Autophagy protects PC12 cells against deoxynivalenol toxicity via the Class III PI3K/beclin 1/Bcl-2 pathway

Neurotoxic mechanisms of mycotoxins: Focus on aflatoxin B1 and T-2 toxin

Aflatoxin B1 (AFB1) and T-2 toxin are commonly found in animal feed and stored grain, posing a serious threat to human and animal health. Mycotoxins can penetrate brain tissue by compromising the blood-brain barrier, triggering oxidative stress and neuroinflammation, and leading to oxidative damage and apoptosis of brain cells. The potential neurotoxic mechanisms of AFB1 and T-2 toxin were discussed by summarizing the relevant research reports from the past ten years. AFB1 and T-2 toxin cause neuronal damage in the cerebral cortex and hippocampus, leading to synaptic transmission dysfunction, ultimately impairing the nervous system function of the body. The toxic mechanism is related to excessive reactive oxygen species (ROS), oxidative stress, mitochondrial dysfunction, apoptosis, autophagy, and an exaggerated inflammatory response. After passing through the blood-brain barrier, toxins can directly affect glial cells, alter the activation state of microglia and astrocytes, thereby promoting brain inflammation, disrupting the blood-brain barrier, and influencing the synaptic transmission process. We discussed the diverse effects of various concentrations of toxins and different modes of exposure on neurotoxicity. In addition, toxins can also cross the placental barrier, causing neurotoxic symptoms in offspring, as demonstrated in various species. Our goal is to uncover the underlying mechanisms of the neurotoxicity of AFB1 and T-2 toxin and to provide insights for future research, including investigating the impact of mycotoxins on interactions between microglia and astrocytes.

P7C3-A20 treats traumatic brain injury in rats by inhibiting excessive autophagy and apoptosis

Traumatic brain injury is a severe health problem leading to autophagy and apoptosis in the brain. 3,6-Dibromo-beta-fluoro-N-(3-methoxyphenyl)-9H-carbazole-9-propanamine (P7C3-A20) can be neuroprotective in various diseases, including ischemic stroke and neurodegenerative diseases. However, whether P7C3-A20 has a therapeutic effect on traumatic brain injury and its possible molecular mechanisms are unclear. Therefore, in the present study, we investigated the therapeutic effects of P7C3-A20 on traumatic brain injury and explored the putative underlying molecular mechanisms. We established a traumatic brain injury rat model using a modified weight drop method. P7C3-A20 or vehicle was injected intraperitoneally after traumatic brain injury. Severe neurological deficits were found in rats after traumatic brain injury, with deterioration in balance, walking function, and learning memory. Furthermore, hematoxylin and eosin staining showed significant neuronal cell damage, while terminal deoxynucleotidyl transferase mediated dUTP nick end labeling staining indicated a high rate of apoptosis. The presence of autolysosomes was observed using transmission electron microscope. P7C3-A20 treatment reversed these pathological features. Western blotting showed that P7C3-A20 treatment reduced microtubule-associated protein 1 light chain 3-II (LC3-II) autophagy protein, apoptosis-related proteins (namely, Bcl-2/adenovirus E1B 19-kDa-interacting protein 3 [BNIP3], and Bcl-2 associated x protein [Bax]), and elevated ubiquitin-binding protein p62 (p62) autophagy protein expression. Thus, P7C3-A20 can treat traumatic brain injury in rats by inhibiting excessive autophagy and apoptosis.

Autophagy modulation changes mechano-chemical sensitivity of T24 bladder cancer cells

