1,3-Dichloro-2-propanol evokes inflammation and apoptosis in BV-2 microglia via MAPKs and NF-κB signaling pathways mediated by reactive oxygen species

Newly discovered developmental and ovarian toxicity of 3-monochloro-1,2-propanediol in Drosophila melanogaster and cyanidin-3-O-glucoside's protective effect

3-Monochloro-1,2-propanediol (3-MCPD) is a pervasive environmental pollutant that is unintentionally produced during industrial production and food processing. Although some studies reported the carcinogenicity and male reproduction toxicity of 3-MCPD thus far, it remains unexplored whether 3-MCPD hazards to female fertility and long-term development. In this study, the model Drosophila melanogaster was employed to evaluate risk assessment of emerging environmental contaminants 3-MCPD at various levels. We found that flies on dietary exposure to 3-MCPD incurred lethality in a concentration- and time-dependent way and interfered with metamorphosis and ovarian development, resulting in developmental retardance, ovarian deformity and female fecundity disorders. Mechanistically, 3-MCPD caused redox imbalance observed as a drastically increased oxidative status in ovaries, confirmed by increased reactive oxygen species (ROS) and decreased antioxidant activities, which is probably responsible for female reproductive impairments and developmental retardance. Intriguingly, these defects can be substantially prevented by a natural antioxidant, cyanidin-3-O-glucoside (C3G), further confirming a critical role of ovarian oxidative damage in the developmental and reproductive toxicity of 3-MCPD. The present study expanded the findings that 3-MCPD acts as a developmental and female reproductive toxicant, and our work provides a theoretical basis for the exploitation of a natural antioxidant resource as a dietary antidote for the reproductive and developmental hazards of environmental toxicants that act via increasing ROS in the target organ.

1,3-Dichloro-2-propanol induced ferroptosis through Nrf2/ARE signaling pathway in hepatocytes

1,3-Dichloro-2-propanol (1,3-DCP) is a representative chloropropane environmental contaminant with multiple toxicities. Ferroptosis is a novel iron-dependent form of regulated cell death that is closely associated with the accumulation of lipid peroxides, Fe²⁺ and reactive oxygen species (ROS). In this study, we found that 1,3-DCP could induce mouse liver injury via ferroptosis. Administrating of C57BL/6J mice with 12.5, 25, and 50 mg/kg 1,3-DCP for 4 weeks via oral gavage, the data showed that 1,3-DCP exposure led to the pathological changes in mouse livers, remarkably induced accumulation of malondialdehyde (MDA) and Iron, reduction of glutathione (GSH), and changed in the expression of ferroptosis marker proteins glutathione peroxidase 4 (GPX4) and acyl-CoA synthetase-4 (ACSL4). Then, we also proved the results with HepG2 cells in vitro. The data showed that treatment 1,3-DCP significantly triggered the ferroptosis in vitro. Furthermore, we found that the ferroptosis-related signal pathways were significantly activated in mice livers and HepG2 cells in response to 1,3-DCP exposure. The data showed that 1,3-DCP induced ferroptosis by inhibiting nuclear factor erythroid 2-related factor 2 (Nrf2) translocation into nuclear and thereby suppressing the expression of its downstream target proteins including GPX4, ferritin heavy chain (FTH), ferroportin (FPN), cystine/glutamate transporter xCT (SLC7A11), and heme oxygenase 1 (HO-1). Taken together, our findings confirmed that 1,3-DCP induced ferroptosis via the Nrf2/ARE signaling pathway in hepatocytes. Our works provide new toxicity mechanisms of 1,3-DCP with ferroptosis on hepatocytes injury.

