Plasma lipidomic analysis of sphingolipids in patients with large artery atherosclerosis cerebrovascular disease and cerebral small vessel disease

A proposed biomarker for human citric acid ester (CAE) exposure, and the potential disturbance on human lipid metabolism

Citric acid esters (CAEs), as one class of important alternative plasticizers, have been proven to be ubiquitous in the environments, leading to an increasing concern regarding their potential health risk to humans. However, information regarding the biomarkers for human CAE biomonitoring is currently unknown. In the present study, we investigated the metabolism characteristics of CAEs by use of in vitro rat liver microsomes (RLMs) and in vivo mice. We observed that CAEs would undergo a rapid metabolism in both in vitro and in vivo conditions, implying that parent CAEs could be not suitable for biomonitoring of human CAE exposure. By use of high-resolution Orbitrap mass spectrometry (MS), ten molecules were tentatively identified as CAE potential metabolites on the basis of their MS and MS/MS characteristics, and CAEs could be metabolized via multiple pathways, i.e. hydrolyzation, hydroxylation, O-dealkylation. Further MS screening in human serum samples demonstrated that most of parent CAEs were not detectable, whereas numerous CAE metabolites were detected in the same batch of analyzed samples. Especially, one of metabolites of tributyl citrate (named with TBC-M1), exhibited a high detection frequency of 73.3%. By use of TBC-M1 as the biomarker of human CAE exposure, alteration of lipid metabolism was further examined in human serum. Interestingly, we observed statistically significant correlations between TBC-M1 levels and population characteristics (i.e., age, BMI, and drinking). Beyond that, we also observed statistically significant correlation between levels of TBC-M1 and lipid molecules (phosphatidylinositol (18:0/20:4) and sphingomyelin (d34:1)). Collectively, this study underscored the property of rapid metabolism of CAEs in exposed organism, and proposed a potential biomarker that could be greatly helpful for further investigating the human CAE exposure and understanding their potential health risks.

The Blood Plasma Lipidomic Profile in Atherosclerosis of the Brachiocephalic Arteries

According to the World Health Organization, ischemic stroke is the second leading cause of death in the world. Frequently, it is caused by brachiocephalic artery (BCA) atherosclerosis. Timely detection of atherosclerosis and its unstable course can allow for a timely response to potentially dangerous changes and reduce the risk of vascular complications. Omics technologies allow us to identify new biomarkers that we can use in diagnosing diseases. This research included 90 blood plasma samples. The study group comprised 52 patients with severe atherosclerotic lesions BCA, and the control group comprised 38 patients with no BCA atherosclerosis. Targeted and panoramic lipidomic profiling of their blood plasma was carried out. There was a statistically significant difference (p < 0.05) in the values of the indices saturated fatty acids (FAs), unsaturated FAs, monounsaturated FAs, omega-3, and omega-6. Based on the results on the blood plasma lipidome, we formed models that have a fairly good ability to determine atherosclerotic lesions of the brachiocephalic arteries, as well as a model for identifying unstable atherosclerotic plaques. According only to the panoramic lipidome data, divided into groups according to stable and unstable atherosclerotic plaques, a significant difference was taken into account: p value < 0.05 and abs (fold change) > 2. Unfortunately, we did not observe significant differences according to the established plasma panoramic lipidome criteria between patients with stable and unstable plaques. Omics technologies allow us to obtain data about any changes in the body. According to our data, statistically significant differences in lipidomic profiling were obtained when comparing groups with or without BCA atherosclerosis.

Metabolomics and lipidomics combined with serum pharmacochemistry uncover the potential mechanism of Huang-Lian-Jie-Du decoction alleviates atherosclerosis in ApoE-/- mice

ETHNOPHARMACOLOGICAL RELEVANCE

Atherosclerosis (AS) is one of the main cardiovascular diseases (CVDs) leading to an increase in global mortality, and its key pathological features are lipid accumulation and oxidative stress. Huang-Lian-Jie-Du decoction (HLJDD), a representative formula for clearing heat and detoxifying, has been shown to reduce aortic lipid plaque and improve AS. However, multiple components and multiple targets of HLJDD pose a challenge in comprehending its comprehensive mechanism in the treatment of AS.

