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Abstract The hepatocytes within the liver present an immense capacity to adapt to changes in nutrient availability. Here, by using high resolution volume electron microscopy, we map how hepatic subcellular spatial organization is regulated during nutritional fluctuations and as a function of liver zonation. We identify that fasting leads to remodeling of endoplasmic reticulum (ER) architecture in hepatocytes, characterized by the induction of single rough ER sheet around the mitochondria, which becomes larger and flatter. These alterations are enriched in periportal and mid-lobular hepatocytes but not in pericentral hepatocytes. Gain- and loss-of-function in vivo models demonstrate that the Ribosome receptor binding protein1 (RRBP1) is required to enable fasting-induced ER sheet-mitochondria interactions and to regulate hepatic fatty acid oxidation. Endogenous RRBP1 is enriched around periportal and mid-lobular regions of the liver. In obesity, ER-mitochondria interactions are distinct and fasting fails to induce rough ER sheet-mitochondrion interactions. These findings illustrate the importance of a regulated molecular architecture for hepatocyte metabolic flexibility.

For young women, im/migration can impact education, employment, and family dynamics in ways that shape the courses of their lives and health. The purpose of this study is to deepen understandings of how im/migration shapes young women's experiences of pregnancy, motherhood, and marriage. Guided by intersectionality theory and the structural and social determinants of health, we analyzed qualitative interviews conducted with young im/migrants ages 15-30, who identify as women, and who had experiences of pregnancy, motherhood, and/or marriage (N ​= ​34). Participants were interviewed as part of the IRIS study in British Columbia, Canada between May 2019 to February 2021. Young im/migrant women described how im/migration shaped experiences of pregnancy, motherhood, and marriage by way of health, social, legal, and economic drivers. These included being ineligible for health insurance and unable to prevent pregnancy and experiencing workplace discrimination in form of reduced hours and no maternity benefits. Demanding caregiving roles and unsafe home environments were also described as being exacerbated by unaffordable childcare in destination settings and unequal gender roles and power dynamics after im/migration. Our findings suggest structural changes necessary to improve young im/migrant women's health. We recommend that health systems decouple im/migration status from health insurance; that governments provide all people with accessible childcare and maternity benefits; and that governments fund community-based efforts towards dismantling structures of patriarchy.