Iron Loading Research Articles

Ablation of Na+/H+ exchanger‐3 prevents tissue iron loading in the Hfe mouse model of hereditary hemochromatosis

Several common hereditary disorders are associated with toxic iron overload which leads to liver cirrhosis, cardiomyopathy, and endocrine disorders. Hereditary hemochromatosis arises from mutations in the genes coding for any of several proteins involved in iron sensing (e.g. Hfe), hepcidin production (e.g. hemojuvelin), or hepcidin action, resulting in elevated iron absorption relative to the iron need. Divalent metal‐ion transporter‐1 (DMT1) is a H+‐coupled Fe2+ transporter and the principal or only mechanism by which nonheme iron is taken up at the intestinal brush border [Shawki A et al (2015) Am J Physiol Gastrointest Liver Physiol 309, G635–G647]. DMT1 is a validated therapeutic target in treating iron overload. We have shown that Na+/H+ exchanger‐3 (NHE3) is required for adequate iron absorption, via its physiological role in generating at the intestinal brush border an acidic microclimate that energizes DMT1‐mediated H+‐coupled Fe2+ transport [Shawki A et al (2016) Am J Physiol Gastrointest Liver Physiol 311, G423–G430], so we have explored here the contribution of NHE3 to pathological iron loading. We tested the hypothesis that NHE3 activity is necessary for pathological iron loading. We examined the effect of ablating the SLC9A3 gene coding for NHE3 in the Hfe mouse model of hereditary hemochromatosis. We measured tissue iron levels, hematological and blood‐iron variables, and the hepatic expression of Hamp1 (coding for hepcidin) by using qPCR in male and female FVB/N mice, age ≍ 120 d, fed a normal diet (NIH‐07). We examined four genotypes in both sexes: wildtype mice, NHE3 knockout (NHE3−/−), Hfe knockout (hemochromatosis disease model, Hfe−/−), and double knockout (NHE3−/− | Hfe−/−) (n = 12–26 mice per group). We chose α = 0.05, and analyzed our data (mean, SD) by using multifactorial ANOVA. We found that ablation of NHE3 prevented the liver iron loading characteristic of the Hfe−/− mouse model, an effect that was independent of sex. We observed a similar effect on iron loading in the spleen. Ablation of NHE3 produced no sign of overt anemia. Hepatic expression of hepcidin was depressed in NHE3−/− and in Hfe−/− mice relative to wildtype mice, and remained low in the NHE3−/− | Hfe−/− mice, providing a plausible explanation for the observation that, despite correction of the tissue iron levels in NHE3−/− | Hfe−/− mice, iron levels remained high in the readily accessible serum iron pool (typically 0.1% of total body iron). We conclude that ablation of NHE3 prevents pathological tissue iron loading in the Hfe mouse model of hemochromatosis. Pharmacological blockade of NHE3 may offer a means of inhibiting iron absorption in hereditary hemochromatosis.

Intestinal Dmt1 is Required for Iron Loading in Mice Modeling β‐Thalassemia Intermedia

β‐thalassemia intermedia (βTI) is characterized by chronic anemia, ineffective erythropoiesis, and excessive intestinal iron absorption leading to systemic iron overload. Divalent metal‐ion transporter 1 (DMT1), the main intestinal iron transporter, may mediate excessive iron absorption in Th3/+ mice, which model βTI.ObjectiveTo determine if intestinal DMT1 is required for iron‐loading in beta‐thalassemia, and if so, to utilize a ginger nanoparticle‐derived lipid vector (GDLVs) siRNA delivery system to normalize iron absorption in Th3/+ mice.HypothesisDMT1 mediates excessive iron absorption in βTI mice and decreasing DMT1 expression by GDLVs‐siRNA will prevent iron accumulation in these mice.MethodsTh3/+ mice were crossed with mice lacking intestinal DMT1 generating double KOs. Also, weanling mice were gavaged daily for 16 days with GDLVs carrying functional DMT1 siRNA, and iron absorption and iron loading were assessed.ResultsLiver, spleen, kidney, heart, and duodenum non‐heme iron levels were decreased in Th3/+ mice lacking intestinal DMT1. Serum non‐heme iron content, serum ferritin levels, and transferrin saturation also decreased in Th3/+ mice lacking intestinal DMT1. Splenomegaly was alleviated in the double KO mice. Oral gavage of GDLVs carrying DMT1 siRNA blunted intestinal DMT1 expression and mitigated hepatic and splenic iron loading. Serum non‐heme iron levels, serum ferritin, and transferrin saturation also decreased in Th3/+ mice receiving GDLVs with DMT1 siRNA.ConclusionIntestinal DMT1 is required for iron‐loading in Th3/+ mice, and in vivo DMT1 knock down is an effective approach to blunt iron loading in mice modeling βTI.

