Olipudase alfa is indicated for the non-central nervous system manifestations of Acid sphingomyelinase deficiency (ASMD). Anaphylaxis is a very rare and life-threatening adverse reaction described for this drug. Here, we report the case of a 2-year-old boy affected by chronic neurovisceral ASMD who experienced signs of hypersensitivity reactions to olipudase alfa since the administered dose of 1 mg/kg during dose escalation and a proper anaphylactic reaction during the second administration of the target therapeutic dose of 3 mg/kg. The treatment was stopped for 15 weeks and then a 7-step desensitization protocol with the infused dose of 0.03 mg/kg was applied. Subsequent gradual dose escalation was resumed, successfully reaching the dose of 0.3 mg/kg. Moreover, biochemical, and radiological disease indexes, which were increased during treatment discontinuation, have gradually improved since the restart of treatment. However, at the second administration of the dose of 0.6 mg/kg, the patient experienced another adverse drug reaction with facial urticarial rash and bronchospasm, requiring the administration of adrenaline, methylprednisolone, and inhaled salbutamol. This case report highlights the need to customize the olipudase alfa desensitization protocol according to individual tolerance and raises the issue of achieving the established therapeutic target in the most sensitive children.
UNASSIGNED: We report a case of anaphylaxis to olipudase alfa in a child affected by chronic neurovisceral Acid sphingomyelinase deficiency (ASMD) and describe a 7-step desensitization procedure. This procedure, with the total administered dose of 0.03 mg/kg, followed by gradual dose escalation, allowed to reach the dose of 0.3 mg/kg without adverse reactions; however, at the second administration of the dose of 0.6 mg/kg our patient presented another adverse reaction suggesting the need of a different desensitization strategy.

BACKGROUND: This study aims to investigate the involvement of acid sphingomyelinase (ASM) in the pathology of dermatomyositis (DM), making it a potential therapeutic target for DM.
METHODS: Patients with DM and healthy controls (HCs) were included to assess the serum level and activity of ASM, and to explore the associations between ASM and clinical indicators. Subsequently, a myositis mouse model was established using ASM gene knockout and wild-type mice to study the significant role of ASM in the pathology and to assess the treatment effect of amitriptyline, an ASM inhibitor. Additionally, we investigated the potential treatment mechanism by targeting ASM both in vivo and in vitro.
RESULTS: A total of 58 DM patients along with 30 HCs were included. The ASM levels were found to be significantly higher in DM patients compared to HCs, with median (quartile) values of 2.63 (1.80-4.94) ng/mL and 1.64 (1.47-1.96) ng/mL respectively. The activity of ASM in the serum of DM patients was significantly higher than that in HCs. Furthermore, the serum levels of ASM showed correlations with disease activity and muscle enzyme levels. Knockout of ASM or treatment with amitriptyline improved the severity of the disease, rebalanced the CD4 T cell subsets Th17 and Treg, and reduced the production of their secreted cytokines. Subsequent investigations revealed that targeting ASM could regulate the expression of relevant transcription factors and key regulatory proteins.
CONCLUSIONS: ASM is involved in the pathology of DM by regulating the differentiation of naive CD4 + T cells and can be a potential treatment target.

Rituximab (RTX) resistance is a notable challenge in treating diffuse large B-cell lymphoma (DLBCL). β-Sitosterol (β-ST) is a plant sterol that has been found in a broad variety of fruits, spices, and medicinal plants. The antineoplastic properties of β-ST are established in various solid malignancies; however, its effect on DLBCL is uncharted. This study investigates the role of β-ST in DLBCL as well as the underlying mechanisms. Our findings indicated that β-ST impeded DLBCL cell proliferation in a concentration- and time-dependent manner. β-ST appeared to alter sphingolipid metabolism, facilitate acid sphingomyelinase (ASM) translocation to the plasma membrane, augment ceramide platforms through increased ceramide synthesis, and consequently induce apoptosis in DLBCL cells. Furthermore, we found that RTX initiated both apoptotic and survival pathways in vitro, with the former contingent on the transient activation of the ASM, and β-ST could amplify the anti-DLBCL efficacy of RTX by modulating ASM/Ceramide (Cer) signaling. Collectively, our findings elucidate the mechanistic role of β-ST in DLBCL and underscore its potential in amplifying the antineoplastic efficacy of RTX via ASM activation, proposing a potential avenue to improve the efficacy of RTX therapy.

