Ferroptosis Altered microRNAs Expression in HT-1080 Fibrosarcoma Cells Based on Small RNA Sequencing and Bioinformatics Analysis.

Iron is an essential trace element in the human body. However, excess iron is harmful and may cause ferroptosis. The expression and role of microRNAs (miRNAs) in ferroptosis remain largely unknown. A model of ferroptosis induced by ferric ammonium citrate in HT-1080 cells was established in this study. The miRNAs expression profiles of the control and iron groups were obtained using small RNA sequencing and verified using qRT-PCR. A total of 1346 known miRNAs and 80 novel miRNAs were identified, including 12 up-regulated differentially expressed miRNAs (DE-miRNAs) and 16 down-regulated DE-miRNAs. SP1 was the most important upstream transcription factor regulating DE-miRNAs. The downstream target genes of DE-miRNAs were predicted based on miRDB, TargetScan, and miRBase databases, and 403 common target genes were screened. GO annotation and KEGG analysis revealed that the target genes were mainly involved in various biological processes and regulatory pathways, especially the MAPK signaling pathway and PI3K-Akt signaling pathway. Afterwards, a target genes network was constructed using STRING and Cytoscape, and the hub genes were compared with the ferroptosis database (FerrDb V2) to discover the hub genes related to ferroptosis. EGFR, GSK3B, PARP1, VCP, and SNCA were screened out. Furthermore, a DE-miRNAs-target genes network was constructed to explore key DE-miRNAs. hsa-miR-200c-3p, hsa-miR-26b-5p, and hsa-miR-7-5p were filtered out. Comprehensive bioinformatics analysis of miRNAs and its upstream and downstream regulation in ferroptosis in HT-1080 cells using small RNA sequencing is helpful for understanding the role of miRNAs in iron overload-related diseases and ferroptosis-targeted therapy for cancer.

Plasma non-transferrin-bound iron uptake by the small intestine leads to intestinal injury and intestinal flora dysbiosis in an iron overload mouse model and Caco-2 cells.

Iron overload often occurs during blood transfusion and iron supplementation, resulting in the presence of non-transferrin-bound iron (NTBI) in host plasma and damage to multiple organs, but effects on the intestine have rarely been reported. In this study, an iron overload mouse model with plasma NTBI was established by intraperitoneal injection of iron dextran. We found that plasma NTBI damaged intestinal morphology, caused intestinal oxidative stress injury and reactive oxygen species (ROS) accumulation, and induced intestinal epithelial cell apoptosis. In addition, plasma NTBI increased the relative abundance of Ileibacterium and Desulfovibrio in the cecum, while the relative abundance of Faecalibaculum and Romboutsia was reduced. Ileibacterium may be a potential microbial biomarker of plasma NTBI. Based on the function prediction analysis, plasma NTBI led to the weakening of intestinal microbiota function, significantly reducing the function of the extracellular structure. Further investigation into the mechanism of injury showed that iron absorption in the small intestine significantly increased in the iron group. Caco-2 cell monolayers were used as a model of the intestinal epithelium to study the mechanism of iron transport. By adding ferric ammonium citrate (FAC, plasma NTBI in physiological form) to the basolateral side, the apparent permeability coefficient (Papp) values from the basolateral to the apical side were greater than 3×10-6 cm s-1. Intracellular ferritin level and apical iron concentration significantly increased, and SLC39A8 (ZIP8) and SLC39A14 (ZIP14) were highly expressed in the FAC group. Short hairpin RNA (shRNA) was used to knock down ZIP8 and ZIP14 in Caco-2 cells. Transfection with ZIP14-specific shRNA decreased intracellular ferritin level and inhibited iron uptake. These results revealed that plasma NTBI may cause intestinal injury and intestinal flora dysbiosis due to the uptake of plasma NTBI from the basolateral side into the small intestine, which is probably mediated by ZIP14.

Growth of Mesoscale Ordered Two-Dimensional Hydrogen-Bond Organic Framework with the Observation of Flat Band.

