Hyperbranched cationic polysaccharide derivatives for efficient siRNA delivery and diabetic wound healing enhancement

Targeted delivery systems of siRNA based on ionizable lipid nanoparticles and cationic polymer vectors

As an emerging therapeutic tool, small interfering RNA (siRNA) had the capability to down-regulate nearly all human mRNAs via sequence-specific gene silencing. Numerous studies have demonstrated the substantial potential of siRNA in the treatment of broad classes of diseases. With the discovery and development of various delivery systems and chemical modifications, six siRNA-based drugs have been approved by 2024. The utilization of siRNA-based therapeutics has significantly propelled efforts to combat a wide array of previously incurable diseases and advanced at a rapid pace, particularly with the help of potent targeted delivery systems. Despite encountering several extracellular and intracellular challenges, the efficiency of siRNA delivery has been gradually enhanced. Currently, targeted strategies aimed at improving potency and reducing toxicity played a crucial role in the druggability of siRNA. This review focused on recent advancements on ionizable lipid nanoparticles (LNPs) and cationic polymer (CP) vectors applied for targeted siRNA delivery. Based on various types of targeted modifications, we primarily described delivery systems modified with receptor ligands, peptides, antibodies, aptamers and amino acids. Finally, we discussed the challenges and opportunities associated with siRNA delivery systems based on ionizable LNPs and CPs vectors.

Advances in nucleic acid delivery strategies for diabetic wound therapy

In recent years, the prevalence of diabetic wounds has significantly increased, posing a substantial medical challenge due to their propensity for infection and delayed healing. These wounds not only increase mortality rates but also lead to amputations and severe mobility issues. To address this, advancements in bioactive molecules such as genes, growth factors, proteins, peptides, stem cells, and exosomes into targeted gene therapies have emerged as a preferred strategy among researchers. Additionally, the integration of photothermal therapy (PTT), nucleic acid, and gene therapy, along with 3D printing technology and the layer-by-layer (LBL) self-assembly approach, shows promise in diabetic wound treatment. Effective delivery of small interfering RNA (siRNA) relies on gene vectors. This review provides an in-depth exploration of the pathophysiological characteristics observed in diabetic wounds, encompassing diminished angiogenesis, heightened levels of reactive oxygen species, and impaired immune function. It further examines advancements in nucleic acid delivery, targeted gene therapy, advanced drug delivery systems, layer-by-layer (LBL) techniques, negative pressure wound therapy (NPWT), 3D printing, hyperbaric oxygen therapy, and ongoing clinical trials. Through the integration of recent research insights, this review presents innovative strategies aimed at augmenting the multifaceted management of diabetic wounds, thus paving the way for enhanced therapeutic outcomes in the future.

Healing the diabetic wound: Unlocking the secrets of genes and pathways

Diabetic wounds (DWs) are open sores that can occur anywhere on a diabetic patient's body. They are often complicated by infections, hypoxia, oxidative stress, hyperglycemia, and reduced growth factors and nucleic acids. The healing process involves four phases: homeostasis, inflammation, proliferation, and remodeling, regulated by various cellular and molecular events. Numerous genes and signaling pathways such as VEGF, TGF-β, NF-κB, PPAR-γ, MMPs, IGF, FGF, PDGF, EGF, NOX, TLR, JAK-STAT, PI3K-Akt, MAPK, ERK, JNK, p38, Wnt/β-catenin, Hedgehog, Notch, Hippo, FAK, Integrin, and Src pathways are involved in these events. These pathways and genes are often dysregulated in DWs leading to impaired healing. The present review sheds light on the pathogenesis, healing process, signaling pathways, and genes involved in DW. Further, various therapeutic strategies that target these pathways and genes via nanotechnology are also discussed. Additionally, clinical trials on DW related to gene therapy are also covered in the present review.

The sweetest polymer nanoparticles: opportunities ahead for glycogen in nanomedicine

Most cells take simple sugar (α-D-glucose) and assemble it into highly dense polysaccharide nanoparticles called glycogen. This is achieved through the action of multiple coupled-enzymatic reactions, yielding the cellular store of polymerised glucose to be degraded in times of metabolic need. These nanoparticles can be readily isolated from various animal tissues and plants, and are commercially available on a large scale. Importantly, glycogen is highly water soluble, non-toxic, low-fouling, and biodegradable, making it an attractive nanoparticle for use in nanomedicine, for both diagnosing and treating disease. This concept has been pursued actively recently, with exciting results on a variety of fronts, especially for targeting specific tissues and delivering nucleic acid and peptide cargo. In this perspective, the role of glycogen in nanomedicine going forward is discussed, with opportunities highlighted of where these sugary nanoparticles fit into the problem of treating disease.

