Engineered extracellular matrices with controlled mechanics modulate renal proximal tubular cell epithelialization

• Published in: PloS one Vol. 12; no. 7; p. e0181085
• Main Authors: Beamish, Jeffrey A, Chen, Evan, Putnam, Andrew J
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 17-07-2017; Public Library of Science (PLoS)
• Subjects: Activation; Acute kidney failure; Adaptor Proteins, Signal Transducing - metabolism; Adhesion; Apoptosis; Apoptosis - drug effects; Biology and Life Sciences; Biomedical engineering; Care and treatment; Cell culture; Cell growth; Cell Nucleus - metabolism; Cell Polarity; Cell proliferation; Cell Proliferation - drug effects; Cells, Cultured; Collagen; Collagen Type IV - chemistry; Collagen Type IV - metabolism; Cytoskeleton; Cytoskeleton - drug effects; Epithelial cells; Epithelial Cells - cytology; Epithelial Cells - metabolism; Epithelium; Extracellular matrix; Extracellular signal-regulated kinase; Extracellular Signal-Regulated MAP Kinases - antagonists & inhibitors; Extracellular Signal-Regulated MAP Kinases - metabolism; Flavonoids - pharmacology; Focal adhesion kinase; Focal Adhesion Protein-Tyrosine Kinases - metabolism; Focal Adhesions - drug effects; Genetic aspects; Growth factors; Humans; Hydrogel, Polyethylene Glycol Dimethacrylate - chemistry; Hydrogel, Polyethylene Glycol Dimethacrylate - pharmacology; Hydrogels; Kidney Tubules, Proximal - cytology; Kidneys; Kinases; Localization; Mechanical properties; Mechanics; Mechanics (physics); Microscopy, Fluorescence; Morbidity; Nephrology; Patient outcomes; Phosphoproteins - metabolism; Phosphorylation; Physical Sciences; Physiological aspects; Polarity; Polyethylene glycol; Recovery; Research and analysis methods; Signal transduction; Stiffness; Stress, Mechanical; Substrate inhibition; Tight Junctions; Transcription Factors; Vinculin - metabolism; YAP-Signaling Proteins; Yes-associated protein; United States; Ann Arbor Michigan; United States > US; Michigan
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0181085

Acute kidney injury (AKI) is common and associated with significant morbidity and mortality. Recovery from many forms of AKI involves the proliferation of renal proximal tubular epithelial cells (RPTECs), but the influence of the microenvironment in which this recovery occurs remains poorly understood. Here we report the development of a poly(ethylene glycol) (PEG) hydrogel platform to study the influence of substrate mechanical properties on the proliferation of human RPTECs as a model for recovery from AKI. PEG diacrylate based hydrogels were generated with orthogonal control of mechanics and cell-substrate interactions. Using this platform, we found that increased substrate stiffness promotes RPTEC spreading and proliferation. RPTECs showed similar degrees of apoptosis and Yes-associated protein (YAP) nuclear localization regardless of stiffness, suggesting these were not key mediators of the effect. However, focal adhesion formation, cytoskeletal organization, focal adhesion kinase (FAK) activation, and extracellular signal-regulated kinase (ERK) activation were all enhanced with increasing substrate stiffness. Inhibition of ERK activation substantially attenuated the effect of stiffness on proliferation. In long-term culture, hydrogel stiffness promoted the formation of more complete epithelial monolayers with tight junctions, cell polarity, and an organized basement membrane. These data suggest that increased stiffness potentially may have beneficial consequences for the renal tubular epithelium during recovery from AKI.