Lipocalin 2 regulates mitochondrial phospholipidome remodeling, dynamics, and function in brown adipose tissue in male mice.

Mitochondrial function is vital for energy metabolism in thermogenic adipocytes. Impaired mitochondrial bioenergetics in brown adipocytes are linked to disrupted thermogenesis and energy balance in obesity and aging. Phospholipid cardiolipin (CL) and phosphatidic acid (PA) jointly regulate mitochondrial membrane architecture and dynamics, with mitochondria-associated endoplasmic reticulum membranes (MAMs) serving as the platform for phospholipid biosynthesis and metabolism. However, little is known about the regulators of MAM phospholipid metabolism and their connection to mitochondrial function. We discover that LCN2 is a PA binding protein recruited to the MAM during inflammation and metabolic stimulation. Lcn2 deficiency disrupts mitochondrial fusion-fission balance and alters the acyl-chain composition of mitochondrial phospholipids in brown adipose tissue (BAT) of male mice. Lcn2 KO male mice exhibit an increase in the levels of CLs containing long-chain polyunsaturated fatty acids (LC-PUFA), a decrease in CLs containing monounsaturated fatty acids, resulting in mitochondrial dysfunction. This dysfunction triggers compensatory activation of peroxisomal function and the biosynthesis of LC-PUFA-containing plasmalogens in BAT. Additionally, Lcn2 deficiency alters PA production, correlating with changes in PA-regulated phospholipid-metabolizing enzymes and the mTOR signaling pathway. In conclusion, LCN2 plays a critical role in the acyl-chain remodeling of phospholipids and mitochondrial bioenergetics by regulating PA production and its function in activating signaling pathways.

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"Let food be thy medicine and medicine be thy food"-the ancient adage proposed by Greek philosopher Hippocrates of Kos thousands of years ago already acknowledged the importance of the beneficial and health-promoting effects of food nutrients on the body (Mafra et al., 2021). Recent epidemiological and large-scale community studies have also reported that unhealthy diets or eating habits may contribute heavily to the burden of chronic, non-communicable diseases, such as obesity, type 2 diabetes mellitus (T2DM), hypertension, cardiovascular disease (CVD), cancer, neurodegenerative diseases, arthritis, chronic kidney disease (CKD), and chronic obstructive pulmonary disease (COPD) (Jayedi et al., 2020; Gao et al., 2022). Emerging evidence highlights that a diet rich in fruits and vegetables can prevent various chronic diseases (Chen et al., 2022). Food bioactive compounds including vitamins, phytochemicals, and dietary fibers are responsible for these nutraceutical benefits (Boeing et al., 2012). Recently, phytochemicals such as polyphenols, phytosterols, and carotenoids have gained increasing attention due to their potential health benefits to alleviate chronic diseases (van Breda and de Kok, 2018). Understanding the role of phytochemicals in health promotion and preventing chronic diseases can inform dietary recommendations and the development of functional foods. Therefore, it is crucial to investigate the health benefits of phytochemicals derived from commonly consumed foods for the prevention and management of chronic diseases.

Malvidin-3-O-Glucoside from Blueberry Ameliorates Nonalcoholic Fatty Liver Disease by Regulating Transcription Factor EB-Mediated Lysosomal Function and Activating the Nrf2/ARE Signaling Pathway.

Nonalcoholic fatty liver disease (NAFLD) has become a universal health issue, whereas there is still a lack of widely accepted therapy until now. Clinical research studies have shown that blueberry could effectively regulate the lipid metabolism, thereby improving obesity-related metabolic syndromes; however, the specific active substances and mechanisms remain unclear. Herein, the effects of the major 10 kinds of anthocyanins from blueberry against NAFLD were investigated using an free fatty acid (FFA)-induced cell model. Among these anthocyanins, malvidin-3-O-glucoside (M3G) and malvidin-3-O-galactoside (M3Ga) could remarkably ameliorate FFA-induced lipid accumulation. Besides, M3G and M3Ga also inhibited oxidative stress via suppressing reactive oxygen species and superoxide anion overproduction, increasing glutathione levels, and enhancing activities of antioxidant enzymes. Further studies unveiled that the representative anthocyanin M3G-upregulated transcription factor EB (TFEB)-mediated lysosomal function possibly interacted with TFEB and activated the Nrf2/ARE (antioxidant responsive element) signaling pathway. Overall, this study enriched the knowledge about the health-promoting effects of blueberry anthocyanins against NAFLD and provided ideas for the development of functional foods of blueberry anthocyanins.

