PF-D-Trimer, a broadly protective SARS-CoV-2 subunit vaccine: immunogenicity and application

The COVID-19 pandemic, caused by the SARS-CoV-2 virus, has had and still has a considerable impact on global public health. One of the characteristics of SARS-CoV-2 is a surface homotrimeric spike protein, the primary responsible for the host immune response upon infection. Here we show the preclinical studies of a broad protective SARS-CoV-2 subunit vaccine developed from our Trimer Domain platform using the Delta spike protein, from antigen design to purification, vaccine evaluation and manufacturability. The prefusion trimerized Delta spike protein, PF-D-Trimer, was highly expressed in Chinese hamster ovary (CHO) cells, purified by a rapid one-step anti-Trimer Domain monoclonal antibody immunoaffinity process and prepared as a vaccine formulation with an adjuvant. The immunogenicity studies demonstrated that this vaccine candidate induces robust immune responses in mouse, rat and Syrian hamster models. It also protects K18-hACE2 transgenic mice in a homologous virus challenge. The neutralizing antibodies induced by this vaccine display a cross-reactive capacity against the ancestral WA1 and Delta variants as well as different Omicron, including BA.5.2. The Trimer Domain platform was proven to be a key technology in the rapid production of the PF-D-Trimer vaccine and may be crucial to accelerate the development of updated versions of SARS-CoV-2 vaccines.

Qualitative and quantitative determination of the primary active components and metabolites in human plasma after oral administration of Shuanghuanglian liquid.

Shuanghuanglian oral liquid is a common traditional Chinese medicine used to treat respiratory tract infections. Its major components are baicalin, chlorogenic acid, and forsythin. In this study, the main drug-related components in human plasma after oral administration of Shuanghuanglian were initially identified using ultra-performance liquid chromatography-ultraviolet detector/quadrupole time-of-flight mass spectrometry. Thirteen components from baicalin were identified, including the parent drug baicalin and aglycone baicalein. Only one metabolite related to chlorogenic acid, a sulfate conjugate formed after hydrolysis, and one metabolite related to forsythin, a sulfate conjugate of forsythin aglycone, were detected. Subsequently, a liquid chromatography-tandem mass spectrometry method was established and validated to simultaneously determine baicalin and baicalein, the primary active components. After simple protein precipitation, the analytes were separated on a BEH C18 column using a 5 min-gradient elution to avoid interference from baicalin isomers and their in-source dissociation. Excellent linearity was observed over the concentration ranges of 5.00-2000 ng/ml for baicalin and 1.00-100 ng/ml for baicalein. The validated method was successfully applied to a pharmacokinetic study of an oral administration of 60 ml Shuanghuanglian in healthy subjects. This study provided a foundation to investigate the clinical efficacy and safety of Shuanghuanglian further.

Development and application of an uncapped mRNA platform

A novel uncapped mRNA platform was developed. Five lipid nanoparticle (LNP)-encapsulated mRNA constructs were made to evaluate several aspects of our platform, including transfection efficiency and durability in vitro and in vivo and the activation of humoral and cellular immunity in several animal models. The constructs were eGFP-mRNA-LNP (for enhanced green fluorescence mRNA), Fluc-mRNA-LNP (for firefly luciferase mRNA), S{delta}T-mRNA-LNP (for Delta strain SARS-CoV-2 spike protein trimer mRNA), gDED-mRNA-LNP (for truncated glycoprotein D mRNA coding ectodomain from herpes simplex virus type 2 (HSV2)) and gDFR-mRNA-LNP (for truncated HSV2 glycoprotein D mRNA coding amino acids 1~400). Quantifiable target protein expression was achieved in vitro and in vivo with eGFP- and Fluc-mRNA-LNP. S{delta}T-mRNA-LNP, gDED-mRNA-LNP and gDFR-mRNA-LNP induced both humoral and cellular immune responses comparable to those obtained by previously reported capped mRNA-LNP constructs. Notably, 25, 50 and 100 g of S{delta}T-mRNA-LNP all elicited neutralizing antibodies in hamsters against the Omicron and Delta strains. Additionally, gDED-mRNA-LNP and gDFR-mRNA-LNP induced potent neutralizing antibodies in rabbits and mice. The mRNA constructs with uridine triphosphate (UTP) outperformed those with N1-methylpseudouridine triphosphate (N1m{psi}TP) in the in vivo expression of luciferase and the induction of antibodies via S{delta}T-mRNA-LNP. Our uncapped, process-simplified, and economical mRNA platform may have broad utility in vaccines and protein replacement drugs.

What catalyzes the proactive recovery of peasants from the COVID-19 pandemic? A livelihood perspective in Ningqiang County, China.

