The Dose-Response Effect of Lycopene on Cerebral Vessel and Neuron Impairment Induced by Hyperlipidemia

Much More than Nutrients: The Protective Effects of Nutraceuticals on the Blood-Brain Barrier in Diseases

The dysfunction of the blood-brain barrier (BBB) is well described in several diseases, and is considered a pathological factor in many neurological disorders. This review summarizes the most important groups of natural compounds, including alkaloids, flavonoids, anthocyanidines, carotenoids, lipids, and vitamins that were investigated for their potential protective effects on brain endothelium. The brain penetration of these compounds and their interaction with BBB efflux transporters and solute carriers are discussed. The cerebrovascular endothelium is considered a therapeutic target for natural compounds in diseases. In preclinical studies modeling systemic and central nervous system diseases, nutraceuticals exerted beneficial effects on the BBB. In vivo, they decreased BBB permeability, brain edema, astrocyte swelling, and morphological changes in the vessel structure and basal lamina. At the level of brain endothelial cells, nutraceuticals increased cell survival and decreased apoptosis. From the general endothelial functions, decreased angiogenesis and increased levels of vasodilating agents were demonstrated. From the BBB functions, elevated barrier integrity by tightened intercellular junctions, and increased expression and activity of BBB transporters, such as efflux pumps, solute carriers, and metabolic enzymes, were shown. Nutraceuticals enhanced the antioxidative defense and exerted anti-inflammatory effects at the BBB. The most important signaling changes mediating the increased cell survival and BBB stability were the activation of the WNT, PI3K-AKT, and NRF2 pathways, and inhibition of the MAPK, JNK, ERK, and NF-κB pathways. Nutraceuticals represent a valuable source of new potentially therapeutic molecules to treat brain diseases by protecting the BBB.

Lycopene Alleviates Chronic Stress-Induced Hippocampal Microglial Pyroptosis by Inhibiting the Cathepsin B/NLRP3 Signaling Pathway

Lycopene (LYC) exerts a strong neuroprotective and antipyroptotic effects. This study explored the effects and mechanisms of LYC on chronic stress-induced hippocampal microglial damage and depression-like behaviors. The caspase-1 inhibitor VX-765 attenuated chronic restrain stress (CRS)-induced hippocampal microglial pyroptosis and depression-like behaviors. Moreover, the alleviation of CRS-induced hippocampal microglial pyroptosis and depression-like behaviors by LYC was associated with the cathepsin B/NLRP3 pathway. In vitro, the caspase-1 inhibitor Z-YVAD-FMK alleviated pyroptosis in highly aggressively proliferating immortalized (HAPI) cells. Additionally, the alleviation of corticosterone-induced HAPI cell damage and pyroptosis by LYC was associated with the cathepsin B/NLRP3 pathway. Furthermore, the cathepsin B agonist pazopanib promoted HAPI cell pyroptosis, whereas LYC inhibited pazopanib-induced pyroptosis via the cathepsin B/NLRP3 pathway. Similarly, Z-YVAD-FMK inhibited pazopanib-induced HAPI cell pyroptosis. These results suggest that LYC alleviates chronic stress-induced hippocampal microglial pyroptosis via the cathepsin B/NLRP3 pathway inhibition. This study provides a new strategy for treating chronic stress encephalopathy.

The sources, properties, extraction, biosynthesis, pharmacology, and application of lycopene

Lycopene is an important pigment with an alkene skeleton from Lycopersicon esculentum, which is also obtained from some red fruits and vegetables. Lycopene is used in the food field with rich functions and serves in the medical field with multiple clinical values because it has dual functions of both medicine and food. It was found that lycopene was mainly isolated by solvent extraction, ultrasonic-assisted extraction, supercritical fluid extraction, high-intensity pulsed electric field-assisted extraction, enzymatic-assisted extraction, and microwave-assisted extraction. Meanwhile, it was also obtained via 2 synthetic pathways: chemical synthesis and biosynthesis. Pharmacological studies revealed that lycopene has anti-oxidant, hypolipidemic, anti-cancer, immunity-enhancing, hepatoprotective, hypoglycemic, cardiovascular-protective, anti-inflammatory, neuroprotective, and osteoporosis-inhibiting effects. The application of lycopene mainly includes food processing, animal breeding, and medical cosmetology fields. It is hoped that this review will provide some useful information and guidance for future study and exploitation of lycopene.

