Intranasal delivery: An attractive route for the administration of nucleic acid based therapeutics for CNS disorders

Intranasal administration of antiseizure drugs using new formulation trends: one step closer to reach clinical trials

INTRODUCTION

Although there are numerous options for epilepsy treatment, its effective control continues unsatisfactory. Thus, search for alternative therapeutic options to improve the efficacy/safety binomial of drugs becomes very attractive to investigate. In this context, intranasal administration of antiseizure drugs formulated on state-of-the-art nanosystems can be a promising strategy.

AREAS COVERED

This work gives a comprehensive overview of different intranasal nanosystems for antiseizure drug administration developed and evaluated on preclinical studies over the last 10 years and published in 'PubMed' and 'Web of Science' databases. Additionally, it highlights their pharmaceutical critical quality attributes and in vivo pharmacological outputs that might infer possible results when transposing to clinical trials.

EXPERT OPINION

Research into optimized nanosystems encapsulating antiseizure drugs to enhance direct nose-to-brain delivery has increased over the last years. Particularly, the interest in formulating first- and second-generation antiseizure drugs in nanoparticles is here highlighted, having demonstrated its in vivo safety and improvement on pharmacokinetic and efficacy outputs. Still, none of them were brought to clinical trials. Thus, considering the existing barriers between preclinical and clinical trials, if supported by robust and targeted quality by design approaches, intranasal drug delivery can be presented as a valid and superior alternative for epilepsy treatment.

Role of Nanotechnology in Ischemic Stroke: Advancements in Targeted Therapies and Diagnostics for Enhanced Clinical Outcomes

Each year, the number of cases of strokes and deaths due to this is increasing around the world. This could be due to work stress, lifestyles, unhealthy food habits, and several other reasons. Currently, there are several traditional methods like thrombolysis and mechanical thrombectomy for managing strokes. The current approach has several limitations, like delayed diagnosis, limited therapeutic delivery, and risks of secondary injuries. So, there is a need for some effective and reliable methods for the management of strokes, which could help in early diagnosis followed by the treatment of strokes. Nanotechnology has played an immense role in managing strokes, and recently, it has emerged as a transformative solution offering innovative diagnostic tools and therapeutic strategies. Nanoparticles (NPs) belonging to several classes, including metallic (metallic and metal oxide), organic (lipids, liposome), and carbon, can cross the blood-brain barrier and may exhibit immense potential for managing various strokes. Moreover, these NPs have exhibited promise in improving imaging specificity and therapeutic delivery by precise drug delivery and real-time monitoring of treatment efficacy. Nanomaterials like cerium oxide (CeO2) and liposome-encapsulated agents have neuroprotective properties that reduce oxidative stress and promote neuroregeneration. In the present article, the authors have emphasized the significant advancements in the nanomedicine management of stroke, including NPs-based drug delivery systems, neuroprotective and neuroregenerative therapies, and multimodal imaging advancements.

Evaluation of an Antisense Oligonucleotide Targeting CAG Repeats: A Patient-Customized Therapy Study for Huntington's Disease

Huntington's disease is a genetic disorder characterized by progressive neuronal cell damage in some areas of the brain; symptoms are commonly associated with chorea, rigidity and dystonia. The symptoms in Huntington's Disease are caused by a pathological increase in the number of Cytokine-Adenine-Guanine (CAG) repeats on the first exon of the Huntingtin gene, which causes a protein to have an excessive number of glutamine residues; this alteration leads to a change in the protein's conformation and function. Therefore, the purpose of this work was to design, synthesize and evaluate an antisense oligonucleotide (ASO; 95 nucleotides) HTT 90-5 directed to the Huntingtin CAG repeats in primary leukocyte culture cells from a patient with Huntington's Disease; approximately 500,000 leukocytes per well extracted from venous blood were used, to which 100 pMol of ASO were administered, and the expression of Huntingtin was subsequently evaluated at 72 h by RT-PCR. Our results showed that the administration of the HTT 90-5 antisense decreased the expression of Huntingtin mRNA in the primary culture leukocyte cells from our patient. These results suggest that the use of long antisense targeting the CAG Huntingtin cluster may be an option to decrease the expression of Huntingtin and probably could be adjusted depending on the number of CAG repeats in the cluster.

