Copper chelation with tetrathiomolybdate suppresses adjuvant-induced arthritis and inflammation-associated cachexia in rats

Roles and mechanisms of copper homeostasis and cuproptosis in osteoarticular diseases

Copper is an essential trace element in the human body that is extensively distributed throughout various tissues. The appropriate level of copper is crucial to maintaining the life activities of the human body, and the excess and deficiency of copper can lead to various diseases. The copper levels in the human body are regulated by copper homeostasis, which maintains appropriate levels of copper in tissues and cells by controlling its absorption, transport, and storage. Cuproptosis is a distinct form of cell death induced by the excessive accumulation of intracellular copper. Copper homeostasis and cuproptosis has recently elicited increased attention in the realm of human health. Cuproptosis has emerged as a promising avenue for cancer therapy. Studies concerning osteoarticular diseases have elucidated the intricate interplay among copper homeostasis, cuproptosis, and the onset of osteoarticular diseases. Copper dysregulation and cuproptosis cause abnormal bone and cartilage metabolism, affecting related cells. This phenomenon assumes a critical role in the pathophysiological processes underpinning various osteoarticular diseases, with implications for inflammatory and immune responses. While early Cu-modulating agents have shown promise in clinical settings, additional research and advancements are warranted to enhance their efficacy. In this review, we summarize the effects and potential mechanisms of copper homeostasis and cuproptosis on bone and cartilage, as well as their regulatory roles in the pathological mechanism of osteoarticular diseases (e.g., osteosarcoma (OS), osteoarthritis (OA), and rheumatoid arthritis (RA)). We also discuss the clinical-application prospects of copper-targeting strategy, which may provide new ideas for the diagnosis and treatment of osteoarticular diseases.

Copper Promotes LPS-Induced Inflammation via the NF-кB Pathway in Bovine Macrophages

Inflammation is a complex physiological process that enables the clearance of pathogens and repairing damaged tissues. Elevated serum copper concentration has been reported in cases of inflammation, but the role of copper in inflammatory responses remains unclear. This study used bovine macrophages to establish lipopolysaccharide (LPS)-induced inflammation model. There were five groups in the study: a group treated with LPS (100 ng/ml), a group treated with either copper chelator (tetrathiomolybdate, TTM) (20 μmol) or CuSO4 (25 μmol or 50 μmol) after LPS stimulation, and a control group. Copper concentrations increased in macrophages after the LPS treatment. TTM decreased mRNA expression of pro-inflammatory factors (IL-1β, TNF-α, IL-6, iNOS, and COX-2), whereas copper supplement increased them. Compared to the control group, TLP4 and MyD88 protein levels were increased in the TTM and copper groups. However, TTM treatment decreased p-p65 and increased IкB-α while the copper supplement showed reversed results. In addition, the phagocytosis and migration of bovine macrophages decreased in the TTM treatment group while increased in the copper treatment groups. Results mentioned above indicated that copper could promote the LPS-induced inflammatory response in bovine macrophages, promote pro-inflammatory factors by activating the NF-кB pathway, and increase phagocytosis capacity and migration. Our study provides a possible targeted therapy for bovine inflammation.

Mechanistic insights into the treatment of iron-deficiency anemia and arthritis in humans with dietary molybdenum

In the last few decades, there has been a resurgence in interest in the use of dietary supplements to treat diseases in humans and molybdenum has the potential to be used therapeutically. In humans, dietary molybdenum has been shown to treat iron-deficiency anemia and it may treat joint pain in arthritis. It has been proposed that the anti-anemic and tentative anti-arthritic properties of molybdenum are because it is increasing the activity of one or more mammalian molybdoenzymes. Molybdenum forms part of the active site of these enzymes. Despite this, it is unlikely that a molybdenum deficiency can develop in humans that are on an oral diet and not exposed to unsafe levels of a molybdenum antagonist. Therefore, the underlying mechanism by which dietary molybdenum treats or may treat these diseases is currently not known. This minireview examines three possible underlying mechanisms. It investigates the possibility that molybdenum: increases the quantity of active mammalian molybdoenzymes, restores or partially restores activity to malfunctioning mammalian molybdoenzymes, or blocks nuclear receptors, in cells. The examination of these mechanisms has provided an impression of the mechanism by which molybdenum treats iron-deficiency anemia and may treat arthritis; and hypothesize uses of molybdenum for other human diseases.

A new nutraceutical resource from a rare native plant growing in Turkey and for its spectro-chemical and biological insights: Endemic Diplotaenia bingolensis (Apiaceae)

