Neuroprotective effect of quercetin against radiation-induced endoplasmic reticulum stress in neurons

An unmet need for pharmacology: Treatments for radiation-induced gastrointestinal mucositis

Gastrointestinal mucositis (GIM) continues to be a significant issue in the management of abdominal cancer radiation treatments and chemotherapy, causing significant patient discomfort and therapy interruption or even cessation. This review will first focus on radiotherapy induced GIM, providing an understanding of its clinical landscape. Subsequently, the aetiology of GIM will be reviewed, highlighting diverse contributing factors. The cellular and tissue damage and associated molecular responses in GIM will be summarised in the context of the underlying complex biological processes. Finally, available drugs and pharmaceutical therapies will be evaluated, underscoring their insufficiency, and highlighting the need for further research and innovation. This review will emphasize the urgent need for improved pharmacologic therapeutics for GIM, which is a key research priority in oncology.

A novel approach of using Maca root as a radioprotector in a rat testicular damage model focusing on GRP78/CHOP/Caspase-3 pathway

PURPOSE

Despite the effectiveness of ionizing radiation in treating cancer, it can damage healthy tissues in the vicinity. Due to the high radio-sensitivity of testicular tissues, radiation therapy may affect spermatogenesis, which may result in infertility. Hence, in this study testicular damage model is constructed to investigate the mitigation effect of Maca root powder and its potential radioprotective activity through both oxidative and endoplasmic reticulum (ER) stresses, besides the apoptotic pathway.

METHODS

Male albino rats were exposed to 6Gy of whole-body gamma radiation single dose. Maca root powder (1 g/kg b.wt./day, by oral gavage) was administered for a week before irradiation, then d-galactose (300 mg/kg, by oral gavage) and Maca daily for another week.

RESULTS

Gamma radiation and d-galactose revealed a significant decrease in serum testosterone, sperm count, and motility and higher percentage of the sperm head abnormality, while Maca root treatment maintained all sperm morphology parameters. Maca root treatment demonstrated a notable defense against radiation-induced oxidative stress and ameliorated malonaldehyde (MDA), reactive oxygen species (ROS), nitric oxide (NO), glutathione-S-transferase (GST) levels, reduced glutathione (GSH), oxidized glutathione (GSSG) and the ratio of GSH/GSSG in testis tissues. Exposure to gamma rays and d-galactose displayed a significant elevation in GRP78, CHOP, total caspase-3 as well as active (cleaved) caspase-3 levels, whereas treatment with Maca significantly reduced the ER and apoptotic markers levels. Also, Maca improved the histological changes of the disorganized seminiferous tubules induced by irradiation.

CONCLUSION

Our findings show for the first time that Maca has a protective effect on male reproductive damage induced by radiotherapy. Maca root reveals anti-apoptotic effect and protection against testicular damage via GRP78/CHOP/caspase-3 pathway.

Advances in the regulation of radiation-induced apoptosis by polysaccharides: A review

Polysaccharides are biomolecules composed of monosaccharides that are widely found in animals, plants and microorganisms and are of interest for their various health benefits. Cumulative studies have shown that the modulation of radiation-induced apoptosis by polysaccharides can be effective in preventing and treating a wide range of radiation injuries with safety and few side effects. Therefore, this paper summarizes the monosaccharide compositions, molecular weights, and structure-activity relationships of natural polysaccharides that regulate radiation-induced apoptosis, and also reviews the molecular mechanisms by which these polysaccharides modulate radiation-induced apoptosis, primarily focusing on promoting cancer cell apoptosis to enhance radiotherapy efficacy, reducing radiation damage to normal tissues, and inhibiting apoptosis in normal cells. Additionally, the role of gut microbiota in mediating the interaction between polysaccharides and radiation is discussed, providing innovative ideas for various radiation injuries, including hematopoiesis, immunity, and organ damage. This review will contribute to a better understanding of the value of natural polysaccharides in the field of radiation and provide guidance for the development of natural radioprotective agents and radiosensitizers.

