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Signaling circuits crucial to systemic physiology are widespread, yet uncovering their molecular underpinnings remains a barrier to understanding the etiology of many metabolic disorders. Here, we identified a copper-linked signaling circuit activated by disruption of mitochondrial function in the murine liver or heart that resulted in atrophy of the spleen and thymus and caused a peripheral white blood cell deficiency. We demonstrated that the leukopenia was caused by a-fetoprotein, which required copper and the cell surface receptor CCR5 to promote white blood cell death. We further showed that a-fetoprotein expression was upregulated in several cell types upon inhibition of oxidative phosphorylation. Collectively, our data argue that a-fetoprotein may be secreted by bioenergetically stressed tissue to suppress the immune system, an effect that may explain the recurrent or chronic infections that are observed in a subset of mitochondrial diseases or in other disorders with secondary mitochondrial dysfunction., Introduction To maintain homeostasis, tissue and organ systems must adapt in unison to varying metabolic challenges (1). These responses involve a cell autonomous component that acts locally at the affected [...]

Wilson disease (WD) is caused by mutations in the ATP7B gene that encodes a copper (Cu) transporting ATPase whose trafficking from the Golgi to endo‐lysosomal compartments drives sequestration of excess Cu and its further excretion from hepatocytes into the bile. Loss of ATP7B function leads to toxic Cu overload in the liver and subsequently in the brain, causing fatal hepatic and neurological abnormalities. The limitations of existing WD therapies call for the development of new therapeutic approaches, which require an amenable animal model system for screening and validation of drugs and molecular targets. To achieve this objective, we generated a mutant Caenorhabditis elegans strain with a substitution of a conserved histidine (H828Q) in the ATP7B ortholog cua‐1 corresponding to the most common ATP7B variant (H1069Q) that causes WD. cua‐1 mutant animals exhibited very poor resistance to Cu compared to the wild‐type strain. This manifested in a strong delay in larval development, a shorter lifespan, impaired motility, oxidative stress pathway activation, and mitochondrial damage. In addition, morphological analysis revealed several neuronal abnormalities in cua‐1 mutant animals exposed to Cu. Further investigation suggested that mutant CUA‐1 is retained and degraded in the endoplasmic reticulum, similarly to human ATP7B‐H1069Q. As a consequence, the mutant protein does not allow animals to counteract Cu toxicity. Notably, pharmacological correctors of ATP7B‐H1069Q reduced Cu toxicity in cua‐1 mutants indicating that similar pathogenic molecular pathways might be activated by the H/Q substitution and, therefore, targeted for rescue of ATP7B/CUA‐1 function. Taken together, our findings suggest that the newly generated cua‐1 mutant strain represents an excellent model for Cu toxicity studies in WD. [ABSTRACT FROM AUTHOR]

In this study we examine the effect of the phytoestrogen genistein on DNA methylation. DNA methylation is thought to inhibit transcription of genes by regulating alterations in chromatin structure. Estrogenic compounds have been reported to regulate DNA methylation in a small number of studies. Additionally, phytoestrogens are believed to affect progression of some human diseases, such as estrogen-dependent cancers, osteoporosis and cardiovascular disease. Specifically, our working hypothesis is that certain soy phytoestrogens, such as genistein, may be involved in preventing the development of certain prostate and mammary cancers by maintaining a protective DNA methylation profile. The objective of the present study is to use mouse differential methylation hybridization (DMH) arrays to test for changes in the methylation status of the cytosine guanine dinucleotide (CpG) islands in the mouse genome by examining how these methylation patterns are affected by genistein. Male mice were fed a casein-based diet (control) or the same diet containing 300 mg genistein/kg according to one of four regimens: control diet for 4 wk, genistein diet for 4 wk, control diet for 2 wk followed by genistein diet for 2. wk and genistein diet for 2 wk followed by control diet for 2 wk. DNA from liver, brain and prostate were then screened with DMH arrays. Clones with methylation differences were sequenced and compared with known sequences. In conclusion, consumption of genistein diet was positively correlated with changes in prostate DNA methylation at CpG islands of specific mouse genes. KEY WORDS: * genistein * phytoestrogen * DNA methylation

