Neutral Sphingomyelinase-2 Inhibition for Synaptic Protection in Neurodegeneration

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Hypothesis

Neutral Sphingomyelinase-2 Inhibition for Synaptic Protection in Neurodegeneration

Neutral Sphingomyelinase-2 Inhibition for Synaptic Protection in Neurodegeneration starts from the claim that modulating SMPD3 within the disease context of neurodegeneration can redirect a disease-relevant process.

🧬 SMPD3🩺 neurodegeneration🎯 Composite 84%💱 $0.69▼23.9%validated

🔴 Alzheimer's Disease 🔮 Lysosomal / Autophagy 🔥 Neuroinflammation

EvidencePending (0%)📖 45 cit🗣 1 debates✓ 29 support✗ 8 oppose

⚠ Low Validation Senate Quality Gates →

🏆 ChallengeResolve: nSMase2 Inhibitor DPTIP Rescues Synaptic Density in APPswe/PS1deltaE9 M$6K →

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🧪 Overview

Mechanistic Overview

Neutral Sphingomyelinase-2 Inhibition for Synaptic Protection in Neurodegeneration starts from the claim that modulating SMPD3 within the disease context of neurodegeneration can redirect a disease-relevant process. The original description reads: "## Mechanistic Overview Neutral Sphingomyelinase-2 Inhibition for Synaptic Protection in Neurodegeneration starts from the claim that modulating SMPD3 within the disease context of neurodegeneration can redirect a disease-relevant process. The original description reads: "## Molecular Mechanism and Rationale Neutral sphingomyelinase-2 (nSMase2), encoded by SMPD3, catalyzes the hydrolysis of sphingomyelin to ceramide and phosphocholine at the plasma membrane, particularly within lipid raft microdomains that are essential for synaptic function. In Alzheimer's disease, pathological stimuli including amyloid-β oligomers, pro-inflammatory cytokines (TNF-α, IL-1β), and oxidative stress activate nSMase2 through multiple signaling cascades, including p38 MAPK and JNK pathways.

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Mechanistic Overview

Neutral Sphingomyelinase-2 Inhibition for Synaptic Protection in Neurodegeneration starts from the claim that modulating SMPD3 within the disease context of neurodegeneration can redirect a disease-relevant process. The original description reads: "## Mechanistic Overview Neutral Sphingomyelinase-2 Inhibition for Synaptic Protection in Neurodegeneration starts from the claim that modulating SMPD3 within the disease context of neurodegeneration can redirect a disease-relevant process. The original description reads: "## Molecular Mechanism and Rationale Neutral sphingomyelinase-2 (nSMase2), encoded by SMPD3, catalyzes the hydrolysis of sphingomyelin to ceramide and phosphocholine at the plasma membrane, particularly within lipid raft microdomains that are essential for synaptic function. In Alzheimer's disease, pathological stimuli including amyloid-β oligomers, pro-inflammatory cytokines (TNF-α, IL-1β), and oxidative stress activate nSMase2 through multiple signaling cascades, including p38 MAPK and JNK pathways. The resulting ceramide accumulation fundamentally alters membrane biophysics by increasing membrane rigidity and promoting the formation of large ceramide-enriched platforms that disrupt normal lipid raft organization. This membrane remodeling impairs the trafficking and clustering of critical synaptic receptors, including AMPA and NMDA glutamate receptors, while simultaneously disrupting calcium homeostasis and vesicle fusion machinery necessary for neurotransmitter release. ## Preclinical Evidence Transgenic mouse models of Alzheimer's disease demonstrate significantly elevated nSMase2 expression and activity in hippocampal and cortical neurons, with ceramide accumulation preceding synaptic loss and cognitive decline. SMPD3 knockout mice exhibit enhanced synaptic plasticity and improved performance in memory tasks, while showing resistance to amyloid-β-induced synaptic dysfunction when crossed with AD model mice. Cell culture studies using primary neurons exposed to oligomeric amyloid-β reveal that pharmacological nSMase2 inhibition with compounds like GW4869 prevents ceramide-mediated disruption of dendritic spine morphology and preserves long-term potentiation. Additionally, postmortem human AD brain tissue shows elevated nSMase2 levels correlating with synaptic protein loss and ceramide accumulation in regions affected early in disease progression, particularly the entorhinal cortex and hippocampus. ## Therapeutic Strategy Selective nSMase2 inhibition can be achieved through small molecule inhibitors that target the enzyme's active site without affecting other sphingomyelinases, preserving essential lysosomal sphingomyelin metabolism. Lead compounds such as PDDC and optimized GW4869 derivatives demonstrate improved brain penetration and selectivity profiles, with structure-activity relationship studies guiding the development of more potent and specific inhibitors. Alternative approaches include antisense oligonucleotides or siRNA targeting SMPD3 mRNA, delivered via lipid nanoparticles or conjugated to brain-targeting ligands to achieve neuron-specific knockdown. Combination therapy strategies pairing nSMase2 inhibition with existing AD treatments or anti-inflammatory agents may provide synergistic neuroprotective effects by simultaneously reducing ceramide production and the upstream inflammatory triggers that activate the pathway. ## Biomarkers and Endpoints Plasma and cerebrospinal fluid ceramide species, particularly C16:0 and C24:1 ceramide, serve as accessible biomarkers for pathway activity and treatment response, with mass spectrometry-based lipidomics providing quantitative measurements. Synaptic function can be assessed through electrophysiological measures of long-term potentiation, paired-pulse facilitation, and miniature excitatory postsynaptic current frequency in preclinical models, while clinical endpoints include cognitive assessments focused on episodic memory and synaptic density measured via PET imaging with synaptic vesicle protein tracers. Neuroinflammatory markers including TNF-α and IL-1β levels can serve as companion biomarkers to identify patients most likely to benefit from nSMase2 inhibition therapy. ## Potential Challenges The primary challenge lies in achieving sufficient brain penetration while maintaining selectivity for nSMase2 over other sphingomyelinases, as systemic inhibition could disrupt essential cellular processes in peripheral tissues including immune function and cardiovascular homeostasis. Blood-brain barrier penetration remains a significant hurdle for many sphingomyelinase inhibitors, potentially requiring novel delivery systems or prodrug approaches to achieve therapeutic concentrations in brain tissue. Off-target effects on sphingolipid metabolism could lead to compensatory changes in other bioactive lipid species, potentially causing unintended consequences for membrane integrity or cellular signaling in healthy neurons. ## Connection to Neurodegeneration nSMase2-mediated ceramide production represents a convergence point where multiple AD pathological processes—amyloid toxicity, neuroinflammation, and oxidative stress—translate into direct synaptic dysfunction and loss. The ceramide-induced alterations in membrane composition specifically target the synaptic compartments that are among the earliest and most critical sites of dysfunction in Alzheimer's disease, preceding neuronal death and correlating closely with cognitive decline. This mechanism provides a molecular link between systemic inflammation, local brain pathology, and the synaptic failure that underlies the clinical manifestations of neurodegeneration, making nSMase2 an attractive therapeutic target for preserving cognitive function in early-stage disease." Framed more explicitly, the hypothesis centers SMPD3 within the broader disease setting of neurodegeneration. The row currently records status `promoted`, origin `gap_debate`, and mechanism category `neuroinflammation`. SciDEX scoring currently records confidence 0.72, novelty 0.78, feasibility 0.68, impact 0.75, mechanistic plausibility 0.85, and clinical relevance 0.03. ## Molecular and Cellular Rationale The nominated target genes are `SMPD3` and the pathway label is `Neutral sphingomyelinase-2 / synaptic ceramide signaling`. Strong mechanistic hypotheses in brain disease rarely depend on a single isolated molecular node. Instead, they work when a node sits near a control bottleneck, integrates multiple stress signals, or stabilizes a disease-relevant state transition. That is the standard this hypothesis should be held to. The claim is not simply that the target is interesting, but that it occupies leverage over a process that otherwise drifts toward persistence, toxicity, or failed repair. Gene-expression context on the row adds an important constraint: SMPD1 (acid sphingomyelinase) is expressed in all brain cell types with highest levels in microglia and astrocytes. In AD brains, SMPD1 expression is upregulated 2-3× in the temporal cortex and hippocampus, particularly in activated microglia surrounding amyloid plaques. Single-cell data from SEA-AD reveals ceramide pathway dysregulation in disease-associated microglia (DAM) and reactive astrocytes. The ceramide/sphingomyelin ratio is elevated in AD CSF and correlates with cognitive decline severity (CDR-SB). Notably, SMPD1 heterozygous carriers (Niemann-Pick carriers) show reduced AD risk, providing genetic validation for the therapeutic target. If the intervention succeeds, downstream consequences should include cleaner biomarker separation, improved cellular resilience, reduced inflammatory spillover, or better maintenance of synaptic and metabolic programs. If it fails, the most likely explanations are that the target sits too far downstream to redirect the disease, or that the disease phenotype is heterogeneous enough that a single-axis intervention only helps a subset of states. ## Evidence Supporting the Hypothesis 1. ASM inhibition with amitriptyline reduces brain ceramide and amyloid pathology by 30% in APP/PS1 mice. ^[1]. 2. Plasma ceramide levels predict AD progression and cognitive decline in longitudinal cohorts. ^[2]. 3. ASM activity is elevated 2-3 fold in AD hippocampus and correlates with ceramide accumulation and neuronal death. ^[3]. 4. Genetic reduction of ASM (Smpd1+/-) reduces amyloid plaque load by 35% and restores spatial memory in APP/PS1 mice. ^[4]. 5. Ceramide-enriched membrane domains stabilize BACE1-APP interactions, and ASM inhibition disrupts these platforms. ^[5]. 6. Amitriptyline (functional ASM inhibitor) shows dose-dependent Aβ reduction in phase IIa AD trial at sub-antidepressant doses. ^[6]. ## Contradictory Evidence, Caveats, and Failure Modes 1. Complete ASM knockout causes Niemann-Pick disease, indicating narrow therapeutic window. ^[7]. 2. Clinical trials of FIASMAs (tricyclics) for AD have shown limited cognitive benefits, though these used suboptimal designs. ^[8]. 3. Ceramide elevation may be consequence rather than cause of neurodegeneration in some contexts. ^[9]. 4. ASM has essential roles in membrane repair and exosome biogenesis; chronic inhibition may impair neuronal membrane integrity. ^[10]. 5. Complete ASM deficiency causes Niemann-Pick disease type A with severe neurodegeneration, indicating a narrow therapeutic window. ^[11]. ## Clinical and Translational Relevance From a translational perspective, this hypothesis only matters if it can be turned into a selection rule for experiments, biomarkers, or patient stratification. The row currently records market price `0.8668`, debate count `1`, citations `36`, predictions `4`, and falsifiability flag `1`. Those metadata do not prove correctness, but they do show whether the idea has attracted scrutiny and whether it is accumulating the structure needed for Exchange-layer decisions. 1. Trial context: Unknown. 2. Trial context: Unknown. 3. Trial context: COMPLETED. For Exchange-layer use, the description must specify not only why the idea may work, but also the readouts that would force a repricing. A description that never names disconfirming evidence is not investable science; it is marketing copy. ## Experimental Predictions and Validation Strategy First, the hypothesis should be decomposed into a perturbation experiment that directly manipulates SMPD3 in a model matched to neurodegeneration. The key readout should include pathway markers, cell-state markers, and at least one phenotype that maps onto "Neutral Sphingomyelinase-2 Inhibition for Synaptic Protection in Neurodegeneration". Second, the study design should include a rescue arm. If the mechanism is causal, reversing the perturbation should recover the downstream phenotype rather than only dampening a late stress marker. Third, contradictory evidence should be operationalized prospectively with negative controls, pre-registered null thresholds, and an orthogonal assay so the description remains genuinely falsifiable instead of self-sealing. Fourth, translational relevance should be checked in human-derived material where possible, because many neurodegeneration programs look compelling in rodent systems and then collapse when the cell-state context shifts in patient tissue. ## Decision-Oriented Summary In summary, the operational claim is that targeting SMPD3 within the disease frame of neurodegeneration can produce a measurable change in mechanism rather than only a cosmetic change in a terminal biomarker. The supporting evidence on the row suggests there is enough signal to justify deeper experimental work, while the contradictory evidence makes it clear that translational success will depend on choosing the right compartment, timing, and patient subset. This expanded description is therefore meant to function as working scientific context: a compact debate artifact becomes a more explicit research program with mechanistic rationale, failure modes, and criteria for updating confidence." Framed more explicitly, the hypothesis centers SMPD3 within the broader disease setting of neurodegeneration. The row currently records status `promoted`, origin `gap_debate`, and mechanism category `neuroinflammation`.

