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Genetic and Metabolic Molecular Research of Lysosomal Storage Disease 3.0

A special issue of International Journal of Molecular Sciences (ISSN 1422-0067). This special issue belongs to the section "Molecular Pathology, Diagnostics, and Therapeutics".

Deadline for manuscript submissions: closed (31 January 2024) | Viewed by 22570

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Department of Molecular Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland
Interests: gene expression regulation; DNA replication; bacteriophages; plasmids; human genetic diseases; neurodegeneration
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Special Issue Information

Dear Colleagues, 

Lysosomal storage diseases (LSD) are a group of inherited metabolic disorders in which the defects of various lysosomal enzymes and regulatory proteins result in the accumulation of different macromolecules in these organelles. Over 50 LSD are described in the literature, and they are among the most intensively studied genetic disorders. They are also model genetic diseases for the development of various therapeutic approaches. The introduction of enzyme replacement therapy for LSD created a breakthrough in treating genetic diseases, and several different therapeutic options are currently being studied, including hematopoietic stem cell transplantation, gene therapy, substrate reduction therapy, and others. However, to develop new therapies, the molecular mechanisms of LSD must be understood in great detail. Now is the time for extensive molecular research on LSD. This Special Issue is devoted to publishing the results of such studies, including basic research on the molecular mechanisms of LSD, translational studies on novel therapies, and clinical investigations performed at the molecular level. Review articles on all these aspects are also welcome. Therefore, this Special Issue shall provide a comprehensive view on molecular aspects of various LSD.

Although the pathophysiology, mechanism, and therapeutic strategies of lysosomal storage diseases are topics covered by another Special Issue of IJMS, this issue is devoted to presenting research on the molecular aspects of these diseases. The Editors consider that this group of diseases is at the forefront of genetic and metabolic disorders that are studied on the molecular level, and our understanding of molecular mechanisms, molecular pharmacology, and clinical aspects on the molecular level is crucial for further research in this field, as well as for opening new ways of thinking about other, currently less understood diseases.

Prof. Dr. Grzegorz Wegrzyn
Guest Editor

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Keywords

  • lysosomal storage diseases
  • molecular mechanisms of genetic disorders metabolic diseases
  • accumulation of macromolecules in cells
  • enzyme replacement therapy
  • hematopoietic stem cell transplantation gene therapy
  • substrate reduction therapy
  • translational research
  • novel therapies for genetic diseases

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Published Papers (11 papers)

