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Holling T, Bhavani GS, von Elsner L, Shah H, Kausthubham N, Bhattacharyya SS, Shukla A, Mortier GR, Schinke T, Danyukova T, Pohl S, Kutsche K, Girisha KM. A homozygous hypomorphic BNIP1 variant causes an increase in autophagosomes and reduced autophagic flux and results in a spondylo-epiphyseal dysplasia. Hum Mutat 2022; 43:625-642. [PMID: 35266227 DOI: 10.1002/humu.24368] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 02/24/2022] [Accepted: 03/04/2022] [Indexed: 01/18/2023]
Abstract
BNIP1 (BCL2 interacting protein 1) is a soluble N-ethylmaleimide-sensitive factor-attachment protein receptor involved in ER membrane fusion. We identified the homozygous BNIP1 intronic variant c.84+3A>T in the apparently unrelated patients 1 and 2 with disproportionate short stature. Radiographs showed abnormalities affecting both the axial and appendicular skeleton and spondylo-epiphyseal dysplasia. We detected ~80% aberrantly spliced BNIP1 pre-mRNAs, reduced BNIP1 mRNA level to ~80%, and BNIP1 protein level reduction by ~50% in patient 1 compared to control fibroblasts. The BNIP1 ortholog in drosophila, Sec. 20, regulates autophagy and lysosomal degradation. We assessed lysosome positioning and identified a decrease in lysosomes in the perinuclear region and an increase in the cell periphery in patient 1 cells. Immunofluorescence microscopy and immunoblotting demonstrated an increase in LC3B-positive structures and LC3B-II levels, respectively, in patient 1 fibroblasts under steady-state condition. Treatment of serum-starved fibroblasts with or without bafilomycin A1 identified significantly decreased autophagic flux in patient 1 cells. Our data suggest a block at the terminal stage of autolysosome formation and/or clearance in patient fibroblasts. BNIP1 together with RAB33B and VPS16, disease genes for Smith-McCort dysplasia 2 and a multisystem disorder with short stature, respectively, highlight the importance of autophagy in skeletal development. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Tess Holling
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Gandham SriLakshmi Bhavani
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Leonie von Elsner
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Hitesh Shah
- Department of Orthopedics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Neethukrishna Kausthubham
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | | | - Anju Shukla
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Geert R Mortier
- Center for Medical Genetics, University of Antwerp and Antwerp University Hospital, Antwerp, Belgium
| | - Thorsten Schinke
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Tatyana Danyukova
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Sandra Pohl
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Kerstin Kutsche
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Katta Mohan Girisha
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
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Zhang X, Liu H, Meena N, Li C, Zong G, Raben N, Puertollano R, Wang LX. Chemoenzymatic glycan-selective remodeling of a therapeutic lysosomal enzyme with high-affinity M6P-glycan ligands. Enzyme substrate specificity is the name of the game. Chem Sci 2021; 12:12451-12462. [PMID: 34603676 PMCID: PMC8480326 DOI: 10.1039/d1sc03188k] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 08/13/2021] [Indexed: 11/21/2022] Open
Abstract
Functionalization of therapeutic lysosomal enzymes with mannose-6-phosphate (M6P) glycan ligands represents a major strategy for enhancing the cation-independent M6P receptor (CI-MPR)-mediated cellular uptake, thus improving the overall therapeutic efficacy of the enzymes. However, the minimal high-affinity M6P-containing N-glycan ligands remain to be identified and their efficient and site-selective conjugation to therapeutic lysosomal enzymes is a challenging task. We report here the chemical synthesis of truncated M6P-glycan oxazolines and their use for enzymatic glycan remodeling of recombinant human acid α-glucosidase (rhGAA), an enzyme used for treatment of Pompe disease which is a disorder caused by a deficiency of the glycogen-degrading lysosomal enzyme. Structure-activity relationship studies identified M6P tetrasaccharide oxazoline as the minimal substrate