Trichothecene mycotoxin deoxynivalenol (DON) negatively regulates immune response by damaging host immune system and harming the organism's health. We hypothesized that DON can initiate an active immunosuppressive mechanism similar to "immune evasion" to alter the cellular microenvironment and evade immune surveillance. We tested this hypothesis using the RAW264.7 macrophage model. DON rapidly increased the expression of immune checkpoints PD-1 and PD-L1, inflammatory cytokine TGF-β, and key immune evasion factors STAT3, VEGF, and TLR-4, and caused cellular hypoxia. Importantly, hypoxia-inducible factor-1α (HIF-1α) acts as a key regulator of DON-induced immunosuppression. HIF-1α accumulated in the cytoplasm and was gradually transferred to the nucleus following DON treatment. Moreover, DON activated HIF-1α through STAT3 signaling to upregulate downstream signaling, including PD-1/PD-L1. Under DON treatment, immunosuppressive miR-210-3p, lncRNA PVT1, lncRNA H19, and lncRNA HOTAIR were upregulated by the STAT3/HIF-1α axis. Moreover, DON damaged mitochondrial function, causing mitophagy, and suppressed immune defenses. Collectively, DON triggered RAW264.7 intracellular hypoxia and rapidly activated HIF-1α via STAT3 signaling, activating immune evasion signals, miRNAs, and lncRNAs, thereby initiating the key link of immune evasion. This study offers further clues for accurate prevention and treatment of immune diseases caused by mycotoxins.
Days ago, the Nobel Prize in Physiology or Medicine 2018 was awarded jointly to James P. Allison and Tasuku Honjo "for their discovery of cancer therapy by inhibition of negative immune regulation". This news has increased the attention on immunotoxicity and immune evasion mechanisms, which are once again hot research topics. Actually, increasing lines of evidence show that trichothecene mycotoxins have a strong immunosuppressive effect. These mycotoxins suppress the host immunity and make them more sensitive to the infection of pathogens, including bacteria and viruses. However, the underlying mechanism(s) in this context is still poorly understood. Interestingly, recent work showed that an immune evasion mechanism might be involved in trichothecene immunotoxicity. In this work, we discuss the potential immune evasion mechanism in trichothecene immunotoxicity. More importantly, under these circumstances, we are pleased to compile a Special Issue entitled "Biochemistry, Molecular Biology, and Toxicology of Natural and Synthetic Toxins" for the International Journal of Molecular Sciences (IJMS). Researchers are encouraged to share their latest interesting findings with the readers of IJMS.
- MeSH
- imunitní únik * MeSH
- imunosupresiva farmakologie terapeutické užití MeSH
- lidé MeSH
- trichotheceny farmakologie terapeutické užití MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- úvodní články MeSH
- úvodníky MeSH
Cyclosporine A (CsA) is a widely used immunosuppressive agent that greatly reduces the rates of kidney-, heart-, and liver-transplant rejection. However, CsA nephrotoxicity is a serious side effect that limits the clinical use of CsA. While the mechanisms underlying CsA nephrotoxicity are still not fully understood, increasing lines of evidence suggest that oxidative stress plays an important role in this phenomenon. Specifically, CsA induces endoplasmic reticulum stress and increases mitochondrial reactive oxygen species production: this modifies the redox balance, which causes lipid peroxidation and thereby induces nephrotoxicity. Recent studies on the pathogenesis of CsA nephrotoxicity suggest that CsA-induced autophagy can alleviate the deleterious effects of CsA-induced endoplasmic reticulum stress, thereby preventing nephrotoxicant-induced renal injury. A variety of signaling pathways participate in the pathogenesis of CsA nephrotoxicity. Specifically, the p38, ERK, and JNK MAPK subfamilies are all involved in CsA nephrotoxicity, while NF-κB is a target molecule of CsA. Moreover, the fibrogenic cytokine TGF-β1 contributes to CsA-induced renal fibrosis, while Nrf2 modulates CsA-induced cellular oxidative stress. In addition, CsA generally inhibits nitric oxide synthesis and impairs endothelium-dependent relaxation in the renal artery. However, some reports also suggest that nitric oxide synthesis is enhanced in the kidney cortex during CsA nephrotoxicity. Notably, the biomarkers of CsA nephrotoxicity associated with CsA have not been reviewed previously. Therefore, in this review, we will first provide an update on CsA nephrotoxicity in humans and describe the potential biomarkers of CsA nephrotoxicity. The molecular and cellular mechanisms that underlie CsA nephrotoxicity and the roles played by oxidative stress, autophagy, and signaling pathways will then be comprehensively summarized and discussed. Finally, the current therapeutical strategies for CsA nephrotoxcixity are summarized. We hope this review will provide a better understanding of CsA nephrotoxicity, thereby improving the management of patients who are treated with CsA.