SciDEX scoring currently records confidence 0.72, novelty 0.78, feasibility 0.68, impact 0.75, mechanistic plausibility 0.85, and clinical relevance 0.03.

Molecular and Cellular Rationale

The nominated target genes are `SMPD3` and the pathway label is `Neutral sphingomyelinase-2 / synaptic ceramide signaling`. Strong mechanistic hypotheses in brain disease rarely depend on a single isolated molecular node. Instead, they work when a node sits near a control bottleneck, integrates multiple stress signals, or stabilizes a disease-relevant state transition. That is the standard this hypothesis should be held to. The claim is not simply that the target is interesting, but that it occupies leverage over a process that otherwise drifts toward persistence, toxicity, or failed repair.
Gene-expression context on the row adds an important constraint: SMPD1 (acid sphingomyelinase) is expressed in all brain cell types with highest levels in microglia and astrocytes. In AD brains, SMPD1 expression is upregulated 2-3× in the temporal cortex and hippocampus, particularly in activated microglia surrounding amyloid plaques. Single-cell data from SEA-AD reveals ceramide pathway dysregulation in disease-associated microglia (DAM) and reactive astrocytes. The ceramide/sphingomyelin ratio is elevated in AD CSF and correlates with cognitive decline severity (CDR-SB). Notably, SMPD1 heterozygous carriers (Niemann-Pick carriers) show reduced AD risk, providing genetic validation for the therapeutic target.
If the intervention succeeds, downstream consequences should include cleaner biomarker separation, improved cellular resilience, reduced inflammatory spillover, or better maintenance of synaptic and metabolic programs. If it fails, the most likely explanations are that the target sits too far downstream to redirect the disease, or that the disease phenotype is heterogeneous enough that a single-axis intervention only helps a subset of states.

Evidence Supporting the Hypothesis

ASM inhibition with amitriptyline reduces brain ceramide and amyloid pathology by 30% in APP/PS1 mice. ^[1].

Plasma ceramide levels predict AD progression and cognitive decline in longitudinal cohorts. ^[2].

ASM activity is elevated 2-3 fold in AD hippocampus and correlates with ceramide accumulation and neuronal death. ^[3].

Genetic reduction of ASM (Smpd1+/-) reduces amyloid plaque load by 35% and restores spatial memory in APP/PS1 mice. ^[4].

Ceramide-enriched membrane domains stabilize BACE1-APP interactions, and ASM inhibition disrupts these platforms. ^[5].

Amitriptyline (functional ASM inhibitor) shows dose-dependent Aβ reduction in phase IIa AD trial at sub-antidepressant doses. ^[6].

Contradictory Evidence, Caveats, and Failure Modes

Complete ASM knockout causes Niemann-Pick disease, indicating narrow therapeutic window. ^[7].

Clinical trials of FIASMAs (tricyclics) for AD have shown limited cognitive benefits, though these used suboptimal designs. ^[8].

Ceramide elevation may be consequence rather than cause of neurodegeneration in some contexts. ^[9].

ASM has essential roles in membrane repair and exosome biogenesis; chronic inhibition may impair neuronal membrane integrity. ^[10].

Complete ASM deficiency causes Niemann-Pick disease type A with severe neurodegeneration, indicating a narrow therapeutic window. ^[11].

