Lyophilisation and concentration of chitosan/siRNA polyplexes: Influence of buffer composition, oligonucleotide sequence, and hyaluronic acid coating

Revealing two distinct molecular binding modes in polyethyleneimine-DNA polyplexes using infrared spectroscopy

In this study, we use infrared spectroscopy to investigate the molecular binding modes of DNA with linear and branched polyethylenimine (LPEI and BPEI). PEI-based polymers are widely studied as non-viral gene delivery vectors, but their low transfection efficiency limits their clinical success. One key factor affecting their performance is how they bind DNA as it directly impacts the packaging, protection, and release of the cargo in cells. While PEI-DNA binding has traditionally been viewed through the lens of electrostatics, computational models suggest additional binding mechanisms may be involved. Our findings reveal that LPEI and BPEI exhibit two distinct molecular binding modes, which influence DNA packaging into polyplexes. Identifying these binding modes provides critical insights into polymer complexation mechanisms to nucleic acids that can guide the rational design of more efficient and versatile PEI-based gene delivery systems.

Stabilization of chitosan-based nanomedicines in cancer therapy: a review

Chitosan (CS), a versatile and alkaline polysaccharide, has gained significant attention in nanomedicine due to its biocompatibility and biodegradability. In recent years, its applications in cancer therapy, particularly for the delivery of chemotherapeutic drugs, diagnostic agents, and genes, have advanced considerably. However, many CS-based nanomedicines suffer from poor stability in biological fluids, especially under physiological conditions. The neutral pH and the presence of electrolytes in physiological environments reduce the charge density of CS, which can account for this application limitation of CS-based nanomedicines. To improve the stability and prevent dissociation or aggregation of these nanomedicines before reaching the target sites, this review summarizes common stabilization strategies including hydrophilic or hydrophobic modification of CS, as well as incorporation with metal ions (e.g. Fe3+ or Zn2+), complexation with anionic cross-linkers (e.g. TPP) or anionic polymers. Additionally, the review highlights the application of stabilized CS-based nanocarriers in drug delivery, with a particular focus on cancer therapy. The challenges and future perspectives for accelerating the clinical translation of these nanomedicines are also discussed.

Formulate a concentrated highly branched poly(β-amino ester)/DNA polyplex - one step closer to application in lung cystic fibrosis disease

OBJECTIVE

Highly branched poly(β-amino ester) (HPAEs)-based gene therapy holds promise for treating lung cystic fibrosis (CF). However, the translation of HPAEs/DNA nanoparticles into clinical applications poses a significant challenge due to the requirement for high concentrations of the formulation.

METHODS

In this work, a straightforward and scalable concentration method was developed for concentrating HPAEs/DNA polyplexes. A series of different buffers with various pH values and ionic components were initially tested to develop the optimized HPAEs/DNA polyplex formulation. Subsequently, the optimized HPAEs/DNA polyplex formulation was concentrated through lyophilization and ultrafiltration.

RESULTS

The ultrafiltration outperformed the lyophilization in concentration capacity, showing a 24-fold increase in the concentrated formulation compared to the original non-concentrated formulation. The concentration does not disturb the transfection efficiency in lung CF epithelial cells, indicating its potential for lung delivery applications. Moreover, the concentrated HPAEs/DNA polyplex successfully restored the production of CF transmembrane conductance regulator (CFTR) protein in primary lung CF epithelial cells, surpassing the performance of the non-concentrated common gene transfection reagents such as Lipofectamine 3000 and Xfect.

CONCLUSION

The concentrated HPAEs/DNA formulation represents a promising step forward for preclinical testing (e.g. in vivo evaluation), with further research needed to confirm its potential for clinical use.

