Anemoside B4, a new pyruvate carboxylase inhibitor, alleviates colitis by reprogramming macrophage function.

OBJECTIVES: Colitis is a global disease usually accompanied by intestinal epithelial damage and intestinal inflammation, and an increasing number of studies have found natural products to be highly effective in treating colitis. Anemoside B4 (AB4), an abundant saponin isolated from Pulsatilla chinensis (Bunge), which was found to have strong anti-inflammatory activity. However, the exact molecular mechanisms and direct targets of AB4 in the treatment of colitis remain to be discovered. METHODS: The anti-inflammatory activities of AB4 were verified in LPS-induced cell models and 2, 4, 6-trinitrobenzene sulfonic (TNBS) or dextran sulfate sodium (DSS)-induced colitis mice and rat models. The molecular target of AB4 was identified by affinity chromatography analysis using chemical probes derived from AB4. Experiments including proteomics, molecular docking, biotin pull-down, surface plasmon resonance (SPR), and cellular thermal shift assay (CETSA) were used to confirm the binding of AB4 to its molecular target. Overexpression of pyruvate carboxylase (PC) and PC agonist were used to study the effects of PC on the anti-inflammatory and metabolic regulation of AB4 in vitro and in vivo. RESULTS: AB4 not only significantly inhibited LPS-induced NF-κB activation and increased ROS levels in THP-1 cells, but also suppressed TNBS/DSS-induced colonic inflammation in mice and rats. The molecular target of AB4 was identified as PC, a key enzyme related to fatty acid, amino acid and tricarboxylic acid (TCA) cycle. We next demonstrated that AB4 specifically bound to the His879 site of PC and altered the protein's spatial conformation, thereby affecting the enzymatic activity of PC. LPS activated NF-κB pathway and increased PC activity, which caused metabolic reprogramming, while AB4 reversed this phenomenon by inhibiting the PC activity. In vivo studies showed that diisopropylamine dichloroacetate (DADA), a PC agonist, eliminated the therapeutic effects of AB4 by changing the metabolic rearrangement of intestinal tissues in colitis mice. CONCLUSION: We identified PC as a direct cellular target of AB4 in the modulation of inflammation, especially colitis. Moreover, PC/pyruvate metabolism/NF-κB is crucial for LPS-driven inflammation and oxidative stress. These findings shed more light on the possibilities of PC as a potential new target for treating colitis.

Suitability evaluation on material specifications and edible methods of Dendrobii Officinalis Caulis based on holistic polysaccharide marker.

BACKGROUND: Dendrobii Officinalis Caulis (DC) is a well-known tonic herbal medicine worldwide and has favorable immunomodulatory activity. Various material specifications of DC are available in herbal markets, and DC is ingested by different edible methods. However, whether these specifications and edible methods are suitable or not remains unknown. METHODS: In this study, we evaluated the suitability of four material specifications (fresh stem, dried stem, fengdou and powder) and three edible methods (making tea, soup and medicinal liquor) based on holistic polysaccharide marker (HPM), the major polysaccharide components in DC. First, the HPMs were extracted from the four specifications of DC by the three edible methods in different conditions. Second, qualitative and quantitative characterization of the extracted HPMs was performed using high performance gel permeation chromatography (HPGPC). Third, immunomodulatory activities of the extracted HPMs were evaluated in vivo. RESULTS: The results showed that the HPMs were found to be quantitatively different from various specification of DC and edible methods. In vivo analysis indicated that the HPMs exerted positive effects on innate immune responses by increment in proliferation of splenocytes, secretion of IL-2 and cytotoxicity activity of NK cells. Moreover, the dosage amount of HPM should be defined as a certain range, but not the larger the better, for exerting strong immunological activities. CONCLUSION: According to the both chemical and biological results, fengdou by boiling with water for 4 h is the most recommended specification and edible method for DC.

Antioxidant activity of phenylethanoid glycosides on glutamate-induced neurotoxicity.

Exposure of PC12 cells to 10 mM glutamate caused significant viability loss, cell apoptosis, decreased activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) as well as increased levels of malondialdehyde (MDA). In parallel, glutamate significantly increased the intracellular levels of ROS and intracellular calcium. However, pretreatment of the cells with acteoside and isoacteoside significantly suppressed glutamate-induced cellular events. Moreover, acteoside and isoacteoside reduced the glutamate-induced increase of caspase-3 activity and also ameliorated the glutamate-induced Bcl-2/Bax ratio reduction in PC12 cells. Furthermore, acteoside and isoacteoside significantly inhibited glutamate-induced DNA damage. In the mouse model, acteoside significantly attenuated cognitive deficits in the Y maze test and attenuated neuronal damage of the hippocampal CA1 regions induced by glutamate. These data indicated that acteoside and isoacteoside play neuroprotective effects through anti-oxidative stress, anti-apoptosis, and maintenance of steady intracellular calcium.