Low levels and partial exposure to palmitic acid improves mitochondrial function and the oxidative status of cultured cardiomyoblasts

Prolonged exposure to simvastatin affects coenzyme Q9/10 status leading to impaired mitochondrial respiratory capacity and reduced viability of cultured cardiac cells

This study investigates the effects of prolonged simvastatin exposure on coenzyme Q9/10 (CoQ9/10) levels, an essential component of antioxidant defense, in cultured cardiac cells. Statins, commonly used to manage dyslipidemia and reduce cardiovascular risk, may impair mitochondrial function, but their impact on CoQ10 depletion and oxidative stress is not well understood. We examined the influence of simvastatin on mitochondrial oxidative capacity, reactive oxygen species (ROS) production, and CoQ9/10 status at concentrations of 0.3, 0.6, 1.25, 2.5, 5, 10, and 20 μM, over durations of 24, 48, and 72 h. Using an in vitro model of cultured H9c2 cardiomyoblasts, our results showed that short-term exposure (24 h) at lower concentrations (<5 μM) enhanced cytosolic and mitochondrial ROS levels without affecting mitochondrial function or CoQ9/10 status. However, prolonged exposure to higher concentrations (≥10 μM for >48 h) resulted in impaired mitochondrial oxidative capacity, indicated by increased proton leak and elevated ROS levels, which were followed by significantly reduced cell viability. These findings suggest that prolonged, high-dose simvastatin exposure may disrupt the oxidative balance of CoQ9/10, leading to myocardial injury. This research addresses a gap in understanding the long-term effects of statins on mitochondrial health and underscores the need for further studies to optimize statin therapy and minimize adverse effects on myocardial function.

Lipid exposure leads to metabolic dysfunction in fetal sheep cardiomyocytes

Fetal circulating lipids are low but rise precipitously following birth. It is unknown how prematurely elevated lipids affect the fetal heart, which primarily uses carbohydrates for energy. Fetal sheep were surgically instrumented and received Intralipid 20® or Lactated Ringer's Solution intravenously. After 8 days, myocardial biopsies were taken, and cardiomyocytes were dispersed. Lipid uptake was assessed by labeled saturated long-chain fatty acids (LCFA) and very long-chain fatty acids (VLCFA) incorporation. Maximal oxygen consumption rates (OCR) were measured. Gene and protein expression levels were measured by quantitative PCR and Western blotting. Intralipid treatment increased LCFA (p < 0.001) and VLCFA (p < 0.001) lipid droplet number, and LCFA (males p = 0.002) and VLCFA (p = 0.018) droplet size. Fetal Intralipid treatment reduced maximal OCR in basal media (p = 0.005). Palmitic acid decreased maximal OCR regardless of fetal treatment or length of in vitro exposure (p = 0.006). Fetal Intralipid upregulated genes included CD36 (p = 0.001), CPT1A (p < 0.001), CPT1B (p < 0.001), VLCAD (p < 0.001), and PDK4 (p < 0.001), with no differences in protein expression. There were no effects on ER stress, apoptosis, or autophagy markers. Extended elevated lipid levels in the fetus increased lipid uptake and may have shifted substrate preference towards lipids, but all lipid exposure depressed fetal cardiac metabolism. Prematurely elevated lipids mature but suppress oxidative metabolism.

Supplementation with aspalathin and sulforaphane protects cultured cardiac cells against dyslipidemia-associated oxidative damage

Dyslipidemia is a prominent pathological feature responsible for oxidative stress-induced cardiac damage. Due to their high antioxidant content, dietary compounds, such as aspalathin and sulforaphane, are increasingly explored for their cardioprotective effects against lipid-induced toxicity. Cultured H9c2 cardiomyoblasts, an in vitro model routinely used to assess the pharmacological effect of drugs, were pretreated with the dietary compounds, aspalathin (1 μM) and sulforaphane (10 μM) before exposure to palmitic acid (0.25 mM) to induce lipidemic-related complications. The results showed that both aspalathin and sulforaphane enhanced cellular metabolic activity and improved mitochondrial respiration correlating with improved mRNA expression of genes involved in mitochondrial function, including uncoupling protein 2, peroxisome proliferator-activated receptor, gamma coactivator 1-alpha, nuclear respiratory factor 1, and ubiquinol-cytochrome c reductase complex assembly factor 1. Beyond attenuating lipid peroxidation, the dietary compounds also suppressed intracellular reactive oxygen species and enhanced antioxidant responses, including the mRNA expression of nuclear factor erythroid 2-related factor 2. These envisaged benefits were associated with decreased cellular apoptosis. This preclinical study supports and warrants further investigation into the potential benefits of these dietary compounds or foods rich in aspalathin or sulforaphane in protecting against lipid-induced oxidative damage within the myocardium.

