Increased mRNA Abundance Research Articles

Cortisol modulates the expression of cytokines and suppressors of cytokine signaling (SOCS) in rainbow trout hepatocytes

Although liver is a key target for corticosteroid action, its role in immune function is largely unknown. We tested the hypothesis that stress levels of cortisol down regulate immune-relevant genes in rainbow trout (Oncorhynchus mykiss) liver. Hepatocytes were treated with lipopolysaccharide (LPS) for 24h either in the presence or absence of cortisol. LPS stimulated heat shock protein 70 expression, enhanced glycolytic capacity, and reduced glucose output. LPS stimulated mRNA abundance of cytokines and serum amyloid protein A (SAA), while suppressors of cytokine signaling (SOCS)-3 was reduced. Cortisol increased mRNA abundances of IL-1β, SOCS-1 and SOCS-2, while inhibiting either basal or LPS-stimulated IL-8, TNF α2 and SAA. These cortisol-mediated effects were rescued by Mifepristone, a glucocorticoid receptor antagonist. Altogether, cortisol modulates the molecular immune response in trout hepatocytes. The upregulation of SOCS-1 and SOCS-2 by cortisol may be playing a key role in suppressing cytokine signaling and the associated inflammatory response.

Efficient subtraction of insect rRNA prior to transcriptome analysis of Wolbachia-Drosophila lateral gene transfer

BackgroundNumerous methods exist for enriching bacterial or mammalian mRNA prior to transcriptome experiments. Yet there persists a need for methods to enrich for mRNA in non-mammalian animal systems. For example, insects contain many important and interesting obligate intracellular bacteria, including endosymbionts and vector-borne pathogens. Such obligate intracellular bacteria are difficult to study by traditional methods. Therefore, genomics has greatly increased our understanding of these bacteria. Efficient subtraction methods are needed for removing both bacteria and insect rRNA in these systems to enable transcriptome-based studies.FindingsA method is described that efficiently removes >95% of insect rRNA from total RNA samples, as determined by microfluidics and transcriptome sequencing. This subtraction yielded a 6.2-fold increase in mRNA abundance. Such a host rRNA-depletion strategy, in combination with bacterial rRNA depletion, is necessary to analyze transcription of obligate intracellular bacteria. Here, transcripts were identified that arise from a lateral gene transfer of an entire Wolbachia bacterial genome into a Drosophila ananassae chromosome. In this case, an rRNA depletion strategy is preferred over polyA-based enrichment since transcripts arising from bacteria-to-animal lateral gene transfer may not be poly-adenylated.ConclusionsThis enrichment method yields a significant increase in mRNA abundance when poly-A selection is not suitable. It can be used in combination with bacterial rRNA subtraction to enable experiments to simultaneously measure bacteria and insect mRNA in vector and endosymbiont biology experiments.

Three Acyltransferases and Nitrogen-responsive Regulator Are Implicated in Nitrogen Starvation-induced Triacylglycerol Accumulation in Chlamydomonas

Algae have recently gained attention as a potential source for biodiesel; however, much is still unknown about the biological triggers that cause the production of triacylglycerols. We used RNA-Seq as a tool for discovering genes responsible for triacylglycerol (TAG) production in Chlamydomonas and for the regulatory components that activate the pathway. Three genes encoding acyltransferases, DGAT1, DGTT1, and PDAT1, are induced by nitrogen starvation and are likely to have a role in TAG accumulation based on their patterns of expression. DGAT1 and DGTT1 also show increased mRNA abundance in other TAG-accumulating conditions (minus sulfur, minus phosphorus, minus zinc, and minus iron). Insertional mutants, pdat1-1 and pdat1-2, accumulate 25% less TAG compared with the parent strain, CC-4425, which demonstrates the relevance of the trans-acylation pathway in Chlamydomonas. The biochemical functions of DGTT1 and PDAT1 were validated by rescue of oleic acid sensitivity and restoration of TAG accumulation in a yeast strain lacking all acyltransferase activity. Time course analyses suggest than a SQUAMOSA promoter-binding protein domain transcription factor, whose mRNA increases precede that of lipid biosynthesis genes like DGAT1, is a candidate regulator of the nitrogen deficiency responses. An insertional mutant, nrr1-1, accumulates only 50% of the TAG compared with the parental strain in nitrogen-starvation conditions and is unaffected by other nutrient stresses, suggesting the specificity of this regulator for nitrogen-deprivation conditions.

