Discovery and verification of anti-inflammatory-related quality markers in the aerial part of Bupleurum scorzonerifolium by UPLC-Q-TOF-MS/MS and in RAW 264.7 cells and a zebrafish model.

INTRODUCTION: The root of Bupleurum scorzonerifolium Willd. (BS) is officially recognized in the Chinese Pharmacopoeia. In contrast, the aerial part of BS (ABS), accounting for 80% of BS, is typically discarded, causing potential waste of medicinal resources. ABS has shown benefits in the treatment of inflammation-related diseases in China and Spain, and the material basis underlying its anti-inflammatory effects must be systematically elucidated for the rational use of ABS. OBJECTIVE: We aimed to screen and validate the anti-inflammatory quality markers (Q-markers) of ABS and to confirm the ideal time for ABS harvesting. METHODS: The chemical components and anti-inflammatory effects of ABS from 10 extracted parts were analyzed by UPLC-Q-TOF-MS/MS and in a lipopolysaccharide (LPS)-induced cell model. Anti-inflammatory substances were screened by Pearson bivariate analysis and gray correlation analysis, and the anti-inflammatory effects were verified in a zebrafish tail-cutting inflammation model. HPLC was applied to measure the Q-marker contents of ABS in different harvesting periods. RESULTS: Ten ABS extracts effectively alleviated the increase in LPS-induced proinflammatory cytokines in RAW 264.7 cells. Forty components were identified from them, among which 27 were common components. Eight components were correlated with anti-inflammatory effects, which were confirmed to reverse the expression of proinflammatory and anti-inflammatory factors in a zebrafish model. Chlorogenic acid, hypericin, rutin, quercetin, and isorhamnetin can be detected by HPLC, and the maximum contents of these five Q-markers were obtained in the sample harvested in August. CONCLUSION: The anti-inflammatory Q-markers of ABS were elucidated by chromatographic-pharmacodynamic-stoichiometric analysis, which served as a crucial basis for ABS quality control.

GLP-2 Attenuates LPS-Induced Inflammation in BV-2 Cells by Inhibiting ERK1/2, JNK1/2 and NF-κB Signaling Pathways.

The pathogenesis of Parkinson's disease (PD) often involves the over-activation of microglia. Over-activated microglia could produce several inflammatory mediators, which trigger excessive inflammation and ultimately cause dopaminergic neuron damage. Anti-inflammatory effects of glucagon-like peptide-2 (GLP-2) in the periphery have been shown. Nonetheless, it has not been illustrated in the brain. Thus, in this study, we aimed to understand the role of GLP-2 in microglia activation and to elucidate the underlying mechanisms. BV-2 cells were pretreated with GLP-2 and then stimulated by lipopolysaccharide (LPS). Cells were assessed for the responses of pro-inflammatory enzymes (iNOS and COX-2) and pro-inflammatory cytokines (IL-1ß, IL-6 and TNF-α); the related signaling pathways were evaluated by Western blotting. The rescue effect of GLP-2 on microglia-mediated neurotoxicity was also examined. The results showed that GLP-2 significantly reduced LPS-induced production of inducible nitric oxide synthase (iNOS), cyclooxygenase-s (COX-2), IL-1ß, IL-6 and TNF-α. Blocking of Gαs by NF449 resulted in a loss of this anti-inflammatory effect in BV-2 cells. Analyses in signaling pathways demonstrated that GLP-2 reduced LPS-induced phosphorylation of ERK1/2, JNK1/2 and p65, while no effect was observed on p38 phosphorylation. In addition, GLP-2 could suppress microglia-mediated neurotoxicity. All results imply that GLP-2 inhibits LPS-induced microglia activation by collectively regulating ERK1/2, JNK1/2 and p65.

Anti-inflammatory effects of BHBA in both in vivo and in vitro Parkinson's disease models are mediated by GPR109A-dependent mechanisms.