1,3-Dichloro-2-propanol-Induced Renal Tubular Cell Necroptosis through the ROS/RIPK3/MLKL Pathway

1,3-Dichloro-2-propanol (1,3-DCP), as a food pollutant, exists in a variety of foods. Studies have shown that it has nephrotoxicity. In the study, we found that 1,3-DCP caused renal injury with necroptosis in C57BL/6J mice. The mechanism of 1,3-DCP-caused nephrotoxicity was further explored in NRK-52E cells in vitro. We found that 1,3-DCP caused cell necroptosis with the increase in lactate dehydrogenase (LDH) levels and the expressions of RIPK3 and MLKL. But pretreatment with a ROS inhibitor N-acetyl-l-cysteine (NAC), a RIPK3 inhibitor GSK'872, or RIPK3 gene silencing alleviated 1,3-DCP-induced cell necroptosis. The data indicated that 1,3-DCP induced necroptosis through the ROS/RIPK3/MLKL pathway in NRK-52E cells. In further mechanistic studies, we explored how 1,3-DCP induced ROS production. We found that 1,3-DCP inhibited the expressions of nuclear and cytoplasmic Nrf2. But pretreatment with an Nrf2 activator dimethyl fumarate (DMF) up-regulated the expressions of nuclear and cytoplasmic Nrf2 and down-regulated ROS levels and RIPK3 and MLKL expressions. We also examined the effects of mitophagy on 1,3-DCP-induced ROS. The data manifested that 1,3-DCP suppressed mitophagy in NRK-52E cells by decreasing LC3-II, Pink1, and Parkin levels, increasing p62 levels, and decreasing colocalization of LC3 and Mito-Tracker Red. Pretreatment with an autophagy activator rapamycin (Rapa) decreased 1,3-DCP-induced ROS. Taken together, our data identified that 1,3-DCP caused renal necroptosis through the ROS/RIPK3/MLKL pathway.

History in Perspective: The Prime Pathological Players and Role of Phytochemicals in Alzheimer’s Disease

Alzheimer's disease is a steadily progressive, irreversible neurological disorder that is most frequently categorized under the umbrella term "neurodegeneration". Several attempts are underway to clarify the pathogenic mechanisms, identify the aetiologies, and determine a pathway by which the therapeutic steps can be implemented. Oxidative stress is one of the pathogenic processes, which is commonly believed to be associated with neurodegenerative diseases. Accumulation of extracellular amyloid-β protein (Aβ), hyperphosphorylation of tau, initiation of neurometabolic reactions characterized by the loss of neuronal function and synaptic failure, and decreased or lost learning capability and memory function are the most central neuropathological characteristics of AD. According to the amyloid cascade hypothesis, the enhanced deposition of Aβ deposits and neurofibrillary tangles due to hyperphosphorylation of Tau activates the cascade reactions in the brain. These reactions affect the synaptic activity and activation of microglia, which results in neuroinflammation due to enhanced immune function. Plant-based phytochemicals have also been used long ago against several diseases. Phytoconstituents play a significant neuroprotective property by preventing the pathophysiology of the disease. In this review, we have discussed the formation and crosstalk between amyloid and tau pathologies as well as the effect of neuroinflammation on the progression of AD. We have specifically focused on the formation of NFT, β-amyloids, inflammation, and pathophysiology of AD and the role of phytochemicals in the prevention of AD.

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AD is an insidious, slowly progressive, and neurodegenerative disorder.

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Common symptoms are memory loss, difficulty in recalling, and understanding.

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β-amyloids and Neurofibrillary tangles are the main factors in AD pathogenesis.

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Activated microglia and oxidative stress have different effects on AD progression.

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Phytochemicals show a key role against AD by inhibiting several pathways.

The role of PGC-1α and metabolic signaling pathway in kidney injury following chronic administration with 3-MCPD as a food processing contaminant