Bladder cancer cells possess unique adaptive capabilities: shaped by their environment, cells face a complex chemical mixture of metabolites and xenobiotics accompanied by physiological mechanical cues. These responses might translate into resistance to chemotherapeutical regimens and can largely rely on autophagy. Considering molecules capable of rewiring tumor plasticity, compounds of natural origin promise to offer valuable options. Fungal derived metabolites, such as bafilomycin and wortmannin are widely acknowledged as autophagy inhibitors. Here, their potential to tune bladder cancer cells´ adaptability to chemical and physical stimuli was assessed. Additionally, dietary occurring mycotoxins were also investigated, namely deoxynivalenol (DON, 0.1-10 µM) and fusaric acid (FA, 0.1-1 mM). Endowing a Janus' face behavior, DON and FA are on the one side described as toxins with detrimental health effects. Concomitantly, they are also explored experimentally for selective pharmacological applications including anticancer activities. In non-cytotoxic concentrations, bafilomycin (BAFI, 1-10 nM) and wortmannin (WORT, 1 µM) modified cell morphology and reduced cancer cell migration. Application of shear stress and inhibition of mechano-gated PIEZO channels reduced cellular sensitivity to BAFI treatment (1 nM). Similarly, for FA (0.5 mM) PIEZO1 expression and inhibition largely aligned with the modulatory potential on cancer cells motility. Additionally, this study highlighted that the activity profile of compounds with similar cytotoxic potential (e.g. co-incubation DON with BAFI or FA with WORT) can diverge substantially in the regulation of cell mechanotransduction. Considering the interdependence between tumor progression and response to mechanical cues, these data promise to provide a novel viewpoint for the study of chemoresistance and associated pathways.

Combination of Zearalenone and Deoxynivalenol Induces Apoptosis by Mitochondrial Pathway in Piglet Sertoli Cells: Role of Endoplasmic Reticulum Stress

Zearalenone (ZEA) and deoxynivalenol (DON) are widely found in various feeds, which harms livestock's reproductive health. Both mitochondria and endoplasmic reticulum (ER) can regulate cell apoptosis. This study aimed to explore the regulatory mechanism of endoplasmic reticulum stress (ERS) on ZEA- combined with DON-induced mitochondrial pathway apoptosis in piglet Sertoli cells (SCs). The results showed that ZEA + DON damaged the ultrastructure of the cells, induced apoptosis, decreased mitochondrial membrane potential, promoted the expression of cytochrome c (CytC), and decreased the cell survival rate. Furthermore, ZEA + DON increased the relative mRNA and protein expression of Bid, Caspase-3, Drp1, and P53, while that of Bcl-2 and Mfn2 declined. ZEA + DON was added after pretreatment with 4-phenylbutyric acid (4-PBA). The results showed that 4-PBA could alleviate the toxicity of ZEA + DON toward SCs. Compared with the ZEA + DON group, 4-PBA improved the cell survival rate, decreased the apoptosis rate, inhibited CytC expression, and increased mitochondrial membrane potential, and the damage to the cell ultrastructure was alleviated. Moreover, after pretreatment with 4-PBA, the relative mRNA and protein expression of Bid, Caspase-3, Drp1, and P53 were downregulated, while the relative mRNA and protein expression of Bcl-2 and Mfn2 were upregulated. It can be concluded that ERS plays an important part in the apoptosis of SCs co-infected with ZEA-DON through the mitochondrial apoptosis pathway, and intervention in this process can provide a new way to alleviate the reproductive toxicity of mycotoxins.

Zearalenone induces mitochondria-associated endoplasmic reticulum membranes dysfunction in piglet Sertoli cells based on endoplasmic reticulum stress

Zearalenone (ZEA) is an estrogen-like mycotoxin, which mainly led to reproductive toxicity. The study aimed to investigate the molecular mechanism of ZEA-induced dysfunction of mitochondria-associated endoplasmic reticulum membranes (MAM) in piglet Sertoli cells (SCs) via the endoplasmic reticulum stress (ERS) pathway. In this study, SCs were used as a research object that was exposed to ZEA, and ERS inhibitor 4-Phenylbutyrate acid (4-PBA) was used as a reference. The results showed that ZEA damaged cell viability and increased Ca²⁺ levels; damaged the structure of MAM; up-regulated the relative mRNA and protein expression of glucose-regulated protein 75 (Grp75) and mitochondrial Rho-GTPase 1 (Miro1), while inositol 1,4,5-trisphosphate receptor (IP3R), voltage-dependent anion channel 1 (VDAC1), mitofusin2 (Mfn2) and phosphofurin acidic cluster protein 2 (PACS2) were down-regulated. After a 3 h 4-PBA-pretreatment, ZEA was added for mixed culture. The results of 4-PBA pretreatment showed that inhibition of ERS reduced the cytotoxicity of ZEA against piglet SCs. Compared with the ZEA group, inhibition of ERS increased cell viability and decreased Ca²⁺ levels; restored the structural damage of MAM; down-regulated the relative mRNA and protein expression of Grp75 and Miro1; and up-regulated the relative mRNA and protein expression of IP3R, VDAC1, Mfn2, and PACS2. In conclusion, ZEA can induce MAM dysfunction in piglet SCs via the ERS pathway, whereas ER can regulate mitochondria through MAM.

