Expression and regulation of secreted phosphoprotein 1 in the bovine corpus luteum and effects on T lymphocyte chemotaxis

Abstract

Secreted phosphoprotein 1 (SPP1) in the bovine corpus luteum (CL) regulates cell function during the transitional periods of luteinization and luteal regression. The objectives were to i) characterize SPP1 expression in the CL throughout the estrous cycle, ii) determine factors that regulate SPP1 expression in luteal cells, and iii) examine the role of SPP1 in lymphocyte chemotaxis, proliferation, and function. SPP1 mRNA was greater in fully functional (d10) CL and late cycle (d18) CL compared with developing (d4) CL. Additionally, SPP1 mRNA increased within 1 h and remained elevated 4 and 8 h following induction of luteolysis with prostaglandin (PG)F 2a . Expression of the SPP1 receptor, b 3 integrin, was not different throughout the estrous cycle but decreased following induction of luteolysis. Expression of CD44 increased during the estrous cycle but did not change during luteal regression. In cultured luteal cells, SPP1 mRNA was upregulated by PGF 2a and/or tumor necrosis factor a. Western blots revealed the presence of both full-length SPP1 and multiple cleavage products in cultured luteal cells and luteal tissue. Depletion of endogenous SPP1 did not hinder luteal cell-induced lymphocyte proliferation or lymphocyte phenotype but did inhibit lymphocyte migration toward luteal cells. Based on these data, it is concluded that SPP1 is initially activated to establish and maintain cellular interactions between steroidogenic and nonsteroidogenic cells during the development of the CL. Upon induction of luteolysis, SPP1 serves as a signaling molecule to recruit or activate immune cells to facilitate luteal regression and tissue degradation.

Luteal Cells from Functional and Regressing Bovine Corpora Lutea Differentially Alter the Function of Gamma Delta T Cells1

“…Interestingly, IL4 and IL10 augment progesterone production from human luteal cells in vitro [11]. The mRNA for IL10 in luteal tissue was more abundant at Day 10 compared to Day 18 of the estrous cycle [42]. In the present study, luteal cells from midcycle CL increased the proportion of cd T cells synthesizing IL10 and decreased the proportion of cd T cells synthesizing IFNG, but increased the proportion of both IL10 þ and IFNG þ cells in the CD4 þ cell population.…”

Genome-Wide Association Analyses Highlight the Potential for Different Genetic Mechanisms for Litter Size Among Sheep Breeds

“…The FLI1 gene encodes a critical transcription factor, which regulates gene ETS1 ( Vo et al, 2017 ). The SPP1 gene accounts for establishing and maintaining cellular interactions between steroidogenic and non-steroidogenic cells during the development of corpus luteum ( Poole et al, 2013 ). In addition, the GO categories as well as protein–protein network and expression analysis showed that these genes played an essential role in follicle growth and ovulation of ewes.…”

Gonadotropin regulation and role of ovarian osteopontin in the periovulatory period

“…OPN transcripts were also detected in bovine ovarian follicles and corpus lutea (Brunswig-Spickenheier & Mukhopadhyay 2003). Recently, results of a detailed study have indicated that OPN is localized in bovine luteal cells during the luteal phase of the estrous cycle and is involved in the development and regression of the corpus luteum (Poole et al 2013). To our knowledge, normal OPN expression in follicular or luteal cells in adult animals has not been reported, except for expression in the bovine ovary.…”