A review of chitosan in gene therapy: Developments and challenges

Gene therapy, as a revolutionary treatment, has been gaining more and more attention. The key to gene therapy is the selection of suitable vectors for protection of exogenous nucleic acid molecules and enabling their specific release in target cells. While viral vectors have been widely used in researches, non-viral vectors are receiving more attention due to its advantages. Chitosan (CS) has been widely used as non-viral organic gene carrier because of its good biocompatibility and its ability to load large amounts of nucleic acids. This paper summarizes and evaluates the potential of chitosan and its derivatives as gene delivery vector materials, along with factors influencing transfection efficiency, performance evaluation, ways to optimize infectious efficiency, and the current main research development directions. Additionally, it provides an outlook on its future prospects.

Chitosan scaffolds: Expanding horizons in biomedical applications

Chitosan, a natural polysaccharide from chitin, shows promise as a biomaterial for various biomedical applications due to its biocompatibility, biodegradability, antibacterial activity, and ease of modification. This review overviews "chitosan scaffolds" use in diverse biomedical applications. It emphasizes chitosan's structural and biological properties and explores fabrication methods like gelation, electrospinning, and 3D printing, which influence scaffold architecture and mechanical properties. The review focuses on chitosan scaffolds in tissue engineering and regenerative medicine, highlighting their role in bone, cartilage, skin, nerve, and vascular tissue regeneration, supporting cell adhesion, proliferation, and differentiation. Investigations into incorporating bioactive compounds, growth factors, and nanoparticles for improved therapeutic effects are discussed. The review also examines chitosan scaffolds in drug delivery systems, leveraging their prolonged release capabilities and ability to encapsulate medicines for targeted and controlled drug delivery. Moreover, it explores chitosan's antibacterial activity and potential for wound healing and infection management in biomedical contexts. Lastly, the review discusses challenges and future objectives, emphasizing the need for improved scaffold design, mechanical qualities, and understanding of interactions with host tissues. In summary, chitosan scaffolds hold significant potential in various biological applications, and this review underscores their promising role in advancing biomedical science.

Hyaluronic acid-functionalized lipoplexes and polyplexes as emerging nanocarriers for receptor-targeted cancer therapy

Cancer is an intricate disease that develops as a response to a combination of hereditary and environmental risk factors, which then result in a variety of changes to the genome. The cluster of differentiation (CD44) is a type of transmembrane glycoprotein that serves as a potential biomarker for cancer stem cells (CSC) and viable targets for therapeutic intervention in the context of cancer therapy. Hyaluronic acid (HA) is a linear polysaccharide that exhibits a notable affinity for the CD44 receptor. This characteristic renders it a promising candidate for therapeutic interventions aimed at selectively targeting CD44-positive cancer cells. Treating cancer via non-viral vector-based gene delivery has changed the notion of curing illness through the incorporation of therapeutic genes into the organism. The objective of this review is to provide an overview of various hyaluronic acid-modified lipoplexes and polyplexes as potential drug delivery methods for specific forms of cancer by effectively targeting CD44.

Managing Apoptosis in Lung Diseases using Nano-assisted Drug Delivery System

Several factors exist that limit the efficacy of lung cancer treatment. These may be tumor-specific delivery of therapeutics, airway geometry, humidity, clearance mechanisms, presence of lung diseases, and therapy against tumor cell resistance. Advancements in drug delivery using nanotechnology based multifunctional nanocarriers, have emerged as a viable method for treating lung cancer with more efficacy and fewer adverse effects. This review does a thorough and critical examination of effective nano-enabled approaches for lung cancer treatment, such as nano-assisted drug delivery systems. In addition, to therapeutic effectiveness, researchers have been working to determine several strategies to produce nanotherapeutics by adjusting the size, drug loading, transport, and retention. Personalized lung tumor therapies using sophisticated nano modalities have the potential to provide great therapeutic advantages based on individual unique genetic markers and disease profiles. Overall, this review provides comprehensive information on newer nanotechnological prospects for improving the management of apoptosis in lung cancer.

