Translational challenges in advancing regenerative therapy for treating neurological disorders using nanotechnology

Lhx2 promotes axon regeneration of adult retinal ganglion cells and rescues neurodegeneration in mouse models of glaucoma

The axons of retinal ganglion cells (RGCs) form the optic nerve, transmitting visual information from the eye to the brain. Damage or loss of RGCs and their axons is the leading cause of visual functional defects in traumatic injury and degenerative diseases such as glaucoma. However, there are no effective clinical treatments for nerve damage in these neurodegenerative diseases. Here, we report that LIM homeodomain transcription factor Lhx2 promotes RGC survival and axon regeneration in multiple animal models mimicking glaucoma disease. Furthermore, following N-methyl-D-aspartate (NMDA)-induced excitotoxicity damage of RGCs, Lhx2 mitigates the loss of visual signal transduction. Mechanistic analysis revealed that overexpression of Lhx2 supports axon regeneration by systematically regulating the transcription of regeneration-related genes and inhibiting transcription of Semaphorin 3C (Sema3C). Collectively, our studies identify a critical role of Lhx2 in promoting RGC survival and axon regeneration, providing a promising neural repair strategy for glaucomatous neurodegeneration.

Revolutionizing Neurological Disorder Treatment: Integrating Innovations in Pharmaceutical Interventions and Advanced Therapeutic Technologies

Neurological disorders impose a significant burden on individuals, leading to disabilities and a reduced quality of life. However, recent years have witnessed remarkable advancements in pharmaceutical interventions aimed at treating these disorders. This review article aims to provide an overview of the latest innovations and breakthroughs in neurological disorder treatment, with a specific focus on key therapeutic areas such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, epilepsy, and stroke. This review explores emerging trends in drug development, including the identification of novel therapeutic targets, the development of innovative drug delivery systems, and the application of personalized medicine approaches. Furthermore, it highlights the integration of advanced therapeutic technologies such as gene therapy, optogenetics, and neurostimulation techniques. These technologies hold promise for precise modulation of neural circuits, restoration of neuronal function, and even disease modification. While these advancements offer hopeful prospects for more effective and tailored treatments, challenges such as the need for improved diagnostic tools, identification of new targets for intervention, and optimization of drug delivery methods will remain. By addressing these challenges and continuing to invest in research and collaboration, we can revolutionize the treatment of neurological disorders and significantly enhance the lives of those affected by these conditions.

Microfluidic Synthesis of Ultrasmall Chitosan/Graphene Quantum Dots Particles for Intranasal Delivery in Alzheimer's Disease Treatment

Nanoparticles (NPs) based therapies for Alzheimer's disease (AD) attract interest due to their ability to pass across or bypass the blood-brain barrier. Chitosan (CS) NPs or graphene quantum dots (GQDs) are promising drug carriers with excellent physicochemical and electrical properties. The current study proposes the combination of CS and GQDs in ultrasmall NP form not as drug carriers but as theranostic agents for AD. The microfluidic-based synthesis of the CS/GQD NPs with optimized characteristics makes them ideal for transcellular transfer and brain targeting after intranasal (IN) delivery. The NPs have the ability to enter the cytoplasm of C6 glioma cells in vitro and show dose and time-dependent effects on the viability of the cells. IN administration of the NPs to streptozotocin (STZ) induced AD-like models lead to a significant number of entrances of the treated rats to the target arm in the radial arm water maze (RAWM) test. It shows the positive effect of the NPs on the memory recovery of the treated rats. The NPs are detectable in the brain via in vivo bioimaging due to GQDs as diagnostic markers. The noncytotoxic NPs localize in the myelinated axons of hippocampal neurons. They do not affect the clearance of amyloid β (Aβ) plaques at intercellular space. Moreover, they showed no positive impact on the enhancement of MAP2 and NeuN expression as markers of neural regeneration. The memory improvement in treated AD rats may be due to neuroprotection via the anti-inflammation effect and regulation of the brain tissue microenvironment that needs to be studied.

