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![Panel B: Gel filtration of supernatant trichloroacetic acid (TCA) precipitable radioactivity following a 10-min internal 125 carotid artery perfusion of I-b-endorphin. The TCA-precipitable pellet obtained from brain homogenate was solubilized in 6 M guanidine and eluted over a Superose I2HR FPLC column. The radioactivity in collected fractions is shown on the ordinate. 6 Molecular weight standards are (1) blue dextran (2310 Da), (2) bovine serum albumin (68 000 Da), (3) ribonuclease A (13 700 125 Da). Panel A: The elution profile of I-b-endorphin standard. All of the radioactivity present in the TCA precipitable fraction of brain homogenate is associated with high-molecular-weight products and no intact 13-endorphin is taken up by brain. From Ref. [30].](profile/William-Pardridge/publication/12072599/figure/fig2/AS:626931586330627@1526483546436/Panel-B-Gel-filtration-of-supernatant-trichloroacetic-acid-TCA-precipitable.png)
Panel B: Gel filtration of supernatant trichloroacetic acid (TCA) precipitable radioactivity following a 10-min internal 125 carotid artery perfusion of I-b-endorphin. The TCA-precipitable pellet obtained from brain homogenate was solubilized in 6 M guanidine and eluted over a Superose I2HR FPLC column. The radioactivity in collected fractions is shown on the ordinate. 6 Molecular weight standards are (1) blue dextran (2310 Da), (2) bovine serum albumin (68 000 Da), (3) ribonuclease A (13 700 125 Da). Panel A: The elution profile of I-b-endorphin standard. All of the radioactivity present in the TCA precipitable fraction of brain homogenate is associated with high-molecular-weight products and no intact 13-endorphin is taken up by brain. From Ref. [30].
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Peptide and protein therapeutics are generally excluded from transport from blood to brain, owing to the negligible permeability of these drugs to the brain capillary endothelial wall, which makes up the blood-brain barrier (BBB) in vivo. However, peptides or protein therapeutics may be delivered to the brain with the use of the chimeric peptide st...
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Context 1
... a gel filtration fast protein liquid chromatography pharmacokinetic evaluation. This statement is sup- (FPLC) column, however, revealed that the activity ported by the fact that even with the perfusion completely eluted in high-molecular-weight fractions 125 technique, where there is no exposure of the test and none coeluted with I-b-endorphin (Fig. 4). substance to plasma enzymes, considerable degra- This result can be explained by the known presence by brain in vivo by millimolar concentrations of unlabeled tyrosine [33] and the inhibition of TRH uptake by the inclusion of the peptidase inhibitor bacitracin in the perfusate ...
Context 2
... receptor (TfR) at trafiltration technique, and these studies show that an epitope that is removed from the transferrin (Tf) 2.3 biotin binding sites were present per avidin- binding site to trigger receptor-mediated transcytosis OX26 conjugate. The conjugate was used to demon- through the BBB. As shown in Table 3, the addition As shown in Fig. 14, the brain is greatly enriched in 5. Delivery of peptide or protein therapeutics to disulfide reductases that rapidly remove a b-endor- brain phin therapeutic from a cationized albumin vector. The b-endorphin was thiolated at the amino terminal 5.1. Chimeric peptides group using SPDP. Consequently, when the disulfide bridge is cleaved, ...
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Recombinant protein therapeutics cannot enter brain drug development because these large molecule drugs do not cross the blood-brain barrier (BBB). However, recombinant proteins can be reengineered as BBB-penetrating IgG fusion proteins, where the IgG part is a genetically engineered monoclonal antibody (MAb) against an endogenous BBB receptor, suc...
Citations
... The transport of peptides and small proteins is one of the applications of chitosan nanohydrogels. Because of the properties such as smaller size, lower toxicity, and easy passage through blood vessels, the use of peptides and small proteins has been expanded [9][10][11]. In a study by Soni and Yadav it has been shown that nanohydrogels have a very high drug loading capacity and controlled release by adjusting lattice densities in polymers (up to 50% loading efficiency, which includes to nanoparticles such as Micelles, biodegradable nanoparticles, liposomes or nanocapsules) [12]. ...
