Therapy of adult Gaucher disease

Production of recombinant β-glucocerebrosidase in wild-type and glycoengineered transgenic Nicotiana benthamiana root cultures with different N-glycan profiles

Gaucher disease is an inherited lysosomal storage disorder caused by an insufficiency of active β-glucocerebrosidase (GCase). Exogenous recombinant GCase via enzyme replacement therapy is considered the most practical treatment for Gaucher disease. Mannose receptors mediate the efficient uptake of exogenous GCase into macrophages. Thus, terminal mannose residues on N-glycans are essential for the delivery of exogenous GCase. In this study, recombinant GCase was produced in root cultures of wild-type (WT) and glycoengineered transgenic Nicotiana benthamiana with downregulated N-acetylglucosaminyltransferase I expression. Root cultures of WT and glycoengineered transgenic N. benthamiana plants were successfully generated by the induction of plant hormones. Recombinant GCases produced in both root cultures possessed GCase enzyme activity. Purified GCases derived from both root cultures revealed different N-glycan profiles. The WT-derived GCase possessed the predominant plant-type N-glycans, which contain plant-specific sugars-linkages, specifically β1,2-xylose and α1,3-fucose residues. Notably, the mannosidic-type N-glycans with terminal mannose residues were abundant in the purified GCase derived from glycoengineered N. benthamiana root culture. This research provides a promising plant-based system for the production of recombinant GCase with terminal mannose residues on N-glycans.

Transient Production of Human β-Glucocerebrosidase With Mannosidic-Type N-Glycan Structure in Glycoengineered Nicotiana benthamiana Plants

Gaucher disease is an inherited lysosomal storage disorder caused by a deficiency of functional enzyme β-glucocerebrosidase (GCase). Recombinant GCase has been used in enzyme replacement therapy to treat Gaucher disease. Importantly, the terminal mannose N-glycan structure is essential for the uptake of recombinant GCase into macrophages via the mannose receptor. In this research, recombinant GCase was produced using Agrobacterium-mediated transient expression in both wild-type (WT) and N-acetylglucosaminyltransferase I (GnTI) downregulated Nicotiana benthamiana (ΔgntI) plants, the latter of which accumulates mannosidic-type N-glycan structures. The successfully produced functional GCase exhibited GCase enzyme activity. The enzyme activity was the same as that of the conventional mammalian-derived GCase. Notably, N-glycan analysis revealed that a mannosidic-type N-glycan structure lacking plant-specific N-glycans (β1,2-xylose and α1,3-fucose residues) was predominant in all glycosylation sites of purified GCase produced from ΔgntI plants. Our research provides a promising alternative plant line as a host for the production of recombinant GCase with a mannosidic-type N-glycan structure. This glycoengineered plant might be applicable to the production of other pharmaceutical proteins, especially mannose receptor targeted protein, for therapeutic uses.

The Importance of a Multidisciplinary Approach in the Management of a Patient with Type I Gaucher Disease

Managing the multisystemic symptoms of type I Gaucher Disease (GD) requires a multidisciplinary team approach that includes disease-specific treatments, as well as supportive care. This involves a range of medical specialists, general practitioners, supportive care providers, and patients. Phenotype classification and the setting of treatment goals are important for optimizing the management of type I GD, and for providing personalized care. The ability to classify disease severity using validated measurement tools allows the standardization of patient monitoring, and the measurement of disease progression and treatment response. Defining treatment goals is useful to provide a benchmark for assessing treatment response and managing the expectations of patients and their families. Although treatment goals will vary depending on disease severity, they include the stabilization, improvement or reversal (if possible) of clinical manifestations. Enzyme replacement therapy (ERT) is the standard care for patients with type I GD, but a novel substrate reduction therapy (SRT), Eliglustat, has demonstrated safety and efficacy in selected patients. To ensure that treatment goals are being achieved, regular and comprehensive follow up are necessary.

Hematopoietic stem cell transplantation for Gaucher disease

BACKGROUND

Gaucher disease is the most common lysosomal storage disorder caused by a deficiency of the enzyme glucocerebrosidase. Current treatment of the disease involves a choice from enzyme replacement therapy, substrate reduction therapy and hemotopoietic stem cell transplantation (HSCT). HSCT is a high risk procedure with possible long-term benefits in the regression of skeletal and neurological changes in people with Gaucher disease. This is an update of a previously published Cochrane Review.

OBJECTIVES

To determine the role of HSCT in people with Gaucher disease in relation to: mortality risk associated with the procedure; efficacy in modifying the course of the disease; and arrest or regression of neurological manifestations in neuronopathic forms (types 2 and 3).

