Expression Pattern of Cathelicidins in Dairy Cows During Endometritis and Role of Bovine Endometrial Epithelial Cells in Production of Cathelicidins

Abstract

Endometritis is a common bacterial disease of dairy cows. Cathelicidins are host-defense peptides that play important roles in clearance of bacteria. However, the expression pattern of these peptides during endometritis is still unclear. We hypothesize that the levels of bovine cathelicidins increased during endometritis. This study was to investigate the changes of bovine cathelicidins during endometritis. Forty-four post-partum cows (28–35 days after calving) involved in this study were grouped according to the character of vaginal discharge (VD) into three groups. These were (1) cows with clear fluid (n = 8, healthy cows group, N); (2) cows with VD containing <50% off-white mucopurulent material (n = 20, moderate endometritis cows, M); (3) cows with VD containing > 50% yellow or white purulent material (n = 16, severe endometritis cows, S). The blood, VD, and endometrial biopsies samples were collected from each cow to assess the levels of cathelicidin 1–7. Furthermore, bovine endometrial epithelial cells (BEECs) were stimulated with different concentration of Escherichia coli (2 × 106 and 2 × 107 CFU/mL) to detect the cellular source of cathelicidins. Quantitative real-time PCR (RT-qPCR) was used to detect the relative mRNA expression of cathelicidins, and enzyme-linked immune sorbent assay (ELISA) method were used to measure the protein levels. The mRNA and protein levels of cathelicidin 1–7 significantly increased during bovine endometritis (both moderate and severe endometritis), while samples from severe cases showed lower levels of cathelicidins compared to moderate cases. BEECs can express cathelicidin 1–7, and E. coli triggered the release of these proteins. High concentration of E. coli decreased the mRNA and protein levels of cathelicidins. Taken together, our results supported that cathelicidins are released as host defense molecules against the bacteria during bovine endometritis, and BEECs play an active role in expression and production of cathelicidins.

Neutrophil Extracellular Traps Mediate Bovine Endometrial Epithelial Cell Pyroptosis in Dairy Cows with Endometritis

“…In our previous study, bovine endometrial epithelial cells (BEECs) were isolated from the healthy uterus of a 6-month-old dairy cow [3]. Briefly, a healthy uterus was placed in the laboratory in sterile PBS (pH 7.2) containing 1× antibiotic-antimycotic (100×).…”

“…It affects reproductive performance through sustained inflammation and tissue damage in the endometrium, which delays the onset of ovarian cyclic activity after parturition, extends the luteal phase, and reduces the conception rate [2]. Generally, neutrophil infiltration, purulent vaginal discharge, and disruption of the endometrial epithelium are considered to constitute components in the pathophysiology of endometritis [3]. Invading microorganisms activate the innate immune system and recruit leukocytes (predominantly neutrophils) from blood vessels [4].…”

Berberine enhances autophagic flux by activating the Nrf2 signaling pathway in bovine endometrial epithelial cells to resist LPS‐induced apoptosis

“…Endometritis is one of the most universal and severe reproductive diseases and is the main cause of premature mortality in dairy cows (Li et al, 2021). Many studies have found that gram‐negative bacteria are the main pathogens that induce endometritis (Yan et al, 2021).…”

Exosomal miR-218 regulates the development of endometritis in dairy cows by targeting TGIF2/TGF-β pathway

“…Endometritis, a common disease of the reproductive system, mostly occurs in dairy cows after delivery or childbirth and causes infertility in dairy cows (Wang et al, 2021a). The causes of cow endometritis are relatively complex, and bacterial infection is one the most important etiological agents linked with this disease (Li et al, 2021a). Besides infection by pathogenic microorganisms, the autoimmune status of dairy cows determines the occurrence and development of endometrial inflammation (Siqueira et al, 2020).…”