The protease DDI2 regulates NRF1 activation in response to cadmium toxicity

Cardiac Metallothionein Synthesis in Streptozotocin-Induced Diabetic Mice, and Its Protection against Diabetes-Induced Cardiac Injury

In Vivo Expression of Metallothionein in Rat Alveolar Macrophages and Type II Epithelial Cells Following Repeated Cadmium Aerosol Exposures

Effects and cell signaling mechanism of glutamine on rat cardiomyocytes intervened with serum from burned rat

Evaluation of perfluoroalkyl acid activity using primary mouse and human hepatocytes

To investigate metallothionein (MT) expression in pterygium, pinguecula and normal conjunctiva and define its possible significance in this area of the eye. In order to further elucidate the mechanism of MT expression we correlated it with lymphocyte subpopulations (T4, T8), macrophages (CD68), Langerhans' cells (S100) and the proliferation-associated indices (PCNA, Ki67). Eighty-five surgically excised pterygia, 15 pingueculae and 20 normal conjunctivae were immunohistochemically studied by the avidin-biotin (ABC) method. A monoclonal antibody (E9) against a conserved epitope of I and II isoforms of MT was used on formalin-fixed, paraffin-embedded tissues. Statistical analysis was performed using the SPSS statistical package. Epithelial MT expression was detected in all 120 cases examined and in most of them both nuclear and cytoplasmic immunoreactivity was present. Nevertheless no statistically significant difference of MT expression was found between the three types of tissue. A statistically significant positive correlation between MT expression and lymphocyte subsets, macrophages and Langerhans' cells was found in pterygium. On the contrary, we did not find any statistical correlation in pinguecula and normal conjunctiva. In all three types of tissues MT expression was also positively correlated with the proliferation-associated indices. The data suggest that there is immunohistochemically demonstrable MT expression in the epithelium of pterygium, but also of normal conjunctiva and pinguecula. MT may serve a photoprotective role in this region. In pterygium in particular, the biochemical pathway of MT synthesis seems interestingly to cross the pathways of cell proliferation, inflammation and immune activation.

This study aimed to determine the levels of placental cadmium (PCd) and cord blood cadmium (CBCd) and the resulting expression of placental metallothionein (MT) in neonates and to investigate cadmium (Cd) exposure levels in neonates and mothers who live in Guiyu, China, an electronic waste (e-waste) pollution site. Among the 423 mothers included in the study from 2004/2005 to 2007, 289 lived in Guiyu (exposed group) and 134 lived in Chaonan, located 10 km away from Guiyu (controls) and had never been exposed to e-waste pollution. CBCd and PCd levels were measured by atomic absorption spectrometry. Placental MT was examined by immunohistochemistry. Information on maternal and neonatal characteristics and exposure conditions was obtained from hospital records and by personal interviews. For the 3 years, the median CBCd was higher for Guiyu neonates than for controls (3.61 vs. 1.25 μg/L), with 25.61% of Guiyu subjects exhibiting a median CBCd that exceeded the safety limit defined by the World Health Organization (5 μg/L), as compared with 14.18% of control neonates (p < 0.01). In Guiyu, the mean PCd was higher than that for controls (0.17 ± 0.48 vs. 0.10 ± 0.11 μg/g, p ≤ 0.01). The high levels of CBCd and PCd were significantly associated with parents' occupational and environmental exposure to e-waste recycling pollutants. Staining for MT was positive and dense for 67.00% (67/100) of Guiyu neonates as compared with 32.69% (17/52) of controls (p < 0.01). Exposure to e-waste recycling pollutants increased Cd exposure in neonates, which was accompanied by increased placental MT expression.

