An RNAi therapeutic targeting hepatic DGAT2 in a genetically obese mouse model of nonalcoholic steatohepatitis

Abstract

Nonalcoholic steatohepatitis (NASH) is a severe liver disorder characterized by triglyceride accumulation, severe inflammation, and fibrosis. With the recent increase in prevalence, NASH is now the leading cause of liver transplant, with no approved therapeutics available. Although the exact molecular mechanism of NASH progression is not well understood, a widely held hypothesis is that fat accumulation is the primary driver of the disease. Therefore, diacylglycerol O-acyltransferase 2 (DGAT2), a key enzyme in triglyceride synthesis, has been explored as a NASH target. RNAi-based therapeutics is revolutionizing the treatment of liver diseases, with recent chemical advances supporting long-term gene silencing with single subcutaneous administration. Here, we identified a hyper-functional, fully chemically stabilized GalNAc-conjugated small interfering RNA (siRNA) targeting DGAT2 (Dgat2-1473) that, upon injection, elicits up to 3 months of DGAT2 silencing (>80%-90%, p < 0.0001) in wild-type and NSG-PiZ "humanized" mice. Using an obesity-driven mouse model of NASH (ob/ob-GAN), Dgat2-1473 administration prevents and reverses triglyceride accumulation (>85%, p < 0.0001) without increased accumulation of diglycerides, resulting in significant improvement of the fatty liver phenotype. However, surprisingly, the reduction in liver fat did not translate into a similar impact on inflammation and fibrosis. Thus, while Dgat2-1473 is a practical, long-lasting silencing agent for potential therapeutic attenuation of liver steatosis, combinatorial targeting of a second pathway may be necessary for therapeutic efficacy against NASH.

Lipid alterations in chronic liver disease and liver cancer

“… 232 Interestingly, in vitro, if DGAT1 is silenced in HCC cells, the cells compensate by upregulating DGAT2. 233 Hence, inhibition of DGAT2 in vivo 234 ameliorated liver steatosis. Another less studied enzyme in the TG synthesis pathway is monoacylglycerol O-acyltransferase, which catalyses the synthesis of TGs, may contribute to hepatic steatosis in vivo 235 , 236 and could be an important therapeutic target for the treatment of NAFLD.…”

A novel NEDD4L-TXNIP-CHOP axis in the pathogenesis of nonalcoholic steatohepatitis

“…S6 B). Next, we knocked down Txnip in hepatocytes using GalNAc conjugated siRNA (targets hepatocytes specifically) 47 , and found that the GalNAc Txnip siRNA results were similar to the Txnip shRNA adenovirus results (Supplementary Fig. S7 ).…”

Positive selection of somatically mutated clones identifies adaptive pathways in metabolic liver disease

“…Each is well known to be important in NASH (Figure 3D). Dgat2 and Gpam are critical enzymes in triglyceride synthesis, and for this reason, Dgat2 is a therapeutic target currently being tested in NASH clinical trials (Calle et al, 2021; Yenilmez et al, 2022). Srebf1 is a major transcriptional regulator of lipogenesis (Briggs et al, 1993; Brown and Goldstein, 1997; Wang et al, 1993).…”