AIM OF THE STUDY

This study was designed to illustrate the anti-AS mechanisms of HLJDD in an apolipoprotein E-deficient (ApoE-/-) mouse model from a metabolic perspective.

MATERIALS AND METHODS

ApoE-/- mice were kept on a high-fat diet (HFD) to induce AS. Serum total cholesterol (TC), total triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) levels were determined to evaluate the influence of HLJDD on dyslipidemia. Oil red O was used to stain mouse aortic lipid plaques, and hematoxylin and eosin (HE) staining was used to assess the pathological changes in the aortic roots. Metabolomics and lipidomics combined with serum pharmacochemistry were performed to research the HLJDD mechanism of alleviating AS.

RESULTS

In this study, HLJDD treatment improved serum biochemical levels and histopathological conditions in AS mice. A total of 6 metabolic pathways (arginine biosynthesis, glycerophospholipid, sphingolipid, arachidonic acid, linoleic acid, and glycerolipid metabolism) related to 25 metabolic biomarkers and 41 lipid biomarkers were clarified, and 22 prototype components migrating to blood were identified after oral administration of HLJDD.

CONCLUSION

HLJDD improved AS induced by HFD in ApoE-/- mice. The effects of HLJDD were mainly attributed to regulating lipid metabolism by regulating the metabolic pathways of glycerophospholipids, sphingolipids, arachidonic acid, linoleic acid, and glycerolipids and reducing the levels of oxidative stress by upregulating arginine biosynthesis.

Evaluating the Metabolic Basis of α-Gal A mRNA Therapy for Fabry Disease

mRNA injection-based protein supplementation has emerged as a feasible treatment for Fabry disease. However, whether the introduction of LNP-encapsulated mRNA results in the alteration of metabolomics in an in vivo system remains largely unknown. In the present study, α-galactosidase A (α-Gal A) mRNA was generated and injected into the Fabry disease mouse model. The α-Gal A protein was successfully expressed. The level of globotriaosylsphingosine (Lyso-Gb3), a biomarker for Fabry disease, as well as pro-inflammatory cytokines such as nuclear factor kappa-B (NF-κB), interleukin 6 (IL-6), and tumor necrosis factor-α (TNF-α), were greatly decreased compared to the untreated control, indicating the therapeutic outcome of the mRNA drug. Metabolomics analysis found that the level of 20 metabolites was significantly altered in the plasma of mRNA-injected mice. These compounds are primarily enriched in the arachidonic acid metabolism, alanine, aspartate and glutamate metabolism, and glycolysis/gluconeogenesis pathways. Arachidonic acid and 5-hydroxyeicosatetraenoic acid (5-HETE), both of which are important components in the eicosanoid pathway and related to inflammation response, were significantly increased in the injected mice, possibly due to the presence of lipid nanoparticles. Moreover, mRNA can effectively alter the level of metabolites in the amino acid and energy metabolic pathways that are commonly found to be suppressed in Fabry disease. Taken together, the present study demonstrated that in addition to supplementing the deficient α-Gal A protein, the mRNA-based therapeutic agent can also affect levels of metabolites that may help in the recovery of metabolic homeostasis in the full body system.

Lipidomic Approaches in Common and Rare Cerebrovascular Diseases: The Discovery of Unconventional Lipids as Novel Biomarkers

Stroke remains a major cause of death and disability worldwide. Identifying new circulating biomarkers able to distinguish and monitor common and rare cerebrovascular diseases that lead to stroke is of great importance. Biomarkers provide complementary information that may improve diagnosis, prognosis and prediction of progression as well. Furthermore, biomarkers can contribute to filling the gap in knowledge concerning the underlying disease mechanisms by pointing out novel potential therapeutic targets for personalized medicine. If many "conventional" lipid biomarkers are already known to exert a relevant role in cerebrovascular diseases, the aim of our study is to review novel "unconventional" lipid biomarkers that have been recently identified in common and rare cerebrovascular disorders using novel, cutting-edge lipidomic approaches.

