Lipocalin 2 activates the NLRP3 inflammasome via LPS‑induced NF‑κB signaling and plays a role as a pro‑inflammatory regulator in murine macrophages

Lipocalin 2 (LCN2) is highly expressed in several infectious and inflammatory disorders. However, the expression level and underlying mechanism of LCN2 in inflammatory bowel disease (IBD) are poorly understood. The current study used murine IBD models and LPS-activated macrophages to elucidate the role of LCN2 in IBD pathogenesis. The levels of LCN2 protein and concentration were confirmed to be much higher in the colons of colitis-induced mice compared with healthy mice using immunohistochemistry, western blotting and ELISA assay. In vitro, the level of LCN2 in RAW264.7 macrophages increased significantly following LPS stimulation and diminished markedly upon using NF-κB-specific inhibitors. Assembly of the NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome was inhibited when LCN2 expression was knocked down, as evidenced by decreased NLRP3, ASC-1 and caspase-1 activation. Furthermore, secretion and maturation of IL-1β was attenuated when LCN2 was silenced in LPS-stimulated macrophages. Together, these results suggested that LCN2 directly upregulated the NLRP3 inflammasome complex via NF-κB activation in response to stimulating macrophages with LPS, and that it acted as a pro-inflammatory regulator in macrophage activation modulated by NF-κB activation. Overall, LCN2 may serve as a promising target for the prevention and treatment of IBD.

Effects of boric acid and potassium metaborate on cytokine levels and redox stress parameters in a wound model infected with methicillin‑resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) infections are usually found in hospital settings and, frequently, in patients with open wounds. One of the most critical virulence factors affecting the severity and recurrence of infections is the biofilm; increasing antibiotic resistance due to biofilm formation has led to the search for alternative compounds to antibiotics. The present study aimed to use boric acid and potassium metaborate against MRSA infection in a fibroblast wound model. For this purpose, a two-part experiment was designed: First, MRSA strains were used for the test, and both boric acid and potassium metaborate were prepared in microdilution. In the second step, an MRSA wound model was prepared using a fibroblast culture, and treatments with boric acid and potassium metaborate were applied for 24 h. For the evaluation of the effects of treatment, cell viability assay (MTT assay), analysis of redox stress parameters, including total oxidant status and total antioxidant capacity analyses, lactate dehydrogenase analysis and immunohistochemical staining were performed. In addition, IL-1β and IL-10 gene expression levels were assayed. According to the results, potassium metaborate was more effective and exhibited a lower toxicity to fibroblast cells compared to boric acid; moreover, potassium metaborate decreased the level of prooxidant species and increased the antioxidant status more effectively than boric acid. The IL-1β level in the bacteria group was high; however, boric acid and potassium metaborate significantly decreased the expression levels of inflammatory markers, exhibiting the potential to improve the resolution of the lesion. On the whole, the findings of the present study suggest that boric acid and potassium metaborate may be effective on the tested microorganisms.

IL‑1β‑induced pentraxin 3 inhibits the proliferation, invasion and cell cycle of trophoblasts in preeclampsia and is suppressed by IL‑1β antagonists

Pentraxin 3 (PTX3), a member of the c‑reactive protein family, is a long pentraxin protein and a pro‑inflammatory marker. However, the role of PTX3 in preeclampsia (PE) remains to be elucidated. Thus, the present study aimed to investigate the biological role and mechanisms underlying PTX3 in PE. In the present study, PTX3 was overexpressed in trophoblasts and the subsequent changes in cell proliferation, cycle distribution and invasion were observed using Cell Counting Kit‑8, flow cytometry and Transwell assays, respectively. Moreover, the expression levels of MMP2 and MMP9, proteins associated with the development of PE, were detected using reverse transcription‑quantitative PCR and western blot analysis. Following treatment with interleukin (IL)‑1β, the expression levels of PTX3 were measured. Furthermore, subsequent changes in cell proliferation, cycle distribution and invasion were investigated following overexpression of PTX3 and treatment with IL‑1 receptor antagonist (IL‑1Ra). Overexpression of PTX3 inhibited the proliferation, cycle and invasion of HTR‑8/SV neo and JEG3 cells. Moreover, treatment with IL‑1β increased the expression of PTX3 in HTR‑8/SV neo and JEG3 cells, which was suppressed following treatment with the IL‑1β antagonist. Following PTX3 overexpression and treatment with IL‑1Ra, the inhibitory effects of PTX3 overexpression alone on the invasion of HTR‑8/SV neo and JEG3 cells were attenuated. In conclusion, these results indicated that IL‑1β could induce PTX3 upregulation, which led to the inhibition of the proliferation, invasion and cell cycle of trophoblasts, thereby promoting the progression of PE.

Simiaosan alleviates the symptoms of gouty arthritis via the NALP3/IL‑1β pathway

Previous studies have suggested that the herbal medicine simiaosan has beneficial effects on gouty arthritis (GA), for which conventional Western medicines are insufficient (particularly in cases of multiple episodes). The objective of the present study was to investigate the mechanism by which simiaosan alleviated the symptoms of GA. Sprague-Dawley rat models of acute GA were successfully established, as verified by pathological analyses. Additionally, an NLR family pyrin domain containing 3 (NLRP3) overexpression vector was constructed and a high transfection efficiency was confirmed by reverse transcription PCR. The following five treatment groups were established: i) Normal control; ii) model + saline; iii) model + simiaosan; iv) model + NALP3-overexpressing adenovirus + simiaosan; and v) model + empty vector adenovirus + simiaosan. The samples from mice in each group were subjected to hematoxylin and eosin (H&E) staining for assessing the histopathological changes, enzyme-linked immunosorbent assays for determining IL-1β and TGF-β1 levels and western blotting for evaluating NALP3 expression. H&E staining indicated that simiaosan could reduce the infiltration of inflammatory cells, while NALP3 overexpression aggravated the inflammatory response in tissues. Expression levels of IL-1β, TGF-β1 and NALP3 were significantly higher in the model and the model + NALP3-overexpressing adenovirus + simiaosan groups compared with the normal control group. Levels of IL-1β, TGF-β1 and NALP3 were significantly lower in the model + simiaosan and model + empty vector adenovirus + simiaosan groups compared with the model group. These results indicated that the effects of simiaosan were mediated through NALP3 inhibition. Therefore, the herbal medicine simiaosan was revealed to possess an ability to alleviate the symptoms of GA by regulating the NALP3/IL-1β signaling pathway.