Hyperglycemia modulates angiotensinogen gene expression

Elevated plasma angiotensinogen (AGT) levels have been demonstrated in insulin-resistant states such as obesity and type 2 diabetes mellitus (DM2), conditions that are directly correlated to hypertension. We examined whether hyperinsulinemia or hyperglycemia may modulate fat and liver AGT gene expression and whether obesity and insulin resistance are associated with abnormal AGT regulation. In addition, because the hexosamine biosynthetic pathway is considered to function as a biochemical sensor of intracellular nutrient availability, we hypothesized that activation of this pathway would acutely mediate in vivo the induction of AGT gene expression in fat and liver. We studied chronically catheterized lean (∼300 g) and obese (∼450 g) Sprague-Dawley rats in four clamp studies ( n= 3/group), creating physiological hyperinsulinemia (∼60 μU/ml, by an insulin clamp), hyperglycemia (∼18 mM, by a pancreatic clamp using somatostatin to prevent endogenous insulin secretion), or euglycemia with glucosamine infusion (GlcN; 30 μmol · kg−1 · min−1) and equivalent saline infusions (as a control). Although insulin infusion suppressed AGT gene expression in fat and liver of lean rats, the obese rats demonstrated resistance to this effect of insulin. In contrast, hyperglycemia at basal insulin levels activated AGT gene expression in fat and liver by approximately threefold in both lean and obese rats ( P < 0.001). Finally, GlcN infusion simulated the effects of hyperglycemia on fat and liver AGT gene expression (2-fold increase, P < 0.001). Our results support the hypothesis that physiological nutrient “pulses” may acutely induce AGT gene expression in both adipose tissue and liver through the activation of the hexosamine biosynthetic pathway. Resistance to the suppressive effect of insulin on AGT expression in obese rats may potentiate the effect of nutrients on AGT gene expression. We propose that increased AGT gene expression and possibly its production may provide another link between obesity/insulin resistance and hypertension.

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Abstract 41: Explant-Derived Cells from Chronic Heart Failure Activated Endothelial-Mesenchymal Transition and Attenuated Pluripotency Genes Expression

Circulation Research ◽

10.1161/res.111.suppl_1.a41 ◽

2012 ◽

Vol 111 (suppl_1) ◽

Author(s):

Liudmila Zakharova ◽

Hikmet Nural ◽

Mohamed A Gaballa

Keyword(s):

Gene Expression ◽

Progenitor Cells ◽

Smooth Muscle Actin ◽

Fold Increase ◽

Gene Expressions ◽

Mesenchymal Transition ◽

Cell Outgrowth ◽

Pluripotency Genes

Cardiac progenitor cells are generated from atria explants; however the cellular origin and the mechanisms of cell outgrowth are unclear. Using transgenic tamoxifen-induced Willms tumor 1 (Wt1)-Cre/ERT and Cre-activated GFP reporter mice, we found approximately 40% of explant-derived cells and 74% of explant-derived c-Kit+ cells originated from the epicardium. In atria from sham hearts, Wt1+ cells were located in a thin epicardial layer, while c-Kit+ cells were primarily found within both the sub-epicardium and the myocardium, albeit at low frequency. No overlap between c-Kit+ and Wt1+ cells was observed, suggesting that epicardial Wt1+ cells do not express c-Kit marker in vivo, but more likely the c-Kit marker was acquired in culture. Compared with 4 days in culture, at day 21 we observed 7 folds increase in Snail gene expression; 32% increase in α-smooth muscle actin (SMA) marker, and 30% decrease in E-cadherin marker, suggesting that the explant-derived cells underwent epithelial to mesenchymal transition (EMT) in vitro. Cell outgrowths released TGF-β (1036.4 ± 1.18 pm/ml) and exhibited active TGF-β signaling, which might triggered the EMT. Compared to shams, CHF cell outgrowths exhibited elevated levels of EMT markers, SMA (49% vs. 34%) and Snail (2 folds), and reduced level of Wt1 (11% vs. 22%). In addition, CHF cell outgrowths had two folds increase in Pai1 gene expression, a direct target of TGF-β signaling. In c-Kit+ cells derived from CHF explants, Nanog gene expression was 4 folds lower and Sox 2 was 2 folds lower compared with cells from shams. Suppression of EMT in cell outgrowth increased the percentage of c-Kit+ and Wt1+ cells by 17%, and 15%, respectively. Also suppression of EMT in c-Kit+ cells resulted in 4 folds increase in Nanog and 3 fold increase in Sox2 gene expressions. Our results showed that CHF may further exuberates EMT while diminishes the re-activation of pluripotency genes. Thus, EMT modulation in CHF is a possible strategy to regulate both the yield and the pluripotency of cardiac-explant-derived progenitor cells.