Establishing Dietary Iron Requirements for Mouse and Rat Models of Hereditary Hemochromatosis

The established iron requirement for laboratory rodents is 35‐50 ppm, but standard rodent chows contain up to 350 ppm iron. Excess dietary iron exacerbates iron accumulation in hepcidin (Hamp) knockout (KO) mice and rats, which model the iron‐overload disorder hereditary hemochromatosis (HH) in humans. Establishing iron requirements is important to allow for proper experimental design when studying Hamp KOs since WT littermates are not iron‐loaded (and thus not an appropriate control group for iron‐loaded Hamp KOs). We hypothesized that Hamp KOs have iron requirements at least 50% below those of WT animals, given that intestinal iron absorption is inappropriately elevated (by 2‐3‐fold) in the KOs. In the present study, WT and Hamp KO mice and rats of both sexes were weaned onto one of four AIN‐93G purified rodent diets, with the following iron concentrations (in ppm): 5‐7 (low), 17‐20 (low marginal), 24‐27 (high marginal), or 45‐49 (adequate). After 6 weeks on the diets, bioindicators of iron status were assessed, including blood hemoglobin content and hematocrit, serum ferritin and nonheme iron content, tissue nonheme iron concentration, and blood transferrin saturation. Outcomes showed that significant iron loading occurred in Hamp KO animals when fed the high‐marginal and adequate iron diets, as indicated by higher serum ferritin and nonheme iron content, elevated hepatic iron levels and increased TSAT. Iron loading, however, did not occur when the KO rats and mice were fed the low‐marginal iron diets. Animals fed the low‐iron diet, however, developed IDA. We thus conclude that the optimal amount of dietary iron that will not result in iron loading post‐weaning in Hamp KOs, while also not causing iron depletion, is ~22 ppm. Consistent with our hypothesis then, Hamp KO rodents require about half as much iron as WT controls.

Identifying Monomeric Fe Species for Efficient Direct Methane Oxidation to C1 Oxygenates with H2O2 over Fe/MOR Catalysts

Exploring advanced catalysts and reaction systems operated at mild reaction conditions is crucial for conducting the direct methane oxidation reaction toward oxygenate products. Many efforts have been put into research on pentasil−type (MFI) zeolites based on mononuclear and/or binuclear iron sites, using H2O2 as the oxidant. In this work, we present a modified liquid ion−exchange method to better control Fe loading in a mordenite−type (MOR) zeolite with a Si/Al molar ratio of 9. The optimized Fe/MOR catalyst showed excellent performance in the direct methane oxidation reaction with turnover frequencies (TOFs) of 555 h−1 to C1 oxygenates, significantly better than the reported activity. Multiple comparative experiments were conducted to reveal the mechanism behind the performance. Strikingly, the active sites in the Fe/MOR catalyst were found to be mononuclear iron sites, confirmed by transmission electron microscopy (TEM), ultraviolet−visible diffuse reflectance spectroscopy (UV−vis DRS), and X-ray absorption spectroscopy (XAS). Increasing the iron loading led to the aggregation of the iron sites, which tend to trigger undesirable side reactions (i.e., H2O2 decomposition and over−oxidation), resulting in a significant decrease in TOFs to C1 oxygenates.