In this study, the process of manufacturing nanohydrogels containing papain and how to release it was investigated. Chitosan nanohydrogels and chitosan–polyethylene glycol hybrid nanohydrogels were used to entrapment of papain as a protein model. In order to evaluate and confirm different properties of nanohydrogels such as size, shape, the rate of swelling and flexibility, different methods was used. The maximum amount of papain entrapment was observed in 0.75% concentration of chitosan and 1% concentration of sodium Tripolyphosphate (TPP) as linker. The results of scanning electron microscope (SEM) and X-ray diffraction (XRD) patterns showed that nanohydrogels containing papain on a nano scale are very porous and swollen. Differential scanning calorimetry (DSC) thermograms analysis showed that nanohydrogels have relatively good water absorption capacity. Also, by adding polyethylene glycol to chitosan, the melting temperature of hybrid nanohydrogels decreased and this can be a reason for the formation of flexible structures in these nanohydrogels. In chitosan nanohydrogels, the highest release rate of papain was observed at pH lower than 7 and high temperatures, but by adding polyethylene glycol to the chitosan, in addition to increasing papain release, a proper and continuous release of papain was observed at temperature and pH close to physiological conditions, especially at low ratios of polyethylene glycol. According to the present results, hybrid nanohydrogels can have a good potential in protein delivery systems in terms of structure and release.
... Secondly, peptide binding to the glycocalyx would generate larger numbers of 'artificial' targets, as occupancy of the glycocalyx is expected to be saturated at higher concentrations than for specific cell-membrane proteins. As such, adsorptive-mediated transcytosis (AMT), a transport mechanism based on unspecific binding to the cell-surface due to electrostatic interaction, is known to be saturated at concentrations several orders of magnitude higher than receptor-mediated transcytosis (RMT), a transport mechanism based on binding to specific cell-membrane proteins [4,14], with saturation constants calculated in the micromolar range. Such glycocalyx binding may explain the lack of complete saturation of CFAG peptide binding even at micromolar concentrations. ...
Current strategies to identify ligands for brain delivery select candidates based on preferential binding to cell-membrane components (CMC) on brain endothelial cells (EC). However, such strategies generate ligands with inherent brain specificity limitations, as the CMC (e.g., the transferrin receptor TfR1) are also significantly expressed on peripheral EC. Therefore, novel strategies are required to identify molecules allowing increased specificity of therapy brain delivery. Here, we demonstrate that, while individual CMC are shared between brain EC and peripheral EC, their endocytic internalization rate is markedly different. Such differential endocytic rate may be harnessed to identify molecular tags for brain targeting based on their selective retention on the surface of brain EC, thereby generating ‘artificial’ targets specifically on the brain vasculature. By quantifying the retention of labelled proteins on the cell membrane, we measured the general endocytic rate of primary brain EC to be less than half that of primary peripheral (liver and lung) EC. In addition, through bio-panning of phage-displayed peptide libraries, we unbiasedly probed the endocytic rate of individual CMC of liver, lung and brain endothelial cells. We identified phage-displayed peptides which bind to CMC common to all three endothelia phenotypes, but which are preferentially endocytosed into peripheral EC, resulting in selective retention on the surface of brain EC. Furthermore, we demonstrate that the synthesized free-form peptides are capable of generating artificial cell-surface targets for the intracellular delivery of model proteins into brain EC with increasing specificity over time. The developed identification paradigm, therefore, demonstrates that the lower endocytic rate of individual CMC on brain EC can be harnessed to identify peptides capable of generating ‘artificial’ targets for the selective delivery of proteins into the brain vasculature. In addition, our approach identifies brain-targeting peptides which would have been overlooked by conventional identification strategies, thereby increasing the repertoire of candidates to achieve specific therapy brain delivery.
Supplementary Information
The online version contains supplementary material available at 10.1186/s12987-023-00493-6.
... AD: Alzheimer's disease; APP: amyloid precursor protein; Aβ: amyloid-β; BACE1: beta-site amyloid precursor protein cleaving enzyme 1; BDNF: brain-derived neurotrophic factor; GSK3β: glycogen synthase kinase 3β; NgR: Nogo receptor; PEG: polyethylene glycol; siRNA: small interfering ribonucleic acid; TAT: transactivator of transcription. Bickel et al., 2001;Boado et al., 2007Boado et al., , 2011Kabanov et al., 2007;Pardgridge et al., 2008Pardgridge et al., , 2010 Cubosome NPs with omega-3 fatty acid BDNF In vitro Géral et al., 2012 6 NTS ( AD: Alzheimer's disease; BDNF: brain-derived neurotrophic factor; GDNF: glial cell-derived neurotrophic factor; NGF: nerve growth factor; NPs: nanoparticles; PEG: polyethylene glycol; Tat: transactivator of transcription. ...
