PLGA-Based Nanoparticles for Neuroprotective Drug Delivery in Neurodegenerative Diseases

Preparation and Characterization of Mitochondrial-Targeted Nitronyl Nitroxide Loaded PLGA Nanoparticles for Brain Injury Induced by Hypobaric Hypoxia in Mice

Background

Oxidative stress is considered an important mechanism of acute high-altitude brain injury. Imidazole nitronyl nitroxide radicals are a class of stable organic radical scavengers that contain single electrons in their molecules. Therefore, in order to search for compounds with low toxicity and better effect against high-altitude brain injury, the preparation methods of PLGA nanoparticles (TPP-C6-HPN@PLGA-NPs) loaded with a synthesized mitochondria targeting imidazole nitronyl nitroxide were emphasized and investigated. Furthermore, its protective effect on brain injury caused by low-pressure hypoxia (HH) in mice was evaluated.

Methods

Nanoparticles were prepared by emulsion solvent evaporation method, and the preparation method was optimized by Box Behnken design based on particle size, encapsulation efficiency (EE) and drug loading (DL). Physical characterization and release studies of the optimized NPs were conducted. The high altitude brain injury mice model was selected to evaluate the therapeutic effect of TPP-C6-HPN@PLGA-NPs in vivo. The histological and biochemical tests were conducted in serum and brain of mice exposed to HH condition.

Results

The nanoparticle size was 120.63 nm, the EE was 89.30%, the DL was 6.82%, the polydispersity index (PDI) was 0.172, and the zeta potential was -22.67 mV under optimal preparation process. In addition, TPP-C6-HPN@PLGA-NPs owned good stabilities and sustained drug releases. TPP-C6-HPN@PLGA-NP exhibited lower toxicity than TPP-C6-HPN and was well uptaken by PC12 cells. Histological and biochemical analysis demonstrated that TPP-C6-HPN@PLGA-NPs significantly reduced HH induced pathological lesions, oxidative stress, energy dysfunction and inflammation response of brain tissue. Furthermore, nanoparticles did not show significant toxicity to major organs such as the liver and kidneys, as well as hematology in mice.

Conclusion

TPP-C6-HPN@PLGA-NPs exhibits good stability, low hemolysis rate, sustained release, low toxicity, and long residence time in brain tissue and can be used as a promising formulation for the proper treatment of HH-induced brain damage.

From Molecules to Mind: The Critical Role of Chitosan, Collagen, Alginate, and Other Biopolymers in Neuroprotection and Neurodegeneration

Neurodegenerative disorders present significant therapeutic challenges, particularly due to the complex nature of drug delivery to the central nervous system. This review investigates the applications of various biopolymers in neuroprotection and their potential role in treating neurodegeneration. We present a critical analysis of natural and synthetic biopolymers, focusing primarily on chitosan, fish collagen/gelatin, and alginate as key therapeutic agents. The review examines the fundamental mechanisms of brain development and neurodegeneration, establishing a framework for understanding how these biopolymers interact with neural tissues. By analyzing recent experimental studies, we evaluate the effectiveness of different biopolymer-based delivery systems in crossing the blood-brain barrier and their subsequent neuroprotective effects. Additionally, promising materials, including lignin, poly lactic-co-glycolic acid, and glucose-modified bovine serum albumin/procyanidin complexes, are briefly explored to provide a comprehensive overview of current developments in the field. Our analysis reveals that biopolymer-based approaches offer unique advantages in both neuroprotection and drug delivery, potentially opening new avenues for treating neurodegenerative conditions. This review synthesizes current knowledge and identifies promising directions for future research in biopolymer-based therapeutic strategies.

Nanomaterials-mediated lysosomal regulation: a robust protein-clearance approach for the treatment of Alzheimer's disease

Alzheimer's disease is a debilitating, progressive neurodegenerative disorder characterized by the progressive accumulation of abnormal proteins, including amyloid plaques and intracellular tau tangles, primarily within the brain. Lysosomes, crucial intracellular organelles responsible for protein degradation, play a key role in maintaining cellular homeostasis. Some studies have suggested a link between the dysregulation of the lysosomal system and pathogenesis of neurodegenerative diseases, including Alzheimer's disease. Restoring the normal physiological function of lysosomes hold the potential to reduce the pathological burden and improve the symptoms of Alzheimer's disease. Currently, the efficacy of drugs in treating Alzheimer's disease is limited, with major challenges in drug delivery efficiency and targeting. Recently, nanomaterials have gained widespread use in Alzheimer's disease drug research owing to their favorable physical and chemical properties. This review aims to provide a comprehensive overview of recent advances in using nanomaterials (polymeric nanomaterials, nanoemulsions, and carbon-based nanomaterials) to enhance lysosomal function in treating Alzheimer's disease. This review also explores new concepts and potential therapeutic strategies for Alzheimer's disease through the integration of nanomaterials and modulation of lysosomal function. In conclusion, this review emphasizes the potential of nanomaterials in modulating lysosomal function to improve the pathological features of Alzheimer's disease. The application of nanotechnology to the development of Alzheimer's disease drugs brings new ideas and approaches for future treatment of this disease.

Enhanced anti-inflammatory and anti-fibrotic effects of nanoparticles loaded with a combination of Aloe vera-Moringa oleifera extracts

Metabolic associated steatohepatitis characterized by lipid accumulation, inflammation and fibrosis, is a growing global health issue, contributing to severe liver-related mortality. With limited effective treatments available, there is an urgent need for novel therapeutic strategies. Moringa oleifera, rich in antioxidants, offers potential for combating steatohepatitis, but its cytotoxicity presents challenges. Aloe vera, renowned for its cytocompatibility and anti-inflammatory effects, shows promise in mitigating these risks. Using infrared spectrometry and mass spectrometry, we identified 1586 metabolites from both plants across 84 chemical classes. By encapsulating these phytochemicals in nanoparticles, we achieved increased solubility, cytocompatibility, and gene modulation to hepatic stellate cells affected by steatohepatitis. Chemoinformatic analysis revealed bioactive metabolites, including hesperetin analogs, known to inhibit TGF-β. Our results demonstrate that these nanoparticles not only improved gene expression modulation related to metabolic associated steatohepatitis, particularly TGF-β and COL1A1, but also outperformed free compounds, highlighting their potential as a novel therapeutic approach.

The micro(nano)plastics perspective: exploring cancer development and therapy

Microplastics, as an emerging environmental pollutant, have received widespread attention for their potential impact on ecosystems and human health. Microplastics are defined as plastic particles less than 5 millimeters in diameter and can be categorized as primary and secondary microplastics. Primary microplastics usually originate directly from industrial production, while secondary microplastics are formed by the degradation of larger plastic items. Microplastics are capable of triggering cytotoxicity and chronic inflammation, and may promote cancer through mechanisms such as pro-inflammatory responses, oxidative stress and endocrine disruption. In addition, improved microplastics bring new perspectives to cancer therapy, and studies of microplastics as drug carriers are underway, showing potential for high targeting and bioavailability. Although current studies suggest an association between microplastics and certain cancers (e.g., lung, liver, and breast cancers), the long-term effects and specific mechanisms still need to be studied. This review aimed at exploring the carcinogenicity of microplastics and their promising applications in cancer therapy provides important directions for future research and emphasizes the need for multidisciplinary collaboration to address this global health challenge.