Electric Field Effect on Inhibiting the Co-fibrillation of Amyloid Peptides by Modulating the Aggregation Pathway

With the revelation of the close link between Alzheimer's disease (AD) and type II diabetes (T2D) and the possible assembly of multiple amyloid peptides therein, it is critical to understand and regulate the co-fibrillation pathway between related amyloid peptides. Here, we show experimentally and theoretically that electric field (EF) inhibited hybrid amyloid fibrillation of β-amyloid peptide (Aβ) and human islet amyloid peptide (hIAPP) by modulating the hetero-aggregation pathway. Experimental results confirm that the β-sheet secondary structure of amyloid peptides would be disrupted under small static EF and accompanied by transforming fibril aggregates into amorphous particles in vitro. Molecular dynamics simulations further demonstrate that even with the transformation of the secondary structure from β-sheet to random coil, the strong interaction between Aβ and hIAPP peptides would remain largely unaffected under the small static EF, leading to the formation of amorphous nanoparticles observed in the experiments. This inhibitory effect of EF on the co-fibrillation of multiple amyloid peptides might contribute to reducing the mutual deterioration of different degenerative diseases and show great potential for the noninvasive treatment of amyloid-related diseases.

Coaxial Electrospun PLLA Fibers Modified with Water-Soluble Materials for Oligodendrocyte Myelination

Myelin sheaths are essential in maintaining the integrity of axons. Development of the platform for in vitro myelination would be especially useful for demyelinating disease modeling and drug screening. In this study, a fiber scaffold with a core-shell structure was prepared in one step by the coaxial electrospinning method. A high-molecular-weight polymer poly-L-lactic acid (PLLA) was used as the core, while the shell was a natural polymer material such as hyaluronic acid (HA), sodium alginate (SA), or chitosan (CS). The morphology, differential scanning calorimetry (DSC), Fourier transform infrared spectra (FTIR), contact angle, viability assay, and in vitro myelination by oligodendrocytes were characterized. The results showed that such fibers are bead-free and continuous, with an average size from 294 ± 53 to 390 ± 54 nm. The DSC and FTIR curves indicated no changes in the phase state of coaxial brackets. Hyaluronic acid/PLLA coaxial fibers had the minimum contact angle (53.1° ± 0.24°). Myelin sheaths were wrapped around a coaxial electrospun scaffold modified with water-soluble materials after a 14-day incubation. All results suggest that such a scaffold prepared by coaxial electrospinning potentially provides a novel platform for oligodendrocyte myelination.

Recent advances in development of nanomedicines for multiple sclerosis diagnosis

Multiple sclerosis (MS) is a neurodegenerative disease with a high morbidity and disease burden. It is characterized by the loss of the myelin sheath, resulting in the disruption of neuron electrical signal transmissions and sensory and motor ability deficits. The diagnosis of MS is crucial to its management, but the diagnostic sensitivity and specificity are always a challenge. To overcome this challenge, nanomedicines have recently been employed to aid the diagnosis of MS with an improved diagnostic efficacy. Advances in nanomedicine-based contrast agents in magnetic resonance imaging scanning of MS lesions, and nanomedicine-derived sensors for detecting biomarkers in the cerebrospinal fluid biopsy, or analyzing the composition of exhaled breath gas, have demonstrated the potential of using nanomedicines in the accurate diagnosis of MS. This review aims to provide an overview of recent advances in the application of nanomedicines for the diagnosis of MS and concludes with perspectives of using nanomedicines for the development of safe and effective MS diagnostic nanotools.

Brain metastasis models: What should we aim to achieve better treatments?

Brain metastasis is emerging as a unique entity in oncology based on its particular biology and, consequently, the pharmacological approaches that should be considered. We discuss the current state of modelling this specific progression of cancer and how these experimental models have been used to test multiple pharmacologic strategies over the years. In spite of pre-clinical evidences demonstrating brain metastasis vulnerabilities, many clinical trials have excluded patients with brain metastasis. Fortunately, this trend is getting to an end given the increasing importance of secondary brain tumors in the clinic and a better knowledge of the underlying biology. We discuss emerging trends and unsolved issues that will shape how we will study experimental brain metastasis in the years to come.

Nanotechnology shaping stem cell therapy: Recent advances, application, challenges, and future outlook

Currently, stem cell nanotechnology is one of the novel and exciting fields. Certain experimental studies conducted on the interaction of stem cells with nanostructures or nanomaterials have made significant progress. The significance of nanostructures, nanotechnology, and nanomaterials in the development of stem cell-based therapies for degenerative diseases and injuries has been well established. Specifically, the structure and properties of nanomaterials affecting the propagation and differentiation of stem cells have become a new interdisciplinary frontier in material science and regeneration medicines. In the current review, we highlight the recent major progress in this field, explore the application prospects, and discuss the issues, approaches, and challenges, to improve the applications of nanotechnology in the research and development of stem cells.

