acyl-CoA:cholesterol Acyltransferase Research Articles

SOAT1 in gallbladder cancer: Clinicopathological significance and avasimibe therapeutics.

The aim of this investigation was to evaluate the differential expression of the sterol O-acyltransferase 1 (SOAT1) protein in gallbladder cancer tissues and cells, investigate the impact of Avastin on the proliferation, migration, invasion capabilities of gallbladder cancer cells, and its potential to induce cell apoptosis. Immunohistochemical analysis of samples from 145 gallbladder cancer patients was conducted, along with analysis of SOAT1 protein, mRNA expression levels, and cholesterol content in gallbladder cancer cell lines SGC-996, NOZ, and gallbladder cancer (GBC)-SD using Western blot and q-PCR techniques. Furthermore, the effects of Avastin on the proliferation, migration, and invasion capabilities of these gallbladder cancer cell lines were studied, and its ability to induce cell apoptosis was evaluated using flow cytometry, Western blot, and immunohistochemical methods. Additionally, gene expression and pathway analysis were performed, and the synergistic therapeutic effects of Avastin combined with gemcitabine were tested in a gallbladder cancer xenograft model. The study found that SOAT1 expression was significantly upregulated in GBC tissues and positively correlated with lymph node metastasis and TNM staging. In vitro experiments demonstrated that Avastin significantly inhibited the proliferation, migration, and invasion capabilities of SGC-996 and GBC-SD cell lines and induced apoptosis. RNA sequencing analysis revealed multiple differentially expressed genes in cells treated with Avastin, primarily enriched in biological pathways such as signaling transduction, malignant tumors, and the immune system. In vivo, experiments confirmed that Avastin could effectively suppress tumor growth in a gallbladder cancer xenograft model and enhanced the treatment efficacy when used in combination with gemcitabine. Overall, these findings provide new insights and strategies for targeted therapy in gallbladder cancer.

Sterol O-acyltransferase (SOAT/ACAT) activity is required to form cholesterol crystals in hepatocyte lipid droplets

ObjectiveExcess cholesterol storage can induce the formation of cholesterol crystals in hepatocyte lipid droplets. Such crystals distinguish metabolic dysfunction associated steatohepatitis (MASH) from simple steatosis and may underlie its pathogenesis by causing cell damage that triggers liver inflammation. The mechanism linking cholesterol excess to its crystallization in lipid droplets is unclear. As cholesteryl esters localize to and accumulate in lipid droplets more readily than unesterified free cholesterol, we investigated whether cholesterol esterification by sterol O-acyltransferase (SOAT), also known as acyl co-A cholesterol acyltransferase (ACAT), is required for hepatocyte lipid droplet crystal formation. MethodCholesterol crystals were measured in cholesterol loaded Hep3B hepatocytes, RAW264.7 macrophages, and mouse liver using polarizing light microscopy. We examined the effect of blocking SOAT activity on crystal formation and compared these results to features of cholesterol metabolism and the progression to intracellular crystal deposits. ResultsCholesterol loading of Hep3B cells caused robust levels of lipid droplet localized crystal formation in a dose- and time-dependent manner. Co-treatment with SOAT inhibitors and genetic ablation of SOAT1 blocked crystal formation. SOAT inhibitor also blocked crystal formation in low density lipoprotein (LDL) treated Hep3B cells, acetylated LDL treated RAW 264.7 macrophages, and in the liver of mice genetically predisposed to hepatic cholesterol overload and in mice with cholesterol enriched diet-induced MASH. ConclusionSOAT1-mediated esterification may underlie cholesterol crystals associated with MASH by concentrating it in lipid droplets. These findings imply that inhibiting hepatocyte SOAT1 may be able to alleviate cholesterol associated MASH. Moreover, that either a lipid droplet localized cholesteryl ester hydrolase is required for cholesterol crystal formation, or the crystals are composed of cholesteryl ester.

The Role of Fatty Acid Synthase in the Vascular Smooth Muscle Cell to Foam Cell Transition.

