RESUMO
Mucopolysaccharidosis type IIIA (MPS IIIA) is a rare paediatric lysosomal storage disorder, caused by the progressive accumulation of heparan sulphate, resulting in neurocognitive decline and behavioural abnormalities. Anecdotal reports from paediatricians indicate a more severe neurodegeneration in MPS IIIA patients, following infection, suggesting inflammation as a potential driver of neuropathology. To test this hypothesis, we performed acute studies in which WT and MPS IIIA mice were challenged with the TLR3-dependent viral mimetic poly(I:C). The challenge with an acute high poly(I:C) dose exacerbated systemic and brain cytokine expression, especially IL-1ß in the hippocampus. This was accompanied by an increase in caspase-1 activity within the brain of MPS IIIA mice with concomitant loss of hippocampal GFAP and NeuN expression. Similar levels of cell damage, together with exacerbation of gliosis, were also observed in MPS IIIA mice following low chronic poly(I:C) dosing. While further investigation is warranted to fully understand the extent of IL-1ß involvement in MPS IIIA exacerbated neurodegeneration, our data robustly reinforces our previous findings, indicating IL-1ß as a pivotal catalyst for neuropathological processes in MPS IIIA.
Assuntos
Modelos Animais de Doenças , Mucopolissacaridose III , Poli I-C , Animais , Mucopolissacaridose III/patologia , Mucopolissacaridose III/imunologia , Mucopolissacaridose III/metabolismo , Camundongos , Interleucina-1beta/metabolismo , Doenças Neurodegenerativas/patologia , Doenças Neurodegenerativas/imunologia , Encéfalo/patologia , Encéfalo/metabolismo , Citocinas/metabolismo , Camundongos Endogâmicos C57BL , Hipocampo/patologia , Hipocampo/metabolismoRESUMO
Mucopolysaccharidosis type IIIB (MPS IIIB) is an autosomal inherited disease caused by mutations in gene encoding the lysosomal enzyme N-acetyl-alpha-glucosaminidase (NAGLU). These mutations result in reduced NAGLU activity, preventing it from catalyzing the hydrolysis of the glycosaminoglycan heparan sulfate (HS). There are currently no approved treatments for MPS IIIB. A novel approach in the treatment of lysosomal storage diseases is the use of pharmacological chaperones (PC). In this study, we used a drug repurposing approach to identify and characterize novel potential PCs for NAGLU enzyme. We modeled the interaction of natural and artificial substrates within the active cavity of NAGLU (orthosteric site) and predicted potential allosteric sites. We performed a virtual screening for both the orthosteric and the predicted allosteric site against a curated database of human tested molecules. Considering the binding affinity and predicted blood-brain barrier permeability and gastrointestinal absorption, we selected atovaquone and piperaquine as orthosteric and allosteric PCs. The PCs were evaluated by their capacity to bind NAGLU and the ability to restore the enzymatic activity in human MPS IIIB fibroblasts These results represent novel PCs described for MPS IIIB and demonstrate the potential to develop novel therapeutic alternatives for this and other protein deficiency diseases.
Assuntos
Acetilglucosaminidase , Mucopolissacaridose III , Humanos , Mucopolissacaridose III/tratamento farmacológico , Mucopolissacaridose III/metabolismo , Mucopolissacaridose III/patologia , Acetilglucosaminidase/metabolismo , Acetilglucosaminidase/antagonistas & inibidores , Acetilglucosaminidase/química , Acetilglucosaminidase/genética , Sítio Alostérico/efeitos dos fármacos , Regulação Alostérica/efeitos dos fármacosRESUMO
Mucopolysaccharidosis III type C (MPS IIIC) is an untreatable neuropathic lysosomal storage disease caused by a genetic deficiency of the lysosomal N-acetyltransferase, HGSNAT, catalyzing a transmembrane acetylation of heparan sulfate. HGSNAT is a transmembrane enzyme incapable of free diffusion between the cells or their cross-correction, which limits development of therapies based on enzyme replacement and gene correction. Since our previous work identified neuroinflammation as a hallmark of the CNS pathology in MPS IIIC, we tested whether it can be corrected by replacement of activated brain microglia with neuroprotective macrophages/microglia derived from a heterologous HSPC transplant. Eight-week-old MPS IIIC (HgsnatP304L) mice were transplanted with HSPC from congenic wild type mice after myeloablation with Busulfan and studied using behavior test battery, starting from the age of 6 months. At the age of ~8 months, mice were sacrificed to study pathological changes in the brain, heparan sulfate storage, and other biomarkers of the disease. We found that the treatment corrected several behavior deficits including hyperactivity and reduction in socialization, but not memory decline. It also improved several features of CNS pathology such as microastroglyosis, expression of pro-inflammatory cytokine IL-1ß, and accumulation of misfolded amyloid aggregates in cortical neurons. At the periphery, the treatment delayed development of terminal urinary retention, potentially increasing longevity, and reduced blood levels of heparan sulfate. However, we did not observe correction of lysosomal storage phenotype in neurons and heparan sulfate brain levels. Together, our results demonstrate that neuroinflammation in a neurological lysosomal storage disease, caused by defects in a transmembrane enzyme, can be effectively ameliorated by replacement of microglia bearing the genetic defect with cells from a normal healthy donor. They also suggest that heterologous HSPC transplant, if used together with other methods, such as chaperone therapy or substrate reduction therapy, may constitute an effective combination therapy for MPS IIIC and other disorders with a similar etiology.
