Professor Vanderbilt University Nasvhille, Tennessee, United States
Introduction: Calcific aortic valve disease (CAVD) affects 25% of those over 65 in the United States alone; however, no therapies exist due to the issue that the molecular mechanism of CAVD is poorly understood. The disease is believed to be primarily driven by the valve interstitial cells (VICs), which are fibroblast-like cells that are found within the three layers of the aortic valve. In the beginning stages of the disease, VICs are activated and express cadherin-11 (CDH11), a homotypic cadherin that interacts through strong binding that can lead to excessive inter-cellular tension, resulting in tearing of the cell membrane and apoptosis and calcification. In the genetic model of CAVD, Notch1+/- mice, targeting CDH11 genetically or pharmacologically prevents development of CAVD, including the clinical hallmark, aortic stenosis (AS). Our lab has previously demonstrated that targeting CDH11 with a mAb can prevent CAVD associated with mutations of Notch1 in vivo. However, the delivery method for targeting CDH11 with a mAb is not ideal for patients with mild AS. We thus hypothesize that a novel, soluable small molecule CDH11 binding compound can prevent progression of CAVD.
Materials and
Methods: Based on the binding domain found within CDH11 that allows it to engage in homotypic interactions as well as previous studies showing that dimethyl celecoxib (DMC) is able to reduce CDH11 expression due to interacting with the same domain, a sulfoximine compound (SMC) was designed based on the structure of DMC with the intention of binding to CDH11. A calcific nodule assay was used as an in vitro method to determine how well SMC binds to CDH11 and inhibit its activity. VICs were plated onto pronectin Flexcell plates, treated with SMC or vehicle and transforming growth factor β1 (TGF-β1), and biaxially strained at 10% using the Flexcell Tension system. Alizarin Red was used to stain and detect the calcified nodules found within the wells.
Results, Conclusions, and Discussions: Compared to TGF-β1 only treated conditions, fewer calcific nodules are seen in wells treated with SMC. Additionally, the number of nodules seen in SMC treated wells are comparable to DMC treated conditions. Based on these results and previous understanding of DMC binding, SMC is speculated to bind to CDH11 in a similar manner and also inhibit progression leading to calcification. Successfully targeting of CDH11 with SMC results in reduced expression of CDH11 and subsequently prevents progression of CAVD. Future experiments will use an in vitro method of a Fc antibody covalently linked to tissue culture plastic to triage novel SMC analogs that inhibit CDH11 binding with cultured VICs.
