Cadmium induces matrix metalloproteinase-9 expression via ROS-dependent EGFR, NF-кB, and AP-1 pathways in human endothelial cells

Mechanisms of Heavy Metal Cadmium (Cd)-Induced Malignancy

The environmental pollution of cadmium is worsening, and its significant carcinogenic effects on humans have been confirmed. Cadmium can induce cancer through various signaling pathways, including the ERK/JNK/p38MAPK, PI3K/AKT/mTOR, NF-κB, and Wnt. It can also cause cancer by directly damaging DNA and inhibiting DNA repair systems, or through epigenetic mechanisms such as abnormal DNA methylation, LncRNA, and microRNA. However, the detailed mechanisms of Cd-induced cancer are still not fully understood and require further investigation.

Aloe vera gel relieves cadmium triggered hepatic injury via antioxidative, anti-inflammatory, and anti-apoptotic routes

Aloe vera (AV) gel extracted from fresh AV leaves was chosen in this study to evaluate its antioxidant, anti-inflammatory, and antiapoptotic activities against cadmium (Cd) -induced liver injury. Forty Wistar male adult rats were equally divided into four groups. Group I (standard control) ingested with 2.5 ml/kg b.w. of physiological saline. Group II (Cd-intoxicated) received 3 mg/kg b.w./day of CdCl2 dissolved in saline. Group III (AV) received 200 mg/kg b.w./day of AV gel dissolved in saline. Group IV (Cd+AV) ingested with 200 mg/kg b.w./day of AV gel solution along with 3 mg/kg b.w. CdCl2. All groups were ingested orally by gavage for 3 consecutive weeks. Paraoxonase-1 (PON-1) and HSP70 were measured in serum. The deposited Cd level, nitric oxide content, lipid peroxidation, collagen-1 (COL-1), and metalloproteinase-9 (MMP-9) levels were all determined in liver tissue homogenates. Gene expression of NF-κB and IL-6, Bax, and Bcl2, as well as immunohistochemistry analysis of activated caspase-3, was performed. Results showed that ingestion of AV gel greatly relieved all oxidative stress due to Cd exposure, modulated the NF-κB, IL-6, Bax, and Bcl2 expression levels, and improved the apoptotic state. In conclusion, AV gel confirmed its potential ameliorating effect against liver injury induced due to Cd exposure.

Contribution of platelets to disruption of the blood-brain barrier during arterial baroreflex dysfunction

BACKGROUND

Arterial baroreflex dysfunction, like many other central nervous system disorders, involves disruption of the blood-brain barrier, but what causes such disruption in ABR dysfunction is unclear. Here we explored the potential role of platelets in this disruption.

METHODS

ABR dysfunction was induced in rats using sinoaortic denervation, and the effects on integrity of the blood-brain barrier were explored based on leakage of Evans blue or FITC-dextran, while the effects on expression of CD40L in platelets and of key proteins in microvascular endothelial cells were explored using immunohistochemistry, western blotting and enzyme-linked immunosorbent assay. Similar experiments were carried out in rat brain microvascular endothelial cell line, which we exposed to platelets taken from rats with ABR dysfunction.

RESULTS

Sinoaortic denervation permeabilized the blood-brain barrier and downregulated zonula occludens-1 and occludin in rat brain, while upregulating expression of CD40L on the surface of platelets and stimulating platelet aggregation. Similar effects of permeabilization and downregulation were observed in healthy rats that received platelets from animals with ABR dysfunction, and in rat brain microvascular endothelial cells, but only in the presence of lipopolysaccharide. These effects were associated with activation of NF-κB signaling and upregulation of matrix metalloprotease-9. These effects of platelets from animals with ABR dysfunction were partially blocked by neutralizing antibody against CD40L or the platelet inhibitor clopidogrel.

CONCLUSION

During ABR dysfunction, platelets may disrupt the blood-brain barrier when CD40L on their surface activates NF-kB signaling within cerebral microvascular endothelial cells, leading to upregulation of matrix metalloprotease-9. Our findings imply that targeting CD40L may be effective against cerebral diseases involving ABR dysfunction.

Mechanisms of Phytoremediation by Resveratrol against Cadmium Toxicity

Cadmium (Cd) toxicity poses a significant threat to human health and the environment due to its widespread occurrence and persistence. In recent years, considerable attention has been directed towards exploring natural compounds with potential protective effects against Cd-induced toxicity. Among these compounds, resveratrol (RV) has emerged as a promising candidate, demonstrating a range of beneficial effects attributed to its antioxidant and anti-inflammatory properties. This literature review systematically evaluates the protective role of RV against Cd toxicity, considering the various mechanisms of action involved. A comprehensive analysis of both in vitro and in vivo studies is conducted to provide a comprehensive understanding of RV efficacy in mitigating Cd-induced damage. Additionally, this review highlights the importance of phytoremediation strategies in addressing Cd contamination, emphasizing the potential of RV in enhancing the efficiency of such remediation techniques. Through the integration of diverse research findings, this review underscores the therapeutic potential of RV in combating Cd toxicity and underscores the need for further investigation to elucidate its precise mechanisms of action and optimize its application in environmental and clinical settings.

Low-dose cadmium induces lymphangiogenesis through activation of the STAT3 signaling pathway

Cadmium (Cd) is a widespread environmental toxicant that poses significant threat to public health. After intake, Cd is distributed throughout the body via blood and lymphatic circulation. However, the effect of Cd on lymphatic vessels has not been revealed. In this study, mice were exposed to 10 μM cadmium chloride through drinking water immediately after corneal alkali burn. In vivo analyses showed that Cd treatment enhances the alkali burn-induced corneal lymphangiogenesis, which is characterized by increased expression of lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1), prospero-related homeobox 1 (PROX-1) and vascular endothelial growth factor receptor 3 (VEGFR3). In vitro, the proliferation and migration of human dermal lymphatic endothelial cells (HDLECs) are increased by 1 μM Cd treatment, while inhibited by 10 μM Cd treatment. At a concentration of 1 μM, Cd specifically induces phosphorylation of signal transducer and activator of transcription 3 (STAT3), but has no effect on the MAPK, AKT, or NF-κB signaling pathway. In the presence of the STAT3 inhibitor STATTIC, Cd fails to induce HDLECs proliferation and migration. In addition, Cd upregulates VEGFR3 expression and its gene promoter activity in a STAT3-dependent manner. Our study suggests that low-dose Cd promotes lymphangiogenesis through activation of the STAT3 signaling pathway.

Recent Updates on the Therapeutics Benefits, Clinical Trials, and Novel Delivery Systems of Chlorogenic Acid for the Management of Diseases with a Special Emphasis on Ulcerative Colitis

Ulcerative colitis (UC) is a multifactorial disorder of the large intestine, especially the colon, and has become a challenge globally. Allopathic medicines are primarily available for the treatment and prevention of UC. However, their uses are limited due to several side effects. Hence, an alternative therapy is of utmost importance in this regard. Herbal medicines are considered safe and effective for managing human health problems. Chlorogenic acid (CGA), the herbal-derived bioactive, has been reported for pharmacological effects like antiinflammatory, immunomodulatory, antimicrobial, hepatoprotective, antioxidant, anticancer, etc. This review aims to understand the antiinflammatory and chemopreventive potential of CGA against UC. Apart from its excellent therapeutic potential, it has been associated with low absorption and poor oral bioavailability. In this context, colon-specific novel drug delivery systems (NDDS)are pioneering to overcome these problems. The pertinent literature was compiled from a thorough search on various databases such as ScienceDirect, PubMed, Google Scholar, etc., utilizing numerous keywords, including ulcerative colitis, herbal drugs, CGA, pharmacological activities, mechanism of actions, nanoformulations, clinical updates, and many others. Relevant publications accessed till now were chosen, whereas non-relevant papers, unpublished data, and non-original articles were excluded. The present review comprises recent studies on pharmacological activities and novel drug delivery systems of CGA for managing UC. In addition, the clinical trials of CGA against UC have been discussed.

