RESUMEN
Fuel substrate switching between carbohydrates and fat is essential for maintaining metabolic homeostasis. During aerobic exercise, the predominant energy source gradually shifts from carbohydrates to fat. While it is well known that exercise mobilizes fat storage from adipose tissues, it remains largely obscure how circulating lipids are distributed tissue-specifically according to distinct energy requirements. Here, we demonstrate that aerobic exercise is linked to nutrient availability to regulate tissue-specific activities of lipoprotein lipase (LPL), the key enzyme catabolizing circulating triglyceride (TG) for tissue uptake, through the differential actions of angiopoietin-like (ANGPTL) proteins. Exercise reduced the tissue binding of ANGPTL3 protein, increasing LPL activity and TG uptake in the heart and skeletal muscle in the postprandial state specifically. Mechanistically, exercise suppressed insulin secretion, attenuating hepatic Angptl8 transcription through the PI3K/mTOR/CEBPα pathway, which is imperative for the tissue binding of its partner ANGPTL3. Constitutive expression of ANGPTL8 hampered lipid utilization and resulted in cardiac dysfunction in response to exercise. Conversely, exercise promoted the expression of ANGPTL4 in white adipose tissues, overriding the regulatory actions of ANGPTL8/ANGPTL3 in suppressing adipose LPL activity, thereby diverting circulating TG away from storage. Collectively, our findings show an overlooked bifurcated ANGPTL-LPL network that orchestrates fuel switching in response to aerobic exercise.
Asunto(s)
Proteína 3 Similar a la Angiopoyetina , Proteína 8 Similar a la Angiopoyetina , Proteínas Similares a la Angiopoyetina , Lipoproteína Lipasa , Músculo Esquelético , Periodo Posprandial , Triglicéridos , Proteínas Similares a la Angiopoyetina/metabolismo , Proteínas Similares a la Angiopoyetina/genética , Triglicéridos/metabolismo , Animales , Ratones , Lipoproteína Lipasa/metabolismo , Músculo Esquelético/metabolismo , Proteína 3 Similar a la Angiopoyetina/metabolismo , Masculino , Humanos , Condicionamiento Físico Animal/fisiología , Proteína 4 Similar a la Angiopoyetina/metabolismo , Proteína 4 Similar a la Angiopoyetina/genética , Hormonas Peptídicas/metabolismo , Miocardio/metabolismo , Ejercicio Físico/fisiología , Hígado/metabolismo , Ratones Endogámicos C57BL , Metabolismo de los LípidosRESUMEN
GPIHBP1 is a membrane protein of endothelial cells that transports lipoprotein lipase (LPL), the key enzyme in plasma triglyceride metabolism, from the interstitial space to its site of action on the capillary lumen. An intrinsically disordered highly negatively charged N-terminal domain of GPIHBP1 contributes to the interaction with LPL. In this work, we investigated whether the plethora of heparin-binding proteins with positively charged regions found in human plasma affect this interaction. We also wanted to know whether the role of the N-terminal domain is purely non-specific and supportive for the interaction between LPL and full-length GPIHBP1, or whether it participates in the specific recognition mechanism. Using surface plasmon resonance, affinity chromatography, and FRET, we were unable to identify any plasma component, besides LPL, that bound the N-terminus with detectable affinity or affected its interaction with LPL. By examining different synthetic peptides, we show that the high affinity of the LPL/N-terminal domain interaction is ensured by at least ten negatively charged residues, among which at least six must sequentially arranged. We conclude that the association of LPL with the N-terminal domain of GPIHBP1 is highly specific and human plasma does not contain components that significantly affect this complex.
Asunto(s)
Lipoproteína Lipasa , Unión Proteica , Receptores de Lipoproteína , Lipoproteína Lipasa/metabolismo , Lipoproteína Lipasa/química , Humanos , Receptores de Lipoproteína/metabolismo , Receptores de Lipoproteína/química , Dominios Proteicos , Resonancia por Plasmón de SuperficieRESUMEN
OBJECTIVE: The aim of the study was to examine the expression profile of genes (APOE, FTO, and LPL) associated with metabolic syndrome (MetS) in subjects with concomitant atrial fibrillation (AF). METHODS: A total of 690 subjects were categorized into control, AF without MetS, and AF with MetS. RESULTS: The expression profiles of the APOE, FTO, and LPL genes were decreased in AF subjects and AF subjects with MetS as compared to the controls. In AF without the MetS group, an inverse relationship was found between the expression of the LPL gene with body mass index (BMI) and a positive relationship with creatine kinase-MB, whereas expression of the FTO gene was inversely associated with fasting blood glucose and positively with cardiac troponin I in AF suffering from MetS. Expression of the LPL gene was directly linked with systolic blood pressure (SBP) and high-density lipoprotein-cholesterol (HDL-C), whereas an inverse correlation with heart rate and expression of the FTO gene in AF with MetS were shown. The expression of the LPL gene was inversely related to BMI in subjects with AF. The expression of the LPL gene was positively correlated with SBP and HDL-C and negatively correlated with heart rate, while the expression of the FTO gene was an important predictor of AF with MetS. CONCLUSION: The decreased expression of APOE, FTO, and LPL genes in AF with and without MetS indicates their potential contributing role in the pathogenesis of AF.
