Therapeutic Effects of Self-Assembled Tetrahedral Framework Nucleic Acids on Liver Regeneration in Acute Liver Failure

In Vivo Interactions of Nucleic Acid Nanostructures With Cells

Nucleic acid nanostructures, derived from the assembly of nucleic acid building blocks (e.g., plasmids and oligonucleotides), are important intracellular carriers of therapeutic cargoes widely utilized in preclinical nanomedicine applications, yet their clinical translation remains scarce. In the era of "translational nucleic acid nanotechnology", a deeper mechanistic understanding of the interactions of nucleic acid nanostructures with cells in vivo will guide the development of more efficacious nanomedicines. This review showcases the recent progress in dissecting the in vivo interactions of four key types of nucleic acid nanostructures (i.e., tile-based, origami, spherical nucleic acid, and nucleic acid nanogel) with cells in rodents over the past five years. Emphasis lies on the cellular-level distribution of nucleic acid nanostructures in various organs and tissues and the cellular responses induced by their cellular entry. Next, in the spirit of preclinical translation, this review features the latest interactions of nucleic acid nanostructures with cells in large animals and humans. Finally, the review offers directions for studying the interactions of nucleic acid nanostructures with cells from both materials and biology perspectives and concludes with some regulatory updates.

Enzyme-Responsive Nanoparachute for Targeted miRNA Delivery: A Protective Strategy Against Acute Liver and Kidney Injury

MicroRNA (miRNA)-based therapy holds significant potential; however, its structural limitations pose a challenge to the full exploitation of its biomedical functionality. Framework nucleic acids are promising owing to their transportability, biocompatibility, and functional editability. MiRNA-125 is embedded into a nucleic acid framework to create an enzyme-responsive nanoparachute (NP), enhancing the miRNA loading capacity while preserving the attributes of small-scale framework nucleic acids and circumventing the uncertainty related to RNA exposure in conventional loading methods. An enzyme-sensitive sequence is designed in NP as a bioswitchable apparatus for cargo miRNAs release. NP is compared with conventional delivery modes and delivery vehicles, confirming its excellent transportability and sustained release properties. Moreover, NP confers good enzyme and serum resistance to the cargo miRNAs. Simultaneously, it can easily deliver miRNA-125 to liver and kidney lesions owing to its passive targeting properties. This allows for Keap1/Nrf2 pathway regulation and p53 protein targeting in the affected tissues. Additionally, NP negatively regulates the expression of Bax and Caspase-3. These combined actions help to inhibit oxidation, prevent cell cycle arrest, and reduce the apoptosis of liver and kidney cells. Consequently, this strategy offers a potential treatment for acute liver and kidney injury.

Unveiling the Potential of Tetrahedral DNA Frameworks in Clinical Medicine: Mechanisms, Advances, and Future Perspectives

As deoxyribonucleic acis (DNA) nanotechnology advances, DNA, a fundamental biological macromolecule, has been employed to treat various clinical diseases. Among the advancements in this field, tetrahedral frameworks nucleic acids (tFNAs) have gained significant attention due to their straightforward design, structural simplicity, low cost, and high yield since their introduction by Turberfield in the early 2000s. Due to its stable spatial structure, tFNAs can resist the impact of innate immune responses on DNA and nuclease activity. Meanwhile, structural programmability of tFNAs allows for the development of static tFNA-based nanomaterials through the engineering of functional oligonucleotides or therapeutic molecules and dynamic tFNAs through the attachment of stimuli-responsive DNA apparatuses. This review first summarizes the key merits of tFNAs, including natural biocompatibility, biodegradability, structural stability, unparalleled programmability, functional diversity, and efficient cellular internalization. Based on these strengths, this review comprehensively analyzes applications of tFNAs in different clinical settings, including orthopedics, stomatology, urinary system diseases, liver-related diseases, tumors, infection, neural system diseases, ophthalmic diseases, and immunoprophylaxis. We also discuss the limitations of tFNAs and the challenges encountered in preclinical studies. This review provides new perspectives for future research and valuable guidance for researchers working in this field.