The Impact of Metal Nanoparticles on Female Reproductive System: Risks and Opportunities

Humans have always been exposed to tiny particles via dust storms, volcanic ash, and other natural processes, and our bodily systems are well adapted to protect us from these potentially harmful external agents. However, technological advancement has dramatically increased the production of nanometer-sized particles or nanoparticles (NPs), and many epidemiological studies have confirmed a correlation between NP exposure and the onset of cardiovascular diseases and various cancers. Among the adverse effects on human health, in recent years, potential hazards of nanomaterials on female reproductive organs have received increasing concern. Several animal and human studies have shown that NPs can translocate to the ovary, uterus, and placenta, thus negatively impacting female reproductive potential and fetal health. However, NPs are increasingly being used for therapeutic purposes as tools capable of modifying the natural history of degenerative diseases. Here we briefly summarize the toxic effects of few but widely diffused NPs on female fertility and also the use of nanotechnologies as a new molecular approach for either specific pathological conditions, such as ovarian cancer and infertility, or the cryopreservation of gametes and embryos.

Designing siRNA/chitosan-methacrylate complex nanolipogel for prolonged gene silencing effects

Despite immense revolutionary therapeutics potential, sustaining release of active small interfering RNA (siRNA) remains an arduous challenge. The development of nanoparticles with siRNA sustained release capabilities provides an avenue to enhance the therapeutic efficacy of gene-based therapy. Herein, we present a new system based on the encapsulation of siRNA/chitosan-methacrylate (CMA) complexes into liposomes to form UV crosslinkable Nanolipogels (NLGs) with sustained siRNA-release properties in vitro. We demonstrated that the CMA nanogel in NLGs can enhance the encapsulation efficiency of siRNA and provide sustained release of siRNA up to 28 days. To understand the particle mechanism of cellular entry, multiple endocytic inhibitors have been used to investigate its endocytosis pathways. The study saw positively charged NLGs entering cells via multiple endocytosis pathways, facilitating endosomal escape and slowly releasing siRNA into the cytoplasm. Transfection experiments confirmed that the crosslinked NLG delivery system provides effective transfection and prolonged silencing effect up to 14 days in cell cultures. We expect that this sustained-release siRNA NLG platform would be of interest in both fundamental biological studies and in clinical applications to extend the use of siRNA-based therapies.

Nucleic Acid Delivery from Granular Hydrogels

Nucleic acid delivery has applications ranging from tissue engineering to vaccine development to infectious disease. Cationic polymer condensed nucleic acids are used with surface-coated porous scaffolds and are able to promote long-term gene expression. However, due to surface loading of the scaffold, there is a limit to the amount of nucleic acid that can be loaded, resulting in decreasing expression rate over time. In addition, surface-coated scaffolds are generally non-injectable. Here, it is demonstrated that cationic polymer condensed nucleic acids can be effectively loaded into injectable granular hydrogel scaffolds by stabilizing the condensed nucleic acid into a lyophilized powder, loading the powder into a bulk hydrogel, and then fragmenting the loaded hydrogel. The resulting hydrogel microparticles contain non-aggregated nucleic acid particles, can be annealed post-injection to result in an injectable microporous hydrogel, and can effectively deliver nucleic acids to embedded cells with a constant expression rate. Due to the nature of granular hydrogels, it is demonstrated that mixtures of loaded and unloaded particles and spatially resolved gene expression can be easily achieved. The ability to express genes long term from an injectable porous hydrogel will further open the applications of nucleic acid delivery.

Fundamental and Practical Aspects in the Formulation of Colloidal Polyelectrolyte Complexes of Chitosan and siRNA

The formation of electrostatic interactions between polyanionic siRNA and polycations gives an easy access to the formation of colloidal particles capable of delivering siRNA in vitro or in vivo. Among the polycations used for siRNA delivery, chitosan occupies a special place due to its unique physicochemical and biological properties. In this chapter we describe the fundamental and practical aspects of the formation of colloidal complexes between chitosan and siRNA. The basis of the electrostatic complexation between oppositely charged polyelectrolytes is first introduced with a focus on the specific conditions to obtain stable colloid complex particles. Subsequent, the properties that make chitosan so special are described. In a third part, the main parameters influencing the colloidal properties and stability of siRNA/chitosan complexes are reviewed with emphasis on some practical aspects to consider in the preparation of complexes.