Promising breakthroughs in amyotrophic lateral sclerosis treatment through nanotechnology's unexplored frontier

This review explores the transformative potential of nanotechnology in the treatment and diagnosis of amyotrophic lateral sclerosis (ALS), a progressive neurodegenerative disorder characterized by motor neuron degeneration, muscle weakness, and eventual paralysis. Nanotechnology offers innovative solutions across various domains, including targeted drug delivery, neuroprotection, gene therapy and editing, biomarker detection, advanced imaging techniques, and tissue engineering. By enhancing the precision and efficacy of therapeutic interventions, nanotechnology facilitates key advancements such as crossing the blood-brain barrier, targeting specific cell types, achieving sustained therapeutic release, and enabling combination therapies tailored to the complex pathophysiology of ALS. Despite its immense promise, the clinical translation of these approaches faces challenges, including potential cytotoxicity, biocompatibility, and regulatory compliance, which must be addressed through rigorous research and testing. This review emphasizes the application of nanotechnology in targeted drug delivery and gene therapy/editing for ALS, drawing on the author's prior work with various nanotechnological platforms to illustrate strategies for overcoming similar obstacles in drug and gene delivery. By bridging the gap between cutting-edge technology and clinical application, this article aims to highlight the vital role of nanotechnology in shaping the future of ALS treatment.

Epilepsy Treatment and Diagnosis Enhanced by Current Nanomaterial Innovations: A Comprehensive Review

Epilepsy is a complex disease in the brain. Complete control of seizure has always been a challenge in epilepsy treatment. Currently, clinical management primarily involves pharmacological and surgical interventions, with the former being the preferred approach. However, antiepileptic drugs often exhibit low bioavailability due to inherent limitations such as poor water solubility and difficulty penetrating the blood-brain barrier (BBB). These issues significantly reduce the drugs' effectiveness and limit their clinical application in epilepsy treatment. Additionally, the diagnostic accuracy of current imaging techniques and electroencephalography (EEG) for epilepsy is suboptimal, often failing to precisely localize epileptogenic tissues. Accurate diagnosis is critical for the surgical management of epilepsy. Thus, there is a pressing need to enhance both the therapeutic outcomes of epilepsy medications and the diagnostic precision of the condition. In recent years, the advancement of nanotechnology in the biomedical sector has led to the development of nanomaterials as drug carriers. These materials are designed to improve drug bioavailability and targeting by leveraging their large specific surface area, facile surface modification, ability to cross the BBB, and high biocompatibility. Furthermore, nanomaterials have been utilized as contrast agents in imaging and as materials for EEG electrodes, enhancing the accuracy of epilepsy diagnoses. This review provides a comprehensive examination of current research on nanomaterials in the treatment and diagnosis of epilepsy, offering new strategies and directions for future investigation.

Effects of nanoparticle size, shape, and zeta potential on drug delivery

Nanotechnology has brought about a significant revolution in drug delivery, and research in this domain is increasingly focusing on understanding the role of nanoparticle (NP) characteristics in drug delivery efficiency. First and foremost, we center our attention on the size of nanoparticles. Studies have indicated that NP size significantly influences factors such as circulation time, targeting capabilities, and cellular uptake. Secondly, we examine the significance of nanoparticle shape. Various studies suggest that NPs of different shapes affect cellular uptake mechanisms and offer potential advantages in directing drug delivery. For instance, cylindrical or needle-like NPs may facilitate better cellular uptake compared to spherical NPs. Lastly, we address the importance of nanoparticle charge. Zeta potential can impact the targeting and cellular uptake of NPs. Positively charged NPs may be better absorbed by negatively charged cells, whereas negatively charged NPs might perform more effectively in positively charged cells. This review provides essential insights into understanding the role of nanoparticles in drug delivery. The properties of nanoparticles, including size, shape, and charge, should be taken into consideration in the rational design of drug delivery systems, as optimizing these characteristics can contribute to more efficient targeting of drugs to the desired tissues. Thus, research into nanoparticle properties will continue to play a crucial role in the future of drug delivery.

Conjugation of Antibodies and siRNA Duplexes to Polymer Nanoparticles via Maleimide-Thiol Chemistry

Polymeric nanoparticles (NPs) have shown great promise as highly modifiable platforms that can be applied across many different disease states. They are advantageous because they can encapsulate a range of hydrophobic and hydrophilic cargoes while having customizable surface properties. Depending on the desired biointerfacing capabilities, the surface of polymeric NPs can be modified with moieties, such as antibodies, peptides, nucleic acids, and more. The work presented here is intended to provide mechanistic insight into how different parameters influence the loading of antibodies, small interfering ribonucleic acids (siRNAs), or both on the surface of poly(lactic-co-glycolic acid) (PLGA) NPs via maleimide-thiol chemistry. Some of the conjugation parameters investigated include the buffer concentration, maleimide to protein ratio, and the addition of an excipient such as Tween-20. Through variation in the concentration of FZD7 antibodies added to the reaction mixture, we established tunable conjugation and found the upper limit of their loading density under the conditions tested. We also confirmed antibody conjugation through two different mechanisms: via a thiol-modified antibody or a thiol-modified poly(ethylene glycol) (PEG) linker. Conjugation of thiolated siRNA duplexes targeting β-catenin was also investigated through variations in both Tween-20 concentration and CaCl2 buffer concentration. Finally, the coconjugation of both antibodies and siRNA duplexes was explored. Overall, this work outlines a basis for tunable biomolecule loading on polymer NPs using maleimide-thiol chemistry and reveals the incredible versatility of polymer NP platforms.

Auranofin-loaded PLGA nanoparticles alleviate cognitive deficit induced by streptozotocin in rats model: modulation of oxidative stress, neuroinflammatory markers, and neurotransmitters

Alzheimer's disease remains an unsolved neurological puzzle with no cure. Current therapies offer only symptomatic relief, hindered by limited uptake through the blood-brain barrier. Auranofin, an FDA-approved compound, exhibits potent antioxidative and anti-inflammatory properties targeting brain disorders. Yet, its oral bioavailability challenge prompts the exploration of nanoformulation-based solutions enhancing blood-brain barrier penetrability. The study aimed to investigate the neuroprotective potential of auranofin nanoparticles in streptozotocin-induced AD rats. Auranofin-containing polylactic-co-glycolic acid nanoparticles were formulated by the multiple emulsion solvent evaporation method. Characterization was done by determining entrapment efficiency, particle size distribution, surface charge, and morphology. An in vivo study was performed by administering streptozotocin (3 mg/kg/i.c.v., days 1 and 3), auranofin (5 and 10 mg/kg), auranofin nanoparticles (2.5 and 5 mg/kg), and donepezil (2 mg/kg) for 14 days orally. Behavioral deficits were evaluated using the open field test, Morris water maze, objective recognition test, change in oxidative stress levels, and AD markers in the brain. Following the decapitation of the rats, the brains were excised to isolate the hippocampus. Subsequent analyses included the quantification of biochemical and neuroinflammatory markers, as well as the assessment of neurotransmitter levels. The characterization of auranofin nanoparticles showed an entrapment efficiency of 98%, an average particle size of 101.5 ± 10.3 nm, a surface charge of 27.5 ± 5.10 mV, and a polydispersity index of 0.438 ± 0.12. In vivo, administration of auranofin and auranofin nanoparticles significantly reversed streptozotocin-induced cognitive deficits, biochemical alteration, neuroinflammatory markers, and neurotransmitter levels. The present finding suggests that auranofin nanoparticles have more significant neuroprotective potential than auranofin alone. The therapeutic efficacy may be attributed to its antioxidant and anti-inflammatory properties, as well as its positive neuromodulatory effects. Therefore, our findings suggest that it could be a promising candidate for Alzheimer's disease therapy.

