Multifunctionalized CMCht/PAMAM dendrimer nanoparticles modulate the cellular uptake by astrocytes and oligodendrocytes in primary cultures of glial cells

Nano-based approaches for the treatment of neuro-immunological disorders: a special emphasis on multiple sclerosis

Multiple sclerosis (MS) is a neuroimmunological disorder which causes axonal damage, demyelination and paralysis. Although numerous therapeutics have been developed for the effective treatment of MS and a few have been approved in recent decades, complete remission and treatment of MS remain a matter of concern. Nanotechnology is a potential approach for manipulating the properties of materials at the molecular level to attain desired properties. This approach is effective in the treatment of several CNS disorders by enhancing drug delivery, bioavailability and efficacy. We have briefly discussed the neuroimmunological disorders with a particular emphasis on MS. We also explored nanoengineered drug delivery systems, describing several nano-formulations for the treatment of MS, challenges and future of nanotechnology.

A review: oligodendrocytes in neuronal axonal conduction and methods for enhancing their performance

OBJECTIVES

This review explores the vital role of oligodendrocytes in axon myelination and efficient neuronal transmission and the impact of dysfunction resulting from neurotransmitter deficiencies related disorders. Furthermore, the review also provides insight into the potential of bionanotechnology for addressing neurodegenerative diseases by targeting oligodendrocytes.

METHODS

A review of literature in the field was conducted using Google scholar. Systematic searches were performed to identify relevant studies and reviews addressing the role of oligodendrocytes in neural function, the influence of neurotransmitters on oligodendrocyte differentiation, and the potential of nanotechnology-based strategies for targeted therapy of oligodendrocytes.

RESULTS

This review indicates the mechanisms underlying oligodendrocyte differentiation and the influence of neurotransmitters on this process. The importance of action potentials and neurotransmission in neural function and the susceptibility of damaged nerve axons to ischemic or toxic damage is provided in detail. The potential of bionanotechnology for targeting neurodegenerative diseases using nanotechnology-based strategies, including polymeric, lipid-based, inorganic, organic, and biomimetic nanoparticles, suggests better management of neurodegenerative disorders.

CONCLUSION

While nanotechnology-based biomaterials show promise for targeted oligodendrocyte therapy in addressing neurodegenerative disorders linked to oligodendrocyte dysfunction, encapsulating neuroprotective agents within nanoparticles offers additional advantages. Nano-based delivery systems effectively protect drugs from degradation and prolong their therapeutic effects, holding promise in overcoming the blood-brain barrier by facilitating drug transport. However, a multifaceted approach is essential to enhance oligodendrocyte differentiation, promote myelin repair, and facilitate myelin dynamics with reduced toxicity. Further research is needed to elucidate the optimal therapeutic approaches and enhance patient outcomes.

Recent advancements in nanoparticle-mediated approaches for restoration of multiple sclerosis

Multiple Sclerosis (MS) is an autoimmune disease with complicated immunopathology which necessitates considering multifactorial aspects for its management. Nano-sized pharmaceutical carriers named nanoparticles (NPs) can support impressive management of disease not only in early detection and prognosis level but also in a therapeutic manner. The most prominent initiator of MS is the domination of cellular immunity to humoral immunity and increment of inflammatory cytokines. The administration of several platforms of NPs for MS management holds great promise so far. The efforts for MS management through in vitro and in vivo (experimental animal models) evaluations, pave a new way to a highly efficient therapeutic means and aiding its translation to the clinic in the near future.

Neuroinflammation Treatment via Targeted Delivery of Nanoparticles

The lack of effective treatments for most neurological diseases has prompted the search for novel therapeutic options. Interestingly, neuroinflammation is emerging as a common feature to target in most CNS pathologies. Recent studies suggest that targeted delivery of small molecules to reduce neuroinflammation can be beneficial. However, suboptimal drug delivery to the CNS is a major barrier to modulate inflammation because neurotherapeutic compounds are currently being delivered systemically without spatial or temporal control. Emerging nanomaterial technologies are providing promising and superior tools to effectively access neuropathological tissue in a controlled manner. Here we highlight recent advances in nanomaterial technologies for drug delivery to the CNS. We propose that state-of-the-art nanoparticle drug delivery platforms can significantly impact local CNS bioavailability of pharmacological compounds and treat neurological diseases.

