Abstract
Background: Exosomes are extracellular membranous nanovesicles that carry functional molecules, such as proteins, to mediate local and systemic cell-to-cell communication. Exosomes released by cells can present in the plasma and involved in the regulation of immunity. Probiotics play a beneficial role in improving the immune function of host through many mechanisms. However, whether probiotics can increase the immune function of broilers by regulating plasmal exosomal cargo is unclear. Methods: Three hundred broilers were allocated to three treatments: control diet (CON group), control diet + dexamethasone (DEX) injection (DEX group), control diet containing 1 × 108 cfu/g Lactobacillus plantarum P8 + DEX injection (P8+DEX group). The immune function of broilers was detected by measuring the levels of inflammatory cytokines and immunoglobulins in plasma and jejunal mucosa. Exosomes were isolated from the plasma via EIQ3 isolation kits and characterized via transmission electron microscopy, nanoparticle tracking analysis, and Western blot. Then, exosomal protein profile was determined by proteomic. At last, correlation analysis was performed to figure out the potential role of exosomal proteins in regulating immune function of P8-treated broilers.Results: P8+DEX treatment improved the immune function of DEX-induced immunosuppressive broiler through decreasing plasmal IL-1β, IL-6, TNF-α and jejunal IL-1β, as well as increasing plasmal IL-10 and jejunal IgM. The isolated extracellular vesicles had an average diameter of 125.8 nm, exhibited a cup-shaped morphology and expressed exosomal markers. A total of 784 proteins were identified in the exosomes. Among the 784 proteins, 126 differentially expressed proteins (DEPs) were found between DEX and CON groups, 102 DEPs were found between P8+DEX and DEX groups. Gene Ontology analysis indicated that DEPs between DEX and CON groups are mainly involved in metabolic process, cellular anatomical entity, cytoplasm, extracellular region and binding. DEPs between P8+DEX and DEX are mainly involved in multicellular organismal process, response to stimulus, cytoplasm, cell periphery, membrane, binding, protein binding and ion binding. Further, pathway analysis revealed that most of the DEPs between DEX and CON participated in the ECM-receptor interaction, focal adhesion, regulation of actin cytoskeleton, endocytosis and phagosome. Most of the DEPs between P8+DEX and DEX participated in the ErbB and PPAR signaling pathways. Moreover, many immunity-related DEPs were correlated with the altered immune parameters in plasma and jejunal in broilers fed with P8.Conclusions: Our findings demonstrated that plasmal exosomes in immunosuppressive broilers fed with P8 carry proteins related to immune function, and may have immunomodulatory effects on the plasma and intestinal immunity.
Effect of Amaranth and Quinoa Flours on Exopolysaccharide Production and Protein Profile of Liquid Sourdough Fermented by Weissella cibaria and Lactobacillus plantarum