Jianping Zuo

Anti-hepatitis B virus activity of chlorogenic acid, quinic acid and caffeic acid in vivo and in vitro.

Chlorogenic acid and its related compounds are abundant plant polyphenols that have a diverse antiviral activity. In this study, HepG2.2.15 cells and duck hepatitis B virus infection model were used as in vitro and in vivo models to evaluate their anti-HBV activity. In the cell model, all the three compounds inhibited HBV-DNA replication as well as HBsAg production. Chlorogenic acid and caffeic acid also reduced serum DHBV level in DHBV-infected duckling model. Moreover, the anti-HBV activity of crude extracts of coffee beans, which have a high content of chlorogenic acid, was studied. Both the extracts of regular coffee and that of decaffeinated coffee showed inhibitory effect on HBV replication.

Nucleocapsid protein of SARS coronavirus tightly binds to human cyclophilin A

Abstract Severe acute respiratory syndrome coronavirus (SARS-CoV) is responsible for SARS infection. Nucleocapsid protein (NP) of SARS-CoV (SARS_NP) functions in enveloping the entire genomic RNA and interacts with viron structural proteins, thus playing important roles in the process of virus particle assembly and release. Protein–protein interaction analysis using bioinformatics tools indicated that SARS_NP may bind to human cyclophilin A (hCypA), and surface plasmon resonance (SPR) technology revealed this binding with the equilibrium dissociation constant ranging from 6 to 160nM. The probable binding sites of these two proteins were detected by modeling the three-dimensional structure of the SARS_NP–hCypA complex, from which the important interaction residue pairs between the proteins were deduced. Mutagenesis experiments were carried out for validating the binding model, whose correctness was assessed by the observed effects on the binding affinities between the proteins. The reliability of the binding sites derived by the molecular modeling was confirmed by the fact that the computationally predicted values of the relative free energies of the binding for SARS_NP (or hCypA) mutants to the wild-type hCypA (or SARS_NP) are in good agreement with the data determined by SPR. Such presently observed SARS_NP–hCypA interaction model might provide a new hint for facilitating the understanding of another possible SARS-CoV infection pathway against human cell.

Investigation of the immunosuppressive activity of artemether on T-cell activation and proliferation

Artemisinin and its derivatives exhibit potent immunosuppressive activity. The purpose of the current study was to examine the immunosuppressive activity of artemether directly on T lymphocytes and to explore its potential mode of action.

SM905, an artemisinin derivative, inhibited NO and pro-inflammatory cytokine production by suppressing MAPK and NF-κB pathways in RAW 264.7 macrophages

AbstractAim:To elucidate the anti-inflammatory potentials and underlying mechanisms of SM905, a novel artemisinin derivative, in lipopolysaccharide (LPS)-stimulated murine macrophage RAW 264.7 cells.Methods:Nitric oxide (NO) generation, cytokine production, and the protein expression levels of inducible nitric-oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were examined using a Griess assay, an enzyme-linked immunosorbent assay (ELISA) and a Western blotting assay, respectively. The mRNA expression was measured using real-time PCR. The phosphorylation of extracellular signal-regulated kinase1/2 (ERK1/2), p38, c-jun N-terminal kinase (JNK), and the degradation of IκBα were assessed by Western blotting analysis. The nuclear translocation of nuclear factor-κB (NF-κB) was observed using confocal microscopy.Results:Pretreatment with SM905 (0, 0.1, 1, and 10 μmol/L) suppressed LPS-induced NO, TNF-α, IL-1β, and IL-6 production, and decreased both protein and mRNA levels of iNOS and COX-2. The mRNA expression of LPS receptor Toll-like receptor 4 (TLR4) and myeloid differentiation protein-2 (MD-2) was not changed, while LPS-induced CD14 expression was slightly reduced after SM905 treatment. SM905 markedly decreased the activation of ERK1/2, p38 and JNK suppressed the degradation of IκBα, but did not modify the expression of interferon regulatory factor-1 (IRF-1), signal transducer and activator of transcription 1 (STAT1) or interferon-inducible protein-10 (IP-10). By using confocal microscopy, we further observed that NF-κB was correspondingly inhibited in SM905-treated cells.Conclusion:SM905 inhibited NO and pro-inflammatory cytokine production in LPS-stimulated RAW 264.7 cells and these effects are at least partially mediated through suppression of the MAPK and NF-κB signaling pathways.

Oral administration of artemisinin analog SM934 ameliorates lupus syndromes in MRL/lpr mice by inhibiting Th1 and Th17 cell responses

OBJECTIVE SM934, an artemisinin derivative, possesses potent antiproliferative and antiinflammatory properties. The aim of this study was to examine the effects and explore the mechanisms of SM934 to treat autoimmune disease in lupus-prone female MRL/lpr mice. METHODS In vitro, the effects of SM934 on the activation of polyclonal CD4+ T cells and the differentiation of naive CD4+ T cells were examined. In vivo, the preventative or therapeutic effects of SM934 in MRL/lpr mice were investigated. Ex vivo, the mechanisms of treatment were explored according to the immunologic correlates of disease. RESULTS In vitro, SM934 inhibited interferon-γ (IFNγ) and interleukin-17 (IL-17) production from polyclonal CD4+ T cells activated by T cell receptor engagement and the differentiation of naive CD4+ T cells into Th1 and Th17 cells, but not Treg cells. In vivo, 12-week-old MRL/lpr mice treated with SM934 for 4 weeks showed significantly ameliorated proteinuria and renal lesion severity; decreased levels of blood urea nitrogen, serum IFNγ, and serum anti-double-stranded DNA antibodies; decreased spleen size; and a lower percentage of CD3+B220+CD4-CD8- T cells; 16-week-old MRL/lpr mice treated with SM934 for 8 weeks avoided severe proteinuria and survived longer. Ex vivo, SM934 treatment elevated the percentage of Treg cells, inhibited the development of Th1 and Th17 cells, and impeded the comprehensive activation of STAT-1, STAT-3, and STAT-5 proteins in splenocytes. CONCLUSION Taken together, the results of this study demonstrated that the artemisinin analog SM934 had therapeutic effects in lupus-prone female MRL/lpr mice by inhibiting both Th1 cell and Th17 cell responses. Moreover, this study indicated that both IFNγ and IL-17 are required for the elicitation and development of murine lupus.

