Shared mechanisms of neurodegeneration in Alzheimer's disease and Parkinson's disease

Clinical Insights into Mitochondrial Neurodevelopmental and Neurodegenerative Disorders: Their Biosignatures from Mass Spectrometry-Based Metabolomics

Mitochondria are dynamic multitask organelles that function as hubs for many metabolic pathways. They produce most ATP via the oxidative phosphorylation pathway, a critical pathway that the brain relies on its energy need associated with its numerous functions, such as synaptic homeostasis and plasticity. Therefore, mitochondrial dysfunction is a prevalent pathological hallmark of many neurodevelopmental and neurodegenerative disorders resulting in altered neurometabolic coupling. With the advent of mass spectrometry (MS) technology, MS-based metabolomics provides an emerging mechanistic understanding of their global and dynamic metabolic signatures. In this review, we discuss the pathogenetic causes of mitochondrial metabolic disorders and the recent MS-based metabolomic advances on their metabolomic remodeling. We conclude by exploring the MS-based metabolomic functional insights into their biosignatures to improve diagnostic platforms, stratify patients, and design novel targeted therapeutic strategies.

Docosahexaenoic and Arachidonic Acids as Neuroprotective Nutrients throughout the Life Cycle

The role of docosahexaenoic acid (DHA) and arachidonic acid (AA) in neurogenesis and brain development throughout the life cycle is fundamental. DHA and AA are long-chain polyunsaturated fatty acids (LCPUFA) vital for many human physiological processes, such as signaling pathways, gene expression, structure and function of membranes, among others. DHA and AA are deposited into the lipids of cell membranes that form the gray matter representing approximately 25% of the total content of brain fatty acids. Both fatty acids have effects on neuronal growth and differentiation through the modulation of the physical properties of neuronal membranes, signal transduction associated with G proteins, and gene expression. DHA and AA have a relevant role in neuroprotection against neurodegenerative pathologies such as Alzheimer's disease and Parkinson's disease, which are associated with characteristic pathological expressions as mitochondrial dysfunction, neuroinflammation, and oxidative stress. The present review analyzes the neuroprotective role of DHA and AA in the extreme stages of life, emphasizing the importance of these LCPUFA during the first year of life and in the developing/prevention of neurodegenerative diseases associated with aging.

Fermented Soy Products: Beneficial Potential in Neurodegenerative Diseases

Fermented soybean products, such as cheonggukjang (Japanese natto), doenjang (soy paste), ganjang (soy sauce), and douchi, are widely consumed in East Asian countries and are major sources of bioactive compounds. The fermentation of cooked soybean with bacteria (Bacillus spp.) and fungi (Aspergillus spp. and Rhizopus spp.) produces a variety of novel compounds, most of which possess health benefits. This review is focused on the preventive and ameliorative potential of fermented soy foods and their components to manage neurodegenerative diseases, including Alzheimer's and Parkinson's diseases.

Clinical Relevance of [18F]Florbetaben and [18F]FDG PET/CT Imaging on the Management of Patients with Dementia

PET of β-Amyloid plaques (Aβ) using [¹⁸F]florbetaben ([¹⁸F]FBB) and [¹⁸F]fluorodeoxyglucose ([¹⁸F]FDG) increasingly aid clinicians in early diagnosis of dementia, including Alzheimer’s disease (AD), frontotemporal disease, dementia with Lewy bodies, and vascular dementia. The aim of this retrospective analysis was to evaluate clinical relevance of [¹⁸F]FBB, [¹⁸F]FDG PET and complimentary CSF measurements in patients with suspected dementia. In this study, 40 patients with clinically suspected or history of dementia underwent (1) measurement of Aβ peptides, total tau, and p-tau protein levels in the cerebrospinal fluid (CSF) compared with healthy controls (HC); (2) clinical and neuropsychological assessment, which included Consortium to Establish a Registry for Alzheimer’s Disease neuropsychological assessment battery (CERAD-NAB); (3) [¹⁸F]FBB and [¹⁸F]FDG PET imaging within an average of 3 weeks. The subjects were within 15 days stratified using PET, CSF measurements as HC, mild cognitive impaired (MCI) and dementia including Alzheimer´s disease. The predictive dementia-related cognitive decline values were supporting the measurements. PET images were evaluated visually and quantitatively using standard uptake value ratios (SUVR). Twenty-one (52.5%) subjects were amyloid-positive (Aβ+), with a median neocortical SUVR of 1.80 for AD versus 1.20 relative to the respective 19 (47.5 %) amyloid-negative (Aβ-) subjects. Moreover, the [¹⁸F]FDG and [¹⁸F]FBB confirmed within a sub-group of 10 patients a good complimentary role by correlation between amyloid pathology and brain glucose metabolism in 8 out of 10 subjects. The results suggest the clinical relevance for [¹⁸F]FBB combined with [¹⁸F]FDG PET retention and CFS measurements serving the management of our patients with dementia. Therefore, [¹⁸F]FBB combined with [¹⁸F]FDG PET is a helpful tool for differential diagnosis, and supports the patients’ management as well as treatment.

Data-driven biomarker analysis using computational omics approaches to assess neurodegenerative disease progression

The complexity of biological systems suggests that current definitions of molecular dysfunctions are essential distinctions of a complex phenotype. This is well seen in neurodegenerative diseases (ND), such as Alzheimer's disease (AD) and Parkinson's disease (PD), multi-factorial pathologies characterized by high heterogeneity. These challenges make it necessary to understand the effectiveness of candidate biomarkers for early diagnosis, as well as to obtain a comprehensive mapping of how selective treatment alters the progression of the disorder. A large number of computational methods have been developed to explain network-based approaches by integrating individual components for modeling a complex system. In this review, high-throughput omics methodologies are presented for the identification of potent biomarkers associated with AD and PD pathogenesis as well as for monitoring the response of dysfunctional molecular pathways incorporating multilevel clinical information. In addition, principles for efficient data analysis pipelines are being discussed that can help address current limitations during the experimental process by increasing the reproducibility of benchmarking studies.

CD33 rs3865444 as a risk factor for Parkinson's disease

BACKGROUND

Alzheimer's (AD) and Parkinson's diseases (PD) share a few elements of their clinical, pathological and genetic backgrounds. The CD33 rs3865444 has emerged as a strong genetic locus associated with AD through genome-wide association study (GWAS). However, little is known for its role in PD.

OBJECTIVE

To assess the role of CD33 rs3865444 on PD risk.

METHODS

We genotyped 358 patients with PD and 358 healthy controls for theCD33 rs3865444. Odds ratios (ORs) with the respective 95% confidence intervals (CIs)], were calculated with the SNPStats software, assuming five genetic models (co-dominant, dominant, recessive, over-dominant and log-additive), with the G allele as the reference allele.

RESULTS

The CD33 rs3865444 was associated with decreased PD risk in the dominant [GG vs GT + TT; OR (95% CI) = 0.61 (0.45-0.82), p = 0.001], the over-dominant [GG + TT vs GT; OR (95% CI) = 0.65 (0.48-0.89), p = 0.0061], log-additive [OR (95% CI) = 0.67 (0.52-0.86), p = 0.0014], and co-dominant [with overall p = 0.0043, and OR (95% CI) = 0.62 (0.45-0.84) for the TG genotype compared to the GG], modes of inheritance.

CONCLUSIONS

The CD33 rs3865444 is associated with decreased PD risk, and larger studies investigating the role of CD33 rs3865444 on PD are needed.

