Developmental programming of Kupffer cells by maternal obesity causes fatty liver disease in the offspring [snMultiome sequencing]
Kupffer cells (KCs) are tissue-resident macrophages which colonize the liver early during embryogenesis. KCs start to acquire a tissue-specific transcriptional signature immediately after colonizing the liver, mature together with the tissue, and adapt to the tissue's functions. Throughout development and adulthood, KCs have distinct core functions that are essential for liver and organismal homeostasis, such as supporting fetal erythropoiesis as well as postnatal erythrocyte recycling and liver metabolism. However, whether perturbations of macrophage core functions during development contribute to or cause disease at postnatal stages is poorly understood. Here, we utilize a mouse model of maternal obesity to perturb KC functions during gestation. We show that offspring exposed to maternal obesity develop fatty liver disease, driven by aberrant developmental programming of KCs that persists into adulthood. Programmed KCs mediate lipid uptake by hepatocytes through apolipoprotein secretion. KC depletion in neonates born to obese mothers, followed by replenishment with exogenous monocytes, rescues the fatty liver disease. The transcriptional programming of KCs and the fatty liver disease phenotype are also rescued by genetic depletion of hypoxia-inducible factor alpha (Hif1a) in macrophages during gestation. These results establish developmental perturbation of KC functions as a cause for the development of fatty liver disease in adult life and, thereby, place fetal-derived macrophages as intergenerational messengers within the concept of developmental origins of health and diseases. Overall design: Three-week-old female mice were initially fed with a control diet (CD) for two weeks and were thereafter divided into two groups: one continued on the CD while the other received a high-fat diet (HFD) for eight weeks. The homeostatic model for insulin resistance (HOMA-IR) was used to assess metabolic changes. Mice with higher HOMA-IR on the HFD were selected to create a maternal obesity model and mice fed with CD were used to generated maternal lean offspring. All females were mated with CD males. Offspring born to maternal obese were cross-fostered to generate both lactating groups and offspring born to maternal lean mothers were crossed-fostered by other maternal lean mothers. Male offspring were weaned into CD or HFD postweaning cages. Livers of offspring were harvested at 11-12 weeks. Nuclei were isolated from approximately 50 mg of flash-frozen adult liver tissue to enable simultaneous single-nucleus RNA sequencing (snRNA-seq) and single-nucleus ATAC sequencing (snATAC-seq), capturing both transcriptional profiles and chromatin accessibility.