Zooming in and out of ferroptosis in human disease / 医学前沿

Ferroptosis is defined as an iron-dependent regulated form of cell death driven by lipid peroxidation. In the past decade, it has been implicated in the pathogenesis of various diseases that together involve almost every organ of the body, including various cancers, neurodegenerative diseases, cardiovascular diseases, lung diseases, liver diseases, kidney diseases, endocrine metabolic diseases, iron-overload-related diseases, orthopedic diseases and autoimmune diseases. Understanding the underlying molecular mechanisms of ferroptosis and its regulatory pathways could provide additional strategies for the management of these disease conditions. Indeed, there are an expanding number of studies suggesting that ferroptosis serves as a bona-fide target for the prevention and treatment of these diseases in relevant pre-clinical models. In this review, we summarize the progress in the research into ferroptosis and its regulatory mechanisms in human disease, while providing evidence in support of ferroptosis as a target for the treatment of these diseases. We also discuss our perspectives on the future directions in the targeting of ferroptosis in human disease.

Progress on epigenetic regulation of iron homeostasis / 浙江大学学报·医学版

Iron homeostasis plays an important role for the maintenance of human health. It is known that iron metabolism is tightly regulated by several key genes, including divalent metal transport-1(), transferrin receptor 1(), transferrin receptor 2(), ferroportin(), hepcidin(), hemojuvelin() and . Recently, it is reported that DNA methylation, histone acetylation, and microRNA (miRNA) epigenetically regulated iron homeostasis. Among these epigenetic regulators, DNA hypermethylation of the promoter region of , and bone morphogenetic protein 6 () genes result in inhibitory effect on the expression of these iron-related gene. In addition, histone deacetylase (HADC) suppresses gene expression. On the contrary, HADC inhibitor upregulates gene expression. Additional reports showed that miRNA can also modulate iron absorption, transport, storage and utilization via downregulation of and other genes. It is noteworthy that some key epigenetic regulatory enzymes, such as DNA demethylase TET2 and histone lysine demethylase JmjC KDMs, require iron for the enzymatic activities. In this review, we summarize the recent progress of DNA methylation, histone acetylation and miRNA in regulating iron metabolism and also discuss the future research directions.

The role of ferroptosis in chronic diseases / 浙江大学学报·医学版

Recently, ferroptosis, an iron-dependent novel type of cell death, has been characterized as an excessive accumulation of lipid peroxides and reactive oxygen species. Emerging studies demonstrate that ferroptosis not only plays an important role in the pathogenesis and progression of chronic diseases, but also functions differently in the different disease context. Notably, it is shown that activation of ferroptosis could potently inhibit tumor growth and increase sensitivity to chemotherapy and immunotherapy in various cancer settings. As a result, the development of more efficacious ferroptosis agonists remains the mainstay of ferroptosis-targeting strategy for cancer therapeutics. By contrast, in non-cancerous chronic diseases, including cardiovascular & cerebrovascular diseases and neurodegenerative diseases, ferroptosis functions as a risk factor to promote these diseases progression through triggering or accelerating tissue injury. As a matter of fact, blocking ferroptosis has been demonstrated to effectively prevent ischemia-reperfusion heart disease in preclinical animal models. Therefore, it is a promising field to develope potent ferroptosis inhibitors for preventing and treating cardiovascular & cerebrovascular diseases and neurodegenerative diseases. In this article, we summarize the most recent progress on ferroptosis in chronic diseases, and draw attention to the possible clinical impact of this recently emerged ferroptosis modalities.

The zinc transporter Slc39a5 controls glucose sensing and insulin secretion in pancreatic β-cells via Sirt1- and Pgc-1α-mediated regulation of Glut2

Zinc levels are high in pancreatic β-cells, and zinc is involved in the synthesis, processing and secretion of insulin in these cells. However, precisely how cellular zinc homeostasis is regulated in pancreatic β-cells is poorly understood. By screening the expression of 14 Slc39a metal importer family member genes, we found that the zinc transporter Slc39a5 is significantly down-regulated in pancreatic β-cells in diabetic db/db mice, obese ob/ob mice and high-fat diet-fed mice. Moreover, β-cell-specific Slc39a5 knockout mice have impaired insulin secretion. In addition, Slc39a5-deficient pancreatic islets have reduced glucose tolerance accompanied by reduced expression of Pgc-1α and its downstream target gene Glut2. The down-regulation of Glut2 in Slc39a5-deficient islets was rescued using agonists of Sirt1, Pgc-1α and Ppar-γ. At the mechanistic level, we found that Slc39a5-mediated zinc influx induces Glut2 expression via Sirt1-mediated Pgc-1α activation. These findings suggest that Slc39a5 may serve as a possible therapeutic target for diabetes-related conditions.

