CURRENT APPROACHES TO THE IDENTIFICATION OF CELLULAR MARKERS OF ENDOTHELIAL DYSFUNCTION

Highlights Potential cellular markers of vasospastic endothelial dysfunction include endothelial NO synthase and its phosphorylated forms, mechanosensitive transcription factors, as well as markers of nitrosative and oxidative stress. Probable cellular markers of proinflammatory endothelial dysfunction may encompass transcription factors of the endothelial-mesenchymal transition, proinflammatory transcription factors, mechanosensitive transcription factors, inducible cell adhesion molecules, components of the basement membrane, and key endothelial integrins. Cellular markers of prothrombotic endothelial dysfunction may include components of the endothelial glycocalyx, as well as membrane and cytoplasmic anti- and prothrombotic molecules responsible for regulating local and systemic hemostasis. Abstract This review examines several groups of potential cellular markers for various types of endothelial dysfunction: vasospastic, proinflammatory, and prothrombotic. For this purpose, we screened the PubMed database for the respective publications over the past 45 years. Immunohistochemical analysis of the development of vasospastic endothelial dysfunction involves measuring the expression of endothelial NO synthase and its phosphorylated forms (serine-113/117, threonine-495, serine-632, serine-1176/1177), mechanosensitive transcription factors (KLF2, KLF4, and NRF2), markers of nitrosative stress (3-nitrotyrosine and 6-nitrotryptophan), and oxidative stress markers (proteins associated with malondialdehyde or methylglyoxal, xanthine oxidase, and isoforms of NADPH oxidase NOX1, NOX2, NOX4, and NOX5). Potential immunohistochemical markers of proinflammatory endothelial dysfunction include N-cadherin as a mesenchymal cell marker in combination with the loss of endothelial markers (CD31 and VE-cadherin), transcription factors of endothelial-mesenchymal transition (Snail, Slug, Twist1, and Zeb1), proinflammatory transcription factors (NF-κB, IRF1, IRF3, IRF5, IRF7, AP-1, ATF1, ATF2, ATF3, ATF4, ATF6, EGR-1, EGR-3, STAT1, STAT3, and STAT4), NLRP3 as a marker of inflammasomes, the aforementioned mechanosensitive transcription factors, inducible cell adhesion molecules (VCAM1, ICAM1, E-selectin), as well as components of the basement membrane (laminin, type IV collagen, nidogen-1, nidogen-2, perlecan, fibronectin) and endothelial integrins (α2β1, α3β1, α5β1, α9β1, αvβ3, αvβ5). Immunohistochemical analysis of prothrombotic endothelial dysfunction may rely on assessing the expression of components of the endothelial glycocalyx (via immunofluorescent staining with UEA-1, which binds to fucosylated glycans, or through immunohistochemical staining for syndecan-1, heparan sulfate, chondroitin sulfate, hyaluronic acid, perlecan, and glypican-1), as well as evaluating the expression of its antithrombotic (antithrombin III, tissue factor inhibitor, thrombomodulin, CD39, CD73) or prothrombotic proteins (heparanase, hyaluronidase, angiotensin-converting enzyme 2, von Willebrand factor). Verification of immunohistochemical markers differentially expressed in control and model animals should be conducted using electron microscopy of adjacent vascular segments to establish associative and correlative relationships between molecular and pathomorphological markers.