Copper Metabolism MURR1 Domain-containing 1 Research Articles

Disruption of COMMD1 accelerates diabetic atherosclerosis by promoting glycolysis.

Diabetes will lead to serious complications, of which atherosclerosis is the most dangerous. This study aimed to explore the mechanisms of diabetic atherosclerosis. ApoE-/- mice were fed with an high-fat diet diet and injected with streptozotocin to establish an in vivo diabetic atherosclerotic model. RAW 264.7 cells were treated with oxidized low-density lipoprotein particles (ox-LDL) and high glucose to produce an in vitro diabetic atherosclerotic model. In this study, we showed that diabetes promoted the progression of atherosclerosis in ApoE-/- mice and that high glucose potentiates macrophage proinflammatory activation and foam cell formation. Mechanistically, Copper metabolism MURR1 domain-containing 1(COMMD1) deficiency increased proinflammatory activation and foam cell formation, characterized by increased glycolysis, and then accelerated the process of atherosclerosis. Furthermore, 2-Deoxy-D-glucose (2-DG) reversed this effect. Taken together, we provided evidence that the lack of COMMD1 accelerates diabetic atherosclerosis via mediating the metabolic reprogramming of macrophages. Our study provides evidence of a protective role for COMMD1 and establishes COMMD1 as a potential therapeutic strategy in patients with diabetic atherosclerosis.

Identification of COMMD1 as a novel lamin A binding partner.

Lamin A, which is encoded by the LMNA gene, regulates gene expression and genome stability through interactions with a variety of proteins. Mutations in LMNA lead to a diverse set of inherited human diseases, collectively referred to as laminopathies. To gain insight into the protein interactions of lamin A, a yeast two-hybrid screen was conducted using the carboxy-terminus of lamin A. The screen identified copper metabolism MURR1 domain-containing 1 (COMMD1) as a novel lamin A binding partner. Colocalization experiments using fluorescent confocal microscopy revealed that COMMD1 colocalized with lamin A in 293 cells. Furthermore, the COMMD1-lamin A protein interaction was also demonstrated in co-immunoprecipitation experiments. Collectively, the present study demonstrated a physical interaction between COMMD1 and lamin A, which may aid to elucidate the mechanisms of lamin A in the aging process.

Transcriptional regulation of HIV-1 host factor COMMD1 by the Sp family.

Copper metabolism Murr1 domain containing1 (COMMD1) has multiple functions in the regulation of protein stability at the plasma membrane and in the cytoplasm. However, the regulation of COMMD1 transcriptional has remained to be elucidated. In the present study, the 5'‑flanking region (‑1,192/+83bp) of the human COMMD1 gene was cloned. It was observed that the COMMD1 promoter region contains GC‑rich region that has 7putative Sp1‑binding sites via insilico analysis. The proximal promoter region at ‑289/+83bp was required for COMMD1 basal promoter activity by deletion constructs of COMMD1 promoter. Moreover, Sp1 inhibitor, mithramycinA, suppressed basal COMMD1 promoter activity. The Sp1‑binding site (‑11/‑1bp) in the proximal promoter region was a critical site for COMMD1 gene regulation by Sp1 and Sp3. Sp1 upregulated COMMD1 promoter activity, whereas Sp3 suppressed it. Endogenous Sp1 and Sp3 bound to the proximal promoter region of COMMD1. Taken together, Sp1 constitutively regulates the basal expression of the COMMD1 gene in human epithelial cell lines.

A novel nuclear complex of DRR1, F-actin and COMMD1 involved in NF-κB degradation and cell growth suppression in neuroblastoma.

Downregulated in renal cell carcinoma 1 (DRR1) has important roles in tumor cell growth, neuron survival and spine formation, and was recently shown to bind actin. However, the roles of nuclear DRR1 remain largely unexplored. Here, we identified an interaction between filamentous actin (F-actin) and DRR1 in the nucleus, and demonstrated that copper metabolism MURR1 domain-containing 1 (COMMD1) is another binding partner of DRR1. Accordingly, DRR1, F-actin and COMMD1 were shown to form a complex in the nucleus, and the stability of COMMD1 was enhanced in this complex. Increased nuclear COMMD1 in turn promoted the degradation of NF-κB. In addition, DRR1 and COMMD1 suppressed the cyclin D1 expression, G1/S transition and cell proliferation of neuroblastoma cells. The binding between DRR1 and F-actin in the nucleus was required for these events. Consistent with these facts, low expressions of DRR1 were associated with tumorigenesis of human neuroblastoma and its mouse model. This study has thus revealed a novel nuclear complex of F-actin, DRR1 and COMMD1 that is involved in NF-κB degradation and cell cycle suppression in neuroblastoma cells.

