Saussureae Radix Attenuates Neuroinflammation in LPS-Stimulated Mouse BV2 Microglia via HO-1/Nrf-2 Induction and Inflammatory Pathway Inhibition

Physcion prevents induction of optic nerve injury in rats via inhibition of the JAK2/STAT3 pathway

Optic nerve injury is a type of neurodegenerative disease. Physcion is an anthraquinone that exerts a protective role against various diseases. However, its function in regulating optic nerve injury remains largely unknown. An in vitro model of optic nerve injury was established in HAPI cells treated with IFN-β. Functional assays were used to detect HAPI cell viability and apoptosis. The levels of inflammation and the expression levels of oxidative stress-related genes were measured in HAPI cells. In addition, western blot analysis was used to detect the expression levels of Janus kinase 2 (JAK2)/STAT3-linked genes in HAPI cells. Treatment of the cells with physcion prevented cells against IFN-β-induced neuronal injury. Physcion restrained IFN-β-induced inflammatory response and oxidative stress in HAPI cells. In addition, it improved IFN-β-induced injury in HAPI cells by suppressing the JAK2/STAT3 pathway. In conclusion, the present study revealed that physcion improved optic nerve injury in vitro by inhibiting the JAK2/STAT3 pathway. Physcion may be a promising therapeutic target for the treatment of this disease.

Costunolide alleviates hyperglycaemia-induced diabetic cardiomyopathy via inhibiting inflammatory responses and oxidative stress

Hyperglycaemia-induced myocardial injury promotes the induction of heart failure in diabetic patients. Impaired antioxidant capability and sustained chronic inflammation play a vital role in the progression of diabetic cardiomyopathy (DCM). Costunolide (Cos), a natural compound with anti-inflammatory and antioxidant properties, has exhibited therapeutic effects in various inflammatory diseases. However, the role of Cos in diabetes-induced myocardial injury remains poorly understood. In this study, we investigated the effect of Cos on DCM and explored the potential mechanisms. C57BL/6 mice were administered intraperitoneal streptozotocin for DCM induction. Cos-mediated anti-inflammatory and antioxidation activities were examined in heart tissues of diabetic mice and high glucose (HG)-stimulated cardiomyocytes. Cos markedly inhibited HG-induced fibrotic responses in diabetic mice and H9c2 cells, respectively. The cardioprotective effects of Cos could be correlated to the reduced expression of inflammatory cytokines and decreased oxidative stress. Further investigations demonstrated Cos reversed diabetes-induced nuclear factor-κB (NF-κB) activation and alleviated impaired antioxidant defence system, principally via activation of nuclear factor-erythroid 2 p45-related factor-2 (Nrf-2). Cos alleviated cardiac damage and improved cardiac function in diabetic mice by inhibiting NF-κB-mediated inflammatory responses and activating the Nrf-2-mediated antioxidant effects. Therefore, Cos could be a potential candidate for the treatment of DCM.

An active fraction from Spatholobus suberectus dunn inhibits the inflammatory response by regulating microglia activation, switching microglia polarization from M1 to M2 and suppressing the TLR4/MyD88/NF-κB pathway in LPS-stimulated BV2 cells

Neurodegenerative disorders are known to be associated with neuroinflammation caused by microglia. Therefore, regulation of microglia activation and polarization to inhibit neuroinflammatory reactions seems to hold promise as a therapeutic approach in neurodegenerative disorders. Spatholobus suberectus Dunn (SSD) has been utilized as a traditional Chinese medicine remedy for brain diseases for thousands of years. SSD possesses various pharmacological activities, such as circulation invigoration, neuroprotection, and anti-inflammatory. The objective of this research was to examine the anti-neuroinflammatory effects and molecular mechanisms of an active fraction from SSD (ASSD) in vitro culture BV2 cells, a type of mouse microglia cell line. The inflammatory responses in BV2 cells were induced by stimulating them with 1 μg/mL lipopolysaccharide (LPS) and the effects of ASSD on LPS-stimulated inflammation were monitored. Besides, by using the methods of Western blot, immunofluorescence, and RT-PCR, the mechanisms of ASSD on microglia activation, M1/M2 polarization, and the TLR4/MyD88/NF-κB pathway were investigated. Our findings demonstrate that the treatment doses of ASSD neither induce cytotoxicity nor promote the production of inflammatory cytokines. In addition, immunofluorescence analysis show that ASSD inhibited the expression of ionized calcium-binding adapter molecule 1(Iba1) and inducible nitricoxide synthase (iNOS), and induced arginase 1 (Arg1) expression. Moreover, Western blot analysis indicated that ASSD significantly down-regulated TLR4, MyD88, p-IκB, NF-κB p65, and NF-κB p-p65 protein expression levels. Furthermore, RT-qPCR assay show that ASSD significantly down-regulated iNOS, TLR4, MyD88, and NF-κB mRNA expression levels, and up-regulated Arg1 mRNA expression level. According to the findings, ASSD can suppress microglia-mediated inflammatory responses by modulating microglia activation, inducing a shift from M1 to M2 polarization, and inhibiting the TLR4/MyD88/NF-κB signaling pathway.

6-methoxyflavone suppresses neuroinflammation in lipopolysaccharide- stimulated microglia through the inhibition of TLR4/MyD88/p38 MAPK/NF-κB dependent pathways and the activation of HO-1/NQO-1 signaling

BACKGROUND

Microglia-related neuroinflammation is associated with a variety of neurodegenerative diseases. Flavonoids have demonstrated different pharmacological effects, such as antioxidation, neuroprotection and anti-inflammation However, the effect of flavonoid 6-methoxyflavone (6-MeOF) on microglia-mediated neuroinflammation remain unknown.

PURPOSE

The current study aim to study the antineuroinflammatory effects of 6-MeOF in lipopolysaccharide- (LPS-) induced microglia in vitro and in vivo.

METHODS

Pretreatment of BV2 microglia cells with 6-MeOF for 1 h then stimulated with LPS (100 ng/ml) for 24 h. The expression levels of pro-inflammatory factors, NO and reactive oxygen species (ROS) were performed by the enzyme-linked immunosorbent assay (ELISA), Griess assay and flow cytometry. Western blotting was used to assess MAPK, NF-κB signal transducer and antioxidant enzymes-related proteins. Analysis of ROS and microglial morphology was confirmed in the zebrafish and mice brain, respectively.

RESULTS

Our results demonstrated that 6-MeOF dose-dependently prevent cell death and decreased the levels of pro-inflammatory mediators in LPS-stimulated BV2 microglia cells. Phosphorylated NF-κB/IκB and TLR4/MyD88/p38 MAPK/JNK proteins after exposure to 6-MeOF was suppressed in LPS-activated BV-2 microglial cells. 6-MeOF also presented antioxidant activity by reduction of NO, ROS, iNOS and COX-2 and the induction of the level of HO-1 and NQO1 expressions in LPS-activated BV2 microglial cells. Furthermore, we demonstrated that 6-MeOF inhibited LPS-induced NO generation in an experimental zebrafish model and prevent the LPS-induced microgliosis in the prefrontal cortex and substantia nigra of mice.

CONCLUSION

These results explored that 6-MeOF possesses potential as anti-inflammatory and anti-oxidant agents against microglia-associated neuroinflammatory disorders.

Hispidin inhibits LPS-induced nitric oxide production in BV-2 microglial cells via ROS-dependent MAPK signaling

Neuroinflammation is associated with many neurodegenerative diseases. Abnormal activation of microglial cells in the central nervous system (CNS) is a major characteristic of neuroinflammation. Nitric oxide (NO) free radicals are produced by activated microglia and prolonged presence of large quantities of NO in the CNS can lead to neuroinflammation and disease. Hispidin is a polyphenol derived from Phellinus linteus (a valuable medicinal mushroom) with strong antioxidant, anticancer and antidiabetic properties. A previous study demonstrated that hispidin significantly inhibited NO production via lipopolysaccharide (LPS)-induced RAW264.7 macrophages. Therefore, the present study used MTT assay was used to detect the effect of hispdin on cell viability. Griess reagent analysis was used to measure NO production. Reverse transcription-semi quantitative PCR and western blotting were used to evaluate the effects of hispdin on iNOS mRNA and MAPK/ERK/JNK protein levels. Fluorescence microscopy and flow cytometry were used to detect the effects of hispdin on the production of ROS and phagocytosis of cells. The present results indicated that hispidin could significantly inhibit the increase of NO production and iNOS expression in BV-2 microglial cells stimulated by LPS. The inhibitory effect of hispidin on NO production was similar to that of S-methylisothiourea sulfate, an iNOS inhibitor. Signaling studies demonstrated that hispidin markedly suppresses LPS-induced mitogen activated protein kinases and JAK1/STAT3 activation, although not the NF-κB signaling pathway. The present observations in LPS-stimulated BV-2 microglial cells indicated that hispidin might serve as a therapeutic candidate for the treatment of NO-induced neuroinflammation and, potentially, as a novel iNOS inhibitor.