Basolateral pressure challenges mammary epithelial cell monolayer integrity, in vitro

Total flavonoids of Abrus cantoniensis inhibit CD14/TLR4/NF-κB/MAPK pathway expression and improve gut microbiota disorders to reduce lipopolysaccharide-induced mastitis in mice

Established a model of lipopolysaccharide (LPS)-induced mastitis in mice, pathological sections and myeloperoxidase were used to detect the degree of tissue damage, enzyme-linked immunosorbent assay (ELISA) was performed to detect the expression of pro-inflammatory cytokines, meanwhile fluorescence quantitative PCR experiments were performed to detect the mRNA expression of CD14/TLR4/NF-κB/MAPK signalling pathway, and the faeces of mice were collected for 16S measurement of flora. The results showed that Abrus cantoniensis total flavonoids (ATF) could significantly reduce the damage of LPS on mammary tissue in mice and inhibit the secretion of inflammatory factors such as TNF-α, IL-1β and IL-6. At the mRNA level, ATF inhibited the expression of CD14/TLR4/NF-κB/MAPK pathway and enhanced the expression of tight junction proteins in the blood-milk barrier. In the results of the intestinal flora assay, ATF were found to be able to regulate the relative abundance of the dominant flora from the phylum level to the genus level, restoring LPS-induced gut microbial dysbiosis. In summary, ATF attenuated the inflammatory response of LPS on mouse mammary gland by inhibiting the expression of CD14/TLR4/NF-κB/MAPK pathway, enhancing the expression of tight junction proteins and restoring LPS-induced gut microbial dysbiosis. This suggests that ATF could be a potential herbal remedy for mastitis.

Regulation of Epithelial Cell Functions by the Osmolality and Hydrostatic Pressure Gradients: A Possible Role of the Tight Junction as a Sensor

Epithelia act as a barrier to the external environment. The extracellular environment constantly changes, and the epithelia are required to regulate their function in accordance with the changes in the environment. It has been reported that a difference of the environment between the apical and basal sides of epithelia such as osmolality and hydrostatic pressure affects various epithelial functions including transepithelial transport, cytoskeleton, and cell proliferation. In this paper, we review the regulation of epithelial functions by the gradients of osmolality and hydrostatic pressure. We also examine the significance of this regulation in pathological conditions especially focusing on the role of the hydrostatic pressure gradient in the pathogenesis of carcinomas. Furthermore, we discuss the mechanism by which epithelia sense the osmotic and hydrostatic pressure gradients and the possible role of the tight junction as a sensor of the extracellular environment to regulate epithelial functions.