The present study designed to investigate the quantitative distributions in the secondary metabolites and biological activity of sub-fractions obtained successively from water and methanol: dichloromethane (rate 1:1; v:v) solvent decoction of Diplotenia bingolensis aerial parts. The crude extracts were obtained from the aerial parts of the endemic D. bingolensis species refluxing with water and organic solvents. Sub-fractions of water extract were obtained by successive fractionation of the water extract with hexane (WH), dichloromethane (WD), ethyl acetate (WE) and n-butanol (WB), respectively. Sub-fractions of organic solvent were obtained by fractionation of the organic crude extract with hexane (OH), dichloromethane (OD), ethyl acetate (OE), n-butanol (OB) and water (OW), respectively. The total amount of phenols and flavonoids contained in each sub-fraction was analyzed by UV-VIS spectrophotometer, analysis of lipophilic components by GC-MS spectrometer, and quantitative analysis of hydrophilic components by HPLC-TOF/MS spectrophotometer. Furthermore, the biological activity of each sub-fraction was compared with different antioxidant activities such as DPPH radical scavenging activity and ferric ion reduction capacity. Sub-fraction WD (137.1 ± 2.1 μg QE/mg DI) and OE (127.1 ± 5.2 μg QE/mg DI) in terms of flavonoid content, sub-fraction WD (665.8 ± 47.6 μg GAE/mg DI) and OE (724.6 ± 43.6 μg GAE/mg DI) were the richest isolates in terms of total phenol content. Sub-fractions OH and OD contained linoleic acid (17.0 and 11.0%, respectively) and linolenic acid (22.1 and 18.5%, respectively). It was revealed that sub-fractions were rich in terms of rutin (1.2-47.2 μg HC/mg DI) and chlorogenic acid (0.1-12.1 μg HC/mg DI). Sub-fractions WD and OE were showed the highest DPPH radical scavenging activity with 46.4 ± 1.4 and 47.6 ± 10.0 μg/mL EC₅₀ values, respectively. This study is the first to demonstrate biological insight of the potential antioxidant activity of D. bingolensis. These findings warrant the popular use of the endemic D. bingolensis and highlight the potential of its active constituents in the development of new antioxidative drugs.

Tetrathiomolybdate, a copper chelator inhibited imiquimod-induced skin inflammation in mice

BACKGROUND

Copper is an essential metal for maintenance of many biological functions; however, excessive amount can induce inflammation and oxidative stress. Tetrathiomolybdate (TM) is a copper chelator for treatment of Wilson's disease, and decreased the severity of autoimmune arthritis in mice.

OBJECTIVE

In this report, we evaluated the effects of TM in a mouse model for psoriasis.

METHODS

Imiquimod-induced psoriasis murine model was used. We applied immunohistochemistry staining and ELISA to determine levels of cytokines in the inflamed skin, splenocytes, and draining lymph nodes. In addition, we used keratinocytes and splenocytes to test the inhibitory effects of TM on cytokine production and activation of transcription factors.

RESULTS

Our results showed that TM significantly reduced cumulative scores, epidermis thickness, and ki-67 expression in the inflamed skin. In addition, TM decreased skin cytokine levels and systemic inflammation. Moreover, TM suppressed activation in keratinocytes and splenocytes with reduction in phosphorylation of Erk1/2 and STAT3.

CONCLUSION

These findings are strong evidence that TM can inhibit psoriasis in the model.

Evidence for the anti-inflammatory activity of Bupleurum marginatum (Apiaceae) extracts using in vitro and in vivo experiments supported by virtual screening

OBJECTIVES

To explore the potential anti-inflammatory activity of Bupleurum marginatum extracts using in vitro and in vivo studies supported by virtual screening.

METHODS

Antioxidant activity was assessed using the DPPH˙ and inhibition of 2-deoxyribose degradation assays. Anti-inflammatory activity was determined in vitro by measuring the suppression of prostaglandin E₂ release (PGE₂ ) in pancreatic cancer cells (MIA-PaCa-2) and the inhibition of 5-lipoxygenase whereas the rat paw oedema was used in vivo. The major constituents were docked in 5-lipoxygenase and cyclooxygenase-II active sites.

KEY FINDINGS

Methanol and dichloromethane (DCM) extracts showed IC₅₀ of 46.99 and 162.99 μg/ml in the DPPH˙, 1.52 and 2.12 μg/ml in inhibition of 2-deoxyribose degradation assays, respectively. They reduced PGE₂ release by 41.33 and 52.85% at 25 μg/ml and inhibited 5-lipoxygenase with IC₅₀ of 45.28 and 25.92 μg/ml, respectively. 50 and 70% reduction in the diameter of the carrageenan-induced rat paws with methanol and DCM extracts, respectively, with a marked decline in the inflammation score was observed. Rutin, a predominating compound, showed a strong interaction with the key amino acids in 5-LOX active site with interaction energy of -74.59 kcal/mol.

CONCLUSIONS

Our study provides evidence for an interesting anti-inflammatory activity of B. marginatum aerial parts offering a natural anti-inflammatory agent.

Tetrathiomolybdate Treatment Leads to the Suppression of Inflammatory Responses through the TRAF6/NFκB Pathway in LPS-Stimulated BV-2 Microglia

Although the positive relationship between copper and Alzheimer's disease (AD) was reported by a lot of epidemiological data, the mechanism is not completely known. Copper is a redox metal and serves as a mediator of inflammation. Because the homeostasis of copper is altered in Aβ precursor protein (APP) and presenilin 1 (PS1) transgenic (Tg) mice, the using of copper chelators is a potential therapeutic strategy for AD. Here we report that a copper chelator, tetrathiomolybdate (TM), is a potential therapeutic drug of AD. We investigated whether TM treatment led to a decrease of pro-inflammatory cytokines in vivo and in vitro, and found that TM treatment reduced the expression of iNOS and TNF-α in APP/PS1 Tg mice through up-regulating superoxide dismutase 1 (SOD1) activity. In vitro, once stimulated, microglia secretes a variety of proinflammatory cytokines, so we utilized LPS-stimulated BV-2 cells as the inflammatory cell model to detect the anti-inflammatory effects of TM. Our results indicated that TM-pretreatment suppressed the ubiquitination of TRAF6 and the activation of NFκB without affecting the expression of TLR4 and Myd88 in vitro. By detecting the activity of SOD1 and the production of reactive oxygen species (ROS), we found that the anti-inflammatory effects of TM could be attributed to its ability to reduce the amount of intracellular bioavailable copper, and the production of ROS which is an activator of the TRAF6 auto-ubiquitination. Hence, our results revealed that TM-treatment could reduce the production of inflammatory cytokines by the suppression of ROS/TRAF6/AKT/NFκB signaling pathway.