for enzymatic transglycosylation yielding high-affinity M6P glycan ligands for the CI-MPR. Taking advantage of the substrate specificity of endoglycosidases Endo-A and Endo-F3, we found that Endo-A and Endo-F3 could efficiently deglycosylate the respective high-mannose and complex type N-glycans in rhGAA and site-selectively transfer the synthetic M6P N-glycan to the deglycosylated rhGAA without product hydrolysis. This discovery enabled a highly efficient one-pot deglycosylation/transglycosylation strategy for site-selective M6P-glycan remodeling of rhGAA to obtain a more homogeneous product. The Endo-A and Endo-F3 remodeled rhGAAs maintained full enzyme activity and demonstrated 6- and 20-fold enhanced binding affinities for CI-MPR receptor, respectively. Using an in vitro cell model system for Pompe disease, we demonstrated that the M6P-glycan remodeled rhGAA greatly outperformed the commercial rhGAA (Lumizyme) and resulted in the reversal of cellular pathology. This study provides a general and efficient method for site-selective M6P-glycan remodeling of recombinant lysosomal enzymes to achieve enhanced M6P receptor binding and cellular uptake, which could lead to improved overall therapeutic efficacy of enzyme replacement therapy.
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Affiliation(s)
- Xiao Zhang
- Department of Chemistry and Biochemistry, University of Maryland 8051 Regents Drive College Park Maryland 20742 USA
| | - Huiying Liu
- Department of Chemistry and Biochemistry, University of Maryland 8051 Regents Drive College Park Maryland 20742 USA
| | - Naresh Meena
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, NIH Bethesda Maryland 20892 USA
| | - Chao Li
- Department of Chemistry and Biochemistry, University of Maryland 8051 Regents Drive College Park Maryland 20742 USA
| | - Guanghui Zong
- Department of Chemistry and Biochemistry, University of Maryland 8051 Regents Drive College Park Maryland 20742 USA
| | - Nina Raben
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, NIH Bethesda Maryland 20892 USA
| | - Rosa Puertollano
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, NIH Bethesda Maryland 20892 USA
| | - Lai-Xi Wang
- Department of Chemistry and Biochemistry, University of Maryland 8051 Regents Drive College Park Maryland 20742 USA
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Graceffa V. Clinical Development of Cell Therapies to Halt Lysosomal Storage Diseases: Results and Lessons Learned. Curr Gene Ther 2021; 22:191-213. [PMID: 34323185 DOI: 10.2174/1566523221666210728141924] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 05/31/2021] [Accepted: 06/13/2021] [Indexed: 11/22/2022]
Abstract
Although cross-correction was discovered more than 50 years ago, and held the promise of drastically improving disease management, still no cure exists for lysosomal storage diseases (LSDs). Cell therapies hold the potential to halt disease progression: either a subset of autologous cells can be ex vivo/ in vivo transfected with the functional gene or allogenic wild type stem cells can be transplanted. However, majority of cell-based attempts have been ineffective, due to the difficulties in reversing neuronal symptomatology, in finding appropriate gene transfection approaches, in inducing immune tolerance, reducing the risk of graft versus host disease (GVHD) when allogenic cells are used and that of immune response when engineered viruses are administered, coupled with a limited secretion and uptake of some enzymes. In the last decade, due to advances in our understanding of lysosomal biology and mechanisms of cross-correction, coupled with progresses in gene therapy, ongoing pre-clinical and clinical investigations have remarkably increased. Even gene editing approaches are currently under clinical experimentation. This review proposes to critically discuss and compare trends and advances in cell-based and gene therapy for LSDs. Systemic gene delivery and transplantation of allogenic stem cells will be initially discussed, whereas proposed brain targeting methods will be then critically outlined.
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Affiliation(s)
- Valeria Graceffa
- Cellular Health and Toxicology Research Group (CHAT), Institute of Technology Sligo, Ash Ln, Bellanode, Sligo, Ireland
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