Sulforaphane inhibits the production of Aβ partially through the activation of Nrf2-regulated oxidative stress

Sulforaphane: An emerging star in neuroprotection and neurological disease prevention

Neurological diseases, including both acute injuries and chronic neurodegenerative disorders, represent major contributors to morbidity and mortality worldwide. Chronic neurodegenerative diseases, such as Alzheimer's disease (AD) and Parkinson's disease (PD), which require long-term management, present significant challenges in the search for neuroprotective agents with reduced adverse effects and enhanced therapeutic efficacy. Sulforaphane (SFN), a bioactive compound found in cruciferous vegetables like broccoli and cauliflower, has garnered considerable attention for its potent neuroprotective properties and overall health benefits. Marketed primarily as a dietary supplement, SFN has shown a variety of biological activities and therapeutic potential in neurological diseases. Recent surging studies including ours have highlighted its ability to impede the progression of AD, PD, and cerebral ischemia by fostering neurogenesis and inhibiting apoptosis, oxidative stress, and neuroinflammation. This review aims to summarize the latest research on SFN, exploring its advanced therapeutic potential and underlying mechanisms in various neurological diseases, offering a comprehensive overview for researchers focused on neurological pathogenesis and drug development in neuroprotection.

Avicularin inhibits ferroptosis and improves cognitive impairments in Alzheimer's disease by modulating the NOX4/Nrf2 axis

BACKGROUND

Alzheimer's disease (AD) is a widespread neurodegenerative disorder for which effective therapies remain elusive, primarily due to the complexity of its underlying pathophysiology. In recent years, natural products have gained attention for their therapeutic potential in AD, owing to their multi-targeted actions and low toxicity profiles. Avicularin (Avi), a flavonoid derived from the peels of Zanthoxylum bungeanum Maxim., has shown promise as an anti-AD agent. However, the specific mechanisms by which Avi mitigates oxidative stress and inhibits ferroptosis in AD models remain insufficiently understood. Further investigation is required to elucidate its therapeutic potential in these pathways.

PURPOSE

Therefore, this study aims to elucidate the neuroprotective effects of Avi in AD by investigating its impact on the NOX4/Nrf2 signaling pathway, as well as its role in modulating oxidative stress and ferroptosis.

METHODS

In this study, an in vitro H2O2-induced oxidative stress model in SH-SY5Y cells was utilized to evaluate the pharmacological efficacy and underlying mechanisms of Avi. Molecular docking, cellular thermal shift assay and bio-layer interferometry assays were conducted to identify potential molecular targets of Avi. Additionally, in vivo models, including scopolamine (SCOP)-induced and APP/PS1 transgenic mice, were employed to assess the cognitive effects of Avi and further explore its associated molecular mechanisms.

RESULTS

Our study demonstrates that Avi effectively attenuates H2O2-induced toxicity in SH-SY5Y cells by reducing apoptosis and enhancing cellular antioxidant defenses. This neuroprotective effect is mediated through the inhibition of NOX4 and the promotion of Nrf2 nuclear translocation. Furthermore, Avi improves cognitive function and mitigates ferroptosis in both SCOP-induced and APP/PS1 transgenic mouse models of AD.

CONCLUSION

Avi emerges as an effective neuroprotective agent against AD, offering a promising therapeutic approach by targeting the NOX4/Nrf2 signaling axis to alleviate oxidative stress and ferroptosis.

The role of isothiocyanate-rich plants and supplements in neuropsychiatric disorders: a review and update

Neuroinflammation in response to environmental stressors is an important common pathway in a number of neurological and psychiatric disorders. Responses to immune-mediated stress can lead to epigenetic changes and the development of neuropsychiatric disorders. Isothiocyanates (ITC) have shown promise in combating oxidative stress and inflammation in the nervous system as well as organ systems. While sulforaphane from broccoli is the most widely studied ITC for biomedical applications, ITC and their precursor glucosinolates are found in many species of cruciferous and other vegetables including moringa. In this review, we examine both clinical and pre-clinical studies of ITC on the amelioration of neuropsychiatric disorders (neurodevelopmental, neurodegenerative, and other) from 2018 to the present, including documentation of protocols for several ongoing clinical studies. During this time, there have been 16 clinical studies (9 randomized controlled trials), most of which reported on the effect of sulforaphane on autism spectrum disorder and schizophrenia. We also review over 80 preclinical studies examining ITC treatment of brain-related dysfunctions and disorders. The evidence to date reveals ITC have great potential for treating these conditions with minimal toxicity. The authors call for well-designed clinical trials to further the translation of these potent phytochemicals into therapeutic practice.

