Mitochondrial dysfunction in psychiatric and neurological diseases: cause(s), consequence(s), and implications of antioxidant therapy

Curcumin protects against aging-related stress and dysfunction through autophagy activation in rat brain

BACKGROUND

Curcumin (Curcuma longa) is a well-known medicinal plant that induces autophagy in various model species, helping maintain cellular homeostasis. Its role as a caloric restriction mimetic (CRM) is being investigated. This study explores the potential of curcumin (CUR), as a CRM, to provide neuroprotection in D galactose induced accelerated senescence model of rats through modulation of autophagy. For six weeks, male rats received simultaneous supplementation of D-gal (300 mg/kg b.w., subcutaneously) and CUR (200 mg/kg b.w., oral).

METHOD AND RESULTS

The oxidative stress indices, antioxidants, and electron transport chain complexes in brain tissues were measured using standard methods. Reverse transcriptase-polymerase chain reaction (RT-PCR) gene expression analysis was used to evaluate the expression of autophagy, neuroprotection, and aging marker genes. Our results show that curcumin significantly (p ≤ 0.05) enhanced the level of antioxidants and considerably lowered the level of oxidative stress markers. Supplementing with CUR also increased the activity of electron transport chain complexes in the mitochondria of aged brain tissue, demonstrating the antioxidant potential of CUR at the mitochondrial level. CUR was found to upregulate the expression of the aging marker gene (SIRT-1) and the genes associated with autophagy (Beclin-1 and ULK-1), as well as neuroprotection (NSE) in the brain. The expression of IL-6 and TNF-α was downregulated.

CONCLUSION

Our findings demonstrate that CUR suppresses oxidative damage brought on by aging by modulating autophagy. These findings imply that curcumin might be beneficial for neuroprotection in aging and age-related disorders.

Exploring hub genes and crucial pathways linked to oxidative stress in bipolar disorder depressive episodes through bioinformatics analysis

Background

Bipolar disorder (BD) is a complex and serious psychiatric condition primarily characterized by bipolar depression, with the underlying genetic determinants yet to be elucidated. There is a substantial body of literature linking psychiatric disorders, including BD, to oxidative stress (OS). Consequently, this study aims to assess the relationship between BD and OS by identifying key hub genes implicated in OS pathways.

Methods

We acquired gene microarray data from GSE5392 through the Gene Expression Omnibus (GEO). Our approach encompassed differential expression analysis, weighted gene co-expression network analysis (WGCNA), and Protein-Protein Interaction (PPI) Network analysis to pinpoint hub genes associated with BD. Subsequently, we utilized Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Set Enrichment Analysis (GSEA) to identify hub genes relevant to OS. To evaluate the diagnostic accuracy of these hub genes, we performed receiver operating characteristic curve (ROC) analysis on both GSE5388 and GSE5389 datasets. Furthermore, we conducted a study involving ten BD patients and ten healthy controls (HCs) who met the special criteria, assessing the expression levels of these hub genes in their peripheral blood mononuclear cells (PBMCs).

Results

We identified 411 down-regulated genes and 69 up-regulated genes for further scrutiny. Through WGCNA, we obtained 22 co-expression modules, with the sienna3 module displaying the strongest association with BD. By integrating differential analysis with genes linked to OS, we identified 44 common genes. Subsequent PPI Network and WGCNA analyses confirmed three hub genes as potential biomarkers for BD. Functional enrichment pathway analysis revealed their involvement in neuronal signal transduction, oxidative phosphorylation, and metabolic obstacle pathways. Using the Cytoscape plugin "ClueGo assay," we determined that a majority of these targets regulate neuronal synaptic plasticity. ROC curve analysis underscored the excellent diagnostic value of these three hub genes. Quantitative reverse transcription-PCR (RT-qPCR) results indicated significant changes in the expression of these hub genes in the PBMCs of BD patients compared to HCs.

Conclusion

We identified three hub genes (TAC1, MAP2K1, and MAP2K4) in BD associated with OS, potentially influencing the diagnosis and treatment of BD. Based on the GEO database, our study provides novel insights into the relationship between BD and OS, offering promising therapeutic targets.

Use of 31 P magnetisation transfer magnetic resonance spectroscopy to measure ATP changes after 670 nm transcranial photobiomodulation in older adults

Mitochondrial function declines with age, and many pathological processes in neurodegenerative diseases stem from this dysfunction when mitochondria fail to produce the necessary energy required. Photobiomodulation (PBM), long-wavelength light therapy, has been shown to rescue mitochondrial function in animal models and improve human health, but clinical uptake is limited due to uncertainty around efficacy and the mechanisms responsible. Using 31 P magnetisation transfer magnetic resonance spectroscopy (MT-MRS) we quantify, for the first time, the effects of 670 nm PBM treatment on healthy ageing human brains. We find a significant increase in the rate of ATP synthase flux in the brain after PBM in a cohort of older adults. Our study provides initial evidence of PBM therapeutic efficacy for improving mitochondrial function and restoring ATP flux with age, but recognises that wider studies are now required to confirm any resultant cognitive benefits.