Pharmacological targets of metabolism in disease: Opportunities from macrophages

From advances in the knowledge of the immune system, it is emerging that the specialized functions displayed by macrophages during the course of an immune response are supported by specific and dynamically-connected metabolic programs. The study of immunometabolism is demonstrating that metabolic adaptations play a critical role in modulating inflammation and, conversely, inflammation deeply influences the acquisition of specific metabolic settings.This strict connection has been proven to be crucial for the execution of defined immune functional programs and it is now under investigation with respect to several human disorders, such as diabetes, sepsis, cancer, and autoimmunity. The abnormal remodelling of the metabolic pathways in macrophages is now emerging as both marker of disease and potential target of therapeutic intervention. By focusing on key pathological conditions, namely obesity and diabetes, rheumatoid arthritis, atherosclerosis and cancer, we will review the metabolic targets suitable for therapeutic intervention in macrophages. In addition, we will discuss the major obstacles and challenges related to the development of therapeutic strategies for a pharmacological targeting of macrophage's metabolism.

Highly selective microglial uptake of ceria-zirconia nanoparticles for enhanced analgesic treatment of neuropathic pain

Neuropathic pain is a chronic and pathological pain caused by injury or dysfunction in the nervous system. Pro-inflammatory microglial activation with aberrant reactive oxygen species (ROS) generation in the spinal cord plays a critical role in the development of neuropathic pain. However, the efficacy of current therapeutic methods for neuropathic pain is limited because only neurons or neural circuits involved in pain transmission are targeted. Here, an effective strategy to treat pain hypersensitivity using microglia-targeting ceria-zirconia nanoparticles (CZ NPs) is reported. The CZ NPs are coated with microglia-specific antibodies to promote their delivery to microglia, and thus to improve their therapeutic efficacy. The targeted delivery facilitates the elimination of both pro-inflammatory cytokines and ROS in microglia, enabling the rapid and effective inhibition of microglial activation. As a result, greatly ameliorated mechanical allodynia is achieved in a spinal nerve transection (SNT)-induced neuropathic pain mouse model, proving the potent analgesic effect of the microglia-targeting CZ NPs. Given the generality of the approach used in this study, the microglia-targeting CZ NPs are expected to be useful for the treatment of not only neuropathic pain but also other neurological diseases associated with the vicious activation of microglia.

Nanomodulation of Macrophages in Multiple Sclerosis

Multiple Sclerosis (MS) is a chronic demyelinating autoimmune disease primarily affecting young adults. Despite an unclear causal factor, symptoms and pathology arise from the infiltration of peripheral immune cells across the blood brain barrier. Accounting for the largest fraction of this infiltrate, macrophages are functionally heterogeneous innate immune cells capable of adopting either a pro or an anti-inflammatory phenotype, a phenomenon dependent upon cytokine milieu in the CNS. This functional plasticity is of key relevance in MS, where the pro-inflammatory state dominates the early stage, instructing demyelination and axonal loss while the later anti-inflammatory state holds a key role in promoting tissue repair and regeneration in later remission. This review highlights a potential therapeutic benefit of modulating macrophage polarisation to harness the anti-inflammatory and reparative state in MS. Here, we outline the role of macrophages in MS and look at the role of current FDA approved therapeutics in macrophage polarisation. Moreover, we explore the potential of particulate carriers as a novel strategy to manipulate polarisation states in macrophages, whilst examining how optimising macrophage uptake via nanoparticle size and functionalisation could offer a novel therapeutic approach for MS.

