Synthetic mRNA: Production, Introduction into Cells, and Physiological Consequences

Comprehensive Impurity Profiling of mRNA: Evaluating Current Technologies and Advanced Analytical Techniques

In vitro transcription (IVT) of mRNA is a versatile platform for a broad range of biotechnological applications. Its rapid, scalable, and cost-effective production makes it a compelling choice for the development of mRNA-based cancer therapies and vaccines against infectious diseases. The impurities generated during mRNA production can potentially impact the safety and efficacy of mRNA therapeutics, but their structural complexity has not been investigated in detail yet. This study pioneers a comprehensive profiling of IVT mRNA impurities, integrating current technologies with innovative analytical tools. We have developed highly reproducible, efficient, and stability-indicating ion-pair reversed-phase liquid chromatography and capillary gel electrophoresis methods to determine the purity of mRNA from different suppliers. Furthermore, we introduced the applicability of microcapillary electrophoresis for high-throughput (<1.5 min analysis time per sample) mRNA impurity profiling. Our findings revealed that impurities are mainly attributed to mRNA variants with different poly(A) tail lengths due to aborted additions or partial hydrolysis and the presence of double-stranded mRNA (dsRNA) byproducts, particularly the dsRNA 3'-loop back form. We also implemented mass photometry and native mass spectrometry for the characterization of mRNA and its related product impurities. Mass photometry enabled the determination of the number of nucleotides of different mRNAs with high accuracy as well as the detection of their size variants [i.e., aggregates and partial and/or total absence of the poly(A) tail], thus providing valuable information on mRNA identity and integrity. In addition, native mass spectrometry provided insights into mRNA intact mass, heterogeneity, and important sequence features such as poly(A) tail length and distribution. This study highlights the existing bottlenecks and opportunities for improvement in the analytical characterization of IVT mRNA, thus contributing to the refinement and streamlining of mRNA production, paving the way for continued advancements in biotechnological applications.

Future regenerative medicine developments and their therapeutic applications

Although the currently available pharmacological assays can cure most pathological disorders, they have limited therapeutic value in relieving certain disorders like myocardial infarct, peripheral vascular disease, amputated limbs, or organ failure (e.g. renal failure). Pilot studies to overcome such problems using regenerative medicine (RM) delivered promising data. Comprehensive investigations of RM in zebrafish or reptilians are necessary for better understanding. However, the precise mechanisms remain poorly understood despite the tremendous amount of data obtained using the zebrafish model investigating the exact mechanisms behind their regenerative capability. Indeed, understanding such mechanisms and their application to humans can save millions of lives from dying due to potentially life-threatening events. Recent studies have launched a revolution in replacing damaged human organs via different approaches in the last few decades. The newly established branch of medicine (known as Regenerative Medicine aims to enhance natural repair mechanisms. This can be done through the application of several advanced broad-spectrum technologies such as organ transplantation, tissue engineering, and application of Scaffolds technology (support vascularization using an extracellular matrix), stem cell therapy, miRNA treatment, development of 3D mini-organs (organoids), and the construction of artificial tissues using nanomedicine and 3D bio-printers. Moreover, in the next few decades, revolutionary approaches in regenerative medicine will be applied based on artificial intelligence and wireless data exchange, soft intelligence biomaterials, nanorobotics, and even living robotics capable of self-repair. The present work presents a comprehensive overview that summarizes the new and future advances in the field of RM.

Rapid differentiation of hiPSCs into functional oligodendrocytes using an OLIG2 synthetic modified messenger RNA

Transcription factors (TFs) have been introduced to drive the highly efficient differentiation of human-induced pluripotent stem cells (hiPSCs) into lineage-specific oligodendrocytes (OLs). However, effective strategies currently rely mainly on genome-integrating viruses. Here we show that a synthetic modified messenger RNA (smRNA)-based reprogramming method that leads to the generation of transgene-free OLs has been developed. An smRNA encoding a modified form of OLIG2, in which the serine 147 phosphorylation site is replaced with alanine, OLIG2^S147A, is designed to reprogram hiPSCs into OLs. We demonstrate that repeated administration of the smRNA encoding OLIG2^S147A lead to higher and more stable protein expression. Using the single-mutant OLIG2 smRNA morphogen, we establish a 6-day smRNA transfection protocol, and glial induction lead to rapid NG2⁺ OL progenitor cell (OPC) generation (>70% purity) from hiPSC. The smRNA-induced NG2⁺ OPCs can mature into functional OLs in vitro and promote remyelination in vivo. Taken together, we present a safe and efficient smRNA-driven strategy for hiPSC differentiation into OLs, which may be utilized for therapeutic OPC/OL transplantation in patients with neurodegenerative disease.