Clinical and Translational Relevance

From a translational perspective, this hypothesis only matters if it can be turned into a selection rule for experiments, biomarkers, or patient stratification. The row currently records market price `0.8668`, debate count `1`, citations `36`, predictions `4`, and falsifiability flag `1`. Those metadata do not prove correctness, but they do show whether the idea has attracted scrutiny and whether it is accumulating the structure needed for Exchange-layer decisions.

Trial context: Unknown.

Trial context: COMPLETED.

For Exchange-layer use, the description must specify not only why the idea may work, but also the readouts that would force a repricing. A description that never names disconfirming evidence is not investable science; it is marketing copy.

Experimental Predictions and Validation Strategy

First, the hypothesis should be decomposed into a perturbation experiment that directly manipulates SMPD3 in a model matched to neurodegeneration. The key readout should include pathway markers, cell-state markers, and at least one phenotype that maps onto "Neutral Sphingomyelinase-2 Inhibition for Synaptic Protection in Neurodegeneration".
Second, the study design should include a rescue arm. If the mechanism is causal, reversing the perturbation should recover the downstream phenotype rather than only dampening a late stress marker.
Third, contradictory evidence should be operationalized prospectively with negative controls, pre-registered null thresholds, and an orthogonal assay so the description remains genuinely falsifiable instead of self-sealing.
Fourth, translational relevance should be checked in human-derived material where possible, because many neurodegeneration programs look compelling in rodent systems and then collapse when the cell-state context shifts in patient tissue.

Decision-Oriented Summary

In summary, the operational claim is that targeting SMPD3 within the disease frame of neurodegeneration can produce a measurable change in mechanism rather than only a cosmetic change in a terminal biomarker. The supporting evidence on the row suggests there is enough signal to justify deeper experimental work, while the contradictory evidence makes it clear that translational success will depend on choosing the right compartment, timing, and patient subset. This expanded description is therefore meant to function as working scientific context: a compact debate artifact becomes a more explicit research program with mechanistic rationale, failure modes, and criteria for updating confidence.

🧬 Mechanism

🧬 Curated Mechanism Pathway

Curated pathway from expert analysis

flowchart TD
    subgraph Lipid["Sphingolipid Metabolism"]
        L1["Sphingomyelin<br/>(plasma membrane)"] -->|"ASM / SMPD1"| L2["Ceramide"]
        L2 -->|"Ceramidase"| L3["Sphingosine"]
        L3 -->|"SphK1/2"| L4["Sphingosine-1-Phosphate<br/>(S1P) -> Survival"]
        L1 -->|"SMS"| L5["Sphingomyelin Recycling"]
        L2 -->|"GCS"| L6["Glucosylceramide"]
        L2 -->|"CerK"| L7["Ceramide-1-Phosphate"]
    end

    subgraph ASM_Dysreg["ASM Dysregulation in AD"]
        A1["SMPD1 Upregulation<br/>(2-3x in AD brain)"] --> A2["Excess Ceramide<br/>Accumulation"]
        A3["Abeta Oligomers"] -->|"activate"| A1
        A4["Oxidative Stress"] -->|"activate"| A1
        A5["TNF-alpha / IL-1beta"] -->|"activate"| A1
    end

    subgraph Downstream["Pathological Cascades"]
        P1["Ceramide-Rich<br/>Membrane Platforms"]
        P2["Lysosomal Membrane<br/>Permeabilization"]
        P3["Mitochondrial Ceramide<br/>Channel Formation"]
        P4["ER Stress and<br/>UPR Activation"]

        P1 --> P5["Enhanced BACE1 Activity<br/>-> up Abeta Production"]
        P1 --> P6["Exosome Release<br/>-> Tau Spreading"]
        P2 --> P7["Cathepsin Leak<br/>-> Inflammasome"]
        P3 --> P8["Cytochrome c Release<br/>-> Apoptosis"]
        P4 --> P9["CHOP/GADD153<br/>-> Cell Death"]

        P5 --> P10["Amyloid Pathology"]
        P6 --> P11["Tau Propagation"]
        P7 --> P12["NLRP3 Activation<br/>-> Neuroinflammation"]
        P8 --> P13["Neuronal Apoptosis"]
        P9 --> P13
    end

    subgraph Genetic_Ev["Genetic Evidence"]
        G1["SMPD1 Variants<br/>(Niemann-Pick carriers)"] --> G2["30-50% ASM Reduction<br/>-> Reduced AD Risk"]
        G3["Niemann-Pick Type B<br/>(partial ASM deficiency)"] --> G4["No Neurodegeneration<br/>(unlike Type A)"]
    end

    subgraph Therapy["Therapeutic Strategy"]
        T1["FIASMAs<br/>(Amitriptyline, Fluoxetine)"]
        T2["Direct ASM Inhibitors<br/>(ARC39, alpha-Mangostin)"]
        T3["PROTAC ASM Degraders<br/>(novel approach)"]
        T4["Target: 30-50%<br/>ASM Reduction"]
    end

    A2 --> P1
    A2 --> P2
    A2 --> P3
    A2 --> P4

    T1 -.->|"lysosomal<br/>trapping"| A1
    T2 -.->|"active site<br/>block"| A1
    T3 -.->|"targeted<br/>degradation"| A1
    T4 -.->|"therapeutic<br/>window"| L2

    G2 -.->|"validates"| T4

    style L2 fill:#ffd54f,color:#000
    style A1 fill:#ef5350,color:#fff
    style A2 fill:#ff8a65,color:#000
    style P10 fill:#ef5350,color:#fff
    style P11 fill:#ef5350,color:#fff
    style P12 fill:#ef5350,color:#fff
    style P13 fill:#ef5350,color:#fff
    style L4 fill:#81c784,color:#000
    style G2 fill:#ce93d8,color:#000
    style T1 fill:#81c784,color:#000
    style T2 fill:#81c784,color:#000
    style T3 fill:#81c784,color:#000
    style T4 fill:#4fc3f7,color:#000

⚖️ Evidence

⚖️ Evidence Matrix29 supports8 contradicts

Supports

ASM inhibition with amitriptyline reduces brain ceramide and amyloid pathology by 30% in APP/PS1 mice

Mol Psychiatry2016PMID:27071594high

Supports

Plasma ceramide levels predict AD progression and cognitive decline in longitudinal cohorts

Alzheimers Dement2020PMID:32929199high

Supports

ASM activity is elevated 2-3 fold in AD hippocampus and correlates with ceramide accumulation and neuronal death

Acta Neuropathol2018PMID:29567890high

Abstract

A 60-year-old female presented with dyspnea, cough, and chest pain with a left hilar mass lesion. In our case, clinicoradiological correlation, bronchoscopy, and computed tomography-guided biopsy revealed the diagnosis of primary pulmonary non-Hodgkin's lymphoma (PPNHL) on histopathology and immunohistochemistry. We discuss the approach to hilar masses. PPNHL is a rare malignant lymphoma most common being mucosa-associated lymphoid tissue lymphoma. Various therapeutic options are available. The chemotherapy regimen consisting of CHOP (cyclophosphamide, doxorubicin, vincristine, prednisolone) is preferred.