Inhibition of Mitochondrial Fission Alleviates Zearalenone-Induced Mitochondria-Associated Endoplasmic Reticulum Membrane Dysfunction in Piglet Sertoli Cells

This study aimed to investigate the effects of zearalenone (ZEA) on piglet Sertoli cell (SC)-mitochondria-associated endoplasmic reticulum (ER) membranes (MAMs) based on mitochondrial fission, and to explore the molecular mechanism of ZEA-induced cell damage. After the SCs were exposed to the ZEA, the cell viability decreased, the Ca2+ levels increased, and the MAM showed structural damage. Moreover, glucose-regulated protein 75 (Grp75) and mitochondrial Rho-GTPase 1 (Miro1) were upregulated at the mRNA and protein levels. However, phosphofurin acidic cluster protein 2 (PACS2), mitofusin2 (Mfn2), voltage-dependent anion channel 1 (VDAC1), and inositol 1,4,5-trisphosphate receptor (IP3R) were downregulated at the mRNA and protein levels. A pretreatment with mitochondrial division inhibitor 1 (Mdivi-1) decreased the ZEA-induced cytotoxicity toward the SCs. In the ZEA + Mdivi-1 group, the cell viability increased, the Ca2+ levels decreased, the MAM damage was repaired, and the expression levels of Grp75 and Miro1 decreased, while those of PACS2, Mfn2, VDAC1, and IP3R increased compared with those in the ZEA-only group. Thus, ZEA causes MAM dysfunction in piglet SCs through mitochondrial fission, and mitochondria can regulate the ER via MAM.

The Mycotoxin De-Epoxy-Deoxynivalenol (DOM-1) Increases Endoplasmic Reticulum Stress in Ovarian Theca Cells

Deoxynivalenol (DON) is a major mycotoxin present in animal feed and negatively affects growth and reproduction in farm species, including pigs and cattle. The mechanism of DON action involves the ribotoxic stress response (RSR), and it acts directly on ovarian granulosa cells to increase cell death. In ruminants, DON is metabolized to de-epoxy-DON (DOM-1), which cannot activate the RSR but has been shown to increase cell death in ovarian theca cells. In the present study, we determined if DOM-1 acts on bovine theca cells through endoplasmic stress using an established serum-free cell culture model and to assess whether also DON activates endoplasmic stress in granulosa cells. The results show that DOM-1 increased the cleavage of ATF6 protein, increased the phosphorylation of EIF2AK3, and increased the abundance of cleaved XBP1 mRNA. Activation of these pathways led to an increased abundance of mRNA of the ER stress target genes GRP78, GRP94, and CHOP. Although CHOP is widely associated with autophagy, inhibition of autophagy did not alter the response of theca cells to DOM-1. The addition of DON to granulosa cells partially increased ER stress pathways but failed to increase the abundance of mRNA of ER stress target genes. We conclude that the mechanism of action of DOM-1, at least in bovine theca cells, is through the activation of ER stress.

Autophagy regulates inflammation in intracerebral hemorrhage: Enemy or friend?

Intracerebral hemorrhage (ICH) is the second-largest stroke subtype and has a high mortality and disability rate. Secondary brain injury (SBI) is delayed after ICH. The main contributors to SBI are inflammation, oxidative stress, and excitotoxicity. Harmful substances from blood and hemolysis, such as hemoglobin, thrombin, and iron, induce SBI. When cells suffer stress, a critical protective mechanism called "autophagy" help to maintain the homeostasis of damaged cells, remove harmful substances or damaged organelles, and recycle them. Autophagy plays a critical role in the pathology of ICH, and its function remains controversial. Several lines of evidence demonstrate a pro-survival role for autophagy in ICH by facilitating the removal of damaged proteins and organelles. However, many studies have found that heme and iron can aggravate SBI by enhancing autophagy. Autophagy and inflammation are essential culprits in the progression of brain injury. It is a fascinating hypothesis that autophagy regulates inflammation in ICH-induced SBI. Autophagy could degrade and clear pro-IL-1β and apoptosis-associated speck-like protein containing a CARD (ASC) to antagonize NLRP3-mediated inflammation. In addition, mitophagy can remove endogenous activators of inflammasomes, such as reactive oxygen species (ROS), inflammatory components, and cytokines, in damaged mitochondria. However, many studies support the idea that autophagy activates microglia and aggravates microglial inflammation via the toll-like receptor 4 (TLR4) pathway. In addition, autophagy can promote ICH-induced SBI through inflammasome-dependent NLRP6-mediated inflammation. Moreover, some resident cells in the brain are involved in autophagy in regulating inflammation after ICH. Some compounds or therapeutic targets that regulate inflammation by autophagy may represent promising candidates for the treatment of ICH-induced SBI. In conclusion, the mutual regulation of autophagy and inflammation in ICH is worth exploring. The control of inflammation by autophagy will hopefully prove to be an essential treatment target for ICH.

