Related Experiment Video
Updated: Oct 23, 2025
Evaluating Cell Death Signaling by Immunofluorescence in a Rat Model of Ischemic Stroke
Published on: January 3, 2025
Expression of Cathepsins B, D, and G in Extracranial Arterio-Venous Malformation
Lauren Hansen1, Helen D Brasch1, Erin Paterson1
1Gillies McIndoe Research Institute, Wellington, New Zealand.
Insights
This study found cathepsins B, D, and G in arterio-venous malformations (AVM). Cathepsins B and D were linked to primitive stem cell-like populations, while cathepsin G was found in mast cells within the AVM.
Area of Science:
- Vascular Biology
- Cell Biology
- Biochemistry
Background:
- Extracranial arterio-venous malformations (AVM) exhibit stemness-associated markers.
- Cathepsins B, D, and G have been observed in embryonic stem cell (ESC)-like populations in other vascular anomalies.
Purpose of the Study:
- To investigate the expression and localization of cathepsins B, D, and G in extracranial AVM.
- To determine the relationship between cathepsin expression and primitive cell populations in AVM.
Main Methods:
- Immunohistochemistry on 13 AVM tissue samples.
- Western blotting and RT-qPCR on AVM tissues and cell lines.
- Enzymatic activity assays for cathepsins B and D.
- Immunofluorescence dual-staining with stem cell and mast cell markers.
Main Results:
- Cathepsins B, D, and G were expressed in all AVM tissue samples.
- Cathepsins B and D proteins and transcripts were confirmed in AVM tissues and cell lines.
- Active cathepsins B and D were detected.
- Cathepsins B and D localized to primitive OCT4+/SOX2+ cells, while cathepsin G localized to mast cells.
Conclusions:
- This study reveals the novel expression of cathepsins B, D, and G in AVM.
- Cathepsins B and D are associated with the primitive cell population in AVM.
- Cathepsin G is localized to mast cells within the AVM nidus.
Abstract:
Objectives: We have previously identified a population of cells that expressed stemness-associated markers in extracranial arterio-venous malformation (AVM) and demonstrated expression of cathepsins B, D, and G on embryonic stem cell (ESC)-like populations in other vascular anomalies. This study investigated the expression of cathepsins B, D, and G, and their localization in relation to this primitive population in extracranial AVM. Methods: Immunohistochemical staining was performed on AVM tissue samples from 13 patients to demonstrate expression of cathepsins B, D, and G. Western blotting was performed on four AVM tissue samples and three AVM-derived primary cell lines to confirm protein expression of cathepsins B and D proteins. RT-qPCR was performed on three AVM-derived primary cell lines to demonstrate transcript expression of cathepsins B, D, and G. Enzymatic activity assays were performed on three AVM-derived primary cell lines to investigate if cathepsins B and D were active. Localization of the cathepsins was investigated using immunofluorescence dual-staining of the cathepsins with the ESC markers OCT4 and SOX2, and mast cells marker chymase on two of the 13 AVM tissue samples. Results: Immunohistochemical staining demonstrated expression of cathepsins B, D, and G in all 13 AVM tissue samples. Western blotting showed expression of cathepsins B and D proteins in all four AVM tissue samples and all three AVM-derived primary cell lines. RT-qPCR demonstrated transcripts of cathepsins B, D, and G in all three AVM-derived primary cell lines. Enzymatic activity assays showed that cathepsins B and D were active. Immunofluorescence staining showed expression of cathepsins B and D on the OCT4+/SOX2+ endothelium and media of the lesional vessels and cells within the stroma in AVM nidus. Cathepsin G was expressed on the chymase+ phenotypic mast cells. Conclusions: This study demonstrated the novel finding of the expression of cathepsins B, D, and G in AVM. Cathepsins B and D were expressed by the primitive population, and cathepsin G was localized to mast cells, within the AVM nidus.