Proteomic Profiling of Cerebrum Mitochondria, Myelin Sheath, and Synaptosome Revealed Mitochondrial Damage and Synaptic Impairments in Association with 3 × Tg-AD Mice Model

Alzheimer's disease (AD) is the most common age-associated dementia with complex pathological hallmarks. Mitochondrion, synaptosome, and myelin sheath appear to be vulnerable and play a key role in the pathogenesis of AD. To clarify the early mechanism associated with AD, followed by subcellular components separation, we performed iTRAQ (isobaric tags for relative and absolute quantification)-based proteomics analysis to simultaneously investigate the differentially expressed proteins (DEPs) within the mitochondria, synaptosome, and myelin sheath in the cerebrum of the 6-month-old triple transgenic AD (3 × Tg-AD) and 6-month-old wild-type (WT) mice. A large number of DEPs between the AD and WT mice were identified. Most of them are related to mitochondria and synaptic dysfunction and cytoskeletal protein change. Differential expressions of Lrpprc, Nefl, and Sirpa were verified by Western blot analysis. The results suggest that decreased energy metabolism, impaired amino acid metabolism and neurotransmitter synthesis, increase compensatory fatty acid metabolism, up-regulated cytoskeletal protein expression, and oxidative stress are the early events of AD. Among these, mitochondrial damage, synaptic dysfunction, decreased energy metabolism, and abnormal amino acid metabolism are the most significant events. The results indicate that it is feasible to separate and simultaneously perform proteomics analysis on the three subcellular components.

Editorial to the Special Issue "Lipidomics and Neurodegenerative Diseases"

The contribution of dysregulation of lipid signaling and metabolism to neurodegenerative diseases including Alzheimer's and Parkinson's is the focus of this special issue. Here, the matter of three reviews and one research article is summarized.

Potential of Medicinal Plants as Neuroprotective and Therapeutic Properties Against Amyloid-β-Related Toxicity, and Glutamate-Induced Excitotoxicity in Human Neural Cells

Alzheimer's disease (AD) and Parkinson's disease (PD) are notorious neurodegenerative diseases amongst the general population. Being age-associated diseases, the prevalence of AD and PD is forecasted to rapidly escalate with the progressive aging population of the world. These diseases are complex and multifactorial. Among different events, amyloid β peptide (Aβ) induced toxicity is a well-established pathway of neuronal cell death, which plays a vital function in AD. Glutamate, the major excitatory transmitter, acts as a neurotoxin when present in excess at the synapses; this latter mechanism is termed excitotoxicity. It is hypothesised that glutamate-induced excitotoxicity contributes to the pathogenesis of AD and PD. No cure for AD and PD is currently available and the currently approved drugs available to treat these diseases have limited effectiveness and pose adverse effects. Indeed, plants have been a major source for the discovery of novel pharmacologically active compounds for distinct pathological conditions. Diverse plant species employed for brain-related disorders in traditional medicine are being explored to determine the scientific rationale behind their uses. Herein, we present a comprehensive review of plants and their constituents that have shown promise in reversing the (i) amyloid-β -related toxicity in AD models and (ii) glutamate-induced excitotoxicity in AD and PD models. This review summarizes information regarding the phytochemistry, biological and cellular activities, and clinical trials of several plant species in view to provide adequate scientific baseline information that could be used in the drug development process, thereby providing effective leads for AD and PD.

Is there a link between inorganic polyphosphate (polyP), mitochondria, and neurodegeneration?

Mitochondrial dysfunction - including increased apoptosis, calcium and protein dyshomeostasis within the organelle, and dysfunctional bioenergetics and oxidative status - is a common, early feature in all the major neurodegenerative diseases, including Alzheimer's Disease (AD) and Parkinson's Disease (PD). However, the exact molecular mechanisms that drive the organelle to dysfunction and ultimately to failure in these conditions are still not well described. Different authors have shown that inorganic polyphosphate (polyP), an ancient and well-conserved molecule, plays a key role in the regulation of mitochondrial physiology under basal conditions. PolyP, which is present in all studied organisms, is composed of chains of orthophosphates linked together by highly energetic phosphoanhydride bonds, similar to those found in ATP. This polymer shows a ubiquitous distribution, even if a high co-localization with mitochondria has been reported. It has been proposed that polyP might be an alternative to ATP for cellular energy storage in different organisms, as well as the implication of polyP in the regulation of many of the mitochondrial processes affected in AD and PD, including protein and calcium homeostasis. Here, we conduct a comprehensive review and discussion of the bibliography available regarding the role of polyP in the mitochondrial dysfunction present in AD and PD. Taking into account the data presented in this review, we postulate that polyP could be a valid, innovative and, plausible pharmacological target against mitochondrial dysfunction in AD and PD. However, further research should be conducted to better understand the exact role of polyP in neurodegeneration, as well as the metabolism of the polymer, and the effect of different lengths of polyP on cellular and mitochondrial physiology.

Hesperidin protects against behavioral alterations and loss of dopaminergic neurons in 6-OHDA-lesioned mice: the role of mitochondrial dysfunction and apoptosis

Hesperidin is a flavonoid glycoside that is frequently found in citrus fruits. Our group have demonstrated that hesperidin has neuroprotective effect in 6-hydroxydopamine (6-OHDA) model of Parkinson's disease (PD), mainly by antioxidant mechanisms. Although the pathophysiology of PD remains uncertain, a large body of evidence has demonstrated that mitochondrial dysfunction and apoptosis play a critical role in dopaminergic nigrostriatal degeneration. However, the ability of hesperidin in modulating these mechanisms has not yet been investigated. In the present study, we examined the potential of a 28-day hesperidin treatment (50 mg/kg/day, p.o.) in preventing behavioral alterations induced by 6-OHDA injection via regulating mitochondrial dysfunction, apoptosis and dopaminergic neurons in the substantia nigra pars compacta (SNpc) in C57BL/6 mice. Our results demonstrated that hesperidin treatment improved motor, olfactory and spatial memory impairments elicited by 6-OHDA injection. Moreover, hesperidin treatment attenuated the loss of dopaminergic neurons (TH+ cells) in the SNpc and the depletion of dopamine (DA) and its metabolities 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in the striatum of 6-OHDA-lesioned mice. Hesperidin also protected against the inhibition of mitochondrial respiratory chain complex-I, -IV and V, the decrease of Na + -K + -ATPase activity and the increase of caspase-3 and -9 activity in the striatum. Taken together, our findings indicate that hesperidin mitigates the degeneration of dopaminergic neurons in the SNpc by preventing mitochondrial dysfunction and modulating apoptotic pathways in the striatum of 6-OHDA-treated mice, thus improving behavioral alterations. These results provide new insights on neuroprotective mechanisms of hesperidin in a relevant preclinical model of PD.

Unraveling Targetable Systemic and Cell-Type-Specific Molecular Phenotypes of Alzheimer's and Parkinson's Brains With Digital Cytometry

Alzheimer's disease (AD) and Parkinson's disease (PD) are the two most common neurodegenerative disorders worldwide, with age being their major risk factor. The increasing worldwide life expectancy, together with the scarcity of available treatment choices, makes it thus pressing to find the molecular basis of AD and PD so that the causing mechanisms can be targeted. To study these mechanisms, gene expression profiles have been compared between diseased and control brain tissues. However, this approach is limited by mRNA expression profiles derived for brain tissues highly reflecting their degeneration in cellular composition but not necessarily disease-related molecular states. We therefore propose to account for cell type composition when comparing transcriptomes of healthy and diseased brain samples, so that the loss of neurons can be decoupled from pathology-associated molecular effects. This approach allowed us to identify genes and pathways putatively altered systemically and in a cell-type-dependent manner in AD and PD brains. Moreover, using chemical perturbagen data, we computationally identified candidate small molecules for specifically targeting the profiled AD/PD-associated molecular alterations. Our approach therefore not only brings new insights into the disease-specific and common molecular etiologies of AD and PD but also, in these realms, foster the discovery of more specific targets for functional and therapeutic exploration.