Evaluation of anti-inflammatory potential of the ethanolic extract of the Saussurea lappa root (costus) on adjuvant-induced monoarthritis in rats

BACKGROUND

Rheumatoid arthritis (RA) is a systemic autoimmune disorder characterized by polyarticular symmetrical arthritis. The prevalence of RA is consistent worldwide, affecting about 0.5%-1.0% of the population. The aim of this study was to investigate whether Saussurea lappa (costus) could ameliorate adjuvant arthritis (AA) in the rat for 21 days.

METHODS

Animals were divided into eight groups (n=5/group). Group 1 acted as control, group 2 presented the AA rats (positive control), and groups 3, 4, and 5 were treated with different doses of S. lappa (200, 400, and 600 mg/kg, respectively), whereas groups 6, 7, and 8 were AA rats and orally administered with S. lappa (200, 400, and 600 mg/kg, respectively). The changes caused by chronic inflammation were evaluated through the measurement of ankle circumference (AC). Serum C-reactive protein (CRP), interleukins (IL-1β and IL-6), tumor necrosis factor α (TNF-α), total oxidative capacity (TOC), and total antioxidant capacity (TAC) were determined.

RESULTS

Saussurea lappa dose-dependently alleviated the severity of the disease based on the reduction in AC and on the clinical scores of the histological study. Histopathological examination proved that S. lappa decreased the infiltration of inflammatory cells and synovial hyperplasia as well as protected joint destruction. Saussurea lappa reduced the serum levels of CRP, TNF-α, IL-1β, and IL-6, reduced the TOC, and improved the TAC as compared with AA rats.

CONCLUSIONS

The S. lappa extract has potentially useful anti-arthritic activity as well as improves the immune and antioxidant responses of adjuvant-induced monoarthritis in rats.

Antinociceptive and anti-inflammatory effect of sulfated polysaccharide fractions from Sargassum wightii and Halophila ovalis in male Wistar rats

AIM

The aim of this objective is to evaluate the antinociceptive and anti-inflammatory potential of sulfated polysaccharide purified fractions isolated from brown seaweed Sargassum wightii and seagrass Halophila ovalis in male Wistar rats.

SUBJECTS AND METHODS

Crude sulfated polysaccharide from S. wightii and H. ovalis was subjected to anion exchange chromatography, and the chemical composition was investigated. The antinociceptive activity of purified fractions was investigated using formalin and hot plate test. Carrageenan-induced paw edema, peritonitis model, and Freund's Complete Adjuvant-induced arthritis model were employed to determine the anti-inflammatory activity.

RESULTS

In the formalin test, there was a significant reduction in licking time in both phases of the test at a dose of 10 mg/kg. In the hot plate test, the antinociceptive effect was observed only in animals treated with 5, 10 mg/kg suggesting that the analgesic effect occurs through a central action mechanism. Sw FrIV and Ho FrIV significantly inhibited paw edema induced by carrageenan, especially at 3 h after treatment and potentially decreased neutrophil migration at 10 mg/kg, respectively. In Freund's adjuvant-induced arthritic rats, a significant reduction in paw volume was observed in Sw FrIV and Ho FrIV-treated groups (10 mg/kg).

CONCLUSION

Purified components from S. wightii and H. ovalis have strong antinociceptive and anti-inflammatory effect on animal model. However, to determine the molecular mechanism, it is necessary to investigate the effect of purified fractions on inhibition of nitric oxide synthase expression mediated by inhibiting the phosphorylation of various signal proteins in lipopolysaccharide-stimulated RAW264.7 cells.

Evaluation of Anti-Inflammatory Potential of the New Ganghwaljetongyeum on Adjuvant-Induced Inflammatory Arthritis in Rats

Ganghwaljetongyeum (GHJTY) has been used as a standard treatment for arthritis for approximately 15 years at the Korean Medicine Hospital of Dongshin University. GHJTY is composed of 18 medicinal herbs, of which five primary herbs were selected and named new Ganghwaljetongyeum (N-GHJTY). The purpose of the present study was to observe the effect of N-GHJTY on arthritis and to determine its mechanism of action. After confirming arthritis induction using complete Freund's adjuvant (CFA) in rats, N-GHJTY (62.5, 125, and 250 mg/kg/day) was administered once a day for 10 days. In order to determine pathological changes, edema of the paws and weight were measured before and for 10 days after N-GHJTY administration. Cytokine (TNF-α, IL-1β, and IL-6) levels and histopathological lesions in the knee joint were also examined. Edema in the paw and knee joint of N-GHJTY-treated rats was significantly decreased at 6, 8, and 10 days after administration, compared to that in the CFA-control group, while weight consistently increased. Rats in N-GHJTY-treated groups also recovered from the CFA-induced pathological changes and showed a significant decline in cytokine levels. Taken together, our results showed that N-GHJTY administration was effective in inhibiting CFA-induced arthritis via anti-inflammatory effects while promoting cartilage recovery by controlling cytokine levels.

