Biological Effect of Differently Sized Tetrahedral Framework Nucleic Acids: Endocytosis, Proliferation, Migration, and Biodistribution

A bioswitchable delivery system for microRNA therapeutics based on a tetrahedral DNA nanostructure

As microRNAs (miRNA) regulate almost all physiopathological activities in the human body, miRNA therapeutics that deliver miRNA regulators have attracted considerable attention in the field of nucleic acid drug development. The use of tetrahedral DNA nanostructures to deliver miRNA regulators is promising because of their simple fabrication, enhanced cell entry, effective tissue penetration, biocompatibility and functional editability. This protocol extension builds on our previous protocol for the use of tetrahedral DNA nanostructures and was designed to establish an updated bioswitchable delivery system (BDS) for achieving controlled cargo loading and release. A ribonuclease H-sensitive sequence is designed as a bioswitchable apparatus for the targeted release of the miRNA regulator. The functional sequence of the miRNA regulator and minimal secondary structure formation tendency during annealing are two key points in cargo design. We provide two BDS design strategies; BDS-A comprises an intact DNA tetrahedron with the RNA cargo hanging outside, offering the merits of lower cost, simplicity, and more direct structural design. In the BDS-B design, the RNA regulators are embedded into the DNA tetrahedron, which is beneficial for dermal tissue permeation applications. Following sequence design in Oligo 7 and Tiamat, the BDS assembly is completed and then ribonuclease H achieves controlled release of the miRNA regulator by triggering the bioswitchable apparatus. This is verified via polyacrylamide and agarose gel electrophoresis or fluorophore modifications. Both BDSs show promising cellular membrane permeability, tissue permeability and target inhibition in vitro and in vivo. The assembly and characterization of the BDS can be completed in 4 d, and the validation time for biostability and biological applications will depend on the specific use.

Adoption of a Tetrahedral DNA Nanostructure as a Multifunctional Biomaterial for Drug Delivery

DNA nanostructures have been widely researched in recent years as emerging biomedical materials for drug delivery, biosensing, and cancer therapy, in addition to their hereditary function. Multiple precisely designed single-strand DNAs can be fabricated into complex, three-dimensional DNA nanostructures through a simple self-assembly process. Among all of the synthetic DNA nanostructures, tetrahedral DNA nanostructures (TDNs) stand out as the most promising biomedical nanomaterial. TDNs possess the merits of structural stability, cell membrane permeability, and natural biocompatibility due to their compact structures and DNA origin. In addition to their inherent advantages, TDNs were shown to have great potential in delivering therapeutic agents through multiple functional modifications. As a multifunctional material, TDNs have enabled innovative pharmaceutical applications, including antimicrobial therapy, anticancer treatment, immune modulation, and cartilage regeneration. Given the rapid development of TDNs in the biomedical field, it is critical to understand how to successfully produce and fine-tune the properties of TDNs for specific therapeutic needs and clinical translation. This article provides insights into the synthesis and functionalization of TDNs and summarizes the approaches for TDN-based therapeutics delivery as well as their broad applications in the field of pharmaceutics and nanomedicine, challenges, and future directions.

Self-Assembly of Ultrasmall 3D Architectures of (l)-Acyclic Threoninol Nucleic Acids with High Thermal and Serum Stability

The primary challenge of implementing DNA nanostructures in biomedical applications lies in their vulnerability to nuclease degradation and variations in ionic strength. Furthermore, the size minimization of DNA and RNA nanostructures is limited by the stability of the DNA and RNA duplexes. This study presents a solution to these problems through the use of acyclic (l)-threoninol nucleic acid (aTNA), an artificial acyclic nucleic acid, which offers enhanced resilience under physiological conditions. The high stability of homo aTNA duplexes enables the design of durable nanostructures with dimensions below 5 nm, previously unattainable due to the inherent instability of DNA structures. The assembly of a stable aTNA-based 3D cube and pyramid that involves an i-motif formation is demonstrated. In particular, the cube outperforms its DNA-based counterparts in terms of stability. We furthermore demonstrate the successful attachment of a nanobody to the aTNA cube using the favorable triplex formation of aTNA with ssDNA. The selective in vitro binding capability to human epidermal growth factor receptor 2 is demonstrated. The presented research presents the use of aTNA for the creation of smaller durable nanostructures for future medical applications. It also introduces a new method for attaching payloads to these structures, enhancing their utility in targeted therapies.