Reactive Oxygen Species: A Crosslink between Plant and Human Eukaryotic Cell Systems

Reactive oxygen species (ROS) are important regulating factors that play a dual role in plant and human cells. As the first messenger response in organisms, ROS coordinate signals in growth, development, and metabolic activity pathways. They also can act as an alarm mechanism, triggering cellular responses to harmful stimuli. However, excess ROS cause oxidative stress-related damage and oxidize organic substances, leading to cellular malfunctions. This review summarizes the current research status and mechanisms of ROS in plant and human eukaryotic cells, highlighting the differences and similarities between the two and elucidating their interactions with other reactive substances and ROS. Based on the similar regulatory and metabolic ROS pathways in the two kingdoms, this review proposes future developments that can provide opportunities to develop novel strategies for treating human diseases or creating greater agricultural value.

Metastatic effects of environmental carcinogens mediated by MAPK and UPR pathways with an in vivo Drosophila Model

Metastasis includes tumor invasion and migration and underlies over 90% of cancer mortality. The metastatic effects of environmental carcinogens raised serious health concerns. However, the underlying mechanisms remained poorly studied. In the present study, an in vivo Ras^V12/lgl^-/- model of the fruitfly, Drosophila melanogaster, with an 8-day exposure was employed to explore the metastatic effects of 3,3',4,4',5-pentachlorobiphenyl (PCB126), perfluorooctanoic acid (PFOA) and cadmium chloride (CdCl₂). At 1.0 mg/L, PCB126, PFOA, and CdCl₂ significantly increased tumor invasion rates by 1.32-, 1.33-, and 1.29-fold of the control, respectively. They also decreased the larval body weight and locomotion behavior. Moreover, they commonly disturbed the expression levels of target genes in MAPK and UPR pathways, and their metastatic effects were significantly abolished by the addition of p38 inhibitor (SB203580), JNK inhibitor (SP600125) and IRE1 inhibitor (KIRA6). Notably, the addition of the IRE inhibitor significantly influenced sna/E-cad pathway which is essential in both p38 and JNK regulations. The results demonstrated an essential role of sna/E-cad in connecting the effects of carcinogens on UPR and MAPK regulations and the resultant metastasis.

Molecular Background of Toxic-Substances-Induced Morphological Alterations in the Umbilical Cord Vessels and Fetal Red Blood Cells

The relationship between smoking and human health has been investigated mostly in adults, despite the fact that the chemicals originating from sustained maternal smoking disrupt the carefully orchestrated regulatory cascades in the developing fetus. In this study, we followed molecular alterations in the umbilical cord (UC) vessels and fetal red blood cells (RBCs), which faithfully reflect the in vivo status of the fetus. We showed evidence for the decreased level of DNA-PKcs-positive nuclei in samples with smoking origin, which is associated with the impaired DNA repair system. Furthermore, we pointed out the altered ratio of MMP-9 metalloproteinase and its endogenous inhibitor TIMP-1, which might be a possible explanation for the morphological abnormalities in the UC vessels. The presented in vivo dataset emphasizes the higher vulnerability of the veins, as the primary target for the toxic materials unfiltered by the placenta. All these events become amplified by the functionally impaired fetal RBC population via a crosstalk mechanism between the vessel endothelium and the circulating RBCs. In our ex vivo approach, we looked for the molecular explanation of metal-exposure-induced alterations, where expressions of the selected genes were upregulated in the control group, while samples with smoking origin showed a lack of response, indicative of prior long-term in utero exposure.

Chronic Cadmium Exposure and Genetic Polymorphisms of MMP-2 and MMP-9 in a Population Exposed to Steel Slag in the State of Rio de Janeiro, Brazil: A Cross-Sectional Study

Genetic polymorphisms in the matrix metalloproteinases (MMPs) family genes may be associated with cadmium (Cd) levels and its adverse effects. This study investigated the impact of MMP-2 and MMP-9 polymorphisms on Cd levels in 238 residents of a condominium in Rio de Janeiro, Brazil, built over an industrial steel slag waste. Polymorphisms were genotyped using TaqMan validated assays, and the Cd levels were measured in blood (BCd) and urine (UCd) samples by atomic absorption spectrometry. Associations were evaluated by linear correlation coefficients and multiple logistic regression, using odds ratios (OR) and 95% confidence intervals (CI). Mean age was 50 ± 15 years; 58% were female, 69% non-smokers. Mean concentrations for BCd and UCd were 0.70 ± 0.2 μg L^-1 and 0.56 ± 0.55 μg L^-1, respectively. Smoking status was associated with BCd ≥ 0.70 μg L^-1 (OR = 2.9; 95% CI = 1.6-5.9). MMP-9 rs17576 A > G was associated with BCd ≥ 0.70 μg L^-1 (OR = 2.11; 95% CI = 1.10-4.05) and UCd ≥ 0.56 μg L^-1 (OR = 3.38; 95% CI = 1.82-7.65). Knowing possible individual predisposing factors is essential to understand Cd toxicity, and to improve the monitoring of high-risk populations.

Sulforaphane Suppresses the Nicotine-Induced Expression of the Matrix Metalloproteinase-9 via Inhibiting ROS-Mediated AP-1 and NF-κB Signaling in Human Gastric Cancer Cells

Sulforaphane, a natural phytochemical compound found in various cruciferous vegetables, has been discovered to present anti-cancer properties. Matrix metalloproteinase-9 (MMP-9) plays a crucial role in gastric cancer metastasis. However, the role of sulforaphane in MMP-9 expression in gastric cancer is not yet defined. Nicotine, a psychoactive alkaloid found in tobacco, is associated with the development of gastric cancer. Here, we found that sulforaphane suppresses the nicotine-mediated induction of MMP-9 in human gastric cancer cells. We discovered that reactive oxygen species (ROS) and MAPKs (p38 MAPK, Erk1/2) are involved in nicotine-induced MMP-9 expression. AP-1 and NF-κB are the critical transcription factors in MMP-9 expression. ROS/MAPK (p38 MAPK, Erk1/2) and ROS functioned as upstream signaling of AP-1 and NF-κB, respectively. Sulforaphane suppresses the nicotine-induced MMP-9 by inhibiting ROS-mediated MAPK (p38 MAPK, Erk1/2)/AP-1 and ROS-mediated NF-κB signaling axes, which in turn inhibit cell invasion in human gastric cancer AGS cells. Therefore, the current study provides valuable evidence for developing sulforaphane as a new anti-invasion strategy for human gastric cancer therapy.

Cadmium induces the expression of Interleukin-6 through Heme Oxygenase-1 in HK-2 cells and Sprague-Dawley rats

Cadmium is toxic to the kidney through mechanisms involving oxidative stress and inflammation. We studied reciprocal crosstalk among the oxidative stress, inflammation, and the nuclear Nrf2 pathway in cadmium-induced nephrotoxicity on HK-2 human renal proximal tubular epithelial cells. Cadmium chloride (CdCl2) caused cell viability loss, Reactive Oxygen Species (ROS) generation, glutathione reduction, and Interleukin-6 (IL-6) expression, accompanied by Nrf2 activation and Heme Oxygenase-1 (HO-1) expression. Pharmacological treatments demonstrated cytotprotective and anti-inflammatory effects of Nrf2 activation. Intriguingly, inhibition of HO-1 activity mitigated cell viability loss and IL-6 expression in CdCl2-treated cells. Parallel attenuation by HO-1 inhibitor was demonstrated in cadmium-induced ROS generation and glutathione reduction. CdCl2-treated cells also increased levels of ferrous iron, cGMP, Mitogen-Activated Protein Kinases phosphorylation, as well as NF-κB DNA-binding activity. These increments were mitigated by antioxidant N-Acetyl Cysteine, HO-1 inhibitor SnPP, and PKG inhibitor KT5823, and were mimicked by the Carbon Monoxide-releasing compound. In the kidney cortex of CdCl2-exposed Sprague-Dawley rats, we found similar renal injury, histological changes, ROS generation, IL-6 expression, and accompanied pro-oxidant and pro-inflammatory changes. These observations indicated that cadmium-induced nephrotoxicity was associated with oxidative stress and inflammation, and HO-1 likely acts as a linking molecule to induce nephrotoxicity-associated IL-6 expression upon cadmium exposure.

