Identification of metabolic pathways and key genes associated with atypical parkinsonism using a systems biology approach.

Atypical parkinsonism (AP) is a group of complex neurodegenerative disorders with marked clinical and pathophysiological heterogeneity. The use of systems biology tools may contribute to the characterization of hub-bottleneck genes, and the identification of its biological pathways to broaden the understanding of the bases of these disorders. A systematic search was performed on the DisGeNET database, which integrates data from expert curated repositories, GWAS catalogues, animal models and the scientific literature. The tools STRING 11.0 and Cytoscape 3.8.2 were used for analysis of protein-protein interaction (PPI) network. The PPI network topography analyses were performed using the CytoHubba 0.1 plugin for Cytoscape. The hub and bottleneck genes were inserted into 4 different sets on the InteractiveVenn. Additional functional enrichment analyses were performed to identify Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways and gene ontology for a described set of genes. The systematic search in the DisGeNET database identified 485 genes involved with Atypical Parkinsonism. Superimposing these genes, we detected a total of 31 hub-bottleneck genes. Moreover, our functional enrichment analyses demonstrated the involvement of these hub-bottleneck genes in 3 major KEGG pathways. We identified 31 highly interconnected hub-bottleneck genes through a systems biology approach, which may play a key role in the pathogenesis of atypical parkinsonism. The functional enrichment analyses showed that these genes are involved in several biological processes and pathways, such as the glial cell development, glial cell activation and cognition, pathways were related to Alzheimer disease and Parkinson disease. As a hypothesis, we highlight as possible key genes for AP the MAPT (microtubule associated protein tau), APOE (apolipoprotein E), SNCA (synuclein alpha) and APP (amyloid beta precursor protein) genes.

Copy number variations in SPAST and ATL1 are rare among Brazilians.

Copy number variations (CNV) may represent a significant proportion of SPG4 and SPG3A diagnosis, the most frequent autosomal dominant subtypes of hereditary spastic paraplegias (HSP). We aimed to assess the frequency of CNVs in SPAST and ATL1 and to update the molecular epidemiology of HSP families in southern Brazil. A cohort study that included 95 Brazilian index cases with clinical suspicion of HSP was conducted between April 2011 and September 2022. Multiplex Ligation Dependent Probe Amplification (MLPA) was performed in 41 cases without defined diagnosis by different massive parallel sequencing techniques (MPS). Diagnosis was obtained in 57/95 (60%) index cases, 15/57 (26.3%) being SPG4. Most frequent autosomal recessive HSP subtypes were SPG7 followed by SPG11, SPG76 and cerebrotendinous xanthomatosis. No CNVs in SPAST and ATL1 were found. Copy number variations are rare among SPG4 and SPG3A families in Brazil. Considering the possibility of CNVs detection by specific algorithms with MPS data, we consider that this is likely the most cost-effective approach to investigate CNVs in these genes in low-risk populations, with MLPA being reserved as an orthogonal confirmatory test.

Cytokine profiling in patients with hepatic glycogen storage disease: Are there clues for unsolved aspects?

INTRODUCTION: Hepatic Glycogen Storage Diseases (GSD) are rare genetic disorders in which the gluconeogenesis pathway is impaired. Cytokines control virtually every aspect of physiology and may help to elucidate some unsolved questions about phenotypes presented by GSD patients. METHODS: This was an exploratory study in which 27 GSD patients on treatment (Ia = 16, Ib = 06, III = 02, IXα = 03) and 24 healthy age- and sex-matched subjects had plasma samples tested for a panel of 20 cytokines (G-CSF,GM-CSF, IL-1α,IL-1ß, IL-4, IL-6, IL-8, IL-10, IL-13, IL-17A, GRO, IP-10/CXCL10, MCP-1/CCL2, MIP-1α/CCL3, MIP-1ß/CCL4, MDC/CCL22, IFN-γ, TNF-α, TNF-ß, VEGF) through a multiplex kit and analyzed in comparison to controls and among patients, regarding to clinical features as anemia, hepatic adenocarcinoma and triglyceride levels. RESULTS: Patients (GSD-Ia/III/IX) presented reduced levels of IL-4 (p = 0.040), MIP-1α/CCL3 (p = 0.003), MDC/CCL22 (p < 0.001), TNF-ß (p = 0.045) and VEGF (p = 0.043) compared to controls. When different types of GSD were compared, G-CSF was higher in GSD-Ib than -Ia (p < 0.001) and than -III/IX (p = 0.033) patients; IL-10 was higher in GSD-Ib than in GSD-Ia patients (p = 0.019); and GSD-III/IX patients had increased levels of IP-10/CXCL10 than GSD-Ib patients (p = 0.019). When GSD-I patients were gathered into the same group and compared with GSD-III/IX patients, IP10/CXCL10 and MCP-1 were higher in the latter group (p = 0.005 and p = 0.013, respectively). GSD-I patients with anemia presented higher levels of IL-4 and MIP-1α in comparison with patients who had not. Triglyceride level was correlated with neutrophil count and MDC levels on GSD-Ia patients without HCA. CONCLUSION: Altogether, altered levels of cytokines in GSD-I patients reflect an imbalance in immunoregulation process. This study also indicates that neutrophils and some cytokines are affected by triglyceride levels, and future studies on the theme should consider this variable.