Nanotechnology strategies to address challenges in topical and cellular delivery of siRNAs in skin disease therapy

Gene therapy is one of the most advanced therapies in current medicine. In particular, interference RNA-based therapy by small interfering RNA (siRNA) has gained attention in recent years as it is a highly versatile, selective and specific therapy. In dermatological conditions, topical delivery of siRNA offers numerous therapeutic advantages, mainly by inhibiting the expression of target transcripts directly in the skin. However, crossing the stratum corneum and overcoming intracellular barriers is an inherent challenge. Substantial efforts by scientists have moved towards the use of multimodal and multifunctional nanoparticles to overcome these barriers and achieve greater bioavailability in their site of action, the cytoplasm. In this review the most innovative strategies based on nanoparticle and physical methods are presented, as well as the design principles and the main factors that contribute to the performance of these systems. This review also highlights the synergistic contributions of medicine, nanotechnology, and molecular biology to advancing translational research into siRNA-based therapeutics for skin diseases.

Cationic Starch Nanoparticles for Enhancing CpG Oligodeoxynucleotide-Mediated Antitumor Immunity

CpG ODNs demonstrate a significant promise for immunotherapy. However, their application is limited owing to quick DNase digestion and inadequate cellular internalization. Transportation of CpG ODNs into immune cells is crucial. Although viral vectors exhibit high transfection efficiency, safety risks, high cost, and low carrying capacity remain big obstacles. Herein, a novel CpG ODNs vector was fabricated by using starch. Starch was ultrasonicated and simply aminated (NH2-St) through grafting with diethylenetriamine, which was spherical with a diameter of 50 nm. NH2-St possessed good biocompatibility. Cationic NH2-St encapsulated CpG ODNs well and possessed a high loading capacity of 317 μg/mg. NH2-St protected CpG ODNs from nuclease digestion and significantly enhanced their cellular uptake. NH2-St/CpG induced the potent secretion of antitumor cytokines from macrophages and effectively suppressed the growth of tumor cells. This work highlights the promise of starch for CpG ODNs delivery, which brings new hope for cancer immunotherapy.

Dually Modified Cellulose as a Non-Viral Vector for the Delivery and Uptake of HDAC3 siRNA

RNA interference can be applied to different target genes for treating a variety of diseases, but an appropriate delivery system is necessary to ensure the transport of intact siRNAs to the site of action. In this study, cellulose was dually modified to create a non-viral vector for HDAC3 short interfering RNA (siRNA) transfer into cells. A guanidinium group introduced positive charges into the cellulose to allow complexation of negatively charged genetic material. Furthermore, a biotin group fixed by a polyethylene glycol (PEG) spacer was attached to the polymer to allow, if required, the binding of targeting ligands. The resulting polyplexes with HDAC3 siRNA had a size below 200 nm and a positive zeta potential of up to 15 mV. For N/P ratio 2 and higher, the polymer could efficiently complex siRNA. Nanoparticles, based on this dually modified derivative, revealed a low cytotoxicity. Only minor effects on the endothelial barrier integrity and a transfection efficiency in HEK293 cells higher than Lipofectamine 2000TM were found. The uptake and release of the polyplexes were confirmed by immunofluorescence imaging. This study indicates that the modified biopolymer is an auspicious biocompatible non-viral vector with biotin as a promising moiety.

Advanced dendritic glucan-derived biomaterials: From molecular structure to versatile applications

There is considerable interest in the development of advanced biomaterials with improved or novel functionality for diversified applications. Dendritic glucans, such as phytoglycogen and glycogen, are abundant biomaterials with highly branched three-dimensional globular architectures, which endow them with unique structural and functional attributes, including small size, large specific surface area, high water solubility, low viscosity, high water retention, and the availability of numerous modifiable surface groups. Dendritic glucans can be synthesized by in vivo biocatalysis reactions using glucosyl-1-phosphate as a substrate, which can be obtained from plant, animal, or microbial sources. They can also be synthesized by in vitro methods using sucrose or starch as a substrate, which may be more suitable for large-scale industrial production. The large numbers of hydroxyl groups on the surfaces of dendritic glucan provide a platform for diverse derivatizations, including nonreducing end, hydroxyl functionalization, molecular degradation, and conjugation modifications. Due to their unique physicochemical and functional attributes, dendritic glucans have been widely applied in the food, pharmaceutical, biomedical, cosmetic, and chemical industries. For instance, they have been used as delivery systems, adsorbents, tissue engineering scaffolds, biosensors, and bioelectronic components. This article reviews progress in the design, synthesis, and application of dendritic glucans over the past several decades.