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Hyperglycemia induces PAI-1 gene expression in adipose tissue by activation of the hexosamine biosynthetic pathway

Atherosclerosis ◽

10.1016/s0021-9150(01)00574-3 ◽

2002 ◽

Vol 160 (1) ◽

pp. 115-122 ◽

Cited By ~ 41

Author(s):

Ilan Gabriely ◽

Xiao Man Yang ◽

Jane A Cases ◽

Xiao Hui Ma ◽

Luciano Rossetti ◽

...

Keyword(s):

Gene Expression ◽

Adipose Tissue ◽

Biosynthetic Pathway ◽

Hexosamine Biosynthetic Pathway ◽

Pai 1

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Regulation of mdrlb gene expression in Fischer, Wistar and Sprague-Dawley rats in vivo and in vitro

Carcinogenesis ◽

10.1093/carcin/17.3.451 ◽

1996 ◽

Vol 17 (3) ◽

pp. 451-457 ◽

Cited By ~ 19

Author(s):

Barbara A. Hill ◽

Paul C. Brown ◽

Karl-Heinz Preisegger ◽

Jeffrey A. Silverman

Keyword(s):

Gene Expression ◽

Sprague Dawley ◽

Sprague Dawley Rats

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Abstract P636: Insulin Resistance in Obesity Results in Postprandial Salt and Water Loss

Hypertension ◽

10.1161/hyp.68.suppl_1.p636 ◽

2016 ◽

Vol 68 (suppl_1) ◽

Author(s):

Debra L Irsik ◽

Ashley R Washington ◽

Rabei Alaisami ◽

Michael W Brands

Keyword(s):

Insulin Resistance ◽

Blood Glucose ◽

Water Loss ◽

Urine Volume ◽

Zucker Rats ◽

Sprague Dawley ◽

Insulin Resistant ◽

Dual Channel ◽

Obese Rats ◽

Postprandial Insulin

Obesity and insulin resistance contribute to the development of metabolic syndrome, a growing epidemic in our country. The obese Zucker rat is an experimental model of this disease. Previously, using Sprague Dawley rats, we have shown that the normal postprandial rise in insulin acts physiologically to prevent renal salt and water wasting after meals. This study tested whether the effects of postprandial insulin would be attenuated in insulin resistant rats and result in excess salt and water loss. Chronic artery and vein catheters were implanted in male lean and obese Zucker rats for infusion and blood sampling. Rats were housed in metabolic cages and their catheters were connected to dual-channel Instech swivels for access. Over a 24-hr period of ad libitum eating, blood glucose was not different between obese and lean rats (127±7 vs. 120±3 mg/dl) but obese rats were hyperinsulinemic (14.86 vs. 0.98 ng/ml). Obese rats had significantly greater urine volume than lean controls (22.5±1.2 vs. 14.7±0.9 ml) despite similar water intakes. Obese rats tended to excrete more Na+ than lean controls (3.46±0.15 vs. 2.97±0.35 mEq) with equal amounts of Na+ intake. To evaluate the response to a single meal while controlling for blood glucose, fasted rats were administered a glucose bolus (as 50% dextrose) that yielded peak levels of blood glucose that were not different in the two groups (589±11 vs. 596 ±3 mg/dl at t=5 min.). Plasma insulin increased from fasting in both groups to 26.35 and 9.34 ng/ml in obese and lean controls, respectively. Over the 4-hour period following the glucose administration, obese rats had significantly greater urine volume (8.6±1.3 vs. 2.2 ±0.6 ml) and Na+ excretion (0.53±0.11 vs. 0.25±0.09 mEq) than lean controls. This suggests that insulin resistance of obesity may impair the ability of postprandial insulin to participate in maintenance of Na+ and water homeostasis, but the potential role of insulin resistance specifically within the kidney requires further study.