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Research

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14 pages, 1376 KiB  
Article
A Brazilian Rare-Disease Center’s Experience with Glucosylsphingosine (lyso-Gb1) in Patients with Gaucher Disease: Exploring a Novel Correlation with IgG Levels in Plasma and a Biomarker Measurement in CSF
by Matheus Vernet Machado Bressan Wilke, Gabrielle Dineck Iop, Larissa Faqueti, Layzon Antonio Lemos da Silva, Francyne Kubaski, Fabiano O. Poswar, Kristiane Michelin-Tirelli, Dévora Randon, Wyllians Vendramini Borelli, Roberto Giugliani and Ida Vanessa D. Schwartz
Int. J. Mol. Sci. 2024, 25(5), 2870; https://doi.org/10.3390/ijms25052870 - 1 Mar 2024
Viewed by 1589
Abstract
Gaucher disease (GD, OMIM 230800) is one of the most common lysosomal disorders, being caused by the deficient activity of the enzyme acid β-glucocerebrosidase (Gcase). Three clinical forms of Gaucher’s disease (GD) are classified based on neurological involvement. Type 1 (GD1) is non-neuronopathic, [...] Read more.
Gaucher disease (GD, OMIM 230800) is one of the most common lysosomal disorders, being caused by the deficient activity of the enzyme acid β-glucocerebrosidase (Gcase). Three clinical forms of Gaucher’s disease (GD) are classified based on neurological involvement. Type 1 (GD1) is non-neuronopathic, while types 2 (GD2) and 3 (GD3) are neuronopathic forms. Gcase catalyzes the conversion of glucosylceramide (GlcCer) into ceramide and glucose. As GlcCer accumulates in lysosomal macrophages, it undergoes deacylation to become glycosylsphingosine (lyso-Gb1), which has shown to be a useful and reliable biomarker for the diagnosis and monitoring of treated and untreated patients with GD. Multiple myeloma (MM) is one of the leading causes of cancer-related death among patients with GD and monoclonal gammopathy of undetermined significance (MGUS) is a non-neoplastic condition that can be a telltale sign of a B clonal proliferation caused by the chronic activation of B cells. This study aimed to quantify Lyso-Gb1 levels in dried blood spots (DBS) and cerebrospinal fluid (CSF) as biomarkers for Gaucher disease (GD) and discuss the association of this biomarker with other clinical parameters. This is a mixed-methods study incorporating both cross-sectional and longitudinal elements within a cohort design with a convenience-sampling strategy. Data collection took place from January 2012 to March 2023. Lyso-Gb1 extraction from DBS involved the use of a methanol–acetonitrile–water mixture, followed by incubation and centrifugation. Analysis was performed using UPLC-MS/MS with MassLynx software version 4.2 and the control group for the DBS measurements included general newborns. CSF Lyso-Gb1 was extracted using ethyl acetate, analyzed by UPLC-MS/MS with a calibration curve, and expressed in pmol/L. Lysosomal activity in CSF was assessed by measuring chitotriosidase (Cht), and other lysosomal enzyme activities were assessed as previously described in the literature. Patients with metachromatic leukodystrophy (MLD) were used as controls. Thirty-two treated patients (twenty-nine GD1 and three GD3, all on ERT except for one GD type on SRT with eliglustat) and three untreated patients (one GD1, one GD2, and one GD3) were included. When analyzing only the treated GD1 group, a significant correlation was found between lyso-Gb1 and age (rho = −0.447, p = 0.001), ChT, and IgG levels (rho = 0.73, p < 0.001; and rho = 0.36, p = 0.03, respectively). Five GD1 patients (three females, mean age 40 years) also had their CSF collected and analyzed. The average measurement of lyso-Gb1 in CSF was 94 pmol/L (range: 57.1–157.9 pmol/L) versus <6.2 pmol/L in the control group (MLD). This is the first time, to the best of our knowledge, that lyso-Gb1 has been associated with IgG levels. While this finding reflects a risk for MGUS or MM and not only chronic plasma B-cell activation, it still requires further studies. Moreover, the analysis of CSF lyso-Gb1 levels in GD1 patients was demonstrated to be significantly higher than the control group. This raises the hypothesis that CSF lyso-Gb1 may serve as a valuable indicator for neurological involvement in GD, providing insights into the potential implications for neurological manifestations in GD, including GD1. The correlation between lyso-Gb1 and ChT levels in treated GD1 patients further underscores the interconnectedness of lysosomal markers and their relevance in monitoring. Full article
