Oxidative toxicity in neurodegenerative diseases: role of mitochondrial dysfunction and therapeutic strategies

Pterocarpus soyauxii (Fabaceae) aqueous extract to prevent neuropsychiatric disorders associated with menopause by triggering ROS-dependent oxidative damage and inhibiting acetylcholinesterase, GABA-transaminase, and monoamine oxidase A: In vitro, in vivo, and in silico approaches

Pterocarpus soyauxii (PS) is traditionally used in Cameroon medicine to alleviate postmenopausal symptoms. Previous research has shown that it has tissue-selective potential and estrogen-mimetic effects on vaginal atrophy. Phytoestrogens like 7-O-acetyl formononetin, khrinone A, and 3',5'-dimethoxy-4-stilbenol were found in its water extract by UHPLC, but there is no evidence of its effects on neurological disorders linked to post-menopause (ND-PO). The study aimed to investigate the phytochemical profile of PS aqueous extract, assess its neuroprotective potential in rats, and explore possible underlying pathways. We used colorimetric assays to study the phytochemical profile of PS extract. Effects of the extract on behavioral parameters, neuronal signaling, and integrity in an 84-day ovariectomized rat model. Molecular docking was performed to assess the ability of 7-O-acetyl formononetin, an isoflavone contained in PS, to cross the BBB and its binding affinity to the active sites of AChE, MAO-A, and GABA-T. Besides, the anti-AChE/BChE, antioxidant, and anti-inflammatory effects of PS were assessed by in vitro tests. PS aqueous extract contains polyphenols (656.58 ± 9.18 mgEAG/100gMS), flavonoids (201.25 ± 5.52 mgEQ/100gDW), and tannins (18.42 ± 1.25 mg/100gDW). It slows down anxiety, depressive disorders, cellular disorganization, and neuronal death in the hippocampus, dentate gyrus, and neocortex. In silico modeling was a powerful tool to assess the 7-O-acetylformononetin's ability to cross the BBB and strongly bind and inhibit AChE, MAO-A, and GABA-T. Thus, by combining GABAergic, cholinergic, and serotoninergic modulation, PS aqueous extract also possesses remarkable anti-AChE/BChE in vitro and induces antioxidant and anti-inflammatory potential in macrophages. Such estromimetics, antioxidant, anti-inflammatory, cholinergic, and monoaminergic modulators represent promising activities to develop neuroprotective drugs with optimal therapeutic profiles for menopausal women.

Modulating autophagy and mitophagy as a promising therapeutic approach in neurodegenerative disorders

The high prevalence of neurodegenerative diseases has become a major public health challenge and is associated with a tremendous burden on individuals, society and federal governments worldwide. Protein misfolding and aggregation are the major pathological hallmarks of several neurodegenerative disorders. The cells have evolved several regulatory mechanisms to deal with aberrant protein folding, namely the classical ubiquitin pathway, where ubiquitination of protein aggregates marks their degradation via lysosome and the novel autophagy or mitophagy pathways. Autophagy is a catabolic process in eukaryotic cells that allows the lysosome to recycle the cell's own contents, such as organelles and proteins, known as autophagic cargo. Their most significant role is to keep cells alive in distressed situations. Mitophagy is also crucial for reducing abnormal protein aggregation and increasing organelle clearance and partly accounts for maintaining cellular homeostasis. Furthermore, substantial data indicate that any disruption in these homeostatic mechanisms leads to the emergence of several age-associated metabolic and neurodegenerative diseases. So, targeting autophagy and mitophagy might be a potential therapeutic strategy for a variety of health conditions.

Potential Neurotoxic Effects of Glioblastoma-Derived Exosomes in Primary Cultures of Cerebellar Neurons via Oxidant Stress and Glutathione Depletion

High-grade gliomas are the most fatal brain tumors. Grade 4 gliomas are called glioblastoma multiforme (GBM), which are associated with the poorest survival and a 5-year survival rate of less than 4%. Many patients with GBM developed concomitant cognitive dysfunctions and epilepsy. Although the cognitive decline is well defined in glioblastomas, the neurotoxic factors underlying this pathology are not well understood in GBM patients. In this study, we aimed to investigate whether GBM-derived exosomes play a role in neuronal toxicity. For this purpose, exosomes obtained from T98G and U373 GBM cells were applied to primary neuron culture at different concentrations. Subsequently, MTT, LDH, GSH, TAS, and TOS tests were performed. Both GBM-derived exosomes induced a dose-dependent and statistically significant increase of LDH release in cerebellar neurons. MTT assay revealed as both T98G and U373 GBM-derived exosomes induced dose-dependent neurotoxic effects in cerebellar neurons. To the best of our knowledge, this study is the first study demonstrating the toxic potential of GBM-derived exosomes to primary neurons, which may explain the peritumoral edema and cognitive decline in GBM patients.

Curcumin, the active substance of turmeric: its effects on health and ways to improve its bioavailability

Turmeric (Curcuma longa L.) is a spice utilized widely in India, China, and Southeast Asia as an aromatic stimulant, a food preservative, and coloring material. The commonly used names of turmeric are castor saffron, turmeric, and saffron root. Turmeric is a yellow-orange polyphenolic natural substance derived from C. longa rhizomes. It has been used to treat common inflammatory diseases, tumors, biliary diseases, anorexia, cough, topical wounds, diabetic injuries, liver disorders, rheumatism, and sinusitis. Extensive studies on the biological properties and pharmacological consequences of turmeric extracts have been conducted in recent years. Curcumin, the primary yellow biocomponent of turmeric, has anti-inflammatory, antioxidant, anticarcinogenic, antidiabetic, antibacterial, antiprotozoal, antiviral, antifibrotic, immunomodulatory, and antifungal properties. Defense assessment tests showed that curcumin is tolerated well at high doses, without adverse effects. Thus, curcumin is a highly active biological material with the potential to treat different diseases in modern medicine. This review article focuses on curcumin's biological characteristics. The most popular methods for curcumin encapsulation are also discussed. Several effective techniques and approaches have been proposed for curcuminoid capsulation, including nanocomplexing, gelation, complex coacervation, electrospraying, and solvent-free pH-driven encapsulation. This review also highlights curcumin's chemical properties, allowing the readers to expand their perspectives on its use in the development of functional products with health-promoting properties. © 2021 Society of Chemical Industry.

Activation of Nrf2 by methylene blue is associated with the neuroprotection against MPP+ induced toxicity via ameliorating oxidative stress and mitochondrial dysfunction

The neuropathological hallmark of Parkinson's disease (PD) is the preferential loss of dopaminergic neurons in the substantia nigra and presence of Lewy bodies in the dying neurons. Though specific molecular mechanisms for the neurodegeneration remains to be clarified, mitochondrial dysfunction and increased oxidative stress are major players associated with PD pathogenesis and these pathogenic mechanisms can be reproduced in cells and animals by application of various neurotoxins such as MPP⁺. In this study, we attempted to determine the neuroprotective effects of methylene blue (MB) against 1-methyl-4-phenylpyridinium (MPP⁺)-induced neurotoxicity, and to elucidate its action mechanism. We observed that MB attenuated MPP⁺-induced apoptotic cell death in SH-SY5Y cells and the mescencephalic dopaminergic neurons. In addition, MB protected the cells against MPP⁺-induced oxidative stress and mitochondrial dysfunction as evidenced by restoration of mitochondrial complex I activity and ATP levels, and attenuation of oxidative stress. Moreover, we demonstrated that MB induced antioxidant molecules, and activated Nrf2 pathway through AKT activation. These results indicate that MB protects the neurons from MPP⁺-induced toxicity through activation of antioxidant system, thereby reducing the oxidative stress and mitochondrial impairment, implying the potential use of MB in the treatment of neurodegenerative diseases such as PD.

