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Biomedical subjects

Yuan-chao Li

Publications and source records attributed to Yuan-chao Li.

6 recordsLinked to original sources
PubMed2006

Suppression of (5R)-5-hydroxytriptolide (LLDT-8) on allograft rejection in full MHC-mismatched mouse cardiac transplantation.

BACKGROUND: (5R)-5-hydroxytriptolide (LLDT-8) is a new compound derived from triptolide, which is the major immunosuppressive fraction of Tripterygium wilfordii Hook. F (TWHF). Studies in vitro and in vivo have demonstrated that LLDT-8 had potent immunosuppressive activities. Here we tested LLDT-8 in major histocompatibility complex (MHC)-mismatched cardiac transplantation and investigated the mechanisms underlying the prevention of transplant rejection. METHODS: LLDT-8 was administered orally to recipients in Balb/c to C57BL/6 murine cardiac transplantation model. Allograft survival after transplantation was recorded in recipients. The T cell immunity and cytokine production were observed. Histological analysis was performed. The chemokine and its receptor were analyzed by reverse transcriptase-polymerase chain reaction on cardiac graft RNA. RESULTS: LLDT-8 administered orally significantly induced the survival prolongation of allogeneic cardiac graft. Histological results showed that LLDT-8 well preserved myocardium and significantly reduced infiltration of the graft with inflammatory cells. LLDT-8 decreased IL-2 production in recipient splenocytes stimulated by concanavalin A (ConA) ex vivo. LLDT-8 significantly inhibited the immunoreactivity of recipient to specific donor alloantigens, but preserved immunity to third-party alloantigens and mitogen. However, the flow cytometry analysis of the proportion of CD4+, CD8+ T cell subgroup in recipient spleens showed LLDT-8 had a normalizing effect on the splenic lymphocytes population. LLDT-8 decreased CC chemokine receptor 5 (CCR5) and their ligands macrophage inflammatory protein 1 alpha (MIP-1alpha) and beta (MIP-1beta) mRNA expressions in allografts. CONCLUSION: The results outline the great potential of LLDT-8 as a therapeutic tool in transplant rejection.

Animals↗
PubMed2006

(5R)-5-hydroxytriptolide inhibits IFN-gamma-related signaling.

AIM: (5R)-5-hydroxytriptolide (LLDT-8) displayed anti-arthritis and anti-allogenic transplantation rejection activities in our previous studies. Here, we aim to further clarify the effect of LLDT-8 on the pro-inflammatory cytokine IFN-gamma. METHODS: T cells were activated with anti-CD3 antibody or concanavalin A (ConA). The expression of cell surface molecules was detected with flow cytometry. Cells were labeled with carboxyfluorescein diacetate succinimidyl ester (CFSE) to test cell division. IFN-gamma production was determined by enzyme-linked immunosorbent assay. Cell proliferation was evaluated by [3H]-thymidine uptake. Mice were immunized with ovalbumin to assess the in vivo immune response. RT-PCR and Real-time PCR were applied to determine the mRNA expression. The protein phosphorylation levels were detected by Western immunoblot assay. RESULTS: LLDT-8 at 100 nmol/L did not change the CD25, CD69, and CD154 expressions in anti-CD3-stimulated T cells. LLDT-8 markedly blocked the cell division of CD4 and CD8 T cells after ConA stimulation. LLDT-8 inhibited T cell-derived IFN-gamma production. Moreover, LLDT-8 suppressed the ovalbumin-specific T cell proliferation and IFN-gamma generation. In anti-CD3-activated T cells, LLDT-8 abrogated the mRNA expression of signal transducer and activator of transcription1 (STAT1), T-box transcription factor, IL-12 receptor beta2, STAT4, and interferon regulatory factor 1 in the IFN-gamma expression pathway. Western blot analysis showed that LLDT-8 blocked the phosphorylation levels of extracellular signal-regulated kinase, stress-activated protein kinase (SAPK)/c-Jun N-terminal kinase, and p38 mitogen-activated protein kinase in anti-CD3 plus anti-CD28-activated T cells. In addition, LLDT-8 reduced the transcripts of macrophage inflammatory protein (Mip)-1alpha, Mip-1beta, regulated upon activation normally T-cell expressed and secreted, inducible protein-10, IFN-inducible T cell a chemoattractant, and monokine induced by IFN-gamma in IFN-gamma-stimulated murine macrophage cell line Raw 264.7 cells. CONCLUSION: LLDT-8 was a potential inhibitor for IFN-gamma-associated signaling.

Animals↗
PubMed2005

[Isolation and structure identification of chemical constituents from Anabasis brevifolia].

AIM: To study the chemical consitituents of the n-butanol-extracts of Anabasis salsa and Various chromatographic techniques were used to the chloroform-extract of Anabasis brevifolia. METHODS: separate and purify the constituents. Their physico-chemical properties and spectral data were used to elucidate their structures. RESULTS: Five compounds were isolated and identified as 2-O-beta-D-glucopyranosyloxy-4,6-dimethoxy phenylenthanone (1), 2-O-(2)-beta-D-glucopyranosyloxy-4, 6-dimethoxy phenylenthanone (2), 3-methyl-but-2-enoic acid-[2-(4-methoxy phenyl)-ethyl]-amide (3), 5,6,7,2'-tetramethoxy isoflavonoid (4), 2'-hydroxy-5,6,7-trimethoxyisoflavonoid (5). CONCLUSION: Compounds 2, 3, and 5 are new compounds. And the others were isolated from Anabasis L. for the first time.

Chenopodiaceae↗
PubMed2002

[Studies on the chemical constituents of Lycianthes biflora].

AIM: To study the chemical constituents of Lycianthes biflora. METHODS: Column chromatography was used to separate the chemical constituents. IR, MS, 1HNMR, 13CNMR and 2D-NMR technique were used to determine the structures of the isolated constituents. RESULTS: Five compounds were isolated from this plant. Their structures were identified to be bifloride A (1), N-trans-cinnamoyltyramine (2), liquiritigenin (3), N-trans-p-coumaroyloctopamine (4), 1-O-beta-D-glucopyranosyl-2-N-2'-hydroxypalmitoyl-sphinga-4- trans-8-trans-dienine (5). CONCLUSION: Compounds 1 and 2 are new compounds, the others were isolated from this plant for the first time. Compound 2 showed inhibitory effects on P-388.

4-Butyrolactone↗
PubMed2002

[Isolation and structure of wilfordlonging from Tripterygium wilfordii Hook. f].

AIM: To study the chemical composition of Tripterygirm wilfordii Hook. f. METHODS: Colunm chromatography was used to separate the chemical constituents. UV, IR, MS, HRMS, 1HNMR, 13CNMR (COM and OFR), 1H-1H COSY, 1H-13C COSY, NOESY and COLOC spectra were used to determine the structures of the isolated constituents. RESULTS: Two sesquiterpene alkaloids were isolated and their structures were elucidated as wilforgine and wilfordlongine on the basis of spectral evidence. CONCLUSION: Wilfordclonine is a new sesquiterpene alkaloid.

Lactones↗