Polyunsaturated fatty acids drive neutrophil extracellular trap formation in nonalcoholic steatohepatitis

Non-alcoholic steatohepatitis (NASH) is the hepatic manifestation of metabolic syndrome. Non-resolving inflammation, triggered by sustained accumulation of lipids, is an important driving force of NASH. Thus, unveiling metabolic immune regulation could help better understand the pathology and intervention of NASH. In this study, we found the recruitment of neutrophils is an early inflammatory event in NASH mice, following the formation of neutrophil extracellular traps (NETs). NET is an initiating factor which exacerbates inflammatory responses in macrophages. Inhibition of NETs using DNase I significantly alleviated inflammation in NASH mice. We further carried out a metabolomic study to identify possible metabolic triggers of NETs, and linoleic acid (LA) metabolic pathway was the most altered pathway. We re-analyzed published clinical data and validated that LA metabolism was highly correlated with NASH. Consistently, both LA and γ-linolenic acid (GLA) were active in triggering NETs formation by oxidative burst. Furthermore, we identified silybin, a hepatoprotective agent, as a potent NETosis inhibitor, which effectively blocked NETs formation both in vitro and in vivo. Together, this study not only provide new insights into metabolism-immune causal link in NASH progression, but also demonstrate silybin as an important inhibitor of NETs and its therapeutical potential in treating NETosis-related diseases.

Polyunsaturated Fatty Acids Mend Macrophage Transcriptome, Glycome, and Phenotype in the Patients with Neurodegenerative Diseases, Including Alzheimer's Disease

BACKGROUND

Macrophages of healthy subjects have a pro-resolution phenotype, upload amyloid-β (Aβ) into endosomes, and degrade Aβ, whereas macrophages of patients with Alzheimer's disease (AD) generally have a pro-inflammatory phenotype and lack energy for brain clearance of Aβ.

OBJECTIVE

To clarify the pathogenesis of sporadic AD and therapeutic effects of polyunsaturated fatty acids (PUFA) with vitamins B and D and antioxidants on monocyte/macrophage (MM) migration in the AD brain, MM transcripts in energy and Aβ degradation, MM glycome, and macrophage clearance of Aβ.

METHODS

We followed for 31.3 months (mean) ten PUFA-supplemented neurodegenerative patients: 3 with subjective cognitive impairment (SCI), 2 with mild cognitive impairment (MCI), 3 MCI/vascular cognitive impairment, 2 with dementia with Lewy bodies, and 7 non-supplemented caregivers. We examined: monocyte migration in the brain and a blood-brain barrier model by immunochemistry and electron microscopy; macrophage transcriptome by RNAseq; macrophage glycome by N-glycan profiling and LTQ-Orbitrap mass spectrometry; and macrophage phenotype and phagocytosis by immunofluorescence.

RESULTS

MM invade Aβ plaques, upload but do not degrade Aβ, and release Aβ into vessels, which develop cerebrovascular amyloid angiopathy (CAA); PUFA upregulate energy and Aβ degradation enzyme transcripts in macrophages; PUFA enhance sialylated N-glycans in macrophages; PUFA reduce oxidative stress and increase pro-resolution MM phenotype, mitochondrial membrane potential, and Aβ phagocytosis (p < 0.001).

CONCLUSION

Macrophages of SCI, MCI, and AD patients have interrelated defects in the transcriptome, glycome, Aβ phagocytosis, and Aβ degradation. PUFA mend macrophage transcriptome, enrich glycome, enhance Aβ clearance, and benefit the cognition of early-stage AD patients.

Low Sulfur Amino Acid, High Polyunsaturated Fatty Acid Diet Inhibits Breast Cancer Growth

Cancer cells may acquire resistance to stress signals and reprogram metabolism to meet the energetic demands to support their high proliferation rate and avoid death. Hence, targeting nutrient dependencies of cancer cells has been suggested as a promising anti-cancer strategy. We explored the possibility of killing breast cancer (BC) cells by modifying nutrient availability. We used in vitro models of BC (MCF7 and MDA-MB-231) that were maintained with a low amount of sulfur amino acids (SAAs) and a high amount of oxidizable polyunsatured fatty acids (PUFAs). Treatment with anti-apoptotic, anti-ferroptotic and antioxidant drugs were used to determine the modality of cell death. We reproduced these conditions in vivo by feeding BC-bearing mice with a diet poor in proteins and SAAs and rich in PUFAs (LSAA/HPUFA). Western blot analysis, qPCR and histological analyses were used to assess the anti-cancer effects and the molecular pathways involved. We found that BC cells underwent oxidative damage to DNA and proteins and both apoptosis and ferroptosis were induced. Along with caspases-mediated PARP1 cleavage, we found a lowering of the GSH-GPX4 system and an increase of lipid peroxides. A LSAA/HPUFA diet reduced tumor mass and its vascularization and immune cell infiltration, and induced apoptosis and ferroptotic hallmarks. Furthermore, mitochondrial mass was found to be increased, and the buffering of mitochondrial reactive oxygen species limited GPX4 reduction and DNA damage. Our results suggest that administration of custom diets, targeting the dependency of cancer cells on certain nutrients, can represent a promising complementary option for anti-cancer therapy.