Pulmonary Dysfunction in Transfusion-Dependent Thalassemia and Response to Intensive Chelation Therapy

To evaluate pulmonary functions in children with transfusion-dependent thalassemia, and its reversal (lung dysfunction) using intensive intravenous chelation with desferrioxamine (DFO) (4 weeks). This descriptive study enrolled 77 children with transfusion-dependent thalassemia. Pulmonary function test (PFT) and iron load (serum ferritin (SF) andT2* MRI of heart and liver) were done. PFT included spirometry, total lung capacity (TLC) by helium dilution test and diffusion capacity by carbon monoxide (DLCO). Follow-up PFT was available for 13 children with moderate to severe lung dysfunction given intravenous DFO. 50 (68.8%) patients had lung dysfunction, most commonly diffusional impairment (48; 96%), and reduced TLC (11; 22%); and none had obstructive pattern. 9 (81.8%) patients with restrictive defect had moderate to severely deranged DLCO. PFT and T2* MRI values were inversely correlated with serum ferritin. Among 13 patients receiving intensive chelation for 4 weeks, significant improvement was noticed in forced expiratory volume in one minute/ forced vital capacity ratio (DFEV1/FVC) (P=0.009), DDLCO (P=0.006) and DSF (P=0.01). Pulmonary dysfunction is common in children with multi-transfused thalassemia, and routine screening by PFT needs to be part of the management guidelines.

Left atrial deformation indices in β-thalassemia major patients.

The presence of atrial cardiomyopathy in β-thalassemia major (β-TM) patients complicates their clinical condition. The diagnosis is challenging even with cardiac magnetic resonance (CMR) imaging. Novel echocardiographic techniques are applied to increase the diagnostic yield. Fifty-six β-TM patients and thirty age and sex-matched controls were included in the present cross-sectional study. Heart rate, PR duration, and P axis were measured by electrocardiography, left ventricular ejection fraction (LVEF) and end-diastolic diameter (LVEDD), ratio between early mitral inflow velocity and mitral annular early diastolic velocity (E/e'), left atrial volume index (LAVI), left atrial strain at reservoir (LASr), conduit (LAScd) and contraction (LASct) phases respectively, left ventricular global longitudinal strain (GLS) by echocardiography, and T2* calculation in patient group by CMR. PR duration, LVEF, LAVI, E/e', GLS, and left atrial deformation parameters differed between patients and controls (p <0.05). In patient group, left atrial strain was correlated with PR duration, LAVI, E/e', GLS, and T2* (p <0.05). T2* was correlated only with left atrial deformation indices (p <0.05). Patients with a history of atrial fibrillation were older, had lower heart rate, prolonged PR, increased E/e' and LAVI, and impaired left atrial strain (p <0.05). LASct differed relative to the presence of atrial fibrillation and myocardial iron overload. Atrial strain could be of clinical use in the early detection of atrial cardiomyopathy. An impaired LASct could identify β-TM patients with undetected episodes of atrial fibrillation. Finally, left atrial strain may be helpful in myocardial iron load estimation.

Amorphous iron oxides anchored on BiOCl nanoplates as robust catalysts for high-performance photo-Fenton oxidation

Semiconductor supported iron oxides are highly promising catalysts to remove organic pollutants in photo-Fenton. Development of robust composite catalysts with both high activity and stability is essential. In this work, amorphous iron oxide layers are uniformly and tightly anchored on two-dimensional (2D) BiOCl nanoplates through post precipitation-deposition and subsequent low-temperature thermal treatment at 150–350 °C. A low iron loading amount (1–2 wt.%) is sufficient to make the resulted composite (BiOCl-Fe) catalysts superior in photo-Fenton oxidation of phenol (10 mg/L) with high mineralization efficiency (up to about 80% in 60 min). The low-temperature thermal treatment can significantly enhance the stability of catalysts with much less iron leached and high photo-Fenton performance maintained. The intimate contact between the amorphous iron oxide layers and the 2D BiOCl nanoplates could guarantee the fluent electron transfer and efficient activation of H2O2 at interfaces. Compared with the pristine BiOCl, the BiOCl-Fe catalysts possess faster separation of the charge carriers. The predominant active species turns from O2•– in photocatalysis to HO• in the photo-Fenton catalysis. This research could provide enhanced understanding on the synthesis of robust catalysts and the structure optimization of BiOCl supported iron oxides for photo-Fenton.

