Gaucher disease

In Utero Gene Therapy and its Application in Genetic Hearing Loss

For monogenic genetic diseases, in utero gene therapy (IUGT) shows the potential for early prevention against irreversible and lethal pathological changes. Moreover, animal models have also demonstrated the effectiveness of IUGT in the treatment of coagulation disorders, hemoglobinopathies, neurogenetic disorders, and metabolic and pulmonary diseases. For major alpha thalassemia and severe osteogenesis imperfecta, in utero stem cell transplantation has entered the phase I clinical trial stage. Within the realm of the inner ear, genetic hearing loss significantly hampers speech, cognitive, and intellectual development in children. Nowadays, gene therapies offer substantial promise for deafness, with the success of clinical trials in autosomal recessive deafness 9 using AAV-OTOF gene therapy. However, the majority of genetic mutations that cause deafness affect the development of cochlear structures before the birth of fetuses. Thus, gene therapy before alterations in cochlear structure leading to hearing loss has promising applications. In this review, addressing advances in various fields of IUGT, the progress, and application of IUGT in the treatment of genetic hearing loss are focused, in particular its implementation methods and unique advantages.

Gaucher Disease: A Glance from a Medicinal Chemistry Perspective

Rare diseases are particular pathological conditions affecting a limited number of people and few drugs are known to be effective as therapeutic treatment. Gaucher disease, caused by a deficiency of the lysosomal enzyme glucocerebrosidase, belongs to this class of disorders, and it is considered the most common among the Lysosomal Storage Diseases. The two main therapeutic approaches are the Enzyme Replacement Therapy (ERT) and the Substrate Reduction Therapy (SRT). ERT, consisting in replacing the defective enzyme by administering a recombinant enzyme, is effective in alleviating the visceral symptoms, hallmarks of the most common subtype of the disease whereas it has no effects when symptoms involve CNS, since the recombinant protein is unable to significantly cross the Blood Brain Barrier. The SRT strategy involves inhibiting glucosylceramide synthase (GCS), the enzyme responsible for the production of the associated storage molecule. The rational design of new inhibitors of GCS has been hampered by the lack of either the crystal structure of the enzyme or an in-silico model of the active site which could provide important information regarding the interactions of potential inhibitors with the target, but, despite this, interesting results have been obtained and are herein reviewed.

Eldar Y. A Deep-Learning Approach to Spleen Volume Estimation in Patients with Gaucher Disease

The enlargement of the liver and spleen (hepatosplenomegaly) is a common manifestation of Gaucher disease (GD). An accurate estimation of the liver and spleen volumes in patients with GD, using imaging tools such as magnetic resonance imaging (MRI), is crucial for the baseline assessment and monitoring of the response to treatment. A commonly used method in clinical practice to estimate the spleen volume is the employment of a formula that uses the measurements of the craniocaudal length, diameter, and thickness of the spleen in MRI. However, the inaccuracy of this formula is significant, which, in turn, emphasizes the need for a more precise and reliable alternative. To this end, we employed deep-learning techniques, to achieve a more accurate spleen segmentation and, subsequently, calculate the resulting spleen volume with higher accuracy on a testing set cohort of 20 patients with GD. Our results indicate that the mean error obtained using the deep-learning approach to spleen volume estimation is 3.6 ± 2.7%, which is significantly lower than the common formula approach, which resulted in a mean error of 13.9 ± 9.6%. These findings suggest that the integration of deep-learning methods into the clinical routine practice for spleen volume calculation could lead to improved diagnostic and monitoring outcomes.

Psychiatric manifestations of inborn errors of metabolism: A systematic review

Inborn errors of metabolism (IEMs) are characterized by deficits in metabolic enzymes as a result of an inherited disease, leading to the accumulation or decreased excretion of proteins, carbohydrates and lipids. Although IEMs are often diagnosed during childhood, adolescent and adult onset variants may be accompanied by less somatic and more psychiatric manifestations, which often hampers recognition by psychiatrists of the distinction between a primary and secondary psychiatric disorder. To help clinicians in the diagnostic process, we aimed to provide an overview of psychiatric manifestations in IEMs. Our literature search yielded 4380 records in total, of which 88 studies were included in the qualitative synthesis. Reported psychiatric disorders in adolescent and adult IEMs included depression, anxiety disorder, psychosis, attention deficit hyperactivity disorder, autism spectrum disorder, bipolar disorder and obsessive-compulsive disorder as assessed by semi-structured diagnostic interviews and validated questionnaires. A diagnostic screener and multidisciplinary IEM clinics are proposed to help clinicians during the diagnostic process, to prevent diagnostic delay and to raise awareness of the psychiatric manifestations among IEMs.

Liposomal formulations for treating lysosomal storage disorders

Lysosomal storage disorders (LSD) are a group of rare life-threatening diseases caused by a lysosomal dysfunction, usually due to the lack of a single enzyme required for the metabolism of macromolecules, which leads to a lysosomal accumulation of specific substrates, resulting in severe disease manifestations and early death. There is currently no definitive cure for LSD, and despite the approval of certain therapies, their effectiveness is limited. Therefore, an appropriate nanocarrier could help improve the efficacy of some of these therapies. Liposomes show excellent properties as drug carriers, because they can entrap active therapeutic compounds offering protection, biocompatibility, and selectivity. Here, we discuss the potential of liposomes for LSD treatment and conduct a detailed analysis of promising liposomal formulations still in the preclinical development stage from various perspectives, including treatment strategy, manufacturing, characterization, and future directions for implementing liposomal formulations for LSD.