Flat bands (FBs), presenting a strongly interacting quantum system, have drawn increasing interest recently. However, experimental growth and synthesis of FB materials have been challenging and have remained elusive for the ideal form of monolayer materials where the FB arises from destructive quantum interference as predicted in 2D lattice models. Here, we report surface growth of a self-assembled monolayer of 2D hydrogen-bond (H-bond) organic frameworks (HOFs) of 1,3,5-tris(4-hydroxyphenyl)benzene (THPB) on Au(111) substrate and the observation of FB. High-resolution scanning tunneling microscopy or spectroscopy shows mesoscale, highly ordered, and uniform THPB HOF domains, while angle-resolved photoemission spectroscopy highlights a FB over the whole Brillouin zone. Density-functional-theory calculations and analyses reveal that the observed topological FB arises from a hidden electronic breathing-kagome lattice without atomically breathing bonds. Our findings demonstrate that self-assembly of HOFs provides a viable approach for synthesis of 2D organic topological materials, paving the way to explore many-body quantum states of topological FBs.

Kinetic Controlled Chirality Transfer and Induction in 2D Hydrogen-Bonding Assemblies of Glycylglycine on Au(111).

Chirality transfer is of vital importance that dominates the structure and functionality of biological systems and living matters. External physical stimulations, e.g. polarized light and mechanical forces, can trigger the chirality symmetry breaking, leading to the appearance of the enantiomeric entities created from a chiral self-assembly of achiral molecule. Here, several 2D assemblies with different chirality, synthesized on Au(111) surface by using achiral building blocks - glycylglycine (digly), the simplest polypeptide are reported. By delicately tuning the kinetic factors, i.e., one-step slow/rapid deposition, or stepwise slow deposition with mild annealing, achiral square hydrogen-bond organic frameworks (HOF), homochiral rhombic HOF and racemic rectangular assembly are achieved, respectively. Chirality induction and related symmetry broken in assemblies are introduced by the handedness (H-bond configurations in principle) of the assembled motifs and then amplified to the entire assemblies via the interaction between motifs. The results show that the chirality transfer and induction of biological assemblies can be tuned by altering the kinetic factors instead of applying external forces, which may offer an in-depth understanding and practical approach to peptide chiral assembly on the surfaces and can further facilitate the design of desired complex biomolecular superstructures.

Plasma Non-transferrin-Bound Iron Could Enter into Mice Duodenum and Negatively Affect Duodenal Defense Response to Virus and Immune Responses.

Plasma non-transferrin-bound iron (NTBI) exists when the plasma iron content exceeds the carrying capacity of transferrin and can be quickly cleared by the liver, pancreas, and other organs. However, whether it could enter the small intestine and its effects still remain unclear. Herein, these issues were explored. Mice were intravenously administrated of ferric citrate (treatment) or citrate acid (control) 10 min after the saturation of the transferrin. Two hours later, hepatic, duodenal, and jejunal iron content and distribution were measured and duodenal transcriptome sequencing was performed. Significant increase of duodenal and hepatic iron content was detected, indicating that plasma NTBI could be absorbed by the duodenum as well as the liver. A total of 103 differentially expressed genes were identified in the duodenum of mice in the treatment group compared to the control group. Gene Ontology (GO) functional analysis of these genes showed that they were mainly involved in defense response to virus and immune response. The results of Kyoto Encyclopedia of Genes and Genomes pathway (KEGG) analysis revealed that there were major changes in the hematopoietic cell lineage and some virus infection pathways between the two groups. Determination of 7 cytokines in the duodenum were further conducted, which demonstrated that the anti-inflammatory factors interferon (IL)-4 and IL-10 in the duodenum were significantly decreased after NTBI uptake. Our findings revealed that NTBI in plasma can enter the duodenum, which would change the duodenal hematopoietic cell lineage and have a negative impact on defense response to the virus and immune responses.

Complex supramolecular tessellations with on-surface self-synthesized C60 tiles through van der Waals interaction.

