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

Abstract

During infection, the infected tissue secretes a variety of endogenous peptides to resist further invasion of pathogens. Among these endogenous peptides, the natriuretic peptides and the antimicrobial peptides attracted the most attention. C-type natriuretic peptide (CNP) and its receptor natriuretic peptide receptor B (NPR-B) were members of the natriuretic peptide system. The antimicrobial peptide S100A7 plays an important role to resist infection of bacteria in mastitis. It is reported that the expression of S100A7 is regulated by an activator protein-1 (AP-1)-responsive promoter. As a subunit of AP-1, c-Jun is a downstream target of CNP/NPR-B signaling pathway. Therefore, it is a hypothesis that the CNP/NPR-B signaling pathway induces the expression and secretion of S100A7 in mammary glands to take part in local mammary gland innate immunity. To verify this hypothesis, goat mammary gland and isolated mammary epithelial cells (MECs) were used to explore the expression of CNP/NPR-B and their physiological roles in goat mammary gland. The results showed that goat mammary gland expressed NPR-B, but not CNP. The expression and secretion of S100A7 in goat MECs were obviously induced by CNP/NPR-B signaling pathway. After treatment with CNP, the cyclic guanosine monophosphate (cGMP) level in goat MECs was significantly upregulated. Along with the upregulation of cGMP level, the phosphorylation levels of c-Jun N-terminal kinase (JNK) and its target c-Jun were also increased gradually. KT5823 is a specific inhibitor for protein kinase G (PKG). KT5823 remarkably inhibited the phosphorylation of JNK and c-Jun induced by CNP. Correspondingly, KT5823 evidently inhibited the expression and secretion of S100A7 induced by CNP. On the other hand, the expression of NPR-B and S100A7 was upregulated in the mastitis goat mammary gland. But, there was no significant difference in expression of CNP between healthy and mastitis goat mammary gland tissues. The goat mastitis model was established in vitro using goat MECs treated by lipopolysaccharide (LPS). LPS treatment also could increase the expression of NPR-B and S100A7. In conclusion, goat mammary gland expressed NPR-B, indicating mammary gland was the target organ for natriuretic peptide system. Moreover, CNP, through NPR-B/JNK/c-Jun signaling pathway to regulate the expression and secretion of S100A7 in MECs, played an important role in mammary gland innate immunity.

Estradiol Regulates the Expression and Secretion of Antimicrobial Peptide S100A7 via the ERK1/2-Signaling Pathway in Goat Mammary Epithelial Cells

“…Considering estradiol is the most important and most biologically active hormone in estrogen [ 10 ], gMECs were treated with estradiol to explore the relationship between S100A7 and estradiol. According to recent research, LPS (5 μg/mL) can induce the synthesis and secretion of S100A7 in gMECs for 6 h. LPS also induced the expression and secretion of S100A7 in the present study, which supports the previous research [ 24 , 28 ], so we used it as a positive group at this point in the whole experiment. gMECs were further treated with different estradiol concentrations for 6 h. Interestingly, the expression of S100A7 was significantly induced with estradiol treatment as well as S100A7 secretion, which supports the research that S100A7 was induced with estradiol treatment in bovine mammary epithelial cells [ 12 ].…”

“…In order to determine whether E2 can induce the expression of S100A7 in gMECs cultured in vitro, the isolated gMECs were treated with 1 nM, 10 nM, 100 nM E2 and/or LPS (5 μg/mL), respectively, for 6 h; LPS is a positive group which has been proved to induce S100A7 mRNA expression and secretion in gMECs [ 24 , 28 ]. Firstly, the concentrations of LPS and E2 had no significant effect on the cell viability of gMECs for 24 h ( Figure 4 A, p > 0.05), the original data of Cell viability(OD) is shown in Table S1 , which showed that they can be used for subsequent research.…”

“…Moreover, MAPKs include three major subfamilies, the c-jun N-terminal kinases (JNKs), the p38 MAPKs and the extracellularly responsive kinases (ERKs) [ 41 , 42 ]. The expression and secretion of S100A7 was induced in gMECs especially with C-type natriuretic peptide treatment via the JNKs signaling pathway [ 28 ]. While the question of whether estradiol participates in the synthesis and secretion of S100A7 through these signaling pathways in gMECs still remains unclear, these pathways were detected with estradiol treatment, and results show that the ERK signal pathway was activated while other pathways had little significance.…”

S-100 Proteins: Basics and Applications as Biomarkers in Animals with Special Focus on Calgranulins (S100A8, A9, and A12)

“…Osteosarcoma [29] Pancreatic cancer [30] Alzheimer's disease [31] Potential therapeutic target for acute myocardial infarction [32] Neurodegenerative diseases [33] Veterinary studies: Porcine reproductive and respiratory syndrome virus [34] Atopic dogs [35] Toxoplasma gondii infection [36] S100A7 (Psoriasin1) Psoriasis and inflammatory skin diseases [37] Squamous cell carcinomas and large cell lung carcinomas [38] Alzheimer disease [39] Wound healing process [40] Role in breast cancer [41] Veterinary studies: Mastitis in goat [42] Use of fecal calprotectin [43] Biological function and use as biomarker [44] Diagnosis of sepsis [45] S100A10 (Calpactin-1 Plasminogen receptor S100A10)…”