Targeted delivery of CEBPA-saRNA for the treatment of pancreatic ductal adenocarcinoma by transferrin receptor aptamer decorated tetrahedral framework nucleic acid

Pancreatic cancer, predominantly pancreatic ductal adenocarcinoma (PDAC), remains a highly lethal malignancy with limited therapeutic options and a dismal prognosis. By targeting the underlying molecular abnormalities responsible for PDAC development and progression, gene therapy offers a promising strategy to overcome the challenges posed by conventional radiotherapy and chemotherapy. This study sought to explore the therapeutic potential of small activating RNAs (saRNAs) specifically targeting the CCAAT/enhancer-binding protein alpha (CEBPA) gene in PDAC. To overcome the challenges associated with saRNA delivery, tetrahedral framework nucleic acids (tFNAs) were rationally engineered as nanocarriers. These tFNAs were further functionalized with a truncated transferrin receptor aptamer (tTR14) to enhance targeting specificity for PDAC cells. The constructed tFNA-based saRNA formulation demonstrated exceptional stability, efficient saRNA release ability, substantial cellular uptake, biocompatibility, and nontoxicity. In vitro experiments revealed successful intracellular delivery of CEBPA-saRNA utilizing tTR14-decorated tFNA nanocarriers, resulting in significant activation of tumor suppressor genes, namely, CEBPA and its downstream effector P21, leading to notable inhibition of PDAC cell proliferation. Moreover, in a mouse model of PDAC, the tTR14-decorated tFNA-mediated delivery of CEBPA-saRNA effectively upregulated the expression of the CEBPA and P21 genes, consequently suppressing tumor growth. These compelling findings highlight the potential utility of saRNA delivered via a designed tFNA nanocarrier to induce the activation of tumor suppressor genes as an innovative therapeutic approach for PDAC.

Tetrahedral framework nucleic acids-based delivery of MicroRNA-22 inhibits pathological neovascularization and vaso-obliteration by regulating the Wnt pathway

The objective of this study was to investigate the effects and molecular mechanisms of tetrahedral framework nucleic acids-microRNA22 (tFNAs-miR22) on inhibiting pathological retinal neovascularization (RNV) and restoring physiological retinal vessels. A novel DNA nanocomplex (tFNAs-miR22) was synthesised by modifying microRNA-22 (miR22) through attachment onto tetrahedral frame nucleic acids (tFNAs), which possess diverse biological functions. Cell proliferation, wound healing, and tube formation were employed for in vitro assays to investigate the angiogenic function of cells. Oxygen-induced retinopathy (OIR) model was utilised to examine the effects of reducing pathological neovascularization (RNV) and inhibiting vascular occlusion in vivo. In vitro, tFNAs-miR22 demonstrated the ability to penetrate endothelial cells and effectively suppress cell proliferation, tube formation, and migration in a hypoxic environment. In vivo, tFNAs-miR22 exhibited promising results in reducing RNV and promoting the restoration of normal retinal blood vessels in OIR model through modulation of the Wnt pathway. This study provided a theoretical basis for the further understanding of RNV, and highlighted the innovative and potential of tFNAs-miR22 as a therapeutic option for ischemic retinal diseases.

