Transcription Factor NF‐κB: A Sensor for Smoke and Stress Signals

Abstract

Nuclear factor‐kappa B (NF‐κB) is a transcription factor that resides in the cytoplasm of every cell and translocates to the nucleus when activated. Its activation is induced by a wide variety of agents including stress, cigarette smoke, viruses, bacteria, inflammatory stimuli, cytokines, free radicals, carcinogens, tumor promoters, and endotoxins. On activation, NF‐κB regulates the expression of almost 400 different genes, which include enzymes (e.g., COX‐2, 5‐LOX, and iNOS), cytokines (such as TNF, IL‐1, IL‐6, IL‐8, and chemokines), adhesion molecules, cell cycle regulatory molecules, viral proteins, and angiogenic factors. The constitutive activation of NF‐κB has been linked with a wide variety of human diseases, including asthma, atherosclerosis, AIDS, rheumatoid arthritis, diabetes, osteoporosis, Alzheimer's disease, and cancer. Several agents are known to suppress NF‐κB activation, including Th2 cytokines (IL‐4, IL‐13, and IL‐10), interferons, endocrine hormones (LH, HCG, MSH, and GH), phytochemicals, corticosteroids, and immunosuppressive agents. Because of the strong link of NF‐κB with different stress signals, it has been called a “smoke‐sensor” of the body.