RÉSUMÉ
Lipid homeostasis is crucial for proper cellular and systemic functions. A growing number of studies confirm the importance of lipid homeostasis in diabetic kidney disease (DKD). Lipotoxicity caused by imbalance in renal lipid homeostasis can further exasperate renal injury. Large lipid deposits and lipid droplet accumulation are present in the kidneys of DKD patients. Autophagy plays a critical role in DKD lipid homeostasis and is involved in the regulation of lipid content. Inhibition or reduction of autophagy can lead to lipid accumulation, which in turn further affects autophagy. Lipophagy selectively recognizes and degrades lipids and helps to regulate cellular lipid metabolism and maintain intracellular lipid homeostasis. Therefore, we provide a systematic review of fatty acid, cholesterol, and sphingolipid metabolism, and discuss the responses of different renal intrinsic cells to imbalances in lipid homeostasis. Finally, we discuss the mechanism by which autophagy, especially lipophagy, maintains lipid homeostasis to support the development of new DKD drugs targeting lipid homeostasis.
Sujet(s)
Autophagie , Néphropathies diabétiques , Homéostasie , Métabolisme lipidique , Humains , Néphropathies diabétiques/métabolisme , Métabolisme lipidique/physiologie , Autophagie/physiologie , Animaux , Cholestérol/métabolisme , Acides gras/métabolisme , Sphingolipides/métabolisme , Rein/métabolismeRÉSUMÉ
We performed a comprehensive study of protein (total protein, medium-molecular-weight peptides, creatinine, and urea), purine (uric acid), and lipid (cholesterol, triglycerides) metabolism, activity of AST, ALT, and acid phosphatase in blood plasma of white male rats under conditions of restriction of motor activity up to 28 days. Patterns of changes in metabolic profile during hypokinesia were established: prevalence of catabolic processes and atherogenic shifts in the lipid spectrum with maximum manifestation on 14-21 days of the experiment.
Sujet(s)
Cholestérol , Triglycéride , Animaux , Mâle , Rats , Triglycéride/sang , Triglycéride/métabolisme , Cholestérol/sang , Cholestérol/métabolisme , Acide urique/sang , Acide urique/métabolisme , Activité motrice/physiologie , Métabolome/physiologie , Métabolisme lipidique/physiologie , Aspartate aminotransferases/sang , Aspartate aminotransferases/métabolisme , Alanine transaminase/sang , Alanine transaminase/métabolisme , Créatinine/sang , Acid phosphatase/métabolisme , Acid phosphatase/sang , Urée/sang , Hypocinésie/métabolisme , Hypocinésie/physiopathologieRÉSUMÉ
Transient Receptor Potential Vanilloid 1 (TRPV1) plays a central role in pain sensation and is thus an attractive pharmacological drug target. SAF312 is a potent, selective, and non-competitive antagonist of TRPV1 and shows promising potential in treating ocular surface pain. However, the precise mechanism by which SAF312 inhibits TRPV1 remains poorly understood. Here, we present the cryo-EM structure of human TRPV1 in complex with SAF312, elucidating the structural foundation of its antagonistic effects on TRPV1. SAF312 binds to the vanilloid binding pocket, preventing conformational changes in S4 and S5 helices, which are essential for channel gating. Unexpectedly, a putative cholesterol was found to contribute to SAF312's inhibition. Complemented by mutagenesis experiments and molecular dynamics simulations, our research offers substantial mechanistic insights into the regulation of TRPV1 by SAF312, highlighting the interplay between the antagonist and cholesterol in modulating TRPV1 function. This work not only expands our understanding of TRPV1 inhibition by SAF312 but also lays the groundwork for further developments in the design and optimization of TRPV1-related therapies.
Sujet(s)
Cholestérol , Cryomicroscopie électronique , Simulation de dynamique moléculaire , Canaux cationiques TRPV , Canaux cationiques TRPV/métabolisme , Canaux cationiques TRPV/antagonistes et inhibiteurs , Canaux cationiques TRPV/composition chimique , Canaux cationiques TRPV/génétique , Cholestérol/métabolisme , Humains , Sites de fixation , Cellules HEK293 , Liaison aux protéinesRÉSUMÉ
Cholesterol is required to maintain the functional integrity of cellular membrane systems and signalling pathways, but its supply must be closely and dynamically regulated because excess cholesterol is toxic. Sterol regulatory element-binding protein 2 (SREBP2) and the ER-resident protein HMG-CoA reductase (HMGCR) are key regulators of cholesterol biosynthesis. Here, we assessed the mechanistic aspects of their regulation in hepatic cells. Unexpectedly, we found that the transcriptionally active fragment of SREBP2 (N-SREBP2) was produced constitutively. Moreover, in the absence of an exogenous cholesterol supply, nuclear N-SREBP2 became resistant to proteasome-mediated degradation. This resistance was paired with increased occupancy at the HMGCR promoter and HMGCR expression. Inhibiting nuclear N-SREBP2 degradation did not increase HMGCR RNA levels; this increase required cholesterol depletion. Our findings, combined with previous physiological and biophysical investigations, suggest a new model of SREBP2-mediated regulation of cholesterol biosynthesis in the organ that handles large and rapid fluctuations in the dietary supply of this key lipid. Specifically, in the nucleus, cholesterol and the ubiquitin-proteasome system provide a short-loop system that modulates the rate of cholesterol biosynthesis via regulation of nuclear N-SREBP2 turnover and HMGCR expression. Our findings have important implications for maintaining cellular cholesterol homeostasis and lowering blood cholesterol via the SREBP2-HMGCR axis.
