The intestinal microenvironment shapes macrophage and dendritic cell identity and function

The interactions between the host immunity and intestinal microorganisms in fish

There is a huge quantity of microorganisms in the gut of fish, which exert pivotal roles in maintaining host intestinal and general health. The fish immunity can sense and shape the intestinal microbiota and maintain the intestinal homeostasis. In the meantime, the intestinal commensal microbes regulate the fish immunity, control the extravagant proliferation of pathogenic microorganisms, and ensure the intestinal health of the host. This review summarizes developments and progress on the known interactions between host immunity and intestinal microorganisms in fish, focusing on the recent advances in zebrafish (Danio rerio) showing the host immunity senses and shapes intestinal microbiota, and intestinal microorganisms tune host immunity. This review will offer theoretical references for the development, application, and commercialization of intestinal functional microorganisms in fish. KEY POINTS: • The interactions between the intestinal microorganisms and host immunity in zebrafish • Fish immunity senses and shapes the microbiota • Intestinal microbes tune host immunity in fish.

Differential regulation of lung homeostasis and silicosis by the TAM receptors MerTk and Axl

Introduction

TAM receptor-mediated efferocytosis plays an important function in immune regulation and may contribute to antigen tolerance in the lungs, a site with continuous cellular turnover and generation of apoptotic cells. Some studies have identified failures in efferocytosis as a common driver of inflammation and tissue destruction in lung diseases. Our study is the first to characterize the in vivo function of the TAM receptors, Axl and MerTk, in the innate immune cell compartment, cytokine and chemokine production, as well as the alveolar macrophage (AM) phenotype in different settings in the airways and lung parenchyma.

Methods

We employed MerTk and Axl defective mice to induce acute silicosis by a single exposure to crystalline silica particles (20 mg/50 μL). Although both mRNA levels of Axl and MerTk receptors were constitutively expressed by lung cells and isolated AMs, we found that MerTk was critical for maintaining lung homeostasis, whereas Axl played a role in the regulation of silica-induced inflammation. Our findings imply that MerTk and Axl differently modulated inflammatory tone via AM and neutrophil recruitment, phenotype and function by flow cytometry, and TGF-β and CXCL1 protein levels, respectively. Finally, Axl expression was upregulated in both MerTk-/- and WT AMs, confirming its importance during inflammation.

Conclusion

This study provides strong evidence that MerTk and Axl are specialized to orchestrate apoptotic cell clearance across different circumstances and may have important implications for the understanding of pulmonary inflammatory disorders as well as for the development of new approaches to therapy.

Yupingfeng polysaccharide promote the growth of chickens via regulating gut microbiota

Introduction

Yupingfeng polysaccharide (YPF-P) is the main substance of alcohol deposition in Yupingfeng powder, which has many biological functions such as enhancing immunity, repairing intestinal barrier and enhancing antioxidant ability. This study employed in vitro growth-promoting drug feed additives and animal experiments to comprehensively evaluate the use of YPF-P in broiler production.

Methods

A total of 1,296 151 days-old Qingyuan Partridge chickens were randomly divided into four groups with six replicates and 54 hens per replicate: the control group was fed basal diet, and the experimental groups were fed diets supplemented with 4 g/kg, 8 g/kg, and 12 g/kg YPF-P for 14 days. Broilers were weighed before and at the end of the experiment to calculate total weight gain (GW), average daily gain (ADG), and feed compensation. At the end of the experiment, six chickens from each group were randomly selected for subwing vein blood sampling, which was used to measure serum biochemical indicators GHRH, GH, and IGF-1 by ELISA method. Randomly select chickens from control group and 8 g/kg group for slaughter, and cecal contents were collected for 16S high-throughput sequencing.

Results

Dietary supplementation of 8 g/kg YPF-P can significantly increase the final body weight, total weight gain, average daily gain and decrease the feed to gain ratio of chickens. During 151-165 days, serum IGF-1 concentrations increased significantly (p < 0.05). There were no significant changes in serum GH concentration (p > 0.05). In terms of gut microbiota, there was no significant difference between control group and test group in Shannon index and Simpson index. Compared with the control group,the addition of 8 g/kgYPF-P significantly increased the abundance of Firmicutes and significantly decreased the abundance of Bacteroides at the phylum level.At the genus level, the relative abundance of unclassified_Oscillospiraceae was significantly increased and the unclassified_Muribaculaceae, uncultured_Bacteroidales_bacterium, Lactobacillus, Alloprevotella, Ligilactobacillus, Prevotellaceae_UCG_001, and unclassified_Atopobiaceae was significantly decreased.

Conclusion

The above results showed that adding 8 mg/kg of YPF-P could increase the average daily gain of Qingyuan Partridge chickens, reduce the ratio of feed to meat, and affect the distribution proportion of intestinal microflora in chickens to some extent.

Building better barriers: how nutrition and undernutrition impact pediatric intestinal health

Chronic undernutrition is a major cause of death for children under five, leaving survivors at risk for adverse long-term consequences. This review focuses on the role of nutrients in normal intestinal development and function, from the intestinal epithelium, to the closely-associated mucosal immune system and intestinal microbiota. We examine what is known about the impacts of undernutrition on intestinal physiology, with focus again on the same systems. We provide a discussion of existing animal models of undernutrition, and review the evidence demonstrating that correcting undernutrition alone does not fully ameliorate effects on intestinal function, the microbiome, or growth. We review efforts to treat undernutrition that incorporate data indicating that improved recovery is possible with interventions focused not only on delivery of sufficient energy, macronutrients, and micronutrients, but also on efforts to correct the abnormal intestinal microbiome that is a consequence of undernutrition. Understanding of the role of the intestinal microbiome in the undernourished state and correction of the phenotype is both complex and a subject that holds great potential to improve recovery. We conclude with critical unanswered questions in the field, including the need for greater mechanistic research, improved models for the impacts of undernourishment, and new interventions that incorporate recent research gains. This review highlights the importance of understanding the mechanistic effects of undernutrition on the intestinal ecosystem to better treat and improve long-term outcomes for survivors.