Lancemaside A inhibits microglial activation via modulation of JNK signaling pathway

The role of oxidative stress in aortic dissection: a potential therapeutic target

The incidence of aortic dissection (AD) is steadily increasing, driven by the rising prevalence of chronic conditions such as hypertension and the global aging of the population. Oxidative stress emerges as a pivotal pathophysiological mechanism contributing to the progression of AD. Oxidative stress triggers apoptosis in vascular smooth muscle cells, reshapes the extracellular matrix (ECM), and governs ECM degradation and remodeling, subsequently impacting aortic compliance. Furthermore, oxidative stress not only facilitates the infiltration of macrophages and mononuclear lymphocytes but also disrupts the integral structure and functionality of endothelial cells, thereby inducing endothelial cell dysfunction and furthering the degeneration of the middle layer of the aortic wall. Investigating antioxidants holds promise as a therapeutic avenue for addressing AD.

Lancemaside A from Codonopsis lanceolata prevents hypertension by inhibiting NADPH oxidase 2-mediated MAPK signalling and improving NO bioavailability in rats

OBJECTIVES

This study investigated whether lancemaside A (LMA) can prevent hypertension and assessed the mechanisms of action of LMA in rats.

METHODS

Hypertension was induced by chronic immobilization stress and nicotine administration. Hypertensive vehicle rats were treated with LMA (1, 20, or 40 mg/kg) or nifedipine (10 mg/kg) as a positive control daily for 3 weeks.

KEY FINDINGS

In hypertensive vehicle rats, LMA dose-dependently reduced systolic blood pressure. LMA doses of 20 and 40 mg/kg reduced the aortic expression of nicotinamide adenine dinucleotide phosphate oxidase (NOX)2 (both P < 0.01), and 40 mg/kg LMA reduced serum malondialdehyde (P < 0.01). Serum nitrite levels were significantly higher in LMA treated rats than in hypertensive vehicle rats, with LMA doses of 20 and 40 mg/kg reducing the expression of endothelial nitric oxide synthase in rat aortas (P < 0.001 and P < 0.01, respectively). LMA also reduced the aortic levels of nuclear factor kappa B and the activation of the three isoforms of mitogen-activated protein kinase (MAPK).

CONCLUSIONS

Lancemaside A prevents hypertension in rats by inhibiting the activation of MAPK signalling and the impairment in nitric oxide bioavailability due to NOX2-mediated oxidative stress. Thus, LMA may act as a preventive agent for hypertension.

Lancemaside A, a major triterpene saponin of Codonopsis lanceolata enhances regulation of nitric oxide synthesis via eNOS activation

Background

Many studies on the effect of saponin-rich Codonopsis lanceolata as a bioactive source for improving physical health have been performed. C. lanceolata contains triterpenoid saponins, including lancemasides. These saponins are known to be particularly involved in the regulation of blood pressure or hypertension. This study investigated whether lancemaside A (LA), a major triterpenoid saponin from C. lanceolata, regulates nitric oxide (NO) production via the activation of endothelial NO synthase (eNOS) in human umbilical vein endothelial cells.

Methods

Upon separation with petroleum ether, ethyl acetate, and n-butanol, LA was found to be abundant in the n-butanol-soluble portion. For further purification of LA, HPLC was performed to collect fraction, and LA was identified using analysis of LC/MSMS and ¹³C-NMR values. In in vitro, the effects of LA on NO release mechanism in HUVECs were investigated by Griess assay, quantitative real-time reverse-transcription PCR, and Western blotting.

Results

Our results showed that NO production was efficiently improved by treatment with LA in a dose-dependent manner. In addition, the LA treatment resulted in extensive recovery of the NO production suppressed by the eNOS inhibitor, L-NAME, compared with that in the control group. Additionally, the level of eNOS mRNA was increased by this treatment in a dose-dependent manner. These results suggested that LA is an inducer of NO synthesis via eNOS mRNA expression. Also, the study indicated that LA is involved in activating the PI3K/Akt/eNOS signaling pathway.