Anti-arthritic activity of luteolin in Freund's complete adjuvant-induced arthritis in rats by suppressing P2X4 pathway

To investigate anti-arthritic activity of luteolin (Lut) in Freund's complete adjuvant (FCA)-induced arthritis (AA) in rats. AA was induced by injecting with Freund's complete adjuvant (FCA). Male rats were randomly divided into five groups with 10 mice in each group: (1) control group (saline), (2) AA group, (3) AA+Diclofenac Sodium (AA+DS, 5 mg/kg), (4) AA+Lut (20 mg/kg), (5) AA+Lut (40 mg/kg). Male SD rats were subjected to treatment with Lut at 10 and 20 mg/kg from days 18 to 24 after immunization. Arthritic scores, tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), interleukin-6 (IL-6), interleukin-17 (IL-17), paw histopathology and the proteins of P2X4 pathway were assessed at the end of the experiment. Lut reduced the severity of arthritic scores during the experimental period as compared with positive control (RA). Lut significantly suppressed TNF-α, IL-6, IL-1β and IL-17 as compared with RA group. Histopathological examination indicated that Lut alleviated infiltration of inflammatory cells and synovial hyperplasia as well as protected joint destruction. Lut significantly suppressed P2X4, NLRP1, ASC, and Caspase-1p10. Lut may be a potential preventive or therapeutic candidate for the treatment of inflammation and arthritis.

Evaluation of the anti-arthritic activity of the hydroethanolic leaf extract of Alchornea cordifolia in rats

BACKGROUND

Different decoctions of Alchornea cordifolia leaves are used by Yoruba herbalists (Southwest Nigeria) for the local treatment of ulcers, rheumatic pains, febrile convulsions, and for enhancing physical performance.

MATERIALS AND METHODS

In this study, the anti-arthritic effect of 100 - 400 mg/kg/day of the hydroethanolic leaf extract of Alchornea cordifolia (HEAC) was investigated in Complete Freund's Adjuvant (CFA)-induced arthritic rats as a way of evaluating its efficacy in the local management of arthritis. In addition, the effects of HEAC on liver and renal function parameters as well as its effect on the antioxidant enzyme system were investigated. Arthritis was induced using 0.1 ml of 10 mg/ml of Complete Freund's Adjuvant (CFA) following 1 h oral pretreatment and 8(th) day post-arthritic induction with 100, 200 and 400 mg/kg/day of HEAC and 3 mg/kg/day of celecoxib as the reference drug. The anti-arthritic activity of HEAC was assessed based on the ability of HEAC to alter the paw edema diameter, body weight, full blood count, renal and liver function markers, glycoprotein, lysosomal enzymes and possible antioxidant potential in the arthritic rats.

RESULTS

Oral pretreatment with 100, 200, and 400 mg/kg/day of HEAC produced significant (p<0.001, p<0.05 and p<0.01) reductions in the paw edema diameter in a non-dose dependent fashion in ACF-induced arthritic rats with the 100 mg/kg/day of HEAC producing the most significant anti-arthritic effect. Similarly, HEAC increased hepatic GSH levels, CAT and SOD activities suggesting possible antioxidant mechanism for its anti-arthritic effect.

CONCLUSION

Overall, results of this study lend credence to the folkloric use of water decoction of Alchornea cordifolia leaves against rheumatoid arthritis. However, further pharmacological investigations would be required at isolating and determining the active anti-arthritic molecule(s) in HEAC in the nearest future.

Evaluation of Protective Efficacy of Avicennia marina (Forssk.) Vierh Leaves against Complete Freund᾽s Adjuvant-induced Arthritis in Wistar

Aviecennia marina (Avicenniaceae) is an endemic plant that widely distributed in the Southern parts of Iran. This plant has been used as treatment of rheumatism arthritis among the inhabitants of Southern parts of Iran. The Avicennia marina hydroalcoholic extract was prepared and its protective efficacy was investigated using measurement of ankle diameter, total WBC and RBC count, ESR, and Pro-inflammatory cytokines levels in the complete Freund᾽s adjuvant (CFA)-induced arthritic rat. The increment in ESR and total WBC, reduction in RBC count and hemoglobin levels observed in the arthritic animals were also found to be significantly restored in HEA treated rats. A. marina at 400 mg/Kg significantly decreases the serum pro-inflammatory cytokines as well as normalizes ankle diameter of CFA rats. A. marina (400 mg/Kg) significantly normalizes changes observed in arthritic rats to near normal conditions, indicates that A. marina has promising protective efficacy against arthritic rats.