Sujet(s)
Cholestérol , Homéostasie , Hydroxymethylglutaryl-CoA reductases , Protéine-2 de liaison à l'élément de régulation des stérols , Protéine-2 de liaison à l'élément de régulation des stérols/métabolisme , Cholestérol/métabolisme , Humains , Hydroxymethylglutaryl-CoA reductases/métabolisme , Proteasome endopeptidase complex/métabolisme , Noyau de la cellule/métabolisme , Régions promotrices (génétique)/génétique , Cellules HepG2 , Animaux , Protéolyse/effets des médicaments et des substances chimiquesRÉSUMÉ
BACKGROUND: Vitamin E ( -tocopherol) and cholesterol are crucial components in cellular protection and physiological processes. Their uses in biological media face challenges due to their poor solubility and stability. OBJECTIVE: The study investigated the complex interactions of these bioactive compounds in various encapsulation systems of cyclodextrin and liposome, as well as dispersion in PEG-6000, in an attempt to improve the viability, motility, and preservation of ovine sperm cells. MATERIALS AND METHODS: The work explored the in vitro dissolution kinetics of vitamin E (d-tocopherol) and cholesterol using semi-empirical models. RESULTS: The release profiles of VitE and Chl varied considerably, depending on the specific carrier systems. For liposome-loaded VitE and Chl, the Korsmeyer-Peppas model gave the best fit; for CD/VitE and CD/Chl, the Higuchi model provided the best fit, whereas for PEG-6000 dispersions (VitE and Chl) both the Higuchi and Korsmeyer-Peppas models demonstrated the excellent fit. All systems indicated a Fickian diffusion mechanism dictated by the concentration gradient. The delivery of VitE and Chl with CD, liposome and PEG dispersion significantly increased sperm mobility and motility. The effect on the VCL parameter was the greatest by liposome-loaded VitE and Chl, followed by CD encapsulation and PEG-6000 dispersion. CONCLUSION: The dynamics of vitamin E and cholesterol within innovative delivery systems offers valuable insights into the development of advanced solutions in reproductive health, particularly on improving the viability, motility of refrigerated ovine sperm cells. Doi.org/10.54680/fr24510110712.
Sujet(s)
Cholestérol , Liposomes , Conservation de semence , Mobilité des spermatozoïdes , Spermatozoïdes , Vitamine E , Animaux , Mâle , Vitamine E/composition chimique , Cholestérol/composition chimique , Cholestérol/métabolisme , Ovis , Conservation de semence/méthodes , Conservation de semence/médecine vétérinaire , Spermatozoïdes/effets des médicaments et des substances chimiques , Spermatozoïdes/physiologie , Mobilité des spermatozoïdes/effets des médicaments et des substances chimiques , Liposomes/composition chimique , Cyclodextrines/composition chimique , Polyéthylène glycols/composition chimique , Solubilité , Survie cellulaire/effets des médicaments et des substances chimiques , Cryoconservation/méthodesRÉSUMÉ
Stress-induced alterations in central neuron metabolism and function are crucial contributors to depression onset. However, the metabolic dysfunctions of the neurons associated with depression and specific molecular mechanisms remain unclear. This study initially analyzed the relationship between cholesterol and depression using the NHANES database. We then induced depressive-like behaviors in mice via restraint stress. Applying bioinformatics, pathology, and molecular biology, we observed the pathological characteristics of brain cholesterol homeostasis and investigated the regulatory mechanisms of brain cholesterol metabolism disorders. Through the NHANES database, we initially confirmed a significant correlation between cholesterol metabolism abnormalities and depression. Furthermore, based on successful stress mouse model establishment, we discovered the number of cholesterol-related DEGs significantly increased in the brain due to stress, and exhibited regional heterogeneity. Further investigation of the frontal cortex, a brain region closely related to depression, revealed stress caused significant disruption to key genes related to cholesterol metabolism, including HMGCR, CYP46A1, ACAT1, APOE, ABCA1, and LDLR, leading to an increase in total cholesterol content and a significant decrease in synaptic proteins PSD-95 and SYN. This indicates cholesterol metabolism affects neuronal synaptic plasticity and is associated with stress-induced depressive-like behavior in mice. Adeno-associated virus interference with NR3C1 in the prefrontal cortex of mice subjected to short-term stress resulted in reduced protein levels of NRIP1, NR1H2, ABCA1, and total cholesterol content. At the same time, it increased synaptic proteins PSD95 and SYN, effectively alleviating depressive-like behavior. Therefore, these results suggest that short-term stress may induce cholesterol metabolism disorders by activating the NR3C1/NRIP1/NR1H2 signaling pathway. This impairs neuronal synaptic plasticity and consequently participates in depressive-like behavior in mice. These findings suggest that abnormal cholesterol metabolism in the brain induced by stress is a significant contributor to depression onset.
