Tailoring combinatorial lipid nanoparticles for intracellular delivery of nucleic acids, proteins, and drugs

Lipid nanoparticle (LNP)-based drug delivery systems have become the most clinically advanced non-viral delivery technology. LNPs can encapsulate and deliver a wide variety of bioactive agents, including the small molecule drugs, proteins and peptides, and nucleic acids. However, as the physicochemical properties of small- and macromolecular cargos can vary drastically, every LNP carrier system needs to be carefully tailored in order to deliver the cargo molecules in a safe and efficient manner. Our group applied the combinatorial library synthesis approach and in vitro and in vivo screening strategy for the development of LNP delivery systems for drug delivery. In this Review, we highlight our recent progress in the design, synthesis, characterization, evaluation, and optimization of combinatorial LNPs with novel structures and properties for the delivery of small- and macromolecular therapeutics both in vitro and in vivo. These delivery systems have enormous potentials for cancer therapy, antimicrobial applications, gene silencing, genome editing, and more. We also discuss the key challenges to the mechanistic study and clinical translation of new LNP-enabled therapeutics.

Enzyme-instructed hybrid nanogel/nanofiber oligopeptide hydrogel for localized protein delivery

Enzyme-catalysis self-assembled oligopeptide hydrogel holds great interest in drug delivery, which has merits of biocompatibility, biodegradability and mild gelation conditions. However, its application for protein delivery is greatly limited by inevitable degradation of enzyme on the encapsulated proteins leading to loss of protein activity. Moreover, for the intracellularly acted proteins, cell membrane as a primary barrier hinders the transmembrane delivery of proteins. The internalized proteins also suffer from acidic and enzymatic degradation in endosomes and lysosomes. We herein develop a protease-manipulated hybrid nanogel/nanofiber hydrogel for localized delivery of intracellularly acted proteins. The embedded polymeric nanogels (CytoC/aNGs) preserve activity of cytochrome

Designing the new generation of intelligent biocompatible carriers for protein and peptide delivery

Therapeutic proteins and peptides have revolutionized treatment for a number of diseases, and the expected increase in macromolecule-based therapies brings a new set of challenges for the pharmaceutics field. Due to their poor stability, large molecular weight, and poor transport properties, therapeutic proteins and peptides are predominantly limited to parenteral administration. The short serum half-lives typically require frequent injections to maintain an effective dose, and patient compliance is a growing issue as therapeutic protein treatments become more widely available. A number of studies have underscored the relationship of subcutaneous injections with patient non-adherence, estimating that over half of insulin-dependent adults intentionally skip injections. The development of oral formulations has the potential to address some issues associated with non-adherence including the interference with daily activities, embarrassment, and injection pain. Oral delivery can also help to eliminate the adverse effects and scar tissue buildup associated with repeated injections. However, there are several major challenges associated with oral delivery of proteins and peptides, such as the instability in the gastrointestinal (GI) tract, low permeability, and a narrow absorption window in the intestine. This review provides a detailed overview of the oral delivery route and associated challenges. Recent advances in formulation and drug delivery technologies to enhance bioavailability are discussed, including the co-administration of compounds to alter conditions in the GI tract, the modification of the macromolecule physicochemical properties, and the use of improved targeted and controlled release carriers.

Nose-to-brain delivery of macromolecules mediated by cell-penetrating peptides

Brain delivery of macromolecular therapeutics (e.g., proteins) remains an unsolved problem because of the formidable blood-brain barrier (BBB). Although a direct pathway of nose-to-brain transfer provides an answer to circumventing the BBB and has already been intensively investigated for brain delivery of small drugs, new challenges arise for intranasal delivery of proteins because of their larger size and hydrophilicity. In order to overcome the barriers and take advantage of available pathways (e.g., epithelial tight junctions, uptake by olfactory neurons, transport into brain tissues, and intra-brain diffusion), a low molecular weight protamine (LMWP) cell-penetrating peptide was utilized to facilitate nose-to-brain transport. Cell-penetrating peptides (CPP) have been widely used to mediate macromolecular delivery through many kinds of biobarriers. Our results show that conjugates of LMWP-proteins are able to effectively penetrate into the brain after intranasal administration. The CPP-based intranasal method highlights a promising solution for protein therapy of brain diseases.

VP22 herpes simplex virus protein can transduce proteins into stem cells

The type I herpes simplex virus VP22 tegument protein is abundant and well known for its ability to translocate proteins from one cell to the other. In spite of some reports questioning its ability to translocate proteins by attributing the results observed to fixation artifacts or simple attachment to the cell membrane, VP22 has been used to deliver several proteins into different cell types, triggering the expected cell response. However, the question of the ability of VP22 to enter stem cells has not been addressed. We investigated whether VP22 could be used as a tool to be applied in stem cell research and differentiation due to its capacity to internalize other proteins without altering the cell genome. We generated a VP22.eGFP construct to evaluate whether VP22 could be internalized and carry another protein with it into two different types of stem cells, namely adult human dental pulp stem cells and mouse embryonic stem cells. We generated a VP22.eGFP fusion protein and demonstrated that, in fact, it enters stem cells. Therefore, this system may be used as a tool to deliver various proteins into stem cells, allowing stem cell research, differentiation and the generation of induced pluripotent stem cells in the absence of genome alterations.