Freeze-drying of nanoparticles: How to overcome colloidal instability by formulation and process optimization

Lyophilization of nanoparticle (NP) suspensions is a promising technology to improve stability, especially during long-term storage, and offers new routes of administration in solid state. Although considered as a gentle drying process, freeze-drying is also known to cause several stresses leading to physical instability, e.g. aggregation, fusion, or content leakage. NPs are heterogeneous regarding their physico-chemical properties which renders them different in their sensitivity to lyophilization stress and upon storage. But still basic concepts can be deducted. We summarize basic colloidal stabilization mechanisms of NPs in the liquid and the dried state. Furthermore, we give information about stresses occurring during the freezing and the drying step of lyophilization. Subsequently, we review the most commonly investigated NP types including lipophilic, polymeric, or vesicular NPs regarding their particle properties, stabilization mechanisms in the liquid state, and important freeze-drying process, formulation and storage strategies. Finally, practical advice is provided to facilitate purposeful formulation and process development to achieve NP lyophilizates with high colloidal stability.

Polymeric Delivery of Therapeutic Nucleic Acids

The advent of genome editing has transformed the therapeutic landscape for several debilitating diseases, and the clinical outlook for gene therapeutics has never been more promising. The therapeutic potential of nucleic acids has been limited by a reliance on engineered viral vectors for delivery. Chemically defined polymers can remediate technological, regulatory, and clinical challenges associated with viral modes of gene delivery. Because of their scalability, versatility, and exquisite tunability, polymers are ideal biomaterial platforms for delivering nucleic acid payloads efficiently while minimizing immune response and cellular toxicity. While polymeric gene delivery has progressed significantly in the past four decades, clinical translation of polymeric vehicles faces several formidable challenges. The aim of our Account is to illustrate diverse concepts in designing polymeric vectors towards meeting therapeutic goals of in vivo and ex vivo gene therapy. Here, we highlight several classes of polymers employed in gene delivery and summarize the recent work on understanding the contributions of chemical and architectural design parameters. We touch upon characterization methods used to visualize and understand events transpiring at the interfaces between polymer, nucleic acids, and the physiological environment. We conclude that interdisciplinary approaches and methodologies motivated by fundamental questions are key to designing high-performing polymeric vehicles for gene therapy.

Instability of therapeutic proteins - An overview of stresses, stabilization mechanisms and analytical techniques involved in lyophilized proteins

Solid-state is the preferred choice for storage of protein therapeutics to improve stability and preserve the biological activity by decreasing the physical and chemical degradation associated with liquid protein formulations. Lyophilization or freeze-drying is an effective drying method to overcome the instability problems of proteins. However, the processing steps (freezing, primary drying and secondary drying) involved in the lyophilization process can expose the proteins to various stress and harsh conditions, leading to denaturation, aggregation often a loss in activity of protein therapeutics. Stabilizers such as sugars and surfactants are often added to protect the proteins against physical stress associated with lyophilization process and storage conditions. Another way to curtail the degradation of proteins due to process related stress is by modification of the lyophilization process. Slow freezing, high nucleation temperature, decreasing the extent of supercooling, and annealing can minimize the formation of the interface (ice-water) by producing large ice crystals with less surface area, thereby preserving the native structure and stability of the proteins. Hence, a thorough understanding of formulation composition, lyophilization process parameters and the choice of analytical methods to characterize and monitor the protein instability is crucial for development of stable therapeutic protein products. This review provides an overview of various stress conditions that proteins might encounter during lyophilization process, mechanisms to improve the stability and analytical techniques to tackle the proteins instability during both freeze-drying and storage.

