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circHECTD1 attenuates apoptosis of alveolar epithelial cells in acute lung injury


Circular RNAs (circRNAs) play important roles in many lung diseases. This study aimed to investigate the role of circHECTD1 in acute lung injury (ALI). The mouse and cell models of ALI were induced by lipopolysaccharide (LPS). The apoptosis of alveolar epithelial cells (AECs) was detected by flow cytometry. The relationships between circHECTD1, miRNAs, and target genes were assessed by RNA pull-down, luciferase reporter gene, and RNA-FISH assays. circHECTD1 was downregulated in LPS-induced human and mouse AECs (HBE and MLE-12). The knockdown of circHECTD1 increased the apoptotic rates and the expressions of miR-136 and miR-320a, while its overexpression caused opposite effects in LPS-induced HBE and MLE-12 cells. Mechanistically, circHECTD1 bound to miR-320a and miR-136. miR-320a targeted PIK3CA and mediated the effect of circHECTD1 on PIK3CA expression. miR-136 targeted Sirt1 and mediated the effect of circHECTD1 on Sirt1 expression. Silencing PIK3CA and/or Sirt1 reversed the effect of circHECTD1 overexpression on the apoptosis of LPS-induced HBE and MLE-12 cells. In vivo, overexpression of circHECTD1 alleviated the LPS-induced ALI of mice. Our findings suggested that circHECTD1 inhibits the apoptosis of AECs through miR-320a/PIK3CA and miR-136/Sirt1 pathways in LPS-induced ALI.

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Fig. 1: The expression of circHECTD1 in LPS-induced alveolar epithelial cells (AECs).
Fig. 2: The effect of circHECTD1 on the apoptosis of AECs.
Fig. 3: circHECTD1 binds to miR-136 and miR-320 in AECs.
Fig. 4: circHECTD1 regulates PIK3CA expression through miR-320a.
Fig. 5: circHECTD1 regulates Sirt1 expression through miR-136.
Fig. 6: Sirt1 and PIK3CA mediate the effect of circHECTD1 on apoptosis of AECs.
Fig. 7: circHECTD1 relieves ALI of mice. ALI mice were divided into two groups: the Ad-circHECTD1 group (n = 7) and the Ad-GFP group (n = 7).

Data availability

All the data generated or analyzed during this study are included in the manuscript.


  1. Villar, J. et al. The ALIEN study: Incidence and outcome of acute respiratory distress syndrome in the era of lung protective ventilation. Intensive Care Med. 37, 1932–1941 (2011).

    PubMed  Article  Google Scholar 

  2. Blank, R. & Napolitano, L. M. Epidemiology of ARDS and ALI. Crit. Care Clin. 27, 439–458 (2011).

    PubMed  Article  Google Scholar 

  3. Bocharov, A. V. et al. Synthetic amphipathic helical peptides targeting CD36 attenuate lipopolysaccharide-induced inflammation and acute lung injury. J. Immunol. 197, 611–619 (2016).

    CAS  PubMed  Article  Google Scholar 

  4. Bardales, R. H., Xie, S. S., Schaefer, R. F. & Hsu, S. M. Apoptosis is a major pathway responsible for the resolution of type II pneumocytes in acute lung injury. Am. J. Pathol. 149, 845–852 (1996).

    CAS  PubMed  PubMed Central  Google Scholar 

  5. MacRedmond, R., Singhera, G. K. & Dorscheid, D. R. Erythropoietin inhibits respiratory epithelial cell apoptosis in a model of acute lung injury. Eur. Respir. J. 33, 1403–1414 (2009).

    CAS  PubMed  Article  Google Scholar 

  6. Bem, R. A., Bos, A. P., Matute-Bello, G., van Tuyl, M. & van Woensel, J. B. M. Lung epithelial cell apoptosis during acute lung injury in infancy. Pediatr. Crit. Care Med. 8, 132–137 (2007).

    PubMed  Article  Google Scholar 

  7. Hansen, T. B. et al. Natural RNA circles function as efficient microRNA sponges. Nature 495, 384–388 (2013).

    CAS  PubMed  Article  Google Scholar 

  8. Sang, Y. et al. circRNA_0025202 regulates tamoxifen sensitivity and tumor progression via regulating the miR-182-5p/FOXO3a axis in breast cancer. Mol Ther. 27, 1638–1652 (2019).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  9. Li, H. et al. Circular RNA circRNA_000203 aggravates cardiac hypertrophy via suppressing miR26b-5p and miR-140-3p binding to Gata4. Cardiovasc. Res. 116, 1323–1334 (2019).

