RESUMO
Atypical or second-generation antipsychotics are used in the treatment of psychosis and behavioral problems in older persons with dementia. However, these pharmaceutical drugs are associated with an increased risk of stroke in such patients. In this study, we evaluated the effects of risperidone treatment on phospholipid and sphingolipid composition and lipid raft function in peripheral blood mononuclear cells (PBMCs) of older patients (mean age >88 years). The results showed that the levels of dihydroceramides, very-long-chain ceramides, and lysophosphatidylcholines decreased in PBMCs of the risperidone-treated group compared with untreated controls. These findings were confirmed by in vitro assays using human THP-1 monocytes. The reduction in the levels of very-long-chain ceramides and dihydroceramides could be due to the decrease in the expression of fatty acid elongase 3, as observed in THP-1 monocytes. Moreover, risperidone disrupted lipid raft domains in the plasma membrane of PBMCs. These results indicated that risperidone alters phospholipid and sphingolipid composition and lipid raft domains in PBMCs of older patients, potentially affecting multiple signaling pathways associated with these membrane domains.
Assuntos
Ceramidas/metabolismo , Metabolismo dos Lipídeos/efeitos dos fármacos , Transtornos Psicóticos/tratamento farmacológico , Idoso , Idoso de 80 Anos ou mais , Antipsicóticos/farmacologia , Membrana Celular/genética , Membrana Celular/metabolismo , Feminino , Humanos , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/metabolismo , Metabolismo dos Lipídeos/genética , Lisofosfolipídeos/genética , Masculino , Olanzapina/farmacologia , Transtornos Psicóticos/sangue , Transtornos Psicóticos/patologia , Risperidona/farmacologia , Esfingolipídeos/genéticaRESUMO
Experimental autoimmune encephalomyelitis (EAE), the most common model for multiple sclerosis, is characterized by inflammatory cell infiltration into the central nervous system and demyelination. Previous studies have demonstrated that administration of some polyphenols may reduce the neurological alterations of EAE. In this work, we show that ellagic acid, a polyphenolic compound, is beneficial in EAE, most likely through stimulation of ceramide biosynthesis within the brain. EAE was induced in Lewis rats by injection of guinea-pig spinal cord tissue along with Freund's complete adjuvant containing Mycobacterium tuberculosis. Clinical signs first appeared at day 8 post-immunization and reached a peak within 3â¯days, coincident with reduction of myelin basic protein (MBP) in the cortex. Sphingolipids, the other major components of myelin, also decreased at the acute phase of EAE, both in the cerebral cortex and in the spinal cord. In rats receiving ellagic acid in the drinking water from 2â¯days before immunization, the onset of the disease was delayed and clinical signs were reduced. This amelioration of clinical signs was accompanied by sustained levels of both MBP and sphingolipid in the cortex, without apparent changes in infiltration of inflammatory CD3+ T-cells, microglial activation, or weight loss, which together suggest a neuroprotective effect of ellagic acid. Finally, in glioma and oligodendroglioma cells we demonstrate that urolithins, the ellagic acid metabolites that circulate in plasma, stimulate the synthesis of ceramide. Together these data suggest that ellagic acid consumption protects against demyelination in rats with induced EAE, likely by a mechanism involving sphingolipid synthesis.
