Immune-Enhancement and Anti-Inflammatory Activities of Fatty Acids Extracted from Halocynthia aurantium Tunic in RAW264.7 Cells

Abstract

Halocynthia aurantium, an edible ascidian species, has not been studied scientifically, even though tunicates and ascidians are well-known to contain several unique and biologically active materials. The current study investigated the fatty acid profiles of the H. aurantium tunic and its immune-regulatory effects on RAW264.7 macrophage cells. Results of the fatty acid profile analysis showed a difference in ratios, depending on the fatty acids being analysed, including those of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA). In particular, omega-3 fatty acids, such as eicosatrienoic acid n-3 (ETA n-3), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), were much higher than omega-6 fatty acids. Moreover, the H. aurantium tunic fatty acids, significantly and dose-dependently, increased the NO and prostaglandin E2 (PGE2) production in RAW264.7 cells, for immune-enhancement without cytotoxicity. In addition, these fatty acids regulated the transcription of immune-associated genes, including iNOS, IL-1β, IL-6, COX-2, and TNF-α. These actions were activated and deactivated via Mitogen-activated protein kinase (MAPK)and NF-κB signaling, to regulate the immune responses. Conversely, the H. aurantium tunic fatty acids effectively suppressed the inflammatory cytokine expressions, including iNOS, IL-1β, IL-6, COX-2, and TNF-α, in LPS-stimulated RAW264.7 cells. Productions of COX-2 and PGE2, which are key biomarkers for inflammation, were also significantly reduced. These results elucidated the immune-enhancement and anti-inflammatory mechanisms of the H. aurantium tunic fatty acids in macrophage cells. Moreover, the H. aurantium tunic might be a potential fatty acid source for immune-modulation.

Screening for Health-Promoting Fatty Acids in Ascidians and Seaweeds Grown under the Influence of Fish Farming Activities

“…The higher levels of n -3 FAs present in the −Org resulted in a higher n -3/ n -6 ratio, with FAs 18:4 n -3, EPA, and DHA being the main contributors to this trend. This finding is consistent with Monmai et al [ 35 ], as these authors verified that in the edible ascidian Halocynthia aurantium n -3 FAs were present in much higher levels than n -6 FAs. Likewise, Zhao and Li [ 37 ] documented that tunics and inner body tissues of ascidians Halocynthia roretzi , Styela plicata , Ascidia sp.…”

“…Knowledge on ascidians’ FA profiling is still poorly explored. However, some studies have already confirmed that ascidians present a high n -3/ n -6 ratio [ 3 , 35 ] and high values of EPA and DHA [ 36 ], establishing ascidians as a potential new bioresource for n -3 fatty acids-rich marine lipids [ 3 , 37 , 38 ]. Hassanzadeh [ 38 ] concluded that the FA profile of ascidians presented similar values to that of fish oil and, therefore, considered ascidians as a good alternative for fish oil in the formulation of aquafeeds.…”

A Study on the Therapeutic Efficacy of San Zi Yang Qin Decoction for Non-Alcoholic Fatty Liver Disease and the Underlying Mechanism Based on Network Pharmacology

“…TNF- α is also involved in lipid metabolism. It stimulates the release of free fatty acid (FFA), which in turn promotes the release of TNF- α from macrophages, eventually enhancing lipid accumulation in the liver [ 52 , 53 ]. By directly targeting the intracellular insulin signal transduction system, TNF- α can enhance insulin resistance through upregulating suppressor of cytokine signaling 3 (SOCS-3) [ 54 ] and inhibiting adiponectin activity [ 55 ].…”

Anti-Inflammatory Effects of Fermented Lotus Root and Linoleic Acid in Lipopolysaccharide-Induced RAW 264.7 Cells

“…Total volume of real-time RT-PCR reaction mixture was 20 μL with a 96-well format, included 5.5 μL cDNA template, 2 μL primer mixture (10 μM, 1 μL forward and reverse primer each), 2.5 μL DEPC-treated water, 10 μL TB Green ® Premix Ex Taq™ II (Takara Bio Inc., Kusatsu, Shiga, Japan). All primers were obtained from Macrogen (Seoul, Korea), and sequences were referenced from Chaiwat Monmai et al [ 36 ]. The primer sequences used are shown in Table 1 .…”