Serum-derived protein coronas affect nanoparticle interactions with brain cells

Neuronanomedicine is an emerging field bridging the gap between neuromedicine and novel nanotherapeutics. Despite promise, clinical translation of neuronanomedicine remains elusive, possibly due to a dearth of information regarding the effect of the protein corona on these neuronanomedicines. The protein corona, a layer of proteins adsorbed to nanoparticles following exposure to biological fluids, ultimately determines the fate of nanoparticles in biological systems, dictating nanoparticle-cell interactions. To date, few studies have investigated the effect of the protein corona on interactions with brain-derived cells, an important consideration for the development of neuronanomedicines. Here, two polymeric nanoparticles, poly(lactic-co-glycolic acid) (PLGA) and PLGA-polyethylene glycol (PLGA-PEG), were used to obtain serum-derived protein coronas. Protein corona characterization and liquid chromatography mass spectrometry analysis revealed distinct differences in biophysical properties and protein composition. PLGA protein coronas contained high abundance of globins (60%) and apolipoproteins (21%), while PLGA-PEG protein coronas contained fewer globins (42%) and high abundance of protease inhibitors (28%). Corona coated PLGA nanoparticles were readily internalized into microglia and neuronal cells, but not into astrocytes. Internalization of nanoparticles was associated with pro-inflammatory cytokine release and decreased neuronal cell viability, however, viability was rescued in cells treated with corona coated nanoparticles. These results showcase the importance of the protein corona in mediating nanoparticle-cell interactions.

Nanotechnology-driven therapies for neurodegenerative diseases: a comprehensive review

Neurological diseases, characterized by neuroinflammation and neurodegeneration, impose a significant global burden, contributing to substantial morbidity, disability and mortality. A common feature of these disorders, including stroke, traumatic brain injury and Alzheimer's disease, is the impairment of the blood-brain barrier (BBB), a critical structure for maintaining brain homeostasis. The compromised BBB in neurodegenerative conditions poses a significant challenge for effective treatment, as it allows harmful substances to accumulate in the brain. Nanomedicine offers a promising approach to overcoming this barrier, with nanoparticles (NPs) engineered to deliver therapeutic agents directly to affected brain regions. This review explores the classification and design of NPs, divided into organic and inorganic categories and further categorized based on their chemical and physical properties. These characteristics influence the ability of NPs to carry and release therapeutic agents, target specific tissues and ensure appropriate clearance from the body. The review emphasizes the potential of NPs to enhance the diagnosis and treatment of neurodegenerative diseases through targeted delivery, improved drug bioavailability and real-time therapeutic efficacy monitoring. By addressing the challenges of the compromised BBB and targeting inflammatory biomarkers, NPs represent a cutting-edge strategy in managing neurological disorders, promising better patient outcomes.

Biodegradable Polymeric Nanoparticle-Based Drug Delivery Systems: Comprehensive Overview, Perspectives and Challenges

In the last few decades, there has been a growing interest in the use of biodegradable polymeric nanoparticles (BPNPs) as the carriers for various therapeutic agents in drug delivery systems. BPNPs have the potential to improve the efficacy of numerous active agents by facilitating targeted delivery to a desired site in the body. Biodegradable polymers are especially promising nanocarriers for therapeutic substances characterized by poor solubility, instability, rapid metabolism, and rapid system elimination. Such molecules can be efficiently encapsulated and subsequently released from nanoparticles, which greatly improves their stability and bioavailability. Biopolymers seem to be the most suitable candidates to be used as the nanocarriers in various delivery platforms, especially due to their biocompatibility and biodegradability. Other unique properties of the polymeric nanocarriers include low cost, flexibility, stability, minimal side effects, low toxicity, good entrapment potential, and long-term and controlled drug release. An overview summarizing the research results from the last years in the field of the successful fabrication of BPNPs loaded with various therapeutic agents is provided. The possible challenges involving nanoparticle stability under physiological conditions and the possibility of scaling up production while maintaining quality, as well as the future possibilities of employing BPNPs, are also reviewed.

Breaking Barriers in Alzheimer's Disease: the Role of Advanced Drug Delivery Systems

Alzheimer's disease (AD), characterized by cognitive impairment, brain plaques, and tangles, is a global health concern affecting millions. It involves the build-up of amyloid-β (Aβ) and tau proteins, the formation of neuritic plaques and neurofibrillary tangles, cholinergic system dysfunction, genetic variations, and mitochondrial dysfunction. Various signaling pathways and metabolic processes are implicated in AD, along with numerous biomarkers used for diagnosis, risk assessment, and research. Despite these, there is no cure or effective treatment for AD. It is critically important to address this immediately to develop novel drug delivery systems (NDDS) capable of targeting the brain and delivering therapeutic agents to modulate the pathological processes of AD. This review summarizes AD, its pathogenesis, related signaling pathways, biomarkers, conventional treatments, the need for NDDS, and their application in AD treatment. It also covers preclinical, clinical, and ongoing trials, patents, and marketed AD formulations.

V-ATPase Dysfunction in the Brain: Genetic Insights and Therapeutic Opportunities

Vacuolar-type ATPase (v-ATPase) is a multimeric protein complex that regulates H+ transport across membranes and intra-cellular organelle acidification. Catabolic processes, such as endocytic degradation and autophagy, strictly rely on v-ATPase-dependent luminal acidification in lysosomes. The v-ATPase complex is expressed at high levels in the brain and its impairment triggers neuronal dysfunction and neurodegeneration. Due to their post-mitotic nature and highly specialized function and morphology, neurons display a unique vulnerability to lysosomal dyshomeostasis. Alterations in genes encoding subunits composing v-ATPase or v-ATPase-related proteins impair brain development and synaptic function in animal models and underlie genetic diseases in humans, such as encephalopathies, epilepsy, as well as neurodevelopmental, and degenerative disorders. This review presents the genetic and functional evidence linking v-ATPase subunits and accessory proteins to various brain disorders, from early-onset developmental epileptic encephalopathy to neurodegenerative diseases. We highlight the latest emerging therapeutic strategies aimed at mitigating lysosomal defects associated with v-ATPase dysfunction.

Tailoring biomaterials for vaccine delivery

Biomaterials are substances that can be injected, implanted, or applied to the surface of tissues in biomedical applications and have the ability to interact with biological systems to initiate therapeutic responses. Biomaterial-based vaccine delivery systems possess robust packaging capabilities, enabling sustained and localized drug release at the target site. Throughout the vaccine delivery process, they can contribute to protecting, stabilizing, and guiding the immunogen while also serving as adjuvants to enhance vaccine efficacy. In this article, we provide a comprehensive review of the contributions of biomaterials to the advancement of vaccine development. We begin by categorizing biomaterial types and properties, detailing their reprocessing strategies, and exploring several common delivery systems, such as polymeric nanoparticles, lipid nanoparticles, hydrogels, and microneedles. Additionally, we investigated how the physicochemical properties and delivery routes of biomaterials influence immune responses. Notably, we delve into the design considerations of biomaterials as vaccine adjuvants, showcasing their application in vaccine development for cancer, acquired immunodeficiency syndrome, influenza, corona virus disease 2019 (COVID-19), tuberculosis, malaria, and hepatitis B. Throughout this review, we highlight successful instances where biomaterials have enhanced vaccine efficacy and discuss the limitations and future directions of biomaterials in vaccine delivery and immunotherapy. This review aims to offer researchers a comprehensive understanding of the application of biomaterials in vaccine development and stimulate further progress in related fields.

