Role of Stearoyl-CoA Desaturase 1 in Cardiovascular Physiology

Nuclear Magnetic Resonance (NMR)-Based Lipidomics Reveal the Association of Altered Red Blood Cell (RBC) Membrane Lipidome with the Presence and the Severity of Coronary Artery Stenosis

Coronary heart disease (CHD) is the leading cause of morbidity and mortality worldwide despite significant improvements in diagnostic modalities. Emerging evidence suggests that erythrocytes, or red blood cells (RBCs), are one of the most important contributors to the events implicated in atherosclerosis, although the molecular mechanisms behind it are under investigation. We used NMR-based lipidomic technology to investigate the RBC lipidome in patients with CHD compared to those with normal coronary arteries (NCAs), all angiographically documented, and its correlation with coronary artery stenosis. Targeted and untargeted lipidomic analysis revealed that CHD patients presented significant lipid alterations in the RBC membrane, characterized by higher cholesterol, sphingolipids, saturated and monounsaturated fatty acids, lower phospholipids (glycerophospholipids and ether glycerolipids), and unsaturated and polyunsaturated fatty acids. These aberrations gradually distinguish the three subgroups of patients with mild, moderate, and severe coronary stenosis, potentially indicating their non-negligible involvement in the onset and progression of atherosclerosis. The comprehensive analysis of RBC-membrane-derived lipids with omics approaches could unravel specific lipid abnormalities taking place at the silent subclinical stage of atherosclerosis and could have the potential to identify patients with subtle, but still proatherogenic, abnormalities that may confer a higher risk for the development of CHD.

Association between Serum Fatty Acids Profile and MetScore in Women with Severe Obesity

BACKGROUND

Metabolic syndrome (MetS) is a set of conditions associated with an increased cardiovascular risk. Several serum fatty acids (FAs) seem to play an essential role in the development of cardiometabolic diseases and mortality. Thus, it is imperative to explore the impact of FAs on MetS parameters, using an early MetS screening tool such as MetScore, which is readily available in clinical practice.

AIM

The aim of this study was to assess the potential correlation between serum FAs and cardiovascular risk using a MetScore.

METHODS

This cross-sectional study involved 41 women with severe obesity. The MetScore was calculated, and participants were categorized into high- and low-cardiovascular-risk groups based on the median MetScore value. Gas chromatography was used to quantify serum FAs. Generalized Linear Models were used to compare group means. The association was assessed through simple logistic regression, and an adjusted logistic regression was conducted to validate the association between Metscore and serum FAs.

RESULTS

The high-cardiovascular-risk group exhibited elevated values of HOMA-IR, palmitic, oleic, cis-vaccenic, and monounsaturated fatty acids, as well as the SCD-18C, indicating a heightened cardiovascular risk. Conversely, HDL-c, QUICK, gamma-linolenic, and eicosatetraenoic fatty acids showed lower values compared to the low-risk group.

CONCLUSIONS

Women with severe obesity and high cardiovascular risk have lower values of some omega-3 and omega-6 FAs, considered cardioprotective and anti-inflammatory, and have higher lipogenic activity and FAs, correlated with high cardiovascular risk. These findings emphasize the need to address lipid metabolism in this population as a therapeutic target to reduce cardiovascular risk. Future research should explore clinical interventions that modulate fatty acid metabolism to mitigate cardiometabolic complications.

An insight into advances and challenges in the development of potential stearoyl Co-A desaturase 1 inhibitors

Stearoyl-CoA desaturase 1 (SCD1) is one of the key enzymes involved in lipid metabolism, plays a vital role in the synthesis of monounsaturated fatty acids (MUFAs) from saturated fatty acids (SFAs). Due to its promising therapeutic potential in treating metabolic disorders, cancers, and skin diseases there is an increasing interest in the development of novel inhibitors against SCD1. This review comprehensively explores the evolution of potential SCD1 inhibitors, focusing on systemic and liver-targeted inhibitors and discusses their structure-activity relationship (SAR) pattern. Among the various small molecules reported, natural products like sterculic acid have emerged as significant SCD1 inhibitors, highlighting the potential of naturally derived compounds in therapeutic development. This review also addresses the challenges in optimizing pharmacokinetic properties and reducing adverse effects, providing insights into the future directions for the development of potential novel SCD1 inhibitors with maximum therapeutic effect and minimum side effects.