Supramolecular tessellation with self-synthesized (C60)7 tiles is achieved based on a cooperative interaction between co-adsorbed C60 and octanethiol (OT) molecules. Tile synthesis and tiling take place simultaneously on a gold substrate leading to a two-dimensional lattice of (C60)7 tiles with OT as the binder molecule filling the gaps between the tiles. This supramolecular tessellation is featured with simultaneous on-site synthesis of tiles and self-organized tiling. In the absence of specific functional groups, the key to ordered tiling for the C60/OT system is the collective van der Waals (vdW) interaction among a large number of molecules. This bicomponent system herein offers a way for the artificial synthesis of 2D complex vdW supramolecular tessellations.

Effect of Long-Term and Short-Term Imbalanced Zn Manipulation on Gut Microbiota and Screening for Microbial Markers Sensitive to Zinc Status.

Zinc (Zn) imbalance is a common single-nutrient disorder worldwide, but little is known about the short-term and long-term effects of imbalanced dietary zinc in the intestinal microbiome. Here, 3-week-old C57BL/6 mice were fed diets supplemented with Zn at the doses of 0 (low Zn), 30 (control Zn), 150 (high Zn), and 600 mg/kg of body weight (excess Zn) for 4 weeks (short term) and 8 weeks (long term). The gut bacterial composition at the phyla, genus, and species levels were changed as the result of the imbalanced Zn diet (e.g., Lactobacillus reuteri and Akkermansia muciniphila). Moreover, pathways including carbohydrate, glycan, and nucleotide metabolism were decreased by a short-term low-Zn diet. Valeriate production was suppressed by a long-term low-Zn diet. Pathways such as drug resistance and infectious diseases were upregulated in high- and excess-Zn diets over 4-week and 8-week intervals. Long-term zinc fortification doses, especially at the high-Zn level, suppressed the abundance of short-chain fatty acids (SCFAs)-producing genera as well as the concentrations of metabolites. Finally, Melainabacteria (phylum) and Desulfovibrio sp. strain ABHU2SB (species) were identified to be potential markers for Zn status with high accuracy (area under the curve [AUC], >0.8). Collectively, this study identified significant changes in gut microbial composition and its metabolite concentration in altered Zn-fed mice and the relevant microbial markers for Zn status. IMPORTANCE Zn insufficiency is an essential health problem in developing countries. To prevent the occurrence of zinc deficit, zinc fortification and supplementation are widely used. However, in developed countries, the amounts of Zn consumed often exceed the tolerable upper intake limit. Our results demonstrated that dietary Zn is an essential mediator of microbial community structure and that both Zn deficiency and Zn overdose can generate a dysbiosis in the gut microbiota. Moreover, specific microbial biomarkers of Zn status were identified and correlated with serum Zn level. Our study found that a short-term low-Zn diet (0 mg/kg) and a long-term high-zinc diet (150 mg/kg) had obvious negative effects in a mouse model. Thus, these results indicate that the provision and duration of supplemental Zn should be approached with caution.

Lipidomics reveals perturbations in the liver lipid profile of iron-overloaded mice.

Iron overload is an important contributor to disease. The liver, the major site of iron storage in the body, is a key organ impacted by iron overload. While several studies have reported perturbations in liver lipids in iron overload, it is not clear, on a global scale, how individual liver lipid ions are altered. Here, we used lipidomics to study the changes in hepatic lipid ions in iron-overloaded mice. Iron overload was induced by daily intraperitoneal injections of 100 mg/kg body weight iron dextran for 1 week. Iron overload was verified by serum markers of iron status, liver iron quantitation, and Perls stain. Compared with the control group, the serum of iron-overload mice exhibited low levels of urea nitrogen and high-density lipoprotein (HDL), and high concentrations of total bile acid, low-density lipoprotein (LDL), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH), suggestive of liver injury. Moreover, iron overload disrupted liver morphology, induced reactive oxygen species (ROS) production, reduced superoxide dismutase (SOD) activity, caused lipid peroxidation, and led to DNA fragmentation. Iron overload altered the overall composition of lipid ions in the liver, with significant changes in over 100 unique lipid ions. Notably, iron overload selectively increased the overall abundance of glycerolipids and changed the composition of glycerophospholipids and sphingolipids. This study, one of the first to report iron-overload induced lipid alterations on a global lipidomics scale, provides early insight into lipid ions that may be involved in iron overload-induced pathology.

