Loss of endogenous thymosin β4accelerates glomerular disease.
Vasilopoulou E., Kolatsi-Joannou M., Lindenmeyer MT., White KE., Robson MG., Cohen CD., Sebire NJ., Riley PR., Winyard PJ., Long DA.
Glomerular disease is characterized by morphologic changes in podocyte cells accompanied by inflammation and fibrosis. Thymosin β4regulates cell morphology, inflammation, and fibrosis in several organs and administration of exogenous thymosin β4improves animal models of unilateral ureteral obstruction and diabetic nephropathy. However, the role of endogenous thymosin β4in the kidney is unknown. We demonstrate that thymosin β4is expressed prominently in podocytes of developing and adult mouse glomeruli. Global loss of thymosin β4did not affect healthy glomeruli, but accelerated the severity of immune-mediated nephrotoxic nephritis with worse renal function, periglomerular inflammation, and fibrosis. Lack of thymosin β4in nephrotoxic nephritis led to the redistribution of podocytes from the glomerular tuft toward the Bowman capsule suggesting a role for thymosin β4in the migration of these cells. Thymosin β4knockdown in cultured podocytes also increased migration in a wound-healing assay, accompanied by F-actin rearrangement and increased RhoA activity. We propose that endogenous thymosin β4is a modifier of glomerular injury, likely having a protective role acting as a brake to slow disease progression.