- MeSH
- autofagie účinky léků MeSH
- cyklosporin toxicita MeSH
- imunosupresiva toxicita MeSH
- ledviny účinky léků MeSH
- lidé MeSH
- oxidační stres účinky léků MeSH
- signální transdukce účinky léků MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Trichothecenes are a group of mycotoxins mainly produced by fungi of genusFusarium. Due to high toxicity and widespread dissemination, T-2 toxin and deoxynivalenol (DON) are considered to be the most important compounds of this class. Trichothecenes generate free radicals, including reactive oxygen species (ROS), which induce lipid peroxidation, decrease levels of antioxidant enzymes, and ultimately lead to apoptosis. Consequently, oxidative stress is an active area of research on the toxic mechanisms of trichothecenes, and identification of antioxidant agents that could be used against trichothecenes is crucial for human health. Numerous natural compounds have been analyzed and have shown to function very effectively as antioxidants against trichothecenes. In this review, we summarize the molecular mechanisms underlying oxidative stress induced by these compounds, and discuss current knowledge regarding such antioxidant agents as vitamins, quercetin, selenium, glucomannan, nucleotides, antimicrobial peptides, bacteria, polyunsaturated fatty acids, oligosaccharides, and plant extracts. These products inhibit trichothecene-induced oxidative stress by (1) inhibiting ROS generation and induced DNA damage and lipid peroxidation; (2) increasing antioxidant enzyme activity; (3) blocking the MAPK and NF-κB signaling pathways; (4) inhibiting caspase activity and apoptosis; (5) protecting mitochondria; and (6) regulating anti-inflammatory actions. Finally, we summarize some decontamination methods, including bacterial and yeast biotransformation and degradation, as well as mycotoxin-binding agents. This review provides a comprehensive overview of antioxidant agents against trichothecenes and casts new light on the attenuation of oxidative stress.
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Paradoxically, trichothecenes have both immunosuppressive and immunostimulatory effects. The underlying mechanisms have not been fully explored. Early studies show that dose, exposure timing, and the time at which immune function is assessed influence whether trichothecenes act in an immunosuppressive or immunostimulatory fashion. Recent studies suggest that the immunomodulatory function of trichothecenes is also actively shaped by competing cell-survival and death-signaling pathways. Autophagy may also promote trichothecene immunosuppression, although the mechanism may be complicated. Moreover, trichothecenes may generate an "immune evasion" milieu that allows pathogens to escape host and vaccine immune defenses. Some trichothecenes, especially macrocyclic trichothecenes, also potently kill cancer cells. T-2 toxin conjugated with anti-cancer monoclonal antibodies significantly suppresses the growth of thymoma EL-4 cells and colon cancer cells. The type B trichothecene diacetoxyscirpenol specifically inhibits the tumor-promoting factor HIF-1 in cancer cells under hypoxic conditions. Trichothecin markedly inhibits the growth of multiple cancer cells with constitutively activated NF-κB. The type D macrocyclic toxin Verrucarin A is also a promising therapeutic candidate for leukemia, breast cancer, prostate cancer, and pancreatic cancer. The anti-cancer activities of trichothecenes have not been comprehensively summarized. Here, we first summarize the data on the immunomodulatory effects of trichothecenes and discuss recent studies that shed light on the underlying cellular and molecular mechanisms. These mechanisms include autophagy and major signaling pathways and their crosstalk. Second, the anti-cancer potential of trichothecenes and the underlying mechanisms will be discussed. We hope that this review will show how trichothecene bioactivities can be exploited to generate therapies against pathogens and cancer.
- MeSH
- antikarcinogenní látky farmakologie MeSH
- autofagie účinky léků imunologie MeSH
- imunoglobulin A imunologie MeSH
- imunologické faktory farmakologie MeSH
- imunosupresiva farmakologie MeSH
- infekce farmakoterapie imunologie MeSH
- lidé MeSH
- signální transdukce účinky léků imunologie MeSH
- trichotheceny chemie farmakologie MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
