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1.
Glycobiology ; 34(6)2024 Apr 24.
Artículo en Inglés | MEDLINE | ID: mdl-38690785

RESUMEN

Cellulose is an abundant component of plant cell wall matrices, and this para-crystalline polysaccharide is synthesized at the plasma membrane by motile Cellulose Synthase Complexes (CSCs). However, the factors that control CSC activity and motility are not fully resolved. In a targeted chemical screen, we identified the alkylated nojirimycin analog N-Dodecyl Deoxynojirimycin (ND-DNJ) as a small molecule that severely impacts Arabidopsis seedling growth. Previous work suggests that ND-DNJ-related compounds inhibit the biosynthesis of glucosylceramides (GlcCers), a class of glycosphingolipid associated with plant membranes. Our work uncovered major changes in the sphingolipidome of plants treated with ND-DNJ, including reductions in GlcCer abundance and altered acyl chain length distributions. Crystalline cellulose content was also reduced in ND-DNJ-treated plants as well as plants treated with the known GlcCer biosynthesis inhibitor N-[2-hydroxy-1-(4-morpholinylmethyl)-2-phenyl ethyl]-decanamide (PDMP) or plants containing a genetic disruption in GLUCOSYLCERAMIDE SYNTHASE (GCS), the enzyme responsible for sphingolipid glucosylation that results in GlcCer synthesis. Live-cell imaging revealed that CSC speed distributions were reduced upon treatment with ND-DNJ or PDMP, further suggesting an important relationship between glycosylated sphingolipid composition and CSC motility across the plasma membrane. These results indicate that multiple interventions compromising GlcCer biosynthesis disrupt cellulose deposition and CSC motility, suggesting that GlcCers regulate cellulose biosynthesis in plants.


Asunto(s)
Arabidopsis , Celulosa , Glucosilceramidas , Glucosiltransferasas , Arabidopsis/metabolismo , Glucosiltransferasas/metabolismo , Glucosiltransferasas/genética , Celulosa/metabolismo , Celulosa/biosíntesis , Glucosilceramidas/metabolismo , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , 1-Desoxinojirimicina/farmacología , 1-Desoxinojirimicina/análogos & derivados , Pared Celular/metabolismo
2.
Sci Signal ; 17(829): eadk8249, 2024 Mar 26.
Artículo en Inglés | MEDLINE | ID: mdl-38530880

RESUMEN

Mutations in the gene encoding the lysosomal enzyme glucocerebrosidase (GCase) are responsible for Gaucher disease (GD) and are considered the strongest genetic risk factor for Parkinson's disease (PD) and Lewy body dementia (LBD). GCase deficiency leads to extensive accumulation of glucosylceramides (GCs) in cells and contributes to the neuropathology of GD, PD, and LBD by triggering chronic neuroinflammation. Here, we investigated the mechanisms by which GC accumulation induces neuroinflammation. We found that GC accumulation within microglia induced by pharmacological inhibition of GCase triggered STING-dependent inflammation, which contributed to neuronal loss both in vitro and in vivo. GC accumulation in microglia induced mitochondrial DNA (mtDNA) leakage to the cytosol to trigger STING-dependent inflammation. Rapamycin, a compound that promotes lysosomal activity, improved mitochondrial function, thereby decreasing STING signaling. Furthermore, lysosomal damage caused by GC accumulation led to defects in the degradation of activated STING, further exacerbating inflammation mediated by microglia. Thus, limiting STING activity may be a strategy to suppress neuroinflammation caused by GCase deficiency.


Asunto(s)
Enfermedad de Gaucher , Enfermedad de Parkinson , Animales , Ratones , alfa-Sinucleína/metabolismo , Enfermedad de Gaucher/genética , Enfermedad de Gaucher/patología , Glucosilceramidas/metabolismo , Inflamación/metabolismo , Lisosomas/metabolismo , Microglía/metabolismo , Enfermedades Neuroinflamatorias , Enfermedad de Parkinson/metabolismo
3.
Aging Cell ; 23(4): e14077, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38303548