Lysosomes are pivotal in cellular functions and disease, influencing cancer progression and therapy resistance with Acid Sphingomyelinase (ASM) governing their membrane integrity. Moreover, cation amphiphilic drugs (CADs) are known as ASM inhibitors and have anti-cancer activity, but the structural mechanisms of their interactions with the lysosomal membrane and ASM are poorly explored. Our study, leveraging all-atom explicit solvent molecular dynamics simulations, delves into the interaction of glycosylated ASM with the lysosomal membrane and the effects of CAD representatives, i.e., ebastine, hydroxyebastine and loratadine, on the membrane and ASM. Our results confirm the ASM association to the membrane through the saposin domain, previously only shown with coarse-grained models. Furthermore, we elucidated the role of specific residues and ASM-induced membrane curvature in lipid recruitment and orientation. CADs also interfere with the association of ASM with the membrane at the level of a loop in the catalytic domain engaging in membrane interactions. Our computational approach, applicable to various CADs or membrane compositions, provides insights into ASM and CAD interaction with the membrane, offering a valuable tool for future studies.

Japanese encephalitis virus (JEV) infection is considered a global public health emergency. Severe peripheral neuropathy caused by JEV infection has increased disability and mortality rates in recent years. Because there are very few therapeutic options for JEV infection, prompt investigations of the ability of clinically safe, efficacious and globally available drugs to inhibit JEV infection and ameliorate peripheral neuropathy are urgently needed. In this study, we found that high doses of intravenous immunoglobulin, a function inhibitor of acid sphingomyelinase (FIASMA), inhibited acid sphingomyelinase (ASM) and ceramide activity in the serum and sciatic nerve of JEV-infected rats, reduced disease severity, reversed electrophysiological and histological abnormalities, significantly reduced circulating proinflammatory cytokine levels, inhibited Th1 and Th17 cell proliferation, and suppressed the infiltration of inflammatory CD4 + cells into the sciatic nerve. It also maintained the peripheral nerve-blood barrier without causing severe clinical side effects. In terms of the potential mechanisms, ASM was found to participate in immune cell differentiation and to activate immune cells, thereby exerting proinflammatory effects. Therefore, immunoglobulin is a FIASMA that reduces abnormal immune responses and thus targets the ASM/ceramide system to treat peripheral neuropathy caused by JEV infection.

