An immunomodulating fatty acid analogue targeting mitochondria exerts anti-atherosclerotic effect beyond plasma cholesterol-lowering activity in apoe(-/-) mice

Changes in Plasma Pyruvate and TCA Cycle Metabolites upon Increased Hepatic Fatty Acid Oxidation and Ketogenesis in Male Wistar Rats

Altered hepatic mitochondrial fatty acid β-oxidation and associated tricarboxylic acid (TCA) cycle activity contributes to lifestyle-related diseases, and circulating biomarkers reflecting these changes could have disease prognostic value. This study aimed to determine hepatic and systemic changes in TCA-cycle-related metabolites upon the selective pharmacologic enhancement of mitochondrial fatty acid β-oxidation in the liver, and to elucidate the mechanisms and potential markers of hepatic mitochondrial activity. Male Wistar rats were treated with 3-thia fatty acids (e.g., tetradecylthioacetic acid (TTA)), which target mitochondrial biogenesis, mitochondrial fatty acid β-oxidation, and ketogenesis predominantly in the liver. Hepatic and plasma concentrations of TCA cycle intermediates and anaplerotic substrates (LC-MS/MS), plasma ketones (colorimetric assay), and acylcarnitines (HPLC-MS/MS), along with associated TCA-cycle-related gene expression (qPCR) and enzyme activities, were determined. TTA-induced hepatic fatty acid β-oxidation resulted in an increased ratio of plasma ketone bodies/nonesterified fatty acid (NEFA), lower plasma malonyl-CoA levels, and a higher ratio of plasma acetylcarnitine/palmitoylcarnitine (C2/C16). These changes were associated with decreased hepatic and increased plasma pyruvate concentrations, and increased plasma concentrations of succinate, malate, and 2-hydroxyglutarate. Expression of several genes encoding TCA cycle enzymes and the malate-oxoglutarate carrier (Slc25a11), glutamate dehydrogenase (Gdh), and malic enzyme (Mdh1 and Mdh2) were significantly increased. In conclusion, the induction of hepatic mitochondrial fatty acid β-oxidation by 3-thia fatty acids lowered hepatic pyruvate while increasing plasma pyruvate, as well as succinate, malate, and 2-hydroxyglutarate.

Marine n-3 polyunsaturated fatty acids: Efficacy on inflammatory-based disorders

Inflammation is a physiological response to injury, stimulating tissue repair and regeneration. However, the presence of peculiar individual conditions can negatively perturb the resolution phase eventually leading to a state of low-grade systemic chronic inflammation, characterized by tissue and organ damages and increased susceptibility to non-communicable disease. Marine n-3 polyunsaturated fatty acids (n-3 PUFAs), mainly eicosapentaenoic (EPA) and docosahexaenoic acid (DHA), are able to influence many aspects of this process. Experiments performed in various animal models of obesity, Alzheimer's disease and multiple sclerosis have demonstrated that n-3 PUFAs can modulate the basic mechanisms as well as the disease progression. This review describes the available data from experimental studies to the clinical trials.

liputils: a Python module to manage individual fatty acid moieties from complex lipids

Lipidomic analyses address the problem of characterizing the lipid components of given cells, tissues and organisms by means of chromatographic separations coupled to high-resolution, tandem mass spectrometry analyses. A number of software tools have been developed to help in the daunting task of mass spectrometry signal processing and cleaning, peak analysis and compound identification, and a typical finished lipidomic dataset contains hundreds to thousands of individual molecular lipid species. To provide researchers without a specific technical expertise in mass spectrometry the possibility of broadening the exploration of lipidomic datasets, we have developed liputils, a Python module that specializes in the extraction of fatty acid moieties from individual molecular lipids. There is no prerequisite data format, as liputils extracts residues from RefMet-compliant textual identifiers and from annotations of other commercially available services. We provide three examples of real-world data processing with liputils, as well as a detailed protocol on how to readily process an existing dataset that can be followed with basic informatics skills.

Fat-Shaped Microbiota Affects Lipid Metabolism, Liver Steatosis, and Intestinal Homeostasis in Mice Fed a Low-Protein Diet

SCOPE

Protein malnutrition is characterized by stunted growth, hepatic steatosis and a damaged gut mucosal architecture. Since high-fat shaped gut microbiota (HFM) has an increased ability in providing nutrients and energy from food to the host, the aim of this study is to determine whether such a microbiota could beneficially impact on the consequences of malnutrition.

