Proteomic analysis of differentially expressed proteins in caprine milk during experimentally induced endotoxin mastitis

Abstract

The goal of the current study was to identify proteins in goat milk before and at 18 h following intramammary challenge with lipopolysaccharide (LPS). Initial evaluation of protein profiles generated using 2-dimensional gel electrophoresis on skim milk samples from a group of 6 goats collected before challenge and at 18, 24, and 48 h after LPS challenge revealed little change in the abundance of casein proteins, and minimal changes in the presence or abundance of the plasma protein serum albumin, which is known to leak into milk during coliform mastitis in dairy cattle. Proteins in baseline milk samples and in milk from the same goats 18 h post-LPS challenge were excised from the gels, and peptides were sequenced using nano-flow liquid chromatography coupled with tandem mass spectrometry. Despite the overwhelming presence of casein proteins and β-lactoglobulin, the lower abundance proteins β-2-microglobulin, fatty acid-binding protein, serum albumin, and retinol-binding protein were detected in skim milk samples from healthy goats. Skim milk samples 18 h postchallenge were characterized by the sustained presence and abundance of the casein proteins, and by the presence of haptoglobin, serum amyloid A, lactoferrin, cathelicidin-1, and cathelicidin-3. No marked differences in the intensity of the spot corresponding to serum albumin were observed in gels of skim milk samples 18 h postchallenge, which could indicate that the breakdown of the blood-milk barrier during endotoxin mastitis may not be as profound in goats as has been observed in dairy cattle. Nonetheless, the occurrence of an inflammatory response was supported by elevated somatic cell counts in the goat milk following inoculation with endotoxin, as well as by the presence of both antimicrobial and acute phase proteins. The results provide information about the composition of proteins in goat milk as well as added knowledge of the host response during endotoxin mastitis in goats.

Control mechanisms for producing antimicrobial factors in ruminant mammary gland

“…Cathelicidin‐1 and 3 have also been identified in goat skim milk (Olumee‐Shabon et al . ). In cows, using proteomic analysis, cathelicidin‐1, 2, 3 and 4 have been identified in the skim milk and whey of mastitic cows (Boehmer et al .…”

Elucidating Novel Bacterial Targets and Designing Unusual Antimicrobial Peptides: Two Faces of the Same Proteomic Coin

“…Early 2-DE-based proteomics evaluation revealed few modifications in the expression of casein and plasma protein serum albumin, which are known to leak into milk during coliform mastitis in dairy cattle. Moreover, peptides were sequenced using nano-flow liquid chromatography coupled with tandem MS and, despite the notable presence of casein proteins and β-lactoglobulin, AMPs from the cathelicidn family was also observed [70]. These data suggest that milk proteins contain AMPs, providing a selective advantage through evolution by protecting the mother's mammary gland and her nursing offspring from infection.…”

“…Since a wide number of observed peptides showed significant sequence overlap with AMPs, antibacterial assays were performed, showing that milk peptide mixtures were able to inhibit bacterial development. Furthermore, goats' milk was also evaluated in order to better understand the proteins synthesized in response to intramammary challenge with bacterial LPS, which elicited strong animal immune responses [70]. Early 2-DE-based proteomics evaluation revealed few modifications in the expression of casein and plasma protein serum albumin, which are known to leak into milk during coliform mastitis in dairy cattle.…”

Effect of steroid hormones on the innate immune response induced by Staphylococcus aureus in the goat mammary gland

“…From days −2 to 3, oestradiol benzoate (1 mg/0.5 ml, ASKA Pharmaceutical Co., Ltd.) was injected intramuscularly once a day. Heat-killed SA (InvivoGen, CA, USA) at a concentration of 2 × 10 8 cells per 5 ml saline was administered by intramammary infusion to the left udder at day 0, whilst only saline was infused to the right udder as a control, as described in previous studies (Huang et al, 2012;Isobe, Hosoda et al, 2009;Olumee-Shabon, Swain, Smith, Tall, & Boehmer, 2013).…”