Tetrahedral framework nucleic acids for improving wound healing

Wounds are one of the most common health issues, and the cost of wound care and healing has continued to increase over the past decade. In recent years, there has been growing interest in developing innovative strategies to enhance the efficacy of wound healing. Tetrahedral framework nucleic acids (tFNAs) have emerged as a promising tool for wound healing applications due to their unique structural and functional properties. Therefore, it is of great significance to summarize the applications of tFNAs for wound healing. This review article provides a comprehensive overview of the potential of tFNAs as a novel therapeutic approach for wound healing. In this review, we discuss the possible mechanisms of tFNAs in wound healing and highlight the role of tFNAs in modulating key processes involved in wound healing, such as cell proliferation and migration, angiogenesis, and tissue regeneration. The targeted delivery and controlled release capabilities of tFNAs offer advantages in terms of localized and sustained delivery of therapeutic agents to the wound site. In addition, the latest research progress on tFNAs in wound healing is systematically introduced. We also discuss the biocompatibility and biosafety of tFNAs, along with their potential applications and future directions for research. Finally, the current challenges and prospects of tFNAs are briefly discussed to promote wider applications.

Transcutaneous Immunotherapy for RNAi: A Cascade-Responsive Decomposable Nanocomplex Based on Polyphenol-Mediated Framework Nucleic Acid in Psoriasis

Skin is the first barrier against external threats, and skin immune dysfunction leads to multiple diseases. Psoriasis is an inflammatory, chronic, common, immune-related skin disease that affects more than 125 million people worldwide. RNA interference (RNAi) therapy is superior to traditional therapies, but rapid degradation and poor cell uptake are the greatest obstacles to its clinical transformation. The transdermal delivery of siRNA and controllable assembly/disassembly of nanodrug delivery systems can maximize the therapeutic effect. Tetrahedral framework nucleic acid (tFNA) is undoubtedly the best carrier for the transdermal transport of genes due to its excellent noninvasive transdermal effect and editability. The authors combine acid-responsive tannic acid (TA), RNase H-responsive sequences, siRNA, and tFNA into a novel transdermal RNAi drug with controllable assembly and disassembly: STT. STT has heightened resistance to enzyme, serum, and lysosomal degradation, and its size is similar to that of tFNA, enabling easy transdermal transport. After transdermal administration, STT can specifically silence nuclear factor kappa-B (NF-κB) p65, thereby maintaining the stability of the skin's microenvironment and reshaping normal skin immune defense. This work demonstrates the advantages of STT in RNAi therapy and the potential for future treatment of skin-related diseases.

Tetrahedral framework nucleic acids enhance the chondrogenic potential of human umbilical cord mesenchymal stem cells via the PI3K/AKT axis

The field of regenerative medicine faces a notable challenge in terms of the regeneration of articular cartilage. Without proper treatment, it can lead to osteoarthritis. Based on the research findings, human umbilical cord mesenchymal stem cells (hUMSCs) are considered an excellent choice for regenerating cartilage. However, there is still a lack of suitable biomaterials to control their ability to self-renew and differentiate. To address this issue, in this study using tetrahedral framework nucleic acids (tFNAs) as a new method in an in vitro culture setting to manage the behaviour of hUMSCs was proposed. Then, the influence of tFNAs on hUMSC proliferation, migration and chondrogenic differentiation was explored by combining bioinformatics methods. In addition, a variety of molecular biology techniques have been used to investigate deep molecular mechanisms. Relevant results demonstrated that tFNAs can affect the transcriptome and multiple signalling pathways of hUMSCs, among which the PI3K/Akt pathway is significantly activated. Furthermore, tFNAs can regulate the expression levels of multiple proteins (GSK3β, RhoA and mTOR) downstream of the PI3K-Akt axis to further enhance cell proliferation, migration and hUMSC chondrogenic differentiation. tFNAs provide new insight into enhancing the chondrogenic potential of hUMSCs, which exhibits promising potential for future utilization within the domains of AC regeneration and clinical treatment.

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.