Drop to Gate Nasal Drops Attenuates Sepsis-Induced Cognitive Dysfunction

Nasal administration can bypass the blood-brain barrier and directly deliver drugs to the brain, providing a non-invasive route for central nervous system (CNS) diseases. Inspired by the appearance that a gate can block the outside world and the characteristics of the sol-gel transition can form a "gate" in the nasal cavity, a Drop to Gate nasal drop (DGND) is designed to set a gate in nose, which achieves protecting role from the influence of nasal environment. The DGND demonstrates the efficiency and application prospect of delivering drugs to the brain through the N-to-B. The effective concentration of single administration is increased through the hydrophobic interaction between C8-GelMA and SRT1720 (SA), and then cross-linked under UV to form nanogel, which can respond to MMP in the inflammatory microenvironment of sepsis-induced cognitive dysfunction. Finally, the SA/nanogel is compounded into the thermogel, which can respond to the nasal cavity temperature to form DGND in situ, increasing the residence time and delivery efficiency of drugs in the nasal cavity. In vitro, the DGND alleviates lipopolysaccharides (LPS)-induced BV2 inflammation. In vivo, DGND effectively targets the nasal mucosa and deliver drugs to the brain, which activate Sirt1 to alleviate inflammation mediated by microglia and improve cognitive dysfunction in sepsis mice.

Targeting and engineering long non-coding RNAs for cancer therapy

RNA therapeutics (RNATx) aim to treat diseases, including cancer, by targeting or employing RNA molecules for therapeutic purposes. Amongst the most promising targets are long non-coding RNAs (lncRNAs), which regulate oncogenic molecular networks in a cell type-restricted manner. lncRNAs are distinct from protein-coding genes in important ways that increase their therapeutic potential yet also present hurdles to conventional clinical development. Advances in genome editing, oligonucleotide chemistry, multi-omics and RNA engineering are paving the way for efficient and cost-effective lncRNA-focused drug discovery pipelines. In this Review, we present the emerging field of lncRNA therapeutics for oncology, with emphasis on the unique strengths and challenges of lncRNAs within the broader RNATx framework. We outline the necessary steps for lncRNA therapeutics to deliver effective, durable, tolerable and personalized treatments for cancer.

Enolase inhibitors as therapeutic leads for Naegleria fowleri infection

Infections with the pathogenic free-living amoebae Naegleria fowleri can lead to life-threatening illnesses including catastrophic primary amoebic meningoencephalitis (PAM). Efficacious treatment options for these infections are lacking and the mortality rate remains >95% in the US. Glycolysis is very important for the infectious trophozoite lifecycle stage and inhibitors of glucose metabolism have been found to be toxic to the pathogen. Recently, human enolase 2 (ENO2) phosphonate inhibitors have been developed as lead agents to treat glioblastoma multiforme (GBM). These compounds, which cure GBM in a rodent model, are well-tolerated in mammals because enolase 1 (ENO1) is the predominant isoform used systemically. Here, we describe findings that demonstrate these agents are potent inhibitors of N. fowleri ENO (NfENO) and are lethal to amoebae. In particular, (1-hydroxy-2-oxopiperidin-3-yl) phosphonic acid (HEX) was a potent enzyme inhibitor (IC50 = 0.14 ± 0.04 μM) that was toxic to trophozoites (EC50 = 0.21 ± 0.02 μM) while the reported CC50 was >300 μM. Molecular docking simulation revealed that HEX binds strongly to the active site of NfENO with a binding affinity of -8.6 kcal/mol. Metabolomic studies of parasites treated with HEX revealed a 4.5 to 78-fold accumulation of glycolytic intermediates upstream of NfENO. Last, nasal instillation of HEX increased longevity of amoebae-infected rodents. Two days after infection, animals were treated for 10 days with 3 mg/kg HEX, followed by one week of observation. At the end of the one-week observation, eight of 12 HEX-treated animals remained alive (resulting in an indeterminable median survival time) while one of 12 vehicle-treated rodents remained, yielding a median survival time of 10.9 days. However, intranasal HEX delivery was not curative as brains of six of the eight survivors were positive for amoebae. These findings suggest that HEX requires further evaluation to develop as a lead for treatment of PAM.