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Inborn Errors of Metabolism Trials Register which comprises of references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings.Date of the most recent search of the Group's Haemoglobinopathies Trials Register: 19 January 2017.We also searched the websites: www.clinicaltrials.gov; WHO International Clinical Trials Registry Platform portal and www.genzymeclinicalresearch.com. Date of most recent search of these sites: 02 March 2017.

SELECTION CRITERIA

All randomised, quasi-randomised and controlled clinical trials comparing stem cell transplantation with enzyme replacement therapy, substrate reduction therapy, symptomatic treatment or no treatment in people with Gaucher disease of all ages.

DATA COLLECTION AND ANALYSIS

We independently assessed trials for inclusion, however, no relevant trials were identified.

MAIN RESULTS

Thirty two trials were identified by the searches; however, these were not suitable for inclusion in the review.

AUTHORS' CONCLUSIONS

HSCT is a form of treatment that offers the potential of permanent cure. However, there are no clinical trials that have assessed the safety and efficacy of this treatment in comparison to other conservative measures (enzyme replacement therapy, substrate reduction therapy) now in use.There are no trials included in the review and we have not identified any relevant trials up to March 2017. We therefore do not plan to update this review until new trials are published.

The combination of plant translational enhancers and terminator increase the expression of human glucocerebrosidase in Nicotiana benthamiana plants

Gaucher's disease is a lysosomal storage disorder caused by mutations in the gene encoding glucocerebrosidase (GCase). It is currently treated by enzyme replacement therapy using recombinant GCase expressed in mammalian cells. Plant production systems are among the most attractive alternatives for pharmaceutical protein production due to such advantages as low-cost, high-scalability, and safety from human pathogen contamination. Because of its high biomass yield, Nicotiana benthamiana could be an economical recombinant GCase production system. In this study, a translational enhancer and suitable terminator were utilized to obtain a powerful expression system for GCase production in N. benthamiana plants. Six plasmid constructs were used. The highest activity of 44.5units/mg protein (after subtraction of endogenous glucosidase activity of the wild-type plant) was observed in transgenic plants transformed with pAt-GC-HSP combined with a 5' untranslated region of the Arabidopsis alcohol dehydrogenase gene with the Arabidopsis heat shock protein terminator. These transgenic plant lines could pave the way to a stable plant-production system for low-cost, high-yield human GCase production.

Membrane anchors effectively traffic recombinant human glucocerebrosidase to the protein storage vacuole of Arabidopsis seeds but do not adequately control N-glycan maturation

Human glucocerebrosidase with vacuolar anchoring domains was targeted to protein storage vacuoles (PSVs) of Arabidopsis seeds, but unexpectedly via the Golgi complex. PSV-targeting to effectively avoid problematic N-glycans is protein dependent. Plant-specific N-glycosylation patterns elaborated within the Golgi complex are a major limitation of using plants to produce biopharmaceuticals as the presence of β1,2 xylose and/or α1,3 fucose residues on the recombinant glycoprotein can render the product immunogenic if administrated parenterally. A reporter protein fused to a vacuolar membrane targeting motif comprised of the BP-80 transmembrane domain (TMD), and the cytoplasmic tail (CT) of α-tonoplast intrinsic protein (α-TIP) is delivered to protein storage vacuoles (PSVs) of tobacco seeds by ER-derived transport vesicles that bypass the Golgi complex. This prompted us to investigate whether a pharmaceutical glycoprotein is targeted to PSVs using the same targeting sequences, thus avoiding the unwanted plant-Golgi-specific complex N-glycan modifications. The human lysosomal acid β-glucosidase (glucocerebrosidase; GCase) (EC 3.2.1.45) fused to the BP-80 TMD and α-TIP CT was produced in Arabidopsis thaliana wild-type (Col-0) seeds. The chimeric GCase became localized in PSVs but transited through the Golgi complex, as indicated by biochemical analyses of the recombinant protein's N-glycans. Our findings suggest that use of this PSV-targeting strategy to avoid problematic N-glycan maturation on recombinant therapeutic proteins is not consistently effective, as it is likely protein- and/or species-specific.

Gauchers disease--a reappraisal of hematopoietic stem cell transplantation

Hematopoietic stem cell transplantation (HSCT), first performed in 1984, was the first treatment approach for Gaucher's disease (GD) which had curative intent. The early successes in HSCT were soon eclipsed by the introduction of a highly effective enzyme replacement therapy (ERT), which has remained the single most widely used treatment. Experience with HSCT is limited to about 50 reported cases, mainly performed in the last century, with an overall survival around 85%. HSCT typically achieves complete correction of visceral and bony changes and can fully stabilize neurological features in otherwise progressive type II and III GD. ERT, in contrast, is completely safe and effective, but is limited by cost, incomplete resolution of visceral, hematological, and bony features in some patients, and lack of neurological correction in type II and III disease. In this review, we summarize and compare HSCT and ERT. With 20 years of experience of ERT, its limitations as well as its advantages are now well delineated. Meanwhile progress in HSCT over the last decade suggests that transplantation would today represent a very safe curative approach for GD offering one time complete correction of the disease, contrasting with the lifelong need for ERT with its associated expense and dependence on sophisticated drug manufacture. Additionally, unlike ERT, HSCT can be beneficial for neurological forms of GD. We conclude that the time has come to re-evaluate HSCT in selected patients with GD where ERT is less likely to fully eradicate symptoms of the disease.

