Apurinic/apyrimidinic endonuclease 1/reduction-oxidation effector factor-1 (APE1) regulates the expression of NLR family pyrin domain containing 3 (NLRP3) inflammasome through modulating transcription factor NF-?B and promoting the secretion of inflammatory mediators in macrophages.

ABSTRACT:

Background

Inflammatory mediators play an important role in the occurrence, development, and metastasis of tumors. The aim of the present study was to elucidate the effect of apurinic/apyrimidinic endonuclease 1/reduction-oxidation effector factor-1 (APE1) on inflammatory mediator secretion, which is dependent on the APE1-mediated NLR family pyrin domain containing 3 (NLRP3) regulatory mechanism.

Methods

The human myeloid leukemia mononuclear cell line (THP-1) cells were cultured and polarized to M2 subset macrophages. Enzyme-linked immunosorbent assay was used for determining tumor necrosis factor-? (TNF-?), interleukin (IL)-1?, IL-18, IL-10, and IL-33 levels. Reverse transcription-polymerase chain reaction and western blot were used for evaluating TNF-?, NLR family pyrin domain containing 1 (NLRP1), NLRP3, caspase-1, and apoptosis-associated speck-like protein containing a card expression. Plasmid silencing APE1 gene (APE1^shRNA) was synthesized and packaged into lentiviral. For activating inflammasomes, M2-type THP-1 cells were transfected with lentiviral vector APE1^shRNA incubated with lipopolysaccharide (LPS) (100 ng/mL)/APE1 inhibitor (E3330, 20 µM) and ATP. Electrophoretic mobility shift assay and dual-luciferase reporter assay were used for determining the interaction between NLRP3 and nuclear factor-?B (NF-?B) molecule.

Results

APE1 significantly induced LPS-induced pro-inflammatory cytokine production, including TNF-?, IL-1?, and IL18, compared with THP-1 cells without APE1 treatment (P<0.05). APE1 promoted LPS-induced NLRP3 inflammasome activation by modulating the gene transcription of NLRP3-associated molecules. APE1 enhanced LPS-induced NLRP3 inflammasome activation by regulating NLRP3 and caspase-1 protein expression. APE1 improved NLRP3 activity by modulating the interaction between NLRP3 and NF-?B, and the modulation of NF-?B. APE1 promoted LPS-induced NLRP3 inflammasome activation through an NF-?B-dependent pathway.

Conclusions

APE1 regulates the expression of NLRP3 by modulating transcription factor NF-?B and further promoting the secretion of inflammatory mediators IL-1? and IL-18 in macrophages. The findings of the present study provide theoretical and experimental bases for the design of tumor-associated macrophage (TAM)-targeted therapy, with APE1 as the target molecule.

SUBMITTER: Tang Z 

PROVIDER: S-EPMC7867945 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature