Targeted transport of nanocarriers into brain for theranosis with rabies virus glycoprotein-derived peptide

Brain peptides modified exosome-mediated drug delivery system for adriamycin-induced nephropathy treatment

Mitigation of adriamycin (ADR)-induced nephropathy remains a significant challenge in clinical management. Brain-targeted administration of losartan demonstrates comparable nephroprotective effects at a 1:500 concentration relative to gavage administration. This study established an exosome-based nano-delivery platform (ExoACP) to reduce drug dosage for alleviating ADR-induced nephropathy. The platform was rigorously tested for toxicity and blood-brain barrier penetration. Additionally, the role and possible mechanism of ExoACP-Los in alleviating ADR-induced nephropathy in mice were investigated. ExoACP showed enhanced penetration in brain microvascular endothelial cells, with a 7.20-fold increase in uptake. In the ADR model, ExoACP-Los exhibited anti-inflammatory and anti-fibrotic effects by downregulating the renin-angiotensin system, reducing extracellular matrix deposition by nearly half. These findings suggest ExoACP-Los can alleviate ADR-induced nephropathy by enhancing targeted drug delivery to the brain while reducing losartan. Overall, ExoACP holds significant potential for future clinical applications in chronic nephropathy.

Peptides on patrol: Carrier systems for targeted delivery

The peptide is a small unit of protein that exhibits a diverse range of therapeutic applications, including but not limited to respiratory, inflammatory, oncologic, metabolic and neurological disorders. Peptides also play a significant role in signal transduction in cells. This chapter focuses on the delivery of peptides through the utilization of various carrier molecules, including liposomes, micelles, polymeric nanoparticles, and inorganic materials. These carriers facilitate targeted delivery and site-specific delivery of peptides. Different nanocarriers and therapeutic drug molecules also help with the delivery of peptides. Application to various diseases and different routes of delivery are described in this manuscript, along with current limitations and future prospects.

Rabies virus-mimicking liposomes for targeted gene therapy in Alzheimer's disease

RNA interference (RNAi) harbors significant potential for treating neurological disorders; nevertheless, limited efficacy has been discerned. The presence of barriers within the central nervous system, coupled with the inherent instability of nucleic acids within biological conditions, poses formidable challenges in advancing effective gene delivery strategies. In this study, we designed and prepared a virus-mimic non-viral gene vector, rabies virus glycoprotein (RVG29)-decorated liposome (f(Lipo)-RVG29), to deliver small interfering RNAs to the brain. Alzheimer's disease (AD) was chosen as a model of neurodegenerative disease in this context, and b-site APP cleaving enzyme silencing siRNA (siBACE1) was used. The developed liposomal delivery system has a particle size of under 80 nm with a spherical shape, positive zeta potential, and the ability to protect siRNA against nucleases. In vitro studies demonstrate that functionalizing the cationic liposome by the RVG29 targeting ligand significantly enhances the effectiveness of gene delivery and silencing. Examination through ex vivo imaging illustrates an increased deposition of fluorescent-labeled f(Lipo)-RVG29 within brain tissue after 12 h post application. Additionally, the in vivo delivery of f(Lipo)-RVG29 carrying siRNA has substantially suppressed BACE1 expression at both mRNA and protein levels within the brain tissue. Our results suggest that the developed non-viral vector could be a promising gene carrier system combining the synergistic effect of virus-mimic RVG29 ligand with bioinspired liposome that imitates the natural lipid bilayers of cell membranes for brain-targeted RNAi therapeutics.

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.

Extracellular vesicles as nanotheranostic platforms for targeted neurological disorder interventions

Central Nervous System (CNS) disorders represent a profound public health challenge that affects millions of people around the world. Diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), and traumatic brain injury (TBI) exemplify the complexities and diversities that complicate their early detection and the development of effective treatments. Amid these challenges, the emergence of nanotechnology and extracellular vesicles (EVs) signals a new dawn for treating and diagnosing CNS ailments. EVs are cellularly derived lipid bilayer nanosized particles that are pivotal in intercellular communication within the CNS and have the potential to revolutionize targeted therapeutic delivery and the identification of novel biomarkers. Integrating EVs with nanotechnology amplifies their diagnostic and therapeutic capabilities, opening new avenues for managing CNS diseases. This review focuses on examining the fascinating interplay between EVs and nanotechnology in CNS theranostics. Through highlighting the remarkable advancements and unique methodologies, we aim to offer valuable perspectives on how these approaches can bring about a revolutionary change in disease management. The objective is to harness the distinctive attributes of EVs and nanotechnology to forge personalized, efficient interventions for CNS disorders, thereby providing a beacon of hope for affected individuals. In short, the confluence of EVs and nanotechnology heralds a promising frontier for targeted and impactful treatments against CNS diseases, which continue to pose significant public health challenges. By focusing on personalized and powerful diagnostic and therapeutic methods, we might improve the quality of patients.