Andrographolide Exerts Antihyperglycemic Effect through Strengthening Intestinal Barrier Function and Increasing Microbial Composition of Akkermansia muciniphila.

Accumulating evidence indicates that type 2 diabetes (T2D) is associated with intestinal barrier dysfunction and dysbiosis, implying the potential targets for T2D therapeutics. Andrographolide was reported to have several beneficial effects on diabetes and its associated complications. However, the protective role of andrographolide, as well as its underlying mechanism against T2D, remains elusive. Herein, we reported that andrographolide enhanced intestinal barrier integrity in LPS-induced Caco-2 cells as indicated by the improvement of cell monolayer barrier permeability and upregulation of tight junction protein expression. In addition, andrographolide alleviated LPS-induced oxidative stress by preventing ROS and superoxide anion radical overproduction and reversing glutathione depletion. In line with the in vitro results, andrographolide reduced metabolic endotoxemia and strengthened gut barrier integrity in db/db diabetic mice. We also found that andrographolide appeared to ameliorate glucose intolerance and insulin resistance and attenuated diabetes-associated redox disturbance and inflammation. Furthermore, our results indicated that andrographolide modified gut microbiota composition as indicated by elevated Bacteroidetes/Firmicutes ratio, enriched microbial species of Akkermansia muciniphila, and increased SCFAs level. Taken together, this study demonstrated that andrographolide exerted a glucose-lowering effect through strengthening intestinal barrier function and increasing the microbial species of A. muciniphila, which illuminates a plausible approach to prevent T2D by regulating gut barrier integrity and shaping intestinal microbiota composition.

Structure-based design of human pancreatic amylase inhibitors from the natural anthocyanin database for type 2 diabetes.

Human Pancreatic Amylase (HPA) is an important target for prevention and treatment of type 2 diabetes. Acarbose is a currently available drug acting as a HPA inhibitor, but its gastrointestinal side-effects cannot be neglected. Thus, developing novel HPA inhibitors with no side-effects is of great importance. Herein, we adopted a structure-based design approach and discovered a potent HPA inhibitor, malvidin 3-O-arabinoside (M3A), from the natural anthocyanin database. We identified M3A as an effective HPA inhibitor through virtual screening, enzyme activity and enzyme kinetic assays. We reported the structure and activity relationships as both the anthocyanidin core and glucosyl group affected the HPA inhibitory effect of anthocyanins. Molecular dynamics studies indicated that the HPA inhibition of M3A occurred via its binding to the HPA key catalytic residues Arg195 and Asp197 through stable hydrogen bonding. In addition, M3A was found to reduce α-helix fractions and increase ß-sheet fractions in CD spectrometry. Further in vivo studies showed that M3A significantly ameliorated the postprandial blood glucose level. Taken together, our results provide new insights into the development of novel HPA inhibitors from natural sources as food supplements for type 2 diabetes.

Pelargonidin-3-O-glucoside Derived from Wild Raspberry Exerts Antihyperglycemic Effect by Inducing Autophagy and Modulating Gut Microbiota.

Increasing evidence indicates that anthocyanins exert beneficial effects on type 2 diabetes (T2D), but the underlying mechanism remains unclear. Herein, the hyperglycemia-lowering effect of Pg3G derived from wild raspberry was investigated on high-glucose/high-fat (HG+HF)-induced hepatocytes and db/db diabetic mice. Our results indicated that Pg3G promoted glucose uptake in HG+HF-induced hepatocytes. Moreover, Pg3G induced autophagy, whereas autophagy inhibitors blocked the hypoglycemic effect of Pg3G. Transcriptional factor EB (TFEB) was found to be linked to Pg3G-induced autophagy. In vivo study showed that Pg3G treatment contributed to the improvement of glucose tolerance, insulin sensitivity, and induction of autophagy. Furthermore, Pg3G not only modified the gut microbiota composition, as indicated by an increased abundance of Prevotella, and elevated Bacteroidetes/Firmicutes ratio, but also strengthened the intestinal barrier integrity. This study unveils a novel mechanism that Pg3G attenuates hyperglycemia through inducing autophagy and modulating gut microbiota, which implicates a potential nutritional intervention strategy for T2D.