Assuntos
Modelos Animais de Doenças , Mucopolissacaridose III , Doenças Neuroinflamatórias , Animais , Mucopolissacaridose III/patologia , Mucopolissacaridose III/terapia , Mucopolissacaridose III/genética , Camundongos , Doenças Neuroinflamatórias/patologia , Doenças Neuroinflamatórias/metabolismo , Lisossomos/metabolismo , Microglia/patologia , Microglia/metabolismo , Camundongos Endogâmicos C57BL , Encéfalo/patologia , Encéfalo/metabolismo , Heparitina Sulfato/metabolismo , Inflamação/patologiaRESUMO
BACKGROUND: Mucopolysaccharidosis (MPS) IIIB, also known as Sanfilippo Syndrome B, is a devastating childhood disease. Unfortunately, there are currently no available treatments for MPS IIIB patients. Yet, animal models of lysosomal storage diseases have been valuable tools in identifying promising avenues of treatment. Enzyme replacement therapy, gene therapy, and bone marrow transplant have all shown efficacy in the MPS IIIB model systems. A ubiquitous finding across rodent models of lysosomal storage diseases is that the best treatment outcomes resulted from intervention prior to symptom onset. Therefore, the aim of the current study was to identify early markers of disease in the MPS IIIB mouse model as well as examine clinically-relevant behavioral domains not yet explored in this model. METHODS: Using the MPS IIIB mouse model, we explored early developmental trajectories of communication and gait, and later social behavior, fear-related startle and conditioning, and visual capabilities. In addition, we examined brain structure and function via magnetic resonance imaging and diffusion tensor imaging. RESULTS: We observed reduced maternal isolation-induced ultrasonic vocalizations in MPS IIIB mice relative to controls, as well as disruption in a number of the spectrotemporal features. MPS IIIB also exhibited disrupted thermoregulation during the first two postnatal weeks without any differences in body weight. The developmental trajectories of gait were largely normal. In early adulthood, we observed intact visual acuity and sociability yet a more submissive phenotype, increased aggressive behavior, and decreased social sniffing relative to controls. MPS IIIB mice showed greater inhibition of startle in response to a pretone with a decrease in overall startle response and reduced cued fear memory. MPS IIIB also weighed significantly more than controls throughout adulthood and showed larger whole brain volumes and normalized regional volumes with intact tissue integrity as measured with magnetic resonance and diffusion tensor imaging, respectively. CONCLUSIONS: Together, these results indicate disease markers are present as early as the first two weeks postnatal in this model. Further, this model recapitulates social, sensory and fear-related clinical features. Our study using a mouse model of MPS IIIB provides essential baseline information that will be useful in future evaluations of potential treatments.
Assuntos
Mucopolissacaridose III , Humanos , Animais , Adulto , Criança , Mucopolissacaridose III/genética , Mucopolissacaridose III/patologia , Imagem de Tensor de Difusão , Encéfalo , Modelos Animais de Doenças , Resultado do TratamentoRESUMO
Mucopolysaccharidosis type IIIA (MPS IIIA) is characterized by neurological and skeletal pathologies caused by reduced activity of the lysosomal hydrolase, sulfamidase, and the subsequent primary accumulation of undegraded heparan sulfate (HS). Respiratory pathology is considered secondary in MPS IIIA and the mechanisms are not well understood. Changes in the amount, metabolism, and function of pulmonary surfactant, the substance that regulates alveolar interfacial surface tension and modulates lung compliance and elastance, have been reported in MPS IIIA mice. Here we investigated changes in lung function in 20-wk-old control and MPS IIIA mice with a closed and open thoracic cage, diaphragm contractile properties, and potential parenchymal remodeling. MPS IIIA mice had increased compliance and airway resistance and reduced tissue damping and elastance compared with control mice. The chest wall impacted lung function as observed by an increase in airway resistance and a decrease in peripheral energy dissipation in the open compared with the closed thoracic cage state in MPS IIIA mice. Diaphragm contractile forces showed a decrease in peak twitch force, maximum specific force, and the force-frequency relationship but no change in muscle fiber cross-sectional area in MPS IIIA mice compared with control mice. Design-based stereology did not reveal any parenchymal remodeling or destruction of alveolar septa in the MPS IIIA mouse lung. In conclusion, the increased storage of HS which leads to biochemical and biophysical changes in pulmonary surfactant also affects lung and diaphragm function, but has no impact on lung or diaphragm structure at this stage of the disease.NEW & NOTEWORTHY Heparan sulfate storage in the lungs of mucopolysaccharidosis type IIIA (MPS IIIA) mice leads to changes in lung function consistent with those of an obstructive lung disease and includes an increase in lung compliance and airway resistance and a decrease in tissue elastance. In addition, diaphragm muscle contractile strength is reduced, potentially further contributing to lung function impairment. However, no changes in parenchymal lung structure were observed in mice at 20 wk of age.
