Lipid peroxidation products' role in autophagy regulation

Molecular dynamics simulation revealing the interactions between toxic aldehydes and starch: A case study of malondialdehyde, 4-hydroxy-2-hexenal, and 4-hydroxy-2-nonenal in starch-based food during frying

Toxic compounds in fried food products attract increasing attention, but studies regarding the levels of common toxins, such as malondialdehyde (MDA), 4-hydroxy-2-hexenal (4-HHE), and 4-hydroxy-2-nonenal (4-HNE), in fried starch-based food (FSBF) are scarce. Herein, we investigated the formation and distributions of these aldehydes in FSBF, and the frying oil and FSBF retained higher levels of low-molecular-weight aldehydes. The highest aldehyde concentrations were observed in French fries. Simulated frying experiments revealed that the distributions of the toxic aldehydes in FSBF were mainly determined by the amylose content. Molecular dynamics simulations indicated that amylose interacted strongly with 4-HNE, but its interactions with MDA and 4-HHE were weaker. The migration of MDA, 4-HHE, and 4-HNE into FSBFs was primarily attributed to the interactions between the toxic aldehydes and amylose. This study should provide a novel basis for the control and elimination of toxic aldehydes in fried food.

Triple regulation of oxidative-acetylation cycling pathways in COPD glucocorticoid resistance by HuaTanJiangQi capsules

Glucocorticoid (GC) resistance in chronic obstructive pulmonary disease (COPD) induced by long-term smoking, significantly reduces the quality of life of patients. The complex interaction between antioxidants and acetylation is an important factor that contributes to the slow progression of treatment. This study highlights the development of GC resistance in COPD through 4-hydroxynonenal (4-HNE), multidrug resistance-associated protein 1 (MRP1), histone deacetylase 2 (HDAC2), and nuclear related factor 2 (Nrf2), using enzyme-linked immunosorbent assays, western blotting, and siRNA silencing. Our results suggest that long-term exposure to cigarette smoke can increase 4-HNE toxicity via reactive oxygen species (ROS)-induced lipid peroxidation and decrease the expression of MRP1, histone HDAC2, and Nrf2. Together, these molecules form and enhance the cyclic resistance pathway in COPD, including MRP1 reducing 4-HNE efflux, 4-HNE down-regulating HDAC2 expression by oxidation, HDAC2 reducing Nrf2 transcription by deacetylation, and Nrf2 reducing MRP1 expression through acetylation. The HuaTanJiangQi Capsule (HTJQ) reduces GC resistance via a triple regulatory pathway by enhancing the activity of HDAC2, promoting the transcription of Nrf2, up-regulating the expression of MRP1, and reducing lipid peroxidation induced by ROS. Thus, this cyclic mechanism of GC resistance in COPD may open new avenues for robust therapies using HTJQ.

Exploring the effect of chlorogenic acid on oxidative stress and autophagy in dry eye mice via the AMPK/ULK1 pathway

Dry eye disease (DED) is closely associated with oxidative stress (OS); its high prevalence and the limitations of current treatments highlight the need for highly effective antioxidants. Chlorogenic acid (CGA) can upregulate the activity of antioxidant enzymes, hinder the process of lipid peroxidation, and exert potent antioxidant effects. In this study, we established an OS-induced DED mouse model to investigate the protective effect and mechanism of CGA against OS-induced DED. Three aspects were examined: oxidative damage, apoptosis, and autophagy. The results demonstrated that CGA improved ocular surface signs in DED mice, decreased inflammatory responses in the meibomian gland (MG), downregulated levels of reactive oxygen species (ROS) and malondialdehyde (MDA), inhibited apoptosis and autophagy, and regulated proteins related to the AMPK (AMP-activated protein kinase)/ULK1 (UNC-51-like Kinase 1) signaling pathway in the MG of DED mice. These findings suggest that CGA can attenuate oxidative damage and inhibit related apoptosis and autophagy in the MG of DED mice by affecting the expression of proteins related to the AMPK/ULK1 signaling pathway.

Lipid Coating Modulates Effects of Nanoceria on Oxidative Metabolism in Human Embryonic Lung Fibroblasts: A Case of Cardiolipin

