Involvement of GDH3-encoded NADP+-dependent glutamate dehydrogenase in yeast cell resistance to stress-induced apoptosis in stationary phase cells.

Glutamate metabolism is linked to a number of fundamental metabolic pathways such as amino acid metabolism, the TCA cycle, and glutathione (GSH) synthesis. In the yeast Saccharomyces cerevisiae, glutamate is synthesized from α-ketoglutarate by two NADP(+)-dependent glutamate dehydrogenases (NADP-GDH) encoded by GDH1 and GDH3. Here, we report the relationship between the function of the NADP-GDH and stress-induced apoptosis. Gdh3-null cells showed accelerated chronological aging and hypersusceptibility to thermal and oxidative stress during stationary phase. Upon exposure to oxidative stress, Gdh3-null strains displayed a rapid loss in viability associated with typical apoptotic hallmarks, i.e. reactive oxygen species accumulation, nuclear fragmentation, DNA breakage, and phosphatidylserine translocation. In addition, Gdh3-null cells, but not Gdh1-null cells, had a higher tendency toward GSH depletion and subsequent reactive oxygen species accumulation than did WT cells. GSH depletion was rescued by exogenous GSH or glutamate. The hypersusceptibility of stationary phase Gdh3-null cells to stress-induced apoptosis was suppressed by deletion of GDH2. Promoter swapping and site-directed mutagenesis of GDH1 and GDH3 indicated that the necessity of GDH3 for the resistance to stress-induced apoptosis and chronological aging is due to the stationary phase-specific expression of GDH3 and concurrent degradation of Gdh1 in which the Lys-426 residue plays an essential role.

Significance of the IL-6 pathway in nasal polyposis in Chinese patients.

BACKGROUND: The interleukin-6 (IL-6) pathway is known to be important in Th17 cell differentiation and in the pathology of many inflammatory disorders. However, the significance of the IL-6 pathway in nasal polyposis (NP) in Chinese patients remains unclear. OBJECTIVE: The aim of this study was to evaluate the functions of the IL-6 pathway in NP in Chinese patients. METHODS: The levels of IL-6 pathway components, including IL-6, soluble IL-6 receptor (sIL-6R), phosphoSTAT3 (pSTAT3), and suppressor of cytokine signalling 3 (SOCS3), were assessed. The Th17 milieu was examined by measuring the levels of retinoid acid-related orphan receptor C (RORc) and IL-17A. RESULTS: Levels of IL-6 pathway components, RORc, and IL-17A were significantly higher in both NP groups than in the control(p<0.05). Furthermore, significantly higher levels of pSTAT3, RORc, and IL-17A, and significantly lower levels of SOCS3 were found in the atopic group than in the non-atopic group(P<0.05). IL-6 and sIL-6R levels were not significantly different between the 2 NP groups(P>0.05). pSTAT3 exhibited significantly positive correlations with RORc and IL-17A(P<0.01). CONCLUSIONS: The expression levels of the IL-6 pathway components were significantly higher in NP patients. Moreover, p-STAT3 levels were much higher in the atopic group, and were associated with a more severe Th17 response. These results suggest that the IL-6 pathway may play a crucial role in the pathology of NP in Chinese patients, and atopy may contribute to NP by affecting the IL-6 pathway.

Regulation of transforming growth factor-ß1 activation and expression in the tissue remodeling involved in chronic rhinosinusitis.

Transforming growth factor-ß1 (TGF-ß1) plays a key role in the tissue remodeling processes involved in chronic rhinosinusitis (CRS), with the biological functions of secreted TGF-ß1 regulated by multiple proteins. Among these regulators, latency-associated peptide and latent TGF-ß-binding protein inhibit TGF-ß1 function, whereas different proteases and integrins activate it. Progress in understanding the factors responsible for the bioactivity and expression of TGF-ß1 has revealed that the dysregulation of TGF-ß1 activation and expression is closely associated with the chronic respiratory inflammatory diseases involved in CRS. This review of the regulation of TGF-ß1 activation and expression provides insight into the mechanism responsible for the different CRS subtypes, which will help further the investigation of novel therapy targets for the treatment of CRS.

Enhanced detection of Coxiella burnetii with a complementary locked primer-based real-time PCR method.

BACKGROUND AND OBJECTIVE: Coxiella burnetii is the bacterial causative agent of Q fever in humans. Because Q fever can establish itself with an initial inoculation of fewer than ten C. burnetii cells, a sensitive detection method for C. burnetii infection is needed for early detection. We aimed to evaluate the effectiveness of a complementary locked primer (CLP)-based real-time PCR method for sensitive detection of C. burnetii infection. METHODS: To evaluate the ability of CLPs to enhance the efficiency of the real-time PCR assay for the C. burnetii IS1111 insertion sequence, the mean threshold cycle values from 20 real-time PCR replicates with either CLPs or conventional primers were determined using tenfold serial dilutions (102-108) of purified C. burnetii Nine Mile genomic DNA. In addition, the cross-reactivity between C. burnetii and 31 non-Coxiella species was examined. RESULTS: The CLP-based real-time PCR allowed specific and reliable detection of as few as 59 copies of the IS1111 element present in the genome of C. burnetii, which represents approximately 2.96 genome equivalents or three cells of C. burnetii. These results demonstrate the effectiveness of CLP-based real-time PCR for sensitive detection of C. burnetii infection. CONCLUSION: It can be concluded that the CLP-based real-time PCR assay is a more appropriate method for sensitive detection and quantification of C. burnetii than previously reported methods.