The reference interval was established from 63 residual, unaffected samples and was 0.12–5.97 (1.44±1.44) nmol/hr/mg protein. Conclusions A simple and multiplexed LC-MS/MS assay was developed which can measure small amounts of residual GALC enzyme activity in leukocytes. This confirmatory assay will aid in the diagnosis and prognosis (i.e. differentiate disease severity) of Krabbe disease and other lysosomal storage disorders.

Glycosylation- and phosphorylation-dependent intracellular transport of lysosomal hydrolases

2009 ◽  
Vol 390 (7) ◽  
Author(s):  
Sandra Pohl ◽  
Katrin Marschner ◽  
Stephan Storch ◽  
Thomas Braulke
Keyword(s):  
Lysosomal Enzymes ◽  
Intracellular Transport ◽  
Dependent Manner ◽  
Lysosomal Storage ◽  
Lysosomal Hydrolases ◽  
Structural Requirements ◽  
Preferential Binding ◽  
High Mannose ◽  
Biosynthetic Studies ◽  
Storage Disorders

Abstract Lysosomes contain more than 50 soluble hydrolases that are targeted to lysosomes in a mannose 6-phosphate (Man6P)-dependent manner. The phosphorylation of man- nose residues on high mannose-type oligosaccharides of newly synthesized lysosomal enzymes is catalyzed by two multimeric enzymes, GlcNAc-1-phosphotransferase and GlcNAc-1-phosphodiester-α-N-acetylglucosaminidase, allowing the binding to two distinct Man6P receptors in the Golgi apparatus. Inherited defects in the GlcNAc-1-phosphotransferase complex result in missorting and cellular loss of lysosomal enzymes, and the subsequent lysosomal dysfunction causes the lysosomal storage disorders mucolipidosis types II and III. Biosynthetic studies and the availability of Man6P receptor-deficient mouse models have provided new insights into the structural requirements for preferential binding of subsets of lysosomal enzymes to Man6P receptors as well as the identification of alternative targeting pathways.

scholarly journals The Lysosome: A Potential Therapeutic Juncture between the COVID-19 Pandemic and Niemann-Pick Type C Disease

2020 ◽  
Author(s):  
Rami Ballout
Keyword(s):  
Mechanisms Of Action ◽  
Comparable Efficacy ◽  
Lysosomal Storage ◽  
Viral Propagation ◽  
Lysosomal Dysfunction ◽  
The World ◽  
The Face ◽  
Type C ◽  
Niemann Pick ◽  
Storage Disorders

In the face of the newly emergent COVID-19 pandemic, researchers around the world are racing to identify efficacious drugs capable of preventing or treating its infection. They are doing that by testing already available and approved antimicrobials for their rapid repurposing against COVID-19. Using the data emerging on the comparable efficacy of various compounds having different mechanisms of action and indications, I suggest in this report, their potential mechanistic convergence. Specifically, I highlight the lysosome as a key possible therapeutic target for COVID-19, proposing one of the lysosomal storage disorders, Niemann-Pick type C disease (NPC), as a prototypical condition with inherent resistance or an “unfavorable” host cell environment for viral propagation. The included reasoning evolves from previously generated data in NPC, along with the emerging data on COVID-19. The aim of this report is to suggest that pharmacological induction of a “transient” NPC-like lysosomal dysfunction, could hold answers for targeting the ongoing COVID-19 pandemic.

scholarly journals Tandem Mass Spectrometry Has a Larger Analytical Range than Fluorescence Assays of Lysosomal Enzymes: Application to Newborn Screening and Diagnosis of Mucopolysaccharidoses Types II, IVA, and VI

2015 ◽  
Vol 61 (11) ◽  
pp. 1363-1371 ◽  
Author(s):  
Arun Babu Kumar ◽  
Sophia Masi ◽  
Farideh Ghomashchi ◽  
Naveen Kumar Chennamaneni ◽  
Makoto Ito ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Newborn Screening ◽  
Lysosomal Enzymes ◽  
Lysosomal Storage Diseases ◽  
Tandem Mass ◽  
Lysosomal Storage ◽  
Storage Diseases ◽  
Mps Ii ◽  
Analytical Range ◽  
Screening And Diagnosis

