With the support of modern biotechnology, vaccine technology continues to iterate. The safety and efficacy of vaccines are some of the most important areas of development in the field. As a natural substance, chitosan is widely used in numerous fields—such as immune stimulation, drug delivery, wound healing, and antibacterial procedures—due to its good biocompatibility, low toxicity, biodegradability, and adhesion. Chitosan-based nanoparticles (NPs) have attracted extensive attention with respect to vaccine adjuvants and delivery systems due to their excellent properties, which can effectively enhance immune responses. Here, we list the classifications and mechanisms of action of vaccine adjuvants. At the same time, the preparation methods of chitosan, its NPs, and their mechanism of action in the delivery system are introduced. The extensive applications of chitosan and its NPs in protein vaccines and nucleic acid vaccines are also introduced. This paper reviewed the latest research progress of chitosan-based NPs in vaccine adjuvant and drug delivery systems.

Background: Growing evidence suggests the gut microbiota and metabolites in serum or fecal may play a key role in the process of alcohol use disorder (AUD). However, the correlations of gut microbiota and metabolites in both feces and serum in AUD subjects are not well understood.Methods: We established a rat model of AUD by a chronic intermittent ethanol voluntary drinking procedure, then the AUD syndromes, the gut microbiota, metabolomic profiling in feces and serum of the rats were examined, and correlations between gut microbiota and metabolites were analyzed.Results: Ethanol intake preference increased and maintained at a high level in experimental rats. Anxiety-like behaviors was observed by open field test and elevated plus maze test after ethanol withdraw, indicating that the AUD rat model was successfully developed. The full length 16S rRNA gene sequencing showed AUD significantly changed the β-diversity of gut microbial communities, and significantly decreased the microbial diversity but did not distinctly impact the microbial richness. Microbiota composition significantly changed in AUD rats, such as the abundance of Romboutsia and Turicibacter were significantly increased, whereas uncultured_bacterium_o_Mollicutes_RF39 was decreased. In addition, the untargeted metabolome analysis revealed that many metabolites in both feces and serum were altered in the AUD rats, especially involved in sphingolipid metabolism and glycerophospholipid metabolism pathways. Finally, multiple correlations among AUD behavior, gut microbiota and co-changed metabolites were identified, and the metabolites were directly correlated with the gut microbiota and alcohol preference.Conclusion: The altered metabolites in feces and serum are important links between the gut microbiota dysbiosis and alcohol preference in AUD rats, and the altered gut microbiota and metabolites can be potentially new targets for treating AUD.

Physalis alkekengi L. calyx (PC) extract can relieve insulin resistance and has glycemic and anti-inflammatory effects; however, the potential mechanisms related to gut microbiota and metabolites remain elusive. This study aimed to understand how PC regulates gut microbiota and metabolites to exert anti-obesogenic effects and relieve insulin resistance. In this study, a high-fat high-fructose (HFHF)-diet-induced obesity C57BL/6J male mice model with glycolipid metabolism dysfunction was established, which was supplemented with the aqueous extract of PC daily for 10 weeks. The results showed that the PC supplementation could effectively cure the abnormal lipid metabolism and maintain glucose metabolism homeostasis by regulating the expression of adipose metabolic genes and glucose metabolism genes in the liver, thereby effectively alleviating the inflammatory response. PC treatment also increased the contents of fecal short-chain fatty acids (SCFAs), especially butyric acid. PC extract could restore the HFHF-disrupted diversity of gut microbiota by significantly increasing the relative abundance of Lactobacillus and decreasing those of Romboutsia, Candidatus_Saccharimonas, and Clostridium_sensu_stricto_1. The negative effects of the HFHF diet were ameliorated by PC by regulating multiple metabolic pathways, such as lipid metabolism (linoleic acid metabolism, alpha-linolenic acid metabolism, and sphingolipid metabolism) and amino acid metabolism (histidine and tryptophan metabolism). Correlation analysis showed that among the obesity parameters, gut microbiota and metabolites are directly and closely related. To sum up, this study suggested that PC treatment exhibited therapeutic effects by regulating the gut microbiota, fecal metabolites, and gene expression in the liver to improve glucose metabolism, modulate adiposity, and reduce inflammation.

Ginsenoside Rh2 has been shown to have an anti-tumor effect on a wide range of cancers. A previous study has shown that ginsenoside Rh2 can inhibit the proliferation of the human lung adenocarcinoma A549 cell line in a dose-dependent manner by activating caspase-8/3 activity to promote apoptosis. However, the association of the JNK signaling pathways and transcription factors with ginsenoside Rh2 in the suppression of non-small cell lung cancer has not yet been reported. In this study, we found that ginsenoside Rh2 can activate the JNK/MAPKs signaling pathway and increase the phosphorylation and transcriptional activity of the transcription factors AP-1 and ATF2. Ginsenoside Rh2 also reduced the expression of transcription factors E2F1 and c-Myc. Furthermore, ginsenoside Rh2 affected the expression levels of cyclin D1 and the CDK4 protein, which are key regulatory factors of the G1/S cyclin-dependent kinase. The anti-proliferative and induced apoptotic effects of ginsenoside Rh2 on A549 cell provide evidence to support the application of traditional Chinese medicine to lung cancer treatment.