scholarly journals Cln6 mutants associated with neuronal ceroid lipofuscinosis are degraded in a proteasome-dependent manner

2009 ◽  
Vol 29 (3) ◽  
pp. 173-181 ◽  
Author(s):  
Kristina Oresic ◽  
Britta Mueller ◽  
Domenico Tortorella
Keyword(s):  
Quality Control ◽  
Protein Extraction ◽  
Neuronal Ceroid Lipofuscinosis ◽  
Point Mutations ◽  
Lysosomal Storage Diseases ◽  
Neuronal Ceroid Lipofuscinoses ◽  
Dependent Manner ◽  
Lysosomal Storage ◽  
Er Quality Control ◽  
Recessive Mutations

NCLs (neuronal ceroid lipofuscinoses), a group of inherited neurodegenerative lysosomal storage diseases that predominantly affect children, are the result of autosomal recessive mutations within one of the nine cln genes. The wild-type cln gene products are composed of membrane and soluble proteins that localize to the lysosome or the ER (endoplasmic reticulum). However, the destiny of the Cln variants has not been fully characterized. To explore a possible link between ER quality control and processing of Cln mutants, we investigated the fate of two NCL-related Cln6 mutants found in patient samples (Cln6G123D and Cln6M241T) in neuronal-derived human cells. The point mutations are predicted to be in the putative transmembrane domains and most probably generate misfolded membrane proteins that are subjected to ER quality control. Consistent with this paradigm, both mutants underwent rapid proteasome-mediated degradation and complexed with components of the ER extraction apparatus, Derlin-1 and p97. In addition, knockdown of SEL1L [sel-1 suppressor of lin-12-like (Caenorhabditis elegans)], a member of an E3 ubiquitin ligase complex involved in ER protein extraction, rescued significant amounts of Cln6G123D and Cln6M241T polypeptides. The results implicate ER quality control in the instability of the Cln variants that probably contributes to the development of NCL.

scholarly journals Exposure of bipartite hydrophobic signal triggers nuclear quality control of Ndc10 at the endoplasmic reticulum/nuclear envelope

2011 ◽  
Vol 22 (24) ◽  
pp. 4726-4739 ◽  
Author(s):  
Noa Furth ◽  
Or Gertman ◽  
Ayala Shiber ◽  
Omri S. Alfassy ◽  
Itamar Cohen ◽  
...  
Keyword(s):  
Quality Control ◽  
Endoplasmic Reticulum ◽  
Protein Folding ◽  
Nuclear Envelope ◽  
Reverse Genetics ◽  
Point Mutations ◽  
Hydrophobic Surface ◽  
Structural Features ◽  
Er Quality Control ◽  
C Terminus

Proper functioning of the protein-folding quality control network depends on the network's ability to discern diverse structural perturbations to the native states of its protein substrates. Despite the centrality of the detection of misfolded states to cell home­ostasis, very little is known about the exact sequence and structural features that mark a protein as being misfolded. To investigate these features, we studied the requirements for the degradation of the yeast kinetochore protein Ndc10p. Mutant Ndc10p is a substrate of a protein-folding quality control pathway mediated by the E3 ubiquitin (Ub) ligase Doa10p at the endoplasmic reticulum (ER)/nuclear envelope membrane. Analysis of Ndc10p mutant derivatives, employing a reverse genetics approach, identified an autonomous quality control–associated degradation motif near the C-terminus of the protein. This motif is composed of two indispensable hydrophobic elements: a hydrophobic surface of an amphipathic helix and a loosely structured hydrophobic C-terminal tail. Site-specific point mutations expose these elements, triggering ubiquitin-mediated and HSP70 chaperone–dependent degradation of Ndc10p. These findings substantiate the ability of the ER quality control system to recognize subtle perturbation(s) in the native structure of a nuclear protein.

scholarly journals A Drosophila model of neuronal ceroid lipofuscinosis CLN4 reveals a hypermorphic gain of function mechanism

