Abstract

Galectins (Gals) are a family of animal lectins that bind β-galactosides through a carbohydrate recognition domain. Galectin-8 is a tandem-repeat galectin, secreted intracellularly and extracellularly. It is associated with neutrophil migration and has been studied as a possible therapeutic to combat inflammation. The objective of this study was to evaluate the translational and the transcriptional effects of recombinant Galectin-8 (rGal-8) on cow neutrophils. Blood was collected aseptically from Holstein-Friesian cows (n=10) from the North Carolina A&T State University Dairy Unit. Neutrophils isolated were treated with rGal-8 (2μg), or PBS (control) and were incubated at 37°C, 5% CO₂ for 1 hour. Supernatant from treated neutrophils was evaluated for total protein concentration, and galectin-8 secretion using bovine Galectin-8 Enzyme Linked-Immuno-Sorbent Assay (ELISA) kit. Total RNA was extracted, reverse transcribed, and RT-qPCR was performed using the RT² Profiler Cow Innate & Adaptive Immune Responses Array with 84 genes. The Livak method was used to calculate transcript abundance and fold change (FC>2 considered significant). Total protein concentration increased (P=0.0361) after rGal-8 treatment compared to the untreated control. Galectin-8 secretion was not significantly different in control compared to treated group (P=0.5819). Out of the 84 genes, 81 genes were differentially expressed in response to rGal-8; 14 up-regulated, 5 down-regulated, 61 genes remained unchanged. Treatment with rGal8 induced the expression of IRF7. The top five up-regulated genes include FAS, CD40, CD86, IFNGR1, STAT1; down-regulated genes were TLR9, CD14, CCR6, TICAM1, and TLR1. Selected genes were probed to validate fold change; the levels of gene expression were comparable to data from RT² array. Exposure of bovine neutrophils to rGal-8 modified expression of immune response genes. The functional significance of the change needs further studies.

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