Trace elements in regulation of NF-kappaB activity

Low-level Cu-fortification of bovine lactoferrin: Focus on its effect on in vitro anti-inflammatory activity in LPS-stimulated macrophages

Bovine lactoferrin (LF) per 1 g was reacted with 0.16, 0.32, and 0.64 mg CuCl₂ to reach 10%, 20%, and 40% copper-saturation, respectively, aiming to assess their anti-inflammatory activities to lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. The macrophages treated with CuCl₂ at 0.051 μg/mL dose did not have obvious change in cell viability, lactate dehydrogenase (LDH) release, and intracellular reactive oxygen species (ROS) production. However, LF and Cu-fortified LF products (10-80 μg/mL doses) mostly showed inhibitory effects on the stimulated macrophages dose-dependently. Moreover, Cu-fortified LF products of lower Cu-fortifying levels at lower doses exerted weaker inhibition on the stimulated macrophages than LF, leading to higher cell viability but decreased LDH release. Meanwhile, LF and Cu-fortified LF products at 10 and 20 μg/mL doses showed different activities to the stimulated cells, via partly decreasing or increasing the production of inflammatory mediators namely prostaglandin E₂ (PGE₂), nitric oxide, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), IL-1β, and ROS production, depending on the used Cu-fortifying and dose levels. Compared with LF, Cu-fortified LF product (Cu-fortifying level of 0.16 mg/g LF) at 10 μg/mL dose showed enhanced inhibition on the production of PGE₂, ROS, IL-1β, and TNF-α, evidencing increased anti-inflammatory activity. However, the inhibition of Cu-fortified LF product (Cu-fortifying level of 0.32 mg/g LF) at 20 μg/mL dose on the production of these inflammatory mediators was mostly reduced. It is thus proposed that both Cu-fortifying and dose levels could affect LF's anti-inflammatory activity in LPS-stimulated macrophages, while the Cu-fortifying level of LF could govern activity change.

Diet and Hygiene in Modulating Autoimmunity During the Pandemic Era

The immune system is an efficiently toned machinery that discriminates between friends and foes for achieving both host defense and homeostasis. Deviation of immune recognition from foreign to self and/or long-lasting inflammatory responses results in the breakdown of tolerance. Meanwhile, educating the immune system and developing immunological memory are crucial for mounting defensive immune responses while protecting against autoimmunity. Still to elucidate is how diverse environmental factors could shape autoimmunity. The emergence of a world pandemic such as SARS-CoV-2 (COVID-19) not only threatens the more vulnerable individuals including those with autoimmune conditions but also promotes an unprecedented shift in people's dietary approaches while urging for extraordinary hygiene measures that likely contribute to the development or exacerbation of autoimmunity. Thus, there is an urgent need to understand how environmental factors modulate systemic autoimmunity to better mitigate the incidence and or severity of COVID-19 among the more vulnerable populations. Here, we discuss the effects of diet (macronutrients and micronutrients) and hygiene (the use of disinfectants) on autoimmunity with a focus on systemic lupus erythematosus.

Arsenic (III) induces oxidative stress and inflammation in the gills of common carp, which is ameliorated by zinc (II)

Arsenic (As) is widely present in the environment in form of arsenite (As^III) and arsenate (As^V). Oxidative stress and inflammation are believed to be the dominant mechanisms of As^III toxicity in vivo and in vitro. The aim of this study was to investigate whether zinc (Zn²⁺) alleviates exogenous gill toxicity in carp induced by As^III and to gain insight into the underlying mechanisms. Exposure of carp to 2.83 mg As₂O₃/L for 30 days reduced superoxide dismutase activity by 4.0%, catalase by 41.0% and glutathione by 19.8%, while the concentration of malondialdehyde was increased by 16.4% compared to the control group, indicating oxidative stress. After the exposure of carp to As^III the expression of inflammatory markers, such as interleukin-6, interleukin-8, tumor necrosis factor α and inducible nitric oxide synthase in gill tissue were significantly increased. In addition, the phosphorylation of nuclear factor kappa-B (NF-κB) was increased by 225%. 1 mg ZnCl₂/L can relieve the toxicity of As^III based on histopathology, antioxidase activity, qRT-PCR and western results. Zn²⁺ attenuated As^III-induced gill toxicity that suppressed intracellular oxidative stress and NF-κB pathway by an upregulation of metallothionein. Therefore, the toxic effect of As^III on the gill cells of carp was reduced. This study provides a theoretical basis for exploring the alleviation of the toxic effects of metalloids on organisms by heavy metals and the biological assessment of the effects.

The Crossroads between Host Copper Metabolism and Influenza Infection

Three main approaches are used to combat severe viral respiratory infections. The first is preemptive vaccination that blocks infection. Weakened or dead viral particles, as well as genetic constructs carrying viral proteins or information about them, are used as an antigen. However, the viral genome is very evolutionary labile and changes continuously. Second, chemical agents are used during infection and inhibit the function of a number of viral proteins. However, these drugs lose their effectiveness because the virus can rapidly acquire resistance to them. The third is the search for points in the host metabolism the effect on which would suppress the replication of the virus but would not have a significant effect on the metabolism of the host. Here, we consider the possibility of using the copper metabolic system as a target to reduce the severity of influenza infection. This is facilitated by the fact that, in mammals, copper status can be rapidly reduced by silver nanoparticles and restored after their cancellation.

Immunoinflammatory effects of dietary bioactive compounds

Inflammation is a key mechanism of the immune system that can be elicited by several factors, among them several chemical, physical and biological agents. Once stimulated, the inflammatory response activates a series of signaling pathways and a number of immune cells which promote, in a very coordinated manner, the neutralization of the infectious agent. However, if uncontrolled, the inflammatory status may become chronic leading, potentially, to tissue damage and disease onset. Several risk factors are associated with the development of chronic inflammation and, among these factors, diet plays an essential role. In this chapter the effects of some dietary bioactive compounds, including micronutrients, omega-3 fatty acids, nucleotides and polyphenols, on the immunoinflammatory responses in different cellular, animal and human studies have been summarized.

