Accumulation Of Glycosaminoglycans Research Articles

Lysosomal storage diseases. Sphingolipidoses – leukodystrophy

Lysosomal storage diseases. Sphingolipidoses – leukodystrophy

Widespread Vascularization and Correlation of Glycosaminoglycan Accumulation to Tendon Pain in Human Plantar Fascia Tendinopathy.

Plantar fasciitis is a painful tendinous condition (tendinopathy) with a high prevalence in athletes. While a healthy tendon has limited blood flow, ultrasound has indicated elevated blood flow in tendinopathy, but it is unknown if this is related to a de facto increase in the tendon vasculature. Likewise, an accumulation of glycosaminoglycans (GAGs) is observed in tendinopathy, but its relationship to clinical pain is unknown. To explore to what extent vascularization, inflammation, and fat infiltration were present in patients with plantar fasciitis and if they were related to clinical symptoms. Descriptive laboratory study. Biopsy specimens from tendinopathic plantar fascia tissue were obtained per-operatively from both the primary site of tendon pain and tissue swelling ("proximal") and a region that appeared macroscopically healthy at 1 to 2 cm away from the primary site ("distal") in 22 patients. Biopsy specimens were examined with immunofluorescence for markers of blood vessels, tissue cell density, fat infiltration, and macrophage level. In addition, pain during the first step in the morning (registered during an earlier study) was correlated with the content of collagen and GAGs in tissue. High vascularization (and cellularity) was present in both the proximal (0.89%) and the distal (0.96%) plantar fascia samples, whereas inconsistent but not significantly different fat infiltration and macrophage levels were observed. The collagen content was similar in the 2 plantar fascia regions, whereas the GAG content was higher in the proximal region (3.2% in proximal and 2.8% in distal; P = .027). The GAG content in the proximal region was positively correlated with the subjective morning pain score in the patients with tendinopathy (n = 17). In patients with plantar fasciitis, marked tissue vascularization was present in both the painful focal region and a neighboring nonsymptomatic area. In contrast, the accumulation of hydrophilic GAGs was greater in the symptomatic region and was positively correlated with increased clinical pain levels in daily life. The accumulation of GAGs in tissue rather than the extent of vascularization appears to be linked with the clinical degree of pain symptoms of the disease.

Molecular therapy and nucleic acid adeno-associated virus-based gene therapy delivering combinations of two growth-associated genes to MPS IVA mice

Mucopolysaccharidosis type IVA (MPS IVA) is caused by a deficiency of the N-acetylgalactosamine-6-sulfate sulfatase (GALNS) enzyme responsible for the degradation of specific glycosaminoglycans (GAGs). The progressive accumulation of GAGs leads to various skeletal abnormalities (short stature, hypoplasia, tracheal obstruction) and several symptoms in other organs. To date, no treatment is effective for patients with bone abnormalities. To improve bone pathology, we propose a novel combination treatment with the AAV vectors expressing GALNS enzyme and a C-type natriuretic peptide (CNP; NPPC gene) as a growth-promoting agent for MPS IVA. In this study, an MPS IVA mouse model was treated with an AAV vector expressing GALNS combined with another AAV vector expressing NPPC gene, followed for 12 weeks. After the combination therapy, bone growth in mice was induced with increased enzyme activity in tissues (bone, liver, heart, lung) and plasma. Moreover, there were significant changes in bone morphology in CNP-treated mice with increased CNP activity in plasma. Delivering combinations of CNP and GALNS gene therapies enhanced bone growth in MPS IVA mice more than in GALNS gene therapy alone. Enzyme expression therapy alone fails to reach the bone growth region; our results indicate that combining it with CNP offers a potential alternative.