Characterization and Optimization of Culture Conditions for Aurantiochytrium sp. SC145 Isolated from Sand Cay (Son Ca) Island, Vietnam, and Antioxidative and Neuroprotective Activities of Its Polyunsaturated Fatty Acid Mixture

Aurantiochytrium is a heterotrophic marine microalga that has potential industrial applications. The main objectives of this study were to isolate an Aurantiochytrium strain from Sand Cay (Son Ca) Island, Vietnam, optimize its culture conditions, determine its nutritional composition, extract polyunsaturated fatty acids (PUFAs) in the free (FFA) and the alkyl ester (FAAE) forms, and evaluate the antioxidation and neuroprotection properties of the PUFAs. Aurantiochytrium sp. SC145 can be grown stably under laboratory conditions. Its culture conditions were optimized for a dry cell weight (DCW) of 31.18 g/L, with total lipids comprising 25.29%, proteins 7.93%, carbohydrates 15.21%, and carotenoid at 143.67 µg/L of DCW. The FAAEs and FFAs extracted from Aurantiochytrium sp. SC145 were rich in omega 3-6-9 fatty acids (40.73% and 44.00% of total fatty acids, respectively). No acute or subchronic oral toxicity was determined in mice fed with the PUFAs in FFA or FAAE forms at different doses over 90 days. Furthermore, the PUFAs in the FFA or FAAE forms and their main constituents of EPA, DHA, and ALA showed antioxidant and AChE inhibitory properties and neuroprotective activities against damage caused by H₂O₂- and amyloid-ß protein fragment 25-35 (Aβ_25-35)-induced C6 cells. These data suggest that PUFAs extracted from Aurantiochytrium sp. SC145 may be a potential therapeutic target for the treatment of neurodegenerative disorders.

Docosapentaenoic Acid (DPA, 22:5n-3) Alleviates Ulcerative Colitis via Modification of Gut Microbiota and Their Metabolism

N-3 polyunsaturated fatty acids (n-3PUFA) are regarded as viable alternatives to aid the treatment of ulcerative colitis (UC). Most research focuses on eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA); little information is available about the effect of docosapentaenoic acid (DPA) on the gut microbiota and their metabolism in UC mice. In this study, the changes in gut microbiota and their metabolism in UC mice were studied through the 16S rRNA sequencing method and untargeted metabolomics. Moreover, the differential bacterial genus and differential metabolites in responding to DPA supplementation were screened through permutation test after orthogonal partial least squares discriminant analysis (OPLS-DA). The results indicated that DPA supplementation increased the diversity and altered the composition of the gut microbiota in UC mice; Akkermansia, Alistipes, Butyricicoccus, and Lactobacillus were selected as the differential bacterial genus. Supplementation of DPA also altered the fecal metabolite profile in the UC mice. Moreover, butyrate, N-carbamylglutamate (NCG), and histamine were screened as the differential metabolites. In conclusion, the regulation effect of DPA on the gut microbiota and their metabolism might be involved in the intervention mechanism of DPA in UC. More research needs to be carried out to elucidate the mechanism systematically.

Deuterium-Reinforced Polyunsaturated Fatty Acids Prevent Diet-Induced Nonalcoholic Steatohepatitis by Reducing Oxidative Stress

Background and Objectives: Oxidative stress is implicated in the progression of nonalcoholic steatohepatitis (NASH) through the triggering of inflammation. Deuterium-reinforced polyunsaturated fatty acids (D-PUFAs) are more resistant to the reactive oxygen species (ROS)-initiated chain reaction of lipid peroxidation than regular hydrogenated (H-) PUFAs. Here, we aimed to investigate the impacts of D-PUFAs on oxidative stress and its protective effect on NASH. Materials and Methods: C57BL/6 mice were randomly divided into three groups and were fed a normal chow diet, a methionine-choline-deficient (MCD) diet, and an MCD with 0.6% D-PUFAs for 5 weeks. The phenotypes of NASH in mice were determined. The levels of oxidative stress were examined both in vivo and in vitro. Results: The treatment with D-PUFAs attenuated the ROS production and enhanced the cell viability in tert-butyl hydroperoxide (TBHP)-loaded hepatocytes. Concurrently, D-PUFAs decreased the TBHP-induced oxidative stress in Raw 264.7 macrophages. Accordingly, D-PUFAs increased the cell viability and attenuated the lipopolysaccharide-stimulated proinflammatory cytokine expression of macrophages. In vivo, the administration of D-PUFAs reduced the phenotypes of NASH in MCD-fed mice. Specifically, D-PUFAs decreased the liver transaminase activity and attenuated the steatosis, inflammation, and fibrosis in the livers of NASH mice. Conclusion: D-PUFAs may be potential therapeutic agents to prevent NASH by broadly reducing oxidative stress.

