Neurodegenerative Diseases: Regenerative Mechanisms and Novel Therapeutic Approaches

Endocannabinoid Modulation in Neurodegenerative Diseases: In Pursuit of Certainty

Simple Summary

Neurodegenerative diseases represent an important cause of morbidity and mortality worldwide. Existing therapeutic options are limited and focus mostly on improving symptoms and reducing exacerbations. The endocannabinoid system is involved in the pathophysiology of such disorders, an idea which has been highlighted by recent scientific work. The current work focusses its attention on the importance and implications of this system and its synthetic and natural ligands in disorders such as Alzheimer’s, Parkinson’s, Huntington’s and multiple sclerosis.

Abstract

Neurodegenerative diseases are an increasing cause of global morbidity and mortality. They occur in the central nervous system (CNS) and lead to functional and mental impairment due to loss of neurons. Recent evidence highlights the link between neurodegenerative and inflammatory diseases of the CNS. These are typically associated with several neurological disorders. These diseases have fundamental differences regarding their underlying physiology and clinical manifestations, although there are aspects that overlap. The endocannabinoid system (ECS) is comprised of receptors (type-1 (CB1R) and type-2 (CB2R) cannabinoid-receptors, as well as transient receptor potential vanilloid 1 (TRPV1)), endogenous ligands and enzymes that synthesize and degrade endocannabinoids (ECBs). Recent studies revealed the involvement of the ECS in different pathological aspects of these neurodegenerative disorders. The present review will explore the roles of cannabinoid receptors (CBRs) and pharmacological agents that modulate CBRs or ECS activity with reference to Alzheimer’s Disease (AD), Parkinson’s Disease (PD), Huntington’s Disease (HD) and multiple sclerosis (MS).

Mammalian target of rapamycin (mTOR) signaling pathway and traumatic brain injury: A novel insight into targeted therapy

Traumatic brain injury (TBI) is one of the most concerning health issues in which the normal brain function may be disrupted as a result of a blow, bump, or jolt to the head. Loss of consciousness, amnesia, focal neurological defects, alteration in mental state, and destructive diseases of the nervous system such as cognitive impairment, Parkinson's, and Alzheimer's disease. Parkinson's disease is a chronic progressive neurodegenerative disorder, characterized by the early loss of striatal dopaminergic neurons. TBI is a major risk factor for Parkinson's disease. Existing therapeutic approaches have not been often effective, indicating the necessity of discovering more efficient therapeutic targets. The mammalian target of rapamycin (mTOR) signaling pathway responds to different environmental cues to modulate a large number of cellular processes such as cell proliferation, survival, protein synthesis, autophagy, and cell metabolism. Moreover, mTOR has been reported to affect the regeneration of the injured nerves throughout the central nervous system (CNS). In this context, recent evaluations have revealed that mTOR inhibitors could be potential targets to defeat a group of neurological disorders, and thus, a number of clinical trials are investigating their efficacy in treating dementia, autism, epilepsy, stroke, and brain injury, as irritating neurological defects. The current review describes the interplay between mTOR signaling and major CNS-related disorders (esp. neurodegenerative diseases), as well as the mTOR signaling-TBI relationship. It also aims to discuss the promising therapeutic capacities of mTOR inhibitors during the TBI.

Investigating Casual Associations Among Gut Microbiota, Metabolites, and Neurodegenerative Diseases: A Mendelian Randomization Study

BACKGROUND

Recent studies had explored that gut microbiota was associated with neurodegenerative diseases (including Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS)) through the gut-brain axis, among which metabolic pathways played an important role. However, the underlying causality remained unclear.

OBJECTIVE

Our study aimed to evaluate potential causal relationships between gut microbiota, metabolites, and neurodegenerative diseases through Mendelian randomization (MR) approach.

METHODS

We selected genetic variants associated with gut microbiota traits (N = 18,340) and gut microbiota-derived metabolites (N = 7,824) from genome-wide association studies. Summary statistics of neurodegenerative diseases were obtained from IGAP (AD, 17,008 cases; 37,154 controls), IPDGC (PD, 37,688 cases; 141,779 controls), and IALSC (ALS, 20,806 cases; 59,804 controls) respectively.

RESULTS

Greater abundance of Ruminococcus (OR, 1.245; 95% CI, 1.103-1.405; p = 0.0004) was found significantly related to higher risk of ALS. Besides, our study found suggestive associations of Actinobacteria, Lactobacillaceae, Faecalibacterium, Ruminiclostridium, and Lachnoclostridium with AD, of Lentisphaerae, Lentisphaeria, Oxalobacteraceae, Victivallales, Bacillales, Eubacteriumhalliigroup, Anaerostipes, and Clostridiumsensustricto1 with PD, and of Lachnospira, Fusicatenibacter, Catenibacterium, and Ruminococcusgnavusgroup with ALS. Our study also revealed suggestive associations between 12 gut microbiome-dependent metabolites and neurodegenerative diseases. Glutamine was related to lower risk of AD. For the serotonin pathway, serotonin was found as a protective factor of PD, while kynurenine as a risk factor for ALS.

CONCLUSION

Our study firstly applied a two-sample MR approach to detect causal relationships among gut microbiota, gut metabolites, and neurodegenerative diseases. Our findings may provide new targets for treatments and may offer valuable insights for further studies on the underlying mechanisms.

A review of dementia, focusing on the distinct roles of viral protein corona and MMP9 in dementia: Potential pharmacotherapeutic priorities

Dementia, in particular, is a defining feature of Alzheimer's and Parkinson's diseases. Because of the combination of motor and cognitive impairments, Parkinson's disease dementia (PDD) has a greater impact on affected people than Alzheimer's disease dementia (ADD) and others. If one family member develops dementia, the other members will suffer greatly in terms of social and occupational functioning. Currently, no relevant treatment is available based on an examination of the absolute pathophysiology of dementia. As a result, our objective of current review encouraged to look for dementia pharmacotherapy based on their pathogenesis. We systematically searched electronic databases such as PubMed, Scopus, and ESCI for information on the pathophysiology of demetia, as well as their treatment with allopathic and herbal medications. By modulating intermediate proteins, oxidative stress, viral protein corona, and MMP9 are etiological factors that cause dementia. The pathophysiology of ADD was described by two hypotheses: the amyloid cascade hypothesis and the tau and tangle hypothesis. ADD is caused by an increase in amyloid-beta (Aβ) and neurofibrillary tangles in the cerebrum. The viral protein corona (VPC) is more contagious and helps to form amyloid-beta (Aβ) plaques and neurofibrillary tangles in the cerebrum. Thioredoxin interacting protein (TXNIP) inside the BBB encourages Aβ to become more engaged. PDD is caused by decreased or absent dopamine secretion from nerve cells in the substantia nigra, as well as PRKN gene deletion/duplication mutations, and shift in the PRKN-PACRG organisation, all of which are linked to ageing. This article discussed the pathophysiology of dementia, as well as a list of herbal medications that can easily cross the BBB and have a therapeutic effect on dementia.

Therapeutic Efficacies of Berberine against Neurological Disorders: An Update of Pharmacological Effects and Mechanisms

Neurological disorders are ranked as the leading cause of disability and the second leading cause of death worldwide, underscoring an urgent necessity to develop novel pharmacotherapies. Berberine (BBR) is a well-known phytochemical isolated from a number of medicinal herbs. BBR has attracted much interest for its broad range of pharmacological actions in treating and/or managing neurological disorders. The discoveries in basic and clinical studies of the effects of BBR on neurological disorders in the last decade have provided novel evidence to support the potential therapeutical efficacies of BBR in treating neurological diseases. In this review, we summarized the pharmacological properties and therapeutic applications of BBR against neurological disorders in the last decade. We also emphasized the major pathways modulated by BBR, which provides firm evidence for BBR as a promising drug candidate for neurological disorders.

