Differential Expression of Cow Innate and Adaptive Responses Genes in Response to Eugenol

Abstract

Abstract Dietary phytochemicals have both nutritional and health benefits for farm animals. Research on the immunomodulatory effects of phytochemicals may aid in developing novel therapeutic agents and provide insights into the regulation of gene expression. Eugenol (4-allyl-2-methoxyphenyl) is the active ingredient in clove oil that has been studied for its immunomodulatory/anti-inflammatory effects. The objective of this study was to evaluate the effect of eugenol on the expression of genes associated with the cow’s innate and adaptive immune responses. Blood was collected from (n = 3) clinically healthy Holstein-Friesian cows from the North Carolina A&T State University Dairy Unit. One milliliter of whole blood from three cows was treated individually with 10 ng/mL of Eugenol (Sigma-Aldrich St. Louis, MO), or maintained in PBS, incubated at 37ºC for 30 minutes. Total RNA was extracted, reverse transcribed, and real-time PCR was carried out using the RT2 Profiler™ human Innate & Adaptive Immune Responses PCR Array containing 84 genes, as recommended by the manufacturer (Qiagen). The Livak method was used to calculate fold change (FC >2 considered significant). The analysis showed that 25 genes out of 84 genes were affected by treatment with eugenol. Among 25 genes, 19 were upregulated, and 2 genes were downregulated. The highest up-regulated and down-regulated genes following exposure to eugenol was IL23A and Interferon Regulatory Factor 7 (IRF7), respectively. The upregulation of the IL-23A gene expression by exogenous eugenol may be important in the production of pro-inflammatory cytokines and warrants further studies to investigate the mechanism involved. Interferon Regulatory Factor 7 is a critical regulator of type I interferon production and plays an important role in innate immune responses. The observed transcriptional expression of IL23A and IRF7 by eugenol provides an insight into immune modulation in cow blood.