LDLR Expression Research Articles

A molecular and immunohistochemical study of 37 cases of ovarian Sertoli-Leydig cell tumor.

This study provides an analysis of 37 ovarian Sertoli-Leydig cell tumors (SLCT), focusing on their morphological, immunohistochemical, and molecular features. The cohort was comprised of 9 well-differentiated, 25 moderately differentiated, and 3 poorly differentiated tumors. The immunohistochemical analysis was performed with 28 markers, including diagnostic markers and markers with possible predictive significance. The results showed high expression of sex cord markers (FOXL2, SF1, inhibin A, CD99, calretinin, ER, PR, AR), and variable expression of other markers such as CKAE1/3 (83%), CAIX (14%), and MUC4 (1%). Loss of PTEN expression was present in 14% of cases, and CTLA4 expression was seen in 43% of cases. All tumors were MMR proficient and HER2 and PD-L1 negative. The molecular analysis showed DICER1 mutations in 54.5% of cases, and a FOXL2 mutation in 6% of tumors. In addition, we detected 2 cases with TERT promoter mutation. RNA NGS sequencing identified significant differences in mRNA expression between DICER1MUT and DICER1WT tumors. The DICER1WT tumors showed increased expression of PRKCA, HNF1A, LDLR, and MAP2K5. On the contrary, the DICER1MUT cases showed increased expression of CDK6, NOTCH2, and FGFR2. The results of our study show that SLCTs exhibit distinct molecular features based on their degree of differentiation. We have confirmed that DICER1 mutations are characteristic of moderately and poorly differentiated SLCTs, while well-differentiated SLCTs may represent a distinct entity. DICER1MUT and DICER1WT tumors showed different mRNA expression profiles. The FOXL2 mutation is less common in these tumors and is mutually exclusive with the DICER1 mutation.

TOMM40 regulates hepatocellular and plasma lipid metabolism via an LXR-dependent pathway

ObjectiveThe gene encoding TOMM40 (Transporter of Outer Mitochondrial Membrane 40) is adjacent to that encoding APOE, which has a central role in lipid and lipoprotein metabolism. While human genetic variants near APOE and TOMM40 have been shown to be strongly associated with plasma lipid levels, a specific role for TOMM40 in lipid metabolism has not been established, and the present study was aimed at assessing this possibility. MethodsTOMM40 was knocked down by siRNA in human hepatoma HepG2 cells, and effects on mitochondrial function, lipid phenotypes, and crosstalk between mitochondria, ER, and lipid droplets were examined. Additionally, hepatic and plasma lipid levels were measured in mice following shRNA-induced knockdown of Tomm40 shRNA. ResultsIn HepG2 cells, TOMM40 knockdown upregulated expression of APOE and LDLR in part via activation of LXRB (NR1H2) by oxysterols, with consequent increased uptake of VLDL and LDL. This is in part due to disruption of mitochondria-endoplasmic reticulum contact sites, with resulting accrual of reactive oxygen species and non-enzymatically derived oxysterols. With TOMM40 knockdown, cellular triglyceride and lipid droplet content were increased, effects attributable in part to receptor-mediated VLDL uptake, since lipid staining was significantly reduced by concomitant suppression of either LDLR or APOE. In contrast, cellular cholesterol content was reduced due to LXRB-mediated upregulation of the ABCA1 transporter as well as increased production and secretion of oxysterol-derived cholic acid. Consistent with the findings in hepatoma cells, in vivo knockdown of TOMM40 in mice resulted in significant reductions of plasma triglyceride and cholesterol concentrations, reduced hepatic cholesterol and increased triglyceride content, and accumulation of lipid droplets leading to development of steatosis. ConclusionsThese findings demonstrate a role for TOMM40 in regulating hepatic lipid and plasma lipoprotein levels and identify mechanisms linking mitochondrial function with lipid metabolism.

