Anti-inflammatory effect of a novel synthetic compound 1-((4-fluorophenyl)thio)isoquinoline in RAW264.7 macrophages and a zebrafish model

Protective effect of N-(E)-p-coumaroyltyrosine on LPS-induced acute inflammatory injury and signaling pathway analysis

N-trans-p-coumaroyltyrosine (N-(E)-p-coumaroyltyrosine, NPCT), extracted and purified from Abri Mollis Herba, is an amino acid amide. The defense mechanism of NPCT against inflammatory response is still unknown. In this study, lipopolysaccharide (LPS)-induced zebrafish acute inflammatory injury model was established to observe the inhibitory effect of NPCT on the aggregation of inflammatory cells in the yolk sac of zebrafish, as well as the inhibitory effect of NPCT on inflammatory and gas signaling factors. Results show that NPCT could inhibit inflammatory cell infiltration in zebrafish yolk sac, the migration and aggregation of macrophages and neutrophils to the site of inflammation, and the release of Nitric Oxide (NO) and Reactive Oxygen Species (ROS) in zebrafish, indicating that NPCT could substantially significantly prevent the development of LPS-induced acute systemic inflammation. In addition, the analysis results of RNA-seq showed that in the model group versus the administered group, the differentially expressed genes were mainly enriched to inflammatory signaling pathways, such as the NOD-like receptor signaling pathway and Toll-like receptor signaling pathway, which were down-regulated in the administered group. The TLR4, MyD88, IRAK4, NF-κB, IκB, NLRP3, Caspase-1, ASC, IL-1β, and IL-6 genes were significantly different in the transcripts, and the overall trend of the qPCR results was consistent with the transcriptome sequencing results. Therefore, NPCT had a significant inhibitory effect on LPS-induced acute inflammatory injury in zebrafish, and its anti-inflammatory mechanism may be through the regulation of key genes on the NOD-like receptor signaling pathway and Toll-like receptor signaling pathway, thereby affecting the release of relevant inflammatory cytokines.

Anti-inflammatory effects of 6S-5-methyltetrahydrofolate‑calcium on RAW264.7 cells and zebrafish

AIM

6S-5-methyltetrahydrofolate is the predominant form of dietary folate in circulation and is used as a crystalline form of calcium salt (MTHF-Ca). Reports revealed that MTHF-Ca was more safe than folic acid, a synthetic and highly stable version of folate. Folic acid has been reported to have anti-inflammatory effects. The study's objective was to assess the anti-inflammatory effect of MTHF-Ca in vitro and in vivo.

MAIN METHODS

In vitro, the ROS production was assessed by H2DCFDA, and nuclear translocation of NF-κB were evaluated by the NF-κB nuclear translocation assay kit. Interleukin-6 (IL-6), interleukin-1β (IL-1β), and tumor necrosis factor-alpha (TNF-α) were assessed using ELISA. In vivo, ROS production was assessed by H2DCFDA, neutrophils and macrophages recruitment were evaluated in tail transection-induced and CuSO₄-induced zebrafish inflammation models. Expression of inflammation related genes were also investigated based on CuSO₄-induced zebrafish inflammation model.

KEY FINDINGS

MTHF-Ca treatment decreased LPS-induced ROS production, inhibited nuclear translocation of NF-κB and decreased the levels of IL-6, IL-1β and TNF-α in RAW264.7 cells. In addition, MTHF-Ca treatment inhibited ROS production, suppressed the recruitment of neutrophils and macrophages, and reduced the expression of inflammation related genes, including jnk, erk, nf-κb, myd88, p65, tnf-α, and il-1b in zebrafish larvae.

SIGNIFICANCE

MTHF-Ca may play an anti-inflammatory role by reducing the recruitment of neutrophils and macrophages and keeping the low levels of proinflammatory mediators and cytokines. MTHF-Ca may have a potential role in the treatment of inflammatory diseases.

