Gene therapy for neurological disorders

Amyotrophic Lateral Sclerosis (ALS) Type 8: A Narrative Review

Amyotrophic lateral sclerosis type 8 (ALS8) is a rare familial subtype of ALS caused by mutations in the vesicle-associated membrane protein-associated protein B (VAPB) gene, particularly the p.P56S mutation. It is distinguished by slower disease progression and an earlier onset compared to sporadic ALS forms, along with unique clinical features such as severe cramping, fasciculations, postural tremors, and cognitive and behavioral impairments. Although current pharmacological options, such as riluzole, edaravone, and sodium phenylbutyrate/taurursodiol, provide modest benefits, they fail to address the underlying genetic mechanisms of ALS8. Emerging gene therapies, RNA-based interventions, and stem cell approaches hold promise for precision-targeted treatments but face challenges in clinical application. Symptom management strategies, including respiratory, nutritional, and psychological support, are crucial for improving patient outcomes and quality of life. Despite significant progress in understanding the genetic and molecular pathogenesis of ALS8, its rarity, phenotypic variability, and limited clinical data pose challenges to therapeutic advancements. This narrative review highlights current therapeutic strategies, the unique clinical trajectory of ALS8, and potential pathways for innovative, subtype-specific interventions, emphasizing the need for multidisciplinary and targeted approaches to optimize care for this distinct ALS subtype.

Stem cell therapeutics and gene therapy for neurologic disorders

Rapid advances in biological knowledge and technological innovation have greatly advanced the fields of stem cell and gene therapies to combat a broad spectrum of neurologic disorders. Researchers are currently exploring a variety of stem cell types (e.g., embryonic, progenitor, induced pluripotent) and various transplantation strategies, each with its own advantages and drawbacks. Similarly, various gene modification techniques (zinc finger, TALENs, CRISPR-Cas9) are employed with various delivery vectors to modify underlying genetic contributors to neurologic disorders. While these two individual fields continue to blaze new trails, it is the combination of these technologies which enables genetically engineered stem cells and vastly increases investigational and therapeutic opportunities. The capability to culture and expand stem cells outside the body, along with their potential to correct genetic abnormalities in patient-derived cells or enhance cells with extra gene products, unleashes the full biological potential for innovative, multifaceted approaches to treat complex neurological disorders. In this review, we provide an overview of stem cell and gene therapies in the context of neurologic disorders, highlighting recent advances and current shortcomings, and discuss prospects for future therapies in clinical settings.

A comprehensive update on genetic inheritance, epigenetic factors, associated pathology, and recent therapeutic intervention by gene therapy in schizophrenia

Schizophrenia is a severe psychological disorder in which reality is interpreted abnormally by the patient. The symptoms of the disease include delusions and hallucinations, associated with extremely disordered behavior and thinking, which may affect the daily lives of the patients. Advancements in technology have led to understanding the dynamics of the disease and the identification of the underlying causes. Multiple investigations prove that it is regulated genetically, and epigenetically, and is affected by environmental factors. The molecular and neural pathways linked to the regulation of schizophrenia have been extensively studied. Over 180 Schizophrenic risk loci have now been recognized due to several genome-wide association studies (GWAS). It has been observed that multiple transcription factors (TF) binding-disrupting single nucleotide polymorphisms (SNPs) have been related to gene expression responsible for the disease in cerebral complexes. Copy number variation, SNP defects, and epigenetic changes in chromosomes may cause overexpression or underexpression of certain genes responsible for the disease. Nowadays, gene therapy is being implemented for its treatment as several of these genetic defects have been identified. Scientists are trying to use viral vectors, miRNA, siRNA, and CRISPR technology. In addition, nanotechnology is also being applied to target such genes. The primary aim of such targeting was to either delete or silence such hyperactive genes or induce certain genes that inhibit the expression of these genes. There are challenges in delivering the gene/DNA to the site of action in the brain, and scientists are working to resolve the same. The present article describes the basics regarding the disease, its causes and factors responsible, and the gene therapy solutions available to treat this disease.

Gene therapy of adeno-associated virus (AAV) vectors in preclinical models of ischemic stroke

Stroke has been associated with devastating clinical outcomes, with current treatment strategies proving largely ineffective. Therefore, there is a need to explore alternative treatment options for addressing post-stroke functional deficits. Gene therapy utilizing adeno-associated viruses (AAVs) as a critical gene vector delivering genes to the central nervous system (CNS) gene delivery has emerged as a promising approach for treating various CNS diseases. This review aims to provide an overview of the biological characteristics of AAV vectors and the therapeutic advancements observed in preclinical models of ischemic stroke. The study further investigates the potential of manipulating AAV vectors in preclinical applications, emphasizing the challenges and prospects in the selection of viral vectors, drug delivery strategies, immune reactions, and clinical translation.

Integrated gene expression profiling and functional enrichment analyses to discover biomarkers and pathways associated with Guillain-Barré syndrome and autism spectrum disorder to identify new therapeutic targets

Guillain-Barré syndrome (GBS) is one of the most prominent and acute immune-mediated peripheral neuropathy, while autism spectrum disorders (ASD) are a group of heterogeneous neurodevelopmental disorders. The complete mechanism regarding the neuropathophysiology of these disorders is still ambiguous. Even after recent breakthroughs in molecular biology, the link between GBS and ASD remains a mystery. Therefore, we have implemented well-established bioinformatic techniques to identify potential biomarkers and drug candidates for GBS and ASD. 17 common differentially expressed genes (DEGs) were identified for these two disorders, which later guided the rest of the research. Common genes identified the protein-protein interaction (PPI) network and pathways associated with both disorders. Based on the PPI network, the constructed hub gene and module analysis network determined two common DEGs, namely CXCL9 and CXCL10, which are vital in predicting the top drug candidates. Furthermore, coregulatory networks of TF-gene and TF-miRNA were built to detect the regulatory biomolecules. Among drug candidates, imatinib had the highest docking and MM-GBSA score with the well-known chemokine receptor CXCR3 and remained stable during the 100 ns molecular dynamics simulation validated by the principal component analysis and the dynamic cross-correlation map. This study predicted the gene-based disease network for GBS and ASD and suggested prospective drug candidates. However, more in-depth research is required for clinical validation.Communicated by Ramaswamy H. Sarma.

The DST gene in neurobiology

DST is a gene whose alternative splicing yields epithelial, neuronal, and muscular isoforms. The autosomal recessive Dstdt (dystonia musculorum) spontaneous mouse mutation causes degeneration of spinocerebellar tracts as well as peripheral sensory nerves, dorsal root ganglia, and cranial nerve ganglia. In addition to Dstdt mutants, axonopathy and neurofilament accumulation in perikarya are features of two other murine lines with spontaneous Dst mutations, targeted Dst knockout mice, DstTg4 transgenic mice carrying two deleted Dst exons, DstGt mice with trapped actin-binding domain-containing isoforms, and conditional Schwann cell-specific Dst knockout mice. As a result of nerve damage, Dstdt mutants display dystonia and ataxia, as seen in several genetically modified models and their motor coordination deficits have been quantified along with the spontaneous Dst nonsense mutant, the conditional Schwann cell-specific Dst knockout, the conditional DstGt mutant, and the Dst-b isoform specific Dst mutant. Recent findings in humans have associated DST mutations of the Dst-b isoform with hereditary sensory and autonomic neuropathies type 6 (HSAN-VI). These data should further encourage the development of genetic techniques to treat or prevent ataxic and dystonic symptoms.