Mature neurons from iPSCs unveil neurodegeneration-related pathways in mucopolysaccharidosis type II: GSK-3β inhibition for therapeutic potential

Mucopolysaccharidosis (MPS) type II is caused by a deficiency of iduronate-2-sulfatase and is characterized by the accumulation of glycosaminoglycans (GAGs). Without effective therapy, the severe form of MPS II causes progressive neurodegeneration and death. This study generated multiple clones of induced pluripotent stem cells (iPSCs) and their isogenic controls (ISO) from four patients with MPS II neurodegeneration. MPS II-iPSCs were successfully differentiated into cortical neurons with characteristic biochemical and cellular phenotypes, including axonal beadings positive for phosphorylated tau, and unique electrophysiological abnormalities, which were mostly rescued in ISO-iPSC-derived neurons. RNA sequencing analysis uncovered dysregulation in three major signaling pathways, including Wnt/β-catenin, p38 MAP kinase, and calcium pathways, in mature MPS II neurons. Further mechanistic characterization indicated that the dysregulation in calcium signaling led to an elevated intracellular calcium level, which might be linked to compromised survival of neurons. Based on these dysregulated pathways, several related chemicals and drugs were tested using this mature MPS II neuron-based platform and a small-molecule glycogen synthase kinase-3β inhibitor was found to significantly rescue neuronal survival, neurite morphology, and electrophysiological abnormalities in MPS II neurons. Our results underscore that the MPS II-iPSC-based platform significantly contributes to unraveling the mechanisms underlying the degeneration and death of MPS II neurons and assessing potential drug candidates. Furthermore, the study revealed that targeting the specific dysregulation of signaling pathways downstream of GAG accumulation in MPS II neurons with a well-characterized drug could potentially ameliorate neuronal degeneration.

On the Mechanism of the Lysosomal Enzyme Iduronate‐2‐sulfatase. A Multiscale Approach

AbstractIduronate‐2‐sulfatase (IDS) is a Ca2+‐dependent enzyme belonging to the family of sulfatases that catalyzes the hydrolysis of sulphurylated glycosaminoglycans (GAGs), like dermatan and heparan sulphate. Its deficiency or modification leads to the accumulation of GAGs in the human body and to the occurrence of severe conditions, such as Hunter disease, or Mucopolysaccharidosis type II. Due to its involvement in this syndrome, it is of interest to understand the action mechanism of the enzyme to design new drugs for more efficient medical strategies. In the present work, we carried out a detailed multiscale modelling‐based investigation, adopting molecular dynamics simulation (MDs) and QM/MM calculations to study the enzyme‐dermatan sulfate interactions and to investigate the reaction mechanism of IDS. The analysis of molecular dynamics trajectories helped to shed light on the contribution of the individual residues of the active site in the recognition of dermatan sulfate. The role of FGly84 and His229, investigated in both neutral and protonated states in the case of the latter, is highlighted for the binding of the substrate. QM/MM calculations demonstrated that the reaction mechanism is a two‐steps process occurring via a sulphurylation‐desulphurylation mechanism where the FGly84 first attacks the sulphate group of the dermatan sulphate (DS), and later is desulphurylated.

Inhibitors of dermatan sulfate epimerase 1 decreased accumulation of glycosaminoglycans in mucopolysaccharidosis type I fibroblasts.

Genetic deficiency of alpha-L-iduronidase causes mucopolysaccharidosis type I (MPS-I) disease, due to accumulation of glycosaminoglycans (GAGs) including chondroitin/dermatan sulfate (CS/DS) and heparan sulfate (HS) in cells. Currently, patients are treated by infusion of recombinant iduronidase or by hematopoietic stem cell transplantation. An alternative approach is to reduce the L-iduronidase substrate, through limiting the biosynthesis of iduronic acid. Our earlier study demonstrated that ebselen attenuated GAGs accumulation in MPS-I cells, through inhibiting iduronic acid producing enzymes. However, ebselen has multiple pharmacological effects, which prevents its application for MPS-I. Thus, we continued the study by looking for novel inhibitors of dermatan sulfate epimerase 1 (DS-epi1), the main responsible enzyme for production of iduronic acid in CS/DS chains. Based on virtual screening of chemicals towards chondroitinase AC, we constructed a library with 1,064 compounds that were tested for DS-epi1 inhibition. Seventeen compounds were identified to be able to inhibit 27%-86% of DS-epi1 activity at 10μM. Two compounds were selected for further investigation based on the structure properties. The results show that both inhibitors had a comparable level in inhibition of DS-epi1while they had negligible effect on HS epimerase. The two inhibitors were able to reduce iduronic acid biosynthesis in CS/DS and GAG accumulation in WT and MPS-I fibroblasts. Docking of the inhibitors into DS-epi1 structure shows high affinity binding of both compounds to the active site. The collected data indicate that these hit compounds may be further elaborated to a potential lead drug used for attenuation of GAGs accumulation in MPS-I patients.

