Darbepoetin alfa protects podocytes from apoptosis in vitro and in vivo.
Detachment or apoptosis of podocytes leads to proteinuria and glomerulosclerosis. There are no current interventions for diabetic or non-diabetic glomerular diseases specifically preventing podocyte apoptosis. Binding of erythropoiesis stimulating proteins (ESPs) to receptors on non-hematopoietic cells has been shown to have anti-apoptotic effects in vitro, in vivo, and in preliminary human studies. Recently, erythropoietin receptors were identified on podocytes; therefore, we tested effects of darbepoetin alfa in preventing podocyte apoptosis. Cultured immortalized mouse podocytes were treated with low-dose ultraviolet-C (uv-C) irradiation to induce apoptosis in the absence or presence of darbepoetin alfa. Apoptosis was quantified by Hoechst staining and by caspase 3 cleavage assessed by Western blots. Pretreatment with darbepoetin alfa significantly reduced podocyte apoptosis with this effect involving intact Janus family protein kinase-2 (JAK2) and AKT signaling pathways. Additionally, darbepoetin alfa was found protective against transforming growth factor-beta1 but not puromycin aminonucleoside induced apoptosis. Mice with anti-glomerular antibody induced glomerulonephritis had significantly less proteinuria, glomerulosclerosis, and podocyte apoptosis when treated with darbepoetin alfa. Our studies show that treatment of progressive renal diseases characterized by podocyte apoptosis with ESPs may be beneficial in slowing progression of chronic kidney disease.
Logar
C M
CM
Division of Nephrology, Department of Medicine, University of Washington School of Medicine, Seattle, Washington 98195, USA. logar@u.washington.edu
Brinkkoetter
P T
PT
Krofft
R D
RD
Pippin
J W
JW
Shankland
S J
SJ
D000818:Animals; D000906:Antibodies; D017209:Apoptosis / Q000187:drug effects* / Q000528:radiation effects; D001323:Autoantibodies; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D000068256:Darbepoetin alfa; D004195:Disease Models, Animal; D018450:Disease Progression; D004921:Erythropoietin / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D005921:Glomerulonephritis / Q000150:complications / Q000276:immunology / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D005923:Glomerulosclerosis, Focal Segmental / Q000209:etiology / Q000473:pathology / Q000517:prevention & control; D053614:Janus Kinase 2 / Q000378:metabolism; D051379:Mice; D050199:Podocytes / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology / Q000528:radiation effects; D020011:Protective Agents / Q000494:pharmacology* / Q000627:therapeutic use; D011507:Proteinuria / Q000209:etiology / Q000473:pathology / Q000517:prevention & control; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D011692:Puromycin Aminonucleoside / Q000494:pharmacology; D017467:Receptors, Erythropoietin / Q000187:drug effects / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects* / Q000528:radiation effects; D053773:Transforming Growth Factor beta1 / Q000378:metabolism; D014466:Ultraviolet Rays
D000906:Antibodies; D001323:Autoantibodies; D020011:Protective Agents; D017467:Receptors, Erythropoietin; D053773:Transforming Growth Factor beta1; C051951:antiglomerular basement membrane antibody; D004921:Erythropoietin; D000068256:Darbepoetin alfa; D011692:Puromycin Aminonucleoside; C507926:Jak2 protein, mouse; D053614:Janus Kinase 2; D051057:Proto-Oncogene Proteins c-akt