Objective: ´Three formulas and three medicines,’ namely, Jinhua Qinggan Granule, Lianhua Qingwen Capsule, Xuebijing Injection, Qingfei Paidu Decoction, HuaShi BaiDu Formula, and XuanFei BaiDu Granule, were proven to be effective for coronavirus disease 2019 (COVID-19) treatment. The present study aimed to identify the active chemical constituents of this traditional Chinese medicine (TCM) and investigate their mechanisms through interleukin-6 (IL-6) integrating network pharmacological approaches. Methods: We collected the compounds from all herbal ingredients of the previously mentioned TCM, but those that could down-regulate IL-6 were screened through the network pharmacology approach. Then, we modeled molecular docking to evaluate the binding affinity between compounds and IL-6. Furthermore, we analyzed the biological processes and pathways of compounds. Finally, we screened out the core genes of compounds through the construction of the protein–protein interaction network and the excavation of gene clusters of compounds. Results: The network pharmacology research showed that TCM could decrease IL-6 using several compounds, such as quercetin, ursolic acid, luteolin, and rutin. Molecular docking results showed that the molecular binding affinity with IL-6 of all compounds except γ-aminobutyric acid was < −5.0 kJ/mol, indicating the potential of numerous active compounds in TCM to directly interact with IL-6, leading to an anti-inflammation effect. Finally, Cytoscape 3.7.2 was used to topologize the biological processes and pathways of compounds, revealing potential mechanisms for COVID-19 treatment. Conclusion: These results indicated the positive effect of TCM on the prevention and rehabilitation of COVID-19 in at-risk people. Quercetin, ursolic acid, luteolin, and rutin could inhibit COVID-19 by down-regulating IL-6.

Expression of proinflammatory cytokines, such as interleukin (IL)-6 (IL-6) and metalloproteases, are elevated in patients with rotator cuff tear (RCT). In order to investigate the role of IL-6 gene polymorphisms on RCT risk, we genotyped two SNPs on IL-6 gene (rs1800795 and rs1800797) in 138 RCT patients and 137 healthy controls using polymerase chain reaction (PCR) and Sanger sequencing. The IL-6 expression in shoulder joint synovial fluid was determined by using enzyme-linked immunosorbent assay (ELISA) method. The constant score and visual analog scale (VAS) were used to evaluate the clinical outcome of two s (surgicsal vs. conservative) for RCT patients. For rs1800795, individuals with the GG genotype or G allele had significantly higher risk of RCT. Elevated risk of tear size was associated with the GG genotype of the rs1800795 polymorphism. The IL-6 rs1800797 polymorphism was also associated with an increased risk of RCT, especially among female, drinkers, and individuals with B(MI) < 25 kg/m 2 . The elevated levels of IL-6 gene were observed among the mutant genotype of rs1800795/rs1800797 polymorphism. Surgical group is significantly better than conservative treatment from the perspective of constant score and VAS. Furthermore, CG genotype of rs1800795 polymorphism increased the constant score at 6 months in comparison with CC genotype. In conclusion, our study supports a role of IL-6 rs1800795/rs1800797 polymorphisms on increased RCT risk. The RCT patients with CG genotype of rs1800795 polymorphism have more obvious surgical treatment effects by influencing the IL-6 expression.

Objective: To identify the association between the interleukin (IL) 6 ( IL-6 ) rs1800795 (-174 G>C), IL-8 rs4073 (-251T>A), and matrix metalloproteinase-13 ( MMP-13 ) rs2252070 (-77G>A) gene polymorphisms and knee osteoarthritis (KOA) susceptibility in the Chinese Han population. Methods: Genomic DNA was extracted from a total of 400 KOA patients and 400 healthy subjects. Sanger sequencing was performed to determine the genotypes of the IL-6 rs1800795 (-174 G/C), IL-8 rs4073 (-251A/T), and MMP-13 rs2252070 (-77A/G) loci. The mRNA expression levels of IL-6, IL-8 , and MMP-13 in osteoblasts and the protein expression levels of IL-6, IL-8, and MMP-13 in the synovial fluids of KOA patients were analyzed. Results: The recessive model of IL-6 rs1800795 locus was found to be associated with KOA risk (adjusted odds ratio (OR) = 1.657, 95% confidence interval (CI) = 1.396–1.866, P <0.001). The IL-8 rs4073 locus dominant and recessive model showed no significant association with KOA risk ( P >0.05). The dominant and recessive models of the MMP-13 rs2252070 locus showed higher risk for developing KOA (dominant model: adjusted OR = 1.271, 95%CI = 1.095–1.480, P =0.001; recessive model: adjusted OR = 1.361 95%CI = 1.151–1.569, P <0.001). The G>C mutation in IL-6 rs1800795 and the G>A mutation in MMP-13 rs2252070 were associated with significantly higher KOA disease severity. The G>C mutation in the IL-6 rs1800795 locus was associated with up-regulation of IL-6 expression. The G>A mutation in the MMP-13 rs2252070 locus was associated with up-regulation of MMP-13 expression. Conclusion: The IL-8 rs4073 (-251T>A) mutation was not associated with KOA susceptibility. The IL-6 rs1800795 (-174 G>C) and MMP-13 rs2252070 (-77G>A) mutations were associated with KOA susceptibility, increased disease severity, and up-regulation of IL-6 and MMP-13 expression levels.