Clinical investigator perspectives on patient outcomes in children with neuronopathic mucopolysaccharidosis II during intrathecal idursulfase-IT treatment

BackgroundMucopolysaccharidosis II (MPS II) is a rare lysosomal storage disease characterized by iduronate-2-sulfatase gene (IDS) deficiency and downstream glycosaminoglycan accumulation. Two-thirds of patients present with neuronopathic disease and evaluating cognitive function in these patients is challenging owing to limitations of currently available tests. During the clinical development of intrathecal idursulfase (idursulfase-IT), regulatory authorities requested qualitative data to further understand the neurocognitive changes observed by the investigators through the clinical trials.ResultsThis qualitative study consisted of semi-structured interviews with all nine of the principal investigators who participated in the idursulfase-IT phase 2/3 (NCT02055118) and extension (NCT02412787) trials. These investigators enrolled the 56 patients with neuronopathic MPS II who qualified for the extension phase of the trial. The investigators were asked to rate the disease status of their patients. Of the 56 patients, 49 (88%) were rated as having disease that was improved/improving, stabilized or slowing progression compared with the expected outcomes with no treatment. Three patients were rated as worsening, while the remaining four patients were considered to have slowing progression or worsening disease. Similar results were demonstrated for patients aged from 3 to under 6 years at baseline, with 33 of 39 patients (85%) rated as having disease that was improved/improving, stabilized or slowing progression. Of the seven patients rated with slowing progression/worsening or worsening disease, five of them had an IDS variant other than missense, while two had a missense class variant. All the assigned improved/improving ratings were in patients receiving idursulfase-IT from the start of the phase 2/3 trial. Moreover, patients under 3 years of age at baseline were all rated as either improved/improving or stabilized disease. In a blinded review of patient profiles, investigators were requested to assign a disease status rating to 18 patients with large IDS deletions; 67% of these patients were rated as improved/improving or stabilized disease.ConclusionsThis qualitative analysis provides a snapshot of clinicians’ considerations when evaluating treatment in patients with neuronopathic MPS II, compared with the expected decline in cognitive function in the absence of treatment. The results highlight the importance of robust assessment tools in treatment evaluation.

Disturbances in mitochondrial bioenergetics and control quality and unbalanced redox homeostasis in the liver of a mouse model of mucopolysaccharidosis type II.

Mucopolysaccharidosis type II (MPS II; Hunter syndrome) is a lysosomal storage disease caused by mutations in the gene encoding the enzyme iduronate 2-sulfatase (IDS) and biochemically characterized by the accumulation of glycosaminoglycans (GAGs) in different tissues. It is a multisystemic disorder that presents liver abnormalities, the pathophysiology of which is not yet established. In the present study, we evaluated bioenergetics, redox homeostasis, and mitochondrial dynamics in the liver of 6-month-old MPS II mice (IDS-). Our findings show a decrease in the activity of α-ketoglutarate dehydrogenase and an increase in the activities of succinate dehydrogenase and malate dehydrogenase. The activity of mitochondrial complex I was also increased whereas the other complex activities were not affected. In contrast, mitochondrial respiration, membrane potential, ATP production, and calcium retention capacity were not altered. Furthermore, malondialdehyde levels and 2',7'-dichlorofluorescein oxidation were increased in the liver of MPS II mice, indicating lipid peroxidation and increased ROS levels, respectively. Sulfhydryl and reduced glutathione levels, as well as glutathione S-transferase, glutathione peroxidase (GPx), superoxide dismutase, and catalase activities were also increased. Finally, the levels of proteins involved in mitochondrial mass and dynamics were decreased in knockout mice liver. Taken together, these data suggest that alterations in energy metabolism, redox homeostasis, and mitochondrial dynamics can be involved in the pathophysiology of liver abnormalities observed in MPS II.

The Role of Fibrogenesis and Extracellular Matrix Proteins in the Pathogenesis of Graves' Ophthalmopathy.