Sugarcane Bagasse Ash as a Catalyst Support for Facile and Highly Scalable Preparation of Magnetic Fenton Catalysts for Ultra-Highly Efficient Removal of Tetracycline

Sugarcane bagasse ash, which is waste from the combustion process of bagasse for electricity generation, was utilized as received as a catalyst support to prepare the magnetic sugarcane bagasse ash (MBGA) with different iron-to-ash ratios using a simple co-precipitation method, and the effects of NaOH and iron loadings on the physicochemical properties of the catalyst were investigated using various intensive characterization techniques. In addition, the catalyst was used with a low amount of H2O2 for the catalytic degradation of a high concentration of tetracycline (800 mg/L) via a Fenton system. The catalyst exhibited excellent degradation activity of 90.43% removal with good magnetic properties and high stabilities and retained good efficiency after four cycles with NaOH as the eluent. Moreover, the hydroxyl radical on the surface of catalyst played a major role in the degradation of TC, and carbon-silica surface of bagasse ash significantly improved the efficiencies. The results indicated that the MBGA catalyst shows the potential to be highly scalable for a practical application, with high performance in the heterogeneous Fenton system.

Fresh biomass derived biochar with high-load zero-valent iron prepared in one step for efficient arsenic removal

Biochar composites, as a kind of common adsorption and purification materials, are usually prepared by carbonizing biomass firstly and then loading with adsorbent. In this study, an innovative facile one-step pyrolysis-loading process was proposed to synthesize a magnetic high-loading zero-valent iron/biochar composite (BC-ZVI) directly from fresh bamboo immersed with FeCl3 solution. Based on fresh biomass, the BC-ZVI composites have an iron load of 18.5%–30.9% and a well-defined nanoporous structure, providing abundant active sites for interface-related processes. Experiments show that BC-ZVI is effective for removing As(III) and As(V) in a wide pH range and in the presence of competing ions. The adsorption capacity of BC-ZVI reaches 129.24 mg g−1 for As(III) and 127.15 mg g−1 for As(V), respectively. The adsorption mechanism was explored and discussed basing on the detailed spectroscopy analysis. Additionally, BC-ZVI showed favorable magnetic recovery and reusability in different water matrix, which demonstrates a potential candidate in removing arsenic from environment water. The proposed fresh biomass-derived one-step pyrolysis-loading approach could inspire low-cost and facile production of functional biochar composites.

Kinetics study of catalytic wet oxidation of phenol over novel ceria promoted mesoporous silica supported Ru-Fe3O4 catalyst

A novel catalyst was synthesized via excess solution impregnation (ESI) of Ru and Fe3O4 nanoparticles (NPs) on ceria-loaded mesoporous SiO2 and mesoporous SiO2 was synthesized using sol-gel method. Degradation of phenol and effluent containing phenol from resin industry was performed over Ru-Fe3O4/CeOx-SiO2 (Ce3+/Ce4+, x = 1.64) catalyst in an autoclave reactor at 423 K and 14 bar oxygen pressure. Effective phenol degradation of 95% for the model aqueous solution of phenol and 92% for industrial effluent containing phenol were achieved when the both ruthenium and iron loadings were 0.25 wt% under optimized reaction conditions. The close contact between ruthenium and Fe3O4 nanoparticles facilitated the oxidation of phenol at very low temperature, whereas ceria NPs act as a promoter for oxidation reaction. The kinetics insights of oxidation reaction were studied and the catalysts were characterized thoroughly using BET, TPD, XRD, SEM, HR- TEM, ICP-AES, XPS and CO chemisorptions techniques. High surface area and large mesopores of silica facilitated the fine dispersion of the active catalytic sites and oxygen vacancy as supported by the DFT study for catalytic activity. Optimal process conditions could render much higher phenol degradation efficacy in comparison with previous scientific investigations.

