Inhibitory effect of fucoidan on TNF-α-induced inflammation in human retinal pigment epithelium cells

Abstract

Sargassum horneri (S. horneri) is a brown seaweed that contains a fucose-rich sulfated polysaccharide called fucoidan and is known to possess beneficial bioactivities, such as anti-inflammatory, antiviral, antioxidative, and antitumoral effects. This study aimed to determine the anti-inflammatory effects of AB_SH (hydrothermal extracts from S. horneri) and its bioactive compound (fucoidan) against tumor necrosis factor alpha (TNF-α)-induced inflammation in human retinal pigment epithelial (RPE) cells. AB_SH did not exhibit any cytotoxicity, and it decreased the mRNA expression of interleukin (IL)-6 and IL-8 and the production of the cytokines IL-6 and TNF-α. It also suppressed the expression levels of phosphorylated nuclear factor kappa B (NF-κB) and mitogen-activated protein kinases (MAPKs), including c-Jun amino-terminal kinases (JNK), p38 protein kinases (p38), and extracellular signal-regulated kinase (ERK) proteins, suggesting that AB_SH inhibits activation of the NF-kB/MAPK signaling pathway. Since fucoidan was identified in the composition analysis of AB_SH, it was additionally shown to be required for its anti-inflammatory effects in TNF-α-stimulated human RPE cells. In line with the AB_SH results, fucoidan reduced the mRNA levels of IL-6, IL-1ß, and IL-8 and production of the cytokines IL-6, TNF-α, and IL-8 through the downregulation of the NF-kB/MAPK signaling pathway in a dose-dependent manner. Collectively, the ability of AB_SH from S. horneri hydrothermal extracts to reduce inflammation indicates that it may be a good functional ingredient for managing ocular disorders.

Loliolide in Sargassum horneri Alleviates Ultrafine Urban Particulate Matter (PM 0.1)-Induced Inflammation in Human RPE Cells

“…Additionally, in our previous study, we confirmed that fucoidan has an anti-inflammatory effect against inflammation induced by TNF-α in ARPE-19 cells. Compared to these results, loliolide reduced chemokine secretion more than fucoidan [ 14 ].…”

“…ARPE-19 cells were seeded into 12-well plates at a density of 1 × 10 5 cells/well and incubated for 24 h. After incubation, uf-UPs (0.1, 1, and 10 µg/mL) or loliolide (25,50,100,200, and 400 µM) was added at the indicated concentrations, and cells were further incubated for 24 h at 37 • C in humidified air with 5% CO 2 . The concentration of S. horneri was determined based on previous studies [14]. A stock solution of MTT (5 mg/mL in PBS) was added to each well at a final concentration of 0.5 mg/mL according to the manufacturer's protocol.…”

“…Sargassum horneri (S. horneri) is a well-known brown alga commonly inhabiting the coast of Japan and Korea that is reported to exhibit various biological activities such as anti-inflammatory, anti-apoptotic and anti-allergic effects [ 9 , 10 , 11 , 12 ]. According to many studies, the main components of S. horneri mainly consist of polyphenols and carbohydrates [ 13 , 14 ]. S. horneri contains bioactive compounds, such as fucoidan and loliolide, with promising bioactivities, such as antioxidant and anti-inflammatory functions [ 15 ].…”

“…Furthermore, many studies have suggested that S. horneri is a potential inhibitor of PM-induced inflammatory responses, oxidative stress, and cell death [ 19 , 20 ]. We previously reported that fucoidan exhibits anti-inflammatory effects by suppressing the inflammatory response of TNF-α-stimulated ARPE-19 cells [ 14 ]. In particular, TNF-α, which is one of the key regulators of the PM-induced inflammatory response, is not only associated with dry eye syndrome and corneal epithelium inflammation but is also known to cause allergic immune responses that lead to the development of ocular allergy [ 8 , 21 ].…”

Natural products in atherosclerosis therapy by targeting PPARs: a review focusing on lipid metabolism and inflammation

“…For instance, Tibetan burnip polysaccharide reduces the expression of ICAM-1, VCAM-1, IL-6, IL-1β, and TNF-α partially by downregulating PPARγ in hyperlipidemic rats ( 203 ). Moreover, intake of low dose sucrose (7.5 mg/ml) is found to activate PPARγ via restoring microbial dysfunction and upregulating SCFAs levels, thereby suppressing MAPK/NF-κB signaling pathway, while high dose sucrose (30 mg/ml) exacerbates DSS-induced colitis ( 204 ). Additionally, Astragalus polysaccharide inhibits protein kinase A/p38 MAPK signaling pathway and the expression of PPARγ and PGC-1α, suppressing inflammation in heart failure rats ( 190 ).…”