Blood-Brain Barrier (BBB)-Crossing Strategies for Improved Treatment of CNS Disorders

Blood-brain barrier (BBB) is a special biological property of the brain neurovascular unit (including brain microvessels and capillaries), which facilitates the transport of nutrients into the central nervous system (CNS) and exchanges metabolites but restricts passage of blood-borne neurotoxic substances and drugs/xenobiotics into CNS. BBB plays a crucial role in maintaining the homeostasis and normal physiological functions of CNS but severely impedes the delivery of drugs and biotherapeutics into CNS for treatment of neurological disorders. A variety of technologies have been developed in the past decade for brain drug delivery. Most of these technologies are still in preclinical stage and some are undergoing clinical studies. Only a few have been approved by regulatory agencies for clinical applications. This chapter will overview the strategies and technologies/approaches for brain drug delivery and discuss some of the recent advances in the field.

Overcoming brain barriers through surface-functionalized liposomes for glioblastoma therapy; current status, challenges and future perspective

Glioblastoma (GB) originating from astrocytes is considered a grade IV astrocytoma tumor with severe consequences. The blood-brain barrier (BBB) offers a major obstacle in drug delivery to the brain to overcome GB. The current treatment options possess limited efficacy and maximal systemic toxic effects in GB therapy. Emerging techniques such as targeted drug delivery offer significant advantages, including enhanced drug delivery to the tumor site by overcoming the BBB. This review article focuses on the status of surface-modified lipid nanocarriers with functional ligands to efficiently traverse the BBB and improve brain targeting for successful GB treatment. The difficulties with surface-functionalized liposomes and potential future directions for opening up novel treatment options for GB are highlighted.

New insights of miRNA molecular mechanisms in breast cancer brain metastasis and therapeutic targets

Brain metastases in breast cancer (BC) patients are often associated with a poor prognosis. Recent studies have uncovered the critical roles of miRNAs in the initiation and progression of BC brain metastasis, highlighting the disease's underlying molecular pathways. miRNA-181c, miRNA-10b, and miRNA-21, for example, are all overexpressed in BC patients. It has been shown that these three miRNAs help tumors grow and metastasize by targeting genes that control how cells work. On the other hand, miRNA-26b5p, miRNA-7, and miRNA-1013p are all downregulated in BC brain metastasis patients. They act as tumor suppressors by controlling the expression of genes related to cell adhesion, angiogenesis, and invasion. Therapeutic miRNA targeting has considerable promise in treating BC brain metastases. Several strategies have been proposed to modulate miRNA expression, including miRNA-Mimics, antagomirs, and small molecule inhibitors of miRNA biogenesis. This review discusses the aberrant expression of miRNAs and metastatic pathways that lead to the spread of BC cells to the brain. It also explores miRNA therapeutic target molecular mechanisms and BC brain metastasis challenges with advanced strategies. The targeting of certain miRNAs opens a new door for the development of novel therapeutic approaches for this devastating disease.

Nature vs. Manmade: Comparing Exosomes and Liposomes for Traumatic Brain Injury

Traumatic brain injury (TBI) of all severities is a significant public health burden, causing a range of effects that can lead to death or a diminished quality of life. Liposomes and mesenchymal stem cell-derived exosomes are two drug delivery agents with potential to be leveraged in the treatment of TBI by increasing the efficacy of drug therapies as well as having additional therapeutic effects. They exhibit several physical similarities, but key differences affect their performances as nanocarriers. Liposomes can be produced commercially at scale, and liposomes achieve higher encapsulation efficiency. Meanwhile, the intrinsic cargo and targeting moieties of exosomes, which liposomes lack, give exosomes a greater ability to facilitate neural regeneration, and exosomes do not trigger the infusion reactions that liposomes can. However, there are concerns about both exosomes and liposomes regarding interactions with tumors. The same routes of administration can be used for both exosomes and liposomes, resulting in somewhat different distribution throughout the body. While the effect of the nanocarrier type on accumulation in the brain is not concrete, targeting leads to increased accumulation of both exosomes and liposomes in the brain, upon which on-demand release can be used for both drug deliverers. Although neither have been applied to TBI in humans, preclinical trials have shown their immense potential, as have clinical trials pertaining to other brain injuries and conditions. While questions remain, research thus far shows that the various differences make exosomes a better choice of nanocarrier for TBI.

