A novel apoptosis probe, cyclic ApoPep-1, for in vivo imaging with multimodal applications in chronic inflammatory arthritis

In Seop So, Jin Hee Kang, Jung Wan Hong, Shijin Sung, Al Faruque Hasan, Keum Hee Sa, Seung Woo Han, In San Kim, Young Mo Kang

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Apoptosis plays an essential role in the pathophysiologic processes of rheumatoid arthritis. A molecular probe that allows spatiotemporal observation of apoptosis in vitro, in vivo, and ex vivo concomitantly would be useful to monitoring or predicting pathophysiologic stages. In this study we investigated whether cyclic apoptosis-targeting peptide-1 (CApoPep-1) can be used as an apoptosis imaging probe in inflammatory arthritis. We tested the utility of CApoPep-1 for detecting apoptotic immune cells in vitro and ex vivo using flow cytometry and immunofluorescence. The feasibility of visualizing and quantifying apoptosis using this probe was evaluated in a murine collagen-induced arthritis (CIA) model, especially after treatment. CApoPep-1 peptide may successfully replace Annexin V for in vitro and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay for ex vivo in the measurement of apoptotic cells, thus function as a sensitive probe enough to be used clinically. In vivo imaging in CIA mice revealed that CApoPep-1 had 42.9 times higher fluorescence intensity than Annexin V for apoptosis quantification. Furthermore, it may be used as an imaging probe for early detection of apoptotic response in situ after treatment. The CApoPep-1 signal was mostly co-localized with the TUNEL signal (69.6% of TUNEL+ cells) in defined cell populations in joint tissues of CIA mice. These results demonstrate that CApoPep-1 is sufficiently sensitive to be used as an apoptosis imaging probe for multipurpose applications which could detect the same target across in vitro, in vivo, to ex vivo in inflammatory arthritis.

Original languageEnglish
Pages (from-to)209-218
Number of pages10
Issue number3-4
Publication statusPublished - 2021 Apr
Externally publishedYes

Bibliographical note

Funding Information:
This work was supported by grants from the Basic Research Program of the National Research Foundation, Republic of Korea (No. NRF-2017R1A2B2008288 and NRF-2018R1C1B6006259) and the Korean Healthcare Technology R&D Project (No. HI18C2112).

Publisher Copyright:
© 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC part of Springer Nature.


  • Apoptosis imaging
  • Cyclic ApoPep-1
  • Multipurpose applications
  • Probe
  • Rheumatoid arthritis

ASJC Scopus subject areas

  • Pharmacology
  • Pharmaceutical Science
  • Clinical Biochemistry
  • Cell Biology
  • Biochemistry, medical
  • Cancer Research


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