An Overview of the Therapeutic Strategies for the Treatment of Spinal Muscular Atrophy

Spinal muscular atrophy (SMA) is a recessive, neurodegenerative disorder. It is one of the most common genetic causes of infant mortality and is characterized by muscle weakness, loss of ambulation, and respiratory failure. SMA is primarily caused by a homozygous deletion or mutation of the survival motor neuron 1 (SMN1) gene. Humans possess a second, nearly identical copy of SMN, known as the SMN2 gene. Although the disease severity correlates inversely with the number of SMN2 copies present, it can never completely compensate for the loss of SMN1 in patients with SMA; SMN2 expresses only a fraction of the functional SMN transcript. The SMN protein is ubiquitous in human cells and plays several roles, ranging from assembling the spliceosome machinery to autophagy, RNA metabolism, signal transduction, cellular homeostasis, DNA repair, and recombination. Although the underlying mechanism remains unclear, anterior horn cells of the spinal cord gray matter are highly vulnerable to decreased SMN protein levels. To harness SMN2's ability to provide SMN function, two treatment strategies have been approved by the Food and Drug Administration (FDA), including an antisense oligonucleotide, nusinersen (Spinraza), and a small molecule, risdiplam (Evrysdi). Onasemnogene abeparvovec (Zolgensma) is an FDA-approved adeno-associated virus 9-mediated gene replacement therapy that creates a copy of the human SMN1 gene. In this review, we summarize the SMA etiology and FDA-approved therapies, and discuss the development of SMA therapeutic strategies and the challenges we faced.

Long Non-Coding RNAs in Retinal Ganglion Cell Apoptosis

Traumatic optic neuropathy or other neurodegenerative diseases, including optic nerve transection, glaucoma, and diabetic retinopathy, can lead to progressive and irreversible visual damage. Long non-coding RNAs (lncRNAs), which belong to the family of non-protein-coding transcripts, have been linked to the pathogenesis, progression, and prognosis of these lesions. Retinal ganglion cells (RGCs) are critical for the transmission of visual information to the brain, damage to which results in visual loss. Apoptosis has been identified as one of the most essential modes of RGC death. Emerging evidence suggests that lncRNAs can regulate RGC degeneration by directly or indirectly modulating apoptosis-associated signaling pathways. This review presents a comprehensive overview of the role of lncRNAs in RGC apoptosis at transcriptional, post-transcriptional, translational, and post-translational levels, emphasizing on the potential mechanisms of action. The current limitations and future perspectives of exploring the connection between lncRNAs and RGC apoptosis have been summarized. Understanding the intricate molecular interaction network of lncRNAs and RGC apoptosis will open new avenues for the identification of novel diagnostic biomarkers, therapeutic targets, and molecules for prognostic evaluation of diseases related to RGC injury.

KIF1A-Associated Neurological Disorder: An Overview of a Rare Mutational Disease

KIF1A-associated neurological diseases (KANDs) are a group of inherited conditions caused by changes in the microtubule (MT) motor protein KIF1A as a result of KIF1A gene mutations. Anterograde transport of membrane organelles is facilitated by the kinesin family protein encoded by the MT-based motor gene KIF1A. Variations in the KIF1A gene, which primarily affect the motor domain, disrupt its ability to transport synaptic vesicles containing synaptophysin and synaptotagmin leading to various neurological pathologies such as hereditary sensory neuropathy, autosomal dominant and recessive forms of spastic paraplegia, and different neurological conditions. These mutations are frequently misdiagnosed because they result from spontaneous, non-inherited genomic alterations. Whole-exome sequencing (WES), a cutting-edge method, assists neurologists in diagnosing the illness and in planning and choosing the best course of action. These conditions are simple to be identified in pediatric and have a life expectancy of 5-7 years. There is presently no permanent treatment for these illnesses, and researchers have not yet discovered a medicine to treat them. Scientists have more hope in gene therapy since it can be used to cure diseases brought on by mutations. In this review article, we discussed some of the experimental gene therapy methods, including gene replacement, gene knockdown, symptomatic gene therapy, and cell suicide gene therapy. It also covered its clinical symptoms, pathogenesis, current diagnostics, therapy, and research advances currently occurring in the field of KAND-related disorders. This review also explained the impact that gene therapy can be designed in this direction and afford the remarkable benefits to the patients and society.

Nanoparticle Mediated Gene Therapy: A Trailblazer Armament to Fight CNS Disorders

Central nervous system (CNS) disorders account for boundless socioeconomic burdens with devastating effects among the population, especially the elderly. The major symptoms of these disorders are neurodegeneration, neuroinflammation, and cognitive dysfunction caused by inherited genetic mutations or by genetic and epigenetic changes due to injury, environmental factors, and disease-related events. Currently available clinical treatments for CNS diseases, i.e., Alzheimer's disease, Parkinson's disease, stroke, and brain tumor, have significant side effects and are largely unable to halt the clinical progression. So gene therapy displays a new paradigm in the treatment of these disorders with some modalities, varying from the suppression of endogenous genes to the expression of exogenous genes. Both viral and non-viral vectors are commonly used for gene therapy. Viral vectors are quite effective but associated with severe side effects, like immunogenicity and carcinogenicity, and poor target cell specificity. Thus, non-viral vectors, mainly nanotherapeutics like nanoparticles (NPs), turn out to be a realistic approach in gene therapy, achieving higher efficacy. NPs demonstrate a new avenue in pharmacotherapy for the delivery of drugs or genes to their selective cells or tissue, thus providing concentrated and constant drug delivery to targeted tissues, minimizing systemic toxicity and side effects. The current review will emphasize the role of NPs in mediating gene therapy for CNS disorders treatment. Moreover, the challenges and perspectives of NPs in gene therapy will be summarized.

The relationships between neuroglial and neuronal changes in Alzheimer's disease, and the related controversies II:

Since the original description of Alzheimer´s disease (AD), research into this condition has mainly focused on assessing the alterations to neurons associated with dementia, and those to the circuits in which they are involved. In most of the studies on human brains and in many models of AD, the glial cells accompanying these neurons undergo concomitant alterations that aggravate the course of neurodegeneration. As a result, these changes to neuroglial cells are now included in all the "pathogenic cascades" described in AD. Accordingly, astrogliosis and microgliosis, the main components of neuroinflammation, have been integrated into all the pathogenic theories of this disease, as discussed in this part of the two-part monograph that follows an accompanying article on gliopathogenesis and glioprotection. This initial reflection verified the implication of alterations to the neuroglia in AD, suggesting that these cells may also represent therapeutic targets to prevent neurodegeneration. In this second part of the monograph, we will analyze the possibilities of acting on glial cells to prevent or treat the neurodegeneration that is the hallmark of AD and other pathologies. Evidence of the potential of different pharmacological, non-pharmacological, cell and gene therapies (widely treated) to prevent or treat this disease is now forthcoming, in most cases as adjuncts to other therapies. A comprehensive AD multimodal therapy is proposed in which neuronal and neuroglial pharmacological treatments are jointly considered, as well as the use of new cell and gene therapies and non-pharmacological therapies that tend to slow down the progress of dementia.

Lentivirus- or AAV-mediated gene therapy interventions in ischemic stroke: A systematic review of preclinical in vivo studies

Due to the limited therapeutic options after ischemic stroke, gene therapy has emerged as a promising choice, especially with recent advances in viral vector delivery systems. Therefore, we aimed to provide the current state of the art of lentivirus (LV) and adeno-associated virus (AAV) mediated gene interventions in preclinical ischemic stroke models. A systematic analysis including qualitative and quantitative syntheses of studies published until December 2020 was performed. Most of the 87 selected publications used adult male rodents and the preferred stroke model was transient middle cerebral artery occlusion. LV and AAV vectors were equally used for transgene delivery, however loads of AAVs were higher than LVs. Serotypes having broad cell tropism, the use of constitutive promoters, and virus delivery before the stroke induction via stereotaxic injection in the cortex and striatum were preferred in the analyzed studies. The meta-analysis based on infarct volume as the primary outcome confirmed the efficacy of the preclinical interventions. The quality assessment exposed publication bias and setbacks in regard to risks of bias and study relevance. The translational potential could increase by using specific cell targeting, post-stroke interventions, non-invasive systematic delivery, and use of large animals.