Large doses of flavonoids could cure many diseases with no serious side effects. However, the role of flavonoids in the treatment of polycystic ovary syndrome (PCOS) has not been reported. Therefore, total flavonoids extracted from Nervilia Fordii were selected to explore its therapeutic efficiency in PCOS. PCOS rat model was constructed to explore the role of total flavonoids in the treatment of PCOS. ELISA was used to assess the changes of ovulation function under the treatment of total flavonoids with or without exogenous interleukin-6 (IL-6). Western blot, real-time PCR and immunohistochemistry were carried out to assess the related molecular mechanisms. We explored that total flavonoids obviously increased the serum levels of follicle-stimulating hormone (FSH), and sharply decreased the serum levels of luteinizing hormone (LH), testosterone (T) and insulin (INS) in the PCOS-IR rats via partly inhibiting the activation of JAK2/STAT3 pathway, partially up-regulating the IL-6 expression and partially down-regulating the suppressor of cytokine signaling 3 (SOCS3) expression in ovaries of PCOS rats. The effect of total flavonoids on estrous cycles, serum levels of FSH, LH, T and INS were partially attenuated by IL-6 in PCOS rat model. Moreover, IL-6 significantly reversed the effect of total flavonoids on the phosphorylation of JAK2/STAT3, the expression of IL-6 and SOCS3 in ovaries of PCOS rats. Total flavonoids extracted from Nervilia Fordii might induce the expression of IL-6 in ovary and act as a potential therapeutic drug for the treatment of PCOS.

Mesenchymal stem cells (MSCs) interact with tumor cells and regulate tumorigenesis and metastasis. As one of the important components of the tumor microenvironment, MSC-secreted cytokines play a critical role in cancer development. However, whether and how bone marrow MSCs (BMSCs) and their secreted cytokines participate in hepatocellular carcinoma (HCC) progression, still remains largely unknown. In the present study, we first measured the concentration of interleukin-6 (IL-6) in BMSC conditioned medium (BMSC-CM). Next, we assessed the changes of invasion ability in response to treatment of BMSC-CM or recombinant IL-6 in two human HCC cell lines Bel-7404 and HepG2. Then we analyzed the level of key components of the IL-6 signal pathway, including IL-6 receptor and signal transducer (i.e. IL-6R and gp130), a transcription factor STAT3 (signal transducer and activator of transcription 3), as well as its target genes BCL2, CCND1, MCL1 and MMP2, in BMSC-CM or recombinant IL-6 treated Bel-7404 and HepG2 cells. Results showed that a considerable amount of IL-6 was secreted by BMSCs, and BMSC-CM markedly elevated Bel-7404 cell invasion rate and stimulated the signal transduction of IL-6/STAT3 pathway. Neutralizing the secreted IL-6 bioactivity by the anti-IL-6 antibody diminished the invasion-promoting effect and down-regulated IL-6/STAT3 pathway of BMSC-CM treated Bel-7404 cells. In conclusion, we found that BMSCs may activate the IL-6/STAT3 signaling pathway and promote cell invasion in Bel-7404 cells, suggesting that this protumor effect should be seriously considered before clinical application of MSC-mediated cancer therapy.

We have previously reported that the human monocytoid cell line U-937-1 constitutively expresses transforming growth factor-alpha (TGF-α) and that the steady-state levels of TGF-α mRNA as well as TGF-α protein release increase when U-937-1 cells are differentiated towards monocytes/macrophages. Interleukin-6 (IL-6), which has been shown to have growth-stimulatory effects on a number of cell types, has recently been shown to enhance TGF-α expression in keratinocytes. In the present study we investigated whether TGF-α expression in macrophage-like cells could be regulated by IL-6 using U-937-1 cells as a model system of monocyte/macrophage differentiation. U-937-1 cells were differentiated with retinoic acid (RA), vitamin D3 (Vit-D3) or phorbol-12-myristate-13-acetate (PMA) for 4 days and were then treated with human recombinant IL-6 (1000 IU/ml) for up to 24 hr. Northern blot analysis revealed that cells differentiated with PMA, inducing the phenotype of a secretory macrophage, markedly increased their TGF-α mRNA levels (2.7-fold) when treated with IL-6; the response was maximal at 6 hr and remained high at 12 hr. The expression of the TGF-α gene was accompanied by release of TGF-α protein into the cell culture medium, irrespective of differentiating agent, as demonstrated by enzyme-linked immunosorbent assay (ELISA), as well as by surface expression of pro-TGF-α as determined by indirect immunofluorescent cytometry. However, the superinduction of the TGF-α gene by IL-6 in cells differentiated with PMA was not accompanied by any increase in TGF-α protein release or pro-TGF-α surface expression. We conclude that since IL-6 causes increased steady-state levels of TGF-α mRNA in macrophage-like cells, it may prime these cells for production of this growth factor. Furthermore, we have shown that the IL-6 receptor complex is functional in U-937-1 cells induced to differentiate towards a secretory macrophage by treatment with PMA.