Optimizing long-term stability of siRNA using thermoassemble ionizable reverse pluronic-Bcl2 micelleplexes

Thermosassemble Ionizable Reverse Pluronic (TIRP) platform stands out for its distinctive combination of thermoassemble and ionizable features, effectively overcoming challenges in previous siRNA delivery systems. This study opens up a formation for long-term stabilization, and high loading of siRNA, specifically crafted for targeting oncogenic pathways. TIRP-Bcl2 self-assembles into a unique micelle structure with a nanodiameter of 75.8 ± 5.7 nm, efficiently encapsulating Bcl2 siRNA while maintaining exceptional colloidal stability at 4 °C for 8 months, along with controlled release profiles lasting 180 h. The dual ionizable headgroup enhance the siRNA loading and the revers pluronic unique structural orientation enhance the stability of the siRNA. The thermoassemble of TIRP-Bcl2 facilitates flexi-rigid response to mild hyperthermia, enhancing deep tissue penetration and siRNA release in the tumor microenvironment. This responsive behavior improves intracellular uptake and gene silencing efficacy in cancer cells. TIRP, with its smaller particle size and reverse pluronic nature, efficiently transports siRNA across the blood-brain barrier, holding promise for revolutionizing glioblastoma (GBM) treatment. TIRP-Bcl2 shows significant potential for precise, personalized therapies, promising prolonged siRNA delivery and in vitro/in vivo stability. This research opens avenues for further exploration and clinical translation of this innovative nanocarrier system across different cancers.

Bioreducible exosomes encapsulating glycolysis inhibitors potentiate mitochondria-targeted sonodynamic cancer therapy via cancer-targeted drug release and cellular energy depletion

Nanocarrier-assisted sonodynamic therapy (SDT) has shown great potential for the effective and targeted treatment of deep-seated tumors by overcoming the critical limitations of sonosensitizers. However, in vivo SDT using nanocarriers is still constrained by their intrinsic toxicity and nonspecific cargo release. In this study, we developed bioreducible exosomes for the safe and tumor-specific delivery of mitochondria-targeting sonosensitizers [triphenylphosphonium-conjugated chlorin e6 (T-Ce6)] and glycolysis inhibitors (FX11). Redox-cleavable diselenide linker-bearing lipids were embedded into exosomes to trigger drug release in response to overexpressed glutathione in the tumor microenvironment. Bioreducible exosomes facilitate the cytoplasmic release of their payload in the reducing environment of tumor cells. They significantly enhance drug release and sonodynamic effects when irradiated with ultrasound (US). The mitochondria-targeted accumulation of T-Ce6 efficiently damaged the mitochondria of the cells under US irradiation, accelerating apoptotic cell death. FX11 substantially inhibited cellular energy metabolism, potentiating the antitumor efficacy of mitochondria-targeted SDT. Bioreducible exosomes effectively suppressed tumor growth in mice without significant systemic toxicity, via a combination of mitochondria-targeted SDT and energy metabolism-targeted therapy. This study offers new insights into the use of dual stimuli-responsive exosomes encapsulating sonosensitizers for safe and targeted sonodynamic cancer therapy.

Brain endothelial cell-derived extracellular vesicles with a mitochondria-targeting photosensitizer effectively treat glioblastoma by hijacking the blood‒brain barrier

Glioblastoma (GBM) is the most aggressive malignant brain tumor and has a high mortality rate. Photodynamic therapy (PDT) has emerged as a promising approach for the treatment of malignant brain tumors. However, the use of PDT for the treatment of GBM has been limited by its low blood‒brain barrier (BBB) permeability and lack of cancer-targeting ability. Herein, brain endothelial cell-derived extracellular vesicles (bEVs) were used as a biocompatible nanoplatform to transport photosensitizers into brain tumors across the BBB. To enhance PDT efficacy, the photosensitizer chlorin e6 (Ce6) was linked to mitochondria-targeting triphenylphosphonium (TPP) and entrapped into bEVs. TPP-conjugated Ce6 (TPP-Ce6) selectively accumulated in the mitochondria, which rendered brain tumor cells more susceptible to reactive oxygen species-induced apoptosis under light irradiation. Moreover, the encapsulation of TPP-Ce6 into bEVs markedly improved the aqueous stability and cellular internalization of TPP-Ce6, leading to significantly enhanced PDT efficacy in U87MG GBM cells. An in vivo biodistribution study using orthotopic GBM-xenografted mice showed that bEVs containing TPP-Ce6 [bEV(TPP-Ce6)] substantially accumulated in brain tumors after BBB penetration via transferrin receptor-mediated transcytosis. As such, bEV(TPP-Ce6)-mediated PDT considerably inhibited the growth of GBM without causing adverse systemic toxicity, suggesting that mitochondria are an effective target for photodynamic GBM therapy.

Piezocatalytic 2D WS2 Nanosheets for Ultrasound-Triggered and Mitochondria-Targeted Piezodynamic Cancer Therapy Synergized with Energy Metabolism-Targeted Chemotherapy

Piezoelectric nanomaterials that can generate reactive oxygen species (ROS) by piezoelectric polarization under an external mechanical force have emerged as an effective platform for cancer therapy. In this study, piezoelectric 2D WS₂ nanosheets are functionalized with mitochondria-targeting triphenylphosphonium (TPP) for ultrasound (US)-triggered, mitochondria-targeted piezodynamic cancer therapy. In addition, a glycolysis inhibitor (FX11) that can inhibit cellular energy metabolism is loaded into TPP- and poly(ethylene glycol) (PEG)-conjugated WS₂ nanosheet (TPEG-WS₂ ) to potentiate its therapeutic efficacy. Upon US irradiation, the sono-excited electrons and holes generated in the WS₂ are efficiently separated by piezoelectric polarization, which subsequently promotes the production of ROS. FX11-loaded TPEG-WS₂ (FX11@TPEG-WS₂ ) selectively accumulates in the mitochondria of human breast cancer cells. In addition, FX11@TPEG-WS₂ effectively inhibits the production of adenosine triphosphate . Thus, FX11@TPEG-WS₂ exhibits outstanding anticancer effects under US irradiation. An in vivo study using tumor-xenograft mice demonstrates that FX11@TPEG-WS₂ effectively accumulated in the tumors. Its tumor accumulation is visualized using in vivo computed tomography . Notably, FX11@TPEG-WS₂ with US irradiation remarkably suppresses the tumor growth of mice without systemic toxicity. This study demonstrates that the combination of piezodynamic therapy and energy metabolism-targeted chemotherapy using mitochondria-targeting 2D WS₂ is a novel strategy for the selective and effective treatment of tumors.