Assuntos
Anti-Inflamatórios/farmacologia , Ceramidas/agonistas , Ácido Elágico/farmacologia , Encefalomielite Autoimune Experimental/tratamento farmacológico , Bainha de Mielina/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Animais , Linhagem Celular Tumoral , Ceramidas/biossíntese , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/metabolismo , Córtex Cerebral/patologia , Cumarínicos/metabolismo , Cumarínicos/farmacologia , Encefalomielite Autoimune Experimental/metabolismo , Encefalomielite Autoimune Experimental/patologia , Feminino , Adjuvante de Freund/administração & dosagem , Expressão Gênica , Cobaias , Mycobacterium tuberculosis/química , Proteína Básica da Mielina/agonistas , Proteína Básica da Mielina/genética , Proteína Básica da Mielina/metabolismo , Bainha de Mielina/metabolismo , Bainha de Mielina/patologia , Neuroglia/efeitos dos fármacos , Neuroglia/metabolismo , Neuroglia/patologia , Oligodendroglia/efeitos dos fármacos , Oligodendroglia/metabolismo , Oligodendroglia/patologia , Ratos , Ratos Endogâmicos Lew , Medula Espinal/efeitos dos fármacos , Medula Espinal/metabolismo , Medula Espinal/patologiaRESUMO
First- and second-generation antipsychotics (FGAs and SGAs, respectively), have the ability to inhibit cholesterol biosynthesis and also to interrupt the intracellular cholesterol trafficking, interfering with low-density lipoprotein (LDL)-derived cholesterol egress from late endosomes/lysosomes. In the present work, we examined the effects of FGA haloperidol on the functionality of late endosomes/lysosomes in vitro. In HepG2 hepatocarcinoma cells incubated in the presence of 1,1'-dioctadecyl-3,3,3,3'-tetramethylindocarbocyanineperchlorate (DiI)-LDL, treatment with haloperidol caused the enlargement of organelles positive for late endosome markers lysosome-associated membrane protein 2 (LAMP-2) and LBPA (lysobisphosphatidic acid), which also showed increased content of both free-cholesterol and DiI derived from LDL. This indicates the accumulation of LDL-lipids in the late endosomal/lysosomal compartment caused by haloperidol. In contrast, LDL traffic through early endosomes and the Golgi apparatus appeared to be unaffected by the antipsychotic as the distribution of both early endosome antigen 1 (EEA1) and coatomer subunit ß (ß-COP) were not perturbed. Notably, treatment with haloperidol significantly increased the lysosomal pH and decreased the activities of lysosomal protease and ß-d-galactosidase in a dose-dependent manner. We conclude that the alkalinization of the lysosomes' internal milieu induced by haloperidol affects lysosomal functionality.
Assuntos
Antipsicóticos/farmacologia , Endossomos/efeitos dos fármacos , Haloperidol/farmacologia , Lisossomos/efeitos dos fármacos , Antipsicóticos/efeitos adversos , Colesterol/metabolismo , Endossomos/metabolismo , Haloperidol/efeitos adversos , Células Hep G2 , Humanos , Concentração de Íons de Hidrogênio , Metabolismo dos Lipídeos , Lisofosfolipídeos/metabolismo , Proteína 2 de Membrana Associada ao Lisossomo/metabolismo , Lisossomos/metabolismo , Peptídeo Hidrolases/metabolismo , beta-Galactosidase/metabolismoRESUMO
Haloperidol, a typical antipsychotic, has been shown to inhibit cholesterol biosynthesis by affecting Δ(7)-reductase, Δ(8,7)-isomerase, and Δ(14)-reductase activities, which results in the accumulation of different sterol intermediates. In the present work, we investigated the effects of atypical or second-generation antipsychotics (SGA), such as clozapine, risperidone, and ziprasidone, on intracellular lipid metabolism in different cell lines. All the SGAs tested inhibited cholesterol biosynthesis. Ziprasidone and risperidone had the same targets as haloperidol at inhibiting cholesterol biosynthesis, although with different relative activities (ziprasidone > haloperidol > risperidone). In contrast, clozapine mainly affected Δ(24)-reductase and Δ(8,7)-isomerase activities. These amphiphilic drugs also interfered with the LDL-derived cholesterol egress from the endosome/lysosome compartment, thus further reducing the cholesterol content in the endoplasmic reticulum. This triggered a homeostatic response with the stimulation of sterol regulatory element-binding protein (SREBP)-regulated gene expression. Treatment with SGAs also increased the synthesis of complex lipids (phospholipids and triacylglycerides). Once the antipsychotics were removed from the medium, a rebound in the cholesterol biosynthesis rate was detected, and the complex-lipid synthesis further increased. In this condition, apolipoprotein B secretion was also stimulated as demonstrated in HepG2 cells. These effects of SGAs on lipid homeostasis may be relevant in the metabolic side effects of antipsychotics, especially hypertriglyceridemia.
