Accelerated and Severe Lupus Nephritis Benefits From M1, an Active Metabolite of Ginsenoside, by Regulating NLRP3 Inflammasome and T Cell Functions in Mice.

Chinese herbal medicines used in combination have long-term been shown to be mild remedies with "integrated effects." However, our study provides the first demonstration that M1, an active metabolite of ginsenoside, exerted its dramatic therapeutic effects on accelerated and severe lupus nephritis (ASLN) mice, featuring acute renal function impairment, heavy proteinuria, high serum levels of anti-dsDNA, and high-grade, diffuse proliferative renal lesions. In the present study, NZB/WF1 mice were given injections of lipopolysaccharide to induce the ASLN model. M1 (30 mg/kg) was then administered to the mice by gavage daily, and the mice were sacrificed on week 3 and week 5 after the induction of disease. To identify the potential mechanism of action for the pure compound, levels of NLRP3 inflammasome activation in bone marrow-derived dendritic cells (BMDCs), podocytes and macrophages, and antigen-specific T cell activation in BMDCs were determined in addition to mechanistic experiments in vivo. Treatment with M1 dramatically improved renal function, albuminuria and renal lesions and reduced serum levels of anti-dsDNA in the ASLN mice. These beneficial effects with M1 treatment involved the following cellular and molecular mechanistic events: [1] inhibition of NLRP3 inflammasome associated with autophagy induction, [2] modulation of T help cell activation, and [3] induction of regulatory T cell differentiation. M1 improved the ASLN mice by blunting NLRP3 inflammasome activation and differentially regulating T cell functions, and the results support M1 as a new therapeutic candidate for LN patients with a status of abrupt transformation of lower-grade (mesangial) to higher-grade (diffuse proliferative) nephritis.

A Benzenoid 4,7-Dimethoxy-5-Methyl-L, 3-Benzodioxole from Antrodia cinnamomea Attenuates Dendritic Cell-Mediated Th2 Allergic Responses.

Dendritic cells (DCs) play a critical role in initiating immune responses; however, DCs also induce Th2-related allergic sensitivities. Thus, DCs become a target for therapeutic design in allergic diseases. In this study, we aim to investigate the anti-allergic effect of pure compounds from a medicinal mushroom Antrodia cinnamomea (Ac) on DC-induced allergic responses. We identified a benzenoid compound 4,7-dimethoxy-5-methyl-l,3-benzodioxole (DMB) which may modulate Th2 polarization in bone marrow-derived DCs (BMDCs) and in a murine food allergy model. DMB effectively reduced the Th2 adjuvant cholera toxin (CT)-induced BMDC maturation and cytokine production. In studying the mechanism, DMB blocked the molecular processes involved in Th2 induction, including cAMP activation, IL-33 production, and IRF4/Tim4 upregulation, in CT-activated BMDCs. Furthermore, DMB treatment attenuated the symptoms, clinical scores, and Th2 responses of CT-induced ovalbumin (OVA)-specific food allergy in mice at sensitization stage. These results indicated that DMB could suppress DC function for Th2 polarization and mitigate allergic responses. Thus, DMB may have potential to be a novel agent for preventing or treating food allergy.

Gold lotion from citrus peel extract ameliorates imiquimod-induced psoriasis-like dermatitis in murine.

BACKGROUND: Gold lotion (GL), a natural mixed product made from the peels of six citrus fruits, has recently been identified as possessing anti-oxidative, anti-inflammatory, and immunomodulatory effects. GL has been used to protect skin against UV-induced damage, but its activity against psoriasis, a chronic autoimmune skin disease caused by dysregulation between immune cells and keratinocytes, is not known. We therefore evaluated the effect of GL on imiquimod (IMQ)-induced psoriasis-like inflammation in mice. RESULTS: GL treatment significantly attenuated IMQ-induced psoriasis-like symptoms in mice. The inflammatory cytokines upregulated by IMQ in skin lesions were also inhibited by feeding GL. In addition, GL treatment reduced the infiltration of CD4+ T cells/neutrophils in skin lesions and the percentage of IL-17-/IL-22-producing T cells in lymph nodes. Furthermore, GL impaired IMQ-induced type I interferon production by plasmacytoid dendritic cells (pDCs) in vitro. CONCLUSION: Our results indicate GL can act to suppress the initiation of psoriasis and strongly suggest that GL may have potential to be applied to the treatment of psoriasis. © 2018 Society of Chemical Industry.

