PARENT SESSION
BIOLOGY OF PREGNANCY AND IMMUNE FUNCTION
Harborside C
7:30 AM-10:00 AM

(317) PREGNANCY-DEPENDENT SPLENOMEGALY AND SPLENIC GENE EXPRESSION.

Alt, Adam¹, Dai, Guoli¹, Peal, Mary¹, Ain, Rupasri¹, Soares, Michael¹, ¹ Department of Molecular and Integrative Physiology, Kansas City, KS

ABSTRACT- Viviparity necessitates immunological and hematological adjustments in the mother. The embryo has the potential to evoke an immune response and pregnancy is characterized by increased demands on the hematopoietic system. Requirements for controlling these important processes change during gestation and must be coordinated with the needs of the developing placenta and fetus. Central to the regulation of these key processes is the spleen. The spleen serves two major functions. It is a major site for mounting immune responses and it is the site for the destruction of senescent and compromised red blood cells. The nature and regulation of adjustments in the spleen during pregnancy are not understood. In this investigation, the influence of pregnancy on splenic growth and gene expression was examined. Tissues were collected from various stages of gestation. Dynamic changes were observed in the size of the maternal spleen during pregnancy, especially when compared to pregnancy-dependent changes in other maternal organs. Growth of the spleen was initiated following implantation, peaked at day 13 of gestation, and then regressed to the nonpregnant state by term. The growth phase correlated with placentation and the elaboration of members of the placental prolactin family. Significant structural changes in the organization of spleen were apparent at the light microscope level. Prominent pregnancy-dependent changes were observed in the ratio of red pulp to white pulp and the size of the marginal zones. Gene expression profiles were compared between spleens from nonpregnant and pregnant mice using a DNA microarray strategy. Data from three independent DNA microarray analyses were collected. Pregnancy significantly influenced splenic gene expression, including genes encoding proteins involved in regulating cell proliferation, differentiation, and survival and extracellular matrix remodeling. Additionally, differential expression of genes encoding cell surface proteins suggested a redistribution of the cellular constituents of the spleen. In summary, the spleen of the mouse exhibits dynamic changes in its size and function during pregnancy. (Supported by the American Heart Association, the Andrew Mellon Foundation, and the NICHD: HD20676, HD37123)

KEY WORDS: gene expression, spleen, pregnancy, splenomegaly