Functionalized nanoparticles to deliver nucleic acids to the brain for the treatment of Alzheimer's disease

Brain-targeted gene delivery across the blood-brain barrier (BBB) is a significant challenge in the 21st century for the healthcare sector, particularly in developing an effective treatment strategy against Alzheimer's disease (AD). The Internal architecture of the brain capillary endothelium restricts bio-actives entry into the brain. Additionally, therapy with nucleic acids faces challenges like vulnerability to degradation by nucleases and potential immune responses. Functionalized nanocarrier-based gene delivery approaches have resulted in safe and effective platforms. These nanoparticles (NPs) have demonstrated efficacy in protecting nucleic acids from degradation, enhancing transport across the BBB, increasing bioavailability, prolonging circulation time, and regulating gene expression of key proteins involved in AD pathology. We provided a detailed review of several nanocarriers and targeting ligands such as cell-penetrating peptides (CPPs), endogenous proteins, and antibodies. The utilization of functionalized NPs extends beyond a singular system, serving as a versatile platform for customization in related neurodegenerative diseases. Only a few numbers of bioactive regimens can go through the BBB. Thus, exploring functionalized NPs for brain-targeted gene delivery is of utmost necessity. Currently, genes are considered high therapeutic potential molecules for altering any disease-causing gene. Through surface modification, nanoparticulate systems can be tailored to address various diseases by replacing the target-specific molecule on their surface. This review article presents several nanoparticulate delivery systems, such as lipid NPs, polymeric micelles, exosomes, and polymeric NPs, for nucleic acids delivery to the brain and the functionalization strategies explored in AD research.

Effects of Nozzle Retraction Elimination on Spray Distribution in Middle-Posterior Turbinate Regions: A Comparative Study

The standard multi-dose nasal spray pump features an integrated actuator and nozzle, which inevitably causes a retraction of the nozzle tip during application. The retraction stroke is around 5.5 mm and drastically reduces the nozzle's insertion depth, which further affects the initial nasal spray deposition and subsequent translocation, potentially increasing drug wastes and dosimetry variability. To address this issue, we designed a new spray pump that separated the nozzle from the actuator and connected them with a flexible tube, thereby eliminating nozzle retraction during application. The objective of this study is to test the new device's performance in comparison to the conventional nasal pump in terms of spray generation, plume development, and dosimetry distribution. For both devices, the spray droplet size distribution was measured using a laser diffraction particle analyzer. Plume development was recorded with a high-definition camera. Nasal dosimetry was characterized in two transparent nasal cavity casts (normal and decongested) under two breathing conditions (breath-holding and constant inhalation). The nasal formulation was a 0.25% w/v methyl cellulose aqueous solution with a fluorescent dye. For each test case, the temporospatial spray translocation in the nasal cavity was recorded, and the final delivered doses were quantified in five nasal regions. The results indicate minor differences in droplet size distribution between the two devices. The nasal plume from the new device presents a narrower plume angle. The head orientation, the depth at which the nozzle is inserted into the nostril, and the administration angle play crucial roles in determining the initial deposition of nasal sprays as well as the subsequent translocation of the liquid film/droplets. Quantitative measurements of deposition distributions in the nasal models were augmented with visualization recordings to evaluate the delivery enhancements introduced by the new device. With an extension tube, the modified device produced a lower spray output and delivered lower doses in the front, middle, and back turbinate than the conventional nasal pump. However, sprays from the new device were observed to penetrate deeper into the nasal passages, predominantly through the middle-upper meatus. This resulted in consistently enhanced dosing in the middle-upper turbinate regions while at the cost of higher drug loss to the pharynx.

Biodistribution of Radioactively Labeled Splice Modulating Antisense Oligonucleotides After Intracerebroventricular and Intrathecal Injection in Mice

Antisense oligonucleotides (AONs) are promising therapeutic candidates, especially for neurological diseases. Intracerebroventricular (ICV) injection is the predominant route of administration in mouse studies, while in clinical trials, intrathecal (IT) administration is mostly used. There is little knowledge on the differences in distribution of these injection methods within the same species over time. In this study, we compared the distribution of splice-switching AONs targeting exon 15 of amyloid precursor protein pre-mRNA injected via the ICV and IT route in mice. The AON was labeled with radioactive indium-111 and mice were imaged using single-photon emission computed tomography (SPECT) 0, 4, 24, 48, 72, and 96 h after injection. In vivo SPECT imaging showed 111In-AON activity diffused throughout the central nervous system (CNS) in the first hours after injection. The 111In-AON activity in the CNS persisted over the course of 4 days, while signal in the kidneys rapidly decreased. Postmortem counting in different organs and tissues showed very similar distribution of 111In-AON activity throughout the body, while the signal in the different brain regions was higher with ICV injection. Overall, IT and ICV injection have very similar distribution patterns in the mouse, but ICV injection is much more effective in reaching the brain.