Assuntos
Resistência das Vias Respiratórias , Diafragma , Mucopolissacaridose III , Alvéolos Pulmonares , Animais , Diafragma/fisiopatologia , Diafragma/patologia , Diafragma/metabolismo , Complacência Pulmonar , Camundongos , Alvéolos Pulmonares/patologia , Alvéolos Pulmonares/fisiopatologia , Alvéolos Pulmonares/metabolismo , Mucopolissacaridose III/patologia , Mucopolissacaridose III/fisiopatologia , Mucopolissacaridose III/metabolismo , Mucopolissacaridose III/genética , Contração Muscular/fisiologia , Camundongos Endogâmicos C57BL , Modelos Animais de Doenças , Força Muscular , Pulmão/patologia , Pulmão/fisiopatologia , Pulmão/metabolismo , MasculinoRESUMO
Lysosomes are the terminal end of catabolic pathways in the cell, as well as signaling centers performing important functions such as the recycling of macromolecules, organelles, and nutrient adaptation. The importance of lysosomes in human health is supported by the fact that the deficiency of most lysosomal genes causes monogenic diseases called as a group Lysosomal Storage Diseases (LSDs). A common phenotypic hallmark of LSDs is the expansion of the lysosomal compartment that can be detected by using conventional imaging methods based on immunofluorescence protocols or overexpression of tagged lysosomal proteins. These methods require the alteration of the cellular architecture (i.e., due to fixation methods), can alter the behavior of cells (i.e., by the overexpression of proteins), and require sample preparation and the accurate selection of compatible fluorescent markers in relation to the type of analysis, therefore limiting the possibility of characterizing cellular status with simplicity. Therefore, a quantitative and label-free methodology, such as Quantitative Phase Imaging through Digital Holographic (QPI-DH), for the microscopic imaging of lysosomes in health and disease conditions may represent an important advance to study and effectively diagnose the presence of lysosomal storage in human disease. Here we proof the effectiveness of the QPI-DH method in accomplishing the detection of the lysosomal compartment using mouse embryonic fibroblasts (MEFs) derived from a Mucopolysaccharidosis type III-A (MSP-IIIA) mouse model, and comparing them with wild-type (WT) MEFs. We found that it is possible to identify label-free biomarkers able to supply a first pre-screening of the two populations, thus showing that QPI-DH can be a suitable candidate to surpass fluorescent drawbacks in the detection of lysosomes dysfunction. An appropriate numerical procedure was developed for detecting and evaluate such cellular substructures from in vitro cells cultures. Results reported in this study are encouraging about the further development of the proposed QPI-DH approach for such type of investigations about LSDs.
Assuntos
Lisossomos , Lisossomos/metabolismo , Animais , Camundongos , Fibroblastos/metabolismo , Fibroblastos/patologia , Humanos , Doenças por Armazenamento dos Lisossomos/metabolismo , Doenças por Armazenamento dos Lisossomos/patologia , Doenças por Armazenamento dos Lisossomos/genética , Doenças por Armazenamento dos Lisossomos/diagnóstico , Mucopolissacaridose III/metabolismo , Mucopolissacaridose III/patologia , Mucopolissacaridose III/genética , Imageamento Quantitativo de FaseRESUMO
Mucopolysaccharidosis III (MPSIII, Sanfilippo syndrome) is a devastating lysosomal storage disease that primarily affects the central nervous system. MPSIIIA is caused by loss-of-function mutations in the gene coding for sulfamidase (N-sulfoglucosamine sulfohydrolase/SGSH) resulting in SGSH enzyme deficiency, a buildup of heparin sulfate and subsequent neurodegeneration. There is currently no cure or disease modifying treatment for MPSIIIA. A mouse model for MPSIIIA was characterized in 1999 and later backcrossed onto the C57BL/6 background. In the present study, a novel immune deficient MPSIIIA mouse model (MPSIIIA-TKO) was created by backcrossing the immune competent, C57BL/6 MPSIIIA mouse to an immune deficient mouse model lacking Rag2, CD47 and Il2rg genes. The resulting mouse model has undetectable SGSH activity, exhibits histological changes consistent with MPSIIIA and lacks T cells, B cells and NK cells. This new mouse model has the potential to be extremely useful in testing human cellular therapies in an animal model as it retains the MPSIIIA disease phenotype while tolerating xenotransplantation.
