Isoforskolin and Cucurbitacin IIa promote the expression of anti-inflammatory regulatory factor SIGIRR in human macrophages stimulated with Borrelia burgdorferi basic membrane protein A

Cucurbitacins mitigate vascular neointimal hyperplasia by suppressing cyclin A2 expression and inhibiting VSMC proliferation

BACKGROUND

Restenosis frequently occurs after percutaneous angioplasty in patients with vascular occlusion and seriously threatens their health. Substantial evidence has revealed that preventing vascular smooth muscle cell proliferation using a drug-eluting stent is an effective approach to improve restenosis. Cucurbitacins have been demonstrated to exert an anti-proliferation effect in various tumors and a hypotensive effect. This study aims to investigate the role of cucurbitacins extracted from Cucumis melo L. (CuECs) and cucurbitacin B (CuB) on restenosis.

METHODS

C57BL/6 mice were subjected to left carotid artery ligation and subcutaneously injected with CuECs or CuB for 4 weeks. Hematoxylin-Eosin, immunofluorescence and immunohistochemistry staining were used to evaluate the effect of CuECs and CuB on neointimal hyperplasia. Western blot, real-time PCR, flow cytometry analysis, EdU staining and cellular immunofluorescence assay were employed to measure the effects of CuECs and CuB on cell proliferation and the cell cycle in vitro. The potential interactions of CuECs with cyclin A2 were performed by molecular docking.

RESULTS

The results demonstrated that both CuECs and CuB exhibited significant inhibitory effects on neointimal hyperplasia and proliferation of vascular smooth muscle cells. Furthermore, CuECs and CuB mediated cell cycle arrest at the S phase. Autodocking analysis demonstrated that CuB, CuD, CuE and CuI had high binding energy for cyclin A2. Our study also showed that CuECs and CuB dramatically inhibited FBS-induced cyclin A2 expression. Moreover, the expression of cyclin A2 in CuEC- and CuB-treated neointima was downregulated.

CONCLUSIONS

CuECs, especially CuB, exert an anti-proliferation effect in VSMCs and may be potential drugs to prevent restenosis.

A key protein from Borrelia burgdorferi could stimulate cytokines in human microglial cells and inhibitory effects of Cucurbitacin IIa

Lyme neuroborreliosis (LNB) is an infectious disease of the nervous system caused by Borrelia burgdorferi (Bb) infection. However, its pathogenesis is not fully understood. We used recombinant BmpA (rBmpA) to stimulate human microglia cell HMC3, then collected the culture supernatant and extracted total RNA from cells, and used the supernatant for cytokine chip, then ELISA and qPCR technology were used to validate the results from cytokine chip. After rBmpA stimulation of microglia, 24 inflammation-related cytokines showed elevated expression. Among them, six cytokines (IL-6, IL-8, CCL2, CCL5, CXCL1, and CXCL10) increased significantly in mRNA transcription, three cytokines (IL-6, IL-8, and CXCL10) concentrations in the cell supernatant increased significantly after the rBmpA stimulation, and CuIIa could inhibit expression of these cytokines. The BmpA can stimulate human microglia to produce large amounts of cytokines, leading to the occurrence of inflammation, which may be closely related to the development of LNB. CuIIa can inhibit BmpA-induced cytokine production in microglia, which may have potential therapeutic effects on LNB.

Pharmacokinetics and Biological Activity of Cucurbitacins

Cucurbitacins are a class of secondary metabolites initially isolated from the Cucurbitaceae family. They are important for their analgesic, anti-inflammatory, antimicrobial, antiviral, and anticancer biological actions. This review addresses pharmacokinetic parameters recently reported, including absorption, metabolism, distribution, and elimination phases of cucurbitacins. It includes recent studies of the molecular mechanisms of the biological activity of the most studied cucurbitacins and some derivatives, especially their anticancer capacity, to propose the integration of the pharmacokinetic profiles of cucurbitacins and the possibilities of their use. The main botanical genera and species of American origin that have been studied, and others whose chemo taxonomy makes them essential sources for the extraction of these metabolites, are summarized.

Comparative transcriptome analysis and identification of candidate genes involved in cucurbitacin IIa biosynthesis in Hemsleya macrosperma

Hemsleya macrosperma (H. macrosperma) is widely used in southwestern China as folk medicine with various bioactivities. Cucurbitacin IIa is the main active component in H. macrosperma and draws increased attention for its potential pharmacological activities. In order to reveal the mechanism of cucurbitacin IIa biosynthesis and regulation in H. macrosperma, transcriptome analysis was performed to compare differentially expressed genes in three tissues (root tuber, stem and leaf). A total of 47 946 unigenes were generated from these tissues and 55 unigenes were identified as candidate genes involved in triterpenoid backbone biosynthesis. Three homologous genes encoding squalene epoxidase (HmSE) were discovered and successfully expressed in a prokaryotic system. HmSE1 was found to be responsible for oxidization of squalene. In addition, several cytochrome P450s and transcription factors were predicted as candidates associated to cucurbitacin IIa biosynthesis. Notably, the expression profiles of those putative genes showed a positive correlation with elevated curcurbitacin IIa production in methyl jasmonate-elicited suspension cells of H. macrosperma., suggesting probable functions of the candidates on curcurbitacin IIa biosynthesis. These findings provide insights on cucurbitacin IIa biosynthesis and regulation in H. macrosperma.

