Dataset Information

Short Chain Fatty Acid Acetate Increases TNFα-Induced MCP-1 Production in Monocytic Cells via ACSL1/MAPK/NF-κB Axis.

ABSTRACT: Short-chain fatty acid (SCFA) acetate, a byproduct of dietary fiber metabolism by gut bacteria, has multiple immunomodulatory functions. The anti-inflammatory role of acetate is well documented; however, its effect on monocyte chemoattractant protein-1 (MCP-1) production is unknown. Similarly, the comparative effect of SCFA on MCP-1 expression in monocytes and macrophages remains unclear. We investigated whether acetate modulates TNFα-mediated MCP-1/CCL2 production in monocytes/macrophages and, if so, by which mechanism(s). Monocytic cells were exposed to acetate with/without TNFα for 24 h, and MCP-1 expression was measured. Monocytes treated with acetate in combination with TNFα resulted in significantly greater MCP-1 production compared to TNFα treatment alone, indicating a synergistic effect. On the contrary, treatment with acetate in combination with TNFα suppressed MCP-1 production in macrophages. The synergistic upregulation of MCP-1 was mediated through the activation of long-chain fatty acyl-CoA synthetase 1 (ACSL1). However, the inhibition of other bioactive lipid enzymes [carnitine palmitoyltransferase I (CPT I) or serine palmitoyltransferase (SPT)] did not affect this synergy. Moreover, MCP-1 expression was significantly reduced by the inhibition of p38 MAPK, ERK1/2, and NF-κB signaling. The inhibition of ACSL1 attenuated the acetate/TNFα-mediated phosphorylation of p38 MAPK, ERK1/2, and NF-κB. Increased NF-κB/AP-1 activity, resulting from acetate/TNFα co-stimulation, was decreased by ACSL1 inhibition. In conclusion, this study demonstrates the proinflammatory effects of acetate on TNF-α-mediated MCP-1 production via the ACSL1/MAPK/NF-κB axis in monocytic cells, while a paradoxical effect was observed in THP-1-derived macrophages.

SUBMITTER: Al-Roub A

PROVIDER: S-EPMC8304091 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:The sodium-iodide symporter (NIS) mediates transport of iodide across the basolateral membrane of thyroid cells. NIS expression in thyroid cancer (TC) cells allows the use of radioactive iodine (RAI) as a diagnostic and therapeutic tool, being RAI therapy the systemic treatment of choice for metastatic disease. Still, a significant proportion of patients with advanced TC lose the ability to respond to RAI therapy and no effective alternative therapies are available. Defective NIS expression is the main reason for impaired iodide uptake in TC and NIS downregulation has been associated with several pathways linked to malignant transformation. NF-κB signaling is one of the pathways associated with TC. Interestingly, NIS expression can be negatively regulated by TNF-α, a bona fide activator of NF-κB with a central role in thyroid autoimmunity. This prompted us to clarify NF-kB's role in this process. We confirmed that TNF-α leads to downregulation of TSH-induced NIS expression in non-neoplastic thyroid follicular cell-derived models. Notably, a similar effect was observed when NF-κB activation was triggered independently of ligand-receptor specificity, using phorbol-myristate-acetate (PMA). TNF-α and PMA downregulation of NIS expression was reverted when NF-κB-dependent transcription was blocked, demonstrating the requirement for NF-kB activity. Additionally, TNF-α and PMA were shown to have a negative impact on TSH-induced iodide uptake, consistent with the observed transcriptional downregulation of NIS. Our data support the involvement of NF-κB-directed transcription in the modulation of NIS expression, where up- or down-regulation of NIS depends on the combined output to NF-κB of several converging pathways. A better understanding of the mechanisms underlying NIS expression in the context of normal thyroid physiology may guide the development of pharmacological strategies to increase the efficiency of iodide uptake. Such strategies would be extremely useful in improving the response to RAI therapy in refractory-TC.

Project description:Background & aimsThe progression of hepatosteatosis to non-alcoholic steatohepatitis (NASH) is a critical step in the pathogenesis of hepatocellular cancer. However, the underlying mechanism(s) for this progression is essentially unknown. This study was designed to determine the role of miR-378 in regulating NASH progression.MethodsWe used immunohistochemistry, luciferase assays and immunoblotting to study the role of miR-378 in modulating an inflammatory pathway. Wild-type mice kept on a high-fat diet (HFD) were injected with miR-378 inhibitors or a mini-circle expression system containing miR-378, to study loss and gain-of functions of miR-378.ResultsMiR-378 expression is increased in livers of dietary obese mice and patients with NASH. Further studies revealed that miR-378 directly targeted Prkag2 that encodes AMP-activated protein kinase γ 2 (AMPKγ2). AMPK signaling negatively regulates the NF-κB-TNFα inflammatory axis by increasing deacetylase activity of sirtuin 1. By targeting Prkag2, miR-378 reduced sirtuin 1 activity and facilitated an inflammatory pathway involving NF-κB-TNFα. In contrast, miR-378 knockdown induced expression of Prkag2, increased sirtuin 1 activity and blocked the NF-κB-TNFα axis. Additionally, knockdown of increased Prkag2 offset the inhibitory effects of miR-378 inhibitor on the NF-κB-TNFα axis, suggesting that AMPK signaling mediates the role of miR-378 in facilitating this inflammatory pathway. Liver-specific expression of miR-378 triggered the development of NASH and fibrosis by activating TNFα signaling. Ablation of TNFα in miR-378-treated mice impaired the ability of miR-378 to facilitate hepatic inflammation and fibrosis, suggesting that TNFα signaling is required for miR-378 to promote NASH.ConclusionMiR-378 plays a key role in the development of hepatic inflammation and fibrosis by positively regulating the NF-κB-TNFα axis. MiR-378 is a potential therapeutic target for the treatment of NASH.Lay summaryThe recent epidemic of obesity has been associated with a sharp rise in the incidence of non-alcoholic fatty liver disease (NAFLD). However, the underlying mechanism(s) remains poorly described and effective therapeutic approaches against NAFLD are lacking. The results establish that microRNA-378 facilitates the development of hepatic inflammation and fibrosis and suggests the therapeutic potential of microRNA-378 inhibitor for the treatment of NAFLD.

Dataset Information

Short Chain Fatty Acid Acetate Increases TNFα-Induced MCP-1 Production in Monocytic Cells via ACSL1/MAPK/NF-κB Axis.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure