Periplocoside E inhibits experimental allergic encephalomyelitis by suppressing interleukin 12-dependent CCR5 expression and interferon-gamma-dependent CXCR3 expression in T lymphocytes

Neuroprotective effects of crude extracts, compounds, and isolated molecules obtained from plants in the central nervous system injuries: a systematic review

The number of people with central nervous system (CNS) injuries increases worldwide and only a few therapies are used to mitigate neurological damage. Crude extracts, compounds, and isolated molecules obtained from plants have neuroprotective effects; however, their actions on the central nervous system are still not fully understood. This systematic review investigated the neuroprotective effects of crude extracts, compound, and isolated molecules obtained from plants in different CNS lesions. This PICO (Population/Problem, Intervention, Control, Outcome) systematic review included in vivo and in vitro studies that used small rodents as experimental models of CNS injuries (P) treated with crude extracts, compounds, and/or isolated molecules obtained from plants (I), compared to non-intervention conditions (C), and that showed a neuroprotective effect (O). Fourteen out of 5,521 studies were selected for qualitative analysis. Several neuroprotective effects (improvement of antioxidant activity, modulation of the inflammatory response, tissue preservation, motor and cognitive recovery) in the brain and spinal cord were reported after treatment with different doses of crude extracts (10 studies), compounds (2 studies), and isolated molecules (2 studies). Crude extracts, compounds, or isolated molecules obtained from plants showed promising neuroprotective effects against several CNS injuries in both the brain and spinal cord, regardless of gender and age, through the modulation of inflammatory activity and oxidative biochemistry, tissue preservation, and recovery of motor and cognitive activity.

Anti-nociceptive, anti-inflammatory and anti-arthritic activities of pregnane glycosides from the root bark of Periploca sepium Bunge

ETHNOPHARMACOLOGICAL RELEVANCE

Periploca sepium Bunge (P. sepium) is used in traditional Chinese medicine (TCM) for the treatment of autoimmune diseases, particularly rheumatoid arthritis. Periploca sepium periplosides (PePs), isolated from the root bark of P. sepium, characterized as the cardiac glycosides-free pregnane glycosides fraction, is expected to possess therapeutic potential on inflammatory arthritis.

AIM OF THE STUDY

The current study is designed to evaluate the anti-nociceptive, anti-inflammatory and anti-arthritic activities effects of the PePs.

MATERIALS AND METHODS

The anti-nociceptive activity of PePs was examined in the writhing test and hot-plate test in mice. The anti-inflammatory activity of PePs was determined by the 2, 4-dinitro-1-fluorobenzene (DNFB)-induced ear edema model and the carrageenan induced paw edema model in mice. The anti-arthritic activity of PePs was investigated by evaluating the joint inflammation and arthritis pathology in rat adjuvant induced arthritis (AIA) and murine collagen induced arthritis (CIA). Phytohaemagglutinin M (PHA-M) -elicited human peripheral blood mononuclear cells (PBMCs) were further applied to assess the suppressive activity of PePs on IFN-γ and IL-17 production.

RESULTS

PePs treatment markedly decreased the acetic acid-induced visceral nociceptive response and increased the hot-plate pain threshold. Further, oral administration of PePs exhibited anti-inflammatory activity by decreasing DNFB-induced ear edema in mice and carrageenan-induced paw edema in rats. Moreover, oral treatment of PePs ameliorated joint swelling and attenuated bone erosion in rodent arthritis, and the therapeutic benefits were partially attributed to the suppression of proinflammatory cytokines such IFN-γ and IL-17. Moreover, PePs suppressed the proliferation as well as IFN-γ and IL-17 secretion in PHA-M-elicited human PBMCs in a concentration dependent manner.

CONCLUSIONS

Taken together, our results justified the traditional use of Periploca sepium Bunge for the treatment of diseases associated with inflammation and pain.

