Deficiency of ASGR1 in pigs recapitulates reduced risk factor for cardiovascular disease in humans

Abstract

Genetic variants in the asialoglycoprotein receptor 1 (ASGR1) are associated with a reduced risk of cardiovascular disease (CVD) in humans. However, the underlying molecular mechanism remains elusive. Given the cardiovascular similarities between pigs and humans, we generated ASGR1-deficient pigs using the CRISPR/Cas9 system. These pigs show age-dependent low levels of non-HDL-C under standard diet. When received an atherogenic diet for 6 months, ASGR1-deficient pigs show lower levels of non-HDL-C and less atherosclerotic lesions than that of controls. Furthermore, by analysis of hepatic transcriptome and in vivo cholesterol metabolism, we show that ASGR1 deficiency reduces hepatic de novo cholesterol synthesis by downregulating 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), and increases cholesterol clearance by upregulating the hepatic low-density lipoprotein receptor (LDLR), which together contribute to the low levels of non-HDL-C. Despite the cardioprotective effect, we unexpectedly observed mild to moderate hepatic injury in ASGR1-deficient pigs, which has not been documented in humans with ASGR1 variants. Thus, targeting ASGR1 might be an effective strategy to reduce hypercholesterolemia and atherosclerosis, whereas further clinical evidence is required to assess its hepatic impact.

ASGR1: an emerging therapeutic target in hypercholesterolemia

“…Earlier studies have suggested that ASGR1 reduction increases LDLR and thus lowers blood cholesterol. For example, Xie et al 4 generated Asgr1 -deficient pigs and found that when fed a high-fat and high-cholesterol diet for 6 months, these knockout pigs had lower levels of non-HDL than control pigs. To determine the mechanism of action, Xie et al analyzed the hepatic transcriptomic profile and in vivo cholesterol metabolism and found that ASGR1 deficiency downregulated HMGCR but upregulated hepatic LDLR.…”

Advance of genetically modified pigs in xeno-transplantation

“…Paris and his colleagues( Paris et al, 2011 ) knocked down ASGR1 to reduce ASGR1 expression in asynchronous primary enriched liver sinusoidal endothelial cells (eLSEC) and cripple the ability of primary porcine eLSEC to bind and phagocytose human platelets. Xie’s group( Xie et al, 2021 ) produced ASGR1-deficient pigs using the CRISPR/Cas9 system. The ASGR1-deficient pigs unexpectedly exhibited mild to moderate liver injury, which has not been reported in humans with ASGR1 variants.…”

Advances in CRISPR-Based Functional Genomics and Nucleic Acid Detection in Pigs

“…The development of high-precision genome editing tools, such as targeted nucleases, has accelerated advances in fundamental human medicine, animal science, animal breeding, as well as disease diagnosis ( Doudna and Charpentier, 2014 ; Kurtz et al, 2021 ; Rieblinger et al, 2021 ; Xie et al, 2021 ). In particular, the genome editing system known as CRISPR technology has grown rapidly since it was first reported ( Jinek et al, 2012 ) and has become one of the most popular technologies.…”