Short communication: Production of antimicrobial peptide S100A8 in the goat mammary gland and effect of intramammary infusion of lipopolysaccharide on S100A8 concentration in milk

Abstract

This study aimed to determine the production site of antimicrobial peptide S100A8 in the goat mammary gland and changes in its concentration in milk after lipopolysaccharide (LPS) challenge. Sixteen Tokara goats were used in this study for mammary gland tissue, blood leukocyte, and milk somatic cell collection and LPS challenge. The mRNA expression and protein localization of S100A8 in the mammary gland parenchyma and teat, blood leukocytes, and milk somatic cells were examined by reverse-transcription PCR and immunohistochemistry. The S100A8 concentration in milk was measured at 0 to 144 h after intramammary challenge of LPS by enzyme immunoassay. The mRNA of S100A8 was expressed in the parenchyma and teat, leukocytes isolated from blood, and milk somatic cells. Antimicrobial peptide S100A8 was immunolocalized in the outermost layer of the teat skin of udders with and without LPS infusion, whereas in the mammary gland it was immunolocalized only in the leukocytes infiltrated in the alveoli after LPS infusion. Antimicrobial peptide S100A8 was also immunolocalized in the blood and milk leukocytes. The number of S100A8-positive cells in milk was higher than that in blood. The concentration of S100A8 in milk increased significantly at 72 h after intramammary infusion of LPS. These results suggest that S100A8 is produced in the leukocytes and that its secretion into milk is affected by LPS stimulation.

C-Type Natriuretic Peptide/Natriuretic Peptide Receptor B Regulate the Expression and Secretion of Antibacterial Peptide S100A7 in Goat Mammary Gland Through PKG/JNK/c-Jun Signaling Pathway

“…On the other hand, goat mastitis model was established in vitro using goat MECs treated by LPS. LPS, which is a cell wall component of Gramnegative bacteria, were widely used to induce mastitis model in vivo and in vitro [52,53,54,55]. Consistent with previous reports, after treatment with LPS, the in ammatory response related factors including IL-6, IL-1β and TNF-α were obviously increased.…”

Immunolocalization of Antibacterial Peptide S100A7 in Goat Mammary Gland and Lipopolysaccharide Induces the Expression and Secretion of S100A7 in Goat Mammary Gland Epithelial Cells via TLR4/NFκB Signal Pathway

“…This rapid response played an important role in the clearance of early intramammary infection. On the other hand, these results also help to explain the previous reports in which after LPS intramammary infusion, the increased concentration of S100A7 was 48 h earlier than S100A8 [21,25]. When bacteria invasion or LPS infusion in mammary alveolus, they rstly stimulated mammary epithelial cells to secrete S100A7, then leukocytes in ltrated mammary alveolus and secreted S100A8 into milk.…”

“…The teat skin is consistently exposed to external environment, and streak canal may remain open for short time after milking [23]. Considering that E. coli is one of the most important environmental pathogens [24], the constitutive expression of S100A7 and other AMP, for example S100A8 [25] in teat suggested their critical roles in innate immunity in teat which as a rst barrier to limit pathogens invasion.…”

C-Type Natriuretic Peptide Regulates the Expression and Secretion of Antibacterial Peptide S100A7 in Goat Mammary Gland Through PKG/JNK/c-Jun Signaling Pathway

“…On the other hand, goat mastitis model was established in vitro using goat MECs treated by LPS. LPS, which is a cell wall component of Gram-negative bacteria, was widely used to induce mastitis model in vivo and in vitro ( 42 – 45 ). It is reported that LPS from the commensal microbiota of the human breast induced the expression of S100A7 in breast cancer cells ( 46 ).…”