NIPSNAP protein family emerges as a sensor of mitochondrial health

Since their discovery over two decades ago, the molecular and cellular functions of the NIPSNAP family of proteins (NIPSNAPs) have remained elusive until recently. NIPSNAPs interact with a variety of mitochondrial and cytoplasmic proteins. They have been implicated in multiple cellular processes and associated with different physiologic and pathologic conditions, including pain transmission, Parkinson's disease, and cancer. Recent evidence demonstrated a direct role for NIPSNAP1 and NIPSNAP2 proteins in regulation of mitophagy, a process that is critical for cellular health and maintenance. Importantly, NIPSNAPs contain a 110 amino acid domain that is evolutionary conserved from mammals to bacteria. However, the molecular function of the conserved NIPSNAP domain and its potential role in mitophagy have not been explored. It stands to reason that the highly conserved NIPSNAP domain interacts with a substrate that is ubiquitously present across all species and can perhaps act as a sensor for mitochondrial health.

Zataria multiflora and Pioglitazone Affect Systemic Inflammation and Oxidative Stress Induced by Inhaled Paraquat in Rats

The effects of Zataria multiflora (Z. multiflora) and pioglitazone (a PPAR-γ agonist) alone and in combination, on systemic inflammation and oxidative stress induced by inhaled paraquat (PQ) as a herbicide, which induced inflammation in rats, were examined. Rats were exposed to (1) saline (control) and (2) 54 mg/m³ PQ aerosols (8 times, every other day, each time for 30 min) without treatment or treated with (3 and 4) two doses of Z. multiflora (200 and 800 mg/kg/day), (5 and 6) two doses of pioglitazone (5 and 10 mg/kg/day), (7) low doses of Z.multiflora + pioglitazone, (Pio-5+Z-200 mg/kg/day) or (8) dexamethasone (0.03 mg/kg/day) for 16 days, after the last PQ exposure. Different variables were measured at the end of the treatment period. Exposure to PQ significantly increased total and differential white blood cells (WBC) counts, serum levels of nitrite (NO₂), malondialdehyde (MDA), interleukin- (IL) 17, and tumor necrosis factor alpha (TNF-α), but reduced thiol, superoxide dismutase (SOD), catalase (CAT), IL-10, and interferon-gamma (INF-γ) (p < 0.05 to p < 0.001). Most measured parameters were significantly improved in groups treated with either doses of the extract, pioglitazone, Pio-5+Z-200 mg/kg/day, or dexamethasone compared to the PQ group (p < 0.05 to p < 0.001). The combination of low doses of Pio-5+Z-200 mg/kg/day showed significantly higher effects compared to each one alone (p < 0.05 to p < 0.001). Systemic oxidative stress and inflammation due to inhaled PQ were improved by Z. multiflora and pioglitazone. Higher effects of Pio-5+Z-200 mg/kg/day compared to each one alone suggest modulation of PPAR-γ receptors by the plant extract, but further studies using PPAR-γ antagonists need to be done in this regard.

Improvement of Oxidative Stress and Mitochondrial Dysfunction by β-Caryophyllene: A Focus on the Nervous System

Mitochondrial dysfunction results in a series of defective cellular events, including decreased adenosine triphosphate (ATP) production, enhanced reactive oxygen species (ROS) output, and altered proteastasis and cellular quality control. An enhanced output of ROS may damage mitochondrial components, such as mitochondrial DNA and elements of the electron transport chain, resulting in the loss of proper electrochemical gradient across the mitochondrial inner membrane and an ensuing shutdown of mitochondrial energy production. Neurons have an increased demand for ATP and oxygen, and thus are more prone to damage induced by mitochondrial dysfunction. Mitochondrial dysfunction, damaged electron transport chains, altered membrane permeability and Ca²⁺ homeostasis, and impaired mitochondrial defense systems induced by oxidative stress, are pathological changes involved in neurodegenerative disorders. A growing body of evidence suggests that the use of antioxidants could stabilize mitochondria and thus may be suitable for preventing neuronal loss. Numerous natural products exhibit the potential to counter oxidative stress and mitochondrial dysfunction; however, science is still looking for a breakthrough in the treatment of neurodegenerative disorders. β-caryophyllene is a bicyclic sesquiterpene, and an active principle of essential oils derived from a large number of spices and food plants. As a selective cannabinoid receptor 2 (CB2) agonist, several studies have reported it as possessing numerous pharmacological activities such as antibacterial (e.g., Helicobacter pylori), antioxidant, anti-inflammatory, analgesic (e.g., neuropathic pain), anti-neurodegenerative and anticancer properties. The present review mainly focuses on the potential of β-caryophyllene in reducing oxidative stress and mitochondrial dysfunction, and its possible links with neuroprotection.

Biochanin A Attenuates Ovariectomy-Induced Cognition Deficit via Antioxidant Effects in Female Rats

Background: Impairment of memory and cognition is one of the major symptoms in women with postmenopausal disorders due to estrogen deficiency, which accounts for the much higher prevalence of Alzheimer’s disease in females. Biochanin A (BCA), a natural phytoestrogen, has been reported to protect neurons against ischemic brain injury. However, the neuroprotective effects of BCA in the postmenopausal-like model of ovariectomized (OVX) rats remain to be investigated.

Methods: All the rats except for the sham group underwent the resection of bilateral ovaries. Seven days after the OVX surgery, rats were randomly divided into six groups: sham, OVX, OVX + BCA (5 mg/kg), OVX + BCA (20 mg/kg), OVX + BCA (60 mg/kg), and OVX + estradiol (E2; 0.35 mg/kg), which were administrated daily by gavage for 12 weeks. Learning and memory were examined using the Morris water-maze test before the end of the experiment. Morphological changes of the rat hippocampus were observed by HE staining and electron microscopy. Malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) in the hippocampus were measured. The effect of BCA on cell viability was measured in the presence of hydrogen peroxide (H₂O₂) using CCK8. Flow cytometry was used to measure neuronal apoptosis and reactive oxygen species (ROS) induced by H₂O₂. Expression of Bcl-2, Bax, and Caspase-3 was determined by Western blotting using hippocampal tissues and primary cultures of hippocampal neurons.

Results: Chronic treatment with BCA mimicked the ability of E2 to reverse the deficit of learning and memory in the Morris water-maze test in OVX rats. BCA normalized OVX-induced morphological changes as revealed by HE staining and electron microscopy. In addition, BCA significantly decreased the levels of MDA, the biomarker of oxidative damage, and increased the activity of the intracellular antioxidant enzymes SOD and GSH-Px in OVX rats. Further, in primary cultures of hippocampal neurons, BCA reversed H₂O₂-induced decreases in cell viability and accumulation of ROS. Finally, BCA reversed OVX- or H₂O₂-induced increases in Bax and Caspase-3 and decreases in Bcl-2 in the hippocampus and primary cultures of hippocampal neurons.

Conclusion: These results suggest that BCA improves memory through its neuroprotective properties in the brain under the circumstance of estrogen deficiency and can be used for treatment of memory loss in postmenopausal women.

Metabolic Changes in Brain Slices over Time: a Multiplatform Metabolomics Approach

Brain slice preparations are widely used for research in neuroscience. However, a high-quality preparation is essential and there is no consensus regarding stable parameters that can be used to define the status of the brain slice preparation after its collection at different time points. Thus, it is critical to fully characterize the experimental conditions for ex vivo studies using brain slices for electrophysiological recording. In this study, we used a multiplatform (LC-MS and GC-MS) untargeted metabolomics-based approach to shed light on the metabolome and lipidome changes taking place at different time intervals during the brain slice preparation process. We have found significant modifications in the levels of 300 compounds, including several lipid classes and their derivatives, as well as metabolites involved in the GABAergic pathway and the TCA cycle. All these preparation-dependent changes in the brain biochemistry related to the time interval should be taken into consideration for future studies to facilitate non-biased interpretations of the experimental results.