Toxic aggregated amyloid-β accumulation is a key pathogenic event in Alzheimer's disease. Treatment approaches have focused on the suppression, deferral, or dispersion of amyloid-β fibers and plaques. Gene therapy has evolved as a potential therapeutic option for treating Alzheimer's disease, owing to its rapid advancement over the recent decade. Small interfering ribonucleic acid has recently garnered considerable attention in gene therapy owing to its ability to down-regulate genes with high sequence specificity and an almost limitless number of therapeutic targets, including those that were once considered undruggable. However, lackluster cellular uptake and the destabilization of small interfering ribonucleic acid in its biological environment restrict its therapeutic application, necessitating the development of a vector that can safeguard the genetic material from early destruction within the bloodstream while effectively delivering therapeutic genes across the blood-brain barrier. Nanotechnology has emerged as a possible solution, and several delivery systems utilizing nanoparticles have been shown to bypass key challenges regarding small interfering ribonucleic acid delivery. By reducing the enzymatic breakdown of genetic components, nanomaterials as gene carriers have considerably enhanced the efficiency of gene therapy. Liposomes, polymeric nanoparticles, magnetic nanoparticles, dendrimers, and micelles are examples of nanocarriers that have been designed, and each has its own set of features. Furthermore, recent advances in the specific delivery of neurotrophic compounds via gene therapy have provided promising results in relation to augmenting cognitive abilities. In this paper, we highlight the use of different nanocarriers in targeted gene delivery and small interfering ribonucleic acid-mediated gene silencing as a potential platform for treating Alzheimer's disease.
... For example, glucose uptake is achieved by means of GLUT1, a glucose-transporter, a recent study showing a correlation between neurodegeneration and GLUT1 reduced brain levels (Winkler et al. 2015). Other transporters localized on luminal and abluminal membranes of BMECs have also been reported for the transport of amino acids such as valine, histidine, alanine, serine, cysteine, etc. b) Absorptive-Mediated Transcytosis (AMT): Endocytosis is initiated by electrostatic interactions of positively charged molecules such as peptides and proteins with negatively charged parts of the membrane which then permit transcytosis (Bickel et al. 2001). This pathway for BBB penetration is characterized by very low specificity but better capacity. ...
... 10,11 The utilization of TfR-mediated transcytosis to cross the BBB for brain delivery of large molecule biologics was originally proposed and verified by Pardridge and colleagues. [12][13][14][15][16][17] We recently developed another BBB-penetrating fusion protein targeting TfR designated pabinafusp alfa (JR-141), which has been approved and marketed in Japan for treating all forms of MPS II, including neuronopathic. [18][19][20][21][22][23] Here, we conducted a nonclinical evaluation of JR-171 using a murine MPS I model and cynomolgus monkeys to elucidate its pharmacological effects on substrate deposition, histopathological changes, and neurobehavioral abnormality, as well as biodistribution, pharmacokinetics, and safety. ...
... The basic concept of BBB penetration of large molecule drugs using receptor-mediated transcytosis was proposed and verified by Pardridge and colleagues. [12][13][14][15][16][17] Although the BBB restricts molecular and cellular transport from the bloodstream into the brain parenchyma, several proteins, including leptin, insulin, and transferrin, penetrate the BBB by binding to their specific receptors on the surface of the capillary endothelial cells in the brain. [24][25][26] Anti-insulin receptor antibody and anti-TfR antibody can be used as a carrier/vehicle of drugs to be delivered to the brain. ...