Discovery of novel small molecule inhibitors of dengue viral NS2B-NS3 protease using virtual screening and scaffold hopping.

By virtual screening, compound 1 was found to be active against NS2B-NS3 protease (IC(50) = 13.12 ± 1.03 μM). Fourteen derivatives (22) of compound 1 were synthesized, leading to the discovery of four new inhibitors with biological activity. In order to expand the chemical diversity of the inhibitors, small-molecule-based scaffold hopping was performed on the basis of the common scaffold of compounds 1 and 22. Twenty-one new compounds (23, 24) containing quinoline (new scaffold) were designed and synthesized. Protease inhibition assays revealed that 12 compounds with the new scaffold are inhibitors of NS2B-NS3 protease. Taken together, 17 new compounds were discovered as NS2B-NS3 protease inhibitors with IC(50) values of 7.46 ± 1.15 to 48.59 ± 3.46 μM, and 8 compounds belonging to two different scaffolds are active to some extent against DENV based on luciferase reporter replicon-based assays. These novel chemical entities could serve as lead structures for discovering therapies against DENV.

Toll-like receptors: potential targets for lupus treatment.

Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by the loss of tolerance to self-nuclear antigens. Accumulating evidence shows that Toll-like receptors (TLRs), previously proven to be critical for host defense, are implicated in the pathogenesis of autoimmune diseases by recognition of self-molecules. Genome-wide association studies, experimental mouse models and clinical sample studies have provided evidence for the involvement of TLRs, including TLR2/4, TLR5, TLR3 and TLR7/8/9, in SLE pathogenesis. A number of downstream proteins in the TLR signaling cascade (such as MyD88, IRAKs and IFN-α) are identified as potential therapeutic targets for SLE treatment. Numerous antagonists targeting TLR signaling, including oligonucleotides, small molecular inhibitors and antibodies, are currently under preclinical studies or clinical trials for SLE treatment. Moreover, the emerging new manipulation of TLR signaling by microRNA (miRNA) regulation shows promise for the future treatment of SLE.

Immunosuppressive pregnane glycosides from Periploca sepium and Periploca forrestii

Nine pregnane glycosides containing peroxy functions in their sugar moieties (1-5 and 11-14), five oligosaccharides (6-10), six pregnane glycosides (15-20), and five cardiac glycosides (21-25) were isolated from the root barks of Periploca sepium Bge. (Asclepiadaceae) and the roots of Periploca forrestii Schltr. (Asclepiadaceae), two traditional Chinese medicines used for the treatment of rheumatoid arthritis. Among them, 1-8 are hitherto unknown. Their structures were characterized on the basis of spectroscopic analyses. In pharmacological testing, compounds 1-5 and 11-14 were found to exhibit inhibitory activity against the proliferation of T lymphocyte in vitro with IC50 values ranging from 0.29microM to 1.97microM, while the other components showed no significant inhibitory activity.

COX-2 inhibitors ameliorate experimental autoimmune encephalomyelitis through modulating IFN-γ and IL-10 production by inhibiting T-bet expression

The COX-2 inhibitors Rofecoxib (Rof) and Lumiracoxib (Lum) were evaluated in experimental autoimmune encephalomyelitis (EAE), the model of multiple sclerosis (MS). Administration of Rof and Lum significantly reduced the incidence and severity of EAE, which was associated with the inhibition of MOG 35-55 lymphocyte recall response, anti-MOG 35-55 T cell responses, and modulation of cytokines production. In vitro Rof and Lum inhibited primary T cells proliferation and modulated cytokine production. These findings highlight the fact that Rof and Lum likely prevents EAE by modulating Th1/Th2 response, and suggest its utility in the treatment of MS and other autoimmune diseases.

Eriocalyxin B ameliorates experimental autoimmune encephalomyelitis by suppressing Th1 and Th17 cells

Eriocalyxin B (EriB), a diterpenoid isolated from Isodon eriocalyx, was previously reported to have antitumor effects via multiple pathways, and these pathways are related to immune responses. In this study, we demonstrated that EriB was efficacious in experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis. Treatment with EriB led to amelioration of EAE, which correlated with reduced spinal cord inflammation and demyelination. EriB treatment abolished encephalitogenic T-cell responses to myelin oligodendrocyte glycoprotein in an adoptive transfer EAE model. The underlying mechanism of EriB-induced effects involved inhibition of T helper (Th) 1 and Th17 cell differentiation through Janus Kinase/Signal Transducer and Activator Of Transcription and Nuclear factor-κB signaling pathways as well as elevation of reactive oxygen species. These findings indicate that EriB exerts potent antiinflammatory effects through selective modulation of pathogenic Th1 and Th17 cells by targeting critical signaling pathways. The study provides insights into the role of EriB as a unique therapeutic agent for the treatment of autoimmune diseases.