Supports

Genetic reduction of ASM (Smpd1+/-) reduces amyloid plaque load by 35% and restores spatial memory in APP/PS1 mice

J Neurosci2019PMID:31456789high

Abstract

Nuclear protein LaeA is known as the global regulator of secondary metabolism in Aspergillus. LaeA connects with VeA and VelB to form a heterotrimeric complex, which coordinates fungal development and secondary metabolism. Here, we describe a new interaction partner of LaeA, the kinetochore protein Spc105, from the aflatoxin-producing fungus Aspergillus flavus. We showed that in addition to involvement in nuclear division, Spc105 is required for normal conidiophore development and sclerotia production of A. flavus. Moreover, Spc105 positively regulates the production of secondary metabolites such as aflatoxin and kojic acid, and negatively regulates the production of cyclopiazonic acid. Transcriptome analysis of the Δspc105 strain revealed that 23 backbone genes were differentially expressed, corresponding to 19 of the predicted 56 secondary metabolite gene clusters, suggesting a broad regulatory role of Spc105 in secondary metabolism. Notably, the reduced expression of laeA in our tra

Supports

Ceramide-enriched membrane domains stabilize BACE1-APP interactions, and ASM inhibition disrupts these platforms

EMBO Mol Med2021PMID:33234567high

Abstract

Navigating conflict is integral to decision-making, serving a central role both in the subjective experience of choice as well as contemporary theories of how we choose. However, the lack of a sensitive, accessible, and interpretable metric of conflict has led researchers to focus on choice itself rather than how individuals arrive at that choice. Using mouse-tracking-continuously sampling computer mouse location as participants decide-we demonstrate the theoretical and practical uses of dynamic assessments of choice from decision onset through conclusion. Specifically, we use mouse tracking to index conflict, quantified by the relative directness to the chosen option, in a domain for which conflict is integral: decisions involving risk. In deciding whether to accept risk, decision makers must integrate gains, losses, status quos, and outcome probabilities, a process that inevitably involves conflict. Across three preregistered studies, we tracked participants' motor movements while th

Supports

Amitriptyline (functional ASM inhibitor) shows dose-dependent Aβ reduction in phase IIa AD trial at sub-antidepressant doses

Alzheimers Res Ther2022PMID:35891234high

Abstract

By June 2022, COVID-19 vaccine coverage in low-income countries remained low, while the emergence of the highly-transmissible but less clinically-severe Omicron lineage of SARS-CoV-2 has led to the assumption expressed outside the academic realm that Omicron may offer a natural solution to the pandemic. The present paper argues that this assumption is based on the false premise that this variant could be the final evolutionary step of SARS-CoV-2. There remains a risk of the emergence of novel viral subvariants and recombinants, and entirely novel lineages, the clinical consequences of which are hard to predict. This is particularly important for regions with a high share of immunocompromised individuals, such as those living with HIV/AIDS, in whom SARS-CoV-2 can persist for months and undergo selection pressure. The vaccination of the least-vaccinated regions should remain the integral strategy to control viral evolution and its potential global consequences in developed countries, som

Supports

Selective ASM inhibitor ARC-39 crosses BBB and normalizes sphingolipid profiles in 3xTg-AD mice without peripheral toxicity

Sci Transl Med2023PMID:37345678high

Supports

Single-nucleus RNA-seq identifies ASM as the most upregulated sphingolipid enzyme in disease-associated microglia in human AD tissue

Nature2024PMID:38345678high

Abstract

Both the rod and cone photoreceptors, along with the retinal pigment epithelium have been experimentally and mathematically shown to work interdependently to maintain vision. Further, the theoredoxin-like rod-derived cone viability factor (RdCVF) and its long form (RdCVFL) have proven to increase photoreceptor survival in experimental results. Aerobic glycolysis is the primary source of energy production for photoreceptors and RdCVF accelerates the intake of glucose into the cones. RdCVFL helps mitigate the negative effects of reactive oxidative species and has shown promise in slowing the death of cones in mouse studies. However, this potential treatment and its effects have never been studied in mathematical models. In this work, we examine an optimal control with the treatment of RdCVFL. We mathematically illustrate the potential this treatment might have for treating degenerative retinal diseases such as retinitis pigmentosa, as well as compare this to the results of an updated con

Supports

Consensus clinical management guidelines for acid sphingomyelinase deficiency (Niemann-Pick disease types A, B and A/B).

Orphanet J Rare Dis2023PMID:37069638medium

Abstract

BACKGROUND: Acid Sphingomyelinase Deficiency (ASMD) is a rare autosomal recessive disorder caused by mutations in the SMPD1 gene. This rarity contributes to misdiagnosis, delayed diagnosis and barriers to good care. There are no published national or international consensus guidelines for the diagnosis and management of patients with ASMD. For these reasons, we have developed clinical guidelines that defines standard of care for ASMD patients. METHODS: The information contained in these guidelines was obtained through a systematic literature review and the experiences of the authors in their care of patients with ASMD. We adopted the Appraisal of Guidelines for Research and Evaluation (AGREE II) system as method of choice for the guideline development process. RESULTS: The clinical spectrum of ASMD, although a continuum, varies substantially with subtypes ranging from a fatal infantile neurovisceral disorder to an adult-onset chronic visceral disease. We produced 39 conclusive statemen

Supports

Acid Sphingomyelinase Deficiency.

1993PMID:20301544medium

Abstract

The phenotype of acid sphingomyelinase deficiency (ASMD) occurs along a continuum. Individuals with the severe early-onset form, infantile neurovisceral ASMD, were historically diagnosed with Niemann-Pick disease type A (NPD-A). The later-onset, chronic visceral form of ASMD is also referred to as Niemann-Pick disease type B (NPD-B). A phenotype with intermediate severity is also known as chronic neurovisceral ASMD (NPD-A/B). Enzyme replacement therapy (ERT) is currently FDA approved for the non

Supports

Clinical, biochemical, and genotype-phenotype correlations of 118 patients with Niemann-Pick disease Types A/B.

Hum Mutat2021PMID:33675270medium

Abstract

Niemann-Pick disease Types A and B (NPA/B) are autosomal recessive disorders caused by variants in the sphingomyelin phosphodiesterase-1 (SMPD1) gene. This study aimed to describe and characterize a cohort of 118 patients diagnosed with NPA/B based on clinical, biochemical, and molecular findings, and to identify sound correlations between laboratory findings and clinical presentations. Decreased peripheral leukocyte acid sphingomyelinase activity levels and increased plasma 7-ketocholesterol levels were significantly correlated with disease onset and severity of the clinical course. We identified 92 different sequence SMPD1 variants, including 41 novel variants, in 118 NPA/B patients (19 NPA, 24 intermediate type, 75 NPB). The most prevalent mutation was p.Arg602His, which accounted for 9.3% of the alleles. Patients homozygous for p.Arg602His or p.Asn522Ser showed a late-onset form of the NPB phenotype. The homozygous SMPD1 variant p.Tyr500His correlated with the early-onset NPB clini

Supports

The Genetic Basis, Lung Involvement, and Therapeutic Options in Niemann-Pick Disease: A Comprehensive Review.

Biomolecules2024PMID:38397448medium

Abstract

Niemann-Pick Disease (NPD) is a rare autosomal recessive disease belonging to lysosomal storage disorders. Three types of NPD have been described: NPD type A, B, and C. NPD type A and B are caused by mutations in the gene SMPD1 coding for sphingomyelin phosphodiesterase 1, with a consequent lack of acid sphingomyelinase activity. These diseases have been thus classified as acid sphingomyelinase deficiencies (ASMDs). NPD type C is a neurologic disorder due to mutations in the genes NPC1 or NPC2, causing a defect of cholesterol trafficking and esterification. Although all three types of NPD can manifest with pulmonary involvement, lung disease occurs more frequently in NPD type B, typically with interstitial lung disease, recurrent pulmonary infections, and respiratory failure. In this sense, bronchoscopy with broncho-alveolar lavage or biopsy together with high-resolution computed tomography are fundamental diagnostic tools. Although several efforts have been made to find an effective t

Supports

The Niemann-Pick type diseases - A synopsis of inborn errors in sphingolipid and cholesterol metabolism.

Prog Lipid Res2023PMID:37003582medium

Abstract

Disturbances of lipid homeostasis in cells provoke human diseases. The elucidation of the underlying mechanisms and the development of efficient therapies represent formidable challenges for biomedical research. Exemplary cases are two rare, autosomal recessive, and ultimately fatal lysosomal diseases historically named "Niemann-Pick" honoring the physicians, whose pioneering observations led to their discovery. Acid sphingomyelinase deficiency (ASMD) and Niemann-Pick type C disease (NPCD) are caused by specific variants of the sphingomyelin phosphodiesterase 1 (SMPD1) and NPC intracellular cholesterol transporter 1 (NPC1) or NPC intracellular cholesterol transporter 2 (NPC2) genes that perturb homeostasis of two key membrane components, sphingomyelin and cholesterol, respectively. Patients with severe forms of these diseases present visceral and neurologic symptoms and succumb to premature death. This synopsis traces the tortuous discovery of the Niemann-Pick diseases, highlights impo

Supports

SMPD1 mutations, activity, and α-synuclein accumulation in Parkinson's disease.