3-Monochloropropane-1,2-diol (3-MCPD) as a byproduct of food processing and a carcinogenic agent has attracted much attention in the last decades. Kidney is the main target organ that is sensitive to the toxicity of 3-MCPD. Due to limited evidence about possible 3-MCPD toxicity, we design an investigation to determine the role of mitochondrial biogenesis following chronic oral administration of 3-MCPD (2, 4, 8 and 32 mg/kg) for 2 months in male C57 mice. The present study evaluated the affects of 3-MCPD in modulating metabolic signalling which is associated with Il-18, PGC-1α, Nrf-2 and Sir3 which are the major transcription factors. Our data confirms controversial behaviors after chronic exposure with 3-MCPD. Over expression of the PGC-1α and Sir3 and IL-18 were observed after exposure with 2,4 & 8 mg kg^-1  day^-1 of 3-MCPD. In front, PGC-1α down-regulation occurs at the highest dose (32 mg/kg) resulted in kidney injury. Based on the findings, PGC-1α plays an important role in the restoration of the mitochondrial function during the recovery from chronic kidney injury. We suggest that the PGC-1α can be consider as a therapeutic target in prevention and treatment of kidney injury after chronic exposure of 3-MCPD. PRACTICAL APPLICATIONS: 3-Monochloropropane-1, 2-diol (3-MCPD) existed in several foods, can induce nephrotoxicity, progressive nephropathy and renal tubule dilation following acute and chronic exposure. It revealed that 3-MCPD toxicity is related to metabolites which can cause oxidative stress and activation of cell death signaling. It seems that cytotoxicity of 3-MCPD has disruptive effect on kidney cells due to rise in ROS production and decrease in mitochondrial membrane permeability. These effects can lead to MPT pore opening, cytochrome c release and activation of programed cell death signaling pathway. Therefore, present study was investigated the role of PGC-1a and the metabolic signaling involved in 3-MCPD-induced nephrotoxicity for the first time. Our data revealed that up-regulation of mitochondrial biogenesis following chronic exposure with 3-MCPD accelerates recovery of mitochondrial and cellular function in kidney by deacetylation of histones, overexpression of transcription factors (PGC-1α, Nrf-2, and Sir3) and maintaining cellular homeostasis.

Interaction of NF-κB and Wnt/β-catenin Signaling Pathways in Alzheimer's Disease and Potential Active Drug Treatments

The most important neuropathological features of Alzheimer's disease (AD) are extracellular amyloid-β protein (Aβ) deposition, tau protein hyperphosphorylation and activation of neurometabolic reaction in the brain accompanied by neuronal and synaptic damage, and impaired learning and memory function. According to the amyloid cascade hypothesis, increased Aβ deposits in the brain to form the core of the senile plaques that initiate cascade reactions, affecting the synapses and stimulating activation of microglia, resulting in neuroinflammation. A growing number of studies has shown that NF-κB and Wnt/β-catenin pathways play important roles in neurodegenerative diseases, especially AD. In this review, we briefly introduce the connection between neuroinflammation-mediated synaptic dysfunction in AD and elaborated on the mechanism of these two signaling pathways in AD-related pathological changes, as well as their interaction. Based on our interest in natural compounds, we also briefly introduce and conduct preliminary screening of potential therapeutics for AD.

Long-term in vitro effects of exposing the human HK-2 proximal tubule cell line to 3-monochloropropane-1,2-diol

3-Monochloropropane-1,2-diol (3-MCPD) is a food processing contaminant in the U.S. food supply, detected in infant formula. In vivo rodent model studies have identified a variety of possible adverse outcomes from 3-MCPD exposure including renal effects like increased kidney weights, tubular hyperplasia, kidney tubular necrosis, and chronic progressive nephropathy. Given the lack of available in vivo toxicological assessments of 3-MCPD in humans and the limited availability of in vitro human cell studies, the health effects of 3-MCPD remain unclear. We used in vitro human proximal tubule cells represented by the HK-2 cell line to compare short- and long-term consequences to continuous exposure to this compound. After periodic lengths of exposure (0-100 mM) ranging from 1 to 16 days, we evaluated cell viability, mitochondrial integrity, oxidative stress, and a specific biomarker of proximal tubule injury, Kidney Injury Molecule-1 (KIM-1). Overall, we found that free 3-MCPD was generally more toxic at high concentrations or extended durations of exposure, but that its overall ability to induce cell injury was limited in this in vitro system. Further experiments will be needed to conduct a comprehensive safety assessment in infants who may be exposed to 3-MCPD through consumption of infant formula, as human renal physiology changes significantly during development.

