NOTCH PATHWAY MODULATES VEGF AND ENDOCAN MEDIATED ANGIOGENESIS IN THE BOVINE MAMMARY GLAND DURING PUBERTAL DEVELOPMENT

NADIA BONADEO; AGUSTINA CHIMENTO; SOFÍA PERRONE; DAMASIA BECU-VILLALOBOS; CAROLINA CRISTINA; ISABEL MARÍA LACAU-MENGIDO

Jornada; Jornadas de la Sociedad Argentina de Biología (SAB); 2018

We have previously described a differential expression and activation of Notch receptors during bovine mammary glanddevelopment. In this work, we aimed to study the relation between Notch pathway components, proliferation and angiogenesisduring pubertal development. In Holstein heifers of 20, 30, 40 and 70 weeks of age, we studied SMA and PCNA expression byimmunohistochemistry and we observed an increased microvascular density at 30 weeks of age (p<0.1). By Western blot studies, wealso found an increase in the endothelial cells marker CD34 at 30 weeks of age and a decrease at 40 weeks of age (p=9.8x10 -10 ).Furthermore we measure Hes1, Hey1 and Hey2 mRNA, target genes of Notch pathway, and we found an increase of Hey1 geneexpression at 40 weeks of age (p=1x10 -6 ) and an increase of Hey2 at 70 weeks of age (p=0.0002). Moreover Real time PCR studiesshowed that the expression of the Jagged1 ligand also increased at 30 weeks of age (p=0.007) and Delta1 ligand at 70 weeks of age(p=0.044). We also determined the mRNA levels of the angiogenic markers VEGF and Endocan. We observed an increase inEndocan at 40 weeks of age (p=0.016) and an increase of VEGF at 70 weeks of age (p=0.0078). We found a positive correlationbetween the expression of Notch1 receptor and Hey1 (p=0.0017; r=0.67) and Hey2 (p=0.0041; r=0.67), and between Notch3 receptorand Hey1 (p=0.017; r=0.56). Likewise, both target genes correlate positively with VEGF (p=0.0001; r=0.75) (p=0.024; r=0.53) andEndocan (p=0.0024; r=0.59) (p=0.016; r=0.53). In conclusion, we observed Notch pathway activation at all studied ages, withsignificant increments at the time of puberty onset (30 and 40 weeks of age). We also observed more angiogenesis at this peripubertalstage. Our results support the Notch pathway activation during bovine mammary gland development through Hey1 and Hey2 targetgenes and would indicate a role of Notch pathway in the developmental angiogenesis mediated by VEGF and Endocan.