Metabolomics revealed the toxicity of cationic liposomes in HepG2 cells using UHPLC-Q-TOF/MS and multivariate data analysis

1H NMR spectroscopic characterisation of HepG2 cells as a model metabolic system for toxicology studies

The immortalised human hepatocellular HepG2 cell line is commonly used for toxicology studies as an alternative to animal testing due to its characteristic liver-distinctive functions. However, little is known about the baseline metabolic changes within these cells upon toxin exposure. We have applied 1H Nuclear Magnetic Resonance (NMR) spectroscopy to characterise the biochemical composition of HepG2 cells at baseline and post-exposure to hydrogen peroxide (H2O2). Metabolic profiles of live cells, cell extracts, and their spent media supernatants were obtained using 1H high-resolution magic angle spinning (HR-MAS) NMR and 1H NMR spectroscopic techniques. Orthogonal partial least squares discriminant analysis (O-PLS-DA) was used to characterise the metabolites that differed between the baseline and H2O2 treated groups. The results showed that H2O2 caused alterations to 10 metabolites, including acetate, glutamate, lipids, phosphocholine, and creatine in the live cells; 25 metabolites, including acetate, alanine, adenosine diphosphate (ADP), aspartate, citrate, creatine, glucose, glutamine, glutathione, and lactate in the cell extracts, and 22 metabolites, including acetate, alanine, formate, glucose, pyruvate, phenylalanine, threonine, tryptophan, tyrosine, and valine in the cell supernatants. At least 10 biochemical pathways associated with these metabolites were disrupted upon toxin exposure, including those involved in energy, lipid, and amino acid metabolism. Our findings illustrate the ability of NMR-based metabolic profiling of immortalised human cells to detect metabolic effects on central metabolism due to toxin exposure. The established data sets will enable more subtle biochemical changes in the HepG2 model cell system to be identified in future toxicity testing.

Effect of traditional Chinese medicine on metabolism disturbance in ischemic heart diseases

ETHNOPHARMACOLOGICAL RELEVANCE

Ischemic heart diseases (IHD), characterized by metabolic dysregulation, contributes majorly to the global morbidity and mortality. Glucose, lipid and amino acid metabolism are critical energy production for cardiomyocytes, and disturbances of these metabolism lead to the cardiac injury. Traditional Chinese medicine (TCM), widely used for treating IHD, have been demonstrated to effectively and safely regulate the cardiac metabolism reprogramming.

AIM OF THE REVIEW

This study discussed and analyzed the disturbed cardiac metabolism induced by IHD and development of formulas, extracts, single herb, bioactive compounds of TCM ameliorating IHD injury via metabolism regulation, with the aim of providing a basis for the development of clinical application of therapeutic strategies for TCM in IHD.

MATERIALS AND METHODS

With "ischemic heart disease", "myocardial infarction", "myocardial ischemia", "metabolomics", "Chinese medicine", "herb", "extracts" "medicinal plants", "glucose", "lipid metabolism", "amino acid" as the main keywords, PubMed, Web of Science, and other online search engines were used for literature retrieval.

RESULTS

IHD exhibits a close association with metabolism disorders, including but not limited to glycolysis, the TCA cycle, oxidative phosphorylation, branched-chain amino acids, fatty acid β-oxidation, ketone body metabolism, sphingolipid and glycerol-phospholipid metabolism. The therapeutic potential of TCM lies in its ability to regulate these disturbed cardiac metabolisms. Additionally, the active ingredients of TCM have depicted wonderful effects in cardiac metabolism reprogramming in IHD.

CONCLUSION

Drawing from the principles of TCM, we have pinpointed specific herbal remedies for the treatment of IHD, and leveraged advanced metabolomics technologies to uncover the effect of these TCMs on metabolomics alteration. In the future, further clinical experimental studies should be included to explore whether more TCM medicines can play a therapeutic role in IHD by reversing cardiac metabolism disorders; multi-omics would be conducted to explore more pathways and genes targeting such metabolism reprogramming by TCMs, and to seek more TCM therapies for IHD.