Graves' ophthalmopathy (GO), or thyroid eye disease (TED), is the most frequent extrathyroidal manifestation of Graves' disease (GD). Inflammation and subsequent aberrant tissue remodeling with fibrosis are important pathogenesis. There are many proposed mechanisms and molecular pathways contributing to tissue remodeling and fibrosis in GO, including adipogenesis, fibroblast proliferation and myofibroblasts differentiation, oxidative stress, endoplasmic reticulum (ER) stress, hyaluronan (HA) and glycosaminoglycans (GAGs) accumulation in the extracellular matrix (ECM) and new concepts of epigenetics modification, such as histone modification, DNA methylation, non-coding RNAs, and gut microbiome. This review summarizes the current understanding of ECM proteins and associated tissue remodeling in the pathogenesis and potential mediators for the treatment of GO.

Open-label, single-center, clinical study evaluating the safety, tolerability and clinical effects of pentosan polysulfate sodium in subjects with mucopolysaccharidosis I.

Lysosomal enzyme deficiency in mucopolysaccharidosis (MPS) I results in glycosaminoglycan (GAG) accumulation leading to pain and limited physical function. Disease-modifying treatments for MPS I, enzyme replacement, and hematopoietic stem cell therapy (HSCT), do not completely resolve MPS I symptoms, particularly skeletal manifestations. The GAG reduction, anti-inflammatory, analgesic, and tissue remodeling properties of pentosan polysulfate sodium (PPS) may provide disease-modifying treatment for musculoskeletal symptoms and joint inflammation in MPS I following ERT and/or HSCT. The safety and efficacy of PPS were evaluated in four subjects with MPS I aged 14-19 years, previously treated with ERT and/or HSCT. Subjects received doses of 0.75 mg/kg or 1.5 mg/kg PPS via subcutaneous injections weekly for 12 weeks, then every 2 weeks for up to 72 weeks. PPS was well tolerated at both doses with no serious adverse events. MPS I GAG fragment (UA-HNAc [1S]) levels decreased at 73 weeks. Cartilage degradation biomarkers serum C-telopeptide of crosslinked collagen (CTX) type I (CTX-I) and type II (CTX-II) and urine CTX-II decreased in all subjects through 73 weeks. PROMIS scores for pain interference, pain behavior, and fatigue decreased in all subjects through 73 weeks. Physical function, measured by walking distance and dominant hand function, improved at 49 and 73 weeks. Decreased GAG fragments and cartilage degradation biomarkers, and positive PROMIS outcomes support continued study of PPS as a potential disease-modifying treatment for MPS I with improved pain and function outcomes.

Unveiling Modern Strategies for Diagnosing and Treating Grave Orbitopathy

Graves' Orbitopathy (GO), also known as thyroid eye disease or thyroid-associated orbitopathy is characterized by inflammation, ocular muscle hypertrophy, adipogenesis, and oedema (due to glycosaminoglycan accumulation). This condition leads to remodeling, tissue expansion, and/or fibrosis within the fibroadipose tissue or extraocular muscles of the orbit. GO manifests as an extrathyroidal aspect of autoimmune thyroid diseases in both Grave's disease (GD) and Hashimoto's thyroiditis.
 The pathophysiological foundation of GO entails the infiltration of B cells, T cells, and CD34+ fibroblasts in the orbit. B cells generate IGF (insulin-like growth factor), wherein IGF and TRab (Thyroid-Receptor antibodies) stimulate the IGF receptor complex and thyrotropin receptor (respectively) on the surface of CD34+ cells which triggers orbital tissue expansion, orbital protrusion, optic nerve compression, and eyeball displacement, resulting in exophthalmos.
 GO progress through an active phase (characterized by inflammation with visible manifestations), followed by a plateau phase (stabilization of GO manifestations), and a gradual resolution of distinctive residual signs and symptoms (inactive phase). This entire process spans between 18-24 months in untreated patients, where disease manifestations significantly depend on the phase during which the disease is identified.
 GO therapy is intended to shorten the active phase and supress its residual eye manifestations during the inactive phase. In general, GO therapy is categorized into general and disease severity-specific approaches.
 GO therapy often falls short of providing satisfactory results, prompting need of surgery to address lingering clinical manifestations. This review presents the latest insights into the pathogenesis and treatment of GO for better management and outcomes.

MiRNA Regulation of Cell Phenotype and Parietal Remodeling in Atherosclerotic and Non-Atherosclerotic Aortic Aneurysms: Differences and Similarities.