RESUMEN

Idiopathic Parkinson's disease (PD) is characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta, which is associated with neuroinflammation and reactive gliosis. The underlying cause of PD and the concurrent neuroinflammation are not well understood. In this study, we utilize human and murine neuronal lines, stem cell-derived dopaminergic neurons, and mice to demonstrate that three previously identified genetic risk factors for PD, namely SATB1, MIR22HG, and GBA, are components of a single gene regulatory pathway. Our findings indicate that dysregulation of this pathway leads to the upregulation of glucocerebrosides (GluCer), which triggers a cellular senescence-like phenotype in dopaminergic neurons. Specifically, we discovered that downregulation of the transcriptional repressor SATB1 results in the derepression of the microRNA miR-22-3p, leading to decreased GBA expression and subsequent accumulation of GluCer. Furthermore, our results demonstrate that an increase in GluCer alone is sufficient to impair lysosomal and mitochondrial function, thereby inducing cellular senescence. Dysregulation of the SATB1-MIR22-GBA pathway, observed in both PD patients and normal aging, leads to lysosomal and mitochondrial dysfunction due to the GluCer accumulation, ultimately resulting in a cellular senescence-like phenotype in dopaminergic neurons. Therefore, our study highlights a novel pathway involving three genetic risk factors for PD and provides a potential mechanism for the senescence-induced neuroinflammation and reactive gliosis observed in both PD and normal aging.


Asunto(s)
Proteínas de Unión a la Región de Fijación a la Matriz , MicroARNs , Enfermedad de Parkinson , Humanos , Ratones , Animales , Neuronas Dopaminérgicas/metabolismo , Proteínas de Unión a la Región de Fijación a la Matriz/genética , Proteínas de Unión a la Región de Fijación a la Matriz/metabolismo , Glucosilceramidas/metabolismo , Gliosis , Enfermedades Neuroinflamatorias , Enfermedad de Parkinson/genética , Enfermedad de Parkinson/metabolismo , MicroARNs/genética , MicroARNs/metabolismo , Senescencia Celular/genética , Factores de Transcripción/metabolismo , Fenotipo
4.
J Lipid Res ; 65(3): 100508, 2024 03.
Artículo en Inglés | MEDLINE | ID: mdl-38280458

RESUMEN

Lipid transport is an essential cellular process with importance to human health, disease development, and therapeutic strategies. Type IV P-type ATPases (P4-ATPases) have been identified as membrane lipid flippases by utilizing nitrobenzoxadiazole (NBD)-labeled lipids as substrates. Among the 14 human type IV P-type ATPases, ATP10D was shown to flip NBD-glucosylceramide (GlcCer) across the plasma membrane. Here, we found that conversion of incorporated GlcCer (d18:1/12:0) to other sphingolipids is accelerated in cells exogenously expressing ATP10D but not its ATPase-deficient mutant. These findings suggest that 1) ATP10D flips unmodified GlcCer as well as NBD-GlcCer at the plasma membrane and 2) ATP10D can translocate extracellular GlcCer, which is subsequently converted to other metabolites. Notably, exogenous expression of ATP10D led to the reduction in cellular hexosylceramide levels. Moreover, the expression of GlcCer flippases, including ATP10D, also reduced cellular hexosylceramide levels in fibroblasts derived from patients with Gaucher disease, which is a lysosomal storage disorder with excess GlcCer accumulation. Our study highlights the contribution of ATP10D to the regulation of cellular GlcCer levels and maintaining lipid homeostasis.


Asunto(s)
Glucosilceramidas , ATPasas Tipo P , Humanos , Glucosilceramidas/metabolismo , Transporte Biológico , Membrana Celular/metabolismo , Adenosina Trifosfatasas/metabolismo , Homeostasis , ATPasas Tipo P/metabolismo
5.
Cell Struct Funct ; 49(1): 1-10, 2024 Jan 23.
Artículo en Inglés | MEDLINE | ID: mdl-38072450

RESUMEN

Gaucher disease (GD) is a recessively inherited lysosomal storage disorder characterized by a deficiency of lysosomal glucocerebrosidase (GBA1). This deficiency results in the accumulation of its substrate, glucosylceramide (GlcCer), within lysosomes. Here, we investigated lysosomal abnormalities in fibroblasts derived from patients with GD. It is noteworthy that the cellular distribution of lysosomes and lysosomal proteolytic activity remained largely unaffected in GD fibroblasts. However, we found that lysosomal membranes of GD fibroblasts were susceptible to damage when exposed to a lysosomotropic agent. Moreover, the susceptibility of lysosomal membranes to a lysosomotropic agent could be partly restored by exogenous expression of wild-type GBA1. Here, we report that the lysosomal membrane integrity is altered in GD fibroblasts, but lysosomal distribution and proteolytic activity is not significantly altered.Key words: glucosylceramide, lysosome, Gaucher disease, lysosomotropic agent.