Abrusamide H Impairs the Secretion of the Cytokines in RAW264.7 Cells and the Inflammatory Infiltration in Tail Transection-Induced Zebrafish

Abrus mollis Hance (Leguminosae) has a variety of biological activities, including anti-inflammatory, antioxidant, antibacterial, antiviral, and antitumor activities. However, the specific substances responsible for the anti-inflammatory effects are unknown. Abrusamide H (BJBS) is a truxillic acid derivative obtained from the leaves of Abrus mollis Hance and has potential anti-inflammatory effects. In this study, we aimed to estimate the potential effect and mechanism of BJBS in inflammation by establishing lipopolysaccharide (LPS)-stimulated RAW264.7 cells in vitro and an injured zebrafish tail fin in vivo. The RAW264.7 cells were treated with different concentrations of BJBS after LPS stimulation. The production of nitric oxide (NO) was detected by Griess reaction, and reactive oxygen species (ROS) were detected by an ROS assay kit. The levels of proinflammatory cytokines, including interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), and interleukin 18 (IL-18) were measured by ELISA. Results showed that BJBS at all concentrations inhibited the proliferation of RAW264.7 macrophages after LPS stimulation by cell counting kit-8 and the production of NO and ROS. In the BJBS treatment group, the levels of IL-6, TNF-α, IL-1β, and IL-18 decreased in a concentration-dependent manner. The results in vivo showed that no significant difference in the survival of zebrafish between the BJBS and blank groups and BJBS inhibited the migration and aggregation of zebrafish neutrophils in a dose-dependent manner in inflammation induced by tail transection-induced inflammation. In conclusion, BJBS inhibited the production of NO and ROS, decreased the levels of secreted IL-6, TNF-α, IL-1β, and IL-18, and reduced the migration and aggregation of zebrafish neutrophils.

Transgenic zebrafish larvae as a non-rodent alternative model to assess pro-inflammatory (neutrophil) responses to nanomaterials

Hazard studies for nanomaterials (NMs) commonly assess whether they activate an inflammatory response. Such assessments often rely on rodents, but alternative models are needed to support the implementation of the 3Rs principles. Zebrafish (Danio rerio) offer a viable alternative for screening NM toxicity by investigating inflammatory responses. Here, we used non-protected life stages of transgenic zebrafish (Tg(mpx:GFP)ⁱ¹¹⁴) with fluorescently-labeled neutrophils to assess inflammatory responses to silver (Ag) and zinc oxide (ZnO) NMs using two approaches. Zebrafish were exposed to NMs via water following a tail fin injury, or NMs were microinjected into the otic vesicle. Zebrafish were exposed to NMs at 3 days post-fertilization (dpf) and neutrophil accumulation at the injury or injection site was quantified at 0, 4, 6, 8, 24, and 48 h post-exposure. Zebrafish larvae were also exposed to fMLF, LTB₄, CXCL-8, C5a, and LPS to identify a suitable positive control for inflammation induction. Aqueous exposure to Ag and ZnO NMs stimulated an enhanced and sustained neutrophilic inflammatory response in injured zebrafish larvae, with a greater response observed for Ag NMs. Following microinjection, Ag NMs stimulated a time-dependent neutrophil accumulation in the otic vesicle which peaked at 48 h. LTB₄ was identified as a positive control for studies investigating inflammatory responses in injured zebrafish following aqueous exposure, and CXCL-8 for microinjection studies that assess responses in the otic vesicle. Our findings support the use of transgenic zebrafish to rapidly screen the pro-inflammatory effects of NMs, with potential for wider application in assessing chemical safety (e.g. pharmaceuticals).