Fluorescent gold nanoclusters possess multiple actions against atherosclerosis

Atherosclerosis caused major morbidity and mortality worldwide. Molecules possessing lipid-lowering and/or anti-inflammatory properties are potential druggable targets against atherosclerosis. We examined the anti-atherosclerotic effects of fluorescent gold nanoclusters (FANC), which were dihydrolipoic acid (DHLA)-capped 2-nm gold nanoparticles. We evaluated the 8-week effects of FANC in Western-type diet-fed ApoE-deficient mice by either continuous intraperitoneal delivery (20 μM, 50 μl weekly) or via drinking water (300 nM). FANC reduced aortic atheroma burden, serum total cholesterol, and oxidative stress markers malondialdehyde and 4-hydroxynonenal levels. FANC attenuated hepatic lipid deposit, with changed expression of lipid homeostasis-related genes HMGCR, SREBP, PCSK9, and LDLR in a pattern similar to mice treated with ezetimibe. FANC also inhibited intestinal cholesterol absorption, resembling the action of ezetimibe. The lipid-lowering and anti-atherosclerotic effects of FANC reappeared in Western-type diet-fed LDLr-deficient mice. FANC bound insulin receptor β (IRβ) via DHLA, leading to AKT activation. However, unlike insulin, which also bound IRβ to activate AKT to induce HO-1, activation of AKT by FANC was independent of HO-1 expression in human aortic endothelial cells (HAECs). Alternatively, FANC up-regulated NRF2, interfered the binding of KEAP1 to NRF2, and promoted KEAP1 degradation to free NRF2 for nuclear entry to induce HO-1 that suppressed the expression of ICAM-1 and VCAM-1. Consistently, FANC suppressed ox-LDL-induced enhanced attachment of THP-derived macrophages onto HAECs. In macrophages, FANC up-regulated ABCA1, and reversed ox-LDL-induced suppression of cholesterol efflux. FANC effected in vitro at nano moles. In conclusion, our findings showed novel actions and multiple mechanisms of FANC worked coherently against atherosclerosis.

Dihydrotanshinone I promotes LDL uptake by HepG2 cells through increasing LDLR level

ABSTRACT Dihydrotanshinone I (DHT), a lipophilic compound extracted from Salvia miltiorrhiza, has cardiovascular protective effects, but the underlying molecular mechanisms of action have rarely been reported. Based on this, whether DHT affects cholesterol metabolism by regulating LDLR is investigated in this work. The results revealed that DHT can increase LDLR expression and promote LDL uptake by HepG2 cells. Meanwhile, DHT stabilizes LDLR mRNA expression by activating the epidermal growth factor receptor/extracellular signal-regulated kinase 1/2 (EGFR/erk1/2) signaling pathway. In addition, DHT inhibits the expression of the proprotein convertase subtilisin/kexin type 9 (PCSK9) by down-regulating the liver nuclear transcription factor 1 A (HNF1A) and up-regulating the forkhead box O3 (FOXO3). All of these indicate that DHT increases LDLR expression at the post-transcriptional and post-translational levels thereby promoting LDL-C metabolism. The potential mechanism of DHT to improve lipid metabolism has been revealed as a promising drug against AS.

Novel Guanidinium-Functionalized Stigmasterol for Bile Salt Binding and Serum Cholesterol Reduction: Synthesis, Interaction Mechanisms, and In Vivo Function.

A novel amphiphilic guanidyl-functionalized stigmasterol hydrochloride (GFSH) was designed and synthesized as bile salt sequestrants for cholesterol reduction. GFSH exhibited a considerable in vitro capacity for bile salt binding in gastrointestinal digestion and alleviated hypercholesterolemia in vivo. GFSH spontaneously interacted with sodium cholate via synergistic electrostatic, hydrophobic, and hydrogen-bonding interactions. The effects of GFSH on serum cholesterol reduction in mice fed a high-fat-high-cholesterol diet were explored by measuring the expression of key transcription factors related to bile acid metabolism. GFSH produced a dose-dependent reduction in weight gain, hepatic fat accumulation, and fecal and blood markers. Real-time quantitative polymerase chain reaction (RT-qPCR) and western blot analyses demonstrated GFSH-induced expression of hepatic CYP7A, LXRα, and LDL-R. GFSH exerts the cholesterol-lowering activity by inducing the bile acid metabolism.

Organosulfur Compounds, S-Allyl-L-Cysteine and S-Ethyl-L-Cysteine, Target PCSK-9/LDL-R-Axis to Ameliorate Cardiovascular, Hepatic, and Metabolic Changes in High Carbohydrate and High Fat Diet-Induced Metabolic Syndrome in Rats.