A Possible Association Between Executive Dysfunction and Frailty in Patients With Neurocognitive Disorders

Frailty is an age-related dynamic status, characterized by a reduced resistance to stressors due to the cumulative decline of multiple physiological systems. Several researches have highlighted a relationship between physical frailty and cognitive decline; however, the role of specific cognitive domains has not been deeply clarified yet. Current studies have hypothesized that physical frailty and neuropsychological deficits may share systemic inflammation and increased oxidative stress in different neurodegenerative disorders, such as Alzheimer’s and Parkinson’s disease. However, the role of the executive dysfunction should be investigated in a more detailed way using a multidimensional approach. With this aim, we conducted a review of the literature on the few experimental articles published to discuss the existence of a relationship between frailty and cognitive impairment in neurocognitive disorders, particularly focusing on the domain of executive dysfunction. The data suggest that physical frailty and cognitive decline, especially executive dysfunction, are two aspects strongly linked in mild and major neurocognitive disorders due to Alzheimer’s and Parkinson’s disease. In light of this, a new framework linking aging, cognitive decline, and neurodegenerative diseases is needed. In order to analyze the effects that aging processes have on neural decline and neurocognitive disease, and to identify relevant groups of users and patients, future longitudinal studies should adopt a multidimensional approach, in the field of primary prevention and in the continuum from mild to major neurocognitive disorder.

Clustering of Alzheimer's and Parkinson's disease based on genetic burden of shared molecular mechanisms

One of the visions of precision medicine has been to re-define disease taxonomies based on molecular characteristics rather than on phenotypic evidence. However, achieving this goal is highly challenging, specifically in neurology. Our contribution is a machine-learning based joint molecular subtyping of Alzheimer's (AD) and Parkinson's Disease (PD), based on the genetic burden of 15 molecular mechanisms comprising 27 proteins (e.g. APOE) that have been described in both diseases. We demonstrate that our joint AD/PD clustering using a combination of sparse autoencoders and sparse non-negative matrix factorization is reproducible and can be associated with significant differences of AD and PD patient subgroups on a clinical, pathophysiological and molecular level. Hence, clusters are disease-associated. To our knowledge this work is the first demonstration of a mechanism based stratification in the field of neurodegenerative diseases. Overall, we thus see this work as an important step towards a molecular mechanism-based taxonomy of neurological disorders, which could help in developing better targeted therapies in the future by going beyond classical phenotype based disease definitions.

Miro (Mitochondrial Rho GTPase), a key player of mitochondrial axonal transport and mitochondrial dynamics in neurodegenerative diseases

Miro (mitochondrial Rho GTPases) a mitochondrial outer membrane protein, plays a vital role in the microtubule-based mitochondrial axonal transport, mitochondrial dynamics (fusion and fission) and Mito-Ca²⁺ homeostasis. It forms a major protein complex with Milton (an adaptor protein), kinesin and dynein (motor proteins), and facilitates bidirectional mitochondrial axonal transport such as anterograde and retrograde transport. By forming this protein complex, Miro facilitates the mitochondrial axonal transport and fulfills the neuronal energy demand, maintain the mitochondrial homeostasis and neuronal survival. It has been demonstrated that altered mitochondrial biogenesis, improper mitochondrial axonal transport, and mitochondrial dynamics are the early pathologies associated with most of the neurodegenerative diseases (NDs). Being the sole mitochondrial outer membrane protein associated with mitochondrial axonal transport-related processes, Miro proteins can be one of the key players in various NDs such as Alzheimer's disease (AD), Parkinson's disease (PD), Amyotrophic lateral sclerosis (ALS) and Huntington's disease (HD). Thus, in the current review, we have discussed the evolutionarily conserved Miro proteins and its role in the pathogenesis of the various NDs. From this, we indicated that Miro proteins may act as a potential target for a novel therapeutic intervention for the treatment of various NDs.

Network Simulations Reveal Molecular Signatures of Vulnerability to Age-Dependent Stress and Tau Accumulation

Alzheimer’s disease (AD) is the leading cause of dementia and one of the most common causes of death worldwide. As an age-dependent multifactorial disease, the causative triggers of AD are rooted in spontaneous declines in cellular function and metabolic capacity with increases in protein stressors such as the tau protein. This multitude of age-related processes that cause neurons to change from healthy states to ones vulnerable to the damage seen in AD are difficult to simultaneously investigate and even more difficult to quantify. Here we aimed to diminish these gaps in our understanding of neuronal vulnerability in AD development by using simulation methods to theoretically quantify an array of cellular stress responses and signaling molecules. This temporally-descriptive molecular signature was produced using a novel multimethod simulation approach pioneered by our laboratory for biological research; this methodology combines hierarchical agent-based processes and continuous equation-based modeling in the same interface, all while maintaining intrinsic distributions that emulate natural biological stochasticity. The molecular signature was validated for a normal organismal aging trajectory using experimental longitudinal data from Caenorhabditis elegans and rodent studies. In addition, we have further predicted this aging molecular signature for cells impacted by the pathogenic tau protein, giving rise to distinct stress response conditions needed for cytoprotective aging. Interestingly, our simulation experiments showed that oxidative stress signaling (via daf-16 and skn-1 activities) does not substantially protect cells from all the early stressors of aging, but that it is essential in preventing a late-life degenerative cellular phenotype. Together, our simulation experiments aid in elucidating neurodegenerative triggers in the onset of AD for different genetic conditions. The long-term goal of this work is to provide more detailed diagnostic and prognostic tools for AD development and progression, and to provide more comprehensive preventative measures for this disease.

Intra-gastrointestinal amyloid-β1-42 oligomers perturb enteric function and induce Alzheimer's disease pathology

KEY POINTS

Alzheimer's disease (AD) patients and transgenic mice have beta-amyloid (Aβ) aggregation in the gastrointestinal (GI) tract. It is possible that Aβ from the periphery contributes to the load of Aβ in the brain, as Aβ has prion-like properties. The present investigations demonstrate that Aβ injected into the GI tract of ICR mice is internalised into enteric cholinergic neurons; at 1 month, administration of Aβ into the body of the stomach and the proximal colon was observed to partly redistribute to the fundus and jejunum; at 1 year, vagal and cerebral β-amyloidosis was present, and mice exhibited GI dysfunction and cognitive deficits. These data reveal a previously undiscovered mechanism that potentially contributes to the development of AD.

ABSTRACT

Alzheimer's disease (AD) is the most common age-related cause of dementia, characterised by extracellular beta-amyloid (Aβ) plaques and intracellular phosphorylated tau tangles in the brain. Aβ deposits have also been observed in the gastrointestinal (GI) tract of AD patients and transgenic mice, with overexpression of amyloid precursor protein. In the present studies, we investigate whether intra-GI administration of Aβ can potentially induce amyloidosis in the central nervous system (CNS) and AD-related pathology such as dementia. We micro-injected Aβ1-42 oligomers (4 μg per site, five sites) or vehicle (saline, 5 μl) into the gastric wall of ICR mice under general anaesthesia. Immunofluorescence staining and in vivo imaging showed that HiLyte Fluor 555-labelled Aβ1-42 had migrated within 3 h via the submucosa to nearby areas and was internalised into cholinergic neurons. At 1 month, HiLyte Fluor 555-labelled Aβ1-42 in the body of the stomach and proximal colon had partly re-distributed to the fundus and jejunum. At 1 year, the jejunum showed functional alterations in neuromuscular coupling (P < 0.001), and Aβ deposits were present in the vagus and brain, with animals exhibiting cognitive impairments in the Y-maze spontaneous alteration test (P < 0.001) and the novel object recognition test (P < 0.001). We found that enteric Aβ oligomers induce an alteration in gastric function, amyloidosis in the CNS, and AD-like dementia via vagal mechanisms. Our results suggest that Aβ load is likely to occur initially in the GI tract and may translocate to the brain, opening the possibility of new strategies for the early diagnosis and prevention of AD.

Relationships between Mitochondrial Dysfunction and Neurotransmission Failure in Alzheimer's Disease

Besides extracellular deposition of amyloid beta and formation of phosphorylated tau in the brains of patients with Alzheimer's disease (AD), the pathogenesis of AD is also thought to involve mitochondrial dysfunctions and altered neurotransmission systems. However, none of these components can describe the diverse cognitive, behavioural, and psychiatric symptoms of AD without the pathologies interacting with one another. The purpose of this review is to understand the relationships between mitochondrial and neurotransmission dysfunctions in terms of (1) how mitochondrial alterations affect cholinergic and monoaminergic systems via disruption of energy metabolism, oxidative stress, and apoptosis; and (2) how different neurotransmission systems drive mitochondrial dysfunction via increasing amyloid beta internalisation, oxidative stress, disruption of mitochondrial permeabilisation, and mitochondrial trafficking. All these interactions are separately discussed in terms of neurotransmission systems. The association of mitochondrial dysfunctions with alterations in dopamine, norepinephrine, and histamine is the prospective goal in this research field. By unfolding the complex interactions surrounding mitochondrial dysfunction in AD, we can better develop potential treatments to delay, prevent, or cure this devastating disease.

