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Updated: Jan 16, 2026
Visualization of Inflammatory Caspases Induced Proximity in Human Monocyte-Derived Macrophages
Published on: April 6, 2022
A Caspase-1-cathepsin AND-Gate Probe for Selective Imaging of Inflammasome Activation
Shiyu Chen1, Una Goncin2, Jiyun Zhu1
1Department of Pathology, Stanford University School of Medicine, Stanford, California 94305, United States.
Abstract:
Caspase-1 is a key mediator of the inflammasome pathway, which is associated with several inflammatory disorders including obesity, diabetes mellitus, cardiovascular diseases, cancers, and chronic respiratory diseases. Although substrate-based probes can be used to visualize the activity of caspase-1, none are selective enough for use as imaging agents. Here, we report the design and synthesis of an AND-gate substrate probe (Cas1-Cat-Cy7) that requires processing by both caspase-1 and cathepsins to produce a signal. Because both enzymes are found together and active in tissue locations where cells are undergoing caspase-1-mediated pyroptosis, the resulting probe can be used to image sites of caspase-1-mediated inflammation. We demonstrate that the probe produces selective signals in ex vivo biochemical and cellular assays and in a mouse model of acute inflammation.
Insights
A novel probe, Cas1-Cat-Cy7, enables selective imaging of caspase-1 activity in inflammation. This tool aids in visualizing inflammatory processes by requiring dual enzyme activation for signal generation.
Area of Science:
- Biomedical imaging
- Molecular biology
- Inflammation research
Background:
- Caspase-1 is a crucial enzyme in inflammasome pathways linked to various inflammatory diseases.
- Current caspase-1 probes lack the selectivity needed for effective in vivo imaging.
- Inflammasome activation is implicated in conditions like obesity, diabetes, cardiovascular diseases, cancers, and respiratory diseases.
Purpose of the Study:
- To design and synthesize a novel, selective imaging probe for caspase-1 activity.
- To develop a tool for visualizing caspase-1-mediated inflammation and pyroptosis.
Main Methods:
- Design and synthesis of an AND-gate substrate probe (Cas1-Cat-Cy7).
- The probe requires sequential processing by caspase-1 and cathepsins for signal activation.
- Validation using ex vivo biochemical and cellular assays.
- Testing in a mouse model of acute inflammation.
Main Results:
- The Cas1-Cat-Cy7 probe demonstrated high selectivity for caspase-1 activity.
- The AND-gate mechanism ensured signal generation only in the presence of both target enzymes.
- Successful visualization of inflammation in ex vivo and in vivo models.
Conclusions:
- Cas1-Cat-Cy7 is a selective and effective probe for imaging caspase-1-mediated inflammation.
- This probe facilitates the study of pyroptosis and inflammatory processes.
- The developed probe holds potential for advancing diagnostic and research applications in inflammatory diseases.