Molecular Pharmacology of Inflammation Resolution in Atherosclerosis

Atherosclerosis is one of the most important problems of modern medicine as it is the leading cause of hospitalizations, disability, and mortality. The key role in the development and progression of atherosclerosis is the imbalance between the activation of inflammation in the vascular wall and the mechanisms of its control. The resolution of inflammation is the most important physiological mechanism that is impaired in atherosclerosis. The resolution of inflammation has complex, not fully known mechanisms, in which lipid mediators derived from polyunsaturated fatty acids (PUFAs) play an important role. Specialized pro-resolving mediators (SPMs) represent a group of substances that carry out inflammation resolution and may play an important role in the pathogenesis of atherosclerosis. SPMs include lipoxins, resolvins, maresins, and protectins, which are formed from PUFAs and regulate many processes related to the active resolution of inflammation. Given the physiological importance of these substances, studies examining the possibility of pharmacological effects on inflammation resolution are of interest.

Host Polyunsaturated Fatty Acids Potentiate Aminoglycoside Killing of Staphylococcus aureus

Aminoglycoside antibiotics rely on the proton motive force to enter the bacterial cell, and facultative anaerobes like Staphylococcus aureus can shift energy generation from respiration to fermentation, becoming tolerant of aminoglycosides. Following this metabolic shift, high concentrations of aminoglycosides are required to eradicate S. aureus infections, which endangers the host due to the toxicity of aminoglycosides. Membrane-disrupting molecules prevent aminoglycoside tolerance in S. aureus by facilitating passive entry of the drug through the membrane. Polyunsaturated fatty acids (PUFAs) increase membrane permeability when incorporated into S. aureus. Here, we report that the abundant host-derived PUFA arachidonic acid increases the susceptibility of S. aureus to aminoglycosides, decreasing the aminoglycoside concentration needed to kill S. aureus. We demonstrate that PUFAs and aminoglycosides synergize to kill multiple strains of S. aureus, including both methicillin-resistant and -susceptible S. aureus. We also present data showing that PUFAs and aminoglycosides effectively kill S. aureus small colony variants, strains that are particularly recalcitrant to killing by many antibiotics. We conclude that cotreatment with PUFAs, which are molecules with low host toxicity, and aminoglycosides decreases the aminoglycoside concentration necessary to kill S. aureus, lowering the toxic side effects to the host associated with prolonged aminoglycoside exposure. IMPORTANCE Staphylococcus aureus infects every niche of the human host, and these infections are the leading cause of Gram-positive sepsis. Aminoglycoside antibiotics are inexpensive, stable, and effective against many bacterial infections. However, S. aureus can shift its metabolism to become tolerant of aminoglycosides, requiring increased concentrations and/or longer courses of treatment, which can cause severe host toxicity. Here, we report that polyunsaturated fatty acids (PUFAs), which have low host toxicity, disrupt the S. aureus membrane, making the pathogen susceptible to aminoglycosides. Additionally, cotreatment with aminoglycosides is effective at killing S. aureus small colony variants, strains that are difficult to treat with antibiotics. Taken together, the data presented herein show the promise of PUFA cotreatment to increase the efficacy of aminoglycosides against S. aureus infections and decrease the risk to the human host of antibiotic-induced toxicity.

FAF1 blocks ferroptosis by inhibiting peroxidation of polyunsaturated fatty acids

Iron-dependent peroxidation of polyunsaturated fatty acids (PUFAs) leads to ferroptosis. While detoxification reactions removing lipid peroxides in phospholipids such as that catalyzed by glutathione peroxidase 4 (GPX4) protect cells from ferroptosis, the mechanism through which cells prevent PUFA peroxidation was not completely understood. We previously identified Fas-associated factor 1 (FAF1) as a protein directly interacting with free PUFAs through its UAS domain. Here we report that this interaction is crucial to protect cells from ferroptosis. In the absence of FAF1, cultured cells became sensitive to ferroptosis upon exposure to physiological levels of PUFAs, and mice developed hepatic injury upon consuming a diet enriched in PUFA. Mechanistically, we demonstrate that FAF1 assembles a globular structure that sequesters free PUFAs into a hydrophobic core, a reaction that prevents PUFA peroxidation by limiting its access to iron. Our study suggests that peroxidation of free PUFAs contributes to ferroptosis, and FAF1 acts upstream of GPX4 to prevents initiation of ferroptosis by limiting peroxidation of free PUFAs.