Nanostructured Lipid Carriers Made of Ω-3 Polyunsaturated Fatty Acids: In Vitro Evaluation of Emerging Nanocarriers to Treat Neurodegenerative Diseases

Neurodegenerative diseases (ND) are one of the main problems of public health systems in the 21st century. The rise of nanotechnology-based drug delivery systems (DDS) has become in an emerging approach to target and treat these disorders related to the central nervous system (CNS). Among others, the use of nanostructured lipid carriers (NLCs) has increased in the last few years. Up to today, most of the developed NLCs have been made of a mixture of solid and liquid lipids without any active role in preventing or treating diseases. In this study, we successfully developed NLCs made of a functional lipid, such as the hydroxylated derivate of docohexaenoic acid (DHAH), named DHAH-NLCs. The newly developed nanocarriers were around 100 nm in size, with a polydispersity index (PDI) value of <0.3, and they exhibited positive zeta potential due to the successful chitosan (CS) and TAT coating. DHAH-NLCs were shown to be safe in both dopaminergic and microglia primary cell cultures. Moreover, they exhibited neuroprotective effects in dopaminergic neuron cell cultures after exposition to 6-hydroxydopamine hydrochloride (6-OHDA) neurotoxin and decreased the proinflammatory cytokine levels in microglia primary cell cultures after lipopolysaccharide (LPS) stimuli. The levels of the three tested cytokines, IL-6, IL-1β and TNF-α were decreased almost to control levels after the treatment with DHAH-NLCs. Taken together, these data suggest the suitability of DHAH-NLCs to attaining enhanced and synergistic effects for the treatment of NDs.

Noradrenaline protects neurons against H2 O2 -induced death by increasing the supply of glutathione from astrocytes via β3 -adrenoceptor stimulation

Oxidative stress has been implicated in a variety of neurodegenerative disorders, such as Alzheimer's and Parkinson's disease. Astrocytes play a significant role in maintaining survival of neurons by supplying antioxidants such as glutathione (GSH) to neurons. Recently, we found that noradrenaline increased the intracellular GSH concentration in astrocytes via β₃ -adrenoceptor stimulation. These observations suggest that noradrenaline protects neurons from oxidative stress-induced death by increasing the supply of GSH from astrocytes to neurons via the stimulation of β₃ -adrenoceptor in astrocytes. In the present study, we examined the protective effect of noradrenaline against H₂ O₂ -induced neurotoxicity using two different mixed cultures: the mixed culture of human astrocytoma U-251 MG cells and human neuroblastoma SH-SY5Y cells, and the mouse primary cerebrum mixed culture of neurons and astrocytes. H₂ O₂ -induced neuronal cell death was significantly attenuated by pretreatment with noradrenaline in both mixed cultures but not in single culture of SH-SY5Y cells or in mouse cerebrum neuron-rich culture. The neuroprotective effect of noradrenaline was inhibited by SR59230A, a selective β₃ -adrenoceptor antagonist, and CL316243, a selective β₃ -adrenoceptor agonist, mimicked the neuroprotective effect of noradrenaline. DL-buthionine-[S,R]-sulfoximine, a GSH synthesis inhibitor, negated the neuroprotective effect of noradrenaline in both mixed cultures. MK571, which inhibits the export of GSH from astrocytes mediated by multidrug resistance-associated protein 1, also prevented the neuroprotective effect of noradrenaline. These results suggest that noradrenaline protects neurons against H₂ O₂ -induced death by increasing the supply of GSH from astrocytes via β₃ -adrenoceptor stimulation.

Nanoparticle-Based Technology Approaches to the Management of Neurological Disorders

Neurological disorders are the most devastating and challenging diseases associated with the central nervous system (CNS). The blood-brain barrier (BBB) maintains homeostasis of the brain and contributes towards the maintenance of a very delicate microenvironment, impairing the transport of many therapeutics into the CNS and making the management of common neurological disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), cerebrovascular diseases (CVDs) and traumatic brain injury (TBI), exceptionally complicated. Nanoparticle (NP) technology offers a platform for the design of tissue-specific drug carrying systems owing to its versatile and modifiable nature. The prospect of being able to design NPs capable of successfully crossing the BBB, and maintaining a high drug bioavailability in neural parenchyma, has spurred much interest in the field of nanomedicine. NPs, which also come in an array of forms including polymeric NPs, solid lipid nanoparticles (SLNs), quantum dots and liposomes, have the flexibility of being conjugated with various macromolecules, such as surfactants to confer the physical or chemical property desired. These nanodelivery strategies represent potential novel and minimally invasive approaches to the treatment and diagnosis of these neurological disorders. Most of the strategies revolve around the ability of the NPs to cross the BBB via various influx mechanisms, such as adsorptive-mediated transcytosis (AMT) and receptor-mediated transcytosis (RMT), targeting specific biomarkers or lesions unique to that pathological condition, thereby ensuring high tissue-specific targeting and minimizing off-target side effects. In this article, insights into common neurological disorders and challenges of delivering CNS drugs due to the presence of BBB is provided, before an in-depth review of nanoparticle-based theranostic strategies.

Safety of Plasma Infusions in Parkinson's Disease

Background

Young plasma infusions have emerged as a potential treatment for neurodegenerative disease, and convalescent plasma therapy has been used safely in the management of viral pandemics. However, the effect of plasma therapy in Parkinson's disease (PD) is unknown.

Objectives

The objective of this study was to determine the safety, tolerability, and feasibility of plasma infusions in people with PD.

Methods

A total of 15 people with clinically established PD, at least 1 cognitive complaint, and on stable therapy received 1 unit of young fresh frozen plasma twice a week for 4 weeks. Assessments and adverse effects were performed/reported on and off therapy at baseline, immediately after, and 4 weeks after the infusions ended. Adverse effects were also assessed during infusions. The primary outcomes were safety, tolerability, and feasibility. Exploratory outcomes included Unified Parkinson's Disease Rating Scale Part III off medication, neuropsychological battery, Parkinson's Disease Questionnaire‐39, inflammatory markers (tumor necrosis factor‐α, interleukin‐6), uric acid, and quantitative kinematics.

Results

Adherence rate was 100% with no serious adverse effects. There was evidence of improvement in phonemic fluency (P = 0.002) and in the Parkinson's Disease Questionnaire‐39 stigma subscore (P = 0.013) that were maintained at the delayed evaluation. Elevated baseline tumor necrosis factor‐α levels decreased 4 weeks after the infusions ended.

Conclusions

Young fresh frozen plasma was safe, feasible, and well tolerated in people with PD, without serious adverse effects and with preliminary evidence for improvements in phonemic fluency and stigma. The results of this study warrant further therapeutic investigations in PD and provide safety and feasibility data for plasma therapy in people with PD who may be at higher risk for severe complications of COVID‐19. © 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Synaptic loss and amyloid beta alterations in the rodent hippocampus induced by streptozotocin injection into the cisterna magna

To date, researchers have developed various animal models of Alzheimer’s disease (AD) to investigate its mechanisms and to identify potential therapeutic treatments. A widely recognized model that mimics the pathology of human sporadic AD involves intracerebroventricular (ICV) injection with streptozotocin (STZ). However, ICV injections are an invasive approach, which creates limitations in generalizing the results. In this study, we produced a rodent model of AD using STZ (3 mg/kg) injection via the cisterna magna (CM) once every week for 4 weeks, and analyzed at 4 weeks and 16 weeks after final injection. In the CM-STZ rodent model of AD, we observed increase in extracellular amyloid-beta (Aβ) deposition and decrease and abnormal morphology of post-synaptic protein, PSD95 in 16 weeks STZ-injected group. The model developed using our less-invasive method induced features of AD-like pathology, including significantly increased extracellular amyloid-beta deposition, and decreased synaptic protein in the hippocampus. These findings supporting the success of this alternative approach, and thus, we suggest this is a promising, less invasive model for use in future AD research.

