Angiopep-conjugated poly(ethylene glycol)-co-poly(ε-caprolactone) nanoparticles as dual-targeting drug delivery system for brain glioma

Think Big, Start Small: How Nanomedicine Could Alleviate the Burden of Rare CNS Diseases

The complexity and organization of the central nervous system (CNS) is widely modulated by the presence of the blood-brain barrier (BBB) and the blood-cerebrospinal fluid barrier (BCSFB), which both act as biochemical, dynamic obstacles impeding any type of undesirable exogenous exchanges. The disruption of these barriers is usually associated with the development of neuropathologies which can be the consequence of genetic disorders, local antigenic invasions, or autoimmune diseases. These disorders can take the shape of rare CNS-related diseases (other than Alzheimer's and Parkinson's) which a exhibit relatively low or moderate prevalence and could be part of a potential line of treatments from current nanotargeted therapies. Indeed, one of the most promising therapeutical alternatives in that field comes from the development of nanotechnologies which can be divided between drug delivery systems and diagnostic tools. Unfortunately, the number of studies dedicated to treating these rare diseases using nanotherapeutics is limited, which is mostly due to a lack of interest from industrial pharmaceutical companies. In the present review, we will provide an overview of some of these rare CNS diseases, discuss the physiopathology of these disorders, shed light on how nanotherapies could be of interest as a credible line of treatment, and finally address the major issues which can hinder the development of efficient therapies in that area.

Polymeric Nanoparticles-Based Brain Delivery with Improved Therapeutic Efficacy of Ginkgolide B in Parkinson's Disease

Purpose

Ginkgolide B (GB) is a terpene lactone derivative of Ginkgo biloba that is believed to function in a neuroprotective manner ideal for treating Parkinson’s disease (PD). Despite its promising therapeutic properties, GB has poor bioavailability following oral administration and cannot readily achieve sufficient exposure in treated patients, limiting its clinical application for the treatment of PD. In an effort to improve its efficacy, we utilized poly(ethylene glycol)-co-poly(ε-caprolactone) (PEG-PCL) nanoparticles as a means of encapsulating GB (GB-NPs). These NPs facilitated the sustained release of GB into the blood, thereby improving its ability to accumulate in the brain and to treat PD.

Methods and Results

Using Madin-Darby canine kidney (MDCK) cells, we were able to confirm that these NPs could be taken into cells via multiple nonspecific mechanisms including micropinocytosis, clathrin-dependent endocytosis, and lipid raft/caveolae-mediated endocytosis. Once internalized, these NPs tended to accumulate in the endoplasmic reticulum and lysosomes. In zebrafish, we determined that these NPs were readily able to undergo transport across the chorion, gastrointestinal, blood–brain, and blood-retinal barriers. In a 1-methyl-4-phenylpyridinium ion (MPP⁺)-induced neuronal damage model system, we confirmed the neuroprotective potential of these NPs. Following oral administration to rats, GB-NPs exhibited more desirable pharmacokinetics than did free GB, achieving higher GB concentrations in both the brain and the blood. Using a murine PD model, we demonstrated that these GB-NPs achieved superior therapeutic efficacy and reduced toxicity relative to free GB.

Conclusion

In conclusion, these results indicate that NPs encapsulation of GB can significantly improve its oral bioavailability, cerebral accumulation, and bioactivity via mediating its sustained release in vivo.

Angiopep-2 modified lipid-coated mesoporous silica nanoparticles for glioma targeting therapy overcoming BBB

Glioma is the most typical malignant brain tumor, and the chemotherapy to glioma is limited by poor permeability for crossing blood-brain-barrier (BBB) and insufficient availability. In this study, angiopep-2 modified lipid-coated mesoporous silica nanoparticle loading paclitaxel (ANG-LP-MSN-PTX) was developed to transport paclitaxel (PTX) across BBB mediated by low-density lipoprotein receptor-related protein 1 (LRP1), which is over-expressed on both BBB and glioma cells. ANG-LP-MSN-PTX was characterized with homogeneous hydrodynamic size, high drug loading capacity (11.08%) and a sustained release. In vitro experiments demonstrated that the targeting efficiency of PTX was enhanced by ANG-LP-MSN-PTX with higher penetration ability (10.74%) and causing more C6 cell apoptosis. ANG-LP-MSN-PTX (20.6%) revealed higher targeting efficiency compared with LP-MSN-PTX (10.6%) via blood and intracerebral microdialysis method in the pharmacokinetic study. The therapy of intracranial C6 glioma bearing rats was increasingly efficient, and ANG-LP-MSN-PTX could prolong the survival time of model rats. Taken together, ANG-LP-MSN-PTX might hold great promise as a targeting delivery system for glioma treatment.

Microbubbles and Nanobubbles with Ultrasound for Systemic Gene Delivery

The regulation of gene expression is a promising therapeutic approach for many intractable diseases. However, its use in clinical applications requires the efficient delivery of nucleic acids to target tissues, which is a major challenge. Recently, various delivery systems employing physical energy, such as ultrasound, magnetic force, electric force, and light, have been developed. Ultrasound-mediated delivery has particularly attracted interest due to its safety and low costs. Its delivery effects are also enhanced when combined with microbubbles or nanobubbles that entrap an ultrasound contrast gas. Furthermore, ultrasound-mediated nucleic acid delivery could be performed only in ultrasound exposed areas. In this review, we summarize the ultrasound-mediated nucleic acid systemic delivery system, using microbubbles or nanobubbles, and discuss its possibilities as a therapeutic tool.