Unnatural lipids for simultaneous mRNA delivery and metabolic cell labeling

Lipids have demonstrated tremendous promise for mRNA delivery, as evidenced by the success of Covid-19 mRNA vaccines. However, existing lipids are mostly used as delivery vehicles and lack the ability to monitor and further modulate the target cells. Here, for the first time, we report a class of unnatural lipids (azido-DOTAP) that can efficiently deliver mRNAs into cells and meanwhile metabolically label cells with unique chemical tags (e.g., azido groups). The azido tags expressed on the cell membrane enable the monitoring of transfected cells, and can mediate subsequent conjugation of cargos via efficient click chemistry for further modulation of transfected cells. We further demonstrate that the dual-functional unnatural lipid is applicable to different types of cells including dendritic cells, the prominent type of antigen presenting cells, potentially opening a new avenue to developing enhanced mRNA vaccines.

Metabolomics reveals the effects of Lactiplantibacillus plantarum dy-1 fermentation on the lipid-lowering capacity of barley β-glucans in an in vitro model of gut-liver axis

Bioactive polysaccharides known as the biological response modifiers, can directly interact with intestinal epithelium cells (IEC) and regulate key metabolic processes such as lipid metabolism. Here, the coculture of Caco-2/HT29 monolayer (>400 Ω × cm2) and HepG2 cells was developed to mimic the gut-liver interactions. This system was used to investigate the effects of raw and fermented barley β-glucans (RBG and FBG) on lipid metabolism by directly interacting with IEC. Both RBG and FBG significantly and consistently reduced the lipid droplets and triacylglycerol levels in monoculture and coculture of HepG2 overloaded with oleic acid. Notably, FBG significantly and distinctly elevated PPARα (p < 0.05) and PPARα-responsive ACOX-1 (p < 0.01) gene expressions, promoting lipid degradation in cocultured HepG2. Moreover, the metabolomics analyses revealed that FBG had a unique impact on extracellular metabolites, among them, the differential metabolite thiomorpholine 3-carboxylate was significantly and strongly correlated with PPARα (r = -0.68, p < 0.01) and ACOX-1 (r = -0.76, p < 0.01) expression levels. Taken together, our findings suggest that FBG-mediated gut-liver interactions play a key role in its lipid-lowering effects that are superior to those of RBG. These results support the application of Lactiplantibacillus fermentation for improving hypolipidemic outcomes.

Progress of polymer-based strategies in fungal disease management: Designed for different roles

Fungal diseases have posed a great challenge to global health, but have fewer solutions compared to bacterial and viral infections. Development and application of new treatment modalities for fungi are limited by their inherent essential properties as eukaryotes. The microorganism identification and drug sensitivity analyze are limited by their proliferation rates. Moreover, there are currently no vaccines for prevention. Polymer science and related interdisciplinary technologies have revolutionized the field of fungal disease management. To date, numerous advanced polymer-based systems have been developed for management of fungal diseases, including prevention, diagnosis, treatment and monitoring. In this review, we provide an overview of current needs and advances in polymer-based strategies against fungal diseases. We high light various treatment modalities. Delivery systems of antifungal drugs, systems based on polymers' innate antifungal activities, and photodynamic therapies each follow their own mechanisms and unique design clues. We also discuss various prevention strategies including immunization and antifungal medical devices, and further describe point-of-care testing platforms as futuristic diagnostic and monitoring tools. The broad application of polymer-based strategies for both public and personal health management is prospected and integrated systems have become a promising direction. However, there is a gap between experimental studies and clinical translation. In future, well-designed in vivo trials should be conducted to reveal the underlying mechanisms and explore the efficacy as well as biosafety of polymer-based products.

2'-Fucosyllactose Remits Colitis-Induced Liver Oxygen Stress through the Gut-Liver-Metabolites Axis