Tetrahedral framework nucleic acids inhibit pathological neovascularization and vaso-obliteration in ischaemic retinopathy via PI3K/AKT/mTOR signalling pathway

This study aimed to explore the effect and the molecular mechanism of tetrahedral framework nucleic acids (tFNAs), a novel self-assembled nanomaterial with excellent biocompatibility and superior endocytosis ability, in inhibition of pathological retinal neovascularization (RNV) and more importantly, in amelioration of vaso-obliteration (VO) in ischaemic retinopathy. tFNAs were synthesized from four single-stranded DNAs (ssDNAs). Cell proliferation, wound healing and tube formation assays were performed to explore cellular angiogenic functions in vitro. The effects of tFNAs on reducing angiogenesis and inhibiting VO were explored by oxygen-induced retinopathy (OIR) model in vivo. In vitro, tFNAs were capable to enter endothelial cells (ECs), inhibit cell proliferation, tube formation and migration under hypoxic conditions. In vivo, tFNAs successfully reduce RNV and inhibit VO in OIR model via the PI3K/AKT/mTOR/S6K pathway, while vascular endothelial growth factor fusion protein, Aflibercept, could reduce RNV but not inhibit VO. This study provides a theoretical basis for the further understanding of RNV and suggests that tFNAs might be a novel promising candidate for the treatment of blind-causing RNV.

Enhanced enzymatic activity and conformational stability of catalase in presence of tetrahedral DNA nanostructures: A biophysical and kinetic study

The emergence of DNA nanotechnology has shown enormous potential in a vast array of applications, particularly in the medicinal and theranostics fields. Nevertheless, the knowledge of the compatibility between DNA nanostructures and cellular proteins is largely unknown. Herein, we report the biophysical interaction between proteins (circulatory protein bovine serum albumin, BSA, and the cellular enzyme bovine liver catalase, BLC) and tetrahedral DNA (tDNAs), which are well-known nanocarriers for therapeutics. Interestingly, the secondary conformation of BSA or BLC was unaltered in the presence of tDNAs which supports the biocompatible property of tDNA. In addition, thermodynamic studies showed that the binding of tDNAs with BLC has a stable non-covalent interaction via hydrogen bond and van der Waals contact, which is indicative of a spontaneous reaction. Furthermore, the catalytic activity of BLC was increased in the presence of tDNAs during 24 h of incubation. These findings indicate that the presence of tDNA nanostructures not only ensures a steady secondary conformation of proteins, but also stabilize the intracellular proteins like BLC. Surprisingly, our investigation discovered that tDNAs have no effect on albumin proteins, either by interfering or by adhering to the extracellular proteins. These findings will aid in the design of future DNA nanostructures for biomedical applications by increasing the knowledge on the biocompatible interaction of tDNAs with biomacromolecules.

Nucleic acid nanostructures for in vivo applications: The influence of morphology on biological fate

The development of programmable biomaterials for use in nanofabrication represents a major advance for the future of biomedicine and diagnostics. Recent advances in structural nanotechnology using nucleic acids have resulted in dramatic progress in our understanding of nucleic acid-based nanostructures (NANs) for use in biological applications. As the NANs become more architecturally and functionally diverse to accommodate introduction into living systems, there is a need to understand how critical design features can be controlled to impart desired performance in vivo. In this review, we survey the range of nucleic acid materials utilized as structural building blocks (DNA, RNA, and xenonucleic acids), the diversity of geometries for nanofabrication, and the strategies to functionalize these complexes. We include an assessment of the available and emerging characterization tools used to evaluate the physical, mechanical, physiochemical, and biological properties of NANs in vitro. Finally, the current understanding of the obstacles encountered along the in vivo journey is contextualized to demonstrate how morphological features of NANs influence their biological fates. We envision that this summary will aid researchers in the designing novel NAN morphologies, guide characterization efforts, and design of experiments and spark interdisciplinary collaborations to fuel advancements in programmable platforms for biological applications.