Asunto(s)
Dioxigenasa FTO Dependiente de Alfa-Cetoglutarato , Apolipoproteínas E , Fibrilación Atrial , Índice de Masa Corporal , Lipoproteína Lipasa , Síndrome Metabólico , Humanos , Dioxigenasa FTO Dependiente de Alfa-Cetoglutarato/genética , Fibrilación Atrial/genética , Masculino , Femenino , Estudios de Casos y Controles , Apolipoproteínas E/genética , Síndrome Metabólico/genética , Persona de Mediana Edad , Lipoproteína Lipasa/genética , Anciano , HDL-Colesterol/sangre , Presión Sanguínea/genética , Glucemia/análisisRESUMEN
BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a respiratory disorder of obscure etiology and limited treatment options, possibly linked to dysregulation in lipid metabolism. While several observational studies suggest that lipid-lowering agents may decrease the risk of IPF, the evidence is inconsistent. The present Mendelian randomization (MR) study aims to determine the association between circulating lipid traits and IPF and to assess the potential influence of lipid-modifying medications for IPF. METHODS: Summary statistics of 5 lipid traits (high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglyceride, apolipoprotein A, and apolipoprotein B) and IPF were sourced from the UK Biobank and FinnGen Project Round 10. The study's focus on lipid-regulatory genes encompassed PCSK9, NPC1L1, ABCG5, ABCG8, HMGCR, APOB, LDLR, CETP, ANGPTL3, APOC3, LPL, and PPARA. The primary effect estimates were determined using the inverse-variance-weighted method, with additional analyses employing the contamination mixture method, robust adjusted profile score, the weighted median, weighted mode methods, and MR-Egger. Summary-data-based Mendelian randomization (SMR) was used to confirm significant lipid-modifying drug targets, leveraging data on expressed quantitative trait loci in relevant tissues. Sensitivity analyses included assessments of heterogeneity, horizontal pleiotropy, and leave-one-out methods. RESULTS: There was no significant effect of blood lipid traits on IPF risk (all Pï¼0.05). Drug-target MR analysis indicated that genetic mimicry for inhibitor of NPC1L1, PCSK9, ABCG5, ABCG8, and APOC3 were associated with increased IPF risks, with odds ratios (ORs) and 95% confidence intervals (CIs) as follows: 2.74 (1.05-7.12, P = 0.039), 1.36 (1.02-1.82, P = 0.037), 1.66 (1.12-2.45, P = 0.011), 1.68 (1.14-2.48, P = 0.009), and 1.42 (1.20-1.67, P = 3.17×10-5), respectively. The SMR method identified a significant association between PCSK9 gene expression in whole blood and reduced IPF risk (OR = 0.71, 95% CI: 0.50-0.99, P = 0.043). Sensitivity analyses showed no evidence of bias. CONCLUSIONS: Serum lipid traits did not significantly affect the risk of idiopathic pulmonary fibrosis. Drug targets MR studies examining 12 lipid-modifying drugs indicated that PCSK9 inhibitors could dramatically increase IPF risk, a mechanism that may differ from their lipid-lowering actions and thus warrants further investigation.
Asunto(s)
HDL-Colesterol , LDL-Colesterol , Fibrosis Pulmonar Idiopática , Análisis de la Aleatorización Mendeliana , Proproteína Convertasa 9 , Triglicéridos , Humanos , Fibrosis Pulmonar Idiopática/genética , Fibrosis Pulmonar Idiopática/tratamiento farmacológico , Fibrosis Pulmonar Idiopática/sangre , Proproteína Convertasa 9/genética , Triglicéridos/sangre , LDL-Colesterol/sangre , HDL-Colesterol/sangre , Apolipoproteínas B/genética , Apolipoproteínas B/sangre , Transportador de Casete de Unión a ATP, Subfamilia G, Miembro 8/genética , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 5/genética , Proteínas de Transporte de Membrana/genética , Hipolipemiantes/uso terapéutico , Proteínas Similares a la Angiopoyetina/genética , Proteína 3 Similar a la Angiopoyetina , Proteínas de Transferencia de Ésteres de Colesterol/genética , Polimorfismo de Nucleótido Simple , Metabolismo de los Lípidos/efectos de los fármacos , Metabolismo de los Lípidos/genética , Femenino , Lipoproteína Lipasa , Apolipoproteína B-100 , Hidroximetilglutaril-CoA Reductasas , Receptores de LDL , Apolipoproteína C-IIIRESUMEN
BACKGROUND: Lymph node metastasis (LNM) is the primary mode of metastasis in gastric cancer (GC). However, the precise mechanisms underlying this process remain elusive. Tumor cells necessitate lipid metabolic reprogramming to facilitate metastasis, yet the role of lipoprotein lipase (LPL), a pivotal enzyme involved in exogenous lipid uptake, remains uncertain in tumor metastasis. Therefore, the aim of this study was to investigate the presence of lipid metabolic reprogramming during LNM of GC as well as the role of LPL in this process. METHODS: Intracellular lipid levels were quantified using oil red O staining, BODIPY 493/503 staining, and flow cytometry. Lipidomics analysis was employed to identify alterations in intracellular lipid composition following LPL knockdown. Protein expression levels were assessed through immunohistochemistry, Western blotting, and enzyme-linked immunosorbent assays. The mouse popliteal LNM model was utilized to investigate differences in LNM. Immunoprecipitation and mass spectrometry were employed to examine protein associations. In vitro phosphorylation assays and Phos-tag sodium dodecyl-sulfate polyacrylamide gel electrophoresis assays were conducted to detect angiopoietin-like protein 4 (ANGPTL4) phosphorylation. RESULTS: We identified that an elevated intracellular lipid level represents a crucial characteristic of node-positive (N+) GC and further demonstrated that a high-fat diet can expedite LNM. LPL was found to be significantly overexpressed in N+ GC tissues and shown to facilitate LNM by mediating dietary lipid uptake within GC cells. Leptin, an obesity-related hormone, intercepted the effect exerted by ANGPTL4/Furin on LPL cleavage. Circulating leptin binding to the leptin receptor could induce the activation of inositol-requiring enzyme-1 (IRE1) kinase, leading to the phosphorylation of ANGPTL4 at the serine 30 residue and subsequently reducing its binding affinity with LPL. Moreover, our research revealed that LPL disrupted lipid homeostasis by elevating intracellular levels of arachidonic acid, which then triggered the cyclooxygenase-2/prostaglandin E2 (PGE2) pathway, thereby promoting tumor lymphangiogenesis. CONCLUSIONS: Leptin-induced phosphorylation of ANGPTL4 facilitates LPL-mediated lipid uptake and consequently stimulates the production of PGE2, ultimately facilitating LNM in GC.