Hematopoietic stem cell transplantation for Gaucher disease

BACKGROUND

Gaucher disease is the most common lysosomal storage disorder caused by a deficiency of the enzyme glucocerebrosidase. Current treatment of the disease involves a choice among enzyme replacement therapy, substrate reduction therapy and stem cell transplantation. Stem cell transplantation is a high risk procedure with possible long-term benefits in the regression of skeletal and neurological changes in people with Gaucher disease.

OBJECTIVES

To determine the role of hematopoietic stem cell transplantation in people with Gaucher disease in relation to: mortality risk associated with the procedure; efficacy in modifying the course of the disease; and arrest or regression of neurological manifestations in neuropathic forms (Types 2 and 3).

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Inborn Errors of Metabolism Trials Register which comprises of references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings.Date of the most recent search of the Group's Haemoglobinopathies Trials Register: 26 March 2012.We also searched the websites www.clinicaltrials.gov and www.genzymeclinicalresearch.com. Date of most recent search of these sites: 16 February 2012.

SELECTION CRITERIA

All randomised, quasi-randomised and controlled clinical trials comparing stem cell transplantation with enzyme replacement therapy, substrate reduction therapy, symptomatic treatment or no treatment in people with Gaucher disease of all ages.

DATA COLLECTION AND ANALYSIS

We independently assessed trials for inclusion, however, no relevant trials were identified.

MAIN RESULTS

Twelve trials were identified by the searches, however, these were not suitable for inclusion in the review.

AUTHORS' CONCLUSIONS

Stem cell transplantation is a form of treatment that offers the potential of permanent cure. However, there are no clinical trials that have assessed the safety and efficacy of stem cell transplantation in comparison to other conservative measures (enzyme replacement therapy, substrate reduction therapy) now in use.

Production of active human glucocerebrosidase in seeds of Arabidopsis thaliana complex-glycan-deficient (cgl) plants

There is a clear need for efficient methods to produce protein therapeutics requiring mannose-termination for therapeutic efficacy. Here we report on a unique system for production of active human lysosomal acid β-glucosidase (glucocerebrosidase, GCase, EC 3.2.1.45) using seeds of the Arabidopsis thaliana complex-glycan-deficient (cgl) mutant, which are deficient in the activity of N-acetylglucosaminyl transferase I (EC 2.4.1.101). Gaucher disease is a prevalent lysosomal storage disease in which affected individuals inherit mutations in the gene (GBA1) encoding GCase. A gene cassette optimized for seed expression was used to generate the human enzyme in seeds of the cgl (C5) mutant, and the recombinant GCase was mainly accumulated in the apoplast. Importantly, the enzymatic properties including kinetic parameters, half-maximal inhibitory concentration of isofagomine and thermal stability of the cgl-derived GCase were comparable with those of imiglucerase, a commercially available recombinant human GCase used for enzyme replacement therapy in Gaucher patients. N-glycan structural analyses of recombinant cgl-GCase showed that the majority of the N-glycans (97%) were mannose terminated. Additional purification was required to remove ∼15% of the plant-derived recombinant GCase that possessed potentially immunogenic (xylose- and/or fucose-containing) N-glycans. Uptake of cgl-derived GCase by mouse macrophages was similar to that of imiglucerase. The cgl seed system requires no addition of foreign (non-native) amino acids to the mature recombinant GCase protein, and the dry transgenic seeds represent a stable repository of the therapeutic protein. Other strategies that may completely prevent plant-like complex N-glycans are discussed, including the use of a null cgl mutant.

Lysosomal storage diseases as differential diagnosis of hepatosplenomegaly

In adults, elevated transaminases and hepatomegaly, often mild, with moderate to massive idiopathic splenomegaly might hint to a lysosomal storage disease (LSD). In most of these cases, hepatosplenomegaly does not eventually lead to cirrhosis, hepatocellular carcinoma or cholestasis. Nevertheless, the hepatic clinical findings might be the incentive for the patient to present at the physician's office. Many of the currently known >50 lysosomal storage diseases might manifest in liver: out of these, the most important ones in adults are: Gaucher disease, cholesterol ester storage disease (CESD) and the Niemann-Pick diseases. An increase of plasma chitotriosidase should alert the physician for the presence of an LSD. For Gaucher's disease, enzyme supplementation and substrate deprivation constitute effective therapeutic options. Fabry's disease, the most prevalent lysosomal storage disease, does usually not affect the liver, but causes painful episodes of hands' or feet pain (acroparesthesias), left ventricular hypertrophy, renal failure, early stroke and decreased life expectancy. The emerging advent of effective therapeutic options and the cumulative prevalence of lysosomal storage diseases urge the hepatologist to add these diagnostic pathways to the clinical repertoire.