Fine-Tuning the Biological Profile of Multitarget Mitochondriotropic Antioxidants for Neurodegenerative Diseases

Neurotransmitter depletion and mitochondrial dysfunction are among the multiple pathological events that lead to neurodegeneration. Following our previous studies related with the development of multitarget mitochondriotropic antioxidants, this study aims to evaluate whether the π-system extension on the chemical scaffolds of AntiOXCIN2 and AntiOXCIN3 affects their bioactivity and safety profiles. After the synthesis of four triphenylphosphonium (TPP⁺) conjugates (compounds 2–5), we evaluated their antioxidant properties and their effect on neurotransmitter-metabolizing enzymes. All compounds were potent equine butyrylcholinesterase (eqBChE) and moderate electric eel acetylcholinesterase (eeAChE) inhibitors, with catechols 4 and 5 presenting lower IC₅₀ values than AntiOXCIN2 and AntiOXCIN3, respectively. However, differences in the inhibition potency and selectivity of compounds 2–5 towards non-human and human cholinesterases (ChEs) were observed. Co-crystallization studies with compounds 2–5 in complex with human ChEs (hChEs) showed that these compounds exhibit different binging modes to hAChE and hBChE. Unlike AntiOXCINs, compounds 2–5 displayed moderate human monoamine oxidase (hMAO) inhibitory activity. Moreover, compounds 4 and 5 presented higher ORAC-FL indexes and lower oxidation potential values than the corresponding AntiOXCINs. Catechols 4 and 5 exhibited broader safety windows in differentiated neuroblastoma cells than benzodioxole derivatives 2 and 3. Compound 4 is highlighted as a safe mitochondria-targeted antioxidant with dual ChE/MAO inhibitory activity. Overall, this work is a contribution for the development of dual therapeutic agents addressing both mitochondrial oxidative stress and neurotransmitter depletion.

Unfolding Nrf2 in diabetes mellitus

In spite of much awareness, diabetes mellitus continues to remain one of major reasons for mortality and morbidity rate all over the globe. Free radicals cause oxidative stress which is responsible for causing diabetes. The recent advancements in elucidation of ARE/keap1/Nrf2 pathway can help in better understanding of diabetes mellitus. Various clinical trials and animal studies have shown the promising effect of Nrf2 pathway in reversing diabetes by counteracting with the oxidative stress produced. The gene is known to dissociate from Keap1 on coming in contact with such stresses to show preventive and prognosis effect. The Nrf2 gene has been marked as a molecular player in dealing with wide intracellular as well as extracellular cellular interactions in different diseases. The regulation of this gene gives some transcription factor that contain antioxidant response elements (ARE) in their promoter region and thus are responsible for encoding certain proteins involved in regulation of metabolic and detoxifying enzymes.

Carvacrol and Zataria multiflora influenced the PPARγ agonist effects on systemic inflammation and oxidative stress induced by inhaled paraquat in rat

OBJECTIVES

The effects of PPAR-γ agonist alone and in combination with carvacrol and Zataria multiflora on inhaled paraquat (PQ) induced-systemic inflammation and oxidative stress were examined.

MATERIALS AND METHODS

Control group exposed to normal saline aerosol, one group exposed to 54 mg/m3 PQ aerosol and four groups exposed to PQ aerosol and treated with 5 mg/kg/day pioglitazone, pioglitazone + 200 mg/kg/day Z. multiflora extract, pioglitazone + 20 mg/kg/day carvacrol, and 0.03 mg /kg/day dexamethasone for 16 days after the end of exposure to PQ were studied. Exposure to normal saline or PQ was performed every other days for 30 min (8 times). Different variables were measured after the end of treatment period.

RESULTS

PQ exposure significantly increased serum levels of NO2, MDA and IL-6 but dexreased CAT and IFN-γ levels and IFN-γ/IL-6 ratio compared to control group (P<0.01 to P<0.001). Treatment with pioglitazone only improved serum level of MDA (P<0.01). Treatment with combination of pioglitazone and carvacrol as well as treatment with dexamethasone improved all measured variables compared to PQ exposed group (P<0.05 to P<0.001). The effects of pioglitazone + Z. multiflura and pioglitazone + carvacrol on almost all measured variables were significantly higher than pioglitazone alone (P<0.05 to P<0.001).

CONCLUSION

The effects of combination therapy of pioglitazone with Z. multiflora or carvacrol on inhaled paraquat (PQ) induced-oxidative stress and systemic inflammation were higher than the effects of pioglitazone alone. These results suggested that the effects of the extract and carvacrol may mediated through PPAR-γ receptors.

Dehydroepiandrosterone (DHEA) and its Sulphate (DHEAS) in Alzheimer's Disease

BACKGROUND

Neurosteroids Dehydroepiandrosterone (DHEA) and Dehydroepiandrosterone Sulphate (DHEAS) are involved in many important brain functions, including neuronal plasticity and survival, cognition and behavior, demonstrating preventive and therapeutic potential in different neuropsychiatric and neurodegenerative disorders, including Alzheimer's disease.

OBJECTIVE

The aim of the article was to provide a comprehensive overview of the literature on the involvement of DHEA and DHEAS in Alzheimer's disease.

METHODS

PubMed and MEDLINE databases were searched for relevant literature. The articles were selected considering their titles and abstracts. In the selected full texts, lists of references were searched manually for additional articles.

RESULTS

We performed a systematic review of the studies investigating the role of DHEA and DHEAS in various in vitro and animal models, as well as in patients with Alzheimer's disease, and provided a comprehensive discussion on their potential preventive and therapeutic applications.

CONCLUSION

Despite mixed results, the findings of various preclinical studies are generally supportive of the involvement of DHEA and DHEAS in the pathophysiology of Alzheimer's disease, showing some promise for potential benefits of these neurosteroids in the prevention and treatment. However, so far small clinical trials brought little evidence to support their therapy in AD. Therefore, large-scale human studies are needed to elucidate the specific effects of DHEA and DHEAS and their mechanisms of action, prior to their applications in clinical practice.

Acetylresveratrol as a Potential Substitute for Resveratrol Dragged the Toxic Aldehyde to Inhibit the Mutation of Mitochondrial DNA

The aim of this study was to explore whether or not acetylresveratrol as a potential substitute for resveratrol dragged the toxic aldehyde to inhibit the mutation of mitochondrial DNA. The results revealed that the acetylresveratrol shifted ultraviolet peak of trans-crotonaldehyde from 316 to 311 nm. In mitochondria, the acetylresveratrol split the ultraviolet peak at 311 nm of trans-crotonaldehyde into 311 nm and 309 nm; the aldehyde Raman band of trans-crotonaldehyde was red shifted by the acetylresveratrol from 1689 to 1686 cm^-1 with obvious band decline; Raman bands at 1149 cm^-1, 1168 cm^-1, and 1325 cm^-1 of acetylresveratrol disappeared. In aldehyde dehydrogenase, the aldehyde Raman band of trans-crotonaldehyde was red shifted by the acetylresveratrol from 1689 to 1684 cm^-1 with band decline; Raman bands at 1150 cm^-1, 1168 cm^-1, and 1324 cm^-1 of acetylresveratrol declined. The weak acidic microenvironment was the best, for the acetylresveratrol dragged the toxic aldehyde of trans-crotonaldehyde. Compared with the resveratrol, the effect of the acetylresveratrol on the toxic aldehyde of trans-crotonaldehyde was very similar to that of the resveratrol. The acetylresveratrol is very suitable as a potential substitute for resveratrol dragged the toxic aldehyde to inhibit the mutation of mitochondrial DNA. Graphical Abstract In mitochondria, the Raman band of the toxic -CH=O of trans-crotonaldehyde (TCA) dragged by the Acetyl-Res from 1689 to 1686 cm^-1 with obvious band decline, while the Raman bands at 1149 cm^-1, 1168 cm^-1, and 1325 cm^-1 of the Acetyl-Res disappeared, respectively. The Acetyl-Res is very suitable as a potential substitute, for the Res dragged the toxic -CH=O of TCA to inhibit the mutation of mitochondrial DNA for anticancer.

