Search Results (80)

The blood–brain barrier (BBB) restricts therapeutic delivery to the central nervous system (CNS), hindering the treatment of neurological disorders, such as Alzheimer’s disease, Parkinson’s disease, brain cancers, and stroke. Aptamers, short single-stranded DNA or RNA oligonucleotides that can fold into unique 3D shapes and bind to specific target molecules, offer high affinity and specificity, low immunogenicity, and promising BBB penetration via receptor-mediated transcytosis targeting receptors such as the transferrin receptor (TfR) and low-density lipoprotein receptor-related protein 1 (LRP1). This review examines aptamer design through the Systematic Evolution of Ligands by Exponential Enrichment (SELEX) and its variants, mechanisms of BBB crossing, and applications in CNS disorders. Recent advances, including in silico optimization, in vivo SELEX, BBB chip-based MPS-SELEX, and nanoparticle–aptamer hybrids, have identified brain-penetrating aptamers and enhanced the brain delivery efficiency. This review highlights the potential of aptamers to transform CNS-targeted therapies. Full article

Background: Antibodies that cross the blood–brain barrier (BBB) by targeting receptor-mediated transport (RMT) systems can allow efficient drug delivery to the central nervous system (CNS). In order to improve brain uptake of antibodies, their binding properties have been engineered, but it is not always clear what antibody properties dictate BBB transport efficiency. In this study, we therefore developed and employed an in vitro phenotypic screen and a quantitative transcytosis assay in an attempt to identify improved variants of a previously identified BBB transcytosing antibody known as 46.1. Methods: First, a random mutagenic 46.1 antibody phage display library was screened for improved transcytosis through a human induced pluripotent stem cell (iPSC)-derived BBB model. These screens yielded antibody variants that enriched over multiple screening rounds; however, when produced as soluble antibodies, the variants did not display improved in vitro transcytosis over the wild-type (WT) 46.1 antibody. As a second strategy, we performed a targeted histidine point mutation of a solvent-exposed residue in each complementarity-determining region (CDR) and evaluated the in vitro transcytosis capacity of the variants. Results and Conclusions: In this way, we identified a 46.1 variant, R162H, with modestly improved in vitro transcytosis properties. These results show that the iPSC-derived BBB screening insights and evaluation strategies presented here could facilitate the engineering and optimization of lead antibodies for CNS delivery. Full article

Cardiovascular diseases remain the leading cause of death worldwide and are often managed through invasive surgical procedures such as heart transplantation, ventricular assist device implantation, coronary artery bypass grafting, and stent placement. However, significant unmet medical needs persist in this field. The development of pharmaceutical agents using non-invasive delivery strategies is therefore of critical importance. Current treatments often target peripheral tissues or organs—such as capillary endothelial cells, vascular smooth muscle, and renal tubules—to reduce cardiac workload by lowering blood pressure. However, effective drug delivery directly to the myocardium continues to pose a significant challenge. For conditions such as congestive heart failure (CHF) and myocardial infarction (MI), targeted delivery of therapeutic agents to the heart is essential. In this perspective review, I discuss the potential and emerging strategies for non-invasive cardiac drug delivery, focusing on receptor-mediated endocytosis and transcytosis using nanoparticle-based delivery systems that have frequently been employed for targeting the brain or cancer cells although their use for cardiac delivery remains largely unexplored. Full article

The plasma membrane (PM) of eukaryotic cells plays a key role in the response to stress, acting as the first line of defense against environmental changes and protecting cells against intracellular perturbations. In this work, we explore how membrane-bound chaperones and membrane lipid domains work together to shape plasma membrane properties—a partnership we refer to as the “epichaperome–plasma membrane lipid axis.” This axis influences membrane fluidity, curvature, and domain organization, which in turn shapes the spatial and temporal modulation of signaling platforms and pathways essential for maintaining cellular integrity and homeostasis. Changes in PM fluidity can modulate the activity of ion channels, such as transient receptor potential (TRP) channels. These changes also affect processes such as endocytosis and mechanical signal transduction. The PM proteome undergoes rapid changes in response to membrane perturbations. Among these changes, the expression of heat shock proteins (HSPs) and their accumulation at the PM are essential mediators in regulating the physical state and functional properties of the membrane. Because of the pivotal role in stress adaptation, HSPs influence a wide range of cellular processes, which we grouped into three main categories: (i) mechanistic insights, differentiating in vitro (liposome, reconstituted membrane systems) and in vivo evidence for HSP-PM recruitment; (ii) functional outputs, spanning how ion channels are affected, changes in membrane fluidity, transcytosis, and the process of endocytosis and exosome release; and (iii) pathological effects, focusing on how rewired lipid–chaperone crosstalk in cancer drives resistance to drugs through altered membrane composition and signaling. Finally, we highlight Membrane Lipid Therapy (MLT) strategies, such as nanocarriers targeting specific PM compartments or small molecules that inhibit HSP recruitment, as promising approaches to modulate the functional stability of epichaperome assembly and membrane functionality, with profound implications for tumorigenesis. Full article

