探討種子胜肽lunasin調節肥胖引起的免疫失調與代謝異常之作用

Overweight and obesity are defined as abnormal or excessive adipose tissue accumulation that may impair health. It has widely known that obesity associated low-grade inflammation plays an essential role in many chronic diseases. This kind of inflammation supports a central mechanism with its metabolic complications, such as insulin resistance, glucose intolerance, atherosclerosis, metabolic syndrome, type 2 diabetic mellitus, and some types of cancer. In adiposity, multiple immune cells such as macrophages and lymphocytes highly infiltrate in the adipose tissue and interact with metabolic disorders. Seed-derived peptide lunasin exerts several bio-functions, including chemopreventive, anti-inflammatory, anti-oxidant, anti-hyperlipidemia, and immune regulatory properties. The aim of this study is to explore the immunomodulation of lunasin in obese models in vitro and in vivo. First, obese models will be set up for in vitro study, including leptin, and adipocyte conditioned medium to mimic obese microenvironment. The result has shown that lunasin increased EL-4 T cell proliferation, and IL-2 and IL-10 productions induced by phorbol myristate acetate and ionomycin in T cells under obese models. In vivo, C57BL/6 mice were divided into five groups: low-fat diet (LF), high-fat diet (HF), lunasin intraperitoneal injection at 4 or 20 mg/kg body weight/day (HF-LL and HF-HL), and lunsin-enriched soy extract in diet (HF-DL) (107 mg lunasin/kg diet) for 8 weeks. The body weight, white adipose tissue and spleen of mice in HF group were higher than those in LF group. In contrast, the size and splenocytes number of spleen in lunasin groups were smaller than that in HF group. The proliferation of splenocytes of HF-LL group by concanavalin A (Con A) stimulation was higher compared to the HF group. Moreover, lunasin inhibited IL-6 and TNF-α secretions, and promoted IL-2 and IL-4 productions in splenocytes stimulated by the mitogen. In summary, these results indicated that lunasin regulates T cells proliferation and cytokines production in obese models both in vitro and in vivo. It is need to investigate about the mechanisms of immunomodulation of lunasin in the future.