Simvastatin inhibits NF-κB signaling in intestinal epithelial cells and ameliorates acute murine colitis
Introduction
Inflammatory bowel disease (IBD) (ulcerative colitis and Crohn's disease) is a chronic intestinal inflammatory disease characterized by tissue edema, increased gut epithelial permeability, and extensive infiltration of the gut by leukocytes [1], [2]. Although great advances have been made in the management of the disease with the introduction of immunomodulators and biologic agents, a curative therapy does not yet exist. Therefore, it is still challenging to develop novel specific therapies for IBD [3].
Recent studies have demonstrated increased production of proinflammatory cytokines including tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, and IL-8 in IBD that are known to play a key role in the modulation of intestinal immune system [4], [5], [6]. The nuclear transcription factor κB (NF-κB) is a key regulator of the inducible expression of numerous genes involved in immune and inflammatory responses in the gut [7], [8], [9]. Sustained activation of NF-κB is thought to be pivotal in the pathophysiology of chronic intestinal inflammation. Increased NF-κB activation has been detected in the intestinal lamina propria of patients with Crohn's disease [10], [11], and in a murine TNBS (trinitrobenzene sulphonic acid) colitis model [12]. Activation of this transcription factor then upregulates the expression of numerous proinflammatory genes involved in intestinal inflammation. Growing evidence in the association of NF-κB activation and IBD suggests that the modulation of NF-κB signaling pathway could be the main target for the anti-inflammatory treatment of IBD [8], [13].
Statins are a new class of anticholesteremic 3-hydroxy-3-methyl-glutaryl coenzyme A (HMG-CoA) reductase inhibitors and have several beneficial effects on the cardiovascular system not strictly related to their effects on cholesterol metabolism [14], [15], [16], [17], [18], [19], [20]. During the past several years these beneficial effects of statins have been identified which includes anti-inflammatory and immunomodulatory properties. Despite the increasing number of reports describing anti-inflammatory effects of statins, the molecular mechanisms of these effects remain to be elucidated. In every inflammatory process, the vast majority of cellular events require NF-κB transcriptional activity. Several studies have revealed that anti-inflammatory effects of statins are related to the modulation of NF-κB signaling pathway in vascular endothelial and smooth muscle cells, and monocytes [21], [22], [23], [24], [25], [26]. In addition, two studies reported that pravastatin [27] and rosuvastatin [28] reduced disease activity and colonic inflammation in dextran sulfate sodium (DSS)-induced colitis in mice. However, the anti-inflammatory mechanisms of statins on intestinal epithelial cells (IEC) and the experimental colitis still remain unknown.
Therefore, we aimed to investigate anti-inflammatory effects of simvastatin on IEC and on an experimental murine colitis model, and to elucidate its molecular mechanisms.
Section snippets
Cell culture and treatments
The human colon cancer cell line COLO 205 [KCLB 10222, Korean Cell Line Bank (KCLB), Seoul, Korea] was used between passages 15 and 30. Cells were grown as described previously [29], [30]. Simvastatin (MERCK and CO., Inc., Rahway, NJ, USA) was dissolved in ethanol and NaOH followed by neutralization to pH 7.2 for activation as a 10 mM stock solution and stored at − 20 °C. Cells were pretreated for 24 h with various concentrations of simvastatin (0–50 μM) or with vehicle, after which COLO 205
Simvastatin inhibited TNF-α-induced IL-8 mRNA expression and NF-κB transcriptional activity in IEC
We evaluated the effects of simvastatin on signal-induced IL-8 gene expression in IEC. As shown in Fig. 1A, simvastatin (50 μM) inhibited IL-8 mRNA expression at 1 h (49% inhibition) and 4 h (61% inhibition) post-stimulation in COLO 205 cells.
The transcription factor NF-κB is a down-stream signal effector pathway utilized by TNF-α. It also plays an essential role in signal-induced IL-8 gene expression in IEC [35]. We therefore sought to determine whether simvastatin prevents TNF-α-induced NF-κB
Discussion
The present study demonstrates, for the first time, anti-inflammatory effects of simvastatin on intestinal epithelial cells and elucidates the mechanisms involved. Statins have been shown to have anticholesteremic properties by inhibition of HMG-CoA reductase and have several beneficial effects on the cardiovascular system not strictly related to their effects on cholesterol metabolism. Statins inhibit interactions between leukocytes and endothelial cells; intravital microscopy confirms that
Acknowledgements
We wish to thank Hyeon Kyung Jeong for her excellent technical assistance. This work was supported by a grant from Seoul R&BD Program.
