Differential expression of growth factors and their receptors indicates their involvement in the inverted teat defect in pigs1

Abstract

In this study 8 genes of growth factors and their receptors were investigated that are known to play a significant role in signaling pathways involved in the ontogenetic, but also tumorigenic, development of breast and mammary glands. Differential expression of fibroblast growth factor receptor 2 (FGFR2), GH receptor (GHR), hepatocyte growth factor (HGF), hepatocyte growth factor receptor (HGFR), platelet-derived growth factor alpha (PDGFA), platelet-derived growth factor receptor alpha (PDGFRA), platelet-derived growth factor beta (PDGFB), and vascular endothelial growth factor (VEGF) was analyzed in mesenchymal and epithelial teat tissue of peripubertal pigs affected and nonaffected by the inverted teat defect. Comparisons were made at the level where pigs were affected between samples derived from nonaffected animals and affected animals, including specimens of normal and inverted teats. In addition, comparisons were made at the level of the teat phenotype with normal teats of nonaffected animals vs. either the normal or the inverted teat of affected animals. All genes tested, except HGFR, showed significant differential expression at P < 0.05 in the mesenchymal or the epithelial teat tissue or both. In general, we observed more pronounced differences when comparing samples obtained from inverted tissues vs. samples from normal ones. Therefore, results of our study suggest that gene expression of the growth factors and their receptors associates directly with the teat phenotype rather than with the affection status of the investigated animals, suggesting that local processes and tissue-specific compensation by means of differential expression of growth factors and their receptors are responsible for the development of impaired teat phenotypes.

Gene expression analysis of mammary tissue during fetal bud formation and growth in two pig breeds – indications of prenatal initiation of postnatal phenotypic differences

“…We hypothesed that differential expression between the two breeds at fetal stages reflect the prenatal initiation of postnatal phenotypes also in terms of the liability to emerge inverted teats. We have previously identified molecular routes that are differentially regulated in normal compared to inverted teats at peripubertal stages [11,13]. We questioned here, whether these molecular routes are already relevant at prenatal stages and thus their modulation may initiate the postnatal development.…”

“…In fact, the examination of teat complexes of more than 2000 carcasses at the abattoir revealed mean teat numbers of around 15 and 13 in German Landrace and Pietrain, respectively [9], own observations]. The breeds also differ in the number of non-functional teats; interestingly, we observed different incidences of inverted teats of 12% in dam lines and 48% in Pietrain [10,11]. Thus differences of expression profiles of prenatal teat tissues between the two breeds could be indicative for molecular routes impertinent for the postnatal morphology and functionality of the mammary complexes.…”

“…It has been suggested that impaired prenatal development contributes to the emerging of inverted teats [10,12]. Moreover, we have previously demonstrated that genes of growth factor signaling pathways show differential expression depending on the teat phenotype and the affection status of the individual [11,13]. We aimed to elucidate whether molecular routes found to be affected due to the development of inverted teats at postnatal stages may already play a role during prenatal development.…”

Positive selection signatures in Anqing six‐end‐white pig population based on reduced‐representation genome sequencing data

“…PDGFB was suggested to be involved in the inverted teat defect in pigs (Tetzlaff et al . 2009). PLOD1 was significantly associated with back defects, like kyphosis (Lindholm‐Perry et al .…”

“…As for disease resistance genes, STAT3, CD14 and CRISPLD2 participated in the regulation of innate immunity (Sanz et al 2007;Vasarhelyi et al 2014;Islam et al 2017). PDGFB was suggested to be involved in the inverted teat defect in pigs (Tetzlaff et al 2009). PLOD1 was significantly associated with back defects, like kyphosis (Lindholm-Perry et al 2010).…”