Secretion and hormonal regulation of interleukin-6 production by mouse uterine stromal and polarized epithelial cells cultured in vitro.

Abstract

Uterine stromal (USC) and uterine epithelial (UEC) cells were isolated from immature and mature mice to determine their ability to secrete interleukin-6 (IL-6) in response to ovarian steroids, IL-1 alpha, and soluble products produced by the heterologous cell type. In addition, the effect of IL-6 on embryo attachment and outgrowth in vitro was determined. UEC cultured on nitrocellulose filter inserts in a polarized manner secreted IL-6 with a 2.5- to 5-fold apical vs. basal preference, as determined by a B9 hybridoma cell proliferation assay and enzyme-linked immunosorbent assay. The hormonal status of animals at the time uteri were removed did not influence subsequent secretion of IL-6, as UEC isolated from immature, diestrous, and estrous stage mice exhibited both a similar amount and had a similar apical preference for secretion of IL-6. The addition of 17 beta-estradiol (E) to UEC cultures markedly inhibited total IL-6 secretion, but did not affect vectorial secretion. The inhibitory effect of E on IL-6 secretion by UEC was consistent with an apparent decrease in IL-6 transcript observed by a reverse transcriptase polymerase chain reaction assay. Other transcripts detected by this assay in UEC included IL-1 alpha, but not IL-1 beta or tumor necrosis factor-alpha. Secretion of IL-6 by UEC was not stimulated by IL-1 alpha, conditioned medium from USC, or coculture with USC. USC secreted IL-6, and while this also was inhibited by E, progesterone was more effective in this regard at physiological concentrations. In addition, there was a synergistic effect of E plus progesterone on inhibition of IL-6 secretion by USC. Secretion of IL-6 by USC was stimulated by IL-1 alpha, and coculture studies demonstrated the ability of UEC to stimulate a several-fold increase in IL-6 secretion by USC. The cytokine transcripts detected in USC cultures included IL-6 and IL-1 alpha, but not IL-1 beta. Transcripts for tumor necrosis factor-alpha were present in USC only after culture with IL-1 alpha. IL-6 added to blastocysts on laminin-coated tissue culture wells resulted in a transient inhibition of the rate of blastocyst attachment and, to a greater extent, an inhibition of the rate of embryo outgrowth. In addition, IL-6 inhibited the size of embryo outgrowths at 24 and 48 h of culture.(ABSTRACT TRUNCATED AT 400 WORDS)

Interleukin‐6 an endocrine cytokine

“…Oestrogens are also known to inhibit IL-6 production by osteoblasts and stromal cells derived from bone marrow and by breast carcinoma cells (Speirs et al, 1993). Uterine epithelial cells have been shown to augment the release of IL-6 from the stromal cells implicating a potential paracrine interaction (Jacobs et al, 1992). Significantly, in this study, IL-6 was shown to inhibit the size of embryo outgrowths in culture.…”

“…In the mouse and human uterus, the uterine stromal cells or fibroblasts and uterine epithelial cells have been identified as the sources of IL-6 (Tabibzadeh et al, 1989;Jacobs et al, 1992).…”

“…There is polarization of IL-6 secretion in the uterus with apical epithelial cells secreting greater amounts than basal uterine cells (Jacobs et al, 1992). The secretion of IL-6 from these cells can be inhibited by 17P-oestradiol and stimulated by IL-I (Tabibzadeh et al, 1989;Jacobs et al, 1992).…”

“…The secretion of IL-6 from these cells can be inhibited by 17P-oestradiol and stimulated by IL-I (Tabibzadeh et al, 1989;Jacobs et al, 1992). Oestrogens are also known to inhibit IL-6 production by osteoblasts and stromal cells derived from bone marrow and by breast carcinoma cells (Speirs et al, 1993).…”

Relationship between cytokines and the embryotoxicity of hydrosalpingeal fluid

“…The cytokine, which appears to mediate numerous physiologic and pathogenic processes, acts on a wide variety of cells and regulated immune responses, acute-phase responses of the liver, hematopoiesis, neuronal functions, and osteoclastogenesis (21). The cytokine may also have important functions in reproductive physiology, including the regulation of ovarian steroid production, folliculogenesis, and early events related to implantation (22,23). The fact that I L-6 is positively correlated with BDR may explain in part, why some hydrosalpingeal fluid samples are not embryotoxic.…”