Design and SAR of Withangulatin A Analogues that Act as Covalent TrxR Inhibitors through the Michael Addition Reaction Showing Potential in Cancer Treatment.

The thioredoxin system plays an important role in cancer cells. Inhibiting thioredoxin reductase (TrxR) has emerged as an effective strategy to selectively target cancer cells. Withangulatin A (WA), a natural product extracted from the whole herb of Physalis angulata L. (Solanaceae), exhibits potent anticancer activity and other diverse pharmacological activities. To improve activity and targeting, we designed and prepared 41 semisynthetic analogues of WA. Biological evaluation indicated that the most promising compound 13a displayed the most significant effect on HT-29 cells (human colon cancer cells) (IC50 = 0.08 µM). A structure-activity relationship study indicated that α,ß-unsaturated ketones and ester are necessary groups, allowing 13a to undergo Michael addition reactions with mercaptan and selenol. Liquid chromatography-mass spectrometry (LC-MS) analysis confirmed that 13a modified selenocysteine 498 (U) residues in the redox centers of TrxR, resulting in enzyme inhibition. Therefore, compound 13a acts as a novel TrxR inhibitor and may be a promising candidate for cancer intervention.

Periplocoside A ameliorated type II collagen-induced arthritis in mice via regulation of the balance of Th17/Treg cells.

Periplocoside A (PSA) has been extracted from the Chinese herbal medicine Periploca sepium Bge to treat rheumatoid arthritis (RA) via immune regulation. We previously found that PSA exhibits immunosuppressive activity both in vitro and in vivo. Balanced regulation of helper T 17 (Th17)/regulatory T (Treg) cells is the current therapeutic direction for the treatment of RA. The present study investigated the mechanism of PSA in treating collagen-induced arthritis (CIA). The therapeutic effects and potential pharmacological mechanisms of PSA were specifically clarified by examining its effects on CIA in DBA/1 mice. PSA administration significantly relieved the severity of the arthritis, and preventive administration of PSA reduced the incidence of arthritis in the mice with CIA and relieved joint damage in terms of morphology. PSA was also able to reduce the levels of anti-collagen II (CII) antibodies and pro-inflammatory cytokines in the serum. As a result, the proportion of Th17 cells decreased, and the proportion of Treg cells increased. A follow-up study of the ex vivo immunological reactions induced by a specific antigen found that PSA suppressed lymphocyte proliferation, inhibited the differentiation and reactivity of Th17 cells, and promoted the proportion of Treg cells among helper T cells. PSA also exhibited pharmacological effect in regulating the balance between Th17 and Treg cells in CIA through relevant signalling pathways. Thus, PSA played a specific role in CIA treatment. In particular, our results suggest that the therapeutic effects of PSA on RA are partially realized via the regulation of the balance of Th17/Treg cells.

Amelioration of systemic lupus erythematosus by Withangulatin A in MRL/lpr mice.

We have previously reported the anti-inflammatory potential and the possible underlying mechanisms of Withangulatin A (WA), which is an active component isolated from Physalis angulata L. Here, we demonstrated that WA might improve the life quality, as well as reduced the accumulation of proteinuria symptoms and levels of anti-double-stranded DNA antibodies in MRL/lpr mice. Moreover, WA could improve renal histopathologic characteristics of MRL/lpr mice. Intriguingly, expression of B cell-activating factor (BAFF), BAFF-R and related gene in the spleen were significantly reduced in 10 mg/kg WA-treated mice compared with that in 5 mg/kg WA-treated mice and untreated mice. These findings indicate that WA might have a pleiotropic therapeutic effect through their immunosuppression via inhibiting BAFF signaling, which suggest a potential application of this active constituent in the treatment of SLE.

Novel guggulsterone derivative GG-52 inhibits NF-kappaB signaling in intestinal epithelial cells and attenuates acute murine colitis.

We already showed that the plant sterol guggulsterone has been reported to inhibit nuclear factor-kappaB (NF-kappaB) signaling in intestinal epithelial cells (IECs) and to attenuate dextran sulfate sodium (DSS)-induced colitis. This study investigates the anti-inflammatory effects of novel guggulsterone derivatives on IEC and preventive and therapeutic murine models of DSS-induced colitis. Novel guggulsterone derivates with high lipophilicity were designed and four derivates, including GG-46, GG-50B, GG-52, and GG-53, were synthesized. Two guggulsterone derivatives, GG-50B and GG-52, significantly inhibited the activated NF-kappaB signals and the upregulated expression of interleukin-8 (IL-8) in COLO 205 cells stimulated with tumor necrosis factor-alpha (TNF-alpha). Pretreatment with GG-50B and GG-52 attenuated the increased IkappaB kinase (IKK) and IkappaBalpha phsophorylation induced by TNF-alpha. In preventive and therapeutic models of murine colitis, administration of GG-52 significantly reduced the severity of DSS-induced colitis, as assessed by disease activity index, colon length, and histology. In contrast, GG-50B did not show a significant reduction in the colitis severity. Moreover, the efficacy on attenuating colitis by GG-52 was comparable to that by sulfasalazine or prednisolone. These results indicate that the novel guggulsterone derivative GG-52 blocks NF-kappaB activation in IEC and ameliorates DSS-induced acute murine colitis, which suggests that GG-52 is a potential therapeutic agent for the treatment of inflammatory bowel diseases.

