Research Mentor Name
Research Mentor Email Address
Institution / Department
University of California San Diego Department of Medicine
Level of Research
The Kruppel-like Factors 2 and 4 (KLF2/4) are transcription factors and master regulators of endothelial cells (ECs) phenotype and homeostasis. KLF2/4 are important blood-flow-responsive genes within ECs that differentially regulate the expression of factors that confer anti-inflammatory, antithrombotic, and antiproliferative effects in ECs. We found that genetic inactivation of endothelial Krit1 (Krev interaction trapped protein 1) or Heg1 (Heart of glass) led to upregulation of KLF2/4 expression levels. We also observed that vasoprotective proteins, endothelial nitric oxide synthase (eNOS) and thrombomodulin (TM), are upregulated by the increase of KLF2/4 as a result of loss of endothelial KRIT1. Here, we developed a high-throughput screening assay to identify inhibitors of the HEG1-KRIT1 interaction and identified sirtinol (HKi001) as a promising hit inhibitor. The crystal structure of sirtinol bound to the KRIT1 FERM domain confirmed the primary screening results and ultimately led to the identification of a fragment-like inhibitor (HKi002), which occupies the HEG1 pocket producing comparable activity. These findings suggest that these inhibitors block the interaction by competing with the HEG1 for binding to KRIT1 FERM domain. Moreover, our results demonstrate that HKi002 upregulates KLF2/4 gene expression in two types of human ECs. These results reveal an unexpected role of inhibiting the HEG1-KRIT1 interaction and provide a proof-of-concept that pharmacological manipulation of this complex may offer new opportunities to induce expression of KLF2/4 as vasoprotective factors.
Medicine and Health Sciences
Lopez-Ramirez, Miguel; Li, Wenqing; Haynes, Mark; Hale, Preston; McCurdy, Sara; Francisco, Karol; Oukoloff, Killian; Bautista, Matthew H.; Choi, Chelsea; Sun, Hao; Gongol, Brendan; Shyy, John; Ballatore, Carlo; Sklar, Larry; and Gingras, Alexandre, "Inhibition of the HEG1-KRIT1 interaction increases KLF4 and KLF2 expression in endothelial cells" (2021). Medical Student Research Symposium. 87.