Naringenin inhibits dendritic cell maturation and has therapeutic effects in a murine model of collagen-induced arthritis.

The aim of this study was to investigate the effect of naringenin (5,7,4'-trihydroxyflavanone), a citrus flavonoid, on dendritic cell (DC) maturation, as well as its potential as a therapeutic agent in a murine model of collagen-induced arthritis (CIA). Naringenin effectively inhibited lipopolysaccharide (LPS)-induced DC maturation as shown by reductions in the production of proinflammatory cytokines/chemokines, the expression of costimulatory molecules and the Ag-specific T cell priming ability of DCs when given at noncytotoxic doses. In addition, the decrease of LPS-induced MAPK and NF-κB signaling activation may contribute to the inhibitory activity of naringenin. In mice with CIA, the oral administration of naringenin ameliorated the severity of arthritis, reduced the levels of anticollagen Type II (CII) IgG and limited the proliferation of T cells, observed as a lower frequency of Th1 and Th17 cells in the spleen after restimulation with CII. In conclusion, this study shows for the first time that naringenin can manipulate the immunostimulatory properties of DCs and thus represents a potential therapeutic for the treatment of rheumatoid arthritis in humans.

Formulated extract from multiple citrus peels impairs dendritic cell functions and attenuates allergic contact hypersensitivity.

It has been reported that gold lotion (GL), a formulated product made from the peels of six citrus fruits, has many pharmacological properties, such as anti-tumor, antioxidant, and anti-inflammatory activities. In this study, we investigated the immunomodulatory effect of GL on lipopolysaccharide (LPS) stimulated mouse bone marrow-derived DC maturation and function. Our experimental results have shown that GL significantly impaired the pro-inflammatory cytokine and chemokine secretion, suppressed the expression of major histocompatibility complex class I/II and costimulatory molecules (CD40, CD80 and CD86), increased phagocytic capacity, and reduced propensity to stimulate the autologous CD4(+) and CD8(+) T cell proliferation of LPS-induced DCs. Furthermore, we found that oral administration of GL attenuated the 2,4-Dinitro-1-fluorobenzene induced contact hypersensitivity (CHS) in animal models. Subsequently, our molecular mechanism studies showed that GL interfered with LPS-induced MAPK-JNK, p38 phosphorylation and nuclear translocation of NF-κB p65. In an essence, these findings are the first report to provide new insight in the immunopharmacological role of GL in terms of its effects on DC.

Polysaccharides from Ganoderma formosanum function as a Th1 adjuvant and stimulate cytotoxic T cell response in vivo.

The fungus of Ganoderma is a basidiomycete that possesses a variety of pharmacological effects and has been used in traditional Asian medicine for centuries. Ganoderma formosanum is a native Ganoderma species isolated in Taiwan, and we have previously demonstrated that PS-F2, a polysaccharide fraction purified from the submerged culture broth of G. formosanum, exhibits immunostimulatory properties in macrophages. In this study, we further characterized the adjuvant functions of PS-F2. In vitro, PS-F2 stimulated dendritic cells (DCs) to produce proinflammatory cytokines, including TNF-α, interleukin (IL)-6, and IL-12/IL-23 p40. PS-F2 also stimulated DCs to express the maturation markers CD40, CD80, CD86, and MHC class II. In a murine splenocyte culture, PS-F2 treatment resulted in elevated expression of T-bet and interferon (IFN)-γ in T lymphocytes. When used as an adjuvant in vivo with the ovalbumin (OVA) antigen, PS-F2 stimulated OVA-specific antibody production and primed IFN-γ production in OVA-specific T lymphocytes. PS-F2-adjuvated immunization also induced OVA-specific CTLs, which protected mice from a challenge with tumor cells expressing OVA. Collectively, our data show that PS-F2 functions as an adjuvant capable of inducing a Th1-polarized adaptive immune response, which would be useful in vaccines against viruses and tumors.

Clitocybe nuda Activates Dendritic Cells and Acts as a DNA Vaccine Adjuvant.