Transcriptome analysis of copper homeostasis genes reveals coordinated upregulation of SLC31A1,SCO1, and COX11 in colorectal cancer

Copper homeostasis and distribution is strictly regulated by a network of transporters and intracellular chaperones encoded by a group of genes collectively known as copper homeostasis genes (CHGs). In this work, analysis of The Cancer Genome Atlas database for somatic point mutations in colorectal cancer revealed that inactivating mutations are absent or extremely rare in CHGs. Using oligonucleotide microarrays, we found a strong increase in mRNA levels of the membrane copper transporter 1 protein [CTR1; encoded by the solute carrier family 31 member 1 gene (SLC31A1 gene)] in our series of colorectal carcinoma samples. CTR1 is the main copper influx transporter and changes in its expression are able to induce modifications of cellular copper accumulation. The increased SLC31A1 mRNA level is accompanied by a parallel increase in transcript levels for copper efflux pump ATP7A, copper metabolism Murr1 domain containing 1 (COMMD1), the cytochrome C oxidase assembly factors [synthesis of cytochrome c oxidase 1 (SCO1) and cytochrome c oxidase copper chaperone 11 (COX11)], the cupric reductase six transmembrane epithelial antigen of the prostate (STEAP3), and the metal‐regulatory transcription factors (MTF1, MTF2) and specificity protein 1 (SP1). The significant correlation between SLC31A1,SCO1, and COX11 mRNA levels suggests that this transcriptional upregulation might be part of a coordinated program of gene regulation. Transcript‐level upregulation of SLC31A1,SCO1, and COX11 was also confirmed by the analysis of different colon carcinoma cell lines (Caco‐2, HT116, HT29) and cancer cell lines of different tissue origin (MCF7, PC3). Finally, exon‐level expression analysis of SLC31A1 reveals differential expression of alternative transcripts in colorectal cancer and normal colonic mucosa.

Control of NF‐κB activity, inflammation and stemness properties in cancer cells by Copper Metabolism (Murr1) Domain‐Containing 1

It has been shown that persistant activation of NF‐κB in cancer cells contributes to inflammation, expansion of tumor‐initiating cancer stem‐like cells (CSCs), and tumor progression. In contrast, NF‐κB activation in CSCs can elevate expression and release of pro‐inflammatory mediators into the tumor microenvironment and further increase stemness and inflammatory conditions in cancer cells. Nevertheless, the underlying molecular controls are still ill‐defined. In this study, we used bioinformatic analysis to show the upregulation of NF‐kB‐target pro‐inflammatory gene and downregulation of Copper Metabolism (Murr1) Domain‐containing 1 (COMMD1) during the enrichment of stemness of SAS, an oral cancer cell line in tumor sphere culture. The 3′‐UTR of COMMD1 mRNA consists of miR‐205 target site. Parallel studies with SAS and non–small‐cell lung cancer cells, H460 and D121 indicated that miR‐205 reduces COMMD1 expression and the expression of miR‐205 was upregulated upon NF‐kB activation. COMMD1 effectively restrained inflammatory stimuli‐induced NF‐κB activation, cytokine production, as well as leukocytes migration. The lentiviral shRNA‐mediated knockdown of COMMD1 increased the expression of stemness genes, sphere‐forming capacity, and potential for anchorage‐independent growth in cancer cells. Moreover, study with cancer animal model showed that COMMD1 knockdown enhances tumorigenesis and tumor growth, as well as expanded population of CD11b+ tumor‐associated leukocytes and CD117+ stemness‐enriched cancer cells. These results suggest that the miR‐205‐COMMD1‐NF‐κB axis forming a positive feedback loop for amplifying inflammatory and stemness‐associated properties of cancer cells that further promote pro‐inflammatory tumor microenvironment.