Vascular smooth muscle cells (VSMCs), in their contractile and differentiated state, are fundamental for maintaining vascular function. Upon exposure to cholesterol (CHO), VSMCs undergo dedifferentiation, adopting characteristics of foam cells-lipid-laden, macrophage-like cells pivotal in atherosclerotic plaque formation. CHO uptake by VSMCs leads to two primary pathways: ABCA1-mediated efflux or storage in lipid droplets as cholesterol esters (CEs). CE formation, involving the condensation of free CHO and fatty acids, is catalyzed by sterol O-acyltransferase 1 (SOAT1). The necessary fatty acids are synthesized by the lipogenic enzyme fatty acid synthase (FASN), which we found to be upregulated in atherosclerotic human coronary arteries. This observation led us to hypothesize that FASN-mediated fatty acid biosynthesis is crucial in the transformation of VSMCs into foam cells. Our study reveals that CHO treatment upregulates FASN in human aortic SMCs, concurrent with increased expression of CD68 and upregulation of KLF4, markers associated with the foam cell transition. Crucially, downregulation of FASN inhibits the CHO-induced upregulation of CD68 and KLF4 in VSMCs. Additionally, FASN-deficient VSMCs exhibit hindered lipid accumulation and an impaired transition to the foam cell phenotype following CHO exposure, while the addition of the fatty acid palmitate, the main FASN product, exacerbates this transition. FASN-deficient cells also show decreased SOAT1 expression and elevated ABCA1. Notably, similar effects are observed in KLF4-deficient cells. Our findings demonstrate that FASN plays an essential role in the CHO-induced upregulation of KLF4 and the VSMC to foam cell transition and suggest that targeting FASN could be a novel therapeutic strategy to regulate VSMC phenotypic modulation.

Cholesterol-binding motifs in STING that control endoplasmic reticulum retention mediate anti-tumoral activity of cholesterol-lowering compounds

The cGAS-STING pathway plays a crucial role in anti-tumoral responses by activating inflammation and reprogramming the tumour microenvironment. Upon activation, STING traffics from the endoplasmic reticulum (ER) to Golgi, allowing signalling complex assembly and induction of interferon and inflammatory cytokines. Here we report that cGAMP stimulation leads to a transient decline in ER cholesterol levels, mediated by Sterol O-Acyltransferase 1-dependent cholesterol esterification. This facilitates ER membrane curvature and STING trafficking to Golgi. Notably, we identify two cholesterol-binding motifs in STING and confirm their contribution to ER-retention of STING. Consequently, depletion of intracellular cholesterol levels enhances STING pathway activation upon cGAMP stimulation. In a preclinical tumour model, intratumorally administered cholesterol depletion therapy potentiated STING-dependent anti-tumoral responses, which, in combination with anti-PD-1 antibodies, promoted tumour remission. Collectively, we demonstrate that ER cholesterol sets a threshold for STING signalling through cholesterol-binding motifs in STING and we propose that this could be exploited for cancer immunotherapy.

Comprehensive prognostic and immune analysis of sterol O-acyltransferase 1 in patients with hepatocellular carcinoma.

Sterol O-acyltransferase 1 (SOAT1) is an important target in the diagnosis and treatment of liver cancer. However, the prognostic value of SOAT1 in patients with hepatocellular carcinoma (HCC) is still not clear. To investigate the correlation of SOAT1 expression with HCC, using RNA-seq and gene expression data of The Cancer Genome Atlas (TCGA)-liver hepatocellular carcinoma (LIHC) and pan-cancer. The correlation between SOAT1 expression and HCC was analyzed. Cox hazard regression models were conducted to investigate the prognostic value of SOAT1 in HCC. Overall survival and disease-specific survival were explored based on TCGA-LIHC data. Biological processes and functional pathways mediated by SOAT1 were characterized by gene ontology (GO) analysis and the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of differentially expressed genes. In addition, the protein-protein interaction network and co-expression analyses of SOAT1 in HCC were performed to better understand the regulatory mechanisms of SOAT1 in this malignancy. SOAT1 and SOAT2 were highly expressed in unpaired samples, while only SOAT1 was highly expressed in paired samples. The area under the receiver operating characteristic curve of SOAT1 expression in tumor samples from LIHC patients compared with para-carcinoma tissues was 0.748, while the area under the curve of SOAT1 expression in tumor samples from LIHC patients compared with GTEx was 0.676. Patients with higher SOAT1 expression had lower survival rates. Results from GO/KEGG and gene set enrichment analyses suggested that the PI3K/AKT signaling pathway, the IL-18 signaling pathway, the calcium signaling pathway, secreted factors, the Wnt signaling pathway, the Jak/STAT signaling pathway, the MAPK family signaling pathway, and cell-cell communication were involved in such association. SOAT1 expression was positively associated with the abundance of macrophages, Th2 cells, T helper cells, CD56bright natural killer cells, and Th1 cells, and negatively linked to the abundance of Th17 cells, dendritic cells, and cytotoxic cells. Our findings demonstrate that SOAT1 may serve as a novel target for HCC treatment, which is helpful for the development of new strategies for immunotherapy and metabolic therapy.