Inhibition of Protein Aggregation and Endoplasmic Reticulum Stress as a Targeted Therapy for α-Synucleinopathy

α-synuclein (α-syn) is an intrinsically disordered protein abundant in the central nervous system. Physiologically, the protein regulates vesicle trafficking and neurotransmitter release in the presynaptic terminals. Pathologies related to misfolding and aggregation of α-syn are referred to as α-synucleinopathies, and they constitute a frequent cause of neurodegeneration. The most common α-synucleinopathy, Parkinson's disease (PD), is caused by abnormal accumulation of α-syn in the dopaminergic neurons of the midbrain. This results in protein overload, activation of endoplasmic reticulum (ER) stress, and, ultimately, neural cell apoptosis and neurodegeneration. To date, the available treatment options for PD are only symptomatic and rely on dopamine replacement therapy or palliative surgery. As the prevalence of PD has skyrocketed in recent years, there is a pending issue for development of new disease-modifying strategies. These include anti-aggregative agents that target α-syn directly (gene therapy, small molecules and immunization), indirectly (modulators of ER stress, oxidative stress and clearance pathways) or combine both actions (natural compounds). Herein, we provide an overview on the characteristic features of the structure and pathogenic mechanisms of α-syn that could be targeted with novel molecular-based therapies.

Non-viral approaches for gene therapy and therapeutic genome editing across the blood-brain barrier

The success of brain-targeted gene therapy and therapeutic genome editing hinges on the efficient delivery of biologics bypassing the blood-brain barrier (BBB), which presents a significant challenge in the development of treatments for central nervous system disorders. This is particularly the case for nucleic acids and genome editors that are naturally excluded by the BBB and have poor chemical stability in the bloodstream and poor cellular uptake capability, thereby requiring judiciously designed nanovectors administered systemically for intracellular delivery to brain cells such as neurons. To overcome this obstacle, various strategies for bypassing the BBB have been developed in recent years to deliver biologics to the brain via intravenous administration using non-viral vectors. This review summarizes various brain targeting strategies and recent representative reports on brain-targeted non-viral delivery systems that allow gene therapy and therapeutic genome editing via intravenous administration, and highlights ongoing challenges and future perspectives for systemic delivery of biologics to the brain via non-viral vectors.

Poly (β-amino Ester) Nanoparticles Modified with a Rabies Virus-derived peptide for the Delivery of ASCL1 Across a 3D In Vitro Model of the Blood Brain Barrier

Gene editing has emerged as a therapeutic approach to manipulate the genome for killing cancer cells, protecting healthy tissues, and improving immune response to a tumor. The gene editing tool achaete-scute family bHLH transcription factor 1 CRISPR guide RNA (ASCL1-gRNA) is known to restore neuronal lineage potential, promote terminal differentiation, and attenuate tumorigenicity in glioblastoma tumors. Here, we fabricated a polymeric nonviral carrier to encapsulate ASCL1-gRNA by electrostatic interactions and deliver it into glioblastoma cells across a 3D in vitro model of the blood-brain barrier (BBB). To mimic rabies virus (RV) neurotropism, gene-loaded poly (β-amino ester) nanoparticles are surface functionalized with a peptide derivative of rabies virus glycoprotein (RVG29). The capability of the obtained NPs, hereinafter referred to as RV-like NPs, to travel across the BBB, internalize into glioblastoma cells and deliver ASCL1-gRNA are investigated in a 3D BBB in vitro model through flow cytometry and CLSM microscopy. The formation of nicotinic acetylcholine receptors in the 3D BBB in vitro model is confirmed by immunochemistry. These receptors are known to bind to RVG29. Unlike Lipofectamine that primarily internalizes and transfects endothelial cells, RV-like NPs are capable to travel across the BBB, preferentially internalize glioblastoma cells and deliver ASCL1-gRNA at an efficiency of 10 % causing non-cytotoxic effects.

RVG Peptide-Functionalized Favipiravir Nanoparticle Delivery System Facilitates Antiviral Therapy of Neurotropic Virus Infection in a Mouse Model

Neurotropic viruses severely damage the central nervous system (CNS) and human health. Common neurotropic viruses include rabies virus (RABV), Zika virus, and poliovirus. When treating neurotropic virus infection, obstruction of the blood-brain barrier (BBB) reduces the efficiency of drug delivery to the CNS. An efficient intracerebral delivery system can significantly increase intracerebral delivery efficiency and facilitate antiviral therapy. In this study, a rabies virus glycopeptide (RVG) functionalized mesoporous silica nanoparticle (MSN) packaging favipiravir (T-705) was developed to generate T-705@MSN-RVG. It was further evaluated for drug delivery and antiviral treatment in a VSV-infected mouse model. The RVG, a polypeptide consisting of 29 amino acids, was conjugated on the nanoparticle to enhance CNS delivery. The T-705@MSN-RVG caused a significant decrease in virus titers and virus proliferation without inducing substantial cell damage in vitro. By releasing T-705, the nanoparticle promoted viral inhibition in the brain during infection. At 21 days post-infection (dpi), a significantly enhanced survival ratio (77%) was observed in the group inoculated with nanoparticle compared with the non-treated group (23%). The viral RNA levels were also decreased in the therapy group at 4 and 6 dpi compared with that of the control group. The T-705@MSN-RVG could be considered a promising system for CNS delivery for treating neurotropic virus infection.

