The shRNA-mediated PCSK9 knockdown is similar to the findings of an in vitro study that Ad-shHNF1α infection in HepG2 hepatocellular carcinoma cells markedly suppressed PCSK9 mRNA expression and upregulated LDLR protein and that injecting normal diet-fed mice with Ad-shHNF1α significantly suppressed the liver PCSK9 mRNA expression, serum PCSK9, and circulating LDL-C levels while upregulating hepatic LDLR protein expression [49]. Here, PCSK9 is linked to infection.