Thermoneutral housing worsens MASLD and reveals defective brown adipose tissue response to β3-adrenergic stimulation.

Metabolic dysfunction-associated steatotic liver disease (MASLD), and its more advanced stage metabolic dysfunction-associated steatohepatitis, is the most common chronic liver disease, constituting a major public health issue. Relevant preclinical models are needed to define molecular mechanisms underlying MASLD pathogenesis and evaluate therapeutic approaches. The majority of the lipids accumulating in the liver upon MASLD originate from adipose tissue and appropriate models to study the liver-adipose tissue dialog are also needed.

Neuraminidase 1 secondary deficiency contributes to CNS pathology in neurological mucopolysaccharidoses via brain protein hypersialylation.

Mucopolysaccharidoses (MPS) are lysosomal storage diseases caused by defects in catabolism of glycosaminoglycans. MPS I, II, III, and VII, which are associated with lysosomal accumulation of heparan sulphate (HS), manifest with neurological deterioration and currently lack effective treatments. We report that neuraminidase 1 (NEU1) activity is drastically reduced in brain tissues of patients with neurological MPS and mouse models but not in neurological lysosomal disorders without HS storage.

Advanced strategies for detecting acid sphingomyelinase deficiency type B with attenuated phenotypes.

Background: Acid Sphingomyelinase Deficiency (ASMD) type B is a rare lysosomal disorder caused by SMPD1 mutations. Due to its low prevalence and clinical heterogeneity, diagnosis is challenging, and detection is crucial for the initiation of enzyme replacement therapy.

Methods: We conducted a retrospective study (RnIPH 2024-85) at Toulouse University Hospital, analyzing 359,802 lipid profiles (2012-2023).

Liver gene expression and its rewiring in hepatic steatosis are controlled by PI3Kα-dependent hepatocyte signaling.

Insulin and other growth factors are key regulators of liver gene expression, including in metabolic diseases. Most of the phosphoinositide 3-kinase (PI3K) activity induced by insulin is considered to be dependent on PI3Kα. We used mice lacking p110α, the catalytic subunit of PI3Kα, to investigate its role in the regulation of liver gene expression in health and in metabolic dysfunction-associated steatotic liver disease (MASLD).

Acid sphingomyelinase deficiency: Laboratory diagnosis, genetic and epidemiologic aspects of a 50-year French cohort.

Objectives: Laboratory diagnosis of acid sphingomyelinase (ASM) deficiency (ASMD) was implemented in France in the early 1970s. The aims of this study were (i) to review the combined use of successively developed strategies - enzyme measurement, genetic testing, and biomarkers analysis - and (ii) to describe the mutational spectrum and epidemiological characteristics of a large patient cohort followed in French hospitals.

Results: During the 1974-2023 period, 271 patients with ASMD (238 families) were diagnosed.

Acid Ceramidase Deficiency: New Insights on SMA-PME Natural History, Biomarkers, and Enzyme Activity Assay.

Background And Objectives: Spinal muscular atrophy with progressive myoclonic epilepsy (SMA-PME) due to acid ceramidase deficiency is a rare disorder, allelic with Farber disease, resulting from recessive variants. Patients present in early childhood with muscle weakness due to anterior horn degeneration and/or progressive drug-resistant myoclonic epilepsy. Death usually results from respiratory complications or status epilepticus during adolescence.

Cerebrotendinous xanthomatosis: a literature review and case study.

Cerebrotendinous xanthomatosis (CTX) is a rare but treatable inherited neurometabolic disorder that can lead to severe sequelae if left untreated. Chenodeoxycholic acid is a safe and effective treatment for CTX. Early diagnosis is essential to improve patient outcomes.

Ceramide metabolism alterations contribute to Tumor Necrosis Factor-induced melanoma dedifferentiation and predict resistance to immune checkpoint inhibitors in advanced melanoma patients.

Introduction: Advanced cutaneous melanoma is a skin cancer characterized by a poor prognosis and high metastatic potential. During metastatic spread, melanoma cells often undergo dedifferentiation toward an invasive phenotype, resulting in reduced expression of microphthalmia-associated transcription factor (MITF)-dependent melanoma antigens and facilitating immune escape. Tumor Necrosis Factor (TNF) is known to be a key factor in melanoma dedifferentiation.

Secondary deficiency of neuraminidase 1 contributes to CNS pathology in neurological mucopolysaccharidoses via hypersialylation of brain glycoproteins.

Mucopolysaccharidoses (MPS) are lysosomal storage diseases caused by defects in catabolism of glycosaminoglycans. MPS I, II, III and VII are associated with lysosomal accumulation of heparan sulphate and manifest with neurological deterioration. Most of these neurological MPS currently lack effective treatments.

Human genetic defects of sphingolipid synthesis.

Sphingolipids are ubiquitous lipids, present in the membranes of all cell types, the stratum corneum and the circulating lipoproteins. Autosomal recessive as well as dominant diseases due to disturbed sphingolipid biosynthesis have been identified, including defects in the synthesis of ceramides, sphingomyelins and glycosphingolipids. In many instances, these gene variants result in the loss of catalytic function of the mutated enzymes.

