scholarly journals Cathepsin B-associated Activation of Amyloidogenic Pathway in Murine Mucopolysaccharidosis Type I Brain Cortex

2020 ◽  
Vol 21 (4) ◽  
pp. 1459 ◽  
Author(s):  
Gustavo Monteiro Viana ◽  
Esteban Alberto Gonzalez ◽  
Marcela Maciel Palacio Alvarez ◽  
Renan Pelluzzi Cavalheiro ◽  
Cinthia Castro do Nascimento ◽  
...  

Mucopolysaccharidosis type I (MPS I) is caused by genetic deficiency of α-l-iduronidase and impairment of lysosomal catabolism of heparan sulfate and dermatan sulfate. In the brain, these substrates accumulate in the lysosomes of neurons and glial cells, leading to neuroinflammation and neurodegeneration. Their storage also affects lysosomal homeostasis-inducing activity of several lysosomal proteases including cathepsin B (CATB). In the central nervous system, increased CATB activity has been associated with the deposition of amyloid plaques due to an alternative pro-amyloidogenic processing of the amyloid precursor protein (APP), suggesting a potential role of this enzyme in the neuropathology of MPS I. In this study, we report elevated levels of protein expression and activity of CATB in cortex tissues of 6-month-old MPS I (Idua -/- mice. Besides, increased CATB leakage from lysosomes to the cytoplasm of Idua -/- cortical pyramidal neurons was indicative of damaged lysosomal membranes. The increased CATB activity coincided with an elevated level of the 16-kDa C-terminal APP fragment, which together with unchanged levels of β-secretase 1 was suggestive for the role of this enzyme in the amyloidogenic APP processing. Neuronal accumulation of Thioflavin-S-positive misfolded protein aggregates and drastically increased levels of neuroinflammatory glial fibrillary acidic protein (GFAP)-positive astrocytes and CD11b-positive activated microglia were observed in Idua -/- cortex by confocal fluorescent microscopy. Together, our results point to the existence of a novel CATB-associated alternative amyloidogenic pathway in MPS I brain induced by lysosomal storage and potentially leading to neurodegeneration.

2020 ◽  
Vol 6 (1) ◽  
pp. 10 ◽  
Author(s):  
Dawn S. Peck ◽  
Jean M. Lacey ◽  
Amy L. White ◽  
Gisele Pino ◽  
April L. Studinski ◽  
...  

Enzyme-based newborn screening for Mucopolysaccharidosis type I (MPS I) has a high false-positive rate due to the prevalence of pseudodeficiency alleles, often resulting in unnecessary and costly follow up. The glycosaminoglycans (GAGs), dermatan sulfate (DS) and heparan sulfate (HS) are both substrates for α-l-iduronidase (IDUA). These GAGs are elevated in patients with MPS I and have been shown to be promising biomarkers for both primary and second-tier testing. Since February 2016, we have measured DS and HS in 1213 specimens submitted on infants at risk for MPS I based on newborn screening. Molecular correlation was available for 157 of the tested cases. Samples from infants with MPS I confirmed by IDUA molecular analysis all had significantly elevated levels of DS and HS compared to those with confirmed pseudodeficiency and/or heterozygosity. Analysis of our testing population and correlation with molecular results identified few discrepant outcomes and uncovered no evidence of false-negative cases. We have demonstrated that blood spot GAGs analysis accurately discriminates between patients with confirmed MPS I and false-positive cases due to pseudodeficiency or heterozygosity and increases the specificity of newborn screening for MPS I.


Cells ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 129
Author(s):  
Concetta De Filippis ◽  
Barbara Napoli ◽  
Laura Rigon ◽  
Giulia Guarato ◽  
Reinhard Bauer ◽  
...  

Deficit of the IDUA (α-L-iduronidase) enzyme causes the lysosomal storage disorder mucopolysaccharidosis type I (MPS I), a rare pediatric neurometabolic disease, due to pathological variants in the IDUA gene and is characterized by the accumulation of the undegraded mucopolysaccharides heparan sulfate and dermatan sulfate into lysosomes, with secondary cellular consequences that are still mostly unclarified. Here, we report a new fruit fly RNAi-mediated knockdown model of a IDUA homolog (D-idua) displaying a phenotype mimicking some typical molecular features of Lysosomal Storage Disorders (LSD). In this study, we showed that D-idua is a vital gene in Drosophila and that ubiquitous reduction of its expression leads to lethality during the pupal stage, when the precise degradation/synthesis of macromolecules, together with a functional autophagic pathway, are indispensable for the correct development to the adult stage. Tissue-specific analysis of the D-idua model showed an increase in the number and size of lysosomes in the brain and muscle. Moreover, the incorrect acidification of lysosomes led to dysfunctional lysosome-autophagosome fusion and the consequent block of autophagy flux. A concomitant metabolic drift of glycolysis and lipogenesis pathways was observed. After starvation, D-idua larvae showed a quite complete rescue of both autophagy/lysosome phenotypes and metabolic alterations. Metabolism and autophagy are strictly interconnected vital processes that contribute to maintain homeostatic control of energy balance, and little is known about this regulation in LSDs. Our results provide new starting points for future investigations on the disease’s pathogenic mechanisms and possible pharmacological manipulations.