Molecular Mechanisms and Therapeutic Potential of α- and β-Asarone in the Treatment of Neurological Disorders

Neurological disorders are important causes of morbidity and mortality around the world. The increasing prevalence of neurological disorders, associated with an aging population, has intensified the societal burden associated with these diseases, for which no effective treatment strategies currently exist. Therefore, the identification and development of novel therapeutic approaches, able to halt or reverse neuronal loss by targeting the underlying causal factors that lead to neurodegeneration and neuronal cell death, are urgently necessary. Plants and other natural products have been explored as sources of safe, naturally occurring secondary metabolites with potential neuroprotective properties. The secondary metabolites α- and β-asarone can be found in high levels in the rhizomes of the medicinal plant Acorus calamus (L.). α- and β-asarone exhibit multiple pharmacological properties including antioxidant, anti-inflammatory, antiapoptotic, anticancer, and neuroprotective effects. This paper aims to provide an overview of the current research on the therapeutic potential of α- and β-asarone in the treatment of neurological disorders, particularly neurodegenerative diseases such as Alzheimer’s disease (AD), Parkinson’s disease (PD), as well as cerebral ischemic disease, and epilepsy. Current research indicates that α- and β-asarone exert neuroprotective effects by mitigating oxidative stress, abnormal protein accumulation, neuroinflammation, neurotrophic factor deficit, and promoting neuronal cell survival, as well as activating various neuroprotective signalling pathways. Although the beneficial effects exerted by α- and β-asarone have been demonstrated through in vitro and in vivo animal studies, additional research is required to translate laboratory results into safe and effective therapies for patients with AD, PD, and other neurological and neurodegenerative diseases.

Acute Oral, Subacute, and Developmental Toxicity Profiling of Naphthalene 2-Yl, 2-Chloro, 5-Nitrobenzoate: Assessment Based on Stress Response, Toxicity, and Adverse Outcome Pathways

The U.S. National Research Council (NRC) introduced new approaches to report toxicity studies. The NRC vision is to explore the toxicity pathways leading to the adverse effects in intact organisms by the exposure of the chemicals. This study examines the toxicity profiling of the naphthalene-2-yl 2-chloro-5-dinitrobenzoate (SF5) by adopting the vision of NRC that moves from traditional animal studies to the cellular pathways. Acute, subacute, and developmental toxicity studies were assayed according to the Organization for Economic Cooperation and Development (OECD) guidelines. The stress response pathway, toxicity pathway, and adverse effects outcome parameters were analyzed by using their standard protocols. The results showed that the acute toxicity study increases the liver enzyme levels. In a subacute toxicity study, alkaline phosphatase (ALP) levels were raised in both male and female animals. SF5 significantly increases the normal sperm count in the male animals corresponding to a decrease in the abnormality count. Developmental toxicity showed the normal skeletal and morphological parameters, except little hydrocephalus was observed in developmental toxicity. Doses of 20 mg/kg in males and 4 mg/kg in females showed decreased glutathione (GSH) levels in the kidney and liver. MDA levels were also increased in the kidney and liver. However, histopathological studies did not show any cellular change in these organs. No statistical difference was observed in histamine levels, testosterone, nuclear factor erythroid two-related factor-2 (Nrf2), and nuclear factor-kappa B (NF-κB), which showed no initiation of the stress response, toxicity, and adverse effect pathways. Immunomodulation was observed at low doses in subacute toxicity studies. It was concluded that SF5 did not produce abrupt and high-toxicity levels in organs and biochemical parameters. So, it is safe for further studies.

Therapeutic Potential of Vital Transcription Factors in Alzheimer's and Parkinson's Disease With Particular Emphasis on Transcription Factor EB Mediated Autophagy

Autophagy is an important cellular self-digestion and recycling pathway that helps in maintaining cellular homeostasis. Dysregulation at various steps of the autophagic and endolysosomal pathway has been reported in several neurodegenerative disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington disease (HD) and is cited as a critically important feature for central nervous system (CNS) proteostasis. Recently, another molecular target, namely transcription factor EB (TFEB) has been explored globally to treat neurodegenerative disorders. This TFEB, is a key regulator of autophagy and lysosomal biogenesis pathway. Multiple research studies suggested therapeutic potential by targeting TFEB to treat human diseases involving autophagy-lysosomal dysfunction, especially neurodegenerative disorders. A common observation involving all neurodegenerative disorders is their poor efficacy in clearing and recycle toxic aggregated proteins and damaged cellular organelles due to impairment in the autophagy pathway. This dysfunction in autophagy characterized by the accumulation of toxic protein aggregates leads to a progressive loss in structural integrity/functionality of neurons and may even result in neuronal death. In recent years TFEB, a key regulator of autophagy and lysosomal biogenesis, has received considerable attention. It has emerged as a potential therapeutic target in numerous neurodegenerative disorders like AD and PD. In various neurobiology studies involving animal models, TFEB has been found to ameliorate neurotoxicity and rescue neurodegeneration. Since TFEB is a master transcriptional regulator of autophagy and lysosomal biogenesis pathway and plays a crucial role in defining autophagy activation. Studies have been done to understand the mechanisms for TFEB dysfunction, which may yield insights into how TFEB might be targeted and used for the therapeutic strategy to develop a treatment process with extensive application to neurodegenerative disorders. In this review, we explore the role of different transcription factor-based targeted therapy by some natural compounds for AD and PD with special emphasis on TFEB.

The Influence of Seasonality on Secondary Metabolite Profiles and Neuroprotective Activities of Moss Hypnum cupressiforme Extracts: In Vitro and In Silico Study

Numerous representatives of mosses, including Hypnum cupressiforme, have been used to alleviate different inflammation-related conditions. However, the mode of action underlying this anti-inflammatory potential has been poorly understood. Moreover, the influence of seasonality on the chemical composition and biological activity of mosses is generally overlooked. This study aimed to investigate the influence of seasonal changes (spring, summer, and autumn) on secondary metabolite composition and biological activities of ethyl acetate H. cupressiforme extracts. Antioxidant activity was measured using β-carotene bleaching assay, while MTT, NBT, ELISA, and Griess assays were carried out to explore the anti-neuroinflammatory and neuroprotective potential of extracts. Inhibitory activities on acetylcholinesterase and tyrosinase were assessed experimentally and by docking analysis. The highest content of secondary metabolites and antioxidant activity were observed in moss during the summer. Extracts inhibited the secretion of ROS, NO, TNF-α, and IL-6, alleviating the inflammatory potential of H₂O₂ and LPS in microglial and neuronal cells. Strong inhibitory effects on acetylcholinesterase and tyrosinase were observed in vitro. Docking analyses revealed high-affinity interactions of secondary metabolites present in H. cupressiforme with important enzyme residues. Altogether, these results reveal the neuroprotective potential and the significance of seasonal fluctuations on secondary metabolite content and biological activities in moss H. cupressiforme.

Transcriptional Analysis of Nuclear-Encoded Mitochondrial Genes in Eight Neurodegenerative Disorders: The Analysis of Seven Diseases in Reference to Friedreich’s Ataxia

Neurodegenerative diseases (NDDs) are challenging to understand, diagnose, and treat. Revealing the genomic and transcriptomic changes in NDDs contributes greatly to the understanding of the diseases, their causes, and development. Moreover, it enables more precise genetic diagnosis and novel drug target identification that could potentially treat the diseases or at least ease the symptoms. In this study, we analyzed the transcriptional changes of nuclear-encoded mitochondrial (NEM) genes in eight NDDs to specifically address the association of these genes with the diseases. Previous studies show strong links between defects in NEM genes and neurodegeneration, yet connecting specific genes with NDDs is not well studied. Friedreich’s ataxia (FRDA) is an NDD that cannot be treated effectively; therefore, we focused first on FRDA and compared the outcome with seven other NDDs, including Alzheimer’s disease, amyotrophic lateral sclerosis, Creutzfeldt–Jakob disease, frontotemporal dementia, Huntington’s disease, multiple sclerosis, and Parkinson’s disease. First, weighted correlation network analysis was performed on an FRDA RNA-Seq data set, focusing only on NEM genes. We then carried out differential gene expression analysis and pathway enrichment analysis to pinpoint differentially expressed genes that are potentially associated with one or more of the analyzed NDDs. Our findings propose a strong link between NEM genes and NDDs and suggest that our identified candidate genes can be potentially used as diagnostic markers and therapeutic targets.

