Dataset Information

Activation of the alpha 7 nicotinic acetylcholine receptor mitigates osteoarthritis progression by inhibiting NF-κB/NLRP3 inflammasome activation and enhancing autophagy.

ABSTRACT: Osteoarthritis (OA) is a chronic degenerative joint disease characterized by cartilage degradation. Alpha 7 nicotinic acetylcholine receptor (α7nAChR) is associated with inflammatory and metabolic responses in OA. However, the mechanisms underlying the pathological process of OA remain unclear. The aim of the present study was to examine the role and mechanisms of α7nAChR-mediated autophagy and anti-inflammatory response in chondroprotection. Monosodium iodoacetate (MIA)-induced Wistar rat OA model was used to assess the in vivo effects of the ɑ7nAChR agonist (PNU-282987). The histopathological characteristics of OA were evaluated by immunohistochemistry (IHC), and the levels of autophagy markers were determined by western blotting and transmission electron microscopy. The anti-inflammatory effect of the ɑ7nAChR agonist was assessed by IHC, quantitative real-time polymerase chain reaction, and western blotting. Parallel experiments to determine the molecular mechanisms through which the ɑ7nAChR agonist prevents OA were performed using interleukin-1β (IL-1β)-treated chondrocytes. Our results showed that PNU-282987 reduced cartilage degeneration and matrix metalloproteinase (MMP)-1 and MMP-13 expressions. Activating α7nAChR with PNU-282987 significantly promoted MIA/IL-1β-induced chondrocyte autophagy, as demonstrated by the increase in LC3-II/LC3-I ratio, Beclin-1 levels, and autophagosome number. Furthermore, treating chondrocyte with ULK1 siRNA attenuated the PNU282987-induced enhancement of LC3-II/LC3-I ratio and Beclin-1 level. Additionally, PNU282987 suppressed NF-κB/NLRP3 inflammasome activation by inhibiting the ROS/TXNIP pathway and suppressed tumor necrosis factor-ɑ and IL-1β secretion in MIA/IL-1β-treated chondrocytes. Our results demonstrate that the activation of α7nAChR promotes chondrocyte autophagy and attenuates inflammation to mitigate OA progression, providing a novel target for the treatment of OA.

SUBMITTER: Zhu X

PROVIDER: S-EPMC8699641 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:Background: Inflammation and altered immunity contribute to the development of pulmonary arterial hypertension (PH). The alpha 7 nicotinic acetylcholine receptor (?7nAChR) possesses anti-inflammatory activities. The current study was performed to investigate the effects of a selective ?7nAChR agonist, PNU-282987, on controlling a monocrotaline (MCT)-induced rat model of PH and explored the underlying mechanisms. Methods: Sprague-Dawley rats were injected with MCT and treated with PNU-282987 at the prevention (starting 1 week before MCT) and treatment (starting 2 weeks after MCT) settings. Four weeks after MCT injection, hemodynamic changes, right ventricular structure, and lung morphological features were assessed. Enzyme-linked immunosorbent assay, Western blot and qRT-PCR were performed to assess levels of inflammatory cytokines and NLRP3 (Nod-like receptor family pyrin domain-containing 3) inflammasome pathway in the rat lung tissues. In addition, the lung macrophage line NR8383 was used to confirm the in vivo data. Results: Monocrotaline injection produced PH in rats and downregulated ?7nAChR mRNA and protein expression in rat lung tissues compared to sham controls. Pharmacological activation of ?7nAChR by PNU-282987 therapy improved the rat survival rate, attenuated the development of PH as assessed by remodeling of pulmonary arterioles, reduced the right ventricular (RV) systolic pressure, and ameliorated the hypertrophy and fibrosis of the RV in rats with MCT-induced PH. The expression of TNF-?, IL-6, IL-1?, and IL-18 were downregulated in rat lung tissues, which implied that PNU-282987 therapy may help regulate inflammation. These protective effects involved the inhibition of the NLRP3 inflammasome. In vitro assays of cultured rat lung macrophages confirmed that the anti-inflammation effect of PNU-282987 therapy may contribute to the disturbance of NLRP3 inflammasome activation. Conclusion: Targeting ?7nAChR with PNU-282987 could effectively prevent and treat PH with benefits for preventing ongoing inflammation in the lungs of rats with MCT-induced PH by inhibiting NLRP3 inflammasome activation.

Project description:BackgroundThe activation of NOD-like receptor protein 3 (NLRP3) inflammasome-dependent pyroptosis has been shown to play a vital role in the pathology of manganese (Mn)-induced neurotoxicity. Sodium para-aminosalicylic acid (PAS-Na) has a positive effect on the treatment of manganism. However, the mechanism is still unclear. We hypothesized that PAS-Na might act through NLRP3.MethodsThe microglial cell line BV2 and male Sprague-Dawley rats were used to investigate the impacts of PAS-Na on Mn-induced NLRP3 inflammasome-dependent pyroptosis. The related protein of the NF-κB pathway and NLRP3-inflammasome-dependent pyroptosis was detected by western blot. The reactive oxygen species and mitochondrial membrane potential were detected by immunofluorescence staining and flow cytometry. The activation of microglia and the gasdermin D (GSDMD) were detected by immunofluorescence staining.ResultsOur results showed that Mn treatment induced oxidative stress and activated the NF-κB pathway by increasing the phosphorylation of p65 and IkB-α in BV2 cells and in the basal ganglia of rats. PAS-Na could alleviate Mn-induced oxidative stress damage by inhibiting ROS generation, increasing mitochondrial membrane potential and ATP levels, thereby reducing the phosphorylation of p65 and IkB-α. Besides, Mn treatment could activate the NLRP3 pathway and promote the secretion of IL-18 and IL-1β, mediating pyroptosis in BV2 cells and in the basal ganglia and hippocampus of rats. But an inhibitor of NF-κb (JSH-23) treatment could significantly reduce LDH release, the expression of NLRP3 and Cleaved CASP1 protein and IL-1β and IL-18 mRNA level in BV2 cells. Interestingly, the effect of PAS-Na treatment in Mn-treated BV2 cells is similar to those of JSH-23. Besides, immunofluorescence results showed that PAS-Na reduced the increase number of activated microglia, which stained positively for GSDMD.ConclusionPAS-Na antagonized Mn-induced NLRP3 inflammasome dependent pyroptosis through inhibiting NF-κB pathway activation and oxidative stress.

Dataset Information

Activation of the alpha 7 nicotinic acetylcholine receptor mitigates osteoarthritis progression by inhibiting NF-κB/NLRP3 inflammasome activation and enhancing autophagy.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets