Lysosomal Storage Research Articles

Photoprotective Melanin is Maintained Within Keratinocytes in Storage Lysosomes

In the skin, melanin is synthesized by melanocytes within melanosomes, and transferred to keratinocytes. After being phagocytosed by keratinocytes, melanin polarizes to supranuclear caps that protect against the genotoxic effects of ultraviolet radiation. We provide evidence that melanin-containing phagosomes undergo a canonical maturation process, with the sequential acquisition of early and late endosomal markers. Subsequently, these phagosomes fuse with active lysosomes, leading to the formation of a melanin-containing phagolysosome that we named melanokerasome. Melanokerasomes achieve juxtanuclear positioning via lysosomal trafficking regulators Rab7 and RILP. Mature melanokerasomes exhibit lysosomal markers, elude connections with the endo/phagocytic pathway, are weakly degradative, retain undigested cargo and are likely tethered to the nuclear membrane. We propose that they represent a lysosomal-derived storage compartment that has exited the lysosome cycle, akin to the formation of lipofuscin in aged cells and dysfunctional lysosomes in lysosomal storage and age-related diseases. This storage lysosome allows melanin to persist for long periods, where it can exert its photoprotective effect efficiently.

The Missense Variant in the Signal Peptide of α-GLA Gene, c.13 A/G, Promotes Endoplasmic Reticular Stress and the Related Pathway's Activation.

Anderson-Fabry disease (AFD) is an X-linked multisystemic disorder with a heterogeneous phenotype, resulting from deficiency of the lysosomal enzyme α-galactosidase A (α-Gal A) and leading to globotriaosylceramide systemic accumulation. Lysosomal storage is not the unique player in organ failure and different mechanisms could drive tissue damage, including endoplasmic reticulum (ER) stress and its related signaling pathway's activation. We identified a new missense variant in the signal peptide of α-GLA gene, c.13 A/G, in a 55-year-old woman affected by chronic kidney disease, acroparesthesia, hypohidrosis, and deafness and exhibiting normal values of lysoGb3 and αGLA activity. The functional study of the new variant performed by its overexpression in HEK293T cells showed an increased protein expression of a key ER stress marker, GRP78, the pro-apoptotic BAX, the negative regulator of cell cycle p21, the pro-inflammatory cytokine, IL1β, together with pNFkB, and the pro-fibrotic marker, N-cadherin. Transmission electron microscopy showed signs of ER injury and intra-lysosomal inclusions. The proband's PBMC exhibited higher expression of TGFβ 1 and pNFkB compared to control. Our findings suggest that the new variant, although it did not affect enzymatic activity, could cause cellular damage by affecting ER homeostasis and promoting apoptosis, inflammation, and fibrosis. Further studies are needed to demonstrate the variant's contribution to cellular and tissue damage.

Intellectual Disabilities and Neurocognitive Impairment in Adult Patients with Inherited Metabolic Diseases: A UK Single Centre Experience.

Inherited metabolic diseases (IMDs) are a group of heterogeneous genetic disorders resulting in substrate accumulation, energy deficiency, or complex molecular defects due to the failure of specific molecules to act as enzymes, cofactors, transporters, or receptors in specific metabolic pathways. The pathophysiological changes seen in IMDs are sometimes associated with intellectual disability (ID) or neurocognitive decline, necessitating multidisciplinary input. We here describe our experience at one tertiary metabolic centre in the UK. We reviewed the case prevalence and existing service provision in one adult IMD service covering a multi-ethnic population of 10 million in North England. In our cohort of 2268 IMD patients, 1598 patients had general metabolic conditions (70.5%), and 670 had lysosomal storage disease/disorders (LSD)s (29.5%). The overall prevalence of ID and neurocognitive decline was found to be 15.7% (n = 357), with patients with LSDs accounting for 23.5% (n = 84) of affected patients. Given the prevalence of ID in adults with IMDs, access to multidisciplinary input from neuropsychology and neuropsychiatry services is important. Education of healthcare professionals to diagnose IMDs in patients with ID, in addition to neurocognitive and neuropsychiatric presentations, will avoid missed diagnoses of IMD and will have a positive effect on patient outcomes.