Nicotine stimulates IL-8 expression via ROS/NF-κB and ROS/MAPK/AP-1 axis in human gastric cancer cells

Nicotine, a major alkaloid found in tobacco, is a significant risk factor for gastric cancer. IL-8, a pleiotropic cytokine, plays a vital role in cancer cell metastasis. The role of nicotine in IL-8 expression and the underlying mechanism is currently unknown. Here, we examined the effects of nicotine on IL-8 expression and explored the potential mechanisms in gastric cancer cells. We found that nicotine increases IL-8 expression. Specific inhibitor and mutagenesis studies showed that ROS and MAPK (Erk1/2, p38) were involved in this process. Deletion and site-directed mutagenesis studies indicate the involvement of transcription factor NF-κB and AP-1. ROS and ROS/MAPK (Erk1/2, p38) functioned as the upstream signaling molecules in the activation of NF-κB and AP-1, respectively. AGS gastric cancer cells pretreated with nicotine stimulate angiogenesis in the tumor microenvironment, partially abrogated by silencing IL-8 in AGS cells. In this study, we found that nicotine induces IL-8 expression via ROS/NF-κB and ROS/MAPK (Erk1/2, p38)/AP-1 axis in gastric cancer cells, thus stimulating endothelial cell proliferation and angiogenesis in the tumor microenvironment.

Local and Systemic Expression Pattern of MMP-2 and MMP-9 in Complex Regional Pain Syndrome

Matrix metalloproteinases (MMP)-2 and MMP-9 play important roles in inflammation as well as in pain processes. For this reason, we compared the concentrations of these enzymes in skin and serum of patients with complex regional pain syndrome (CRPS), other pain diseases and healthy subjects. We analyzed ipsi- and contralateral skin biopsies of 18 CRPS patients, as well as in 10 pain controls and 9 healthy subjects. Serum samples were analyzed from 20 CRPS, 17 pain controls and 17 healthy subjects. All samples were analyzed with ELISA. Concentrations were then compared to clinical data as well as to quantitative sensory testing data.MMP-2 was increased in both ipsi- and contralateral skin biopsies of CRPS patients compared to healthy subjects. While low ipsilateral MMP-2 was associated with trophic changes, contralateral MMP-2 inversely correlated with the CRPS severity. MMP-9 was also locally increased in ipsilateral CRPS skin, and higher ipsi- and contralateral MMP-9 levels correlated with CRPS severity. We conclude that MMP-2 and MMP-9 are differently expressed depending on the clinical phenotype in CRPS. PERSPECTIVE: This article describes an upregulation of MMPs in CRPS and pain controls and shows different expression of MMP-2 and -9 depending on clinical phenotype in CRPS. These results provide evidence that MMP-2 and -9 play a key role in CRPS pathophysiology.

Effect of Fractions from Lycopus lucidus Turcz. Leaves on Genomic DNA Oxidation and Matrix Metalloproteinase Activity

AIM AND OBJECTIVE

We investigated the inhibitory effects of fractions from Lycopus lucidus Turcz. leaves on genomic DNA oxidation, nitric oxide (NO) production and matrix metalloproteinase (MMP) activity.

MATERIAL AND METHODS

Oxidative damage of genomic DNA was detected after Fenton reaction with H₂O₂ using DNA electrophoresis. Western blotting was performed to compare the expression levels of MMP-2 in phorbol 12-myristate 13-acetate (PMA)-induced HT-1080 cells. Lipopolysacchride (LPS)-induced NO production in RAW 264.7 cells was measured using Griess reagent.

RESULTS

All fractions (n-Hexane, 85% aq. MeOH, n-BuOH, and water fractions) from the leaves of L. lucidus Turcz. significantly inhibited intracellular production of reactive oxygen species (ROS) (p<0.05). Particularly, 85% aq. MeOH and n-BuOH fractions showed higher ROS inhibitory activity than the other fractions. n-Hexane, 85% aq. MeOH, n-BuOH and water (0.05 mg/mL) fractions significantly inhibited oxidative DNA damage by 57.97%, 68.48%, 58.97%, and 68.39%, respectively (p <0.05). Treatment of RAW 264.7 cells with each fraction reduced LPS-induced NO production in a dose-dependent manner (p<0.05). n-Hexane and 85% aq. MeOH fractions notably reduced MMP-2 secretion levels of in the culture supernatants from HT-1080 cells.

CONCLUSION

Overall, these results indicated that L. lucidus Turcz. leaves can be exploited as plant based sources of antioxidants in the pharmaceutical, cosmetic, nutraceutical and food industries.

Chronic Cadmium Exposure Alters Cardiac Matrix Metalloproteinases in the Heart of Sprague-Dawley Rat

The aim of this study was to evaluate the role of chronic cadmium exposure in modulating cardiac matrix metalloproteinases (MMPs) in the heart of rats. Adult male Sprague-Dawley rats were exposed to 15 ppm CdCl₂ in drinking water for 10 weeks followed by withdrawal of cadmium treatment for 4 weeks. Following the completion of the treatment, gene expression of inflammatory mediators (IL-1β, IL-6, IL-10, TNF-α and NF-κB), protein expression of MMP-2, MMP-9 and their respective inhibitors- TIMP-1 and TIMP-2, and gelatinolytic activity of MMP-2 and MMP-9 were determined. At the protein level, cadmium incites a differential effect on the expression and activity of gelatinases and their endogenous inhibitors in an exposure-dependent manner. Results also show that the administered cadmium dose elicits an inflammatory response until week 10 that slightly diminishes after 4 weeks. This study provides evidence of cadmium-induced imbalance in the MMP-TIMP system in the cardiac tissue. This imbalance may be mediated by cadmium-induced inflammation that could contribute to various cardiovascular pathologies.

Bio-indicators in cadmium toxicity: Role of HSP27 and HSP70

Heat shock proteins (HSPs) are a family of proteins that are expressed by cells in reply to stressors. The changes in concentration of HSPs could be utilized as a bio-indicator of oxidative stress caused by heavy metal. Exposure to the different heavy metals may induce or reduce the expression of different HSPs. The exposure to cadmium ion (Cd²⁺) could increase HSP70 and HSP27 over 2- to 10-fold or even more. The in vitro and in vivo models indicate that the HSP70 family is more sensitive to Cd intoxication than other HSPs. The analyses of other HSPs along with HSP70, especially HSP27, could also be useful to obtain more accurate results. In this regard, this review focuses on examining the literature to bold the futuristic uses of HSPs as bio-indicators in the initial assessment of Cd exposure risks in defined environments.

The role of PKA/PP2B-mediated Drp1 phosphorylation and the subsequent EGFR inhibition in Cr(VI)-induced premature senescence

In recent years, frequent hexavalent chromium [Cr(VI)] pollution incidents have severely damaged the ecology and endangered the public health. It is well known that cell senescence could promote the carcinogenesis, thus the related research on the occurrence of premature senescence is of great significance to the elucidation of the carcinogenic mechanism of Cr(VI). We previously confirmed that long-term low-dose Cr(VI) exposure induced premature senescence, but the key molecular events that determine the occurrence of premature senescence are still unclear. In the present study, we found that Cr(VI) induced phosphorylation of dynamin-relatedprotein 1 (Drp1)-S637 site in premature senescent cells, which was accompanied with the decrease of mitochondrial fission. We also demonstrated that the phosphorylation status of Drp1-S637 after Cr(VI) exposure was related to the antagonism of PKA/PP2B, and continuous dephosphorylation of Drp1-S637 attenuated premature senescence caused by Cr(VI). The epidermal growth factor receptor (EGFR) overexpression significantly alleviated the occurrence of premature senescence, and the expressions of EFGR and its downstream molecules were related to the phosphorylation status of Drp1-S637. In brief, we revealed the role of PKA/PP2B-mediated Drp1 phosphorylation and the subsequent EGFR inhibition in Cr(VI)-induced premature senescence. This study is the first time to link the phosphorylation of Drp1 with Cr(VI)-induced premature senescence, in order to find the key molecular events that determine the occurrence of premature senescence and demonstrate the molecular mechanism of abnormal elongated mitochondria formation in the senescence process. The significance of this study is to explore the carcinogenesis of Cr(VI) and provide new ideas and strategies for the targeted treatment of Cr(VI)-related cancers.

