Minerals in Nutrition and Development

SUMMARY The health and development of the infant is inherently linked to the health of the mother through the absorption and secretion of nutrients. Dietary minerals, including metals (Cu, Zn, Ca, Mn, Fe) are essential nutrients required for all aspects of physiological function. Yet the transport proteins critical for nutrient absorption and

secretion are poorly defined and there is a paucity of functional data in human tissues or in vitro models derived from normal human cells to elucidate how and what adaptations in transporters occur to support pregnancy and lactation. This fundamental gap must be bridged to improve health outcomes for children and

mothers. Our Transport Elucidation Center (TEC) on Minerals In Nutrition and Development (MINeD) will capitalize on our rich scientific, clinical, and mentoring expertise to serve as a hub for discovery, bench-to- bedside translation, and training in the area of human metal transport and nutrient uptake. The initial focus of

the MINeD center will be in the developing gut and adapting maternal intestine and breast. During pregnancy and lactation, drastic remodeling of the mammary gland enables the synthesis and secretion of milk to sustain and nourish the infant. Importantly, transcriptional data from human milk-derived epithelial cells point to a key

role for metal homeostasis. However, given the ethical challenges of acquiring human samples and establishing suitable in vitro models for transport flux studies, a functional understanding of metal transporters and their broader role in nutrient transport during lactogenesis is lacking. In Aim 1, we will address this gap in

knowledge by defining the human ‘transportome’ in lactating mammary epithelium and how it relates to the mammary metallome to elucidate how nutrients are transported into milk. We will use human in vitro organoid models of mammary gland function to identify functional modules of transporters that are synchronously

induced and discretely localized to accomplish transepithelial metal transport. Using gene-editing technology, we will systematically engineer deletions in the SLC family of solute carriers to de-orphanize understudied transporters and reveal potential new roles in milk production and secretion. In Aim 2, complementary studies

using human adult and pediatric duodenal and jejunal enteroids will determine the role of metal transporters in intestinal adaptation and nutrient absorption to support child development, maternal pregnancy and lactation. We will ask how pregnancy- and lactogenic hormones change intestinal proliferation, transporter protein

abundance at the plasma membrane, fat absorption, and metal content and distribution. Aim 3 of MINeD is to build the infrastructure and fundamental discovery pipeline to support future studies on human transporters. MINeD is well positioned to serve as a nexus for collaborations between basic and clinical research, to foster

interactions in the scientific community by sharing knowledge and resources and hosting research-in-progress talks, workshops and seminars in the scientific areas of human transporter physiology, and to promote career development of diverse early career scientists by providing seed funding for innovative projects.