RENIN-ANGIOTENSIN SYSTEM IN REGULATION OF HEMATOPOIESIS

The renin-angiotensin system (RAS) has long been known as the endocrine system involved in the regulation of arterial pressure and waterelectrolyte balance. Local (tissue) RAS can influence cellular activity, tissue damage and regeneration. In the bone marrow there are active ligands of peptides, mediators, receptors and signaling pathways of the RAS. Local RAS can influence the growth, production, proliferation and differentiation of hematopoietic cells and participate in the regulation of both normal and pathological hematopoiesis. Angiotensin-converting enzyme (ACE) CD143 plays a key role in the classical RAS. After differentiation from hemangioblast, hematopoietic progenitor cells constantly express ACE in human embryonic, fetal and adult hematopoietic tissues, as well as at all stages of hematopoietic ontogeny. The ACE cleaves the C-terminal dipeptide and thus forms the octapeptide Angiotensin II. In addition to angiotensin II, ACE also regulates a group of biologically active peptides, such as substance P, ac-SDKP and angiotensin 1–7. Local RAS is also one of the most important components in the tumor microenvironment, affecting tumor growth and metastasis by autocrine and paracrine pathways, modulating numerous carcinogenic events such as angiogenesis, apoptosis, cell proliferation, immune responses, and extracellular matrix formation.

The purpose of this review is to describe the known functions of local RAS in the hematopoiesis regulation. More detailed study of the RAS components mechanisms of action will expand therapy approaches in the neoplastic diseases and in bone marrow transplantation.