Exosomes mediated the delivery of ochratoxin A-induced cytotoxicity in HEK293 cells

Dual-mode detection of Ochratoxin A based on silver nanocluster and phosphate

Ochratoxin A (OTA) is widely present in the environment and has great harm to human safety. Therefore, a simple and sensitive method for OTA detection is urgently needed. Herein, a fluorescence and colorimetric dual-mode immunoassay based on glutathione silver nanocluster (GSH-AgNCs) and phosphate colorimetry was established. For fluorescence mode, the pyrophosphate ion (PPi) can reduce the fluorescence of GSH-AgNCs@Al3+ by chelating Al3+. Meanwhile, the fluorescence can be recovered when PPi is hydrolyzed to phosphate ion (Pi) by alkaline phosphatase (ALP.) For colorimetric mode, Pi can be quantitatively analyzed by MoSb colorimetric method. The linear range of fluorescence mode was 1.25-35 ng/mL with limit of detection (LOD) of 0.54 ng/mL. For colorimetric mode, the linear range and LOD was 6.25-250 ng/mL and 3.13 ng/mL. The detection limits are much lower than the European Union's regulations. And this dual-mode immunoassay showed a satisfactory recovery rate and specificity in detecting real samples.

7-Hydroxycoumarin and its conjugated metabolites interact with organic anion transporters 1 and 3 in vitro and in vivo

7-Hydroxycoumarin (7-HC) is a natural coumarin compound rich in Chinese herbal medicines and has various pharmacological activities. After oral administration of 7-HC in rodents, its conjugated metabolites 7-hydroxycoumarin-β-D-glucuronide (7-HCG) and 7-hydroxycoumarin sulfate (7-HCS), exhibit high systemic exposure and urinary excretion. Organic anion transporters 1 and 3 (OAT1 and OAT3), mainly expressed in the proximal renal tubules, play an important role in drug-drug interactions and drug-induced kidney injury. We aimed to explore the mechanisms of OAT-mediated drug interactions and renal protective mechanisms of 7-HC and its conjugates. OAT-overexpressing cell models revealed that 7-HC was not a substrate for OAT1 and OAT3, while 7-HCG was specifically transported by OAT3. In contrast, 7-HCS can be transported by both OATs. Besides, 7-HC significantly inhibited the activity of OAT1 and OAT3, while 7-HCS had a strong inhibitory effect on OAT1 (IC50 < 10 μM). After co-administration of 100 mg/kg of 7-HC to mice, systemic exposure and clearance of furosemide (a clinical substrate of OATs) were significantly increased and decreased, respectively. In addition, 7-HC decreased OAT-mediated cytotoxicity and reduced the renal distribution of adefovir in mice. Together, these findings will provide support for OAT-mediated drug interactions and the renal protection of 7-HC.

Exosomes as mediators of signal transmitters in biotoxins toxicity: a comprehensive review

Small membranes known as exosomes surround them and are released by several cell types both in vitro and in vivo. These membranes are packed with a variety of biomolecules, including proteins, lipids, deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and non-coding RNA (ncRNA). As a source of biological nanomaterials, exosomes play a role in information and substance transmission between cells and have been identified as a general method of facilitating communication during interactions between the body, target organs, and toxins.. In order to understand the changes and mechanism of the composition and level of exosomes after biotoxin infection, this review focuses on current findings on the exosomes and highlights their novel uses in the toxicity mechanism. Exosomes are mainly used as a delivery carrier or mediated by receptors, and play an immune role after the toxin enters the body. This review expounds on the importance of exosomes in the toxicological mechanism of biotoxins and provides new insights for further diagnosis of toxic biomarkers, detoxification, and treatment development.

Ratiometric fluorescence immunoassay based on silver nanoclusters and calcein-Ce3+ for detecting ochratoxin A

Ochratoxin A (OTA), a dangerous mycotoxin, is found in many crops. It is essential to create sensitive OTA detection techniques to ensure food safety. Based on the principle of p-nitrophenol (PNP) quenched the fluorescence of bovine serum albumin silver nanocluster (BSA-AgNCs) through an internal filtering effect, and phosphate activated fluorescence of calcein-Ce3+ system, a ratiometric fluorescence immunoassay for OTA detection was developed. In this strategy, the value of F518/F640 was used as a signal for response of OTA concentration. The detection range of this strategy was 0.625-25 ng/mL, the limit of detection (LOD) was 0.04 ng/mL. This new immunoassay offered a brand-new platform for detecting OTA.

Blocking exosomal secretion aggravated 1,4-benzoquinone-induced cytotoxicity

Benzene exposure inhibits the hematopoietic system and leads to the occurrence of various types of leukemia. However, the mechanism underlying the hematotoxicity of benzene is still largely unclear. Emerging evidence has shown that exosomes are involved in toxic mechanisms of benzene. To understand the effect of 1,4-benzoquinone (PBQ; an active metabolite of benzene in bone marrow) on the exosomal release characteristics and role of exosomal secretion in PBQ-induced cytotoxicity. Exosomes were isolated from PBQ-treated HL-60 cells, purified by ultracentrifugation, and verified by transmission electron microscopy, nanoparticle tracking analysis and the presence of specific biomarkers. Our results showed that PBQ increased exosomal secretion in a dose-dependent manner, reaching a peak in 3 h at 10 μM PBQ treatment and then slowly decreasing in HL-60 cells. The exosomes contained miRNAs, which have been reported to be associated with benzene exposure or benzene poisoning. In particular, mir-34a-3p and mir-34A-5p were enriched in exosomes derived from PBQ-treated cells. In addition, the inhibition of exosomal release by GW4869 (an inhibitor of exosomal release) exacerbated PBQ-induced cytotoxicity, including increased intracellular reactive oxygen species levels, decreased mitochondrial membrane potential, and increased the apoptosis rate. Our findings illustrated that exosomes secretion plays an important role in antagonizing PBQ-induced cytotoxicity and maintaining cell homeostasis.

