Interaction between piperine and genes associated with sciatica and its mechanism based on molecular docking technology and network pharmacology

Abstract

Piperine is the main active component of Piper longum L., which is also the main component of anti-sciatica Mongolian medicine Naru Sanwei pill. It has many pharmacological activities such as anti-inflammatory and immune regulation. This paper aims to preliminarily explore the potential mechanism of piperine in the treatment of sciatica through network pharmacology and molecular docking. TCMSP, ETCM database and literature mining were used to collect the active compounds of Piper longum L. Swiss TargetPrediction and SuperPred server were used to find the targets of compounds. At the same time, CTD database was used to collect the targets of sciatica. Then the above targets were compared and analyzed to select the targets of anti-sciatica in Piper longum L. The Go (gene ontology) annotation and KEGG pathway of the targets were enriched and analyzed by Metascape database platform. The molecular docking between the effective components and the targets was verified by Autodock. After that, the sciatica model of rats was established and treated with piperine. The expression level of inflammatory factors and proteins in the serum and tissues of rat sciatic nerve were detected by ELISA and Western blot. HE staining and immunohistochemistry were carried out on the sciatica tissues of rats. The results showed that Piper longum L. can regulate the development of sciatica and affect the expressions of PPARG and NF-kB1 through its active ingredient piperine, and there is endogenous interaction between PPARG and NF-kB1.

Keywords: Molecular docking; NF-kB1; Network pharmacology; PPARG; Piperine; Sciatica.

Fig. 1

a The 3D structure of piperine; b the Metascape platform to select the top GO annotation results and KEGG pathway; c the map of differential gene enrichment interaction, including 20 groups of enrichment results; d the network map constructed according to the enrichment degree, the darker the color is, the more genes are enriched into the pathway

Fig. 2

a The fully connected interaction network of all gene-related proteins; b the module substructure recognized in the interaction network; c the modules are abstracted from the fully connected interactive network. d The key gene corresponding to the target protein on the pathway

Fig. 3

a The site binding of celecoxib and PPARG. The blue is the 3D structure of celecoxib, and the yellow is LYS-358, the amino acid residue of PPARG; b the site binding of celecoxib and NF-kB1. The blue is the celecoxib, and the yellow is LYS-275, the amino acid residue of NF-kB1; c the site binding of piperine and PPARG. The blue is the 3D structure of piperine, and the yellow is LYS-367, the amino acid residue of PPARG; d the site binding of piperine and NF-kB1. The blue is the piperine, and the yellow is PHE-298, the amino acid residue of NF-kB1

Fig. 4

a The expressions of IL-1β, TNF-α, IL-10 and TGF-β1 at protein levels of rat sciatic nerve in four groups. b–e The contents of IL-1 β, TNF-α, IL-10 and TGF-β1 in serum of four groups. ##P < 0.01 compared with sham rats. **P < 0.01 compared with model rats

Fig. 5

Pathological effects of piperine on sciatica model rats. a The HE staining results of the model group and piperine group, respectively. b The results of PPARG and NF-kB1 immunohistochemistry in the model group and piperine group, respectively, and the positive expression appeared in the cytoplasm

Fig. 6

Western blot and immunocoprecipitation. a Western blot showed that NF-kB1 expression in piperine group was significantly lower at 15 days than that at 7 days (P < 0.01), and PPARG expression increased with piperine administration (P < 0.01). b Immunocoprecipitation showed that PPARG was detected in the experimental group, but not in the negative control group, indicating that NF-kB1 protein and PPARG protein can specifically bind