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Abstract：
BACKGROUND: Schistosoma japonicum eggs lodge in the liver and induce a fibrotic granulomatous immune response in the liver of host. Galectin 3 (Gal-3) is a protein implicated in fibrosis in multiple organs. However, the pathology and molecular mechanisms promoting hepatic granuloma formation remain poorly understood.
METHODS: To investigate the effect of blocking galectin-receptor interactions by α-lactose on liver immunopathology in mice with S. japonicum infection, C57BL/6 mice were infected with S. japonicum and alpha (α)-lactose was intraperitoneally injected to block the interactions of galectins and their receptors.
RESULTS: Compared with S. japonicum-infected mice, there were significantly decreased Gal-3 mRNA and protein expression levels, decreased intensity of Gal-3 fluorescence in the liver, decreased serum ALT and AST levels, decreased egg numbers of S. japonicum in the liver section, attenuated hepatic and spleen pathology, and alleviated liver fibrosis accompanied with decreased protein expression levels of fibrosis markers [α-smooth muscle actin (α-SMA), collagen I, and collagen IV] in the liver of S. japonicum-infected mice blocked galectin-receptor interactions with hematoxylin-eosin staining, Masson\'s trichrome staining, immunohistochemistry, or Western blot analysis. Compared with S. japonicum-infected mice, blocking galectin-receptor interactions led to increased eosinophil infiltration and higher eosinophil cationic protein (ECP) expression in the liver, accompanied by increased mRNA levels of eosinophil granule proteins [ECP and eosinophil peroxidase (EPO)], IL-5, CCL11, and CCR3 in the liver and decreased mRNA levels of Gal-3 and M2 macrophage cytokines (TGF-β, IL-10, and IL-4) in the liver and spleen by using quantitative real-time reverse transcription-polymerase chain reaction. In addition, there were increased Beclin1 protein expression and protein expression ratio of LC3B-II/LC3B-I and decreased p62 protein expression and protein expression ratios of phospho-mTOR/mTOR and phospho-AKT/AKT by Western blot; increased double-labeled F4/80+/LC3B+ cells by immunofluorescence staining; increased M1 macrophage polarization in the liver of S. japonicum-infected mice blocked galectin-receptor interactions by flow cytometric analysis and immunofluorescence staining.
CONCLUSIONS: Our data found that blockage of galectin-receptor interactions downregulated Gal-3, which in turn led to reduced liver functional damage, elevated liver eosinophil recruitment, promoted macrophage autophagy through the Akt/mTOR signaling pathway, and alleviated liver pathology and fibrosis. Therefore, Gal-3 plays a pivotal role during S. japonicum infection and could be a target of pharmacologic potential for liver fibrosis induced by S. japonicum infection.
METHODS: To investigate the effect of blocking galectin-receptor interactions by α-lactose on liver immunopathology in mice with S. japonicum infection, C57BL/6 mice were infected with S. japonicum and alpha (α)-lactose was intraperitoneally injected to block the interactions of galectins and their receptors.
RESULTS: Compared with S. japonicum-infected mice, there were significantly decreased Gal-3 mRNA and protein expression levels, decreased intensity of Gal-3 fluorescence in the liver, decreased serum ALT and AST levels, decreased egg numbers of S. japonicum in the liver section, attenuated hepatic and spleen pathology, and alleviated liver fibrosis accompanied with decreased protein expression levels of fibrosis markers [α-smooth muscle actin (α-SMA), collagen I, and collagen IV] in the liver of S. japonicum-infected mice blocked galectin-receptor interactions with hematoxylin-eosin staining, Masson\'s trichrome staining, immunohistochemistry, or Western blot analysis. Compared with S. japonicum-infected mice, blocking galectin-receptor interactions led to increased eosinophil infiltration and higher eosinophil cationic protein (ECP) expression in the liver, accompanied by increased mRNA levels of eosinophil granule proteins [ECP and eosinophil peroxidase (EPO)], IL-5, CCL11, and CCR3 in the liver and decreased mRNA levels of Gal-3 and M2 macrophage cytokines (TGF-β, IL-10, and IL-4) in the liver and spleen by using quantitative real-time reverse transcription-polymerase chain reaction. In addition, there were increased Beclin1 protein expression and protein expression ratio of LC3B-II/LC3B-I and decreased p62 protein expression and protein expression ratios of phospho-mTOR/mTOR and phospho-AKT/AKT by Western blot; increased double-labeled F4/80+/LC3B+ cells by immunofluorescence staining; increased M1 macrophage polarization in the liver of S. japonicum-infected mice blocked galectin-receptor interactions by flow cytometric analysis and immunofluorescence staining.
CONCLUSIONS: Our data found that blockage of galectin-receptor interactions downregulated Gal-3, which in turn led to reduced liver functional damage, elevated liver eosinophil recruitment, promoted macrophage autophagy through the Akt/mTOR signaling pathway, and alleviated liver pathology and fibrosis. Therefore, Gal-3 plays a pivotal role during S. japonicum infection and could be a target of pharmacologic potential for liver fibrosis induced by S. japonicum infection.
