Promegakaryocyte

{{Short description|Precursor cell to a megakaryocyte}}

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Image:Promegakaryocyte.png

A promegakaryocyte is a precursor cell for a megakaryocyte, the development of which proceeds as follows:{{Cite book| vauthors = Betts JG, Desaix P, Johnson E, Johnson JE, Korol O, Kruse D, Poe B |url=https://www.worldcat.org/oclc/898069394|title=Anatomy & Physiology|date=2013 |isbn=978-1-947172-04-3|location=Houston, Texas | publisher = OpenStax College, Rice University |oclc=898069394}}

:CFU-Meg (hematopoietic stem cell/hemocytoblast) → megakaryoblast → promegakaryocyte → megakaryocyte

Promegakaryocytes and other precursor cells to megakaryocytes arise from pluripotential hematopoietic progenitors,{{Cite book|url=https://www.worldcat.org/oclc/162572838|title=Platelets|date=2007|publisher=Academic Press/Elsevier| vauthors = Michelson AD |isbn=978-0-12-369367-9|edition=2nd |location=Amsterdam|oclc=162572838}} also known as hemocytoblasts. The megakaryoblast is then produced, followed by the promegakaryocyte, the granular megakaryocyte, and then the mature megakaryocyte.{{Citation| vauthors = Stiff PJ |title= Platelets |date=1990 |url=http://www.ncbi.nlm.nih.gov/books/NBK262/|work=Clinical Methods: The History, Physical, and Laboratory Examinations| veditors = Walker HK, Hall WD, Hurst JW |edition=3rd|place=Boston|publisher=Butterworths|isbn=978-0-409-90077-4|pmid=21250105|access-date=2021-10-13}} When it is in its promegakaryocyte stage, it is considered an undifferentiated cell.{{cite journal | vauthors = Lee YS, Kwak MK, Moon SA, Choi YJ, Baek JE, Park SY, Kim BJ, Lee SH, Koh JM | title = Regulation of bone metabolism by megakaryocytes in a paracrine manner | journal = Scientific Reports | volume = 10 | issue = 1 | pages = 2277 | date = February 2020 | pmid = 32042021 | pmc = 7010738 | doi = 10.1038/s41598-020-59250-6 | bibcode = 2020NatSR..10.2277L }}

When the megakaryoblast matures into the promegakaryocyte, it undergoes endoreduplication{{cite book | vauthors = Khurana I |date=November 20, 2009 |title=Textbook of Human Physiology for Dental Students |publisher=Elsevier India |page=141 |isbn=978-8131205921 }} and forms a promegakaryocyte which has multiple nuclei, azurophilic granules, and a basophilic cytoplasm.{{cite book | vauthors = Rozenberg G |date=December 19, 2002 |title=Microscopic Haematology: A Practical Guide for the Laboratory |publisher=CRC Press |page=95 |isbn=1841842338 |edition=2nd }} The promegakaryocyte has rotary motion, but no forward migration.{{cite journal | vauthors = Hiraki K, Ofuji T, Kobayashi T, Sunami H, Awai K |date=January 31, 1956 |title=On the function of the Megakaryocyte (Motility, Separation of the Platelet and Phagocytosis), Observations Both in Idiopathic Thrombocytopenic Purpura and in Normal Adult |url=http://ousar.lib.okayama-u.ac.jp/en/30294 |journal=Acta Medicinae Okayama |volume=10 |issue=2 |pages=57–61 |access-date=July 21, 2017 }}

Megakaryocyte pieces will eventually break off and begin circulating the body as platelets. Platelets are very important because of their role in blood clotting, immune response, and the formation of new blood vessels.{{cite journal | vauthors = Wilcox DA | title = Megakaryocyte- and megakaryocyte precursor-related gene therapies | journal = Blood | volume = 127 | issue = 10 | pages = 1260–1268 | date = March 2016 | pmid = 26787735 | pmc = 4786835 | doi = 10.1182/blood-2015-07-607937 }}