Fangle Liu1, Yufeng Yao2, Zenghui Lu2, Qiuyu Zhang2, Changhui Liu2, Chenchen Zhu3, Chaozhan Lin4. 1. School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, PR China; School of Basic Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, PR China. 2. School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, PR China. 3. School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, PR China. Electronic address: zhucc@gzucm.edu.cn. 4. School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, PR China. Electronic address: linchaozhan@gzucm.edu.cn.
Abstract
BACKGROUND: 5-Hydroxy-4-methoxycanthin-6-one (PQ-A) is the main active compound in Ramulus et Folium Picrasmae, a Chinese herbal medicine commonly used in colitis treatment. PURPOSE: To clarify PQ-A's role and mechanism in colitis treatment based on a non-targeted metabolomics study. METHODS: Rats with ulcerative colitis (UC) established with 4% dextran sulfate sodium (DSS) were orally treated with PQ-A. Body weight, disease activity index (DAI), colon length, biochemical parameters (MDA and SOD), and histopathological score in colon tissue were measured. A UPLC-Q-TOF-MS/MS approach-based metabolomics analysis was conducted to explore the underlying mechanisms of PQ-A in colitis treatment. Inflammatory cytokines (TNF-α, IL-1β, IL-6, and IL-10) concentrations in serum and their protein levels in the colon were determined. CD3 and NF-κB/p65 immunohistochemistry in the colon was semi-quantified. The related protein or mRNA in IKK-NF-κB/p65 signaling pathway was measured by Western blotting or RT-PCR, respectively. Potential molecular interactions between PQ-A and NF-κB/p65 was predicted using DS 2.5 software. RESULTS: PQ-A significantly prevented body weight loss and colonic shortening in colitic rats, and reduced the DAI and histopathologic score as well. PQ-A decreased MDA levels in the UC rat serum and increased those of SOD. Metabolomics results revealed forty-nine differential metabolites as biomarkers of DSS-induced colitis, demonstrating that the path-mechanism of colitis involved the perturbation of eight metabolic pathways, including alpha-linolenic acid and linoleic acid metabolism, sphingolipid metabolism, retinol metabolism, bile acid metabolism, et al. Thirty-six biomarkers were especially reversed to normal-like levels by PQ-A via regulation of alpha-linolenic acid and linoleic acid metabolism, sphingolipid metabolism, and retinol metabolism, which effectively hinted the potential pharmacological mechanism of PQ-A related to NF-κB/p65 inflammatory signaling. Molecular docking results predicted high affinity interaction between PQ-A and NF-κB/p65, involving hydrogen-bond interactions at five amino acid residues, suggesting NF-κB/p65 as a target. PQ-A decreased TNF-α, IL-1β, and IL-6 concentrations in serum and their protein levels in colon tissue in colitic rats. CD3, MYD88, p-IκBα, NF-κB/p65, and p-NF-κB/p65 expression levels decreased, whereas those of IKKβ and IκBα increased in colitic tissue following PQ-A treatment. PQ-A strongly inhibited nuclear translocation of NF-κB/p65. CONCLUSIONS: We provide an overview of PQ-A's possible mechanism of action in colitis treatment based on serum non-targeted metabolomics. PQ-A treatment can protect rats against DSS-induced colitis by suppressing the NF-κB/p65 signaling pathway.
BACKGROUND:5-Hydroxy-4-methoxycanthin-6-one (PQ-A) is the main active compound in Ramulus et Folium Picrasmae, a Chinese herbal medicine commonly used in colitis treatment. PURPOSE: To clarify PQ-A's role and mechanism in colitis treatment based on a non-targeted metabolomics study. METHODS:Rats with ulcerative colitis (UC) established with 4% dextran sulfate sodium (DSS) were orally treated with PQ-A. Body weight, disease activity index (DAI), colon length, biochemical parameters (MDA and SOD), and histopathological score in colon tissue were measured. A UPLC-Q-TOF-MS/MS approach-based metabolomics analysis was conducted to explore the underlying mechanisms of PQ-A in colitis treatment. Inflammatory cytokines (TNF-α, IL-1β, IL-6, and IL-10) concentrations in serum and their protein levels in the colon were determined. CD3 and NF-κB/p65 immunohistochemistry in the colon was semi-quantified. The related protein or mRNA in IKK-NF-κB/p65 signaling pathway was measured by Western blotting or RT-PCR, respectively. Potential molecular interactions between PQ-A and NF-κB/p65 was predicted using DS 2.5 software. RESULTS:PQ-A significantly prevented body weight loss and colonic shortening in colitic rats, and reduced the DAI and histopathologic score as well. PQ-A decreased MDA levels in the UC rat serum and increased those of SOD. Metabolomics results revealed forty-nine differential metabolites as biomarkers of DSS-induced colitis, demonstrating that the path-mechanism of colitis involved the perturbation of eight metabolic pathways, including alpha-linolenic acid and linoleic acid metabolism, sphingolipid metabolism, retinol metabolism, bile acid metabolism, et al. Thirty-six biomarkers were especially reversed to normal-like levels by PQ-A via regulation of alpha-linolenic acid and linoleic acid metabolism, sphingolipid metabolism, and retinol metabolism, which effectively hinted the potential pharmacological mechanism of PQ-A related to NF-κB/p65 inflammatory signaling. Molecular docking results predicted high affinity interaction between PQ-A and NF-κB/p65, involving hydrogen-bond interactions at five amino acid residues, suggesting NF-κB/p65 as a target. PQ-A decreased TNF-α, IL-1β, and IL-6 concentrations in serum and their protein levels in colon tissue in colitic rats. CD3, MYD88, p-IκBα, NF-κB/p65, and p-NF-κB/p65 expression levels decreased, whereas those of IKKβ and IκBα increased in colitic tissue following PQ-A treatment. PQ-A strongly inhibited nuclear translocation of NF-κB/p65. CONCLUSIONS: We provide an overview of PQ-A's possible mechanism of action in colitis treatment based on serum non-targeted metabolomics. PQ-A treatment can protect rats against DSS-induced colitis by suppressing the NF-κB/p65 signaling pathway.