Nephrotoxicity Profile of Cadmium Revealed by Proteomics in Mouse Kidney

Cadmium (Cd) is a highly toxic metal and kidney is its main target. However, the molecular effects and associated potential impacts of Cd-accumulated kidney have not been well investigated. In this study, mouse was used as a model to investigate the Cd-induced proteomic profile change in kidney, and a total of 34 differentially expressed proteins were detected by two-dimensional gel electrophoresis (2-DE) and further identified by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS). Through Gene Ontology analysis and KEGG pathway annotation, it showed that Cd-regulated kidney metabolism and promoted renal damage and cell migration. By validation of Western blotting and RT-qPCR, metastasis-related proteins LIM and SH3 domain protein 1 (LASP1) and phosphoenolpyruvate carboxykinase/cytosolic [GTP] (PEPCK1) were confirmed to be upregulated; Acyl-CoA synthetase medium-chain family member 3 (ACSM3) was downregulated. Furthermore, carcinoma development-related proteins initiation factor 4A (eIF4A) and pyridoxine-5'-phosphate oxidase (PNPO) were upregulated, and pyridoxal kinase (PK) was downregulated. The downregulation of Na(+)/H(+) exchange regulatory cofactor (NHERF3) might promote renal damage which associated with decrease of transferrin (TRF) in kidney. Taken together, our results revealed proteomic profile of Cd-induced nephrotoxicity and provided data for further insights into the mechanisms of Cd toxicity.

Sustained Maternal Smoking Triggers Endothelial-Mediated Oxidative Stress in the Umbilical Cord Vessels, Resulting in Vascular Dysfunction

Nitric oxide (NO) bioavailability is fundamental in the regulation of redox balance and functionality of the endothelium, especially in the case of the umbilical cord (UC), which has no innervation. The analysis of UC vessel-related complications could serve as a useful tool in the understanding of the pathophysiological mechanisms leading to neonatal cardiovascular disorders. Therefore, the aim of this study was to characterize the mechanisms that rule the severity of prenatal endothelial dysfunction, induced by the long-term effect of maternal smoking. Our analysis describes the initiation and the consequences of endothelial nitric oxide synthase (NOS3) deactivation, along with the up-regulation of possible compensatory pathways, using structural, molecular and biochemical approaches. This study was carried out on both the UC arteries and veins originated from neonates born to non-smoking and heavy-smoking mothers. The alterations stimulated by maternal smoking are vessel-specific and proportional to the level of exposure to harmful materials passed through the placenta. Typically, in the primarily exposed veins, an increased formation of reactive oxygen species and an up-regulation of the highly-efficient NOS2-NO producing pathway were detected. Despite all the extensive structural and functional damages, the ex vivo heat and cadmium ion-treated UC vein pieces still support the potential for stress response.

Protective effects and molecular mechanisms of Achyranthes bidentata polypeptide k on Schwann cells

Background

Achyranthes bidentata polypeptide k (ABPPk) is an active ingredient used in traditional Chinese medicine separated from Achyranthes bidentata polypeptides. So far, the role of ABPPk in peripheral nerve protection has not been comprehensively studied.

Methods

In this study, primary Schwann cells exposed to serum deprivation were treated with ABPPk or nerve growth factor (NGF) in vitro. Cell viability, cell apoptosis, apoptosis-related protein expression, and antioxidant enzyme activity were analyzed. To further explore the underlying molecular mechanisms and key regulatory molecules involved in the effects of ABPPk, integrative and dynamic bioinformatics analysis at different time points was carried out following RNA-seq of Schwann cells subjected to serum deprivation.

Results

We found that ABPPk could effectively reduce Schwann cell apoptosis caused by serum deprivation, which was comparable to NGF’s anti-apoptotic effects. ABPPk had the largest number of upregulated and downregulated differential expression genes at the earliest 0.5 h time, while NGF had fewer differential expression genes at this early stage. The significant difference at this time point between the two groups was also displayed in heatmaps. The molecular regulation of diseases and functions and canonical pathways revealed that ABPPk had more participation and advantages in the vasculature and immune system areas, especially angiogenesis regulation. Also, ABPPk demonstrated an earlier start in these molecular regulations than NGF. Furthermore, the analysis of transcription factors also illustrated that ABPPk not only had more key initial regulatory factors participating in vascular-related processes, but these also remained for a longer period. There was no significant difference in neural-related molecular regulation between the two groups.

Conclusions

Using high-throughput sequencing technology, our work unveiled the protective effects of ABPPk on Schwann cells after serum deprivation in a more comprehensive manner. These results further enrich the positive functions and molecular mechanisms of ABPPk and traditional Chinese medicine and benefit the discovery of novel therapeutic targets for peripheral nerve regeneration.

Combined Toxicity of Metal Nanoparticles: Comparison of Individual and Mixture Particles Effect

Toxicity of metal nanoparticles (NPs) are closely associated with increasing intracellular reactive oxygen species (ROS) and the levels of pro-inflammatory mediators. However, NP interactions and surface complexation reactions alter the original toxicity of individual NPs. To date, toxicity studies on NPs have mostly been focused on individual NPs instead of the combination of several species. It is expected that the amount of industrial and highway-acquired NPs released into the environment will further increase in the near future. This raises the possibility that various types of NPs could be found in the same medium, thereby, the adverse effects of each NP either could be potentiated, inhibited or remain unaffected by the presence of the other NPs. After uptake of NPs into the human body from various routes, protein kinases pathways mediate their toxicities. In this context, family of mitogen-activated protein kinases (MAPKs) is mostly efficient. Despite each NP activates almost the same metabolic pathways, the toxicity induced by a single type of NP is different than the case of co-exposure to the combined NPs. The scantiness of toxicological data on NPs combinations displays difficulties to determine, if there is any risk associated with exposure to combined nanomaterials. Currently, in addition to mathematical analysis (Response surface methodology; RSM), the quantitative-structure-activity relationship (QSAR) is used to estimate the toxicity of various metal oxide NPs based on their physicochemical properties and levels applied. In this chapter, it is discussed whether the coexistence of multiple metal NPs alter the original toxicity of individual NP. Additionally, in the part of "Toxicity of diesel emission/exhaust particles (DEP)", the known individual toxicity of metal NPs within the DEP is compared with the data regarding toxicity of total DEP mixture.

Cadmium exposure reduces invasion of the human trophoblast-derived HTR-8/SVneo cells by inhibiting cell adhesion and matrix metalloproteinase-9 secretion

Preeclampsia and intrauterine growth restriction, multisystemic disorders characterized by a shallow trophoblast invasion, have been associated with maternal cadmium (Cd) exposure. The molecular mechanisms of this association remain unknown. Cell adhesion and matrix metalloproteinase production are essential for an adequate trophoblast invasion. Thus, the aim of this study was to determine the effect of Cd exposure on invasion, adhesion, and matrix metalloproteinase-9 (MMP-9) production in the trophoblast-derived HTR-8/SVneo cell line. Cultured HTR-8/SVneo trophoblast cells were incubated with different concentrations of CdCl₂ for 6 h. Cell invasion was determined by the transwell assay, while cell adhesion was examined on collagen type I. MMP-9 release and activity were measured by ELISA and zymography, respectively. MMP-9 mRNA expression was detected by reverse-transcription polymerase chain reaction, while intracellular MMP-9 protein was assessed by Western blotting. Cd exposure significantly decreased the invasion and adhesion of HTR-8/SVneo cells. Also, MMP-9 levels and activity in the culture medium were significantly reduced after Cd incubation. In contrast, MMP-9 mRNA expression and intracellular protein levels were significantly increased. These data indicate that Cd reduces trophoblast cells invasiveness by inhibiting cell adhesion and MMP-9 secretion.