Aurothioglucose encapsulated nanoparticles fostered neuroprotection in streptozotocin-induced Alzheimer's disease

Alzherimer's disease (AD) is an age-dependent ubiquitous ailment worldwide with limited therapies that only alleviate the symptoms of AD but do not cure them entirely because of the restricted blood-brain barrier passage of the drug. Hence with new advanced technology, nanoparticles can offer an opportunity as the active candidate to overcome the above limitations. Aurothioglucose, a synthetic glucose derivative of the gold compound, has been clinically proven to be an effective anti-inflammatory drug for rheumatic arthritis. Recently, several scientific groups have developed gold nanoparticle preparations and tested them for the treatment of dementia. This study was planned to prepare the PLGA nanoparticles of aurothioglucose (ATG) and check the neuroprotective potential against STZ-induced AD in rats. The nanoparticles were prepared using the double emulsion solvent evaporation method and characterized for various parameters such as drug-excipient interaction, particle size, zeta potential, and morphology. Then, rats were injected STZ (3 mg/kg/i.c.v., days 1 and 3) and ATG (5 and 10 mg/kg/s.c.), ATG NPs (2.5 and 5 mg/kg/s.c.) and donepezil (2 mg/kg/p.o) from 15th to 29th day. Behavior parameters were performed using an actophotometer, MWM, and ORT. On the 30th day, all the animals were sacrificed, and the brains were isolated for estimating biochemical, neurochemical, and proinflammatory markers. It was observed that ATG NPs significantly restored all behavior and neurotransmitter alterations caused by STZ. Also, it increased antioxidant levels and decreased inflammatory cytokines significantly, then ATG alone. Thus, the study suggests that ATG loaded PLGA NPs could be used as a novel therapeutic strategy to slow the process of AD.

Comprehensive Overview of Alzheimer's Disease: Etiological Insights and Degradation Strategies

Alzheimer's disease (AD) is the most prevalent neurodegenerative disorder and affects millions of individuals globally. AD is associated with cognitive decline and memory loss that worsens with aging. A statistical report using U.S. data on AD estimates that approximately 6.9 million individuals suffer from AD, a number projected to surge to 13.8 million by 2060. Thus, there is a critical imperative to pinpoint and address AD and its hallmark tau protein aggregation early to prevent and manage its debilitating effects. Amyloid-β and tau proteins are primarily associated with the formation of plaques and neurofibril tangles in the brain. Current research efforts focus on degrading amyloid-β and tau or inhibiting their synthesis, particularly targeting APP processing and tau hyperphosphorylation, aiming to develop effective clinical interventions. However, navigating this intricate landscape requires ongoing studies and clinical trials to develop treatments that truly make a difference. Genome-wide association studies (GWASs) across various cohorts identified 40 loci and over 300 genes associated with AD. Despite this wealth of genetic data, much remains to be understood about the functions of these genes and their role in the disease process, prompting continued investigation. By delving deeper into these genetic associations, novel targets such as kinases, proteases, cytokines, and degradation pathways, offer new directions for drug discovery and therapeutic intervention in AD. This review delves into the intricate biological pathways disrupted in AD and identifies how genetic variations within these pathways could serve as potential targets for drug discovery and treatment strategies. Through a comprehensive understanding of the molecular underpinnings of AD, researchers aim to pave the way for more effective therapies that can alleviate the burden of this devastating disease.

Polymeric Microneedles Enhance Transdermal Delivery of Therapeutics

This research presents the efficacy of polymeric microneedles in improving the transdermal permeation of methotrexate across human skin. These microneedles were fabricated from PLGA Expansorb® 50-2A and 50-8A and subjected to comprehensive characterization via scanning electron microscopy, Fourier-transform infrared spectroscopy, and mechanical analysis. We developed and assessed a methotrexate hydrogel for physicochemical and rheological properties. Dye binding, histological examinations, and assessments of skin integrity demonstrated the effective microporation of the skin by PLGA microneedles. We measured the dimensions of microchannels in the skin using scanning electron microscopy, pore uniformity analysis, and confocal microscopy. The skin permeation and disposition of methotrexate were researched in vitro. PLGA 50-8A microneedles appeared significantly longer, sharper, and more mechanically uniform than PLGA 50-2A needles. PLGA 50-8A needles generated substantially more microchannels, as well as deeper, larger, and more uniform channels in the skin than PLGA 50-2A needles. Microneedle insertion substantially reduced skin electrical resistance, accompanied by an elevation in transepidermal water loss values. PLGA 50-8A microneedle treatment provided a significantly higher cumulative delivery, flux, diffusion coefficient, permeability coefficient, and predicted steady-state plasma concentration; however, there was a shorter lag time than for PLGA 50-2A needles, base-treated, and untreated groups (p < 0.05). Conclusively, skin microporation using polymeric microneedles significantly improved the transdermal delivery of methotrexate.

Biomaterial strategies for regulating the neuroinflammatory response

Injury and disease in the central nervous system (CNS) can result in a dysregulated inflammatory environment that inhibits the repair of functional tissue. Biomaterials present a promising approach to tackle this complex inhibitory environment and modulate the mechanisms involved in neuroinflammation to halt the progression of secondary injury and promote the repair of functional tissue. In this review, we will cover recent advances in biomaterial strategies, including nanoparticles, hydrogels, implantable scaffolds, and neural probe coatings, that have been used to modulate the innate immune response to injury and disease within the CNS. The stages of inflammation following CNS injury and the main inflammatory contributors involved in common neurodegenerative diseases will be discussed, as understanding the inflammatory response to injury and disease is critical for identifying therapeutic targets and designing effective biomaterial-based treatment strategies. Biomaterials and novel composites will then be discussed with an emphasis on strategies that deliver immunomodulatory agents or utilize cell-material interactions to modulate inflammation and promote functional tissue repair. We will explore the application of these biomaterial-based strategies in the context of nanoparticle- and hydrogel-mediated delivery of small molecule drugs and therapeutic proteins to inflamed nervous tissue, implantation of hydrogels and scaffolds to modulate immune cell behavior and guide axon elongation, and neural probe coatings to mitigate glial scarring and enhance signaling at the tissue-device interface. Finally, we will present a future outlook on the growing role of biomaterial-based strategies for immunomodulation in regenerative medicine and neuroengineering applications in the CNS.

Blood-Brain Barrier-Targeting Nanoparticles: Biomaterial Properties and Biomedical Applications in Translational Neuroscience

Overcoming the blood-brain barrier (BBB) remains a significant hurdle in effective drug delivery to the brain. While the BBB serves as a crucial protective barrier, it poses challenges in delivering therapeutic agents to their intended targets within the brain parenchyma. To enhance drug delivery for the treatment of neurological diseases, several delivery technologies to circumvent the BBB have been developed in the last few years. Among them, nanoparticles (NPs) are one of the most versatile and promising tools. Here, we summarize the characteristics of NPs that facilitate BBB penetration, including their size, shape, chemical composition, surface charge, and importantly, their conjugation with various biological or synthetic molecules such as glucose, transferrin, insulin, polyethylene glycol, peptides, and aptamers. Additionally, we discuss the coating of NPs with surfactants. A comprehensive overview of the common in vitro and in vivo models of the BBB for NP penetration studies is also provided. The discussion extends to discussing BBB impairment under pathological conditions and leveraging BBB alterations under pathological conditions to enhance drug delivery. Emphasizing the need for future studies to uncover the inherent therapeutic properties of NPs, the review advocates for their role beyond delivery systems and calls for efforts translating NPs to the clinic as therapeutics. Overall, NPs stand out as a highly promising therapeutic strategy for precise BBB targeting and drug delivery in neurological disorders.