Background/Objectives: Receptor-mediated transcytosis utilizing the native transporters at the blood–brain barrier (BBB) is a growing strategy for the delivery of therapeutics to the brain. One of the major challenges in identifying appropriate human transcytosis targets is that there is a species-specific transporter expression profile at the BBB, complicating translation of successful preclinical candidates into humans. In an effort to overcome this obstacle and identify proteins capable of binding human-relevant BBB ligands, we generated and screened a BBB-targeting library against human-induced pluripotent stem cell-derived brain microvascular endothelial-like cells (iPSC-derived BMEC-like cells). As targeting molecules, we used lamprey antibodies, known as variable lymphocyte receptors (VLRs), and generated a VLR library by immunizing lamprey with iPSC-derived BMEC-like cells, and inserting the resultant VLR repertoire into the yeast surface display system. Methods: The yeast displayed VLR library was then panned against human iPSC-derived BMEC-like cells and lead VLRs were validated using human in vitro models and mouse and human ex vivo brain tissue sections. Results: Finally, brain uptake for a set of VLRs was validated in mice. Of the 15 lead VLR candidates, 14 bound to human BBB antigens, and 10 bound to the murine BBB. Pharmacodynamic testing using the neuroactive peptide neurotensin indicated that the lead candidate, VLR2G, could cross the mouse BBB after intravenous injection and deliver sufficient neurotensin payload to generate a pharmacological response and lower systemic body temperature. Conclusions: Together, these results demonstrate the application of a novel screening technique capable of identifying a VLR with human relevance that can cross the BBB and deliver a payload. Full article

This review provides a mechanistic framework to strategically design nanoparticles capable of efficiently crossing the blood–brain barrier (BBB), a critical limitation in neurological treatments. We systematically analyze nanoparticle–BBB transport mechanisms, including receptor-mediated transcytosis, adsorptive-mediated transcytosis, and transient barrier modulation. Essential nanoparticle parameters (size, shape, stiffness, surface charge, and biofunctionalization) are evaluated for their role in enhancing brain targeting. For instance, receptor-targeted nanoparticles can significantly enhance brain uptake, achieving levels of up to 17.2% injected dose per gram (ID/g) in preclinical glioma models. Additionally, validated preclinical models (human-derived in vitro systems, rodents, and non-human primates) and advanced imaging techniques crucial for assessing nanoparticle performance are discussed. Distinct from prior BBB nanocarrier reviews that primarily catalogue mechanisms, this work (i) derives quantitative ‘design windows’ (size 10–100 nm, aspect ratio ~2–5, near-neutral ζ) linked to transcytosis efficiency, (ii) cross-walks human-relevant in vitro/in vivo models (including TEER thresholds and NHP evidence) into a translational decision guide, and (iii) integrates regulatory/toxicology readiness (ISO 10993-4, FDA/EMA, ICH) into practical checklists. We also curate recent (2020–2025) %ID/g brain-uptake data across lipidic, polymeric, protein, inorganic, and hybrid vectors to provide actionable, evidence-based rules for BBB design. Full article