CTNS Mutations Causing Autosomal Recessive Cystinosis in a Subset of Iranian Population: Report of Two New Variants

Abstract Background: Nephropathic cystinosis (NC) is an uncommon autosomal recessive disease with abnormality in lysosomal storage that appearances in patients with mutations in the CTNS gene encoding a lysosomal transporter cystinosin. Disrupted function of this transporter is followed by accumulation of cysteine crystals in cells of many various organs. This study aimed to investigate the mutations of the CTNS gene in 20 Iranian patients suffering from NC. Materials and Methods: Twenty Iranian cystinosis patients referring to Imam Hossein Hospital of Isfahan were employed in this case-series study. After extraction of genomic DNA, the promoter and entire coding regions of CTNS were analysed using sanger sequencing in all patients. Gap–Polymerase Chain Reaction was used to detect 57 kb deletion in the CTNS gene. In silico study was performed to analyse variants. Results: The large deletion was not seen in any NC patients. Molecular analysis which conducted to screen the CTNS gene of patients, identified eight different mutations, including two new mutations, c.971_972insC and c.956_956delA, which have not been reported before, and c.681G>A mutation, which was identified as a frequently founded mutation in the Middle East and was observed in 35% of patients. In this study, five other mutations including c.1015G>A, c.922G>A, c.323_323delA, c.433C>T, and c.18_21delGACT were also observed, which have been reported in previous studies. Conclusion: The mutational spectrum in the Iranian patients is the same as previously reported mutations except that two new mutations were found. The present findings will present suggestions for regular molecular diagnosis of cystinosis in Iran.

H - 17 Neuropsychological Assessment in Rare Pediatric Neurogenetic Disorders: Considerations for Clinical Research.

Approximately 80% of rare diseases in childhood have a genetic cause. Neuropsychological assessments offer a greater understanding of the clinical presentation and trajectory of neurogenetic disorders. Given the rarity of the conditions, the limited funding allocated to study psychosocial factors, the diversity within the patient populations (e.g., country of origin, clinical phenotypes), and the limitations of our tools, there are no clear guidelines for evaluations. We aim to present a systematic approach to create assessment protocols that track disease progression and/or efficacy of therapeutic interventions. Our gene therapy program has created nine assessment protocols to evaluate conditions ranging from epileptic encephalopathies, lysosomal storage, neuromuscular, and mitochondrial diseases. Through review of past protocols, we created a neuropsychological assessment selection checklist (NASC) and standard operating procedure (SOP) checklist. The NASC systematizes updated multidisciplinary disease knowledge and relevant desirable outcomes (e.g., cognitive, motor, quality of life). Cultural elements (e.g., beliefs around health, disease, testing) and necessary accommodations (e.g., interpreters, sensory impairments) must be considered. Additional sociocultural and socioeconomic information of the sample is germane not only to contextualize results but also to help narrow possible tools. The SOP aims to increase standardization (e.g., starting points) and maximize use of the data collected (e.g., deferment reasons.). Neuropsychological assessments offer a wealth of cognitive, behavioral, emotional, and adaptive functioning data that is crucial to better understand the progression and treatment of rare neurogenetic diseases. Cultural considerations and in-depth clinical and assessment skills are essential to creating evaluation protocols that are valid, useful, and comprehensive.

Genetics of enzymatic dysfunctions in metabolic disorders and cancer.

