Bocui Song

Salidroside attenuates LPS-induced pro-inflammatory cytokine responses and improves survival in murine endotoxemia

Salidroside is a major component isolated from the Rhodiola rosea. In the present study, we investigated the anti-inflammatory effects of salidroside on cytokine production by lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages in vitro, and the results showed that salidroside reduced tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) secretions. This inspired us to further study the effects of salidroside in vivo. Salidroside significantly attenuated TNF-α, IL-1β and IL-6 productions in serum from mice challenged with LPS, and consistent with the results in vitro. In the murine model of endotoxemia, mice were treated with salidroside prior to or after LPS challenge. The results showed that salidroside significantly increased mouse survival. Further studies revealed that salidroside could downregulate LPS-induced nuclear transcription factor-қB (NF-қB) DNA-binding activation and ERK/MAPKs signal transduction pathways production in RAW 264.7 macrophages. These observations indicated that salidroside modulated early cytokine responses by blocking NF-қB and ERK/MAPKs activation, and thus, increased mouse survival. These effects of salidroside may be of potential usefulness in the treatment of inflammation-mediated endotoxemia.

Protective effects of salidroside from Rhodiola rosea on LPS-induced acute lung injury in mice.

Salidroside is a major component extracted from Rhodiola rosea. In this study, we investigated protective effects of salidroside on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice. In the mouse model, we found that pretreatment with a single 120 mg/kg dose of salidroside prior to the administration of intratracheal LPS induced a significant decrease in the W/D ratio and mouse myeloperoxidase activity of lung, reduction protein concentration, the number of total cells, neutrophils and macrophages in the bronchoalveolar lavage fluid. In addition, salidroside also inhibited the production of several inflammatory cytokines, including tumor necrosis factor-α, interleukin-6 (IL-6) and IL-1β, and the NF-κB DNA-binding activation after LPS challenge. These results indicated that salidroside possess a protective effect on LPS-induced ALI in mice.

Immunosuppressive activity of daphnetin, one of coumarin derivatives, is mediated through suppression of NF-κB and NFAT signaling pathways in mouse T cells.

Daphnetin, a plant-derived dihydroxylated derivative of coumarin, is an effective compound extracted from a plant called Daphne Korean Nakai. Coumarin derivates were known for their antithrombotic, anti-inflammatory, and antioxidant activities. The present study was aimed to determine the immunosuppressive effects and the underlying mechanisms of daphnetin on concanavalin A (ConA) induced T lymphocytes in mice. We showed that, in vitro, daphnetin suppressed ConA-induced splenocyte proliferation, influenced production of the cytokines and inhibited cell cycle progression through the G0/G1 transition. The data also revealed that daphnetin could down-regulate activation of ConA induced NF-κB and NFAT signal transduction pathways in mouse T lymphocyte. In vivo, daphnetin treatment significantly inhibited the 2, 4- dinitrofluorobenzene (DNFB) -induced delayed type hypersensitivity (DTH) reactions in mice. Collectively, daphnetin had strong immunosuppressive activity both in vitro and in vivo, suggesting a potential role for daphnetin as an immunosuppressive agent, and established the groundwork for further research on daphnetin.

Gossypol suppresses mouse T lymphocytes via inhibition of NFκB, NFAT and AP-1 pathways.

Abstract Gossypol is a kind of yellow polyphenolic compounds extracted from root stem and seed of the cotton plant. In the present study, we investigated its immunosuppressive mechanism by using BALB/c mouse T lymphocytes in vitro. When mouse splenocytes was incubated with gossypol, the extract effectively suppress the overproduction of the cell stimulated by concanavalin A (ConA) in a dose manner. This inhibitive activity was mainly due to interfering Th1 and Th2 cytokines production and decreasing CD4+ T cell populations and ratio of CD4+/CD8+. Furthermore, we also showed that signal transduction via NF-κB, NFAT and AP-1 are critical to the ConA-induced T cell activation in mice. The data revealed that gossypol could down-regulate activation of ConA-induced NF-κB, NFAT and AP-1 signal transduction pathways in mouse T lymphocyte. These observations indicated that gossypol exhibited immunosuppressive effects by inhibition T lymphocyte activation in vitro.

Suppressive effects of fisetin on mice T lymphocytes in vitro and in vivo

BACKGROUND Most of the immunosuppressive drugs have satisfactory therapeutic effects on organ transplantation and autoimmune disease. However, their clinical application is limited by side effects. Therefore, new and safe immunosuppressive drugs against acute and chronic rejections are eagerly awaited. Fisetin, a flavonoid present in various types of vegetables and fruits, has few side effects and low level of toxicity, which would be a desirable clinical feature. In the present study, we investigated the immunosuppressive effects and underlying mechanisms of fisetin against T-cell activation in vitro and in vivo. METHODS We measured the effect of fisetin on T-lymphocyte proliferation, T-cell subsets, cell cycle progression, cytokine production, and nuclear factor activation in vitro, as well as its influence on T cell-mediated delayed-type hypersensitivity reaction in vivo. RESULTS In vitro, the results showed that fisetin significantly suppressed mouse splenocytes proliferation, Th1 and Th2 cytokine production, cell cycle and the ratio of CD4(+)/CD8(+) T cells. Furthermore, fisetin exerts an immunosuppressive effect in mouse T lymphocytes through the suppression of nuclear factor kappa B activation and nuclear factor of activated T cells signaling in a dose-dependent manner. In vivo, fisetin treatment also significantly inhibited the dinitrofluorobenzene-induced delayed-type hypersensitivity reactions in mice. CONCLUSIONS Fisetin had strong immunosuppressive activity in vitro and in vivo, suggesting a potential role for fisetin as an immunosuppressive agent.

Investigation of effects of farrerol on suppression of murine T lymphocyte activation in vitro and in vivo.

