
LIGHT / IFN ‐γ triggers β cells apoptosis via NF ‐κB/Bcl2‐dependent mitochondrial pathway
Author(s) -
Zheng QuanYou,
Cao ZhaoHui,
Hu XiaoBo,
Li GuiQing,
Dong ShiFang,
Xu GuiLian,
Zhang KeQin
Publication year - 2016
Publication title -
journal of cellular and molecular medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.44
H-Index - 130
eISSN - 1582-4934
pISSN - 1582-1838
DOI - 10.1111/jcmm.12876
Subject(s) - pyrrolidine dithiocarbamate , apoptosis , viability assay , microbiology and biotechnology , biology , poly adp ribose polymerase , annexin , programmed cell death , flow cytometry , chemistry , nf κb , biochemistry , polymerase , gene
LIGHT recruits and activates naive T cells in the islets at the onset of diabetes. IFN ‐γ secreted by activated T lymphocytes is involved in beta cell apoptosis. However, whether LIGHT sensitizes IFN γ‐induced beta cells destruction remains unclear. In this study, we used the murine beta cell line MIN 6 and primary islet cells as models for investigating the underlying cellular mechanisms involved in LIGHT / IFN γ – induced pancreatic beta cell destruction. LIGHT and IFN ‐γ synergistically reduced MIN 6 and primary islet cells viability; decreased cell viability was due to apoptosis, as demonstrated by a significant increase in Annexin V + cell percentage, detected by flow cytometry. In addition to marked increases in cytochrome c release and NF ‐κB activation, the combination of LIGHT and IFN ‐γ caused an obvious decrease in expression of the anti‐apoptotic proteins Bcl‐2 and Bcl‐ xL , but an increase in expression of the pro‐apoptotic proteins Bak and Bax in MIN 6 cells. Accordingly, LIGHT deficiency led to a decrease in NF ‐κB activation and Bak expression, and peri‐insulitis in non‐obese diabetes mice. Inhibition of NF ‐κB activation with the specific NF ‐κB inhibitor, PDTC (pyrrolidine dithiocarbamate), reversed Bcl‐ xL down‐regulation and Bax up‐regulation, and led to a significant increase in LIGHT ‐ and IFN ‐γ‐treated cell viability. Moreover, cleaved caspase‐9, ‐3, and PARP (poly ( ADP ‐ribose) polymerase) were observed after LIGHT and IFN ‐γ treatment. Pretreatment with caspase inhibitors remarkably attenuated LIGHT ‐ and IFN γ‐induced cell apoptosis. Taken together, our results indicate that LIGHT signalling pathway combined with IFN ‐γ induces beta cells apoptosis via an NF ‐κB/Bcl2‐dependent mitochondrial pathway.