Application of Porcine Kidney-Derived Extracellular Matrix as Coating, Hydrogel, and Scaffold Material for Renal Proximal Tubular Epithelial Cell

BACKGROUND: Human renal proximal tubular epithelial (RPTE) cell is a very useful tool for kidney-related experiments in vitro/ex vivo. However, only a few primary RPTE cells can be obtained through kidney biopsy, the proliferation rate of primary cell is very low, and the cultured cell properties are easily altered in artificial conditions. Thus, RPTE cell usage is very tricky; we applied porcine kidney-derived extracellular matrix (renal ECM) as coating, hydrogel, and scaffold material to increase cell proliferation and maintain cellular properties providing three-dimensional (3D) niche, which can be a valuable cell delivery vehicle. METHODS: Porcine renal ECM was prepared by decellularization using 1% Triton X-100, solubilized with 0.5 M acetic acid. The final protein concentration was adjusted to 10 μg/μL (pH 7.0). The efficacies as coating, hydrogel, and scaffold materials were analyzed through cell morphology, proliferation rate, renal-associated gene expressions, chemical composition, and microstructure evaluation. The efficacies as a coating material were compared with Matrigel, collagen type 1 (col1), gelatin, fibrinogen, and thrombin. After confirmation of coating effects, the effective concentration range was decided. The efficacies as hydrogel and scaffold materials were compared with hyaluronic acid (HA) and col1, respectively. RESULTS: As the coating material, renal ECM showed a higher cell proliferation rate compared to other materials, except for Matrigel. Renal-associated gene expressions were significantly enhanced in the renal ECM than other materials. Coating effect on cell proliferation was dependent on the renal ECM concentration, and the effective concentration ranged from 30 to 100 μg. As the hydrogel material, renal ECM showed a distinct inner cell network morphology and significantly increased renal-associated gene expressions, compared to HA hydrogel. As the scaffold material, renal ECM showed specific amide peaks, enhanced internal porosity, cell proliferation rate, and renal-associated gene expression compared to the col1 scaffold. CONCLUSIONS: We concluded that renal ECM can be a suitable material for RPTE cell culture and usage. More practically, the coated renal ECM stimulates RPTE cell proliferation, and the hydrogel and scaffold of renal ECM provide useful 3D culture niche and cell delivery vehicles maintaining renal cell properties.