Polysaccharide from Mulberry Fruit (Morus alba L.) Protects against Palmitic-Acid-Induced Hepatocyte Lipotoxicity by Activating the Nrf2/ARE Signaling Pathway.

This study was aimed to investigate the protective effects of three different mulberry fruit polysaccharide fractions (MFP-I, MFP-II, and MFP-III) against palmitic acid (PA)-induced hepatocyte lipotoxicity and characterize the functional polysaccharide fraction using gel permeation chromatography, high-performance liquid chromatography, Fourier transform infrared spectroscopy, and nuclear magnetic resonance analyses. MFP-I, MFP-II, and MFP-III were isolated from mulberry fruit by stepwise precipitation with 30, 60, and 90% ethanol, respectively. MFP-II at 0.1 and 0.2 mg/mL dramatically attenuated PA-induced hepatic lipotoxicity, while MFP-I and MFP-III showed weak protection. It was demonstrated that MFP-II not only increased nuclear factor erythroid-2-related factor 2 (Nrf2) phosphorylation and its nuclear translocation, thereby activating the Nrf2/ARE signaling pathway, but also enhanced heme oxygenase 1, NAD(P)H:quinone oxidoreductase 1, and γ-glutamate cysteine ligase gene expressions and promoted catalase and glutathione peroxidase activities, which protected hepatocytes against PA-induced oxidative stress and lipotoxicity. Further investigation indicated that the molecular weight of MFP-II was 115.0 kDa, and MFP-II mainly consisted of galactose (30.5%), arabinose (26.2%), and rhamnose (23.1%). Overall, our research might provide in-depth insight into mulberry fruit polysaccharide in ameliorating lipid metabolic disorders.

Procyanidin B2 ameliorates free fatty acids-induced hepatic steatosis through regulating TFEB-mediated lysosomal pathway and redox state.

Procyanidin B2, a naturally occurring phenolic compound, has been reported to exert multiple beneficial functions. However, the effect of procyanidin B2 on free fatty acids (FFAs)-induced hepatic steatosis remains obscure. The present study is therefore aimed to elucidate the protective effect of procyanidin B2 against hepatic steatosis and its underlying mechanism. Herein, we reported that procyanidin B2 attenuated FFAs-induced lipid accumulation and its associated oxidative stress by scavenging excessive ROS and superoxide anion radicals, blocking loss of mitochondrial membrane potential, restoring glutathione content, and increasing activity of antioxidant enzymes (GPx, SOD and CAT) in hepatocytes. Procyanidin B2 mechanistically promoted lipid degradation via modulation of transcription factor EB (TFEB), a master regulator of lysosomal pathway. Molecular docking analysis indicated a possible ligand-binding position of procyanidin B2 with TFEB. In addition, administration of procyanidin B2 resulted in a significant reduction of hepatic fat accumulation in high-fat diet (HFD)-induced obese mice, and also ameliorated HFD-induced metabolic abnormalities, including hyperlipidemia and hyperglycemia. It was confirmed that procyanidin B2 prevented HFD-induced hepatic fat accumulation through down-regulating lipogenesis-related gene expressions (PPARγ, C/EBPα and SREBP-1c), inhibiting pro-inflammatory cytokines production (IL-6 and TNF-α) and increasing antioxidant enzymes activity (GPx, SOD and CAT). Moreover, hepatic fatty acids analysis indicated that procyanidin B2 caused a significant increase in the levels of palmitic acid, oleic acid and linoleic acid. Intriguingly, procyanidin B2 restored the decreased nuclear TFEB expression in HFD-induced liver steatosis and up-regulated its target genes involved in lysosomal pathway (Lamp1, Mcoln, Uvrag), which suggested a previously unrecognized mechanism of procyanidin B2 on ameliorating HFD-induced hepatic steatosis. Taken together, our results demonstrated that procyanidin B2 attenuated FFAs-induced hepatic steatosis through regulating TFEB-mediated lysosomal pathway and redox state, which had important implications that modulation of TFEB might be a potential therapeutic strategy for hepatic steatosis and procyanidin B2 could represent a promising novel agent in the prevention and treatment of non-alcoholic fatty liver disease (NAFLD).

