Expression of transient receptor potential mRNA isoforms and Ca(2+) influx in differentiating human stem cells and platelets.

E. den Dekker, D.G.M. Molin, G. Breikers, R. van Oerle, J.W.N. Akkerman, G.J.J.M. van Eys, J.W.M. Heemskerk

Research output: Contribution to journalArticleAcademicpeer-review

63 Citations (Scopus)

Abstract

Biochim Biophys Acta 2001 Jun 20;1539(3):243-55 Related Articles, Books, LinkOut


Expression of transient receptor potential mRNA isoforms and Ca(2+) influx in differentiating human stem cells and platelets.

den Dekker E, Molin DG, Breikers G, van Oerle R, Akkerman JW, van Eys GJ, Heemskerk JW.

Laboratory for Thrombosis and Haemostasis, Department of Haematology, University Medical Centre Utrecht, The Netherlands.

Store-regulated Ca(2+) entry (SOCE) is an important mechanism of elevating cytosolic [Ca(2+)]i in platelets, though the Ca(2+) influx channels involved are still unclear. We screened human platelets and their precursor cells (human stem cells and megakaryocytes) for the presence of candidate influx channels, i.e., isoforms of the Trp family of proteins. Primary stem cells were cultured with thrombopoietin to allow differentiation into megakaryocytes. The undifferentiated stem cells (CD34(+)) showed mRNA expression of only a spliced variant Trp1A. Immature (CD61(+)/CD42b(low)) and mature (CD61(+)/CD42b(high)) megakaryocytes as well as platelets expressed in addition unspliced Trp1 as well as Trp4 (less abundant) and Trp6 isoforms. This unspliced isoform appeared to be specific for cells of the megakaryocyte/platelet lineage, since immature (CD14(+)/CD61(-)/CD42b(-)) and mature monocytes expressed only the Trp1A isoform. This conclusion was confirmed by the presence of Trp1A, 3, 4 and 6 transcripts in the immature megakaryocytic Dami cell line, and of Trp1, 1A, 4 and 6 transcripts in the more mature CHRF-288 cell line. The up-regulation of Trp1, 4 and 6 in the lineage from primary stem cells to mature megakaryocytes and platelets was accompanied by increased influx of extracellular Ca(2+) after pretreatment of the cells with thapsigargin or thrombin. Expression of new Trp isoforms in the differentiated cells is thus accompanied by increased SOCE.

Original languageEnglish
Pages (from-to)243-255
Number of pages13
JournalBiochimica et Biophysica Acta. Mucoproteins and Mucopolysaccharides
Volume1539
DOIs
Publication statusPublished - 1 Jan 2001

Cite this