Evidence linking exposure of fish primary macrophages to antibiotics activates the NF-kB pathway

Low doses of antibiotics are ubiquitous in the marine environment and may exert negative effects on non-target aquatic organisms. Using primary macrophages of common carp, we investigated the mechanisms of action following exposure to several common antibiotics; cefotaxime, enrofloxacin, tetracycline, sulfamonomethoxine, and their mixtures, and explored the immunomodulatory effects associated with the nuclear factor-κB (NF-κB) signaling pathway. A KEGG pathway analysis was conducted using the sixty-six differentially expressed genes found in all treatments, and showed that exposure to 100 μg/L of antibiotics could affect regulation of the NF-κB signaling pathway, suggesting that activation of NF-κB is a common response in all four classes of antibiotics. In addition, the four antibiotics induced nf-κb and NF-κB-associated cytokines expression, as verified by qPCR, however, these induction responses by four antibiotics were minor when compared to the same concentration of LPS treatment (100 μg/L). Antagonists of NF-κB blocked many of the immune effects of the antibiotics, providing evidence that NF-κB pathways mediate the actions of all four antibiotics. Moreover, exposure to environmentally relevant, low levels (0.01-100 μg/L) of antibiotics induced a NF-κB-mediated immune response, including endogenous generation of ROS, activity of antioxidant enzymes, as well as expression of cytokine and apoptosis. Moreover, exposure to mixtures of antibiotics presented greater effects on most tested immunological parameters than exposure to a single antibiotic, suggesting additive effects from multiple antibiotics in the environment. This study demonstrates that exposure of fish primary macrophages to low doses of antibiotics activates the NF-kB pathway.

Differential effects of zinc and tellurium on epigenetic changes of coping behaviour in maturing rats

Trace element and its probable role in biological systems have attracted the attention of many researchers in recent years. Previous work has shown that ZnTe administered in drinking water to pregnant rats during pregnancy, delivery, lactation and offspring maturation up to prepuberal stage is able to modify several parameters of spontaneous behaviours related to cognition in offspring rats. Since Zn and Te have many biological properties, it’s not possible to conclude if behavioural changes are due to Zn, Te or both trace elements activity. In the present work, K₂TeO₃ and ZnCl₂ were used alone in order to evaluate single actions of trace elements. Four experimental groups were formed: Control (water), Zn-treated group, Te-treated groups, and Zn+Te group. At the end of the experiments at 30 days of age offspring of each group were tested individually in a Double-Hole Board Labyrinth to evaluate lateralized exploration. Open field enriched with a rack and hole-board to evaluate motivated exploration; single cage in an intruder-host test to evaluate social interaction, and forced swimming cylinder to evaluate the survival responses. Results showed selective changes in rearing for Te (first Test); blocking of the natural left-biased exploration (second Test) increased time to confront the intruder with decreased time to interact with the intruder (third Test), and decreased time to active swimming (fourth Test).

With the exception of duration of the social interaction, Zn has no effect. Results suggest that most of the behavioural changes found with ZnTe in previous studies are due to Te.

Trace element levels are associated with neuroinflammatory markers in children with autistic spectrum disorder

The objective of the present study was to estimate the association between brain inflammatory markers and serum trace element levels as assessed by inductively coupled plasma mass spectrometry at NexION 300D. Leukocyte elastase (LE), α1-proteinase inhibitor (α1-PI) activity, anti-nerve growth factor-antibodies (anti-NGF-Ab), and anti-myelin basic protein-antibodies (anti-MBP-Ab) levels were assessed as inflammatory markers. The obtained data demonstrate that the increase in LE and α1-PI activity is associated with higher serum Cr and Cu levels, respectively. The increase in Anti-NGF-Ab levels was associated with a nearly significant 16% increase in serum Mn levels. Autistic children with high MBP-Ab levels were characterized by 28% higher serum Mn and lower Mg concentration. The results of correlation analysis were generally in agreement with the outcome of group comparisons. Regression analysis demonstrated that serum Mg was significantly negatively associated with LE activity, whereas both serum Fe and V concentrations were characterized by a positive influence on the parameter. In turn, serum Cu was a significant predictor of α1-PI, as well as Cr levels. At the same time, the serum concentrations of Cd and Fe were found to be inversely associated with α1-PI levels. Serum Cd and Mn levels were significant positive predictors of anti-MBP-Ab levels, whereas Mg levels had a negative impact on anti-MBP-Ab values. Generally, the obtained data demonstrate the interrelationship between trace element homeostasis and neuroinflammation in autism. Hypothetically, modulation of trace element status may be used for reduction of neuroinflammatory response, although further studies are required to reveal the underlying mechanisms of the observed associations.

Modulatory effects of new curcumin analogues on gamma-irradiation - Induced nephrotoxicity in rats

In the present study, a new series of 2-amino-pyran-3-carbonitrile derivatives of curcumin 2-7 have been synthesized via one-pot simple and efficient protocol, involving the reaction of curcumin 1 with substituted-benzylidene-malononitrile to modify the 1,3-diketone moiety. The structures of the synthesized compounds 2-7 were elucidated by microanalytical and spectral data, which were found consistent with the assigned structures. The nephroprotective mechanism of these new curcumin analogues was evaluated on the post-gamma-irradiation (7 Gy) - induced nephrotoxicity in rats. Activation of Nrf2 by these curcumin analogues is responsible for the amendment of the antioxidant status, impairment of NF-κB signal, thus attenuate the nephrotoxicity induced post-γ-irradiation exposure. 4-Chloro-phenyl curcumin analogue 7 showed the most potent activity. In conclusion, the results of the present study demonstrate a promising role of these new curcumin analogues to attenuate the early symptoms of nephrotoxicity induced by γ-irradiation in rats via activation of Nrf2 gene expression. These new curcumin analogues need further toxicological investigations to assess their therapeutic index.

The role of the PM2.5-associated metals in pathogenesis of child Mycoplasma Pneumoniae infections: a systematic review

The peak occurrence of Mycoplasma pneumoniae (M. pneumoniae) infections in childhood and haze episodes is concurrent. Together, the prevalence of macrolide-resistant M. pneumoniae varies among countries might also be related to the concentration of ambient fine particulate mass (aerodynamic diameter ≤2.5 μm, PM2.5). Numerous cohort studies have identified consistent associations between ambient PM2.5 and cardiorespiratory morbidity and mortality. PM2.5 is a carrier of the heavy metals. The relationship between PM2.5-associated metals and M. pneumoniae infections in childhood has been increasingly drawing public attention. First, we reviewed original articles and review papers in Pubmed and Web of Science regarding M. pneumoniae and PM2.5-associated metal and analyzed the structural basis of PM2.5-associated metal interaction with M. pneumoniae. Then, the possible mechanisms of action between them were conjectured. Mechanisms of oxidative stress induction and modulation of the host immune system and inflammatory responses via Toll-like receptors (TLRs) and/or the nuclear factor-kappa B (NF-κB) pathway are postulated to be the result of PM2.5-associated metal complex interaction with M. pneumoniae. In addition, a heavy metal effect on M. pneumoniae-expressed community-acquired respiratory distress syndrome (CARDS) toxin, and activation of the aryl hydrocarbon receptor (AhR) and TLRs to induce the differentiation of T helper (Th) cells are also regarded as important reasons for the influence of the heavy metals on the severity of M. pneumoniae pneumonia and the initial onset and exacerbation of M. pneumoniae associated asthma. PM2.5-associated metals via complex mechanisms can exert a great impact on the host through interaction with M. pneumoniae.

