Torularhodin from Sporidiobolus pararoseus Attenuates d-galactose/AlCl3-Induced Cognitive Impairment, Oxidative Stress, and Neuroinflammation via the Nrf2/NF-κB Pathway

Transcriptomic and metabolomic analyses reveal the positive effect of moderate concentration of sodium chloride treatment on the production of β-carotene, torulene, and torularhodin in oleaginous red yeast Rhodosporidiobolus odoratus XQR

Carotenoids, a family of lipid-soluble pigments, have garnered growing interest for their health-promoting benefits and are widely utilized in the food, feed, pharmaceutical, and cosmetic industries. Rhodosporidiobolus odoratus, a representative oleaginous red yeast, is considered a promising alternative for producing high-value carotenoids including β-carotene, torulene, and torularhodin. Here, the impact of varying concentrations of NaCl treatments on carotenoid contents in R. odoratus XQR after 120 h of incubation was examined. The results indicated that, as compared to the control (59.37 μg/gdw), the synthesis of total carotenoids was significantly increased and entirely suppressed under low-to-moderate (0.25 mol/L: 68.06 μg/gdw, 0.5 mol/L: 67.62 μg/gdw, and 0.75 mol/L: 146.47 μg/gdw) and high (1.0, 1.25, and 1.5 mol/L: 0 μg/gdw) concentrations of NaCl treatments, respectively. Moreover, the maximum production of β-carotene (117.62 μg/gdw), torulene (21.81 μg/gdw), and torularhodin (7.04 μg/gdw) was achieved with a moderate concentration (0.75 mol/L) of NaCl treatment. Transcriptomic and metabolomic analyses suggested that the increase in β-carotene, torulene, and torularhodin production might be primarily attributed to the up-regulation of some key protein-coding genes involved in the terpenoid backbone biosynthesis (atoB, HMGCS, and mvaD), carotenoid biosynthesis (crtYB and crtI), and TCA cycle (pckA, DLAT, pyc, MDH1, gltA, acnA, IDH1/2, IDH3, sucA, sucB, sucD, LSC1, SDHA, and fumA/fumB). The present study not only demonstrates a viable method to concurrently increase the production of β-carotene, torulene, torularhodin, and total carotenoids in R. odoratus XQR, but it also establishes a molecular foundation for further enhancing their production through genetic engineering.

The effects of Ganoderma leucocontextum triterpenoids treatment on the D-galactose and aluminum chloride-induced Alzheimer-like pathology in mouse brain

ETHNOPHARMACOLOGY RELEVANCE

Ganoderma leucocontextum T.H. Li, W. Q. Deng M. Wang & H.P.Hu. is a highland herbal medicine that has been shown to nourish the nervesand prolong life. Nevertheless, there is no evidence to indicate that Ganoderma leucocontextum triterpenoids (GLTs) reduce the damage triggered by Alzheimer's disease (AD).

AIM OF THE STUDY

The aim of this investigation was to ascertain the protective effects of GLTs on AD mice models and cells, as well as to look into potential pathways.

MATERIALS AND METHODS

In this study, the phytochemical characterization of GLTs was performed by High Performance Liquid Chromatography (HPLC) and Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS). The AD mouse model was induced by injecting intraperitoneally with D-galactose (120 mg/kg) and administering orally with aluminum chloride (20 mg/kg) daily for 28 days. After that, donepezil (5 mg/kg) and GLTs (0.4, 0.8, and 1.6 g/kg) were administered orally for 35 days. During the treatment period, aluminum chloride (20 mg/kg) and D-galactose (120 mg/kg) were continuously administered. And the behavior of the animals and the molecular changes of the hippocampus were determined after the whole experimental procedure. Furthermore, BV-2 cells were employed to validate GLTs' anti-neuroinflammatory properties.

RESULTS

The total triterpenoids content was 443.12 ± 0.21 g/kg and was inferred to contain 19 classes of substances such as organic acids, amino acids, vitamins, flavonoids, and other chemicals in GLTs. Treatment of D-galactose/aluminum chloride-induced mouse with GLTs can ameliorate AD symptoms, counteract cognitive decline, improve Aβ1-42 deposition, reduce the expression level of pro-apoptotic proteins, and attenuate the activation of hippocampal microglia and astrocytes. GLTs significantly increased the expression of antioxidant enzymes and significantly reduced the expression of inflammatory factors. GLTs inhibits nuclear factor kappa B (NF-κB) nuclear translocation and preserves myd88/traf6-mediated mitogen-activated protein kinase (MAPK) phosphorylation. Furthermore, GLTs (2 and 5 mg/mL) inhibited the generation of nitric oxide and protected lipopolysaccharide (1 mg/L)-induced neuroinflammation in BV-2 cells.

CONCLUSIONS

Taken together, Ganoderma leucocontextum triterpenoids can improve cognitive functions, including learning and memory, by reducing neuroinflammation and oxidative stress, preventing apoptosis, and controlling amyloid genesis.