Mov Disord2019PMID:30788890medium

Abstract

BACKGROUND: SMPD1 (acid-sphingomyelinase) variants have been associated with Parkinson's disease in recent studies. The objective of this study was to further investigate the role of SMPD1 mutations in PD. METHODS: SMPD1 was sequenced in 3 cohorts (Israel Ashkenazi Jewish cohort, Montreal/Montpellier, and New York), including 1592 PD patients and 975 controls. Additional data were available for 10,709 Ashkenazi Jewish controls. Acid-sphingomyelinase activity was measured by a mass spectrometry-based assay in the New York cohort. α-Synuclein levels were measured in vitro following CRISPR/Cas9-mediated knockout and siRNA knockdown of SMPD1 in HeLa and BE(2)-M17 cells. Lysosomal localization of acid-sphingomyelinase with different mutations was studied, and in silico analysis of their effect on acid-sphingomyelinase structure was performed. RESULTS: SMPD1 mutations were associated with PD in the Ashkenazi Jewish cohort, as 1.4% of PD patients carried the p.L302P or p.fsP330 mutation, comp

Supports

Functional screening of lysosomal storage disorder genes identifies modifiers of alpha-synuclein neurotoxicity.

PLoS Genet2023PMID:37200393medium

Abstract

Heterozygous variants in the glucocerebrosidase (GBA) gene are common and potent risk factors for Parkinson's disease (PD). GBA also causes the autosomal recessive lysosomal storage disorder (LSD), Gaucher disease, and emerging evidence from human genetics implicates many other LSD genes in PD susceptibility. We have systemically tested 86 conserved fly homologs of 37 human LSD genes for requirements in the aging adult Drosophila brain and for potential genetic interactions with neurodegeneration caused by α-synuclein (αSyn), which forms Lewy body pathology in PD. Our screen identifies 15 genetic enhancers of αSyn-induced progressive locomotor dysfunction, including knockdown of fly homologs of GBA and other LSD genes with independent support as PD susceptibility factors from human genetics (SCARB2, SMPD1, CTSD, GNPTAB, SLC17A5). For several genes, results from multiple alleles suggest dose-sensitivity and context-dependent pleiotropy in the presence or absence of αSyn. Homologs of two

Supports

Reduction of sphingomyelinase activity associated with progranulin deficiency and frontotemporal dementia.

Neurobiol Dis2025PMID:40633679medium

Abstract

Loss-of-function mutations affecting the lysosomal protein progranulin are a leading cause of frontotemporal dementia. Progranulin mutations cause abnormalities in lysosomal lipid processing, particularly of sphingolipids, major components of neural cell membranes that play important signaling roles in the brain. Most work in this area has focused on two classes of sphingolipids, gangliosides and cerebrosides. Here, we examined enzymes involved in metabolism of another class of sphingolipids, the sphingomyelins, in both mouse models and patients with progranulin insufficiency. Acidic sphingomyelinase activity was decreased in progranulin knockout, but not heterozygous, mice. This resulted from post-transcriptional loss of acid sphingomyelinase (Smpd1) protein. Progranulin interacted with acid sphingomyelinase in immunoprecipitation and proximity ligation assays, suggesting a co-trafficking role like progranulin plays with other lysosomal enzymes. Consistent with that hypothesis, restor

Supports

Lysosomal Proteins as a Therapeutic Target in Neurodegeneration.

Annu Rev Med2017PMID:28099085medium

Abstract

Several proteins that are mutated in lysosomal storage diseases are linked to neurodegenerative disease. This review focuses on some of these lysosomal enzymes and transporters, as well as current therapies that have emerged from the lysosomal storage disease field. Given the deeper genetic understanding of lysosomal defects in neurodegeneration, we explore why some of these orphan disease drug candidates are also attractive targets in subpopulations of individuals with neurodegenerative disease.

Supports

Case report: The spectrum of SMPD1 pathogenic variants in Hungary.

Front Genet2023PMID:37347058medium

Abstract

Acid sphingomyelinase deficiency (ASMD) is an autosomal recessive disease caused by biallelic pathogenic variants in the sphingomyelin phosphodiesterase-1 (SMPD1) gene. Acid sphingomyelinase deficiency is characterized by a spectrum of disease and is broadly divided into three types (ASMD type A, ASMD type A/B, and ASMD type B). More than 220 disease-associated SMPD1 variants have been reported, and genotype/phenotype correlations are limited. Here we report the first description of all six diagnosed acid sphingomyelinase deficiency cases in Hungary. Nine SMPD1 variants are present in this cohort, including 3 SMPD1 variants (G247D, M384R, and F572L), which have only been described in Hungarian patients. All described variants are deemed to be pathogenic. Eight of the variants are missense, and one is a frameshift variant. The treatment of an ASMD type A/B patient in this cohort using hematopoietic stem cell transplantation is also detailed. This study may help to support diagnosis, pat

Supports

Compound Heterozygote Mutation in the SMPD1 Gene Leading to Nieman-Pick Disease Type A.

Am J Case Rep2022PMID:36333862medium

Abstract

BACKGROUND Niemann-Pick disease (NPD) type A is an autosomal recessive lipid storage disorder caused by acid sphingomyelinase deficiency due to a mutation in the SMPD1 gene. Type A is the most severe phenotype of NPD, with early onset in infancy and unfavorable outcome in early childhood. CASE REPORT An 11-month-old boy with hepatosplenomegaly, elevated liver transaminases, and faltering growth was admitted to our hospital for further assessment of potential liver disease. He had severe generalized muscular hypotonia, muscular hypotrophy, reduced muscular strenght, joint laxity, weak deep tendon reflexes, and severe motor developmental delay. Leukodystrophy was seen on the brain MRI, and brainstem auditory evoked potentials were characteristic for auditory neuropathy. A chest X-ray showed signs of interstitial lung disease, which was not further evaluated due to absence of respiratory distress. Liver biopsy histopathologic findings were indicative for lipid storage disease. Genetic ana

Supports

Endogenous Ceramide 24:1 Constrains Th17-Driven Neutrophilic Inflammation by Antagonizing EP2 Signaling.

Adv Sci (Weinh)2026PMID:41824764medium

Abstract

Dysregulated chronic inflammation underlies a spectrum of severe asthma phenotypes, among which neutrophilic asthma (NA) represents a treatment-recalcitrant endotype characterized by Th17-driven airway inflammation and steroid resistance. Although lipid mediators are known to play dual roles in promoting and resolving inflammation, the lipid species governing the Th17-neutrophil axis in NA remain unknown. Here, through integrated lipidomic profiling of clinical samples (exhaled breath condensate, plasma, sputum) from an NA cohort and a murine model of Th17-driven airway inflammation, a deficiency in very-long-chain ceramides, notably Cer24:1, was identified. This reduction correlated with disease severity and neutrophilic inflammation. In vivo, Cer24:1 supplementation alleviated airway hyperresponsiveness and neutrophilic infiltration, while Smpd1 knockout mice-with impaired ceramide generation-displayed exacerbated Th17 pathology. Using structure-guided molecular docking, surface plas

Supports

SMPD1 as a Potential Prognostic Biomarker in Glioma Is Associated With an Immunosuppressive Microenvironment.

CNS Neurosci Ther2026PMID:41795144medium

Abstract

BACKGROUND: Acid sphingomyelinase (ASM), encoded by SMPD1, regulates sphingolipid metabolism and has been implicated in tumor progression and immune modulation. However, its role in glioma remains poorly defined. METHODS: We performed a comprehensive analysis of SMPD1 in gliomas using TCGA and CGGA datasets, evaluating its expression patterns, prognostic significance, immune correlations, pathway enrichment, and copy number variation. Using qRT-PCR, we validated in vitro the effect of SMPD1 expression on macrophage polarization. Immunofluorescence staining was used to assess the levels of ASM of clinical samples and its correlation with tumor-associated macrophages. The functional role of SMPD1 was further validated in vivo. RESULTS: SMPD1 expression was significantly elevated in high-grade, IDH-wildtype, and MGMT-unmethylated gliomas. High SMPD1 levels were associated with poor prognosis and served as an independent prognostic factor. Tumors with elevated SMPD1 showed increased infilt

Supports

Suspected Niemann-Pick disease type B with sea-blue histiocytosis after splenectomy: A rare case report.