Sujet(s)
Cholestérol , Dépression , Lobe frontal , Stress psychologique , Animaux , Souris , Cholestérol/métabolisme , Dépression/métabolisme , Dépression/étiologie , Stress psychologique/métabolisme , Lobe frontal/métabolisme , Mâle , Modèles animaux de maladie humaine , Souris de lignée C57BL , Métabolisme lipidiqueSujet(s)
Cholestérol , Récepteurs hépatiques X , État prédiabétique , Transduction du signal , Humains , État prédiabétique/métabolisme , Récepteurs hépatiques X/métabolisme , Récepteurs hépatiques X/génétique , Cholestérol/métabolisme , Récepteurs cytoplasmiques et nucléaires/métabolisme , Récepteurs cytoplasmiques et nucléaires/génétique , Animaux , Diabète/métabolisme , Facteurs de risque , Diabète de type 2/métabolisme , SourisSujet(s)
Membre-1 de la sous-famille G des transporteurs à cassette liant l'ATP , Cholestérol , Cholestérol/métabolisme , Cholestérol/biosynthèse , Animaux , Membre-1 de la sous-famille G des transporteurs à cassette liant l'ATP/métabolisme , Membre-1 de la sous-famille G des transporteurs à cassette liant l'ATP/génétique , Humains , Glandes surrénales/métabolisme , Stéroïdes/biosynthèse , Stéroïdes/métabolisme , SourisRÉSUMÉ
Progressive Rod-Cone Degeneration (PRCD) is an integral membrane protein found in photoreceptor outer segment (OS) disc membranes and its function remains unknown. Mutations in Prcd are implicated in Retinitis pigmentosa (RP) in humans and multiple dog breeds. PRCD-deficient models exhibit decreased levels of cholesterol in the plasma. However, potential changes in the retinal cholesterol remain unexplored. In addition, impaired phagocytosis observed in these animal models points to potential deficits in the retinal pigment epithelium (RPE). Here, using a Prcd-/- murine model we investigated the alterations in the retinal cholesterol levels and impairments in the structural and functional integrity of the RPE. Lipidomic and immunohistochemical analyses show a 5-fold increase in the levels of cholesteryl esters (C.Es) and lipid deposits in the PRCD-deficient retina, respectively, indicating alterations in total retinal cholesterol. Furthermore, the RPE of Prcd-/- mice exhibit a 1.7-fold increase in the expression of lipid transporter gene ATP-binding cassette transporter A1 (Abca1). Longitudinal fundus and spectral domain optical coherence tomography (SD-OCT) examinations showed focal lesions and RPE hyperreflectivity. Strikingly, the RPE of Prcd-/- mice exhibited age-related pathological features such as lipofuscin accumulation, Bruch's membrane (BrM) deposits and drusenoid focal deposits, mirroring an Age-related Macular Degeneration (AMD)-like phenotype. We propose that the extensive lipofuscin accumulation likely impairs lysosomal function, leading to the defective phagocytosis observed in Prcd-/- mice. Our findings support the dysregulation of retinal cholesterol homeostasis in the absence of PRCD. Further, we demonstrate that progressive photoreceptor degeneration in Prcd-/- mice is accompanied by progressive structural and functional deficits in the RPE, which likely exacerbates vision loss over time.