Thioredoxin (Trx): A redox target and modulator of cellular senescence and aging-related diseases

Thioredoxin (Trx) is a compact redox-regulatory protein that modulates cellular redox state by reducing oxidized proteins. Trx exhibits dual functionality as an antioxidant and a cofactor for diverse enzymes and transcription factors, thereby exerting influence over their activity and function. Trx has emerged as a pivotal biomarker for various diseases, particularly those associated with oxidative stress, inflammation, and aging. Recent clinical investigations have underscored the significance of Trx in disease diagnosis, treatment, and mechanistic elucidation. Despite its paramount importance, the intricate interplay between Trx and cellular senescence-a condition characterized by irreversible growth arrest induced by multiple aging stimuli-remains inadequately understood. In this review, our objective is to present a comprehensive and up-to-date overview of the structure and function of Trx, its involvement in redox signaling pathways and cellular senescence, its association with aging and age-related diseases, as well as its potential as a therapeutic target. Our review aims to elucidate the novel and extensive role of Trx in senescence while highlighting its implications for aging and age-related diseases.

Cellular Stress Response (Hormesis) in Response to Bioactive Nutraceuticals with Relevance to Alzheimer Disease

Significance: Alzheimer's disease (AD) is the most common form of dementia associated with aging. As the large Baby Boomer population ages, risk of developing AD increases significantly, and this portion of the population will increase significantly over the next several decades. Recent Advances: Research suggests that a delay in the age of onset by 5 years can dramatically decrease both the incidence and cost of AD. In this review, the role of nuclear factor erythroid 2-related factor 2 (Nrf2) in AD is examined in the context of heme oxygenase-1 (HO-1) and biliverdin reductase-A (BVR-A) and the beneficial potential of selected bioactive nutraceuticals. Critical Issues: Nrf2, a transcription factor that binds to enhancer sequences in antioxidant response elements (ARE) of DNA, is significantly decreased in AD brain. Downstream targets of Nrf2 include, among other proteins, HO-1. BVR-A is activated when biliverdin is produced. Both HO-1 and BVR-A also are oxidatively or nitrosatively modified in AD brain and in its earlier stage, amnestic mild cognitive impairment (MCI), contributing to the oxidative stress, altered insulin signaling, and cellular damage observed in the pathogenesis and progression of AD. Bioactive nutraceuticals exhibit anti-inflammatory, antioxidant, and neuroprotective properties and are potential topics of future clinical research. Specifically, ferulic acid ethyl ester, sulforaphane, epigallocatechin-3-gallate, and resveratrol target Nrf2 and have shown potential to delay the progression of AD in animal models and in some studies involving MCI patients. Future Directions: Understanding the regulation of Nrf2 and its downstream targets can potentially elucidate therapeutic options for delaying the progression of AD. Antioxid. Redox Signal. 38, 643-669.

Modulatory Role of Curcumin on Cobalt-Induced Memory Deficit, Hippocampal Oxidative Damage, Astrocytosis, and Nrf2 Expression