Acupuncture for primary insomnia: Effectiveness, safety, mechanisms and recommendations for clinical practice

Primary insomnia (PI) is an increasing concern in modern society. Cognitive-behavioral therapy for insomnia is the first-line recommendation, yet limited availability and cost impede its widespread use. While hypnotics are frequently used, balancing their benefits against the risk of adverse events poses challenges. This review summarizes the clinical and preclinical evidence of acupuncture as a treatment for PI, discussing its potential mechanisms and role in reliving insomnia. Clinical trials show that acupuncture improves subjective sleep quality, fatigue, cognitive impairments, and emotional symptoms with minimal adverse events. It also positively impacts objective sleep processes, including prolonging total sleep time, improving sleep efficiency, reducing sleep onset latency and wake after sleep onset, and enhancing sleep architecture/structure, including increasing N3% and REM%, and decreasing N1%. However, methodological shortcomings in some trials diminish the overall quality of evidence. Animal studies suggest that acupuncture restores circadian rhythms in sleep-deprived rodents and improves their performance in behavioral tests, possibly mediated by various clinical variables and pathways. These may involve neurotransmitters, brain-derived neurotrophic factors, inflammatory cytokines, the hypothalamic-pituitary-adrenal axis, gut microbiota, and other cellular events. While the existing findings support acupuncture as a promising therapeutic strategy for PI, additional high-quality trials are required to validate its benefits.

Evaluation of the neuroprotective effect of quercetin against damage caused by gamma radiation

BACKGROUND AND OBJECTIVE

Radiation therapy is a routine clinical practice that has been used for a long time in the treatment of cancer patients. The most important dose-limiting organ in patients receiving radiotherapy for various conditions is the brain. The mechanisms underlying brain and pituitary gland damage caused by radiation are largely unknown. It is of great importance to use radioprotective agents to protect against damage. This study aims to evaluate the neuroprotective effects of quercetin in experimental radiation-induced brain and pituitary gland damage.

MATERIALS AND METHODS

A total of 60 adult male Wistar-albino rats were randomly divided into six groups (control, sham, radiation, quercetin, radiation + quercetin, and quercetin + radiation groups, with ten rats in each group). Quercetin was given to rats by oral gavage at 50 mg/kg/day. A whole-body single dose of 10 Gy radiation was applied to the rats. Tissue samples belonging to the groups were compared after excision. Histopathological changes in the brain tissue and pituitary gland were examined with hematoxylin-tissue samples in the groups and compared histologically and immunohistochemically.

RESULTS

The histopathological examination of the brain and anterior pituitary gland sections showed marked damage in the radiation-treated rats, while the quercetin-administered groups showed normal tissue architecture. While neuropeptid Y immunoreactivity was increased, synaptophysin immunoreactivity was decreased in the brains of radiation-treated rats. However, when neuropeptide Y and synaptophysin expression were assessed in the anterior pituitary gland, there was no significant difference between the groups.

CONCLUSION

Consequently, quercetin may be a potential pharmacological agent in modulating radiation-induced damage in rats. However, extra experimental and preclinical studies are needed to confirm our findings before they can be used clinically.

Quercetin alleviates cadmium-induced BRL-3A cell apoptosis by inhibiting oxidative stress and the PERK/IRE1α/ATF6 signaling pathway

Cadmium (Cd) is a highly toxic environmental pollutant. The liver is an important metabolic organ in the body and is susceptible to Cd toxicity attacks. Quercetin (Que) is a flavonoid compound with pharmacological activities of scavenging free radicals and antioxidant activity. Previous studies have shown that Que can alleviate Cd caused hepatocyte apoptosis in rats, but the specific mechanism remains unclear. To explore the specific mechanism, we established a model of Cd toxicity and Que rescue in BRL-3A cells and used 4-phenylbutyrate (4-PBA), an endoplasmic reticulum stress (ERS) inhibitor, as positive control. Set up a control group, Cd treatment group, Cd and Que co treatment group, Que treatment group, Cd and 4-PBA co treatment group, and 4-PBA treatment group. Cell Counting Kit-8 (CCK-8) method was employed to measure cell viability. Fluorescence staining was applied to observe cell apoptosis. Flow cytometry was performed to detect reactive oxygen species levels. Real-time quantitative polymerase chain reaction (qRT-PCR) and Western blot method was adopted to detect the mRNA and protein expression levels of ERS and apoptosis-related genes. The results showed that compared with the control group, the Cd treated group showed a significant decrease in cell viability (P < 0.01), an increase in intracellular ROS levels, and apoptosis. The mRNA and protein expression levels of ERS and apoptosis related factors such as GRP78, IRE1α, XBP1, ATF6, Caspase-12, Caspase-3 and Bax in the cells were significantly increased (P < 0.01), while the mRNA and protein expression levels of Bcl-2 were significantly reduced (P < 0.01). Compared with the Cd treatment group, the Cd and Que co treatment group and the Cd and 4-PBA co treatment group showed a significant increase in cell viability (P < 0.01), a decrease in intracellular ROS levels, a decrease in cell apoptosis, and a significant decrease in the expression levels of ERS and apoptosis related factors mRNA and protein (P < 0.01), as well as a significant increase in Bcl-2 mRNA and protein expression (P < 0.01). We confirmed that Que could alleviate the apoptosis caused by Cd in BRL-3A cells, and the effects of Que were similar to those of ERS inhibitor.

