NF-κB inhibition compromises cardiac fibroblast viability under hypoxia

M. Sangeetha, Malini S. Pillai, Linda Philip, Edward G. Lakatta, K. Shivakumar

Research output: Contribution to journalArticlepeer-review

Abstract

Cardiac fibroblasts are reported to be relatively resistant to stress stimuli compared to cardiac myocytes and fibroblasts of non-cardiac origin. However, the mechanisms that facilitate their survival under conditions of stress remain unclear. We explored the possibility that NF-κB protects cardiac fibroblasts from hypoxia-induced cell death. Further, we examined the expression of the antiapoptotic cIAP-2 and Bcl-2 in hypoxic cardiac fibroblasts, and their possible regulation by NF-κB. Phase contrast microscopy and propidium iodide staining revealed that cardiac fibroblasts are more resistant than pulmonary fibroblasts to hypoxia. Electrophoretic Mobility Shift Assay showed that hypoxia activates NF-κB in cardiac fibroblasts. Supershift assay indicated that the active NF-κB complex is a p65/p50 heterodimer. An I-κB-super-repressor was constructed that prevented NF-κB activation and compromised cell viability under hypoxic but not normoxic conditions. Similar results were obtained with Bay 11-7085, an inhibitor of NF-κB. Western blot analysis showed constitutive levels of Bcl-2 and hypoxic induction of cIAP-2 in these cells. NF-κB inhibition reduced cIAP-2 but not Bcl-2 levels in hypoxic cardiac fibroblasts. The results show for the first time that NF-κB is an important effector of survival in cardiac fibroblasts under hypoxic stress and that regulation of cIAP-2 expression may contribute to its pro-survival role.

Original languageEnglish (US)
Pages (from-to)899-909
Number of pages11
JournalExperimental cell research
Volume317
Issue number7
DOIs
StatePublished - Apr 15 2011

Keywords

  • Bcl-2
  • CIAP-2
  • Cardiac fibroblasts
  • Cell survival
  • Hypoxia
  • NF-κB

ASJC Scopus subject areas

  • Cell Biology

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