Metabolic syndrome (MetS) is an ever-evolving set of diseases that poses a serious health risk in many countries worldwide. Existing evidence illustrates that individuals with MetS have a 30%-40% higher chance of acquiring type 2 diabetes mellitus (T2DM), cardiovascular disease (CVD), or both. This study was undertaken to uncover the regulatory role of natural organosulfur compounds (OSCs), S-allyl-L-cysteine (SAC), and S-ethyl-L-cysteine (SEC), in targeting high carbohydrate high fat (HCHF)-diet-induced MetS-associated risk management. Our findings suggested that SAC and SEC ameliorated HCHF-diet-induced diabetic profiles, plasma lipid and lipoprotein level, liver function, oxidative-stress, inflammatory cytokines, and chemokines including monocyte chemoattractant protein-1 (MCP-1), lipid peroxidation, plasma proprotein convertase subtilisin/kexin type-9 (PCSK-9), and high-sensitivity C-reactive protein (hs-CRP). Moreover, the assessment of the hepatic mRNA expression of the key genes involved in cholesterol homeostasis depicted that SAC and SEC downregulated the PCSK-9 mRNA expression via targeting the expression of HNF-1α, a transcriptional activator of PCSK-9. On the other hand, the LDL-receptor (LDL-R) expression was upregulated through the activation of its transcriptional regulator sterol regulatory element binding protein-2 (SREBP-2). In addition, the activity and the mRNA expression of 3-hydroxy-3-methylglutaryl coenzyme-A reductases (HMG-R) and peroxisome proliferator-activated receptors (PPARs) were also improved by the treatment of SAC and SEC. We concluded that SAC and SEC can protect against MetS via improving the lipid and lipoprotein content, glycemic indices, hepatic function, targeting the inflammatory cascades, and oxidative imbalance, regulation of the mRNA expression of PCSK-9, LDL-R, SREBP-2, HNF-1α, PPARs, and inflammatory biomarkers.

Quercetin represses cholesterol metabolism and mitigates resistance to cisplatin in oral squamous cell carcinoma by regulating AGR2/AKT/SREBP2 axis

PurposeThis study aimed to explore the effects of quercetin on cholesterol metabolism and cisplatin sensitivity in oral squamous cell carcinoma (OSCC) cell line (CAL27) and investigate the potential molecular mechanisms. MethodsCAL27 cells were exposed to quercetin or cisplatin after upregulation or downregulation of AGR2. The expression of proteins and genes associated with cholesterol metabolism were assessed. The levels of cholesterol and LDL were also measured, and the cisplatin sensitivity of CAL27 cells was analyzed. ResultsRNA high-throughput sequencing revealed that after treatment with quercetin, the expression of AGR2 was significantly reduced in cisplatin-resistant CAL27 cells (CAL-27R), which was associated with lipid metabolism. AGR2 deletion ameliorated but its overexpression exacerbated cisplatin resistance and cholesterol metabolism, evidenced by changes in SQLE, HMGCS, LDLR, and n-SREBP2 expression and cholesterol and LDL levels. Moreover, AGR2 promoted cisplatin resistance by activating the AKT signaling pathway and enhancing SREBP2-mediated cholesterol metabolism. Quercetin increased cisplatin sensitivity by repressing cholesterol metabolism but suppressed the AGR2/AKT/SREBP2 signaling pathway in a concentration-dependent manner. These effects were partly reversed by AGR2 overexpression and AKT activation. ConclusionOur findings demonstrated that quercetin inhibits cholesterol metabolism and cisplatin resistance in CAL27 cells by modulating the AGR2/AKT/SREBP2 axis.

25-Hydroxycholesterol attenuates tumor necrosis factor alpha-induced blood-brain barrier breakdown in vitro