Emerging nanoformulation strategies for phytocompounds and applications from drug delivery to phototherapy to imaging

Over thousands of years, natural bioactive compounds derived from plants (bioactive phytocompounds, BPCs) have been used worldwide to address human health issues. Today, they are a significant resource for drug discovery in the development of modern medicines. Although many BPCs have promising biological activities, most of them cannot be effectively utilized in drugs for therapeutic applications because of their inherent limitations of low solubility, structural instability, short half-life, poor bioavailability, and non-specific distribution to organs. Researchers have utilized emerging nanoformulation (NF) technologies to overcome these limitations as they have demonstrated great potential to improve the solubility, stability, and pharmacokinetic and pharmacodynamic characteristics of BPCs. This review exemplifies NF strategies for resolving the issues associated with BPCs and summarizes recent advances in their preclinical and clinical applications for imaging and therapy. This review also highlights how innovative NF technologies play a leading role in next-generation BPC-based drug development for extended therapeutic applications. Finally, this review discusses the opportunities to take BPCs with meaningful clinical impact from bench to bedside and extend the patent life of BPC-based medicines with new formulations or application to new adjacent diseases beyond the primary drug indications.

•

Natural bioactive phytocompounds derived from plants have been used worldwide to address human health issues. However, most of them cannot be effectively utilized in drugs for therapeutic applications because of their inherent limitations.

•

Nanoformulation approach has recently been underlined as an emerging pharmaceutical strategy to overcome the intrinsic drawbacks of bioactive phytocompounds.

•

Various types of nanoformulation and their up-to-date applications for targeted delivery, phototherapy, and imaging are reviewed. Finally, their clinical implications for the repurposing of bioactive phytocompounds are deliberated.

The neurobiology of non-coding RNAs and Alzheimer's disease pathogenesis: Pathways, mechanisms and translational opportunities

In the past two decades, advances in sequencing technology and analysis of the human and mouse genome have led to the discovery of many non-protein-coding RNAs (ncRNAs) including: microRNA, small-interfering RNAs, piwi-associated small RNAs, transfer RNA-derived small RNAs, long-non-coding RNAs and circular RNAs. Compared with healthy controls, levels of some ncRNAs are significantly altered in the central nervous system and blood of patients affected by neurodegenerative disorders like Alzheimer's disease (AD). Although the mechanisms are still not fully elucidated, studies have revealed that these highly conserved ncRNAs are important modulators of gene expression, amyloid-β production, tau phosphorylation, inflammation, synaptic plasticity and neuronal survival, all features considered central to AD pathogenesis. Despite considerable difficulties due to their large heterogeneity, and the complexity of their regulatory pathways, research in this rapidly growing field suggests that ncRNAs hold great potential as biomarkers and therapeutic targets against AD. Herein, we summarize the current knowledge regarding the neurobiology of ncRNA in the context of AD pathophysiology.

Optimized Rivastigmine Nanoparticles Coated with Eudragit for Intranasal Application to Brain Delivery: Evaluation and Nasal Ciliotoxicity Studies

Rivastigmine, a reversible cholinesterase inhibitor, is frequently indicated in the management of demented conditions associated with Alzheimer disease. The major hurdle of delivering this drug through the oral route is its poor bioavailability, which prompted the development of novel delivery approaches for improved efficacy. Due to numerous beneficial properties associated with nanocarriers in the drug delivery system, rivastigmine nanoparticles were fabricated to be administer through the intranasal route. During the development of the nanoparticles, preliminary optimization of processing and formulation parameters was done by the design of an experimental approach. The drug-polymer ratio, stirrer speed, and crosslinking time were fixed as independent variables, to analyze the effect on the entrapment efficiency (% EE) and in vitro drug release of the drug. The formulation (D8) obtained from 2³ full factorial designs was further coated using Eudragit EPO to extend the release pattern of the entrapped drug. Furthermore, the 1:1 ratio of core to polymer depicted spherical particle size of ~175 nm, % EE of 64.83%, 97.59% cumulative drug release, and higher flux (40.39 ± 3.52 µg.h/cm²). Finally, the intranasal ciliotoxicity study on sheep nasal mucosa revealed that the exposure of developed nanoparticles was similar to the negative control group, while destruction of normal architecture was noticed in the positive control test group. Overall, from the in vitro results it could be summarized that the optimization of nanoparticles' formulation of rivastigmine for intranasal application would be retained at the application site for a prolonged duration to release the entrapped drug without producing any local toxicity at the mucosal region.

Artificial intelligence to deep learning: machine intelligence approach for drug discovery

Drug designing and development is an important area of research for pharmaceutical companies and chemical scientists. However, low efficacy, off-target delivery, time consumption, and high cost impose a hurdle and challenges that impact drug design and discovery. Further, complex and big data from genomics, proteomics, microarray data, and clinical trials also impose an obstacle in the drug discovery pipeline. Artificial intelligence and machine learning technology play a crucial role in drug discovery and development. In other words, artificial neural networks and deep learning algorithms have modernized the area. Machine learning and deep learning algorithms have been implemented in several drug discovery processes such as peptide synthesis, structure-based virtual screening, ligand-based virtual screening, toxicity prediction, drug monitoring and release, pharmacophore modeling, quantitative structure-activity relationship, drug repositioning, polypharmacology, and physiochemical activity. Evidence from the past strengthens the implementation of artificial intelligence and deep learning in this field. Moreover, novel data mining, curation, and management techniques provided critical support to recently developed modeling algorithms. In summary, artificial intelligence and deep learning advancements provide an excellent opportunity for rational drug design and discovery process, which will eventually impact mankind. The primary concern associated with drug design and development is time consumption and production cost. Further, inefficiency, inaccurate target delivery, and inappropriate dosage are other hurdles that inhibit the process of drug delivery and development. With advancements in technology, computer-aided drug design integrating artificial intelligence algorithms can eliminate the challenges and hurdles of traditional drug design and development. Artificial intelligence is referred to as superset comprising machine learning, whereas machine learning comprises supervised learning, unsupervised learning, and reinforcement learning. Further, deep learning, a subset of machine learning, has been extensively implemented in drug design and development. The artificial neural network, deep neural network, support vector machines, classification and regression, generative adversarial networks, symbolic learning, and meta-learning are examples of the algorithms applied to the drug design and discovery process. Artificial intelligence has been applied to different areas of drug design and development process, such as from peptide synthesis to molecule design, virtual screening to molecular docking, quantitative structure-activity relationship to drug repositioning, protein misfolding to protein-protein interactions, and molecular pathway identification to polypharmacology. Artificial intelligence principles have been applied to the classification of active and inactive, monitoring drug release, pre-clinical and clinical development, primary and secondary drug screening, biomarker development, pharmaceutical manufacturing, bioactivity identification and physiochemical properties, prediction of toxicity, and identification of mode of action.

Cellular functions regulated by deubiquitinating enzymes in neurodegenerative diseases

Neurodegenerative diseases are one of the most common diseases in mankind. Although there are reports of several candidates that cause neurodegenerative diseases, the exact mechanism of pathogenesis is poorly understood. The ubiquitin-proteasome system (UPS) is an important posttranslational modification for protein degradation and control of homeostasis. Enzymes such as E1, E2, E3 ligases, and deubiquitinating enzymes (DUBs) participating in UPS, regulate disease-inducing proteins by controlling the degree of ubiquitination. Therefore, the development of treatments targeting enzymes for degenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), and amyotrophic lateral sclerosis (ALS), is emerging as an attractive perspective. In particular, as DUBs are able to regulate one or more degenerative disease-related proteins, the potential as a therapeutic target is even more evident. DUBs influence the regulation of toxic proteins that cause neurodegenerative diseases by not only their removal, but also by regulating signals associated with mitophagy, autophagy, and endoplasmic reticulum-associated degradation (ERAD). In this review, we analyze not only the cellular processes of DUBs, which control neurodegenerative disease-inducing proteins, but also their potentials as a therapeutic agent for neurodegenerative diseases.