Brain Delivery of Nanomedicines: Trojan Horse Liposomes for Plasmid DNA Gene Therapy of the Brain

Non-viral gene therapy of the brain is enabled by the development of plasmid DNA brain delivery technology, which requires the engineering and manufacturing of nanomedicines that cross the blood-brain barrier (BBB). The development of such nanomedicines is a multi-faceted problem that requires progress at multiple levels. First, the type of nanocontainer, e.g., nanoparticle or liposome, which encapsulates the plasmid DNA, must be developed. Second, the type of molecular Trojan horse, e.g., peptide or receptor-specific monoclonal antibody (MAb), must be selected for incorporation on the surface of the nanomedicine, as this Trojan horse engages specific receptors expressed on the BBB, and the brain cell membrane, to trigger transport of the nanomedicine from blood into brain cells beyond the BBB. Third, the plasmid DNA must be engineered without bacterial elements, such as antibiotic resistance genes, to enable administration to humans; the plasmid DNA must also be engineered with tissue-specific gene promoters upstream of the therapeutic gene, to insure gene expression in the target organ with minimal off-target expression. Fourth, upstream manufacturing of the nanomedicine must be developed and scalable so as to meet market demand for the target disease, e.g., annual long-term treatment of 1,000 patients with an orphan disease, short term treatment of 10,000 patients with malignant glioma, or 100,000 patients with new onset Parkinson's disease. Fifth, downstream manufacturing problems, such as nanomedicine lyophilization, must be solved to ensure the nanomedicine has a commercially viable shelf-life for treatment of CNS disease in humans.

Lyoprotectant Optimization for the Freeze-Drying of Receptor-Targeted Trojan Horse Liposomes for Plasmid DNA Delivery

Trojan horse liposomes (THLs) are a form of ligand-targeted nanomedicine, where a plasmid DNA is encapsulated in the interior of a 100-150 nm pegylated liposome, and the tips of a fraction of the surface pegylated strands are covalently linked to a receptor-specific monoclonal antibody (MAb) via a thio-ether linkage. The goal of this work was to develop a lyophilization methodology that enables retention of the structure and function of the THLs following the freeze-drying/hydration process. THL fusion and leakage of plasmid DNA were observed with several lyoprotectants, including trehalose, hyaluronic acid, γ-cyclodextrin, or sulfobutylether-β-cyclodextrin. However, the use of hydroxypropyl-γ-cyclodextrin, at a 40:1 wt/wt ratio relative to the THL phospholipid, eliminated liposome fusion and produced high retention of encapsulated plasmid DNA and THL-mediated gene expression after lyophilization followed by hydration. The freeze-dried THL cake was amorphous without cavitation, and the diameters and functional properties of the THLs were preserved following hydration of cakes stored for at least six months. Intravenous administration of the hydrated freeze-dried THLs in the Rhesus monkey demonstrated the safety of the formulation. Blood plasmid DNA was measured with a quantitative polymerase chain reaction method, which enabled a pharmacokinetics analysis of the blood clearance of the THL-encapsulated plasmid DNA in the primate. The work shows that optimization of the lyoprotectant enables long-term storage of the MAb-targeted DNA encapsulated liposomes in the freeze-dried state.

Polyplexes for gene and nucleic acid delivery: Progress and bottlenecks

Gene and nucleic acid delivery constitute a huge biological challenge and several attempts have been made by research laboratories to address this issue. Cationic polymers and cationic lipids (positively charged carriers) can be utilized for the transport of these biomolecules. Polyplexes (PPs) are interpolyelectrolyte complexes which are spontaneously formed through the electrostatic condensation between nucleic acid and a cationic polymer. PPs are capable of high-density payload condensation leading to cell internalization and subsequent protection from enzymatic degradation. Most cationic polymers can cross extracellular barriers, but it is more challenging to overcome intracellular barriers (efficient disassembly and endosomal escape). In this review, the use of PPs for gene and nucleic acid delivery is discussed.