Inherited metabolic disorders arise from mutations in genes involved in the biogenesis, assembly, or activity of metabolic enzymes, leading to enzymatic deficiency and severe metabolic impairments. Metabolic enzymes are essential for the normal functioning of cells and are involved in the production of amino acids, fatty acids and nucleotides, which are essential for cell growth, division and survival. When the activity of metabolic enzymes is disrupted due to mutations or changes in expression levels, it can result in various metabolic disorders that have also been linked to cancer development. However, there remains much to learn regarding the relationship between the dysregulation of metabolic enzymes and metabolic adaptations in cancer cells. In this review, we explore how dysregulated metabolism due to the alteration or change of metabolic enzymes in cancer cells plays a crucial role in tumor development, progression, metastasis and drug resistance. In addition, these changes in metabolism provide cancer cells with a number of advantages, including increased proliferation, resistance to apoptosis and the ability to evade the immune system. The tumor microenvironment, genetic context, and different signaling pathways further influence this interplay between cancer and metabolism. This review aims to explore how the dysregulation of metabolic enzymes in specific pathways, including the urea cycle, glycogen storage, lysosome storage, fatty acid oxidation, and mitochondrial respiration, contributes to the development of metabolic disorders and cancer. Additionally, the review seeks to shed light on why these enzymes represent crucial potential therapeutic targets and biomarkers in various cancer types.

Red-to-near-infrared self-reporting photosensitizers with high photostability for photodynamic therapy

Photodynamic therapy (PDT) is a promising tumor treatment method, in which the design of photosensitizers is particularly critical. Red-to-near-infrared (NIR) photosensitizers are beneficial to the implementation of the PDT process. However, the visualizable self-reporting PDT process cannot be fulfilled because most red-to-NIR photosensitizers have poor photostability. Here, we report a photostable red-to-NIR D-A-D photosensitizer (TPA-BPY) using BOPHY as the acceptor and triphenylamine as the donor. As far as we know, TPA-BPY is the first red-to-NIR BOPHY photosensitizer with advantages such as large molar extinction coefficient and high photostability. TPA-BPY can induce the production of singlet oxygen (1O2) under light, successfully achieving photodynamic therapy for MCF-7 cells. More importantly, TPA-BPY achieved self-reporting of the PDT-induced apoptosis process. TPA-BPY was localized in lysosomes and monitored for increased polarity during lysosomal storage and decreased polarity of apoptotic cells. This work provides an effective strategy for constructing polar sensitive near infrared self-reporting photosensitizers for PDT and its process monitoring.

Experiences of patients and their family members with metachromatic leukodystrophy, adrenoleukodystrophy, and Krabbe disease: a qualitative systematic review protocol.

The objective of this review is to synthesize the experiences of patients with metachromatic leukodystrophy (MLD), adrenoleukodystrophy (ALD), and Krabbe disease and the experiences of their family members. MLD, ALD, and Krabbe disease are rare disorders that are classified as lysosomal storage or peroxisomal disorders, with similar presentations as leukodystrophy. As these diseases cause cognitive and neurological decline due to the progression of leukodystrophy associated with demyelination, they have significant impact on the lives of patients and their families. It is important to identify the impact and challenges of these diseases on patients' lives and on their families, as well as to synthesize qualitative studies regarding their experiences. We will consider studies including patients with MLD, ALD, or Krabbe disease and their family members. These experiences will include the challenges, dissatisfactions, and frustrations with symptoms and treatments; complications of hematopoietic stem cell transplantation; and the increased caregiver burden with disease progression. This is important since the impacts of disease progression are experienced in a variety of settings beyond the hospital, such as in the community and at home. The search strategy will follow JBI methodology and be conducted in 3 steps: an initial limited search, a comprehensive database search, and a reference search of the included articles. MEDLINE, CINAHL Plus, PsycINFO, and Scopus will be searched with no restriction on language or publication dates. The study selection, critical appraisal, data extraction, and data synthesis will be performed according to JBI guidelines for systematic reviews of qualitative research. Final syntheses will be assessed using the ConQual approach. PROSPERO CRD42022318805.

Sugar-Derived Amidines and Congeners: Structures, Glycosidase Inhibition and Applications.

Glycosidases, the enzymes responsible for the breakdown of glycoconjugates, including di-, oligo- and polysaccharides, are present across all kingdoms of life. The extreme chemical stability of the glycosidic bond combined with the catalytic rates achieved by glycosidases makes them among the most proficient of all enzymes. Given their multitude of roles in vivo, inhibition of these enzymes is highly attractive with potential in the treatment of a vast array of pathologies ranging from lysosomal storage and diabetes to viral infections. Therefore great efforts have been invested in the last three decades to design and synthesize inhibitors of glycosidases leading to a number of drugs currently on the market. Amongst the vast array of structures that have been disclosed, sugars incorporating an amidine moiety have been the focus of many research groups around the world because of their glycosidase transition state-like structure. In this review, we report and discuss the structure, the inhibition profile, and the use of these molecules, including related structural congeners as transition state analogs.