Beneficial Effects of Theta-Burst Transcranial Magnetic Stimulation on Stroke Injury via Improving Neuronal Microenvironment and Mitochondrial Integrity

Recent work suggests that repetitive transcranial magnetic stimulation (rTMS) may beneficially alter the pathological status of several neurological disorders, although the mechanism remains unclear. The current study was designed to investigate the effects of rTMS on behavioral deficits and potential underlying mechanisms in a rat photothrombotic (PT) stroke model. From day 0 (3 h) to day 5 after the establishment of PT stroke, 5-min daily continuous theta-burst rTMS (3 pulses of 50 Hz repeated every 200 ms, intensity at 200 G) was applied on the infarct hemisphere. We report that rTMS significantly attenuated behavioral deficits and infarct volume after PT stroke. Further investigation demonstrated that rTMS remarkably reduced synaptic loss and neuronal degeneration in the peri-infarct cortical region. Mechanistic studies displayed that beneficial effects of rTMS were associated with robust suppression of reactive micro/astrogliosis and the overproduction of pro-inflammatory cytokines, as well as oxidative stress and oxidative neuronal damage especially at the late stage following PT stroke. Intriguingly, rTMS could effectively induce a shift in microglial M1/M2 phenotype activation and an A1 to A2 switch in astrocytic phenotypes. In addition, the release of anti-inflammatory cytokines and mitochondrial MnSOD in peri-infarct regions were elevated following rTMS treatment. Finally, rTMS treatment efficaciously preserved mitochondrial membrane integrity and suppressed the intrinsic mitochondrial caspase-9/3 apoptotic pathway within the peri-infarct cortex. Our novel findings indicate that rTMS treatment exerted robust neuroprotection when applied at least 3 h after ischemic stroke. The underlying mechanisms are partially associated with improvement of the local neuronal microenvironment by altering inflammatory and oxidative status and preserving mitochondrial integrity in the peri-infarct zone. These findings provide strong support for the promising therapeutic effect of rTMS against ischemic neuronal injury and functional deficits following stroke.

Ketogenic diet attenuates cerebellar atrophy progression in a subject with a biallelic variant at the ATAD3A locus

The ATPase AAA-domain protein 3 (ATAD3) is a ubiquitously expressed mitochondrial protein involved in mitochondrial dynamics, DNA-nucleoid structural organization, cholesterol transport and steroidogenesis. Mutations within the ancestral ATAD3A gene are strongly associated with neurological abnormalities due to alterations in the mitochondrial function and homeostasis. Here, we report the case of a subject diagnosed with developmental delay associated with ataxia and progressive atrophy of both cerebellar hemispheres and cerebellar vermis, despite exhibiting a normal biochemical profile. By whole exome sequencing, we identified two biallelic single nucleotide variants within the coding region of ATAD3A in the affected subject. Both variants were previously reported as monoallelic variants with uncertain clinical significance. Importantly, the variant ATAD3A c.251T>C leads to an amino acid change of a highly conserved residue across species and in silico analysis revealed structural alteration in the ATAD3A protein. Ketogenic diet was administered to the subject as a novel therapeutic approach. Notably, the treatment correlated with a reduction in cerebellum atrophy progression and the gradual enhancement of the subject’s physical skills, vitality and personal interactions. Thus, we report the first subject with a homozygous status for the ATAD3A c.251T>C (p.Thr84Met) variant. We propose that this mutation led to an alteration of the mitochondrial function, causing the neurological symptoms observed in the subject. The symptoms were partially alleviated following ketogenic diet, improving the subject’s quality of life.

Whole blood transcriptomic profiles can differentiate vulnerability to chronic low back pain

The mechanisms underlying the transition from acute to chronic pain remain unclear. Here, we sought to characterize the transcriptome associated with chronic low back pain as well as the transcriptome of the transition from acute to chronic low back pain. For the analysis, we compared the whole blood transcriptome of: (a) patients at the onset of low back pain who no longer had pain within 6 weeks after onset (acute) with patients who developed chronic low back pain at 6 months (chronic T5); and, (b) patients at the onset of low back pain (chronic T1) who developed chronic pain at 6 months with healthy pain-free (normal) controls. The majority of differentially expressed genes were protein coding. We illustrate a unique chronic low back pain transcriptome characterized by significant enrichment for known pain genes, extracellular matrix genes, and genes from the extended major histocompatibility complex (MHC) genomic locus. The transcriptome of the transition from acute to chronic low back pain was characterized by significant upregulation of antigen presentation pathway (MHC class I and II) genes and downregulation of mitochondrial genes associated with oxidative phosphorylation, suggesting a unique genomic signature of vulnerability to low back pain chronicity.

Tortuous Paths of Insulin Signaling and Mitochondria in Alzheimer's Disease

Due to the exponential growth of aging population worldwide, neurodegenerative diseases became a major public health concern. Among them, Alzheimer's disease (AD) prevails as the most common in the elderly, rendering it a research priority. After several decades considering the brain as an insulin-insensitive organ, recent advances proved a central role for this hormone in learning and memory processes and showed that AD shares a high number of features with systemic conditions characterized by insulin resistance. Mitochondrial dysfunction has also been widely demonstrated to play a major role in AD development supporting the idea that this neurodegenerative disease is characterized by a pronounced metabolic dysregulation. This chapter is intended to discuss evidence demonstrating the key role of insulin signaling and mitochondrial anomalies in AD.

Toxic target of trans-crotonaldehyde in mitochondria altered by diallyl disulfides for anti-myocardial ischemia

The purposes of this study were to probe spectral behaviors of the toxic targets in trans-crotonaldehyde (TCA) in mitochondria altered by diallyl disulfides (DADS) derived from garlic. Ultraviolet absorption spectra showed that when ethanol as a solvent, the DADS blue shifted the peak of TCA from 318 nm to 312 nm. In mitochondria, the DADS further blue displaced the peak of TCA from 312 nm to 308 nm. Raman spectra displayed that the SS of DADS directly interacted with the CC toxic target of TCA, then the CCC of DADS interacted with the CHO toxic target of TCA. When DADS to TCA was 1:2, the DADS was the most powerful for the removal of the CC and CHO toxic targets of TCA. Study suggested that the SS of DADS altered the CC toxic target of TCA, while the CCC of DADS eliminated the CHO toxic target of TCA via local electron delocalization. The above two together clearly depicted the spectral behaviors of the toxic targets of TCA in mitochondria altered by DADS. These results are of great significance and value to elucidate the effects of garlic organic polysulfide on myocardial ischemia for the extensive development and use of garlic extracts.

Radix Rehmanniae Extract Ameliorates Experimental Autoimmune Encephalomyelitis by Suppressing Macrophage-Derived Nitrative Damage

Multiple sclerosis (MS) is a neuroinflammatory disease in central nervous system (CNS) without effective treatment or medication yet. With high prevalence of MS patients worldwide and poor therapeutic outcome, seeking novel therapeutic strategy for MS is timely important. Radix Rehmanniae (RR), a typical Chinese Medicinal herb, has been used for neuroinflammatory diseases in Traditional Chinese Medicine for centuries. However, scientific evidence and underlying mechanisms of RR for MS are unclear. In this study, we tested the hypothesis that RR could attenuate the progress and severity of MS via suppressing macrophage-derived nitrative damage and inflammation by using experimental autoimmune encephalomyelitis (EAE) model for mimicking MS pathology. The results showed the RR treatment effectively ameliorated clinical disease severity, inhibited inflammation/demyelination in spinal cord, and alleviated CNS infiltration of encephalitogenic T cells and activated macrophages. Meanwhile, RR possessed bioactivities of scavenging ONOO- and reducing the expression of iNOS and NADPH oxidases in the spinal cords of the EAE mice. Furthermore, RR treatment suppressed nuclear factor-κB (NF-κB) signaling pathway in the splenocytes of EAE mice. The in vitro experiments on macrophages and neuronal cells exerted consistent results with the in vivo animal experiments. Taken together, we conclude that Radix Rehmanniae extract has therapeutic values for ameliorating EAE/MS pathological process and disease severity and its underlying mechanisms are associated with anti-inflammation and inhibiting macrophage-derived nitrative damages. Further study could yield novel promising therapeutic agent for multiple sclerosis.