Cyclodextrin-Based Nanoparticles for Delivery of Antisense Oligonucleotides Targeting Huntingtin

Huntington's disease (HD) is a progressive inherited neurodegenerative disease caused by a CAG repeat expansion in the huntingtin gene, which is translated into the pathologic mutant huntingtin (mHTT) protein. Despite the great potential of HTT lowering strategies and the numerous antisense oligonucleotides (ASOs) in pre- and clinical trials, sustained silencing of mHTT has not been achieved. As a strategy to improve ASO delivery, cyclodextrin-based nanoparticles (CDs) offer a promising approach. Here, three CDs with distinct chemical structures were designed and their efficacies were compared as potential platforms for the delivery of ASO targeting HTT. Results using striatal neurons and HD patient-derived fibroblasts indicate that modified γ-CDs exhibited the best uptake efficiency and successfully downregulated mHTT at protein and allele levels. The incorporation of the brain-targeting peptide RVG into the modified γ-CDs showed greater downregulation of mHTT protein and HD-causing allele SNP1 than untargeted ones in an in vitro blood-brain barrier model. Although the ASO sequence was designed as a nonallele-specific therapeutic approach, our strategy gives an additional benefit of some mHTT selectivity. Overall, this study demonstrated the CD platform's feasibility for delivering ASO-based therapeutics for HD treatment.

Micro-Nanocarriers Based Drug Delivery Technology for Blood-Brain Barrier Crossing and Brain Tumor Targeting Therapy

The greatest obstacle to using drugs to treat brain tumors is the blood-brain barrier (BBB), making it difficult for conventional drug molecules to enter the brain. Therefore, how to safely and effectively penetrate the BBB to achieve targeted drug delivery to brain tumors has been a challenging research problem. With the intensive research in micro- and nanotechnology in recent years, nano drug-targeted delivery technologies have shown great potential to overcome this challenge, such as inorganic nanocarriers, organic polymer-carriers, liposomes, and biobased carriers, which can be designed in different sizes, shapes, and surface functional groups to enhance their ability to penetrate the BBB and targeted drug delivery for brain tumors. In this review, the composition and overcoming patterns of the BBB are detailed, and then the hot research topics of drug delivery carriers for brain tumors in recent years are summarized, and their mechanisms of action on the BBB and the factors affecting drug delivery are described in detail, and the effectiveness of targeted therapy for brain tumors is evaluated. Finally, the challenges and dilemmas in developing brain tumor drug delivery systems are discussed, which will be promising in the future for targeted drug delivery to brain tumors based on micro-nanocarriers technology.

Transport of nanomedicines across the blood-brain barrier: Challenges and opportunities for imaging and therapy

The blood-brain barrier (BBB) is a protective and semipermeable border of endothelial cells that prevents toxins and foreign bodies to enter and damage the brain. Unfortunately, the BBB also hampers the development of pharmaceuticals targeting receptors, enzymes, or other proteins that lie beyond this barrier. Especially large molecules, such as monoclonal antibodies (mAbs) or nanoparticles, are prevented to enter the brain. The limited passage of these molecules partly explains why nanomedicines - targeting brain diseases - have not made it into the clinic to a great extent. As nanomedicines can target a wide range of targets including protein isoforms and oligomers or potentially deliver cytotoxic drugs safely to their targets, a pathway to smuggle nanomedicines into the brain would allow to treat brain diseases that are currently considered 'undruggable'. In this review, strategies to transport nanomedicines over the BBB will be discussed. Their challenges and opportunities will be highlighted with respect to their use for molecular imaging or therapies. Several strategies have been explored for this thus far. For example, carrier-mediated and receptor-mediated transcytosis (RMT), techniques to disrupt the BBB, nasal drug delivery or administering nanomedicines directly into the brain have been explored. RMT has been the most widely and successfully explored strategy. Recent work on the use of focused ultrasound based BBB opening has shown great promise. For example, successful delivery of mAbs into the brain has been achieved, even in a clinical setting. As nanomedicines bear the potential to treat incurable brain diseases, drug delivery technologies that can deliver nanomedicines into the brain will play an essential role for future treatment options.