Intracellular cholesterol metabolism is regulated by the SREBP-2 and LXR signaling pathways. The effects of inflammation on these molecular mechanisms remain poorly studied, especially at the blood-brain barrier (BBB) level. Tumor necrosis factor α (TNFα) is a proinflammatory cytokine associated with BBB dysfunction. Therefore, the aim of our study was to investigate the effects of TNFα on BBB cholesterol metabolism, focusing on its underlying signaling pathways. Using a human in vitro BBB model composed of human brain-like endothelial cells (hBLECs) and brain pericytes (HBPs), we observed that TNFα increases BBB permeability by degrading the tight junction protein CLAUDIN-5 and activating stress signaling pathways in both cell types. TNFα also promotes cholesterol release and decreases cholesterol accumulation and APOE secretion. In hBLECs, the expression of SREBP-2 targets (LDLR and HMGCR) is increased, while ABCA1 expression is decreased. In HBPs, only LDLR and ABCA1 expression is increased. TNFα treatment also induces 25-hydroxycholesterol (25-HC) production, a cholesterol metabolite involved in the immune response and intracellular cholesterol metabolism. 25-HC pretreatment attenuates TNFα-induced BBB leakage and partially alleviates the effects of TNFα on ABCA1, LDLR, and HMGCR expression. Overall, our results suggest that TNFα favors cholesterol efflux via an LXR/ABCA1-independent mechanism at the BBB, while it activates the SREBP-2 pathway. Treatment with 25-HC partially reversed the effect of TNFα on the LXR/SREBP-2 pathways. Our study provides novel perspectives for better understanding cerebrovascular signaling events linked to BBB dysfunction and cholesterol metabolism in neuroinflammatory diseases.

7-Ketocholesterol promotes cholesterol uptake and inflammation in macrophage: Potential mechanisms of dietary COP in atherosclerosis promotion

This study investigated the effects and mechanisms of 7-ketocholesterol in promoting macrophage foaming and inflammation. Single-cell RNA sequencing showed that dietary cholesterol oxidation products increased the inflammatory macrophage and Trem2high macrophage numbers in the atherosclerotic aorta of ApoE−/− mice. Enrichment analysis demonstrated activation of inflammation-related pathways (NF-κB pathway and NLRP3 inflammasome) in inflammatory macrophages and cholesterol metabolism-related pathways (LDLR and ABCG1) in Trem2high macrophages. An oxidized-LDL-treated macrophage model was employed to verify the effects and mechanisms of 7-KC on macrophage inflammation and foam cell formation. 7-KC promoted the inflammation and M1 polarization of macrophage in association with the activations of the NF-κB pathway and NLRP3 inflammasome. Furthermore, 7-KC-mediated excessive cholesterol accumulation was attributed to enhanced cholesterol uptake rather than inhibition of cholesterol efflux. Consequently, LDLR expression was up-regulated by 7-KC, while no significant effect on ABCG1 expression was observed.

DHA dietary intervention caused different hippocampal lipid and protein profile in ApoE-/- and C57BL/6J mice

BackgroundChanges in protein and lipid levels may occur in the Alzheimer’s disease brain, and DHA can have beneficial effects on it. To investigate the impact of DHA dietary intervention on brain protein and lipid profile in ApoE-/- mice and C57 mice. MethodThree-month-old ApoE-/- mice and C57 mice were randomly divided into two groups respectively, and fed with control diet and DHA-fortified diet for five months. Cortical TC, HDL-C and LDL-C levels and cholesterol metabolism-related protein expression were measured by ELISA or immunohistochemistry methods. Hippocampus were collected for proteomic and lipidomics analysis by LC-MS/MS and differential proteins and lipid metabolites were screened and further analyzed by GO functional annotation and KEGG pathway enrichment analysis. ResultsDHA intervention decreased cortical TC level in both C57 and ApoE-/- mice (P < 0.05), but caused different change of cortical HDL-C, LDL-C level and LDL-C/HDL-C ratio in C57 and ApoE-/- mice (P < 0.05). Discrepant cortical and hippocampal LDLR, ABCG1, Lox1 and SORT1 protein expression was found between C57 and ApoE-/- mice (P < 0.05), and DHA treatment caused different changes of these proteins in C57 and ApoE-/- mice (P < 0.05). Differential hippocampal proteins and lipids profile were found in C57 and ApoE-/- mice before and after DHA treatment, which were mainly involved in vesicular transport and phospholipid metabolic pathways. ConclusionApoE genetic defect caused abnormal cholesterol metabolism, and affected protein and lipid profile, as well as discrepant response of hippocampal protein and lipids profile in the brain of mice given DHA fortified diet intervention.

