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Pathobiology : Journal of... 2016We present a brief review of Gaucher disease (GD), the most common lysosomal storage disease. GD is a rare autosomal recessive disorder characterized by the defective... (Review)
Review
We present a brief review of Gaucher disease (GD), the most common lysosomal storage disease. GD is a rare autosomal recessive disorder characterized by the defective function of the catabolic enzyme β-glucocerebrosidase (GBA), leading to an accumulation of its substrate, glucocerebroside. Clinical signs and symptoms include neurological dysfunctions, bone infarcts and malformations, hepatosplenomegaly and hypersplenism leading to anemia, neutropenia and thrombocytopenia. Enzyme replacement therapy with recombinant GBA is the mainstay of treatment for GD, which became the first successfully managed lipid storage disease. Future treatments may include oral enzyme replacement and/or gene therapy interventions.
Topics: Enzyme Replacement Therapy; Gaucher Disease; Genetic Therapy; Glucosylceramidase; Humans; Hypersplenism; Splenomegaly
PubMed: 26588331
DOI: 10.1159/000440865 -
Journal of Parkinson's Disease 2021Human genetic studies as well as studies in animal models indicate that lysosomal dysfunction plays a key role in the pathogenesis of Parkinson's disease. Among the... (Review)
Review
Human genetic studies as well as studies in animal models indicate that lysosomal dysfunction plays a key role in the pathogenesis of Parkinson's disease. Among the lysosomal genes involved, GBA1 has the largest impact on Parkinson's disease risk. Deficiency in the GBA1 encoded enzyme glucocerebrosidase (GCase) leads to the accumulation of the GCase glycolipid substrates glucosylceramide and glucosylsphingosine and ultimately results in toxicity and inflammation and negatively affect many clinical aspects of Parkinson's disease, including disease risk, the severity of presentation, age of onset, and likelihood of progression to dementia. These findings support the view that re-establishing normal levels of GCase enzyme activity may reduce the progression of Parkinson's disease in patients carrying GBA1 mutations. Studies in mouse models indicate that PR001, a AAV9 vector-based gene therapy designed to deliver a functional GBA1 gene to the brain, suggest that this therapeutic approach may slow or stop disease progression. PR001 is currently being evaluated in clinical trials with Parkinson's disease patients carrying GBA1 mutations.
Topics: Animals; Gaucher Disease; Genetic Therapy; Glucosylceramidase; Humans; Lysosomes; Mice; Mutation; Parkinson Disease; alpha-Synuclein
PubMed: 34151863
DOI: 10.3233/JPD-212739 -
TRIP12 ubiquitination of glucocerebrosidase contributes to neurodegeneration in Parkinson's disease.Neuron Dec 2021Impairment in glucocerebrosidase (GCase) is strongly associated with the development of Parkinson's disease (PD), yet the regulators responsible for its impairment...
Impairment in glucocerebrosidase (GCase) is strongly associated with the development of Parkinson's disease (PD), yet the regulators responsible for its impairment remain elusive. In this paper, we identify the E3 ligase Thyroid Hormone Receptor Interacting Protein 12 (TRIP12) as a key regulator of GCase. TRIP12 interacts with and ubiquitinates GCase at lysine 293 to control its degradation via ubiquitin proteasomal degradation. Ubiquitinated GCase by TRIP12 leads to its functional impairment through premature degradation and subsequent accumulation of α-synuclein. TRIP12 overexpression causes mitochondrial dysfunction, which is ameliorated by GCase overexpression. Further, conditional TRIP12 knockout in vitro and knockdown in vivo promotes the expression of GCase, which blocks α-synuclein preformed fibrils (α-syn PFFs)-provoked dopaminergic neurodegeneration. Moreover, TRIP12 accumulates in human PD brain and α-synuclein-based mouse models. The identification of TRIP12 as a regulator of GCase provides a new perspective on the molecular mechanisms underlying dysfunctional GCase-driven neurodegeneration in PD.
Topics: Animals; Brain; Carrier Proteins; Disease Models, Animal; Glucosylceramidase; Mice; Parkinson Disease; Ubiquitin-Protein Ligases; Ubiquitination; alpha-Synuclein
PubMed: 34644545
DOI: 10.1016/j.neuron.2021.09.031 -
Nature Neuroscience Mar 2020Parkinson's disease is a synucleinopathy that is characterized by motor dysfunction, death of midbrain dopaminergic neurons and accumulation of α-synuclein (α-Syn)...