Antiallergic and Antiarthritic Effects of Stem Bark Extract of Glyphaea brevis (Spreng) Monachino (Tiliaceae) in Murine Models

Background. Various parts of Glyphaea brevis (Spreng) Monachino (Tiliaceae) find a use in traditional medicine in the treatment of pain and oedema among others. This study evaluates the anti-inflammatory, antiallergic, and antiarthritic effects of a 70% (v/v) aqueous ethanol extract of the stem bark of Glyphaea brevis in murine models. Materials and Methods. The effect of the aqueous ethanol extract of Glyphaea brevis extract (GBE) was assessed on the maximal and total oedema responses in the carrageenan-induced paw oedema in mice to evaluate the acute anti-inflammatory actions of the extract. Systemic anaphylaxis was induced with compound 48/80 and survival rates monitored for 1 h in mice with prior treatment with GBE to assess the anti-allergic action of the extract. The indirect antihistamine effect of GBE was evaluated on clonidine-induced catalepsy. Rat adjuvant-induced arthritis model was used to study GBE's antiarthritic action. Results. GBE significantly suppressed the mean maximal swelling and the total paw swellings over 6 h in the carrageenan-induced paw oedema when administered either prophylactically or therapeutically. GBE dose dependently increased the time for compound 48/80-induced mortality. Administered either prophylactically or therapeutically, GBE inhibited clonidine-induced catalepsy while it had no effect on haloperidol-induced catalepsy. GBE caused a significant dose-dependent suppression of Freund's adjuvant-induced arthritis. Conclusion. Glyphaea brevis inhibits the in vivo degranulation of mast cells and thereby suppress allergy. In addition it exhibits anti-inflammatory action and attenuates Freund's adjuvant-induced arthritis. The results of this work contribute to validate the traditional use of Glyphaea brevis in the management of inflammatory disorders.

Antinociceptive and anti-inflammatory activities of Sargassum wightii and Halophila ovalis sulfated polysaccharides in experimental animal models

The present study investigated the effects of sulfated polysaccharides from brown seaweed Sargassum wightii (Sw-SP) and seagrass Halophila ovalis (Ho-SP) in nociceptive and inflammatory models. In the formalin test, Sw-SP and Ho-SP significantly reduced licking time in both phases of the test at a dose of 10 mg/kg. In the hot plate test, the antinociceptive effect was observed only in animals treated with 10 mg/kg of Sw-SP and 5, 10 mg/kg of Ho-SP, suggesting that the analgesic effect occurs through a central action mechanism at the higher dose. Sw-SP and Ho-SP (10 mg/kg) significantly inhibited paw edema induced by carrageenan, especially at 3 h after treatment and potentially decreased neutrophil migration by 53% and 52%, respectively. In Freund's adjuvant-induced arthritic rats, there was a significant increase in the rat paw volume and decrease in body weight, but in Sw-SP- and Ho-SP-treated groups (10 mg/kg), a significant reduction in paw volume and a normal gain in body weight were observed. The present results indicate that Sw-SP and Ho-SP possess antinociceptive and anti-inflammatory effects and have potential usefulness for development as therapeutic agents.

Novel method for rapid copper chelation assessment confirmed low affinity of D-penicillamine for copper in comparison with trientine and 8-hydroxyquinolines

Copper is an essential trace element involved in many physiological processes. Since disorder of copper homeostasis is observed in various pathologies, copper chelators may represent a promising therapeutic tool. This study was aimed at: 1) formation of an in vitro methodology for screening of copper chelators, and 2) detailed analysis of the interaction of copper with clinically used D-penicillamine (D-PEN), triethylenetetramine (trientine), experimentally tested 8-hydroxyquinolines, and the disodium salt of EDTA as a standard chelator. Methodology based on bathocuproinedisulfonic acid disodium salt (BCS), usable at (patho)physiologically relevant pHs (4.5-7.5), enabled assessment of both cuprous and cupric ions chelation and comparison of the relative affinities of the tested compounds for copper. In the case of potent chelators, the stoichiometry could be estimated too. Clioquinol, chloroxine and EDTA formed very stable complexes with Cu(+)/Cu(2+) at all tested pHs, while copper complexes with trientine were stable only under neutral or slightly acidic conditions. Non-substituted 8-hydroxyquinoline was a less efficient copper chelator, but still unequivocally more potent than D-PEN. Both 8-hydroxyquinoline and D-PEN chelation potencies, similarly to that of trientine, were pH-dependent and decreased with pH. Moreover, only D-PEN was able to reduce cupric ions. Conclusively, BCS assay represents a rapid, simple and precise method for copper chelation measurement. In addition, lower binding affinity of D-PEN compared with 8-hydroxyquinolines and trientine was demonstrated.

6b,11b-Dihydroxy-6b,11b-dihydro-7H-indeno[1,2-b]naphtho[2,1-d]furan-7-one (DHFO), a small molecule targeting NF-κB, demonstrates therapeutic potential in immunopathogenic chronic inflammatory conditions