Minor immunosuppressive spiroorthoester group-containing pregnane glycosides from the root barks of Periploca sepium

LC-MS guided chemical investigation of the periploside-rich extract of the root barks of Periploca sepium afforded six new minor pregnane glycosides, named periplosides A1-A6 (1-6). Their structures were characterized on the basis of extensive spectroscopic analysis. Compounds 1-6 were evaluated for their inhibitory activities against the proliferation of T and B lymphocytes in vitro, among them, compound 5 exhibited significant inhibitory activities and the most favorite selective index (SI) values against the proliferation of T lymphocyte (IC₅₀ = 0.30 μM, SI = 176) and B lymphocyte (IC₅₀ = 0.55 μM, SI = 97).

Ethanol and Cytokines in the Central Nervous System

The innate immune system plays a critical role in the ethanol-induced neuroimmune response in the brain. Ethanol initiates the innate immune response via activation of the innate immune receptors Toll-like receptors (TLRs, e.g., TLR4, TLR3, TLR7) and NOD-like receptors (inflammasome NLRs) leading to a release of a plethora of chemokines and cytokines and development of the innate immune response. Cytokines and chemokines can have pro- or anti-inflammatory properties through which they regulate the immune response. In this chapter, we will focus on key cytokines (e.g., IL-1, IL-6, TNF-α) and chemokines (e.g., MCP-1/CCL2) that mediate the ethanol-induced neuroimmune responses. In this regard, we will use IL-1β, as an example cytokine, to discuss the neuromodulatory properties of cytokines on cellular properties and synaptic transmission. We will discuss their involvement through a set of evidence: (1) changes in gene and protein expression following ethanol exposure, (2) association of gene polymorphisms (humans) and alterations in gene expression (animal models) with increased alcohol intake, and (3) modulation of alcohol-related behaviors by transgenic or pharmacological manipulations of chemokine and cytokine systems. Over the last years, our understanding of the molecular mechanisms mediating cytokine- and chemokine-dependent regulation of immune responses has advanced tremendously, and we review evidence pointing to cytokines and chemokines serving as neuromodulators and regulators of neurotransmission.

Absolute Configuration of Periplosides C and F and Isolation of Minor Spiro-orthoester Group-Containing Pregnane-type Steroidal Glycosides from Periploca sepium and Their T-Lymphocyte Proliferation Inhibitory Activities

Further phytochemical investigation of the root bark of Periploca sepium afforded nine new spiro-orthoester group-containing pregnane-type glycosides termed periplosides O-V and 3-O-formyl-periploside A. The structures of these glycosides along with the absolute configuration of the unique seven-membered formyl acetal-bridged spiro-orthoester function and the 4,6-dideoxy-3-O-methyl-Δ³-2-hexosulosyl moiety were elucidated on the basis of spectroscopic data interpretation and chemical transformation. The absolute configurations of the major compounds periplosides C and F were established by single-crystal X-ray diffraction analysis. The isolated compounds were evaluated for their inhibitory activities against the proliferation of T-lymphocytes. As a result, periploside C, the most abundant glycoside containing a spiro-orthoester moiety found in the plant, exhibited the most favorite selective index value (SI = 82.5). The length and constitution of the saccharide chain in the periplosides were found to influence the inhibitory activity and the SI value.

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

Stephanthraniline A (STA), a C21 steroid isolated from Stephanotis mucronata (Blanco) Merr., was previously shown to inhibit T cells activation and proliferation in vitro and in vivo. The purpose of this study was to further evaluate the in vivo immunosuppressive activity of STA and to elucidate its potential mechanisms. The results showed that pretreatment with STA significantly attenuated concanavalin A (Con A)-induced hepatitis and reduced CD4(+) T cells activation and aggregation in hepatic tissue in mice. STA directly suppressed the activation and proliferation of Con A-induced CD4(+) T cells, and inhibited NFAT, NFκB and MAPK signaling cascades in activated CD4(+) T cells in vitro. Moreover, it was proved that STA inhibited T cells activation and proliferation through proximal T cell-receptor (TCR) signaling- and Ca(2+) signaling-independent way. The molecular docking studies predicted that STA could tight bind to PKCθ via five hydrogen. The further findings indicated STA directly inhibited PKCθ kinase activity, and its phosphorylation in activated CD4(+) T cells in vitro. Collectively, the present study indicated that STA could protect against CD4(+) T cell-mediated immunological hepatitis in mice through PKCθ and its downstream NFAT, NFκB and MAPK signaling cascades. These results highlight the potential of STA as an effective leading compound for use in the treatment of CD4(+) T cell-mediated inflammatory and autoimmune diseases.

