Department of Veterinary Medicine, National Chung Hsing University, Taichung 402, Taiwan.
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.
J Ethnopharmacol. 2016 May 26;184:72-80. doi: 10.1016/j.jep.2016.02.036. Epub 2016 Feb 26.
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.
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.
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.
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.
Our data suggested that CP, as an immunomodulator, enhances macrophage activity against C. parapsilosis infections.
三叶鬼针草，一种热带和亚热带草本植物，在亚洲、美洲和非洲被用作治疗细菌感染或免疫调节的民族药物。已证明，从三叶鬼针草中纯化的生物活性聚乙炔葡糖苷 Cytopiloyne（CP）可增加脾脏中巨噬细胞的百分比，但对巨噬细胞的具体作用尚不清楚。
本研究旨在评估 CP 对白色念珠菌感染 BALB/c 小鼠巨噬细胞活性和宿主防御的影响，并探讨可能的机制。
使用 RAW264.7 细胞，一种小鼠巨噬细胞系，通过吞噬试验、集落形成试验和吖啶橙/结晶紫染色来评估 CP 对巨噬细胞活性的影响。为了评估 CP 对白色念珠菌的活性，用 CP 处理 BALB/c 小鼠感染模型并进行组织病理学检查。用角叉菜胶（一种选择性巨噬细胞毒性药物）处理以阐明巨噬细胞在感染模型中的作用。通过溶酶体染色、吞噬体酸化测定、溶酶体酶活性和 PKC 抑制剂 GF109203X 进一步研究 CP 对 RAW264.7 巨噬细胞活性的影响。
结果表明，CP 在体外增强了 RAW264.7 巨噬细胞吞噬和清除白色念珠菌的能力。在小鼠模型中，CP 治疗通过巨噬细胞依赖性机制提高了白色念珠菌感染小鼠的存活率，并降低了肝脏和脾脏中微观病变的严重程度。此外，用 CP 治疗可加速吞噬溶酶体的融合和酸化，并提高 RAW264.7 巨噬细胞的溶酶体酶活性。PKC 抑制剂 GF109203X 逆转了 CP 引起的吞噬活性增加，表明 PKC 途径参与了 CP 介导的白色念珠菌吞噬作用。
我们的数据表明，CP 作为一种免疫调节剂，可增强巨噬细胞对白色念珠菌感染的活性。