Network pharmacology-based identification of the key mechanism of quercetin acting on hemochromatosis.

Hemochromatosis is an iron overload disease, which lacks nutritional intervention strategies. This study explored the protective effect of quercetin on hemochromatosis and its possible mechanism through network pharmacology. We used Online Mendelian Inheritance in Man to screen the disease targets of hemochromatosis, and further constructed a potential protein interaction network through STITCH. The above-mentioned targets revealed by Gene enrichment analysis have played a significant role in ferroptosis, mineral absorption, basal cell carcinoma, and related signal pathways. Besides, the drug likeness of quercetin obtained by Comparative Toxicogenomics Database was evaluated by Traditional Chinese Medicine Systems Pharmacology, and potential drug targets identified by PharmMapper and similar compounds identified by PubChem were selected for further research. Moreover, gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed the relationship between quercetin and glycosylation. Furthermore, we performed experiments to verify that the protective effect of quercetin on iron overload cells is to inhibit the production of reactive oxygen species, limit intracellular iron, and degrade glycosaminoglycans. Finally, iron-induced intracellular iron overload caused ferroptosis, and quercetin and fisetin were potential ferroptosis inhibitors. In conclusion, our study revealed the correlation between hemochromatosis and ferroptosis, provided the relationship between the target of quercetin and glycosylation, and verified that quercetin and its similar compounds interfere with iron overload related disease. Our research may provide novel insights for quercetin and its structurally similar compounds as a potential nutritional supplement for iron overload related diseases.

Selection of copper and zinc dosages in pig diets based on the mutual benefit of animal growth and environmental protection.

Dietary copper and zinc additives facilitate the growth and development of animals, but heavy metal in feces threatens the ecological environment, and balance is the key to solving the problem. In this study, a trial of 2000 pigs (early nursery, 9-15 kg; late nursery, 15-25 kg; grower: 25-60 kg) was conducted to analyze the effects of different diets (gradient dosage of copper and zinc additives) on growth performance, antioxidant performance, immune function, and fecal heavy metal excretion of piglets and growing pigs. Although no significant differences were observed in average daily gain (ADG) and average daily feed intake (ADFI) between treatments during the entire nursery-grower period, the addition of appropriate high doses of copper and zinc to the diet had a beneficial effect on the antioxidant status and immune function of weaned piglets. Especially at early nursery, compared with the low-copper group (5 mg/kg Cu), the high-copper group (120 mg/kg Cu) could significantly increase the peroxidase (POD), glutathione peroxidase (GSH-PX), total antioxidant capacity (T-AOC), catalase (CAT) and copper/zinc superoxide dismutase (Cu/Zn-SOD), cortisol in the serum. Moreover, the addition of zinc and copper in the diet not only increased the concentration of corresponding trace elements in the serum, but also affected the concentration of other trace elements in the serum. The reduction of copper and zinc content in the diet contributed to reducing the copper and zinc content in feces. In conclusion, we have formulated the mutual benefit dosages of copper and zinc (9-15 kg: 5 mg/kg Cu and 50 mg/kg Zn; 15-25 kg: 4 mg/kg Cu and 50 mg/kg Zn; 25-60 kg: 4 mg/kg Cu and 10 mg/kg Zn) for weaning piglets and growing pigs, which would help ensure the healthy growth of animals and reduce environmental heavy metal residues. CAPSULE: This study developed a mutually beneficial dose of copper and zinc in pig diets, which promotes animal growth and protects the environment.

Tolerable upper intake level of iron damages the liver of weaned piglets.