Genome Editing Tools for Lysosomal Storage Disorders.

Genome editing has multiple applications in the biomedical field. They can be used to modify genomes at specific locations, being able to either delete, reduce, or even enhance gene transcription and protein expression. Here, we summarize applications of genome editing used in the field of lysosomal disorders. We focus on the development of cell lines for study of disease pathogenesis, drug discovery, and pathogenicity of specific variants. Furthermore, we highlight the main studies that use gene editing as a gene therapy platform for these disorders, both in preclinical and clinical studies. We conclude that gene editing has been able to change quickly the scenario of these disorders, allowing the development of new therapies and improving the knowledge on disease pathogenesis. Should they confirm their hype, the first gene editing-based products for lysosomal disorders could be available in the next years.

Diagnostic yield of multi-gene panel for muscular dystrophies and other hereditary myopathies.

Genetic testing is being considered the first-step in the investigation of hereditary myopathies. However, the performance of the different testing approaches is little known. The aims of the present study were to evaluate the diagnostic yield of a next-generation sequencing panel comprising 39 genes as the first-tier test for genetic myopathies diagnosis and to characterize clinical and molecular findings of families from southern Brazil. Fifty-one consecutive index cases with clinical suspicion of genetic myopathies were recruited from October 2014 to March 2018 in a cross-sectional study. The overall diagnostic yield of the next-generation sequencing panel was 52.9%, increasing to 60.8% when including cases with candidate variants. Multi-gene panel solved the diagnosis of 12/25 (48%) probands with limb-girdle muscular dystrophies, of 7/14 (50%) with congenital muscular diseases, and of 7/10 (70%) with muscular dystrophy with prominent joint contractures. The most frequent diagnosis for limb-girdle muscular dystrophies were LGMD2A/LGMD-R1-calpain3-related and LGMD2B/LGMD-R2-dysferlin-related; for congenital muscular diseases, RYR1-related-disorders; and for muscular dystrophy with prominent joint contractures, Emery-Dreifuss-muscular-dystrophy-type-1 and COL6A1-related-disorders. In summary, the customized next-generation sequencing panel when applied in the initial investigation of genetic myopathies results in high diagnostic yield, likely reducing patient's diagnostic odyssey and providing important information for genetic counseling and participation in disease-specific clinical trials.

Risk factors associated with the development of oral mucositis in pediatric oncology patients: Systematic review and meta-analysis.

OBJECTIVES: Oral mucositis (OM) is an acute toxicity related to cancer treatment. This systematic review aimed to identify potential risk factors associated with the development of OM in pediatric cancer patients. METHODS: A search was performed in four electronic databases to identify studies that analyzed risk factors for OM in pediatric cancer patients. RESULTS: Nineteen articles were included. The incidence of OM ranged from 20% to 80.4%. Chemotherapeutic agents were potential risk factors for OM in eight (42%) studies. Hematological, hepatic, and renal parameters were also considered in eight (42%) studies, while specific individual factors were reported in five (26.3%) studies. Baseline disease, oral microbiota, genetic profile, and biomarkers were reported in four (21.5%) studies each. Meta-analysis showed that groups submitted to high-risk chemotherapy for OM had a 2.79-fold increased risk of OM. CONCLUSIONS: Identifying risk factors for OM is essential in order to allow individualized and early prevention treatment.

Elevated holo-transcobalamin in Gaucher disease type II: A case report.