Assuntos
Antipsicóticos/farmacologia , Colesterol/metabolismo , Ácidos Graxos/metabolismo , Acetatos/metabolismo , Apolipoproteína B-100/metabolismo , Transporte Biológico/efeitos dos fármacos , Linhagem Celular Tumoral , Colesterol/biossíntese , LDL-Colesterol/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Homeostase/efeitos dos fármacos , Humanos , Espaço Intracelular/efeitos dos fármacos , Espaço Intracelular/metabolismoRESUMO
Exosomes/microvesicles originate from multivesicular bodies that allow the secretion of endolysosome components out of the cell. In the present work, we investigated the effects of rottlerin, a polyphenol, on exosome/microvesicle secretion in a model of intracellular lipid trafficking impairment, and elucidated the mechanism of action. In a model of lipid trafficking impairment in C6 glia cells, rottlerin increased ceramide levels, while decreasing hexosylceramide content. This was accompanied by increased exosome/microvesicle secretion, thereby reducing the concentration of lipids in the endolysosomal compartment. The reduction of hexosylceramide levels by rottlerin was attributed to the increase of ß-glucosidase (glucosylceramidase) activity, and the effects of rottlerin were abrogated by ß-glucosidase inhibitors such as isofagomine D-tartrate and AMP-deoxynojirimycin. Moreover, treatment with ML-266, a potent activator of the ß-glucosidase enzyme, recapitulated the effects of rottlerin on the sphingolipid profile and exosome/microvesicle secretion. Finally, inhibition of AMPK (AMP-activated protein kinase) using compound C prevented both exosome/microvesicle secretion and the elimination of endolysosome lipids, which were promoted by rottlerin. The results showed that the decrease in intracellular lipid deposition induced by rottlerin was mediated by ß-glucosidase activation and exosome/microvesicle release via the AMPK pathway. Rottlerin consumption could represent an additional health benefit in lysosomal deposition diseases.
RESUMO
Curcumin, a hydrophobic polyphenol found in the rhizome of Curcuma longa, has been shown to reduce intracellular lipid accumulation in mouse models of lysosomal storage diseases such as Niemann-Pick type C. Exosomes are small extracellular vesicles secreted by cells in response to changes in intracellular ceramide composition. Curcumin can induce exosome/microvesicle release in cellular models of lipid deposition; however, the mechanism by which curcumin stimulates this release is unknown. In a model of lipid trafficking impairment in C6 glia cells, we show that curcumin stimulated ceramide synthesis by increasing the intracellular concentration of ceramide-dihydroceramide. Ceramide overload increased exosome/microvesicle secretion 10-fold, thereby reducing the concentration of lipids in the endolysosomal compartment. These effects were blocked by inhibitors of serine palmitoyltransferase (myriocin) and ceramide synthase (fumonisin B1). It is concluded that the decrease in intracellular lipid deposition induced by curcumin is mediated by increased ceramide synthesis and exosome/microvesicle release. This action may represent an additional health benefit of curcumin.
