Cu loading alters expression of non-IRE regulated, but not IRE regulated, Fe dependent proteins in HepG2 cells

Copper Exposure Induced Chicken Hepatotoxicity: Involvement of Ferroptosis Mediated by Lipid Peroxidation, Ferritinophagy, and Inhibition of FSP1-CoQ10 and Nrf2/SLC7A11/GPX4 Axis

Copper (Cu) is one of the most significant trace elements in the body, but it is also a widespread environmental toxicant health. Ferroptosis is a newly identified programmed cell death, which involves various heavy metal-induced organ toxicity. Nevertheless, the role of ferroptosis in Cu-induced hepatotoxicity remains poorly understood. In this study, we found that 330 mg/kg Cu could disrupt the liver structure and cause characteristic morphological changes in mitochondria associated with ferroptosis. Additionally, Cu treatment increased MDA (malondialdehyde) and LPO (lipid peroxide) production while reducing GSH (reduced glutathione) content and GCL (glutamate cysteine ligase) activity. However, it is noticeable that there were no appreciable differences in liver iron content and key indicators of iron metabolism. Meanwhile, our further investigation found that 330 mg/kg Cu-exposure changed multiple ferroptosis-related indicators in chicken livers, including inhibition of the expression of SLC7A11, GPX4, FSP1, and COQ10B, whereas enhances the levels of ACLS4, LPCAT3, and LOXHD1. Furthermore, the changes in the expression of NCOA4, TXNIP, and Nrf2/Keap1 signaling pathway-related genes and proteins also further confirmed 330 mg/kg Cu exposure-induced ferroptosis. In conclusion, our results indicated that ferroptosis may play essential roles in Cu overload-induced liver damage, which offered new insights into the pathogenesis of Cu-induced hepatotoxicity.

Interplay of Ferritin Accumulation and Ferroportin Loss in Ageing Brain: Implication for Protein Aggregation in Down Syndrome Dementia, Alzheimer’s, and Parkinson’s Diseases

Iron accumulates in the ageing brain and in brains with neurodegenerative diseases such as Alzheimer’s disease (AD), Parkinson’s disease (PD), Huntington’s disease (HD), and Down syndrome (DS) dementia. However, the mechanisms of iron deposition and regional selectivity in the brain are ill-understood. The identification of several proteins that are involved in iron homeostasis, transport, and regulation suggests avenues to explore their function in neurodegenerative diseases. To uncover the molecular mechanisms underlying this association, we investigated the distribution and expression of these key iron proteins in brain tissues of patients with AD, DS, PD, and compared them with age-matched controls. Ferritin is an iron storage protein that is deposited in senile plaques in the AD and DS brain, as well as in neuromelanin-containing neurons in the Lewy bodies in PD brain. The transporter of ferrous iron, Divalent metal protein 1 (DMT1), was observed solely in the capillary endothelium and in astrocytes close to the ventricles with unchanged expression in PD. The principal iron transporter, ferroportin, is strikingly reduced in the AD brain compared to age-matched controls. Extensive blood vessel damage in the basal ganglia and deposition of punctate ferritin heavy chain (FTH) and hepcidin were found in the caudate and putamen within striosomes/matrix in both PD and DS brains. We suggest that downregulation of ferroportin could be a key reason for iron mismanagement through disruption of cellular entry and exit pathways of the endothelium. Membrane damage and subsequent impairment of ferroportin and hepcidin causes oxidative stress that contributes to neurodegeneration seen in DS, AD, and in PD subjects. We further propose that a lack of ferritin contributes to neurodegeneration as a consequence of failure to export toxic metals from the cortex in AD/DS and from the substantia nigra and caudate/putamen in PD brain.

