SIRT6 promotes angiogenesis and hemorrhage of carotid plaque via regulating HIF-1α and reactive oxygen species

Abstract

As a member of Sirtuins family, SIRT6 participates in the physiological and pathological progress of DNA repair, anti-aging, metabolism, and so on. Several studies have demonstrated that knockdown of SIRT6 inhibited the development of atherosclerosis (AS), indicated SIRT6 as a protective factor for AS. However, we confirmed SIRT6 was significantly overexpressed in human unstable carotid plaques compared with stable carotid plaques. This result indicated a more complex role of SIRT6 in AS. Furthermore, we constructed mice model with unstable carotid plaque and injected them with SIRT6 overexpressed adeno-associated virus (AAV-SIRT6). AAV-SIRT6 significantly promoted angiogenesis as well as hemorrhage in plaques. In vitro, we demonstrated overexpression of SIRT6 prevented HIF-1α from degradation by deubiquitination at K37 and K532 of HIF-1α, thus promoted the expression of HIF-1α under both normoxia and hypoxia in human umbilical vein endothelial cells (HUVECs). Through regulating HIF-1α, overexpression of SIRT6 promoted invasion, migration, proliferation, as well as tube formation ability of HUVECs. Interestingly, under different conditions, SIRT6 played different roles in the function of HUVECs. Under oxidative stress, another important pathological environment for AS, SIRT6 bound to the promoter of Catalase, a main reactive oxygen species scavenger, and depleted H3K56 acetylation, thus inhibited expression and activity of Catalase at the transcriptional level. Subsequently, inhibited Catalase promoted reactive oxygen species (ROS) under oxidative stress. Accumulated ROS further aggravated oxidative stress injury of HUVECs. On one hand, SIRT6 promoted angiogenesis in plaque via HIF-1α under hypoxia. On the other hand, SIRT6 promoted injury of neovascular via ROS under oxidative stress. It is this process of continuous growth and damage that leads to hemorrhage in carotid plaque. In conclusion, we innovatively confirmed SIRT6 promoted the angiogenesis and IPH via promoting HIF-1α and ROS in different environments, thus disclosed the unknowing danger of SIRT6.

SIRT6 in Vascular Diseases, from Bench to Bedside

“…Patients with diabetic atherosclerosis showed higher endothelial SIRT6 in plaques following administration of glucagon-like peptide-1 (GLP-1) receptor agonists [ 82 ], revealing endothelial SIRT6 as a curative effect index and target for atherosclerosis treatment. Endothelial SIRT6 facilitates angiogenesis and hemorrhage of carotid plaques by inhibiting HIF-1α and ROS [ 83 ]. Thus, the anti-atherosclerotic role of SIRT6 may also rely on its function in angiogenesis.…”

AAV-mediated gene therapy: Advancing cardiovascular disease treatment

“…The role of SIRT6 was also demonstrated by a preclinical study that involved creating a carotid plaque mouse model. In short, SIRT6 inhibits HIF-1α degradation to stimulate angiogenesisrelated signaling pathways, revealing the cardiovascular risk associated with SIRT6 expression and suggesting that SIRT6 knockout is a feasible route to inhibit the development of atherosclerosis (117).…”

SIRT6 mediates multidimensional modulation to maintain organism homeostasis

“…In another study, overexpression of SIRT6 greatly reduced the oxidative stress of glioma cells and inhibited the activation of the JAK2/STAT3 signaling pathway, thereby inhibiting the growth of glioma cells (Feng et al, 2016). In the development of atherosclerosis, SIRT6 can promote carotid plaque angiogenesis and bleeding by regulating HIF‐1α and reactive oxygen species (Yang et al, 2021). SIRT6 can mediate the demyristoylation of TNF‐α at Lys19 and Lys20 to promote its secretion and participate in the inflammatory response (Liszt et al, 2005).…”