Onion peel extract increases hepatic low-density lipoprotein receptor and ATP-binding cassette transporter A1 messenger RNA expressions in Sprague-Dawley rats fed a high-fat diet

In the present study, we hypothesized that onion peel extract (OPE) alters hepatic gene expression to improve blood cholesterol profiles. To investigate the effect of OPE to test our hypothesis, Sprague-Dawley rats were fed ad libitum for 8 weeks with the control, high-fat diet (HFD) or the high-fat diet with 0.2% OPE supplementations (HFD + OPE). Messenger RNA (mRNA) levels of genes in cholesterol metabolism and fatty acid metabolism were examined by semiquantitative reverse transcriptase polymerase chain reaction. The OPE in HFD reverted high fat-induced reduction in mRNA levels of sterol regulatory element-binding protein-2, low-density lipoprotein receptor, and hydroxyl-3-methylglutaryl coenzyme reductase genes in the liver comparable with the levels of the control group. Onion peel extract slightly increased stearoyl-coA desaturase 1 (SCD-1) expression compared with high-fat feeding. However, sterol regulatory element-binding protein-1c and fatty acid synthase were not affected by high-fat or OPE feeding. Onion peel extract also enhanced expression of ATP-binding cassette transporter A1, peroxisome proliferator-activated receptor γ2 and scavenger receptor class B type I genes when compared with high-fat feeding. However, OPE did not influence high fat-triggered changes in apolipoprotein A1 mRNA levels and liver X receptor α were not affected by either high-fat or OPE feeding. Our results suggest that OPE changes the expression of genes associated with cholesterol metabolism in favor of lowering blood low-density lipoprotein cholesterol and enhancing high-density lipoprotein cholesterol through increasing mRNA abundance of low-density lipoprotein receptor and ATP-binding cassette transporter A1 genes.

Deficiency of ACE2 in Bone-Marrow-Derived Cells Increases Expression of TNF-αin Adipose Stromal Cells and Augments Glucose Intolerance in Obese C57BL/6 Mice

Deficiency of ACE2 in macrophages has been suggested to promote the development of an inflammatory M1 macrophage phenotype. We evaluated effects of ACE2 deficiency in bone-marrow-derived stem cells on adipose inflammation and glucose tolerance in C57BL/6 mice fed a high fat (HF) diet. ACE2 activity was increased in the stromal vascular fraction (SVF) isolated from visceral, but not subcutaneous adipose tissue of HF-fed mice. Deficiency of ACE2 in bone marrow cells significantly increased mRNA abundance of F4/80 and TNF-α in the SVF isolated from visceral adipose tissue of HF-fed chimeric mice, supporting increased presence of inflammatory macrophages in adipose tissue. Moreover, deficiency of ACE2 in bone marrow cells modestly augmented glucose intolerance in HF-fed chimeric mice and increased blood levels of glycosylated hemoglobin. In summary, ACE2 deficiency in bone marrow cells promotes inflammation in adipose tissue and augments obesity-induced glucose intolerance.

Permeability properties of the teleost gill epithelium under ion-poor conditions

Permeability properties of the goldfish gill epithelium were examined in vivo and in vitro following exposure to ion-poor water (IPW) conditions. In gill tissue of IPW-acclimated goldfish, transcript abundance of tight junction (TJ) proteins occludin, claudin-b, -d, -e, -h, -7, and -8d increased, whereas ZO-1 and claudin 12 mRNA decreased and claudin-c was unaltered. In association with these changes, TJ depth increased among gill pavement cells (PVCs) and gill PVCs and mitochondria-rich cells (MRCs). PVC and MRC gill cell fractions were isolated using Percoll. Transcripts encoding for occludin, claudin-b, -c, -d, -e, -h, -7, -8d, -12, and ZO-1 were present in both fractions. After IPW acclimation, occludin, claudin-b and -e, and ZO-1 mRNA abundance increased in both fractions. In contrast, claudin-8d mRNA abundance increased in PVCs only while claudin-h decreased in MRCs. Gill permeability was examined using primary cultured goldfish PVC epithelia supplemented with serum derived from IPW-acclimated goldfish. IPW serum supplementation increased transepithelial resistance, reduced [(3)H]PEG-4000 permeability, and enhanced epithelial integrity during in vitro IPW exposure. IPW serum increased mRNA abundance of occludin, claudin-8d and -e in vitro. Using small interfering RNA, we found that occludin abundance was decreased in cultured gill epithelia, resulting in an increase in [(3)H]PEG-4000 flux. As occludin increased in the gills of IPW-acclimated fish as well as cultured gill epithelia exposed to IPW serum, results suggest that occludin is a barrier-forming TJ protein in fish gill epithelia. These studies support the idea that TJ proteins play an important role in regulating gill permeability in IPW.

