Glucocorticoids regulate thrombopoiesis by remodeling the megakaryocyte transcriptome

J Thromb Haemost. 2023 Nov;21(11):3207-3223. doi: 10.1016/j.jtha.2023.06.012. Epub 2023 Jun 17.

Abstract

Background: Glucocorticoids are widely known for their immunomodulatory action. Their synthetic analogs are used to treat several autoimmune diseases, including immune thrombocytopenia. However, their efficacy and mechanisms of action in immune thrombocytopenia are not fully understood.

Objectives: To investigate the mechanism of glucocorticoid actions on platelet production.

Methods: The actions of glucocorticoids on platelet production were studied combining in vivo, ex vivo and in vitro approaches.

Results: Dexamethasone reduced bleeding in mice and rapidly increased circulating young platelet counts. In vitro glucocorticoid treatment stimulated proplatelet formation by megakaryocytes and platelet-like particle release. This effect was blocked by glucocorticoid receptor antagonist RU486, indicating a glucocorticoid receptor-dependent mechanism. Genome-wide analysis revealed that dexamethasone regulates the expression of >1000 genes related to numerous cellular functions, including predominant cytoplasm and cytoskeleton reorganization. Dexamethasone and other glucocorticoids induced the expression of Gda (the gene encoding guanine deaminase), which has been reported to have a role in dendrite development. Inhibition of guanine deaminase enzymatic activity blocked dexamethasone stimulation of proplatelet formation, implicating a critical role for this enzyme in glucocorticoid-mediated platelet production.

Conclusion: Our findings identify glucocorticoids as new regulators of thrombopoiesis.

Keywords: glucocorticoid receptors; glucocorticoids; megakaryocytes; thrombopoiesis; transcriptome.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Animals
  • Blood Platelets / metabolism
  • Dexamethasone / pharmacology
  • Glucocorticoids / pharmacology
  • Guanine Deaminase* / metabolism
  • Megakaryocytes / metabolism
  • Mice
  • Purpura, Thrombocytopenic, Idiopathic*
  • Receptors, Glucocorticoid / genetics
  • Receptors, Glucocorticoid / metabolism
  • Thrombocytopenia* / metabolism
  • Thrombopoiesis / physiology
  • Transcriptome

Substances

  • Glucocorticoids
  • Receptors, Glucocorticoid
  • Guanine Deaminase
  • Dexamethasone