Tetrahedral Framework Nucleic Acids Delivery of Pirfenidone for Anti-Inflammatory and Antioxidative Effects to Treat Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic and irreversible lung disease, and developing an effective treatment remains a challenge. The limited therapeutic options are primarily delivered by the oral route, among which pirfenidone (PFD) improves pulmonary dysfunction and patient quality of life. However, its high dose and severe side effects (dyspepsia and systemic photosensitivity) limit its clinical value. Intratracheal aerosolization is an excellent alternative method for treating lung diseases because it increases the concentration of the drug needed to reach the focal site. Tetrahedral framework nucleic acid (tFNA) is a drug delivery system with exceptional delivery capabilities. Therefore, we synthesized a PFD-tFNA (Pt) complex using tFNA as the delivery vehicle and achieved quantitative nebulized drug delivery to the lungs via micronebulizer for lung fibrosis treatment. In vivo, Pt exhibited excellent immunomodulatory capacity and antioxidant effects. Furthermore, Pt reduced mortality, gradually restored body weight and improved lung tissue structure. Similarly, Pt also exhibited superior fibrosis inhibition in an in vitro fibrosis model, as shown by the suppression of excessive fibroblast activation and epithelial-mesenchymal transition (EMT) in epithelial cells exposed to TGF-β1. Conclusively, Pt, a complex with tFNA as a transport system, could enrich the therapeutic regimen for IPF via intratracheal aerosolization inhalation.

Liver regeneration after injury: Mechanisms, cellular interactions and therapeutic innovations

The liver possesses a distinctive capacity for regeneration within the human body. Under normal circumstances, liver cells replicate themselves to maintain liver function. Compensatory replication of healthy hepatocytes is sufficient for the regeneration after acute liver injuries. In the late stage of chronic liver damage, a large number of hepatocytes die and hepatocyte replication is blocked. Liver regeneration has more complex mechanisms, such as the transdifferentiation between cell types or hepatic progenitor cells mediated. Dysregulation of liver regeneration causes severe chronic liver disease. Gaining a more comprehensive understanding of liver regeneration mechanisms would facilitate the advancement of efficient therapeutic approaches. This review provides an overview of the signalling pathways linked to different aspects of liver regeneration in various liver diseases. Moreover, new knowledge on cellular interactions during the regenerative process is also presented. Finally, this paper explores the potential applications of new technologies, such as nanotechnology, stem cell transplantation and organoids, in liver regeneration after injury, offering fresh perspectives on treating liver disease.

Tetrahedral DNA-Based Functional MicroRNA-21 Delivery System: Application to Corneal Epithelial Wound Healing

Corneal injury occurs frequently which may lead to serious visual impairment. Rapid and efficient re-epithelialization after corneal epithelial injury is the key issue for maintaining corneal homeostasis. Among various treatment strategies, microRNA (miR)-based therapy shows great potential. However, structural limitations of miRNAs hinder its biomedical functionality. Nucleic acid nanotechnology is an appealing candidate for gene delivery because of its flexible modification and excellent biocompatibility. Herein, modified 3D tetrahedral framework nucleic acids (tFNAs) utilized as gene carriers for miR-21 delivery are constructed. TFNAs-miR-21 (T-21) shows great enzymatic resistance in extracellular environment and payload delivery into human corneal epithelial cells (HCECs) via clathrin-mediated endocytosis. T-21 facilitates proliferation and migration in HCECs via activating PI3K/AKT and ERK1/2 signaling pathways in vitro. In vivo studies, T-21 can be internalized by corneal epithelium in mice. In the mice corneal scratch model, T-21 ophthalmic solutions used as eye drops show no apparent side effects on the ocular surface histologically and exert great potential in accelerating corneal wound healing. These findings demonstrate that modified tFNAs are promising candidates for miRNA delivery for corneal wound healing. The convenient administration and great biocompatibility of tetrahedral DNA nanoparticles highlight its potential as gene transporter in solving ocular problems.

Multimodal Tetrahedral DNA Nanoplatform for Surprisingly Rapid and Significant Treatment of Acute Liver Failure