Nanovector-Mediated Drug Delivery in Spinal Cord Injury: A Multitarget Approach

Many preclinical studies seek cures for spinal cord injury (SCI), but when the results are translated to clinical trials they give scant efficacy. One possible reason is that most strategies use treatments directed toward a single pathological mechanism, while a multitherapeutic approach needs to be tested to significantly improve outcomes after SCI. Most of the preclinical reports gave better outcomes when a combination of different compounds was used instead of a single drug. This promising approach, however, must still be improved because it raises some criticism: (i) the blood-spinal cord barrier limits drug distribution, (ii) it is hard to understand the interactions among the pharmacological components after systemic administration, and (iii) the timing of treatments is crucial: the spread of the lesion is a process finely regulated over time, so therapies must be scheduled at precise times during the postinjury course. Nanomedicine could be useful to overcome these limitations. Nanotools allow finely regulated drug administration in terms of cell selectivity and release kinetics. We believe that excellent therapeutic results could be obtained by exploiting this tool in multitherapy. Combining nanoparticles loaded with different compounds that act on the main pathological pathways could overcome the restrictions of traditional drug delivery routes, a major limit for the clinical application of multitherapy. This review digs into these topics, discussing the critical aspects of multitherapies now proposed and suggesting new points of view.

The uptake, retention and clearance of drug-loaded dendrimer nanoparticles in astrocytes – electrophysiological quantification

Endocytosed dendrimer nanoparticles (NPs) are cleared from the astrocytes by an increased rate of transient exocytotic fusion events.

Prevention of Synaptic Alterations and Neurotoxic Effects of PAMAM Dendrimers by Surface Functionalization

One of the most studied nanocarriers for drug delivery are polyamidoamine (PAMAM) dendrimers. However, the alterations produced by PAMAM dendrimers in neuronal function have not been thoroughly investigated, and important aspects such as effects on synaptic transmission remain unexplored. We focused on the neuronal activity disruption induced by dendrimers and the possibility to prevent these effects by surface chemical modifications. Therefore, we studied the effects of fourth generation PAMAM with unmodified positively charged surface (G4) in hippocampal neurons, and compared the results with dendrimers functionalized in 25% of their surface groups with folate (PFO₂₅) and polyethylene glycol (PPEG₂₅). G4 dendrimers significantly reduced cell viability at 1 µM, which was attenuated by both chemical modifications, PPEG₂₅ being the less cytotoxic. Patch clamp recordings demonstrated that G4 induced a 7.5-fold increment in capacitive currents as a measure of membrane permeability. Moreover, treatment with this dendrimer increased intracellular Ca²⁺ by 8-fold with a complete disruption of transients pattern, having as consequence that G4 treatment increased the synaptic vesicle release and frequency of synaptic events by 2.4- and 3-fold, respectively. PFO₂₅ and PPEG₂₅ treatments did not alter membrane permeability, total Ca²⁺ intake, synaptic vesicle release or synaptic activity frequency. These results demonstrate that cationic G4 dendrimers have neurotoxic effects and induce alterations in normal synaptic activity, which are generated by the augmentation of membrane permeability and a subsequent intracellular Ca²⁺ increase. Interestingly, these toxic effects and synaptic alterations are prevented by the modification of 25% of PAMAM surface with either folate or polyethylene glycol.

Blocked, delayed, or obstructed: What causes poor white matter development in intrauterine growth restricted infants?

Poor white matter development in intrauterine growth restricted (IUGR) babies remains a major, untreated problem in neonatology. New therapies, guided by an understanding of the mechanisms that underlie normal and abnormal oligodendrocyte development and myelin formation, are required. Much of our knowledge of the mechanisms that underlie impaired myelination come from studies in adult demyelinating disease, preterm brain injury, or experimental models of hypoxia-ischemia. However, relatively less is known for IUGR which is surprising because IUGR is a leading cause of perinatal mortality and morbidity, second only to premature birth. IUGR is also a significant risk factor for the later development of cerebral palsy, and is a greater risk compared to some of the more traditionally researched antecedents - asphyxia and inflammation. Recent evidence suggests that the white matter injury and reduced myelination in the brains of some preterm babies is due to impaired maturation of oligodendrocytes thereby resulting in the reduced capacity to synthesize myelin. Therefore, it is not surprising that the hypomyelination observable in the central nervous system of IUGR infants has similarly lead to investigations identifying a delay or blockade in the progress of maturation of oligodendrocytes in these infants. This review will discuss current ideas thought to account for the poor myelination often present in the neonate's brain following IUGR, and discuss novel interventions that are promising as treatments that promote oligodendrocyte maturation, and thereby repair the myelination deficits that otherwise persist into infancy and childhood and lead to neurodevelopmental abnormalities.

