The saponin ginsenoside Rk1 is a major compound isolated from ginseng. Ginsenoside Rk1 has been reported to have anti-inflammatory and anti-tumor properties and to be involved in the regulation of metabolism. However, the effect and mechanism of anti-inflammatory action of ginsenoside Rk1 has not been fully clarified. We investigated whether ginsenoside Rk1 could suppress the inflammatory response in lipopolysaccharide-stimulated RAW264.7 macrophages and to explore its mechanism of the action. RAW264.7 cells were treated with LPS (1 μg·mL) in the absence or the presence of Ginsenoside Rk1 (10, 20, and 40 μmol·L). Then the inflammatory factors were tested with Griess reagents, ELISA, and RT-PCR. The proteins were analyzed by Western blotting. Ginsenoside Rk1 inhibited lipopolysaccharide-induced expression of nitric oxide (NO), interleukin (IL)-6, IL-1β, tumor necrosis factor (TNF)-α, and monocyte chemotactic protein (MCP)-1. Ginsenoside Rk1 inhibited the lipopolysaccharide-stimulated phosphorylation of NF-κB and janus kinase (Jak)2 and signal transducer and activator of transcription (Stat)3 at Ser727 and Tyr705. These data suggested that ginsenoside Rk1 could inhibit expression of inflammatory mediators and suppress inflammation further by blocking activation of NF-κB and the Jak2/Stat3 pathway in LPS-stimulated RAW264.7 cells.
Animals ; Anti-Inflammatory Agents ; pharmacology ; Ginsenosides ; pharmacology ; Interleukin-6 ; genetics ; immunology ; Janus Kinase 2 ; genetics ; immunology ; Lipopolysaccharides ; pharmacology ; Macrophages ; drug effects ; immunology ; Mice ; RAW 264.7 Cells ; STAT3 Transcription Factor ; genetics ; immunology ; Tumor Necrosis Factor-alpha ; genetics ; immunology

BACKGROUNDAutoantibodies against angiotensin AT1 receptor have been discovered in patients with preeclampsia or malignant hypertension. Some studies have demonstrated that the autoantibodies are involved in the immunopathogenesis of hypertension and have an agonist effect similar to angiotensin II.

METHODSAutoantibodies against AT1 receptor were purified from sera of patients with primary hypertension by affinity chromatography. Proliferation of cultured rat vascular smooth muscle cells was detected by bromodeoxyuridine incorporation and activation of signalling molecules detected by Western blotting and electrophoretic mobility shift assay.

RESULTSThe AT1-RAb caused a significant proliferation similar to the Ang II during first 24 hours. The levels of nuclear factor-kappaB (NF-kappaB), phosphorylated JAK2, phosphorylated STAT1 (pSTAT1) and phosphorylated STAT3 (pSTAT3) molecules were increased in response to the autoantibodies. In contrast, the activations of NF-kappaB and JAK-STAT were blocked by losartan, pyrrolidinedithiocarbamate (a specific inhibitor of NF-kappaB) and AG490 (a specific inhibitor of the JAK2 tyrosine kinase). The expressions of NF-kappaB, pSTAT1 and pSTAT3 reached peak levels at different times. Moreover, the relative densities of electrophoretic bands showed that activation of pSTAT3 was more significant than STAT1 induced by AT1-RAb.

CONCLUSIONSThese results suggest that the autoantibodies against AT1 receptor have an agonist effect similar to Ang II in proliferation of VSMCs and the NF-kappaB and JAK-STAT proteins play essential roles. The effect is different from Ang II in that STAT3 is the main downstream activating molecule in JAK-STAT signalling pathway.

Animals ; Autoantibodies ; immunology ; Cell Proliferation ; Humans ; Hypertension ; immunology ; Janus Kinase 2 ; physiology ; Muscle, Smooth, Vascular ; cytology ; NF-kappa B ; physiology ; Rats ; Rats, Wistar ; Receptor, Angiotensin, Type 1 ; immunology ; STAT3 Transcription Factor ; physiology ; Signal Transduction ; physiology

To study the preventive effect of sophocarpine (Soc) on dextran sulfate sodium (DSS)-induced colitis in mice, in order to analyze the influence of Soc on toll like receptor 4 (TLR4)/mitogen-activated protein kinases (MAPKs) and janus tyrosine kinase 2 signal transducer and activator of transcription 3 (JAK2/STAT3) signal pathways in mice intestinal tissues. The mice was given 2.5% DSS for 6 days to induce the acute colitis model. The Soc-treated group was intraperitoneally injected with sophocarpine 30 mg · kg(-1) · d(-1) since the day before the experiment to the end. The disease activity index (DAI) was assessed everyday, and the colonic morphology and histological damage were observed with HE staining. The mRNA expressions of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) were detected by real-time RT-PCR. The changes in key protein kinase p38 mitogen-activated protein kinase (p38MAPK), c-Jun NH2-terminal protein kinase1/2 (JNK1/2), extracellular signal-regulated kinase1/2 (ERK1/2), JAK2, STAT3 in TLR4/MAPKs and JAK2/STAT3 signaling pathways were detected by western blot. The result showed that the model group showed statistical significance in body weight, DAI, colon length and histopathological changes compared with the normal group (P <0.05); however, the Soc-treated group showed significant improvements in the above indexes compared with the model group (P <0.05). TNF-α, IL-1β and IL-6 in the model group was significantly higher than that in the normal group (P <0.05), but lowered in the Soc-treated group to varying degrees (P <0.05). In the normal group, the expressions of TLR4 and the phosphorylation of P38, JNK1/2, JAK2, STAT3 were at low levels; in the model group, the phosphorylation of P38, JNK1/2, JAK2, STAT3 increased; the Soc-treated group showed a decrease in TLR4 expression compared with the model group, with notable declines in the phosphorylation of TLR4, P38, JNK1/2, JAK2, STAT3. These findings indicate that Soc can inhibit TLR4/MAPKs, K2/STAT3 signaling pathway activation, reduce the expression of proinflammatory cytokines TNF-α, IL-1β and IL-6 and relieve inflammatory reactions, so as to effectively prevent experimental colitis.
Alkaloids ; pharmacology ; therapeutic use ; Animals ; Colitis ; drug therapy ; immunology ; pathology ; Cytokines ; genetics ; Janus Kinase 2 ; antagonists & inhibitors ; physiology ; Male ; Mice ; Mice, Inbred BALB C ; Phosphorylation ; STAT3 Transcription Factor ; antagonists & inhibitors ; physiology ; Toll-Like Receptor 4 ; antagonists & inhibitors ; physiology