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15 pages, 5335 KiB  
Article
A Comparative Biochemical and Pathological Evaluation of Brain Samples from Knock-In Murine Models of Gaucher Disease
by Makaila L. Furderer, Bahafta Berhe, Tiffany C. Chen, Stephen Wincovitch, Xuntian Jiang, Nahid Tayebi, Ellen Sidransky and Tae-Un Han
Int. J. Mol. Sci. 2024, 25(3), 1827; https://doi.org/10.3390/ijms25031827 - 2 Feb 2024
Cited by 1 | Viewed by 1895
Abstract
Gaucher disease (GD) is a lysosomal storage disorder stemming from biallelic mutations in GBA1, characterized by glucocerebrosidase dysfunction and glucocerebroside and glucosylsphingosine accumulation. Since phenotypes of murine models of GD often differ from those in patients, the careful characterization of Gba1 mutant [...] Read more.
Gaucher disease (GD) is a lysosomal storage disorder stemming from biallelic mutations in GBA1, characterized by glucocerebrosidase dysfunction and glucocerebroside and glucosylsphingosine accumulation. Since phenotypes of murine models of GD often differ from those in patients, the careful characterization of Gba1 mutant mice is necessary to establish their ability to model GD. We performed side-by-side comparative biochemical and pathologic analyses of four murine Gba1 models with genotypes L444P/L444P (p.L483P/p.L483P), L444P/null, D409H/D409H (p.D448H/p.D448H) and D409H/null, along with matched wildtype mice, all with the same genetic background and cage conditions. All mutant mice exhibited significantly lower glucocerebrosidase activity (p < 0.0001) and higher glucosylsphingosine levels than wildtype, with the lowest glucocerebrosidase and the highest glucosylsphingosine levels in mice carrying a null allele. Although glucocerebrosidase activity in L444P and D409H mice was similar, D409H mice showed more lipid accumulation. No Gaucher or storage-like cells were detected in any of the Gba1 mutant mice. Quantification of neuroinflammation, dopaminergic neuronal loss, alpha-synuclein levels and motor behavior revealed no significant findings, even in aged animals. Thus, while the models may have utility for testing the effect of different therapies on enzymatic activity, they did not recapitulate the pathological phenotype of patients with GD, and better models are needed. Full article
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18 pages, 2285 KiB  
Article
Long-Term Evaluation of Biomarkers in the Czech Cohort of Gaucher Patients
by Věra Malinová, Helena Poupětová, Martin Řeboun, Lenka Dvořáková, Stella Reichmannová, Ivana Švandová, Lenka Murgašová, David C. Kasper and Martin Magner
Int. J. Mol. Sci. 2023, 24(19), 14440; https://doi.org/10.3390/ijms241914440 - 22 Sep 2023
Viewed by 1190
Abstract
A personalized treatment decision for Gaucher disease (GD) patients should be based on relevant markers that are specific to GD, play a direct role in GD pathophysiology, exhibit low genetic variation, reflect the therapy, and can be used for all patients. Thirty-four GD [...] Read more.
A personalized treatment decision for Gaucher disease (GD) patients should be based on relevant markers that are specific to GD, play a direct role in GD pathophysiology, exhibit low genetic variation, reflect the therapy, and can be used for all patients. Thirty-four GD patients treated with enzyme replacement therapy (ERT) or substrate reduction therapy (SRT) were analyzed for platelet count, chitotriosidase, and tartrate-resistant acid phosphatase activity in plasma samples, and quantitative measurement of Lyso-Gb1 was performed in dried blood spots. In our ERT and SRT study cohorts, plasma lyso-GL1 correlated significantly with chito-triosidase (ERT: r = 0.55, p < 0.001; SRT: r = 0.83, p < 0.001) and TRAP (ERT: r = 0.34, p < 0.001; SRT: r = 0.88, p < 0.001), irrespective of treatment method. A platelet count increase was associated with a Lyso-Gb1 decrease in both treatment groups (ERT: p = 0.021; SRT: p = 0.028). The association of Lyso-Gb1 with evaluated markers was stronger in the SRT cohort. Our results indicate that ERT and SRT in combination or in a switch manner could offer the potential of individual drug effectiveness for particular GD symptoms. Combination of the key biomarker of GD, Lyso-Gb1, with other biomarkers can offer improved response assessment to long-term therapy. Full article