Entropy-Driven Three-Dimensional DNA Nanofireworks for Simultaneous Real-Time Imaging of Telomerase and MicroRNA in Living Cells

Real-time monitoring of different types of intracellular tumor-related biomarkers is of key importance for the identification of tumor cells. However, it is hampered by the low abundance of biomarkers, inefficient free diffusion of reactants, and complex cytoplasmic milieu. Herein, we present a stable and general method for in situ imaging of microRNA-21 and telomerase utilizing simple highly integrated dual tetrahedral DNA nanostructures (TDNs) that can naturally enter cells, which could initiate to form the three-dimensional (3D) higher-order DNA superstructures (DNA nanofireworks, DNFs) through a reliable target-triggered entropy-driven strand displacement reaction in living cells for remarkable signal amplification. Importantly, the excellent biostability, biocompatibility, and sensitivity of this approach benefited from (i) the precise multidirectional arrangement of probes with a pure DNA structure and (ii) the local target concentration enhanced by the spatially confined microdomain inside the DNFs. This strategy provides a pivotal molecular toolbox for broad applications such as biomedical imaging and early precise cancer diagnosis.

Tetrahedral-Framework Nucleic Acid Loaded with MicroRNA-155 Enhances Immunocompetence in Cyclophosphamide-Induced Immunosuppressed Mice by Modulating Dendritic Cells and Macrophages

Nanomaterials are often used as immunomodulators because they can be tailored by a controllable process. In this work, a complex based on a tetrahedral framework nucleic acid delivery system and MicroRNA-155, known as T-155, is synthesized for the modulation of immunosuppression. In vivo, T-155 ameliorated spleen and thymus damage and hematopoiesis suppression in cyclophosphamide-induced immunosuppressed mice by promoting T-cell proliferation to resist oxidative stress. In vitro, T-155 induced immature dendritic cells (DCs) to differentiate into mature DCs by the ERK1/2 pathway and converted M0 macrophages (Mφ) into the M1 type by the NF-κB pathway to enhance the surveillance capabilities of antigen-presenting cells. The experimental results suggest that T-155 has therapeutic potential as an immunomodulator for immunosuppression.

A dynamic DNA tetrahedron framework for active targeting

An active targeting strategy-enabled DNA tetrahedron delivery vehicle could facilitate stable drug encapsulation and stimuli-responsive on-demand release, building a universal platform for different drug delivery requirements. Owing to the excellent biocompatible nature, programmability and remarkable cell and tissue permeability, the tetrahedral DNA nanostructure (TDN) has proven its value in the delivery of various bioactive molecules. We previously described this as a static multifunctional complex in our earlier protocol. However, static structures and passive targeting behavior might introduce off-target effects under complicated biological conditions. Therefore, in this Protocol Extension, we present a major update of the TDN delivery vehicle enabling an active targeting strategy to be used for stimuli-sensitive conformation changes and on-site cargo release, which could avoid drawbacks, including complex and time-consuming fabrication processes and undetermined cell penetration ability of other DNA-based delivery vehicles. Upon exquisite design of TDN size based on cargo type, one-pot annealing is applied to fabricate the Tiamat-designed TDN exoskeleton. Then the design of the dynamic DNA apparatus can be based on the target and environmental stimuli, including DNA strand hybridization-based and pH-sensitive DNA apparatus, and careful titration of strand lengths and mismatches is achieved using polyacrylamide and agarose gel electrophoresis, or fluorophore modifications. Finally, cargo loading strategies are designed, including site and stand titration and cargo encapsulation verification. The dynamic structures show promising targetability and effectiveness in antitumor and anti-inflammatory treatment in vitro and in vivo. Assembly and characterization in the lab takes ~5 d, and the timing for the verification of biostability and biological applications depends on the uses.

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.