Assuntos
Mucopolissacaridose III , Animais , Humanos , Camundongos , Mucopolissacaridose III/genética , Mucopolissacaridose III/patologia , Camundongos Endogâmicos C57BL , Hidrolases/genética , Fenótipo , Modelos Animais de DoençasRESUMO
Mucopolysaccharidosis IIID (MPS IIID/Sanfilippo syndrome D, OMIM # 252940) is an autosomal recessive lysosomal storage disorder (LSD) and the rarest form of the mucopolysaccharidosis (MPS) III subtypes. It is caused by sequence variations in the gene encoding lysosomal enzyme N-acetyl glucosamine-6-sulphatase (GNS). Deficiency of GNS impairs catabolism of glycosaminoglycans causing accumulation of heparan sulphate within lysosomes of various tissues, which is visualized as membranous cytoplasmic bodies (MCBs) on electron microscopy. The recognition of this ultrastructural feature in a muscle biopsy instigated genetic evaluation for LSD in our case resulting in the detection of a novel pathogenic GNS gene variant. The patient also exhibited intellectual disability since childhood, reduced vision due to pigmentary retinopathy, and behavioral abnormalities without other systemic features of MPS. In this study, we report a patient of Indian origin with MPS IIID based on a novel pathogenic variant c.1078 G>T (p.G360C) in the GNS and the presence of MCBs in muscle biopsy, characterized by several novel findings including the occurrence of pigmentary retinopathy, which extends the clinical spectrum of MPS IIID.
Assuntos
Mucopolissacaridose III , Retinose Pigmentar , Humanos , Criança , Mucopolissacaridose III/genética , Mucopolissacaridose III/diagnóstico , Mucopolissacaridose III/patologia , Glicosaminoglicanos/metabolismo , Genômica , Reconhecimento PsicológicoRESUMO
Sanfilippo syndrome (MPS III) is an autosomal recessive inherited disorder causing dementia in children, following an essentially normal early developmental period. First symptoms typically include delayed language development, hyperactivity and/or insomnia from 2 years of age, followed by unremitting and overt loss of previously acquired skills. There are no approved treatments, and the median age of death is 18 years. Treatments under clinical trial demonstrate therapeutic benefit when applied pre-symptomatically in children diagnosed early through known familial inheritance risk. Newborn screening for Sanfilippo syndrome would enable pre-symptomatic diagnosis and optimal therapeutic benefit, however, many fold more patients with Sanfilippo syndrome are expected to be identified in the population than present with childhood dementia. Therefore, the capacity to stratify which Sanfilippo infants will need treatment in toddlerhood is necessary. While diagnostic methods have been developed, and continue to be refined, currently there are no tools or laboratory-based biomarkers available to provide pre-symptomatic prognosis. There is also a lack of progression and neurocognitive response-to-treatment biomarkers; disease stage and rate of progression are currently determined by age at symptom onset, loss of cerebral grey matter volume by magnetic resonance imaging and developmental quotient score for age. Robust blood-based biomarkers are an urgent unmet need. In this review, we discuss the development of biomarker assays for Sanfilippo based on the neuropathological pathways known to change leading into symptom onset and progression, and their performance as biomarkers in other neurodegenerative diseases. We propose that neural-derived exosomes extracted from blood may provide an ideal liquid biopsy to detect reductions in synaptic protein availability, and mitochondrial function. Furthermore, given the prominent role of neuroinflammation in symptom expression, glial fibrillary acidic protein detection in plasma/serum, alongside measurement of active brain atrophy by neurofilament light chain, warrant increased investigation for prognostic, progression and neurocognitive response-to-treatment biomarker potential in Sanfilippo syndrome and potentially other childhood dementias.
Assuntos
Demência , Mucopolissacaridose III , Criança , Lactente , Recém-Nascido , Humanos , Adolescente , Mucopolissacaridose III/diagnóstico , Mucopolissacaridose III/patologia , Biomarcadores , PrognósticoRESUMO
OBJECTIVE: Mucopolysaccharidosis type IIIA (MPSIIIA) caused by recessive SGSH variants results in sulfamidase deficiency, leading to neurocognitive decline and death. No disease-modifying therapy is available. The AAVance gene therapy trial investigates AAVrh.10 overexpressing human sulfamidase (LYS-SAF302) delivered by intracerebral injection in children with MPSIIIA. Post-treatment MRI monitoring revealed lesions around injection sites. Investigations were initiated in one patient to determine the cause. METHODS: Clinical and MRI details were reviewed. Stereotactic needle biopsies of a lesion were performed; blood and CSF were sampled. All samples were used for viral studies. Immunohistochemistry, electron microscopy, and transcriptome analysis were performed on brain tissue of the patient and various controls. RESULTS: MRI revealed focal lesions around injection sites with onset from 3 months after therapy, progression until 7 months post therapy with subsequent stabilization and some regression. The patient had transient slight neurological signs and is following near-normal development. No evidence of viral or immunological/inflammatory cause was found. Immunohistochemistry showed immature oligodendrocytes and astrocytes, oligodendrocyte apoptosis, strong intracellular and extracellular sulfamidase expression and hardly detectable intracellular or extracellular heparan sulfate. No activation of the unfolded protein response was found. INTERPRETATION: Results suggest that intracerebral gene therapy with local sulfamidase overexpression leads to dysfunction of transduced cells close to injection sites, with extracellular spilling of lysosomal enzymes. This alters extracellular matrix composition, depletes heparan sulfate, impairs astrocyte and oligodendrocyte function, and causes cystic white matter degeneration at the site of highest gene expression. The AAVance trial results will reveal the potential benefit-risk ratio of this therapy.