RNA therapeutics: Molecular mechanisms, and potential clinical translations

RNA therapies involve the utilization of natural and artificial RNA molecules to control the expression and function of cellular genes and proteins. Initializing from 1990s, RNA therapies now show the rapid growth in the development and application of RNA therapeutics for treating various conditions, especially for undruggable diseases. The outstanding success of recent mRNA vaccines against COVID-19 infection again highlighted the important role of RNA therapies in future medicine. In this review, we will first briefly provide the crucial investigations on RNA therapy, from the first pieces of discovery on RNA molecules to clinical applications of RNA therapeutics. We will then classify the mechanisms of RNA therapeutics from various classes in the treatment of diseases. To emphasize the huge potential of RNA therapies, we also provide the key RNA products that have been on clinical trials or already FDA-approved. With comprehensive knowledge on RNA biology, and the advances in analysis, technology and computer-aid science, RNA therapies can bring a promise to be more expanding to the market in the future.

Enolase inhibitors as therapeutic leads for Naegleria fowleri infection

Infections with the pathogenic free-living amoebae Naegleria fowleri can lead to life-threatening illnesses including catastrophic primary amebic meningoencephalitis (PAM). Efficacious treatment options for these infections are lacking and the mortality rate remains >95% in the US. Glycolysis is very important for the infectious trophozoite lifecycle stage and inhibitors of glucose metabolism have been found to be toxic to the pathogen. Recently, human enolase 2 (ENO2) phosphonate inhibitors have been developed as lead agents to treat glioblastoma multiforme (GBM). These compounds, which cure GBM in a rodent model, are well-tolerated in mammals because enolase 1 (ENO1) is the predominant isoform used systemically. Here, we describe findings that demonstrate that these agents are potent inhibitors of N. fowleri ENO ( Nf ENO) and are lethal to amoebae. In particular, (1-hydroxy-2-oxopiperidin-3-yl) phosphonic acid (HEX) was a potent enzyme inhibitor (IC 50 value of 0.14 ± 0.04 µM) that was toxic to trophozoites (EC 50 value of 0.21 ± 0.02 µM) while the reported CC 50 was >300 µM. Molecular docking simulation revealed that HEX binds strongly to the active site of Nf ENO with a binding affinity of -8.6 kcal/mol. Metabolomic studies of parasites treated with HEX revealed a 4.5 to 78-fold accumulation of glycolytic intermediates upstream of Nf ENO. Last, nasal instillation of HEX increased longevity of amoebae-infected rodents. Two days after infection, animals were treated for 10 days with 3 mg/kg HEX, followed by one week of observation. At the conclusion of the experiment, eight of 12 HEX-treated animals remained alive (resulting in an indeterminable median survival time) while one of 12 vehicle-treated rodents remained, yielding a median survival time of 10.9 days. Brains of six of the eight survivors were positive for amoebae, suggesting the agent at the tested dose suppressed, but did not eliminate, infection. These findings suggest that HEX is a promising lead for the treatment of PAM.

Advances in RNA therapeutics for modulation of 'undruggable' targets

Over the past decades, drug discovery utilizing small pharmacological compounds, fragment-based therapeutics, and antibody therapy have significantly advanced treatment options for many human diseases. However, a major bottleneck has been that>70% of human proteins/genomic regions are 'undruggable' by the above-mentioned approaches. Many of these proteins constitute essential drug targets against complex multifactorial diseases like cancer, immunological disorders, and neurological diseases. Therefore, alternative approaches are required to target these proteins or genomic regions in human cells. RNA therapeutics is a promising approach for many of the traditionally 'undruggable' targets by utilizing methods such as antisense oligonucleotides, RNA interference, CRISPR/Cas-based genome editing, aptamers, and the development of mRNA therapeutics. In the following chapter, we will put emphasis on recent advancements utilizing these approaches against challenging drug targets, such as intranuclear proteins, intrinsically disordered proteins, untranslated genomic regions, and targets expressed in inaccessible tissues.

Breaking the mold with RNA-a "RNAissance" of life science

In the past decade, RNA therapeutics have gone from being a promising concept to one of the most exciting frontiers in healthcare and pharmaceuticals. The field is now entering what many call a renaissance or "RNAissance" which is being fueled by advances in genetic engineering and delivery systems to take on more ambitious development efforts. However, this renaissance is occurring at an unprecedented pace, which will require a different way of thinking if the field is to live up to its full potential. Recognizing this need, this article will provide a forward-looking perspective on the field of RNA medical products and the potential long-term innovations and policy shifts enabled by this revolutionary and game-changing technological platform.