Screening of Bufadienolides from Toad Venom Identifies Gammabufotalin as a Potential Anti-inflammatory Agent

Toad venom (Chansu) is used in the treatment of infectious and inflammatory diseases in China and East/Southeast Asian countries. However, the anti-inflammatory components of toad venom have not yet been systematically evaluated and clearly defined. To investigate the anti-inflammatory effects of toad venom and identify new anti-inflammatory ingredients, we used zebrafish, an alternative drug screening model, to evaluate the anti-inflammatory effects of 14 bufadienolides previously isolated from toad venom. Most of the bufadienolides were found to exert significant anti-inflammatory effects on lipopolysaccharide-, CuSO₄-, or tail transection-induced zebrafish inflammatory models. Moreover, gammabufotalin ( 6: ) inhibits lipopolysaccharide-induced inflammation by suppressing the myeloid differentiation primary response 88/nuclear factor-kappa B and STAT3 signal pathways. This study confirms the potential of zebrafish in drug screening, clarifies the anti-inflammatory effects of bufadienolides from toad venom, and indicates that gammabufotalin may be developed as a novel therapeutic agent for inflammatory diseases in the future.

Effect of Emodin on Hyperlipidemia and Hepatic Lipid Metabolism in Zebrafish Larvae Fed a High-Cholesterol Diet

Hyperlipidemia (HLP) is a complex pathological condition results from lipid metabolism disorder, which is closely related to obesity, atherosclerosis and steatohepatitis. Emodin (EM), a natural anthraquinone, exhibits prominent hypolipidemic effects. However, its exact mechanism is still unclear. In this study, we successfully established hyperlipidemic zebrafish model induced by 4 % high-cholesterol diet (HCD) for 10 days and explored the anti-hyperlipidemic roles and underlying mechanisms of EM. The results indicated that EM attenuated the mortality and body mass index (BMI) of zebrafish with HLP, and ameliorated abnormal lipid levels involved in TC, TG, LDL-C and HDL-C levels. Besides, EM effectively reduced lipid accumulation in blood vessels and liver, alleviated hepatic histological damage, and inhibited vascular neutrophil inflammation. Finally, the mRNA expression of molecules related to lipid metabolism were studied by using real-time quantitative polymerase chain reaction (RT-qPCR) to investigated the underlying mechanism. Further results found that treatment with EM up-regulated AMPKα, LDLR, ABCA1 and ABCG1, and down-regulated SREBP-2, PCSK9 and HMGCR expression. In conclusion, EM showed a prominent mitigative effect on lipid metabolism disorder in zebrafish larvae with HCD-stimulated HLP, which was associated with the enhancement of LDL-C uptake and reverse cholesterol transport, and inhibition of cholesterol synthesis.

Down-regulation of complement genes in lipopolysaccharide-challenged zebrafish (Danio rerio) larvae exposed to Indonesian propolis

Although propolis has been reported for having anti-inflammatory activities, its effects on complement system has not been much studied. This research was conducted to find out the effects of Indonesian propolis on the expression levels of C3, C1r/s, Bf, MBL, and C6 in zebrafish larvae which were induced by lipopolysaccharide (LPS). Counting of macrophages migrating to yolk sac and liver histology were carried out. Larvae were divided into four groups: CON (cultured in E3 medium only), LPS (cultured in a medium containing 0.5 μg/L LPS), LPSIBU (cultured in a medium containing LPS, and then treated with 100 μg/L ibuprofen for 24 hours), and LPSPRO (cultured in a medium containing LPS, and then immersed in 14,000 μg/L propolis for 24 hours) groups. The results showed that complement gene expression in larvae from the LPSIBU and LPSPRO groups were generally lower than in larvae from the LPS group. The number of macrophage migrations to the yolk in the LPSPRO group was also lower than in the LPS group. Histological structure of liver in all groups were considered normal. This study shows that Indonesian propolis has the potential to be used as an alternative to the substitution of NSAIDs.