An antifouling impedimetric sensor based on zinc oxide embedded polyvinyl alcohol nanoplatelets for wide range dopamine determination in the presence of high concentration ascorbic acid

Dopamine determination is of great importance for the early diagnosis of neurological diseases. However, dopamine sensors mostly encounter important challenges such as surface fouling and interference of co-existing biochemicals. Here, nanoplatelets of zinc oxide embedded polyvinyl alcohol (NP-ZnO/PVA) were utilized for providing an efficient fouling-free surface for selective dopamine determination in concentrations as high as 3 mM of dopamine in the presence of ascorbic acid interference. The fouling-free properties was provided mainly by pH-inducibility of the NP-ZnO/PVA nanocomposite at the rationally adjusted sensing conditions. ZnO plays a vital role in the electrocatalytic oxidation of dopamine, and PVA provides surface functional groups that minimize the surface interactions with interferences or fouling agents. The NP-ZnO/PVA nanocomposite fabrication process was performed by PVA assisted ZnO electro-synthesis onto the surface of fluorine-doped tin oxide (FTO) conducting glass. The fabricated FTO/NP-ZnO/PVA sensor was characterized utilizing FE-SEM, EDX, XRD, TGA-DTG, BET-BJH and FTIR techniques. Impedimetric determination of dopamine was performed in the wide linear range from 20.0 nM to 3.0 mM with a low detection limit of 5.0 nM. The applicability of FTO/NP-ZnO/PVA for dopamine determination was successfully tested in real samples. The NP-ZnO/PVA provides a great prospective to be an efficacious material for the construction of dopamine electrochemical sensing platforms.

Effects of the Hydroethanolic Extract of Lycopodium selago L. on Scopolamine-Induced Memory Deficits in Zebrafish

This scientific research focused on the production of hydroethanolic extract of the plant species Lycopodium selago L. (L. selago) by the ultrasound-assisted extraction (USAE) and the identification of biocompounds with high antioxidant activity is of interest for possible phytotherapeutic treatment against Alzheimer's disease (AD). The extract was phytochemically analyzed to investigate polyphenols, flavonoids, and identify the sesquiterpenoid alkaloid huperzine A (HupA), which is known in the literature for its great relevance in AD. Evaluation and comparison of the antioxidant activity of the extract were performed by four complementary spectrophotometric methods (DPPH, FRAP, ABTS, ORAC). In vitro tests of the extract showed an excellent reciprocal link between the concentration of polyphenols and the measurement of the antioxidant activity of the extract with the sesquiterpenoid HupA. To confirm the antioxidant activity, L. selago hydroethanolic extract was administered in vivo to zebrafish (Danio rerio) with a pattern of scopolamine-induced cognitive impairment. Moreover, this study explored a possible correlation between the expression of oxidative stress markers in the brain tissue with the behavior of the scopolamine zebrafish model. In vivo tests showed that this fern could be used as a nutritional supply and as a phytotherapeutic method to prevent or treat various neurodegenerative diseases that call for high-nutritive-value medications.

Autophagy-targeted therapy to modulate age-related diseases: Success, pitfalls, and new directions

Autophagy is a critical metabolic process that supports homeostasis at a basal level and is dynamically regulated in response to various physiological and pathological processes. Autophagy has some etiologic implications that support certain pathological processes due to alterations in the lysosomal-degradative pathway. Some of the conditions related to autophagy play key roles in highly relevant human diseases, e.g., cardiovascular diseases (15.5%), malignant and other neoplasms (9.4%), and neurodegenerative conditions (3.7%). Despite advances in the discovery of new strategies to treat these age-related diseases, autophagy has emerged as a therapeutic option after preclinical and clinical studies. Here, we discuss the pitfalls and success in regulating autophagy initiation and its lysosome-dependent pathway to restore its homeostatic role and mediate therapeutic effects for cancer, neurodegenerative, and cardiac diseases. The main challenge for the development of autophagy regulators for clinical application is the lack of specificity of the repurposed drugs, due to the low pharmacological uniqueness of their target, including those that target the PI3K/AKT/mTOR and AMPK pathway. Then, future efforts must be conducted to deal with this scenery, including the disclosure of key components in the autophagy machinery that may intervene in its therapeutic regulation. Among all efforts, those focusing on the development of novel allosteric inhibitors against autophagy inducers, as well as those targeting autolysosomal function, and their integration into therapeutic regimens should remain a priority for the field.

Whether short peptides are good candidates for future neuroprotective therapeutics?

Neurodegenerative diseases are a broad group of largely debilitating, and ultimately terminal conditions resulting in progressive degeneration of different brain regions. The observed damages are associated with cell death, structural and functional deficits of neurons, or demyelination. The concept of neuroprotection concerns the administration of the agent, which should reverse some of the damage or prevent further adverse changes. A growing body of evidence suggested that among many classes of compounds considered as neuroprotective agents, peptides derived from natural materials or their synthetic analogs are good candidates. They presented a broad spectrum of activities and abilities to act through diverse mechanisms of action. Biologically active peptides have many properties, including antioxidant, antimicrobial, antiinflammatory, and immunomodulatory effects. Peptides with pro-survival and neuroprotective activities, associated with inhibition of oxidative stress, apoptosis, inflammation and are able to improve cell viability or mitochondrial functions, are also promising molecules of particular interest to the pharmaceutical industries. Peptide multiple activities open the way for broad application potential as therapeutic agents or ingredients of health-promoting functional foods. Significantly, synthetic peptides can be remodeled in numerous ways to have desired features, such as increased solubility or biological stability, as well as selectivity towards a specific receptor, and finally better membrane penetration. This review summarized the most common features of major neurodegenerative disorders, their causes, consequences, and reported new neuroprotective drug development approaches. The author focused on the unique perspectives in neuroprotection and provided a concise survey of short peptides proposed as novel therapeutic agents against various neurodegenerative diseases.

Purines and Pyrimidines: Metabolism, Function and Potential as Therapeutic Options in Neurodegenerative Diseases

Various neurodegenerative disorders have various molecular origins but some common molecular mechanisms. In the current scenario, there are very few treatment regimens present for advanced neurodegenerative diseases. In this context, there is an urgent need for alternate options in the form of natural compounds with an ameliorating effect on patients. There have been individual scattered experiments trying to identify potential values of various intracellular metabolites. Purines and Pyrimidines, which are vital molecules governing various aspects of cellular biochemical reactions, have been long sought as crucial candidates for the same, but there are still many questions that go unanswered. Some critical functions of these molecules associated with neuromodulation activities have been identified. They are also known to play a role in foetal neurodevelopment, but there is a lacuna in understanding their mechanisms. In this review, we have tried to assemble and identify the importance of purines and pyrimidines, connecting them with the prevalence of neurodegenerative diseases. The leading cause of this class of diseases is protein misfolding and the formation of amyloids. A direct correlation between loss of balance in cellular homeostasis and amyloidosis is yet an unexplored area. This review aims at bringing the current literature available under one umbrella serving as a foundation for further extensive research in this field of drug development in neurodegenerative diseases.

Is There Any Association Between Neurodegenerative Diseases and Periodontitis? A Systematic Review

Background: Neurodegenerative diseases are a group of progressive disorders that affect the central nervous system (CNS) such as Alzheimer, Parkinson, and multiple sclerosis. Inflammation plays a critical role in the onset and progression of these injuries. Periodontitis is considered an inflammatory disease caused by oral biofilms around the tooth-supporting tissues, leading to a systemic and chronic inflammatory condition. Thus, this systematic review aimed to search for evidence in the association between neurodegenerative disorders and periodontitis.

Methods: This systematic review was registered at International Prospective Register of Systematic Reviews (PROSPERO) under the code CRD 42016038327. The search strategy was performed in three electronic databases and one gray literature source—PubMed, Scopus, Web of Science, and OpenGrey, based on the PECO acronym: observational studies in humans (P) in which a neurodegenerative disease was present (E) or absent (C) to observe an association with periodontitis (O). The Fowkes and Fulton checklist was used to critically appraise the methodological quality and the risk of bias of individual studies. The quality of evidence was assessed by the Grading of Recommendations Assessment, Development and Evaluation (GRADE).

