Nr4A1 modulates inflammation-associated intestinal fibrosis and dampens fibrogenic signaling in myofibroblasts

Abstract

Background: Intestinal fibrosis is a common complication of the inflammatory bowel diseases(IBD), contributing to tissue stiffening and luminal narrowing. NR4A1 was previously reported to regulate mesenchymal cell function and dampen fibrogenic signaling. NR4A1 gene variants are associated with IBD risk, and it has been shown to regulate intestinal inflammation. Here, we tested the hypothesis that NR4A1 acts as a negative regulator of intestinal fibrosis through regulating myofibroblast function. Methods: Using the SAMP1/YitFc mouse, we tested whether two pharmacological agents known to enhance NR4A1 signaling: cytosporone B(Csn-B) or 6-mercaptopurine(6-MP); could reduce fibrosis. We also employed the dextran sulphate sodium(DSS) model of colitis and assessed the magnitude of colonic fibrosis in Nr4a1-/- and their wild-type littermates(Nr4a1+/+). Lastly, intestinal myofibroblasts isolated from Nr4a1-/- and Nr4a1+/+ mice or primary human intestinal myofibroblasts were stimulated with transforming growth factor-beta-1(TGF-β1), in the presence or absence of Csn-B or 6-MP, and proliferation and ECM gene expression assessed. Results: Csn-B or 6-MP treatment significantly reduced ileal thickness, collagen and overall ECM content in SAMP1/YitFc mice. This was associated with a reduction in proliferative markers within the mesenchymal compartment. Nr4a1-/- mice exposed to DSS exhibited increased colonic thickening and ECM content. Nr4a1-/- myofibroblasts displayed enhanced TGF-β1-induced proliferation. Furthermore, Csn-B or 6-MP treatment was anti-proliferative in Nr4a1+/+, but not Nr4a1-/- cells. Lastly, activating NR4A1 in human myofibroblasts reduced TGF-β1-induced collagen deposition and fibrosis-related gene expression. Conclusions: Our data suggest that NR4A1 can attenuate fibrotic processes in intestinal myofibroblasts and could provide a valuable clinical target to treat inflammation-associated intestinal fibrosis.

The nuclear receptor NR4A1 restrains neutrophil granulocyte mediated brain damage in cerebral ischemia

“…Stroke induces a substantial inflammatory response within the CNS parenchyma accompanied by activation of brain resident immune cells and infiltration of hematogenous immune cells (Beuker et al, 2021). As the nuclear receptor NR4A1 has been shown to play a central role in various pathophysiological immune-mediated processes (Koenis et al, 2018; Pulakazhi et al, 2021), we have hypothesized that NR4A1 may also play a role during the progression of immune-mediated post-ischemic brain damage. As a first step, we evaluated Nr4a1-mRNA and NR4A1-protein expression after middle cerebral artery occlusion (MCAO) in C57BL/6 mice (30 min MCAO) over a time-course of 7 days post ischemia.…”

The Impact of Aging on the Lung Alveolar Environment, Predetermining Susceptibility to Respiratory Infections

“…Studies using human and murine macrophages ( Zollner and Trauner, 2009 ; Dhiman et al, 2018 ; Leopold Wager et al, 2019a ; Leopold Wager et al, 2019b ; Ning et al, 2019 ; Zhao et al, 2019 ; Zhao et al, 2020 ) in cancer ( Zhou et al, 2014 ; Dhiman et al, 2018 ; Zhao et al, 2019 ), auto-immunity ( Zollner and Trauner, 2009 ; Lee et al, 2011 ; Ning et al, 2019 ; Olson et al, 2020 ) and infectious diseases ( Renga et al, 2012 ; Leopold Wager et al, 2019a ; Leopold Wager et al, 2019b ) have highlighted the importance of NRs in maintaining tissue homeostasis ( Nagy et al, 2013 ; Zhao et al, 2020 ; Alatshan and Benkő, 2021 ). Several NRs are postulated to dampen pro-inflammatory networks ( De Bosscher et al, 2006 ; Huang and Glass, 2010 ; Mandard and Patsouris, 2013 ; Li et al, 2015 ; Wang et al, 2017 ; Duez and Pourcet, 2021 ; Pulakazhi Venu et al, 2021 ; Vuttaradhi et al, 2021 ). Thus, NR dysfunction during aging may remove the brakes to pro-inflammatory and oxidative stress pathways with associated altered mitochondrial function as discussed above.…”

Intestinal strictures in Crohn’s disease: a 2021 update

“…Molecules act as the mediators of cells and play a key role in intestinal fibrosis. 21 In the year 2021, several novel molecules have been discovered and are considered as new therapeutic targets for intestinal fibrosis, including Yes-associated protein and transcriptional coactivator with PDZ-binding motif (YAP/TAZ), 22 tumor necrosis factor-like ligand 1A (TL1A), 23 anterior gradient protein 2 homolog (AGR2), 24 pH-sensing G protein-coupled receptor 4 (GPR4), 25 miR-155, 26 human nuclear receptor 4A 1 (NR4A1), 27 and vitamin D receptor (VDR). 28 …”

“…In contrast to the aforementioned molecules that have profibrotic property, NR4A1 can dampen fibrogenic signaling in nonintestinal systems, and protect against fibrosis. 32 Pulakazhi Venu et al 27 added new evidence to support the antifibrotic effect of NR4A1 in intestine system using a Crohn’s-like ileitis murine model. They demonstrated that pharmacological activation of NR4A1 with cytosporone B or 6-mercaptopurine could decrease the deposition of ECM and proliferation of myofibroblasts, ultimately preventing fibrosis.…”

“…Besides, NR4A1 activation was found to be able to attenuate TGF-β1-induced proliferation, collagen production, and fibrogenic gene expression in human intestinal fibroblasts [ Figure 2(d) ]. 27 Similarly, VDR activation or VD supplement also contributed to alleviating intestinal fibrosis. 28 …”