Progress in cardiac tissue engineering and regeneration: Implications of gelatin-based hybrid scaffolds

Cardiovascular diseases, particularly myocardial infarction (MI), remain a leading cause of morbidity and mortality worldwide. Current treatments for MI, more palliative than curative, have limitations in reversing the disease completely. Tissue engineering (TE) has emerged as a promising strategy to address this challenge and may lead to improved therapeutic approaches for MI. Gelatin-based scaffolds, including gelatin and its derivative, gelatin methacrylate (GelMA), have attracted significant attention in cardiac tissue engineering (CTE) due to their optimal physical and biochemical properties and capacity to mimic the native extracellular matrix (ECM). CTE mainly recruits two classes of gelatin/GelMA-based scaffolds: hydrogels and nanofibrous. This article reviews state-of-the-art gelatin/GelMA-based hybrid scaffolds currently applied for CTE and regenerative therapy. Hybrid scaffolds, fabricated by combining gelatin/GelMA hydrogel or nanofibrous scaffolds with other materials such as natural/synthetic polymers, nanoparticles, protein-based biomaterials, etc., are explored for enhanced cardiac tissue regeneration functionality. The engraftment of stem/cardiac cells, bioactive molecules, or drugs into these hybrid systems shows great promise in cardiac tissue repair and regeneration. Finally, the role of gelatin/GelMA scaffolds combined with the 3D bioprinting strategy in CTE will also be briefly highlighted.

Current non-invasive strategies for brain drug delivery: overcoming blood-brain barrier transport

BACKGROUND

The blood-brain barrier (BBB) is a complex and dynamic structure that serves as a gatekeeper, restricting the migrations of most compounds and molecules from blood into the central nervous system (CNS). The BBB plays a crucial role in maintaining CNS physiological function and brain homeostasis. It can protect the CNS from the entrance of toxic and infectious agents, however, it also restricts the drug permeation into brain to play a therapeutic role. The BBB has been the biggest limiting hurdle to medications entering the brain excluding from the brain about 100% of large-molecule and more than 98% of all small-molecule neurotherapeutics. As a result, it is of inability for drug molecule to reach requisite concentrations within the brain.

OBJECTIVE

With the aim of enhancing drug permeability and efficacy, a variety of strategies have been developed: invasive approaches, such as intraarterial delivery, intrathecal delivery, or administrating directly the drug intraventricularly and intracerebrally; non-invasive approaches that take advantage of innate BBB functions, using prodrugs, focused ultrasound, intranasal administration or nanotechnology.

CONCLUSIONS

Here we mainly review recent developments and challenges related to non-invasive BBB-crossing techniques, whose benefits include higher efficacy, easier application, less treatment burden, better patient acceptability, and adherence. Additionally, we also analyze the potential of non-invasive methods in the treatment of CNS disorders and render them as a most suitable platform for the management of neurological diseases.

Recent progress in PLGA-based microneedle-mediated transdermal drug and vaccine delivery

Microneedles (MNs) have recently been found to have applications in drug, vitamin, protein and vaccine delivery. Polymeric MN arrays continue to attract increasing attention due to their capability to bypass the skin's stratum corneum (SC) barrier with minimal invasiveness. These carriers can achieve the targeted intradermal delivery of drugs and vaccines and improve their transdermal delivery level. As a nontoxic FDA-approved copolymer, polylactic glycolic acid (PLGA) has good biocompatibility and biodegradability. Currently, PLGA-based MNs have a noticeable tendency to be utilized as a delivery system. This study focuses on the most recent advances in PLGA-based MNs. Both PLGA nanoparticle-based MNs and PLGA matrix-based MNs, created for the delivery of vaccines, drugs, proteins and other therapeutic agents, are discussed. The paper also discusses the various types of MNs and their potential applications. Finally, the prospects and challenges of PLGA-based MNs are reviewed.

Counteracting Immunosenescence-Which Therapeutic Strategies Are Promising?

Aging attenuates the overall responsiveness of the immune system to eradicate pathogens. The increased production of pro-inflammatory cytokines by innate immune cells under basal conditions, termed inflammaging, contributes to impaired innate immune responsiveness towards pathogen-mediated stimulation and limits antigen-presenting activity. Adaptive immune responses are attenuated as well due to lowered numbers of naïve lymphocytes and their impaired responsiveness towards antigen-specific stimulation. Additionally, the numbers of immunoregulatory cell types, comprising regulatory T cells and myeloid-derived suppressor cells, that inhibit the activity of innate and adaptive immune cells are elevated. This review aims to summarize our knowledge on the cellular and molecular causes of immunosenescence while also taking into account senescence effects that constitute immune evasion mechanisms in the case of chronic viral infections and cancer. For tumor therapy numerous nanoformulated drugs have been developed to overcome poor solubility of compounds and to enable cell-directed delivery in order to restore immune functions, e.g., by addressing dysregulated signaling pathways. Further, nanovaccines which efficiently address antigen-presenting cells to mount sustained anti-tumor immune responses have been clinically evaluated. Further, senolytics that selectively deplete senescent cells are being tested in a number of clinical trials. Here we discuss the potential use of such drugs to improve anti-aging therapy.

A nano-delivery system based on preventing degradation and promoting absorption to improve the oral bioavailability of insulin

Oral insulin delivery can improve patient compliance and simulate the portal-peripheral insulin concentration gradient produced by endogenous insulin, so oral insulin delivery has a broad prospect. However, some characteristics of the gastrointestinal tract, lead to low oral bioavailability. Therefore, a "ternary mutual-assist" nano-delivery system based on poly(lactide-co-glycolide) (PLGA) as the backbone combined with ionic liquids (IL) and vitamin B12-chitosan (VB12-CS) was constructed in this study, the protein protection performance of IL improves the room temperature stability of the loaded insulin during nanocarrier preparation, transportation and storage to a certain extent, and the protein protection function of IL combined with the slow degradation property of PLGA and the pH-responsive function of VB12-CS to prevent the degradation of insulin in the gastrointestinal tract. In addition, the mucosal adhesion function of VB12-CS, VB12 receptor- and clathrin-mediated transcellular transport involving VB12-CS and IL, and paracellular transport mediated by IL and CS can be combined to improve the intestinal epithelial transport efficiency of insulin, thus, the nanocarrier has stronger preventing degradation and promoting absorption effects. Pharmacodynamic studies showed that after oral administration of VB12-CS-PLGA@IL@INS NPs to diabetic mice, the blood glucose level decreased to about 13 mmol/L, below the critical point of 16.7 mmol/L, and the blood glucose reached a normal level, which was 0.4 times of the blood glucose value before administration, its relative pharmacological bioavailability was 31.8 %, higher than the general nanocarriers (10-20 %) and more beneficial to the clinical transformation of oral insulin.

