Glycerol-3-phosphate Dehydrogenase Activity Research Articles

Promotion of adipogenesis by neuropeptide Y during the later stages of chicken preadipocyte differentiation.

Neuropeptide Y (NPY) promotes adipogenesis in both birds and mammals, although mechanisms in avians remain unclear. The objective of this study was thus to evaluate effects of NPY on chick preadipocyte proliferation and differentiation. Preadipocytes were treated with 0, 1, 10, or 100 nmol/L NPY and gene expression and cellular proliferation were evaluated at 12, 24, and 48 h. At 12 h posttreatment, mRNA abundance of topoisomerase II alpha (TOP2A), and thioredoxin‐dependent peroxidase 2 was upregulated and NPY was downregulated in response to NPY (0 vs. 100 nmol/L) in preadipocytes. Cells were also treated with NPY during differentiation and harvested at 8, 10, and 12 days postinduction of differentiation. At day 8 postinduction of differentiation, there was increased lipid accumulation (0 vs. 10 and 100 nmol/L), expression of CCAAT/enhancer binding protein β and fatty acid binding protein 4 (FABP4) (0 vs. 100 nmol/L), and sterol regulatory element‐binding protein (0 vs. 10 and 100 nmol/L) mRNA in NPY‐treated cells. The number of proliferating cells decreased on day 8 in response to NPY (0 vs. 10 nmol/L). At day 10, FABP4 and Kruppel‐like factor 7 mRNAs were downregulated (0 vs. 10 and 100 nmol/L, and 100 nmol/L, respectively), and at day 12, TOP2A mRNA was down‐regulated (0 vs. 100 nmol/L) in response to NPY treatment. Activity of glycerol‐3‐phosphate dehydrogenase (G3PDH) was increased on days 10 and 12 in NPY‐treated cells (0 vs. 100 nmol/L). Increased gene expression of proliferation markers in preadipocytes, and during differentiation increased expression of transcription factors and a fatty acid transporter, increased lipid accumulation, and increased activity of G3PDH suggest that NPY may enhance preadipocyte activity, adipogenesis, and promotes lipid accumulation throughout chicken adipocyte differentiation.

Glycerol outflow in Symbiodinium under osmotic and nitrogen stress

In marine nutrient-poor environments, the success of Symbiodinium–cnidarian symbioses depends on the translocation of photosynthetically fixed carbon to the host. However, the mechanisms involved in this translocation are not well understood. Glycerol has been identified in the literature as one of the main photosynthates translocated from symbiont to host. Considering that glycerol is a preferred regulatory osmolyte in many unicellular eukaryotes and exposure of isolated symbionts to host homogenate results in the liberation of glycerol, we investigated the potential role of glycerol and its release in Symbiodinium. We studied the response to high osmolarity in two cultured species of Symbiodinium, examining glycerol production, specific activity of the enzyme glycerol 3-phosphate dehydrogenase and expression of the coding gene. We also assessed the production of glycerol and glucose under osmotic stress and nitrogen depletion. Results showed that cells exposed to high osmolarity conditions induced the synthesis of glycerol, although it was not retained effectively inside cells. In addition, nitrogen depletion also induced the synthesis of glycerol, although values were an order of magnitude lower. Interestingly, a significant decrease in glucose levels was detected in osmotically stressed cultures and under low nitrogen, possibly associated with the storage of carbon. While glycerol is a metabolite induced by osmotic stress, our results do not support its role as osmolyte. We conclude that glycerol may have a role as a sink for reducing power to prevent feedback inhibition of photosynthesis, particularly under low nitrogen, conditions that may be prevalent in the symbiosis.

