Neuroprotective potential of fisetin in an experimental model of spinal cord injury: via modulation of NF-κB/IκBα pathway

Mechanisms of nitric oxide in spinal cord injury

Spinal cord injury (SCI) is a primary lesion of the spinal cord that results from external forces or diseases, accompanied by a cascade of secondary events. Nitric oxide, an endogenous gas that functions as a signaling molecule in the human body, plays a crucial role in vasodilation of smooth muscles, regulation of blood flow and pressure, and inflammatory response. This article provides a comprehensive overview of the involvement of nitric oxide in SCI and highlights recent advances in basic research on pharmacological agents that inhibit nitric oxide elevation after SCI, offering valuable insights for future therapeutic interventions targeting SCI.

Fisetin Promotes Functional Recovery after Spinal Cord Injury by Inhibiting Microglia/Macrophage M1 Polarization and JAK2/STAT3 Signaling Pathway

Spinal cord injury (SCI) is one of the most serious health problems, with no effective therapy. Recent studies indicate that Fisetin, a natural polyphenolic flavonoid, exhibits multiple functions, such as life-prolonging, antioxidant, antitumor, and neuroprotection. However, the restorative effects of Fisetin on SCI and the underlying mechanism are still unclear. In the present study, we found that Fisetin reduced LPS-induced apoptosis and oxidative damage in PC12 cells and reversed LPS-induced M1 polarization in BV2 cells. Additionally, Fisetin safely and effectively promoted the motor function recovery of SCI mice by attenuating neurological damage and promoting neurogenesis at the lesion. Moreover, Fisetin administration inhibited glial scar formation, modulated microglia/macrophage polarization, and reduced neuroinflammation. Network pharmacology, RNA-seq, and molecular biology revealed that Fisetin inhibited the activation of the JAK2/STAT3 signaling pathway. Notably, Colivelin TFA, an activator of JAK2/STAT3 signaling, attenuated Fis-mediated neuroinflammation inhibition and therapeutic effects on SCI mice. Collectively, Fisetin promotes functional recovery after SCI by inhibiting microglia/macrophage M1 polarization and the JAK2/STAT3 signaling pathway. Thus, Fisetin may be a promising therapeutic drug for the treatment of SCI.

Fisetin-loaded pluronic-based nanogel: Radiation synthesis for alleviating neurocognitive impairments in a rat model of alzheimer's disease via modulation of the apoptotic cascade

Alzheimer's disease (AD) is a neurodegenerative disorder marked by cognitive impairment and memory loss. In this study, AD was experimentally induced in rats using aluminum chloride (AlCl3) and D-galactose (D-gal). Fisetin (Fis), a natural compound with antioxidant and anti-inflammatory properties, has potential for neurodegeneration management, but its low bioavailability limits clinical applications. To address this, we synthesized and characterized Pluronic-2-Acrylamido-2-methylpropane sulfonic acid (PLUR-PAMPS) nanogels using gamma radiation and successfully loaded Fis onto them (Fis-PLUR-PAMPS). The optimal formulation exhibited minimal particle size, a highly acceptable polydispersity index, and the highest zeta-potential, enhancing stability and solubilization efficiency. Our goal was to improve Fis's bioavailability and assess its efficacy against AlCl3/D-gal-induced AD. Male albino Wistar rats were pre-treated orally with Fis (40 mg/kg) or Fis-PLUR-PAMPS for seven days, followed by a seven-day intraperitoneal injection of AlCl3 and D-gal. Behavioral assessments, histopathological analysis, and biochemical evaluation of markers related to AD pathology were conducted. Results demonstrated that Fis-PLUR-PAMPS effectively mitigated cognitive impairments and neurodegenerative signs induced by AlCl3/D-gal. These findings suggest that Fis-PLUR-PAMPS nanogels enhance Fis's bioavailability and therapeutic efficacy, offering a promising approach for AD management.

Fisetin attenuates arsenic and fluoride subacute co-exposure induced neurotoxicity via regulating TNF-α mediated activation of NLRP3 inflammasome

Groundwater is considered safe, however, the occurrence of contaminants like arsenic and fluoride has raised a major healthcare concern. Clinical studies suggested that arsenic and fluoride co-exposure induced neurotoxicity, however efforts to explore safe and effective management of such neurotoxicity are limited. Therefore, we investigated the ameliorative effect of Fisetin against arsenic and fluoride subacute co-exposure-induced neurotoxicity, and associated biochemical and molecular changes. Male BALB/c mice Arsenic (NaAsO₂: 50mg/L) and fluoride (NaF: 50mg/L) were exposed to drinking water and fisetin (5, 10, and 20mg/kg/day) was administered orally for 28 days. The neurobehavioral changes were recorded in the open field, rotarod, grip strength, tail suspension, forced swim, and novel object recognition test. The co-exposure resulted in anxiety-like behaviour, loss of motor coordination, depression-like behaviour, and loss of novelty-based memory, along with enhanced prooxidant, inflammatory markers and loss of cortical and hippocampal neurons. The treatment with fisetin reversed the co-exposure-induced neurobehavioral deficit along with restoration of redox & inflammatory milieu, and cortical and hippocampal neuronal density. Apart from antioxidants, inhibition of TNF-α/ NLRP3 expression has been suggested as one of the plausible neuroprotective mechanisms of Fisetin in this study.