Sujet(s)
Modèles animaux de maladie humaine , Épithélium pigmentaire de la rétine , Tomographie par cohérence optique , Animaux , Épithélium pigmentaire de la rétine/métabolisme , Épithélium pigmentaire de la rétine/anatomopathologie , Souris , Métabolisme lipidique , Souris knockout , Souris de lignée C57BL , Membre-1 de la sous-famille A des transporteurs à cassette liant l'ATP/génétique , Membre-1 de la sous-famille A des transporteurs à cassette liant l'ATP/métabolisme , Cholestérol/métabolisme , Cholestérol ester/métabolisme , Dystrophies des cônes et des batonnets/métabolisme , Dystrophies des cônes et des batonnets/génétique , Électrorétinographie , Membrane de Brüch/métabolisme , Membrane de Brüch/anatomopathologie , Immunohistochimie , Dégénérescence maculaire/congénitalRÉSUMÉ
PURPOSE: Cholesterol metabolism reprograming has been acknowledged as a novel feature of cancers. Pancreatic ductal adenocarcinoma (PDAC) is a cancer with a high demand of cholesterol for rapid growth. The underlying mechanism of how cholesterol metabolism homestasis are disturbed in PDAC is explored. EXPERIMENTAL DESIGN: The relevance between PDAC and cholesterol was confirmed in TCGA database. The expression and clinical association were discovered in TCGA and GEO datasets. Knockdown and overexpression of AGFG1 was adopted to perform function studies. RNA sequencing, cholesterol detection, transmission electron microscope, co-immunoprecipitation, and immunofluorescence et al. were utilized to reveal the underlying mechanism. RESULTS: AGFG1 was identified as one gene positively correlated with cholesterol metabolism in PDAC as revealed by bioinformatics analysis. AGFG1 expression was then found associated with poor prognosis in PDAC. AGFG1 knockdown led to decreased proliferation of tumor cells both in vitro and in vivo. By RNA sequencing, we found AGFG1 upregulated expression leads to enhanced intracellular cholesterol biosynthesis. AGFG1 knockdown suppressed cholesterol biosynthesis and an accumulation of cholesterol in the ER. Mechanistically, we confirmed that AGFG1 interacted with CAV1 to relocate cholesterol for the proceeding of cholesterol biosynthesis, therefore causing disorders in intracellular cholesterol metabolism. CONCLUSIONS: Our study demonstrates the tumor-promoting role of AGFG1 by disturbing cholesterol metabolism homestasis in PDAC. Our study has present a new perspective on cancer therapeutic approach based on cholerstrol metabolism in PDAC.
Sujet(s)
Carcinome du canal pancréatique , Prolifération cellulaire , Cholestérol , Homéostasie , Tumeurs du pancréas , Humains , Cholestérol/métabolisme , Cholestérol/biosynthèse , Carcinome du canal pancréatique/anatomopathologie , Carcinome du canal pancréatique/métabolisme , Carcinome du canal pancréatique/génétique , Tumeurs du pancréas/anatomopathologie , Tumeurs du pancréas/métabolisme , Tumeurs du pancréas/génétique , Animaux , Lignée cellulaire tumorale , Souris , Régulation de l'expression des gènes tumoraux , Évolution de la maladie , Pronostic , Cavéoline-1/génétique , Cavéoline-1/métabolisme , Souris nude , MâleRÉSUMÉ
BACKGROUND: Previous epidemiological studies have repeatedly found per- and polyfluoroalkyl substances (PFAS) exposure associated with higher circulating cholesterol, one of the greatest risk factors for development of coronary artery disease. The main route of cholesterol catabolism is through its conversion to bile acids, which circulate between the liver and ileum via enterohepatic circulation. Patients with coronary artery disease have decreased bile acid excretion, indicating that PFAS-induced impacts on enterohepatic circulation may play a critical role in cardiovascular risk. OBJECTIVES: Using a mouse model with high levels of low-density and very low-density lipoprotein (LDL and VLDL, respectively) cholesterol and aortic lesion development similar to humans, the present study investigated mechanisms linking exposure to a PFAS mixture with increased cholesterol. METHODS: Male and female Ldlr-/- mice were fed an atherogenic diet (Clinton/Cybulsky low fat, 0.15% cholesterol) and exposed to a mixture of 5 PFAS representing legacy, replacement, and emerging subtypes (i.e., PFOA, PFOS, PFHxS, PFNA, GenX), each at a concentration of 2mg/L, for 7 wk. Blood was collected longitudinally for cholesterol measurements, and mass spectrometry was used to measure circulating and fecal bile acids. Transcriptomic analysis of ileal samples was performed via RNA sequencing. RESULTS: After 7 wk of PFAS exposure, average circulating PFAS levels were measured at 21.6, 20.1, 31.2, 23.5, and 1.5µg/mL in PFAS-exposed females and 12.9, 9.7, 23, 14.3, and 1.7µg/mL in PFAS-exposed males for PFOA, PFOS, PFHxS, PFNA, and GenX, respectively. Total circulating cholesterol levels were higher in PFAS-exposed mice after 7 wk (352mg/dL vs. 415mg/dL in female mice and 392mg/dL vs. 488mg/dL in male mice exposed to vehicle or PFAS, respectively). Total circulating bile acid levels were higher in PFAS-exposed mice (2,978 pg/µL vs. 8,496 pg/µL in female mice and 1,960 pg/µL vs. 4,452 pg/µL in male mice exposed to vehicle or PFAS, respectively). In addition, total fecal bile acid levels were lower in PFAS-exposed mice (1,797 ng/mg vs. 682 ng/mg in females and 1,622 ng/mg vs. 670 ng/mg in males exposed to vehicle or PFAS, respectively). In the ileum, expression levels of the apical sodium-dependent bile acid transporter (ASBT) were higher in PFAS-exposed mice. DISCUSSION: Mice exposed to a PFAS mixture displayed higher circulating cholesterol and bile acids perhaps due to impacts on enterohepatic circulation. This study implicates PFAS-mediated effects at the site of the ileum as a possible critical mediator of increased cardiovascular risk following PFAS exposure. https://doi.org/10.1289/EHP14339.
