Stephanthraniline A suppressed CD4(+) T cell-mediated immunological hepatitis through impairing PKCθ function

A novel dibenzofuran from endophytic fungus Mycosphaerella nawae preferentially inhibits CD4+ T cell activation and proliferation

AIM

To obtain promising immunosuppressants from endophytic fungus.

METHODS AND RESULTS

The endophytic fungus Mycosphaerella nawae (ZJLQ129) was isolated from the plant Smilax china L. and its secondary metabolites extracted and fractionated through column chromatography. The metabolites were further modified by a derivatization reaction with ammonium hydroxide. After isolation and derivatization, a new dibenzofuran named as (+)isomycousnine enamine (iME) was obtained. The structures of the derivatives were determined based on chemical evidences and extensive spectroscopic methods including 2D-NMR, DEPT and HRESI-MS spectra. The immune activities of iME were first evaluated on the proliferation and cytokines (IL-2 and IFN-γ) production of T and B cells by using MTT and ELISA methods, respectively. Then, its effects on the proliferation of T cell subsets (CD4⁺ and CD8⁺ T cells), as well as CD25 and CD69 expressions were also determined by flow cytometry. Finally, by using Cytometric Bead Array (CBA), the impacts of iME on the secretion of Th1/Th2/Th17 cytokines from purified CD4⁺ T cells were assayed. The results showed that iME not only selectively suppressed the immune responses of T cells, but also preferentially inhibited the activation and proliferation of CD4⁺ T cells.

CONCLUSION

A novel dibenzofuran derived from endophytic fungus Mycosphaerella nawae preferentially inhibits CD4⁺ T cell activation and proliferation.

SIGNIFICANCE AND IMPACT OF THE STUDY

This work obtained iME, a new dibenzofuran derived from endophytic fungus. iME has the capacity to inhibit CD4⁺ T cell activation and therefore is a novel potential immunosuppressant for development in the future.

Summary of Natural Products Ameliorate Concanavalin A-Induced Liver Injury: Structures, Sources, Pharmacological Effects, and Mechanisms of Action

Liver diseases represent a threat to human health and are a significant cause of mortality and morbidity worldwide. Autoimmune hepatitis (AIH) is a progressive and chronic hepatic inflammatory disease, which may lead to severe complications. Concanavalin A (Con A)-induced hepatic injury is regarded as an appropriate experimental model for investigating the pathology and mechanisms involved in liver injury mediated by immune cells as well as T cell-related liver disease. Despite the advances in modern medicine, the only available strategies to treat AIH, include the use of steroids either solely or with immunosuppressant drugs. Unfortunately, this currently available treatment is associated with significant side-effects. Therefore, there is an urgent need for safe and effective drugs to replace and/or supplement those in current use. Natural products have been utilized for treating liver disorders and have become a promising therapy for various liver disorders. In this review, the natural compounds and herbal formulations as well as extracts and/or fractions with protection against liver injury caused by Con A and the underlying possible mechanism(s) of action are reviewed. A total of 53 compounds from different structural classes are discussed and over 97 references are cited. The goal of this review is to attract the interest of pharmacologists, natural product researchers, and synthetic chemists for discovering novel drug candidates for treating immune-mediated liver injury.

A novel polysaccharide from Dendrobium devonianum serves as a TLR4 agonist for activating macrophages

Dendrobium devonianum has been used as herbal medicines and nutraceutical products since ancient time in China. However, its chemical composition and pharmacological mechanisms are not fully known. In present studies, by chemical purification and characteristic identification, we discovered a novel polysaccharide from D. devonianum, which was designated as DvP-1 with molecular weights of 9.52 × 10⁴ Da. DvP-1 is a homogeneous heteropolysaccharide consisting of D-mannose and d-glucose in the molar ration of 10.11: 1. The main glycosidic linkages were β-1, 4-Manp, which were substituted with acetyl groups at the O-2, O-3 and/or O-6 positions. DvP-1 was found to directly stimulate the activation of macrophages in vitro, as evidenced by inducing morphologic change, thereby promoting the production of cytokines TNF-α, IL-6 and NO, and enhancing the pinocytic activity of macrophages. By establishing a zebrafish model, we also found that DvP-1 could alleviate vinorelbine-induced decrease of macrophages in vivo. Further findings indicated that DvP-1 activated macrophages through several toll-like receptors (TLRs), but mainly through TLR4. DvP-1 served as a TLR4 agonist and induced ERK, JNK, p38, and IκB-α phosphorylation, suggesting the activation of MAPK and NFκB signaling pathways downstream of TLR4. These findings could help us further understand the immunomodulating effects of D. devonianum in Chinese medicines or health foods for immunocompromised persons. They also show the medicinal value of DvP-1 for the treatment of cancer and infectious diseases caused by TLR4 dysfunction.

Antiasthmatic Effects of Sanglong Pingchuan Decoction through Inducing a Balanced Th1/Th2 Immune Response

Objective

To investigate the antiasthmatic effects of Sanglong pingchuan decoction (SLPCD) and to explore its mechanisms of action.