Is There a Classical Nonsense-Mediated Decay Pathway in Trypanosomes?

In many eukaryotes, messenger RNAs with premature termination codons are destroyed by a process called “nonsense-mediated decay”, which requires the RNA helicase Upf1 and also, usually, an interacting factor, Upf2. Recognition of premature termination codons may rely on their distance from either a splice site or the polyadenylation site, and long 3′-untranslated regions can trigger mRNA decay. The protist Trypanosoma brucei relies heavily on mRNA degradation to determine mRNA levels, and 3′-untranslated regions play a major role in control of mRNA decay. We show here that trypanosomes have a homologue of Upf1, TbUPF1, which interacts with TbUPF2 and (in an RNA-dependent fashion) with poly(A) binding protein 1, PABP1. Introduction of a premature termination codon in either an endogenous gene or a reporter gene decreased mRNA abundance, as expected for nonsense-mediated decay, but a dependence of this effect on TbUPF1 could not be demonstrated, and depletion of TbUPF1 by over 95% had no effect on parasite growth or the mRNA transcriptome. Further investigations of the reporter mRNA revealed that increases in open reading frame length tended to increase mRNA abundance. In contrast, inhibition of translation, either using 5′-secondary structures or by lengthening the 5′-untranslated region, usually decreased reporter mRNA abundance. Meanwhile, changing the length of the 3′-untranslated region had no consistent effect on mRNA abundance. We suggest that in trypanosomes, translation per se may inhibit mRNA decay, and interactions with multiple RNA-binding proteins preclude degradation based on 3′-untranslated region length alone.

Polychlorinated biphenyl 77 augments angiotensin II-induced atherosclerosis and abdominal aortic aneurysms in male apolipoprotein E deficient mice

Infusion of angiotensin II (AngII) to hyperlipidemic mice augments atherosclerosis and causes formation of abdominal aortic aneurysms (AAAs). Each of these AngII-induced vascular pathologies exhibit pronounced inflammation. Previous studies demonstrated that coplanar polychlorinated biphenyls (PCBs) promote inflammation in endothelial cells and adipocytes, two cell types implicated in AngII-induced vascular pathologies. The purpose of this study was to test the hypothesis that administration of PCB77 to male apolipoprotein E (ApoE) −/− mice promotes AngII-induced atherosclerosis and AAA formation. Male ApoE−/− mice were administered vehicle or PCB77 (49 mg/kg, i.p.) during week 1 and 4 (2 divided doses/week) of AngII infusion. Body weights and total serum cholesterol concentrations were not influenced by administration of PCB77. Systolic blood pressure was increased in AngII-infused mice administered PCB77 compared to vehicle (156 ± 6 vs 137 ± 5 mmHg, respectively). The percentage of aortic arch covered by atherosclerotic lesions was increased in AngII-infused mice administered PCB77 compared to vehicle (2.0 ± 0.4 vs 0.9 ± 0.1%, respectively). Lumen diameters of abdominal aortas determined by in vivo ultrasound and external diameters of excised suprarenal aortas were increased in AngII-infused mice administered PCB77 compared to vehicle. In addition, AAA incidence increased from 47 to 85% in AngII-infused mice administered PCB77. Adipose tissue in close proximity to AAAs from mice administered PCB77 exhibited increased mRNA abundance of proinflammatory cytokines and elevated expression of components of the renin-angiotensin system (angiotensinogen, angiotensin type 1a receptor (AT1aR)). These results demonstrate that PCB77 augments AngII-induced atherosclerosis and AAA formation.

Females with Reduced Fertility Have Excess Androstenedione in Follicular Fluid, Altered Theca Gene Expression and Increased VEGFA164b, Maternal Effect, and microRNA Processing mRNA Levels in Cumulus-Oocyte Complexes.

