Up-regulation of IL-10 expression in dendritic cells is involved in Trichosanthin-induced immunosuppression

Trichosanthin-derived peptide Tk-PQ attenuates immune rejection in mouse tracheal allotransplant model by suppressing PI3K-Akt and inducing type II immune polarization

Obliterative bronchiolitis (OB) is one of the main complications affecting long-term survival of post-lung transplantation patients. In this study, we evaluated the efficacy of Tk-PQ (a peptide derived from trichosanthin) in alleviating OB in a mouse ectopic tracheal transplant model. We found that post-transplantation treatment of Tk-PQ significant ameliorated OB symptoms including luminal occlusion, epithelial cells loss and fibrosis in the allograft. In addition, Tk-PQ promoted immune suppressive environment by inducing Th2 polarization and increasing Treg population which in turn led to elevated levels of anti-inflammatory cytokines IL-4, IL-10, IL-33 and decreased levels of pro-inflammatory IL-1β. Mechanistically, we used transcriptome analysis of splenic T cells from allografted mice to show that Tk-PQ treatment down-regulated the PI3K-Akt signaling pathway. Indeed, the immune suppression phenotypes of Tk-PQ was recapitulated by a PI3K inhibitor LY294002. Taken together, Tk-PQ regulates post-transplantation immuno-rejection by modulating the balance of T cell response via the PI3K-Akt pathway, making it a promising peptide based immune rejection suppressant for patients receiving allotransplant.

The role of dysregulated mRNA translation machinery in cancer pathogenesis and therapeutic value of ribosome-inactivating proteins

Dysregulated protein synthesis is a hallmark of tumors. mRNA translation reprogramming contributes to tumorigenesis, which is fueled by abnormalities in ribosome formation, tRNA abundance and modification, and translation factors. Not only malignant cells but also stromal cells within tumor microenvironment can undergo transformation toward tumorigenic phenotypes during translational reprogramming. Ribosome-inactivating proteins (RIPs) have garnered interests for their ability to selectively inhibit protein synthesis and suppress tumor growth. This review summarizes the role of dysregulated translation machinery in tumor development and explores the potential of RIPs in cancer treatment.

Trichosanthin Promotes Anti-Tumor Immunity through Mediating Chemokines and Granzyme B Secretion in Hepatocellular Carcinoma

Trichosanthin (TCS) is a type I ribosome-inactivating protein extracted from the tuberous root of the plant Trichosanthes. TCS shows promising potential in clinical drug abortion, anti-tumor and immunological regulation. However, the molecular mechanisms of its anti-tumor and immune regulation properties are still not well discovered. In the present study, we investigated the anti-tumor activity of TCS in hepatocellular carcinoma (HCC), both in vitro and in vivo. Both HCC cell lines and xenograft tumor tissues showed considerable growth inhibition after they were treated with TCS. TCS provoked caspase-mediated apoptosis in HCC cells and xenograft tumor tissues. The recruitment of CD8⁺ T cells to HCC tissues and the expression of chemokines, CCL2 and CCL22, were promoted upon TCS treatment. In addition, TCS induced an upregulation of Granzyme B (GrzB), TNF-α and IFN-γ in HCC tissues, which are the major cytotoxic mediators produced by T cells. Furthermore, TCS also resulted in an increase of mannose-6-phosphate receptor (M6PR), the major receptor of GrzB, in HCC tissues. In summary, these results suggest that TCS perhaps increases T-cell immunity via promoting the secretion of chemokines and accelerating the entry of GrzB to HCC cells, which highlights the potential role of TCS in anti-tumor immunotherapy.

Cocktail of Astragalus Membranaceus and Radix Trichosanthis Suppresses Melanoma Tumor Growth and Cell Migration Through Regulation of Akt-Related Signaling Pathway

Background: Malignant melanoma has high morbidity and mortality and limited treatment options. Traditional Chinese medicine has great potential in the clinical therapy of cancer, and the theory of compatibility is one core content of Chinese medical theory. Astragalus Membranaceus and Radix Trichosanthis are clinically effective for the treatment of various cancers.

