NFκB promotes oxidative stress-induced necrosis and ischemia/reperfusion injury by inhibiting Nrf2-ARE pathway

Xiaoyun Guo1, Siqi Hong1, Hui He1

  • 1Department of Physiology and Biophysics, University of Washington, Seattle, WA, 98195, USA.

Insights

Nuclear Factor kappa B (NFκB) promotes cell death during oxidative stress by suppressing antioxidant pathways. Inhibiting NFκB protects against heart injury and improves cardiac function after ischemia.

Area of Science:

  • Molecular Biology
  • Cardiovascular Research
  • Cell Death Mechanisms

Background:

  • Oxidative stress is a key factor in cell death and organ injury, particularly in the heart.
  • Nuclear Factor kappa B (NFκB) is a transcription factor typically associated with inflammation and survival, but its role in oxidative stress-induced cell death is complex.
  • The Nrf2-ARE pathway is crucial for cellular defense against oxidative damage.

Purpose of the Study:

  • To investigate the role of NFκB in oxidative stress-induced necrosis.
  • To elucidate the mechanism by which NFκB influences antioxidant signaling.
  • To evaluate the therapeutic potential of targeting NFκB in cardiac ischemic injury.

Main Methods:

  • Utilized genetic manipulation (e.g., NFκB-p65 inactivation, cardiomyocyte-specific deletion) and pharmacological inhibitors (e.g., BMS-345541, trichostatin A).
  • Assessed cell death, HMGB1 release, and NFκB-luciferase activity in cardiomyocytes under simulated ischemia/reperfusion (sI/R) and doxorubicin (DOX) treatment.
  • Investigated protein interactions (co-immunoprecipitation) and transcriptional activity of Nrf2-ARE.
  • Evaluated myocardial infarct size, cardiac remodeling, and functional recovery in vivo after ischemia/reperfusion (I/R) injury.

Main Results:

  • NFκB activation promoted, while its inactivation inhibited, oxidative stress-induced cell death and HMGB1 release.
  • NFκB suppressed Nrf2-ARE antioxidant signaling and reduced the expression of antioxidant proteins via transcriptional silencing, dependent on HDAC3 interaction.
  • Inhibition of NFκB or HDAC3 enhanced Nrf2-ARE activity and promoted cell survival post-sI/R.
  • Cardiomyocyte-specific deletion of NFκB-p65 attenuated myocardial infarct size and improved cardiac function and remodeling after I/R injury.

Conclusions:

  • NFκB acts as a pro-cell death factor in oxidative stress-induced necrosis by suppressing the Nrf2-ARE antioxidant pathway through an HDAC3-dependent mechanism.
  • Targeting NFκB represents a novel therapeutic strategy for mitigating cardiac ischemic injury and pathological remodeling.

Related Concept Videos

NF-κB-dependent Signaling Pathway02:26

NF-κB-dependent Signaling Pathway

The transcription factor NF-κB was discovered in 1986 in the lab of Nobel laureate Professor David Baltimore, for its interaction with the immunoglobulin light chain enhancer in B-cells. After more than three decades of study, it is now evident that NF-κB regulates the expression of over 100 genes. Most of these genes play an essential role in the innate and adaptive immune responses as well as the inflammatory responses of animals.
NF-κB-dependent Signaling Mechanism
The...
9.6K
Necrosis01:16

Necrosis

Necrosis is considered as an “accidental” or unexpected form of cell death that ends in cell lysis. The first noticeable mention of “necrosis” was in 1859 when Rudolf Virchow used this term to describe advanced tissue breakdown in his compilation titled “Cell Pathology”.
Morphological Manifestations of Necrosis
Necrotic cells show different types of morphological appearance depending on the type of tissue and infection. In coagulative necrosis, cells become...
5.9K
The Extrinsic Apoptotic Pathway01:17

The Extrinsic Apoptotic Pathway

The extrinsic apoptotic pathway is initiated when extracellular death-inducing signals, such as specific cytokines, activate the death receptors expressed on the cell surface. The immune cells involved in this pathway are natural killer cells (NK cells) and cytotoxic T-lymphocytes. NK cells are critical in innate immune response, while cytotoxic T-lymphocytes are associated with adaptive immune response. These cells recognize specific receptors expressed on the altered cells and activate...
7.7K
The Intrinsic Apoptotic Pathway01:31

The Intrinsic Apoptotic Pathway

Internal cellular stress, such as cellular injury or hypoxia, triggers intrinsic apoptosis. The B-cell lymphoma 2 (Bcl-2) family of proteins are the primary regulators of the intrinsic apoptotic pathway. For example, during DNA damage, checkpoint proteins, such as Ataxia Telangiectasia Mutated (ATM protein) and Checkpoints Factor-2 (Chk2) proteins, are activated. These proteins phosphorylate p53 which further activates pro-apoptotic proteins, such as Bax, Bak, PUMA, and Noxa, and inhibits...
7.9K
MAPK Signaling Cascades01:07

MAPK Signaling Cascades

Mitogen-activated protein kinase, or MAPK pathway, activates three sequential kinases to regulate cellular responses such as proliferation, differentiation, survival, and apoptosis. The canonical MAPK pathway starts with a mitogen or growth factor binding to an RTK. The activated RTKs stimulate Ras, which recruits Raf or MAP3 Kinase (MAPKKK), the first kinase of the MAPK signaling cascade. Raf further phosphorylates and activates MEK or MAP2 Kinases (MAPKK), which in turn phosphorylates MAP...
7.6K
Co-activators and Co-repressors02:04

Co-activators and Co-repressors

Gene transcription is regulated by the synergistic action of several proteins that form a complex at a gene regulatory site. This is observed in eukaryotes, where the regulation of gene expression is a complex process. Regulatory proteins in eukaryotes can broadly be classified into two types – regulators that bind directly to specific DNA sequences and co-regulators that associate with regulatory proteins but cannot directly bind to the DNA. These co-regulators are further divided into...
8.2K