Hepatoprotective effect of grape seed oil against carbon tetrachloride induced oxidative stress in liver of γ-irradiated rat

Carbon tetrachloride (CCl4) and ionizing radiation are well known environmental pollutants that generate free radicals and induce oxidative stress. The liver is the primary and major target organ responsible for the metabolism of drugs, toxic chemicals and affected by irradiation. This study investigated the effect of grape seed oil (GSO) on acute liver injury induced by carbon tetrachloride (CCl4) in γ-irradiated rats (7Gy). CCl4-intoxicated rats exhibited an elevation of ALT, AST activities, IL-6 and TNF-α level in the serum. Further, the levels of MDA, NO, NF-κB and the gene expression of CYP2E1, iNOS and Caspase-3 were increased, and SOD, CAT, GSH-Px, GST activities and GSH content were decreased. Furthermore, silent information regulator protein 1 (SIRT1) gene expression was markedly down-regulated. Additionally, alterations of the trace elements; copper, manganese, zinc and DNA fragmentation was observed in the hepatic tissues of the intoxicated group. These effects were augmented in CCl4-intoxicated-γ-irradiated rats. However, the administration of GSO ameliorated these parameters. GSO exhibit protective effects on CCl4 induced acute liver injury in γ-irradiated rats that could be attributed to its potent antioxidant, anti-inflammatory and anti-apoptotic activities. The induction of the antioxidant enzymes activities, down-regulation of the CYP2E1, iNOS, Caspase-3 and NF-κB expression, up-regulation of the trace elements concentration levels and activation of SIRT1 gene expression are responsible for the improvement of the antioxidant and anti-inflammatory status in the hepatic tissues and could be claimed to be the hepatoprotective mechanism of GSO.

Determination of some metal ions in various meat and baby food samples by atomic spectrometry

In this paper, we report a simple and rapid solid phase extraction system for the separation/preconcentration and determination of Cd(II), Co(II), Cu(II), Fe(III), Cr(III), Pb(II), and Zn(II) ions by flame atomic absorption spectrometry (FAAS). This method is based upon the retention of metal ions on a column packed with poly[N-(3-methyl-1H-indole-1-yl)]-2-methacrylamide-co-2-acrylamido-2-methyl-1-propane sulphonic acid-co divinylbenzene] (MMAD) resin as a solid-phase extraction (SPE) sorbent at pH 8. At the optimized conditions, the limits of detection (3 s/b) between 0.12 and 1.6 μg L(-1), preconcentration factor of 100, and the relative standard deviation of ⩽1.8% were achieved (n=10). The accuracy of the method was verified by analyzing certified reference materials (CRMs) and performing recovery experiments. The developed method was successfully applied to the various natural water, meat products and baby food samples. The recoveries of analyte ions were found in added real samples and CRMs from 95% to 102%.

Elevated Lifetime Lead Exposure Impedes Osteoclast Activity and Produces an Increase in Bone Mass in Adolescent Mice

The heavy metal lead (Pb) has a deleterious effect on skeletal health. Because bone mass is maintained through a balance of bone formation and resorption, it is important to understand the effect of Pb levels on osteoblastic and osteoclastic activity. Pb exposure is associated with low bone mass in animal models and human populations; however, the correlation between Pb dosing and corresponding bone mass has been poorly explored. Thus, mice were exposed to increasing Pb and at higher levels (500 ppm), there was unexpectedly an increase in femur-tibial bone mass by 3 months of age. This is contrary to several studies alluded to earlier. Increased bone volume (BV) was accompanied by a significant increase in cortical thickness of the femur and trabecular bone that extended beyond the epiphyseal area into the marrow cavity. Subsequent evaluations revealed an increase in osteoclast numbers with high Pb exposure, but a deficiency in osteoclastic activity. These findings were substantiated by observed increases in levels of the resorption-altering hormones calcitonin and estrogen. In addition we found that pro-osteoclastic nuclear factor-kappa beta (NF-κB) pathway activity was dose dependently elevated with Pb, both in vivo and in vitro. However, the ability of osteoclasts to resorb bone was depressed in the presence of Pb in media and within test bone wafers. These findings indicate that exposure to high Pb levels disrupts early life bone accrual that may involve a disruption of osteoclast activity. This study accentuates the dose dependent variation in Pb exposure and consequent effects on skeletal health.

NF-κB p65 subunit DNA-binding activity: association with depleted antioxidant levels in breast carcinoma patients

NF-κB is recognized as a redox-sensitive transcription factor and has been implicated in cellular response to oxidative stress. The study was designed to correlate the changes in antioxidant status with the levels of nuclear factor-κB (NF-κB) p65 subunit DNA-binding activity in relation to lymph node involvement, tumor size, and staging in breast carcinoma patients. Case control study comprised of 40 breast carcinoma patients along with 40 age- and sex-matched healthy subjects as controls. Levels of enzymatic/nonenzymatic antioxidants along with the trace elements were measured to study the antioxidant status in the study subjects. Levels of NF-κB p65 subunit DNA-binding activity was estimated by ELISA assay. The levels of enzymatic, nonenzymatic antioxidants, and trace elements were found to be significantly depleted in breast carcinoma patients in comparison to healthy controls suggesting significantly decreased levels of antioxidant activity in the breast carcinoma patients. Also, these results indicate that antioxidant levels decrease progressively with the advancement of stage and subsequent progression of disease. DNA-binding activity of NF-κB p65 subunit was higher in breast cancer patients in comparison to normal healthy controls, and the activity was found to increase with the advancement of disease. Significant correlation was observed between the DNA-binding activity of NF-κB p65 subunit and antioxidant status in the patients. The logistic regression analysis revealed decreased levels of antioxidants and increased level of DNA-binding activity of NF-κB p65 subunit were significantly associated with incidence of breast carcinoma. Depleted antioxidant status and increased level of DNA-binding activity of NF-κB p65 subunit thus point clearly of an association in relation to disease progression, clinical stage, and cytological grade in the pathophysiology of breast carcinoma.

Selenium, zinc, and copper plasma levels in patients with schizophrenia: relationship with metabolic risk factors

The aim of this study was to determine the plasma selenium (Se), copper (Cu), and zinc (Zn) levels and to evaluate their possible association with metabolic syndrome (MetS) components in patients with schizophrenia. The study group consisted of 60 patients with schizophrenia and 60 sex- and age-matched healthy controls. Anthropometric measurements, blood pressure, and biochemical analysis of fasting blood were performed in all subjects. Patients with schizophrenia had significantly higher plasma Cu concentrations compared with controls (0.97 ± 0.31 vs. 0.77 ± 0.32 mg/L, p = 0.001). The plasma Cu concentration showed a positive correlation with plasma glucose and diastolic blood pressure in the patient groups (r s = 0.263, p < 0.05 and r s = 0.272, p < 0.05, respectively). The plasma Se level correlated positive with MetS score (r s = 0.385, p < 0.01), waist circumference (r s = 0.344, p < 0.05), plasma glucose (r s = 0.319, p < 0.05), and triglyceride concentrations (r s = 0.462, p < 0.001) in patients with schizophrenia. Plasma Zn did not correlate with any of the MetS components. These results suggest that alterations in plasma Cu and Se levels in medicated patients with schizophrenia could be associated with metabolic risk factors.