Gaucher disease (GD), one of the most common lysosomal disorders, is caused by deficiency of ß-glucocerebrosidase. Based on the presence and severity of neurological complications, GD is classified into types I, II (the most severe form), and III. Abnormalities in systemic markers of vitamin B12 (B12 ) metabolism have been reported in GD type I patients, suggesting a higher prevalence of B12 deficiency in these patients. A 2-month-old male with GD type II was admitted to the hospital presenting jaundice, hepatosplenomegaly, and ichthyosis. At admission, cholestasis and ascites, abnormal liver function enzymes, prolonged prothrombin time, and high levels of B12 were confirmed. Analysis of biomarkers of B12 status revealed elevated B12 and holo-transcobalamin (holo-TC) levels. The B12 profile found in our patient is the opposite to what is described for GD type I patients. Holo-TC may increase in inflammatory states or due to liver diseases. In GD, the accumulation of glucocerebroside may be a trigger that initiates a systemic inflammatory reaction, characterized by macrophage activation. We suggest higher levels of holo-TC could be associated with a more severe (neuronopathic) GD, and be a biomarker of GD type II.

Assessment of cellular cobalamin metabolism in Gaucher disease.

BACKGROUND: Gaucher disease (GD) is a lysosomal disorder caused by biallelic pathogenic mutations in the GBA1 gene that encodes beta-glucosidase (GCase), and more rarely, by a deficiency in the GCase activator, saposin C. Clinically, GD manifests with heterogeneous multiorgan involvement mainly affecting hematological, hepatic and neurological axes. This disorder is divided into three types, based on the absence (type I) or presence and severity (types II and III) of involvement of the central nervous system. At the cellular level, deficiency of GBA1 disturbs lysosomal storage with buildup of glucocerebroside. The consequences of disturbed lysosomal metabolism on biochemical pathways that require lysosomal processing are unknown. Abnormal systemic markers of cobalamin (Cbl, B12) metabolism have been reported in patients with GD, suggesting impairments in lysosomal handling of Cbl or in its downstream utilization events. METHODS: Cultured skin fibroblasts from control humans (n = 3), from patients with GD types I (n = 1), II (n = 1) and III (n = 1) and an asymptomatic carrier of GD were examined for their GCase enzymatic activity and lysosomal compartment intactness. Control human and GD fibroblasts were cultured in growth medium with and without 500 nM hydroxocobalamin supplementation. Cellular cobalamin status was examined via determination of metabolomic markers in cell lysate (intracellular) and conditioned culture medium (extracellular). The presence of transcobalamin (TC) in whole cell lysates was examined by Western blot. RESULTS: Cultured skin fibroblasts from GD patients exhibited reduced GCase activity compared to healthy individuals and an asymptomatic carrier of GD, demonstrating a preserved disease phenotype in this cell type. The concentrations of total homocysteine (tHcy), methylmalonic acid (MMA), cysteine (Cys) and methionine (Met) in GD cells were comparable to control levels, except in one patient with GD III. The response of these metabolomic markers to supplementation with hydroxocobalamin (HOCbl) yielded variable results. The content of transcobalamin in whole cell lysates was comparable in control human and GD patients. CONCLUSIONS: Our results indicate that cobalamin transport and cellular processing pathways are overall protected from lysosomal storage damage in GD fibroblasts. Extending these studies to hepatocytes, macrophages and plasma will shed light on cell- and compartment-specific vitamin B12 metabolism in Gaucher disease.

Metabarcoding reveals that a non-nutritive sweetener and sucrose yield similar gut microbiota patterns in Wistar rats.

The effects of non-nutritive sweeteners (NNS) on the gut microbiota are an area of increasing research interest due to their potential influence on weight gain, insulin resistance, and inflammation. Studies have shown that mice and rats fed saccharin develop weight gain and metabolic alterations, possibly related to changes in gut microbiota. Here, we hypothesized that chronic exposure to a commercial NNS would change the gut microbiota composition in Wistar rats when compared to sucrose exposure. To test this hypothesis, Wistar rats were fed either NNS- or sucrose-supplemented yogurt for 17 weeks alongside standard chow (ad libitum). The gut microbiome was assessed by 16S rDNA deep sequencing. Assembly and quantification were conducted using the Brazilian Microbiome Project pipeline for Ion Torrent data with modifications. Statistical analyses were performed in the R software environment. We found that chronic feeding of a commercial NNS-sweetened yogurt to Wistar rats, within the recommended dose range, did not significantly modify gut microbiota composition in comparison to sucrose-sweetened yogurt. Our findings do not support the hypothesis that moderate exposure to NNS is associated with changes in gut microbiota pattern compared to sucrose, at least in this experimental model.

