Ochratoxin A induces ERK1/2 phosphorylation-dependent apoptosis through NF-κB/ERK axis in human proximal tubule HK-2 cell line

Ochratoxin A in Poultry Supply Chain: Overview of Feed Occurrence, Carry-Over, and Pathognomonic Lesions in Target Organs to Promote Food Safety

Ochratoxin A (OTA) is a mycotoxin produced by fungi species belonging to the genera Aspergillus spp. and Penicillium spp. The proliferation of OTA-producing fungal species may occur due to inadequate practices during both the pre-harvest and post-harvest stages of feed. Consequently, poultry species may be exposed to high concentrations of this mycotoxin that can be transferred to animal tissues due to its carry-over, reaching dangerous concentrations in meat and meat products. Therefore, this review aims to propose a comprehensive overview of the effects of OTA on human health, along with data from global studies on the prevalence and concentrations of this mycotoxin in avian feeds, as well as in poultry meat, edible offal, and eggs. Moreover, the review examines significant gross and histopathological lesions in the kidneys and livers of poultry linked to OTA exposure. Finally, the key methods for OTA prevention and decontamination of feed are described.

Ochratoxin A and Its Role in Cancer Development: A Comprehensive Review

Background: Ochratoxin A (OTA) is widely recognized for its broad spectrum of toxic effects and is classified as a potential human carcinogen, placed in group 2B by the International Agency for Research on Cancer (IARC). Its presence in food and beverages poses a significant health hazard. Extensive research has documented the efficient absorption and distribution of OTA throughout the body via the bloodstream and tissues, underscoring the associated health risk. Additionally, ongoing studies aim to clarify the link between OTA exposure and carcinogenesis. The obtained results indicate a strong correlation between OTA and renal cell carcinoma (RCC), with potential associations with other malignancies, including hepatocellular carcinoma (HCC), gallbladder cancer (GBC), and squamous cell carcinoma (SCC). OTA is implicated in oxidative stress, lipid peroxidation, apoptosis, DNA damage, adduct formation, miRNA deregulation, and distributions in the cell cycle, all of which may contribute to carcinogenesis. Conclusions: Despite significant research efforts, the topic remains inexhaustible and requires further investigation. The obtained results do not yield definitive conclusions, potentially due to species-specific differences in the animal models used and challenges in extrapolating these results to humans. In our review, we delve deeper into the potential mechanisms underlying OTA-induced carcinogenesis and discuss existing limitations, providing directions for future research.

Central role of Sigma-1 receptor in ochratoxin A-induced ferroptosis

Ochratoxin A (OTA), a secondary fungal metabolite known for its nephrotoxic effects, is prevalent in various feeds and food items. Our recent study suggests that OTA-induced nephrotoxicity is linked to the Sigma-1 receptor (Sig-1R)-mediated mitochondrial pathway apoptosis in human proximal tubule epithelial-originated kidney-2 (HK-2) cells. However, the contribution of Sig-1R to OTA-induced nephrotoxicity involving other forms of regulated cell death, such as ferroptosis, remains unexplored. In this investigation, cell viability, malondialdehyde (MDA) levels, glutathione (GSH) levels, and protein expressions in HK-2 cells treated with OTA and/or Ferrostatin-1/blarcamesine hydrochloride/BD1063 dihydrochloride were assessed. The results indicate that a 24 h-treatment with 1 μM OTA significantly induces ferroptosis by inhibiting Sig-1R, subsequently promoting nuclear receptor coactivator 4 (NCOA4), long-chain fatty acid-CoA ligase 4 (ACSL4), arachidonate 5-lipoxygenase (ALOX5), autophagy protein 5 (ATG5), and ATG7, inhibiting ferritin heavy chain (FTH1), solute carrier family 7 member 11 (SLC7A11/xCT), glutathione peroxidase 4 (GPX4), peroxiredoxin 6 (PRDX6), and ferroptosis suppressor protein 1 (FSP1), reducing GSH levels, and increasing MDA levels (P < 0.05). In conclusion, OTA induces ferroptosis by inhibiting Sig-1R, subsequently promoting ferritinophagy, inhibiting GPX4/FSP1 antioxidant systems, reducing GSH levels, and ultimately increasing lipid peroxidation levels in vitro.