Advances in regenerative medicine applications of tetrahedral framework nucleic acid-based nanomaterials: an expert consensus recommendation

With the emergence of DNA nanotechnology in the 1980s, self-assembled DNA nanostructures have attracted considerable attention worldwide due to their inherent biocompatibility, unsurpassed programmability, and versatile functions. Especially promising nanostructures are tetrahedral framework nucleic acids (tFNAs), first proposed by Turberfield with the use of a one-step annealing approach. Benefiting from their various merits, such as simple synthesis, high reproducibility, structural stability, cellular internalization, tissue permeability, and editable functionality, tFNAs have been widely applied in the biomedical field as three-dimensional DNA nanomaterials. Surprisingly, tFNAs exhibit positive effects on cellular biological behaviors and tissue regeneration, which may be used to treat inflammatory and degenerative diseases. According to their intended application and carrying capacity, tFNAs could carry functional nucleic acids or therapeutic molecules through extended sequences, sticky-end hybridization, intercalation, and encapsulation based on the Watson and Crick principle. Additionally, dynamic tFNAs also have potential applications in controlled and targeted therapies. This review summarized the latest progress in pure/modified/dynamic tFNAs and demonstrated their regenerative medicine applications. These applications include promoting the regeneration of the bone, cartilage, nerve, skin, vasculature, or muscle and treating diseases such as bone defects, neurological disorders, joint-related inflammatory diseases, periodontitis, and immune diseases.

Broadening the Horizons of RNA Delivery Strategies in Cancer Therapy

RNA-based therapy is a promising and innovative strategy for cancer treatment. However, poor stability, immunogenicity, low cellular uptake rate, and difficulty in endosomal escape are considered the major obstacles in the cancer therapy process, severely limiting the development of clinical translation and application. For efficient and safe transport of RNA into cancer cells, it usually needs to be packaged in appropriate carriers so that it can be taken up by the target cells and then be released to the specific location to perform its function. In this review, we will focus on up-to-date insights of the RNA-based delivery carrier and comprehensively describe its application in cancer therapy. We briefly discuss delivery obstacles in RNA-mediated cancer therapy and summarize the advantages and disadvantages of different carriers (cationic polymers, inorganic nanoparticles, lipids, etc.). In addition, we further summarize and discuss the current RNA therapeutic strategies approved for clinical use. A comprehensive overview of various carriers and emerging delivery strategies for RNA delivery, as well as the current status of clinical applications and practice of RNA medicines are classified and integrated to inspire fresh ideas and breakthroughs.

A Mini-Review of Diagnostic and Therapeutic Nano-Tools for Pancreatitis

Pancreatitis is an inflammatory reaction of pancreatic tissue digestion, edema, bleeding and even necrosis caused by activation of pancreatin due to various causes. In particular, patients with severe acute pancreatitis (SAP) often suffer from secondary infection, peritonitis and shock, and have a high mortality rate. Chronic pancreatitis (CP) can cause permanent damage to the pancreas. Due to the innate characteristics, structure and location of the pancreas, there is no effective treatment, only relief of symptoms. Especially, AP is an unpredictable and potentially fatal disease, and the timely diagnosis and treatment remains a major challenge. With the rapid development of nanomedicine technology, many potential tools can be used to address this problem. In this review, we have introduced the pathophysiological processes of pancreatitis to understanding its etiology and severity. Most importantly, the current progress in the diagnosis and treatment tools of pancreatitis based on nanomedicine is summarized and prospected.

Myelosuppression Alleviation and Hematopoietic Regeneration by Tetrahedral-Framework Nucleic-Acid Nanostructures Functionalized with Osteogenic Growth Peptide

As major complications of chemoradiotherapy, myelosuppression and hematopoietic-system damage severely affect immunologic function and can delay or even terminate treatment for cancer patients. Although several specific cytokines have been used for hematopoiesis recovery, their effect is limited, and they may increase the risk of tumor recurrence. In this study, osteogenic growth peptide functionalized tetrahedral framework nucleic-acid nanostructures (OGP-tFNAs) are prepared; they combine the positive hematopoiesis stimulating effect of OGP and the drug carrying function of tFNAs. The potential of OGP-tFNAs for hematopoietic stimulation and microenvironment regulation is investigated. It is shown that OGP-tFNAs can protect bone marrow stromal cells from 5-fluorouracil (5-FU)-induced DNA damage and apoptosis. OGP-tFNAs pretreatment activates the extracellularly regulated protein kinase signal and downregulates apoptosis-related proteins. OGP-tFNAs also alleviate the chemotherapy-induced inhibition of hematopoiesis-related cytokine expression, which is crucial for hematopoiesis reconstitution. In conclusion, OGP-tFNAs can protect hematopoietic cells and their microenvironment from chemotherapy-induced injuries and myelosuppression, while promoting hematopoiesis regeneration.

