Seed peptide lunasin ameliorates obesity-induced inflammation and regulates immune responses in C57BL/6J mice fed high-fat diet.

Obesity causes immune cells to infiltrate into adipose tissues and secrete proinflammatory mediators, promoting the development of chronic diseases. The seed peptide lunasin has been reported to have several bioactivities. We aimed to investigate the immunomodulatory properties of lunasin in obese models. Female and male C57BL/6J mice were divided into three groups: low-fat diet (LF), high-fat diet (HF), and HF with an intraperitoneal injection of lunasin (HFL). In females, lunasin decreased the levels of monocyte chemoattractant protein-1 (MCP-1), interleukin (IL)-1ß, and tumor necrosis factor (TNF-α) produced in peritoneal macrophages, indicating a decrease in F4/80+ macrophage infiltration, especially the CD11c + M1 phenotype. Serum leptin and tissue-oxidized lipid malondialdehyde levels were decreased in the HFL group. In males, lunasin normalized the obesity-induced increase in spleen size and splenocyte numbers. Moreover, lunasin inhibited IL-6 secretion while promoting interferon gamma (IFN-γ) and IL-2 production in the splenocytes. In vitro, lunasin increased EL-4 T-cell proliferation and IL-2 production in activated T cells under obese conditions. Thus, lunasin is a potential natural compound that promotes immunomodulation in both female and male obese mice in a sex-dependent manner. Furthermore, lunasin mediates the anti-inflammatory response and enhances the T helper type 1 cell response to obesity-related immune disorders.

Obesity enhances carcinogen 7, 12-Dimethylbenz [a] anthracene -induced tumorigenesis in vitro and in vivo.

Growing body of evidence shows that extra adiposity influences on the progression of multiple cancers, including breast cancer. The aim of this study is to investigate whether obesity correlates with mammary tumor development in vitro and in vivo. We found that obesity-related mediators, 3T3-L1 adipocyte conditioned medium, enhanced formation of cancerous foci induced by the carcinogen 7,12-Dimethylbenz[a]anthracene (DMBA) in NIH/3T3 fibroblasts, in vitro. Additionally, we tested the effect of obesity in mouse model of DMBA-induced breast cancer. C57BL/6J female mice were fed a low fat (LF), or high fat (HF) diet, and DMBA was administered by oral gavage (LF plus DMBA [LFD] and HF plus DMBA [HFD]). Our results indicated that HFD mouse developed a tumor which weight was 169mg, whereas the LFD mouse developed a tumor weight of 77mg. Histological analysis of the mammary tumor from HFD group showed morphological aggressiveness and multiple cell type infiltration compared to LFD group. The epididymal adipose tissue from the DMBA groups showed more macrophage infiltration, polarized towards an M1 phenotype compared to the non-DMBA mice. HF mice showed less accumulation of M2 macrophages in the adipose tissue. In summary, obese mediators enhanced DMBA induced tumorigenesis in vitro and in vivo.

Lunasin attenuates obesity-related inflammation in RAW264.7 cells and 3T3-L1 adipocytes by inhibiting inflammatory cytokine production.

Obesity has become a major threat to public health and is accompanied by chronic low-grade inflammation, which leads to various pathological developments. Lunasin, a natural seed peptide, exhibits several biological activities, such as anti-carcinogenesis, anti-inflammatory, and antioxidant activities. However, the mechanism of action of lunasin in obesity-related inflammation has not been investigated. The aim of this study was to explore whether lunasin could reduce the inflammation induced by obesity-related mediators in RAW264.7 cells and 3T3-L1 adipocytes and whether it could attenuate the crosstalk between the two cell lines. RAW264.7 cells were cultured in leptin-containing medium, adipocyte-conditioned medium (Ad-CM), or co-cultured with 3T3-L1 cells to mimic the physiology of obesity. The data showed that the secretion of pro-inflammatory cytokine interleukin-1ß (IL-1ß) was inhibited by lunasin after leptin activation of RAW264.7 cells. In addition, lunasin decreased monocyte chemoattractant protein-1 (MCP-1) and IL-1ß secretions in the Ad-CM model. Cytokine MCP-1, IL-6, tumor necrosis factor (TNF)-α, and IL-1ß secretions were significantly decreased by leptin or Ad-CM plus lipopolysaccharide stimulation. Subsequently, the co-culture of the two cells refined the direct relation between them, resulting in apparently increased MCP-1, and decreased IL-6 levels after lunasin treatment. In 3T3-L1 adipocytes, lunasin also exhibited anti-inflammatory property by inhibiting MCP-1, plasminogen activator inhibitor-1, and leptin productions stimulated by (TNF)-α, lipopolysaccharide, or RAW264.7 cell-conditioned medium. This result revealed that lunasin acts as a potential anti-inflammatory agent not only in macrophages but also in adipocytes, disrupting the crosstalk between these two cells. Therefore, this study suggests the intake of lunasin from diet or as a supplement, for auxiliary prevention or therapy in obesity-related inflammatory applications.