Lycium barbarum polysaccharides inhibit ischemia/reperfusion-induced myocardial injury via the Nrf2 antioxidant pathway

Lycium barbarum polysaccharides attenuate oxidative stress and mitochondrial toxicity induced by mixed plasticizers in HepG2 cells through activation of Nrf2

AIMS

In daily life, it is common for humans to be exposed to multiple phthalate esters (PAEs). However, there is limited research on the mechanisms and intervention of combined PAEs toxicity. This study aims to explore the cytotoxicity of combined PAEs and evaluate the potential of Lycium barbarum polysaccharides (LBP) in mitigating the aforementioned toxicity.

MAIN METHODS

LBP (62.5, 125 and 250 μg/mL) were applied to intervene HepG2 cells treated with DEHP and DBP mixtures (50, 100, 200, 400 and 800 μg/mL). Western Blot and different kits were mainly performed in our study.

KEY FINDINGS

DEHP and DBP mixtures suppressed the expression of nuclear factor E2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1) and activated MAPK pathway by increasing ROS. Combined DEHP and DBP exposure reduced ATP content and inhibited the mitochondrial biogenesis pathway in HepG2 cells through oxidative stress, which in turn caused cytotoxicity. LBP reduced oxidative stress and cell death induced by mixed plasticizers, upregulated Nrf2 levels and mitochondrial biogenesis pathway levels and inhibited MAPK pathway activation. Notably, after treating HepG2 cells with Nrf2-specific inhibitor (ML385, 0.5 μM), we found that the activation of Nrf2 played a crucial role on LBP intervention of DEHP and DBP induced HepG2 cytotoxicity.

SIGNIFICANCE

This study not only enhances our understanding of the toxicological effects caused by combined PAEs exposure, but also has significant implications in devising strategies to mitigate the toxicological consequences of combined exposure to exogenous chemicals through the investigation of the role of LBP.

lncRNA HOTAIR promotes ROS generation and NLRP3 inflammasome activation by inhibiting Nrf2 in diabetic retinopathy

BACKGROUND

Diabetic retinopathy (DR) is a microvascular complication associated with damage to the retina due to inflammation induced by high glucose. Activation of the NLRP3 inflammasome plays a critical role in DR and its prevention is beneficial to patients. However, the regulation of long non-coding RNA (lncRNA) in NLRP3 inflammasome activation of DR is incompletely understood. So, this study aimed to uncover the functional and regulatory mechanism of the lncRNA HOTAIR in NLRP3 inflammasome activation in Dr.

METHODS

The vitreous humor was collected from the patients and detected the inflammatory and oxidative stress makers. Human retinal endothelial cells (HRECs) were cultured and stimulated in low D-glucose (5 mmol/L) or high D-glucose (20 mmol/L). Additionally, HRECs were knocked down HOTAIR with a si-RNA. Then, the NLRP3 inflammasome activation was analyzed by western blotting and pyroptosis cell imaging. The ROS was measured by specific probe. The activation of Nrf2 measured by Immunofluorescent staining. The interaction between HOTAIR and Nrf2 was evaluated by co-immunoprecipitation and RNA immunoprecipitation.

RESULTS

The expression of HOTAIR was significantly increased in the vitreous of patients with DR and in HRECs stimulated with high glucose. Furthermore, HOTAIR knockdown relieved NLRP3 inflammasome activation. More specifically, HOTAIR knockdown suppressed the expression of NLRP3, pro-caspase-1, and pro-IL-1β, as well as IL-1β maturation and pyroptosis. HOTAIR knockdown also interfered with the ROS generation induced by high glucose. Moreover, HOTAIR promoted the interaction between Nrf2 and Keap1 by binding and inactivating Nrf2.

CONCLUSION

The lncRNA HOTAIR promotes NLRP3 inflammasome activation and ROS generation by inhibiting Nrf2 in Dr.

Myocardial ischemia-reperfusion injury; Molecular mechanisms and prevention

Cardiovascular diseases are one of the leading causes of mortality in developed countries. Among cardiovascular disorders, myocardial infarction remains a life-threatening problem predisposing to the development and progression of ischemic heart failure. Ischemia/reperfusion (I/R) injury is a critical cause of myocardial injury. In recent decades, many efforts have been made to find the molecular and cellular mechanisms underlying the development of myocardial I/R injury and post-ischemic remodeling. Some of these mechanisms are mitochondrial dysfunction, metabolic alterations, inflammation, high production of ROS, and autophagy deregulation. Despite continuous efforts, myocardial I/R injury remains a major challenge in medical treatments of thrombolytic therapy, heart disease, primary percutaneous coronary intervention, and coronary arterial bypass grafting. The development of effective therapeutic strategies to reduce or prevent myocardial I/R injury is of great clinical significance.