Identification of novel mutations among Iranian NPC1 patients: a bioinformatics approach to predict pathogenic mutations

BackgroundNiemann-Pick disease type C (NPC) is a rare lysosomal neurovisceral storage disease caused by mutations in the NPC 1 (95%) or NPC2 (5%) genes. The products of NPC1 and NPC2 genes play considerable roles in glycolipid and cholesterol trafficking, which could consequently lead to NPC disease with variable phenotypes displaying a broad spectrum of symptoms.MaterialsIn the present study 35 Iranian NPC unrelated patients were enrolled. These patients were first analysed by the Filipin Staining test of cholesterol deposits in cells for NPC diagnostics. Genomic DNA was extracted from the samples of peripheral blood leukocytes in EDTA following the manufacturer's protocol. All exon–intron boundaries and coding exons of the NPC1gene were amplified by polymerase chain reaction (PCR) using appropriate sets of primers. Thereafter, the products of PCR were sequenced and analysed using the NCBI database (https://blast.ncbi.nlm.nih.gov/Blast.cgi). The variants were reviewed by some databases including the Human Gene Mutation Database (HGMD) (http://www.hgmd.cf.ac.uk/ac/index.php) and ClinVar (https://www.ncbi.nlm.nih.gov/clinvar (. Moreover, all the variants were manually classified in terms of the American College of Medical Genetics and Genomics (ACMG) guideline.ResultsThe sequence analysis revealed 20 different variations, 10 of which are new, including one nonsense mutation (c.406C > T); three small deletions, (c.3126delC, c.2920_2923delCCTG, and c.2037delG); and six likely pathogenic missense mutations, (c.542C > A, c.1970G > A, c.1993C > G, c.2821 T > C, c.2872C > G, and c.3632 T > A). Finally, the pathogenicity of these new variants was determined using the ACMG guidelines.ConclusionThe present study aimed to facilitate the prenatal diagnosis of NPC patients in the future. In this regard, we identified 10 novel mutations, and verified that the majority of them occurred in six NPC1 exons (5, 8, 9, 13, 19, and 21), that should be considered with a high priority for Iranian patients' cost-effective evaluation.

Sialidase neu4 deficiency is associated with neuroinflammation in mice.

Sialidases catalyze the removal of sialic acid residues from glycoproteins, oligosaccharides, and sialylated glycolipids. Sialidase Neu4 is in the lysosome and has broad substrate specificity. Previously generated Neu4-/- mice were viable, fertile and lacked gross morphological abnormalities, but displayed a marked vacuolization and lysosomal storage in lung and spleen cells. In addition, we showed that there is an increased level of GD1a ganglioside and a markedly decreased level of GM1 ganglioside in the brain of Neu4-/- mice. In this study, we further explored whether sialidase Neu4 deficiency causes neuroinflammation. We demostrated that elevated level of GD1a and GT1b is associated with an increased level of LAMP1-positive lysosomal vesicles and Tunel-positive neurons correlated with alterations in the expression of cytokines and chemokines in adult Neu4-/- mice. Astrogliosis and microgliosis were also significantly enhanced in the hippocampus, and cerebellum. These changes in brain immunity were accompanied by motor impairment in these mice. Our results indicate that sialidase Neu4 is a novel mediator of an inflammatory response in the mouse brain due to the altered catabolism of gangliosides.

Current and Future Prospects for Gene Therapy for Rare Genetic Diseases Affecting the Brain and Spinal Cord.

