Gene Expression Analyses of Mutant Flammulina velutipes (Enokitake Mushroom) with Clogging Phenomenon

Regulation of proper gene expression is important for cellular and organismal survival, maintenance, and growth. Abnormal gene expression, even for a single critical gene, can thwart cellular integrity and normal physiology to cause diseases, aging, and death. Therefore, gene expression profiling serves as a powerful tool to understand the pathology of diseases and to cure them. In this study, the difference in gene expression in Flammulina velutipes was compared between the wild type (WT) mushroom and the mutant one with clogging phenomenon. Differentially expressed transcripts were screened to identify the candidate genes responsible for the mutant phenotype using the DNA microarray analysis. A total of 88 genes including 60 upregulated and 28 downregulated genes were validated using the realtime quantitative PCR analysis. In addition, proteomic differences between the WT and mutant mushroom were analyzed using two–dimensional gel electrophoresis and matrixassisted laser desorption/ionization-time of flight (MALDI-TOF). Interestingly, the genes identified by these genomic and proteomic analyses were involved in stress response, translation, and energy/sugar metabolism, including HSP70, elongation factor 2, and pyruvate kinase. Together, our data suggest that the aberrant expression of these genes attributes to the mutant clogging phenotype. We propose that these genes can be targeted to foster normal growth in F. velutipes.

Effect of Exercise Intensity on Unfolded Protein Response in Skeletal Muscle of Rat

Endoplasmic reticulum (ER) stress, unfolded protein response (UPR), and mitochondrial biogenesis were assessed following varying intensities of exercise training. The animals were randomly assigned to receive either low- (LIT, n=7) or high intensity training (HIT, n=7), or were assigned to a control group (n=7). Over 5 weeks, the animals in the LIT were exercised on a treadmill with a 10degrees incline for 60 min at a speed of 20 m/min group, and in the HIT group at a speed of 34 m/min for 5 days a week. No statistically significant differences were found in the body weight, plasma triglyceride, and total cholesterol levels across the three groups, but fasting glucose and insulin levels were significantly lower in the exercise-trained groups. Additionally, no statistically significant differences were observed in the levels of PERK phosphorylation in skeletal muscles between the three groups. However, compared to the control and LIT groups, the level of BiP was lower in the HIT group. Compared to the control group, the levels of ATF4 in skeletal muscles and CHOP were significantly lower in the HIT group. The HIT group also showed increased PGC-1alpha mRNA expression in comparison with the control group. Furthermore, both of the trained groups showed higher levels of mitochondrial UCP3 than the control group. In summary, we found that a 5-week high-intensity exercise training routine resulted in increased mitochondrial biogenesis and decreased ER stress and apoptotic signaling in the skeletal muscle tissue of rats.

Ovarian cancer related gene targeting with large circular antisense library / 대한산부인과학회지

OBJECTIVE: The aim of this study is to find out the genes which are related to ovarian cancer cell growth using large circular antisense library. METHODS: Clones for antisense library were uni-directionally sub-cloned into pBS SK (-) vector. LC-antisense molecules were then purified from the culture supernatants of the bacterial competent cells superinfected with M13K07 helper bacteriophages. The LC-antisense library to 240 unigene clone was constructed and utilized in the identification of genes functionally involved in the growth of ovarian cancer cells. RESULTS: The 17 numbers out of the 240 numbers of the antisense library exerted a marked inhibitory effect on the growth of SK-OV 3. CONCLUSION: The putative functional categorization of each gene was then conducted via public databases. These candidates may be used as target genes for drug development or adjuvant of conventional chemotherapeutic drugs.

Effects of TGF-beta1 Ribbon Antisense on CCl4-induced Liver Fibrosis

Ribbon-type antisense oligonucleotide to TGF-beta1(TGF-beta1 RiAS) was designed and tested to prevent or resolve the fibrotic changes induced by CCl4 injection. When Hepa1c1c7 cells were transfected with TGF-beta1 RiAS, the level of TGF-beta1 mRNA was effectively reduced. TGF-beta1 RiAS, mismatched RiAS, and normal saline were each injected to mice via tail veins. When examined for the biochemical effects on the liver, TGF-beta1 mRNA levels were significantly reduced only in the TGF-beta1 RiAS-treated group. The results of immunohistochemical studies showed that TGF-beta1 RiAS prevented the accumulation of collagen and alpha-smooth muscle actin, but could not resolve established fibrosis. These results indicate that ribbon antisense to TGF-beta1 with efficient uptake can effectively prevent fibrosis of the liver.

