Effects of moderate global maternal nutrient reduction on fetal baboon renal mitochondrial gene expression at 0.9 gestation

Early life malnutrition results in structural alterations in the kidney, predisposing offspring to later life renal dysfunction. Kidneys of adults who were growth restricted at birth have substantial variations in nephron endowment. Animal models have indicated renal structural and functional consequences in offspring exposed to suboptimal intrauterine nutrition. Mitochondrial bioenergetics play a key role in renal energy metabolism, growth, and function. We hypothesized that moderate maternal nutrient reduction (MNR) would adversely impact fetal renal mitochondrial expression in a well-established nonhuman primate model that produces intrauterine growth reduction at term. Female baboons were fed normal chow diet or 70% of control diet (MNR). Fetal kidneys were harvested at cesarean section at 0.9 gestation (165 days gestation). Human Mitochondrial Energy Metabolism and Human Mitochondria Pathway PCR Arrays were used to analyze mitochondrially relevant mRNA expression. In situ protein content was detected by immunohistochemistry. Despite the smaller overall size, the fetal kidney weight-to-body weight ratio was not affected. We demonstrated fetal sex-specific differential mRNA expression encoding mitochondrial metabolite transport and dynamics proteins. MNR-related differential gene expression was more evident in female fetuses, with 16 transcripts significantly altered, including 14 downregulated and 2 upregulated transcripts. MNR impacted 10 transcripts in male fetuses, with 7 downregulated and 3 upregulated transcripts. The alteration in mRNA levels was accompanied by a decrease in mitochondrial protein cytochrome c oxidase subunit VIc. In conclusion, transcripts encoding fetal renal mitochondrial energy metabolism proteins are nutrition sensitive in a sex-dependent manner. We speculate that these differences lead to decreased mitochondrial fitness that contributes to renal dysfunction in later life.

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Stanniocalcin 2 is positively and negatively controlled by 1,25(OH)2D3 and PTH in renal proximal tubular cells

Journal of Molecular Endocrinology ◽

10.1677/jme-08-0161 ◽

2009 ◽

Vol 42 (3) ◽

pp. 261-268 ◽

Cited By ~ 9

Author(s):

Yuichiro Takei ◽

Hironori Yamamoto ◽

Masashi Masuda ◽

Tadatoshi Sato ◽

Yutaka Taketani ◽

...

Keyword(s):

Gene Expression ◽

Mrna Expression ◽

Mrna Levels ◽

Dependent Manner ◽

Proximal Tubular Cells ◽

Tubular Cells ◽

Ok Cells ◽

Proximal Tubular ◽

Renal Proximal Tubular Cells ◽

Renal Proximal Tubular

We have previously identified a second mammalian stanniocalcin (STC2) in humans and demonstrated that STC2 inhibits phosphate uptake in an opossum renal proximal tubular cell line (opossum kidney (OK) cells). However, the regulation of Stc2 gene expression in OK cells is not well understood. In this study, we identified the opossum Stc2 cDNA sequence. The opossum STC2 amino acid sequence had 78.8% homology with human STC2, and has a conserved putative N-linked glycosylation site. Next, we investigated the regulation of Stc2 gene expression by the classical calcium and phosphate-regulating factors 1,25(OH)2D3 and PTH in OK cells. In western blot analysis using affinity-purified anti-STC2 antibody, the secretion of STC2 protein was stimulated by 1,25(OH)2D3 in a dose-dependent manner. By contrast, PTH suppressed the induction of STC2 protein secretion by 1,25(OH)2D3. Real-time PCR analysis revealed that Stc2 mRNA expression was increased by 1,25(OH)2D3 in a dose- and time-dependent manner. In addition, actinomycin D, an RNA synthesis inhibitor, prevented the effects of 1,25(OH)2D3 on Stc2 gene expression. On the other hand, PTH and phorbol 12,13-myristic acetate, a specific PKC activator, but not 8-bromo-cyclic AMP, a specific PKA activator, reduced the mRNA levels of Stc2. In addition, Gö6976, a specific PKC inhibitor, abolished the downregulation of Stc2 mRNA expression by PTH. Furthermore, we demonstrated that the renal Stc2 mRNA expression was increased by 1,25(OH)2D3 and decreased by PTH in vivo. These results suggest that STC2 is positively and negatively controlled by 1,25(OH)2D3 and PTH in renal proximal tubular cells.

