The toxicity of cooking oil fumes on human bronchial epithelial cells through ROS-mediated MAPK, NF-κB signaling pathways and NLRP3 inflammasome.

Cooking oil fumes (COFs) are the main pollutants in kitchen and indoor air, which threaten human health. Exposure to COFs may lead to respiratory diseases and impair pulmonary function. To investigate the toxicity of COFs on human bronchial epithelial cells (Beas-2B) and explore the underlying mechanisms, MTT assay was conducted to detect the viability of Beas-2B. Intracellular reactive oxygen species (ROS) levels and nitric oxide (NO) levels were determined with DCFH-DA assay and DAF-FM assay. The expression of genes involved in inflammation were measured with quantitative real-time PCR (qRT-PCR). The phosphorylation and the expression of proteins related to Mitogen-activated protein kinase (MAPK), NF-κB signaling pathways were measured with western blot. Our results revealed that COFs decreased cell viability, increased the ROS levels and NO levels and induced apoptosis in Beas-2B cells. The results of qRT-PCR and western blot showed that the expression of NLRP3, p65, iNOS, IL-1ß, and the factors related to oxidative stress and inflammation increased, NF-κB signaling pathway and MAPK signaling pathway were activated. This study provided some useful information to evaluate the toxicity of COFs and revealed the possible mechanism for the damage on respiratory system induced by COFs.

Bovine lactoferrin and Lentinus edodes mycelia polysaccharide complex: The formation and the activity to protect islet ß cells.

The formation of complexes may be used for the development of delivery systems in foods field. The aim of this study was to explore the interaction mechanism between Lentinus edodes mycelia polysaccharide (LMP) and bovine lactoferrin (BLF), and the activity of LMP-BLF complex to inhibit oxidative stress in islet ß cells. The interaction mechanisms of LMP with BLF were investigated with multi-spectroscopic techniques. The multi-spectroscopic analysis result showed that LMP bound with BLF by van der Waals force and hydrogen bond. The quenching mechanism of BLF with LMP was static quenching. Cell viability, reactive oxygen species (ROS) level, apoptosis and the related signaling pathways were detected with thiazolyl blue tetrazolium bromide (MTT) assay, 2,7-Dichlorofluorescin diacetate (DCFH-DA) staining, Hoechst 33258 staining and Western blot methods respectively. The complex alleviated apoptosis induced by hydrogen peroxide (H2O2), and inhibited oxidative stress via MAPK pathways in MIN6 cells. In addition, the complex was able to promote glucose uptake in HepG2 cells. These results will broaden our understanding of LMP-BLF complexes and the applications of polysaccharide-protein complexes in the foods field.

Cadmium induced BEAS-2B cells apoptosis and mitochondria damage via MAPK signaling pathway.

Cadmium, a heavy metal pollutant in industrial production, is found in air, water and soil, which is harmful to human health and can lead to diseases, such as asthma, lung cancer, and emphysema. In this study, the toxicity of cadmium on human bronchial epithelial cells (BEAS-2B) was investigated. Cell viability, mitochondrial membrane potential, reactive oxygen species (ROS) level, apoptosis and the related signaling pathways were detected with MTT assay, Rhodamine staining, DCFH-DA staining, Hoechst33258 staining and Western blot methods respectively. The results showed that the cell viability decreased, the mitochondrial membrane potential declined, ROS was accumulated and apoptotic rate raised in BEAS-2B cells. Meanwhile, the expression of B-cell lymphoma-2 (Bcl-2) was downregulated, while the expression of Bcl-2-associated X protein (Bax) and the cleaved caspase-3 was upregulated, which indicated mitochondria-mediated intrinsic apoptosis pathway was activated. Furthermore, the phosphorylation of JNK, ERK and p38 was enhanced respectively, which manifested that MAPK signaling pathways were activated. Therefore, it could be concluded that cadmium could increase intracellular ROS, result in cellular oxidative stress, activate JNK, ERK and p38 MAPK pathways and ultimately lead to apoptosis of BEAS-2B cells by activating mitochondria-mediated intrinsic apoptosis pathway. This study provided useful information to elucidate the toxicity of cadmium and revealed the possible mechanism for the occurrence of lung disease induced by cadmium.

A study on the protective effects of taxifolin on human umbilical vein endothelial cells and THP-1 cells damaged by hexavalent chromium: a probable mechanism for preventing cardiovascular disease induced by heavy metals.