Bioconversion of Corticosterone into Corticosterone-Glucoside by Glucosyltransferase

Glucosylation of the 21-hydroxyl group of glucocorticoid changes its solubility into hydrophilicity from hydrophobicity and, as with glucocorticoid glucuronides as a moving object in vivo, it is conceivable that it exhibits the same behavior. Therefore, glucosylation to the 21-hydroxyl group while maintaining the 11β-hydroxyl group is particularly important, and glucosylation of corticosterone was confirmed by high-resolution mass spectrometry and 1D (¹H and ¹³C) and 2D (COSY, ROESY, HSQC-DEPT and HMBC) NMR. Moreover, the difference in bioactivity between corticosterone and corticosterone 21-glucoside was investigated in vitro. Corticosterone 21-glucoside showed greater neuroprotective effects against H₂O₂-induced cell death and reactive oxygen species (ROS) compared with corticosterone. These results for the first time demonstrate that bioconversion of corticosterone through the region-selective glucosylation of a novel compound can present structural potential for developing new neuroprotective agents.

In vitro anticholinesterase, antimonoamine oxidase and antioxidant properties of alkaloid extracts from kola nuts (Cola acuminata and Cola nitida)

Background

The development of cholinesterase (ChE) and monoamine oxidase (MAO) inhibitors for management of neurodegenerative diseases such as Alzheimer’s disease (AD) has come with their undesirable side effects. Hence, research for potent but natural ChE and MAO inhibitors with little or no side effects is essential. This study investigated the potentials of alkaloid extracts from two Cola species as nutraceuticals for prevention and management of AD.

Methods

Alkaloid extracts were obtained from two Cola species (Cola nitida [KN] and Cola acuminata [KA]) by solvent extraction method. The extracts were characterized for their alkaloid contents using gas chromatography (GC). The effects of the extracts on ChE and MAO activities were investigated in vitro. Also, the extracts’ ability to inhibit Fe2+-induced lipid peroxidation in rat brain homogenate, scavenge DPPH and OH radicals, as well as chelate Fe2+ were determined.

Results

GC characterization revealed the presence of augustamine and undulatine as the predominant alkaloids in the extracts. There was no significant (P > 0.05) difference in the inhibitory effects of the extracts on ChE activities. However, KA extract exhibited significantly higher (P < 0.05) MAO inhibitory effect than KN. Also, KA extract inhibited Fe2+- induced malondialdehyde (MDA) production in rat brain homogenate more significantly than KN, while there was no significant difference in DPPH and OH radicals scavenging, as well as Fe2+-chelating abilities of the extracts.

Conclusions

Our findings revealed that KN and KA alkaloid extracts exhibited significant effect in vitro on biological pathways that may contribute to neuroprotection for the management of neurodegenerative diseases.

The Effect of Associated Parkinsonism on Rehabilitation in Stroke Patients: A Case Series

Stroke and Parkinson’s disease are 2 major causes of movement impairment and a decreased ability to perform daily activities. The aim of this case series was to demonstrate the difficulty of rehabilitation in stroke patients with accompanying parkinsonism. Four stroke patients with parkinsonism who underwent rehabilitation at the Physical Medicine and Rehabilitation Clinic between March and May of 2016 were evaluated. The Standardized Mini-Mental State Examination (SMMSE), the Functional Independence Measure (FIM), the Barthel Index (BI), the Berg Balance Scale (BBS), and the Stroke Impact Scale version 3.0 (SIS) were used in the assessment. Of the 4 patients, 3 were female, and the mean age was 74.5±9.3 years. The mean hospital stay was 19±5.3 days. The initial test scores recorded were low, and they remained low at the time of discharge. After rehabilitation, the mean FIM score in the group was 42% of the maximum possible score, the mean SMMSE was 55%, the BI was 18%, the BBS was 0.08%, and the SIS was 25%. Three patients required a wheelchair, and 1 patient could ambulate with a walker at discharge. A stroke accompanied by parkinsonism negatively affects mobility and functional status, primarily through the deterioration of balance. In this study, cognitive function was reduced to half of the maximum, and the balance and function loss was more than 50%. Barthel index; berg balance scale; functional independence measure; mini-mental state examination; parkinsonism; stroke; stroke impact scale.

Time courses of post-injury mitochondrial oxidative damage and respiratory dysfunction and neuronal cytoskeletal degradation in a rat model of focal traumatic brain injury

Traumatic brain injury (TBI) results in rapid reactive oxygen species (ROS) production and oxidative damage to essential brain cellular components leading to neuronal dysfunction and cell death. It is increasingly appreciated that a major player in TBI-induced oxidative damage is the reactive nitrogen species (RNS) peroxynitrite (PN) which is produced in large part in injured brain mitochondria. Once formed, PN decomposes into highly reactive free radicals that trigger membrane lipid peroxidation (LP) of polyunsaturated fatty acids (e.g. arachidonic acid) and protein nitration (3-nitrotyrosine, 3-NT) in mitochondria and other cellular membranes causing various functional impairments to mitochondrial oxidative phosphorylation and calcium (Ca2+) buffering capacity. The LP also results in the formation of neurotoxic reactive aldehyde byproducts including 4-hydroxynonenal (4-HNE) and propenal (acrolein) which exacerbates ROS/RNS production and oxidative protein damage in the injured brain. Ultimately, this results in intracellular Ca2+ overload that activates proteolytic degradation of α-spectrin, a neuronal cytoskeletal protein. Therefore, the aim of this study was to establish the temporal evolution of mitochondrial dysfunction, oxidative damage and cytoskeletal degradation in the brain following a severe controlled cortical impact (CCI) TBI in young male adult rats. In mitochondria isolated from an 8 mm diameter cortical punch including the 5 mm wide impact site and their respiratory function studied ex vivo, we observed an initial decrease in complex I and II mitochondrial bioenergetics within 3 h (h). For complex I bioenergetics, this partially recovered by 12-16 h, whereas for complex II respiration the recovery was complete by 12 h. During the first 24 h, there was no evidence of an injury-induced increase in LP or protein nitration in mitochondrial or cellular homogenates. However, beginning at 24 h, there was a gradual secondary decline in complex I and II respiration that peaked at 72 h. post-TBI that coincided with progressive peroxidation of mitochondrial and cellular lipids, protein nitration and protein modification by 4-HNE and acrolein. The oxidative damage and respiratory failure paralleled an increase in Ca2+-induced proteolytic degradation of the neuronal cytoskeletal protein α-spectrin indicating a failure of intracellular Ca2+ homeostasis. These findings of a surprisingly delayed peak in secondary injury, suggest that the therapeutic window and needed treatment duration for certain antioxidant treatment strategies following CCI-TBI in rodents may be longer than previously believed.

Horseradish and radish peroxidases eaten with fish could help explain observed associations between fish consumption and protection from age-related dementia

A juxtaposition of regional cuisines and recent prospective studies of fish consumption in China and Japan points to fresh horseradish and/or radish (HRR) as possible contributors to delaying age-related dementia. The hypothesis is that the inverse association found sometimes between fish intake and cognitive decline is partially due to exposure of the oral cavity to active peroxidases from HRR served in conjunction with fish. This hypothesis can be tested by specifically looking at whether HRR is consumed with fish and whether such HRR is prepared in a way that preserves activity of HRR peroxidases. It is possible that by putting active HRR peroxidases in their mouths, elderly people supplement their age-diminished salivary antioxidant capacity and break down additional hydrogen peroxide (H₂O₂) in the oral cavity before it can migrate into the brain, thus decreasing the incidence of brain cell death induction by chronically-elevated H₂O₂. Intentional exposure of the oral cavity to active HRR peroxidases could be a prophylactic for delaying dementia. Because vegetable peroxidases are inactivated by gastric juices, it will be difficult to obtain benefit from HRR peroxidases' antioxidant effect via ingestion in encapsulated dietary supplements.

