Autophagy influences glomerular disease susceptibility and maintains podocyte homeostasis in aging mice

Area of Science:

• Nephrology
• Cellular Biology
• Molecular Medicine

Background:

• Podocyte injury and loss are primary drivers of glomerular disease and renal failure.
• The mechanisms by which podocytes, a postmitotic cell type, cope with cellular stress remain poorly understood.
• Autophagy is a critical cellular pathway for degrading damaged proteins and organelles, maintaining homeostasis.

Purpose of the Study:

• To investigate the role of autophagy in podocyte stress response and maintenance of kidney function.
• To determine the impact of impaired autophagy on podocyte integrity and the development of glomerular disease.

Main Methods:

• Generated podocyte-specific autophagy-related 5 (Atg5) knockout mice.
• Analyzed kidney pathology, protein accumulation, ER stress, and proteinuria in knockout and wild-type mice.
• Examined autophagy levels in mouse models of induced proteinuria and human proteinuric kidney diseases.

Main Results:

• Podocytes exhibit high constitutive autophagy levels.
• Podocyte-specific Atg5 deletion induced glomerulopathy, characterized by protein aggregation, ER stress, and proteinuria.
• Impaired autophagy led to podocyte loss, glomerulosclerosis, and increased susceptibility to glomerular injury models.
• Autophagy was significantly upregulated in conditions of proteinuria in mice and humans.

Conclusions:

• Constitutive and induced autophagy is essential for maintaining podocyte integrity and preventing glomerular injury.
• Impaired autophagy contributes to podocyte aging and the pathogenesis of proteinuric kidney diseases.
• Targeting autophagy pathways may offer a therapeutic strategy for human glomerular diseases and age-related kidney dysfunction.