Membrane Receptor-Mediated Disruption of Cellular Homeostasis: Changes in Intracellular Signaling Pathways Increase the Toxicity of Ochratoxin A

Organisms maintain their cellular homeostatic balance by interacting with their environment through the use of their cell surface receptors. Membrane based receptors such as the transforming growth factor β receptor (TGFR), the prolactin receptor (PRLR), and hepatocyte growth factor receptor (HGFR), along with their associated signaling cascade, play significant roles in retaining cellular homeostasis. While these receptors and related signaling pathways are essential for health of cell and organism, their dysregulation can lead to imbalance in cell function with severe pathological conditions such as cell death or cancer. Ochratoxin A (OTA) can disrupt cellular homeostasis by altering expression levels of these receptors and/or receptor-associated intracellular downstream signaling modulators and/or pattern and levels of their phosphorylation/dephosphorylation. Recent studies have shown that the activity of the TGFR, the PRLR, and HGFR and their associated signaling cascades change upon OTA exposure. A critical evaluation of these findings suggests that while increased activity of the HGFR and TGFR signaling pathways leads to an increase in cell survival and fibrosis, decreased activity of the PRLR signaling pathway leads to tissue damage. This review explores the roles of these receptors in OTA-related pathologies and effects on cellular homeostasis.

Protopanaxadiol improves lupus nephritis by regulating the PTX3/MAPK/ERK1/2 pathway

Lupus nephritis (LN) is a kidney disease that occurs after systemic lupus erythematosus (SLE) affects the kidneys. Pentraxin 3 (PTX3) is highly expressed in the serum of patients with LN. Renal PTX3 deposition is directly related to clinical symptoms such as proteinuria and inflammation. The excessive proliferation of mesangial cells (MCs) is one of the representative pathological changes in the progression of LN, which is closely related to its pathogenesis. Protopanaxadiol (PPD) is the main component of ginsenoside metabolism and has not been reported in LN. The aim of this study was to investigate the relationship between PTX3 and mesangial cell proliferation and to evaluate the potential role and mechanism of PPD in improving LN. PTX3 is highly expressed in the kidneys of LN patients and LN mice and is positively correlated with renal pathological indicators, including proteinuria and PCNA. The excessive expression of PTX3 facilitated the proliferation of MCs, facilitated the activation of the MAPK/ERK1/2 signaling pathway, and increased the expression of HIF-1α. Further studies showed that PPD can effectively inhibit the abnormal proliferation of MCs with high expression of PTX3 and significantly improve LN symptoms such as proteinuria in MRL/lpr mice. The mechanism may be related to the inhibition of the PTX3/MAPK/ERK1/2 pathway. In this study, both in vitro, in vivo, and clinical sample results show that PTX3 is involved in the regulation of MCs proliferation and the early occurrence of LN. Natural active compound PPD can improve LN by regulating the PTX3/MAPK/ERK1/2 pathway.

Disruption of intestinal epithelial permeability in the Co-culture system of Caco-2/HT29-MTX cells exposed individually or simultaneously to acrylamide and ochratoxin A

Mycotoxins and thermal processing hazards are common contaminants in various foods and cause severe problems in terms of food safety and health. Combined use of acrylamide (AA) and ochratoxin A (OTA) would result in more significant intestinal toxicity than either toxin alone, but the underlying mechanisms behind this poor outcome remain unclear. Herein, we established the co-culture system of Caco-2/HT29-MTX cells for simulating a real intestinal environment that is more sensitive to AA and OTA, and showed that the combination of AA and OTA could up-regulate permeability of the intestine via increasing LY permeabilization, and decreasing TEER, then induce oxidative stress imbalance (GSH, SOD, MDA, and ROS) and inflammatory system disorder (TNF-α, IL-1β, IL-10, and IL-6), thereby leading a rapid decline in cell viability. Western blot, PAS- and AB-staining revealed that AA and OTA showed a synergistic effect on the intestine mainly through the disruption of tight junctions (TJs) and a mucus layer. Furthermore, based on correlation analysis, oxidative stress was more relevant to the mucus layer and TJs. Therefore, our findings provide a better evaluation model and a potential mechanism for further determining or preventing the combined toxicity caused by AA and OTA.