Current Perspectives on Therapies, Including Drug Delivery Systems, for Managing Glioblastoma Multiforme

Glioblastoma multiforme (GBM), a standout among the most dangerous class of central nervous system (CNS) cancer, is most common and is an aggressive malignant brain tumor in adults. In spite of developments in modality therapy, it remains mostly incurable. Consequently, the need for novel systems, strategies, or therapeutic approaches for enhancing the assortment of active agents meant for GBM becomes an important criterion. Currently, cancer research focuses mainly on improving the treatment of GBM via diverse novel drug delivery systems. The treatment options at diagnosis are multimodal and include radiation therapy. Moreover, significant advances in understanding the molecular pathology of GBM and associated cell signaling pathways have opened opportunities for new therapies. Innovative treatment such as immunotherapy also gives hope for enhanced survival. The objective of this work was to collect and report the recent research findings to manage GBM. The present review includes existing novel drug delivery systems and therapies intended for managing GBM. Reported novel drug delivery systems and diverse therapies seem to be precise, secure, and relatively effective, which could lead to a new track for the obliteration of GBM.

Cell-penetrating peptides in oncologic pharmacotherapy: A review

Cancer is the second leading cause of death in the world and its treatment is extremely challenging, mainly due to its complexity. Cell-Penetrating Peptides (CPPs) are peptides that can transport into the cell a wide variety of biologically active conjugates (or cargoes), and are, therefore, promising in the treatment and in the diagnosis of several types of cancer. Some notable examples are TAT and Penetratin, capable of penetrating the central nervous system (CNS) and, therefore, acting in cancers of this system, such as Glioblastoma Multiforme (GBM). These above-mentioned peptides, conjugated with traditional chemotherapeutic such as Doxorubicin (DOX) and Paclitaxel (PTX), have also been shown to induce apoptosis of breast and liver cancer cells, as well as in lung cancer cells, respectively. In other cancers, such as esophageal cancer, the attachment of Magainin 2 (MG2) to Bombesin (MG2B), another CPP, led to pronounced anticancer effects. Other examples are CopA3, that selectively decreased the viability of gastric cancer cells, and the CPP p28. Furthermore, in preclinical tests, the anti-tumor efficacy of this peptide was evaluated on human breast cancer, prostate cancer, ovarian cancer, and melanoma cells in vitro, leading to high expression of p53 and promoting cell cycle arrest. Despite the numerous in vitro and in vivo studies with promising results, and the increasing number of clinical trials using CPPs, few treatments reach the expected clinical efficacy. Usually, their clinical application is limited by its poor aqueous solubility, immunogenicity issues and dose-limiting toxicity. This review describes the most recent advances and innovations in the use of CPPs in several types of cancer, highlighting their crucial importance for various purposes, from therapeutic to diagnosis. Further clinical trials with these peptides are warranted to examine its effects on various types of cancer.

Tailoring Iron Oxide Nanoparticles for Efficient Cellular Internalization and Endosomal Escape

Iron oxide nanoparticles (IONs) have been widely explored for biomedical applications due to their high biocompatibility, surface-coating versatility, and superparamagnetic properties. Upon exposure to an external magnetic field, IONs can be precisely directed to a region of interest and serve as exceptional delivery vehicles and cellular markers. However, the design of nanocarriers that achieve an efficient endocytic uptake, escape lysosomal degradation, and perform precise intracellular functions is still a challenge for their application in translational medicine. This review highlights several aspects that mediate the activation of the endosomal pathways, as well as the different properties that govern endosomal escape and nuclear transfection of magnetic IONs. In particular, we review a variety of ION surface modification alternatives that have emerged for facilitating their endocytic uptake and their timely escape from endosomes, with special emphasis on how these can be manipulated for the rational design of cell-penetrating vehicles. Moreover, additional modifications for enhancing nuclear transfection are also included in the design of therapeutic vehicles that must overcome this barrier. Understanding these mechanisms opens new perspectives in the strategic development of vehicles for cell tracking, cell imaging and the targeted intracellular delivery of drugs and gene therapy sequences and vectors.

Combined fluorescence-guided surgery and photodynamic therapy for glioblastoma multiforme using cyanine and chlorin nanocluster

INTRODUCTION

Glioblastoma multiforme (GBM) is the most common primary intracranial malignancy; survival can be improved by maximizing the extent-of-resection.

METHODS

A near-infrared fluorophore (Indocyanine-Green, ICG) was combined with a photosensitizer (Chlorin-e6, Ce6) on the surface of superparamagnetic-iron-oxide-nanoparticles (SPIONs), all FDA-approved for clinical use, yielding a nanocluster (ICS) using a microemulsion. The physical-chemical properties of the ICS were systematically evaluated. Efficacy of photodynamic therapy (PDT) was evaluated in vitro with GL261 cells and in vivo in a subtotal resection trial using a syngeneic flank tumor model. NIR imaging properties of ICS were evaluated in both a flank and an intracranial GBM model.

RESULTS

ICS demonstrated high ICG and Ce6 encapsulation efficiency, high payload capacity, and chemical stability in physiologic conditions. In vitro cell studies demonstrated significant PDT-induced cytotoxicity using ICS. Preclinical animal studies demonstrated that the nanoclusters can be detected through NIR imaging in both flank and intracranial GBM tumors (ex: 745 nm, em: 800 nm; mean signal-to-background 8.5 ± 0.6). In the flank residual tumor PDT trial, subjects treated with PDT demonstrated significantly enhanced local control of recurrent neoplasm starting on postoperative day 8 (23.1 mm3 vs 150.5 mm3, p = 0.045), and the treatment effect amplified to final mean volumes of 220.4 mm3 vs 806.1 mm3 on day 23 (p = 0.0055).