The use of synthetic modified messenger RNA (smRNA) allows for the differentiation of human-induced pluripotent stem cells (hiPSCs) into lineage-specific oligodendrocytes.

Current status of research on exosomes in general, and for the diagnosis and treatment of kidney cancer in particular

Kidney cancer is a common urological tumour. Owing to its high prevalence and mortality rate, it is the third most malignant tumour of the urinary system, followed by prostate and bladder cancers. It exerts a high degree of malignancy, and most of the distant metastasis occurs at an early stage; it is insensitive to chemoradiotherapy and easily develops drug resistance. The current treatment for kidney cancer mainly includes surgery, interventional embolization and targeted therapy; however, the treatment efficacy is poor. In recent years, the role of exosomes as mediators of intercellular communication and information exchange in the tumour microenvironment in tumour pathogenesis has attracted much attention. Exosomes are rich in bioactive substances such as nucleic acids, proteins and lipids and are involved in angiogenesis, immune regulation, drug resistance, formation of pre-metastatic niche, invasion and metastasis. This article reviews the ongoing research and applications of exosomes for the diagnosis and treatment of kidney cancer.

Polymeric Delivery of Therapeutic Nucleic Acids

The advent of genome editing has transformed the therapeutic landscape for several debilitating diseases, and the clinical outlook for gene therapeutics has never been more promising. The therapeutic potential of nucleic acids has been limited by a reliance on engineered viral vectors for delivery. Chemically defined polymers can remediate technological, regulatory, and clinical challenges associated with viral modes of gene delivery. Because of their scalability, versatility, and exquisite tunability, polymers are ideal biomaterial platforms for delivering nucleic acid payloads efficiently while minimizing immune response and cellular toxicity. While polymeric gene delivery has progressed significantly in the past four decades, clinical translation of polymeric vehicles faces several formidable challenges. The aim of our Account is to illustrate diverse concepts in designing polymeric vectors towards meeting therapeutic goals of in vivo and ex vivo gene therapy. Here, we highlight several classes of polymers employed in gene delivery and summarize the recent work on understanding the contributions of chemical and architectural design parameters. We touch upon characterization methods used to visualize and understand events transpiring at the interfaces between polymer, nucleic acids, and the physiological environment. We conclude that interdisciplinary approaches and methodologies motivated by fundamental questions are key to designing high-performing polymeric vehicles for gene therapy.

Therapeutic Prospects of mRNA-Based Gene Therapy for Glioblastoma

The treatment of glioblastoma has been a big challenge for decades in the oncological field mainly owing to its unique biological characteristics, such as high heterogeneity, diffusing invasiveness, and capacity to resist conventional therapies. The mRNA-based therapeutic modality holds many superior features, including easy manipulation, rapid and transient expression, and adaptive convertibility without mutagenesis, which are suitable for dealing with glioblastoma's complexity and variability. Synthetic anticancer mRNAs carried by various vehicles act as the ultimate attackers of the tumor across biological barriers. In this modality, specifically targeted glioblastoma treatment can be guaranteed by adding targeting molecules at certain levels. The choice of mRNA-bearing vehicle and administration method is a fully patient-tailored selection. This review covers the advantages and possible limitations of mRNA-based gene therapy, the in vitro synthesis of mRNA, the feasible methods for synthetic mRNA delivery and clinical therapeutic prospects of mRNA-based gene therapy for glioblastoma.

Modified ARCA analogs providing enhanced translational properties of capped mRNAs

Nowadays gene manipulation techniques ("DNA therapy") undergo progressive development and become widely used in industry and medicine. Since new advances in mRNA technologies are capable for obtaining particles with increased stability and translational efficiency, RNA become an attractive alternative for advancement of DNA therapy. For the past years studies have been conducted to explore different modification in mRNA cap structure and its effect on RNA properties. Recently we have shown that modification of the cap structure at the N2 position of 7-methylguanosine leads to an enhancement in translation inhibition. Currently, we have decided to exploit translational properties of mRNA capped with the ARCA (anti-reversed cap) analogs modified within N2 position of purine moiety s. We designed and synthesized three new dinucleotide cap analogs and investigated them in the rabbit reticulocyte lysate (RRL) and the human embryonic kidney derived HEK293 cell line, in vitro translational model systems. The obtained data indicate that, in both translational assays, the cap analogs synthesized by us when incorporated into mRNA improved its translational properties compared to the ARCA capped transcripts. Furthermore, the introduced modifications enhanced stability of the capped transcripts in HEK293 cells, which become higher compared to that of the transcripts capped with regular cap or with ARCA. Additionally one of the synthesized cap analogs revealed strong translation inhibition potency in RRL system, with IC₅₀ value 1.7 µM.