Mass spectrometry-based proteomics in neurodegenerative lysosomal storage disorders

The major function of the lysosome is to degrade unwanted materials such as lipids, proteins, and nucleic acids; therefore, deficits of the lysosomal system can result in improper degradation and trafficking of these biomolecules. Diseases associated with lysosomal failure can be lethal and are termed lysosomal storage disorders (LSDs), which affect 1 in 5000 live births collectively. LSDs are inherited metabolic diseases caused by mutations in single lysosomal and non-lysosomal proteins and resulting in the subsequent accumulation of macromolecules within. Most LSD patients present with neurodegenerative clinical symptoms, as well as damage in other organs. The discovery of new biomarkers is necessary to understand and monitor these diseases and to track therapeutic progress. Over the past ten years, mass spectrometry (MS)-based proteomics has flourished in the biomarker studies in many diseases, including neurodegenerative, and more specifically, LSDs. In this review, biomarkers of disease pathophysiology and monitoring of LSDs revealed by MS-based proteomics are discussed, including examples from Niemann-Pick disease type C, Fabry disease, neuronal ceroid-lipofuscinoses, mucopolysaccharidosis, Krabbe disease, mucolipidosis, and Gaucher disease.

Etiology of avascular osteonecrosis of the femoral head

Avascular osteonecrosis of the femoral head (ONFH) is one of the causes of hip pain that clinicians need to know about. In many cases, it is a fortuitous discovery when pelvic X-rays is performed for another reason. In the other cases, pain reveals the disease. For the rheumatologist, a major part of the job is to look for a cause. An etiology can be found to ONFH in about 70% of the cases. Some of them are evident and the context give the diagnosis (corticosteroids, alcohol abuse…). However, in many cases, additional tests to imaging are required to make the causal diagnosis. In some cases, the treatment of the cause can prevent the recurrence of the disease.

Influence of a 4'-substituent on the efficiency of flavonol-based fluorescent indicators of β-glycosidase activity

This article presents novel fluorescent probes, based on the excited-state intramolecular proton transfer (ESIPT) phenomenon and flavonols, sensitive to the action of specific glycosidases. 4'-Substituted flavonols were synthesized, using various approaches, and glycosylated with d-glucose, N-acetyl-d-glucosamine and d-glucuronic acid. Evaluation of the β-glycosidase activities was performed in neutral and acidic pH. In all the cases examined, an acidic environment accelerated enzymatic hydrolysis. It was demonstrated that the 4'-chloroflavonyl glycosides of all sugars tested, both in neutral and acidic pH, are the ones most sensitive to the presence of hydrolase. In turn, 4'-dimethylaminoflavonyl glucoside is not sensitive to glucosidase action at all. Generally, the rate of enzymatic hydrolysis increases as the electron-withdrawing nature of the 4'-substituent increases. An exception is the trifluoromethyl group which, in spite of having the most favourable Hammett constant, does not contribute enough to increase the rate of hydrolysis of its glucoside. The presented experimental results are supported by the electrostatic potential (ESP) analysis and related to the mechanisms of glycoside bond enzymatic hydrolysis.

Osteoimmunology: The Conceptual Framework Unifying the Immune and Skeletal Systems

The immune and skeletal systems share a variety of molecules, including cytokines, chemokines, hormones, receptors, and transcription factors. Bone cells interact with immune cells under physiological and pathological conditions. Osteoimmunology was created as a new interdisciplinary field in large part to highlight the shared molecules and reciprocal interactions between the two systems in both heath and disease. Receptor activator of NF-κB ligand (RANKL) plays an essential role not only in the development of immune organs and bones, but also in autoimmune diseases affecting bone, thus effectively comprising the molecule that links the two systems. Here we review the function, gene regulation, and signal transduction of osteoimmune molecules, including RANKL, in the context of osteoclastogenesis as well as multiple other regulatory functions. Osteoimmunology has become indispensable for understanding the pathogenesis of a number of diseases such as rheumatoid arthritis (RA). We review the various osteoimmune pathologies, including the bone destruction in RA, in which pathogenic helper T cell subsets [such as IL-17-expressing helper T (Th17) cells] induce bone erosion through aberrant RANKL expression. We also focus on cellular interactions and the identification of the communication factors in the bone marrow, discussing the contribution of bone cells to the maintenance and regulation of hematopoietic stem and progenitors cells. Thus the time has come for a basic reappraisal of the framework for understanding both the immune and bone systems. The concept of a unified osteoimmune system will be absolutely indispensable for basic and translational approaches to diseases related to bone and/or the immune system.