Sujet(s)
Acides et sels biliaires , Fluorocarbones , Animaux , Acides et sels biliaires/métabolisme , Souris , Fluorocarbones/toxicité , Mâle , Femelle , Récepteurs aux lipoprotéines LDL/génétique , Récepteurs aux lipoprotéines LDL/métabolisme , Polluants environnementaux/toxicité , Lipides/sang , Cholestérol/sang , Cholestérol/métabolisme , Acides alcanesulfoniques/toxicitéRÉSUMÉ
Purpose: Dysregulated cholesterol metabolism is critical in the pathogenesis of AMD. Cellular senescence contributes to the development of numerous age-associated diseases. In this study, we investigated the link between cholesterol burden and the cellular senescence of photoreceptors. Methods: Retinas from rod-specific ATP binding cassette subfamily A member 1 (Abca1) and G member 1 (Abcg1) (Abca1/g1-rod/-rod) knockout mice fed with a high-fat diet were analyzed for the signs of cellular senescence. Real-time quantitative PCR and immunofluorescence were used to characterize the senescence profile of the retina and cholesterol-treated photoreceptor cell line (661W). Inducible elimination of p16(Ink4a)-positive senescent cells (INK-ATTAC) mice or the administration of senolytic drugs (dasatinib and quercetin: D&Q) were used to examine the impact of senolytics on AMD-like phenotypes in Abca1/g1-rod/-rod retina. Results: Increased accumulation of senescent cells as measured by markers of cellular senescence was found in Abca1/g1-rod/-rod retina. Exogenous cholesterol also induced cellular senescence in 661W cells. Selective elimination of senescent cells in Abca1/g1-rod/-rod;INK-ATTAC mice or by administration of D&Q improved visual function, lipid accumulation in retinal pigment epithelium, and Bruch's membrane thickening. Conclusions: Cholesterol accumulation promotes cellular senescence in photoreceptors. Eliminating senescent photoreceptors improves visual function in a model of retinal neurodegeneration, and senotherapy offers a novel therapeutic avenue for further investigation.
Sujet(s)
Membre-1 de la sous-famille A des transporteurs à cassette liant l'ATP , Vieillissement de la cellule , Cholestérol , Modèles animaux de maladie humaine , Souris knockout , Dégénérescence de la rétine , Animaux , Souris , Vieillissement de la cellule/physiologie , Cholestérol/métabolisme , Membre-1 de la sous-famille A des transporteurs à cassette liant l'ATP/métabolisme , Dégénérescence de la rétine/métabolisme , Dégénérescence de la rétine/anatomopathologie , Réaction de polymérisation en chaine en temps réel , Souris de lignée C57BL , Membre-1 de la sous-famille G des transporteurs à cassette liant l'ATP/métabolisme , Membre-1 de la sous-famille G des transporteurs à cassette liant l'ATP/génétique , Cellules photoréceptrices en bâtonnet de la rétine/métabolisme , Cellules photoréceptrices en bâtonnet de la rétine/anatomopathologie , Cellules photoréceptrices en bâtonnet de la rétine/physiologieRÉSUMÉ
Maternal high-fat diet intake has profound effects on the long-term health of offspring, predisposing them to a higher susceptibility to obesity and metabolic dysfunction-associated steatotic liver disease. However, the detailed mechanisms underlying the role of a maternal high-fat diet in hepatic lipid accumulation in offspring, especially at the weaning age, remain largely unclear. In this study, female C57BL/6J mice were randomly assigned to either a high-fat diet or a control diet, and lipid metabolism parameters were assessed in male offspring at weaning. Gut microbiota analysis and targeted metabolomics of short-chain fatty acids (SCFAs) in these offspring were further performed. Both in vivo and in vitro studies were conducted to explore the role of butyrate in hepatic cholesterol excretion in the liver and HepG2 cells. Our results showed that maternal high-fat feeding led to obesity and dyslipidemia, and exacerbated hepatic lipid accumulation in the livers of offspring at weaning. We observed significant decreases in the abundance of the Firmicutes phylum and the Allobaculum genus, known as producers of SCFAs, particularly butyrate, in the offspring of dams fed a high-fat diet. Additionally, maternal high-fat diet feeding markedly decreased serum butyrate levels and down-regulated ATP-binding cassette transporters G5 (ABCG5) in the liver, accompanied by decreased phosphorylated AMP-activated protein kinase (AMPK) and histone deacetylase 5 (HADC5) expressions. Subsequent in vitro studies revealed that butyrate could induce ABCG5 activation and alleviate lipid accumulation via the AMPK-pHDAC5 pathway in HepG2 cells. Moreover, knockdown of HDAC5 up-regulated ABCG5 expression and promoted cholesterol excretion in HepG2 cells. In conclusion, our study provides novel insights into how maternal high-fat diet feeding inhibits hepatic cholesterol excretion and down-regulates ABCG5 through the butyrate-AMPK-pHDAC5 pathway in offspring at weaning.
