Biodistribution and immunomodulatory activities of a proteoglycan isolated from Ganoderma lucidum

A proteoglycan, namely FYGL extracted from Ganoderma lucidum, was proved previously efficient for anti-diabetes in vivo. However, many medicine functions of FYGL have not been revealed, such as immunoregulation, an important function of Ganoderma in the traditional Chinese medicine. In this work, we firstly investigated the distribution of FYGL orally administrated by mice and found that FYGL was available in small intestine and viscera organs and enriched mostly in liver. Consequently, we studied the immunoregulation mechanism of FYGL in RAW 264.7 macrophages. The results showed that FYGL could induce initially ROS and trigger Ca2+ ions influx into cells, leading to the activation of NF-KB and MAPK signaling to secret NO and cytokines for immune responses, and the promotion of phagocytosis. Meanwhile, FYGL absorbed in cells could reduce ROS, therefore preventing mitochondrial membrane from damage for cells safety. The results provided the immunoregulation basis of FYGL potentially applicable in clinics.