Effects of Oxygen Tension for Membrane Lipidome Remodeling of Cockayne Syndrome Cell Models

Oxygen is important for lipid metabolism, being involved in both enzymatic transformations and oxidative reactivity, and is particularly influent when genetic diseases impair the repair machinery of the cells, such as described for Cockayne syndrome (CS). We used two cellular models of transformed fibroblasts defective for CSA and CSB genes and their normal counterparts, grown for 24 h under various oxygen tensions (hyperoxic 21%, physioxic 5% and hypoxic 1%) to examine the fatty acid-based membrane remodeling by GC analysis of fatty acid methyl esters derived from membrane phospholipids. Overall, we first distinguished differences due to oxygen tensions: (a) hyperoxia induced a general boost of desaturase enzymatic activity in both normal and defective CSA and CSB cell lines, increasing monounsaturated fatty acids (MUFA), whereas polyunsaturated fatty acids (PUFA) did not undergo oxidative consumption; (b) hypoxia slowed down desaturase activities, mostly in CSA cell lines and defective CSB, causing saturated fatty acids (SFA) to increase, whereas PUFA levels diminished, suggesting their involvement in hypoxia-related signaling. CSB-deprived cells are the most sensitive to oxidation and CSA-deprived cells are the most sensitive to the radical-based formation of trans fatty acids (TFA). The results point to the need to finely differentiate biological targets connected to genetic impairments and, consequently, suggest the better definition of cell protection and treatments through accurate molecular profiling that includes membrane lipidomes.

Polyunsaturated Fatty Acid-Enriched Lipid Fingerprint of Glioblastoma Proliferative Regions Is Differentially Regulated According to Glioblastoma Molecular Subtype

Glioblastoma (GBM) represents one of the deadliest tumors owing to a lack of effective treatments. The adverse outcomes are worsened by high rates of treatment discontinuation, caused by the severe side effects of temozolomide (TMZ), the reference treatment. Therefore, understanding TMZ’s effects on GBM and healthy brain tissue could reveal new approaches to address chemotherapy side effects. In this context, we have previously demonstrated the membrane lipidome is highly cell type-specific and very sensitive to pathophysiological states. However, little remains known as to how membrane lipids participate in GBM onset and progression. Hence, we employed an ex vivo model to assess the impact of TMZ treatment on healthy and GBM lipidome, which was established through imaging mass spectrometry techniques. This approach revealed that bioactive lipid metabolic hubs (phosphatidylinositol and phosphatidylethanolamine plasmalogen species) were altered in healthy brain tissue treated with TMZ. To better understand these changes, we interrogated RNA expression and DNA methylation datasets of the Cancer Genome Atlas database. The results enabled GBM subtypes and patient survival to be linked with the expression of enzymes accounting for the observed lipidome, thus proving that exploring the lipid changes could reveal promising therapeutic approaches for GBM, and ways to ameliorate TMZ side effects.

Activating endogenous resolution pathways by soluble epoxide hydrolase inhibitors for the management of COVID-19

Anti-inflammatory, specialized proresolving mediators such as resolvins, protectins, maresins, and lipoxins derived from polyunsaturated acids may play a potential role in lung diseases as they protect different organs in animal disease models. Polyunsaturated fatty acids are an important resource for epoxy fatty acids (EET, EEQ, and EDP) that mediate a broad array of anti-inflammatory and proresolving mechanisms, such as mitigation of the cytokine storm. However, epoxy fatty acids are rapidly metabolized by soluble epoxide hydrolase (sEH). In animal studies, administration of sEH inhibitors (sEHIs) increases epoxy fatty acid levels, reduces lung inflammation, and improves lung function, making it a viable COVID-19 treatment approach. Thus, using sEHIs to activate endogenous resolution pathways might be a novel method to minimize organ damage in severe cases and improve outcomes in COVID-19 patients. This review focuses on the use of sEH inhibitors to activate endogenous resolution mechanisms for the treatment of COVID-19.