Sujet(s)
Membre-5 de la sous-famille G des transporteurs à cassette liant l'ATP , Butyrates , Cholestérol , Alimentation riche en graisse , Microbiome gastro-intestinal , Foie , Souris de lignée C57BL , Animaux , Alimentation riche en graisse/effets indésirables , Femelle , Butyrates/métabolisme , Humains , Foie/métabolisme , Cellules HepG2 , Membre-5 de la sous-famille G des transporteurs à cassette liant l'ATP/métabolisme , Membre-5 de la sous-famille G des transporteurs à cassette liant l'ATP/génétique , Mâle , Cholestérol/métabolisme , Cholestérol/sang , Grossesse , Souris , Métabolisme lipidique , Effets différés de l'exposition prénatale à des facteurs de risque/métabolisme , Phénomènes physiologiques nutritionnels maternels , Obésité/métabolisme , Obésité/microbiologie , Dyslipidémies/métabolisme , Dyslipidémies/microbiologie , Dyslipidémies/étiologie , LipoprotéinesRÉSUMÉ
Cholesterol and Helicobacter pylori (H. pylori) are both risk factors for gastric cancer (GC). However, the relationship between cholesterol and H. pylori and their function in the progression of GC are controversial. In this study, we addressed that H. pylori could induce mitochondrial cholesterol accumulation and promote GC proliferation and protect GC cells against apoptosis via cholesterol. Metabolomic and transcriptomic sequencing were used to identify CYP11A1 responsible for H. pylori-induced cholesterol accumulation. In vitro and in vivo function experiments revealed that cholesterol could promote the proliferation of GC and inhibit apoptosis. Mechanically, the interaction of Cytotoxin-associated gene A (CagA) and CYP11A1 redistributed mitochondrial CYP11A1 outside the mitochondria and subsequently caused mitochondrial cholesterol accumulation. The CYP11A1-knockdown upregulated cholesterol accumulation and reproduced the effect of cholesterol on GC in a cholesterol-dependent manner. Moreover, CYP11A1-knockdown or H. pylori infection inhibited mitophagy and maintained the mitochondria homeostasis. H. pylori could contribute to the progression of GC through the CagA/CYP11A1-mitoCHO axis. This study demonstrates that H. pylori can contribute to the progression of GC via cholesterol, and eradicating H. pylori is still prognostically beneficial to GC patients.