Sheng-Mai Yin exerts anti-inflammatory effects on RAW 264.7 cells and zebrafish

ETHNOPHARMACOLOGICAL RELEVANCE

Sheng-Mai Yin (SMY), a famous traditional Chinese medicine formula, has been commonly used in China for centuries to treat various diseases, such as inflammation-related diseases. However, the anti-inflammatory activity of SMY and its potential mechanisms still have not yet been clearly understood.

AIM OF THE STUDY

In this study, we aimed to determine the anti-inflammatory effect of SMY and explore its underlying mechanisms both on RAW 264.7 cells and zebrafish.

MATERIALS AND METHODS

The levels of pro-inflammatory cytokines IL-6 and TNF-α secreted by RAW 264.7 cells were measured by ELISA. The protein expressions of IκBα, p-IκBα (Ser32), STAT3 and p-STAT3 (Tyr705) were determined by Western blotting. And the nuclear translocation of NF-κB p65 in LPS-induced RAW 264.7 macrophage cells was detected by confocal microscopy. Moreover, the in vivo anti-inflammatory effect of SMY and its potential mechanisms were further investigated by survival analysis, hematoxylin-eosin staining (H&E), observation of neutrophil migration and quantitative real-time PCR (qRT-PCR) analysis in zebrafish inflammatory models.

RESULTS

SMY reduced the release of IL-6 and TNF-α, inhibited the phosphorylation of IκBα and STAT3 as well as the nuclear translocation of NF-κB p65 in LPS-induced RAW 264.7 cells. Furthermore, the increased survival, decreased infiltration of inflammatory cells and the attenuated migration of neutrophils together suggested the in vivo anti-inflammatory effects of SMY. More importantly, SMY reduced the gene expressions of pro-inflammatory cytokines and suppressed LPS-induced up-regulation of NF-κB, IκBα and STAT3 in zebrafish inflammatory models.

CONCLUSION

SMY exerts significant anti-inflammatory effects with a potential mechanism of inhibiting the NF-κB and STAT3 signal pathways. Our findings suggest a scientific rationale of SMY to treat inflammatory diseases in clinic.

Tribulus terrestris L. Extract Protects against Lipopolysaccharide-Induced Inflammation in RAW 264.7 Macrophage and Zebrafish via Inhibition of Akt/MAPKs and NF-κB/iNOS-NO Signaling Pathways

Inflammation response is a regulated cellular process and excessive inflammation has been recognized in numerous diseases, such as cardiovascular disease, neurodegenerative disease, inflammatory bowel disease, and cancer. Tribulus terrestris L. (TT), also known as Bai Jili in Chinese, has been applied in traditional Chinese medicine for thousands of years while its anti-inflammatory activity and underlying mechanism are not fully elucidated. Here, we hypothesize Tribulus terrestris L. extract (BJL) which presents anti-inflammatory effect, and the action mechanism was also investigated. We employed the transgenic zebrafish line Tg(MPO:GFP), which expresses green fluorescence protein (GFP) in neutrophils, and mice macrophage RAW 264.7 cells as the in vivo and in vitro model to evaluate the anti-inflammatory effect of BJL, respectively. The production of nitric oxide (NO) was measured by Griess reagent. The mRNA expression levels of inflammatory cytokines and inducible nitric oxide synthase (iNOS) were measured by real-time PCR, and the intracellular total or phosphorylated protein levels of NF-κB, Akt, and MAPKs including MEK, ERK, p38, and JNK were detected by western blot. We found that BJL significantly inhibited fin transection or lipopolysaccharide- (LPS-) induced neutrophil migration and aggregation in zebrafish in vivo. In mice macrophage RAW 264.7 cells, BJL ameliorated LPS-triggered excessive release of NO and transcription of inflammatory cytokine genes including tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1 beta (IL-1β). BJL also reduced the LPS-induced elevations of intracellular iNOS and nuclear factor kappa B (NF-κB) which mediate the cellular NO and inflammatory cytokine productions, respectively. Moreover, LPS dramatically increased the phosphorylation of Akt and MAPKs including MEK, ERK, p38, and JNK in RAW 264.7 cells, while cotreatment BJL with LPS suppressed their phosphorylation. Taken together, our data suggested that BJL presented potent anti-inflammatory effect and the underlying mechanism was closely related to the inhibition of Akt/MAPKs and NF-κB/iNOS-NO signaling pathways.

