Changes in pain perception and hormones pre- and post-kumdo competition

The psychological stress of competition is a powerful stimulus affecting numerous hormones, which in turn change how pain is perceived. This study investigated whether a kumdo (kendo) team competition may be related to changes in hormones and pain. Seventeen healthy male kumdo practitioners participated in this experiment. Pain experiments were conducted by applying noxious stimuli with a thermal stimulator 10 min before a kumdo competition and 30 min post-competition. Serum testosterone, cortisol, beta-endorphin levels, pain thresholds, pain ratings at 48 °C and during blood sampling (sampling pain), anxiety, blood pressure, and heart rate were measured pre- and post-competition. Anxiety, pain threshold, testosterone/cortisol ratio, and blood pressure were significantly higher pre-competition compared to post-competition, while cortisol and pain ratings were significantly lower pre-competition than post-competition. There were significant correlations between the number of previous competitions and testosterone levels both pre-competition and post-competition. In pre-competition measurements, sampling pain increased with an increase in systolic blood pressure, heart rate, and beta-endorphins, and a decrease in age. In post-competition measurements, sampling pain increased with an increase in diastolic blood pressure and a decrease in testosterone levels. These results indicate that severe psychological pre-competition stress was associated with reduced pain ratings, perhaps in order to improve athletic performance. This also suggests that competitors may be at risk of potential injury due to changes in pain perception, and careful consideration should be taken to avoid potential injury before and during competition.     

Mutational biosynthesis of tacrolimus analogues by fkbO deletion mutant of Streptomyces sp. KCTC 11604BP

Tacrolimus (FK506) is an important macrocyclic polyketide showing antifungal and immunosuppressive activities, as well as neuroregenerative properties. Tacrolimus biosynthetic machinery should incorporate the shikimate-derived 4,5-dihydroxycyclohex-1-enecarboxylic acid (DHCHC) as a biosynthetic starter unit into the biosynthetic line of tacrolimus. fkbO is a homologue of rapK encoding chorismatase related to the biosynthesis of starter unit DHCHC from chorismate in the rapamycin biosynthetic gene cluster. FkbO and RapK are good targets for mutational biosynthesis to produce novel analogues of tacrolimus, ascomycin, and rapamycin, which could be important drugs for clinical application in the treatment of cancer and immune and neurodegenerative diseases. To make novel tacrolimus analogues, we prepared an fkbO in-frame deletion mutant, Streptomyces sp. GT110507, from a tacrolimus high producer. We scrutinized the cyclic carboxylic acids that were possibly incorporated instead of DHCHC by precursor-directed mutasynthesis using Streptomyces sp. GT110507 to lead tacrolimus analogues. Among them, trans-4-hydroxycyclohexanecarboxylic acid and 3-hydroxybenzoic acid were successfully incorporated into the tacrolimus backbone, which led to the production of 31-desmethoxytacrolimus and TC-225, respectively. Especially, adding of trans-4-hydroxycyclohexanecarboxylic acid produced a high amount (55 mg/L) of 31-desmethoxytacrolimus. Interestingly, in the rapK mutant, it has been reported that the incorporation of cyclohexanecarboxylic acid (CHC) led to 39-desmethoxy rapamycin. However, in Streptomyces sp. GT110507, CHC is not successfully incorporated. This discrepancy should reflect the differences in the DHCHC biosynthesis mechanism and/or substrate specificity of starter unit loading machineries (FkbP and RapP) of tacrolimus and rapamycin.     

Osteogenic differentiation of human periosteal-derived cells in a three-dimensional collagen scaffold

This study examined the osteogenic differentiation of cultured human periosteal-derived cells grown in a three dimensional collagen-based scaffold. Periosteal explants with the appropriate dimensions were harvested from the mandible during surgical extraction of lower impacted third molar. Periosteal-derived cells were introduced into cell culture. After passage 3, the cells were divided into two groups and cultured for 28 days. In one group, the cells were cultured in two-dimensional culture dishes with osteogenic inductive medium containing dexamethasone, ascorbic acid, and β-glycerophosphate. In the other group, the cells were seeded onto a three-dimensional collagen scaffold and cultured under the same conditions. We examined the bioactivity of alkaline phosphatase (ALP), the RT-PCR analysis for ALP and osteocalcin, and measurements of the calcium content in the periosteal-derived cells of two groups. Periosteal-derived cells were successfully differentiated into osteoblasts in the collagen-based scaffold. The ALP activity in the periosteal-derived cells was appreciably higher in the three-dimensional collagen scaffolds than in the two-dimensional culture dishes. The levels of ALP and osteocalcin mRNA in the periosteal-derived cells was also higher in the three-dimensional collagen scaffolds than in the two-dimensional culture dishes. The calcium level in the periosteal-derived cells seeded onto three-dimensional collagen scaffolds showed a 5.92-fold increase on day 7, 3.28-fold increase on day 14, 4.15-fold increase on day 21, and 2.91-fold increase on day 28, respectively, compared with that observed in two-dimensional culture dishes. These results suggest that periosteal-derived cells have good osteogenic capacity in a three-dimensional collagen scaffold, which provides a suitable environment for the osteoblastic differentiation of these cells.     

