Delta-6-desaturase (FADS2) inhibition and omega-3 fatty acids in skeletal muscle protein turnover

A Comprehensive Insight and Mechanistic Understanding of the Lipidomic Alterations Associated With DCM

Dilated cardiomyopathy (DCM) is one of the major causes of heart failure characterized by the enlargement of the left ventricular cavity and contractile dysfunction of the myocardium. Lipids are the major sources of energy for the myocardium. Impairment of lipid homeostasis has a potential role in the pathogenesis of DCM. In this review, we have summarized the role of different lipids in the progression of DCM that can be considered as potential biomarkers. Further, we have also explained the mechanistic pathways followed by the lipid molecules in disease progression along with the cardioprotective role of certain lipids. As the global epidemiological status of DCM is alarming, it is high time to define some disease-specific biomarkers with greater prognostic value. We are proposing an adaptation of a system lipidomics-based approach to profile DCM patients in order to achieve a better diagnosis and prognosis of the disease.

ER stress and lipid imbalance drive embryonic cardiomyopathy in a human heart organoid model of pregestational diabetes

Congenital heart defects constitute the most common birth defect in humans, affecting approximately 1% of all live births. The incidence of congenital heart defects is exacerbated by maternal conditions, such as diabetes during the first trimester. Our ability to mechanistically understand these disorders is severely limited by the lack of human models and the inaccessibility to human tissue at relevant stages. Here, we used an advanced human heart organoid model that recapitulates complex aspects of heart development during the first trimester to model the effects of pregestational diabetes in the human embryonic heart. We observed that heart organoids in diabetic conditions develop pathophysiological hallmarks like those previously reported in mouse and human studies, including ROS-mediated stress and cardiomyocyte hypertrophy, among others. Single cell RNA-seq revealed cardiac cell type specific-dysfunction affecting epicardial and cardiomyocyte populations, and suggested alterations in endoplasmic reticulum function and very long chain fatty acid lipid metabolism. Confocal imaging and LC-MS lipidomics confirmed our observations and showed that dyslipidemia was mediated by fatty acid desaturase 2 (FADS2) mRNA decay dependent on IRE1-RIDD signaling. We also found that the effects of pregestational diabetes could be reversed to a significant extent using drug interventions targeting either IRE1 or restoring healthy lipid levels within organoids, opening the door to new preventative and therapeutic strategies in humans.

The integrative panel of fatty acid desaturase-2 (FADS2) rs174583 gene polymorphism and dietary indices (DQI-I and HEI) affects cardiovascular risk factors among obese individuals

BACKGROUND

Recent studies have shown that dietary intakes and gene variants have a critical role in the obesity related comorbidities. This study aimed to evaluate the effects of the interactions between Fatty acid desaturase 2 (FADS2) gene rs174583 polymorphism and two dietary indices on cardiometabolic risk factors.

METHODS

This cross-sectional study was carried out on 347 obese adults aged 20-50 years old in Tabriz, Iran. Healthy eating index (HEI) and Diet quality index-international (DQI-I) were evaluated by a validated semi-quantitative 147-item Food frequency questionnaire (FFQ). Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to determine FADS2 gene variants. Multivariate analysis of covariance (MANCOVA) was used to identify gene-diet interactions on metabolic parameters.

RESULTS

Waist circumference (WC) and serum triglyceride (TG) levels were significantly higher among carriers of TT genotype of FADS2 gene (P < 0.05). In addition, the interactions between FADS2 gene rs174583 polymorphism and DQI-I had significant effects on weight (P _interaction = 0.01), fat mass (P _interaction = 0.04), fat free mass (P _interaction = 0.03), and Body mass index (BMI) (P _interaction = 0.02); the highest level of these parameters belonged to TT carriers. Similarly, the interactions between FADS2 gene variants and HEI had significant effects on insulin (P _interaction < 0.001), Homeostasis model assessment of insulin resistance (HOMA-IR) (P _interaction < 0.001), Quantitative insulin check index (QUICKI) (P _interaction = 0.001), and alpha Melanocyte stimulating hormone (α-MSH) (P _interaction = 0.03).

CONCLUSION

In this study, for the first time, we reported the effects of gene-diet interactions on metabolic traits. Compliance with dietary indices (DQI-I and HEI) ameliorated the adverse effects of gene variants on metabolic risk factors, especially in heterogeneous genotypes. Further prospective cohort studies are needed to confirm these results.

