The Inflammation in the Cytopathology of Patients With Mucopolysaccharidoses- Immunomodulatory Drugs as an Approach to Therapy

CRISPR/nCas9-Edited CD34+ Cells Rescue Mucopolysaccharidosis IVA Fibroblasts Phenotype

Mucopolysaccharidosis (MPS) IVA is a bone-affecting lysosomal storage disease (LSD) caused by impaired degradation of the glycosaminoglycans (GAGs) keratan sulfate (KS) and chondroitin 6-sulfate (C6S) due to deficient N-acetylgalactosamine-6-sulfatase (GALNS) enzyme activity. Previously, we successfully developed and validated a CRISPR/nCas9-based gene therapy (GT) to insert an expression cassette at the AAVS1 and ROSA26 loci in human MPS IVA fibroblasts and MPS IVA mice, respectively. In this study, we have extended our approach to evaluate the effectiveness of our CRISPR/nCas9-based GT in editing human CD34+ cells to mediate cross-correction of MPS IVA fibroblasts. CD34+ cells were electroporated with the CRISPR/nCas9 system, targeting the AAVS1 locus. The nCas9-mediated on-target donor template insertion, and the stemness of the CRISPR/nCas-edited CD34+ cells was evaluated. Additionally, MPS IVA fibroblasts were co-cultured with CRISPR/nCas-edited CD34+ cells to assess cross-correction. CRISPR/nCas9-based gene editing did not affect the stemness of CD34+ cells but did lead to supraphysiological levels of the GALNS enzyme. Upon co-culture, MPS IVA fibroblasts displayed a significant increase in the GALNS enzyme activity along with lysosomal mass reduction, pro-oxidant profile amelioration, mitochondrial mass recovery, and pro-apoptotic and pro-inflammatory profile improvement. These results show the potential of our CRISPR/nCas9-based GT to edit CD34+ cells to mediate cross-correction.

Single-cell RNA sequencing reveals important role of monocytes and macrophages during mucopolysaccharidosis treatment

Mucopolysaccharidosis (MPS) encompasses a heterogeneous group of lysosomal storage diseases resulting from mutations in genes encoding lysosomal enzymes responsible for the degradation of mucopolysaccharides, also known as glycosaminoglycans (GAGs). Current therapeutic strategies for MPS include hematopoietic stem cell transplantation (HSCT), enzyme replacement therapy (ERT), and symptomatic therapy. This study investigated dynamic changes in MPS type II (MPS-II) through genomic and single-cell sequencing in a patient undergoing ERT. Analysis of peripheral blood mononuclear cells (PBMCs) from one MPS-II patient of 10 year old at different disease stages through scRNA-seq identified various immune cell types, including natural killer (NK) cells, NKT cells, CD4 + and CD8 + T cells, CD14 + and CD16 + monocytes, and B cells. Monocytes and macrophages were significantly reduced during the severe stage of MPS-II but increased during the recovery stage following ERT. Notably, monocyte subtype mono3 was exclusively expressed in the severe stage, while mono1_2, a subtype of mono1, was absent during the severe stage and exhibited distinct biological functions. These findings suggest that monocytes and macrophages play critical roles in the pathogenesis of MPS-II and in the response to ERT. Pseudotime, Gene Ontology, and cell-communication analyses revealed unique functions for the different cellular subtypes. Notably, key molecules mediating cellular interactions during ERT in MPS-II included CXCR3, PF4, APP, and C5AR1 in macrophages, RPS19 in T cells, HLA-DPB1 in B cells, ADRB2 in NK cells, and IL1B, C5AR1, RPS19, and TNFSF13B in monocytes. Overall, integrative analysis delineated the expression dynamics of various cell types and identified mutations in MPS-II, providing a comprehensive atlas of transcriptional programs, cellular characterizations, and genomic variation profiles in MPS-II. This dataset, along with advanced integrative analysis, represents a valuable resource for the discovery of drug targets and the improvement of therapeutic strategies for MPS-II.