Two glycerol 3-phosphate dehydrogenase isogenes from Candida versatilis SN-18 play an important role in glycerol biosynthesis under osmotic stress

Two isogenes of glycerol 3-phosphate dehydrogenase (GPD) from Candida versatilis SN-18 were cloned and sequenced. These intronless genes (Cagpd1 and Cagpd2) were both predicted to encode a 378 amino acid polypeptide, and the deduced amino acid sequences mutually showed 76% identity. Interestingly, Cagpd1 and Cagpd2 were located tandemly in a locus of genomic DNA within a 262 bp interval. To our knowledge, this represents a novel instance of isogenic genes relating to glucose metabolism. The stress response element (STRE) was found respectively at -93 to -89 bp upstream of the 5'end of Cagpd1 and -707 to -703 bp upstream of Cagpd2, indicating that these genes are involved in osmotic stress response. In heterologous expression using a gpd1Δgpd2Δ double deletion mutant of Saccharomyces cerevisiae, Cagpd1 and Cagpd2 transformants complemented the function of GPD, with Cagpd2 being much more effective than Cagpd1 in promoting growth and glycerol synthesis. Phylogenetic analysis of the amino acid sequences suggested that Cagpd1p and Cagpd2p are NADP(+)-dependent GPDs (EC 1.1.1.94). However, crude enzyme extract from Cagpd1 and Cagpd2 transformants showed GPD activity with only NAD(+) as cofactor. Hence, both Cagpd1p and Cagpd2p are likely NAD(+)-dependent GPDs (EC 1.1.1.8), similar to GPDs from S. cerevisiae and Candida magnoliae.

Specific features of the lymphocyte enzyme status in newborn infants with the hypotrophic type of intrauterine growth retardation

Objective: to reveal the specific features of the lymphocyte enzyme status in newborn infants with hypotrophic type of intrauterine growth retardation under the conditions of Yakutia. Subjects and methods. A total of 137 full-term newborns (including 28 babies with intrauterine growth retardation) whose parents were Yakutsk newcomers were examined on 1, 3 and 5 days of life. The cytochemical activity of lymphocyte enzymes, by determining the level of and time course of changes in succinate dehydrogenase (SDH), glycerol-3-phosphate dehydrogenase (GPDH), lactate dehydrogenase (LDH) and its aerobic isoenzyme (LDH-H), NADFH2-diaphorase, monoamine oxidase (MAO), and acid phosphatase (AP), were analyzed. Results. It was ascertained that the activity of SDH, GPDH, and LDH was higher on 5 day of life and that of NADFH2-diaphorase was lower in infants with intrauterine growth retardation than in apparently healthy neonates. Desynchronosis of the metabolic pathways was established in the dynamics of early ontogenesis. Conclusion. It is necessary to rationally correct standard treatment regimens, by taking into account the found metabolic features in infants with intrauterine growth retardation under the conditions of Yakutia.

Vitamin A deficiency suppresses high fructose-induced triglyceride synthesis and elevates resolvin D1 levels

Background/AimsVitamin A and its metabolites are known to regulate lipid metabolism. However so far, no study has assessed, whether vitamin A deficiency per se aggravates or attenuates the development of non-alcoholic fatty liver disease (NAFLD). Therefore, here, we tested the impact of vitamin A deficiency on the development of NAFLD. MethodsMale weanling Wistar rats were fed one of the following diets; control, vitamin A-deficient (VAD), high fructose (HFr) and VAD with HFr (VADHFr) of AIN93G composition, for 16weeks, except half of the VAD diet-fed rats were shifted to HFr diet (VAD(s)HFr), at the end of 8th week. ResultsAnimals fed on VAD diet with HFr displayed hypotriglyceridemia (33.5mg/dL) with attenuated hepatic triglyceride accumulation (8.2mg/g), compared with HFr diet (89.5mg/dL and 20.6mg/g respectively). These changes could be partly explained by the decreased activity of glycerol 3-phosphate dehydrogenase (GPDH) and the down-regulation of stearoyl CoA desaturase 1 (SCD1), both at gene and protein levels, the key determinants of triglyceride biosynthesis. On the other hand, n-3 long chain polyunsaturated fatty acid, docosahexaenoic acid and its active metabolite; resolvin D1 (RvD1) levels were elevated in the liver and plasma of VAD diet-fed groups, which was negatively associated with triglyceride levels. All these factors confer vitamin A deficiency-mediated protection against the development of hepatic steatosis, which was also evident from the group shifted from VAD to HFr diet. ConclusionsVitamin A deficiency attenuates high fructose-induced hepatic steatosis, by regulating triglyceride synthesis, possibly through GPDH, SCD1 and RvD1.