In recent years, gene therapy has been raising hopes toward viable treatment strategies for rare genetic diseases for which there has been almost exclusively supportive treatment. We here review this progress at the pre-clinical and clinical trial levels as well as market approvals within diseases that specifically affect the brain and spinal cord, including degenerative, developmental, lysosomal storage, and metabolic disorders. The field reached an unprecedented milestone when Zolgensma® (onasemnogene abeparvovec) was approved by the FDA and EMA for in vivo adeno-associated virus-mediated gene replacement therapy for spinal muscular atrophy. Shortly after EMA approved Libmeldy®, an ex vivo gene therapy with lentivirus vector-transduced autologous CD34-positive stem cells, for treatment of metachromatic leukodystrophy. These successes could be the first of many more new gene therapies in development that mostly target loss-of-function mutation diseases with gene replacement (e.g., Batten disease, mucopolysaccharidoses, gangliosidoses) or, less frequently, gain-of-toxic-function mutation diseases by gene therapeutic silencing of pathologic genes (e.g., amyotrophic lateral sclerosis, Huntington's disease). In addition, the use of genome editing as a gene therapy is being explored for some diseases, but this has so far only reached clinical testing in the treatment of mucopolysaccharidoses. Based on the large number of planned, ongoing, and completed clinical trials for rare genetic central nervous system diseases, it can be expected that several novel gene therapies will be approved and become available within the near future. Essential for this to happen is the in depth characterization of short- and long-term effects, safety aspects, and pharmacodynamics of the applied gene therapy platforms.

Abstract 1019: The MET inhibitor tepotinib shows sustained effects on MET phosphorylation and viability in cellular washout experiments

Abstract It is well accepted that a drug's efficacy is modulated by the affinity of the drug to the target of interest and the stability of the protein/inhibitor complex. Additionally, drug efficacy is affected by pharmacokinetic properties. For example, lipophilic weak bases are able to easily permeate membranes at neutral pH in a non-protonated form, but also tend to accumulate in acidic compartments such as lysosomes. Consequently, lysosomes can act as a drug reservoir. The degree of lysosomal sequestration generally correlates with the pKa value of the basic function, and although the process is considered to be fully reversible, the degree and accessibility of the lysosomal reservoir heavily depends on compound-specific physicochemical properties. MET inhibitors such as crizotinib, capmatinib, savolitinib and tepotinib are providing the opportunity to study how differences in the physicochemical profiles of MET inhibitors affect the interplay of drug-target residence time and lysosomal storage, and how these factors translate into target inhibition and cell viability effects under washout conditions. Human lung cancer cell lines were treated with MET inhibitors across a range of concentrations for 1 h, cells were washed to remove compounds in the supernatant, and remaining compound activity was analyzed by measuring MET phosphorylation and lung cancer cell viability. Tepotinib showed persistent effects in both assays with significant differences observed between the tested MET inhibitors. In the viability assay comparing standard and washout conditions, the half-maximal inhibitory concentrations of tepotinib and crizotinib increased by a factor ranging from 10 to 20. In contrast, those of capmatinib and savolitinib increased by a factor >250, indicating a more sustained efficacy for tepotinib and crizotinib under washout conditions. Here, we present data on the underlying mechanisms affecting cellular efficacy under washout conditions, including residence time via surface plasmon resonance analysis, compound-partition coefficients via liquid chromatography with tandem mass spectrometry quantification, and lysosomal storage via a competitive dye displacement assay. This comparative analysis provides strong evidence that tepotinib demonstrates persistent efficacy in dynamic cellular systems, exceeding that of several other MET inhibitors. The underlying reason for this observation is probably the consequence of a long residence time of tepotinib (~20 h) combined with an optimal physicochemical profile allowing for a beneficial contribution of lysosomal retention. These in vitro findings may also explain the sustained pharmacokinetic and pharmacodynamic in vivo characteristics of tepotinib. Citation Format: Nina Berges, Jan Henrik Klug, Anna Eicher, Jennifer Loehr, Daniel Schwarz, Joerg Bomke, Birgitta Leuthner, Dominique Perrin, Oliver Schadt. The MET inhibitor tepotinib shows sustained effects on MET phosphorylation and viability in cellular washout experiments [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1019.