MicroRNA delivery systems in glioma therapy and perspectives: A systematic review

Gliomas are the deadliest of all primary brain tumors, and they constitute a serious global health problem. MicroRNAs (miRNAs) are gene expression regulators associated with glioma pathogenesis. Thus, miRNAs represent potential therapeutic agents for treating gliomas. However, miRNAs have not been established as part of the regular clinical armamentarium. This systemic review evaluates current molecular and pre-clinical studies with the aim of defining the most appealing supramolecular platform for administering therapeutic miRNA to patients with gliomas. An integrated analysis suggested that cationic lipid nanoparticles, functionalized with octa-arginine peptides, represent a potentially specific, practical, non-invasive intervention for treating gliomas. This supramolecular platform allows loading both hydrophilic (miRNA) and hydrophobic (anti-tumor drugs, like temozolomide) molecules. This systemic review is the first to describe miRNA delivery systems targeted to gliomas that integrate several types of molecules as active ingredients. Further experimental validation is warranted to confirm the practical value of miRNA delivery systems.

Nature-inspired dynamic gene-loaded nanoassemblies for the treatment of brain diseases

Gene therapy has great potential to treat brain diseases. However, genetic drugs need to overcome a cascade of barriers for their full potential. The conventional delivery systems often struggle to meet expectations. Natural biological particles that are highly optimized for specific functions in body, can inspire optimization of dynamic gene-loaded nanoassemblies (DGN). The DGN refer to gene loaded nanoassemblies whose functions and structures are changeable in response to the biological microenvironments or can dynamically interact with tissues or cells. The nature-inspired DGN can meet the needs in brain diseases treatment, including i) Non-elimination in blood (N), ii) Across the blood-brain barrier (A), iii) Targeting cells (T), iv) Efficient uptake (U), v) Controllable release (R), vi) Eyeable (E)-abbreviated as the "NATURE". In this Review, from nature to "NATURE", we mainly summarize the specific application of nature-inspired DGN in the "NATURE" cascade process. Furthermore, the Review provides an outlook for this field.

Modified cyclodextrin-based nanoparticles mediated delivery of siRNA for huntingtin gene silencing across an in vitro BBB model

Huntington's disease (HD) is a neurodegenerative disorder caused by a mutation in the huntingtin (HTT) gene, leading to a toxic version of the HTT protein. There are currently no disease-modifying therapies available. In this scenario, gene-based treatments for HD aimed at lowering HTT levels have become one of the most promising emerging therapeutic options. To date, however, promising results have only been achieved following direct intrathecal or intracranial injections designed to circumvent the blood-brain barrier (BBB). Consequently, efforts to develop less invasive delivery platforms are highly desirable. Here, we described a novel delivery system based on modified cyclodextrin nanoparticles (CDs) loaded with small interfering RNAs (siRNAs) targeting HTT andcomplexed with the rabies virus glycoprotein(RVG), a BBB-shuttle peptide. Results using an in vitro BBB model, indicate the formulation successfully crosses the brain endothelial cells, releases the encapsulated siRNAs into the cytoplasm of neuronal cells, and mediates downregulation of HTT. In conclusion, the CD platform is a promising option for delivery of siRNA-based therapeutics for HD with wider potential to treat other diseases with a genetically validated target in the central nervous system.

The Effect of Oxidative Stress and Memantine-Incorporated Reactive Oxygen Species-Sensitive Nanoparticles on the Expression of N-Methyl-d-aspartate Receptor Subunit 1 in Brain Cancer Cells for Alzheimer's Disease Application

The aim of this study is to fabricate reactive oxygen species (ROS)-sensitive nanoparticles composed of succinyl β-cyclodextrin (bCDsu), memantine and thioketal linkages for application in Alzheimer's disease, and to investigate the suppression of N-methyl-d-aspartate (NMDA) receptor 1 (NMDAR1) in cells. Thioketal diamine was attached to the carboxyl group of bCDsu to produce thioketal-decorated bCDsu conjugates (bCDsu-thioketal conjugates) and memantine was conjugated with thioketal dicarboxylic acid (memantine-thioketal carboxylic acid conjugates). Memantine-thioketal carboxylic acid conjugates were attached to bCDsu-thioketal conjugates to produce bCDsu-thioketal-memantine (bCDsuMema) conjugates. SH-SY5Y neuroblastoma cells and U87MG cells were used for NMDAR1 protein expression and cellular oxidative stress. Nanoparticles of bCDsuMema conjugates were prepared by means of a dialysis procedure. Nanoparticles of bCDsuMema conjugates had small particle sizes less than 100 nm and their morphology was found to be spherical in transmission electron microscopy observations (TEM). Nanoparticles of bCDsuMema conjugates responded to H₂O₂ and disintegrated or swelled in aqueous solution. Then, the nanoparticles rapidly released memantine according to the concentration of H₂O₂. In an in vivo animal imaging study, thioketal-decorated nanoparticles labelled with fluorescent dye such as chlorin e6 (Ce6) showed that the fluorescence intensity was stronger in the brain than in other organs, indicating that bCDsuMema nanoparticles can efficiently target the brain. When cells were exposed to H₂O₂, the viability of cells was time-dependently decreased. Memantine or bCDsuMema nanoparticles did not practically affect the viability of the cells. Furthermore, a western blot assay showed that the oxidative stress produced in cells using H₂O₂ increased the expression of NMDAR1 protein in both SH-SY5Y and U87MG cells. Memantine or bCDsuMema nanoparticles efficiently suppressed the NMDAR1 protein, which is deeply associated with Alzheimer's disease. Fluorescence microscopy also showed that H₂O₂ treatment induced green fluorescence intensity, which represents intracellular ROS levels. Furthermore, H₂O₂ treatment increased the red fluorescence intensity, which represents the NMDAR1 protein, i.e., oxidative stress increases the expression of NMDAR1 protein level in both SH-SY5Y and U87MG cells. When memantine or bCDsuMema nanoparticles were treated in cells, the oxidative stress-mediated expression of NMDAR1 protein in cells was significantly decreased, indicating that bCDsuMema nanoparticles have the capacity to suppress NMDAR1 expression in brain cells, which has relevance in terms of applications in Alzheimer's disease.