Aortic aneurysms are a serious health concern as their rupture leads to high morbidity and mortality. Abdominal aortic aneurysms (AAAs) and thoracic aortic aneurysms (TAAs) exhibit differences and similarities in their pathophysiological and pathogenetic features. AAA is a multifactorial disease, mainly associated with atherosclerosis, characterized by a relevant inflammatory response and calcification. TAA is rarely associated with atherosclerosis and in some cases is associated with genetic mutations such as Marfan syndrome (MFS) and bicuspid aortic valve (BAV). MFS-related and non-genetic or sporadic TAA share aortic degeneration with endothelial-to-mesenchymal transition (End-Mt) and fibrosis, whereas in BAV TAA, aortic degeneration with calcification prevails. microRNA (miRNAs) contribute to the regulation of aneurysmatic aortic remodeling. miRNAs are a class of non-coding RNAs, which post-transcriptionally regulate gene expression. In this review, we report the involvement of deregulated miRNAs in the different aortic remodeling characterizing AAAs and TAAs. In AAA, miRNA deregulation appears to be involved in parietal inflammatory response, smooth muscle cell (SMC) apoptosis and aortic wall calcification. In sporadic and MFS-related TAA, miRNA deregulation promotes End-Mt, SMC myofibroblastic phenotypic switching and fibrosis with glycosaminoglycan accumulation. In BAV TAA, miRNA deregulation sustains aortic calcification. Those differences may support the development of more personalized therapeutic approaches.

Fabrication of stem cell heterospheroids with sustained-release chitosan and poly(lactic-co-glycolic acid) microspheres to guide cell fate toward chondrogenic differentiation

Mesenchymal stem cell (MSC)-based therapies show great potential in treating various diseases. However, control of the fate of injected cells needs to be improved. In this work, we developed an efficient methodology for modulating chondrogenic differentiation of MSCs. We fabricated heterospheroids with two sustained-release depots, a quaternized chitosan microsphere (QCS-MP) and a poly (lactic-co-glycolic acid) microsphere (PLGA-MP). The results show that heterospheroids composed of 1 × 104 to 5 × 104 MSCs formed rapidly during incubation in methylcellulose medium and maintained high cell viability in long-term culture. The MPs were uniformly distributed in the heterospheroids, as shown by confocal laser scanning microscopy. Incorporation of transforming growth factor beta 3 into QCS-MPs and of dexamethasone into PLGA-MPs significantly promoted the expression of chondrogenic genes and high accumulation of glycosaminoglycan in heterospheroids. Changes in crucial metabolites in the dual drug depot–engineered heterospheroids were also evaluated using 1H NMR-based metabolomics analysis to verify their successful chondrogenic differentiation. Our heterospheroid fabrication platform could be used in tissue engineering to study the effects of various therapeutic agents on stem cell fate.

Evaluation of tendon and ligament microstructure and mechanical properties in a canine model of mucopolysaccharidosis I.

Mucopolysaccharidosis (MPS) I is a lysosomal storage disorder characterized by deficient alpha-l-iduronidase activity, leading to abnormal accumulation of glycosaminoglycans (GAGs) in cells and tissues. Synovial joint disease is prevalent and significantly reduces patient quality of life. There is a strong clinical need for improved treatment approaches that specifically target joint tissues; however, their development is hampered by poor understanding of underlying disease pathophysiology, including how pathological changes to component tissues contribute to overall joint dysfunction. Ligaments and tendons, in particular, have received very little attention, despite the critical roles of these tissues in joint stability and biomechanical function. The goal of this study was to leverage the naturally canine model to undertake functional and structural assessments of the anterior (cranial) cruciate ligament (CCL) and Achilles tendon in MPS I. Tissues were obtained postmortem from 12-month-old MPS I and control dogs and tested to failure in uniaxial tension. Both CCLs and Achilles tendons from MPS I animals exhibited significantly lower stiffness and failure properties compared to those from healthy controls. Histological examination revealed multiple pathological abnormalities, including collagen fiber disorganization, increased cellularity and vascularity, and elevated GAG content in both tissues. Clinically, animals exhibited mobility deficits, including abnormal gait, which was associated with hyperextensibility of the stifle and hock joints. These findings demonstrate that pathological changes to both ligaments and tendons contribute to abnormal joint function in MPS I, and suggest that effective clinical management of joint disease in patients should incorporate treatments targeting these tissues.