Mucopolysaccharidosis I (MPS I), a lysosomal storage disease caused by dysfunction of α-L-iduronidase (IDUA), is characterized by the deposition of dermatan sulfate (DS) and heparan sulfate (HS) throughout the body, which causes several somatic and central nervous symptoms. Although enzyme-replacement therapy (ERT) is currently available to treat MPS I, it does not alleviate central nervous disorders, as it cannot penetrate the blood-brain barrier. Here we evaluate the brain delivery, efficacy, and safety of JR-171, a fusion protein comprising humanized anti-human transferrin receptor antibody Fab and IDUA, using monkeys and MPS I mice. Intravenously administered JR-171 was distributed in major organs, including the brain, and reduced DS and HS concentrations in the central nervous system and peripheral tissues. JR-171 exerted similar effects on peripheral disorders similar to conventional ERT and further reversed brain pathology in MPS I mice. We found that JR-171 improved spatial learning ability, which was seen to deteriorate in the vehicle-treated mice. Further, no safety concerns were noted in repeat-dose toxicity studies in monkeys. This study provides nonclinical evidence that JR-171 might potentially prevent and even improve disease conditions in patients with neuronopathic MPS I without serious safety concerns.
... One possible mechanism is transcytosis through the BBB, whereby peptide hormones are received by specific receptors or binding proteins at the surface of the BBB and transported to the other side of the cells through vesicle trafficking. This hypothesis has been proposed for transport of many peptide hormones through the BBB in mammals and other species [253,254], although available pieces of evidence are still controversial. Another possibility is that peptide hormones act through the neurohemalreleasing sites of target neurosecretory cells. ...
In multicellular organisms, endocrine factors such as hormones and cytokines regulate development and homoeostasis through communication between different organs. For understanding such interorgan communications through endocrine factors, the fruit fly Drosophila melanogaster serves as an excellent model system due to conservation of essential endocrine systems between flies and mammals and availability of powerful genetic tools. In Drosophila and other insects, functions of neuropeptides or peptide hormones from the central nervous system have been extensively studied. However, a series of recent studies conducted in Drosophila revealed that peptide hormones derived from peripheral tissues also play critical roles in regulating multiple biological processes, including growth, metabolism, reproduction, and behaviour. Here, we summarise recent advances in understanding target organs/tissues and functions of peripherally derived peptide hormones in Drosophila and describe how these hormones contribute to various biological events through interorgan communications. © 2022 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
... However, due to its short half-life and drawback of demonstrating additive hypoglycemia action with endogenous insulin, it is not regarded as a suitable vector to transport medicines into the CNs. When using insulin growth factor or IR monoclonal antibodies, this difficulty does not arise [85]. Human anti-insulin receptor monoclonal antibody was used in an experiment on Rhesus monkeys to shuttle a TNF-α decoy to treat anti-inflammatory diseases [86]. ...
It is well known that the presence of a blood–brain barrier (BBB) makes drug delivery to the brain more challenging. There are various mechanistic routes through which therapeutic molecules travel and deliver the drug across the BBB. Among all the routes, the transcellular route is widely explored to deliver therapeutics. Advances in nanotechnology have encouraged scientists to develop novel formulations for brain drug delivery. In this article, we have broadly discussed the BBB as a limitation for brain drug delivery and ways to solve it using novel techniques such as nanomedicine, nose-to-brain drug delivery, and peptide as a drug delivery carrier. In addition, the article will help to understand the different factors governing the permeability of the BBB, as well as various formulation-related factors and the body clearance of the drug delivered into the brain.
... ,20,21 Solid lipid nanoparticles and nanostructured lipid carriers to target brain tumors Advanced Pharmaceutical Bulletin, 2023, Volume 13, Issue 3 ...
Brain, predisposed to local and metastasized tumors, has always been the focus of oncological studies. Glioblastoma Multiforme (GBM), the most common invasive primary tumor of the brain, is responsible for 4% of all cancer-related deaths worldwide. Despite novel technologies, the average survival rate is 2 years. Physiological barriers such as blood-brain barrier (BBB) prevent drug molecules penetration into brain. Most of the pharmaceuticals present in the market cannot infiltrate BBB to have their maximum efficacy and this in turn imposes a major challenge. This mini review discusses GBM and physiological and biological barriers for anticancer drug delivery, challenges for drug delivery across BBB, drug delivery strategies focusing on SLNs and NLCs and their medical applications in on-going clinical trials. Numerous nanomedicines with various characteristics have been introduced in the last decades to overcome the delivery challenge. Solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) were introduced as oral drug delivery nanomedicines which can be encapsulated by both hydrophilic and lipophilic pharmaceutical compounds. Their biocompatibility, biodegradability, lower toxicity and side effects, enhanced bioavailability, solubility and permeability, prolonged half-life and stability and finally tissue-targeted drug delivery makes them unique among all.
