Cholesterol Balance Research Articles

Discovery of Spiro[pyrrolidine-3,3'-oxindole] LXRβ Agonists for the Treatment of Osteoporosis.

Osteoclasts have an additional demand for cholesterol compared to normal cells. Liver X receptors (LXRs) are famous for regulation of lipid and cholesterol metabolism. Therefore, we propose that the LXR β agonist can regulate the cholesterol balance in osteoclasts to inhibit osteoclast differentiation. Here, we designed and synthesized a novel LXRβ agonist by introduction of the privileged fragments from anti-osteoporosis agents to the spiro[pyrrolidine-3,3'-oxindole] scaffold which is a novel scaffold of LXR agonists in our previous research. As a result, seven LXRβ agonists inhibited osteoclastogenesis with IC50 values ranging from 0.078 to 0.36 μM. Especially, the most potent LXRβ agonist B9 significantly inhibited RANKL-induced osteoclast differentiation and bone resorption in vitro and in vivo. Furthermore, B9 selectively activated LXRβ to promote intracellular cholesterol exclusion in osteoclasts and reduce extracellular cholesterol uptake and thereby inhibited osteoclast production. This study provides a new strategy to develop LXRβ agonists for osteoporosis.

Caffeic acid protects against atherosclerotic lesions and cognitive decline in ApoE−/− mice

Caffeic acid has been indicated to benefit cholesterol balance, but the effect of pure caffeic acid on atherosclerosis in vivo has not been tested. Given that atherosclerosis and Alzheimer's disease share common features including distracted lipid balance and chronic inflammation, the concurrent effects of caffeic acid on atherosclerotic lesions and cognitive decline were explored here by using the ApoE−/− mice model. A two months' administration of 20 mg/kg caffeic acid or saline was given once two days intraperitoneally to 5-month-old female ApoE−/− mice. We found that the caffeic acid treatment reduced the atherosclerotic lesions in the whole aorta and aortic sinus of the resulting 7-month-old ApoE−/− mice by roughly 50%, compared with the saline control. Meanwhile, the cognitive decline of treated mice were significantly alleviated, as measured by Y-maze and Morris water maze tasks. A reduced accumulation of β-amyloid in the hippocampus was also observed. These effects were associated with elevated serum HDL-c concentration, upregulated ABCA1 and ABCG1 mRNA levels, as well as decrease local inflammation and reduced levels of serum pro-inflammatory cytokines including TNF-α, IL-6 and MCP-1. These obtained results suggested the preventive and therapeutic potential of caffeic acid against atherosclerosis and Alzheimer's disease during aging.

The Effect of Healthy Lifestyle Changes on Work Ability and Mental Health Symptoms: A Randomized Controlled Trial.

Objective: The effects of lifestyle interventions on the prevention of a decline in work ability and mental health are not well known. The aim of this randomized controlled trial was to examine the effects of healthy lifestyle changes on work ability, sleep, and mental health. Methods: Workers aged 18–65 years, who were free from cardiovascular diseases, diabetes, and malignant diseases, and did not use medication for obesity or lipids were included (N = 319). Based on their cholesterol balance, participants were classified into medium-risk and high-risk groups and were randomized into four arms: group lifestyle coaching (N = 107), individual lifestyle coaching (N = 53), the control group for group coaching (N = 106), and the control group for individual coaching (N = 53). The intervention groups received eight sessions of mostly remote coaching for 8 weeks about healthy diet, physical activity, other lifestyle habits, and sources/management of stress and sleep problems, and the control groups received no intervention. In individual coaching, the coach focused more on individual problem solving and the possibilities for motivation and change. The intention-to-treat principle was applied, and missing data on the outcomes were imputed using multiple imputation. Results: After the completion of the intervention, the risk of depressive symptoms was lower by 53% (95% CI 1–77%) in participants who received individual lifestyle coaching compared with the control group. The intervention had no beneficial effects on anxiety, work ability, sleep duration, or daily stress. In subgroup analyses, group lifestyle coaching had beneficial effects on depressive symptoms and work ability in participants with less tight schedules or less stretching work, whereas individual lifestyle coaching lowered the risk of depressive symptoms in those with fewer overlapping jobs, less tight schedules, or less stretching work. Conclusion: Short but intensive remote lifestyle coaching can reduce depressive symptoms and improve work ability, and time-related resources at work may improve mental health in the context of individual lifestyle intervention. However, further randomized controlled trials are needed to confirm the findings.