METHODS AND RESULTS

The cecal content of specific pathogen free C57Bl/6J mice fed a high-fat diet or a low-protein diet is transplanted in two groups of germ-free C57Bl/6J recipient mice, which are subsequently fed a low-protein diet for 8 weeks. Body weight gain is comparable between the two groups of microbiota-recipient mice. The HFM led to a worsening of microvesicular steatosis and a decrease of plasma lipids compared to the low-protein shaped microbiota. In the small intestine of mice receiving the HFM, although significant histological differences are not observed, the expression of antimicrobial genes promoting oxidative stress and immune response at the ileal epithelium (Duox2, Duoxa2, Saa1, Ang4, Defa5) is increased.

CONCLUSION

The transplant of HFM in mice fed a low-protein diet represents a noxious stimulus for the ileal mucosa and impairs hepatic lipoprotein secretion, favoring the occurrence of hepatic microvesicular steatosis.

The PPAR pan-agonist tetradecylthioacetic acid promotes redistribution of plasma cholesterol towards large HDL

Tetradecylthioacetic acid (TTA) is a synthetic fatty acid with a sulfur substitution in the β-position. This modification renders TTA unable to undergo complete β-oxidation and increases its biological activity, including activation of peroxisome proliferator activated receptors (PPARs) with preference for PPARα. This study investigated the effects of TTA on lipid and lipoprotein metabolism in the intestine and liver of mice fed a high fat diet (HFD). Mice receiving HFD supplemented with 0.75% (w/w) TTA had significantly lower body weights compared to mice fed the diet without TTA. Plasma triacylglycerol (TAG) was reduced 3-fold with TTA treatment, concurrent with increase in liver TAG. Total cholesterol was unchanged in plasma and liver. However, TTA promoted a shift in the plasma lipoprotein fractions with an increase in larger HDL particles. Histological analysis of the small intestine revealed a reduced size of lipid droplets in enterocytes of TTA treated mice, accompanied by increased mRNA expression of fatty acid transporter genes. Expression of the cholesterol efflux pump Abca1 was induced in the small intestine, but not in the liver. Scd1 displayed markedly increased mRNA and protein expression in the intestine of the TTA group. It is concluded that TTA treatment of HFD fed mice leads to increased expression of genes involved in uptake and transport of fatty acids and HDL cholesterol in the small intestine with concomitant changes in the plasma profile of smaller lipoproteins.

Fenretinide treatment accelerates atherosclerosis development in apoE-deficient mice in spite of beneficial metabolic effects

BACKGROUND AND PURPOSE

Fenretinide, a synthetic retinoid derivative first investigated for cancer prevention and treatment, has been shown to ameliorate glucose tolerance, improve plasma lipid profile and reduce body fat mass. These effects, together with its ability to inhibit ceramide synthesis, suggest that fenretinide may have an anti-atherosclerotic action.

EXPERIMENTAL APPROACH

To this aim, nine-week-old apoE-knockout (EKO) female mice were fed for twelve weeks a Western diet, without (control) or with (0.1% w/w) fenretinide. As a reference, wild-type (WT) mice were treated similarly. Growth and metabolic parameters were monitored throughout the study. Atherosclerosis development was evaluated in the aorta and at the aortic sinus. Blood and lymphoid organs were further characterized with thorough cytological/histological and immunocytofluorimetric analyses.

KEY RESULTS

Fenretinide treatment significantly lowered body weight, glucose levels and plasma levels of total cholesterol, triglycerides, and phospholipids. In the liver, fenretinide remarkably reduced hepatic glycogenosis and steatosis driven by the Western diet. Treated spleens were abnormally enlarged, with severe follicular atrophy and massive extramedullary haematopoiesis. Severe renal hemosiderin deposition was observed in treated EKO mice. Treatment resulted in a threefold increase of total leukocytes (WT and EKO) and raised the activated/resting monocyte ratio in EKO mice. Finally, atherosclerosis development was markedly increased at the aortic arch, thoracic and abdominal aorta of fenretinide-treated mice.

