Discovery of new inducible genes in in vitro decidualized human endometrial stromal cells using microarray technology

A prerequisite for implantation in humans is differentiation (decidualizati on) of stromal cells in the endometrium, believed to be stimulated by proge sterone (P) and/or cAMP. In the current study, advances in microarray techn ology have allowed us to investigate genes differentially expressed in huma n endometrial stromal cells decidualized in vitro in response to P or cAMP, compared to non decidualized cells. Endometrial stromal cells were isolate d from endometrial biopsy tissue and cultured without steroid hormones, wit h 1 mu M P (after E-2 priming), or 1 mM 8-bromo-cAMP. Total RNA was isolate d and reverse transcribed to synthesize P-32-labeled cDNA probes using prim ers corresponding to genes represented on the Clontech Human Atlas cDNA Exp ression Array. After hybridization, signals were quantified by phosphor ima ging densitometry and were normalized to GAPDH and ubiquitin. Of the 588 ge nes screened, marked upregulation was observed of cytokines, growth factors , nuclear transcription factors, members of the cyclin family, and mediator s of the cAMP signal transduction pathway. Additional mRNAs expressed unexp ectedly and regulated by P and cAMP, include the insulin receptor, some neu rotransmitter receptors, neuromodulators, the FSH receptor, inhibin/activin beta(A) subunit, inhibin alpha, and TNF-related apoptosis-inducing ligand (TRAIL). Expression of previously unrecognized genes regulated in deciduali zed human endometrial stromal cells suggests mechanisms not yet appreciated in the endometrium during decidualization. In addition, marked upregulatio n of cytokines, chemokines, growth factors, apoptosis modulators, and their receptors in decidualized stromal cells supports a major role for paracrin e interactions between the stroma and other endogenous and transient cell p opulations within the endometrium and during early pregnancy.