The unique redox properties of nanoscale cerium dioxide determine its diverse application in biology and medicine as a regulator of oxidative metabolism. Lipid modifiers of the nanoparticle surface change their biochemical properties and bioavailability. Complexes with lipids can be formed upon contact of the nanoparticles with the membrane. The effects of lipid coating on nanoceria have not been studied yet. Here, we assessed the effect of bare and cardiolipin-coated CeO2 on the expression of oxidative metabolism genes in human embryonic lung fibroblasts. Cell viability, mitochondrial activity, intracellular reactive oxygen species, NOX4, NRF2, and NF-κB expression, oxidative DNA damage/repair, autophagy, and cell proliferation were studied. We used an MTT assay, fluorescence microscopy, real-time reverse transcription polymerase chain reaction, and flow cytometry. At a concentration of 1.5 μM, bare and cardiolipin-coated nanoceria penetrated into cells within 1-3 h. Cell survival, mitochondrial activity, and the proliferative effect were similar for bare and cardiolipin-coated nanoceria. Intracellular ROS, activation of NOX4, NRF2, and NF-kB, DNA oxidative damage, and DNA break/repair were different. Cardiolipin-coated nanoceria induced intracellular oxidative stress and short-term activation of these genes and DNA damage/break/repair. Unlike bare nanoceria, cardiolipin-coated nanoceria induced autophagy. Thus, the effects of cardiolipin-coated nanoceria are determined by both the nanoceria itself and cardiolipin. Presumably, the differences in properties are due to lipid peroxidation of cardiolipin. This effect needs to be taken into account when developing nanoceria-based drugs targeting mitochondria.

How lipids, as important endogenous nutrient components, affect the quality of aquatic products: An overview of lipid peroxidation and the interaction with proteins

As the global population continues to grow and the pressure on livestock and poultry supply increases, the oceans have become an increasingly important source of quality food for future generations. However, nutrient-rich aquatic product is susceptible to lipid oxidation during storage and transport, reducing its nutritional value and increasing safety risks. Therefore, identifying the specific effects of lipid oxidation on aquatic products has become particularly critical. At the same time, some lipid oxidation products have been found to interact with aquatic product proteins in various ways, posing a safety risk. This paper provides an in-depth exploration of the pathways, specific effects, and hazards of lipid oxidation in aquatic products, with a particular focus on the interaction of lipid oxidation products with proteins. Additionally, it discusses the impact of non-thermal treatment techniques on lipids in aquatic products and examines the application of natural antioxidants in aquatic products. Future research endeavors should delve into the interactions between lipids and proteins in these products and their specific effects to mitigate the impact of non-thermal treatment techniques on lipids, thereby enhancing the safety of aquatic products and ensuring food safety for future generations.

Emerging mechanisms of lipid peroxidation in regulated cell death and its physiological implications

Regulated cell death (RCD) refers to the form of cell death that can be regulated by various biomacromolecules. Each cell death modalities have their distinct morphological changes and molecular mechanisms. However, intense evidences suggest that lipid peroxidation can be the common feature that initiates and propagates the cell death. Excessive lipid peroxidation alters the property of membrane and further damage the proteins and nucleic acids, which is implicated in various human pathologies. Here, we firstly review the classical chain process of lipid peroxidation, and further clarify the current understanding of the myriad roles and molecular mechanisms of lipid peroxidation in various RCD types. We also discuss how lipid peroxidation involves in diseases and how such intimate association between lipid peroxidation-driven cell death and diseases can be leveraged to develop rational therapeutic strategies.

The activation of autophagy by molecular hydrogen is functionally associated with osmotic tolerance in Arabidopsis

The role of molecular hydrogen (H2) in autophagy during inflammatory response is controversial in mammalian cells. Although the stimulation of H2 production in response to osmotic stress was observed in plants, its synthetic pathway and the interrelationship between its induction and plant autophagy remain unclear. Here, the induction of autophagy was observed in Arabidopsis upon osmotic stress, assessing by the autophagosome formation and autophagy-related genes expression. Above responses were intensified by H2 fumigation. Meanwhile, the reduction in seedling growth and roots vigor was obviously abolished, accompanied by reestablishing redox balance. These H2 responses were markedly impaired in T-DNA knockout lines atg2, atg5, and atg18. Further evidence showed that the increased endogenous H2 synthesis by genetic manipulation, not only stimulated autophagosome formation, but also triggered various plant responses toward osmotic stress. By contrast, these responses were obviously abolished by the disruption of endogenous H2 synthesis with the addition of 2,6-dichloroindophenol sodium salt. Together, the integrated genetic and molecular evidence clearly illustrated the requirement of autophagy activation in H2 control of plant osmotic tolerance.

Photosynthetic ROS and retrograde signaling pathways

Sessile plants harness mitochondria and chloroplasts to sense and adapt to diverse environmental stimuli. These complex processes involve the generation of pivotal signaling molecules, including reactive oxygen species (ROS), phytohormones, volatiles, and diverse metabolites. Furthermore, the specific modulation of chloroplast proteins, through activation or deactivation, significantly enhances the plant's capacity to engage with its dynamic surroundings. While existing reviews have extensively covered the role of plastidial retrograde modules in developmental and light signaling, our focus lies in investigating how chloroplasts leverage photosynthetic ROS to navigate environmental fluctuations and counteract oxidative stress, thereby sustaining primary metabolism. Unraveling the nuanced interplay between photosynthetic ROS and plant stress responses holds promise for uncovering new insights that could reinforce stress resistance and optimize net photosynthesis rates. This exploration aspires to pave the way for innovative strategies to enhance plant resilience and agricultural productivity amidst changing environmental conditions.