Assuntos
Encéfalo , Mucopolissacaridose III , Criança , Humanos , Encéfalo/patologia , Terapia Genética/métodos , Mucopolissacaridose III/genética , Mucopolissacaridose III/terapia , Mucopolissacaridose III/patologia , Imuno-Histoquímica , Heparitina Sulfato/metabolismo , Heparitina Sulfato/uso terapêuticoRESUMO
Heparan-α-glucosaminide N-acetyltransferase (HGSNAT) participates in lysosomal degradation of heparan sulfate. Mutations in the gene encoding this enzyme cause mucopolysaccharidosis IIIC (MPS IIIC) or Sanfilippo syndrome type C. MPS IIIC patients exhibit progressive neurodegeneration, leading to dementia and death in early adulthood. Currently there is no approved treatment for MPS IIIC. Incidences of non-syndromic retinitis pigmentosa and early signs of night blindness are reported in some MPS IIIC patients, however the majority of ocular phenotypes are not well characterized. The goal of this study was to investigate retinal degeneration phenotype in the Hgsnat knockout mouse model of MPS IIIC and a cadaveric human MPS IIIC eye. Cone and rod photoreceptors in the eyes of homozygous 6-month-old Hgsnat knockout mice and their wild-type counterparts were analyzed using cone arrestin, S-opsin, M-opsin and rhodopsin antibodies. Histological observation was performed on the eye from a 35-year-old MPS IIIC donor. We observed a nearly 50% reduction in the rod photoreceptors density in the Hgsnat knockout mice compared to the littermate wild-type controls. Cone photoreceptor density was unaltered at this age. Severe retinal degeneration was also observed in the MPS IIIC donor eye. To our knowledge, this is the first report characterizing ocular phenotypes arising from deleterious variants in the Hgsnat gene associated with MPS IIIC clinical phenotype. Our findings indicate retinal manifestations may be present even before behavioral manifestations. Thus, we speculate that ophthalmological evaluations could be used as diagnostic indicators of early disease, progression, and end-point evaluation for future MPS IIIC therapies.
Assuntos
Mucopolissacaridose III , Degeneração Retiniana , Retinose Pigmentar , Animais , Camundongos , Humanos , Adulto , Lactente , Mucopolissacaridose III/genética , Mucopolissacaridose III/diagnóstico , Mucopolissacaridose III/patologia , Degeneração Retiniana/genética , Mutação , Camundongos Knockout , Acetiltransferases/genéticaRESUMO
INTRODUCTION: NAGLU encodes N-acetyl-alpha-glucosaminidase, an enzyme that degrades heparan sulfate. Biallelic NAGLU mutations cause mucopolysaccharidosis IIIB, a severe childhood-onset neurodegenerative disease, while monoallelic mutations are associated to late-onset, dominantly inherited painful sensory neuropathy. However, to date, only one family with a dominant NAGLU-related neuropathy has been described. CASE REPORT: Here we describe a patient with early-onset motor polyneuropathy harboring a novel monoallelic NAGLU mutation. We found reduced NAGLU enzymatic activity thus corroborating the pathogenic role of the new variant. DISCUSSION: Our report represents the second ever described case with dominant NAGLU-related neuropathy and the first case with early-onset motor symptoms. We underlie the importance of a thorough clinical description of this probably underestimated new clinical entity.
Assuntos
Neuropatias Hereditárias Sensoriais e Autônomas , Mucopolissacaridose III , Doenças Neurodegenerativas , Doenças do Sistema Nervoso Periférico , Polineuropatias , Humanos , Criança , Mucopolissacaridose III/diagnóstico , Mucopolissacaridose III/genética , Mucopolissacaridose III/patologia , Polineuropatias/genética , Mutação/genéticaRESUMO
The majority of mucopolysaccharidosis IIIC (MPS IIIC) patients have missense variants causing misfolding of heparan sulfate acetyl-CoA:α-glucosaminide N-acetyltransferase (HGSNAT), which are potentially treatable with pharmacological chaperones. To test this approach, we generated a novel HgsnatP304L mouse model expressing misfolded HGSNAT Pro304Leu variant. HgsnatP304L mice present deficits in short-term and working/spatial memory 2-4 mo earlier than previously described constitutive knockout Hgsnat-Geo mice. HgsnatP304L mice also show augmented severity of neuroimmune response, synaptic deficits, and neuronal storage of misfolded proteins and gangliosides compared with Hgsnat-Geo mice. Expression of misfolded human Pro311Leu HGSNAT protein in cultured hippocampal Hgsnat-Geo neurons further reduced levels of synaptic proteins. Memory deficits and majority of brain pathology were rescued in mice receiving HGSNAT chaperone, glucosamine. Our data for the first time demonstrate dominant-negative effects of misfolded HGSNAT Pro304Leu variant and show that they are treatable by oral administration of glucosamine. This suggests that patients affected with mutations preventing normal folding of the enzyme can benefit from chaperone therapy.
