Department of Biomedical Experimental and Clinical Sciences "Mario Serio," University of Florence, Florence, Italy; Excellence Center DENOTHE, University of Florence, Florence, Italy; Nephrology and Dialysis Unit, Meyer Children's University Hospital, Florence, Italy. Electronic address: [Email]
Tubulointerstitial fibrosis is considered a hallmark of maladaptive repair processes after tubular injury leading to chronic kidney disease. Nakamura and colleagues show that, upon injury, myofibroblasts promote epithelial repair by producing retinoic acid in place of injured tubular cells. These results suggest that resident fibroblasts turning into myofibroblasts maintain a cross-talk that protects tubular epithelial cells from injury and can restore tissue integrity and functionality, challenging the concept that fibrosis is only detrimental in nature.