6b,11b-Dihydroxy-6b,11b-dihydro-7H-indeno[1,2-b]naphtho[2,1-d]furan-7-one (DHFO), an easily synthesisable, orally bioavailable and relatively non-toxic small molecule synthesised in our lab, was previously reported to possess anti-oxidant, 5-lipoxygenase inhibitory, anti-inflammatory and peripheral analgesic activities. The present work deals with exploration of DHFO's efficacy in immunopathogenic chronic inflammatory conditions - arthritis and allergy. In carrageenan-induced inflammatory air pouch, which resembles the arthritic synovium, DHFO effectively reduced inflammatory redness and swelling and neutrophil infiltration. In complete Freund's adjuvant-induced arthritis, DHFO significantly decreased paw oedema and nitrite levels with efficacy comparable to diclofenac. DHFO inhibited neutrophil activation (observed as decreased myeloperoxidase levels), in both the in vivo models of inflammation. Interestingly, DHFO did not ulcerate the gastrointestinal tract, while diclofenac was observed to be extremely ulcerogenic. In antigen-induced active and passive anaphylaxis (allergy) models, DHFO dose-dependently prevented mesenteric mast cell (MC) degranulation with efficacy comparable to ketotifen. DHFO also inhibited compound 48/80 (C48/80)-induced paw oedema and peritoneal MC degranulation. DHFO stabilised p815 murine MCs stimulated by C48/80 and calcium ionophore-A23187, indicating an action downstream of calcium mobilisation. DHFO's anti-allergic mechanism could be two-pronged involving (1) inhibition of IgE production and/or (2) MC stabilisation. DHFO inhibited lipopolysaccharide (LPS)-induced pro-inflammatory mediator release (ROS, NO, IL-6 levels) and COX2 expression in RAW264.7 murine macrophages. Protein expression studies confirmed DHFO's ability to reduce nuclear levels of NF-κB in LPS-stimulated macrophages. Thus, DHFO is a promising non-ulcerogenic synthetic small molecule lead for immunopathogenic chronic inflammatory conditions.

Ameliorative effect of Drynaria quercifolia (L.) J. Sm., an ethnomedicinal plant, in arthritic animals

Drynaria quercifolia (L.) J. Sm., is an ethnomedicinal plant used widely in Tamil Nadu to treat arthritis. The present study was aimed to evaluate the traditional claim of D. quercifolia rhizome water extract in adjuvant induced arthritic animals. Anti-arthritic effect was studied by assessing the levels of lysosomal enzymes, protein bound carbohydrates, urinary degradative collagen and serum cytokines on control and adjuvant induced arthritis. The paw swelling and body weight were also analyzed. The levels of ROS and lysosomal enzymes in neutrophils of control and adjuvant induced animals were also estimated. D. quercifolia rhizome water extract at doses of 100 and 200mg/kg reduced the paw thickness and elevated the mean body weight of arthritic rats. The treatment with extract showed a significant reduction in the levels of plasma and liver lysosomal enzymes as well as protein bound carbohydrates and urinary degradative collagen levels. The treatment reduced the levels of ROS and lysosomal enzymes in neutrophils significantly. The significant reduction in the levels of serum pro-inflammatory cytokines (TNF-α and IL-1β) and the increment in the levels of anti-inflammatory cytokine (IL-10) were also observed by the treatment. The present study supports the traditional claim of using D. quercifolia to treat rheumatism.

Copper complexes as therapeutic agents

The importance of transition metals in biological processes has been well established. Copper (Cu) is a transition metal that can exist in oxidised and reduced states. This allows it to participate in redox and catalytic chemistry, making it a suitable cofactor for a diverse range of enzymes and molecules. Cu deficiency or toxicity is implicated in a variety of pathological conditions; therefore inorganic complexes of Cu have been investigated for their therapeutic and diagnostic potential. These Cu complexes have been shown to be effective in cancer treatment due to their cytotoxic action on tumour cells. Alternatively, Cu complexes can also modulate Cu homeostasis in the brain, resulting in protective effects in several models of neurodegeneration. In other diseases such as coronary heart disease and skin disease, the success of Cu complexes as potential therapeutics will most likely be due to their ability to increase SOD activity, leading to relief of oxidative stress. This review seeks to provide a broad insight into some of the diverse actions of Cu complexes and demonstrate the strong future for these compounds as potential therapeutic agents.

Copper chelation by tetrathiomolybdate inhibits lipopolysaccharide-induced inflammatory responses in vivo

Redox-active transition metal ions, such as iron and copper, may play an important role in vascular inflammation, which is an etiologic factor in atherosclerotic vascular diseases. In this study, we investigated whether tetrathiomolybdate (TTM), a highly specific copper chelator, can act as an anti-inflammatory agent, preventing lipopolysaccharide (LPS)-induced inflammatory responses in vivo. Female C57BL/6N mice were daily gavaged with TTM (30 mg/kg body wt) or vehicle control. After 3 wk, animals were injected intraperitoneally with 50 μg LPS or saline buffer and killed 3 h later. Treatment with TTM reduced serum ceruloplasmin activity by 43%, a surrogate marker of bioavailable copper, in the absence of detectable hepatotoxicity. The concentrations of both copper and molybdenum increased in various tissues, whereas the copper-to-molybdenum ratio decreased, consistent with reduced copper bioavailability. TTM treatment did not have a significant effect on superoxide dismutase activity in heart and liver. Furthermore, TTM significantly inhibited LPS-induced inflammatory gene transcription in aorta and heart, including vascular and intercellular adhesion molecule-1 (VCAM-1 and ICAM-1, respectively), monocyte chemotactic protein-1 (MCP-1), interleukin-6, and tumor necrosis factor (TNF)-α (ANOVA, P < 0.05); consistently, protein levels of VCAM-1, ICAM-1, and MCP-1 in heart were also significantly lower in TTM-treated animals. Similar inhibitory effects of TTM were observed on activation of nuclear factor-κB (NF-κB) and activator protein-1 (AP-1) in heart and lungs. Finally, TTM significantly inhibited LPS-induced increases of serum levels of soluble ICAM-1, MCP-1, and TNF-α (ANOVA, P < 0.05). These data indicate that copper chelation with TTM inhibits LPS-induced inflammatory responses in aorta and other tissues of mice, most likely by inhibiting activation of the redox-sensitive transcription factors, NF-κB and AP-1. Therefore, copper appears to play an important role in vascular inflammation, and TTM may have value as an anti-inflammatory or anti-atherogenic agent.