Novel aggregation-induced emission-photosensitizers with built-in capability of mitochondria targeting and glutathione depletion for efficient photodynamic therapy

Owing to its non-invasive feature and excellent therapeutic effect, photodynamic therapy has received considerable interest in cancer therapy. However, the therapeutic efficacy of photodynamic therapy is limited by some intrinsic drawbacks of photosensitizers such as aggregation-caused quenching and non-specificity towards cellular organelles. Moreover, the overexpressed glutathione in tumour cells which exhibits a potent scavenging effect on reactive oxygen species generated during the photodynamic therapy process also reduces the efficacy of photodynamic therapy. Therefore, the synthesis of aggregation-induced emission based photosensitizers with cellular organelle targeting and glutathione-depletion capability is highly desirable in photodynamic therapy. Here, two new aggregation-induced emission based photosensitizers namely tetraphenylethylene-1-phenyvinyl-pyridine-phenylboronic acid (TPEPy-BA) and tetraphenylethylene-1-phenyvinyl-pyridine-phenylboronic acid pinacol ester (TPEPy-BE) were synthesized which easily aggregated under aqueous conditions and showed bright emission in the near infra-red region. Furthermore, these photosensitizers were encapsulated into an amphiphilic block copolymer (DSPE-PEG) to improve the aqueous stability and cellular internalization of photosensitizers. The developed photosensitizer nanoparticles showed high reactive oxygen species generation efficacy, mitochondria-targeting and glutathione-depletion capability. The results showed that tetraphenylethylene-1-phenyvinyl-pyridine-phenylboronic acid pinacol ester nanoparticles exhibited a highly efficient photodynamic ablation of MCF-7 cells compared to tetraphenylethylene-1-phenyvinyl-pyridine-phenylboronic acid nanoparticles, upon white light irradiation, due to its high intracellular reactive oxygen species generation efficiency and mitochondria-dysfunction ability. Moreover, tetraphenylethylene-1-phenyvinyl-pyridine-phenylboronic acid pinacol ester nanoparticles produced a glutathione-depleting adjuvant, quinone methide, which greatly reduced the glutathione level in cancer cells, thus enhancing the efficacy of photodynamic therapy. This study provides a new strategy for the synthesis of aggregation-induced emission based photosensitizers with combined mitochondria-targeting and glutathione-depletion capability for efficacious photodynamic therapy.

Intraosseous administration into the skull: Potential blood-brain barrier bypassing route for brain drug delivery

Progress in treating central nervous system (CNS) disorders is retarded owing to a limited understanding of brain disease pathology. Additionally, the blood-brain barrier (BBB) limits molecular entry into the brain. Many approaches for brain drug delivery to overcome the BBB, such as BBB permeability enhancement, transient BBB disruption, and direct surgical administration have been explored with limited success. Recent research has shown that direct vascular channels exist between the skull bone marrow and the meninges, allowing myeloid and lymphoid cells to migrate. We hypothesized that these direct channels may also allow brain drug delivery from the skull bone marrow to the brain. In this study, for the first time we propose intraosseous administration of drugs into the skull (intracalvariosseous [ICO]) as a novel approach for brain drug delivery via BBB bypassing routes. We tested the feasibility of the approach by applying nine representative compounds over thinned mouse skulls to simulate ICO and measuring the compound entry level in the brain compared to that after systemic administration. Surprisingly, we found that the skull is not completely impermeable to drug penetration into the brain and the tested compounds reached the brain tissue several tens-to-hundred times higher by ICO than systemic application. These findings suggest a role for the BBB bypassing route from skull to brain, apart from the systemic route, in the drug entry into the brain after ICO. This approach should be applicable to other CNS drugs and even BBB impermeable drugs. Overall ICO provides an innovative and advantageous pathway for effective treatment of brain diseases.

Folic Acid Functionalized Diallyl Trisulfide-Solid Lipid Nanoparticles for Targeting Triple Negative Breast Cancer

DATS (diallyl trisulfide), an anti-oxidant and cytotoxic chemical derived from the plant garlic, has been found to have potential therapeutic activity against triple-negative breast cancer (TNBC). Its hydrophobicity, short half-life, lack of target selectivity, and limited bioavailability at the tumor site limit its efficacy in treating TNBC. Overexpression of the Folate receptor on the surface of TNBC is a well-known target receptor for overcoming off-targeting, and lipid nanoparticles solve the limitations of limited bioavailability and short half-life. In order to overcome these constraints, we developed folic acid (FA)-conjugated DATS-SLNs in this research. The design of experiment (DoE) method was employed to optimize the FA-DATS-SLNs' nanoformulation, which resulted in a particle size of 168.2 ± 3.78 nm and a DATS entrapment of 71.91 ± 6.27%. The similarity index between MCF-7 and MDA-MB-231 cell lines demonstrates that FA-DATS-SLNs are more therapeutically efficacious in the treatment of aggravating TNBC. Higher cellular internalization and efficient Bcl2 protein downregulation support the hypothesis that functionalization of the FA on the surface of DATS-SLNs improves anticancer efficacy when compared with DATS and DATS-SLNs. FA-functionalized DATS-SLNs have demonstrated to be a promising therapeutic strategy for TNBC management.

Mitochondria-targeting sonosensitizer-loaded extracellular vesicles for chemo-sonodynamic therapy

Sonodynamic therapy (SDT) has emerged as an effective therapeutic modality as it employs ultrasound (US) to eradicate deep-seated tumors noninvasively. However, the therapeutic efficacy of SDT in clinical settings remains limited owing to the low aqueous stability and poor pharmacokinetic properties of sonosensitizers. In this study, extracellular vesicles (EVs), which have low systemic toxicity, were used as clinically available nanocarriers to effectively transfer a sonosensitizer to cancer cells. Chlorin e6 (Ce6), a sonosensitizer, was conjugated to a mitochondria-targeting triphenylphosphonium (TPP) moiety and loaded into EVs to enhance the efficacy of SDT, because mitochondria are critical subcellular organelles that regulate cell survival and death. Additionally, piperlongumine (PL), a pro-oxidant and cancer-specific chemotherapeutic agent, was co-encapsulated into EVs to achieve efficient and selective anticancer activity. The EVs substantially amplified the cellular internalization of TPP-conjugated Ce6 (TPP-Ce6), resulting in the enhanced generation of intracellular reactive oxygen species (ROS) in MCF-7 human breast cancer cells upon US exposure. Importantly, EVs encapsulating TPP-Ce6 effectively destroyed the mitochondria under irradiation with US, leading to efficient anticancer activity. The co-encapsulation of pro-oxidant PL into EVs significantly enhanced the SDT efficacy in MCF-7 cells through the excessive generation of ROS. Moreover, the EV co-encapsulating TPP-Ce6 and PL [EV(TPP-Ce6/PL)] exhibited cancer-specific cell death owing to the cancer-selective apoptosis triggered by PL. In vivo study using MCF-7 tumor-xenograft mice revealed that EV(TPP-Ce6/PL) effectively accumulated in tumors after intravenous injection. Notably, treatment with EV(TPP-Ce6/PL) and US inhibited tumor growth significantly without causing systemic toxicity. This study demonstrated the feasibility of using EV(TPP-Ce6/PL) for biocompatible and cancer-specific chemo-SDT.

Why mRNA-ionizable LNPs formulations are so short-lived: causes and way-out

INTRODUCTION

Messenger ribonucleic acid (mRNA) and small interfering RNA (siRNA) are biological molecules that can be heated, frozen, lyophilized, precipitated, or re-suspended without degradation. Currently, ionizable lipid nanoparticles (LNPs) are a promising approach for mRNA therapy. However, the long-term shelf-life stability of mRNA-ionizable LNPs is one of the open questions about their use and safety. At an acidic pH, ionizable lipids shield anionic mRNA. However, the stability of mRNA under storage conditions remains a mystery. Moreover, ionizable LNPs excipients also cause instability during long-term storage.

AREA COVERED

This paper aims to illustrate why mRNA-ionizable LNPs have such a limited storage half-life. For the first time, we compile the tentative reasons for the short half-life and ultra-cold storage of mRNA-LNPs in the context of formulation excipients. The article also provided possible ways of prolonging the lifespan of mRNA-ionizable LNPs during long storage.

EXPERT OPINION

mRNA-ionizable LNPs are the future of genetic medicine. Current limitations of the formulation can be overcome by an advanced drying process or a whole new hybrid formulation strategy to extend the shelf life of mRNA-ionizable LNPs. A breakthrough technology may open up new research directions for producing thermostable and safe mRNA-ionizable LNPs at room temperature.