Gene editing and its applications in biomedicine

The steady progress in genome editing, especially genome editing based on the use of clustered regularly interspaced short palindromic repeats (CRISPR) and programmable nucleases to make precise modifications to genetic material, has provided enormous opportunities to advance biomedical research and promote human health. The application of these technologies in basic biomedical research has yielded significant advances in identifying and studying key molecular targets relevant to human diseases and their treatment. The clinical translation of genome editing techniques offers unprecedented biomedical engineering capabilities in the diagnosis, prevention, and treatment of disease or disability. Here, we provide a general summary of emerging biomedical applications of genome editing, including open challenges. We also summarize the tools of genome editing and the insights derived from their applications, hoping to accelerate new discoveries and therapies in biomedicine.

Gene Therapy Strategy for Alzheimer's and Parkinson's Diseases Aimed at Preventing the Formation of Neurotoxic Oligomers in SH-SY5Y Cells

We present here a gene therapy approach aimed at preventing the formation of Ca2+-permeable amyloid pore oligomers that are considered as the most neurotoxic structures in both Alzheimer's and Parkinson's diseases. Our study is based on the design of a small peptide inhibitor (AmyP53) that combines the ganglioside recognition properties of the β-amyloid peptide (Aβ, Alzheimer) and α-synuclein (α-syn, Parkinson). As gangliosides mediate the initial binding step of these amyloid proteins to lipid rafts of the brain cell membranes, AmyP53 blocks, at the earliest step, the Ca2+ cascade that leads to neurodegeneration. Using a lentivirus vector, we genetically modified brain cells to express the therapeutic coding sequence of AmyP53 in a secreted form, rendering these cells totally resistant to oligomer formation by either Aβ or α-syn. This protection was specific, as control mCherry-transfected cells remained fully sensitive to these oligomers. AmyP53 was secreted at therapeutic concentrations in the supernatant of cultured cells, so that the therapy was effective for both transfected cells and their neighbors. This study is the first to demonstrate that a unique gene therapy approach aimed at preventing the formation of neurotoxic oligomers by targeting brain gangliosides may be considered for the treatment of two major neurodegenerative disorders, Alzheimer's and Parkinson's diseases.

Effect of silencing C-erbB-2 on esophageal carcinoma cell biological behaviors by inhibiting IGF-1 pathway activation

OBJECTIVE

C-erbB-2 has been confirmed to be an oncogene that participates in cell growth, differentiation and division of tumors. We are wondered if its silenced expression can exert an anti-tumor effect. Therefore, this study is conducted to investigate the mechanism of C-erbB-2 silencing and IGF-1 pathway on esophageal carcinoma (EC) cell biological behaviors.

METHODS

The objects of study were 84 EC patients from Heping Hospital Affiliated to Changzhi Medical College, with the collection of EC tissue and adjacent normal tissue (> 5 cm away from cancer tissue). C-erbB-2 protein expression in EC tissues was detected by immunohistochemistry. Human EC cell line Eca-109 was purchased from Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences. Based on different transfection protocols, EC cells with logarithmic growth phase of 3-5 passages were divided into blank control group, oe-C-erbB-2 NC group, siRNA C-erbB-2 NC group, oe-C-erbB-2 group, siRNA C-erbB-2 group, OSI-906 group, Rg5 group, Rg5 + siRNA C-erbB-2 NC group and Rg5 + siRNA C-erbB-2 group. Cell proliferation was detected by MTT assay; cell cycle distribution and apoptosis by flow cytometry; C-erbB-2, IGF-1, IGF-1R and Akt mRNA and protein expressions by qRT-PCR and western blot; and cell invasion and migration by Transwell assay and scratch test. Tumor growth was observed in male BALB/c nude mice (Shanghai Experimental Animal Center) based on Eca109 cell implantation, raising, and measurement.

RESULTS

C-erbB-2, IGF-1, IGF-1R and Akt expression were higher in EC tissues than those in adjacent tissues (all P < 0.05). Compared with blank control group, both si-C-erbB-2 and OSI-906 groups had decreased IGF-1, IGF-1R and Akt mRNA and protein expressions, decreased cell proliferation, migration and invasion, prolonged G0/G1 phase, shortened S phase, increased cell apoptosis, and inhibited tumor growth (all P < 0.05); while opposite trends were detected in C-erbB-2 vector and Rg5 groups (all P < 0.05), without statistical differences in siRNA C-erbB-2 + Rg5 group (all P > 0.05).

CONCLUSION

Silencing C-erbB-2 expression may inhibit EC cell proliferation, promote cell apoptosis and block cell cycle progression by inhibiting IGF-1 pathway activation. The beneficial effect of silencing C-erbB-2 expression can be reversed by promoting the activation of IGF-1 pathway. Findings in our study may provide potential reference for understanding the molecular mechanism of EC and supply possible axis for preventing the development of EC from the perspective of molecular biology.

Neurorepair and Regeneration of the Brain: A Decade of Bioscaffolds and Engineered Microtissue

Repairing the human brain remains a challenge, despite the advances in the knowledge of inflammatory response to injuries and the discovery of adult neurogenesis. After brain injury, the hostile microenvironment and the lack of structural support for neural cell repopulation, anchoring, and synapse formation reduce successful repair chances. In the past decade, we witnessed the rise of studies regarding bioscaffolds’ use as support for neuro repair. A variety of natural and synthetic materials is available and have been used to replace damaged tissue. Bioscaffolds can assume different shapes and may or may not carry a diversity of content, such as stem cells, growth factors, exosomes, and si/miRNA that promote specific therapeutic effects and stimulate brain repair. The use of these external bioscaffolds and the creation of cell platforms provide the basis for tissue engineering. More recently, researchers were able to engineer brain organoids, neural networks, and even 3D printed neural tissue. The challenge in neural tissue engineering remains in the fabrication of scaffolds with precisely controlled topography and biochemical cues capable of directing and controlling neuronal cell fate. The purpose of this review is to highlight the existing research in the growing field of bioscaffolds’ development and neural tissue engineering. Moreover, this review also draws attention to emerging possibilities and prospects in this field.

BBB-crossing adeno-associated virus vector: An excellent gene delivery tool for CNS disease treatment

The presence of the blood-brain barrier (BBB) remains a challenge in the treatment of central nervous system (CNS) diseases, as it hinders the infiltration of many therapeutic drugs into the brain parenchyma. Therefore, developing efficacious pharmacological agents that can traverse the BBB is crucial for optimal treatment of diseases of the CNS such as neurodegenerative conditions and brain tumors. Adeno-associated virus (AAV), one of the most promising gene therapy vectors, has been shown to cross the BBB safely and is non-pathogenic in nature and therefore has been utilized for numerous diseases of the CNS. Along with the development of protein engineering techniques such as directed evolution including DNA shuffling, a great number of BBB-crossing AAVs have been developed, that could be systemically injected for therapeutic benefit. In this review, we discuss several feasible approaches to improve transportation of therapeutic agents to the CNS. We also discuss the advantages of using BBB-crossing AAVs, their role as a gene delivery agent and highlight the different types of BBB-AAV vectors that have been developed in order to provide a greater insight into how they can be used in diseases of the CNS.

