Lipopolysaccharide (LPS) is a bacterial endotoxin that induces intestine inflammation. Milk exosomes improve the intestine and immune system development of newborns. This study aims to establish the protective mechanisms of porcine milk exosomes on the attenuation of LPS-induced intestinal inflammation and apoptosis. In vivo, exosomes prevented LPSinduced intestine damage and inhibited (p < 0.05) LPS-induced inflammation. In vitro, exosomes inhibited (p < 0.05) LPSinduced intestinal epithelial cells apoptosis (23% ± 0.4% to 12% ± 0.2%). Porcine milk exosomes also decreased (p < 0.05) the LPS-induced TLR4/NF-κB signaling pathway activation. Furthermore, exosome miR-4334 and miR-219 reduced (p < 0.05) LPS-induced inflammation through the NF-κB pathway and miR-338 inhibited (p < 0.05) the LPS-induced apoptosis via the p53 pathway. Cotransfection with these three miRNAs more effectively prevented (p < 0.05) LPS-induced cell apoptosis than these miRNAs individual transfection. The apoptosis percentage in the group cotransfected with the three miRNAs (14% ± 0.4%) was lower (p < 0.05) than that in the NC miRNA group (28% ± 0.5%), and also lower than that in each individual miRNA group. In conclusion, porcine milk exosomes protect the intestine epithelial cells against LPS-induced injury by inhibiting cell inflammation and protecting against apoptosis through the action of exosome miRNAs. The presented results suggest that the physiological amounts of miRNAs-enriched exosomes addition to infant formula could be used as a novel preventative measure for necrotizing enterocolitis.
Background/Aims: Skeletal muscle plays an essential role in the body movement. However, injuries to the skeletal muscle are common. Lifelong maintenance of skeletal muscle function largely depends on preserving the regenerative capacity of muscle. Muscle satellite cells proliferation, differentiation, and myoblast fusion play an important role in muscle regeneration after injury. Therefore, understanding of the mechanisms associated with muscle development during muscle regeneration is essential for devising the alternative treatments for muscle injury in the future. Methods: Edu staining, qRT-PCR and western blot were used to evaluate the miR-27b effects on pig muscle satellite cells (PSCs) proliferation and differentiation in vitro. Then, we used bioinformatics analysis and dual-luciferase reporter assay to predict and confirm the miR-27b target gene. Finally, we elucidate the target gene function on muscle development in vitro and in vivo through Edu staining, qRT-PCR, western blot, H&E staining and morphological observation. Result: miR-27b inhibits PSCs proliferation and promotes PSCs differentiation. And the miR-27b target gene, MDFI, promotes PSCs proliferation and inhibits PSCs differentiation in vitro. Furthermore, interfering MDFI expression promotes mice muscle regeneration after injury. Conclusion: our results conclude that miR-27b promotes PSCs myogenesis by targeting MDFI. These results expand our understanding of muscle development mechanism in which miRNAs and genes work collaboratively in regulating skeletal muscle development. Furthermore, this finding has implications for obtaining the alternative treatments for patients with the muscle injury.
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