Chemical overexposure is a growing environmental risk factor for many medical issues. Cobalt toxicity from environmental, industrial, and medical exposure has previously been linked to neurological impairment. Hence, the current study looked into the neuroprotective potential of curcumin, a natural polyphenol contained in the spice turmeric, against cobalt-induced neurotoxicity. Adult rats were randomly divided into six groups as follows: control, 40 mg/kg cobalt chloride (CoCl₂) only, 240 mg/kg curcumin only, 120 mg/kg or 240 mg/kg curcumin, or 100 mg/kg vitamin C co-administered with CoCl₂. The administration was via oral route daily for 4 weeks. After that, neurobehavioral tests were undertaken to evaluate short-term spatial memory. Biochemical investigation was performed to determine the hippocampal levels of status via measures of SOD, CAT, GST, and LPO. Furthermore, immunohistochemical assessment of the expression of GFAP and Nrf2 in the hippocampus was carried out. In the CoCl₂ group, the results showed altered behavioral responses, a decrease in antioxidant activities, increased expression of GFAP and the number of activated astrocytes, and decreased immunoexpression of Nrf2. These effects were mitigated in the curcumin- and vitamin C-treated groups. These results collectively imply that curcumin enhances memory functions in rats exposed to cobalt possibly by attenuating oxidative responses, mitigating astrocytosis, and modulating Nrf2 signaling.

Iron dyshomeostasis and ferroptosis in Alzheimer’s disease: Molecular mechanisms of cell death and novel therapeutic drugs and targets for AD

Alzheimer’s disease (AD) is a degenerative disease of the central nervous system that is the most common type of senile dementia. Ferroptosis is a new type of iron-dependent programmed cell death identified in recent years that is different from other cell death forms. Ferroptosis is induced by excessive accumulation of lipid peroxides and reactive oxygen species (ROS) in cells. In recent years, it has been found that ferroptosis plays an important role in the pathological process of AD. Iron dyshomeostasis contribute to senile plaques (SP) deposition and neurofibrillary tangles (NFTs). Iron metabolism imbalance in brain and the dysfunction of endogenous antioxidant systems including system Xc- and glutathione peroxidase (GPX) are closely related to the etiopathogenesis of AD. Dysfunction of nuclear receptor coactivator 4 (NCOA4)-mediated ferritinophagy induced ferroptosis can accelerates the pathological process of AD. In addition, NRF2, through regulating the expression of a considerable number of genes related to ferroptosis, including genes related to iron and glutathione metabolism, plays an important role in the development of AD. Here, we review the potential interaction between AD and ferroptosis and the major pathways regulating ferroptosis in AD. We also review the active natural and synthetic compounds such as iron chelators, lipid peroxidation inhibitors and antioxidants available to treat AD by alleviating iron dyshomeostasis and preventing ferroptosis in mice and cell models to provide valuable information for the future treatment and prevention of AD.

Biphasic effect of sulforaphane on angiogenesis in hypoxia via modulation of both Nrf2 and mitochondrial dynamics

Sulforaphane (SFN) is an isothiocyanate (ITC) derived from a glucosinolate, glucoraphinin found in cruciferous vegetables. There are few studies that focus on the role of SFN in angiogenesis under hypoxic conditions. The effect of SFN on angiogenesis and the underlying mechanisms including the roles of Nrf2 and mitochondrial dynamics were investigated using cultured human umbilical vein endothelial cells (HUVECs) in hypoxia. SFN at low doses (1.25-5 μM) increased hypoxia-induced HUVEC migration and tube formation, and alleviated hypoxia-induced retarded proliferation, but high doses (≥10 μM) exhibited an opposite effect. Under hypoxia, the expression of Nrf2 and heme oxygenase-1 was up-regulated by SFN treatment. Nrf2 knockdown abrogated SFN (2.5 μM)-induced tube formation and further potentiated the inhibitory effect of SFN (10 μM) on angiogenesis. Meanwhile, the mitochondrial function, morphology and expression of dynamic-related proteins suggested that low-dose SFN protected against hypoxia-induced mitochondrial injury and alleviated hypoxia-induced fission Nrf2-dependently without affecting the expression of key effector proteins (Drp1, Fis1, Mfn1/2 and Opa1), while high concentrations (≥10 μM SFN) aggravated hypoxia-induced mitochondrial injury, fission and Drp1 expression, and inhibited Mfn1/2 expression. These findings suggest that SFN biphasically affected the angiogenic capacity of hypoxia challenged HUVECs potentially via mechanisms involving an integrated modulation of Nrf2 and mitochondrial dynamics.