Current Gene Therapy - Volume 20, Issue 3, 2020

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.

NeuroAIDS, a disease incorporating both infectious and neurodegenerative pathways, is still a formidable challenge for the researchers to deal with. The primary concern for the treatment of neuroAIDS still remains the inaccessibility of the viral reservoir, making it indispensable for novel techniques to be continuously innovated. Since the brain serves as a reservoir for viral replication, it is pragmatic and a prerequisite to overcome the related barriers in order to improve the drug delivery to the brain. The current treatment ideology is based on the combinatorial approach of a mocktail of antiretroviral drugs. However, complete eradication of the disease could not be achieved. Thereby the arena of gene-based cellular delivery is trending and has created a niche for itself in the present scenario. To establish the supremacy of gene delivery, it is advisable to have a better understanding of the molecular mechanism involved in the due process. The mechanism associated with the activity of the anti-HIV gene lies in their intrinsic property to impart resistance to the HIV infection by targeting the viral entry channels. This review principally emphasizes on different types of gene therapies explored so far for the management of AIDS and its associated neurological conditions. Therefore it could rightly be said that we are at the crossroad where the need of the hour is to develop novel strategies for curbing AIDS and its associated neurological conditions.

Neurological disorders are one of the major threat for health care system as they put enormous socioeconomic burden. All aged populations are susceptible to one or other neurological problems with symptoms of neuroinflammation, neurodegeneration and cognitive dysfunction. At present, available pharmacotherapeutics are insufficient to treat these diseased conditions and in most cases, they provide only palliative effect. It was also found that the molecular etiology of neurological disorders is directly linked with the alteration in genetic makeup, which can be inherited or triggered by the injury, environmental toxins and by some existing disease. Therefore, to take care of this situation, gene therapy has emerged as an advanced modality that claims to permanently cure the disease by deletion, silencing or edition of faulty genes and by insertion of healthier genes. In this modality, vectors (viral and non-viral) are used to deliver targeted gene into a specific region of the brain via various routes. At present, gene therapy has shown positive outcomes in complex neurological disorders, such as Parkinson's disease, Alzheimer's disease, Huntington disease, Multiple sclerosis, Amyotrophic lateral sclerosis and in lysosomal storage disease. However, there are some limitations such as immunogenic reactions non-specificity of viral vectors and a lack of effective biomarkers to understand the efficacy of therapy. Considerable progress has been made to improve vector design, gene selection and targeted delivery. This review article deals with the current status of gene therapy in neurological disorders along with its clinical relevance, challenges and future prospective.

In recent times, several approaches for targeted gene therapy (GT) had been studied. However, the emergence of extracellular vesicles (EVs) as a shuttle carrying genetic information between cells has gained a lot of interest in scientific communities. Owing to their higher capabilities in dealing with short sequences of nucleic acid (mRNA, miRNA), proteins, recombinant proteins, exosomes, the most popular form of EVs are viewed as reliable biological therapeutic conveyers. They have natural access through every biological membrane and can be employed for site-specific and efficient drug delivery without eliciting any immune responses hence, qualifying as an ideal delivery vehicle. Also, there are many research studies conducted in the last few decades on using exosome-mediated gene therapy into developing an effective therapy with the concept of a higher degree of precision in gene isolation, purification and delivery mechanism loading, delivery and targeting protocols. This review discusses several facets that contribute towards developing an efficient therapeutic regime for gene therapy, highlighting limitations and drawbacks associated with current GT and suggested therapeutic regimes.

The limitations of conventional treatment therapies in Parkinson’s disorder, a common neurodegenerative disorder, lead to the development of an alternative gene therapy approach. Multiple treatment options targeting dopaminergic neuronal regeneration, production of enzymes linked with dopamine synthesis, subthalamic nucleus neurons, regulation of astrocytes and microglial cells and potentiating neurotrophic factors, were established. Viral vector-based dopamine delivery, prodrug approaches, fetal ventral mesencephalon tissue transplantation and dopamine synthesizing enzyme encoding gene delivery are significant therapies evidently supported by numerous trials. The review primarily elaborates on the significant role of glial cell-line derived neurotrophic factor in alleviating motor symptoms and the loss of dopaminergic neurons in Parkinson’s disease. Neuroprotective and neuroregenerative effects of GDNF were established via preclinical and clinical study outcomes. The binding of GDNF family ligands with associated receptors leads to the formation of a receptor-ligand complex activating Ret receptor of tyrosine kinase family, which is only expressed in dopaminergic neurons, playing an important role in Parkinson’s disease, via its association with the essential protein encoded genes. Furthermore, the review establishes delivery aspects, like ventricular delivery of recombinant GDNF, intraparenchymal and intraputaminal delivery using infusion catheters. The review highlights problems and challenges of GDNF delivery, and essential measures to overcome them, like gene therapy combinations, optimization of delivery vectors, newer targeting devices, motor symptoms curbing focused ultrasound techniques, modifications in patient selection criteria and development of novel delivery strategies based on liposomes and encapsulated cells, to promote safe and effective delivery of neurotrophic factor and establishment of routine treatment therapy for patients.

Background: Postprandial hyperglycemia considered to be a major risk factor for cerebrovascular complications. Objective: The current study was designed to elucidate the beneficial role of voglibose via in-silico in vitro to in-vivo studies in improving the postprandial glycaemic state by protection against strokeprone type 2 diabetes. Materials and Methods: In-Silico molecular docking and virtual screening were carried out with the help of iGEMDOCK+ Pymol+docking software and Protein Drug Bank database (PDB). Based on the results of docking studies, in-vivo investigation was carried out for possible neuroprotective action. T2DM was induced by a single injection of streptozotocin (90mg/kg, i.v.) to neonates. Six weeks after induction, voglibose was administered at the dose of 10mg/kg p.o. for two weeks. After eight weeks, diabetic rats were subjected to middle cerebral artery occlusion, and after 72 hours of surgery, neurological deficits were determined. The blood was collected for the determination of serum glucose, CK-MB, LDH and lipid levels. Brains were excised for determination of brain infarct volume, brain hemisphere weight difference, Na+-K+ ATPase activity, ROS parameters, NO levels, and aldose reductase activity. Results: In-silico docking studies showed good docking binding score for stroke associated proteins, which possibly hypotheses neuroprotective action of voglibose in stroke. In the present in-vivo study, pre-treatment with voglibose showed a significant decrease (p<0.05) in serum glucose and lipid levels. Voglibose has shown significant (p<0.05) reduction in neurological score, brain infarct volume, the difference in brain hemisphere weight. On biochemical evaluation, treatment with voglibose produced significant (p<0.05) decrease in CK-MB, LDH, and NO levels in blood and reduction in Na+-K+ ATPase, oxidative stress, and aldose reductase activity in brain homogenate. Conclusion: In-silico molecular docking and virtual screening studies and in-vivo studies in MCAo induced stroke, animal model outcomes support the strong anti-stroke signature for possible neuroprotective therapeutics.