Postprandial changes to systemic metabolism imprint durable changes on T cell immune responses

Abstract Here we show short periods of fasting and refeeding can have long-lasting effects on T cell immunity. Mouse or human T cells from fed hosts have higher mitochondrial quality and respiratory capacity than those from fasted hosts ex vivo. These metabolic phenotypes persist after activation and expansion, both in vitro culture and in vivo in response to vaccination. Fed T cells outcompete fasted T cells in a co-transfer model, such that T cells from fasted hosts form far fewer memory T cells. Serum profiling revealed triglycerides as a driver of postprandial metabolic reprogramming: chylomicrons enriched from the lymphatics of fed mice were sufficient to enhance mitochondria of fasted T cells. LDLR-deficient T cells had the metabolic phenotype of fasted T cells and were insensitive to fed serum, confirming the role of triglyceride uptake in postprandial T cell metabolic programming. Transcriptomic analysis revealed higher expression of LDLR, OXPHOS proteins, and fatty acid metabolism enzymes in fed T cells over fasted T cells. Finally, human CAR T cells manufactured from the same donor after a meal show a therapeutic advantage over T cells collected in the fasted state. In summary, postprandial metabolism imparts durable metabolic and functional advantage on T cells. Our study highlights the need to consider diet content and timing as key factors in immune cell analysis, vaccination strategies, and the generation of cellular therapies for cancer.

Hawthorn leaf flavonoids alleviate the deterioration of atherosclerosis by inhibiting SCAP-SREBP2-LDLR pathway through sPLA2-ⅡA signaling in macrophages in mice

Ethnopharmacological relevanceHawthorn leaves are a combination of the dried leaves of the Rosaceae plants, i.e., Crataegus pinnatifida Bge. or Crataegus pinnatifida Bge. var. major N. E. Br., is primarily cultivated in East Asia, North America, and Europe. hawthorn leaf flavonoids (HLF) are the main part of extraction. The HLF have demonstrated potential in preventing hypertension, inflammation, hyperlipidemia, and atherosclerosis. However, the potential pharmacological mechanism behind its anti-atherosclerotic effect has yet to be explored. Aim of the studyThe in vivo and in vitro effects of HLF on lipid-mediated foam cell formation were investigated, with a specific focus on the levels of secreted phospholipase A2 type IIA (sPLA2-II A) in macrophage cells. Materials and methodsThe primary constituents of HLF were analyzed using ultra-high performance liquid chromatography and liquid chromatography-tandem mass spectrometry. In vivo, HLF, at concentrations of 5 mg/kg, 20 mg/kg, and 40 mg/kg, were administered to apolipoprotein E knockout mice (ApoE−/−) fed by high-fat diet (HFD) for 16 weeks. Aorta and serum samples were collected to identify lesion areas and lipids through mass spectrometry analysis to dissect the pathological process. RAW264.7 cells were incubated with oxidized low-density lipoprotein (ox-LDL) alone, or ox-LDL combined with different doses of HLF (100, 50, and 25 μg/ml), or ox-LDL plus 24-h sPLA2-IIA inhibitors, for cell biology analysis. Lipids and inflammatory cytokines were detected using biochemical analyzers and ELISA, while plaque size and collagen content of plaque were assessed by HE and the Masson staining of the aorta. The lipid deposition in macrophages was observed by Oil Red O staining. The expression of sPLA2-IIA and SCAP-SREBP2-LDLR was determined by RT-qPCR and Western blot analysis. ResultsThe chemical profile of HLF was studied using UPLC-Q-TOF-MS/MS, allowing the tentative identification of 20 compounds, comprising 1 phenolic acid, 9 flavonols and 10 flavones, including isovitexin, vitexin-4″-O-glucoside, quercetin-3-O-robibioside, rutin, vitexin-2″-O-rhamnoside, quercetin, etc. HLF decreased total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and non-high-density lipoprotein cholesterol (non-HDL-C) levels in ApoE−/− mice (P < 0.05), reduced ox-LDL uptake, inhibited level of inflammatory factors, such as IL-6, IL-8, TNF-α, and IL-1ꞵ (P < 0.001), and alleviated aortic plaques with a thicker fibrous cap. HLF effectively attenuated foam cell formation in ox-LDL-treated RAW264.7 macrophages, and reduced levels of intracellular TC, free cholesterol (FC), cholesteryl ester (CE), IL-6, TNF-α, and IL-1β (P < 0.001). In both in vivo and in vitro experiments, HLF significantly downregulated the expression of sPLA2-IIA, SCAP, SREBP2, LDLR, HMGCR, and LOX-1 (P < 0.05). Furthermore, sPLA2-IIA inhibitor effectively mitigated inflammatory release in RAW264.7 macrophages and regulated SCAP-SREBP2-LDLR signaling pathway by inhibiting sPLA2-IIA secretion (P < 0.05). ConclusionHLF exerted a protective effect against atherosclerosis through inhibiting sPLA2-IIA to diminish SCAP-SREBP2-LDLR signaling pathway, to reduce LDL uptake caused foam cell formation, and to slow down the progression of atherosclerosis in mice.

