Ochratoxin a induces hepatic fibrosis through TGF-β receptor I/Smad2/3 signaling pathway

Integration analysis of miRNA-mRNA uncovers the mechanisms of ochratoxin A-induced hepatotoxicity

Ochratoxin A (OTA), the most toxic member of the ochratoxin family, is frequently detected in contaminated food and beverages, posing substantial health risks to both humans and animals, particularly due to its hepatotoxic effects. Although OTA is known to cause liver damage, the precise molecular mechanisms driving its toxicity remain poorly understood. In this study, we explored the hepatotoxic effects of OTA using LO2 cells and zebrafish models, combining miRNA and mRNA analyses to uncover the underlying mechanisms. Our results demonstrated that OTA significantly suppressed cell proliferation and viability, induced cell cycle arrest, triggered apoptosis and elevated reactive oxygen species (ROS) production in LO2 cells, with analogous apoptotic effects observed in zebrafish larvae. Additionally, miRNA-mRNA analysis revealed that differentially expressed genes (DEGs) and miRNAs (DEMs) were significantly enriched in pathways related to apoptosis, cell cycle regulation, and MAPK signaling. We constructed a potential regulatory network, identifying three key miRNAs (hsa-miR-3065-5p, hsa-miR-520g-3p, and hsa-miR-5698) and three associated hub mRNAs (CACNA1D, CDC6, and E2F1). Moreover, OTA treatment specifically induced p38 phosphorylation without significantly altering the phosphorylation levels of ERK or JNK. Collectively, this study established a comprehensive framework for understanding the hepatotoxic mechanisms of OTA at the miRNA and mRNA levels, providing critical insights into the pathogenesis of hepatotoxicity induced by ochratoxins and contributing to the prevention and management of related diseases.

Progress of Pyruvate Kinase M2 in Hepatocellular Carcinoma-Associated Signaling Pathway

Hepatocellular carcinoma (HCC) is an aggressive liver tumor with a unique metabolic profile and a shift to glycolytic metabolism. This review discusses the contribution of pyruvate kinase M2 (PKM2) to HCC development and its potential as a target for therapy. We carried out a broad literature review on PKM2, focusing on its role in the glycolytic pathway and special interactions with key signaling pathways like Phosphoinositide 3-kinase/Protein kinase B/Mammalian target of rapamycin (PI3K/AKT/mTOR) and Mitogen-activated protein kinase (MAPK). PKM2 also performs a dual role in energy metabolism and signal transduction in HCC. PKM2 is paramount in the induction of HCC by regulating cellular metabolism and oncogenic signaling pathways. It promotes tumor growth, survival, and metastasis through interaction with the PI3K/AKT/mTOR and MAPK pathways. PKM2 is a key factor in HCC pathogenesis, with a dual impact on metabolism and signaling. Its properties may open the way for developing novel therapeutic interventions against HCC. Thus, PKM2 inhibition may offer further opportunities for tumor growth blockade, which could meaningfully improve patients' clinical outcomes.

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.

New perspective on mechanism in muscle toxicity of ochratoxin A: Model of juvenile grass carp (Ctenopharyngodon idella)

Ochratoxin A (OTA) is a common fungal toxin that pollutes raw materials of aquatic feeds (such as corn, soybean meal, and wheat). This study explored the effects of OTA through diet on muscle toxicity in juvenile grass carp (Ctenopharyngodon idella). The following results were obtained for the muscle. (1) With an increase in dietary OTA, the residue of OTA in muscle increased, muscle fiber diameter and density decreased, and even muscle fiber breakage. (2) OTA caused oxidative stress by downregulating GPx1 (a, b) and Trx via inhibited the PGC1-α/Nrf2 signaling pathway. (3) OTA exacerbated endoplasmic reticulum stress in the muscle by causing endoplasmic reticulum expansion (results of transmission electron microscopy) and upregulating the expression of GRP78, eIF2α, ATF6, PERK, and CHOP. (4) OTA reduced muscle fiber diameter by inhibiting protein synthesis (AKT, TOR, and S6K1) and promoting the mRNA expression of protein degradation-related genes (MURF1, MAFBX, and FoxO3a), as well as by reducing AKT and promoting the immunofluorescence expression of FoxO3. (5) OTA inhibits collagen deposition by downregulating TGF-β1, TGF-βR1, Smad2, Smad3, Smad4, CTGF, TIMP, PHD, and LOX mRNA expressions as well as the CTGF immunofluorescence expression. Moreover, based on the GSH and collagen content contents, the upper safe dose for OTA-induced toxicity was 963.6 and 1129.6 μg/kg diet, respectively. Using the example of OTA, our research has provided new insights that raise concerns about the quality of aquatic products by exploring muscle toxicity caused by mycotoxins.