Asunto(s)
Enfermedad de Gaucher , Humanos , Enfermedad de Gaucher/metabolismo , Glucosilceramidas/metabolismo , Fibroblastos/metabolismo , Lisosomas/metabolismo , Membranas Intracelulares/metabolismo
6.
Sci Rep ; 13(1): 22537, 2023 12 18.
Artículo en Inglés | MEDLINE | ID: mdl-38110468

RESUMEN

Glucosylceramide (GlcCer) belongs to sphingolipids and is found naturally in plant foods and other sources that humans consume daily. Our previous studies demonstrated that GlcCer prevents inflammatory bowel disease both in vitro and in vivo, whose patients are increasing alarmingly. Although some lipids are vulnerable to oxidation which changes their structure and activities, it is unknown whether oxidative modification of GlcCer affects its activity. In this research, we oxidized GlcCer in the presence of a photosensitizer, analyzed the oxide by mass spectrometric techniques, and examined its anti-inflammatory activity in lipopolysaccharide (LPS)-treated differentiated Caco-2 cells as in vitro model of intestinal inflammation. The results showed that GlcCer is indeed oxidized, producing GlcCer hydroperoxide (GlcCerOOH) as a primary oxidation product. We also found that oxidized GlcCer preserves beneficial functions of GlcCer, suppressing inflammatory-related gene expressions. These findings suggested that GlcCerOOH may perform as an LPS recognition antagonist to discourage inflammation rather than induce inflammation.


Asunto(s)
Glucosilceramidas , Lipopolisacáridos , Humanos , Lipopolisacáridos/toxicidad , Glucosilceramidas/metabolismo , Células CACO-2 , Inflamación/inducido químicamente , Inflamación/genética , Expresión Génica
7.
Dis Model Mech ; 16(10)2023 10 01.
Artículo en Inglés | MEDLINE | ID: mdl-37815467

RESUMEN

The lipid storage disease Niemann Pick type C (NPC) causes neurodegeneration owing primarily to loss of NPC1. Here, we employed a Drosophila model to test links between glycosphingolipids, neurotransmission and neurodegeneration. We found that Npc1a nulls had elevated neurotransmission at the glutamatergic neuromuscular junction (NMJ), which was phenocopied in brainiac (brn) mutants, impairing mannosyl glucosylceramide (MacCer) glycosylation. Npc1a; brn double mutants had the same elevated synaptic transmission, suggesting that Npc1a and brn function within the same pathway. Glucosylceramide (GlcCer) synthase inhibition with miglustat prevented elevated neurotransmission in Npc1a and brn mutants, further suggesting epistasis. Synaptic MacCer did not accumulate in the NPC model, but GlcCer levels were increased, suggesting that GlcCer is responsible for the elevated synaptic transmission. Null Npc1a mutants had heightened neurodegeneration, but no significant motor neuron or glial cell death, indicating that dying cells are interneurons and that elevated neurotransmission precedes neurodegeneration. Glycosphingolipid synthesis mutants also had greatly heightened neurodegeneration, with similar neurodegeneration in Npc1a; brn double mutants, again suggesting that Npc1a and brn function in the same pathway. These findings indicate causal links between glycosphingolipid-dependent neurotransmission and neurodegeneration in this NPC disease model.