Topical metal chelation therapy ameliorates oxidation-induced toxicity in diabetic cataract

Oxidative stress plays a critical role in cataractogenesis, the leading cause of blindness worldwide. Since transition metals generate reactive oxygen species (ROS) formation, metal chelation therapy has been proposed for treatment of cataracts. However, the effectiveness of most chelators is limited by low tissue penetrability. This study is the first to demonstrate that the topically applied divalent metal chelator ethylenediamine tetraacetic acid (EDTA) combined with the carrier and permeability enhancer methyl sulfonyl methane (MSM) ameliorates both oxidation-induced lens opacification and the associated toxic accumulation of protein-4-hydroxynonenal (HNE) adducts. Both in vitro (rat lens culture) and in vivo (diabetic rats), EDTA-MSM (1) significantly reduced lens opacification by about 40-50%, (2) significantly diminished lens epithelial cell proliferation and fiber cell swelling in early stages of cataract formation in vivo, and (3) notably decreased the levels of protein-HNE adducts. These findings have important implications specifically for the treatment of cataract and generally for other diseases in which oxidative stress plays a key pathogenic role.

Do cytokines have any role in Wilson's disease?

The aim of this study was to determine the serum cytokine levels in patients with Wilson's disease (WD) and correlate with phenotype, therapeutic status and laboratory data. In this cross-sectional study, the serum levels of cytokines were estimated in 34 patients (M : F, 23 : 11; drug-naive, 11) with WD (mean age: 13.8 +/- 8.6 and 19.6 +/- 9.03 years) and compared with 30 controls. The following serum cytokines were analysed using enzyme-linked immunosorbent assay: (i) tumour necrosis factor (TNF)-alpha, (ii) interferon (IFN)-gamma, (iii) interleukin (IL)-2, (iv) IL-6 and (v) IL-4. Serum TNF-alpha (P < 0.001), IFN-gamma (P = 0.005) and IL-6 (P < 0.001) were detectable in WD compared with controls. However, serum level elevation of IL-4 (P = 0.49) and IL-2 (P = 0.11), although detectable compared with controls, was statistically insignificant. The disease severity and therapeutic status did not affect the cytokines. Presence of anaemia, leucopenia, thrombocytopenia, pancytopenia and hepatic dysfunction did not influence cytokine levels. There was a significant negative correlation between IL-6 and ceruloplasmin (P = 0.04) and anti-inflammatory cytokines (IL-4) and copper level (P = 0.01). Serum cytokines, both proinflammatory and anti-inflammatory subtypes, were elevated significantly in patients with WD. Further studies would establish their role in its pathogenesis.

Secretion without Golgi

A growing number of proteins devoid of signal peptides have been demonstrated to be released through the non-classical pathways independent of endoplasmic reticulum and Golgi. Among them are two potent proangiogenic cytokines FGF1 and IL1alpha. Stress-induced transmembrane translocation of these proteins requires the assembly of copper-dependent multiprotein release complexes. It involves the interaction of exported proteins with the acidic phospholipids of the inner leaflet of the cell membrane and membrane destabilization. Not only stress, but also thrombin treatment and inhibition of Notch signaling stimulate the export of FGF1. Non-classical release of FGF1 and IL1alpha presents a promising target for treatment of cardiovascular, oncologic, and inflammatory disorders.

Tetrathiomolybdate protects against bile duct ligation-induced cholestatic liver injury and fibrosis

Tetrathiomolybdate (TM), a potent copper-chelating drug, was initially developed for the treatment of Wilson's disease. Our working hypothesis is that the fibrotic pathway is copper-dependent. Because biliary excretion is the major pathway for copper elimination, a bile duct ligation (BDL) mouse model was used to test the potential protective effects of TM. TM was given in a daily dose of 0.9 mg/mouse by means of intragastric gavage 5 days before BDL. All the animals were killed 5 days after surgery. Plasma liver enzymes and total bilirubin were markedly decreased in TM-treated BDL mice. TM also inhibited the increase in plasma levels of tumor necrosis factor (TNF)-alpha and transforming growth factor (TGF)-beta1 seen in BDL mice. Cholestatic liver injury was markedly attenuated by TM treatment as shown by histology. Hepatic collagen deposition was significantly decreased, and it was paralleled by a significant suppression of hepatic smooth muscle alpha-actin and fibrogenic gene expression in TM-treated BDL mice. Although the endogenous antioxidant ability was enhanced, oxidative stress as shown by malondialdehyde and 4-hydroxyalkenals, hepatic glutathione/oxidized glutathione ratio, was not attenuated by TM treatment, suggesting the protective mechanism of TM may be independent of oxidative stress. In summary, TM attenuated BDL-induced cholestatic liver injury and fibrosis in mice, in part by inhibiting TNF-alpha and TGF-beta1 secretion. The protective mechanism seems to be independent of oxidative stress. Our data provide further evidence that TM might be a potential therapy for hepatic fibrosis.

