Non-viral Gene Delivery Methods for Bone and Joints

Abstract

Viral carrier transport efficiency of gene delivery is high, depending on the type of vector. However, viral delivery poses significant safety concerns such as inefficient/unpredictable reprogramming outcomes, genomic integration, as well as unwarranted immune responses and toxicity. Thus, non-viral gene delivery methods are more feasible for translation as these allow safer delivery of genes and can modulate gene expression transiently both in vivo, ex vivo, and in vitro. Based on current studies, the efficiency of these technologies appears to be more limited, but they are appealing for clinical translation. This review presents a summary of recent advancements in orthopedics, where primarily bone and joints from the musculoskeletal apparatus were targeted. In connective tissues, which are known to have a poor healing capacity, and have a relatively low cell-density, i.e., articular cartilage, bone, and the intervertebral disk (IVD) several approaches have recently been undertaken. We provide a brief overview of the existing technologies, using nano-spheres/engineered vesicles, lipofection, and in vivo electroporation. Here, delivery for microRNA (miRNA), and silencing RNA (siRNA) and DNA plasmids will be discussed. Recent studies will be summarized that aimed to improve regeneration of these tissues, involving the delivery of bone morphogenic proteins (BMPs), such as BMP2 for improvement of bone healing. For articular cartilage/osteochondral junction, non-viral methods concentrate on targeted delivery to chondrocytes or MSCs for tissue engineering-based approaches. For the IVD, growth factors such as GDF5 or GDF6 or developmental transcription factors such as Brachyury or FOXF1 seem to be of high clinical interest. However, the most efficient method of gene transfer is still elusive, as several preclinical studies have reported many different non-viral methods and clinical translation of these techniques still needs to be validated. Here we discuss the non-viral methods applied for bone and joint and propose methods that can be promising in clinical use.

Cutting Edge Endogenous Promoting and Exogenous Driven Strategies for Bone Regeneration

“…These strategies consist of both viral and non-viral methods, the latter being the preferred one for bone regeneration as it is considered safer (avoids immunogenicity and integration of the host genome). Non-viral gene delivery is often performed using plasmid DNA (pDNA); these circular, small, double-stranded DNA structures are stable, can be readily produced in bacteria and customized with a variety of different promoters [ 175 ]. However, the drawback focuses on the lower efficiency that this technique shows compared to viral methods.…”

Cell-Permeable Oct4 Gene Delivery Enhances Stem Cell-like Properties of Mouse Embryonic Fibroblasts

“…The viral carrier transport efficiency of gene delivery can be high, depending on the type of vector used [15,27]; however, the risk of integration of viral DNA into the host genome raises potential safety issues for potential therapeutics and poses concerns like inefficient/unpredictable reprogramming outcomes, genomic integration, and unwarranted immune responses and toxicity. Therefore, several non-viral delivery methods have been reported as alternative ways to incorporate the transcription factors necessary for direct cell fate conversion or to promote stem cell-like properties [39,40]. Emerging studies have reported LMWP fragments as possible nontoxic substitutes for protamine in clinical heparin neutralization [41].…”

Direct Reprogramming of Somatic Cells to Neurons: Pros and Cons of Chemical Approach

“…Alternative non-viral methods, such as transient transfection and electroporation (for retina [ 40 , 41 ], for brain [ 42 – 44 ]) can also be applied. However, due to their low efficiency, transgene silencing, inflammation and poor nuclear uptake, are less commonly used in transdifferentiation studies [ 45 ]. Lately, the use of neural exosomes [ 46 ] and the protein transduction domains (PTDs) fused to TFs allow the direct delivery of exogenous TFs avoiding the problems associated with DNA integration into the host genome [ 47 ] opening up new strategies for possible clinical applications.…”