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12 pages, 1020 KiB  
Article
Enhanced Efficiency of the Basal and Induced Apoptosis Process in Mucopolysaccharidosis IVA and IVB Human Fibroblasts
by Joanna Brokowska, Lidia Gaffke, Karolina Pierzynowska and Grzegorz Węgrzyn
Int. J. Mol. Sci. 2023, 24(18), 14119; https://doi.org/10.3390/ijms241814119 - 14 Sep 2023
Cited by 3 | Viewed by 1203
Abstract
Morquio disease, also called mucopolysaccharidosis IV (MPS IV), belongs to the group of lysosomal storage diseases (LSD). Due to deficiencies in the activities of galactose-6-sulfate sulfatase (in type A) or β-galactosidase (in type B), arising from mutations in GALNS or GLB1, respectively, [...] Read more.
Morquio disease, also called mucopolysaccharidosis IV (MPS IV), belongs to the group of lysosomal storage diseases (LSD). Due to deficiencies in the activities of galactose-6-sulfate sulfatase (in type A) or β-galactosidase (in type B), arising from mutations in GALNS or GLB1, respectively, keratan sulfate (one of glycosaminoglycans, GAGs) cannot be degraded efficiently and accumulates in lysosomes. This primary defect leads to many cellular dysfunctions which then cause specific disease symptoms. Recent works have indicated that different secondary effects of GAG accumulation might significantly contribute to the pathomechanisms of MPS. Apoptosis is among the cellular processes that were discovered to be affected in MPS cells on the basis of transcriptomic studies and some cell biology experiments. However, Morquio disease is the MPS type which is the least studied in light of apoptosis dysregulation, while RNA-seq analyses suggested considerable changes in the expression of genes involved in apoptosis in MPS IVA and IVB fibroblasts. Here we demonstrate that cytochrome c release from mitochondria is more efficient in MPS IVA and IVB fibroblasts relative to control cells, both under the standard cultivation conditions and after treatment with staurosporine, an apoptosis inducer. This indication of apoptosis stimulation was corroborated by measurements of the levels of caspases 9, 3, 6, and 7, as well as PARP, cleaved at specific sites, in Morquio disease and control fibroblasts. The more detailed analyses of the transcriptomic data revealed which genes related to apoptosis are down- and up-regulated in MPS IVA and IVB fibroblasts. We conclude that apoptosis is stimulated in Morquio disease under both standard cell culture conditions and after induction with staurosporine which may contribute to the pathomechanism of this disorder. Dysregulation of apoptosis in other MPS types is discussed. Full article
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13 pages, 4156 KiB  
Article
Femoral Structure and Biomechanical Characteristics in Sanfilippo Syndrome Type-B Mice
by Frederick James Ashby, Evelyn J. Castillo, Yan Ludwig, Natalia K. Andraka, Cong Chen, Julia C. Jamieson, Nadia Kabbej, John D. Sommerville, Jose I. Aguirre and Coy D. Heldermon
Int. J. Mol. Sci. 2023, 24(18), 13988; https://doi.org/10.3390/ijms241813988 - 12 Sep 2023
Viewed by 1400
Abstract
Sanfilippo syndrome Type-B, also known as mucopolysaccharidosis IIIB (MPS IIIB), accounts for approximately one-third of all Sanfilippo syndrome patients and is characterized by a similar natural history as Type-A. Patients suffer from developmental regression, bone malformation, organomegaly, GI distress, and profound neurological deficits. [...] Read more.
Sanfilippo syndrome Type-B, also known as mucopolysaccharidosis IIIB (MPS IIIB), accounts for approximately one-third of all Sanfilippo syndrome patients and is characterized by a similar natural history as Type-A. Patients suffer from developmental regression, bone malformation, organomegaly, GI distress, and profound neurological deficits. Despite human trials of enzyme replacement therapy (ERT) (SBC-103, AX250) in MPS IIIB, there is currently no FDA approved treatment and a few palliative options. The major concerns of ERT and gene therapy for the treatment of bone malformation are the inadequate biodistribution of the missing enzyme, N-acetyl-α-glucosaminidase (NAGLU), and that the skeleton is a poorly hit target tissue in ERT and gene therapy. Each of the four known human types of MPS III (A, B, C, and D) is usually regarded