CONCLUSION

A multimodal theragnostic agent comprised solely of FDA-approved components was developed to couple optical imaging and PDT. The findings demonstrated evidence for the potential theragnostic benefit of ICS in surgical oncology that is conducive to clinical integration.

Nano delivery of natural substances as prospective autophagy modulators in glioblastoma

Glioblastoma is the most destructive type of malignant brain tumor in humans due to cancer relapse. Latest studies have indicated that cancer cells are more reliant on autophagy for survival than non-cancer cells. Autophagy is entitled as programmed cell death type II and studies imply that it is a comeback of cancer cells to innumerable anti-cancer therapies. To diminish the adverse consequences of chemotherapeutics, numerous herbs of natural origin have been retained in cancer treatments. Additionally, autophagy induction occurs via their tumor suppressive actions that could cause cell senescence and increase apoptosis-independent cell death. However, most of the drugs have poor solubility and thus nano drug delivery systems possess excessive potential to improve the aqueous solubility and bioavailability of encapsulated drugs. There is a pronounced need for more therapies for glioblastoma treatment and hereby, the fundamental mechanisms of natural autophagy modulators in glioblastoma are prudently reviewed in this article.

Understanding the Uptake of Nanomedicines at Different Stages of Brain Cancer Using a Modular Nanocarrier Platform and Precision Bispecific Antibodies

Increasing accumulation and retention of nanomedicines within tumor tissue is a significant challenge, particularly in the case of brain tumors where access to the tumor through the vasculature is restricted by the blood-brain barrier (BBB). This makes the application of nanomedicines in neuro-oncology often considered unfeasible, with efficacy limited to regions of significant disease progression and compromised BBB. However, little is understood about how the evolving tumor-brain physiology during disease progression affects the permeability and retention of designer nanomedicines. We report here the development of a modular nanomedicine platform that, when used in conjunction with a unique model of how tumorigenesis affects BBB integrity, allows investigation of how nanomaterial properties affect uptake and retention in brain tissue. By combining different in vivo longitudinal imaging techniques (including positron emission tomography and magnetic resonance imaging), we have evaluated the retention of nanomedicines with predefined physicochemical properties (size and surface functionality) and established a relationship between structure and tissue accumulation as a function of a new parameter that measures BBB leakiness; this offers significant advancements in our ability to relate tumor accumulation of nanomedicines to more physiologically relevant parameters. Our data show that accumulation of nanomedicines in brain tumor tissue is better correlated with the leakiness of the BBB than actual tumor volume. This was evaluated by establishing brain tumors using a spontaneous and endogenously derived glioblastoma model providing a unique opportunity to assess these parameters individually and compare the results across multiple mice. We also quantitatively demonstrate that smaller nanomedicines (20 nm) can indeed cross the BBB and accumulate in tumors at earlier stages of the disease than larger analogues, therefore opening the possibility of developing patient-specific nanoparticle treatment interventions in earlier stages of the disease. Importantly, these results provide a more predictive approach for designing efficacious personalized nanomedicines based on a particular patient's condition.

Mitigating off-target effects in CRISPR/Cas9-mediated in vivo gene editing

The rapid advancement of genome editing technologies has opened up new possibilities in the field of medicine. Nuclease-based techniques such as the CRISPR/Cas9 system are now used to target genetically linked disorders that were previously hard-to-treat. The CRISPR/Cas9 gene editing approach wields several advantages over its contemporary editing systems, notably in the ease of component design, implementation and the option of multiplex genome editing. While results from the early phase clinical trials have been encouraging, the small patient population recruited into these trials hinders a conclusive assessment on the safety aspects of the CRISPR/Cas9 therapy. Potential safety concerns include the lack of fidelity in the CRISPR/Cas9 system which may lead to unintended DNA modifications at non-targeted gene loci. This review focuses modifications to the CRISPR/Cas9 components that can mitigate off-target effects in in vitro and preclinical models and its translatability to gene therapy in patient populations.

Enhanced Anti-Glioma Efficacy by Borneol Combined With CGKRK-Modified Paclitaxel Self-Assembled Redox-Sensitive Nanoparticles

The serious therapeutic obstacles to glioma treatment include poor penetration across the blood-brain barrier (BBB) and low accumulation of therapeutic drugs at tumor sites. In this study, borneol combined with CGKRK peptide (a ligand of the heparan sulfate which overexpress on the glioma cells) modified paclitaxel prodrug self-assembled redox-responsive nanoparticles (CGKRK-PSNPs) were hypothesized to enhance the BBB penetration ability and active tumor targeting efficiency, respectively. The resulting CGKRK-PSNPs possessed a spherical shape with a small particle size (105.61 ± 1.53 nm) and high drug loading for PTX (54.18 ± 1.13%). The drug release behavior proved that CGKRK-PSNPs were highly sensitive to glutathione (GSH) redox environment. The in vitro cell experiments suggested that CGKRK-PSNPs significantly increased the cellular uptake and cytotoxicity of U87MG cells, meanwhile CGKRK-PSNPs showed the low cytotoxicity against BCEC cells. Combined with borneol, CGKRK-PSNPs exhibited enhanced transportation across in vitro BBB model. In intracranial U87MG glioma-bearing nude mice, the higher accumulation of CGKRK-PSNPs combined with borneol was observed through real-time fluorescence image. Moreover, the in vivo anti-glioma results confirmed that CGKRK-PSNPs combined with borneol could improve the anti-glioma efficacy with the prolonged medium survival time (39 days). In conclusion, the collaborative strategy of CGKRK-PSNPs combined with borneol provided a promising drug delivery routine for glioblastoma therapy.