Antioxidant Therapy Reduces Oxidative Stress, Restores Na,K-ATPase Function and Induces Neuroprotection in Rodent Models of Seizure and Epilepsy: A Systematic Review and Meta-Analysis

Epilepsy is a neurological disorder characterized by epileptic seizures resulting from neuronal hyperexcitability, which may be related to failures in Na,K-ATPase activity and oxidative stress participation. We conducted this study to investigate the impact of antioxidant therapy on oxidative stress, Na,K-ATPase activity, seizure factors, and mortality in rodent seizure/epilepsy models induced by pentylenetetrazol (PTZ), pilocarpine (PILO), and kainic acid (KA). After screening 561 records in the MEDLINE, EMBASE, Web of Science, Science Direct, and Scopus databases, 22 were included in the systematic review following the PRISMA guidelines. The meta-analysis included 14 studies and showed that in epileptic animals there was an increase in the oxidizing agents nitric oxide (NO) and malondialdehyde (MDA), with a reduction in endogenous antioxidants reduced glutathione (GSH) and superoxide dismutase (SO). The Na,K-ATPase activity was reduced in all areas evaluated. Antioxidant therapy reversed all of these parameters altered by seizure or epilepsy induction. In addition, there was a percentage decrease in the number of seizures and mortality, and a meta-analysis showed a longer seizure latency in animals using antioxidant therapy. Thus, this study suggests that the use of antioxidants promotes neuroprotective effects and mitigates the effects of epilepsy. The protocol was registered in the Prospective Register of Systematic Reviews (PROSPERO) CRD42022356960.

Generation of Highly Antioxidant Submicron Particles from Myrtus communis Leaf Extract by Supercritical Antisolvent Extraction Process

Submicron particles have been produced from an ethanolic extract of Myrtus communnis leaves using supercritical carbon dioxide technology, hereinafter referred to as Supercritical Antisolvent Extraction (SAE). The influence of pressure (9-20 MPa), temperature (308 and 328 K) and injection rate (3 and 8 mL/min) on the particles' precipitation has been investigated, and it has been confirmed that increases in pressure and temperature led to smaller particle sizes. The obtained particles had a quasi-spherical shape with sizes ranging from 0.42 to 1.32 μm. Moreover, the bioactivity of the generated particles was assessed and large contents of phenolic compounds with a high antioxidant activity were measured. The particles were also subjected to in vitro studies against oxidative stress. The myrtle particles demonstrated cytoprotective properties when applied at low concentrations (1 μM) to macrophage cell lines.

The Credible Role of Curcumin in Oxidative Stress-Mediated Mitochondrial Dysfunction in Mammals

Oxidative stress and mitochondrial dysfunction are associated with the pathogenesis of several human diseases. The excessive generation of reactive oxygen species (ROS) and/or lack of adequate antioxidant defenses causes DNA mutations in mitochondria, damages the mitochondrial respiratory chain, and alters membrane permeability and mitochondrial defense mechanisms. All these alterations are linked to the development of numerous diseases. Curcumin, an active ingredient of turmeric plant rhizomes, exhibits numerous biological activities (i.e., antioxidant, anti-inflammatory, anticancer, and antimicrobial). In recent years, many researchers have shown evidence that curcumin has the ability to reduce the oxidative stress- and mitochondrial dysfunction-associated diseases. In this review, we discuss curcumin’s antioxidant mechanism and significance in oxidative stress reduction and suppression of mitochondrial dysfunction in mammals. We also discuss the research gaps and give our opinion on how curcumin research in mammals should proceed moving forward.

The Neuroprotective Effect of Increased PINK1 Expression Following Glutamate Excitotoxicity in Neuronal Cells

Ischemic injury in patients with stroke often leads to neuronal damage and mitochondrial dysfunction. Neuronal injury caused by ischemia can be partly attributed to glutamate (L-Glu) excitotoxicity. Previous studies have shown that PTEN-induced kinase 1 (PINK1) plays a neuroprotective role in ischemic brain injury by regulating mitochondrial integrity and function. However, there are few reports on the expression of PINK1 in L-Glu excitotoxicity models, its effect on neuronal survival, and whether PINK1 plays a protective role in stroke by regulating mitophagy. In the present study, different concentrations of L-Glu inhibited the viability of neurons. After L-Glu treatment at different times, the mRNA level, protein level, and cellular fluorescence intensity of PINK1 first increased and then decreased. Compared with normal cells, cells with low PINK1 expression enhanced the inhibitory effect of L-Glu on neuronal activity, while those with high PINK1 expression showed a protective effect on neurons by alleviating mitochondrial membrane potential loss. In addition, RAP (an autophagy activator) could increase the co-localization of the mitophagy-related proteins light chain 3 (LC3) and Tom20, whereas 3-MA (an autophagy inhibitor) exerted the opposite effect. Finally, we found that L-Glu could induce the expression of PINK1/Parkin/ LC3 in neurons at both mRNA and protein levels, while RAP could further increase their expression, and 3-MA decreased their expression. Taken together, PINK1 protects against L-Glu-induced neuronal injury by protecting mitochondrial function, and the potential protective mechanism may be closely related to the enhancement of mitophagy mediated by the PINK1/Parkin signaling pathway.

Antithrombogenic properties of Tulbaghia violacea aqueous leaf extracts: assessment of platelet activation and whole blood clotting kinetics

Tulbaghia violacea plant extracts have been investigated for their potential therapeutic effects in the management of various ailments, among which are cardiovascular diseases, due to the wide range of phytocompounds that the plant possesses. One of the major challenges in clinical practice is the inability to control platelet activation and clotting caused by cardiovascular disease interventions. Current treatment methods to inhibit platelet aggregation and thromboxane formation have been associated with major undesirable side effects. This has led to increased research studies on the development of newer and more effective antiplatelet agents. In particular, there has been a growing interest on the potential antiplatelet activity of plant-derived extracts. Hence this study methodically evaluates the anticlotting and antiplatelet properties of T. violacea aqueous leaf extracts. The platelet activity of the plant extracts was assessed using total platelet adhesion, platelet morphology and whole blood clotting kinetics. The 0.1 mg ml-1 T. violacea extract mixed with blood plasma demonstrated the lowest platelet adhesion and activation and also reduced whole blood clotting kinetics. There was a reduction of about 70% in platelet adhesion for the 0.1 mg ml-1 treatment compared to the control in the first 15 min which was supported by morphological characterization under SEM. These observations suggest that T. violacea may be a potential antiplatelet therapeutic agent to inhibit the initial step of platelet adhesion and ultimately reduce the incidence of cardiovascular events.