Ceramide in cerebrovascular diseases

Ceramide, a bioactive sphingolipid, serves as an important second messenger in cell signal transduction. Under stressful conditions, it can be generated from de novo synthesis, sphingomyelin hydrolysis, and/or the salvage pathway. The brain is rich in lipids, and abnormal lipid levels are associated with a variety of brain disorders. Cerebrovascular diseases, which are mainly caused by abnormal cerebral blood flow and secondary neurological injury, are the leading causes of death and disability worldwide. There is a growing body of evidence for a close connection between elevated ceramide levels and cerebrovascular diseases, especially stroke and cerebral small vessel disease (CSVD). The increased ceramide has broad effects on different types of brain cells, including endothelial cells, microglia, and neurons. Therefore, strategies that reduce ceramide synthesis, such as modifying sphingomyelinase activity or the rate-limiting enzyme of the de novo synthesis pathway, serine palmitoyltransferase, may represent novel and promising therapeutic approaches to prevent or treat cerebrovascular injury-related diseases.

The Dark Side of Sphingolipids: Searching for Potential Cardiovascular Biomarkers

Cardiovascular diseases (CVDs) are the leading cause of death and illness in Europe and worldwide, responsible for a staggering 47% of deaths in Europe. Over the past few years, there has been increasing evidence pointing to bioactive sphingolipids as drivers of CVDs. Among them, most studies place emphasis on the cardiovascular effect of ceramides and sphingosine-1-phosphate (S1P), reporting correlation between their aberrant expression and CVD risk factors. In experimental in vivo models, pharmacological inhibition of de novo ceramide synthesis averts the development of diabetes, atherosclerosis, hypertension and heart failure. In humans, levels of circulating sphingolipids have been suggested as prognostic indicators for a broad spectrum of diseases. This article provides a comprehensive review of sphingolipids' contribution to cardiovascular, cerebrovascular and metabolic diseases, focusing on the latest experimental and clinical findings. Cumulatively, these studies indicate that monitoring sphingolipid level alterations could allow for better assessment of cardiovascular disease progression and/or severity, and also suggest them as a potential target for future therapeutic intervention. Some approaches may include the down-regulation of specific sphingolipid species levels in the circulation, by inhibiting critical enzymes that catalyze ceramide metabolism, such as ceramidases, sphingomyelinases and sphingosine kinases. Therefore, manipulation of the sphingolipid pathway may be a promising strategy for the treatment of cardio- and cerebrovascular diseases.

Vascular lipidomics analysis reveales increased levels of phosphocholine and lysophosphocholine in atherosclerotic mice

OBJECTIVE

Atherosclerosis (AS) is the major cause of cardiovascular disease, and dyslipidemia is a principal determinant of the initiation and progression of AS. Numerous works have analyzed the lipid signature of blood, but scarce information on the lipidome of vascular tissue is available. This study investigated the lipid profile in the aorta of ApoE^-/- mice.

METHOD

ApoE^-/- mice were randomly divided into two groups: (1) the normal diet (ND) group and (2) the high-fat diet (HFD) group. After feeding for 8 weeks, the plasma low-density lipoprotein (LDL), total cholesterol (TC), and triglyceride (TGs) levels were measured. UHPLC-Q Exactive plus MS was used to assess the lipid profile using both positive and negative ionization modes.

RESULTS

LDL and TC levels were significantly increased in HFD mice, and lipid deposition, plaque area and collagen fiber levels were increased in HFD group. In addition, a total of 131 differential lipids were characterized, including 57 lipids with levels that were increased in the HFD group and 74 with levels that were decreased. Further analysis revealed that the levels of several differentially expressed phosphocholines (PCs) and lysophosphocholines (LPCs) were significantly increased. These PCs included PC (38:3), PC (36:4), PC (36:3), PC (36:2), PC (36:1), PC (34:1e), PC (34:1), PC (32:1), PC (18:0/18:1), and PC (38:5), and the LPCs included LPC (18:1), LPC (18:0) and LPC (16:0).

CONCLUSION

Our findings indicate the presence of a comprehensive lipid profile in the vascular tissue of atherosclerotic mice, particularly involving PC and LPC, which exhibited significantly increased levels in AS.