Repolarization of glioblastoma macrophage cells using non-agonistic Dectin-1 ligand encapsulating TLR-9 agonist: plausible role in regenerative medicine against brain tumor

AIM OF THE STUDY

Glioblastoma multiforme (GBM) is the most severe forms of brain cancer, eventually becoming the leading cause of brain cancer-related death worldwide. Owing to the bleak surgical interventions and resistance to the different treatment regime, GBM is a parlous disease demanding newer therapeutical perspective for its treatment. Toll-like receptors (TLRs) are well-known members of pathogen recognition receptors (PRRs) and have been extensively explored for their therapeutic and prophylactic potential in an array of disease including cancer. Recent trends in drug delivery research has shown shift towards delivering short DNA sequences (CpG DNA) to endosomal TLR9 within immune cells (macrophages, dendritic cells, etc.) for the activation of desired inflammatory response using non-agonistic β-glucan particles; a well-known ligand for Dectin-1 receptors. Our study is therefore focused to explore the role of nano-encapsulated CpG ODN as critical players in polarizing M2 scavenging to much desired pro-inflammatory type.

MATERIALS AND METHODS

The nanoparticles entrapping CpG ODN 1826 were prepared by using a fungal polymer Schizophyllan (SPG). The constructed nanoparticles were characterized and assessed for their efficacy on rat glioblastoma cells (C6).

RESULTS

The constructed Schizophyllan (SPG) nanoparticles entrapping CpG ODN 1826 (95.3%) were of 25.49 nm in diameter and thus capable of crossing blood-brain barrier. The rat glioblastoma (C6) cells evaluated for intracellular oxidative burst and cytokine levels pre- and post-incubation with nanoparticles exhibited marked elevation in the expression of intracellular ROS and IFN-γ as well as IL-1β post treatment.

CONCLUSION

The findings indicate towards potentiality of repolarizing the M2 macrophages to much desired M1 phase by inducing higgh levels of oxidative burst and inflammatory cytokines. Consequently, the apoptosis was induced in glioblastoma cells establishing the suitablity of CpG ODN carrying nanoformulations as emerging therapeutic intervention for GBM.

AKT activation by SC79 to transiently re-open pathological blood brain barrier for improved functionalized nanoparticles therapy of glioblastoma

Glioblastoma (GBM) is one of the malignant tumors with high mortality, and the presence of the blood brain barrier (BBB) severely limits the penetration and tissue accumulation of therapeutic agents in the lesion of GBM. Active targeting nanotechnologies can achieve efficient drug delivery in the brain, while still have a very low success rate. Here we revealed a previously unexplored phenomenon that chemotherapy with active targeting nanotechnologies causes pathological BBB functional recovery through VEGF-PI3K-AKT signaling pathway inhibition, accompanied with up-regulated expression of Claudin-5 and Occludin. Seriously, pathological BBB functional recovery induces a significant decrease of intracerebral active targeting nanotechnologies transport during GBM multiple administration, leading to chemotherapy failure in GBM therapeutics. To address this issue, we chose AKT agonist SC79 to transiently re-open functional recovering pathological BBB for continuously intracerebral delivery of brain targeted nanotherapeutics, finally producing an observable anti-GBM effect in vivo, which may offer new sight for other CNS disease treatment.

PLGA-PEG-ANG-2 Nanoparticles for Blood-Brain Barrier Crossing: Proof-of-Concept Study

The treatment of diseases that affect the central nervous system (CNS) represents a great research challenge due to the restriction imposed by the blood-brain barrier (BBB) to allow the passage of drugs into the brain. However, the use of modified nanomedicines engineered with different ligands that can be recognized by receptors expressed in the BBB offers a favorable alternative for this purpose. In this work, a BBB-penetrating peptide, angiopep-2 (Ang-2), was conjugated to poly(lactic-co-glycolic acid) (PLGA)-based nanoparticles through pre- and post-formulation strategies. Then, their ability to cross the BBB was qualitatively assessed on an animal model. Proof-of-concept studies with fluorescent and confocal microscopy studies highlighted that the brain-targeted PLGA nanoparticles were able to cross the BBB and accumulated in neuronal cells, thus showing a promising brain drug delivery system.

Polymeric Nanoparticles for the Treatment of Malignant Gliomas

Malignant gliomas are one of the deadliest forms of brain cancer and despite advancements in treatment, patient prognosis remains poor, with an average survival of 15 months. Treatment using conventional chemotherapy does not deliver the required drug dose to the tumour site, owing to insufficient blood brain barrier (BBB) penetration, especially by hydrophilic drugs. Additionally, low molecular weight drugs cannot achieve specific accumulation in cancerous tissues and are characterized by a short circulation half-life. Nanoparticles can be designed to cross the BBB and deliver their drugs within the brain, thus improving their effectiveness for treatment when compared to administration of the free drug. The efficacy of nanoparticles can be enhanced by surface PEGylation to allow more specificity towards tumour receptors. This review will provide an overview of the different therapeutic strategies for the treatment of malignant gliomas, risk factors entailing them as well as the latest developments for brain drug delivery. It will also address the potential of polymeric nanoparticles in the treatment of malignant gliomas, including the importance of their coating and functionalization on their ability to cross the BBB and the chemistry underlying that.