The docosahexaenoic acid derivatives, diHEP-DPA and TH-DPA, synthesized via recombinant lipoxygenase, ameliorate disturbances in lipid metabolism and liver inflammation in high fat diet-fed mice

7S,15R-Dihydroxy-16S,17S-epoxy-docosapentaenoic acid (diHEP-DPA) and 7S,15R,16S,17S-tetrahydroxy-docosapentaenoic acid (TH-DPA) are two novel lipid mediators derived from docosahexaenoic acid (DHA) that we previously synthesized via combined enzymatic and chemical reactions. In the present study, we investigated the effects of these compounds on disturbances in lipid metabolism and liver inflammation induced by a high fat diet (HFD) in mice. Male BALB/c mice were randomly divided into four groups (n = 10/group): controls, HFD only, HFD + diHEP-DPA, and HFD + TH-DPA. Mice in HFD + diHEP-DPA and HFD + TH-DPA groups were orally administered 20 μg/kg of diHEP-DPA or TH-DPA, respectively. Measurements of adipose accumulation and liver inflammation showed that both diHEP-DPA and TH-DPA decreased adipose tissue mass and liver color depth, as well as total cholesterol, triglycerides, and low-density lipoprotein-cholesterol in the serum of HFD-fed mice compared with mice in the HFD-only group, while elevating high-density lipoprotein-cholesterol. Both of them also decreased hepatic expression of genes encoding lipid synthesis-related proteins (PPARγ, SIRT1, SREBP-1c and FASN) and increased the expression of genes encoding proteins involved in lipid degradation (PPARα and CPT-1) in the liver. Western blotting and quantitative RT-PCR confirmed that diHEP-DPA or TH-DPA administration modulated the expression of inflammation-related genes (TNF-α and IL-6) and inhibited activation of the NF-κB signaling pathway in livers of HFD-fed mice. Taken together, our data indicate that diHEP-DPA and TH-DPA ameliorate liver inflammation and inhibit HFD-induced obesity in mice.

Bioprospecting of Microalgae Isolated from the Adriatic Sea: Characterization of Biomass, Pigment, Lipid and Fatty Acid Composition, and Antioxidant and Antimicrobial Activity

Marine microalgae and cyanobacteria are sources of diverse bioactive compounds with potential biotechnological applications in food, feed, nutraceutical, pharmaceutical, cosmetic and biofuel industries. In this study, five microalgae, Nitzschia sp. S5, Nanofrustulum shiloi D1, Picochlorum sp. D3, Tetraselmis sp. Z3 and Tetraselmis sp. C6, and the cyanobacterium Euhalothece sp. C1 were isolated from the Adriatic Sea and characterized regarding their growth kinetics, biomass composition and specific products content (fatty acids, pigments, antioxidants, neutral and polar lipids). The strain Picochlorum sp. D3, showing the highest specific growth rate (0.009 h⁻¹), had biomass productivity of 33.98 ± 0.02 mg L⁻¹ day⁻¹. Proteins were the most abundant macromolecule in the biomass (32.83–57.94%, g g⁻¹). Nanofrustulum shiloi D1 contained significant amounts of neutral lipids (68.36%), while the biomass of Picochlorum sp. D3, Tetraselmis sp. Z3, Tetraselmis sp. C6 and Euhalothece sp. C1 was rich in glycolipids and phospholipids (75%). The lipids of all studied microalgae predominantly contained unsaturated fatty acids. Carotenoids were the most abundant pigments with the highest content of lutein and neoxanthin in representatives of Chlorophyta and fucoxanthin in strains belonging to the Bacillariophyta. All microalgal extracts showed antioxidant activity and antimicrobial activity against Gram-negative E. coli and S. typhimurium and Gram-positive S. aureus.

Histone deacetylase inhibitor 2-hexyl-4-pentynoic acid enhances hydroxyurea therapeutic effect in triple-negative breast cancer cells

Triple-negative breast cancer (TNBC) treatment has only limited effect, and it causes a significant number of deaths. Histone deacetylase inhibitors (HDACis) are emerging as promising anti-tumor agents in many types of cancers. We thus hypothesized that 2-hexyl-4-pentynoic acid (HPTA), a novel HDACi, could sensitize TNBC to hydroxyurea (HU, a ribonucleotide reductase inhibitor). In the present study, we investigated the effect of HPTA, alone or in combination with HU on cell survival, DNA double-strand breaks (DSBs), key homologous recombination (HR) repair proteins and cell cycle progression in MDA-MB-468 and MDA-MB-231 human TNBC cell lines. HPTA and HU synergistically inhibited the survival of TNBC cell lines and resulted in the accumulation of DNA double-strand breaks (DSBs). HPTA can sensitize TNBC cells to HU by inhibiting replication protein A2 (RPA2) hyperphosphorylation-mediated HR repair, and lessen cell accumulation in S-phase by inhibiting ATR-CHK1 signaling pathway. Taken together, our data suggested that HPTA enhances HU therapeutic effect by blocking the HR repair and regulating cell cycle progression in TNBC.

