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Salmonella Typhimurium is a causative agent of nontyphoidal salmonellosis, for which there is a lack of a clinically approved vaccine in humans. As an intracellular pathogen, Salmonella impacts many cellular pathways. However, the intercellular communication mechanism facilitated by host-derived small extracellular vesicles (EVs), such as exosomes, is an overlooked aspect of the host responses to this infection. We used a comprehensive proteome-based network analysis of exosomes derived from Salmonella -infected macrophages to identify host molecules that are trafficked via these EVs. This analysis predicted that the host-derived small EVs generated during macrophage infection stimulate macrophages and promote activation of T helper 1 (Th1) cells. We identified that exosomes generated during infection contain Salmonella proteins, including unique antigens previously shown to stimulate protective immune responses against Salmonella in murine studies. Furthermore, we showed that host EVs formed upon infection stimulate a mucosal immune response against Salmonella infection when delivered intranasally to BALB/c mice, a route of antigen administration known to initiate mucosal immunity. Specifically, the administration of these vesicles to animals stimulated the production of anti- Salmonella IgG antibodies, such as anti-OmpA antibodies. Exosomes also stimulated antigen-specific cell-mediated immunity. In particular, splenic mononuclear cells isolated from mice administered with exosomes derived from Salmonella -infected antigen-presenting cells increased CD4+ T cells secreting Th1-type cytokines in response to Salmonella antigens. These results demonstrate that small EVs, formed during infection, contribute to Th1 cell bias in the anti- Salmonella responses. Collectively, this study helps to unravel the role of host-derived small EVs as vehicles transmitting antigens to induce Th1-type immunity against Gram-negative bacteria. Understanding the EV-mediated defense mechanisms will allow the development of future approaches to combat bacterial infections.

SEE PDF] The clinical history and bone marrow biopsy findings were suspicious for lysosomal storage disease, and subsequent sphingomyelinase enzymatic activity (dried-blot spot, DBS) showed decreased residual activity (0.4 nmol/L, N ≥ 2.5 nmol/L) consistent with the late-onset non-neuronopathic form of ASMD, which is characterized by the development of hepatosplenomegaly and associated thrombocytopenia. ETHICS STATEMENT This study protocol was reviewed and approved by the Weill Cornell Medicine Institutional Review Board (WCM-IRB) at Weill Cornell Medical College of Cornell University, approval number 0107004999. The New York Presbyterian Hospital/Weill Cornell Medicine is in compliance with the CARE guidelines for case reports.

Gaucher disease (GD) is a lysosomal storage disease caused by the deficiency of glucocerebrosidase characterized by a broad spectrum of clinical manifestations including hepatosplenomegaly, bone infiltration, and cytopenia, and even central nervous system involvement. Bone manifestations are typical of the GD-I and partially responded to mainstay therapy. Ambroxol (ABX), an approved cough-suppressant, was identified as an enzyme-enhancement agent of the residual activity of glucocerebrosidase mutants derived from different misfolding-mutations in the GBA gene. Here, we describe the early beneficial effects of ABX on skeletal and hematological manifestations of a child suffering with progressive GD-I.

Ubiquitination is an important protein modification that regulates various essential cellular processes, including the functions of innate immune cells. Deubiquitinases are enzymes responsible for removing ubiquitin modification from substrates, and the regulation of deubiquitinases in macrophages during infection with Typhimurium and remains unknown. To identify deubiquitinases regulated in human macrophages during bacterial infection, an activity-based proteomics screen was conducted. The effects of pharmacological inhibition of the identified deubiquitinase, USP8, were examined, including its impact on bacterial survival within macrophages and its role in autophagy regulation during infection. Several deubiquiitnases were differentially regulated in infected macrophages. One of the deubiquitinases identified was USP8, which was downregulated upon infection. Inhibition of USP8 was associated with a decrease in bacterial survival within macrophages, and it was found to play a distinct role in regulating autophagy during infection. The inhibition of USP8 led to the downregulation of the p62 autophagy adaptor. The findings of this study suggest a novel role of USP8 in regulating autophagy flux, which restricts intracellular bacteria, particularly during infection.