Parkinson's disease is a synucleinopathy that is characterized by motor dysfunction, death of midbrain dopaminergic neurons and accumulation of α-synuclein (α-Syn) aggregates. Evidence suggests that α-Syn aggregation can originate in peripheral tissues and progress to the brain via autonomic fibers. We tested this by inoculating the duodenal wall of mice with α-Syn preformed fibrils. Following inoculation, we observed gastrointestinal deficits and physiological changes to the enteric nervous system. Using the AAV-PHP.S capsid to target the lysosomal enzyme glucocerebrosidase for peripheral gene transfer, we found that α-Syn pathology is reduced due to the increased expression of this protein. Lastly, inoculation of α-Syn fibrils in aged mice, but not younger mice, resulted in progression of α-Syn histopathology to the midbrain and subsequent motor defects. Our results characterize peripheral synucleinopathy in prodromal Parkinson's disease and explore cellular mechanisms for the gut-to-brain progression of α-Syn pathology.
Topics: Animals; Brain; Digestive System Diseases; Duodenum; Enteric Nervous System; Glucosylceramidase; Mesencephalon; Mice; Mice, Inbred C57BL; Movement Disorders; Nerve Fibers; Nociception; Nodose Ganglion; Synucleinopathies
PubMed: 32066981
DOI: 10.1038/s41593-020-0589-7 -
Autophagy Jan 2019Heterozygous mutations in GBA, the gene encoding the lysosomal enzyme glucosylceramidase beta/β-glucocerebrosidase, comprise the most common genetic risk factor for...
Heterozygous mutations in GBA, the gene encoding the lysosomal enzyme glucosylceramidase beta/β-glucocerebrosidase, comprise the most common genetic risk factor for Parkinson disease (PD), but the mechanisms underlying this association remain unclear. Here, we show that in Gba knockin mice, the L444P heterozygous Gba mutation triggers mitochondrial dysfunction by inhibiting autophagy and mitochondrial priming, two steps critical for the selective removal of dysfunctional mitochondria by autophagy, a process known as mitophagy. In SHSY-5Y neuroblastoma cells, the overexpression of L444P GBA impeded mitochondrial priming and autophagy induction when endogenous lysosomal GBA activity remained intact. By contrast, genetic depletion of GBA inhibited lysosomal clearance of autophagic cargo. The link between heterozygous GBA mutations and impaired mitophagy was corroborated in postmortem brain tissue from PD patients carrying heterozygous GBA mutations, where we found increased mitochondrial content, mitochondria oxidative stress and impaired autophagy. Our findings thus suggest a mechanistic basis for mitochondrial dysfunction associated with GBA heterozygous mutations. Abbreviations: AMBRA1: autophagy/beclin 1 regulator 1; BECN1: beclin 1, autophagy related; BNIP3L/Nix: BCL2/adenovirus E1B interacting protein 3-like; CCCP: carbonyl cyanide 3-chloroyphenylhydrazone; CYCS: cytochrome c, somatic; DNM1L/DRP1: dynamin 1-like; ER: endoplasmic reticulum; GBA: glucosylceramidase beta; GBA-PD: Parkinson disease with heterozygous GBA mutations; GD: Gaucher disease; GFP: green fluorescent protein; LC3B: microtubule-associated protein 1 light chain 3 beta; LC3B-II: lipidated form of microtubule-associated protein 1 light chain 3 beta; MitoGreen: MitoTracker Green; MitoRed: MitoTracker Red; MMP: mitochondrial membrane potential; MTOR: mechanistic target of rapamycin kinase; MYC: MYC proto-oncogene, bHLH transcription factor; NBR1: NBR1, autophagy cargo receptor; Non-GBA-PD: Parkinson disease without GBA mutations; PD: Parkinson disease; PINK1: PTEN induced putative kinase 1; PRKN/PARK2: parkin RBR E3 ubiquitin protein ligase; RFP: red fluorescent protein; ROS: reactive oxygen species; SNCA: synuclein alpha; SQSTM1/p62: sequestosome 1; TIMM23: translocase of inner mitochondrial membrane 23; TOMM20: translocase of outer mitochondrial membrane 20; VDAC1/Porin: voltage dependent anion channel 1; WT: wild type.
