Inhibition of transcription factors by anti-inflammatory and anti-rheumatic drugs: can variability in response be overcome?

Inhibition of inflammatory arthritis using fullerene nanomaterials

Inflammatory arthritis (e.g. rheumatoid arthritis; RA) is a complex disease driven by the interplay of multiple cellular lineages. Fullerene derivatives have previously been shown to have anti-inflammatory capabilities mediated, in part, by their ability to prevent inflammatory mediator release by mast cells (MC). Recognizing that MC can serve as a cellular link between autoantibodies, soluble mediators, and other effector populations in inflammatory arthritis, it was hypothesized that fullerene derivatives might be used to target this inflammatory disease. A panel of fullerene derivatives was tested for their ability to affect the function of human skin-derived MC as well as other lineages implicated in arthritis, synovial fibroblasts and osteoclasts. It is shown that certain fullerene derivatives blocked FcγR- and TNF-α-induced mediator release from MC; TNF-α-induced mediator release from RA synovial fibroblasts; and maturation of human osteoclasts. MC inhibition by fullerene derivatives was mediated through the reduction of mitochondrial membrane potential and FcγR-mediated increases in cellular reactive oxygen species and NF-κB activation. Based on these in vitro data, two fullerene derivatives (ALM and TGA) were selected for in vivo studies using K/BxN serum transfer arthritis in C57BL/6 mice and collagen-induced arthritis (CIA) in DBA/1 mice. Dye-conjugated fullerenes confirmed localization to affected joints in arthritic animals but not in healthy controls. In the K/BxN moldel, fullerenes attenuated arthritis, an effect accompanied by reduced histologic inflammation, cartilage/bone erosion, and serum levels of TNF-α. Fullerenes remained capable of attenuating K/BxN arthritis in mast cell-deficient mice Cre-Master mice, suggesting that lineages beyond the MC represent relevant targets in this system. These studies suggest that fullerene derivatives may hold promise both as an assessment tool and as anti-inflammatory therapy of arthritis.

Anti-inflammatory activity of nanocrystalline silver-derived solutions in porcine contact dermatitis

Background

Nanocrystalline silver dressings have anti-inflammatory activity, unlike solutions containing Ag⁺ only, which may be due to dissolution of multiple silver species. These dressings can only be used to treat surfaces. Thus, silver-containing solutions with nanocrystalline silver properties could be valuable for treating hard-to-dress surfaces and inflammatory conditions of the lungs and bowels. This study tested nanocrystalline silver-derived solutions for anti-inflammatory activity.

Methods

Inflammation was induced on porcine backs using dinitrochlorobenzene. Negative and positive controls were treated with distilled water. Experimental groups were treated with solutions generated by dissolving nanocrystalline silver in distilled water adjusted to starting pHs of 4 (using CO₂), 5.6 (as is), 7, and 9 (using Ca(OH)₂). Solution samples were analyzed for total silver. Daily imaging, biopsying, erythema and oedema scoring, and treatments were performed for three days. Biopsies were processed for histology, immunohistochemistry (for IL-4, IL-8, IL-10, TNF-α, EGF, KGF, KGF-2, and apoptotic cells), and zymography (MMP-2 and -9). One-way ANOVAs with Tukey-Kramer post tests were used for statistical analyses.

Results

Animals treated with pH 7 and 9 solutions showed clear visual improvements. pH 9 solutions resulted in the most significant reductions in erythema and oedema scores. pH 4 and 7 solutions also reduced oedema scores. Histologically, all treatment groups demonstrated enhanced re-epithelialisation, with decreased inflammation. At 24 h, pMMP-2 expression was significantly lowered with pH 5.6 and 9 treatments, as was aMMP-2 expression with pH 9 treatments. In general, treatment with silver-containing solutions resulted in decreased TNF-α and IL-8 expression, with increased IL-4, EGF, KGF, and KGF-2 expression. At 24 h, apoptotic cells were detected mostly in the dermis with pH 4 and 9 treatments, nowhere with pH 5.6, and in both the epidermis and dermis with pH 7. Solution anti-inflammatory activity did not correlate with total silver content, as pH 4 solutions contained significantly more silver than all others.

Conclusions

Nanocrystalline silver-derived solutions appear to have anti-inflammatory/pro-healing activity, particularly with a starting pH of 9. Solutions generated differently may have varying concentrations of different silver species, only some of which are anti-inflammatory. Nanocrystalline silver-derived solutions show promise for a variety of anti-inflammatory treatment applications.