Ethyl carbamate: An emerging food and environmental toxicant.

Ethyl carbamate (EC), a chemical substance widely present in fermented food products and alcoholic beverages, has been classified as a Group 2A carcinogen by the International Agency for Research on Cancer (IARC). New evidence indicates that long-term exposure to EC may cause neurological disorders. Formation of EC in food and its metabolism have therefore been studied extensively and analytical methods for EC in various food matrices have been established. Due to the potential threat of EC to human health, mitigation strategies for EC in food products by physical, chemical, enzymatic, and genetic engineering methods have been developed. Natural products are suggested to provide protection against EC-induced toxicity through the modulation of oxidative stress. This review summarizes knowledge on the formation and metabolism of EC, detection of EC in food products, toxic effects of EC on various organs, and mitigation strategies including prevention of EC-induced tumorigenesis and genotoxicity by natural products.

In vitro gastrointestinal digestion promotes the protective effect of blackberry extract against acrylamide-induced oxidative stress.

Acrylamide (AA)-induced toxicity has been associated with accumulation of excessive reactive oxygen species. The present study was therefore undertaken to investigate the protective effect of blackberry digests produced after (BBD) in vitro gastrointestinal (GI) digestion against AA-induced oxidative damage. The results indicated that the BBD (0.5 mg/mL) pretreatment significantly suppressed AA-induced intracellular ROS generation (56.6 ± 2.9% of AA treatment), mitochondrial membrane potential (MMP) decrease (297 ± 18% of AA treatment) and glutathione (GSH) depletion (307 ± 23% of AA treatment), thereby ameliorating cytotoxicity. Furthermore, LC/MS/MS analysis identified eight phenolic compounds with high contents in BBD, including ellagic acid, ellagic acid pentoside, ellagic acid glucuronoside, methyl-ellagic acid pentoside, methyl-ellagic acid glucuronoside, cyanidin glucoside, gallic acid and galloyl esters, as primary active compounds responsible for antioxidant action. Collectively, our study uncovered that the protective effect of blackberry was reserved after gastrointestinal digestion in combating exogenous pollutant-induced oxidative stress.

Blackberry subjected to in vitro gastrointestinal digestion affords protection against Ethyl Carbamate-induced cytotoxicity.

Ethyl Carbamate (EC) was detected in many fermented foods. Previous studies indicated that frequent exposure to ethyl carbamate may increase the risk to suffer from cancers. Blackberry is rich in polyphenols and possesses potent antioxidant activity. This study aims to investigate the protective effect of blackberry homogenates produced before (BH) and after in vitro simulated gastrointestinal digestion (BD) on EC-induced toxicity in Caco-2 cells. Our results showed that blackberry homogenates after digestion (BD) was more effective than that before digestion (BH) in ameliorating EC-induced toxicity in Caco-2 cells. Further investigation revealed that BD remarkably attenuated EC-induced toxicity through restoring mitochondrial function, inhibiting glutathione depletion and decreasing overproduction of intracellular reactive oxygen species. Additionally, LC-MS result implied that the better protective capacity of BD may be related to the increased content of two anthocyanins (cyanidin-3-glucoside and cyanidin-3-dioxalyglucoside). Overall, the present study may give implication to prevent EC-induced health problem.

Myricetin protects against diet-induced obesity and ameliorates oxidative stress in C57BL/6 mice.