Gut microbiota is a potential goalkeeper of dyslipidemia.

Dyslipidemia, as a common metabolic disease, could cause atherosclerosis, coronary heart disease, stroke and other cardio-cerebrovascular diseases. It is mainly caused by the interaction of genetic and environmental factors and its incidence has increased for several years. A large number of studies have shown that gut microbiota disorder is related to the development of dyslipidemia closely. Especially its metabolites such as short-chain fatty acids, bile acids and trimethylamine N-oxide affect dyslipidemia by regulating cholesterol balance. In this paper, we systematically reviewed the literature and used knowledge graphs to analyze the research trends and characteristics of dyslipidemia mediated by gut microbiota, revealing that the interaction between diet and gut microbiota leads to dyslipidemia as one of the main factors. In addition, starting from the destruction of the dynamic balance between gut microbiota and host caused by dyslipidemia, we systematically summarize the molecular mechanism of gut microbiota regulating dyslipidemia and provide a theoretical basis for the treatment of dyslipidemia by targeting the gut microbiota.

Changes in High-Density Lipoprotein (HDL), Low-Density Lipoprotein (LDL) and Cholesterol Concentration in Heavy Cannabis Users: A Single-Centre Study in Cusco, Peru

Background: The effect of cannabis on cholesterol and lipid balance has been reported for decades. However, there are conflicting reports on the reduction of low-density lipoprotein (LDL-C) and total cholesterol. The purpose of this study was to determine the immediate changes of Cannabis spp. consumption by pyrolytic route in heavy users. Methods: A cross-sectional study on 20 Peruvian heavy cannabis users (mean age: 31 ± 9.5 years). The inclusion criteria were males with an average weight of 50–70 kg, normal BMI, and having used cannabis, without association with other drugs, for at least one year with a high frequency per week (use: 4–7 days/week). High-density lipoprotein (HDL-C), LDL-C, and total cholesterol were evaluated 30 and 120 min after the administration of Cannabis spp. (~0.2 g by inhalation). Results: Of the total 12 (60%), 10 (50%), and 11 (55%) had desirable total cholesterol, fairly good HDL-C (40–60 mg/dL) and fairly good LDL-C (100–129 mg/dL) values, respectively. The mean basal concentration of total cholesterol, HDL-cholesterol, and LDL-cholesterol was 193.37 ± 20.18 mg/dL, 60.05 ± 6.36 mg/dL, and 129.65 ± 14.50 mg/dL, respectively. HDL-cholesterol showed progressive increases in participants with desirable HDL-C > 60 mg/dL at 30 min (10 vs. 14 participants, p < 0.001) and at 120 min (10 vs. 16 participants, p < 0.001), while LDL-C peaked in participants with concentrations < 100 mg/dL at 30 min (desirable cholesterol: 0 vs. 2, p = 0.001). HDL-C concentration showed differences after cannabis consumption, showing increases at 30 (63.25 ± 7.68 mg/dL) and 120 min (69.15 ± 18.67 mg/dL) and total cholesterol concentration changed to 180.95 ± 19.3 mg/dL (95%CI 172.5 to 189.4) at 120 min (p = 0.007). Conclusions: HDL-C cholesterol increased 30 and 120 min after Cannabis spp. ingestion, while LDL-C and total cholesterol showed partial reductions in heavy-users from Cusco, Peru.