Downregulated expression of metallothionein and its clinicopathological significance in hepatocellular carcinoma

Immunohistochemical Expression of Metallothionein in Benign Premalignant and Malignant Epithelium of the Larynx: Correlation with p53 and Proliferative Cell Nuclear Antigen

Metallothionein (MT) has been used extensively as a potential molecular biomarker to detect heavy metal pollution in aquatic organisms. In order to investigate the modulation effect of heavy metals and to establish suitable biomarkers for the monitoring of heavy metal pollution, Pelteobagrus fulvidraco metallothionein gene was characterized as the first report in the family Bagridae. Pf-MT transcript was detected at high levels in liver, gonad, kidney, and brain compared to other tissues. A time-course study in response to waterborne Cd (5ppm) revealed that a significant increase in the Pf-MT transcript abundance was observed at 6h in gill, kidney, and liver. These elevated levels were kept for 96h, implying that Cd distributed fast into different organs and was involved in the tissue-specific induction pattern. We observed a significant Pf-MT transcript increase in liver tissues at 48h, followed by gill at 12h and intestine at 48h after Cd exposure. This indicates hepatic MT expression as a potential biomarker of acute Cd exposure in this species. Cd-binding ability of recombinant Pf-MT protein provided evidence for sensitivity to Cd and other heavy metal exposure. In the case of Zn exposure (1ppm), a significant increase in Pf-MT transcript abundance was observed at 12h, and a peak induction level reaching sixfold at 24h was kept until 48h, showing similar transcript induction patterns with Cd. A high level of Pf-MT mRNA after exposure to Cu (1ppm) was observed at 12h that gradually increased until 96h with a 12-fold induction, revealing a long-lasting induction and somewhat dissimilar pattern compared to other metals in liver. Our results demonstrate that Pf-MT can be induced by heavy metals in a tissue-specific and metal-specific manner and plays probably a conserved role in metal detoxification. This study provides new information on P. fulvidraco metallothionein gene for the use of biomarkers indicating metal pollution in fish.

MMP-13 Plays a Role in Keratinocyte Migration, Angiogenesis, and Contraction in Mouse Skin Wound Healing

BackgroundStudies in mice have shown that PPARα is an important regulator of hepatic lipid metabolism and the acute phase response. However, little information is available on the role of PPARα in human liver. Here we set out to compare the function of PPARα in mouse and human hepatocytes via analysis of target gene regulation.Methodology/Principal FindingsPrimary hepatocytes from 6 human and 6 mouse donors were treated with PPARα agonist Wy14643 and gene expression profiling was performed using Affymetrix GeneChips followed by a systems biology analysis. Baseline PPARα expression was similar in human and mouse hepatocytes. Depending on species and time of exposure, Wy14643 significantly induced the expression of 362–672 genes. Surprisingly minor overlap was observed between the Wy14643-regulated genes from mouse and human, although more substantial overlap was observed at the pathway level. Xenobiotics metabolism and apolipoprotein synthesis were specifically regulated by PPARα in human hepatocytes, whereas glycolysis-gluconeogenesis was regulated specifically in mouse hepatocytes. Most of the genes commonly regulated in mouse and human were involved in lipid metabolism and many represented known PPARα targets, including CPT1A, HMGCS2, FABP1, ACSL1, and ADFP. Several genes were identified that were specifically induced by PPARα in human (MBL2, ALAS1, CYP1A1, TSKU) or mouse (Fbp2, lgals4, Cd36, Ucp2, Pxmp4). Furthermore, several putative novel PPARα targets were identified that were commonly regulated in both species, including CREB3L3, KLF10, KLF11 and MAP3K8.Conclusions/SignificanceOur results suggest that PPARα activation has a major impact on gene regulation in human hepatocytes. Importantly, the role of PPARα as master regulator of hepatic lipid metabolism is generally well-conserved between mouse and human. Overall, however, PPARα regulates a mostly divergent set of genes in mouse and human hepatocytes.

Metallothionein plays a prominent role in the prevention of diabetic nephropathy by sulforaphane via up-regulation of Nrf2

