Mammary Localization and Abundance of Laminin, Fibronectin, and Collagen IV Proteins in Prepubertal Heifers

Abstract

The objective was to determine localization and abundance of extracellular matrix proteins fibronectin, laminin, and collagen in mammary tissues from ovariectomized or intact prepubertal heifers. Mammary parenchyma and fat pad tissues were collected from 14 6-mo-old heifers: eight were ovariectomized between 1 to 3 mo of age, and six were used as intact controls. Distribution of total collagen was assessed by Sirius Red staining of tissue sections. Fibronectin, laminin, and type IV collagen were assessed by immunohistochemistry. Abundance of fibronectin and laminin was also analyzed by western blotting. Total mammary mass was much less in ovariectomized animals (130 +/- 21 vs. 304 +/- 25 g). Histological structure differed as parenchyma from intact animals contained abundant, complex branching epithelial terminal ductular units, whereas terminal ductular units from ovariectomized animals were mostly major ductal structures with little or no branching. Collagen fibers were abundant and densely packed throughout interlobular stroma and were less abundant and more diffuse within intralobular stroma. Type IV collagen was primarily in basal lamina of mature ducts, whereas fibronectin and laminin staining were present throughout parenchymal stroma, in both intact and ovariectomized animals. Using western blotting, fibronectin was more abundant within parenchyma than in the fat pad and significantly higher in parenchyma from ovariectomized heifers. Laminin was more abundant in parenchyma from intact than ovariectomized animals (30 vs. 17 densitometric units/mg of tissue), but laminin was similar between parenchyma and fat pad. These results provide initial evidence that fibronectin, laminin, and collagen participate in regulation of heifer prepubertal mammary development.

Fibronectin on circulating extracellular vesicles as a liquid biopsy to detect breast cancer

“…This protein has been found to be expressed in BC [40, 41], and other cancers [37, 42, 43]. Moreover, it has been reported that FN could induce progression of various cancer cells [36, 37] and is strongly expressed in breast carcinoma, and its distribution is different from that of normal breast parenchyma [38, 39]. Although measurement of FN levels in other cancer groups is necessary, we have limitation in this study to collect patients' plasma with other cancers in hospital.…”

Regulation of Mammary Development as It Relates to Changes in Milk Production Efficiency

“…Based on their observations, these authors suggested a role for the integrins in coordinating the cytoskeleton and regulating the induction of cellular differentiation by PRL. To regulate cellular proliferation and mammary growth, ECM influences the cellular response to steroid hormones (Wilde et al, 1984), and also appears to interact with local growth factor signaling pathways (Berry et al, 2003). In addition, remodeling of ECM and mammary involution is induced by decreased milking frequency and milk stasis in ruminants (Weng et al, 2008).…”

Endoscopic Examination and Tissue Sampling of the Bovine Teat and Udder Cistern

“…In contrast to the prelevation of mammary tissue biopsies through invasive surgery (Knight et al, 1992;Farr et al, 1996) or at necropsy (Cifrian et al, 1994;Berry et al, 2003;Pfaffl et al, 2003), the endoscopic procedure yields much smaller amount of mammary tissue. The limited sample size did not, however, compromise the possible applications of the technique.…”