Absorbing oxygen carrier induces phosphorus enrichment in sludge: Preparation and screening

Phosphorus recovery from sludge is considered a feasible approach. By combining the oxygen carrier gasification technology and microwave heating, an absorbing oxygen carrier (AOC) is used in this study to successfully induce phosphorus enrichment in sludge char. The AOC, which is based on iron and supported on SiC, has been prepared via ultrasonic impregnation. The effects of preparation conditions (particle size of SiC and loading of iron) on the phosphorus enrichment characteristics, thermal reaction performance of the AOC and sludge, and the wave absorption performance of the AOC were investigated. The results show that the AOC prepared using a SiC particle size of 36 mesh and iron loading of 10% can achieve a phosphorus enrichment of 91.30% in the sludge char when the temperature of the microwave reactor is 600 °C. In the thermal reaction test, AOC can effectively increase the rate and depth of sludge gasification reaction in the medium- and high-temperature reaction stages. Iron-based is loading on the SiC surface and has a good wave absorption performance (RL = -16.28 dB; effective absorption width is 3.54 GHz). Overall, this study provides a new and effective approach for utilizing sludge.

Hydrothermally assisted synthesis of nano zero-valent iron encapsulated in biomass-derived carbon for peroxymonosulfate activation: The performance and mechanisms for efficient degradation of monochlorobenzene

A facile, green and easily-scalable method of synthesizing stable and effective nano zero-valent iron (nZVI)‑carbon composites for peroxymonosulfate (PMS) activation was highly desirable for in-situ groundwater remediation. This study developed a two-step hydrothermally assisted carbothermal reduction method to prepare nZVI-encapsulated carbon composite (Fe@C) using rice straw and ferric nitrate as precursors. The hydrothermal reactions were conducive to iron loading, and carbothermal temperature was crucial for the aromatization and graphitization of hydrothermal carbonaceous products, the reductive transformation of iron oxides into nZVI and the development of porous structure in composites. At carbothermal temperature of 800 °C following hydrothermal reactions, the stable Fe@C800 with nZVI encapsulated in the spherical carbon shell was obtained and exhibited the best catalytic performance for PMS activation and the degradation of monochlorobenzene (MCB) in a wide range of pH values (3−11) with removal efficiency after 120 min reaction and first-order kinetic rate constant (k1) of 98.7% and 0.087 min−1 respectively under the optimum conditions of 10 mM PMS and 0.2 g·L−1 Fe@C800. The inhibiting effects of common co-existed anions (i.e., Cl−, HCO3− and H2PO4−) and humic acid in groundwater on the removal of MCB in Fe@C800/PMS system was also investigated. Both OH-dominated radical processes and nonradical pathways involving 1O2 and surface electron transfers were accounted for PMS activation and MCB removal. The inner nZVI was protected by the carbon shell, endowing Fe@C800 with high reactivity and good reusability. Additionally, 81.2% and 73.5% of MCB removal rates were achieved in tap water and actual contaminated groundwater respectively. This study not only provided a novel strategy to synthesize highly effective and stable nZVI‑carbon composites using the agricultural biomass waste for PMS induced oxidation of organic contaminants in groundwater, but also enhanced the understanding on the activation mechanism of iron‑carbon based catalysts towards PMS.

Iron, hepcidin, and microcytosis in canine hepatocellular carcinoma.

Erythrocyte microcytosis in some dogs with hepatocellular carcinoma (HCC) suggests a derangement in systemic iron. Hepcidin, the master regulator of iron, is secreted by the liver in response to interleukin 6 (IL-6) and/or bone morphogenetic protein 6 (BMP6) and can cause microcytosis. Pilot study to compare the quantities of hepcidin, IL-6, and BMP6 RNA molecules in archival tumoral (HCC) and adjacent peritumoral (non-HCC) hepatic tissue to determine if they are different between tissue types or associated with microcytosis. RNA was isolated from formalin-fixed, paraffin-embedded HCC and non-HCC tissue from seven microcytic dogs and four normocytic dogs. Digital RNA counts of hepcidin, IL-6, or BMP6, and six other iron-regulatory genes were determined using the Nanostring nCounter system. The area of blue on each section was digitally evaluated to measure the extent of Prussian blue staining objectively. Parameters were compared between HCC and non-HCC tissue and between microcytic and normocytic groups. Hepcidin was decreased, and transferrin receptor 1 (TfR1) was increased in HCC tissue compared with non-HCC tissue. Non-HCC hepcidin RNA counts correlated negatively with MCV and positively with the extent of iron staining. Hepcidin expression was higher in non-HCC tissue of microcytic cases than in normocytic cases. Canine HCC cases showed relatively increased iron staining in non-HCC tissue and decreased hepcidin RNA in HCC tissue. Microcytic cases had higher hepcidin RNA in non-HCC tissue than normocytic cases. Future studies may extend these findings to protein quantification, cellular localization of RNA changes, and determining if iron loading in canine liver is a predisposing factor for HCC.