"Alphabet" Selenoproteins: Their Characteristics and Physiological Roles

Selenium (Se) is a metalloid that is recognized as one of the vital trace elements in our body and plays multiple biological roles, largely mediated by proteins containing selenium-selenoproteins. Selenoproteins mainly have oxidoreductase functions but are also involved in many different molecular signaling pathways, physiological roles, and complex pathogenic processes (including, for example, teratogenesis, neurodegenerative, immuno-inflammatory, and obesity development). All of the selenoproteins contain one selenocysteine (Sec) residue, with only one notable exception, the selenoprotein P (SELENOP), which has 10 Sec residues. Although these mechanisms have been studied intensely and in detail, the characteristics and functions of many selenoproteins remain unknown. This review is dedicated to the recent data describing the identity and the functions of several selenoproteins that are less known than glutathione peroxidases (Gpxs), iodothyronine deiodinases (DIO), thioredoxin reductases (TRxRs), and methionine sulfoxide reductases (Msrs) and which are named after alphabetical letters (i.e., F, H, I, K, M, N, O, P, R, S, T, V, W). These "alphabet" selenoproteins are involved in a wide range of physiological and pathogenetic processes such as antioxidant defense, anti-inflammation, anti-apoptosis, regulation of immune response, regulation of oxidative stress, endoplasmic reticulum (ER) stress, immune and inflammatory response, and toxin antagonism. In selenium deficiency, the "alphabet" selenoproteins are affected hierarchically, both with respect to the particular selenoprotein and the tissue of expression, as the brain or endocrine glands are hardly affected by Se deficiency due to their equipment with LRP2 or LRP8.

Lactoferrin alleviates cyclophosphamide induced-nephropathy through suppressing the orchestration between Wnt4/β-catenin and ERK1/2/NF-κB signaling and modulating klotho and Nrf2/HO-1 pathway

AIMS

Cyclophosphamide is an alkylating agent with vast arrays of therapeutic activity. Currently, its medical use is limited due to its numerous adverse events, including nephrotoxicity. This study aimed to follow the molecular mechanisms behind the potential renoprotective action of lactoferrin (LF) against cyclophosphamide (CP)-induced renal injury.

MATERIALS AND METHODS

For fulfillment of our aim, Spragw-Dwaly rats were orally administrated LF (300 mg/kg) for seven consecutive days, followed by a single intraperitoneal injection of CP (150 mg/kg).

KEY FINDINGS

Treatment of CP-injured rats with LF significantly reduced the elevated creatinine and blood urea nitrogen (BUN), markedly upregulated Nrf2/HO-1 signaling with consequent increase in renal total antioxidant capacity (TAC) and decrease in renal malondialdehyde (MDA) level. Furthermore, LF treatment significantly reduced the elevated renal p-ERK1/2 expression, tumor necrosis factor-α (TNFα), interleukin-6 (IL-6), nuclear factor-kappa B (NF-κB) levels in CP-treated animals. Interestingly, LF treatment downregulated Wnt4/β-catenin signaling and increased both renal klotho gene expression and serum klotho level. Furthermore, LF treatment reduced apoptosis in kidney tissue via suppressing GSK-3β expression and modulating caspase-3 and Bcl2 levels. Histopathological examination of kidney tissue confirmed the protective effect of LF against CP-induced renal injury.

SIGNIFICANCE

The present findings document the renoprotective effect of LF against CP-induced nephropathy, which may be mediated via suppressing ERK1/2/ NF-κB and Wnt4/β-catenin trajectories and enhancing klotho expression and Nrf2/HO-1 signaling.

Vascular peroxidase 1 promotes phenotypic transformation of pulmonary artery smooth muscle cells via ERK pathway in hypoxia-induced pulmonary hypertensive rats

AIMS

Vascular peroxidase 1 (VPO1) plays an important role in mediation of vascular remodeling with pulmonary arterial hypertension (PAH). This study aims to determine whether VPO1 can promote phenotypic transformation of pulmonary artery smooth muscle cells (PASMCs) and the underlying mechanisms.

MAIN METHODS

Sprague-Dawley (SD) rats were exposed to 10 % O₂ for 21 days to establish the model of vascular remodeling in pulmonary arterial hypertension. PASMCs were incubated with 3 % O₂ for 48 h to induce phenotypic transformation. Western blot was performed to detect the expressions of target proteins. The 5-ethynyl-2'-deoxyuridine (EdU) assay was conducted to measure the proliferation of PASMCs.

