High CO2 levels impair lung wound healing

Ankit Bharat*, Martin Angulo, Haiying Sun, Mahzad Akbarpour, Andres Alberro, Yuan Cheng, Masahiko Shigemura, Sergejs Berdnikovs, Lynn C. Welch, Jacob A. Kanter, G. R. Scott Budinger, Emilia Lecuona, Jacob I. Sznajder

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


Delayed lung repair leads to alveolopleural fistulae, which are a major cause of morbidity after lung resections. We have reported that intrapleural hypercapnia is associated with delayed lung repair after lung resection. Here, we provide new evidence that hypercapnia delays wound closure of both large airway and alveolar epithelial cell monolayers because of inhibition of epithelial cell migration. Cell migration and airway epithelial wound closure were dependent on Rac1-GTPase activation, which was suppressed by hypercapnia directly through the upregulation of AMP kinase and indirectly through inhibition of injury-induced NF-kB-mediated CXCL12 (pleural CXC motif chemokine 12) release, respectively. Both these pathways were independently suppressed, because dominant negative AMP kinase rescued the effects of hypercapnia on Rac1- GTPase in uninjured resting cells, whereas proteasomal inhibition reversed the NF-kB-mediated CXCL12 release during injury. Constitutive overexpression of Rac1-GTPase rescued the effects of hypercapnia on both pathways as well as on wound healing. Similarly, exogenous recombinant CXCL12 reversed the effects of hypercapnia through Rac1-GTPase activation by its receptor, CXCR4. Moreover, CXCL12 transgenic murine recipients of orthotopic tracheal transplantation were protected from hypercapnia-induced inhibition of tracheal epithelial cell migration and wound repair. In patients undergoing lobectomy, we found inverse correlation between intrapleural carbon dioxide and pleural CXCL12 levels as well as between CXCL12 levels and alveolopleural leak. Accordingly, we provide first evidence that high carbon dioxide levels impair lung repair by inhibiting epithelial cell migration through two distinct pathways, which can be restored by recombinant CXCL12.

Original languageEnglish (US)
Pages (from-to)244-254
Number of pages11
JournalAmerican journal of respiratory cell and molecular biology
Issue number2
StatePublished - Aug 2020


  • CXCL12
  • Hypercapnia
  • Rac1
  • Wound healing

ASJC Scopus subject areas

  • Molecular Biology
  • Pulmonary and Respiratory Medicine
  • Clinical Biochemistry
  • Cell Biology


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