Innovative Genoceuticals in Human Gene Therapy Solutions: Challenges and Safe Clinical Trials of Orphan Gene Therapy Products

The success of gene therapy attempts is controversial and inconclusive. Currently, it is popular among the public, the scientific community, and manufacturers of Gene Therapy Medical Products. In the absence of any remedy or treatment options available for untreatable inborn metabolic orphan or genetic diseases, cancer, or brain diseases, gene therapy treatment by genoceuticals and T-cells for gene editing and recovery remains the preferred choice as the last hope. A new concept of "Genoceutical Gene Therapy" by using orphan 'nucleic acid-based therapy' aims to introduce scientific principles of treating acquired tissue damage and rare diseases. These Orphan Genoceuticals provide new scope for the 'genodrug' development and evaluation of genoceuticals and gene products for ideal 'gene therapy' use in humans with marketing authorization application (MAA). This perspective study focuses on the quality control, safety, and efficacy requirements of using 'nucleic acid-based and human cell-based new gene therapy' genoceutical products to set scientific advice on genoceutical-based 'orphan genodrug' design for clinical trials as per Western and European guidelines. The ethical Western FDA and European EMA guidelines suggest stringent legal and technical requirements on genoceutical medical products or orphan genodrug use for other countries to frame their own guidelines. The introduction section proposes lessknown 'orphan drug-like' properties of modified RNA/DNA, human cell origin gene therapy medical products, and their transgene products. The clinical trial section explores the genoceutical sources, FDA/EMA approvals for genoceutical efficacy criteria with challenges, and ethical guidelines relating to gene therapy of specific rare metabolic, cancer and neurological diseases. The safety evaluation of approved genoceuticals or orphan drugs is highlighted with basic principles and 'genovigilance' requirements (to observe any adverse effects, side effects, developed signs/symptoms) to establish their therapeutic use. Current European Union and Food and Drug Administration guidelines continuously administer fast-track regulatory legal framework from time to time, and they monitor the success of gene therapy medical product efficacy and safety. Moreover, new ethical guidelines on 'orphan drug-like genoceuticals' are updated for biodistribution of the vector, genokinetics studies of the transgene product, requirements for efficacy studies in industries for market authorization, and clinical safety endpoints with their specific concerns in clinical trials or public use.

RNAi therapies: Expanding applications for extrahepatic diseases and overcoming delivery challenges

The era of RNA medicine has become a reality with the success of messenger RNA (mRNA) vaccines against COVID-19 and the approval of several RNA interference (RNAi) agents in recent years. Particularly, therapeutics based on RNAi offer the promise of targeting intractable and previously undruggable disease genes. Recent advances have focused in developing delivery systems to enhance the poor cellular uptake and insufficient pharmacokinetic properties of RNAi therapeutics and thereby improve its efficacy and safety. However, such approach has been mainly achieved via lipid nanoparticles (LNPs) or chemical conjugation with N-Acetylgalactosamine (GalNAc), thus current RNAi therapy has been limited to liver diseases, most likely to encounter liver-targeting limitations. Hence, there is a huge unmet medical need for intense evolution of RNAi therapeutics delivery systems to target extrahepatic tissues and ultimately extend their indications for treating various intractable diseases. In this review, challenges of delivering RNAi therapeutics to tumors and major organs are discussed, as well as their transition to clinical trials. This review also highlights innovative and promising preclinical RNAi-based delivery platforms for the treatment of extrahepatic diseases.

mRNA nanodelivery systems: targeting strategies and administration routes

With the great success of coronavirus disease (COVID-19) messenger ribonucleic acid (mRNA) vaccines, mRNA therapeutics have gained significant momentum for the prevention and treatment of various refractory diseases. To function efficiently in vivo and overcome clinical limitations, mRNA demands safe and stable vectors and a reasonable administration route, bypassing multiple biological barriers and achieving organ-specific targeted delivery of mRNA. Nanoparticle (NP)-based delivery systems representing leading vector approaches ensure the successful intracellular delivery of mRNA to the target organ. In this review, chemical modifications of mRNA and various types of advanced mRNA NPs, including lipid NPs and polymers are summarized. The importance of passive targeting, especially endogenous targeting, and active targeting in mRNA nano-delivery is emphasized, and different cellular endocytic mechanisms are discussed. Most importantly, based on the above content and the physiological structure characteristics of various organs in vivo, the design strategies of mRNA NPs targeting different organs and cells are classified and discussed. Furthermore, the influence of administration routes on targeting design is highlighted. Finally, an outlook on the remaining challenges and future development toward mRNA targeted therapies and precision medicine is provided.