Protective effects of lycopene on TiO2 nanoparticle-induced damage in the liver of mice

Titanium dioxide nanoparticles (nano-TiO₂ ) is one of the most widely used and produced nanomaterials. Studies have demonstrated that nano-TiO₂ could induce hepatotoxicity through oxidative stress, and lycopene has strong antioxidant capacity. The present study aimed to explore if lycopene protects the liver of mice from nano-TiO₂ damage. Ninety-six ICR mice were randomly divided into eight groups. They were control group, nano-TiO₂ -treated group (50 mg/kg BW), lycopene-treated groups (5, 20, and 40 mg/kg BW), and 50 mg/kg BW nano-TiO₂ - and lycopene-co-treated groups (nano-TiO₂  + 5 mg/kg BW of lycopene, nano-TiO₂  + 20 mg/kg BW of lycopene, nano-TiO₂  + 40 mg/kg BW of lycopene). After treated by gavage for 30 days, the histopathology of the liver was observed. Liver function was evaluated using changes in serum biochemical indicators of the liver (AST, ALT, ALP); and the level of ROS was indirectly reflected by the level of SOD, GSH-Px, MDA, GSH, and T-AOC. TUNEL assay was performed to examine the apoptosis of hepatocytes. Proteins of p53, cleaved-caspase 9, cleaved-caspase 3, Bcl-2, and Bax as well as p38 were detected. Results showed that lycopene alleviated the liver pathological damage and reduced the injury to liver function induced by nano-TiO₂ , as well as decreased nano-TiO₂ -induced ROS. Meanwhile, lycopene mitigated apoptosis resulting from nano-TiO₂ , accompanied by the reversed expression of apoptosis-related proteins. Furthermore, lycopene significantly reversed the upregulation of p-p38 induced by nano-TiO₂ . In conclusion, this study demonstrated that nano-TiO₂ resulted in hepatocyte apoptosis through ROS/ROS-p38 MAPK pathway and led to liver function injury. Lycopene protected mice liver against the hepatotoxicity of nano-TiO₂ through antioxidant property.

Lycopene: a therapeutic strategy against coronavirus disease 19 (COVID- 19)

Lycopene is a group of phytochemicals found in nature, primarily in fruits and vegetables. Lycopene is thought to protect against a variety of diseases attributed to its antioxidant capabilities. Lycopene has anti-inflammatory, anti-cancer, and immunity-boosting qualities, among other biological and pharmacological benefits. COVID-19 (coronavirus disease 19) is an infectious disease caused by the SARS-CoV-2 virus, which has recently emerged as one of the world's leading causes of death. Patients may be asymptomatic or show signs of respiratory, cytokine release syndrome, gastrointestinal, or even multiple organ failure, all of which can lead to death. In COVID-19, inflammation, and cytokine storm are the key pathogenic mechanisms, according to SARS-CoV-2 infection symptoms. ARDS develops in some vulnerable hosts, which is accompanied by an inflammatory "cytokine syndrome" that causes lung damage. Immunological and inflammatory markers were linked to disease severity in mild and severe COVID-19 cases, implying that inflammatory markers, including IL-6, CRP, ESR, and PCT were significantly linked with COVID-19 severity. Patients with severe illness have reduced levels of several immune subsets, including CD4 + T, NK, and CD8 + cells. As a result, lycopene can be commended for bolstering physiological defenses against COVID-19 infections.