The role of high density lipoprotein in Type 1 Gaucher disease

Type I Gaucher Disease (GD1) is known to be associated with hypocholesterolemia and reduced levels of low density lipoprotein (LDL) and high density lipoprotein (HDL). In this study we aimed to correlate disease severity with HDL levels and to evaluate the effect of enzyme replacement therapy (ERT) on HDL levels as well as estimating the frequency of cardiovascular events in GD. Two groups of GD1 patients were evaluated: 30 untreated and 36 patients on ERT. Disease severity, biomarkers of GD and lipid levels were evaluated in the two groups. The Zimran Severity Score Index (SSI) was used to estimate disease severity and the effect of ERT on HDL levels was evaluated, as well as the frequency of cardiovascular disease. GD1 patients with more severe disease (SSI median 11) had significantly lower levels of HDL (median 23mg/dL), compared to patients with milder (SSI median 4.5) disease (median 37mg/dL p=0.001). HDL levels increased after ERT. Despite lower HDL levels in patients with more severe disease, a low frequency of cardiovascular events was detected. HDL level should be used in GD as a biomarker for diagnosis, monitoring and estimation of ERT effect.

Enzyme Replacement or Substrate Reduction? A Review of Gaucher Disease Treatment Options

BACKGROUND

Gaucher disease is a rare lysosomal storage disease resulting from a deficiency or reduced activity in the acid β-glucocosidase enzyme. Only 1 treatment option was available for 15 years, but several new treatment options have come to market since 2003.

OBJECTIVE

The article will detail the pathophysiology and review current therapies in the literature for all 3 major clinical types of Gaucher disease, with a focus on considerations for selecting therapy in type 1 disease.

METHODS

Extracted and summarized applicable studies and reviews from Cochrane Review, ClinicalTrials.gov, CINAHL, IPA, and PubMed.

RESULTS

Enzyme replacement therapy is preferred for the management of Gaucher disease. Current literature does not favor any enzyme replacement product over another. However, velaglucerase alfa and taliglucerase alfa theoretically have a lower risk of immunogenicity reactions compared with imiglucerase. Alternative treatments for type 1 disease include substrate reduction therapy; however, these treatments require evaluation of patient-specific variables (eg, genotype evaluation, renal function) and consideration of adverse effect and dosing profiles. Evaluation of current literature found no substrate reduction therapy is preferred over another. There are no approved therapies for type 2 and type 3 disease, but enzyme replacement therapy may be used with limited efficacy for symptom management.

CONCLUSION

Enzyme replacement therapy is preferred for treating type 1 Gaucher disease and substrate replacement therapy may be considered in patients who do not tolerate or cannot receive enzyme replacement therapy.

Identification of novel splice site mutation IVS9 + 1(G > A) and novel complex allele G355R/R359X in Type 1 Gaucher patients heterozygous for mutation N370S

Gaucher disease is an autosomal recessive lysosomal storage disorder resulting from deficient glucocerebrosidase activity. More than 350 mutations that cause Gaucher disease have been described to date. Novel mutations can potentially provide insight into the glucocerebrosidase structure–function relationship and biochemical basis of the disease. Here, we report the identification of two novel mutations in two unrelated patients with type I (non-neuronopathic) Gaucher disease: 1) a splice site mutation IVS9 + 1G > A; and (2) a complex allele (cis) G355R/R359X. Both patients have a common N370S mutation in the other allele. The splice site mutation results from an intronic base substitution (G to A, c.1328 + 1, g.5005) at the donor splice site of exon and intron 9. The complex allele results from two point mutations in exon 8 of glucocerebrosidase (G to C at c.1180, g.4396, and T to C at c. 1192, g.4408) substituting glycine by arginine (G355R) and arginine by a premature termination (R359X), respectively. In order to demonstrate that G355R/R359X are in cis arrangement, PCR-amplified glucocerebrosidase exon 8 genomic DNA from the patient was cloned into the vector pJET1.2 in Escherichia coli TOP10® strain. Out of the 15 clones that were sequence analyzed, 10 contained the normal allele sequence and 5 contained the complex allele G355R/R359X sequence showing both mutations in cis arrangement. Restriction fragment length polymorphism analysis using Hph1 restriction endonuclease digest was established for the IVS9 + 1G > A mutation for confirmation and efficient identification of this mutation in future patients. Past literature suggests that mutations affecting splicing patterns of the glucocerebrosidase transcript as well as mutations in Gaucher complex alleles are detrimental to enzyme activity. However, compound heterozygosity with N370S, a mild mutation, will lead to a mild phenotype. The cases reported here support these past findings.

Bone geometry, bone mineral density, and micro-architecture in patients with myelofibrosis: a cross-sectional study using DXA, HR-pQCT, and bone turnover markers

Primary myelofibrosis (MF) is a severe chronic myeloproliferative neoplasm, progressing towards a terminal stage with insufficient haematopoiesis and osteosclerotic manifestations. Whilst densitometry studies have showed MF patients to have elevated bone mineral density, data on bone geometry and micro-structure assessed with non-invasive methods are lacking. We measured areal bone mineral density (aBMD) using dual-energy X-ray absorptiometry (DXA). Bone geometry, volumetric BMD, and micro-architecture were measured using high-resolution peripheral quantitative computed tomography (HR-pQCT). We compared the structural parameters of bones by comparing 18 patients with MF and healthy controls matched for age, sex, and height. Blood was analysed for biochemical markers of bone turnover in patients with MF. There were no significant differences in measurements of bone geometry, volumetric bone mineral density, and micro-structure between MF patients and matched controls. Estimated bone stiffness and bone strength were similar between MF patients and controls. The level of pro-collagen type 1 N-terminal pro-peptide (P1NP) was significantly increased in MF, which may indicate extensive collagen synthesis, one of the major diagnostic criteria in MF. We conclude that bone mineral density, geometry, and micro-architecture in this cohort of MF patients are comparable with those in healthy individuals.