PEGylated nanocarriers: A promising tool for targeted delivery to the brain

Targeted drug delivery across the blood-brain barrier is an extremely challenging quest in the fight with fatal brain ailments, with the major hurdles being short circulation time, reticuloendothelial system (RES) uptake, and excretion of nanocarriers. PEGylation has emerged as a boon for targeted drug delivery to the brain. It is well established that PEGylation can increase the circulation time of nanocarriers by avoiding RES uptake, which is indispensable for increasing the brain's uptake of nanocarriers. PEGylation also acts as a linker for ligand molecules to achieve active targeting to the brain. Using PEGylation, novel approaches are being investigated to facilitate ligand-receptor interactions at the brain endothelium to ease the entry of therapeutic drugs into the brain. In addition, PEGylation made it simpler to assess the brain tissue for delivering diagnostic molecules and theranostic nanocarriers. The potential of PEGylated nanocarriers is being investigated vastly to boost the therapeutic effect several fold in the treatment of brain diseases. This review sheds light on the contribution of PEGylated nanocarriers, especially liposomes, polymeric nanoparticles, and dendrimers for brain-specific delivery of bioactives.

Angiopep-2 conjugated nanoparticles loaded with doxorubicin for the treatment of primary central nervous system lymphoma

Primary central nervous system lymphoma (PCNSL) is a rare brain tumor. Its therapeutic efficacy is much lower than that of traditional lymphoma, largely due to the presence of the blood-brain barrier (BBB), which hinders the effective drug delivery and deposition on the disease site. Angiopep-2 (ANG) can target low-density lipoprotein receptor-related protein (LRP) on the surface of brain capillary endothelial cells (BCECs) and exhibits high BBB transport capability. In this study, we designed an ANG conjugated poly(ethylene glycol)-b-poly(ε-caprolactone) (PEG-b-PCL) (APP) nanoparticle to deliver doxorubicin (DOX) for the treatment of PCNSL. Our data indicated that the targeted APP nanoparticles showed significantly increased cellular uptake by BCECs compared with the control nanoparticles. In the intracranial SU-DHL-2-LUC lymphoma xenograft mice model, APP enhanced drug deposition in tumor tissues, and DOX-loaded APP (APP@DOX) exhibited a better therapeutic effect than free DOX and nontargeted PP@DOX, which significantly prolonged the survival time of mice.

Dual-targeting and excretable ultrasmall SPIONs for T1-weighted positive MR imaging of intracranial glioblastoma cells by targeting the lipoprotein receptor-related protein

A multifunctional targeted nanoprobe composed of ultrasmall superparamagnetic iron oxide nanoparticles with surface-conjugated Angiopep-2 was successfully constructed for targeted MR imaging of intracranial glioblastoma.

Key for crossing the BBB with nanoparticles: the rational design

Central nervous system diseases are a heavy burden on society and health care systems. Hence, the delivery of drugs to the brain has gained more and more interest. The brain is protected by the blood-brain barrier (BBB), a selective barrier formed by the endothelial cells of the cerebral microvessels, which at the same time acts as a bottleneck for drug delivery by preventing the vast majority of drugs to reach the brain. To overcome this obstacle, drugs can be loaded inside nanoparticles that can carry the drug through the BBB. However, not all particles are able to cross the BBB and a multitude of factors needs to be taken into account when developing a carrier system for this purpose. Depending on the chosen pathway to cross the BBB, nanoparticle material, size and surface properties such as functionalization and charge should be tailored to fit the specific route of BBB crossing.

Quantification and Evaluation of Glycyrrhizic Acid-loaded Surface Decorated Nanoparticles by UHPLC-MS/MS and used in the Treatment of Cerebral Ischemia

Background:

Glycyrrhizic Acid (GRA), a potent antioxidant triterpene saponin glycoside and neuroprotective properties exhibits an important role in the treatment of neurological disorders i.e. cerebral ischemia. GRA is water soluble, therefore it’s have low bioavailability in the brain.

Objective:

To enhance brain bioavailability for intranasally administered Glycyrrhizic Acidencapsulated- chitosan-coated-PCL-Nanoparticles (CS-GRA-PCL-NPs).

Methods:

Chitosan-coated-PCL-Nanoparticles (CS-PCL-NPs) were developed through double emulsification- solvent evaporation technique and further characterized for particle size, zeta potential, size distribution, encapsulation efficiency as well as in vitro drug release. UPLC triple quadrupole Qtrap MS/MS method was developed to evaluate brain-drug uptake for optimized CS-GRA-PCL-NPs and to determine its pharmacokinetic in rat’s brain as well as plasma.

Results:

Mean particles size (231.47±7.82), polydispersity index (PDI) i.e. (0.216±0.030) and entrapment efficiency (65.69±5.68) was determined for developed NPs. UPLC triple quadrupole Qtrap MS/MS method study showed a significantly high mucoadhesive potential of CS-GRA-PCL-NPs and least for conventional and homogenized nanoformulation; elution time for GRA and internal standard (IS) Hydrocortisone as 0.37 and 1.94 min at m/z 821.49/113.41 and 363.45/121.40 were observed, respectively. Furthermore, intra and inter-assay (%CV) of 0.49-5.48, %accuracy (90.00-99.09%) as well as a linear dynamic range (10.00 ng/mL -2000.0 ng/mL), was observed. Pharmacokinetic studies in Wistar rat brain exhibited a high AUC0-24 alongwith an amplified Cmax (p** < 0.01) as compared to i.v. treated group.