Exploring the Role of Gene Therapy for Neurological Disorders

Gene therapy is one of the frontier fields of medical breakthroughs that poses as an effective solution to previously incurable diseases. The delivery of the corrective genetic material or a therapeutic gene into the cell restores the missing gene function and cures a plethora of diseases, incurable by the conventional medical approaches. This discovery holds the potential to treat many neurodegenerative disorders such as muscular atrophy, multiple sclerosis, Parkinson's disease (PD) and Alzheimer's disease (AD), among others. Gene therapy proves as a humane, cost-effective alternative to the exhaustive often arduous and timely impossible process of finding matched donors and extensive surgery. It also overcomes the shortcoming of conventional methods to cross the blood-brain barrier. However, the use of gene therapy is only possible after procuring the in-depth knowledge of the immuno-pathogenesis and molecular mechanism of the disease. The process of gene therapy can be broadly categorized into three main steps: elucidating the target gene, culling the appropriate vector, and determining the best mode of transfer; each step mandating pervasive research. This review aims to dissertate and summarize the role, various vectors and methods of delivery employed in gene therapy with special emphasis on therapy directed at the central nervous system (CNS) associated with neurodegenerative diseases.

Challenges in adeno-associated virus-based treatment of central nervous system diseases through systemic injection

Adeno-associated virus (AAV) vector, an excellent gene therapy vector, has been widely used in the treatment of various central nervous system (CNS) diseases. Due to the presence of the blood-brain barrier (BBB), early attempts at AAV-based CNS diseases treatment were mainly performed through intracranial injections. Subsequently, systemic injections of AAV9, the first AAV that was shown to have BBB-crossing ability in newborn and adult mice, were assessed in clinical trials for multiple CNS diseases. However, the development of systemic AAV injections to treat CNS diseases is still associated with many challenges, such as the efficiency of AAV in crossing the BBB, the peripheral toxicity caused by the expression of AAV-delivered genes, and the immune barrier against AAV in the blood. In this review, we will introduce the biology of the AAV vector and the advantages of systemic AAV injections to treat CNS diseases. Most importantly, we will introduce the challenges associated with systemic injection of therapeutic AAV in treating CNS diseases and suggest feasible solutions.

Beyond the Traditional Clinical Trials for Amyotrophic Lateral Sclerosis and The Future Impact of Gene Therapy

Amyotrophic lateral sclerosis (ALS) is a devastating and incurable motor neuron (MN) disorder affecting both upper and lower MNs. Despite impressive advances in the understanding of the disease’s pathological mechanism, classical pharmacological clinical trials failed to provide an efficient cure for ALS over the past twenty years. Two different gene therapy approaches were recently approved for the monogenic disease Spinal muscular atrophy, characterized by degeneration of lower MNs. This milestone suggests that gene therapy-based therapeutic solutions could be effective for the treatment of ALS. This review summarizes the possible reasons for the failure of traditional clinical trials for ALS. It provides then a focus on the advent of gene therapy approaches for hereditary forms of ALS. Specifically, it describes clinical use of antisense oligonucleotides in three familial forms of ALS, caused by mutations in SOD1, C9orf72 and FUS genes, respectively.. Clinical and pre-clinical studies based on AAV-mediated gene therapy approaches for both familial and sporadic ALS cases are presented as well. Overall, this overview highlights the potential of gene therapy as a transforming technology that will have a huge impact on treatment perspective for ALS patients and on the design of future clinical trials.

Current Status and Challenges Associated with CNS-Targeted Gene Delivery across the BBB

The era of the aging society has arrived, and this is accompanied by an increase in the absolute numbers of patients with neurological disorders, such as Alzheimer’s disease (AD) and Parkinson’s disease (PD). Such neurological disorders are serious costly diseases that have a significant impact on society, both globally and socially. Gene therapy has great promise for the treatment of neurological disorders, but only a few gene therapy drugs are currently available. Delivery to the brain is the biggest hurdle in developing new drugs for the central nervous system (CNS) diseases and this is especially true in the case of gene delivery. Nanotechnologies such as viral and non-viral vectors allow efficient brain-targeted gene delivery systems to be created. The purpose of this review is to provide a comprehensive review of the current status of the development of successful drug delivery to the CNS for the treatment of CNS-related disorders especially by gene therapy. We mainly address three aspects of this situation: (1) blood-brain barrier (BBB) functions; (2) adeno-associated viral (AAV) vectors, currently the most advanced gene delivery vector; (3) non-viral brain targeting by non-invasive methods.

The Role of Chronic Inflammatory Bone and Joint Disorders in the Pathogenesis and Progression of Alzheimer's Disease

Late-onset Alzheimer's Disease (LOAD) is a devastating neurodegenerative disorder that causes significant cognitive debilitation in tens of millions of patients worldwide. Throughout disease progression, abnormal secretase activity results in the aberrant cleavage and subsequent aggregation of neurotoxic Aβ plaques in the cerebral extracellular space and hyperphosphorylation and destabilization of structural tau proteins surrounding neuronal microtubules. Both pathologies ultimately incite the propagation of a disease-associated subset of microglia-the principle immune cells of the brain-characterized by preferentially pro-inflammatory cytokine secretion and inhibited AD substrate uptake capacity, which further contribute to neuronal degeneration. For decades, chronic neuroinflammation has been identified as one of the cardinal pathophysiological driving features of AD; however, despite a number of works postulating the underlying mechanisms of inflammation-mediated neurodegeneration, its pathogenesis and relation to the inception of cognitive impairment remain obscure. Moreover, the limited clinical success of treatments targeting specific pathological features in the central nervous system (CNS) illustrates the need to investigate alternative, more holistic approaches for ameliorating AD outcomes. Accumulating evidence suggests significant interplay between peripheral immune activity and blood-brain barrier permeability, microglial activation and proliferation, and AD-related cognitive decline. In this work, we review a narrow but significant subset of chronic peripheral inflammatory conditions, describe how these pathologies are associated with the preponderance of neuroinflammation, and posit that we may exploit peripheral immune processes to design interventional, preventative therapies for LOAD. We then provide a comprehensive overview of notable treatment paradigms that have demonstrated considerable merit toward treating these disorders.

Mesenchymal stem cells as a multimodal treatment for nervous system diseases

Neurological disorders are a massive challenge for modern medicine. Apart from the fact that this group of diseases is the second leading cause of death worldwide, the majority of patients have no access to any possible effective and standardized treatment after being diagnosed, leaving them and their families helpless. This is the reason why such great emphasis is being placed on the development of new, more effective methods to treat neurological patients. Regenerative medicine opens new therapeutic approaches in neurology, including the use of cell-based therapies. In this review, we focus on summarizing one of the cell sources that can be applied as a multimodal treatment tool to overcome the complex issue of neurodegeneration-mesenchymal stem cells (MSCs). Apart from the highly proven safety of this approach, beneficial effects connected to this type of treatment have been observed. This review presents modes of action of MSCs, explained on the basis of data from vast in vitro and preclinical studies, and we summarize the effects of using these cells in clinical trial settings. Finally, we stress what improvements have already been made to clarify the exact mechanism of MSCs action, and we discuss potential ways to improve the introduction of MSC-based therapies in clinics. In summary, we propose that more insightful and methodical optimization, by combining careful preparation and administration, can enable use of multimodal MSCs as an effective, tailored cell therapy suited to specific neurological disorders.

Gene therapies for high-grade gliomas: from the bench to the bedside

Background:

Gene therapy is the most attractive therapeutic approach against high-grade gliomas (HGGs). This is because of its theoretical capability to rework gene makeup in order to yield oncolytic effects. However, some factors still limit the upgrade of these therapies at a clinical level of evidence. We report an overview of glioblastoma gene therapies, mainly focused on the rationale, classification, advances and translational challenges.