Methods

The serum, bronchoalveolar lavage fluid (BALF), and lung tissues from OVA-induced allergic asthma mice were collected 24 h after the last administration. Lung pathological changes were observed by H&E staining. The inflammatory cells in BALF were counted by flow cytometry. The levels of total IgE in serum and cytokines in BALF were determined by ELISA. The expression levels of cytokine mRNA in lung were assayed by qRT-PCR.

Results

SLPCD significantly inhibited airway inflammation, reduced inflammatory cells in BALF, reduced the levels of total IgE in serum and Th2 cytokines (IL-10 and IL-13) in BALF, and downregulated the mRNA expression levels of Th2 cytokines (IL-4, IL-5, IL-10, and IL-13) in lung of asthmatic mice. However, SLPCD remarkably elevated the level of Th1 cytokine IFN-γ in BALF and upregulated the mRNA expression levels of Th1 cytokines (IL-2 and IFN-γ) in lung of asthmatic mice.

Conclusion

SLPCD could attenuate airway inflammation and alleviate the pathogenesis in asthma mice through inducing a balanced Th1/Th2 response and could act as an effective drug for treatment of asthma.

Pathway analysis of global gene expression change in dendritic cells induced by the polysaccharide from the roots of Actinidia eriantha

ETHNOPHARMACOLOGICAL RELEVANCE

The roots of Actinidia eriantha Benth have been used clinically to treat a variety of cancers in traditional Chinese medicine. The polysaccharide from this drug (AEPS) was previously reported to be a potential antitumor agent with immunomodulatory activity. However, the mechanisms of its antitumor action in immunomodulation have not yet been well-defined.

AIM OF THE STUDY

To investigate the effects of AEPS on the phenotypic and functional maturation of dendritic cells and to explore the intracellular signaling mechanisms of its antitumor action in the immunomodulation.

MATERIALS AND METHODS

The effects of AEPS on the phagocytic activity, expression of surface molecules, mRNA and protein expression levels of cytokines and chemokines in mouse bone-marrow derived dendritic cells (BMDCs) were determined by flow cytometry, qRT-PCR and ELISA, respectively. The transcriptional profile induced by AEPS was established using oligonucleotide microarray, and Ingenuity Pathway Analysis (IPA) was used to identify potential signaling pathways. Western blotting, neutralization experiments and inhibition assay were performed to confirm signaling pathway involved in maturation of DCs induced by AEPS. Furthermore, we discussed the downstream effects of the action of AEPS using clustering, network and pathway mapping approaches.

RESULTS

AEPS could significantly reduced phagocytic activity, promoted expression of accessory and co-stimulatory molecules, and up-regulated the mRNA and protein expression levels of cytokines and chemokines in BMDCs. Microarray assay revealed that AEPS induced significantly differential expression of 452 genes including up-regulated cytokines (IL-6, IL-1β, TNF-α, IL-10, IL-12p40, IFN-β and IFN-γ), chemokines (MIP-1α, MIP-1β, CCL5, MDC and MCP-1), transcription factors (STAT1, STAT2, STAT5b, IRF1 and IRF7) and pattern recognition receptors (TLR3, DDX58, DHX58 and IFIH1) in the BMDCs. AEPS-induced production of TNF-α and IL-12p40 from BMDCs was inhibited by antibodies against TLR2 and TLR4. Furthermore, AEPS induced the phosphorylation of NF-κB p65 in a time-dependent manner, and BAY 11-7082, an inhibitor of NF-κB, remarkably suppressed the production of cytokines induced by AEPS.

CONCLUSION

AEPS triggers the phenotypic and functional maturation of DCs via TLR2/4 and NF-κB signaling pathway, resulting in augmented antitumor immune responses. Our results suggested that AEPS might be helpful in potentiating the efficiency of DC-based cancer immunotherapy. This study further expanded current knowledge on the mechanisms of antitumor action of AEPS.

Cynanbungeigenin C and D, a pair of novel epimers from Cynanchum bungei, suppress hedgehog pathway-dependent medulloblastoma by blocking signaling at the level of Gli

Uncontrolled excessive activation of Hedgehog (Hh) signaling pathway is linked to a number of human malignant tumorigenesis. To obtain valuable Hh pathway inhibitors from natural product, in present study, a pair of novel epimers, Cynanbungeigenin C (CBC) and D (CBD) from the plant Cynanchum bungei Decne were chemically characterized by multiple spectroscopic data and chemical derivatization, and evaluated for their inhibition on Hh pathway. Mechanistically, CBC and CBD block Hh pathway signaling not through targeting Smo and Sufu, but at the level of Gli. In addition, both eipmers significantly suppress Hh pathway-dependent Ptch^+/-; p53^-/- medulloblastoma in vitro and in vivo. Furthermore, both CBC and CBD inhibited two Smo mutants induced Hh pathway activation, which suggested that they are potential compounds for the treatment of medulloblastoma with primary or acquired resistance to current Smo inhibitors. These results highlight the potential of CBC and CBD as effective lead compounds in the treatment of medulloblastoma and other Hh-dependent malignancy.