Efficiency of Chitosan/Hyaluronan-Based mRNA Delivery Systems In Vitro: Influence of Composition and Structure

Messenger RNA (mRNA)-containing nanoparticles were produced by electrostatic complexation with a library of pharmaceutical grade chitosans with different degrees of deacetylation and hyaluronic acids (HAs) (native vs. sulfated). Polymer length (Mn), HA degree of sulfation (DS), and amine to phosphate to carboxyl + sulfate (from HA) ratio (N:P:C) were controlled. In vitro transfections were performed in the presence/absence of trehalose and at different pH. Particle size and ζ-potential were correlated with transfection efficiency. Polymer length and charge densities (degree of deacetylation, degree of sulfation) of both HA and chitosan had a direct influence on transfection efficiency through modulation of avidity to mRNA. N:P:C ratio, trehalose, mixing concentration, and nucleic acid dose influenced transfection efficiency with optimized formulations reaching ∼60%-65% transfection efficiency relative to commercially available lipid control with no apparent toxicity for transfection at slightly acidic pH 6.5.

Targeting siRNA in colorectal cancer therapy: Nanotechnology comes into view

Colorectal cancer (CRC) is known as one of the most important causes of death and mortality worldwide. Although several efforts have been made for finding new therapies, no achievements have been made in this area. Multidrug resistance (MDR) mechanisms are one of the key factors that could lead to the failure of chemotherapy. Moreover, it has been shown that various chemotherapy drugs are associated with several side effects. Hence, it seems that finding new drugs or new therapeutic platforms is required. Among different therapeutic approaches, utilization of nanoparticles (NPs) for targeting a variety of molecules such as siRNAs are associated with good results for the treatment of CRC. Targeting siRNA-mediated NPs could turn off the effects of oncogenes and MDR-related genes. In the current study, we summarized various siRNAs targeted by NPs which could be used for the treatment of CRC. Moreover, we highlighted other routes such as liposome for targeting siRNAs in CRC therapy.

Nanoparticle-siRNA: a potential strategy for ovarian cancer therapy?

Ovarian cancer is one of the most common causes of mortality throughout the world. Unfortunately, chemotherapy has failed to cure advanced cancers developing multidrug resistance (MDR). Moreover, it has critical side effects because of nonspecific toxicity. Thanks to specific silencing of oncogenes and MDR-associated genes, nano-siRNA drugs can be a great help address the limitations of chemotherapy. Here, we review the current advances in nanoparticle-mediated siRNA delivery strategies such as polymeric- and lipid-based systems, rigid nanoparticles and nanoparticles coupled to specific ligand systems. Nanoparticle-based codelivery of anticancer drugs and siRNA targeting various mechanisms of MDR is a cutting-edge strategy for ovarian cancer therapy, which is completely discussed in this review.

Natural Polysaccharides for siRNA Delivery: Nanocarriers Based on Chitosan, Hyaluronic Acid, and Their Derivatives

Natural polysaccharides are frequently used in the design of drug delivery systems due to their biocompatibility, biodegradability, and low toxicity. Moreover, they are diverse in structure, size, and charge, and their chemical functional groups can be easily modified to match the needs of the final application and mode of administration. This review focuses on polysaccharidic nanocarriers based on chitosan and hyaluronic acid for small interfering RNA (siRNA) delivery, which are highly positively and negatively charged, respectively. The key properties, strengths, and drawbacks of each polysaccharide are discussed. In addition, their use as efficient nanodelivery systems for gene silencing applications is put into context using the most recent examples from the literature. The latest advances in this field illustrate effectively how chitosan and hyaluronic acid can be modified or associated with other molecules in order to overcome their limitations to produce optimized siRNA delivery systems with promising in vitro and in vivo results.

