Ricerc@Sapienza

Punicalagin, a polyphenolic compound isolated from pomegranate fruit, possess several pharmacological activities including anti-inflammatory, hepatoprotective, antigenotoxic and anticoagulant activities [13]. PDIA3/ERp57, a member of the protein disulfide isomerase family, is an endoplasmatic reticulum protein mainly involved in the correct folding of newly synthetized glycoproteins. It is associated with different human diseases such as cancer, prion disorders, Alzheimer¿s and Parkinson¿s diseases [2]. PDIA3 plays an important role during platelets activation. It is secreted upon Glycoprotein VI activation and after vascular injury, extracellular PDIA3 is accumulated in the thrombus where it induces the recruitment of other platelets. It seems PDIA3 bind ß3 integrin in thrombin-activated platelets. ß3 integrins create active fibrinogen receptor (¿IIbß3) on the surface of platelets, and this needs several conformational changes that require a new pattern of disulfide bond formation [9]. The anti-PDIA3 antibody inhibits platelets aggregation and ATP secretion, calcium mobilization and activation of ¿IIbß3 in platelets stimulated by collagen-related peptide. PDIA3-null platelets reveal decreased platelets aggregation and decreased activation of ¿IIbß3 [10]. The current research is focusing on PDIA3 inhibition in platelets aggregation as a target for seeking novel anti-thrombotic agents [5a]. In this regard, our preliminary data demonstrated that punicalagin is able to bind PDIA3 with a Kd of 8,3 µM. Moreover, punicalagin can inhibit PDIA3 redox activity up to 90%. So, I would to fix the PDIA3 involvement in platelets aggregation (defining redox status of PDIA3 during ¿IIbß3 activation and PDIA3 ability to induce ß3 activation) and test punicalagin as a possible PDIA3 inhibitor (determining Kd by ITC, Km by kinetic assay, its relative affinity to PDIA3 respect other PDIs and capability to inhibit platelets aggregation).