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Corticotropin-Releasing Factor Inhibits Luteinizing Hormone-Stimulated P450c17 Gene Expression and Androgen Production by Isolated Thecal Cells of Human Ovarian Follicles1

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/jcem.83.2.4546 ◽

1998 ◽

Vol 83 (2) ◽

pp. 448-452

Author(s):

H. F. Erden ◽

I. H. Zwain ◽

H. Asakura ◽

S. S. C. Yen

Keyword(s):

Gene Expression ◽

Granulosa Cells ◽

Inhibitory Effect ◽

Corticotropin Releasing Factor ◽

Mrna Levels ◽

Dependent Manner ◽

Messenger Ribonucleic Acid ◽

Estrogen Production ◽

Thecal Cells ◽

Crf System

Recently, we reported that the thecal compartment of the human ovary contains a CRF system replete with gene expression and protein for corticotropin-releasing factor (CRF), CRF-Receptor 1 (CRF-R1), and the blood-derived high affinity CRF-binding protein (CRF-BP). Granulosa cells are devoid of the CRF system. The parallel increases in intensity of CRF, CRF-R1, and 17α-hydroxylase messenger ribonucleic acid (mRNA) and proteins in thecal cells with follicular maturation suggest that the intraovarian CRF system may play an autocrine role regulating androgen biosynthesis, with a downstream effect on estrogen production by granulosa cells. The functionality of the ovarian CRF system may be conditioned by the relative presence of plasma-derived CRF-BP by virtue of its localization of protein, but not transcript in thecal cells and its ability to compete with CRF for the CRF receptor. To further these findings, in the present study we have examined the effect of CRF on LH-stimulated 17α-hydroxylase (P450c17) gene expression and androgen production by isolated thecal cells from human ovarian follicles (11–13 mm). During the 48-h culture, addition of LH (10 ng/mL) to the medium increased by 5- and 6-fold dehydroepiandrosterone and androstenedione production by thecal cells. Remarkably, the LH-stimulated, but not basal, androgen production was inhibited by CRF in a time- and dose-dependent manner. The half-maximal (ID50) effect dose of CRF occurred at 5 × 10−8 mol/L, and at a maximal concentration of 10−6 mol/L, CRF completely inhibited LH-stimulated androgen production. This inhibitory effect of CRF became evident at 12 h (45%), and by 24 h the effect was more pronounced, with a 70% reduction from baseline. As determined by Northern analyses, CRF dose dependently decreased LH-stimulated P450c17 mRNA levels, with a maximal inhibition of 85% P450c17 gene expression at a CRF concentration of 10−6 mol/L. With the addition of 10−6 mol/L of the antagonist α-helical CRF-(9–41), the inhibitory effect of CRF was partially reversed for both P450c17 mRNA (75%) and androgen production (50%), indicating the CRF-R1-mediated event. In conclusion, the present study demonstrated a potent inhibitory effect of CRF on LH-stimulated dehydroepiandrosterone and androstenedione production that appears to be mediated through the reduction of P450c17 gene expression. Thus, the ovarian CRF system may function as autocrine regulators for androgen biosynthesis in the thecal cell compartment to maintain optimal substrate for estrogen biosynthesis by granulosa cells. Further studies to define the role of CRF-BP in the endocrine modulation of the intraovarian CRF system are needed.

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DDR1 methylation is associated with bipolar disorder and the isoform expression and methylation of myelin genes

Epigenomics ◽

10.2217/epi-2021-0006 ◽

2021 ◽

Author(s):

Beatriz Garcia-Ruiz ◽

Manuel Castro de Moura ◽

Gerard Muntané ◽

Lourdes Martorell ◽

Elena Bosch ◽

...

Keyword(s):

Gene Expression ◽

Dna Methylation ◽

Bipolar Disorder ◽

Mrna Expression ◽

Gene Expression Analysis ◽

Mrna Levels ◽

Healthy Controls ◽

Genome Wide ◽

Isoform Expression

Aim: To investigate DDR1 methylation in the brains of bipolar disorder (BD) patients and its association with DDR1 mRNA levels and comethylation with myelin genes. Materials & methods: Genome-wide profiling of DNA methylation (Infinium MethylationEPIC BeadChip) corrected for glial composition and DDR1 gene expression analysis in the occipital cortices of individuals with BD (n = 15) and healthy controls (n = 15) were conducted. Results: DDR1 5-methylcytosine levels were increased and directly associated with DDR1b mRNA expression in the brains of BD patients. We also observed that DDR1 was comethylated with a group of myelin genes. Conclusion: DDR1 is hypermethylated in BD brain tissue and is associated with isoform expression. Additionally, DDR1 comethylation with myelin genes supports the role of this receptor in myelination.