Study of Metal-Metal Interactions and Their Biomarkers Using an Intestinal Human Cell Line

From the time of dietary intake to their utilization, the number of important interactions occurs among mineral elements, which can affect their bioavailability because of similarity in physicochemical properties and common absorptive pathways. However, the studies that have analyzed the interactions among copper, iron, and zinc have conflicting results and need further exploration. HT-29 cells grown to confluence in 6-well plates were incubated with increasing concentrations (0 to 200 μM) of Cu, Fe, and Zn for 3 and 6 h for uptake studies. Interaction studies involved measuring the uptake of metal in the presence of 0:1-4:1 ratio of the other metal for 3 h using atomic absorption spectrophotometer. The concentration of metal biomarkers and cytokines was also measured in the cell lysate following extracellular supplementation. The presence of 50 μM Zn significantly decreased (P < 0.05) cellular Cu uptake in HT-29 cells at 0.5:1 Cu:Zn ratio and also the cellular Fe uptake at the ratios 0.5:1, 2:1, and 4:1 Fe:Zn. The presence of 50 μM Fe significantly (P < 0.05) decreased cellular Cu uptake at the ratios 1:1, 2:1, and 4:1 Cu:Fe. The concentration of metallothionein responded significantly (P < 0.05) to changes in extracellular Zn concentration (supplementation and depletion). There was a decrease in concentration of IL-1β and TNF-α (P < 0.05) with an increasing extracellular concentration of Cu and Fe. The results of the study indicated that the presence of one mineral in the diet and multi mineral supplement may influence the bioavailability of the other mineral. Copper and iron may find application in promoting gut health.

Ceruloplasmin is regulated by copper and lactational hormones in PMC42-LA mammary epithelial cell culture models

Ceruloplasmin (Cp) is a multicopper ferroxidase that is considered to be an important source of copper in milk for normal neonatal development. We investigated the expression, subcellular localization and secretion of Cp in PMC42-LA cell culture models representative of resting, lactating and suckled human mammary epithelia. Both secreted Cp (sCp) and plasma membrane associated glycosylphosphatidylinositol-linked Cp (GPI-Cp) were expressed in PMC42-LA cells. In all three epithelial models (resting, lactating and suckled), the expression and secretion of copper-bound, ferroxidase active, Cp (holo-Cp) was dependent on media copper concentration. In low copper (bathocuproinedisulphonic acid/d-penicillamine treated models) there was greater than a 2-fold decrease in holo-Cp expression and secretion, which was mirrored by a 2-fold increase in the expression and secretion of copper-free Cp protein (apo-Cp). Cell surface biotinylation studies revealed that the state of PMC42-LA cell differentiation (functionality), and the level of extracellular copper, had no significant effect on the level of plasma membrane bound GPI-Cp. Quantitative real time PCR analyses determined that there was no significant (P > 0.05) difference in Cp mRNA levels across all copper conditions investigated (0, 5, 50 μM). However, there was a significant (P < 0.05) increase (∼2-fold) in Cp mRNA in both the lactating and suckled models in comparison to the resting model. Furthermore, the Cp mRNA increase in response to PMC42-LA differentiation corresponded with more secreted Cp protein, both apo and holo forms, indicating a link between function and Cp requirement. Our results provide significant insight on the regulation of Cp expression and secretion in lactation and copper incorporation into milk.

The Early Nutrition Programming Project (EARNEST): 5 y of successful multidisciplinary collaborative research

Differences in nutritional experiences during sensitive periods in early life, both before and after birth, can program a person's future development, metabolism, and health. A better scientific understanding of early nutrition programming holds enormous potential for implementing preventive strategies to enhance individuals' long-term health, well-being, and performance. This understanding could reduce costs of health care and social services and may enhance the wealth of societies. The Early Nutrition Programming Project (EARNEST) brought together a multidisciplinary team of international scientists and leaders in key areas of the early nutrition programming field from 40 major research centers across 16 European countries. The project had a total budget of 16.5 million Euros and was funded by the European Communities under the Sixth Framework Program for Research and Technical Development and coordinated by the Children's Hospital at Ludwig-Maximilians-University of Munich. The integrated program of work combined experimental studies in humans, prospective observational studies, and mechanistic animal work, including physiologic studies, cell culture models, and molecular biology techniques. The project lasted from April 2005 to October 2010. After the end of the project, the Early Nutrition Academy (http://www.early-nutrition.org) continues to serve as a platform for the exchange of information, scientific collaboration, and training activities in the area of programming. This article highlights some of the scientific results, achievements, and efforts of EARNEST.

