Macrophage-specific NF-κB activation dynamics can segregate inflammatory bowel disease patients

Abstract

The heterogeneous nature of inflammatory bowel disease (IBD) presents challenges, particularly when choosing therapy. Activation of the NF-B transcription factor is a highly-regulated, dynamic event in IBD pathogenesis. We expressed the human NF-B/p65 subunit in blood-derived macrophages, using lentivirus. Confocal imaging of p65 activation revealed that a higher proportion of macrophages from Crohn's patients responded to lipid-A compared to controls. In contrast, cells from ulcerative colitis (UC) patients exhibited a shorter duration of p65 nuclear localisation compared to healthy controls and Crohn's donors. Using a similar lentivirus approach, NF-B-regulated luciferase was expressed in patient macrophages, isolated from frozen peripheral blood mononuclear cell samples. Following activation, samples could be segregated into three clusters based on the NF-B-regulated luciferase response. The majority of UC samples appeared in hypo-responsive cluster 1, with Crohn's patients representing the majority of hyper-responsive cluster 3. A positive correlation was seen between NF-B-induced luciferase activity and cytokine levels released to medium from stimulated macrophages, but not in serum or biopsy. Analysis of macrophage cytokine responses and patient metadata revealed a strong correlation between Crohn's patients who smoked and hyperactivation of p65. These in vitro dynamic assays of NF-B activation in blood-derived macrophages segregate IBD patients into groups with different phenotypes and therefore may help determine response to therapy.

The association between transcriptional regulation of macrophage differentiation and activation and genetic susceptibility to inflammatory bowel disease

“…The analysis herein provides further strong support for the view that transcriptional dysregulation in macrophages has a causal relationship to IBD susceptibility. Based upon inducible expression of an NF-κB-regulated luciferase in patient macrophages in a cohort of similar size to ours, Papoutsopoulou et al [54] claimed that CD patients were hyper-responsive to TLR4 signalling. In our data, the overall patterns of gene expression in stimulated macrophages clustered based upon time, reflecting the major changes induced by LPS, but there was no relationship with disease status (Figure 1B).…”

Using systems medicine to identify a therapeutic agent with potential for repurposing in Inflammatory Bowel Disease

“…In conclusion, our findings strongly suggest that clarithromycin may be a viable, novel, anti-inflammatory therapeutic agent for IBD. In order to progress to a personalised medicine trial of clarithromycin in IBD a partner diagnostic test which can demonstrate altered NF-κB dynamics in patients’ peripheral blood monocyte derived macrophages is under development (35, 36), once established this will be used to inform a personalised drug repurposing trial for clarithromycin in IBD.…”

An unconventional role of an ASB family protein in NF-κB activation and inflammatory response during microbial infection and colitis

“…Chronic inflammatory bowel diseases (IBDs) are classified into two types: ulcerative colitis and Crohn's disease, which are characterized by chronic inflammatory responses in the immune system of the gut (43). It is well documented that the excessive activation of NF-κB and its downstream proinflammatory cytokines causes increased severity of IBD (44,45). Vice versa, inhibition of NF-κB can decrease inflammation and reduce the development of IBD (46).…”