[Mineral content of some herbs and plant extracts with anti-inflammatory effect used in gastrointestinal diseases]

INTRODUCTION

In gastrointestinal diseases folk medicine usually recommends herbs and teas with antiinflammatory activities, especially mucilage and bitter agent containing plants. The use of stomatics as adjuvant therapy in medical practice is frequent.

AIM

The authors explored the mineral element content of some herbs, because mineral elements may have significant role in the development and treatment of gastrointestinal diseases, and a close connection between the presence or absence of mineral elements and inflammatory mediators was noted.

METHODS

The mineral content in Trigonellae foenugraeci semen, Farfarae folium et flos, Taraxaci radix and Cichorii radix and teas prepared from these herbs was determined using inductively coupled plasma optical emission spectrometry. The results were evaluated from nutritional and biomedical points of view.

RESULTS

Farfarae folium et flos tea was found to be a rich source of calcium, chromium, manganese and molybdenum. Trigonellae foenugraeci semen, Taraxaci radix and Cichorii radix displayed favourable calcium to magnesium ratio (1-1.5) and they contained other elements (manganese, iron, copper, zinc) which may have significant role in the immune defence system.

CONCLUSION

The beneficial therapeutic effect of the studied herbs may be related to their mineral element content.

Sex-dependent alterations in erythrocyte trace element levels and antioxidant status after a month of moderate daily red wine consumption

OBJECTIVE

We tested the hypothesis whether trace elements and antioxidant status change in a sex-dependent manner may contribute to sex-dependent hepatic effects of moderate daily wine consumption.

PATIENT AND METHODS

Twenty-one healthy young men and women were enrolled to this study who consumed red wine 0.3 and 0.2 l per day, respectively, for a month. Blood was taken at baseline (BV) and at end of the study (EV). Red cell trace element levels, red cell and plasma antioxidant status and serum routine blood chemistry were assessed at baseline and at the end of the study.

RESULTS

No sign of hepatotoxicity was detected. BV level of some trace elements (i.e. Zn, Pb) and Zn/Cu ratios were higher in women than in men. Ca, Mg, Pb, Sr and Zn levels and the Zn/Cu ratio had lower EV than BV in women. In men, Al, Ca, Li, Pb and Sr levels had lower EV than BV. The tested antioxidant parameters improved in both the sexes.

CONCLUSION

Although no hepatotoxicity was observed, changes in trace element content were detected after 1 month of moderate red wine consumption. The most remarkable sex-specific alteration was the decrease of Zn levels and of the Zn/Cu ratio in women. Given the protective effect of Zn against liver damage, this finding suggests a possible contribution of decreased Zn levels to sex-dependent effects of red wine.

Relationship between microstructure, cytotoxicity and corrosion properties of a Cu-Al-Ni shape memory alloy

Cu-Al-Ni shape memory alloys (SMAs) have been investigated as materials for medical devices, but their biomedical application is still limited. The aim of this work was to compare the microstructure, corrosion and cytotoxicity in vitro of a Cu-Al-Ni SMA. Rapidly solidified (RS) thin ribbons, manufactured via melt spinning, were used for the tests. The control alloy was a permanent mould casting of the same composition, but without shape memory effect. The results show that RS ribbons are significantly more resistant to corrosion compared with the control alloy, as judged by the lesser release of Cu and Ni into the conditioning medium. These results correlate with the finding that RS ribbons were not cytotoxic to L929 mouse fibroblasts and rat thymocytes. In addition, the RS ribbon conditioning medium inhibited cellular proliferation and IL-2 production by activated rat splenocytes to a much lesser extent. The inhibitory effects were almost completely abolished by conditioning the RS ribbons in culture medium for 4 weeks. Microstructural analysis showed that RS ribbons are martensitic, with boron particles as a minor phase. In contrast, the control Cu-Al-Ni alloy had a complex multiphase microstructure. Examination of the alloy surfaces after conditioning by energy dispersive X-ray and Auger electron spectroscopy showed the formation of Cu and Al oxide layers and confirmed that the metals in RS ribbons are less susceptible to oxidation and corrosion compared with the control alloy. In conclusion, these results suggest that rapid solidification significantly improves the corrosion stability and biocompatibility in vitro of Cu-Al-Ni SMA ribbons.

The Response of Macrophages to a Cu-Al-Ni Shape Memory Alloy

Cu—Al—Ni shape memory alloys (SMAs) have been investigated as materials for medical devices, but little is known about their biocompatibility. The aim of this work was to study the response of rat peritoneal macrophages (PMØ) to a Cu—Al—Ni SMA in vitro, by measuring the functional activity of mitochondria, necrosis, apoptosis, and production of proinflammatory cytokines. Rapidly solidified (RS) thin ribbons were used for the tests. The control alloy was a permanent mold casting of the same composition, but without the shape memory effect. Our results showed that the control alloy was severely cytotoxic, whereas RS ribbons induced neither necrosis nor apoptosis of PMØ. These findings correlated with the data that RS ribbons are significantly more resistant to corrosion compared to the control alloy, as judged by the lesser release of Cu and Ni in the conditioning medium. However, the ribbons generated intracellular reactive oxygen species and upregulated the production of IL-6 by PMØ. These effects were almost completely abolished by conditioning the RS ribbons for 5 weeks. In conclusion, RS significantly improves the corrosion stability and biocompatibility of Cu—Al—Ni SMA. The biocompatibility of this functional material could be additionally enhanced by conditioning the ribbons in cell culture medium.