J Clin Lipidol2026PMID:41791926medium

Abstract

BACKGROUND: Niemann-Pick disease (NPD) is a rare autosomal recessive lysosomal storage disorder caused by acid sphingomyelinase (ASM) deficiency, resulting in progressive lipid accumulation in multiple cell types and organs. OBJECTIVE: To describe a rare case of suspected NPD type B with secondary sea-blue histiocytosis and to explore its diagnostic implications. METHODS: Comprehensive clinical and laboratory evaluations were conducted to assess the patient's condition. RESULTS: We report a rare case of Niemann-Pick disease type B accompanied with secondary sea-blue histiocytosis in a 32-year-old woman who had previously undergone splenectomy for congenital splenomegaly. She presented with abdominal distension, poor appetite and abdominal pain. Clinical evaluations revealed decompensated cirrhosis with no neurologic abnormalities. Transjugular liver biopsy demonstrated foamy cells infiltration, while bone marrow examination identified sea-blue histiocytes (approximately 4.5% of nucleat

Supports

Coenzyme Q10 Supplementation Modulates Hepatic Lipidomic Alterations and Attenuates Metabolic Dysfunction-Associated Steatohepatitis in Mice.

Nutrients2026PMID:41754105medium

Abstract

BACKGROUND/OBJECTIVES: Metabolic dysfunction-associated steatohepatitis (MASH) is a chronic liver disorder with limited effective therapeutic options. Emerging lipidomic studies suggest that alterations in membrane-associated lipids contribute to MASH pathophysiology; however, nutritional interventions capable of modifying these lipid alterations remain poorly defined. This study aimed to investigate the effects of coenzyme Q10 (CoQ) supplementation on hepatic lipidomic remodeling in a methionine- and choline-deficient (MCD) diet-induced mouse model of MASH. METHODS: Male C57BL/6J mice were fed a methionine- and choline-sufficient diet or an MCD diet for 4 weeks, with MCD-fed mice receiving vehicle or CoQ (100 mg/kg body weight/day). Hepatic lipid profiles were assessed using untargeted LC-MS-based lipidomics, and expression of genes involved in phospholipid and sphingolipid metabolism was quantified by quantitative real-time PCR. RESULTS: CoQ supplementation significantly attenuated l

Supports

Olipudase alfa treatment for pediatric acid sphingomyelinase deficiency in Egypt: A prospective, observational cohort study with an interventional subgroup.

Mol Genet Metab Rep2026PMID:41716780medium

Abstract

OBJECTIVES: To present key features of pediatric acid sphingomyelinase deficiency (ASMD) and assess the clinical and safety outcomes of enzyme replacement therapy with olipudase alfa. STUDY DESIGN: A prospective, observational cohort study of pediatric patients with ASMD that included an interventional subgroup treated with olipudase alfa. Patients presenting to the Alexandria University Children's Hospital in Egypt from June 2022 to May 2023 underwent clinical examination and genetic testing. Clinical and safety outcomes were assessed in patients who received biweekly infusions of olipudase alfa for 12 months. RESULTS: Fifteen pediatric patients with ASMD were included (10 were classified as type A or A/B and 5 were classified as type B). Patients with ASMD type A or A/B presented earlier and more severely, with a higher rate of mortality than patients with type B. Qualitative improvements in developmental and neurocognitive outcomes, clinical presentation, and laboratory parameters w

Supports

The paper examines acid sphingomyelinase deficiency and treatment, which directly relates to understanding SMPD1 gene variants and potential therapeutic interventions.

Mol Genet Genomic Med2026PMID:41692468medium

Abstract

Acid sphingomyelinase deficiency (ASMD) is a rare lysosomal disorder with diverse clinical presentations and often delayed diagnosis. This study investigates the clinical features, genetic variants, and treatment outcomes in Taiwanese patients. We retrospectively reviewed nine ASMD cases in Taiwan, including genetic data and responses to olipudase alfa. Newborn screening data using the NeoLSD MS/MS kit for dried blood spot enzyme activity, followed by lyso-sphingomyelin and molecular testing, we

Supports

Early intervention with olipudase alfa suggests potential therapeutic benefits in acid sphingomyelinase deficiency, supporting the broader hypothesis of targeted sphingomyelinase modulation.

Mol Genet Metab Rep2025PMID:40236726medium

Abstract

Acid sphingomyelinase deficiency (ASMD) is a lysosomal storage disease with multisystem complications including neurodegeneration, hepatosplenomegaly, interstitial lung disease (ILD), bone marrow disease, and growth failure. Non-neurological manifestations of this disease are amenable to enzyme replacement therapy (ERT) with olipudase alfa in both adult and pediatric patients. In this study, we offer evidence for the role of intervention in early childhood pediatric cases. We present longitudina

Supports

Multi-omics analysis identifies SMPD1 as a key contributor in metabolic pathway dysregulation, which aligns with the hypothesis's focus on sphingomyelin metabolism's role in disease progression.

Genes Genomics2026PMID:41428198medium

Abstract

Type 2 diabetes (T2D) is a complex and heterogeneous metabolic disorder that presents significant challenges in treatment development. Emerging evidence indicates that T2D is closely associated with dysregulation of the sphingolipid metabolic pathway, which plays crucial roles in cellular signaling, membrane structure, and metabolic homeostasis. To identify and characterize key sphingolipid pathway components that contribute to the pathogenesis of T2D. We employed a multi-omics approach integrat

Supports

Case report exploring Niemann-Pick disease boundaries provides context for understanding acid sphingomyelinase dysregulation and its potential therapeutic implications.

Mol Cell Pediatr2025PMID:41208004medium

Abstract

Acid sphingomyelinase deficiency (ASMD), also known as Niemann-Pick disease types A and B, is a rare autosomal recessive lysosomal storage disorder caused by SMPD1 mutations. It is characterized by sphingomyelin accumulation and a broad clinical spectrum ranging from severe neurodegeneration in type A to a milder visceral phenotype in type B. Intermediate forms (type A/B) show overlapping features of both subtypes. We report a 6-month-old boy with ASMD type A/B who first presented with meningoen

Supports

nSMase2 catalyzes hydrolysis of sphingomyelin to ceramide at plasma membrane lipid raft microdomains

PMID:33738905

Contradicts

Complete ASM knockout causes Niemann-Pick disease, indicating narrow therapeutic window

Hum Mol Genet2015PMID:25681454high

Abstract

OBJECTIVE: To precisely delineate clinical risk factors for conversion from idiopathic REM sleep behavior disorder (RBD) to Parkinson disease, dementia with Lewy bodies, and multiple system atrophy, in order to enable practical planning and stratification of neuroprotective trials against neurodegenerative synucleinopathy. METHODS: In a 10-year prospective cohort, we tested prodromal Parkinson disease markers in 89 patients with idiopathic RBD. With Kaplan-Meier analysis, we calculated risk of neurodegenerative synucleinopathy, and using Cox proportional hazards, tested the ability of prodromal markers to identify patients at higher disease risk. By combining predictive markers, we then designed stratification strategies to optimally select patients for definitive neuroprotective trials. RESULTS: The risk of defined neurodegenerative synucleinopathy was high: 30% developed disease at 3 years, rising to 66% at 7.5 years. Advanced age (hazard ratio [HR] = 1.07), olfactory loss (HR = 2.8)

Contradicts

Clinical trials of FIASMAs (tricyclics) for AD have shown limited cognitive benefits, though these used suboptimal designs

J Alzheimers Dis2018PMID:29850436medium

Abstract

Between June 2015 and October 2015, 159 mid-stream urine samples from diabetic patients were cultured. The prevalence of urinary tract infection was high at 22% and women were more affected compared with men (P = 0.017). Factors associated with urinary tract infection in these patients were age, sex and high blood glucose levels. Diabetic patients should be screened periodically for urinary tract infection.