PhIP exposure in rodents produces neuropathology potentially relevant to Alzheimer's disease

Alzheimer's disease (AD) is a public health crisis due to debilitating cognitive symptoms and lack of curative treatments, in the context of increasing prevalence. Thus, it is critical to identify modifiable risk factors. High levels of meat consumption may increase AD risk. Many toxins are formed during meat cooking such as heterocyclic aromatic amines (HAAs). Our prior studies have shown that HAAs produce dopaminergic neurotoxicity. Given the mechanistic and pathological overlap between AD and dopaminergic disorders we investigated whether exposure to 2-amino-1-methyl-6-phenylimidazo [4,5-b] pyridine (PhIP), a prevalent dietary HAA formed during high-temperature meat cooking, may produce AD-relevant neurotoxicity. Here, C57BL/6 mice were treated with 100 or 200 mg/kg PhIP for 8 h or 75 mg/kg for 4 weeks and 16 weeks. PhIP exposure for 8 h produced oxidative damage, and AD-relevant alterations in hippocampal synaptic proteins, Amyloid-beta precursor protein (APP), and β-Site amyloid precursor protein cleaving enzyme 1 (BACE1). PhIP exposure for 4 weeks resulted in an increase in BACE1. PhIP exposure for 16 weeks resulted in increased hippocampal oxidative damage, APP, BACE1, Aβ aggregation, and tau phosphorylation. Quantification of intracellular nitrotyrosine revealed oxidative damage in cholinergic neurons after 8 h, 4 weeks and 16 weeks of PhIP exposure. Our study demonstrates that increase in oxidative damage, APP and BACE1 might be a possible mechanism by which PhIP promotes Aβ aggregation. Given many patients with AD or PD exhibit neuropathological overlap, our study suggests that HAA exposure should be further studied for roles in mediating pathogenic overlap.

T1-weighted MRI-driven Brain Age Estimation in Alzheimer's Disease and Parkinson's Disease

Neuroimaging-driven brain age estimation has introduced a robust (reliable and heritable) biomarker for detecting and monitoring neurodegenerative diseases. Here, we computed and compared brain age in Alzheimer's disease (AD) and Parkinson's disease (PD) patients using an advanced machine learning procedure involving T1-weighted MRI scans and gray matter (GM) and white matter (WM) models. Brain age estimation frameworks were built using 839 healthy individuals and then the brain estimated age difference (Brain-EAD: chronological age subtracted from brain estimated age) was assessed in a large sample of PD patients (n = 160) and AD patients (n = 129), respectively. The mean Brain-EADs for GM were +9.29 ± 6.43 years for AD patients versus +1.50 ± 6.03 years for PD patients. For WM, the mean Brain-EADs were +8.85 ± 6.62 years for AD patients versus +2.47 ± 5.85 years for PD patients. In addition, PD patients showed a significantly higher WM Brain-EAD than GM Brain-EAD. In a direct comparison between PD and AD patients, we observed significantly higher Brain-EAD values in AD patients for both GM and WM. A comparison of the Brain-EAD between PD and AD patients revealed that AD patients may have a significantly "older-appearing" brain than PD patients.

A Mouse Model of 1-Methyl-4-Phenyl-1,2,3,6-Tetrahydropyridine (MPTP)-Induced Parkinson Disease Shows that 2-Aminoquinoline Targets JNK Phosphorylation

BACKGROUND The pathological features of Parkinson disease (PD) include motor deficits, glial cell activation, and neuroinflammation. The neurotoxin, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), has an oxidation product, 1-methyl-4-phenylpyridinium ion (MPP+). This study aimed to investigate the effects of 2-aminoquinoline on motor deficits in a mouse model of MPTP-induced PD and cultured mouse astrocytes treated with MPP+, to determine the effects on astrocyte proliferation and apoptosis. MATERIAL AND METHODS Motor deficits in the mouse model of MPTP-induced PD were investigated using the climbing time, suspension time, and swim time tests. Cultured mouse astrocytes were treated with MPP+, and mice with MPTP-induced PD were treated with increasing doses of 2-aminoquinoline. The MTT assay was used to measure astrocyte viability. Astrocyte apoptosis was assessed by confocal fluorescence microscopy using Annexin‑V and fluorescein isothiocyanate (FITC) staining. Western blot measured the levels of Bax, p‑JNK, Bcl‑2, and caspase‑3. RESULTS In the mouse model of MPTP-induced PD, motor deficit tests showed that 2-aminoquinoline reduced the impaired motor function during the climbing time, the suspension time, and the swim time tests in a dose-dependent manner. Pre-treatment with 2-aminoquinoline significantly reduced the proliferation and apoptosis of astrocytes induced by MPP+ in vitro, in a dose-dependent manner (P<0.05). The levels of p‑JNK and cleaved caspase‑3 levels were significantly reduced in astrocytes treated with MPP+ following pre-treatment with 2-aminoquinoline, which also reversed the increase in the Bax/Bcl‑2 ratio. CONCLUSIONS In the mouse model of MPTP-induced PD, 2-aminoquinoline reduced motor deficiencies, inhibited MPP+ activated astrocyte apoptosis, and regulated the Bax/Bcl-2 ratio by targeting p-JNK.

Genetic networks in Parkinson's and Alzheimer's disease

Parkinson’s disease (PD) and Alzheimer’s disease (AD) are the most common neurodegenerative diseases and there is increasing evidence that they share common physiological and pathological links. Here we have conducted the largest network analysis of PD and AD based on their gene expressions in blood to date. We identified modules that were not preserved between disease and healthy control (HC) networks, and important hub genes and transcription factors (TFs) in these modules. We highlighted that the PD module not preserved in HCs was associated with insulin resistance, and HDAC6 was identified as a hub gene in this module which may have the role of influencing tau phosphorylation and autophagic flux in neurodegenerative disease. The AD module associated with regulation of lipolysis in adipocytes and neuroactive ligand-receptor interaction was not preserved in healthy and mild cognitive impairment networks and the key hubs TRPC5 and BRAP identified as potential targets for therapeutic treatments of AD. Our study demonstrated that PD and AD share common disrupted genetics and identified novel pathways, hub genes and TFs that may be new areas for mechanistic study and important targets in both diseases.

PET Radiopharmaceuticals for Alzheimer's Disease and Parkinson's Disease Diagnosis, the Current and Future Landscape

Ironically, population aging which is considered a public health success has been accompanied by a myriad of new health challenges, which include neurodegenerative disorders (NDDs), the incidence of which increases proportionally to age. Among them, Alzheimer's disease (AD) and Parkinson's disease (PD) are the most common, with the misfolding and the aggregation of proteins being common and causal in the pathogenesis of both diseases. AD is characterized by the presence of hyperphosphorylated τ protein (tau), which is the main component of neurofibrillary tangles (NFTs), and senile plaques the main component of which is β-amyloid peptide aggregates (Aβ). The neuropathological hallmark of PD is α-synuclein aggregates (α-syn), which are present as insoluble fibrils, the primary structural component of Lewy body (LB) and neurites (LN). An increasing number of non-invasive PET examinations have been used for AD, to monitor the pathological progress (hallmarks) of disease. Notwithstanding, still the need for the development of novel detection tools for other proteinopathies still remains. This review, although not exhaustively, looks at the timeline of the development of existing tracers used in the imaging of Aβ and important moments that led to the development of these tracers.

What and How Can Physical Activity Prevention Function on Parkinson's Disease?

Aim

This study was aimed at investigating the effects and molecular mechanisms of physical activity intervention on Parkinson's disease (PD) and providing theoretical guidance for the prevention and treatment of PD.

Methods

Four electronic databases up to December 2019 were searched (PubMed, Springer, Elsevier, and Wiley database), 176 articles were selected. Literature data were analyzed by the logic analysis method.