Alterations in Plasma Lipidomic Profiles in Adult Patients with Schizophrenia and Major Depressive Disorder

Background and Objectives: Lipidomics is a pivotal tool for investigating the pathogenesis of mental disorders. However, studies qualitatively and quantitatively analyzing peripheral lipids in adult patients with schizophrenia (SCZ) and major depressive disorder (MDD) are limited. Moreover, there are no studies comparing the lipid profiles in these patient populations. Materials and Method: Lipidomic data for plasma samples from sex- and age-matched patients with SCZ or MDD and healthy controls (HC) were obtained and analyzed by liquid chromatography-mass spectrometry (LC-MS). Results: We observed changes in lipid composition in patients with MDD and SCZ, with more significant alterations in those with SCZ. In addition, a potential diagnostic panel comprising 103 lipid species and another diagnostic panel comprising 111 lipid species could distinguish SCZ from HC (AUC = 0.953) or SCZ from MDD (AUC = 0.920) were identified, respectively. Conclusions: This study provides an increased understanding of dysfunctional lipid composition in the plasma of adult patients with SCZ or MDD, which may lay the foundation for identifying novel clinical diagnostic methods for these disorders.

Correlation of acetyl-coenzyme A carboxylase 1 with Th17 and Th1 cells, serving as a potential prognostic biomarker for acute ischemic stroke patients

Background

Acetyl‐coenzyme A carboxylase 1 (ACC1) regulates lipid homeostasis, T helper (Th) cell differentiation, oxidative stress, inflammation response, and neurological process, engaging in acute ischemic stroke (AIS) pathogenesis, while its clinical utility in AIS is unclear. Hence, this study intended to explore the correlation among blood ACC1, Th17, and Th1 cells, and ACC1’s potency as a prognostic biomarker for AIS management.

Methods

ACC1 in peripheral blood mononuclear cells (PBMCs) of 160 AIS patients and 30 controls were determined using RT‐qPCR; blood Th17 and Th1 cells in AIS patients were quantified by flow cytometry.

Results

ACC1 was increased in AIS patients compared with controls (median (interquartile range): 2.540 (1.753–3.548) vs. 0.980 (0.655–1.743), p < 0.001), which exhibited a good value to reflect AIS risk with the area under the curve of 0.872 (95% CI: 0.805–0.939). Moreover, ACC1 was positively linked with Th17 (r = 0.374, p < 0.001) and Th1 (r = 0.178, p = 0.024) cells in AIS patients. Additionally, ACC1 (r = 0.328, p < 0.001), Th17 (r = 0.272, p = 0.001), and Th1 cells (r = 0.195, p = 0.014) were positively associated with the National Institutes of Health Stroke Scale score in AIS patients. ACC1 high vs. low (p = 0.038) and Th17 high vs. low (p = 0.026) were related to shortened recurrence‐free survival (RFS) in AIS patients, while Th1 cells (p = 0.179) were not correlated with RFS. Whereas ACC1 (p = 0.248), Th17 (p = 0.079), and Th1 cells (p = 0.130) were not linked with overall survival (OS) in AIS patients.

Conclusion

Circulating ACC1 overexpression correlates with increased Th17, Th1 cells, NIHSS score, and shortened RFS in AIS patients.

Need for a Paradigm Shift in the Treatment of Ischemic Stroke: The Blood-Brain Barrier

Blood-brain barrier (BBB) integrity is essential to maintaining brain health. Aging-related alterations could lead to chronic progressive leakiness of the BBB, which is directly correlated with cerebrovascular diseases. Indeed, the BBB breakdown during acute ischemic stroke is critical. It remains unclear, however, whether BBB dysfunction is one of the first events that leads to brain disease or a down-stream consequence. This review will focus on the BBB dysfunction associated with cerebrovascular disease. An added difficulty is its association with the deleterious or reparative effect, which depends on the stroke phase. We will first outline the BBB structure and function. Then, we will focus on the spatiotemporal chronic, slow, and progressive BBB alteration related to ischemic stroke. Finally, we will propose a new perspective on preventive therapeutic strategies associated with brain aging based on targeting specific components of the BBB. Understanding BBB age-evolutions will be beneficial for new drug development and the identification of the best performance window times. This could have a direct impact on clinical translation and personalised medicine.