Asunto(s)
Leptina , Lipoproteína Lipasa , Metástasis Linfática , Neoplasias Gástricas , Lipoproteína Lipasa/metabolismo , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/patología , Humanos , Animales , Ratones , Leptina/metabolismo , Metabolismo de los Lípidos , Masculino , Línea Celular Tumoral , Proteína 4 Similar a la Angiopoyetina/metabolismo , Femenino , FosforilaciónRESUMEN
Sargassum fusiforme is a brown seaweed that grows abundantly along the rocky coastlines of Asian countries. The polysaccharides derived from Sargassum fusiforme (SFPS) have received much interest due to their various bioactivities, such as hypolipidemic, hypoglycemic, and antioxidant activities. In this study, we extracted and purified SFPS, and obtained the ultrasonic degradation product (SFPSUD). The lipid regulatory effects of SFPS and SFPSUD were investigated in a zebrafish model fed a high-fat diet. The results showed that SFPS significantly decreased the levels of total cholesterol (TC) and triglycerides (TG), and increased the activities of lipoprotein lipase (LPL) and hepatic lipase (HL). SFPSUD was more effective than the SFPS in reducing the TC and TG levels in zebrafish, as well as increasing the LPL and HL activities. Histopathological observations of zebrafish livers showed that SFPSUD significantly improved lipid metabolism disorder in the hepatocytes. The possible lipid-lowering mechanism in zebrafish associated with SFPS and SFPSUD may involve acceleration of the lipid metabolism rate by increasing the activities of LPL and HL. Thus, SFPSUD could be tested as a highly effective hypolipidemic drug. Our results suggest that SFPS and SFPSUD have potential uses as functional foods for the prevention and treatment of hyperlipidemia. Ultrasound can be effectively applied to degrade SFPS to improve its physicochemical properties and bioactivities.
Asunto(s)
Dieta Alta en Grasa , Hipolipemiantes , Metabolismo de los Lípidos , Polisacáridos , Sargassum , Pez Cebra , Animales , Sargassum/química , Polisacáridos/farmacología , Polisacáridos/química , Hipolipemiantes/farmacología , Hipolipemiantes/química , Metabolismo de los Lípidos/efectos de los fármacos , Hígado/efectos de los fármacos , Hígado/metabolismo , Hígado/patología , Lipoproteína Lipasa/metabolismo , Triglicéridos/sangre , Triglicéridos/metabolismo , Hiperlipidemias/tratamiento farmacológico , Hiperlipidemias/metabolismo , Colesterol/sangre , Colesterol/metabolismo , Lipasa/metabolismo , Algas ComestiblesRESUMEN
Lipoprotein lipase (LPL) hydrolyzes circulating triglycerides (TGs), releasing fatty acids (FA) and promoting lipid storage in white adipose tissue (WAT). However, the mechanisms regulating adipose LPL and its relationship with the development of hypertriglyceridemia are largely unknown. WAT from obese humans exhibited high PAR2 expression, which was inversely correlated with the LPL gene. Decreased LPL expression was also inversely correlated with elevated plasma TG levels, suggesting that adipose PAR2 might regulate hypertriglyceridemia by downregulating LPL. In mice, aging and high palmitic acid diet (PD) increased PAR2 expression in WAT, which was associated with a high level of macrophage migration inhibitory factor (MIF). MIF downregulated LPL expression and activity in adipocytes by binding with CXCR2/4 receptors and inhibiting Akt phosphorylation. In a MIF overexpression model, high-circulating MIF levels suppressed adipose LPL, and this suppression was associated with increased plasma TGs but not FA. Following PD feeding, adipose LPL expression and activity were significantly reduced, and this reduction was reversed in Par2-/- mice. Recombinant MIF infusion restored high plasma MIF levels in Par2-/- mice, and the levels decreased LPL and attenuated adipocyte lipid storage, leading to hypertriglyceridemia. These data collectively suggest that downregulation of adipose LPL by PAR2/MIF may contribute to the development of hypertriglyceridemia.