Copper (Cu) is essential for development and proliferation, yet the cellular requirements for Cu in these processes are not well defined. We report that Cu plays an unanticipated role in the mitogen-activated protein (MAP) kinase pathway. Ablation of the Ctr1 high-affinity Cu transporter in flies and mouse cells, mutation of Ctr1, and Cu chelators all reduce the ability of the MAP kinase kinase Mek1 to phosphorylate the MAP kinase Erk. Moreover, mice bearing a cardiac-tissue-specific knockout of Ctr1 are deficient in Erk phosphorylation in cardiac tissue. in vitro investigations reveal that recombinant Mek1 binds two Cu atoms with high affinity and that Cu enhances Mek1 phosphorylation of Erk in a dose-dependent fashion. Coimmunoprecipitation experiments suggest that Cu is important for promoting the Mek1-Erk physical interaction that precedes the phosphorylation of Erk by Mek1. These results demonstrate a role for Ctr1 and Cu in activating a pathway well known to play a key role in normal physiology and in cancer. [ABSTRACT FROM AUTHOR]

The mouse mZip1 and mZip3 zinc transporters have been implicated in zinc acquisition by the cells of many tissues. This hypothesis raised the question of whether activity of these proteins is regulated to maintain zinc homeostasis. Neither mZIP1 nor mZIP3 mRNA levels are highly regulated by zinc status. Therefore, we investigated whether zinc controls the activity of these proteins post-translationally by altering their subcellular distribution. When expressed in transfected cells grown in zinc-replete medium, both mZip1 and mZip3 were largely present in intracellular organelles. However, these proteins were found to rapidly transit between the plasma membrane and intracellular compartments in zinc-replete cells. Zinc deficiency increased plasma membrane levels of mZip1 and mZip3 by decreasing their rates of endocytosis. Greater zinc deficiency was required to alter mZip3 distribution than was needed to affect mZip1. Increased surface levels correlated with increased zinc uptake activity. Taken together, these results suggest that post-translational control of mZip1 and mZip3 localization plays a role in zinc homeostasis. Moreover, our results indicate that zinc-responsive endocytosis is a conserved mechanism controlling activity of many mammalian zinc uptake transporters. [ABSTRACT FROM AUTHOR]

Copper (Cu) is an essential trace element for key biochemical reactions. Dietary or genetic copper deficiencies are associated with anemia, cardiomyopathy, and neurodegeneration. The essential requirement for copper in humans is illustrated by Menkes disease, a fatal neurodegenerative disorder of early childhood caused by mutations in the ATP7A copper transporter. Recent groundbreaking studies have demonstrated that a copper delivery small molecule compound, elesclomol (ES), is able to substantially ameliorate pathology and lethality in a mouse model of Menkes disease when injected as an ES-Cu 2+ complex. It is well appreciated that drugs administered through oral means are more convenient with better efficacy than injection methods. Here we show, using genetic models of copper-deficient C. elegans and mice, that dietary ES supplementation fully rescues copper deficiency phenotypes. Worms lacking either the homolog of the CTR1 copper importer or the ATP7 copper exporter showed normal development when fed ES. Oral gavage with ES rescued intestine-specific Ctr1 knockout mice from early postnatal lethality without additional copper supplementation. Our findings reveal that ES facilitates copper delivery from dietary sources independent of the intestinal copper transporter CTR1 and provide insight into oral administration of ES as an optimal therapeutic for Menkes disease and possibly other disorders of copper insufficiency., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Yuan, Korolnek and Kim.)