AIF3 splicing switch triggers neurodegeneration

BACKGROUND

Apoptosis-inducing factor (AIF), as a mitochondrial flavoprotein, plays a fundamental role in mitochondrial bioenergetics that is critical for cell survival and also mediates caspase-independent cell death once it is released from mitochondria and translocated to the nucleus under ischemic stroke or neurodegenerative diseases. Although alternative splicing regulation of AIF has been implicated, it remains unknown which AIF splicing isoform will be induced under pathological conditions and how it impacts mitochondrial functions and neurodegeneration in adult brain.

METHODS

AIF splicing induction in brain was determined by multiple approaches including 5' RACE, Sanger sequencing, splicing-specific PCR assay and bottom-up proteomic analysis. The role of AIF splicing in mitochondria and neurodegeneration was determined by its biochemical properties, cell death analysis, morphological and functional alterations and animal behavior. Three animal models, including loss-of-function harlequin model, gain-of-function AIF3 knockin model and conditional inducible AIF splicing model established using either Cre-loxp recombination or CRISPR/Cas9 techniques, were applied to explore underlying mechanisms of AIF splicing-induced neurodegeneration.

RESULTS

We identified a nature splicing AIF isoform lacking exons 2 and 3 named as AIF3. AIF3 was undetectable under physiological conditions but its expression was increased in mouse and human postmortem brain after stroke. AIF3 splicing in mouse brain caused enlarged ventricles and severe neurodegeneration in the forebrain regions. These AIF3 splicing mice died 2-4 months after birth. AIF3 splicing-triggered neurodegeneration involves both mitochondrial dysfunction and AIF3 nuclear translocation. We showed that AIF3 inhibited NADH oxidase activity, ATP production, oxygen consumption, and mitochondrial biogenesis. In addition, expression of AIF3 significantly increased chromatin condensation and nuclear shrinkage leading to neuronal cell death. However, loss-of-AIF alone in harlequin or gain-of-AIF3 alone in AIF3 knockin mice did not cause robust neurodegeneration as that observed in AIF3 splicing mice.

CONCLUSIONS

We identified AIF3 as a disease-inducible isoform and established AIF3 splicing mouse model. The molecular mechanism underlying AIF3 splicing-induced neurodegeneration involves mitochondrial dysfunction and AIF3 nuclear translocation resulting from the synergistic effect of loss-of-AIF and gain-of-AIF3. Our study provides a valuable tool to understand the role of AIF3 splicing in brain and a potential therapeutic target to prevent/delay the progress of neurodegenerative diseases.

Biochemical Profiling for Antioxidant and Therapeutic Potential of Pakistani Chickpea (Cicer arietinum L.) Genetic Resource

In Pakistan, chickpeas (Cicer arietinum L.) are the largest grown legume crops, especially in desert areas. Along with an excellent source of nutrition, chickpea seeds have discernible medicinal and antioxidant characteristics. The diverse set of 90 chickpea genotypes (66 desi and 24 kabuli) were collected from different research zones in Pakistan, and seed flour was used for biochemical profiling. Genotypes were significantly different (Tukey HSD test, P < 0.05) for the traits under investigation. In non-enzymatic antioxidants, highest seed total phenolic contents (TPC) (34725 ± 275 μM/g s. wt.) was found in CM-98 (desi), ascorbic acid (AsA) (69.23 ± 2.25 μg/g s. wt.) in WH-3 (desi), and total flavonoid content (TFC) (394.98 ± 13.06 μg/mL sample) was detected in WH-11 (desi). In the class of enzymatic antioxidants, the highest seed ascorbate peroxidase (APX) (1680 ± 40 Units/g s. wt.) was detected in Tamman-2013 (kabuli), peroxidases (POD) (2564.10 ± 233.10 Units/g s. wt.) activity in CM1235/08 (desi), and superoxide dismutase (SOD) (279.76 ± 50 Units/g s. wt.) was detected in CH24/11 (desi). Highest seed catalase activity (CAT) (893 ± 50 Units/g s. wt.) and proline content (272.50 ± 20.82 μg/g s. wt.) was detected in an ICC-4951 (desi). In hydrolytic enzymes, the highest activity of esterase (37.05 μM/min/g s. wt) was found in, CH56/09(Kabuli), protease (11080 ± 10 Units/g s. wt.) in Karak-2 (desi), and α-amylase (213.02 ± 3.20 mg/g s. wt.) was observed in CH74/08 (kabuli). In other biochemical parameters, the highest seed total oxidant status (TOS) (356 ± 17.50 μM/g s. wt.) was detected in CM3457/91 (desi); malondialdehyde (MDA) content (295.74 ± 3.097 uM/g s. wt.) was observed in CM-2008 (kabuli), and total antioxidant capacity (TAC) (8.36 ± 0.082 μM/g s. wt.) was found in CM-72 (desi). In case of pigment analysis, Sheenghar-2000 (desi) depicted highest lycopene (12.579 ± 0.313 μg/g s. wt.) and total carotenoids (58.430.23 ± 0.569 μg/g s. wt.) contents. For seed therapeutic potential, the highest seed α-amylase inhibition (82.33 ± 8.06%) was observed in CM-88 (desi), while WH-1, WH-6, and ICCV-96030 (desi) depicted the highest value for seed anti-inflammatory potential (78.88 ± 0.55%). Genotypes with the highest antioxidant and therapeutic potential can be utilized as a natural antioxidant source and in breeding programs aimed at improving these traits in new breeding lines.