P10 - Sirtuins in Stress Response

Selection of broiler chickens for growth has led to increased adipose tissue accretion. To investigate the post-hatch development of adipose tissue, the abdominal, clavicular, and subcutaneous adipose tissue depots were collected from broiler chicks at 4 and 14 days post-hatch. As a percent of body weight, abdominal fat increased (P < 0.001) with age. At day 4, clavicular and subcutaneous fat depots were heavier (P < 0.003) than abdominal fat whereas at day 14, abdominal and clavicular weighed more (P < 0.003) than subcutaneous fat. Adipocyte area and diameter were greater in clavicular and subcutaneous than abdominal fat at 4 and 14 days post-hatch (P < 0.001). Glycerol-3-phosphate dehydrogenase (G3PDH) activity increased (P < 0.001) in all depots from day 4 to 14, and at both ages was greatest in subcutaneous, intermediate in clavicular, and lowest in abdominal fat (P < 0.05). In clavicular fat, peroxisome proliferator-activated receptor-γ (PPARγ), CCAAT/enhancer binding protein (CEBP)α, CEBPβ, fatty acid synthase (FASN), fatty acid binding protein 4 (FABP4), lipoprotein lipase (LPL), neuropeptide Y (NPY), and NPY receptor 5 (NPYR5) mRNA increased and NPYR2 mRNA decreased from day 4 to 14 (P < 0.001). Thus, there are site-specific differences in broiler chick adipose development, with larger adipocytes and greater G3PDH activity in subcutaneous fat at day 4, more rapid growth of abdominal fat, and clavicular fat intermediate for most traits. Adipose tissue expansion was accompanied by changes in gene expression of adipose-associated factors.

Broiler chicken adipose tissue dynamics during the first two weeks post-hatch

Selection of broiler chickens for growth has led to increased adipose tissue accretion. To investigate the post-hatch development of adipose tissue, the abdominal, clavicular, and subcutaneous adipose tissue depots were collected from broiler chicks at 4 and 14days post-hatch. As a percent of body weight, abdominal fat increased (P<0.001) with age. At day 4, clavicular and subcutaneous fat depots were heavier (P<0.003) than abdominal fat whereas at day 14, abdominal and clavicular weighed more (P<0.003) than subcutaneous fat. Adipocyte area and diameter were greater in clavicular and subcutaneous than abdominal fat at 4 and 14days post-hatch (P<0.001). Glycerol-3-phosphate dehydrogenase (G3PDH) activity increased (P<0.001) in all depots from day 4 to 14, and at both ages was greatest in subcutaneous, intermediate in clavicular, and lowest in abdominal fat (P<0.05). In clavicular fat, peroxisome proliferator-activated receptor-γ (PPARγ), CCAAT/enhancer binding protein (CEBP)α, CEBPβ, fatty acid synthase (FASN), fatty acid binding protein 4 (FABP4), lipoprotein lipase (LPL), neuropeptide Y (NPY), and NPY receptor 5 (NPYR5) mRNA increased and NPYR2 mRNA decreased from day 4 to 14 (P<0.001). Thus, there are site-specific differences in broiler chick adipose development, with larger adipocytes and greater G3PDH activity in subcutaneous fat at day 4, more rapid growth of abdominal fat, and clavicular fat intermediate for most traits. Adipose tissue expansion was accompanied by changes in gene expression of adipose-associated factors.