Results: From 534 articles found, 12 were included, of which eight were case–control, three were cross-sectional, and one was a cohort, giving a total of 3,460 participants. All the included studies reported an association between some neurodegenerative diseases and periodontitis and presented a low risk of bias. According to the GRADE approach, the level of evidence of probing pocket depth was considered very low due to the significant heterogeneity across the studies' upgrading imprecision and inconsistency.

Conclusions: Although all the included studies in this review reported an association between neurodegenerative diseases and periodontitis, the level of evidence was classified to be very low, which suggests a cautious interpretation of the results.

Cell Death via Lipid Peroxidation and Protein Aggregation Diseases

Lipid peroxidation of cellular membranes is a complicated cellular event, and it is both the cause and result of various diseases, such as ischemia-reperfusion injury, neurodegenerative diseases, and atherosclerosis. Lipid peroxidation causes non-apoptotic cell death, which is associated with cell fate determination: survival or cell death. During the radical chain reaction of lipid peroxidation, various oxidized lipid products accumulate in cells, followed by organelle dysfunction and the induction of non-apoptotic cell death. Highly reactive oxidized products from unsaturated fatty acids are detected under pathological conditions. Pathological protein aggregation is the general cause of these diseases. The cellular response to misfolded proteins is well-known as the unfolded protein response (UPR) and it is partially concomitant with the response to lipid peroxidation. Moreover, the association between protein aggregation and non-apoptotic cell death by lipid peroxidation is attracting attention. The link between lipid peroxidation and protein aggregation is a matter of concern in biomedical fields. Here, we focus on lethal protein aggregation in non-apoptotic cell death via lipid peroxidation. We reviewed the roles of protein aggregation in the initiation and execution of non-apoptotic cell death. We also considered the relationship between protein aggregation and oxidized lipid production. We provide an overview of non-apoptotic cell death with a focus on lipid peroxidation for therapeutic targeting during protein aggregation diseases.

CRISPR/Cas9 Technology as a Modern Genetic Manipulation Tool for Recapitulating of Neurodegenerative Disorders in Large Animal Models

BACKGROUND

Neurodegenerative diseases are often the consequence of alterations in structures and functions of the Central Nervous System (CNS) in patients. Despite obtaining massive genomic information concerning the molecular basis of these diseases and since the neurological disorders are multifactorial, causal connections between pathological pathways at the molecular level and CNS disorders development have remained obscure and need to be elucidated to a great extent.

OBJECTIVE

Animal models serve as accessible and valuable tools for understanding and discovering the roles of causative factors in the development of neurodegenerative disorders and finding appropriate treatments. Contrary to rodents and other small animals, large animals, especially non-human primates (NHPs), are remarkably similar to humans; hence, they establish suitable models for recapitulating the main human's neuropathological manifestations that may not be seen in rodent models. In addition, they serve as useful models to discover effective therapeutic targets for neurodegenerative disorders due to their similarity to humans in terms of physiology, evolutionary distance, anatomy, and behavior.

METHODS

In this review, we recommend different strategies based on the CRISPR-Cas9 system for generating animal models of human neurodegenerative disorders and explaining in vivo CRISPR-Cas9 delivery procedures that are applied to disease models for therapeutic purposes.

RESULTS

With the emergence of CRISPR/Cas9 as a modern specific gene-editing technology in the field of genetic engineering, genetic modification procedures such as gene knock-in and knock-out have become increasingly easier compared to traditional gene targeting techniques. Unlike the old techniques, this versatile technology can efficiently generate transgenic large animal models without the need to complicate lab instruments. Hence, these animals can accurately replicate the signs of neurodegenerative disorders.

CONCLUSION

Preclinical applications of CRISPR/Cas9 gene-editing technology supply a unique opportunity to establish animal models of neurodegenerative disorders with high accuracy and facilitate perspectives for breakthroughs in the research on the nervous system disease therapy and drug discovery. Furthermore, the useful outcomes of CRISPR applications in various clinical phases are hopeful for their translation to the clinic in a short time.

The Diagnostic Potential of Amyloidogenic Proteins

Neurodegenerative disorders are a highly prevalent class of diseases, whose pathological mechanisms start before the appearance of any clear symptoms. This fact has prompted scientists to search for biomarkers that could aid early treatment. These currently incurable pathologies share the presence of aberrant aggregates called amyloids in the nervous system, which are composed of specific proteins. In this review, we discuss how these proteins, their conformations and modifications could be exploited as biomarkers for diagnostic purposes. We focus on proteins that are associated with the most prevalent neurodegenerative disorders, including Alzheimer's and Parkinson's diseases, amyotrophic lateral sclerosis, and frontotemporal dementia. We also describe current challenges in detection, the most recent techniques with diagnostic potentials and possible future developments in diagnosis.

Effect of alcohol on the central nervous system to develop neurological disorder: pathophysiological and lifestyle modulation can be potential therapeutic options for alcohol-induced neurotoxication

The central nervous system (CNS) is the major target for adverse effects of alcohol and extensively promotes the development of a significant number of neurological diseases such as stroke, brain tumor, multiple sclerosis (MS), Alzheimer's disease (AD), and amyotrophic lateral sclerosis (ALS). Excessive alcohol consumption causes severe neuro-immunological changes in the internal organs including irreversible brain injury and it also reacts with the defense mechanism of the blood-brain barrier (BBB) which in turn leads to changes in the configuration of the tight junction of endothelial cells and white matter thickness of the brain. Neuronal injury associated with malnutrition and oxidative stress-related BBB dysfunction may cause neuronal degeneration and demyelination in patients with alcohol use disorder (AUD); however, the underlying mechanism still remains unknown. To address this question, studies need to be performed on the contributing mechanisms of alcohol on pathological relationships of neurodegeneration that cause permanent neuronal damage. Moreover, alcohol-induced molecular changes of white matter with conduction disturbance in neurotransmission are a likely cause of myelin defect or axonal loss which correlates with cognitive dysfunctions in AUD. To extend our current knowledge in developing a neuroprotective environment, we need to explore the pathophysiology of ethanol (EtOH) metabolism and its effect on the CNS. Recent epidemiological studies and experimental animal research have revealed the association between excessive alcohol consumption and neurodegeneration. This review supports an interdisciplinary treatment protocol to protect the nervous system and to improve the cognitive outcomes of patients who suffer from alcohol-related neurodegeneration as well as clarify the pathological involvement of alcohol in causing other major neurological disorders.

The emerging role of probiotics in neurodegenerative diseases: new hope for Parkinson's disease?

Neurodegenerative disease etiology is still unclear, but different contributing factors, such as lifestyle and genetic factors are involved. Altered components of the gut could play a key role in the gut-brain axis, which is a bidirectional system between the central nervous system and the enteric nervous system. Variations in the composition of the gut microbiota and its function between healthy people and patients have been reported for a variety of human disorders comprising metabolic, autoimmune, cancer, and, notably, neurodegenerative disorders. Diet can alter the microbiota composition, affecting the gut-brain axis function. Different nutraceutical interventions have been devoted to normalizing gut microbiome dysbiosis and to improving biological outcomes in neurological conditions, including the use of probiotics. Preclinical and clinical investigations discussed in this review strengthen the correlation between intestinal microbiota and brain and the concept that modifying the microbiome composition may improve brain neurochemistry, modulating different pathways. This review will discuss the potential use of probiotics for Parkinson's disease prevention or treatment or as adjuvant therapy, confirming that gut microbiota modulation influences different pro-survival pathways. Future investigations in Parkinson's disease should consider the role of the gut-brain axis and additional comprehension of the underlying mechanisms is extremely necessary.