Oral trehalose improves histological and behavior symptoms of mucopolysaccharidosis type II in iduronate 2-sulfatase deficient mice

Mucopolysaccharidosis type II (MPS II) is caused by a deficiency in iduronate-2-sulfatase (Ids), an enzyme that catabolizes glycosaminoglycan (GAG). Ids insufficiency results in the accumulation of GAG in various organs, ultimately resulting in multisystemic disease. Trehalose, a non-reducing disaccharide, has shown protective effects against various diseases. However, its potential utility through oral administration in MPS II has not yet been explored. In the present study, to investigate the efficacy of oral trehalose in Ids-knock-out (KO) mice, Ids-KO and wild type (WT) mice were treated with 2% trehalose dissolved in distilled water ad libitum for 24 weeks. Histological analysis revealed that almost all tissues from Ids-KO mice exhibited abnormal changes, including large vacuolization, inflammatory cell infiltration, and GAG deposition. However, oral administration of trehalose significantly suppressed GAG levels, vacuolization, inflammation and apoptosis in the spleen and brain. Additionally, oral trehalose considerably improved cognitive functions, such as short-term spatial learning and working memory, alongside limited improvements in walking capacity in Ids-KO mice. These results suggest that oral trehalose can reduce GAG accumulation, vacuolization and the number of apoptotic and inflammatory cells in pathological tissues including the brain, ultimately considerably improving spontaneous alteration behavior and could be a promising treatment option for MPS II.

Parental perception of treatment options for mucopolysaccharidosis: a survey to bridge the gap for personalized medicine

BACKGROUND

Mucopolysaccharidosis (MPS) are a group of lysosomal storage diseases with substantial unmet medical needs-for both patients and caregivers. Approved therapies are limited, and the perception of investigative ones remains enigmatic.

METHOD

Using an innovative survey concept based on the discrete choice experiment method (DEC) with neuronopathic and non-neuronopathic patient scenarios, we aimed to evaluate how parents of children with MPS perceive different approved and innovative therapies. The questionnaire was distributed via patient organizations in Germany, Switzerland, and Austria.

RESULTS

Most likely parents would choose an approach to repurposed treatments for their child (neuronopathic: 82%, 14/17 and non-neuronopathic: 94%, 16/17), followed by enzyme replacement therapy (ERT, both 88%, 15/17), hematopoietic stem cell therapy (HSCT, 70%, 12/17 and 76%, 13/17), and finally gene therapy (GT, 58%, 10/17 and 53%, 9/17). The general attitudes strongly influenced decision-making regarding treatment options. While over 80% of respondents who held a positive attitude toward ERT, HSCT, and ITTs indicated they would opt for these therapies in both neuronopathic and non-neuronopathic cases, only about half of the parents with a favorable general view of gene therapy (GT) expressed a positive perception of its likelihood as a treatment option. Furthermore, most parents found mild infections, injection site reactions (ISRs), hypertonia, and treatment-related hospitalizations acceptable and indicated patient organizations as their main source of information.

CONCLUSIONS

This study provides an innovative survey method, thereby offering the rationale for a quantitative risk-benefit model and the importance of patient and caregiver-centered information dissemination, especially for innovative therapies.

Development of a novel tool for individual treatment trials in mucopolysaccharidosis

Mucopolysaccharidosis (MPS) encompasses a group of genetic lysosomal storage disorders, linked to reduced life expectancy and a significant lack of effective treatment options. Immunomodulatory drugs could have the potential to be a relevant medical approach, as the accumulation of undegraded substances initiates an innate immune response, which leads to inflammation and clinical deterioration. However, immunomodulators are not licensed for this indication. Consequently, we aim to provide evidence advocating fast access to innovative individual treatment trials (ITTs) with immunomodulatory drugs and high-quality evaluation of drug effects by implementing a risk-benefit model tailored for MPS. The iterative methodology of our novel decision analysis framework (DAF) involves three key steps: (i) literature review on promising treatment targets and immunomodulators in MPS; (ii) quantitative risk-benefit assessment (RBA) of selected molecules; (iii) assigning phenotypic profiles and quantitative evaluations. The results facilitate a personalized application of the model and are based on published evidence as well as interdisciplinary experts' consensus and patient perspectives. Four promising immunomodulators have been identified: adalimumab, abatacept, anakinra, and cladribine. An improvement in mobility is most likely with adalimumab, while anakinra is anticipated as a treatment of choice for neuronopathic MPS patients. Nevertheless, a comprehensive RBA should always be completed on an individual basis. Our evidence-based DAF tool for ITTs directly addresses the substantial unmet medical need in MPS and characterizes an initial stride toward precision medicine with immunomodulators.