A New Method for Selective Extraction of Torularhodin from Red Yeast Using CO2-SFE Technique

Torularhodin is a dark pink colored carotenoid belonging to the xanthophylls group that can be biologically synthesized by red yeasts, especially by Rhodotorula and Sporobolomyces genera. The growing interest in this molecule is due to its biological activities such as antioxidant, anticholesterolemic, anti-inflammatory, antimicrobial, and anticancer. To satisfy potential commercial markets, numerous methods have been proposed to develop a cost-effective and environmentally friendly downstream process for the purification of torularhodin. However, obtaining high purity products without resorting to the use of toxic solvents, which can leave residues in the final preparations, remains a major challenge. In this context, the present study aimed to develop a new efficient method for the isolation of torularhodin from the red yeast Rhodotorula strain ELP2022 by applying the extraction technique with supercritical CO2 (CO2-SFE) in two sequential steps. In particular, in the first step, the dried lysed biomass of yeast was subjected to the action of CO2 in supercritical conditions (CO2SC) as sole solvent for extraction of apolar carotenoids. In the second step, the residual biomass was subjected to the action of CO2SC using ethanol as a polar co-solvent for the extraction of torularhodin. Both steps were carried out at different operating parameters of temperature (40 and 60 °C) and pressure (from 300 to 500 bar) with a constant CO2 flow of 6 L min-1. Regardless of the operating conditions used, this method allowed to obtain an orange-colored oily extract and a red-colored extract after the first and second step, respectively. In all trials, torularhodin represented no less than 95.2% ± 0.70 of the total carotenoids in the red extracts obtained from the second step. In particular, the best results were obtained by performing both steps at 40 °C and 300 bar, and the maximum percentage of torularhodin achieved was 97.9% ± 0.88. Since there are no data on the selective recovery of torularhodin from red yeast using the SFE technique, this study may be a good starting point to optimize and support the development of industrial production of torularhodin by microbial synthesis. This new method can significantly reduce the environmental impact of torularhodin recovery and can be considered an innovation for which an Italian patent application has been filed. In a circular bioeconomy approach, this method will be validated up to a pilot scale, culturing the strain Rhodotorula spp. ELP2022 on low-cost media derived from agri-food wastes.

Pongamol Alleviates Neuroinflammation and Promotes Autophagy in Alzheimer's Disease by Regulating the Akt/mTOR Signaling Pathway

Alzheimer's disease (AD), one of the neurodegenerative disorders, is highly correlated with the abnormal hyperphosphorylation of Tau and aggregation of β-amyloid (Aβ). Oxidative stress, neuroinflammation, and abnormal autophagy are key drivers of AD and how they contribute to neuropathology remains largely unknown. The flavonoid compound pongamol is reported to possess a variety of pharmacological activities, such as antioxidant, antibacterial, and anti-inflammatory. This study investigated the neuroprotective effect and its mechanisms of pongamol in lipopolysaccharide (LPS)-induced BV2 cells, d-galactose/sodium nitrite/aluminum chloride (d-gal/NaNO2/AlCl3)-induced AD mice, and Caenorhabditis elegans models. Our research revealed that pongamol reduced the release of inflammatory factors IL-1β, TNF-α, COX-2, and iNOS in LPS-induced BV2 cells. Pongamol also protected neurons and significantly restored memory function, inhibited Tau phosphorylation, downregulated Aβ aggregation, and increased oxidoreductase activity in the hippocampus of AD mice. In addition, pongamol reversed the nuclear transfer of NF-κB and increased the levels of Beclin 1 and LC3 II/LC3 I. Most importantly, the anti-inflammatory and promoter autophagy effects of pongamol may be related to the regulation of the Akt/mTOR signaling pathway. In summary, these results showed that pongamol has a potential neuroprotective effect, which greatly enriched the research on the pharmacological activity of pongamol for improving AD.

Research advancements in the maintenance mechanism of Sporidiobolus pararoseus enhancing the quality of soy sauce during fermentation

Soy sauce is a traditional condiment that undergoes microbial fermentation of various ingredients to achieve its desired color, scent, and flavor. Sporidiobolus pararoseus, which is a type of Rhodocerevisiae, shows promising potential as a source of lipids, carotenoids, and enzymes that can enrich the taste and color of soy sauce. However, there is currently a lack of systematic and comprehensive studies on the functions and mechanisms of action of S. pararoseus during soy sauce fermentation. In this review, it is well established that S. pararoseus produces lipids that are abundant in unsaturated fatty acids, particularly oleic acid, as well as various carotenoids, such as β-carotene, torulene, and torularhodin. These pigments are synthesized through the mevalonic acid pathway and possess remarkable antioxidant properties, acting as natural colorants. The synthesis of carotenoids is stimulated by high salt concentrations, which induces oxidative stress caused by NaCl. This stress further activates crucial enzymes involved in carotenoid production, ultimately leading to pigment formation. Moreover, S. pararoseus can produce high-quality enzymes that aid in the efficient utilization of soy sauce substrates during fermentation. Furthermore, this review focused on the impact of S. pararoseus on the color and quality of soy sauce and comprehensively analyzed its characteristics and ingredients. Thus, this review serves as a basis for screening high-quality oleaginous red yeast strains and improving the quality of industrial soy sauce production through the wide application of S. pararoseus.