6-Gingerol improves lipid metabolism disorders in skeletal muscle by regulating AdipoR1/AMPK signaling pathway

BACKGROUND

To delve into the precise mechanisms by which 6-gingerol ameliorates lipid metabolism disorders in skeletal muscle.

METHODS

The level of triglycerides (TG) was used to evaluate lipid deposition. In skeletal muscle, transmission electron microscopy (TEM) was employed to observe mitochondrial morphology. Additionally, PCR was applied to detect mitochondrial biogenesis, and levels of malondialdehyde (MDA), catalase (CAT), glutathione, r-glutamyl cysteingl+glycine (GSH) and nicotinamide adenine dinucleotide (NADH) were measured to assess mitochondrial oxidative stress levels. In vivo, flow cytometry and immunofluorescence assays were conducted to quantify reactive oxygen species (ROS) and mitochondrial membrane potential (MMP). Furthermore, the Seahorse XF assays was utilized to assess mitochondrial respiratory capacity. Fluorescence confocal microscopy and molecular docking were applied to analyze the binding of 6-gingerol and adiponectin receptor 1 (AdipoR1). The expression of AdipoR1, AMPK, PGC-1α and SIRT1 were detected by Western Blot.

RESULTS

In vivo, 6-gingerol could reduce body weight in mice induced by a high-fat diet, enhance metabolic profiles in plasma, decrease lipid accumulation in skeletal muscle and liver, and elevate adiponectin levels. In skeletal muscle, it could restore mitochondrial morphology, boost mitochondrial copy number and biogenesis, and mitigate oxidative stress. In vitro, 6-gingerol may directly interact with AdipoR1 to upregulate the expression of downstream proteins p-AMPK, SIRT1, and PGC-1α, leading to a reduction in lipid deposition, a decrease in ROS production, an increase in mitochondrial membrane potential, and an enhancement of mitochondrial respiratory capacity in C2C12 myotubes.

CONCLUSION

6-Gingerol ameliorated lipid metabolism in skeletal muscle by regulating the AdipoR1/AMPK signaling pathway.

Salivary Metabolites in Breast Cancer and Fibroadenomas: Focus on Menopausal Status and BMI

This study of the features of the biochemical composition of biological fluids in patients with breast cancer, including saliva, allows us to identify some indicators as metabolic predictors of the presence of the disease.

OBJECTIVES

to study the influence of the menopause factor and body mass index (BMI) on the biochemical composition of saliva and to evaluate the applicability of metabolic markers of saliva for the diagnosis of breast cancer.

METHODS

The case-control study involved 1438 people (breast cancer, n = 543; fibroadenomas, n = 597; control, n = 298). A comprehensive study of the biochemical composition of saliva was carried out using 36 parameters.

RESULTS

When comparing the salivary biochemical composition in breast cancer, fibroadenomas, and controls, it is necessary to take into account the menopausal status, as well as BMI (less than 25 or more) for the group of patients with preserved menstrual function. A complex of biochemical parameters has been identified that change in saliva during breast cancer, regardless of menopause and BMI (total protein, urea, uric acid, NO, α-amino acids, GGT), as well as specific parameters that must be taken into account when analyzing individual subgroups (imidazole compounds, LDH, catalase, α-amylase). During the study of a separate group of patients with leaf-shaped (phyllodes) tumors, we found similarities with breast cancer in the changes in some biochemical parameters that can be attributed to metabolites of malignant growth (protein, α-amino acids, calcium, NO, pyruvate, peroxidase, α-amylase).

CONCLUSIONS

We demonstrated changes in a wide range of salivary biochemical parameters depending on the presence of fibroadenomas and breast cancer. From the point of view of clinical practice, this may be useful information for monitoring the condition of patients with fibroadenomas, which are difficult to unambiguously classify based on instrumental diagnostics alone.

Protective effect of 5,4'-dihydroxy-6,8-dimethoxy7-O-rhamnosylflavone from Indigofera aspalathoides Vahl on lipopolysaccharide-induced intestinal injury in mice