Results

(1) Risk factors of PD include dairy products, pesticides, traumatic brain injury, and obesity. Protective factors include alcohol, tobacco, coffee, black tea, and physical activity. (2) Physical activity can reduce the risk and improve symptoms of PD and the beneficial forms of physical activity, including running, dancing, traditional Chinese martial arts, yoga, and weight training. (3) Different forms of physical activity alleviate the symptoms of PD through different mechanisms, including reducing the accumulation of α-syn protein, inflammation, and oxidative stress, while enhancing BDNF activity, nerve regeneration, and mitochondrial function.

Conclusion

Physical activity has a positive impact on the prevention and treatment of PD. Illustrating the molecular mechanism of physical activity-induced protective effect on PD is an urgent need for improving the efficacy of PD therapy regimens in the future.

Neural Glyoxalase Pathway Enhancement by Morin Derivatives in an Alzheimer's Disease Model

The glyoxalase pathway (GP) is an antioxidant defense system that detoxifies metabolic byproduct methylglyoxal (MG). Through sequential reactions, reduced glutathione (GSH), glyoxalase I (glo-1), and glyoxalase II (glo-2) convert MG into d-lactate. Spontaneous reactions involving MG alter the structure and function of cellular macromolecules through the formation of inflammatory advanced glycation endproducts (AGEs). Accumulation of MG and AGEs in neural cells contributes to oxidative stress (OS), a state of elevated inflammation commonly found in neurodegenerative diseases including Alzheimer's disease (AD). Morin is a common plant-produced flavonoid polyphenol that exhibits the ability to enhance the GP-mediated detoxification of MG. We hypothesize that structural modifications to morin will improve its inherent GP enhancing ability. Here we synthesized a morin derivative, dibromo-morin (DBM), formulated a morin encapsulated nanoparticle (MNP), and examined their efficacy in enhancing neural GP activity. Cultured mouse primary cerebellar neurons and Caenorhabditis elegans were induced to a state of OS with MG and treated with morin, DBM, and MNP. Results indicated the morin derivatives were more effective compared to the parent compound in neural GP enhancement and preventing MG-mediated OS in an AD model.

Insights on the interaction of phenothiazinium dyes methylene blue and new methylene blue with synthetic duplex RNAs through spectroscopy and modeling

The ubiquitous influence of double stranded RNAs in biological events makes them imperative to gather data based on specific binding procedure of small molecules to various RNA conformations. Particular interest may be attributed to situations wherein small molecules target RNAs altering their structures and causing functional modifications. The main focus of this study is to delve into the interactive pattern of two small molecule phenothiazinium dyes, methylene blue and new methylene blue, with three duplex RNA polynucleotides-poly(A).poly(U), poly(C).poly(G) and poly(I).poly(C) by spectroscopic and molecular modeling techniques. Analysis of data as per Scatchard and Benesi-Hildebrand methodologies revealed highest affinity of these dyes to poly(A).poly(U) and least to poly(I).poly(C). In addition to fluorescence quenching, viscometric studies also substantiated that the dyes follow different modes of binding to different RNA polynucleotides. Distortion in the RNA structures with induced optical activity in the otherwise optically inactive dye molecules was evidenced from circular dichroism results. Dye-induced RNA structural modification occurred from extended conformation to compact particles visualized by atomic force microscopy. Molecular docking results revealed different binding patterns of the dye molecules within the RNA duplexes. The novelty of the present work lies towards a new contribution of the phenothiazinium dyes in dysfunctioning double stranded RNAs, advancing our knowledge to their potential use as RNA targeted small molecules.

Evaluation of the Common Molecular Basis in Alzheimer's and Parkinson's Diseases

Alzheimer's disease (AD) and Parkinson's disease (PD) are the most common neurodegenerative disorders related to aging. Though several risk factors are shared between these two diseases, the exact relationship between them is still unknown. In this paper, we analyzed how these two diseases relate to each other from the genomic, epigenomic, and transcriptomic viewpoints. Using an extensive literature mining, we first accumulated the list of genes from major genome-wide association (GWAS) studies. Based on these GWAS studies, we observed that only one gene (HLA-DRB5) was shared between AD and PD. A subsequent literature search identified a few other genes involved in these two diseases, among which SIRT1 seemed to be the most prominent one. While we listed all the miRNAs that have been previously reported for AD and PD separately, we found only 15 different miRNAs that were reported in both diseases. In order to get better insights, we predicted the gene co-expression network for both AD and PD using network analysis algorithms applied to two GEO datasets. The network analysis revealed six clusters of genes related to AD and four clusters of genes related to PD; however, there was very low functional similarity between these clusters, pointing to insignificant similarity between AD and PD even at the level of affected biological processes. Finally, we postulated the putative epigenetic regulator modules that are common to AD and PD.

Impact of CHRNA5 polymorphisms on the risk of schizophrenia in the Chinese Han population

BACKGROUND

Schizophrenia is a complex mental disease whose cause is still unknown. Neuronal nicotinic acetylcholine receptors (nAChRs) have been implicated in various neurological disorders, including schizophrenia. The previous reports have shown that CHRNA polymorphisms were involved in schizophrenia. This study is to explore the potential association between CHRNA5 (OMIM#118505) polymorphisms and schizophrenia susceptibility in a Chinese population.

METHODS AND RESULTS

A case-control study was conducted with 384 schizophrenia patients and 687 controls. We genotyped eight single nucleotide polymorphisms (SNPs) distributed in CHRNA5. Regulome DB, HaploReg, and GTEx databases were used to calculate possible functional effects of the polymorphisms. The χ² test, genetic model analysis, and haplotype analysis were involved in assessing genetic association between variants and schizophrenia risk. The results exhibited that rs17486278 (NC_000015.10:g.78575140A>C) was associated with a decreased risk of schizophrenia on the basis of the recessive model (adjusted OR = 0.37, 95%CI: 0.15-0.93) in females. Moreover, we found that the four variants rs588765, rs6495306, rs680244, rs692780 were extremely significant after being stratified by ≥45 years.

CONCLUSIONS

Overall, our findings supported that the potential association existed between CHRNA5 polymorphisms and schizophrenia susceptibility in a Chinese population. But, large sample validation is needed to enhance the accuracy of our results.

The value of cerebrospinal fluid α-synuclein and the tau/α-synuclein ratio for diagnosis of neurodegenerative disorders with Lewy pathology

BACKGROUND AND PURPOSE

Parkinson's disease (PD), dementia with Lewy bodies (DLB) and Alzheimer's disease (AD) are three of the most common neurodegenerative disorders. Up to 20% of these patients have the wrong diagnosis, due to overlapping symptoms and shared pathologies. A cerebrospinal fluid (CSF) biomarker panel for AD is making its way into the clinic, but an equivalent panel for PD and DLB and for improved differential diagnoses is still lacking. Using well-defined, community-based cohorts and validated analytical methods, the diagnostic value of CSF total-α-synuclein (t-α-syn) alone and in combination with total tau (t-tau) in newly diagnosed patients with PD, DLB and AD was determined.

METHODS

Cerebrospinal fluid concentrations of t-α-syn were assessed using our validated in-house enzyme-linked immunosorbent assay in 78 PD patients, 20 AD patients, 19 DLB patients and 32 controls. t-tau was measured using a commercial assay. Diagnostic performance was assessed by receiver operating characteristic curve analysis.

RESULTS

Compared to controls (mean 517 pg/ml), significantly lower levels of CSF t-α-syn in patients with PD (434 pg/ml, 16% reduction, P = 0.036), DLB (398 pg/ml, 23% reduction, P = 0.009) and AD (383 pg/ml, 26% reduction, P = 0.014) were found. t-α-syn levels did not differ significantly between PD, DLB and AD. The t-tau/t-α-syn ratio showed an improved performance compared to the single markers.

CONCLUSION

This is the first study to compare patients with PD, DLB and AD at the time of diagnosis. It was found that t-α-syn can contribute as a teammate with tau in a CSF biomarker panel for PD and DLB, and strengthen the existing biomarker panel for AD.