Assuntos
Mucopolissacaridoses , Mucopolissacaridose III , Acetiltransferases , Animais , Glucosamina , Heparitina Sulfato , Humanos , Camundongos , Camundongos Knockout , Mucopolissacaridose III/genética , Mucopolissacaridose III/patologiaRESUMO
Mucopolysaccharidosis type IIIB (MPS IIIB; Sanfilippo syndrome B; OMIM #252920) is a lethal, pediatric, neuropathic, autosomal recessive, and lysosomal storage disease with no approved therapy. Patients are deficient in the activity of N-acetyl-alpha-glucosaminidase (NAGLU; EC 3.2.150), necessary for normal lysosomal degradation of the glycosaminoglycan heparan sulfate (HS). Tralesinidase alfa (TA), a fusion protein comprised of recombinant human NAGLU and a modified human insulin-like growth factor 2, is in development as an enzyme replacement therapy that is administered via intracerebroventricular (ICV) infusion, thus circumventing the blood brain barrier. Previous studies have confirmed ICV infusion results in widespread distribution of TA throughout the brains of mice and nonhuman primates. We assessed the long-term tolerability, pharmacology, and clinical efficacy of TA in a canine model of MPS IIIB over a 20-month study. Long-term administration of TA was well tolerated as compared with administration of vehicle. TA was widely distributed across brain regions, which was confirmed in a follow-up 8-week pharmacokinetic/pharmacodynamic study. MPS IIIB dogs treated for up to 20 months had near-normal levels of HS and nonreducing ends of HS in cerebrospinal fluid and central nervous system (CNS) tissues. TA-treated MPS IIIB dogs performed better on cognitive tests and had improved CNS pathology and decreased cerebellar volume loss relative to vehicle-treated MPS IIIB dogs. These findings demonstrate the ability of TA to prevent or limit the biochemical, pathologic, and cognitive manifestations of canine MPS IIIB disease, thus providing support of its potential long-term tolerability and efficacy in MPS IIIB subjects. SIGNIFICANCE STATEMENT: This work illustrates the efficacy and tolerability of tralesinidase alfa as a potential therapeutic for patients with mucopolysaccharidosis type IIIB (MPS IIIB) by documenting that administration to the central nervous system of MPS IIIB dogs prevents the accumulation of disease-associated glycosaminoglycans in lysosomes, hepatomegaly, cerebellar atrophy, and cognitive decline.
Assuntos
Mucopolissacaridose III , Animais , Encéfalo/metabolismo , Criança , Modelos Animais de Doenças , Cães , Terapia de Reposição de Enzimas , Glicosaminoglicanos/metabolismo , Heparitina Sulfato/líquido cefalorraquidiano , Heparitina Sulfato/uso terapêutico , Humanos , Mucopolissacaridose III/tratamento farmacológico , Mucopolissacaridose III/patologiaRESUMO
PURPOSE: To report two unusual presentations of mucopolysaccharidosis type III (Sanfilippo syndrome) and provide evidence for the cardiac involvement. PATIENTS AND METHODS: We report two siblings with cardiac involvement that were diagnosed in childhood with Sanfilippo A Syndrome (SAS). All patients' diagnosis was confirmed by the excess of heparan sulfate in the urine and the reduction of heparan sulfamidase protein activity. The heart specimens were studied. RESULTS: We report two sibling patients (15-years-old female and 12-years-old female) occurring in sisters both with onset in childhood with no neurological, ophthalmic, hepatic symptoms or coarsening of features as classically described. Both patients underwent bilateral hip arthroplasty in their early 30`s. The older sister had an orthotopic heart transplant because of end-stage heart failure of her cardiomyopathy at the age of 45. She is alive and well. The youngest sister died due to heart failure before a transplantation took place. In the two siblings a thin right ventricular free wall was seen, which triggered the differential diagnosis with arrhythmogenic right ventricular cardiomyopathy or lamin A/C cardiomyopathy. CONCLUSIONS: Early recognition of solitary or mainly cardiac involvement is essential for patients with mucopolysaccharidosis type III (SAS).