Metabolomic profiling in small vessel disease identifies multiple associations with disease severity

Cerebral small vessel disease is a major cause of vascular cognitive impairment and dementia. There are few treatments, largely reflecting limited understanding of the underlying pathophysiology. Metabolomics can be used to identify novel risk factors to better understand pathogenesis and to predict disease progression and severity. We analysed data from 624 patients with symptomatic cerebral small vessel disease from two prospective cohort studies. Serum samples were collected at baseline and patients underwent MRI scans and cognitive testing at regular intervals with up to 14 years of follow-up. Using ultra-performance liquid chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy, we obtained metabolic and lipidomic profiles from 369 annotated metabolites and 54 764 unannotated features and examined their association with respect to disease severity, assessed using MRI small vessel disease markers, cognition and future risk of all-cause dementia. Our analysis identified 28 metabolites that were significantly associated with small vessel disease imaging markers and cognition. Decreased levels of multiple glycerophospholipids and sphingolipids were associated with increased small vessel disease load as evidenced by higher white matter hyperintensity volume, lower mean diffusivity normalized peak height, greater brain atrophy and impaired cognition. Higher levels of creatine, FA(18:2(OH)) and SM(d18:2/24:1) were associated with increased lacune count, higher white matter hyperintensity volume and impaired cognition. Lower baseline levels of carnitines and creatinine were associated with higher annualized change in peak width of skeletonized mean diffusivity, and 25 metabolites, including lipoprotein subclasses, amino acids and xenobiotics, were associated with future dementia incidence. Our results show multiple distinct metabolic signatures that are associated with imaging markers of small vessel disease, cognition and conversion to dementia. Further research should assess causality and the use of metabolomic screening to improve the ability to predict future disease severity and dementia risk in small vessel disease. The metabolomic profiles may also provide novel insights into disease pathogenesis and help identify novel treatment approaches.

Bias caused by incomplete metabolite extraction and matrix effect: Evaluation of critical factors for plasma sample preparation prior to metabolomics

Metabolomics is an omics strategy to study the metabolite alteration in the biological system. Unbiased observation of the metabolite level is essential for targeted metabolite quantification and untargeted metabolic profiling. State-of-the-art instruments and versatile tools have been developed for accurate observation of metabolic alterations in various studies. Several analytical pitfalls, such as sample overloading and signal-saturation-induced bias, have been revealed and addressed. In this study, we proposed incomplete-metabolite-extraction-caused bias is also an important issue that results in biased observation when performing metabolomics. In the demonstration example, numerous metabolites exhibited no significant difference between extracted plasma samples with different plasma contents, which is attributed to incomplete-metabolite-extraction-caused bias and matrix effect. Matrix effect is a well-known factor that result in biased observation, it can be reduced by sample dilution and compensated by using stable isotope labelled internal standards. The detection of metabolite signals in the following consecutive extractions provided further evidence of incomplete metabolite extraction. The completeness of metabolite extraction is crucial for unbiased observation of metabolic profile changes. To address this issue, we optimized the extraction time and methanol volume to reduce the incomplete-metabolite-extraction-caused bias and evaluated the metabolite signals in consecutive extractions. Methanol extraction performed with a plasma-to-methanol ratio of 1:14 resulted in metabolite responses of less than 18.1 % in the second extractions observed by metabolomic profiling. Finally, the optimized sample preparation procedure and untargeted profiling platform were applied to detect metabolite alterations associated with patients with cerebrovascular diseases and several features with significant difference were successfully identified. This study revealed and evaluated the bias caused by incomplete metabolite extraction and matrix effect in the commonly used methanol extraction method for human plasma sample preparation for metabolomics. We anticipate the proposed metabolite extraction evaluation method could benefit more clinical and biological metabolomics studies.