Repurposing of the β-Lactam Antibiotic, Ceftriaxone for Neurological Disorders: A Review

To date, there is no cure or disease-modifying agents available for most well-known neurological disorders. Current therapy is typically focused on relieving symptoms and supportive care in improving the quality of life of affected patients. Furthermore, the traditional de novo drug discovery technique is more challenging, particularly for neurological disorders. Therefore, the repurposing of existing drugs for these conditions is believed to be an efficient and dynamic approach that can substantially reduce the investments spent on drug development. Currently, there is emerging evidence that suggests the potential effect of a beta-lactam antibiotic, ceftriaxone (CEF), to alleviate the symptoms of different experimentally-induced neurological disorders: Parkinson's disease, Alzheimer's disease, amyotrophic lateral sclerosis, epileptic-seizure, brain ischemia, traumatic brain injuries, and neuropathic pain. CEF also affects the markers of oxidative status and neuroinflammation, glutamatergic systems as well as various aggregated toxic proteins involved in the pathogenesis of different neurological disorders. Moreover, it was found that CEF administration to drug dependent animal models improved the withdrawal symptoms upon drug discontinuation. Thus, this review aimed to describe the effects of CEF against multiple models of neurological illnesses, drug dependency, and withdrawal. It also emphasizes the possible mechanisms of neuroprotective actions of CEF with respective neurological maladies.

Gene expression meta-analysis of Parkinson's disease and its relationship with Alzheimer's disease

Parkinson’s disease (PD) and Alzheimer’s disease (AD) are the most common neurodegenerative diseases and have been suggested to share common pathological and physiological links. Understanding the cross-talk between them could reveal potentials for the development of new strategies for early diagnosis and therapeutic intervention thus improving the quality of life of those affected. Here we have conducted a novel meta-analysis to identify differentially expressed genes (DEGs) in PD microarray datasets comprising 69 PD and 57 control brain samples which is the biggest cohort for such studies to date. Using identified DEGs, we performed pathway, upstream and protein-protein interaction analysis. We identified 1046 DEGs, of which a majority (739/1046) were downregulated in PD. YWHAZ and other genes coding 14–3-3 proteins are identified as important DEGs in signaling pathways and in protein-protein interaction networks (PPIN). Perturbed pathways also include mitochondrial dysfunction and oxidative stress. There was a significant overlap in DEGs between PD and AD, and over 99% of these were differentially expressed in the same up or down direction across the diseases. REST was identified as an upstream regulator in both diseases. Our study demonstrates that PD and AD share significant common DEGs and pathways, and identifies novel genes, pathways and upstream regulators which may be important targets for therapy in both diseases.

Identification of Blood Biomarkers for Alzheimer's Disease Through Computational Prediction and Experimental Validation

Background: Alzheimer's disease (AD) is the major cause of dementia in population aged over 65 years, accounting up to 70% dementia cases. However, validated peripheral biomarkers for AD diagnosis are not available up to present. In this study, we adopted a new strategy of combination of computational prediction and experimental validation to identify blood protein biomarkers for AD.

Methods: First, we collected tissue-based gene expression data of AD patients and healthy controls from GEO database. Second, we analyzed these data and identified differentially expressed genes for AD. Third, we applied a blood-secretory protein prediction program on these genes and predicted AD-related proteins in blood. Finally, we collected blood samples of AD patients and healthy controls to validate the potential AD biomarkers by using ELISA experiments and Western blot analyses.

Results: A total of 2754 genes were identified to express differentially in brain tissues of AD, among which 296 genes were predicted to encode AD-related blood-secretory proteins. After careful analysis and literature survey on these predicted blood-secretory proteins, ten proteins were considered as potential AD biomarkers, five of which were experimentally verified with significant change in blood samples of AD vs. controls by ELISA, including GSN, BDNF, TIMP1, VLDLR, and APLP2. ROC analyses showed that VLDLR and TIMP1 had excellent performance in distinguishing AD patients from controls (area under the curve, AUC = 0.932 and 0.903, respectively). Further validation of VLDLR and TIMP1 by Western blot analyses has confirmed the results obtained in ELISA experiments.

Conclusion: VLDLR and TIMP1 had better discriminative abilities between ADs and controls, and might serve as potential blood biomarkers for AD. To our knowledge, this is the first time to identify blood protein biomarkers for AD through combination of computational prediction and experimental validation. In addition, VLDLR was first reported here as potential blood protein biomarker for AD. Thus, our findings might provide important information for AD diagnosis and therapies.

Endothelins in inflammatory neurological diseases

Endothelins were discovered more than thirty years ago as potent vasoactive compounds. Beyond their well-documented cardiovascular properties, however, the contributions of the endothelin pathway have been demonstrated in several neuroinflammatory processes and the peptides have been reported as clinically relevant biomarkers in neurodegenerative diseases. Several studies report that endothelin-1 significantly contributes to the progression of neuroinflammatory processes, particularly during infections in the central nervous system (CNS), and is associated with a loss of endothelial integrity at the blood brain barrier level. Because of the paucity of clinical trials with endothelin-1 antagonists in several infectious and non-infectious neuroinflammatory diseases, it remains an open question whether the 21 amino acid peptide is a mediator/modulator rather than a biomarker of the progression of neurodegeneration. This review focuses on the potential roles of endothelins in the pathology of neuroinflammatory processes, including infectious diseases of viral, bacterial or parasitic origin in which the synthesis of endothelins or its pharmacology have been investigated from the cell to the bedside in several cases, as well as in non-infectious inflammatory processes such as neurodegenerative disorders like Alzheimers Disease or central nervous system vasculitis.

Neuroprotection through flavonoid: Enhancement of the glyoxalase pathway

The glyoxalase pathway functions to detoxify reactive dicarbonyl compounds, most importantly methylglyoxal. The glyoxalase pathway is an antioxidant defense mechanism that is essential for neuroprotection. Excessive concentrations of methylglyoxal have deleterious effects on cells, leading to increased levels of inflammation and oxidative stress. Neurodegenerative diseases - including Alzheimer's, Parkinson's, Aging and Autism Spectrum Disorder - are often induced or exacerbated by accumulation of methylglyoxal. Antioxidant compounds possess several distinct mechanisms that enhance the glyoxalase pathway and function as neuroprotectants. Flavonoids are well-researched secondary plant metabolites that appear to be effective in reducing levels of oxidative stress and inflammation in neural cells. Novel flavonoids could be designed, synthesized and tested to protect against neurodegenerative diseases through regulating the glyoxalase pathway.

Proteomics Analysis of Blood Serums from Alzheimer's Disease Patients Using iTRAQ Labeling Technology

Alzheimer' disease (AD) is the most common form of dementia affecting up to 6% of the population over the age of 65. In order to discover differentially expressed proteins that might serve as potential biomarkers, the serums from AD patients and healthy controls were compared and analyzed using the proteomics approach of isobaric tagging for relative and absolute quantitation (iTRAQ). For the first time, AD biomarkers in serums are investigated in the Han Chinese population using iTRAQ labeled proteomics strategy. Twenty-two differentially expressed proteins were identified and out of which nine proteins were further validated with more sample test. Another three proteins that have been reported in the literature to be potentially associated with AD were also investigated for alteration in expression level. Functions of those proteins were mainly related to the following processes: amyloid-β (Aβ) metabolism, cholesterol transport, complement and coagulation cascades, immune response, inflammation, hemostasis, hyaluronan metabolism, and oxidative stress. These results support current views on the molecular mechanism of AD. For the first time, differential expression of zinc-alpha-2-glycoprotein (AZGP1), fibulin-1 (FBLN1), platelet basic protein (PPBP), thrombospondin-1 (THBS1), S100 calcium-binding protein A8 (S100A8), and S100 calcium-binding protein A9 (S100A9) were detected in the serums of AD patients compared with healthy controls. These proteins might play a role in AD pathophysiology and serve as potential biomarkers for AD diagnosis. Specifically, our results strengthened the crucial role of Aβ metabolism and blood coagulation in AD pathogenesis and proteins related to these two processes may be used as peripheral blood biomarkers for AD.