Ovarian dysfunction contributes significantly to female infertility. However, the intrinsic and exogenous factors that result in abnormal ovarian function are poorly defined. Thus, we have established a cow model of fertility to identify mechanisms regulating follicular growth, steroidogenesis and oocyte growth and maturation. Culling age due to failure to establish pregnancy was used to classify animals with low (>/= 2 years-of-age), moderate (> 2 - < 6 years-of-age), and high (>/= 6 years-of-age) fertility. Previous experiments using this model identified class-dependent changes in mural granulosa cell gene expression. The objective of this study was to identify the effect of ovarian and follicular environment on the oocyte molecular phenotype. To attain this objective, females from each fertility group were synchronized using a modified Co-Sync (CIDR) protocol and ovariectomies were performed 36 h after PGF2-alpha injection and CIDR removal. Surface antral follicle counts (AFC) for each ovary pair and the follicular fluid, theca cells, mural granulosa cells and cumulus-oocyte complex (COC) from each dominant follicle were collected. Dominant follicles were confirmed based on size (i.e. largest follicle on the ovaries) and an estrogen- to-progesterone ratio greater than 1.0 in the follicular fluid. Antral follicle counts were lower in low fertility (n = 14) than moderate (n = 17) or high fertility (n = 17) cows. Furthermore, androstenedione (A4) concentrations were 4 fold (P < 0.002) greater in follicular fluid from low compared to high fertility group cows. Given that increased androgens is a hallmark characteristic of the PCOS phenotype, gene expression in theca cells from the different fertility groups was compared. The affect of increased intrafollicular androgen levels on cumulus-oocyte gene expression in the dominant follicle was also examined. Quantitative, real-time RT-PCR demonstrated that mRNA abundance of maternal effect genes NLRP5 (8-fold P < 0.0001), Zar1 (2-fold; P < 0.0001) and Dnmt1 (P < 0.006) and miRNA processing genes DGCR8 (P < 0.005) and RNAsen (P < 0.005) were increased in low compared to high fertility cows. Increased mRNA abundance in low fertility animals is consistent with previous findings in PCOS oocytes and suggests that abnormal endocrine profiles of follicular fluid has a global effect on transcriptional and post-transcriptional regulation of mRNAs in the oocyte. Previous studies identified differences in the expression profile of vascular endothelial growth factor A (VEGFA) isoforms in mural granulosa cells between low, moderate, and high fertility group cows. In the current study, VEGFA_164B mRNA abundance was also increased in cumulus granulosa cells of low fertility cows (P < 0.005). Taken together, these data indicate that females with low fertility have intrinsic differences in ovarian morphology and steroidogenesis. Furthermore, the data suggest that increased androgen production in low fertility animals alters gene expression and/or mRNA stability during oocyte growth and maturation. These changes in oocyte gene expression may reduce the developmental competence of the oocyte and contribute to the reduced pregnancy rates in low fertility cows. USDA is an equal opportunity employer. (poster)

Caveolin-1 modulates TGF-β1 signaling in cardiac remodeling

The cardiac response to myocardial injury includes fibrotic and hypertrophic processes and a key mediator in this response is transforming growth factor-β1 (TGF-β1). Caveolin-1 (cav1), the main structural protein of caveolae, is an inhibitor of the TGF-β1 signaling pathway. To examine the role of cav1 in cardiac repair, cav1 deficient (Cav1−/−) and wild type (WT) mice were subjected to cryoinjury of the left ventricle (LV). At baseline the two groups exhibited no inflammation, similar collagen content, and similar cardiac function. After injury, Cav1−/− animals displayed enhanced TGF-β1 signaling, as reflected by a 3-fold increase in the activation of the Smad2-dependent pathway and more widespread collagen deposition in the heart. Qualitative and quantitative analyses indicated that collagen deposition peaked in the WT LV 14days after injury, accompanied by increased mRNA abundance for procol1a2 (2-fold) and procol3a1 (3-fold). Collagen deposition was further enhanced in Cav1−/− mice, which was accompanied by reduced expression of matrix metalloproteinases MMP-8 (3-fold) and -13 mRNA (2-fold). The levels of expression of inflammatory markers of acute phase were similar between the strains However, macrophage clearance in the damaged region was delayed in Cav1−/− mice. We observed a 4-fold decrease in collagen deposition in Cav1−/− mice injected with a cav1 scaffolding domain peptide (CSD) and a 2-fold decrease in WT mice treated with the CSD. We conclude that cav1 has a direct role in reducing TGF-β1 signaling and as such might be an appropriate target for therapies to influence cardiac remodeling.

