CRISPR-enhanced human adipocyte browning as cell therapy for metabolic disease

Obesity and type 2 diabetes are associated with disturbances in insulin regulated glucose and lipid fluxes and severe comorbidities including cardiovascular disease and steatohepatitis. Whole body metabolism is regulated by lipid-storing white adipocytes as well as 'brown' and 'brite/beige' adipocytes that express thermogenic uncoupling protein 1 (UCP1) and secrete factors favorable to metabolic health. Implantation of immortalized human brown adipocytes into obese mice improves glucose tolerance, but translation to humans has been stymied by low abundance of primary beige adipocytes. Here we applied methods to greatly expand human adipocyte progenitors from small samples of human subcutaneous adipose tissue and then disrupted the thermogenic suppressor gene NRIP1 by CRISPR. SpyCas9 protein/sgRNA complexes delivered ex vivo were fully degraded by the human cells following high efficiency NRIP1KO that markedly elevated the brown-like gene expression profile with no detectable off target editing. Implantation of such CRISPR-enhanced human or mouse 'brown-like' adipocytes into high fat diet fed mice decreased adiposity and liver triglycerides while enhancing glucose tolerance compared to mice implanted with unmodified adipocytes. These findings advance a therapeutic strategy to improve metabolic homeostasis through CRISPR-based genetic enhancement of human adipocyte that does not expose the recipient to immunogenic Cas9 or delivery vectors.