Influence of Polyunsaturated Fatty Acid Intake on Kidney Functions of Rats with Chronic Renal Failure

Arachidonic acid (ARA), an omega-6 (ω-6) polyunsaturated fatty acid (PUFA), is involved in the development and maintenance of renal functions, whereas docosahexaenoic acid (DHA) is an omega-3 (ω-3) PUFA that has anti-inflammatory effects and attenuates nephropathy. However, their effects on the progression of chronic kidney disease (CKD) remain unknown. The aim of this study was to assess the effects of feeding ARA, DHA, and ARA and DHA-containing diets on rats with 5/6 nephrectomized kidneys. Urine and feces were collected every 4 weeks, and the kidneys were collected at 16 weeks after surgery. Urinary albumin (U-ALB) excretion increased gradually with nephrectomy, but the U-ALB excretion was attenuated by feeding the rats with an ARA + DHA-containing diet. Reactive oxygen species (ROS) levels in the kidneys were lower in the ARA + DHA group than in the other groups. At 4 weeks after surgery, the lipid peroxide (LPO) levels in the plasma of the ARA + DHA groups decreased significantly after surgery compared to the control CKD group, but this did not happen at 16 weeks post-surgery. There was a significant negative correlation between LPO levels in the plasma at 4 weeks and creatinine clearance, and a positive correlation with urinary albumin levels. These results suggest that the combination of ARA and DHA inhibit the progress of early stage CKD.

Effects of Nutrition on Cognitive Function in Adults with or without Cognitive Impairment: A Systematic Review of Randomized Controlled Clinical Trials

New dietary approaches for the prevention of cognitive impairment are being investigated. However, evidence from dietary interventions is mainly from food and nutrient supplement interventions, with inconsistent results and high heterogeneity between trials. We conducted a comprehensive systematic search of randomized controlled trials (RCTs) published in MEDLINE-PubMed, from January 2018 to July 2021, investigating the impact of dietary counseling, as well as food-based and dietary supplement interventions on cognitive function in adults with or without cognitive impairment. Based on the search strategy, 197 eligible publications were used for data abstraction. Finally, 61 articles were included in the analysis. There was reasonable evidence that dietary patterns, as well as food and dietary supplements improved cognitive domains or measures of brain integrity. The Mediterranean diet showed promising results, whereas the role of the DASH diet was not clear. Healthy food consumption improved cognitive function, although the quality of these studies was relatively low. The role of dietary supplements was mixed, with strong evidence of the benefits of polyphenols and combinations of nutrients, but with low evidence for PUFAs, vitamin D, specific protein, amino acids, and other types of supplements. Further well-designed RCTs are needed to guide the development of dietary approaches for the prevention of cognitive impairment.

ω-3 DPA Protected Neurons from Neuroinflammation by Balancing Microglia M1/M2 Polarizations through Inhibiting NF-κB/MAPK p38 Signaling and Activating Neuron-BDNF-PI3K/AKT Pathways

Microglia M1 phenotype causes HPA axis hyperactivity, neurotransmitter dysfunction, and production of proinflammatory mediators and oxidants, which may contribute to the etiology of depression and neurodegenerative diseases. Eicosapentaenoic acid (EPA) may counteract neuroinflammation by increasing n-3 docosapentaenoic acid (DPA). However, the cellular and molecular mechanisms of DPA, as well as whether it can exert antineuroinflammatory and neuroprotective effects, are unknown. The present study first evaluated DPA’s antineuroinflammatory effects in lipopolysaccharide (LPS)-activated BV2 microglia. The results showed that 50 μM DPA significantly decreased BV2 cell viability after 100 ng/mL LPS stimulation, which was associated with significant downregulation of microglia M1 phenotype markers and proinflammatory cytokines but upregulation of M2 markers and anti-inflammatory cytokine. Then, DPA inhibited the activation of mitogen-activated protein kinase (MAPK) p38 and nuclear factor-κB (NF-κB) p65 pathways, which results were similar to the effects of NF-κB inhibitor, a positive control. Second, BV2 cell supernatant was cultured with differentiated SH-SY5Y neurons. The results showed that the supernatant from LPS-activated BV2 cells significantly decreased SH-SY5Y cell viability and brain-derived neurotrophic factor (BDNF), TrkB, p-AKT, and PI3K expression, which were significantly reversed by DPA pretreatment. Furthermore, DPA neuroprotection was abrogated by BDNF-SiRNA. Therefore, n-3 DPA may protect neurons from neuroinflammation-induced damage by balancing microglia M1 and M2 polarizations, inhibiting microglia-NF-κB and MAPK p38 while activating neuron-BDNF/TrkB-PI3K/AKT pathways.

2-Hexyl-4-Pentylenic Acid (HPTA) Stimulates the Radiotherapy-induced Abscopal Effect on Distal Tumor through Polarization of Tumor-associated Macrophages

OBJECTIVE

The aim of this study was to explore the effects of 2-hexyl-4-pentylenic acid (HPTA) in combination with radiotherapy (RT) on distant unirradiated breast tumors.