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Elliot Imler ◽  
Jin Sang Pyon ◽  
Selina Kindelay ◽  
Meaghan Torvund ◽  
Yong-quan Zhang ◽  
...  
Keyword(s):  
Membrane Trafficking ◽  
Neuronal Ceroid Lipofuscinosis ◽  
Gene Dosage ◽  
Neuronal Ceroid Lipofuscinoses ◽  
Dependent Manner ◽  
Membrane Structures ◽  
Gain Of Function ◽  
Function Mechanism ◽  
Ubiquitinated Proteins ◽  
Drosophila Model

The autosomal dominant neuronal ceroid lipofuscinoses (NCL) CLN4 is caused by mutations in the synaptic vesicle (SV) protein CSPα. We developed animal models of CLN4 by expressing CLN4 mutant human CSPα (hCSPα) in Drosophila neurons. Similar to patients, CLN4 mutations induced excessive oligomerization of hCSPα and premature lethality in a dose-dependent manner. Instead of being localized to SVs, most CLN4 mutant hCSPα accumulated abnormally, and co-localized with ubiquitinated proteins and the prelysosomal markers HRS and LAMP1. Ultrastructural examination revealed frequent abnormal membrane structures in axons and neuronal somata. The lethality, oligomerization and prelysosomal accumulation induced by CLN4 mutations was attenuated by reducing endogenous wild type (WT) dCSP levels and enhanced by increasing WT levels. Furthermore, reducing the gene dosage of Hsc70 also attenuated CLN4 phenotypes. Taken together, we suggest that CLN4 alleles resemble dominant hypermorphic gain of function mutations that drive excessive oligomerization and impair membrane trafficking.

VALPROIC ACID EXTENDS LIFESPAN OF THE ZEBRAFISH MODEL OF CLN2 DISEASE (LATE INFANTILE NEURONAL CEROID LIPOFUSCINOSIS)

2015 ◽  
Vol 86 (11) ◽  
pp. e4.153-e4
Author(s):  
Fahad Mahmood ◽  
Anselm Zdebik ◽  
Alexandra Au ◽  
Jennifer Cooke ◽  
Claire Russell
Keyword(s):  
Seizure Activity ◽  
Neuronal Ceroid Lipofuscinosis ◽  
Epileptiform Activity ◽  
Intractable Epilepsy ◽  
Premature Death ◽  
Neuronal Ceroid Lipofuscinoses ◽  
Lysosomal Storage ◽  
Zebrafish Model ◽  
Lysosomal Protease

CLN2 disease is a subtype of the neuronal ceroid lipofuscinoses (NCLs), a group of lysosomal storage disorders causing progressive, untreatable, neurodegeneration, intractable epilepsy and premature death in children. We have developed a permanent genetic zebrafish model of CLN2 disease due to a mutation in tpp1 encoding the lysosomal protease Tripeptidyl-peptidase-1 that replicates the neurodegenerative and storage phenotype. We hypothesize that CLN2 zebrafish display electrical and behavioural evidence of seizure activity that responds to established anti-convulsants and can further be used to develop novel therapeutic approaches.To validate the presence of seizures we performed single electrode electroencephalography showing CLN2 zebrafish had increased spiking activity vs wildtype with Fast-Fourier transform showing significantly increased amplitude about 2–4Hz. This was attenuated by Valproate (p=0.049), but not pentobarbitone. We also demonstrate that Valproate significantly reduces seizure-related movement bouts, thereby correlating movements and epileptiform activity. Lastly, we show exposure to Valproate significantly extends the lifespan of our zebrafish model with mortality between 3–6 days post-fertilization 8.33% in treated vs 33.3% in controls (p=0.01).The CLN2 zebrafish model thus displays electrical and behavioural seizure activity that can be attenuated by Valproate, with associated prolongation in survival. Moreover this model can utilize high-throughput in vivo screening assays to develop novel anti-convulsants.

scholarly journals Large animal models contribute to the development of therapies for central and peripheral nervous system dysfunction in patients with lysosomal storage diseases

2019 ◽  
Vol 28 (R1) ◽  
pp. R119-R131 ◽  
Author(s):  
Brittney L Gurda ◽  
Charles H Vite
Keyword(s):  
Nervous System ◽  
Animal Models ◽  
Peripheral Nervous System ◽  
Neuronal Ceroid Lipofuscinosis ◽  
Lysosomal Storage Diseases ◽  
Large Animal ◽  
Lysosomal Storage ◽  
Storage Diseases ◽  
Large Animal Models ◽  
Biomedical Field

