Expression of clMagR/clCry4 protein in mBMSCs provides T2-contrast enhancement of MRI.

Here, we propose for the first time the evaluation of magnetosensitive clMagR/clCry4 as a magnetic resonance imaging (MRI) reporter gene that imparts sensitivity to endogenous contrast in eukaryotic organisms. Using a lentiviral vector, we introduced clMagR/clCry4 into C57BL/6 mice-derived bone marrow mesenchymal stem cells (mBMSCs), which could specifically bind with iron, significantly affected MRI transverse relaxation, and generated readily detectable contrast without adverse effects in vivo. Specifically, clMagR/clCry4 makes mBMSCs beneficial for enhancing the sensitivity of MRI-R2 for iron-bearing granules, in which cells recruit exogenous iron and convert these stores into an MRI-detectable contrast; this is not achievable with control cells. Additionally, Prussian blue staining was performed together with ultrathin cell slices to provide direct evidence of natural iron-bearing granules being detectable on MRI. Hence, it was inferred that the sensitivity of MRI detection should be correlated with clMagR/clCry4 and exogenous iron. Taken together, the clMagR/clCry4 has great potential as an MRI reporter gene. STATEMENT OF SIGNIFICANCE: In this study, we propose the evaluation of magnetosensitive clMagR/clCry4 as an MRI reporter gene, imparting detection sensitivity to eukaryotic mBMSCs for endogenous contrast. At this point, the clMagR and clCry4 were located within the cytoplasm and possibly influence each other. The clMagR/clCry4 makes mBMSCs beneficial for enhancing the sensitivity of MRI-R2 for iron-bearing granules, in which protein could specifically bind with iron and convert these stores into MRI-detectable contrast; this is not achieved by control cells. The viewpoint was speculated that the clMagR/clCry4 and exogenous iron were complementary to each other. Additionally, Prussian blue staining was performed together with TEM observations to provide direct evidence that the iron-bearing granules were sensitive to MRI.

Multiscale Multimodal Investigation of the Intratissural Biodistribution of Iron Nanotherapeutics with Single Cell Resolution Reveals Co-Localization with Endogenous Iron in Splenic Macrophages.

Imaging of iron-based nanoparticles (NPs) remains challenging because of the presence of endogenous iron in tissues that is difficult to distinguish from exogenous iron originating from the NPs. Here, an analytical cascade for characterizing the biodistribution of biomedically relevant iron-based NPs from the organ scale to the cellular and subcellular scales is introduced. The biodistribution on an organ level is assessed by elemental analysis and quantification of magnetic iron by electron paramagnetic resonance, which allowed differentiation of exogenous and endogenous iron. Complementary to these bulk analysis techniques, correlative whole-slide optical and electron microscopy provided spatially resolved insight into the biodistribution of endo- and exogenous iron accumulation in macrophages, with single-cell and single-particle resolution, revealing coaccumulation of iron NPs with endogenous iron in splenic macrophages. Subsequent transmission electron microscopy revealed two types of morphologically distinct iron-containing structures (exogenous nanoparticles and endogenous ferritin) within membrane-bound vesicles in the cytoplasm, hinting at an attempt of splenic macrophages to extract and recycle iron from exogenous nanoparticles. Overall, this strategy enables the distinction of endo- and exogenous iron across scales (from cm to nm, based on the analysis of thousands of cells) and illustrates distribution on organ, cell, and organelle levels.

[Effects of Iron Intensity-regulated Root Microbial Community Structure and Function on Cadmium Accumulation in Rice].