Asunto(s)
Regulación hacia Abajo , Hipertrigliceridemia , Lipoproteína Lipasa , Receptor PAR-2 , Animales , Lipoproteína Lipasa/metabolismo , Lipoproteína Lipasa/genética , Hipertrigliceridemia/metabolismo , Hipertrigliceridemia/genética , Ratones , Humanos , Receptor PAR-2/metabolismo , Receptor PAR-2/genética , Masculino , Ratones Noqueados , Triglicéridos/metabolismo , Triglicéridos/sangre , Tejido Adiposo Blanco/metabolismo , Factores Inhibidores de la Migración de Macrófagos/metabolismo , Factores Inhibidores de la Migración de Macrófagos/genética , Adipocitos/metabolismo , Obesidad/metabolismo , Obesidad/genética , Ácido Palmítico/metabolismo , Femenino , Ratones Endogámicos C57BL , Persona de Mediana EdadRESUMEN
INTRODUCTION: This study aims to investigate if a mixture of functional lipids (FLs), containing conjugated linoleic acid (CLA), tocopherols (TPs), and phytosterols (PSs), prevents some lipid alterations induced by high-fat (HF) diets, without adverse effects. METHODS: Male CF1 mice (n = 6/group) were fed (4 weeks) with control (C), HF, or HF + FL diets. RESULTS: FL prevented the overweight induced by the HF diet and reduced the adipose tissue (AT) weight, associated with lower energy efficiency. After the intervention period, the serum triacylglycerol (TAG) levels in both HF diets underwent a decrease associated with an enhanced LPL activity (mainly in muscle). The beneficial effect of the FL mixture on body weight gain and AT weight might be attributed to the decreased lipogenesis, denoted by the lower mRNA levels of SREBP1-c and ACC in AT, as well as by an exacerbated lipid catabolism, reflected by increased mRNA levels of PPARα, ATGL, HSL, and UCP2 in AT. Liver TAG levels were reduced in the HF + FL group due to an elevated lipid oxidation associated with a higher CPT-1 activity and mRNA levels of PPARα and CPT-1a. Moreover, genes linked to fatty acid biosynthesis (SREBP1-c and ACC) showed decreased mRNA levels in both HF diets, this finding being more pronounced in the HF + FL group. CONCLUSION: The administration of an FL mixture (CLA + TP + PS) prevented some lipid alterations induced by a HF diet, avoiding frequent deleterious effects of CLA in mice through the modulation of gene expression related to the regulation of lipid metabolism.
Asunto(s)
Dieta Alta en Grasa , Ácidos Linoleicos Conjugados , Metabolismo de los Lípidos , Hígado , PPAR alfa , Proteína 1 de Unión a los Elementos Reguladores de Esteroles , Triglicéridos , Animales , Dieta Alta en Grasa/efectos adversos , Ratones , Masculino , Triglicéridos/metabolismo , Hígado/metabolismo , Hígado/efectos de los fármacos , Metabolismo de los Lípidos/efectos de los fármacos , PPAR alfa/metabolismo , PPAR alfa/genética , Proteína 1 de Unión a los Elementos Reguladores de Esteroles/metabolismo , Proteína 1 de Unión a los Elementos Reguladores de Esteroles/genética , Ácidos Linoleicos Conjugados/farmacología , Lipogénesis/efectos de los fármacos , Carnitina O-Palmitoiltransferasa/metabolismo , Carnitina O-Palmitoiltransferasa/genética , Proteína Desacopladora 2/metabolismo , Proteína Desacopladora 2/genética , Fitosteroles/farmacología , Tejido Adiposo/metabolismo , Tejido Adiposo/efectos de los fármacos , Aumento de Peso/efectos de los fármacos , Lipoproteína Lipasa/metabolismo , Lipoproteína Lipasa/genéticaRESUMEN
BACKGROUND: The milk's nutritional value is determined by its constituents, including fat, protein, carbohydrates, and minerals. The mammary gland's ability to produce milk is controlled by a complex network of genes. Thereby, the fat, protein, and lactose synthesis must be boost in milk to increase milk production efficiency. This can be accomplished by fusing genetic advancements with proper management practices. Therefore, this study aimed to investigate the association between the Lipoprotein lipase (LPL), kappa casein CSN3, and Glucose transporter 1 (GLUT1) genes expression levels and such milk components as fat, protein, and lactose in different dairy breeds during different stages of lactation. METHODS: To achieve such a purpose, 94 milk samples were collected (72 samples from 36 multiparous black-white and red-white Holstein-Friesian (HF) cows and 22 milk samples from 11 Egyptian buffaloes) during the early and peak lactation stages. The milk samples were utilized for milk analysis and genes expressions analyses using non- invasive approach in obtaining milk fat globules (MFGs) as a source of Ribonucleic acid (RNA). RESULTS: LPL and CSN3 genes expressions levels were found to be significantly higher in Egyptian buffalo than Holstein-Friesian (HF) cows as well as fat and protein percentages. On the other hand, GLUT1 gene expression level was shown to be significantly higher during peak lactation than early lactation. Moreover, lactose % showed a significant difference in peak lactation phase compared to early lactation phase. Also, fat and protein percentages were significantly higher in early lactation period than peak lactation period but lactose% showed the opposite pattern of Egyptian buffalo. CONCLUSION: Total RNA can be successfully obtained from MFGs. The results suggest that these genes play a role in glucose absorption and lactose synthesis in bovine mammary epithelial cells during lactation. Also, these results provide light on the differential expression of these genes among distinct Holstein-Friesian cow breeds and Egyptian buffalo subspecies throughout various lactation phases.