Gene Silencing of Angiopoietin-like 3 (ANGPTL3) Induced De Novo Lipogenesis and Lipid Accumulation in Huh7 Cell Line.

Angiopoietin-like 3 (ANGPTL3) is a hepatokine acting as a negative regulator of lipoprotein lipase (LPL). Vupanorsen, an ANGPTL3 directed antisense oligonucleotide, showed an unexpected increase in liver fat content in humans. Here, we investigated the molecular mechanism linking ANGPTL3 silencing to hepatocyte fat accumulation. Human hepatocarcinoma Huh7 cells were treated with small interfering RNA (siRNA) directed to ANGPTL3, human recombinant ANGPTL3 (recANGPTL3), or their combination. Using Western blot, Oil Red-O, biochemical assays, and ELISA, we analyzed the expression of genes and proteins involved in lipid metabolism. Oil Red-O staining demonstrated that lipid content increased after 48 h of ANGPTL3 silencing (5.89 ± 0.33 fold), incubation with recANGPTL3 (4.08 ± 0.35 fold), or their combination (8.56 ± 0.18 fold), compared to untreated cells. This effect was also confirmed in Huh7-LX2 spheroids. A total of 48 h of ANGPTL3 silencing induced the expression of genes involved in the de novo lipogenesis, such as fatty acid synthase, stearoyl-CoA desaturase, ATP citrate lyase, and Acetyl-Coenzyme A Carboxylase 1 together with the proprotein convertase subtilisin/kexin 9 (PCSK9). Time-course experiments revealed that 6 h post transfection with ANGPTL3-siRNA, the cholesterol esterification by Acyl-coenzyme A cholesterol acyltransferase (ACAT) was reduced, as well as total cholesterol content, while an opposite effect was observed at 48 h. Under the same experimental conditions, no differences in secreted apoB and PCSK9 were observed. Since PCSK9 was altered by the treatment, we tested a possible co-regulation between the two genes. The effect of ANGPTL3-siRNA on the expression of genes involved in the de novo lipogenesis was not counteracted by gene silencing of PCSK9. In conclusion, our in vitro study suggests that ANGPTL3 silencing determines lipid accumulation in Huh7 cells by inducing the de novo lipogenesis independently from PCSK9.

Heterologous Biosynthesis of the Sterol O-Acyltransferase Inhibitor Helvamide Unveils an α-Ketoglutarate-Dependent Cross-Linking Oxygenase.

We have identified the biosynthetic gene cluster (hvm) for the sterol O-acyltransferase inhibitor helvamide (1) from the genome of Aspergillus rugulosus MST-FP2007. Heterologous expression of hvm in A. nidulans produced a previously unreported analog helvamide B (5). An α-ketoglutarate-dependent oxygenase Hvm1 was shown to catalyze intramolecular cyclization of 1 to yield 5. The biosynthetic branch to the related hancockiamides and helvamides was found to be controlled by the substrate selectivity of monomodular nonribosomal peptide synthetases.

Soat2 inhibitor avasimibe alleviates acute pancreatitis by suppressing acinar cell ferroptosis.