Conclusion:

Intranasal administration of developed CS-coated-GRA-loaded-PCL-NPs enhanced the drug bioavailability in rat brain along with successfully UPLC-MS/MS method and thus preparation of GRA-NPs may help treat cerebral ischemia effectively. The toxicity studies performed at the end revealed safe nature of optimized nanoformulation.

Dual and multi-targeted nanoparticles for site-specific brain drug delivery

In recent years, nanomedicines have emerged as a promising method for central nervous system drug delivery, enabling the drugs to overcome the blood-brain barrier and accumulate preferentially in the brain. Despite the current success of brain-targeted nanomedicines, limitations still exist in terms of the targeting specificity. Based on the molecular mechanism, the exact cell populations and subcellular organelles where the injury occurs and the drugs take effect have been increasingly accepted as a more specific target for the next generation of nanomedicines. Dual and multi-targeted nanoparticles integrate different targeting functionalities and have provided a paradigm for precisely delivering the drug to the pathological site inside the brain. The targeting process often involves the sequential or synchronized navigation of the targeting moieties, which allows highly controlled drug delivery compared to conventional targeting strategies. Herein, we focus on the up-to-date design of pathological site-specific nanoparticles for brain drug delivery, highlighting the dual and multi-targeting strategies that were employed and their impact on improving targeting specificity and therapeutic effects. Furthermore, the background discussion of the basic properties of a brain-targeted nanoparticle and the common lesion features classified by neurological pathology are systematically summarized.

Brain-targeted enzyme-loaded nanoparticles: A breach through the blood-brain barrier for enzyme replacement therapy in Krabbe disease

Lysosomal storage disorders (LSDs) result from an enzyme deficiency within lysosomes. The systemic administration of the missing enzyme, however, is not effective in the case of LSDs with central nervous system (CNS)-involvement. Here, an enzyme delivery system based on the encapsulation of cross-linked enzyme aggregates (CLEAs) into poly-(lactide-co-glycolide) (PLGA) nanoparticles (NPs) functionalized with brain targeting peptides (Ang2, g7 or Tf2) is demonstrated for Krabbe disease, a neurodegenerative LSD caused by galactosylceramidase (GALC) deficiency. We first synthesize and characterize Ang2-, g7- and Tf2-targeted GALC CLEA NPs. We study NP cell trafficking and capability to reinstate enzymatic activity in vitro. Then, we successfully test our formulations in the Twitcher mouse. We report enzymatic activity measurements in the nervous system and in accumulation districts upon intraperitoneal injections, demonstrating activity recovery in the brain up to the unaffected mice level. Together, these results open new therapeutic perspectives for all LSDs with major CNS-involvement.

Construction of Pepstatin A-Conjugated ultrasmall SPIONs for targeted positive MR imaging of epilepsy-overexpressed P-glycoprotein

Surgical resection of the epileptogenic region is typically regarded to be practical and efficient for complete elimination of intractable seizures, which cannot be simply controlled by anti-epileptic drugs alone. To achieve a precision removal of the epileptogenic region and even a surgical cure, molecular imaging of epilepsy markers is highly essential for non-invasive accurate detection of the epileptogenic region. In this work, a peptide-targeted nanoprobe, based on ultrasmall superparamagnetic iron oxide nanoparticles (USPIONs), PA-USPIONs, was elaborately constructed to enable highly selective delivery and sensitive T₁-weighted positive magnetic resonance (MR) imaging of the epileptogenic region. Especially, Pepstatin A (PA), a small peptide which can specifically target to P-glycoprotein (P-gp) overexpressed at the epileptogenic region in a kainic acid (KA)-induced mice model of seizures, was conjugated onto the surface of PEGylated USPIONs. It has been demonstrated that the as-constructed PA-USPIONs nanoprobes have favorable T₁ contrast enhancement and high r₁ relaxivity compared with the clinically used T₁-MR contrast agent (Gd-DTPA) by systematic in vitro and vivo assessments. Importantly, the toxicity evaluation, especially to brains, was assessed by the histological as well as hematological examinations, demonstrating that the fabricated PA-USPIONs nanoprobes are featured with excellent biocompatibility, guaranteeing the further potential clinical application. This first report on the development of USPIONs as T₁-weighted MR contrast agents for active targeting of the epileptogenic region holds the high potential for precise resection of the according lesion in order to achieve therapeutic, often curative purposes.

A window into the brain: Tools to assess pre-clinical efficacy of biomaterials-based therapies on central nervous system disorders

Therapeutic conveyance into the brain is a cardinal requirement for treatment of diverse central nervous system (CNS) disorders and associated pathophysiology. Effectual shielding of the brain by the blood-brain barrier (BBB) sieves out major proportion of therapeutics with the exception of small lipophilic molecules. Various nano-delivery systems (NDS) provide an effective solution around this obstacle owing to their small size and targeting properties. To date, these systems have been used for several pre-clinical disease models including glioma, neurodegenerative diseases and psychotic disorders. An efficacy screen for these systems involves a test battery designed to probe into the multiple facets of therapeutic delivery. Despite their wide application in redressing various disease targets, the efficacy evaluation strategies for all can be broadly grouped into four modalities, namely: histological, bio-imaging, molecular and behavioural. This review presents a comprehensive insight into all of these modalities along with their strengths and weaknesses as well as perspectives on an ideal design for a panel of tests to screen brain nano-delivery systems.

