Glomerular localization of erythropoietin receptor mRNA and protein in neonatal and mature mouse kidney.
OBJECTIVE
Erythropoietin (EPO) possesses well-established hematopoietic properties as the primary stimulator of red blood cell formation by binding to its receptor (EPO-R). Recent evidence suggests pathophysiological roles of EPO in several non-hematopoietic tissues including kidney. Our aim was to further clarify the glomerular localization of EPO-R in normal kidney, as well as changes in its expression during glomerulogenesis.


METHODS
We analyzed EPO-R mRNA and protein expression in neonatal and adult mouse kidney by in situ hybridization and immunohistochemistry. To confirm the precise localization and developmental changes of EPO-R expression in podocytes in mature and developing glomeruli, we examined co-expression with the podocyte markers WT-1 and synaptopodin.


RESULTS
In addition to tubular expression as reported recently, EPO-R expression was observed in podocytes as well as endocapillary cells in the glomeruli from adult mice. In newborn kidney, EPO-R mRNA and protein expression was first observed in developing podocytes in S-shaped bodies with expression subsequently increasing in glomeruli at the capillary-loop and maturing stages. Immunoelectron microscopy also demonstrated cytoplasmic expression of EPO-R that was prominent at the basal sides of podocytes in glomeruli at the late capillary-loop and maturing stage.


CONCLUSIONS
EPO-R is expressed in developing and mature podocytes in mouse kidney, suggesting a possible role for EPO in podocyte biology.
Echigoya
Masayo H
MH
Department of Pediatrics, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
Obikane
Katsuyuki
K
Nakashima
Taiji
T
Sasaki
Satoshi
S
D000818:Animals; D000831:Animals, Newborn; D020869:Gene Expression Profiling; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007678:Kidney Glomerulus / Q000201:enzymology* / Q000254:growth & development*; D051379:Mice; D016253:Microscopy, Immunoelectron; D050199:Podocytes / Q000201:enzymology*; D012333:RNA, Messenger / Q000032:analysis; D017467:Receptors, Erythropoietin / Q000032:analysis* / Q000096:biosynthesis*
D012333:RNA, Messenger; D017467:Receptors, Erythropoietin