Organ Histopathological Changes and its Function Damage in Mice Following Long-term Exposure to Lanthanides Chloride

Due to increasing applications of lanthanides (Ln) in industry and daily life, numerous studies confirmed that Ln exposure may result in organ damages in mice and rats, while very few studies focused on several organs damages simultaneously. In order to compare the toxicity of Ln on organs, mice were exposed to LaCl(3), CeCl(3), and NdCl(3) of a dose of 20 mg/kg body weight for consecutive 60 days, respectively, then histopathological changes of liver, kidney, and heart, and their function were investigated. The results showed that long-term exposure to Ln caused cell necrosis and basophilia of liver, ambiguity of renal tubule architecture, congestion of blood vessel and capillary of kidney, and heart hemorrhage. The histopathological changes of liver, kidney, and heart in mice caused by Ce(3+) was most severe; the effect by Nd(3+) was slighter than Ce(3+) but more severe than La(3+). The assay of serum biochemical parameters suggested that Ln exposure severely impaired the functions of liver, kidney, and myocardium in mice. These findings suggested that long-term exposure to Ln resulted in histopathological changes of liver, kidney, and heart, and their function damages. Therefore, we thought that long-term application of the products containing Ln on human should be cautious.     

The cytotoxicity and anticancer mechanisms of alterporriol L, a marine bianthraquinone, against MCF-7 human breast cancer cells

Alterporriol L, a new bianthraquinone derivative, was isolated from a marine fungus Alternaria sp. ZJ9-6B. The cytotoxic activity and anticancer mechanisms of alterporriol L towards breast cancer cells lines were detected using MTT assay, immunofluorescence, and flow cytometry. Simultaneously, the changes in morphological properties of cells were detected before and after treatment with alterporriol L by atomic force microscope (AFM) at a nanometer scale. MTT assay showed that alterporriol L could effectively inhibit the growth and proliferation, and there was a dose-dependent manner of cell death. Moreover, the alterporriol L could induce cancer cell apoptosis or necrosis. Furthermore, the reactive oxygen species, mitochondrial membrane potential, and cytosolic free calcium level were changed after treatment with alterporriol L, suggesting that alterporriol L played vital roles in breast cancer cells through destroying the mitochondrial. And all these alterations are in accord with changes of morphology detected by AFM, which suggested that the AFM is a useful tool to detect the morphological changes of the cancer cells.     

Phosphatidylinositol-3-kinase C2β and TRIM27 function to positively and negatively regulate IgE receptor activation of mast cells

Cross-linking of the IgE receptor (FcεRI) on mast cells plays a critical role in IgE-dependent allergy, including allergic rhinitis, asthma, anaphylaxis, and immediate-type hypersensitivity reactions. Previous studies have demonstrated that the K(+) channel, KCa3.1, plays a critical role in IgE-stimulated Ca(2+) entry and degranulation in both human and mouse mast cells. We now have shown that the class II phosphatidylinositol-3-kinase C2β (PI3KC2β) is necessary for FcεRI-stimulated activation of KCa3.1, Ca(2+) influx, cytokine production, and degranulation of bone marrow-derived mast cells (BMMC). In addition, we found that the E3 ubiquitin ligase, tripartite motif containing protein 27 (TRIM27), negatively regulates FcεRI activation of KCa3.1 and downstream signaling by ubiquitinating and inhibiting PI3KC2β. TRIM27(-/-) mice are also more susceptible in vivo to acute anaphylaxis. These findings identify TRIM27 as an important negative regulator of mast cells in vivo and suggest that PI3KC2β is a potential new pharmacologic target to treat IgE-mediated disease.     