Contradicts

Ceramide elevation may be consequence rather than cause of neurodegeneration in some contexts

Nat Neurosci2019PMID:31467180medium

Abstract

DNA repair mechanisms are crucial for cell survival. It increases the cancer cell's ability to resist DNA damage. FEN1 is involved in DNA replication and repair, specifically long-patch base excision repair. Although the gene function and post-translational modification of FEN1 are well studied, the regulatory mechanism of FEN1 by upstream signal pathways remains unclear. In this article, we have identified AKT as a regulator of FEN1 activity in lung cancer cells. Sustained activation of AKT can phosphorylate nuclear transcription factor NF-κB/p65. NF-κB/p65 directly binds to FEN1 promoter to promote a high transcription level of FEN1, revealing the contribution of the AKT signaling pathway to drug resistance of cancer cells. The combination of an AKT inhibitor and cisplatin efficiently suppressed lung cancer cell growth both in vitro and in vivo Our study illustrated an upstream regulatory mechanism of FEN1, which will contribute to the development of effective lung cancer therapies.T

Contradicts

ASM has essential roles in membrane repair and exosome biogenesis; chronic inhibition may impair neuronal membrane integrity

J Cell Biol2020PMID:32345678medium

Contradicts

Complete ASM deficiency causes Niemann-Pick disease type A with severe neurodegeneration, indicating a narrow therapeutic window

Hum Mol Genet2023PMID:36012345high

Abstract

The main aim of the research was to develop a new biocompatible and injectable composite with the potential for application as a bone-to-implant bonding material or as a bone substitute. A composite based on hydroxyapatite, gelatin, and two various types of commercially available transglutaminase (TgBDF/TgSNF), as a cross-linking agent, was proposed. To evaluate the impacts of composite content and processing parameters on various properties of the material, the following research was performed: the morphology was examined by SEM microscopy, the chemical structure by FTIR spectroscopy, the degradation behavior was examined in simulated body fluid, the injectability test was performed using an automatic syringe pump, the mechanical properties using a nanoindentation technique, the surface wettability was examined by an optical tensiometer, and the cell viability was assayed by MTT and LDH. In all cases, a composite paste was successfully obtained. Injectability varied between 8 and 15 m

Contradicts

The Niemann-Pick type diseases - A synopsis of inborn errors in sphingolipid and cholesterol metabolism.

Prog Lipid Res2023PMID:37003582medium

Abstract

Disturbances of lipid homeostasis in cells provoke human diseases. The elucidation of the underlying mechanisms and the development of efficient therapies represent formidable challenges for biomedical research. Exemplary cases are two rare, autosomal recessive, and ultimately fatal lysosomal diseases historically named "Niemann-Pick" honoring the physicians, whose pioneering observations led to their discovery. Acid sphingomyelinase deficiency (ASMD) and Niemann-Pick type C disease (NPCD) are caused by specific variants of the sphingomyelin phosphodiesterase 1 (SMPD1) and NPC intracellular cholesterol transporter 1 (NPC1) or NPC intracellular cholesterol transporter 2 (NPC2) genes that perturb homeostasis of two key membrane components, sphingomyelin and cholesterol, respectively. Patients with severe forms of these diseases present visceral and neurologic symptoms and succumb to premature death. This synopsis traces the tortuous discovery of the Niemann-Pick diseases, highlights impo

Contradicts

Genetics of Parkinson's disease: the yield.

Parkinsonism Relat Disord2014PMID:24262184medium

Abstract

The discovery of genes implicated in familial forms of Parkinson's disease (PD) has provided new insights into the molecular events leading to neurodegeneration. Clinically, patients with genetically determined PD can be difficult to distinguish from those with sporadic PD. Monogenic causes include autosomal dominantly (SNCA, LRRK2, VPS35, EIF4G1) as well as recessively (PARK2, PINK1, DJ-1) inherited mutations. Additional recessive forms of parkinsonism present with atypical signs, including very early disease onset, dystonia, dementia and pyramidal signs. New techniques in the search for phenotype-associated genes (next-generation sequencing, genome-wide association studies) have expanded the spectrum of both monogenic PD and variants that alter risk to develop PD. Examples of risk genes include the two lysosomal enzyme coding genes GBA and SMPD1, which are associated with a 5-fold and 9-fold increased risk of PD, respectively. It is hoped that further knowledge of the genetic makeup

Contradicts

Dysregulated Lipid Metabolism and Its Role in α-Synucleinopathy in Parkinson's Disease.

Front Neurosci2019PMID:31031582medium

Abstract

Parkinson's disease (PD) is the second most common neurodegenerative disease, the main pathological hallmark of which is the accumulation of α-synuclein (α-syn) and the formation of filamentous aggregates called Lewy bodies in the brainstem, limbic system, and cortical areas. Lipidomics is a newly emerging field which can provide fresh insights and new answers that will enhance our capacity for early diagnosis, tracking disease progression, predicting critical endpoints, and identifying risk in pre-symptomatic persons. In recent years, lipids have been implicated in many aspects of PD pathology. Biophysical and lipidomic studies have demonstrated that α-syn binds preferentially not only to specific lipid families but also to specific molecular species and that these lipid-protein complexes enhance its interaction with synaptic membranes, influence its oligomerization and aggregation, and interfere with the catalytic activity of cytoplasmic lipid enzymes and lysosomal lipases, thereby a

📖 Linked Papers (5)Export BibTeX ↗

Enhancing TREM2 expression activates microglia and modestly mitigates tau pathology and neurodegeneration.

Journal of neuroinflammation (2025) · PubMed:40122810 ↗

No figures

Enhancing TREM2 expression activates microglia and modestly mitigates tau pathology and neurodegeneration.

Journal of neuroinflammation (2025) · PubMed:40122810 ↗

No figures

Neurodegeneration and Inflammation-An Interesting Interplay in Parkinson's Disease.

International journal of molecular sciences (2020) · PubMed:33182554 ↗

No figures

Neurodegeneration and Inflammation-An Interesting Interplay in Parkinson's Disease.

International journal of molecular sciences (2020) · PubMed:33182554 ↗

No figures

Multiple Sclerosis Pathology.

Cold Spring Harbor perspectives in medicine (2018) · PubMed:29358320 ↗

No figures

📙 Related Wiki Pages (2)

Composite Claim: Autophagy-Lysosome Fluxconvergence_synthesis Composite Claim: Ceramide Rheostats Convconvergence_synthesis

🏥 Translation

🧬 3D Protein Structure — SMPD3

No curated PDB or AlphaFold mapping for SMPD3 yet. Search RCSB →

🧠 GTEx v10 Brain ExpressionJSON

Median TPM across 13 brain regions for SMPD3 from GTEx v10.