Nanomedicine in Central Nervous System (CNS) Disorders: A Present and Future Prospective

Purpose: For the past few decades central nervous system disorders were considered as a major strike on human health and social system of developing countries. The natural therapeutic methods for CNS disorders limited for many patients. Moreover, nanotechnology-based drug delivery to the brain may an exciting and promising platform to overcome the problem of BBB crossing. In this review, first we focused on the role of the blood-brain barrier in drug delivery; and second, we summarized synthesis methods of nanomedicine and their role in different CNS disorder. Method: We reviewed the PubMed databases and extracted several kinds of literature on neuro nanomedicines using keywords, CNS disorders, nanomedicine, and nanotechnology. The inclusion criteria included chemical and green synthesis methods for synthesis of nanoparticles encapsulated drugs and, their in-vivo and in-vitro studies. We excluded nanomedicine gene therapy and nanomaterial in brain imaging. Results: In this review, we tried to identify a highly efficient method for nanomedicine synthesis and their efficacy in neuronal disorders. SLN and PNP encapsulated drugs reported highly efficient by easily crossing BBB. Although, these neuro-nanomedicine play significant role in therapeutics but some metallic nanoparticles reported the adverse effect on developing the brain. Conclusion: Although impressive advancement has made via innovative potential drug development, but their efficacy is still moderate due to limited brain permeability. To overcome this constraint,powerful tool in CNS therapeutic intervention provided by nanotechnology-based drug delivery methods. Due to its small and biofunctionalization characteristics, nanomedicine can easily penetrate and facilitate the drug through the barrier. But still, understanding of their toxicity level, optimization and standardization are a long way to go.

Targeting specific cells in the brain with nanomedicines for CNS therapies

Treatment of Central Nervous System (CNS) disorders still remains a major clinical challenge. The Blood-Brain Barrier (BBB), known as the major hindrance, greatly limits therapeutics penetration into the brain. Moreover, even though some therapeutics can cross BBB based on their intrinsic properties or via the use of proper nanoscale delivery vehicles, their therapeutic efficacy is still often limited without the specific uptake of drugs by the cancer or disease-associated cells. As more studies have started to elucidate the pathological roles of major cells in the CNS (for example, microglia, neurons, and astrocytes) for different disorders, nanomedicines that can enable targeting of specific cells in these diseases may provide great potential to boost efficacy. In this review, we aim to briefly cover the pathological roles of endothelial cells, microglia, tumor-associated microglia/macrophage, neurons, astrocytes, and glioma in CNS disorders and to highlight the recent advances in nanomedicines that can target specific disease-associated cells. Furthermore, we summarized some strategies employed in nanomedicine to achieve specific cell targeting or to enhance the drug neuroprotective effects in the CNS. The specific targeting at the cellular level by nanotherapy can be a more precise and effective means not only to enhance the drug availability but also to reduce side effects.

Smart polymeric nanoparticles for cancer gene delivery

The massive amount of human genetic information already available has accelerated the identification of target genes, making gene and nucleic acid therapy the next generation of medicine. Nanoparticle (NP)-based anticancer gene therapy treatment has received significant interest in this evolving field. Recent advances in vector technology have improved gene transfection efficiencies of nonviral vectors to a level similar to viruses. This review serves as an introduction to surface modifications of NPs based on polymeric structural improvements and target moieties. A discussion regarding the future perspective of multifunctional NPs in cancer therapy is also included.