Expression of Chlamydomonas reinhardtii CrGPDH2 and CrGPDH3 cDNAs in yeast reveals that they encode functional glycerol-3-phosphate dehydrogenases involved in glycerol production and osmotic stress tolerance

Glycerol-3-phosphate dehydrogenase (GPDH) catalyzes the conversion of dihydroxyacetone phosphate (DHAP) to glycerol-3-phosphate (G3P) and plays a central role in the synthesis of glycerol and triacylglycerides (TAGs). Osmotic stress has been shown to induce the accumulation of glycerol and TAGs in the green microalga Chlamydomonas reinhardtii. In a previous study, we identified three GPDH homologs (CrGPDH1, CrGPDH2, and CrGPDH3) in this microalga. We found that CrGPDH2 and CrGPDH3 were expressed in response to 200 mM NaCl treatment, suggesting that these two genes play roles in glycerol and TAGs synthesis and in osmotic stress tolerance. In this study, we report on the functional characterization of CrGPDH2 and CrGPDH3. A concentration of NaCl as low as 5 mM for 5 min was sufficient to induce the expressions of both genes. We mapped the cDNA ends of CrGPDH2 and CrGPDH3 using RLM-RACE and cloned their full-length cDNAs. The expression of these two cDNAs in the Saccharomyces cerevisiae gpd1Δgpd2Δ double mutant confirmed that both CrGPDH2 and CrGPDH3 have GPDH activity. The genetic complementation analysis revealed that CrGPDH2 and CrGPDH3 were able to restore glycerol production and rescue the salt sensitivity of this mutant. Compared with CrGPDH3, CrGPDH2 conferred higher glycerol production and greater salt tolerance when expressed in the gpd1Δgpd2Δ double mutant. Together, these findings show that CrGPDH2 and CrGPDH3 encode functional homologs of the S. cerevisiae GPD1 gene that is involved in glycerol synthesis and osmotic stress tolerance.

Carnosic Acid Inhibits Lipid Accumulation in 3T3-L1 Adipocytes Through Attenuation of Fatty Acid Desaturation.

Background:Excess body fat accumulation contributes to the development of metabolic disorders that can cause adverse health effects. Carnosic acid (CA), a major bioactive component of rosemary (Rosemarinus officinalis), has been suggested to possess anti-adipogenic properties. The present study was conducted to elucidate the mechanism underlying the anti-adipogenic effects of CA.Methods:3T3-L1 pre-adipocytes were treated with CA (0.1, 1, and 10 μM) from day 0 to day 8 of differentiation. On day 8, biochemical markers of lipid accumulation and the degree of fatty acid desaturation were measured.Results:Oil Red O staining results, triglyceride (TG) accumulation, and glycerol 3-phosphate dehydrogenase activity suggested that CA significantly inhibited lipid accumulation in 3T3-L1 adipocytes. CA significantly decreased mRNA expression of peroxisome proliferator-activated receptor-γ, sterol regulatory element-binding protein 1, and CCAAT/enhancer binding protein-α in a dose-dependent manner. Moreover, it decreased the ratio of both C16:1/C16:0 and C18:1/C18:0, with reduced expression of stearoyl CoA desaturase 1 mRNA and protein.Conclusions:These results suggest that CA efficiently suppressed adipogenesis in 3T3-L1 adipocytes and its action, at least in part, is associated with the downregulation of adipogenesis-related genes and the fatty acid composition of TG accumulated in adipocytes.

Traditional medicine yanggyuksanhwa-tang inhibits adipogenesis and suppresses proliferator-activated receptor-gamma expression in 3T3-L1 cells.

Background:Yanggyuksanhwa-tang (YGSHT) is a specific traditional Korean herbal formula for Soyangin according to Sasang constitutional philosophy. Although its biological activities against inflammation and cerebral infarction have been reporting, there is no information about the adipogenic activity of YGSHT. In the present study, we investigated the anti-adipogenic activity of YGSHT to evaluate effects of YGSHT on adipogenesis in vitro.Materials and Methods:Using 3T3-L1 preadipocytes, we induced the cellular differentiation into adipocytes by adding insulin. Anti-adipogenic activity of YGSHT was measured by oil red O staining, triglyceride assay, glycerol-3-phosphate dehydrogenase (GPDH) activity test, and leptin assay.Results:YGSHT extract had no significant cytotoxicity in preadipocytes or differentiated adipocytes. YGSHT reduced the number of lipid droplets and content of triglyceride in adipose cells. YGSHT also significantly inhibited GPDH activity and decreased leptin production compared with control adipocytes. Down-regulation of peroxisome proliferator-activated receptor-gamma (PPAR-γ) expression at the messenger RNA level was observed in YGSHT-treated adipocytes.Conclusion:Taken together, our data suggest that YGSHT has potential as an anti-obesity drug candidate.