Fruits and their phytochemicals in mitigating the ill effects of ionizing radiation: review on the existing scientific evidence and way forward

Although helpful in treating cancer, exposure to ionizing radiation can sometimes cause severe side effects, negating its benefit. In addition to its use in clinics, a nontoxic radioprotective agent can also be beneficial in occupational settings where humans are occupationally exposed for prolonged periods to low doses of radiation. Scientific studies using laboratory animals have shown that the fruits Aegle marmelos, Capsicum annuum, Citrus aurantium, Citrullus lanatus, Crataegus microphylla, Eugenia jambolana, Emblica officinalis, Garcinia kola, Grewia asiatica, Hippophae rhamnoides, Malus baccata, Malpighia glabra or Malpighia emarginata, Mangifera indica, Prunus domestica, Prunus avium, Prunus armeniaca, Psoralea corylifolia, Punica granatum, Solanum lycopersicum, Terminalia chebula, Vaccinium macrocarpon, Vitis vinifera and Xylopia aethiopica, and the phytochemicals gallic acid, ellagic acid, quercetin, geraniin, corilagin, ascorbic acid, hesperetin, ursolic acid, lycopene, naringin, hesperidin, rutin, resveratrol, β-sitosterol, apigenin, luteolin, chlorogenic acid, caffeic acid, mangiferin, diosmin, ferulic acid, and kaempferol are effective in preventing radiation-induced ill effects. Clinical studies with Emblica officinalis and Punica granatum have also shown that fruits help mitigate radiation-induced mucositis, dermatitis, and cystitis. For the first time, the current review summarizes the beneficial effects of fruits and phytochemicals in mitigating radiation-induced damage, the underlying mechanisms and the existing lacunae for future studies to be undertaken for the benefit of humans and the nutraceutical and agri-based industries.

Targeting Estrogen Signaling in the Radiation-induced Neurodegeneration: A Possible Role of Phytoestrogens

Radiation for medical use is a well-established therapeutic method with an excellent prognosis rate for various cancer treatments. Unfortunately, a high dose of radiation therapy comes with its own share of side effects, causing radiation-induced non-specific cellular toxicity; consequently, a large percentage of treated patients suffer from chronic effects during the treatment and even after the post-treatment. Accumulating data evidenced that radiation exposure to the brain can alter the diverse cognitive-related signaling and cause progressive neurodegeneration in patients because of elevated oxidative stress, neuroinflammation, and loss of neurogenesis. Epidemiological studies suggested the beneficial effect of hormonal therapy using estrogen in slowing down the progression of various neuropathologies. Despite its primary function as a sex hormone, estrogen is also renowned for its neuroprotective activity and could manage radiation-induced side effects as it regulates many hallmarks of neurodegenerations. Thus, treatment with estrogen and estrogen-like molecules or modulators, including phytoestrogens, might be a potential approach capable of neuroprotection in radiation-induced brain degeneration. This review summarized the molecular mechanisms of radiation effects and estrogen signaling in the manifestation of neurodegeneration and highlighted the current evidence on the phytoestrogen mediated protective effect against radiationinduced brain injury. This existing knowledge points towards a new area to expand to identify the possible alternative therapy that can be taken with radiation therapy as adjuvants to improve patients' quality of life with compromised cognitive function.