A Niemann\u2010pick C1 disease child with BCG-itis: a case report and analysis

BackgroundNiemann-Pick C disease is a rare autosomal recessive lysosomal lipid storage disorder. Some primary immunodeficiency diseases patients developed regional disease or disseminated disease after vaccinating BCG. It is unclear whether NPC gene deficiency is associated with Mycobacteria infection.Case presentationWe report and discuss a case of a child who presented at the age of 6 months with NPC1 and BCG-itis. The patient was treated with Miglustat and the symptom of lymphadenopathy was improved.ConclusionsWe reasonably speculate that NPC1 is a susceptibility gene of Mtb infection and mainly affects innate immunity. Once diagnosed, the infant should not be vaccinated with BCG and early treated.

Advances in diagnosis and management of Pompe disease.

Pompe disease is an autosomal recessive lysosomal glycogen storage disorder caused by the deficiency of acid alpha-glucosidase and subsequent progressive glycogen accumulation due to mutations in the GAA gene. Pompe disease manifests with a broad spectrum of disease severity, ranging from severe infantile-onset diseases such as hypotonia and hypertrophic cardiomyopathy to late-onset diseases such as myopathy and respiratory compromise. The diagnosis requires demonstration of deficiency of the lysosomal acid alpha-glucosidase enzyme, which can be assayed in dried blood spot or liquid blood samples, together with supportive biomarker tests, and confirmed with molecular genetic analysis. Targeted screening of at-risk populations and universal newborn screening can result in earlier diagnosis and enable earlier treatment initiation, which result in the potential improvement of clinical outcomes. Disease-modifying treatment with enzyme replacement therapy has partially altered the natural history of the disease, but more efficacious novel therapies are under evaluation including second-generation enzyme replacement therapies, molecular chaperones and gene therapy approaches. Long-term survivors with Pompe disease are now manifesting novel aspects of the disease including widespread vascular disease, smooth muscle and central nervous system involvement, and these emerging phenotypes will require additional specific therapeutic approaches.

Stratification of Fabry mutations in clinical practice: a closer look at α-galactosidase A-3D structure.

Fabry disease (FD) is an X-linked lysosomal storage and multi-system disorder due to mutations in the α-galactosidase A (α-GalA) gene. We investigated the impact of individual amino acid exchanges in the α-GalA 3D-structure on the clinical phenotype of FD patients. We enrolled 80 adult FD patients with α-GalA missense mutations and stratified them into three groups based on the amino acid exchange location in the α-GalA 3D-structure: patients with active site mutations, buried mutations and other mutations. Patient subgroups were deep phenotyped for clinical and laboratory parameters and FD-specific treatment. Patients with active site or buried mutations showed a severe phenotype with multi-organ involvement and early disease manifestation. Patients with other mutations had a milder phenotype with less organ impairment and later disease onset. α-GalA activity was lower in patients with active site or buried mutations than in those with other mutations (P<0.01 in men; P<0.05 in women) whilst lyso-Gb3 levels were higher (P<0.01 in men; <0.05 in women). The type of amino acid exchange location in the α-GalA 3D-structure determines disease severity and temporal course of symptom onset. Patient stratification using this parameter may become a useful tool in the management of FD patients.

P0088THE INFILTRATION OF T AND B LYMPHOCYTES AND NK CELLS IN KIDNEY BIOPSIES OF PATIENTS WITH FABRY DISESE UNDER ENZYME REPLACEMENT THERAPHY

