Effects of esculentoside A on autoimmune syndrome induced by Campylobacterjejuni in mice and its modulation on T-lymphocyte proliferation and apoptosis.

Esculentoside A (EsA), a saponin isolated from the root of Phytolacca esculenta, has been reported to exert anti-inflammatory effects in several animal models of acute and chronic inflammation by inhibiting the production and activity of pro-inflammatory cytokines in macrophages and epithelial cells. However, little is known about its modulation on T cells. In the present study, we further investigated its potential in treatment of autoimmune disease and its modulation on T cells, using an experimental autoimmune model established through immunizing mice with Campylobacterjejuni strain CJ-S(131) in Freund's complete adjuvant. Our results demonstrated that EsA administration markedly alleviated the inflammatory injury in liver and kidney of model mice, decreased the anti-CD3/CD28-stimulated proliferation of splenocytes and lymph node cells, and reduced the percentage of CD3+, CD4+, and CD8+ lymphocytes in peripheral blood. Furthermore, we demonstrated that EsA induced apoptosis in ConA-activated thymocytes but not in non-activated thymocytes. Gene expression analysis revealed that EsA up-regulated the expression of a group of pro-apoptotic genes more profoundly in Con A-activated thymocytes than in non-activated thymocytes. EsA-affected pro-apoptotic genes included those involved in Fas induction, p53 activation, redox metabolism, calcium- and glucocorticoid-induced apoptosis signals, suggesting that EsA may modulate multiple apoptotic signal pathways in activated T cells. Taken together, our findings suggest that EsA may be useful for the treatment of autoimmune disease through modulation on T cell-mediated adaptive immunity.

Protective effect of esculentoside A on radiation-induced dermatitis and fibrosis.

PURPOSE: To investigate the effect of esculentoside A (EsA) on radiation-induced cutaneous and fibrovascular toxicity and its possible molecular mechanisms, both in vivo and in vitro. METHODS AND MATERIALS: Mice received drug intervention 18 hours before 30 Gy to the right hind leg. Alterations in several cytokines expressed in skin tissue 2 days after irradiation were determined by ELISA. Early skin toxicity was evaluated 3 to 4 weeks after irradiation by skin scoring, and both tissue contraction and expression of TGF-beta1 were determined for soft-tissue fibrosis 3 months after irradiation. In vitro, the effect of EsA on radiation-induced nitric oxide (NO) and cytokine production in different cell types was measured by application of 2, 4, and 8 Gy. RESULTS: In vivo, EsA reduced levels of IL-1alpha, MCP-1, VEGF, and TGF-beta1 in cutaneous tissue and reduced soft-tissue toxicity. In vitro, EsA inhibited the IL-1alpha ordinarily produced after 4 Gy in A431 cells. In Raw264.7 cells, EsA reduced levels of IL-1alpha, IL-1beta, and NO production costimulated by radiation and lipopolysaccharide (LPS). In L-929 cells, EsA inhibited VEGF, TNF, and MCP-1 production at 2, 4, and 8 Gy. CONCLUSIONS: Esculentoside A protects soft tissues against radiation toxicity through inhibiting the production of several proinflammatory cytokines and inflammatory mediators in epithelial cells, macrophages, fibroblasts, and skin tissue.

Effects of esculentoside A on production of interleukin-1, 2, and prostaglandin E2.

AIM: To investigate the influence of esculentoside A (EsA) on immunological function and its mechanism of anti-inflammation. METHODS: Interleukin-1 production was measured by thymocyte co-stimulating assay; the radioactivity of [(3)H]arachidonic acid (AA) was used to evaluate the release of AA; prostaglandin E2 production was measured with radioimmunoassay (RIA); IL-2 and IFN-gamma were detected by ELISA method. RESULTS: EsA (3-12 micromol/L)could potently inhibit the production of IL-1 and PGE(2) from both silent and LPS induced macrophages. EsA had no significant effect on the release of AA from murine macrophages. EsA could inhibit the production of IL-2 from murine lymphocytes induced by ConA, but not affect the production from silent lymphocytes. EsA showed no effect on the production of IFN-gamma from both silent and ConA induced lymphocytes. CONCLUSION: EsA could affect the immunological function through inhibiting the production of IL-2 from activated splenocytes and the inhibition of production of IL-1 and PGE(2) might be one of the anti-inflammation mechanisms of EsA.

[Effect of esculentoside A on cellular adhesion].

AIM: To investigate the anti-inflammatory mechanism of esculentoside A (EsA) and to observe the effects of EsA on cellular adhesion between human umbilical vein endothelial cell (VEC304) and human neutrophil and to further observe the mRNA expression of intercellular adhesion molecule-1 (ICAM-1) and cluster of differentiation 18(CD18). METHODS: The hemocyte counting method was used for assaying the adhesion rate between VEC304 and neutrophil. The RT-PCR method was used for measuring the mRNA expression of ICAM-1 and CD18. RESULTS: The adhesion rate between VEC304 and neutrophil was increased with treatment of lipopolysaccharide(LPS). EsA (3 - 12 x 10(-6) mumol.L-1) was shown to inhibit the high cellular adhesion induced by LPS. A further investigation of adhesion molecules mRNA expression was undertaken using semi-quantitative reverse transcribed polymerase chain reaction (RT-PCR). The results of RT-PCR from VEC304 and human neutrophil treating with LPS showed that ICAM-1 and CD18 mRNA expressions were higher than those of normal cells, while this increased expression of ICAM-1 and CD18 mRNA was remarkably attenuated by the addition of EsA. CONCLUSION: EsA was found to inhibit the increased adhesion rate induced by LPS. Moreover, LPS induced high expression of ICAM-1 and CD18 was inhibited with treatment of EsA. It might be involved in the mechanisms of anti-inflammation of EsA.

Effect of esculentoside A on autoimmunity in mice and its possible mechanisms.

AIM: To investigate the influence of esculentoside A (EsA) on autoimmunity in mice and its possible mechanisms. METHODS: The level of anti-ds DNA antibody, proliferation of lymphoid cells, and inflammation by pathologic section of joint in mice were examined. The autoimmunity model is made through immunizing mice with formaldehyde treated Campylobacter jejuni strain CJ-S131 and Freund's complete adjuvant. The apoptosis of T cell was analyzed through morphology and flow cytometry (FACS). The expression of ICAM-1 mRNA in human umbilical vein endothelial cell line (ECV304) was determined by coupled reverse transcription and PCR amplification (RT-PCR). RESULTS: EsA could potently lower the level of anti-ds DNA antibody, inhibit the proliferation of lymphoid cells, and ameliorate inflammation in the joint of model mouse. The apoptosis of thymocyte activated by ConA was markedly accelerated while the expression of ICAM-1 mRNA in ECV304 was decreased by EsA. CONCLUSION: EsA has the positive curative effect on autoimmunity in a mouse model, which may function through inhibition of expression of ICAM-1 mRNA in ECV304 and acceleration of thymocyte apoptosis.