A tale of nucleic acid-ionizable lipid nanoparticles: Design and manufacturing technology and advancement

INTRODUCTION

Ionizable lipid nanoparticles (LNPs) have been proven to have high encapsulation, cellular uptake, and effective endosomal escape and are therefore promising for nucleic acid delivery. The combination of ionizable lipids, helper lipids, cholesterol, and PEG lipids advances nucleic acid-ionizable LNPs and distinguishes them from liposomes, SLNs, NLCs, and other lipid particles. Solvent injection and microfluidics technology are the primary manufacturing techniques for commercialized ionizable LNPs. Microfluidics technology limitations restrict the rapid industrial scale-up and therapeutic effectiveness of ionized LNPs. Alternative manufacturing technologies and target-specific lipids are urgently needed.

AREA COVERED

This article provides an in-depth update on the lipid compositions, clinical trials, and manufacturing technologies for nucleic acid-ionizable LNPs. For the first time, we updated the distinction between ionizable LNPs and other lipid particles. We also proposed an alternate thermocycling technology for high industrial scale-up and the stability of nucleic acid-ionizing LNPs.

EXPERT OPINION

Nucleic acid-ionizable LNPs have a promising future for delivering nucleic acids in a target-specific manner. Though ionizing LNPs are in their early stages, they face several challenges, including only hepatic delivery, a short shelf life, and ultra-cold storage. In our opinion, ligand-based, target-specific synthesized novel lipids and advanced manufacturing technologies can easily overcome the restrictions and open up a new approach for improved therapeutic efficacy for chronic disorders.

Single pot organic solvent-free thermocycling technology for siRNA-ionizable LNPs: a proof-of-concept approach for alternative to microfluidics

Ionizable LNPs are the latest trend in nucleic acid delivery. Microfluidics technology has recently gained interest owing to its rapid mixing, production of nucleic acid-ionizable LNPs, and stability of nucleic acid inside the body. Industrial scale-up, nucleic acid-lipid long-term storage instability, and high production costs prompted scientists to seek alternate solutions to replace microfluidic technology. We proposed a single-pot, organic solvent-free thermocycling technology to efficiently and economically overcome most of the limitations of microfluidic technology. New thermocycling technology needs optimization of process parameters such as sonication duration, cooling–heating cycle, number of thermal cycles, and lipid:aqueous phase ratio to formulate precisely sized particles, effective nucleic acid encapsulation, and better shelf-life stability. Our research led to the formulation of siRNA-ionizable LNPs with particle sizes of 104.2 ± 34.7 nm and PDI 0.111 ± 0.109, with 83.3 ± 4.1% siRNA encapsulation. Thermocycling siRNA-ionizable LNPs had comparable morphological structures with commercialized microfluidics ionizable LNPs imaged by TEM and cryo-TEM. When compared to microfluidics ionizable LNPs, thermocycling siRNA-ionizable LNPs had a longer shelf life at 4°C. Our thermocycling technology showed an effective alternative to microfluidics technology in the production of nucleic acid–ionizable LNPs to meet global demand.

Thermocycling technology is a low-energy, low-temperature, self-assembling cooling–heating process in which lipid droplets spontaneously break apart into much smaller droplets to form siRNA-ionizable LNPs.

The new technology is an alternative to multistep, costly, and complex microfluidics technology for the formulation and bulk up of siRNA-ionizable LNPs economically.

Thermocycling siRNA-ionizable LNPs formulation focused on optimizing process parameters such as thermal cycle rate, number of thermal cycles, and lipid:aqueous phase ratio.

The thermocycling technology is able to overcome the limitations of the storage stability limitations of commercialized ionizable LNPs.

Extracellular vesicles with high dual drug loading for safe and efficient combination chemo-phototherapy

Extracellular vesicles (EVs) have emerged as biocompatible nanocarriers for efficient delivery of various therapeutic agents, with intrinsic long-term blood circulatory capability and low immunogenicity. Here, indocyanine green (ICG)- and paclitaxel (PTX)-loaded EVs [EV(ICG/PTX)] were developed as a biocompatible nanoplatform for safe and efficient cancer treatment through near-infrared (NIR) light-triggered combination chemo/photothermal/photodynamic therapy. High dual drug encapsulation in EVs was achieved for both the hydrophilic ICG and hydrophobic PTX by simple incubation. The EVs substantially improved the photostability and cellular internalization of ICG, thereby augmenting the photothermal effects and reactive oxygen species production in breast cancer cells upon NIR light irradiation. Hence, ICG-loaded EVs activated by NIR light irradiation showed greater cytotoxic effects than free ICG. EV(ICG/PTX) showed the highest anticancer activity owing to the simultaneous chemo/photothermal/photodynamic therapy when compared with EV(ICG) and free ICG. In vivo study revealed that EV(ICG/PTX) had higher accumulation in tumors and improved pharmacokinetics compared to free ICG and PTX. In addition, a single intravenous administration of EV(ICG/PTX) exhibited a considerable inhibition of tumor proliferation with negligible systemic toxicity. Thus, this study demonstrates the potential of EV(ICG/PTX) for clinical translation of combination chemo-phototherapy.

Engineered extracellular vesicle-based sonotheranostics for dual stimuli-sensitive drug release and photoacoustic imaging-guided chemo-sonodynamic cancer therapy

Sonodynamic therapy has shown promise as an effective alternative to conventional photodynamic therapy owing to its ability to treat deep-seated tumors. However, the development of stimuli-responsive sonosensitizers with high biocompatibility faces a significant challenge.

Methods: In this study, we developed dual stimuli-responsive sonosensitizers with desirable biosafety using extracellular vesicles (EVs), a class of naturally occurring nanoparticles. Indocyanine green (ICG), which functions as both a sonosensitizer and photoacoustic (PA) imaging agent, was loaded into EVs, together with paclitaxel (PTX) and sodium bicarbonate (SBC), to achieve pH-responsive PA imaging-guided chemo-sonodynamic combination therapy.

Results: The EVs significantly improved the cellular uptake of ICG, thus triggering enhanced sonodynamic effects in breast cancer cells. SBC-, ICG-, and PTX-loaded EV [SBC-EV(ICG/PTX)] efficiently released the PTX in response to acidic pH in the endo/lysosomes because CO₂ bubbles generated from the SBC caused the EV membranes to burst. The drug release was further facilitated by ultrasound (US) treatment, demonstrating dual pH/US-responsive drug release. The ICG- and PTX-loaded EVs exhibited efficient anticancer activity against breast tumor cells owing to the combination of chemo-sonodynamic therapy. High-resolution PA imaging visualized the preferential tumor accumulation of SBC-EV(ICG/PTX) in tumor-bearing mice. Notably, a single intravenous injection of SBC-EV(ICG/PTX) with US irradiation significantly suppressed tumor growth in mice without systemic toxicity.

Conclusions: Our findings demonstrate that dual stimuli-responsive SBC-EV(ICG/PTX) are promising sonotheranostic nanoplatforms for safe and efficient chemo-sonodynamic combination cancer therapy and photoacoustic imaging.