Total synthesis of periploside A, a unique pregnane hexasaccharide with potent immunosuppressive effects

Periploside A is a pregnane hexasaccharide identified from the Chinese medicinal plant Periploca sepium, which features a unique seven-membered formyl acetal bridged orthoester (FABO) motif and potent immunosuppressive activities. Here, we show the synthesis of this molecule in a total of 76 steps with the longest linear sequence of 29 steps and 9.2% overall yield. The FABO motif is constructed via a combination of Sinaÿ's and Crich's protocol for the formation of orthoester and acetal glycosides, respectively. The 2-deoxy-β-glycosidic linkages are assembled stereoselectively with judicious choice of the glycosylation methods. The epimer at the spiro-quaternary carbon in the FABO motif has also been elaborated in a stereo-controlled manner. This epimer, as well as the synthetic analogues bearing the FABO motif, retain largely the inhibitory activities of periploside A against the proliferation of T-lymphocyte, indicating the importance of the chemical connection of the FABO motif to their immunosuppressive activity.

VBP15, a novel anti-inflammatory, is effective at reducing the severity of murine experimental autoimmune encephalomyelitis

Multiple sclerosis is a chronic disease of the central nervous system characterized by an autoimmune inflammatory reaction that leads to axonal demyelination and tissue damage. Glucocorticoids, such as prednisolone, are effective in the treatment of multiple sclerosis in large part due to their ability to inhibit pro-inflammatory pathways (e.g., NFκB). However, despite their effectiveness, long-term treatment is limited by adverse side effects. VBP15 is a recently described compound synthesized based on the lazeroid steroidal backbone that shows activity in acute and chronic inflammatory conditions, yet displays a much-reduced side effect profile compared to traditional glucocorticoids. The purpose of this study was to determine the effectiveness of VBP15 in inhibiting inflammation and disease progression in experimental autoimmune encephalomyelitis (EAE), a widely used mouse model of multiple sclerosis. Our data show that VBP15 is effective at reducing both disease onset and severity. In parallel studies, we observed that VBP15 was able to inhibit the production of NFκB-regulated pro-inflammatory transcripts in human macrophages. Furthermore, treatment with prednisolone-but not VBP15-increased expression of genes associated with bone loss and muscle atrophy, suggesting lack of side effects of VBP15. These findings suggest that VBP15 may represent a potentially safer alternative to traditional glucocorticoids in the treatment of multiple sclerosis and other inflammatory diseases.

'Neuroinflammation' differs categorically from inflammation: transcriptomes of Alzheimer's disease, Parkinson's disease, schizophrenia and inflammatory diseases compared

'Neuroinflammation' has become a widely applied term in the basic and clinical neurosciences but there is no generally accepted neuropathological tissue correlate. Inflammation, which is characterized by the presence of perivascular infiltrates of cells of the adaptive immune system, is indeed seen in the central nervous system (CNS) under certain conditions. Authors who refer to microglial activation as neuroinflammation confuse this issue because autoimmune neuroinflammation serves as a synonym for multiple sclerosis, the prototypical inflammatory disease of the CNS. We have asked the question whether a data-driven, unbiased in silico approach may help to clarify the nomenclatorial confusion. Specifically, we have examined whether unsupervised analysis of microarray data obtained from human cerebral cortex of Alzheimer's, Parkinson's and schizophrenia patients would reveal a degree of relatedness between these diseases and recognized inflammatory conditions including multiple sclerosis. Our results using two different data analysis methods provide strong evidence against this hypothesis demonstrating that very different sets of genes are involved. Consequently, the designations inflammation and neuroinflammation are not interchangeable. They represent different categories not only at the histophenotypic but also at the transcriptomic level. Therefore, non-autoimmune neuroinflammation remains a term in need of definition.