Selection of fluorescent dye for tracking biodistribution of paclitaxel in live imaging

Fluorescence imaging is widely used to determine biodistribution of drugs in mice. However, the dye distribution may not be able to exactly reflect the true distribution of drug molecules. We synthesized PTX-Cy5.5 and mPEG-PLA-Cy5.5, and then prepared dye-loaded nanoparticles (NPs) (Cy5.5, DiR, PTX-Cy5.5, and mPEG-PLA-Cy5.5), dye and PTX co-loaded NPs, and PTX-loaded NPs, respectively. The particle sizes of resulting NPs were between 42.7 nm and 68.8 nm, and Zeta potential was between -0.86 mV and -8.49 mV. The biodistribution of fluorescent NPs (dye-loaded NPs and dye and PTX co-loaded NPs) on Bel-7402 tumor-bearing mice was studied via in vivo fluorescence imaging assays, results of which suggested that Cy5.5 loaded NPs and Cy5.5 conjugates (PTX-Cy5.5 and mPEG-PLA-Cy5.5) formulated NPs can reflect the tissue distribution of PTX whether it was incorporated or not. However, DiR failed to reflect true tissue distribution of PTX unless it was co-loaded with PTX. Based on these results, a guidance for the selection of dyes in drug distribution investigations and disease-targeted treatment was presented.

Tumor targeting peptides: novel therapeutic strategies in glioblastoma

Peptides are a promising new therapeutic approach for glioblastoma with potential for more effective targeting and fewer devastating side effects compared to conventional cancer therapies. With the specificity to target receptors which are uniquely or overexpressed on cancer cells as well as accurately targeting dysregulated signaling pathways, peptides demonstrate a high potential for the treatment of even the most aggressive cancers. By binding to these targets, peptides can be used to deliver drugs, serve as antagonists to various ligands, or, given some inherent anticancer activity, provide additional treatment options alone or in combination therapy. The highly specific targeting capacity of peptides is critical to achieve effective cancer treatment with limited side effects, and in preclinical studies peptides have shown to have both cell and blood brain barrier penetrating capacity. As tumor targeting peptides move beyond the preclinical setting, identification of additional glioblastoma-specific peptide ligands becomes imperative to expand the potential of this encouraging treatment strategy.

Angiopep-2-Conjugated "Core-Shell" Hybrid Nanovehicles for Targeted and pH-Triggered Delivery of Arsenic Trioxide into Glioma

The poor capability of drugs to permeate through the blood-brain barrier (BBB) and further release inside glioma greatly limits the curative effects of glioma chemotherapies. In this study, we prepared angiopep-2-conjugated liposome-silica hybrid nanovehicles for targeted delivery and increased the permeation of arsenic trioxide (ATO) in glioma. Polyacrylic acid (PAA) was grafted on mesoporous silica nanoparticles (MSN) for pH-sensitive release and supporting the lipid membrane. The prepared "core-shell" nanovehicles (ANG-LP-PAA-MSN) were characterized with uniform size, high drug loading efficiency (8.19 ± 0.51%), and superior pH-sensitive release feature. From the experiments, the enhanced targeted delivery of ATO by ANG-LP-PAA-MSN (ANG-LP-PAA-MSN@ATO) was evidenced by the improvement of transport, enhanced cellular uptake, and apoptosis in vitro. In addition, the pharmacokinetic study was creatively carried out through the blood-glioma synchronous microdialysis and revealed that the half-life ( t_1/2) of blood and glioma tissue in the ANG-LP-PAA-MSN@ATO treatment group was extended by 1.65 and 2.34 times compared with the ATO solution group (ATO-Sol). The targeting efficiency of ANG-LP-PAA-MSN@ATO (24.96%) was dramatically stronger than that of the ATO-Sol (5.94%). Importantly, ANG-LP-PAA-MSN@ATO had a higher accumulation (4.6 ± 2.6% ID per g) in tumor tissues and showed a better therapeutic efficacy in intracranial C6 glioma bearing rats. Taken together, the blood-glioma synchronous microdialysis was successful used for the pharmacokinetic study and real-time monitoring of drug concentrations in blood and glioma; ANG-LP-PAA-MSN could be a promising targeted drug delivery system for glioma therapy.

Combination of Cell-Penetrating Peptides with Nanoparticles for Therapeutic Application: A Review

Cell-penetrating peptides (CPPs), also known as protein translocation domains, membrane translocating sequences or Trojan peptides, are small molecules of 6 to 30 amino acid residues capable of penetrating biological barriers and cellular membranes. Furthermore, CPP have become an alternative strategy to overcome some of the current drug limitations and combat resistant strains since CPPs are capable of delivering different therapeutic molecules against a wide range of diseases. In this review, we address the recent conjugation of CPPs with nanoparticles, which constitutes a new class of delivery vectors with high pharmaceutical potential in a variety of diseases.