Effect of soil amendments on antioxidant activity and photosynthetic pigments in pea crops grown in arsenic contaminated soil

The mechanism of arsenic (As) immobilization in soils is crucial for improving photosynthetic pigments and antioxidants in food crops. The effects of soil amendments with arbuscular mycorrhizal fungi (AMF), biochar (BC), selenium (Se), sulfur (S) and Si-gel on the concentrations of chlorophyll, carotenoid, proline, malondialdehyde (MDA), and the activity of ascorbate peroxidase (APX), guaiacol peroxidase (POD), and catalase (CAT) were studied in BARI pea (Pisum sativum) under As stress. Soil amendments with AMF, Se, Si-gel and S enhanced chlorophyll a and total chlorophyll contents by 31–35% and 60–75%, respectively. Likewise, CAT activity was increased by 24–46% in BC, AMF, Se, Si-gel and S-treated pea, respectively. APX and POD activity was also found to be enriched with the treatment of BC, AMF and Se. In contrast, the content of MDA and proline was found lower than that of control in peas. These findings indicate that oxidative damage, osmotic stress and cell injury were possibly reduced in As-stressed peas. Particularly, AMF and Se both were comparatively more potential in comparison to BC. Thus, soil amendments with AMF, BC and Se are significantly important for improving antioxidant enzyme activity of food crops grown in soil with elevated As levels.

Spermidine, a caloric restriction mimetic, provides neuroprotection against normal and D-galactose-induced oxidative stress and apoptosis through activation of autophagy in male rats during aging

Spermidine (SPD) is a natural polyamine present in all living organisms and is involved in the maintenance of cellular homeostasis by inducing autophagy in different model organisms. Its role as a caloric restriction mimetic (CRM) is still being investigated. We have undertaken this study to investigate whether SPD, acting as a CRM, can confer neuroprotection in D-galactose induced accelerated senescence model rat and naturally aged rats through modulation of autophagy and inflammation. Young male rats (4 months), D-gal induced (500 mg/kg b.w., subcutaneously) aging and naturally aged (22 months) male rats were supplemented with SPD (10 mg/kg b.w., orally) for 6 weeks. Standard protocols were employed to measure prooxidants, antioxidants, apoptotic cell death and electron transport chain complexes in brain tissues. Gene expression analysis with reverse transcriptase-polymerase chain reaction (RT-PCR) was performed to assess the expression of autophagy and inflammatory marker genes. Our data demonstrate that SPD significantly (p ≤ 0.05) decreased the level of pro-oxidants and increased the level of antioxidants. SPD supplementation also augmented the activities of electron transport chain complexes in aged brain mitochondria thus proving its antioxidant potential at the level of mitochondria. RT-PCR data revealed that SPD up-regulated the expression of autophagy genes (ATG-3, Beclin-1, ULK-1 and LC3B) and down-regulated the expression of the inflammatory gene (IL-6) in aging brain. Our results provide first line of evidence that SPD provides neuroprotection against aging-induced oxidative stress by regulating autophagy, antioxidants level and also reduces neuroinflammation. These results suggest that SPD may be beneficial for neuroprotection during aging and age-related disorders.

Nutraceutical perspectives and value addition of phalsa (Grewia asiatica L.): A review

Phalsa (Grewia asiatica L.) is a food plant originating from Southeast Asia, and is cultivated primarily for its fruit. Phalsa fruit is consumed raw or used as a drink or food additive. Additionally, in vitro and in vivo studies have found that extracts from various parts of phalsa plants (especially the fruit) possess strong antioxidant, radioprotective, antimicrobial, antidiabetic, anti-inflammatory, anticancer, and cardio-protective properties. However, despite the identification of numerous nutritional and health benefits of phalsa, research into nutraceutical applications of the plant are somewhat limited. Therefore, the objective of this review was to explore the pharmacological, nutritional, phytochemical, and other potential uses of the phalsa plant. Recommendations for food scientists, nutritionists, and members of other allied disciplines are provided to help direct future research into the production, value addition, preservation, and phytochemical characterization of phalsa. Moreover, its potential health benefits are highlighted, along with the underlying mechanisms of action. PRACTICAL APPLICATIONS: The aim of the present review is to explore functional aspects of phalsa (Grewia asiatica L.) bioactive compounds, their role in improving health, as well as their possible application as a functional food ingredient.

Can mild cognitive impairment be stabilized by showering brain mitochondria with laser photons?

