Messenger Ribonucleic Acid Encoding Monocyte Chemoattractant Protein-1 is Expressed by the Ovine Corpus Luteum in Response to Prostaglandin F2α 1

Abstract

To investigate expression of monocyte chemoattractant protein-1 (MCP-1) in the ovine corpus luteum, a partial cDNA was produced by reverse transcription-polymerase chain reaction. This cDNA was 89% identical to that reported for bovine MCP-1 mRNA. In experiment 1, steady-state concentrations of mRNA encoding MCP-1 were measured in pools of luteal tissue collected on Days 3, 6, 9, 12, and 15 of the estrous cycle (estrus = O; n = 4/day). There were no differences in mRNA concentrations for MCP-1 among any of the days studied (p = 0.43). In experiment 2, midluteal-phase corpora lutea were collected from ewes at 0 (untreated), 2, 4, 8, and 16 h after administration of a luteolytic dose of prostaglandin F2alpha (PGF2alpha; n = 4/time point). Concentrations of MCP-1 mRNA were undetectable in untreated controls, were detectable at 2 h post-treatment, had increased 4 and 8 h after administration of PGF2alpha when compared to those at 2 h (p < 0.05), and were decreased 16 h after administration of PGF2alpha when compared to those at 4 h (p < 0.05). In situ hybridization for MCP-1 mRNA combined with immunocytochemical labeling of tissue inhibitor of metalloproteinase-1 (TIMP-1) in large luteal cells was used to determine whether the steroidogenic cells that have PGF2alpha receptors express MCP-1 mRNA in response to PGF2alpha. Messenger RNA encoding MCP-1 and TIMP-1 were not colocalized, indicating that MCP-1 was not expressed by large steroidogenic luteal cells during luteolysis.

Determination of Cell Type Specificity and Estrous Cycle Dependency of Monocyte Chemoattractant Protein-1 Expression in Corpora Lutea of Normally Cycling Rats in Relation to Apoptosis and Monocyte/Macrophage Accumulation1

“…In the present study, we have shown that cells expressing MCP-1 mRNA are steroidogenic luteal cells in normally cycling rats. This conclusion appears to conflict with the results reported by Haworth et al [9], who found that large steroidogenic cells, as assessed immunohistochemically with an antibody recognizing tissue inhibitor of metalloproteinase-1, did not contain MCP-1 mRNA in corpora lutea of prostaglandin F 2␣ -administered sheep. The reasons for this discrepancy are not certain at present, but they could include 1) the fact that small luteal cells in the sheep express MCP-1, 2) a difference in the conditions of the animals (normal rats vs. prostaglandin F 2␣ -treated sheep), or 3) a difference in the antibodies used to identify steroidogenic cells.…”

“…The presence of MCP-1 mRNA or protein in the corpus luteum has been reported for various animal species, including murine [7,12,13], bovine [8,10,14], ovine [8,9], and human [11], but the identity of the cell type(s) responsible for the Mcp-1 gene expression has been ambiguous. In the present study, we have shown that cells expressing MCP-1 mRNA are steroidogenic luteal cells in normally cycling rats.…”

“…Previous studies have shown that immune cells, including monocytes/macrophages and lymphocytes, accumulate, that apoptotic luteal cells increase in number, and that the expression of some cytokines is activated during regression of the corpus luteum [5,6]. In particular, augmented expression of monocyte chemoattractant protein-1 (MCP-1), a C-C chemokine that provokes migration of monocytes/macrophages toward the place of inflammation, in regressive corpora lutea at the mRNA [7][8][9][10][11] and protein [7,[11][12][13][14] levels has been reported by several investigators. However, the possibility that monocytes/macrophages accumulate in corpora lutea because of the action of MCP-1 and play a role in luteolysis has been only speculative.…”

Both Prolactin and Progesterone in Proestrus Are Necessary for the Induction of Apoptosis in the Regressing Corpus Luteum of the Rat1

“…The entrance of macrophages is probably dependent on the release of chemotactic factors TC # 360 from the CL. Previous authors have shown that regressing CL in the rat [10] and sheep [30] express monocyte chemoattractant protein 1 (MCP-1) and that PRL induces the expression of this protein in the CL of the rat [11]. In the present study, macrophage accumulation was not affected by any treatment except CB154, which specifically inhibits PRL secretion.…”

Elevated Plasma Levels of Interleukin 1β, Tumour Necrosis Factor α and Monocyte Chemotactic Protein 1 Are Associated with Pregnancy Toxaemia in Ewes

“…MCP-1 is also normally expressed in the corpus luteum (Tsai et al, 1997) and partially involved in structural and functional luteolysis in humans (Arici et al, 1997), ruminants (Tsai et al, 1997;Townson et al, 2002) and rodents (Bowen et al, 1999). The majority of cells expressing MCP-1 in the corpus luteum are inflammatory cells, including macrophages, which may play a partial role in regression of the corpus luteum since MCP-1 expression in the corpus luteum increases in response to PGF 2α (Haworth et al, 1998). MCP-1 not only serves as a specific chemo-attractant for monocytes but also stimulates the proliferation of vascular smooth-muscle cells and production of cytokines from monocytes and macrophages (Vaddi et al, 1997).…”