Glycosylation-independent Lysosomal Targeting of Acid α-Glucosidase Enhances Muscle Glycogen Clearance in Pompe Mice

Maga, John A.; Zhou, Jianghong; Kambampati, Ravi; Peng, Susan; Wang, Xu; Bohnsack, Richard N.; Thomm, Angela; Golata, Sarah; Tom, Peggy; Dahms, Nancy M.; Byrne, Barry J.; LeBowitz, Jonathan H.

doi:10.1074/jbc.m112.438663

Cited by 102 publications

(110 citation statements)

References 39 publications

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“…Also, it may be reasonable to expect that ERT and chaperone coformulation for intravenous administration may be as effective. In principle, the enhancing effect of chaperones on ERT may also apply to second-generation recombinant enzymes that are presently under evaluation, 30,31 or in combination with strategies aimed at improving muscle targeting of recombinant GAA. 32,33 This study did not address the question as to whether this effect of chaperones on ERT results in greater therapeutic efficacy of ERT.…”

Section: Discussionmentioning

confidence: 99%

A Chaperone Enhances Blood α-Glucosidase Activity in Pompe Disease Patients Treated With Enzyme Replacement Therapy

et al. 2014

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Enzyme replacement therapy is currently the only approved treatment for Pompe disease, due to acid α-glucosidase deficiency. Clinical efficacy of this approach is variable, and more effective therapies are needed. We showed in preclinical studies that chaperones stabilize the recombinant enzyme used for enzyme replacement therapy. Here, we evaluated the effects of a combination of enzyme therapy and a chaperone on α-glucosidase activity in Pompe disease patients. α-Glucosidase activity was analyzed by tandem-mass spectrometry in dried blood spots from patients treated with enzyme replacement therapy, either alone or in combination with the chaperone N-butyldeoxynojirimycin given at the time of the enzyme infusion. Thirteen patients with different presentations (3 infantile-onset, 10 late-onset) were enrolled. In 11 patients, the combination treatment resulted in α-glucosidase activities greater than 1.85-fold the activities with enzyme replacement therapy alone. In the whole patient population, α-glucosidase activity was significantly increased at 12 hours (2.19-fold, P = 0.002), 24 hours (6.07-fold, P = 0.001), and 36 hours (3.95-fold, P = 0.003). The areas under the curve were also significantly increased (6.78-fold, P = 0.002). These results suggest improved stability of recombinant α-glucosidase in blood in the presence of the chaperone.

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Section: Discussionmentioning

confidence: 99%

A Chaperone Enhances Blood α-Glucosidase Activity in Pompe Disease Patients Treated With Enzyme Replacement Therapy

et al. 2014

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“…A competitive receptor binding assay was used to measure the binding affinity to the IGFII receptor fragment consisting of domains 10-13 (21). The fragment (0.5 μg/100 μL/well) was coated onto a Reacti-Bind plate (Thermo Scientific) overnight at room temperature, followed by a blocking step (SuperBlock T20 Blocking buffer; Thermo Scientific) for 1 h. The plate was incubated with varying concentrations of NAGLU, NAGLU-IGFII, or IGFII (Cell Sciences) in the presence of 3-8 nM biotinylated IGFII (Cell Sciences) for 2 h at room temperature.…”

Section: Methodsmentioning

confidence: 99%

“…In addition, the β-glucuronidaseand α-glucosidase-IGFII fusion proteins, administered i.v. to deficient mice, were found to be taken up by major somatic organs and muscles, respectively, in which they functioned to reduce storage and pathology (20,21). On the basis of these promising earlier studies, we treated the brain of the MPS IIIB mouse by administering a NAGLU-IGFII fusion protein directly into the left cerebral ventricle, bypassing the blood-brain barrier.…”

Section: Significancementioning

confidence: 99%

Delivery of an enzyme-IGFII fusion protein to the mouse brain is therapeutic for mucopolysaccharidosis type IIIB