Sujet(s)
Cholestérol , Helicobacter pylori , Mitochondries , Tumeurs de l'estomac , Helicobacter pylori/métabolisme , Tumeurs de l'estomac/microbiologie , Tumeurs de l'estomac/métabolisme , Tumeurs de l'estomac/anatomopathologie , Cholestérol/métabolisme , Humains , Mitochondries/métabolisme , Cholesterol side-chain cleavage enzyme/métabolisme , Cholesterol side-chain cleavage enzyme/génétique , Infections à Helicobacter/métabolisme , Infections à Helicobacter/microbiologie , Animaux , Antigènes bactériens/métabolisme , Antigènes bactériens/génétique , Protéines bactériennes/métabolisme , Protéines bactériennes/génétique , Lignée cellulaire tumorale , Souris , Apoptose , Mâle , Prolifération cellulaireRÉSUMÉ
Syrian hamsters are valuable models for studying lipid metabolism due to their sensitivity to dietary cholesterol, yet the precise impact of varying cholesterol levels has not been comprehensively assessed. This study examined the impact of varying dietary cholesterol levels on lipid metabolism in Syrian hamsters. Diets ranging from 0% to 1% cholesterol were administered to assess lipid profiles and oxidative stress markers. Key findings indicate specific cholesterol thresholds for inducing distinct lipid profiles: below 0.13% for normal lipids, 0.97% for elevated LDL-C, 0.43% for increased VLDL-C, and above 0.85% for heightened hepatic lipid accumulation. A cholesterol supplementation of 0.43% induced hypercholesterolemia without adverse liver effects or abnormal lipoprotein expression. Furthermore, cholesterol supplementation significantly increased liver weight, plasma total cholesterol, LDL-C, and VLDL-C levels while reducing the HDL-C/LDL-C ratio. Fecal cholesterol excretion increased, with stable bile acid levels. High cholesterol diets correlated with elevated plasma ALT activities, reduced hepatic lipid peroxidation, and altered leptin and CETP levels. These findings underscore Syrian hamsters as robust models for hyperlipidemia research, offering insights into experimental methodologies. The identified cholesterol thresholds facilitate precise lipid profile manipulation, enhancing the hamster's utility in lipid metabolism studies and potentially informing clinical approaches to managing lipid disorders.
Sujet(s)
Cholestérol alimentaire , Métabolisme lipidique , Foie , Mesocricetus , Animaux , Cholestérol alimentaire/administration et posologie , Foie/métabolisme , Mâle , Cricetinae , Fèces/composition chimique , Stress oxydatif , Hypercholestérolémie/métabolisme , Hypercholestérolémie/sang , Cholestérol LDL/sang , Peroxydation lipidique , Cholestérol/sang , Cholestérol/métabolisme , Acides et sels biliaires/métabolisme , Leptine/sang , Leptine/métabolisme , Protéines de transfert des esters de cholestérol/métabolismeRÉSUMÉ
We aimed to characterize the anti-obesity and anti-atherosclerosis effects of Lactobacillus curvatus HY7601 and Lactobacillus plantarum KY1032 using high-fat diet (HFD)-fed obese C57BL/6 mice. We divided the mice into control (CON), HFD, HFD with 108 CFU/kg/day probiotics (HFD + KL, HY7301:KY1032 = 1:1), and HFD with 109 CFU/kg/day probiotics (HFD + KH, HY7301:KY1032 = 1:1) groups and fed/treated them during 7 weeks. The body mass, brown adipose tissue (BAT), inguinal white adipose tissue (iWAT), and epididymal white adipose tissue (eWAT) masses and the total cholesterol and triglyceride concentrations were remarkably lower in probiotic-treated groups than in the HFD group in a dose-dependent manner. In addition, the expression of uncoupling protein 1 in the BAT, iWAT, and eWAT was significantly higher in probiotic-treated HFD mice than in the HFD mice, as demonstrated by immunofluorescence staining and Western blotting. We also measured the expression of cholesterol transport genes in the liver and jejunum and found that the expression of those encoding liver-X-receptor α, ATP-binding cassette transporters G5 and G8, and cholesterol 7α-hydroxylase were significantly higher in the HFD + KH mice than in the HFD mice. Thus, a Lactobacillus HY7601 and KY1032 mixture with 109 CFU/kg/day concentration can assist with body weight regulation through the management of lipid metabolism and thermogenesis.
Sujet(s)
Cholestérol , Alimentation riche en graisse , Métabolisme énergétique , Lactobacillus , Souris de lignée C57BL , Probiotiques , Animaux , Alimentation riche en graisse/effets indésirables , Probiotiques/pharmacologie , Probiotiques/administration et posologie , Cholestérol/métabolisme , Cholestérol/sang , Métabolisme énergétique/effets des médicaments et des substances chimiques , Mâle , Souris , Tissu adipeux brun/métabolisme , Tissu adipeux brun/effets des médicaments et des substances chimiques , Obésité/métabolisme , Obésité/microbiologie , Tissu adipeux blanc/métabolisme , Protéine-1 de découplage/métabolisme , Protéine-1 de découplage/génétique , Tissu adipeux/métabolisme , Foie/métabolisme , Lactobacillus plantarum , Jéjunum/métabolisme , Jéjunum/effets des médicaments et des substances chimiques , Jéjunum/microbiologieRÉSUMÉ
Sphingomyelin is postulated to form clusters with glycosphingolipids, cholesterol and other sphingomyelin molecules in biomembranes through hydrophobic interaction and hydrogen bonds. These clusters form submicron size lipid domains. Proteins that selectively binds sphingomyelin and/or cholesterol are useful to visualize the lipid domains. Due to their small size, visualization of lipid domains requires advanced microscopy techniques in addition to lipid binding proteins. This Chapter describes the method to characterize plasma membrane sphingomyelin-rich and cholesterol-rich lipid domains by quantitative microscopy. This Chapter also compares different permeabilization methods to visualize intracellular lipid domains.