Soluble extract of soybean fermented with Aspergillus oryzae GB107 inhibits fat accumulation in cultured 3T3-L1 adipocytes.

BACKGROUND/OBJECTIVESThis study was conducted to investigate the effects of fermented soybean (FS) extract on adipocyte differentiation and fat accumulation using cultured 3T3-L1 adipocytes.MATERIALS/METHODS3T3-L1 adipocytes were treated with FS and nonfermented soybean (NFS) extract during differentiation for 10 days in vitro. Oil red O staining was performed and glycerol-3-phosphate dehydrogenase (GPDH) activity was measured for analysis of fat accumulation. Expressions of adipogenic genes were measured.RESULTSSoluble extract of soybean fermented with Aspergillus oryzae GB107 contained higher levels of low-molecular-weight protein than conventional soybean protein did. FS extract (50 µg/ml) inhibited adipocyte differentiation and fat accumulation during differentiation of 3T3-L1 preadipocytes for 10 days in vitro. Significantly lower GPDH activity was observed in differentiated adipocytes treated with the FS extract than those treated with NFS extract. Treatment with FS extract resulted in decreased expression levels of leptin, adiponectin, and adipogenin genes, which are associated with adipogenesis.CONCLUSIONSThis report is the first to demonstrate that the water-soluble extract from FS inhibits fat accumulation and lipid storage in 3T3-L1 adipocytes. Thus, the soybean extract fermented with A. oryzae GB107 could be used to control lipid accumulation in adipocytes.

Effect of high hydrostatic pressure extract of fresh ginseng on adipogenesis in 3T3-L1 adipocytes.

Red ginseng is produced by steaming and drying fresh ginseng. Through this processing, chemical compounds are modified, and then biological activities are changed. In the food-processing industry, high hydrostatic pressure (HHP) has become an alternative to heat processing to make maximum use of bioactive compounds in food materials. This study comparatively investigated the anti-adipogenic effects of water extract of red ginseng (WRG) and high hydrostatic pressure extract of fresh ginseng (HPG) in 3T3-L1 adipocytes. Both WRG and HPG inhibited the accumulation of intracellular lipids and triglycerides, and the activity of glycerol-3-phosphate dehydrogenase (GPDH), a key enzyme in triglyceride biosynthesis. Intracellular lipid content and GPDH activity were significantly lower in the HPG group compared to the WRG group. In addition, mRNA expression of adipogenic genes, including CEBP-α, SREBP-1c and aP2, were lower in HPG-treated cells compared to WRG-treated cells. HPG significantly increased the activity of AMPK, and WRG did not. Results suggested that HPG may have superior beneficial effects on the inhibition of adipogenesis compared with WRG. The anti-adipogenic effects of HPG were partially associated with the inhibition of GPDH activity, suppression of adipogenic gene expression and activation of AMPK in 3T3-L1 adipocytes.

Effect of Ganoderma applanatum mycelium extract on the inhibition of adipogenesis in 3T3-L1 adipocytes.