Evaluation of etanercept (a tumor necrosis factor alpha inhibitor) as an effective treatment for joint disease in mucopolysaccharidosis type I. A case report with whole-body magnetic resonance imaging

Summary

A 12-year-old girl with mucopolysaccharidosis (MPS) type I (Gurler-Scheie syndrome, Q70X/del C683 of the IDUA gene in the compound heterozygous state) regularly received enzyme replacement therapy (laronidase) since the preclinical stage (6 months old) due to positive family history, and started etanercept treatment due to progression of joint pain and decreasing capability to walk. The patient had a significant reduction of pain in the joints and an expansion of daily physical activity without adverse events. A decrease in bone marrow edema without foci progression compared to baseline assessment was observed in the whole-body MRI.During the treatment (baseline/6 months/12 months) the following was observed: childhood health assessment questionnaire (CHAQ) index of 1.88/2.13/1.63 points; patient's pediatric quality of life inventory (PedsQL) of 37/30/31 points; parental PedsQL of 26/27/34 points; and patient's pain visual-analog scale (VAS) of 75/45/40, with no VAS recorded for the mother. Juvenile arthritis functional assessment report (JAFAR) scores of 35/34/8 points were observed. A significant reduction in the taking of NSAIDs was observed. In the second half of the year, the nasal breathing became normal, and remission in chronic rhinitis and adenoiditis was achieved (no infection episodes) without otitis episodes.

Conclusion

Etanercept in mucopolysaccharidosis type 1 is safe and well tolerated. The reduction of joint pain and increased walking capacity were observed. A decreased number of respiratory infection episodes and nasal breathing improvement were noted during the treatment. The observation shows the role of inflammation in the different aspects of MPS. Further investigations on immune system dysregulation in patients with MPS I are needed. Additional studies on the efficacy and safety of anti-rheumatic biological drugs in patients with MPSI are required.

Molecular Mechanisms in Pathophysiology of Mucopolysaccharidosis and Prospects for Innovative Therapy

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.

Iron oxide-coupled CRISPR-nCas9-based genome editing assessment in mucopolysaccharidosis IVA mice

Mucopolysaccharidosis (MPS) IVA is a lysosomal storage disorder caused by mutations in the GALNS gene that leads to the lysosomal accumulation of keratan sulfate (KS) and chondroitin 6-sulfate, causing skeletal dysplasia and cardiopulmonary complications. Current enzyme replacement therapy does not impact the bone manifestation of the disease, supporting that new therapeutic alternatives are required. We previously demonstrated the suitability of the CRISPR-nCas9 system to rescue the phenotype of human MPS IVA fibroblasts using iron oxide nanoparticles (IONPs) as non-viral vectors. Here, we have extended this strategy to an MPS IVA mouse model by inserting the human GALNS cDNA into the ROSA26 locus. The results showed increased GALNS activity, mono-KS reduction, partial recovery of the bone pathology, and non-IONPs-related toxicity or antibody-mediated immune response activation. This study provides, for the first time, in vivo evidence of the potential of a CRISPR-nCas9-based gene therapy strategy for treating MPS IVA using non-viral vectors as carriers.

Molecular Trojan Horses for treating lysosomal storage diseases

Lysosomal storage diseases (LSDs) are caused by monogenic mutations in genes encoding for proteins related to the lysosomal function. Lysosome plays critical roles in molecule degradation and cell signaling through interplay with many other cell organelles, such as mitochondria, endoplasmic reticulum, and peroxisomes. Even though several strategies (i.e., protein replacement and gene therapy) have been attempted for LSDs with promising results, there are still some challenges when hard-to-treat tissues such as bone (i.e., cartilages, ligaments, meniscus, etc.), the central nervous system (mostly neurons), and the eye (i.e., cornea, retina) are affected. Consistently, searching for novel strategies to reach those tissues remains a priority. Molecular Trojan Horses have been well-recognized as a potential alternative in several pathological scenarios for drug delivery, including LSDs. Even though molecular Trojan Horses refer to genetically engineered proteins to overcome the blood-brain barrier, such strategy can be extended to strategies able to transport and deliver drugs to specific tissues or cells using cell-penetrating peptides, monoclonal antibodies, vesicles, extracellular vesicles, and patient-derived cells. Only some of those platforms have been attempted in LSDs. In this paper, we review the most recent efforts to develop molecular Trojan Horses and discuss how this strategy could be implemented to enhance the current efficacy of strategies such as protein replacement and gene therapy in the context of LSDs.

Disease pathology signatures in a mouse model of Mucopolysaccharidosis type IIIB

Mucopolysaccharidosis type IIIB (MPS IIIB) is a rare and devastating childhood-onset lysosomal storage disease caused by complete loss of function of the lysosomal hydrolase α-N-acetylglucosaminidase. The lack of functional enzyme in MPS IIIB patients leads to the progressive accumulation of heparan sulfate throughout the body and triggers a cascade of neuroinflammatory and other biochemical processes ultimately resulting in severe mental impairment and early death in adolescence or young adulthood. The low prevalence and severity of the disease has necessitated the use of animal models to improve our knowledge of the pathophysiology and for the development of therapeutic treatments. In this study, we took a systematic approach to characterizing a classical mouse model of MPS IIIB. Using a series of histological, biochemical, proteomic and behavioral assays, we tested MPS IIIB mice at two stages: during the pre-symptomatic and early symptomatic phases of disease development, in order to validate previously described phenotypes, explore new mechanisms of disease pathology and uncover biomarkers for MPS IIIB. Along with previous findings, this study helps provide a deeper understanding of the pathology landscape of this rare disease with high unmet medical need and serves as an important resource to the scientific community.

