SPP1 and aortic stenosis: Another study reported by Lorenzen et al. detected the link between increased OPN expression and activation of the transcription factor AP-1, with subsequent miR-21 induction and regulation of downstream antifibrotic targets (PTEN and SMAD7) in angiotensin 2 (ANGII/AGT)-induced cardiac cells and in LV biopsies from AS patients with myocardial fibrosis [164].