    PubMed Central  Article  Google Scholar 

  10. Dong, W. et al. Circular RNA ACVR2A suppresses bladder cancer cells proliferation and metastasis through miR-626/EYA4 axis. Mol. Cancer 18, 95–95 (2019).

    PubMed  PubMed Central  Article  Google Scholar 

  11. Garikipati, V. N. S. et al. Circular RNA CircFndc3b modulates cardiac repair after myocardial infarction via FUS/VEGF-A axis. Nat. Commun. 10, 4317–4317 (2019).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  12. Ye, Z. et al. The differential expression of novel circular RNAs in an acute lung injury rat model caused by smoke inhalation. J. Physiol. Biochem. 74, 25–33 (2018).

    CAS  PubMed  Article  Google Scholar 

  13. Li, X. et al. Microarray analysis reveals the changes of circular RNA expression and molecular mechanism in acute lung injury mouse model. J. Cell. Biochem. 120, 16658–16667 (2019).

    CAS  PubMed  Article  Google Scholar 

  14. Zhou, Z. et al. circRNA mediates silica-induced macrophage activation via HECTD1/ZC3H12A-dependent ubiquitination. Theranostics 8, 575–592 (2018).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  15. Cai, J. et al. circHECTD1 facilitates glutaminolysis to promote gastric cancer progression by targeting miR-1256 and activating β-catenin/c-Myc signaling. Cell Death Dis. 10, 576–576 (2019).

    PubMed  PubMed Central  Article  Google Scholar 

  16. Peng, X., Jing, P., Chen, J. & Xu, L. The role of circular RNA HECTD1 expression in disease risk, disease severity, inflammation, and recurrence of acute ischemic stroke. J. Clin. Lab. Anal. 33, e22954–e22954 (2019).

    CAS  PubMed  PubMed Central  Google Scholar 

  17. Li, X., Yang, L. & Chen, L.-L. The biogenesis, functions, and challenges of circular RNAs. Mol. Cell 71, 428–442 (2018).

    CAS  PubMed  Article  Google Scholar 

  18. Han, B., Chao, J. & Yao, H. Circular RNA and its mechanisms in disease: From the bench to the clinic. Pharmacol. Ther. 187, 31–44 (2018).

    CAS  PubMed  Article  Google Scholar 

  19. Bi, J. et al. Circ-BPTF promotes bladder cancer progression and recurrence through the miR-31-5p/RAB27A axis. Aging (Albany NY) 10, 1964–1976 (2018).

    CAS  Article  Google Scholar 

  20. Wei, S. et al. The circRNA circPTPRA suppresses epithelial-mesenchymal transitioning and metastasis of NSCLC cells by sponging miR-96-5p. EBioMedicine 44, 182–193 (2019).

    PubMed  PubMed Central  Article  Google Scholar 

  21. Han, B. et al. Novel insight into circular RNA HECTD1 in astrocyte activation via autophagy by targeting MIR142-TIPARP: implications for cerebral ischemic stroke. Autophagy 14, 1164–1184 (2018).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  22. Xie, W. et al. miR-34b-5p inhibition attenuates lung inflammation and apoptosis in an LPS-induced acute lung injury mouse model by targeting progranulin. J. Cell. Physiol. 233, 6615–6631 (2018).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  23. Dunn, K. W., Kamocka, M. M. & McDonald, J. H. A practical guide to evaluating colocalization in biological microscopy. American J. Physiol. Cell Physiol. 300, C723–C742 (2011).

    CAS  Article  Google Scholar 

  24. Yang, J. et al. Circular RNA hsa_circRNA_0007334 is predicted to promote MMP7 and COL1A1 expression by functioning as a miRNA sponge in pancreatic ductal adenocarcinoma. J. Oncol. 2019, 7630894–7630894 (2019).

    PubMed  PubMed Central  Google Scholar 

  25. Shen, S. et al. CircSERPINE2 protects against osteoarthritis by targeting miR-1271 and ETS-related gene. Ann. Rheum. Dis. 78, 826–836 (2019).