Effect of allopurinol and vitamin e on rat model of rheumatoid arthritis

OBJECTIVES

Rat collagen II-induced arthritis is a model of chronic inflammation induced by mycobacterium butyricum and collagen II. It is characterized by similar pathophysiological and pathobiochemical changes as rheumatoid arthritis (RA) in humans. In the present study, the biochemical effects of vitamin E and allopurinol (Allo) on RA of rats were investigated.

METHODS

Forty male rats were divided into four groups (10 rats each): control group, collagen II-induced RA group (CII group), CII group treated with allopurinol (CII+ Allo), and CII group treated with vitamin E (CII + Vit E). After 6 weeks of treatment, the plasma levels of lipid peroxides (LPO), nitric oxide (NO), ceruloplasmin (CP), superoxide dismutase (SOD), uric acid (UA) and glutathione (GSH) were detected using colorimetric methods. The plasma levels of PGE2 were measured using ELISA assay. The plasma levels of copper (Cu) and zinc (Zn) were determined using atomic absorption spectrometer.

RESULTS

In CII treated group, the levels of LPO, NO, PGE2, UA, CP and Cu were significantly higher, but the levels of SOD, GSH and Zn were significantly lower than controls. In CII + Allo treated group, the levels of SOD and GSH were significantly increased, but the levels of PGE2, LPO, NO, UA, Cu and CP were significantly decreased in comparison with CII-treated group. The levels of SOD, GSH and Zn were significantly increased, but the levels of PGE2, NO and CP were significantly decreased in the vitamin E treated group in comparison with CII-treated group. The levels of PGE2, LPO, Cu and Zn were significantly lower in vitamin E treated group than Allo-treated group. In conclusion, the study suggests that proper antioxidant intake management may reduce free radical generation and improve antioxidant status in RA. Allopurinol and vitamins E may effectively normalize in different degrees the impaired the oxidant/antioxidant system and may be useful in delaying the complication of RA. Moreover, they display anti-inflammatory action by decreasing PGE2 level in RA.

Solution equilibria of copper(II) complexation with N,N′-(2,2′-azanediylbis(ethane-2,1-diyl))dipicolinamide: A bio-distribution and dermal absorption study

The protonation equilibria of a pentadentate ligand, N,N'-(2,2'-azanediylbis(ethane-2,1-diyl))dipicolinamide ([H(2)(5555)-N]) and the complexation of this ligand with Cu(II) Ca(II), Zn(II) and Ni(II) have been studied by pH-potentiometry, (1)H NMR spectroscopy and UV-vis spectrophotometry. (1)H NMR detected the protonation of the pyridyl groups and formation of Cu[H(2)(5555)-N]H species at low pH, while amide group deprotonation at higher pH resulted in the formation of Cu[H(2)(5555)-N]H(-1) and Cu[H(2)(5555)-N]H(-2) species in solution. Potentiometric detection of protonated species was limited by the acidic nature of the pyridyl nitrogen donors. From UV-vis spectroscopy it is suggested that the amide nitrogens are coordinated. This conclusion is supported by Molecular Mechanics calculations. Water-octanol partition coefficients for the Cu(II)-[H(2)(5555)-N] system indicated that although the Cu[H(2)(5555)-N]H(-1) species is largely hydrophilic, approximately 54% of the complex goes into the organic phase. This percentage is able to promote dermal absorption of copper with a calculated penetration rate of 1.92x10(-1)cmh(-1). This was confirmed by dermal absorption studies which illustrate the role of hydrophobicity in promoting percutaneous drug administration.

Molecular changes evoked by triethylenetetramine treatment in the extracellular matrix of the heart and aorta in diabetic rats

Most patients with diabetes die from cardiac or arterial disease, for which there are limited therapeutic options. Free Cu(2+) ions are strongly pro-oxidant, and chelatable-Cu(II) is increased in the diabetic heart. We reported previously that treatment by Cu(II)-selective chelation with triethylenetetramine (TETA) evokes elevated urinary Cu(II) in diabetic rats and humans in whom it also improved hallmarks of established left ventricular (LV) disease. Here, we treated diabetic rats with TETA and evaluated its ability to ameliorate Cu(2+)-mediated LV and arterial damage by modifying the expression of molecular targets that included transforming growth factor (TGF)-beta1, Smad4, extracellular matrix (ECM) proteins, extracellular superoxide dismutase (EC-SOD), and heparan sulfate (HS). Eight-weeks of TETA treatment significantly improved cardiac diastolic function but not [glucose](plasma) in diabetic animals. LV and aortic mRNAs corresponding to TGF-beta1, Smad4, collagen types I, III, and IV, and fibronectin-1, and plasminogen activator inhibitor-1, were elevated in untreated diabetic animals and normalized after TETA treatment. EC-SOD mRNA and protein, and [HS](tissue) were significantly decreased in diabetes and restored by drug treatment. Candidate molecular mechanisms by which TETA could ameliorate diabetic cardiac and arteriovascular disease include the suppression of an activated TGF-beta/Smad signaling pathway that mediates increased ECM gene expression and restoration of normal EC-SOD and HS regulation. These findings are relevant to the restoration toward normal by TETA treatment of cardiac and arterial structure and function in diabetes.