Bioaktivu mazmolekularo NO-induktoru un donoru sinteze un izpete

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Protein disulfide isomerase-A1 regulates intraplatelet reactive oxygen speciesthromboxane A<SUB>2</SUB>-dependent pathway in human platelets

BACKGROUND: Platelet‐derived protein disulfide isomerase 1 (PDIA1) regulates thrombus formation, but its role in the regulation of platelet function is not fully understood. AIMS: The aim of this study was to characterize the role of PDIA1 in human platelets. METHODS: Proteomic analysis of PDI isoforms in platelets was performed using liquid chromatography tandem mass spectometry, and the expression of PDIs on platelets in response to collagen, TRAP‐14, or ADP was measured with flow cytometry. The effects of bepristat, a selective PDIA1 inhibitor, on platelet aggregation, expression of platelet surface activation markers, thromboxane A(2) (TxA(2)), and reactive oxygen species (ROS) generation were evaluated by optical aggregometry, flow cytometry, ELISA, and dihydrodichlorofluorescein diacetate‐based fluorescent assay, respectively. RESULTS: PDIA1 was less abundant compared with PDIA3 in resting platelets and platelets stimulated with TRAP‐14, collagen, or ADP. Collagen, but not ADP, induced a significant increase in PDIA1 expression. Bepristat potently inhibited the aggregation of washed platelets induced by collagen or convulxin, but only weakly inhibited platelet aggregation induced by TRAP‐14 or thrombin, and had the negligible effect on platelet aggregation induced by arachidonic acid. Inhibition of PDIA1 by bepristat resulted in the reduction of TxA(2) and ROS production in collagen‐ or thrombin‐stimulated platelets. Furthermore, bepristat reduced the activation of αIIbβ3 integrin and expression of P‐selectin. CONCLUSIONS: PDIA1 acts as an intraplatelet regulator of the ROS‐TxA(2) pathway in collagen‐GP VI receptor‐mediated platelet activation that is a mechanistically distinct pathway from extracellular regulation of αIIbβ3 integrin by PDIA3

Aziridine-2-carboxylic acid derivatives and its open-ring isomers as a novel PDIA1 inhibitors

Acyl derivatives of aziridine-2-carboxylic acid have been synthesized and tested as PDIA1 inhibitors. Calculations of charge value and distribution in aziridine ring system and some alkylating agents were performed. For the first time was found that acyl derivatives of aziridine-2-carboxylic acid are weak to moderately active PDIA1 inhibitors

Comparison of anti-cancer effects of novel protein disulphide isomerase (PDI) inhibitors in breast cancer cells characterized by high and low PDIA17 expression

Protein disulphide isomerases (PDIs) play an important role in cancer progression. However, the relative contribution of the various isoforms of PDI in tumorigenesis is not clear

Protein disulfide isomerase A1 regulates fenestration dynamics in primary mouse liver sinusoidal endothelial cells (LSECs)

Protein disulfide isomerases (PDIs) are involved in many intracellular and extracellular processes, including cell adhesion and cytoskeletal reorganisation, but their contribution to the regulation of fenestrations in liver sinusoidal endothelial cells (LSECs) remains unknown. Given that fenestrations are supported on a cytoskeleton scaffold, this study aimed to investigate whether endothelial PDIs regulate fenestration dynamics in primary mouse LSECs.PDIA3 and PDIA1 were found to be the most abundant among PDI isoforms in LSECs. Taking advantage of atomic force microscopy, the effects of PDIA1 or PDIA3 inhibition on the fenestrations in LSECs were investigated using a classic PDIA1 inhibitor (bepristat) and novel aromatic N-sulfonamides of aziridine-2-carboxylic acid derivatives as PDIA1 (C-3389) or PDIA3 (C-3399) inhibitors. The effect of PDIA1 inhibition on liver perfusion was studied in vivo using dynamic contrast-enhanced magnetic resonance imaging. Additionally, PDIA1 inhibitors were examined in vitro in LSECs for effects on adhesion, cytoskeleton organisation, bioenergetics, and viability.Inhibition of PDIA1 with bepristat or C-3389 significantly reduced the number of fenestrations in LSECs, while inhibition of PDIA3 with C-3399 had no effect. Moreover, the blocking of free thiols by the cell-penetrating N-ethylmaleimide, but not by the non-cell-penetrating 4-chloromercuribenzenesulfonate, resulted in LSEC defenestration. Inhibition of PDIA1 did not affect LSEC adhesion, viability, and bioenergetics, nor did it induce a clear-cut rearrangement of the cytoskeleton. However, PDIA1-dependent defenestration was reversed by cytochalasin B, a known fenestration stimulator, pointing to the preserved ability of LSECs to form new pores. Importantly, systemic inhibition of PDIA1 in vivo affected intra-parenchymal uptake of contrast agent in mice consistent with LSEC defenestration.These results revealed the role of intracellular PDIA1 in the regulation of fenestration dynamics in LSECs, and in maintaining hepatic sinusoid homeostasis