Influences of ethanol on the structure of toxic trans-crotonaldehyde in mitochondria coming from rat myocardium

Inappropriate use of ethanol (EtOH) had led to noticeable health problems, but a beneficial phenomenon was found that EtOH displayed unique influences for toxic trans-crotonaldehyde (TCA) derived from mitochondrial lipid peroxidation. The influences of EtOH on the structure of TCA were systematically probed by UV-vis & Raman spectroscopy in the absence and presence of mitochondria, respectively. The maximum UV-vis peak at 301 nm of TCA was red shifted by hydroxyl (-OH) and methyl (-CH₃) of EtOH, respectively. Raman stretching band of aldehyde (-CH=O) of TCA (TCA-CH=O) was split by the -CH₃ of EtOH. The -CH₃ increased TCA-CH=O stretching frequency while the -OH induced it. The more exposed -OH, the less stretching frequency. The ectopic -CH₃ red shifted the UV-vis peak at 301 nm and Raman band of TCA-CH=O. In mitochondria, EtOH red shifted Raman stretching band of TCA-CH=O. Raman stretching bands of C-H, C-O and C-C of EtOH were red shifted, while Raman stretching bands of -CH₂ and C-C-O of EtOH disappeared. The paper unearths the influences of EtOH to trap and transform the structure of TCA-CH=O. This discovery has an important contribution to eliminate TCA in order to protect and repair mtDNA by means of the decrease of 8-oxoG.

Antibacterial, Anticancer and Neuroprotective Activities of Rare Actinobacteria from Mangrove Forest Soils

Mangrove is a complex ecosystem that contains diverse microbial communities, including rare actinobacteria with great potential to produce bioactive compounds. To date, bioactive compounds extracted from mangrove rare actinobacteria have demonstrated diverse biological activities. The discovery of three novel rare actinobacteria by polyphasic approach, namely Microbacterium mangrovi MUSC 115T, Sinomonas humi MUSC 117T and Monashia flava MUSC 78T from mangrove soils at Tanjung Lumpur, Peninsular Malaysia have led to the screening on antibacterial, anticancer and neuroprotective activities. A total of ten different panels of bacteria such as Methicillin-resistant Staphylococcus aureus (MRSA) ATCC 43300, ATCC 70069, Pseudomonas aeruginosa NRBC 112582 and others were selected for antibacterial screening. Three different neuroprotective models (hypoxia, oxidative stress, dementia) were done using SHSY5Y neuronal cells while two human cancer cells lines, namely human colon cancer cell lines (HT-29) and human cervical carcinoma cell lines (Ca Ski) were utilized for anticancer activity. The result revealed that all extracts exhibited bacteriostatic effects on the bacteria tested. On the other hand, the neuroprotective studies demonstrated M. mangrovi MUSC 115T extract exhibited significant neuroprotective properties in oxidative stress and dementia model while the extract of strain M. flava MUSC 78T was able to protect the SHSY5Y neuronal cells in hypoxia model. Furthermore, the extracts of M. mangrovi MUSC 115T and M. flava MUSC 78T exhibited anticancer effect against Ca Ski cell line. The chemical analysis of the extracts through GC-MS revealed that the majority of the compounds present in all extracts are heterocyclic organic compound that could explain for the observed bioactivities. Therefore, the results obtained in this study suggested that rare actinobacteria discovered from mangrove environment could be potential sources of antibacterial, anticancer and neuroprotective agents.

Mechanisms underlying melatonin-mediated prevention of fenvalerate-induced behavioral and oxidative toxicity in zebrafish

The neurotoxic effects attributed to the pesticide fenvalerate (FEN) are well-established. The aim of this study was to determine whether melatonin (MLT) was able to protect against FEN-induced behavior, oxidative stress, apoptosis, and neurogenesis using zebrafish (Danio rerio) model. Zebrafish exposed to 100 μg/L FEN for 120 h exhibited decreased swimming activity accompanied by downregulated expression of neurogenesis-related genes (Dlx2, Shha, Ngn1, Elavl3, and Gfap), suggesting that neurogenesis were impaired. In addition, FEN exposure significantly elevated oxidative stress as evidenced by increased malondialdehyde levels, as well as activities of Cu/Zn superoxide dismutase (Cu/Zn SOD), catalase, and glutathione peroxidase. Acridine orange staining demonstrated that embryos treated with FEN for 120 h significantly enhanced apoptosis mainly in the brain. FEN also produced upregulation of the expression of the pro-apoptotic genes (Bax, Fas, caspase 8, caspase 9, and caspase 3) and decreased expression of the anti-apoptotic gene Bcl-2. MLT significantly attenuated the FEN-mediated oxidative stress, modulated apoptotic-regulating genes, and diminished apoptotic responses. Further, MLT blocked the FEN-induced effects on swimming behavior as well as on neurogenesis-related genes. In conclusion, MLT protected against FEN-induced developmental neurotoxicity and apoptosis by inhibiting pesticide-mediated oxidative stress in zebrafish.

Parkinson's disease might increase the risk of cerebral ischemic lesions

BACKGROUND

Parkinson's disease (PD) is the second most common neurodegenerative disease in the elderly. Cerebrovascular diseases such as cerebral ischemic lesion (CIL) also commonly occur in elderly adults. However, previous studies on the relationship between PD and cerebrovascular disease have not found consistent results. Therefore, we conducted this study to evaluate whether or not PD is related to an increased prevalence of ischemic cerebrovascular lesions.

METHODS

This study recruited 241 patients with PD and 112 healthy controls (HCs). All subjects underwent brain magnetic resonance imaging and general neuropsychological tests. The motor severity of PD was evaluated according to the Hoehn and Yahr stage (HY stage), and the severity of CIL in all subjects was classified according to Fazekas grade. The PD patients were classified into two subgroups according to HY stage (Group 1 - HY 1, 2; Group 2 - HY 3 to 5).

RESULTS

Among all PD patients, 76% had small vessel disease, while 44% of all HCs had small vessel disease (p<0.001). Regarding the difference between the two subgroups according to motor severity, group 2 showed significantly higher Fazekas scale score and more severe CIL, indicating a higher prevalence of small vessel disease compared to group 1.

CONCLUSION

This study demonstrates that PD patients have a significantly higher prevalence of CIL compared to HCs. Therefore, although the present study is not a large-scale study, we cautiously suggest that PD can play an important role as a risk factor in the occurrence of ischemic cerebrovascular disease.

Morinda citrifolia mitigates rotenone-induced striatal neuronal loss in male Sprague-Dawley rats by preventing mitochondrial pathway of intrinsic apoptosis

OBJECTIVES

Parkinson disease (PD) is a neurodegenerative disorder affecting mainly the motor system, as a result of death of dopaminergic neurons in the substantia nigra pars compacta. The present scenario of research in PD is directed to identify novel molecules that can be administered individually or co-administered with L-Dopa to prevent the L-Dopa-Induced Dyskinesia (LID) like states that arise during chronic L-Dopa administration. Hence, in this study, we investigated whether Morinda citrifolia has therapeutic effects in rotenone-induced Parkinson's disease (PD) with special reference to mitochondrial dysfunction mediated intrinsic apoptosis.

METHODS

Male Sprague-Dawley rats were stereotaxically infused with rotenone (3 µg in both SNPc and VTA) and co-treated with the ethyl acetate extract of Morinda citrifolia and levodopa.

RESULTS

The results revealed that rotenone-induced cell death was reduced by MCE treatment as measured by decline in the levels of pro-apoptotic proteins. Moreover, MCE treatment significantly augmented the levels of anti-apoptotic Bcl2 and blocks the release of cytochrome c, thereby alleviating the rotenone-induced dopaminergic neuronal loss, as evidenced by tyrosine hydroxylase (TH) immunostaining in the striatum.

DISCUSSION

Taken together, the results suggest that Morinda citrifolia may be beneficial for the treatment of neurodegenerative diseases like PD.

Antioxidant and neuroprotective effects of Dictyophora indusiata polysaccharide in Caenorhabditis elegans

ETHNOPHARMACOLOGICAL RELEVANCE

Dictyophora indusiata is a medicinal mushroom traditionally used in China for a variety of conditions, including inflammatory and neural diseases. D. indusiata polysaccharides (DiPS) are shown to have in vitro antioxidant activity but in vivo evidence is lacking. This study aimes to explore the antioxidant capacity and related neuroptotective activities of DiPS using wild-type and neurodegenerative Caenorhabditis elegans models.

