Establishment and evaluation of a stable steroidogenic caprine luteal cell line

Many physiological, biological, pharmacologic, and toxicologic events and compounds affect the function of Saanen dairy goat luteal cells, resulting in implantation failure or early embryonic loss. Although primary luteal cell cultures have been used, their finite lifespan precludes assessment of long-term effects. In the present study, primary caprine luteal cells (CLCs) were immortalized through transfection of a plasmid containing the human telomerase reverse transcriptase (hTERT) gene. The expression of hTERT and telomerase activity were evaluated in transduced CLCs (hTERT-CLCs). In this study, these cells steadily expressed hTERT gene and exhibited higher telomerase activity at Passages 30 and 50. The hTERT-CLCs at Passages 30 and 50 expressed genes encoding key proteins, enzymes and receptors inherent to normal luteal cells, e.g., steroidogenic acute regulatory protein (StAR), cytochrome P450 cholesterol side-chain cleavage enzyme (P450scc), 3β-hydroxysteroid dehydrogenase (3β-HSD), and LH-receptor (LH-R). In addition, immortalized caprine luteal cells produced detectable quantities of progesterone in response to 8-bromo-cAMP (8-Br-cAMP) or 22(R)-hydroxycholesterol (22R-HC) stimulation. Furthermore, this cell line appeared to proliferate more quickly than control cells, although no neoplastic transformation occurred either in vivo or in vitro. We concluded the immortalized CLCs by hTERT retained their original characteristics and may provide a useful model to study luteal cell functions.