BACKGROUND: Accumulating evidence suggests that neuroinflammation plays an important role in the progression of Parkinson's disease (PD). Excessively activated microglia produce several pro-inflammatory enzymes and pro-inflammatory cytokines, leading to damage to surrounding neurons and eventually inducing neurodegeneration. Therefore, the inhibition of microglial overactivation may be a potential therapeutic strategy to prevent the further progression of PD. ß-Hydroxybutyric acid (BHBA) has been shown to suppress lipopolysaccharide (LPS)-induced inflammation in BV-2 cells and to protect dopaminergic neurons in previous studies, but the underlying mechanisms remain unclear. Thus, in this study, we further investigated this mechanism in LPS-induced in vivo and in vitro PD models. METHODS: For the in vitro experiments, primary mesencephalic neuron-glia cultures were pretreated with BHBA and stimulated with LPS. [(3)H]dopamine (DA) uptake, tyrosine hydroxylase-immunoreactive (TH-ir) neurons and morphological analysis were evaluated and analyzed in primary mesencephalic neuron-glia cultures. In vivo, microglial activation and the injury of dopaminergic neurons were induced by LPS intranigral injection, and the effects of BHBA treatment on microglial activation and the survival ratio and function of dopaminergic neurons were investigated. Four our in vitro mechanistic experiment, primary microglial cells were pretreated with BHBA and stimulated with LPS; the cells were then assessed for the responses of pro-inflammatory enzymes and pro-inflammatory cytokines, and the NF-κB signaling pathway was evaluated and analyzed. RESULTS: We found that BHBA concentration-dependently attenuated the LPS-induced decrease in [(3)H]DA uptake and loss of TH-ir neurons in the primary mesencephalic neuron/glia mixed culture. BHBA treatment significantly improved the motor dysfunction of the PD model rats induced by intranigral injection of LPS, and this beneficial effect of BHBA was attributed to the inhibition of microglial overactivation and the protection of dopaminergic neurons in the substantia nigra (SN). Our in vitro mechanistic study revealed that the inhibitory effect of BHBA on microglia was mediated by G-protein-coupled receptor 109A (GPR109A) and involved the NF-κB signaling pathway, causing the inhibition of pro-inflammatory enzyme (iNOS and COX-2) and pro-inflammatory cytokine (TNF-α, IL-1ß, and IL-6) production. CONCLUSIONS: In conclusion, the present study supports the effectiveness of BHBA in protecting dopaminergic neurons against inflammatory challenge.

Mycophenolate Mofetil Modulates Differentiation of Th1/Th2 and the Secretion of Cytokines in an Active Crohn's Disease Mouse Model.

Mycophenolate mofetil (MMF) is an alternative immunosuppressive agent that has been reported to be effective and well tolerated for the treatment of refractory inflammatory bowel disease (IBD). The aim of this study was to investigate the therapeutic effect of MMF on intestinal injury and tissue inflammation, which were caused by Crohn's disease (CD). Here, trinitrobenzene sulfonic acid-relapsing (TNBS) colitis was induced in mice; then, we measured the differentiation of Th1/Th2 cells in mouse splenocytes by flow cytometry and the secretion of cytokines in mice with TNBS-induced colitis by real-time polymerase chain reaction and/or enzyme-linked immunosorbent assay (RT-PCR/ELISA). The results show that MMF significantly inhibited mRNA expression of pro-inflammatory cytokines IFN-γ, TNF-α, IL-12, IL-6, and IL-1ß in mice with TNBS-induced colitis; however, MMF did not inhibit the expression of IL-10 mRNA. Additionally, ELISA showed that the serum levels of IFN-γ, TNF-α, IL-12, IL-6, and IL-1ß were down-regulated in a TNBS model of colitis. Flow cytometric analysis showed MMF markedly reduced the percentages of Th1 and Th2 splenocytes in the CD mouse model. Mycophenolic acid (MPA) also significantly decreased the percentages of splenic Th1 and Th2 cells in vitro. Furthermore, MMF treatment not only significantly ameliorated diarrhea, and loss of body weight but also abrogated the histopathologic severity and inflammatory response of inflammatory colitis, and increased the survival rate of TNBS-induced colitic mice. These results suggest that treatment with MMF may improve experimental colitis and induce inflammatory response remission of CD by down-regulation of pro-inflammatory cytokines via modulation of the differentiation of Th1/Th2 cells.

BHBA suppresses LPS-induced inflammation in BV-2 cells by inhibiting NF-κB activation.

ß-Hydroxybutyric acid (BHBA) has neuroprotective effects, but the underlying molecular mechanisms are unclear. Microglial activation plays an important role in neurodegenerative diseases by producing several proinflammatory enzymes and proinflammatory cytokines. The current study investigates the potential mechanisms whereby BHBA affects the expression of potentially proinflammatory proteins by cultured murine microglial BV-2 cells stimulated with lipopolysaccharide (LPS). The results showed that BHBA significantly reduced LPS-induced protein and mRNA expression levels of iNOS, COX-2, TNF-α, IL-1ß, and IL-6. Blocking of GPR109A by PTX resulted in a loss of this anti-inflammatory effect in BV-2 cells. Western blot analysis showed that BHBA reduced LPS-induced degradation of IκB-α and translocation of NF-κB, while no effect was observed on MAPKs phosphorylation. All results imply that BHBA significantly reduces levels of proinflammatory enzymes and proinflammatory cytokines by inhibition of the NF-κB signaling pathway but not MAPKs pathways, and GPR109A is essential to this function. Overall, these data suggest that BHBA has a potential as neuroprotective drug candidate in neurodegenerative diseases.