Novel Glycomimetics Protect against Glycated Low-Density Lipoprotein-Induced Vascular Calcification In Vitro via Attenuation of the RAGE/ERK/CREB Pathway.

Heparan sulphate (HS) can act as a co-receptor on the cell surface and alterations in this process underpin many pathological conditions. We have previously described the usefulness of mimics of HS (glycomimetics) in protection against β-glycerophosphate-induced vascular calcification and in the restoration of the functional capacity of diabetic endothelial colony-forming cells in vitro. This study aims to investigate whether our novel glycomimetic compounds can attenuate glycated low-density lipoprotein (g-LDL)-induced calcification by inhibiting RAGE signalling within the context of critical limb ischemia (CLI). We used an established osteogenic in vitro vascular smooth muscle cell (VSMC) model. Osteoprotegerin (OPG), sclerostin and glycation levels were all significantly increased in CLI serum compared to healthy controls, while the vascular calcification marker osteocalcin (OCN) was down-regulated in CLI patients vs. controls. Incubation with both CLI serum and g-LDL (10 µg/mL) significantly increased VSMC calcification vs. controls after 21 days, with CLI serum-induced calcification apparent after only 10 days. Glycomimetics (C2 and C3) significantly inhibited g-LDL and CLI serum-induced mineralisation, as shown by a reduction in alizarin red (AR) staining and alkaline phosphatase (ALP) activity. Furthermore, secretion of the osteogenic marker OCN was significantly reduced in VSMCs incubated with CLI serum in the presence of glycomimetics. Phosphorylation of cyclic AMP response element-binding protein (CREB) was significantly increased in g-LDL-treated cells vs. untreated controls, which was attenuated with glycomimetics. Blocking CREB activation with a pharmacological inhibitor 666-15 replicated the protective effects of glycomimetics, evidenced by elevated AR staining. In silico molecular docking simulations revealed the binding affinity of the glycomimetics C2 and C3 with the V domain of RAGE. In conclusion, these findings demonstrate that novel glycomimetics, C2 and C3 have potent anti-calcification properties in vitro, inhibiting both g-LDL and CLI serum-induced VSMC mineralisation via the inhibition of LDLR, RAGE, CREB and subsequent expression of the downstream osteogenic markers, ALP and OCN.

Novel effects of prohibitin 1 expression level on cholesterol and lipid homeostasis

Prohibitin 1 (PHB1) plays an important role in maintaining liver health and function. The PHB1 level is decreased in patients with various liver diseases. In this study, liver cancer was induced in liver-specific Phb1 knock-out mice, which were then subjected to hepatic gene and metabolomic analysis. The reduced expression of mRNA expression level of Phb1 induced down-regulation of cholesterol and lipid metabolism. This result was confirmed in a cell model. The expression of Hmgcr and Srebp2 in normal cells decreased when they were treated with cholesterol. In HepG2 cells in which the expression of Phb1 was lowered using siPhb1, the mRNA expression of Hmgcr and Srebp2 also decreased when the cells were treated with cholesterol. Furthermore, in the Phb1 knock-out group, the expression of Fasn and Srebp1 related to lipid metabolism increased but the expression of Ldlr decreased. The expression of Cat and Gpx in cells increased when the expression of Phb1 decreased. Altogether, a decreased expression of Phb1 induces down-regulation of cholesterol- and lipid metabolism-related genes and cholesterol homeostasis is not achieved, particularly in a cholesterol-rich environment. The decrease in Phb1 expression causes excessive oxidative stress in cholesterol and lipid metabolism. Therefore, maintaining a normal level of PHB1 expression is crucial for maintaining cholesterol homeostasis in the liver. Thus, PHB1 may become an important target for non-alcoholic fatty liver disease and lipid metabolism in the future.

Expression of components involved in cholesterol homeostasis maintenance during experimental autoimmune encephalomyelitis in rat spinal cord.