Sweet pepper extract reduces fat storage in Caenorhabditis elegans by SREBP-SCD axis based on multiomics analysis

Sweet pepper, a globally commercialized horticultural crop, has been demonstrated to impede fat accumulation, but its mechanism remains incompletely understood. This study was designed to explore the potential mechanism of sweet pepper in reducing fat accumulation in Caenorhabditis elegans through RNA-seq and metabolome analysis. A total of 22 metabolites were identified from sweet pepper by UHPLC-ESI-TOF-MS analysis. In vivo, sweet pepper significantly inhibited α-glucosidase activity and reduced the levels of glucose, triglycerides (TG), total cholesterol (TC), and the area stained with oil red O. Additionally, it increased body length and the number of head swings in C. elegans compared to the control group. The KEGG enrichment analysis revealed significant enrichment of the biosynthesis of unsaturated fatty acids signaling pathway among the differentially expressed genes and metabolites. Furthermore, the mRNA levels of sterol regulatory element-binding proteins (SREBPs) ortholog SBP-1, as well as the stearyl CoA desaturase-1 (SCD1), including fat-5, fat-6, and fat-7, were significantly decreased after treatment with sweet pepper. Collectively, sweet pepper effectively reduces fat accumulation, which is probably related to downregulating the SREBP-SCD axis, offering new insights for future functional food development.

Effect of virgin olive oil as spreadable preparation on atherosclerosis compared to dairy butter in Apoe-deficient mice

Olive oil is the main source of lipid energy in the Mediterranean diet and there is strong evidence of its health benefits. The effect of extra virgin olive oil (EVOO) in the form of a preparation of spreadable virgin olive oil (S-VO) on the progression of atheroma plaques was investigated in Apoe-deficient mice, a model of accelerated atherosclerosis.

METHODS

Two isocaloric Western purified diets containing 20% fat, either as S-VO or as dairy butter, were used to feed 28 males and 16 females of two-month-old Apoe-deficient mice for 12 weeks. S-VO was prepared by blending more than 75% virgin olive oil with other vegetal natural fat to obtain a solid fat. Plasma total cholesterol, triglycerides and HDL cholesterol were measured. Hepatic lipid droplets were analyzed. Areas of atherosclerotic aortic lesions were quantified in cross-sectional images of the proximal aorta and en face analysis of the whole aorta.

RESULTS

Total plasma cholesterol was increased in mice on the butter-supplemented diet in both female and male mice compared to S-VO, and the ratio of TC/HDL-cholesterol was significantly lower in S-VO than in the butter diet, although only in males, and no differences in plasma triglycerides were observed. No significant differences in hepatic lipid droplets were observed between diets in either sex. Aortic lesion areas were significantly higher in mice consuming the butter versus the S-VO diet in both sexes.

CONCLUSION

Extra virgin olive oil prepared in spreadable form maintained the delay in atheroma plaque progression compared to butter.

Empagliflozin alters lipid metabolism in the myocardium and liver in a prediabetes model with severe dyslipidemia

Background and aims

Recent studies suggest that empagliflozin reduces total and cardiovascular mortality in both diabetic and nondiabetic subjects. Although the exact mechanism is unclear, it is understood to positively affect myocardial energetics, including the metabolism of ketone bodies, lipids, and fatty acids. In this study, we compared empagliflozin effects on lipid metabolism in the heart and liver in a prediabetic rat model with severe dyslipidemia.

Materials and methods

Wistar rats served as the control group, while hereditary hypertriglyceridemic (HHTg) rats were used as a nonobese, prediabetic model. Rats were treated with or without empagliflozin at a dose of 10 mg/kg body weight (BW) for 8 weeks.

Results

In HHTg rats, empagliflozin decreased body weight and adiposity, improved glucose tolerance, and decreased serum triacylglycerols (TAGs) (p < 0.001). Empagliflozin decreased the activity and gene expression of the lipogenic enzyme SCD-1 (p < 0.001) in the myocardium, which may have led to a decrease in the ectopic accumulation of TAGs and lipotoxic diacylglycerols and lysophosphatidylcholines (p < 0.001). Changes in the myocardial phosphatidylcholine/phosphatidylethanolamine ratio (p < 0.01) and in the fatty acid profile of myocardial phospholipids may have contributed to the antifibrotic effects of empagliflozin. The anti-inflammatory effects of empagliflozin were evidenced by an increased IL-10/TNFα ratio (p < 0.001), a marked decrease in arachidonic acid metabolites (20-HETE, p < 0.001), and an increase in PUFA metabolites (14,15-EETs, p < 0.001) in the myocardium. However, empagliflozin did not significantly affect either the concentration or utilization of ketone bodies. In the liver, empagliflozin decreased lipogenesis and the accumulation of TAGs and lipotoxic intermediates. Its effect on arachidonic acid metabolites and alterations in n-3 PUFA metabolism was less pronounced than in the myocardium.