Intravenous injections in neonatal mice

Intravenous injection is a clinically applicable manner to deliver therapeutics. For adult rodents and larger animals, intravenous injections are technically feasible and routine. However, some mouse models can have early onset of disease with a rapid progression that makes administration of potential therapies difficult. The temporal (or facial) vein is just anterior to the ear bud in mice and is clearly visible for the first two days after birth on either side of the head using a dissecting microscope. During this window, the temporal vein can be injected with volumes up to 50 μl. The injection is safe and well tolerated by both the pups and the dams. A typical injection procedure is completed within 1-2 min, after which the pup is returned to the home cage. By the third postnatal day the vein is difficult to visualize and the injection procedure becomes technically unreliable. This technique has been used for delivery of adeno-associated virus (AAV) vectors, which in turn can provide almost body-wide, stable transgene expression for the life of the animal depending on the viral serotype chosen.

Modeling changes in biomarkers in Gaucher disease patients receiving enzyme replacement therapy using a pathophysiological model

Background

Gaucher disease (GD) is a rare recessively inherited disorder caused by deficiency of a lysosomal enzyme, glucocerebrosidase. Accumulation of glucosylceramide or glucosylsphingosine in macrophages leads to increased production of ferritin and chitotriosidase and to decreases in hemoglobin concentration and platelet count, which are used as blood biomarkers. GD is treated by enzyme replacement therapy (ERT) or, sometimes by substrate reduction therapy. However, no physiological model for analysis of biomarkers change during ERT has been proposed. We aimed to develop a pathophysiological model to analyze biomarker’s response to ERT and several covariates impact.

Methods

Changes in blood ferritin, chitotriosidase, hemoglobin and platelets were analyzed in French GD Registry patients receiving imiglucerase/alglucerase as ERT. We used simplified exponential pathophysiological model, with initial concentration, biomarkers amplitude of variation and rate constant of normalization during ERT. Changes in four biomarkers were analyzed separately and then all four together from initiation to discontinuation of ERT, or until the end of follow-up. Several covariates were tested, including age at ERT initiation, splenectomy, sex, genotype (N370S/N370S), and ERT dose.

Results

An exponential model gave a good data fit. The four biomarkers analysis showed that the rate of nomalization was the same for all biomarkers, with a half-life of 0.5 years. Predicted values of biomarkers at ERT’s steady state were 40% and 10% of initial concentrations, for ferritin and chitotriosidase, respectively, and 120% and 200% for hemoglobin and platelets, respectively. We found that 3 covariates had an effect on initial concentration or on amplitude of variation in ferritin, hemoglobin and platelets: women and patients under 15 years of age had lower ferritin and hemoglobin concentrations, and patients under 15 years of age had higher platelet count. Splenectomized patients had higher ferritin concentrations and platelet count and lower amplitude of variation of hemoglobin.

Conclusion

We report the first dynamic model of biomarker changes in GD. It enabled us to estimate that 95% of biomarker response to ERT was achieved in 2 years, but with high inter-patient variability. We also found that with the current treatment, normalization of chitotriosidase and ferritin will occur in about 65% of patients.

Two novel mutations in glucocerebrosidase, C23W and IVS7-1 G>A, identified in Type 1 Gaucher patients heterozygous for N370S

Gaucher disease is an autosomal recessive lysosomal storage disorder resulting from deficient glucocerebrosidase activity. There have been nearly 300 mutations described to date. Novel mutations can potentially provide insight into the biochemical basis of the disease. Two novel mutations are described in two Type 1 Gaucher patients with N370S compound heterozygosity; a point mutation that causes an amino acid substitution at cysteine residue 23 for tryptophan, and a second point mutation within the splicing element at the 3' end of intron 7. Both mutations were identified by PCR amplification and sequence analysis of patient glucocerebrosidase genomic DNA. Restriction fragment length polymorphism analysis was established for both novel mutations for efficient identification in future patients. Past literature suggests that mutations affecting cysteine residues involved in disulfide bridges, as well as mutations affecting splicing patterns of the glucocerebrosidase transcript, are detrimental to enzyme activity. However, compound heterozygosity with N370S, a mild mutation, will lead to a mild phenotype. The cases reported here support these past findings.

Mucopolysaccharidoses and other lysosomal storage diseases

Mucopolysaccharidosis and other lysosomal storage diseases are rare, chronic, and progressive inherited diseases caused by a deficit of lysosomal enzymes. Patients are affected by a wide variety of symptoms. For some lysosomal storage diseases, effective treatments to arrest disease progression, or slow the pathologic process, and increase patient life expectancy are available or being developed. Timely diagnosis is crucial. Rheumatologists, orthopedics, and neurologists are commonly consulted due to unspecific musculoskeletal signs and symptoms. Pain, stiffness, contractures of joints in absence of clinical signs of inflammation, bone pain or abnormalities, osteopenia, osteonecrosis, secondary osteoarthritis or hip dysplasia are the alerting symptoms that should induce suspicion of a lysosomal storage disease.