Maternal PUFAs, Placental Epigenetics, and Their Relevance to Fetal Growth and Brain Development

Dietary polyunsaturated fatty acids (PUFAs), especially omega-3 (n-3) and n-6 long-chain (LC) PUFAs, are indispensable for the fetus' brain supplied by the placenta. Despite being highly unsaturated, n-3 LCPUFA-docosahexaenoic acid (DHA) plays a protective role as an antioxidant in the brain. Deficiency of DHA during fetal development may cause irreversible damages in neurodevelopment programming. Dietary PUFAs can impact placental structure and functions by regulating early placentation processes, such as angiogenesis. They promote remodeling of uteroplacental architecture to facilitate increased blood flow and surface area for nutrient exchange. The placenta's fatty acid transfer depends on the uteroplacental vascular development, ensuring adequate maternal circulatory fatty acids transport to fulfill the fetus' rapid growth and development requirements. Maternal n-3 PUFA deficiency predominantly leads to placental epigenetic changes than other fetal developing organs. A global shift in DNA methylation possibly transmits epigenetic instability in developing fetuses due to n-3 PUFA deficiency. Thus, an optimal level of maternal omega-3 (n-3) PUFAs may protect the placenta's structural and functional integrity and allow fetal growth by controlling the aberrant placental epigenetic changes. This narrative review summarizes the recent advances and underpins the roles of maternal PUFAs on the structure and functions of the placenta and their relevance to fetal growth and brain development.

Goat FADS2 controlling fatty acid metabolism is directly regulated by SREBP1 in mammary epithelial cells

Goat milk provides benefits to human health due to its richness in bioactive components, such as polyunsaturated fatty acids (PUFAs). The fatty acid desaturase 2 (FADS2) is the first rate-limiting enzyme in PUFAs biosynthesis. However, its role and transcriptional regulation mechanisms in fatty acid metabolism in dairy goat remain unclear. Here, our study revealed that the FADS2 gene was highly expressed during the peak lactation compared with the dry period, early lactation, and late lactation. The content of triacylglycerol (TAG) was enhanced with the increasing mRNA expression of TAG synthesis genes (diacylglycerol acyltransferase 1/2, DGAT1/2) in FADS2-overexpressed goat mammary epithelial cells (GMECs). Overexpression of FADS2 was positively correlated with the elevated concentrations of dihomo-gamma-linolenic acid (DGLA) and docosahexaenoic acid (DHA) in GMECs. BODIPY staining showed that FADS2 promoted lipid droplet accumulation in GMECs. To clarify the transcriptional regulatory mechanisms of FADS2, 2,226 bp length of FADS2 promoter was obtained. Deletion mutation assays revealed that the core region of FADS2 promoter was located between the -375 and -26 region, which contained SRE1 (-361/-351) and SRE2 (-191/-181) cis-acting elements of transcription factor sterol regulatory element-binding protein 1 (SREBP1). Overexpression of SREBP1 enhanced relative luciferase activity of the single mutant of SRE1 or SRE2, vice versa, and failed to alter the relative luciferase activity of the joint mutant of SRE1 and SRE2. Chromatin immunoprecipitation (ChIP) and site-directed mutation assays further demonstrated that SREBP1 regulated the transcription of the FADS2 gene by binding to SRE sites in vivo and in vitro. In addition, the mRNA levels of FADS2 were significantly decreased by targeting SRE1 and SRE2 sites in the genome via the CRISPR interference (CRISPRi) system. These findings establish a direct role for FADS2 regulating TAG and fatty acid synthesis by SREBP1 transcriptional regulation in dairy goat, providing new insights into fatty acid metabolism in mammary gland of ruminants.

The relationship between n-3 polyunsaturated fatty acids and telomere: A review on proposed nutritional treatment against metabolic syndrome and potential signaling pathways

