MicroRNA Regulation of Bovine Monocyte Inflammatory and Metabolic Networks in anIn VivoInfection Model

Abstract

Bovine mastitis is an inflammation-driven disease of the bovine mammary gland that costs the global dairy industry several billion dollars per year. Because disease susceptibility is a multifactorial complex phenotype, an integrative biology approach is required to dissect the molecular networks involved. Here, we report such an approach using next-generation sequencing combined with advanced network and pathway biology methods to simultaneously profile mRNA and miRNA expression at multiple time points (0, 12, 24, 36 and 48 hr) in milk and blood FACS-isolated CD14+ monocytes from animals infected in vivo with Streptococcus uberis. More than 3700 differentially expressed (DE) genes were identified in milk-isolated monocytes (MIMs), a key immune cell recruited to the site of infection during mastitis. Upregulated genes were significantly enriched for inflammatory pathways, whereas downregulated genes were enriched for nonglycolytic metabolic pathways. Monocyte transcriptional changes in the blood, however, were more subtle but highlighted the impact of this infection systemically. Genes upregulated in blood-isolated monocytes (BIMs) showed a significant association with interferon and chemokine signaling. Furthermore, 26 miRNAs were DE in MIMs and three were DE in BIMs. Pathway analysis revealed that predicted targets of downregulated miRNAs were highly enriched for roles in innate immunity (FDR < 3.4E−8), particularly TLR signaling, whereas upregulated miRNAs preferentially targeted genes involved in metabolism. We conclude that during S. uberis infection miRNAs are key amplifiers of monocyte inflammatory response networks and repressors of several metabolic pathways.

Solexa sequencing and custom microRNA chip reveal repertoire of microRNAs in mammary gland of bovine suffering from natural infectious mastitis

“…More identifications of the bovine miRNA expression atlas in different tissues and cells are necessary to further fill in the gap (Lawless et al . ,). These newly identified miRNAs could significantly expand the bovine miRNA spectrum and refine their annotations.…”

“…Using next‐generation sequencing and RT‐PCR approaches, several studies have identified differentially expressed bovine miRNAs, target genes, KEGG pathways and related regulatory networks and pointed out their roles in regulating host response to S. aureus or Escherichia coli , in vivo and in vitro , at early stages of infection (Lawless et al . , ,; den Breems et al . ; Jin et al .…”

MicroRNA-26b Modulates the NF-κB Pathway in Alveolar Macrophages by Regulating PTEN

“…Since BRD is a multi-factorial complex phenotype, dissecting molecular networks involved is essential for understanding the pathogenesis of BRD. It has been demonstrated that miRNAs play important roles in bovine monocyte inflammatory and metabolic networks (56). Many LPS-responsive miRNAs also have a role in proinflammatory cytokine production in other species rather than bovine (57-59).…”

Non-Coding RNA Roles in Ruminant Mammary Gland Development and Lactation

“…MiRNAs have been shown to play roles in bovine infection and immunity in a wide range of tissues [54,[106][107][108][109][110][111][112][113]. For mammary gland, Naeem et al [114] studied the expression of 14 miRNAs (miR-10a, miR-15b, miR-16a, miR-17, miR-21, miR-31, miR-145, miR-146a, miR146b, miR-155, miR-181a, miR-205, miR-221 and miR-223) in MG tissue challenged with Streptococcus uberis and identified three downregulated miRNAs (miR-181a, miR-16 and miR-31) and one upregulated miRNA (miR-223) in infected versus healthy tissue.…”