Naringenin mitigates aluminum toxicity-induced learning memory impairments and neurodegeneration through amelioration of oxidative stress

Aluminum chloride (AlCl3) is a potent neurotoxic substance known to cause memory impairment and oxidative stress-dependent neurodegeneration. Naringenin (NAR) is a dietary flavonoid with potent antioxidant and anti-inflammatory properties which was implemented against AlCl3-induced neurotoxicity to ascertain its neuroprotective efficacy. Experimental neurotoxicity in mice was induced by exposure of AlCl3 (10 mg/kg, p.o.) followed by treatment with NAR (10 mg/kg, p.o.) for a total of 63 days. Assessed the morphometric, learning memory dysfunction (novel object recognition, T- and Y-maze tests), neuronal oxidative stress, and histopathological alteration in different regions of the brain, mainly cortex, hippocampus, thalamus, and cerebellum. AlCl3 significantly suppressed the spatial learning and memory power which were notably improved by administration of NAR. The levels of oxidative stress parameters nitric oxide, advanced oxidation of protein products, protein carbonylation, lipid peroxidation, superoxide dismutase, catalase, glutathione reductase, reduced glutathione, and the activity of acetylcholine esterase were altered 1.5-3 folds by AlCl3 significantly. Treatment of NAR remarkably restored the level of oxidative stress parameters and maintained the antioxidant defense system. AlCl3 suppressed the expression of neuronal proliferation marker NeuN that was restored by NAR treatment which may be a plausible mechanism. NAR showed therapeutic efficacy as a natural supplement against aluminum-intoxicated memory impairments and histopathological alteration through a mechanism involving an antioxidant defense system and neuronal proliferation.

Exercise improves cognitive dysfunction and neuroinflammation in mice through Histone H3 lactylation in microglia

BACKGROUND

Exercise is postulated to be a promising non-pharmacological intervention for the improvement of neurodegenerative disease pathology. However, the mechanism of beneficial effects of exercise on the brain remains to be further explored. In this study, we investigated the effect of an exercise-induced metabolite, lactate, on the microglia phenotype and its association with learning and memory.

RESULTS

Microglia were hyperactivated in the brains of AlCl3/D-gal-treated mice, which was associated with cognitive decline. Running exercise ameliorated the hyperactivation and increased the anti-inflammatory/reparative phenotype of microglia and improved cognition. Mice were injected intraperitoneally with sodium lactate (NaLA) had similar beneficial effects as that of exercise training. Exogenous NaLA addition to cultured BV2 cells promoted their transition from a pro-inflammatory to a reparative phenotype.

CONCLUSION

The elevated lactate acted as an "accelerator" of the endogenous "lactate timer" in microglia promoting this transition of microglia polarization balance through lactylation. These findings demonstrate that exercise-induced lactate accelerates the phenotypic transition of microglia, which plays a key role in reducing neuroinflammation and improving cognitive function.

Nervonic acid reduces the cognitive and neurological disturbances induced by combined doses of D-galactose/AlCl3 in mice

Nervonic acid (NA) is a kind of ultra-long-chain monounsaturated fatty acid, which can repair nerve cell damage caused by oxidative stress. Alzheimer's disease (AD) is a nervous system disease and often accompanied by the decline of learning and memory capacity. In this study, the combined dose of D-galactose/AlCl3 was used to establish a mouse model of AD. Meanwhile, the mice were treated with different doses of NA (10.95 and 43.93 mg/kg). The results showed that NA delayed the decline of locomotion and learning ability caused by D-galactose/AlCl3, increased the activity of total superoxide dismutase, catalase, glutathione peroxidase, and reduced the content of malondialdehyde in vivo. Besides, NA reduced the levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), aspartate aminotransferase, alanine aminotransferase, increased the levels of 5-hydroxytryptamine, dopamine, γ-aminobutyric acid, alleviated the cell morphology damage induced by D-galactose/AlCl3 in hippocampus and liver tissue. Furthermore, the intervention of NA upregulated the expression levels of PI3K, AKT, and mTOR genes and downregulated the expression levels of TNF-α, IL-6, and IL-1β genes. Therefore, we speculate the intervention of NA could be an effective way in improving cognitive impairment through the activation of PI3K signaling pathway. These results suggest that NA has the potential to be developed as antioxidant drug for the prevention and early therapy of AD.

