Model of the Caruncular Cell Proliferation in Bovine and Gene Expression Profiling in the Model.

Abstract

Implantation starts in caruncular area in bovine endometrium, and endometrial stromal cells entirely proliferates in caruncular area compare to that in inter-caruncular area. The responsible factors and molecules for this phenomenon have been vague. In-vivo condition, various factors may be participated in this issue, therefore development of simplified analytical methods may be a key to understand this complicated events in fetal-maternal interface. First we try to raise the cell lines which have different proliferative activities. A fibroblast cell line (F) derived from bovine endometrium showed lower growth activity compare to a fibroblast cell line (COT) which is originated from cotyledonary tissues. The rate of proliferation in F was one third of that in COT, and F cell was terminated after 36 passages however COT cell has been proliferated around 60 passages. Genes expression profile in both cell lines were assessed by a custom-made bovine oligo-microarray which involved 15k genes information, and about 90-upregulated genes were found in COT compare to that in F. These genes included; cellular retinoic acid binding protein 1, tissue factor pathway inhibitor 2, selectin P, etc. Under serum starvation, both cells arrested within 48 hrs with about 90% G0/G1 phase. Both cells showed the down-regulation in about 1300 genes under starvation, and commonly 9 down-regulated cyclin related genes under arrested condition. Four out of nine these genes were also found as down-regulated genes in senescence condition (terminated at 36 passages) in F cell. We used these for analyzing stimulation factors under serum starvation. In the present study, transforming growth factor-beta (TGF-beta), activin, folistatin, fibroblast growth factor (FGF), heparin-binding EGF-like growth factor (HB-EGF), extract from chorion, extract from bovine trophoblast cell (BT-1), etc. Activin and HB-EGF stimulated F cell proliferation up to about 1.5 fold and extract from both chorion and BT-1 also stimulated 1.2-1.6 folds, TGF-beta and FGF stimulated only 1.2-1.3 folds. This cell was stimulated to 1.4 folds with 10 % bovine calf sera as a positive control. These data suggest that these cell lines may supply an appropriate model for screening initial factor in endometrial cell specific cell proliferation. Supported by a Research Project for Utilizing Advanced Technologies (05-1770) grant from the MAFF of Japan; grants (Kiban-kenkyu B 17380172, Kiban-kenkyu C 19580335) from Ministry of Education, Culture, Sport, Science and Technology of Japan; and a grant from the Animal Remodeling Project (05-201) in the NIAS.