Acute liver failure (ALF) is a life-threatening disease associated with the rapid development of inflammatory storms, level elevation of reactive oxygen species (ROS), and hepatocyte necrosis, which results in high short-term mortality. Except for liver transplantation, no effective strategies are available for ALF therapy due to the rapid disease progression and narrow window of therapeutic time. Therefore, there is an urgent demand to explore the fast and effective modalities for ALF treatment. Herein, a multifunctional tetrahedral DNA nanoplatform (TDN) is constructed by incorporating tumor necrosis factor-α siRNA (siTNF-α) through DNA hybridization and antioxidant manganese porphyrin (MnP4) via π-π stacking interaction with G-quadruplex (G4) for surprisingly rapid and significant ALF therapy. TDN-siTNF-α/-G4-MnP4 silences TNF-α of macrophages by siTNF-α and polarizes them to the anti-inflammatory M2 phenotype, providing appropriate microenvironments for hepatocyte viability. Additionally, TDN-siTNF-α/-G4-MnP4 scavenges intracellular ROS by MnP4, protecting hepatocytes from oxidative-stress-associated cell death. Furthermore, TDN itself promotes hepatocyte proliferation by modulating the cell cycle. TDN-siTNF-α/-G4-MnP4 shows almost complete liver accumulation after intravenous injection and exhibits excellent therapeutic efficacy of ALF within 2 h. The multifunctional DNA nanoformulation provides an effective strategy for rapid ALF therapy, expanding its application for innovative treatments of liver diseases.

Recent advances in molecular mechanisms of skin wound healing and its treatments

The skin, being a multifaceted organ, performs a pivotal function in the complicated wound-healing procedure, which encompasses the triggering of several cellular entities and signaling cascades. Aberrations in the typical healing process of wounds may result in atypical scar development and the establishment of a persistent condition, rendering patients more vulnerable to infections. Chronic burns and wounds have a detrimental effect on the overall quality of life of patients, resulting in higher levels of physical discomfort and socio-economic complexities. The occurrence and frequency of prolonged wounds are on the rise as a result of aging people, hence contributing to escalated expenditures within the healthcare system. The clinical evaluation and treatment of chronic wounds continue to pose challenges despite the advancement of different therapeutic approaches. This is mainly owing to the prolonged treatment duration and intricate processes involved in wound healing. Many conventional methods, such as the administration of growth factors, the use of wound dressings, and the application of skin grafts, are used to ease the process of wound healing across diverse wound types. Nevertheless, these therapeutic approaches may only be practical for some wounds, highlighting the need to advance alternative treatment modalities. Novel wound care technologies, such as nanotherapeutics, stem cell treatment, and 3D bioprinting, aim to improve therapeutic efficacy, prioritize skin regeneration, and minimize adverse effects. This review provides an updated overview of recent advancements in chronic wound healing and therapeutic management using innovative approaches.

A Mitochondrial Nanoguard Modulates Redox Homeostasis and Bioenergy Metabolism in Diabetic Peripheral Neuropathy

As a major late complication of diabetes, diabetic peripheral neuropathy (DPN) is the primary reason for amputation. Nevertheless, there are no wonder drugs available. Regulating dysfunctional mitochondria is a key therapeutic target for DPN. Resveratrol (RSV) is widely proven to guard mitochondria, yet the unsatisfactory bioavailability restricts its clinical application. Tetrahedral framework nucleic acids (tFNAs) are promising carriers due to their excellent cell entrance efficiency, biological safety, and structure editability. Here, RSV was intercalated into tFNAs to form the tFNAs-RSV complexes. tFNAs-RSV achieved enhanced stability, bioavailability, and biocompatibility compared with tFNAs and RSV alone. With its treatment, reactive oxygen species (ROS) production was minimized and reductases were activated in an in vitro model of DPN. Besides, respiratory function and adenosine triphosphate (ATP) production were enhanced. tFNAs-RSV also exhibited favorable therapeutic effects on sensory dysfunction, neurovascular deterioration, demyelination, and neuroapoptosis in DPN mice. Metabolomics analysis revealed that redox regulation and energy metabolism were two principal mechanisms that were impacted during the process. Comprehensive inspections indicated that tFNAs-RSV inhibited nitrosation and oxidation and activated reductase and respiratory chain. In sum, tFNAs-RSV served as a mitochondrial nanoguard (mito-guard), representing a viable drilling target for clinical drug development of DPN.

MicroRNA-122-functionalized DNA tetrahedron stimulate hepatic differentiation of human mesenchymal stem cells for acute liver failure therapy