Ginsenoside Rh4 Alleviates Amyloid β Plaque and Tau Hyperphosphorylation by Regulating Neuroinflammation and the Glycogen Synthase Kinase 3β Signaling Pathway

Alzheimer's disease (AD) is a primary neurodegenerative disease. It can be caused by aging and brain trauma and severely affects the abilities of cognition and memory of patients. Therefore, it seriously threatens the mental and physical health of humans worldwide. As a traditional Chinese medicine, ginsenosides have been proven to have a variety of pharmacological activities. Ginsenoside Rh4 (Rh4) is one of the rare ginsenosides with higher pharmacological activity than ordinary ginsenosides, but its effect on alleviating AD and its molecular mechanism have not been studied. Here, we investigated the anti-AD effects of Rh4 and its potential mechanisms using an AD mouse model induced by a combination of AlCl3·6H2O and d-galactose. The results showed that Rh4 could significantly improve the ability of cognizance and reduce neuronal damage in mice. Concurrently, Rh4 attenuates amyloid β accumulation, increases the density of dendritic spines, and logically inhibits synaptic structural damage as a result of neuronal excessive apoptosis and autophagy. Rh4 can not only inhibit the inflammatory response caused by the overactivation of microglia and astrocytes, reduce the levels of pro-inflammatory factors, increase the level of antioxidant enzymes in serum, and significantly improve the activity of antioxidant enzyme SOD1 in the hippocampus but also inhibit the hyperphosphorylation of tau protein in the hippocampus of mice by regulating the Wnt2b/GSK-3β/SMAD4 signaling pathway. Together, this study provides a theoretical basis for Rh4 in the treatment of AD and reveals that Rh4 is a potential drug for the treatment of AD.

Natural Products as Modulators of Nrf2 Signaling Pathway in Neuroprotection

Neurodegenerative diseases (NDs) affect the West due to the increase in life expectancy. Nervous cells accumulate oxidative damage, which is one of the factors that triggers and accelerates neurodegeneration. However, cells have mechanisms that scavenge reactive oxygen species (ROS) and alleviate oxidative stress (OS). Many of these endogenous antioxidant systems are regulated at the gene expression level by the transcription factor Nrf2 (nuclear factor erythroid 2-related factor 2). In the presence of prooxidant conditions, Nrf2 translocates to the nucleus and induces the transcription of genes containing ARE (antioxidant response element). In recent years, there has been an increase in the study of the Nrf2 pathway and the natural products that positively regulate it to reduce oxidative damage to the nervous system, both in in vitro models with neurons and microglia subjected to stress factors and in vivo models using mainly murine models. Quercetin, curcumin, anthocyanins, tea polyphenols, and other less studied phenolic compounds such as kaempferol, hesperetin, and icariin can also modulate Nrf2 by regulating several Nrf2 upstream activators. Another group of phytochemical compounds that upregulate this pathway are terpenoids, including monoterpenes (aucubin, catapol), diterpenes (ginkgolides), triterpenes (ginsenosides), and carotenoids (astaxanthin, lycopene). This review aims to update the knowledge on the influence of secondary metabolites of health interest on the activation of the Nrf2 pathway and their potential as treatments for NDs.

Study on the Cellular Anti-Inflammatory Effect of Torularhodin Produced by Sporidiobolus pararoseus ZQHL Isolated from Vinegar Fungus

The red stretcher bacterium Sporidiobolus pararoseus is a high producer of carotenoids such as torularhodin, but its presence in vinegar has not been detected. Moreover, torularhodin has several biological activities, but its effect on the LPS-induced RAW 264.7 inflammatory cell model has also yet to be elucidated. In this study, S. pararoseus was identified in different vinegar samples from China by ITS sequencing. Meanwhile, one of the strains was deeply resolved by whole genome sequencing and functional annotation and named S. pararoseus ZQHL. Subsequently, the antioxidant effect of the fungal carotenoid torularhodin was investigated using in vitro DPPH, ABTS, and cellular models. Finally, LPS-induced RAW 264.7 cells were used as an inflammation model to assess torularhodin's protective effect on inflammatory cells and to determine whether the TLR4 pathway is associated with this process. The results indicate that torularhodin has good free radical scavenging ability in vitro and can contribute to cell viability. More importantly, torularhodin alleviated LPS-induced cellular inflammatory damage and reduced the expression of inflammatory factors such as TLR4, MyD88, and TNF-a. The mechanism may attenuate the cellular inflammatory response by inhibiting the TLR4 inflammatory pathway. In conclusion, torularhodin produced by S. pararoseus fungi in vinegar samples significantly scavenged free radicals in vitro and alleviated RAW 264.7 cellular inflammation by modulating the TLR4 pathway.

Natural inhibitors for acetylcholinesterase and autophagy modulators as effective antagonists for tau and β-amyloid in Alzheimer's rat model

Background: Phytochemicals have amazing biological effects in relation to age-related illnesses and are increasingly being studied in clinical trials. The goal of this study was to examine the effectiveness of the aqueous extracts of Rosmarinus officinalis L. (Rosemary) and Crocus sativus L. (Saffron) and their combinations as tau and β-amyloid antagonists in an Alzheimer's rat model. Methods: AlCl₃ and D-galactose (150 & 300 mg/kg) were used to create the Alzheimer's neuroinflammation rat model. The animals were subsequently given the two extracts and their combinations (500 mg/kg) along 15 days. The cognitive impairment, oxidative stress, tau & amyloid neuroproteins, acetylcholine, acetylcholinesterase neurotransmitters, proinflammatory cytokines, LC3 as an autophagy marker, computational analysis, and morphological alterations were all assessed. Results: When compared to the conventional donepezil and normal groups, the treated groups showed a significant improvement in all calculated parameters. The cortex and hippocampus have a better morphological appearance. In silico analysis found that these extracts may have an affinity for and impede the activity of some proteins thought to be essential regulators of disease progression. Conclusion: Rosemary and Saffron extracts by the power of their constituents were able to alleviate the neurotoxicity of AlCl₃ & D-galactose and regulate the natural autophagy process.