Ferroptosis, characterized by lipid peroxidation, plays a significant role in the pathogenesis of acute pancreatitis (AP). While sterol O-acyltransferase 2 (Soat2) is known for its crucial regulatory role in cholesterol homeostasis, its involvement in the development of AP remains unreported. We conducted this study to identify the pivotal role of Soat2 in AP using transcriptomic databases. Subsequently, we confirmed its alterations through both in vitro and in vivo experimental models. Furthermore, we performed intervention with the Soat2 inhibitor avasimibe to evaluate pancreatic tissue pathology and serum enzymatic levels and observe inflammatory cell infiltration through immunohistochemistry. Additionally, changes in indicators related to ferroptosis were also observed. The results showed that in the AP mouse model, the protein and mRNA levels of Soat2 were significantly increased. Following avasimibe administration, there was a decrease in serum amylase levels, reduction in pancreatic tissue pathological damage, and attenuation of inflammatory cell infiltration. Furthermore, avasimibe administration resulted in downregulation of ferroptosis-related indicators. In conclusion, our findings suggest that the Soat2 inhibitor avasimibe protects against AP in mice through inhibition of the ferroptosis.

Abstract B081: SOAT1 as a targetable KRAS dependency in PDAC

Abstract Metabolic rewiring is an emerging hallmark of neoplasia. In pancreatic ductal adenocarcinoma (PDAC), KRAS alters myriad metabolic programs to promote cellular transformation. Among them, the cholesterol synthesis pathway has emerged as a vulnerability of cancer cells due to the importance of cholesterol in membrane fluidity and the production of isoprenoid intermediates that enable KRAS membrane localization and activation in pancreatic cancer. We recently reported that the non-essential gene SOAT1 (Sterol-O-Acyl transferase 1), encoding an enzyme that esterifies free cholesterol into an insoluble form for storage and transport, is markedly upregulated in metastatic PDAC cells. SOAT1 promotes the hyperactivation of the mevalonate synthesis pathway due to loss of negative feedback by free cholesterol, thereby leading to increased production of isoprenoids such as farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate (GGPP), which are required for RAS and RHO membrane localization and activity, respectively. Genetic ablation of Soat1 reduced RAS and RHO membrane localization and inhibited cellular proliferation and mitochondrial function in vitro, and these effects were largely rescued by exogenous FPP and GGPP. Therefore, our study nominated SOAT1 as a new candidate gene for therapeutic targeting. Based on SuFEx Click Chemistry (ASCC) technology, we have designed and synthesized a panel of drug-like candidates. The first series of Soat1 probes selectively impair the proliferation of PDAC cells that express SOAT1, reduce SOAT1 protein content in cells, and covalently bind to SOAT1. In mice, the most active SOAT1 probes were tolerated in a 28-day daily dosing study up to 120 mg/kg. Marked tumor growth inhibition was noted in mice bearing PDAC xenografts and GEMM mice treated as monotherapy with 15 mg/kg/d of the most active SOAT1 probe, and tissue analysis demonstrated tumor necrosis, decreased proliferation, and increased apoptosis. Mechanistically, SOAT1 loss or inhibition targets multiple important components of cellular transformation in PDAC including KRAS, RHO, and mitochondrial biology, and our work suggests that it is an attractive target to pursue for further drug development in this cancer. Citation Format: Wenjun Lan, Shoujun Sun, Jeremy Nigri, Josh Homer, Young Park, Astrid Deschenes, Paolo Cifani, Justin Cross, Victoria Gaeth, Sunny Kim, Shawn Ting, Rachel Rubino, John Moses, David Tuveson. SOAT1 as a targetable KRAS dependency in PDAC [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr B081.

ACAT2 may be a novel predictive biomarker and therapeutic target in lung adenocarcinoma.

Acyl-coenzyme A cholesterol acyltransferase (ACAT) is a membrane-binding enzyme localized in the endoplasmic reticulum. ACAT2 can promote the development of colon cancer, but its efficacy in lung adenocarcinoma (LUAD) remains uncertain. ACAT2 expression was performed by using the TIMER2.0 database. The GEPIA database was utilized to analyze the correlation between ACAT2 expression and pathological stage of the tumor. Clinical prognosis was assessed through the Kaplan-Meier analysis. The CancerSEA database was employed to scrutinize the correlations between the ACAT2 expression and the functional status of various tumors, which were subsequently visualized as a heatmap. Furthermore, molecular interaction network analysis was performed by the STRING tool. High ACAT2 expression was associated with a poor DFS and OS in LUAD patients. Cox regression analysis indicated that the poor outcomes may be related to tumor stage, nodal stage, distant metastatic stage. ACAT2 was found to play a crucial role in various biological processes, including the cell cycle, DNA repair, DNA damage response, and proliferation. Enrichment pathway analysis revealed four ACAT2 related genes, ACOX1, EHHADH, OXCT1, and DLAT. Our study showed that ACAT2 was upregulated in LUAD, and had a worse survival. ACAT2 could be a novel predictive biomarker and therapeutic target in LUAD.