Exploring the effects of exogenous iron (Fe) on cadmium (Cd) in rice is of great significance for ensuring food security. The accumulation of Cd and the changes in the microbial community structure in rice roots under three Fe concentrations (5, 50, and 500 µmol·L-1 EDTA-Na2Fe) were studied through a hydroponic experiment. The results showed that the increase in the environmental Fe concentration promoted the formation of iron plaque on the rice roots, and both Fe-deficiency and Fe-sufficiency would enhance the adsorption and fixation of Cd on the root surface. Compared with that of normal Fe levels (50 µmol·L-1), Fe deficiency increased Cd accumulation in rice roots and shoots by 49.76% and 15.68%, respectively. Although Fe sufficiency also increased Cd accumulation in the roots by 18.39%, the Cd concentration in shoots was significantly reduced by 35.95% compared with that of the normal Fe. 16S rRNA high-throughput sequencing was used to determine the root microbial community structure, and through PCA, LEfSe, and RDA analysis, it was found that compared with normal Fe, an Fe-deficient environment reduced the abundance and uniformity of root microbes. Proteobacteria and Bacteroidetes at the phylum level were the dominant flora, Fe deficiency inhibited the increase in the relative abundance of Bacteroidetes, and high-concentration Fe reduced the relative abundance of Proteobacteria. At the genus level, the relative abundance of functional microorganisms Ensifer, Rhodopila, Bdellovibrio, and Dyella were different under different Fe environments, which may have affected the absorption and accumulation of Cd by rice by affecting the formation of Fe plaque on the root and other biochemical processes. In addition, the effect of an Fe-deficient environment on microbial functions was higher than that of the Fe sufficient environment. This study investigated the changes in the rice root microbial community structure and the ability of rice to absorb and transport Cd under different Fe environments, which provided a theoretical basis and an important reference for the inhibition of Fe on Cd accumulation in rice in Cd-polluted paddy soil in southern China.

Ferroptosis-induced effect and mechanism of dihydroartemisinin on tumor cells / 中草药

Objective: To explore the effect and mechanism of dihydroartemisinin (DHA) in inducing ferroptosis of tumor cells. Methods: 3,3',5,5'-Tetramethylbenzidine was used to detect the oxygen free radicals (•OH) formed by DHA and FeSO4 in vitro. The cytotoxicity of DHA on HepG2 cells was detected by MTT method (including FeSO4 or deferoxamine pretreated groups). MTT assay was used to investigate the influence of glutathione (GSH) and inhibitor (Fer-1) on cytotoxicity of DHA; DCFH-DA dye was used to investigate intracellular reactive oxygen species induced by DHA (including FeSO4 pretreated groups). C11-BODIPY581/591 and DiO dye were used to examine the influence of DHA (including FeSO4 pretreated groups) on intracellular lipid peroxide formation and cell membrane structure; Glutathione peroxidase assay kit was used to explore the influence of DHA (including FeSO4 pretreated groups) on intracellular activity GPX-4 in HepG2 cells. Results: Fenton-like reaction occurred between DHA and Fe2+, and •OH was produced during the reaction. The half-inhibitory concentration (IC50) of DHA was (39.96 ± 8.78) μmol/L. FeSO4 and deferoxamine could increase or decrease the cytotoxicity of DHA, respectively. After treated with DHA, the intracellular content of reactive oxygen species and lipid peroxide was increased, the cell morphology became larger, and the cell membrane was broken. Compared with the DHA treated group, the FeSO4 pretreated group further increased the intracellular reactive oxygen species and lipid peroxide content, and the cell membrane morphology was completely destroyed. FeSO4 could also enhance the inhibitory effect of DHA on GPX-4 activity. Conclusion: DHA increases intracellular reactive oxygen species through Fenton-like reaction and ultimately induces ferroptosis of tumor cells. In addition, exogenous iron can accelerate the Fenton-like reaction of DHA and accelerate the occurrence and development of ferroptosis of tumor cells.

Iron bioavailability from supplemented formula milk: effect of lactoferrin addition.

PURPOSE: In this work, the absorption and/or bioavailability of iron from two chemical species, 57Fe-Lf (apo-lactoferrin) complex and 57FeSO4 at low and high dose, and in Lf excess were investigated in lactating wistar rats. METHODS: The methodology used is based on the use of stable isotopes in combination with the approach "isotope pattern deconvolution" and ICP-MS for detection. This approach provides quantitative information about exogenous (57Fe) and endogenous iron (natFe) distribution in fluids and tissues in the iron-supplemented rat groups. RESULTS: The observed results with supplemented rats were compared with those found in rats receiving maternal feeding. Interestingly, differences were found between groups in iron for transport and storage compartments, but not in the functional one, depending upon the dose of iron administered and the chemical species. CONCLUSION: Considering the results obtained, supplementation with iron salts in excess of Lf appears to be the best way of iron supplementation of formula milk.