*Ketogenic Diets Exacerbating Hypercholesterolemia in APOE Variants and APOB Mutations-Potential Role for Measuring Intestinal Absorption of Lipids

Lead Author's Financial Disclosures Nothing to disclose. Study Funding None. Background/Synopsis Familial Hypercholesterolemia (FH) is caused primarily by mutations in either LDL receptor, APOB, or PCSK9 genes. There are other genetic causes of LDL elevation including APOE4 variants. Objective/Purpose We present two patients with markedly elevated LDL suspicious for FH who were subsequently diagnosed with APOE3/4 variants while on ketogenic diets. We also present a patient with a known APOB mutation who had a marked elevation of LDL on a ketogenic diet. Methods Case 1: 58-year-old male with no prior medical history was found to have elevated cholesterol of 600mg/dL and LDL>455mg/dL while on a ketogenic diet. Prior to initiating the diet, his cholesterol was 206mg/dL and LDL was 132mg/dL. Genetic testing revealed a ApoE3/4 variant. His most recent cholesterol increased to 706mg/dL and LDL to >500mg/dL. Case 2: 53-year-old male with hypertension cholesterol of 282mg/dL and LDL of 212mg/dL went on a ketogenic diet and lost 100lbs. Follow up lipid panel demonstrated a cholesterol of 400mg/dL and LDL of 317mg/dL. Genetic testing revealed a APOE3/4 variant. Case 3: 45-year-old female with FH and known APOB missense mutation went on a ketogenic diet for weight loss. Prior to initiating the diet, her total cholesterol was 311 mg/dL and LDL was 211 mg/dL. While on the ketogenic diet, her total cholesterol was 550 mg/dL and LDL was 454 mg/dL. Her LDL decreased to 276mg/dl on a less strict ketogenic diet. Results All three patients had a normal exercise stress test, normal carotid duplex ultrasound, and coronary calcium score of zero. They refused the initiation of a statin. All 3 patients had the Boston Heart Cholesterol Balance Test performed that directly measures the absorption markers (beta-sitosterol, campesterol and cholestanol) for circulating plasma cholesterol. Only the patient with the APOB mutation had increased intestinal absorption of cholesterol, suggesting a response to ezetimibe. She agreed to initiate ezetimibe, her LDL subsequently decreased by 52% to 132mg/dl. Conclusions We hypothesize patients with APOE variants and APOB mutations could have an exaggerated elevation of their LDL levels while on ketogenic diets. Although these 3 patients did not demonstrate progressive atherosclerosis, the long-term effect of this diet is unknown. We recommend that all patients on a ketogenic diet have their LDL monitored and if there is a significant increase, undergo genetic testing for FH, APOE and other genetic variants. Since this patient group is often reluctant to start statins, the Cholesterol Balance Test may be useful to identify patients who may respond well to ezetimibe. Nothing to disclose.

Suppression of the ABCA1 Cholesterol Transporter Impairs the Growth and Migration of Epithelial Ovarian Cancer.

Simple SummaryEpithelial ovarian cancer (EOC) is the most lethal gynaecological cancer. Over 80% of cases have already spread at diagnosis, and these patients face a five-year survival rate of 35%. EOC cells often spread to the greater omentum, an abdominal fat pad. Here, EOC cells take-up cholesterols. Excessive amounts of cholesterol are lethal; thus, we proposed that the ABCA1 cholesterol transporter exports cholesterol from serous EOC cells to maintain cholesterol balance. Indeed, we found that reducing the level of ABCA1 could suppress serous EOC growth in two-dimensional as well as three-dimensional cell culture and also hindered their migration, a key process required for cancer spread. We also identified drugs that impair EOC cell growth by inhibiting cholesterol export. Our data demonstrate that disrupting the cholesterol balance by targeting ABCA1 may be an effective treatment strategy for EOC patients.Background: Epithelial ovarian cancer (EOC) is the most lethal gynaecological malignancy with over 80% of cases already disseminated at diagnosis and facing a dismal five-year survival rate of 35%. EOC cells often spread to the greater omentum where they take-up cholesterol. Excessive amounts of cholesterol can be cytocidal, suggesting that cholesterol efflux through transporters may be important to maintain homeostasis, and this may explain the observation that high expression of the ATP-binding cassette A1 (ABCA1) cholesterol transporter has been associated with poor outcome in EOC patients. Methods: ABCA1 expression was silenced in EOC cells to investigate the effect of inhibiting cholesterol efflux on EOC biology through growth and migration assays, three-dimensional spheroid culture and cholesterol quantification. Results: ABCA1 suppression significantly reduced the growth, motility and colony formation of EOC cell lines as well as the size of EOC spheroids, whilst stimulating expression of ABCA1 reversed these effects. In serous EOC cells, ABCA1 suppression induced accumulation of cholesterol. Lowering cholesterol levels using methyl-B-cyclodextrin rescued the effect of ABCA1 suppression, restoring EOC growth. Furthermore, we identified FDA-approved agents that induced cholesterol accumulation and elicited cytocidal effects in EOC cells. Conclusions: Our data demonstrate the importance of ABCA1 in maintaining cholesterol balance and malignant properties in EOC cells, highlighting its potential as a therapeutic target for this disease.