Neuroprotective effect of naringenin-loaded solid lipid nanoparticles against streptozocin-induced neurotoxicity through autophagy blockage

Autophagy is a pivotal contributing factor to modulate the progression of neurodegenerative diseases. Although naringenin (Nar) has shown beneficial effects against neurodegenerative diseases, its poor solubility and bioavailability have limited its application. The present research aimed to design a nanostructured formulation of Nar to achieve an enhanced therapeutic effect. Herein, Nar-loaded solid lipid nanoparticles (Nar-SLNs) were prepared and characterized. Then, PC12 cells were exposed to streptozocin (STZ) and/or Nar and Nar-SLNs in vitro to clarify the protective effect of Nar and its nanoformulation against STZ-stimulated neurotoxicity. The empty SLNs and Nar-SLNs indicated a narrow polydispersity index value with a negative zeta potential. As determined by the scanning electron microscopy images, the nanoparticles had a spherical shape and were less than 20 nm in size. FTIR results demonstrated the interaction between Nar and SLNs and supported the presence of Nar in the nanoparticle. The nanoformulation revealed an initial burst release followed by a sustained release manner. Treatment of PC12 cells with STZ resulted in mitochondrial dysfunction and increased autophagic markers, including LC3-II, Beclin1, Akt, ATG genes, and accumulation of miR-21 and miR-22. Both Nar and Nar-SLNs pre-treatment improved cell survival and augmented mitochondrial membrane potential, accompanied by reduced autophagic markers expression. However, Nar-SLNs were more effective than free Nar. As a result, our findings suggested that SLNs effectively enhance the neuroprotective effect of Nar, and Nar-SLNs may be a promising candidate to suppress or prevent STZ-elicited neurotoxicity. PRACTICAL APPLICATIONS: According to the beneficial effect of Nar in the management of neurodegenerative diseases, we evaluated the protective effect of Nar and Nar-SLNs against STZ-stimulated neurotoxicity and analyzed the role of autophagy in STZ-stimulated neurotoxicity. Our results proposed that Nar-SLNs could be a promising option for neurological disorders prevention through autophagy suppression.

QishenYiqi dripping pill protects against myocardial ischemia/reperfusion injury via suppressing excessive autophagy and NLRP3 inflammasome based on network pharmacology and experimental pharmacology

Background: Myocardial ischemia/reperfusion (I/R) injury is associated with multiple serious clinical manifestations. Autophagy is upregulated in a short period of ischemia and further enhanced during reperfusion phase, which was considered as a “double-edged sword” in the pathological process of myocardial I/R injury. In addition, NLRP3 inflammasome triggers myocardial inflammatory response, which leads to cardiomyocyte death via pyroptosis and promotes subsequent myocardial remodelling. Qishen Yiqi Dripping Pill (QSYQ) has been recognized as a potential protective agent of cardiovascular diseases.

Objective: We predicted the bioactive compounds, targets and pathways of OSYQ intervening on myocardial I/R injury by network pharmacology. Furthermore, we investigated the effect of QSYQ on myocardial I/R injury and explored its underlying mechanism via autophagy and NLRP3 Inflammasome.

