Bivalent mRNA vaccines against three SARS-CoV-2 variants mediated by new ionizable lipid nanoparticles

Emerging mRNA Technology for Liver Disease Therapy

Liver diseases have consistently posed substantial challenges to global health. It is crucial to find innovative methods to effectively prevent and treat these diseases. In recent times, there has been an increasing interest in the use of mRNA formulations that accumulate in liver tissue for the treatment of hepatic diseases. In this review, we start by providing a detailed introduction to the mRNA technology. Afterward, we highlight types of liver diseases, discussing their causes, risks, and common therapeutic strategies. Additionally, we summarize the latest advancements in mRNA technology for the treatment of liver diseases. This includes systems based on hepatocyte growth factor, hepatitis B virus antibody, left-right determination factor 1, human hepatocyte nuclear factor α, interleukin-12, methylmalonyl-coenzyme A mutase, etc. Lastly, we provide an outlook on the potential of mRNA technology for the treatment of liver diseases, while also highlighting the various technical challenges that need to be addressed. Despite these difficulties, mRNA-based therapeutic strategies may change traditional treatment methods, bringing hope to patients with liver diseases.

Engineered mRNA Delivery Systems for Biomedical Applications

Messenger RNA (mRNA)-based therapeutic strategies have shown remarkable promise in preventing and treating a staggering range of diseases. Optimizing the structure and delivery system of engineered mRNA has greatly improved its stability, immunogenicity, and protein expression levels, which has led to a wider range of uses for mRNA therapeutics. Herein, a thorough analysis of the optimization strategies used in the structure of mRNA is first provided and delivery systems are described in great detail. Furthermore, the latest advancements in biomedical engineering for mRNA technology, including its applications in combatting infectious diseases, treating cancer, providing protein replacement therapy, conducting gene editing, and more, are summarized. Lastly, a perspective on forthcoming challenges and prospects concerning the advancement of mRNA therapeutics is offered. Despite these challenges, mRNA-based therapeutics remain promising, with the potential to revolutionize disease treatment and contribute to significant advancements in the biomedical field.

Clinical and Preclinical Methods of Heat-Stabilization of Human Vaccines

Vaccines have historically faced challenges regarding stability, especially in regions lacking a robust cold chain infrastructure. This review delves into established and emergent techniques to improve the thermostability of vaccines. We discuss the widely practiced lyophilization method, effectively transforming liquid vaccine formulations into a solid powdered state, enhancing storage and transportation ability. However, potential protein denaturation during lyophilization necessitates alternative stabilization methods. Cryoprotectants, namely, starch and sugar molecules, have shown promise in protecting vaccine antigens and adjuvants from denaturation and augmenting the stability of biologics during freeze-drying. Biomineralization, a less studied yet innovative approach, utilizes inorganic or organic-inorganic hybrids to encapsulate biological components of vaccines with a particular emphasis on metal-organic coordination polymers. Encapsulation in organic matrices to form particles or microneedles have also been studied in the context of vaccine thermostability, showing some ability to store outside the cold-chain. Unfortunately, few of these techniques have advanced to clinical trials that evaluate differences in storage conditions. Nonetheless, early trials suggest that alternative storage techniques are viable and emphasize the need for more comprehensive studies. This review underscores the pressing need for heat-stable vaccines, especially in light of the increasing global distribution challenges. Combining traditional methods with novel approaches holds promise for the future adaptability of vaccine distribution and use.

Trivalent mRNA Vaccine against SARS-CoV-2 and Variants with Effective Immunization

mRNA vaccines encoding a single spike protein effectively prevent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. However, the emergence of SARS-CoV-2 variants leads to a wide range of immune evasion. Herein, a unique trivalent mRNA vaccine based on ancestral SARS-CoV-2, Delta, and Omicron variant spike receptor-binding domain (RBD) mRNAs was developed to tackle the immune evasion of the variants. First, three RBD mRNAs of SARS-CoV-2, Delta, and Omicron were coencapsulated into lipid nanoparticles (LNPs) by using microfluidic technology. After that, the physicochemical properties and time-dependent storage stability of the trivalent mRNA vaccine nanoformulation were tested by using dynamic light scattering (DLS). In vitro, the trivalent mRNA vaccine exhibited better lysosomal escape ability, transfection efficiency, and biocompatibility than did the commercial transfection reagent Lipo3000. In addition, Western blot analyses confirmed that the three RBD proteins can be detected in cells transfected with the trivalent mRNA vaccine. Furthermore, ex vivo imaging analysis indicated that the livers of BALB/c mice had the strongest protein expression levels after intramuscular (IM) injection. Using a prime-boost strategy, this trivalent vaccine elicited robust humoral and T-cell immune responses in both the high-dose and low-dose groups and showed no toxicity in BALB/c mice. Three specific IgG antibodies in the high-dose group against SARS-CoV-2, Delta, and Omicron variants approached ∼1/1,833,333, ∼1/1,866,667, and ∼1/925,000, respectively. Taken together, two doses of inoculation with the trivalent mRNA vaccine may provide broad and effective immunization responses against SARS-CoV-2 and variants.