Dealkenylation of neoandrographolide, a phytochemical from Andrographis paniculata stimulates FXR (Farnesoid X Receptor) and enhances gallstone dissolution

FXR (Farnesoid X Receptor) is one of the nuclear receptors expressed in the liver performing a significant role in the maintenance of bile acid concentration. An imbalance of cholesterol and bile acid ratio due to any undefined reason could cause gallstone formation. Hence, this paper aims to screen phytochemicals that could maintain a requisite balance of cholesterol and bile acid by targeting FXR and thereby contributing to the dissolution of gallstone. Nineteen phytochemicals were selected and queried for Pa and Pi in the way2drug online server for hepatoprotective property, cholesterol synthesis and absorption inhibition property, and β-glucuronidase inhibiting activity. Cianidanol, neoandrographolide, cynarine, saponins, and tanins with satisfying stated properties were docked with the screened FXR (PDB ID- 1OSH) using HADDOCK server, followed by pharmacokinetics study utilizing SwissADME tool. Neoandrographolide fits best among the other selected literature-based phytochemicals with minor violation of ‘Brenk’s rule’. The violation was corrected with the removal of an alkene group in the provided ChemDraw space of SwissADME. This Dealkenylated compound was further docked with FXR. The promising response under the static condition of the Dealkenylated compound was analyzed for molecular dynamic simulation at physiological conditions for 100 ns. Dealkenylated Neoandrographolide (DN) exhibited hepatoprotective, cholesterol synthesis and absorption inhibition property, and β-glucuronidase inhibition activity with a superior binding score of −42.6+/-1.5 with FXR. The interaction of the FXR receptor and the DN showed exceptional stability at physiological conditions during MD simulation and fit for the ADME properties, therefore it could be a potent candidate to dissolve gallstones. Communicated by Ramaswamy H. Sarma.

Daily intake of up to two eggs for 11weeks does not affect the cholesterol balance of Chinese young adults.

Approximately 90% of the cholesterol content of the body is derived from de novo synthesis and the enterohepatic circulation. As numerous studies have shown previously, one egg per day intake has little impact of cholesterol balance in human body. Therefore, this study assumed that intake of up two eggs a day has little effect on biomarkers of cardiovascular diseases (CVDs) risk in Chinese young adults. With the increase in egg intake, total cholesterol, low‐density lipoprotein cholesterol (LDL‐C), high‐density lipoprotein cholesterol (HDL‐C), and choline all increased among all the groups as the study progressed from autumn to winter (p < .05). However, there were no differences in the plasma triglycerides, LDL‐C/HDL‐C ratio, glucose, liver enzymes, C‐reactive protein, and urinary microalbumin during the diet periods. Subjects who ate eggs at breakfast felt less hungry and more satisfied, which were relative with decreased fasting plasma ghrelin level (p < .05). Furthermore, egg‐derived cholesterol appeared to upregulate the mRNA levels of low‐density lipoprotein receptor and lecithin–cholesterol acyltransferase, and downregulate cholesteryl ester transfer protein and flavin‐containing monooxygenase 3 mRNA levels in isolated peripheral blood mononuclear cells. These results demonstrate that intake of up to two eggs a day had little effect on biomarkers of CVDs in young, healthy Chinese college students and provided useful evidence for the dietary guidelines regarding egg consumption.

The Bioavailability and Biological Activities of Phytosterols as Modulators of Cholesterol Metabolism.