Flavonols in Action: Targeting Oxidative Stress and Neuroinflammation in Major Depressive Disorder

Major depressive disorder is one of the most common mental illnesses that highly impairs quality of life. Pharmacological interventions are mainly focused on altered monoamine neurotransmission, which is considered the primary event underlying the disease's etiology. However, many other neuropathological mechanisms that contribute to the disease's progression and clinical symptoms have been identified. These include oxidative stress, neuroinflammation, hippocampal atrophy, reduced synaptic plasticity and neurogenesis, the depletion of neurotrophic factors, and the dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis. Current therapeutic options are often unsatisfactory and associated with adverse effects. This review highlights the most relevant findings concerning the role of flavonols, a ubiquitous class of flavonoids in the human diet, as potential antidepressant agents. In general, flavonols are considered to be both an effective and safe therapeutic option in the management of depression, which is largely based on their prominent antioxidative and anti-inflammatory effects. Moreover, preclinical studies have provided evidence that they are capable of restoring the neuroendocrine control of the HPA axis, promoting neurogenesis, and alleviating depressive-like behavior. Although these findings are promising, they are still far from being implemented in clinical practice. Hence, further studies are needed to more comprehensively evaluate the potential of flavonols with respect to the improvement of clinical signs of depression.

Mechanistic insight into the protective effects of fisetin against arsenic-induced reproductive toxicity in male rats

Arsenic is one of the most hazardous environmental contaminants, which adversely affects the dynamics of male reproductive system. Fisetin (FIS) is a bioactive flavonoid, which is known to exert strong antioxidative effects. Therefore, the current research was planned to evaluate the alleviative efficacy of FIS against arsenic-induced reproductive damages. Forty-eight male albino rats were divided into 4 groups (n = 12), which were treated as follows: (1) Control, (2) Arsenic-intoxicated group (8 mg kg^-1), (3) Arsenic + FIS-treated group (8 mg kg^-1 + 10 mg kg^-1), and (4) FIS-treated group (10 mgkg^-1). After 56 days of treatment, the biochemical, lipidemic, steroidogenic, hormonal, spermatological, apoptotic and histoarchitectural profiles of rats were analyzed. Arsenic intoxication reduced the enzymatic activities of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GSR), in addition to glutathione (GSH) level. Conversely, the levels of thiobarbituric acid reactive substance (TBARS) and reactive oxygen species (ROS) were increased. Moreover, it escalated the level of low-density lipoprotein (LDL), triglycerides and total cholesterol, while declining the level of high-density lipoprotein (HDL). Furthermore, steroidogenic enzymes expressions, 3β-hydroxysteroid dehydrogenase (HSD), 17β-HSD, steroidogenic acute regulatory protein (StAR), cholesterol side-chain cleavage enzyme (CYP11A1) and 17α-hydroxylase/17, 20-lyase (CYP17A1), were found to be reduced, which brought down the level of testosterone. Besides, the levels of gonadotropins (LH and FSH) were decreased. Additionally, a decline in sperm mitochondrial membrane potential (MMP), motility, epididymal sperm count and hypo-osmotic swelling (HOS) coil-tailed sperms was observed, whereas the dead sperms and structural damages (head, midpiece and tail) of sperms were escalated. Moreover, arsenic exposure up-regulated the mRNA expressions of apoptotic markers, namely Bax and caspase-3, whereas lowered the expression of anti-apoptotic marker, Bcl-2. In addition, it induced histoarchitectural changes in testes of rats. However, FIS treatment resulted in remarkable improvements in testicular and sperm parameters. Therefore, it was inferred that FIS could serve as a therapeutic candidate against arsenic-generated male reproductive toxicity attributing to its anti-oxidant, anti-lipoperoxidative, anti-apoptotic, and androgenic efficacy.

Evaluation of fisetin as a potential inducer of mitochondrial biogenesis in SH-SY5Y neuronal cells

Objectives

Increasing evidence implicates impaired mitochondrial biogenesis as an important contributor to mitochondrial dysfunction, which plays a central role in the pathogenesis of neurodegenerative diseases including Parkinson's disease (PD). For this reason, targeting mitochondrial biogenesis may present a promising therapeutic strategy for PD. The present study attempted to investigate the effects of fisetin, a dietary flavonoid, on mitochondrial biogenesis and the expression of PD-associated genes in neuronal cells.

Materials and Methods

The effects of fisetin on mitochondrial biogenesis were evaluated by three different approaches; PGC-1α and TFAM mRNA expressions by RT-qPCR, mitochondrial DNA (mtDNA) content by quantitative PCR and mitochondrial mass by MitoTracker staining. Next, a PCR array was performed to evaluate the effects of fisetin on the expression profile of PD-associated genes. Finally, the common targets of fisetin and PD were analyzed by in silico analyses.