Negative regulation of SEK1 signaling by serum- and glucocorticoid-inducible protein kinase 1

Serum- and glucocorticoid-inducible protein kinase 1 (SGK1) has been implicated in diverse cellular activities including the promotion of cell survival. The molecular mechanism of the role of SGK1 in protection against cellular stress has remained unclear, however. We have now shown that SGK1 inhibits the activation of SEK1 and thereby negatively regulates the JNK signaling pathway. SGK1 was found to physically associate with SEK1 in intact cells. Furthermore, activated SGK1 mediated the phosphorylation of SEK1 on serine 78, resulting in inhibition of the binding of SEK1 to JNK1, as well as to MEKK1. Replacement of serine 78 of SEK1 with alanine abolished SGK1-mediated SEK1 inhibition. Oxidative stress upregulated SGK1 expression, and depletion of SGK1 by RNA interference potentiated the activation of SEK1 induced by oxidative stress in Rat2 fibroblasts. Moreover, such SGK1 depletion prevented the dexamethasone-induced increase in SGK1 expression, as well as the inhibitory effects of dexamethasone on paclitaxel-induced SEK1-JNK signaling and apoptosis in MDA-MB-231 breast cancer cells. Together, our results suggest that SGK1 negatively regulates stress-activated signaling through inhibition of SEK1 function.     

Exopolysaccharide production and mycelial growth in an air-lift bioreactor using Fomitopsis pinicola

For effective exopolysaccharide production and mycelial growth by a liquid culture of Fomitopsis pinicola in an air-lift bioreactor, the culture temperature, pH, carbon source, nitrogen source, and mineral source were initially investigated in a flask. The optimal temperature and pH for mycelial growth and exopolysaccharide production were 25degrees C and 6.0, respectively. Among the various carbon sources tested, glucose was found to be the most suitable carbon source. In particular, the maximum mycelial growth and exopolysaccharide production were achieved in 4% glucose. The best nitrogen sources were yeast extract and malt extract. The optimal concentrations of yeast extract and malt extract were 0.5 and 0.1%, respectively. K2HPO4 and MgSO4 x 7H2O were found to be the best mineral sources for mycelial growth and exopolysaccharide production. In order to investigate the effect of aeration on mycelial growth and exopolysaccharide production in an air-lift bioreactor, various aerations were tested for 8 days. The maximum mycelial growth and exopolysaccharide production were 7.9 g/l and 2.6 g/l, respectively, at 1.5 vvm of aeration. In addition, a batch culture in an air-lift bioreactor was carried out for 11 days under the optimal conditions. The maximum mycelial growth was 10.4 g/l, which was approximately 1.7-fold higher than that of basal medium. The exopolysaccharide production was increased with increased culture time. The maximum concentration of exopolysaccharide was 4.4 g/l, which was about 3.3-fold higher than that of basal medium. These results indicate that exopolysaccharide production increased in parallel with the growth of mycelium, and also show that product formation is associated with mycelial growth. The developed model in an air-lift bioreactor showed good agreement with experimental data and simulated results on mycelial growth and exopolysaccharide production in the culture of F pinicola.     

The siRNA-mediated downregulation of N-Ras sensitizes human melanoma cells to apoptosis induced by selective BRAF inhibitors

Previously, we demonstrated that SGEF enhances EGFR stability; however, SGEF-mediated downstream signaling of EGFR is not well understood. Here, we show that SGEF enhances EGF-induced ERK1/2 activation independent of its guanine nucleotide exchange (GEF) activity. We further show that SGEF interacts with Grb2, a critical downstream transducer of EGFR. Surprisingly, we found that interaction of Grb2 to SGEF antagonizes the ability of SGEF to enhance EGF-induced ERK1/2 activation. Taken together, this study reports a novel function of SGEF that excludes GEF and also provides important insights into the complex role of Grb2 in EGFR signal transduction.     

Inhibitory effects of Carpinus tschonoskii leaves extract on CpG-stimulated pro-inflammatory cytokine production in murine bone marrow-derived macrophages and dendritic cells

This report describes the anti-inflammatory effects of MeOH extract from leaves of Carpinus tschonoskii (CE) on primary bone marrow-derived macrophage (BMDMs) and dendritic cells (BMDCs). Primary BMDMs and BMDCs were used for pro-inflammatory cytokine production and Western blot analysis. Human embryonic kidney cell line 293?T (HEK293?T) was used to access NF-κB activity. In all cases, CpG DNA was used to stimulate the cells. The CE (0-150?μg/ml) was treated to BMDMs, BMDCs, and HEK293T cells. CE pre-treatment in CpG-stimulated BMDMs and BMDCs showed a dose-dependent inhibitory effect on pro-inflammatory cytokine (e.g., IL-12 p40, IL-6, and TNF-α) production as compared to non-treated controls. The CE pre-treatment had no significant inhibition on mitogen-activated protein kinases (MAPKs) phosphorylation but strongly inhibited IκBα degradation. In NF-κB reporter gene assay, the CE pre-treatment inhibited NF-κB-dependent luciferase activity in a dose-dependent manner. Taken together, these data suggest that CE has significant inhibitory effect on pro-inflammatory cytokine production and warrant further studies concerning potentials of CE for medicinal uses.