Characterization of the ERAD process of the L444P mutant glucocerebrosidase variant

Bendikov-Bar, Inna; Ron, Idit; Filocamo, Mirella; Horowitz, Mia

doi:10.1016/j.bcmd.2010.10.012

Cited by 101 publications

(94 citation statements)

References 33 publications

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“…While our data support recent studies in which homozygous GBA mutations alter lysosomal and mitochondrial function via a loss-of-function mechanisms [10,11,38,39], the specific effects of mutant GBA on mitochondrial priming and autophagy induction indicate a gain-of-toxic-function of the mutant protein. This effect may be attributed to the ER retention of mutant GBA protein, resulting in an unfolded protein response [67,68]. For example, N370S and L444P GBA mutant proteins, but not WT GBA, interact with PRKN/PARK2 within the ER [69], preventing the binding of PRKN/PARK2 to other substrates [70].…”

Section: Discussionmentioning

confidence: 99%

Mitochondrial dysfunction and mitophagy defect triggered by heterozygous GBA mutations

et al. 2018

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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 GbaL444P/WT 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

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Section: Discussionmentioning

confidence: 99%

Mitochondrial dysfunction and mitophagy defect triggered by heterozygous GBA mutations

et al. 2018

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“…To this end, small molecular chaperones designed to cross the blood–brain barrier that are capable of increasing GCase activity are being investigated as a novel therapy for PD to decrease α‐synuclein levels 17, 18, 19, 20, 21, 22, 23, 24, 25…”

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confidence: 99%

Ambroxol effects in glucocerebrosidase and α‐synuclein transgenic mice

Migdalska‐Richards

Daly

Bézard

et al. 2016

Annals of Neurology

159

138

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ObjectiveGaucher disease is caused by mutations in the glucocerebrosidase 1 gene that result in deficiency of the lysosomal enzyme glucocerebrosidase. Both homozygous and heterozygous glucocerebrosidase 1 mutations confer an increased risk for developing Parkinson disease. Current estimates indicate that 10 to 25% of Parkinson patients carry glucocerebrosidase 1 mutations. Ambroxol is a small molecule chaperone that has been shown to increase glucocerebrosidase activity in vitro. This study investigated the effect of ambroxol treatment on glucocerebrosidase activity and on α‐synuclein and phosphorylated α‐synuclein protein levels in mice.MethodsMice were treated with ambroxol for 12 days. After the treatment, glucocerebrosidase activity was measured in the mouse brain lysates. The brain lysates were also analyzed for α‐synuclein and phosphorylated α‐synuclein protein levels.ResultsAmbroxol treatment resulted in increased brain glucocerebrosidase activity in (1) wild‐type mice, (2) transgenic mice expressing the heterozygous L444P mutation in the murine glucocerebrosidase 1 gene, and (3) transgenic mice overexpressing human α‐synuclein. Furthermore, in the mice overexpressing human α‐synuclein, ambroxol treatment decreased both α‐synuclein and phosphorylated α‐synuclein protein levels.InterpretationOur work supports the proposition that ambroxol should be further investigated as a potential novel disease‐modifying therapy for treatment of Parkinson disease and neuronopathic Gaucher disease to increase glucocerebrosidase activity and decrease α‐synuclein and phosphorylated α‐synuclein protein levels. Ann Neurol 2016;80:766–775

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“…Abnormally folded GCase has been found to accumulate in the ER which results in reduced levels of GCase in the lysosome as well as triggers the unfolded protein response and ER-associated degradation (ERAD) [43][44][45]. Markers of ERAD were indeed found to be increased in the PD-GBA brains (Gegg Ann Neurol 2012).…”

Section: Gcase Leading To Er Stressmentioning

confidence: 99%

Glucocerebrosidase Mutations in Parkinson Disease

O’Regan

deSouza

Balestrino

et al. 2017

JPD

105

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Abstract.Following the discovery of a higher than expected incidence of Parkinson Disease (PD) in Gaucher disease, a lysosomal storage disorder, mutations in the glucocerebrocidase (GBA) gene, which encodes a lysosomal enzyme involved in sphingolipid degradation were explored in the context of idiopathic PD. GBA mutations are now known to be the single largest risk factor for development of idiopathic PD. Clinically, on imaging and pharmacologically, GBA PD is almost identical to idiopathic PD, other than certain features that can be identified in the specialist research setting but not in routine clinical practice. In patients with a known GBA mutation, it is possible to monitor for prodromal signs of PD. The clinical similarity with idiopathic PD and the chance to identify PD at a pre-clinical stage provides a unique opportunity to research therapeutic options for early PD, before major irreversible neurodegeneration occurs. However, to date, the molecular mechanisms which lead to this increased PD risk in GBA mutation carriers are not fully elucidated. Experimental models to define the molecular mechanisms and test therapeutic options include cell culture, transgenic mice and other in vivo models amenable to genetic manipulation, such as drosophilia. Some key pathological pathways of interest in the context of GBA mutations include alpha synuclein aggregation, lysosomal-autophagy axis changes and endoplasmic reticulum stress. Therapeutic agents that exploit these pathways are being developed and include the small molecule chaperone Ambroxol. This review aims to summarise the main features of GBA-PD and provide insights into the pathological relevance of GBA mutations on molecular pathways and the therapeutic implications for PD resulting from investigation of the role of GBA in PD.

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Characterization of the ERAD process of the L444P mutant glucocerebrosidase variant

Cited by 101 publications

References 33 publications

Mitochondrial dysfunction and mitophagy defect triggered by heterozygous GBA mutations

Mitochondrial dysfunction and mitophagy defect triggered by heterozygous GBA mutations

Ambroxol effects in glucocerebrosidase and α‐synuclein transgenic mice

Glucocerebrosidase Mutations in Parkinson Disease

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