Effect of Exercise Training Modality on Skeletal Muscle mRNA Abundance in Young and Older Adults

PURPOSE: The specific effects of different exercise modalities on mitochondrial (mito) and myofibrillar (myo) protein gene expression are not fully understood. We determined the effects of endurance (ET), resistance (RT), and combined (CT) training on skeletal muscle mRNA abundance of mito and myo proteins in young and older adults. METHODS: 33 young (25+1y) and 27 older (70+2y) adults were randomized to one of three 8-wk training interventions: (i) Control: subjects maintained existing physical activity levels, (ii) ET: subjects cycled for 60 min at 65% of VO2 peak, 5×/wk. (iii), RT: subjects RT 4×/wk. Control subjects completed an additional 8-week (iv) CT training program following the completion of the control period. Subjects were assessed for VO2 peak, leg press 1RM, and had muscle biopsies before and 48 h after the last training session. Real-time PCR determined mRNA abundance of mito and myo proteins. ANOVA models were used to detect mean differences. RESULTS: At baseline, there were no significant differences between treatment groups for mRNA abundance. Also, the older subjects had lower VO2 peak (28+1 ml/kg/min vs. 18+1 ml/kg/min, p<0.05) and leg-press 1RM (130+8 kg vs. 80+6 kg, p<0.05). Table 1 presents the pre-posttraining % change values. CONCLUSIONS: ET increased VO2 peak and mRNA abundance of mito proteins in both young and older adults. RT increased skeletal muscle strength in both young and older adults. Although RT did not alter mRNA abundance of mito proteins in the young, these gene transcripts did increase in response to RT among the old. CT increased both VO2 peak and skeletal muscle strength, while also increasing mRNA abundance of mito and myo proteins in both young and older adults. Grants: R01AG09531, KL2RR084151Table 1: Percent change in fitness and mRNA abundance for mitochondrial and contractile proteins.

Cold-inducible expression of AZI1 and its function in improvement of freezing tolerance of Arabidopsis thaliana and Saccharomyces cerevisiae

AZI1 ( AZELAIC ACID INDUCED 1) of Arabidopsis thaliana could be induced by azelaic acid and was involved in priming of systemic plant immunity. In the present work, expression of AZI1 in response to low temperature was investigated via RNA gel blot analysis. AZI1 could be induced slowly by cold stress and more than 6 h treatment at 4 °C was required to detect an increase in mRNA abundance. However, the high expression state could not be maintained stably and would decline to basal level when the plants were transferred to room temperature. In order to clarify the function of AZI1 in resistance to abiotic stresses, overexpressing, RNA interference and T-DNA knockout lines of this gene were used in electrolyte leakage assays. Overexpression of AZI1 resulted in reduced electrolyte leakage during freezing damage. In contrast, AZI1 knockdown and knockout lines showed increased tendencies in cellular damage after freezing treatment. To further validate the potential resistance of AZI1 to low-temperature stress, Saccharomyces cerevisiae cells were transformed with pESC- AZI1 in which AZI1 was under the control of GAL1 promoter. Compared to yeast cells containing empty pESC-URA, the survival rate of yeast cells harboring AZI1 increased obviously after freezing treatment. All these results suggested that AZI1 might be multifunctional and associated with cold tolerance of Arabidopsis.

Effect of exercise training modality on skeletal muscle mitochondrial biogenesis in young and older adults

The specific effects of different exercise modalities on mitochondria (mito) biogenesis are not fully understood. We determined the effects of endurance (ET), resistance (RT), and combined (CT) training on skeletal muscle mito biogenesis in young (Y) and older (O) adults. 33 young (25±1 y) and 27 older adults (70±2 y) were randomized to one of three 8wk interventions: (i) Control: activity levels unchanged, (ii) ET: cycling 60 min at 65% VO2peak, 5x/wk. (iii), RT: RT 4x/wk. After completing the control condition, the controls completed an 8wk (iv) CT program. Percutaneous muscle biopsies were acquired before intervention and 48h following the last training session. rtPCR was used to determine mtDNA and mRNA abundance of genes encoding transcriptional regulators of mito biogenesis (PGC1α, TFAM, NRF1, NRF2, SIRT1, SIRT3) with statistical analysis by ANOVA (mean (SEM)). ET and CT increased mtDNA in the O [63 (26)%, and 86 (35)%, p<0.05], but not Y. ET increased PGC1α [41 (20)%, 23 (14)%], NRF2 [60 (14)%, 22 (14)%], and SIRT3 [24 (9)%, 24 (9)%] mRNA abundance in the Y and O (P<0.05). CT also increased PGC1α [65.5 (26.3)%, 84 (50)%], TFAM [28 (13)%, 32 (23)%], and SIRT3 [24 (6)%, 35 (13)%] mRNA abundance in the Y and O (P<0.05). In conclusion, both ET and CT were effective at increasing mRNA abundance of genes encoding transcriptional regulators of mito biogenesis in both Y and O adults. Funding: R01AG09531, KL2RR084151, UL1RR24150

