Effect of the SLICK1 genotype on HAMP and HSPB8 expression in Holstein cow tissues

Abstract

The SLICK1 mutation in bovine confers a short, sleek hair coat and has been associated with improved thermotolerance, shorter calving intervals, and better immune function. However, molecular mechanisms underlying these or other physiological advantages remain uknown. The present study aimed to evaluate whether the expression of two genes, hepcidin antimicrobial peptide (HAMP) and heat shock protein family B member 8 (HSPB8), differs in the liver and uterus of Holstein cows with or without the SLICK1 mutation. Liver and uterus samples were obtained at a local slaughterhouse from five wild-type and three heterozygous SLICK1 Holstein cows of the Agricultural Experiment Station of the University of Puerto Rico. Total RNA was extracted with a kit based on magnetic-beads, cDNA was synthesized and qPCR was performed with gene-specific primers, and relative expression calculated using the delta-delta Ct method with RPL19 as the housekeeping gene. The relative expression of HAMP was lesser (P<0.02) in the liver of SLICK1 (0.2 ± 0.1) when compared to wild-type cows (1.2 ± 0.7). Similarly, the relative expression of HSP8 was lesser (P<0.03) in the uterus of SLICK1 (0.6 ± 0.2) when compared to wild-type cows (1.0 ± 0.3). No other significant differences in the relative expression of HAMP or HSPB8 were observed. Given the role of HAMP in iron regulation and immune response, and HSPB8 in cellular protection under heat stress, these results suggest potential molecular pathways influenced by the SLICK1 mutation. Ongoing analyses aim to assess gene expression in additional tissues to further elucidate the physiological implications of the SLICK1 genotype in Holstein cattle.