Activation of ERK1/2 and PI3K/Akt by IGF-1 on GAP-43 Expression in DRG Neurons with Excitotoxicity Induced by Glutamate In Vitro

Insulin-like growth factor-1 (IGF-1) is a neurotrophic factor and plays an important role in promoting axonal growth from dorsal root ganglion (DRG) neurons. Whether IGF-1 influences growth-associated protein 43 (GAP-43) expression and activates the extracellular signal-regulated protein kinase (ERK1/2) and the phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathways in DRG neurons with excitotoxicity induced by glutamate (Glu) remains unknown. In this study, embryonic 15-day-old rat DRG explants were cultured for 48 h and then exposed to IGF-1, Glu, Glu + IGF-1, Glu + IGF-1 + PD98059, Glu + IGF-1 + LY294002, Glu + IGF-1 + PD98059 + LY294002 for additional 12 h. The DRG explants were continuously exposed to growth media as control. The levels of GAP-43 mRNA were detected by real time-PCR analysis. The protein levels of GAP-43, phosphorylated ERK1/2, phosphorylated Akt, total ERK1/2, and total Akt were detected by Western blot assay. GAP-43 expression in situ was determined by immunofluorescent labeling. Apoptotic cell death was monitored by Hoechst 33342 staining. IGF-1 alone increased GAP-43 and its mRNA levels in the absence of Glu. The decreased GAP-43 and its mRNA levels caused by Glu could be partially reversed by the presence of IGF-1. IGF-1 rescued neuronal cell death caused by Glu. Neither the ERK1/2 inhibitor PD98059 nor the PI3K inhibitor LY294002 blocked the effect of IGF-1, but both inhibitors together were effective. To validate the impact of GAP-43 expression by IGF-1, GAP-43 induction was blocked by administration of dexamethasone (DEX). IGF-1 partially rescued the decrease of GAP-43 and its mRNA levels induced by DEX. DEX induced an increase of cell apoptosis. IGF-1 may play an important role in neuroprotective effects on DRG neurons through regulating GAP-43 expression with excitotoxicity induced by Glu and the process was involved in both ERK1/2 and PI3K/Akt signaling pathways.     

METCAM/MUC18 augments migration, invasion, and tumorigenicity of human breast cancer SK-BR-3 cells

Previous research has identified METCAM/MUC18, an integral membrane cell adhesion molecule (CAM) in the Ig-like gene super-family, as a promoter or a suppressor in the development of human breast cancer by MCF7, MDA-MB-231, and MDA-MB-468. To resolve these conflicting results we have investigated the role of this CAM in the progression of the three aforementioned cell lines plus one additional human breast cancer cell line, SK-BR-3. We transfected the SK-BR-3 cells with human METCAM/MUC18 cDNA to obtain G418-resistant clones, which expressed different levels of the protein and which were used to test the effect of human METCAM/MUC18 expression on in vitro motility, invasiveness, anchorage-independent colony formation in soft agar, disorganized growth in a 3D basement membrane culture assay, and in vivo tumorigenesis in athymic nude mice. Enforced METCAM/MUC18 expression increased in vitro motility, invasiveness, and anchorage-independent colony formation of SK-BR-3 cells and favored disorganized growth of the cells in 3D basement membrane culture. Enforced expression also increased tumorigenicity and final tumor weights of SK-BR-3 clones/cells after subcutaneous injection of the cells under the left third nipple of female athymic nude mice. To understand the mechanisms, we also determined the expression of several downstream key effectors in the tumors. Tumor cells from METCAM/MUC18 expressing clones exhibited elevated expression of an anti-apoptotic and survival index (Bcl2), an aerobic glycolysis index (LDH-A), and pro-angiogenesis indexes (VEGF and VAGFR2). We concluded that human METCAM/MUC18 promotes the development of breast cancer cells by increasing an anti-apoptosis and survival pathway and augmenting aerobic glycolysis and angiogenesis.     