Cerebral Arteriogenesis is Enhanced by Pharmacological as Well as Fluid-Shear-Stress Activation of the Trpv4 Calcium Channel

Objectives This study aimed to determine the importance of the shear-stress-sensitive calcium channels Trpc1, Trpm7, Trpp2, Trpv2 (transient receptor potential cation channel, subfamily V, member 2) and Trpv4 for cerebral arteriogenesis. The expression profiles were analysed, comparing the stimulation of collateral growth by target-specific drugs to that achieved by maximum increased fluid shear stress (FSS). Design A prospective, controlled study wherein rats were subjected to bilateral carotid artery ligature (BCL), or BCL + arteriovenous fistula, or BCL + drug application. Methods Messenger RNA (mRNA) abundance and protein expression were determined in FSS-stimulated cerebral collaterals by quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry. Drugs were applied via osmotic mini pumps and arteriogenesis was evaluated by post-mortem angiograms and Ki67 immunostaining. Results Trpv4 was the only mechanosensitive Trp channel showing significantly increased mRNA abundance and protein expression after FSS stimulation. Activation of Trpv4 by 4α-phorbol-12,13-didecanoate caused significantly enhanced collateral growth (length: 4.43 ± 0.20 mm and diameter: 282.6 ± 8.1 μm) compared with control (length: 3.80 ± 0.06 mm and diameter: 237.3 ± 5.3 μm). Drug application stimulated arteriogenesis to almost the same extent as did maximum FSS stimulation (length: 4.61 ± 0.07 mm and diameter: 327.4 ± 12.6 μm). Conclusions Trpv4 showed significantly increased expression in FSS-stimulated cerebral collaterals. Pharmacological Trpv4 activation enhanced cerebral arteriogenesis, pinpointing Trpv4 as a possible candidate for the development of new therapeutic concepts.

Decorin GAG Synthesis and TGF-β Signaling Mediate Ox-LDL–Induced Mineralization of Human Vascular Smooth Muscle Cells

Decorin and oxidized low-density lipoprotein (Ox-LDL) independently induce osteogenic differentiation of vascular smooth muscle cells (VSMCs). We aimed to determine whether decorin glycosaminoglycan (GAG) chain synthesis contributes to Ox-LDL-induced differentiation and calcification of human VSMCs in vitro. Human VSMCs treated with Ox-LDL to induce oxidative stress showed increased alkaline phosphatase (ALP) activity, accelerated mineralization, and a difference in both decorin GAG chain biosynthesis and CS/DS structure compared with untreated controls. Ox-LDL increased mRNA abundance of both xylosyltransferase (XT)-I, the key enzyme responsible for GAG chain biosynthesis and Msx2, a marker of osteogenic differentiation. Furthermore, downregulation of XT-I expression using small interfering RNA blocked Ox-LDL-induced VSMC mineralization. Adenoviral-mediated overexpression of decorin, but not a mutated unglycanated form, accelerated mineralization of VSMCs, suggesting GAG chain addition on decorin is crucial for the process of differentiation. The decorin-induced VSMC osteogenic differentiation involved activation of the transforming growth factor (TGF)-β pathway, because it was attenuated by blocking of TGF-β receptor signaling and because decorin overexpression potentiated phosphorylation of the downstream signaling molecule smad2. These studies provide direct evidence that oxidative stress-mediated decorin GAG chain synthesis triggers TGF-β signaling and mineralization of VSMCs in vitro.

130 THE SYNERGIC EFFECT OF NERVE GROWTH FACTOR AND VASCULAR ENDOTHELIAL GROWTH FACTOR ON IN VITRO MATURATION AND DEVELOPMENTAL COMPETENCE IN BOVINE OOCYTES

