An mRNA SARS-CoV-2 vaccine employing Charge-Altering Releasable Transporters with a TLR-9 agonist induces neutralizing antibodies and T cell memory

mRNA vaccines against infectious diseases and future direction

Vaccines are used for the control of infectious diseases of animals. Over other types of vaccinations like live attenuated or killed vaccines, mRNA-based vaccines have significant advantages. As only a small portion of the pathogen's genetic material is employed and the dose rate of mRNA-based vaccines is low, there is the least possibility that the pathogen will reverse itself. A carrier or vehicle that shields mRNA-based vaccines from the host's cellular RNases is necessary for their delivery. mRNA vaccines have been shown to be effective and to induce both a cell-mediated immune response and a humoral immune response in clinical trials against various infectious diseases (viral and parasitic) affecting the animals, including rabies, foot and mouth disease, toxoplasmosis, Zikavirus, leishmaniasis, and COVID-19. The current review aims to highlight the use of mRNA-based vaccines both in viral and parasitic diseases of animals.

Toll-like receptor (TLRs) agonists and antagonists for COVID-19 treatments

Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) rapidly infects humans and animals which make coronavirus disease 2019 (COVID-19) a grievous epidemic worldwide which broke out in 2020. According to data analysis of the other coronavirus family, for instance severe acute respiratory syndrome SARS coronavirus (SARS-CoV), can provide experience for the mutation of SARS-CoV-2 and the prevention and treatment of COVID-19. Toll-like receptors (TLRs) as a pattern recognition receptor (PRRs), have an indispensable function in identifying the invader even activate the innate immune system. It is possible for organism to activate different TLR pathways which leads to secretion of proinflammatory cytokines such as Interleukin 1 (IL-1), Interleukin 6 (IL-6), Tumor necrosis factor α (TNFα) and type Ⅰ interferon. As a component of non-specific immunity, TLRs pathway may participate in the SARS-CoV-2 pathogenic processes, due to previous works have proved that TLRs are involved in the invasion and infection of SARS-CoV and MERS to varying degrees. Different TLR, such as TLR2, TLR4, TLR7, TLR8 and TLR9 probably have a double-sided in COVID-19 infection. Therefore, it is of great significance for a correctly acknowledging how TLR take part in the SARS-CoV-2 pathogenic processes, which will be the development of treatment and prevention strategies.

Polyester materials for mRNA delivery

Messenger RNA (mRNA) has recently made important progress in clinical implementation, offering a promising therapeutic option for infectious disease and cancer. However, the nature of mRNA molecules rendered them poorly bioavailable and unstable in vivo, impeding their further clinical application. Therefore, safe and efficient delivery of mRNA therapeutics to the target site is crucial for their successful translation into the clinical setting. Various vectors have been explored for mRNA delivery. Among them, polyesters and their analogs, a family of biodegradable polymers, have exhibited great potential for mRNA delivery. In this short review, the authors briefly introduce mRNA therapeutics, their therapeutic applications and delivery challenges. The authors then presented the typical examples of polyester materials for mRNA delivery to highlight the current progress and discuss the challenges for the rational design of polyester based mRNA delivery vectors. The authors hope to provide a new insight for the design of biodegradable vectors for nucleic acids delivery, thereby promoting their further clinic translation.

Oxymatrine attenuates TNBS-induced colinutis in rats through TLR9/Myd88/NF-κB signal pathway

Objective: Due to its well-known anti-inflammatory property, oxymatrine (OMT) has received more attention on the aspect of treating ulcerative colitis. Although efforts have been undertaken to understand the therapeutic mechanism of OMT on ulcerative colitis (UC), the remedial principle is still ambiguous. Numerous studies have shown that TLR9/Myd88/NF-κB signal pathway played a key role in the pathogenesis of UC. Moreover, TLR9/Myd88/NF-κB signal pathway is a part of the most important pathways for regulating the immune response.Methods: We explored the influence of OMT with different dosages on UC by establishing a 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis model. Moreover, the participation of TLR9/Myd88/NF-κB signal pathway and whether OMT protects against UC though targeting this pathway are further studied.Results: Our data revealed that OMT could significantly relieve the symptom of TNBS-induced colitis in rats by reactivating the tight junction protein and, more important, by inhibiting the activation of TLR9/Myd88/NF-κB pathway and protein expression levels of its downstream inflammatory factors.Conclusion: OMT could relieve colitis in rat models by impacting tight junction proteins' TLR9/Myd88/NF-κB signal pathways and activity.

Novel malaria vaccines

Malaria vaccines hold significant promise for life-saving benefit, especially to children who bear the major burden of malaria mortality. The RTS,S/AS01 malaria vaccine provides moderate efficacy and is being tested in implementation studies. In parallel, multiple strategies are being advanced to test next-generation malaria vaccines, including novel approaches that build on principles learned from RTS,S development, vaccination with radiation-attenuated sporozoites, and development of monoclonal antibodies targeting immunogenic peptides. Novel vaccine delivery approaches are also being advanced, including self-amplifying RNA vaccine delivery, self-assembling protein nanoparticle methods, circumsporozoite protein-based approaches, and whole organism vaccination. Techniques employed for COVID-19 vaccine development should also be considered for malaria vaccination, including sustained release polymer nanoparticle hydrogel vaccination and charge-altering releasable transporters. As vaccine science advances and new approaches optimize knowledge gained, highly effective malaria vaccines that provide sustained protection are within reach.