KEY FINDINGS

In the rats exposed to hypoxia, there were increases in right ventricular systolic pressure, pulmonary vascular remodeling and phenotypic transformation of PASMCs (the down-regulated contractile proteins of α-smooth muscle actin, smooth muscle 22α while the up-regulated synthetic proteins of osteopontin, cyclinD1), accompanied by up-regulation of VPO1, increase of hypochlorous acid (HOCl) production and elevation of the phosphorylation of ERK. In the cultured PASMCs exposed to hypoxia, similar results were achieved but they were reversed by VPO1 small interfering RNA (VPO1 siRNA) or HOCl inhibitor. Replacement of hypoxia with NaOCl could induce PASMCs phenotypic transformation and activate the ERK signaling. Furthermore, ERK inhibitor (PD98059) could also attenuate hypoxia-induced PASMCs phenotypic transformation.

SIGNIFICANCE

VPO1 play a pivotal role in promotion of phenotypic transformation of PASMCs under hypoxic condition through activation of VPO1/HOCl/ERK pathway. It might serve as a potential target for prevention of pulmonary vascular remodeling.

Protective and detoxifying effects conferred by selenium against mycotoxins and livestock viruses: A review

Animal feed can easily be infected with molds during production and storage processes, and this can lead to the production of secondary metabolites, such as mycotoxins, which eventually threaten human and animal health. Furthermore, livestock production is also not free from viral infections. Under these conditions, the essential trace element, selenium (Se), can confer various biological benefits to humans and animals, especially due to its anticancer, antiviral, and antioxidant properties, as well as its ability to regulate immune responses. This article reviews the latest literature on the antagonistic effects of Se on mycotoxin toxicity and viral infections in animals. We outlined the systemic toxicity of mycotoxins and the primary mechanisms of mycotoxin-induced toxicity in this analysis. In addition, we pay close attention to how mycotoxins and viral infections in livestock interact. The use of Se supplementation against mycotoxin-induced toxicity and cattle viral infection was the topic of our final discussion. The coronavirus disease 2019 (COVID-19) pandemic, which is currently causing a health catastrophe, has altered our perspective on health concerns to one that is more holistic and increasingly embraces the One Health Concept, which acknowledges the interdependence of humans, animals, and the environment. In light of this, we have made an effort to present a thorough and wide-ranging background on the protective functions of selenium in successfully reducing mycotoxin toxicity and livestock viral infection. It concluded that mycotoxins could be systemically harmful and pose a severe risk to human and animal health. On the contrary, animal mycotoxins and viral illnesses have a close connection. Last but not least, these findings show that the interaction between Se status and host response to mycotoxins and cattle virus infection is crucial.

Ochratoxin A-Induced Nephrotoxicity: Up-to-Date Evidence

Ochratoxin A (OTA) is a mycotoxin widely found in various foods and feeds that have a deleterious effect on humans and animals. It has been shown that OTA causes multiorgan toxicity, and the kidney is the main target of OTA among them. This present article aims to review recent and latest intracellular molecular interactions and signaling pathways of OTA-induced nephrotoxicity. Pyroptosis, lipotoxicity, organic anionic membrane transporter, autophagy, the ubiquitin-proteasome system, and histone acetyltransferase have been involved in the renal toxicity caused by OTA. Meanwhile, the literature reviewed the alternative or method against OTA toxicity by reducing ROS production, oxidative stress, activating the Nrf2 pathway, through using nanoparticles, a natural flavonoid, and metal supplement. The present review discloses the molecular mechanism of OTA-induced nephrotoxicity, providing opinions and strategies against OTA toxicity.

Selective Activation of Endoplasmic Reticulum Stress by Reactive-Oxygen-Species-Mediated Ochratoxin A-Induced Apoptosis in Tubular Epithelial Cells

Ochratoxin A (OTA), one of the major food-borne mycotoxins, impacts the health of humans and livestock by contaminating food and feed. However, the underlying mechanism of OTA nephrotoxicity remains unknown. This study demonstrated that OTA induced apoptosis through selective endoplasmic reticulum (ER) stress activation in human renal proximal tubular cells (HK-2). OTA increased ER-stress-related JNK and precursor caspase-4 cleavage apoptotic pathways. Further study revealed that OTA increased reactive oxygen species (ROS) levels, and N-acetyl cysteine (NAC) could reduce OTA-induced JNK-related apoptosis and ROS levels in HK-2 cells. Our results demonstrate that OTA induced ER stress-related apoptosis through an ROS-mediated pathway. This study provides new evidence to clarify the mechanism of OTA-induced nephrotoxicity.