Nonvesicular sterol transport is a metabolic immune checkpoint that guards dietary lipid uptake (scRNA-Seq)

The intrinsic pathways that control membrane organization in immune cells and the impact of such pathways on cellular functions are not well defined. Here we show that the nonvesicular cholesterol transporter Aster-A links plasma membrane (PM) cholesterol availability in T cells to immune signaling and systemic metabolism. Aster-A is recruited to the PM during T-cell receptor (TCR) activation, where it facilitates the removal of newly generated “accessible” cholesterol. Loss of Aster-A leads to excess PM cholesterol accumulation, resulting in enhanced TCR nano-clustering and signaling, and in Th17 cytokine production. Furthermore, Aster-A associates with STIM1 and negatively regulates STIM1-dependent calcium flux during activation of mouse and human T cells. Finally, mucosal Th17 response towards commensals is restrained by PM cholesterol remodeling. Ablation of Aster-A in T cells stimulates IL-22 production, which reduces intestinal fatty acid absorption, and confers resistance to diet-induced obesity. These findings delineate a multi-tiered regulatory scheme linking immune cell lipid flux to nutrient absorption and systemic physiology. Overall design: Mice were fasted for 16 h and gavaged with olive oil for 2 h. Small intestine lamina propria mononuclear cells were isolated using the method described in the bulk mRNA sequencing section. Single Live EPCAM- Ter119- CD31- CD45+ cells were sorted from 10- to 12-week-old female littermates (n = 3 /genotype) on a BD Aria FACS sorter. 100,000 cells were sorted from each mouse and pooled together.