LOXL4 Abrogation Does Not Exaggerate Angiotensin II-Induced Thoracic or Abdominal Aortic Aneurysm in Mice

It has been shown that thoracic aortic aneurysm and dissection (TAAD) could be a Mendelian trait caused by a single gene mutation. The LOX gene mutation leads to the development of human TAAD. The LOXL4 gene is a member of the lysyl oxidase gene family. We identified seven variants in the LOXL4 gene in 219 unrelated patients with TAAD by whole-exome sequencing (WES). To further investigate whether LOXL4 is a candidate causative gene for human TAAD, a Loxl4 knockout mouse was generated, and the mutant mice were treated by subcutaneous infusion of angiotensin II. We found that abrogation of Loxl4 did not induce a more severe thoracic or abdominal aortic aneurysm compared with the wild-type C57BL/6J mice. Our results suggest that LOXL4 may not play a major role in the development of angiotensin II-induced aortic aneurysm. The functional study using this animal model system is important for the evaluation of candidate genes of TAAD identified by WES.