Temperature and pH-responsive in situ hydrogels of gelatin derivatives to prevent the reoccurrence of brain tumor

Glioblastoma multiforme (GBM) is a grade IV malignant brain tumor with a median survival time of approximately 12-16 months. Because of its highly aggressive and heterogeneous nature it is very difficult to remove by surgical resection. Herein we have reported dual stimuli-responsive and biodegradable in situ hydrogels of oligosulfamethazine-grafted gelatin and loaded with anticancer drug paclitaxel (PTX) for preventing the progress of Glioblastoma. The oligosulfamethazine (OSM) introduced to the gelatin backbone for the formation of definite and stable in situ hydrogel. The hydrogels transformed from a sol to a gel state upon changes in stimuli. pH and temperature and retained a distinct shape after subcutaneous administration in BALB/c mice. The viscosity of the sol state hydrogels was tuned by varying the feed molar ratio between gelatin and OSM. The porosity of the hydrogels was confirmed to be lower in higher degree OSM by SEM. Sustained release of PTX from hydrogels in physiological environments (pH 7.4) was further retarded up to 63% in 9th days in tumor environments (pH 6.5). While the empty hydrogels were non-toxic in cultured cells, the hydrogels loaded with PTX showed antitumor efficacy in orthotopic-GBM xenograft mice. Collectively, the gelatin-OSM formed porous hydrogels and released the cargo in a sustained manner in tumor environments efficiently suppressing the progress of GBM. Thus, gelatin-OSM hydrogels are a potential candidate for the direct delivery of therapeutics to the local areas in brain diseases.

Safe and Targeted Sonodynamic Cancer Therapy Using Biocompatible Exosome-Based Nanosonosensitizers

Sonodynamic therapy (SDT), wherein sonosensitizers irradiated with ultrasound (US) produce cytotoxic reactive oxygen species (ROS), has garnered great attention as a promising alternative to photodynamic therapy owing to the significantly increased depth of tissue penetration. The development of nanocarriers that can selectively deposit sonosensitizers into tumor tissues without systemic toxicity is crucial to facilitate the translation of SDT to clinical use. In this study, exosomes, a class of naturally occurring nanoparticles, were utilized as nanocarriers for safe and cancer-targeted delivery of a sonosensitizer, indocyanine green (ICG). The exosomes were surface-engineered with an active cancer-targeting ligand, folic acid (FA), to increase the cancer specificity of the ICG-loaded exosomes (ExoICG). The FA-conjugated, ICG-loaded exosomes (FA-ExoICG) greatly improved aqueous stability and cellular uptake of ICG, resulting in significantly increased ROS generation in breast cancer cells. As a result, the FA-ExoICG demonstrated greater sonotoxicity against cancer cells than ExoICG and free ICG. The in vivo study revealed that compared to ExoICG, more FA-ExoICG accumulated in tumors, and their pharmacokinetic properties were superior. Notably, tumor growth in mice was significantly suppressed, without systemic toxicity, by a single intravenous injection of the FA-ExoICG and subsequent US irradiation. Therefore, this study demonstrated that active cancer-targeted FA-ExoICG could serve as effective nanosonosensitizers for safe and targeted cancer treatment.

Lipid Nanoparticles Improve the Uptake of α-Asarone Into the Brain Parenchyma: Formulation, Characterization, In Vivo Pharmacokinetics, and Brain Delivery

Treatment of brain-related diseases is one of the most strenuous challenges in drug delivery research due to numerous hurdles, including poor blood-brain barrier penetration, lack of specificity, and severe systemic toxicities. Our research primarily focuses on the delivery of natural therapeutic compound, α-asarone, for the treatment of brain-related diseases. However, α-asarone has poor aqueous solubility, bioavailability, and stability, all of which are critical issues that need to be addressed. This study aims at formulating a lipid nanoparticulate system of α-asarone (A-LNPs) that could be used as a brain drug delivery system. The physicochemical, solid-state properties, stability, and in vitro and in vivo studies of the A-LNPs were characterized. The release of α-asarone from the A-LNPs was prolonged and sustained. After intravenous administration of A-LNPs or free α-asarone, significantly higher levels of α-asarone from the A-LNPs were detected in murine plasma and brain parenchyma fractions, confirming the ability of A-LNPs to not only maintain a therapeutic concentration of α-asarone in the plasma, but also transport α-asarone across the blood-brain barrier. These findings confirm that lipid nanoparticulate systems enable penetration of natural therapeutic compound α-asarone through the blood-brain barrier and may be a candidate for the treatment of brain-related diseases.

Small molecule tyrosine kinase inhibitors in glioblastoma

Glioblastoma (GBM) is the most common malignant primary brain tumor, with poor survival despite treatment with surgery, radiotherapy, and chemotherapy with temozolomide. Little progress has been made over the last two decades, and there remain unmet medical needs. Approximately 45% of patients with GBM carry EGFR mutations, and 13% of them possess altered PDGFR genes. Moreover, VEGF/VEGFR mutations are also observed in the patient population. Tyrosine kinase inhibitors (TKIs) are emerging cancer therapy drugs that inhibit signal transduction cascades affecting cell proliferation, migration, and angiogenesis. Indications for small molecule TKIs have been successfully expanded to multiple types of cancer; however, none of the TKIs have been approved for patients with GBM. In this review, we summarize clinical trials of small molecule TKIs in patients with GBM and plausible hypotheses for negative clinical study results. We also discuss the potential TKI candidates that presented significant preclinical outcomes in patients with GBM.

Dual-selective photodynamic therapy with a mitochondria-targeted photosensitizer and fiber optic cannula for malignant brain tumors

Among brain tumors, glioblastoma multiforme (GBM) is the most common and aggressive form (WHO grade IV) with a median survival of only 14.6 months in adults. Photodynamic therapy (PDT) is a combination of a photosensitizer (PS), light and molecular oxygen, and considered a promising treatment for GBM. Therapeutic outcomes of PDT rely on ROS generation in a tumor microenvironment, which can be controlled with dual selectivity by localization of the photosensitizer and confinement of light to the targeted tumor microenvironment. We previously demonstrated the photodynamic anticancer efficacy of mitochondrial-targeted photosensitizer-loaded albumin nanoparticles (PS@chol-BSA NPs). In this study, the photodynamic therapeutic effect of PS@chol-BSA NPs was further enhanced by confinement of light using a fiber optic cannula in orthotopic GBM-xenografted mice. In vitro cellular uptake and phototoxicity of PS@chol-BSA NPs were evaluated in brain tumor (U87MG) and endothelial (bEnd.3) cells. In vivo biodistribution was determined by an in vivo imaging system (IVIS) and the photodynamic efficacy was evaluated with confined laser irradiation. PS@chol-BSA NPs showed higher cellular uptake and phototoxicity in U87MG cells than in bEnd.3 cells. PS@chol-BSA NPs showed a brain tumor accumulation of 0.2%ID within 2 h and remain in the brain tumor for 22 h. When compared to the control group, there was remarkable suppression in tumor growth by laser irradiation with and without the fiber optic cannula at a dose of 1 mg kg^-1, in which significant tumor suppression up to 40% was observed with confined laser irradiation. Together, dual-selective photodynamic therapy with a mitochondria-targeted photosensitizer and fiber optic cannula provides a promising therapeutic strategy for malignant brain tumors.

pH-sensitive PEGylation of RIPL peptide-conjugated nanostructured lipid carriers: design and in vitro evaluation

BACKGROUND

RIPL peptide (IPLVVPLRRRRRRRRC)-conjugated nanostructured lipid carriers (RIPL-NLCs) can facilitate selective drug delivery to hepsin (Hpn)-expressing cancer cells, but they exhibit low stability in the blood. Generally, biocompatible and nontoxic poly(ethylene glycol) surface modification (PEGylation) can enhance NLC stability, although this may impair drug delivery and NLC clearance. To attain RIPL-NLC steric stabilization without impairing function, pH-sensitive cleavable PEG (cPEG) was grafted onto RIPL-NLCs (cPEG-RIPL-NLCs).