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Abstract 2423: B-type Natriuretic Peptide Upregulates Erythropoietin Receptor Gene Expression via Protein Kinase G in Heart Failure

Circulation ◽

10.1161/circ.118.suppl_18.s_724 ◽

2008 ◽

Vol 118 (suppl_18) ◽

Author(s):

Yoshiaki Ohyama ◽

Toru Tanaka ◽

Takehisa Shimizu ◽

Hiroshi Doi ◽

Norimichi Koitabashi ◽

...

Keyword(s):

Gene Expression ◽

Heart Failure ◽

Protein Kinase ◽

Cardiac Myocytes ◽

Natriuretic Peptide ◽

Neonatal Rat ◽

Mrna Levels ◽

Dependent Manner ◽

Failing Heart ◽

Epor Expression

Backgroud: Recent studies demonstrated non-hematopoietical effects of Erythropoietin (Epo) and its receptor (EpoR) in a variety of tissues including cardiovascular system. Epo treatment improves cardiac function in patients with heart failure and reduces infarct size after ischemia/reperfusion injury in the heart. However, little attention has been paid for the endogenous regulatory mechanisms regulating EpoR expression. In this study, we hypothesize that B-type natriuretic peptide upregulates EpoR gene expression in failing heart. Methods and Results: Wister rats underwent transverse aortic constriction surgery to induce hypertrophy. RT-PCR analyses of those rats showed that EpoR mRNA levels were increased in the left ventricle and positively correlated with the levels of BNP mRNA (n=10, r=0.67, p<0.05). Next we examined the expression of EpoR in human failing heart by using autopsy specimens and found that EpoR mRNA levels were significantly elevated in patients with dilated cardiomyopathy compared with those in normal heart. Immunohistochemistry of endomyocardial biopsy specimens of failing heart (n=54) showed that EpoR mRNA levels were correlated with severity of cardiac dysfunction estimated by diameter of cardiac chambers, pathomorphology, serum BNP concentration and functional class of New York Heart Association. Interestingly, stimulation of cultured neonatal rat cardiac myocytes with BNP, but not with hypertrophic reagents including endothelin I, angiotensin II and norepinephrine, significantly increased the EpoR mRNA levels in a time-dependent manner. Overexpression of cGMP-dependent protein kinase (PKG) increased EpoR transcript in cultured cardiac myocytes. BNP-induced EpoR expression was abrogated in the presence of KT5823, a specific inhibitor for PKG. Conclusion: These results suggest a role for BNP in mediating an induction of EpoR expression in failing myocardium and indicate that the cardiac EpoR gene is a target of cGMP/PKG signaling.

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Interferon-gamma downregulates CFTR gene expression in epithelial cells

AJP Cell Physiology ◽

10.1152/ajpcell.1994.267.5.c1398 ◽

1994 ◽

Vol 267 (5) ◽

pp. C1398-C1404 ◽

Cited By ~ 75

Author(s):

F. Besancon ◽

G. Przewlocki ◽

I. Baro ◽

A. S. Hongre ◽

D. Escande ◽

...

Keyword(s):

Gene Expression ◽

Interferon Gamma ◽

Posttranscriptional Regulation ◽

Bacterial Infections ◽

Cftr Gene ◽

Mrna Levels ◽

Dependent Manner ◽

Necrosis Factor Alpha ◽

Ifn Gamma ◽

Cl Transport

Cystic fibrosis (CF) is caused by mutations in the CF transmembrane conductance regulator (CFTR) gene, resulting in defective transepithelial Cl- transport. The regulation of CF gene expression is not fully understood. We report that interferon-gamma (IFN-gamma), but not IFN-alpha or -beta, downregulates CFTR mRNA levels in two colon-derived epithelial cell lines, HT-29 and T84, in a time- and concentration (from 0.1 IU/ml)-dependent manner. IFN-gamma has no effect on the transcription rate of the CFTR gene but reduces CFTR mRNA half-life, indicating that it exerts a posttranscriptional regulation of CFTR expression, at least partly, through destabilization of the transcripts. Cells treated with IFN-gamma contain subnormal amounts of 165-kDa CFTR protein. Assays of adenosine 3',5'-cyclic monophosphate-stimulated 36Cl- efflux and whole cell currents show that CFTR function is diminished in IFN-gamma-treated cells. IFN-gamma and tumor necrosis factor-alpha synergistically reduce CFTR gene expression. Our results suggest that production of these cytokines in response to bacterial infections and inflammatory disorders may alter transmembrane Cl- transport.