The use of RNA-based treatments in the field of cancer immunotherapy

Over the past several decades, mRNA vaccines have evolved from a theoretical concept to a clinical reality. These vaccines offer several advantages over traditional vaccine techniques, including their high potency, rapid development, low-cost manufacturing, and safe administration. However, until recently, concerns over the instability and inefficient distribution of mRNA in vivo have limited their utility. Fortunately, recent technological advancements have mostly resolved these concerns, resulting in the development of numerous mRNA vaccination platforms for infectious diseases and various types of cancer. These platforms have shown promising outcomes in both animal models and humans. This study highlights the potential of mRNA vaccines as a promising alternative approach to conventional vaccine techniques and cancer treatment. This review article aims to provide a thorough and detailed examination of mRNA vaccines, including their mechanisms of action and potential applications in cancer immunotherapy. Additionally, the article will analyze the current state of mRNA vaccine technology and highlight future directions for the development and implementation of this promising vaccine platform as a mainstream therapeutic option. The review will also discuss potential challenges and limitations of mRNA vaccines, such as their stability and in vivo distribution, and suggest ways to overcome these issues. By providing a comprehensive overview and critical analysis of mRNA vaccines, this review aims to contribute to the advancement of this innovative approach to cancer treatment.

Recent Advances in Nano-Drug Delivery Systems for the Treatment of Diabetic Wound Healing

Diabetes mellitus (DM) induced wound healing impairment remains a serious health problem and burden on the clinical obligation for high amputation rates. Based on the features of wound microenvironment, biomaterials loading specific drugs can benefit diabetic wound treatment. Drug delivery systems (DDSs) can carry diverse functional substances to the wound site. Nano-drug delivery systems (NDDSs), benefiting from their features related to nano size, overcome limitations of conventional DDSs application and are considered as a developing process in the wound treatment field. Recently, a number of finely designed nanocarriers efficiently loading various substances (bioactive and non-bioactive factors) have emerged to circumvent constraints faced by traditional DDSs. This review describes various recent advances of nano-drug delivery systems involved in mitigating diabetes mellitus-based non-healing wounds.

Enhancing the antitumor immunosurveillance of PD-L1-targeted gene therapy for metastatic melanoma using cationized Panax Notoginseng polysaccharide

Improved curative effects with reduced toxicity has always been the ultimate goal of gene delivery vectors for tumor immunotherapy. Panax notoginseng polysaccharide (PNP), a natural plant-derived macromolecule, not only has antitumor immune activity but also has the typical structural characteristics useful for gene delivery. In this work, positively charged polyethyleneimine (PEI) was directly grafted to the backbone of PNP to induced its charge reversal and generate a functional gene vector (PNP-PEI). Moreover, a short hairpin RNA targeting the programmed death-ligand 1 (PD-L1) was loaded into PNP-PEI to generate a potentially therapeutic nanoparticle (PNP-PEI/shPD-L1). In vitro and in vivo experiments demonstrated that PNP-PEI could efficiently carry the therapeutic shPD-L1 into tumor cells and that PNP-PEI/shPD-L1 could significantly inhibit the expression of PD-L1 and growth of B16-F10 cells. Noteworthily, treatment with PNP-PEI reversed the phenotype of macrophages from M2 to M1 subtype and promoted dendritic cell maturation, which encouraged the host immunity and enhanced the therapeutic antitumor effects. In summary, this study describes a PNP-based gene delivery vector and highlights the beneficial immunopotentiating therapeutic outcomes of PNP-PEI for tumor immunotherapy.