IL-21 modulates release of proinflammatory cytokines in LPS-stimulated macrophages through distinct signaling pathways.

The aim of this study was to investigate the anti-inflammatory effect of IL-21 on LPS-induced mouse peritoneal macrophages. The results showed that IL-21 significantly inhibited LPS-induced mRNA expression of IL-1ß, TNF-α, and IL-6 in macrophages, but not of IFN-γ, IL-10, CCL5, or CXCL2. ELISA analysis showed that IL-21 also suppressed LPS-induced production of TNF-α and IL-6 in culture supernatants. Western blot analysis showed that IL-21 clearly inhibited ERK and IκBα phosphorylation and NF-κB translocation in LPS-stimulated macrophages, but it increased STAT3 phosphorylation. Flow cytometric and Western blot analysis showed that IL-21 decreased M1 macrophages surface markers expression of CD86, iNOS, and TLR4 in LPS-stimulated cells. All results suggested that IL-21 decreases IL-6 and TNF-α production via inhibiting the phosphorylation of ERK and translocation of NF-κB and promotes a shift from the M1 to M2 macrophage phenotype by decreasing the expression of CD86, iNOS, and TLR4 and by increasing STAT3 phosphorylation in LPS-stimulated cells.

Short-chain fatty acids inhibit growth hormone and prolactin gene transcription via cAMP/PKA/CREB signaling pathway in dairy cow anterior pituitary cells.

Short-chain fatty acids (SCFAs) play a key role in altering carbohydrate and lipid metabolism, influence endocrine pancreas activity, and as a precursor of ruminant milk fat. However, the effect and detailed mechanisms by which SCFAs mediate bovine growth hormone (GH) and prolactin (PRL) gene transcription remain unclear. In this study, we detected the effects of SCFAs (acetate, propionate, and butyrate) on the activity of the cAMP/PKA/CREB signaling pathway, GH, PRL, and Pit-1 gene transcription in dairy cow anterior pituitary cells (DCAPCs). The results showed that SCFAs decreased intracellular cAMP levels and a subsequent reduction in PKA activity. Inhibition of PKA activity decreased CREB phosphorylation, thereby inhibiting GH and PRL gene transcription. Furthermore, PTX blocked SCFAs- inhibited cAMP/PKA/CREB signaling pathway. These data showed that the inhibition of GH and PRL gene transcription induced by SCFAs is mediated by Gi activation and that propionate is more potent than acetate and butyrate in inhibiting GH and PRL gene transcription. In conclusion, this study identifies a biochemical mechanism for the regulation of SCFAs on bovine GH and PRL gene transcription in DCAPCs, which may serve as one of the factors that regulate pituitary function in accordance with dietary intake.

Establishment and characterization of dairy cow growth hormone secreting anterior pituitary cell model.

A dairy cow anterior pituitary cell (DCAPC) model was established in vitro for the study of growth hormone (GH) synthesis and secretion in the anterior pituitary gland of the dairy cow. Pituitary glands were obtained from Holstein dairy cows' heads cut by electric saw, and the posterior pituitary glands were removed to obtain integrated anterior pituitary glands. Immunohistochemistry assay of GH in the anterior pituitary glands showed that most somatotrophs were located within the lateral wings of the anterior pituitary. Tissues of the lateral wings of the anterior pituitary were dispersed and cultured in Dulbecco's modified Eagle's medium supplemented with 10% fetal bovine serum. The DCAPCs displayed a monolayer, cobblestone, epithelial-like morphology which are the typical characteristics of the anterior pituitary cells. The DCAPCs were subcultured continuously over ten passages. GH immunoreactivity was present in DCAPCs at passage 10. The transcription of the bovine GH mRNA in DCAPCs at passage 10 was decreased to below 50% compared with the lateral wings of the anterior pituitary tissues. Thus, our DCAPCs model is effective for the in vitro examination of GH synthesis and secretion in the dairy cow anterior pituitary gland. The effects of transforming growth factor beta 1 (TGF-ß1) and interferon-γ (IFN-γ) on the expression of GH mRNA in DCAPCs at passage 3 were also investigated. There were no obvious changes in transcription of the GH gene after treatment with TGF-ß1 for 24 h, while IFN-γ increased transcription of the GH gene in a dose-dependent manner.