title: Innate immune responses induced by lipopolysaccharide and lipoteichoic acid in primary goat mammary epithelial cells.
abstract: BACKGROUND
  Innate immune responses induced by in vitro stimulation of primary mammary epithelial cells (MEC) using Gram-negative lipopolysaccharide (LPS) and Gram-positive lipoteichoic acid (LTA) bacterial cell wall components are well﻿- characterized in bovine species. The objective of the current study was to characterize the downstream regulation of the inflammatory response induced by Toll-like receptors in primary goat MEC (pgMEC). We performed quantitative real-time RT-PCR (qPCR) to measure mRNA levels of 9 genes involved in transcriptional regulation or antibacterial activity: Toll-like receptor 2 (TLR2), Toll-like receptor 4 (TLR4), prostaglandin-endoperoxide synthase 2 (PTGS2), interferon induced protein with tetratricopeptide repeats 3 (IFIT3), interferon regulatory factor 3 (IRF3), myeloid differentiation primary response 88 (MYD88), nuclear factor of kappa light polypeptide gene enhancer in B-cells 1 (NFKB1), Toll interacting protein (TOLLIP), and lactoferrin (LTF). Furthermore, we analyzed 7 cytokines involved in Toll-like receptor signaling pathways: C-C motif chemokine ligand 2 (CCL2), C-C motif chemokine ligand 5 (CCL5), C-X-C motif chemokine ligand 6 (CXCL6), interleukin 8 (CXCL8), interleukin 1 beta (IL1B), interleukin 6 (IL6), and tumor necrosis factor alpha (TNF).
  
  
  RESULTS
  Stimulation of pgMEC with LPS for 3 h led to an increase in expression ofCCL2,CXCL6,IL6,CXCL8,PTGS2,IFIT3,MYD88,NFKB1, andTLR4(P< 0.05). Except forIL6, andPTGS2, the same genes had greater expression than controls at 6 h post-LPS (P< 0.05). Expression ofCCL5,PTGS2,IFIT3,NFKB1,TLR4, andTOLLIPwas greater than controls after 3 h of incubation with LTA (P< 0.05). Compared to controls, stimulation with LTA for 6 h led to greater expression ofPTGS2,IFIT3,NFKB1, andTOLLIP(P< 0.05) whereas the expression ofCXCL6,CXCL8, andTLR4was lower (P< 0.05). At 3 h incubation with both toxins compared to controls a greater expression (P< 0.05) ofCCL2,CCL5,CXCL6,CXCL8,IL6,PTGS2,IFIT3,IRF3,MYD88, andNFKB1was detected. After 6 h of incubation with both toxins, the expression ofCCL2,CXCL6,IFIT3,MYD88,NFKB1, andTLR4was higher than the controls (P< 0.05).
  
  
  CONCLUSIONS
  Data indicate that in the goat MEC, LTA induces a weaker inflammatory response than LPS. This may be related to the observation that gram-positive bacteria cause chronic mastitis more often than gram-negative infections.
authors.affiliation: Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA.|Department of Molecular and Translational Medicine, University of Brescia, Brescia, 25123 Italy.
authors.forename: Omar
authors.initials: O
authors.lastname: Bulgari
authors.affiliation: Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA.|Institute of Animal Nutrition, Sichuan Agricultural University, Chengdu, 611130 China.
authors.forename: Xianwen
authors.initials: X
authors.lastname: Dong
authors.affiliation: Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA.
authors.forename: Alfred L
authors.initials: AL
authors.lastname: Roca
authors.affiliation: Department of Molecular and Translational Medicine, University of Brescia, Brescia, 25123 Italy.
authors.forename: Anna M
authors.initials: AM
authors.lastname: Caroli
authors.affiliation: Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA.|Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA.
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Loor
keywords: Gene expression; Inflammation; Lactation; Mastitis