Asunto(s)
Caseínas , Glucolípidos , Glicoproteínas , Lactancia , Gotas Lipídicas , Glándulas Mamarias Animales , Leche , ARN Mensajero , Animales , Bovinos/genética , Lactancia/genética , Femenino , Gotas Lipídicas/metabolismo , Leche/química , Leche/metabolismo , Glucolípidos/metabolismo , Caseínas/genética , Caseínas/metabolismo , Glicoproteínas/genética , Glicoproteínas/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Glándulas Mamarias Animales/metabolismo , Lipoproteína Lipasa/genética , Lipoproteína Lipasa/metabolismo , Transportador de Glucosa de Tipo 1/genética , Transportador de Glucosa de Tipo 1/metabolismo , Búfalos/genética , Búfalos/metabolismo , Lactosa/metabolismo , Lactosa/análisis , Proteínas de la Leche/análisis , Proteínas de la Leche/metabolismo , Proteínas de la Leche/genética , Regulación de la Expresión GénicaRESUMEN
OBJECTIVE: To explore the correlation between asthma risk and genetic variants affecting the expression or function of lipid-lowering drug targets. METHODS: We conducted Mendelian randomization (MR) analyses using variants in several genes associated with lipid-lowering medication targets: HMGCR (statin target), PCSK9 (alirocumab target), NPC1L1 (ezetimibe target), APOB (mipomersen target), ANGPTL3 (evinacumab target), PPARA (fenofibrate target), and APOC3 (volanesorsen target), as well as LDLR and LPL. Our objective was to investigate the relationship between lipid-lowering drugs and asthma through MR. Finally, we assessed the efficacy and stability of the MR analysis using the MR Egger and inverse variance weighted (IVW) methods. RESULTS: The elevated triglyceride (TG) levels associated with the APOC3, and LPL targets were found to increase asthma risk. Conversely, higher LDL-C levels driven by LDLR were found to decrease asthma risk. Additionally, LDL-C levels (driven by APOB, NPC1L1 and HMGCR targets) and TG levels (driven by the LPL target) were associated with improved lung function (FEV1/FVC). LDL-C levels driven by PCSK9 were associated with decreased lung function (FEV1/FVC). CONCLUSION: In conclusion, our findings suggest a likely causal relationship between asthma and lipid-lowering drugs. Moreover, there is compelling evidence indicating that lipid-lowering therapies could play a crucial role in the future management of asthma.
Asunto(s)
Asma , Hipolipemiantes , Análisis de la Aleatorización Mendeliana , Humanos , Asma/genética , Asma/tratamiento farmacológico , Hipolipemiantes/uso terapéutico , Hipolipemiantes/farmacología , Proproteína Convertasa 9/genética , Estudios de Asociación Genética , Pulmón/efectos de los fármacos , Pulmón/patología , Lipoproteína Lipasa/genética , Triglicéridos/sangre , Receptores de LDL/genética , Hidroximetilglutaril-CoA Reductasas/genética , Proteína 3 Similar a la Angiopoyetina , Proteínas Similares a la Angiopoyetina/genética , Apolipoproteína C-III/genética , Apolipoproteínas B/genética , Pruebas de Función Respiratoria , LDL-Colesterol/sangre , Proteínas de Transporte de Membrana , PPAR alfaRESUMEN
With impaired retinal ganglion cell (RGC) function and eventual RGC death, there is a heightened risk of experiencing glaucoma-induced blindness or other optic neuropathies. Poor RGC efficiency leads to limited transmission of visual signals between the retina and the brain by RGC axons. Increased focus on studying lipid messengers found in neurons such as endocannabinoids (eCBs) has importance due to their potential axonal pathway regenerative properties. 2-Arachidonoylglycerol (2-AG), a common eCB, is synthesized from an sn-1 hydrolysis reaction between diacylglycerol (DAG) and diacylglycerol lipase (DAGL). Examination of DAG production allows for future downstream analysis in relation to DAGL functionality. Here, we describe protocol guidelines for extracting RGCs from mouse retinas and subsequent mass spectrometry analysis of the DAG content present within the RGCs.
Asunto(s)
Diglicéridos , Células Ganglionares de la Retina , Transducción de Señal , Células Ganglionares de la Retina/metabolismo , Animales , Ratones , Diglicéridos/metabolismo , Endocannabinoides/metabolismo , Glicéridos/metabolismo , Lipoproteína Lipasa/metabolismo , Ácidos Araquidónicos/metabolismo , Espectrometría de Masas/métodos , Retina/metabolismoRESUMEN
Worldwide, the prevalence of obesity and diabetes have increased, with heart disease being their leading cause of death. Traditionally, the management of obesity and diabetes has focused mainly on weight reduction and controlling high blood glucose. Unfortunately, despite these efforts, poor medication management predisposes these patients to heart failure. One instigator for the development of heart failure is how cardiac tissue utilizes different sources of fuel for energy. In this regard, the heart switches from using various substrates, to predominantly using fatty acids (FA). This transformation to using FA as an exclusive source of energy is helpful in the initial stages of the disease. However, over the progression of diabetes this has grave end results. This is because toxic by-products are produced by overuse of FA, which weaken heart function (heart disease). Lipoprotein lipase (LPL) is responsible for regulating FA delivery to the heart, and its function during diabetes has not been completely revealed. In this review, the mechanisms by which LPL regulates fuel utilization by the heart in control conditions and following diabetes will be discussed in an attempt to identify new targets for therapeutic intervention. Currently, as treatment options to directly target diabetic heart disease are scarce, research on LPL may assist in drug development that exclusively targets fuel utilization by the heart and lipid accumulation in macrophages to help delay, prevent, or treat cardiac failure, and provide long-term management of this condition during diabetes.
