However, a recent study using SMC-specific TGFBR2-deficient mice demonstrated that a loss of smooth muscle TGF-β signaling, when combined with hyperlipidemia, stimulates the transdifferentiation of media SMC to a mesenchymal stem cell–like (MSC-like) state and promotes aortic aneurysm (21). The gene discussed is TGFB1; the disease is aortic aneurysm.