Methods:

An extensive review of the online literature on gene therapy for HGGs was carried out. The PubMed/MEDLINE and ClinicalTrials.gov websites were the main sources. Articles in English published in the last five years were sorted according to the best match with the multiple relevant keywords chosen. A descriptive analysis of the clinical trials was also reported.

Results:

A total of 85 articles and 45 clinical trials were selected. The main types of gene therapies are the suicide gene, tumor suppressor gene, immunomodulatory gene and oncolytic therapies (virotherapies). The transfer of genetic material entails replication-deficient and replication-competent oncolytic viruses and nanoparticles, such as liposomes and cationic polymers, each of them having advantages and drawbacks. Forty-eight clinical trials were collected, mostly phase I/II.

Conclusion:

Gene therapies constitute a promising approach against HGGs. The selection of new and more effective target genes, the implementation of gene-delivery vectors capable of greater and safer spreading capacity, and the optimization of the administration routes constitute the main translational challenges of this approach. (www.actabiomedica.it)

Intellectual Disability and Potassium Channelopathies: A Systematic Review

Intellectual disability (ID) manifests prior to adulthood as severe limitations to intellectual function and adaptive behavior. The role of potassium channelopathies in ID is poorly understood. Therefore, we aimed to evaluate the relationship between ID and potassium channelopathies. We hypothesized that potassium channelopathies are strongly associated with ID initiation, and that both gain- and loss-of-function mutations lead to ID. This systematic review explores the burden of potassium channelopathies, possible mechanisms, advancements using animal models, therapies, and existing gaps. The literature search encompassed both PubMed and Embase up to October 2019. A total of 75 articles describing 338 cases were included in this review. Nineteen channelopathies were identified, affecting the following genes: KCNMA1, KCNN3, KCNT1, KCNT2, KCNJ10, KCNJ6, KCNJ11, KCNA2, KCNA4, KCND3, KCNH1, KCNQ2, KCNAB1, KCNQ3, KCNQ5, KCNC1, KCNB1, KCNC3, and KCTD3. Twelve of these genes presented both gain- and loss-of-function properties, three displayed gain-of-function only, three exhibited loss-of-function only, and one had unknown function. How gain- and loss-of-function mutations can both lead to ID remains largely unknown. We identified only a few animal studies that focused on the mechanisms of ID in relation to potassium channelopathies and some of the few available therapeutic options (channel openers or blockers) appear to offer limited efficacy. In conclusion, potassium channelopathies contribute to the initiation of ID in several instances and this review provides a comprehensive overview of which molecular players are involved in some of the most prominent disease phenotypes.

Nanoparticle Based Gene Therapy Approach: A Pioneering Rebellion in the Management of Psychiatric Disorders

The neuropsychiatric illnesses have been enigmatic, with no effective treatment to date. The complexity and heterogeneity of psychiatric disorders are daunting for the development of novel treatment modalities. The conventional treatment approaches are less effective and are associated with several side effects, thus creating the need for the development of more innovative strategies. Since psychiatric disorders are known to exhibit genetic linkage, gene therapy has created an interest among the researchers worldwide. The delivery of nucleic acids is a complex process requiring the transport of genetic material across various intracellular and extracellular barriers to reach the target cells eliciting the transfection process. Therefore, the identification or development of the delivery system for nucleic acid delivery still remains the challenge. Viral vectors are quite effective but are associated with toxicity and side effects. With the rapid advancement in the field of nanotechnology, nanosized materials were identified to be the perfect candidate for nonviral vectors in gene delivery. The biggest advantage of nanoparticles is that their surface can be engineered in many possible ways to deliver the drugs directly to the target site. Although gene therapy has already been established as an innovative treatment modality for several neurological diseases, its use in psychiatry still warrants more investigations for its translation into clinical use. The present manuscript discusses the prospects of gene therapy in psychiatric disorders, their benefits, and pitfalls. The review embarks upon the importance of nanoparticle-based gene therapy for effective management of psychiatric disorders.

Enhanced Production of Herpes Simplex Virus 1 Amplicon Vectors by Gene Modification and Optimization of Packaging Cell Growth Medium

Herpes simplex virus 1 (HSV-1)-derived amplicon vectors are unique in their ability to accommodate large DNA molecules allowing whole genomic loci to be included with all of their regulatory elements. Additional advantages of these amplicons include their minimal toxicity and ability to persist as episomes, with negligible risk of insertional mutagenesis, being particularly well-suited for gene therapy of neurological disorders due to their outstanding ability to deliver genes into neurons and other neural cells. However, extensive gene therapy application has been hindered by difficulties in vector production. This work improved HSV-1 amplicons production by genetic modification of the packaging cell line and optimization of the culture medium. A stably-transfected Vero 2-2 cell line overexpressing the anti-apoptotic Bcl-2 protein was generated, exhibiting an increased resistance to apoptosis, prolonged culture duration, and a significant improvement in viral vector production. Additionally, supplementation of the growth medium with antioxidants, polyamines, amino acids, and reduced glutathione further increased the yield of packaged amplicon vectors. With these modifications, HSV-1 amplicons could be isolated from culture supernatants instead of cell lysates, leading to vector preparations with higher titer and purity and paving the way for generation of stable cell lines that are capable of continuous herpesviral vector production.

Gene therapy to the blood-brain barrier with resulting protein secretion as a strategy for treatment of Niemann Picks type C2 disease

Treatment of many diseases affecting the central nervous system (CNS) is complicated by the inability of several therapeutics to cross the blood-brain barrier (BBB). Genetically modifying brain capillary endothelial cells (BCECs) denotes an approach to overcome the limitations of the BBB by turning BCECs into recombinant protein factories. This will result in protein secretion toward both the brain and peripheral circulation, which is particularly relevant in genetic diseases, like lysosomal storage diseases (LSD), where cells are ubiquitously affected both in the CNS and the periphery. Here we investigated transfection of primary rat brain capillary endothelial cells (rBCECs) for synthesis and secretion of recombinant NPC2, the protein deficient in the lysosomal cholesterol storage disease Niemann Pick type C2. We demonstrate prominent NPC2 gene induction and protein secretion in 21% of BCECs in non-mitotic monocultures with a biological effect on NPC2-deficient fibroblasts as verified from changes in filipin III staining of cholesterol deposits. By comparison the transfection efficiency was 75% in HeLa-cells, known to persist in a mitotic state. When co-cultured with primary rat astrocytes in conditions with maintained BBB properties 7% BCECs were transfected, clearly suggesting that induction of BBB properties with polarized conditions of the non-mitotic BCECs influences the transfection efficacy and secretion directionality. In conclusion, non-viral gene therapy to rBCECs leads to protein secretion and signifies a method for NPC2 to target cells inside the CNS otherwise inaccessible because of the presence of the BBB. However, obtaining high transfection efficiencies is crucial in order to achieve sufficient therapeutic effects. Cover Image for this issue: https://doi.org/10.1111/jnc.15050.

The cell-based approach in neurosurgery: ongoing trends and future perspectives

OBJECTIVE

Examination of the current trends and future perspectives of the cell-based therapies in neurosurgery.

METHODS

A PubMed/MEDLINE-based systematic review has been performed combining the main Medical Subject Headings (MeSH) regarding the cell- and tissue-based therapies with the "Brain", "Spinal Cord", "Spine" and "Skull" MeSH terms. Only articles in English published in the last 10 years and pertinent to neurosurgery have been selected.