Fatty acids abrogate the growth-suppressive effects induced by inhibition of cholesterol flux in pancreatic cancer cells

BackgroundDespite therapeutic advances, the prognosis of pancreatic ductal adenocarcinoma (PDAC) remains extremely poor. Metabolic reprogramming is increasingly recognized as a key contributor to tumor progression and therapy resistance in PDAC. One of the main metabolic changes essential for tumor growth is altered cholesterol flux. Targeting cholesterol flux appears an attractive therapeutic approach, however, the complex regulation of cholesterol balance in PDAC cells remains poorly understood.MethodsThe lipid content in human pancreatic duct epithelial (HPDE) cells and human PDAC cell lines (BxPC-3, MIA PaCa-2, and PANC-1) was determined. Cells exposed to eight different inhibitors targeting different regulators of lipid flux, in the presence or absence of oleic acid (OA) stimulation were assessed for changes in viability, proliferation, migration, and invasion. Intracellular content and distribution of cholesterol was assessed. Lastly, proteome profiling of PANC-1 exposed to the sterol O-acyltransferase 1 (SOAT1) inhibitor avasimibe, in presence or absence of OA, was performed.ResultsPDAC cells contain more free cholesterol but less cholesteryl esters and lipid droplets than HPDE cells. Exposure to different lipid flux inhibitors increased cell death and suppressed proliferation, with different efficiency in the tested PDAC cell lines. Avasimibe had the strongest ability to suppress proliferation across the three PDAC cell lines. All inhibitors showing cell suppressive effect disturbed intracellular cholesterol flux and increased cholesterol aggregation. OA improved overall cholesterol balance, reduced free cholesterol aggregation, and reversed cell death induced by the inhibitors. Treatment with avasimibe changed the cellular proteome substantially, mainly for proteins related to biosynthesis and metabolism of lipids and fatty acids, apoptosis, and cell adhesion. Most of these changes were restored by OA.ConclusionsThe study reveals that disturbing the cholesterol flux by inhibiting the actions of its key regulators can yield growth suppressive effects on PDAC cells. The presence of fatty acids restores intracellular cholesterol balance and abrogates the alternations induced by cholesterol flux inhibitors. Taken together, targeting cholesterol flux might be an attractive strategy to develop new therapeutics against PDAC. However, the impact of fatty acids in the tumor microenvironment must be taken into consideration.

Reversible translocation of acyl-CoA:cholesterol acyltransferase (ACAT) between the endoplasmic reticulum and vesicular structures.

The enzyme acyl-CoA:cholesterol acyltransferase (ACAT) is normally localized in the endoplasmic reticulum (ER) where it can esterify cholesterol for storage in lipid droplets and/or the formation of lipoproteins. Here, we report that ACAT can translocate from the ER into vesicular structures in response to different ACAT inhibitors. The translocation was fast (within minutes), reversible and occurred in different cell types. Interestingly, oleic acid was able to fasten the re-translocation from vesicles back into the reticular ER network. The process of ACAT translocation could also be induced by cyclodextrins, cholesterol, lanosterol (but not 4-cholestene-3 one), 25-hydroxycholesterol, and by certain stress stimuli such as hyperosmolarity (sucrose treatment), temperature change, or high-density cultivation. In vitro esterification showed that ACAT remains fully active after it has been translocated to vesicles in response to hyperosmotic sucrose treatment of the cells. The translocation process was not accompanied by changes in the electrophoretic mobility of ACAT, even after chemical crosslinking. Interestingly, the protein synthesis inhibitor cycloheximide showed a stimulating effect on ACAT activity and prevented the translocation of ACAT from the ER into vesicles.

Cholesterol Metabolism in Pancreatic Cancer.