Adiponectin overexpression improves metabolic abnormalities caused by acid ceramidase deficiency but does not prolong lifespan in a mouse model of Farber Disease.

Farber Disease is a debilitating and lethal childhood disease of ceramide accumulation caused by acid ceramidase deficiency. The potent induction of a ligand-gated neutral ceramidase activity promoted by adiponectin may provide sufficient lowering of ceramides to allow for the treatment of Farber Disease. In vitro, adiponectin or adiponectin receptor agonist treatments lowered total ceramide concentrations in human fibroblasts from a patient with Farber Disease.

Multivalent pyrrolidines acting as pharmacological chaperones against Gaucher disease.

A concise asymmetric synthesis of clickable enantiomeric pyrrolidines was achieved using Crabbé-Ma allenation. The synthesized iminosugars were grafted by copper-free strain-promoted alkyne-azide cycloaddition onto phosphorus dendrimers. The hexavalent and dodecavalent pyrrolidines were evaluated as β-glucocerebrosidase inhibitors.

Sphingolipid paracrine signaling impairs keratinocyte adhesion to promote melanoma invasion.

Melanoma is the deadliest form of skin cancer due to its propensity to metastasize. It arises from melanocytes, which are attached to keratinocytes within the basal epidermis. Here, we hypothesize that, in addition to melanocyte-intrinsic modifications, dysregulation of keratinocyte functions could initiate early-stage melanoma cell invasion.

Effects of miglustat therapy on neurological disorder and survival in early-infantile Niemann-Pick disease type C: a national French retrospective study.

Background: Niemann-Pick disease type C (NP-C) is a rare neurovisceral lysosomal lipid storage disease characterized by progressive neurodegeneration and premature death. While miglustat can stabilize neurological manifestations in later onset forms of NP-C, its efficacy in the early-infantile neurological form has not been demonstrated. In this observational retrospective study, we compared long-term neurodevelopmental outcome and survival between an untreated and a treated group of early infantile NP-C patients.

Natural history of GM1 gangliosidosis-Retrospective cohort study of 61 French patients from 1998 to 2019.

GM1 gangliosidosis is a rare lysosomal storage disorder associated with β-galactosidase enzyme deficiency. There are three types of GM1 gangliosidosis based on age of symptom onset, which correlate with disease severity. In 2019, we performed a retrospective multicentric study including all patients diagnosed with GM1 gangliosidosis in France since 1998.

Phosphorus Dendrimers for Metal-Free Ligation: Design of Multivalent Pharmacological Chaperones against Gaucher Disease.

The first phosphorus dendrimers built on a cyclotriphosphazene core and decorated with six or twelve monofluorocyclooctyne units were prepared. A simple stirring allowed the grafting of N-hexyl deoxynojirimycin inhitopes onto their surface by copper-free strain promoted alkyne-azide cycloaddition click reaction. The synthesized iminosugars clusters were tested as multivalent inhibitors of the biologically relevant enzymes β-glucocerebrosidase and acid α-glucosidase, involved in Gaucher and Pompe lysosomal storage diseases, respectively.

Unusual circumstance for craniopharyngioma discovery on meningoencephalitis: a pediatric case report.

Background: Craniopharyngioma is a rare condition in children, but it is the most frequent tumor that occurs in the hypothalamic pituitary region. Chemical meningitis has been described as an uncommon postoperative complication, but no chemical meningitis due to a spontaneous rupture leading to craniopharyngioma diagnosis in children has been reported.

Case Presentation: This is a case of a 13-year-old boy presenting with fever, vomiting and headache for two days.

Acid Ceramidase Deficiency: Bridging Gaps between Clinical Presentation, Mouse Models, and Future Therapeutic Interventions.

Farber disease (FD) and spinal muscular atrophy with progressive myoclonic epilepsy (SMA-PME) are ultra-rare, autosomal-recessive, acid ceramidase (ACDase) deficiency disorders caused by gene mutations. Currently, 73 different mutations in the gene have been described in humans. These mutations lead to reduced ACDase activity and ceramide (Cer) accumulation in many tissues.

Gene Editing Corrects a G > A Transition from a GM1 Gangliosidosis Patient.

Ganglioside-monosialic acid (GM1) gangliosidosis, a rare autosomal recessive disorder, is frequently caused by deleterious single nucleotide variants (SNVs) in gene. These variants result in reduced β-galactosidase (β-gal) activity, leading to neurodegeneration associated with premature death. Currently, no effective therapy for GM1 gangliosidosis is available.

The clinical spectrum of SMA-PME and in vitro normalization of its cellular ceramide profile.

Objective: The objectives of this study were to define the clinical and biochemical spectrum of spinal muscular atrophy with progressive myoclonic epilepsy (SMA-PME) and to determine if aberrant cellular ceramide accumulation could be normalized by enzyme replacement.

Methods: Clinical features of 6 patients with SMA-PME were assessed by retrospective chart review, and a literature review of 24 previously published cases was performed. Leukocyte enzyme activity of acid ceramidase was assessed with a fluorescence-based assay.