Polypeptide from Moschus Suppresses Lipopolysaccharide-Induced Inflammation by Inhibiting NF-κB-ROS/NLRP3 Pathway

Objective: To examine the anti-inflammatory effects and potential mechanisms of polypeptide from Moschus(PPM) in lipopolysaccharide(LPS)-induced THP-1 macrophages and BALB/c mice. Methods:The polypeptide was extracted from Moschus and analyzed by high-performance liquid chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE). Subsequently, LPS was used to induce inflammation in THP-1 macrophages and BALB/c mice. In LPS-treated or untreated THP-1 macrophages, cell viability was observed by cell counting kit 8 and lactate dehydrogenase release assays; the proinflammatory cytokines and reactive oxygen species(ROS) were measured by enzyme-linked immunosorbent assay and flow cytometry, respectively; and protein and m RNA levels were measured by Western blot and real-time quantitative polymerase chain reaction(qRT-PCR), respectively. In LPS-induced BALB/c mice, the proinflammatory cytokines were measured, and lung histology and cytokines were observed by hematoxylin and eosin(HE) and immunohistochemical(IHC) staining, respectively. Results: The SDS-PAGE results suggested that the molecular weight of purified PPM was in the range of 10–26 k D. In vitro, PPM reduced the production of interleukin 1β(IL-1β),IL-18, tumor necrosis factor α(TNF-α), IL-6 and ROS in LPS-induced THP-1 macrophages(P<0.01). Western blot analysis demonstrated that PPM inhibited LPS-induced nuclear factor κB(NF-κB) pathway and thioredoxin interacting protein(TXNIP)/nucleotide-binding oligomerization domain, leucine-rich repeat and pyrin domain containing 3(NLRP3) inflammasome pathway by reducing protein expression of phospho-NF-κB p65, phosphoinhibitors of NF-κB(IκBs) kinase α/β(IKKα/β), TXNIP, NLRP3, apoptosis-associated speck-l ike protein containing a caspase recruitment domain(ASC), and pro-caspase-1(P<0.05 or P<0.01). In addition, q RT-PCR revealed the inhibitory effects of PPM on the m RNA levels of TXNIP, NLRP3, ASC, and caspase-1(P<0.05 or P<0.01). Furthermore, in LPS-induced BALB/c mice, PPM reduced TNF-α and IL-6 levels in serum(P<0.05 or P<0.01), decreased IL-1β and IL-18 levels in the lungs(P<0.01) and alleviated pathological injury to the lungs.Conclusion: PPM could attenuate LPS-induced inflammation by inhibiting the NF-κB-ROS/NLRP3 pathway, and may be a novel potential candidate drug for treating inflammation and inflammation-related diseases.