Robust microbe immune recognition in the intestinal mucosa

Challenges and opportunities in the development of mucosal mRNA vaccines

mRNA vaccines have played a critical role in controlling the SARS-CoV-2 pandemic, and are being actively studied for use in other diseases. There is a growing interest in applying mRNA vaccines at mucosal surfaces as it enables access to a unique immune reservoir in a less-invasive manner. However, mucosal surfaces present several barriers to mRNA uptake, including degrading enzymes, mucus, and clearance mechanisms. In this mini-review, we discuss our understanding of the immune response to mucosal mRNA vaccines as it compares to systemic mRNA vaccines. We also highlight physical and chemical methods for enhancing mRNA uptake across mucosal tissues. Mucosal mRNA vaccination is a nascent field of research, which will greatly benefit from fundamental investigations into the mechanisms of immune activation and the development of technologies for improved delivery.

The process of hypertension induced by high-salt diet: Association with interactions between intestinal mucosal microbiota, and chronic low-grade inflammation, end-organ damage

Inflammation and immunity play a major role in the development of hypertension, and a potential correlation between host mucosal immunity and inflammatory response regulation. We explored the changes of intestinal mucosal microbiota in hypertensive rats induced by high-salt diet and the potential link between the intestinal mucosal microbiota and inflammation in rats. Therefore, we used PacBio (Pacific Bioscience) SMRT sequencing technology to determine the structure of intestinal mucosal microbiota, used enzyme-linked immunosorbent assay (ELISA) to determined the proinflammatory cytokines and hormones associated with hypertension in serum, and used histopathology methods to observe the kidney and vascular structure. We performed a potential association analysis between intestinal mucosal characteristic bacteria and significantly different blood cytokines in hypertensive rats induced by high-salt. The results showed that the kidney and vascular structures of hypertensive rats induced by high salt were damaged, the serum concentration of necrosis factor-α (TNF-α), angiotensin II (AngII), interleukin-6 (IL-6), and interleukin-8 (IL-8) were significantly increased (p < 0.05), and the coefficient of immune organ spleen was significantly changed (p < 0.05), but there was no significant change in serum lipids (p > 0.05). From the perspective of gut microbiota, high-salt diet leads to significant changes in intestinal mucosal microbiota. Bifidobacterium animalis subsp. and Brachybacterium paraconglomeratum were the dominant differential bacteria in intestinal mucosal, with the AUC (area under curve) value of Bifidobacterium animalis subsp. and Brachybacterium paraconglomeratum were 1 and 0.875 according to ROC (receiver operating characteristic) analysis. Correlation analysis showed that Bifidobacterium animalis subsp. was correlated with IL-6, IL-8, TNF-α, and Ang II. Based on our results, we can speculated that high salt diet mediated chronic low-grade inflammation through inhibited the growth of Bifidobacterium animalis subsp. in intestinal mucosa and caused end-organ damage, which leads to hypertension.

Microbiota medicine: towards clinical revolution

The human gastrointestinal tract is inhabited by the largest microbial community within the human body consisting of trillions of microbes called gut microbiota. The normal flora is the site of many physiological functions such as enhancing the host immunity, participating in the nutrient absorption and protecting the body against pathogenic microorganisms. Numerous investigations showed a bidirectional interplay between gut microbiota and many organs within the human body such as the intestines, the lungs, the brain, and the skin. Large body of evidence demonstrated, more than a decade ago, that the gut microbial alteration is a key factor in the pathogenesis of many local and systemic disorders. In this regard, a deep understanding of the mechanisms involved in the gut microbial symbiosis/dysbiosis is crucial for the clinical and health field. We review the most recent studies on the involvement of gut microbiota in the pathogenesis of many diseases. We also elaborate the different strategies used to manipulate the gut microbiota in the prevention and treatment of disorders. The future of medicine is strongly related to the quality of our microbiota. Targeting microbiota dysbiosis will be a huge challenge.