Humoral immune response in adult Brazilian patients with Mucolipidosis III gamma.

Mucolipidosis II and III (ML II and III) alpha/beta and ML III gamma are lysosomal diseases caused by GlcNAc-1-phosphotransferase deficiency. Previous data indicate that MLII patients have functionally impaired immune system that contributes to predisposition to infections.We evaluated the immunological phenotype of three Brazilian patients with ML III gamma. Our data suggest that the residual activity of GlcNAc-1-phosphotransferase in patients with ML III gamma is enough to allow the targeting of the lysosomal enzymes required for B-cell functions maintenance.

Determining the pathogenicity of CFTR missense variants: Multiple comparisons of in silico predictors and variant annotation databases.

Pathogenic variants in the Cystic Fibrosis Transmembrane Conductance Regulator gene (CFTR) are responsible for cystic fibrosis (CF), the commonest monogenic autosomal recessive disease, and CFTR-related disorders in infants and youth. Diagnosis of such diseases relies on clinical, functional, and molecular studies. To date, over 2,000 variants have been described on CFTR (~40% missense). Since few of them have confirmed pathogenicity, in silico analysis could help molecular diagnosis and genetic counseling. Here, the pathogenicity of 779 CFTR missense variants was predicted by consensus predictor PredictSNP and compared to annotations on CFTR2 and ClinVar. Sensitivity and specificity analysis was divided into modeling and validation phases using just variants annotated on CFTR2 and/or ClinVar that were not in the validation datasets of the analyzed predictors. After validation phase, MAPP and PhDSNP achieved maximum specificity but low sensitivity. Otherwise, SNAP had maximum sensitivity but null specificity. PredictSNP, PolyPhen-1, PolyPhen-2, SIFT, nsSNPAnalyzer had either low sensitivity or specificity, or both. Results showed that most predictors were not reliable when analyzing CFTR missense variants, ratifying the importance of clinical information when asserting the pathogenicity of CFTR missense variants. Our results should contribute to clarify decision making when classifying the pathogenicity of CFTR missense variants.

Sensitivity, advantages, limitations, and clinical utility of targeted next-generation sequencing panels for the diagnosis of selected lysosomal storage disorders.

Lysosomal storage disorders (LSDs) constitute a heterogeneous group of approximately 50 genetic disorders. LSDs diagnosis is challenging due to variability in phenotype penetrance, similar clinical manifestations, and a high allelic heterogeneity. A powerful tool for the diagnosis of the disease could reduce the "diagnostic odyssey" for affected families, leading to an appropriate genetic counseling and a better outcome for current therapies, since enzyme replacement therapies have been approved in Brazil for Gaucher, Fabry, and Pompe diseases, and are under development for Niemann-Pick Type B. However, application of next-generation sequencing (NGS) technology in the clinical diagnostic setting requires a previous validation phase. Here, we assessed the application of this technology as a fast, accurate, and cost-effective method to determine genetic diagnosis in selected LSDs. We have designed two panels for testing simultaneously 11 genes known to harbor casual mutations of LSDs. A cohort of 58 patients was used to validate those two panels, and the clinical utility of these gene panels was tested in four novel cases. We report the assessment of a NGS approach as a new tool in the diagnosis of LSDs in our service.

Phenotype-oriented NGS panels for mucopolysaccharidoses: Validation and potential use in the diagnostic flowchart.

Mucopolysaccharidosis (MPS) are a group of rare genetic disorders caused by deficiency in the activity of specific lysosomal enzymes required for the degradation of glycosaminoglycans (GAGs). A defect in the activity of these enzymes will result in the abnormal accumulation of GAGs inside the lysosomes of most cells, inducing progressive cellular damage and multiple organ failure. DNA samples from 70 patients with biochemical diagnosis of different MPSs genotypes confirmed by Sanger sequencing were used to evaluate a Next Generation Sequencing (NGS) protocol. Eleven genes related to MPSs were divided into three different panels according to the clinical phenotype. This strategy led to the identification of several pathogenic mutations distributed across all exons of MPSs-related genes. We were able to identify 96% of all gene variants previously identified by Sanger sequencing, showing high sensitivity in detecting different types of mutations. Furthermore, new variants were not identified, representing 100% specificity of the NGS protocol. The use of this NGS approach for genotype identification in MPSs is an attractive option for diagnosis of patients. In addition, the MPS diagnosis workflow could be divided in a two-tier approach: NGS as a first-tier followed by biochemical confirmation as a second-tier.