Defective lysosomal acidification: a new prognostic marker and therapeutic target for neurodegenerative diseases

Lysosomal acidification dysfunction has been implicated as a key driving factor in the pathogenesis of neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease. Multiple genetic factors have been linked to lysosomal de-acidification through impairing the vacuolar-type ATPase and ion channels on the organelle membrane. Similar lysosomal abnormalities are also present in sporadic forms of neurodegeneration, although the underlying pathogenic mechanisms are unclear and remain to be investigated. Importantly, recent studies have revealed early occurrence of lysosomal acidification impairment before the onset of neurodegeneration and late-stage pathology. However, there is a lack of methods for organelle pH monitoring in vivo and a dearth of lysosome-acidifying therapeutic agents. Here, we summarize and present evidence for the notion of defective lysosomal acidification as an early indicator of neurodegeneration and urge the critical need for technological advancement in developing tools for lysosomal pH monitoring and detection both in vivo and for clinical applications. We further discuss current preclinical pharmacological agents that modulate lysosomal acidification, including small molecules and nanomedicine, and their potential clinical translation into lysosome-targeting therapies. Both timely detection of lysosomal dysfunction and development of therapeutics that restore lysosomal function represent paradigm shifts in targeting neurodegenerative diseases.

Modulating Lysosomal pH through Innovative Multimerized Succinic Acid-Based Nucleolipid Derivatives

The multimerization of active compounds has emerged as a successful approach, mainly to address the multivalency of numerous biological targets. Regarding the pharmaceutical prospect, carrying several active ingredient units on the same synthetic scaffold was a practical approach to enhance drug delivery or biological activity with a lower global concentration. Various examples have highlighted better in vivo stability and therapeutic efficiency through sustained action over monomeric molecules. The synthesis strategy aims to covalently connect biologically active monomers to a central core using simple and efficient reaction steps. Despite extensive studies reporting carbohydrate or even peptide multimerization developed for therapeutic activities, very few are concerned with nucleic acid derivatives. In the context of our efforts to build non-viral nucleolipid (NL)-based nanocarriers to restore lysosomal acidification defects, we report here a straightforward synthesis of tetrameric NLs, designed as prodrugs that are able to release no more than one but four biocompatible succinic acid units. The use of oil-in-water nanoemulsion-type vehicles allowed the development of lipid nanosystems crossing the membranes of human neuroblastoma cells. Biological evaluations have proved the effective release of the acid within the lysosome of a genetic and cellular model of Parkinson's disease through the recovery of an optimal lysosomal pH associated with a remarkably fourfold lower concentration of active ingredients than with the corresponding monomers. Overall, these results suggest the feasibility, the therapeutic opportunity, and the better tolerance of multimeric compounds compared to only monomer molecules.

Polylactic-co-glycolic acid-based nanoparticles modified with peptides and other linkers cross the blood-brain barrier for targeted drug delivery

Because of the blood-brain barrier, only a limited fraction of drugs can penetrate the brain. As a result, there is a need to take larger doses of the drug, which may result in numerous undesirable side effects. Over the past few decades, a plethora of research has been conducted to address this issue. In recent years, the field of nanomedicine research has reported promising findings. Currently, numerous types of polylactic-co-glycolic acid-based drug-delivery systems are being studied, and great progress has been made in the modification of their surfaces with a variety of ligands. In this review, the authors highlight the preparation of polylactic-co-glycolic acid-based nanoparticles and single- and dual-targeted peptide modifications for site-specific drug delivery into the brain.

Pathogenic Aspects and Therapeutic Avenues of Autophagy in Parkinson's Disease

The progressive aging of the population and the fact that Parkinson's disease currently does not have any curative treatment turn out to be essential issues in the following years, where research has to play a critical role in developing therapy. Understanding this neurodegenerative disorder keeps advancing, proving the discovery of new pathogenesis-related genes through genome-wide association analysis. Furthermore, the understanding of its close link with the disruption of autophagy mechanisms in the last few years permits the elaboration of new animal models mimicking, through multiple pathways, different aspects of autophagic dysregulation, with the presence of pathological hallmarks, in brain regions affected by Parkinson's disease. The synergic advances in these fields permit the elaboration of multiple therapeutic strategies for restoring autophagy activity. This review discusses the features of Parkinson's disease, the autophagy mechanisms and their involvement in pathogenesis, and the current methods to correct this cellular pathway, from the development of animal models to the potentially curative treatments in the preclinical and clinical phase studies, which are the hope for patients who do not currently have any curative treatment.

Stem Cell-derived Extracellular Vesicles: A Promising Nano Delivery Platform to the Brain?

A very important cause of the frustration with drug therapy for central nervous system (CNS) diseases is the failure of drug delivery. The blood-brain barrier (BBB) prevents most therapeutic molecules from entering the brain while maintaining CNS homeostasis. Scientists are keen to develop new brain drug delivery systems to solve this dilemma. Extracellular vesicles (EVs), as a class of naturally derived nanoscale vesicles, have been extensively studied in drug delivery due to their superior properties. This review will briefly present current brain drug delivery strategies, including invasive and non-invasive techniques that target the brain, and the application of nanocarriers developed for brain drug delivery in recent years, especially EVs. The cellular origin of EVs affects the surface protein, size, yield, luminal composition, and other properties of EVs, which are also crucial in determining whether EVs are useful as drug carriers. Stem cell-derived EVs, which inherit the properties of parental cells and avoid the drawbacks of cell therapy, have always been favored by researchers. Thus, in this review, we will focus on the application of stem cell-derived EVs for drug delivery in the CNS. Various nucleic acids, proteins, and small-molecule drugs are loaded into EVs with or without modification and undergo targeted delivery to the brain to achieve their therapeutic effects. In addition, the challenges facing the clinical application of EVs as drug carriers will also be discussed. The directions of future efforts may be to improve drug loading efficiency and precise targeting.

Understanding the Therapeutic Approaches for Neuroprotection

The term "neurodegenerative disorders" refers to a group of illnesses in which deterioration of nerve structure and function is a prominent feature. Cognitive capacities such as memory and decision-making deteriorate as a result of neuronal damage. The primary difficulty that remains is safeguarding neurons since they do not proliferate or regenerate spontaneously and are therefore not substituted by the body after they have been damaged. Millions of individuals throughout the world suffer from neurodegenerative diseases. Various pathways lead to neurodegeneration, including endoplasmic reticulum stress, calcium ion overload, mitochondrial dysfunction, reactive oxygen species generation, and apoptosis. Although different treatments and therapies are available for neuroprotection after a brain injury or damage, the obstacles are inextricably connected. Several studies have revealed the pathogenic effects of hypothermia, different breathed gases, stem cell treatments, mitochondrial transplantation, multi-pharmacological therapy, and other therapies that have improved neurological recovery and survival outcomes after brain damage. The present review highlights the use of therapeutic approaches that can be targeted to develop and understand significant therapies for treating neurodegenerative diseases.

Progress in oral insulin delivery by PLGA nanoparticles for the management of diabetes

Currently, the only practical way to treat type 1 and advanced insulin-dependent type 2 diabetes mellitus (T1/2DM) is the frequent subcutaneous injection of insulin, which is significantly different physiologically from endogenous insulin secretion from pancreatic islets and can lead to hyperinsulinemia, pain, and infection in patients with poor compliance. Hence, oral insulin delivery has been actively pursued to revolutionize the treatment of insulin-dependent diabetes. In this review, we provide an overview of recent progress in developing poly(lactic co-glycolic acid) (PLGA) nanoparticles (NPs) for oral insulin delivery. Different strategies for insulin-loaded PLGA NPs to achieve normoglycemic effects are discussed. Finally, challenges and future perspectives of PLGA NPs for oral insulin delivery are put forward.