A mushroom extract Piwep from Phellinus igniarius ameliorates experimental autoimmune encephalomyelitis by inhibiting immune cell infiltration in the spinal cord

The present study aimed to evaluate the therapeutic potential of a mushroom extract from Phellinus igniarius in an animal model of multiple sclerosis. The medicinal mushroom, Phellinus igniarius, contains biologically active compounds that modulate the human immune system. Experimental autoimmune encephalomyelitis (EAE) was induced by immunization with myelin oligodendrocyte glycoprotein (MOG 35-55) in C57BL/6 female mice. A water-ethanol extract of Phellinus igniarius (Piwep) was delivered intraperitoneally every other day for the entire experimental course. Three weeks after the initial immunization, demyelination and immune cell infiltration in the spinal cord were examined. Piwep injection profoundly decreased the daily incidence rate and clinical score of EAE. The Piwep-mediated inhibition of the clinical course of EAE was accompanied by suppression of demyelination and infiltration of encephalitogenic immune cells including CD4+ T cells, CD8+ T cells, macrophages, and B cells in the spinal cord. Piwep reduced expression of vascular cell adhesion molecule-1 (VCAM-1) in the spinal cord and integrin-α 4 in the lymph node of EAE mice. Piwep also inhibited proliferation of lymphocytes and secretion of interferon-γ in the lymph node of EAE mice. The results suggest that a mushroom extract, Piwep, may have a high therapeutic potential for ameliorating multiple sclerosis progression.

Immunomodulation by transplanted human embryonic stem cell-derived oligodendroglial progenitors in experimental autoimmune encephalomyelitis

Transplantation of embryonic stem cells and their neural derivatives can lead to amelioration of the disease symptoms of experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis (MS). Oligodendroglial progenitors (OPs), derived from human embryonic stem cells (hESC, HES-1), were labeled with superparamagnetic iron oxide and transduced with luciferase. At 7 days following induction of EAE in C57/BL6 mice, 1 × 10(6) cells were transplanted in the ventricles of C57/BL6 mice and noninvasively monitored by magnetic resonance and bioluminescence imaging. Cells were found to remain within the cerebroventricular system and did not survive for more than 10 days. However, EAE mice that received hESC-OPs showed a significant improvement in neurological disability scores (0.9 ± 0.2; n = 12) compared to that of control animals (3.3 ± 0.4; n = 12) at day 15 post-transplantation. Histopathologically, transplanted hESC-OPs generated TREM2-positive CD45 cells, increased TIMP-1 expression, confined inflammatory cells within the subarachnoid space, and gave rise to higher numbers of Foxp3-positive regulatory T cells in the spinal cord and spleen. Our results suggest that transplantation of hESC-OPs can alter the pathogenesis of EAE through immunomodulation, potentially providing new avenues for stem cell-based treatment of MS.

Structural revision of periplocosides and periperoxides, natural immunosuppressive agents from the genus Periploca

The structures of a series of peroxy function containing pregnane glycosides isolated from Periploca sepium and Periploca forrestii were revised to be orthoester group bearing ones using 2D NMR spectroscopic techniques, as well as chemical transformations and X-ray crystallographic diffraction analysis. The orthoester function appears to be an essential structural feature for immunosuppressive activity.

Periplocoside A prevents experimental autoimmune encephalomyelitis by suppressing IL-17 production and inhibits differentiation of Th17 cells

AIM

The aim of this study was to determine the therapeutic effect of Periplocoside A (PSA), a natural product isolated from the traditional Chinese herbal medicine Periploca sepium Bge, in MOG(35-55) (myelin oligodendrocyte glycoprotein 35-55)-induced experimental autoimmune encephalomyelitis (EAE).

METHODS

Female C57BL/6 mice immunized with MOG(35-55) were treated with (50 mg/kg or 25 mg/kg) or without PSA following immunization and continuously throughout the study. The degree of CNS inflammation was evaluated by H&E staining. Anti-MOG-specific recall responses were analyzed by [3H]-Thymidine incorporation, ELISA, and RT-PCR. The proportion of IL-17-producing T cells was measured by flow cytometry.