Pathogenic mechanisms and therapeutic promise of phytochemicals and nanocarriers based drug delivery against radiotherapy-induced neurotoxic manifestations

Radiotherapy is one of the extensively used therapeutic modalities in glioblastoma and other types of cancers. Radiotherapy is either used as a first-line approach or combined with pharmacotherapy or surgery to manage and treat cancer. Although the use of radiotherapy significantly increased the survival time of patients, but its use has been reported with marked neuroinflammation and cognitive dysfunction that eventually reduced the quality of life of patients. Based on the preclinical and clinical investigations, the profound role of increased oxidative stress, nuclear translocation of NF-kB, production of proinflammatory cytokines such as TNF-α, IL-6, IL-β, increased level of MMPs, increased apoptosis, reduced angiogenesis, neurogenesis, and histological aberrations in CA1, CA2, CA3 and DG region of the hippocampus have been reported. Various pharmacotherapeutic drugs are being used as an adjuvant to counteract this neurotoxic manifestation. Still, most of these drugs suffer from systemic adverse effect, causes interference to ongoing chemotherapy, and exhibit pharmacokinetic limitations in crossing the blood-brain barrier. Therefore, various phytoconstituents, their nano carrier-based drug delivery systems and miRNAs have been explored to overcome the aforementioned limitations. The present review is focused on the mechanism and evidence of radiotherapy-induced neuroinflammation and cognitive dysfunction, pathological and molecular changes in the brain homeostasis, available adjuvants, their limitations. Additionally, the potential role and mechanism of neuroprotection of various nanocarrier based natural products and miRNAs have been discussed.

Phytochemicals Targeting Oxidative Stress, Interconnected Neuroinflammatory, and Neuroapoptotic Pathways Following Radiation

The radiation for therapeutic purposes has shown positive effects in different contexts; however, it can increase the risk of many age-related and neurodegenerative diseases such as Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), Huntington's disease (HD), and Parkinson's disease (PD). These different outcomes highlight a dose-response phenomenon called hormesis. Prevailing studies indicate that high doses of radiation could play several destructive roles in triggering oxidative stress, neuroapoptosis, and neuroinflammation in neurodegeneration. However, there is a lack of effective treatments in combating radiation-induced neurodegeneration, and the present drugs suffer from some drawbacks, including side effects and drug resistance. Among natural entities, polyphenols are suggested as multi-target agents affecting the dysregulated pathogenic mechanisms in neurodegenerative disease. This review discusses the destructive effects of radiation on the induction of neurodegenerative diseases by dysregulating oxidative stress, apoptosis, and inflammation. We also describe the promising effects of polyphenols and other candidate phytochemicals in preventing and treating radiation-induced neurodegenerative disorders, aiming to find novel/potential therapeutic compounds against such disorders.

Quercetin Prevents Radiation-Induced Oral Mucositis by Upregulating BMI-1

Radiation-induced oral mucositis is a major adverse event of radiotherapy. Severe oral mucositis may cause unwanted interruption in radiotherapy and reduce long-term survival in cancer patients receiving radiotherapy, but until now, there have been no effective options for preventing radiation-induced oral mucositis. Quercetin is a flavonoid that is widely found in food species and has anti-inflammatory, antioxidant, and anticancer activities. In this study, we investigated a new role of quercetin in preventing radiation-induced oral mucositis. Quercetin exerted preventive effects against radiation-induced oral mucositis induced by single-dose (25 Gy) ionizing radiation or fractionated ionizing radiation (8 Gy × 3) in C57BL/6 mice and maintained the proliferation ability of basal epithelial cells. Quercetin pretreatment alleviated reactive oxygen species generation, NF-κB pathway activation, and downstream proinflammatory cytokine production and reduced DNA double-strand breaks and cellular senescence induced by ionizing radiation. Quercetin also upregulated BMI-1 expression in oral epithelial cells and promoted ulcer repair. In addition, quercetin exerted similar radioprotective effects in irradiated primary cultured normal human keratinocytes, reduced reactive oxygen species generation and proinflammatory cytokine release, and promoted DNA double-strand break repair and wound healing by upregulating the expression of BMI-1, which is a polycomb group protein. Thus, quercetin can block multiple pathological processes of radiation-induced oral mucositis by targeting BMI-1 and may be a potential treatment option for preventing radiation-induced oral mucositis.

