Increased level of phosphorylated desmin and its degradation products in heart failure

Area of Science:

• Biochemistry
• Cardiovascular Research
• Proteomics

Background:

• Predicting heart failure (HF) progression is challenging despite known risk factors like infarct size.
• Current clinical practice lacks reliable biomarkers for HF severity.
• Desmin, a cytoskeletal protein, is implicated in cardiac function.

Purpose of the Study:

• To investigate if desmin, specifically its phosphorylated form, serves as a circulating or tissue biomarker for heart failure (HF).
• To determine the presence and form of desmin in cardiac tissue and plasma of a heart failure model.

Main Methods:

• Utilized an experimental rat model of ischemic heart failure (HF).
• Employed phosphoproteomic technology, western blotting, mass spectrometry, and immunofluorescence to analyze desmin.
• Investigated desmin, its fragments, and phosphorylated forms in left ventricle (LV) tissue and plasma.
• Applied plasma treatments (combinatorial peptide ligand library, albumin/immunoglobulin depletion) to enhance detection sensitivity.

Main Results:

• Observed a 2-fold increase in serine-desmin phosphorylation in the LV of HF rats, predominantly in insoluble fractions, indicating aggregate formation.
• Detected desmin cleavage products in the LV of HF rats, suggesting increased susceptibility to proteolysis (e.g., calpain activity) due to phosphorylation.
• Found native desmin and its degradation products were undetectable in the plasma of rats, mice, and humans.

Conclusions:

• Phosphorylated desmin and its degradation products show potential as tissue-specific biomarkers for heart failure (HF).
• Desmin itself is not a reliable circulating biomarker for HF.
• Further research could validate these findings for clinical application in HF diagnosis and prognosis.