Methods: We verified the effects of AMD, RTD, and their “cocktail” on melanoma model in vitro and in vivo and the mechanism of its effect on the Akt-related signaling pathway by network pharmacology, MTT, flow cytometry, LDH, SOD, MDA assay, and Western blot.

Results: The network pharmacology analysis indicated that the PI3K-Akt pathway plays a crucial role in the treatment of malignant melanoma with these two herbs. In addition, AMD, RTD, and their “cocktail” could inhibit the proliferation of A375 cells by reducing the survival rate in a concentration-dependent manner and by regulating the cell cycle, and the compatibility of two herbs also could inhibit melanoma growth. They could, respectively, induce apoptosis and inhibit migration by affecting the expression of Bcl-2, Bax, p53, snail, E-cadherin, and N-cadherin. Furthermore, LDH activity was decreased, while SOD increased and MDA reduced. The factors of the Akt-related signaling pathway, Akt and p-Akt, were decreased.

Conclusion: This study showed that AMD, RTD, and their “cocktail” could regulate cell proliferation, apoptosis, and metastasis in A375 cells through the suppression of the Akt-related signaling pathway, and the “cocktail” groups had detoxification and additive effects. The best compatibility of the two herbs also can inhibit tumor growth and metastasis in vivo.

Immunosuppressive activity of a cycloartane triterpene glycoside from Beesia calthaefolia by inhibiting T cell proliferation

BC-1 is a cycloartane triterpene glycoside isolated from the whole plant of Beesia calthaefolia. Our recent studies proved that BC-1 inhibited proliferation of splenic lymphocyte and phagocytosis of macrophages, and inhibited the increased production of TNF-α and IL-1β. However, it lacks of study about the immunomodulatory effect of BC-1 on purified T lymphocytes. Therefore, in the present study, we evaluated the suppressive potentials of BC-1 on immune responses in vitro. BC-1 markedly suppressed anti-CD3/CD28 mAbs (mAbs) induced murine T lymphocytes proliferation, the expression levels of CD69 and CD25 of CD3⁺ T cells. BC-1 could strongly decrease ratio of CD4⁺/CD8⁺, decrease the Th1/Th2 cytokines production (IL-2, IFN-γ, IL-4, and IL-10) of CD4⁺ T-cells. In addition, we studied signal transduction pathways about T-cell activation on puried murine CD4⁺ T lymphocytes by western-blot assay. The data revealed that BC-1 could inhibit the activation of JNK, ERK and PI3K/AKT signal transduction pathways. These results indicated that BC-1 possesses potential downregulating effect on the immune system and might be developed as an immunosuppressive agent in treatment of CD4⁺ T cell-mediated inflammatory and undesired immune responses.

Genetically-engineered "all-in-one" vaccine platform for cancer immunotherapy

An essential step for cancer vaccination is to break the immunosuppression and elicit a tumor-specific immunity. A major hurdle against cancer therapeutic vaccination is the insufficient immune stimulation of the cancer vaccines and lack of a safe and efficient adjuvant for human use. We discovered a novel cancer immunostimulant, trichosanthin (TCS), that is a clinically used protein drug in China, and developed a well-adaptable protein-engineering method for making recombinant protein vaccines by fusion of an antigenic peptide, TCS, and a cell-penetrating peptide (CPP), termed an “all-in-one” vaccine, for transcutaneous cancer immunization. The TCS adjuvant effect on antigen presentation was investigated and the antitumor immunity of the vaccines was investigated using the different tumor models. The vaccines were prepared via a facile recombinant method. The vaccines induced the maturation of DCs that subsequently primed CD8⁺ T cells. The TCS-based immunostimulation was associated with the STING pathway. The general applicability of this genetic engineering strategy was demonstrated with various tumor antigens (i.e., legumain and TRP2 antigenic peptides) and tumor models (i.e., colon tumor and melanoma). These findings represent a useful protocol for developing cancer vaccines at low cost and time-saving, and demonstrates the adjuvant application of TCS—an old drug for a new application.

