Comparison in gene expression of secretory human endometrium using laser microdissection

Abstract

Background: The endometrium prepares for implantation under the control of steroid hormones. It has been suggested that there are complicated interactions between the epithelium and stroma in the endometrium during menstrual cycle. In this study, we demonstrate a difference in gene expression between the epithelial and stromal areas of the secretory human endometrium using microdissection and macroarray technique.

Methods: The epithelial and stromal areas were microdissected from the human endometrium during the secretory phase. RNA was extracted and amplified by PCR. Macroarray analysis of nearly 1000 human genes was carried out in this study. Some genes identified by macroarray analysis were verified using real-time PCR.

Results: In this study, changes in expression <2.5-fold in three samples were excluded. A total of 28 genes displayed changes in expression from array data. Fifteen genes were strongly expressed in the epithelial areas, while 13 genes were strongly expressed in the stromal areas. The strongly expressed genes in the epithelial areas with a changes >5-fold were WAP four-disulfide core domain 2 (44.1 fold), matrix metalloproteinase 7 (40.1 fold), homeo box B5 (19.8 fold), msh homeo box homolog (18.8 fold), homeo box B7 (12.7 fold) and protein kinase C, theta (6.4 fold). On the other hand, decorin (55.6 fold), discoidin domain receptor member 2 (17.3 fold), tissue inhibitor of metalloproteinase 1 (9 fold), ribosomal protein S3A (6.3 fold), and tyrosine kinase with immunoglobulin and epidermal growth factor homology domains (5.2 fold) were strongly expressed in the stromal areas. WAP four-disulfide core domain 2 (19.4 fold), matrix metalloproteinase 7 (9.7-fold), decorin (16.3-fold) and tissue inhibitor of metalloproteinase 1 (7.2-fold) were verified by real-time PCR.

Conclusions: Some of the genes we identified with differential expression are related to the immune system. These results are telling us the new information for understanding the secretory human endometrium.

Figure 1

Human endometrial epithelial areas (a-b) and stromal areas (c-d) were laser-microdissected. (200×)

Figure 2

A: WFDC2 mRNA expression in the secretory phase of the endometrium was determined by real-time PCR (n = 5). Values were normalized to GAPDH mRNA expression. Epithelial areas WFDC2 mRNA expression is shown relative to that of the stromal areas. The mean change is 19.4-fold. Statistical analysis was carried out using Wilcoxon test. B: MMP7 mRNA expression in the secretory phase of the endometrium was determined by real-time PCR (n = 5). Values are normalized to GAPDH mRNA expression. Epithelial areas MMP7 mRNA expression is shown relative to that of the stromal areas. The mean change is 9.7-fold. Statistical analysis was carried out using Wilcoxon test. C: Decorin mRNA expression in the secretory phase of the endometrium was determined by real-time PCR (n = 5). Values were normalized to GAPDH mRNA expression for each sample. Stromal areas decorin mRNA expression is shown relative to that of the epithelial areas. The mean change is 16.3-fold. Statistical analysis was carried out using Wilcoxon test. D: TIMP1 mRNA expression in the secretory phase of the endometrium was determined by real-time PCR (n = 5). Values are normalized to GAPDH mRNA expression for each sample. Stromal areas TIMP1 mRNA expression is shown relative to that of the epithelial areas. The mean change is 7.2-fold. Statistical analysis was carried out using Wilcoxon test.