Differential proteomic analysis of mouse cerebrums with high-fat diet (HFD)-induced hyperlipidemia

Hyperlipidemia is a chronic disease characterized by elevated blood cholesterol and triglycerides and there is accumulated evidence that the disease might affect brain functions. Here we report on a proteomic analysis of the brain proteins in hyperlipidemic mice. Hyperlipidemia was successfully induced in mice by a 20 week high-fat diet (HFD) feeding (model group). A control group with a normal diet and a treatment group with HFD-fed mice treated with a lipid-lowering drug simvastatin (SIM) were established accordingly. The proteins were extracted from the left and right cerebrum hemispheres of the mice in the three groups and subjected to shotgun proteomic analysis. A total of 4,422 proteins were detected in at least half of the samples, among which 324 proteins showed significant difference (fold change >1.5 or <0.67, p < 0.05) in at least one of the four types of comparisons (left cerebrum hemispheres of the model group versus the control group, right cerebrums of model versus control, left cerebrums of SIM versus model, right cerebrums of SIM versus model). Biological process analysis revealed many of these proteins were enriched in the processes correlated with lipid metabolism, neurological disorders, synaptic events and nervous system development. For the first time, it has been reported that some of the proteins have been altered in the brain under the conditions of HFD feeding, obesity or hyperlipidemia. Further, 22 brain processes-related proteins showed different expression in the two cerebrum hemispheres, suggesting changes of the brain proteins caused by hyperlipidemia might also be asymmetric. We hope this work will provide useful information to understand the effects of HFD and hyperlipidemia on brain proteins.

Lycopene Alleviates Chronic Stress-Induced Spleen Apoptosis and Immunosuppression via Inhibiting the Notch Signaling Pathway in Rats

Chronic stress induction in immunosuppression and splenocyte apoptosis is commonly associated with increased susceptibility to various diseases. Lycopene (LYC) is a member of the carotenoid family with immune restoration and anti-apoptotic function. However, little is known about the mechanisms underlying the protective roles of LYC against spleen injury induced by chronic stress. Herein, male Wistar rats were undergoing chronic restraint stress and/or administered LYC (10 mg/kg) for 21 days. The effective model establishment was validated by open-field tests and levels of corticosterone in serum. Histopathological staining observation displayed that LYC could reduce chronic stress-induced spleen structure damage. Furthermore, LYC treatment significantly reduced the number of apoptotic-positive splenocytes caused by chronic stress via the death receptor apoptotic pathway. We detected the interleukin 4 and interferon γ levels in serum and spleen to determine the ratio of Th1 and Th2 and found that LYC can alleviate the immunosuppression induced by chronic stress. Notably, western blot and real-time polymerase chain reaction indicated that LYC can reduce the expression of the Notch-pathway-related proteins and mRNA in rats exposed to chronic stress. Further study of the potential mechanisms by adding the Notch pathway inhibitor DAPT revealed that LYC alleviates the structure damage, apoptosis, and immunosuppression caused by chronic stress via the suppression of the Notch pathway. Overall, this study presents a strong rationale to target LYC as a treatment strategy to relieve chronic stress-induced spleen injury.

Lycopene Regulates Dietary Dityrosine-Induced Mitochondrial-Lipid Homeostasis by Increasing Mitochondrial Complex Activity

SCOPE

Dityrosine (DT), a marker of protein oxidation, is widely found in many high-protein foods. Dietary intake of DT induces myocardial oxidative stress injury and impairs energy metabolism. Lycopene is a common dietary supplement with antioxidant and mitochondrial-lipid homeostasis modulating abilities. This study aimed to examine the effects of lycopene on DT-induced disturbances in myocardial function and energy metabolism.