Importance Ambroxol was identified as an enhancer of stability and residual activity of several misfolded glucocerebrosidase variants in 2009. Objectives To assess hematologic and visceral outcomes, biomarker changes, and safety of ambroxol therapy for patients with Gaucher disease (GD) without disease-specific treatment. Design, Setting, and Participants Patients with GD who could not afford enzyme replacement therapy were enrolled and received oral ambroxol from May 6, 2015, to November 9, 2022, at Xinhua Hospital, affiliated with Shanghai Jiao Tong University School of Medicine, Shanghai, China. Thirty-two patients with GD (29 with GD type 1, 2 with GD type 3, and 1 with GD intermediate types 2-3) were enrolled. Of those, 28 patients were followed up for longer than 6 months; 4 were excluded due to loss of follow-up. Data analyses were performed from May 2015 to November 2022. Intervention An escalating dose of oral ambroxol (mean [SD] dose, 12.7 [3.9] mg/kg/d). Main Outcomes and Measures Patients with GD receiving ambroxol were followed up in a genetic metabolism center. Biomarkers of chitotriosidase activity and glucosylsphingosine level, liver and spleen volumes, and hematologic parameters were measured at baseline and various time points throughout the ambroxol treatment. Results A total of 28 patients (mean [SD] age, 16.9 [15.3] years; 15 male patients [53.6%]) received ambroxol for a mean (SD) duration of 2.6 (1.7) years. Two patients with severe symptoms at baseline experienced deterioration of hematologic parameters and biomarkers and were deemed nonresponders; clinical response was observed in the other 26 patients. After 2.6 years of ambroxol treatment, the mean (SD) hemoglobin concentration improved from 10.4 (1.7) to 11.9 (1.7) g/dL (mean [SD], 1.6 [1.7] g/dL; 95% CI, 0.8-2.3 g/dL;P < .001), and the mean (SD) platelet count improved from 69 (25) to 78 (30) × 103/µL (mean [SD], 9 [22] × 103/µL; 95% CI, −2 to 19 × 103/µL;P = .09). The mean (SD) spleen volume decreased from 17.47 (7.18) to 12.31 (4.71) multiples of normal (MN) (mean [SD], −5.16 [5.44] MN; 95% CI, −10.19 to −0.13;P = .04), and the mean (SD) liver volume decreased from 1.90 (0.44) to 1.50 (0.53) MN (mean [SD], −0.39 [0.42] MN; 95% CI, −0.75 to −0.04;P = .03). Biomarker median percentage changes from baseline were −43.1% for chitotriosidase activity (from 14 598 [range, 3849-29 628] to 8312 [range, 1831-16 842] nmol/mL/h;z = −3.413;P = .001) and −34.1% for glucosylsphingosine level (from 251.3 [range, 73.6-944.2] to 165.7 [range, 21.3-764.8] ng/mL;z = −2.756;P = .006). Patients were divided into subgroups according to age when initiating treatment; those who received treatment at a younger age (mean [SD] age, 6.3 [2.7] years) experienced more rapid improvements: hemoglobin concentration increased by 16.5% (from 10.3 [1.5] to 12.0 [1.5] g/dL; mean [SD] change, 1.6 [1.6] g/dL; 95% CI, 0.7-2.5 g/dL;P = .002), and platelet count increased by 12.0% (from 75 [24] to 84 [33] × 103/µL; mean [SD] change, 9 [26] × 103/µL; 95% CI, −5 to 24 × 103/µL;P = .17); whereas chitotriosidase activity decreased by 64.0% (from 15 710 [range, 4092-28 422] to 5658 [range, 1146-16 843] nmol/mL/h;z = −2.803;P = .005), and glucosylsphingosine level decreased by 47.3% (from 248.5 [range, 122.8-674.9] to 131.0 [range, 41.1-448.5] ng/mL;z = −2.385;P = .02). Three of the 28 patients experienced mild and transient adverse events. Conclusions and Relevance In this case series of ambroxol repurposing among patients with GD, long-term treatment with ambroxol was safe and associated with patient improvement. Improvements in hematologic parameters, visceral volumes, and plasma biomarkers were larger among patients with relatively mild symptoms of GD and patients who received initial treatment at younger ages.