METHODS

Various types of NLC formulations including RIPL-NLCs, PEG-RIPL-NLCs, and cPEG-RIPL-NLCs were prepared using the solvent emulsification-evaporation method and characterized for particle size, zeta potential (ZP), and cytotoxicity. The steric stabilization effect was evaluated by plasma protein adsorption and phagocytosis inhibition studies. pH-sensitive cleavage was investigated using the dialysis method under different pH conditions. Employing a fluorescent probe (1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate [DiI]), in vitro drug delivery capacity of the cPEG-RIPL-NLCs under different pH conditions was also performed on Hpn-expressing SKOV3 cells and 3D-tumor spheroids.

RESULTS

All prepared NLCs showed homogenous dispersion (<220 nm in size) with a negative ZP (-18 to -22 mV), except for positively charged RIPL-NLCs (~10 mV), revealing no significant cytotoxicity in either SKOV3 or RAW 264.7 cell lines. cPEG-RIPL-NLC protein adsorption was 1.75-fold less than that of RIPL-NLCs, and PEGylation significantly reduced the macrophage uptake. PEG detachment from the cPEG-RIPL-NLCs was pH-sensitive and time dependent. At 2 hours incubation, cPEG-RIPL-NLCs and PEG-RIPL-NLCs exhibited comparable cellular uptake at pH 7.4, whereas cPEG-RIPL-NLC uptake was increased over 2-fold at pH 6.5. 3D-spheroid penetration also demonstrated pH-sensitivity: at pH 7.4, cPEG-RIPL-NLCs could not penetrate deep into the spheroid core region during 2 hours, whereas at pH 6.5, high fluorescence intensity in the core region was observed for both cPEG-RIPL-NLC-and RIPL-NLC-treated groups.

CONCLUSION

cPEG-RIPL-NLCs are good candidates for Hpn-selective drug targeting in conjunction with pH-responsive PEG cleavage.

Docetaxel-Loaded Hyaluronic Acid-Cathepsin B-Cleavable-Peptide-Gold Nanoparticles for the Treatment of Cancer

Gold nanoparticles are commonly used for medical applications such as drug delivery and as therapeutic and diagnostic materials because of their unique properties. In this study, we prepared docetaxel (DTX)-loaded hyaluronic acid-cleavable-peptide-gold nanoparticles for the treatment of cancer by selectively delivering DTX into the tumor and, thus, enhancing the therapeutic effect of DTX; further, we determined synergistic effects of the nanoparticles using laser treatment. The DTX-loaded hyaluronic acid-cleavable-peptide-gold nanoparticles prepared in this study had an average size of 75 nm and negative surface charge. The nanoparticles revealed greater cytotoxicity and higher tumor suppression efficacy in tumor models than free DTX under near-infrared laser irradiation. Therefore, the nanoparticle formulation prepared in this study could be utilized for targeted drug delivery and in combination with other cancer therapies.

Investigation on the effect of nanoparticle size on the blood-brain tumour barrier permeability by in situ perfusion via internal carotid artery in mice

The blood-brain barrier (BBB) is a limiting factor in nanoparticle drug delivery to the brain, and various attempts have been made to overcome it for efficient drug delivery. Nowadays, it was considered as further issue for brain-drug delivery that the nanoparticle delivered to brain through the BBB reach cancer cells in tumour tissue. In this study, we investigated the effect of nanoparticle size on blood-brain tumour barrier (BBTB) permeation of fluorescence-labelled gold nanoparticles (AuNPs) in a mouse model of orthotopic glioblastoma multiforme (GBM), established by intracranial implantation of luciferase-expressing human glioblastoma U87MG cells. AuNPs sized 10, 50, and 100 nm were perfused into the GBM mice via internal carotid artery (ICA) for 5 min. Immediately after perfusion, the brains were fixed and prepared for LSCM observation. The AuNPs distribution in the normal and tumorous brain tissues was analysed qualitatively and quantitatively. Higher distribution of AuNPs was observed in the tumorous tissue than in the normal tissue. Furthermore, the smallest nanoparticle, 10 nm AuNPs, was widely distributed in the brain tumour tissue, whereas the 50 and 100 nm AuNPs were located near the blood vessels. Therefore, nanoparticle size affected the permeation of nanoparticles from the blood into brain tumour tissue.

Recent developments in solid lipid nanoparticle and surface-modified solid lipid nanoparticle delivery systems for oral delivery of phyto-bioactive compounds in various chronic diseases

Solid lipid nanoparticle (SLN) delivery systems have a wide applicability in the delivery of phyto-bioactive compounds to treat various chronic diseases, including diabetes, cancer, obesity and neurodegenerative diseases. The multiple benefits of SLN delivery include improved stability, smaller particle size, leaching prevention and enhanced lymphatic uptake of the bioactive compounds through oral delivery. However, the burst release makes the SLN delivery systems inadequate for the oral delivery of various phyto-bioactive compounds that can treat such chronic diseases. Recently, the surface-modified SLN (SMSLN) was observed to overcome this limitation for oral delivery of phyto-bioactive compounds, and there is growing evidence of an enhanced uptake of curcumin delivered orally via SMSLNs in the brain. This review focuses on different SLN and SMSLN systems that are useful for oral delivery of phyto-bioactive compounds to treat various chronic diseases.

Triphenylphosphine-docetaxel conjugate-incorporated albumin nanoparticles for cancer treatment

Aim: The objective of this study was to develop a mitochondria-targeted anticancer drug, docetaxel (DTX), for chemotherapy. Materials & methods: The DTX was conjugated to 4-carboxybutyl triphenylphosphonium (TPP) to enhance mitochondrial targeting, and the TPP–DTX conjugate was further loaded into folate-cholesteryl albumin (FA-chol-BSA) nanoparticles (NPs) to improve its biocompatibility. Results & conclusion: In vitro studies showed that TPP–DTX and its NP primarily accumulated in the mitochondria; generated high reactive oxygen species, leading to mitochondrial disruption and cell apoptosis; and had a higher cytotoxicity against cancer cells. In vivo antitumor studies indicated that the NP significantly suppressed tumor growth compared with free drugs in xenograft tumor-bearing mice. Our results demonstrated that TPP–DTX@FA-chol-BSA NPs could be a promising mitochondria-targeted anticancer prodrug for chemotherapy.

Self-Assembling Lipid-Peptide Hybrid Nanoparticles of Phospholipid-Nonaarginine Conjugates for Enhanced Delivery of Nucleic Acid Therapeutics

Despite potential applications of nucleic acid therapeutics, the lack of effective delivery systems hinders their clinical application. To overcome the barriers to nucleic acid delivery, we previously reported nanoparticles using phospholipid-polyethylenimine conjugates. However, toxicity of polyethylenimine remains as a problematic issue. Herein, we proposed to substitute the polyethylenimine with arginine-rich peptide to obtain a less-toxic carrier system. Nonaarginine was conjugated to the distal end of phospholipid hydrocarbon chains leading to phospholipid-nonaarginine conjugates (PL9R) and then lipid-peptide hybrid nanoparticles carrying oligonucleotide therapeutics (hNP) were constructed by self-assembly process. The hNP were further modified with cell penetrating Tat peptide (T-hNP) to enhance cellular uptake. The PL9R was less cytotoxic, and the hNP showed high loading capacity and colloidal stability. The T-hNP showed higher cellular uptake and transfection efficiency and effective accumulation to tumor tissue and silencing effect in tumor bearing mice. Altogether, T-hNP could provide a promising nanocarrier for nucleic acid therapeutics.