Abstract Lysosomal storage diseases (LSDs) are a group of 70 monogenic disorders characterized by the lysosomal accumulation of a substrate. As a group, LSDs affect ~1 in 5000 live births; however, each individual storage disease is rare, limiting the ability to perform natural history studies or to perform clinical trials. Perhaps in no other biomedical field have naturally occurring large animal (canine, feline, ovine, caprine, and bovine) models been so essential for understanding the fundamentals of disease pathogenesis and for developing safe and effective therapies. These models were critical for the development of hematopoietic stem cell transplantation in α- and β- mannosidosis, fucosidosis, and the mucopolysaccharidoses; enzyme replacement therapy for fucosidosis, the mucopolysaccharidoses, and neuronal ceroid lipofuscinosis; and small molecule therapy in Niemann–Pick type C disease. However, their most notable contributions to the biomedical field are in the development of gene therapy for LSDs. Adeno-associated viral vectors to treat nervous system disease have been evaluated in the large animal models of α-mannosidosis, globoid cell leukodystrophy, GM1 and GM2 gangliosidosis, the mucopolysaccharidoses, and neuronal ceroid lipofuscinosis. This review article will summarize the large animal models available for study as well as their contributions to the development of central and peripheral nervous system dysfunction in LSDs.

scholarly journals Aggregation chimeras provide evidence of in vivo intercellular correction in ovine CLN6 neuronal ceroid lipofuscinosis (Batten disease)

2021 ◽  
Author(s):  
Lucy A. Barry ◽  
Graham W. Kay ◽  
Nadia L. Mitchell ◽  
Samantha J. Murray ◽  
Nigel P. Jay ◽  
...  
Keyword(s):  
Vision Loss ◽  
Inflammatory Responses ◽  
Neuronal Ceroid Lipofuscinosis ◽  
Batten Disease ◽  
Brain Regions ◽  
Glial Activation ◽  
Neuronal Ceroid Lipofuscinoses ◽  
Lysosomal Storage ◽  
Storage Body

AbstractThe neuronal ceroid lipofuscinoses (NCLs; Batten disease) are fatal, mainly childhood, inherited neurodegenerative lysosomal storage diseases. Sheep affected with a CLN6 form display progressive regionally defined glial activation and subsequent neurodegeneration, indicating that neuroinflammation may be causative of pathogenesis. In this study, aggregation chimeras were generated from homozygous unaffected normal and CLN6 affected sheep embryos, resulting in seven chimeric animals with varied proportions of normal to affected cells. These sheep were classified as affected-like, recovering-like or normal-like, based on their cell-genotype ratios and their clinical and neuropathological profiles.Neuropathological examination of the affected-like animals revealed intense glial activation, prominent storage body accumulation and severe neurodegeneration within all cortical brain regions, along with vision loss and decreasing intracranial volumes and cortical thicknesses consistent with ovine CLN6 disease. In contrast, intercellular communication affecting pathology was evident at both the gross and histological level in the normal-like and recovering-like chimeras, resulting in a lack of glial activation and rare storage body accumulation in only a few cells. Initial intracranial volumes of the recovering-like chimeras were below normal but progressively recovered to about normal by two years of age. All had normal cortical thicknesses, and none went blind. Extended neurogenesis was evident in the brains of all the chimeras.This study indicates that although CLN6 is a membrane bound protein, the consequent defect is not cell intrinsic. The lack of glial activation and inflammatory responses in the normal-like and recovering-like chimeras indicate that newly generated cells are borne into a microenvironment conducive to maturation and survival.