CONCLUSIONS AND IMPLICATIONS

We provide the first evidence that, despite beneficial metabolic effects, fenretinide treatment may enhance the development of atherosclerosis.

Increased fatty acid oxidation and mitochondrial proliferation in liver are associated with increased plasma kynurenine metabolites and nicotinamide levels in normolipidemic and carnitine-depleted rats

Dysregulation of the tryptophan (Trp)-NAD⁺ pathway has been related to several pathological conditions, and the metabolites in this pathway are known to influence mitochondrial respiration and redox status. The aim of this project was to investigate if stimulation of beta-oxidation and mitochondrial proliferation by the mitochondrial-targeted compound 2-(tridec-12-yn-1-ylthio)acetic acid (1-triple TTA) would influence metabolites of the Trp-Kyn-NAD⁺ pathway. We wished to investigate how carnitine depletion by meldonium-treatment influenced these metabolites. After dietary treatment of male Wistar rats with 1-triple TTA for three weeks, increased hepatic mitochondrial- and peroxisomal fatty acid oxidation resulted. The plasma content of total carnitines decreased compared to control animals, whereas hepatic genes involved in CoA biosynthesis were upregulated by 1-triple TTA treatment. The plasma Trp level and individual metabolites in the kynurenine pathway were increased by 1-triple TTA, associated with decreased hepatic gene expression of indoleamine2,3-dioxygenase. 1-triple TTA treatment increased conversion of Trp to nicotinamide (Nam) as the plasma content of quinolinic acid, Nam and N1-methylnicotinamide (mNam) increased, accompanied with suppression of hepatic gene expression of α-amino-α-carboxymuconate-ε-semialdehyde decarboxylase. A positive correlation between mitochondrial fatty acid oxidation and Trp-derivatives was found. Almost identical results were obtained by 1-triple TTA in the presence of meldonium, which alone exerted minor effects. Moreover, the plasma Kyn:Trp ratio (KTR) correlated negatively to mitochondrial function. Whether increased flux through the Trp-NAD⁺ pathway increased redox status and lowered inflammation locally and systemically should be considered.

Effects of Fish n-3 PUFAs on Intestinal Microbiota and Immune System

Studies over several decades have documented the beneficial actions of n-3 polyunsaturated fatty acids (PUFAs), which are plentiful in fish oil, in different disease states. Mechanisms responsible for the efficacy of n-3 PUFAs include: (1) Reduction of triglyceride levels; (2) anti-arrhythmic and antithrombotic effects, and (3) resolution of inflammatory processes. The human microbiota project and subsequent studies using next-generation sequencing technology have highlighted that thousands of different microbial species are present in the human gut, and that there has been a significant variability of taxa in the microbiota composition among people. Several factors (gestational age, mode of delivery, diet, sanitation and antibiotic treatment) influence the bacterial community in the human gastrointestinal tract, and among these diet habits play a crucial role. The disturbances in the gut microbiota composition, i.e., gut dysbiosis, have been associated with diseases ranging from localized gastrointestinal disorders to neurologic, respiratory, metabolic, ocular, and cardiovascular illnesses. Many studies have been published about the effects of probiotics and prebiotics on the gut microbiota/microbioma. On the contrary, PUFAs in the gut microbiota have been less well defined. However, experimental studies suggested that gut microbiota, n-3 PUFAs, and host immune cells work together to ensure the intestinal wall integrity. This review discussed current evidence concerning the links among gut microbiota, n-3 PUFAs intake, and human inflammatory disease.

Topiramate protects apoE-deficient mice from kidney damage without affecting plasma lipids

Topiramate is an anticonvulsant drug also prescribed for migraine prophylaxis that acts through several mechanisms of action. Several studies indicate that topiramate induces weight loss and a moderate reduction of plasma lipids and glucose. Based on these favourable metabolic effects, aim of this study was to evaluate if topiramate could modulate atherosclerosis development and protect target organs of dysmetabolic conditions. Thirty apoE-deficient mice were divided into three groups and fed for 12 weeks a high fat diet (Control) or the same diet containing topiramate at 0.125% and 0.250%. Body weight, water and food intake were monitored throughout the study. Plasma lipids and glucose levels were measured and a glucose tolerance test was performed. Atherosclerosis development was evaluated in the whole aorta and at the aortic sinus. Histological analysis of liver, kidney and adipose tissue was performed. Topiramate did not affect weight gain and food intake. Glucose tolerance and plasma lipids were not changed and, in turn, atherosclerosis development was not different among groups. Topiramate did not modify liver and adipose tissue histology. Conversely, in the kidneys, the treatment reduced the occurrence of glomerular lipidosis by decreasing foam cells accumulation and reducing the expression of inflammatory markers. Blood urea nitrogen levels were also reduced by treatment. Our results indicate that topiramate does not affect atherosclerosis development, but preserves kidney structure and function. The study suggests that topiramate could be investigated in drug repurposing studies for the treatment of glomerular lipidosis.