366 Abrogation of S100B Expression in S100A1 Deficient Mice Improves Survival Post Myocardial Infarction

Introduction: We previously showed that an imbalance between polyubiquitinated proteins awaiting proteasomal degradation and proteasome activity is a main determinant of proteasome inhibitor (PI) sensitivity in MM. While PIs have radically improved survival of MM patients, resistance is inevitable over time and understanding the molecular mechanisms underlying it is critically important to develop novel therapies to improve patient outcomes. The proteasome stress response (PSR) is an evolutionarily conserved homeostatic mechanism triggered by insufficient proteasome activity and aimed at restoring homeostasis via de novo proteasome biogenesis. The PSR master regulator NRF1 is constitutively degraded by the proteasome in homeostatic conditions, but in face of proteasomal insufficiency is cleaved by the aspartic protease DDI2, translocates to the nucleus, and induces proteasome subunit gene transcription. It is unknown whether blocking DDI2 or NRF1 could target an intrinsic vulnerability of MM. Materials and methods: We used human MM cell lines with distinct baseline sensitivity to PIs. NRF1 cleavage and nuclear localization were assessed via western blotting. We used CRISPR-Cas9 to knock out (KO) DDI2 and NRF1. Cell viability or tumor growth of DDI2/NRF1 KO cells versus cells edited with a non-targeting gRNA were compared in in vitro and in vivo growth competition studies, respectively. Addback studies were performed by stably expressing WT or aspartic protease dead DDI2 in DDI2 KO AMO1-VR monoclones. Chymotryptic-like proteasome activity was measured via cleavage of a fluorescent substrate upon incubation with protein lysates from DDI2 WT, KO, or addback cells. Results: We detected full-length and cleaved NRF1 in human MM cell lines, but not other hematologic cancer cell lines, suggesting constitutively active PSR in MM. Query of the dependency map (depmap.org) shows that MM is the cell line type most highly dependent on DDI2. Consistently, DDI2 or NRF1 KO is cytotoxic alone or in combination with PI across a panel of MM cells with distinct PI sensitivity, including de novo, PI-resistant KMS20. In vivo, DDI2 KO leads to reduced plasmacytoma formation in NOD SCID mice and results in prolongation of animal survival. While biallelic DDI2 or NRF1 KO monoclones could not be generated across 7 distinct MM cell lines, consistent with these genes being essential, we successfully established DDI2 KO monoclones in AMO1-VR, an isogenic AMO1 cell line variant adapted to grow in continuous bortezomib. Even in this cell line model of acquired PI resistance, DDI2 KO sensitized cells to PI carfilzomib. In this model, DDI2 KO blocks NRF1 cleavage and nuclear import, thereby impairing proteasome recovery after irreversible PI treatment and sensitizing to PI. Wild-type, but not catalytically-dead DDI2 addback rescues these phenotypes, confirming a causative link. Conclusions: Our data show that MM cells are intrinsically dependent on an intact DDI2/NRF1 axis to survive in baseline conditions and upon proteasomal inhibition. We propose that DDI2 is an unexplored, promising molecular target for MM treatment by disrupting the PSR and exacerbating proteotoxicity. This study provides the preclinical rationale for the development of novel therapeutics targeting the DDI2/NRF1 pathway to overcome acquired and de novo PI resistance and improve patient outcomes in MM. Citation Format: Tianzeng Chen, Matthew Ho, Jenna Briere, Maria Moscvin, Peter G. Czarnecki, Kenneth C. Anderson, T. Keith Blackwell, Giada Bianchi. Multiple myeloma cells depend on the NRF1-DDI2 proteasome stress response pathway for survival [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr LB110.

To quantitatively assess the global burden and health risks associated with dietary and cigarette-related cadmium (Cd) exposure, and to provide a scientific basis for developing public health policies for the prevention and control of global Cd exposure. This study combined the Cd concentration data in foods and cigarettes and their consumption data to assess the Cd exposure levels from these two sources. The toxicity kinetics (TK) model was used to convert dietary Cd exposure into urinary Cd (U-Cd) exposure to further evaluate the burden of cardiovascular disease (CVD) caused by dietary Cd exposure. The risk assessment model of the United States Environmental Protection Agency (USEPA) was adopted to evaluate the cancer and non-cancer risks caused by cigarette-related Cd exposure. The global average daily dietary Cd intake was 2.20 μg/kg bw/day. The daily Cd exposure to cigarettes was 0.0359 μg/kg bw/day. The proportions of the burden of CVD, stroke and coronary heart disease (CHD) explained by dietary Cd intake were 6.08%, 3.34% and 2.74%, respectively. The excess lifetime cancer risk (ELCR) due to cigarette-related Cd exposure was 0.0037, and the non-cancer hazard quotient (NCHQ) was 26.89. Cd exposure in diet and cigarettes significantly affects the global CVD burden and cancer risk. This study emphasizes the importance of reducing Cd exposure in the environment and formulating relevant policies to mitigate health risks, including strengthening Cd control in food and implementing effective and reasonable tobacco control policies.