Involvement of Ceramide Metabolism in Cerebral Ischemia

Ischemic stroke, caused by the interruption of blood flow to the brain and subsequent neuronal death, represents one of the main causes of disability in worldwide. Although reperfusion therapies have shown efficacy in a limited number of patients with acute ischemic stroke, neuroprotective drugs and recovery strategies have been widely assessed, but none of them have been successful in clinical practice. Therefore, the search for new therapeutic approaches is still necessary. Sphingolipids consist of a family of lipidic molecules with both structural and cell signaling functions. Regulation of sphingolipid metabolism is crucial for cell fate and homeostasis in the body. Different works have emphasized the implication of its metabolism in different pathologies, such as diabetes, cancer, neurodegeneration, or atherosclerosis. Other studies have shown its implication in the risk of suffering a stroke and its progression. This review will highlight the implications of sphingolipid metabolism enzymes in acute ischemic stroke.

LC-MS lipidomics of renal biopsies for the diagnosis of Fabry disease

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Fabry is an X-linked lysosomal storage disease with deficiency in α-galactosidase.

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This deficiency results in the accumulation of glycosphinogolipids.

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Diagnosis is often made by analysis of globotriaosylceramide in fluids and tissues.

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Fabry is often misdiagnosed in female patients due to residual enzyme activity.

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Lipidomics by LC-HRMS enables identification of new biomarkers in Fabry.

Introduction

Lipidomics analysis or lipid profiling is a system-based analysis of all lipids in a sample to provide a comprehensive understanding of lipids within a biological system. In the last few years, lipidomics has made it possible to better understand the metabolic processes associated with several rare disorders and proved to be a powerful tool for their clinical investigation. Fabry disease is a rare X-linked lysosomal storage disorder (LSD) caused by a deficiency in α-galactosidase A (α-GAL A). This deficiency results in the progressive accumulation of glycosphingolipids, mostly globotriaosylceramide (Gb₃), globotriaosylsphingosine (lyso-Gb₃), as well as galabiosylceramide (Ga₂) and their isoforms/analogs in the vascular endothelium, nerves, cardiomyocytes, renal glomerular podocytes, and biological fluids.

Objectives

The primary objective of this study was to evaluate lipidomic signatures in renal biopsies to help understand variations in Fabry disease markers that could be used in future diagnostic tests.

Methods

Lipidomic analysis was performed by ultra-high pressure liquid chromatography-high-resolution mass spectrometry (UHPLC-HRMS) on kidney biopsies that were left over after clinical pathology analysis to diagnose Fabry disease.

Results

We employed UHPLC-HRMS lipidomics analysis on the renal biopsy of a patient suspicious for Fabry disease. Our result confirmed α-GAL A enzyme activity declined in this patient since a Ga2-related lipid biomarker was substantially higher in the patient's renal tissue biopsy compared with two controls. This suggests this patient has a type of LSD that could be non-classical Fabry disease.

Conclusion

This study shows that lipidomics analysis is a valuable tool for rare disorder diagnosis, which can be conducted on leftover tissue samples without disrupting normal patient care.

Changes in plasma sphingolipid levels against the background of lipid-lowering therapy in patients with premature atherosclerosis

Lipid-lowering drugs affect standard lipoproteins. However, we have no knowledge of changes in other plasma lipids upon treatment. The study was aimed to assess the dynamic changes in cholesterol, high- and low-density lipoproteins (HDL and LDL), triglycerides, and sphingolipids against the background of lipidlowering therapy in patients with premature coronary artery disease, atherosclerosis and hypercholesterolemia. A total of 18 patients were enrolled (the average age was 53 ± 6.7 years): in group 1, six patients received starting statin doses; group 2 included six patients, who failed to achieve LDL target levels against the background of treatment with starting statin doses, and received escalated statin doses; seven patients in group 3 failed to achieve LDL target levels against the background of treatment with maximum tolerated doses of statins and ezetimibe, and received alirocumab. Sphingolipid levels were assessed by mass spectrometry. In group 1, the decreased levels of ceramide Cer 14:1 (p = 0.046) and sphingomyelins SM 22:1, SM 22:0, SM 24:0 (p = 0.028) were observed. There were no significant changes in the levels of total cholesterol, LDL-C, HDL-C, and triglycerides. In group 2, the significantly decreased levels of total cholesterol (p = 0.028), LDL (p = 0.043), sphingomyelins SM 18:1, SM 24:1 and SM 26:1, and ceramide Cer 16:1 (p = 0.028) were observed. The level of Cer 22:1 significantly increased (p = 0.028). In group 3, total cholesterol decreased by 36.2%, and LDL-C (p = 0.018) decreased by 60.1% compared to baseline (ΔLDL-C = –2.67 ± 3.12); the elevated levels of ceramide Cer 22:1 (p = 0.028) were observed. It has been shown, that decreased sphingomyelin levels are associated with statin therapy and correlate with decreased levels of LDL-C. No significant dynamic changes in ceramides and ceramide risk against the background of statin therapy were observed, however, PCSK9 inhibitor added to therapy reduced the Cer 16:0/24:0 ratio.