High-Throughput Screening Platforms in the Discovery of Novel Drugs for Neurodegenerative Diseases

Neurodegenerative diseases (NDDs) are incurable and debilitating conditions that result in progressive degeneration and/or death of nerve cells in the central nervous system (CNS). Identification of viable therapeutic targets and new treatments for CNS disorders and in particular, for NDDs is a major challenge in the field of drug discovery. These difficulties can be attributed to the diversity of cells involved, extreme complexity of the neural circuits, the limited capacity for tissue regeneration, and our incomplete understanding of the underlying pathological processes. Drug discovery is a complex and multidisciplinary process. The screening attrition rate in current drug discovery protocols mean that only one viable drug may arise from millions of screened compounds resulting in the need to improve discovery technologies and protocols to address the multiple causes of attrition. This has identified the need to screen larger libraries where the use of efficient high-throughput screening (HTS) becomes key in the discovery process. HTS can investigate hundreds of thousands of compounds per day. However, if fewer compounds could be screened without compromising the probability of success, the cost and time would be largely reduced. To that end, recent advances in computer-aided design, in silico libraries, and molecular docking software combined with the upscaling of cell-based platforms have evolved to improve screening efficiency with higher predictability and clinical applicability. We review, here, the increasing role of HTS in contemporary drug discovery processes, in particular for NDDs, and evaluate the criteria underlying its successful application. We also discuss the requirement of HTS for novel NDD therapies and examine the major current challenges in validating new drug targets and developing new treatments for NDDs.

Targeted Delivery for Neurodegenerative Disorders Using Gene Therapy Vectors: Gene Next Therapeutic Goals

The technique of gene therapy, ever since its advent nearly fifty years ago, has been utilized by scientists as a potential treatment option for various disorders. This review discusses some of the major neurodegenerative diseases (NDDs) like Alzheimer's disease (AD), Parkinson's Disease (PD), Motor neuron diseases (MND), Spinal Muscular Atrophy (SMA), Huntington's Disease (HD), Multiple Sclerosis (MS), etc. and their underlying genetic mechanisms along with the role that gene therapy can play in combating them. The pathogenesis and the molecular mechanisms specifying the altered gene expression of each of these NDDs have also been discussed in elaboration. The use of gene therapy vectors can prove to be an effective tool in the field of curative modern medicine for the generations to come. Therefore, consistent efforts and progressive research towards its implementation can provide us with powerful treatment options for disease conditions that have so far been considered as incurable.

Cerebrolysin for stroke, neurodegeneration, and traumatic brain injury: review of the literature and outcomes

Cerebrolysin therapy has the potential to significantly aid in the treatment of a wide variety of debilitating neurological diseases including ischemic strokes, neurodegenerative disorders, and traumatic brain injuries. Although Cerebrolysin is not approved for use in the USA, it is used clinically in over 50 countries worldwide. In this review, we focus on outlining the role that Cerebrolysin has in stimulating the molecular signaling pathways that are critical for neurological regeneration and support. An extensive evaluation of these signaling pathways reveals that Cerebrolysin has the potential to intervene in a diverse array of pathophysiological causes of neurological diseases. In the clinical setting, Cerebrolysin is generally safe for human use and has provided functional improvement when used as an adjunct treatment. However, our literature review revealed inconsistent results, as several clinical studies suggested that Cerebrolysin treatment has minor clinical relevance and did not have significant advantages over a placebo. In conclusion, we found that Cerebrolysin therapy can potentially play a major role in the treatment of many neurological diseases. Nevertheless, there remains much to be elucidated about the efficacy of this treatment for specific neurological conditions, and more robust clinical data is needed to reach a consensus and properly define the therapeutic role of Cerebrolysin.

Centella asiatica promotes early differentiation, axodendritic maturation and synaptic formation in primary hippocampal neurons

BACKGROUND

Centella asiatica is a 'medhya-rasayana (nootrophic or memory booster)' herb that has been indicated in Ayurveda for improving memory function and treating dementia disorders. Although the neuroprotective effects of C. asiatica have been reported in earlier studies, the information on whether this nootropic herb could promote early differentiation and development of axon and dendrites in primary hippocampal neurons is currently limited.

THE AIM OF THE STUDY

To investigate the effects of C. asiatica and asiatic acid, one of the principal active constituents of C. asiatica, on the various stages of neuronal polarity, including early neuronal differentiation, axonal outgrowth, dendritic arborization, axonal maturation, and synaptic formation.

MATERIALS AND METHODS

Embryonic rat hippocampal neurons were incubated with C. asiatica leaf extract (CAE) or asiatic acid. After an indicated time, neurons were fixed and immunolabeled to visualize the neuronal morphology. Morphometric analyses for early neuronal differentiation, axonal and dendritic maturation and synaptogenesis were performed using Image J software. Neuronal viability was determined using trypan blue exclusion assay.

RESULTS

CAE at varying concentrations ranging from 3.75 to 15 μg/mL enhanced neurite outgrowth with the highest optimal concentration of 7.5 μg/mL. The effects of CAE commenced immediately after cell seeding, as indicated by its accelerating effect on neuronal differentiation. Subsequently, CAE significantly elaborated dendritic and axonal morphology and facilitated synapse formation. Asiatic acid also facilitated neurite outgrowth, but to a lesser extent than CAE.

CONCLUSION

These findings revealed that CAE exerted its modulatory effects in every stage of neuronal development, supporting its previously claimed neurotrophic function and suggest that this natural nootropic and its active component asiatic acid can be further investigated to explore a promising solution for degenerative brain disorders and injuries.

Alzheimer's, Parkinson's Disease and Amyotrophic Lateral Sclerosis Gene Expression Patterns Divergence Reveals Different Grade of RNA Metabolism Involvement

Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS) are neurodegenerative disorders characterized by a progressive degeneration of the central or peripheral nervous systems. A central role of the RNA metabolism has emerged in these diseases, concerning mRNAs processing and non-coding RNAs biogenesis. We aimed to identify possible common grounds or differences in the dysregulated pathways of AD, PD, and ALS. To do so, we performed RNA-seq analysis to investigate the deregulation of both coding and long non-coding RNAs (lncRNAs) in ALS, AD, and PD patients and controls (CTRL) in peripheral blood mononuclear cells (PBMCs). A total of 293 differentially expressed (DE) lncRNAs and 87 mRNAs were found in ALS patients. In AD patients a total of 23 DE genes emerged, 19 protein coding genes and four lncRNAs. Through Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analyses, we found common affected pathways and biological processes in ALS and AD. In PD patients only five genes were found to be DE. Our data brought to light the importance of lncRNAs and mRNAs regulation in three principal neurodegenerative disorders, offering starting points for new investigations on deregulated pathogenic mechanisms.

Common Factors in Neurodegeneration: A Meta-Study Revealing Shared Patterns on a Multi-Omics Scale

Neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), and amyotrophic lateral sclerosis (ALS) are heterogeneous, progressive diseases with frequently overlapping symptoms characterized by a loss of neurons. Studies have suggested relations between neurodegenerative diseases for many years (e.g., regarding the aggregation of toxic proteins or triggering endogenous cell death pathways). We gathered publicly available genomic, transcriptomic, and proteomic data from 177 studies and more than one million patients to detect shared genetic patterns between the neurodegenerative diseases on three analyzed omics-layers. The results show a remarkably high number of shared differentially expressed genes between the transcriptomic and proteomic levels for all conditions, while showing a significant relation between genomic and proteomic data between AD and PD and AD and ALS. We identified a set of 139 genes being differentially expressed in several transcriptomic experiments of all four diseases. These 139 genes showed overrepresented gene ontology (GO) Terms involved in the development of neurodegeneration, such as response to heat and hypoxia, positive regulation of cytokines and angiogenesis, and RNA catabolic process. Furthermore, the four analyzed neurodegenerative diseases (NDDs) were clustered by their mean direction of regulation throughout all transcriptomic studies for this set of 139 genes, with the closest relation regarding this common gene set seen between AD and HD. GO-Term and pathway analysis of the proteomic overlap led to biological processes (BPs), related to protein folding and humoral immune response. Taken together, we could confirm the existence of many relations between Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis on transcriptomic and proteomic levels by analyzing the pathways and GO-Terms arising in these intersections. The significance of the connection and the striking relation of the results to processes leading to neurodegeneration between the transcriptomic and proteomic data for all four analyzed neurodegenerative diseases showed that exploring many studies simultaneously, including multiple omics-layers of different neurodegenerative diseases simultaneously, holds new relevant insights that do not emerge from analyzing these data separately. Furthermore, the results shed light on processes like the humoral immune response that have previously been described only for certain diseases. Our data therefore suggest human patients with neurodegenerative diseases should be addressed as complex biological systems by integrating multiple underlying data sources.