Methods: Bioactive compounds, targets of QSYQ and relevant targets of myocardial I/R injury were collected from public databases. The protein-protein interaction network, Gene ontology and KEGG pathway enrichment analysis were carried out to screen the key compounds, target genes, functional annotation and pivotal pathways. Molecular docking was used to validate the binding association between target genes and key bioactive ingredients. Furthermore, sixty SD rats were randomized into four groups: 1) sham, 2) model, 3) captopril and 4) QSYQ pretreatment (14 days before and after surgery). Each arm was subjected to ischemia/reperfusion surgery except sham arm (30 min coronary ligation, then reperfusion). Left ventricular (LV) function were evaluated and the hearts were used to evaluate size of myocardial infarction, cardiomyocyte fibrosis, and myocardial autophagosomes.

Results: The network pharmacology revealed the mechanism of QSYQ intervening on myocardial I/R injury might be related to NOD-like receptor signaling pathway, PI3K-Akt signaling pathway, autophagy-animal, etc., Molecular-docking suggested the core target proteins had good binding association with bioactive compounds of QSYQ. The experiment confirmed that QSYQ attenuated myocardial infarct size, decreased inflammatory infiltration and collagen fiber deposition and alleviated the autophagosome and myocardium ultrastructure injury, leading to LV systolic function improvement. The possible mechanism of cardioprotection was due to regulating autophagy-related proteins, activating PI3K/Akt-mTOR signaling pathway, and inhibiting activation and assembly of NLRP3 inflammasome.

Conclusion: QSYQ ameliorated myocardial I/R injury via suppressing excessive autophagy and NLRP3 Inflammasome.

A review on therapeutical potential of paeonol in atherosclerosis

The morbidity and mortality of atherosclerotic cardiovascular disease (ASCVD) is increasing year by year. Cortex Moutan is a traditional Chinese medicinal herb that has been widely used for thousands of years to treat a wide variety of diseases in Eastern countries due to its heat-clearing and detoxifying effects. Paeonol is a bioactive monomer extracted from Cortex Moutan, which has anti-atherosclerotic effects. In this article, we reviewed the pharmacological effects of paeonol against experimental atherosclerosis, as well as its protective effects on vascular endothelial cells, smooth muscle cells, macrophages, platelets, and other important cell types. The pleiotropic effects of paeonol in atherosclerosis suggest that it can be a promising therapeutic agent for atherosclerosis and its complications. Large-scale randomized clinical trials are warranted to elucidate whether paeonol are effective in patients with ASCVD.

Inhibitory Effect of Ursolic Acid on Proliferation and Migration of Renal Carcinoma Cells and Its Mechanism

Background

Renal carcinoma is one of the most common malignant tumors in the urinary system. Autophagy can be both activated and inhibited in renal carcinoma, and it plays a double-edged role in the development of renal carcinoma. In the early stage of cancer, autophagy can suppress tumors. In the late stage, autophagy contributes to the survival of tumor cells in an unfavorable environment, and some autophagy-related proteins P62, LC3B, and beclin-1 have become indicators of the prognosis of patients with renal carcinoma.

Aim

To demonstrate that ursolic acid activates autophagy in renal carcinoma 786-O cells by inhibiting the hedgehog signaling pathway.

Methods

The effect of ursolic acid on the viability of 786-O cells was determined by the MTT method; the effect of ursolic acid on the proliferation and migration of 786-O cells was examined by crystalline violet staining and scratch assay, respectively. For the study of autophagy, we firstly screened the time points. Western blot assay was used to detect the expression level of autophagic protein P62 at different time points of ursolic acid on 786-O. Then, the Cell MeterTM Autophagy Assay Kit was used to detect the effect of different doses of ursolic acid on the autophagic fluorescence intensity of 786-O cells; the Western blot method was used to detect the effect of different doses of ursolic acid on the expression levels of LC3II and P62 proteins in 786-O cells. Further, AdPlus-mCherry-GFP-LC3B adenovirus transfection was used to detect the effect of ursolic acid on the autophagic flow of 786-O cells; ursolic acid was combined with the autophagy inhibitor chloroquine (CQ) to detect the expression level of autophagy protein LC3II by Western blot. In terms of mechanism, the effect of ursolic acid on hedgehog signaling pathway-related proteins in 786-O cells was detected by Western blot.