Ganoderma applanatum (GA) and related fungal species have been used for over 2000 years in China to prevent and treat various human diseases. However, there is no critical research evaluating the functionality of GA grown using submerged culture technology. This study aimed to evaluate the effects of submerged culture GA mycelium (GAM) and its active components (protocatechualdehyde [PCA]) on preadipocyte differentiation of 3T3-L1 cells. Mouse-derived preadipocyte 3T3-L1 cells were treated with differentiation inducers in the presence or absence of GAM extracts. We determined triglyceride accumulations, glycerol-3-phosphate dehydrogenase (GPDH) activities, and differentiation makers. PCA, the active component of GAM extract, was also used to treat 3T3-L1 cells. The MTT assay showed that the GAM extract (0.01-1 mg/mL) was not toxic to 3T3-L1 preadipocyte. Treatment of cells with GAM extracts and its active components significantly decreased the GPDH activity and lipid accumulation, a marker of adipogenesis, in a dose-dependent manner. Western blot analysis results showed that the protein expression levels of peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer-binding protein α (C/EBPα), and sterol regulatory element-binding protein 1 (SREBP1) were inhibited by the GAM extract. In addition, adipogenic-specific genes such as perilipin, fatty acid synthase (FAS), fatty acid transport protein 1 (FATP1), and fatty acid-binding protein 4 (FABP4) decreased in a dose-dependent manner. Quantitative high-performance liquid chromatography analysis showed that the GAM extract contained 1.14 mg/g PCA. GAM extracts suppressed differentiation of 3T3-L1 preadipocytes, in part, through altered regulation of PPARγ, C/EBPα, and SREBP1. These results suggest that GAM extracts and PCA may suppress adipogenesis by inhibiting differentiation of preadipocytes.

Effect of growth hormone on the differentiation of bovine preadipocytes into adipocytes and the role of the signal transducer and activator of transcription 5b1

We evaluated the effect of GH on the differentiation of primary bovine preadipocytes into adipocytes. Bovine preadipocytes, derived from adipose tissue explants, were induced to differentiate into adipocytes in the presence or absence of recombinant bovine GH. The differentiation status of adipocytes was assessed by Oil Red O staining and by measuring the activity of glycerol-3-phosphate dehydrogenase (G3PDH) and the rate of acetate incorporation. Fewer preadipocytes became adipocytes in the presence of GH than in the absence of GH; adipocytes formed in the presence of GH had lower G3PDH activity and lower rate of acetate incorporation than those formed without GH treatment (P < 0.05). These data suggest an inhibitory effect of GH on the differentiation of bovine preadipocytes into adipocytes. Growth hormone decreased the expression of C/EBPα and PPARγ mRNA in bovine adipocytes (P < 0.05). Because C/EBPα and PPARγ are the master regulators of adipocyte differentiation, this data suggests that GH might inhibit the differentiation of bovine preadipocytes into adipocytes by inhibiting the expression of C/EBPα and/or PPARγ. Because the signal transducer and activator of transcription 5 (STAT5) is a major component of signaling from the GH receptor, we next determined the potential role of STAT5 in GH inhibition of bovine adipocyte differentiation. Overexpression of a constitutively active form of STAT5b (STAT5bCA) in bovine preadipocytes through adenoviral transduction mimicked the effects of GH on the formation of lipid-containing adipocytes, G3PDH activity, and acetate incorporation rate. Overexpression of STAT5bCA was associated with decreased expression of C/EBPα mRNA (P < 0.05) but not that of PPARγ mRNA in bovine adipocytes. These results support a role of STAT5b in mediating GH inhibition of C/EBPα expression but not that of PPARγ expression in bovine preadipocytes. Overall, the present study suggests that GH may inhibit adipose growth in cattle in part by inhibiting adipogenesis and that GH inhibits the differentiation of bovine preadipocytes to adipocytes through STAT5b-dependent inhibition of C/EBPα expression and STAT5b-independent inhibition of PPARγ expression.

Quercetin-rich onion peel extract suppresses adipogenesis by down-regulating adipogenic transcription factors and gene expression in 3T3-L1 adipocytes

Onion peel contains a high amount of quercetin, which has been reported to have anti-cholesterol, antithrombotic and insulin-sensitizing properties. This study aimed to elucidate the anti-adipogenic effects of quercetin-rich onion peel extract (OPE) and to compare it with commercially available quercetin using 3T3-L1 preadipocytes. Without affecting cell viability, both OPE and quercetin averted adipogenesis, as characterized by dose-dependent decreases in intracellular triglyceride content and glycerol 3-phosphate dehydrogenase activity, but the effect was more pronounced with OPE than with quercetin. The mRNA expression levels of key adipogenic genes such as PPARγ, C/EBPα, FABP4, aP2 and LPL were decreased in a dose-dependent manner by both OPE and quercetin. The results indicate that OPE treatment significantly prevents intracellular lipid accumulation via hyperactivation of genes regulating lipolysis as compared with quercetin alone.