References (50)
Inflammatory bowel disease: etiology and pathogenesis
Gastroenterology
(1998)- et al.
Nuclear factor kappaB is activated in macrophages and epithelial cells of inflamed intestinal mucosa
Gastroenterology
(1998) - et al.
Statin drugs and dietary isoprenoids as antithrombotic agents
Hematol Oncol Clin North Am
(2000) - et al.
IKK beta and phosphatidylinositol 3-kinase/Akt participate in non-pathogenic Gram-negative enteric bacteria-induced RelA phosphorylation and NF-kappa B activation in both primary and intestinal epithelial cell lines
J Biol Chem
(2002) - et al.
Genome wide analysis of TNF-inducible genes reveals that antioxidant enzymes are induced by TNF and responsible for elimination of ROS
Mol Immunol
(2004) - et al.
Inhibition of NF-kappaB in cancer cells converts inflammation-induced tumor growth mediated by TNFalpha to TRAIL-mediated tumor regression
Cancer Cell
(2004) - et al.
IKKβ links inflammation and tumorigenesis in a mouse model of colitis-associated cancer
Cell
(2004) - et al.
Clarifying the causes of Crohn's
Nat Med
(1995) - et al.
State of the art: IBD therapy and clinical trials in IBD
Inflamm Bowel Dis
(2005) - et al.
Increased secretion of pro-inflammatory cytokines by circulating polymorphonuclear neutrophils and regulation by interleukin 10 during intestinal inflammation
Gut
(1998)
Regulatory cytokines in inflammatory bowel disease
Aliment Pharmacol Ther
A role for TNF-alpha and mucosal T helper-1 cytokines in the pathogenesis of Crohn's disease
J Immunol
The I kappa B/NF-kappa B system: a key determinant of mucosalinflammation and protection
Am J Physiol Cell Physiol
Role of NF-kappaB in immune and inflammatory responses in the gut
Gut
A role for transcription factor NF-κB in intestinal inflammation
Int J Colorectal Dis
Activation of nuclear factor kappa B inflammatory bowel disease
Gut
Local administration of antisense phosphorothioate oligonucleotides to the p65 subunit of NF-kappa B abrogates established experimental colitis in mice
Nat Med
NF-kappaB signaling proteins as therapeutic targets for inflammatory bowel diseases
Inflamm Bowel Dis
Randomised trial of cholesterol lowering in 4444 patients with coronary heart disease: the Scandinavian Simvastatin Survival Study (4S)
Lancet
Lescol Intervention Prevention Study (LIPS) Investigators. Fluvastatin for prevention of cardiac events following successful first percutaneous coronary intervention: a randomized controlled trial
JAMA
Mechanisms of action of statins and their pleiotropic effects
Ann Endocrinol (Paris)
Mevastatin, an HMG-CoA reductase inhibitor, reduces stroke damage and upregulates endothelial nitric oxide synthase in mice
Stroke
HMG-CoA reductase inhibitors: is the endothelium the main target?
Cardiology
Pleiotropic effects of 3-hydroxy-3-methylglutaryl coenzyme a reductase inhibitors
Arterioscler Thromb Vasc Biol
Statins differ in their ability to block NF-κB activation in human blood monocytes
Int J Clin Pharmacol Ther
Cited by (78)
Icosapent ethyl alleviates acetic acid-induced ulcerative colitis via modulation of SIRT1 signaling pathway in rats
2023, International ImmunopharmacologyStatins and inflammatory bowel disease: Where do we stand?
2020, European Journal of Internal MedicineRole of allopurinol and febuxostat in the amelioration of dextran-induced colitis in rats
2020, European Journal of Pharmaceutical SciencesEffect of Clostridium perfringens type C on TLR4/MyD88/NF-κB signaling pathway in piglet small intestines
2019, Microbial PathogenesisPotential mechanisms underlying the protective effects of salvianic acid A against atherosclerosis in vivo and vitro
2019, Biomedicine and Pharmacotherapy