Small molecules have been identified as potential therapeutic agents for lysosomal storage diseases (LSDs), inherited metabolic disorders caused by defects in proteins that result in lysosome dysfunctional. Some small molecules function assisting the folding of mutant misfolded lysosomal enzymes that are otherwise degraded in ER-associated degradation. The ultimate result is the enhancement of the residual enzymatic activity of the deficient enzyme. Most of the high throughput screening (HTS) assays developed to identify these molecules are single-target biochemical assays. Here we describe a cell-based assay using patient cell lines to identify small molecules that enhance the residual arylsulfatase A (ASA) activity found in patients with metachromatic leukodystrophy (MLD), a progressive neurodegenerative LSD. In order to generate sufficient cell lines for a large scale HTS, primary cultured fibroblasts from MLD patients were transformed using SV40 large T antigen. These SV40 transformed (SV40t) cells showed to conserve biochemical characteristics of the primary cells. Using a specific colorimetric substrate para-nitrocatechol sulfate (pNCS), detectable ASA residual activity were observed in primary and SV40t fibroblasts from a MLD patient (ASA-I179S) cultured in multi-well plates. A robust fluorescence ASA assay was developed in high-density 1,536-well plates using the traditional colorimetric pNCS substrate, whose product (pNC) acts as \"plate fluorescence quencher\" in white solid-bottom plates. The quantitative cell-based HTS assay for ASA generated strong statistical parameters when tested against a diverse small molecule collection. This cell-based assay approach can be used for several other LSDs and genetic disorders, especially those that rely on colorimetric substrates which traditionally present low sensitivity for assay-miniaturization. In addition, the quantitative cell-based HTS assay here developed using patient cells creates an opportunity to identify therapeutic small molecules in a disease-cellular environment where potentially disrupted pathways are exposed and available as targets.

Metachromatic leukodystrophy (MLD) is an autosomal recessive lysosomal disorder caused by the deficiency of arylsulfatase A (ASA), resulting in impaired degradation of sulfatide, an essential sphingolipid of myelin. The clinical manifestations of MLD are characterized by progressive demyelination and subsequent neurological symptoms resulting in severe debilitation. The availability of therapeutic options for treating MLD is limited but expanding with a number of early stage clinical trials already in progress. In the development of therapeutic approaches for MLD, scientists have been facing a number of challenges including blood-brain barrier (BBB) penetration, safety issues concerning therapies targeting the central nervous system, uncertainty regarding the ideal timing for intervention in the disease course, and the lack of more in-depth understanding of the molecular pathogenesis of MLD. Here, we discuss the current status of the different approaches to developing therapies for MLD. Hematopoietic stem cell transplantation has been used to treat MLD patients, utilizing both umbilical cord blood and bone marrow sources. Intrathecal enzyme replacement therapy and gene therapies, administered locally into the brain or by generating genetically modified hematopoietic stem cells, are emerging as novel strategies. In pre-clinical studies, different cell delivery systems including microencapsulated cells or selectively neural cells have shown encouraging results. Small molecules that are more likely to cross the BBB can be used as enzyme enhancers of diverse ASA mutants, either as pharmacological chaperones, or proteostasis regulators. Specific small molecules may also be used to reduce the biosynthesis of sulfatides, or target different affected downstream pathways secondary to the primary ASA deficiency. Given the progressive neurodegenerative aspects of MLD, also seen in other lysosomal diseases, current and future therapeutic strategies will be complementary, whether used in combination or separately at specific stages of the disease course, to produce better outcomes for patients afflicted with this devastating inherited disorder.