Cucurbitacin I exhibits anticancer efficacy through induction of apoptosis and modulation of JAK/STAT3, MAPK/ERK, and AKT/mTOR signaling pathways in HepG2 cell line

Hepatocellular carcinoma is a common cancer type, especially among men. Although cucurbitacin I (CuI), widely found in plants belonging to the Ecballium elaterium (E. L) plant family, has been shown to have antitumorigenic properties in many cancer types, its anticancer effect, molecular mechanism, and apoptotic effect mediated by signal pathways on hepatocellular carcinoma have not been fully clarified. In the present study, we investigated the anticancer effect of CuI treated at different doses on the HepG2 cell line and the underlying mechanism in vitro. High-purity CuI was obtained from the E. elaterium plant with the aid of HPLC. The effects of this substance on the viability of cells were studied by the MTT assay. The effects of CuI on cell cycle progression and apoptosis were studied with flow cytometry. DNA breaks were analyzed by the Comet assay method. The proteins and genes involved in the JAK/STAT3, MAPK/ERK, and AKT/mTOR signaling pathways were investigated using Western blot and qRT-PCR, respectively. The results of this study demonstrated that CuI significantly reduced HepG2 cell growth in vitro, induced antiproliferation, and G2/M phase of the cell cycle was interrupted. PRACTICAL APPLICATIONS: CuI administration was shown to downregulate the levels of proteins in the PI3K/AKT/mTOR, MAPK, and JAK2/STAT3 cascades in HepG2 cells. CuI also reduced the expression of MAPK, STAT3, mTOR, JAK2, and Akt genes in different concentrations. DNA breaks are formed as a result of this effect. CuI, by reducing cell proliferation and promoting apoptosis, was found to have potential as a chemotherapeutic agent of hepatocellular carcinoma.

Xuedan Sustained Release Pellets Ameliorate Dextran Sulfate Sodium-Induced Ulcerative Colitis in Rats by Targeting Gut Microbiota and MAPK Signaling Pathways

Cucurbitacins have a variety of bioactivities, such as anticancer, anti-inflammatory, antidepressant-like, and antiviral effects, but their pharmacological effect in ulcerative colitis (UC) has not been reported until now. Thus, this study aims to investigate the preventive effects of Xuedan sustained release pellets (XSPs) on UC rats and the underlying mechanisms. XSPs were prepared by extracting cucurbitacins from Hemsleya. Experimental UC rats were induced by the intake of 4% dextran sulfate sodium (DSS) for a week and treated with different doses of XSP (0.95, 1.90, and 3.8 mg/kg). The body weight, colon length, disease activity index (DAI), and histological changes of colonic tissue were measured. In addition, the expressions of pro-inflammatory cytokines were detected by using the enzyme-linked immunosorbent assay. Pathways involved in the intestinal inflammation were targeted by RNA-sequencing. Moreover, the changes of gut microbial diversity and composition were analyzed by the 16SrNA analysis and the contents of short-chain fatty acids (SCFAs) were detected by GC-MS. The results revealed that XSP intervention greatly restored the weight loss and colonic shortening (p < 0.05) and reduced the raised DAI scores, myeloperoxidase, and nitric oxide activities in UC in rats (p < 0.05). XSP administration also downregulated the protein levels of pro-inflammatory factors IL-1β, IL-6, and TNF-α. Notably, it was found that XSP considerably suppressed the activation of the MAPK signaling pathway. In addition, XSP treatment improved the balance of gut microbiota that was disturbed by DSS. The beneficial bacteria Lachnospiraceae_NK4A136 group and Lactobacillus at the genus level significantly increased in the XSP group, which had decreased with the use of DSS (p < 0.05). Pathogenic bacteria including Escherichia-Shigella and Bacteroides in UC in rats were reduced by XSP intervention. Furthermore, XSP significantly elevated the production of SCFAs in UC in rats (p < 0.05). These alterations in inflammatory status were accompanied with changes in gut microbiota diversity and SCFA production. In conclusion, XSP exhibited protective effects against DSS-induced UC in rats. XSP treatment decreased inflammation via modulation of gut microbiota composition and SCFA production.