Results

Ursolic acid inhibited the activity, proliferation, and migration of 786-O cells, enhanced the fluorescence intensity of autophagosomes in 786-O cells, increased the expression level of autophagy marker protein LC3II, and inhibited the expression level of P62 in a time and dose-dependent manner; ursolic acid activated the autophagic flow in 786-O cells, which showed that ursolic acid caused the accumulation of autophagic fluorescent spots and enhanced the fluorescence intensity of autophagosomes. Ursolic acid activated the autophagic flow in 786-O cells, as evidenced by the accumulation of autophagic fluorescent spots and enhanced fluorescence intensity of autophagosomes, and the combined use of the autophagy inhibitor CQ increased the expression level of LC3II compared to ursolic acid alone; ursolic acid decreased the expression levels of PTCH1, GLI1, SMO, SHH, and c-Myc and increased the expression level of Sufu in the hedgehog signaling pathway.

Conclusion

Ursolic acid activates autophagy in renal carcinoma 786-O cells, probably by inhibiting hedgehog signaling pathway activity.

Deoxynivalenol induces apoptosis and autophagy in human prostate epithelial cells via PI3K/Akt signaling pathway

Phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway is one of the most deregulated signaling pathway in prostate cancer. It controls basic processes in cells: cell proliferation and death. Any disturbances in the balance between cell death and survival might result in carcinogenesis. Deoxynivalenol (DON) is one of the most common mycotoxins, a toxic metabolites of fungi, present in our everyday diet and feed. Although previous studies reported DON to induce oxidative stress, modulate steroidogenesis, DNA damage and cell cycle modulation triggering together its toxicity, its effect on normal prostate epithelial cells is not known. The aim of the study was to evaluate the effect of DON on the apoptosis and autophagy in normal prostate epithelial cells via modulation of PI3K/Akt signaling pathway. The results showed that DON in a dose of 30 µM and 10 µM induces oxidative stress, DNA damage and cell cycle arrest in G2/M cell cycle phase. The higher concentration of DON induces apoptosis, whereas lower one autophagy in PNT1A cells, indicating that modulation of PI3K/Akt by DON results in the induction of autophagy triggering apoptosis in normal prostate epithelial cells.

Lactobacillus plantarum metabolites reduce deoxynivalenol toxicity on jejunal explants of piglets

The deterioration of food and feed stuffs and toxic intestinal effects due to fungal colonization and concomitant production of mycotoxins is an increasing concern. The development of fungi resistance to many commonly used chemical preservatives adds further alarm. Therefore, effective detoxification methods would be useful in counteracting this problem. Biotransformation/adsorption of mycotoxins by lactic acid bacteria and their metabolites is a promising approach to minimize the deleterious effects of mycotoxins. The objective of the present study was to evaluate the beneficial effects of Lactobacillus plantarum metabolites in reducing deoxynivalenol intestinal toxicity. To achieve this aim, histological, morphometrical and oxidative stress analyses were performed in the intestinal mucosa of piglets exposed to deoxynivalenol alone or associated with two strains (SN1 and SN2) of L. plantarum subsp. plantarum metabolites. Metabolites were obtained after dichloromethane (D) or ethyl acetate (A) extraction. Jejunal explants were exposed to the following treatments for 2 and 4 h a) culture medium (control group); b) deoxynivalenol (DON, 10 μM); c) L. plantarum metabolites DSN1; d) L. plantarum metabolites DSN1+DON; e) L. plantarum metabolites DSN2; f) L. plantarum metabolites DSN2+DON; g) L. plantarum metabolites ASN1; h) L. plantarum metabolites ASN1+DON; i) L. plantarum metabolites ASN2; j) L. plantarum metabolites ASN2+DON. The metabolites were incubated 1 h previously to DON challenge (one and 3 h of exposure). Histological assessment showed DON-treated explants with villi fusion and atrophy, multifocal apical necrosis and cuboid or flattened enterocytes with 2 and 4 h of exposure, while LP metabolites groups individually or associated with DON remained like control. The density of goblet cells in villi and crypts was reduced in DON explants compared to control group with 2 and 4 h of exposure; on the other hand, a significant increase in this parameter was achieved in LP metabolites groups compared to DON. Morphometric evaluation showed no difference in villi height or crypts depth in any treated explants. Overall, oxidative stress response assessments showed that explants exposed to SN1 extracted with dichloromethane and ethyl acetate, and SN2 extracted with dichloromethane reduced superoxide anion production. In conclusion, L. plantarum metabolites induced beneficial effects in intestinal mucosa, reducing the toxic effects of DON on intestinal morphology and oxidative response.