Nerve growth factor (NGF) has been reported to increase the mRNA expression of vascular endothelial growth factor (VEGF) in granulose cells of human, rat via TrkA signaling; VEGF has been shown to exert beneficial effects during bovine in vitro maturation (IVM) as well as early embryonic development. The aims of this study were 1) to investigate not only the direct effect of NGF but also the collaborative effect of NGF and VEGF during bovine in vitro maturation (IVM), in vitro culture (IVC), or both; and 2) to validate the correlation among transcript abundance of 7 genes (VEGF164, VEGF120, Flt-1, Flk-1, TrkA, PTGS2, and CYP11A1) in bovine cumulus cells and the results of IVM or IVC among the differently treated groups. In Experiment 1, concentrations of 0, 10, and 100 ng mL–1 NGF were added to our established IVM medium without serum, and in Experiment 2, control and treatment groups (concentration of 0, 10, and 100 ng mL–1 NGF with VEGF 100 ng mL–1) were added into chemically defined media. The oocytes of each group in Experiments 1 and 2 were determined by the proportion of MII oocytes after 24 h, and embryos were assessed after parthenogenetic activation. Cumulus cells from the differently treated matured cumulus cell–oocyte complexes (COC) were separated and synthesised into cDNA for RT-PCR and real-time PCR in order to measure relative abundance of 7 genes in a dose-dependent manner or a time-dependent manner. In Experiment 1, the concentration of 10 ng mL–1 (57.40%) and 100 ng mL–1 (62.75%) NGF treatment groups did not significantly increase the proportion of MII oocytes compared with the control group (55.06%). In Experiment 2, both the NGF 10 ng mL–1 with VEGF 100 ng mL–1 treated group (67.69%; P ≤ 0.01) and the NGF 100 ng mL–1 with VEGF 100 ng mL–1 treated group (72.24%; P ≤ 0.001) had a significantly higher percentage of polar body extrusion than control group (51.77%) and the group which was treated with VEGF 100 ng mL–1 (56.39%). The NGF treatment group with VEGF increased transcriptional level of VEGF164 and VEGF120 compared with the control group and only NGF- or VEGF-treated groups. In addition, either the NGF-treated group or NGF plus VEGF showed significantly increased mRNA abundance in VEGF164, VEGF120, Flt-1, Flk-1, and TrkA genes, whereas the NGF plus VEGF-treated group indicated the up-regulation of VEGF164, VEGF120, CYP11A1, and PTGS2 genes. In conclusion, NGF and exogenous VEGF have a synergic effect during bovine IVM and the early stage of embryo development; the elevated VEGF mRNA abundance in cumulus cells might contribute to the viability of bovine oocytes and early embryonic development. This study was supported by grants from IPET (#109023-05-1-CG000), NRF (#M10625030005-10N250300510), MKE (#2009-67-10033839, #2009-67-10033805), and BK21 program.

Regulation of mRNAs encoding the steroidogenic acute regulatory protein and cholesterol side-chain cleavage enzyme in the elasmobranch interrenal gland

The rate-limiting and regulated step in steroidogenesis, the conversion of cholesterol to pregnenolone, is facilitated by the steroidogenic acute regulatory protein (StAR) and cytochrome P450 cholesterol side-chain cleavage (P450scc). We have isolated cDNAs encoding StAR and P450scc from the Atlantic stingray, Dasyatis sabina, and characterized the steroidogenic activity of the encoded proteins using a heterologous expression system. Green monkey kidney (COS-1) cells cotransfected with D. sabina StAR and human P450scc/adrenodoxin reductase/adrenodoxin fusion (F2) constructs produced significantly more pregnenolone than cells transfected with the F2 construct alone. COS-1 cells transfected with a modified F2 construct (F2DS) in which human P450scc is replaced by D. sabina P450scc had higher rates than cells transfected with D. sabina P450scc alone. In other vertebrates, the stress peptide adrenocorticotropic hormone (ACTH) elicits its effects on corticosteroidogenesis in part through regulation of StAR and P450scc mRNAs. In vitro incubation of D. sabina interrenal tissue with porcine ACTH significantly increased intracellular cAMP and corticosteroid production. As demonstrated by quantitative PCR, ACTH also induced significant increases in mRNA abundance of both StAR and P450scc. Our results suggest that, as in higher vertebrates, chronic ACTH-induced glucocorticoid synthesis in elasmobranchs is mediated by regulation of primary steroidogenic mRNAs. This study is the first to demonstrate steroidogenic activity of an elasmobranch P450scc protein and express a composite elasmobranch steroidogenic pathway in a heterologous cell line. Also, the regulation of StAR and P450scc mRNAs has not previously been demonstrated in elasmobranch fishes.