Wasabia japonica is a potential functional food to prevent colitis via inhibiting the NF-κB signaling pathway

Inflammatory bowel diseases (IBDs), including Crohn's disease (CD) and ulcerative colitis (UC), are prevalent and debilitating health problems worldwide. Many types of drugs are used to treat IBDs, but they exhibit adverse effects such as vomiting, nausea, abdominal pain, diarrhea, etc. In order to overcome the limitations of current therapeutic drugs, scientists have searched for functional foods from natural resources. In this study, we investigated the anti-colitic effects of Wasabia japonica extract in a DSS-induced colitis model. Wasabi japonica is a plant of the Brassicaceae family that has recently been reported to exhibit properties of detoxification, anti-inflammation, and induction of apoptosis in cancer cells. In this study, we generated wasabi ethanol extract (WK) and assessed its anti-colitic effect. In addition, in order to improve delivery of the extract to the colon, WK was coated with 5% Eudragit S100 (WKE), after which the anti-colitic effects of WKE were assessed. In conclusion, WK prevented development of colitis through inhibition of the NF-kB signaling pathway and recovery of epithelial tight junctions. In addition, the anti-colitic effect of WK was enhanced by improving its delivery to the colon by coating the WK with Eudragit S100. Therefore, we suggest that wasabi can be used as a new functional food to prevent IBDs due to its anti-colitic effect.

Mitochondrial-targeted photosensitizer-loaded folate-albumin nanoparticle for photodynamic therapy of cancer

The objective of this study was to develop a mitochondria-targeted photosensitizer (PS) for photodynamic therapy (PDT). Herein, a porphyrin-derivative photosensitizer, pheophorbide-a (PheoA), was conjugated to carboxybutyltriphenylphosphonium (TPP) via a carbodiimide linkage to enhance mitochondrial targeting and TPP-PheoA conjugate was further loaded into folate-cholesteryl albumin (FA-chol-BSA) nanoparticles (NPs) to improve its biocompatibility. Cellular uptake results showed that TPP-PheoA and TPP-PheoA@FA-chol-BSA NPs were readily taken up by B16F10 and HeLa cells. Further in vitro studies exhibited that TPP-PheoA and its nanoparticle primarily accumulate in the mitochondria, greatly generate ROS, lead mitochondrial disruption and cell apoptosis, and have higher phototoxicity against cancer cells. In vivo bioimaging and the in vivo antitumor studies indicated that TPP-PheoA@FA-chol-BSA NP greatly accumulated in the tumor area and significantly suppress the tumor growth as compared to PheoA@FA-chol-BSA NP in tumor-bearing mice. Taken together, TPP-PheoA@FA-chol-BSA NP could be a promising mitochondria-targeted PS for image-guided PDT.

Graphene oxide-incorporated pH-responsive folate-albumin-photosensitizer nanocomplex as image-guided dual therapeutics

The objective of this study was to develop an active-targeted, pH-responsive albumin-photosensitizer-incorporated graphene oxide nanocomplex as an image-guided theranostic agent for dual therapies. Herein, bovine serum albumin (BSA)-cis-aconityl pheophorbide-a (c-PheoA) conjugate was complexed with graphene oxide (GO) at ratios of 1:1, 1:0.5, and 1:0.1 with the mean hydrodynamic diameter of the resulting complex being 100-200nm. Further, with the 1:0.5 ratio, we developed a folate-BSA-c-PheoA conjugate:GO complex incorporated free PheoA (PheoA+GO:FA-BSA-c-PheoA NC) with a mean hydrodynamic diameter of 182.0±33.2nm. The release study showed that the photosensitizer from the nanocomplex was released rapidly at pH5.5 compared to that at pH7.4 when incubated for 24h. Cellular uptake results showed that the PheoA+GO:FA-BSA-c-PheoA NCs was readily taken up by B16F10 and MCF7 cancer cells. In vitro phototoxicity results showed that PheoA+GO:FA-BSA-c-PheoA NC has a higher efficacy against cancer cells than free PheoA, thereby demonstrating the synergistic effect of PS and GO in response to a single laser of 670nm. In vivo and ex vivo bioimaging results showed that fluorescence signals of higher intensity were observed in the tumor area of mice treated with PheoA+GO:FA-BSA-c-PheoA NC than those in the tumor of mice treated with free PheoA, thereby suggesting that the targeted nanocomplex selectively accumulated in the tumor area compared to free PheoA. Through antitumor study, PheoA+GO:FA-BSA-c-PheoA NC showed a synergistic effect in tumor-bearing mice by a single 671nm laser treatment. These results demonstrate that our prepared PheoA+GO:FA-BSA-c-PheoA NC can be used as a theranostic agent in phototherapies and for the photodiagnosis of cancer.

Anti-Melanogenic Potentials of Nanoparticles from Calli of Resveratrol-Enriched Rice against UVB-Induced Hyperpigmentation in Guinea Pig Skin

We already reported that genetically engineered resveratrol-enriched rice (RR) showed to down-regulate skin melanogenesis. To be developed to increase the bioactivity of RR using calli from plants, RR was adopted for mass production using plant tissue culture technologies. In addition, high-pressure homogenization (HPH) was used to increase the biocompatibility and penetration of the calli from RR into the skin. We aimed to develop anti-melanogenic agents incorporating calli of RR (cRR) and nanoparticles by high-pressure homogenization, examining the synergistic effects on the inhibition of UVB-induced hyperpigmentation. Depigmentation was observed following topical application of micro-cRR, nano-calli of normal rice (cNR), and nano-cRR to ultraviolet B (UVB)-stimulated hyperpigmented guinea pig dorsal skin. Colorimetric analysis, tyrosinase immunostaining, and Fontana-Masson staining for UVB-promoted melanin were performed. Nano-cRR inhibited changes in the melanin color index caused by UVB-promoted hyperpigmentation, and demonstrated stronger anti-melanogenic potential than micro-cRR. In epidermal skin, nano-cRR repressed UVB-promoted melanin granules, thereby suppressing hyperpigmentation. The UVB-enhanced, highly expressed tyrosinase in the basal layer of the epidermis was inhibited by nano-cRR more prominently than by micro-cRR and nano-cNR. The anti-melanogenic potency of nano-cRR also depended on pH and particle size. Nano-cRR shows promising potential to regulate skin pigmentation following UVB exposure.

Improved oral delivery of resveratrol from N-trimethyl chitosan-g-palmitic acid surface-modified solid lipid nanoparticles

Despite the therapeutic effects of resveratrol, its clinical application is restricted by its poor oral bioavailability, low water solubility, and instability. Solid lipid nanoparticles (SLNs)-based drug delivery systems have been shown to provide excellent support for the delivery of hydrophobic drugs. The poor stability and burst release behavior in stomach acidic pH conditions of SLNs result in increased aggregation of the particles in the gastrointestinal environment, limiting the success of these particles as an oral delivery system for hydrophobic drugs. N-trimethyl chitosan (TMC) graft palmitic acid (PA) (TMC-g-PA) mucoadhesive copolymer was hypothesized to be a promising candidate for the surface modification of PA-decorated resveratrol-loaded SLNs to stabilize SLNs and circumvent all the above mentioned obstacles. TMC and TMC-g-PA copolymers were therefore synthesized and characterized by (1)H-nuclear magnetic resonance ((1)H NMR) and Fourier-transformed infra-red (FT-IR) spectroscopy. Resveratrol-loaded SLNs (SLRNs) that comprised Precirol ATO 5, PA, Gelucire 50/13, Tween 80, and resveratrol as well as TMC-g-PA SLRNs were formulated and characterized in terms of physicochemical properties, stability, cytotoxicity, and in vitro and in vivo effects. The in vitro release studies of TMC-g-PA SLRNs demonstrated negligible release of resveratrol in simulated gastric and sustained release in simulated intestinal conditions and the relative bioavailability of resveratrol was furthermore found to be 3.8-fold higher from TMC-g-PA SLRNs than that from resveratrol suspension. Overall, the findings reported here indicate that TMC-g-PA SLRNs represent a potential oral drug delivery system for resveratrol.