An update on actively targeted liposomes in advanced drug delivery to glioma

High-grade glioma is one of the most aggressive types of cancer with a low survival rate ranging from 12 to 15 months after the first diagnosis. Though being the most common strategy for glioma therapy, conventional chemotherapy suffers providing the therapeutic dosage of common therapeutics mostly because of limited permeability of blood-brain barrier (BBB), and blood-brain tumor barrier (BBTB) to anticancer agents. Among various nanoformulations, liposomes are considered as the most popular carriers aimed for glioma therapy. However, non-targeted liposomes which passively accumulate in most of the cancer tissues mainly through the enhanced permeation and retention effect (EPR), may not be applicable for glioma therapy due to BBB tight junctions. In the recent decade, the surface modification of liposomes with different active targeting ligands has shown promising results by getting different chemotherapeutics across the BBB and BBTB and leading them into the glioma cells. The present review discusses the major barriers for drug delivery systems to glioma, elaborates the existing mechanisms for liposomes to traverse across the BBB, and explores the main strategies for incorporation of targeting ligands onto the liposomes. It subsequently investigates the most recent and relevant studies of actively targeted liposomes modified with antibodies, aptamers, monosaccharides, polysaccharides, proteins, and peptides applied for effective glioma therapy, and highlights the common challenges facing this area. Finally, the actively targeted liposomes undergoing preclinical and clinical studies for delivery of different anticancer agents to glioma cells will be reviewed.

Peptidic Connexin43 Therapeutics in Cardiac Reparative Medicine

Connexin (Cx43)-formed channels have been linked to cardiac arrhythmias and diseases of the heart associated with myocardial tissue loss and fibrosis. These pathologies include ischemic heart disease, ischemia-reperfusion injury, heart failure, hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, and Duchenne muscular dystrophy. A number of Cx43 mimetic peptides have been reported as therapeutic candidates for targeting disease processes linked to Cx43, including some that have advanced to clinical testing in humans. These peptides include Cx43 sequences based on the extracellular loop domains (e.g., Gap26, Gap 27, and Peptide5), cytoplasmic-loop domain (Gap19 and L2), and cytoplasmic carboxyl-terminal domain (e.g., JM2, Cx43tat, CycliCX, and the alphaCT family of peptides) of this transmembrane protein. Additionally, RYYN peptides binding to the Cx43 carboxyl-terminus have been described. In this review, we survey preclinical and clinical data available on short mimetic peptides based on, or directly targeting, Cx43, with focus on their potential for treating heart disease. We also discuss problems that have caused reluctance within the pharmaceutical industry to translate peptidic therapeutics to the clinic, even when supporting preclinical data is strong. These issues include those associated with the administration, stability in vivo, and tissue penetration of peptide-based therapeutics. Finally, we discuss novel drug delivery technologies including nanoparticles, exosomes, and other nanovesicular carriers that could transform the clinical and commercial viability of Cx43-targeting peptides in treatment of heart disease, stroke, cancer, and other indications requiring oral or parenteral administration. Some of these newly emerging approaches to drug delivery may provide a path to overcoming pitfalls associated with the drugging of peptide therapeutics.

Application progress of RVG peptides to facilitate the delivery of therapeutic agents into the central nervous system

The incidence of central nervous system (CNS) diseases is increasing with the aging population. However, it remains challenging to deliver drugs into the CNS because of the existence of a blood-brain barrier (BBB). Notably, rabies virus glycoprotein (RVG) peptides have been developed as delivery ligands for CNS diseases. So far, massive RVG peptide modified carriers have been reported, such as liposomes, micelles, polymers, exosomes, dendrimers, and proteins. Moreover, these drug delivery systems can encapsulate almost all small molecules and macromolecule drugs, including siRNA, microRNAs, DNA, proteins, and other nanoparticles, to treat various CNS diseases with efficient and safe drugs. In this review, targeted delivery systems with RVG peptide modified carriers possessing favorable biocompatibility and delivery efficiency are summarized.