As the most abundant liver-specific microRNA, microRNA-122 (miR122) played a crucial role in the differentiation of stem cells into hepatocytes. However, highly efficient miR122 delivery still confronts challenges including poor cellular uptake and easy biodegradation. Herein, we for the first time demonstrated that the tetrahedral DNA (TDN) nanoplatform had great potential in inducing the differentiation of human mesenchymal stem cells (hMSCs) into functional hepatocyte-like cells (HLCs) by transferring the liver-specific miR122 to hMSCs efficiently without any extrinsic factors. As compared with miR122, miR122-functionalized TDN (TDN-miR122) could significantly up-regulate the protein expression levels of mature hepatocyte markers and hepatocyte-specific marker genes in hMSCs, indicating that TDN-miR122 could particularly activate the hepatocyte-specific properties of hMSCs for developing cell-based therapies in vitro. The transcriptomic analysis further indicated the potential mechanism that TDN-miR122 assisted hMSCs differentiated into functional HLCs. The TDN-miR122-hMSCs exhibited hepatic cell morphology phenotype, significantly up-regulated specific hepatocyte genes and hepatic biofunctions in comparison with the undifferentiated MSCs. Preclinical in vivo transplantation appeared that TDN-miR122-hMSCs in combination with or without TDN could efficiently rescue acute liver failure injury through hepatocyte function supplement, anti-apoptosis, cellular proliferation promotion, and anti-inflammatory. Collectively, our findings may provide a new and facile approach for hepatic differentiation of hMSCs for acute liver failure therapy. Further large animal model explorations are needed to study their potential in clinical translation in the future.

Recent progress and application of the tetrahedral framework nucleic acid materials on drug delivery

INTRODUCTION

The application of DNA framework nucleic acid materials in the biomedical field has witnessed continual expansion. Among them, tetrahedral framework nucleic acids (tFNAs) have gained significant traction as the foremost biological vectors due to their superior attributes of editability, low immunogenicity, biocompatibility, and biodegradability. tFNAs have demonstrated promising results in numerous in vitro and in vivo applications.

AREAS COVERED

This review summarizes the latest research on tFNAs in drug delivery, including a discussion of the advantages of tFNAs in regulating biological behaviors, and highlights the updated development and advantageous applications of tFNAs-based nanostructures from static design to dynamically responsive design.

EXPERT OPINION

tFNAs possess distinct biological regulatory attributes and can be taken up by cells without the requirement of transfection, differentiating them from other biological vectors. tFNAs can be easily physically/chemically modified and seamlessly incorporated with other functional systems. The static design of the tFNAs-based drug delivery system makes it versatile, reproducible, and predictable. Further use of the dynamic response mechanism of DNA to external stimuli makes tFNAs-based drug delivery more effective and specific, improving the uptake and utilization of the payload by the intended target. Dynamic targeting is poised to become the future primary approach for drug delivery.

Dendrimer-like Hierarchical Framework Nucleic Acid for Real-Time Imaging of Intracellular Trafficking

Framework nucleic acids (FNAs) represent a new type of DNA-based nanomaterials and possess great potentials in biosensing, bioimaging, and molecular delivery. Hierarchical DNA nanostructures that consist of multiple FNA monomers increase the capacity for drug delivery and multifunctional modification. However, there are relatively few studies devoted to the behavior and regulation of hierarchical FNAs in living cells, impeding their further applications. Herein, we constructed a dendritic nanostructure with five tetrahedral DNA nanocages and characterized the real-time internalization, inter-organelle trafficking, and exocytosis in living mammalian cells. In comparison to FNA monomers, FNA dendrimers exhibit increased endocytosis and prolonged cellular retention. Single-particle tracking on hundreds of FNA dendrimers exhibits no interference on the mobility or kinetics of subcellular organelles, implying that FNAs as well as their higher-order derivatives are ideal intracellular imaging probes and nanocarriers. Our study validates the suitability and superiority of hierarchical DNA nanostructures as high-valency scaffolds for biomedical applications.

Framework Nucleic Acids as Blood-Retinal-Barrier-Penetrable Nanocarrier for Periocular Administration

Designing an ocular drugs delivery system that can permeate the outer blood-retinal barrier (oBRB) is crucial for the microinvasive or noninvasive treatment of ocular fundus diseases. However, due to the lack of a nanocarrier that can maintain structure and composition at the oBRB, only intravitreal injection at the eyeball can deliver therapeutics directly to the ocular fundus via paracellular and intercellular routes, despite the intraocular operations risks. Here, we demonstrated tetrahedral framework nucleic acids (tFNAs) can penetrate the oBRB and deliver therapeutic nucleic acids to the retina of the rat eye in vivo following subconjunctival injection. We also discovered that tFNAs were transported via a paracellular route across the intercellular tight junctions at the oBRB. The histology analysis for ocular layers indicated that individual and aptamer/doxorubicin-loaded tFNAs penetrated all layers of the posterior segment of the eyeball to reach the innermost retina and persisted for over 3 days with minimal systemic biodistribution. We expect that the programmability and penetrability of tFNAs will provide a promising method for drug delivery across oBRB and long-term sustenance at the target site via periocular administration to various tissues.