EM as an important diagnostic tool in neuronal ceroid-lipofuscinosis (NCL, Batten's disease)

1992 ◽  
Vol 50 (1) ◽  
pp. 628-629
Author(s):  
Wolfgang H. Muss ◽  
Rudolf Puttinger ◽  
Josef Thurner
Keyword(s):  
Neuronal Ceroid Lipofuscinosis ◽  
Autosomal Recessive Inheritance ◽  
Neuronal Ceroid Lipofuscinoses ◽  
Lysosomal Storage ◽  
Mitochondrial Atp Synthase ◽  
Important Diagnostic Tool ◽  
Storage Products ◽  
Batten's Disease ◽  
Nerve System ◽  
Ceroid Lipofuscin

Neuronal Ceroid-Lipofuscinoses (NCL) are a group of neurometabolic/neurodegenerative disorders characterized by an accumulation of metabolites (autofluorescent “1ipopigments-Ceroid-Lipofuscin”) in central and peripheral nerve system as well as in retina, skeletal muscle, fibroblasts, histiocytes and other body organs. Batten's Disease (syn:SPIELMEYER-VOGT Disease; iuvenile onset NCL) presents with an autosomal recessive inheritance (1). Immunochemical studies (2) suggest that subunit c of mitochondrial ATP-Synthase is stored in the late infantile, iuvenile and adult forms of NCL ; chromosome studies indicate Batten's Disease maps to human chromosome 16 (3); erythrocyte and platelet phospholipids and fatty acids have been reported to be decreased (4), also concentrations of phosphorylated dolichol are reported to be 10 to 20-fold higher in brain from NCL than age-matched controls (5). Intracel1ular/lysosomal storage products histologically are PAS-positive, extractable and, ultrastructurally, the inclusions/accumulation products display characteristic recti-and curvilinear profiles as well as fingerprint bodies (for histological / ultrastructural classification criteria cf. (6)).

scholarly journals Arabidopsis ROCK1 transports UDP-GlcNAc/UDP-GalNAc and regulates ER protein quality control and cytokinin activity

2014 ◽  
Vol 112 (1) ◽  
pp. 291-296 ◽  
Author(s):  
Michael C. E. Niemann ◽  
Isabel Bartrina ◽  
Angel Ashikov ◽  
Henriette Weber ◽  
Ondřej Novák ◽  
...  
Keyword(s):  
Quality Control ◽  
Secretory Pathway ◽  
Protein Quality ◽  
Formation Rate ◽  
Cytokinin Activity ◽  
Dependent Manner ◽  
Er Quality Control ◽  
Sugar Transporters ◽  
Unfolded Protein ◽  
Nucleotide Sugars

The formation of glycoconjugates depends on nucleotide sugars, which serve as donor substrates for glycosyltransferases in the lumen of Golgi vesicles and the endoplasmic reticulum (ER). Import of nucleotide sugars from the cytosol is an important prerequisite for these reactions and is mediated by nucleotide sugar transporters. Here, we report the identification of REPRESSOR OF CYTOKININ DEFICIENCY 1 (ROCK1, At5g65000) as an ER-localized facilitator of UDP-N-acetylglucosamine (UDP-GlcNAc) and UDP-N-acetylgalactosamine (UDP-GalNAc) transport in Arabidopsis thaliana. Mutant alleles of ROCK1 suppress phenotypes inferred by a reduced concentration of the plant hormone cytokinin. This suppression is caused by the loss of activity of cytokinin-degrading enzymes, cytokinin oxidases/dehydrogenases (CKXs). Cytokinin plays an essential role in regulating shoot apical meristem (SAM) activity and shoot architecture. We show that rock1 enhances SAM activity and organ formation rate, demonstrating an important role of ROCK1 in regulating the cytokinin signal in the meristematic cells through modulating activity of CKX proteins. Intriguingly, genetic and molecular analysis indicated that N-glycosylation of CKX1 was not affected by the lack of ROCK1-mediated supply of UDP-GlcNAc. In contrast, we show that CKX1 stability is regulated in a proteasome-dependent manner and that ROCK1 regulates the CKX1 level. The increased unfolded protein response in rock1 plants and suppression of phenotypes caused by the defective brassinosteroid receptor bri1-9 strongly suggest that the ROCK1 activity is an important part of the ER quality control system, which determines the fate of aberrant proteins in the secretory pathway.

scholarly journals Tay–Sachs disease mutations in HEXA target the α chain of hexosaminidase A to endoplasmic reticulum–associated degradation