Topics: Animals; Cell Line, Tumor; Gene Expression; Glucosylceramidase; Gyrus Cinguli; Humans; Lysosomes; Mice; Mice, Knockout; Mitochondria; Mitochondrial Membranes; Mitophagy; Mutation; Parkinson Disease; Proto-Oncogene Mas; Reactive Oxygen Species
PubMed: 30160596
DOI: 10.1080/15548627.2018.1509818 -
Journal of Neural Transmission (Vienna,... Sep 2022The discovery of glucocerebrosidase (GBA1) mutations as the greatest numerical genetic risk factor for the development of Parkinson disease (PD) resulted in a paradigm... (Review)
Review
The discovery of glucocerebrosidase (GBA1) mutations as the greatest numerical genetic risk factor for the development of Parkinson disease (PD) resulted in a paradigm shift within the research landscape. Efforts to elucidate the mechanisms behind GBA1-associated PD have highlighted shared pathways in idiopathic PD including the loss and gain-of-function hypotheses, endoplasmic reticulum stress, lipid metabolism, neuroinflammation, mitochondrial dysfunction and altered autophagy-lysosomal pathway responsible for degradation of aggregated and misfolded a-synuclein. GBA1-associated PD exhibits subtle differences in phenotype and disease progression compared to idiopathic counterparts notably an earlier age of onset, faster motor decline and greater frequency of non-motor symptoms (which also constitute a significant aspect of the prodromal phase of the disease). GBA1-targeted therapies have been developed and are being investigated in clinical trials. The most notable are Ambroxol, a small molecule chaperone, and Venglustat, a blood-brain-barrier-penetrant substrate reduction therapy agent. It is imperative that further studies clarify the aetiology of GBA1-associated PD, enabling the development of a greater abundance of targeted therapies in this new era of precision medicine.
Topics: Glucosylceramidase; Humans; Lysosomes; Mutation; Parkinson Disease; alpha-Synuclein
PubMed: 35932311
DOI: 10.1007/s00702-022-02531-3 -
Science Advances Feb 2022The most common genetic risk factors for Parkinson's disease (PD) are a set of heterozygous mutant (MT) alleles of the gene that encodes β-glucocerebrosidase (GCase),...
The most common genetic risk factors for Parkinson's disease (PD) are a set of heterozygous mutant (MT) alleles of the gene that encodes β-glucocerebrosidase (GCase), an enzyme normally trafficked through the ER/Golgi apparatus to the lysosomal lumen. We found that half of the GCase in lysosomes from postmortem human GBA-PD brains was present on the lysosomal surface and that this mislocalization depends on a pentapeptide motif in GCase used to target cytosolic protein for degradation by chaperone-mediated autophagy (CMA). MT GCase at the lysosomal surface inhibits CMA, causing accumulation of CMA substrates including α-synuclein. Single-cell transcriptional analysis and proteomics of brains from GBA-PD patients confirmed reduced CMA activity and proteome changes comparable to those in CMA-deficient mouse brain. Loss of the MT GCase CMA motif rescued primary substantia nigra dopaminergic neurons from MT GCase-induced neuronal death. We conclude that MT alleles block CMA function and produce α-synuclein accumulation.
Topics: Animals; Chaperone-Mediated Autophagy; Glucosylceramidase; Humans; Mice; Mutation; Parkinson Disease; alpha-Synuclein
PubMed: 35138901
DOI: 10.1126/sciadv.abm6393 -
Cellular and Molecular Neurobiology Aug 2015Gaucher disease is associated with Parkinson's disease (PD) by mutations in glucocerebrosidase (GCase). The gene encoding GCase, glucosidase beta acid (GBA), is an... (Review)
Review
Gaucher disease is associated with Parkinson's disease (PD) by mutations in glucocerebrosidase (GCase). The gene encoding GCase, glucosidase beta acid (GBA), is an important risk factor for PD. Findings from large studies have shown that patients with PD have an increased frequency of mutations in GBA and that GBA mutation carriers exhibit diverse parkinsonian phenotypes and Lewy body pathology. Although the mechanism for this association remains elusive, some hypotheses have been proposed to explain it, including gain of function caused by GBA mutations, which increases α-synuclein (α-syn) aggregation, loss of function due to lysosomal enzyme deficiency, which affects α-syn clearance, and even a bidirectional feedback loop, but each of these hypotheses has its limitations. It is also worth noting that many findings have implicated the interaction between α-syn and GCase, indicating the essential role of the interaction in the pathogenesis of GBA-associated parkinsonism. Therefore, the current review focuses on α-syn and GCase, and it provides some new thoughts that may be helpful for understanding the α-syn-GCase interaction and unraveling the exact mechanism underlying GBA-associated parkinsonism.
Topics: Animals; Epistasis, Genetic; Gaucher Disease; Glucosylceramidase; Heterozygote; Humans; Mutation; Parkinsonian Disorders; alpha-Synuclein
PubMed: 25820783
DOI: 10.1007/s10571-015-0176-8 -
JAMA Neurology Apr 2020Mutations of the glucocerebrosidase gene, GBA1 (OMIM 606463), are the most important risk factor for Parkinson disease (PD). In vitro and in vivo studies have reported... (Clinical Trial)
Clinical Trial
IMPORTANCE
Mutations of the glucocerebrosidase gene, GBA1 (OMIM 606463), are the most important risk factor for Parkinson disease (PD). In vitro and in vivo studies have reported that ambroxol increases β-glucocerebrosidase (GCase) enzyme activity and reduces α-synuclein levels. These observations support a potential role for ambroxol therapy in modifying a relevant pathogenetic pathway in PD.
