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Mubariz F, Saadin A, Lingenfelter N, Sarkar C, Banerjee A, Lipinski MM, Awad O. Deregulation of mTORC1-TFEB axis in human iPSC model of GBA1-associated Parkinson's disease. Front Neurosci 2023; 17:1152503. [PMID: 37332877 PMCID: PMC10272450 DOI: 10.3389/fnins.2023.1152503] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 05/02/2023] [Indexed: 06/20/2023] Open
Abstract
Mutations in the GBA1 gene are the single most frequent genetic risk factor for Parkinson's disease (PD). Neurodegenerative changes in GBA1-associated PD have been linked to the defective lysosomal clearance of autophagic substrates and aggregate-prone proteins. To elucidate novel mechanisms contributing to proteinopathy in PD, we investigated the effect of GBA1 mutations on the transcription factor EB (TFEB), the master regulator of the autophagy-lysosomal pathway (ALP). Using PD patients' induced-pluripotent stem cells (iPSCs), we examined TFEB activity and regulation of the ALP in dopaminergic neuronal cultures generated from iPSC lines harboring heterozygous GBA1 mutations and the CRISPR/Cas9-corrected isogenic controls. Our data showed a significant decrease in TFEB transcriptional activity and attenuated expression of many genes in the CLEAR network in GBA1 mutant neurons, but not in the isogenic gene-corrected cells. In PD neurons, we also detected increased activity of the mammalian target of rapamycin complex1 (mTORC1), the main upstream negative regulator of TFEB. Increased mTORC1 activity resulted in excess TFEB phosphorylation and decreased nuclear translocation. Pharmacological mTOR inhibition restored TFEB activity, decreased ER stress and reduced α-synuclein accumulation, indicating improvement of neuronal protiostasis. Moreover, treatment with the lipid substrate reducing compound Genz-123346, decreased mTORC1 activity and increased TFEB expression in the mutant neurons, suggesting that mTORC1-TFEB alterations are linked to the lipid substrate accumulation. Our study unveils a new mechanism contributing to PD susceptibility by GBA1 mutations in which deregulation of the mTORC1-TFEB axis mediates ALP dysfunction and subsequent proteinopathy. It also indicates that pharmacological restoration of TFEB activity could be a promising therapeutic approach in GBA1-associated neurodegeneration.
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Affiliation(s)
- Fahad Mubariz
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Afsoon Saadin
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Nicholas Lingenfelter
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Chinmoy Sarkar
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Aditi Banerjee
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Marta M. Lipinski
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Ola Awad
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, United States
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Granek Z, Barczuk J, Siwecka N, Rozpędek-Kamińska W, Kucharska E, Majsterek I. GBA1 Gene Mutations in α-Synucleinopathies-Molecular Mechanisms Underlying Pathology and Their Clinical Significance. Int J Mol Sci 2023; 24. [PMID: 36768367 DOI: 10.3390/ijms24032044] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/17/2023] [Accepted: 01/18/2023] [Indexed: 01/22/2023] Open
Abstract
α-Synucleinopathies comprise a group of neurodegenerative diseases characterized by altered accumulation of a protein called α-synuclein inside neurons and glial cells. This aggregation leads to the formation of intraneuronal inclusions, Lewy bodies, that constitute the hallmark of α-synuclein pathology. The most prevalent α-synucleinopathies are Parkinson's disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA). To date, only symptomatic treatment is available for these disorders, hence new approaches to their therapy are needed. It has been observed that GBA1 mutations are one of the most impactful risk factors for developing α-synucleinopathies such as PD and DLB. Mutations in the GBA1 gene, which encodes a lysosomal hydrolase β-glucocerebrosidase (GCase), cause a reduction in GCase activity and impaired α-synuclein metabolism. The most abundant GBA1 gene mutations are N370S or N409S, L444P/L483P and E326K/E365K. The mechanisms by which GCase impacts α-synuclein aggregation are poorly understood and need to be further investigated. Here, we discuss some of the potential interactions between α-synuclein and GCase and show how GBA1 mutations may impact the course of the most prevalent α-synucleinopathies.
