Gene expression profiling of bovine bronchial epithelial cells exposed in vitro to bovine herpesvirus 1 and Mannheimia haemolytica

Abstract

Bovine respiratory disease (BRD) often occurs when active respiratory virus infections (BHV-1, etc.) impair resistance to Mannheimia haemolytica infection in the lower respiratory tract. The interactions that occur when the respiratory epithelium encounters these viral and bacterial pathogens are poorly understood. We used Agilent bovine gene microarray chips containing 44,000 transcripts to elucidate bovine bronchial epithelial cell (BBEC) responses following in vitro exposure to BHV-1 alone, M. haemolytica alone, or both BHV-1 and M. haemolytica. Microarray analysis revealed differential regulation (>2-fold) of 978 transcripts by BHV-1 alone, 2040 transcripts by M. haemolytica alone, and 2189 genes by BHV-1 and M. haemolytica in combination. M. haemolytica treatment produced significantly greater inductions (>10-fold) of several inflammation associated genes, such as CXCL2, IL-6, IL-1α, e-selectin, and IL-8, than to BHV-1 alone. Functional analysis of the microarray data revealed a significant upregulation of genes involved in important biological processes such as inflammation (TNF-α, IL-8, Tlr-2, IL-1, CXCL2, CSF2), vascular functions (VEGF, EDN2) and leukocyte migration (ICAM1, IL-16) during a co-infection with BHV-1 and M. haemolytica compared to either pathogen alone. This study provides evidence to support that lung epithelial cells are a source of mediators that may promote inflammatory changes observed during bovine respiratory disease.

Pathogenic Mannheimia haemolytica Invades Differentiated Bovine Airway Epithelial Cells

“…In addition to their barrier function, AECs also play an important role in orchestrating the host innate immune response to infection through the release of proinflammatory cytokines and chemokines (33, 77, 98, 99). The proinflammatory cytokines IL-1β, IL-6, and TNFα as well as the proinflammatory chemokine CXCL8 are produced by bovine AECs during BRD (23, 34, 35, 100). In the present study, challenge of differentiated BBECs stimulated the release of IL-1β, IL-6, TNFα, and CXCL8 by strains of both M.…”

“…The respiratory epithelium provides a physicochemical barrier against inhaled microorganisms and particulates which involves the presence of intercellular junctions and mucociliary clearance (32, 33). Furthermore, AECs are involved in the innate immune response and, during BRD, are the source of the proinflammatory mediators which stimulate the activation and regulation of neutrophils and macrophages (22, 34, 35). Submerged AEC cultures, including either primary cells or immortalized cell lines, have been used to investigate interactions of M.…”

“…Submerged AEC cultures, including either primary cells or immortalized cell lines, have been used to investigate interactions of M. haemolytica (34, 36–38) with the bovine respiratory tract, but these have various limitations: the cultures do not reflect the multicellular complexity of the parental tissue in vivo and lack its three-dimensional (3-D) architecture, and the physiological conditions are not representative of those found within the bovine URT. However, those characteristics that are lacking in submerged cultures can be recapitulated using differentiated AECs grown at an air-liquid interface (ALI) and such cell culture approaches have been used to study the interactions of various bacterial and viral pathogens with different host species (39–57).…”

Prevalence of Pneumonia in Sheep and Goats Slaughtered at Elfora Bishoftu Export Abattoir, Ethiopia: A Pathological Investigation

“…This suggests that the disease was most likely attributed to exposure of the animals to various stresses during transportation for slaughter. Stress factors like long transportation under poor condition, overcrowding, sudden climate change at transit, unrest in the lairage, inadequate feed and water provision, and other underling diseases including predisposing viral infection of the respiratory system such as parainfluenza-3, adenoviruses, and respiratory syncytial virus are widely accepted as predisposing factors for bacterial pneumonia [4, 42].…”

Bovine respiratory syncytial virus infection enhances Pasteurella multocida adherence on respiratory epithelial cells

“…We and others have used experimental adherence assays based on respiratory and/or bovine epithelial cell lines (Galdiero et al, 2002;N'jai et al, 2013). Galdiero et al (2002) point out that an in vitro model is essential to clarify the relationship between virus and bacterium.…”