Asunto(s)
Enfermedades Cardiovasculares , Lipoproteína Lipasa , Obesidad , Humanos , Lipoproteína Lipasa/metabolismo , Obesidad/tratamiento farmacológico , Obesidad/metabolismo , Enfermedades Cardiovasculares/tratamiento farmacológico , Enfermedades Cardiovasculares/metabolismo , Animales , Diabetes Mellitus/tratamiento farmacológico , Diabetes Mellitus/metabolismo , Ácidos Grasos/metabolismoRESUMEN
Lipoprotein lipase (LPL) is a critical enzyme in humans that provides fuel to peripheral tissues. LPL hydrolyzes triglycerides from the cores of lipoproteins that are circulating in plasma and interacts with receptors to mediate lipoprotein uptake, thus directing lipid distribution via catalytic and non-catalytic functions. Functional losses in LPL or any of its myriad of regulators alter lipid homeostasis and potentially affect the risk of developing cardiovascular disease-either increasing or decreasing the risk depending on the mutated protein. The extensive LPL regulatory network tunes LPL activity to allocate fatty acids according to the energetic needs of the organism and thus is nutritionally responsive and tissue dependent. Multiple pharmaceuticals in development manipulate or mimic these regulators, demonstrating their translational importance. Another facet of LPL biology is that the oligomeric state of the enzyme is also central to its regulation. Recent structural studies have solidified the idea that LPL is regulated not only by interactions with other binding partners but also by self-associations. Here, we review the complexities of the protein-protein and protein-lipid interactions that govern LPL structure and function.
Asunto(s)
Lipoproteína Lipasa , Lipoproteína Lipasa/metabolismo , Lipoproteína Lipasa/química , Lipoproteína Lipasa/genética , Humanos , Animales , Unión Proteica , Triglicéridos/metabolismo , Metabolismo de los LípidosRESUMEN
Apolipoprotein AV (APOA5) deficiency causes hypertriglyceridemia in mice and humans. For years, the cause remained a mystery, but the mechanisms have now come into focus. Here, we review progress in defining APOA5's function in plasma triglyceride metabolism. Biochemical studies revealed that APOA5 binds to the angiopoietin-like protein 3/8 complex (ANGPTL3/8) and suppresses its ability to inhibit the activity of lipoprotein lipase (LPL). Thus, APOA5 deficiency is accompanied by increased ANGPTL3/8 activity and lower levels of LPL activity. APOA5 deficiency also reduces amounts of LPL in capillaries of oxidative tissues (e.g., heart, brown adipose tissue). Cell culture experiments revealed the likely explanation: ANGPTL3/8 detaches LPL from its binding sites on the surface of cells, and that effect is blocked by APOA5. Both the low intracapillary LPL levels and the high plasma triglyceride levels in Apoa5-/- mice are normalized by recombinant APOA5. Carboxyl-terminal sequences in APOA5 are crucial for its function; a mutant APOA5 lacking 40-carboxyl-terminal residues cannot bind to ANGPTL3/8 and lacks the ability to change intracapillary LPL levels or plasma triglyceride levels in Apoa5-/- mice. Also, an antibody against the last 26 amino acids of APOA5 reduces intracapillary LPL levels and increases plasma triglyceride levels in wild-type mice. An inhibitory ANGPTL3/8-specific antibody functions as an APOA5-mimetic reagent, increasing intracapillary LPL levels and lowering plasma triglyceride levels in both Apoa5-/- and wild-type mice. That antibody is a potentially attractive strategy for treating elevated plasma lipid levels in human patients.