Assuntos
Cardiomiopatias , Insuficiência Cardíaca , Mucopolissacaridose III , Adolescente , Feminino , Insuficiência Cardíaca/etiologia , Heparitina Sulfato/metabolismo , Humanos , Lamina Tipo A , Mucopolissacaridose III/complicações , Mucopolissacaridose III/metabolismo , Mucopolissacaridose III/patologiaRESUMO
Mucopolysaccharidosis type IIIB (MPS IIIB or Sanfilippo syndrome type B) is an inherited metabolic disease caused by mutations in the NAGLU gene, encoding α-N-acetylglucosaminidase. Accumulation of undegraded heparan sulfate (one of glycosaminoglycans) arises from deficiency in this enzyme and leads to severe symptoms, especially related to dysfunctions of the central nervous system. Here, we describe a case of two siblings with highly diverse phenotypes, despite carrying the same mutations (c.1189 T > G/c.1211G > A (p.Phe397Val/p.Trp404Ter)) and similar residual activities of α-N-acetylglucosaminidase; the younger patient reveals more severe phenotype; thus, these differences cannot be explained by the age and progression of the disease. Surprisingly, the whole exome sequencing analysis indicated the presence of an additional mutation in one allele of the AUTS2 gene (c.157G > A (p.Ala53Thr)) in the younger patient but not in the older one. Since mutations in this gene are usually dominant and cause delayed development and intellectual disability, it is likely that the observed differences between the MPS IIIB siblings are due to the potentially pathogenic AUTS2 variant, present in one of them. This case confirms also that simultaneous occurrence of two ultra-rare diseases in one patient is actual, despite a low probability of such a combination. Moreover, it is worth noting that apart from the genotype-phenotype correlation and the importance of the residual activity of the deficient enzyme, efficiency of glycosaminoglycan synthesis and global secondary changes in expression of hundreds of genes may considerably modulate the course and severity of MPS, especially Sanfilippo disease.
Assuntos
Mucopolissacaridose III , Alelos , Proteínas do Citoesqueleto/genética , Humanos , Mucopolissacaridose III/diagnóstico , Mucopolissacaridose III/genética , Mucopolissacaridose III/patologia , Mutação , Fenótipo , Irmãos , Fatores de Transcrição/genéticaRESUMO
Sanfilippo D syndrome (mucopolysaccharidosis type IIID) is a lysosomal storage disorder caused by the deficiency of N-acetylglucosamine-6-sulfatase (GNS). A mouse model was generated by constitutive knockout of the Gns gene. We studied affected mice and controls at 12, 24, 36, and 48 weeks of age for neuropathological markers of disease in the somatosensory cortex, primary motor cortex, ventral posterior nuclei of the thalamus, striatum, hippocampus, and lateral and medial entorhinal cortex. We found significantly increased immunostaining for glial fibrillary associated protein (GFAP), CD68 (a marker of activated microglia), and lysosomal-associated membrane protein-1 (LAMP-1) in Sanfilippo D mice compared to controls at 12 weeks of age in all brain regions. Intergroup differences were marked for GFAP and CD68 staining, with levels in Sanfilippo D mice consistently above controls at all age groups. Intergroup differences in LAMP-1 staining were more pronounced in 12- and 24-week age groups compared to 36- and 48-week groups, as control animals showed some LAMP-1 staining at later timepoints in some brain regions. We also evaluated the somatosensory cortex, medial entorhinal cortex, reticular nucleus of the thalamus, medial amygdala, and hippocampal hilus for subunit c of mitochondrial ATP synthase (SCMAS). We found a progressive accumulation of SCMAS in most brain regions of Sanfilippo D mice compared to controls by 24 weeks of age. Cataloging the regional neuropathology of Sanfilippo D mice may aid in understanding the disease pathogenesis and designing preclinical studies to test brain-directed treatments.