Recent progress in the intranasal PLGA-based drug delivery for neurodegenerative diseases treatment

One of the most challenging problems of the current treatments of neurodegenerative diseases is related to the permeation and access of most therapeutic agents to the central nervous system (CNS), prevented by the blood-brain barrier (BBB). Recently, intranasal (IN) delivery has opened new prospects because it directly delivers drugs for neurological diseases into the brain via the olfactory route. Recently, PLGA-based nanocarriers have attracted a lot of interest for IN delivery of drugs. This review gathered clear and concise statements of the recent progress of the various developed PLGA-based nanocarriers for IN drug delivery in brain diseases including Alzheimer's, Parkinson's, brain tumors, ischemia, epilepsy, depression, and schizophrenia. Subsequently, future perspectives and challenges of PLGA-based IN administration are discussed briefly.

Multi-target tyrosine kinase inhibitor nanoparticle delivery systems for cancer therapy

Multi-target Tyrosine Kinase Inhibitors (MTKIs) have drawn substantial attention in tumor therapy. MTKIs could inhibit tumor cell proliferation and induce apoptosis by blocking the activity of tyrosine kinase. However, the toxicity and drug resistance of MTKIs severely restrict their further clinical application. The nano pharmaceutical technology based on MTKIs has attracted ever-increasing attention in recent years. Researchers deliver MTKIs through various types of nanocarriers to overcome drug resistance and improve considerably therapeutic efficiency. This review intends to summarize comprehensive applications of MTKIs nanoparticles in malignant tumor treatment. Firstly, the mechanism and toxicity were introduced. Secondly, various nanocarriers for MTKIs delivery were outlined. Thirdly, the combination treatment schemes and drug resistance reversal strategies were emphasized to improve the outcomes of cancer therapy. Finally, conclusions and perspectives were summarized to guide future research.

Potential nanocarrier-mediated miRNA-based therapy approaches for multiple sclerosis

Multiple sclerosis (MS) is an autoimmune neuroinflammatory disorder attributed to neurodegeneration and demyelination, resulting in neurological impairment. miRNA has a significant role in biological processes in MS. In this review, we focus on the feasibility of delivering miRNAs through nanoformulations for managing MS. We provide a brief discussion of miRNA synthesis and evidence for miRNA dysregulation in MS. We also highlight formulation strategies and resulting technologies for the effective delivery of miRNAs through nanocarrier systems for achieving high therapeutic benefits.

Native PLGA nanoparticles regulate APP metabolism and protect neurons against β-amyloid toxicity: Potential significance in Alzheimer's disease pathology

Biodegradable poly(lactic-co-glycolic acid)(PLGA) nanoparticles have been used extensively in delivering drugs to target tissues due to their excellent biocompatibility. Evidence suggests that PLGA-conjugated drugs/agents can attenuate pathology in cellular/animal models of Alzheimer's disease (AD), which is initiated by increased level/aggregation of amyloid β (Aβ) peptide generated from amyloid precursor protein (APP). The beneficial effects were attributed to conjugated-drugs rather than to PLGA nanoparticles. Interestingly, we recently reported that PLGA without any drug/agent (native PLGA) can suppress Aβ aggregation/toxicity. However, very little is known about the internalization, subcellular localization or effects of PLGA in neurons. In this study, using primary mouse cortical neurons, we first showed that native PLGA is internalized by an energy-mediated clathrin-dependent/-independent pathway and is localized in endosomal-lysosomal-autophagic vesicles. By attenuating internalization, PLGA can protect neurons against Aβ-mediated toxicity. Additionally, PLGA treatment altered expression profiles of certain AD-associated genes and decreased the levels of APP, its cleaved products α-/β-CTFs and Aβ peptides in mouse as well as iPSC-derived neurons from control and AD patients. Collectively, these results suggest that native PLGA not only protects neurons against Aβ-induced toxicity but also influences the expression of AD-related genes/proteins - highlighting PLGA's implication in normal and AD-related pathology.

Targeting Macroautophagy as a Therapeutic Opportunity to Treat Parkinson's Disease

Macroautophagy, an evolutionary conserved catabolic process in the eukaryotic cell, regulates cellular homeostasis and plays a decisive role in self-engulfing proteins, protein aggregates, dysfunctional or damaged organelles, and invading pathogens. Growing evidence from in vivo and in vitro models shows that autophagy dysfunction plays decisive role in the pathogenesis of various neurodegenerative diseases, including Parkinson's disease (PD). PD is an incurable and second most common neurodegenerative disease characterised by neurological and motor dysfunction accompanied of non-motor symptoms that can also reduce the life quality of patients. Despite the investment in research, the aetiology of the disease is still unknown and the therapies available are aimed mostly at ameliorating motor symptoms. Hence, therapeutics regulating the autophagy pathway might play an important role controlling the disease progression, reducing neuronal loss and even ameliorating non-motor symptoms. In this review, we highlight potential therapeutic opportunities involved in different targeting options like an initiation of autophagy, Leucine-rich repeat kinase 2 (LRRK2) inhibition, mitophagy, lysosomes, lipid metabolism, immune system, gene expression, biomarkers, and also non-pharmacological interventions. Thus, strategies to identify therapeutics targeting the pathways modulating autophagy might hold a future for therapy development against PD.

Applications of Various Types of Nanomaterials for the Treatment of Neurological Disorders

Neurological disorders (NDs) are recognized as one of the major health concerns globally. According to the World Health Organization (WHO), neurological disorders are one of the main causes of mortality worldwide. Neurological disorders include Alzheimer’s disease, Parkinson′s disease, Huntington′s disease, Amyotrophic lateral sclerosis, Frontotemporal dementia, Prion disease, Brain tumor, Spinal cord injury, and Stroke. These diseases are considered incurable diseases because no specific therapies are available to cross the blood-brain barrier (BBB) and reach the brain in a significant amount for the pharmacological effect in the brain. There is a need for the development of strategies that can improve the efficacy of drugs and circumvent BBB. One of the promising approaches is the use of different types of nano-scale materials. These nano-based drugs have the ability to increase the therapeutic effect, reduce toxicity, exhibit good stability, targeted delivery, and drug loading capacity. Different types and shapes of nanomaterials have been widely used for the treatment of neurological disorders, including quantum dots, dendrimers, metallic nanoparticles, polymeric nanoparticles, carbon nanotubes, liposomes, and micelles. These nanoparticles have unique characteristics, including sensitivity, selectivity, and the ability to cross the BBB when used in nano-sized particles, and are widely used for imaging studies and treatment of NDs. In this review, we briefly summarized the recent literature on the use of various nanomaterials and their mechanism of action for the treatment of various types of neurological disorders.