Suppression of Urokinase-Type Plasminogen Activator Receptor by Docosahexaenoic Acid Mediated by Heme Oxygenase-1 in 12-O-Tetradecanoylphorbol-13-Acetate-Induced Human Endothelial Cells

Urokinase-type plasminogen activator receptor (uPAR) plays a crucial role in inflammation and tumor metastasis. Docosahexaenoic acid (DHA), a representative omega-3 polyunsaturated fatty acid, has been shown to exhibit anti-inflammatory and anti-tumor properties. However, the mechanism by which DHA negatively regulates uPAR expression is not yet understood. The aim of this study was to investigate the effect of DHA on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced uPAR expression and potential role of heme oxygenase-1 (HO-1) in DHA-induced inhibition of uPAR in human endothelial ECV304 cells. Results showed that TPA induced uPAR expression in a time dependent manner, while DHA inhibited uPAR expression in a concentration-dependent manner. Moreover, treatment with DHA induced HO-1 expression in a time- and concentration-dependent manner. In addition, DHA-induced inhibition of uPAR expression and cell invasion in TPA-stimulated cells was reversed by si-HO-1 RNA. Induction of HO-1 by ferric protoporphyrin IX (FePP) inhibited TPA-induced uPAR expression, and this effect was abolished by treatment with the HO-1 inhibitor tin protoporphyrin IX (SnPP). Additionally, carbon monoxide, an HO-1 product, attenuated TPA-induced uPAR expression and cell invasion. Collectively, these data suggest a novel role of DHA-induced HO-1 in reducing uPAR expression and cell invasion in human endothelial ECV304 cells.

Oncogenic transformation of human benign prostate hyperplasia with chronic cadmium exposure

Experimentally, it has been proved that cadmium served as an effective carcinogen and able to induce tumors in rodents in a dose-specific manner. However, systemic evaluation of cadmium exposure for the transformation of prostatic hyperplasia into prostate cancer (PCa) is still unclear. In the present study, an attempt has been made to establish cadmium-induced human prostate carcinogenesis using an in vitro model of BPH cells. Wide range of cadmium concentrations, i.e., 1 nM, 10 nM, 100 nM and 1μM, were chronically exposed to the human BPH cells for transformation into PCa and monitored using cell and molecular biology approaches. After eight weeks of exposure, the cells showed subtle morphological changes and shifts of cell cycle in the G2M phase. Significant increase in expression of prostatic genes AR, PSA, ER-β, and 5αR with increased nuclear localization of AR and pluripotency markers Cmyc, Klf4 indicated the carcinogenic effect of Cd. Further, the BPH cells exposed to Cd showed a substantial increase in the secretion of MMP-2 and MMP-9, influencing migratory potential of the cells along with decreased expression of the p63 protein which further strengthen the progression towards carcinogenesis and aggressive tumor studies. Data from the present study state that Cd exhibited marked invasiveness in BPH cells. These observations established a connecting link of BPH towards PCa pathogenesis. Further, the study will also help in investigating the intricate pathways involved in cancer progression.

Compounds from Natural Sources as Protein Kinase Inhibitors

The advantage of natural compounds is their lower number of side-effects when compared to most synthetic substances. Therefore, over the past several decades, the interest in naturally occurring compounds is increasing in the search for new potent drugs. Natural compounds are playing an important role as a starting point when developing new selective compounds against different diseases. Protein kinases play a huge role in several diseases, like cancers, neurodegenerative diseases, microbial infections, or inflammations. In this review, we give a comprehensive view of natural compounds, which are/were the parent compounds in the development of more potent substances using computational analysis and SAR studies.

Inhibition of invadopodia formation by diosgenin in tumor cells

Diosgenin is a type of steroid extracted from the rhizome of Dioscorea plants. In traditional Chinese medicine, Dioscorea has the effect of ‘eliminating phlegm, promoting digestion, relaxing tendons, promoting blood circulation and inhibiting malaria’. Recent studies have confirmed that diosgenin exhibits a number of pharmacological effects, including antitumor activities. Through its antitumor effect, diosgenin is able to block tumor progression and increase the survival rate of patients with cancer; ultimately improving their quality of life. However, the mechanism underlying its pharmacological action remains unclear. Once tumor cells reach a metastatic phase, it can be fatal. Increased migration and invasiveness are the hallmarks of metastatic tumor cells. Invadopodia formation is key to maintaining the high migration and invasive ability of tumor cells. Invadopodia are a type of membrane structure process rich in filamentous-actin and are common in highly invasive tumor cells. In addition to actin, numerous actin regulators, including cortical actin-binding protein (Cortactin), accumulate in invadopodia. Cortactin is a microfilament actin-binding protein with special repetitive domains that are directly involved in the formation of the cortical microfilament actin cell skeleton. Cortactin is also one of the main substrates of intracellular Src-type tyrosine protein kinases and represents a highly conserved family of intracellular cortical signaling proteins. In recent years, great progress has been made in understanding the role of Cortactin and its molecular mechanism in cell motility. However, the diosgenin-Cortactin-invadopodia mechanism is still under investigation. Therefore, the present review focused on the current research on the regulation of invadopodia by diosgenin via Cortactin.

Cadmium desynchronizes neurotransmitter release in the neuromuscular junction: Key role of ROS

Cd²⁺ is one of the most widespread environmental pollutants and its accumulation in central and peripheral nervous systems leads to neurotoxicity as well as aggravation of common neurodegenerative diseases. Mechanism of the Cd²⁺ toxicity is far from being resolved. Here, using microelectrode recordings of postsynaptic responses and fluorescent redox indicators we studied the effect of Cd²⁺ in the submicromolar range on timing of neurotransmitter release and oxidative status in two functionally different compartments of the same frog motor nerve terminal. Cd²⁺ (0.1-1 μM) acting as typical voltage-gated Ca²⁺channel (VGCC) antagonist decreased neurotransmitter release in both distal and proximal parts of the nerve terminal, but in contrast to the VGCC blockers Cd²⁺(0.1-0.5 μM) desynchronized the release selectively in the distal region. The latter action of Cd²⁺ was completely prevented by inhibitor of NADPH-oxidase and antioxidants, including mitochondrial specific, as well as redox-sensitive TRPV1 channel blocker. Cd²⁺ markedly increased levels of mitochondrial reactive oxygen species (ROS) in both the distal and proximal compartments of the nerve terminal, which was associated with lipid peroxidation mainly in the distal region. Zn²⁺, whose transport systems translocate Cd²⁺, markedly enhanced the effects of Cd²⁺ on both the mitochondrial ROS levels and timing of neurotransmitter release. Furthermore, in the presence of Zn²⁺ ions, Cd²⁺ also desynchronized the neurotransmitter release in the proximal region. Thus, in synapses Cd²⁺ at very low concentrations can increase mitochondrial ROS, lipid peroxidation and disturb the timing of neurotransmitter release via a ROS/TRPV-dependent mechanism. Desynchronization of neurotransmitter release and synaptic oxidative stress could be early events in Cd²⁺ neurotoxicity.

Lipoxin A4 attenuates uric acid-activated, NADPH oxidase-dependent oxidative stress by interfering with translocation of p47phox in human umbilical vein endothelial cells

LipoxinA4 (LXA4) is a well-known key mediator of endogenous anti-inflammation and of the resolution of inflammation. Considerable oxidative stress occurs during inflammation due to the generation of reactive oxidative species (ROS). Moreover, high levels of uric acid (UA) contribute to endothelial cell dysfunction, which can promote disease-related morbidity, and NADPH oxidase-derived ROS are crucial regulatory factors in these responses. However, LXA4 also has the potential to reduce oxidative stress. The aim of the present study was to examine whether LXA4 could suppress UA-induced oxidative stress in human umbilical vein endothelial cells (HUVECs) and to investigate its mechanisms of action in vitro. HUVECs were incubated with or without LXA4, followed by the addition of UA. ROS levels were then measured using 2,7-dichlorodihydrofluorescein diacetate and lucigenin-enhanced chemiluminescence was used to evaluate NADPH oxidase activity. p47phox or p22phox small interfering (si)RNA were transfected into HUVECs and protein levels of p47phox were detected using western blot analysis. LXA4 significantly inhibited UA-induced generation of ROS to the same extent as the NADPH oxidase inhibitor, diphenyleneiodonium chloride. Notably, transfection of p47phox siRNA attenuated the generation of ROS and the activation of NADPH oxidase. Cells transfected with p22phox siRNA demonstrated a significant reduction in the expression of p47phox on the membrane. Further experiments demonstrated that LXA4 interfered with the transfer of p47phox from the cytoplasm to the cell membrane. These findings suggested that LXA4 inhibited the release of NADPH oxidase derived ROS in HUVECs stimulated by UA. A potential mechanism of action underlying this effect could be LXA4-mediated suppression of NADPH oxidase activity, leading to inhibition of p47phox translocation from the cytoplasm to the cell membrane.

