BACKGROUND/AIMS: Age-associated and stress-induced involution of the thymus is accompanied by reduced numbers of thymic epithelial cells (TECs) and severe reduction in peripheral T cell repertoire specificities. These events seriously affect immune function, but the mechanisms involved are unclear. Our preliminary findings showed that doxycycline (Dox) could drive the proliferation of a TEC line (MTEC1 cells) partially via the MAPK signaling pathway. Dox can also up-regulate IL-6 and GM-CSF expression via the NF-κB and MAPK/ERK pathways. Herein, we investigate the effects and mechanisms used by Dox that protect against mitomycin C (MMC)-induced MTEC1 cell apoptosis. METHODS: MTEC1 cells were treated with Dox, MMC, and Dox plus MMC for different amounts of time. The expression of Trx2, NF-κB, Bcl-2, and Bax proteins were then detected by western blotting. RESULTS: Our findings show that Dox protects MTEC1 cells from MMC-induced apoptosis. Dox up-regulated the expression of Trx2 and promoted NF-κB phosphorylation. Meanwhile, Dox also increased the expression of Bcl-2, partially reduced the expression of Bax, and normalized the ratio of Bcl-2 to Bax. CONCLUSION: Dox exerts an anti-apoptosis function via the NF-κB-Bcl-2/Bax and Trx2-ASK1/JNK pathways in vitro. Therefore, Dox may represent a drug that could be used to attenuate thymic senescence, rescue thymic function, and promote T cell reconstitution.
BACKGROUND/AIMS: Age-associated and stress-induced involution of the thymus is accompanied by reduced numbers of thymic epithelial cells (TECs) and severe reduction in peripheral T cell repertoire specificities. These events seriously affect immune function, but the mechanisms involved are unclear. Our preliminary findings showed that doxycycline (Dox) could drive the proliferation of a TEC line (MTEC1 cells) partially via the MAPK signaling pathway. Dox can also up-regulate IL-6 and GM-CSF expression via the NF-κB and MAPK/ERK pathways. Herein, we investigate the effects and mechanisms used by Dox that protect against mitomycin C (MMC)-induced MTEC1 cell apoptosis. METHODS: MTEC1 cells were treated with Dox, MMC, and Dox plus MMC for different amounts of time. The expression of Trx2, NF-κB, Bcl-2, and Bax proteins were then detected by western blotting. RESULTS: Our findings show that Dox protects MTEC1 cells from MMC-induced apoptosis. Dox up-regulated the expression of Trx2 and promoted NF-κB phosphorylation. Meanwhile, Dox also increased the expression of Bcl-2, partially reduced the expression of Bax, and normalized the ratio of Bcl-2 to Bax. CONCLUSION:Dox exerts an anti-apoptosis function via the NF-κB-Bcl-2/Bax and Trx2-ASK1/JNK pathways in vitro. Therefore, Dox may represent a drug that could be used to attenuate thymic senescence, rescue thymic function, and promote T cell reconstitution.
Authors: Mu Seog Choe; Chang Min Bae; So Jin Kim; Seung Tack Oh; Yu Jin Kown; Won-Young Choi; Ho Jae Han; Kyung Min Baek; Woochul Chang; Joong Sun Kim; Kyung Seob Lim; Seung Pil Yun; Min Young Lee Journal: Cell Mol Life Sci Date: 2022-10-11 Impact factor: 9.207