2020 ◽  
Vol 32 (3) ◽  
pp. 304 ◽  
Author(s):  
Cinthia Castro do Nascimento ◽  
Odair Aguiar ◽  
Gustavo Monteiro Viana ◽  
Vânia D'Almeida

Mucopolysaccharidosis type I (MPS I) is a lysosomal storage disease caused by a deficiency of the lysosomal hydrolase, α-L-iduronidase (IDUA). IDUA degrades heparan and dermatan sulfates, two types of glycosaminoglycan (GAG), important signalling and structural molecules of the extracellular matrix. Because many cell types store GAGs, MPS I has been investigated in human and animal models. Enzyme replacement therapy is available for MPS I patients and has improved their life expectancy, allowing them to achieve reproductive age. The aim of this study was to evaluate epididymal and sperm morphology and function in a murine model of MPS I. We used C57BL Idua+/+ and Idua−/− adult male mice (6 months old) to investigate epididymal morphology, sperm ultrastructure, GAG characterisation and mating competence. Epithelial GAG storage, especially in the cauda epididymidis, was seen in Idua−/− mice. Regardless of the morphologic change and GAG storage found in the cauda epididymis, sperm morphology and motility were normal, similar to wild types. In the interstitium, vacuolated cells were found in addition to deposits of GAGs. Mating was not impaired in Idua−/− males and litter sizes were similar between groups. At the time point of the disease evaluated, the deficiency in IDUA affected the morphology of the epididymis in male Idua−/− mice, whereas sperm appearance and motility and the male’s capacity to mate and impregnate females were preserved.


2019 ◽  
Author(s):  
Ana Beatriz Barbosa Mendes ◽  
Cinthia Castro do Nascimento ◽  
Vânia D’ Almeida

AbstractMucopolysaccharidosis Type I (MPS I) is a rare genetic lysosomal storage disease caused by a mutation of IDUA gene. IDUA codes for α-L-iduronidase (IDUA), a lysosomal hydrolase that degrades glycosaminoglycans (GAGs): heparan sulphate and dermatan sulphate. GAGs are structural and signalling molecules that have a crucial role in controlling a variety of cell functions and their interaction with extracellular matrix. Because of GAG’s widespread action in cellular metabolism, MPS I is a progressive and disabling multisystemic disorder. Nowadays, the therapies availability allowed patients to reach the adult life and the consequences of the disease in their reproductive system is still little known. We aimed to investigate whether IDUA disruption influences sexual behaviour and sexual steroid production in male and female MPS I mice. We used 3 and 6-month-old male and 3-month-old female Idua+/_ and Idua−/− mice to evaluate typical rodent copulatory behaviours. In males we observed the frequency and latency of mounts, intromissions and ejaculations. In females we evaluated the lordosis quotient. We also analysed the locomotor capacity of mice in the open field test, since copulatory behaviour requires mobility. We also quantified steroidal hormonal levels in plasmatic samples. We detected an increase in the latencies of intromissions in male copulatory behaviour of Idua−/− males when compared to Idua+/_. However, the number of intromissions was not statistically different between groups. No parameter of female sexual behaviour was statistically different between control and knockout females. In both sexes, we detected diminished mobility in Idua−/− mice. Plasma hormone levels did not differ between Idua+/_ and Idua−/− mice, both in males and females. We concluded that in the considered time point of MPS I progression, mice are able to perform sexual behaviour, but the male performance may be influenced due to the motor disability predicted to MPS I.


PLoS ONE ◽  
2019 ◽  
Vol 14 (12) ◽  
pp. e0220429 ◽  
Author(s):  
Ana Barbosa Mendes ◽  
Cinthia Castro do Nascimento ◽  
Vânia D’Almeida

2020 ◽  
Vol 28 (3) ◽  
pp. 279-286
Author(s):  
Camelia Alkhzouz ◽  
Cecilia Lazea ◽  
Diana Miclea ◽  
Carmen Asavoaie ◽  
Ioana Nascu ◽  
...  

