Transporter gene expression in rat lactating mammary epithelial cells & primary organoid cultures using quantitative real-time reverse transcription polymerase chain reaction (QRT-PCR)
Bibliographic record
Abstract
Transporters dynamically expressed at the mammary gland transport critical nutrients into the breast milk of nursing mothers to meet the nutritional demands of the suckling infant.However, xenobiotics may interact with these transporters to potentially alter the nutrient composition of milk and compromise neonatal nutrition.The aim of the present study was to quantitatively evaluate the constitutive expression of various nutrient transporters in whole mammary gland tissue and mammary epithelial organoids (MEO) isolated from female Sprague-Dawley rats at various stages of pregnancy, lactation, and involution.Furthermore, the study's aim was to determine if appropriately cultured mammary epithelial organoids (MEO) maintain in vivo transporter expression to lay down critical groundwork for the development of an in vitro screening tool assessing xenobiotic-nutrient transporter interactions.The following transporters were evaluated using quantitative real-time reverse transcription polymerase chain reaction (QRT-PCR): multidrug resistance protein (Mdr) 1a, 1b; multidrug resistance-like protein (Mrp) 1; organic cation transporter (Oct) 1; organic cation/carnitine transporter (Octn) 1, 2, and 3; concentrative nucleoside transporter (Cnt) 1, 2, and 3; equilibrative nucleoside transporter (Ent) 1, 2, and 3; nucleobase transporter (Ncbt) 1 and 2; oligopeptide transporter (Pept) 1 and 2; methotrexate carrier (Mtx) 1; divalent metal transporter (Dmt) 1; and the milk protein β-casein.Transporter expression patterns in MEO differed from whole tissue for β-actin, Mdr1a, Mdr1b, Oct1, Octn3, Ent3, Cnt1, Cnt3, Ncbt1, Pept2, Mtx1, and β-casein.This brings into question whether whole mammary gland tissue is truly appropriate for an understanding of transporter expression in the mammary epithelium.Nevertheless, four general transporter expression patterns emerged in isolated MEO: decline throughout lactation (Mdr1a, Mdr1b, Mrp1 & Dmt1), increase throughout lactation (Cnt1 & Octn3), increase in early lactation (Oct1, Octn2, Ent1, Cnt2, Cnt3, Pept2 & Mtx1) and constant expression throughout lactation (Octn1, Ent2, Ent3, Ncbt1, Ncbt2 & Pept1).These expression patterns will provide insight into the critical windows of nutrient delivery to the breast milk to provide adequate nutritional stimuli to the suckling infant.Furthermore, MEO cultured in an extracellular matrix-rich environment maintained transporter expression at the mRNA level, which underscores the potential of the primary MEO in vitro model system as a screening tool
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".