Next, 8-week-old male ATF4Lyz2KO and their littermate ATF4fl/fl mice were subjected to a single intravenous injection of AAV expressing a gain-of-function mutation of mouse PCSK9 (mPCSK9 D377Y) and fed a western diet, followed by AngII infusion to induce AAA (Fig. 5C). Here, PCSK9 is linked to triple-A syndrome.