Biomechanical and biochemical regulation of cathepsin K expression in endothelial cells converge at AP-1 and NF-kappa B

• Type of Material: Article
• Authors: Philip M Keegan, Emory University; Suhaas Anbazhakan, Emory University; Baolin Kang, Georgia Regents University; Betty S Pace, Georgia Regents University; Manu Platt, Emory University
• Language: English
• Date: 2016-05-01
• Publisher: WALTER DE GRUYTER GMBH
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2016 by De Gruyter
• Final Published Version (URL): http://dx.doi.org/10.1515/hsz-2015-0244
• Title of Journal or Parent Work: BIOLOGICAL CHEMISTRY
• Volume: 397
• Issue: 5
• Start Page: 459
• End Page: 468
• Grant/Funding Information: This work was supported by the National Institutes of Health [1DP2OD007433-01 to M.O.P] and also by a National Science Foundation Graduate Research Fellowship to P.M.K.
• Keywords: shear stress; V ACTIVITY; ADHESION; DISEASE; Life Sciences & Biomedicine; PATHOPHYSIOLOGY; proteases; SHEAR-STRESS; sickle cell disease; INHIBITION; VASOOCCLUSION; Science & Technology; TNF-alpha; FLOW; ACTIVATION; STROKE; Biochemistry & Molecular Biology

Abstract

Cathepsins K and V are powerful elastases elevated in endothelial cells by tumor necrosis factor-α (TNFα) stimulation and disturbed blood flow both of which contribute to inflammation-mediated arterial remodeling. However, mechanisms behind endothelial cell integration of biochemical and biomechanical cues to regulate cathepsin production are not known. To distinguish these mechanisms, human aortic endothelial cells (HAECs) were stimulated with TNFα and exposed to pro-remodeling or vasoprotective shear stress profiles. TNFα upregulated cathepsin K via JNK/c-jun activation, but vasoprotective shear stress inhibited TNFα-stimulated cathepsin K expression. JNK/c-jun were still phosphorylated, but cathepsin K mRNA levels were significantly reduced to almost null indicating separate biomechanical regulation of cathepsin K by shear stress separate from biochemical stimulation. Treatment with Bay 11-7082, an inhibitor of IκBα phosphorylation, was sufficient to block induction of cathepsin K by both pro-remodeling shear stress and TNFα, implicating NF-κB as the biomechanical regulator, and its protein levels were reduced in HAECs by vasoprotective shear stress. In conclusion, NF-κB and AP-1 activation were necessary to activate cathepsin K expression in endothelial cells, highlighting integration of biochemical and biomechanical stimuli to control cathepsins K and V, powerful elastases implicated for arterial remodeling due to chronic inflammation and disturbed blood flow.