Kan

Aoyagi-Scharber

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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Mucopolysaccharidosis type IIIB (MPS IIIB, Sanfilippo syndrome type B) is a lysosomal storage disease characterized by profound intellectual disability, dementia, and a lifespan of about two decades. The cause is mutation in the gene encoding α-N-acetylglucosaminidase (NAGLU), deficiency of NAGLU, and accumulation of heparan sulfate. Impediments to enzyme replacement therapy are the absence of mannose 6-phosphate on recombinant human NAGLU and the bloodbrain barrier. To overcome the first impediment, a fusion protein of recombinant NAGLU and a fragment of insulin-like growth factor II (IGFII) was prepared for endocytosis by the mannose 6-phosphate/ IGFII receptor. To bypass the blood-brain barrier, the fusion protein ("enzyme") in artificial cerebrospinal fluid ("vehicle") was administered intracerebroventricularly to the brain of adult MPS IIIB mice, four times over 2 wk. The brains were analyzed 1-28 d later and compared with brains of MPS IIIB mice that received vehicle alone or control (heterozygous) mice that received vehicle. There was marked uptake of the administered enzyme in many parts of the brain, where it persisted with a half-life of approximately 10 d. Heparan sulfate, and especially disease-specific heparan sulfate, was reduced to control level. A number of secondary accumulations in neurons [β-hexosaminidase, LAMP1(lysosome-associated membrane protein 1), SCMAS (subunit c of mitochondrial ATP synthase), glypican 5, β-amyloid, P-tau] were reduced almost to control level. CD68, a microglial protein, was reduced halfway. A large amount of enzyme also appeared in liver cells, where it reduced heparan sulfate and β-hexosaminidase accumulation to control levels. These results suggest the feasibility of enzyme replacement therapy for MPS IIIB. M ucopolysaccharidosis type III (MPS III, Sanfilippo syndrome) is a heritable lysosomal disorder of heparan sulfate degradation, divided into four types (A-D), depending on the enzyme deficiency (1, 2). All four MPS III types are characterized by severe neurologic problems and relatively mild somatic ones. Profound intellectual disability that progresses to dementia, behavioral disturbances, and death in the second or third decade bring untold suffering to the MPS III patients and their families. Despite the dire need, treatment for the MPS III disorders has lagged behind other MPS diseases. Hematopoietic stem cell transplantation, an effective procedure for MPS I patients with CNS involvement (3), is not effective for MPS III (4). Enzyme replacement therapy has been available for some years for several MPS with extensive somatic involvement [MPS I (5, 6), II (7), and VI (8)], or is newly approved (MPS IVA), or in clinical trial (MPS VII). However, development of enzyme replacement for MPS III did not seem promising because access to therapeutic enzyme to brain parenchyma would be limited by the blood-brain barrier. With respect to MPS IIIB, a deficiency of α-N-acetylglucosaminidase, EC 3.2.1.50) (NAGLU), there is an additional difficulty in that, in contrast to ...

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“…Cells were then washed 4 times with cold PBS and fixed with 4% paraformaldehyde at room temperature for 15 min. Immunofluorescence was done as described [22]. Briefly, fixed cells were permeabilized for 15 min with 0.1% Triton X-100 and blocked with 5% goat serum in DPBS for 30 min, then incubated with rabbit anti-Lamp2 antibody (ab37024) (1:500 in blocking buffer) for 1 h, then with Alexa Fluorconjugated secondary antibodies (Invitrogen) for 1 h. Fab (of mouse origin) was visualized directly using an Alexa Fluor-conjugated anti-mouse secondary antibody (Invitrogen).…”

Section: Immunofluorescencementioning

confidence: 99%

Antibody-mediated enzyme replacement therapy targeting both lysosomal and cytoplasmic glycogen in Pompe disease

Sun

Armstrong

et al. 2017

J Mol Med

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Pompe disease is characterized by accumulation of both lysosomal and cytoplasmic glycogen primarily in skeletal and cardiac muscles. Mannose-6-phosphate receptor-mediated enzyme replacement therapy (ERT) with recombinant human acid α-glucosidase (rhGAA) targets the enzyme to lysosomes and thus is unable to digest cytoplasmic glycogen. Studies have shown that anti-DNA antibody 3E10 penetrates living cells and delivers Bcargo^proteins to the cytosol or nucleus via equilibrative nucleoside transporter ENT2. We speculate that 3E10-mediated ERT with GAA will target both lysosomal and cytoplasmic glycogen in Pompe disease. A fusion protein (FabGAA) containing a humanized Fab fragment derived from the murine 3E10 antibody and the 110 kDa human GAA precursor was constructed and produced in CHO cells. Immunostaining with an anti-Fab antibody revealed that the Fab signals did not co-localize with the lysosomal marker LAMP2 in cultured L6 myoblasts or Pompe patient fibroblasts after incubation with FabGAA. Western blot with an anti-GAA antibody showed presence of the 150 kDa full-length FabGAA in the cell lysates, in addition to the 95-and 76 kDa processed forms of GAA that were also seen in the rhGAA-treated cells. Blocking of mannose-6-phosphate receptor with mannose-6-phosphate markedly reduced the 95-and the 76 kDa forms but not the 150 kDa form.

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Glycosylation-independent Lysosomal Targeting of Acid α-Glucosidase Enhances Muscle Glycogen Clearance in Pompe Mice

Cited by 102 publications

References 39 publications

A Chaperone Enhances Blood α-Glucosidase Activity in Pompe Disease Patients Treated With Enzyme Replacement Therapy

A Chaperone Enhances Blood α-Glucosidase Activity in Pompe Disease Patients Treated With Enzyme Replacement Therapy

Delivery of an enzyme-IGFII fusion protein to the mouse brain is therapeutic for mucopolysaccharidosis type IIIB

Antibody-mediated enzyme replacement therapy targeting both lysosomal and cytoplasmic glycogen in Pompe disease

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