Farrerol, a new type of 2,3-dihydro-flavonoid, has been isolated from the leaves of Rhododendron dauricum L. In the present study, we found that farrerol exerted potent immunosuppressive effects on murine T cells both in vitro and in vivo. In vitro, farrerol markedly suppressed concanavalin A (ConA)-induced lymphocyte proliferation, Th1 and Th2 cytokine production, cluster of differentiation 4-positive (CD4(+)) T cell populations, and the ratio of CD4(+)/cluster of differentiation 8-positive (CD8(+)) T cells. Moreover, farrerol significantly inhibited the T cell-mediated delayed-type hypersensitivity (DTH) reaction in vivo. In addition, we investigated signal transduction mechanisms to determine the effects of farrerol by Western blotting. The data revealed that farrerol could downregulate the activation of the nuclear factor κB (NF-қB) and nuclear factor of activated T cells 2 (NFAT2) signal transduction pathways. These findings suggested that farrerol has potential effects on the regulation of the immune system and could be developed as a practicable immunosuppressive compound.

Immunosuppressive activity of alpinetin on activation and cytokines secretion of murine T lymphocytes.

Abstract Alpinetin, a flavonoid compound extracted from the seeds of Alpinia katsumadai Hayata, has been known to possess antibacterial, anti-inflammatory and other important therapeutic activities. In the current study, we investigated alpinetin for its immunosuppressive effect on activation and cytokines secretion of murine T lymphocytes. The data showed that alpinetin markedly suppressed ConA-induced murine splenocyte proliferation, Th1/Th2 cytokines production, CD4+ T-cell populations and ratio of CD4+/CD8+. This inspired us to further study the effects of alpinetin in vivo. The results showed that administration of alpinetin suppressed T-cell-mediated delayed-type hypersensitivity reaction in mice. In addition, we studied signal transduction pathways about T-cell activation on puried murine T lymphocytes by Western-blot assay. The data revealed that alpinetin could shock the activation of NF-κB, NFAT2 signal transduction pathways. These observations indicated that alpinetin have potential effects in downregulating the immune system and might be developed as a useful immunosuppressive agent in treating undesired immune responses.

Tyrosol exhibits negative regulatory effects on LPS response and endotoxemia.

Tyrosol, a phenolic compound, was isolated from wine, olive oil and other plant-derived products. In the present study, we first investigated the negative regulatory effects of tyrosol on cytokine production by lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages in vitro, and the results showed that tyrosol reduced tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) secretion. This inspired us to further study the effects of tyrosol in vivo. Tyrosol significantly attenuated TNF-α, IL-1β and IL-6 production in serum from mice challenged with LPS, and consistent with the results in vitro. In the murine model of endotoxemia, mice were treated with tyrosol prior to or after LPS challenge. The results showed that tyrosol significantly increased mice survival. We further investigated signal transduction ways to determine how tyrosol works. The data revealed that tyrosol shocked LPS-induced mitogen activated protein kinases (MAPKs) and nuclear transcription factor-κB (NF-κB) signal transduction pathways in RAW 264.7 macrophages. These observations indicated that tyrosol exerted negative regulatory effects on LPS response in vitro and in vivo through suppressing NF-κB and p38/ERK MAPK signaling pathways.

Inhibitory Effects of Salidroside on Nitric Oxide and Prostaglandin E2 Production in Lipopolysaccharide-Stimulated RAW 264.7 Macrophages

The aim of this study was to evaluate the effect of salidroside on lipopolysaccharide (LPS)-induced nitric oxide (NO) and prostaglandin E₂ (PGE₂) production in RAW 264.7 macrophages and related anti-inflammatory mechanism. PGE₂ production was measured by enzyme-linked immunosorbent assay (ELISA); NO production was tested by Griess reagent. Inducible nitric oxidesynthase (iNOS) and COX-2 were determined by RT-PCR and Western blot analysis; IκB and P-IκB protein express were detected by Western blot analysis; cytosolic free Ca²⁺ ([Ca²⁺](i)) was measured by a fluorescent microscope. The data showed salidroside inhibited LPS-induced NO and PGE₂ production and reduced iNOS and COX-2 protein expression in RAW 264.7 macrophages. Consistent with these observations, salidroside inhibited LPS-induced cytosolic free Ca²⁺ concentration ([Ca²⁺](i)) elevation. In addition, we further investigated signal transduction mechanisms and found that the activation of NF-κB was suppressed by salidroside in a dose-dependent manner. These results suggest that salidroside suppresses NO and PGE₂ production by inhibiting iNOS and COX-2 protein expression, level of [Ca²⁺](i), and activation of NF-κB signal transduction pathway.

The inhibition of 2,3-dichloro-1-propanol on T cell in vitro and in vivo.

2,3-Dichloro-1-propanol (2,3-DCP) is a member of a group of chemicals known as chloropropanols. Currently, immunotoxicity of 2,3-DCP has not been reported. In the present study, we studied its inhibitory effects on T cell both in vivo and in vitro. The results showed that 2,3-DCP markedly inhibited ConA-induced splenocyte proliferation, Th1 and Th2 cytokine production, CD4(+) T cell populations, and the ratio of CD4(+)/CD8(+) T cells and cell cycle arrest in vitro. In addition, 2,3-DCP markedly suppressed DNFB-induced T-cell-mediated delayed-type hypersensitivity (DTH) reaction in mice. Furthermore, Western blot was used to study how 2,3-DCP affects signal transduction mechanisms. The data revealed that 2,3-DCP could down regulate activation of ConA-induced NF-κB and NFAT signal transduction pathways. These observations indicated that 2,3-DCP exhibited negative regulatory effects by directly suppressing T-cell-mediated immune responses in vitro and in vivo.