Apolipoprotein A-I (apoA-I)-coated nanoemulsion particles target scavenger receptors. Adsorbed apoA-I (from the bloodstream) mediates/facilitates this targeted molecular contact, which is followed by receptor-mediated endocytosis and subsequent transcytosis of these same nanoemulsion (nanocarrier) particles across the blood–brain barrier (BBB). When the right drugs are added in advance to these high-density lipoprotein (HDL)-like nanocarriers, multifunctional combination treatment is achieved. This medication penetrates the BBB and targets particular cell-surface scavenger receptors, mainly class B type I (SR-BI). As a result, these (drug-carrying) nanoemulsions may find application in the biomedical therapy of complex medical disorders, such as dementia, as well as some aspects of aging. According to recent research, sustained inflammatory stimulation in the gut, such as via serum amyloid A (SAA), may cause the release of proinflammatory cytokines. Thus, using this “HDL-like” nanoemulsion vehicle to target drugs early (or even proactively) toward a major SAA receptor (like SR-BI), which is implicated in SAA-mediated cell-signaling processes that lead to aging and/or cognitive decline (and eventually Alzheimer’s disease or dementia), may be a useful preventive and therapeutic strategy. Full article

The increasing global health crisis of neurodegenerative diseases such as Alzheimer’s, Parkinson’s, amyotrophic lateral sclerosis, and Huntington’s disease is worsening because of a rapidly increasing aging population. Disease-modifying therapies continue to face development challenges due to the blood–brain barrier (BBB), which prevents more than 98% of small molecules and all biologics from entering the central nervous system. The therapeutic landscape for neurodegenerative diseases has recently undergone transformation through advances in targeted drug delivery that include ligand-decorated nanoparticles, bispecific antibody shuttles, focused ultrasound-mediated BBB modulation, intranasal exosomes, and mRNA lipid nanoparticles. This review provides an analysis of the molecular pathways that cause major neurodegenerative diseases, discusses the physiological and physicochemical barriers to drug delivery to the brain, and reviews the most recent drug targeting strategies including receptor-mediated transcytosis, cell-based “Trojan horse” approaches, gene-editing vectors, and spatiotemporally controlled physical methods. The review also critically evaluates the limitations such as immunogenicity, scalability, and clinical translation challenges, proposing potential solutions to enhance therapeutic efficacy. The recent clinical trials are assessed in detail, and current and future trends are discussed, including artificial intelligence (AI)-based carrier engineering, combination therapy, and precision neuro-nanomedicine. The successful translation of these innovations into effective treatments for patients with neurodegenerative diseases will require essential interdisciplinary collaboration between neuroscientists, pharmaceutics experts, clinicians, and regulators. Full article

The blood–brain barrier (BBB) is a highly selective and natural protective membrane that restricts the entry of therapeutic agents into the central nervous system (CNS). This restrictive nature poses a major challenge for pharmacological treatment of a wide range of CNS disorders, including neurodegenerative disorders, brain tumors, and psychiatric conditions. Many chemical drugs and biopharmaceuticals are unable to cross the BBB, and conventional drug delivery methods often fail to achieve sufficient brain concentrations, leading to reduced therapeutic efficacy and increased risk of systemic toxicity. In recent years, targeted drug delivery strategies have emerged as promising approaches to overcome the BBB and enhance the delivery of therapeutic agents to the brain. Among these, receptor-mediated transcytosis (RMT) and transporter-mediated transcytosis (TMT) are two of the most extensively studied mechanisms for transporting drugs across brain endothelial cells into the brain parenchyma. Advances in materials science and nanotechnology have facilitated the development of multifunctional carriers with optimized properties, improving drug targeting, stability, and release profiles within the brain. This review summarizes the physiological structure of the BBB and highlights recent innovations in RMT- and TMT-mediated brain drug delivery systems, emphasizing their potential not only to overcome current challenges in CNS drug development, but also to pave the way for next-generation therapies that enable more precise, effective, and personalized treatment of brain-related diseases. Full article

