Excessive ER-phagy contributes to ochratoxin A-induced apoptosis

DDRGK1-mediated ER-phagy attenuates acute kidney injury through ER-stress and apoptosis

Acute kidney injury (AKI) constitutes a prevalent clinical syndrome characterized by elevated morbidity and mortality rates, emerging as a significant public health issue. This study investigates the interplay between endoplasmic reticulum (ER) stress, unfolded protein response (UPR), and ER-associated degradation (ER-phagy) in the pathogenesis of AKI. We employed four distinct murine models of AKI-induced by contrast media, ischemia-reperfusion injury, cisplatin, and folic acid-to elucidate the relationship between ER-phagy, ER stress, and apoptosis. Our findings reveal a marked decrease in ER-phagy coinciding with an accumulation of damaged ER, elevated ER stress, and increased apoptosis across all AKI models. Importantly, overexpression of DDRGK1 in HK-2 cells enhanced ER-phagy levels, ameliorating contrast-induced ER stress and apoptosis. These findings unveil a novel protective mechanism in AKI, wherein DDRGK1-UFL1-mediated ER-phagy mitigates ER stress and apoptosis in renal tubular epithelial cells. Our results thereby contribute to understanding the molecular underpinnings of AKI and offer potential therapeutic targets for its treatment.

Sinapic Acid Attenuates Chronic DSS-Induced Intestinal Fibrosis in C57BL/6J Mice by Modulating NLRP3 Inflammasome Activation and the Autophagy Pathway

Ulcerative colitis (UC) is a chronic gastrointestinal disease that results from repeated inflammation and serious complications. Sinapic acid (SA) is a hydroxycinnamic acid present in a variety of plants that has antioxidant, anti-inflammatory, anticancer, and other protective effects. This study investigated the antifibrotic effect of SA on chronic colitis induced by dextran sulfate sodium salt (DSS) in mice. We observed that SA could significantly reduce clinical symptoms (such as improved body weight loss, increased colon length, and decreased disease activity index score) and pathological changes in mice with chronic colitis. SA supplementation has been demonstrated to repair intestinal mucosal barrier function and maintain epithelial homeostasis by inhibiting activation of the NLRP3 inflammasome and decreasing the expression of IL-6, TNF-α, IL-17A, IL-18, and IL-1β. Furthermore, SA could induce the expression of antioxidant enzymes (Cat, Sod1, Sod2, Mgst1) by activating the Nrf2/keap1 pathway, thus improving antioxidant capacity. Additionally, SA could increase the protein expression of downstream LC3-II/LC3-I and Beclin1 and induce autophagy by regulating the AMPK-Akt/mTOR signaling pathway, thereby reducing the production of intestinal fibrosis-associated proteins Collagen-I and α-SMA. These findings suggest that SA can enhance intestinal antioxidant enzymes, reduce oxidative stress, expedite intestinal epithelial repair, and promote autophagy, thereby ameliorating DSS-induced colitis and intestinal fibrosis.

Combined exposure to deoxynivalenol facilitates lipid metabolism disorder in high-fat-diet-induced obesity mice

Deoxynivalenol (DON) is a trichothecene toxin that mainly produced by strains of Fusarium spp. DON contamination is widely distributed and is a global food safety threat. Existing studies have expounded its harmful effects on growth inhibition, endocrine disruption, immune function impairment, and reproductive toxicity. In energy metabolism, DON suppresses appetite, reduces body weight, triggers lipid oxidation, and negatively affects cholesterol and fatty acid homeostasis. In this study, high-fat diet (HFD) induced obese C57BL/6J mice were orally treated with 0.1 mg/kg bw/d and 1.0 mg/kg bw/d DON for 4 weeks. The lipid metabolism of mice and the molecular mechanisms were explored. The data showed that although DON reduced body weight and fat mass in HFD mice, it significantly increased their serum triglyceride concentrations, disturbance of serum lipid metabolites, impaired glucose, and resulted in insulin intolerance in mice. In addition, the transcriptional and expression changes of lipid metabolism genes in the liver and epididymis (EP) adipose indicate that the DON-mediated increase in serum triglycerides is caused by lipoprotein lipase (LPL) inhibition in EP adipose. Furthermore, DON down-regulates the expression of LPL through the PPARγ signaling pathway in EP adipose. These results are further confirmed by the serum lipidomics analysis. In conclusion, DON acts on the PPARγ pathway of white adipose to inhibit the expression of LPL, mediate the increase of serum triglyceride in obese mice, disturb the homeostasis of lipid metabolism, and increase the risk of cardiovascular disease. This study reveals the interference mechanism of DON on lipid metabolism in obese mice and provides a theoretical basis for its toxic effect in obese individuals.