Preparation and characterization of angiopep-2 functionalized Ginsenoside-Rg3 loaded nanoparticles and the effect on C6 Glioma cells

The purpose of this work was to prepare and characterize Angiopep-2 functionalized ginsenoside-Rg3 loaded nanoparticles (ANG-Rg3-NP) and evaluate the therapeutic effect on C6 glioma cells. Nanoparticles were prepared by the emulsion solvent evaporation method. Angiopep-2 was functionalized to nanoparticles via a maleimide-thiol covalent binding reaction to obtain ANG-Rg3-NP. The prepared nanoparticles were evaluated for size, zeta potential, morphology, stability, encapsulation efficiency, loading capacity, and release properties. The cytotoxicity study and targeting effect of ANG-Rg3-NP were evaluated by MTT assay. The study of cellular uptake in C6 glioma cells was performed by fluorescence microscopy and by using a microplate reader. The prepared ANG-Rg3-NP was observed to be uniformly spherical in shape with a particle size at 147.1 ± 2.7 nm. The encapsulation efficiency and loading capacity reached 80.6 ± 3.0% and 27.2 ± 1.4%, respectively. Additionally, ANG-Rg3-NP exhibited a desirable sustained release behavior. In vitro cytotoxicity study indicated that ANG-Rg3-NP could inhibit the proliferation of C6 glioma cells in a concentration-dependent manner. Also, the functionalization of Angiopep-2 made nanoparticles cross the blood-brain barrier more easily and accelerated the cellular uptake of nanoparticles. The ANG-Rg3-NP was a promising brain drug delivery carrier for the treatment of glioma.

Boosting RNAi therapy for orthotopic glioblastoma with nontoxic brain-targeting chimaeric polymersomes

Glioblastoma with intracranial infiltrative growth remains an incurable disease mainly owing to existence of blood brain barrier (BBB) and off-target drug toxicity. RNA interference (RNAi) with a high specificity and low toxicity emerges as a new treatment modality for glioblastoma. The clinical application of RNAi technology is, however, hampered by the absence of safe and brain-targeting transfection agents. Here, we report on angiopep-2 peptide-decorated chimaeric polymersomes (ANG-CP) as a nontoxic and brain-targeting non-viral vector to boost the RNAi therapy for human glioblastoma in vivo. ANG-CP shows excellent packaging and protection of anti-PLK1 siRNA (siPLK1) in its lumen while quickly releasing payloads in a cytoplasmic reductive environment. Notably, in vitro experiments demonstrate that ANG-CP can effectively permeate the bEnd.3 monolayer, transport siRNA into the cytosol of U-87 MG glioblastoma cells via the LRP-1-mediated pathway, and significantly silence PLK1 mRNA and corresponding oncoprotein in U-87 MG cells. ANG-CP greatly prolongs the siPLK1 circulation time and enhances its accumulation in glioblastoma. RNAi with siPLK1 induces a strong anti-glioblastoma effect and significantly improves the survival time of glioblastoma carrying mice.

Effective and Targeted Human Orthotopic Glioblastoma Xenograft Therapy via a Multifunctional Biomimetic Nanomedicine

Glioblastoma multiforme (GBM) is a fatal central nervous system tumor without effective treatment. Chemotherapeutic agents are mainstays in the treatment of glioblastoma. However, the effectiveness of these is seriously hindered by poor blood-brain-barrier (BBB) penetrance and tumor targeting, together with short biological half-life. Improved chemotherapy is thus urgently needed for GBM. Multifunctional nanoparticle delivery systems offer much promise in overcoming current limitations. Accordingly, a multifunctional biomimetic nanomedicine is developed by functionalizing the surface of red blood cell membranes (RBCms) with angiopep-2 and loading pH-sensitive nanoparticles (polymer, doxorubicin (Dox), and lexiscan (Lex)) using the functionalized cell membrane to generate the novel nanomedicine, Ang-RBCm@NM-(Dox/Lex). The studies toward orthotopic U87MG human glioblastoma tumor-bearing nude mice show that the Ang-RBCm@NM-(Dox/Lex) nanomedicine has much improved blood circulation time, superb BBB penetration, superior tumor accumulation and retention. Moreover, effective suppression of tumor growth and significantly improved medium survival time are also observed after Ang-RBCm@NM-(Dox/Lex) treatment. The results show that this biomimetic nanoplatform can serve as a flexible and powerful system for GBM treatment which can be readily adapted for the treatment of other central nervous system (CNS) disorders.

Therapeutic nanoplatforms and delivery strategies for neurological disorders

The major neurological disorders found in a central nervous system (CNS), such as brain tumors, Alzheimer's diseases, Parkinson's diseases, and Huntington's disease, have led to devastating outcomes on the human public health. Of these disorders, early diagnostics remains poor, and no treatment has been successfully discovered; therefore, they become the most life-threatening medical burdens worldwide compared to other major diseases. The major obstacles for the drug discovery are the presence of a restrictive blood-brain barrier (BBB), limiting drug entry into brains and undesired neuroimmune activities caused by untargeted drugs, leading to irreversible neuronal damages. Recent advances in nanotechnology have contributed to the development of novel nanoplatforms and effective delivering strategies to improve the CNS disorder treatment while less disturbing brain systems. The nanoscale drug carriers, including liposomes, dendrimers, viral capsids, polymeric nanoparticles, silicon nanoparticles, and magnetic/metallic nanoparticles, enable the effective drug delivery penetrating across the BBB, the aforementioned challenges in the CNS. Moreover, drugs encapsulated by the nanocarriers can reach further deeper into targeting regions while preventing the degradation. In this review, we classify novel disease hallmarks incorporated with emerging nanoplatforms, describe promising approaches for improving drug delivery to the disordered CNS, and discuss their implications for clinical practice.