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Brown RA, Voit A, Srikanth MP, Thayer JA, Kingsbury TJ, Jacobson MA, Lipinski MM, Feldman RA, Awad O. mTOR hyperactivity mediates lysosomal dysfunction in Gaucher's disease iPSC-neuronal cells. Dis Model Mech 2019; 12:dmm038596. [PMID: 31519738 PMCID: PMC6826018 DOI: 10.1242/dmm.038596] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 09/06/2019] [Indexed: 12/20/2022] Open
Abstract
Bi-allelic GBA1 mutations cause Gaucher's disease (GD), the most common lysosomal storage disorder. Neuronopathic manifestations in GD include neurodegeneration, which can be severe and rapidly progressive. GBA1 mutations are also the most frequent genetic risk factors for Parkinson's disease. Dysfunction of the autophagy-lysosomal pathway represents a key pathogenic event in GBA1-associated neurodegeneration. Using an induced pluripotent stem cell (iPSC) model of GD, we previously demonstrated that lysosomal alterations in GD neurons are linked to dysfunction of the transcription factor EB (TFEB). TFEB controls the coordinated expression of autophagy and lysosomal genes and is negatively regulated by the mammalian target of rapamycin complex 1 (mTORC1). To further investigate the mechanism of autophagy-lysosomal pathway dysfunction in neuronopathic GD, we examined mTORC1 kinase activity in GD iPSC neuronal progenitors and differentiated neurons. We found that mTORC1 is hyperactive in GD cells as evidenced by increased phosphorylation of its downstream protein substrates. We also found that pharmacological inhibition of glucosylceramide synthase enzyme reversed mTORC1 hyperactivation, suggesting that increased mTORC1 activity is mediated by the abnormal accumulation of glycosphingolipids in the mutant cells. Treatment with the mTOR inhibitor Torin1 upregulated lysosomal biogenesis and enhanced autophagic clearance in GD neurons, confirming that lysosomal dysfunction is mediated by mTOR hyperactivation. Further analysis demonstrated that increased TFEB phosphorylation by mTORC1 results in decreased TFEB stability in GD cells. Our study uncovers a new mechanism contributing to autophagy-lysosomal pathway dysfunction in GD, and identifies the mTOR complex as a potential therapeutic target for treatment of GBA1-associated neurodegeneration.
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Affiliation(s)
- Robert A Brown
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Antanina Voit
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Manasa P Srikanth
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Julia A Thayer
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Tami J Kingsbury
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- University of Maryland Center for Stem Cell Biology and Regenerative Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Marlene A Jacobson
- Moulder Center for Drug Discovery Research, Temple University School of Pharmacy, Philadelphia, PA 19140, USA
| | - Marta M Lipinski
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Ricardo A Feldman
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Ola Awad
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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Chiong MAD, Racoma MJC, Abacan MAR. Genetic and clinical characteristics of Filipino patients with Gaucher disease. Mol Genet Metab Rep 2018; 15:110-115. [PMID: 30023299 PMCID: PMC6047105 DOI: 10.1016/j.ymgmr.2018.03.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 03/23/2018] [Accepted: 03/23/2018] [Indexed: 12/20/2022] Open
Abstract
Gaucher disease (GD) is a lysosomal storage disorder caused by the deficiency of the β-glucocerebrosidase enzyme due to disease causing mutations in the GBA1 (glucosidase beta acid) gene, leading to the abnormal accumulation of the lipid glucocerebroside in lysosomal macrophages. This is a review of the clinical features and molecular profiles of 14 Filipino patients with GD. Five patients presented with type 1 disease, two had type 2 GD and seven had type 3 GD. The age of onset for all types was between 1 and 2 years of age but there was a delay of 2.2 years from the time of symptom onset to confirmation of diagnosis. Hepatosplenomegaly, anemia and thrombocytopenia were present in most of the patients. Stunting was seen in 64.3% and bone abnormalities were present in 63.6%. The most common mutant allele detected in this cohort was L483P (previously L444P), followed by F252I, P358A and G241R. IVS2+1 G>A, N409S and G416S mutations were reported singularly. There were 3 patients who were found to have N131S mutations and one patient with D257V mutation, mutant alleles that have only been reported among the Filipinos to date. Except for N409S, the mutations found in this cohort were generally severe and were congruent with the severe phenotypes found in most patients. Of the 14 patients, only 6 were able to undergo enzyme replacement therapy which significantly improved the hematologic parameters and decreased the sizes of the liver and spleen but did not consistently improve the growth and skeletal abnormalities nor alleviate the neurological manifestations of our patients with GD. Improved monitoring through recommended modalities for assessments and tools for evaluation should be implemented in order to fully appreciate the severity of the disease and accuracy of the response to treatment.
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Affiliation(s)
- Mary Anne D. Chiong
- Institute of Human Genetics, National Institutes of Health University of the Philippines Manila, Philippines
- Department of Pediatrics, Philippine General Hospital, Manila, Philippines
- University of Santo Tomas, Manila, Philippines
| | - Marie Julianne C. Racoma
- Newborn Screening Reference Center, National Institutes of Health, University of the Philippines, Manila, Philippines
| | - Mary Ann R. Abacan
- Institute of Human Genetics, National Institutes of Health University of the Philippines Manila, Philippines
- Department of Pediatrics, Philippine General Hospital, Manila, Philippines
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Affiliation(s)
- Grisel Lopez
- Section of Molecular Neurogenetics, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Gianina Monestime
- Section of Molecular Neurogenetics, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ellen Sidransky
- Section of Molecular Neurogenetics, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
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