Are extracellular vesicles new hope in clinical drug delivery for neurological disorders?

Cells secrete extracellular vesicles (EVs) for intercellular communication. EVs are natural nanovesicles that are surrounded by lipid bilayer for delivery of assorted cargoes for therapeutic purposes. In addition to their therapeutic roles, these vesicles are potential drug delivery systems. Exosomes are the most studied EVs as the delivery carriers that can cross the blood-brain barrier (BBB) because of their nanosize. BBB is a diffusion barrier that is selective for small molecules to transit from blood to the brain. This barrier has been an obstacle for the delivery of drugs to the brain for the treatment of neurological disorders (NDs). For efficient drug delivery, synthetic vesicles such as liposomes have been employed as carriers for delivery of therapeutic molecules in clinical practice. However, these delivery systems are not without drawbacks. Among the limitations of these drug carriers include recognition by the body as foreign particles that encounter multiple defence systems that could recognize, neutralize and eliminate them. EVs are natural vesicles that may circumvent the body defence system to remain in systemic circulation for a long time. This unique property made them excellent drug delivery vehicles for clinical application. Here I discuss the progress, challenges and future directions of EVs (especially exosomes) as vehicles for targeted delivery of drug and at the same time deliver their cargoes for regenerative purposes in NDs. Recent developments in bioengineering and microfluidic technologies, which hold promise for clinical-grade production of EVs as drug delivery systems for NDs are also highlighted.

Glial restricted precursor delivery of dendrimer N-acetylcysteine promotes migration and differentiation following transplant in mouse white matter injury model

Oligodendrocyte replacement using glial restricted precursors (GRPs) is a promising avenue for the treatment of acquired or genetic white matter disorders; however, limited long-term survival of these cells post-transplant may impede maximal recovery. Nanotherapeutic approaches can facilitate stem cell delivery while simultaneously delivering factors aimed at enhancing and nourishing stem cells en route to, and at, the target site. Hydroxyl polyamidoamine (PAMAM) dendrimer nanoparticles have been used in a variety of models to deliver therapeutics in a targeted manner to injury sites at low doses. Here, survival and migration of GRPs was assessed in a mouse model of neonatal white matter injury with different methods of dendrimer nanoparticle support. Our findings demonstrate the ability of GRPs to take up nanoparticle-drug conjugates and for these conjugates to act beyond the injury site in vivo. Compared to GRPs alone, mice receiving dendrimer-drug in parallel to GRPs, or via GRPs as the delivery vector, showed improved migration and differentiation of cells 8 weeks post-transplant. These studies demonstrate that drug-conjugated nanoparticles can enhance transplanted progenitor cell survival and migration, and suggest that combination therapies may allow engraftment without overt immunosuppression.

Application of Nanotechnology in Stem-Cell-Based Therapy of Neurodegenerative Diseases

In addition to adverse health outcomes, neurological disorders have serious societal and economic impacts on patients, their family and society as a whole. There is no definite treatment for these disorders, and current available drugs only slow down the progression of the disease. In recent years, application of stem cells has been widely advanced due to their potential of self-renewal and differentiation to different cell types which make them suitable candidates for cell therapy. In particular, this approach offers great opportunities for the treatment of neurodegenerative disorders. However, some major issues related to stem-cell therapy, including their tumorigenicity, viability, safety, metastases, uncontrolled differentiation and possible immune response have limited their application in clinical scales. To address these challenges, a combination of stem-cell therapy with nanotechnology can be a solution. Nanotechnology has the potential of improvement of stem-cell therapy by providing ideal substrates for large scale proliferation of stem cells. Application of nanomaterial in stem-cell culture will be also beneficial to modulation of stem-cell differentiation using nanomedicines. Nanodelivery of functional compounds can enhance the efficiency of neuron therapy by stem cells and development of nanobased techniques for real-time, accurate and long-lasting imaging of stem-cell cycle processes. However, these novel techniques need to be investigated to optimize their efficiency in treatment of neurologic diseases.