Dataset Information

Cerebral artery alpha-1 AR subtypes: high altitude long-term acclimatization responses.

ABSTRACT: In response to hypoxia and other stress, the sympathetic (adrenergic) nervous system regulates arterial contractility and blood flow, partly through differential activities of the alpha1 (?1) - adrenergic receptor (AR) subtypes (?1A-, ?1B-, and ?1D-AR). Thus, we tested the hypothesis that with acclimatization to long-term hypoxia (LTH), contractility of middle cerebral arteries (MCA) is regulated by changes in expression and activation of the specific ?1-AR subtypes. We conducted experiments in MCA from adult normoxic sheep maintained near sea level (300 m) and those exposed to LTH (110 days at 3801 m). Following acclimatization to LTH, ovine MCA showed a 20% reduction (n?=?5; P<0.05) in the maximum tension achieved by 10-5 M phenylephrine (PHE). LTH-acclimatized cerebral arteries also demonstrated a statistically significant (P<0.05) inhibition of PHE-induced contractility in the presence of specific ?1-AR subtype antagonists. Importantly, compared to normoxic vessels, there was significantly greater (P<0.05) ?1B-AR subtype mRNA and protein levels in LTH acclimatized MCA. Also, our results demonstrate that extracellular regulated kinase 1 and 2 (ERK1/2)-mediated negative feedback regulation of PHE-induced contractility is modulated by ?1B-AR subtype. Overall, in ovine MCA, LTH produces profound effects on ?1-AR subtype expression and function.

SUBMITTER: Goyal R

PROVIDER: S-EPMC4231100 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature

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Cerebral artery alpha-1 AR subtypes: high altitude long-term acclimatization responses.

Goyal Ravi R Goyal Dipali D Chu Nina N Van Wickle Jonathan J Longo Lawrence D LD

PloS one 20141113 11

In response to hypoxia and other stress, the sympathetic (adrenergic) nervous system regulates arterial contractility and blood flow, partly through differential activities of the alpha1 (α1) - adrenergic receptor (AR) subtypes (α1A-, α1B-, and α1D-AR). Thus, we tested the hypothesis that with acclimatization to long-term hypoxia (LTH), contractility of middle cerebral arteries (MCA) is regulated by changes in expression and activation of the specific α1-AR subtypes. We conducted experiments in ...[more]

PMID: 25393740

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Project description:In humans and other species, Longlong-term hypoxia (LTH) during pregnancy can lead to intrauterine growth restriction with reduced body/brain weight, dysregulation of cerebral blood flow (CBF), and other problems in humans and rodents. In contrast, sheep appear to undergo relatively successful acclimatization, not demonstrating any of the above-mentioned problems except at extremely high altitude. To identify the signal transduction genetic pathways and those critical molecules, which may be involved in acclimatization to high altitude LTH, we conducted microarray with advanced bioinformatic analysis on carotid arteries (CA) from the normoxic near-term ovine fetus at sea-level and those acclimatized to high altitude for 110+ days during gestation. In response to LTH acclimatization, in fetal CA we identified, mRNA from 38 genes upregulated (> 2 fFold; (P < 0.05) and 9 genes downregulated (> 2-f Fold; (P < 0.05). The major genes with upregulated mRNA were SLC1A3, Insulin-like growth factor (IGF) binding protein 3, IGF type 2 receptor, transforming growth factor (TGF) Beta-3, and genes involved in the AKT and BCL2 signal transduction networks. The majority of genes with upregulated mRNA have a common motif for Pbx/Knotted homeobox in the promoter region, and Sox family binding sites in the 3M-bM-^@M-^Y un -translated region (UTR). Genes with downregulated mRNA included those involved in the P53 pathway and 5-lipoxygenase activating proteins. The promoter region of all genes with downregulated mRNA, had a common 49 bp region, with a binding site for DOT6 and TOD6, components of the RPD3 histone deacetylase complex RPD3C(L). We also identified miRNA complementary to a number of the altered genes. Thus, the present study identified molecules in the ovine fetus, which may help it to play a role in the acclimatizatione successfully response to high-altitude associated LTH. In these series of experiments we examined changes in gene expression in sheep carotids. Pregnant sheep and non-pregnant adult sheep were exposed to 110 days of hypoxia at 3801 meters of altitude. Carotid arteries from fetuses from non-pregnant adult from sea-level controls and those from high-altitude were compared by Agilent ovine custom array

Project description:High altitude acclimatization and disease have been the centerpiece of investigations concerning human health at high altitude. Almost all investigations have focused on either understanding and ameliorating high altitude disease or finding better methods of acclimatization/training at high altitude. The aspect of altitude de-induction/de-acclimatization has remained clouded despite the fact that it was documented since the first decade of twentieth century. A few recent studies, particularly in China, have stated unanimously that high altitude de-acclimatization involved multiple observable clinical symptoms ranging from headache to abdominal distention. These symptoms have been collectively referred to as "high altitude de-acclimatization syndrome" (HADAS). However, computational omics and network biology centric investigations concerning HADAS are nascent. In this study, we focus on the quantitative proteo-informatics, especially network biology, of human plasma proteome in individuals who successfully descended from high altitude areas after a stay of 120 days. In brief, the protein list was uploaded into STRING and IPA to compute z-score based cut-offs which were used to analyze the directionality and significance of various identified protein networks as well as the proteins within them. Relevant upstream regulators extracted using computational strategies were also validated. Time-points till the 180th day of de-induction have been investigated to comparatively assess the changes in the plasma proteome and protein pathways of such individuals since the 7th day of arrival at altitude. Our investigation revealed extensive effects of de-induction on lipid metabolism, inflammation and innate immune system as well as coagulation system. This novel study provides a conceptual framework for formulating therapeutic strategies to ease the symptoms of HADAS during de-acclimatization. Such strategies should focus on normalization of lipid metabolism, inflammatory signaling and coagulation systems.

Dataset Information

Cerebral artery alpha-1 AR subtypes: high altitude long-term acclimatization responses.

Publications

Cerebral artery alpha-1 AR subtypes: high altitude long-term acclimatization responses.

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