Effects of Vegetable Proteins on Hypercholesterolemia and Gut Microbiota Modulation

Risk assessment tools, i.e., validated risk prediction algorithms, to estimate the patient's 10-year risk of developing cardiovascular disease (CVD) should be used to identify high-risk people for primary prevention. Current evidence confirms that appropriate monitoring and control of risk factors either reduces the likelihood of CVD or slows down its progression. It is thus crucial that all health professionals make appropriate use of all the available intervention strategies to control risk factors: from dietary improvement and adequate physical activity to the use of functional foods, food supplements, and drugs. The gut microbiota, which encompasses 1 × 1014 resident microorganisms, has been recently recognized as a contributing factor in the development of human disease. This review examines the effect of both some vegetable food components belong to the "protein food group" and the underexploited protein-rich hempseed on cholesterolemia and gut microbiota composition.

Effect of Dietary Components from Antarctic Krill on Atherosclerosis in apoE-Deficient Mice

SCOPE

Antarctic krill is a great source of n-3 fatty acids and high-quality proteins. Aim of the study was to evaluate the effect of Antarctic krill components on plasma lipids and atherosclerosis development.

METHODS AND RESULTS

Sixty apoEKO mice were divided into four groups and fed Western diet (CONTROL) or Western-like diets, differing for protein or fat content. Specifically, casein or fat in CONTROL was partially replaced by krill proteins (PRO), krill oil (KRILL OIL), or both (KRILL OIL+PRO). In KRILL OIL+PRO and KRILL OIL, cholesterol levels were significantly lower than in CONTROL group. Atherosclerosis in aorta of PRO, KRILL OIL and KRILL OIL+PRO was lower than in CONTROL, whereas, at the aortic sinus, atherosclerosis reduction was only observed in KRILL OIL. Liver steatosis, commonly present in CONTROL and PRO animals, was sporadic in KRILL OIL+PRO and KRILL OIL mice. Krill oil containing diets affected the expression of genes involved in cholesterol metabolism, mainly HMG-CoA reductase. No reduced systemic inflammation was found in all groups.

CONCLUSION

Krill oil containing diets were able to reduce cholesterol levels, inhibit plaque development and prevent liver damage. Krill proteins also reduced atherosclerosis development through mechanisms not involving lipid metabolism.

Design and synthesis of a mitochondria-targeting carrier for small molecule drugs

A novel mitochondria-targeting carrier QCy7HA was developed. QCy7HA transported the covalently attached doxorubicin (DOX) to mitochondria specifically. The conjugate limited the effects of P-glycoprotein (Pgp) efflux pumps of multidrug-resistant cells on DOX, indicating that diverting drugs to mitochondria is a potential promising method for treatment of drug-resistant cancers.

Mitochondria-Localized Fluorescent BODIPY-Platinum Conjugate

A convenient synthesis of a BODIPY (1,3,5,7-tetramethyl-8-(4-pyridyl)-4,4'-difluoroboradiazaindacene) labeled platinum compound (BODIPY-Pt) was developed by direct conjugation of cisplatin with the pyridine group of BODIPY. The membrane permeability and selective uptake of BODIPY-Pt in the mitochondria was studied using confocal laser scanning microscopy (CLSM). The fluorescent BODIPY-Pt conjugate showed high cellular proliferation inhibition against human cervical carcinoma (HeLa) and human breast cancer (MCF-7) cells, with half maximal inhibitory concentrations (IC50) of 27.37 and 12.14 μM, respectively. This work highlights the potential of using BODIPY labeled Pt compounds to realize the visualization of Pt distribution in living cells.