RESULTS

A total of 1,173 relevant articles have been chosen. Somatic cells and gene-modification technologies have undergone the greatest development. Immunotherapies and gene therapies have been tested for the cure of glioblastoma, stem cells mainly for brain and spinal cord traumatic injuries. Stem cells have also found a rationale in the treatment of the cranial and spinal bony defects, and of the intervertebral disc degeneration, as well.Most of the completed or ongoing trials concerning the cell-based therapies in neurosurgery are on phase 2. Future perspectives involve the need to overcome issues related to immunogenicity, oncogenicity and routes for administration. Refinement and improvement of vector design and delivery are required within the gene therapies.

CONCLUSION

The last decade has been characterised by a progressive evolution of neurosurgery from a purely mechanical phase to a new biological one. This trend has followed the rapid and parallel development of translational medicine and nanotechnologies.The introduction of new technologies, the optimisation of the already existing ones, and the reduction of costs are among the main challenges of the foreseeable future.

Gene Therapy for ALS-A Perspective

Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron disease (MND) with no cure. Recent advances in gene therapy open a new perspective to treat this disorder-particularly for the characterized genetic forms. Gene therapy approaches, involving the delivery of antisense oligonucleotides into the central nervous system (CNS) are being tested in clinical trials for patients with mutations in SOD1 or C9orf72 genes. Viral vectors can be used to deliver therapeutic sequences to stably transduce motor neurons in the CNS. Vectors derived from adeno-associated virus (AAV), can efficiently target genes and have been tested in several pre-clinical settings with promising outcomes. Recently, the Food and Drug Administration (FDA) approved Zolgensma, an AAV-mediated treatment for another MND-the infant form of spinal muscular atrophy. Given the accelerated progress in gene therapy, it is potentially a promising avenue to develop an efficient and safe cure for ALS.

Acupuncture protects from 6-OHDA-induced neuronal damage by balancing the ratio of DMT1/Fpn1

Objective

Acupuncture is a commonly used method to provide motor-symptomatic relief for patients with Parkinson s disease (PD). Our objective was to evaluate protective effects of acupuncture treatment and potential underlying mechanisms according to the “gut-brain axis” theory.

Methods

We employed a 6-OHDA-induced PD rat model. The effects of acupuncture on disease development were assessed by behavioural tests and immunohistochistry (IHC). ELISA, qPCR and western blot (WB) were employed to measure inflammatory parameters and Fe metabolism in the substantia nigra (SN), striatum, duodenum and blood, respectively.

Results

Our data show that acupuncture can significantly increase the expression of tyrosine hydroxylase (TH), compared with untreated and madopa treated rats (P < 0.01 and P < 0.05, respectively). Furthermore we could observe significantly decreased levels of pro-inflammatory markers in the duodenum and serum (P < 0.05), reduced deposition of Fe in the substantia nigra (P < 0.05) and but no change in transferrin expression after acupuncture treatment. The mRNA ratio of DMT1/Fpn1 in the SN of acupuncture treated rats (1.1) was comparable to that of the sham group (1.0) which differed both significantly from the untreated and madopa treated groups (P < 0.05). Furthermore, after acupuncture expression of α-synuclein was decreased in the duodenum.

Conclusions

Acupuncture can reduce iron accumulation in the SN and protect the loss of dopamine neurons by promoting balanced expression of the iron importer DMT1 and the iron exporter Fpn1. Furthermore CNS iron homeostasis may be affected by reduced systemic and intestinal inflammation.

Small interfering RNA delivery to the neurons near the amyloid plaques for improved treatment of Alzheimer׳s disease

Gene therapy represents a promising treatment for the Alzheimer׳s disease (AD). However, gene delivery specific to brain lesions through systemic administration remains big challenge. In our previous work, we have developed an siRNA nanocomplex able to be specifically delivered to the amyloid plaques through surface modification with both CGN peptide for the blood–brain barrier (BBB) penetration and QSH peptide for β-amyloid binding. But, whether the as-designed nanocomplex could indeed improve the gene accumulation in the impaired neuron cells and ameliorate AD-associated symptoms remains further study. Herein, we prepared the nanocomplexes with an siRNA against β-site amyloid precursor protein-cleaving enzyme 1 (BACE1), the rate-limiting enzyme of Aβ production, as the therapeutic siRNA of AD. The nanocomplexes exhibited high distribution in the Aβ deposits-enriched hippocampus, especially in the neurons near the amyloid plaques after intravenous administration. In APP/PS1 transgenic mice, the nanocomplexes down-regulated BACE1 in both mRNA and protein levels, as well as Aβ and amyloid plaques to the level of wild-type mice. Moreover, the nanocomplexes significantly increased the level of synaptophysin and rescued memory loss of the AD transgenic mice without hematological or histological toxicity. Taken together, this work presented direct evidences that the design of precise gene delivery to the AD lesions markedly improves the therapeutic outcome.

Modulation of mTOR and CREB pathways following mGluR5 blockade contribute to improved Huntington's pathology in zQ175 mice

Huntington’s disease (HD) is a neurodegenerative disorder caused by a genetic abnormality in the huntingtin gene that leads to a polyglutamine repeat expansion of the huntingtin protein. The cleaved polyglutamine expansion of mutant huntingtin (mHTT) protein can form aggregates strongly correlated with HD progression. We have previously shown that the inhibition of mGluR5 using CTEP, a selective negative allosteric mGluR5 modulator, can delay disease progression and reduce in mHTT aggregates in the zQ175 mouse model of HD. This was paralleled by enhanced catalytic activity of Unc-51-like kinase 1 (ULK1), a kinase modulated by mammalian target of rapamycin (mTOR) and key regulator of autophagy initiation. In the present study, we show that CTEP can correct aberrant phosphoinositide 3-kinase (PI3K)/Akt/mTOR signaling detected in zQ175 mice that may underlie the enhanced ULK1 activity and activation of autophagy. We also show that CTEP can facilitate cAMP response element-binding protein (CREB)-mediated expression of brain-derived neurotrophic factor (BDNF) to foster neuronal survival and reduce apoptosis. Taken together, our findings provide the molecular evidence for how targeting mGluR5 using a well-tolerated selective NAM can mitigate two critical mechanisms of neurodegeneration, autophagy and apoptosis.

Nucleic Acid-Based Therapeutics for Parkinson's Disease

Parkinson's disease (PD) is a progressive neurodegenerative disorder that is diagnosed largely on clinical grounds due to characteristic motor manifestations that result from the loss of nigrostriatal dopaminergic neurons. While traditional pharmacological approaches to enhance dopamine levels, such as with L-dopa, can be very effective initially, the chronic use of this dopamine precursor is commonly plagued with motor response complications. Additionally, with advancing disease, non-motor manifestations emerge, including psychosis and dementia that compound patient disability. The pathology includes hallmark intraneuronal inclusions known as Lewy bodies and Lewy neurites that contain fibrillar α-synuclein aggregates. Evidence has also accumulated that these aggregates can propagate across synaptically connected brain regions, a phenomenon that can explain the progressive nature of the disease and the emergence of additional symptoms over time. The level of α-synuclein is believed to play a critical role in its fibrillization and aggregation. Accordingly, nucleic acid-based therapeutics for PD include strategies to deliver dopamine biosynthetic enzymes to boost dopamine production or modulate the basal ganglia circuitry in order to improve motor symptoms. Delivery of trophic factors that might enhance the survival of dopamine neurons is another strategy that has been attempted. These gene therapy approaches utilize viral vectors and are delivered stereotaxically in the brain. Alternative disease-modifying strategies focus on downregulating the expression of the α-synuclein gene using various techniques, including modified antisense oligonucleotides, short hairpin RNA, short interfering RNA, and microRNA. The latter approaches also have implications for dementia with Lewy bodies. Other PD genes can also be targeted using nucleic acids. In this review, we detail these various strategies that are still experimental, and discuss the challenges and opportunities of nucleic acid-based therapeutics for PD.

