The design of the mRNA vaccine involves the selection of in vitro transcription (IVT) systems and nonviral delivery vectors. This study aimed to verify the effect of 5’ and 3’ untranslated region (UTR) sequences on the translation efficiency of mRNA. Three modes of IVT-mRNA systems (IVT-mRNA-n1/n2/n3) with diverse UTRs were constructed, and EGFP (enhanced green fluorescent protein) and HA (hemagglutinin) gene of H3N2 influenza virus were introduced into each of them. The results showed that the mode of 5’ and 3’ UTRs originating from human β-globulin was better than the mode of UTRs from human α-globulin, and the n3 mode was the best. mEGFP-n3, mH3HA-n3, and mLuciferease-n3 were prepared to compare the effect of cationic lipid nanoparticle (LNP) with that of mannose-conjugated LNP (LNP-Man) on the efficiency of gene delivery. The results showed that the effect of LNP-Man was better than that of LNP both in vitro and in vivo. Choosing appropriate ligands might help in vaccine design. After selecting the IVT-mRNA-n3 system and delivery vectors, mRNA vaccines were constructed against the H1N1 influenza virus, and C57BL/6 mice were immunized through intranasal administration. The results showed that mRNA vaccines could elicit both humoral and cellular immune responses and completely protect mice from the tenfold LD₅₀ H1N1 influenza virus challenge.

Staphylococcus aureus is an important pathogen that causes various infections in medical facilities. However, resistance to multiple drugs has made this infection difficult to manage. Thus, new therapeutic strategies are urgently needed to solve this worldwide public health problem. The Streptococcus lactis L16 strain was isolated from the fermented hot chili sauce. To explore whether it can be used as a protective agent against S. aureus infection, we designed a mouse model of S. aureus infection to evaluate the therapeutic potency of S. lactis. Mice were grouped into pre-(P) and post-(T) S. aureus infection groups following oral administration of S. lactis L16. The protection and treatment effects were assessed by examining body weight, internal organ weight, serum cytokines and intestinal secretory IgA alternations. Oral administration of the S. lactis L16 strain reduced the loss of body weight in mice post-infection and alleviated infection-induced hepatomegaly. In particular, the PL16 group (protection with L16) showed more effective resistance to S. aureus than the TL16 group (treatment with L16). The level of serum cytokine interferon gamma following oral administration of the L16 strain was remarkably increased during infection, as were interleukin-4 levels during convalescence. The probiotic L16 strain induced more sIgA production than S. aureus. Our data suggest that S. lactis L16 is an effective strain with anti-Staphylococcus activity. By regulating the Th1/Th2 response, S. lactis can effectively reduce lesions from infection, indicating its therapeutic potential in overcoming antibiotic resistance in this mouse infection model that mimics infections observed in humans.

The Nipah Virus (NiV) is a zoonotic pathogen with the mortality rate of up to 75%, recurring in Asia over the past two decades. Due to increasing the risk of human transmission mediated by various intermediate hosts such as pigs and bats, it is necessary to produce an accurate and reliable point-of-care molecular detection method for NiV field diagnosis. In this study, we designed two pairs of primers targeting the conserved G and P genes and developed a point-of-care nucleic acid detection (POC-NAD) system by integrating one-step RT-PCR, lateral flow immunoassay, and microfluidic technologies. The POC-NAD system shows high specificity and sensitivity, with a Limit of Detection (LoD) of 199.1 copies/rxn. The primers aiming to the conserved sequences enables simultaneous detection of both NiV-M and NiV-B strains. Continuous evaluation of 21 simulated clinical samples demonstrated 100% concordance with RT-PCR results. Lateral flow-based visualization improves the display time and legibility of RT-PCR results. Additionally, microfluidic chips or chambers offer disposable reagent containers and consistent PCR amplification results across various field conditions. Therefore, the diagnostic tool is suitable for real-time nucleic acid testing and NiV surveillance in resource-limited field environments.

Introduction: Porcine deltacoronavirus (PDCoV) is a zoonotic pathogen with a global distribution, capable of infecting both pigs and humans. To mitigate the risk of cross-species transmission and potential outbreaks, it is crucial to characterize novel antiviral genes, particularly those from human hosts.Methods: This research used HIEC-6 to investigate PDCoV infection. HIEC-6 cells were infected with PDCoV. Samples were collected 48 h postinfection for proteomic analysis.Results: We discovered differential expression of MRPS6 gene at 48 h postinfection with PDCoV in HIEC-6 cells. The gene expression initially increased but then decreased. To further explore the role of MRPS6 in PDCoV infection, we conducted experiments involving the overexpression and knockdown of this gene in HIEC-6 and Caco2 cells, respectively. Our findings revealed that overexpression of MRPS6 significantly inhibited PDCoV infection in HIEC-6 cells, while knockdown of MRPS6 in Caco2 cells led to a significant increase of virus titer. Furthermore, we investigated the correlation between PDCoV infection and the expression of MRPS6. Subsequent investigations demonstrated that MRPS6 exerted an augmentative effect on the production of IFN-β through interferon pathway activation, consequently impeding the progression of PDCoV infection in cellular systems. In conclusion, this study utilized proteomic analysis to investigate the differential protein expression in PDCoV-infected HIEC-6 cells, providing evidence for the first time that the MRPS6 gene plays a restrictive role in PDCoV virus infection.Discussion: Our findings initially provide the validation of MRPS6 as an upstream component of IFN-β pathway, in the promotion of IRF3, IRF7, STAT1, STAT2 and IFN-β production of HIEC-6 via dual-activation from interferon pathway.

Porcine epidemic diarrhea is a significant disease that damages the global pig industry. The delay between infection and vaccination allows for a 30–70% mortality rate among piglets. Early virus detection is a more effective disease management strategy for pigs. Unfortunately, most methods rely heavily on skilled personnel and sophisticated equipment, which is not ideal in scenarios requiring cost reduction and efficiency. To address these challenges, our study based on one-step RT-PCR and lateral flow strips developed a reliable, field-deployable, and low-cost nucleic acid detection method for PEDV. The whole process takes about 45 min and the testing cost of each sample is low to $0.3. Moreover, this method is simple to operate, it is possible to complete the entire operation without training. Our clinical application demonstrates a robust diagnostic tool for detecting PEDV in field conditions, thereby providing more time for PEDV epidemic emergency response.

Porcine epidemic diarrhea virus (PEDV) damaged to the intestinal epithelial cells of suckling piglets, resulting in elevated mortality rates and substantial economic losses. This study aimed to evaluate the effect of F. prausnitzii on PEDV invasion and mitochondrial function in cells. Our study demonstrated that F. prausnitzii exhibited strongly adhesion to PEDV virions, thereby preventing their entry into cells and enhancing cell viability. Notably, F. prausnitzii inhibited PEDV-induced apoptosis in Vero-E6 cells, as indicated by decreased activation of PARP, caspase-3/9, and the Bax/Bcl-2 ratio, while preserving mitochondrial structure and membrane potential. Moreover, the adhesion-mediated inhibition of the PEDV-induced mitochondrial apoptotic pathway was correlated with reduced reactive oxygen species (ROS) production and cytochrome c translocation. These results suggested that F. prausnitzii as postbiotic may serve as a preventive measures against different subtype PEDV infection by targeting mitochondrial apoptotic pathways, and broadened the horizons for the antiviral effects of postbiotic.