Developmental programming of Kupffer cells by maternal obesity causes fatty liver disease in the offspring II

Kupffer cells (KCs) are tissue-resident macrophages which colonize the developing liver early during embryogenesis1. 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 metabolism2. KCs acquire their tissue-specific transcriptional signature immediately after colonizing the liver, mature together with the tissue, and adapt to the tissue’s function1,3,4. However, whether perturbation of macrophage core functions during development may contribute to or cause disease at postnatal stages is poorly understood. Here, we utilize a maternal obesity model to disturb KC functions during gestation. We show that offspring born to obese mothers develop fatty liver disease that is accompanied by a local pro-inflammatory response, a phenotype that is augmented if the offspring is kept on control diet after birth. Further, transcriptional analyses reveal that KCs undergo developmental programming through the maternal high-fat diet, which lasts until adulthood. The offspring’s KC developmental programming is irreversible despite the switch to control diet and leads to increased lipid uptake in hepatocytes mediated via paracrine factors stemming from KCs. The transcriptional programming of KCs and the fatty liver disease phenotype are rescued by genetic depletion of hypoxia-inducible factor alpha (Hif1a) in macrophages during gestation. These results demonstrate that macrophages rely on an undisturbed development to fulfil their core functions and support organ homeostasis during adulthood, and establish developmental programming of KCs as a therapeutic strategy for metabolic disorders, such as fatty liver disease. 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 of age and subsequently dissociated into single-cell suspension. Kupffer cells were then sorted using flurescence-activated cell sorting on an BD FACSAria lII cell sorter directly into 500μl QIAzol lysis buffer (Qiagen) and proceeded for sequencing using SMART-Seq2 protocol.