2D MoS2 Nanosheets Induce Ferroptosis by Promoting NCOA4-Dependent Ferritinophagy and Inhibiting Ferroportin

The exposure of MoS₂ nanosheets can cause cytotoxicity, which causes health risks and affects its medical applications. However, knowledge of the underlying molecular mechanisms remains limited. This study reports that MoS₂ nanosheets induces ferroptosis in vivo and in vitro, which is caused by the nanosheet themselves rather than by the dissolved ions. MoS₂ nanosheets induce ferroptosis in epithelial (BEAS-2B) and macrophage (RAW264.7) cells due to nuclear receptor coactivator 4 (NCOA4)-dependent excusive ferritinophagy and the inhibition of ferroportin-1 (FPN). In this process, most of the MoS₂ nanosheets enter the cells via macropinocytosis and are localized to the lysosome, contributing to an increase in the lysosomal membrane permeability. At the same time, NCOA4-dependent ferritinophagy is activated, and ferritin is degraded in the lysosome, which generates Fe²⁺.Fe²⁺ leaks into the cytoplasm, leading to ferroptosis. Furthermore, the inhibition of FPN further aggravates the overload of Fe²⁺ in the cell. It has also been observed that ferroptosis is increased in lung tissue in mouse models exposed to MoS₂ nanosheets. This work highlights a novel mechanism by which MoS₂ nanosheets induce ferroptosis by promoting NCOA4-dependent ferritinophagy and inhibiting FPN, which could be of importance to elucidate the toxicity and identify the medical applications of 2D nanoparticles.     

Intranasal Nanovaccine Confers Homo‐ and Hetero‐Subtypic Influenza Protection

Cross‐protective and non‐invasively administered vaccines are attractive and highly desired for the control of influenza. Self‐assembling nanotechnology provides an opportunity for the development of vaccines with superior performance. In this study, an intranasal nanovaccine is developed targeting the conserved ectodomain of influenza matrix protein 2(M2e). 3‐sequential repeats of M2e (3M2e) is presented on the self‐assembling recombinant human heavy chain ferritin (rHF) cage to form the 3M2e‐rHF nanoparticle. Intranasal vaccination with 3M2e‐rHF nanoparticles in the absence of an adjuvant induces robust immune responses, including high titers of sera M2e‐specific IgG antibodies, T‐cell immune responses, and mucosal secretory‐IgA antibodies in mice. The 3M2e‐rHF nanoparticles also confer complete protection against a lethal infection of homo‐subtypic H1N1 and hetero‐subtypic H9N2 virus. An analysis of the mechanism of protection underlying the intranasal immunization with the 3M2e‐rHF nanoparticle indicates that M2e‐specific mucosal secretory‐IgA and T‐cell immune responses may play critical roles in the prevention of infection. The results suggest that the 3M2e‐rHF nanoparticle is a promising, needle‐free, intranasally administered, cross‐protective influenza vaccine. The use of self‐assembling nanovaccines could be an ideal strategy for developing vaccines with characteristics such as high immunogenicity, cross‐protection, and convenient administration, as well as being economical and suitable for large‐scale production.     

Expression and Iron Storage Properties of Recombinant Human Ferritins in Escherichia Coli: Relevance for Functional Ferritins in Food Systems

Ferritin is an iron storage protein found in most living organisms. Human heavy chain (H-) and light chain (L-) ferritin were amplified from human heart cDNA library. Each ferritin gene was inserted down stream of the T7 promoter of bacterial expression, and finally four types of H-, L-, and co-expression vectors were constructed. Recombinant human ferritins were overexpressed and identified with SDS-PAGE and western blotting. The expression levels of recombinant ferritin proteins ranged about 29–36% of whole cell total protein. From atomic absorption spectrometry (AAS) analysis, the rate of iron uptake for H-ferritin was significantly faster than that for the HL-, LH-, and L‐ferritin, respectively. From AAS analysis, the levels of iron content in cells progressively increased in transformants with 0–30 mM ferric citrate in the media. Among these ferritin transformants, the highest amount of cellular iron was observed with H‐ferritin transformant. The total amounts of iron content in E. coli could be sequentially ranked as H-ferritin > HL-ferritin > LH-ferritin > L-ferritin > negative transformants. Expressed recombinant human ferritins indicated that their assembled subunits were able to store iron in the cells. The results of this study further enhances our understanding of iron uptake properties in vivo and suggest similar strategies for using food-grade ferritins for functional foods or iron-fortified food ingredients.     

Sequence,Expression, and Anti-GCRV Function of the Ferritin from the Grass Carp,Ctenopharyngodon idellus