Use of a multiplex ligation-dependent probe amplification method for the detection of deletions/duplications in the GBA1 gene in Gaucher disease patients.

Gaucher disease (GD) is caused by the deficient activity of ß-glucocerebrosidase due to pathogenic mutations in the GBA1. This gene has a pseudogene (GBAP) with 96% of sequence homology. Recombination (Rec) events in the GBA1 seem to be facilitated by an increased degree of homology and proximity to the GBAP. The objectives of this study were to validate the P338-X1 GBA kit (MRC-Holland) for Multiplex Ligation-dependent Probe Amplification (MLPA) and to detect larger deletions/duplications present in GBA1 in GD patients from Brazil. Thirty-three unrelated Brazilian GD patients, previously genotyped by the Sanger method (both pathogenic alleles identified=29 patients, only one allele identified=3 patients, no pathogenic alleles identified=1 patient), were evaluated by the MLPA assay. MLPA was compatible with the previous results obtained by Sanger sequencing and identified an additional allele (a heterozygous deletion in intron 7 in one patient with only one mutation identified by Sanger). Our data suggest that, although larger deletions/duplications do not appear to be frequent in GD, the P338-X1 GBA kit for MLPA appears to be a good method for GBA1 analysis. Additional investigations should be performed in order to characterize the remaining four uncharacterized alleles of our sample.

Tyrosine receptor kinase B gene variants (NTRK2 variants) are associated with depressive disorders in temporal lobe epilepsy.

RATIONALE: Psychiatric comorbidities are highly prevalent in epilepsy, adding an important burden to the disease and profoundly affecting the quality of life of these individuals. Patients with temporal lobe epilepsy (TLE) are especially at risk to develop depression and several lines of evidence suggest that the association of depression with epilepsy might be related to common biological substrates. In this study, we test whether NTRK2 allele variants are associated with mood disorders or depressive disorders in patients with TLE. METHODS: An association study of 163 patients with TLE. The NTRK2 variants studied were rs1867283, rs10868235, rs1147198, rs11140800, rs1187286, rs2289656, rs1624327, rs1443445, rs3780645, and rs2378672. All patients were submitted to the Structured Clinical Interview for DSM-IV (SCID) and epilepsy patients with mood disorders or depressive disorders were compared to epilepsy patients without mood disorders or depressive disorders. RESULTS: In our TLE cohort, 76 patients (46.6%) showed mood disorders. After logistic regression, independent risk factors for mood disorders in TLE were female sex, presence of concomitant anxiety disorders, and genetic variations in rs1867283 and rs10868235 NTRK2 variants. Depressive disorders accounted for this results and independent variables associated with depressive disorders in TLE were female sex (OR=2.59; 95%CI=1.15-5.82; p=0.021), presence of concomitant anxiety disorders (OR=3.72; 95%CI=1.71-8.06; p=0.001) or psychotic disorders (OR=3.86; 95%CI=1.12-13.25; p=0.032), A/A genotype in the rs1867283 NTRK2 gene (OR=3.06; 95%CI=1.25-7.50; p=0.015) and C/C genotype in the rs10868235 NTRK2 gene (OR=3.54; 1.55-8.08; p=0.003). Similarly, these genotypes also remained independently and significantly associated with depressive disorders when patients with depressive disorders were compared to TLE patients without any psychiatric comorbidity. CONCLUSION: In the present study, female sex, presence of concomitant anxiety or psychotic disorders, and specific allelic variations in the NTRK2 gene were independently associated with mood disorders or depressive disorders in TLE. If our results were confirmed, variants in the NTRK2 gene could be considered as risk factors or biomarkers for depressive disorders in patients with TLE.

Glycosylation is crucial for a proper catalytic site organization in human glucocerebrosidase.