Intestinal inflammation is one of the main health challenges affecting the quality of life of millions of people worldwide. Accumulating evidence introduces several flavonoids with multifaceted therapeutic properties in inflammatory diseases including intestinal inflammation. Herein, we examined potential anti-inflammatory properties of 5,4'-dihydroxy-6,8-dimethoxy7-O-rhamnosylflavone (DDR) flavone derived from Indigofera aspalathoides Vahl (I. aspalathoides Vahl) on lipopolysaccharide (LPS)-induced intestinal inflammation and injury in mice. Oral DDR treatment decreased serum levels of pro-inflammatory cytokines including TNF-α, IL-6, and IL-1β. It reduced oxidative stress through augmenting the activities of catalase (CAT) and superoxide dismutase (SOD) and reducing the level of malondialdehyde (MDA) in the duodenum and colon tissues. Moreover, DDR enhanced the activities of digestive enzymes including trypsin, pancreatic lipase, and amylase, and increased the production of short-chain fatty acids (SCFAs) by colon microbiota. Histopathological investigation of duodenum and colon revealed that DDR inhibited inflammatory infiltration and largely restored mucosal architecture and protected lining integrity. Importantly, DDR suppressed activation of nuclear factor-κB (NF-κB) signaling pathway through reduced expression of Toll-like receptor 4 (TLR4) and expression and phosphorylation of P65. The current study identified DDR as anti-inflammatory flavonoid capable of ameliorating LPS-induced intestinal inflammation through suppression of NF-κB signaling.

Docosahexaenoic Acid Coordinating with Sodium Selenite Promotes Paraptosis in Colorectal Cancer Cells by Disrupting the Redox Homeostasis and Activating the MAPK Pathway

Tumor cells are characterized by a delicate balance between elevated oxidative stress and enhanced antioxidant capacity. This intricate equilibrium, maintained within a threshold known as redox homeostasis, offers a unique perspective for cancer treatment by modulating reactive oxygen species (ROS) levels beyond cellular tolerability, thereby disrupting this balance. However, currently used chemotherapy drugs require larger doses to increase ROS levels beyond the redox homeostasis threshold, which may cause serious side effects. How to disrupt redox homeostasis in cancer cells more effectively remains a challenge. In this study, we found that sodium selenite and docosahexaenoic acid (DHA), a polyunsaturated fatty acid extracted from marine fish, synergistically induced cytotoxic effects in colorectal cancer (CRC) cells. Physiological doses of DHA simultaneously upregulated oxidation and antioxidant levels within the threshold range without affecting cell viability. However, it rendered the cells more susceptible to reaching the upper limit of the threshold of redox homeostasis, facilitating the elevation of ROS levels beyond the threshold by combining with low doses of sodium selenite, thereby disrupting redox homeostasis and inducing MAPK-mediated paraptosis. This study highlights the synergistic anticancer effects of sodium selenite and DHA, which induce paraptosis by disrupting redox homeostasis in tumor cells. These findings offer a novel strategy for more targeted and less toxic cancer therapies for colorectal cancer treatment.

Nanomaterials in crossroad of autophagy control in human cancers: Amplification of cell death mechanisms

Cancer is the result of genetic abnormalities that cause normal cells to grow into neoplastic cells. Cancer is characterized by several distinct features, such as uncontrolled cell growth, extensive spreading to other parts of the body, and the ability to resist treatment. The scientists have stressed the development of nanostructures as novel therapeutic options in suppressing cancer, in response to the emergence of resistance to standard medicines. One of the specific mechanisms with dysregulation during cancer is autophagy. Nanomaterials have the ability to specifically carry medications and genes, and they can also enhance the responsiveness of tumor cells to standard therapy while promoting drug sensitivity. The primary mechanism in this process relies on autophagosomes and their fusion with lysosomes to break down the components of the cytoplasm. While autophagy was initially described as a form of cellular demise, it has been demonstrated to play a crucial role in controlling metastasis, proliferation, and treatment resistance in human malignancies. The pharmacokinetic profile of autophagy modulators is poor, despite their development for use in cancer therapy. Consequently, nanoparticles have been developed for the purpose of delivering medications and autophagy modulators selectively and specifically to the cancer process. Furthermore, several categories of nanoparticles have demonstrated the ability to regulate autophagy, which plays a crucial role in defining the biological characteristics and response to therapy of tumor cells.

Regulation of P-Glycoprotein during Oxidative Stress

P-glycoprotein (Pgp, ABCB1, MDR1) is an efflux transporter protein that removes molecules from the cells (outflow) into the extracellular space. Pgp plays an important role in pharmacokinetics, ensuring the absorption, distribution, and excretion of drugs and its substrates, as well as in the transport of endogenous molecules (steroid and thyroid hormones). It also contributes to tumor cell resistance to chemotherapy. In this review, we summarize the mechanisms of Pgp regulation during oxidative stress. The currently available data suggest that Pgp has a complex variety of regulatory mechanisms under oxidative stress, involving many transcription factors, the main ones being Nrf2 and Nf-kB. These factors often overlap, and some can be activated under certain conditions, such as the deposition of oxidation products, depending on the severity of oxidative stress. In most cases, the expression of Pgp increases due to increased transcription and translation, but under severe oxidative stress, it can also decrease due to the oxidation of amino acids in its molecule. At the same time, Pgp acts as a protector against oxidative stress, eliminating the causative factors and removing its by-products, as well as participating in signaling pathways.