Copper modulates the differentiation of mouse hematopoietic progenitor cells in culture

Copper chelation has been shown to favor the expansion of human hematopoietic stem/progenitor cells in vitro. To further understand the effects of copper modulation on defined subsets of stem cells versus progenitor cells, we extended the studies in a mouse system. We isolated mouse hematopoietic stem cells (HSCs) or hematopoietic progenitor cells (HPCs) and cultured them with or without the copper chelator tetraethylenepentamine (TEPA) or CuCl(2). Cytokine-stimulated HPC cultures treated with TEPA for 7 days generated about two to three times more total and erythroid colony-forming cells (CFCs) compared to control cultures. In contrast, CuCl(2) treatment decreased the CFC numbers. Similar results were seen with HSC after 14, but not 7, days of culture. Transplant studies showed that HPCs cultured for 7 days in TEPA had about twofold higher short-term erythroid repopulation potential compared to control cultures, while CuCl(2) decreased the erythroid potential of cultured HPCs compared to control cultures. HSCs cultured with TEPA for 7 days did not exhibit significantly higher repopulation potential in either leukocyte or erythrocyte lineages compared to control cultures in short-term or long-term assays. Based on JC-1 staining, the mitochondrial membrane potential of HPCs cultured with TEPA was lower relative to control cultures. Our data suggest that decreasing the cellular copper content with TEPA results in preferential expansion or maintenance of HPC that are biased for erythroid differentiation in vivo, but does not enhance the maintenance of HSC activity in culture.

From free radicals to science of nutrition

A szabadgyök-kutatás évtizedei alatt egyre közelebb kerültünk ahhoz a felismeréshez, hogy a szervezet szabad gyök–antioxidáns egyensúlyát alapvetően a genetikai háttér és a környezet határozza meg. A Janus-arcú oxigén-szabadgyökök a szignáltranszdukciós utak szekunder hírvivői és egyben a sejtek citotoxikus ágensei is. A szignáltranszdukciós fehérjék mérsékelt oxidációs hatásokra és fémionokra történő aktivációja még nem eléggé ismert. A szignáltranszdukció aktivátorai és inhibitorai közötti molekuláris mechanizmusok finoman kontrolláltak. A sejtek antioxidáns–prooxidáns egyensúlya visszavezethető a szabad szulfhidrilcsoportok és a diszulfidhidak koncentrációviszonyára. Az esszenciális és toxikus fémionok, valamint a szelén egyaránt szerepet játszanak a redox-homeosztázisban. Az egészséges szövetek bővelkednek antioxidánsokban, ezáltal biztosítják a szervezet szabad gyökökkel szembeni védelmét. A táplálékkal felvett antioxidáns vegyületek, mint például az A-, C-, E-vitaminok, polifenolok, antocianinok, flavonoidok, izotiocianátok és más bioaktív molekulák eredeti molekulaformájukban és derivátumaikban is képesek befolyásolni a redoxifolyamatokat. Napjaink molekuláris biológai kutatásainak eredményeképpen egyre több, táplálékkal felvehető vegyületről, illetve azok metabolitjairól bizonyosodik be, hogy génszinten is kifejtik hatásukat.

Extreme consumption of Beta vulgaris var. rubra can cause metal ion accumulation in the liver

Redox homeostasis can be considered as the cumulative action of all free radical reactions and antioxidant defences in different tissues, which provide suitable conditions for life. Transition metal ions are ubiquitous in biological systems. Beta vulgaris var. rubra (table beet root) contains several bioactive agents (e.g. betain, betanin, vulgaxanthine, polyphenols, folic acid) and different metal elements (e.g. Al, B, Ba, Ca, Cu, Fe, K, Mg, Mn, Na, Zn), which act on the various physiological routes. Therefore we studied the effect of this metal rich vegetable on element content of the liver in healthy rats. Male Wistar rats (n = 7) (200 +/- 20 g) were treated with lyophilised powder of table beet root (2 g/kg b.w.) added into the rat chow for 10 days. Five healthy animals served as control. We found significant accumulation of Cu, Fe, Mg, Mn, Zn and P in the liver, which was proved by ICP-AES measurements. We suppose that the extreme consumption of table beet root can cause several disturbances not only in cases of healthy patients but, e.g. in patients suffering with metal accumulating diseases, e.g. porphyria cutanea tarda, haemochromatosis or Wilson disease-although moderate consumption may be beneficial in iron-deficiency anaemia and inflammatory bowel diseases.

Differential expression of genes involved with apoptosis, cell cycle, connective tissue proteins, fuel substrate utilization, inflammation and mitochondrial biogenesis in copper-deficient rat hearts: implication of a role for Nfkappab1

We hypothesized that the increase in mitochondrial proliferation in hearts from copper-deficient rats is due to an increase in expression of the transcriptional factor peroxisomal-like proliferating related coactivator 1alpha (Ppargc1a), which regulates transcriptional activity for many of the genes that encode for mitochondrial proteins. In addition to several transcriptional factors implicated in mitochondrial biogenesis, we also looked at a number of genes involved in cell cycle regulation and fuel substrate utilization. Long-Evans rats were placed on either a copper-adequate (n=4) or copper-deficient (n=4) diet 3 days post weaning and remained on the diet for 5 weeks; their copper deficiency status was confirmed using previously established assays. Custom oligo arrays spotted with genes pertinent to mitochondrial biogenesis were hybridized with cRNA probes synthesized from the collected heart tissue. Chemiluminescent array images from both groups were analyzed for gene spot intensities and differential gene expression. Our results did not demonstrate any significant increase in Ppargc1a or its implicated targets, as we had predicted. However, consistent with previous data, an up-regulation of genes that encode for collagen type 3, fibronectin and elastin were found. Interestingly, there was also a significant increase in the expression of the transcriptional factor nuclear factor kappaB1 (Nfkappab1) in the copper-deficient treatment animals, compared to the control group, and this was confirmed by real time quantitative polymerase chain reaction. The results of this study merit the further investigation of the role of reactive oxidative species with regard to Nfkappab1 in the copper deficient rat heart.

Is zinc deficiency a risk factor for atherosclerosis?

The development of atherosclerosis is influenced by genetic, lifestyle and nutritional risk factors. Zn and metallothionein deficiency can enhance oxidative-stress-related signalling processes in endothelial cells, and since changes in available plasma Zn may affect the Zn status of the endothelium, Zn deficiency could be a risk factor for IHD. Although the association of Zn with many proteins is essential for their function, three key signalling processes are highlighted as being principal targets for the effect of Zn deficiency: the activation of NF-κB, the activation of caspase enzymes and the signalling of NO. The need to develop a reliable indicator of Zn status is critical to any epidemiological approach for studying the relationship between Zn status and disease incidence. Studies using appropriate animal models and investigating how the plasma Zn pool influences endothelial intracellular labile Zn would be helpful in appreciating the importance of Zn deficiency in atherogenesis.

Gold-induced reactive oxygen species (ROS) do not mediate suppression of monocytic mitochondrial or secretory function

The toxicity of anti-rheumatic gold compounds has limited their use and development, yet both the toxicological and therapeutic actions of these compounds remain unclear. In the current study, we tested the hypothesis that intracellular reactive oxygen species (ROS) induced by Au(I) or Au(III) compounds mediate their ability to suppress mitochondrial activity.

