Transcriptome analysis of mammary tissues reveals complex patterns of transporter gene expression during pregnancy and lactation

Abstract

As a complex Ca2+-rich fluid mixture of water, casein, lactose and several ions, milk secretion requires a number of unknown transporters, which can be identified by a genome-wide microarray study in mammary tissues of lactating animals. Ca2+ was reported to be secreted across mammary epithelial cells through the transcellular pathway, presumably involving TRPC (canonical transient receptor potential) channels. In the present study, we have used quantitative real-time PCR to demonstrate that the human mammary cell line MCF-7, as well as rat mammary tissues from pregnant and lactating rats, expressed TRPC1, TRPC5 and TRPC6. Expression of TRPC1, TRPC5 and TRPC7 were markedly up-regulated, whereas that of TRPC3 and TRPC4 was down-regulated in the early lactating period. To further identify other transporter genes affected by lactation, a highly sensitive Illumina microarray featuring Bead Array technology was performed on RNA samples from mammary tissues of lactating rats. We found that, of the 384 transcripts changed during lactation, 31 transcripts were involved in the transport of water and electrolytes, such as Ca2+, Na+, K+, Cl-, I-, Fe2+, sulfate and phosphate. The present study, therefore, provides information for further investigation of the mechanism of lactation-induced transport adaptation in mammary epithelial cells.

Properties and Therapeutic Potential of Transient Receptor Potential Channels with Putative Roles in Adversity: Focus on TRPC5, TRPM2 and TRPA1

“…It is also present in many other tissues of the body, but again it is not uniformly expressed. Non-neuronal examples of its expression include sperm head [11], vascular smooth muscle cells [12-14], endothelial cells [15-18], adrenal medulla [19], mammary glands [20], yolk sac [17], activated T cells [21], monocytes in hypertension [22], and cardiac ventricles in hypertension [23]. …”

SPCA2 Regulates Orai1 Trafficking and Store Independent Ca2+ Entry in a Model of Lactation

“…Multiple Ca 2+ transporters, regulators and binding proteins must be upregulated to drive transcytosis of calcium while maintaining submicromolar cytoplasmic Ca 2+ concentrations to avoid Ca 2+ mediated toxicity and cell death. Transport and sequestration of Ca 2+ is achieved by coordinated increase in the expression of Ca 2+ pumps, and channels [10]. Current models suggest that polarized mammary secretory cells take up Ca 2+ at the basolateral membrane via yet to be described Ca 2+ channel(s) [9].…”

Biosynthesis of milk fat, protein, and lactose: roles of transcriptional and posttranscriptional regulation

“…The use of large transcriptomic analysis (i.e., microarray or RNA sequencing) by which to study the adaptation of mammary gland to lactation and/or change in milk production under specific conditions has been carried out in mouse (4,54,122,123,143,189,191,217,236,256), rat (3,47,187), bovine (31,36,56,75,96,144,183,209,218,233,239), sheep (209), goat (71,163,164), human (121,139,147), pig (204), kangaroo (120), and seal (144). It is beyond the scope of the current review to present a thorough discussion of the results from those studies.…”