OBJECTIVE: This study aimed to investigate the effects of caprylic acid (C8:0) on lipid metabolism and inflammation, and examine the mechanisms underlying these effects in mice and cells. METHODS: Fifty-six 6-week-old male C57BL/6J mice were randomly allocated to four groups fed a high-fat diet (HFD) without or with 2% C8:0, palmitic acid (C16:0) or eicosapentaenoic acid (EPA). RAW246.7 cells were randomly divided into five groups: normal, lipopolysaccharide (LPS), LPS+C8:0, LPS+EPA and LPS+cAMP. The serum lipid profiles, inflammatory biomolecules, and ABCA1 and JAK2/STAT3 mRNA and protein expression were measured. RESULTS: C8:0 decreased TC and LDL-C, and increased the HDL-C/LDL-C ratio after injection of LPS. Without LPS, it decreased TC in mice ( P < 0.05). Moreover, C8:0 decreased the inflammatory response after LPS treatment in both mice and cells ( P < 0.05). Mechanistic investigations in C57BL/6J mouse aortas after injection of LPS indicated that C8:0 resulted in higher ABCA1 and JAK2/STAT3 expression than that with HFD, C16:0 and EPA, and resulted in lower TNF-α, NF-κB mRNA expression than that with HFD ( P < 0.05). In RAW 264.7 cells, C8:0 resulted in lower expression of pNF-κBP65 than that in the LPS group, and higher protein expression of ABCA1, p-JAK2 and p-STAT3 than that in the LPS and LPS+cAMP groups ( P < 0.05). CONCLUSION Our studies demonstrated that C8:0 may play an important role in lipid metabolism and the inflammatory response, and the mechanism may be associated with ABCA1 and the p-JAK2/p-STAT3 signaling pathway.
ATP Binding Cassette Transporter 1/immunology* ; Animals ; Caprylates/chemistry* ; Cholesterol/metabolism* ; Diet, High-Fat/adverse effects* ; Humans ; Inflammation/metabolism* ; Janus Kinase 2/immunology* ; Lipid Metabolism/drug effects* ; Macrophages/immunology* ; Male ; Mice ; Mice, Inbred C57BL ; RAW 264.7 Cells ; STAT3 Transcription Factor/immunology* ; Signal Transduction

Macrophages show significant heterogeneity in function and phenotype, which could shift into different populations of cells in response to exposure to various micro-environmental signals. These changes, also termed as macrophage polarization, of which play an important role in the pathogenesis of many diseases. Numerous studies have proved that Hesperidin (HDN), a traditional Chinese medicine, extracted from fruit peels of the genus citrus, play key roles in anti-inflammation, anti-tumor, anti-oxidant and so on. However, the role of HDN in macrophage polarization has never been reported. Additional, because of its poor water solubility and bioavailability. Our laboratory had synthesized many hesperidin derivatives. Among them, hesperidin derivatives-12 (HDND-12) has better water solubility and bioavailability. So, we evaluated the role of HDND-12 in macrophage polarization in the present study. The results showed that the expression of Arginase-1 (Arg-1), interleukin-10 (IL-10), transforming growth factor β (TGF-β) were up-regulated by HDND-12, whereas the expression of inducible Nitric Oxide Synthase (iNOS) was down-regulated in LPS- and IFN-γ-treated (M1) RAW264.7 cells. Moreover, the expression of p-JAK2 and p-STAT3 were significantly decreased after stimulation with HDND-12 in M1-like macrophages. More importantly, when we taken AG490 (inhibitor of JAK2/STAT3 signaling), the protein levels of iNOS were significantly reduced in AG490 stimulation group compare with control in LPS, IFN-γ and HDND-12 stimulation cells. Taken together, these findings indicated that HDND-12 could prevent polarization toward M1-like macrophages, at least in part, through modulating JAK2/STAT3 pathway.
Animals ; Cytokines ; genetics ; metabolism ; Enzyme Inhibitors ; pharmacology ; Gene Expression Regulation ; drug effects ; Hesperidin ; chemistry ; pharmacology ; Inflammation ; genetics ; metabolism ; Janus Kinase 2 ; antagonists & inhibitors ; metabolism ; Macrophages ; drug effects ; immunology ; metabolism ; Medicine, Chinese Traditional ; Mice ; Molecular Structure ; Phosphorylation ; drug effects ; RAW 264.7 Cells ; STAT3 Transcription Factor ; antagonists & inhibitors ; metabolism ; Signal Transduction ; drug effects