Ferritin possesses an immune function to defend against pathogen infection. To elucidate the immunity-protecting roles of ferritin from Ctenopharyngodon idellus (Ciferritin) against virus infection, the cDNA and promoter sequences of Ciferritin were determined, and the correlations between Ciferrtin expressions and promoter methylation levels were analyzed. In addition, the functional role of Ciferrtin on GCRV (grass carp reovirus) infection was assessed. The full-length cDNA of Ciferritin is 1053 bp, consists of a 531 bp open-reading frame, and encodes 176 amino acids. Ciferritin showed the highest sequence identity with the ferritin middle subunit of Mylopharyngodon piceus (93.56%), followed by the subunits of Megalobrama amblycephala and Sinocyclocheilus rhinocerous. Ciferritin contains a conserved ferritin domain (interval: 10–94 aa), and the caspase recruitment domain (CARD) and Rubrerythrin domain were also predicted. In the spleen and kidney, significantly higher Ciferritin expressions were observed at 6, 12, 24, or 168 h post GCRV infection than those in the PBS injection group (p < 0.05). The Ciferrtin expression level in the progeny of maternal-immunized grass carp was significantly higher than that in the progeny of common grass carp (p < 0.05). Ciferritin promoter methylation level in the progeny from common grass carp was 1.27 ± 0.15, and in the progeny of the maternal-immunized group was 1.00 ± 0.14. In addition, methylation levels of “CpG9” and “CpG10” loci were significantly lower in the progeny of maternal-immunized fish than those in the common group. Except for the “CpG5”, methylation levels of all other detected “CpG” loci negatively correlated with Ciferritin expression levels. Furthermore, the total methylation level of “CpG1–10” negatively correlated with the Ciferritin expressions. The Ciferritin expression level was significantly up-regulated, and the VP7 protein levels were significantly reduced, at 24 h post GCRV infection in the Ciferritin over-expression cells (p < 0.05). The results from the present study provide sequence, epigenetic modification and expression, and anti-GCRV functional information of Ciferritin, which provide a basis for achieving resistance to GCRV in grass carp breeding.     

Circulating Levels of Ferritin,RDW, PTLs as Predictive Biomarkers of Postoperative Atrial Fibrillation Risk after Cardiac Surgery in Extracorporeal Circulation

Postoperative atrial fibrillation (POAF) is the most common arrhythmia after cardiac surgery in conventional extracorporeal circulation (CECC), with an incidence of 15–50%. The POAF pathophysiology is not known, and no blood biomarkers exist. However, an association between increased ferritin levels and increased AF risk, has been demonstrated. Based on such evidence, here, we evaluated the effectiveness of ferritin and other haematological parameters as POAF risk biomarkers in patients subjected to cardiac surgery. We enrolled 105 patients (mean age = 70.1 ± 7.1 years; 70 men and 35 females) with diverse heart pathologies and who were subjected to cardiothoracic surgery. Their blood samples were collected and used to determine hematological parameters. Electrocardiographic and echocardiographic parameters were also evaluated. The data obtained demonstrated significantly higher levels of serum ferritin, red cell distribution width (RDW), and platelets (PLTs) in POAF patients. However, the serum ferritin resulted to be the independent factor associated with the onset POAF risk. Thus, we detected the ferritin cut-off value, which, when ≥148.5 ng/mL, identifies the subjects at the highest POAF risk, and with abnormal ECG atrial parameters, such as PW indices, and altered structural heart disease variables. Serum ferritin, RDW, and PTLs represent predictive biomarkers of POAF after cardiothoracic surgery in CECC; particularly, serum ferritin combined with anormal PW indices and structural heart disease variables can represent an optimal tool for predicting not only POAF, but also the eventual stroke onset.     

铁蛋白纳米粒子的修饰及细胞内化特性的研究

通过基因工程的方法将人表皮生长因子(EGF)和TAT分别修饰于FTH1亚基的N端,采用原核表达系统可获得EGFR靶向修饰的铁蛋白重链亚基蛋白(EGF∷FTH1)和修饰有穿膜肽的铁蛋白重链亚基蛋白(TAT∷FTH1)。随后,将变性的EGF∷FTH1与TAT∷FTH1以一定比例混合进行复性得到TAT/EGF-FTH1双功能化的纳米粒子。荧光显微镜的结果表明,TAT的修饰能有效增强纳米粒子的内化效果。     

A Conserved Tyrosine in Ferritin Is a Molecular Capacitor

A highly conserved tyrosine residue of unknown function is present in the vicinity of the di‐iron catalytic center of the ubiquitous iron‐storage protein ferritin. The di‐iron center with a gateway Fe^II/Fe^III‐binding site nearby provides the vital iron‐storage mechanism of the protein. It is believed that, in eukaryotic ferritin, this center catalyzes simultaneous oxidation of two Fe^II ions, whereas in microbial ferritin it catalyzes simultaneous oxidation of three Fe^II ions. To understand the role of the conserved tyrosine, we studied the intermediates and products that are formed during catalysis of Fe^II oxidation in the di‐iron catalytic centers of the hyperthermophilic archaeal Pyrococcus furiosus ferritin and of eukaryotic human H ferritin. Based on our spectroscopic studies and modeling, we propose a merger of the models for eukaryotic and bacterial ferritin into a common mechanism of Fe^II oxidation in which the conserved tyrosine acts as a single‐electron molecular capacitor to facilitate oxidation of Fe^II.     

Quality assessment of corn snacks enriched with soybean ferritin among young healthy people and patient with Crohn’s disease: the effect of extrusion conditions

Fortified extruded snacks are convenient products to supplement malnourished patients’ diet, e.g. suffering from Crohn’s disease. The snacks were extruded with different additions of iron-biofortified sprouts under varying process conditions (temperature and humidity). The sensory profiling showed the correlation between extrusion temperature and snack stickiness (R = 0.835), crispiness (R = 0.727), hardness (R=−0.485), as well as the intensity of corn (R = 0.888), powder (R=−0.795), metallic (R=−0.606) and bitter (R=−0.901) tastes. The sprouts addition affected metallic taste (R = 0.606) and aroma (R = 0.666) intensity. The product desirability was compared between healthy people (HP) and Crohn’s patients (CP). Overall desirability positively correlated with taste desirability in both groups. In the HP group, taste desirability was associated with metallic taste (R=−0.857) and Fe(III) content (R=−0.717). Also, aroma desirability (connected with pyrazines) was more significant to HP. Higher tolerance of CP to metallic and bitter flavours was observed. This confirms that the taste and aroma preferences of CP and HP are different.