Novel anti-inflammatory target of geniposide: Inhibiting Itgß1/Ras-Erk1/2 signal pathway via the miRNA-124a in rheumatoid arthritis synovial fibroblasts.

Geniposide (GE) is an active component isolated from the fruit of Gardenia jasminoides Ellis that has anti-inflammatory and other pharmacological effects; however, the underlying mechanism of GE action has not been elucidated in rheumatoid arthritis (RA). Previous studies have shown that GE plays a therapeutic role in RA via regulation of the integrin beta 1 (Itgß1)-mediated Ras-Erk1/2 signalling pathway. However, the specific mechanism of GE action on Itgß1 has not been clarified. Recent evidence indicates that microRNAs (miRNAs) are involved in the development of RA. In this study, we developed a miRNA-124a-based synoviocyte repair strategy. We demonstrated that miRNA-124a can directly inhibit the expression of the Itgß1 gene and decrease TNF-α-stimulated cell proliferation in vitro. MH7A cells were obtained from the patient with RA and treated with GE in the presence of TNF-α (10 ng/mL). Additionally, we demonstrated that the expression of miRNA-124a can be regulated by GE. GE upregulated the expression of miRNA-124a and decreased the expression of Itgß1 at the mRNA and protein levels. The results of the present study are the first to suggest that GE inhibits TNF-α-stimulated cell proliferation and blocks the activation of the Ras-Erk1/2 pathway via the upregulation of miRNA-124a expression. Our study elucidates the role of miRNA-124a as a protected miRNA in RA and may provide a novel strategy for the diagnosis and treatment of RA in the future.

Genipin inhibits allergic responses in ovalbumin-induced asthmatic mice.

Genipin is a natural compound isolated from the fruit of Gardenia jasminoides with various pharmacological effects. In this study, we investigated whether genipin effectively alleviates allergic responses in a murine model of ovalbumin (OVA)-induced asthma. The mice were administered an intraperitoneal injection of OVA on day 0 and 14 to boost the immune response; genipin was then administered from day 18 to 23 by oral gavage. On days 21 to 23, mice were OVA-challenged using am ultrasonic nebulizer, and airway hyperresponsiveness (AHR) was determined on day 24 by plethysmography. Genipin significantly reduced the inflammatory cell count in bronchoalveolar lavage fluids (BALF) and AHR, which were accompanied by lower interleukin-5 (IL-5), IL-13 and OVA-specific immunoglobulin (Ig) E levels in the BALF or serum from OVA-induced asthmatic mice. In histology, genipin significantly decreased airway inflammation and mucus hypersecretion in OVA-induced asthmatic mice. Additionally, genipin inhibited OVA-induced increases in the expression of inducible nitric oxide synthase and cyclooxygenase-2 proteins. Further, genipin reduced the activity and protein levels of matrix metalloproteinase-9 in lung tissue from OVA induced asthmatic mice. Overall, genipin effectively alleviated the asthmatic inflammatory response in an OVA-induced asthmatic model. Therefore, our results suggest that genipin has therapeutic potential for treating asthma.

Genipin attenuates sepsis-induced immunosuppression through inhibition of T lymphocyte apoptosis.

Sepsis, a systemic inflammatory response to infection, initiates a complex immune response consisting of an early hyperinflammatory response and a subsequent hypoinflammatory response that impairs the removal of infectious organisms. The importance of sepsis-induced immunosuppression and its contribution to mortality has recently emerged. Apoptotic depletion of T lymphocytes is a critical cause of immunosuppression in the late phase of sepsis. Genipin is a major active compound of gardenia fruit that has anti-apoptotic and anti-microbial properties. This study investigated the mechanisms of action of genipin on immunosuppression in the late phase of sepsis. Mice received genipin (1, 2.5 and 5mg/kg, i.v.) at 0 (immediately) and 24h after cecal ligation and puncture (CLP). Twenty-six hours after CLP, the spleen and blood were collected. Genipin improved the survival rate compared to controls. CLP increased the levels of FADD, caspase-8 and caspase-3 protein expression, which were attenuated by genipin. Genipin increased the level of anti-apoptotic B-cell lymphoma-2 protein expression, while it decreased the level of pro-apoptotic phosphorylated-Bim protein expression in CLP. CLP decreased the CD4(+) and CD8(+) T cell population, while it increased the regulatory T cell (Treg) population and the level of cytotoxic T lymphocyte-associated antigen 4 protein expression on Treg. These changes were attenuated by genipin. The splenic levels of interferon-γ and interleukin (IL)-2 were reduced, while the levels of IL-4 and IL-10 increased after CLP. Genipin attenuated these alterations. These findings suggest that genipin reduces immunosuppression by inhibiting T lymphocyte apoptosis in the late phase of sepsis.

Anti-inflammatory effects and pharmacokinetics study of geniposide on rats with adjuvant arthritis.

The aim of this study was to explore the anti-inflammatory effects of Geniposide (GE), an iridoid glycoside compound extracted from Gardenia jasminoides Ellis (GJ) fruit in adjuvant-induced arthritis (AA) rats and its pharmacokinetic (PK) basis. AA was induced by injecting with Freund's complete adjuvant (FCA). Male SD rats were subjected to treatment with GE (30, 60 and 120mg/kg) from day 17 to 24 after immunization. Fibroblast-like synoviocyte (FLS) proliferation was assessed by MTT. Interleukin (IL)-1, IL-6, TNF-α and IL-10 were determined using double-sandwich enzyme-linked immunosorbent assay (ELISA). Expression of p38 mitogen-activated protein kinases (p38MAPKs) related proteins in FLS was detected by Western blotting. PK profiles were simultaneously detected by ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS) in AA rat plasma after oral administration of GE on day 17 after immunization. As a result, GE promoted the recovery of arthritis and inhibited the colonic inflammation damage in AA rats by decreasing the expression level of TNF-α, IL-1 and IL-6, increasing the production of IL-10 and inhibiting the expression of phospho-p38 (p-p38) related proteins in FLS. PK parameters (AUC, Cmax and t1/2) tended to be associated with dosage-related decreasing of efficacy index.