Iron is one of the essential trace elements, which is often supplemented as an additive to meet the growing needs of toddlers and young animals. Recommended nutrient intake (RNI) and tolerable upper intake levels (UL) are always set when the iron is supplemented. The purpose of this study was to evaluate the subacute (28 days) toxicity of UL iron to weaned piglet liver. Thirty 23-day-old weaned piglets were divided into three groups and, respectively, supplemented with 100, 300 or 3000 (UL) mg/kg iron. UL iron caused significant weight loss in 4th week (p < 0.05). Divalent metal transporter 1(DMT1) decreased significantly, ferroportin 1 and ferritin increased significantly in the liver of UL iron group (p < 0.05). Although there was no significant effect on liver morphology, UL iron significantly increased hepatic iron, reactive oxygen species (ROS), malondialdehyde (MDA) and protein carbonyl (p < 0.05). UL iron significantly reduced glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalase (CAT) and total anti-oxidation capacity (T-AOC) in the liver (p < 0.05). Nuclear factor erythroid 2-related factor 2 (Nrf2) activated subunits of glutamate cysteine ligase (Gclc) and glutathione S-transferase A1 (Gsta1) upregulation in the UL iron group liver, thereby increasing resistance to oxidative stress. In conclusion, UL iron supplementation altered iron metabolism, generated free radicals, reduced antioxidant enzyme activity and activated Nrf2 signalling pathway in the weaned piglet liver.

In Situ Observation of Stepwise C-H Bond Scission: Deciphering the Catalytic Selectivity of Ethylbenzene-to-Styrene Conversion on TiO2.

The conversion of light alkanes to olefins is crucial to the chemical industry. The quest for improved catalytic performance for this conversion is motivated by current drawbacks including: expensive noble metal catalysts, poor conversion, low selectivity, and fast decay of efficiency. The in situ visualization of complex catalysis at the atomic level is therefore a major advance in the rational framework upon building the future catalysts. Herein, the catalytic C-H bond activations of ethylbenzene on TiO2(110)-(1 × 1) were explored with high-resolution scanning tunneling microscopy and first-principles calculations. We report that the first C-H bond scission is a two-step process that can be triggered by either heat or ultraviolet light at 80 K, with near 100% selectivity of ß-CH bond cleavage. This work provides fundamental understanding of C-H bonds cleavage of ethylbenzene on metal oxides, and it may promote the design of new catalysts for selective styrene production under mild conditions.

Iron homeostasis disorder in piglet intestine.

Iron plays an essential role in preventing iron deficiency anemia and ensuring the healthy growth of animals. The special physiological condition of piglets is the main cause of iron deficiency. Iron metabolism in the intestine is the basis for understanding the effects of iron on the health of piglets. In order to scientifically evaluate dietary iron supplementation doses, it is necessary to recognize the effects of iron deficiency and iron overload on piglet intestinal health. Besides, iron as a cofactor is essential for the growth of microorganisms, and microorganisms compete with the host to absorb iron. Under the stress of iron deficiency and iron overload, various control schemes (such as precise nutrition, element balance, elimination of oxidation, etc.) are effective measures to eliminate adverse effects. In this review, we comprehensively review recent findings on the effects of iron deficiency and iron overload on intestinal health. This review will provide a rational design strategy to achieve a reasonable iron supplement, which will guide the use of iron in animal husbandry.

Tolerable upper intake level of iron damages the intestine and alters the intestinal flora in weaned piglets.

