Aurintricarboxylic acid mitigates cigarette smoke extract induced oxidative stress and pulmonary inflammation via inhibition of NF-ҡB/p65 signaling

Abstract

Cigarette smoke (CS) induced emphysema and chronic pulmonary inflammation are major comorbidities of chronic obstructive pulmonary disease (COPD), a major cause of morbidity and mortality worldwide. CS exposure exacerbates pulmonary inflammation and compromises immunity to various infections. Aurintricarboxylic acid (ATA) is a polyanionic aromatic compound especially recognized for its anti-inflammatory, nucleic acid, and protein interaction inhibition properties. The study was designed to investigate the anti-inflammatory role of ATA against cigarette smoke extract (CSE) induced pulmonary inflammation. Nicotine concentration was quantified in CSE by UPLC/MS technique. In vitro, fluorescence microscopy, and flow cytometry was performed in CSE stimulated alveolar epithelial cells to determine the effect of ATA on oxidative stress-mediated cellular apoptosis. In vivo, pulmonary inflammation was induced in male Wistar rats via a modified non-invasive intratracheal instillation of cigarette smoke extract (100 µl/animal) twice a week for 8 weeks and post-treated with ATA (10 mg/kg) intraperitoneally for 15 days. Lung homogenates were assessed for MDA and GSH. Lung tissues were subjected to western blotting and histopathological analysis. As result, ATA reduced CSE-induced chromatin condensation, fragmentation, cellular apoptosis in alveolar epithelial cells, and apoptotic biomarkers expression including BAX and Caspase-3 in the lungs. ATA reduced inflammation by normalizing redox balance reflected by MDA/GSH levels. ATA obviated airspace enlargement, fiber deposition, and immune cell infiltration. Reduced inflammation was accompanied by inhibition of inflammatory biomarkers TNF-α, TNFR1, TWEAK, and NF-ҡB/p65 activation and nuclear translocation. ATA efficaciously diminished the oxidative stress and pulmonary inflammation associated with lung pathogenesis through TNF-α/TNFR1/NF-ҡB/p65 signaling pathway.

HIGHLIGHTS

• ATA treatment attenuates CSE-stimulated chromatin condensation, fragmentation, and cellular apoptosis in alveolar epithelial cells.

• ATA treatment inhibits CSE stimulated activation and nuclear translocation of NF-ҡB/p65.

• ATA treatment diminishes CSE-induced oxidant injury, apoptosis, and emphysema-like phenotypic changes in the lungs.

• ATA inhibits lung inflammation via suppression of the NF-ҡB/p65 signaling pathway.

Keywords:

• Aurintricarboxylic acid (ATA)
• cigarette smoke extract (CSE)
• oxidative stress
• lung inflammation
• NF-ҡB/p65
• apoptosis

Acknowledgments

We would like to thank the Director of the Council of Scientific and Industrial Research-Central Drug Research Institute (CSIR-CDRI), Lucknow, India, for sustained and unconditional support during the experiment. The authors are grateful to Dr. Chandra Prakash Pandey and Mr. V. L. Vishwakarma for providing technical assistance for fluorescence microscopy and flow cytometry. CDRI communication number 10424.

Author contributions

The study was designed by BM and KD, In vitro and in vivo study was performed by KD, and LC/MS study was done by YS. In vitro and in vivo data analysis was conducted by KD and BM. LC/MS data analysis was done by YS and SK. Data interpretation and manuscript drafting was done by BM, KD, YS, and SK. The final version of the manuscript was approved by BM.

Ethical approval

All animal experiments were performed following the Institutional Animal Ethical Committee (IAEC) following the guidelines of the Committee for the Purpose of Control and Supervision of Experiments on animals (CPCSEA), India. IAEC approval number is IAEC/2019/21/Renew/-0/Dated-04/01/2019.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This research work is financially supported by the Council of Scientific and Industrial Research (CSIR) in-house network grant [OLP0101] to BM. The CSIR-CDRI communication number is 130/2020/BM. KD and YS is funded by a research fellowship from CSIR, New Delhi, India.