RESUMO
Akebia saponin D (ASD) is derived from the Dipsacus asper Wall. ex Henry, which is a traditional Chinese medicine commonly used to treat rheumatic arthritis (RA). However, the in-depth mechanism of the anti-inflammatory effect of ASD is still unclear. This study aimed to preliminarily explore the anti-inflammatory effect of ASD and the underlying mechanisms from the perspective of DNA methylation and inflammation-related pathways. We found that ASD significantly reduced the production of multiple inflammatory mediators, including nitric oxide (NO) and prostaglandin E2 (PGE2), in LPS-induced RAW264.7 cells. The expression of DNA methyltransferase (DNMT) 3b and inducible nitric oxide synthase (iNOS) was also obviously inhibited by the ASD treatment. The protein and mRNA levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were also significantly inhibited by ASD. ASD inhibited the macrophage M1 phenotype, inhibited the high level of DNMT3b, and downregulated the signal transducer and activator of the transcription 3 (STAT3) pathway to exert its anti-inflammatory activity. Furthermore, DNMT3b siRNA and Nrf2 siRNA significantly promoted the anti-inflammatory effect of ASD. Our study demonstrates for the first time that ASD inhibits the IL-6-STAT3-DNMT3b axis and activates the nuclear factor-E2-related factor 2 (Nrf2) signaling pathway to achieve its inhibitory effect on inflammatory reactions.
Assuntos
Interleucina-6 , Fator 2 Relacionado a NF-E2 , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/uso terapêutico , DNA/uso terapêutico , Dinoprostona/metabolismo , Humanos , Inflamação/induzido quimicamente , Inflamação/tratamento farmacológico , Inflamação/metabolismo , Mediadores da Inflamação/metabolismo , Interleucina-6/genética , Interleucina-6/metabolismo , Lipopolissacarídeos/farmacologia , Metiltransferases/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , NF-kappa B/metabolismo , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase Tipo II/genética , Óxido Nítrico Sintase Tipo II/metabolismo , RNA Mensageiro , RNA Interferente Pequeno/uso terapêutico , Fator de Transcrição STAT3 , Saponinas , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismoRESUMO
The side effects of nonsteroidal anti-inflammatory drugs (NSAIDs) in the cardiovascular system mainly result from its inhibitory effect on cyclooxygenase-2 (COX-2). Since NSAIDs are one of the most commonly used anti-inflammatory drugs in the clinic, it is necessary to identify new anti-inflammatory drugs that are safer than NSAIDs. Nardosinanone N (NAN), a compound isolated from the roots and rhizomes of Nardostachys chinensis, was evaluated for its anti-inflammatory effects using the lipopolysaccharide (LPS)-stimulated RAW264.7 cell line and rat peritoneal macrophage models. First, we found that NAN down regulated the levels of nitric oxide (NO), inducible nitric oxide synthase (iNOS) and prostaglandin E2 (PGE2), but not cyclooxygenase-2 (COX-2). Additionally, NAN reduced the M1 macrophage phenotype and increased the M2 macrophage phenotype. Furthermore, mechanistic studies showed that NAN activated the nuclear factor-erythroid 2 -related factor 2 (Nrf2) signaling pathway, which, in turn, increased the expression of antioxidant protein heme oxygenase-1 (HO-1) to achieve its anti-inflammatory effect. Finally, Nrf2 siRNA and the HO-1 inhibitor significantly attenuated the anti-inflammatory effect of NAN. More interestingly, we found that NAN did not affect COX-2 expression and activity but reduced the PGE2 concentration by selective inhibition of microsomal prostaglandin E synthase-1 (mPGES-1). In conclusion, NAN may be a new anti-inflammatory drug that has fewer side effects than NSAIDs and can be a new potential Nrf2 activator and mPGES-1 inhibitor.
Assuntos
Compostos de Epóxi/farmacologia , Lipopolissacarídeos/farmacologia , Ativação de Macrófagos/efeitos dos fármacos , Fator 2 Relacionado a NF-E2/metabolismo , Nardostachys/química , Preparações de Plantas/farmacologia , Prostaglandina-E Sintases/metabolismo , Terpenos/farmacologia , Animais , Anti-Inflamatórios/química , Anti-Inflamatórios/farmacologia , Células Cultivadas , Ciclo-Oxigenase 2/genética , Ciclo-Oxigenase 2/metabolismo , Dinoprostona/metabolismo , Compostos de Epóxi/química , Expressão Gênica/efeitos dos fármacos , Macrófagos/classificação , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Camundongos , Microssomos/efeitos dos fármacos , Microssomos/enzimologia , Estrutura Molecular , Fator 2 Relacionado a NF-E2/genética , Óxido Nítrico Sintase Tipo II/genética , Óxido Nítrico Sintase Tipo II/metabolismo , Preparações de Plantas/química , Prostaglandina-E Sintases/genética , Células RAW 264.7 , Ratos , Transdução de Sinais/efeitos dos fármacos , Terpenos/química , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Nardochinoid B (NAB) is a new compound isolated from Nardostachys chinensis. Although our previous study reported that the NAB suppressed the production of nitric oxide (NO) in lipopolysaccharide (LPS)-activated RAW264.7 cells, the specific mechanisms of anti-inflammatory action of NAB remains unknown. Thus, we examined the effects of NAB against LPS-induced inflammation. In this study, we found that NAB suppressed the LPS-induced inflammatory responses by restraining the expression of inducible nitric oxide synthase (iNOS) proteins and mRNA instead of cyclooxygenase-2 (COX-2) protein and mRNA in RAW264.7 cells, implying that NAB may have lower side effects compared with nonsteroidal anti-inflammatory drugs (NSAIDs). Besides, NAB upregulated the protein and mRNA expressions of heme oxygenase (HO)-1 when it exerted its anti-inflammatory effects. Also, NAB restrained the production of NO by increasing HO-1 expression in LPS-stimulated RAW264.7 cells. Thus, it is considered that the anti-inflammatory effect of NAB is associated with an induction of antioxidant protein HO-1, and thus NAB may be a potential HO-1 inducer for treating inflammatory diseases. Moreover, our study found that the inhibitory effect of NAB on NO is similar to that of the positive drug dexamethasone, suggesting that NAB has great potential for developing new drugs in treating inflammatory diseases.