Gaucher disease: transcriptome analyses using microarray or mRNA sequencing in a Gba1 mutant mouse model treated with velaglucerase alfa or imiglucerase

Gaucher disease type 1, an inherited lysosomal storage disorder, is caused by mutations in GBA1 leading to defective glucocerebrosidase (GCase) function and consequent excess accumulation of glucosylceramide/glucosylsphingosine in visceral organs. Enzyme replacement therapy (ERT) with the biosimilars, imiglucerase (imig) or velaglucerase alfa (vela) improves/reverses the visceral disease. Comparative transcriptomic effects (microarray and mRNA-Seq) of no ERT and ERT (imig or vela) were done with liver, lung, and spleen from mice having Gba1 mutant alleles, termed D409V/null. Disease-related molecular effects, dynamic ranges, and sensitivities were compared between mRNA-Seq and microarrays and their respective analytic tools, i.e. Mixed Model ANOVA (microarray), and DESeq and edgeR (mRNA-Seq). While similar gene expression patterns were observed with both platforms, mRNA-Seq identified more differentially expressed genes (DEGs) (∼3-fold) than the microarrays. Among the three analytic tools, DESeq identified the maximum number of DEGs for all tissues and treatments. DESeq and edgeR comparisons revealed differences in DEGs identified. In 9V/null liver, spleen and lung, post-therapy transcriptomes approximated WT, were partially reverted, and had little change, respectively, and were concordant with the corresponding histological and biochemical findings. DEG overlaps were only 8–20% between mRNA-Seq and microarray, but the biological pathways were similar. Cell growth and proliferation, cell cycle, heme metabolism, and mitochondrial dysfunction were most altered with the Gaucher disease process. Imig and vela differentially affected specific disease pathways. Differential molecular responses were observed in direct transcriptome comparisons from imig- and vela-treated tissues. These results provide cross-validation for the mRNA-Seq and microarray platforms, and show differences between the molecular effects of two highly structurally similar ERT biopharmaceuticals.

Gaucher disease with pathological femoral neck fracture

Fractures of the femoral neck are rare and usually result from serious and high-energy trauma in the skeleton in young adults. Gaucher's disease (GD) is a lysosomal storage disorder that has progressive course and is rarely seen. Research has shown that a pathological femoral neck fracture with GD mostly emerges in childhood. But in adults, there are no reports of pathological femoral neck fractures with GD. We present a unique case of GD with a pathological femoral neck fracture in a 54-year-old woman who did not undergo surgery because of haematological problems including thrombocytopaenia.

Role of platelets in neurodegenerative diseases: a universal pathophysiology

Platelets play an important role in a variety of disorders, namely, cardiovascular, psychosomatic, psychiatric, thrombosis, HIV/AIDS in addition to various neurodegenerative diseases (NDDs). Recent evidence indicates that platelet react to diverse stressors, thereby offering an interesting vantage point for understanding their potential role in contemporary medical research. This review addresses the possible role of platelets as a systemic probe in various NDDs, such as amyotrophic lateral sclerosis, Parkinson's disease, Huntington's disease, Alzheimer's disease, multiple sclerosis, etc. The current review based on published literature, describes a probable link between platelets and pathophysiology of various NDDs. It also discusses how platelets epitomize ultrastructural, morphological, biochemical and molecular changes, highlighting their emerging role as systemic tools in different NDDs.

Abnormal properties of red blood cells suggest a role in the pathophysiology of Gaucher disease

Gaucher disease (GD) is a lysosomal storage disorder caused by glucocerebrosidase deficiency. It is notably characterized by splenomegaly, complex skeletal involvement, ischemic events of the spleen and bones, and the accumulation of Gaucher cells in several organs. We hypothesized that red blood cells (RBCs) might be involved in some features of GD and studied the adhesive and hemorheologic properties of RBCs from GD patients. Hemorheologic analyses revealed enhanced blood viscosity, increased aggregation, and disaggregation threshold of GD RBCs compared with control (CTR) RBCs. GD RBCs also exhibited frequent morphologic abnormalities and lower deformability. Under physiologic flow conditions, GD RBCs adhered more strongly to human microvascular endothelial cells and to laminin than CTR. We showed that Lu/BCAM, the unique erythroid laminin receptor, is overexpressed and highly phosphorylated in GD RBCs, and may play a major role in the adhesion process. The demonstration that GD RBCs have abnormal rheologic and adhesion properties suggests that they may trigger ischemic events in GD, and possibly phagocytosis by macrophages, leading to the appearance of pathogenic Gaucher cells.

Genetic association study of glucocerebrosidase gene L444P mutation in essential tremor and multiple system atrophy in mainland China

The glucocerebrosidase (GBA) gene mutation is emerging as an important risk factor for Parkinson's disease. We previously reported that the GBA gene L444P mutation is an important risk factor for PD in the Chinese population. The prevalence of this mutation in other neurodegenerative diseases and movement disorders remains completely unexplored in mainland China. In the present study, we extended the screening of GBA gene L444P mutation to Chinese patients with essential tremor (ET) and multiple system atrophy (MSA). We searched for the GBA gene L444P mutation in 109 patients with ET, 54 patients with MSA, and 657 controls from mainland China. None of the 109 patients with ET or 54 patients with MSA carried the GBA gene L444P mutation. Among the 657 controls, we found one L444P heterozygote. The difference in mutation frequencies between patients with ET or MSA and the control group was not statistically significant (chi-squared test, p = 1, respectively). The results suggest that the GBA gene L444P mutation may be not responsible for ET in mainland China. Whether the GBA gene L444P mutation modifies the risk for MSA deserves further study in larger samples.