Holistic quality evaluation of Qingwen Baidu Decoction and its anti-inflammatory effects

ETHNOPHARMACOLOGICAL RELEVANCE

Qingwen Baidu Decoction (QBD), a famous traditional Chinese medicine prescription with heat-clearing and detoxifying efficacies, is widely used in the treatment of inflammatory diseases. However, due to lack of holistic quality evaluation research, the further study on the detailed molecular mechanisms of action are still insufficient.

AIM OF THE STUDY

This study aimed to evaluate the overall quality of QBD and to explore the anti-inflammatory effects and associated intracellular signaling pathways.

MATERIALS AND METHODS

a comprehensive method of chemical fingerprint analysis and simultaneous multi-component quantification was firstly developed by high performance liquid chromatography with diode array detector (HPLC-DAD). Similarity analysis, principal component analysis and hierarchical cluster analysis with heatmap were also applied to screen out the markers components in QBD samples. Moreover, its anti-inflammatory effects and mechanisms were further investigated by survival analysis, hematoxylin-eosin staining (H&E), neutrophil observation, quantitative real-time PCR analysis (qRT-PCR), Western blotting and confocal microscopy.

RESULTS

Twenty-one characteristic peaks from 11 herbs were chemically identified in the chromatographic fingerprint. Fifteen quantitative markers from 11 herbs, such as baicalin, wogonoside, geniposidic acid, oxypaeoniflora and so on, were screened out with the aid of chemometrics to further quantitatively assess the quality of QBD. The results of survival analysis, H&E and neutrophil observation in zebrafish inflammatory models consistently showed that QBD exerts potent anti-inflammatory effects in a dose-dependent manner. Additionally, QBD inhibited the activation of NF-κB and STAT3 signal pathways in LPS-induced zebrafish and RAW 264.7 macrophage cells.

CONCLUSION

Collectively, our investigations firstly described the chemical profile of QBD and its possible mechanism of anti-inflammation, which provides a preferred strategy for monitoring the overall quality of QBD and supports its clinical application in treating inflammation-related diseases.

Protective Activities of Dendrobium huoshanense C. Z. Tang et S. J. Cheng Polysaccharide against High-Cholesterol Diet-Induced Atherosclerosis in Zebrafish

Cardiovascular disease is the highest cause of death, and atherosclerosis (AS) is the primary pathogenesis of many cardiovascular diseases. In this study, we aim to investigate the possible pharmaceutical effects of Dendrobium huoshanense C. Z. Tang et S. J. Cheng polysaccharide (DHP) in AS. We fed zebrafish with high-cholesterol diet (HCD) to establish a zebrafish AS model and treated with DHP and observed plaque formation and neutrophil counts under a fluorescence microscope. Next, a parallel flow chamber was utilized to establish low shear stress- (LSS-) induced endothelial cell (EC) dysfunction model. We observed that DHP significantly improved HCD-induced lipid deposition, oxidative stress, and inflammatory response, mainly showing that DHP significantly increased superoxide dismutase (SOD) activity, decreased plaque formation, and decreased neutrophil recruitment and the levels of total cholesterol (TC), triglyceride (TG), malondialdehyde (MDA), and reactive oxygen species (ROS). Furthermore, DHP significantly improved LSS-induced oxidative stress and EC dysfunction. Our results indicated that DHP can exert treatment effects on AS, which may attribute to its hypolipidemic, antioxidant, anti-inflammatory activities and improving LSS-induced EC dysfunction. DHP has promising potential for further development as a functional natural medicine source targeted at AS prevention.