Metabolic syndrome (MetS), a cluster of metabolic abnormalities composed of central obesity, elevated blood pressure, glucose disturbances, hypercholesterolemia and dyslipidaemia, has increasingly become a public health problem in the 21st century worldwide. The dysfunction of telomeres, the repetitive DNA with highly conserved sequences (5'-TTAGGG-3'), is remarkably correlated with organismal aging, even suggesting a causal relationship with metabolic disorders. The health benefits of n-3 polyunsaturated fatty acids (PUFAs) in multiple disorders are associated with telomere length in evidence, which have recently drawn wide attention. However, functional targets and pathways for the associations of n-3 PUFAs and telomere with MetS remain scare. Few studies have summarized the role of n-3 PUFAs in DNA damage repair pathways, anti-inflammatory pathways, and redox balance, linking with telomere biology, and other potential telomere-related signaling pathways. This review aims to (i) elucidate how n-3 PUFAs ameliorate telomere attrition in the context of anti-oxidation and anti-inflammation; (ii) unravel the role of n-3 PUFAs in modulating telomere-related neuron dysfunction and regulating the neuro-endocrine-immunological network in MetS; (iii) epidemiologically implicate the associations of metabolic disorders and n-3 PUFAs with telomere length; and (iv) suggest promising biochemical approaches and advancing methodologies to overcome the inter-variation problem helpful for future research.

Hemp seed significantly modulates the endocannabinoidome and produces beneficial metabolic effects with improved intestinal barrier function and decreased inflammation in mice under a high-fat, high-sucrose diet as compared with linseed

Omega-3 fatty acids support cardiometabolic health and reduce chronic low-grade inflammation. These fatty acids may impart their health benefits partly by modulating the endocannabinoidome and the gut microbiome, both of which are key regulators of metabolism and the inflammatory response. Whole hemp seeds (Cannabis sativa) are of exceptional nutritional value, being rich in omega-3 fatty acids. We assessed the effects of dietary substitution (equivalent to about 2 tablespoons of seeds a day for humans) of whole hemp seeds in comparison with whole linseeds in a diet-induced obesity mouse model and determined their effects on obesity and the gut microbiome-endocannabinoidome axis. We show that whole hemp seed substitution did not affect weigh gain, adiposity, or food intake, whereas linseed substitution did, in association with higher fasting glucose levels, greater insulin release during an oral glucose tolerance test, and higher levels of liver triglycerides than controls. Furthermore, hemp seed substitution mitigated diet-induced obesity-associated increases in intestinal permeability and circulating PAI-1 levels, while having no effects on markers of inflammation in epididymal adipose tissue, which were, however, increased in mice fed linseeds. Both hemp seeds and linseeds were able to modify the expression of several endocannabinoidome genes and markedly increased the levels of several omega-3 fatty acid–derived endocannabinoidome bioactive lipids with previously suggested anti-inflammatory actions in a tissue specific manner, despite the relatively low level of seed substitution. While neither diet markedly modified the gut microbiome, mice on the hemp seed diet had higher abundance of Clostridiaceae 1 and Rikenellaceae than mice fed linseed or control diet, respectively. Thus, hemp seed-containing foods might represent a source of healthy fats that are not likely to exacerbate the metabolic consequences of obesogenic diets while producing intestinal permeability protective effects and some anti-inflammatory actions.

N-3 Fatty Acid Supplementation Impacts Protein Metabolism Faster Than it Lowers Proinflammatory Cytokines in Advanced Breast Cancer Patients: Natural 15N/14N Variations during a Clinical Trial

While clinical evidence remains limited, an extensive amount of research suggests a beneficial role of n-3 polyunsaturated fatty acid supplementation in cancer treatment. One potential benefit is an improvement of protein homeostasis, but how protein metabolism depends on proinflammatory cytokines in this context remains unclear. Here, using the natural abundance of the stable isotopes of nitrogen as a marker of changes in protein metabolism during a randomized, double-blind, controlled clinical trial, we show that protein homeostasis is affected way faster than proinflammatory cytokines in metastatic breast cancer patients supplemented with n-3 polyunsaturated fatty acids. We provide some evidence that this response is unrelated to major changes in whole-body substrate oxidation. In addition, we demonstrate that more fatty acids were impacted by metabolic regulations than by differences in their intake levels during the supplementation. This study documents that the percentage of patients that complied with the supplementation decreased with time, making compliance assessment crucial for the kinetic analysis of the metabolic and inflammatory responses. Our results highlight the time-dependent nature of metabolic and inflammatory changes during long-chain n-3 fatty acid supplementation.