Acid sphingomyelinase (ASM) has been reported to increase tissue ceramide and thereby mediate hyperhomocysteinemia (hHcy)-induced glomerular nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NLRP3) inflammasome activation, inflammation, and sclerosis. In the present study, we tested whether somatic podocyte-specific silencing of Smpd1 gene (mouse ASM gene code) attenuates hHcy-induced NLRP3 inflammasome activation and associated extracellular vesicle (EV) release in podocytes and thereby suppresses glomerular inflammatory response and injury. In vivo, somatic podocyte-specific Smpd1 gene silencing almost blocked hHcy-induced glomerular NLRP3 inflammasome activation in Podocre (podocyte-specific expression of cre recombinase) mice compared with control littermates. By nanoparticle tracking analysis (NTA), floxed Smpd1 shRNA transfection was found to abrogate hHcy-induced elevation of urinary EV excretion in Podocre mice. In addition, Smpd1 gene silencing in podocytes prevented hHcy-induced immune cell infiltration into glomeruli, proteinuria, and glomerular sclerosis in Podocre mice. Such protective effects of podocyte-specific Smpd1 gene silencing were mimicked by global knockout of Smpd1 gene in Smpd1-/- mice. On the contrary, podocyte-specific Smpd1 gene overexpression exaggerated hHcy-induced glomerular pathological changes in Smpd1trg/Podocre (podocyte-specific Smpd1 gene overexpression) mice, which were significantly attenuated by transfection of floxed Smpd1 shRNA. In cell studies, we also confirmed that Smpd1 gene knockout or silencing prevented homocysteine (Hcy)-induced elevation of EV release in the primary cultures of podocyte isolated from Smpd1-/- mice or podocytes of Podocre mice transfected with floxed Smpd1 shRNA compared with WT/WT podocytes. Smpd1 gene overexpression amplified Hcy-induced EV secretion from podocytes of Smpd1trg/Podocre mice, which was remarkably attenuated by transfection of floxed Smpd1 shRNA. Mechanistically, Hcy-induced elevation of EV release from podocytes was blocked by ASM inhibitor (amitriptyline, AMI), but not by NLRP3 inflammasome inhibitors (MCC950 and glycyrrhizin, GLY). Super-resolution microscopy also showed that ASM inhibitor, but not NLRP3 inflammasome inhibitors, prevented the inhibition of lysosome-multivesicular body interaction by Hcy in podocytes. Moreover, we found that podocyte-derived inflammatory EVs (released from podocytes treated with Hcy) induced podocyte injury, which was exaggerated by T cell coculture. Interstitial infusion of inflammatory EVs into renal cortex induced glomerular injury and immune cell infiltration. In conclusion, our findings suggest that ASM in podocytes plays a crucial role in the control of NLRP3 inflammasome activation and inflammatory EV release during hHcy and that the development of podocyte-specific ASM inhibition or Smpd1 gene silencing may be a novel therapeutic strategy for treatment of hHcy-induced glomerular disease with minimized side effect.NEW & NOTEWORTHY In the present study, we tested whether podocyte-specific silencing of Smpd1 gene attenuates hyperhomocysteinemia (hHcy)-induced nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NLRP3) inflammasome activation and associated inflammatory extracellular vesicle (EV) release in podocytes and thereby suppresses glomerular inflammatory response and injury. Our findings suggest that acid sphingomyelinase (ASM) in podocytes plays a crucial role in the control of NLRP3 inflammasome activation and inflammatory EV release during hHcy. Based on our findings, it is anticipated that the development of podocyte-specific ASM inhibition or Smpd1 gene silencing may be a novel therapeutic strategy for treatment of hHcy-induced glomerular disease with minimized side effects.

Background: Gaucher disease is a lysosomal storage disorder caused by functional glucocerebrosidase enzyme deficiency. Hepatosplenomegaly and hematological complications are found in both Gaucher disease and Acid Sphingomyelinase Deficiency, which is caused by acid sphingomyelinase dysfunction. The possible overlap in clinical presentation can cause diagnostic errors in differential diagnosis. For this reason, in patients with an initial clinical suspicion of Gaucher disease, we aimed to carry out a parallel screening of acid sphingomyelinase and glucocerebrosidase. Methods: Peripheral blood samples of 627 patients were collected, and enzymatic activity analysis was performed on both glucocerebrosidase and acid sphingomyelinase. The specific gene was studied in samples with null or reduced enzymatic activity. Specific molecular biomarkers helped to achieve the correct diagnosis. Results: In 98.7% of patients, normal values of glucocerebrosidase activity excluded Gaucher disease. In 8 of 627 patients (1.3%), the glucocerebrosidase enzymatic activity assay was below the normal range, so genetic GBA1 analysis confirmed the enzymatic defect. Three patients (0.5%) had normal glucocerebrosidase activity, so they were not affected by Gaucher disease, and showed decreased acid sphingomyelinase activity. SMPD1 gene mutations responsible for Acid Sphingomyelinase Deficiency were found. The levels of specific biomarkers found in these patients further strengthened the genetic data. Conclusions: Our results suggest that in the presence of typical signs and symptoms of Gaucher disease, Acid Sphingomyelinase Deficiency should be considered. For this reason, the presence of hepatosplenomegaly, thrombocytopenia, leukocytopenia, and anemia should alert clinicians to analyze both enzymes by a combined screening. Today, enzyme replacement therapy is available for the treatment of both pathologies; therefore, prompt diagnosis is essential for patients to start accurate treatment and to avoid diagnostic delay.