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Human mononuclear cells express 12-LX: coordinated mRNA regulation with 5-LX and FLAP genes

Blood ◽

10.1182/blood.v87.1.331.bloodjournal871331 ◽

1996 ◽

Vol 87 (1) ◽

pp. 331-340

Author(s):

WE Kaminski ◽

E Jendraschak ◽

K Baumann ◽

R Kiefl ◽

S Fischer ◽

...

Keyword(s):

Gene Expression ◽

Mrna Expression ◽

Time Course ◽

Cell Activation ◽

Mononuclear Cells ◽

Constitutive Expression ◽

Ionophore A23187 ◽

Mrna Levels ◽

Rt Pcr ◽

Human Mononuclear Cells

Lipoxygenases (LXs) catalyze formation of leukotrienes and hydroxy-eicosatetraenoic acids (HETEs), proinflammatory, and spasmogenic autacoids that are critical for host defense systems. We studied the expression and regulation of LX genes (12-LX, 5-LX, and 15-LX) and the 5-lipoxygenase activating protein (FLAP) in human mononuclear cells (MNC) and granulocytes using a quantitative reverse transcription polymerase chain reaction (RT-PCR) technique. We show that 12-LX mRNA is constitutively expressed in resting platelet-free MNC. 12-LX gene expression was upregulated by activation with lipopolysaccharide (LPS). The formation of 12-HETE was inducible with ionophore in MNC, as assessed by high-performance liquid chromatography (HPLC) and gas chromatography, and increased after LPS pretreatment. In addition to 12- LX, resting MNC expressed the genes for 5-LX and FLAP constitutively. Quantitative time course analyses of 12-LX, 5-LX, and FLAP gene expression suggested coregulation of 12-LX and FLAP mRNAs, and reciprocal regulation of 5-LX and FLAP mRNAs. During cell stimulation with LPS 5-LX mRNA levels remained unchanged, whereas FLAP gene expression increased. No 15-LX mRNA expression or 15-HETE formation was detectable in unstimulated and activated MNC. In contrast to MNC, quantitative RT-PCR mRNA analysis showed intermittent intraindividual expression of the 5-LX and FLAP genes in resting granulocytes. mRNAs for 12-LX and 15-LX were not expressed. On stimulation of granulocytes ex vivo, mRNA expression of 5-LX and FLAP was upregulated. Stimulation by LPS differed from that by ionophore A23187. Neither LPS nor ionophore induced gene expression of 12-LX or 15-LX in granulocytes. Our data indicate that resting human MNC and granulocytes express LX and FLAP genes in a cell-specific manner. Cell activation induces coordinated upregulation of 12-LX and FLAP genes in MNC, and 5-LX and FLAP genes in granulocytes, respectively. The constitutive expression of 12-LX mRNA, its upregulation on cell activation, and the formation of 12-HETE clearly indicate the presence of a functional 12-LX in human MNC.

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Metformin Collaborates With PINK1/Mfn2 Overexpression Prevented Isoproterenol-Induced Cardiomyocyte Injury By Improving Mitochondrial Function

10.21203/rs.3.rs-680629/v1 ◽

2021 ◽

Author(s):

Zhuang Ma ◽

Zuheng Liu ◽

Yuting Xue ◽

Hao Zhang ◽

Wenjun Xiong ◽

...

Keyword(s):