Lipocalin 2 modulates the cellular response to amyloid beta

The production, accumulation and aggregation of amyloid beta (Aβ) peptides in Alzheimer's disease (AD) are influenced by different modulators. Among these are iron and iron-related proteins, given their ability to modulate the expression of the amyloid precursor protein and to drive Aβ aggregation. Herein, we describe that lipocalin 2 (LCN2), a mammalian acute-phase protein involved in iron homeostasis, is highly produced in response to Aβ1-42 by choroid plexus epithelial cells and astrocytes, but not by microglia or neurons. Although Aβ1-42 stimulation decreases the dehydrogenase activity and survival of wild-type astrocytes, astrocytes lacking the expression of Lcn2 are not affected. This protection results from a lower expression of the proapoptotic gene Bim and a decreased inflammatory response. Altogether, these findings show that Aβ toxicity to astrocytes requires LCN2, which represents a novel mechanism to target when addressing AD.

BioMEMS in drug delivery

The drive to design micro-scale medical devices which can be reliably and uniformly mass produced has prompted many researchers to adapt processing technologies from the semiconductor industry. By operating at a much smaller length scale, the resulting biologically-oriented microelectromechanical systems (BioMEMS) provide many opportunities for improved drug delivery: Low-dose vaccinations and painless transdermal drug delivery are possible through precisely engineered microneedles which pierce the skin's barrier layer without reaching the nerves. Low-power, low-volume BioMEMS pumps and reservoirs can be implanted where conventional pumping systems cannot. Drug formulations with geometrically complex, extremely uniform micro- and nano-particles are formed through micromolding or with microfluidic devices. This review describes these BioMEMS technologies and discusses their current state of implementation. As these technologies continue to develop and capitalize on their simpler integration with other MEMS-based systems such as computer controls and telemetry, BioMEMS' impact on the field of drug delivery will continue to increase.

Multifunctional nanoparticles for targeted delivery of immune activating and cancer therapeutic agents

Nanoparticles (NPs) have been extensively investigated for applications in both experimental and clinical settings to improve delivery efficiency of therapeutic and diagnostic agents. Most recently, novel multifunctional nanoparticles have attracted much attention because of their ability to carry diverse functionalities to achieve effective synergistic therapeutic treatments. Multifunctional NPs have been designed to co-deliver multiple components, target the delivery of drugs by surface functionalization, and realize therapy and diagnosis simultaneously. In this review, various materials of diverse chemistries for fabricating multifunctional NPs with distinctive architectures are discussed and compared. Recent progress involving multifunctional NPs for immune activation, anticancer drug delivery, and synergistic theranostics is the focus of this review. Overall, this comprehensive review demonstrates that multifunctional NPs have distinctive properties that make them highly suitable for targeted therapeutic delivery in these areas.

Microglia response and in vivo therapeutic potential of methylprednisolone-loaded dendrimer nanoparticles in spinal cord injury

The control and manipulation of cells that trigger secondary mechanisms following spinal cord injury (SCI) is one of the first opportunities to minimize its highly detrimental outcomes. Herein, the ability of surface-engineered carboxymethylchitosan/polyamidoamine (CMCht/PAMAM) dendrimer nanoparticles to intracellularly deliver methylprednisolone (MP) to glial cells, allowing a controlled and sustained release of this corticosteroid in the injury site, is investigated. The negatively charged MP-loaded CMCht/PAMAM dendrimer nanoparticles with sizes of 109 nm enable a MP sustained release, which is detected for a period of 14 days by HPLC. In vitro studies in glial primary cultures show that incubation with 200 μg mL(-1) nanoparticles do not affect the cells' viability or proliferation, while allowing the entire population to internalize the nanoparticles. At higher concentrations, microglial cell viability is proven to be affected in response to the MP amount released. Following lateral hemisection lesions in rats, nanoparticle uptake by the spinal tissue is observed 3 h after administration. Moreover, significant differences in the locomotor output between the controls and the MP-loaded nanoparticle-treated animals one month after the lesion are observed. Therefore, MP-loaded CMCht/PAMAM dendrimer nanoparticles may prove to be useful in the reduction of the secondary injury following SCI.