A Thermal and Enzymatic Dual-Stimuli Responsive DNA-Based Nanomachine for Controlled mRNA Delivery

Pharmaceutical strategies for optimized mRNA expression

Messenger RNA (mRNA)-based immunotherapies and protein in situ production therapies hold great promise for addressing theoretically all the diseases characterized by aberrant protein levels. The safe, stable, and precise delivery of mRNA to target cells via appropriate pharmaceutical strategies is a prerequisite for its optimal efficacy. In this review, we summarize the structural characteristics, mode of action, development prospects, and limitations of existing mRNA delivery systems from a pharmaceutical perspective, with an emphasis on the impacts from formulation adjustments and preparation techniques of non-viral vectors on mRNA stability, target site accumulation and transfection efficiency. In addition, we introduce strategies for synergistical combination of mRNA and small molecules to augment the potency or mitigate the adverse effects of mRNA therapeutics. Lastly, we delve into the challenges impeding the development of mRNA drugs while exploring promising avenues for future advancements.

An injectable adhesive hydrogel for photothermal ablation and antitumor immune activation against bacteria-associated oral squamous cell carcinoma

Pathogenic bacteria are closely associated with the occurrence, development and metastasis of oral squamous cell carcinoma (OSCC). Antibacterial therapy has been considered an enhancement strategy to suppress bacteria-associated tumors and promote anti-tumor immune responses. Herein, we developed an injectable adhesive hydrogel, PNIPAM/DL@TIR, for the in situ photothermal ablation and robust stimulation of antitumor immunity against OSCC colonized by Porphyromonas gingivalis (Pg), one of the major oral pathogenic bacteria. PNIPAM/DL@TIR, composed of poly(N-isopropylacrylamide), demethylated lignin, and TAT peptide-conjugated IR820, was prepared using a simple dissolve-dry-swell solvent exchange method. Upon 808 nm laser irradiation, PNIPAM/DL@TIR exerted photothermal effects to ablate Pg-colonized OSCC and generate dual tumor and bacterial antigens. Owing to its large number of catechol groups, PNIPAM/DL@TIR efficiently captured these antigens to form an in situ antigen repository, thereby eliciting robust and durable antitumor immune responses. Proteomic analysis revealed that the captured antigens comprised both tumor neoantigens and bacterial antigens. The catechol groups endowed PNIPAM/DL@TIR with antioxidant activity, which was also conducive to stimulating antitumor immunity. Altogether, this study develops an injectable adhesive hydrogel and provides a combination strategy for treating bacteria-associated OSCC. STATEMENT OF SIGNIFICANCE: In this study, we developed an injectable adhesive hydrogel, PNIPAM/DL@TIR, for in situ photothermal ablation and robust stimulation of antitumor immunity against OSCC colonized by Porphyromonas gingivalis, one of the major oral pathogenic bacteria. PNIPAM/DL@TIR, which consists of poly(N-isopropylacrylamide), demethylated lignin, and TAT peptide-conjugated IR820 exhibited outstanding photothermal performance. Owing to the presence of catechol groups, PNIPAM/DL@TIR has good bioadhesive properties and can capture protein antigens to form in situ antigen repository, thus initiating robust and long-term antitumor immune responses. In addition, PNIPAM/DL@TIR exhibited strong antioxidant activity that is favorable for promoting antitumor immunity. In the mouse model of OSCC with bacterial infection, PNIPAM/DL@TIR not only ablated the primary tumors upon NIR laser irradiation, but also induced tumor and bacterial vaccination in situ to suppress distant tumors and lung metastasis.