Advances in health-promoting effects of natural polysaccharides: Regulation on Nrf2 antioxidant pathway

Natural polysaccharides (NPs) possess numerous health-promoting effects, such as liver protection, kidney protection, lung protection, neuroprotection, cardioprotection, gastrointestinal protection, anti-oxidation, anti-diabetic, and anti-aging. Nuclear factor erythroid 2-related factor 2 (Nrf2) antioxidant pathway is an important endogenous antioxidant pathway, which plays crucial roles in maintaining human health as its protection against oxidative stress. Accumulating evidence suggested that Nrf2 antioxidant pathway might be one of key regulatory targets for the health-promoting effects of NPs. However, the information concerning regulation of NPs on Nrf2 antioxidant pathway is scattered, and NPs show different regulatory behaviors in their different health-promoting processes. Therefore, in this article, structural features of NPs having regulation on Nrf2 antioxidant pathway are overviewed. Moreover, regulatory effects of NPs on this pathway for health-promoting effects are summarized. Furthermore, structure-activity relationship of NPs for health-promoting effects by regulating the pathway is preliminarily discussed. Otherwise, the prospects on future work for regulation of NPs on this pathway are proposed. This review is beneficial to well-understanding of underlying mechanisms for health-promoting effects of NPs from the view angle of Nrf2 antioxidant pathway, and provides a theoretical basis for the development and utilization of NPs in promoting human health.

Combined Photothermal Therapy and Lycium barbarum Polysaccharide for Topical Administration to Improve the Efficacy of Doxorubicin in the Treatment of Breast Cancer

In order to improve the efficacy of doxorubicin in the treatment of breast cancer, we constructed a drug delivery system combined with local administration of Lycium barbarum polysaccharides (LBP) and photothermal-material polypyrrole nanoparticles (PPY NPs). In vitro cytotoxicity experiments showed that the inhibitory effect of DOX + LBP + PPY NPs on 4T1 cells under NIR (near infrared) laser was eight times that of DOX at the same concentration (64% vs. 8%). In vivo antitumor experiments showed that the tumor inhibition rate of LBP + DOX + PPY NPs + NIR reached 87.86%. The results of the H&E staining and biochemical assays showed that the systemic toxicity of LBP + DOX + PPY NPs + NIR group was reduced, and liver damage was significantly lower in the combined topical administration group (ALT 54 ± 14.44 vs. 28 ± 3.56; AST 158 ± 16.39 vs. 111 ± 20.85) (p < 0.05). The results of the Elisa assay showed that LBP + DOX + PPY NPs + NIR can enhance efficacy and reduce toxicity (IL-10, IFN-γ, TNF-α, IgA, ROS). In conclusion, LBP + DOX + PPY NPs combined with photothermal therapy can improve the therapeutic effect of DOX on breast cancer and reduce its toxic side effects.

Isolation and characterization of fucoidan from four brown algae and study of the cardioprotective effect of fucoidan from Sargassum wightii against high glucose-induced oxidative stress in H9c2 cardiomyoblast cells

Oxidative stress plays a vital role in the initiation and progression of diabetic cardiomyopathy (DCM). Increased cardiac dysfunction and apoptosis in DCM are independent factors associated with hypertension or coronary artery disease. Fucoidan, a class of sulfated polysaccharides, is widely used as food supplements and reported to have various pharmacological properties. However, the pharmacological property of Indian seaweeds remains unexplored. The present study is focused on isolating and characterizing the fucoidan from four brown seaweeds such as Sargassum wightii (SwF), Sargassum swartzii (SsF), Sargassum polycystum (SpF), Turbinaria ornata (ToF), and aimed to investigate cardioprotective effect of fucoidan against High Glucose (HG) induced oxidative stress in H9c2 cells. The mild acid hydrolysis method was used to isolate crude fucoidan from four brown seaweeds purified by the FPLC system. The biochemical composition analysis showed that SwF had a high content of fucoidan and sulfate, followed by SsF, SpF, and ToF. Further, FTIR, XRD, NMR, and SEM analysis confirmed the isolated fucoidan structures. SwF showed higher DPPH activity compared to another isolated fucoidan. In vitro studies with SwF revealed significantly decreased cytotoxicity, prevented the loss of MMP, reduced lipid peroxidation, and increased cellular enzymatic and non-enzymatic activity. qRT-PCR results showed SwF significantly upregulated the Nrf2, HO-1, NQO1, and Bcl2 and down-regulated the Bax and Caspase-3 mRNA expression compared to HG-treated cells. In conclusion, SwF could be used to develop functional foods for diabetic-mediated CVD complications compared to another isolated fucoidan. PRACTICAL APPLICATIONS: Bioactive carbohydrates have gained significant interest among researchers to improve human health. The biomedical field showed great interest in seaweed research in managing various diseases. In particular, seaweeds contain many bioactive compounds because of their chemical and biological diversity. Despite the various beneficial effects of fucoidan in CVD, the therapeutic potential of Indian seaweeds remains largely unexplored. Hence, this study isolated fucoidan from four brown seaweeds and studied their bioactive properties. Results revealed that SwF showed higher free radical scavenging activity compared to another isolated fucoidan. Therefore, SwF was selected for the in vitro study. SwF increased the cytoprotection through increasing antioxidant levels against oxidative stress in H9c2 cells. Staining analysis showed SwF increased cellular protection via inhibiting ROS protection and increasing MMP. Overall, fucoidan from SwF could be developed as a functional food for CVD.