Asunto(s)
Drosophila , Glicoesfingolípidos , Enfermedades Neurodegenerativas , Enfermedad de Niemann-Pick Tipo C , Animales , Glucosilceramidas/metabolismo , Glicoesfingolípidos/metabolismo , Enfermedad de Niemann-Pick Tipo C/metabolismo , Transmisión Sináptica , Modelos Animales de Enfermedad , Enfermedades Neurodegenerativas/metabolismo
8.
J Biol Chem ; 299(9): 105162, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37586586

RESUMEN

Sphingomyelin synthase (SMS)-related protein (SMSr) is a phosphatidylethanolamine phospholipase C (PE-PLC) that is conserved and ubiquitous in mammals. However, its biological function is still not clear. We previously observed that SMS1 deficiency-mediated glucosylceramide accumulation caused nonalcoholic fatty liver diseases (NAFLD), including nonalcoholic steatohepatitis (NASH) and liver fibrosis. Here, first, we evaluated high-fat diet/fructose-induced NAFLD in Smsr KO and WT mice. Second, we evaluated whether SMSr deficiency can reverse SMS1 deficiency-mediated NAFLD, using Sms1/Sms2 double and Sms1/Sms2/Smsr triple KO mice. We found that SMSr/PE-PLC deficiency attenuated high-fat diet/fructose-induced fatty liver and NASH, and attenuated glucosylceramide accumulation-induced NASH, fibrosis, and tumor formation. Further, we found that SMSr/PE-PLC deficiency reduced the expression of many inflammatory cytokines and fibrosis-related factors, and PE supplementation in vitro or in vivo mimicked the condition of SMSr/PE-PLC deficiency. Furthermore, we demonstrated that SMSr/PE-PLC deficiency or PE supplementation effectively prevented membrane-bound ß-catenin transfer to the nucleus, thereby preventing tumor-related gene expression. Finally, we observed that patients with NASH had higher SMSr protein levels in the liver, lower plasma PE levels, and lower plasma PE/phosphatidylcholine ratios, and that human plasma PE levels are negatively associated with tumor necrosis factor-α and transforming growth factor ß1 levels. In conclusion, SMSr/PE-PLC deficiency causes PE accumulation, which can attenuate fatty liver, NASH, and fibrosis. These results suggest that SMSr/PE-PLC inhibition therapy may mitigate NAFLD.


Asunto(s)
Neoplasias , Enfermedad del Hígado Graso no Alcohólico , Transferasas (Grupos de Otros Fosfatos Sustitutos) , Animales , Humanos , Ratones , Fructosa/efectos adversos , Glucosilceramidas/metabolismo , Hígado/metabolismo , Cirrosis Hepática/patología , Neoplasias/genética , Neoplasias/metabolismo , Enfermedad del Hígado Graso no Alcohólico/genética , Enfermedad del Hígado Graso no Alcohólico/metabolismo , Fosfatidiletanolaminas/sangre , Transferasas (Grupos de Otros Fosfatos Sustitutos)/genética , Transferasas (Grupos de Otros Fosfatos Sustitutos)/metabolismo , Ratones Noqueados , Masculino , Femenino , Dieta Alta en Grasa/efectos adversos
10.
J Lipid Res ; 64(7): 100394, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-37245562

RESUMEN

The addition of excess glucose to the diet drives a coordinated response of lipid metabolism pathways to tune the membrane composition to the altered diet. Here, we have employed targeted lipidomic approaches to quantify the specific changes in the phospholipid and sphingolipid populations that occur in elevated glucose conditions. The lipids within wild-type Caenorhabditis elegans are strikingly stable with no significant changes identified in our global mass spectrometry-based analysis. Previous work has identified ELO-5, an elongase that is critical for the synthesis of monomethyl branched-chain fatty acids (mmBCFAs), as essential for surviving elevated glucose conditions. Therefore, we performed targeted lipidomics on elo-5 RNAi-fed animals and identified several significant changes in these animals in lipid species that contain mmBCFAs as well as in species that do not contain mmBCFAs. Of particular note, we identified a specific glucosylceramide (GlcCer 17:1;O2/22:0;O) that is also significantly upregulated with glucose in wild-type animals. Furthermore, compromising the production of the glucosylceramide pool with elo-3 or cgt-3 RNAi leads to premature death in glucose-fed animals. Taken together, our lipid analysis has expanded the mechanistic understanding of metabolic rewiring with glucose feeding and has identified a new role for the GlcCer 17:1;O2/22:0;O.