Evolving new-age strategies to transport therapeutics across the blood-brain-barrier

A basic understanding of the blood-brain barrier (BBB) is essential for the novel advancements in targeting drugs specific to the brain. Neoplasm compromising the internal structure of BBB that results in impaired vasculature is called as blood tumor barrier (BTB). Besides, the BBB serves as a chief hindrance to the passage of a drug into the brain parenchyma. The small and hydrophilic drugs majorly display an absence of desired molecular characteristics required to cross the BBB. Furthermore, all classes of biologics have failed in the clinical trials of brain diseases over the past years since these biologics are large molecules that do not cross the BBB. Also, new strategies have been discovered that use the Trojan horse technology with the re-engineered biologics for BBB transport. Thus, this review delivers information about the different grades of tumors (I-IV) i.e. examples of BBB/BTB heterogenicity along with the different mechanisms for transporting the therapeutics into the brain tumors by crossing BBB. This review also provides insights into the emerging approaches of peptide delivery and the non-invasive and brain-specific molecular Trojan horse targeting technologies. Also, the several challenges in the clinical development of BBB penetrating IgG fusion protein have been discussed.

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.

Systemic exosomal miR-193b-3p delivery attenuates neuroinflammation in early brain injury after subarachnoid hemorrhage in mice

Background

Inflammation is a potential crucial factor in the pathogenesis of subarachnoid hemorrhage (SAH). Circulating microRNAs (miRNAs) are involved in the regulation of diverse aspects of neuronal dysfunction. The therapeutic potential of miRNAs has been demonstrated in several CNS disorders and is thought to involve modulation of neuroinflammation. Here, we found that peripherally injected modified exosomes (Exos) delivered miRNAs to the brains of mice with SAH and that the potential mechanism was regulated by regulation of neuroinflammation.

Methods

Next-generation sequencing (NGS) and qRT-PCR were used to define the global miRNA profile of plasma exosomes in aSAH patients and healthy controls. We peripherally injected RVG/Exos/miR-193b-3p to achieve delivery of miR-193b-3p to the brain of mice with SAH. The effects of miR-193b-3p on SAH were assayed using a neurological score, brain water content, blood-brain barrier (BBB) injury, and Fluoro-Jade C (FJC) staining. Western blotting analysis, enzyme-linked immunosorbent assay (ELISA), and qRT-PCR were used to measure various proteins and mRNA levels.

Results

NGS and qRT-PCR revealed that four circulating exosomal miRNAs were differentially expressed. RVG/Exos exhibited improved targeting to the brains of SAH mice. MiR-193b-3p suppressed the expression and activity of HDAC3, upregulating the acetylation of NF-κB p65. Finally, miR-193b-3p treatment mitigated the neurological behavioral impairment, brain edema, BBB injury, and neurodegeneration induced by SAH, and reduced inflammatory cytokine expression in the brains of mice after SAH.

Conclusions

Exos/miR-193b-3p treatment attenuated the inflammatory response by acetylation of the NF-κB p65 via suppressed expression and activity of HDAC3. These effects alleviated neurobehavioral impairments and neuroinflammation following SAH.

Targeted Theranostic of Cryptococcal Encephalitis by a Novel Polypyridyl Ruthenium Complex

Cryptococcus neoformans (C. neoformans) is one of the most well-known zoonotic fungal pathogens. Cryptococcal encephalitis remains a major cause of morbidity and mortality in immunocompromised hosts. Effective and targeting killing of C. neoformans in the brain is an essential approach to prevent and treat cryptococcal encephalitis. In this study, a fluorescent polypyridyl ruthenium complex RC-7, {[phen₂Ru(bpy-dinonyl)](PF₆)₂ (phen = 1,10-phenanthroline, bpy-dinonyl = 4,4'-dinonyl-2,2'-bipyridine)}, was screened out, which showed a highly fungicidal effect on C. neoformans. The values of minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) in antifungal activities were significantly lower than fluconazole as the control. Moreover, RC-7 was prepared as a brain-targeting nanoliposome (RDP-liposome; RDP is a peptide derived from rabies virus glycoprotein) for in vivo application. The results revealed that the liposomes could accumulate in the encephalitis brain and play an antifungal role. Compared with the cryptococcal encephalitis model mice, the RDP-liposomes remarkably prolonged the survival days of the encephalitis-bearing mice from 10 days to 24 days. Here, we introduce a polypyridyl ruthenium complex that could be used as a novel antifungal agent, and this study may have a broad impact on the development of targeted delivery based on ruthenium complex-loaded liposomes for theranostics of cryptococcal encephalitis.