The JNK-Like MAPK KGB-1 of Caenorhabditis Elegans Promotes Reproduction, Lifespan, and Gene Expressions for Protein Biosynthesis and Germline Homeostasis but Interferes with Hyperosmotic Stress Tolerance

Aims: This study focused on the role of the JNK-like MAPK (mitogen-activated protein kinase) KGB-1 (kinase, GLH-binding 1) for osmoprotection and other vital functions. Methods: We mapped KGB-1 expression patterns and determined lifespan, reproduction and survival rates as well as changes in body volume, motility, and GPDH (glycerol-3-phosphate dehydrogenase) activity for glycerol production in wildtype (WT), different signaling mutants (including a kgb-1 deletion mutant, kgb-1∆) and RNAi-treated worms under control and hyperosmotic conditions. KGB-1-mediated gene expressions were studied, for instance, by RNA Sequencing, with the resulting transcriptome data analyzed using orthology-based approaches. Results: Surprisingly, mutation/RNAi of kgb-1 and fos-1 (gene for an AP-1, activator protein 1, element) significantly promoted hyperosmotic resistance, even though hyperosmotic GPDH activity was higher in WT than in kgb-1∆. KGB-1 and moderate hyperosmolarity promoted and severe hyperosmolarity repressed kgb-1, fos-1, and jun-1 (gene for another AP-1 element) expression. Transcriptome profiling revealed, for instance, down-regulated genes for protein biosynthesis and up-regulated genes for membrane transporters in kgb-1∆ and up-regulated genes for GPDH-1 or detoxification in WT, with the latter indicating cellular damage and less effective osmoprotection in WT. Conclusion: KGB-1 promotes reproduction and lifespan and fosters gene expressions for AP-1 elements, protein biosynthesis, and balanced gametogenesis, but inhibits expressions for membrane transporters perhaps in order to control energy consumption. Reduced protein biosyntheses and enhanced membrane transports in kgb-1∆ most likely contribute to the high hyperosmotic tolerance of the mutant by easing the burden of the existing chaperone machinery and promoting regulatory volume increases upon hyperosmotic stress.

Topical prostaglandin analogue drugs inhibit adipocyte differentiation.

PurposeTo investigate the effects of topical prostaglandin analogue drugs on the differentiation of adipocytes.MethodsDifferentiation of 3T3-L1 preadipocytes was induced with isobutylmethylxanthine, dexamethasone, and insulin. 3T3-L1 cells were exposed to 0.008, 0.08, 0.2 µM of latanoprost and travoprost. Reverse transcription polymerase chain reaction for mRNA expression of lipoprotein lipase and peroxisome proliferator-activated receptor γ 2 (PPARγ2), and glycerol-3-phosphate dehydrogenase (G3PDH) assays were performed to examine the effects on early and late differentiation, respectively. Also, glycerol assays were done to evaluate the effect of prostaglandin analogues on lipolysis after differentiation.ResultsBoth prostaglandin analogues inhibited differentiation of preadipocytes. Topical prostaglandin analogues significantly decreased G3PDH activity, a marker of late differentiation. However, topical prostaglandin analogues did not change mRNA expressions of lipoprotein lipase and PPARγ2, markers of early differentiation. The activities of the early markers of differentiation were not changed significantly before and after growth arrest. Compared to latanoprost, travoprost decreased G3PDH activity more significantly (p < 0.05). Both prostaglandin analogues did not affect the lipolysis of differentiated adipocytes (p > 0.05).ConclusionsProstaglandin analogues display an inhibitory effect on the differentiation of adipocytes when the cells start to differentiate especially in the late stage of differentiation. Thus, commercial topical prostaglandin analogues may decrease the fat contents of eyelids.

