Study on effect of anemoside B4 in improving COPD rats by regulating IL-12/STAT4 and IL-4/STAT6 signaling pathways / 中国中药杂志

To study the effect of anemoside B4 on rats with chronic obstructive pulmonary disease (COPD).Seventy-two SD male rats were randomly divided into blank group and model group.The method of exposure to cigarette smoke and combined with lipopolysaccharide (LPS) was used to replicate the rat model of COPD.After the model was maintained for 5 weeks,the rats were randomly divided into model group,dexamethasone group (0.81 mg·kg~(-1)) and anemoside B4 low,medium and high (2,4,8 mg·kg~(-1)) dose groups,a group of 12 animals were administered,and then the administration was started.The administration was maintained until the28th day,and the pulmonary function parameters of rats were measured by an animal pulmonary function instrument.After testing the rat lung function parameters,immediately draw rat alveolar lavage fluid (BALF),and use high-throughput protein chip technology to determined the expression levels of inflammatory cytokines in rat BALF.HE staining was used to observe the general pathological changes of rat lung and tracheal tissue.Masson staining was used to observe the collagen deposition in rat lung tissue.Real-time q PCR method was used to determine the mRNA expression level of related genes in rat lung tissue.Western blot method was used to determine the expression levels of related proteins in rat lung tissues.According to the findings,compared with the model group,the dexamethasone group and the anemoside B4 drug groups had different degrees of increase in the lung function parameters of rats (P<0.01,P<0.05),improved the expression level of inflammatory cytokines in the BALF of rats to varying degrees (P<0.01,P<0.05),and improved the pathological structure of rat lung tissue to varying degrees.Relative mRNA expressions of matrix metalloproteinase 2 (MMP-2),matrix metalloproteinase 12 (MMP-12),matrix metalloproteinase inhibitor 1 (TIMP-1),interleukin-6 (IL-6),and transforming growth factor-β1 (TGF-β1) were significantly reduced (P<0.01);whereas relative mRNA expressions of matrix metalloproteinase 9(MMP-9) and matrix metalloproteinase inhibitor 2 (TIMP-2) were increased significantly (P<0.01).The mRNA and protein expression levels of T-box transcription factor (T-bet),interleukin-12 (IL-12) and signal transducer and activator of transcription 4(STAT4) reduced to varying degrees (P<0.01,P<0.05).The mRNA of transcription factor GATA3 (binding protein-3),interleukin-4 (IL-4) and signal transducer and activator of transcription 6 (STAT6) in rat lung tissues and the protein expression levels of IL-4 and STAT6 were increased to varying degrees (P<0.01,P<0.05).In conclusion,anemoside B4 has a certain protective effect on COPD rats caused by cigarette smoke exposure and combined with LPS.The mechanism of action may be related to the regulation of IL-12/STAT4 and IL-4/STAT6 signaling pathways.

Afatinib Reduces STAT6 Signaling of Host ARPE-19 Cells Infected with Toxoplasma gondii

Specific gene expressions of host cells by spontaneous STAT6 phosphorylation are major strategy for the survival of intracellular Toxoplasma gondii against parasiticidal events through STAT1 phosphorylation by infection provoked IFN-γ. We determined the effects of small molecules of tyrosine kinase inhibitors (TKIs) on the growth of T. gondii and on the relationship with STAT1 and STAT6 phosphorylation in ARPE-19 cells. We counted the number of T. gondii RH tachyzoites per parasitophorous vacuolar membrane (PVM) after treatment with TKIs at 12-hr intervals for 72 hr. The change of STAT6 phosphorylation was assessed via western blot and immunofluorescence assay. Among the tested TKIs, Afatinib (pan ErbB/EGFR inhibitor, 5 µM) inhibited 98.0% of the growth of T. gondii, which was comparable to pyrimethamine (5 µM) at 96.9% and followed by Erlotinib (ErbB1/EGFR inhibitor, 20 µM) at 33.8% and Sunitinib (PDGFR or c-Kit inhibitor, 10 µM) at 21.3%. In the early stage of the infection (2, 4, and 8 hr after T. gondii challenge), Afatinib inhibited the phosphorylation of STAT6 in western blot and immunofluorescence assay. Both JAK1 and JAK3, the upper hierarchical kinases of cytokine signaling, were strongly phosphorylated at 2 hr and then disappeared entirely after 4 hr. Some TKIs, especially the EGFR inhibitors, might play an important role in the inhibition of intracellular replication of T. gondii through the inhibition of the direct phosphorylation of STAT6 by T. gondii.

STAT6 Expression and IL-13 Production in Association with Goblet Cell Hyperplasia and Worm Expulsion of Gymnophalloides seoi from C57BL/6 Mice

In intestinal helminth infections, Th2 immune respones are generally associated with mucin secretion for worm expulsion from the host intestine. In particular, IL-4 and IL-13 are the important cytokines related with intestinal mucus production via STAT6 signalling in nematode infections. However, this perspective has never been studied in Gymnophalloides seoi infection. The present study aimed to observe the STAT6 signalling and cytokine responses in C57BL/6 mice, a mouse strain resistant to infection with this trematode. The results showed that worm expulsion occurred actively during days 1-2 post-infection (PI), when goblet cells began to proliferate in the small intestine. The STAT6 gene expression in the mouse spleen became remarkable from day 2 PI. Moreover, G. seoi infection induced a significant increase of IL-13 from day 4 PI in the spleen of infected mice. Our results suggested that goblet cell hyperplasia and worm expulsion in G. seoi-infected mice should be induced by STAT6 signalling, in which IL-13 may be involved as a dominant triggering cytokine.

Effects of Scutellarin on MUC5AC Mucin Production Induced by Human Neutrophil Elastase or Interleukin 13 on Airway Epithelial Cells

Scutellarin is a flavonoid extracted from a traditional Chinese herb, Erigeron breviscapus. The present study investigated the effect of scutellarin on MUC5AC mucin production and the possible mechanism. Human bronchial epithelial 16 (HBE16) cells were pretreated with scutellarin for 60 min, and then exposed to human neutrophil elastase (HNE) or interleukin (IL)-13 for 12 hr. RT-PCR and ELISA were performed to measure the amount of MUC5AC mucin production. The results showed that scutellarin inhibited MUC5AC expression both in mRNA and protein level induced by HNE in a concentration-dependent manner. However, scutellarin failed to inhibit MUC5AC mucin production induced by IL-13. To investigate the intracellular mechanisms associated with the effect of scutellarin on MUC5AC mucin production, western blotting was carried out to examine the phosphorylation of protein kinase C (PKC), signal transducer and activator of transcription 6 (STAT6) and extracellular signal-regulated kinase 1/2 (ERK1/2). The phosphorylation of PKC and ERK1/2 was attenuated after treatment with scutellarin, whereas STAT6 was not significantly affected. Therefore, it is suggested that scutellarin down-regulates MUC5AC mucin production on HBE16 cells via ERK-dependent and PKC-dependent pathways.