Background: Interleukin-15 (IL-15) stimulates the proliferation of natural killer cells or T cells, which, in combination with photodynamic therapy (PDT), has emerged as an effective strategy for cancer photoimmunotherapy. Instead of direct cytokine receptor activation, IL-15 necessitates first binding to the IL-15 receptor α chain subunit (IL-15Rα), followed by trans-presentation to the IL-15 receptor β/γ chain subunit on the effector cells for pharmacologic activation. Therefore, the delivery of IL-15 remains a major challenge owing to its short half-life, its lack of targeting activity, and the limited availability of IL-15Rα. Methods: A co-hitchhiking delivery approach using recombinant IL-15 (rIL-15) and a photosensitizer, pheophorbide A (PhA), is developed for enhanced combinatorial cancer immunotherapy with PDT. A recombinant IL-15Rα-sushi-Fc fusion protein (rILR-Fc) is designed to load rIL-15 through the IL-15Rα sushi domain, which mimics its trans-presentation. Moreover, the Fc moiety of rILR-Fc can load PhA based on its high binding affinity. Results: Through self-assembly, rILR-Fc/PhA/rIL-15 nanoparticles (NPs) are formulated to co-hitchhike PhA and rIL-15, which improves the tumor accumulation of PhA and rIL-15 through receptor-mediated transcytosis. Moreover, the nanoparticles prolong the blood half-life of rIL-15 but do not alter the elimination rate of PhA from the blood. The rILR-Fc/PhA/rIL-15 NPs effectively elicit potent systemic antitumor immunity and long-lasting immune memory against tumor rechallenge in model mice bearing orthotopic colon tumors. Conclusions: The enhanced antitumor therapeutic effect demonstrates that the co-hitchhiking delivery strategy, optimizing the pharmacokinetics of both the photosensitizer and IL-15, provides a promising strategy for combinatorial photodynamic and IL-15 immunotherapy. Full article

Low-density lipoprotein (LDL) chemically modified by reactive oxygen species (ROS), for example, leaking from red blood cells in the vascular compartment, more readily crosses the vascular endothelium than does nonoxidatively modified LDL to enter tissue fluid. Oxidatively modified LDL (oxLDL) may also be created in the tissue fluid by ROS leaking from cells by design, for example, by inflammatory white cells, or simply leaking from other cells as a consequence of oxygen metabolism. As well as oxLDL, glycatively modified LDL (glycLDL) is formed in the circulation. High-density lipoprotein (HDL) appears capable of decreasing the burden of lipid peroxides formed on LDL exposed to ROS or to glucose and its metabolites. The mechanism for this that has received the most attention is the antioxidant activity of HDL, which is due in large part to the presence of paraoxonase 1 (PON1). PON1 is intimately associated with its apolipoprotein A1 component and with HDL’s lipid domains into which lipid peroxides from LDL or cell membranes can be transferred. It is frequently overlooked that for PON1 to hydrolyze lipid substrates, it is essential that it remain by virtue of its hydrophobic amino acid sequences within a lipid micellar environment, for example, during its isolation from serum or genetically modified cells in tissue culture. Otherwise, it may retain its capacity to hydrolyze water-soluble substrates, such as phenyl acetate, whilst failing to hydrolyze more lipid-soluble molecules. OxLDL and probably glycLDL, once they have crossed the arterial endothelium by receptor-mediated transcytosis, are rapidly taken up by monocytes in a process that also involves scavenger receptors, leading to subendothelial foam cell formation. These are the precursors of atheroma, inducing more monocytes to cross the endothelium into the lesion and the proliferation and migration of myocytes present in the arterial wall into the developing lesion, where they transform into foam cells and fibroblasts. The atheroma progresses to have a central extracellular lake of cholesteryl ester following necrosis and apoptosis of foam cells with an overlying fibrous cap whilst continuing to grow concentrically around the arterial wall by a process involving oxLDL and glycLDL. Within the arterial wall, additional oxLDL is generated by ROS secreted by inflammatory cells and leakage from cells generally when couplet oxygen is reduced. PON1 is important for the mechanism by which HDL opposes atherogenesis, which may provide a better avenue of inquiry in the identification of vulnerable individuals and the provision of new therapies than have emerged from the emphasis placed on its role in RCT. Full article

The clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) system is a promising biotechnology tool for genome editing. However, in living organisms, several pharmacokinetic challenges arise, including off-target side effects due to incorrect distribution, low bioavailability caused by membrane impermeability, and instability resulting from enzymatic degradation. Therefore, innovative delivery strategies must be developed to address these issues. Modified nanoparticles offer a potential solution for the non-invasive delivery of CRISPR/Cas9 ribonucleoproteins (Cas9 RNPs). Cas9 RNPs encapsulated in nanoparticles are protected from enzymatic degradation, similar to how microRNAs are shielded within exosomes. It is well-established that certain materials, including proteins, are expressed selectively in specific cell types. For example, the α-7 nicotinic receptor is expressed in endothelial and neuronal cells, while the αvβ3 integrin is expressed in cancer cells. These endogenous materials can facilitate receptor-mediated endocytosis or transcytosis. Nanoparticles encapsulating Cas9 RNPs and coated with ligands targeting such receptors may be internalized through receptor-mediated mechanisms. Once internalized, Cas9 RNPs could perform the desired gene editing in the nucleus after escaping the endosome through mechanisms such as the proton sponge effect or membrane fusion. In this review, I discuss the potential and advantages of delivering Cas9 RNP-encapsulated nanoparticles coated with ligands through receptor-mediated endocytosis or transcytosis. Full article