METHODS

Using a rat model of chemical carcinogen (7,12-dimethylbenz[a]anthracene,DMBA)-induced breast cancer, tumor volume was monitored and treatment response was evaluated by performing HE staining, immunohistochemistry, immunofluorescence, qRT-PCR, and western blot analyses.

RESULTS

The results demonstrated that HPTA in combination with RT significantly delayed the growth of distant, unirradiated breast tumors. The mechanism of action included tumor-associated macrophage (TAM) infiltration into distant tumor tissues, M1 polarization, and inhibition of tumor angiogenesis by IFN-γ.

CONCLUSION

The results suggest that the combination of HPTA with RT has an abscopal effect on distant tumors via M1-polarized TAMs, and HPTA may be considered as a new therapeutic for amplifying the efficacy of local RT for non-targeted breast tumors.

The graphical abstract was available in the web of www.besjournal.com.

The MS Remyelinating Drug Bexarotene (an RXR Agonist) Promotes Induction of Human Tregs and Suppresses Th17 Differentiation In Vitro

The retinoid X receptor agonist bexarotene promotes remyelination in patients with multiple sclerosis. Murine studies have also demonstrated that RXR agonists have anti-inflammatory effects by enhancing the ability of all-trans-retinoic acid (atRA) to promote T-regulatory cell (Treg) induction and reduce Th17 differentiation in vitro. By stimulating human naïve CD4 T-cells in the presence of Treg or Th17 skewing cytokines, we show that bexarotene also tips the human Treg/Th17 axis in favor of Treg induction, but unlike murine cells this occurs independently of atRA and retinoic acid receptor signaling. Tregs induced in the presence of bexarotene express canonical markers of T-regulation and are functionally suppressive in vitro. Circulating Treg numbers did not increase in the blood of trial patients receiving bexarotene; we believe this is because Treg induction is likely to occur within tissues. These findings lend support to developing RXR agonists as treatments of autoimmune diseases, in particular multiple sclerosis.

Review of Biological Effects of Acute and Chronic Radiation Exposure on Caenorhabditis elegans

Knowledge regarding complex radiation responses in biological systems can be enhanced using genetically amenable model organisms. In this manuscript, we reviewed the use of the nematode, Caenorhabditis elegans (C. elegans), as a model organism to investigate radiation’s biological effects. Diverse types of experiments were conducted on C. elegans, using acute and chronic exposure to different ionizing radiation types, and to assess various biological responses. These responses differed based on the type and dose of radiation and the chemical substances in which the worms were grown or maintained. A few studies compared responses to various radiation types and doses as well as other environmental exposures. Therefore, this paper focused on the effect of irradiation on C. elegans, based on the intensity of the radiation dose and the length of exposure and ways to decrease the effects of ionizing radiation. Moreover, we discussed several studies showing that dietary components such as vitamin A, polyunsaturated fatty acids, and polyphenol-rich food source may promote the resistance of C. elegans to ionizing radiation and increase their life span after irradiation.

Polar Lipids Composition, Antioxidant and Anti-Inflammatory Activities of the Atlantic Red Seaweed Grateloupia turuturu

Grateloupia turuturu Yamada, 1941, is a red seaweed widely used for food in Japan and Korea which was recorded on the Atlantic Coast of Europe about twenty years ago. This seaweed presents eicosapentaenoic acid (EPA) and other polyunsaturated fatty acids (PUFAs) in its lipid fraction, a feature that sparked the interest on its potential applications. In seaweeds, PUFAs are mostly esterified to polar lipids, emerging as healthy phytochemicals. However, to date, these biomolecules are still unknown for G. turuturu. The present work aimed to identify the polar lipid profile of G. turuturu, using modern lipidomics approaches based on high performance liquid chromatography coupled to high resolution mass spectrometry (LC-MS) and gas chromatography coupled to mass spectrometry (GC-MS). The health benefits of polar lipids were identified by health lipid indices and the assessment of antioxidant and anti-inflammatory activities. The polar lipids profile identified from G. turuturu included 205 lipid species distributed over glycolipids, phospholipids, betaine lipids and phosphosphingolipids, which featured a high number of lipid species with EPA and PUFAs. The nutritional value of G. turuturu has been shown by its protein content, fatty acyl composition and health lipid indices, thus confirming G. turuturu as an alternative source of protein and lipids. Some of the lipid species assigned were associated to biological activity, as polar lipid extracts showed antioxidant activity evidenced by free radical scavenging potential for the 2,2'-azino-bis-3-ethyl benzothiazoline-6-sulfonic acid (ABTS^●+) radical (IC₅₀ ca. 130.4 μg mL^-1) and for the 2,2-diphenyl-1-picrylhydrazyl (DPPH^●) radical (IC₂₅ ca. 129.1 μg mL^-1) and anti-inflammatory activity by inhibition of the COX-2 enzyme (IC₅₀ ca. 33 µg mL^-1). Both antioxidant and anti-inflammatory activities were detected using a low concentration of extracts. This integrative approach contributes to increase the knowledge of G. turuturu as a species capable of providing nutrients and bioactive molecules with potential applications in the nutraceutical, pharmaceutical and cosmeceutical industries.