Alkaline phosphatase triggered gold nanoclusters turn-on fluorescence immunoassay for detection of Ochratoxin A

Ochratoxin A (OTA) is a highly toxic mycotoxin which can cause a variety of diseases. Sensitive detection of OTA is significant for food safety. Herein, a feasible and sensitive immunoassay was established for OTA detection by alkaline phosphatase (ALP) triggered gold nanoclusters (AuNCs) turn-on fluorescence. The fluorescence of the AuNCs can be quenched by Cr6+ induced aggregation of AuNCs and the fluorescence resonance energy transfer (FRET) between AuNCs and Cr6+. Under the catalytic action of ALP-labelled IgG (IgG-ALP), the ascorbic acid 2-phosphate (AA2P) was hydrolyzed to ascorbic acid (AA) for the reducing of Cr6+ to Cr3+. As a result, the degrees of AuNCs aggregation and FRET were weakened and the fluorescence of AuNCs was turned on. The amount of OTA in the sample was negatively correlated with the amount of IgG-ALP captured by anti-OTA monoclonal antibody (McAb) in the microplate. In optimal conditions, the turn-on fluorescence immunoassay had a good linear range of 6.25-100 ng/mL, and the detection limit was 0.693 ng/mL. The recoveries of OTA from corn were 95.89%-101.08% for the fluorescence immunoassay. This work provided a feasible, sensitive and good selectivity fluorescence method for OTA detection.

Molecular Docking and In Vitro Studies of Ochratoxin A (OTA) Biodetoxification Testing Three Endopeptidases

Ochratoxin A (OTA) is considered one of the main mycotoxins responsible for health problems and considerable economic losses in the feed industry. The aim was to study OTA's detoxifying potential of commercial protease enzymes: (i) Ananas comosus bromelain cysteine-protease, (ii) bovine trypsin serine-protease and (iii) Bacillus subtilis neutral metalloendopeptidase. In silico studies were performed with reference ligands and T-2 toxin as control, and in vitro experiments. In silico study results showed that tested toxins interacted near the catalytic triad, similar to how the reference ligands behave in all tested proteases. Likewise, based on the proximity of the amino acids in the most stable poses, the chemical reaction mechanisms for the transformation of OTA were proposed. In vitro experiments showed that while bromelain reduced OTA's concentration in 7.64% at pH 4.6; trypsin at 10.69% and the neutral metalloendopeptidase in 8.2%, 14.44%, 45.26% at pH 4.6, 5 and 7, respectively (p < 0.05). The less harmful α-ochratoxin was confirmed with trypsin and the metalloendopeptidase. This study is the first attempt to demonstrate that: (i) bromelain and trypsin can hydrolyse OTA in acidic pH conditions with low efficiency and (ii) the metalloendopeptidase was an effective OTA bio-detoxifier. This study confirmed α-ochratoxin as a final product of the enzymatic reactions in real-time practical information on OTA degradation rate, since in vitro experiments simulated the time that food spends in poultry intestines, as well as their natural pH and temperature conditions.

The impact of environmental contaminants on extracellular vesicles and their key molecular regulators: A literature and database-driven review

Exposure to environmental chemicals is now well recognized as a significant factor contributing to the global burden of disease; however, there remain critical gaps in understanding the types of biological mechanisms that link environmental chemicals to adverse health outcomes. One type of mechanism that remains understudied involves extracellular vesicles (EVs), representing small cell-derived particles capable of carrying molecular signals such as RNAs, miRNAs, proteins, lipids, and chemicals through biological fluids and imparting beneficial, neutral, or negative effects on target cells. In fact, evidence is just now starting to grow that supports the role of EVs in various disease etiologies. This review aims to (1) Provide a landscape of the current understanding of the functional relationship between EVs and environmental chemicals; (2) Summarize current knowledge of EV regulatory processes including production, packaging, and release; and (3) Conduct a database-driven analysis of known chemical-gene interactions to predict and prioritize environmentally relevant chemicals that may impact EV regulatory genes and thus EV regulatory processes. This approach to predicting environmentally relevant chemicals that may alter EVs provides a novel method for evidence-based hypothesis generation for future studies evaluating the link between environmental exposures and EVs.

New insights of engineering plant exosome-like nanovesicles as a nanoplatform for therapeutics and drug delivery

Plant exosome-like nanovesicles (PELNVs) are membrane-encapsulated nanostructures released from cells into their surroundings. PELNVs have an important role in intercellular and interspecies communication in all three domains of life. They act as protective compartments for the long-distance transit of signal molecules like proteins, nucleic acids, lipids, and other metabolites. A range of plants and vegetables can emit PELNVs. The importance of PELNVs in interspecies communication stems from their concentration in biomolecules (lipids, proteins, and miRNAs), lack of toxicity, ease of internalization by cells, and anti-inflammatory, immune-modulatory, and regenerative characteristics. PELNVs derived from numerous fruits and vegetables are biocompatible, biodegradable, and abundant in various plant species. Moreover, their convincing physicochemical characteristics underpin their modulative role in physiological and pathological processes, all of which have fueled speculation that these nanovesicles could be particularly adept at developing future-generation bio-therapeutic platforms. The goal of this review was not only to present an overview of the identified roles of PELNVs in physiology and pathology, but also to provide new insight toward their engineering for effective therapeutics and drug delivery nanoplatforms, a clue for future direction to the ongoing research gaps.