SCO1 is a ubiquitously expressed, mitochondrial protein with essential roles in cytochrome c oxidase (COX) assembly and the regulation of copper homeostasis. SCO1 patients present with severe forms of early onset disease, and ultimately succumb from liver, heart or brain failure. However, the inherent susceptibility of these tissues to SCO1 mutations and the clinical heterogeneity observed across SCO1 pedigrees remain poorly understood phenomena. To further address this issue, we generated Sco1hrt/hrt and Sco1stm/stm mice in which Sco1 was specifically deleted in heart and striated muscle, respectively. Lethality was observed in both models due to a combined COX and copper deficiency that resulted in a dilated cardiomyopathy. Left ventricular dilation and loss of heart function was preceded by a temporal decrease in COX activity and copper levels in the longer-lived Sco1stm/stm mice. Interestingly, the reduction in copper content of Sco1stm/stm cardiomyocytes was due to the mislocalisation of CTR1, the high affinity transporter that imports copper into the cell. CTR1 was similarly mislocalized to the cytosol in the heart of knockin mice carrying a homozygous G115S substitution in Sco1, which in humans causes a hypertrophic cardiomyopathy. Our current findings in the heart are in marked contrast to our prior observations in the liver, where Sco1 deletion results in a near complete absence of CTR1 protein. These data collectively argue that mutations perturbing SCO1 function have tissue-specific consequences for the machinery that ultimately governs copper homeostasis, and further establish the importance of aberrant mitochondrial signaling to the etiology of copper handling disorders., (© The Author 2017. Published by Oxford University Press.)

Copper (Cu) is an essential cofactor for various enzymatic activities including mitochondrial electron transport, iron mobilization, and peptide hormone maturation. Consequently, Cu dysregulation is associated with fatal neonatal disease, liver and cardiac dysfunction, and anemia. While the Cu transporter ATP7A plays a major role in both intestinal Cu mobilization to the periphery and prevention of Cu over-accumulation, it is unclear how regulation of ATP7A contributes to Cu homeostasis in response to systemic Cu fluctuation. Here we show, using Cu-deficient mouse models, that steady-state levels of ATP7A are lower in peripheral tissues (including the heart, spleen, and liver) under Cu deficiency and that subcutaneous administration of Cu to these animals restore normal ATP7A levels in these tissues. Strikingly, ATP7A in the intestine is regulated in the opposite manner - low systemic Cu increases ATP7A while subcutaneous Cu administration decreases ATP7A suggesting that intestine-specific non-autonomous regulation of ATP7A abundance may serve as a key homeostatic control for Cu export into the circulation. Our results support a systemic model for how a single transporter can be inversely regulated in a tissue-specific manner to maintain organismal Cu homeostasis.

Copper is an essential catalytic cofactor for enzymatic activities that drive a range of metabolic biochemistry including mitochondrial electron transport, iron mobilization, and peptide hormone maturation. Copper dysregulation is associated with fatal infantile disease, liver, and cardiac dysfunction, neuropathy, and anemia. Here we report that mammals regulate systemic copper acquisition and intracellular mobilization via cleavage of the copper-binding ecto-domain of the copper transporter 1 (Ctr1). Although full-length Ctr1 is critical to drive efficient copper import across the plasma membrane, cleavage of the ecto-domain is required for Ctr1 to mobilize endosomal copper stores. The biogenesis of the truncated form of Ctr1 requires the structurally related, previously enigmatic copper transporter 2 (Ctr2). Ctr2(-/-) mice are defective in accumulation of truncated Ctr1 and exhibit increased tissue copper levels, and X-ray fluorescence microscopy demonstrates that copper accumulates as intracellular foci. These studies identify a key regulatory mechanism for mammalian copper transport through Ctr2-dependent accumulation of a Ctr1 variant lacking the copper- and cisplatin-binding ecto-domain.

Copper (Cu) is a redox-active metal ion essential for most aerobic organisms. Cu serves as a catalytic and structural cofactor for enzymes that function in energy generation, iron acquisition, oxygen transport, cellular metabolism, peptide hormone maturation, blood clotting, signal transduction and a host of other processes. The inability to control Cu balance is associated with genetic diseases of overload and deficiency and has recently been tied to neurodegenerative disorders and fungal virulence. The essential nature of Cu, the existence of human genetic disorders of Cu metabolism and the potential impact of Cu deposition in the environment have been driving forces for detailed investigations in microbial and eukaryotic model systems. Here we review recent advances in the identification and function of cellular and systemic molecules that drive Cu accumulation, distribution and sensing.