Pancreatic cancer's substantial impact on cancer-related mortality, responsible for 8% of cancer deaths and ranking fourth in the US, persists despite advancements, with a five-year relative survival rate of only 11%. Forecasts predict a 70% surge in new cases and a 72% increase in global pancreatic cancer-related deaths by 2040. This review explores the intrinsic metabolic reprogramming of pancreatic cancer, focusing on the mevalonate pathway, including cholesterol biosynthesis, transportation, targeting strategies, and clinical studies. The mevalonate pathway, central to cellular metabolism, significantly shapes pancreatic cancer progression. Acetyl coenzyme A (Acetyl-CoA) serves a dual role in fatty acid and cholesterol biosynthesis, fueling acinar-to-ductal metaplasia (ADM) and pancreatic intraepithelial neoplasia (PanIN) development. Enzymes, including acetoacetyl-CoA thiolase, 3-hydroxy-3methylglutaryl-CoA (HMG-CoA) synthase, and HMG-CoA reductase, are key enzymes in pancreatic cancer. Inhibiting HMG-CoA reductase, e.g., by using statins, shows promise in delaying PanIN progression and impeding pancreatic cancer. Dysregulation of cholesterol modification, uptake, and transport significantly impacts tumor progression, with Sterol O-acyltransferase 1 (SOAT1) driving cholesterol ester (CE) accumulation and disrupted low-density lipoprotein receptor (LDLR) expression contributing to cancer recurrence. Apolipoprotein E (ApoE) expression in tumor stroma influences immune suppression. Clinical trials targeting cholesterol metabolism, including statins and SOAT1 inhibitors, exhibit potential anti-tumor effects, and combination therapies enhance efficacy. This review provides insights into cholesterol metabolism's convergence with pancreatic cancer, shedding light on therapeutic avenues and ongoing clinical investigations.

Characterization of thraustochytrid-specific sterol O-acyltransferase: modification of DGAT2-like enzyme to increase the sterol production in Aurantiochytrium limacinum mh0186.

Since the global market for sterols and vitamin D are grown with a high compound annual growth rate, a sustainable source of these compounds is required to keep up with the increasing demand. Thraustochytrid is a marine oleaginous microorganism that can synthesize several sterols, which are stored as SE in lipid droplets. DGAT2C is an unconventional SE synthase specific to thraustochytrids. Although the primary structure of DGAT2C shows high similarities with that of DGAT, DGAT2C utilizes sterol as an acceptor substrate instead of diacylglycerol. In this study, we examined more detailed enzymatic properties, intracellular localization, and structure-activity relationship of DGAT2C. Furthermore, we successfully developed a method to increase sterol and provitamin D3 productivity of thraustochytrid by more than threefold in the process of elucidating the function of the DGAT2C-specific N-terminal region. Our findings could lead to sustainable sterol and vitamin D production using thraustochytrid.

Sparassis latifolia Polysaccharide Attenuates Cholesterol in Rats Maintained on a High-Fat, High-Cholesterol Diet

Sparassis latifolia polysaccharide (SLP) has broad application prospects as a raw material of functional food. This study aimed to investigate the effects of SLP on liver cholesterol metabolism and its mechanism. Sprague–Dawley rats were fed a high-fat, high-cholesterol diet, and various assessments were conducted including hematoxylin and eosin staining, measurement of liver and metabolic indices, and antioxidant analysis. In addition, fluorescence quantitative reverse transcription-polymerase chain reaction was performed to analyze mRNA expression, and gas chromatography-mass spectrometry was employed for screening differential metabolites. The results demonstrated that SLP reduced the abnormal increase in the liver index caused by high fat and cholesterol and improved liver tissue morphology, metabolism level, and antioxidant-related enzyme activities. The polysaccharide regulated the liver sterol metabolism pathway, decreased the mRNA expression levels of 3-hydroxy-3-methylglutaryl-CoA reductase (HMG-CoAR) and sterol O-acyltransferase 1 (SOAT1), upregulated the mRNA expression levels of cholesterol 7α hydroxylase (CYP7α-1) and ABCA1, and increased the contents of propionic acid and butyric acid in the liver. These findings indicated a novel pathway through which SLP prevented hepatic lipid deposition and ameliorated sterol metabolism via regulating the HMG-CoAR-CYP7α-1 axis.