as having mild bone manifestations, yet it remains poorly characterized. This study aimed to determine bone mineral content (BMC), volumetric bone mineral density (vBMD), and biomechanical properties in femurs MPS IIIB C57BL/6 mice compared to phenotypic control C57BL/6 mice. Significant differences were observed in MPS IIIB mice within various cortical and cancellous bone parameters for both males and females (p < 0.05). Here, we establish some osteogenic manifestations of MPS IIIB within the mouse model by radiographic and biomechanical tests, which are also differentially affected by age and sex. This suggests that some skeletal features of the MPS IIIB mouse model may be used as biomarkers of peripheral disease correction for preclinical treatment of MPS IIIB. Full article
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16 pages, 4411 KiB  
Article
From Acid Alpha-Glucosidase Deficiency to Autophagy: Understanding the Bases of POMPE Disease
by Valentina Sánchez-Porras, Johana Maria Guevara-Morales and Olga Yaneth Echeverri-Peña
Int. J. Mol. Sci. 2023, 24(15), 12481; https://doi.org/10.3390/ijms241512481 - 5 Aug 2023
Cited by 1 | Viewed by 2414
Abstract
Pompe disease (PD) is caused by mutations in the GAA gene, which encodes the lysosomal enzyme acid alpha-glucosidase, causing lysosomal glycogen accumulation, mainly in muscular tissue. Autophagic buildup is considered the main factor affecting skeletal muscle, although other processes are also involved. Uncovering [...] Read more.
Pompe disease (PD) is caused by mutations in the GAA gene, which encodes the lysosomal enzyme acid alpha-glucosidase, causing lysosomal glycogen accumulation, mainly in muscular tissue. Autophagic buildup is considered the main factor affecting skeletal muscle, although other processes are also involved. Uncovering how these mechanisms are interconnected could be an approximation to address long-lasting concerns, like the differential skeletal and cardiac involvement in each clinical phenotype. In this sense, a network reconstruction based on a comprehensive literature review of evidence found in PD enriched with the STRING database and other scientific articles is presented. The role of autophagic lysosome reformation, PGC-1α, MCOLN1, calcineurin, and Keap1 as intermediates between the events involved in the pathologic cascade is discussed and contextualized within their relationship with mTORC1/AMPK. The intermediates and mechanisms found open the possibility of new hypotheses and questions that can be addressed in future experimental studies of PD. Full article
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20 pages, 2388 KiB  
Article
Triamterene Functions as an Effective Nonsense Suppression Agent for MPS I-H (Hurler Syndrome)
by Amna Siddiqui, Halil Dundar, Jyoti Sharma, Aneta Kaczmarczyk, Josh Echols, Yanying Dai, Chuanxi Richard Sun, Ming Du, Zhong Liu, Rui Zhao, Tim Wood, Shalisa Sanders, Lynn Rasmussen, James Robert Bostwick, Corinne Augelli-Szafran, Mark Suto, Steven M. Rowe, David M. Bedwell and Kim M. Keeling
Int. J. Mol. Sci. 2023, 24(5), 4521; https://doi.org/10.3390/ijms24054521 - 24 Feb 2023
Viewed by 2163
Abstract
Mucopolysaccharidosis I-Hurler (MPS I-H) is caused by the loss of α-L-iduronidase, a lysosomal enzyme that degrades glycosaminoglycans. Current therapies cannot treat many MPS I-H manifestations. In this study, triamterene, an FDA-approved, antihypertensive diuretic, was found to suppress translation termination at a nonsense mutation [...] Read more.
Mucopolysaccharidosis I-Hurler (MPS I-H) is caused by the loss of α-L-iduronidase, a lysosomal enzyme that degrades glycosaminoglycans. Current therapies cannot treat many MPS I-H manifestations. In this study, triamterene, an FDA-approved, antihypertensive diuretic, was found to suppress translation termination at a nonsense mutation associated with MPS I-H. Triamterene rescued enough α-L-iduronidase function to normalize glycosaminoglycan storage in cell and animal models. This new function of triamterene operates through premature termination codon (PTC) dependent mechanisms that are unaffected by epithelial sodium channel activity, the target of triamterene’s diuretic function. Triamterene represents a potential non-invasive treatment for MPS I-H patients carrying a PTC. Full article
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Review