Peptide Tk-PQ induces immunosuppression in skin allogeneic transplantation via increasing Foxp3+ Treg and impeding nuclear translocation of NF-κB

Solid organ transplantation is used as the last resort for patients with end-stage disease, but allograft rejection is an unsolved problem. Here, we showed that Tk-PQ, a peptide derived from trichosanthin, had an immune-suppressive effect without obvious cytotoxicity in vitro and in a mouse skin allo-transplantation model. In vitro, treatment of Tk-PQ administrated type 2 T helper cell (Th2)/regulatory T-cell (Treg) cytokines, and increased the ratio of CD4⁺CD25⁺Foxp3⁺ Treg by repressing the PI3K/mTOR pathway. In addition, Tk-PQ decreased NF-κB activation to downregulate pro-inflammatory cytokines. Tk-PQ treatment in the mouse skin transplantation model also caused the similar molecular and cellular phenotypes. Furthermore, Tk-PQ enhanced the suppressive function of Treg by increasing Foxp3 expression, and substantially improved allograft survival. These finding demonstrate that Tk-PQ has the potential to be used in clinical allogeneic transplantation.

Chinese Medicine Protein and Peptide in Gene and Cell Therapy

The success of gene and cell therapy in clinic during the past two decades as well as our expanding ability to manipulate these biomaterials are leading to new therapeutic options for a wide range of inherited and acquired diseases. Combining conventional therapies with this emerging field is a promising strategy to treat those previously-thought untreatable diseases. Traditional Chinese medicine (TCM) has evolved for thousands of years in China and still plays an important role in human health. As part of the active ingredients of TCM, proteins and peptides have attracted long-term enthusiasm of researchers. More recently, they have been utilized in gene and cell therapy, resulting in promising novel strategies to treat both cancer and non-cancer diseases. This manuscript presents a critical review on this field, accompanied with perspectives on the challenges and new directions for future research in this emerging frontier.

Prolonged survival effects induced by immature dendritic cells and regulatory T cells in a rat liver transplantation model

BACKGROUND

Dendritic cells (DCs) and regulatory T (Treg) cells are crucial for inducing immune tolerance. However, the suppressive function of infused Treg cells and immature DCs (imDCs) following solid organ transplantation remains unclear.

METHODS

ImDCs derived from DA-donor rats and Treg cells isolated from spleens of Lewis rats were prepared. A heterotopic liver transplantation model was established to examine the immune tolerance effects of infusion of Treg-imDCs, imDCs and Treg cells individually. Th1/Th2 cytokines and TRAL were detected by ELISA. The overall rejection grade was assessed and the rejection activity index (RAI) was calculated. TUNEL-positive lymphocytes were detected in the portal area in liver sections.

RESULTS

The infusion of Treg-imDCs was more effective than imDCs or Treg cells individually. Moreover, the expression of IL-10 and TGF-β1 was significantly up-regulated, and IL-12 expression was significantly down-regulated, especially in the Treg-imDCs group. The percentage of TUNEL-positive cells was significantly higher in the Treg cells and imDCs groups. The RAI values in Treg-imDCs group on days 3 and 7 were lower than control, imDCs and Treg cells groups individually (p<0.05). Both TBIL and ALT levels in the Treg-imDCs and imDCs groups were significantly lower than those of the control and Treg cells groups, and serum TRAL levels increased significantly 10days after transplantation in the imDC and Treg-imDC groups compared with the control and Treg cells groups (P<0.001).

CONCLUSION

These data demonstrated that infusion of Treg cells and/or imDCs induces alloantigen tolerance and prolongs liver allograft survival. The infusion of Treg-imDCs was more effective than imDCs or Treg cells individually. ImDCs synergize with Treg cells in inducing and maintaining the feedback loop between imDCs and Treg cells in vivo.

The immunoregulatory effects of Chinese herbal medicine on the maturation and function of dendritic cells

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese herbal medicine (CHM) has a long-history for treatment of various human diseases including tumors, infection, autoimmune diseases in Asian countries, especially in China, Japan, Korea and India. CHM was traditionally used as water extracts and many Chinese herbs were considered to be good for health, which can regulate immune system to protect host from diseases. With the progress of technology, the components of CHM were identified and purified, which included polysaccharides, saponins, phenolic compounds, flavonoids and so on. Recently, accumulating evidence indicates that CHM and its components can regulate immune system through targeting dendritic cells (DCs). We hereby reviewed the immunoregulatory effects of CHM on the maturation, cytokine production and function of DCs. This should help to shed light on the potential mechanism of CHM to improve the usage and clinical efficacy of CHM.