New biotechnological and nanomedicine strategies for treatment of lysosomal storage disorders

This review discusses the multiple bio- and nanotechnological strategies developed in the last few decades for treatment of a group of fatal genetic diseases termed lysosomal storage disorders. Some basic foundation on the biomedical causes and social and clinical relevance of these diseases is provided. Several treatment modalities, from those currently available to novel therapeutic approaches under development, are also discussed; these include gene and cell therapies, substrate reduction therapy, chemical chaperones, enzyme replacement therapy, multifunctional chimeras, targeting strategies, and drug carrier approaches.

Musculoskeletal complications encountered in the lysosomal storage disorders

The lysosomal storage disorders are a heterogeneous group of inherited metabolic diseases resulting from defects in the degradation or transport of several distinct by-products of cellular turnover. The various subtypes are characterized by multi-systemic involvement; the wide range in patient ages at symptom onset is only partly explained by the underlying mutation(s). Neurodegenerative features and musculoskeletal complications are often seen in the most severe variants, and are features of the disease that have the most significant impact on patients' physical and functional well-being. Until recently, the care of affected individuals relied mainly on palliative or supportive measures. The introduction of therapies directed at correcting the primary defect (i.e., deficient enzyme activity) in several of these disorders has led to modification of the phenotype and natural history or disease course; however, clinical problems arising from brain and bone involvement remain major sources of morbidity. Factors that might influence therapeutic outcome include pre-existing pathology at the time of treatment initiation, drug access to tissues sites of pathology, and - in the case of enzyme therapy - antibody formation. Increasing understanding of the pathogenesis or relevant mechanism(s) of diseases is providing insights into additional therapeutic targets, enabling the potential for optimized patient outcomes with the use of adjunctive or supplemental agents. Physical and occupational therapy remain critical components of a comprehensive approach to patient care.

Hematopoietic stem cell transplantation for Gaucher disease

BACKGROUND

Gaucher disease is the most common lysosomal storage disorder caused by a deficiency of the enzyme glucocerebrosidase. Current treatment of the disease involves a choice among enzyme replacement therapy, substrate reduction therapy and stem cell transplantation. Stem cell transplantation is a high risk procedure with possible long-term benefits in the regression of skeletal and neurological changes in people with Gaucher disease.

OBJECTIVES

To determine the role of hematopoietic stem cell transplantation in people with Gaucher disease in relation to: mortality risk associated with the procedure; efficacy in modifying the course of the disease; and arrest or regression of neurological manifestations in neuropathic forms (Types 2 and 3).

SEARCH STRATEGY

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Inborn Errors of Metabolism Trials Register which comprises of references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. We also searched the websites www.clinicaltrials.gov and www.genzymeclinicalresearch.com.Date of the most recent search of the Group's Trials Register: June 2008.

SELECTION CRITERIA

All randomised, quasi-randomised and controlled clinical trials comparing stem cell transplantation with enzyme replacement therapy, substrate reduction therapy, symptomatic treatment or no treatment in people with Gaucher disease of all ages.

DATA COLLECTION AND ANALYSIS

We independently assessed trials for inclusion, however, no relevant trials were identified.

MAIN RESULTS

Eight trials were identified by the initial search, however, these were not suitable for inclusion in the review.

AUTHORS' CONCLUSIONS

Stem cell transplantation is a form of treatment that offers the potential of permanent cure. However, there are no clinical trials that have assessed the safety and efficacy of stem cell transplantation in comparison to other conservative measures (enzyme replacement therapy, substrate reduction therapy) now in use.

Splenomegaly as a primary manifestation of Gaucher disease in a young adult woman

Gaucher disease is the most common lysosomal storage disease. It is caused by the defective activity of acid β-glucosidase, which results in the accumulation of lipid glucocerebroside in macrophages throughout the body. In this case report we describe the case of a young adult woman with splenomegaly as the primary manifestation of this pathology. This is a case of type 1 Gaucher disease because there is a lack of primary neurological involvement but we have, instead, an age-independent involvement of the visceral organs. It is very important to classify or characterize these patients in a precise manner and to make a complete diagnosis with the help of the many diagnostic resources now at our disposal, especially with genetics, radiology and new techniques of advanced microscopy, also because Gaucher disease requires a long and complex management from early life to adulthood.