AbstractBackground: Mucopolysaccharidosis type I (MPS I) is an autosomal recessive lysosomal storage disorder caused by a deficiency of α-L-iduronidase (IDUA), which leads to the accumulation of partially digested glycosaminoglycans (dermatan sulfate and heparan sulfate) in the lysosomes and induces multisystemic alteration. Hurler (severe), Scheie (mild), and Hurler/Scheie (intermediate) syndromes are clinical subtypes of MPS-I. To date, more than 290 IDUA mutations have been reported. The purpose of this study was to present the clinical and genetic characteristics of Romanian MPS I syndrome patients and their genotype-phenotype correlation.Patients and methods: Seven patients (5 girls and 2 boys) with MPS type I, belonging to 4 unrelated families, aged 0,75-17.9 years, were enrolled. The study methods consisted in: clinical and standard auxological assessment, bone radiographs, joint ultrasonography, goniometry, neurological and psychological evaluation, hepatic and splenic ultrasonography, cardiological evaluation, otorhinolaryngology examination, ophthalmological examination, spirometry, α-L-iduronidase enzyme activity assay and molecular analysis.Results: The seven patients originated from 4 unrelated families, three patients with severe, two patients with intermediate and two with attenuated clinical phenotype. Each patient presented the classical picture of MPS type I picture, represented by: variable coarse facial features, arthropathy, hepatosplenomegaly, cardiac involvement, respiratory dysfunction and neurological impairment. Five patological variants, three point mutations (p.Q70 *, p.I238Q and p.K324R), two deletion c.1045_1047delGAC, c.46_57delTCGCTCCTG) and an insertion (c.1389 insC) were identified in both alleles of the ADUA gene in homozygous or heterozygous form. Two novel mutations (p.K324R and c.1389 insC) were reported. The p.Q70*(c.208C>T) variant was identified in 2 families with severe form of disease (Hurler syndrome) in homozygous status in one family and in compound heterozygous status in the other family.Conclusion: The p.Q70* missense variant was the most frequent, correlated in all the cases who presented it with severe form, Hurler syndrome, the other mutations being usually isolated and particular for each patient, associated in our patients with less severe MPS I phenotype, as Hurler-Scheie or Scheie syndrome. The results of this study indicated the mutational heterogeneity of the IDUA gene and the difficulty to indicate some correlation between the genotype and phenotype in MPS I patients.


2017 ◽  
Vol 27 ◽  
pp. 45-50 ◽  
Author(s):  
Guilherme Baldo ◽  
Angela Maria Vicente Tavares ◽  
Esteban Gonzalez ◽  
Edina Poletto ◽  
Fabiana Quoos Mayer ◽  
...  

2021 ◽  
Vol 12 (3) ◽  
pp. 69-83
Author(s):  
Victoria N. Gorbunova ◽  
Natalia V. Buchinskaia

Mucopolysaccharidosis (MPS) are a genetically heterogeneous group of rare monogenic metabolic diseases associated with hereditary insufficiency of lysosomal enzymes involved in the catabolism of glycosaminoglycans, or mucopolysaccharides. The pathogenesis of MPS is due to the accumulation of non-cleaved glycosaminoglycans in lysosomes, which can destroy cells. All MPS are characterized by a polysystemic manifestation, the simultaneous involvement of many organs and tissues in the pathological process, first of all, connective tissues, bones and cartilaginous. This review presents the epidemiology, clinical, biochemical, and molecular genetic characteristics of MPS types I and II, caused by the recessive mutations in the alpha-L-iduronidase and iduronate-2-sulfatase genes, respectively, and by the accumulation of dermatan and heparan sulfate. Each of these diseases is characterized by clinical polymorphism, especially observed in MPS I, which often manifests in a severe form of Hurler syndrome, but can also occur in a milder form of Scheie syndrome. Currently, there is an increased interest in MPS in the world due to the identification of the spectrum and frequencies of mutations in theIDUAandIDSgenes in various populations, including in Russia, and the practical availability of methods for individual molecular diagnostics. The description of the existing experimental models, their role in the study of the biochemical basis of the pathogenesis of these severe hereditary diseases and the development of various therapeutic approaches are given. Discusses the possibility of early diagnosis of MPS I and II types based on neonatal screening in order to increase the effectiveness of their prevention and treatment, as well as the advantages and disadvantages of the main approaches to the treatment of these serious diseases, such as hematopoietic stem cell transplantation, enzyme replacement and substrate-reducing therapy. A clinical example of a combination therapy for a severe form of mucopolysaccharidosis type I Hurler syndrome is presented


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