Results

The results demonstrated that fisetin treatment can increase PGC-1α and TFAM mRNA levels, mtDNA copy number, and mitochondrial mass in neuronal cells. Fisetin also altered the expressions of some PD-related genes involved in neuroprotection and neuronal differentiation. Moreover, the bioinformatics analyses suggested that the AKT1-GSK3B signaling might be responsible for the potential neuroprotective effects of fisetin.

Conclusion

Collectively, these results imply that fisetin could modulate some neuroprotective mechanisms including mitochondrial biogenesis, and may serve as a potential drug candidate for PD.

Discovering the Effects of Fisetin on NF-κB/NLRP-3/NRF-2 Molecular Pathways in a Mouse Model of Vascular Dementia Induced by Repeated Bilateral Carotid Occlusion

Vascular dementia (VaD) is the second leading cause of dementia. The majority of VaD patients have cognitive abnormalities, which are caused by cerebral hypoperfusion-induced ischemia, endothelial dysfunction, oxidative stress, and neuroinflammation. Natural products are receiving increasing attention for the treatment of neuroinflammatory diseases. The aim of this study was to investigate the molecular pathways underlying the protective effects of fisetin, a flavonoid present in many fruits and vegetables, in a mouse model of VaD induced by repeated ischemia-reperfusion (IR) of the total bilateral carotid artery. Here, we found that VaD caused brain injury, lipid peroxidation, and neuronal death in the hippocampus, as well as astrocyte and microglial activation, and reduced BDNF neurotrophic factor expression together with behavioral alterations. In addition, VaD induced the activation of inflammasome components (NLRP-3, ASC, and caspase 1), and their downstream products (IL-1β and IL-18) release and promote activation of apoptotic cell death. Fisetin attenuated histological injury, malondialdehyde levels, inflammasome pathway activation, apoptosis, as well as increased BDNF expression, reduced astrocyte, microglial activation, and cognitive deficits. In conclusion, the protective effects of fisetin could be due to the inhibition of the ROS-induced activation of NF-κB/NLRP3 inflammasome together with the activation of antioxidant Nrf2/HO-1, suggesting a possible crosstalk between these molecular pathways.

The Involvement of Caspases in Neuroinflammation and Neuronal Apoptosis in Chronic Pain and Potential Therapeutic Targets

Chronic pain is a common, complex and unpleasant sensation following nerve injury, tissue trauma, inflammatory diseases, infection and cancer. It affects up to 25% of adults and is increasingly recognized as the leading cause of distress, disability and disease burden globally. Chronic pain is often refractory to most current analgesics, thus emphasizing the requirement for improved therapeutic medications. It is of great importance to elucidate the specific pathogenesis of chronic pain with different etiologies. Recent progress has advanced our understanding in the contribution of neuroinflammation and glial cells (microglia and astrocyte) activation in the plasticity of excitatory nociceptive synapses and the development of chronic pain phenotypes. Oxidative stress-associated neuronal apoptosis is also identified to be a pivotal step for central pain sensitization. The family of cysteine aspartate specific proteases (Caspases) has been well known to be key signaling molecules for inflammation and apoptosis in several neurological conditions. Recent studies have highlighted the unconventional and emerging role of caspases in microgliosis, astrocytes morphogenesis, chemokines release, cytokines secretion and neuronal apoptosis in initiating and maintaining synaptogenesis, synaptic strength and signal transduction in persistent pain hypersensitivity, suggesting the possibility of targeting caspases pathway for prevention and treatment of chronic pain. In this review, we will discuss and summarize the advances in the distinctive properties of caspases family in the pathophysiology of chronic pain, especially in neuropathic pain, inflammatory pain, cancer pain and musculoskeletal pain, with the aim to find the promising therapeutic candidates for the resolution of chronic pain to better manage patients undergoing chronic pain in clinics.

Fisetin, potential flavonoid with multifarious targets for treating neurological disorders: An updated review

Neurodegenerative disorders pose a significant health burden and imprint a debilitative impact on the quality of life. Importantly, aging is intricately intertwined with the progression of these disorders, and their prevalence increases with a rise in the aging population worldwide. In recent times, fisetin emerged as one of the potential miracle molecules to address neurobehavioral and cognitive abnormalities. These effects were attributed to its actions on several macromolecules and multiple molecular mechanisms. Fisetin belongs to a class of flavonoids, which is found abundantly in several fruits and vegetables. Fisetin has manifested several health benefits in preclinical models of neurodegenerative diseases such as Alzheimer's disease, Vascular dementia, and Schizophrenia. Parkinson's disease, Amyotrophic Lateral Sclerosis, Huntington's disease, Stroke, Traumatic Brain Injury (TBI), and age-associated changes. This review aimed to evaluate the potential mechanisms and pharmacological effects of fisetin in treating several neurological diseases. This review also provides comprehensive data on up-to-date recent literature and highlights the various mechanistic pathways pertaining to fisetin's neuroprotective role.