Brain diseases pose significant treatment challenges due to the restrictive nature of the blood–brain barrier (BBB). Recent advances in targeting macromolecules offer promising avenues for overcoming these obstacles through receptor-mediated transcytosis (RMT). We summarize the current progress in targeting brain drug delivery with macromolecules for brain diseases. This exploration details the transport mechanisms across the BBB, focusing on RMT and its use of natural ligands for drug delivery. Furthermore, the review examines macromolecular ligands such as antibodies, peptides, and aptamers that leverage RMT for effective BBB traversal. Advancements in macromolecules-based delivery systems for brain diseases are summarized, emphasizing their therapeutic potential and limitations. Finally, emerging RMT strategies, including viral vectors, exosomes, and boron neutron capture therapy, are discussed for their precision in brain-targeted treatments. This comprehensive overview underscores the potential of RMT-based approaches to revolutionize brain disease therapy. Full article

Background: The blood–brain barrier (BBB) strictly regulates the penetration of substances into the brain, which, although important for maintaining brain homeostasis, may delay drug development because of the difficulties in predicting pharmacokinetics/pharmacodynamics (PKPD), toxicokinetics/toxicodynamics (TKTD), toxicity, safety, and efficacy in the central nervous system (CNS). Moreover, BBB functional proteins show species differences; therefore, humanized in vitro BBB models are urgently needed to improve the predictability of preclinical studies. Recently, international trends in the 3Rs in animal experiments and the approval of the FDA Modernization Act 2.0 have accelerated the application of microphysiological systems (MPSs) in preclinical studies, and in vitro BBB models have become synonymous with BBB–MPSs. Recently, we developed an industrialized humanized BBB–MPS, BBB–NET. In our previous report, we reproduced transferrin receptor (TfR)–mediated transcytosis with high efficiency and robustness, using hydrogels including fibrin and collagen I microfibers (CMFs). Methods: We investigated how adding CMFs to the fibrin gel benefits BBB-NETs. Results: We showed that CMFs accelerate capillary network formation and maturation by promoting astrocyte (AC) survival, and clarified that integrin β1 is involved in the mechanism of CMFs. Conclusions: Our data suggest that the quality control (QC) of CMFs is important for ensuring the stable production of BBB–NETs. Full article

The membrane impermeability of a drug poses a significant challenge in drug research and development, preventing effective drug delivery to the target site. Specifically, the blood-brain barrier (BBB) presents a formidable obstacle to the delivery of drugs targeting the central nervous system (CNS) into the brain, whereas the blood-retinal barrier (BRB) presents a tremendous obstacle to the delivery of drugs targeting the ocular diseases into the eyes. The development of drugs for Alzheimer’s or Parkinson’s disease targeting the CNS and for diabetic retinopathy and age-related macular degeneration targeting the eyes remains an unmet medical need for patients. Transporters play a crucial physiological role in maintaining homeostasis in metabolic organs. Various types of solute carrier (SLC) transporters are expressed in the capillary endothelial cells of the BBB, facilitating the delivery of nutrients from the blood flow to the brain. Therefore, carrier-mediated transport across the BBB can be achieved using SLC transporters present in capillary endothelial cells. It is well-known that CNS drugs typically incorporate N-containing groups, indicating that cation transporters facilitate their transport into the brain. In fact, carrier-mediated transport across the BBB can be accomplished using glucose transporter type 1 (Glut1) as a glucose transporter, L-type amino acid transporter 1 (LAT1) as a large neutral amino acid transporter, and H⁺/cation antiporter as a cation transporter. Surprisingly, although organic cation transporter novel type 2 (OCTN2) is expressed in the capillary endothelial cells, there has been limited investigation into OCTN2-mediated substance delivery into the brain across the BBB. Furthermore, it is suggested that OCTN2 is expressed at the BRB. In this prospective review, I present the advantages and possibilities of substance delivery into the brain across the BBB or into the eyes across the BRB, mediated by OCTN2 via carrier-mediated transport or receptor-mediated transcytosis. Full article