Gaucher disease, an autosomal recessive disorder, is caused by a deficiency of glucocerebrosidase (GCase) enzyme, a peripheral membrane-associated glycoprotein that hydrolyses glucosylceramide in lysosomes. Glycosylation is essential for the development of a catalytically active enzyme, specifically in the first site, located at Asn19. However, both the molecular basis of the relevance of N-glycosylation over GCase activity and the effects of glycosylation over its structure and dynamics are still not fully understood. Thus, the present work evaluated GCase enzyme in increasing glycosylation content using triplicate unbiased molecular dynamics simulations. Accordingly, the N-linked glycan chains caused local conformational stabilization effects over the protein, as well as in regions flanking the enzyme catalytic dyad. In the case of the Asn19-linked glycan, it also occurred around region 438-444, where one of the most prevalent GCase mutations is found. Markedly, an increasing catalytic dyad organization was related to increasing glycosylation contents, offering the first atomic-level explanation for the experimental observation that GCase activity is controlled by glycosylation, especially at Asn19.

The prognostic value of the serum ferritin in a southern Brazilian cohort of patients with Gaucher disease.

The clinical utility of serum ferritin as a biomarker of disease severity and prognosis in Gaucher disease (GD) is still debated. Here, we aimed to evaluate ferritin and its relation to clinicolaboratory parameters of GD patients seen at the Reference Center for Gaucher Disease of Rio Grande do Sul, Brazil, so as to gather evidence on the utility of ferritin as a biomarker of this condition. A retrospective chart review was performed collecting pre-and posttreatment data from GD patients. Eighteen patients with ferritin levels available before and after treatment were included in the study. Nine of these participants were males, and seventeen had type I GD. All patients were given either enzyme replacement (n = 16) or substrate reduction therapy (n = 2), and ferritin was found to decrease from 756 [318-1441] ng/mL at baseline to 521 [227-626] ng/mL (p=0.025) after 28.8 month soft treatment. Serum ferritin levels did not correlate with measures of disease severity, but showed an association with age at onset of treatment (ρ= 0.880; n = 18; p < 0.001). In conclusion, although serum ferritin did not correlate with disease severity, after a median 28.8 months of treatment, clinical outcomes had clearly improved, and ferritin levels had decreased.

Glucocerebrosidase is shaking up the synucleinopathies.

The lysosomal enzyme glucocerebrosidase, encoded by the glucocerebrosidase gene, is involved in the breakdown of glucocerebroside into glucose and ceramide. Lysosomal build-up of the substrate glucocerebroside occurs in cells of the reticulo-endothelial system in patients with Gaucher disease, a rare lysosomal storage disorder caused by the recessively inherited deficiency of glucocerebrosidase. Gaucher disease has a broad clinical phenotypic spectrum, divided into non-neuronopathic and neuronopathic forms. Like many monogenic diseases, the correlation between clinical manifestations and molecular genotype is not straightforward. There is now a well-established clinical association between mutations in the glucocerebrosidase gene and the development of more prevalent multifactorial disorders including Parkinson's disease and other synucleinopathies. In this review we discuss recent studies advancing our understanding of the cellular relationship between glucocerebrosidase and α-synuclein, the potential impact of established and emerging therapeutics for Gaucher disease for the treatment of the synucleinopathies, and the role of lysosomal pathways in the pathogenesis of these neurodegenerative disorders.

Identification of miRNAs that modulate glucocerebrosidase activity in Gaucher disease cells.

Gaucher disease is an autosomal recessive disorder caused by deficiency of the enzyme glucocerebrosidase. Although it is a monogenic disease, there is vast phenotypic heterogeneity, even among patients with the same genotype. MicroRNAs (miRNAs) are small non-coding RNAs involved in many biological processes and diseases. To determine whether miRNAs can affect glucocerebrosidase activity, we performed a screen of 875 different miRNA mimics. The screen was performed using Gaucher fibroblasts, and glucocerebrosidase activity was used as the initial outcome parameter. We found several miRNAs that either up- or down-regulated glucocerebrosidase activity. In follow-up assays, we confirmed that one specific miRNA (miR-127-5p) down-regulated both glucocerebrosidase activity and protein levels by down-regulation of LIMP-2, the receptor involved in proper trafficking of glucocerebrosidase from the endoplasmic reticulum to the lysosome. A conditioned media assay demonstrated that cells treated with this miRNA secreted glucocerebrosidase into the extracellular environment, supporting impaired LIMP-2 function. Two other miRNAs, miR-16-5p and miR-195-5p, were found to up-regulate glucocerebrosidase activity by greater than 40% and to enhance expression and protein levels of the enzyme. In conclusion, we show that miRNAs can alter glucocerebrosidase activity in patient cells, indicating that miRNAs can potentially act as modifiers in Gaucher disease.