An aqueous extract of the brown alga Eisenia bicyclis extends lifespan in a sex-specific manner by interfering with the Tor-FoxO axis

Food has a decisive influence on our health, to the extent where even lifespan can be directly affected by it. In the present work, we have examined the effects of an aqueous extract of the marine brown alga Eisenia bicyclis in terms of its potential to extend lifespan. For this purpose, we used the fruit fly Drosophila melanogaster as a model. The experiments showed that small amounts of Eisenia extract can extend lifespan by up to 40%. This effect is not only related to the median but also to the maximum lifespan. Interestingly, this life-extending effect is sex-specific, i.e. it occurs exclusively in females. Even under stressful nutritional conditions such as a high sugar diet, this effect is detectable. Mechanistic studies showed that this life-prolonging effect depends on a functional Tor and a functional FoxO signaling pathway. It can be concluded that components of the Eisenia extract prolong lifespan by interacting with the Tor-FoxO axis. This study may serve to stimulate further investigations, which on the one hand show such a life-prolonging effect also in other organisms and on the other hand identify the substances responsible for this effect. Finally, it may also encourage the increased use of arame as a health-promoting food supplement.

Targeting Nrf2 in ischemia-reperfusion alleviation: From signaling networks to therapeutic targeting

The nuclear factor erythroid 2-related factor 2 (Nrf2) is a master regulator of redox balance and it responds to various cell stresses that oxidative stress is the most well-known one. The Nrf2 should undergo nuclear translocation to exert its protective impacts and decrease ROS production. On the other hand, ischemic/reperfusion (I/R) injury is a pathological event resulting from low blood flow to an organ and followed by reperfusion. The I/R induces cell injury and organ dysfunction. The present review focuses on Nrf2 function in alleviation of I/R injury. Stimulating of Nrf2 signaling ameliorates I/R injury in various organs including lung, liver, brain, testis and heart. The Nrf2 enhances activity of antioxidant enzymes to reduce ROS production and prevent oxidative stress-mediated cell death. Besides, Nrf2 reduces inflammation via decreasing levels of pro-inflammatory factors including IL-6, IL-1β and TNF-α. Nrf2 signaling is beneficial in preventing apoptosis and increasing cell viability. Nrf2 induces autophagy to prevent apoptosis during I/R injury. Furthermore, it can interact with other molecular pathways including PI3K/Akt, NF-κB, miRNAs, lncRNAs and GSK-3β among others, to ameliorate I/R injury. The therapeutic agents, most of them are phytochemicals such as resveratrol, berberine and curcumin, induce Nrf2 signaling in I/R injury alleviation.

Lycium barbarum Polysaccharides as Antibiotic Substitutes Improve Growth Performance, Serum Immunity, Antioxidant Status, and Intestinal Health for Weaned Piglets

