Angiotensin II induces Fat1 expression/activation and vascular smooth muscle cell migration via Nox1-dependent reactive oxygen species generation

Abstract

Fat1 is an atypical cadherin that controls vascular smooth muscle cell (VSMC) proliferation and migration. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 1 (Nox1) is an important source of reactive oxygen species (ROS) in VSMCs. Angiotensin II (Ang II) induces the expression and/or activation of both Fat1 and Nox1 proteins. This study tested the hypothesis that Ang II-induced Fat1 activation and VSMC migration are mediated by Nox1-dependent ROS generation and redox signaling. Studies were performed in cultured VSMCs from Sprague-Dawley rats. Cells were treated with Ang II (1 μmol/L) for short (5 to 30 min) or long term stimulations (3 to 12 h) in the absence or presence of the antioxidant apocynin (10 μmol/L), extracellular-signal-regulated kinases 1/2 (Erk1/2) inhibitor PD98059 (1 μmol/L), or Ang II type 1 receptor (AT1R) valsartan (1 μmol/L). siRNA was used to knockdown Nox1 or Fat1. Cell migration was determined by Boyden chamber assay. Ang II increased Fat1 mRNA and protein levels and promoted Fat1 translocation to the cell membrane, responses that were inhibited by AT1R antagonist and antioxidant treatment. Downregulation of Nox1 inhibited the effects of Ang II on Fat1 protein expression. Nox1 protein induction, ROS generation, and p44/p42 MAPK phosphorylation in response to Ang II were prevented by valsartan and apocynin, and Nox1 siRNA inhibited Ang II-induced ROS generation. Knockdown of Fat1 did not affect Ang II-mediated increases in Nox1 expression or ROS. Inhibition of p44/p42 MAPK phosphorylation by PD98059 abrogated the Ang II-induced increase in Fat1 expression and membrane translocation. Knockdown of Fat1 inhibited Ang II-induced VSMC migration, which was also prevented by valsartan, apocynin, PD98059, and Nox1 siRNA. Our findings indicate that Ang II regulates Fat1 expression and activity and induces Fat1-dependent VSMC migration via activation of AT1R, ERK1/2, and Nox1-derived ROS, suggesting a role for Fat1 downstream of Ang II signalling that leads to vascular remodelling.

MAPK activation andHRASmutation identified in pituitary spindle cell oncocytoma

“…Case 1 contained a mutation in the tumor suppressor FAT1 atypical cadherin gene, which has been implicated in glioblastoma, colorectal adenocarcinoma, and head and neck squamous cell carcinoma [15]. While FAT1 is best known for promoting Wnt signaling, FAT1 expression has also been associated with ERK activation [21]. Therefore, mutations in HRAS , SND1 , and FAT1 may constitute separate genetic drivers that underlie the common MAPK activation observed in each SCO.…”

Rho/ROCK Signal Cascade Mediates Asymmetric Dimethylarginine-Induced Vascular Smooth Muscle Cells Migration and Phenotype Change

“…Recently, accumulating evidences have demonstrated that MAPK may be involved in VSMCs migration [14–17]. Zhan et al have revealed that dominant-negative mutants of MAPK, including JNK, ERK, and p38, significantly decreased PDGF-BB–induced VSMC migration [17].…”

Angeli's Salt, a nitroxyl anion donor, reverses endothelin-1 mediated vascular dysfunction in murine aorta

“…VSMC primary cells were used in determining ROS and O2 − generation with dihydroethidium (DHE, Invitrogen, California), which oxidizes in the presence of ROS, generating fluorescence (Bruder-Nascimento et al , 2014; Silva et al , 2015). VSMCs were grown to confluence, and then seeded to 6-well plates.…”