Liver oxygen stress is one of the main extraintestinal manifestations of colitis and 5% of cases develop into a further liver injury and metabolic disease. 2′-fucosyllactose (2′-FL), a main member of human milk oligosaccharides (HMOs), has been found to exert efficient impacts on remitting colitis. However, whether 2′-FL exerts the function to alleviate colitis-induced liver injury and how 2′-FL influences the metabolism via regulating gut microbiota remain unknown. Herein, in our study, liver oxygen stress was measured by measuring liver weight and oxygen-stress-related indicators. Then, 16S full-length sequencing analysis and non-target metabolome in feces were performed to evaluate the overall responses of metabolites and intestinal bacteria after being treated with 2′-FL (400 mg/kg b.w.) in colitis mice. The results showed that, compared with the control group, the liver weight of colitis mice was significantly decreased by 18.30% (p < 0.05). After 2′-FL treatment, the liver weight was significantly increased by 12.65% compared with colitis mice (p < 0.05). Meanwhile, they exhibited higher levels of oxidation in liver tissue with decreasing total antioxidant capacity (T-AOC) (decreased by 17.15%) and glutathione (GSH) levels (dropped by 22.68%) and an increasing malondialdehyde (MDA) level (increased by 36.24%), and 2′-FL treatment could reverse those tendencies. Full-length 16S rRNA sequencing revealed that there were 39 species/genera differentially enriched in the control, dextran sulphate sodium (DSS), and DSS + 2′-FL groups. After treatment with 2′-FL, the intestinal metabolic patterns, especially glycometabolism and the lipid-metabolism-related process, in DSS mice were strikingly altered with 33 metabolites significantly down-regulated and 26 metabolites up-regulated. Further analysis found DSS induced a 40.01%, 41.12%, 43.81%, and 39.86% decline in acetic acid, propionic acid, butyric acid, and total short chain fatty acids (SCFAs) in colitis mice (all p < 0.05), respectively, while these were up-regulated to different degrees in the DSS + 2′-FL group. By co-analyzing the data of gut microbiota and metabolites, glycometabolism and lipid-metabolism-associated metabolites exhibited strong positive/negative relationships with Akkermansia_muciniphila (all p < 0.01) and Paraprevotella spp. (all p < 0.01), suggesting that the two species might play crucial roles in the process of 2′-FL alleviating colitis-induced liver oxygen stress. In conclusion, in the gut−liver−microbiotas axis, 2′-FL mediated in glucose and lipid-related metabolism and alleviated liver oxygen stress via regulating gut microbiota in the DSS-induced colitis model. The above results provide a new perspective to understand the probiotic function of 2′-FL.

Multi-Dose Intravenous Administration of Neutral and Cationic Liposomes in Mice: An Extensive Toxicity Study

Liposomes are widely used as delivery systems for therapeutic purposes. However, the toxicity associated with the multi-dose administration of these nanoparticles is not fully elucidated. Here, we evaluated the toxicity of the prolonged administration of liposomes composed of neutral or cationic phospholipids often used in drug and gene delivery. For that purpose, adult wild-type mice (C57Bl6) were randomly distributed into three groups receiving either vehicle (PBS), neutral, or cationic liposomes and subjected to repeated intravenous injections for a total of 10 doses administered over 3 weeks. Several parameters, including mortality, body weight, and glucose levels, were monitored throughout the trial. While these variables did not change in the group treated with neutral liposomes, the group treated with the positively charged liposomes displayed a mortality rate of 45% after 10 doses of administration. Additional urinalysis, blood tests, and behavioral assays to evaluate impairments of motor functions or lesions in major organs were also performed. The cationic group showed less forelimb peak force than the control group, alterations at the hematological level, and inflammatory components, unlike the neutral group. Overall, the results demonstrate that cationic liposomes are toxic for multi-dose administration, while the neutral liposomes did not induce changes associated with toxicity. Therefore, our results support the use of the well-known neutral liposomes as safe drug shuttles, even when repetitive administrations are needed.

Metabolomic Analysis Reveals the Mechanisms of Hepatotoxicity Induced by Aflatoxin M1 and Ochratoxin A

Aflatoxin M1 (AFM1) is the only toxin with the maximum residue limit in milk, and ochratoxin A (OTA) represents a common toxin in cereals foods. It is common to find the co-occurrence of these two toxins in the environment. However, the interactive effect of these toxins on hepatoxicity and underlying mechanisms is still unclear. The liver and serum metabolomics in mice exposed to individual AFM1 at 3.5 mg/kg b.w., OTA at 3.5 mg/kg b.w., and their combination for 35 days were conducted based on the UPLC-MS method in the present study. Subsequent metabolome on human hepatocellular liver carcinoma (Hep G2) cells was conducted to narrow down the key metabolites. The phenotypic results on liver weight and serum indicators, such as total bilirubin and glutamyltransferase, showed that the combined toxins had more serious adverse effects than an individual one, indicating that the combined AFM1 and OTA displayed synergistic effects on liver damage. Through the metabolic analysis in liver and serum, we found that (i) a synergistic effect was exerted in the combined toxins, because the number of differentially expressed metabolites on combination treatment was higher than the individual toxins, (ii) OTA played a dominant role in the hepatoxicity induced by the combination of AFM1, and OTA and (iii) lysophosphatidylcholines (LysoPCs), more especially, LysoPC (16:1), were identified as the metabolites most affected by AFM1 and OTA. These findings provided a new insight for identifying the potential biomarkers for the hepatoxicity of AFM1 and OTA.