Phytosterols are natural sterols widely found in plants that have a variety of physiological functions, and their role in reducing cholesterol absorption has garnered much attention. Although the bioavailability of phytosterols is only 0.5–2%, they can still promote cholesterol balance in the body. A mechanism of phytosterols for lowering cholesterol has now been proposed. They not only reduce the uptake of cholesterol in the intestinal lumen and affect its transport, but also regulate the metabolism of cholesterol in the liver. In addition, phytosterols can significantly reduce the plasma concentration of total cholesterol, triglycerides, and low-density lipoprotein cholesterol (LDL-C), with a dose-response relationship. Ingestion of 3 g of phytosterols per day can reach the platform period, and this dose can reduce LDL-C by about 10.7%. On the other hand, phytosterols can also activate the liver X receptor α-CPY7A1 mediated bile acids excretion pathway and accelerate the transformation and metabolism of cholesterol. This article reviews the research progress of phytosterols as a molecular regulator of cholesterol and the mechanism of action for this pharmacological effect.

The Medicinal Chemistry and Therapeutic Potential of LRH-1 Modulators.

The ligand-activated transcription factor liver receptor homologue 1 (LRH-1, NR5A2) is involved in the regulation of metabolic homeostasis, including cholesterol and glucose balance. Preliminary evidence points to therapeutic potential of LRH-1 modulation in diabetes, hepatic diseases, inflammatory bowel diseases, atherosclerosis, and certain cancers, but because of a lack of suitable ligands, pharmacological control of LRH-1 has been insufficiently studied. Despite the availability of considerable structural knowledge on LRH-1, only a few ligand chemotypes have been developed, and potent, selective, and bioavailable tools to explore LRH-1 modulation in vivo are lacking. In view of the therapeutic potential of LRH-1 in prevalent diseases, improved chemical tools are needed to probe the beneficial and adverse effects of pharmacological LRH-1 modulation in sophisticated preclinical models and to further elucidate the receptor's molecular function.

Bioinformatics and wet laboratory analysis of rs1800562 to predict genetic aetiology of iron overload in Nigeria

Abstract Introduction/Objective The most reported single nucleotide polymorphism (SNP) of the HFE gene is rs1800562, representing the substitution of Adenine for Guanine at position 847 of the HFE gene. This has been widely implicated in hereditary haemochromatosis and other conditions like altered cholesterol balance, Alzheimer’s disease and cutaneous photosensitivity. Abnormal HFE protein resulting from the mutant HFE gene leads to formation of excess iron which has been postulated as likely mechanism for these diseases. Although there is evidence of iron overload in Africans, only few studies have explored possible genetic causes, and prevalence of rs1800562 is not known in West African population. Hence the need to determine the prevalence of rs1800562 in Nigeria using computational and wet laboratory approach. Methods/Case Report Details of rs1800562 were retrieved from Ensembl Genome Browser version 99. Severity of the consequences of this SNP on protein product was determined using bioinformatics tools including SIFT, Polyphen, Mutation Assessor, HOPE, I-mutant and MutPred2. Genotyping of rs1800562 was done In silico using restriction fragment length polymorphism (RFLP). Primer3plus was used for primer design, NCBI BLAST and SMS were used for primer validation. We used Webcutter 2.0 to determine suitable restriction enzymes. The genotyping was simulated using USCS virtual PCR and RestrictionMapper. Whole blood samples were obtained from 200 participants selected randomly from a pool of blood donors. DNA was extracted and flanking region of rs1800562 was amplified. The amplified product was digested by RSA1and fragments examined on agarose gel electrophoresis. Results (if a Case Study enter NA) The MAF was found to be 0.01 globally and 0.02 in Africa. In the two Nigerian population examined (Yoruba and Esan population), MAF was 0.00. Mutation Assessor and SIFT Polyphen consistently predicted the mutation to be of severe consequences. Analysis on HOPE, I-mutant and Mutpred2 revealed loss of protein stability, change in net charges affecting the HFE protein localization and its interaction with other proteins. All the participants in the wet laboratory analysis were homozygous for the wild type allele of rs1800562 (MAF=0). Conclusion This study confirmed the In silico prediction of the absence of rs1800562 in Nigeria. Future studies should focus on other SNPs of the HFE gene as well as other gene involved in iron metabolism.

Membrane Cholesterol Is a Critical Determinant for Hippocampal Neuronal Polarity.