Conclusion

Our findings suggest that empagliflozin treatment in the heart and liver reduced the accumulation of neutral lipids and lipotoxic intermediates and altered the metabolism of n-3 PUFA. In the heart, empagliflozin altered arachidonic acid metabolism, which is likely associated with the anti-inflammatory and antifibrotic effects of the drug. We assume that these alterations in lipid metabolism contribute to the cardioprotective effects of empagliflozin in prediabetic states with severe dyslipidemia.

MUFA synthesis and stearoyl-CoA desaturase as a new pharmacological target for modulation of lipid and alpha-synuclein interaction against Parkinson's disease synucleinopathy

Protein pathology spreading within the nervous system, accompanies neurodegeneration and a spectrum of motor and cognitive dysfunctions. Currently available therapies against Parkinson's disease and other synucleinopathies are mostly symptomatic and fail to slow the disease progression in the long term. Modification of α-synuclein (αS) aggregation and toxicity of its pathogenic forms is one of the main goals in neuroprotective approach. Since the discovery of lipid component of Lewy bodies, fatty acids became a crucial, yet little explored target for research. MUFAs (monounsaturated fatty acids) are substrates for lipids, such as phospholipids, triglycerides and cholesteryl esters. They regulate membrane fluidity, take part in signal transduction, cellular differentiation and other fundamental processes. αS and MUFA interactions are essential for Lewy body pathology. αS increases levels of MUFAs, mainly oleic acid, which in turn can enhance αS toxicity and aggregation. Thus, reduction of MUFAs synthesis by inhibition of stearoyl-CoA desaturase (SCD) activity could be the new way to prevent aggravation of αS pathology. Due to the limited distribution in peripheral tissues, SCD5 is a potential target in novel therapies and therefore could be an important starting point in search for disease-modifying neuroprotective therapy. Here we summarize facts about physiology and pathology of αS, explain recently discovered lipid-αS interactions, review SCD function and involved mechanisms, present available SCD inhibitors and discuss their pharmacological potential in disease management. Modulation of MUFA synthesis, decreasing αS and lipid toxicity is clearly essential, but unexplored avenue in pharmacotherapy of Parkinson's disease and synucleinopathies.

SCD1-related epigenetic modifications affect hormone-sensitive lipase (Lipe) gene expression in cardiomyocytes

Stearoyl-CoA desaturase 1 (SCD1) is an enzyme that is involved in the regulation of lipolysis in the heart. SCD1 also affects epigenetic mechanisms, such as DNA and histone modifications, in various tissues. Both epigenetic modifications and changes in lipid metabolism are involved in the heart's response to hypoxia. The present study tested the hypothesis that SCD1 and epigenetic modifications interact to control lipolysis in cardiomyocytes under normoxic and hypoxic conditions. We found that the inhibition of SCD1 activity and loss of SCD1 expression reduced global DNA methylation levels, DNA methyltransferase (DNMT) activity, and DNMT1 expression in HL-1 cardiomyocytes and the mouse heart. We also found that the inhibition of adipose triglyceride lipase is involved in the control of global DNA methylation levels in cardiomyocytes in an SCD1-independent manner. Additionally, SCD1 inhibition reduced expression of the hormone-sensitive lipase (Lipe) gene through an increase in methylation of the Lipe gene promoter. Under hypoxic conditions, SCD1 inhibition abolished hypoxia-inducible transcription factor 1α, likely through decreases in histone deacetylase, protein kinase A, and abhydrolase domain containing 5 protein levels, leading to the attenuation of DNA hypomethylation by DNMT1. Hypoxia led to demethylation of the Lipe promoter in cardiomyocytes with SCD1 inhibition, which increased Lipe expression. These results indicate that SCD1 is involved in the control of epigenetic mechanisms in the heart and may affect Lipe expression through changes in methylation in its promoter region. Therefore, SCD1 may be considered a key player in the epigenetic response to normoxia and hypoxia in cardiomyocytes.