The noncanonical chronicles: Emerging roles of sphingolipid structural variants

Sphingolipids (SPs) are structurally diverse and represent one of the most quantitatively abundant classes of lipids in mammalian cells. In addition to their structural roles, many SP species are known to be bioactive mediators of essential cellular processes. Historically, studies have focused on SP species that contain the canonical 18‑carbon, mono-unsaturated sphingoid backbone. However, increasingly sensitive analytical technologies, driven by advances in mass spectrometry, have facilitated the identification of previously under-appreciated, molecularly distinct SP species. Many of these less abundant species contain noncanonical backbones. Interestingly, a growing number of studies have identified clinical associations between these noncanonical SPs and disease, suggesting that there is functional significance to the alteration of SP backbone structure. For example, associations have been found between SP chain length and cardiovascular disease, pain, diabetes, and dementia. This review will provide an overview of the processes that are known to regulate noncanonical SP accumulation, describe the clinical correlations reported for these molecules, and review the experimental evidence for the potential functional implications of their dysregulation. It is likely that further scrutiny of noncanonical SPs may provide new insight into pathophysiological processes, serve as useful biomarkers for disease, and lead to the design of novel therapeutic strategies.

LncRNA CDKN2B-AS1 Promotes Cell Viability, Migration, and Invasion of Hepatocellular Carcinoma via Sponging miR-424-5p

Objective

Hepatocellular carcinoma (HCC) results in high mortality and metastasis. In this study, the effects of long non-coding RNA (lncRNA) CDKN2B-AS1 on the progression of HCC were investigated.

Materials and Methods

LncRNA CDKN2B-AS1 expression of HCC cancer and adjacent tissues, and HCC cells were detected. Subsequently, CDKN2B-AS1 was overexpressed and silenced in HCC cells to observe the effects of CDKN2B-AS1 on the cell viability, migration, invasion, and epithelial–mesenchymal transition (EMT) of HCC cells by performing cell counting kit-8 (CCK-8), wound-healing, Transwell, and Western blot. The target gene of CDKN2B-AS1 was predicted and verified to be miR-424-5p, whose expression in HCC cells with up- or down-regulation of CDKN2B-AS1 expression was determined. Moreover, the effects of miR-424-5p on cell viability, migration, and invasion and EMT of HCC cells were investigated with miR-424-5p up-regulation or down-regulation, together with overexpression or silencing of CDKN2B-AS1.

Results

CDKN2B-AS1 expression was increased in HCC tissues and cells. Silencing of CDKN2B-AS1 suppressed cell viability, migration, invasion, and EMT, while overexpression of CDKN2B-AS1 produced the opposite results. Furthermore, CDKN2B-AS1 was predicted and verified to target miR-424-5p and was confirmed to negatively modulate miR-424-5p expression. Moreover, overexpression of miR-424-5p partially suppressed the previously high cell viability, migration, and invasion, and activated EMT resulted from up-regulation of CDKN2B-AS1, while silencing of miR-424-5p elevated the cellular processes inhibited by silencing the expression of CDKN2B-AS1.

Conclusion

The present study revealed that high-expressed CDKN2B-AS1 may associate with the progression of HCC by affecting the cell viability, migration, invasion, and EMT of HCC cells by negatively regulating miR-424-5p.