This work represents the first evaluation of the effects of water extract of C. nuda (WE-CN), an edible mushroom, on murine bone marrow-derived dendritic cells (BMDCs) and the potential pathway through which the effects are mediated. Our experimental results show that WE-CN could induce phenotypic maturation of DCs, as shown by the increased expression of MHC and costimulatory molecules. In addition, it also induced the proinflammatory cytokines expression on DCs and enhanced both the proliferation and IFN- γ secretion of allogenic T cells. Therefore, since WE-CN did not induce maturation of DCs generated from mice with mutated TLR-4 or TLR-2, suggesting that TLR4 and TLR2 might function as membrane receptors for WE-CN. Moreover, the mechanism of action of WE-CN may be mediated by increased phosphorylation of ERK, p38, and JNK mitogen-activated protein kinase (MAPK) and increased NF- κ B p65 activity, which are important signaling molecules downstream of TLR-4 and TLR-2. Finally, coimmunization of mice with WE-CN and a HER-2/neu DNA vaccine induced a HER-2/neu-specific Th1 response that resulted in significant inhibition of HER-2/neu overexpressing mouse bladder tumor (MBT-2) growth. These data suggest that WE-CN induces DC maturation through TLR-4 and/or TLR-2 and that WE-CN can be used as an adjuvant in cancer vaccine immunotherapy.

Acetylcorynoline impairs the maturation of mouse bone marrow-derived dendritic cells via suppression of IκB kinase and mitogen-activated protein kinase activities.

BACKGROUND: Dendritic cells (DCs) are major modulators in the immune system. One active field of research is the manipulation of DCs as pharmacological targets to screen novel biological modifiers for the treatment of inflammatory and autoimmune disorders. Acetylcorynoline is the major alkaloid component derived from Corydalis bungeana herbs. We assessed the capability of acetylcorynoline to regulate lipopolysaccharide (LPS)-stimulated activation of mouse bone marrow-derived DCs. METHODOLOGY/PRINCIPAL FINDINGS: Our experimental data showed that treatment with up to 20 µM acetylcorynoline does not cause cytotoxicity in cells. Acetylcorynoline significantly inhibited the secretion of tumor necrosis factor-α, interleukin-6, and interleukin-12p70 by LPS-stimulated DCs. The expression of LPS-induced major histocompatibility complex class II, CD40, and CD86 on DCs was also decreased by acetylcorynoline, and the endocytic capacity of LPS-stimulated DCs was restored by acetylcorynoline. In addition, LPS-stimulated DC-elicited allogeneic T-cell proliferation was blocked by acetylcorynoline, and the migratory ability of LPS-stimulated DCs was reduced by acetylcorynoline. Moreover, acetylcorynoline significantly inhibits LPS-induced activation of IκB kinase and mitogen-activated protein kinase. Importantly, administration of acetylcorynoline significantly attenuates 2,4-dinitro-1-fluorobenzene-induced delayed-type hypersensitivity. CONCLUSIONS/SIGNIFICANCE: Acetylcorynoline may be one of the potent immunosuppressive agents through the blockage of DC maturation and function.

Myricetin attenuates lipopolysaccharide-stimulated activation of mouse bone marrow-derived dendritic cells through suppression of IKK/NF-κB and MAPK signalling pathways.

BACKGROUND: Myricetin is a naturally occurring flavonoid that is found in many fruits, vegetables, teas and medicinal herbs. It has been demonstrated to have anti-inflammatory properties, but, to date, no studies have described the immunomodulatory effects of myricetin on the functions of dendritic cells (DCs). The aim of this study was to evaluate the potential for myricetin to modulate lipopolysaccharide (LPS)-stimulated activation of mouse bone marrow-derived DCs. RESULTS: Our experimental data showed that treatment with myricetin up to 10 µg mL(-1) does not cause cytotoxicity in cells. Myricetin significantly decreased the secretion of tumour necrosis factor-α, interleukin-6 and interleukin-12p70 by LPS-stimulated DCs. The expression of LPS-induced major histocompatibility class II, CD40 and CD86 on DCs was also inhibited by myricetin, and the endocytic and migratory capacity of LPS-stimulated DCs was blocked by myricentin. In addition, LPS-stimulated DC-elicited allogeneic T-cell proliferation was reduced by myricetin. Moreover, our results confirmed that myricetin attenuates the responses of LPS-stimulated activation of DCs via suppression of IκB kinase/nuclear factor-κB and mitogen-activated protein kinase-dependent pathways. CONCLUSION: Myricetin has novel immunopharmacological activity, and modulation of DCs by myricetin may be an attractive strategy for the treatment of inflammatory and autoimmune disorders, and for transplantation.