Abstract Background and Aims Fabry Disease (FD) is a lysosomal glycosphingolipid storage disorder. Kidneys are affected in FD. Despite enzyme replacement theraphy (ERT), some patient still have an ongoing deterioration of renal functions probably secondary to inappropriate immune responses. There is no data regarding NK cell subtypes and the exact relation with B-T lymphocytes and NK cells in patients with FD. We aimed to analyze subtypes of NK cells in patients with FD and compared these results with healthy subjects. Additionally, we analyzed the renal biopsy (RBx) materials of our patients prior to ERT in terms of B, T and NK cell infiltration and compared these cells in some of our FD patients after 4 years of ERT. Method 15 patients with FD and 10 healthy controls were included in the study. Of 15 patients, 8 patients were receiving agalsidase alfa or beta. Blood samples obtained from both group were taken into 2 ml EDTA tube to evaluate peripheral NK cell subgroups according to CD56 and CD16 expression and CD3, CD4, CD8 expression to determine subtypes T cells. These cells were evaluated by flow cytometry technique. The RBx of 10 patients with FD were evaluated before ERT and 3 were reevaluated after 4 years of ERT in terms of T-B, NK and plasma cells infiltration of kidney. The paraffin blocks of specimens were examined with HE, PAS, Masson-trichrome and toluidine blue staining and frozen blocks were examined with red-oil 10 staining Results The characteristics of patients with FD and healthy controls are depicted in Figure 1. Except proteinuria, there were no significant differences in terms of biochemical parameters between two groups. According to flow-cytometric analyses, total percentage of NK and T helper 1, 2, 17 and Treg cells of FD patients are similar to controls (Fig 1). When we analyzed subgroups of NK cells and determined that CD56dimCD16dimNK cells were increased, however, CD56dimCD16brightNK cells were decreased in patients with FD compared to controls (Fig1). We performed RBx of 10 patients. The percentages of CD3, 4, 8 positive Tcells, CD19, CD20 positive B cells, CD 16, 56 positive NK cells and CD 138 positive plasma cell infiltration are shown in Fig 2. According to RBx findings prior to ERT, all patients had interstistial fibrosis (IF), podocyte vacuoles (PV), podocyte inclusion (PI), CD3, CD4, CD16, CD56 positivity at different levels. In contrast, almost none of the patients had CD19, CD20, CD138 positivity. We rebiopsied 3 patients after 4 years of ERT and reevaluated specimens in terms of IF, global and segmental sclerosis (SS), PV, PI and the percentages of CD3, CD4, CD16, CD56, CD 19, CD 20, CD 138 positivity. 2 rebiopsied patients from the same family had increased serum creatinine and proteinuria despite 4 years of regular ERT. In the second biopsy of these two patients, we found that global sclerosis (GS), IF and PI are increased and abundant CD19, CD20 and CD 138 positive cells were seen which were almost absent in the first biopsy. The other patient from another family, had mildly increased proteinuria and had no creatinine increment after 4 years of ERT. In this patient, we found that GS, SS, IF, PI and arterial sclerosis were increased, however CD 3, 4, 8 positive T cells were decreased and no changes in the percentage of CD16, 56 positive NK cells. We could not demonstrate CD 19, 20, 138 positivity in the latter patient. Conclusion Our group, for the first time, demonstrated that CD56dimCD16dimsubtype of NK cells is increased in FD which is closely associated with cellular cytotoxity in normal population. Additionaly, CD 19 and CD 20 positive B cell infiltration are increased and glomerular and interstitial changes are advanced in some patients with ongoing kidney function deterioration despite 4 years of regular ERT. Hence, infiltration of Bcells in the kidneys of patients under ERT might change our therapeutic approaches in the near future. Further studies are needed to clarify the exact roles of B T and NK cells in FD.

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

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.

Evaluation of different suspicion indices in identifying patients with Niemann-Pick disease Type C in clinical practice: a post hoc analysis of a retrospective chart review