There is now substantial evidence that cerebral blood flow (CBF) declines with age. From age 20 to 60, CBF is estimated to dip about 16% and continues to drop at a rate of 0.4%/year. This CBF dip will slowly reduce oxygen/glucose delivery to brain thus lowering ATP energy production needed by brain cells to perform normal activities. Reduced ATP production from mitochondrial loss or damage in the wear-and-tear of aging worsens when vascular risk factors (VRF) to Alzheimer's disease develop that can accelerate both age-decline CBF and mitochondrial deficiency to a level where mild cognitive impairment (MCI) develops. To date, no pharmacological or any other treatment has been successful in reversing, stabilizing or delaying MCI. For the first time in medical interventions, a non-pharmacological, non-invasive, well-tolerated, easy to perform, free of significant side effects and cost-effective treatment may achieve what virtually all AD treatments in the past have been unable to accomplish. This intervention uses transcranial infrared brain stimulation (TIBS), a form of photobiomodulation (PBM). PBM is a bioenergetic non-ionizing, therapeutic approach using low level light emission from laser or light emitting diodes. PBM has been used in a number of neurological conditions including Parkinson's disease, depression, traumatic brain injury, and stroke with diverse reported benefits. This brief review examines the impact of reduced energy supply stemming from chronic brain hypoperfusion in the aging brain. In this context, the use of TIBS is planned in a randomized, placebo-controlled study of MCI patients to be done at our University Clinic. This article is part of the special issue entitled 'The Quest for Disease-Modifying Therapies for Neurodegenerative Disorders'.

[Organic and psychiatric intricacy: The complex psychiatric disorder concept, paraclinical investigations]

The purpose of this article is to describe complex psychiatric disorders, to recall "minimal classical" explorations in psychiatry, to describe the concept of "complex psychiatric disorders" and to propose a systematized method of exploration. Some organic diseases are well known for their links with psychiatric disorders (manic syndrome and hyperthyroidism, depressive syndrome and corticotropic insufficiency, anxiety disorder and heart disease, etc.). Many other neurological, autoimmune, metabolic, paraneoplastic or endocrine pathologies can have essentially psycho-behavioral manifestations before being neurological or systemic. A large number of factors (nutritional, toxic, immunological, etc.), often ignored, influence the links between organicity and psychiatric pathologies. It is necessary to optimize the medical management of these patients in whom the psychiatric diagnosis masks a curable organo-psychiatric cause.

Active Components, Antioxidant, Inhibition on Metabolic Syndrome Related Enzymes, and Monthly Variations in Mature Leaf Hawk Tea

Hawk tea is a rich and edible resource, traditionally used as a beverage in South China. This drink has many pharmacologic effects, such as acting as an antioxidant and reducing blood sugar and lipids. The objective of this work was to explore the active compound contents, bioactivities and their monthly changes, and optimize the harvest time. In the present study, Hawk tea from each month in 2017 was collected and extracted with 70% (v/v) ethanol. The contents of the total flavonoids and total phenols were determined using the colorimetric method. We determined the contents of seven characteristic active substances—hyperin, isoquercitrin, trifolin, quercitrin, astragalin, quercetin, and kaempferol—using high-performance liquid chromatography. The crude extract was tested for its antioxidant and inhibitory properties on enzymes involved in metabolic syndrome. Specifically, 2,2-diphenyl-1-picrylhydrazyl, 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid), ferric-reducing power assay, and the inhibition capacity test on α-glucosidase and lipase were conducted to determine the antioxidant effect in vitro, as well as the reduction of blood sugar and lipids. Monthly variations in activities and components were determined by numeric analysis and comparison. Correlation analysis revealed that antioxidant effects are significantly correlated with the total flavonoids. The hierarchical cluster analysis of bioactivities and their contents indicates that October and November are the best harvesting months, which differs with the habitual collection of Hawk tea.

Natural Phytotherapeutic Antioxidants in the Treatment of Mercury Intoxication-A Review

Heavy metals taken into the organism can make the toxic effects on the metabolism in various ways. For example, they may interact with proteins to alter and inhibit their enzymatic and structural functions. Mercury is one of the toxic elements that are widely distributed in nature. Mercury toxicity poses a serious threat to human health. It is an element that causes oxidative stress to increase in individuals, leading to tissue damage. Oxidative stress is the result of the imbalance between the production of oxidative species and cellular antioxidant defense. Phytotherapy continues to play an important role in health care. Natural phytotherapeutic antioxidants, exhibit a broad sequence of biological impacts, including anti-oxidative stress, anti-aging, anti-toxicicity and anticancer. Many studies have also shown that the phytotherapeutic agents play an important role in the removal of mercury from the tissue and in reducing oxidative stress. Our goal in this review was to investigate alternative ways of extracting the mercury in the tissue.

Melatonin inhibits rotenone-induced SH-SY5Y cell death via the downregulation of Dynamin-Related Protein 1 expression

Previous studies have shown that melatonin can protect cells against rotenone-induced cell death. Yet, the mechanism involved in this protection requires further research. In this study, we aimed to further investigate the effects of melatonin on inhibiting rotenone-induced SH-SY5Y cells and the underlying molecular mechanisms. Human neuroblastoma SH-SY5Y cells were treated with 0.3 or 1μM rotenone for 6 or 12h. Cell viability was measured with an MTS assay, the mitochondrial membrane potential was determined with a Rhodamine 123 staining assay, and the protein expression levels of the markers of autophagy, including cytochrome C release (Cyt C), light chain 3B (LC3 B) and Dynamin-Related Protein 1 (Drp1) were analyzed by western blotting. The co-localization of Drp1 and TOM20 proteins in the mitochondria of SH-SY5Y cells was measured by immunofluorescence coupled with confocal microscopy and the overexpression of the Drp1 gene was then conducted. The viability and expression levels of Cyt C and LC3 B in rotenone and melatonin + rotenone-treated Drp1-overexpressed SH-SY5Y cells were analyzed with MTS and western blotting, respectively. We found that rotenone effectively induced SH-SY5Y cell death by causing mitochondrial dysfunction and increasing Cyt C expression. Drp1 expression and its regulation of mitochondrial translocation mediated the rotenone-induced cell death and melatonin inhibited this process. Overexpression of Drp1 protein attenuated melatonin's inhibition of rotenone-induced SH-SY5Y cell death. In conclusion, melatonin effectively inhibits rotenone-induced neuronal cell death via the regulation of Drp1 expression.