Extracellular polysaccharides produced by Ganoderma formosanum stimulate macrophage activation via multiple pattern-recognition receptors.

BACKGROUND: The fungus of Ganoderma is a traditional medicine in Asia with a variety of pharmacological functions including anti-cancer activities. We have purified an extracellular heteropolysaccharide fraction, PS-F2, from the submerged mycelia culture of G. formosanum and shown that PS-F2 exhibits immunostimulatory activities. In this study, we investigated the molecular mechanisms of immunostimulation by PS-F2. RESULTS: PS-F2-stimulated TNF-α production in macrophages was significantly reduced in the presence of blocking antibodies for Dectin-1 and complement receptor 3 (CR3), laminarin, or piceatannol (a spleen tyrosine kinase inhibitor), suggesting that PS-F2 recognition by macrophages is mediated by Dectin-1 and CR3 receptors. In addition, the stimulatory effect of PS-F2 was attenuated in the bone marrow-derived macrophages from C3H/HeJ mice which lack functional Toll-like receptor 4 (TLR4). PS-F2 stimulation triggered the phosphorylation of mitogen-activated protein kinases JNK, p38, and ERK, as well as the nuclear translocation of NF-κB, which all played essential roles in activating TNF-α expression. CONCLUSIONS: Our results indicate that the extracellular polysaccharides produced by G. formosanum stimulate macrophages via the engagement of multiple pattern-recognition receptors including Dectin-1, CR3 and TLR4, resulting in the activation of Syk, JNK, p38, ERK, and NK-κB and the production of TNF-α.

Kaempferol from Semen cuscutae attenuates the immune function of dendritic cells.

Dendritic cells (DCs) are the critical leukocytes in regulating immune responses. Accordingly, DCs are the major target in the development of immunomodulators. In this study, we examined the effect of Semen cuscutae (SC), an important traditional Chinese medicine, on mouse bone marrow-derived DCs. We found that the n-butanol and methanol extracts of SC significantly suppressed LPS-stimulated DC activation. Several flavonoids were verified in the extracts using HPLC, and then kaempferol was identified as the major flavonoid in the methanol fraction of SC. Kaempferol was able to reduce cytokines and chemokines produced by LPS-stimulated DCs, and this reduction was not due to its cytotoxicity on DCs. In addition, DC maturation was impaired by kaempferol. Furthermore, kaempferol abrogated the ability of LPS-stimulated DCs to promote Ag-specific T cell activation, both in vitro and in vivo. Thus, we show for the first time that SC exhibits an immunosuppressive effect on DCs and that the active ingredient kaempferol attenuates DC function, which suggests that kaempferol has potential in the treatment of chronic inflammatory and autoimmune diseases.

A novel adjuvant Ling Zhi-8 enhances the efficacy of DNA cancer vaccine by activating dendritic cells.

DNA vaccine has been suggested to use in cancer therapy, but the efficacy remains to be improved. The immunostimulatory effect of a fungal immunomodulatory protein Ling Zhi-8 (LZ-8) isolated from Ganoderma lucidum has been reported. In this study, we tested the adjuvanticity of LZ-8 for HER-2/neu DNA vaccine against p185(neu) expressing tumor MBT-2 in mice. We found that recombinant LZ-8 stimulated mouse bone marrow-derived dendritic cells (DCs) via TLR4 and its stimulatory effect was not due to any microbe contaminant. In addition, LZ-8 enhanced the ability of DCs to induce antigen-specific T cell activation in vitro and in a subunit vaccine model in vivo. Surprisingly, LZ-8 cotreatment strongly improved the therapeutic effect of DNA vaccine against MBT-2 tumor in mice. This increase in antitumor activity was attributed to the enhancement of vaccine-induced Th1 and CTL responses. Consistent with the results from DCs, the promoting effect of LZ-8 on DNA vaccine was diminished when the MBT-2 tumor cells were grown in TLR4 mutant mice. Thus, we concluded that LZ-8 may be a promising adjuvant to enhance the efficacy of DNA vaccine by activating DCs via TLR4.