Localization of members of MCT monocarboxylate transporter family Slc16 in the kidney and regulation during metabolic acidosis

The monocarboxylate transporter family (MCT) comprises 14 members with distinct transport properties and tissue distribution. The kidney expresses several members of the MCT family, but only little is known about their exact distribution and function. Here, we investigated selected members of the MCT family in the mouse kidney. MCT1, MCT2, MCT7, and MCT8 localized to basolateral membranes of the epithelial cells lining the nephron. MCT1 and MCT8 were detected in proximal tubule cells whereas MCT7 and MCT2 were located in the thick ascending limb and the distal tubule. CD147, a beta-subunit of MCT1 and MCT4, showed partially overlapping expression with MCT1 and MCT2. However, CD147 was also found in intercalated cells. We also detected SMCT1 and SMCT2, two Na(+)-dependent monocarboxylate cotransporters, on the luminal membrane of type A intercalated cells. Moreover, mice were given an acid load for 2 and 7 days. Acidotic animals showed a marked but transient increase in urinary lactate excretion. During acidosis, a downregulation of MCT1, MCT8, and SMCT2 was observed at the mRNA level, whereas MCT7 and SMCT1 showed increased mRNA abundance. Only MCT7 showed lower protein abundance whereas all other transporters remained unchanged. In summary, we describe for the first time the localization of various MCT transporters in mammalian kidney and demonstrate that metabolic acidosis induces a transient increase in urinary lactate excretion paralleled by lower MCT7 protein expression.

Arabidopsis spermidine synthase is targeted by an effector protein of the cyst nematode Heterodera schachtii.

Cyst nematodes are sedentary plant parasites that cause dramatic cellular changes in the plant root to form feeding cells, so-called syncytia. 10A06 is a cyst nematode secretory protein that is most likely secreted as an effector into the developing syncytia during early plant parasitism. A homolog of the uncharacterized soybean cyst nematode (Heterodera glycines), 10A06 gene was cloned from the sugar beet cyst nematode (Heterodera schachtii), which is able to infect Arabidopsis (Arabidopsis thaliana). Constitutive expression of 10A06 in Arabidopsis affected plant morphology and increased susceptibility to H. schachtii as well as to other plant pathogens. Using yeast two-hybrid assays, we identified Spermidine Synthase2 (SPDS2), a key enzyme involved in polyamine biosynthesis, as a specific 10A06 interactor. In support of this protein-protein interaction, transgenic plants expressing 10A06 exhibited elevated SPDS2 mRNA abundance, significantly higher spermidine content, and increased polyamine oxidase (PAO) activity. Furthermore, the SPDS2 promoter was strongly activated in the nematode-induced syncytia, and transgenic plants overexpressing SPDS2 showed enhanced plant susceptibility to H. schachtii. In addition, in planta expression of 10A06 or SPDS2 increased mRNA abundance of a set of antioxidant genes upon nematode infection. These data lend strong support to a model in which the cyst nematode effector 10A06 exerts its function through the interaction with SPDS2, thereby increasing spermidine content and subsequently PAO activity. Increasing PAO activity results in stimulating the induction of the cellular antioxidant machinery in syncytia. Furthermore, we observed an apparent disruption of salicylic acid defense signaling as a function of 10A06. Most likely, increased antioxidant protection and interruption of salicylic acid signaling are key aspects of 10A06 function in addition to other physiological and morphological changes caused by altered polyamines, which are potent plant signaling molecules.

Maternal parity and its effect on adipose tissue deposition and endocrine sensitivity in the postnatal sheep

Maternal parity influences size at birth, postnatal growth and body composition with firstborn infants being more likely to be smaller with increased fat mass, suggesting that adiposity is set in early life. The precise effect of parity on fat mass and its endocrine sensitivity remains unclear and was, therefore, investigated in the present study. We utilised an established sheep model in which perirenal–abdominal fat mass (the major fat depot in the neonatal sheep) increases ∼10-fold over the first month of life and focussed on the impact of parity on glucocorticoid sensitivity and adipokine expression in the adipocyte. Twin-bearing sheep of similar body weight and adiposity that consumed identical diets were utilised, and maternal blood samples were taken at 130 days of gestation. One offspring from each twin pair was sampled at 1 day of age, coincident with the time of maximal recruitment of uncoupling protein 1 (UCP1), whilst its sibling was sampled at 1 month, when UCP1 had disappeared. Plasma leptin was lower in nulliparous mothers than in multiparous mothers, and offspring of nulliparous mothers possessed more adipose tissue with increased mRNA abundance of leptin, glucocorticoid receptor and UCP2, adaptations that persisted up to 1 month of age when gene expression for interleukin-6 and adiponectin was also raised. The increase in fat mass associated with firstborn status is therefore accompanied by a resetting of the leptin and glucocorticoid axis within the adipocyte. Our findings emphasise the importance of parity in determining adipose tissue development and that firstborn offspring have an increased capacity for adipogenesis which may be critical in determining later adiposity.