Guggulsterone blocks IL-1beta-mediated inflammatory responses by suppressing NF-kappaB activation in fibroblast-like synoviocytes

Guggulsterone is a plant sterol that is used to treat hyperlipidemia, arthritis, and obesity. Although its anti-inflammatory and anti-hyperlipidemic effects have been well documented, the effect of guggulsterone on fibroblast-like synoviocytes (FLS) has not yet been reported. Therefore, in this study, the effect of guggulsterone on interleukin (IL)-1beta-induced inflammatory responses in the FLS of rheumatic patients was investigated. Treatment of FLS with IL-1beta induced production of chemokines such as RANTES and ENA-78. In addition, Western blot analysis and gelatin zymography revealed that IL-1beta activated matrix metalloproteinase (MMP)-1 and -3 in FLS. However, pre-incubation with guggulsterone completely inhibited the ability of IL-1beta to induce the production of chemokines and to activate MMPs. Although the NF-kappaB binding activity and nuclear p50 and p65 subunit levels, as well as IkappaBalpha degradation in the cytoplasm was greater in cells stimulated with IL-1beta than in unstimulated cells, treatment with guggulsterone abolished all of these increases. Collectively, these results suggest that guggulsterone would be useful as an inhibitor of joint destruction in patients with rheumatoid arthritis.

The anti-inflammatory effect of A3 adenosine receptor agonists: a novel targeted therapy for rheumatoid arthritis

Targeting the A(3) adenosine receptor (A(3)AR) to combat inflammation is a new concept based on two findings. First, A(3)AR is highly expressed in inflammatory cells, whereas low expression is found in normal tissues. This receptor was also found to be overexpressed in peripheral blood mononuclear cells, reflecting receptor status in the remote inflammatory process. Second, A(3)AR activation with a specific agonist induces de-regulation of the NF-kappaB signaling pathway in inflammatory cells, as well as initiation of immunomodulatory effects. The A(3)AR agonist CF-101 (known generically as IB-MECA) induces anti-inflammatory effects in experimental animal models of collagen- and adjuvant-induced arthritis. Combined therapy with CF-101 and methotrexate in adjuvant-induced arthritis rats yielded an additive anti-inflammatory effect. Methotrexate induced upregulation of A(3)AR, rendering the inflammatory cells more susceptible to CF-101. In Phase I and in Phase IIa human studies, CF-101 was safe, well tolerated and showed strong evidence of an anti-inflammatory effect in rheumatoid arthritis patients. In peripheral blood mononuclear cells withdrawn from the patients at base line, a statistically significant correlation between A(3)AR expression level and response to the drug was noted. It is suggested that A(3)AR may serve as a biologic marker to predict patient response to the drug. Taken together, this information suggests that A(3)AR agonists may be a new family of orally bioavailable drugs to be developed as potent inhibitors of autoimmune-inflammatory diseases.

FMRP RNA targets: identification and validation

The Fragile X Syndrome is caused by the loss of function of the FMR1 gene (Pieretti et al. 1991. Cell 66, 817-822; O'Donnell & Warren 2002. Annu Rev Neurosci 25, 315-338]. Identification of the RNA targets to which FMRP binds is a key step in understanding the function of the protein and the cellular defects caused by its absence (Darnell et al. 2004 Ment Retard Dev Disabil Res Rev 10, 49-52). Here we discuss the current understanding of FMRP as an RNA-binding protein, the different approaches that have been taken to identify FMRP RNA targets and the relevance of some of these approaches to FMRP biology. In addition, we present evidence that point mutations in the K-homology (KH)1 or KH2 domains of FMRP abrogate its polyribosome association in transfected neuroblastoma cells but that the deletion of the RGG box does not. This suggests that RNA binding by the RGG box of FMRP may mediate other aspects of cellular mRNA metabolism such as mRNA localization or that it may have a role downstream of polyribosome association.

Inhibition of cytokine production by hymenialdisine derivatives

We describe herein the synthesis and biological activity of two indoloazepines that are structurally related to the marine sponge metabolite hymenialdisine. The natural product hymenialdisine was found to be a potent inhibitor of interleukin-2 (IC(50) = 2.4 microM) and tumor necrosis factor alpha (IC(50) = 1.4 microM) production. One of the hymenialdisine derived indoloazepines was found to also inhibit interleukin-2 (IC(50) = 3.5 microM) and tumor necrosis factor alpha (IC(50) = 8.2 microM) production.