Emergent Prophylactic, Reparative and Restorative Brain Interventions for Infants Born Preterm With Cerebral Palsy

Worldwide, an estimated 15 million babies are born preterm (<37 weeks' gestation) every year. Despite significant improvements in survival rates, preterm infants often face a lifetime of neurodevelopmental disability including cognitive, behavioral, and motor impairments. Indeed, prematurity remains the largest risk factor for the development of cerebral palsy. The developing brain of the preterm infant is particularly fragile; preterm babies exhibit varying severities of cerebral palsy arising from reductions in both cerebral white and gray matter volumes, as well as altered brain microstructure and connectivity. Current intensive care therapies aim to optimize cardiovascular and respiratory function to protect the brain from injury by preserving oxygenation and blood flow. If a brain injury does occur, definitive diagnosis of cerebral palsy in the first few hours and weeks of life is difficult, especially when the lesions are subtle and not apparent on cranial ultrasound. However, early diagnosis of mildly affected infants is critical, because these are the patients most likely to respond to emergent treatments inducing neuroplasticity via high-intensity motor training programs and regenerative therapies involving stem cells. A current controversy is whether to test universal treatment in all infants at risk of brain injury, accepting that some patients never required treatment, because the perceived potential benefits outweigh the risk of harm. Versus, waiting for a diagnosis before commencing targeted treatment for infants with a brain injury, and potentially missing the therapeutic window. In this review, we discuss the emerging prophylactic, reparative, and restorative brain interventions for infants born preterm, who are at high risk of developing cerebral palsy. We examine the current evidence, considering the timing of the intervention with relation to the proposed mechanism/s of action. Finally, we consider the development of novel markers of preterm brain injury, which will undoubtedly lead to improved diagnostic and prognostic capability, and more accurate instruments to assess the efficacy of emerging interventions for this most vulnerable group of infants.

Proteasome-targeted nanobodies alleviate pathology and functional decline in an α-synuclein-based Parkinson's disease model

Therapeutics designed to target α-synuclein (α-syn) aggregation may be critical in halting the progression of pathology in Parkinson's disease (PD) patients. Nanobodies are single-domain antibody fragments that bind with antibody specificity, but allow readier genetic engineering and delivery. When expressed intracellularly as intrabodies, anti-α-syn nanobodies fused to a proteasome-targeting proline, aspartate or glutamate, serine, and threonine (PEST) motif can modulate monomeric concentrations of target proteins. Here we aimed to validate and compare the in vivo therapeutic potential of gene therapy delivery of two proteasome-directed nanobodies selectively targeting α-syn in a synuclein overexpression-based PD model: VH14*PEST (non-amyloid component region) and NbSyn87*PEST (C-terminal region). Stereotaxic injections of adeno-associated viral 5-α-syn (AAV5-α-syn) into the substantia nigra (SN) were performed in Sprague-Dawley rats that were sorted into three cohorts based on pre-operative behavioral testing. Rats were treated with unilateral SN injections of vectors for VH14*PEST, NbSyn87*PEST, or injected with saline 3 weeks post lesion. Post-mortem assessments of the SN showed that both nanobodies markedly reduced the level of phosphorylated Serine-129 α-syn labeling relative to saline-treated animals. VH14*PEST showed considerable maintenance of striatal dopaminergic tone in comparison to saline-treated and NbSyn87*PEST-treated animals as measured by tyrosine hydroxylase immunoreactivity (optical density), DAT immunoreactivity (optical density), and dopamine concentration (high-performance liquid chromatography). Microglial accumulation and inflammatory response, assessed by stereological counts of Iba-1-labeled cells, was modestly increased in NbSyn87*PEST-injected rats but not in VH14*PEST-treated or saline-treated animals. Modest behavioral rescue was also observed, although there was pronounced variability among individual animals. These data validate in vivo therapeutic efficacy of vector-delivered intracellular nanobodies targeting α-syn misfolding and aggregation in synucleinopathies such as PD.

Photobiomodulation promotes adenoviral gene transduction in auditory cells

Gene therapy is the delivery of a therapeutic gene into target cells to treat disorders by replacing disease-causing mutated genes with healthy ones. Gene therapy of the inner ear has been recently described, with applications for sensorineural hearing loss. However, gene delivery to the location of the inner ear, and thus efficacy of therapy, is challenging. Photobiomodulation (PBM) with a low-level laser has been suggested to have a therapeutic effect and has the potential to augment gene therapy. To investigate whether PBM improves the rate of adenovirus (Ad)-mediated viral delivery, we compared low-level laser therapy (LLLT) and non-LLLT HEI-OC1 cells treated with an Ad viral vector carrying green fluorescent protein (GFP). Cultured HEI-OC1 cells were divided into six groups: no treatment control, LLLT only, 1 μL Ad-GFP, 3 μL Ad-GFP, 1 μL Ad-GFP + LLLT, and 3 μL Ad-GFP + LLLT (LLLT: 808 nm at 15 mW for 15 min). Cells were irradiated twice: at 2 h and again at 24 h. A nonparametric Mann-Whitney U test was used to statistically analyze differences between the control and treatment groups. The viral inoculations used in this study did not change the amount of viable HEI-OC1 cells (N = 4-8). The 1 μL Ad-GFP + LLLT and 3 μL Ad-GFP + LLLT groups showed an increased density of GFP-positive cells compared to 1 μL and 3 μL Ad-GFP cells (N = 5-8, 1 μL: p = 0.0159; 3 μL: p = 0.0168,). The quantitative analysis of the epifluorescence of the 1 μL Ad-GFP + LLLT, and 3 μL Ad-GFP + LLLT groups revealed increased GFP expression/cell compared to 1 μL and 3 μL Ad-GFP cells (N = 6-15, 1 μL: p = 0.0082; 3 μL: p = 0.0012). The RT-qPCR results were consistent (N = 4-5, p = 0.0159). These findings suggest that PBM may enhance the gene delivery of Ad-mediated viral transduction, and the combination of the two may be a promising tool for gene therapy for sensorineural hearing loss.

Have there been improvements in Alzheimer's disease drug discovery over the past 5 years?

INTRODUCTION

Alzheimer's disease (AD) is the most important neurodegenerative disorder with a global cost worldwide of over $700 billion. Pharmacological treatment accounts for 10-20% of direct costs; no new drugs have been approved during the past 15 years; and the available medications are not cost-effective. Areas covered: A massive scrutiny of AD-related PubMed publications (ps)(2013-2017) identified 42,053ps of which 8,380 (19.60%) were associated with AD treatments. The most prevalent pharmacological categories included neurotransmitter enhancers (11.38%), multi-target drugs (2.45%), anti-Amyloid agents (13.30%), anti-Tau agents (2.03%), natural products and derivatives (25.58%), novel drugs (8.13%), novel targets (5.66%), other (old) drugs (11.77%), anti-inflammatory drugs (1.20%), neuroprotective peptides (1.25%), stem cell therapy (1.85%), nanocarriers/nanotherapeutics (1.52%), and others (<1% each). Expert opinion: Unsuccessful outcomes in AD therapeutics are attributed to pathogenic misconceptions, erratic procedures in drug development and inappropriate regulations. Recommendations for the future are as follows: (i) the reconsideration of dominant pathogenic theories, (ii) the identification of reliable biomarkers, (iii) the redefinition of diagnostic criteria, (iv) new guidelines for disease management, (v) the reorientation of drug discovery programs, (vi) the updating of regulatory requirements, (vii) the introduction of pharmacogenomics in drug development and personalized treatments, and (viii) the implementation of preventive programs.