METHODS

Human THP1 monocytes were exposed to HAuCl(4) x 3H(2)O (Au(III)), or the anti-rheumatic compounds auranofin (AF) or gold sodium thiomalate (GSTM) for 6-72 h, after which mitochondrial activity (succinate dehydrogenase) was measured. To assess the role of cellular redox status as a mediator of mitochondrial suppression, monocytes were pre-treated with a pro-oxidant (t-butyl hydroquinone, t-BHQ) or antioxidant (N-acetyl cysteine, NAC ). ROS levels were measured 0-24h post-gold addition to determine their role as mediators of mitochondrial activity suppression.

RESULTS

AF was the most potent inhibitor of mitochondrial activity, followed by Au(III) and GSTM. Only Au(III) induced intracellular ROS; no ROS formation was observed in response to AF or GSTM exposure. Although anti- and pro-oxidants had some effects on mitochondrial suppression of Au compounds, collectively the data do not support redox effects or ROS formation as major mediators of Au-compound mitochondrial suppression.

CONCLUSIONS

Our results do not indicate that ROS and redox effects play major roles in mediating the cytotoxicity of AF, GSTM or Au(III).

Effects of select PM-associated metals on alveolar macrophage phosphorylated ERK1 and -2 and iNOS expression during ongoing alteration in iron homeostasis

It was hypothesized that relative mass relationships among select constituent metals and iron (Fe3+) govern the pulmonary immunotoxic potential of any PM(2.5) sample, as these determine the extent to which Fe3+ binding by transferrin is affected (resulting in altered alveolar macrophage [AM] Fe status and subsequent antibacterial function). Iron response protein (IRP) binding activity is a useful indirect measurement of changes in Fe status, as reductions in cell Fe levels lead to increases in IRP binding. However, AM IRP activity can be affected by an increased presence of nitric oxide generated by inducible nitric oxide synthase (iNOS). This study sought to determine if any changes in AM IRP activity induced by PM(2.5) constituents V, Mn, or Al were independent from effects of the metals on cell NO formation. NR8383 rat AM were exposed to Fe3+ alone or combined with V, Mn, or Al at metal:Fe ratios representative of those in PM(2.5) collected in New York City, Los Angeles, and Seattle during fall 2001. Cells were then assessed for changes in IRP activity and iNOS expression. Phosphorylated extracellular signal-regulated kinase (ERK) 1 and 2 levels were also measured since activated ERKs are involved in signaling pathways that lead to increased iNOS expression. The results indicate that V and Al, and to a lesser extent Mn, altered IRP activity, though the effects were not consistently concentration dependent. Furthermore, while V and Mn treatments did not induce iNOS expression, Al did. These results confirmed our hypothesis that certain metals associated with PM(2.5) might alter the pulmonary immunocompetence of exposed hosts by affecting the Fe status of AM, a major class of deep lung defense cells.

Early histological and functional effects of chronic copper exposure in rat liver

Cu is an essential trace element capable of producing toxic effects in animals and man when ingested acutely or chronically in excess. Although chronic Cu exposure is increasingly recognized as a public health issue, its early effects remain largely unknown. We approached the significance of a moderate chronic Cu load in young rats to correlate early hepatic histopathological changes with functional alterations of liver cells. For this purpose, supplementation with 1,200 ppm of Cu in rat food for 16 weeks was chosen. In these conditions, Cu load elicited a significant decrease in growth curves. There were mild light microscopy alterations in Cu-treated rats, although increasing intracellular Cu storage was correlated with longer Cu exposure both by histological and biochemical measurements. Ultrastructural alterations included lysosomal inclusions as well as mitochondrial and nuclear changes. Liver perfusion studies revealed higher rates of basal O(2) consumption and colloidal carbon-induced O(2) uptake in Cu-treated rats, with enhanced carbon-induced O(2)/carbon uptake ratios and NF-kappaB DNA binding activity. These changes were time-dependent and returned to control values after 12 or 16 weeks. It is concluded that subchronic Cu loading in young rats induces early hepatic morphological changes, with enhancement in Küpffer cell-dependent respiratory burst activity and NF-kappaB DNA binding, cellular responses that may prevent or alleviate the hepatotoxicity of the metal.

Chelatable cellular copper modulates differentiation and self-renewal of cord blood-derived hematopoietic progenitor cells

OBJECTIVES

We have demonstrated epigenetic modulation of CD34(+) cell differentiation by the high-affinity copper (Cu) chelator tetraethylenepentamine (TEPA). TEPA slowed down the rate of CD34(+) cell differentiation and increased their engraftability in SCID mice. TEPA biological activity was attributed to its effect on cellular Cu levels as (a) treatment with TEPA resulted in reduction of cellular Cu, and (b) excess of Cu reversed TEPA's activity and accelerated differentiation. In the present study we further evaluated the role of cellular Cu in TEPA's biological activity.

METHODS

The effects of Cu-chloride, TEPA, TEPA/Cu mixtures at various ratios, and a synthesized, stable, TEPA-Cu complex on short- and long-term cord blood-derived CD34(+) cell cultures as well as on the overall and chelatable cellular Cu were investigated.

RESULTS

Addition of TEPA, TEPA/Cu mixtures at up to equimolar concentrations, and the TEPA-Cu complex to CD34(+) cell cultures resulted in inhibition of differentiation and enhancement of long-term self-renewal. Measurement of the overall cellular Cu by atomic absorption spectrophotometry showed 20 to 40% decrease by TEPA while the TEPA-Cu mixture and the TEPA-Cu complex increased cellular Cu by 10- to 20-fold, as did CuCl(2). However, measurement of the cellular pool of labile Cu showed similar reduction (50% from the control) by all the TEPA forms, while CuCl(2) increased it. Thus, inhibition of differentiation and enhancement of self-renewal of CD34(+) cells was correlated with reduction in the cellular chelatable Cu content.

CONCLUSION

The results suggest that decreasing of the chelatable Cu pool, rather than overall Cu, is the mechanism that stands behind TEPA's biological activity.

Monocyte viability on titanium and copper coated titanium

The role of apoptosis/cell death in the inflammatory response at the implanted materials is unexplored. Two surfaces with different cytotoxic potential and in vivo outcomes, titanium (Ti) and copper (Cu) were incubated in vitro with human monocytes and studied using a method to discriminate apoptotic and necrotic cells (Annexin V/PI staining). Further, staurosporine, a potent inducer of apoptosis, was added to the surface adherent monocytes. Lactate dehydrogenase (a marker of cell membrane injury) and TNF-alpha and IL-10, cytokines, previously suggested to play a major role in the monocyte apoptosis, were assayed in the culture medium. The results demonstrated that Ti surfaces displayed enhanced monocyte survival and production of IL-10 and TNF-alpha. Cu adherent cells exhibited apoptotic signs as early as 1h after incubation. In contrast to Ti, after 48 h the predominance of apoptotic cells switched to apoptotic/necrotic cells on Cu surfaces. Staurosporine treatment of Ti adherent cells mediated similar type of cell death. LDH and cytokine contents were low around Cu surfaces, partly explained by interference between Cu ions and LDH and cytokines. This study suggests that material properties rapidly influence the onset of human monocyte apoptosis and progression to late apoptosis/necrosis. Early detection of apoptosis and cell death may be important for the understanding of the biological response to implanted materials.