Asunto(s)
Proteínas de Caenorhabditis elegans , Glucosilceramidas , Animales , Glucosilceramidas/metabolismo , Lipidómica , Glucosa/metabolismo , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo
11.
J Invest Dermatol ; 143(10): 1964-1972.e4, 2023 10.
Artículo en Inglés | MEDLINE | ID: mdl-37004877

RESUMEN

Ligand activation of the aryl hydrocarbon receptor (AHR) accelerates keratinocyte differentiation and the formation of the epidermal permeability barrier. Several classes of lipids, including ceramides, are critical to the epidermal permeability barrier. In normal human epidermal keratinocytes, the AHR ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin, increased RNA levels of ceramide metabolism and transport genes: uridine diphosphate glucose ceramide glucosyltransferase (UGCG), ABCA12, GBA1, and SMPD1. Levels of abundant skin ceramides were also increased by 2,3,7,8-tetrachlorodibenzo-p-dioxin. These included the metabolites synthesized by UGCG, glucosylceramides, and acyl glucosylceramides. Chromatin immunoprecipitation-sequence analysis and luciferase reporter assays identified UGCG as a direct AHR target. The AHR antagonist, GNF351, inhibited the 2,3,7,8-tetrachlorodibenzo-p-dioxin-mediated RNA and transcriptional increases. Tapinarof, an AHR ligand approved for the treatment of psoriasis, increased UGCG RNA, protein, and its lipid metabolites hexosylceramides as well as increased the RNA expression of ABCA12, GBA1, and SMPD1. In Ahr-null mice, Ugcg RNA and hexosylceramides were lower than those in the wild type. These results indicate that the AHR regulates the expression of UGCG, a ceramide-metabolizing enzyme required for ceramide trafficking, keratinocyte differentiation, and epidermal permeability barrier formation.


Asunto(s)
Glucosilceramidas , Dibenzodioxinas Policloradas , Animales , Ratones , Humanos , Glucosilceramidas/metabolismo , Uridina Difosfato Glucosa , Receptores de Hidrocarburo de Aril/genética , Receptores de Hidrocarburo de Aril/metabolismo , Ligandos , ARN
12.
Biomolecules ; 13(3)2023 02 24.
Artículo en Inglés | MEDLINE | ID: mdl-36979371

RESUMEN

Chitotriosidase is an enzyme produced and secreted in large amounts by activated macrophages, especially macrophages loaded with phagocytozed glycosphingolipid in Gaucher disease. Macrophages phagocytose decayed blood cells that contain a lot of sphingolipid-rich cell membranes. In Gaucher disease, due to a deficit in beta-glucocerebrosidase activity, the phagocytozed substrate glucocerebroside cannot undergo further catabolism. In such a situation, macrophages secrete chitotriosidase in proportion to the degree of overload. Gaucher disease (GD) is a recessively inherited disorder resulting in storage of glucosylceramide (GlcCer) in lysosomes of tissue macrophages. It is directly caused by the deficiency of beta-glucocerebrosidase (GBA) activity. Chitotriosidase has been measured systematically each year in the same group of 49 patients with type 1 and 3 GD for over 20 years. Our analysis showed that chitotriosidase is very sensitive biomarker to enzyme replacement therapy (ERT). The response to treatment introduction is of an almost immediate nature, lowering pathologically high chitotriosidase levels by a factor of 2 in a time scale of 8 months, on average. Long term enzyme replacement therapy (ERT) brings chitotriosidase activity close to reference values. Finally, reducing the dose of ERT quickly boosts chitotriosidase activity, but restoring the initial dose of treatment brings chitotriosidase level of activity back onto the decreasing time trajectory.