Iron supplementation has been an intervention to improve iron storage and prevent iron deficiency anemia in weaned piglets and the recommended nutrient intake (RNI) and tolerable upper intake levels (UL) of iron have been established. The purpose of this study is to investigate the potential harm of UL iron to the gut and microbes of weaned piglets. Thirty 23 day old weaned piglets were assigned to three dietary treatments: a basal diet supplemented with 100 (RNI), 300, and 3000 (UL) mg FeSO4 per kg diet for 28 days. Then, we used the intestinal porcine epithelial cell line (IPEC-1) as a cell model to study the effect of UL iron on the gut of weaned piglets. Weaned piglets showed a significant decrease in villus height after feeding on a UL iron diet (P < 0.05). The protein levels of DMT1 and Zip14 decreased, and the protein levels of ferritin increased in the duodenal mucosa (P < 0.05) of UL iron fed weaned piglets. Moreover, UL iron also increased the content of ROS and malondialdehyde and decreased the activity of superoxide dismutase in the duodenal mucosa of weaned piglets (P < 0.05). The addition of UL iron to the diet significantly reduced the expression of tight junction proteins Claudin-1, Occludin, and ZO-1 in the duodenal mucosa of weaned piglets (P < 0.05). In the IPEC-1 cell model, iron induced the production of cytosolic and mitochondrial ROS and reduced the mitochondrial membrane potential, which in turn led to cellular vacuolation and fibrosis. Furthermore, UL iron significantly altered the cecum flora of weaned piglets, and the relative abundance of Clostridiales, Faecalibacterium, and Prevotellaceae decreased significantly (P < 0.05), while the relative abundance of Desulfovibrio and Anaerovibrio increased significantly (P < 0.05). In conclusion, UL iron caused damage to the intestinal villi, induced oxidative stress, reduced iron absorption protein, damaged the intestinal barrier, and modified the intestinal microbial structure in weaned piglets.

Effects of Eucommia ulmoides leaf extracts on growth performance, antioxidant capacity and intestinal function in weaned piglets.

Eucommia ulmoides is traditional Chinese medicine, and it possesses several potential bioactivities, such as anti-inflammatory, antioxidant and immune regulatory activities. This study was conducted to determine the effects of dietary Eucommia ulmoides leaf extracts (ELE) on growth performance, antioxidant capacity and intestinal function of weaned piglets. Two hundred crossbred (Duroc × Landrace × Yorkshire) piglets with an average initial weight of 12.96 ± 0.28 kg were randomly allotted to five treatments: C0 (basal diet), C1 (basal diet + antibiotics) and basal diet supplemented with increasing levels of ELE (0.2, 0.3 or 0.4 g/kg of feed). The results showed that ELE or antibiotics supplementation remarkably decreased diarrhoea rate and 0.3 g/kg ELE increased average daily gain compared with C0 (p < .05). 0.3 g/kg ELE increased alkaline phosphatase (AKP) levels and total antioxidant capacity (T-AOC) in serum and liver, as well as increased the content of serum albumin and total protein (TP) compared with the C0 (p < .05). The lipase activity of duodenum content and trypsin activity of jejunum content were improved fed diets containing 0.3 g/kg ELE compared with C0 (p < .05). The 0.3 g/kg ELE treatments have a higher villus height of the duodenum and jejunum compared with the C0 (p < .05). These results suggested that ELE supplementation had beneficial effects on antioxidant and intestinal function in weaned piglets, which also could increase growth performance and decreased diarrhoea rate. Accordingly, ELE is a potential alternative to antibiotics.

Comparing the Influence of High Doses of Different Zinc Salts on Oxidative Stress and Energy Depletion in IPEC-J2 Cells.

The current study aimed to investigate the influence of four supplemental zinc salts (chelated: Zn glycine; non-chelated: Zn sulfate, Zn citrate, Zn gluconate) among different zinc concentrations (30-300 µM) on cell proliferation, oxidative stress, and energy depletion in intestinal porcine jejunum epithelial cells (IPEC-J2). Different zinc salts affected cell viability in a time- and dose-dependent manner, which was mainly dependent on the uptake of intracellular Zn2+. Intracellular Zn2+ of Zn sulfate has taken up almost twice as high as Zn glycine when cells were loaded with 100-200 µM zinc. After loading cells with 300 µM zinc, Zn glycine and Zn sulfate had a similar trend in accumulation of Zn2+. When the intracellular Zn2+ overloads, cells will gradually be damaged and subsequently die bearing biochemical features of necrosis or late apoptosis. Meanwhile, obviously, increased levels of intracellular ROS, mitochondrial ROS, MDA, and NO and decreased levels of GSH were observed. Excessive intracellular Zn2+ significantly decreased mitochondria membrane potential accompanied by an obvious loss of ATP and NAD+ levels. Overall, exposure to high doses of zinc salts caused cell damage, which was mainly dependent on the uptake of Zn2+. Zinc overload induced oxidative stress and energy depletion in IPEC-J2 cells, and the cell damage with non-chelated zinc addition was more serious than Zn glycine.