Natural Approaches for Neurological Disorders-The Neuroprotective Potential of Codium tomentosum

Parkinson's disease (PD) is the second most common neurodegenerative disorder, and is characterized by a progressive degeneration of the dopaminergic neurons in the substantianigra. Although not completely understood, several abnormal cellular events are known to be related with PD progression, such as oxidative stress, mitochondrial dysfunction and apoptosis. Accordingly, the aim of this study was to evaluate the neuroprotective effects of Codium tomentosum enriched fractions in a neurotoxicity model mediated by 6-hydroxydopamine (6-OHDA) on SH-SY5Y human cells, and the disclosure of their mechanisms of action. Additionally, a preliminary chemical screening of the most promising bioactive fractions of C. tomentosum was carried out by GC-MS analysis. Among the tested fractions, four samples exhibited the capacity to revert the neurotoxicity induced by 6-OHDA to values higher or similar to the vitamin E (90.11 ± 3.74% of viable cells). The neuroprotective effects were mediated by the mitigation of reactive oxygen species (ROS) generation, mitochondrial dysfunctions and DNA damage, together with the reduction of Caspase-3 activity. Compounds belonging to different chemical classes, such as terpenes, alcohols, carboxylic acids, aldehydes, esters, ketones, saturated and unsaturated hydrocarbons were tentatively identified by GC-MS. The results show that C. tomentosum is a relevant source of neuroprotective agents, with particular interest for preventive therapeutics.

International R&D Collaboration for a Global Aging Society: Focusing on Aging-Related National-Funded Projects

An international research and development (R&D) collaboration for aging-related projects is necessary to alleviate the severe economic/healthcare/humanitarian challenges of a global aging society. This study presents a practical/systematic framework that enables the provision of information on the research goals, the status of science and technology, and action plans of aging-related program development processes. We used data on aging-related national-funded projects from the United States of America, the European Union, the United Kingdom, Japan, and Korea. We collected data on 6318 national-funded projects, subsequently designating research fields to each project. By analyzing the content of the projects, their representative research fields, and the associated keywords, we assessed the general goals of six different research fields. To recognize the current scientific capabilities of these research fields, we divided the projects by clusters. We provided information on research organizations, specific goals (i.e., project title), project periods, and the funding related to the projects. These may be used by stakeholders in various governments/institutions/industries during future discussions regarding the establishment of an international R&D collaboration strategy. The approach we proposed may facilitate the linkage between knowledge and action during strategy development by maximizing scientific legitimacy, developing consensual knowledge, and minimizing diverging opinions among stakeholders.

Lipid Peroxidation and Antioxidant Supplementation in Neurodegenerative Diseases: A Review of Human Studies

Being characterized by progressive and severe damage in neuronal cells, neurodegenerative diseases (NDDs) are the major cause of disability and morbidity in the elderly, imposing a significant economic and social burden. As major components of the central nervous system, lipids play important roles in neural health and pathology. Disturbed lipid metabolism, particularly lipid peroxidation (LPO), is associated with the development of many NDDs, including Alzheimer’s disease (AD), Parkinson’s disease (PD), and amyotrophic lateral sclerosis (ALS), all of which show elevated levels of LPO products and LPO-modified proteins. Thus, the inhibition of neuronal oxidation might slow the progression and reduce the severity of NDD; natural antioxidants, such as polyphenols and antioxidant vitamins, seem to be the most promising agents. Here, we summarize current literature data that were derived from human studies on the effect of natural polyphenols and vitamins A, C, and E supplementation in patients with AD, PD, and ALS. Although these compounds may reduce the severity and slow the progression of NDD, research gaps remain in antioxidants supplementation in AD, PD, and ALS patients, which indicates that further human studies applying antioxidant supplementation in different forms of NDDs are urgently needed.

Therapeutic Potential of Porcine Liver Decomposition Product: New Insights and Perspectives for Microglia-Mediated Neuroinflammation in Neurodegenerative Diseases

It is widely accepted that microglia-mediated inflammation contributes to the progression of neurodegenerative diseases; however, the precise mechanisms through which these cells contribute remain to be elucidated. Microglia, as the primary immune effector cells of the brain, play key roles in maintaining central nervous system (CNS) homeostasis. Microglia are located throughout the brain and spinal cord and may account for up to 15% of all cells in the brain. Activated microglia express pro-inflammatory cytokines that act on the surrounding brain and spinal cord. Microglia may also play a detrimental effect on nerve cells when they gain a chronic inflammatory function and promote neuropathologies. A key feature of microglia is its rapid morphological change upon activation, characterized by the retraction of numerous fine processes and the gradual acquisition of amoeba-like shapes. These morphological changes are also accompanied by the expression and secretion of inflammatory molecules, including cytokines, chemokines, and lipid mediators that promote systemic inflammation during neurodegeneration. This may be considered a protective response intended to limit further injury and initiate repair processes. We previously reported that porcine liver decomposition product (PLDP) induces a significant increase in the Hasegawa’s Dementia Scale-Revised (HDS-R) score and the Wechsler Memory Scale (WMS) in a randomized, double-blind, placebo-controlled study in healthy humans. In addition, the oral administration of porcine liver decomposition product enhanced visual memory and delayed recall in healthy adults. We believe that PLDP is a functional food that aids cognitive function. In this review, we provide a critical assessment of recent reports of lysophospholipids derived from PLDP, a rich source of phospholipids. We also highlight some recent findings regarding bidirectional interactions between lysophospholipids and microglia and age-related neurodegenerative diseases such as dementia and Alzheimer’s disease.

Traditional Korean herbal formulae, Yuk-Mi-Ji-Hwang-Tang, ameliorates impairment of hippocampal memory ability by chronic restraint stress of mouse model

ETHNOPHARMACOLOGICAL RELEVANCE

Yuk-Mi-Jihwang-Tang (YJT) has been popularly prescribed to treat aging related disorders over than hundreds of years in East Asia countries.

AIM OF THE STUDY

To investigate possible modulatory actions of YJT on chronic restraint stress (CRS)-induced neurodegeneration on hippocampus neuronal injuries.

MATERIALS AND METHODS

Mice were orally administered with YJT (100, 200, or 400 mg/kg) or ascorbic acid (100 mg/kg) before 4 h of stress for 28 days. Morris water maze task was completed from day 24th to 28th, and stress hormones and biochemical analyzes were measured.

RESULTS

Four weeks of the CRS abnormally affected memory impairments by measurement of escape latency and time spent in the target quadrant. Additionally, neurotransmitters were also drastically altered in serum or hippocampus protein levels by CRS. Gene expressions for 5-hydroxytryptamine (5-HT) receptor, 5-HT-transport, and tryptophan hydroxylase were also altered, whereas YJT led to normalize the above alterations. Additionally, YJT also beneficially worked on endogenous redox system as well as inflammatory reactions in the hippocampal neurons. We observed that hippocampal excitotoxicity was induced by CRS which were evidenced by depletion of phosphor-cAMP response element-binding protein, brain-derived neurotrophic factor, nuclear factor erythroid-2-related factor 2, heme oxygenase-1 and abnormally increases of acetylcholine esterase activities in hippocampus protein levels; however, YJT considerably improved the above pathological conditions.

CONCLUSIONS

Our findings supported YJT enhance memory function via regulation of hippocampal excitotoxicity-derived memory impairment, stress hormone, and endogenous redox, respectively.

Neoglycosylated Collagen: Effect on Neuroblastoma F-11 Cell Lines

The regeneration of the nervous system is a challenging task. Currently, regenerative medicine approaches that exploit nature-inspired cues are being studied and hold great promise. The possibility to use protein-based matrices functionalized with small oligo- and monosaccharides is of interest since these can be finely tuned to better mimic the native environment. Collagen has been selected as a promising material that has the potential to be further tailored to incorporate carbohydrates in order to drive cell behavior towards neuroregeneration. Indeed, the grafting of carbohydrates to collagen 2D matrices is proved to enhance its biological significance. In the present study, collagen 2D matrices were grafted with different carbohydrate epitopes, and their potential to drive F-11 neuroblastoma cells towards neuronal differentiation was evaluated. Collagen functionalized with α-glucosides was able to differentiate neuroblastoma cells into functional neurons, while sialyl α-(2→6)-galactosides stimulated cell proliferation.