Identification of new variants in patients with mucopolysaccharidosis in consanguineous Iranian families.

Introduction: Mucopolysaccharidoses are a group of lysosomal storage disorders that include seven types that are classified based on the enzymes that are disrupted. Malfunction of these enzymes leads to the accumulation of glycosaminoglycans (GAGs) in various tissues. Due to genetic and clinical heterogeneity, diagnosing and distinguishing the different types is challenging. Genetic methods such as whole exome sequencing (WES) and Sanger sequencing are accurate methods for detecting pathogenic variants in patients. Methods: Thirty-two cases of mucopolysaccharidosis, predominantly from families with consanguineous marriages, were genetically examined. Out of these, fourteen cases underwent targeted sequencing, while the rest underwent WES. The results of WES were analyzed and the pathogenicity of the variants was examined using bioinformatics tools. In addition, a segregation analysis within families was carried out. Results: In most cases, a pathogenic or likely pathogenic variant was detected. Sixteen previously reported variants and six new variants were detected in the known IDS (c.458G>C, c.701del, c.920T>G), GNS (c.1430A>T), GALNS (c.1218_1221dup), and SGSH (c.149T>C) genes. Furthermore, we discovered a c.259G>C substitution in the NAGLU gene for the first time in three homozygous patients. This substitution was previously reported as heterozygous. Except for the variants related to the IDS gene, which were hemizygous, all the other variants were homozygous. Discussion: It appears that the high rate of consanguineous marriages in the families being studied has had a significant impact on the occurrence of this disease. Overall, these findings could expand the spectrum of pathogenic variants in mucopolysaccharidoses. Genetic methods, especially WES, are very accurate and can be used alone or in conjunction with other diagnostic methods for a more precise and rapid diagnosis of mucopolysaccharidoses. Additionally, they could be beneficial for family screening and disease prevention.

Effect of genistein and coenzyme Q10 in oxidative damage and mitochondrial membrane potential in an attenuated type II mucopolysaccharidosis cellular model.

Mucopolysaccharidosis type II (MPS II) is an inborn error of the metabolism resulting from several possible mutations in the gene coding for iduronate-2-sulfatase (IDS), which leads to a great clinical heterogeneity presented by these patients. Many studies demonstrate the involvement of oxidative stress in the pathogenesis of inborn errors of metabolism, and mitochondrial dysfunction and oxidative stress can be related since most of reactive oxygen species come from mitochondria. Cellular models have been used to study different diseases and are useful in biochemical research to investigate them in a new promising way. The aim of this study is to develop a heterozygous cellular model for MPS II and analyze parameters of oxidative stress and mitochondrial dysfunction and investigate the in vitro effect of genistein and coenzyme Q10 on these parameters for a better understanding of the pathophysiology of this disease. The HP18 cells (heterozygous c.261_266del6/c.259_261del3) showed almost null results in the activity of the IDS enzyme and presented accumulation of glycosaminoglycans (GAGs), allowing the characterization of this knockout cellular model by MPS II gene editing. An increase in the production of reactive species was demonstrated (p < .05 compared withWT vehicle group) and genistein at concentrations of 25and 50 µm decreased in vitro its production (p < .05 compared with HP18 vehicle group), but there was no effect of coenzyme Q10 in this parameter. There was a tendency for lysosomal pH change in HP18 cells in comparison to WT group and none of the antioxidants tested demonstrated any effect on this parameter. There was no increase in the activity of the antioxidant enzymes superoxide dismutase and catalase and oxidative damage to DNA in HP18 cells in comparison to WT group and neither genistein nor coenzyme q10 had any effect on these parameters. Regarding mitochondrial membrane potential, genistein induced mitochondrial depolarization in both concentrations tested (p < .05 compared with HP18 vehicle group and compared with WT vehicle group) and incubation with coenzyme Q10 demonstrated no effect on this parameter. In conclusion, it is hypothesized that our cellular model could be compared with a milder MPS II phenotype, given that the accumulation of GAGs in lysosomes is not as expressive as another cellular model for MPS II presented in the literature. Therefore, it is reasonable to expect that there is no mitochondrial depolarization and no DNA damage, since there is less lysosomal impairment, as well as less redox imbalance.