The metabolic adaptation of bile acids and cholesterol after biliary atresia in lamprey via transcriptome-based analysis

Lamprey underwent biliary atresia (BA) at its metamorphosis stage. In contrast to patients with BA who develop progressive disease, lamprey can grow and develop normally, suggesting that lamprey has several adaptations for BA. Here we show that adaptive changes in bile acid and cholesterol metabolism are produced after lamprey BA. Among 1102 differentially expressed genes (DGEs) after BA in lamprey, many are enriched in gene ontology (GO) terms and pathways related to steroid metabolism. We find that among the DGEs related to bile acids and cholesterol metabolism, the expression of cytochrome P450 family 7 subfamily A member 1 (CYP7A1), sodium-dependent taurine cotransport polypeptide (NTCP) are significantly downregulated, whereas nuclear receptor farnesoid X receptor (FXR), multidrug resistance-associated protein 3 (MRP3), 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), sterol O-acyltransferase 1 (SOAT1), and ATP binding cassette subfamily A member 1 (ABCA1) are remarkably upregulated. The changes in expression level are also validated by RT-qPCR. Furthermore, the level of high-density lipoprotein-cholesterol (HDL-C) and low-density lipoprotein-cholesterol (LDL-C) in juvenile serum is higher compared to larvae. Taken together, the findings collectively indicate that after BA, lamprey may maintain bile acids and cholesterol homeostasis in liver tissue by inhibiting bile acids synthesis and uptake, promoting its efflux back to circulation, and enhancing cholesterol esterification for storage as lipid droplets and its egress to form nascent HDL (nHDL). Understanding the possible molecular mechanisms of lamprey metabolic adaptation sheds new light on the understanding of the development and treatment of diseases caused by abnormal bile acid and cholesterol metabolism in humans.

Regulation of cholesterol metabolism during high fatty acid–induced lipid deposition in calf hepatocytes

Cholesterol in the circulation is partly driven by changes in feed intake, but aspects of cholesterol metabolism during development of fatty liver are not well known. The objective of this study was to investigate mechanisms of cholesterol metabolism in calf hepatocytes challenged with high concentrations of fatty acids (FA). To address mechanistic insights regarding cholesterol metabolism, liver samples were collected from healthy control dairy cows (n = 6; 7-13 d in milk) and cows with fatty liver (n = 6; 7-11 d in milk). In vitro, hepatocytes isolated from 3 healthy female calves (1 d old) were challenged with or without a mix of 1.2 mM FA to induce metabolic stress. In addition, hepatocytes were processed with 10 µmol/L of the cholesterol synthesis inhibitor simvastatin or 6 µmol/L of the cholesterol intracellular transport inhibitor U18666A with or without the 1.2 mM FA mix. To evaluate the role of cholesterol addition, hepatocytes were treated with 0.147 mg/mL methyl-β-cyclodextrin (MβCD + FA) or 0.147 mg/mL MβCD with or without 10 and 100 µmol/L cholesterol before incubation with FA (CHO10 + FA and CHO100 + FA). In vivo data from liver biopsies were analyzed by 2-tailed unpaired Student's t-test. Data from in vitro calf hepatocytes were analyzed by one-way ANOVA. Compared with healthy cows, blood plasma total cholesterol and plasma low-density lipoprotein cholesterol content in cows with fatty liver was markedly lower, whereas the hepatic total cholesterol content did not differ. In contrast, compared with healthy controls, the triacylglycerol content in the liver and the content of FA, β-hydroxybutyrate, and aspartate aminotransferase in the plasma of cows with fatty liver were greater. The results revealed that both fatty liver in vivo and challenge of calf hepatocytes with 1.2 mM FA in vitro led to greater mRNA and protein abundance of sterol regulatory element binding transcription factor 1 (SREBF1) and fatty acid synthase (FASN). In contrast, mRNA and protein abundance of sterol regulatory element binding transcription factor 2 (SREBF2), acyl coenzyme A-cholesterol acyltransferase, and ATP-binding cassette subfamily A member 1 (ABCA1) were lower. Compared with the FA group, the cholesterol synthesis inhibitor simvastatin led to greater protein abundance of microsomal triglyceride transfer protein and mRNA abundance of SREBF2, 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), ACAT2, and lower ABCA1 and FASN protein abundance. In contrast, compared with the FA group, the cholesterol intracellular transport inhibitor U18666A + FA led to greater total cholesterol concentration and greater protein and mRNA abundance of FASN. Compared with the MβCD + FA group, the addition of 10 µmol/L cholesterol led to greater concentration of cholesteryl ester and excretion of apolipoprotein B100, and greater protein and mRNA abundance of ABCA1 and microsomal triglyceride transfer protein, and lower concentration of malondialdehyde. Overall, a reduction in cholesterol synthesis promoted FA metabolism in hepatocytes likely to relieve the oxidative stress caused by the high FA load. The data suggest that maintenance of normal cholesterol synthesis promotes very low-density lipoprotein excretion and can reduce lipid accumulation and oxidative stress in dairy cows that experience fatty liver.