Exploratory Study of Superparamagnetic Iron Oxide Dose Optimization in Breast Cancer Sentinel Lymph Node Identification Using a Handheld Magnetic Probe and Iron Quantitation.

Simple SummarySentinel lymph node biopsy (SLNB) using super magnetic iron oxide (SPIO) and magnetic probes is expected to be a simple and safe method of detecting cancerous lymph nodes without using radioisotopes (RIs). A multicenter trial of SLNB was conducted using a handheld magnetic probe and SPIO (Rizobist®) and its non-inferiority with the conventional RI method. The quantity of iron in SLN was measured to examine the necessary dosage and administration method for sufficient SLN detection in the case of this test. Further, a clinical trial was conducted to determine the possibility of SLNB with a half-dose of SPIO (1.0 mL → 0.5 mL), and the resulting iron volume measured at that time was also examined. This study demonstrates that sufficient iron content reaches SLN even at an SPIO dose of 0.5 mL.This exploratory study compared doses of ferucarbotran, a superparamagnetic iron oxide nanoparticle, in sentinel lymph nodes (SLNs) and quantified the SLN iron load by dose and localization. Eighteen females aged ≥20 years scheduled for an SLN biopsy with node-negative breast cancer were divided into two equal groups and administered either 1 mL or 0.5 mL ferucarbotran. Iron content was evaluated with a handheld magnetometer and quantification device. The average iron content was 42.8 µg (range, 1.3–95.0; 0.15% of the injected dose) and 21.9 µg (1.1–71.0; 0.16%) in the 1-mL and 0.5-mL groups, respectively (p = 0.131). The iron content of the closest SLN compared to the second SLN was 53.0 vs. 10.0 µg (19% of the injected dose) and 34.8 vs. 4.1 µg (11.1%) for the 1-mL and 0.5-mL groups, respectively (p = 0.001 for both). The magnetic field was high in both groups (average 7.30 µT and 6.00 µT in the 1-mL and 0.5-mL groups, respectively) but was not statistically significant (p = 0.918). The magnetic field and iron content were correlated (overall SLNs, p = 0.02; 1-mL, p = 0.014; 0.5-mL, p = 0.010). A 0.5-mL dose was sufficient for SLN identification. Primary and secondary SLNs could be differentiated based on iron content. Handheld magnetometers could be used to assess the SLN iron content.

Relaxivity properties of magnetoferritin: The iron loading effect

Self-assembling ferritin protein cages have been used as a template for magnetic iron oxide nanoparticle synthesis within its 8nm cavity to be explored as a potential magnetic resonance imaging contrast agent. Here in, magnetic nanocores with various iron content were successfully synthesized using recombinant human H-chain ferritin (HFn) by a controlled mineralization reaction. r1 and r2 relaxivities of the synthesized magnetoferritin nanoparticles were measured and the effect of iron loading factor on the r1 and r2 relaxivity was investigated by using a quite large range of 10 different iron loadings per protein cage (500-5000) at 90MHz and 300MHz. The sample with the highest iron loading of 5329 Fe/cage has r2 value of 165.2mM-1s-1 and r1 value of 1.98mM-1s-1 at 300MHz. This high r2 value together with a very low protein and iron concentrations (0.03-0.2mg/mL and 0.15mM, respectively) renders magnetoferritin very effective T2 contrast agents. However, r1 values were found to be smaller than literature values suggesting that magnetoferritin may not serve as T1 contrast agent in MRI. Moreover, magnetoferritin showed an increase in r2 relaxivity with the iron loadings while r1 values have not been affected by the number of Fe atoms loaded as much as r2 values. This result also sheds light on understanding the formation mechanism of iron oxide core and its contribution on relaxation in MRI.

The (Bio)Chemistry of Non-Transferrin-Bound Iron.