METHODS AND RESULTS

Four-week-old C57BL/6J mice received intragastric administration of either tyrosine (420 µg kg^-1 BW), DT (420 µg kg^-1 BW), or lycopene at high (10 mg kg^-1 BW) and low (5 mg kg^-1 BW) doses for 35 days. Lycopene administration effectively reduced oxidative stress, cardiac fatty acid accumulation, and cardiac hypertrophy and improved mitochondrial performance in DT-induced mice. In vitro experiments in H9c2 cells showed that DT directly inhibited the activity of the respiratory chain complex, whereas oxidative phosphorylation and β-oxidation gene expression is upregulated. Lycopene enhanced the activity of the complexes and inhibited ROS production caused by compensatory regulation.

CONCLUSION

Lycopene improves DT-mediated myocardial energy homeostasis disorder by promoting the activity of respiratory chain complexes I and IV and alleviates the accumulation of cardiac fatty acids and myocardial hypertrophy.

Lycopene modulates lipid metabolism in rats and their offspring under a high-fat diet

The purpose of this study was to investigate the effects of lycopene supplementation on lipid metabolism in rats and their offspring. The experiment was conducted on 60 female rats divided into four groups: normal diet, normal diet with 200 mg kg^-1 lycopene, high-fat diet, and high-fat diet with 200 mg kg^-1 lycopene. The plasma levels of TG, LDL-C, AST and ALT in female rats fed a high-fat diet were significantly increased (P < 0.05). Lycopene supplementation reduced the plasma TG, LEP and AST levels (P < 0.05). In addition, the activity of ACC and mRNA expression of SREBP1c, FAS, PPARγ, CPT1, HMGCR, ACC, PLIN1 and FATP1 in the liver were also increased after feeding a high-fat diet (P < 0.05), whereas the expression of HSL was decreased (P < 0.05). Lycopene increased the activity of HSL and the expression of ATGL in the liver (P < 0.05), and the activity of ACC and mRNA expression of HMGCR and ACC were decreased (P < 0.05). For the offspring, maternal feeding of a high-fat diet reduced the plasma HDL-C levels (P < 0.05), but lycopene supplementation reduced the plasma TC levels (P < 0.05). Maternal high-fat diet also decreased the activity of HSL and the expression of CD36, PLIN1 and FATP1 in the liver while increasing the expression of PPARγ (P < 0.05). Maternal lycopene supplementation decreased the activities of ACC and FAS in the liver and decreased the expression of PPARγ, ACC and PLIN1 (P < 0.05). Maternal feeding of a high-fat diet increased the level of oxidative stress in the liver, the level of blood lipids in plasma and the rate of lipid production in the liver of rats and their offspring. Maternal lycopene supplementation can reduce the level of oxidative stress in rats and their offspring, reduce the level of blood lipids in plasma, and also reduce the rate of lipid production in the liver of rats and offspring.

Lycopene increases the proportion of slow-twitch muscle fiber by AMPK signaling to improve muscle anti-fatigue ability

Lycopene has a wide range of biological functions, especially its antioxidant capacity. However, effects of lycopene on muscle fatigue resistant and muscle fiber type conversion are unknown. In this study, we found that lycopene significantly prolonged the swimming time to exhaustion in mice. We also showed that lycopene increased the proportion of slow-twitch muscle fiber by promoting muscle fiber type conversion from fast-twitch to slow-twitch in mice and in C2C12 myotubes. The AMP-activated protein kinase (AMPK) signaling was activated by lycopene. AMPK upstream and downstream regulators including nuclear respiratory factor 1, calcium calmodulin-dependent protein kinase kinase-β, sirtuin 1 and peroxisome proliferator activated receptor-γ coactivator-1ɑ were also increased by lycopene. AMPK inhibitor compound C markedly attenuated the lycopene-induced skeletal muscle fiber type conversion in C2C12 myotubes. Taken together, we provided the first evidence that lycopene increases the proportion of slow-twitch muscle fiber through AMPK signaling pathway to improve fatigue resistant of skeletal muscle.

