Human fetal kidney cells regenerate acellular porcine kidneys via upregulation of key transcription factors involved in kidney development<em>Running title: Regeneration of porcine kidneys</em>

Abstract

Interaction between organ-specific stem cells and extracellular matrix (ECM) is crucial for regeneration. We therefore, investigated novel stem cells markers in human kidney and verified the potential of human fetal kidney cells (hFKC) to repopulate decellularized porcine kidneys. Adult and fetal human kidneys were stained by immunohistochemistry for putative stem cell markers. In addition, hFKC were isolated and characterized phenotypically and by gene expression. Furthermore, whole porcine kidneys were decellularized using detergents, cut into 1 mm slices, seeded with hFKC, cultured for 14 days and characterized by histology and qPCR. We found that, decellularized porcine kidneys showed significant loss of DNA but preserved some ECM components. Human fetal kidneys including hFKC expressed stem cell markers CD133, DLK-1, EPCAM and ephrin receptor EphA6. Interestingly, EphA7 and SIX2 were markedly expressed only in fetus. Furthermore, in fetal kidneys EphA7 was co-expressed with DLK-1. Recellularized kidney pieces showed cell infiltration, growing in orchestrated fashion distributed around the scaffold. These pieces also demonstrated cells expressing CK8, CK18, DLK-1, CD133, EphA7, EphB3, PCNA, podocin and increased levels of transcriptional factors in kidney development (SIX2, EYA1, CITED1, LHX1, SALL1, DLK-1 and WT1). We conclude that decellularized porcine kidneys support the culture, proliferation of hFKC and regenerate by upregulation of transcription factors. We suggest that expanded hFKC may be the ideal cell source for whole kidney regeneration in the future. We also postulate EphA7 might be a novel stem cell marker in kidneys.