Neuroimmune Contributions to Maternal Care

Ohio State University, The, Columbus OH

Investigators

Abstract

Pregnancy is a time of significant hormonal change. Pregnancy hormones affect the expectant mother’s immune system to protect the developing fetus and also act on the brain to foster the display of caregiving behaviors that are necessary for the survival and well-being of the offspring. What is unknown is whether hormones are acting on immune cells within the brain itself to regulate maternal behavior. This project will address this gap in knowledge. Uncovering a role for the immune system in maternal behavior could benefit society because many environmental factors, such as infections, inflammation, dietary perturbations, stress, pollutants, and social isolation or instability, shift the activity of the immune system. If the onset of parental behavior relies on immune system action in the brain, then these environmental factors could negatively impact parent-offspring interactions. In humans, the quality of parental caregiving, particularly maternal care, is associated with lifelong health outcomes in both mother and children alike. It would benefit society to better understand the mechanisms that underlie maternal behavior so that policies that increase or optimize maternal behavior (e.g., parental leave, stress-reduction efforts) can be promoted and efforts be made to avoid exposures that can perturb the immune system to potentially compromise parental behavior. Results from this work could fundamentally transform the way we think about the role of the immune system in the body during motherhood. Synergistic broader impacts activities will promote meaningful engagement with research experiences amongst students from historically excluded groups in science at the high school level. Across many species, the transition to parenthood is associated with prominent hormonal changes. During mammalian pregnancy, hormones act on the brain to promote caregiving behaviors that support survival and well-being of offspring. Hormones during pregnancy also contribute to the shift in maternal immune function that is well characterized peripherally, but poorly understood in the brain. The PIs have found that the brain’s immune system shows dramatic modifications during the peripartum period, including decreased microglia number in brain regions relevant to maternal care, as well as a shifted cytokine balance in the brain. Yet there remain fundamental gaps in understanding of the mechanisms driving neuroimmune changes in the maternal brain and how neuroimmune changes impact maternal brain function and behavior. The investigators will use behavioral, neuroanatomical, biochemical, and targeted pharmacological approaches and converging manipulations in both peripartum and reproductively inexperienced female rats to test the central hypothesis that peripartum neuroimmune alterations are linked to pregnancy-related hormones and contribute to the display of maternal care. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.