Erlotinib Protects LPS-Induced Acute Lung Injury in Mice by Inhibiting EGFR/TLR4 Signaling Pathway

Epidermal growth factor receptor (EGFR) has been reported to initiate the inflammatory response, but its activation in lipopolysaccharide (LPS)-induced murine model of acute lung injury (ALI) remains unclear. In this study, we investigated the role of EGFR in the LPS-induced murine model of ALI and explored whether its inhibitor erlotinib could affect the progression of lung injury. We first detected the phosphorylated EGFR (p-EGFR)/EGFR ratio at different time points after LPS stimulation, and then different concentrations of erlotinib were used to treat mice at 1 h before LPS stimulation and collected samples at the time point of the highest p-EGFR/EGFR ratio. Lung injury indicators were detected and compared among groups. EGFR and toll-like receptor 4 (TLR4)/nuclear factor kappa B (NF-κB) signal transduction factors, including p-EGFR, p-AKT, p-ERK1/2, p-p65, tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β), were measured with western blot. We found that the mice challenged with LPS suffered from the most serious lung injury at 24 h after LPS stimulation when the p-EGFR/EGFR ratio was relatively the highest. Erlotinib significantly diminished LPS-induced exudation of total cells, neutrophils, and proteins in BALF. Both the ELISA and western blot results showed that erlotinib attenuated the expression of TNF-α and IL-1β in LPS-induced ALI in mice. Inhibition of EGFR by erlotinib downregulated the expression of p-p65 protein level as well as blocked the activation of AKT and ERK1/2 signaling pathway. Taken together, erlotinib alleviated the LPS-induced ALI in a dose-dependent manner by suppressing EGFR activation and downregulating the NF-κB-mediated secretion of proinflammatory cytokines.

A Moderate Blast Exposure Results in Dysregulated Gene Network Activity Related to Cell Death, Survival, Structure, and Metabolism

Blast exposure is common in military personnel during training and combat operations, yet biological mechanisms related to cell survival and function that coordinate recovery remain poorly understood. This study explored how moderate blast exposure influences gene expression; specifically, gene-network changes following moderate blast exposure. On day 1 (baseline) of a 10-day military training program, blood samples were drawn, and health and demographic information collected. Helmets equipped with bilateral sensors worn throughout training measured overpressure in pounds per square inch (psi). On day 7, some participants experienced moderate blast exposure (peak pressure ≥5 psi). On day 10, 3 days post-exposure, blood was collected and compared to baseline with RNA-sequencing to establish gene expression changes. Based on dysregulation data from RNA-sequencing, followed by top gene networks identified with Ingenuity Pathway Analysis, a subset of genes was validated (NanoString). Five gene networks were dysregulated; specifically, two highly significant networks: (1) Cell Death and Survival (score: 42), including 70 genes, with 50 downregulated and (2) Cell Structure, Function, and Metabolism (score: 41), including 69 genes, with 41 downregulated. Genes related to ubiquitination, including neuronal development and repair: UPF1, RNA Helicase and ATPase (UPF1) was upregulated while UPF3 Regulator of Nonsense Transcripts Homolog B (UPF3B) was downregulated. Genes related to inflammation were upregulated, including AKT serine/threonine kinase 1 (AKT1), a gene coordinating cellular recovery following TBIs. Moderate blast exposure induced significant gene expression changes including gene networks involved in (1) cell death and survival and (2) cellular development and function. The present findings may have implications for understanding blast exposure pathology and subsequent recovery efforts.

The Effects of Maternal Obesity on Porcine Placental Efficiency and Proteome

Maternal obesity is associated with impaired maternal metabolism and affects the developmental programming of the fetus. The placenta is dysfunctional when exposed to an obese intrauterine environment and can transduce and mediate detrimental maternal impacts to the fetus through mechanisms that remain largely unknown. The main objective of this study was to investigate the effects of maternal obesity on the porcine placental proteome and to analyze the deregulated proteins and potential pathways predicted to be disturbed in obese placentas, using sows with high backfat as a model of obese pregnancy. The sows were divided into two groups based on their backfat thickness: normal backfat (NBF, 17-22 mm; n = 30) and high backfat (HBF, ≥23 mm; n = 30) as the maternal obesity group. The placental tissues used for the proteomic and biochemical analyses were obtained through vaginal delivery, and the maternal blood samples used to determine the metabolic parameters were collected at day 107 of pregnancy. Our study demonstrated that HBF sows had significantly decreased placental efficiency, increased plasma-free fatty acids and triglyceride levels, and increased proinflammatory cytokines plasma levels (p < 0.05). HBF placentas had significantly higher malondialdehyde level, lower total antioxidant capacity and antioxidase activity, increased triglyceride content and enhanced proinflammatory tumor necrosis factor- α (TNF-α) and interleukin-6 (IL-6) contents (p < 0.05). Among the 4652 proteins identified using the proteomic method, 343 were quantified as differentially abundant proteins, which were involved in many vital biological processes. Based on our bioinformatic and placental biochemical analyses, we concluded that maternal obesity is associated with abnormal carbohydrate and lipid metabolism, mitochondrial dysfunction, decreased steroid hormone biosynthesis, and increased oxidative stress and inflammation in the placenta. The results of this study are undoubtedly valuable to other researchers.

Low-dose cadmium potentiates lung inflammatory response to 2009 pandemic H1N1 influenza virus in mice

Cadmium (Cd) is a toxic, pro-inflammatory metal ubiquitous in the diet that accumulates in body organs due to inefficient elimination. Responses to influenza virus infection are variable, particularly severity of pneumonia. We used a murine model of chronic low-dose oral exposure to Cd to test if increased lung tissue Cd worsened inflammation in response to sub-lethal H1N1 infection. The results show that Cd-treated mice had increased lung tissue inflammatory cells, including neutrophils, monocytes, T lymphocytes and dendritic cells, following H1N1 infection. Lung genetic responses to infection (increasing TNF-α, interferon and complement, and decreasing myogenesis) were also exacerbated. To reveal the organization of a network structure, pinpointing molecules critical to Cd-altered lung function, global correlations were made for immune cell counts, leading edge gene transcripts and metabolites. This revealed that Cd increased correlation of myeloid immune cells with pro-inflammatory genes, particularly interferon-γ and metabolites. Together, the results show that Cd burden in mice increased inflammation in response to sub-lethal H1N1 challenge, which was coordinated by genetic and metabolic responses, and could provide new targets for intervention against lethal inflammatory pathology of clinical H1N1 infection.

Biomarkers of blood cadmium and incidence of cardiovascular events in non-smokers: results from a population-based proteomics study

BACKGROUND

Cadmium is a toxic metal with multiple adverse health effects, including risk of cardiovascular disease (CVD). The mechanistic link between cadmium and CVD is unclear. Our aim was to examine the associations between blood cadmium (B-Cd) and 88 potential protein biomarkers of CVD.

METHODS

B-Cd and 88 plasma proteins were measured in a community-based prospective cohort, the Malmö Diet and Cancer study. The primary analysis was performed in never smokers (n = 1725). Multiple linear regression was used with adjustments for age and sex, and correction for multiple comparisons using the false discovery rate method. Proteins significantly associated with B-Cd were replicated in long-term former smokers (n = 782). Significant proteins were then studied in relation to incidence of CVD (i.e., coronary events or ischemic stroke) in never smokers.

RESULTS

Fifteen proteins were associated with B-Cd in never smokers. Eight of them were replicated in long-term former smokers. Kidney injury molecule-1, fibroblast growth factor-23 (FGF23), tumor necrosis factor receptor-2, matrix metalloproteinase-12, cathepsin L1, urokinase plasminogen activator receptor, C-C motif chemokine-3 (CCL3), and chemokine (C-X3-C motif) ligand-1 were associated with B-Cd both in never smokers and long-term former smokers. Except for CCL3 and FGF23, these proteins were also significantly associated with incidence of CVD.

CONCLUSIONS

B-Cd in non-smokers was associated with eight potential plasma biomarkers of CVD and kidney injury. The results suggest pathways for the associations between B-Cd and CVD and kidney injury.