Torularhodin-Loaded Bilosomes Ameliorate Lipid Accumulation and Amino Acid Metabolism in Hypercholesterolemic Mice

SCOPE

Hypercholesterolemia is a cause of cardiovascular disease. Torularhodin is a carotenoid, and its entrapment in bilosomes helps to improve its bioavailability.

METHODS AND RESULTS

The effects of torularhodin-loaded bilosomes on lipid accumulation, inflammatory response, and serum metabolic profiles in hypercholesterolemic ApoE-/- C57BL/6J mice were investigated by feeding a high-fat, high-cholesterol diet (HFHCD) for 20 weeks. At the same time, mice were gavaged with torularhodin-loaded bilosomes for 10 weeks. The results showed that torularhodin successfully alleviated weight gain and insulin resistance in mice and could also lower blood lipids. Meanwhile, torularhodin improved liver lipid accumulation in mice and modulated inflammatory factors in the "blood-liver-ileum." Nontargeted metabolomics revealed that torularhodin significantly increased the concentrations of l-tryptophan, glyceraldehyde, hypotaurine, pyrophosphate, and niacinamide in serum (p < 0.01). In addition, targeted amino acid metabolomics verification found that torularhodin promoted the metabolism of serum amino acids in mice, particularly for branched-chain amino acids, thereby helping to improve hypercholesterolemia in mice. Finally, interaction network bioinformatics was used to demonstrate that amino acid metabolism represented an important mechanism by which torularhodin improves lipid accumulation and inflammatory response in mice.

CONCLUSIONS

Torularhodin can improve hypercholesterolemia in HFHCD-fed mice, thereby supporting the feasibility of its usage in food applications for cardiovascular disease prevention.

Nucleic acid drug vectors for diagnosis and treatment of brain diseases

Nucleic acid drugs have the advantages of rich target selection, simple in design, good and enduring effect. They have been demonstrated to have irreplaceable superiority in brain disease treatment, while vectors are a decisive factor in therapeutic efficacy. Strict physiological barriers, such as degradation and clearance in circulation, blood-brain barrier, cellular uptake, endosome/lysosome barriers, release, obstruct the delivery of nucleic acid drugs to the brain by the vectors. Nucleic acid drugs against a single target are inefficient in treating brain diseases of complex pathogenesis. Differences between individual patients lead to severe uncertainties in brain disease treatment with nucleic acid drugs. In this Review, we briefly summarize the classification of nucleic acid drugs. Next, we discuss physiological barriers during drug delivery and universal coping strategies and introduce the application methods of these universal strategies to nucleic acid drug vectors. Subsequently, we explore nucleic acid drug-based multidrug regimens for the combination treatment of brain diseases and the construction of the corresponding vectors. In the following, we address the feasibility of patient stratification and personalized therapy through diagnostic information from medical imaging and the manner of introducing contrast agents into vectors. Finally, we take a perspective on the future feasibility and remaining challenges of vector-based integrated diagnosis and gene therapy for brain diseases.

Neuroprotective effects of polysaccharide from Sparassis crispa on Alzheimer's disease-like mice: Involvement of microbiota-gut-brain axis

Alzheimer's disease (AD) is an irreversible neurodegenerative disease that may cause neurotoxicity and imbalance in gut microbiota. A polysaccharide derived from Sparassis crispa-1 (SCP-1) acts as a neuroprotective agent in vitro. There is, however, no clarity on the mechanism responsible for SCP-1's neuroprotective effects against AD. In this study, C57BL/6J male mice were treated with D-galactose and AlCl₃ to establish an animal model of AD, followed by treatment with SCP-1. As evidenced by behavioral tests and brain pathology, SCP-1 treatment ameliorated learning deficits and defective spatial recognition, reduced amyloidogenesis, and modulated the neurotransmitter levels (γ-aminobutyric acid, glutamate, and acetylcholine) in the brain of AD mice. The results of 16S rRNA sequencing revealed that SCP-1 reshaped the gut microbiota composition, especially by promoting the proliferation of butyrate-producing genera, such as Intestinaimonas, [Eubacterium] ventriosum group, Lachnospiraceae_UCG_010, and Lachnospiraceae_UCG_001, and suppressing the growth of inflammation-related bacteria (i.e., Escherichia/Shigella). Furthermore, SCP-1 significantly attenuated inflammation by reducing the levels of inflammatory cytokines, maintaining intestinal barrier function, inhibiting glial activation, and decreasing the expression of toll-like receptor 4 (TLR4) and nuclear factor-κB (NF-κB). Collectively, our findings suggest that SCP-1 may prevent the development of AD via modulation of gut microbiota and suppression of inflammation, for a potential application in preventing or managing AD.

