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Identification of wild type and variants of oestrogen receptors in polymorphonuclear and mononuclear leucocytes
Author(s) -
Stygar Denis,
Westlund Pär,
Eriksson Håkan,
Sahlin Lena
Publication year - 2006
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/j.1365-2265.2005.02420.x
Subject(s) - endocrinology , medicine , receptor , peripheral blood mononuclear cell , biology , identification (biology) , immunology , genetics , in vitro , botany
Summary Objective Leucocytes play an important role in the pathogenesis of autoimmune and cardiovascular diseases. Clinical and epidemiological observations indicate that the sex steroid hormones, particularly oestrogens, may regulate leucocyte functions. The assumption that oestrogens have a direct effect on leucocytes has to be supported by identification of functional oestrogen receptors (ER) in leucocytes. This study aimed at investigating the presence of ER subtypes in different types of leucocytes isolated from peripheral blood of female and male donors. Design and patients A total of nine men (age range 18–43 years) and nine women (age range 19–42 years) all healthy blood donors, were recruited for the study. The donors did not receive any medication or hormonal contraceptives for the last three months. Ten millilitres of peripheral blood was collected from each donor. Polymorphonuclear leucocytes (PMN) and peripheral blood mononuclear cells (PBMC) were purified by density gradient centrifugation. Measurements ERα and ERβ mRNA expression was measured by real‐time reverse transcriptase–polymerase chain reaction (RT‐PCR), and ER proteins were analysed by Western blot in the PBMC and PMN leucocyte populations. In addition, expression profiles of ER variant isoforms were characterized by conventional PCR using the splice‐targeted primer approach. Results Although we detected wild‐type ERα and ERβ mRNAs in PBMC but not in PMN cells, the ERα and ERβ proteins were found in both cell types using Western blot. We observed that both ERα and ERβ proteins differ in size between PMN and PBMC, suggesting that the two leucocyte populations contain diverse variant isoforms of ERα and ERβ. RT‐PCR analysis of exon‐deleted ER splice variants revealed that PBMC express several exon‐deleted variants of ERα and ERβ, along with wild‐type receptor, whereas the PMN cells only express exon‐deleted variant isoforms and no wild‐type ERα or ERβ. Conclusions Our study demonstrates the presence of ERα and ERβ in PBMC and PMN cells from female and male donors. The ERα and ERβ genes have complex transcriptional profiles, with many receptor variant isoforms being expressed. Considering the diversity of ER isoforms in leucocyte subtypes, we conclude that the expected effect of oestrogen would be highly cell type‐specific. Further studies are needed to test the functional activity of ER isoforms and their relation to disease.