Dendrobium mixture ameliorates hepatic injury induced by insulin resistance in vitro and in vivo through the downregulation of AGE/RAGE/Akt signaling pathway.

Dendrobium mixture (DM) is a patented Chinese herbal medicine which has been shown to ameliorate type 2 diabetes mellitus (T2DM) with non-alcoholic fatty liver disease (NAFLD) in vivo and in vitro. We aimed to investigate the underlying mechanism of DM as a therapeutic agent in attenuating liver steatosis in relation to type 2 diabetes mellitus (T2DM). DM (16.2 g/kg/d) was administered to db/db mice for 4 weeks. The db/m mice and db/db mice in the control and model groups were given normal saline. Additionally, DM (11.25 g/kg/d) was administered to Sprague-Dawley (SD) rats, and the serum was collected and used in an experiment involving palmitic acid (PA)-induced human liver HepG2 cells with abnormal lipid and glucose metabolism. In db/db mice, the administration of DM significantly alleviated liver steatosis, including histological damage and cell apoptosis. DM was found to prevent the upregulation of the RAGE and AKT1 proteins in liver tissues. The underlying mechanism of DM was further studied in PA-induced HepG2 cells. Post-DM administration serum from SD rats reduced lipid accumulation and regulated glucose metabolism in HepG2 cells. Consequently, it inhibited RAGE/AKT signaling and restored autophagy activity. The upregulated autophagy was associated with the mTOR-AMPK signaling pathway. Furthermore, post-DM administration serum reduced apoptosis of hepatocytes in PA-induced HepG2 cells. Our study supports the potential use of DM as a therapeutic agent for the treatment of NAFLD in T2DM. The mechanism underlying this therapeutic potential is associated with the downregulation of the AGE/RAGE/Akt signaling pathway.

Inhibitory Effect of Gualou Guizhi Decoction on Microglial Inflammation and Neuron Injury by Promoting Anti-Inflammation via Targeting mmu-miR-155.

Gualou Guizhi decoction (GLGZD) treatment exerts neuroprotective effects and promotes spasticity following ischemic stroke. However, the molecular mechanism of GLGZD treatment on ischemic stroke remains unclear. Our previous study indicated that GLGZD ameliorates neuronal damage caused by secondary inflammatory injury induced by microglia. In the present study, we investigate the potential mechanism of GLGZD treatment on neuron damage induced by neuroinflammation via mmu-miR-155 in vitro. The HT22 cell line and the BV2 cell line were exposed to oxygen/glucose-deprive (OGD) conditions; the conditioned medium was prepared using the supernatants from OGD-stimulated BV2 cells after pretreating with GLGZD. Cell viability was determined by MTT assays; levels of released inflammatory cytokines were assessed using the BioPlex system. mmu-miR-155 and its targeting genes were detected using real-time reverse transcription polymerase chain reaction (RT-PCR). The expression of anti-inflammatory proteins was evaluated by Western blotting. DAPI staining was used to test the apoptotic cells. Our results showed that GLGZD pretreatment significantly induced IL10 release and decreased the production of TNF-α, IL6, and IFN-γ. In addition, GLGZD markedly attenuated mmu-miR-155 expression and its downstream SOCS1, SMAD2, SHIP1, and TAB2 expression levels. The DAPI-stained apoptotic cell death and caspase-3 activation in HT22 cells exposed to the conditioned medium were reversed by GLGZD treatment. Our findings suggested that GLGZD pretreatment downregulates the mmu-miR-155 signaling, which inhibits microglial inflammation, thereby resulting in the suppression of neuron apoptosis after OGD stress. The underlying mechanisms may provide the support for GLGZD treatment of cerebral ischemic injury.

The inhibitory effect of Gualou Guizhi Decoction on post-ischemic neuroinflammation via miR-155 in MCAO rats.

BACKGROUND: Gualou Guizhi Decoction (GLGZD) is commonly used to treat stroke. The present study investigated the potential roles of GLGZD on inflammation involving microRNA-155 (miR-155) in a model of ischemic stroke using middle cerebral artery occlusion (MCAO) rats. METHODS: Sprague-Dawley rats were randomly divided into three groups: Sham operated group, MCAO model group, and GLGZD treatment group. The ischemic model was established by 2 h left MCAO followed by reperfusion. Neurological deficits were evaluated with a modified Ashworth scale in each group. The changes in individual paw parameters were assessed by Catwalk gait analysis. Inflammatory cytokines were measured by enzyme linked immunosorbent assay (ELISA) and protein levels and gene expression related to inflammation were detected by Western blot and quantitative reverse transcription-PCR (qRTPCR) assays, respectively. The expression of inflammatory signaling proteins was additionally detected by immunohistochemistry. RESULTS: Treatment of MCAO rats with GLGZD improved neuronal defects and limb motivity. Additionally, GLGZD was able to inhibit miR-155 upregulation, resulting in down-regulation of miR155-targeted molecules in MCAO rats, including suppressor of cytokine signaling 1 (SOCS1), inhibitor of nuclear factor kappa-B kinase (IKK), mothers against decapentaplegic homolog 2 (SMAD2) and CCAAT/ enhancer binding protein beta (CEBPß). Meanwhile, the production of anti-inflammatory cytokines was dramatically enhanced by GLGZD treatment when comparing with the MCAO model group. CONCLUSIONS: In conclusion, GLGZD down-regulates miR-155, mediating subsequent neuroinflammation and resulting in neuroprotection which contributes to reduced spasticity after ischemic stroke.

GuaLou GuiZhi decoction represses LPS-induced BV2 activation via miR-155 induced inflammatory signals.

Inflammatory response that occur post-ischemia is a serious problem in the treatment of ischemic brain disease. MicroRNA-155 is a brain-specific or brain-enriched miRNA, which mediates inflammatory reactions in cerebral ischemic tissue by regulating inflammatory signal and the expression level of SOCS1. The present study was aimed to assess the effect of GuaLou GuiZhi Decoction (GLGZD) on miR-155 expression in activated microglia following inflammation and further explore the role of GLGZD on expression of the inflammation-related gene. BV2 cells were used to simulated by LPS to make the inflammatory model. Expression level of miR-155 was detected by Real-Time PCR. BV2 cells after simulated by LPS were then transfected with miR-155 mimic and its negative controls. Cytokines release were measured by corresponding purchased ELISA kits, respectively. Then target protein expression of miR-155 were detected by western blotting assay. After miRNA over expression transfections, expressions of inflammation-related factors, SOCS-1 and SAMD in BV2 cells after activation were measured by Western blot assay. Results showed that in BV2 cells after simulated by LPS, miR-155 was upregulated. The elevated miR-155 expression enhanced the inflammatory cytokine release. miR-155 directly target and negatively regulated SOCS-1 and SMAD-1 expression. Over expression of SOCS-1 and SMAD reduced inflammatory action that was enhanced by miR-155 mimic transfection. miR-155 was positively related with activation of NF-Ï°B signal pathways via SOCS-1 and SMAD. In conclusion, GuaLou GuiZhi Decoction (GLGZD) might exert its anti-inflammatory action by inhibiting the expression of miR-155, indicating that miR-155 may be used as a treatment target in clinical treatment with GuaLou GuiZhi Decoction (GLGZD) in ischemic brain.