The livelihood recovery strategy is utilized for peasants during the COVID-19 pandemic. This strategy serves a salient role to help them recover from the relevant hazardous impacts. Disaster risk has been a major concern among hazards for the increasing likelihood of exposure and vulnerability, especially in the process of poverty alleviation in China. However, few studies have discussed the factors and mechanisms that influence peasants to adopt livelihood recovery strategies in the context of the COVID-19 pandemic in China. Based on a case study of Ningqiang County, China, this study explores the mechanisms that catalyze the proactive recovery of peasants from the COVID-19 pandemic from a livelihood perspective. Methodologically, the study proposes a framework that integrates the modified pressure-state-response (PSR) framework and the sustainable livelihoods approach (SLA), and it employs structure equation modeling (SEM) approach to examine how specific factors affect peasants to proactively adopt livelihood strategies to recover from the COVID-19 pandemic. The results indicate that the COVID-19 pressure significantly increases the risk perception of peasants and decreases their livelihood capital. Further, the decreased livelihood capital, the improvement of risk perception and supportive policy will promote peasants to adopt livelihood recovery strategies. Moreover, the results specify that risk perception and supportive policy mediate the relation between livelihood capital and recovery strategy. The findings will be beneficial for policymakers and researchers to understand the mechanisms that peasants adopt livelihood strategies to recover from disasters, and can serve as references for formulating disaster risk reduction and resilience policies.

CD31 and D2-40 Contribute to Peritoneal Metastasis of Colorectal Cancer by Promoting Epithelial-Mesenchymal Transition

Background/Aims@#Colorectal cancer (CRC) patients often exhibit peritoneal metastasis, which negatively impacts their prognosis. CD31 and D2-40 have recently been suggested to be predictors of breast cancer prognosis, but their role in colorectal peritoneal metastasis (CRPM) remains unknown. @*Methods@#The expression profiles of CD31 and D2-40 were analyzed in CRC patients with or without CRPM and in CRC cell lines with increasing metastatic potential. Overexpression and short hairpin RNA knockdown assays were performed in CRC cells, and the effects of these alterations on epithelial-mesenchymal transition (EMT) in vitro, growth of xenograft tumors in vivo, and peritoneal metastasis potential in a mouse model of CRPM were examined. @*Results@#The expressions of CD31 and D2-40 were upregulated in CRC tumor tissues and was elevated further in tumor tissues from patients with CRPM. CD31 and D2-40 expression levels exhibited increasing trends parallel to the EMT potential of CRC cells. CD31 and D2-40 are essential for CRC cell EMT in vitro as well as for xenograft tumor growth and peritoneal metastasis in vivo. @*Conclusions@#CD31 and D2-40 contribute to CRPM by promoting EMT and may serve as prognostic markers and therapeutic targets for CRC, particularly in patients with peritoneal metastasis.

Effects of FoxO1 on FoxO1-KLF2-S1P1 pathway in Jurkat cells / 中国免疫学杂志

To observe the contribution of FoxO1 on its downstream molecules expression and function in Jurkat cells,Jurkat cells were infected with FoxO1 expression lentivirus and interference lentivirus to establish FoxO1-KLF2-S1P1 signaling pathways mod-el.After infection of 120 h,FoxO1,KLF2,S1P1 and CD62L mRNA levels and the protein expression of FoxO1,FoxO1-p and KLF2 were increased (P<0.05) in FoxO1-overexpression group.Converse results(P<0.05) were observed in the interference group.The proportions of S1P1+cells were increased in both groups.It was notably that S1P1+cells were decreased(P<0.05) in interference group after infection of 72 h.The proportion of CD62L+cells was increased(P<0.05) in overexpression group,it was decreased(P<0.05) in the interference group.This vitro experiments showed S1P1 and CD62L could be regulated by FoxO1 lentivirus,and provided an experimental basis for research about intracellular FoxO1-KLF2-S1P1 signaling pathways and cellular functions.

Disruption of putrescine biosynthesis in Shewanella oneidensis enhances biofilm cohesiveness and performance in Cr(VI) immobilization.

Although biofilm-based bioprocesses have been increasingly used in various applications, the long-term robust and efficient biofilm performance remains one of the main bottlenecks. In this study, we demonstrated that biofilm cohesiveness and performance of Shewanella oneidensis can be enhanced through disrupting putrescine biosynthesis. Through random transposon mutagenesis library screening, one hyperadherent mutant strain, CP2-1-S1, exhibiting an enhanced capability in biofilm formation, was obtained. Comparative analysis of the performance of biofilms formed by S. oneidensis MR-1 wild type (WT) and CP2-1-S1 in removing dichromate (Cr2O7(2-)), i.e., Cr(VI), from the aqueous phase showed that, compared with the WT biofilms, CP2-1-S1 biofilms displayed a substantially lower rate of cell detachment upon exposure to Cr(VI), suggesting a higher cohesiveness of the mutant biofilms. In addition, the amount of Cr(III) immobilized by CP2-1-S1 biofilms was much larger, indicating an enhanced performance in Cr(VI) bioremediation. We further showed that speF, a putrescine biosynthesis gene, was disrupted in CP2-1-S1 and that the biofilm phenotypes could be restored by both genetic and chemical complementations. Our results also demonstrated an important role of putrescine in mediating matrix disassembly in S. oneidensis biofilms.