Asunto(s)
Enfermedad de Gaucher , Humanos , Enfermedad de Gaucher/tratamiento farmacológico , Enfermedad de Gaucher/metabolismo , Glucosilceramidasa , Estudios Longitudinales , Hexosaminidasas/metabolismo , Hexosaminidasas/uso terapéutico , Glucosilceramidas/metabolismo , Glucosilceramidas/uso terapéutico
13.
PLoS Pathog ; 19(3): e1011232, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36920967

RESUMEN

Due to climate changes, there has been a large expansion of emerging tick-borne zoonotic viruses, including Heartland bandavirus (HRTV) and Dabie bandavirus (DBV). As etiologic agents of hemorrhagic fever with high fatality, HRTV and DBV have been recognized as dangerous viral pathogens that likely cause future wide epidemics. Despite serious health concerns, the mechanisms underlying viral infection are largely unknown. HRTV and DBV Gn and Gc are viral surface glycoproteins required for early entry events during infection. Glycosphingolipids, including galactosylceramide (GalCer), glucosylceramide (GlcCer) and lactosylceramide (LacCer), are a class of membrane lipids that play essential roles in membrane structure and viral lifecycle. Here, our genome-wide CRISPR/Cas9 knockout screen identifies that glycosphingolipid biosynthesis pathway is essential for HRTV and DBV infection. The deficiency of UDP-glucose ceramide glucosyltransferase (UGCG) that produces GlcCer resulted in the loss of infectivity of recombinant viruses pseudotyped with HRTV or DBV Gn/Gc glycoproteins. Conversely, exogenous supplement of GlcCer, but not GalCer or LacCer, recovered viral entry of UGCG-deficient cells in a dose-dependent manner. Biophysical analyses showed that GlcCer targeted the lipid-head-group binding pocket of Gc to form a stable protein-lipid complex, which allowed the insertion of Gc protein into host lysosomal membrane lipid bilayers for viral fusion. Mutagenesis showed that D841 residue at the Gc lipid binding pocket was critical for GlcCer interaction and thereby, viral entry. These findings reveal detailed mechanism of GlcCer glycosphingolipid in HRTV and DBV Gc-mediated membrane fusion and provide a potential therapeutic target for tickborne virus infection.


Asunto(s)
Glucosilceramidas , Virus ARN , Glucosilceramidas/metabolismo , Fusión de Membrana , Glicoproteínas/química , Lactosilceramidos , Virus ARN/metabolismo
14.
Immunity ; 56(2): 307-319.e8, 2023 02 14.
Artículo en Inglés | MEDLINE | ID: mdl-36736320

RESUMEN

Gaucher disease (GD) is the most common lysosomal storage disease caused by recessive mutations in the degrading enzyme of ß-glucosylceramide (ß-GlcCer). However, it remains unclear how ß-GlcCer causes severe neuronopathic symptoms, which are not fully treated by current therapies. We herein found that ß-GlcCer accumulating in GD activated microglia through macrophage-inducible C-type lectin (Mincle) to induce phagocytosis of living neurons, which exacerbated Gaucher symptoms. This process was augmented by tumor necrosis factor (TNF) secreted from activated microglia that sensitized neurons for phagocytosis. This characteristic pathology was also observed in human neuronopathic GD. Blockade of these pathways in mice with a combination of FDA-approved drugs, minocycline (microglia activation inhibitor) and etanercept (TNF blocker), effectively protected neurons and ameliorated neuronopathic symptoms. In this study, we propose that limiting unrestrained microglia activation using drug repurposing provides a quickly applicable therapeutic option for fatal neuronopathic GD.


Asunto(s)
Enfermedad de Gaucher , Ratones , Animales , Humanos , Enfermedad de Gaucher/tratamiento farmacológico , Enfermedad de Gaucher/genética , Enfermedad de Gaucher/patología , Glucosilceramidasa/genética , Glucosilceramidasa/metabolismo , Glucosilceramidasa/uso terapéutico , Glucosilceramidas/metabolismo , Glucosilceramidas/uso terapéutico , Microglía/metabolismo , Neuronas/metabolismo , Fagocitosis
15.
Mol Genet Metab ; 138(3): 107527, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36739645