Protection Strategies Against Palmitic Acid-Induced Lipotoxicity in Metabolic Syndrome and Related Diseases

Diets rich in carbohydrate and saturated fat contents, when combined with a sedentary lifestyle, contribute to the development of obesity and metabolic syndrome (MetS), which subsequently increase palmitic acid (PA) levels. At high concentrations, PA induces lipotoxicity through several mechanisms involving endoplasmic reticulum (ER) stress, mitochondrial dysfunction, inflammation and cell death. Nevertheless, there are endogenous strategies to mitigate PA-induced lipotoxicity through its unsaturation and elongation and its channeling and storage in lipid droplets (LDs), which plays a crucial role in sequestering oxidized lipids, thereby reducing oxidative damage to lipid membranes. While extended exposure to PA promotes mitochondrial reactive oxygen species (ROS) generation leading to cell damage, acute exposure of ß-cells to PA increases glucose-stimulated insulin secretion (GSIS), through the activation of free fatty acid receptors (FFARs). Subsequently, the activation of FFARs by exogenous agonists has been suggested as a potential therapeutic strategy to prevent PA-induced lipotoxicity in ß cells. Moreover, some saturated fatty acids, including oleic acid, can counteract the negative impact of PA on cellular health, suggesting a complex interaction between different dietary fats and cellular outcomes. Therefore, the challenge is to prevent the lipid peroxidation of dietary unsaturated fatty acids through the utilization of natural antioxidants. This complexity indicates the necessity for further research into the function of palmitic acid in diverse pathological conditions and to find the main therapeutic target against its lipotoxicity. The aim of this review is, therefore, to examine recent data regarding the mechanism underlying PA-induced lipotoxicity in order to identify strategies that can promote protection mechanisms against lipotoxicity, dysfunction and apoptosis in MetS and obesity.

Cardiolipin remodeling maintains the inner mitochondrial membrane in cells with saturated lipidomes

Cardiolipin (CL) is a unique, four-chain phospholipid synthesized in the inner mitochondrial membrane (IMM). The acyl chain composition of CL is regulated through a remodeling pathway, whose loss causes mitochondrial dysfunction in Barth syndrome (BTHS). Yeast has been used extensively as a model system to characterize CL metabolism, but mutants lacking its two remodeling enzymes, Cld1p and Taz1p, exhibit mild structural and respiratory phenotypes compared to mammalian cells. Here, we show an essential role for CL remodeling in the structure and function of the IMM in yeast grown under reduced oxygenation. Microaerobic fermentation, which mimics natural yeast environments, caused the accumulation of saturated fatty acids and, under these conditions, remodeling mutants showed a loss of IMM ultrastructure. We extended this observation to HEK293 cells, where phospholipase A2 inhibition by Bromoenol lactone resulted in respiratory dysfunction and cristae loss upon mild treatment with exogenous saturated fatty acids. In microaerobic yeast, remodeling mutants accumulated unremodeled, saturated CL, but also displayed reduced total CL levels, highlighting the interplay between saturation and CL biosynthesis and/or breakdown. We identified the mitochondrial phospholipase A1 Ddl1p as a regulator of CL levels, and those of its precursors phosphatidylglycerol and phosphatidic acid, under these conditions. Loss of Ddl1p partially rescued IMM structure in cells unable to initiate CL remodeling and had differing lipidomic effects depending on oxygenation. These results introduce a revised yeast model for investigating CL remodeling and suggest that its structural functions are dependent on the overall lipid environment in the mitochondrion.