Implication of oxidative stress in the pathogenesis of systemic sclerosis via inflammation, autoimmunity and fibrosis

Systemic sclerosis is an autoimmune disorder characterized by inflammation and a progressive fibrosis affecting the skin and visceral organs. Over the last two decades, it became clear that oxidative stress plays a key role in its pathogenesis. In this review, we highlighted the role of ROS in the various pathological components of systemic sclerosis, namely the inflammatory, the autoimmune and the fibrotic processes. We also discussed how these pathological processes can induce ROS overproduction, thus maintaining a vicious circle. Finally, we summarized the therapeutic approaches targeting oxidative stress tested in systemic sclerosis, in cells, animal models and patients.

The Emerging Role of Estrogens in Thyroid Redox Homeostasis and Carcinogenesis

Reactive oxygen species (ROS) are the most critical class of free radicals or reactive metabolites produced by all living organisms. ROS regulate several cellular functions through redox-dependent mechanisms, including proliferation, differentiation, hormone synthesis, and stress defense response. However, ROS overproduction or lack of appropriate detoxification is harmful to cells and can be linked to the development of several diseases, such as cancer. Oxidative damage in cellular components, especially in DNA, can promote the malignant transformation that has already been described in thyroid tissue. In thyrocyte physiology, NADPH oxidase enzymes produce large amounts of ROS that are necessary for hormone biosynthesis and might contribute to the high spontaneous mutation rate found in this tissue. Thyroid cancer is the most common endocrine malignancy, and its incidence is significantly higher in women than in men. Several lines of evidence suggest the sex hormone estrogen as a risk factor for thyroid cancer development. Estrogen in turn, besides being a potent growth factor for both normal and tumor thyroid cells, regulates different mechanisms of ROS generation. Our group demonstrated that the thyroid gland of adult female rats exhibits higher hydrogen peroxide (H₂O₂) production and lower enzymatic antioxidant defense in comparison with male glands. In this review, we discuss the possible involvement of thyroid redox homeostasis and estrogen in the development of thyroid carcinogenesis.

Dynamic protein expression of NF-κB following rat intracerebral hemorrhage and its association with apoptosis

The aim of the present study was to evaluate the dynamic protein expression of nuclear factor (NF)-κB and apoptosis in the cerebral tissue surrounding hematoma following intracerebral hemorrhage (ICH) in rats. A total of 80 healthy male Wistar rats were divided into a sham-surgery group and an ICH group. The ICH model was established by injecting autogenous non-heparin anticoagulant arterial blood into the caudate putamen. NF-κB levels were assessed by immunohistochemistry at different time points subsequent to surgery, and apoptosis condition was investigated by terminal deoxynucleotidyl-transferase-mediated dUTP nick end labeling. Different levels of NF-κB were expressed in the cerebral tissue around the ICH at each time point in the ICH group. NF-κB protein expression was detected at 3 h following hemorrhage, mainly in the cytoplasm. Following 6 h, NF-κB was identified in the nucleus. Its expression peaked at 72 h following hemorrhage, and persisted for 5 days. Apoptosis was observed 6 h following hemorrhage, and had increased significantly by 12 h. The rate of apoptosis continued to rise from 72-120 h following hemorrhage. Correlation analysis revealed a significant positive correlation between NF-κB expression and apoptosis (r=0.753; P<0.01). The enhancement of NF-κB expression and apoptosis around ICH, and the significant positive correlation between NF-κB expression and apoptosis, indicates that NF-κB activation may enhance cerebral apoptosis in rats following ICH.

Association of NF-κB and AP-1 with MMP-9 Overexpression in 2-Chloroethanol Exposed Rat Astrocytes

Subacute poisoning of 1,2-dichloroethane (1,2-DCE) has become a serious occupational problem in China, and brain edema is its main pathological consequence, but little is known about the underlying mechanisms. As the metabolite of 1,2-DCE, 2-chloroethanol (2-CE) is more reactive, and might play an important role in the toxic effects of 1,2-DCE. In our previous studies, we found that matrix metalloproteinases-9 (MMP-9) expression was enhanced in mouse brains upon treatment with 1,2-DCE, and in rat astrocytes exposed to 2-CE. In the present study, we analyzed the association of nuclear factor kappa B (NF-κB) and activator protein-1 (AP-1) with MMP-9 overexpression in astrocytes treated with 2-CE. MMP-9, p65, c-Jun, and c-Fos were significantly upregulated by 2-CE treatment, which also enhanced phosphorylation of c-Jun, c-Fos and inhibitor of κBα (IκBα), and nuclear translocation of p65. Furthermore, inhibition of IκBα phosphorylation and AP-1 activity with the specific inhibitors could attenuate MMP-9 overexpression in the cells. On the other hand, inhibition of p38 mitogen-activated protein kinase (p38 MAPK) signaling pathway suppressed the activation of both NF-κB and AP-1 in 2-CE-treated astrocytes. In conclusion, MMP-9 overexpression induced by 2-CE in astrocytes could be mediated at least in part through the p38 signaling pathway via activation of both NF-κB and AP-1. This study might provide novel clues for clarifying the mechanisms underlying 1,2-DCE associated cerebral edema.

Andrographolide Antagonizes TNF-α-Induced IL-8 via Inhibition of NADPH Oxidase/ROS/NF-κB and Src/MAPKs/AP-1 Axis in Human Colorectal Cancer HCT116 Cells

Andrographis paniculata Nees is used as a functional food in Japan, Korea, India, and China. Andrographolide, a naturally occurring phytochemical identified in Andrographis paniculata, has been discovered to present anti-inflammatory and anticancer activities. Highly expressed interleukin (IL-8) has been detected in colorectal cancer and is implicated in angiogenesis. However, the effect and molecular mechanisms of IL-8 expression by andrographolide remain obscure in human colorectal cancer cells. The present study was aimed to investigate the effects of andrographolide on TNF-α-induced IL-8 expression and its underlying mechanisms. We found that andrographolide concentration-dependently inhibited TNF-α-induced IL-8 mRNA (2.23 ± 0.15 fold at 20 μM) and protein expression (4.78 ± 0.31 fold at 20 μM) and reduced the IL-8 transcriptional activity (2.59 ± 0.25 fold at 20 μM). TNF-α stimulated the membrane translocation of p47^phox to activate reactive oxygen species (ROS)-producing NADPH oxidase (NOX). Furthermore, TNF-α induced Src and MAPKs (Erk1/2, p38 MAPK) phosphorylation, as well as NF-κB and AP-1 binding activities. We found that NF-κB and AP-1 were the critical transcription factors for TNF-α-induced IL-8 expression. Specific inhibitors and mutagenesis studies indicated that Src, Erk1/2, and p38 MAPK are related to TNF-α-induced IL-8. NOX-derived ROS and Src/MAPKs (Erk1/2 and p38 MAPK) functioned as upstream activators of NF-κB and AP-1, respectively. Taken together, andrographolide antagonizes TNF-α-induced IL-8 via inhibition of NADPH oxidase/ROS/NF-κB and Src/MAPKs/AP-1 signaling pathways in HCT116 colorectal cancer cells and then suppresses angiogenesis in the tumor microenvironment.

Flavocoxid, a Natural Antioxidant, Protects Mouse Kidney from Cadmium-Induced Toxicity

Background

Cadmium (Cd), a diffused environmental pollutant, has adverse effects on urinary apparatus. The role of flavocoxid, a natural flavonoid with antioxidant activity, on the morphological and biochemical changes induced in vivo by Cd in mice kidney was evaluated.

Methods

C57 BL/6J mice received 0.9% NaCl alone, flavocoxid (20 mg/kg/day i.p.) alone, Cd chloride (CdCl₂) (2 mg/kg/day i.p.) alone, or CdCl₂ plus flavocoxid (2 mg/kg/day i.p. plus 20 mg/kg/day i.p.) for 14 days. The kidneys were processed for biochemical, structural, ultrastructural, and morphometric evaluation.

Results

Cd treatment alone significantly increased urea nitrogen and creatinine, iNOS, MMP-9, and pERK 1/2 expression and protein carbonyl; reduced GSH, GR, and GPx; and induced structural and ultrastructural changes in the glomeruli and in the tubular epithelium. After 14 days of treatment, flavocoxid administration reduced urea nitrogen and creatinine, iNOS, MMP-9, and pERK 1/2 expression and protein carbonyl; increased GSH, GR, and GPx; and showed an evident preservation of the glomerular and tubular structure and ultrastructure.