BACKGROUND: Myricetin is a naturally occurring antioxidant commonly found in various plants. However, little information is available with respect to its direct anti-obesity effects. OBJECTIVE: This study was undertaken to investigate the effect of myricetin on high-fat diet (HFD)-induced obesity in C57BL/6 mice. RESULTS: Administration of myricetin dramatically reduced the body weight of diet-induced obese mice compared with solely HFD-induced mice. Several parameters related to obesity including serum glucose, triglyceride, and cholesterol were significantly decreased in myricetin-treated mice. Moreover, obesity-associated oxidative stress (glutathione peroxidase (GPX) activity, total antioxidant capacity (T-AOC), and malondialdehyde (MDA)) and inflammation (tumor necrosis factor-α (TNF-α)) were ameliorated in myricetin-treated mice. Further investigation revealed that the protective effect of myricetin against HFD-induced obesity in mice appeared to be partially mediated through the down-regulation of mRNA expression of adipogenic transcription factors peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer-binding protein α (C/EBPα), and lipogenic transcription factor sterol regulatory element-binding protein 1c (SREBP-1c). CONCLUSIONS: Consumption of myricetin may help to prevent obesity and obesity-related metabolic complications.

Andrographolide suppresses preadipocytes proliferation through glutathione antioxidant systems abrogation.

AIMS: Oxidative stress is considered to play a profound role in lipid storage and whole-body energy homeostasis. Inhibition of preadipocytes proliferation by natural products is one of the strategies to prevent obesity. Andrographolide, a small molecule, has been reported to possess versatile bioactivities. However, molecular mechanism underlying the potential effect of andrographolide on preadipocytes proliferation remains obscure. MAIN METHODS: In the present study, 3T3-L1 preadipocytes were employed to determine whether andrographolide could affect the proliferation of preadipocytes. KEY FINDINGS: Our results demonstrated andrographolide suppressed 3T3-L1 preadipocytes proliferation. The casual relationship analysis indicated that andrographolide (10 and 20µg/ml) appeared to exert the proliferation inhibitory effect through suppression of glutathione peroxidase 1 (GPX1) activity and depleting GSH by promoting its efflux in 3T3-L1 preadipocytes, which subsequently resulted in 2.06-2.41 fold increase in ROS accumulation. Excessive ROS eruption could account for oxidative damage to mitochondrial membranes as well as ultimately inhibition of cell proliferation. SIGNIFICANCE: Taken together, our study reveals that suppression of GPX1 and GSH depletion by andrographolide seems to play a critical role in the inhibition of 3T3-L1 preadipocytes proliferation, which might have implication for obesity prevention and treatment.

Protective effect of wild raspberry (Rubus hirsutus Thunb.) extract against acrylamide-induced oxidative damage is potentiated after simulated gastrointestinal digestion.

Raspberry is well known as rich source of antioxidants, such as polyphenols and flavonoids. However, after consumption, the antioxidants are subjected to digestive conditions within the gastrointestinal tract that may result in structural and functional alterations. Our previous study indicated that acrylamide (AA)-induced cytotoxicity was associated with oxidative stress. However, the protective effect of wild raspberry extract produced before and after in vitro gastrointestinal digestion against AA-induced oxidative damage is unclear. In the present study, we found that wild raspberry extract produced after digestion (RD) had a pronounced protective effect against AA-induced cytotoxicity compared with that produced before digestion (RE). Further investigation indicated that RD significantly inhibited AA-induced intracellular reactive oxygen species (ROS) generation, mitochondrial membrane potential (MMP) collapse and glutathione (GSH) depletion. Moreover, LC-MS analysis revealed that wild raspberry underwent gastrointestinal digestion significantly increased the contents of esculin, kaempferol hexoside and pelargonidin hexoside.

Hispidin derived from Phellinus linteus affords protection against acrylamide-induced oxidative stress in Caco-2 cells.

Acrylamide (AA), a well-known toxicant, has attracted numerous attentions for its presumably carcinogenesis, neurotoxicity and cytotoxicity. Oxidative stress was considered to be associated with acrylamide cytotoxicity, but the link between oxidative stress and acrylamide cytotoxicity is still unclear. In the present study, hispidin produced from the edible fungus Phellinus linteus displayed dramatically antioxidant activities against DPPH radicals, ABTS radicals, ferric reducing and hydroxyl radicals, as well as superoxide anion radicals. Moreover, the cytoprotective effect of hispidin against AA-induced oxidative stress was verified upon Caco-2 cells according to evaluate the cell viability, intracellular ROS, mitochondrial membrane potential (MMP) and glutathione (GSH) in the presence or absence of AA (5 mM) in a dose-dependent manner. Collectively, our results demonstrated for the first time that hispidin was able to inhibit AA-induced oxidative stress, which might have implication for the dietary preventive application.