Asunto(s)
Apolipoproteína A-V , Hipertrigliceridemia , Lipoproteína Lipasa , Animales , Lipoproteína Lipasa/metabolismo , Lipoproteína Lipasa/genética , Humanos , Hipertrigliceridemia/metabolismo , Hipertrigliceridemia/genética , Apolipoproteína A-V/genética , Apolipoproteína A-V/metabolismo , Capilares/metabolismo , Ratones , Triglicéridos/metabolismo , Triglicéridos/sangreRESUMEN
OBJECTIVES: This study explored the association of deleterious variants in pharmacodynamics (PD) genes with statin response and adverse effects in patients with familial hypercholesterolemia (FH) and analyzed their potential effects on protein structure and stability. METHODS: Clinical and laboratory data were obtained from 144 adult FH patients treated with statins. A panel of 32 PD genes was analyzed by exon-targeted gene sequencing. Deleterious variants were identified using prediction algorithms and their structural effects were analyzed by molecular modeling studies. RESULTS: A total of 102 variants were predicted as deleterious (83 missense, 8 stop-gain, 4 frameshift, 1 indel, 6 splicing). The variants ABCA1 rs769705621 (indel), LPA rs41267807 (p.Tyr2023Cys) and KIF6 rs20455 (p.Trp719Arg) were associated with reduced low-density lipoprotein cholesterol (LDLc) response to statins, and the LPL rs1801177 (p.Asp36Asn) with increased LDLc response (P < 0.05). LPA rs3124784 (p.Arg2016Cys) was predicted to increase statin response (P = 0.022), and ABCA1 rs769705621 to increase the risk of statin-related adverse events (SRAE) (P = 0.027). LPA p.Arg2016Cys and LPL p.Asn36Asp maintained interactions with solvent, LPA p.Tyr2023Cys reduced intramolecular interaction with Gln1987, and KIF6 p.Trp719Arg did not affect intramolecular interactions. DDMut analysis showed that LPA p.Arg2016Cys and p.Tyr2023Cys and LPL p.Asp36Asn caused energetically favorable changes, and KIF6 p.Trp719Arg resulted in unfavorable energetic changes, affecting protein stability. CONCLUSION: Deleterious variants in ABCA1, LPA, LPL and KIF6 are associated with variability in LDLc response to statins, and ABCA1 rs769705621 is associated with SRAE risk in FH patients. Molecular modeling studies suggest that LPA p.Tyr2023Cys and KIF6 p.Trp719Arg disturb protein conformational structure and stability.
Asunto(s)
Humanos , Masculino , Femenino , Adulto , Persona de Mediana Edad , Inhibidores de Hidroximetilglutaril-CoA Reductasas , Transportador 1 de Casete de Unión a ATP , Hiperlipoproteinemia Tipo II , Lipoproteína LipasaRESUMEN
Stem cells demonstrate differentiation and regulatory functions. In this discussion, we will explore the impacts of cell culture density on stem cell proliferation, adipogenesis, and regulatory abilities. This study aimed to investigate the impact of the initial culture density of human periodontal ligament stem cells (hPDLSCs) on the adipogenic differentiation of autologous cells. Our findings indicate that the proliferation rate of hPDLSCs increased with increasing initial cell density (0.5-8 × 104 cells/cm2). After adipogenic differentiation induced by different initial cell densities of hPDLSC, we found that the mean adipose concentration and the expression levels of lipoprotein lipase (LPL), CCAAT/enhancer binding protein α (CEBPα), and peroxisome proliferator-activated receptor γ (PPAR-γ) genes all increased with increasing cell density. To investigate the regulatory role of hPDLSCs in the adipogenic differentiation of other cells, we used secreted exocrine vesicles derived from hPDLSCs cultivated at different initial cell densities of 50 µg/mL to induce the adipogenic differentiation of human bone marrow stromal cells. We also found that the mean adipose concentration and expression of LPL, CEBPα, and PPARγ genes increased with increasing cell density, with an optimal culture density of 8 × 104 cells/cm2. This study provides a foundation for the application of adipogenic differentiation in stem cells.
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Adipogénesis , Diferenciación Celular , Ligamento Periodontal , Células Madre , Humanos , Ligamento Periodontal/citología , Ligamento Periodontal/metabolismo , Células Madre/citología , Células Madre/metabolismo , PPAR gamma/metabolismo , PPAR gamma/genética , Células Madre Mesenquimatosas/metabolismo , Células Madre Mesenquimatosas/citología , Células Cultivadas , Lipoproteína Lipasa/metabolismo , Lipoproteína Lipasa/genética , Proliferación Celular , Recuento de Células , Proteína alfa Potenciadora de Unión a CCAAT/metabolismo , Proteína alfa Potenciadora de Unión a CCAAT/genéticaRESUMEN
Introduction: Hypertriglyceridemia (HTG) is a complex disorder caused by genetic and environmental factors that frequently results from loss-of-function variants in the gene encoding lipoprotein lipase (LPL). Heterozygous patients have a range of symptoms, while homozygous LPL deficiency presents with severe symptoms including acute pancreatitis, xanthomas, and lipemia retinalis. Methods: We described the clinical characteristics of three Slovenian patients (an 8-year-old female, an 18-year-old man, and a 57-year-old female) and one Pakistani patient (a 59-year-old male) with LPL deficiency. We performed next-generation sequencing (NGS) targeting all coding exons and intron-exon boundaries of the LPL gene, and Sanger sequencing for variant confirmation. In addition, we performed a systematic literature review of all cases with three identified variants and described their clinical characteristics. Results: Two Slovenian patients with a heterozygous pathogenic variant NM_000237.3:c.984G>T (p.Met328Ile) were diagnosed within the first three years of life and had triglyceride (TG) values of 16 and 20 mmol/L. An asymptomatic Pakistani patient with TG values of 36.8 mmol/L until the age of 44 years, was identified as heterozygous for a pathogenic variant NM_000237.3:c.724G>A (p.Asp242Asn). His TG levels dropped to 12.7 mmol/L on dietary modifications and by using fibrates. A Slovenian patient who first suffered from pancreatitis at the age of 18 years with a TG value of 34 mmol/L was found to be homozygous for NM_000237.3:c.337T>C (p.Trp113Arg). Conclusions: Patients with LPL deficiency had high TG levels at diagnosis. Homozygous patients had worse outcomes. Good diet and medication compliance can reduce severity.
