Chih-Yao Chung1, Wen-Chin Yang2, Chih-Lung Liang3, Hsien-Yueh Liu1, Shih-Kai Lai1, Cicero Lee-Tian Chang4. 1. Department of Veterinary Medicine, National Chung Hsing University, Taichung 402, Taiwan. 2. Agricultural Biotechnology Research Center, Academia Sinica, Taipei 11529, Taiwan; Department of Aquaculture, National Taiwan Ocean University, Keelung 202, Taiwan; Institute of Pharmacology, Yang-Ming University, Taipei 112, Taiwan; Department of Life Sciences, National Chung-Hsing University, Taichung 402, Taiwan. 3. Department of Microbiology and Immunology, Institute of Microbiology and Immunology, Chung Shan Medical University, Taichung 402, Taiwan. 4. Department of Veterinary Medicine, National Chung Hsing University, Taichung 402, Taiwan. Electronic address: ltchang@nchu.edu.tw.
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE: Bidens pilosa, a tropical and sub-tropical herbal plant, is used as an ethnomedicine for bacterial infection or immune modulation in Asia, America and Africa. It has been demonstrated that cytopiloyne (CP), a bioactive polyacetylenic glucoside purified from B. pilosa, increases the percentage of macrophages in the spleen but the specific effects on macrophages remain unclear. AIM OF THE STUDY: The aim of this study was to evaluate the effects of CP on macrophage activity and host defense in BALB/c mice with Candida parapsilosis infection and investigate the likely mechanisms. MATERIALS AND METHODS: RAW264.7 cells, a mouse macrophage cell line, were used to assess the effects of CP on macrophage activity by phagocytosis assay, colony forming assay and acridine orange/crystal violet stain. To evaluate the activity of CP against C. parapsilosis, BALB/c mouse infection models were treated with/without CP and histopathological examination was performed. The role of macrophages in the infection model was clarified by treatment with carrageenan, a selective macrophage-toxic agent. RAW264.7 macrophage activities influenced by CP were further investigated by lysosome staining, phagosomal acidification assay, lysosome enzyme activity and PKC inhibitor GF109203X. RESULTS: The results showed that CP in vitro enhances the ability of RAW264.7 macrophages to engulf and clear C. parapsilosis. In the mouse model, CP treatment improved the survival rate of Candida-infected mice and lowered the severity of microscopic lesions in livers and spleens via a macrophage-dependent mechanism. Furthermore, with CP treatment, the fusion and acidification of phagolysosomes were accelerated and the lysosome enzyme activity of RAW264.7 macrophages was elevated. PKC inhibitor GF109203X reversed the increase in phagocytic activity by CP demonstrating that the PKC pathway is involved in the macrophage-mediated phagocytosis of C. parapsilosis. CONCLUSIONS: Our data suggested that CP, as an immunomodulator, enhances macrophage activity against C. parapsilosis infections.
ETHNOPHARMACOLOGICAL RELEVANCE: Bidens pilosa, a tropical and sub-tropical herbal plant, is used as an ethnomedicine for bacterial infection or immune modulation in Asia, America and Africa. It has been demonstrated that cytopiloyne (CP), a bioactive polyacetylenic glucoside purified from B. pilosa, increases the percentage of macrophages in the spleen but the specific effects on macrophages remain unclear. AIM OF THE STUDY: The aim of this study was to evaluate the effects of CP on macrophage activity and host defense in BALB/c mice with Candida parapsilosis infection and investigate the likely mechanisms. MATERIALS AND METHODS: RAW264.7 cells, a mouse macrophage cell line, were used to assess the effects of CP on macrophage activity by phagocytosis assay, colony forming assay and acridine orange/crystal violet stain. To evaluate the activity of CP against C. parapsilosis, BALB/c mouseinfection models were treated with/without CP and histopathological examination was performed. The role of macrophages in the infection model was clarified by treatment with carrageenan, a selective macrophage-toxic agent. RAW264.7 macrophage activities influenced by CP were further investigated by lysosome staining, phagosomal acidification assay, lysosome enzyme activity and PKC inhibitor GF109203X. RESULTS: The results showed that CP in vitro enhances the ability of RAW264.7 macrophages to engulf and clear C. parapsilosis. In the mouse model, CP treatment improved the survival rate of Candida-infectedmice and lowered the severity of microscopic lesions in livers and spleens via a macrophage-dependent mechanism. Furthermore, with CP treatment, the fusion and acidification of phagolysosomes were accelerated and the lysosome enzyme activity of RAW264.7 macrophages was elevated. PKC inhibitor GF109203X reversed the increase in phagocytic activity by CP demonstrating that the PKC pathway is involved in the macrophage-mediated phagocytosis of C. parapsilosis. CONCLUSIONS: Our data suggested that CP, as an immunomodulator, enhances macrophage activity against C. parapsilosis infections.