RESUMO
Mucopolysaccharidosis type I is a rare autosomal recessive genetic disease caused by deficient activity of α-L-iduronidase. As a consequence of low or absent activity of this enzyme, glycosaminoglycans accumulate in the lysosomal compartments of multiple cell types throughout the body. Mucopolysaccharidosis type I has been classified into 3 clinical subtypes, ranging from a severe Hurler form to the more attenuated Hurler-Scheie and Scheie phenotypes. Over 200 gene variants causing the various forms of mucopolysaccharidosis type I have been reported. DNA isolated from dried blood spot was used to sequencing of all exons of the IDUA gene from a patient with a clinical phenotype of severe mucopolysaccharidosis type I syndrome. Enzyme activity of α-L-iduronidase was quantified by fluorimetric assay. Additionally, a molecular dynamics simulation approach was used to determine the effect of the Ser633Trp mutation on the structure and dynamics of the α-L-iduronidase. The DNA sequencing analysis and enzymatic activity shows a c.1898C>G mutation associated a patient with a homozygous state and α-L-iduronidase activity of 0.24 µmol/L/h, respectively. The molecular dynamics simulation analysis shows that the p.Ser633Trp mutation on the α-L-iduronidase affect significant the temporal and spatial properties of the different structural loops, the N-glycan attached to Asn372 and amino acid residues around the catalytic site of this enzyme. Low enzymatic activity observed for p.Ser633Trp variant of the α-L-iduronidase seems to lead to severe mucopolysaccharidosis type I phenotype, possibly associated with a perturbation of the structural dynamics in regions of the enzyme close to the active site.
Assuntos
Anormalidades Múltiplas/genética , Dermatan Sulfato/química , Heparitina Sulfato/química , Iduronidase/química , Mucopolissacaridose I/genética , Mutação Puntual , Anormalidades Múltiplas/enzimologia , Anormalidades Múltiplas/patologia , Anormalidades Múltiplas/terapia , Domínio Catalítico , Cristalografia por Raios X , Dermatan Sulfato/metabolismo , Terapia de Reposição de Enzimas/métodos , Expressão Gênica , Heparitina Sulfato/metabolismo , Humanos , Iduronidase/genética , Iduronidase/metabolismo , Lactente , Masculino , Simulação de Dinâmica Molecular , Mucopolissacaridose I/enzimologia , Mucopolissacaridose I/patologia , Mucopolissacaridose I/terapia , Análise de Componente Principal , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , Especificidade por SubstratoRESUMO
Mucopolysaccharidosis type I (MPS I) is caused by a deficiency of α-L-iduronidase (IDUA), resulting in accumulation of glycosaminoglycans (GAG) in lysosomes. Microencapsulation of recombinant cells is a promising gene/cell therapy approach that could overcome the limitations of the current available treatments. In the present study we produced alginate-poly-L-lysine-alginate (APA) microcapsules containing recombinant cells overexpressing IDUA, which were implanted in the subcutaneous space of MPS I mice in order to evaluate their potential effect as a treatment for this disease. APA microcapsules enclosing genetically modified Baby Hamster Kidney cells overexpressing IDUA were produced and implanted in the subcutaneous space of 4-month-old MPS I mice (Idua -/-). Treatment was performed using two cell concentrations: 8.3 × 107 and 8.3 × 106 cells/mL. Untreated MPS I and normal mice were used as controls. Microcapsules were retrieved and analyzed after treatment. Increased IDUA in the liver, kidney and heart was detected 24 h postimplantation. After 120 days, higher IDUA activity was detected in the liver, kidney and heart, in both groups, whereas GAG accumulation was reduced only in the high cell concentration group. Microcapsules analysis showed blood vessels around them, as well as inflammatory cells and a fibrotic layer. Microencapsulated cells were able to ameliorate some aspects of the disease, indicating their potential as a treatment. To achieve better performance of the microcapsules, improvements such as the modulation of inflammatory response are suggested.
Assuntos
Composição de Medicamentos , Iduronidase/química , Injeções Subcutâneas , Mucopolissacaridose I/tratamento farmacológico , Alginatos/química , Animais , Cápsulas/química , Linhagem Celular , Cricetinae , Glicosaminoglicanos/química , Sistema Imunitário , Inflamação , Rim/efeitos dos fármacos , Lisossomos/química , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Polilisina/análogos & derivados , Polilisina/química , Proteínas Recombinantes/química , Distribuição TecidualRESUMO
Mucopolysaccharidosis type I (MPS I) is an autosomal disease caused by alpha-L-iduronidase deficiency. This study proposed the use of cationic nanoemulsions as non-viral vectors for a plasmid (pIDUA) containing the gene that codes for alpha-L-iduronidase. Nanoemulsions composed of medium chain triglycerides (MCT)/1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE)/1,2-dioleoyl-sn-glycero-3-trimethylammonium propane (DOTAP)/1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino(polyethylene glycol)-2000] (DSPE-PEG) were prepared by high pressure homogenization. Formulations were prepared by the adsorption or encapsulation of preformed pIDUA-DOTAP complexes into the oil core of nanoemulsions at different charge ratios. pIDUA complexed was protected from enzymatic degradation by DNase I. The physicochemical characteristics of complexes in protein-containing medium were mainly influenced by the presence of DSPE-PEG. Bragg reflections corresponding to a lamellar organization were identified for blank formulations by energy dispersive X-ray diffraction, which could not be detected after pIDUA complexation. The intravenous injection of these formulations in MPS I knockout mice led to a significant increase in IDUA activity (fluorescence assay) and expression (RT-qPCR) in different organs, especially the lungs and liver. These findings were more significant for formulations prepared at higher charge ratios (+4/-), suggesting a correlation between charge ratio and transfection efficiency. The present preclinical results demonstrated that these nanocomplexes represent a potential therapeutic option for the treatment of MPS I.