Quercetin and its role in modulating endoplasmic reticulum stress: A review

The endoplasmic reticulum (ER) is the place where proteins and lipids are biosynthesized and where transmembrane proteins are folded. Both pathological and physiological situations may disturb the function of the ER, resulting in ER stress. Under stress conditions, the cells initiate a defensive procedure known as the unfolded protein response (UPR). Cases of severe stress lead to autophagy and/or the induction of cell apoptosis. Many studies implicate ER stress as a major factor contributing to many diseases. Therefore, the modulation of ER stress pathways has become an attractive therapeutic target. Quercetin is a plant-derived metabolite belonging to the flavonoids class which presents a range of beneficial effects including anti-inflammatory, cardioprotective, anti-oxidant, anti-obesity, anti-carcinogenic, anti-atherosclerotic, anti-diabetic, anti-hypercholesterolemic, and anti-apoptotic activities. Quercetin also has anti-cancer activity, and can be used as an adjuvant to decrease resistance to cancer chemotherapy. Furthermore, the effect of quercetin can be increased with the help of nanotechnology. This review discusses the role of quercetin in the modulation of ER stress (and related diseases) and provides novel evidence for the beneficial use of quercetin in therapy.

Quercetin: A Bioactive Compound Imparting Cardiovascular and Neuroprotective Benefits: Scope for Exploring Fresh Produce, Their Wastes, and By-Products

Quercetin, a bioactive secondary metabolite, holds incredible importance in terms of bioactivities, which has been proved by in vivo and in vitro studies. The treatment of cardiovascular and neurological diseases by quercetin has been extensively investigated over the past decade. Quercetin is present naturally in appreciable amounts in fresh produce (fruits and vegetables). However, today, corresponding to the growing population and global demand for fresh fruits and vegetables, a paradigm shift and focus is laid towards exploring industrial food wastes and/or byproducts as a new resource to obtain bioactive compounds such as quercetin. Based on the available research reports over the last decade, quercetin has been suggested as a reliable therapeutic candidate for either treating or alleviating health issues, mainly those of cardiovascular and neurological diseases. In the present review, we have summarized some of the critical findings and hypotheses of quercetin from the available databases foreseeing its future use as a potential therapeutic agent to treat cardiovascular and neurological diseases. It is anticipated that this review will be a potential reference material for future research activities to be undertaken on quercetin obtained from fresh produce as well as their respective processing wastes/byproducts that rely on the circular concept.

Cholinesterase Inhibitory Potential of Quercetin towards Alzheimer's Disease - A Promising Natural Molecule or Fashion of the Day? - A Narrowed Review

Natural substances are known to have strong protective effects against neurodegenerative diseases. Among them, phenolic compounds, especially flavonoids, come to the fore with their neuroprotective effects. Since quercetin, which is found in many medicinal plants and foods, is also taken through diet, its physiological effects on humans are imperative. Many studies have been published up to date on the neuroprotective properties of quercetin, a flavanol derivative. However, there is no review published so far summarizing the effect of quercetin on the cholinesterase (ChE) enzymes related to the cholinergic hypothesis, which is one of the pathological mechanisms of Alzheimer's Disease (AD). However, ChE inhibitors, regardless of natural or synthetic, play a vital role in the treatment of AD. Although the number of studies on the ChE inhibitory effect of quercetin is limited, it deserves to be discussed in a review article. With this sensitivity, the neuroprotective effect of quercetin against AD through ChE inhibition was scrutinized in the current review study. In addition, studies on the bioavailability of quercetin and its capacity to cross the blood-brain barrier and how this capacity and bioavailability can be increased were given. Generally, studies containing data published in recent years were obtained from search engines such as PubMed, Scopus, and Medline and included herein. Consequently, quercetin should not be considered as a fashionable natural compound and should be identified as a promising compound, especially with increased bioavailability, for the treatment of AD.