    CAS  PubMed  Article  Google Scholar 

  26. Wang, X.-B. et al. circRNA_0006393 promotes osteogenesis in glucocorticoid‑induced osteoporosis by sponging miR‑145‑5p and upregulating FOXO1. Mol. Med. Rep. 20, 2851–2858 (2019).

    CAS  PubMed  Google Scholar 

  27. Cheng, Y. et al. CircRNA-012091/PPP1R13B-mediated Lung Fibrotic Response in Silicosis via Endoplasmic Reticulum Stress and Autophagy. Am. J. Respir. Cell Mol. Biol. 61, 380–391 (2019).

    CAS  PubMed  Article  Google Scholar 

  28. Fang, S. et al. circHECTD1 promotes the silica-induced pulmonary endothelial-mesenchymal transition via HECTD1. Cell Death Dis. 9, 396–396 (2018).

    PubMed  PubMed Central  Article  Google Scholar 

  29. Cao, J. & Liu, X.-S. Circular RNA 0060428 sponges miR-375 to promote osteosarcoma cell proliferation by upregulating the expression of RPBJ. Gene. 740, 144520–144520 (2020).

    CAS  PubMed  Article  Google Scholar 

  30. Xiang, Q. et al. CircRNA-CIDN mitigated compression loading-induced damage in human nucleus pulposus cells via miR-34a-5p/SIRT1 axis. EBioMedicine 53, 102679–102679 (2020).

    PubMed  PubMed Central  Article  Google Scholar 

  31. Janku, F. et al. Assessing PIK3CA and PTEN in early-phase trials with PI3K/AKT/mTOR inhibitors. Cell Rep. 6, 377–387 (2014).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  32. Bao, S. et al. Keratinocyte growth factor induces Akt kinase activity and inhibits Fas-mediated apoptosis in A549 lung epithelial cells. Am. J. Physiol. Lung Cell Mol. Physiol. 288, L36–L42 (2005).

    CAS  PubMed  Article  Google Scholar 

  33. Ke, X.-F., Fang, J., Wu, X.-N. & Yu, C.-H. MicroRNA-203 accelerates apoptosis in LPS-stimulated alveolar epithelial cells by targeting PIK3CA. Biochem. Biophys. Res. Commun. 450, 1297–1303 (2014).

    CAS  PubMed  Article  Google Scholar 

  34. Zhou, L. et al. Overexpression of SIRT1 prevents hypoxia‑induced apoptosis in osteoblast cells. Mol. Med. Rep. 16, 2969–2975 (2017).

    PubMed  Article  Google Scholar 

  35. Mu, W. et al. Overexpression of a dominant-negative mutant of SIRT1 in mouse heart causes cardiomyocyte apoptosis and early-onset heart failure. Sci. China Life Sci. 57, 915–924 (2014).

    CAS  PubMed  Article  Google Scholar 

  36. Peng, X.-P., Li, X.-H., Li, Y., Huang, X.-T. & Luo, Z.-Q. The protective effect of oleanolic acid on NMDA-induced MLE-12 cells apoptosis and lung injury in mice by activating SIRT1 and reducing NF-κB acetylation. Int. Immunopharmacol. 70, 520–529 (2019).

    CAS  PubMed  Article  Google Scholar 

  37. Liu, X., Shao, K. & Sun, T. SIRT1 regulates the human alveolar epithelial A549 cell apoptosis induced by Pseudomonas aeruginosa lipopolysaccharide. Cell Physiol. Biochem. 31, 92–101 (2013).

    PubMed  Article  Google Scholar 

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This study was supported by the finding of the Key scientific research projects of henan provincial colleges and universities (NO. 19A320009).

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Authors and Affiliations



L.H.B. and G.M. participated in the experimental design, manuscript writing and manuscript revision. L.H.B., N.X.X., S.H.J., F.M., D.Y.M., S.R.Q., and M.N.L. participated in cell experiments, acquisition of data, data analysis and interpretation. W.H.L. and W.D. participated in animal experiment and histological experiment. All authors read, revised, and approved the final manuscript.

Corresponding authors

Correspondence to Hongbin Li or Min Gao.

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The authors declare no competing interests.

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The animal experiments were performed in the Laboratory Animal Center of Zhengzhou University and approved by the Animal Ethics Committee of the First Affiliated Hospital of Zhengzhou University.

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Li, H., Niu, X., Shi, H. et al. circHECTD1 attenuates apoptosis of alveolar epithelial cells in acute lung injury. Lab Invest 102, 945–956 (2022).

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