RESULTS

Oral administration of PSA significantly reduced the incidence and severity of EAE, which closely paralleled the inhibition of MOG(35-55)-specific IL-17 production. Importantly, PSA inhibited the transcription of IL-17 mRNA and RORgammat. Further studies examining intracellular staining and adoptive transfer EAE validated the direct suppressive effect of PSA on Th17 cells. In vitro studies also showed that PSA significantly inhibited the differentiation of Th17 cells from murine purified CD4+ T cells in a dose-dependent manner.

CONCLUSION

PSA ameliorated EAE by suppressing IL-17 production and inhibited the differentiation of Th17 cells in vitro. Our results provide new insight into the potential mechanisms underlying the immunosuppressive and anti-inflammatory effects of PSA.

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.

Periplocoside A, a pregnane glycoside from Periploca sepium Bge, prevents concanavalin A-induced mice hepatitis through inhibiting NKT-derived inflammatory cytokine productions

Periploca sepium Bge, a traditional Chinese herb medicine, is widely used for treating rheumatoid arthritis in china. Periplocoside A (PSA), a pregnane glycoside, is a new nature product compound isolated from P. sepium Bge. We examined the protective effects of PSA, on concanavaline A (ConA)-induced hepatitis. Pretreatment with PSA dramatically ameliorated ConA-induced liver injury, which was characterized by reducing serum alanine transaminase (ALT), pathogenic cytokines of interleukin (IL)-4 and interferon (IFN)-gamma levels, impeding the liver necrosis, and thus elevating the survival rate. In vitro, PSA inhibited IL-4 and IFN-gamma productions of alpha-galactosylceramide (alpha-GalCer) or anti-CD3-activated Natural killer T (NKT) cells. Enzyme Linked Immunosorbent Assay (ELISA) and Reverse Transcription Polymerase Chain Reaction (RT-PCR) assays revealed PSA suppressed IL-4 transcription and IFN-gamma translation. In conclusion, PSA had significantly preventative effect on ConA-induced hepatitis, which was closely associated with inhibition of NKT-derived inflammatory cytokine productions. These findings suggested that PSA has the therapeutic potential for treatment of human autoimmune-related hepatitis.

CXCR3 signaling reduces the severity of experimental autoimmune encephalomyelitis by controlling the parenchymal distribution of effector and regulatory T cells in the central nervous system

The chemokine receptor CXCR3 promotes the trafficking of activated T and NK cells in response to three ligands, CXCL9, CXCL10, and CXCL11. Although these chemokines are produced in the CNS in multiple sclerosis and experimental autoimmune encephalomyelitis (EAE), their role in the pathogenesis of CNS autoimmunity is unresolved. We examined the function of CXCR3 signaling in EAE using mice that were deficient for CXCR3 (CXCR3(-/-)). The time to onset and peak disease severity were similar for CXCR3(-/-) and wild-type (WT) animals; however, CXCR3(-/-) mice had more severe chronic disease with increased demyelination and axonal damage. The inflammatory lesions in WT mice consisted of well-demarcated perivascular mononuclear cell infiltrates, mainly in the spinal cord and cerebellum. In CXCR3(-/-) mice, these lesions were more widespread throughout the CNS and were diffused and poorly organized, with T cells and highly activated microglia/macrophages scattered throughout the white matter. Although the number of CD4(+) and CD8(+) T cells infiltrating the CNS were similar in CXCR3(-/-) and WT mice, Foxp3(+) regulatory T cells were significantly reduced in number and dispersed in CXCR3(-/-) mice. The expression of various chemokine and cytokine genes in the CNS was similar in CXCR3(-/-) and WT mice. The genes for the CXCR3 ligands were expressed predominantly in and/or immediately surrounding the mononuclear cell infiltrates. We conclude that in EAE, CXCR3 signaling constrains T cells to the perivascular space in the CNS and augments regulatory T cell recruitment and effector T cell interaction, thus limiting autoimmune-mediated tissue damage.

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.