Iron Transport from Ferrous Bisglycinate and Ferrous Sulfate in DMT1-Knockout Human Intestinal Caco-2 Cells.

This experiment was conducted to investigate the transport characteristics of iron from ferrous bisglycinate (Fe-Gly) in intestinal cells. The divalent metal transporter 1 (DMT1)-knockout Caco-2 cell line was developed by Crispr-Cas9, and then the cells were treated with ferrous sulfate (FeSO4) or Fe-Gly to observe the labile iron pool and determine their iron transport. The results showed that the intracellular labile iron increased significantly with Fe-Gly or FeSO4 treatment, and this phenomenon was evident over a wide range of time and iron concentrations in the wild-type cells, whereas in the knockout cells it increased only after processing with high concentrations of iron for a long time (p < 0.05). DMT1-knockout suppressed the synthesis of ferritin and inhibited the response of iron regulatory protein 1 (IRP-1) and IRP-2 to these two iron sources. The expression of peptide transporter 1 (PepT1) was not altered by knockout or iron treatment. Interestingly, the expression of zinc-regulated transporter (ZRT) and iron-regulated transporter (IRT)-like protein 14 (Zip14) was elevated significantly by knockout and iron treatment in wild-type cells (p < 0.05). These results indicated that iron from Fe-Gly was probably mainly transported into enterocytes via DMT1 like FeSO4; Zip14 may play a certain role in the intestinal iron transport.

Effects of intracellular iron overload on cell death and identification of potent cell death inhibitors.

Iron overload causes many diseases, while the underlying etiologies of these diseases are unclear. Cell death processes including apoptosis, necroptosis, cyclophilin D-(CypD)-dependent necrosis and a recently described additional form of regulated cell death called ferroptosis, are dependent on iron or iron-dependent reactive oxygen species (ROS). However, whether the accumulation of intracellular iron itself induces ferroptosis or other forms of cell death is largely elusive. In present study, we study the role of intracellular iron overload itself-induced cell death mechanisms by using ferric ammonium citrate (FAC) and a membrane-permeable Ferric 8-hydroxyquinoline complex (Fe-8HQ) respectively. We show that FAC-induced intracellular iron overload causes ferroptosis. We also identify 3-phosphoinositide-dependent kinase 1 (PDK1) inhibitor GSK2334470 as a potent ferroptosis inhibitor. Whereas, Fe-8HQ-induced intracellular iron overload causes unregulated necrosis, but partially activates PARP-1 dependent parthanatos. Interestingly, we identify many phenolic compounds as potent inhibitors of Fe-8HQ-induced cell death. In conclusion, intracellular iron overload-induced cell death form might be dependent on the intracellular iron accumulation rate, newly identified cell death inhibitors in our study that target ferroptosis and unregulated oxidative cell death represent potential therapeutic strategies against iron overload related diseases.

Probing Phase Evolutions of Au-Methyl-Propyl-Thiolate Self-Assembled Monolayers on Au(111) at the Molecular Level.

A self-assembled monolayer (SAM) consisting of a mixture of CH3S-Au-SCH3, CH3S-Au-S(CH2)2CH3, and CH3(CH2)2S-Au-S(CH2)2CH3 was studied systematically using scanning tunneling microscopy and density functional calculations. We find that the SAM is subjected to frequent changes at the molecular level on the time scale of ∼minutes. The presence of CH3S or CH3S-Au as a dissociation product of CH3S-Au-SCH3 plays a key role in the dynamical behavior of the mixed SAM. Slow phase separation takes place at room temperature over hours to days, leading to the formation of methyl-thiolate-rich and propyl-thiolate-rich phases. Our results provide new insights into the chemistry of the thiolate-Au interface, especially for ligand exchange reaction in the RS-Au-SR staple motif.