Spotlight on nano-theranostics in South Korea: applications in diagnostics and treatment of diseases

From the synergistic integration and the multidisciplinary strengths of the BioNano Sensor Research Center, Gachon Bionano Research Institute, and Lee Gil Ya Cancer and Diabetes Institute, researchers, students, and faculties at Gachon University in collaboration with other institutions in Korea, Australia, France, America, and Japan have come together to produce a special issue on the diverse applications of nano-theranostics in nanomedicine. This special issue will showcase new research conducted by various scientific groups in Gyonggi-do and Songdo/Incheon, South Korea. The objectives of this special issue are as follows: 1) to bring together and demonstrate some of the latest research results in the field, 2) to introduce new multifunctional nanomaterials and their applications in imaging and detection methods, and 3) to stimulate collaborative interdisciplinary research at both national and international levels in nanomedicine.

Lipid-coated gold nanocomposites for enhanced cancer therapy

The aim of the work reported here was to develop lipid-coated multifunctional nanocomposites composed of drugs and nanoparticles for use in cancer therapy. We incorporated thermosensitive phospholipids onto the surface of anisotropic gold nanoparticles (AuNPs) to further enhance drug delivery, with possible additional applications for in vivo imaging and photothermal cancer therapy. Lipid-coated nanohybrids loaded with the drug docetaxel (DTX) were prepared by a thin-film formation, hydration, and sonication method. Nanoparticles and their composites were characterized using particle-size analysis, zeta potential measurements, transmission electron microscopy, UV-visible spectroscopy, and reverse-phase high-performance liquid chromatography, demonstrating successful loading of DTX into the lipid bilayer on the surface of the gold nanoparticles. Initial in vitro studies using breast-cancer (MCF-7) and melanoma (B16F10) cell lines demonstrated that the drug-containing nanocomposites at equivalent drug concentrations caused significant cytotoxicity compared to free DTX. Differential flow cytometry analysis confirmed the improved cellular uptake of lipid-coated nanocomposites. Our preliminary results show that DTX-loaded anionic lipid-coated gold nanorod (AL_AuNR_DTX) and cationic lipid-coated gold nanoparticle (CL_AuNP_DTX) possess effective tumor cell-suppression abilities and can therefore be considered promising chemotherapeutic agents. Further evaluation of the therapeutic efficacy of these hybrid nanoparticles combined with external near-infrared photothermal treatment is warranted to assess their synergistic anticancer actions and potential bioimaging applications.

Long-circulating self-assembled cholesteryl albumin nanoparticles enhance tumor accumulation of hydrophobic anticancer drug

The objective of this study was to develop an albumin nanoparticle with improved stability and drug loading capacity. Generation of nanomaterials having physiologically stable and high potential for drug delivery is still challenging. Herein we synthesized cholesteryl albumin conjugate using N,N-disuccinimidyl carbonate coupling reagent and prepared paclitaxel-loaded cholesteryl albumin nanoparticle (PTX-Chol-BSA) by self-assembly with the mean hydrodynamic diameter of 147.6±1.6nm and with high loading capacity. PTX-Chol-BSA nanoparticle showed much higher colloidal stability than a simple complex of PTX and BSA (PTX-BSA) and sustained release profile. PTX-Chol-BSA nanoparticles exhibited greater cellular uptake and cytotoxicity in B16F10 and MCF-7 cancer cell lines, as compared with PTX in Cremophor EL/ethanol (PTX-Cre/EtOH) and PTX-BSA formulations. A pharmacokinetic study in tumor-bearing mice showed that the area under the concentration-time curve (AUC0-8 h) following the administration of PTX-Chol-BSA was 1.6-2-fold higher than those following the administration of PTX-Cre/EtOH and PTX-BSA. In addition, the tumor AUC0-8 h of PTX-Chol-BSA was around 2-fold higher than that of PTX-BSA. Furthermore, in vivo antitumor efficacy results revealed that PTX-Chol-BSA nanoparticles have greater antitumor efficacy. In conclusion, we demonstrated the potential of PTX-Chol-BSA nanoparticles for anti-tumor chemotherapy, with enhanced in vitro and in vivo behaviors, as compared to PTX-BSA and PTX-Cre/EtOH.

Active-targeted pH-responsive albumin–photosensitizer conjugate nanoparticles as theranostic agents

The objective of this study was to develop an active-targeted, pH-responsive albumin–photosensitizer conjugate as a theranostic agent.

Folate-targeted liposome encapsulating chitosan/oligonucleotide polyplexes for tumor targeting

We previously reported that a liposome encapsulating polyethylenimine/oligonucleotides is suitable for in vivo delivery of nucleic acid therapeutics. However, toxicity of polyethylenimine is an obstacle in clinical application. To develop a liposome encapsulating polyplexes applicable to clinical use, we proposed to replace polyethylenimine with chitosan and thus constructed the liposome encapsulating low-molecular weight chitosan (LMWC)/oligonucleotide (ODN) polyplexes [LS(CO)]. ODN was completely complexed to LMWC at pH 5.5 and an N/P ratio 10 with a positive zeta potential of 19.81 ± 1.11. The positively charged polyplexes were encapsulated into anionic liposome by membrane extrusion. Folate-targeted liposome encapsulating LMWC/ODN complex [FLS(CO)] was prepared by adding folate-conjugated phospholipid. The resulting LS(CO) and FLS(CO) were characterized with respect to size distribution, zeta potential, and colloidal stability. The LS(CO) and FLS(CO) were also evaluated for in vitro cellular uptake and cytotoxicity. The LS(CO) and FLS(CO) showed a narrow size distribution with a mean diameter of about 130 nm and neutral zeta potentials and remained stable for 7 days in 0.15-M NaCl at room temperature. FLS(CO) showed higher cellular uptake than LS(CO) in B16F10 murine melanoma cells. Furthermore, LS(CO) showed less toxicity as compared to liposome encapsulating polyethylenimine/oligonucleotides, representing a biocompatible nanocarrier of oligonucleotide therapeutics.

A validated LC-MS/MS method for quantitative analysis of curcumin in mouse plasma and brain tissue and its application in pharmacokinetic and brain distribution studies

Curcumin is a well-known multitherapeutic agent widely employed in neurodegenerative disorders and cancer. A selective, fast, and sensitive method employing liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was developed and validated for the simultaneous determination of curcumin in mouse plasma and brain tissue, by using salbutamol as an internal standard. Triple quadrupole mass detection with multiple reaction monitoring (MRM) mode was used to monitor the ion transitions, m/z of 369>285 for curcumin, and m/z of 240>148 for salbutamol. The method was validated for recovery, accuracy, precision, linearity, and applicability. The lower limits of quantification (LLOQ) in both matrices were 2.5ng/mL. The inter-day and intra-day precisions and accuracy values were within the Food and Drug Administration (FDA) acceptance criteria, for both matrixes. The method was successfully applied in pharmacokinetics and brain distribution studies of curcumin after intravenous administration of free curcumin and curcumin-loaded solid lipid nanoparticles to mice. Furthermore, the application of this method along with serial blood sampling in mice has led to significant reduction in animal use and dosage and drastic improvement in speed, throughput, and quality of pharmacokinetic parameters.