Serum ceruloplasmin protein expression and activity increases in iron-deficient rats and is further enhanced by higher dietary copper intake

Increases in serum and liver copper content are noted during iron deficiency in mammals, suggesting that copper-dependent processes participate during iron deprivation. One point of intersection between the 2 metals is the liver-derived, multicopper ferroxidase ceruloplasmin (Cp) that is important for iron release from certain tissues. The current study sought to explore Cp expression and activity during physiologic states in which hepatic copper loading occurs (eg, iron deficiency). Weanling rats were fed control or low iron diets containing low, normal, or high copper for ∼ 5 weeks, and parameters of iron homeostasis were measured. Liver copper increased in control and iron-deficient rats fed extra copper. Hepatic Cp mRNA levels did not change; however, serum Cp protein was higher during iron deprivation and with higher copper consumption. In-gel and spectrophotometric ferroxidase and amine oxidase assays demonstrated that Cp activity was enhanced when hepatic copper loading occurred. Interestingly, liver copper levels strongly correlated with Cp protein expression and activity. These observations support the possibility that liver copper loading increases metallation of the Cp protein, leading to increased production of the holo enzyme. Moreover, this phenomenon may play an important role in the compensatory response to maintain iron homeostasis during iron deficiency.

Novel Cu(II)-RGD-octapeptides: Synthesis, coordination mode, in vitro anti-platelet aggregation/in vivo anti-thrombotic evaluation and correlation of sequence with nano-structure

The synthesis, bioassays and nano-structure characterization of Cu(II)-RGD-octapeptide complexes Cu(II)-Arg-Gly-Asp-Ser-Arg-Gly-Asp-Ser [Cu(II)-4a], Cu(II)-Arg-Gly-Asp-Val-Arg-Gly-Asp-Val [Cu(II)-4b] and Cu(II)-Arg-Gly-Asp-Phe-Arg-Gly-Asp-Phe [Cu(II)-4c] were investigated. UV-vis, CD and CD/ESI-MS spectra suggested that the coordination of Cu(II)-4a-c met a 3 N mode. In the in vitro anti-platelet aggregation assay the IC(50) values of Cu(II)-RGD-octapeptide complexes were 10 - 110 folds lower than that of RGD-octapeptides. In the in vivo anti-thrombotic assay the effective dose of Cu(II)-RGD-octapeptide complexes was 5000 folds lower than that of RGD-octapeptides. In transmission electron microscopy measurement Cu(II)-4a-c offered distinct nano-images. The effect of the sequence on the in vitro anti-platelet aggregation/in vivo anti-thrombotic activity and the nano-structure of Cu(II)-4a-c was discussed.

FROM THE CLINICAL EDITOR

This basic science paper discusses the synthesis, coordination mode, in vitro anti-platelet aggregation and in vivo anti-thrombotic evaluation of novel Cu(II)-RGD-octapeptides.

The relationship between dietary supplement use in late pregnancy and birth outcomes: a cohort study in British women

Objective

To examine the relationship between dietary supplement use during pregnancy and birth outcomes.

Design

A prospective birth cohort.

Setting

Leeds, UK.

Sample

One thousand two hundred and seventy-four pregnant women aged 18–45 years.

Methods

Dietary supplement intake was ascertained using three questionnaires for the first, second and third trimesters. Dietary intake was reported in a 24-hour dietary recall administered by a research midwife at 8–12 weeks of gestation. Information on delivery details and antenatal pregnancy complications was obtained from the hospital maternity records.

Main outcome measures

Birthweight, birth centile and preterm birth.

Results

Reported dietary supplement use declined from 82% of women in the first trimester of pregnancy to 22% in the second trimester and 33% in the third trimester. Folic acid was the most commonly reported supplement taken. Taking any type of daily supplement during any trimester was not significantly associated with size at birth taking into account known relevant confounders. Women taking multivitamin-mineral supplements in the third trimester were more likely to experience preterm birth (adjusted OR = 3.4, 95% CI 1.2, 9.6, P= 0.02).

Conclusions

Regular multivitamin–mineral supplement use during pregnancy, in a developed country setting, is not associated with size at birth. However, it appears to be associated with preterm birth if taken daily in the third trimester. The mechanism for this is unclear and our study’s findings need confirming by other cohorts and/or trials in developed countries.