PAPP-A-Specific IGFBP-4 Proteolysis in Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes
The insulin-like growth factors IGF-I and IGF-II—as well as their binding proteins (IGFBPs), which regulate their bioavailability—are involved in many pathological and physiological processes in cardiac tissue. Pregnancy-associated plasma protein A (PAPP-A) is a metalloprotease that preferentially c...
| Main Authors: | , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2023-05-01
|
| Series: | International Journal of Molecular Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1422-0067/24/9/8420 |
| Summary: | The insulin-like growth factors IGF-I and IGF-II—as well as their binding proteins (IGFBPs), which regulate their bioavailability—are involved in many pathological and physiological processes in cardiac tissue. Pregnancy-associated plasma protein A (PAPP-A) is a metalloprotease that preferentially cleaves IGFBP-4, releasing IGF and activating its biological activity. Previous studies have shown that PAPP-A-specific IGFBP-4 proteolysis is involved in the pathogenesis of cardiovascular diseases, such as ischemia, heart failure, and acute coronary syndrome. However, it remains unclear whether PAPP-A-specific IGFBP-4 proteolysis participates in human normal cardiomyocytes. Here, we report PAPP-A-specific IGFBP-4 proteolysis occurring in human cardiomyocytes derived from two independent induced pluripotent cell lines (hiPSC-CMs), detected both on the cell surface and in the cell secretome. PAPP-A was measured by fluoroimmune analysis (FIA) in a conditioned medium of hiPSC-CMs and was detected in concentrations of up to 4.3 ± 1.33 ng/mL and 3.8 ± 1.1 ng/mL. The level of PAPP-A-specific IGFBP-4 proteolysis was determined as the concentration of NT-IGFBP-4 proteolytic fragments using FIA for a proteolytic neo-epitope-specific assay. We showed that PAPP-A-specific IGFBP-4 proteolysis is IGF-dependent and inhibited by EDTA and 1,10-phenanthroline. Therefore, it may be concluded that PAPP-A-specific IGFBP-4 proteolysis functions in human normal cardiomyocytes, and hiPSC-CMs contain membrane-bound and secreted forms of proteolytically active PAPP-A. |
|---|---|
| ISSN: | 1661-6596 1422-0067 |