The role of Nrf2 in protection against electrostatic field-induced oxidative stress and learning and memory decline in mice

The intensity of static electric field (SEF) in the surrounding environment of transmission lines has been greatly increased with the rapid development of ultra-high-voltage direct-current transmission. Therefore, the potential health effects of SEF have stimulated great public attention. It has been proven that SEF exposure can cause reversible damage to the nervous system through oxidative stress; however, the mechanism of its recovery is unclear. This study focused on nuclear factor erythroid 2-related factor 2 (Nrf2), a vital regulator of oxidative stress, and has been identified to notably impact the protection of organisms against many external stimuli. Herein, it was found that 56.3 kV/m SEF exposure for 7 days and 14 days significantly improved the expression levels of Nrf2 protein in the cytoplasm and nucleus of mice' hippocampus, as well as antioxidant genes, superoxide dismutase 2, and glutathione peroxidase 1. No significant difference in the expression level of the Nrf2 gene was found. The results indicated that the body could activate the Nrf2 signalling under SEF exposure by means other than up-regulation of Nrf2 gene expression. Inhibiting Nrf2 signalling by isoniazid could block SEF-induced gene transcription and protein expression, resulting in a decrease in antioxidant capacity, an increase in the level of lipid peroxide product, and irretrievability of learning and memory damage. These results demonstrated that the Nrf2 signalling pathway exhibited a protective role in SEF-induced oxidative damage and decline in learning and memory ability, which provides a potential strategy for preventing and treating SEF-related neurotoxicity.

Torularhodin Alleviates Hepatic Dyslipidemia and Inflammations in High-Fat Diet-Induced Obese Mice via PPARα Signaling Pathway

Torularhodin is a β-carotene-like compound from Sporidiobolus pararoseus, and its protective effect against high-fat diet (HFD)-induced hepatic dyslipidemia and inflammation was investigated. Compared to mice of C57BL/6J fed on HFD, the addition of Torularhodin into the HFD (HFD-T) significantly reduced body weight, serum triglyceride (TG), total cholesterol (TC), low-density lipoprotein (LDL), and the inflammatory mediators of TNF-α, IL-6, IL-1β, and lipopolysaccharide (LPS). A significant increase of high-density lipoprotein cholesterol (HDL-c), which is beneficial to cholesterol clearance, was also observed in HFD-T group. Proteomic analysis showed HDL-C-c is highly correlated with proteins (e.g., CPT1A and CYP7A1) involved in lipid β-oxidation and bile acid synthesis, whereas the other phenotypic parameters (TC, TG, LDL, and inflammatory cytokines) are highly associated with proteins (e.g., SLC27A4) involved in lipid-uptake. The up-regulated anti-inflammation proteins FAS, BAX, ICAM1, OCLN, GSTP1, FAF1, LRP1, APEX1, ROCK1, MANF, STAT3, and INSR and down-regulated pro-inflammatory proteins OPTN, PTK2B, FADD, MIF, CASP3, YAP1, DNM1L, and NAMPT not only demonstrate the occurrence of HFD-induced hepatic inflammation, but also prove the anti-inflammatory property of Torularhodin. KEGG signaling pathway analysis revealed that the PPARα signaling pathway is likely fundamental to the health function of Torularhodin through up-regulating genes related to fatty acid β-oxidation, cholesterol excretion, HDL-Cc formation, and anti-inflammation. Torularhodin, as a new food resource, may act as a therapeutic agent to prevent hepatic dyslipidemia and related inflammation for improved health.

Rhizoma Gastrodiae Water Extract Modulates the Gut Microbiota and Pathological Changes of P-TauThr231 to Protect Against Cognitive Impairment in Mice

Gastrodiae Rhizoma and its active constituents are known to exhibit neuroprotective effects in Alzheimer’s disease (AD). However, the effect of Rhizoma Gastrodiae water extract (WERG) on AD and the detailed mechanism of action remain unclear. In this study, the mechanism of action of WERG was investigated by the microbiome–gut–brain axis using a D-galactose (D-gal)/AlCl₃-induced AD mouse model. WERG improved the cognitive impairment of D-gal/AlCl₃-induced mice. The expression level of p-Tau^thr231 in the WERG-H treatment group was decreased, and p-Tau^thr231 was found negative in hippocampal DG, CA1, and CA3 regions. Here, the diversity and composition of the gut microbiota were analyzed by 16sRNA sequencing. WERG-H treatment had a positive correlation with Firmicutes, Bacilli, Lactobacillus johnsonii, Lactobacillus murinus, and Lactobacillus reuteri. Interestingly, the Rikenellaceae-RC9 gut group in the gut increased in D-gal/AlCl₃-induced mice, but the increased L. johnsonii, L. murinus, and L. reuteri reversed this process. This may be a potential mechanistic link between gut microbiota dysbiosis and P-Tau^Thr231 levels in AD progression. In conclusion, this study demonstrated that WERG improved the cognitive impairment of the AD mouse model by enriching gut probiotics and reducing P-Tau^Thr231 levels.