Chemical Characterization, Antiproliferative and Antioxidant Activities of Polyunsaturated Fatty Acid-Rich Extracts from Chlorella sp. S14

Microalgae is a rich source of polyunsaturated fatty acid. This study was conducted to identify and isolate microalgal strain with the potentials for producing polyunsaturated fatty acids (PUFAs) and determine its cytotoxic effect on some cancer cells. The algal strain (Chlorella sp. S14) was cultivated using modified BG-11 media, and algal biomass obtained was used for fatty acid extraction. Gas chromatographic–mass spectrometry was used to identify and quantify the levels of the fatty acid constituents. The total content of monounsaturated fatty acids (1.12%) was low compared to polyunsaturated fatty acids (PUFAs) (52.87%). Furthermore, n-3 PUFAs accounted for (12.37%) of total PUFAs with the presence of α-linolenic acid (2.16%) and cis-11,14,17-eicosatrienoic acid (2.16%). The PUFA-rich extract did not exhibit a cytotoxic effect on normal cells. Treatment with the PUFA-rich extract (150 µg/mL) significantly reduced cell viability in MCF-7 (31.58%) and A549 (62.56%) cells after the 48 h treatment. Furthermore, treatment of MCF-7 with fatty acid extracts (125 and 150 µg/mL) showed a significant reduction in MDA levels, increase in catalase activities and decrease in GSH level compared to untreated cells. However, a slight decrease in MDA level was observed in A549 cells after the 48 h treatment. There are no significant changes in catalase activities and GSH level in treated A549 cells. However, a slight reduction of NO levels was observed in treated MCF-7 and A549 cells. These results indicate the potentials of PUFA-rich extracts from Chlorella sp. S14 to reduce viability and modulate redox status in A549 and MCF-7 cells.

Diets enriched in PUFAs at an early postimplantation stage prevent embryo resorptions and impaired mTOR signaling in the decidua from diabetic rats

Maternal diabetes increases the risk of embryo resorptions and impairs embryo development. Decidualization is crucial for embryo development and regulated by mTOR signaling. However, little is known about how maternal diabetes affects the decidua at early postimplantation stages and whether dietary treatments enriched in polyunsaturated fatty acids (PUFAs) can prevent decidual alterations. Here, we determined resorption rates, decidual mTOR pathways and markers of decidual function and remodeling in diabetic rats fed or not with diets enriched in PUFAs exclusively during the early postimplantation period. Pregestational streptozotocin-induced diabetic Albino Wistar rats and controls were fed or not with diets enriched in 6% sunflower oil or 6% chia oil (enriched in n-6 or n-3 PUFAs, respectively) on days 7, 8 and 9 of pregnancy and evaluated on day 9 of pregnancy. Maternal diabetes induced an 11-fold increase in embryo resorptions, which was prevented by both PUFAs-enriched diets despite no changes in maternal glycemia. The activity of mTOR pathway was decreased in the decidua from diabetic rats, an alteration prevented by the PUFAs-enriched diets. PUFAs-enriched diets prevented increased expression of Foxo1 (a negative regulator of mTOR) and reduced expression of miR-21 (a negative regulator of Foxo1). These diets also prevented reduced markers of decidual function (leukemia inhibitory factor and IGFBP1 expression and MMPs activity) in diabetic rat decidua. We identified the early post implantation as a crucial stage for pregnancy success, in which dietary PUFAs can protect diabetic pregnancies from embryo resorptions, decidual mTOR signaling impairments, and altered markers of decidual function and remodeling.

Effect of 6,9,12,15-Hexadecatetraenoic Acid (C16:4n-1)-Ethyl Ester on Lipid Content and Fatty Acid Composition in the Blood and Organs of Mice

The effects of 6,9,12,15-hexadecatetraenoic acid (C16:4n-1, HDTA), an n-1 polyunsaturated fatty acid (FA), on plasma and liver lipid content and distribution in blood and tissues were investigated. Mice were fed experimental diets containing 10% HDTA or eicosapentaenoic acid in ethyl ester form based on corn oil for four weeks. Dietary HDTA intake lowered plasma triacylglycerol content without affecting plasma total cholesterol content. HDTA barely accumulated in the epididymal white adipose tissue (eWAT), while C18:4n-1, an HDTA metabolite, was detected in small amounts (< 1% of total FAs) in the plasma, liver, and eWAT.