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3 IN VITRO MATURATION ALTERS GENE EXPRESSION IN MOUSE OOCYTES

Reproduction Fertility and Development ◽

10.1071/rdv20n1ab3 ◽

2008 ◽

Vol 20 (1) ◽

pp. 82

Author(s):

M. Paczkowski ◽

C. Bidwell ◽

D. Spurlock ◽

J. Waddell ◽

R. L. Krisher

Keyword(s):

Gene Expression ◽

Cell Death ◽

Dna Methyltransferase ◽

In Vitro Maturation ◽

Fold Increase ◽

Developmental Competence ◽

Differentially Expressed ◽

Dna Methyltransferase 1

The in vitro culture environment significantly impacts nuclear maturation, fertilization, embryonic development, and epigenetic competence; however, our knowledge of the effects of in vitro maturation on oocyte developmental competence, and specifically cytoplasmic maturation, is limited. The objective of this experiment was to identify alterations in the transcriptome of oocytes matured in vitro compared to those matured in vivo that correlate to developmental competence. Immature oocytes were collected from Day 26 and 7-8-week-old B6D2F1 mice 48 h post-pregnant mare serum gonadotropin (PMSG) administration and matured for 16 h in Gmat supplemented with 0.5 mm citric acid, 0.5 mm cysteamine, 100 ng mL–1 epidermal growth factor (EGF), 0.05% insulin-transferrin-selenium (ITS; v/v), 0.01% recombumin (v/v) and 2 mg mL–1 fetuin. In vivo-matured oocytes from females of the same ages were collected from the oviducts 62 h post-PMSG and 14 h post-hCG and mating to vasectomized males. In vivo- and in vitro-matured oocytes were identified visually by the presence of the first polar body. Mature oocytes were pooled into three groups of 150 oocytes per treatment and lysed; poly A+ RNA was extracted. Samples were processed through two cycles of linear amplification and hybridized to the GeneChip� Mouse Genome 430 2.0 Array (Affymetrix, Inc., Santa Clara, CA, USA), with three arrays per treatment. Microarray data were sorted and filtered to include genes that were classified as having two present calls per treatment. The data were then normalized to the chip median and analyzed using a one-way analysis of variance; the level of significance was calculated at P < 0.01. In total, 2.17% (482/22170) and 1.61% (358/22170) of genes were differentially expressed between in vitro- and in vivo-matured oocytes in Day 26 and 7–8-week-old mice, respectively. However, 72.82% (351/482) and 67.87% (243/358) of differentially expressed genes had increased abundance in the in vitro- and in vivo-matured oocytes, respectively. Transcripts involved in gene expression, cellular growth and proliferation, and cellular development were increased in in vivo-matured oocytes from both age groups compared to those matured in vitro. Cell death was one of the higher ranking functional groups increased in the 7–8-week-old in vitro-matured oocytes compared to the 7–8-week-old in vivo-matured oocytes. Specific genes altered by in vitro maturation conditions in Day 26 oocytes were DNA methyltransferase 1 (>7-fold increase in vivo), caspase 8 (>4-fold increase in vivo), and eukaryotic translation initiation factor 1B (>4-fold increase in vivo). DNA methyltransferase 1 and ubiquitin-conjugating enzyme E2T were significantly increased in in vivo-matured 7–8-week-old oocytes (>3-fold and >5-fold, respectively). These results indicate that gene expression is altered in oocytes matured in vitro compared to those matured in vivo. Based on the functional annotations of genes differentially expressed, dysregulation of gene expression in the oocyte resulting in altered DNA methylation and an up-regulation in cell death pathways are potential developmental mechanisms influenced by in vitro culture conditions that correlate to reduced embryonic developmental potential.

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Acute hypoxia stimulates renin secretion and renin gene expression in vivo but not in vitro

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1997.272.4.r1105 ◽

1997 ◽

Vol 272 (4) ◽

pp. R1105-R1111 ◽

Cited By ~ 4

Author(s):

T. Ritthaler ◽

K. Schricker ◽

F. Kees ◽

B. Kramer ◽

A. Kurtz

Keyword(s):

