Cyclic stretch is an important inducer of vascular smooth muscle cell (VSMC) proliferation, which is crucial in vascular remodeling during hypertension. However, the molecular mechanism remains unclear. We studied the effects of emerin and lamin A/C, two important nuclear envelope proteins, on VSMC proliferation in hypertension and the underlying mechano-mechanisms. In common carotid artery of hypertensive rats in vivo and in cultured cells subjected to high (15%) cyclic stretch in vitro, VSMC proliferation was increased significantly, and the expression of emerin and lamin A/C was repressed compared with normotensive or normal (5%) cyclic stretch controls. Using targeted siRNA to mimic the repressed expression of emerin or lamin A/C induced by 15% stretch, we found that VSMC proliferation was enhanced under static and 5%-stretch conditions. Overexpression of emerin or lamin A/C reversed VSMC proliferation induced by 15% stretch. Hence, emerin and lamin A/C play critical roles in suppressing VSMC hyperproliferation induced by hyperstretch. ChIP-on-chip and MOTIF analyses showed that the DNAs binding with emerin contain three transcription factor motifs: CCNGGA, CCMGCC, and ABTTCCG; DNAs binding with lamin A/C contain the motifs CVGGAA, GCCGCYGC, and DAAGAAA. Protein/DNA array proved that altered emerin or lamin A/C expression modulated the activation of various transcription factors. Furthermore, accelerating local expression of emerin or lamin A/C reversed cell proliferation in the carotid artery of hypertensive rats in vivo. Our findings establish the pathogenetic role of emerin and lamin A/C repression in stretch-induced VSMC proliferation and suggest mechanobiological mechanism underlying this process that involves the sequencespecific binding of emerin and lamin A/C to specific transcription factor motifs.T he cyclic stretch caused by the rhythmical distention and relaxation of the arterial wall during the cardiac cycle is an important factor in the regulation of vascular modeling and remodeling (1, 2). There is growing evidence that mechanical cyclic stretch modulates the functions (e.g., apoptosis, proliferation, and migration) of vascular smooth muscle cells (VSMCs) in the media of the arterial wall (2) and that chronically elevated cyclic stretch stimulates VSMC functions to mediate vascular remodeling during hypertension (3, 4).It has been shown that there are various mechano-sensors in the vascular cell membrane, including lipids (5), glycocalyx (6), and proteins such as integrins (7), G proteins and G protein-coupled receptors (8), receptor tyrosine kinase (9), and Ca 2+ channel (10) and intercellular junction proteins (2, 11). In recent years, it has been suggested that nuclear envelope (NE) proteins, a hallmark of eukaryotic cells, participate in the mechano-transduction networks. Our previous proteomic analysis revealed that lamin A/C, one kind of NE protein, is mechano-responsive and may contribute to the shear stress-induced proliferation and migration of VSMCs (12). Recently, Swift et al. (13) ...