Hexavalent chromium [Cr(vi)] which is a kind of heavy metal with strong oxidizing ability can induce cardiovascular disease (CVD), while taxifolin can protect cells and organisms against suffering from oxidative stress. In this study, the inhibitory effects of taxifolin against Cr(vi)-induced cell damage in human umbilical vein endothelial cells (HUVECs) and THP-1 cells were investigated. Cr(vi) could increase the phosphorylation of p38 and JNK, regulate the expression of Bax and Bcl-2 in both cell lines. Meanwhile, the Cr(vi) stimulation led to an increase of the expression of ICAM-1 and VCAM-1, and upregulated the adhesion of THP-1 cells to HUVECs. Furthermore, Cr(vi) could induce the activation of the nuclear factor kappa B (NF-κB) signaling pathway, the accumulation of p65 in the nucleus, and the increase in the phosphorylation of IκB and the expression of cleaved caspase-1 and IL-1ß in THP-1 cells. However, taxifolin could reverse the effects by inhibiting the activation of mitogen-activated protein kinases (MAPKs) and NF-κB signaling pathways, regulating the expression of apoptosis-related proteins, and alleviating the adhesion of THP-1 cells to HUVECs. Our findings demonstrated that taxifolin was a potential agent to prevent endothelial dysfunction, monocyte inflammation and cell adhesion induced by Cr(vi).

The protective effects of a novel polysaccharide from Lentinus edodes mycelia on islet ß (INS-1) cells damaged by glucose and its transportation mechanism with human serum albumin.

High glucose can lead to toxicity on islet ß cells. The protective effects of a novel Lentinus edodes mycelia polysaccharide (LMP) on INS-1 cells damaged by glucose were investigated. Cell viability, lactate dehydrogenase (LDH) release, cell apoptosis, intracellular reactive oxygen species (ROS), superoxide dismutase (SOD) activity, and malondialdehyde (MDA) content were detected. P38 MAPK, JNKand NF-κB pathways were analyzed to reveal the inhibitory mechanism of LMP on glucose-induced INS-1 cells toxicity. The results showed that LMP could decrease cellular oxidative stress, reduce intracellular ROS levels, decrease MDA content and increase SOD activity. Furthermore, the glucose-induced cell apoptosis in cells were inhibited by regulating the expression of Bax, Bcl-2, cleaved caspase­3 and cleaved caspase­1. Cell signaling pathway analysis revealed that LMP could inhibit the activation of p38 MAPK, JNK, NF-κB pathways and activate Nrf2 pathway. To further explore the possible transportation mechanism of LMP with human serum albumin (HSA), ultraviolet-visible absorption spectroscopy and fluorescence spectroscopy were used to evaluate the interaction between LMP and HSA. The results showed that LMP-HSA complex was formed, which would be helpful for explaining the transportation mechanism in vivo. These results suggested that LMP might be a new therapeutic candidate to alleviate the high glucose toxicity.

Toxic effects of Cr(VI) on the bovine hemoglobin and human vascular endothelial cells: Molecular interaction and cell damage.

Hexavalent chromium [Cr(VI)] is the main harmful component in the atmosphere released by chemical industry. The study was conducted to assess Cr(VI) inducing cardiovascular diseases (CVDs) in vitro by investigating the effects of Cr(VI) on bovine hemoglobin (BHb) and human umbilical vein endothelial cells (HUVECs). Multi-spectroscopic techniques and molecular docking method were used to determine the interaction of Cr(VI) and BHb. Fluorescence spectra results showed that the quenching constant (Ksv) decreased with temperature raise, indicating that Cr(VI) quenches BHb fluorescence through static quenching mechanism. The number of binding sites was 1.14 (310 K), enthalpy and entropy changes revealed the interaction of Cr(VI) and BHb was driven by hydrogen bonds. The results of synchronous fluorescence and circular dichroism (CD) spectra suggested that Cr(VI) could change BHb conformation and influence the microenvironment of Trp and Tyr residues. Moreover, in order to study Cr(VI) induced HUVECs damage, inflammatory factors were detected at the mRNA level, JNK and p38 MAPK pathways were analyzed. The results shown that Cr(VI) could induce mRNA expression of NLRP3, ICAM-1, VCAM-1, TNF-α and IL-1ß, and increased intracellular ROS. Furthermore, Cr(VI) could induce oxidative stress in HUVECs, and then activate JNK and p38 MAPK pathways, ultimately lead to apoptosis of HUVECs by activating mitochondrial apoptosis pathways. These results suggested that Cr(VI) might bring about CVDs by both changing the BHb conformation and inducing HUVECs damage.