RESUMEN

In Gaucher disease type 1 (GD1), accumulation of the lipid substrates glucosylceramide and glucosylsphingosine (lyso-GL-1 or lyso-Gb1), primarily in the spleen, liver, and bone marrow, leads to progressive hepatosplenomegaly, anemia, thrombocytopenia, and skeletal disease. Plasma glucosylceramide elevations are modest, variable, and normalize within weeks of starting treatment before clinical changes are evident, and therefore, have limited value for monitoring treatment responses. Serum chitotriosidase activity, a widely used GD biomarker, is also elevated in many other conditions but is not measurable in 5-10% of individuals due to a common CHIT1 null variant. Plasma glucosylsphingosine is increasingly recognized as a useful biomarker for GD1: elevations are highly specific to the disease and show no overlap with normal controls, it is in the causal pathway of disease, and levels are reliably measured by liquid chromatography-tandem mass spectrometry. We report correlations of plasma glucosylsphingosine with baseline disease burden and eliglustat treatment response in previously untreated adults with GD1 in the Phase 2 (NCT00358150), open-label, single-arm trial of 26 patients with up to 8 years of follow-up and the placebo-controlled Phase 3 ENGAGE trial (NCT00891202) of 40 patients with up to 4.5 years of follow-up. At baseline, untreated patients showed moderate to strong correlations between plasma glucosylsphingosine and spleen volume, liver volume, and hemoglobin level. Organ volumes and hematologic parameters improved in parallel with reductions in plasma glucosylsphingosine during eliglustat treatment in both trials. Moderate correlations were seen between plasma glucosylsphingosine reduction and spleen and liver volume reductions during eliglustat treatment. These clinical trial data add to the growing body of evidence supporting plasma glucosylsphingosine as both a diagnostic and pharmacodynamic/response biomarker for GD1.


Asunto(s)
Enfermedad de Gaucher , Humanos , Adulto , Enfermedad de Gaucher/diagnóstico , Glucosilceramidas/metabolismo , Biomarcadores
16.
Stem Cell Res ; 64: 102919, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-36130446

RESUMEN

The GBA gene encodes the lysosomal enzyme glucocerebrosidase (GCase), responsible for the hydrolysis of glucocerebroside to glucose and ceramide. Heterozygous GBA mutations have been associated with the development of Parkinson's disease (PD) and dementia with Lewy bodies (DLB). We generated two induced pluripotent stem cell (iPSC) lines from PD patients carrying heterozygous GBA W378G or N370S mutations and subsequently produced isogenic control lines using CRISPR/Cas9 genome editing. The patient-derived iPSCs and isogenic control lines maintained full pluripotency, normal karyotypes, and differentiation capacity. All iPSC lines could be differentiated into dopaminergic neurons, thus providing valuable tools for studying PD pathogenesis.


Asunto(s)
Células Madre Pluripotentes Inducidas , Enfermedad de Parkinson , Humanos , Glucosa , Glucosilceramidasa/genética , Glucosilceramidasa/metabolismo , Glucosilceramidas/metabolismo , Células Madre Pluripotentes Inducidas/metabolismo , Mutación/genética , Enfermedad de Parkinson/patología
17.
FEBS Lett ; 596(18): 2400-2408, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35796054

RESUMEN

Glycosphingolipids (GSLs) fulfil diverse functions in cells. Abnormalities in their metabolism are associated with specific pathologies and, consequently, the pharmacological modulation of GSLs is considered a therapeutic avenue. The accurate measurement of in situ metabolism of GSLs and the modulatory impact of drugs is warranted. Employing synthesised sphingosine and sphinganine containing 13 C atoms, we developed a method to monitor the de novo synthesis of glucosylceramide, the precursor of complex GSLs, by the enzyme glucosylceramide synthase (GCS). We show that feeding cells with isotope-labelled precursor combined with liquid chromatography-mass spectrometry (MS)/MS analysis allows accurate determination of the IC50 values of therapeutically considered inhibitors (iminosugars and ceramide mimics) of GCS in cultured cells. Acquired data were comparable to those obtained with an earlier method using artificial fluorescently labelled ceramide to feed cells.


