A closed-loop cholesterol shunt controlling experimental dyslipidemia

Hypercholesterolemia is a complex metabolic disorder resulting from dysregulated lipid metabolism and is a significant risk factor for atherosclerosis, coronary artery disease, and myocardial infarction. To address the challenge of dyslipidemia, we present the cholesterol homeostasis and regulation module (CHARM), a designer genetic circuit engineered to sense elevated cholesterol levels in real time and strengthen the innate cholesterol homeostasis machinery. The circuit incorporates a custom fusion protein consisting of the Krüppel-associated box (KRAB) domain and a modified sterol regulatory element (SRE)-binding protein 1a (SREBP1a) as a sensor platform, along with a synthetic expression module containing SRE operator sites downstream of a constitutive promoter that enables the production of a therapeutic protein to reduce low-density lipoprotein cholesterol (LDL-C) levels in a closed-loop fashion. Implantation of microencapsulated CHARM-transgenic human cells in hypercholesterolemic mice rapidly restored and subsequently stably maintained cholesterol homeostasis.