Increased dimerization of alpha-synuclein in erythrocytes in Gaucher disease and aging

Gaucher disease (GD) patients and carriers of glucocerebrosidase mutations are at an increased risk for Parkinson's disease (PD). The presynaptic protein alpha-synuclein (AS) is linked to PD. In the current work we examined biochemical properties of AS in GD patients. We generated membrane-enriched lysates from erythrocytes of 27 patients with GD and 32 age- and sex-matched controls and performed Western immunoblotting with antibodies against AS. Levels of monomeric AS did not differ between GD patients and controls and did not change as a function of age. However, the ratio of dimeric to monomeric AS was significantly increased in GD patients, and showed a significant positive correlation with age. Therefore, two major risk factors for PD, aging and GD status, are associated with an increased AS dimer to monomer ratio in erythrocytes. This ratio needs to be validated in further studies as a potential biomarker for PD risk.

Perinatal gene delivery to the CNS

The relative inaccessibility of the brain compared with other major organs, the highly regulated transfer of molecules across the blood-brain barrier and the limited capacity of neurons to regenerate, make efficient gene delivery to the CNS both challenging and imperative. Perinatal gene delivery to the CNS represents a powerful tool for the investigation of genes in development and disease. However, it may also hold immense therapeutic value for neonatal lethal neurodegenerative diseases for which no treatment is available. This article will focus on the use of perinatal gene delivery as a research tool and the potential it has to develop into a realistic therapy that can be translated to the clinic.

Isolation, characterization, and gene modification of dairy goat mesenchymal stem cells from bone marrow

Bone marrow mesenchymal stem cells (MSCs) are adult pluripotent cells that are considered to be an attractive cell type for therapy models and for nuclear transfer transgenesis. To date, MSCs from various species have been studied, but only a limited amount of information regarding dairy goat MSCs (gMSCs) is available. The objectives of this study were to isolate, induce the multilineage mesenchymal differentiation, and investigate the gene modification efficiency of gMSCs, thereby initiating further research on these cells. The gMSCs isolated from bone marrow grew, attached to plastic with a typical fibroblast-like morphology, and expressed the mesenchymal surface marker CD44, CD29, CD90, and CD166, but not the hematopoietic marker CD45. Furthermore, the gMSCs expressed the transcription factors Oct-4 and Nanog, which have been shown to be critical for stem cell self-renewal and pluripotency. The multilineage differentiation potential of gMSCs was revealed by their ability to undergo adipogenic and osteogenic differentiation when exposed to specific inducing conditions. Transient transduction of gMSCs with a plasmid containing the GFP gene resulted in higher transfection rate compared with fetal fibroblasts (FFs). Furthermore, cell colonies with stable genetic modifications were obtained when gMSCs were transfected with a mammary-specific expression vector containing human lysosomal acid beta-glucosidase gene (hGCase). In conclusion, these results demonstrated that typical mesenchymal stem cells were isolated from dairy goat bone marrow, possessed the characteristics of pluripotent stem cells, and had the potential of specific genetic modifications for gene therapy and producing transgenic goats.

In utero administration of Ad5 and AAV pseudotypes to the fetal brain leads to efficient, widespread and long-term gene expression

The efficient delivery of genetic material to the developing fetal brain represents a powerful research tool and a means to supply therapy in a number of neonatal lethal neurological disorders. In this study, we have delivered vectors based upon adenovirus serotype 5 (Ad5) and adeno-associated virus (AAV) pseudotypes 2/5, 2/8 and 2/9 expressing green fluorescent protein to the E16 fetal mouse brain. One month post injection, widespread caudal to rostral transduction of neural cells was observed. In discrete areas of the brain these vectors produced differential transduction patterns. AAV2/8 and 2/9 produced the most extensive gene delivery and had similar transduction profiles. All AAV pseudotypes preferentially transduced neurons whereas Ad5 transduced both neurons and glial cells. None of the vectors elicited any significant microglia-mediated immune response when compared with control uninjected mice. Whole-body imaging and immunohistological evaluation of brains 9 months post injection revealed long-term expression using these non-integrating vectors. These data will be useful in targeting genetic material to discrete or widespread areas of the fetal brain with the purpose of devising therapies for early neonatal lethal neurodegenerative disease and for studying brain development.

Psychiatric and behavioral manifestations of lysosomal storage disorders

The different lysosomal storage disorders (LSDs) manifest with a wide spectrum of clinical presentations. Most of these disorders are typically diagnosed early in life, due to the severity of the associated phenotypes. However, it is important to appreciate that some of the LSDs present later in adolescence or adulthood. The diverse findings triggering the initial diagnosis, as well as the range of manifestations arising later during the disease course, contribute to the complexity of these issues. Clinical presentations occurring at a more advanced age, especially psychiatric and behavioral manifestations, can be overlooked or misdiagnosed. This review describes different psychiatric and behavioral manifestations encountered in individuals with LSDs, including psychosis, schizophrenia, mood disorders, aggressiveness, early-onset dementia, and conduct disorder. Twelve different disorders are presented, including descriptions of their associated biochemical abnormalities, clinical presentations, pathology, epidemiology, and genetics. In addition, discussions of neurocognitive, behavioral, and psychiatric findings are outlined for each disorder. A greater awareness of these features may help to reduce missed diagnoses, to avoid unnecessary, invasive and expensive testing, and to facilitate an earlier detection of these rare disorders. Earlier diagnosis can enable the implementation of appropriate interventions and improve genetic counseling.