Maintaining a normal cholesterol balance is crucial for the functioning of a healthy brain. Dysregulation in cholesterol metabolism and homeostasis in the brain have been correlated to various neurological disorders. The majority of previous studies in primary cultures focus on the role of cholesterol balance in neuronal development after polarity has been established. Here we have investigated how transient alteration of membrane lipids, specifically cholesterol, affects neuronal development and polarity in developing hippocampal neurons prior to polarity establishment, soon after initiation of neurite outgrowth. We observed that temporary cholesterol perturbation affects axonal and dendritic development differentially in an opposing manner. Transient membrane cholesterol deficiency increased neuronal population with a single neurite, simultaneously generating a second population of neurons with supernumerary axons. Brief replenishment of cholesterol immediately after cholesterol sequestering rescued neuronal development defects and restored polarity. The results showed a small window of cholesterol concentration to be complementing neurite outgrowth, polarity reestablishment, and in determining the normal neuronal morphology, emphasizing the critical role of precise membrane lipid balance in defining the neuronal architecture. Membrane cholesterol enhancement modified neurite outgrowth but did not significantly alter polarity. Cholesterol sequestering at later stages of development has shown to enhance neurite outgrowth, whereas distinct effects for neurite development and polarity were observed at early developmental stages, signifying the relevance of precise membrane cholesterol balance in altering neuronal physiology. Our results confirm cholesterol to be a key determinant for axo-dendritic specification and neuronal architecture and emphasize the possibility to reverse neuronal developmental defects caused by cholesterol deficiency by modulating membrane cholesterol during the early developmental stages.

Pcpe2, a Novel Extracellular Matrix Protein, Regulates Adipocyte SR-BI-Mediated High-Density Lipoprotein Uptake.

To investigate the role of adipocyte Pcpe2 (procollagen C-endopeptidase enhancer 2) in SR-BI (scavenger receptor class BI)-mediated HDL-C (high-density lipoprotein cholesterol) uptake and contributions to adipose lipid storage. Pcpe2, a glycoprotein devoid of intrinsic proteolytic activity, is believed to participate in extracellular protein-protein interactions, supporting SR-BI- mediated HDL-C uptake. In published studies, Pcpe2 deficiency increased the development of atherosclerosis by reducing SR-BI-mediated HDL-C catabolism, but the biological impact of this deficiency on adipocyte SR-BI-mediated HDL-C uptake is unknown. Differentiated cells from Ldlr-/-/Pcpe2-/- (Pcpe2-/-) mouse adipose tissue showed elevated SR-BI protein levels, but significantly reduced HDL-C uptake compared to Ldlr-/- (control) adipose tissue. SR-BI-mediated HDL-C uptake was restored by preincubation of cells with exogenous Pcpe2. In diet-fed mice lacking Pcpe2, significant reductions in visceral, subcutaneous, and brown adipose tissue mass were observed, despite elevations in plasma triglyceride and cholesterol concentrations. Significant positive correlations exist between adipose mass and Pcpe2 expression in both mice and humans. Overall, these findings reveal a novel and unexpected function for Pcpe2 in modulating SR-BI expression and function as it relates to adipose tissue expansion and cholesterol balance in both mice and humans.

Hepatocyte activity of the cholesterol sensor smoothened regulates cholesterol and bile acid homeostasis in mice

SummaryCellular cholesterol is regulated by at least two transcriptional mechanisms involving sterol-regulatory-element-binding proteins (SREBPs) and liver X receptors (LXRs). Although SREBP and LXR pathways are the predominant mechanisms that sense cholesterol in the endoplasmic reticulum and nucleus to alter sterol-regulated gene expression, evidence suggests cholesterol in plasma membrane can be sensed by proteins in the Hedgehog (Hh) pathway which regulate organ self-renewal and are a morphogenic driver during embryonic development. Cholesterol interacts with the G-protein-coupled receptor Smoothened (Smo), which impacts downstream Hh signaling. Although evidence suggests cholesterol influences Hh signaling, it is not known whether Smo-dependent sterol sensing impacts cholesterol homeostasis in vivo. We examined dietary-cholesterol-induced reorganization of whole-body sterol and bile acid (BA) homeostasis in adult mice with inducible hepatocyte-specific Smo deletion. These studies demonstrate Smo in hepatocytes plays a regulatory role in sensing and feedback regulation of cholesterol balance driven by excess dietary cholesterol.

