Background The antibacterial and immunomodulatory activities of bacteriocins make them attractive targets for development as anti-infective drugs. Although the importance of the enteric nervous system (ENS) in the struggle against infections of the intestine has been demonstrated, whether it is involved in bacteriocins anti-infective mechanisms is poorly defined. Results Here, we demonstrated that the bacteriocin Microcin J25 (J25) significantly alleviated diarrhea and intestinal inflammation in piglets caused by enterotoxigenic Escherichia coli (ETEC) infection. Mechanistically, macrophage levels were significantly downregulated after J25 treatment, and this was replicated in a mouse model. Omics analysis and validation screening revealed that J25 treatment induced significant changes in the dopaminergic neuron pathway, but little change in microbial structure. The alleviation of inflammation may occur by down-regulating dopamine receptor (DR) D1 and the downstream DAG-PKC pathway, thus inhibiting arachidonic acid decomposition, and the inhibition of macrophages may occur through the up-regulation of DRD5 and the downstream cAMP-PKA pathway, thus inhibiting NF-κB. Conclusions Our studies’ findings provide insight into the changes and possible roles of the ENS in J25 treatment of ETEC infection, providing a more sophisticated foundational understanding for developing the application potential of J25.
Hai Zhang,Shengsheng Zhang,Li Wang,Xiaofei Liu,Yuntang Wu
Previous results from our laboratory showed that chitosan biguanidine hydrochloride (CSGH) and chitooligosaccharide guanidine (COSG) could control glucose uptake by regulating the expression of glucose transporters (GLUTs) in vitro experiments. In this study, we try to delineate changes observed in activation of diacylglycerol (DAG)/protein kinase C- β (PKC- β ) pathway and GLUT2 in kidney. STZ-induced diabetic rats were administered COSG via daily intra-gastric gavage for 8 weeks. Obviously, COSG significantly attenuated fasting blood glucose and blood glucose level by modulating the over-expression of GLUT2 and the level of DAG as well. Immunohistological examination revealed that factors such as PKC- β and transforming growth factor- β (TGF- β ) diminished to various extents after treatment with COSG, which impinged on the synthesis of extracellular matrix (ECM) components like fibronectin (FN). As a result, high glucose-induced activation of DAG/PKC pathway is inhibited, which is associated with the concentration of glucose controlled by the expression of GLUT2 with the treatment of COSG.
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