The interplay between the glucocorticoid receptor and nuclear factor-kappaB or activator protein-1: molecular mechanisms for gene repression

The inflammatory response is a highly regulated physiological process that is critically important for homeostasis. A precise physiological control of inflammation allows a timely reaction to invading pathogens or to other insults without causing overreaction liable to damage the host. The cellular signaling pathways identified as important regulators of inflammation are the signal transduction cascades mediated by the nuclear factor-kappaB and the activator protein-1, which can both be modulated by glucocorticoids. Their use in the clinic includes treatment of rheumatoid arthritis, asthma, allograft rejection, and allergic skin diseases. Although glucocorticoids have been widely used since the late 1940s, the molecular mechanisms responsible for their antiinflammatory activity are still under investigation. The various molecular pathways proposed so far are discussed in more detail.

Inhibition of TPA-induced NF-kappaB nuclear translocation and production of NO and PGE2 by the anti-rheumatic gold compounds

Auranofin, aurothioglucose and aurothiomalate (10 microM each) inhibited 12-O-tetradecanoylphorbol 13-acetate (TPA, 16.2 nM)-induced nuclear translocation of nuclear factor-kappa B (NF-kappaB), and production of nitric oxide (NO) and prostaglandin E(2) (PGE(2)) in rat peritoneal macrophages when the cells were pre-incubated with each gold compound for 20 h. Without pre-incubation for 20 h, aurothioglucose and aurothiomalate, but not auranofin, failed to inhibit the TPA-induced NF-kappaB nuclear translocation and production of NO and PGE(2). Auranofin, aurothioglucose and aurothiomalate did not affect the direct binding of NF-kappaB to the DNA probe. It was suggested that these gold compounds inhibit the TPA-induced production of NO and PGE(2) by inhibiting the NF-kappaB nuclear translocation.

Placental imbalance of vasoactive factors does not affect pregnancy outcome in patients treated with Cyclosporine A after transplantation

Endothelin-1 (ET-1) and nitric oxide (NO) have been suggested to have a focal role in the regulation of placental and fetal growth. Cyclosporine A (CsA) has been shown to strongly modulate ET-1 and NO synthesis and thus has the potential to affect fetal growth and maternal state. Eleven CsA-treated female kidney transplant recipients were recruited. Fourteen healthy pregnant women served as controls. Placental expression of ET-1 and tissue factor (TF) was evaluated by in situ hybridization, and NO synthase (NOS) was evaluated by staining with the reduced form of nicotinamide-adenine dinucleotide phosphate (NADPH)-diaphorase and in situ hybridization. Kidney transplant recipients showed a marked reduction in NADPH-diaphorase staining, as well as endothelial constitutive NOS (ecNOS) messenger RNA, whereas inducible NOS expression was unchanged. Normal placenta showed a strong positive ET-1 signal along the endothelium of uteroplacental arteries within the basal plate, which increased markedly in decidua of transplant recipients. Thus, transplant recipients showed a remarkable alteration in ET-1/ecNOS balance without alteration in fetal growth or maternal renal function. Next, we explored the state of placental endothelial cell activation downstream from vasoactive factors by evaluating TF gene expression. Transplant recipients did not show modification of TF transcript compared with healthy pregnant women. CsA potently affected the placental ET-1/ecNOS vasoactive balance. Nevertheless, newborns from transplant recipient mothers were appropriate for gestational age, and transplant recipients did not show systemic hypertension or impending renal damage. It is suggested that CsA may blunt the activation of endothelial cells and priming of endothelial-derived substances, which possibly lie downstream from the cited vasoactive agents.

Transcription factors

The regulation of gene expression by transcription factors is fundamental to the phenotype of all cells. The activated phenotype of cells engaged in inflammatory processes is characterized by induced expression of a diverse set of genes, including cytokines, enzymes and cell adhesion molecules. A relatively small number of inducible transcription factors, particularly NF-kappaB, AP-1, NFATs and STATs, are responsible for the expression of a wide variety of inflammatory phenotypic characteristics and therefore play a central role in the pathogenesis of rheumatic diseases. Each of these transcription factors can be modified by existing anti-rheumatic and anti-inflammatory drugs, although adverse effects and limited efficacy remain problems. The future development of therapeutic agents with specificity for transcription factors, especially NF-kappaB, might lead to safer and more effective treatment.