SOAT1 is a new prognostic factor of colorectal cancer.

Colorectal cancer (CRC) is one of the most common malignant gastrointestinal cancers. Metastasis is the major leading cause of death in patients with CRC, and many patients treated with radical surgery were diagnosed with metastasis during follow-up. However, the underlying molecular mechanisms regulating CRC metastasis are still elusive. Sterol o-acyltransferase 1 (SOAT1) is a critical participant in maintaining intracellular cholesterol balance. Here, by analyzing the clinical specimens and in vitro cell line experiments, we evaluated the clinical relevance and role of SOAT1 in regulating CRC metastasis. The results revealed that SOAT1 was overexpressed in colon cancer tissues compared to peritumor tissues at mRNA and protein levels. High intratumor SOAT1 expression correlates to lymph node metastasis and indicates poor patient disease-free survival and overall survival. The silencing of SOAT1 strongly inhibited the migration and invasion ability of CRC tumor cells. These results demonstrated that SOAT1 was upregulated in colon cancer. Upregulation of SOAT1 expression may promote CRC progression by enhancing the migration and invasion ability of CRC. Our results indicate that targeting SOAT1 activity may be applied as a promising therapeutic strategy for preventing the metastasis of CRC after radical surgical treatment.

Contemporary aspects of cholesterol metabolism in cattle.

The literature review presents the current understanding of cholesterol metabolism occurring under physiological conditions. The homeostasis of cholesterol in the body is determined by its endogenous synthesis, the transition to the cell from plasma as part of low-densitylipoproteins( LDL), the release of their cells as part of high-density lipoproteins (HDL). The molecular-genetic mechanisms of regulation of cholesterol homeostasis are described in detail. The genes for cholesterol biosynthesis in major multicellular animals were inherited from their last common eukaryotic ancestor and are evolutionarily conserved for cholesterol biosynthesis. Non-coding variants of singlenucleotide polymorphisms can significantly contribute to the phenotypic variability of cholesterol, and missense variants that lead to the replacement of amino acids in proteins can have a significant effect on the phenotypic variability. The modern aspects of cholesterol homeostasis in cattle are formed and sufficiently fully presented. During absence of exogenous intake, the balance of cholesterol in cattle is maintained by endogenous synthesis, occurring mainly in the liver, the intake of lipoproteins, as well as reverse transport mechanisms. This review gives an idea that the stability of homeostasis can be achieved only with the complex interaction of all systems (transport, enzyme, receptor) involved in this process. The analysis of the latest scientific works concerning the problem of the content and regulation of cholesterol in cow’s milk is presented. Significant single-nucleotide polymorphisms localized in the ACAT2, LDLR, DGAT, and AGPAT1 genes involved in the exchange of cholesterol in the liver or its transport and associated with the level of cholesterol in milk are described. Part of the review is devoted to cholesterol deficiency syndrome in Holstein cattle (HCD). Modern data on the prevalence, molecular and genetic basis, clinical and laboratory manifestations of the syndrome are presented.