Salvia miltiorrhiza and the Volatile of Dalbergia odorifera Attenuate Chronic Myocardial Ischemia Injury in a Pig Model: A Metabonomic Approach for the Mechanism Study

Salvia miltiorrhiza (SM) coupled with Dalbergia odorifera (DO) has been used to relieve cardiovascular diseases in China for many years. Our previous studies have integrated that SM—the volatile oil of DO (SM-DOO)—has a cardioprotective effect on chronic myocardial ischemia based on a pharmacological method, but the cardioprotective mechanism has not been elucidated completely in the metabonomic method. In the present study, a metabonomic method based on high-performance liquid chromatography time-of-flight mass spectrometry (HPLC-Q-TOF-MS) was performed to evaluate the effects of SM-DOO on chronic myocardial ischemia induced by an ameroid constrictor, which was placed on the left anterior descending coronary artery (LAD) of pigs. Pigs were divided into three groups: sham, model, and SM-DOO group. With multivariate analysis, a clear cluster among the different groups was obtained and the potential biomarkers were recognized. These biomarkers were mainly related to energy metabolism, glucose metabolism, and fatty acid metabolism. Furthermore, the protein expressions of phosphorylated AMP-activated protein kinase (p-AMPK) and glucose transporter-4 (GLUT4) were significantly upregulated by SM-DOO. The result indicated that SM-DOO could regulate the above biomarkers and metabolic pathways, especially energy metabolism and glucose metabolism. By analyzing and verifying the biomarkers and metabolic pathways, further understanding of the cardioprotective effect of SM-DOO with its mechanism was evaluated. Metabonomic is a reliable system biology approach for understanding the cardioprotective effects of SM-DOO on chronic myocardial ischemia and elucidating the mechanism underlying this protective effect.

Stabilization of liposomes with silicone layer improves their elastomechanical properties while not compromising biological features

The liposomes are among the most promising types of drug delivery systems but low stability significantly limits their application. Some approaches proposed to overcome this drawback may affect the liposomes toxicity profile. It is assumed that developed by us and presented here stabilization method involving formation of silicone network within the liposomal bilayer will improve elastomechanical properties of vesicles while not deteriorating their biocompatibility. The silicone-stabilized liposomes were prepared by base-catalyzed polycondensation process of the 1,3,5,7-tetramethylcyclotetrasiloxane (D₄^H) within the liposomal bilayer. The systematic biological in vitro studies of vesicles obtained were carried out. Moreover, the elastomechanical features investigation employing atomic force microscopy (AFM) measurements was performed. These properties of the liposome membrane are of great importance since they define the nanocarriers' stability as well as play a significant role in their cellular uptake via endocytosis. Applying the Derjaguin-Muller-Toporov (DMT) model, the elastic modulus of the silicone-stabilized liposomes was determined and compared to that characteristic for the pristine liposomes. The in vitro biological evaluation of silicone-stabilized liposomes demonstrated that these vesicles are not toxic for blood cells isolated from healthy donors and they do not induce oxidative stress in HepG2 cells. AFM results confirmed the stabilizing effect of silicone and revealed that the silicone network improves the elastomechanical properties of the resulted liposomes. This is the first report demonstrating that the silicone-stabilized liposomes retain biocompatibility of pristine liposomes' while acquire significantly better elastomechanical features.

Integrative proteomics and metabolomics analysis reveals the toxicity of cationic liposomes to human normal hepatocyte cell line L02

Changes in the expression of proteins and profiles of metabolites in L02 cells were investigated after exposure to CLs based on the iTRAQ and UHPLC-Q-TOF/MS, and proteomics data were coupled with metabolomics data to comprehensively assess the potential toxicity mechanisms of CLs.