Membrane Potential ◽

Energy Metabolism ◽

Mitochondrial Membrane Potential ◽

Mitochondrial Biogenesis ◽

Mitochondrial Membrane ◽

Mitochondrial Morphology ◽

Dependent Manner ◽

Combination Strategy ◽

Mitochondrial Energy Metabolism ◽

Atp Production

Abstract Background: Both mitochondrial quality control and energy metabolism are critical in maintaining the physiological function of cardiomyocytes. Previous studies indicated that PGC-1α is a transcription co-activator in promoting mitochondrial energy metabolism which would be beneficial for cardiomyocytes. However, PGC-1α overexpression in heart tissues could also result in the development of cardiomyopathy. This discrepancy in vivo and in vitro might be due to neglecting the elimination of damaged mitochondrial. Thus, an integration strategy of mitochondrial biogenesis and mitophagy might be beneficial.Methods: We studied the function of PINK1 in mitophagy in isoproterenol (Iso)-induced cardiomyocyte injury. Adenovirus was used to provoke an overexpression of the PINK1/Mfn2 protein. Mitochondrial morphology was examined via electron microscopy and confocal microscopy. Cardiomyocytes injury were measured by mitochondrial membrane potential (MMP), reactive oxygen species (ROS) and apoptosis. Metformin was used to increase mitochondrial biogenesis, the level of which was detected via immunoblotting. Additionally, mitochondrial respiratory function was measured by ATP production and oxygen consumption rate (OCR). Results: Cardiomyocytes treated with Iso had high levels of PINK1 and low levels of Mfn2 in a time-dependent manner. PINK1 overexpression promoted mitophagy, alleviated Iso-induced reduction in MMP, reduced ROS production and the apoptotic rate. In addition to increasing mitophagy, metformin could promote mitochondrial biogenensis and the overexpression of Mfn2 induce mitochondrial fusion. Moreover, metformin treatment and PINK1/Mfn2 overexpression reduced the mitochondrial dysfunction by inhibiting the generation of ROS, and leading to an increase in both ATP production and mitochondrial membrane potential in Iso-induced cardiomyocytes injury. Conclusion: Our findings indicate that a combination strategy may help ameliorate myocardial injury through mitophagy and mitochondrial biogenesis.

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Abstract 14356: Blood Tests That Improve the Accuracy of a Brugada Syndrome Diagnosis

Circulation ◽

10.1161/circ.132.suppl_3.14356 ◽

2015 ◽

Vol 132 (suppl_3) ◽

Author(s):

Anyu Zhou ◽

Ning Jinag ◽

Marco Denegri ◽

An Xie ◽

Guangbin Shi ◽

...

Keyword(s):

Gene Expression ◽

Mrna Expression ◽

Brugada Syndrome ◽

Roc Analysis ◽

White Blood Cells ◽

Control Group ◽

Mrna Levels ◽

Operating Characteristics ◽

Optimal Cutoff ◽

Scn5a Mutation

Objectives: To discover the role of altered gene expression regulation in Brugada Syndrome (BrS) and to find biomarkers for BrS diagnosis. Methods: Twenty-five control patients (Control), 25 BrS patients without SCN5A mutation (SCN5A(-)) and 20 BrS patients with SCN5A mutation (SCN5A(+)) were included in this study. Specified gene expression of white blood cells (WBC) were measured by RT-qPCR using TaqMan® Gene Expression assay. Results: MEF2C and MESP1 are the two major cardiac specific transcription factors expressed in WBC. The mRNA expression levels of SCN5A, MEF2C and HuR, one of mRNA stabilizers, were decreased in the SCN5A (+) group (P=0.047, 0.02, 0.000 vs. control group, respectively). The mRNA expression of MESP1 in WBCs was significantly lower in both SCN5A(-) (P=0.012 vs. control) and SCN5A(+) (P=0.000 vs. control) groups. There was no difference between the two BrS groups in MESP1 expression (P=0.215). The area under the Receiver Operating Characteristics (ROC) analysis curve for prediction of BrS using MESP1 levels was 0.775 (95% CI 0.668, 0.882, asymptotic Sig.=0.000). At the optimal cutoff, the corresponding maximum sensitivity and specificity were 0.62 (95% CI: 0.47, 0.76) and 0.88 (0.69, 0.97), respectively. The diagnostic odds ratio (DOR) of MESP1 for BrS diagnosis was 11.96 (95% CI: 5.79, 24.73). The assessment of the mRNA levels in blood SCN5A, MEF2C and HuR were useful for predicting BrS patients with an SCN5A mutation. The area under the ROC analysis curve for prediction of BrS with an SCN5A mutation using SCN5A, MEF2C and HuR mRNA levels in WBCs was 0.847 (95% CI 0.752, 0.942, asymptotic Sig.=0.000), 0.685 (95% CI 0.542, 0.828, asymptotic Sig.=0.016) and 0.777 (95% CI 0.652, 0.902, asymptotic Sig.=0.000), respectively. At the optimal cutoff, the DOR of SCN5A, MEF2C and HuR for SCN5A(+) BrS diagnosis was 17.5 (95% CI: 8.06, 37.86), 4.9 (95% CI: 2.61, 9.17) and 23.5 (95% CI: 9.39, 58.80), respectively. Conclusions: Our results suggest that assessment of circulating MESP1 may be used as a biomarker for BrS diagnosis while decreased SCN5A, MEF2C and HuR mRNA in WBCs is associated with BrS patients with an SCN5A mutation. Our results also suggest that decreased expression of SCN5A, MEF2C, MESP1, and HuR may be pathophysiologically related to BrS.