In vivo cytokine secretion and NF-kappaB activation around titanium and copper implants

The early biological response at titanium (Ti), copper (Cu)-coated Ti and sham sites was evaluated in an in vivo rat model. Material surface chemical and topographical properties were characterized using Auger electron spectroscopy, energy dispersive X-ray spectroscopy and interferometry, respectively. The number of leukocytes, cell types and cell viability (release of lactate dehydrogenase) were determined in the implant-interface exudate. The contents of activated nuclear transcription factor NF-kappaB, interleukin-6 (IL-6) and interleukin-10 (IL-10) were determined by enzyme linked immunosorbent assay. An increase in the number of leukocytes, in particular, polymorphonuclear leukocytes, was observed between 12 and 48 h around Cu. A marked decrease of exudate cell viability was found around Cu after 48 h. The total amounts of activated NF-kappaB after 12 h was highest in Ti exudates whereas after 48 h the highest amount of NF-kappaB was detected around Cu. The levels of cytokine IL-6 were consistently high around Cu at both time periods. No differences in IL-10 contents were detected, irrespective of material/sham and time. The results show that materials with different toxicity grades (titanium with low and copper with high toxicity) exhibit early differences in the activation of NF-kappaB, extracellular expression and secretion of mediators, causing major differences in inflammatory cell accumulation and death in vivo.

Au(III), Pd(II), Ni(II), and Hg(II) alter NFκB signaling in THP1 monocytic cells

The transcription factor NFkappaB plays a key role in the tissue inflammatory response. Metal ions released into tissues from biomaterials (e.g., Au, Pd, Ni, Hg) are known to alter the binding of NFkappaB proteins to DNA, thereby modulating the effect of NFkappaB on gene activation and, ultimately, the tissue response to biomaterials. Little is known about the effect of these metals on key signaling steps prior to NFkappaB-DNA binding such as transcription factor activation or nuclear translocation, yet these steps are equally important to modulation of the pathway. Oxidative stress is known to alter NFkappaB proteins and is suspected to play a role in metal-induced NFkappaB signaling modulation. Our aim in the current study was to assess the effects of sublethal levels of Ni, Hg, Pd, and Au ions on NFkappaB activation and nuclear translocation in the monocyte, which is acknowledged as an important orchestrator of the biological response to materials and the pathogenesis of chronic disease. Sublethal concentrations of Au(III), Ni(II), Hg(II), and Pd(II) were added to cultures of human THP1 monocytic cells for 72 h. In parallel cultures, lipopolysaccharide (LPS) was added for the last 30 min to activate the monocytic cells. Then cellular cytoplasmic and nuclear proteins were isolated, separated by electrophoresis, and probed for IkappaBalpha degradation (activation) and NFkappaB p65 translocation. Protein levels were digitally quantified and statistically compared. The levels of reactive oxygen species (ROS) in the monocytic cells were measured as a possible mechanism of metal-induced NFkappaB modulation. Only Au(III) activated IkappaBalpha degradation by itself. Au(III) and Pd(II) enhanced LPS-induced IkappaBalpha degradation, but Hg(II) and Ni(II) suppressed it. Au(III), Ni(II), and Pd(II) activated p65 nuclear translocation without LPS, and all but Ni(II) enhanced LPS-induced translocation. Collectively, the results suggest that these metal ions alter activation and translocation of NFkappaB, each in a unique way at unique concentrations. Furthermore, even when these metals had no overt effects on signaling by themselves, all altered activation of signaling by LPS, suggesting that the biological effects of these metals on monocytic function may only be manifest upon activation. None of the metal ions elevated levels of ROS at 72 h, indicating that ROS were probably not direct modulators of the NFkappaB activation or translocation at this late time point.

Signal transduction pathways relevant for neoplastic effects of fibrous and non-fibrous particles

Apart from their genotoxic effects, both fibrous and non-fibrous particles are known to induce signalling pathways involved in the development of malignant lung diseases. Different direct effects of particles as well as indirect cellular effects are believed to induce changes in apoptosis or proliferation in target cells. Signalling events, e.g. the induction of mitogen-activated protein kinase (MAPK) cascades resulting in the activation of the transcription factor AP-1, as well as the induction of the transcription factor NFkappaB which mainly mediates the expression of pro-inflammatory genes are discussed. There is some insight into the molecular mechanisms eliciting these pathways. Therefore, this review aims to give an overview on signalling pathways as well as initial events including effects of reactive oxygen and nitrogen species, membrane receptors and particle uptake.

Future directions in bonding resins to the dentine-pulp complex

Resin-based materials are rapidly becoming the primary restorative material to replace tooth structure and the low percentage of biological problems reported for resin-based restorations is testimony to their relative biocompatibility. Despite considerable advances in the understanding of the mechanisms, which govern the integration of resin composite materials with the dentine-pulp complex, considerable potential for improvement remains. Most of these improvements centre around a better understanding of the biological and microbiological risks of resin materials and will only be possible with improved in vitro and in vivo models. There are also a number of possible future developments in materials, clinical techniques and diagnostic methods that may improve the long-term success and reliability of resin-based restorations. The remainder of this paper describes the most likely avenues for future improvements.

Hepatic metallothionein in patients with chronic hepatitis C: relationship with severity of liver disease and response to treatment

OBJECTIVES

Reactive oxygen species may be involved in the pathogenesis of chronic hepatitis C virus infection. Metallothionein (MT) is an essential protein for the protection of cells against reactive oxygen species. The aim of this prospective study was to assess the influence of the hepatic level and cellular distribution of MT in hepatitis C virus (HCV) infection and in the liver disease outcome.

METHODS

In liver biopsy samples of 32 patients with chronic HCV infection and of 12 control subjects, quantification of MT was performed by radioimmunoassay, MT, interleukin (IL)-1 and -6, and tumor necrosis factor (INF)-alpha mRNA by reverse transcription-polymerase chain reaction (PCR) and cellular distribution by immunohistochemistry.

RESULTS

In HCV-infected patients, MT liver protein level was 3-fold lower than in control specimens. A significant inverse linear regression between MT protein or mRNA expression and the Histological Activity Index, the necroinflammatory grade, and the stage of fibrosis was observed. MT immunostaining was located in the nucleus and cytoplasm in hepatocytes of control subjects, whereas it was mainly cytoplasmic in HCV-infected patients. Before interferon (IFN) therapy, the hepatic MT level in patients that were nonsustained responders was half that of sustained responders. Intrahepatic IL-6 and MT were simultaneously down-regulated, but no correlation was found between MT and intrahepatic cytokine mRNA expression in patients with chronic HCV infection.