Biomimetic drug-delivery systems for the management of brain diseases

Acting as a double-edged sword, the blood-brain barrier (BBB) is essential for maintaining brain homeostasis by restricting the entry of small molecules and most macromolecules from blood. However, it also largely limits the brain delivery of most drugs. Even if a drug can penetrate the BBB, its accumulation in the intracerebral pathological regions is relatively low. Thus, an optimal drug-delivery system (DDS) for the management of brain diseases needs to display BBB permeability, lesion-targeting capability, and acceptable safety. Biomimetic DDSs, developed by directly utilizing or mimicking the biological structures and processes, provide promising approaches for overcoming the barriers to brain drug delivery. The present review summarizes the biological properties and biomedical applications of the biomimetic DDSs including the cell membrane-based DDS, lipoprotein-based DDS, exosome-based DDS, virus-based DDS, protein template-based DDS and peptide template-based DDS for the management of brain diseases.

Neuroblastoma-targeting triangular gadolinium oxide nanoplates for precise excision of cancer

Neuroblastoma accounts for 8-10% of malignancies in infants and children. It is urgent to develop an appropriate theranostic agent for effective diagnosis and therapy of neuroblastoma. Herein, we constructed RVG peptide and IRDye800-conjugated bovine serum albumin-coated triangular gadolinium oxide nanoplates (RVG&IRDye800-Gd₂O₃ TNs) as a targeting MRI agent for the diagnosis of neuroblastoma preoperation and a fluorescence imaging agent for the guidance of the precise excision of the neuroblastoma in surgery. RVG&IRDye800-Gd₂O₃ TNs have uniform edge length. The RVG&IRDye800-Gd₂O₃ TNs show remarkably enhanced affinity to both mouse- and human-derived neuroblastoma cells compared with IRDye800-Gd₂O₃ TNs (3.07-fold and 3.02-fold, respectively). Because of the increased accumulation in tumor cells, RVG&IRDye800-Gd₂O₃ TNs exhibit signals threefold to fivefold higher than the surrounding normal tissues, which is propitious to the diagnosis of neuroblastoma preoperation and provides real-time visual guidance of the precise excision of the neuroblastoma. Most importantly, with the guidance of the fluorescence imaging agent, the survival rate increased from 0% to 80% 42 days after surgery compared with that in conventional surgery. These findings indicated that the RVG peptide combined with IRDye800-Gd₂O₃ TNs has the potential to improve the diagnosis and treatment of patients with neuroblastoma. STATEMENT OF SIGNIFICANCE: In this study, we prepared RVG peptide and IRDye800-conjugated bovine serum albumin-coated triangular gadolinium oxide nanoplates (RVG&IRDye800-Gd₂O₃ TNs) as a targeting MRI agent for the diagnosis of neuroblastoma preoperation and a fluorescence imaging agent for the guidance of the precise excision of the neuroblastoma during surgery. Neuroblastoma was accurately located by MRI imaging, and the tumor margin could be real-time monitored through near-infrared fluorescence imaging. The RVG&IRDye800-Gd₂O₃ TNs exhibit signals threefold to fivefold higher than those in the surrounding normal tissues, which is propitious to the diagnosis of the neuroblastoma preoperation and provides real-time visual guidance of the precise excision of the neuroblastoma. With the guidance of the fluorescence imaging agent in surgery, the survival rate increased from 0% to 80% 42 days after surgery compared with that in conventional surgery.

Short Peptide-Mediated Brain-Targeted Drug Delivery with Enhanced Immunocompatibility

Peptide ligands have been exploited as versatile tools to facilitate targeted delivery of nanocarriers. However, the effects of peptide ligands on immunocompatibility and therapeutic efficacy of liposomes remain intricate. Here, a short and stable brain targeted peptide ligand D8 was modified on the surface of doxorubicin-loaded liposomes (D8-sLip/DOX), demonstrating prolonged blood circulation and lower liver distribution in comparison to the long and stable D-peptide ligand ^DCDX-modified doxorubicin-loaded liposomes (^DCDX-sLip/DOX) by mitigating natural IgM absorption. Despite the improved pharmacokinetic profiles, D8-sLip/DOX exhibited comparable brain targeting capacity in ICR mice and antiglioblastoma efficacy to ^DCDX-sLip/DOX in nude mice bearing intracranial glioblastoma. However, dramatic accumulation of ^DCDX-sLip/DOX in liver (especially during the first 8 h after intravenous injection) resulted in pathological symptoms, including nuclei swelling, necrosis of liver cells, and inflammation. These results suggest that short peptide ligand-mediated brain-targeted drug delivery systems possessing enhanced immunocompatibility are promising to facilitate efficient brain transport with improved biosafety.