2-(2-Cholesteroxyethoxyl)ethyl 3'-S-glutathionylpropionate and its self-assembled micelles for brain delivery: Design, synthesis and evaluation

Borneol-Modified Schisandrin B Micelles Cross the Blood-Brain Barrier To Treat Alzheimer's Disease in Aged Mice

Objective: Schisandrin B (Sch B) is a bioactive dibenzocyclooctadiene derizative that is prevalent in the fruit of Schisandra chinensis. Numerous studies have demonstrated that Sch B has a neuroprotective action by reducing oxidative stress and effectively preventing inflammation. It follows that Sch B is a potential treatment for Alzheimer's disease (AD). However, the drug's solubility, bioavailability, and lower permeability of the blood-brain barrier (BBB) can all reduce its efficacy during the therapy process. Therefore, this study constructed borneol-modified schisandrin B micelles (Bor-Sch B-Ms), which increase brain targeting by accurately delivering medications to the brain, effectively improving bioavailability. High therapeutic efficacy has been achieved at the pathological site. Methods: Bor-Sch B-Ms were prepared using the thin film dispersion approach in this article. On the one hand, to observe the targeting effect of borneol, we constructed a blood-brain barrier (BBB) model in vitro and studied the ability of micelles to cross the BBB. On the other hand, the distribution of micelle drugs and their related pharmacological effects on neuroinflammation, oxidative stress, and neuronal damage were studied through in vivo administration in mice. Results: In vitro studies have demonstrated that the drug uptake of bEnd.3 cells was increased by the borneol alteration on the surface of the nano micelles, implying that Bor-Sch B-Ms can promote the therapeutic effect of N2a cells. This could result in more medicines entering the BBB. In addition, in vivo studies revealed that the distribution and circulation time of medications in the brain tissue were significantly higher than those in other groups, making it more suitable for the treatment of central nervous system diseases. Conclusion: As a novel nanodrug delivery system, borneol modified schisandrin B micelles have promising research prospects in the treatment of Alzheimer's disease.

mTOR-Mediated Immunometabolic Reprogramming Nanomodulators Enable Sensitive Switching of Energy Deprivation-Induced Microglial Polarization for Alzheimer's Disease Management

Metabolic reprogramming that senses brain homeostasis imbalances is necessary to drive detrimental microglial polarization, and specific targeting of this process contributes to the flexible control of pathological inflammatory responses in Alzheimer's disease (AD), displaying distinctive therapeutic benefits. Herein, glutathione-functionalized gold nanocages loaded with the immunosuppressant fingolimod hydrochloride are developed as brain-targeted and microglia-located immunometabolic reprogramming nanomodulators (GAF NPs) for AD management. By virtue of glutathione-mediated transport properties, this nanomodulator can cross the blood-brain barrier and localize to microglia in AD lesions. Through blocking Akt/mTOR/HIF-1α signaling pathways, GAF NPs not only promote the dominated metabolic shift from glycolysis to oxidative phosphorylation under immune activation but also inhibit transporter-mediated glucose overconsumption by microglia. Correlation analysis based on real-time bioenergetic assessment and 18F-labeled fluorodeoxyglucose (FDG) PET reveals that brain glucose utilization and metabolism restored by GAF NP treatment can serve as a sensitive and effective indicator for microglial M1 to M2 polarization switching, ultimately alleviating neuroinflammation and its derived neurodegeneration as well as ameliorating cognitive decline in AD mice. This work highlights a potential nanomedicine aimed at modifying mTOR-mediated immunometabolic reprogramming to halt energy deprivation-induced AD progression.

Cell Membrane Biomimetic Nanoparticles with Potential in Treatment of Alzheimer's Disease

Alzheimer's disease (AD) is to blame for about 60% of dementia cases worldwide. The blood-brain barrier (BBB) prevents many medications for AD from having clinical therapeutic effects that can be used to treat the affected area. Many researchers have turned their attention to cell membrane biomimetic nanoparticles (NPs) to solve this situation. Among them, NPs can extend the half-life of drugs in the body as the "core" of the wrapped drug, and the cell membrane acts as the "shell" of the wrapped NPs to functionalize the NPs, which can further improve the delivery efficiency of nano-drug delivery systems. Researchers are learning that cell membrane biomimetic NPs can circumvent the BBB's restriction, prevent harm to the body's immune system, extend the period that NPs spend in circulation, and have good biocompatibility and cytotoxicity, which increases efficacy of drug release. This review summarized the detailed production process and features of core NPs and further introduced the extraction methods of cell membrane and fusion methods of cell membrane biomimetic NPs. In addition, the targeting peptides for modifying biomimetic NPs to target the BBB to demonstrate the broad prospects of cell membrane biomimetic NPs drug delivery systems were summarized.

New Drug Delivery Systems Developed for Brain Targeting

The blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (B_CSF) are two of the most complex and sophisticated concierges that defend the central nervous system (CNS) by numerous mechanisms. While they maintain the neuro-ecological homeostasis through the regulated entry of essential biomolecules, their conservative nature challenges the entry of most of the drugs intended for CNS delivery. Targeted delivery challenges for a diverse spectrum of therapeutic agents/drugs (non-small molecules, small molecules, gene-based therapeutics, protein and peptides, antibodies) are diverse and demand specialized delivery and disease-targeting strategies. This review aims to capture the trends that have shaped the current brain targeting research scenario. This review discusses the physiological, neuropharmacological, and etiological factors that participate in the transportation of various drug delivery cargoes across the BBB/B_CSF and influence their therapeutic intracranial concentrations. Recent research works spanning various invasive, minimally invasive, and non-invasive brain- targeting approaches are discussed. While the pre-clinical outcomes from many of these approaches seem promising, further research is warranted to overcome the translational glitches that prevent their clinical use. Non-invasive approaches like intranasal administration, P-glycoprotein (P-gp) inhibition, pro-drugs, and carrier/targeted nanocarrier-aided delivery systems (alone or often in combination) hold positive clinical prospects for brain targeting if explored further in the right direction.