Macrophages as a therapeutic target to promote diabetic wound healing

It is well‏ ‏established that macrophages are key regulators of wound healing, displaying impressive plasticity and an evolving phenotype, from an aggressive pro-inflammatory or "M1" phenotype to a pro-healing or "M2" phenotype, depending on the wound healing stage, to ensure proper healing. Because dysregulated macrophage responses have been linked to impaired healing of diabetic wounds, macrophages are being considered as a therapeutic target for improved wound healing. In this review, we first discuss the role of macrophages in a normal skin wound healing process and discuss the aberrations that occur in macrophages under diabetic conditions. Next we provide an overview of recent macrophage-based therapeutic approaches, including delivery of ex-vivo-activated macrophages and delivery of pharmacological strategies aimed at eliminating or re-educating local skin macrophages. In particular, we focus on strategies to silence key regulator genes to repolarize wound macrophages to the M2 phenotype, and we provide a discussion of their potential future clinical translation.

Nucleic acid-based therapeutics for dermal wound healing

Non-healing wounds have long been the subject of scientific and clinical investigations. Despite breakthroughs in understanding the biology of delayed wound healing, only limited advances have been made in properly treating wounds. Recently, research into nucleic acids (NAs) such as small-interfering RNA (siRNA), microRNA (miRNA), plasmid DNA (pDNA), aptamers, and antisense oligonucleotides (ASOs) has resulted in the development of a latest therapeutic strategy for wound healing. In this regard, dendrimers, scaffolds, lipid nanoparticles, polymeric nanoparticles, hydrogels, and metal nanoparticles have all been explored as NA delivery techniques. However, the translational possibility of NA remains a substantial barrier. As a result, different NAs must be identified, and their distribution method must be optimized. This review explores the role of NA-based therapeutics in various stages of wound healing and provides an update on the most recent findings in the development of NA-based nanomedicine and biomaterials, which may offer the potential for the invention of novel therapies for this long-term condition. Further, the challenges and potential for miRNA-based techniques to be translated into clinical applications are also highlighted.

Nanobiotechnology: Applications in Chronic Wound Healing

Wounds occur when skin integrity is broken and the skin is damaged. With progressive changes in the disease spectrum, the acute wounds caused by mechanical trauma have been become less common, while chronic wounds triggered with aging, diabetes and infection have become more frequent. Chronic wounds now affect more than 6 million people in the United States, amounting to 10 billion dollars in annual expenditure. However, the treatment of chronic wounds is associated with numerous challenges. Traditional remedies for chronic wounds include skin grafting, flap transplantation, negative-pressure wound therapy, and gauze dressing, all of which can cause tissue damage or activity limitations. Nanobiotechnology — which comprises a diverse array of technologies derived from engineering, chemistry, and biology — is now being applied in biomedical practice. Here, we review the design, application, and clinical trials for nanotechnology-based therapies for chronic wound healing, highlighting the clinical potential of nanobiotechnology in such treatments. By summarizing previous nanobiotechnology studies, we lay the foundation for future wound care via a nanotech-based multifunctional smart system.

The Emerging Role of Immune Cells and Targeted Therapeutic Strategies in Diabetic Wounds Healing

Poor wound healing in individuals with diabetes has long plagued clinicians, and immune cells play key roles in the inflammation, proliferation and remodeling that occur in wound healing. When skin integrity is damaged, immune cells migrate to the wound bed through the actions of chemokines and jointly restore tissue homeostasis and barrier function by exerting their respective biological functions. An imbalance of immune cells often leads to ineffective and disordered inflammatory responses. Due to the maladjusted microenvironment, the wound is unable to smoothly transition to the proliferation and remodeling stage, causing it to develop into a chronic refractory wound. However, chronic refractory wounds consistently lead to negative outcomes, such as long treatment cycles, high hospitalization rates, high medical costs, high disability rates, high mortality rates, and many adverse consequences. Therefore, strategies that promote the rational distribution and coordinated development of immune cells during wound healing are very important for the treatment of diabetic wounds (DW). Here, we explored the following aspects by performing a literature review: 1) the current situation of DW and an introduction to the biological functions of immune cells; 2) the role of immune cells in DW; and 3) existing (or undeveloped) therapies targeting immune cells to promote wound healing to provide new ideas for basic research, clinical treatment and nursing of DW.

