Related Experiment Video
Updated: May 10, 2025
Mechanism of Kemeng Fang's Inhibition of Podocyte Apoptosis in Rats with Membranous Nephropathy through the PI3K/AKT Signaling Pathway
Published on: August 23, 2024
AMPK is dispensable for physiological podocyte and glomerular functions but prevents glomerular fibrosis in
Swayam Prakash Srivastava1, Olivia Kopasz-Gemmen1, Abhiram Kunamneni1
1Life Sciences Institute, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, Michigan, 48109-2216, U.S.A.
Abstract:
AMP-activated protein kinase (AMPK) has been postulated to be crucial in regulating various renal physiology and pathophysiology processes, including energy metabolism, ion and water transport, inflammation, and hypertrophy. However, the specific roles of AMPK in the podocyte, a cell critical for maintaining glomerular filtration, have not been fully explored using genetic model animals. In this study, we generated mice lacking both AMPK α1 and α2 catalytic subunits in glomerular podocytes (pmut). Our findings revealed that, surprisingly, AMPK is dispensable for normal podocyte function. These knockout mice could live as long as their wild-type littermates without showing any pathological alterations in their glomeruli or glomerular function at two years of age. However, under type 1 diabetic conditions, the diabetic pmut mice exhibited increased lipid and collagen accumulation and an elevated expression of mesenchymal proteins in their glomeruli. They also showed more significant albuminuria compared to control diabetic mice. Under high glucose culture conditions, glomeruli isolated from pmut mice demonstrated a reduced expression of mitochondrial genes (e.g., Ndufv2) and increased leakage of mitochondrial components. Additionally, there was heightened expression of genes associated with nucleotide sensing and pro-inflammatory pathways (including mb21d2, IL-1 beta, and NF-kB). These observations suggest that while AMPK is not necessary for podocyte function in healthy kidneys, it is crucial for preventing glomerular fibrosis resulting from lipotoxicity and inflammation under diabetic conditions.
Insights
AMP-activated protein kinase (AMPK) is not essential for healthy podocyte function but is crucial for preventing kidney damage in diabetes by reducing fibrosis, lipotoxicity, and inflammation.
Area of Science:
- Nephrology
- Molecular Biology
- Metabolic Diseases
Background:
- AMP-activated protein kinase (AMPK) plays roles in renal physiology and pathophysiology.
- Its specific function in podocytes, critical for glomerular filtration, remains underexplored.
- Genetic models are needed to investigate podocyte AMPK roles.
Purpose of the Study:
- To investigate the role of AMPK in glomerular podocytes using a genetic knockout mouse model.
- To determine if podocyte-specific AMPK is essential for normal kidney function.
- To assess the impact of podocyte AMPK deficiency on diabetic nephropathy.
Main Methods:
- Generated podocyte-specific AMPK knockout mice (pmut) lacking α1 and α2 catalytic subunits.
- Assessed glomerular and kidney function in young and aged knockout mice under normal and type 1 diabetic conditions.
- Analyzed glomeruli from knockout mice under high glucose conditions for gene expression and mitochondrial integrity.
Main Results:
- Podocyte-specific AMPK knockout mice showed no abnormalities in healthy kidneys, living as long as wild-type littermates.
- Diabetic pmut mice exhibited increased albuminuria, glomerular lipid and collagen accumulation, and mesenchymal protein expression.
- Isolated glomeruli from pmut mice under high glucose displayed reduced mitochondrial gene expression, mitochondrial leakage, and heightened pro-inflammatory pathways.
Conclusions:
- AMPK is dispensable for normal podocyte function in healthy kidneys.
- Podocyte AMPK is crucial for mitigating glomerular fibrosis, lipotoxicity, and inflammation in type 1 diabetic conditions.
- Targeting podocyte AMPK may offer a therapeutic strategy for diabetic nephropathy.
Related Concept Videos
01:25cAMP-dependent Protein Kinase Pathways
01:22PI3K/mTOR/AKT Signaling Pathway
01:23Dipeptidyl Peptidase 4 Inhibitors