MATERIALS AND METHODS

Literatures about the effects of CHM on DCs were searched in electronic databases such as Pubmed, Google Scholar and Scopus from 2000 to 2014. 'CHM', 'DC' or 'immune' were used as keywords for the searches. We only reviewed literatures published in English.

RESULTS

Over 600 publications were found about 'CHM&immune' and around 120 literatures about 'CHM&DC' were selected and reviewed in this paper. All publications are backed by preclinical or clinical evidences both in vitro and in vivo. Some CHM and its components promote the maturation, pro-inflammatory cytokine production and function of DCs and as the adjuvant enhance immune responses against tumor and infection. In contrast, other CHM and its components suppress the activation status of DCs to induce regulatory T cells, inhibit allergic and inflammatory responses, ameliorate autoimmune diseases, and prolong the allograft survival. A large body of evidence shows that CHM and its components regulate the activation status of DCs through TLRs, NF-κB, MAPK signaling pathways.

CONCLUSION

This review provides useful information for understanding the mechanism of CHM on the treatment of diseases, which facilitates to improve the efficacy of CHM. Based on the immunoregulatory effects of CHM on DCs, it indicated that some CHM and its components could be use to develop adjuvant to enhance antigen-specific immune responses or tolerogenic adjuvant to generate antigen-specific immune tolerance.

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.

A Trichosanthin-derived peptide suppresses type 1 immune responses by TLR2-dependent activation of CD8(+)CD28(-) Tregs

A group of 15-aa-long Trichosanthin-derived peptides was synthesized and screened based on their differential abilities to induce low-responsiveness in mouse strains with high and low susceptibility. One of them was conjugated to form a homo-tetramer Tk-tPN. At concentrations of 0.1-50 μg/ml, Tk-tPN activated CD8(+)CD28(-) Tregs in vitro to induce immune suppression as effectively as the native Trichosanthin but did not exhibit cytotoxicity. In EAE mice which were pre-treated with Tk-tPN or Tk-tPN-activated CD8(+) T cells, a marked attenuation of clinical scores was recorded together with an expansion of the CD8(+)CD28(-) Treg from 2.2% to 36.1% in vivo. A pull-down assay and signal transduction analyses indicated that the ability of Tk-tPN to convert the CD8(+)CD28(-) Treg-related cytokine secretion pattern from type 1 to type 2 depends on the TLR2-initiated signaling in macrophages. The high production of IL-4/IL-10 by the Tk-tPN-activated CD8(+)CD28(-) Treg suggests the value of using Tk-tPN as a therapeutic reagent for Th1-dominant immunological diseases.

Functional study of immature dendritic cells co-transfected with IL-10 and TGF-beta 1 genes in vitro

Dendritic cells (DC) have important functions in T cell immunity and T cell tolerance. Previous studies suggest that immature dendritic cells (imDCs) might be involved in the induction of peripheral T cell tolerance. While interleukin-10 (IL-10) functions at different levels of the immune response, transforming growth factor-beta 1 (TGF-beta 1) is considered to be a key factor in immune tolerance. In this study, we investigated the effects of immature DC (imDC) co-transfected with IL-10 and TGF-beta 1 genes (IL-10-TGF-beta 1-imDC) on inducing immune tolerance. Moreover, we compared the effects of IL-10-TGF-beta 1-imDC with IL-10 transfected imDC (IL-10-imDC) and TGF-beta 1-transfected imDC (TGF-beta 1-imDC), respectively. IL-10-TGF-beta 1-imDC resulted in the down-regulation of MHC class II, CD80 and CD86. IL-10-TGF-beta 1-imDC could induce T cell hyporesponsiveness, and was reluctant to proliferate. IL-10-TGF-beta 1-imDC was more effective than IL-10-imDC and TGF-beta 1-imDC, respectively. In summary, co-expression of IL-10 and TGF-beta 1 affected the immunity of imDCs and enhanced their tolerogenicity. It might be a promising therapy for donor-specific tolerance after organ transplantation.