Pre-Clinical and Clinical Applications of Small Interfering RNAs (siRNA) and Co-Delivery Systems for Pancreatic Cancer Therapy

Pancreatic cancer (PC) is one of the leading causes of death and is the fourth most malignant tumor in men. The epigenetic and genetic alterations appear to be responsible for development of PC. Small interfering RNA (siRNA) is a powerful genetic tool that can bind to its target and reduce expression level of a specific gene. The various critical genes involved in PC progression can be effectively targeted using diverse siRNAs. Moreover, siRNAs can enhance efficacy of chemotherapy and radiotherapy in inhibiting PC progression. However, siRNAs suffer from different off target effects and their degradation by enzymes in serum can diminish their potential in gene silencing. Loading siRNAs on nanoparticles can effectively protect them against degradation and can inhibit off target actions by facilitating targeted delivery. This can lead to enhanced efficacy of siRNAs in PC therapy. Moreover, different kinds of nanoparticles such as polymeric nanoparticles, lipid nanoparticles and metal nanostructures have been applied for optimal delivery of siRNAs that are discussed in this article. This review also reveals that how naked siRNAs and their delivery systems can be exploited in treatment of PC and as siRNAs are currently being applied in clinical trials, significant progress can be made by translating the current findings into the clinical settings.

Development of purified glycogen derivatives as siRNA nanovectors

Purified Glycogen (PG) is a highly hyper branched carbohydrate, characterized by high water solubility and very moderate increase in viscosity. The dendrimeric structure of PG, appropriately functionalized, makes it an alternative to current synthetic gene delivery agents. The present study explores the preparation of purified glycogen polycationic derivatives (PGPDs), developed and characterized starting from a single step reaction between PG and N,N-dialkylamino alkyl halides. Subsequently PGPDs were used for the complexation of a model siRNA nucleic acid, a transfection reagent siRNA and a fluorescein-labelled dsRNA oligomer. PGPDs-siRNA complexes were fully characterized by agarose gel electrophoresis and their efficacy was assessed by both confocal microscopy and transfection assays on breast and renal cancer cells. Results proved that PGPDs-siRNA complexes were efficient and not cytotoxic, maintaining their spherical and dendrimeric structure and, particularly, were able to effectively transfect the target cells by releasing the siRNA.

Current knowledge of immunomodulation strategies for chronic skin wound repair

In orchestrating the wound healing process, the immune system plays a critical role. Hence, controlling the immune system to repair skin defects is an attractive approach. The highly complex immune system includes the coordinated actions of several immune cells, which can produce various inflammatory and antiinflammatory cytokines and affect the healing of skin wounds. This process can be optimized using biomaterials, bioactive molecules, and cell delivery. The present review discusses various immunomodulation strategies for supporting the healing of chronic wounds. In this regard, following the evolution of the immune system and its role in the wound healing mechanism, the interaction between the extracellular mechanism and immune cells for acceleration wound healing will be firstly investigated. Consequently, the immune-based chronic wounds will be briefly examined and the mechanism of progression, and conventional methods of their treatment are evaluated. In the following, various biomaterials-based immunomodulation strategies are introduced to stimulate and control the immune system to treat and regenerate skin defects. Other effective methods of controlling the immune system in wound healing which is the release of bioactive agents (such as antiinflammatory, antigens, and immunomodulators) and stem cell therapy at the site of injury are reviewed.

Sustained delivery of MMP-9 siRNA via thermosensitive hydrogel accelerates diabetic wound healing

Excessive expression of matrix metalloproteinase 9 (MMP-9) impedes healing of diabetic chronic wounds, thus wound dressing that could effectively inhibit the expression of MMP-9 offers significant clinical translation for diabetic wound healing. Herein, a hybrid hydrogel dressing was developed for localized and sustained delivery of MMP-9 siRNA (siMMP-9). siMMP-9 was complexed with Gly-TETA (GT), the GT/siMMP9 complex was then loaded into a thermosensitive hydrogel based on Pluronic F-127 (PF) and methylcellulose (MC). In vitro, this hybrid hydrogel dressing exhibited negligible cytotoxicity, prolonged the release of GT/siMMP-9 for up to 7 days, and significantly reduced MMP-9 expression. In vivo assessment in diabetic rats demonstrated that hydrogel provided localized and sustained delivery via the thermosensitive controlled release of entrapped GT/siMMP-9 into wound tissues for 7 days, resulting in dramatic MMP-9 silencing which significantly improved diabetic wound closure. This hybrid hydrogel dressing exhibited excellent biocompatibility, with no observed systemic toxicity in rats. Taken together, the hybrid hydrogel dressing may constitute an effective and biocompatible means of enhancing diabetic wound healing through effective silencing of the MMP-9 gene, and this hydrogel delivery system also offers a platform for in vivo delivery of siRNA for the treatment of other diseases.