Genetic podocyte lineage reveals progressive podocytopenia with parietal cell hyperplasia in a murine model of cellular/collapsing focal segmental glomerulosclerosis.
Focal segmental glomerulosclerosis (FSGS) is a progressive renal disease, and the glomerular visceral cell hyperplasia typically observed in cellular/collapsing FSGS is an important pathological factor in disease progression. However, the cellular features that promote FSGS currently remain obscure. To determine both the origin and phenotypic alterations in hyperplastic cells in cellular/collapsing FSGS, the present study used a previously described FSGS model in p21-deficient mice with visceral cell hyperplasia and identified the podocyte lineage by genetic tagging. The p21-deficient mice with nephropathy showed significantly higher urinary protein levels, extracapillary hyperplastic indices on day 5, and glomerular sclerosis indices on day 14 than wild-type controls. X-gal staining and immunohistochemistry for podocyte and parietal epithelial cell (PEC) markers revealed progressive podocytopenia with capillary collapse accompanied by PEC hyperplasia leading to FSGS. In our investigation, non-tagged cells expressed neither WT1 nor nestin. Ki-67, a proliferation marker, was rarely associated with podocytes but was expressed at high levels in PECs. Both terminal deoxynucleotidyl transferase dUTP nick-end labeling staining and electron microscopy failed to show evidence of significant podocyte apoptosis on days 5 and 14. These findings suggest that extensive podocyte loss and simultaneous PEC hyperplasia is an actual pathology that may contribute to the progression of cellular/collapsing FSGS in this mouse model. Additionally, this is the first study to demonstrate the regulatory role of p21 in the PEC cell cycle.
Department of Pathology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan.
Taisei
T
Suzuki
Taiji
T
Matsusaka
Makiko
M
Nakayama
Takako
T
Asano
Teruo
T
Watanabe
Iekuni
I
Ichikawa
Michio
M
Nagata
D000818:Animals; D017209:Apoptosis / Q000502:physiology; D019070:Cell Lineage; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000502:physiology; D004195:Disease Models, Animal; D005919:Glomerular Filtration Rate; D005923:Glomerulosclerosis, Focal Segmental / Q000378:metabolism / Q000473:pathology*; D006965:Hyperplasia; D020287:In Situ Nick-End Labeling; D019426:Integrases; D019394:Ki-67 Antigen / Q000378:metabolism; D007678:Kidney Glomerulus / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008565:Membrane Proteins / Q000502:physiology; D051379:Mice; D018345:Mice, Knockout; D050199:Podocytes / Q000378:metabolism / Q000473:pathology*; D011507:Proteinuria / Q000209:etiology / Q000473:pathology; D025721:WT1 Proteins / Q000378:metabolism
C493957:Cdkn1a protein, mouse; D050759:Cyclin-Dependent Kinase Inhibitor p21; D019394:Ki-67 Antigen; D008565:Membrane Proteins; D025721:WT1 Proteins; C113267:nephrin; C045073:Cre recombinase; D019426:Integrases