Glomerular parietal epithelial cells of adult murine kidney undergo EMT to generate cells with traits of renal progenitors.
Bottom Line: When injected into E13.5 kidney rudiments, the cells incorporated into the developing kidney primordia and co-culture with E13.5 spinal cord resulted in branching and tubulogenesis in these cells.When implanted under renal capsule of unilaterally nephrectomized mice, these cells differentiated into immature glomeruli and vascular ducts.Our study demonstrates that EMT plays a major role in imparting plasticity to terminally differentiated GPECs by producing metastable cells with traits of kidney progenitors.
Affiliation: Tissue Engineering and Banking Laboratory, National Centre for Cell Science, Pune, India.Show MeSH
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Mentions: Compensatory renal growth after unilateral nephrectomy is a remarkable regenerative mechanism exhibited by the kidney. After unilateral nephrectomy, the remaining kidney increases in size, the phenomenon is known as compensatory hypertrophy . We reasoned that the mechanism of compensatory hypertrophy would provide an ideal growth and differentiation milieu for the putative kidney progenitors to exhibit renal commitment in vivo if any. FACS purified and PKH26 labelled cells (2 × 106 cells) were grafted under the left kidney capsule of normal mice (n = 5). One-week after implantation, unilateral nephrectomy of the right kidney was performed. Two weeks after nephrectomy mice were killed to visualize the status of the graft. The recovered grafts exhibited increase in size, were vascularized and no neoplasia were observed (Fig. 7A-D). Grafted CD24+ cells generated neo-glomerular, vascular and ductal structures at 3 weeks after engraftment, as determined by histological assessment of fixed sections (Fig. 7E.a-e). The cryostat sections of CD24+ graft showed that grafted cells underwent endothelial differentiation as demonstrated by the co-expression of PKH26 with PECAM in immature glomerular structures and vascular ducts (Fig. 8A). Co-expression of PKH-26 with surface localization of E-Cadherin confirmed epithelialization of the grafted cells (Fig. 8B). Flow cytometry analysis showed that 63.18 ± 5% PKH+ cells were E-Cadherin+ positive (Fig. 8C). Additional immunostaining of the grafted cells showed acquired expression of collagen 4 and laminin 1 (Fig. 9A, B) which are glomerular basement membrane components of immature nephron (comma and s-shape)  over cultured CD24+ cells. Expression of intercellular vesicle water channel protein, Aquaporin-6  and expression of mature podocyte marker nephrin was observed within the cells of the graft (Fig. 9C, D). The in vivo proliferation potential of the grafted cells was determined by Ki-67 staining (Fig. 9E). Grafting of CD24+ cells in the renal capsule of normal (un-nephrectomized) mice produced no visible differentiation within the stipulated time (data not shown).
Affiliation: Tissue Engineering and Banking Laboratory, National Centre for Cell Science, Pune, India.