BackgroundNiemann-Pick disease Type C (NP-C) is a lysosomal lipid storage disorder with varying symptomatology depending on the age of onset. The diagnosis of NP-C is challenging due to heterogeneous nonspecific clinical presentation of the disease. NP-C Suspicion Index (SI) was developed to aid screening and identification of patients with suspicion of NP-C for further clinical evaluation. Here we assess the performance of five NP-C SI models to identify patients with NP-C compared with clinical practice to determine the best SI model for identification of each clinical form of NP-C by age.MethodsThis was a post hoc analysis of a retrospective chart review of patient data collected from five expert NP-C centers. The study assessed the proportion of patients with NP-C who could have been identified using the Original SI, Refined SI, 2/7 SI, 2/3 SI, and Early-Onset SI and evaluated the performance of each SI against clinical practice. A score above a threshold of 70 points for the Original SI, 40 points for the Refined SI, 6 points for the Early-Onset SI, and 2 points for the 2/7 and 2/3 SIs represented identification of NP-C.ResultsThe study included 63 patients, and of these, 23.8% had a family history of NP-C. Of the available SI tools, the Refined SI performed well in identifying patients with NP-C across all age groups (77.8% infantile, 100% juvenile and 100% adult groups), and earlier identification than clinical diagnosis would have been possible in 50.0% of infantile, 72.7% of juvenile and 87.0% of adult patients. Patients who were not detected by the Refined SI prior to clinical diagnosis mainly presented with delayed developmental milestones, visceral manifestations, neurologic hypotonia, clumsiness, ataxia, vertical supranuclear gaze palsy, parent or siblings with NP-C, dysarthria/dysphagia and psychotic symptoms.ConclusionThis study demonstrated the applicability of various SI models for screening and identification of patients with NP-C for further clinical evaluation. Although NP-C is rare and the patient population is limited, this study was conducted in a real-world setting and confirms SI models as useful screening tools that facilitate identification of patients with NP-C earlier in their disease course.

ClC-7 Regulates the Pattern and Early Development of Craniofacial Bone and Tooth.

Human CLCN7 encodes voltage-gated chloride channel 7 (ClC-7); mutations of CLCN7 lead to osteopetrosis which is characterized by increased bone mass and impaired osteoclast function. In our previous clinical practice, we noticed that osteopetrosis patients with CLCN7 mutations had some special deformities in craniofacial morphology and tooth dysplasia. It is unclear whether these phenotypes are the typical features of CLCN7 involved osteopetrosis and whether ClC-7 could regulate the development of craniofacial bone and tooth in some signaling pathways.Methods: First, we collected 80 osteopetrosis cases from the literature and compared their craniofacial and dental phenotypes. Second, four osteopetrosis pedigrees with CLCN7 mutations were recruited from our clinic for gene testing and clinical analysis of their craniofacial and dental phenotypes. Third, we used a zebrafish model with clcn7 morpholino treatment to detect the effects of ClC-7 deficiency on the development of craniofacial and dental phenotypes. General observation, whole mount alcian blue and alizarin red staining, whole mount in situ hybridization, scanning electron microscope observation, lysoSensor staining, Q-PCR and western blotting were performed to observe the in vivo characteristics of craniofacial bone and tooth changes. Fourth, mouse marrow stromal cells were further primarily cultured to detect ClC-7 related mRNA and protein changes using siRNA, Q-PCR and western blotting.Results: Over 84% of osteopetrosis patients in the literature had some typical craniofacial and tooth phenotypes, including macrocephaly, frontal bossing, and changes in shape and proportions of facial skeleton, and these unique features are more severe and frequent in autosomal recessive osteopetrosis than in autosomal dominant osteopetrosis patients. Our four pedigrees with CLCN7 mutations confirmed the aforementioned clinical features. clcn7 knockdown in zebrafish reproduced the craniofacial cartilage defects and various dental malformations combined the decreased levels of col10a1, sp7, dlx2b, eve1, and cx43. Loss of clcn7 function resulted in lysosomal storage in the brain and jaw as well as downregulated cathepsin K (CTSK). The craniofacial phenotype severity also presented a dose-dependent relationship with the levels of ClC-7 and CTSK. ClC-7/CTSK further altered the balance of TGF-β/BMP signaling pathway, causing elevated TGF-β-like Smad2 signals and reduced BMP-like Smad1/5/8 signals in clcn7 morphants. SB431542 inhibitor of TGF-β pathway partially rescued the aforementioned craniofacial bone and tooth defects of clcn7 morphants. The ClC-7 involved CTSK/BMP and SMAD changes were also confirmed in mouse bone marrow stromal cells.Conclusion: These findings highlighted the vital role of clcn7 in zebrafish craniofacial bone and tooth development and mineralization, revealing novel insights for the causation of osteopetrosis with CLCN7 mutations. The mechanism chain of ClC-7/CTSK/ TGF-β/BMP/SMAD might explain the typical craniofacial bone and tooth changes in osteopetrosis as well as pycnodysostosis patients.