Conclusions

A protective role of flavocoxid against Cd-induced oxidative damages in mouse kidney was demonstrated for the first time. Flavocoxid may have a promising antioxidant role against environmental Cd harmful effects on glomerular and tubular lesions.

Dose dependent effects of cadmium on tumor angiogenesis

Angiogenesis is crucial for tumor growth and metastasis. Cadmium (Cd) exposure is associated with elevated cancer risk and mortality. Such association is, at least in part, attributable to Cd-induced tumor angiogenesis. Nevertheless, the reported effects of Cd on tumor angiogenesis appear to be either stimulatory or inhibitory, depending on the concentrations. Ultra-low concentrations of Cd (<0.5 μM) inhibit endothelial nitric oxide synthase activation, leading to reduced endothelial nitric oxide production and attenuated tumor angiogenesis. In contrast, low-lose Cd (1-10 μM) up-regulates vascular endothelial growth factor (VEGF)-mediated tumor angiogenesis by exerting sub-apoptotic levels of oxidative stress on both tumor cells and endothelial cells (ECs). The consequent activation of protein kinase B/Akt, nuclear factor-κB, and mitogen-activated protein kinase signaling cascades mediate the increased secretion of VEGF by tumor cells and the up-regulated VEGF receptor-2 expression in ECs. Furthermore, Cd in high concentrations (>10 μM) induces EC apoptosis via the activation of caspase-3, resulting in destruction of tumor vasculature. In this review, we summarize the current knowledge concerning the roles of Cd in tumor angiogenesis, with a focus on molecular mechanisms underlying the dose dependent effects of Cd on various EC phenotypes.

The Antagonistic Effect of Selenium on Cadmium-Induced Damage and mRNA Levels of Selenoprotein Genes and Inflammatory Factors in Chicken Kidney Tissue

Selenium (Se) is a necessary trace mineral in the diet of humans and animals. Cadmium (Cd) is a toxic heavy metal that can damage animal organs, especially the kidneys. Antagonistic interactions between Se and Cd have been reported in previous studies. However, little is known about the effects of Se against Cd toxicity and on the mRNA levels of 25 selenoprotein genes and inflammatory factors in chicken kidneys. In the current study, we fed chickens with a Se-treated, Cd-treated, or Se/Cd treated diet for 90 days. We then analyzed the mRNA expression of inflammatory factors (including prostaglandin E synthase (PTGES), nuclear factor-kappa B (NF-κB), tumor necrosis factor-α (TNF-α), and cyclooxygenase-2 (COX-2)) and 25 selenoprotein genes (Gpx1, Gpx2, Gpx3, Gpx4, Txnrd1, Txnrd2, Txnrd3, Dio1, Dio2, Dio3, SPS2, Sepp1, SelPb, Sep15, Selh, Seli, Selm, Selo, Sels, Sepx1, Selu, Selk, Selw, Seln, Selt). The results demonstrated that Cd exposure increased the Cd content in the chicken kidneys, renal tubular epithelial cells underwent denaturation and necrosis, and the tubules became narrow or disappeared. However, Se supplementation reduced the Cd content in chicken kidneys and induced normal development of renal tubular epithelial cells. In addition, we also observed that Se alleviated the Cd-induced increase in the mRNA levels of inflammatory factors and ameliorated the Cd-induced downtrend in the mRNA levels of 25 selenoprotein genes in chicken kidneys.

Derangement of intestinal epithelial cell monolayer by dietary cholesterol oxidation products

The emerging role of the diet in the incidence of intestinal inflammatory diseases has stimulated research on the influence of eating habits with pro-inflammatory properties in inducing epithelial barrier disturbance. Cholesterol oxidation products, namely oxysterols, have been shown to promote and sustain oxidative/inflammatory reactions in human digestive tract. This work investigated in an in vitro model the potential ability of a combination of dietary oxysterols representative of a hyper-cholesterol diet to induce the loss of intestinal epithelial layer integrity. The components of the experimental mixture were the main oxysterols stemming from heat-induced cholesterol auto-oxidation, namely 7-ketocholesterol, 5α,6α-and 5β,6β-epoxycholesterol, 7α- and 7β-hydroxycholesterol. These compounds added to monolayers of differentiated CaCo-2 cells in combination or singularly, caused a time-dependent induction of matrix metalloproteinases (MMP)-2 and -9, also known as gelatinases. The hyperactivation of MMP-2 and -9 was found to be associated with decreased levels of the tight junctions zonula occludens-1 (ZO-1), occludin and Junction Adhesion Molecule-A (JAM-A). Together with such a protein loss, particularly evident for ZO-1, a net perturbation of spatial localization of the three tight junctions was observed. Cell monolayer pre-treatment with the selective inhibitor of MMPs ARP100 or polyphenol (-)-epicathechin, previously shown to inhibit NADPH oxidase in the same model system, demonstrated that the decrease of the three tight junction proteins was mainly a consequence of MMPs induction, which was in turn dependent on the pro-oxidant property of the oxysterols investigated. Although further investigation on oxysterols intestinal layer damage mechanism is to be carried on, the consequent - but incomplete - prevention of oxysterols-dependent TJs alteration due to MMPs inhibition, avoided the loss of scaffold protein ZO-1, with possible significant recovery of intestinal monolayer integrity.

Propyl Gallate Exerts an Antimigration Effect on Temozolomide-Treated Malignant Glioma Cells through Inhibition of ROS and the NF-κB Pathway

In this study, we demonstrated that temozolomide (TMZ) and propyl gallate (PG) combination enhanced the inhibition of migration in human U87MG glioma cells. PG inhibited the TMZ-induced reactive oxygen species (ROS) generation. The mitochondrial complex III and NADPH oxidase are two critical sites that can be considered to regulate antimigration in TMZ-treated U87MG cells. PG can enhance the antimigration effect of TMZ through suppression of metalloproteinase-2 and metalloproteinase-9 activities, ROS generation, and the NF-κB pathway and possibly provide a novel prospective strategy for treating malignant glioma.

E-cadherin expression increases cell proliferation by regulating energy metabolism through nuclear factor-κB in AGS cells

β-Catenin is a central player in Wnt signaling, and activation of Wnt signaling is associated with cancer development. E-cadherin in complex with β-catenin mediates cell-cell adhesion, which suppresses β-catenin-dependent Wnt signaling. Recently, a tumor-suppressive role for E-cadherin has been reconsidered, as re-expression of E-cadherin was reported to enhance the metastatic potential of malignant tumors. To explore the role of E-cadherin, we established an E-cadherin-expressing cell line, EC96, from AGS cells that featured undetectable E-cadherin expression and a high level of Wnt signaling. In EC96 cells, E-cadherin re-expression enhanced cell proliferation, although Wnt signaling activity was reduced. Subsequent analysis revealed that nuclear factor-κB (NF-κB) activation and consequent c-myc expression might be involved in E-cadherin expression-mediated cell proliferation. To facilitate rapid proliferation, EC96 cells enhance glucose uptake and produce ATP using both mitochondria oxidative phosphorylation and glycolysis, whereas AGS cells use these mechanisms less efficiently. These events appeared to be mediated by NF-κB activation. Therefore, E-cadherin re-expression and subsequent induction of NF-κB signaling likely enhance energy production and cell proliferation.

Planarians as models of cadmium-induced neoplasia provide measurable benchmarks for mechanistic studies

Bioassays of planarian neoplasia highlight the potential of these organisms as useful standards to assess whether environmental toxins such as cadmium promote tumorigenesis. These studies complement other investigations into the exceptional healing and regeneration of planarians - processes that are driven by a population of active stem cells, or neoblasts, which are likely transformed during planarian tumor growth. Our goal was to determine if planarian tumorigenesis assays are amenable to mechanistic studies of cadmium carcinogenesis. To that end we demonstrate, by examining both counts of cell populations by size, and instances of mitosis, that the activity of the stem cell population can be monitored. We also provide evidence that specific biomodulators can affect the potential of planarian neoplastic growth, in that an inhibitor of metalloproteinases effectively blocked the development of the lesions. From these results, we infer that neoblast activity does respond to cadmium-induced tumor growth, and that metalloproteinases are required for the progression of cancer in the planarian.