Antifibrotic Effects of Tetrahedral Framework Nucleic Acids by Inhibiting Macrophage Polarization and Macrophage-Myofibroblast Transition in Bladder Remodeling

Bladder outlet obstruction (BOO) is a prevalent condition arising from urethral stricture, posterior urethral valves, and benign prostatic hyperplasia. Long-term obstruction can lead to bladder remodeling, which is characterized by inflammatory cell infiltration, detrusor hypertrophy, and fibrosis. Until now, there are no efficacious therapeutic options for BOO-induced remodeling. Tetrahedral framework nucleic acids (tFNAs) are a type of novel 3D DNA nanomaterials that possess excellent antifibrotic effects. Here, to determine the treatment effects of tFNAs on BOO-induced remodeling is aimed. Four single-strand DNAs are self-assembled to form tetrahedral framework DNA nanostructures, and the antifibrotic effects of tFNAs are investigated in an in vivo BOO animal model and an in vitro transforming growth factor beta1 (TGF-β1)-induced fibrosis model. The results demonstrated that tFNAs could ameliorate BOO-induced bladder fibrosis and dysfunction by inhibiting M2 macrophage polarization and the macrophage-myofibroblast transition (MMT) process. Furthermore, tFNAs regulate M2 polarization and the MMT process by deactivating the signal transducer and activator of transcription (Stat) and TGF-β1/small mothers against decapentaplegic (Smad) pathways, respectively. This is the first study to reveal that tFNAs might be a promising nanomaterial for the treatment of BOO-induced remodeling.

Albumin-Coated Framework Nucleic Acids as Bionic Delivery System for Triple-Negative Breast Cancer Therapy

Triple-negative breast cancer (TNBC) is a subtype of breast cancer, and it has aggressive and more frequent tissue metastases than other breast cancer subtypes. Because the proliferation of TNBC tumor cells does not depend on estrogen receptor (ER), progesterone receptor (PR), and Erb-B2 receptor tyrosine kinase 2 (HER2) and lacks accurate drug targets, conventional chemotherapy is challenging to be effective, and adverse reactions are severe. At present, the treatment strategy for TNBC generally depends on a combination of surgery, radiotherapy, and chemotherapy. Conventional administration methods have minimal effects on TNBC and cause severe damage to normal tissues. Therefore, it is an urgent task to develop an efficient and practical way of drug delivery and open up a new horizon of targeted therapy for TNBC. In our work, bovine serum albumin (BSA) acted as the protective film to prolong the circulation time of the tetrahedral framework nucleic acid (tFNA) delivery system and resist immune clearance in vivo. tFNA was used as a carrier loaded with DOX and AS1411 aptamers for the targeted treatment of triple-negative breast cancer. Compared with existing approaches, this optimized system exhibits stronger tumor-targeting so that tFNAs can be more concentrated around the tumor tissue, reducing DOX toxicity to other organs. This bionic delivery system exhibited effective tumor growth inhibition in the TNBC mice model, offering the clinical potential to promote the treatment of TNBC with great potential for clinical translation.

Pyroptosis and inflammasomes in diabetic wound healing

Diabetic wound is one of the complications of diabetes and is not easy to heal. It often evolves into chronic ulcers, and severe patients will face amputation. Compared with normal wounds, diabetic wounds have an increased proportion of pro-inflammatory cytokines that are detrimental to the normal healing response. The burden of this disease on patients and healthcare providers is overwhelming, and practical solutions for managing and treating diabetic wounds are urgently needed. Pyroptosis, an inflammatory type of programmed cell death, is usually triggered by the inflammasome. The pyroptosis-driven cell death process is primarily mediated by the traditional signaling pathway caused by caspase -1 and the non-classical signaling pathways induced by caspase -4/5/11. Growing evidence that pyroptosis promotes diabetic complications, including diabetic wounds. In addition, inflammation is thought to be detrimental to wound healing. It is worth noting that the activation of the NLRP3 inflammasome plays a crucial role in the recovery of diabetic wounds. This review has described the mechanisms of pyroptosis-related signaling pathways and their impact on diabetic wounds. It has discussed new theories and approaches to promote diabetic wound healing, as well as some potential compounds targeting pyroptosis and inflammasome signaling pathways that could be new approaches to treating diabetic wounds.