Assuntos
Terapia Genética , Iduronidase/genética , Mucopolissacaridose I/terapia , Transfecção/métodos , Animais , Modelos Animais de Doenças , Emulsões , Ácidos Graxos Monoinsaturados/química , Expressão Gênica , Humanos , Iduronidase/química , Iduronidase/metabolismo , Rim/metabolismo , Fígado/metabolismo , Pulmão/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mucopolissacaridose I/genética , Mucopolissacaridose I/metabolismo , Nanoestruturas/química , Fosfatidiletanolaminas/química , Plasmídeos , Polietilenoglicóis/química , Compostos de Amônio Quaternário/química , Baço/metabolismo , Triglicerídeos/químicaRESUMO
PURPOSE: Mucopolysaccharidosis I is a genetic disorder caused by alpha-L-iduronidase deficiency. Its primary treatment is enzyme replacement therapy (ERT), which has limitations such as a high cost and a need for repeated infusions over the patient's lifetime. Considering that nanotechnological approaches may enhance enzyme delivery to organs and can reduce the dosage thereby enhancing ERT efficiency and/or reducing its cost, we synthesized laronidase surface-functionalized lipid-core nanocapsules (L-MLNC). METHODS: L-MLNCs were synthesized by using a metal complex. Size distributions were evaluated by laser diffraction and dynamic light scattering. The kinetic properties, cytotoxicity, cell uptake mechanisms, clearance profile and biodistribution were evaluated. RESULTS: Size distributions showed a D[4,3] of 134 nm and a z-average diameter of 71 nm. L-MLNC enhanced the Vmax and Kcat in comparison with laronidase. L-MLNC is not cytotoxic, and nanocapsule uptake by active transport is not only mediated by mannose-6-phosphate receptors. The clearance profile is better for L-MLNC than for laronidase. A biodistribution analysis showed enhanced enzyme activity in different organs within 4 h and 24 h for L-MLNC. CONCLUSIONS: The use of lipid-core nanocapsules as building blocks to synthesize surface-functionalized nanocapsules represents a new platform for producing decorated soft nanoparticles that are able to modify drug biodistribution.
Assuntos
Terapia de Reposição de Enzimas , Fibroblastos/efeitos dos fármacos , Iduronidase/química , Lipídeos/química , Mucopolissacaridose I/tratamento farmacológico , Nanocápsulas , Animais , Área Sob a Curva , Transporte Biológico , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Química Farmacêutica , Terapia de Reposição de Enzimas/efeitos adversos , Fibroblastos/metabolismo , Fibroblastos/patologia , Iduronidase/administração & dosagem , Iduronidase/genética , Iduronidase/farmacocinética , Iduronidase/toxicidade , Injeções Intravenosas , Taxa de Depuração Metabólica , Camundongos Knockout , Mucopolissacaridose I/enzimologia , Nanomedicina , Tamanho da Partícula , Tecnologia Farmacêutica/métodos , Distribuição TecidualRESUMO
BACKGROUND: Mucopolysaccharidosis type I (MPS I) is a disease caused by deficiency of the enzyme alpha-L-iduronidase (IDUA). Since no treatment is currently available for this disorder, the detection of heterozygotes is very important for genetic counseling and prenatal diagnosis. The objective of the present study was to characterize plasma IDUA from MPS I heterozygotes in an attempt to distinguish it from that of normal individuals. METHODS: We determined the optimum pH, Km, Vmax and Calpha (Vmax/Km) of the reaction and the thermal stability of IDUA at 50 degrees C. RESULTS: MPS I heterozygotes can be separated from normal individuals on the basis of Km, Calpha and thermal stability of the enzyme. CONCLUSIONS: Taking into consideration the clinical status of the homozygous offspring, we were able to subdivide the MPS I heterozygotes into various subgroups (Hurler, Scheie or Hurler/Scheie compound), and verified that the Hurler subgroup had a lower optimum pH for IDUA activity than controls and other MPS I subgroups, and that all MPS I subgroups had higher Km and lower Calpha when compared to controls.