Dieldrin-induced neurotoxicity involves impaired mitochondrial bioenergetics and an endoplasmic reticulum stress response in rat dopaminergic cells

Mitochondria are sensitive targets of environmental chemicals. Dieldrin (DLD) is an organochlorine pesticide that remains a human health concern due to high lipid bioaccumulation, and it has been epidemiologically associated to an increased risk for Parkinson's disease (PD). As mitochondrial dysfunction is involved in the etiology of PD, this study aimed to determine whether DLD impaired mitochondrial bioenergetics in dopaminergic cells. Rat immortalized dopaminergic N27 cells were treated for 24 or 48h with one dose of either a solvent control, 2.5, 25, or 250μM DLD. Dopaminergic cells treated with 250μM DLD showed increased Casp3/7 activity at 24 and 48h. DLD also caused a dose dependent reduction in cell viability of ∼25-30% over 24h. No significant effects on cell viability, apoptosis, nor cytotoxicity were detected at 24 or 48h with 2.5μM DLD. Following a 24h exposure to 2.5 and 25μM DLD, viable cells were subjected to a mitochondrial stress test using the Seahorse XFe24 Extracellular Flux Analyzer. Following three independent experiments conducted for rigor, dopaminergic cells that were treated with 2.5 and 25μM DLD consistently showed a reduction in maximum respiration and spare capacity compared to the control group. Molecular responses were measured to determine mechanisms of DLD-induced mitochondrial dysfunction. There were no changes in transcripts associated with mitochondrial membrane potential and permeability (e.g. Ant, Hk1, Tspo, Vdac), nor PI3 K/Akt/mTor signaling or mitochondrial-associated apoptotic factors (Bax, Bcl2, Casp3). However, transcript levels for Chop/Gadd153 (DNA Damage Inducible Transcript 3), an apoptotic gene activated following endoplasmic reticulum (ER) stress, were 3-fold higher in N27 cells treated with DLD, suggesting that DLD-induced mitochondrial dysfunction is related to ER stress. Dopamine cells were also assessed for changes in tyrosine hydroxylase (TH) protein, which did not differ among treatments. This study demonstrates that DLD impairs oxidative respiration in dopamine cells, and ER stress is hypothesized to be associated with the DLD-induced mitochondrial dysfunction. This is important as ER stress is also linked to PD. This study presents mechanistic insight into pesticide-induced mitochondrial dysfunction using a chemical that is reported to be associated to a higher risk for neurodegenerative disease.

A H2O2-Responsive Theranostic Probe for Endothelial Injury Imaging and Protection

Overproduction of H₂O₂ causes oxidative stress and is the hallmark of vascular diseases. Tracking native H₂O₂ in the endothelium is therefore indispensable to gain fundamental insights into this pathogenesis. Previous fluorescent probes for H₂O₂ imaging were generally arylboronates which were decomposed to emissive arylphenols in response to H₂O₂. Except the issue of specificity challenged by peroxynitrite, boric acid by-produced in this process is actually a waste with unknown biological effects. Therefore, improvements could be envisioned if a therapeutic agent is by-produced instead. Herein, we came up with a "click-to-release-two" strategy and demonstrate that dual functional probes could be devised by linking a fluorophore with a therapeutic agent via a H₂O₂-responsive bond. As a proof of concept, probe AP consisting of a 2-(2'-hydroxyphenyl) benzothiazole fluorophore and an aspirin moiety has been prepared and confirmed for its theranostic effects. This probe features high specificity towards H₂O₂ than other reactive species including peroxynitrite. Its capability to image and ameliorate endothelial injury has been verified both in vitro and in vivo. Noteworthy, as a result of its endothelial-protective effect, AP also works well to reduce thrombosis formation in zebrafish model.

Sulforaphane Promotes Mitochondrial Protection in SH-SY5Y Cells Exposed to Hydrogen Peroxide by an Nrf2-Dependent Mechanism

Sulforaphane (SFN; C₆H₁₁NOS₂) is an isothiocyanate found in cruciferous vegetables, such as broccoli, kale, and radish. SFN exhibits antioxidant, anti-apoptotic, anti-tumor, and anti-inflammatory activities in different cell types. However, it was not previously demonstrated whether and how this natural compound would exert mitochondrial protection experimentally. Therefore, we investigated here the effects of a pretreatment (for 30 min) with SFN at 5 μM on mitochondria obtained from human neuroblastoma SH-SY5Y cells exposed to hydrogen peroxide (H₂O₂) at 300 μM for 24 h. We found that SFN prevented loss of viability in H₂O₂-treated SH-SY5Y cells. Furthermore, SFN decreased lipid peroxidation, protein carbonylation, and protein nitration in mitochondrial membranes of H₂O₂-exposed cells. Importantly, SFN enhanced the levels of both cellular and mitochondrial glutathione (GSH). SFN also suppressed the H₂O₂-mediated inhibition of mitochondrial components involved in the maintenance of the bioenergetics state, such as aconitase, α-ketoglutarate dehydrogenase, and succinate dehydrogenase, as well as complexes I and V. Consequently, SFN prevented the decline induced by H₂O₂ on the levels of ATP in SH-SY5Y cells. Silencing of the nuclear factor erythroid 2-related factor 2 (Nrf2) transcription factor by using small interfering RNA (siRNA) abolished the mitochondrial and cellular protection elicited by SFN. Therefore, SFN abrogated the H₂O₂-induced mitochondrial impairment by an Nrf2-dependent manner.

