Apoptosis and autophagy induced by TGF-B1 in bovine mammary epithelial BME-UV1 cells.
Mammary gland growth and involution is based on a dynamic equilibrium between proliferation and apoptosis of mammary gland epithelial cells (MEC). TGF-beta1 is an important antiproliferative and apoptogenic factor for mammary gland epithelial cells, acting in auto/paracrine matter and thus considered an important local regulator of mammary tissue involution. So far the studies on mammary gland involution concerned only apoptosis as a type I of MEC programmed cell death (PCD). Autophagy is known to be type II of PCD and this paper is the first, supporting evidence for the TGF-beta1-induced autophagy in bovine mammary epithelial cell line BME-UV1, as a distinct to apoptosis type of PCD. Laser scanning cytometry and confocal microscopy were used for analysis of MAP1 LC3 and Beclin 1 expression - two proteins considered being the most reliable biochemical markers of autophagy. The significant increase of MAP1 LC3 and Beclin 1 expression in cells treated with TGF-beta1 (2 ng/ml) was observed. Ultrastructural observation in electron microscopy revealed that autophagy is not only alternative, but also complementary to apoptosis type of cell death in TGF-beta1-treated bovine MEC. It was manifested by typical morphological features of apoptosis (cell shrinkage, margination and condensation of chromatin) and autophagy (autophagosomes, autophagic vacuoles) in the same cell.
Gajewska
M
M
Department of Physiological Sciences, Faculty of Veterinary Medicine, Warsaw Agricultural University, Warsaw, Poland.
Gajkowska
B
B
Motyl
T
T
D000818:Animals; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D001343:Autophagy; D002417:Cattle; D002460:Cell Line; D005260:Female; D047569:Laser Scanning Cytometry; D008321:Mammary Glands, Animal / Q000201:enzymology / Q000378:metabolism* / Q000648:ultrastructure; D018613:Microscopy, Confocal; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D013997:Time Factors; D053773:Transforming Growth Factor beta1 / Q000378:metabolism*
D051017:Apoptosis Regulatory Proteins; D008869:Microtubule-Associated Proteins; D053773:Transforming Growth Factor beta1; D011065:Poly(ADP-ribose) Polymerases