Downregulation of COMMD1 by miR-205 promotes a positive feedback loop for amplifying inflammatory- and stemness-associated properties of cancer cells.

Sustained activation of nuclear factor-κB (NF-κB) in cancer cells has been shown to promote inflammation, expansion of cancer stem cell (CSC) population, and tumor development. In contrast, recent studies reveal that CSCs exhibit increased inflammation due to constitutive NF-κB activation; however, the underlying molecular mechanism remains unclear. In the present study, the analysis of microarray data revealed upregulation of NF-κB-regulated pro-inflammatory genes and downregulation of copper metabolism MURR1 domain-containing 1 (COMMD1) during the enrichment for stemness in SAS head and neck squamous-cell carcinoma (HNSCC) cells. The 3′-UTR of COMMD1 mRNA contains microRNA (miR)-205 target site. Parallel studies with HNSCC and NSCLC cells indicated that miR-205 is upregulated upon NF-κB activation and suppresses COMMD1 expression in stemness-enriched cancer cells. COMMD1 negatively regulates the inflammatory responses induced by TLR agonists, IL-1β, and TNF-α by targeting RelA for degradation. The shRNA-mediated downregulation of COMMD1 in cancer cells enhanced inflammatory response, generating favorable conditions for macrophage recruitment. In addition, genes associated with stemness were also upregulated in these cells, which exhibited increased potential for anchorage-independent growth. Furthermore, COMMD1 downregulation promoted in vivo tumorigenesis and tumor growth, and tumors derived from COMMD1-knockdown cells displayed elevated level of NF-κB activation, increased expression of inflammatory- and stemness-associated genes, and contain expanded population of tumor-associated leukocytes and stemness-enriched cancer cells. These results suggest that COMMD1 downregulation by miR-205 promotes tumor development by modulating a positive feedback loop that amplifies inflammatory- and stemness-associated properties of cancer cells.

A cell-type-specific role for murine Commd1 in liver inflammation

The transcription factor NF-κB plays a critical role in the inflammatory response and it has been implicated in various diseases, including non-alcoholic fatty liver disease (NAFLD). Although transient NF-κB activation may protect tissues from stress, a prolonged NF-κB activation can have a detrimental effect on tissue homeostasis and therefore accurate termination is crucial. Copper Metabolism MURR1 Domain-containing 1 (COMMD1), a protein with functions in multiple pathways, has been shown to suppress NF-κB activity. However, its action in controlling liver inflammation has not yet been investigated. To determine the cell-type-specific contribution of Commd1 to liver inflammation, we used hepatocyte and myeloid-specific Commd1-deficient mice. We also used a mouse model of NAFLD to study low-grade chronic liver inflammation: we fed the mice a high fat, high cholesterol (HFC) diet, which results in hepatic lipid accumulation accompanied by liver inflammation. Depletion of hepatocyte Commd1 resulted in elevated levels of the NF-κB transactivation subunit p65 (RelA) but, surprisingly, the level of liver inflammation was not aggravated. In contrast, deficiency of myeloid Commd1 exacerbated diet-induced liver inflammation. Unexpectedly we observed that hepatic and myeloid Commd1 deficiency in the mice both augmented hepatic lipid accumulation. The elevated levels of proinflammatory cytokines in myeloid Commd1-deficient mice might be responsible for the increased level of steatosis. This increase was not seen in hepatocyte Commd1-deficient mice, in which increased lipid accumulation appeared to be independent of inflammation. Our mouse models demonstrate a cell-type-specific role for Commd1 in suppressing liver inflammation and in the progression of NAFLD.

COMMD1 regulates inflammation and colitis-associated cancer progression

NF-κB is a master transcriptional regulator of inflammation that plays an important role in oncogenesis, particularly in tumors that arise in the context of inflammation. Copper metabolism MURR1 domain-containing 1 (COMMD1) is a negative regulator of NF-κB. Recent genetic-based studies in both mice and human patients indicate that COMMD1 has an important role in controlling intestinal inflammation and constraining progression to colitis-associated cancer.

