Dietary Recombinant Phycoerythrin Modulates the Gut Microbiota of H22 Tumor-Bearing Mice.

Hongtao Qi,Xin Qi,Huaxin Chen,Hui Liang,Peng Jiang,Dongfeng Wang,Ying Liu

doi:10.3390/md17120665

Abstract

Normal intestinal flora is widely involved in many functions of the host: nutritional metabolism; maintenance of intestinal microecological balance; regulation of intestinal endocrine function and nerve signal transduction; promotion of intestinal immune system development and maturation; inhibition of pathogenic bacteria growth and colonization, reduction of its invasion to intestinal mucosa, and so on. In recent years, more and more studies have shown that intestinal flora is closely related to the occurrence, development, and treatment of various tumors. It is indicated that recombinant phycoerythrin (RPE) has significant anti-tumor and immunomodulatory effects. However, little is known about the mechanism of the effect of oral (or intragastric) administration of RPE on gut microbiota in tumor-bearing animals. In this study, using high-throughput 16S rDNA sequencing, we examined the response of gut microbiota in H22-bearing mice to dietary RPE supplementation. The results showed that the abundance of beneficial bacteria in the mice intestinal flora decreased and that of the detrimental flora increased after inoculation with tumor cells (H22); following treatment with dietary RPE, the abundance of beneficial bacteria in the intestinal flora significantly increased and that of detrimental bacteria decreased. In this study, for the first time, it was demonstrated that dietary RPE could modulate the gut microbiota of the H22 bearing mice by increasing the abundance of beneficial bacteria and decreasing that of detrimental bacteria among intestinal bacteria, providing evidence for the mechanism by which bioactive proteins affect intestinal nutrition and disease resistance in animals.

Highlights

Phycobiliproteins are light-harvesting chromoproteins found in red algae, blue-green algae, Cryptophyta, and a few dinoflagellates, and include phycoerythrin (PE), phycoerythrocyanin (PEC), phycocyanin (PC), and allophycocyanin (APC) [1]
Mice in the (B), (C), and (D) groups were subcutaneously inoculated with H22 tumor cells, and (B) and (C) were treated by intragastrical (i.g.) administration of physiological saline and recombinant phycoerythrin (RPE) solution, respectively; (D) was received intraperitoneal (i.p.) injection with cyclophosphamide (CP) as a positive drug control
By the analysis of alpha diversity, during the selected experimental period, there was no significant difference in the composition of bacterial flora; it can be concluded that the structure of gut microbiota among the four groups of mice was relatively stable

Summary

Introduction

Phycobiliproteins are light-harvesting chromoproteins found in red algae, blue-green algae, Cryptophyta, and a few dinoflagellates, and include phycoerythrin (PE), phycoerythrocyanin (PEC), phycocyanin (PC), and allophycocyanin (APC) [1]. Phycobiliproteins are a type of protein, and excellent natural edible pigments [2]. They have many biological functions, such as anti-cancer [3], anti-inflammatory, and anti-oxidation [4,5]. They can improve lymphocyte activity and enhance immunity [6]. The direct extraction of phycobiliprotein from various algae is the main method for obtaining the protein. The extraction from natural algae is very complex and expensive [7], and these difficult-to-extract phycobiliproteins have lower activity. The phycobiliprotein used in this study was recombinant phycoerythrin (RPE)

Methods

Results

Discussion

Conclusion