Insulin Resistance of Skeletal Muscle was Recovered by Leptin Injection in vivo, but not in vitro, in High-fat Diet Fed Rats

We examined the effect of leptin on the insulin resistance in skeletal muscles by measuring the glucose transport. Male Wistar rats were fed with chow or high-fat diets for 30 days. Three days before sacrifice, high-fat fed rats were subcutaneously injected with leptin (1 mg/kg body weight) for 3 days. The glucose transports in the epitrochlearis and soleus muscle were not different among the experimental groups under basal state, however these were decreased significantly in the high fat-diet rats under insulin-stimulation (P< 0.01). Leptin treatment recovered the decreased glucose transport in the epitrochlearis (P< 0.05) and soleus (p=0.08). Triglyceride concentration in the soleus muscle was increased significantly in the high fat-fed rats, compared to chow diet rats (P< 0.01), and it was decreased significantly by leptin treatment (P< 0.01). The glucose transport was measured under basal and 60microU/ml of insulin with or without 50 ng/ml of leptin. Leptin had no direct stimulatory effect on glucose transport under both basal and insulin-stimulated conditions in vitro. These results demonstrate that leptin injection to high fat diet fed rats recovered impaired insulin responsiveness of the skeletal muscles and muscle triglyceride concentration. However, there was no direct stimulatory effect of leptin on insulin sensitivity of the skeletal muscle in vitro.

What is the Key Step in Muscle Fatty Acid Oxidation after Change of Plasma Free Fatty Acids Level in Rats?

The purpose of this study was to discern the critical point in skeletal muscle fatty acid oxidation by changing plasma free fatty acids (FFA) level in rat. In the study, 3 key steps in lipid oxidation were examined after changing plasma FFA level by acipimox. The rates of both palmitate and palmitoyl- carnitine oxidation were decreased by decrease of plasma FFA level, however, carnitine palmitoyl transferase (CPT) 1 activity was not changed, suggesting CPT1 activity may not be involved in the fatty acid oxidation at the early phase of plasma FFA change. In the fasted rats, beta-hydroxy acyl-CoA dehydrogenase (beta-HAD) activity was depressed to a similar extent as palmitate oxidation by a decrease of plasma FFA level. This suggested that beta-oxidation might be an important process to regulate fatty acid oxidation at the early period of plasma FFA change. Citrate synthase activity was not altered by the change of plasma FFA level. In conclusion, the critical step in fatty acids oxidation of skeletal muscles by the change of plasma FFA level by acipimox in fasting rats might be the beta-oxidation step rather than CPT1 and TCA cycle pathways.

Effect of High Fat Diet on Insulin Resistance: Dietary Fat Versus Visceral Fat Mass

The purpose of the present study was to determine whether chronic high-fat diet (HF) induces insulin resistance independently of obesity. We randomly divided 40 rats into two groups and fed them either with a HF or with a high-carbohydrate diet (HC) for 8 weeks. Whole body glucose disappearance rate (Rd) was measured using a euglycemic hyperinsulinemic clamp. Firstly, we defined whether insulin resistance by HF was associated with obesity. Plasma glucose and triglyceride concentrations were significantly increased in HF. Rd was decreased (10.6+/-0.2 vs. 9.1+/-0.2 mg/kg/min in HC and HF, respectively) and the hepatic glucose output rate (HGO) was increased in HF (2.2+/-0.3 vs. 4.5+/-0.2 mg/kg/min in HC and HF, respectively). Rd was significantly correlated with %VF (p<0.01). These results implicate that visceral obesity is associated with insulin resistance induced by HF. In addition, to define whether dietary fat induces insulin resistance regardless of visceral obesity, we compared Rd and HGO between groups 1) after matching %VF in both groups and 2) using an ANCOVA to adjust for %VF. After matching %VF, Rd in HF was significantly decreased by 14% (p<0.001) and HGO was significantly increased by 110% (p<0.001). Furthermore, statistical analyses using an ANCOVA also showed Rd for HF was significantly decreased even after adjusting %VF. In conclusion, we suggest that dietary fat per se could induce insulin resistance in rats fed with chronic HF independently of obesity.

Change in activity of the sympathetic nervous system in diet-induced obese rats

We investigated the change in activity of the sympathetic nervous system (SNS) in high-sucrose diet (HSD)-induced obese rats compared with controls. Power spectral analyses of R-R interval variability were performed to obtain the low frequency (LF, 0.04-0.699 Hz) and high frequency (HF, 0.7-3.0 Hz) powers. The percents of fat mass to body weight (%F/BW) and fat to muscle ratios (F/M) were significantly increased in HSD-fed rats. Plasma glucose, leptin, and triglyceride concentrations in rats fed with HSD were significantly increased. LF in normalized units (LFn), which represents both sympathetic and parasympathetic activities, was significantly increased whereas HF in normalized unit (HFn), which represents parasympathetic activity, was significantly decreased in HSD-fed rats. LF/HF, which represents sympathetic activity, was significantly increased in HSD-fed rats and was correlated with leptin (r=0.549, p<0.023), %F/BW (r=0.513, p<0.035), F/M (r=0.536, p<0.038), and triglyceride (r=0.497, p<0.042). When adjusted for leptin concentrations, however, LF/HF of HSD-fed rats was significantly decreased. In conclusion, HSD-induced obese rats showed increased LF/HF, which was significantly decreased by adjustment for leptin concentrations. We suggest that stimulating effect of leptin on SNS is reduced, which might play a role in induction of obesity by HSD.