PLGA-Based Nanoplatforms in Drug Delivery for Inhibition and Destruction of Microbial Biofilm

The biofilm community of microorganisms has been identified as the dominant mode of microbial growth in nature and a common characteristic of different microorganisms such as Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis. The biofilm structure helps in the protection from environmental threats including host immune system and antimicrobial agents. Thus, the biofilm community has led to a higher prevalence of multidrug-resistant (MDR) strains in recent years. In this regard, the use of a new class of antibiotics, natural compounds, and anti-biofilm enzymes has been considered for the destruction of the microbial biofilm. However, different drawbacks such as low penetration, high susceptibility to degradation, instability, and poor solubility in aqueous solutions limit the use of anti-biofilm agents (ABAs) in a clinical setting. As such, recent studies have been using poly lactic-co-glycolic acid (PLGA)-based nanoplatforms (PLGA NPFs) for delivery of ABAs that have reported promising results. These particles, due to proper drug loading and release kinetics, could suppress microbial attachment, colonization, and biofilm formation for a long time. Additionally, PLGA NPFs, because of the high drug-loading efficiencies, hydrophilic surface, negative charge, and electrostatic interaction, lead to effective penetration of antibiotics to the deeper layer of the biofilm, thereby eliminating the microbial biofilm. Thus, PLGA NPFs could be considered as a potential candidate for coating catheters and other medical material surfaces for inhibition and destruction of the microbial biofilm. However, the exact interaction of PLGA NPFs and the microbial biofilm should be evaluated in animal studies. Additionally, a future goal will be to develop PLGA formulations as systems that can be used for the treatment of the MDR microbial biofilm, since the exact interactions of PLGA NPFs and these biofilm structures are not elucidated. In the present review article, we have discussed various aspects of PLGA usage for inhibition and destruction of the microbial biofilm along with different methods and procedures that have been used for improving PLGA NPF efficacy against the microbial biofilm.

Potential Antiviral Strategy Exploiting Dependence of SARS-CoV-2 Replication on Lysosome-Based Pathway

The recent novel coronavirus (SARS-CoV-2) disease (COVID-19) outbreak created a severe public health burden worldwide. Unfortunately, the SARS-CoV-2 variant is still spreading at an unprecedented speed in many countries and regions. There is still a lack of effective treatment for moderate and severe COVID-19 patients, due to a lack of understanding of the SARS-CoV-2 life cycle. Lysosomes, which act as “garbage disposals” for nearly all types of eukaryotic cells, were shown in numerous studies to support SARS-CoV-2 replication. Lysosome-associated pathways are required for virus entry and exit during replication. In this review, we summarize experimental evidence demonstrating a correlation between lysosomal function and SARS-CoV-2 replication, and the development of lysosomal perturbation drugs as anti-SARS-CoV-2 agents.

Polydatin Improves Sepsis-Associated Encephalopathy by Activating Sirt1 and Reducing p38 Phosphorylation

INTRODUCTION

Our previous study confirmed that polydatin (PD) can alleviate sepsis-induced multiorgan dysfunction (in the vascular endothelium, kidney, and small intestine) by activating Sirt1 and that PD protects against traumatic brain injury in rats via increased Sirt1 and inhibition of the p38-mediated mitogen-activated protein kinase (MAPK) pathway. We aim to investigate whether PD may also attenuate sepsis-associated encephalopathy (SAE).

METHODS

In this study, we constructed an SAE mouse model by cecal ligation and puncture (CLP) and measured Sirt1 protein activity, p38 phosphorylation, brain tissue pathological damage, pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6), mitochondrial function (mitochondrial membrane potential, ATP content, and reactive oxygen species), neurological function, and animal survival time. Sirt1 selective inhibitor Ex527 and p38 inhibitor SB203580 were used to explore the possible mechanism of PD in SAE.

RESULTS

We confirmed that PD inhibits neuroinflammation evidenced by reduced proinflammatory cytokines. In addition, PD protects mitochondria as demonstrated by restored mitochondrial membrane potential and adenosine triphosphate (ATP) content, and decreased reactive oxygen species (ROS) level. As we expected, p38 inhibition reduces neuroinflammation and mitochondrial damage. In contrast, Sirt1 inhibition aggravates cerebral cortex mitochondrial damage and neuroinflammation and promotes phosphorylation of p38. Mechanistically, PD treatment suppressed p38 phosphorylation and consequently reduced the neuroinflammatory response, and these effects were blocked by the Sirt selective inhibitor Ex527.

CONCLUSIONS

This study, to the best of our knowledge, is the first to demonstrate that PD alleviates SAE, at least partially, by upregulating Sir1-mediated neuroinflammation inhibition and mitochondrial function protection.

Trehalose-Based Nucleolipids as Nanocarriers for Autophagy Modulation: An In Vitro Study

The Autophagy Lysosomal Pathway is one of the most important mechanisms for removing dysfunctional cellular components. Increasing evidence suggests that alterations in this pathway play a pathogenic role in Parkinson's disease, making it a point of particular vulnerability. Numerous studies have proposed nanotechnologies as a promising approach for delivering active substances within the central nervous system to treat and diagnose neurodegenerative diseases. In this context, the aim was to propose the development of a new pharmaceutical technology for the treatment of neurodegenerative diseases. We designed a trehalose-based nanosystem by combining both a small natural autophagy enhancer molecule named trehalose and an amphiphilic nucleolipid conjugate. To improve nucleolipid protection and cellular uptake, these conjugates were formulated by rapid mixing in either solid lipid nanoparticles (Ø = 120.4 ± 1.4 nm) or incorporated into poly(lactic-co-glycolic acid) nanoparticles (Ø = 167.2 ± 2.4 nm). In vitro biological assays demonstrated a safe and an efficient cellular uptake associated with autophagy induction. Overall, these nucleolipid-based formulations represent a promising new pharmaceutical tool to deliver trehalose and restore the autophagy impaired function.

Acidic nanoparticles protect against α-synuclein-induced neurodegeneration through the restoration of lysosomal function

Parkinson's disease (PD) is an age‐related neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra, associated with the accumulation of misfolded α‐synuclein and lysosomal impairment, two events deemed interconnected. Protein aggregation is linked to defects in degradation systems such as the autophagy‐lysosomal pathway, while lysosomal dysfunction is partly related to compromised acidification. We have recently proven that acidic nanoparticles (aNPs) can re‐acidify lysosomes and ameliorate neurotoxin‐mediated dopaminergic neurodegeneration in mice. However, no lysosome‐targeted approach has yet been tested in synucleinopathy models in vivo. Here, we show that aNPs increase α‐synuclein degradation through enhancing lysosomal activity in vitro. We further demonstrate in vivo that aNPs protect nigral dopaminergic neurons from cell death, ameliorate α‐synuclein pathology, and restore lysosomal function in mice injected with PD patient‐derived Lewy body extracts carrying toxic α‐synuclein aggregates. Our results support lysosomal re‐acidification as a disease‐modifying strategy for the treatment of PD and other age‐related proteinopathies.

HexA-Enzyme Coated Polymer Nanoparticles for the Development of a Drug-Delivery System in the Treatment of Sandhoff Lysosomal Storage Disease

Lysosomal storage disorders (LSDs) are a set of metabolic diseases caused by mutations in genes that are in charge of the production of lysosomal enzymes, resulting in the buildup of non-degraded substrates and the consequent systemic damage that mainly involves the Central Nervous System (CNS). One of the most widely used and studied treatments is Enzyme Replacement Therapy, which is based on the administration of the recombinant deficient enzyme. This strategy has often proved fallacious due to the enzyme instability in body fluids and its inability to reach adequate levels in the CNS. In this work, we developed a system based on nanotechnology that allows a stable enzyme to be obtained by its covalent immobilization on nanoparticles (NPs) of polylactic acid, subsequently administered to a cellular model of LSDs, i.e., Sandhoff disease, caused by the absence or deficiency of the β-d-N-acetyl-hexosaminidase A (HexA) enzyme. The HexA enzymes, loaded onto the polymeric NPs through an immobilization procedure that has already been investigated and validated, were found to be stable over time, maintain optimal kinetic parameters, be able to permeate the plasma membrane, hydrolyze HexA’s natural substrate, and restore enzyme activity close to the levels of healthy cells. These results thus lay the foundation for testing the HexA-NPs in animal models of the disease and thus obtaining an efficient drug-delivery system.