The development of biological therapies for neurological diseases: moving on from previous failures

INTRODUCTION

Although years of research have expanded the use of biologics for several clinical conditions, such development has not yet occurred in the treatment of neurological diseases. With the advancement of biologic technologies, there is promise for these therapeutics as novel therapeutic approaches for neurological diseases. Areas covered: In this article, the authors review the therapeutic potential of different types of biologics for the treatment of neurological diseases. Preclinical and clinical studies that investigate the efficacy and safety of biologics in the treatment of neurological diseases, namely Alzheimer's disease, amyotrophic lateral sclerosis, Parkinson disease, multiple sclerosis, and stroke, were reviewed. Moreover, the authors describe the key challenges in the development of therapeutically safe and effective biologics for the treatment of neurological diseases. Expert opinion: Several biologics have shown promise in the treatment of neurological diseases. However, the complexity of the CNS, as well as a limited understanding of disease progression, and restricted access of biologics to the CNS has limited successful development. Therefore, more research needs to be conducted to overcome these hurdles before developing effective and safe biologics for neurological diseases. The emergence of new technologies for the design, production and delivery of biologics will accelerate translating biologics to the clinic.

Knockdown of the mitochondria-localized protein p13 protects against experimental parkinsonism

Mitochondrial dysfunction in the nigrostriatal dopaminergic system is a critical hallmark of Parkinson's disease (PD). Mitochondrial toxins produce cellular and behavioural dysfunctions resembling those in patients with PD Causative gene products for familial PD play important roles in mitochondrial function. Therefore, targeting proteins that regulate mitochondrial integrity could provide convincing strategies for PD therapeutics. We have recently identified a novel 13-kDa protein (p13) that may be involved in mitochondrial oxidative phosphorylation. In the current study, we examine the mitochondrial function of p13 and its involvement in PD pathogenesis using mitochondrial toxin-induced PD models. We show that p13 overexpression induces mitochondrial dysfunction and apoptosis. p13 knockdown attenuates toxin-induced mitochondrial dysfunction and apoptosis in dopaminergic SH-SY5Y cells via the regulation of complex I. Importantly, we generate p13-deficient mice using the CRISPR/Cas9 system and observe that heterozygous p13 knockout prevents toxin-induced motor deficits and the loss of dopaminergic neurons in the substantia nigra. Taken together, our results suggest that manipulating p13 expression may be a promising avenue for therapeutic intervention in PD.

Transfection of primary brain capillary endothelial cells for protein synthesis and secretion of recombinant erythropoietin: a strategy to enable protein delivery to the brain

Treatment of chronic disorders affecting the central nervous system (CNS) is complicated by the inability of drugs to cross the blood-brain barrier (BBB). Non-viral gene therapy applied to brain capillary endothelial cells (BCECs) denotes a novel approach to overcome the restraints in this passage, as turning BCECs into recombinant protein factories by transfection could result in protein secretion further into the brain. The present study aims to investigate the possibility of transfecting primary rat brain endothelial cells (RBECs) for recombinant protein synthesis and secretion of the neuroprotective protein erythropoietin (EPO). We previously showed that 4% of RBECs with BBB properties can be transfected without disrupting the BBB integrity in vitro, but it can be questioned whether this is sufficient to enable protein secretion at therapeutic levels. The present study examined various transfection vectors, with regard to increasing the transfection efficiency without disrupting the BBB integrity. Lipofectamine 3000™ was the most potent vector compared to polyethylenimine (PEI) and Turbofect. When co-cultured with astrocytes, the genetically modified RBECs secreted recombinant EPO into the cell culture medium both luminally and abluminally, and despite lower levels of EPO reaching the abluminal chamber, the amount of recombinant EPO was sufficient to evolve a biological effect on astrocytes cultured at the abluminal side in terms of upregulated gene expression of brain-derived neurotropic factor (BDNF). In conclusion, non-viral gene therapy to RBECs leads to protein secretion and signifies a method for therapeutic proteins to target cells inside the CNS otherwise omitted due to the BBB.

Gene therapy and editing: Novel potential treatments for neuronal channelopathies

Pharmaceutical treatment can be inadequate, non-effective, or intolerable for many people suffering from a neuronal channelopathy. Development of novel treatment options, particularly those with the potential to be curative is warranted. Gene therapy approaches can permit cell-specific modification of neuronal and circuit excitability and have been investigated experimentally as a therapy for numerous neurological disorders, with clinical trials for several neurodegenerative diseases ongoing. Channelopathies can arise from a wide array of gene mutations; however they usually result in periods of aberrant network excitability. Therefore gene therapy strategies based on up or downregulation of genes that modulate neuronal excitability may be effective therapy for a wide range of neuronal channelopathies. As many channelopathies are paroxysmal in nature, optogenetic or chemogenetic approaches may be well suited to treat the symptoms of these diseases. Recent advances in gene-editing technologies such as the CRISPR-Cas9 system could in the future result in entirely novel treatment for a channelopathy by repairing disease-causing channel mutations at the germline level. As the brain may develop and wire abnormally as a consequence of an inherited or de novo channelopathy, the choice of optimal gene therapy or gene editing strategy will depend on the time of intervention (germline, neonatal or adult). This article is part of the Special Issue entitled 'Channelopathies.'

RNAi of Grp78 may disturb the fusion of ICR mouse palate cultured in vitro

RNA interference (RNAi) is a powerful tool to silence or minimize gene expression, and palate culture in vitro is an important technique for study of the palate development. Our previous study demonstrated that the gene expression of glucose-regulated protein-78 (Grp78) was downregulation in the all-trans retinoic acid-induced mouse models of cleft palate (CP) during embryogenesis. To find the role of Grp78, the small interfering RNA (siRNA) of this gene carried by fluorescent vector was injected with a microinjector, through which about 30 pmol siRNA was injected into the Institute of Cancer Research (ICR) mouse palate explants. After 6, 12, 24, 48, and 72 h, these palate explants were removed from culture to observe their fluorescent and Alcian blue-staining phenotypes, and the expression of the unfolded protein response (UPR) key members (Grp78, Inositol-responsive enzyme 1, protein kinase RNA-like endoplasmic reticulum kinase, activating transcription factor-6 and X-box binding protein-1) was measured. After cultured for 72 h, the partially or completely fused bilateral palates were observed in the control siRNA group, while CPs were found in the Grp78 siRNA group. In the Grp78 siRNA group, the relatively mRNA abundance of the key genes belonged to UPR at each time point was lower than that of the control siRNA group, and their protein expression also displayed the same change. By the system of RNAi strategies with mouse palate culture, we found the siRNA of Grp78 disturbed the fusion of mouse palate cultured in vitro.

Gene therapy targeting mitochondrial pathway in Parkinson's disease

Parkinson's disease (PD) presents a relative selective localization of pathology to substantia nigra and well-defined motor symptoms caused by dopaminergic degeneration that makes it an ideal target for gene therapy. Parallel progress in viral vector systems enables the delivery of therapeutic genes directly into brain with reasonable safety along with sustained transgene expression. To date, gene therapy for PD that has reached clinical trial evaluation is mainly based on symptomatic approach that involves enzyme replacement strategy and restorative approach that depends on the addition of neurotrophic factors. Mitochondrial dysregulation, such as reduced complex I activity, increased mitochondria-derived reactive oxygen species (ROS) production, ROS-mediated mitochondrial DNA damage, bioenergetic failure, and perturbation of mitochondrial dynamics and mitophagy, has long been implicated in the pathogenesis of PD. Many of mutated genes linked to familial forms of PD affect these mitochondrial features. In this review, we discuss the recent progress that has been made in preclinical development of gene therapy targeting the mitochondrial pathway as disease modifying approach for PD. This review focuses on the potential therapeutic efficacy of candidate genes, including Parkin, PINK1, alpha synuclein, PGC-1 alpha, and anti-apoptotic molecules.