SCD1 is the critical signaling hub to mediate metabolic diseases: Mechanism and the development of its inhibitors

Metabolic diseases, featured with dysregulated energy homeostasis, have become major global health challenges. Patients with metabolic diseases have high probability to manifest multiple complications in lipid metabolism, e.g. obesity, insulin resistance and fatty liver. Therefore, targeting the hub genes in lipid metabolism may systemically ameliorate the metabolic diseases, along with the complications. Stearoyl-CoA desaturase 1(SCD1) is a key enzyme that desaturates the saturated fatty acids (SFAs) derived from de novo lipogenesis or diet to generate monounsaturated fatty acids (MUFAs). SCD1 maintains the metabolic and tissue homeostasis by responding to, and integrating the multiple layers of endogenous stimuli, which is mediated by the synthesized MUFAs. It critically regulates a myriad of physiological processes, including energy homeostasis, development, autophagy, tumorigenesis and inflammation. Aberrant transcriptional and epigenetic activation of SCD1 regulates AMPK/ACC, SIRT1/PGC1α, NcDase/Wnt, etc, and causes aberrant lipid accumulation, thereby promoting the progression of obesity, non-alcoholic fatty liver, diabetes and cancer. This review critically assesses the integrative mechanisms of the (patho)physiological functions of SCD1 in metabolic homeostasis, inflammation and autophagy. For translational perspective, potent SCD1 inhibitors have been developed to treat various types of cancer. We thus discuss the multidisciplinary advances that greatly accelerate the development of SCD1 new inhibitors. In conclusion, besides cancer treatment, SCD1 may serve as the promising target to combat multiple metabolic complications simultaneously.

Single-Cell RNA Sequencing Reveals That Adaptation of Human Aortic Endothelial Cells to Antiproliferative Therapies Is Modulated by Flow-Induced Shear Stress

BACKGROUND

Endothelial cells (ECs) are capable of quickly responding in a coordinated manner to a wide array of stresses to maintain vascular homeostasis. Loss of EC cellular adaptation may be a potential marker for cardiovascular disease and a predictor of poor response to endovascular pharmacological interventions such as drug-eluting stents. Here, we report single-cell transcriptional profiling of ECs exposed to multiple stimulus classes to evaluate EC adaptation.

METHODS

Human aortic ECs were costimulated with both pathophysiological flows mimicking shear stress levels found in the human aorta (laminar and turbulent, ranging from 2.5 to 30 dynes/cm2) and clinically relevant antiproliferative drugs, namely paclitaxel and rapamycin. EC state in response to these stimuli was defined using single-cell RNA sequencing.

RESULTS

We identified differentially expressed genes and inferred the TF (transcription factor) landscape modulated by flow shear stress using single-cell RNA sequencing. These flow-sensitive markers differentiated previously identified spatially distinct subpopulations of ECs in the murine aorta. Moreover, distinct transcriptional modules defined flow- and drug-responsive EC adaptation singly and in combination. Flow shear stress was the dominant driver of EC state, altering their response to pharmacological therapies.

CONCLUSIONS

We showed that flow shear stress modulates the cellular capacity of ECs to respond to paclitaxel and rapamycin administration, suggesting that while responding to different flow patterns, ECs experience an impairment in their transcriptional adaptation to other stimuli.

Development of a novel Guinea Pig model producing transgenerational endothelial transcriptional changes driven by maternal food restriction and a second metabolic insult of high fat diet

Developmental programming of chronic adverse cardiovascular health outcomes has been studied both using numerous human populations and an array of animal models. However, the mechanisms that produce transgenerational effects have been difficult to study due to a lack of developmentally relevant models. As such, how increased disease risk is carried to the second generation has been poorly studied. We hypothesized that the endothelium which mediates many acute and chronic vascular inflammatory responses is a key player in these effects, and epidemiological studies implicate transgenerational nutritional effects on endothelial health. To study the mutigenerational effects of maternal undernutrition on offspring endothelial health, we developed a model of transgenerational nutritional stress in guinea pigs, a translationally relevant precocial species with a relatively short lifespan. First- and second-generation offspring were subjected to a high fat diet in adolescence to exacerbate negative cardiovascular health. To assess transcriptional changes, we performed bulk RNA-sequencing in carotid artery endothelial cells, with groups stratified as prenatal control or food restricted, and postnatal control or high fat diet. We detected statistically significant gene alterations for each dietary permutation, some of which were unique to treatments and other transcriptional signatures shared by multiple or all conditions. These findings highlight a core group of genes altered by high fat diet that is shared by all cohorts and a divergence of transgenerational effects between the prenatal ad libitum and dietary restriction groups. This study establishes the groundwork for this model to be used to better understand the interplay of prenatal stress and genetic reprogramming.