Conclusion

These results suggested that LA is an inducer of NO synthesis via eNOS mRNA expression. Also, the study indicated that LA is involved in activating the PI3K/Akt/eNOS signaling pathway. These findings suggest the value of using LA as a component of functional foods and natural pharmaceuticals.

Electronic supplementary material

The online version of this article (10.1186/s12906-019-2516-6) contains supplementary material, which is available to authorized users.

Codonopsis lanceolata Water Extract Increases Hepatic Insulin Sensitivity in Rats with Experimentally-Induced Type 2 Diabetes

We examined the mechanisms and efficacy of Codonopsis lanceolata water extract (CLW) for treating type 2 diabetic (T2DM) symptoms. Partial pancreatectomized (Px) rats, a non-obese T2DM model, were provided high fat diets containing cellulose (control), 0.3% (CLW-L) or 1% CLW (CLW-H) for eight weeks. The positive control group was provided with rosiglitazone (20 mg/kg bw/day). The control group had lower epididymal fat masses than the CLW and the positive control groups, possibly due to urinary glucose loss, although CPT-1 and SIRT-1 expression was higher in the CLW group. CLW-H significantly reduced serum glucose levels and urinary glucose loss compared to the untreated control. The improvement of glucose utilization was associated with a higher fat mass in the CLW-H and positive control groups. Glucose-stimulated insulin secretion was higher in the untreated control than other groups and CLW tightly regulated insulin secretion as much as the positive control, and it was much tighter than the untreated control. Glucose infusion rates were higher during the hyperinsulinemic euglycemic clamp in the CLW and positive controls than the untreated control, and liver glucose outputs were lower during basal and hyperinsulinemic conditions in the CLW and positive control groups than the untreated control group. The increased hepatic insulin sensitivity was associated with enhanced insulin signaling in CLW (pAkt➔pGSK-1β). In conclusion, CLW consumption effectively alleviated diabetic symptoms by improving insulin sensitivity, potentiating hepatic insulin signaling and tightly regulating the insulin secretion capacity in non-obese T2DM rats.

Anti-inflammatory effects of glaucocalyxin B in microglia cells

Over-activated microglia is involved in various kinds of neurodegenerative process including Parkinson, Alzheimer and HIV dementia. Suppression of microglial over activation has emerged as a novel strategy for treatment of neuroinflammation-based neurodegeneration. In the current study, anti-inflammatory and neuroprotective effects of the ent-kauranoid diterpenoids, which were isolated from the aerial parts of Rabdosia japonica (Burm. f.) var. glaucocalyx (Maxim.) Hara, were investigated in cultured microglia cells. Glaucocalyxin B (GLB), one of five ent-kauranoid diterpenoids, significantly decreased the generation of nitric oxide (NO), tumor necrosis factor (TNF)-α, interleukin (IL)-1β, cyclooxygenase (COX)-2 and inducible nitric oxide synthase (iNOS) in the lipopolysaccharide (LPS)-activated microglia cells. In addition, GLB inhibited activation of nuclear factor-κB (NF-κB), p38 mitogen-activated protein kinase (MAPK) and generation of reactive oxygen species (ROS) in LPS-activated microglia cells. Furthermore, GLB strongly induced the expression of heme oxygenase (HO)-1 in BV-2 microglia cells. Finally, GLB exhibited neuroprotective effect by preventing over-activated microglia induced neurotoxicity in a microglia/neuron co-culture model. Taken together, the present study demonstrated that the GLB possesses anti-nueroinflammatory activity, and might serve as a potential therapeutic agent for treating neuroinflammatory diseases.