Glucocerebrosidase gene L444P mutation is a risk factor for Parkinson's disease in Chinese population

An association between mutations in the glucocerebrosidase (GBA) gene and Parkinson's disease (PD) has been reported in several populations. We searched for four common GBA mutations (L444P, F213I, R353W, and N370S) in 402 Chinese PD patients and 413 age- and sex-matched controls. In the PD cohort, 11 patients were found carrying a heterozygous GBA mutation and all of them had the L444P mutation. Heterozygous GBA mutations were detected none in controls. The GBA gene L444P mutation was detected at a significantly higher frequency among PD patients (11/402 = 2.74%), when compared with the control group (0/413): P = 0.0007. To evaluate the possible role of the GBA gene L444P mutation in PD in Ashkenazi Jewish and non-Jewish populations, we conducted a meta-analysis on the topic. In the Chinese population, the GBA gene L444P mutation was detected at a significantly higher frequency among PD patients, when compared with the control group: Z = 3.83, P = 0.0001, OR = 8.42, confidence interval = 95%, 2.83-25.06. In the non-Jewish populations, the difference was obviously significant: Z = 5.76, P < 0.00001, OR = 8.82, confidence interval = 95%, 4.21-18.48. The results suggest that the GBA gene L444P mutation appears to be a risk factor for PD in Chinese population.

Gaucher disease: a systematic review and meta-analysis of bone complications and their response to treatment

Type 1 Gaucher disease (GD1) is an inherited lysosomal storage disease, which is often managed by enzyme replacement therapy (ERT). The bone response to ERT is usually slower than visceral and hematological responses. There is uncertainty as to whether an increase in the dosage of ERT has a beneficial effect. The aim of our study was to determine whether or not there is sufficient evidence to make a definitive statement about the effects of ERT and substrate reduction therapy (SRT) on bone marrow infiltration and bone mineral density (BMD) in GD1. We conducted a systematic review of all studies examining the effects of ERT and SRT on bony complications of GD1 published before July 2008. The studies were identified by a computerized search with use of Medline, Embase, The Cochrane Database of Systematic Reviews, The Cochrane Central Register of Controlled Trials (CCTR), and bibliographies of papers subsequently retrieved from the search. Three hundred studies were grouped according to whether they deal with the natural history of GD1 or therapeutic issues, and 17 studies were included in the review. The results from our systematic review suggest that further investigations, such as better analysis of the Gaucher Registry, are needed on the effects of ERT and SRT on bony complications of GD1. Studies on the effects of the newly identified velaglucerase and the plant-derived glucocerebrosidase on bony complications of GD1 are also needed.

Screening for phospholipidosis induced by central nervous drugs: comparing the predictivity of an in vitro assay to high throughput in silico assays

Drug-induced phospholipidosis is a side effect for which drug candidates can be screened in the drug discovery phase. The numerous in silico models that have been developed as a first line of screening are based on the characteristic physicochemical properties of phospholipidosis-inducing drugs, e.g. high logP and pK(b) values. However, applying these models on a predominantly high lipophilic, basic CNS chemistry results in a high false positive rate and consequently in a wrong classification of a large number of valuable drug candidates. Here, we tested 33 CNS-compounds (24 in vivo negative and 9 in vivo positive phospholipidosis-inducers) in our in house developed in vitro phospholipidosis screening assay (Mesens et al., 2009) and compared its predictivity with the outcome of three different, well established in silico prediction models. Our in vitro assay demonstrates an increased specificity of 79% over the in silico models (29%). Moreover, by considering the proposed plasma concentration at the efficacious dose we can show a clear correlation between the in vitro and in vivo occurrence of phospholipidosis, improving the specificity of prediction to 96%. Through its high predictive value, the in vitro low throughput assay is thus preferred above high throughput in silico assays, characterized by a high false positive rate.

Production of dairy goat embryos, by nuclear transfer, transgenic for human acid beta-glucosidase

Expression of recombinant human lysosomal acid beta-glucosidase (hGCase) by a transgenic animal bioreactor, using somatic cell nuclear transfer (SCNT), would decrease the cost of producing this product. The objective was to establish an effective procedure to prepare hGCase transgenic donor cells and nuclear transfer (NT) embryos to produce hGCase protein in the Saanen dairy goat mammary gland. A mammary-specific expression vector for hGCase was constructed and transfected into HC-11 mammary epithelial cells for bioactivity analysis in vitro; mRNA transcripts and hGCase protein were correctly expressed in transfected HC-11 cells. The hGCase gene was then introduced into fetal fibroblasts (from dairy goats) to prepare competent transgenic donor cells. Transgenic fibroblast clones from a single round of transfection were reliably isolated by 96-well cell culture plates and screened with PCR amplification and chromosomal counting (66.8%). Dairy goat cloned embryos were produced from these hGCase fetal cells by SCNT, the hGCase transgene was successfully detected in these embryos, and there were similar rates (P>0.05) of fusion (83.3% vs. 77.8%), cleavage (89.1% vs. 90.9%), and development to the morula/blastocyst stages (36.4% vs. 38.9%) between NT embryos using transgenic fetal fibroblasts and non-transfected control cells. Moreover, 98 well-developed reconstructed embryos derived from transgenic cells were transferred to 16 recipients; pregnancy was confirmed at 40 d in two goats. Therefore, we achieved functional expression of hGCase in mammary gland cells and normal development to Day 40 of cloned embryos carrying the hGCase gene.