Assuntos
Encéfalo/patologia , Mucopolissacaridose III/patologia , Animais , Feminino , Gliose/etiologia , Proteínas de Membrana Lisossomal/análise , Masculino , Camundongos , Microglia/fisiologia , ATPases Mitocondriais Próton-Translocadoras/análise , Mucopolissacaridose III/etiologia , Mucopolissacaridose III/metabolismoRESUMO
INTRODUCTION: Currently, there is no effective therapy for mucopolysaccharidosis IIIA (MPS IIIA). Intravenously-administered enzyme replacement therapies, while effective in other forms of MPS without neurological involvement, have not been successful in patients with MPS IIIA, as they are unable to cross the blood-brain barrier to improve neurological symptoms. We evaluated the long-term safety, tolerability, and clinical outcomes of recombinant human heparan-N-sulfatase (rhHNS) administered intrathecally (IT) in children with MPS IIIA in a phase 1/2 extension study. METHODS: Patients aged ≥3 years with MPS IIIA who had previously completed a phase 1/2 study and received ≥5 of the 6 planned rhHNS infusions via IT administration, were eligible for inclusion. Patients who received 10 mg in the phase 1/2 study had their dose increased to 45 mg. Patients who were treated with 45 mg or 90 mg rhHNS IT in the phase 1/2 study remained on this monthly dose in the extension study. rhHNS was administered via an intrathecal drug delivery device (IDDD). Primary endpoints included the type and severity of adverse events, presence of anti-rhHNS antibodies in the CSF and serum, and changes in laboratory values. Secondary endpoints included standardized neurocognitive assessments and brain magnetic resonance imaging. RESULTS: In the extension study, 12 patients with a mean (SD) age of 9.6 (7.3) years continued treatment with rhHNS IT for a median of 264.4 weeks. Ten of 12 patients completed the extension study. rhHNS IT was generally well-tolerated. All patients experienced at least one treatment-emergent adverse event (TEAE), most being mild or moderate in severity. No serious adverse events (SAEs) were considered related to the study drug, and no deaths occurred. Most SAEs were related to malfunctions of the IDDD. Declines from baseline in Bayley Scales of Infant Development, Third Edition or Kaufman Assessment Battery for Children, Second Edition, Nonverbal Index developmental quotient scores were evident at all rhHNS dosing groups: -17.97%, -18.99%, and -12.12% in the 10/45, 45, and 90 mg groups, respectively, at Month 54. CONCLUSIONS: Overall, rhHNS IT was well tolerated in the extension study. However, rhHNS IT was unable to slow the neurocognitive decline of patients with MPS IIIA. This study was subsequently terminated early because pre-specified efficacy criteria were not met, and the study did not yield clinical proof of concept. (Clinicaltrials.gov Identifier NCT01299727).
Assuntos
Terapia de Reposição de Enzimas/métodos , Mucopolissacaridose III/tratamento farmacológico , Sulfatases/uso terapêutico , Adolescente , Encéfalo/patologia , Criança , Pré-Escolar , Cognição , Feminino , Heparitina Sulfato/líquido cefalorraquidiano , Humanos , Masculino , Mucopolissacaridose III/patologia , Mucopolissacaridose III/psicologia , Proteínas Recombinantes/uso terapêutico , Sulfatases/administração & dosagem , Sulfatases/efeitos adversosRESUMO
Mucopolysaccharidoses (MPSs) are a group of inherited lysosomal storage disorders associated with the deficiency of lysosomal enzymes involved in glycosaminoglycan (GAG) degradation. The resulting cellular accumulation of GAGs is responsible for widespread tissue and organ dysfunctions. The MPS III, caused by mutations in the genes responsible for the degradation of heparan sulfate (HS), includes four subtypes (A, B, C, and D) that present significant neurological manifestations such as progressive cognitive decline and behavioral disorders. The established treatments for the MPS III do not cure the disease but only ameliorate non-neurological clinical symptoms. We previously demonstrated that the natural variant of the hepatocyte growth factor NK1 reduces the lysosomal pathology and reactivates impaired growth factor signaling in fibroblasts from MPS IIIB patients. Here, we show that the recombinant NK1 is effective in rescuing the morphological and functional dysfunctions of lysosomes in a neuronal cellular model of the MPS IIIB. More importantly, NK1 treatment is able to stimulate neuronal differentiation of neuroblastoma SK-NBE cells stable silenced for the NAGLU gene causative of the MPS IIIB. These results provide the basis for the development of a novel approach to possibly correct the neurological phenotypes of the MPS IIIB as well as of other MPSs characterized by the accumulation of HS and progressive neurodegeneration.
Assuntos
Heparitina Sulfato/metabolismo , Modelos Biológicos , Mucopolissacaridose III/metabolismo , Neurônios/metabolismo , Sítios de Ligação , Diferenciação Celular , Humanos , Lisossomos/metabolismo , Mucopolissacaridose III/patologia , Neurônios/patologia , Células Tumorais CultivadasRESUMO
Lysosomal storage disorders characterized by altered metabolism of heparan sulfate, including Mucopolysaccharidosis (MPS) III and MPS-II, exhibit lysosomal dysfunctions leading to neurodegeneration and dementia in children. In lysosomal storage disorders, dementia is preceded by severe and therapy-resistant autistic-like symptoms of unknown cause. Using mouse and cellular models of MPS-IIIA, we discovered that autistic-like behaviours are due to increased proliferation of mesencephalic dopamine neurons originating during embryogenesis, which is not due to lysosomal dysfunction, but to altered HS function. Hyperdopaminergia and autistic-like behaviours are corrected by the dopamine D1-like receptor antagonist SCH-23390, providing a potential alternative strategy to the D2-like antagonist haloperidol that has only minimal therapeutic effects in MPS-IIIA. These findings identify embryonic dopaminergic neurodevelopmental defects due to altered function of HS leading to autistic-like behaviours in MPS-II and MPS-IIIA and support evidence showing that altered HS-related gene function is causative of autism.