Efektivitas Ekstrak Daun Annona Muricata Terhadap Penurunan Kolesterol Total Pada Lansia Dengan Hiperkolesterolemia Di Panti Werdha Mojopahit Mojokerto

The elderly experience a decrease in function, especially in the function of blood circulation. Blood circulation diseases and hormonal metabolism disorders experienced by the elderly include hypercholesterolemia. Hypercholesterolemia is a disorder of fat metabolism that triggers an increase in total blood cholesterol levels, namely> 200 mg/dl. The study aimed to determine the effectiveness of A. muricata leaf extract in decreasing total cholesterol levels in the elderly with hypercholesterolemia. Quantitative research method, using a quasi-experimental type with a group pretest-posttest design, with a sample size of 20 elderly. The sampling technique used purposive sampling, was carried out for a week consuming three times a day. The paired t-test showed a value of 8.73 and a p-value of 0.001. This study's results indicated a significant difference between the average cholesterol levels in the pre-test and post-test administration of Annona Muricata leaf extract. Compounds contained in soursop leaves, namely flavonoids, by reducing the activity of HMG-koa reductase (enzyme β-Hydroxy β-methylglutaryl-CoA) can reduce the activity of ACAT (enzyme acyl-Coa cholesterol acyltransferase), and reduce the absorption activity of cholesterol in the liver. Digestive tract. Saponin compounds in soursop leave lower cholesterol by binding to cholesterol in the intestinal lumen, thereby preventing the reabsorption of cholesterol. Saponins can bind with bile acids, which in turn will reduce the enterohepatic circulation of bile acids and cause an increase in the process of excretion of cholesterol.

Targeting sterol-O-acyltransferase 1 to disrupt cholesterol metabolism for cancer therapy.

Cholesterol esterification is often dysregulated in cancer. Sterol O-acyl-transferase 1 (SOAT1) plays an important role in maintaining cellular cholesterol homeostasis by catalyzing the formation of cholesterol esters from cholesterol and long-chain fatty acids in cells. Many studies have implicated that SOAT1 plays a vital role in cancer initiation and progression and is an attractive target for novel anticancer therapy. In this review, we provide an overview of the mechanism and regulation of SOAT1 in cancer and summarize the updates of anticancer therapy targeting SOAT1.

DNA methyltransferase 1 deficiency improves macrophage motility and wound healing by ameliorating cholesterol accumulation

Healing of the cutaneous wound requires macrophage recruitment at the sites of injury, where chemotactic migration of macrophages toward the wound is regulated by local inflammation. Recent studies suggest a positive contribution of DNA methyltransferase 1 (Dnmt1) to macrophage pro-informatory responses; however, its role in regulating macrophage motility remains unknown. In this study, myeloid-specific depletion of Dnmt1 in mice promoted cutaneous wound healing and de-suppressed the lipopolysaccharides (LPS)-inhibited macrophage motility. Dnmt1 inhibition in macrophages eliminated the LPS-stimulated changes in cellular mechanical properties in terms of elasticity and viscoelasticity. LPS increased the cellular accumulation of cholesterol in a Dnmt1-depedent manner; cholesterol content determined cellular stiffness and motility. Lipidomic analysis indicated that Dnmt1 inhibition altered the cellular lipid homeostasis, probably through down-regulating the expression of cluster of differentiation 36 CD36 (facilitating lipid influx) and up-regulating the expression of ATP-binding cassette transporter ABCA1 (mediating lipid efflux) and sterol O-acyltransferase 1 SOAT1 (also named ACAT1, catalyzing the esterification of cholesterol). Our study revealed a Dnmt1-dependent epigenetic mechanism in the control of macrophage mechanical properties and the related chemotactic motility, indicating Dnmt1 as both a marker of diseases and a potential target of therapeutic intervention for wound healing.