Single-cell exome sequencing reveals single-nucleotide mutation characteristics of a kidney tumor

Clear cell renal cell carcinoma (ccRCC) is the most common kidney cancer and has very few mutations that are shared between different patients. To better understand the intratumoral genetics underlying mutations of ccRCC, we carried out single-cell exome sequencing on a ccRCC tumor and its adjacent kidney tissue. Our data indicate that this tumor was unlikely to have resulted from mutations in VHL and PBRM1. Quantitative population genetic analysis indicates that the tumor did not contain any significant clonal subpopulations and also showed that mutations that had different allele frequencies within the population also had different mutation spectrums. Analyses of these data allowed us to delineate a detailed intratumoral genetic landscape at a single-cell level. Our pilot study demonstrates that ccRCC may be more genetically complex than previously thought and provides information that can lead to new ways to investigate individual tumors, with the aim of developing more effective cellular targeted therapies.     

Alteration of nutrient allocation and transporter genes expression in rice under N,P, K,and Mg deficiencies

Nitrogen (N), phosphorus (P), potassium (K), and magnesium (Mg) have essential physiological functions in plants. Their interactions in plants are not fully understood especially at the molecular level. In this study, we detected the physiological and molecular responses of rice plants at the vegetative growth phase to N, P, K, and Mg starvations. Deficiencies of N and P resulted in accumulation of soluble sugar and starch in the leaves. The root to shoot ratio increased under N and P deficiencies, but decreased under K and Mg deficiencies. In addition, deficiency of either K or Mg resulted in accumulation of the other cation in shoots. Moreover, K starvation decreased both K and soluble sugar contents in the roots pronouncedly. RT-PCR analysis showed that several sugar transporter genes in the leaves orchestrated with sugar accumulation induced by the nutrient shortages. Expression of a high affinity K transporter gene (OsHAK1) and a putative Mg transporter gene (OsMGT) showed opposite down- and up-regulation in the roots by K starvation. These findings suggest that deficiencies of the major nutrients suppressed the export of carbohydrates from source leaves. The regulated sugar and nutrient transporter genes investigated in this study could be used for elucidating the molecular mechanism of plants in their adaptation to varied nutrient supply.     

Paclobutrazol and plant-growth promoting bacterial endophyte Pantoea sp. enhance copper tolerance of guinea grass (Panicum maximum) in hydroponic culture

As most gramineous plants, guinea grass (Panicum maximum) comprise cellulosic biomass, which may be used as a feedstock for bioenergy. In order to develop such potential energy plants on copper-polluted lands, the hydroponic experiments with Cu, Paclobutrazol (PP333, a kind of antigibberellin) and plant growth-promoting bacterial endophyte (PGPB) treatments were carried out in a greenhouse. The seedlings of two cultivars of guinea grass, GG1 (P. maximum var. Natsukomaki) and GG2 (P. maximum var. Natsukaze) in 3 weeks old were treated, respectively, with different Cu treatments [0(CK), 100, 200, 300, 400, 500 μM l⁻¹ Cu] for estimating Cu toxicity. The results showed that elevated Cu restrained plant growth and reduced biomass. According to the EC50 value [the Cu concentration when the relative gain in fresh weight ratio was 50% of control] of two tested cultivars, the concentration of Cu for further experiments was decided as 300 μM l⁻¹. Both pretreatments of PP333 (200, 400, 600 mg l⁻¹) and PGPB (Pantoea sp.) significantly alleviated the negative affect caused by stress of 300 μM l⁻¹ Cu. The pretreatment of 400 mg l⁻¹ PP333 promoted both two cultivars in biomass, compared to 300 μM l⁻¹ Cu treat. The inoculation of Pantoea sp. Jp3-3 increased shoot dry weight, compared to Cu treat. The results suggested that the main reason for both PP333 and Pantoea sp. Jp3-3 enhanced Cu tolerance in guinea grass was that their pretreatments significantly decreased Cu absorption and accumulation under excessive Cu stress. The present study has provided a new insight into the exploitation of energy plant in heavy metal polluted condition by the way of plant growth regulation for increasing heavy metal tolerance.