Gene Expression ◽

Acute Hypoxia ◽

Primary Cultures ◽

Renin Secretion ◽

Plasma Norepinephrine ◽

Mrna Levels ◽

Sprague Dawley ◽

Renin Gene ◽

Renin Mrna

This study aimed at examining the influence of acute hypoxia on renin secretion and renin gene expression in the kidney. To this end, male Sprague-Dawley rats were exposed to severe hypoxic stress (8% O2) or to carbon monoxide (0.1% CO) for 6 h, and plasma renin activity (PRA) and renal renin mRNA levels were determined. PRA values increased from 3 to 13 and 10 ng angiotensin I x h(-1) x ml(-1), and renin mRNA levels increased by 120 and 100% during hypoxia and CO, respectively. Lowering the PO2 from 150 to 20 or 7 mmHg in the gas atmosphere of primary cultures of renal juxtaglomerular cells had no influence on renin secretion and renin gene expression after 6 and 20 h. Our findings thus suggest that both arterial and venous hypoxia can be powerful stimulators of renin secretion and renin gene expression in vivo. Because renal denervation did not prevent stimulation of the renin system by hypoxia, the effect could be indirectly mediated via the baroreceptor-macula densa mechanism. Another potential mediator of the effect could be circulating catecholamines, since we found that plasma norepinephrine increased from 0.7 to 1.5 and 2.4 ng/ml and plasma epinephrine increased from 0.3 to 1.4 and 2.7 ng/ml during hypoxia and CO inhalation, respectively.

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IL-2 Therapy Promotes the Expansion of Human CD4+CD25+ Regulatory T Cells and Selectively Upregulates the Expression of FOXP3 in T Cells In Vivo.

Blood ◽

10.1182/blood.v106.11.1257.1257 ◽

2005 ◽

Vol 106 (11) ◽

pp. 1257-1257

Author(s):

Emmanuel Zorn ◽

Erik A. Nelson ◽

Mehrdad Mohseni ◽

Despina Litsa ◽

Haesook Kim ◽

...

Keyword(s):

Gene Expression ◽

T Cells ◽

Regulatory T Cells ◽

Nk Cells ◽

Quantitative Pcr ◽

Peripheral Blood ◽

Fold Increase ◽

Foxp3 Expression ◽

Prolonged Administration

Abstract Recombinant IL-2 has been used extensively in clinical trials to enhance a wide range of immune responses. Overall this strategy has had limited efficacy. Recent evidence suggests that IL-2 plays a key role in the generation and maintenance of CD4+CD25+ regulatory T cells (Treg) in vivo. In our study, we investigated the effect of prolonged administration of recombinant IL-2 on Treg in vivo. In a retrospective analysis, we first examined CD4+CD25+ Treg in blood samples collected from 21 cancer patients before and after they started continuous treatment with IL-2 at a dose of 2 X 105 U/m2/day for 3 months. Nine patients received IL-2 beginning 3 months after CD6 T cell depleted allogeneic bone marrow transplantation (BMT) for CML. The remaining 12 patients received IL-2 as treatment for advanced solid tumors. Overall toxicity was minimal and none of the transplant patients developed GVHD following IL-2 administration. Previous reports demonstrated that this prolonged treatment with low-dose IL-2 resulted in the expansion of CD56+CD3− NK cells in peripheral blood. Further analysis showed that 15 patients exhibited an expansion of Treg in peripheral blood 26 to 77 days after beginning IL-2 as demonstrated by an increase in the CD4+CD25+/CD3+ ratio (median fold increase 2.68; range 1.3 to 59). Three patients had no significant change and 3 patients demonstrated a decreased Treg/CD3 ratio. Using RNA from the same samples we also measured the expression of the Treg specific transcription factor FOXP3 by quantitative PCR. Nineteen of 21 patients showed a marked increase in FOXP3 expression following IL-2 treatment (8.38 median fold increase; range 1.4 to 41.5). Only 2 of 21 patients had lower FOXP3 expression after IL-2 administration. Since IL-2 treatment resulted in the expansion of NK cells as well as Treg, we purified CD56+CD3− NK cells and CD4+ T cells from patient samples collected post-IL-2 treatment, and measured FOXP3 gene expression in both subsets. In 4 analyzed cases, FOXP3 was selectively expressed in CD4+ T cells. Further analysis of purified Treg and NK cells incubated with IL-2 in vitro confirmed that FOXP3 expression was selectively induced in Treg, and also suggested that the in vivo increase in FOXP3 expression resulted from both Treg expansion and up-regulation of gene expression at the single cell level. To study the duration of the IL-2 effect, we analyzed additional samples collected 2 to 8 months after IL-2 treatment was completed. Nine of 10 patient samples tested showed a decrease in the CD4+CD25+/CD3+ ratio (1.39 median fold decrease; range 1.13 to 15.02). Using quantitative PCR, expression of FOXP3 decreased for 6 of 8 patients tested (10.76 median fold decrease; range 1.22 to 88.31). These results indicate that prolonged administration of IL-2 promotes the expansion of CD4+CD25+ Treg in vivo and also has a direct effect on FOXP3 expression. Although administration of IL-2 has previously been used to enhance T and NK cell responses, this study demonstrates that IL-2 therapy predominantly reinforces the regulatory component of the immune response, and may provide a means for controlling immune reactions in vivo.