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17 pages, 1335 KiB  
Review
Alterations in Proteostasis Mechanisms in Niemann–Pick Type C Disease
by Iris Valeria Servín Muñoz, Daniel Ortuño-Sahagún, Christian Griñán-Ferré, Mercè Pallàs and Celia González-Castillo
Int. J. Mol. Sci. 2024, 25(7), 3806; https://doi.org/10.3390/ijms25073806 - 29 Mar 2024
Cited by 1 | Viewed by 2109
Abstract
Niemann–Pick Type C (NPC) represents an autosomal recessive disorder with an incidence rate of 1 in 150,000 live births, classified within lysosomal storage diseases (LSDs). The abnormal accumulation of unesterified cholesterol characterizes the pathophysiology of NPC. This phenomenon is not unique to NPC, [...] Read more.
Niemann–Pick Type C (NPC) represents an autosomal recessive disorder with an incidence rate of 1 in 150,000 live births, classified within lysosomal storage diseases (LSDs). The abnormal accumulation of unesterified cholesterol characterizes the pathophysiology of NPC. This phenomenon is not unique to NPC, as analogous accumulations have also been observed in Alzheimer’s disease, Parkinson’s disease, and other neurodegenerative disorders. Interestingly, disturbances in the folding of the mutant protein NPC1 I1061T are accompanied by the aggregation of proteins such as hyperphosphorylated tau, α-synuclein, TDP-43, and β-amyloid peptide. These accumulations suggest potential disruptions in proteostasis, a regulatory process encompassing four principal mechanisms: synthesis, folding, maintenance of folding, and protein degradation. The dysregulation of these processes leads to excessive accumulation of abnormal proteins that impair cell function and trigger cytotoxicity. This comprehensive review delineates reported alterations across proteostasis mechanisms in NPC, encompassing changes in processes from synthesis to degradation. Additionally, it discusses therapeutic interventions targeting pharmacological facets of proteostasis in NPC. Noteworthy among these interventions is valproic acid, a histone deacetylase inhibitor (HDACi) that modulates acetylation during NPC1 synthesis. In addition, various therapeutic options addressing protein folding modulation, such as abiraterone acetate, DHBP, calnexin, and arimoclomol, are examined. Additionally, treatments impeding NPC1 degradation, exemplified by bortezomib and MG132, are explored as potential strategies. This review consolidates current knowledge on proteostasis dysregulation in NPC and underscores the therapeutic landscape targeting diverse facets of this intricate process. Full article
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38 pages, 3780 KiB  
Review
Molecular Mechanisms in Pathophysiology of Mucopolysaccharidosis and Prospects for Innovative Therapy
by Yasuhiko Ago, Estera Rintz, Krishna Sai Musini, Zhengyu Ma and Shunji Tomatsu
Int. J. Mol. Sci. 2024, 25(2), 1113; https://doi.org/10.3390/ijms25021113 - 17 Jan 2024
Cited by 6 | Viewed by 3836
Abstract
Mucopolysaccharidoses (MPSs) are a group of inborn errors of the metabolism caused by a deficiency in the lysosomal enzymes required to break down molecules called glycosaminoglycans (GAGs). These GAGs accumulate over time in various tissues and disrupt multiple biological systems, including catabolism of [...] Read more.
Mucopolysaccharidoses (MPSs) are a group of inborn errors of the metabolism caused by a deficiency in the lysosomal enzymes required to break down molecules called glycosaminoglycans (GAGs). These GAGs accumulate over time in various tissues and disrupt multiple biological systems, including catabolism of other substances, autophagy, and mitochondrial function. These pathological changes ultimately increase oxidative stress and activate innate immunity and inflammation. We have described the pathophysiology of MPS and activated inflammation in this paper, starting with accumulating the primary storage materials, GAGs. At the initial stage of GAG accumulation, affected tissues/cells are reversibly affected but progress irreversibly to: (1) disruption of substrate degradation with pathogenic changes in lysosomal function, (2) cellular dysfunction, secondary/tertiary accumulation (toxins such as GM2 or GM3 ganglioside, etc.), and inflammatory process, and (3) progressive tissue/organ damage and cell death (e.g., skeletal dysplasia, CNS impairment, etc.). For current and future treatment, several potential treatments for MPS that can penetrate the blood–brain barrier and bone have been proposed and/or are in clinical trials, including targeting peptides and molecular Trojan horses such as monoclonal antibodies attached to enzymes via receptor-mediated transport. Gene therapy trials with AAV, ex vivo LV, and Sleeping Beauty transposon system for MPS are proposed and/or underway as innovative therapeutic options. In addition, possible immunomodulatory reagents that can suppress MPS symptoms have been summarized in this review. Full article
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14 pages, 1240 KiB  
Review
Mucopolysaccharidosis IVA: Current Disease Models and Drawbacks
by Andrés Felipe Leal, Carlos Javier Alméciga-Díaz and Shunji Tomatsu
Int. J. Mol. Sci. 2023, 24(22), 16148; https://doi.org/10.3390/ijms242216148 - 9 Nov 2023
Cited by 3 | Viewed by 1812
Abstract
Mucopolysaccharidosis IVA (MPS IVA) is a rare disorder caused by mutations in the N-acetylgalactosamine-6-sulfate-sulfatase (GALNS) encoding gene. GALNS leads to the lysosomal degradation of the glycosaminoglyccreasans keratan sulfate and chondroitin 6-sulfate. Impaired GALNS enzymes result in skeletal and non-skeletal complications in [...] Read more.
Mucopolysaccharidosis IVA (MPS IVA) is a rare disorder caused by mutations in the N-acetylgalactosamine-6-sulfate-sulfatase (GALNS) encoding gene. GALNS leads to the lysosomal degradation of the glycosaminoglyccreasans keratan sulfate and chondroitin 6-sulfate. Impaired GALNS enzymes result in skeletal and non-skeletal complications in patients. For years, the MPS IVA pathogenesis and the assessment of promising drugs have been evaluated using in vitro (primarily fibroblasts) and in vivo (mainly mouse) models. Even though value information has been raised from those studies, these models have several limitations. For instance, chondrocytes have been well recognized as primary cells affected in MPS IVA and responsible for displaying bone development impairment in MPS IVA patients; nonetheless, only a few investigations have used those cells to evaluate basic and applied concepts. Likewise, current animal models are extensively represented by mice lacking GALNS expression; however, it is well known that MPS IVA mice do not recapitulate the skeletal dysplasia observed in humans, making some comparisons difficult. This manuscript reviews the current in vitro and in vivo MPS IVA models and their drawbacks. Full article
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Other