Nobiletin prevents amyloid β1-40-induced cognitive impairment via inhibition of neuroinflammation and oxidative/nitrosative stress

Alzheimer's disease (AD) is presented as an age-related neurodegenerative disease with multiple cognitive deficits and amyloid β (Aβ) accumulation is the most important involved factor in its development. Nobiletin is a bioflavonoid isolated from citrus fruits peels with anti-inflammatory and anti-oxidative activity as well as anti-dementia property that has shown potency to ameliorate intracellular and extracellular Ab. The aim of the present study was to assess protective effect of nobiletin against Aβ_1-40-induced cognitive impairment as a consistent model of AD. After bilateral intrahippocampal (CA1 subfield) injection of Aβ_1-40, rats were treated with nobiletin (10 mg/kg/day; p.o.) from stereotaxic surgery day (day 0) till day + 7. Cognition function was evaluated in a battery of behavioral tasks at week 3 with final assessment of hippocampal oxidative stress and inflammation besides Nissl staining and 3-nitrotyrosine (3-NT) immunohistochemistry. Analysis of behavioral data showed notable and significant improvement of alternation in Y maze test, discrimination ratio in novel object recognition task, and step through latency in passive avoidance test in nobiletin-treated Aβ group. Additionally, nobiletin treatment was associated with lower hippocampal levels of MDA and ROS and partial reversal of SOD activity and also improvement of Nrf2 with no significant effect on GSH and catalase. Furthermore, nobiletin attenuated hippocampal neuroinflammation in Aβ group as shown by lower tissue levels of TLR4, NF-kB, and TNFa. Histochemical findings showed that nobiletin prevents CA1 neuronal loss in Nissl staining in addition to its alleviation of 3-nitrotyrosine (3-NT) immunoreactivity as a marker of nitrosative stress. Collectively, these findings indicated neuroprotective and anti-dementia potential of nobiletin that is partly attributed to its anti-oxidative, anti-nitrosative, and anti-inflammatory property associated with proper modulation of TLR4/NF-kB/Nrf2 pathways.

"Cascaded Rocket" Nanosystems with Spatiotemporal Separation for Triple-Synergistic Therapy of Alzheimer's Disease

Alzheimer's disease (AD) remains an incurable disease due to the intricate pathogenesis. The neuropathological hallmarks include extracellular amyloid-β (Aβ) plaques, tau phosphorylation and extensive oxidative stress in neurons, which facilitate the progression of AD. Based on the complex etiology, a spatiotemporally "cascaded rocket" delivery system (DPH/TPGAS NPs) with metal ion/enzyme responses is established in this study for triple-synergistic AD treatment. After targeting and permeating the blood-brain barrier (BBB), the histidine units in the DPH chelate excess metal ions at the extracellular microenvironment, restraining the formation of Aβ aggregates, inducing the first-stage separation. Then, the remanent system targets neuronal cells and triggers the second separation with cathepsin B for reducing the level of phosphorylated tau and oxidative stress. Accordingly, the DPH/TPGAS NPs can achieve spatiotemporal drug release, which results in enhanced synergistic therapeutic effects both in the extracellular and intracellular region of the AD brain. After treating with DPH/TPGAS NPs, the memory deficits, levels of Aβ and phosphorylated tau, inflammation and neuron damages are remarkably ameliorated in 3 × Tg-AD mice. Therefore, this "cascaded rocket" delivery system has great potential to serve as a powerful platform and provides a new horizon to the therapeutic strategy for AD and other brain diseases' treatments.

Salidroside Ameliorates Alzheimer's Disease by Targeting NLRP3 Inflammasome-Mediated Pyroptosis

Amyloid β-protein (Aβ) is reported to activate NLRP3 inflammasomes and drive pyroptosis, which is subsequently involved in the pathogenesis of neurodegenerative diseases, such as Alzheimer's disease (AD). To date, the pathogenesis of AD is unfortunately insufficiently elucidated. Therefore, this study was conducted to explore whether Salidroside (Sal) treatment could benefit AD by improving pyroptosis. Firstly, two animal models of AD, induced, respectively, by Aβ1-42 and D-galactose (D-gal)/AlCl₃, have been created to assist our appreciation of AD pathophysiology. We then confirmed that pyroptosis is related to the pathogenesis of AD, and Sal can slow the progression of AD by inhibiting pyroptosis. Subsequently, we established the D-gal and Nigericin-induced PC12 cells injury model in vitro to verify Sal blocks pyroptosis mainly by targeting the NLRP3 inflammasome. For in vivo studies, we observed that Aβ accumulation, Tau hyperphosphorylation, neurons of hippocampal damage, and cognitive dysfunction in AD mice, caused by bilateral injection of Aβ1-42 into the hippocampus and treatments with D-gal combine AlCl₃. Besides, accumulated Aβ promotes NLRP3 inflammasome activation, which leads to the activation and release of a pro-inflammatory cytokine, interleukin-1 beta (IL-1β). Notably, both Aβ accumulation and hyperphosphorylation of Tau decreased and inhibited pyroptosis by downregulating the expression of IL-1β and IL-18, which can be attributed to the treatment of Sal. We further found that Sal can reverse the increased protein expression of TLR4, MyD88, NF-κB, P-NF-κB, NLRP3, ASC, cleaved Caspase-1, cleaved GSDMD, IL-1β, and IL-18 in vitro. The underlying mechanism may be through inhibiting TLR4/NF-κB/NLRP3/Caspase-1 signaling pathway. Our study highlights the importance of NLRP3 inflammasome-mediated pyroptosis in AD, and how the administration of pharmacological doses of Sal can inhibit NLRP3 inflammasome-mediated pyroptosis and ameliorate AD. Thus, we conclude that NLRP3 inflammasome-mediated pyroptosis plays a significant role in AD and Sal could be a therapeutic drug for AD.