摘要：
背景：日本血吸虫卵滞留在肝脏中，并在宿主肝脏中诱导纤维化肉芽肿性免疫反应。半乳糖凝集素3(Gal-3)是涉及多个器官中的纤维化的蛋白质。然而,促进肝肉芽肿形成的病理和分子机制仍然知之甚少。
方法：为了研究α-乳糖阻断半乳糖凝集素受体相互作用对日本血吸虫感染小鼠肝脏免疫病理学的影响，用日本血吸虫感染C57BL/6小鼠，并腹膜内注射α（α）-乳糖以阻断半乳糖凝集素及其受体的相互作用。
结果：与日本血吸虫感染小鼠相比，Gal-3mRNA和蛋白表达水平显著降低，肝脏中Gal-3荧光强度降低，降低血清ALT和AST水平，肝脏切片中日本血吸虫的卵数减少，减弱的肝和脾病理，并减轻肝纤维化伴随纤维化标志物[α-平滑肌肌动蛋白（α-SMA）的蛋白表达水平降低，胶原蛋白I，和胶原蛋白IV]在日本血吸虫感染的小鼠的肝脏中，用苏木精-伊红染色阻断了半乳糖凝集素-受体相互作用，马森三色染色，免疫组织化学，或蛋白质印迹分析。与日本血吸虫感染小鼠相比，阻断半乳糖凝集素-受体相互作用导致肝脏中嗜酸性粒细胞浸润增加和嗜酸性粒细胞阳离子蛋白（ECP）表达增加，伴随着嗜酸性粒细胞颗粒蛋白[ECP和嗜酸性粒细胞过氧化物酶（EPO）]的mRNA水平增加，肝脏中的IL-5，CCL11和CCR3以及Gal-3和M2巨噬细胞细胞因子的mRNA水平降低（TGF-β，通过使用定量实时逆转录聚合酶链反应，肝脏和脾脏中的IL-10和IL-4）。此外,通过Westernblot，LC3B-II/LC3B-I的Beclin1蛋白表达和蛋白表达比率增加，磷酸化mTOR/mTOR和磷酸化AKT/AKT的p62蛋白表达和蛋白表达比率降低；通过免疫荧光染色，双标记的F4/80/LC3B细胞增加；S.感染小鼠肝脏中的巨噬细胞极化增加。
结论：我们的数据发现阻断半乳糖凝集素受体相互作用下调Gal-3，这反过来导致肝功能损害减少，肝脏嗜酸性粒细胞募集升高，通过Akt/mTOR信号通路促进巨噬细胞自噬，减轻肝脏病理和纤维化。因此,Gal-3在日本血吸虫感染期间起着关键作用，并且可能是日本血吸虫感染诱导的肝纤维化的药理潜力的靶标。
方法：为了研究α-乳糖阻断半乳糖凝集素受体相互作用对日本血吸虫感染小鼠肝脏免疫病理学的影响，用日本血吸虫感染C57BL/6小鼠，并腹膜内注射α（α）-乳糖以阻断半乳糖凝集素及其受体的相互作用。
结果：与日本血吸虫感染小鼠相比，Gal-3mRNA和蛋白表达水平显著降低，肝脏中Gal-3荧光强度降低，降低血清ALT和AST水平，肝脏切片中日本血吸虫的卵数减少，减弱的肝和脾病理，并减轻肝纤维化伴随纤维化标志物[α-平滑肌肌动蛋白（α-SMA）的蛋白表达水平降低，胶原蛋白I，和胶原蛋白IV]在日本血吸虫感染的小鼠的肝脏中，用苏木精-伊红染色阻断了半乳糖凝集素-受体相互作用，马森三色染色，免疫组织化学，或蛋白质印迹分析。与日本血吸虫感染小鼠相比，阻断半乳糖凝集素-受体相互作用导致肝脏中嗜酸性粒细胞浸润增加和嗜酸性粒细胞阳离子蛋白（ECP）表达增加，伴随着嗜酸性粒细胞颗粒蛋白[ECP和嗜酸性粒细胞过氧化物酶（EPO）]的mRNA水平增加，肝脏中的IL-5，CCL11和CCR3以及Gal-3和M2巨噬细胞细胞因子的mRNA水平降低（TGF-β，通过使用定量实时逆转录聚合酶链反应，肝脏和脾脏中的IL-10和IL-4）。此外,通过Westernblot，LC3B-II/LC3B-I的Beclin1蛋白表达和蛋白表达比率增加，磷酸化mTOR/mTOR和磷酸化AKT/AKT的p62蛋白表达和蛋白表达比率降低；通过免疫荧光染色，双标记的F4/80/LC3B细胞增加；S.感染小鼠肝脏中的巨噬细胞极化增加。
结论：我们的数据发现阻断半乳糖凝集素受体相互作用下调Gal-3，这反过来导致肝功能损害减少，肝脏嗜酸性粒细胞募集升高，通过Akt/mTOR信号通路促进巨噬细胞自噬，减轻肝脏病理和纤维化。因此,Gal-3在日本血吸虫感染期间起着关键作用，并且可能是日本血吸虫感染诱导的肝纤维化的药理潜力的靶标。