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Lipoproteína Lipasa , Humanos , Masculino , Femenino , Eslovenia/epidemiología , Adolescente , Persona de Mediana Edad , Lipoproteína Lipasa/genética , Lipoproteína Lipasa/deficiencia , Niño , Pakistán/epidemiología , Hiperlipoproteinemia Tipo I/genética , MutaciónRESUMEN
BACKGROUND: Pathogenic variants in PLIN1-encoding PLIN1 (perilipin-1) are responsible for an autosomal dominant form of familial partial lipodystrophy (FPL) associated with severe insulin resistance, hepatic steatosis, and important hypertriglyceridemia. This study aims to decipher the mechanisms of hypertriglyceridemia associated with PLIN1-related FPL. METHODS: We performed an in vivo lipoprotein kinetic study in 6 affected patients compared with 13 healthy controls and 8 patients with type 2 diabetes. Glucose and lipid parameters, including plasma LPL (lipoprotein lipase) mass, were measured. LPL mRNA and protein expression were evaluated in abdominal subcutaneous adipose tissue from patients with 5 PLIN1-mutated FPL and 3 controls. RESULTS: Patients with PLIN1-mutated FPL presented with decreased fat mass, insulin resistance, and diabetes (glycated hemoglobin A1c, 6.68±0.70% versus 7.48±1.63% in patients with type 2 diabetes; mean±SD; P=0.27). Their plasma triglycerides were higher (5.96±3.08 mmol/L) than in controls (0.76±0.27 mmol/L; P<0.0001) and patients with type 2 diabetes (2.94±1.46 mmol/L, P=0.006). Compared with controls, patients with PLIN1-related FPL had a significant reduction of the indirect fractional catabolic rate of VLDL (very-low-density lipoprotein)-apoB100 toward IDL (intermediate-density lipoprotein)/LDL (low-density lipoprotein; 1.79±1.38 versus 5.34±2.45 pool/d; P=0.003) and the indirect fractional catabolic rate of IDL-apoB100 toward LDL (2.14±1.44 versus 7.51±4.07 pool/d; P=0.005). VLDL-apoB100 production was not different between patients with PLIN1-related FPL and controls. Compared with patients with type 2 diabetes, patients with PLIN1-related FPL also showed a significant reduction of the catabolism of both VLDL-apoB100 (P=0.031) and IDL-apoB100 (P=0.031). Plasma LPL mass was significantly lower in patients with PLIN1-related FPL than in controls (21.03±10.08 versus 55.76±13.10 ng/mL; P<0.0001), although the LPL protein expression in adipose tissue was similar. VLDL-apoB100 and IDL-apoB100 indirect fractional catabolic rates were negatively correlated with plasma triglycerides and positively correlated with LPL mass. CONCLUSIONS: We show that hypertriglyceridemia associated with PLIN1-related FPL results from a marked decrease in the catabolism of triglyceride-rich lipoproteins (VLDL and IDL). This could be due to a pronounced reduction in LPL availability, related to the decreased adipose tissue mass.
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Diabetes Mellitus Tipo 2 , Hipertrigliceridemia , Resistencia a la Insulina , Lipodistrofia Parcial Familiar , Lipoproteína Lipasa , Lipoproteínas , Perilipina-1 , Triglicéridos , Humanos , Masculino , Perilipina-1/genética , Perilipina-1/metabolismo , Perilipina-1/sangre , Triglicéridos/sangre , Hipertrigliceridemia/sangre , Hipertrigliceridemia/genética , Femenino , Adulto , Persona de Mediana Edad , Estudios de Casos y Controles , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/complicaciones , Lipoproteínas/sangre , Lipoproteína Lipasa/sangre , Lipoproteína Lipasa/metabolismo , Lipoproteína Lipasa/genética , Lipodistrofia Parcial Familiar/genética , Lipodistrofia Parcial Familiar/sangre , Lipodistrofia Parcial Familiar/metabolismo , Mutación , Glucemia/metabolismo , Lipoproteínas VLDL/sangre , Lipoproteínas VLDL/metabolismo , Biomarcadores/sangre , Fenotipo , Predisposición Genética a la Enfermedad , Lipólisis , ARN Mensajero/metabolismo , ARN Mensajero/genéticaRESUMEN
The endocannabinoid system (ECS) regulates neurotransmission linked to synaptic plasticity, cognition, and emotion. While it has been demonstrated that dysregulation of the ECS in adulthood is relevant not only to central nervous system (CNS) disorders such as autism spectrum disorder, cognitive dysfunction, and depression but also to brain function, there are few studies on how dysregulation of the ECS in the neonatal period affects the manifestation and pathophysiology of CNS disorders later in life. In this study, DO34, a diacylglycerol lipase alpha (DAGLα) inhibitor affecting endocannabinoid 2-AG production, was injected into C57BL/6N male mice from postnatal day (PND) 7 to PND 10, inducing dysregulation of the ECS in the neonatal period. Subsequently, we examined whether it affects neuronal function in adulthood through electrophysiological and behavioral evaluation. DO34-injected mice showed significantly decreased cognitive functions, attributed to impairment of hippocampal synaptic plasticity. The findings suggest that regulation of ECS activity in the neonatal period may induce enduring effects on adult brain function.