Extracellular IL-37 promotes osteogenic and odontogenic differentiation of human dental pulp stem cells via autophagy

The osteogenic and odontogenic differentiation of dental pulp stem cells (DPSCs) contribute to restoration and regeneration of dental tissue. Previous study indicated that interleukin-37 (IL-37) was an anti-inflammatory factor that affected other pro-inflammatory signals. The aim of this study was to explore the effects of IL-37 on the differentiation of DPSCs. DPSCs were cultured in growth medium with different concentrations of IL-37. We selected the optimal concentration for the following experiments by alkaline phosphatase (ALP) activity analysis, quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and Western blot. Cell counting kit assay (CCK-8) and 5-Ethynyl-2'-Deoxyuridine (EdU) assay were conducted to assess the effects of IL-37 on the proliferation of DPSCs. ALP activity assay and staining, alizarin red S (ARS) staining, qRT-PCR, Western blot as well as immunofluorescence staining were conducted to assess differentiation ability of DPSCs. Western blot, immunofluorescence staining and transmission electron microscopy (TEM) were utilized to examine cell autophagy. Results showed that IL-37 enhanced the osteogenic and odontogenic differentiation ability of DPSCs with no significant influence on the proliferation of DPSCs. Autophagy in DPSCs was activated by IL-37. Activation of autophagy enhanced osteogenesis and odontogenesis of DPSCs, whereas inhibition of autophagy suppressed DPSCs osteogenic and odontogenic differentiation. In conclusion, IL-37 increased osteogenic and odontogenic differentiation via autophagy.

Quercetin Alleviates the Accumulation of Superoxide in Sodium Iodate-Induced Retinal Autophagy by Regulating Mitochondrial Reactive Oxygen Species Homeostasis through Enhanced Deacetyl-SOD2 via the Nrf2-PGC-1α-Sirt1 Pathway

Oxidative damage of retinal pigment epithelium (RPE) cells plays an important role in the pathogenesis of blindness-related diseases, such as age-related macular degeneration (AMD). Quercetin, a bioactive flavonoid compound, has been shown to have a protective effect against oxidative stress-induced cell apoptosis and inflammation in RPE cells; however, the detailed mechanism underlying this protective effect is unclear. Therefore, the aim of this study was to investigate the regulatory mechanism of quercetin in a sodium iodate (NaIO₃)-induced retinal damage. The clinical features of the mice, the production of oxidative stress, and the activity of autophagy and mitochondrial biogenesis were examined. In the mouse model, NaIO₃ treatment caused changes in the retinal structure and reduced pupil constriction, and quercetin treatment reversed the oxidative stress-related pathology by decreasing the level of superoxide dismutase 2 (SOD2) while enhancing the serum levels of catalase and glutathione. The increased level of reactive oxygen species in the NaIO₃-treated ARPE19 cells was improved by treatment with quercetin, accompanied by a reduction in autophagy and mitochondrial biogenesis. Our findings indicated that the effects of quercetin on regulating the generation of mtROS were dependent on increased levels of deacetyl-SOD2 through the Nrf2-PGC-1α-Sirt1 signaling pathway. These results demonstrated that quercetin may have potential therapeutic efficacy for the treatment of AMD through the regulation of mtROS homeostasis.

Hypoxia, oxidative stress, and immune evasion: a trinity of the trichothecenes T-2 toxin and deoxynivalenol (DON)

T-2 toxin and deoxynivalenol (DON) are type A and B trichothecenes, respectively. They widely occur as pollutants in food and crops and cause a series of toxicities, including immunotoxicity, hepatotoxicity, and neurotoxicity. Oxidative stress is the primary mechanistic basis of these toxic effects. Increasing amounts of evidence have shown that mitochondria are significant targets of apoptosis caused by T-2 toxin- and DON-induced oxidative stress via regulation of Bax/B-cell lymphoma-2 and caspase-3/caspase-9 signaling. DNA methylation and autophagy are involved in oxidative stress related to apoptosis, and hypoxia and immune evasion are related to oxidative stress in this context. Hypoxia induces oxidative stress by stimulating mitochondrial reactive oxygen species production and regulates the expression of cytokines, such as interleukin-1β and tumor necrosis factor-α. Programmed cell death-ligand 1 is upregulated by these cytokines and by hypoxia-inducible factor-1, which allows it to bind to programmed cell death-1 to enable escape of immune cell surveillance and achievement of immune evasion. This review concentrates on novel findings regarding the oxidative stress mechanisms of the trichothecenes T-2 toxin and DON. Importantly, we discuss the new evidence regarding the connection of hypoxia and immune evasion with oxidative stress in this context. Finally, the trinity of hypoxia, oxidative stress and immune evasion is highlighted. This work will be conducive to an improved understanding of the oxidative stress caused by trichothecene mycotoxins.