Asunto(s)
Glucosilceramidas , Esfingosina , Ceramidas/metabolismo , Glucosilceramidas/metabolismo , Glicoesfingolípidos/metabolismo , Espectrometría de Masas , Esfingosina/farmacología
18.
Sci Adv ; 8(28): eabn3326, 2022 07 15.
Artículo en Inglés | MEDLINE | ID: mdl-35857503

RESUMEN

Recessive variants in GBA1 cause Gaucher disease, a prevalent form of lysosome storage disease. GBA1 encodes a lysosomal enzyme that hydrolyzes glucosylceramide (GlcCer) into glucose and ceramide. Its loss causes lysosomal dysfunction and increased levels of GlcCer. We generated a null allele of the Drosophila ortholog Gba1b by inserting the Gal4 using CRISPR-Cas9. Here, we show that Gba1b is expressed in glia but not in neurons. Glial-specific knockdown recapitulates the defects found in Gba1b mutants, and these can be rescued by glial expression of human GBA1. We show that GlcCer is synthesized upon neuronal activity, and it is transported from neurons to glia through exosomes. Furthermore, we found that glial TGF-ß/BMP induces the transfer of GlcCer from neurons to glia and that the White protein, an ABCG transporter, promotes GlcCer trafficking to glial lysosomes for degradation.


Asunto(s)
Exosomas , Glucosilceramidas , Animales , Drosophila/metabolismo , Exosomas/metabolismo , Glucosilceramidasa/genética , Glucosilceramidasa/metabolismo , Glucosilceramidas/metabolismo , Humanos , Lisosomas/metabolismo , Neuroglía/metabolismo , Neuronas/metabolismo
19.
Virology ; 572: 17-27, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-35550476

RESUMEN

The enveloped positive-sense RNA viruses including Zika virus (ZIKV) need host lipids to successfully replicate. The nature of the lipids and the replication step(s) where lipids are utilized often vary amongst viruses. In this study, we demonstrate that ZIKV particle envelope is significantly enriched in distinct sphingolipid species. To determine the role of sphingolipids in ZIKV replication, we leveraged a panel of sphingolipid-deficient cell lines. Notably, knockout of glucosylceramide and lactosylceramide synthase encoding genes (GCSKO; B4G5KO) resulted in a marked decrease in ZIKV titers. GCSKO or pharmacological inhibition of GCS also led to a significant decrease in ZIKV genome replication. Further analysis indicated that GCSKO reduced intracellular virus titers but had minimal impact on ZIKV binding. Restoration of B4G5 expression in B4G5KO cells or supplementing PDMP-treated cells with glucosylceramide led to a significant rescue of ZIKV replication. Altogether, our findings suggest that ZIKV needs glycosphingolipids to facilitate virus replication.


Asunto(s)
Infección por el Virus Zika , Virus Zika , Glucosilceramidas/metabolismo , Glicoesfingolípidos/metabolismo , Humanos , Replicación Viral/fisiología , Virus Zika/fisiología
20.
Int J Mol Sci ; 23(9)2022 Apr 19.
Artículo en Inglés | MEDLINE | ID: mdl-35562868

RESUMEN

Hepatocellular carcinoma (HCC) is the most frequent type of primary liver cancer. Low numbers of HCC patients being suitable for liver resection or transplantation and multidrug resistance development during pharmacotherapy leads to high death rates for HCC patients. Understanding the molecular mechanisms of HCC etiology may contribute to the development of novel therapeutic strategies for prevention and treatment of HCC. UDP-glucose ceramide glycosyltransferase (UGCG), a key enzyme in glycosphingolipid metabolism, generates glucosylceramide (GlcCer), which is the precursor for all glycosphingolipids (GSLs). Since UGCG gene expression is altered in 0.8% of HCC tumors, GSLs may play a role in cellular processes in liver cancer cells. Here, we discuss the current literature about GSLs and their abundance in normal liver cells, Gaucher disease and HCC. Furthermore, we review the involvement of UGCG/GlcCer in multidrug resistance development, globosides as a potential prognostic marker for HCC, gangliosides as a potential liver cancer stem cell marker, and the role of sulfatides in tumor metastasis. Only a limited number of molecular mechanisms executed by GSLs in HCC are known, which we summarize here briefly. Overall, the role GSLs play in HCC progression and their ability to serve as biomarkers or prognostic indicators for HCC, requires further investigation.


Asunto(s)
Carcinoma Hepatocelular , Neoplasias Hepáticas , Carcinoma Hepatocelular/genética , Resistencia a Múltiples Medicamentos , Glucosilceramidas/metabolismo , Glucosiltransferasas/metabolismo , Glicoesfingolípidos/metabolismo , Glicosiltransferasas/metabolismo , Humanos , Neoplasias Hepáticas/genética
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