Simulating ozone degradation of deoxynivalenol and its bio-safety assessment by mouse model

Deoxynivalenol (DON), a trichothecene mycotoxin, is one of the most prevalent mycotoxins globally, primarily produced by Fusarium species. DON exposure could cause a range of symptoms, including nausea, vomiting, gastroenteritis, growth retardation, immunosuppression, and intestinal flora disorders in both humans and animals. Recently, ozone degradation technology has been applied for DON control. However, the safety of the contaminated grain after degradation was often ignored. Therefore, the implementation technology for assessing the safety of DON-contaminated grain degradation is of great significance for food safety. In this study, based on previous degradation result of DON, we further studied and assessed the toxicity of corn contaminated with ozone-degrading DON by animal experiments in mice. We simulated feed made from corn contaminated with DON produced by inoculated Fusarium graminearum, which was treated with an ozone aqueous solution. DON treated by ozone could effectively increase the expression of total protein in mice and improve the immune system efficacy. Meanwhile, compared with DON directly-exposed mice, the corn with degrading DON could effectively maintain the level of liver and kidney immune function, and improved growth performance, enterohepatic circulation, and energy metabolism. Our study indicated that the toxicity of fed corn contaminated with degrading-DON decreased significantly after ozone degradation, resulting in a much lower toxicity compared to the DON group, or nontoxicity to some extent. Therefore, we hope that this mouse model could be used as a promising approach for assessing the risk of fungal toxins on metabolism, immunity, and intestinal health.

The Effect of Mycotoxins and Their Mixtures on Bovine Spermatozoa Characteristics

There is growing concern about the effects of mycotoxins on mammalian reproduction. Although the effects of single mycotoxins have been well documented, the impact of their mixtures on spermatozoon quality is less known. Here, frozen-thawed semen (n = 6 bulls) was in-vitro-cultured (2 h) without (control) or with (i) a single mycotoxin [zearalenone (ZEN), ochratoxin A (OTA), toxin 2 (T2), and diacetoxyscirpenol (DAS)] in a dose-response manner; (ii) binary mixtures (OTA + T2, OTA + ZEN, OTA + DAS, ZEN + T2, DAS + T2 and ZEN + DAS); or (iii) ternary mixtures (OTA + DAS + T2, OTA + ZEN + T2, and ZEN + DAS + T2). Then, the spermatozoa quality was characterized according to its plasma- and acrosome-membrane integrity, mitochondrial membrane potential, and oxidation status by a flow cytometer. Exposure to single mycotoxins or binary mixtures did not affect the spermatozoa characteristics. However, exposure to the ternary mixtures, OTA + DAS + T2 and OTA + ZEN + T2, reduced (p < 0.05) the mitochondrial membrane potential relative to the control. In addition, OTA + ZEN + T2 increased (p < 0.05) the proportion of spermatozoa with reactive oxygen species relative to the control. The most suggested interaction effect between the mycotoxins was found to be an additive one. A synergistic interaction, mainly regarding the oxidation status of the spermatozoa, was also found between the mycotoxins. The current study sheds light on the potential risk of exposing spermatozoa to a mycotoxin mixture.

MiR-155-5p Elevated by Ochratoxin A Induces Intestinal Fibrosis and Epithelial-to-Mesenchymal Transition through TGF-β Regulated Signaling Pathway In Vitro and In Vivo

Ochratoxin A (OTA) is a mycotoxin that induces fibrosis and epithelial-to-mesenchymal transitions (EMT) in kidneys and livers. It enters our bodies through food consumption, where it is absorbed in the intestines. However, the impact of OTA on the intestines is yet to be studied. MicroRNA (miRNAs) are small non-coding single-stranded RNAs that block the transcription of specific mRNAs and are, therefore, involved in many biochemical processes. Our findings indicate that OTA can induce EMT and intestinal fibrosis both in vivo and in vitro. This study examines the impact of OTA on intestinal toxicity and the role of miRNAs in this process. Following OTA treatment, miR-155-5p was the most elevated miRNA by next-generation sequencing. Our research showed that OTA increased miR-155-5p levels through transforming growth factor β (TGF-β), leading to the development of intestinal fibrosis and EMT. Additionally, the study identified that the modulation of TGF-β and miR-155-5p by OTA is linked to the inhibition of CCAAT/enhancer-binding protein β (C/EBPβ) and Smad2/3 accumulation in the progression of intestinal fibrosis.