Portulaca oleracea L. polysaccharide alleviates dextran sulfate sodium-induced ulcerative colitis by regulating intestinal homeostasis.

Portulaca oleracea L. (purslane) is a vegetable that contains a variety of active compounds with nutritional properties and has the potential to treat ulcerative colitis (UC). However, the mechanisms underlying the effects of Portulaca oleracea L. polysaccharide (POP) in alleviating UC remain unclear. In this study, we prepared an aqueous extract of purslane and separated a fraction with molecular weight >10 kDa using membrane separation. This fraction was used to isolate POP. The effect of POP on gut microbiota and colon transcriptome in dextran sulfate sodium-induced UC model mice was evaluated. POP treatment reduced inflammation and oxidative stress imbalance in UC mice. In addition, POP improved the intestinal barrier and regulated intestinal homeostasis. Importantly, POP was found to regulate gut microbiota, maintain the levels of retinol and short-chain fatty acids in the gut, promote the proliferation and differentiation of B cells in the colon, and increase the expression of immunoglobulin A. These results provide novel insights into the role of POP in regulating intestinal homeostasis, which should guide further development of POP as a functional food.

Lysimachia christinae polysaccharide attenuates diet-induced hyperlipidemia via modulating gut microbes-mediated FXR-FGF15 signaling pathway.

Polysaccharides are one of the most abundant and active components of Lysimachia christinae (L. christinae), which is widely adopted for attenuating abnormal cholesterol metabolism; however, its mechanism of action remains unclear. Therefore, we fed a natural polysaccharide (NP) purified from L. christinae to high-fat diet mice. These mice showed an altered gut microbiota and bile acid pool, which was characterized by significantly increased Lactobacillus murinus and unconjugated bile acids in the ileum. Oral administration of the NP reduced cholesterol and triglyceride levels and enhanced bile acid synthesis via cholesterol 7α-hydroxylase. Additionally, the effects of NP are microbiota-dependent, which was reconfirmed by fecal microbiota transplantation (FMT). Altered gut microbiota reshaped bile acid metabolism by modulating bile salt hydrolase (BSH) activity. Therefore, bsh genes were genetically engineered into Brevibacillus choshinensis, which was gavaged into mice to verify BSH function in vivo. Finally, adeno-associated-virus-2-mediated overexpression or inhibition of fibroblast growth factor 15 (FGF15) was used to explore the farnesoid X receptor-fibroblast growth factor 15 pathway in hyperlipidemic mice. We identified that the NP relieves hyperlipidemia by altering the gut microbiota, which is accompanied by the active conversion of cholesterol to bile acids.

Expression and immunogenicity of hepatitis E virus-like particles based on recombinant truncated ORF2 capsid protein.

Hepatitis E is an emerging zoonotic disease, posing a severe threat to public health in the world. Since there are no specific treatments available for HEV infection, it is crucial to develop vaccine to prevent this infection. In this study, the truncated ORF2 encoded protein of 439aa∼617aa (HEV3-179) from HEV CCJD-517 isolates was expressed as VLPs in E. coli with diameters of approximate 20 nm. HEV3-179 protein was immunized with mice, and the results showed that a higher titre of antibody was induced in NIH mice in comparison with that of KM mice (P < 0.01) and BALB/c mice (P < 0.01). The induced antibody titer is much higher in subcutaneous immunization mice than that in the mice inoculated via abdominal immunization (P < 0.05) and muscles immunization (P < 0.01). Mice immunized with 12 µg and 6 µg candidate vaccine induced higher level of antibody titer than that of 3 µg dosage group (P < 0.01, P < 0.05). Antibody change curve showed that HEV IgG antibody titer increased from 14 days post immunization (dpi) to 1:262144 and reached the peak level on 42 dpi before gradually retreated with the same level antibody titer with 1:131072 until 84 dpi. Mice inoculated with HEV3-179 produced higher titer of cytokines than the mock group, and the concentration of IL-1ß (P < 0.01) and IFN-γ (P < 0.01) further increased after stimulated by candidate vaccine. The result indicated that HEV3-179 possesses good immunogenicity, which could be used as a potential candidate for future HEV vaccine development.

Construction of A375·S2 Melanoma Cell Line with High Sensibility to IL-1 by Overexpressing IL-1 Receptor.

We described an operation that co-overexpress interleukin receptor 1 (IL-1R1) and its co-receptor (IL-1R1AcP) genes in wild-type A375·S2 cells in order to increase their sensibility to IL-1. Firstly, laser scanning confocal microscope observed that IL-1R1 could be expressed on the surface of A375·S2 cells. qPCR was performed to estimate the ratio of two genes and result showed the ratio was almost 4.57:1. Then two genes were linked to vectors and co-transfected into A375·S2 cells. qPCR and Western blotting showed the protein content improved markedly. Finally, MTS assay was executed and the sensitivity of A375·S2 cells that co-transfected receptors to IL-1ß increased significantly. Another MTS assay showed the cell activity variation changed significantly (P < 0.05) and the reliability of the experiment was high, indicating that cell line established in this study could be further used for the activity test of IL-1Ra. Supplementary Information: The online version contains supplementary material available at 10.1007/s12088-022-01027-8.

Expression and Immunogenicity of SARS-CoV-2 Virus-Like Particles based on Recombinant Truncated HEV-3 ORF2 Capsid Protein.

COVID-19 is an emerging disease that poses a severe threat to global public health. As such, there is an urgent demand for vaccines against SARS-CoV-2, the virus that causes COVID-19. Here, we describe a virus-like nanoparticle candidate vaccine against SARS-CoV-2 produced by an E. coli expression system. The fusion protein of a truncated ORF2-encoded protein of aa 439~608 (p170) from hepatitis E virus CCJD-517 and the receptor-binding domain of the spike protein from SARS-CoV-2 were expressed, purified and characterized. The antigenicity and immunogenicity of p170-RBD were evaluated in vitro and in Kunming mice. Our investigation revealed that p170-RBD self-assembled into approximately 24 nm virus-like particles, which could bind to serum from vaccinated people (p < 0.001) and receptors on cells. Immunization with p170-RBD induced the titer of IgG antibody vaccine increased from 14 days post-immunization and was significantly enhanced after a booster immunization at 28 dpi, ultimately reaching a peak level on 42 dpi with a titer of 4.97 log10. Pseudovirus neutralization tests showed that the candidate vaccine induced a strong neutralizing antibody response in mice. In this research, we demonstrated that p170-RBD possesses strong antigenicity and immunogenicity and could be a potential candidate for use in future SARS-CoV-2 vaccine development.