Improvement of plant growth and seed yield in Jatropha curcas by a novel nitrogen-fixing root associated Enterobacter species.

BACKGROUND: Jatropha curcas L. is an oil seed producing non-leguminous tropical shrub that has good potential to be a fuel plant that can be cultivated on marginal land. Due to the low nutrient content of the targeted plantation area, the requirement for fertilizer is expected to be higher than other plants. This factor severely affects the commercial viability of J. curcas. RESULTS: We explored the feasibility to use endophytic nitrogen-fixing bacteria that are native to J. curcas to improve plant growth, biomass and seed productivity. We demonstrated that a novel N-fixing endophyte, Enterobacter sp. R4-368, was able to colonize in root and stem tissues and significantly promoted early plant growth and seed productivity of J. curcas in sterilized and non-sterilized soil. Inoculation of young seedling led to an approximately 57.2% increase in seedling vigour over a six week period. At 90 days after planting, inoculated plants showed an average increase of 25.3%, 77.7%, 27.5%, 45.8% in plant height, leaf number, chlorophyll content and stem volume, respectively. Notably, inoculation of the strain led to a 49.0% increase in the average seed number per plant and 20% increase in the average single seed weight when plants were maintained for 1.5 years in non-sterilized soil in pots in the open air. Enterobacter sp. R4-368 cells were able to colonize root tissues and moved systemically to stem tissues. However, no bacteria were found in leaves. Promotion of plant growth and leaf nitrogen content by the strain was partially lost in nifH, nifD, nifK knockout mutants, suggesting the presence of other growth promoting factors that are associated with this bacterium strain. CONCLUSION: Our results showed that Enterobacter sp. R4-368 significantly promoted growth and seed yield of J. curcas. The application of the strains is likely to significantly improve the commercial viability of J. curcas due to the reduced fertilizer cost and improved oil yield.

Complete Genome Sequence of Enterobacter sp. Strain R4-368, an Endophytic N-Fixing Gammaproteobacterium Isolated from Surface-Sterilized Roots of Jatropha curcas L.

Enterobacter sp. strain R4-368 is one of the few characterized Jatropha endophytic diazotrophic bacteria and was isolated from surface-sterilized roots. This bacterium shows strong growth-promoting effects, being able to increase plant biomass and seed yields. Enterobacter sp. R4-368 is the second fully sequenced diazotrophic Enterobacter species. The sequence information shall facilitate the elucidation of the molecular mechanisms of plant growth promotion, nitrogen fixation in nonlegume plant species, and evolution of biological nitrogen fixation systems.

Characterization of glyceraldehyde-3-phosphate dehydrogenase gene RtGPD1 and development of genetic transformation method by dominant selection in oleaginous yeast Rhodosporidium toruloides.

The oleaginous yeast Rhodosporidium toruloides, which belongs to the Pucciniomycotina subphylum in the Basidiomycota, has attracted strong interest in the biofuel community recently due to its ability to accumulate more than 60% of dry biomass as lipid under high-density fermentation. A 3,543-nucleotide (nt) DNA fragment of the glyceraldehyde-3-phosphate dehydrogenase gene (GPD1) was isolated from R. toruloides ATCC 10657 and characterized in details. The 1,038-nt mRNA derived from seven exons encodes an open reading frame (ORF) of 345 amino acids that shows high identity (80%) to the Ustilago maydis homolog. Notably, the ORF is composed of codons strongly biased towards cytosine at the Wobble position. GPD1 is transcriptionally regulated by temperature shock, osmotic stress, and carbon source. Nested deletion analysis of the GPD1 promoter by GFP reporter assay revealed that two regions, -975 to -1,270 and -1,270 to -1,429, upstream from the translational start site of GPD1 were important for responses to various stress stimuli. Interestingly, a 176-bp short fragment maintained 42.2% promoter activity of the 795-bp version in U. maydis whereas it was reduced to 17.4% in R. toruloides. The GPD1 promoter drove strong expression of a codon-optimized enhanced green fluorescent protein gene (RtGFP) and a codon-optimized hygromycin phosphotransferase gene (hpt-3), which was critical for Agrobacterium tumefaciens-mediated transformation in R. toruloides.