Cardiovascular diseases are among the main causes of morbimortality in the adult population. Among them, hypertension is a leading cause for stroke, heart disease and kidney failure. Also, as a result of arterial wall weakness, hypertension can lead to the development of dissecting aortic aneurysms, a rare but often fatal condition if not readily treated. In this work, we investigated the role of DBC1 in the regulation of vascular function in an ANGII-induced hypertension mouse model. We found that WT and DBC1 KO mice developed hypertension in response to ANGII infusion. However, DBC1 KO mice showed increased susceptibility to develop aortic dissections. The effect was accompanied by upregulation of vascular remodeling factors, including MMP9 and also VEGF. Consistent with this, we found decreased collagen deposition and elastic fiber fragmentation, suggesting that increased expression of MMPs in DBC1 KO mice weakens the arterial wall, promoting the formation of aortic dissections during treatment with ANGII. Finally, DBC1 KO mice had reduced cell proliferation in the intima-media layer in response to ANGII, paralleled with an impairment to increase wall thickness in response to hypertension. Furthermore, VSMC purified from DBC1 KO mice showed impaired capacity to leave quiescence, confirming the in vivo results. Altogether, our results show for the first time that DBC1 regulates vascular response and function during hypertension and protects against vascular injury. This work also brings novel insights into the molecular mechanisms of the development of aortic dissections.General reagents and antibodies. All general reagents and chemicals were purchased from Sigma-Aldrich, including angiotensin II (ANGII, A9525), unless otherwise specified. Lipofectamine RNAiMax, Bradford protein assay reagent, Trizol and SuperScript II RT were bought from Invitrogen. SiRNAs oligos were purchased from Ambion (Negative Control 4390843; HDAC3 4390771) or Invitrogen (DBC1 MSS211964 and SIRT1 MSS234959). Antibodies were purchased from Bethyl (anti DBC1, 434 A), Abcam (anti tubulin 7291, anti BrdU 6326, anti KI67 16667), or Cell Signaling (anti Cyclin D1 9262, anti PCNA 92552). DNase I and Fast SYBR Green were purchased from Roche.Animal handling and experiments. All mice used in this study were maintained at the Institut Pasteur de Montevideo Animal facility (UATE). The experimental protocol was approved by the Institutional Animal Care and Use Committee of the Institut Pasteur de Montevideo (CEUA, Protocol number 014-14). All the studies described were performed according to the methods approved in the protocol and following all international guidelines and legal regulations. WT and whole-body DBC1 KO mice were in a C57BL6/J pure background. DBC1 KO mice were backcrossed into C57BL/6 J for more than 10 generations in order to ensure genetic purity. Mice received standard chow and water ad libitum. Scientific RepoRtS |(2020) 10:6772 | https://doi.negative control, DBC1, HDAC3 and SIRT1 using 25 pmol Lipofectamine RNAiMax. After 24 h...