Jarrett KE, Lee CM, Yeh YH, Hsu RH, Gupta R, Zhang M, Rodriguez PJ, Lee CS, Gillard BK, Bissig KD, Pownall HJ, Martin JF, Bao G, Lagor WR.

Sci Rep. 2017 Mar 16;7:44624. doi: 10.1038/srep44624.

Abstract

Germline manipulation using CRISPR/Cas9 genome editing has dramatically accelerated the generation of new mouse models. Nonetheless, many metabolic disease models still depend upon laborious germline targeting, and are further complicated by the need to avoid developmental phenotypes. We sought to address these experimental limitations by generating somatic mutations in the adult liver using CRISPR/Cas9, as a new strategy to model metabolic disorders. As proof-of-principle, we targeted the low-density lipoprotein receptor (Ldlr), which when deleted, leads to severe hypercholesterolemia and atherosclerosis. Here we show that hepatic disruption of Ldlr with AAV-CRISPR results in severe hypercholesterolemia and atherosclerosis. We further demonstrate that co-disruption of Apob, whose germline loss is embryonically lethal, completely prevented disease through compensatory inhibition of hepatic LDL production. This new concept of metabolic disease modeling by somatic genome editing could be applied to many other systemic as well as liver-restricted disorders which are difficult to study by germline manipulation.

See: http://www.nature.com/articles/srep44624

Figure 1: Somatic disruption of Ldlr and Apob. (A) Experimental design- Male C57BL/6 J mice were injected with a total of 6 × 10¹¹ genome copies of AAV, placed on Western Diet, and followed for 20 weeks. (B) Expression of mRNA Ldlr and Apob in the liver using primers upstream and downstream of the gRNA site. (C) LDLR and beta tubulin Western blot in mouse liver. (D) Apo B protein levels in plasma. Uncropped Western blot images are shown in Supplementary Data. For all panels: BbsI control n = 5, Ldlr gRNA + BbsI n = 5, Ldlr + Apob gRNA n = 6; data are represented as mean +/− S.D. and *p < 0.05.