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.

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

Periplocoside E (PSE) was found to inhibit primary T-cell activation in our previous study. Now we examined the effect and mechanisms of PSE on the central nervous system (CNS) demyelination in experimental allergic encephalomyelitis (EAE). C57BL/6 mice immunized with myelin oligodendrocyte glyco-protein (MOG) were treated with PSE following immunization and continued throughout the study. The effect on the progression of EAE and other relevant parameters were assessed. PSE reduced the incidence and severity of EAE. Spinal cord histopathology analysis showed that the therapeutic effect of PSE was associated with reduced mononuclear cell infiltration and CNS inflammation. As reverse transcription-polymerase chain reaction analysis showed, PSE decreased the CD4(+), CD8(+), and CD11b(+) cell infiltration. T cells from lymph nodes of MOG-immunized mice expressed enhanced levels of CCR5 and CXCR3 mRNA compared with T cells from normal mice. However, CCR5 and CXCR3 expressions were suppressed in T cells from PSE-treated mice. In vitro study also showed PSE inhibited interferon (IFN)-gamma-dependent CXCR3 expression in T cells through suppressing T-cell receptor (TCR) ligation-induced IFN-gamma production, whereas it inhibited interleukin (IL)-12-dependent CCR5 expression through suppressing IL-12 reactivity in TCR-triggered T cells. As a result, the initial influx of T cells into CNS was inhibited in PSE-treated mice. The consequent activation of macrophages/microglia cells was inhibited in spinal cord from PSE-treated mice as determination of chemokine expressions (CCL2, CCL3, CCL4, CCL5, CXCL9, and CXCL10). Consistently, the secondary influx of CD4(+), CD8(+), and CD11b(+) cells was decreased in spinal cords from PSE-treated mice. These findings suggest the potential therapeutic effect of PSE on multiple sclerosis.

Periplocoside E, an effective compound from Periploca sepium Bge, inhibited T cell activation in vitro and in vivo.

Periploca sepium Bge, a traditional Chinese herb medicine, is used for treating rheumatoid arthritis in China. Followed the bioactivity-guided isolation, the most potent immunosuppressive compound, periplocoside E (PSE), a pregnane glycoside, had been identified from P. sepium Bge. We investigated the immunosuppressive effects of PSE in vitro and in vivo. The results showed that PSE in a dose-dependent manner significantly inhibited the proliferation of splenocytes induced by concanavalin A and mixed lymphocyte culture reaction at no cytotoxic concentrations (<5 microM). Administration of PSE suppressed a delayed-type hypersensitivity reaction, and ovalbumin (OVA) induced antigen-specific immune responses in mice. In vivo treatment with PSE dose dependently suppressed OVA-induced proliferation and cytokine [interleukin (IL)-2 and interferon (IFN)-gamma] production from splenocytes in vitro. Purified T cells from OVA-immunized mice with PSE treatment showed its low ability for activation by OVA plus normal antigen presenting cell stimulation again in vitro. Further studies showed PSE dose dependently inhibited anti-CD3-induced primary T cell proliferation, activation for IL-2Ralpha (CD25) expression, and cytokine (IFN-gamma and IL-2) production also at the transcriptional level. PSE was highly specific and significantly inhibited the activation of extracellular signal-regulated kinase and Jun N-terminal kinase, whereas activation of p38 was not affected in T cells stimulated with anti-CD3. These results demonstrated that PSE is an immunosuppressive compound in P. sepium Bge, which directly inhibits T cell activation in vitro and in vivo. This study provided evidence to understand the therapeutic effects of P. sepium Bge and indicated that this herb is appropriate for treatment of T cell-mediated disorders, such as autoimmune diseases.

Clinical presentation, growth, and pubertal development in Addison's disease.

The clinical course of eight boys and six girls with Addison's disease has been reviewed. Adrenal antibodies were found in five boys and five girls, and four children showed clinical evidence of other autoimmune disease (hypoparathyroidism (three); diabetes (one)). The presentation was insidious in 12 children but acute in two. On treatment, linear growth was normal and, with the exception of one girl with theca cell antibodies, pubertal development proceeded normally in the older patients.