OBJECTIVE
To assess safety, tolerability, cerebrospinal fluid (CSF) penetration, and target engagement of ambroxol therapy with GCase in patients with PD with and without GBA1 mutations.
INTERVENTIONS
An escalating dose of oral ambroxol to 1.26 g per day.
DESIGN, SETTING, AND PARTICIPANTS
This single-center open-label noncontrolled clinical trial was conducted between January 11, 2017, and April 25, 2018, at the Leonard Wolfson Experimental Neuroscience Centre, a dedicated clinical research facility and part of the University College London Queen Square Institute of Neurology in London, United Kingdom. Participants were recruited from established databases at the Royal Free London Hospital and National Hospital for Neurology and Neurosurgery in London. Twenty-four patients with moderate PD were evaluated for eligibility, and 23 entered the study. Of those, 18 patients completed the study; 1 patient was excluded (failed lumbar puncture), and 4 patients withdrew (predominantly lumbar puncture-related complications). All data analyses were performed from November 1 to December 14, 2018.
MAIN OUTCOMES AND MEASURES
Primary outcomes at 186 days were the detection of ambroxol in the CSF and a change in CSF GCase activity.
RESULTS
Of the 18 participants (15 men [83.3%]; mean [SD] age, 60.2 [9.7] years) who completed the study, 17 (8 with GBA1 mutations and 9 without GBA1 mutations) were included in the primary analysis. Between days 0 and 186, a 156-ng/mL increase in the level of ambroxol in CSF (lower 95% confidence limit, 129 ng/mL; P < .001) was observed. The CSF GCase activity decreased by 19% (0.059 nmol/mL per hour; 95% CI, -0.115 to -0.002; P = .04). The ambroxol therapy was well tolerated, with no serious adverse events. An increase of 50 pg/mL (13%) in the CSF α-synuclein concentration (95% CI, 14-87; P = .01) and an increase of 88 ng/mol (35%) in the CSF GCase protein levels (95% CI, 40-137; P = .002) were observed. Mean (SD) scores on part 3 of the Movement Disorders Society Unified Parkinson Disease Rating Scale decreased (ie, improved) by 6.8 (7.1) points (95% CI, -10.4 to -3.1; P = .001). These changes were observed in patients with and without GBA1 mutations.
CONCLUSIONS AND RELEVANCE
The study results suggest that ambroxol therapy was safe and well tolerated; CSF penetration and target engagement of ambroxol were achieved, and CSF α-synuclein levels were increased. Placebo-controlled clinical trials are needed to examine whether ambroxol therapy is associated with changes in the natural progression of PD.
TRIAL REGISTRATION
ClinicalTrials.gov identifier: NCT02941822; EudraCT identifier: 2015-002571-24.
Topics: Aged; Ambroxol; Glucosylceramidase; Humans; Male; Middle Aged; Mutation; Parkinson Disease; Treatment Outcome
PubMed: 31930374
DOI: 10.1001/jamaneurol.2019.4611 -
Nature Communications Apr 2023Mutations in GBA1, the gene encoding the lysosomal enzyme β-glucocerebrosidase (GCase), which cause Gaucher's disease, are the most frequent genetic risk factor for...
Mutations in GBA1, the gene encoding the lysosomal enzyme β-glucocerebrosidase (GCase), which cause Gaucher's disease, are the most frequent genetic risk factor for Parkinson's disease (PD). Here, we employ global proteomic and single-cell genomic approaches in stable cell lines as well as induced pluripotent stem cell (iPSC)-derived neurons and midbrain organoids to dissect the mechanisms underlying GCase-related neurodegeneration. We demonstrate that GCase can be imported from the cytosol into the mitochondria via recognition of internal mitochondrial targeting sequence-like signals. In mitochondria, GCase promotes the maintenance of mitochondrial complex I (CI) integrity and function. Furthermore, GCase interacts with the mitochondrial quality control proteins HSP60 and LONP1. Disease-associated mutations impair CI stability and function and enhance the interaction with the mitochondrial quality control machinery. These findings reveal a mitochondrial role of GCase and suggest that defective CI activity and energy metabolism may drive the pathogenesis of GCase-linked neurodegeneration.
Topics: Humans; Glucosylceramidase; Proteomics; Parkinson Disease; Mitochondria; Energy Metabolism; Mutation; Lysosomes; alpha-Synuclein; Mitochondrial Proteins; ATP-Dependent Proteases
PubMed: 37024507
DOI: 10.1038/s41467-023-37454-4