{"title":"Potential and limitations of PKA/ PKG inhibitors for platelet studies.","authors":"Valentina Shpakova, Natalia Rukoyatkina, Ulrich Walter, Stepan Gambaryan","doi":"10.1080/09537104.2021.2003316","DOIUrl":null,"url":null,"abstract":"<p><p>Cyclic nucleotides (cAMP and cGMP) and corresponding protein kinases, protein kinase A (PKA) and protein kinase G (PKG), are the main intracellular mediators of endothelium-derived platelet inhibitors. Pharmacological PKA/PKG inhibitors are often used to discriminate between these two kinase activities and to analyze their underlying mechanisms. Previously we showed that all widely used PKG inhibitors (KT5823, DT3, RP isomers) either did not inhibit PKG or inhibited and even activated platelets independently from PKG. In this study, we examined several PKA inhibitors as well as inhibitors of adenylate and guanylate cyclases to reveal their effects on platelets and establish whether they are mediated by PKA/PKG. The commonly used PKA inhibitor H89 inhibited both PKA and PKG but PKA-independently inhibited thrombin-induced platelet activation. In our experiments, KT5720 did not inhibit PKA and had no effect on platelet activation. PKI inhibited PKA activity in platelets but also strongly PKA-independently activated platelets. Inhibition of adenylate and guanylate cyclases may be an alternative approach to analyze PKA/PKG function. Based on our previous and presented data, we conclude that all results where the mentioned PKA inhibitors were used for the analysis of PKA activity in intact platelets should be considered with caution.</p>","PeriodicalId":20268,"journal":{"name":"Platelets","volume":null,"pages":null},"PeriodicalIF":2.5000,"publicationDate":"2022-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"1","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Platelets","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1080/09537104.2021.2003316","RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2021/11/30 0:00:00","PubModel":"Epub","JCR":"Q3","JCRName":"CELL BIOLOGY","Score":null,"Total":0}
引用次数: 1
Abstract
Cyclic nucleotides (cAMP and cGMP) and corresponding protein kinases, protein kinase A (PKA) and protein kinase G (PKG), are the main intracellular mediators of endothelium-derived platelet inhibitors. Pharmacological PKA/PKG inhibitors are often used to discriminate between these two kinase activities and to analyze their underlying mechanisms. Previously we showed that all widely used PKG inhibitors (KT5823, DT3, RP isomers) either did not inhibit PKG or inhibited and even activated platelets independently from PKG. In this study, we examined several PKA inhibitors as well as inhibitors of adenylate and guanylate cyclases to reveal their effects on platelets and establish whether they are mediated by PKA/PKG. The commonly used PKA inhibitor H89 inhibited both PKA and PKG but PKA-independently inhibited thrombin-induced platelet activation. In our experiments, KT5720 did not inhibit PKA and had no effect on platelet activation. PKI inhibited PKA activity in platelets but also strongly PKA-independently activated platelets. Inhibition of adenylate and guanylate cyclases may be an alternative approach to analyze PKA/PKG function. Based on our previous and presented data, we conclude that all results where the mentioned PKA inhibitors were used for the analysis of PKA activity in intact platelets should be considered with caution.
期刊介绍:
Platelets is an international, peer-reviewed journal covering all aspects of platelet- and megakaryocyte-related research.
Platelets provides the opportunity for contributors and readers across scientific disciplines to engage with new information about blood platelets. The journal’s Methods section aims to improve standardization between laboratories and to help researchers replicate difficult methods.
Research areas include:
Platelet function
Biochemistry
Signal transduction
Pharmacology and therapeutics
Interaction with other cells in the blood vessel wall
The contribution of platelets and platelet-derived products to health and disease
The journal publishes original articles, fast-track articles, review articles, systematic reviews, methods papers, short communications, case reports, opinion articles, commentaries, gene of the issue, and letters to the editor.
Platelets operates a single-blind peer review policy. Authors can choose to publish gold open access in this journal.