A Novel Strategy for the Production of Edible Insects: Effect of Dietary Perilla Seed Supplementation on Nutritional Composition, Growth Performance, Lipid Metabolism, and Δ6 Desaturase Gene Expression of Sago Palm Weevil (Rhynchophorus ferrugineus) Larvae

The nutritional value, growth performance, and lipid metabolism of sago palm weevil larvae (Rhynchophorus ferrugineus, SPWL) raised on plant-based diets (soybean, rice bran, and ground sago palm trunk (GSPT)), supplemented with various concentrations (0, 3, 7, 15, and 20%) of perilla seed (PS) were compared with traditional diets i.e., regular GSPT (control) and GSPT supplemented with pig feed. All supplemented diets rendered SPWL with higher lipid and protein contents (p < 0.05). Supplementing with 7−20% PS enhanced α-linoleic acid content in SPWL, resulting in a decrease in the n-6:n-3 ratio to a desirable level. Dietary PS supplementation increased Δ9 (18), total Δ9 and Δ5 + Δ6 desaturase indexes, fatty acid (FA) unsaturation, and the polyunsaturated FA:saturated FA ratio in SPWL, while lowering atherogenicity index, thrombogenicity index, and Δ6 desaturase (fads2) gene expression. Boosting with 7% PS improved the majority of growth parameters and enhanced essential amino acid and mineral contents (p < 0.05).

Personalized diet study of dietary advanced glycation end products (AGEs) and fatty acid desaturase 2 (FADS2) genotypes in obesity

Obesity prevalence have tripled in the past decades. It is logical to consider new approaches to halt its prevalence. In this concept, considering the effect of interaction between fatty acid desaturase 2 (FADS₂) gene variants and dietary advanced glycation end products (AGEs) on obesity-related characteristics seems to be challenging. The present cross-sectional study conducted among 347 obese individuals. A validated semi-quantitative 147-item food frequency questionnaire (FFQ) was used to estimate dietary intakes and American multiethnic database was used to calculate AGEs content of food items which were not available in Iranian Food Composition Table (FCT). FADS₂ gene variants were determined according to Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Analysis of covariance (ANCOVA) was used to evaluate the modifier effect of FADS₂ gene-dietary AGEs on biochemical values. Based on our findings, no significant differences was reported in term of biochemical variables between AGEs tertiles. In contrast, percent of macronutrients (carbohydrate, protein and fat) of total calorie intake, amount of daily intake of fiber and meat groups showed a significant differences among AGEs tertiles. Furthermore, statistical assays clarified the modifier effects of FADS₂ gene-AGEs on weight (P_interaction = 0.04), fat mass (P_interaction = 0.03), waist circumference (P_interaction = 0.008) and cholesterol (P_interaction = 0.04) level. Accordingly, higher consumption of protein or fat based foods constitute high amount of AGEs and heterozygote genotype for FADS₂ tended to show lower level of AGEs content. These findings address further investigation to develop new approaches for nutritional interventions.

Maternal n-3 PUFA deficiency alters uterine artery remodeling and placental epigenome in the mice

The maternal n-3 polyunsaturated fatty acid (PUFA) deficiency on decidual vascular structure and angiogenesis in mice placenta was investigated. Namely, we studied uterine artery remodeling, fatty acid metabolism, and placental epigenetic methylation in this animal model. Weanling female Swiss albino mice were fed either alpha-linolenic acid (18:3 n-3, ALA) deficient diets (0.13% energy from ALA) or a sufficient diet (2.26% energy from ALA) throughout the study. The dietary n-3 PUFA deficiency altered uteroplacental morphology and vasculature by reversing luminal to vessel area and increased luminal wall thickness at 8.5-12.5gD. Further, placentas (F0 and F1) showed a significant decrease in the expression of VCAM1, HLAG proteins and an increase in MMP9, KDR expression. The conversion of ALA to long-chain (LC) n-3 PUFAs was significantly decreased in plasma and placenta during the n-3 deficiency state. Reduced n-3 LCPUFAs increased the placental expression of intracellular proteins FABP3, FABP4, and ADRP to compensate decreased availability of these fatty acids in the n-3 deficient mice. The N-3 PUFA deficiency significantly increased the 5-methylcytosine levels in the placenta but not in the liver. The alteration in DNA methylation continued to the next generation in the placental epigenome with augmented expression of DNMT3A and DNMT3B. Our study showed that maternal n-3 PUFA deficiency alters placental vascular architecture and induces epigenetic changes suggesting the importance of n-3 PUFA intake during the development of the fetus. Moreover, the study shows that the placenta is the susceptible target for epigenetic alteration in maternal deficiency n-3 fatty acids.