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8 pages, 609 KiB  
Case Report
Late-Onset Pompe Disease with Normal Creatine Kinase Levels: The Importance of Rheumatological Suspicion
by Daniela Marotto, Marta Moschetti, Alessia Lo Curto, Anna M. Spezzigu, Miriam Giacomarra, Emanuela M. Marsana, Carmela Zizzo, Giovanni Duro and Paolo Colomba
Int. J. Mol. Sci. 2023, 24(21), 15924; https://doi.org/10.3390/ijms242115924 - 3 Nov 2023
Viewed by 1617
Abstract
Pompe disease (PD), also defined as acid maltase deficiency, is a rare autosomal recessive disease that causes glycogen accumulation due to a deficiency of the lysosomal enzyme acid α-glucosidase. An excessive amount of undisposed glycogen causes progressive muscle weakness throughout the body. It [...] Read more.
Pompe disease (PD), also defined as acid maltase deficiency, is a rare autosomal recessive disease that causes glycogen accumulation due to a deficiency of the lysosomal enzyme acid α-glucosidase. An excessive amount of undisposed glycogen causes progressive muscle weakness throughout the body. It particularly affects skeletal muscles and the nervous system, especially in the late-onset phase. Here, we present a clinical case of late-onset PD (LOPD) with normal CK (creatinine kinase) values treated after a misdiagnosis of demyelinating motor polyneuropathy and chronic inflammatory neuropathy. The suspicion of possible fibromyalgia induced the patient to seek a rheumatology consultation, and the investigations performed led to the diagnosis of PD. The patient was investigated for genetic and enzymatic studies. PD was diagnosed using the α-glucosidase assay on DBS. In LOPD, clinical manifestations, such as muscle weakness, exercise intolerance, myalgia, or even high hyperCKemia, often appear as nonspecific and may mimic a wide variety of other muscle disorders, such as limb muscle dystrophies, congenital, metabolic, or inflammatory myopathies. In our case, the patient had CK values in the normal range but with continued complaints typical of PD. An analysis of enzyme activity revealed a pathologic value, and genetic analysis identified the c.-32-13T>G mutation in homozygosis. The association of the pathological enzyme value and mutation in homozygosity with LOPD led to a familial segregation study. Our results contribute to the characterization of PD in Italy and support the importance of rheumatologic attention. This suggests further studies are needed to define the broad clinical and pathological spectrum observed in this disease. Full article
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