Gene Therapy for Neurodegenerative Diseases: Slowing Down the Ticking Clock

Gene therapy is an emerging and powerful therapeutic tool to deliver functional genetic material to cells in order to correct a defective gene. During the past decades, several studies have demonstrated the potential of AAV-based gene therapies for the treatment of neurodegenerative diseases. While some clinical studies have failed to demonstrate therapeutic efficacy, the use of AAV as a delivery tool has demonstrated to be safe. Here, we discuss the past, current and future perspectives of gene therapies for neurodegenerative diseases. We also discuss the current advances on the newly emerging RNAi-based gene therapies which has been widely studied in preclinical model and recently also made it to the clinic.

Olive Leaves and Hibiscus Flowers Extracts-Based Preparation Protect Brain from Oxidative Stress-Induced Injury

Oxidative stress (OS) arising from tissue redox imbalance, critically contributes to the development of neurodegenerative disorders. Thus, natural compounds, owing to their antioxidant properties, have promising therapeutic potential. Pres phytum (PRES) is a nutraceutical product composed of leaves- and flowers-extracts of Olea europaea L. and Hibiscus sabdariffa L., respectively, the composition of which has been characterized by HPLC coupled to a UV-Vis and QqQ-Ms detector. As PRES possess antioxidant, antiapoptotic and anti-inflammatory properties, the aim of this study was to assess its neuroprotective effects in human neuroblastoma SH-SY5Y cells and in rat brain slices subjected to OS. PRES (1–50 µg/mL) reverted the decrease in viability as well as the increase in sub-diploid-, DAPI-and annexin V-positive-cells, reduced ROS formation, recovered the mitochondrial potential and caspase-3 and 9 activity changes caused by OS. PRES (50–100 µg/mL) neuroprotective effects occurred also in rat brain slices subjected to H₂O₂ challenge. Finally, as the neuroprotective potential of PRES is strictly related to its penetration into the brain and a relatively good pharmacokinetic profile, an in-silico prediction of its components drug-like properties was carried out. The present results suggest the possibility of PRES as a nutraceutical, which could help in preventing neurodegenerative diseases.

Is the Immunological Response a Bottleneck for Cell Therapy in Neurodegenerative Diseases?

Neurodegenerative disorders such as Parkinson's (PD) and Huntington's disease (HD) are characterized by a selective detrimental impact on neurons in a specific brain area. Currently, these diseases have no cures, although some promising trials of therapies that may be able to slow the loss of brain cells are underway. Cell therapy is distinguished by its potential to replace cells to compensate for those lost to the degenerative process and has shown a great potential to replace degenerated neurons in animal models and in clinical trials in PD and HD patients. Fetal-derived neural progenitor cells, embryonic stem cells or induced pluripotent stem cells are the main cell sources that have been tested in cell therapy approaches. Furthermore, new strategies are emerging, such as the use of adult stem cells, encapsulated cell lines releasing trophic factors or cell-free products, containing an enriched secretome, which have shown beneficial preclinical outcomes. One of the major challenges for these potential new treatments is to overcome the host immune response to the transplanted cells. Immune rejection can cause significant alterations in transplanted and endogenous tissue and requires immunosuppressive drugs that may produce adverse effects. T-, B-lymphocytes and microglia have been recognized as the main effectors in striatal graft rejection. This review aims to summarize the preclinical and clinical studies of cell therapies in PD and HD. In addition, the precautions and strategies to ensure the highest quality of cell grafts, the lowest risk during transplantation and the reduction of a possible immune rejection will be outlined. Altogether, the wide-ranging possibilities of advanced therapy medicinal products (ATMPs) could make therapeutic treatment of these incurable diseases possible in the near future.

The In Vitro Anti-amyloidogenic Activity of the Mediterranean Red Seaweed Halopithys Incurva

Neurodegenerative diseases are generally characterized by the presence of neurotoxic amyloid aggregates underlying progressive neuronal death. Since ancient times, natural compounds have been used as curative agents for human health. Amyloid research is constantly looking for safe natural molecules capable of blocking toxic amyloid aggregates’ formation. From the marine environment, seaweeds are recognized as rich reservoirs of molecules with multiple bioactivities, including the anti-amyloidogenic activity. Here, hydroalcoholic extracts of two seasonal samples of the Mediterranean red seaweed Halophytis incurva (HIEs) were characterized by the HPLC-DAD-MS analysis. The H. incurva anti-amyloidogenic role was explored by incubating both HIEs with hen egg white lysozyme (HEWL), a well-known protein model widely used in amyloid aggregation experiments. The aggregation kinetics and morphological analysis of amyloid aggregates were performed by ThT and AFM analysis, respectively, while their cytotoxicity on SH-SY5Y human neuroblastoma cells was examined by MTT assay. HIEs showed a different efficacy, probably dependent on their metabolic composition, both in inhibiting amyloid fibrillation and in obtaining short and less toxic pre-fibrillary aggregates. Overall, this work sheds light, for the first time, on a Mediterranean red seaweed as a promising renewable resource of bioactive compounds, potentially useful in preventing the formation of toxic amyloid aggregates.

Extracts Characterization and In Vitro Evaluation of Potential Immunomodulatory Activities of the Moss Hypnum cupressiforme Hedw

Recently, there has been an increasing interest in the chemistry and biological potential of mosses, since a large number of biologically active compounds have been found within these species. This study aimed at examining the chemical composition and immunomodulatory potential (antioxidant, antidiabetic, anti-neuroinflammatory/antineurodegenerative, and antitumor activities) of moss Hypnum cupressiforme Hedw. extracts. Corresponding extracts have been obtained applying Soxhlet extractor. The chemical characterization was performed using spectrophotometric assays and liquid chromatography–mass spectrometry (LC-MS). The extracts were analyzed for antioxidant activity and for inhibitory activities on α-glucosidase, α-amylase, acetylcholinesterase, and tyrosinase. Additionally, extracts were tested against four cell lines—MRC-5, BV2, HCT-116, and MDA-MB-231—for antitumor and anti-inflammatory activities. Chemical analysis of extracts revealed the presence of flavonoids, phenolic acids, and triterpenoids. Major compounds identified by LC-MS in H. cupressiforme were kaempferol and five phenolic acids: p-hydroxybenzoic, protocatechuic, p-coumaric, gallic, and caffeic acid. According to biochemical assays the investigated extracts exhibited significant immunomodulatory potential. Significant antiproliferative potential against MDA-MB-231 cells has been observed together with the promising anti-neuroinflammatory application. The obtained data suggest that moss H. cupressiforme is a valuable natural source of biologically active compounds with potential application in the pharmaceutical industry.

Potential Thai medicinal plants for neurodegenerative diseases: A review focusing on the anti-glutamate toxicity effect

Neurodegenerative diseases (NDD) are a range of debilitating conditions of the brain involving progressive loss of neurons, many of which are still currently incurable despite enormous efforts on drug discovery and development in the past decade. As NDD is closely linked to old age, the rapid worldwide growth in the aging population contributes to an increasing number of people with one of these incurable diseases and therefore it is considered a significant global health issue. There is an urgent need for novel effective treatments for NDD, and many new research strategies are centered on traditional medicine as an alternative or complementary solution. Several previous findings have suggested that glutamate toxicity drives neurodegeneration in many NDD, and the medicinal plants with anti-glutamate toxicity properties can be potentially used for their treatment. In order to obtain data relating to natural products against glutamate toxicity, six candidate plant species of Thailand were identified. Studies utilizing these herbs were searched for using the herb name (Latin and common names) along with the term "glutamate" in the following databases across all available years: PubMed, Scopus, and Google Scholar. This review emphasizes the importance of glutamate toxicity in NDD and summarizes individual plants and their active constituents with the mechanism of action against glutamate toxicity-mediated neuronal cell death that could be a promising resource for future NDD therapy.

TAXONOMY CLASSIFICATION BY EVISE

Alzheimer's disease, Neurodegenerative diseases, Cell culture, Molecular Biology, Traditional herbal medicine, Oxidative stress, Glutamate neurotransmitter.