Matrix metalloproteinase-8 plays a pivotal role in neuroinflammation by modulating TNF-α activation

Matrix metalloproteinases (MMPs) play important roles in normal brain development and synaptic plasticity, although aberrant expression of MMPs leads to brain damage, including blood-brain barrier disruption, inflammation, demyelination, and neuronal cell death. In this article, we report that MMP-8 is upregulated in LPS-stimulated BV2 microglial cells and primary cultured microglia, and treatment of MMP-8 inhibitor (M8I) or MMP-8 short hairpin RNA suppresses proinflammatory molecules, particularly TNF-α secretion. Subsequent experiments showed that MMP-8 exhibits TNF-α-converting enzyme (TACE) activity by cleaving the prodomain of TNF-α (A(74)/Q(75), A(76)/V(77) residues) and, furthermore, that M8I inhibits TACE activity more efficiently than TAPI-0, a general TACE inhibitor. Biochemical analysis of the underlying anti-inflammatory mechanisms of M8I revealed that it inhibits MAPK phosphorylation, NF-κB/AP-1 activity, and reactive oxygen species production. Further support for the proinflammatory role of microglial MMP-8 was obtained from an in vivo animal model of neuroinflammatory disorder. MMP-8 is upregulated in septic conditions, particularly in microglia. Administration of M8I or MMP-8 short hairpin RNA significantly inhibits microglial activation and expression/secretion of TNF-α in brain tissue, serum, and cerebrospinal fluid of LPS-induced septic mice. These results demonstrate that MMP-8 critically mediates microglial activation by modulating TNF-α activity, which may explain neuroinflammation in septic mouse brain.

Self-assembled polymeric nanoparticle of PEGylated chitosan-ceramide conjugate for systemic delivery of paclitaxel

Chitosan has been widely explored as one of the most favorable biomaterials for various pharmaceutical applications due to its biodegradability and biocompatibility. Here, we report novel PEGylated-chitosan-ceramide (PEG-CS-CE) that forms stable polymeric nanoparticles capable of functioning as efficient carriers of hydrophobic drug molecules. The chitosan-ceramide conjugate (CS-CE) was linked with amine-polyethyleneglycol (NH2-PEG2000) by using dicyclohexylcarbodiimide/N-hydroxysuccinimide (DCC-NHS) to obtain PEG-CS-CE that could exhibit steric stabilization in biological environments. The structure of the conjugate was determined by proton ((1)H) NMR and FT-IR spectrometry. Under suitable conditions, the PEG-CS-CE self-assembled to form colloidally stable nanoparticles with a mean diameter of ∼ 200 nm. Further, hydrophobic anti-tumor agent paclitaxel (PTX) was incorporated into the polymeric nanoparticle with 90% loading efficiency and 11.3% loading capacity via an emulsion-solvent evaporation method. The PTX-loaded PEG-CS-CE nanoparticle showed sustained release and exhibited higher cellular uptake and a comparable cytotoxic efficacy to that of free PTX on B16F10 melanoma and MCF-7 human breast adenocarcinoma cell lines. The empty nanoparticle showed no toxicity, indicating that the co-polymer is safe to use in drug delivery. The polymeric nanoparticle PEG-CS-CE developed by us represent promising nanocarriers of hydrophobic drug molecules.

Self-assembling micelle-like nanoparticles with detachable envelopes for enhanced delivery of nucleic acid therapeutics

In spite of the great potential of nucleic acids as therapeutic agents, the clinical application of nucleic acid therapeutics requires the development of effective systemic delivery strategies. In an effort to develop effective nucleic acid delivery systems suitable for clinical application, we previously reported a self-assembling micelle-like nanoparticle that was based on phospholipid-polyethylenimine conjugates, i.e., "micelle-like nanoparticles" (MNPs). In this study, we aimed to improve the system by enhancing the efficiency of intracellular delivery of the payload via pH-responsive detachment of the monolayer envelope and release of the nucleic acid therapeutics upon reaching the target tissues with an acidic pH, e.g., tumors. The acid-cleavable phospholipid-polyethylenimine conjugate was synthesized via hydrazone bond, and acid-cleavable MNPs were then prepared and characterized as before. We evaluated the acid-cleavable MNP construct for in vitro and in vivo nucleic acid delivery efficiency using cultured tumor cells and tumor-bearing mice. The acid-cleavable nanocarrier showed an enhanced cellular delivery at pH 6.5 as compared to pH 7.4, whereas the noncleavable nanocarrier did not show any differences. Tail vein injections also led to enhanced intracellular uptake of the acid-cleavable nanocarrier compared to the noncleavable nanocarrier into tumor cells of tumor-bearing mice although no significant difference was observed in total tumor accumulation.

Nanoparticle-mediated delivery of oligonucleotides to the blood-brain barrier: in vitro and in situ brain perfusion studies on the uptake mechanisms

Except for the few exceptions where topical administration is feasible, progress towards broad clinical application of nucleic acid therapeutics requires development of effective systemic delivery strategies. The central nervous system represents a particularly difficult organ for systemic delivery due to the blood-brain barrier. We previously reported a nanoparticulate delivery system for targeted brain delivery of oligonucleotides upon systemic administration, i.e. liposome-encapsulated polyethylenimine/oligonucleotides polyplexes. In this study, cellular uptake and intracellular trafficking of the nanoparticles were further investigated using in situ brain perfusion technique followed by colocalization and fluorescence resonance energy transfer techniques. The brain endothelial uptake and possibly parenchymal accumulation were readily visualized upon administration via internal carotid artery perfusion. The nanoparticles were colocalized with early-endosome antigen, which confirms the brain endothelial uptake through transferrin receptor-mediated endocytosis. Fluorescence resonance energy transfer analysis also suggested the nanoparticles entered the brain endothelial cells while maintaining their integrity. Together, the enhanced brain uptake, as claimed previously, of the antibody-targeted nanoparticles was clearly confirmed with more convincing evidences. In addition, the experimental techniques described here should be applicable to the studies involving nanoparticle-mediated brain delivery of nucleic acid therapeutics.

Anti-inflammatory effects of a methanol extract from Pulsatilla koreana in lipopolysaccharide-exposed rats

To investigate the therapeutic effect of a Korean herbal medicine Pulsatilla koreana as an anti-septic agent, anti-inflammatory effects of the herbal medicine were determined in lipopolysaccharide (LPS)-exposed rats. Treatment with a methanol extract from Pulsatilla koreana significantly inhibited LPS-induced inflammatory responses. Results from ELISA analysis showed that Pulsatilla koreana decreased the plasma and hepatic levels of pro-inflammatory cytokines such as IL-1 β, IL-6, TNF-α while increased the level of anti-inflammatory cytokine IL-10 in LPS-exposed rats. Pulsatilla koreana also decreased the plasma levels of other inflammatory mediators such as NO3 -/NO2 -, ICAM-1, PGE2, and CINC-1 in LPS-exposed rats. Although no significant effects were observed in the phagocytic activities, the distribution of lymphocyte population was significantly shifted by the treatment with Pulsatilla koreana. All together, Pulsatilla koreana exerts anti-inflammatory activities in the immune-challenged animals implicating that this Korean herbal medicine is therapeutically useful for the treatment of inflammatory diseases like sepsis.