Caspase-4/11 promotes hyperlipidemia and chronic kidney disease-accelerated vascular inflammation by enhancing trained immunity

To determine whether hyperlipidemia and chronic kidney disease (CKD) have a synergy in accelerating vascular inflammation via trained immunity (TI), we performed aortic pathological analysis and RNA-Seq of high-fat diet-fed (HFD-fed) 5/6 nephrectomy CKD (HFD+CKD) mice. We made the following findings: (a) HFD+CKD increased aortic cytosolic LPS levels, caspase-11 (CASP11) activation, and 998 gene expressions of TI pathways in the aorta (first-tier TI mechanism); (b) CASP11-/- decreased aortic neointima hyperplasia, aortic recruitment of macrophages, and casp11-gasdermin D-mediated cytokine secretion; (c) CASP11-/- decreased N-terminal gasdermin D (N-GSDMD) membrane expression on aortic endothelial cells and aortic IL-1B levels; (d) LPS transfection into human aortic endothelial cells resulted in CASP4 (human)/CASP11 (mouse) activation and increased N-GSDMD membrane expression; and (e) IL-1B served as the second-tier mechanism underlying HFD+CKD-promoted TI. Taken together, hyperlipidemia and CKD accelerated vascular inflammation by promoting 2-tier trained immunity.

Spermacoce alata Aubl. Essential Oil: Chemical Composition, In Vitro Antioxidant Activity, and Inhibitory Effects of Acetylcholinesterase, α-Glucosidase and β-Lactamase

Spermacoce alata Aubl. is widely available in the market as traditional Chinese medicine and animal feed, due to its properties of clearing heat and treating malaria and its high-protein and crude fiber content. In this study, the essential oil of S. alata was obtained through hydrodistillation. GC-MS and GC-FID methods were used to identify the chemical components and their relative abundance. Furthermore, the antioxidant capacity was measured using DPPH, ABTS, and FRAP assays, and the inhibitory effects of acetylcholinesterase, α-glucosidase, and β-lactamase were also evaluated. A total of 67 compounds were identified, with the major constituents being palmitic acid (30.74%), linoleic acid (16.13%), and phenylheptatriyne (8.07%). The essential oil exhibited moderate antioxidant activity against DPPH (IC50 > 10 mg/mL), while the IC50 value for the ABTS assay was 3.84 ± 2.12 mg/mL and the FRAP assay value was 87.22 ± 12.22 µM/g. Additionally, the essential oil showed moderate anti-acetylcholinesterase activity (IC50 = 286.0 ± 79.04 μg/mL), significant anti-α-glucosidase activity (IC50 = 174.7 ± 13.12 μg/mL), and potent anti-β-lactamase activity (IC50 = 37.56 ± 3.48 μg/mL). The results suggest that S. alata has the potential for application in pharmacology, warranting further exploration and investigation.

Raman Imaging-A Valuable Tool for Tracking Fatty Acid Metabolism-Normal and Cancer Human Colon Single-Cell Study

Altered metabolism of lipids is a key factor in many diseases including cancer. Therefore, investigations into the impact of unsaturated and saturated fatty acids (FAs) on human body homeostasis are crucial for understanding the development of lifestyle diseases. In this paper, we focus on the impact of palmitic (PA), linoleic (LA), and eicosapentaenoic (EPA) acids on human colon normal (CCD-18 Co) and cancer (Caco-2) single cells using Raman imaging and spectroscopy. The label-free nature of Raman imaging allowed us to evaluate FAs dynamics without modifying endogenous cellular metabolism. Thanks to the ability of Raman imaging to visualize single-cell substructures, we have analyzed the changes in chemical composition of endoplasmic reticulum (ER), mitochondria, lipid droplets (LDs), and nucleus upon FA supplementation. Analysis of Raman band intensity ratios typical for lipids, proteins, and nucleic acids (I1656/I1444, I1444/I1256, I1444/I750, I1304/I1256) proved that, using Raman mapping, we can observe the metabolic pathways of FAs in ER, which is responsible for the uptake of exogenous FAs, de novo synthesis, elongation, and desaturation of FAs, in mitochondria responsible for energy production via FA oxidation, in LDs specialized in cellular fat storage, and in the nucleus, where FAs are transported via fatty-acid-binding proteins, biomarkers of human colon cancerogenesis. Analysis for membranes showed that the uptake of FAs effectively changed the chemical composition of this organelle, and the strongest effect was noticed for LA. The spectroscopy studies have been completed using XTT tests, which showed that the addition of LA or EPA for Caco-2 cells decreases their viability with a stronger effect observed for LA and the opposite effect observed for PA. For normal cells, CCD-18 Co supplementation using LA or EPA stimulated cells for growing, while PA had the opposite impact.