... To overcome this barrier, multiple approaches have been developed to deliver neurotherapeutic agents to the brain. Receptor-, adsorptive-, and carrier-mediated transport systems have been introduced in recent years for delivering neuroprotective proteins and peptides to the brain [71,72]. Studies have shown that these noninvasive approaches could increase the permeability of the peptide through the BBB, which can resolve the drug delivery problem [71,72]. ...
... Receptor-, adsorptive-, and carrier-mediated transport systems have been introduced in recent years for delivering neuroprotective proteins and peptides to the brain [71,72]. Studies have shown that these noninvasive approaches could increase the permeability of the peptide through the BBB, which can resolve the drug delivery problem [71,72]. For instance, receptor-meditated transcytosis (RMT) can transport certain proteins (e.g., insulin, transferrin, and leptin) through the BBB via corresponding endogenous receptors [22], which indicates that our peptide, which was predicted to bind with ion channel, could be delivered to the brain through RMT. ...
Alzheimer’s disease (AD) is a progressive and irreversible neurodegenerative disorder for which there is no effective therapeutic strategy. PcActx peptide from the transcriptome of zoantharian Palythoa caribaeorum has recently been identified and verified as a novel antagonist of transient receptor potential cation channel subfamily V member 1 (TRPV1). In the present study, we further investigated the neuroprotective potential of PcActx peptide and its underlying mechanism of action, in an N2a/APP cell model of AD. Both Western blot and RT-PCR analysis revealed that PcActx peptide markedly inhibited the production of amyloid-related proteins and the expression of BACE1, PSEN1, and PSEN2. Moreover, PcActx peptide notably attenuated the capsaicin-stimulated calcium response and prevented the phosphorylation of CaMKII and CaMKIV (calcium-mediated proteins) in N2a/APP cells. Further investigation indicated that PcActx peptide significantly suppressed ROS generation through Nrf2 activation, followed by enhanced NQO1 and HO-1 levels. In addition, PcActx peptide remarkably improved Akt phosphorylation at Ser 473 (active) and Gsk3β phosphorylation at Ser 9 (inactive), while pharmacological inhibition of the Akt/Gsk3β pathway significantly attenuated PcActx-induced Nrf2 activation and amyloid downregulation. In conclusion, PcActx peptide functions as a TRPV1 modulator of intercellular calcium homeostasis, prevents AD-like amyloid neuropathology via Akt/Gsk3β-mediated Nrf2 activation, and shows promise as an alternative therapeutic agent for AD.
... Using cationic amino groups to alter bovine serum albumin, new activities were added to the protein without affecting its structure. On account of CBSA's positive charge, which makes it easier for it to pass exosome membranes, the optimum pI values of CBSA have been widely studied as a siRNA carrier (Bickel et al., 2001;Han et al., 2014). Furthermore, CBSA/siRNA@Exosome showed excellent biocompatibility and very robust suppression of lung metastases as a result of the elevated accumulation in pulmonary PMN of siRNA via organotropopism mediated by exosome membranes. ...
siRNA interference, commonly referred to as gene silence, is a biological mechanism that inhibits gene expression in disorders such as cancer. It may enhance the precision, efficacy, and stability of medicines, especially genetic therapies to some extent. However, obstacles such as the delivery of oligonucleotide drugs to inaccessible areas of the body and the prevalence of severe side effects must be overcome. To maximize their potential, it is thus essential to optimize their distribution to target locations and limit their toxicity to healthy cells. The action of siRNA may be harnessed to delete a similar segment of mRNA that encodes a protein that causes sickness. The absence of an efficient delivery mechanism that shields siRNA from nuclease degradation, delivers it to cancer cells and releases it into the cytoplasm of specific cancer cells without causing side effects is currently the greatest obstacle to the practical implementation of siRNA therapy. This article focuses on combinations of siRNA with chemotherapeutic drug delivery systems for the treatment of cancer and gives an overview of several nanocarrier formulations in both research and clinical applications.