Miniaturized tools and devices for bioanalytical applications: an overview

This article presents an overview of various miniaturized devices and technologies developed by our group. Innovative, fast and cheap procedures for the fabrication of laboratory microsystems based on commercially available materials are reported and compared with well-established microfabrication techniques. The modules fabricated and tested in our laboratory can be used independently or they can be set up in different configurations to form functional measurement systems. We also report further applications of the presented modules e.g. disposable poly(dimethylsiloxane) (PDMS) microcuvettes, fibre optic detectors, potentiometric sensors platforms, microreactors and capillary electrophoresis (CE) microchips as well as integrated microsystems e.g. double detection microanalytical systems, devices for studying enzymatic reactions and a microsystem for cell culture and lysis.

Alpha-synuclein-glucocerebrosidase interactions in pharmacological Gaucher models: a biological link between Gaucher disease and parkinsonism

A growing body of experimental and clinical literature indicates an association between Gaucher disease and parkinsonism, raising the possibility that convergent mechanisms may contribute to neurodegeneration in these disorders. The aim of this study was to determine whether there is a relationship between alpha-synuclein (alpha-syn), a key protein in Parkinson's disease pathogenesis, and abnormalities in glucocerebroside (GC) catabolism that lead to the development of Gaucher disease. We inhibited glucocerebrosidase (GCase) with conduritol B epoxide (CBE) in neuroblastoma cells and mice to test whether a biological link exists between GCase activity and alpha-syn. After CBE exposure, enhanced alpha-syn protein was detected in differentiated cells challenged with CBE as compared to vehicle, with no change in alpha-syn mRNA. In the mouse model, after one injection of CBE, elevated nigral alpha-syn levels were also detected. Analyses by Western blot and confocal microscopy revealed that normal alpha-syn distribution was perturbed after CBE exposure with its accumulation apparent within nigral cell bodies as well as astroglia. These findings raise the possibility that alpha-syn may contribute to the cascade of events that promote neuronal dysfunction in Gaucher disease and are the first to implicate this protein as a plausible biological intersection between Gaucher disease and parkinsonism using a pharmacological model.

Giant lymphadenopathy infiltrated by gaucher cells mimicking lymphoma

Gaucher disease (GD) is a lysosomal storage disease characterized by deficiency of beta-glucocerebrosidase, which results in accumulation of glucocerebroside in reticuloendothelial system, bone marrow infiltration, progressive hepatosplenomegaly, and skeletal complications. Herein we report a 5-year-old female with GD receiving enzyme replacement therapy who had giant mesenteric lymphadenopathies.

Assessment of stability, toxicity and immunogenicity of new polymeric nanoreactors for use in enzyme replacement therapy of MNGIE

The lack of a crucial metabolic enzyme can lead to accumulating substrate concentrations in the bloodstream and severe human enzyme deficiency diseases. Mitochondrial Neurogastrointestinal Encephalomyopathy (MNGIE) is such a fatal genetic disorder, caused by a thymidine phosphorylase deficiency. Enzyme replacement therapy is a strategy where the deficient enzyme is administered intravenously in order to decrease the toxic substrate concentrations. Such a therapy is however not very efficient due to the fast elimination of the native enzyme from the circulation. In this study we evaluate the potential of using polymeric enzyme-loaded nanoparticles to improve the delivery of therapeutic enzymes. We constructed new 200-nanometer PMOXA-PDMS-PMOXA polymeric nanoparticles that encapsulate the enzyme thymidine phosphorylase. These particles are permeabilised for substrates and products by the reconstitution of the nucleoside-specific porin Tsx in their polymeric wall. We show that the obtained 'nanoreactors' are enzymatically active and stable in blood serum at 37 degrees C. Moreover, they do not provoke cytotoxicity when incubated with hepatocytes for 4 days, nor do they induce a macrophage-mediated inflammatory response ex vivo and in vivo. All data highlight the potential of such nanoreactors for their application in enzyme replacement therapy of MNGIE.

A novel genotype c.1228C>G/c.1448C-1498C (L371V/Rec-NciI) in a 3-year-old child with type 1 Gaucher disease

Gaucher disease (GD) is an autosomal recessive inborn error of metabolism, resulting from a deficiency of the enzyme glucocerebrosidase, causing an accumulation of the glycolipid glucocerebroside within lysosomes of macrophages in the reticuloendothelial system. Three major clinical forms have been assigned and more than 200 gene mutations have been identified. We herein report a Lebanese boy born with a novel combined mutation L371V/Rec-NciI, who presented with moderate-severe type 1 GD. An overview of the clinical and biomarker improvement following enzyme replacement therapy with imiglucerase is described in a follow-up of 30 months. Imiglucerase seems to be efficacious in decreasing the severity of the disease associated with this mutation. However, a high dose may be required to achieve optimal growth, platelet count, and hemoglobin level.