An empowered, clinically viable hematopoietic stem cell gene therapy for the treatment of multisystemic mucopolysaccharidosis type II

Mucopolysaccharidosis type II (MPS II), or Hunter syndrome, is a rare X-linked recessive lysosomal storage disorder due to a mutation in the lysosomal enzyme iduronate-2-sulfatase (IDS) gene. IDS deficiency leads to a progressive, multisystem accumulation of glycosaminoglycans (GAGs) and results in central nervous system (CNS) manifestations in the severe form. We developed up to clinical readiness a new hematopoietic stem cell (HSC) gene therapy approach for MPS II that benefits from a novel highly effective transduction protocol. We first provided proof of concept of efficacy of our approach aimed at enhanced IDS enzyme delivery to the CNS in a murine study of immediate translational value, employing a lentiviral vector (LV) encoding a codon-optimized human IDS cDNA. Then the therapeutic LV was tested for its ability to efficiently and safely transduce bona fide human HSCs in clinically relevant conditions according to a standard vs. a novel protocol that demonstrated superior ability to transduce bona fide long-term repopulating HSCs. Overall, these results provide strong proof of concept for the clinical translation of this approach for the treatment of Hunter syndrome.

A novel cartilage-targeting MOF-HMME-RGD sonosensitizer combined with sonodynamic therapy to enhance chondrogenesis and cartilage regeneration.

Articular cartilage regeneration is still a difficult task due to the cartilage's weak capacity for self-healing and the effectiveness of the available therapies. The engineering of cartilage tissue has seen widespread use of stem cell-based therapies. However, efficient orientation of line-specific bone marrow mesenchymal stem cells (BMSCs) to chondrogenesis and maintenance of chondrogenic differentiation challenged stem cell-based therapy. Herein, we developed a Fe-based metal-organic framework (MOF) loaded with hematoporphyrin monomethyl ether (HMME) and cartilage-targeting arginine-aspartate-glycine (RGD) peptide to form MOF-HMME-RGD sonosensitizer to regulate BMSCs chondrogenic differentiation for cartilage regeneration via the modulation of reactive oxygen species (ROS). By using sonodynamic therapy (SDT), the MOF-HMME-RGD demonstrated favorable biocompatibility, could generate a modest amount of ROS, and enhanced BMSCs chondrogenic differentiation through increased accumulation of glycosaminoglycan, an ECM component specific to cartilage, and upregulated expression of key chondrogenic genes (ACAN, SOX9, and Col2a1). Further, transplanted BMSCs loading MOF-HMME-RGD combined with SDT enhanced cartilage regeneration for cartilage defect repair after 8 weeks into treatment. This synergistic strategy based on MOF nanoparticles provides an instructive approach to developing alternative sonosensitizers for cartilage regeneration combined with SDT.

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.

α-L-iduronidase fused with humanized anti-human transferrin receptor antibody (lepunafusp alfa) for mucopolysaccharidosis type I: A phase 1/2 trial

Mucopolysaccharidosis type I (MPS I) causes systemic accumulation of glycosaminoglycans due to a genetic deficiency of α-L-iduronidase (IDUA), which results in progressive systemic symptoms affecting multiple organs, including the central nervous system (CNS). Because the blood-brain barrier (BBB) prevents enzymes from reaching the brain, enzyme replacement therapy is effective only against the somatic symptoms. Hematopoietic stem cell transplantation can address the CNS symptoms, but the risk of complications limits its applicability. We have developed a novel genetically modified protein consisting of IDUA fused with humanized anti-human transferrin receptor antibody (lepunafusp alfa; JR-171), which has been shown in nonclinical studies to be distributed to major organs, including the brain, bringing about systemic reductions in heparan sulfate (HS) and dermatan sulfate concentrations. Subsequently, a first-in-human study was conducted to evaluate the safety, pharmacokinetics, and exploratory efficacy of JR-171 in 18 patients with MPS I. No notable safety issues were observed. Plasma drug concentration increased dose-dependently and reached its maximum approximately 4 hours after the end of drug administration. Decreased HS in the cerebrospinal fluid suggested successful delivery of JR-171 across the BBB, while suppressed urine and serum concentrations of the substrates indicated its somatic efficacy was comparable to that of laronidase.