Clinical Outcomes of Traditional Chinese Medicine Compound Formula in Treating Sleep-Disordered Breathing Patients

Sleep-Disordered Breathing (SDB) is a prevalent affliction, which can range from simple snoring to severely obstructive sleep apnea. Compared to current treatment options of SDB, traditional Chinese medicine (TCM) provides a noninvasive way to relieve SDB-related symptoms and deaths. The purpose of this retrospective study was to observe the progression of adult SDB patients who had taken compound formula SZ + NUH (concentrated herbal granules) for four weeks. Depending on subjects’ individual needs, minor additions of formulas or single herbs were allowed. We found a significant amount of relief from snoring among the 118 enrolled subjects, according to before-after scores observed through the Snore Outcome Survey (SOS). Furthermore, as projected from the moderate linear correlation in before-after scores, we inferred that those cases with more severe snoring at baseline had greater improvement after treatment. Excessive daytime sleepiness was also significantly improved according to the results of the Epworth Sleepiness Scale (ESS). Assessment, using the SF-36 (Taiwanese version) revealed possible benefits of SZ + NUH in improving multiple facets of subjects’ quality of life. During treatment, no significant side effects occurred. In conclusion, the TCM compound formula based on SZ + NUH could be a safe and effective option for SDB treatment.

A role for trichosanthin in the expansion of CD4CD25 regulatory T cells

CD4(+)CD25(+) regulatory T cells (Tregs) are critical for the peripheral immune tolerance. Understanding the signals for the generation of Tregs is important for the clinical immunotherapy, but only limited progress has been made on obtaining enough peripheral Tregs. The aim of this study was to evaluate the role of trichosanthin (Tk) extracted from Chinese medicinal herb Trichosanthes kirilowi on the function of Tregs in vitro and in vivo. We reported here that Tk is needed for the expansion of freshly isolated CD4(+)CD25(+)Tregs (nTregs) into Tk-expanded CD4(+)CD25(+)Tregs (Tk-Tregs) through up-regulating CD25 and Foxp3 expression. The dose-response analyses indicated that 100 ng/ml Tk was the most appropriate dose. The result of real-time PCR showed that Tk-Tregs expressed 1.5-fold higher levels of Foxp3 than those observed in nTregs. Tk-Tregs markedly suppressed activation of effector T cells at a suppressor/responder ratio of 1:1, 1:2, 1:4, 1:8 or 1:16, and their effect was dose dependent. Moreover, Tk-Tregs secreted more immunosuppressive cytokines interleukin (IL)-10 and transforming growth factor (TGF)-beta1 after stimulating with antigen and antigen-presenting cells (APC). Transwell experiments showed that not only cell-to-cell contact but also soluble cytokines were involved in suppressive mechanism of Tk-Tregs. And Tk-Tregs were more efficient in suppressing CD25(-)T cell response to specific antigen than to irrelative antigen. Most importantly, it was revealed for the first time that Tk-Tregs could prolong the survival duration of mice with acute graft-versus-host disease (aGVHD). In conclusion, the study suggests a possible therapeutic potential of Tk-Tregs for clinical treatment on aGVHD.

Trichosanthin, an extract of Trichosanthes kirilowii, effectively prevents acute rejection of major histocompatibility complex-mismatched mouse skin allograft

Trichosanthin is an active component extracted from the root tuber of the Chinese medicinal herb Trichosanthes kirilowii. Trichosanthin has abortifacient, anti-tumor, anti-HIV, and immunoregulatory functions. In the current study, we explored its potential effect on allograft rejection in a murine skin transplantation model across a fully mismatched major histocompatibility complex. It was found that treatment of recipient mice with trichosanthin (0.25 or 1 mg/kg, IP) significantly delayed allograft rejection. T cells that originated from recipients treated with trichosanthin were restimulated with donor-specific splenocytes showed a significantly reduced response compared with that of control recipients. In line with these results, the mRNA levels for interleukin (IL)-2 and interferon-gamma were decreased and the levels of IL-4 and IL-10 were increased in splenic T cells originating from trichosanthin-treated recipients. These results indicated that trichosanthin may have potential therapeutic value for transplantation rejection and other inflammatory diseases.