Carnosic Acid Suppresses the H2O2-Induced Mitochondria-Related Bioenergetics Disturbances and Redox Impairment in SH-SY5Y Cells: Role for Nrf2

The phenolic diterpene carnosic acid (CA, C₂₀H₂₈O₄) exerts antioxidant, anti-inflammatory, anti-apoptotic, and anti-cancer effects in mammalian cells. CA activates the nuclear factor erythroid 2-related factor 2 (Nrf2), among other signaling pathways, and restores cell viability in several in vitro and in vivo experimental models. We have previously reported that CA affords mitochondrial protection against various chemical challenges. However, it was not clear yet whether CA would prevent chemically induced impairment of the tricarboxylic acid cycle (TCA) function in mammalian cells. In the present work, we found that a pretreatment of human neuroblastoma SH-SY5Y cells with CA at 1 μM for 12 h prevented the hydrogen peroxide (H₂O₂)-induced impairment of the TCA enzymes (aconitase, α-ketoglutarate dehydrogenase (α-KGDH), succinate dehydrogenase (SDH)) and abolished the inhibition of the complexes I and V and restored the levels of ATP by a mechanism associated with Nrf2. CA also exhibited antioxidant abilities by enhancing the levels of reduced glutathione (GSH) and decreasing the content oxidative stress markers (cellular 8-oxo-2'-deoxyguanosine (8-oxo-dG), and mitochondrial malondialdehyde (MDA), protein carbonyl, and 3-nitrotyrosine). Silencing of Nrf2 by small interfering RNA (siRNA) abrogated the protective effects elicited by CA in mitochondria of SH-SY5Y cells. Therefore, CA prevented the H₂O₂-triggered mitochondrial impairment by an Nrf2-dependent mechanism. The specific role of Nrf2 in ameliorating the function of TCA enzymes function needs further research.

Fluoxetine and the mitochondria: A review of the toxicological aspects

Fluoxetine (a selective serotonin reuptake inhibitor (SSRI)) is used as an antidepressant by modulating the levels of serotonin in the synaptic cleft. Nevertheless, fluoxetine also induces undesirable effects, such as anxiety, sexual dysfunction, sleep disturbances, and gastrointestinal impairments. Fluoxetine has been viewed as an agent that may interfere with cell fate by triggering apoptosis. On the other hand, fluoxetine intake has been associated with increased cancer risk. Nonetheless, data remain contradictory and no conclusions were taken. Several studies demonstrated that fluoxetine interacts with mitochondria triggering apoptosis and/or altering mitochondrial function by modulating the activity of respiratory chain components and enzymes of the Krebs cycle. Furthermore, fluoxetine affects mitochondria-related redox parameters in different experimental models. In this review, data demonstrating the effects of fluoxetine upon mammalian mitochondria are described and discussed, as well as several unsolved questions in this field of research are addressed. A separate section deals with future needs regarding the research involving the impact of fluoxetine treatment upon mitochondria and mitochondria-related signaling.

Epigenetic Treatment of Neuropsychiatric Disorders: Autism and Schizophrenia

Neuropsychiatric disorders are a heterogeneous group of conditions that often share underlying mitochondrial dysfunction and biological pathways implicated in their pathogenesis, progression, and treatment. To date, these disorders have proven notoriously resistant to molecular-targeted therapies, and clinical options are relegated to interventional types, which do not address the core symptoms of the disease. In this review, we discuss emerging epigenetic-driven approaches using novel acylcarnitine esters (carnitinoids) that act on master regulators of antioxidant and cytoprotective genes and mitophagic pathways. These carnitinoids are actively transported, mitochondria-localizing, biomimetic coenzyme A surrogates of short-chain fatty acids, which inhibit histone deacetylase and may reinvigorate synaptic plasticity and protect against neuronal damage. We outline these neuroprotective effects in the context of treatment of neuropsychiatric disorders such as autism spectrum disorder and schizophrenia.

Litchi chinensis: medicinal uses, phytochemistry, and pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Litchi chinensis Sonn. (Sapindaceae) has been widely used in many cultures for the treatment of cough, flatulence, stomach ulcers, diabetes, obesity, testicular swelling, hernia-like conditions, and epigastric and neuralgic pains. The ethnopharmacologial history of L. chinensis indicated that it possesses hypoglycemic, anticancer, antibacterial, anti-hyperlipidemic, anti-platelet, anti-tussive, analgesic, antipyretic, hemostatic, diuretic, and antiviral activities.

AIM OF THE REVIEW

The aim of this review is to provide up-to-date information on the botanical characterization, distribution, traditional uses, and chemical constituents, as well as the pharmacological activities and toxicity of L. chinensis. Moreover, the focus of this review is the possible exploitation of this plant to treat different diseases and to suggest future investigations.

MATERIALS AND METHODS

To provide an overview of the ethnopharmacology, chemical constituents, and pharmacological activities of litchi, and to reveal their therapeutic potentials and being an evidence base for further research works, information on litchi was gathered from scientific journals, books, and worldwide accepted scientific databases via a library and electronic search (PubMed, Elsevier, Google Scholar, Springer, Scopus, Web of Science, Wiley online library, and pubs.acs.org/journal/jacsat). All abstracts and full-text articles were examined. The most relevant articles were selected for screening and inclusion in this review.