Protective effects of hydroxy-α-sanshool from the pericarp of Zanthoxylum bungeanum Maxim. On D-galactose/AlCl3-induced Alzheimer's disease-like mice via Nrf2/HO-1 signaling pathways

Hydroxy-α-sanshool (HAS) is an unsaturated fatty acid amide from Zanthoxylum bungeanum Maxim. with hypolipidemic, hypoglycemic, anti-inflammatory, and neurotrophic effects, etc. In this study, results indicated that HAS effectively ameliorated spontaneous locomotion deficit of mice induced by D-galactose (D-gal) and AlCl₃ treatment in open field test. Results of Morris water maze test (MWM) showed that HAS significantly improved the spatial learning and memory ability of aging mice. Histopathological evaluations revealed that HAS markedly alleviated morphological changes and increased number of Nissl neurons in hippocampus of D-gal/AlCl₃-induced Alzheimer's disease (AD)-like mice. HAS markedly reduced malondialdehyde (MDA) production, and increased the activity of antioxidative enzymes including superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT), showing an inhibitory effect on oxidative stress. Furthermore, HAS treatment obviously reversed the inhibitory expressions of mRNA and protein of HO-1 and Nrf2 in the hippocampus of AD mice, suggesting that neuroprotective effects of HAS against oxidative stress might be mediated by the Nrf2/HO-1 pathway. Meanwhile, HAS significantly inhibited neuronal apoptosis by decreasing mRNA and protein expressions of Cyt-c, Bax and Caspase 3, and increasing Bcl-2 expression in the hippocampus of AD mice. These results suggest that HAS have the potential to be developed as antioxidant drug for the prevention and early therapy of AD.

The impact of the physical form of torularhodin on its metabolic fate in the gastrointestinal tract

Torularhodin is a fungal carotenoid with multiple health benefits. However, the relationship between its physical form and metabolic fate in the gastrointestinal tract (GIT), which is essential to its bioavailability and health efficacy, has rarely been studied. Thus, physical forms of torularhodin including nanoemulsion powder (T-EP), capsules of the T-EP by alginate (T-EPA), and solution in MCT oil (T-oil) were used in the study. T-EP was produced through OSA-starch-mediated torularhodin emulsification and spray drying whereas the T-EPA was alginate-based capsules of the T-EP particles that were entrapped in the network structure of the alginate matrix as observed by scanning electron microscopy (SEM). The oil digestibility in the simulated small intestine was decreased from T-EP (100%), T-oil (60%) to T-EPA (40%), and the bioaccessibilities were 27%, 15% and 12%, respectively. The in vivo study using mice revealed that the content of torularhodin gradually decreased along with the digestion time in both the stomach and small intestine while a significantly higher colonic accumulation was observed in T-EPA compared to T-oil and T-EP. In vitro fecal fermentation showed that propionate (32 mM) was the predominant metabolite produced by torularhodin in the physical form of T-EPA. Thus, the physical form of torularhodin is a significant contributing factor to its GIT metabolic fate, and a health outcome-oriented design of the physical form of torularhodin or other nutraceuticals is beneficial for the development of functional foods with enhanced health benefits.

Transcriptomic and Metabolomic Analyses Provide Insights into the Enhancement of Torulene and Torularhodin Production in Rhodotorula glutinis ZHK under Moderate Salt Conditions

Carotenoids are a group of tetraterpene pigments widely used in the food, pharmaceutical, and cosmetic industries. Torulene, torularhodin, and β-carotene, three principal carotenoids synthesized by Rhodotorula glutinis ZHK, possess strong health-promoting properties such as antioxidant, provitamin A, and antitumor. Here, the effect of different salt conditions on carotenoids production of R. glutinisZHK was investigated. The results showed that the total carotenoids were significantly enhanced in 0.5 M (3.91 mg/L) and 0.75 M (5.41 mg/L) NaCl treatments than that in 1.0 M (0.35 mg/L) and control (1.42 mg/L) after 120 h of cultivation. Of which, the increase in torulene and torularhodin production acts as the main contributor to the enhancement of total carotenoids. Transcriptome profiling revealed that salt stress efficiently promotes the gene expression of crtI, which could explain the molecular mechanisms of the enhanced torulene and torularhodin production under salt stress. Further experiments indicated that torulene and torularhodin play an important role in quenching excrescent reactive oxygen species induced by salt stress. Together, the present study reports an effective strategy for simultaneously improving torulene and torularhodin production in R. glutinis ZHK.