Sujet(s)
Cholestérol , Sphingomyéline , Sphingomyéline/composition chimique , Sphingomyéline/métabolisme , Cholestérol/composition chimique , Cholestérol/métabolisme , Humains , Animaux , Microdomaines membranaires/métabolisme , Microdomaines membranaires/composition chimique , Microscopie/méthodes , Protéines de transport/composition chimique , Protéines de transport/métabolisme , Membrane cellulaire/métabolisme , Membrane cellulaire/composition chimiqueRÉSUMÉ
Synthetic model membranes are important tools to elucidate lipid domain and protein interactions due to predefined lipid compositions and characterizable biophysical properties. Here, we introduce a model membrane with multiple lipid bilayers (multi-bilayers) stacked on a mica substrate that is prepared through a spin-coating technique. The spin-coated multi-bilayers are useful in the study of phase separated membranes with a high cholesterol content, mobile lipids, microscopic and reversible phase separation, and easy conjugation with proteins, which make them a good model to study interactions between proteins and membrane domains.
Sujet(s)
Double couche lipidique , Double couche lipidique/composition chimique , Double couche lipidique/métabolisme , Protéines membranaires/composition chimique , Protéines membranaires/métabolisme , Cholestérol/composition chimique , Cholestérol/métabolisme , Silicates d'aluminium/composition chimique , Microdomaines membranaires/composition chimique , Microdomaines membranaires/métabolisme , Liaison aux protéinesRÉSUMÉ
Lipids are compounds involved in many biologic functions including cell structure, metabolism, energy storage and are involved in signaling. A prominent lipid in these functions is cholesterol. Cholesterol also plays a part in the signaling of melanocytes, which contain melanosomes. The maturation of these melanosomes happens during melanocyte growth. The deficit of melanogenesis or melanosome maturation is associated with ocular albinism in the eye. Aberrations of melanosome maturation are also associated with pigment dispersion syndrome. Albinism and pigment dispersion manifestations are systemic. Both melanogenesis and melanocyte maturation are affected by cholesterol metabolism. Cholesterol signaling is a part of many pathways in the body, and evaluating these signals can have implications in systemic disease processes of melanogenesis and melanosome maturation, like ocular albinism and pigment dispersion. Cholesterol is carried by lipoprotein particles. Low-density lipoprotein (LDL) is usually the transport vehicle for cholesterol to reach tissues and organelles. The LDL uptake on cells often sends out a cascade of internal signaling within the cells. We describe here LDL signaling related to lipase activity changes using enzymatic methods with a kit. We describe analyses of cholesterol esters and free cholesterol with liquid chromatography and gas chromatography with or in tandem with mass spectrometry (GC-MS and LC-MS/MS). These analyses will provide insight into melanosome maturation and melanogenesis. The methods described here are applicable to all melanocytes within the body of a model mammalian organism.
Sujet(s)
Cholestérol , Iris , Mélanocytes , Transduction du signal , Mélanocytes/métabolisme , Humains , Cholestérol/métabolisme , Iris/métabolisme , Lipoprotéines/métabolisme , Mélanosomes/métabolisme , Lipoprotéines LDL/métabolisme , Spectrométrie de masse en tandem/méthodes , Chromatographie gazeuse-spectrométrie de masse/méthodes , Chromatographie en phase liquide/méthodes , Triacylglycerol lipase/métabolisme , Mélanines/métabolisme , Cholestérol ester/métabolismeRÉSUMÉ
Fully targeted mRNA therapeutics necessitate simultaneous organ-specific accumulation and effective translation. Despite some progress, delivery systems are still unable to fully achieve this. Here, we reformulate lipid nanoparticles (LNPs) through adjustments in lipid material structures and compositions to systematically achieve the pulmonary and hepatic (respectively) targeted mRNA distribution and expression. A combinatorial library of degradable-core based ionizable cationic lipids is designed, following by optimisation of LNP compositions. Contrary to current LNP paradigms, our findings demonstrate that cholesterol and phospholipid are dispensable for LNP functionality. Specifically, cholesterol-removal addresses the persistent challenge of preventing nanoparticle accumulation in hepatic tissues. By modulating and simplifying intrinsic LNP components, concurrent mRNA accumulation and translation is achieved in the lung and liver, respectively. This targeting strategy is applicable to existing LNP systems with potential to expand the progress of precise mRNA therapy for diverse diseases.