Diallyl disulfide (DADS) is a well-known principal functional component derived from garlic (Allium sativum) that has various health benefits. Previously, we identified a 67-kDa laminin receptor, a receptor for oolong tea polyphenol oolonghomobisflavan B (OHBFB). However, its molecular mechanisms still remain to be elucidated. Here, we show that DADS synergistically enhanced the effect of the oolong tea polyphenol oolonghomobisflavan B (OHBFB), which induces apoptosis in acute myeloid leukemia (AML) cancer cells without affecting normal human peripheral blood mononuclear cells (PBMCs). The underlying mechanism of OHBFB-induced anti-AML effects involves the upregulation of the 67-kDa laminin receptor/endothelial nitric oxide synthase/cyclic guanosine monophosphate (cGMP)/protein kinase c delta (PKCδ)/acid sphingomyelinase (ASM)/cleaved caspase-3 signaling pathway. In conclusion, we show that the combination of OHBFB and DADS synergistically induced apoptotic cell death in AML cells through activation of 67LR/cGMP/PKCδ/ASM signaling pathway. Moreover, in this mechanism, we demonstrate DADS may reduce the enzyme activity of phosphodiesterase, which is a negative regulator of cGMP that potentiates OHBFB-induced AML apoptotic cell death without affecting normal PBMCs.

Thermal burn injuries can result in significant morbidity and mortality. The combination of ethanol intoxication with thermal burn injury results in increased morbidity through an exaggerated inflammatory response involving many organs. Recent studies have linked involvement of the lipid mediator Platelet-activating factor (PAF) in the pathology associated with intoxicated thermal burn injury (ITBI). The present studies tested the roles of PAF and the elevated levels of subcellular microvesicle particles (MVP) generated in response to ITBI in the subsequent multi-organ toxicity. First, thermal burn injury of HaCaT keratinocytes preincubated with ethanol resulted in augmented MVP release, which was blocked by inhibiting the PAF-generating enzyme cytosolic phospholipase A2 and the PAF receptor (PAFR). Second, ITBI of mice resulted in increased pro-inflammatory cytokine production and neutrophilic inflammation in multiple organs which were not present in mice deficient in PAFRs nor the MVP-generating enzyme acid sphingomyelinase (aSMase). Moreover, the increased bacterial translocation from the gut to mesenteric lymph nodes previously reported in murine ITBI was also dependent upon PAFR and aSMase. MVP released from ITBI-treated keratinocytes contained high levels of PAFR agonistic activity. Finally, use of topical aSMase inhibitor imipramine following ITBI attenuated the widespread organ inflammatory response of ITBI, suggesting a potential therapeutic for this condition. These studies provide evidence for PAF-enriched MVP generated in skin, which then act upon the gut PAFR resulting in bacterial translocation as the mechanism for the multi-organ dysfunction associated with ITBI. Inasmuch as aSMase inhibitors are widely available, these studies could result in effective treatments for ITBI.

BACKGROUND: Preclinical studies suggested that drugs that functionally inhibit acid sphingomyelinase (FIASMA)may enhance immune cell longevity and potentially offer protection against infections. Many antidepressants have shown FIASMA activity.
METHODS: We conducted a cohort study using primary-care data from the UK-based Clinical Practice Research Datalink (2000-2021). We assessed the association of composite diagnosed acute infections in new users of fluoxetine, sertraline, paroxetine, or venlafaxine aged 18-80 years compared to citalopram. We compared SARS-CoV-2 infections between groups in a secondary analysis. We estimated incidence rates (IR) and IR ratios (IRR) of acute infections in four pairwise comparisons using negative binomial regression. We applied propensity score (PS) fine stratification to control for confounding.
RESULTS: In the PS-weighted cohorts, we included 353,138 fluoxetine, 222,463 sertraline, 69,963 paroxetine, 32,608 venlafaxine, and between 515,996 and 516,583 new citalopram users. PS-weighted IRs ranged between 76.8 acute infections /1000 person-years (py) (sertraline) and 98.9 infections/1000 py (citalopram). We observed PS-weighted IRRs around unity for paroxetine (0.97, 95 % CI, 0.95-1.00), fluoxetine (0.94, 95 % CI, 0.92-0.95), and venlafaxine (0.90, 95 % CI, 0.87-0.94) vs citalopram. Reduced IRR for sertraline vs citalopram (0.84, 95 % CI, 0.82-0.85), became null within subgroups by cohort entry date. In the analysis of SARS-CoV-2 infection, no statistically relevant risk reduction was seen.
CONCLUSIONS: Analysis not limited to patients with diagnosed depression, possible underestimation of infection incidence, and unclear FIASMA activity of citalopram.
CONCLUSIONS: Fluoxetine, sertraline, paroxetine, and venlafaxine were not associated with a reduced risk of acute infection when compared with the presumably weak FIASMA citalopram.