Targeting vascular endothelial growth factor ameliorates PMMA-particles induced inflammatory osteolysis in murine calvaria

Cytokines and growth factors mediate inflammatory osteolysis in response to particles released from bone implants. However, the mechanism by which this process develops is not entirely clear. Blood vessels and related factors may be required to deliver immune cells and soluble factors to the injury site. Therefore, in the current study we investigated if, vascular endothelial growth factor (VEGF), which is required for angiogenesis, mediates polymethylmethacrylate (PMMA) particles-induced osteolysis. Using bone marrow derived macrophages (BMMs) and ST2 stromal cell line, we show that PMMA particles increase VEGF expression. Further, using a murine calvarial osteolysis model, we found that PMMA injection over calvaria induce significant increase in VEGF expression as well as new vessel formation, represented by von Willebrand factor (vWF) staining. Co-treatment using a VEGF-neutralizing antibody abrogated expression of vWF, indicating decreased angiogenesis. Finally, VEGF neutralizing antibody reduced expression of Tumor necrosis factor (TNF) and decreased osteoclastogenesis induced by PMMA particles in calvariae. This work highlights the significance of angiogenesis, specifically VEGF, as key driver of PMMA particle-induced inflammatory osteolysis, inhibition of which attenuates this response.

Thermal processing food-related toxicants: a review

Heterocyclic aromatic amines, acrylamide, 5-hydroxymethylfurfural, furan, polycyclic aromatic hydrocarbons, nitrosamines, acrolein, chloropropanols and chloroesters are generated toxicants formed in some foodstuffs, mainly starchy and protein-rich food during thermal treatment such as frying, roasting and baking. The formation of these chemical compounds is associated with development of aromas, colors and flavors. One of the challenges facing the food industry today is to minimize these toxicants without adversely affecting the positive attributes of thermal processing. To achieve this objective, it is essential to have a detailed understanding of the mechanism of formation of these toxicants in processed foods. All reviewed toxicants in that paper are classified as probable, possible or potential human carcinogens and have been proven to be carcinogenic in animal studies. The purpose of that review is to summarize some of the most frequent occurring heat-generated food toxicants during conventional heating, their metabolism and carcinogenicity. Moreover, conventional and microwave heating were also compared as two different heat treatment methods, especially how they change food chemical composition and which thermal food toxicants are formed during specific method.

Alterations of antioxidant indexes and inflammatory cytokine expression aggravated hepatocellular apoptosis through mitochondrial and death receptor-dependent pathways in Gallus gallus exposed to arsenic and copper

In this study, we sought to investigate the effects of sub-chronic exposure of arsenic (As) and copper (Cu) on oxidative stress, inflammatory response, and mitochondria and death receptor apoptosis pathways in chicken liver. Seventy-two 1-day-old male Hy-line chickens were treated with basal diet, 30 mg/kg arsenic trioxide (As₂O₃), or/and 300 mg/kg copper sulfate (CuSO₄) for 4, 8, and 12 weeks. Study revealed that exposure to As or/and Cu undermined the antioxidant function and increased lipid peroxidation. Worse yet, liver cell swollen, vacuolar degeneration, and inflammatory cell infiltration were accompanied by an increase of the nuclear factor-κB (NF-κB) and its downstream inflammation-related genes after exposure to As or/and Cu. Furthermore, mitochondria swollen and chromatin condensation were found in As and Cu groups, and hepatocyte nuclear membrane rupture and markedly increased (P < 0.01) apoptosis index were observed in As combined with Cu group. Meanwhile, the transcription and protein expression levels of Bcl-2-associated X protein (Bax), p53, cytochrome c (Cyt c), and caspase-3, 8, 9 were upregulated and B cell lymphoma-2 (Bcl-2) was downregulated in As, Cu, and As + Cu groups in the liver tissues (P < 0.05, P < 0.01). Our results indicated that exposure to As or/and Cu could lead to oxidative stress, inflammatory response, and tissue damage and aggravate hepatocellular apoptosis through mitochondrial and death receptor-dependent pathways in chicken liver. And As and Cu showed a possible synergistic relationship in liver damage.