Dysregulations in cholesterol homeostasis contribute to the pathogenesis of multiple sclerosis (MS) and its best described animal model, experimental autoimmune encephalomyelitis (EAE). Cholesterol is an important component of myelin, which is necessary for signal transmission between neurons. Demyelination leads to the formation of oxysterols, degradation products of cholesterol that are ligands for nuclear liver X receptors (LXRs). Genes regulated by LXRs are involved in cholesterol efflux, absorption, transport, and excretion, which we investigated in this study. In this study, we detected changes in gene expression of Srebf1, Ldlr, Soat1, Abca1, Lrp1, and Npc1, all of which are important in the regulation of cholesterol homeostasis, during the course of EAE in male and female rats. In particular, differential expression of Srebf1, Ldlr, and Soat1 was observed in the spinal cord of male and female rats during EAE. Moreover, these genes are altered during EAE. In contrast, the expression of Abca1 and Lrp1 was significantly affected only by sex. In male animals, the expression of Npc1 is conspicuously reduced in EAE pathology. Thus, our study confirms the involvement of enzymes of cholesterol metabolism in the pathophysiology of EAE, with sex and disease progression affecting the expression of these genes. These findings may improve the understanding of neurodegenerative diseases associated with impaired lipid metabolism in the brain, such as MS/EAE.

Effects of konjac glucomannan intake patterns on glucose and lipid metabolism of obese mice induced by a high fat diet.

Konjac glucomannan (KGM) is a dietary fiber supplement that exhibits multiple biological activities, including weight control as well as regulation of glucose and lipid metabolism. Currently, KGM intake patterns in practical applications include KGM sol, thermal irreversible gel, and frozen thermal irreversible gel. In this study, four intake patterns of KGM, namely KGM sol (KS), deacetylated KGM (DK), KGM gel (KG), and frozen KGM gel (FKG), were used as materials to explore the effects of different KGM intake patterns on glucose and lipid metabolism and intestinal flora in obese mice induced by a high fat diet under the same dose. The results showed that any type of KGM intake could reduce body weight, fat mass, lipid levels, and insulin resistance in obese mice, and alleviate liver damage and inflammation caused by obesity. However, KS has the most significant effect on controlling blood glucose and blood lipid in obese mice. Additionally, it was found that KS, DK, KG and FKG can increase the α-diversity of intestinal microflora in high-fat mice and improve the microflora disorder in high-fat mice. Finally, KS may increase the levels of fasting appetite hormones GLP-1 and PYY in mice, up-regulate the expression of LDLR, GCK and G-6-pase mRNA, and increase the production of short-chain fatty acids (SCFAs) in the intestinal flora of mice, thus regulating glucose and lipid metabolism. This study systematically investigated the effects of different intake forms of KGM on metabolism and intestinal flora in obese mice, which is of great significance for further understanding the role of KGM in the prevention and treatment of obesity-related metabolic diseases and for developing targeted dietary interventions.

Comprehensive Analysis of the Prognostic Marker and Immune Infiltrates of LDLR-Related Proteins Family Members in Breast Cancer.

Breast cancer (BC) is one of the most frequent tumors worldwide, accounting for 15% of all cancer-related deaths. A timely diagnosis of BC is essential for optimal treatment and increasing patients' survival rates. LRP family proteins are important components of cell-surface receptors involved in numerous biological activities. Expression of LRP is related to breast malignancy. In this study, we initially studied the expression of LRPs in BC tissues compared to normal tissues-the relation of LRP expression with relapse-free survival (RFS) and overall survival (OS). Then, we investigated the association of LRPs relation and immune infiltrating abundance. We analyzed the LDLR family expression and prognostic value in BC by mining UALCAN, TIMER, and Kaplan-Meier plotter databases. Subsequently, we explored the association of LDLR expression and immune infiltrating abundance via the TIMER database. Expression levels of LRP1/2/4/9/10 were found to be higher in the cases with positive estrogen receptors. There was a positive association between LRP1/6 expression and the infiltration of CD8+ T cells, CD4+ T Cell, Macrophage, Dendritic Cell, and Neutrophil. Our study recommends LDLR as a potential prognostic biomarker that can be promising to improve the survival of BC patients' survival. However, further investigations are needed to evaluate the studied LDLR members in more detail.