Understanding Miro GTPases: Implications in the Treatment of Neurodegenerative Disorders

The Miro GTPases represent an unusual subgroup of the Ras superfamily and have recently emerged as important mediators of mitochondrial dynamics and for maintaining neuronal health. It is now well-established that these enzymes act as essential components of a Ca²⁺-sensitive motor complex, facilitating the transport of mitochondria along microtubules in several cell types, including dopaminergic neurons. The Miros appear to be critical for both anterograde and retrograde mitochondrial transport in axons and dendrites, both of which are considered essential for neuronal health. Furthermore, the Miros may be significantly involved in the development of several serious pathological processes, including the development of neurodegenerative and psychiatric disorders. In this review, we discuss the molecular structure and known mitochondrial functions of the Miro GTPases in humans and other organisms, in the context of neurodegenerative disease. Finally, we consider the potential human Miros hold as novel therapeutic targets for the treatment of such disease.

Association of IGF1 gene polymorphism with Parkinson's disease in a Han Chinese population

BACKGROUND

Accumulating evidence suggests that insulin-like growth factor 1 (IGF1) plays an important role in Parkinson's disease (PD) pathogenesis. However, it is not clear whether IGF1 polymorphism contributes to PD risk.

METHODS

We performed a case-control study in a Han Chinese population that included 512 sporadic PD cases and 535 matched controls. All participants were genotyped for rs972936 using the Sequenom MassARRAY iPLEX platform. Serum IGF1 levels of 61 de novo, drug-naïve PD patients and 55 age- and sex-matched controls were also measured using an enzyme-linked immunosorbent assay.

RESULTS

Genotype frequency of rs972936-CC was significantly associated with an increased PD risk (p = 0.009), especially in males (p = 0.024) and late-onset patients (p = 0.013). Serum IGF1 levels were significantly increased in de novo, drug-naïve PD patients compared to controls (p = 0.036), although they were not correlated with motor dysfunction in PD patients (p = 0.220).

CONCLUSIONS

The present study shows that rs972936 polymorphism may increase susceptibility to PD, especially in males and late-onset patients. Furthermore, high serum IGF1 levels may be a potential diagnostic biomarker for PD in the Han Chinese population, although they do not correlate with a more severe motor dysfunction.

Subcellular analysis of pigeon hair cells implicates vesicular trafficking in cuticulosome formation and maintenance

Hair cells are specialized sensors located in the inner ear that enable the transduction of sound, motion, and gravity into neuronal impulses. In birds some hair cells contain an iron-rich organelle, the cuticulosome, that has been implicated in the magnetic sense. Here, we exploit histological, transcriptomic, and tomographic methods to investigate the development of cuticulosomes, as well as the molecular and subcellular architecture of cuticulosome positive hair cells. We show that this organelle forms rapidly after hatching in a process that involves vesicle fusion and nucleation of ferritin nanoparticles. We further report that transcripts involved in endocytosis, extracellular exosomes, and metal ion binding are differentially expressed in cuticulosome positive hair cells. These data suggest that the cuticulosome and the associated molecular machinery regulate the concentration of iron within the labyrinth of the inner ear, which might indirectly tune a magnetic sensor that relies on electromagnetic induction.

Experimental oral iron administration: Histological investigations and expressions of iron handling proteins in rat retina with aging

Iron is implicated in age-related macular degeneration (AMD). The aim of this study was to see if long-term, experimental iron administration with aging modifies retinal and choroidal structures and expressions of iron handling proteins, to understand some aspects of iron homeostasis. Male Wistar rats were fed with ferrous sulphate heptahydrate (500mg/kg body weight/week, oral; elemental iron availability: 20%) from 2 months of age onward until they were 19.5 month-old. At 8, 14 and 20 months of age, they were sacrificed and serum and retinal iron levels were detected by HPLC. Oxidative stress was analyzed by TBARS method. The retinas were examined for cell death (TUNEL), histology (electron microscopy) and the expressions of transferrin, transferrin receptor-1 [TFR-1], H- and L-ferritin. In control animals, at any age, there was no difference in the serum and retinal iron levels, but the latter increased significantly in 14- and 20 month-old iron-fed rats, indicating that retinal iron accumulation proceeds with progression of aging (>14 months). The serum and retinal TBARS levels increased significantly with progression of aging in experimental but not in control rats. There was significant damage to choriocapillaris, accumulation of phagosomes in retinal pigment epithelium and increased incidence of TUNEL+ cells in outer nuclear layer and vacuolation in inner nuclear layer (INL) of 20 month-aged experimental rats, compared to those in age-matched controls. Vacuolations in INL could indicate a long-term effect of iron accumulation in the inner retina. These events paralleled the increased expression of ferritins and transferrin and a decrease in the expression of TFR-1 in iron-fed rats with aging, thereby maintaining iron homeostasis in the retina. As some of these changes mimic with those happening in eyes with AMD, this model can be utilized to understand iron-induced pathophysiological changes in AMD.

Neuroprotective effects of astragaloside IV on Parkinson disease models of mice and primary astrocytes

Parkinson's disease (PD) is characterized by a progressive degeneration of dopaminergic neurons in the substantia nigra pars compacta. Inflammation and neural degeneration are implicated in the pathogenesis of PD. Astragaloside IV (AS-IV) has been verified to attenuate inflammation. The current study aimed to investigate the role of AS-IV in PD and the possible molecular mechanisms. Pole, traction and swim tests were performed to examine the effects of AS-IV on 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP)-generated behavioral deficiencies in vivo. Meanwhile, as for in vitro experiments, the influence of AS-IV on cell viability was evaluated using the 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) assay, the effects of AS-IV on 1-methyl-4-phenylpyridnium ion (MPP+)-induced cell viability changes were tested using MTT assays, cell apoptosis rates were assessed using an Annexin-V Fluorescein isothiocyanate kit, and the expression levels of phosphorylated-Jun N-terminal kinase (p-JNK), Bcl-2-associated X protein (Bax)/Bcl-2 and caspase-3 activity were assessed using western blot analysis. Behavioral tests showed that pretreatment of AS-IV significantly alleviated MPTP-generated behavioral deficiencies in vivo. Meanwhile, AS-IV remarkably rescued MPP+-induced cell viability reduction, increase in cell apoptosis rate, and upregulation of p-JNK, Bax/Bcl-2 ratio and caspase-3 activity in vitro. In conclusion, AS-IV may be a promising neuroprotective agent for PD.

Neuro-protective effect of rutin against Cisplatin-induced neurotoxic rat model

Background

Cisplatin is widely used chemotherapeutic agent for cancer treatment with limited uses due to its neurotoxic side effect. The aim of this study was to determine the potential preventive effects of rutin on the brain of cisplatin- neurotoxic rat model.

Methods

Forty rats were divided into four groups. Group-1 (control group) was intra-peritoneal (IP) injected with 2.5 ml/kg saline. Group-2 (rutin group) was orally administrated 30 mg/kg rutin dissolved in water for 14 days. Group-3 (cisplatin group) was IP received 5 mg/kg cisplatin single dose. Group-4 (rutin and cisplatin group) was orally administrated 30 mg/kg rutin dissolved in water for 14 days with a single dose of 5 mg/kg cisplatin IP on day ten. Brain tissues from frontal cortex was used to extract RNA, the gene expression levels of paraoxonase-1 (PON-1), PON-2, PON-3, peroxisome proliferator-activated receptor delta (PPAR-δ), and glutathione peroxidase (GPx) was investigated by Real-time PCR.

Results

Cisplatin significantly decreased the expression levels of PON-1, PON-3, PPAR-δ and GPX whereas significantly increased PON-2 expression levels. Co-administration of Rutin prevented the cisplatin-induced toxicity by restoring the alteration in the studied genes to normal values as in the control group.

Conclusion

This study showed that Rutin has neuroprotective effect and reduces cisplatin- neurotoxicity with possible mechanism via the antioxidant pathway.