Background: Niemann-Pick disease type C1 (NP-C1) is a rare, autosomal-recessive neurodegenerative disorder with no United States Food and Drug Administration (FDA)-approved drug. Lithium has been shown to have considerable neuroprotective effects for neurological disorders such as bipolar disorder, Alzheimer’s disease and stroke and has been tested in many clinical trials. However, the pharmacological effect of lithium on NP-C1 neurodegenerative processes has not been investigated. The aim of this study was to provide an initial evaluation of the safety and feasibility of lithium carbonate in patients with NP-C1. Methods: A total of 13 patients diagnosed with NP-C1 who met the inclusion criteria received lithium orally at doses of 300, 600, 900, or 1,200 mg daily. The dose was reduced based on tolerance or safety observations. Plasma 7-ketocholesterol (7-KC), an emerging biomarker of NP-C1, was the primary endpoint. Secondary endpoints included NPC Neurological Severity Scores (NNSS) and safety. Results: Of the 13 patients with NP-C1 (12–33 years) enrolled, three withdrew (discontinuation of follow-up outpatient visits). The last observed post-treatment values of 7-KC concentrations (128 ng/ml, SEM 20) were significantly lower than pretreatment baselines values (185 ng/ml, SEM 29; p = 0.001). The mean NNSS was improved after lithium treatment at 12 months ( p = 0.005). Improvement in swallowing capacity was observed in treated patients ( p = 0.014). No serious adverse events were recorded in the patients receiving lithium. Conclusion: Lithium is a potential therapeutic option for NP-C1 patients. Larger randomized and double-blind clinical trials are needed to further support this finding. Clinical Trial Registration: ClinicalTrials.gov , NCT03201627.

POLR3‐related hypomyelinating leukodystrophy (POLR3‐HLD) is a rare inherited neurological disorder caused by biallelic pathogenic variants in specific genes encoding subunits of RNA polymerase III (Pol III). Here, we report the third patient worldwide with pathogenic variants in POLR3K and clinical features consistent with POLR3‐HLD. The female patient presented with mild intellectual and behavioural disturbances in childhood, as well as growth delay, with brain MRI revealing diffuse hypomyelination and a pattern consistent with POLR3‐HLD. In adolescence, she manifested minor motor dysfunction. Next‐generation sequencing revealed a paternally inherited missense variant in POLR3K (c.322G>T; p.D108Y) and a maternally inherited large deletion, spanning approximately 17.8 kb from chr16:30,362‐48,162. The missense variant is located at the C‐terminus position of the protein and is predicted to impair residue interactions and cause steric interference in enzyme conformational changes. The large deletion encompasses the third and last exon of POLR3K , leading to a likely amorphic truncated protein product lacking the final 42 amino acids from the total 108 amino acid–length protein. Studies of RNA‐level expression showed a significant reduction in the levels of POLR3K RNA in the patient compared to the control. In considering whether the transcriptional function of Pol III was affected, the expression of several Pol III‐transcribed RNAs was measured, where the levels of several distinct tRNAs were significantly reduced in the patient while the expression of other RNA transcripts was not decreased, suggesting that Pol III retains partial function. This study provides further evidence for the association of pathogenic variants in POLR3K with POLR3‐HLD, expanding the spectrum of pathogenic variants in genes encoding for Pol III subunits associated with this disease.

The lysosomal storage disorders (LSDs) are a group of inborn organelle disorders, clinically heterogeneous, and biochemically characterized by accumulation of nondegraded macromolecules primarily in the lysosomal and other cellular compartments. Given the common and essential cellular function of the lysosomal system in different organs and systems, patients afflicted with these disorders present a broad range of clinical problems, including neurological problems, visceromegaly, and skeletal deformities. Onset of symptoms may range from fetal period to adulthood. The neurological problems include developmental delay, seizures, acroparesthesia, motor weakness, muscle wasting, behavioral/psychiatric disturbances, cerebrovascular ischemic events, and extrapyramidal signs. Patients may present with symptoms later that include psychiatric manifestations, are slowly progressive, and may precede other neurologic or systemic features. Most of LSDs are autosomal recessive; however, a few are Xlinked with symptpmatic female carriers (e.g., Fabry disease). In most of them, the diagnosis is established by biochemical and/or molecular assays. In terms of management, diseasemodifying therapies include enzyme replacement, hematopoietic stem cell transplantation, and substrate reduction therapy. Patients and their families require genetic counseling regarding reproductive risks, disease prognosis, and therapeutic options. Investigations of disease molecular mechanisms provide insights into potential targets for the development of therapeutic strategies. Supportive care has been the key and essential for most LSDs, resulting in substantial improvement in quality of life of patients and families.