Abstract
Released mitochondrial DNA (mtDNA) in cells activates cGAS-STING
pathway, which induces expression of interferon-stimulated genes (ISGs) and
thereby promotes inflammation, as frequently seen in asthmatic airways.
However, whether the genetic determinant, Gasdermin B (GSDMB), the most
replicated asthma risk gene, regulates this pathway remains unknown.
We set out to determine whether and how GSDMB
regulates mtDNA-activated cGAS-STING pathway and subsequent
ISGs induction
in human airway epithelial cells. Using qPCR, ELISA, native polyacrylamide gel
electrophoresis, co-immunoprecipitation and immunofluorescence assays, we
evaluated the regulation of GSDMB on cGAS-STING pathway in both BEAS-2B cells
and primary normal human bronchial epithelial cells (nHBEs). mtDNA was
extracted in plasma samples from human asthmatics and the correlation between
mtDNA levels and eosinophil counts was analyzed.
GSDMB is significantly associated with
RANTES expression in
asthmatic nasal epithelial brushing samples from the Genes-environments and
Admixture in Latino Americans (GALA) II study. Over-expression of
GSDMB promotes DNA-induced IFN and
ISGs
expression in bronchial epithelial BEAS-2B cells and nHBEs. Conversely,
knockout of
GSDMB led to weakened
induction of
interferon (IFNs) and
ISGs in BEAS-2B cells.
Mechanistically, GSDMB interacts with the C-terminus of
STING, promoting the translocalization of STING to Golgi, leading to the
phosphorylation of IRF3 and induction of
IFNs and
ISGs. mtDNA
copy number in serum from asthmatics was significantly correlated with blood
eosinophil counts especially in male subjects. GSDMB
promotes the activation of mtDNA and poly (dA:dT)-induced activation of
cGAS-STING pathway in airway epithelial cells, leading to enhanced induction of
ISGs.
© 2024 by the authors; licensee SCIEPublish, SCISCAN co. Ltd. This article is an open access article distributed under the CC BY license (https://creativecommons.org/licenses/by/4.0/).