Research Interests

Major Research Interests: We are interested in advancing endometrial health and helping treat preganancy complications by targeting resident natural killer cells in the female reproductive tract.

Mammalian reproductive success depends on the optimal development and vascular perfusion of a placenta. Abnormal placental vascularization accompanies obstetrical syndromes, such as preeclampsia, an acute hypertensive disorder that affects 2-7% of pregnancies and is diagnosed by onset of high blood pressure in second trimester. Currently, the only treatment available for preeclampsia is delivery of the baby, often preterm. Epidemiological studies associate preeclampsia susceptibility with the genotype for receptors on maternal natural killer (NK) cells and their cognate HLA class I (HLA-I) ligands expressed on fetal cells. Uterine NK (uNK) cells dominate the maternal-fetal interface and aid in vascular remodeling of the placenta. The molecular mechanisms for these findings remain incompletely understood.

NK cells are the founding members of a growing family of cells called innate lymphoid cells (ILCs). Most insight on NK cells is based on studying NK cells from mouse spleen and human peripheral blood. It is now evident that NK cells can be found resident in tissues and are distinct from the conventional NK (cNK) cells in the spleen. Our organ of interest, the murine uterus, has two populations of NK cells, circulating cNK cells and an abundant tissue-resident NK (trNK) cell population. During pregnancy 70% of the lymphocytes at the maternal-fetal interface are uNK cells. In early pregnancy, trNK cells remained resident and expanded locally while cNK cells contributed minimally to the increasing pool of uNK cells.  We use several novel mouse models to provide insight into the development, differentiation, migration and effector function of uNK cell subsets in the virgin uterus and at the maternal-fetal interface. Better understanding of uNK cell biology will provide insight into their role in maternal health and enhance future studies into their clinical effects.

Publications

Sojka DK, Uterine Natural Killer Cell Heterogeneity: Lessons from Mouse Models. Front Immunol. 2020: Feb 21 

Sojka DK, Yang L, Yokoyama WM, Uterine Natural Killer Cells. Front Immunol. 2019: May 1

Sojka DK, Yang L, Yokoyama WM, Uterine Natural Killer Cells: To Protect and to Nurture. Birth Defects Res. 2018: Nov.22

Sojka DK, Yang L, Plougastel-Douglas B, Higuchi DA, Croy BA, Yokoyama WM, Local Proliferation of Uterine Tissue-Resident Natural Killer Cells During Decidualization in Mice.  J. Immunol, Cutting Edge. 2018: 1;201(9):2551-2556

McCarthy R, Martin-Fairey C, Sojka DK, Herzog ED, Jungheim ES, Stout MJ, Fay JC, Mahendroo M, Reese J, Herington JL, Plosa EJ, Shelton EL, England SK, Mouse models of preterm birth: suggested assessment and reporting guidelines. Biology of Reproduction. 2018: May 3

Sojka DK, Plougastel-Douglas B, Yang L, Pak-Wittel MA, Artyomov MN, Ivanova Y, Zhong C, Chase JM, Rothman PB, Yu J, Riley JK, Zhu J, Tian Z, Yokoyama WM, Tissue-resident natural killer (NK) cells are cell lineages distinct from thymic and conventional splenic NK cells. eLIFE 2014: 3:01659

Sojka DK, Tian Z, Yokoyama WM, Tissue-resident natural killer cells and their potential diversity.  Semin Immunol. 2014: 26: 127-31