A Tetrahedral Framework DNA-Based Bioswitchable miRNA Inhibitor Delivery System: Application to Skin Anti-Aging

MicroRNA (miR)-based therapy shows strong potential; however, structural limitations pose a challenge in fully exploiting its biomedical functionality. Tetrahedral framework DNA (tFNA) has proven to be an ideal vehicle for miR therapy. Inspired by the ancient Chinese myth "Sun and Immortal Birds," a novel bioswitchable miR inhibitor delivery system (BiRDS) is designed with three miR inhibitors (the three immortal birds) and a nucleic acid core (the central sun). The BiRDS fuses miR inhibitors within the framework, maximizing their loading capacity, while allowing the system to retain the characteristics of small-sized tFNA and avoiding uncertainty associated with RNA exposure in traditional loading protocols. The RNase H-responsive sequence at the tail of each "immortal bird" enables the BiRDS to transform from a 3D to a 2D structure upon entering cells, promoting the delivery of miR inhibitors. To confirm the application potential, the BiRDS is used to deliver the miR-31 inhibitor, with antiaging effects on hair follicle stem cells, into a skin aging model. Superior skin penetration ability and RNA delivery are observed with significant anti-aging effects. These findings demonstrate the capability and editability of the BiRDS to improve the stability and delivery efficacy of miRs for future innovations.

Determining the Cytosolic Stability of Small DNA Nanostructures In Cellula

DNA nanostructures have proven potential in biomedicine. However, their intracellular interactions─especially cytosolic stability─remain mostly unknown and attempts to discern this are confounded by the complexities of endocytic uptake and entrapment. Here, we bypass the endocytic uptake and evaluate the DNA structural stability directly in live cells. Commonly used DNA structures─crosshairs and a tetrahedron─were labeled with a multistep Förster resonance energy transfer dye cascade and microinjected into the cytosol of transformed and primary cells. Energy transfer loss, as monitored by fluorescence microscopy, reported the structure's direct time-resolved breakdown in cellula. The results showed rapid degradation of the DNA crosshair within 20 min, while the tetrahedron remained consistently intact for at least 1 h postinjection. Nuclease assays in conjunction with a current understanding of the tetrahedron's torsional rigidity confirmed its higher stability. Such studies can inform design parameters for future DNA nanostructures where programmable degradation rates may be required.

Tetrahedral Framework Nucleic Acids Can Alleviate Taurocholate-Induced Severe Acute Pancreatitis and Its Subsequent Multiorgan Injury in Mice

Severe acute pancreatitis (SAP) is an inflammatory disease of the pancreas accompanied by tissue injury and necrosis. It not only affects the pancreas but also triggers a systemic inflammatory response that leads to multiorgan failure or even death. Moreover, there is no effective treatment currently that can reverse the disease progression. In this study, tetrahedral framework nucleic acids (tFNAs) were utilized to treat SAP in mice for the first time and proved to be effective in suppressing inflammation and preventing pathological cell death. Serum levels of pancreatitis-related biomarkers witnessed significant changes after tFNAs treatment. Reduction in the expression of certain cytokines involved in local and systemic inflammatory response were observed, together with alteration in proteins related to cell death and apoptosis. Collectively, our results demonstrate that tFNAs could both alleviate SAP and its subsequent multiorgan injury in mice, thus offering a novel and effective option to deal with SAP in the future.