Increased mRNA expression of selected antimicrobial peptides around ovulation and during inflammatory processes in the bovine endometrium postpartum

• Published in: Theriogenology 2016-11, Vol.86 (8), p.2040-2053
• Main Authors: Ibrahim, M., Peter, S., Gärtner, M.A., Michel, G., Jung, M., Einspanier, R., Gabler, C.
• Format: Article
• Language: English
• Subjects: Animals; Antimicrobial Cationic Peptides - genetics; Antimicrobial Cationic Peptides - metabolism; Antimicrobial peptides; Bacillus pumilus; Bacillus pumilus - physiology; Cattle - physiology; Cells, Cultured; Cow; Endometrial epithelial cells; Endometritis; Endometrium - cytology; Endometrium - metabolism; Epithelial Cells - physiology; Estrous cycle; Estrous Cycle - physiology; Female; Gene Expression Regulation - physiology; Postpartum Period - metabolism; Pregnancy; RNA, Messenger - genetics; RNA, Messenger - metabolism; S100 Proteins - genetics; S100 Proteins - metabolism
• ISSN: 0093-691X; 1879-3231
• DOI: 10.1016/j.theriogenology.2016.06.022

In the uterus, the first pathogen confrontations take place at the luminal endometrial epithelium. Therefore, it is required that these cells have the potential to recognize and respond to a bacterial infection. Antimicrobial peptides (AMP), part of the innate immune system in addition to cytokines, are principal effector molecules of mucosal immunity against pathogens. One important family of AMP that can permeabilize bacterial membranes is the beta-defensin (DEFB) family, which includes the following members: DEFB1, DEFB4A, and DEFB5, lingual AMP, and tracheal AMP. The bactericidal/permeability-increasing protein is also a cationic AMP that results in the death of bacteria. Another AMP family is the S100 calcium-binding protein (S100A) family including the following members: S100A8, S100A9, S100A11, and S100A12. These AMP exert their antimicrobial action through chelation of several ions. The aim of the present study was to evaluate mRNA expression patterns of selected AMP in bovine endometrial cells collected (1) at different stages of the estrous cycle (postovulatory, early-to-mid luteal, late luteal, and pre-ovulatory phase); (2) during the puerperium depending on uterine health status (healthy, subclinical, or clinical endometritis) starting on Day 24 to 30 postpartum for 3 weeks on a weekly basis; and (3) in vitro after co-culturing with Bacillus pumilus at three different multiplicities of infection (MOI 1, 5, and 10) up to 6 hours. The results reported that the mRNA expression of all candidate AMP, except DEFB1, S100A8, and S100A9, was estrous cycle dependent. In particular, around the time of ovulation, the transcription level of most AMP was higher (P