Synthesis and biological evaluation of substituted N-[3-(1H-pyrrol-1-yl)methyl]-1,2,5,6-tetrahydropyridin-1-yl]benzamide/benzene sulfonamides as anti-inflammatory agents

The pharmacological activities of tetrahydropyridine (THP) derivatives are dependent on the substituent ring moiety. In this study, we investigate the anti-inflammatory activities of 12 newly synthesized substituted N-[3-(1H-pyrrol-1-yl)methyl]-1,2,5,6-tetrahydrobenzamide/benzene sulfonamides (9a-l) in murine BV-2 microglial cells. All compounds were initially screened for attenuation of nitric oxide (NO) production in lipopolysaccharide (LPS) (1 µg/mL)-activated microglial cells. The data show that only SO2 -substituted THPs were effective at sub-lethal concentrations (IC50 values of 12.92 µM (9i), 14.64 µM (9j), 19.63 µM (9k)) relative to L-N6-(1-iminoethyl)lysine positive control (IC50  = 3.1 µM). The most potent SO2 -substituted compound (9i) also blocked the LPS-inducible nitric oxide synthase (iNOS) and attenuated the release of several cytokines including IL-1α, IL-10, and IL-6. These findings establish the moderate immuno-modulating effects of SO2 -substituted THP derivatives.

Lancemaside A from Codonopsis lanceolata modulates the inflammatory responses mediated by monocytes and macrophages

In this study, we aimed to examine the cellular and molecular mechanisms of lancemaside A from Codonopsis lanceolata (Campanulaceae) in the inflammatory responses of monocytes (U937 cells) and macrophages (RAW264.7 cells). Lancemaside A significantly suppressed the inflammatory functions of lipopolysaccharide- (LPS-) treated RAW264.7 cells by suppressing the production of nitric oxide (NO), the expression of the NO-producing enzyme inducible NO synthase (iNOS), the upregulation of the costimulatory molecule CD80, and the morphological changes induced by LPS exposure. In addition, lancemaside A diminished the phagocytic activity of RAW264.7 cells and boosted the neutralizing capacity of these cells when treated with the radical generator sodium nitroprusside (SNP). Interestingly, lancemaside A strongly blocked the adhesion activity of RAW264.7 cells to plastic culture plates, inhibited the cell-cell and cell-fibronectin (FN) adhesion of U937 cells that was triggered by treatment with an anti-β1-integrin (CD29) antibody and immobilized FN, respectively. By evaluating the activation of various intracellular signaling pathways and the levels of related nuclear transcription factors, lancemaside A was found to block the activation of inhibitor of κB kinase (IKK) and p65/nuclear factor- (NF-) κB. Taken together, our findings strongly suggest that the anti-inflammatory function of lancemaside A is the result of its strong antioxidative and IKK/NF-κB inhibitory activities.

Kalopanaxsaponin A Exerts Anti-Inflammatory Effects in Lipopolysaccharide-Stimulated Microglia via Inhibition of JNK and NF-κB/AP-1 Pathways

Microglial activation plays an important role in the development and progression of various neurological disorders such as cerebral ischemia, multiple sclerosis, and Alzheimer's disease. Thus, controlling microglial activation can serve as a promising therapeutic strategy for such brain diseases. In the present study, we showed that kalopanaxsaponin A, a triterpenoid saponin isolated from Kalopanax pictus, inhibited inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and tumor necrosis factor (TNF)-α expression in lipopolysaccharide (LPS)-stimulated microglia, while kalopanaxsaponin A increased anti-inflammatory cytokine interleukin (IL)-10 expression. Subsequent mechanistic studies revealed that kalopanaxsaponin A inhibited LPS-induced DNA binding activities of NF-κB and AP-1, and the phosphorylation of JNK without affecting other MAP kinases. Furthermore, kalopanaxsaponin A inhibited the intracellular ROS production with upregulation of anti-inflammatory hemeoxygenase-1 (HO-1) expression. Based on the previous reports that JNK pathway is largely involved in iNOS and proinflammatory cytokine gene expression via modulating NF-κB/AP-1 and ROS, our data collectively suggest that inhibition of JNK pathway plays a key role in anti-inflammatory effects of kalopanaxsaponin A in LPS-stimulated microglia.