2016 ◽  
Vol 27 (24) ◽  
pp. 3813-3827 ◽  
Author(s):  
Devin Dersh ◽  
Yuichiro Iwamoto ◽  
Yair Argon
Keyword(s):  
Quality Control ◽  
Endoplasmic Reticulum ◽  
Control Mechanisms ◽  
Permissive Temperature ◽  
Lysosomal Storage ◽  
Loss Of Function ◽  
Er Quality Control ◽  
Tay Sachs Disease ◽  
Hexosaminidase A ◽  
Α Chain

Loss of function of the enzyme β-hexosaminidase A (HexA) causes the lysosomal storage disorder Tay–Sachs disease (TSD). It has been proposed that mutations in the α chain of HexA can impair folding, enzyme assembly, and/or trafficking, yet there is surprisingly little known about the mechanisms of these potential routes of pathogenesis. We therefore investigated the biosynthesis and trafficking of TSD-associated HexA α mutants, seeking to identify relevant cellular quality control mechanisms. The α mutants E482K and G269S are defective in enzymatic activity, unprocessed by lysosomal proteases, and exhibit altered folding pathways compared with wild-type α. E482K is more severely misfolded than G269S, as observed by its aggregation and inability to associate with the HexA β chain. Importantly, both mutants are retrotranslocated from the endoplasmic reticulum (ER) to the cytosol and are degraded by the proteasome, indicating that they are cleared via ER-associated degradation (ERAD). Leveraging these discoveries, we observed that manipulating the cellular folding environment or ERAD pathways can alter the kinetics of mutant α degradation. Additionally, growth of patient fibroblasts at a permissive temperature or with chemical chaperones increases cellular Hex activity by improving mutant α folding. Therefore modulation of the ER quality control systems may be a potential therapeutic route for improving some forms of TSD.

scholarly journals Lysosomal Dysfunction Results in Altered Energy Balance

2007 ◽  
Vol 282 (49) ◽  
pp. 35765-35771 ◽  
Author(s):  
Josh C. Woloszynek ◽  
Trey Coleman ◽  
Clay F. Semenkovich ◽  
Mark S. Sands
Keyword(s):  
Neuronal Ceroid Lipofuscinosis ◽  
Caloric Intake ◽  
Lysosomal Storage Diseases ◽  
Lipid Absorption ◽  
Unknown Etiology ◽  
Caloric Content ◽  
Lysosomal Storage ◽  
Enzyme Replacement ◽  
Caloric Density ◽  
Niemann Pick

The mucopolysaccharidosis (MPS) type VII mouse was originally described as the adipose storage deficiency mouse because of its extreme lean phenotype of unknown etiology. Here, we show that adipose storage deficiency and lower leptin levels are common to five different lysosomal storage diseases (LSDs): MPSI, MPSIIIB, MPSVII, Niemann-Pick type A/B, and infantile neuronal ceroid lipofuscinosis. Elevated circulating pro-inflammatory proteins (VCAM1 and MCP1) were found in multiple LSDs. Multiple anti-inflammatory strategies (dexamethasone, MCP1 deficiency, M3 expression) failed to alter adiposity in LSD animals. All of the models had normal or greater caloric intake and lower to normal metabolic rate, fasting plasma glucose, non-esterified fatty acids, cholesterol, and triglycerides. Triglycerides were lower in the livers of MPSI mice, and the trend was lower in the muscle. Lipid absorption and processing in MPSI mice were indistinguishable from those in normal mice following oral gavage of olive oil. The increased lean mass of MPSI and MPSIIIB mice suggests a shift in adipose triglycerides to lysosomal storage. In agreement, MPSI livers had a similar total caloric content but reduced caloric density, indicating a shift in energy from lipids to proteins/carbohydrates (lysosomal storage). Enzyme replacement therapy normalized the caloric density within 48 h without reducing total caloric content. This was due to an increase in lipids. Recycling of stored material is likely reduced or nonexistent. Therefore, to maintain homeostasis, energy is likely diverted to synthesis at the expense of typical energy storage depots. Thus, these diseases will serve as important tools in studying the role of lysosome function in metabolism and obesity.

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