Suppression of adipogenic differentiation by muscle cell‐induced decrease in genes related to lipogenesis in muscle and fat co‐culture system

Intercellular signalling communication between adipose and muscle tissue has been investigated. To test the effect of muscle cells on adipogenic gene expression, we utilised an in vitro co-culture system, in which fat (3T3-L1) and muscle (L-6) cells were physically separated but chemically exposed each other via insert with 0.4 µm porous membrane. When 3T3-L1 and L-6 cells reached at 80 and 40% confluence, respectively in separate wells, L-6 cells grown in insert were transferred onto 6-well plates where 3T3-L1 cells were being grown. When both cells were fully differentiated in co-culture plates, morphology of 3T3-L1 was examined by staining with Oil-red-O. Activity of glycerol-3-phosphate dehydrogenase (GPDH) and adipogenic gene expression including lipoprotein lipase (LPL), adipsin, GPDH, peroxisome proliferator-activated receptor-γ (PPARγ) and CCAAT/enhancer binding protein (C/EBPα) were analysed. The presence of muscle cells during preadipocyte differentiation inhibited (P < 0.05) lipogenesis by suppressing lipogenic gene expression including LPL, adipsin and GPDH. Furthermore, GPDH activity was also decreased (P < 0.05) in 3T3-L1 cells by the presence of L-6 cells. These results suggest that presence of muscle cells suppresses adipogenic differentiation by inhibiting the adipogenic gene expression and GPDH activity in the muscle and fat cell co-culture system.

Diaphragm Muscle Remodeling in a Rat Model of Chronic Intermittent Hypoxia

Respiratory muscle remodeling occurs in human sleep apnea--a common respiratory disorder characterized by chronic intermittent hypoxia (CIH) due to recurrent apnea during sleep. We sought to determine if CIH causes remodeling in rat sternohyoid (upper airway dilator) and diaphragm muscles. Adult male Wistar rats were exposed to CIH (n=8), consisting of 90 sec of hypoxia (5% at the nadir; SaO₂ ~80%)/90 sec of normoxia, 8 hr per day, for 7 consecutive days. Sham animals (n=8) were exposed to alternating air/air cycles in parallel. The effect of CIH on myosin heavy-chain (MHC) isoform (1, 2a, 2x, 2b) distribution, sarcoplasmic reticulum calcium ATPase (SERCA) isoform distribution, succinate dehydrogenase activity, glycerol phosphate dehydrogenase activity, and Na⁺/K⁺ ATPase pump content was determined. Sternohyoid muscle structure was unaffected by CIH treatment. CIH did not alter oxidative/glycolytic capacity or the Na⁺/K⁺-ATPase pump content of the diaphragm. CIH significantly increased the areal density of MHC 2b fibers in the rat diaphragm, and this was associated with a shift in SERCA proteins from SERCA2 to SERCA1. We conclude that CIH causes a slow-to-fast fiber transition in the rat diaphragm after just 7 days of treatment. Respiratory muscle functional remodeling may drive aberrant functional plasticity such as decreased muscle endurance, which is a feature of human sleep apnea.

Differential expression of glycerol-3-phosphate dehydrogenase isoforms in flight muscles of the Chagas disease vector Triatoma infestans (Hemiptera, Reduviidae).

Flight muscles of Triatoma infestans have two glycerol-3-phosphate dehydrogenase (GPDH) isoforms: GPDH-1 is involved in flight metabolism and GPDH-2 provides lipid precursors. Total GPDH activity was greater in the natural population and almost only due to GPDH-1. Different expression and activity observed between GPDH isoforms in the natural population and the first laboratory generation was not detected in the second laboratory generation. This pattern may be caused by gradual adaptation to laboratory nutritional conditions. During development, the expression of GPDH-2 increased with a longer time of intake, which would imply an increment in lipid biosynthesis. The GPDH-1 transcript predominated with respect to that of GPDH-2 in the lower nutritional condition, suggesting the necessity of insects to fly during this nutritional status. The transcriptional pattern showed a delay at 22°C. The isoforms activities and transcript patterns in flight muscles suggest transcriptional adaptation to metabolic requirements originated by alternative splicing.