Transcriptional expression of type-I interferon response genes and stability of housekeeping genes in the human endometrium and endometriosis

Abstract

Endometriosis is a painful chronic female disease defined by the presence of endometrial tissue implants in ectopic (Ec) locations. The pathogenesis is much debated, and type-I interferons (IFNs) could be involved. The expression of genes of the type-I IFN response were profiled by a specific PCR array of RNA obtained from Ec and eutopic (Eu) endometrium collected from nine endometriosis patients and nine healthy control women. Transcriptional expression levels of selected IFN-regulated and housekeeping genes (HKGs) were investigated by real-time quantitative reverse transcriptase PCR (qRT-PCR). Stably expressed HKGs for valid normalization of transcriptional studies of endometrium and endometriosis have not yet been published. Here, seven HKGs were evaluated for stability using the GeNorm and NormFinder software. A normalization factor based on HMBS, TBP and YWHAZ expression was suitable for normalization of qRT-PCR studies of Eu versus Ec endometrium. In the endometrial cell lines HEC1A, HEC1B, Ishikawa and RL95-2, HMBS and HPRT1 were the most stably expressed. The IFN-specific PCR array indicated significantly different expression of the genes BST2, COL16A1, HOXB2 and ISG20 between the endometrial tissue types. However, by correctly normalized qRT-PCR, levels of BST2, COL16A1 and the highly type-I IFN-stimulated genes ISG12A and 6-16 displayed insignificant variations. Conversely, HOXB2 and ISG20 transcriptions were significantly reduced in endometriosis lesions compared with endometrium from endometriosis patients and healthy controls. In conclusion, appropriate HKGs for normalization of qRT-PCR studies of endometrium and endometriosis have been identified here. Abolished expression of ISG20 and HOX genes could be important in endometriosis.

Expression of miR-126 and Crk in endometriosis: miR-126 may affect the progression of endometriosis by regulating Crk expression

“…Our present study confirmed that ECs expresses less miR-126 than EUs, further validating the results of previous miRNA profiling studies of EMs [25,[32][33][34]. The present study may provide initial evidence that miR-126 may participate [35,36]. However, previous studies indicated that the differential expression profiles of miRNA in EMs might play an incipient role in aberrant gene expression in endometrium, priming it to become a new target of investigation [25,[31][32][33][34].…”

Virus Infection and Type I Interferon in Endometriosis

“…The possible involvement of type I IFNs in endometriosis has recently been investigated directly (Vestergaard et al, 2011). A type I interferon-specific PCR Array indicated significantly down-regulated transcription of the genes HOXB2 and ISG20 in endometriosis lesions compared with endometrium from endometriosis patients and healthy controls, but no difference in the expression of any other interferon stimulated genes were observed.…”

“…The transcriptional expression of ISG20 (interferon-stimulated gene product of 20 kDa, also called HEM45) was shown by validated qRT-PCR to be highly down-regulated in endometriosis lesions (Vestergaard et al, 2011). ISG20 transcription is induced synergistically by type I and II IFNs, induced by estrogen, and regulated in a progesteronedependent manner in mice, especially in the mouse endometrium.…”

“…A very solid down-regulation of HOXB2 in endometriotic lesions compared with endometrium from both endometriosis and healthy women has been observed (Vestergaard et al, 2011). Little is known about HOXB2 expression in the endometrium, but several studies have demonstrated that HOXB2 expression is altered in tumours.…”

“…However, a more in-depth analysis correlated lower HOXB2 expression with higher grades of tumours. Finally, it has been reported that the HOXB2 protein binds the interferon-induced protein p205, involved in the growth inhibitory activities of interferon (see Vestergaard et al, 2011). Whether HOXB2 interaction with p205 modifies the growth inhibitory activities of p205 has not yet been investigated.…”