RESULTS

A comprehensive analysis of the literature obtained through the above-mentioned sources confirmed that ethno-medical uses of L. chinensis have been recorded in China, India, Vietnam, Indonesia, and Philippines. Phytochemical investigation revealed that the major chemical constituents of litchi are flavonoids, sterols, triterpenens, phenolics, and other bioactive compounds. Crude extracts and pure compounds isolated from L. chinensis exhibited significant antioxidant, anti-cancer, anti-inflammatory, anti-microbial, anti-viral, anti-diabetic, anti-obesity, hepato-protective, and immunomodulatory activities. From the toxicological perspective, litchi fruit juice and extracts have been proven to be safe at a dose 1 g/kg.

CONCLUSIONS

Phytochemical investigations indicated that phenolics were the major bioactive components of L. chinensis with potential pharmacological activities. The ethnopharmacological relevance of L. chinensis is fully justified by the most recent findings indicating it is a useful medicinal and nutritional agent for treating a wide range of human disorders and aliments. Further investigations are needed to fully understand the mode of action of the active constituents and to fully exploit its preventive and therapeutic potentials.

Significance of antioxidant potential of plants and its relevance to therapeutic applications

Oxidative stress has been identified as the root cause of the development and progression of several diseases. Supplementation of exogenous antioxidants or boosting endogenous antioxidant defenses of the body is a promising way of combating the undesirable effects of reactive oxygen species (ROS) induced oxidative damage. Plants have an innate ability to biosynthesize a wide range of non-enzymatic antioxidants capable of attenuating ROS- induced oxidative damage. Several in vitro methods have been used to screen plants for their antioxidant potential, and in most of these assays they revealed potent antioxidant activity. However, prior to confirming their in vivo therapeutic efficacy, plant antioxidants have to pass through several physiopharmacological processes. Consequently, the findings of in vitro and in vivo antioxidant potential assessment studies are not always the same. Nevertheless, the results of in vitro assays have been irrelevantly extrapolated to the therapeutic application of plant antioxidants without undertaking sufficient in vivo studies. Therefore, we have briefly reviewed the physiology and redox biology of both plants and humans to improve our understanding of plant antioxidants as therapeutic entities. The applications and limitations of antioxidant activity measurement assays were also highlighted to identify the precise path to be followed for future research in the area of plant antioxidants.

Oxidative stress, mitochondrial damage and neurodegenerative diseases

Oxidative stress and mitochondrial damage have been implicated in the pathogenesis of several neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis. Oxidative stress is characterized by the overproduction of reactive oxygen species, which can induce mitochondrial DNA mutations, damage the mitochondrial respiratory chain, alter membrane permeability, and influence Ca²⁺ homeostasis and mitochondrial defense systems. All these changes are implicated in the development of these neurodegenerative diseases, mediating or amplifying neuronal dysfunction and triggering neurodegeneration. This paper summarizes the contribution of oxidative stress and mitochondrial damage to the onset of neurodegenerative eases and discusses strategies to modify mitochondrial dysfunction that may be attractive therapeutic interventions for the treatment of various neurodegenerative diseases.

Improvement of oxidative and metabolic parameters by cellfood administration in patients affected by neurodegenerative diseases on chelation treatment

Objective. This prospective pilot study aimed at evaluating the effects of therapy with antioxidant compounds (Cellfood, and other antioxidants) on patients affected by neurodegenerative diseases (ND), who displayed toxic metal burden and were subjected to chelation treatment with the chelating agent calcium disodium ethylenediaminetetraacetic acid (CaNa₂EDTA or EDTA). Methods. Two groups of subjects were studied: (a) 39 patients affected by ND and (b) 11 subjects unaffected by ND (controls). The following blood parameters were analyzed before and after three months' treatment with chelation + Cellfood or chelation + other antioxidants: oxidative status (reactive oxygen species, ROS; total antioxidant capacity, TAC; oxidized LDL, oxLDL; glutathione), homocysteine, vitamin B12, and folate. Results. After 3-months' chelation + Cellfood administration oxLDL decreased, ROS levels were significantly lower, and TAC and glutathione levels were significantly higher than after chelation + other antioxidants treatment, both in ND patients and in controls. Moreover, homocysteine metabolism had also improved in both groups. Conclusions. Chelation + Cellfood treatment was more efficient than chelation + other antioxidants improving oxidative status and homocysteine metabolism significantly in ND patients and controls. Although limited to a small number of cases, this study showed how helpful antioxidant treatment with Cellfood was in improving the subjects' metabolic conditions.

Novel therapeutic targets in depression and anxiety: antioxidants as a candidate treatment

There is growing evidence that the imbalance between oxidative stress and the antioxidant defense system may be associated with the development neuropsychiatric disorders, such as depression and anxiety. Major depression and anxiety are presently correlated with a lowered total antioxidant state and by an activated oxidative stress (OS) pathway. The classical antidepressants may produce therapeutic effects other than regulation of monoamines by increasing the antioxidant levels and normalizing the damage caused by OS processes. This chapter provides an overview of recent work on oxidative stress markers in the animal models of depression and anxiety, as well as patients with the aforementioned mood disorders. It is well documented that antioxidants can remove the reactive oxygen species (ROS) and reactive nitrogen species (RNS) through scavenging radicals and suppressing the OS pathway, which further protect against neuronal damage caused oxidative or nitrosative stress sources in the brain, hopefully resulting in remission of depression or anxiety symptoms. The functional understanding of the relationship between oxidative stress and depression and anxiety may pave the way for discovery of novel targets for treatment of neuropsychiatric disorders.