Radioprotective Effect of Flavonoids on Ionizing Radiation-Induced Brain Damage

Patients receiving brain radiotherapy may suffer acute or chronic side effects. Ionizing radiation induces the production of intracellular reactive oxygen species and pro-inflammatory cytokines in the central nervous system, leading to brain damage. Complementary Chinese herbal medicine therapy may reduce radiotherapy-induced side effects. Flavonoids are a class of natural products which can be extracted from Chinese herbal medicine and have been shown to have neuroprotective and radioprotective properties. Flavonoids are effective antioxidants and can also inhibit regulatory enzymes or transcription factors important for controlling inflammatory mediators, affect oxidative stress through interaction with DNA and enhance genomic stability. In this paper, radiation-induced brain damage and the relevant molecular mechanism were summarized. The radio-neuro-protective effect of flavonoids, i.e., antioxidant, anti-inflammatory and maintaining genomic stability, were then reviewed. We concluded that flavonoids treatment may be a promising complementary therapy to prevent radiotherapy-induced brain pathophysiological changes and cognitive impairment.

The novel ALK inhibitor ZX-29 induces apoptosis through inhibiting ALK and inducing ROS-mediated endoplasmic reticulum stress in Karpas299 cells

It is a well-known fact that 60%-85% of anaplastic large cell lymphoma (ALCL) is mainly driven by the anaplastic lymphoma kinase (ALK) fusion protein. Although ALK-positive ALCL patients respond significantly to ALK inhibitors, the development of resistance is inevitable, which requires the development of new therapeutic strategies for ALK-positive ALCL. Here, we investigated the anticancer activities of N-(2((5-chloro-2-((2-methoxy-6-(4-methylpiperazin-1-yl)pyridin-3yl)amino)pyrimidin-4-yl)amino)phenyl)methanesulfonamide (ZX-29), a newly synthesized ALK inhibitor, against nucleophosmin-ALK-positive cell line Karpas299. We demonstrated that ZX-29 decreased Karpas299 cells growth and had better cytotoxicity than ceritinib, which was mediated through downregulating the expression of ALK and related proteins, inducing cell cycle arrest, and promoting cell apoptosis. Moreover, ZX-29-induced cell apoptosis by inducing endoplasmic reticulum stress (ERS). In addition, ZX-29 increased the generation of reactive oxygen species (ROS), and cells pretreatment with N-acetyl- l-cysteine could attenuate ZX-29-induced cell apoptosis and ERS. Taken together, ZX-29 inhibited Karpas299 cell proliferation and induced apoptosis through inhibiting ALK and its downstream protein expression and inducing ROS-mediated ERS. Therefore, our results provide evidence for a novel antitumor candidate for the further investigation.

Neuroprotective Role of Quercetin on Rotenone-Induced Toxicity in SH-SY5Y Cell Line Through Modulation of Apoptotic and Autophagic Pathways

The detrimental impact on the food chain due to the overuse of rotenone is partly responsible for alpha-synuclein (α-syn) mediated neurotoxicity. It is hypothesized that rotenone overdose leads to cytosolic proteopathy resulting in modulation of apoptosis and autophagic pathways. The aim of our study is to explore the neuroprotective role of quercetin, a beneficial polyphenol against rotenone-induced neurotoxicity in dopaminergic human SH-SY5Y cell lines. In our study we demonstrated the correlation of rotenone-induced neurotoxicity through elevation of intracellular reactive oxygen species (ROS) and imbalance in the mitochondrial membrane potential (MMP). Moreover, the morphological distortion of cell, condensation of nuclei, externalization of the inner phosphatidylserine, cleavage of caspase 3, and Poly ADP Ribose Polymerase (PARP) confirmed apoptosis. However, all these lethal effects were ameliorated by treatment of quercetin to the cells. On the other hand rotenone has a strong effect on autophagy which is a regulated degrading and recycling cellular process to remove dysfunctional proteins. Indeed, rotenone-mediated autophagy resulted in the enhancement of autophagosome-bound microtubule-associated protein light chain-3 (LC3-II) expression. Furthermore, excess accumulation of acidic vesicles was detected in presence of rotenone. Lysosome associated membrane protein (LAMP-2A) is yet another crucial protein that recruits overexpressed or misfolded proteins into the lumen of lysosome to trigger autophagy. In all cases the impact of rotenone on the cells acquired significant protection through quercetin treatment. In the present work we therefore opine the prospects of quercetin as a therapeutic candidate against neurotoxicity.