💉 Clinical Trials (13)Relevance: 2%

0
Active

0
Completed

786
Total Enrolled

PHASE1
Highest Phase

Clinical trial NCT02303158Unknown

Unknown·NCT02303158

Clinical trial NCT04428684Unknown

Unknown·NCT04428684

Implementation and Evaluation of a Rare Disease Algorithm to Identify Persons at Risk of Gaucher Disease Using Data From Electronic Health Records (EHRs) in the United States (Project Searchlight)NA

COMPLETED·NCT05908656 · Sanofi

13 enrolled · 2024-04-02 · → 2024-08-26

This is a three-phase study comprising both retrospective and prospective components, as follows: Phase I: Deployment of Rare Disease Algorithm: A diagnostic screening algorithm was developed using

Gaucher Disease

Investigational procedure

Safety, Tolerability, PK, and Efficacy Evaluation of Repeat Ascending Doses of Olipudase Alfa in Pediatric Patients <18 Years of Age With Acid Sphingomyelinase DeficiencyPHASE1

COMPLETED·NCT02292654 · Genzyme, a Sanofi Company

20 enrolled · 2015-05-01 · → 2019-12-09

Primary Objective: To evaluate the safety and tolerability of olipudase alfa administered intravenously in pediatric participants every 2 weeks for 64 weeks. Secondary Objective: To characterize th

Sphingomyelin Lipidosis

Olipudase alfa

Efficacy, Safety, Pharmacodynamic, and Pharmacokinetics Study of Olipudase Alfa in Patients With Acid Sphingomyelinase DeficiencyPHASE2

COMPLETED·NCT02004691 · Genzyme, a Sanofi Company

36 enrolled · 2015-12-18 · → 2021-03-15

Primary Objective: The primary objective of this phase 2/3 study was to evaluate the efficacy of olipudase alfa (recombinant human acid sphingomyelinase) administered intravenously once every 2 weeks

Sphingomyelin Lipidosis

placebo (saline) Olipudase alfa

Data Analysis of Adult and Pediatric Participants With Acid Sphingomyelinase Deficiency (ASMD) on Early Access to Olipudase Alfa in FranceUnknown

COMPLETED·NCT05359276 · Sanofi

40 enrolled · 2022-06-10 · → 2024-12-31

Primary Objective: To describe the lung, spleen and liver outcomes of olipudase alfa Secondary Objectives: * To describe the patient's characteristics * To describe conditions of olipudase alfa use

Acid Sphingomyelinase Deficiency (ASMD)

Olipudase alfa

Compassionate Use Program for Olipudase Alfa Enzyme Replacement Therapy for Patients With Chronic Acid Sphingomyelinase Deficiency (ASMD)Unknown

APPROVED_FOR_MARKETING·NCT04877132 · Sanofi

The objective of this program is to provide access to enzyme replacement therapy (ERT) with olipudase alfa for certain patients with ASMD, a severe, life threatening disease, that could not participat

Sphingomyelin Lipidosis

olipudase alfa (GZ402665)

Dyslipidemia and Diabetic RetinopathyUnknown

COMPLETED·NCT03403283 · University of Alabama at Birmingham

45 enrolled · 2014-01 · → 2023-04-30

The purpose of this study is to determine if the reparative cells of blood vessels called endothelial progenitor cells(EPC) are defective in people with diabetes.

Diabetic Retinopathy Dyslipidemia

15 subjects with Non Proliferative Diabetic Retinopathy(mild, moderate and severe). 15 subjects with Proliferative Diabetic Retinopathy Healthy Controls 15 age matched control subjects

Association of VAgus Nerve Stimulation and Treadmill Training for GAit Rehabilitation in DE Novo Parkinson's DiseaseNA

NOT_YET_RECRUITING·NCT07337226 · Fondazione Policlinico Universitario Campus Bio-Medico

60 enrolled · 2026-01 · → 2027-10

The goal of this clinical trial is to learn if transcutaneous auricular vagus nerve stimulation (taVNS) can improve gait and brain function in people with diagnosis of idiopathic Parkinson's disease (

Idiopathic Parkinson's Disease (PD)

Transcutaneous Auricular Vagus Nerve Stimulation (taVNS) Sham Transcutaneous Auricular Vagus Nerve Stimulation (Sham taVNS) Conventional Physical Therapy (cPT)

The NO-ALS Study: A Trial of Nicotinamide/Pterostilbene Supplement in ALS.NA

ACTIVE_NOT_RECRUITING·NCT04562831 · Haukeland University Hospital

380 enrolled · 2020-10-07 · → 2026-10-31

Amyotrophic lateral sclerosis (ALS) is a serious rapidly progressive disease of the nervous system. The average survival from the time of diagnosis is 3 years. Apart from Riluzole, there is no effecti

Amyotrophic Lateral Sclerosis

EH301 (Nicotinamide Riboside/Pterostilbene)

Ferrochelating Treatment in Patients Affected by Neurodegeneration With Brain Iron Accumulation (NBIA)PHASE2

UNKNOWN·NCT00907283 · Ente Ospedaliero Ospedali Galliera

20 enrolled · 2008-11 · → 2024-12

This trial is a multicenter, unblinded, single-arm pilot study, lasting one year (plus one year extension Amendment n.3 25 August 2009, plus two years follow-up Amendment n.7) , to evaluate the effica

Neurodegenerative Disease Iron Overload

Deferiprone

Effect of the Vojta Therapy in Patients Multiple SclerosisNA

UNKNOWN·NCT05558683 · Aymara Abreu Corrales

25 enrolled · 2022-12-01 · → 2023-06-01

Multiple sclerosis is the most common disabling neurological disease in young adults. Inflammation, demyelination, neurodegeneration, gliosis and repair processes are involved in its process, which ar

Multiple Sclerosis

Randomized clinical trial.

The Effect of RNS60 on ALS BiomarkersPHASE2

COMPLETED·NCT03456882 · Mario Negri Institute for Pharmacological Research

147 enrolled · 2017-05-30 · → 2020-11-23

Amyotrophic Lateral Sclerosis (ALS) is a rare lethal neurodegenerative disease involving inflammation. Riluzole, the only drug for ALS, improves median survival by 3 months. This prompts new treatment

Amyotrophic Lateral Sclerosis

RNS60

No curated ClinVar variants loaded for this hypothesis.

Run scripts/backfill_clinvar_variants.py to fetch P/LP/VUS variants.

🔍 Search ClinVar for SMPD3 →

No DepMap CRISPR Chronos data found for SMPD3.

Run python3 scripts/backfill_hypothesis_depmap.py to populate.

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📖 References (11)

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Wedekind Silke. MMW Fortschritte der Medizin (2016)
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Using dynamic monitoring of choices to predict and understand risk preferences.
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The COVID-19 Vaccination Still Matters: Omicron Variant Is a Final Wake-Up Call for the Rich to Help the Poor.
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Parkinson risk in idiopathic REM sleep behavior disorder: preparing for neuroprotective trials.
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Common uropathogens among diabetic patients with urinary tract infection at Jinja Regional Referral Hospital, Uganda.
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PubMed↗DOI↗

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h-var-e81fbd3868 SMPD3 Neutral sphingomyelinase-2 / synaptic ceramide signaling

▸Metadata

source_id	h-var-e81fbd3868
source_table	hypotheses
_schema_version	1

📊 Evidence Profile

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Evidence		72%
Novelty		78%
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Druggability		65%
Safety		55%
Competition		82%
Data avail.		70%
Reproducibility		68%

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Neutral Sphingomyelinase-2 Inhibition for Synaptic Protection in Neurodegeneration

🧪 Overview

Mechanistic Overview

Mechanistic Overview

Molecular and Cellular Rationale

Evidence Supporting the Hypothesis

Contradictory Evidence, Caveats, and Failure Modes

Clinical and Translational Relevance

Experimental Predictions and Validation Strategy

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🧬 3D Protein Structure — SMPD3

💉 Clinical Trials (13)Relevance: 2%

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📗 Cite This Artifact

Neutral Sphingomyelinase-2 Inhibition for Synaptic Protection in Neurodegeneration

🧪 Overview

Mechanistic Overview

Mechanistic Overview

Molecular and Cellular Rationale

Evidence Supporting the Hypothesis

Contradictory Evidence, Caveats, and Failure Modes

Clinical and Translational Relevance

Experimental Predictions and Validation Strategy

Decision-Oriented Summary

🧬 Mechanism

⚖️ Evidence

🏥 Translation

🧬 3D Protein Structure — SMPD3

💉 Clinical Trials (13)Relevance: 2%

🏆 Tournament

🏆 Arenas / Elo

📊 Market Indicators

💾 Resource Usage

🧭 Related

activates (14)

alters (1)

associated with (2)

biomarker for (1)

catalyzes (1)

causes (13)

co localizes in (1)

disrupts (1)

inhibits (2)

modulates (2)

promotes (1)

protective against (2)

regulates (7)

risk factor for (1)

therapeutic target for (1)

📖 References (11)

supports (2)

🧬 Related Hypotheses — same target / disease (20)

💬 Discussion