In healthy individuals, virtually all blood plasma iron is bound by transferrin. However, in several diseases and clinical conditions, hazardous non-transferrin-bound iron (NTBI) species occur. NTBI represents a potentially toxic iron form, being a direct cause of oxidative stress in the circulating compartment and tissue iron loading. The accumulation of these species can cause cellular damage in several organs, namely, the liver, spleen, and heart. Despite its pathophysiological relevance, the chemical nature of NTBI remains elusive. This has precluded its use as a clinical biochemical marker and the development of targeted therapies. Herein, we make a critical assessment of the current knowledge of NTBI speciation. The currently accepted hypotheses suggest that NTBI is mostly iron bound to citric acid and iron bound to serum albumin, but the chemistry of this system remains fuzzy. We explore the complex chemistry of iron complexation by citric acid and its implications towards NTBI reactivity. Further, the ability of albumin to bind iron is revised and the role of protein post-translational modifications on iron binding is discussed. The characterization of the NTBI species structure may be the starting point for the development of a standardized analytical assay, the better understanding of these species’ reactivity or the identification of NTBI uptake mechanisms by different cell types, and finally, to the development of new therapies.

Poly(rC)-binding protein 1 represses ferritinophagy-mediated ferroptosis in head and neck cancer

A cytosolic iron chaperone poly(rC)-binding protein 1 (PCBP1) is a multifunctional RNA-binding protein involving gene transcription, RNA regulation, and iron loading to ferritins. PCBP1 is also known to repress autophagy, but the role of PCBP1 in ferritinophagy and ferroptosis remains unrevealed. Therefore, we examined the role of PCBP1 in ferritinophagy-mediated ferroptosis in head and neck cancer (HNC) cells. The effects of system xc– cystine/glutamate antiporter (xCT) inhibitors and PCBP1 gene silencing/overexpression were tested on HNC cell lines and mouse tumor xenograft models. These effects were analyzed by assessing cell viability and death, lipid reactive oxygen species and iron production, lipid, malondialdehyde, mRNA/protein expression, and autophagy flux assays. Interaction between PCBP1 and BECN1 mRNA was also examined by luciferase and RNA-protein pull-down assays. PCBP1 gene silencing increased autophagosome generation and autophagic flux. Conversely, PCBP1 upregulation inhibited autophagy activation via direct binding to the CU-rich elements on the 3′-untranslated region (3′-UTR) of BECN1 mRNA. The internal deletion or mutation of the 3′-UTR F2 region recovered BECN1 mRNA stability repressed by PCBP1, resulting in enhanced ferritinophagy-mediated ferroptosis. Besides, PCBP1 knockdown promoted polyunsaturated fatty acid peroxidation by increasing ALOX15 expression. Further, excess iron accumulation caused mitochondrial dysfunction in PCBP1-suppressed cells. A ferroptosis inducer sulfasalazine significantly suppressed tumor growth in mice with the transplantation of PCBP1-silenced HNC. Our data suggest that the dual functions of PCBP1 repressing BECN1 and ALOX15 mRNAs contribute to attenuating cancer susceptibility to ferroptosis inducers.

Iron Chelators, Such as Deferasirox, When Combined With Hydroxyurea, Provide an Additional Benefit of Iron Chelation in Patients Receiving Chronic Transfusion Therapy

Red blood cell (RBC) transfusions have been established as one of the primary therapies in treating sickle cell anemia. However, they are not free of side effects, with overloading the body with iron being one of the most important. Iron chelation therapy greatly reduces the iron load of the body. In addition, hydroxyurea (HU), an oral chemotherapeutic drug also has a significant role in the treatment of the disease with beneficial effects on many of the clinical problems that arise, mainly in reducing painful crises. The aim of this study was to investigate the effect of synergistic transfusion therapy and HU on the response to deferasirox (DFX) chelation therapy. Eighteen patients with sickle cell disease were divided into two groups based on their treatment, either with simple transfusions and DFX or with a combination of transfusion therapy, DFX and HU, and were evaluated with magnetic resonance imaging (MRI) for liver iron concentration (LIC) and biochemistry. All patients completed the study. The results of the study showed improvement in serum ferritin (FER) levels and LIC after 12 months of therapy in both groups, especially in the group receiving the combination therapy with HU. In addition, there was a noteworthy improvement in serum glutamic-oxaloacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT) and lactate dehydrogenase (LDH) levels with serum creatinine (Cr) levels remaining stable during the study in both groups. Hydroxyurea, when combined with iron chelators such as DFX, provides an additional benefit of iron chelation in patients receiving chronic transfusion therapy.

