Hair Follicle Transit-Amplifying Cells Phagocytose Dead Cells after Radiotherapeutic and Chemotherapeutic Injuries for Timely Regeneration
Journal
The Journal of investigative dermatology
Journal Volume
144
Journal Issue
2
Start Page
243
End Page
251.e2
ISSN
0022-202X
Date Issued
2024-02
Author(s)
Wang, Wei-Hung
Hsu, Yao-Wen
Tee, Suet Yee
Wu, Yueh-Feng
Huang, Wen-Yen
Abstract
Efficient clearance of dead cells is critical for tissue regeneration after injuries. How dead cells are removed from the skin after radiotherapy and chemotherapy is unclear. In this study, we found that radiotherapeutic and chemotherapeutic damage induced extensive apoptosis of highly proliferative transit-amplifying cells in hair follicles. These apoptotic cells disappeared rapidly in the early stage of regenerative attempts, and the lost structures were regenerated with transient and low-level inflammation. Without the recruitment of macrophages as scavengers, the dying cells were engulfed directly by adjacent surviving transit-amplifying cells, which produced mature phagosomes through fusion with lysosomes in a manner similar to professional phagocytosis and remained active in proliferation. Autophagy did not contribute significantly to the clearance of engulfed cell debris. Perturbing phagocytosis in the transit-amplifying cells hindered apoptotic cell removal, delayed structural recovery, and aggravated hair loss. Therefore, transit-amplifying cells are capacitated with both proliferative and efferocytic functions that facilitate tissue regeneration after tissue injury.
Type
journal article