The aim of the present study is to investigate the effects of dietary Lycium barbarum polysaccharides (LBPs) supplementation on the growth performance, immune response, serum antioxidant status, and intestinal health of weaned piglets. In total, 24 crossed healthy weaned piglets [Duroc × (Yorkshire × Landrace)], of similar body weight (7.47 ± 0.22 kg), were randomly allocated to three treatment groups: CON (basal diet); LBPs (basal diet plus 4,000 mg/kg LBPs); and antibiotic (ABO, basal diet plus 20 mg/kg flavomycin and 50 mg/kg quinocetone). There were eight pigs per group. The study lasted 28 days. When compared with CON, LBPs or ABO dietary supplementation increased average daily gain (P < 0.05), decreased the ratio of feed to gain and the diarrhea ratio (P < 0.05). Similarly, when compared with CON, LBPs dietary supplementation increased serum immunoglobulin G, immunoglobulin M, interleukin-10, interleukin-2, and tumor necrosis factor-α levels (P < 0.05). Dietary LBPs enhanced the activity of serum total antioxidant capacity and glutathione peroxidase, and decreased malondialdehyde levels (P < 0.05). Principal component analysis showed a distinct separation between CON and LBPs groups, but no differences between ABO and LBPs groups. LBPs addition increased Lactobacillus and Faecalibacterium (P < 0.05) levels, while it decreased Enterococcaceae and Enterobacteriaceae (P < 0.05) levels. Furthermore, when compared with the CON group, LBPs increased villus height (P < 0.05) and the villus height to crypt depth ratio in the duodenum and jejunum (P < 0.05). Thus, dietary supplementation with LBPs improved growth performance, antioxidant capacity and immunity, regulated intestinal microbial composition, and may be used as an efficient antibiotic alternative in weaned piglet feed.

Lycium barbarum Polysaccharides and Capsaicin Inhibit Oxidative Stress, Inflammatory Responses, and Pain Signaling in Rats with Dextran Sulfate Sodium-Induced Colitis

Ulcerative colitis (UC) is an inflammatory disease with chronic relapsing symptoms. This study investigated the effects of Lycium barbarum polysaccharides (LBP) and capsaicin (CAP) in dextran sulfate sodium (DSS)-induced UC rats. Rats were divided into normal, DSS-induced UC, and UC treated with 100 mg LBP/kg bw, 12 mg CAP/kg bw, or 50 mg LBP/kg bw and 6 mg CAP/kg bw. Rats were fed LBP or CAP orally by gavage for 4 weeks, and UC model was established by feeding 5% DSS in drinking water for 6 days during week 3. Oral CAP and mixture significantly reduced disease activity index. Oral LBP significantly decreased serum malondialdehyde, interleukin (IL)-6, colonic tumor necrosis factor (TNF)-α levels, and protein expression of transient receptor potential cation channel V1 (TRPV1) and transient receptor potential ankyrin 1 (TRPA1), but increased serum catalase activity. Oral CAP significantly suppressed serum IL-6, colonic TRPV1 and TRPA1 protein expression, but elevated IL-10 levels, serum superoxide dismutase and catalase activities. The mixture of LBP and CAP significantly reduced serum IL-6, colonic TNF-α and TRPA1 protein. In conclusion, administration of LBP and/or CAP attenuate DSS-induced UC symptoms through inhibiting oxidative stress, proinflammatory cytokines, and protein expression of TRPV1 and TRPA1.

Vitamin D3 Protects Mice from Diquat-Induced Oxidative Stress through the NF-κB/Nrf2/HO-1 Signaling Pathway

Vitamin D₃, as an indispensable and fat-soluble micronutrient, plays an important role in the health of humans and animals. At present, studies are focusing on the calcium absorption and immunoregulation function of vitamin D₃; this study was aimed at exploring the antioxidative stress ability of vitamin D₃ on diquat-induced intestinal dysfunction of ICR mice and the underlying mechanism. The results showed that oral gavage of vitamin D₃ daily significantly improved the body weight gain and immune organ index and significantly reverted the abnormal changes of ALT, AST, SOD, GSH-Px, T-AOC, and MDA in the serum and jejunum induced by diquat. The addition of vitamin D₃ also significantly reduced the concentration of DAO, D-LA, and certain proinflammatory cytokines in serum. Moreover, vitamin D₃ improved the pathological morphology of the duodenum, jejunum, colon, liver, and kidney tissues, and it also largely attenuated the degree of inflammatory infiltration of macrophages and cell apoptotic index of jejunal epithelial tissue induced by diquat. The results demonstrated that vitamin D₃ significantly recovered the intestinal barrier injury by enhancing the expression of mucins and tight junction proteins in the jejunum. In addition, the results indicated that vitamin D₃ could significantly reduce the phosphorylation level of NF-κB (p65) and enhance the expression of Nrf2 and HO-1 in the jejunum compared with the diquat-induced group. This study suggested that oral administration of vitamin D₃ can protect mice against oxidative damage by inhibiting the phosphorylation level of NF-κB (p65) and activating Nrf2-related signaling pathways.