MATERIALS AND METHODS

The antioxidant capacities of DiPS were first determined using paraquat survival and Pgst-4::GFP expression assays in wild-type and transgenic C. elegans models, respectively, and then further investigated by determining reactive oxygen species (ROS) level, malondialdehyde (MDA) content and superoxide dismutase (SOD) activity as well as functional parameters of mitochondria. The activation of stress response transcription factors and neuroptotective activities were examined using nuclear localization and chemosensory behavioral assays in transgenic nematodes, respectively.

RESULTS

DiPS was shown not only to increase survival rate and reduce stress level under paraquat-induced oxidative conditions but also to decrease ROS and MDA levels and increase SOD activity in C. elegans models. Moreover, DiPS was also able to restore the functional parameters of mitochondria, including membrane potential and ATP content, in paraquat-stressed nematodes. In addition, nuclear translocation assays demonstrate that the stress response transcription factor DAF-16/FOXO was involved in the antioxidant activity of the polysaccharide. Further experiments reveal that DiPS was capable of reducing ROS levels and alleviating chemosensory behavior dysfunction in transgenic nematode models of neurodegenerative diseases mediated by polyglutamine and amyloid-β protein.

CONCLUSIONS

These findings demonstrate the antioxidant and neuroprotective activities of the D. indusiata polysaccharide DiPS in wild-type and neurodegenerative C. elegans models, and thus provide an important pharmacological basis for the therapeutic potential of D. indusiata in neurodegeneration.

Neuregulin-1 (Nrg1) signaling has a preventive role and is altered in the frontal cortex under the pathological conditions of Alzheimer's disease

Alzheimer's disease (AD), one of the neurodegenerative disorders that may develop in the elderly, is characterized by the deposition of β‑amyloid protein (Aβ) and extensive neuronal cell death in the brain. Neuregulin‑1 (Nrg1)‑mediated intercellular and intracellular communication via binding to ErbB receptors regulates a diverse set of biological processes involved in the development of the nervous system. In the present study, a linear correlation was identified between Nrg1 and phosphorylated ErbB (pNeu and pErbB4) receptors in a human cortical tissue microarray. In addition, increased expression levels of Nrg1, but reduced pErbB receptor levels, were detected in the frontal lobe of a patient with AD. Western blotting and immunofluorescence staining were subsequently performed to uncover the potential preventive role of Nrg1 in cortical neurons affected by the neurodegenerative processes of AD. It was observed that the expression of Nrg1 increased as the culture time of the cortical neurons progressed. In addition, H2O2 and Aβ1‑42, two inducers of oxidative stress and neuronal damage, led to a dose‑dependent decrease in Nrg1 expression. Recombinant Nrg1β, however, was revealed to exert a pivotal role in preventing oxidative stress and neuronal damage from occurring in the mouse cortical neurons. Taken together, these results suggest that changes in Nrg1 signaling may influence the pathological development of AD, and exogenous Nrg1 may serve as a potential candidate for the prevention and treatment of AD.

Antioxidative Properties and Effect of Quercetin and Its Glycosylated Form (Rutin) on Acetylcholinesterase and Butyrylcholinesterase Activities

This study sought to investigate the anticholinesterase and antioxidative properties of quercetin and its glycosylated conjugate, rutin. The in vitro inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities, inhibition of Fe2+-induced lipid peroxidation in rat’s brain homogenates, radicals scavenging, and Fe2+-chelating abilities of the flavonoids were investigated in vitro with concentrations of the samples ranging from 0.06 to 0.6 mM. Quercetin had significantly higher AChE and BChE inhibitory abilities than rutin. Quercetin also had stronger inhibition of Fe2+-induced lipid peroxidation in rat’s brain homogenates. Similarly, quercetin had higher radical scavenging abilities than rutin. Quercetin also had stronger Fe2+-chelating ability than rutin. The inhibition of cholinesterases and antioxidative properties are possible mechanisms by which the flavonoids can be used in the management of oxidative stress–induced neurodegeneration.

The role of modulation of antioxidant enzyme systems in the treatment of neurodegenerative diseases

Oxidative stress is a much-appreciated phenomenon associated with the progression of neurodegenerative diseases (NDDs) due to imbalances in redox homeostasis. The poor correlations between the in vitro benefits and clinical trials of direct radical scavengers have prompted research into indirect antioxidant enzymes such as Nrf2. Activation of Nrf2 leads to the upregulation of a myriad of cytoprotective and antioxidant enzymes/proteins. Traditionally, early Nrf2-activators were studied as chemoprotective agents. There is a consequential lack of clinical trials testing Nrf2 activation in NDDs. However, there is abundant evidence of their utility in pre-clinical studies. Herein, we review the endogenous Nrf2 regulatory pathway and avenues for targeting this pathway. Furthermore, we provide updated information on pre-clinical studies for natural and synthetic Nrf2 activators. On the basis of our findings, we posit that successful therapeutics for NDDs rely on the design of potent synthetic Nrf2 activators with a careful combination of other neuroprotective activities.

HIV-Tat Induces the Nrf2/ARE Pathway through NMDA Receptor-Elicited Spermine Oxidase Activation in Human Neuroblastoma Cells

Previously, we reported that HIV-Tat elicits spermine oxidase (SMO) activity upregulation through NMDA receptor (NMDAR) stimulation in human SH-SY5Y neuroblastoma cells, thus increasing ROS generation, which in turn leads to GSH depletion, oxidative stress, and reduced cell viability. In several cell types, ROS can trigger an antioxidant cell response through the transcriptional induction of oxidative stress-responsive genes regulated by the nuclear factor erythroid 2-related factor 2 (Nrf2). Here, we demonstrate that Tat induces both antioxidant gene expression and Nrf2 activation in SH-SY5Y cells, mediated by SMO activity. Furthermore, NMDAR is involved in Tat-induced Nrf2 activation. These findings suggest that the NMDAR/SMO/Nrf2 pathway is an important target for protection against HIV-associated neurocognitive disorders.

lncRNAs in Stress Response

All living organisms sense and respond to harmful changes in their intracellular and extracellular environment through complex signaling pathways that lead to changes in gene expression and cellular function in order to maintain homeostasis. Long non-coding RNAs (lncRNAs), a large and heterogeneous group of functional RNAs, play important roles in cellular response to stressful conditions. lncRNAs constitute a significant fraction of the genes differentially expressed in response to diverse stressful stimuli and, once induced, contribute to the regulation of downstream cellular processes, including feedback regulation of key stress response proteins. While many lncRNAs seem to be induced in response to a specific stress, there is significant overlap between lncRNAs induced in response to different stressful stimuli. In addition to stress-induced RNAs, several constitutively expressed lncRNAs also exert a strong regulatory impact on the stress response. Although our understanding of the contribution of lncRNAs to the cellular stress response is still highly rudimentary, the existing data point to the presence of a complex network of lncRNAs, miRNAs, and proteins in regulation of the cellular response to stress.

Differential induction of inflammatory cytokines and reactive oxygen species in murine peritoneal macrophages and resident fresh bone marrow cells by acute staphylococcus aureus infection: contribution of toll-like receptor 2 (TLR2)

Among the known Toll-like receptors (TLRs), Toll-like receptor 2 (TLR2) is a key sensor for detecting Staphylococcus aureus invasion. But the function of TLR2 during S. aureus infection in different cell populations is unclear. Two different cell subtypes were chosen to study the interaction of S. aureus with TLR2 because macrophages are extremely different from one compartment to another and their capacity to respond to live bacteria or bacterial products differs from one site to another. The contribution of TLR2 to the host innate response against acute live S. aureus infection and heat-killed S. aureus (HKSA) using anti-TLR2 antibody in murine peritoneal macrophages and resident fresh bone marrow cells has been investigated here. TLR2 blocking before infection induces the release of interleukin (IL)-10 by macrophages thereby inhibiting excessive production of oxidants by activating antioxidant enzymes. TLR2-blocked peritoneal macrophages showed impaired release of tumor necrosis factor-alpha (TNF-α), interferon-gamma (IFN-γ) and IL-6 in response to both live and heat-killed S. aureus infection except bone marrow cells. TLR2-mediated free radical production and killing of S. aureus were modulated by TLR2 blocking in peritoneal macrophages and resident bone marrow cells. This study supported that S. aureus persists in resident bone marrow cells in a state of quiescence.