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.

Exosome-derived miR-142-5p from liver stem cells improves the progression of liver fibrosis by regulating macrophage polarization through CTSB

BACKGROUND

This study aims to explore the effect of liver stem cells (LSCs)-derived exosomes and the miR-142a-5p carried by them on the process of fibrosis by regulating macrophages polarization.

METHODS

In this study, CCL₄ was used to establish liver fibrosis model. The morphology and purity of exosomes (EVs) were verified by transmission electron microscopy, western blotting (WB) and nanoparticle tracing analysis (NTA). Real-time quantitative PCR (qRT-PCR), WB and enzyme-linked immunoadsorption (ELISA) were used to detect liver fibrosis markers, macrophage polarization markers and liver injury markers. Histopathological assays were used to verify the liver injury morphology in different groups. The cell co-culture model and liver fibrosis model were constructed to verify the expression of miR-142a-5p and ctsb.

RESULTS

Immunofluorescence of LSCs markers CK-18, epithelial cell adhesion molecule (EpCam), and AFP showed that these markers were up-regulated in LSCs. In addition, we evaluated the ability of LSCs to excrete EVs by labeling LSCs-EVs with PKH67. We found that CCL₄ and EVs were simultaneously treated at 50 and 100 μg doses, and both doses of EVs could reduce the degree of liver fibrosis in mice. We tested markers of M1 or M2 macrophage polarization and found that EVs reduced M1 marker expression and promoted M2 marker expression. Further, ELISA was used to detect the secreted factors related to M1 and M2 in tissue lysates, which also verified the above views. Further analysis showed that the expression of miR-142a-5p increased significantly with the increase of EVs treatment concentration and time. Further, in vitro and in vivo LSCs-EVs regulate macrophage polarization through miR-142a-5p/ctsb pathway and affect the process of liver fibrosis.

CONCLUSION

Our data suggest that EVs-derived miR-142-5p from LSCs improves the progression of liver fibrosis by regulating macrophage polarization through ctsb.

Fluorescent Sensor Based on Magnetic Separation and Strand Displacement Amplification for the Sensitive Detection of Ochratoxin A

Ochratoxin A (OTA) is a common mycotoxin, and it is a significant threat to human health throughout the food chain. In this study, a sensitive and specific fluorescent sensor based on magnetic separation technology combined with chain displacement amplification was developed for fast and easy detection of OTA in food. The designed strand displacement amplification can improve the sensitivity for the detection, and the magnetic nanomaterials can provide a large surface area, thus enhancing the capture efficiency of the target from the sample. Based on those designs, the experimental results showed that the proposed method displayed excellent performance. The linearity range was 0.5-128.0 ng/mL. The detection limit was 0.125 ng/mL; the relative standard deviations were 3.92-7.71%. Additionally, the developed method was satisfactorily applied to determine OTA in wheat, corn, and red wine samples at three spiked levels (1.0, 8.0, and 64.0 ng/mL). The recoveries ranged from 85.45 to 107.8% for wheat flour, 101.34 to 108.35% for corn flour, and 91.15 to 93.80% for red wine, respectively. Compared with high-performance liquid chromatography, the proposed method showed a lower limit of detection and equal recovery. Hence, the designed method is a potential and good detecting tool for OTA residue analysis in complex matrix samples.

Autophagy affects hepatic fibrosis progression by regulating macrophage polarization and exosome secretion

BACKGROUND

In this study, the role of autophagy in hepatic fibrosis and its effects on macrophage polarization and exosomes (EVs) were verified by establishing hepatic fibrosis model and co-culture model, providing evidence for treatment.

METHODS

In this study, CCL₄ was used to establish hepatic fibrosis model. The morphology and purity of exosomes (EVs) were verified by transmission electron microscopy, western blotting (WB), and nanoparticle tracing analysis (NTA). Real-time quantitative PCR (qRT-PCR), WB and enzyme-linked immunoadsorption (ELISA) were used to detect hepatic fibrosis markers, macrophage polarization markers and liver injury markers. Histopathological assays were used to verify the liver injury morphology in different groups. The cell co-culture model and hepatic fibrosis model were constructed to verify the expression of miR-423-5p.