Deoxynivalenol Induces Caspase-8-Mediated Apoptosis through the Mitochondrial Pathway in Hippocampal Nerve Cells of Piglet

Deoxynivalenol (DON) is a common trichothecene mycotoxin found worldwide. DON has broad toxicity towards animals and humans. However, the mechanism of DON-induced neurotoxicity in vitro has not been fully understood. This study investigated the hypothesis that DON toxicity in neurons occurs via the mitochondrial apoptotic pathway. Using piglet hippocampal nerve cells (PHNCs), we evaluated the effects of different concentrations of DON on typical indicators of apoptosis. The obtained results demonstrated that DON treatment inhibited PHNC proliferation and led to morphological, biochemical, and transcriptional changes consistent with apoptosis, including decreased mitochondrial membrane potential, mitochondrial release of cytochrome C (CYCS) and apoptosis inducing factor (AIF), and increased abundance of active cleaved-caspase-9 and cleaved-caspase-3. Increasing concentrations of DON led to decreased B-cell lymphoma-2 (Bcl-2) expression and increased expression of BCL2-associated X (Bax) and B-cell lymphoma-2 homology 3 interacting domain death agonist (Bid), which in turn increased transcriptional activity of the transcription factors AIF and P53 (a tumor suppressor gene, promotes apoptosis). The addition of a caspase-8 inhibitor abrogated these effects. These results reveal that DON induces apoptosis in PHNCs via the mitochondrial apoptosis pathway, and caspase-8 is shown to play an important role during apoptosis regulation.

An update on T-2 toxin and its modified forms: metabolism, immunotoxicity mechanism, and human exposure assessment

T-2 toxin is the most toxic trichothecene mycotoxin, and it exerts potent toxic effects, including immunotoxicity, neurotoxicity, and reproductive toxicity. Recently, several novel metabolites, including 3',4'-dihydroxy-T-2 toxin and 4',4'-dihydroxy-T-2 toxin, have been uncovered. The enzymes CYP3A4 and carboxylesterase contribute to T-2 toxin metabolism, with 3'-hydroxy-T-2 toxin and HT-2 toxin as the corresponding primary products. Modified forms of T-2 toxin, including T-2-3-glucoside, exert their immunotoxic effects by signaling through JAK/STAT but not MAPK. T-2-3-glucoside results from hydrolyzation of the corresponding parent mycotoxin and other metabolites by the intestinal microbiota, which leads to enhanced toxicity. Increasing evidence has shown that autophagy, hypoxia-inducible factors, and exosomes are involved in T-2 toxin-induced immunotoxicity. Autophagy promotes the immunosuppression induced by T-2 toxin, and a complex crosstalk between apoptosis and autophagy exists. Very recently, "immune evasion" activity was reported to be associated with this toxin; this activity is initiated inside cells and allows pathogens to escape the host immune response. Moreover, T-2 toxin has the potential to trigger hypoxia in cells, which is related to activation of hypoxia-inducible factor and the release of exosomes, leading to immunotoxicity. Based on the data from a series of human exposure studies, free T-2 toxin, HT-2 toxin, and HT-2-4-glucuronide should be considered human T-2 toxin biomarkers in the urine. The present review focuses on novel findings related to the metabolism, immunotoxicity, and human exposure assessment of T-2 toxin and its modified forms. In particular, the immunotoxicity mechanisms of T-2 toxin and the toxicity mechanism of its modified form, as well as human T-2 toxin biomarkers, are discussed. This work will contribute to an improved understanding of the immunotoxicity mechanism of T-2 toxin and its modified forms.