Lycopene ameliorates chronic stress-induced hippocampal injury and subsequent learning and memory dysfunction through inhibiting ROS/JNK signaling pathway in rats

The natural carotenoid lycopene (LYC) has strong antioxidant and neuroprotective capacities. This study investigated the effects and mechanisms of LYC on chronic stress-induced hippocampal lesions and learning and memory dysfunction. Rats were administered LYC and/or chronic restraint stress (CRS) for 21 days. Morris water maze results demonstrated that LYC prevented CRS-induced learning and memory dysfunction. Histopathological staining and transmission electron microscopy observation revealed that LYC ameliorated CRS-induced hippocampal microstructural and ultrastructural damage. Furthermore, LYC alleviated CRS-induced oxidative stress by reducing reactive oxygen species (ROS) production and enhancing antioxidant enzyme activities. LYC also improved CRS-induced hippocampal mitochondrial dysfunction by recovering mitochondrial membrane potential, and complex I (NADH dehydrogenase) and II (succinate dehydrogenase) activities. Moreover, LYC reduced CRS-induced apoptosis via the mitochondrial apoptotic pathway, and decreased the number of terminal deoxynucleotidyl transferase dUTP nick-end-labeled positive cells. Additionally, western blot analysis demonstrated that LYC inhibited CRS-induced activation of the c-Jun N-terminal kinase (JNK) signaling pathway. Correlation analysis indicated that ROS levels, JNK activation, and the mitochondrial apoptotic pathway were positively correlated. Further investigation of the underlying mechanisms revealed that the ROS scavenger N-acetyl-l-cysteine inhibited CRS-induced JNK activation. Furthermore, the JNK inhibitor SP600125 relieved CRS-induced hippocampal mitochondrial dysfunction, apoptosis via the mitochondrial apoptotic pathway, and learning and memory dysfunction. Together, these results suggest that LYC alleviates hippocampal oxidative stress, mitochondrial dysfunction, and apoptosis by inhibiting the ROS/JNK signaling pathway, thereby improving CRS-induced hippocampal injury and learning and memory dysfunction. This study provides a theoretical basis and new therapeutic strategies for the application of LYC to relieve chronic stress encephalopathy.

Protective effects of lycopene in cancer, cardiovascular, and neurodegenerative diseases: An update on epidemiological and mechanistic perspectives

Recent mechanistic and epidemiological studies have provided insights into health benefits of dietary lycopene to decrease the risk and complications associated with several chronic diseases such as cardiovascular diseases (CVD), obesity, type 2 diabetes, cancer, and neurodegenerative disorders. These chronic diseases are primarily associated with oxidative stress-induced systemic and low-grade chronic inflammation. Owing to its potent antioxidant properties, lycopene can potentially alleviate enhanced levels of proinflammatory mediators (e.g., proinflammatory cytokines IL-8, -6, and -1, and oxidized phospholipids) and prevent NF-κB activation by modulating oxidative stress. Moreover, lycopene serves as a precursor for various oxidative cleavage products and metabolites including Apo-8'-, apo-10'-, and apo-12'-lycopenals that can interact with multiple transcription factors (e.g., Nrf2, RARs, RXRs, and PPARs) to overexpress antioxidant and cytoprotective Phase II enzymes and other growth-stimulating proteins (e.g., brain-derived neurotrophic factor (BDNF) for enhanced neuroprotection. These events altogether can protect the body from chronic inflammatory disorders. In the present review, the latest mechanistic development from cell and animal models and results of case-control, cohort, and randomized trials are discussed to support the protective part of lycopene in cancer, CVD, and neurodegenerative disorders. This review focuses on cellular and molecular events involved in protective effects of lycopene. Although molecular and cellular mechanisms involved in health-promoting activities of lycopene have been reported, no detailed mechanistic studies have been published. Hence, future studies should be conducted to elucidate the mechanistic role(s) of lycopene-derived oxidation products in modulating cellular signaling.