Assuntos
Micropartículas Derivadas de Células/efeitos dos fármacos , Ceramidas/biossíntese , Curcumina/farmacologia , Exossomos/efeitos dos fármacos , Neuroglia/efeitos dos fármacos , Animais , Linhagem Celular Tumoral , Micropartículas Derivadas de Células/metabolismo , Exossomos/metabolismo , Ácidos Graxos Monoinsaturados/farmacologia , Fumonisinas/farmacologia , Humanos , Metabolismo dos Lipídeos/efeitos dos fármacos , Lipoproteínas LDL/metabolismo , Lisossomos/efeitos dos fármacos , Lisossomos/metabolismo , Neuroglia/citologia , Neuroglia/metabolismo , Neuroglia/patologia , Doença de Niemann-Pick Tipo C/dietoterapia , Doença de Niemann-Pick Tipo C/patologia , Oxirredutases/antagonistas & inibidores , Oxirredutases/metabolismo , Ratos , Serina C-Palmitoiltransferase/antagonistas & inibidores , Serina C-Palmitoiltransferase/metabolismoRESUMO
SCOPE: First- and second-generation antipsychotics (FGAs and SGAs, respectively), both inhibit cholesterol biosynthesis and impair the intracellular cholesterol trafficking, leading to lipid accumulation in the late endosome/lysosome compartment. In this study we examined if curcumin, a plant polyphenol that stimulates exosome release, can alleviate antipsychotic-induced intracellular lipid accumulation. METHODS: HepG2 hepatocarcinoma cells were treated with antipsychotics or placebo and DiI-labelled LDL for 18 h and then exposed to curcumin for the last 2 h. Cells and media were collected separately and used for biochemical analyses, electron microscopy and immunocytochemistry. Exosomes were isolated from the incubation medium by ultracentrifugation. RESULTS: Curcumin treatment reduced the number of heterolysosomes and shifted their subcellular localization to the periphery, as revealed by electron microscopy, and stimulated the release of lysosomal ß-hexosaminidase and exosome markers flotillin-2 and CD63 into the media. The presence of DiI in exosomes released by cells preloaded with DiI-LDL demonstrated the endolysosomal origin of the microvesicles. Furthermore, curcumin increased the secretion of cholesterol as well as LDL-derived DiI and [3H]-cholesterol, in association with a decrease of intracellular lipids. Thus, the disruption of lipid trafficking induced by FGAs or SGAs can be relieved by curcumin treatment. This polyphenol, however, did not mitigate the reduction of cholesterol esterification induced by antipsychotics. CONCLUSION: Curcumin stimulates exosome release to remove cholesterol (and presumably other lipids) accumulated within the endolysosomal compartment, thereby normalizing intracellular lipid homeostasis. This action may help minimize the adverse metabolic effects of antipsychotic treatment, which should now be evaluated in clinical trials.
Assuntos
Antipsicóticos/efeitos adversos , Colesterol/metabolismo , Curcumina/farmacologia , Exocitose/efeitos dos fármacos , Exossomos/efeitos dos fármacos , Exossomos/metabolismo , Células Hep G2 , Humanos , Metabolismo dos Lipídeos/efeitos dos fármacos , Lisossomos/efeitos dos fármacos , Lisossomos/metabolismoRESUMO
SCOPE: Exosomes/microvesicles are originated from multivesicular bodies that allow the secretion of endolysosome components out of the cell. In the present work, we investigated the effects of curcumin, a polyphenol, on exosomes/microvesicles secretion in different cells lines, using U18666A as a model of intracellular cholesterol trafficking impairment. METHODS AND RESULTS: In both HepG2 hepatocarcinoma cells and THP-1 differentiated macrophages, treatment with curcumin affected the size and the localization of endosome/lysosomes accumulated by U18666A, and reduced the cholesterol cell content. To ascertain the mechanism, we analyzed the incubation medium. Curcumin stimulated the release of cholesterol and the lysosomal ß-hexosaminidase enzyme, as well as the exosome markers, flotillin-2 and CD63. Electron microscopy studies demonstrated the presence of small vesicles similar to exosomes/microvesicles in the secretion fluid. These vesicles harbored CD63 on their surface, indicative of their endolysosomal origin. These effects of curcumin were particularly intense in cells treated with U18666A. CONCLUSION: These findings indicate that curcumin ameliorates the U18666A-induced endolysosomal cholesterol accumulation by shuttling cholesterol and presumably other lipids out of the cell via exosomes/microvesicles secretion. This action may contribute to the potential of curcumin in the treatment of lysosomal storage diseases.