An Innovative Tool for Evidence-Based, Personalized Treatment Trials in Mucopolysaccharidosis

Mucopolysaccharidosis (MPS) is a group of rare metabolic diseases associated with reduced life expectancy and a substantial unmet medical need. Immunomodulatory drugs could be a relevant treatment approach for MPS patients, although they are not licensed for this population. Therefore, we aim to provide evidence justifying fast access to innovative individual treatment trials (ITTs) with immunomodulators and a high-quality evaluation of drug effects by implementing a risk-benefit model for MPS. The iterative methodology of our developed decision analysis framework (DAF) consists of the following steps: (i) a comprehensive literature analysis on promising treatment targets and immunomodulators for MPS; (ii) a quantitative risk-benefit assessment (RBA) of selected molecules; and (iii) allocation phenotypic profiles and a quantitative assessment. These steps allow for the personalized use of the model and are in accordance with expert and patient representatives. The following four promising immunomodulators were identified: adalimumab, abatacept, anakinra, and cladribine. An improvement in mobility is most likely with adalimumab, while anakinra might be the treatment of choice for patients with neurocognitive involvement. Nevertheless, a RBA should always be completed on an individual basis. Our evidence-based DAF model for ITTs directly addresses the substantial unmet medical need in MPS and characterizes a first approach toward precision medicine with immunomodulatory drugs.

Individual Treatment Trials—Do Experts Know and Use This Option to Improve the Treatability of Mucopolysaccharidosis?

Mucopolysaccharidoses (MPS) are a group of rare, heterogeneous, lysosomal storage disorders. Patients show a broad spectrum of clinical features with a substantial unmet medical need. Individual treatment trials (ITTs) might be a valid, time- and cost-efficient way to facilitate personalized medicine in the sense of drug repurposing in MPS. However, this treatment option has so far hardly been used—at least hardly been reported or published. Therefore, we aimed to investigate the awareness and utilization of ITTs among MPS clinicians, as well as the potential challenges and innovative approaches to overcome key hurdles, by using an international expert survey on ITTs, namely, ESITT. Although 74% (20/27) were familiar with the concept of ITTs, only 37% (10/27) ever used it, and subsequently only 15% (2/16) published their results. The indicated hurdles of ITTs in MPS were mainly the lack of time and know-how. An evidence-based tool, which provides resources and expertise needed for high-quality ITTs, was highly appreciated by the vast majority (89%; 23/26). The ESITT highlights a serious deficiency of ITT implementation in MPS—a promising option to improve its treatability. Furthermore, we discuss the challenges and innovative approaches to overcome key barriers to ITTs in MPS.

Mucopolysaccharidoses: Cellular Consequences of Glycosaminoglycans Accumulation and Potential Targets

Mucopolysaccharidoses (MPSs) constitute a heterogeneous group of lysosomal storage disorders characterized by the lysosomal accumulation of glycosaminoglycans (GAGs). Although lysosomal dysfunction is mainly affected, several cellular organelles such as mitochondria, endoplasmic reticulum, Golgi apparatus, and their related process are also impaired, leading to the activation of pathophysiological cascades. While supplying missing enzymes is the mainstream for the treatment of MPS, including enzyme replacement therapy (ERT), hematopoietic stem cell transplantation (HSCT), or gene therapy (GT), the use of modulators available to restore affected organelles for recovering cell homeostasis may be a simultaneous approach. This review summarizes the current knowledge about the cellular consequences of the lysosomal GAGs accumulation and discusses the use of potential modulators that can reestablish normal cell function beyond ERT-, HSCT-, or GT-based alternatives.

Diagnosis and Emerging Treatment Strategies for Mucopolysaccharidosis VII (Sly Syndrome)

Mucopolysaccharidosis VII (MPS VII, Sly syndrome) is an ultra-rare lysosomal disease caused by a deficiency of the enzyme β-glucuronidase (GUS). The diagnosis is suspected based on a range of symptoms that are common to many other MPS types, and it is confirmed through biochemical and molecular studies. Besides supportive treatment, current and emerging treatments include enzyme replacement therapy, hematopoietic stem cell transplantation, and gene therapy. This review summarizes the clinical manifestations, diagnosis, and emerging treatments for MPS VII.