Abstract 1033: The anticancer compound avicin D targets lysosomal functions

Abstract This study investigates the mechanism by which avicins—plant-derived triterpenes with potent anticancer activity—alter lysosomal functions. The anticancer properties of avicins have been known for over two decades, yet the precise mechanism of action of avicins remains unknown. To elucidate their mechanism of action, we conducted a pooled CRISPR interference (CRISPRi) genetic screen in Jurkat T-cell leukemia cells treated with avicin D. Our screen revealed that the depletion of genes encoding lysosomal components protected cells from the drug's cytotoxic effects. Consistent with this finding, blocking lysosomal functions with chloroquine protected cells from avicins. Moreover, blocking the lysosomal cholesterol transporter NPC1 abolished avicin cytotoxicity, hinting that avicins—which resemble steroidogenic molecules—use the same cellular factors required for cholesterol transport. Together, these results suggest a causal relationship between a requirement for lysosomal functions and avicin cytotoxicity. The top hit whose depletion sensitized cells to avicin D was the endoplasmic reticulum (ER) stress sensor ATF6, which is a membrane-tethered transcription factor capable of detecting sphingolipid lipotoxicity in the ER membrane. Consistent with this result, recent observations indicate that avicins alter the cell's sphingolipid and cholesterol balance (1), suggesting that avicins induce ER stress by disrupting ER membrane homeostasis. Together, our results support a potential mechanism of action wherein avicins are pro-drugs activated in lysosomes and induce organelle stress by altering the cell's lipid balance. We are currently working on elucidating the molecular mechanisms by which avicins and their putative metabolic products disrupt organelle homeostasis. We anticipate that our study will reveal the molecular circuitry that controls the cell's response to avicins and may open new avenues for therapeutic intervention in cancer. 1. Garrido CM, Henkels KM, Rehl KM, Liang H, Zhou Y, Gutterman JU, Cho K-J. Avicin G is a potent sphingomyelinase inhibitor and blocks oncogenic K- and H-Ras signaling. PMC7272413 Citation Format: Friederike Braig, Jordan U. Gutterman, Diego Acosta-Alvear. The anticancer compound avicin D targets lysosomal functions [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1033.

LXR directly regulates glycosphingolipid synthesis and affects human CD4+ T cell function

The liver X receptor (LXR) is a key transcriptional regulator of cholesterol, fatty acid, and phospholipid metabolism. Dynamic remodeling of immunometabolic pathways, including lipid metabolism, is a crucial step in T cell activation. Here, we explored the role of LXR-regulated metabolic processes in primary human CD4+ T cells and their role in controlling plasma membrane lipids (glycosphingolipids and cholesterol), which strongly influence T cell immune signaling and function. Crucially, we identified the glycosphingolipid biosynthesis enzyme glucosylceramide synthase as a direct transcriptional LXR target. LXR activation by agonist GW3965 or endogenous oxysterol ligands significantly altered the glycosphingolipid:cholesterol balance in the plasma membrane by increasing glycosphingolipid levels and reducing cholesterol. Consequently, LXR activation lowered plasma membrane lipid order (stability), and an LXR antagonist could block this effect. LXR stimulation also reduced lipid order at the immune synapse and accelerated activation of proximal T cell signaling molecules. Ultimately, LXR activation dampened proinflammatory T cell function. Finally, compared with responder T cells, regulatory T cells had a distinct pattern of LXR target gene expression corresponding to reduced lipid order. This suggests LXR-driven lipid metabolism could contribute to functional specialization of these T cell subsets. Overall, we report a mode of action for LXR in T cells involving the regulation of glycosphingolipid and cholesterol metabolism and demonstrate its relevance in modulating T cell function.

Cholesterol loading suppresses the atheroinflammatory gene polarization of human macrophages induced by colony stimulating factors

In atherosclerotic lesions, blood-derived monocytes differentiate into distinct macrophage subpopulations, and further into cholesterol-filled foam cells under a complex milieu of cytokines, which also contains macrophage-colony stimulating factor (M-CSF) and granulocyte–macrophage-colony stimulating factor (GM-CSF). Here we generated human macrophages in the presence of either M-CSF or GM-CSF to obtain M-MØ and GM-MØ, respectively. The macrophages were converted into cholesterol-loaded foam cells by incubating them with acetyl-LDL, and their atheroinflammatory gene expression profiles were then assessed. Compared with GM-MØ, the M-MØ expressed higher levels of CD36, SRA1, and ACAT1, and also exhibited a greater ability to take up acetyl-LDL, esterify cholesterol, and become converted to foam cells. M-MØ foam cells expressed higher levels of ABCA1 and ABCG1, and, correspondingly, exhibited higher rates of cholesterol efflux to apoA-I and HDL2. Cholesterol loading of M-MØ strongly suppressed the high baseline expression of CCL2, whereas in GM-MØ the low baseline expression CCL2 remained unchanged during cholesterol loading. The expression of TNFA, IL1B, and CXCL8 were reduced in LPS-activated macrophage foam cells of either subtype. In summary, cholesterol loading converged the CSF-dependent expression of key genes related to intracellular cholesterol balance and inflammation. These findings suggest that transformation of CSF-polarized macrophages into foam cells may reduce their atheroinflammatory potential in atherogenesis.