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Changes in Gene Expression of the MCU Complex Are Induced by Electrical Stimulation in Adult Skeletal Muscle

Frontiers in Physiology ◽

10.3389/fphys.2020.601313 ◽

2021 ◽

Vol 11 ◽

Author(s):

Esteban R. Quezada ◽

Alexis Díaz-Vegas ◽

Enrique Jaimovich ◽

Mariana Casas

Keyword(s):

Gene Expression ◽

Skeletal Muscle ◽

Electrical Stimulation ◽

Muscle Fibers ◽

Low Frequency ◽

Extracellular Atp ◽

Mrna Levels ◽

Dependent Manner ◽

Adult Skeletal Muscle ◽

Muscle Plasticity

The slow calcium transient triggered by low-frequency electrical stimulation (ES) in adult muscle fibers and regulated by the extracellular ATP/IP3/IP3R pathway has been related to muscle plasticity. A regulation of muscular tropism associated with the MCU has also been described. However, the role of transient cytosolic calcium signals and signaling pathways related to muscle plasticity over the regulation of gene expression of the MCU complex (MCU, MICU1, MICU2, and EMRE) in adult skeletal muscle is completely unknown. In the present work, we show that 270 0.3-ms-long pulses at 20-Hz ES (and not at 90 Hz) transiently decreased the mRNA levels of the MCU complex in mice flexor digitorum brevis isolated muscle fibers. Importantly, when ATP released after 20-Hz ES is hydrolyzed by the enzyme apyrase, the repressor effect of 20 Hz on mRNA levels of the MCU complex is lost. Accordingly, the exposure of muscle fibers to 30 μM exogenous ATP produces the same effect as 20-Hz ES. Moreover, the use of apyrase in resting conditions (without ES) increased mRNA levels of MCU, pointing out the importance of extracellular ATP concentration over MCU mRNA levels. The use of xestospongin B (inhibitor of IP3 receptors) also prevented the decrease of mRNA levels of MCU, MICU1, MICU2, and EMRE mediated by a low-frequency ES. Our results show that the MCU complex can be regulated by electrical stimuli in a frequency-dependent manner. The changes observed in mRNA levels may be related to changes in the mitochondria, associated with the phenotypic transition from a fast- to a slow-type muscle, according to the described effect of this stimulation frequency on muscle phenotype. The decrease in mRNA levels of the MCU complex by exogenous ATP and the increase in MCU levels when basal ATP is reduced with the enzyme apyrase indicate that extracellular ATP may be a regulator of the MCU complex. Moreover, our results suggest that this regulation is part of the axes linking low-frequency stimulation with ATP/IP3/IP3R.

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Chronic intrauterine pulmonary hypertension decreases calcium-sensitive potassium channel mRNA expression

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.2000.279.5.l857 ◽

2000 ◽

Vol 279 (5) ◽

pp. L857-L862 ◽

Cited By ~ 12

Author(s):

David N. Cornfield ◽

Ernesto R. Resnik ◽

Jean M. Herron ◽

Steven H. Abman

Keyword(s):

Gene Expression ◽

Pulmonary Hypertension ◽

Mrna Expression ◽

Internal Control ◽

Vascular Reactivity ◽

Ductus Arteriosus ◽

Critical Role ◽

Mrna Levels ◽

Channel Gene ◽

Mrna Content

Calcium-sensitive potassium (KCa) channels play a critical role in mediating perinatal pulmonary vasodilation. Because infants with persistent pulmonary hypertension of the newborn (PPHN) have blunted vasodilator responses to birth-related stimuli, we hypothesized that lung KCachannel gene expression is decreased in PPHN. To test this hypothesis, we measured KCa channel gene expression in distal lung homogenates from both fetal lambs with severe pulmonary hypertension caused by prolonged compression of the ductus arteriosus and age-matched, sham-operated animals (controls). After at least 9 days of compression of the ductus arteriosus, fetal lambs were killed. To determine lung KCa channel mRNA levels, primers were designed against the known sequence of the KCa channel and used in semiquantitative RT-PCR, with lung 18S rRNA content as an internal control. Compared to that in control lambs, lung KCa channel mRNA content in the PPHN group was reduced by 26 ± 6% ( P < 0.02), whereas lung voltage-gated K+ 2.1 mRNA content was unchanged. We conclude that lung KCa channel mRNA expression is decreased in an ovine model of PPHN. Decreased KCa channel gene expression may contribute to the abnormal pulmonary vascular reactivity associated with PPHN.

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