CONCLUSIONS

This study shows that hepatic MT expression could reflect the severity of chronic HCV infection and could be one of the factors associated with a favorable clinical outcome in the response to interferon therapy.

Metal ions alter lipopolysaccharide-induced NFκB binding in monocytes

Metals are components of a variety of biomaterials used in orthopedic and dental appliances; however, their biocompatibility with the surrounding tissues is not completely understood. Monocytes are important immune cells that respond to inflammatory stimuli by rapidly producing a variety of inflammatory proteins. Regulation of this response often involves activation of the transcription factor NF kappa B. The current study was designed to determine whether monocyte activation of NF kappa B in response to bacterial lipopolysaccharide (LPS) is affected by pretreatment with metal ions. Concentrations of metal ions that affected cell number after 24 h of exposure were first determined. Then THP-1 human monocytes were cultured for 2 h in media containing metal ions at concentrations below levels that altered cell growth. Parallel cultures were treated with 10 microg/mL Escherichia coli LPS, and all samples were cultured an additional 2 h. Nuclear proteins were extracted and normalized amounts were incubated with [(32)P]-end-labeled NF kappa B consensus oligonucleotide. NF kappa B-DNA complexes were identified and quantified by electrophoretic mobility shift analysis. The extent of NF kappa B-DNA complex formation after metal ion pretreatment with or without LPS induction was compared to no treatment or LPS-only treated controls. Finally, LPS-induced IL1 beta secretion was measured from palladium-treated and control cells. Concentrations were identified for each metal ion (Ag(+), Co(2+), Cu(2+), Hg(2+), Ni(2+), and Pd(2+)) that did not reduce cell number after 24 h of exposure (ranging from 5 microM for Ag(+) and Hg(2+) to 200 microM for Ni(2+)). Exposures of 2 h at these concentrations did not alter cell morphology, staining with trypan blue, or cell number. LPS exposure had no effect on cell number with or without metal ions after 2 h. When metal treatment alone was assessed, none of the metal ions had a significant effect on NF kappa B-DNA binding. However, pretreatment with Co(2+), Ni(2+), Ag(1+), Hg(2+), and Pd(2+) significantly decreased NF kappa B-DNA binding by 40-70% versus LPS alone. Only Cu(2+) had no effect on LPS-induced NF kappa B-DNA complex formation. Pd(2+) lowered, but did not abolish, IL1 beta secretion at concentrations comparable to those that altered NF kappa B-DNA binding. These results suggest that many commonly used metals alter monocyte function at concentrations that are not overtly toxic, and that protein levels controlled in part by NF kappa B also may be altered.

Lead alters parathyroid hormone-related peptide and transforming growth factor-beta1 effects and AP-1 and NF-kappaB signaling in chondrocytes

The skeletal system is an important target for lead toxicity. One of the impacts of lead in the skeleton, the inhibition of axial bone development, is likely due to its effect on the normal progression of chondrocyte maturation that is central to the process of endochondral ossification. Since little is known about the effect of lead on chondrocyte function/maturation, its impact on (1) growth factor-induced proliferation, (2) expression of maturation-specific markers type X collagen and BMP-6, and (3) the activity of AP-1 and NF-kappaB was examined in chick growth plate and sternal chondrocyte models. Exposure to lead alone (1-30 microM) resulted in a dose-dependent inhibition of thymidine incorporation in growth plate chondrocytes. Lead also blunted the stimulation of thymidine incorporation by parathyroid hormone-related peptide (PTHrP) and transforming growth factor-beta1 (TGF-beta1), two critical regulators of chondrocyte maturation. Lead (1 and 10 microM), TGF-beta1 (3 ng/ml) and PTHrP (10(-7) M) all significantly inhibited the expression of type X collagen, a marker of chondrocyte terminal differentiation. However, when in combination, lead completely reversed the inhibition of type X collagen by PTHrP and TGF-beta1. The effect of lead on BMP-6. an inducer of terminal differentiation. was also examined. Independently, lead and TGF-beta1 were without effect on BMP-6 expression, but PTHrP significantly suppressed it. Comparatively, lead did not alter PTHrP-mediated suppression of BMP-6, but in combination with TGF-beta1. BMP-6 expression was increased 3-fold. To determine if lead effects on signaling might play a role in facilitating these events, the impact of lead on NF-kappaB and AP-1 signaling was assessed using luciferase reporter constructs in sternal chondrocytes. Lead had no effect on the AP-1 reporter, but it dose-dependently inhibited the NF-kappaB reporter. PTHrP, which signals through AP-1, did not activate the NF-kappaB reporter and did not affect inhibition of this reporter by lead. In contrast, PTHrP activation of the AP-1 reporter was dose-dependently enhanced by lead. These findings, which establish that chondrocytes are important targets for lead toxicity, suggest that the effects of lead on bone growth are derived from its impact on the modulation of chondrocyte maturation by growth factors and second messenger signaling responses.

Cellular copper content modulates differentiation and self-renewal in cultures of cord blood-derived CD34+ cells

Several clinical observations have suggested that copper (Cu) plays a role in regulating haematopoietic progenitor cell (HPC) development. To further study this role we used an ex vivo system. Cord blood-derived CD34+ cells were cultured in liquid medium supplemented with Kit- ligand, FLt3, interleukin 6 (IL-6), thrombopoietin and IL-3. Under these conditions, Cu content, measured by atomic absorption, was 7 ng/10(7) cells. Modulation of intracellular Cu was achieved by supplementing the cultures with the Cu chelator tetraethylenepentamine, which reduced cellular Cu (4 ng/10(7) cells), or ceruloplasmin or Cu sulphate that elevated cellular Cu (18 and 14 ng/10(7) cells respectively). The results indicated that low Cu content delayed differentiation, as measured by the surface antigens CD34, CD14 and CD15, colony-forming unit (CFU) frequency and cell morphology, while high Cu accelerated differentiation compared with Cu unmanipulated cultures. As a result, expansion of total cells, CFU and CD34+ cells in low Cu was extended (12-16 weeks), and in high Cu was shortened (2-4 weeks), compared with control cultures (6-8 weeks). These effects required modulation of intracellular Cu only during the first 1-3 weeks of the culture; the long-term effects persisted thereafter, suggesting that the decision process for either self-renewal or differentiation is taken early during the culture. This novel method of controlling cell proliferation and differentiation by copper and copper chelators might be utilized for ex vivo manipulation of HPC for various clinical applications.