RESULTS

Hepatic fibrosis model showed that CCL₄ promoted early autophagy increase but inhibited autophagy flux in liver. mRFP-GFP-LC3 detection showed that both LPS group and Baf group inhibited autophagy flux. This inhibitory effect was reversed by Rap combination therapy. The M1/M2 markers of macrophage polarization were further tested, and it was found that LPS and Baf could promote M1 polarization and inhibit M2 polarization. Rap processing reverses this phenomenon. These data suggest that autophagy can regulate the polarization process of liver macrophages. WB and NTA showed that LPS induced EVs generation. In addition, LPS-induced EVs could promote HSC proliferation, cell cycle, migration, and the expression of fibrosis markers. Macrophage-EVs could affect the fibrosis process of stellate cells through the secretion of miR-423a-5p expression. The hepatic fibrosis model was further established to verify the regulation of autophagy and EVs on the fibrosis process.

CONCLUSION

This study was showed that autophagy could regulate fibrosis by promoting HSC activation by regulating macrophage polarization and exosome secretion.

Mycotoxins: Emerging toxic mechanisms, and unanswered research questions

Recently, a series of toxic mechanisms have been explored in mycotoxins. Emerging evidence show that mycotoxins may induce human neurodegenerative diseases (ND); however, this idea is still unproven. Besides to identify this hypothesis, some questions, for example, how the mycotoxins induce this disease and what the molecular mechanism is, as well as whether the brain-gut axis is involved in this context, should be answered. Very recent studies further reported an "immune evasion" mechanism in trichothecenes; moreover, hypoxia seems to play important function in this process; nevertheless, whether this "immune evasion" process is present in other mycotoxins, especially in aflatoxins, should be tested. In this work, we mainly discussed some key scientific questions that need to be answered in the toxic mechanisms of mycotoxins. We especially focused on the research questions in the key signaling pathways, balance mechanism of immunostimulatory and immunosuppressive effects, and the relationship between autophagy and apoptosis. Interesting topics such as mycotoxins and aging, cytoskeleton and immunotoxicity are also discussed. More importantly, we compile a special issue: "New insight into mycotoxins and bacterial toxins: toxicity assessment, molecular mechanism and food safety" for Food and Chemical Toxicology. Researchers are encouraged to submit their newest work to this special issue.

Xiaotangzhike Pill Attenuates the Progression of Diabetes In Vivo through the Mediation of the Akt/GSK-3β Axis

Background

Diabetes seriously threatens the health of people. Traditional Chinese medicine has been proven to inhibit the progression of diabetes. Meanwhile, the Xiaotangzhike pill (XTZK) was known to alleviate the symptom of diabetes. Thus, this research decided to investigate the mechanism underlying the impact of XTZK in diabetes remains unexplored.

Methods

To assess the impact of XTZK in diabetes, in vivo model of diabetes was constructed. The contents of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), triglyceride (TG), and high-density lipoprotein cholesterol (HDL-C) in the rats were tested by the commercial kits. In addition, Masson and hematoxylin and eosin (H&E) staining were applied for assessing the histological changes and fibrosis in the rats, respectively. Furthermore, a western blot was applied to assess the protein levels.

Results

Streptozotocin (STZ) significantly increased the levels of area under the curve (AUC), TG, TC, LDL-C, and decreased the contents of HDL-C in rats, while these phenomena were partially reversed by XTZK. In addition, STZ notably induced inflammatory infiltration and fibrosis in the liver tissues of rats, which was greatly restored by XTZK. The levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and malondialdehyde (MDA) in the serum of rats were notably upregulated by STZ, while the effect of STZ was markedly abolished by XTZK. Meanwhile, STZ-caused the upregulation of p-Smad2 and α-SMA in rats was restored by XTZK. Furthermore, XTZK notably inhibited the progression of Qi and Yin deficiency syndrome in diabetes through the mediation of the Akt/GSK-3β axis.

Conclusion

The Xiaotangzhike pill attenuates the progression of diabetes through the mediation of the Akt/GSK-3β axis. Hence, our study might supply a novel insight into discovering new strategies against diabetes.