Tetrahydrofuran aided self-assembly synthesis of nZVI@gBC composite as persulfate activator for degradation of 2,4-dichlorophenol

• nZVI@gBC were synthesized by one-step carbothermal reduction method aided by Tetrahydrofuran. • The formation of graphene nano-shells greatly enhanced the stability of nZVI in the air environment. • The nZVI@gBC exhibited superior degradation performance to 2,4-DCP by activating PS. • Four active free radicals (SO 4 •− , •OH, O 2 •− and 1 O 2 ) were produced and participated in the degradation of 2,4-DCP. The defects of easy agglomeration and oxidation of nano zero valent iron (nZVI) limit its large-scale application in industry, especially in the field of environmental remediation. In this study, the iron nanoparticles encapsulated by graphene nano-shells which anchored on the surface of carbon substrate (nZVI@gBC) were synthesized by a one-step carbothermal reduction method aided by Tetrahydrofuran. When the mass ratio of carbon source to iron source is 2:3 and the carbothermic reduction temperature is 700 °C, stabilized nZVI @gBC can be successfully synthesized with a high iron loading rate of 32.5%. The multilayer graphene shell can effectively prevent the rapid passivation and agglomeration of the nZVI core, and the electronic interaction between the iron nanoparticles core and the graphene carbon shell further enhances the catalytic activity and stability of nZVI@gBC. Therefore, due to the unique structure of graphene nano-shells, nZVI@gBC can be stably stored in the air for more than 80 days. In addition, nZVI@gBC exhibited superior catalytic activity in the experiment of removing 2,4-dichlorophenol (2,4-DCP) in groundwater as a persulfate activator. Notably, both the electron paramagnetic resonance (EPR) and quenching tests showed that SO 4 •− , •OH, O 2 •− and 1 O 2 were both involved in the degradation process of 2,4-DCP, and SO 4 •− were the major active species. Simultaneously, three possible degradation pathways of 2,4-DCP were deduced by GC/MS, which were caused by dechlorination, dehydrogenation or carbon–carbon bond cleavage under the attack of SO 4 •− , •OH, O 2 •− and 1 O 2 . Besides, nZVI@gBC can use the dissolved oxygen in the liquid to generate hydroxyl radicals to effectively remove 2,4-DCP without persulfate. This kind of multifunctional nZVI@gBC may become a promising iron-carbon catalyst for large-scale applications in the field of environmental remediation.

Shotgun and TMT-Labeled Proteomic Analysis of the Ovarian Proteins of an Insect Vector, Aedes aegypti (Diptera: Culicidae).

Aedes aegypti [Linnaeus in Hasselquist; yellow fever mosquito] transmits several viruses that infect millions of people each year, including Zika, dengue, yellow fever, chikungunya, and West Nile. Pathogen transmission occurs during blood feeding. Only the females blood feed as they require a bloodmeal for oogenesis; in the bloodmeal, holo-transferrin and hemoglobin provide the females with a high iron load. We are interested in the effects of the bloodmeal on the expression of iron-associated proteins in oogenesis. Previous data showed that following digestion of a bloodmeal, ovarian iron concentrations doubles by 72 hr. We have used shotgun proteomics to identify proteins expressed in Ae. aegypti ovaries at two oogenesis developmental stages following blood feeding, and tandem mass tag-labeling proteomics to quantify proteins expressed at one stage following feeding of a controlled iron diet. Our findings provide the first report of mosquito ovarian protein expression in early and late oogenesis. We identify proteins differentially expressed in the two oogenesis development stages. We establish that metal-associated proteins play an important role in Ae. aegypti oogenesis and we identify new candidate proteins that might be involved in mosquito iron metabolism. Finally, this work identified a unique second ferritin light chain subunit, the first reported in any species. The shotgun proteomic data are available via ProteomeXchange with identifier PXD005893, while the tandem mass tag-labeled proteomic data are available with identifier PXD028242.