Podocyte-specific deletion of tubular sclerosis complex 2 promotes focal segmental glomerulosclerosis and progressive...

Area of Science:

• Nephrology
• Metabolic disease research
• Cellular biology

Background:

• Obesity is a significant risk factor for chronic kidney disease (CKD).
• The precise mechanisms by which obesity induces renal dysfunction, particularly in podocytes, are not fully understood.
• Podocyte injury is a key feature of many proteinuric kidney diseases.

Purpose of the Study:

• To investigate the role of tubular sclerosis complex 2 (Tsc2) in podocyte function and its link to obesity-related kidney disease.
• To explore the mammalian target of rapamycin (mTOR) pathway as a potential therapeutic target in this context.

Main Methods:

• Generation and analysis of a podocyte-specific Tsc2 knockout mouse model (Tsc2Δpodocyte).
• Assessment of renal pathology, including glomerular size, glomerulosclerosis, and podocyte structure.
• Microarray analysis of podocytes to evaluate oxidative stress and autophagic activity.
• Treatment with rapamycin to assess its therapeutic effects.
• Analysis of renal biopsy specimens from obese CKD patients.

Main Results:

• Tsc2Δpodocyte mice developed severe proteinuria, end-stage renal dysfunction, increased glomerular size, and focal segmental glomerulosclerosis.
• Podocytes from Tsc2Δpodocyte mice exhibited increased oxidative stress and reduced autophagic activity via the mTOR-unc-51-like kinase 1 pathway.
• Rapamycin treatment attenuated podocyte dysfunction and improved survival in Tsc2Δpodocyte mice.
• Increased mTOR complex 1 (mTORC1) activity was observed in podocytes of obese CKD patients.

Conclusions:

• Hyperactivation of mTORC1 in podocytes contributes to severe renal dysfunction.
• Targeting mTORC1 activity in podocytes represents a potential therapeutic strategy for obesity-related kidney diseases.