Hypertensive Pressure Mechanosensing Alone Triggers Lipid Droplet Accumulation and Transdifferentiation of Vascular Smooth Muscle Cells to Foam Cells.

Arterial Vascular smooth muscle cells (VSMCs) play a central role in the onset and progression of atherosclerosis. Upon exposure to pathological stimuli, they can take on alternative phenotypes that, among others, have been described as macrophage like, or foam cells. VSMC foam cells make up >50% of all arterial foam cells and have been suggested to retain an even higher proportion of the cell stored lipid droplets, further leading to apoptosis, secondary necrosis, and an inflammatory response. However, the mechanism of VSMC foam cell formation is still unclear. Here, it is identified that mechanical stimulation through hypertensive pressure alone is sufficient for the phenotypic switch. Hyperspectral stimulated Raman scattering imaging demonstrates rapid lipid droplet formation and changes to lipid metabolism and changes are confirmed in ABCA1, KLF4, LDLR, and CD68 expression, cell proliferation, and migration. Further, a mechanosignaling route is identified involving Piezo1, phospholipid, and arachidonic acid signaling, as well as epigenetic regulation, whereby CUT&Tag epigenomic analysis confirms changes in the cells (lipid) metabolism and atherosclerotic pathways. Overall, the results show for the first time that VSMC foam cell formation can be triggered by mechanical stimulation alone, suggesting modulation of mechanosignaling can be harnessed as potential therapeutic strategy.

Discovery of (2-(4-Substituted phenyl)quinolin-4-yl)(4-isopropylpiperazin-1-yl)methanone Derivatives as Potent Proprotein Convertase Subtilisin/Kexin Type 9 Inhibitors.

Inhibition of proprotein convertase subtilisin/kexin type 9 (PCSK9) plays an increasingly important role in the treatment of hyperlipidemia. In pursuit of potent small molecules that block the PCSK9/low-density lipoprotein receptor (LDLR) protein-protein interaction (PPI), a series of 2-phenylquinoline-4-carboxylic acid derivatives were designed and synthesized based on previously derived molecules. In the in vitro PPI inhibition test, compounds M1, M12, M14, M18 and M27 exhibited potent activities with IC50 values of 6.25 μM, 0.91 μM, 2.81 μM, 4.26 μM and 0.76 μM, respectively, compared with SBC-115337 (IC50 value of 9.24 μM). Molecular docking and molecular dynamics simulations revealed the importance of hydrophobic interactions in the binding of inhibitors to the PPI interface of PCSK9. In LDLR expression and LDL uptake assays, the tested compounds M1, M12 and M14 were found to restore LDLR expression levels and to increase the extracellular LDL uptake capacity of HepG2 cells in the presence of exogenous PCSK9. Collectively, novel small-molecule PCSK9/LDLR PPI inhibitors (especially M12) with in vitro lipid lowering ability, were discovered as lead compounds for further development of hypolipidemic drugs.

Protective effects of methyl protodioscin against lipid disorders and liver injury in hyperlipidemic gerbils

Methyl protodioscin (MPD) is the main component of total diosgenin, which was reported to reduce cholesterol and triglyceride levels potentially. This study aimed to investigate the beneficial effects of MPD against lipid disorder in hyperlipidemic gerbils induced by a high-fat diet (HFD). Hyperlipidemia was induced in gerbils by feeding them with HFD for six weeks, and a daily oral dose of MPD solution (25 and 50 mg/kg/day) was administered. This study investigated blood lipid levels and hepatic lipid accumulation in hyperlipidemic gerbils. The potential mechanism of MPD was explored by detecting the expression level of genes, including SREBPs, ACC, FASN, HMGCR, PCSK9, and LDL-R. The results showed that MPD treatment decreased the body weight, the relative weight of the liver, blood lipid, and hepatic lipid levels of gerbils fed with HFD. The administration of MPD alleviates liver steatosis and injury in gerbils fed with an HFD. MPD treatment reduced the expression of HMGCR, increased the expression of LDL-R, and decreased the expression of PCSK9 for cholesterol reduction. Additionally, MPD treatment reduced the expression of hepatic ACC and FASN for triglycerides reduction. The underlying mechanisms for these effects are attributed to MPD-induced inhibition of protein expression of LXR, SREBP1, and SREBP2. This study demonstrates that MPD protects gerbils against lipid disorders and liver injury by suppressing hepatic SREBPs expression.