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Modulation of in vivo 3-deoxyglucosone levels

Biochemical Society Transactions ◽

10.1042/bst0311433 ◽

2003 ◽

Vol 31 (6) ◽

pp. 1433-1437 ◽

Cited By ~ 12

Author(s):

T.R. Brown ◽

B. Su ◽

K.A. Brown ◽

M.A. Schwartz ◽

A.M. Tobia ◽

...

Keyword(s):

Fold Increase ◽

Rat Plasma ◽

Diabetic Rat ◽

Kidney Tubules ◽

Sprague Dawley ◽

Birth Rates ◽

Fischer 344 ◽

Sprague Dawley Rats ◽

Eker Rat

Fructoselysine 3-phosphate is synthesized in vivo by the recently discovered fructoseamine-3-kinase (F3K) from fructoselysine and ATP and decomposes to lysine, Pi and 3-deoxyglucosone (3DG). This pathway appears to dominate 3DG production in vivo, making it possible to modulate 3DG levels by stimulating or inhibiting the reaction. Present inhibitors are non-reacting substrate analogues with relatively high Ki values and can inhibit F3K sufficiently in vivo to reduce 3DG in diabetic rat plasma by approx. 50%. Stimulation of the F3K pathway by feeding glycated casein causes an increase of 10–20-fold in plasma levels of 3DG and 3-fold in kidney tubules. Consequences of this increase were studied in two systems: the Eker rat, a model of susceptible kidney tubules; and birth rates in two rat strains. In both cases substantial pathological effects were observed. In the Eker rats, an approx. 3-fold increase in kidney lesions was observed (P<0.00001). In both Fischer 344 and Sprague–Dawley rats, birth rates were reduced by 56% (P<0.0001) and 12% (P<0.015) respectively. These results suggest that inhibition of F3K is a promising new therapeutic target for diabetic complications, as well as other 3DG-dependent pathologies.

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Regulated Hyaluronan Synthesis by Vascular Cells

International Journal of Cell Biology ◽

10.1155/2015/208303 ◽

2015 ◽

Vol 2015 ◽

pp. 1-8 ◽

Cited By ~ 12

Author(s):

Manuela Viola ◽

Evgenia Karousou ◽

Maria Luisa D’Angelo ◽

Ilaria Caon ◽

Giancarlo De Luca ◽

...

Keyword(s):

Gene Expression ◽

Biosynthetic Pathway ◽

Critical Role ◽

Vascular Cells ◽

Substrate Availability ◽

Critical Aspect ◽

Hexosamine Biosynthetic Pathway ◽

Covalent Modifications ◽

Ha Synthase ◽

Synthesis Regulation

Cellular microenvironment plays a critical role in several pathologies including atherosclerosis. Hyaluronan (HA) content often reflects the progression of this disease in promoting vessel thickening and cell migration. HA synthesis is regulated by several factors, including the phosphorylation of HA synthase 2 (HAS2) and other covalent modifications including ubiquitination and O-GlcNAcylation. Substrate availability is important in HA synthesis control. Specific drugs reducing the UDP precursors are able to reduce HA synthesis whereas the hexosamine biosynthetic pathway (HBP) increases the concentration of HA precursor UDP-N-acetylglucosamine (UDP-GlcNAc) leading to an increase of HA synthesis. The flux through the HBP in the regulation of HA biosynthesis in human aortic vascular smooth muscle cells (VSMCs) was reported as a critical aspect. In fact, inhibiting O-GlcNAcylation reduced HA production whereas increased O-GlcNAcylation augmented HA secretion. Additionally, O-GlcNAcylation regulates HAS2 gene expression resulting in accumulation of its mRNA after induction of O-GlcNAcylation with glucosamine treatments. The oxidized LDLs, the most common molecules related to atherosclerosis outcome and progression, are also able to induce a strong HA synthesis when they are in contact with vascular cells. In this review, we present recent described mechanisms involved in HA synthesis regulation and their role in atherosclerosis outcome and development.

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