Hydrogen-rich water regulates effects of ROS balance on morphology, growth and secondary metabolism via glutathione peroxidase in Ganoderma lucidum.

Ganoderma lucidum is one of the most important medicinal fungi, but the lack of basic study on the fungus has hindered the further development of its value. To investigate the roles of the redox system in G. lucidum, acetic acid (HAc) was applied as a reactive oxygen species (ROS) stress inducer, and hydrogen-rich water (HRW) was used to relieve the ROS stress in this study. Our results demonstrate that the treatment of 5% HRW significantly decreased the ROS content, maintained biomass and polar growth morphology of mycelium, and decreased secondary metabolism under HAc-induced oxidative stress. Furthermore, the roles of HRW were largely dependent on restoring the glutathione system under HAc stress in G. lucidum. To provide further evidence, we used two glutathione peroxidase (GPX)-defective strains, the gpxi strain, the mercaptosuccinic acid (MS, a GPX inhibitor)-treated wide-type (WT) strain, and gpx overexpression strains for further research. The results show that HRW was unable to relieve the HAc-induced ROS overproduction, decreased biomass, mycelium morphology change and increased secondary metabolism biosynthesis in the absence of GPX function. The gpx overexpression strains exhibited resistance to HAc-induced oxidative stress. Thus, we propose that HRW regulates morphology, growth and secondary metabolism via glutathione peroxidase under HAc stress in the fungus G. lucidum. Furthermore, our research also provides a method to study the ROS system in other fungi.

Transcript and metabolite alterations increase ganoderic acid content in Ganoderma lucidum using acetic acid as an inducer.

Acetic acid at 5-8 mM increased ganoderic acid (GA) accumulation in Ganoderma lucidum. After optimization by the response surface methodology, the GA content reached 5.5/100 mg dry weight, an increase of 105% compared with the control. The intermediate metabolites of GA biosynthesis, lanosterol and squalene also increased to 47 and 15.8 µg/g dry weight, respectively, in response to acetic acid. Acetic acid significantly induced transcription levels of sqs, lano, hmgs and cyp51 in the GA biosynthesis pathway. An acetic acid-unregulated acetyl coenzyme A synthase (acs) gene was selected from ten candidate homologous acs genes. The results indicate that acetic acid alters the expression of genes related to acetic acid assimilation and increases GA biosynthesis and the metabolic levels of lanosterol, squalene and GA-a, thereby resulting in GA accumulation.

PI3K/Akt signaling is involved in the pathogenesis of bleomycin­induced pulmonary fibrosis via regulation of epithelial­mesenchymal transition.

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease characterized by chronic inflammation, fibroblast proliferation and extracellular matrix deposition. However, the molecular and cellular mechanisms underlying the pathogenesis of pulmonary fibrosis remain to be fully elucidated. The contribution of the phosphoinositide 3­kinase (PI3K)/protein kinase B (Akt) pathway in fibrotic processes remains to be investigated. The aim of the present study was to investigate the role of the PI3K/Akt pathway in pulmonary fibrosis. A rat model of pulmonary fibrosis was induced by intratracheal administration of bleomycin (BLM), and a specific PI3K/Akt inhibitor, LY294002, was used to assess the role of the PI3K/Akt pathway in fibrogenesis. The inflammatory and fibrotic alterations in the lung tissues were evaluated using histological staining and the hydroxyproline assay. In addition, the concentration of cytokines in bronchoalveolar lavage fluid and the expression of Akt, phosphorylated (p­)Akt, epithelial cadherin, α smooth muscle actin and vimentin in lung tissues. The data demonstrated that an increase in the expression levels of p­Akt was involved in the progression of pulmonary fibrosis and contributed to fibrogenesis. Administration of the Akt inhibitor significantly attenuated inflammation and fibrosis, which was accompanied by a reversal of lung fibrosis­associated epithelial­mesenchymal transition. Taken together, these observations suggest that the PI3K/Akt pathway serves a central role in the pathophysiology of lung fibrosis, and is a promising therapeutic target.

Up-regulation of microRNA-302a inhibited the proliferation and invasion of colorectal cancer cells by regulation of the MAPK and PI3K/Akt signaling pathways.

Aberrant expression of microRNA-302a (miR-302a) has been frequently reported in some cancers excluding colorectal cancer (CRC). However, the role of miR-302a in CRC has not been reported. In this paper, we examined the effect of miR-302a overexpression on proliferation and invasion in CRC cells. The mRNA level of miR-302a in CRC cell lines was determined by real-time PCR. The miR-302a mimic was transiently transfected into CRC cells using Lipofectamine™ 2000 reagent. Subsequently, cell proliferation and invasion were assessed by MTT and Transwell assays. Western blot and ELISA assay were used to detect the expressions and secretions of matrix metalloproteinases (MMPs). Moreover, the expressions of epithelial marker, mesenchymal markers and transcription factors were also determined by Western blot. In addition, the effects of miR-302a overexpression on the MAPK and PI3K/Akt signaling pathways were investigated by Western blot. Our results showed that the mRNA level of miR-302a was remarkably decreased in CRC cell lines compared with normal colon epithelium cells. Up-regulation of miR-302a inhibited the proliferation and invasion of CRC cells. The expressions and secretions of MMP-9 and -2 were evidently reduced by increasing miR-302a. Besides, we found a decrease of ß-catenin, fibronection, vimentin, Snail, Slug, ZEB1 and ZEB2 expressions and an increase of E-cadherin expression. We also found that miR-302a overexpression might decrease the phosphorylation of Erk1/2 and Akt. Altogether, our results indicated that miR-302a overexpression was shown to inhibit proliferation and invasion of CRC cells by reducing the expressions of related proteins through suppressing the MAPK and PI3K/Akt signaling pathways.