Ionizing radiation induces expression of interleukin 6 by human fibroblasts involving activation of nuclear factor-kappa B.

The proto-oncoprotein c-Rel is a member of the nuclear factor kappa B transcription factor family, which includes the p50 and p65 subunits of nuclear factor kappa B. We show here that c-Rel binds to kappa B sites as homodimers as well as heterodimers with p50. These homodimers and heterodimers show distinct DNA-binding specificities and affinities for various kappa B motifs. In particular, the c-Rel homodimer has a high affinity for interleukin-6 (IL-6) and beta interferon kappa B sites. In spite of its association with p50 in vitro, however, we found a lymphoid cell-specific nuclear factor in vivo that contains c-Rel but not p50 epitopes; this factor, termed IL-6 kappa B binding factor II, appears to contain the c-Rel homodimer and preferentially recognizes several IL-6 kappa B-related kappa B motifs. Although it has been previously shown that the IL-6 kappa B motif functions as a potent IL-1/tumor necrosis factor-responsive element in nonlymphoid cells, its activity was found to be repressed in lymphoid cells such as a Jurkat T-cell line. We also present evidence that IL-6 kappa B binding factor II functions as a repressor specific for IL-6 kappa B-related kappa B motifs in lymphoid cells.

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Abstract 15197: Lipopolysaccharide-Nuclear Factor-kappa B Pathway and Lipoprotein Apheresis Effects in Patients With Familial Hypercholesterolemia and Coronary Artery Disease

Circulation ◽

10.1161/circ.142.suppl_3.15197 ◽

2020 ◽

Vol 142 (Suppl_3) ◽

Author(s):

Huihui Liu ◽

Cheng-Gang Zhu ◽

Chuan-Jue Cui ◽

Yexuan Cao ◽

Jinglu Jin ◽

...

Keyword(s):

Coronary Artery Disease ◽

Coronary Artery ◽

Familial Hypercholesterolemia ◽

Interleukin 6 ◽

Nuclear Factor Kappa B ◽

Mononuclear Cells ◽

Nuclear Factor ◽

Lipoprotein Apheresis ◽

Nuclear Factor Kappa ◽

Artery Disease

Introduction: Inflammation may play an important role in atherosclerosis in familial hypercholesterolemia (FH). Lipopolysaccharide (LPS)-nuclear factor-kappa B (NF-κB) pathway is a routine signal process activated in inflammatory status. Hypothesis: We assessed the hypothesis that LPS-NF-κB axis is markedly activated and lipoprotein apheresis has an inhibitory effect on this pathway in patients with FH and coronary artery disease (CAD). Methods: In this matched case-control study a genetically diagnosed FH cohort who presented stable CAD (n=63) was compared with 63 non-FH CAD and 63 non-FH non-CAD controls matched by sex and age. Plasma LPS levels and NF-κB activity were compared among the three groups. In addition, we studied in vitro LPS-induced interleukin-6 production by mononuclear cells from 16 FH cases without previous statin use and compared them with their respective matched control groups. Subsequently, these 16 FH patients underwent lipoprotein apheresis. Blood samples were taken immediately before and regularly after apheresis for measuring LPS and NF-κB. Results: FH plus CAD had higher LPS levels and NF-κB activity than CAD and non-CAD controls (all p <0.01). LPS-induced interleukin-6 production by mononuclear cells of FH plus CAD was also much higher compared with CAD and non-CAD controls (both p <0.01). Moreover, plasma LPS levels ( p <0.001) and NF-κB activity ( p <0.01) were dramatically reduced after apheresis in FH patients. Conclusions: In conclusion, genetically confirmed FH patients with CAD had a marked activation of LPS-NF-κB axis, while lipoprotein apheresis significantly attenuated this key inflammatory pathway, suggesting that inflammation may be an important therapeutic target for FH patients.

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