Elemental changes in the hippocampal formation following two different formulas of ketogenic diet: an X-ray fluorescence microscopy study

The main purpose of the following study was the determination of elemental changes occurring within hippocampal formation as a result of high-fat and carbohydrate-restricted ketogenic diet (KD). To realize it, X-ray fluorescence microscopy was applied for topographic and quantitative analysis of P, S, K, Ca, Fe, Cu, Zn and Se in hippocampal formations taken from rats fed with two different KDs and naive controls. The detailed comparisons were done for sectors 1 and 3 of the Ammon's, the dentate gyrus and hilus of dentate gyrus. The results of elemental analysis showed that the KDs induced statistically significant changes in the accumulation of P, K, Ca, Zn and Se in particular areas of hippocampal formation and these alterations strongly depended on the composition of the diets. Much greater influence on the hippocampal areal densities of examined elements was found for the KD which was characterized by a lower content of carbohydrates, higher content of fats and increased proportion of unsaturated fatty acids. The levels of P, K and Zn decreased whilst those of Ca and Se increased as a result of the treatment with the KDs.

Antioxidant peroxiredoxin 6 protein rescues toxicity due to oxidative stress and cellular hypoxia in vitro, and attenuates prion-related pathology in vivo

Protein misfolding, mitochondrial dysfunction and oxidative stress are common pathomechanisms that underlie neurodegenerative diseases. In prion disease, central to these processes is the post-translational transformation of cellular prion protein (PrP(c)) to the aberrant conformationally altered isoform; PrP(Sc). This can trigger oxidative reactions and impair mitochondrial function by increasing levels of peroxynitrite, causing damage through formation of hydroxyl radicals or via nitration of tyrosine residues on proteins. The 6 member Peroxiredoxin (Prdx) family of redox proteins are thought to be critical protectors against oxidative stress via reduction of H2O2, hydroperoxides and peroxynitrite. In our in vitro studies cellular metabolism of SK-N-SH human neuroblastoma cells was significantly decreased in the presence of H2O2 (oxidative stressor) or CoCl2 (cellular hypoxia), but was rescued by treatment with exogenous Prdx6, suggesting that its protective action is in part mediated through a direct action. We also show that CoCl2-induced apoptosis was significantly decreased by treatment with exogenous Prdx6. We proposed a redox regulator role for Prdx6 in regulating and maintaining cellular homeostasis via its ability to control ROS levels that could otherwise accelerate the emergence of prion-related neuropathology. To confirm this, we established prion disease in mice with and without astrocyte-specific antioxidant protein Prdx6, and demonstrated that expression of Prdx6 protein in Prdx6 Tg ME7-animals reduced severity of the behavioural deficit, decreased neuropathology and increased survival time compared to Prdx6 KO ME7-animals. We conclude that antioxidant Prdx6 attenuates prion-related neuropathology, and propose that augmentation of endogenous Prdx6 protein represents an attractive adjunct therapeutic approach for neurodegenerative diseases.

Protective Effects of Propofol Against Methamphetamine-induced Neurotoxicity

CONTEXT

Methamphetamine (METH) is widely abused in worldwide. METH use could damage the dopaminergic system and induce neurotoxicity via oxidative stress and mitochondrial dysfunction. Propofol, a sedative-hypnotic agent, is known for its antioxidant properties. In this study, we used propofol for attenuating of METH-induced neurotoxicity in rats.

SUBJECTS AND METHODS

We used Wistar rats that the groups (six rats each group) were as follows: Control, METH (5 mg/kg IP), and propofol (5, 10 and 20 mg/kg, IP) was administered 30 min before METH. After 24 h, animals were killed, brain tissue was separated and the mitochondrial fraction was isolated, and oxidative stress markers were measured.

RESULTS

Our results showed that METH significantly increased oxidative stress markers such as lipid peroxidation, reactive oxygen species formation and glutathione oxidation in the brain, and isolated mitochondria. Propofol significantly inhibited METH-induced oxidative stress in the brain and isolated mitochondria. Mitochondrial function decreased dramatically after METH administration that propofol pretreatment significantly improved mitochondrial function. Mitochondrial swelling and catalase activity also increased after METH exposure but was significantly decreased with propofol pretreatment.

CONCLUSIONS

These results suggest that propofol prevented METH-induced oxidative stress and mitochondrial dysfunction and subsequently METH-induced neurotoxicity. Therefore, the effectiveness of this antioxidant should be evaluated for the treatment of METH toxicity and neurodegenerative disease.

Antioxidant activity of leaf extracts from different Hibiscus sabdariffa accessions and simultaneous determination five major antioxidant compounds by LC-Q-TOF-MS

Hibiscus sabdariffa has gained attention for its antioxidant activity. There are many accessions of H. sabdariffa in the world. However, information on the quantification of antioxidant compounds in different accessions is rather limited. In this paper, a liquid chromatography/quadrupole-time-of-flight mass spectrometry (LC-Q-TOF-MS) method for simultaneous determination of five antioxidant compounds (neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid, rutin, and isoquercitrin) in H. sabdariffa leaves was developed. The method was validated for linearity, sensitivity, precision, repeatability and accuracy. The validated method has been successfully applied for determination of the five analytes in eight accessions of H. sabdariffa. The eight accessions of H. sabdariffa were evaluated for their antioxidant activities by DPPH free radical scavenging assay. The investigated accessions of H. sabdariffa were rich in rutin and exhibited strong antioxidant activity. The two accessions showing the highest antioxidant activities were from Cuba (No. 2) and Taiwan (No. 5). The results indicated that H. sabdariffa leaves could be considered as a potential antioxidant source for the food industry. The developed LC-Q-TOF-MS method is helpful for quality control of H. sabdariffa.

MitProNet: A knowledgebase and analysis platform of proteome, interactome and diseases for mammalian mitochondria

Mitochondrion plays a central role in diverse biological processes in most eukaryotes, and its dysfunctions are critically involved in a large number of diseases and the aging process. A systematic identification of mitochondrial proteomes and characterization of functional linkages among mitochondrial proteins are fundamental in understanding the mechanisms underlying biological functions and human diseases associated with mitochondria. Here we present a database MitProNet which provides a comprehensive knowledgebase for mitochondrial proteome, interactome and human diseases. First an inventory of mammalian mitochondrial proteins was compiled by widely collecting proteomic datasets, and the proteins were classified by machine learning to achieve a high-confidence list of mitochondrial proteins. The current version of MitProNet covers 1124 high-confidence proteins, and the remainders were further classified as middle- or low-confidence. An organelle-specific network of functional linkages among mitochondrial proteins was then generated by integrating genomic features encoded by a wide range of datasets including genomic context, gene expression profiles, protein-protein interactions, functional similarity and metabolic pathways. The functional-linkage network should be a valuable resource for the study of biological functions of mitochondrial proteins and human mitochondrial diseases. Furthermore, we utilized the network to predict candidate genes for mitochondrial diseases using prioritization algorithms. All proteins, functional linkages and disease candidate genes in MitProNet were annotated according to the information collected from their original sources including GO, GEO, OMIM, KEGG, MIPS, HPRD and so on. MitProNet features a user-friendly graphic visualization interface to present functional analysis of linkage networks. As an up-to-date database and analysis platform, MitProNet should be particularly helpful in comprehensive studies of complicated biological mechanisms underlying mitochondrial functions and human mitochondrial diseases. MitProNet is freely accessible at http://bio.scu.edu.cn:8085/MitProNet.