Influence of zinc on expression of zinc transporter mRNA in Caco2 cells / 中国组织工程研究

BACKGROUND: Decreasing of absorption of zinc from small intestine can induce dermatitis, alopecia, growth and developmental disorder and so on. It is not very clear that how to keep homeostasis when there is low zinc concentration. The discoveries of zinc transporters and relative researches provide new study direction.OBJECTIVE: To study the effect of different zinc concentration on the expressions of divalent metal transporter 1 (DMT1) and human zinc-regulated transporter (ZRT), iron-regulated transporter (IRT)-like protein (ZIP) 4mRNA, and analyze the potential pathway of absorption of zinc from small intestine in low zinc concentration.DESIGN: Blank-controlled experiment.SETTING: Department of Military Hygiene, Navy Faculty, Second Military Medical University of Chinese PLA.MATERIALS: The experiment was accomplished in Department of Military Hygiene, Navy Faculty of Second Military Medical University of Chinese PLA between October 2004 and May 2005. Materials were human colon adenocarcinoma cells Caco2 that were purchased from Shanghai Institute of Cell of Chinese Academy of Sciences.Time-dependent effect: The expression of DMT1 and ZIP4 mRNA was detected with reverse transcription-polymerase chain reaction (RT-PCR) at 0,dependent effect: The expression of DMT1 and ZIP4 mRNA were measured after the 0, 2.5, 5, 7.5 and 10 μmol/L TPEN exposure, respectively, by RT-PCR.MAIN OUTCOME MEASURES: Time-and dose-dependent effect of zinc on the expression of DMT1 and ZIP4 mRNA in Caco2 cells.RESULTS: ①Time-dependent effect: Compared with 0 hour, the expression of DMT1 mRNA obviously increased at 6, 8 and 10 hours (P ＜ 0.05 ), but there was no significant change at 2 and 4 hours. The expression of ZIP4 mRNA markedly increased in all timing, and ZIP4 mRNA level at the 6th hour reached the peak with the prolongation of low zinc duration,which was 2.1 times ofthat at 0 hour. ②Dose-dependent effect: The expression of DMT1 mRNA distinctly increased at the concentration of 7.5 and 10 μmol/L TPEN exposure as compared with that of the control group (P ＜ 0.05), but there was no significant change at 2.5 and 5 μmol/L. The ZIP4 mRNA expression increased with the increasing of the concentration of TPEN, the expression of ZIP4 mRNA was 2.7 times of that at 0 μmol/L. CONCLUSION: Zinc can regulate the expression of DMT1 and ZIP4 mRNA in Caco2 cells, and there is time-and dose-dependent effect. But the mRNA expression of ZIP4 is more sensitive and prompt than DMT1. Cells can upregulate the expression of DMT1 and ZIP4 mRNA to keep the homeostasis in low zinc condition.

Effects of different zinc intakes on brain and testis expression of zinc transporter 3 mRNA in weaned mice / 第二军医大学学报

Objective:To observe the growth and development of the weaned mice fed with different levels of dietary zinc and to explore the expression of zinc transporter 3(ZnT3) mRNA induced by different dietary zinc intakes. Methods: Twenty male weaned mice (postnatal day 21) were divided into 4 groups: zinc deficient (ZD), zinc adequate(ZA), zinc supplemental (ZS) and pair fed(PF). Mice were fed with different levels of dietary zinc for 3 weeks (from postnatal day 21 to postnatal day 42) ;the zinc contents of ZD, ZA, ZS and PF group were 1 mg/kg, 30 mg/kg, 180 mg/kg and 180 mg/kg respectively. From postnatal day 21 to postnatal day 42, the diet intakes and weight of the mice were measured everyday. On postnatal day 42, the mice were sacrificed and tissues were immediately isolated and frozen lor RNA extraction. The serum zinc concentrations were measured by AAS and the expression of ZnT3 mRNA was determined by semiquantitative RT-PCR. Results: The dietary intakes and weight of ZD mice were much lower than that of other groups(P3

Study of zinc element and ZnT3 mRNA expression in mouse brain / 中国病理生理杂志

AIM:To explore the interaction and function between ZnT3 mRNA expression and zinc elemental distribution in brain slice of mouse.METHODS:Zinc distribution was determined by SRXRF and ZnT3 mRNA expression in tissue was examined by RT-PCR method.RESULTS:Zinc content in cerebral cortex and hippocampus was significantly higher than that in other positions.The highest expression of ZnT3 mRNA was observed in cerebrum,hippocampus and testis.However,the ZnT3 mRNA was not detected in heart,liver,lung,spleen,kidney,intestine,olfactory bulb and cerebellum.CONCLUSION:ZnT3 facilitates the accumulation of zinc in synaptic vesicles and may play important roles in structuring of vesicular zinc pool.

Effect of zinc on expression of zinc transporter 1 and metallothionein mRNA in primary cultured hippocampal neurons / 第二军医大学学报

Objective:To study the concentration response and time course of zinc transporter 1 (ZnT 1) and metallothionein (MT1/MT2) mRNA,as well as the cell viability to zinc exposure in primary cultured new born rats hippocampal neuron s. Methods: The cell viability were determined by trypan blue s taining at various concentrations of Zn 2+ (0, 50, 100, 125, 150, 175, 200 ?mol/L). The expression of ZnT 1, MT1 and MT2 mRNA to various concentrations of zinc exposure(0, 50, 75, 100, 125, 150 ?mol/L) and to 100 ?mol/L zinc exposure for different times (0, 2, 4, 6, 8 h) were determined b y real time fluorescent quantitative PCR. Results: The viabilit y of the neurons decreased significantly after 48 h once the concentration of Zn 2+ exceeded 125 ?mol/L,and the expression of ZnT 1 mRNA was in proportion to the increment of zinc.The expression of MT1/MT2 mRNA reached a plateau when the zinc concentration exceeding 75 ?mol/L. The expression of ZnT 1 mRNA peaked on about 2 h.However, the expression of MT1/MT2 mRNA reached its maximal around 6 h at the concentration of 100 ?mol/L. Conclusion: These results imply that although both MTs and ZnT 1 can attenuate the zinc toxicity, they may play different roles at different phases. ZnT 1 enhance the efflux of zinc prior to the sequesteration by MTs. Th e action of ZnT 1 may be durable, but the role of MTs may be satiable.