Bioinspired Spatiotemporal Management toward RNA Therapies

Ribonucleic acid (RNA)-based therapies have become an attractive topic in disease intervention, especially with some that have been approved by the FDA such as the mRNA COVID-19 vaccine (Comirnaty, Pfizer-BioNTech, and Spikevax, Moderna) and Patisiran (siRNA-based drug for liver delivery). However, extensive applications are still facing challenges in delivering highly negatively charged RNA to the targeted site. Therapeutic delivery strategies including RNA modifications, RNA conjugates, and RNA polyplexes and delivery platforms such as viral vectors, nanoparticle-based delivery platforms, and hydrogel-based delivery platforms as potential nucleic acid-releasing depots have been developed to enhance their cellular uptake and protect nucleic acid from being degraded by immune systems. Here, we review the growing number of viral vectors, nanoparticles, and hydrogel-based RNA delivery systems; describe RNA loading/release mechanism induced by environmental stimulations including light, heat, pH, or enzyme; discuss their physical or chemical interactions; and summarize the RNA therapeutics release period (temporal) and their target cells/organs (spatial). Finally, we describe current concerns, highlight current challenges and future perspectives of RNA-based delivery systems, and provide some possible research areas that provide opportunities for clinical translation of RNA delivery carriers.

Cellular Trafficking of Nanotechnology-Mediated mRNA Delivery

Messenger RNA (mRNA)-based therapy has emerged as a powerful, safe, and rapidly scalable therapeutic approach that involves technologies for both mRNA itself and the delivery vehicle. Although there are some unique challenges for different applications of mRNA therapy, a common challenge for all mRNA therapeutics is the transport of mRNA into the target cell cytoplasm for sufficient protein expression. This review is focused on the behaviors at the cellular level of nanotechnology-mediated mRNA delivery systems, which have not been comprehensively reviewed yet. First, the four main therapeutic applications of mRNA are introduced, including immunotherapy, protein replacement therapy, genome editing, and cellular reprogramming. Second, common types of mRNA cargos and mRNA delivery systems are summarized. Third, strategies to enhance mRNA delivery efficiency during the cellular trafficking process are highlighted, including accumulation to the cell, internalization into the cell, endosomal escape, release of mRNA from the nanocarrier, and translation of mRNA into protein. Finally, the challenges and opportunities for the development of nanotechnology-mediated mRNA delivery systems are presented. This review can provide new insights into the future fabrication of mRNA nanocarriers with desirable cellular trafficking performance.

Polyplex designs for improving the stability and safety of RNA therapeutics

Nanoparticle-based delivery systems have contributed to the recent clinical success of RNA therapeutics, including siRNA and mRNA. RNA delivery using polymers has several distinct properties, such as enabling RNA delivery into extra-hepatic organs, modulation of immune responses to RNA, and regulation of intracellular RNA release. However, delivery systems should overcome safety and stability issues to achieve widespread therapeutic applications. Safety concerns include direct damage to cellular components, innate and adaptive immune responses, complement activation, and interaction with surrounding molecules and cells in the blood circulation. The stability of the delivery systems should balance extracellular RNA protection and controlled intracellular RNA release, which requires optimization for each RNA species. Further, polymer designs for improving safety and stability often conflict with each other. This review covers advances in polymer-based approaches to address these issues over several years, focusing on biological understanding and design concepts for delivery systems rather than material chemistry.

Advances of medical nanorobots for future cancer treatments

Early detection and diagnosis of many cancers is very challenging. Late stage detection of a cancer always leads to high mortality rates. It is imperative to develop novel and more sensitive and effective diagnosis and therapeutic methods for cancer treatments. The development of new cancer treatments has become a crucial aspect of medical advancements. Nanobots, as one of the most promising applications of nanomedicines, are at the forefront of multidisciplinary research. With the progress of nanotechnology, nanobots enable the assembly and deployment of functional molecular/nanosized machines and are increasingly being utilized in cancer diagnosis and therapeutic treatment. In recent years, various practical applications of nanobots for cancer treatments have transitioned from theory to practice, from in vitro experiments to in vivo applications. In this paper, we review and analyze the recent advancements of nanobots in cancer treatments, with a particular emphasis on their key fundamental features and their applications in drug delivery, tumor sensing and diagnosis, targeted therapy, minimally invasive surgery, and other comprehensive treatments. At the same time, we discuss the challenges and the potential research opportunities for nanobots in revolutionizing cancer treatments. In the future, medical nanobots are expected to become more sophisticated and capable of performing multiple medical functions and tasks, ultimately becoming true nanosubmarines in the bloodstream.