Abstract BACKGROUND There is interest in newborn screening and diagnosis of lysosomal storage diseases because of the development of treatment options that improve clinical outcome. Assays of lysosomal enzymes with high analytical range (ratio of assay response from the enzymatic reaction divided by the assay response due to nonenzymatic processes) are desirable because they are predicted to lead to a lower rate of false positives in population screening and to more accurate diagnoses. METHODS We designed new tandem mass spectrometry (MS/MS) assays that give the largest analytical ranges reported to date for the use of dried blood spots (DBS) for detection of mucopolysaccharidoses type II (MPS-II), MPS-IVA, and MPS-VI. For comparison, we carried out fluorometric assays of 6 lysosomal enzymes using 4-methylumbelliferyl (4MU)-substrate conjugates. RESULTS The MS/MS assays for MPS-II, -IVA, and -VI displayed analytical ranges that are 1–2 orders of magnitude higher than those for the corresponding fluorometric assays. The relatively small analytical ranges of the 4MU assays are due to the intrinsic fluorescence of the 4MU substrates, which cause high background in the assay response. CONCLUSIONS These highly reproducible MS/MS assays for MPS-II, -IVA, and -VI can support multiplex newborn screening of these lysosomal storage diseases. MS/MS assays of lysosomal enzymes outperform 4MU fluorometric assays in terms of analytical range. Ongoing pilot studies will allow us to gauge the impact of the increased analytical range on newborn screening performance.

scholarly journals The Role of Exosomes in Lysosomal Storage Disorders

Biomolecules ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 576
Author(s):  
Adenrele M. Gleason ◽  
Elizabeth G. Woo ◽  
Cindy McKinney ◽  
Ellen Sidransky
Keyword(s):  
Cell Types ◽  
Lysosomal Storage Disorders ◽  
Lysosomal Storage ◽  
Lysosomal Disorders ◽  
Lysosomal Dysfunction ◽  
Endosomal Membranes ◽  
A Cell ◽  
The Central Nervous System ◽  
And Function ◽  
Storage Disorders

Exosomes, small membrane-bound organelles formed from endosomal membranes, represent a heterogenous source of biological and pathological biomarkers capturing the metabolic status of a cell. Exosomal cargo, including lipids, proteins, mRNAs, and miRNAs, can either act as inter-cellular messengers or are shuttled for autophagic/lysosomal degradation. Most cell types in the central nervous system (CNS) release exosomes, which serve as long and short distance communicators between neurons, astrocytes, oligodendrocytes, and microglia. Lysosomal storage disorders are diseases characterized by the accumulation of partially or undigested cellular waste. The exosomal content in these diseases is intrinsic to each individual disorder. Emerging research indicates that lysosomal dysfunction enhances exocytosis, and hence, in lysosomal disorders, exosomal secretion may play a role in disease pathogenesis. Furthermore, the unique properties of exosomes and their ability to carry cargo between adjacent cells and organs, and across the blood–brain barrier, make them attractive candidates for use as therapeutic delivery vehicles. Thus, understanding exosomal content and function may have utility in the treatment of specific lysosomal storage disorders. Since lysosomal dysfunction and the deficiency of at least one lysosomal enzyme, glucocerebrosidase, is associated with the development of parkinsonism, the study and use of exosomes may contribute to an improved understanding of Parkinson disease, potentially leading to new therapeutics.

scholarly journals Lyso-glycosphingolipids: presence and consequences

2020 ◽  
Vol 64 (3) ◽  
pp. 565-578 ◽  
Author(s):  
Marco van Eijk ◽  
Maria J. Ferraz ◽  
Rolf G. Boot ◽  
Johannes M.F.G. Aerts
Keyword(s):  
Metachromatic Leukodystrophy ◽  
Lysosomal Storage Diseases ◽  
Krabbe Disease ◽  
Lysosomal Storage ◽  
Gm2 Gangliosidosis ◽  
Acid Ceramidase ◽  
Lysosomal Diseases ◽  
Type C ◽  
Niemann Pick ◽  
Storage Disorders

Abstract Lyso-glycosphingolipids are generated in excess in glycosphingolipid storage disorders. In the course of these pathologies glycosylated sphingolipid species accumulate within lysosomes due to flaws in the respective lipid degrading machinery. Deacylation of accumulating glycosphingolipids drives the formation of lyso-glycosphingolipids. In lysosomal storage diseases such as Gaucher Disease, Fabry Disease, Krabbe disease, GM1 -and GM2 gangliosidosis, Niemann Pick type C and Metachromatic leukodystrophy massive intra-lysosomal glycosphingolipid accumulation occurs. The lysosomal enzyme acid ceramidase generates the deacylated lyso-glycosphingolipid species. This review discusses how the various lyso-glycosphingolipids are synthesized, how they may contribute to abnormal immunity in glycosphingolipid storing lysosomal diseases and what therapeutic opportunities exist.

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