Copper Metabolism Domain-Containing 1 Represses Genes That Promote Inflammation and Protects Mice From Colitis and Colitis-Associated Cancer

Activation of the transcription factor nuclear factor-κB (NF-κB) has been associated with the development of inflammatory bowel disease (IBD). Copper metabolism MURR1 domain containing 1 (COMMD1), a regulator of various transport pathways, has been shown to limit NF-κB activation. We investigated the roles of COMMD1 in the pathogenesis of colitis in mice and IBD in human beings. We created mice with a specific disruption of Commd1 in myeloid cells (Mye-knockout [K/O] mice); we analyzed immune cell populations and functions and expression of genes regulated by NF-κB. Sepsis was induced in Mye-K/O and wild-type mice by cecal ligation and puncture or intraperitoneal injection of lipopolysaccharide (LPS), colitis was induced by administration of dextran sodium sulfate, and colitis-associated cancer was induced by administration of dextran sodium sulfate and azoxymethane. We measured levels of COMMD1 messenger RNA in colon biopsy specimens from 29 patients with IBD and 16 patients without (controls), and validated findings in an independent cohort (17 patients with IBD and 22 controls). We searched for polymorphisms in or near COMMD1 that were associated with IBD using data from the International IBD Genetics Consortium and performed quantitative trait locus analysis. In comparing gene expression patterns between myeloid cells from Mye-K/O and wild-type mice, we found that COMMD1 represses expression of genes induced by LPS. Mye-K/O mice had more intense inflammatory responses to LPS and developed more severe sepsis and colitis, with greater mortality. More Mye-K/O mice with colitis developed colon dysplasia and tumors than wild-type mice. We observed a reduced expression of COMMD1 in colon biopsy specimens and circulating leukocytes from patients with IBD. We associated single-nucleotide variants near COMMD1 with reduced expression of the gene and linked them with increased risk for ulcerative colitis. Expression of COMMD1 bymyeloid cells has anti-inflammatory effects. Reduced expression or function of COMMD1 could be involved in the pathogenesis of IBD.

CCDC22 deficiency in humans blunts activation of proinflammatory NF-κB signaling

NF-κB is a master regulator of inflammation and has been implicated in the pathogenesis of immune disorders and cancer. Its regulation involves a variety of steps, including the controlled degradation of inhibitory IκB proteins. In addition, the inactivation of DNA-bound NF-κB is essential for its regulation. This step requires a factor known as copper metabolism Murr1 domain-containing 1 (COMMD1), the prototype member of a conserved gene family. While COMMD proteins have been linked to the ubiquitination pathway, little else is known about other family members. Here we demonstrate that all COMMD proteins bind to CCDC22, a factor recently implicated in X-linked intellectual disability (XLID). We showed that an XLID-associated CCDC22 mutation decreased CCDC22 protein expression and impaired its binding to COMMD proteins. Moreover, some affected individuals displayed ectodermal dysplasia, a congenital condition that can result from developmental NF-κB blockade. Indeed, patient-derived cells demonstrated impaired NF-κB activation due to decreased IκB ubiquitination and degradation. In addition, we found that COMMD8 acted in conjunction with CCDC22 to direct the degradation of IκB proteins. Taken together, our results indicate that CCDC22 participates in NF-κB activation and that its deficiency leads to decreased IκB turnover in humans, highlighting an important regulatory component of this pathway.

SHORT COMMUNICATION: Functional consequences of RNA interference targeting COMMD1 in a canine hepatic cell line in relation to copper toxicosis

SummaryA deletion in the copper metabolism (Murr1) domain containing 1 (COMMD1) gene is associated with hepatic copper toxicosis in dogs, yet evidence of copper retention in COMMD1‐depleted hepatic cells has not been shown. In a dog hepatic cell line, we analysed the copper metabolic functions after an 80% (mRNA and protein) COMMD1 reduction with COMMD1‐targeting siRNAs. Exposure to 64Cu resulted in a significant increase in copper retention in COMMD1‐depleted cells. COMMD1‐depleted cells were almost three times more sensitive to high extracellular copper concentrations. Copper‐mediated regulation of metallothionein gene expression was enhanced in COMMD1‐depleted cells. Based on the increased copper accumulation and enhanced cellular copper responses upon COMMD1 reduction, we conclude that COMMD1 has a major regulatory function for intracellular copper levels in hepatic cells.