Interleukin-1 receptor antagonist protein (IL-1Ra) and miR-140 overexpression via pNNS-conjugated chitosan-mediated gene transfer enhances the repair of full-thickness cartilage defects in a rabbit model

Objectives

Previously, we reported the improved transfection efficiency of a plasmid DNA-chitosan (pDNA-CS) complex using a phosphorylatable nuclear localization signal-linked nucleic kinase substrate short peptide (pNNS) conjugated to chitosan (pNNS-CS). This study investigated the effects of pNNS-CS-mediated miR-140 and interleukin-1 receptor antagonist protein (IL-1Ra) gene transfection both in rabbit chondrocytes and a cartilage defect model.

Methods

The pBudCE4.1-miR-140, pBudCE4.1-IL-1Ra, and negative control pBudCE4.1 plasmids were constructed and combined with pNNS-CS to form pDNA/pNNS-CS complexes. These complexes were transfected into chondrocytes or injected into the knee joint cavity.

Results

High IL-1Ra and miR-140 expression levels were detected both in vitro and in vivo. In vitro, compared with the pBudCE4.1 group, the transgenic group presented with significantly increased chondrocyte proliferation and glycosaminoglycan (GAG) synthesis, as well as increased collagen type II alpha 1 chain (COL2A1), aggrecan (ACAN), and TIMP metallopeptidase inhibitor 1 (TIMP-1) levels. Nitric oxide (NO) synthesis was reduced, as were a disintegrin and metalloproteinase with thrombospondin type 1 motif 5 (ADAMTS-5) and matrix metalloproteinase (MMP)-13 levels. In vivo, the exogenous genes reduced the synovial fluid GAG and NO concentrations and the ADAMTS-5 and MMP-13 levels in cartilage. In contrast, COL2A1, ACAN, and TIMP-1 levels were increased, and the cartilage Mankin score was decreased in the transgenic group compared with the pBudCE4.1 group. Double gene combination produced greater efficacies than each single gene, both in vitro and in vivo.

Conclusion

This study suggests that pNNS-CS is a good candidate for treating cartilage defects via gene therapy, and that IL-1Ra in combination with miR-140 produces promising biological effects on cartilage defects.

Cite this article: R. Zhao, S. Wang, L. Jia, Q. Li, J. Qiao, X. Peng. Interleukin-1 receptor antagonist protein (IL-1Ra) and miR-140 overexpression via pNNS-conjugated chitosan-mediated gene transfer enhances the repair of full-thickness cartilage defects in a rabbit model. Bone Joint Res 2019;8:165–178. DOI: 10.1302/2046-3758.83.BJR-2018-0222.R1.

pNNS-Conjugated Chitosan Mediated IGF-1 and miR-140 Overexpression in Articular Chondrocytes Improves Cartilage Repair

The aim of the present study was to investigate the effects of phosphorylatable nucleus localization signal linked nucleic kinase substrate short peptide (^pNNS)-conjugated chitosan (^pNNS-CS) mediated miR-140 and IGF-1 in both rabbit chondrocytes and cartilage defects model. ^pNNS-CS was combined with pBudCE4.1-IGF-1, pBudCE4.1-miR-140, and negative control pBudCE4.1 to form pDNA/^pNNS-CS complexes. Then these complexes were transfected into chondrocytes or injected intra-articularly into the knee joints. High levels of IGF-1 and miR-140 expression were detected both in vitro and in vivo. Compared with pBudCE4.1 group, in vitro, the transgenic groups significantly promoted chondrocyte proliferation, increased glycosaminoglycan (GAG) synthesis, and ACAN, COL2A1, and TIMP-1 levels, and reduced the levels of nitric oxide (NO), MMP-13, and ADAMTS-5. In vivo, the exogenous genes enhanced COL2A1, ACAN, and TIMP-1 expression in cartilage and reduced cartilage Mankin score and the contents of NO, IL-1β, TNF-α, and GAG contents in synovial fluid of rabbits, MMP-13, ADAMTS-5, COL1A2, and COL10A1 levels in cartilage. Double gene combination showed better results than single gene. This study indicate that ^pNNS-CS is a better gene delivery vehicle in gene therapy for cartilage defects and that miR-140 combination IGF-1 transfection has better biologic effects on cartilage defects.