Antimicrobial effect of bayberry leaf extract for the preservation of large yellow croaker (Pseudosciaena crocea).

BACKGROUND: Chemical preservatives have been widely used to keep large yellow croaker fresh. However, the potential harm to human health cannot be ignored. This study was undertaken to investigate the antimicrobial effect of bayberry leaf extract and to evaluate the efficacy of this natural product on the preservation of large yellow croaker. RESULTS: The minimum inhibitory concentration (MIC) values of bayberry leaf extract against bacteria were 1.0 mg mL⁻¹ for Micrococcus luteus, 0.5 mg mL⁻¹ for Staphylococcus aureus, 0.25 mg mL⁻¹ for Escherichia coli, 0.5 mg mL⁻¹ for Pseudomonas aeruginosa, 0.0625 mg mL⁻¹ for Vibrio parahaemolyticus, and 0.03125 mg mL⁻¹ for Listeria monocytogenes, respectively. This result was confirmed by the diameters of inhibition zone (DIZ) assay. Further studies showed that the bacterial growth was significantly retarded when large yellow croaker was pretreated with bayberry leaf extract (2 g L⁻¹) compared to that in the control group. Moreover, the generation of total volatile basic nitrogenous compounds (TVB-N), ATP degradation products (K-value) and thiobarbituric acid-reactive substances (TBARS) were significantly reduced compared to that in the control group. CONCLUSION: Our results demonstrated that the shelf life of large yellow croaker can be extended when supplemented with bayberry leaf extract, which might have implications for natural preservatives.

Myricitrin inhibits acrylamide-mediated cytotoxicity in human Caco-2 cells by preventing oxidative stress.

Oxidative stress was thought to be associated with acrylamide cytotoxicity, but the link between oxidative stress and acrylamide cytotoxicity in the gastrointestinal tract, the primary organ in contact with dietary acrylamide, is still unclear. This study was conducted to evaluate the antioxidant activity of natural dietary compound myricitrin and its protective role against acrylamide cytotoxicity. We found that myricitrin can effectively scavenge multiple free radicals (including DPPH free radical, hydroxyl radical, and ABTS free radical) in a concentration-dependent manner. Our results further indicated that the presence of myricitrin (2.5-10 µg/mL) was found to significantly inhibit acrylamide-induced cytotoxicity in human gastrointestinal Caco-2 cells. Moreover, acrylamide-induced cytotoxicity is closely related to oxidative stress in Caco-2 cells. Interestingly, myricitrin was able to suppress acrylamide toxicity by inhibiting ROS generation. Taken together, these results demonstrate that myricitrin had a profound antioxidant effect and can protect against acrylamide-mediated cytotoxicity.

Protective properties of tanshinone I against oxidative DNA damage and cytotoxicity.

Tanshinone I, a naturally occurring diterpene from Danshen, has been shown to possess hepatocyte protective, anticancer, and memory enhancing properties. However, there are few stringent pharmacological tests for neuroprotection of tanshinone I thus far. Since peroxynitrite is involved in the pathogenesis of neurodegenerative disorders, this study was undertaken to investigate whether the neuroprotective effect of tanshinone I is associated with inhibition of peroxynitrite-caused DNA damage, a critical event leading to peroxynitrite-induced cytotoxicity. Our results show that tanshinone I can significantly inhibit peroxynitrite-induced DNA damage both in φX-174 plasmid DNA and rat primary astrocytes. EPR spectroscopy indicates that tanshinone I potently diminished the DMPO-hydroxyl radical adduct signal from peroxynitrite. Taken together, these results demonstrate for the first time that tanshinone I can protect against peroxynitrite-induced DNA damage, hydroxyl radical formation and cytotoxicity, which might have implications for tanshinone I-mediated neuroprotection.