Elevated Phosphate Levels Trigger Autophagy-Mediated Cellular Apoptosis in H9c2 Cardiomyoblasts

Area of Science:

• Cardiovascular Biology
• Cellular Biology
• Renal Physiology

Background:

• Chronic kidney disease (CKD) impairs phosphorus homeostasis, leading to hyperphosphatemia.
• Elevated serum phosphorus is linked to cardiovascular disease in CKD and healthy individuals.

Purpose of the Study:

• To investigate autophagy and apoptosis markers in myocardial cells under hyperphosphatemia.
• To elucidate the role of the pAMPK signaling pathway in hyperphosphatemia-induced cardiac cell damage.

Main Methods:

• Western blotting to analyze autophagy and apoptosis-related protein levels.
• FITC-annexin V staining to quantify apoptotic cells.
• Treatment with hyperphosphate and an autophagy inhibitor (3-Methyladenine).

Main Results:

• Hyperphosphatemia upregulated autophagy proteins (beclin-1, ATG7, LC3 II) via the pAMPK-ULK1 pathway.
• Hyperphosphatemia also increased apoptosis markers (Bax, Bid, cytochrome c, c-caspase-9).
• Autophagy inhibition significantly reduced apoptosis and specific apoptosis-related proteins.

Conclusions:

• Hyperphosphatemia induces apoptosis in H9c2 cardiomyoblasts through autophagy, mediated by the pAMPK pathway.
• This study reveals a potential mechanism for cardiac damage in hyperphosphatemia.