In situ tissue regeneration through host stem cell recruitment

The field of tissue engineering has made steady progress in translating various tissue applications. Although the classical tissue engineering strategy, which involves the use of culture-expanded cells and scaffolds to produce a tissue construct for implantation, has been validated, this approach involves extensive cell expansion steps, requiring a lot of time and laborious effort before implantation. To bypass this ex vivo process, a new approach has been introduced. In situ tissue regeneration utilizes the body's own regenerating capacity by mobilizing host endogenous stem cells or tissue-specific progenitor cells to the site of injury. This approach relies on development of a target-specific biomaterial scaffolding system that can effectively control the host microenvironment and mobilize host stem/progenitor cells to target tissues. An appropriate microenvironment provided by implanted scaffolds would facilitate recruitment of host cells that can be guided to regenerating structural and functional tissues.

Advance of heparin-coated and heparin-based nanoparticles / 中国药学杂志

OBJECTIVE: To summarize advances in heparin nanoparticles. METHODS: Literatures recently published were searched and reviewed for the structures, synthetic methods, properties and application prospects of heparin nanoparticle. RESULTS: Nowadays, researches are focused on heparin-conjugated nanoparticles and nanoparticles assembled by heparin or heparin derivatives. The former can improve biocompatibility, targeting ability and drug loading capacity, while the latter were utilized in targeting transportation of protein and antitumor drugs. CONCLUSION: The combination of nanoparticles and heparin may bring new possibilities for clinical applications of heparin and improve the biological capabilities of existing medicinal nanoparticles. However, a great deal of problems, such as preparation process, pharmacology and toxicology evaluation, and quality control should be resolved first.

Analysis of GDNF(△N39)-R9 Fusion Protein Delivery Across The Cellular Membrane,Blood Brain Barrier and Biological Function / 生物化学与生物物理进展

In order to study the application of glial cell line-derived neurotrophic factor(GDNF)in clinic,gene mutation,fusion protein expression in E.coli and purification methods have been used to obtain the fragments of GDNF,GDNF(△N39),GDNF(△N39)-R9.Using primary cultured dopaminergic neurons and PC12 cells with transfected with GFR?1 and Ret to observe their biological function and cytotoxicity.Using B-Endo3 cells and Transwell method to analyze their delivery across the cellular membrane and blood brain barrier.The results show that GDNF(△N39)-R9 has the same neurotrophic function with wild GDNF and nearly no cytotoxicity to dopaminergic neurons and PC12-GFR?1-Ret cells and can get through effectually the cellular membrane and simulacrum of blood brain barrier with matrigel and B-Endo3.

Proliferation of Corneal Endothelial Cells by Delivery of SV40 Large T Antigen

PURPOSE: To determine whether the delivery of the SV40 large T-antigen is a feasible method for transiently inducing proliferation of corneal endothelial cells, we delivered liposome-protein complex into bovine corneal endothelial cells(BCEC). METHOD: SV40 large T-antigen protein was introduced into BCEC and positive cells were identified by immunohistochemistry. Quiescent BCECs were double-labeled using BrdU as a measure of de novo DNA synthesis and the Ki-67 was detected by standard immunohistochemical methods. RESULT: The treatment of quiescent BCECs with large T antigen caused an increase in BrdU incorporation and Ki-67 expression. It was tested by time-course study. CONCLUSION: This finding suggests that liposome-mediated delivery of transforming proteins could be a method to transiently induce corneal endothelial cell proliferation.

VP22 Enhanced Intercellular Trafficking of HSV Thymidine Kinase Promoted an Effective Cell Killing Effect at Lower Concentration of Ganciclovir / 中国肿瘤生物治疗杂志

Objective: To explore the enhanced cell killing effect of HSV tk using VP22 intercellular traffciking. Methods: The chimeric genes were constructed by fusing a marker gene for the green fluorescent protein (GFP) or a prodrug enzyme gene for the Herpes simplex virus thymidine kinase (HSV tk) with that of VP22. After being sequenced, the fusion genes were transferred into 293T or COS7 cells. The transfection efficiency and intercellular trafficking were certified using Western blot and immunofluorescence.The cell proliferation was detected through MTT method in the different concentration of GCV and under indicated between transfected cells and untransfected cells. The supernatant of transfected cells was used to culture the untransfected cells to test whether the bystander effect could transferred by media. Results: The gene insertion was proved correct using PCR and DNA sequencing. When the fusion genes were transferred into 293T or COS7 cells at transfection efficiency of 25%～30%, fusion proteins were expressed and efficient intercellular trafficking was demonstrated.The VP22 HSV tk, as a prodrug enzyme fused with VP22, showed an amplified cell killing effect in the presence of GCV as low as 0.1 ?g/ml. Further quantification of the bystander effect showed that cell killing increased with higher proportion of VP22 HSV tk expressing cells. The bystander effect could not be transferred through media. Conclusion: These results clearly indicate that VP22 enhanced intercellular trafficking promotes tumor cell killing effect of HSV tk/GCV.